Publications by authors named "Tamás Kiss"

186 Publications

The 7SK/P-TEFb snRNP controls ultraviolet radiation-induced transcriptional reprogramming.

Cell Rep 2021 Apr;35(2):108965

Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France. Electronic address:

Conversion of promoter-proximally paused RNA polymerase II (RNAPII) into elongating polymerase by the positive transcription elongation factor b (P-TEFb) is a central regulatory step of mRNA synthesis. The activity of P-TEFb is controlled mainly by the 7SK small nuclear ribonucleoprotein (snRNP), which sequesters active P-TEFb into inactive 7SK/P-TEFb snRNP. Here we demonstrate that under normal culture conditions, the lack of 7SK snRNP has only minor impacts on global RNAPII transcription without detectable consequences on cell proliferation. However, upon ultraviolet (UV)-light-induced DNA damage, cells lacking 7SK have a defective transcriptional response and reduced viability. Both UV-induced release of "lesion-scanning" polymerases and activation of key early-responsive genes are compromised in the absence of 7SK. Proper induction of 7SK-dependent UV-responsive genes requires P-TEFb activity directly mobilized from the nucleoplasmic 7SK/P-TEFb snRNP. Our data demonstrate that the primary function of the 7SK/P-TEFb snRNP is to orchestrate the proper transcriptional response to stress.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2021.108965DOI Listing
April 2021

IGF1R signaling regulates astrocyte-mediated neurovascular coupling in mice: implications for brain aging.

Geroscience 2021 Apr 6;43(2):901-911. Epub 2021 Mar 6.

Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.

Aging is associated with a significant deficiency in circulating insulin-like growth factor-1 (IGF-1), which has an important role in the pathogenesis of age-related vascular cognitive impairment (VCI). Impairment of moment-to-moment adjustment of regional cerebral blood flow via neurovascular coupling (NVC) importantly contributes to VCI. Previous studies established a causal link between circulating IGF-1 deficiency and neurovascular dysfunction. Release of vasodilator mediators from activated astrocytes plays a key role in NVC. To determine the impact of impaired IGF-1 signaling on astrocytic function, astrocyte-mediated NVC responses were studied in a novel mouse model of astrocyte-specific knockout of IGF1R (GFAP-Cre/Igf1r) and accelerated neurovascular aging. We found that mice with disrupted astrocytic IGF1R signaling exhibit impaired NVC responses, decreased stimulated release of the vasodilator gliotransmitter epoxy-eicosatrienoic acids (EETs), and upregulation of soluble epoxy hydrolase (sEH), which metabolizes and inactivates EETs. Collectively, our findings provide additional evidence that IGF-1 promotes astrocyte health and maintains normal NVC, protecting cognitive health.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-021-00350-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110646PMC
April 2021

Demonstration of age-related blood-brain barrier disruption and cerebromicrovascular rarefaction in mice by longitudinal intravital two-photon microscopy and optical coherence tomography.

Am J Physiol Heart Circ Physiol 2021 04 5;320(4):H1370-H1392. Epub 2021 Feb 5.

Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center For Geroscience and Healthy Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.

Age-related blood-brain barrier (BBB) disruption and cerebromicrovascular rarefaction contribute importantly to the pathogenesis of both vascular cognitive impairment and dementia (VCID) and Alzheimer's disease (AD). Recent advances in geroscience research enable development of novel interventions to reverse age-related alterations of the cerebral microcirculation for prevention of VCID and AD. To facilitate this research, there is an urgent need for sensitive and easy-to-adapt imaging methods that enable longitudinal assessment of changes in BBB permeability and brain capillarization in aged mice and that could be used in vivo to evaluate treatment efficiency. To enable longitudinal assessment of changes in BBB permeability in aged mice equipped with a chronic cranial window, we adapted and optimized two different intravital two-photon imaging approaches. By assessing relative fluorescence changes over the baseline within a volume of brain tissue, after qualitative image subtraction of the brain microvasculature, we confirmed that, in 24-mo-old C57BL/6J mice, cumulative permeability of the microvessels to fluorescent tracers of different molecular masses (0.3 to 40 kDa) is significantly increased compared with that of 5-mo-old mice. Real-time recording of vessel cross-sections showed that apparent solute permeability of single microvessels is significantly increased in aged mice vs. young mice. Cortical capillary density, assessed both by intravital two-photon microscopy and optical coherence tomography was also decreased in aged mice vs. young mice. The presented methods have been optimized for longitudinal (over the period of 36 wk) in vivo assessment of cerebromicrovascular health in preclinical geroscience research. Methods are presented for longitudinal detection of age-related increase in blood-brain barrier permeability and microvascular rarefaction in the mouse cerebral cortex by intravital two-photon microscopy and optical coherence tomography.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1152/ajpheart.00709.2020DOI Listing
April 2021

Obesity-induced cognitive impairment in older adults: a microvascular perspective.

Am J Physiol Heart Circ Physiol 2021 02 18;320(2):H740-H761. Epub 2020 Dec 18.

Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.

Over two-thirds of individuals aged 65 and older are obese or overweight in the United States. Epidemiological data show an association between the degree of adiposity and cognitive dysfunction in the elderly. In this review, the pathophysiological roles of microvascular mechanisms, including impaired endothelial function and neurovascular coupling responses, microvascular rarefaction, and blood-brain barrier disruption in the genesis of cognitive impairment in geriatric obesity are considered. The potential contribution of adipose-derived factors and fundamental cellular and molecular mechanisms of senescence to exacerbated obesity-induced cerebromicrovascular impairment and cognitive decline in aging are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1152/ajpheart.00736.2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8091942PMC
February 2021

Acute blockade of NR2C/D subunit-containing N-methyl-D-aspartate receptors modifies sleep and neural oscillations in mice.

J Sleep Res 2020 Dec 13:e13257. Epub 2020 Dec 13.

Department of Computational Sciences, Wigner Research Centre for Physics, Budapest, Hungary.

N-methyl-d-aspartate receptors (NMDARs) play an important role in excitatory neurotransmission and have been associated with psychiatric conditions including schizophrenia and major depressive disorder. NMDARs are composed of two NR1 and two NR2 subunits. The type of NR2 subunit determines electrophysiological and pharmacological properties of the receptor. As the precise role of NR2C/D subunit-containing NMDARs is poorly understood in vivo, we have performed behavioural, quantitative electroencephalographic (qEEG) and polysomnographic analysis following acute pharmacological blockade of these receptor subtypes in adult male CD1 mice. We found that NR2C/D blockade impaired motor coordination and decreased the amount of gross movement. Moreover, EEG power in multiple frequency bands including theta and sigma were found to decrease significantly together with a decrease of theta oscillation frequency. Changes of these qEEG measures were accompanied by a decrease in time spent in slow-wave and rapid eye movement sleep, but an increase of time spent in quiet wakefulness. Furthermore, there was a significant decrease of sleep spindle oscillation density. These findings highlight the importance of NR2C/D-containing NMDARs and take a step towards establishing a link between electrophysiological correlates of psychiatric disorders and underlying synaptic dysfunctions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jsr.13257DOI Listing
December 2020

Ameliorated Autoimmune Arthritis and Impaired B Cell Receptor-Mediated Ca Influx in Nkx2-3 Knock-out Mice.

Int J Mol Sci 2020 Aug 26;21(17). Epub 2020 Aug 26.

Department of Immunology and Biotechnology, Medical School, University of Pécs, 7624 Pécs, Hungary.

B cells play a crucial role in the pathogenesis of rheumatoid arthritis. In Nkx2-3-deficient mice (Nkx2-3) the spleen's histological structure is fundamentally changed; therefore, B cell homeostasis is seriously disturbed. Based on this, we were curious, whether autoimmune arthritis could be induced in Nkx2-3 mice and how B cell activation and function were affected. We induced arthritis with immunization of recombinant human proteoglycan aggrecan G1 domain in Nkx2-3 and control BALB/c mice. We followed the clinical picture, characterized the radiological changes, the immune response, and intracellular Ca signaling of B cells. Incidence of the autoimmune arthritis was lower, and the disease severity was milder in Nkx2-3 mice than in control BALB/c mice. The radiological changes were in line with the clinical picture. In Nkx2-3 mice, we measured decreased antigen-induced proliferation and cytokine production in spleen cell cultures; in the sera, we found less anti-CCP-IgG2a, IL-17 and IFNγ, but more IL-1β, IL-4 and IL-6. B cells isolated from the lymph nodes of Nkx2-3 mice showed decreased intracellular Ca signaling compared to those isolated from BALB/c mice. Our findings show that the transcription factor Nkx2-3 might regulate the development of autoimmune arthritis most likely through modifying B cell activation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21176162DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7503974PMC
August 2020

Increases in hypertension-induced cerebral microhemorrhages exacerbate gait dysfunction in a mouse model of Alzheimer's disease.

Geroscience 2020 12 25;42(6):1685-1698. Epub 2020 Aug 25.

Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.

Clinical studies show that cerebral amyloid angiopathy (CAA) associated with Alzheimer's disease (AD) and arterial hypertension are independent risk factors for cerebral microhemorrhages (CMHs). To test the hypothesis that amyloid pathology and hypertension interact to promote the development of CMHs, we induced hypertension in the Tg2576 mouse model of AD and respective controls by treatment with angiotensin II (Ang II) and the NO synthesis inhibitor L-NAME. The number, size, localization, and neurological consequences (gait alterations) of CMHs were compared. We found that compared to control mice, in TG2576 mice, the same level of hypertension led to significantly increased CMH burden and exacerbation of CMH-related gait alterations. In hypertensive TG2576 mice, CMHs were predominantly located in the cerebral cortex at the cortical-subcortical boundary, mimicking the clinical picture seen in patients with CAA. Collectively, amyloid pathologies exacerbate the effects of hypertension, promoting the genesis of CMHs, which likely contribute to their deleterious effects on cognitive function. Therapeutic strategies for prevention of CMHs that reduce blood pressure and preserve microvascular integrity are expected to exert neuroprotective effects in high-risk elderly AD patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-020-00256-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7732885PMC
December 2020

Characterization of PF-6142, a Novel, Non-Catecholamine Dopamine Receptor D1 Agonist, in Murine and Nonhuman Primate Models of Dopaminergic Activation.

Front Pharmacol 2020 7;11:1005. Epub 2020 Jul 7.

Global Research and Development, Pfizer Inc., Groton, CT, United States.

Selective activation of dopamine D1 receptors remains a promising pro-cognitive therapeutic strategy awaiting robust clinical investigation. PF-6142 is a key example from a recently disclosed novel series of non-catechol agonists and partial agonists of the dopamine D1/5 receptors (D1R) that exhibit pharmacokinetic (PK) properties suitable for oral delivery. Given their reported potential for functionally biased signaling compared to known catechol-based selective agonists, and the promising rodent PK profile of PF-6142, we utilized relevant assays in male rodents and male and female non-human primates (NHP) to evaluate the pharmacology of this new series. Studies in rodents showed that PF-6142 increased locomotor activity and prefrontal cortex acetylcholine release, increased time spent in wakefulness, and desynchronized the EEG, like known D1R agonists. D1R selectivity of PF-6142 was supported by lack of effect in D1R knock-out mice and blocked response in the presence of the D1R antagonist SCH-23390. Further, PF-6142 improved performance in rodent models of NMDA receptor antagonist-induced cognitive dysfunction, such as MK-801-disrupted paired-pulse facilitation, and ketamine-disrupted working memory performance in the radial arm maze. Similarly, PF-6142 reversed ketamine-induced deficits in NHP performing the spatial delayed recognition task. Of importance, PF-6142 did not alter the efficacy of risperidone in assays predictive of antipsychotic-like effect in rodents including pre-pulse inhibition and conditioned avoidance responding. These data support the continued development of non-catechol based D1R agonists for the treatment of cognitive impairment associated with brain disorders including schizophrenia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphar.2020.01005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7358525PMC
July 2020

Marginal and internal fit of full ceramic crowns milled using CADCAM systems on cadaver full arch scans.

BMC Oral Health 2020 07 6;20(1):189. Epub 2020 Jul 6.

Department of Oral Rehabilitation, College of Dental Medicine, Medical University of South Carolina, Charleston, SC, USA.

Background: Chairside systems are becoming more popular for fabricating full-ceramic single restorations, but there is very little knowledge about the effect of the entire workflow process on restoration fit. Therefore, this study aimed to compare the absolute marginal discrepancy (AMD) and the full internal fit (FULL) of all-ceramic crowns made by two chairside systems, Planmeca FIT and CEREC, with detailed and standard mill settings.

Methods: One upper molar was prepared for an all-ceramic crown in human cadaver maxilla. Full-arch scans were made by Emerald or Omnicam four times each. Twenty-four e.max crowns were designed and milled by the Planmill 30s or 40s or CEREC MCXL mills with either detailed or standard settings. The cadaver tooth was extracted, and each crown was fixed on it and scanned by a high-resolution microCT scanner. The AMD and FULL were measured digitally in mesio-distal and bucco-lingual 2D slices. The actual and predicted times of the milling were also registered.

Results: No differences were observed between detailed or standard settings in either system. The AMD was significantly higher with CEREC (132 ± 12 μm) than with either Planmill 30s (71 ± 6.9 μm) or 40s (78 ± 7.7 μm). In standard mode, the FULL was significantly higher with CEREC (224 ± 9.6 μm) than with either Planmill 30s (169 ± 8.1 μm) or 40s (178 ± 8.5 μm). There was no difference between actual and predicted time with the two Planmeca models, but with CEREC, the actual time was significantly higher than the predicted time. The 30s had significantly higher actual and predicted times compared to all other models. Across all models, the average milling time was 7.2 min less in standard mode than in detailed mode.

Conclusions: All fit parameters were in an acceptable range. No differences in fit between Planmeca models suggest no effect of spindle number on accuracy. The detailed setting has no improvement in the marginal or internal fit of the restoration, yet it increases milling time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12903-020-01181-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7339429PMC
July 2020

Complex Regulatory Role of the TRPA1 Receptor in Acute and Chronic Airway Inflammation Mouse Models.

Int J Mol Sci 2020 Jun 9;21(11). Epub 2020 Jun 9.

Department of Pharmacology and Pharmacotherapy, Medical School and János Szentágothai Research Centre & Centre for Neuroscience, University of Pécs, H-7624 Pécs, Hungary.

The Transient Receptor Potential Ankyrin 1 (TRPA1) cation channel expressed on capsaicin-sensitive afferents, immune and endothelial cells is activated by inflammatory mediators and exogenous irritants, e.g., endotoxins, nicotine, crotonaldehyde and acrolein. We investigated its involvement in acute and chronic pulmonary inflammation using gene-deleted () mice. Acute pneumonitis was evoked by intranasal endotoxin (lipopolysaccharide: LPS) administration, chronic bronchitis by daily cigarette smoke exposure (CSE) for 4 months. Frequency, peak inspiratory/expiratory flows, minute ventilation determined by unrestrained whole-body plethysmography were significantly greater, while tidal volume, inspiratory/expiratory/relaxation times were smaller in mice. LPS-induced bronchial hyperreactivity, myeloperoxidase activity, frequency-decrease were significantly greater in mice. CSE significantly decreased tidal volume, minute ventilation, peak inspiratory/expiratory flows in wildtypes, but not in mice. CSE remarkably increased the mean linear intercept (histopathology), as an emphysema indicator after 2 months in wildtypes, but only after 4 months in mice. Semiquantitative histopathological scores were not different between strains in either models. TRPA1 has a complex role in basal airway function regulation and inflammatory mechanisms. It protects against LPS-induced acute pneumonitis and hyperresponsiveness, but is required for CSE-evoked emphysema and respiratory deterioration. Further research is needed to determine TRPA1 as a potential pharmacological target in the lung.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21114109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7312832PMC
June 2020

Single-cell RNA sequencing identifies senescent cerebromicrovascular endothelial cells in the aged mouse brain.

Geroscience 2020 04 31;42(2):429-444. Epub 2020 Mar 31.

Department of Biochemistry and Molecular Biology, Reynolds Oklahoma Center on Aging/Center for Geroscience and Healthy Brain Aging, Vascular Cognitive Impairment and Neurodegeneration Program, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma City, OK, 73104, USA.

Age-related phenotypic changes of cerebromicrovascular endothelial cells lead to dysregulation of cerebral blood flow and blood-brain barrier disruption, promoting the pathogenesis of vascular cognitive impairment (VCI). In recent years, endothelial cell senescence has emerged as a potential mechanism contributing to microvascular pathologies opening the avenue to the therapeutic exploitation of senolytic drugs in preclinical studies. However, difficulties with the detection of senescent endothelial cells in wild type mouse models of aging hinder the assessment of the efficiency of senolytic treatments. To detect senescent endothelial cells in the aging mouse brain, we analyzed 4233 cells in fractions enriched for cerebromicrovascular endothelial cells and other cells associated with the neurovascular unit obtained from young (3-month-old) and aged (28-month-old) C57BL/6 mice. We define 13 transcriptomic cell types by deep, single-cell RNA sequencing. We match transcriptomic signatures of cellular senescence to endothelial cells identified on the basis of their gene expression profile. Our study demonstrates that with advanced aging, there is an increased ratio of senescent endothelial cells (~ 10%) in the mouse cerebral microcirculation. We propose that our single-cell RNA sequencing-based method can be adapted to study the effect of aging on senescence in various brain cell types as well as to evaluate the efficiency of various senolytic regimens in multiple tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-020-00177-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205992PMC
April 2020

Circulating anti-geronic factors from heterochonic parabionts promote vascular rejuvenation in aged mice: transcriptional footprint of mitochondrial protection, attenuation of oxidative stress, and rescue of endothelial function by young blood.

Geroscience 2020 04 15;42(2):727-748. Epub 2020 Mar 15.

Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.

Aging-induced functional and phenotypic alterations of the vasculature (e.g., endothelial dysfunction, oxidative stress) have a central role in morbidity and mortality of older adults. It has become apparent in recent years that cell autonomous mechanisms alone are inadequate to explain all aspects of vascular aging. The present study was designed to test the hypothesis that age-related changes in circulating anti-geronic factors contribute to the regulation of vascular aging processes in a non-cell autonomous manner. To test this hypothesis, through heterochronic parabiosis we determined the extent, if any, to which endothelial function, vascular production of ROS, and shifts in the vascular transcriptome (RNA-seq) are modulated by the systemic environment. We found that in aortas isolated from isochronic parabiont aged (20-month-old) C57BL/6 mice [A-(A); parabiosis for 8 weeks] acetylcholine-induced endothelium-dependent relaxation was impaired and ROS production (dihydroethidium fluorescence) was increased as compared with those in aortas from young isochronic parabiont (6-month-old) mice [Y-(Y)]. The presence of young blood derived from young parabionts significantly improved endothelium-dependent vasorelaxation and attenuated ROS production in vessels of heterochronic parabiont aged [A-(Y)] mice. In aortas derived from heterochronic parabiont young [Y-(A)] mice, acetylcholine-induced relaxation and ROS production were comparable with those in aortas derived from Y-(Y) mice. Using RNA-seq we assessed transcriptomic changes in the aortic arch associated with aging and heterochronic parabiosis. We identified 347 differentially expressed genes in A-(A) animals compared with Y-(Y) controls. We have identified 212 discordant genes, whose expression levels differed in the aged phenotype, but have shifted back toward the young phenotype by the presence of young blood in aged A-(Y) animals. Pathway analysis shows that vascular protective effects mediated by young blood-regulated genes include mitochondrial rejuvenation. In conclusion, a relatively short-term exposure to young blood can rescue vascular aging phenotypes, including attenuation of oxidative stress, mitochondrial rejuvenation, and improved endothelial function. Our findings provide additional evidence supporting the significant plasticity of vascular aging and evidence for the existence of anti-geronic factors capable of exerting rejuvenating effects on the aging vasculature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-020-00180-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205954PMC
April 2020

CD82-TRPM7-Numb signaling mediates age-related cognitive impairment.

Geroscience 2020 04 22;42(2):595-611. Epub 2020 Feb 22.

Stephenson Cancer Center and Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, 73104, USA.

Aging is a crucial cause of cognitive decline and a major risk factor for Alzheimer's disease (AD); however, AD's underlying molecular mechanisms remain unclear. Recently, tetraspanins have emerged as important modulators of synaptic function and memory. We demonstrate that the level of tetraspanin CD82 is upregulated in the brains of AD patients and middle-aged mice. In young adult mice, injection of AAV-CD82 to the hippocampus induced AD-like cognitive deficits and impairments in neuronal spine density. CD82 overexpression increased TRPM7 α-kinase cleavage via caspase-3 activation and induced Numb phosphorylation at Thr346 and Ser348 residues. CD82 overexpression promoted beta-amyloid peptide (Aβ) secretion which could be reversed by Numb T346S348 mutants. Importantly, hippocampus-related memory functions were improved in Cd82 mice. Taken together, our findings provide the evidence that links the elevated CD82-TRPM7-Numb signaling to age-related cognitive impairment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-020-00166-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205934PMC
April 2020

Nicotinamide mononucleotide (NMN) supplementation promotes neurovascular rejuvenation in aged mice: transcriptional footprint of SIRT1 activation, mitochondrial protection, anti-inflammatory, and anti-apoptotic effects.

Geroscience 2020 04 13;42(2):527-546. Epub 2020 Feb 13.

Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.

Aging-induced structural and functional alterations of the neurovascular unit lead to impairment of neurovascular coupling responses, dysregulation of cerebral blood flow, and increased neuroinflammation, all of which contribute importantly to the pathogenesis of age-related vascular cognitive impairment (VCI). There is increasing evidence showing that a decrease in NAD availability with age plays a critical role in age-related neurovascular and cerebromicrovascular dysfunction. Our recent studies demonstrate that restoring cellular NAD levels in aged mice rescues neurovascular function, increases cerebral blood flow, and improves performance on cognitive tasks. To determine the effects of restoring cellular NAD levels on neurovascular gene expression profiles, 24-month-old C57BL/6 mice were treated with nicotinamide mononucleotide (NMN), a key NAD intermediate, for 2 weeks. Transcriptome analysis of preparations enriched for cells of the neurovascular unit was performed by RNA-seq. Neurovascular gene expression signatures in NMN-treated aged mice were compared with those in untreated young and aged control mice. We identified 590 genes differentially expressed in the aged neurovascular unit, 204 of which are restored toward youthful expression levels by NMN treatment. The transcriptional footprint of NMN treatment indicates that increased NAD levels promote SIRT1 activation in the neurovascular unit, as demonstrated by analysis of upstream regulators of differentially expressed genes as well as analysis of the expression of known SIRT1-dependent genes. Pathway analysis predicts that neurovascular protective effects of NMN are mediated by the induction of genes involved in mitochondrial rejuvenation, anti-inflammatory, and anti-apoptotic pathways. In conclusion, the recently demonstrated protective effects of NMN treatment on neurovascular function can be attributed to multifaceted sirtuin-mediated anti-aging changes in the neurovascular transcriptome. Our present findings taken together with the results of recent studies using mitochondria-targeted interventions suggest that mitochondrial rejuvenation is a critical mechanism to restore neurovascular health and improve cerebral blood flow in aging.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-020-00165-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7206476PMC
April 2020

Development of Meloxicam-Human Serum Albumin Nanoparticles for Nose-to-Brain Delivery via Application of a Quality by Design Approach.

Pharmaceutics 2020 Jan 25;12(2). Epub 2020 Jan 25.

Faculty of Pharmacy, Institute of Pharmaceutical Technology and Regulatory Affairs, University of Szeged, Szeged H-6720, Hungary.

The aim of this study was to optimize the formulation of meloxicam (MEL)-containing human serum albumin (HSA) nanoparticles for nose-to-brain via a quality by design (QbD) approach. Liquid and dried formulations of nanoparticles containing Tween 80 and without the surfactant were investigated. Various properties, such as the Z-average, zeta potential, encapsulation efficacy (EE), conjugation of MEL and HSA, physical stability, in vitro dissolution, in vitro permeability, and in vivo plasma and brain distribution of MEL were characterized. From a stability point of view, a solid product (Mel-HSA-Tween) is recommended for further development since it met the desired critical parameters (176 ± 0.3 nm Z-average, 0.205 ± 0.01 PdI, -14.1 ± 0.7 mV zeta potential) after 6 months of storage. In vitro examination showed a significantly increased drug dissolution and permeability of MEL-containing nanoparticles, especially in the case of applying Tween 80. The in vivo studies confirmed both the trans-epithelial and axonal transport of nanoparticles, and a significantly higher cerebral concentration of MEL was detected with nose-to-brain delivery, in comparison with intravenous or per os administration. These results indicate intranasal the administration of optimized MEL-containing HSA formulations as a potentially applicable "value-added" product for the treatment of neuroinflammation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/pharmaceutics12020097DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7076499PMC
January 2020

Pharmacological or genetic depletion of senescent astrocytes prevents whole brain irradiation-induced impairment of neurovascular coupling responses protecting cognitive function in mice.

Geroscience 2020 04 20;42(2):409-428. Epub 2020 Jan 20.

Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Oklahoma Center for Geroscience, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 731042, USA.

Whole brain irradiation (WBI, also known as whole brain radiation therapy or WBRT) is a mainstream therapy for patients with identifiable brain metastases and as a prophylaxis for microscopic malignancies. WBI accelerates brain aging, causing progressive cognitive dysfunction in ~ 50% of surviving patients, thus compromising quality of life. The mechanisms responsible for this WBI side effect remain obscure, and there are no effective treatments or prevention strategies. Here, we test the hypothesis that WBI induces astrocyte senescence, which contributes to impaired astrocytic neurovascular coupling (NVC) responses and the genesis of cognitive decline. To achieve this goal, we used transgenic p16-3MR mice, which allows the detection and selective elimination of senescent cells. We subjected these mice to a clinically relevant protocol of fractionated WBI (5 Gy twice weekly for 4 weeks). WBI-treated and control mice were tested for spatial memory performance (radial arm water maze), astrocyte-dependent NVC responses (whisker-stimulation-induced increases in cerebral blood flow, assessed by laser speckle contrast imaging), NVC-related gene expression, astrocytic release of eicosanoid gliotransmitters and the presence of senescent astrocytes (by flow cytometry, immunohistochemistry and gene expression profiling) at 6 months post-irradiation. WBI induced senescence in astrocytes, which associated with NVC dysfunction and impaired performance on cognitive tasks. To establish a causal relationship between WBI-induced senescence and NVC dysfunction, senescent cells were depleted from WBI-treated animals (at 3 months post-WBI) by genetic (ganciclovir treatment) or pharmacological (treatment with the BCL-2/BCL-xL inhibitor ABT263/Navitoclax, a known senolytic drug) means. In WBI-treated mice, both treatments effectively eliminated senescent astrocytes, rescued NVC responses, and improved cognitive performance. Our findings suggest that the use of senolytic drugs can be a promising strategy for preventing the cognitive impairment associated with WBI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-020-00154-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205933PMC
April 2020

The fluorescent dye 3,3'-diethylthiatricarbocyanine iodide is unsuitable for in vivo imaging of myelination in the mouse.

Brain Res Bull 2020 03 16;156:10-14. Epub 2019 Dec 16.

János Szentágothai Research Centre and Centre for Neuroscience, University of Pécs, H-7624 Pécs, Ifjúság út 20, Hungary; Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Szigeti út 12, Hungary. Electronic address:

There is a growing interest to use non-invasive optical imaging methods to study central nervous system diseases. The application of a myelin-binding fluorescent dye, 3,3-diethylthiatricarbocyanine iodide (DBT) was recently described for in vivo optical imaging of demyelination in the mouse. In the present study we aimed at adapting the method to our optical imaging systems, the IVIS Lumina II to measure epifluorescence and the fluorescent molecular tomograph (FMT) for 3-dimensional quantification of the fluorophore. Epifluorescent imaging was performed 5-30 min after DBT injection which was followed by FMT imaging at 40 min. Two mice also underwent micro-CT imaging in the FMT cassette for the purpose of FMT-CT co-registration. Ex vivo imaging of the brain and other tissues of the head and neck was carried out 1 h after injection. Both the FMT-CT co-registration and the ex vivo imaging of organs proved that DBT poorly crossed the blood-brain barrier. The dye did not accumulate in the myelin sheath of the sciatic nerve. In contrast, there was an intense accumulation in the pituitary and salivary glands. The FMT-CT co-registration unequivocally demonstrated that the signal localized to the head did not originate from beyond the blood-brain barrier. No myelin binding was demonstrated by the ex vivo imaging either. In conclusion, DBT is unsuitable for in vivo imaging of myelination due to its poor BBB penetration, accumulation in other structures of the head and neck region and lack of selective binding towards myelin in vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.brainresbull.2019.12.009DOI Listing
March 2020

Lack of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Disturbs Callus Formation.

J Mol Neurosci 2019 Dec 5. Epub 2019 Dec 5.

Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a naturally secreted signaling peptide and has important regulatory roles in the differentiation of the central nervous system and its absence results in disorders in femur development. PACAP has an important function in prevention of oxidative stress or mechanical stress in chondrogenesis but little is known about its function in bone regeneration. A new callus formation model was set to investigate its role in bone remodeling. Fracturing was 5 mm distal from the proximal articular surface of the tibia and the depth was 0.5 mm. Reproducibility of callus formation was investigated with CT 3, 7, and 21 days after the operation. Absence of PACAP did not alter the alkaline phosphatase (ALP) activation in PACAP KO healing process. In developing callus, the expression of collagen type I increased in wild-type (WT) and PACAP KO mice decreased to the end of healing process. Expression of the elements of BMP signaling was disturbed in the callus formation of PACAP KO mice, as bone morphogenic protein 4 (BMP4) and 6 showed an early reduction in bone regeneration. However, elevated Smad1 expression was demonstrated in PACAP KO mice. Our results indicate that PACAP KO mice show various signs of disturbed bone healing and suggest PACAP compensatory and fine tuning effects in proper bone regeneration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12031-019-01448-zDOI Listing
December 2019

Cerebral venous congestion promotes blood-brain barrier disruption and neuroinflammation, impairing cognitive function in mice.

Geroscience 2019 10 5;41(5):575-589. Epub 2019 Nov 5.

Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.

Cognitive impairment is one of the most common co-occurring chronic conditions among elderly heart failure patients (incidence: up to ~ 80%); however, the underlying mechanisms are not completely understood. It is hypothesized that in addition to decreased cardiac output, increases in central-and consequentially, cerebral-venous pressure (backward failure) also contribute significantly to the genesis of cognitive impairment. To test this hypothesis and elucidate the specific pathogenic role of venous congestion in the brain, we have established a novel model of increased cerebral venous pressure: mice with jugular vein ligation (JVL). To test the hypothesis that increased venous pressure in the brain contributes to the development of cognitive deficits by causing blood-brain barrier disruption, dysregulation of blood flow, and/or promoting neuroinflammation, in C57BL/6 mice, the internal and external jugular veins were ligated. Cognitive function (radial arm water maze), gait function (CatWalk), and motor coordination (rotarod) were tested post-JVL. Neurovascular coupling responses were assessed by measuring changes in cerebral blood flow in the whisker barrel cortex in response to contralateral whisker stimulation by laser speckle contrast imaging through a closed cranial window. Blood-brain barrier integrity (IgG extravasation) and microglia activation (Iba1 staining) were assessed in brain slices by immunohistochemistry. Neuroinflammation-related gene expression profile was assessed by a targeted qPCR array. After jugular vein ligation, mice exhibited impaired spatial learning and memory, altered motor coordination, and impaired gait function, mimicking important aspects of altered brain function observed in human heart failure patients. JVL did not alter neurovascular coupling responses. In the brains of mice with JVL, significant extravasation of IgG was detected, indicating blood-brain barrier disruption, which was associated with histological markers of neuroinflammation (increased presence of activated microglia) and a pro-inflammatory shift in gene expression profile. Thus, cerebral venous congestion per se can cause blood-brain barrier disruption and neuroinflammation, which likely contribute to the genesis of cognitive impairment. These findings have relevance to the pathogenesis of cognitive decline associated with heart failure as well as increased cerebal venous pressure due to increased jugular venous reflux in elderly human patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00110-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6885079PMC
October 2019

Treatment with the poly(ADP-ribose) polymerase inhibitor PJ-34 improves cerebromicrovascular endothelial function, neurovascular coupling responses and cognitive performance in aged mice, supporting the NAD+ depletion hypothesis of neurovascular aging.

Geroscience 2019 10 2;41(5):533-542. Epub 2019 Nov 2.

Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.

Adjustment of cerebral blood flow (CBF) to neuronal activity via neurovascular coupling (NVC) plays an important role in the maintenance of healthy cognitive function. Strong evidence demonstrates that age-related cerebromicrovascular endothelial dysfunction and consequential impairment of NVC responses contribute importantly to cognitive decline. Recent studies demonstrate that NAD availability decreases with age in the vasculature and that supplemental NAD precursors can ameliorate cerebrovascular dysfunction, rescuing NVC responses and improving cognitive performance in aged mice. The mechanisms underlying the age-related decline in [NAD] in cells of the neurovascular unit are likely multifaceted and may include increased utilization of NAD by activated poly (ADP-ribose) polymerase (PARP-1). The present study was designed to test the hypothesis that inhibition of PARP-1 activity may confer protective effects on neurovascular function in aging, similar to the recently demonstrated protective effects of treatment with the NAD+ precursor nicotinamide mononucleotide (NMN). To test this hypothesis, 24-month-old C57BL/6 mice were treated with PJ-34, a potent PARP inhibitor, for 2 weeks. NVC was assessed by measuring CBF responses (laser speckle contrast imaging) in the somatosensory whisker barrel cortex evoked by contralateral whisker stimulation. We found that NVC responses were significantly impaired in aged mice. Treatment with PJ-34 improved NVC responses by increasing endothelial NO-mediated vasodilation, which was associated with significantly improved spatial working memory. PJ-34 treatment also improved endothelium-dependent acetylcholine-induced relaxation of aorta rings. Thus, PARP-1 activation, likely by decreasing NAD availability, contributes to age-related endothelial dysfunction and neurovascular uncoupling, exacerbating cognitive decline. The cerebromicrovascular protective effects of pharmacological inhibition of PARP-1 highlight the preventive and therapeutic potential of treatments that restore NAD+ homeostasis as effective interventions in patients at risk for vascular cognitive impairment (VCI).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00101-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6885075PMC
October 2019

Assessment of age-related decline of neurovascular coupling responses by functional near-infrared spectroscopy (fNIRS) in humans.

Geroscience 2019 10 2;41(5):495-509. Epub 2019 Nov 2.

Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.

Preclinical studies provide strong evidence that age-related impairment of neurovascular coupling (NVC) plays a causal role in the pathogenesis of vascular cognitive impairment (VCI). NVC is a critical homeostatic mechanism in the brain, responsible for adjustment of local cerebral blood flow to the energetic needs of the active neuronal tissue. Recent progress in geroscience has led to the identification of critical cellular and molecular mechanisms involved in neurovascular aging, identifying these pathways as targets for intervention. In order to translate the preclinical findings to humans, there is a need to assess NVC in geriatric patients as an endpoint in clinical studies. Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that enables the investigation of local changes in cerebral blood flow, quantifying task-related changes in oxygenated and deoxygenated hemoglobin concentrations. In the present overview, the basic principles of fNIRS are introduced and the application of this technique to assess NVC in older adults with implications for the design of studies on the mechanistic underpinnings of VCI is discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00122-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6885078PMC
October 2019

Nrf2 dysfunction and impaired cellular resilience to oxidative stressors in the aged vasculature: from increased cellular senescence to the pathogenesis of age-related vascular diseases.

Geroscience 2019 12 26;41(6):727-738. Epub 2019 Oct 26.

Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, Oklahoma Center for Geroscience, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.

Aging is associated with increased oxidative stress in vascular endothelial and smooth muscle cells, which contribute to the development of a wide range of diseases affecting the circulatory system in older adults. There is growing evidence that in addition to increased production of reactive oxygen species (ROS), aging critically impairs pathways determining cellular resilience to oxidative stressors. In young organisms, the evolutionarily conserved nuclear factor-erythroid-2-related factor 2 (Nrf2)-mediated antioxidant response pathway maintains cellular reduction-oxidation homeostasis and promotes a youthful cellular phenotype by regulating the transcription of an array of cytoprotective (antioxidant, pro-survival, anti-inflammatory and macromolecular damage repair) genes. A critical mechanism by which increased ROS production and Nrf2 dysfunction promote vascular aging and exacerbate pathogenesis of age-related vascular diseases is induction of cellular senescence, an evolutionarily conserved cellular stress response mechanism. Senescent cells cease dividing and undergo distinctive phenotypic alterations, contributing to impairment of angiogenic processes, chronic sterile inflammation, remodeling of the extracellular matrix, and barrier dysfunction. Herein, we review mechanisms contributing to dysregulation of Nrf2-driven cytoprotective responses in the aged vasculature and discuss the multifaceted role of Nrf2 dysfunction in the genesis of age-related pathologies affecting the circulatory system, including its role in induction of cellular senescence. Therapeutic strategies that restore Nrf2 signaling and improve vascular resilience in aging are explored to reduce cardiovascular mortality and morbidity in older adults.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00107-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6925097PMC
December 2019

Fusogenic liposomes effectively deliver resveratrol to the cerebral microcirculation and improve endothelium-dependent neurovascular coupling responses in aged mice.

Geroscience 2019 12 25;41(6):711-725. Epub 2019 Oct 25.

Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Oklahoma Center for Geroscience, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.

Adjustment of cerebral blood flow (CBF) to the increased oxygen and nutrient demands of active brain regions via neurovascular coupling (NVC) has an essential role in maintenance of healthy cognitive function. In advanced age, cerebromicrovascular oxidative stress and endothelial dysfunction impair neurovascular coupling, contributing to age-related cognitive decline. Recently we developed a resveratrol (3,4',5-trihydroxystilbene)-containing fusogenic liposome (FL-RSV)-based molecular delivery system that can effectively target cultured cerebromicrovascular endothelial cells, attenuating age-related oxidative stress. To assess the cerebromicrovascular protective effects of FL-RSV in vivo, aged (24-month-old) C57BL/6 mice were treated with FL-RSV for four days. To demonstrate effective cellular uptake of FL-RSV, accumulation of the lipophilic tracer dyes in cells of the neurovascular unit was confirmed using two-photon imaging (through a chronic cranial window). NVC was assessed by measuring CBF responses (laser speckle contrast imaging) evoked by contralateral whisker stimulation. We found that NVC responses were significantly impaired in aged mice. Treatment with FL-RSV significantly improved NVC responses by increasing NO-mediated vasodilation. These findings are paralleled by the protective effects of FL-RSV on endothelium-dependent relaxation in the aorta. Thus, treatment with FL-RSV rescues endothelial function and NVC responses in aged mice. We propose that resveratrol containing fusogenic liposomes could also be used for combined delivery of various anti-geronic factors, including proteins, small molecules, DNA vectors and mRNAs targeting key pathways involved in microvascular aging and neurovascular dysfunction for the prevention/treatment of age-related cerebromicrovascular pathologies and development of vascular cognitive impairment (VCI) in aging.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00102-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6925096PMC
December 2019

Nicotinamide mononucleotide (NMN) supplementation promotes anti-aging miRNA expression profile in the aorta of aged mice, predicting epigenetic rejuvenation and anti-atherogenic effects.

Geroscience 2019 08 28;41(4):419-439. Epub 2019 Aug 28.

Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.

Understanding molecular mechanisms involved in vascular aging is essential to develop novel interventional strategies for treatment and prevention of age-related vascular pathologies. Recent studies provide critical evidence that vascular aging is characterized by NAD+ depletion. Importantly, in aged mice, restoration of cellular NAD+ levels by treatment with the NAD+ booster nicotinamide mononucleotide (NMN) exerts significant vasoprotective effects, improving endothelium-dependent vasodilation, attenuating oxidative stress, and rescuing age-related changes in gene expression. Strong experimental evidence shows that dysregulation of microRNAs (miRNAs) has a role in vascular aging. The present study was designed to test the hypothesis that age-related NAD+ depletion is causally linked to dysregulation of vascular miRNA expression. A corollary hypothesis is that functional vascular rejuvenation in NMN-treated aged mice is also associated with restoration of a youthful vascular miRNA expression profile. To test these hypotheses, aged (24-month-old) mice were treated with NMN for 2 weeks and miRNA signatures in the aortas were compared to those in aortas obtained from untreated young and aged control mice. We found that protective effects of NMN treatment on vascular function are associated with anti-aging changes in the miRNA expression profile in the aged mouse aorta. The predicted regulatory effects of NMN-induced differentially expressed miRNAs in aged vessels include anti-atherogenic effects and epigenetic rejuvenation. Future studies will uncover the mechanistic role of miRNA gene expression regulatory networks in the anti-aging effects of NAD+ booster treatments and determine the links between miRNAs regulated by NMN and sirtuin activators and miRNAs known to act in the conserved pathways of aging and major aging-related vascular diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00095-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6815288PMC
August 2019

Transfer of complex regional pain syndrome to mice via human autoantibodies is mediated by interleukin-1-induced mechanisms.

Proc Natl Acad Sci U S A 2019 06 10;116(26):13067-13076. Epub 2019 Jun 10.

Department of Translational Medicine, University of Liverpool, Liverpool L9 7AL, United Kingdom.

Neuroimmune interactions may contribute to severe pain and regional inflammatory and autonomic signs in complex regional pain syndrome (CRPS), a posttraumatic pain disorder. Here, we investigated peripheral and central immune mechanisms in a translational passive transfer trauma mouse model of CRPS. Small plantar skin-muscle incision was performed in female C57BL/6 mice treated daily with purified serum immunoglobulin G (IgG) from patients with longstanding CRPS or healthy volunteers followed by assessment of paw edema, hyperalgesia, inflammation, and central glial activation. CRPS IgG significantly increased and prolonged swelling and induced stable hyperalgesia of the incised paw compared with IgG from healthy controls. After a short-lasting paw inflammatory response in all groups, CRPS IgG-injected mice displayed sustained, profound microglia and astrocyte activation in the dorsal horn of the spinal cord and pain-related brain regions, indicating central sensitization. Genetic deletion of interleukin-1 (IL-1) using IL-1αβ knockout (KO) mice and perioperative IL-1 receptor type 1 (IL-1R1) blockade with the drug anakinra, but not treatment with the glucocorticoid prednisolone, prevented these changes. Anakinra treatment also reversed the established sensitization phenotype when initiated 8 days after incision. Furthermore, with the generation of an IL-1β floxed mouse line, we demonstrated that CRPS IgG-induced changes are in part mediated by microglia-derived IL-1β, suggesting that both peripheral and central inflammatory mechanisms contribute to the transferred disease phenotype. These results indicate that persistent CRPS is often contributed to by autoantibodies and highlight a potential therapeutic use for clinically licensed antagonists, such as anakinra, to prevent or treat CRPS via blocking IL-1 actions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1820168116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6600930PMC
June 2019

Cooperative 2'-O-methylation of the wobble cytidine of human elongator tRNA(CAT) by a nucleolar and a Cajal body-specific box C/D RNP.

Genes Dev 2019 07 6;33(13-14):741-746. Epub 2019 Jun 6.

Laboratoire de Biologie Moléculaire Eucaryote, UMR5099, Centre National de la Recherche Scientifique, Centre de Biologie Intégrative, Université Paul Sabatier, 31062 Toulouse Cedex 9, France.

Site-specific 2'-O-ribose methylation of mammalian rRNAs and RNA polymerase II-synthesized spliceosomal small nuclear RNAs (snRNAs) is mediated by small nucleolar and small Cajal body (CB)-specific box C/D ribonucleoprotein particles (RNPs) in the nucleolus and the nucleoplasmic CBs, respectively. Here, we demonstrate that 2'-O-methylation of the C34 wobble cytidine of human elongator tRNA(CAT) is achieved by collaboration of a nucleolar and a CB-specific box C/D RNP carrying the SNORD97 and SCARNA97 box C/D 2'-O-methylation guide RNAs. Methylation of C34 prevents site-specific cleavage of tRNA(CAT) by the stress-induced endoribonuclease angiogenin, implicating box C/D guide RNPs in controlling stress-responsive production of putative regulatory tRNA fragments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/gad.326363.119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6601510PMC
July 2019

Nicotinamide mononucleotide (NMN) treatment attenuates oxidative stress and rescues angiogenic capacity in aged cerebromicrovascular endothelial cells: a potential mechanism for the prevention of vascular cognitive impairment.

Geroscience 2019 10 29;41(5):619-630. Epub 2019 May 29.

Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.

Age-related impairment of angiogenesis likely has a critical role in cerebromicrovascular rarefaction and development of vascular cognitive impairment and dementia (VCID) in the elderly. Recently, we demonstrated that aging is associated with NAD depletion in the vasculature and that administration of NAD precursors exerts potent anti-aging vascular effects, rescuing endothelium-mediated vasodilation in the cerebral circulation and improving cerebral blood supply. The present study was designed to elucidate how treatment with nicotinamide mononucleotide (NMN), a key NAD intermediate, impacts age-related impairment of endothelial angiogenic processes. Using cerebromicrovascular endothelial cells (CMVECs) isolated from young and aged F344xBN rats, we demonstrated that compared with young cells, aged CMVECs exhibit impaired proliferation, cellular migration (measured by a wound-healing assay using electric cell-substrate impedance sensing [ECIS] technology), impaired ability to form capillary-like structures, and increased oxidative stress. NMN treatment in aged CMVECs significantly improved angiogenic processes and attenuated HO production. We also found that pre-treatment with EX-527, a pharmacological inhibitor of SIRT1, prevented NMN-mediated restoration of angiogenic processes in aged CMVECs. Collectively, we find that normal cellular NAD levels are essential for normal endothelial angiogenic processes, suggesting that age-related cellular NAD depletion and consequential SIRT1 dysregulation may be a potentially reversible mechanism underlying impaired angiogenesis and cerebromicrovascular rarefaction in aging. We recommend that pro-angiogenic effects of NAD boosters should be considered in both preclinical and clinical studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00074-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6885080PMC
October 2019

Hg and Cd binding of a bioinspired hexapeptide with two cysteine units constructed as a minimalistic metal ion sensing fluorescent probe.

Dalton Trans 2019 Jun 21;48(23):8327-8339. Epub 2019 May 21.

Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged, H-6720, Hungary.

Hg and Cd complexation of a short hexapeptide, Ac-DCSSCY-NH (DY), was studied by pH-potentiometry, UV and NMR spectroscopy and fluorimetry in aqueous solutions and the Hg-binding ability of the ligand was also described in an immobilized form, where the peptides were anchored to a hydrophilic resin. Hg was demonstrated to form a 1 : 1 complex with the ligand even at pH = 2.0 while Cd coordination by the peptide takes place only above pH ∼ 3.5. Both metal ions form bis-ligand complexes by the coordination of four Cys-thiolates at ligand excess above pH ∼ 5.5 (Cd) and 7.0 (Hg). Fluorescence studies demonstrated a Hg induced concentration-dependent quenching of the Tyr fluorescence until a 1 : 1 Hg : DY ratio. The fluorescence emission intensity decreases linearly with the increasing Hg concentration in a range of over two orders of magnitude. The fact that this occurs even in the presence of 1.0 eq. of Cd per ligand reflects a complete displacement of the latter metal ion by Hg from its peptide-bound form. The immobilized peptide was also shown to bind Hg very efficiently even from samples at pH = 2.0. However, the existence of lower affinity binding sites was also demonstrated by binding of more than 1.0 eq. of Hg per immobilized DY molecule under Hg-excess conditions. Experiments performed with a mixture of four metal ions, Hg, Cd, Zn and Ni, indicate that this molecular probe may potentially be used in Hg-sensing systems under acidic conditions for the measurement of μM range concentrations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9dt01141bDOI Listing
June 2019

Central IGF-1 protects against features of cognitive and sensorimotor decline with aging in male mice.

Geroscience 2019 04 10;41(2):185-208. Epub 2019 May 10.

Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer Bldg, Rm 236, 1300 Morris Park Avenue, Bronx, NY, 10461, USA.

Disruptions in growth hormone/insulin-like growth factor-1 (GH/IGF-1) signaling have been linked to improved longevity in mice and humans. Nevertheless, while IGF-1 levels are associated with increased cancer risk, they have been paradoxically implicated with protection from other age-related conditions, particularly in the brain, suggesting that strategies aimed at selectively increasing central IGF-1 action may have favorable effects on aging. To test this hypothesis, we generated inducible, brain-specific (TRE-IGF-1 × Camk2a-tTA) IGF-1 (bIGF-1) overexpression mice and studied effects on healthspan. Doxycycline was removed from the diet at 12 weeks old to permit post-development brain IGF-1 overexpression, and animals were monitored up to 24 months. Brain IGF-1 levels were increased approximately twofold in bIGF-1 mice, along with greater brain weights, volume, and myelin density (P < 0.05). Age-related changes in rotarod performance, exercise capacity, depressive-like behavior, and hippocampal gliosis were all attenuated specifically in bIGF-1 male mice (P < 0.05). However, chronic brain IGF-1 failed to prevent declines in cognitive function or neurovascular coupling. Therefore, we performed a short-term intranasal (IN) treatment of either IGF-1 or saline in 24-month-old male C57BL/6 mice and found that IN IGF-1 treatment tended to reduce depressive (P = 0.09) and anxiety-like behavior (P = 0.08) and improve motor coordination (P = 0.07) and unlike transgenic mice improved motor learning (P < 0.05) and visuospatial and working memory (P < 0.05). These data highlight important sex differences in how brain IGF-1 action impacts healthspan and suggest that translational approaches that target IGF-1 centrally can restore cognitive function, a possibility that should be explored as a strategy to combat age-related cognitive decline.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00065-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544744PMC
April 2019

Age-related decline in peripheral vascular health predicts cognitive impairment.

Geroscience 2019 04 27;41(2):125-136. Epub 2019 Apr 27.

Translational Geroscience Laboratory, Reynolds Oklahoma Center on Aging/Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, 975 NE 10th street, BRC 1311, Oklahoma City, OK, 73104, USA.

Preclinical studies demonstrate that generalized endothelial cell dysfunction and microvascular impairment are potentially reversible causes of age-related vascular cognitive impairment and dementia (VCID). The present study was designed to test the hypothesis that severity of age-related macro- and microvascular dysfunction measured in the peripheral circulation is an independent predictor of cognitive performance in older adults. In this study, we enrolled 63 healthy individuals into young (< 45 years old) and aged (> 65 years old) groups. We used principal component analysis (PCA) to construct a comprehensive peripheral vascular health index (VHI) encompassing peripheral microvascular reactivity, arterial endothelial function, and vascular stiffness, as a marker of aging-induced generalized vascular dysfunction. Peripheral macrovascular and microvascular endothelial function were assessed using flow-mediated dilation (FMD) and laser speckle contrast imaging tests. Pulse waveform analysis was used to evaluate the augmentation index (AIx), a measure of arterial stiffness. Cognitive function was measured using a panel of CANTAB cognitive tests, and PCA was then applied to generate a cognitive impairment index (CII) for each participant. Aged subjects exhibited significantly impaired macrovascular endothelial function (FMD, 5.6 ± 0.7% vs. 8.3 ± 0.6% in young, p = 0.0061), increased arterial stiffness (AIx 29.3 ± 1.8% vs 4.5 ± 2.6% in young, p < 0.0001), and microvascular dysfunction (2.8 ± 0.2 vs 3.4 ± 0.1-fold change of perfusion in young, p = 0.032). VHI showed a significant negative correlation with age (r = - 0.54, p < 0.0001) and CII significantly correlated with age (r = 0.79, p < 0.0001). VHI significantly correlated with the CII (r = - 0.46, p = 0.0003). A decline in peripheral vascular health may reflect generalized vascular dysfunction and predict cognitive impairment in older adults.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11357-019-00063-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544701PMC
April 2019