Publications by authors named "Leah P Shriver"

36 Publications

Longitudinal Metabolomics of Human Plasma Reveals Robust Prognostic Markers of COVID-19 Disease Severity.

medRxiv 2021 Feb 8. Epub 2021 Feb 8.

There is an urgent need to identify which COVID-19 patients will develop life-threatening illness so that scarce medical resources can be optimally allocated and rapid treatment can be administered early in the disease course, when clinical management is most effective. To aid in the prognostic classification of disease severity, we performed untargeted metabolomics profiling of 341 patients with plasma samples collected at six longitudinal time points. Using the temporal metabolic profiles and machine learning, we then built a predictive model of disease severity. We determined that the levels of 25 metabolites measured at the time of hospital admission successfully predict future disease severity. Through analysis of longitudinal samples, we confirmed that these prognostic markers are directly related to disease progression and that their levels are restored to baseline upon disease recovery. Finally, we validated that these metabolites are also altered in a hamster model of COVID-19. Our results indicate that metabolic changes associated with COVID-19 severity can be effectively used to stratify patients and inform resource allocation during the pandemic.
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http://dx.doi.org/10.1101/2021.02.05.21251173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7872388PMC
February 2021

Synthesis, characterization, in vitro SAR study, and preliminary in vivo toxicity evaluation of naphthylmethyl substituted bis-imidazolium salts.

Bioorg Med Chem 2021 Jan 28;30:115893. Epub 2020 Nov 28.

Department of Chemistry, The University of Akron, Akron, OH 44325-3601, USA. Electronic address:

A series of novel bis-imidazolium salts was synthesized, characterized, and evaluated in vitro against a panel of non-small cell lung cancer (NSCLC) cells. Two imidazolium cores were connected with alkyl chains of varying lengths to develop a structure activity relationship (SAR). Increasing the length of the connecting alkyl chain was shown to correlate to an increase in the anti-proliferative activity. The National Cancer Institute's NCI-60 human tumor cell line screen confirmed this trend. The compound containing a decyl linker chain, 10, was chosen for further in vivo toxicity studies with C578BL/6 mice. The compound was well tolerated by the mice and all of the animals survived and gained weight over the course of the study.
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http://dx.doi.org/10.1016/j.bmc.2020.115893DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7903221PMC
January 2021

Softening of the chronic hemi-section spinal cord injury scar parallels dysregulation of cellular and extracellular matrix content.

J Mech Behav Biomed Mater 2020 10 30;110:103953. Epub 2020 Jun 30.

Department of Biomedical Engineering, The University of Akron, Akron, OH, 44325, USA; Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, OH, 44325, USA. Electronic address:

Regeneration following spinal cord injury (SCI) is challenging in part due to the modified tissue composition and organization of the resulting glial and fibrotic scar regions. Inhibitory cell types and biochemical cues present in the scar have received attention as therapeutic targets to promote regeneration. However, altered Young's modulus of the scar as a readout for potential impeding factors for regeneration are not as well-defined, especially in vivo. Although the decreased Young's modulus of surrounding tissue at acute stages post-injury is known, the causation and outcomes at chronic time points remain largely understudied and controversial, which motivates this work. This study assessed the glial and fibrotic scar tissue's Young's modulus and composition (scar morphometry, cell identity, extracellular matrix (ECM) makeup) that contribute to the tissue's stiffness. The spatial Young's modulus of a chronic (~18-wks, post-injury) hemi-section, including the glial and fibrotic regions, were significantly less than naïve tissue (~200 Pa; p < 0.0001). The chronic scar contained cystic cavities dispersed in areas of dense nuclei packing. Abundant CNS cell types such as astrocytes, oligodendrocytes, and neurons were dysregulated in the scar, while epithelial markers such as vimentin were upregulated. The key ECM components in the CNS, namely sulfated proteoglycans (sPGs), were significantly downregulated following injury with concomitant upregulation of unsulfated glycosaminoglycans (GAGs) and hyaluronic acid (HA), likely altering the foundational ECM network that contributes to tissue stiffness. Our results reveal the Young's modulus of the chronic SCI scar as well as quantification of contributing elastic components that can provide a foundation for future study into their role in tissue repair and regeneration.
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http://dx.doi.org/10.1016/j.jmbbm.2020.103953DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7509206PMC
October 2020

Metabolomic and Signaling Programs Induced by Immobilized versus Soluble IFN γ in Neural Stem Cells.

Bioconjug Chem 2020 09 21;31(9):2125-2135. Epub 2020 Aug 21.

Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States.

Neural stem cells (NSCs) provide a strategy to replace damaged neurons following traumatic central nervous system injuries. A major hurdle to translation of this therapy is that direct application of NSCs to CNS injury does not support sufficient neurogenesis due to lack of proper cues. To provide prolonged spatial cues to NSCs IFN-γ was immobilized to biomimetic hydrogel substrate to supply physical and biochemical signals to instruct the encapsulated NSCs to be neurogenic. However, the immobilization of factors, including IFN-γ, versus soluble delivery of the same factor, has been incompletely characterized especially with respect to activation of signaling and metabolism in cells over longer time points. In this study, protein and metabolite changes in NSCs induced by immobilized versus soluble IFN-γ at 7 days were evaluated. Soluble IFN-γ, refreshed daily over 7 days, elicited stronger responses in NSCs compared to immobilized IFN-γ, indicating that immobilization may not sustain signaling or has altered ligand/receptor interaction and integrity. However, both IFN-γ delivery types supported increased βIII tubulin expression in parallel with canonical and noncanonical receptor-signaling compared to no IFN-γ. Global metabolomics and pathway analysis revealed that soluble and immobilized IFN-γ altered metabolic pathway activities including energy, lipid, and amino acid synthesis, with soluble IFN-γ having the greatest metabolic impact overall. Finally, soluble and immobilized IFN-γ support mitochondrial voltage-dependent anion channel (VDAC) expression that correlates to differentiated NSCs. This work utilizes new methods to evaluate cell responses to protein delivery and provides insight into mode of action that can be harnessed to improve regenerative medicine-based strategies.
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http://dx.doi.org/10.1021/acs.bioconjchem.0c00338DOI Listing
September 2020

Targeted Delivery of Anti-inflammatory and Imaging Agents to Microglial Cells with Polymeric Nanoparticles.

Mol Pharm 2020 06 28;17(6):1816-1826. Epub 2020 Apr 28.

Department of Chemistry, Knight Chemical Laboratories, University of Akron, Akron, Ohio 44325, United States.

Insult to the central nervous system (CNS) results in an early inflammatory response, which can be exploited as an initial indicator of neurological dysfunction. Nanoparticle drug delivery systems provide a mechanism to increase the uptake of drugs into specific cell types in the CNS such as microglia, the resident macrophage responsible for innate immune response. In this study, we developed two nanoparticle-based carriers as potential theranostic systems for drug delivery to microglial cells. Poly(lactic--glycolic) acid (PLGA)- and l-tyrosine polyphosphate (LTP)-based nanoparticles were synthesized to encapsulate the magnetic resonance imaging (MRI) contrast agent, gadolinium-diethylenetriaminepentaacetic acid (Gd[DTPA]), or the anti-inflammatory drug, rolipram. Robust uptake of both polymer formulations by microglial cells was observed with no evidence of toxicity. In mixed glial cultures, we observed a preferential internalization of nanoparticles by microglia compared to that of astrocytes. Moreover, exposure of our nanoparticles to microglial cells did not induce the release of the proinflammatory cytokines, tumor necrosis factor α (TNF-α), interleukin-1 β (IL-1β), or interleukin-6 (IL-6). These studies provide a foundation for the development of LTP nanoparticles as a platform for the delivery of imaging agents and drugs to the sites of neuroinflammation.
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http://dx.doi.org/10.1021/acs.molpharmaceut.9b00489DOI Listing
June 2020

Efficient synthesis of NIR emitting bis[2-(2'-hydroxylphenyl)benzoxazole] derivative and its potential for imaging applications.

Bioorg Chem 2020 03 15;96:103585. Epub 2020 Jan 15.

Department of Chemistry, The University of Akron, Akron, OH 44325, USA; Maurice Morton Institute of Polymer Science, The University of Akron, Akron, OH 44325, USA. Electronic address:

Unassymetric bis[2-(2'-hydroxyphenylbenzoxole)] bis(HBO) derivatives with a DPA functionality for zinc binding have been developed with an efficient synthetic route, using the retrosynthetic analysis. Comparison of bis(HBO) derivatives with different substitution patterns allows us to verify and optimize their unique fluorescence properties. Upon binding zinc cation, bis(HBO) derivatives give a large fluorescence turn-on in both visible (λ ≈ 536 nm) and near-infrared (NIR) window (λ ≈ 746 nm). The probes are readily excitable by a 488 nm laser, making this series of compounds a suitable imaging tool for in vitro and in vivo study on a confocal microscope. The application of zinc binding-induced fluorescence turn-on is successfully demonstrated in cellular environments and thrombus imaging.
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http://dx.doi.org/10.1016/j.bioorg.2020.103585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7159060PMC
March 2020

Fluorinated Methacrylamide Chitosan Hydrogel Dressings Improve Regenerated Wound Tissue Quality in Diabetic Wound Healing.

Adv Wound Care (New Rochelle) 2019 Aug 25;8(8):374-385. Epub 2019 Jul 25.

Department of Chemical and Biomolecular Engineering, University of Akron, Akron, Ohio.

Oxygen therapy has shown promising results for treating diabetic wounds. However, clinically used oxygen therapies are cumbersome and expensive. Thus, there is a need to develop a localized oxygenating treatment that is easy to use and inexpensive. In this study, we tested a previously developed hydrogel sheet wound dressing based on fluorinated methacrylamide chitosan (MACF) for enhanced oxygenation and compared it with a commercial sheet hydrogel dressing, AquaDerm™, and no treatment controls in a splinted transgenic diabetic mouse wound model. AquaDerm exhibited poor wound closure response compared with the MACF oxygenating hydrogel sheet dressing (MACF+O) and no treatment. Histological analysis revealed enhanced collagen synthesis and neovascularization upon MACF+O treatment as indicated by higher collagen content and number of blood vessels/capillaries compared with AquaDerm and no treatment. MACF+O also improved wound collagen fiber alignment, thus demonstrating improved skin tissue maturation. Nuclear magnetic resonance spectroscopy-based biodistribution analysis revealed that the degradation products of the MACF-based dressing did not accumulate in lung, liver, and kidney tissues of the treated animals after 14 days of treatment. This study presents the first application of a unique oxygenating biomaterial (MACF) made into a moist hydrogel wound dressing for treating diabetic wounds. The results of this study confirm the benefits of this novel biomaterial approach for improving regenerated tissue structure in diabetic wound healing.
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http://dx.doi.org/10.1089/wound.2018.0887DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6657299PMC
August 2019

A Fluorescent Flavonoid for Lysosome Imaging: the Effect of Substituents on Selectivity and Optical Properties.

J Fluoresc 2019 May 6;29(3):599-607. Epub 2019 Apr 6.

Department of Chemistry, University of Akron, Akron, OH, 44325, USA.

Lysosome selective bright orange-red emitting flavonoid (2) was synthesized by attaching a strong donor (NPh) group into flavonoid skeleton. As a result of efficient intra molecular charge transfer due to the strong donor group, a significant bathochromic shift was observed from the emission of 2b (with a -NPh group, λ ≈ 590 nm), in comparison that of 1b (with a -NMe group, λ ≈ 519 nm). The role of the substituent effect towards ICT was further studied by low temperature spectral analysis. Fluorescence spectra at low temperature confirmed that large Stokes shift for probe 2 (Δλ ≈ 150 nm) was due to strong ICT. Probe 2b exhibited exceptional selectivity towards cellular lysosomes in live cells studies thus generating bright orange-red emission upon localization. Intra-cellular pH analysis results confirmed that probe 2b did not participate in the elevation of lysosomal pH upon staining with different probe concentrations (0.5 μM - 2.0 μM) which is a potential advantage compared to acidotropic commercial LysoTracker® probes. This study further illustrated that the substituents in probe 2 play a significant role towards probe's organelle selectivity since probe 2a (R = OH) did not show any lysosomal localization compared with 2b. In addition, the calculated cytotoxicity data further revealed that this new probe design is highly biocompatible (LC > 50 μM) and suitable for long term imaging. Graphical Abstract.
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http://dx.doi.org/10.1007/s10895-019-02371-7DOI Listing
May 2019

Fluorinated methacrylamide chitosan hydrogel dressings enhance healing in an acute porcine wound model.

PLoS One 2018 5;13(9):e0203371. Epub 2018 Sep 5.

Department of Chemical and Biomolecular Engineering, University of Akron, Akron, Ohio, United States of America.

Wound healing involves multiple interrelated processes required to lead to successful healing outcomes. Phagocytosis, inflammation, cell proliferation, angiogenesis, energy production, and collagen synthesis are all directly or indirectly dependent on oxygen. Along with other critical factors, such as nutrition and comorbidities, availability of oxygen is a key determinant of healing success. Previously, we have presented a novel oxygenated hydrogel material that can be made into dressings for continuous localized oxygen delivery to wounds. In this study, an acute porcine wound model was used to test the healing benefits of these oxygenated MACF (MACF + O2) hydrogel dressings compared to controls, which included commercial Derma-GelTM hydrogel dressings. Wound closure and histological analyses were performed to assess re-epithelialization, collagen synthesis, angiogenesis, and keratinocyte maturation. Results from these assays revealed that wounds treated with MACF + O2 hydrogel dressings closed faster as compared to Derma-Gel (p<0.05). Targeted metabolomics via liquid chromatography separation and mass spectrometric detection (LC-MS/MS) and a biochemical assay determined the concentration of hydroxyproline in wound samples at days 14 and 21, showing that MACF + O2 hydrogel dressings improved wound healing via an upregulated collagen synthesis pathway as compared to Derma-Gel (p<0.05). Histological evidence showed that MACF + O2 hydrogel dressings improve new blood vessel formation and keratinocyte maturation over all other treatments.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0203371PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6124756PMC
February 2019

A fluorescent flavonoid for lysosome detection in live cells under "wash free" conditions.

J Mater Chem B 2018 Aug 24;6(31):5050-5058. Epub 2018 Jul 24.

Department of Chemistry, University of Akron, Akron, Ohio 44325, USA.

Lysosomes are vital organelles in living cells, which have acidic environments (pH 4.0-5.0) where macrobiomolecules and malfunctioning organelles are broken down into monomers by hydrolase activity. The majority of the currently reported fluorescent probes for detecting lysosomes suffer from small Stokes shifts (Δλ < 20 nm) and higher cytotoxicity due to an "alkalinizing effect". An interesting flavonoid-based lysosome probe is synthesized by introducing a morpholine moiety onto the flavonoid skeleton. This new probe has shown excellent selectivity to detect lysosomes in MO3.13 oligodendrocytes and normal human lung fibroblast cell lines. Probes 1a and 1b have shown excellent fluorescence quantum yield (φ up to 0.43 in non-aqueous solvents) and large Stokes shifts (120-150 nm). These new fluorescent probes also exhibit a large quantum yield difference from an aqueous to organic environment, making them potentially useful as "wash-free" stains for visualizing lysosomes. Cell viability evaluation of these probes shows excellent biocompatibility with the median lethal concentration being LC50 ≈ 50 μM.
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http://dx.doi.org/10.1039/c8tb00325dDOI Listing
August 2018

NIR-emitting benzothiazolium cyanines with an enhanced stokes shift for mitochondria imaging in live cells.

Org Biomol Chem 2018 05;16(18):3382-3388

Department of Chemistry, University of Akron, Akron, Ohio 44325, USA.

A series of benzothiazolium-based hemicyanines (3a-3f) have been synthesized. Evaluation of their photophysical properties shows that they exhibit improved photophysical characteristics. In comparison with the available commercial MitoTrackers, the new probes revealed an enhanced Stokes shift (Δλ ∼ 80 nm) and minimized aggregation for increased sensitivity. The synthesized probes are found to exhibit excellent selectivity for mitochondrial staining in an oligodendrocyte cell line. Probes show almost no fluorescence in aqueous environments, while the fluorescence is increased by ∼10-fold in organic solvents, making it possible for mitochondrial imaging without the need for post-staining washing. Since the absorption peaks of probes are close to the laser wavelengths of 561 and 640 nm on a commercial confocal microscope, e.g.3a exhibits λabs ∼ 620 nm and λem ∼ 702 nm, they could be useful probes for mitochondrial tracking in live cells.
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http://dx.doi.org/10.1039/c8ob00327kDOI Listing
May 2018

Fluorescent flavonoids for endoplasmic reticulum cell imaging.

J Mater Chem B 2016 Dec 23;4(48):7902-7908. Epub 2016 Nov 23.

Department of Chemistry, University of Akron, Akron, Ohio 44325, USA.

Visualization of subcellular organelles in vivo is critical for basic biomedical research and clinical applications. Two new flavonoids with an amide substituent were synthesized and characterized. The flavonoids were nearly non-fluorescent in aqueous environment, but exhibited two emission peaks (one at 495-536 nm and the other at 570-587 nm) in organic solvents, which were assigned to the excited normal (N) and tautomer (T) emission. When the dyes were examined on oligodendrocyte cells, they were found to selectively accumulate in the endoplasmic reticulum (ER), a eukaryotic organelle involved in lipid and protein synthesis, giving fluorescence turn-on. The ER-selective flavonoids could be a valuable tool due to its low molecular mass (<500), large Stokes' shift, low toxicity, and biocompatibility.
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http://dx.doi.org/10.1039/c6tb02456dDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5472391PMC
December 2016

Cuprizone Intoxication Induces Cell Intrinsic Alterations in Oligodendrocyte Metabolism Independent of Copper Chelation.

Biochemistry 2017 03 28;56(10):1518-1528. Epub 2017 Feb 28.

Department of Chemistry, University of Akron , Akron, Ohio 44325, United States.

Cuprizone intoxication is a common animal model used to test myelin regenerative therapies for the treatment of diseases such as multiple sclerosis. Mice fed this copper chelator develop reversible, region-specific oligodendrocyte loss and demyelination. While the cellular changes influencing the demyelinating process have been explored in this model, there is no consensus about the biochemical mechanisms of toxicity in oligodendrocytes and about whether this damage arises from the chelation of copper in vivo. Here we have identified an oligodendroglial cell line that displays sensitivity to cuprizone toxicity and performed global metabolomic profiling to determine biochemical pathways altered by this treatment. We link these changes with alterations in brain metabolism in mice fed cuprizone for 2 and 6 weeks. We find that cuprizone induces widespread changes in one-carbon and amino acid metabolism as well as alterations in small molecules that are important for energy generation. We used mass spectrometry to examine chemical interactions that are important for copper chelation and toxicity. Our results indicate that cuprizone induces global perturbations in cellular metabolism that may be independent of its copper chelating ability and potentially related to its interactions with pyridoxal 5'-phosphate, a coenzyme essential for amino acid metabolism.
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http://dx.doi.org/10.1021/acs.biochem.6b01072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6145805PMC
March 2017

Synthesis, characterization, in vitro SAR and in vivo evaluation of N,N'bisnaphthylmethyl 2-alkyl substituted imidazolium salts against NSCLC.

Bioorg Med Chem Lett 2017 02 16;27(4):764-775. Epub 2017 Jan 16.

Department of Chemistry, University of Akron, Akron, OH 44325, United States. Electronic address:

Alkyl- and N,N'-bisnaphthyl-substituted imidazolium salts were tested in vitro for their anti-cancer activity against four non-small cell lung cancer cell lines (NCI-H460, NCI-H1975, HCC827, A549). All compounds had potent anticancer activity with 2 having IC values in the nanomolar range for three of the four cell lines, a 17-fold increase in activity against NCI-H1975 cells when compared to cisplatin. Compounds 1-4 also showed high anti-cancer activity against nine NSCLC cell lines in the NCI-60 human tumor cell line screen. In vitro studies performed using the Annexin V and JC-1 assays suggested that NCI-H460 cells treated with 2 undergo an apoptotic cell death pathway and that mitochondria could be the cellular target of 2 with the mechanism of action possibly related to a disruption of the mitochondrial membrane potential. The water solubilities of 1-4 was over 4.4mg/mL using 2-hydroxypropyl-β-cyclodextrin as a chemical excipient, thereby providing sufficient solubility for systemic administration.
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http://dx.doi.org/10.1016/j.bmcl.2017.01.035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5575737PMC
February 2017

Synthesis, anti-proliferative activity, SAR study, and preliminary in vivo toxicity study of substituted N,N'-bis(arylmethyl)benzimidazolium salts against a panel of non-small cell lung cancer cell lines.

Bioorg Med Chem 2017 01 5;25(1):421-439. Epub 2016 Nov 5.

Department of Chemistry, The University of Akron, Akron, OH 44325-3601, USA. Electronic address:

A series of N,N'-bis(arylmethyl)benzimidazolium salts have been synthesized and evaluated for their in vitro anti-cancer activity against select non-small cell lung cancer cell lines to create a structure activity relationship profile. The results indicate that hydrophobic substituents on the salts increase the overall anti-proliferative activity. Our data confirms that naphthylmethyl substituents at the nitrogen atoms (N(N)) and highly lipophilic substituents at the carbon atoms (C and C(C)) can generate benzimidazolium salts with anti-proliferative activity that is comparable to that of cisplatin. The National Cancer Institute's Developmental Therapeutics Program tested 1, 3-5, 10, 11, 13-18, 20-25, and 28-30 in their 60 human tumor cell line screen. Results were supportive of data observed in our lab. Compounds with hydrophobic substituents have higher anti-cancer activity than compounds with hydrophilic substituents.
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http://dx.doi.org/10.1016/j.bmc.2016.11.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5164943PMC
January 2017

Spinal Cord Transcriptomic and Metabolomic Analysis after Excitotoxic Injection Injury Model of Syringomyelia.

J Neurotrauma 2017 02 13;34(3):720-733. Epub 2016 Oct 13.

1 Department of Chemical and Biomolecular Engineering, University of Akron , Akron, Ohio.

Syringomyelia is a condition of the spinal cord in which a syrinx, or fluid-filled cavity, forms from trauma, malformation, or general disorder. Previous work has shown that in noncanalicular syringomyelia irregular flow and pressure conditions enhance the volumetric growth of syrinxes. A better understanding of the underlying molecular pathways associated with syrinx formation will unveil targets for treatments and possibly prevention of syringomyelia in the future. In this study, we performed an established surgical induction of a syrinx using quisqualic acid and kaolin injections in rats to characterize the injury at the molecular level by RNA sequencing and metabolomics techniques at three and six weeks post-injury. Syrinxes averaging nearly 10 mm in length formed in the rats' spinal cords; however, smaller syrinxes were also detected in saline injected surgical shams, complicating interpretation of results. Our current results indicate a robust immune response coupled with overall decreases in neuronal signal transmission of syrinx containing animals compared with controls. Although transcriptional changes indicated gliosis and loss of neurons, no neuropathic pain was detected by von Frey allodynia testing. Unique transporters were revealed to be highly dysregulated, including significant increases in betaine/glycine transporter (BGT-1), K+/Cl- co-transporter (KCC4), and aquaporin 1 (AQP1), along with the upregulation of small molecule osmolytes taurine and betaine. The identified metabolites are of particular interest because of their involvement in osmotic homeostasis and need to be investigated further for their specific involvement in trauma-induced syrinxes.
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http://dx.doi.org/10.1089/neu.2015.4341DOI Listing
February 2017

Longitudinal Metabolite Profiling of Cerebrospinal Fluid in Normal Pressure Hydrocephalus Links Brain Metabolism with Exercise-Induced VEGF Production and Clinical Outcome.

Neurochem Res 2016 Jul 15;41(7):1713-22. Epub 2016 Apr 15.

Departments of Chemistry and Biology, University of Akron, Akron, OH, 44325, USA.

Idiopathic normal pressure hydrocephalus is a neurological disease caused by abnormal cerebrospinal fluid flow and presents with symptoms such as dementia. Current therapy involves the removal of excess cerebrospinal fluid by shunting. Not all patients respond to this therapy and biomarkers are needed that could facilitate the characterization of patients likely to benefit from this treatment. Here, we measure brain metabolism in normal pressure hydrocephalus patients by performing a novel longitudinal metabolomic profiling study of cerebrospinal fluid. We find that the levels of brain metabolites correlate with clinical parameters, the amount of vascular endothelial growth factor in the cerebrospinal fluid, and environmental stimuli such as exercise. Metabolomic analysis of normal pressure hydrocephalus patients provides insight into changes in brain metabolism that accompany cerebrospinal fluid disorders and may facilitate the development of new biomarkers for this condition.
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http://dx.doi.org/10.1007/s11064-016-1887-zDOI Listing
July 2016

Fluorinated methacrylamide chitosan hydrogels enhance collagen synthesis in wound healing through increased oxygen availability.

Acta Biomater 2016 05 18;36:164-74. Epub 2016 Mar 18.

Department of Chemical and Biomolecular Engineering, University of Akron, OH 44325, USA. Electronic address:

Unlabelled: In this study, methacrylamide chitosan modified with perfluorocarbon chains (MACF) is used as the base material to construct hydrogel dressings for treating dermal wounds. MACF hydrogels saturated with oxygen (+O2) are examined for their ability to deliver and sustain oxygen, degrade in a biological environment, and promote wound healing in an animal model. The emerging technique of metabolomics is used to understand how MACF+O2 hydrogel dressings improve wound healing. Results indicate that MACF treatment facilitates oxygen transport rate that is two orders of magnitude greater than base MAC hydrogels. MACF hydrogel dressings are next tested in an in vivo splinted rat excisional wound healing model. Histological analysis reveals that MACF+O2 dressings improve re-epithelialization (p<0.0001) and synthesis of collagen over controls (p<0.01). Analysis of endogenous metabolites in the wounds using global metabolomics demonstrates that MACF+O2 dressings promotes a regenerative metabolic process directed toward hydroxyproline and collagen synthesis, with confirmation of metabolite levels within this pathway. The results of this study confirm that increased oxygen delivery through the application of MACF+O2 hydrogels enhances wound healing and metabolomics analyses provides a powerful tool to assess wound healing physiology.

Statement Of Significance: This work presents the first application of a novel class of oxygen delivering biomaterials (methacrylamide chitosan modified with perfluorocarbon chains (MACF)) as a hydrogel wound dressing. This manuscript also contains strong focus on the biochemical benefits of MACF dressings on underlying mechanisms vital to successful wound healing. In this vein, this manuscript presents the application of applied metabolomics (tandem mass spectroscopy) to uncover biomaterial interactions with wound healing mechanisms. We believe the approaches described in this manuscript will be of great interest to biomedical scientists and particularly to researchers studying wound healing, metabolomics, applied biomaterials and regenerative medicine.
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http://dx.doi.org/10.1016/j.actbio.2016.03.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4846531PMC
May 2016

Exercise-induced changes of cerebrospinal fluid vascular endothelial growth factor in adult chronic hydrocephalus patients.

J Clin Neurosci 2016 Feb 21;24:52-6. Epub 2015 Oct 21.

Department of Neurological Surgery, Neurological Institute, Cleveland Clinic, S-60, 9500 Euclid Avenue, Cleveland, OH, USA; Department of Neurosurgery, Phipps 126, 600 North Wolfe Street, Johns Hopkins Medical Hospital, Baltimore, MD 21287, USA. Electronic address:

Vascular endothelial growth factor (VEGF) is a growth factor demonstrated to be a key factor in cerebral angiogenesis and neurogenesis. It has been considered a critical component in hippocampus neurogenesis and memory formation and has been observed to increase in the rat hippocampus after exercise. We previously found increased VEGF levels in experimental chronic hydrocephalus in several brain areas and cerebrospinal fluid (CSF), suggesting a role in the adaption to chronic hypoxia. Here we investigate the ability of moderate exercise to increase CSF-VEGF levels in adult chronic hydrocephalus patients. Lumbar CSF samples were collected from 17 normal pressure hydrocephalus patients. During CSF collection, 11 patients (exercise group) underwent a standard in-room occupational therapy session; six patients (no-exercise group) did not undergo a physical therapy session. CSF-VEGF levels were evaluated for increase related to exercise and the clinical response to CSF drainage. CSF-VEGF levels in the exercise group demonstrated significant increases 1-3 hours post-exercise compared with the levels 1-2 hours pre-exercise (p=0.04), and also showed significantly higher levels than the no-exercise groups (p=0.03). The post-exercise CSF-VEGF level in the group that did not clinically improve was significantly higher than both their own pre-exercise level (p=0.02) and that seen in the clinically improving group (p=0.05) after exercise. We conclude that CSF-VEGF levels can increase after moderate exercise even in elderly hydrocephalus patients. This suggests that a potential benefit of exercise, especially in CSF drainage non-improved patients, may exist via a central VEGF mechanism.
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http://dx.doi.org/10.1016/j.jocn.2015.08.019DOI Listing
February 2016

Alterations in Spinal Cord Metabolism during Treatment of Neuropathic Pain.

J Neuroimmune Pharmacol 2015 Sep 2;10(3):396-401. Epub 2015 Aug 2.

Scripps Center for Metabolomics and Mass Spectrometry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.

Therapeutic options for neuropathic pain have improved over the last 20 years yet still only provide partial relief with numerous side effects. Recently, metabolomics revealed that the concentration of the endogenous metabolite N,N-dimethylsphingosine (DMS) is increased in the spinal cord in a model of neuropathic pain. Additionally, it was shown that introduction of DMS to the central nervous system (CNS) resulted in mechanical allodynia. Here, we have examined two compounds; pregabalin (Lyrica®), a drug used to treat neuropathic pain, and N-oleoylethanolamine (NOE), an endogenous endocannabinoid-like compound that is known to affect multiple lipid pathways. We found that the concentration of DMS in the spinal cord was not significantly altered upon pregabalin treatment of rats suffering from neuropathic pain. We further explored whether modulating lipid metabolism may impact neuropathic pain by testing NOE as a potential novel therapeutic.
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http://dx.doi.org/10.1007/s11481-015-9624-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4548716PMC
September 2015

Dimethyl fumarate modulates antioxidant and lipid metabolism in oligodendrocytes.

Redox Biol 2015 Aug 29;5:169-175. Epub 2015 Apr 29.

Department of Chemistry, University of Akron, Akron, OH 44325, USA; Department of Biology, University of Akron, Akron, OH 44325, USA. Electronic address:

Oxidative stress contributes to pathology associated with inflammatory brain disorders and therapies that upregulate antioxidant pathways may be neuroprotective in diseases such as multiple sclerosis. Dimethyl fumarate, a small molecule therapeutic for multiple sclerosis, activates cellular antioxidant signaling pathways and may promote myelin preservation. However, it is still unclear what mechanisms may underlie this neuroprotection and whether dimethyl fumarate affects oligodendrocyte responses to oxidative stress. Here, we examine metabolic alterations in oligodendrocytes treated with dimethyl fumarate by using a global metabolomic platform that employs both hydrophilic interaction liquid chromatography-mass spectrometry and shotgun lipidomics. Prolonged treatment of oligodendrocytes with dimethyl fumarate induces changes in citric acid cycle intermediates, glutathione, and lipids, indicating that this compound can directly impact oligodendrocyte metabolism. These metabolic alterations are also associated with protection from oxidant challenge. This study provides insight into the mechanisms by which dimethyl fumarate could preserve myelin integrity in patients with multiple sclerosis.
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http://dx.doi.org/10.1016/j.redox.2015.04.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4427661PMC
August 2015

Lysine addressability and mammalian cell interactions of bacteriophage λ procapsids.

Biomacromolecules 2013 Dec 26;14(12):4169-76. Epub 2013 Nov 26.

Departments of Chemistry and Biology, Carthage College , Kenosha, Wisconsin, United States.

Chemically or genetically modified virus particles, termed viral nanoparticles (VNPs), are being explored in applications such as drug delivery, vaccine development, and materials science. Each virus platform has inherent properties and advantages based on its structure, molecular composition, and biomolecular interactions. Bacteriophage λ was studied for its lysine addressability, stability, cellular uptake, and the ability to modify its cellular uptake. λ procapsids could be labeled primarily at a single residue on the gpE capsid protein as determined by tandem mass spectrometry, providing a unique attachment site for further capsid modification. Bioconjugation of transferrin to the procapsids mediated specific interaction with transferrin receptor-expressing cells. These studies demonstrate the utility of bacteriophage λ procapsids and their potential use as targeted drug delivery vehicles.
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http://dx.doi.org/10.1021/bm401577fDOI Listing
December 2013

Localization of gadolinium-loaded CPMV to sites of inflammation during central nervous system autoimmunity.

J Mater Chem B 2013 Oct 7;1(39):5256-5263. Epub 2013 Jun 7.

Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, USA.

Contrast-enhanced magnetic resonance imaging (MRI) allows rapid non-invasive diagnosis of central nervous system (CNS) pathologies such as multiple sclerosis (MS). Current gadolinium-based contrast agents must be administered at high doses, are excreted by the kidney, and some formulations are associated with toxicity in patients with renal insufficiency. The development of nanoparticle carriers for targeted delivery of gadolinium to sites of disease would increase specificity, as well as decrease the dose of gadolinium required to obtain sufficient contrast for disease diagnosis. The plant virus, cowpea mosaic virus (CPMV), is a biocompatible nanoparticle platform for imaging applications. Gadolinium is rapidly incorporated into the interior of the CPMV capsid without disrupting particle integrity, and CPMV-Gd particles have relaxivity comparable to gadolinium chelates used clinically. Here we examine the ability of gadolinium-loaded CPMV particles (CPMV-Gd) to localize to lesions in the CNS in an animal model of MS, experimental autoimmune encephalomyelitis (EAE). The in vivo distribution of gadolinium-loaded CPMV (CPMV-Gd) was examined within the periphery and central nervous system (CNS). CPMV accumulated in inflammatory lesions within the brain and spinal cord, and specifically associated with CD11b and CD11c cells. These results demonstrate that CPMV is an attractive nanoparticle chelate for gadolinium for in vivo applications and may have clinical utility as a contrast agent for the detection of autoimmune demyelinating diseases of the CNS.
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http://dx.doi.org/10.1039/c3tb20521eDOI Listing
October 2013

Lymphocytes with cytotoxic activity induce rapid microtubule axonal destabilization independently and before signs of neuronal death.

ASN Neuro 2013 Feb 6;5(1):e00105. Epub 2013 Feb 6.

BloodCenter of Wisconsin, Blood Research Institute, Milwaukee, WI 53226, USA.

MS (multiple sclerosis) is the most prevalent autoimmune disease of the CNS (central nervous system) historically characterized as an inflammatory and demyelinating disease. More recently, extensive neuronal pathology has lead to its classification as a neurodegenerative disease as well. While the immune system initiates the autoimmune response it remains unclear how it orchestrates neuronal damage. In our previous studies, using in vitro cultured embryonic neurons, we demonstrated that MBP (myelin basic protein)-specific encephalitogenic CD4 T-cells induce early neuronal damage. In an extension of those studies, here we show that polarized CD4 Th1 and Th17 cells as wells as CD8 T-cells and NK (natural killer) cells induce microtubule destabilization within neurites in a contact-independent manner. Owing to the cytotoxic potential of these immune cells, we isolated the luminal components of lytic granules and determined that they were sufficient to drive microtubule destabilization. Since lytic granules contain cytolytic proteins, we determined that the induction of microtubule destabilization occurred prior to signs of apoptosis. Furthermore, we determined that microtubule destabilization was largely restricted to axons, sparing dendrites. This study demonstrated that lymphocytes with cytolytic activity have the capacity to directly drive MAD (microtubule axonal destabilization) in a bystander manner that is independent of neuronal death.
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http://dx.doi.org/10.1042/AN20120087DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3565378PMC
February 2013

A view from above: cloud plots to visualize global metabolomic data.

Anal Chem 2013 Jan 26;85(2):798-804. Epub 2012 Dec 26.

Washington University, Department of Chemistry, Saint Louis, Missouri 63110, USA.

Global metabolomics describes the comprehensive analysis of small molecules in a biological system without bias. With mass spectrometry-based methods, global metabolomic data sets typically comprise thousands of peaks, each of which is associated with a mass-to-charge ratio, retention time, fold change, p-value, and relative intensity. Although several visualization schemes have been used for metabolomic data, most commonly used representations exclude important data dimensions and therefore limit interpretation of global data sets. Given that metabolite identification through tandem mass spectrometry data acquisition is a time-limiting step of the untargeted metabolomic workflow, simultaneous visualization of these parameters from large sets of data could facilitate compound identification and data interpretation. Here, we present such a visualization scheme of global metabolomic data using a so-called "cloud plot" to represent multidimensional data from septic mice. While much attention has been dedicated to lipid compounds as potential biomarkers for sepsis, the cloud plot shows that alterations in hydrophilic metabolites may provide an early signature of the disease prior to the onset of clinical symptoms. The cloud plot is an effective representation of global mass spectrometry-based metabolomic data, and we describe how to extract it as standard output from our XCMS metabolomic software.
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http://dx.doi.org/10.1021/ac3029745DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3716252PMC
January 2013

Interaction of cowpea mosaic virus nanoparticles with surface vimentin and inflammatory cells in atherosclerotic lesions.

Nanomedicine (Lond) 2012 Jun 6;7(6):877-88. Epub 2012 Mar 6.

University of California, San Diego, Skaggs School of Pharmacy, La Jolla, CA 92093-0749, USA.

Aims: Detection of atherosclerosis has generally been limited to the late stages of development, after cardiovascular symptoms present or a clinical event occurs. One possibility for early detection is the use of functionalized nanoparticles. The aim of this study was the early imaging of atherosclerosis using nanoparticles with a natural affinity for inflammatory cells in the lesion.

Materials & Methods: We investigated uptake of cowpea mosaic virus by macrophages and foam cells in vitro and correlated this with vimentin expression. We also examined the ability of cowpea mosaic virus to interact with atherosclerotic lesions in a murine model of atherosclerosis.

Results & Conclusion: We found that uptake of cowpea mosaic virus is increased in areas of atherosclerotic lesion. This correlated with increased surface vimentin in the lesion compared with nonlesion vasculature. In conclusion, cowpea mosaic virus and its vimentin-binding region holds potential for use as a targeting ligand for early atherosclerotic lesions, and as a probe for detecting upregulation of surface vimentin during inflammation.
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http://dx.doi.org/10.2217/nnm.11.185DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3567616PMC
June 2012

Inhibition of fatty acid metabolism ameliorates disease activity in an animal model of multiple sclerosis.

Sci Rep 2011 1;1:79. Epub 2011 Sep 1.

Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California , San Diego, 9500 Gilman Drive, La Jolla, California. 92093. USA.

Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system and a leading cause of neurological disability. The complex immunopathology and variable disease course of multiple sclerosis have limited effective treatment of all patients. Altering the metabolism of immune cells may be an attractive strategy to modify their function during autoimmunity. We examined the effect of inhibiting fatty acid metabolism in experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Mice treated with an inhibitor of carnitine palmitoyltransferase 1 (CPT-1), the rate-limiting enzyme in the beta-oxidation of fatty acids, showed a reduction in disease severity as well as less inflammation and demyelination. Inhibition of CPT-1 in encephalitogenic T-cells resulted in increased apoptosis and reduced inflammatory cytokine production. These results suggest that disruption of fatty acid metabolism promotes downregulation of inflammation in the CNS and that this metabolic pathway is a potential therapeutic target for multiple sclerosis.
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http://dx.doi.org/10.1038/srep00079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3216566PMC
August 2013

Metabolomics implicates altered sphingolipids in chronic pain of neuropathic origin.

Nat Chem Biol 2012 Jan 22;8(3):232-4. Epub 2012 Jan 22.

Department of Chemistry, Washington University School of Medicine, St. Louis, Missouri, USA.

Neuropathic pain is a debilitating condition for which the development of effective treatments has been limited by an incomplete understanding of its chemical basis. We show by using untargeted metabolomics that sphingomyelin-ceramide metabolism is altered in the dorsal horn of rats with neuropathic pain and that the upregulated, endogenous metabolite N,N-dimethylsphingosine induces mechanical hypersensitivity in vivo. These results demonstrate the utility of metabolomics to implicate unexplored biochemical pathways in disease.
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http://dx.doi.org/10.1038/nchembio.767DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3567618PMC
January 2012

Viral nanoparticles associate with regions of inflammation and blood brain barrier disruption during CNS infection.

J Neuroimmunol 2009 Jun 25;211(1-2):66-72. Epub 2009 Apr 25.

Department of Cell Biology and Center for Integrative Molecular Biosciences, The Scripps Research Institute, La Jolla, CA 92037, United States.

Targeted treatment of inflammatory diseases of the central nervous system (CNS) remains problematic due to the complex pathogenesis of these disorders and difficulty in drug delivery. The plant virus, cowpea mosaic virus (CPMV), has recently been explored as a nanoparticle delivery system for therapeutics targeting a number of diseases including cancer and neurodegeneration. To understand the biodistribution of CPMV in the CNS, we examined CPMV uptake during infection of mice with neurotropic mouse hepatitis virus (MHV). CPMV localized mainly to the CNS endothelium in areas that contained an intact blood brain barrier. However, in inflammatory lesions containing macrophage/microglial cell infiltration and IgG, CPMV could be detected in the brain parenchyma. Furthermore, CPMV showed rapid internalization in an in vitro model of the BBB. These results suggest that CPMV particles could be used as a vehicle to deliver therapeutics to the damaged CNS during neurodegenerative and infectious diseases of the CNS.
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http://dx.doi.org/10.1016/j.jneuroim.2009.03.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2858070PMC
June 2009

Direct suppression of CNS autoimmune inflammation via the cannabinoid receptor CB1 on neurons and CB2 on autoreactive T cells.

Nat Med 2007 Apr 1;13(4):492-7. Epub 2007 Apr 1.

BloodCenter of Wisconsin, Blood Research Institute, Milwaukee, Wisconsin 53226, USA.

The cannabinoid system is immunomodulatory and has been targeted as a treatment for the central nervous system (CNS) autoimmune disease multiple sclerosis. Using an animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), we investigated the role of the CB(1) and CB(2) cannabinoid receptors in regulating CNS autoimmunity. We found that CB(1) receptor expression by neurons, but not T cells, was required for cannabinoid-mediated EAE suppression. In contrast, CB(2) receptor expression by encephalitogenic T cells was critical for controlling inflammation associated with EAE. CB(2)-deficient T cells in the CNS during EAE exhibited reduced levels of apoptosis, a higher rate of proliferation and increased production of inflammatory cytokines, resulting in severe clinical disease. Together, our results demonstrate that the cannabinoid system within the CNS plays a critical role in regulating autoimmune inflammation, with the CNS directly suppressing T-cell effector function via the CB(2) receptor.
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http://dx.doi.org/10.1038/nm1561DOI Listing
April 2007