Publications by authors named "Jonathan Jantsch"

91 Publications

Salt Transiently Inhibits Mitochondrial Energetics in Mononuclear Phagocytes.

Circulation 2021 Apr 28. Epub 2021 Apr 28.

Experimental and Clinical Research Center, a joint cooperation of Max Delbrück Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, Berlin, Germany; DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and HumboldtUniversität zu Berlin, Berlin, Germany; Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.

Dietary high salt (HS) is a leading risk factor for mortality and morbidity. Serum sodium transiently increases postprandially, but can also accumulate at sites of inflammation affecting differentiation and function of innate and adaptive immune cells. Here, we focus on how changes in extracellular sodium, mimicking alterations in the circulation and tissues, affect the early metabolic, transcriptional and functional adaption of human and murine mononuclear phagocytes (MNP). Using Seahorse technology, pulsed stable isotope-resolved metabolomics and enzyme activity assays we characterize the central carbon metabolism and mitochondrial function of human and murine MNP under HS . HS as well as pharmacologic uncoupling of the electron transport chain (ETC) under normal salt (NS) is used to analyze mitochondrial function on immune cell activation and function (as determined by killing and CD4 T cell migration capacity). In two independent clinical studies we analyze the impact of a HS diet over two weeks (NCT02509962) and short-term salt challenge by a single meal (NCT04175249) on mitochondrial function of human monocytes . Extracellular sodium was taken up into the intracellular compartment followed by the inhibition of mitochondrial respiration in murine and human macrophages (MΦ). Mechanistically, HS reduces mitochondrial membrane potential, ETC complex II activity, oxygen consumption, and ATP production independently of the polarization status of MΦ. Subsequently, cell activation is altered with improved bactericidal function in HS-treated M1-like MΦ and diminished CD4+ T cell migration in HS-treated M2-like MΦ. Pharmacologic uncoupling of the ETC under NS phenocopies HS-induced transcriptional changes and bactericidal function of human and murine MNP. Clinically, also rise in plasma sodium concentration within the physiological range reversibly reduces mitochondrial function in human monocytes. In both, a 14-day and single meal HS challenge, healthy volunteers displayed a plasma sodium increase of ̃x = 2 and ̃x = 2.3, respectively, that correlated with decreased monocytic mitochondrial oxygen consumption. Our data identify the disturbance of mitochondrial respiration as the initial step by which HS mechanistically influences immune cell function. While these functional changes might help to resolve bacterial infections, a shift towards pro-inflammation could accelerate inflammatory CVD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/CIRCULATIONAHA.120.052788DOI Listing
April 2021

Importance of the PD-1/PD-L1 Axis for Malignant Transformation and Risk Assessment of Oral Leukoplakia.

Biomedicines 2021 Feb 16;9(2). Epub 2021 Feb 16.

Department of Oral and Maxillofacial Surgery, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany.

Background: The programmed cell death ligand 1/programmed cell death receptor 1 (PD-L1/PD-1) Immune Checkpoint is an important modulator of the immune response. Overexpression of the receptor and its ligands is involved in immunosuppression and the failure of an immune response against tumor cells. PD-1/PD-L1 overexpression in oral squamous cell carcinoma (OSCC) compared to healthy oral mucosa (NOM) has already been demonstrated. However, little is known about its expression in oral precancerous lesions like oral leukoplakia (OLP). The aim of the study was to investigate whether an increased expression of PD-1/PD-L1 already exists in OLP and whether it is associated with malignant transformation.

Material And Methods: PD-1 and PD-L1 expression was immunohistologically analyzed separately in the epithelium (E) and the subepithelium (S) of OLP that had undergone malignant transformation within 5 years (T-OLP), in OLP without malignant transformation (N-OLP), in corresponding OSCC and in NOM. Additionally, RT-qPCR analysis for PD-L1 expression was done in the entire tissues. Additionally, the association between overexpression and malignant transformation, dysplasia and inflammation were examined.

Results: Compared to N-OLP, there were increased levels of PD-1 protein in the epithelial and subepithelial layers of T-OLP (p = 0.001; p = 0.005). There was no significant difference in PD-L1 mRNA expression between T-OLP and N-OLP ( = 0.128), but the fold-change increase between these groups was significant (Relative Quantification (RQ) = 3.1). In contrast to N-OLP, the PD-L1 protein levels were significantly increased in the epithelial layers of T-OLP ( = 0.007), but not in its subepithelial layers ( = 0.25). Importantly, increased PD-L1 levels were significantly associated to malignant transformation within 5 years.

Conclusion: Increased levels of PD-1 and PD-L1 are related to malignant transformation in OLP and may represent a promising prognostic indicator to determine the risk of malignant progression of OLP. Increased PD-L1 levels might establish an immunosuppressive microenvironment, which could favor immune escape and thereby contribute to malignant transformation. Hence, checkpoint inhibitors could counteract tumor development in OLP and may serve as efficient therapeutic strategy in patients with high-risk precancerous lesions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/biomedicines9020194DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7920045PMC
February 2021

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition).

Autophagy 2021 Jan 8;17(1):1-382. Epub 2021 Feb 8.

University of Crete, School of Medicine, Laboratory of Clinical Microbiology and Microbial Pathogenesis, Voutes, Heraklion, Crete, Greece; Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology (IMBB), Heraklion, Crete, Greece.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/15548627.2020.1797280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996087PMC
January 2021

Mechanical Stress Induce PG-E2 in Murine Synovial Fibroblasts Originating from the Temporomandibular Joint.

Cells 2021 Feb 1;10(2). Epub 2021 Feb 1.

Department of Orthodontics, University Medical Centre of Regensburg, D-93053 Regensburg, Germany.

Genetic predisposition, traumatic events, or excessive mechanical exposure provoke arthritic changes in the temporomandibular joint (TMJ). We analysed the impact of mechanical stress that might be involved in the development and progression of TMJ osteoarthritis (OA) on murine synovial fibroblasts (SFs) of temporomandibular origin. SFs were subjected to different protocols of mechanical stress, either to a high-frequency tensile strain for 4 h or to a tensile strain of varying magnitude for 48 h. The TMJ OA induction was evaluated based on the gene and protein secretion of inflammatory factors (, , , , , , , PG-E2), subchondral bone remodelling (, ), and extracellular matrix components (, , collagen and hyaluronic acid deposition) using RT-qPCR, ELISA, and HPLC. A short high-frequency tensile strain had only minor effects on inflammatory factors and no effects on the subchondral bone remodelling induction or matrix constituent production. A prolonged tensile strain of moderate and advanced magnitude increased the expression of inflammatory factors. An advanced tensile strain enhanced the and PG-E2 expression, while the expression of further inflammatory factors were decreased. The tensile strain protocols had no effects on the expression, while the advanced tensile strain significantly reduced the deposition of matrix constituent contents of collagen and hyaluronic acid. The data indicates that the application of prolonged advanced mechanical stress on SFs promote PG-E2 protein secretion, while the deposition of extracellular matrix components is decreased.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells10020298DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7912861PMC
February 2021

and Tumor Necrosis Factor-Alpha Stimulate Synthesis of Visfatin by Human Macrophages.

Int J Mol Sci 2021 Jan 27;22(3). Epub 2021 Jan 27.

Department of Periodontology and Operative Dentistry, University Medical Center, University of Mainz, 55131 Mainz, Germany.

There is little known about the effect of the periodontopathogen on macrophages as key cells of the innate immune defense in the periodontium. Therefore, the aim of the present study was to investigate the effect of and additionally of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) on visfatin and other pro-inflammatory and proteolytic molecules associated with periodontitis in human macrophages. The presence of macrophage markers CD14, CD86, CD68, and CD163 was examined in gingival biopsies from healthy individuals and periodontitis patients. Human macrophages were incubated with and TNFα for up to 2 d. The effects of both stimulants on macrophages were determined by real-time PCR, ELISA, immunocytochemistry, and immunofluorescence. was able to significantly stimulate the synthesis of visfatin by human macrophages using TLR2 and MAPK pathways. In addition to visfatin, was also able to increase the synthesis of cyclooxygenase 2, TNFα, and matrix metalloproteinase 1. Like , TNFα was also able to stimulate the production of these proinflammatory and proteolytic molecules. Our results highlight the pathogenetic role of in periodontal diseases and also underline the involvement of visfatin in the aetiopathogenesis of periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms22031235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7865436PMC
January 2021

Autopsy findings after long-term treatment of COVID-19 patients with microbiological correlation.

Virchows Arch 2021 Jan 20. Epub 2021 Jan 20.

Institute of Clinical Microbiology and Hygiene, Regensburg University Hospital, Regensburg, Germany.

Between April and June 2020, i.e., during the first wave of pandemic coronavirus disease 2019 (COVID-19), 55 patients underwent long-term treatment in the intensive care unit at the University Hospital of Regensburg. Most of them were transferred from smaller hospitals, often due to the need for an extracorporeal membrane oxygenation system. Autopsy was performed in 8/17 COVID-19-proven patients after long-term treatment (mean: 33.6 days). Autopsy revealed that the typical pathological changes occurring during the early stages of the disease (e.g., thrombosis, endothelitis, capillaritis) are less prevalent at this stage, while severe diffuse alveolar damage and especially coinfection with different fungal species were the most conspicuous finding. In addition, signs of macrophage activation syndrome was detected in 7 of 8 patients. Thus, fungal infections were a leading cause of death in our cohort of severely ill patients and may alter clinical management of patients, particularly in long-term periods of treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00428-020-03014-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7816067PMC
January 2021

Dietary Salt Accelerates Orthodontic Tooth Movement by Increased Osteoclast Activity.

Int J Mol Sci 2021 Jan 9;22(2). Epub 2021 Jan 9.

Department of Orthodontics, University Hospital Regensburg, 93053 Regensburg, Germany.

Dietary salt uptake and inflammation promote sodium accumulation in tissues, thereby modulating cells like macrophages and fibroblasts. Previous studies showed salt effects on periodontal ligament fibroblasts and on bone metabolism by expression of nuclear factor of activated T-cells-5 (NFAT-5). Here, we investigated the impact of salt and NFAT-5 on osteoclast activity and orthodontic tooth movement (OTM). After treatment of osteoclasts without (NS) or with additional salt (HS), we analyzed gene expression and the release of tartrate-resistant acid phosphatase and calcium phosphate resorption. We kept wild-type mice and mice lacking NFAT-5 in myeloid cells either on a low, normal or high salt diet and inserted an elastic band between the first and second molar to induce OTM. We analyzed the expression of genes involved in bone metabolism, periodontal bone loss, OTM and bone density. Osteoclast activity was increased upon HS treatment. HS promoted periodontal bone loss and OTM and was associated with reduced bone density. Deletion of NFAT-5 led to increased osteoclast activity with NS, whereas we detected impaired OTM in mice. Dietary salt uptake seems to accelerate OTM and induce periodontal bone loss due to reduced bone density, which may be attributed to enhanced osteoclast activity. NFAT-5 influences this reaction to HS, as we detected impaired OTM and osteoclast activity upon deletion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms22020596DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7827744PMC
January 2021

Role and Regulation of Mechanotransductive HIF-1α Stabilisation in Periodontal Ligament Fibroblasts.

Int J Mol Sci 2020 Dec 15;21(24). Epub 2020 Dec 15.

Department of Orthodontics, University Hospital Regensburg, 93053 Regensburg, Germany.

Orthodontic tooth movement (OTM) creates compressive and tensile strain in the periodontal ligament, causing circulation disorders. Hypoxia-inducible factor 1α (HIF-1α) has been shown to be primarily stabilised by compression, but not hypoxia in periodontal ligament fibroblasts (PDLF) during mechanical strain, which are key regulators of OTM. This study aimed to elucidate the role of heparan sulfate integrin interaction and downstream kinase phosphorylation for HIF-1α stabilisation under compressive and tensile strain and to which extent downstream synthesis of VEGF and prostaglandins is HIF-1α-dependent in a model of simulated OTM in PDLF. PDLF were subjected to compressive or tensile strain for 48 h. In various setups HIF-1α was experimentally stabilised (DMOG) or destabilised (YC-1) and mechanotransduction was inhibited by surfen and genistein. We found that HIF-1α was not stabilised by tensile, but rather by compressive strain. HIF-1α stabilisation had an inductive effect on prostaglandin and VEGF synthesis. As expected, HIF-1α destabilisation reduced VEGF expression, whereas prostaglandin synthesis was increased. Inhibition of integrin mechanotransduction via surfen or genistein prevented stabilisation of HIF-1α. A decrease in VEGF expression was observed, but not in prostaglandin synthesis. Stabilisation of HIF-1α via integrin mechanotransduction and downstream phosphorylation of kinases seems to be essential for the induction of VEGF, but not prostaglandin synthesis by PDLF during compressive (but not tensile) orthodontic strain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21249530DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7765204PMC
December 2020

Oral Health, Oral Microbiota, and Incidence of Stroke-Associated Pneumonia-A Prospective Observational Study.

Front Neurol 2020 6;11:528056. Epub 2020 Nov 6.

Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany.

Stroke-associated pneumonia is a major cause for poor outcomes in the post-acute phase after stroke. Several studies have suggested potential links between neglected oral health and pneumonia. Therefore, the aim of this prospective observational study was to investigate oral health and microbiota and incidence of pneumonia in patients consecutively admitted to a stroke unit with stroke-like symptoms. This study involved three investigation timepoints. The baseline investigation (within 24 h of admission) involved collection of demographic, neurological, and immunological data; dental examinations; and microbiological sampling (saliva and subgingival plaque). Further investigation timepoints at 48 or 120 h after baseline included collection of immunological data and microbiological sampling. Microbiological samples were analyzed by culture technique and by 16S rRNA amplicon sequencing. From the 99 patients included in this study, 57 were diagnosed with stroke and 42 were so-called stroke mimics. From 57 stroke patients, 8 (14%) developed pneumonia. Stroke-associated pneumonia was significantly associated with higher age, dysphagia, greater stroke severity, embolectomy, nasogastric tubes, and higher baseline C-reactive protein (CRP). There were trends toward higher incidence of pneumonia in patients with more missing teeth and worse oral hygiene. Microbiological analyses showed no relevant differences regarding microbial composition between the groups. However, there was a significant ecological shift over time in the pneumonia patients, probably due to antibiotic treatment. This prospective observational study investigating associations between neglected oral health and incidence of SAP encourages investigations in larger patient cohorts and implementation of oral hygiene programs in stroke units that may help reducing the incidence of stroke-associated pneumonia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fneur.2020.528056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677513PMC
November 2020

Mechanisms controlling bacterial infection in myeloid cells under hypoxic conditions.

Cell Mol Life Sci 2021 Mar 30;78(5):1887-1907. Epub 2020 Oct 30.

Mikrobiologisches Institut, Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, 91054, Erlangen, Germany.

Various factors of the tissue microenvironment such as the oxygen concentration influence the host-pathogen interaction. During the past decade, hypoxia-driven signaling via hypoxia-inducible factors (HIF) has emerged as an important factor that affects both the pathogen and the host. In this chapter, we will review the current knowledge of this complex interplay, with a particular emphasis given to the impact of hypoxia and HIF on the inflammatory and antimicrobial activity of myeloid cells, the bacterial responses to hypoxia and the containment of bacterial infections under oxygen-limited conditions. We will also summarize how low oxygen concentrations influence the metabolism of neutrophils, macrophages and dendritic cells. Finally, we will discuss the consequences of hypoxia and HIFα activation for the invading pathogen, with a focus on Pseudomonas aeruginosa, Mycobacterium tuberculosis, Coxiella burnetii, Salmonella enterica and Staphylococcus aureus. This includes a description of the mechanisms and microbial factors, which the pathogens use to sense and react to hypoxic conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00018-020-03684-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7966188PMC
March 2021

The role of HIF-1α in nicotine-induced root and bone resorption during orthodontic tooth movement.

Eur J Orthod 2020 Oct 12. Epub 2020 Oct 12.

Department of Orthodontics, University Medical Centre of Regensburg, Germany.

Background: In orthodontic tooth movement (OTM), pseudo-inflammatory processes occur that are similar to those of nicotine-induced periodontitis. Previous studies have shown that nicotine accelerates OTM, but induces periodontal bone loss and dental root resorption via synergistically increased osteoclastogenesis. This study aimed to investigate the role of hypoxia-inducible factor 1 alpha (HIF-1α) in nicotine-induced osteoclastogenesis during OTM.

Materials/methods: Male Fischer-344 rats were treated with l-Nicotine (1.89 mg/kg/day s.c., N = 10) or NaCl solution (N = 10). After a week of premedication, a NiTi spring was inserted to mesialize the first upper left molar. The extent of dental root resorption, osteoclastogenesis, and HIF-1α protein expression was determined by (immuno)histology, as well as bone volume (BV/TV) and trabecular thickness (TbTh) using µCT. Receptor activator of nuclear factor of activated B-cells ligand (RANK-L), osteoprotegerin (OPG), and HIF-1α expression were examined at the protein level in periodontal ligament fibroblasts (PDLF) exposed to pressure, nicotine and/or hypoxia, as well as PDLF-induced osteoclastogenesis in co-culture experiments with osteoclast progenitor cells.

Results: Nicotine favoured dental root resorptions and osteoclastogenesis during OTM, while BV/TV and TbTh were only influenced by force. This nicotine-induced increase does not appear to be mediated by HIF-1α, since HIF-1α was stabilized by force application and hypoxia, but not by nicotine. The in vitro data showed that the hypoxia-induced increase in RANK-L/OPG expression ratio and PDLF-mediated osteoclastogenesis was less pronounced than the nicotine-induced increase.

Conclusions: Study results indicate that the nicotine-induced increase in osteoclastogenesis and periodontal bone resorption during OTM may not be mediated by hypoxic effects or HIF-1α stabilization in the context of nicotine-induced vasoconstriction, but rather by an alternative mechanism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ejo/cjaa057DOI Listing
October 2020

Impact of salt and the osmoprotective transcription factor NFAT-5 on macrophages during mechanical strain.

Immunol Cell Biol 2021 Jan 11;99(1):84-96. Epub 2020 Oct 11.

Department of Orthodontics, University Hospital Regensburg, Regensburg, 93053, Germany.

Myeloid cells regulate bone density in response to increased salt (NaCl) intake via the osmoprotective transcription factor, nuclear factor of activated T cells-5 (NFAT-5). Because orthodontic tooth movement (OTM) is a pseudoinflammatory immunological process, we investigated the influence of NaCl and NFAT-5 on the expression pattern of macrophages in a model of simulated OTM. RAW264.7 macrophages were exposed for 4 h to 2 g cm compressive or 16% tensile or no mechanical strain (control), with or without the addition of 40 mm NaCl. We analyzed the expression of inflammatory genes and proteins [tumor necrosis factor (TNF), interleukin (IL)-6 and prostaglandin endoperoxide synthase-2 (Ptgs-2)/prostaglandin E2 (PG-E2)] by real-time-quantitative PCR and ELISA. To investigate the role of NFAT-5 in these responses, NFAT-5 was both constitutively expressed and silenced. Salt and compressive strain, but not tensile strain increased the expression of NFAT-5 and most tested inflammatory factors in macrophages. NaCl induced the expression of Ptgs-2/PG-E2 and TNF, whereas secretion of IL-6 was inhibited. Similarly, a constitutive expression of NFAT-5 reduced IL-6 expression, while increasing Ptgs-2/PG-E2 and TNF expression. Silencing of NFAT-5 upregulated IL-6 and reduced Ptgs-2/PG-E2 and TNF expression. Salt had an impact on the expression profile of macrophages as a reaction to compressive and tensile strain that occur during OTM. This was mediated via NFAT-5, which surprisingly also seems to play a regulatory role in mechanotransduction of compressive strain. Sodium accumulation in the periodontal ligament caused by dietary salt consumption might propagate local osteoclastogenesis via increased local inflammation and thus OTM velocity, but possibly also entail side effects such as dental root resorptions or periodontal bone loss.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/imcb.12398DOI Listing
January 2021

Role of Oxygen Supply in Macrophages in a Model of Simulated Orthodontic Tooth Movement.

Mediators Inflamm 2020 29;2020:5802435. Epub 2020 Jul 29.

Department of Orthodontics, University Hospital Regensburg, 93053 Regensburg, Germany.

Apart from periodontal ligament fibroblasts, immune cells like macrophages also play an important mediating role in orthodontic tooth movement (OTM). Upon orthodontic force application to malpositioned teeth, macrophages in the periodontal ligament get exposed to both mechanical strain and hypoxic conditions (via a compression of blood vessels). In this study, we assessed the relative impact of orthodontically induced mechanical strain and hypoxic conditions on macrophages for the mediation and regulation of OTM. Macrophages were stimulated with physiological orthodontic compressive forces of 2 g/cm for 4 h and 24 h on gas-impermeable or gas-permeable cell culture plates under normoxic or hypoxic cell culture conditions. We quantified expression of genes involved in inflammation (, , and ), extracellular remodelling (), and angiogenesis () by RT-qPCR. Furthermore, we analysed HIF-1, prostaglandin-E2, and VEGF protein expression via immunoblotting or ELISA. Mechanical strain and oxygen supply both differentially affected expression of genes and proteins involved in inflammation and angiogenesis. In this context, we found that HIF-1 protein levels were elevated by combined mechanical strain and hypoxic conditions, whereas gas-permeable plates providing sufficient oxygen supply prevented HIF-1 stabilization at the protein level after pressure application on macrophages. Our results thus indicate that macrophages involved in the mediation of OTM are affected by and respond differently to hypoxic conditions and mechanical compressive strain, which occur concomitantly during OTM, than periodontal ligament fibroblasts (PDLF), thus indicating different roles of these cells in the regulation of OTM at the cellular-molecular level. We further observed that contrary to PDLF HIF-1 stabilization in macrophages is rather induced via the decreased oxygen supply associated with OTM than via mechanotransduction by mechanical strain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/5802435DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7424081PMC
July 2020

A highly specific and sensitive serological assay detects SARS-CoV-2 antibody levels in COVID-19 patients that correlate with neutralization.

Infection 2021 Feb 21;49(1):75-82. Epub 2020 Aug 21.

Department for Infection Control and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany.

Objective: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic challenges national health systems and the global economy. Monitoring of infection rates and seroprevalence can guide public health measures to combat the pandemic. This depends on reliable tests on active and former infections. Here, we set out to develop and validate a specific and sensitive enzyme linked immunosorbent assay (ELISA) for detection of anti-SARS-CoV-2 antibody levels.

Methods: In our ELISA, we used SARS-CoV-2 receptor-binding domain (RBD) and a stabilized version of the spike (S) ectodomain as antigens. We assessed sera from patients infected with seasonal coronaviruses, SARS-CoV-2 and controls. We determined and monitored IgM-, IgA- and IgG-antibody responses towards these antigens. In addition, for a panel of 22 sera, virus neutralization and ELISA parameters were measured and correlated.

Results: The RBD-based ELISA detected SARS-CoV-2-directed antibodies, did not cross-react with seasonal coronavirus antibodies and correlated with virus neutralization (R = 0.89). Seroconversion started at 5 days after symptom onset and led to robust antibody levels at 10 days after symptom onset. We demonstrate high specificity (99.3%; N = 1000) and sensitivity (92% for IgA, 96% for IgG and 98% for IgM; > 10 days after PCR-proven infection; N = 53) in serum.

Conclusions: With the described RBD-based ELISA protocol, we provide a reliable test for seroepidemiological surveys. Due to high specificity and strong correlation with virus neutralization, the RBD ELISA holds great potential to become a preferred tool to assess thresholds of protective immunity after infection and vaccination.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s15010-020-01503-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7441844PMC
February 2021

A highly specific and sensitive serological assay detects SARS-CoV-2 antibody levels in COVID-19 patients that correlate with neutralization.

Infection 2021 Feb 21;49(1):75-82. Epub 2020 Aug 21.

Department for Infection Control and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany.

Objective: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic challenges national health systems and the global economy. Monitoring of infection rates and seroprevalence can guide public health measures to combat the pandemic. This depends on reliable tests on active and former infections. Here, we set out to develop and validate a specific and sensitive enzyme linked immunosorbent assay (ELISA) for detection of anti-SARS-CoV-2 antibody levels.

Methods: In our ELISA, we used SARS-CoV-2 receptor-binding domain (RBD) and a stabilized version of the spike (S) ectodomain as antigens. We assessed sera from patients infected with seasonal coronaviruses, SARS-CoV-2 and controls. We determined and monitored IgM-, IgA- and IgG-antibody responses towards these antigens. In addition, for a panel of 22 sera, virus neutralization and ELISA parameters were measured and correlated.

Results: The RBD-based ELISA detected SARS-CoV-2-directed antibodies, did not cross-react with seasonal coronavirus antibodies and correlated with virus neutralization (R = 0.89). Seroconversion started at 5 days after symptom onset and led to robust antibody levels at 10 days after symptom onset. We demonstrate high specificity (99.3%; N = 1000) and sensitivity (92% for IgA, 96% for IgG and 98% for IgM; > 10 days after PCR-proven infection; N = 53) in serum.

Conclusions: With the described RBD-based ELISA protocol, we provide a reliable test for seroepidemiological surveys. Due to high specificity and strong correlation with virus neutralization, the RBD ELISA holds great potential to become a preferred tool to assess thresholds of protective immunity after infection and vaccination.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s15010-020-01503-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7441844PMC
February 2021

Effects of sodium chloride on the gene expression profile of periodontal ligament fibroblasts during tensile strain.

J Orofac Orthop 2020 Sep 6;81(5):360-370. Epub 2020 Jul 6.

Department of Orthodontics, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.

Purpose: During orthodontic tooth movement, pressure and tension zones develop in the periodontal ligament, and periodontal ligament fibroblasts (PDLF) become exposed to mechanical strain. Enhanced salt (NaCl) concentrations are known to modulate responses of PDLF and immune cells to different stimuli like mechanical strain. Here, we investigated the impact of tensile strain on the gene expression profile of PDLF under normal (NS) and high salt (HS) conditions.

Methods: After preincubation under NS or HS (+40 mM NaCl in medium) conditions for 24 h, PDLF were stretched 16% for 48 h using custom-made spherical cap silicone stamps using an established and published setup. After determination of cell number and cytotoxicity, we analyzed expression of genes involved in extracellular matrix reorganization, angiogenesis, bone remodeling, and inflammation by quantitative real-time polymerase chain reaction (RT-qPCR).

Results: Tensile strain did not affect the expression of genes involved in angiogenesis or extracellular matrix reorganization by PDLF, which however modulate inflammatory responses and bone remodeling in reaction to 16% static tensile strain. Salt (NaCl) treatment triggered enhanced extracellular matrix formation, expression of cyclooxygenase 2 and bone metabolism in PDLF during tensile strain.

Conclusions: Salt (NaCl) consumption may influence orthodontic tooth movement and periodontal bone loss via modulation of extracellular matrix and bone metabolism. Excessive salt intake during orthodontic therapy may cause adverse effects regarding periodontal inflammation and bone resorption.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00056-020-00232-8DOI Listing
September 2020

NCX1 represents an ionic Na+ sensing mechanism in macrophages.

PLoS Biol 2020 06 22;18(6):e3000722. Epub 2020 Jun 22.

Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, Regensburg, Germany.

Inflammation and infection can trigger local tissue Na+ accumulation. This Na+-rich environment boosts proinflammatory activation of monocyte/macrophage-like cells (MΦs) and their antimicrobial activity. Enhanced Na+-driven MΦ function requires the osmoprotective transcription factor nuclear factor of activated T cells 5 (NFAT5), which augments nitric oxide (NO) production and contributes to increased autophagy. However, the mechanism of Na+ sensing in MΦs remained unclear. High extracellular Na+ levels (high salt [HS]) trigger a substantial Na+ influx and Ca2+ loss. Here, we show that the Na+/Ca2+ exchanger 1 (NCX1, also known as solute carrier family 8 member A1 [SLC8A1]) plays a critical role in HS-triggered Na+ influx, concomitant Ca2+ efflux, and subsequent augmented NFAT5 accumulation. Moreover, interfering with NCX1 activity impairs HS-boosted inflammatory signaling, infection-triggered autolysosome formation, and subsequent antibacterial activity. Taken together, this demonstrates that NCX1 is able to sense Na+ and is required for amplifying inflammatory and antimicrobial MΦ responses upon HS exposure. Manipulating NCX1 offers a new strategy to regulate MΦ function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pbio.3000722DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307728PMC
June 2020

Early OA Stage Like Response Occurs after Dynamic Stretching of Human Synovial Fibroblasts.

Int J Mol Sci 2020 May 29;21(11). Epub 2020 May 29.

Department of Orthodontics, University Medical Centre of Regensburg, D-93053 Regensburg, Germany.

As events triggering early osteoarthritis onset can be related to mechanical stress and proinflammatory signaling, we investigated the effect of different mechanical strain protocols on the expression of proinflammatory genes, as well as extracellular matrix remodelling in human synovial fibroblasts. Three distinct models of tensile stretching were applied: static isotropic tensile strain at 0 Hz, 16% tension for 48 h; short-term high-frequency cyclic tension at 1 Hz, 10% tension for 4 h; and dynamic tensile stretching for 48 h, consisting of two blocks of moderate stretching at 0.2 Hz, 2%, advanced stretching at 0.5 Hz, 15%, or a combination of both. General signs of inflammation were present after static isotropic tension, whereas short-term high-frequency cyclic tension showed increased levels of paired with diminished levels of . Reduced inflammatory effects of , , and were observed when exposed to advanced stretching. Long-term tensile strain induced extracellular matrix remodelling at the gene and protein levels. While hyaluronan acid synthesis was increased with static tensile strain, dynamic tensile stretching had a reducing effect. Our study revealed that proinflammatory markers were activated by mechanical strain as seen in static isotropic tension and short-term high-frequency tensile strain, whereas long-term exposure induced extracellular matrix remodelling processes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21113874DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7312748PMC
May 2020

Effects of Compressive and Tensile Strain on Macrophages during Simulated Orthodontic Tooth Movement.

Mediators Inflamm 2020 28;2020:2814015. Epub 2020 Apr 28.

Department of Orthodontics, University Hospital Regensburg, 93053 Regensburg, Germany.

During orthodontic tooth movement (OTM) to therapeutically correct the position of misaligned teeth, thus improving oral health and quality of life, fibroblasts, macrophages, and other immune cells within the periodontal ligament (PDL), which connects a tooth to its surrounding bone, are exposed to compressive and tensile strain. While it is known that PDL fibroblasts are critically involved in the biological regulation of OTM by a mechanotransductively triggered release of cytokines, it is unclear whether macrophages also react to pressure and tension in a similar manner thus impacting on or mediating OTM. RAW264.7 macrophages were seeded onto conventional 6-well cell culture plates for pressure or on Bioflex plates for tension assays and preincubated for 24 h. For simulation of physiological orthodontic compressive or tensile strain for 2 h, 4 h, 24 h, and 48 h, glass discs (2 g/cm) were placed or adherent macrophages isotropically stretched for 16%, respectively. We determined cell number, cytotoxicity, and gene/protein expression of /VEGF-A (macrophage-mediated angiogenesis), (extracellular matrix reorganization), and /PG-E2, /IL-6, and /TNF- (proinflammatory mediators) by RT-qPCR and ELISA. Compressive but not tensile strain resulted in a significant reduction in cell number after only 2 h. and expression was significantly enhanced within 24 h of compressive and in part tensile strain. Significantly increased /VEGF-A expression was detected within 4 h of pressure, but not during application of tensile strain. Expression of proinflammatory mediators /PG-E2, /IL-6, and /TNF- was significantly increased as early as 2-4 h after application of compressive or tensile strain. Our results indicate that macrophages respond early on to compressive and tensile strain occurring during OTM with an enhanced gene expression of proinflammatory cytokines, which could affect PDL fibroblasts, osteoblasts, and immune cells triggering or enhancing the biological mechanisms and osteoclastogenesis underlying OTM.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/2814015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204109PMC
April 2020

A high-salt diet compromises antibacterial neutrophil responses through hormonal perturbation.

Sci Transl Med 2020 03;12(536)

Institute of Experimental Immunology, University Hospital of Bonn, Rheinische Friedrich Wilhelm University, 53127 Bonn, Germany.

The Western diet is rich in salt, which poses various health risks. A high-salt diet (HSD) can stimulate immunity through the nuclear factor of activated T cells 5 (Nfat5)-signaling pathway, especially in the skin, where sodium is stored. The kidney medulla also accumulates sodium to build an osmotic gradient for water conservation. Here, we studied the effect of an HSD on the immune defense against uropathogenic -induced pyelonephritis, the most common kidney infection. Unexpectedly, pyelonephritis was aggravated in mice on an HSD by two mechanisms. First, on an HSD, sodium must be excreted; therefore, the kidney used urea instead to build the osmotic gradient. However, in contrast to sodium, urea suppressed the antibacterial functionality of neutrophils, the principal immune effectors against pyelonephritis. Second, the body excretes sodium by lowering mineralocorticoid production via suppressing aldosterone synthase. This caused an accumulation of aldosterone precursors with glucocorticoid functionality, which abolished the diurnal adrenocorticotropic hormone-driven glucocorticoid rhythm and compromised neutrophil development and antibacterial functionality systemically. Consistently, under an HSD, systemic infection was also aggravated in a glucocorticoid-dependent manner. Glucocorticoids directly induced Nfat5 expression, but pharmacological normalization of renal Nfat5 expression failed to restore the antibacterial defense. Last, healthy humans consuming an HSD for 1 week showed hyperglucocorticoidism and impaired antibacterial neutrophil function. In summary, an HSD suppresses intrarenal neutrophils Nfat5-independently by altering the local microenvironment and systemically by glucocorticoid-mediated immunosuppression. These findings argue against high-salt consumption during bacterial infections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/scitranslmed.aay3850DOI Listing
March 2020

Zoonotic spillover infections with Borna disease virus 1 leading to fatal human encephalitis, 1999-2019: an epidemiological investigation.

Lancet Infect Dis 2020 04 7;20(4):467-477. Epub 2020 Jan 7.

Department of Neuropathology, Technical University of Munich, Munich, Germany.

Background: In 2018-19, Borna disease virus 1 (BoDV-1), the causative agent of Borna disease in horses, sheep, and other domestic mammals, was reported in five human patients with severe to fatal encephalitis in Germany. However, information on case frequencies, clinical courses, and detailed epidemiological analyses are still lacking. We report the occurrence of BoDV-1-associated encephalitis in cases submitted to the Institute of Clinical Microbiology and Hygiene, Regensburg University Hospital, Regensburg, Germany, and provide a detailed description of newly identified cases of BoDV-1-induced encephalitis.

Methods: All brain tissues from 56 encephalitis cases from Bavaria, Germany, of putative viral origin (1999-2019), which had been submitted for virological testing upon request of the attending clinician and stored for stepwise diagnostic procedure, were systematically screened for BoDV-1 RNA. Two additional BoDV-1-positive cases were contributed by other diagnostic centres. Positive results were confirmed by deep sequencing, antigen detection, and determination of BoDV-1-reactive antibodies in serum and cerebrospinal fluid. Clinical and epidemiological data from infected patients were collected and analysed.

Findings: BoDV-1 RNA and bornavirus-reactive antibodies were detected in eight newly analysed encephalitis cases and the first human BoDV-1 isolate was obtained from an unequivocally confirmed human BoDV-1 infection from the endemic area. Six of the eight BoDV-1-positive patients had no record of immunosuppression before the onset of fatal disease, whereas two were immunocompromised after solid organ transplantation. Typical initial symptoms were headache, fever, and confusion, followed by various neurological signs, deep coma, and severe brainstem involvement. Seven of nine patients with fatal encephalitis of unclear cause were BoDV-1 positive within one diagnostic centre. BoDV-1 sequence information and epidemiological analyses indicated independent spillover transmissions most likely from the local wild animal reservoir.

Interpretation: BoDV-1 infection has to be considered as a potentially lethal zoonosis in endemic regions with reported spillover infections in horses and sheep. BoDV-1 infection can result in fatal encephalitis in immunocompromised and apparently healthy people. Consequently, all severe encephalitis cases of unclear cause should be tested for bornaviruses especially in endemic regions.

Funding: German Federal Ministry of Education and Research.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S1473-3099(19)30546-8DOI Listing
April 2020

Osteoprotective action of low-salt diet requires myeloid cell-derived NFAT5.

JCI Insight 2019 12 5;4(23). Epub 2019 Dec 5.

Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany.

Dietary salt consumption leads to cutaneous Na+ storage and is associated with various disorders, including osteopenia. Here, we explore the impact of Na+ and the osmoprotective transcription factor nuclear factor of activated T cell 5 (NFAT5) on bone density and osteoclastogenesis. Compared with treatment of mice with high-salt diet, low-salt diet (LSD) increased bone density, decreased osteoclast numbers, and elevated Na+ content and Nfat5 levels in the BM. This response to LSD was dependent on NFAT5 expressed in myeloid cells. Simulating in vivo findings, we exposed osteoclast precursors and osteoblasts to elevated Na+ content (high-salt conditions; HS¢), resulting in increased NFAT5 binding to the promotor region of RANKL decoy receptor osteoprotegerin (OPG). These data not only demonstrate that NFAT5 in myeloid cells determines the Na+ content in BM, but that NFAT5 is able to govern the expression of the osteoprotective gene OPG. This provides insights into mechanisms of Na+-induced cessation of osteoclastogenesis and offers potentially new targets for treating salt-induced osteopenia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/jci.insight.127868DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6962031PMC
December 2019

The role of mechanotransduction versus hypoxia during simulated orthodontic compressive strain-an in vitro study of human periodontal ligament fibroblasts.

Int J Oral Sci 2019 11 5;11(4):33. Epub 2019 Nov 5.

Department of Orthodontics, University Medical Centre of Regensburg, Franz-Josef-Strauß-Allee 11, D-93053, Regensburg, Germany.

During orthodontic tooth movement (OTM) mechanical forces trigger pseudo-inflammatory, osteoclastogenic and remodelling processes in the periodontal ligament (PDL) that are mediated by PDL fibroblasts via the expression of various signalling molecules. Thus far, it is unknown whether these processes are mainly induced by mechanical cellular deformation (mechanotransduction) or by concomitant hypoxic conditions via the compression of periodontal blood vessels. Human primary PDL fibroblasts were randomly seeded in conventional six-well cell culture plates with O-impermeable polystyrene membranes and in special plates with gas-permeable membranes (Lumox®, Sarstedt), enabling the experimental separation of mechanotransducive and hypoxic effects that occur concomitantly during OTM. To simulate physiological orthodontic compressive forces, PDL fibroblasts were stimulated mechanically at 2 g·cm for 48 h after 24 h of pre-incubation. We quantified the cell viability by MTT assay, gene expression by quantitative real-time polymerase chain reaction (RT-qPCR) and protein expression by western blot/enzyme-linked immunosorbent assays (ELISA). In addition, PDL-fibroblast-mediated osteoclastogenesis (TRAP cells) was measured in a 72-h coculture with RAW264.7 cells. The expression of HIF-1α, COX-2, PGE2, VEGF, COL1A2, collagen and ALPL, and the RANKL/OPG ratios at the mRNA/protein levels during PDL-fibroblast-mediated osteoclastogenesis were significantly elevated by mechanical loading irrespective of the oxygen supply, whereas hypoxic conditions had no significant additional effects. The cellular-molecular mediation of OTM by PDL fibroblasts via the expression of various signalling molecules is expected to be predominantly controlled by the application of force (mechanotransduction), whereas hypoxic effects seem to play only a minor role. In the context of OTM, the hypoxic marker HIF-1α does not appear to be primarily stabilized by a reduced O supply but is rather stabilised mechanically.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41368-019-0066-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6828658PMC
November 2019

The neuropathology of fatal encephalomyelitis in human Borna virus infection.

Acta Neuropathol 2019 10 26;138(4):653-665. Epub 2019 Jul 26.

Department of Neuropathology, School of Medicine, Institute of Pathology, Technical University Munich, Trogerstraße 18, 81675, Munich, Germany.

After many years of controversy, there is now recent and solid evidence that classical Borna disease virus 1 (BoDV-1) can infect humans. On the basis of six brain autopsies, we provide the first systematic overview on BoDV-1 tissue distribution and the lesion pattern in fatal BoDV-1-induced encephalitis. All brains revealed a non-purulent, lymphocytic sclerosing panencephalomyelitis with detection of BoDV-1-typical eosinophilic, spherical intranuclear Joest-Degen inclusion bodies. While the composition of histopathological changes was constant, the inflammatory distribution pattern varied interindividually, affecting predominantly the basal nuclei in two patients, hippocampus in one patient, whereas two patients showed a more diffuse distribution. By immunohistochemistry and RNA in situ hybridization, BoDV-1 was detected in all examined brain tissue samples. Furthermore, infection of the peripheral nervous system was observed. This study aims at raising awareness to human bornavirus encephalitis as differential diagnosis in lymphocytic sclerosing panencephalomyelitis. A higher attention to human BoDV-1 infection by health professionals may likely increase the detection of more cases and foster a clearer picture of the disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00401-019-02047-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6778062PMC
October 2019

Detection of carbapenemase-producing Enterobacterales and the BD Phoenix CPO Detect panel.

Expert Rev Mol Diagn 2019 08 1;19(8):659-665. Epub 2019 Aug 1.

Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg , Regensburg , Germany.

: Treatment options for infections with carbapenem-resistant Enterobacterales are strongly limited. New antimicrobials are not effective against all types of carbapenemases. Therefore, rapid and reliable antimicrobial susceptibility testing and identification of the resistance mechanism are important. : We assess several methods to determine carbapenemase production of Enterobacterales in culture and discuss the value of the novel automated BD Phoenix CPO Detect (BDPCPO) panel for the detection and classification of carbapenemases. : The meropenem minimum inhibitory concentration (MIC) range used in the BDPCPO panel includes the EUCAST screening breakpoint for the detection of carbapenemase producers. The phenotypic, inhibitor-based assay for detection of carbapenemase activity in the BDPCPO panel displays high sensitivity for carbapenemase detection while its specificity is modest. Therefore, confirmation testing of positive results is warranted. Nevertheless, implementing the BDPCPO panel has the potential to reduce time-to-result for detection and classification of carbapenemase producers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/14737159.2019.1645598DOI Listing
August 2019

Sodium-chloride-induced effects on the expression profile of human periodontal ligament fibroblasts with focus on simulated orthodontic tooth movement.

Eur J Oral Sci 2019 10 29;127(5):386-395. Epub 2019 Jun 29.

Department of Orthodontics, University Hospital Regensburg, Regensburg, Germany.

Increased salt (NaCl) consumption triggers chronic diseases such as hypertension or osteopenia. Its impact on orthodontic tooth movement and periodontitis, however, has not been investigated, although both processes are related to the immune system, with periodontal ligament fibroblasts (PDLFs) playing a key mediating role. Here, we investigated the impact of NaCl on the expression pattern of PDLFs in a model of simulated compressive orthodontic strain. Periodontal ligament fibroblasts were preincubated for 24 h with additional 0 or 40 mM NaCl and concurrently treated for another 48 h with or without compressive strain of 2 g cm . We analyzed the expression of genes and proteins involved in orthodontic tooth movement by reverse transcription quantitative polymerase chain reaction (RT-qPCR), ELISA, and immunoblot. Co-culture experiments were performed to observe PDLF-mediated osteoclastogenesis. A higher (40 mM) concentration of NaCl in the culture medium resulted in increased secretion of prostaglandin, expression of alkaline phosphatase, and expression of genes involved in extracellular matrix remodeling, but decreased compression-induced expression of the interleukin-6 (IL6) gene. The 40 mM concentration of NaCl also enhanced receptor activator of nuclear factor kappa-B ligand (RANKL) but reduced that of osteoprotegerin (OPG), resulting in upregulated PDLF-mediated osteoclastogenesis. A high NaCl concentration in the periodontal ligament, corresponding to a high-salt diet in vivo, may influence orthodontic tooth movement and periodontitis through increased secretion of prostaglandins by PDLFs and upregulated PDLF-mediated osteoclastogenesis, possibly accelerating orthodontic tooth movement and propagating periodontitis and periodontal bone loss.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/eos.12643DOI Listing
October 2019

Mononuclear phagocytes orchestrate prolyl hydroxylase inhibition-mediated renoprotection in chronic tubulointerstitial nephritis.

Kidney Int 2019 08 5;96(2):378-396. Epub 2019 Mar 5.

Department of Internal Medicine 4-Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and University Hospital Erlangen, Erlangen, Germany. Electronic address:

Prolyl hydroxylase domain enzyme inhibitors (PHDIs) stabilize hypoxia-inducible factors (HIFs), and are protective in models of acute ischemic and inflammatory kidney disease. Whether PHDIs also confer protection in chronic inflammatory kidney disease models remains unknown. Here we investigated long-term effects of PHDI treatment in adenine-induced nephropathy as a model for chronic tubulointerstitial nephritis. After three weeks, renal dysfunction and tubulointerstitial damage, including proximal and distal tubular injury, tubular dilation and renal crystal deposition were significantly attenuated in PHDI-treated (the isoquinoline derivative ICA and Roxadustat) compared to vehicle-treated mice with adenine-induced nephropathy. Crystal-induced renal fibrosis was only partially diminished by treatment with ICA. Renoprotective effects of ICA treatment could not be attributed to changes in adenine metabolism or urinary excretion of the metabolite 2,8-dihydroxyadenine. ICA treatment reduced inflammatory infiltrates of F4/80+ mononuclear phagocytes in the kidneys and supported a regulatory, anti-inflammatory immune response. Furthermore, interstitial deposition of complement C1q was decreased in ICA-treated mice fed an adenine-enriched diet. Tubular cell-specific HIF-1α and myeloid cell-specific HIF-1α and HIF-2α expression were not required for the renoprotective effects of ICA. In contrast, depletion of mononuclear phagocytes with clodronate largely abolished the nephroprotective effects of PHD inhibition. Thus, our findings indicate novel and potent systemic anti-inflammatory properties of PHDIs that confer preservation of kidney function and structure in chronic tubulointerstitial inflammation and might counteract kidney disease progression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.kint.2019.02.016DOI Listing
August 2019

Interplay of Na Balance and Immunobiology of Dendritic Cells.

Front Immunol 2019 29;10:599. Epub 2019 Mar 29.

Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, University of Regensburg, Regensburg, Germany.

Local Na balance emerges as an important factor of tissue microenvironment. On the one hand, immune cells impact on local Na levels. On the other hand, Na availability is able to influence immune responses. In contrast to macrophages, our knowledge of dendritic cells (DCs) in this state of affair is rather limited. Current evidence suggests that the impact of increased Na on DCs is context dependent. Moreover, it is conceivable that DC immunobiology might also be influenced by Na-rich-diet-induced changes of the gut microbiome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2019.00599DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6449459PMC
August 2020

HIF1A and NFAT5 coordinate Na-boosted antibacterial defense via enhanced autophagy and autolysosomal targeting.

Autophagy 2019 11 14;15(11):1899-1916. Epub 2019 Apr 14.

Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg , Regensburg , Germany.

Infection and inflammation are able to induce diet-independent Na-accumulation without commensurate water retention in afflicted tissues, which favors the pro-inflammatory activation of mouse macrophages and augments their antibacterial and antiparasitic activity. While Na-boosted host defense against the protozoan parasite is mediated by increased expression of the leishmanicidal NOS2 (nitric oxide synthase 2, inducible), the molecular mechanisms underpinning this enhanced antibacterial defense of mouse macrophages with high Na (HS) exposure are unknown. Here, we provide evidence that HS-increased antibacterial activity against was neither dependent on NOS2 nor on the phagocyte oxidase. In contrast, HS-augmented antibacterial defense hinged on HIF1A (hypoxia inducible factor 1, alpha subunit)-dependent increased autophagy, and NFAT5 (nuclear factor of activated T cells 5)-dependent targeting of intracellular to acidic autolysosomal compartments. Overall, these findings suggest that the autolysosomal compartment is a novel target of Na-modulated cell autonomous innate immunity. : ACT: actins; AKT: AKT serine/threonine kinase 1; ATG2A: autophagy related 2A; ATG4C: autophagy related 4C, cysteine peptidase; ATG7: autophagy related 7; ATG12: autophagy related 12; BECN1: beclin 1; BMDM: bone marrow-derived macrophages; BNIP3: BCL2/adenovirus E1B interacting protein 3; CFU: colony forming units; CM-HDCFDA: 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester; CTSB: cathepsin B; CYBB: cytochrome b-245 beta chain; DAPI: 4,6-diamidino-2-phenylindole; DMOG: dimethyloxallyl glycine; DPI: diphenyleneiodonium chloride; ; FDR: false discovery rate; GFP: green fluorescent protein; GSEA: gene set enrichment analysis; GO: gene ontology; HIF1A: hypoxia inducible factor 1, alpha subunit; HUGO: human genome organization; HS: high salt (+ 40 mM of NaCl to standard cell culture conditions); HSP90: heat shock 90 kDa proteins; LDH: lactate dehydrogenase; LPS: lipopolysaccharide; Lyz2/LysM: lysozyme 2; NFAT5/TonEBP: nuclear factor of activated T cells 5; MΦ: macrophages; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MFI: mean fluorescence intensity; MIC: minimum inhibitory concentration; MOI: multiplicity of infection; MTOR: mechanistic target of rapamycin kinase; NaCl: sodium chloride; NES: normalized enrichment score; n.s.: not significant; NO: nitric oxide; NOS2/iNOS: nitric oxide synthase 2, inducible; NS: normal salt; PCR: polymerase chain reaction; PGK1: phosphoglycerate kinase 1; PHOX: phagocyte oxidase; RFP: red fluorescent protein; RNA: ribonucleic acid; ROS: reactive oxygen species; sCFP3A: super cyan fluorescent protein 3A; SBFI: sodium-binding benzofuran isophthalate; SLC2A1/GLUT1: solute carrier family 2 (facilitated glucose transporter), member 1; SQSTM1/p62: sequestosome 1; ULK1: unc-51 like kinase 1; v-ATPase: vacuolar-type H-ATPase; WT: wild type.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/15548627.2019.1596483DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6844503PMC
November 2019

Limitation of TCA Cycle Intermediates Represents an Oxygen-Independent Nutritional Antibacterial Effector Mechanism of Macrophages.

Cell Rep 2019 03;26(13):3502-3510.e6

Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, 91054 Erlangen, Germany. Electronic address:

In hypoxic and inflamed tissues, oxygen (O)-dependent antimicrobial defenses are impaired due to a shortage of O. To gain insight into the mechanisms that control bacterial infection under hypoxic conditions, we infected macrophages with the obligate intracellular pathogen Coxiella burnetii, the causative agent of Q fever. Our experiments revealed that hypoxia impeded C. burnetii replication in a hypoxia-inducible factor (HIF) 1α-dependent manner. Mechanistically, under hypoxia, HIF1α impaired the activity of STAT3, which in turn reduced the intracellular level of TCA cycle intermediates, including citrate, and impeded C. burnetii replication in macrophages. However, bacterial viability was maintained, allowing the persistence of C. burnetii, which is a prerequisite for the development of chronic Q fever. This knowledge will open future research avenues on the pathogenesis of chronic Q fever. In addition, the regulation of TCA cycle metabolites by HIF1α represents a previously unappreciated mechanism of host defense against intracellular pathogens.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2019.02.103DOI Listing
March 2019