Dataset Information

Epigenetic regulation of NfatC1 transcription and osteoclastogenesis by nicotinamide phosphoribosyl transferase in the pathogenesis of arthritis.

ABSTRACT: Nicotinamide phosphoribosyltransferase (NAMPT) functions in NAD synthesis, apoptosis, and inflammation. Dysregulation of NAMPT has been associated with several inflammatory diseases, including rheumatoid arthritis (RA). The purpose of this study was to investigate NAMPT's role in arthritis using mouse and cellular models. Collagen-induced arthritis (CIA) in DBA/1J Nampt +/- mice was evaluated by ELISA, micro-CT, and RNA-sequencing (RNA-seq). In vitro Nampt loss-of-function and gain-of-function studies on osteoclastogenesis were examined by TRAP staining, nascent RNA capture, luciferase reporter assays, and ChIP-PCR. Nampt-deficient mice presented with suppressed inflammatory bone destruction and disease progression in a CIA mouse model. Nampt expression was required for the epigenetic regulation of the Nfatc1 promoter and osteoclastogenesis. Finally, RNA-seq identified 690 differentially expressed genes in whole ankle joints which associated (P?

SUBMITTER: Li X

PROVIDER: S-EPMC6365567 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Epigenetic regulation of NfatC1 transcription and osteoclastogenesis by nicotinamide phosphoribosyl transferase in the pathogenesis of arthritis.

Li Xuanan X Islam Shamima S Xiong Min M Nsumu Ndona N NN Lee Mark W MW Zhang Li Qin LQ Ueki Yasuyoshi Y Heruth Daniel P DP Lei Guanghua G Ye Shui Qing SQ

Cell death discovery 20190206

Nicotinamide phosphoribosyltransferase (NAMPT) functions in NAD synthesis, apoptosis, and inflammation. Dysregulation of NAMPT has been associated with several inflammatory diseases, including rheumatoid arthritis (RA). The purpose of this study was to investigate NAMPT's role in arthritis using mouse and cellular models. Collagen-induced arthritis (CIA) in DBA/1J <i>Nampt</i> <sup>+/-</sup> mice was evaluated by ELISA, micro-CT, and RNA-sequencing (RNA-seq). In vitro Nampt loss-of-function and ...[more]

PMID: 30774990

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Project description:In inflammatory arthritis, the dysregulation of osteoclast activity by proinflammatory cytokines, including TNF, interferes with bone remodeling during inflammation through Ca2+-dependent mechanisms causing pathological bone loss. Ca2+-dependent CREB/c-fos activation via Ca2+-calmodulin kinase IV (CaMKIV) induces transcriptional regulation of osteoclast-specific genes via NFATc1, which facilitate bone resorption. In leukocytes, Ca2+ regulation of NFAT-dependent gene expression oftentimes involves the activity of the Ca2+-activated K+ channel KCa3.1. In this study, we evaluate KCa3.1 as a modulator of Ca2+-induced NFAT-dependent osteoclast differentiation in inflammatory bone loss. Microarray analysis of receptor activator of NF-?B ligand (RANKL)-activated murine bone marrow macrophage (BMM) cultures revealed unique upregulation of KCa3.1 during osteoclastogenesis. The expression of KCa3.1 in vivo was confirmed by immunofluorescence staining on multinucleated cells at the bone surface of inflamed mouse joints. Experiments on in vitro BMM cultures revealed that KCa3.1-/- and TRAM-34 treatment significantly reduced the expression of osteoclast-specific genes (p < 0.05) alongside decreased osteoclast formation (p < 0.0001) in inflammatory (RANKL+TNF) and noninflammatory (RANKL) conditions. In particular, live cell Ca2+ imaging and Western blot analysis showed that TRAM-34 pretreatment decreased transient RANKL-induced Ca2+ amplitudes in BMMs by ?50% (p < 0.0001) and prevented phosphorylation of CaMKIV. KCa3.1-/- reduced RANKL+/-TNF-stimulated phosphorylation of CREB and expression of c-fos in BMMs (p < 0.01), culminating in decreased NFATc1 protein expression and transcriptional activity (p < 0.01). These data indicate that KCa3.1 regulates Ca2+-dependent NFATc1 expression via CaMKIV/CREB during inflammatory osteoclastogenesis in the presence of TNF, corroborating its role as a target candidate for the treatment of bone erosion in inflammatory arthritis.

Project description:Mice overexpressing NAMPT in skeletal muscle (NamptTg mice) develop higher exercise endurance and maximal aerobic capacity (VO2max) following voluntary exercise training compared to wild-type (WT) mice. Here, we aimed to investigate the mechanisms underlying by determining skeletal muscle mitochondrial respiratory capacity in NamptTg and WT mice. Body weight and body composition, tissue weight (gastrocnemius, quadriceps, soleus, heart, liver, and epididymal white adipose tissue), skeletal muscle and liver glycogen content, VO2max, skeletal muscle mitochondrial respiratory capacity (measured by high-resolution respirometry), skeletal muscle gene expression (measured by microarray and qPCR), and skeletal muscle protein content (measured by Western blot) were determined following 6 weeks of voluntary exercise training (access to running wheel) in 13-week-old male NamptTg (exercised NamptTg) mice and WT (exercised WT) mice. Daily running distance and running time during the voluntary exercise training protocol were recorded. Daily running distance (p = 0.51) and running time (p = 0.85) were not significantly different between exercised NamptTg mice and exercised WT mice. VO2max was higher in exercised NamptTg mice compared to exercised WT mice (p = 0.02). Body weight (p = 0.92), fat mass (p = 0.49), lean mass (p = 0.91), tissue weight (all p > 0.05), and skeletal muscle (p = 0.72) and liver (p = 0.94) glycogen content were not significantly different between exercised NamptTg mice and exercised WT mice. Complex I oxidative phosphorylation (OXPHOS) respiratory capacity supported by fatty acid substrates (p < 0.01), maximal (complex I+II) OXPHOS respiratory capacity supported by glycolytic (p = 0.02) and fatty acid (p < 0.01) substrates, and maximal uncoupled respiratory capacity supported by fatty acid substrates (p < 0.01) was higher in exercised NamptTg mice compared to exercised WT mice. Transcriptomic analyses revealed differential expression for genes involved in oxidative metabolism in exercised NamptTg mice compared to exercised WT mice, specifically, enrichment for the gene set related to the SIRT3-mediated signaling pathway. SIRT3 protein content correlated with NAMPT protein content (r = 0.61, p = 0.04). In conclusion, NamptTg mice develop higher exercise capacity following voluntary exercise training compared to WT mice, which is paralleled by higher mitochondrial respiratory capacity in skeletal muscle. The changes in SIRT3 targets suggest that these effects are due to remodeling of mitochondrial function.

Dataset Information

Epigenetic regulation of NfatC1 transcription and osteoclastogenesis by nicotinamide phosphoribosyl transferase in the pathogenesis of arthritis.

Publications

Epigenetic regulation of NfatC1 transcription and osteoclastogenesis by nicotinamide phosphoribosyl transferase in the pathogenesis of arthritis.

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