Identification of Potential miRNA-mRNA Regulatory Network in Denervated Muscular Atrophy by Bioinformatics Analysis

Abstract Muscle atrophy caused by long-term denervation leads to the loss of skeletal muscle mass and strength, resulting in a poor recovery of functional muscles and decreasing quality of life. Increasing differentially expressed microRNAs (DEMs) have been reported to be involved in the pathogenesis of denervated muscle atrophy. However, there is still insufficient evidence to explain the role of miRNAs and their target genes in skeletal muscle atrophy. Therefore, an integrative exploration of the miRNA-mRNA regulatory network in denervated muscle atrophy is necessary. A total of 21 (16 upregulated and 5 downregulated) DEMs were screened out in the GSE81914 dataset. Med1 was predicted and verified to be significantly upregulated, which may affect the process of denervated muscle atrophy by regulating mir-146b and mir-1949. 59 target genes were then predicted by submitting candidate DEMs to the miRNet database. GO and KEGG pathway enrichment analysis showed that target genes of DEMs were mainly enriched in the apoptotic process and PI3K/Akt signaling pathway. Through the PPI network construction, key modules and hub genes were obtained and potentially modulated by mir-29b, mir-132, and mir-133a. According to the qRT-PCR results, among the hub genes, Ctgf was significantly increased, which was consistent with the decreased mir-133a in denervated muscle atrophy. In the study, a potential miRNA-mRNA regulatory network was firstly constructed in denervated muscle atrophy. Two potential miRNA–mRNA pathways (miR-29b-COL1A1 and mir-133a-Ctgf) may provide new insight into the pathogenesis and treatment of denervated muscle atrophy.

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Identification of Potential miRNA-mRNA Regulatory Network in Denervated Muscular Atrophy by Bioinformatics Analysis

10.21203/rs.3.rs-864617/v1 ◽

2021 ◽

Author(s):

Jianhua Wang ◽

Yuhang Liu ◽

Yongming Zhang ◽

Bin Liu ◽

Zhijian Wei

Keyword(s):

Skeletal Muscle ◽

Muscle Atrophy ◽

Regulatory Network ◽

Target Genes ◽

Muscular Atrophy ◽

Enrichment Analysis ◽

Skeletal Muscle Atrophy ◽

Pathway Enrichment Analysis ◽

Denervated Muscle ◽

Hub Genes

Abstract Background Muscle atrophy caused by long-term denervation leads to the loss of skeletal muscle mass and strength, resulting in a poor recovery of functional muscles and decreasing quality of life. Increasing differentially expressed microRNAs (DEMs) have been reported to be involved in the pathogenesis of denervated muscle atrophy. However, there is still insufficient evidence to explain the role of miRNAs and their target genes in skeletal muscle atrophy. Therefore, an integrative exploration of the miRNA-mRNA regulatory network in denervated muscle atrophy is necessary. Results A total of 21 (16 upregulated and 5 downregulated) DEMs were screened out in the GSE81914 dataset. Med1 was predicted and verified to be significantly upregulated, which may affect the process of denervated muscle atrophy by regulating mir-146b and mir-1949. 59 target genes were then predicted by submitting candidate DEMs to the miRNet database. GO and KEGG pathway enrichment analysis showed that target genes of DEMs were mainly enriched in the apoptotic process and PI3K/Akt signaling pathway. Through the PPI network construction, key modules and hub genes were obtained and potentially modulated by mir-29b, mir-132, and mir-133a. According to the qRT-PCR results, among the hub genes, Ctgf was significantly increased, which was consistent with the decreased mir-133a in denervated muscle atrophy. Conclusions In the study, a potential miRNA-mRNA regulatory network was firstly constructed in denervated muscle atrophy. Two potential miRNA–mRNA pathways (miR-29b-COL1A1 and mir-133a-Ctgf) may provide new insight into the pathogenesis and treatment of denervated muscle atrophy.

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Identification of potential key genes and pathway linked with sporadic Creutzfeldt-Jakob disease based on integrated bioinformatics analyses

10.1101/2020.12.21.20248688 ◽

2020 ◽

Author(s):

Basavaraj Vastrad ◽

Chanabasayya Vastrad ◽

Iranna Kotturshetti

Keyword(s):

Regulatory Network ◽

Molecular Mechanisms ◽

Target Genes ◽

Enrichment Analysis ◽

Pathway Enrichment Analysis ◽

Ppi Network ◽

Hub Genes ◽

Bioinformatics Analyses ◽

Go Enrichment ◽

Jakob Disease

AbstractSporadic Creutzfeldt-Jakob disease (sCJD) is neurodegenerative disease also called prion disease linked with poor prognosis. The aim of the current study was to illuminate the underlying molecular mechanisms of sCJD. The mRNA microarray dataset GSE124571 was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were screened. Pathway and GO enrichment analyses of DEGs were performed. Furthermore, the protein-protein interaction (PPI) network was predicted using the IntAct Molecular Interaction Database and visualized with Cytoscape software. In addition, hub genes and important modules were selected based on the network. Finally, we constructed target genes - miRNA regulatory network and target genes - TF regulatory network. Hub genes were validated. A total of 891 DEGs 448 of these DEGs presented significant up regulated, and the remaining 443 down regulated were obtained. Pathway enrichment analysis indicated that up regulated genes were mainly linked with glutamine degradation/glutamate biosynthesis, while the down regulated genes were involved in melatonin degradation. GO enrichment analyses indicated that up regulated genes were mainly linked with chemical synaptic transmission, while the down regulated genes were involved in regulation of immune system process. hub and target genes were selected from the PPI network, modules, and target genes - miRNA regulatory network and target genes - TF regulatory network namely YWHAZ, GABARAPL1, EZR, CEBPA, HSPB8, TUBB2A and CDK14. The current study sheds light on the molecular mechanisms of sCJD and may provide molecular targets and diagnostic biomarkers for sCJD.

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Exosomal miR-199a-5p Inhibits Tumorigenesis and Angiogenesis by Targeting VEGFA in Osteosarcoma

10.21203/rs.3.rs-912512/v1 ◽

2021 ◽

Author(s):

Lu Zhang ◽

Hongxin Cao ◽

Guanghui Gu ◽

Dehui Hou ◽

Yunhao You ◽

...

Keyword(s):

Molecular Mechanisms ◽

Target Genes ◽

Enrichment Analysis ◽

Luciferase Reporter ◽

Pathway Enrichment Analysis ◽

Osteosarcoma Cell ◽

Plasma Samples ◽

Osteosarcoma Cells ◽

Hub Genes

Abstract Background: Osteosarcoma (OS) is the most common primary bone malignancy in children and adolescents. microRNAs have been found to play a vital role in tumor angiogenesis. Here, we investigated the effects of miR-199a-5p on tumor growth and angiogenesis in osteosarcoma. Furthermore, the underlying molecular mechanisms and signaling pathways were explored.Methods: The datasets were extracted from the Gene Expression Omnibus and the differentially expressed miRNAs (DEmiRNAs) were screened out by the GEO2R online platform. The potential target genes were predicted using the miRTarBase database. The predicted target genes were further analyzed by Gene Ontology and pathway enrichment analysis and a regulatory network of DEmiRNAs and their target genes was constructed. In addition, the effects of osteosarcoma cell derived exosomal miR-199a-5p on the proliferation, migration and neovascularization of HUVECs were evaluated by conducting EdU assays, Transwell experiments and tube formation assays. A dual-luciferase reporter assay was performed to detect whether VEGFA was the direct target of miR-199a-5p. Furthermore, in vivo xenograft models were established to further investigate the intrinsic role of miR-199a-5p in osteosarcoma tumorigenesis and angiogenesis. Results: A total of 149 DE-miRNAs were screened out, including 136 upregulated miRNAs and 13 downregulated miRNAs in human osteosarcoma plasma samples compared with normal plasma samples. A total of 1313 target genes of the top three upregulated and downregulated miRNAs were predicted. In the PPI network, the top 10 hub nodes with higher degrees were identified as hub genes, such as TP53 and VEGFA. By constructing the miRNA-hub gene network, we found that most of hub genes could be potentially modulated by miR-663a, miR-199a-5p and miR-223-3p. In addition, we found that the expression level of miR-199a-5p in exosomes derived from osteosarcoma cells was remarkably higher than the osteosarcoma cells, and the exosomes derived from osteosarcoma cells were transported to HUVECs. Overexpression of miR-199a-5p could significantly inhibited HUVEC proliferation, migration and neovascularization, whereas downregulation of miR-199a-5p expression exerted the opposite effect. Moreover, the in vivo results verified that overexpression of miR-199a-5p in osteosarcoma cells could suppress the growth and angiogenesis of tumors. Conclusion: Our results demonstrated that miR-199a-5p could be transported from osteosarcoma cells to HUVECs through exosomes, subsequently targeting VEGFA and inhibiting the growth and angiogenesis of osteosarcoma. Therefore, miR-199a-5p may act as a biomarker in the diagnosis and treatment of osteosarcoma.

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Identification of Potential miRNA-mRNA Regulatory Network Contributing to Parkinson’s Disease

10.21203/rs.3.rs-779087/v1 ◽

2021 ◽

Author(s):

Xi Yin ◽

Miao Wang ◽

Wei Wang ◽

Tong Chen ◽

Ge Song ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Regulatory Network ◽

Enrichment Analysis ◽

Functional Enrichment ◽

Pathway Enrichment Analysis ◽

Hub Genes ◽

Rab Protein ◽

Healthy Donors ◽

Geo Database

Abstract Parkinson’s disease (PD) is a common neurodegenerative disease and the mechanism underlying PD pathogenesis is incompletely understood. Increasing evidence indicates that microRNA (miRNA) plays critical regulatory role in the pathogenesis of PD. This study aimed to determine the miRNA-mRNA regulatory network for PD. The differentially expressed miRNAs (DEmis) and genes (DEGs) between PD patients and healthy donors were screened from miRNA dataset GSE16658 and mRNA dataset GSE100054 downloaded from the Gene Expression Omnibus (GEO) database. Target genes of the DEmis were selected when predicted by 3 or 4 online databases and overlapped with DEGs from GSE100054. Next, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was conducted by Database for Annotation, Visualization and Integrated Discovery (DAVID) and Metascape analytic tool. The correlation between the screened genes and PD was evaluated by the online tool Comparative Toxicogenomics Database (CTD). The protein-protein interactions (PPI) network was built by STRING platform. Finally, we testify the expression of members of the miRNA-mRNA regulatory network in the blood samples collected from PD patients and healthy donors by using qRT-PCR. 1505 upregulated and 1302 downregulated DEGs, 77 upregulated DEmis and 112 downregulated DEmis were preliminarily screened from GEO database. Through further functional enrichment analysis, 10 PD-related hub genes were selected, including RAC1, IRS2, LEPR, PPARGC1A, CAMKK2, RAB10, RAB13, RAB27B, RAB11A and JAK2, which were mainly involved in Rab protein signaling transduction, AMPK signaling pathway and signaling by Leptin. The miRNA-mRNA regulatory network was constructed with 10 hub genes and their interacting miRNAs overlapped with DEmis, including miR-30e-5p, miR-142-3p, miR-101-3p, miR-32-3p, miR-508-5p, miR-642a-5p, miR-19a-3p and miR-21-5p. Analysis on clinical samples verified significant upregulation of LEPR and downregulation of miR-101-3p in PD patients compared with healthy donors. In the study, the potential miRNA-mRNA regulatory network was constructed in PD, which may provide novel insight into pathogenesis and treatment of PD.

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MicroRNA 322 Aggravates Dexamethasone-Induced Muscle Atrophy by Targeting IGF1R and INSR

International Journal of Molecular Sciences ◽

10.3390/ijms21031111 ◽

2020 ◽

Vol 21 (3) ◽

pp. 1111 ◽

Cited By ~ 1

Author(s):

Hongwei Geng ◽

Qinglong Song ◽

Yunyun Cheng ◽

Haoyang Li ◽

Rui Yang ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Atrophy ◽

Target Genes ◽

Immunosuppressive Agent ◽

Skeletal Muscle Atrophy ◽

Luciferase Reporter ◽

C2c12 Myotubes ◽

High Dose ◽

Reporter Assays ◽

Underlying Mechanisms

Dexamethasone (Dex) has been widely used as a potent anti-inflammatory, antishock, and immunosuppressive agent. However, high dose or long-term use of Dex is accompanied by side effects including skeletal muscle atrophy, whose underlying mechanisms remain incompletely understood. A number of microRNAs (miRNAs) have been shown to play key roles in skeletal muscle atrophy. Previous studies showed significantly increased miR-322 expression in Dex-treated C2C12 myotubes. In our study, the glucocorticoid receptor (GR) was required for Dex to increase miR-322 expression in C2C12 myotubes. miR-322 mimic or miR-322 inhibitor was used for regulating the expression of miR-322. Insulin-like growth factor 1 receptor (IGF1R) and insulin receptor (INSR) were identified as target genes of miR-322 using luciferase reporter assays and played key roles in Dex-induced muscle atrophy. miR-322 overexpression promoted atrophy in Dex-treated C2C12 myotubes and the gastrocnemius muscles of mice. Conversely, miR-322 inhibition showed the opposite effects. These data suggested that miR-322 contributes to Dex-induced muscle atrophy via targeting of IGF1R and INSR. Furthermore, miR-322 might be a potential target to counter Dex-induced muscle atrophy. miR-322 inhibition might also represent a therapeutic approach for Dex-induced muscle atrophy.

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Ficus carica L. Attenuates Denervated Skeletal Muscle Atrophy via PPARα/NF-κB Pathway

Frontiers in Physiology ◽

10.3389/fphys.2020.580223 ◽

2020 ◽

Vol 11 ◽

Author(s):

Junxi Dai ◽

Yaoxian Xiang ◽

Da Fu ◽

Lei Xu ◽

Junjian Jiang ◽

...

Keyword(s):

Skeletal Muscle ◽

Peripheral Nerve ◽

Signaling Pathway ◽

Nerve Injury ◽

Muscle Atrophy ◽

Peripheral Nerve Injury ◽

Ficus Carica ◽

Differentially Expressed ◽

Skeletal Muscle Atrophy ◽

Denervated Muscle

Treatment options for denervated skeletal muscle atrophy are limited, in part because the underlying molecular mechanisms are not well understood. Unlike previous transcriptomics studies conducted in rodent models of peripheral nerve injury, in the present study, we performed high-throughput sequencing with denervated atrophic biceps muscle and normal (non-denervated) sternocleidomastoid muscle samples obtained from four brachial plexus injury (BPI) patients. We also investigated whether Ficus carica L. (FCL.) extract can suppress denervated muscle atrophy in a mouse model, along with the mechanism of action. We identified 1471 genes that were differentially expressed between clinical specimens of atrophic and normal muscle, including 771 that were downregulated and 700 that were upregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that the differentially expressed genes were mainly enriched in the GO terms “structural constituent of muscle,” “Z disc,” “M band,” and “striated muscle contraction,” as well as “Cell adhesion molecules,” “Glycolysis/Gluconeogenesis,” “Peroxisome proliferator-activated receptor alpha (PPARα) signaling pathway,” and “P53 signaling pathway.” In experiments using mice, the reduction in wet weight and myofiber diameter in denervated muscle was improved by FCL. extract compared to saline administration, which was accompanied by downregulation of the proinflammatory cytokines interleukin (IL)-1β and IL-6. Moreover, although both denervated groups showed increased nuclear factor (NF)-κB activation and PPARα expression, the degree of NF-κB activation was lower while PPARα and inhibitor of NF-κB IκBα expression was higher in FCL. extract-treated mice. Thus, FCL. extract suppresses denervation-induced inflammation and attenuates muscle atrophy by enhancing PPARα expression and inhibiting NF-κB activation. These findings suggest that FCL. extract has therapeutic potential for preventing denervation-induced muscle atrophy caused by peripheral nerve injury or disease.

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Differentially expressed circulating miRNAs in postmenopausal osteoporosis: a meta-analysis

Bioscience Reports ◽

10.1042/bsr20190667 ◽

2019 ◽

Vol 39 (5) ◽

Cited By ~ 5

Author(s):

Elif Pala ◽

Tuba Denkçeken

Keyword(s):

Postmenopausal Osteoporosis ◽

Signaling Pathway ◽

Target Genes ◽

Meta Analysis ◽

Adherens Junction ◽

Enrichment Analysis ◽

Rank Aggregation ◽

Cochrane Library ◽

Pathway Enrichment Analysis ◽

Hub Genes

AbstractMicroRNAs (miRNAs) have been proven to play a crucial role in postmenopausal osteoporosis (PMO), and studies on their diagnostic value have been increasing. In our study, we aim to identify the key miRNAs in the PMO that might be potential biomarkers. A comprehensive systematic literature search was conducted by searching PubMed, Web of Science, Embase and Cochrane Library databases. In the total of 16 independent miRNA expression studies which contained 327 PMO patients and 328 postmenopausal (PM) healthy control samples, miRNAs were evaluated by using robust rank aggregation (RRA) method. A statistically significant meta-signature of up-regulated hsa-miR-133a-3p (P = 1.38e−03) was determined. Then bioinformatics analysis to recruit putative target genes prediction of hsa-miR-133a-3p and pathway enrichment analysis to reveal what biological processes this miRNA may affect were conducted. It was indicated that pathways were commonly associated with adrenergic signaling in cardiomyocytes, adherens junction, PI3K-Akt signaling pathway and AMPK signaling pathway. Furthermore, STRING and Cytoscape tools were used to visualize the interactions between target genes of hsa-miR-133a-3p. Six genes were detected as hub genes among 576 targets which were CDC42, RHOA, EGFR, VAMP2, PIK3R2 and FN1. After Kyoto Encyclopedia of Genes and Genomes pathway analysis, it was detected that these hub genes were mostly enriched in signaling pathways and cancer. In this meta-analysis, it is stated that circulating hsa-miR-133a-3p may serve as a potential non-invasive biomarker and therapeutic target in PMO.

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Investigation of candidate genes and mechanisms underlying obesity associated type 2 diabetes mellitus using bioinformatics analysis and screening of small drug molecules

BMC Endocrine Disorders ◽

10.1186/s12902-021-00718-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

G. Prashanth ◽

Basavaraj Vastrad ◽

Anandkumar Tengli ◽

Chanabasayya Vastrad ◽

Iranna Kotturshetti

Keyword(s):

Diabetes Mellitus ◽

Type 2 Diabetes ◽

Type 2 Diabetes Mellitus ◽

Target Genes ◽

Enrichment Analysis ◽

Pathway Enrichment Analysis ◽

Hub Genes ◽

Pathway Enrichment ◽

Drug Molecules

Abstract Background Obesity associated type 2 diabetes mellitus is a metabolic disorder ; however, the etiology of obesity associated type 2 diabetes mellitus remains largely unknown. There is an urgent need to further broaden the understanding of the molecular mechanism associated in obesity associated type 2 diabetes mellitus. Methods To screen the differentially expressed genes (DEGs) that might play essential roles in obesity associated type 2 diabetes mellitus, the publicly available expression profiling by high throughput sequencing data (GSE143319) was downloaded and screened for DEGs. Then, Gene Ontology (GO) and REACTOME pathway enrichment analysis were performed. The protein - protein interaction network, miRNA - target genes regulatory network and TF-target gene regulatory network were constructed and analyzed for identification of hub and target genes. The hub genes were validated by receiver operating characteristic (ROC) curve analysis and RT- PCR analysis. Finally, a molecular docking study was performed on over expressed proteins to predict the target small drug molecules. Results A total of 820 DEGs were identified between healthy obese and metabolically unhealthy obese, among 409 up regulated and 411 down regulated genes. The GO enrichment analysis results showed that these DEGs were significantly enriched in ion transmembrane transport, intrinsic component of plasma membrane, transferase activity, transferring phosphorus-containing groups, cell adhesion, integral component of plasma membrane and signaling receptor binding, whereas, the REACTOME pathway enrichment analysis results showed that these DEGs were significantly enriched in integration of energy metabolism and extracellular matrix organization. The hub genes CEBPD, TP73, ESR2, TAB1, MAP 3K5, FN1, UBD, RUNX1, PIK3R2 and TNF, which might play an essential role in obesity associated type 2 diabetes mellitus was further screened. Conclusions The present study could deepen the understanding of the molecular mechanism of obesity associated type 2 diabetes mellitus, which could be useful in developing therapeutic targets for obesity associated type 2 diabetes mellitus.

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In silico Identification of 10 Hub Genes and an miRNA–mRNA Regulatory Network in Acute Kawasaki Disease

Frontiers in Genetics ◽

10.3389/fgene.2021.585058 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jin Ma ◽

Huan Gui ◽

Yunjia Tang ◽

Yueyue Ding ◽

Guanghui Qian ◽

...

Keyword(s):

Kawasaki Disease ◽

Signaling Pathway ◽

Regulatory Network ◽

Molecular Mechanisms ◽

Target Genes ◽

Unknown Etiology ◽

Pathway Enrichment Analysis ◽

Ppi Network ◽

Hub Genes ◽

Ppi Networks

Kawasaki disease (KD) causes acute systemic vasculitis and has unknown etiology. Since the acute stage of KD is the most relevant, the aim of the present study was to identify hub genes in acute KD by bioinformatics analysis. We also aimed at constructing microRNA (miRNA)–messenger RNA (mRNA) regulatory networks associated with acute KD based on previously identified differentially expressed miRNAs (DE-miRNAs). DE-mRNAs in acute KD patients were screened using the mRNA expression profile data of GSE18606 from the Gene Expression Omnibus. The functional and pathway enrichment analysis of DE-mRNAs were performed with the DAVID database. Target genes of DE-miRNAs were predicted using the miRWalk database and their intersection with DE-mRNAs was obtained. From a protein–protein interaction (PPI) network established by the STRING database, Cytoscape software identified hub genes with the two topological analysis methods maximal clique centrality and Degree algorithm to construct a miRNA-hub gene network. A total of 1,063 DE-mRNAs were identified between acute KD and healthy individuals, 472 upregulated and 591 downregulated. The constructed PPI network with these DE-mRNAs identified 38 hub genes mostly enriched in pathways related to systemic lupus erythematosus, alcoholism, viral carcinogenesis, osteoclast differentiation, adipocytokine signaling pathway and tumor necrosis factor signaling pathway. Target genes were predicted for the up-regulated and down-regulated DE-miRNAs, 10,203, and 5,310, respectively. Subsequently, 355, and 130 overlapping target DE-mRNAs were obtained for upregulated and downregulated DE-miRNAs, respectively. PPI networks with these target DE-mRNAs produced 15 hub genes, six down-regulated and nine upregulated hub genes. Among these, ten genes (ATM, MDC1, CD59, CD177, TRPM2, FCAR, TSPAN14, LILRB2, SIRPA, and STAT3) were identified as hub genes in the PPI network of DE-mRNAs. Finally, we constructed the regulatory network of DE-miRNAs and hub genes, which suggested potential modulation of most hub genes by hsa-miR-4443 and hsa-miR-6510-5p. SP1 was predicted to potentially regulate most of DE-miRNAs. In conclusion, several hub genes are associated with acute KD. An miRNA–mRNA regulatory network potentially relevant for acute KD pathogenesis provides new insights into the underlying molecular mechanisms of acute KD. The latter may contribute to the diagnosis and treatment of acute KD.

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Metronidazole Causes Skeletal Muscle Atrophy and Modulates Muscle Chronometabolism

International Journal of Molecular Sciences ◽

10.3390/ijms19082418 ◽

2018 ◽

Vol 19 (8) ◽

pp. 2418 ◽

Cited By ~ 11

Author(s):

Ravikumar Manickam ◽

Hui Oh ◽

Chek Tan ◽

Eeswari Paramalingam ◽

Walter Wahli

Keyword(s):

Skeletal Muscle ◽

Muscle Atrophy ◽

Metabolic Regulation ◽

Target Genes ◽

Clock Genes ◽

Tibialis Anterior Muscle ◽

Skeletal Muscle Atrophy ◽

Muscle Weight ◽

Expression Of Genes ◽

Specific Pathogen

Antibiotics lead to increased susceptibility to colonization by pathogenic organisms, with different effects on the host-microbiota relationship. Here, we show that metronidazole treatment of specific pathogen-free (SPF) mice results in a significant increase of the bacterial phylum Proteobacteria in fecal pellets. Furthermore, metronidazole in SPF mice decreases hind limb muscle weight and results in smaller fibers in the tibialis anterior muscle. In the gastrocnemius muscle, metronidazole causes upregulation of Hdac4, myogenin, MuRF1, and atrogin1, which are implicated in skeletal muscle neurogenic atrophy. Metronidazole in SPF mice also upregulates skeletal muscle FoxO3, described as involved in apoptosis and muscle regeneration. Of note, alteration of the gut microbiota results in increased expression of the muscle core clock and effector genes Cry2, Ror-β, and E4BP4. PPARγ and one of its important target genes, adiponectin, are also upregulated by metronidazole. Metronidazole in germ-free (GF) mice increases the expression of other core clock genes, such as Bmal1 and Per2, as well as the metabolic regulators FoxO1 and Pdk4, suggesting a microbiota-independent pharmacologic effect. In conclusion, metronidazole in SPF mice results in skeletal muscle atrophy and changes the expression of genes involved in the muscle peripheral circadian rhythm machinery and metabolic regulation.

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