Department of Stomatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
National Clinical Research Center for Metabolic Diseases, Hunan Provincial Key Laboratory of Metabolic Bone Diseases, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
PLoS Negl Trop Dis. 2022 May 2;16(5):e0010379. doi: 10.1371/journal.pntd.0010379. eCollection 2022 May.
Bone formation and loss are the characteristic clinical manifestations of leprosy, but the mechanisms underlying the bone remodeling with Mycobacterium leprae (M. leprae) infection are unclear.
METHODOLOGY/PRINCIPAL FINDINGS: Osteocytes may have a role through regulating the differentiation of osteogenic lineages. To investigate osteocyte-related mechanisms in leprosy, we treated osteocyte-like cell with N-glycosylated muramyl dipeptide (N.g MDP). RNA-seq analysis showed 724 differentially expressed messenger RNAs (mRNAs) and 724 differentially expressed circular RNA (circRNAs). Of these, we filtered through eight osteogenic-related differentially expressed genes, according to the characteristic of competing endogenous RNA, PubMed databases, and bioinformatic analysis, including TargetScan, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes. Based on these results, we built a circRNA-microRNA (miRNA)-mRNA triple network. Quantitative reverse-transcription polymerase chain reaction and western blots analyses confirmed decreased Clock expression in osteocyte-like cell, while increased in bone mesenchymal stem cells (BMSCs), implicating a crucial factor in osteogenic differentiation. Immunohistochemistry showed obviously increased expression of CLOCK protein in BMSCs and osteoblasts in N.g MDP-treated mice, but decreased expression in osteocytes.
CONCLUSIONS/SIGNIFICANCE: This analytical method provided a basis for the relationship between N.g MDP and remodeling in osteocytes, and the circRNA-miRNA-mRNA triple network may offer a new target for leprosy therapeutics.
骨质形成和丢失是麻风病的特征性临床表现，但麻风分枝杆菌（M. leprae）感染导致骨质重塑的机制尚不清楚。
方法/主要发现：破骨细胞可能通过调节成骨谱系的分化来发挥作用。为了研究破骨细胞相关的麻风病发病机制，我们用 N-糖基化的胞壁酰二肽（N.g MDP）处理成骨样细胞。RNA-seq 分析显示有 724 个差异表达的信使 RNA（mRNA）和 724 个差异表达的环状 RNA（circRNA）。根据竞争内源性 RNA 的特征、PubMed 数据库和生物信息学分析（包括 TargetScan、基因本体论和京都基因与基因组百科全书），我们筛选出了 8 个与成骨相关的差异表达基因。基于这些结果，我们构建了 circRNA-miRNA-mRNA 三重网络。定量逆转录聚合酶链反应和 Western blot 分析证实，成骨样细胞中 Clock 表达减少，而在骨髓间充质干细胞（BMSCs）中表达增加，这表明 Clock 是成骨分化的关键因素。免疫组织化学显示，N.g MDP 处理的小鼠 BMSCs 和成骨细胞中 CLOCK 蛋白表达明显增加，而在破骨细胞中表达减少。
结论/意义：该分析方法为 N.g MDP 与成骨细胞重塑之间的关系提供了依据，circRNA-miRNA-mRNA 三重网络可能为麻风病的治疗提供新的靶点。
