Identification of a novel immune-related transcriptional regulatory network in sarcopenia.

BACKGROUND: Sarcopenia is highly prevalent in elderly individuals and has a significant adverse effect on their physical health and quality of life, but the mechanisms remain unclear. Studies have indicated that transcription factors (TFs) and the immune microenvironment play a vital role in skeletal muscle atrophy. METHODS: RNA-seq data of 40 muscle samples were downloaded from the GEO database. Then, differentially expressed genes (DEGs), TFs(DETFs), pathways(DEPs), and the expression of immune gene sets were identified with limma, edgeR, GO, KEGG, ORA, GSVA, and ssGSEA. Furthermore, the results above were integrated into coexpression analysis by Pearson correlation analysis (PCA). Significant coexpression patterns were used to construct the immune-related transcriptional regulatory network by Cytoscape and potential medicine targeting the network was screened by Connectivity Map. Finally, the regulatory mechanisms and RNA expression of DEGs and DETFs were identified by multiple online databases and RT‒qPCR. RESULTS: We screened 808 DEGs (log2 fold change (FC) > 1 or < - 1, p < 0.05), 4 DETFs (log2FC > 0.7 or < - 0.7, p < 0.05), 304 DEPs (enrichment scores (ES) > 1 or < - 1, p < 0.05), and 1208 differentially expressed immune genes sets (DEIGSs) (p < 0.01). Based on the results of PCA (correlation coefficient (CC) > 0.4 or < - 0.4, p < 0.01), we then structured an immune-related network with 4 DETFs, 9 final DEGs, 11 final DEPs, and 6 final DEIGSs. Combining the results of online databases and in vitro experiments, we found that PAX5-SERPINA5-PI3K/Akt (CC ≤ 0.444, p ≤ 0.004) was a potential transcriptional regulation axis, and B cells (R = 0.437, p = 0.005) may play a vital role in this signal transduction. Finally, the compound of trichostatin A (enrichment = -0.365, specificity = 0.4257, p < 0.0001) might be a potential medicine for sarcopenia based on the PubChem database and the result of the literature review. CONCLUSIONS: We first identified immune-related transcriptional regulatory network with high-throughput RNA-seq data in sarcopenia. We hypothesized that PAX5-SERPIAN5-PI3K/Akt axis is a potential mechanism in sarcopenia and that B cells may play a vital role in this signal transduction. In addition, trichostatin A might be a potential medicine for sarcopenia.

[Treatment of AO/OTA type 31-A3 intertrochanteric fracture with proximal femoral nail antirotation combined with mini plate reconstruction of lateral femoral wall].

OBJECTIVE: To explore the effectiveness of proximal femoral nail antirotation (PFNA) combined with mini plate for reconstruction of lateral femoral wall in the treatment of type AO/Orthopaedic Trauma Association (AO/OTA) type 31-A3 intertrochanteric fracture. METHODS: The clinical data of 70 elderly patients with AO/OTA type 31-A3 intertrochanteric fracture treated between January 2013 and January 2018 were retrospectively analyzed. They were divided into group A (PFNA alone, 35 cases) and group B (PFNA combined with mini plate reconstruction of lateral femoral wall, 35 cases). There was no significant difference in the general data of gender, age, side, cause of injury, time from injury to operation between the two groups ( P>0.05). The operation time, intraoperative blood loss, fracture healing time, postoperative complications, and the tip apex distance (TAD) at 2 months after operation were recorded and compared between the two groups. Harris hip score was used to evaluate the function at 12 months after operation. RESULTS: Both groups were followed up 9-21 months, with an average of 16.6 months. The operation time and intraoperative blood loss in group A were significantly less than those in group B ( P<0.05); there was no significant difference in TAD between the two groups at 2 months after operation ( t=0.096, P=0.462). There were 5 complications (14.3%) occurred in group A, including 2 cases of blade perforating from the hip joint, 2 cases of screw back out, and 1 case of bone nonunion; only 1 case (2.9%) in group B had screw back out after operation; there was no significant difference in the incidence of complications between the two groups ( χ 2=2.917, P=0.088). All the fracture healed in group B, and 1 patient in group A suffered bone nonunion and eventually main nail fracture. The healing time of fracture in group A [(15.6±2.7) weeks] was significantly longer than that in group B [(12.5±2.5) weeks], showing significant difference ( t=2.064, P=0.023). At 12 months after operation, according to Harris score, the results were excellent in 5 cases, good in 9 cases, fair in 13 cases, and poor in 8 cases in group A, the qualified rate (Harris score>70) was 77.14%; and the results were excellent in 7 cases, good in 11 cases, fair in 16 cases, and poor in 1 case in group B, the qualified rate was 97.14%; there was significant difference in the qualified rate between the two groups ( χ 2=6.248, P=0.012). CONCLUSION: Compared with PFNA alone, the treatment of AO/OTA type 31-A3 intertrochanteric fracture with PFNA combined with mini plate reconstruction of lateral femoral wall can significantly reduce postoperative complications, promote fracture healing, and improve functional recovery of patients after operation.

MicroRNA­218 promotes prostaglandin E2 to inhibit osteogenic differentiation in synovial mesenchymal stem cells by targeting 15­hydroxyprostaglandin dehydrogenase [NAD(+)].

The chondrogenic differentiation of synovial mesenchymal stem cells (SMSCs) is regulated by essential transcription factors and signaling cascades. However, the precise mechanisms involved in this process remain unclear. MicroRNAs (miRs/miRNAs) are undersized non­coding RNAs responsible for the post­transcriptional regulation of gene expression, by binding to the 3'­untranslated regions (3'­UTRs) of their target mRNAs. miRNAs may constitute a promising tool to regulate SMSC differentiation and to advance the controlled differentiation of SMSCs in therapeutic applications. The aim of the present study was to examine the role of miR­218 in SMSC differentiation towards chondrocytes. The present study comparatively analyzed the expression profile of known miRNAs and specific target genes in SMSCs between early and late differentiation stages. Western blotting and reverse transcription­quantitative polymerase chain reaction analysis of gene expression demonstrated the upregulation of 15­hydroxyprostaglandin dehydrogenase [NAD(+)] (15­HPGD), prostaglandin E2 (PGE2) and rate limiting enzymes responsible for the synthesis of PGE2 precursors throughout chondrogenesis. Through correlation analysis, it was observed that there was a significant association between miR­128, 15­HPGD gene expression, 15­HPGD protein expression and microsomal prostaglandin E synthase 1. Further experiments demonstrated that miR­218 decreased PGE2 concentration by binding to the 3'­UTR of 15­HPGD. Using an immunofluorescence reporting system, it was observed that miR­218 regulated the expression of 15­HPGD during the differentiation of SMSCs into cartilage, and subsequently inhibited osteogenesis during chondrogenesis by acting on the 3'UTR of 15­HPGD. Therefore, miR­218 may be an important regulator targeting osteogenic factors and modulating cartilage formation and differentiation. The results of the present study provided a novel insight beneficial to cellular manipulation methods during cartilage regeneration, and in cartilage tissue engineering research.

Ossification of the posterior longitudinal ligament related genes identification using microarray gene expression profiling and bioinformatics analysis.

Ossification of the posterior longitudinal ligament (OPLL) is a kind of disease with physical barriers and neurological disorders. The objective of this study was to explore the differentially expressed genes (DEGs) in OPLL patient ligament cells and identify the target sites for the prevention and treatment of OPLL in clinic. Gene expression data GSE5464 was downloaded from Gene Expression Omnibus; then DEGs were screened by limma package in R language, and changed functions and pathways of OPLL cells compared to normal cells were identified by DAVID (The Database for Annotation, Visualization and Integrated Discovery); finally, an interaction network of DEGs was constructed by string. A total of 1536 DEGs were screened, with 31 down-regulated and 1505 up-regulated genes. Response to wounding function and Toll-like receptor signaling pathway may involve in the development of OPLL. Genes, such as PDGFB, PRDX2 may involve in OPLL through response to wounding function. Toll-like receptor signaling pathway enriched genes such as TLR1, TLR5, and TLR7 may involve in spine cord injury in OPLL. PIK3R1 was the hub gene in the network of DEGs with the highest degree; INSR was one of the most closely related genes of it. OPLL related genes screened by microarray gene expression profiling and bioinformatics analysis may be helpful for elucidating the mechanism of OPLL.