Abnormal destruction of the components of the articular extracellular matrix (ECM) such as type II collagen and aggrecan caused by advanced glycation end products (AGEs) has been considered as one of the pathological characteristics of osteoarthritis (OA). Receptor-interacting protein 1 (RIP1), an important serine/threonine kinase, possesses a variety of biological functions including cell proliferation, survival and death. The physiological roles of RIP1 in OA have not been reported before. Here, we found that AGEs increased the expression of RIP1 in human chondrosarcoma cell line SW1353 cells. Importantly, we found that antagonism of RIP1 using its specific inhibitor necrostatin-1 (Nec-1) ameliorated AGE-induced degradation of type II collagen and aggrecan in SW1353 cells. We also found that treatment with Nec-1 reduced the expression of MMP-3 and MMP-13 but restored the expression of Tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. Also, our results indicate that Nec-1 inhibited AGE-induced expression of ADAMTS-4 and ADAMTS-5. Mechanistically, we found that Nec-1 treatment inhibited the activation of JNK and the transcriptional factor AP-1 by reducing the expressions of c-Fos and c-Jun, the two main components of AP-1. Additionally, we found that Nec-1 treatment abolished AGE-induced activation of the transcriptional factor NF-jB by suppressing the nuclear translocation of p65. These findings suggest that RIP1 might be an important therapeutic target of OA.

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The objective of the present study was to determine the role of RP11-84C13.1 in osteoporosis (OP) and its molecular mechanism. First, clinical samples were collected from OP patients and normal control patients. Human bone marrow stromal cells (hBMSCs) were extracted from femoral head tissues. Runt-related transcription factor 2 (RUNX2) and RP11-84C13.1 serum levels were assessed by reverse transcription-quantitative (RT-q)PCR. Following transfection of pcDNA-RP11-84C13.1, si-RP11-84C13.1, microRNA (miRNA)-23b-3p mimic and miRNA-23b-3p inhibitor, the expression levels of RUNX2 and RP11-84C13.1 were determined by RT-qPCR. In addition, the osteogenic ability of hBMSCs was assessed by Alizarin Red staining. The binding of RP11-84C13.1 to miRNA-23b-3p and the binding of miRNA-23b-3p to RUNX2 was confirmed by dual-luciferase reporter gene assay. Long non-coding RNA (lncRNA) RP11-84C13.1 was significantly downregulated in the serum of OP patients. The osteogenic differentiation-related genes RUNX2 and RP11-84C13.1 were markedly upregulated in a time-dependent manner, while the miRNA-23b-3p level gradually decreased in hBMSCs with the prolongation of osteogenesis. RP11-84C13.1 knockdown inhibited the osteogenic differentiation of hBMSCs. Furthermore, RP11-84C13.1 regulated RUNX2 expression by targeting miRNA-23b-3p. Overexpression of miRNA-23b-3p partially reversed the promoting effect of RP11-84C13.1 on the osteogenesis of hBMSCs. In conclusion, lncRNA RP11-84C13.1 upregulated RUNX2 by absorbing miRNA-23b-3p, and thus induced hBMSC osteogenesis to alleviate osteoporosis.

Wushen (WS) is a mixed food containing 55 natural products that is beneficial to human health. This study aimed to reveal the preventive effect of WS on aging via a combined analysis of gut microbiome and metabolome. Senescence-accelerated mouse prone 8 (SAMP8) mice were used as aging model and senescence-accelerated mouse resistant 1 (SAMR1) mice as control. The mice were fed four diet types; control diet (for SAMR1 mice), standard diet (for SAMP8 mice, as SD group), WS diet, and fecal microbiota transplantation (FMT; transplanted from aging-WS mice). Our results showed that the weight, food intake, neurological function, and general physical conditions significantly improved in WS-fed mice compared to those fed with SD. The CA1 hippocampal region in WS-fed aged mice showed fewer shriveled neurons and increased neuronal layers compared to that of the SD group. WS-fed mice showed a decrease in malondialdehyde and an increase in superoxide dismutase levels in the brain; additionally, IL-6 and TNF-α levels significantly decreased, whereas IL-2 levels and the proportion of lymphocytes, CD3+CD8+ T, and CD4+IFNγ+T cells increased in WS-fed mice. After fed with WS, the abundance of Ruminococcus and Butyrivibrio markedly increased, whereas Lachnoclostridium and Ruminiclostridium significantly decreased in the aging mice. In addition, 887 differentially expressed metabolites were identified in fecal samples, among these, Butyrivibrio was positively correlated with D-glucuronic acid and Ruminococcus was positively associated with 5-acetamidovalerate. These findings provide mechanistic insight into the impact of WS on aging, and WS may be a valuable diet for preventing aging.

Osteogenic differentiation (OD) of bone marrow mesenchymal stem cells (BMSCs) is critically important for mitigation of osteoporosis. Glucocorticoids (GCs) are extensively used for treating chronic inflammation, although long‐term exposure to GCs is capable of triggering osteoporosis. microRNAs (miRNAs) have been reported to play a critical role in bone diseases. In the present study, we treated BMSCs with dexamethasone (DEX) during OD to stimulate GC‐mediated osteoporosis. Microarray and quantitative polymerase chain reaction (Q‐PCR) assays demonstrated that miR‐199a was upregulated during OD of BMSCs, while DEX treatment caused a significant reduction in miR‐199a. Alkaline phosphatase (ALP) activity, Alizarin red (AR) staining, and Q‐PCR were applied to assess the role of miRNA‐199a overexpression in DEX‐triggered OD inhibition. miR‐199a was able to rescue OD and ALP activity, which were inhibited by DEX. Additionally, we observed that ALP, BMP2, COL1A1, and Runx2 were increased after transfection of miRNA‐199a mimics. Furthermore, we confirmed that miRNA‐199a facilitates OD of BMSCs through direct inhibition of Klotho protein and messenger RNA expression affecting the downstream fibroblast growth factor receptor 1/extracellular‐signal‐regulated kinase and Janus kinase 1/signal transducer and activator of transcription 1 pathways. This study indicates that miR‐199a plays a critical role in preventing GC‐mediated osteoblast differentiation and may function as a promising miRNA biomarker for osteoporosis.