Dual functions of microRNA-17 in maintaining cartilage homeostasis and protection against osteoarthritis.

Damaged hyaline cartilage has no capacity for self-healing, making osteoarthritis (OA) "difficult-to-treat". Cartilage destruction is central to OA patho-etiology and is mediated by matrix degrading enzymes. Here we report decreased expression of miR-17 in osteoarthritic chondrocytes and its deficiency contributes to OA progression. Supplementation of exogenous miR-17 or its endogenous induction by growth differentiation factor 5, effectively prevented OA by simultaneously targeting pathological catabolic factors including matrix metallopeptidase-3/13 (MMP3/13), aggrecanase-2 (ADAMTS5), and nitric oxide synthase-2 (NOS2). Single-cell RNA sequencing of hyaline cartilage revealed two distinct superficial chondrocyte populations (C1/C2). C1 expressed physiological catabolic factors including MMP2, and C2 carries synovial features, together with C3 in the middle zone. MiR-17 is highly expressed in both superficial and middle chondrocytes under physiological conditions, and maintains the physiological catabolic and anabolic balance potentially by restricting HIF-1α signaling. Together, this study identified dual functions of miR-17 in maintaining cartilage homeostasis and prevention of OA.

A thermo-sensitive and injectable hydrogel derived from a decellularized amniotic membrane to prevent intrauterine adhesion by accelerating endometrium regeneration.

Objective To investigate the effect of the injectable hydrogel generated from a decellularized amniotic membrane (dAM)-gel on preventing the development of an intrauterine adhesion (IUA) on a rat model. Methods The dAM-gel was developed from an amniotic membrane (AM) by a process of decellularization, lyophilization, and enzyme digestion. Histological analysis, residual component determination, electronic microscopy and turbidimetric gelation kinetics analysis were performed to characterize the dAM-gel. The proliferation and migration of endometrial cells on the dAM-gel coated surface was examined. IUA was surgically created in rats and received dAM-gel injection immediately after wound creation. Gene profiles of epithelial cells cultured on the dAM-gel coated surface were evaluated by RNA-sequencing. Results The collagen content was retained in the dAM-gel, while the GAG content decreased significantly compared with fresh AM (fAM). Gelation of the gel was temperature-sensitive and showed a matrix concentration-dependent manner. Transplantation of the dAM-gel significantly reduced fibrosis of IUA with a recovered uterine cavity, regenerated endometrium and increased microvascular density, along with elevated pregnancy rate compared with endometrium damage groups. Migration of epithelial cells was greatly promoted by the dAM-gel in a surgically created uterine wound model. By comparing the RNA-sequence data of epithelial cells that were cultured on dAM-gel coated and non-coated surfaces, respectively, distinct gene profiles relative to the cellular migration, adhesion and angiogenesis and involved signaling pathway were identified. Conclusions The injectable dAM-gel developed from AM offers a promising option for preventing endometrial fibrosis by promotion of the re-epithelialization of the damaged endometrium.

Artemisinin derivatives inhibit adipogenic differentiation of 3T3-L1 preadipocytes through upregulation of CHOP.

Artemisinin derivatives could inhibit adipogenic differentiation of 3T3-L1 preadipocytes and prevent obesity in mice. However, the molecular mechanism remains largely unclear. Our research was designed to investigate the specific molecular target of artemisinin derivatives in adipogenic differentiation of 3T3-L1 preadipocytes. Here, we revealed that in response to dihydroartemisinin (DHA) or artesunate (ATS), intracellular lipid was decreased in a concentration dependent manner as shown by BODIPY staining. Quantitative PCR analysis showed that expression of Cebpa, Pparg, Fabp4 and Plin was significantly decreased by DHA treatment in a concentration and time dependent manner. Also, DHA treatment remarkably downregulated expression of CCAAT/enhancer-binding protein α (C/EBPα) and nuclear receptor peroxisome proliferation-activated receptor γ (PPARγ) of adipogenic induced 3T3-L1 cells as assayed by western blotting. RNA-seq analysis identified thousands of differential expression genes (DEGs), among which CHOP expression was significantly improved in DHA treated cells. Upregulation of CHOP was verified by quantitative PCR and western blotting, respectively. Knockdown of CHOP by the specific shRNA revealed that the inhibition of adipogenesis by DHA was strongly blocked, resulting in restored lipid accumulation and expression of adipogenic molecules. In conclusions, the inhibitory effect of DHA on adipogenic differentiation of 3T3-L1 preadipocytes was exerted in a concentration and time dependent manner, which was mediated by expression of CHOP.