■软骨干/祖细胞(CSPC)在维持软骨稳态中起关键作用。然而,CSPC表型波动对软骨退变的影响以及CSPC在OA发病机制中的作用尚不清楚。
■收集3名非OA和10名OA患者的软骨样品。分离来自这些患者的人CSPC(hCSPC),已识别,并评估细胞功能。此外,分离来自OA患者的软骨细胞。体外研究了Yes相关蛋白(YAP)表达对hCSPC的影响。采用Hulth's法建立OA大鼠模型。关节内注射慢病毒介导的YAP(Lv-YAP)或慢病毒介导的YAPRNAi(Lv-YAP-RNAi)以调节大鼠关节中的YAP表达。此外,通过关节内注射移植过表达或沉默YAP的同种异体大鼠CSPC(rCSPC)。我们还评估了大鼠模型中rCSPC的功能和OA相关的软骨表型。最后,检测过表达YAP的OArCSPC的转录组,以探索YAP在rCSPC中的潜在下游靶标。
■来自OA患者的hCSPC表现出不同的软骨形成能力。其中,hCSPC的一个子集显示出明显的功能障碍,包括软骨分化受损,抑制增殖和迁移,和润滑素的下调。此外,YAP在静态非OAhCSPC中低表达,在激活的OAhCSPC中上调,但在功能失调的OAhCSPC中显著下调。值得注意的是,YAP在OAhCSPC中的过表达促进了细胞增殖,润滑素生产,细胞迁移,和衰老,而沉默YAP则有相反的效果。在体内,关节中YAP的上调延迟了OA的进展,并改善了rCSPC的软骨再生能力。使用转录组学分析,我们发现YAP可能通过上调杆状病毒IAP重复序列2(BIRC2)调节rCSPC功能.重要的是,BIRC2的敲除部分阻断了YAP对CSPC功能的调节。
■在OA中,CSPC的功能障碍损害了软骨的内在修复能力并损害了软骨的稳态。值得注意的是,转录共激活因子YAP通过潜在的靶基因BIRC2在维持CSPC功能中起关键作用。
■在这项研究中,我们观察到靶向YAP-BIRC2轴改善了OA的CSPC功能并恢复了软骨稳态。这项研究提供了一种潜在的干细胞修饰OA疗法。
UNASSIGNED: The cartilage stem/progenitor cells (CSPC) play a critical role in maintaining cartilage homeostasis. However, the effects of phenotypic fluctuations of CSPC on cartilage degeneration and the role of CSPC in the pathogenesis of OA is largely unknown.
UNASSIGNED: The cartilage samples of 3 non-OA and 10 OA patients were collected. Human CSPC (hCSPC) derived from these patients were isolated, identified, and evaluated for cellular functions. Additionally, chondrocytes derived from OA patients were isolated. The effect of Yes-associated protein (YAP) expression on hCSPC was investigated in vitro. The OA rat model was established by Hulth\'s method. Lentivirus-mediated YAP (Lv-YAP) or lentivirus-mediated YAP RNAi (Lv-YAP-RNAi) was injected intra-articularly to modulate YAP expression in rat joints. In addition, allogeneic rat CSPC (rCSPC) overexpressing or silencing YAP were transplanted by intra-articularly injection. We also evaluated the functions of rCSPC and the OA-related cartilage phenotype in the rat model. Finally, the transcriptome of OA rCSPC overexpressing YAP was examined to explore the potential downstream targets of YAP in rCSPC.
UNASSIGNED: hCSPC derived from OA patients exhibited differential chondrogenesis capacity. Among them, a subset of hCSPC showed pronounced dysfunction, including impaired chondrogenic differentiation, inhibition of proliferation and migration, and downregulation of lubricin. Additionally, YAP was lowly expressed in quiescent non-OA hCSPC, upregulated in activated OA hCSPC, but significantly downregulated in dysfunctional OA hCSPC. Notably, the overexpression of YAP in OA hCSPC improved the proliferation, lubricin production, cell migration, and senescence, while silencing YAP had the opposite effect. In vivo, upregulation of YAP in the joint delayed OA progression and improved the cartilage regeneration capacity of rCSPC. Using transcriptomic analysis, we found that YAP may regulate rCSPC function by upregulating Baculoviral IAP repeat-containing 2 (BIRC2). Importantly, the knockdown of BIRC2 partly blocked the regulation of YAP on the CSPC function.
UNASSIGNED: Dysfunction of CSPC compromises the intrinsic repair capacity of cartilage and impairs cartilage homeostasis in OA. Notably, the transcriptional co-activator YAP plays a critical role in maintaining CSPC function through potential target gene BIRC2.
UNASSIGNED: In this study, we observed targeting the YAP-BIRC2 axis improved the CSPC function and restored the cartilage homeostasis in OA. This study provides a potential stem cell-modifying OA therapy.