Macroautophagy has been implicated in modulating the therapeutic function of mesenchymal stromal cells (MSCs). However, the biological function of chaperone-mediated autophagy (CMA) in MSCs remains elusive. Here, we found that CMA was inhibited in MSCs in response to the proinflammatory cytokines interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). In addition, suppression of CMA by knocking down the CMA-related lysosomal receptor lysosomal-associated membrane protein 2 (LAMP-2A) in MSCs significantly enhanced the immunosuppressive effect of MSCs on T cell proliferation, and as expected, LAMP-2A overexpression in MSCs exerted the opposite effect on T cell proliferation. This effect of CMA on the immunosuppressive function of MSCs was attributed to its negative regulation of the expression of chemokine C-X-C motif ligand 10 (CXCL10), which recruits inflammatory cells, especially T cells, to MSCs, and inducible nitric oxide synthase (iNOS), which leads to the subsequent inhibition of T cell proliferation via nitric oxide (NO). Mechanistically, CMA inhibition dramatically promoted IFN-γ plus TNF-α-induced activation of NF-κB and STAT1, leading to the enhanced expression of CXCL10 and iNOS in MSCs. Furthermore, we found that IFN-γ plus TNF-α-induced AKT activation contributed to CMA inhibition in MSCs. More interestingly, CMA-deficient MSCs exhibited improved therapeutic efficacy in inflammatory liver injury. Taken together, our findings established CMA inhibition as a critical contributor to the immunosuppressive function of MSCs induced by inflammatory cytokines and highlighted a previously unknown function of CMA.

巨自噬与调节间充质基质细胞（MSC）的治疗功能有关。然而，间充质干细胞中伴侣介导的自噬（CMA）的生物学功能仍然难以捉摸。在这里，我们发现 MSC 中的 CMA 在促炎细胞因子干扰素-γ (IFN-γ) 和肿瘤坏死因子-α (TNF-α) 的作用下受到抑制。此外，通过敲低MSC中的CMA相关溶酶体受体溶酶体相关膜蛋白2（LAMP-2A）来抑制CMA，可显着增强MSC对T细胞增殖的免疫抑制作用，并且正如预期的那样，MSC中LAMP-2A过度表达对 T 细胞增殖产生相反的作用。 CMA 对 MSC 免疫抑制功能的这种作用归因于其对趋化因子 CXC 基序配体 10 (CXCL10) 和诱导型一氧化氮合酶 (iNOS) 表达的负调节，CXC 基序配体 10 将炎症细胞，尤其是 T 细胞募集到 MSC 中。随后通过一氧化氮 (NO) 抑制 T 细胞增殖。从机制上讲，CMA 抑制显着促进 IFN-γ 和 TNF-α 诱导的 NF-κB 和 STAT1 激活，导致 MSC 中 CXCL10 和 iNOS 的表达增强。此外，我们发现 IFN-γ 加上 TNF-α 诱导的 AKT 激活有助于抑制 MSC 中的 CMA。更有趣的是，CMA 缺陷的 MSC 在炎症性肝损伤中表现出改善的治疗效果。综上所述，我们的研究结果表明 CMA 抑制是炎症细胞因子诱导的 MSC 免疫抑制功能的关键因素，并强调了 CMA 以前未知的功能。