Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31324, United States.
Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, United States.
Stem Cells. 2024 Aug 1;42(8):736-751. doi: 10.1093/stmcls/sxae040.
Mesenchymal stromal cells (MSCs) are investigated as cellular therapeutics for inflammatory bowel diseases and associated perianal fistula, although consistent efficacy remains a concern. Determining host factors that modulate MSCs' potency including their secretion of angiogenic and wound-healing factors, immunosuppression, and anti-inflammatory properties are important determinants of their functionality. We investigated the mechanisms that regulate the secretion of angiogenic and wound-healing factors and immune suppression of human bone marrow MSCs. Secretory analysis of MSCs focusing on 18 angiogenic and wound-healing secretory molecules identified the most abundancy of vascular endothelial growth factor A (VEGF-A). MSC viability and secretion of other angiogenic factors are not dependent on VEGF-A secretion which exclude the autocrine role of VEGF-A on MSC's fitness. However, the combination of inflammatory cytokines IFNγ and TNFα reduces MSC's VEGF-A secretion. To identify the effect of intestinal microvasculature on MSCs' potency, coculture analysis was performed between human large intestine microvascular endothelial cells (HLMVECs) and human bone marrow-derived MSCs. HLMVECs do not attenuate MSCs' viability despite blocking their VEGF-A secretion. In addition, HLMVECs neither attenuate MSC's IFNγ mediated upregulation of immunosuppressive enzyme indoleamine 2,3-dioxygenase nor abrogate suppression of T-cell proliferation despite the attenuation of VEGF-A secretion. We found that HLMVECs express copious amounts of endothelial nitric oxide synthase and mechanistic analysis showed that pharmacological blocking reverses HLMVEC-mediated attenuation of MSC's VEGF-A secretion. Together these results suggest that secretion of VEGF-A and immunosuppression are separable functions of MSCs which are regulated by distinct mechanisms in the host.
间充质基质细胞 (MSCs) 被研究作为治疗炎症性肠病和相关肛周瘘的细胞疗法，尽管一致性疗效仍然是一个关注点。确定调节 MSCs 效力的宿主因素，包括它们分泌的血管生成和伤口愈合因子、免疫抑制和抗炎特性，是其功能的重要决定因素。我们研究了调节人骨髓间充质基质细胞分泌血管生成和伤口愈合因子以及免疫抑制的机制。对间充质基质细胞分泌的 18 种血管生成和伤口愈合分泌分子进行的分泌分析确定了血管内皮生长因子 A (VEGF-A) 的丰度最高。MSC 的活力和其他血管生成因子的分泌不依赖于 VEGF-A 的分泌，这排除了 VEGF-A 对 MSC 适应性的自分泌作用。然而，炎性细胞因子 IFNγ 和 TNFα 的组合减少了 MSC 的 VEGF-A 分泌。为了确定肠道微血管对 MSCs 效力的影响，进行了人大肠微血管内皮细胞 (HLMVECs) 和人骨髓来源的 MSCs 之间的共培养分析。尽管阻断了 VEGF-A 的分泌，但 HLMVECs 并没有减弱 MSCs 的活力。此外，尽管阻断了 VEGF-A 的分泌，但 HLMVECs 既没有减弱 MSC 对 IFNγ 介导的免疫抑制酶吲哚胺 2,3-双加氧酶的上调作用，也没有消除对 T 细胞增殖的抑制作用。我们发现 HLMVECs 表达大量内皮型一氧化氮合酶，机制分析表明，药理学阻断可逆转 HLMVEC 介导的 MSC 的 VEGF-A 分泌减弱。这些结果表明，VEGF-A 的分泌和免疫抑制是 MSCs 的可分离功能，这些功能受到宿主中不同机制的调节。
