Abstract

Bone loss is caused by inflammation and is mediated by pro-inflammatory cytokines that control bone formation and bone resorption. The study aimed to determine the effect of secreted factors from human bone marrow-derived stromal cells (hBMSC) of no-heterotopic bone-forming capacity (hBMSC^–Bone) cells on the differentiation potential of hBMSC which capable of creating bone in-vivo (hBMSC^+Bone) and dissect the molecular signature of these cells for understanding the complicated relationship of stem cells and microenvironment. hBMSC cultures are heterogenous with respect to differentiation and function. However, the nature of interaction between different cell populations within hBMSC cultures is poorly investigated. We employed two clonal hBMSC lines which exhibit different functional phenotypes based on the presence of either high or low osteoblastic differentiation capacity, bone forming (hBMSC^+Bone) and non-bone forming (hBMSC^−Bone), and examined their biological interaction. Adding conditioned media (CM) of hBMSC^−Bone cultures resulted in suppression of cell proliferation and osteoblasts differentiation of hBMSC^+Bone. Microarray analysis of CM-treated hBMSC^+Bone revealed significant enrichment of several pathways, including TGFβ signaling. Follow-up experiments corroborated the inhibitory effects on TGFβ signaling as evidenced by decreased SMAD2 phosphorylation and TGFβ-responsive genes (TAGLN, ACTA2 and TPM1). Interestingly, IL1β is highly expressed in hBMSC^−Bone and is present in its CM. Incubating hBMSC^−Bone with rhIL-1RI rescued the functional phenotype of hBMSC^−Bone with respect to cell proliferation and differentiation into osteoblasts, and upregulated TGFβ-responsive genes. These data demonstrated that IL1β-TGFβ signaling is part of the intercellular communication within the heterogenous population of hBMSCs and regulates their commitment to osteoblastic fate.

Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1939784 .

摘要

骨质流失是由炎症引起的，由控制骨形成和骨吸收的促炎细胞因子介导。该研究的目的是确定从人骨髓衍生的基质无异位骨形成的能力（的hBMSC的细胞（的hBMSC）分泌的因子的影响^-Bone）上的hBMSC的分化潜能细胞，其能够产生骨的活体内（ hBMSC ^+骨) 并剖析这些细胞的分子特征，以了解干细胞与微环境的复杂关系。hBMSC 培养物在分化和功能方面是异质的。然而，对 hBMSC 培养物中不同细胞群之间相互作用的性质研究甚少。我们采用了两种克隆 hBMSC 系，它们根据高或低成骨细胞分化能力、骨形成 (hBMSC ^{+ Bone} ) 和非骨形成 (hBMSC ^-Bone )的存在表现出不同的功能表型，并检查了它们的生物相互作用。添加 hBMSC ^-Bone培养物的条件培养基 (CM) 会抑制 hBMSC ^{+ Bone}的细胞增殖和成骨细胞分化. CM 处理的 hBMSC ^{+ Bone 的}微阵列分析揭示了几种途径的显着富集，包括 TGFβ 信号传导。后续实验证实了对 TGFβ 信号传导的抑制作用，如 SMAD2 磷酸化和 TGFβ 反应基因（TAGLN、ACTA2和TPM1）降低所证明的那样。有趣的是，IL1β 在 hBMSC ^{-Bone 中}高度表达并存在于其 CM 中。hBMSC - ^Bone与 rhIL-1RI 一起孵育挽救了 hBMSC- ^Bone的功能表型关于细胞增殖和分化为成骨细胞，并上调 TGFβ 反应基因。这些数据表明 IL1β-TGFβ 信号传导是 hBMSCs 异质群体内细胞间通讯的一部分，并调节它们对成骨细胞命运的承诺。

本文的补充数据可在 https://doi.org/10.1080/13102818.2021.1939784 在线获得。