Department of Surgery, Medicine Dentistry and Morphological Sciences With Interest in Transplant, University of Modena and Reggio Emilia, Modena, Italy.
Department of Engineering Sciences and Methods, University of Modena and Reggio Emilia, Modena, Italy.
Stem Cell Res Ther. 2023 Feb 18;14(1):31. doi: 10.1186/s13287-023-03254-2.
Human dental pulp stem cells represent a mesenchymal stem cell niche localized in the perivascular area of dental pulp and are characterized by low immunogenicity and immunomodulatory/anti-inflammatory properties. Pericytes, mural cells surrounding the endothelium of small vessels, regulate numerous functions including vessel growth, stabilization and permeability. It is well established that pericytes have a tight cross talk with endothelial cells in neoangiogenesis and vessel stabilization, which are regulated by different factors, i.e., microenvironment and flow-dependent shear stress. The aim of this study was to evaluate the effects of a pulsatile unidirectional flow in the presence or not of an inflammatory microenvironment on the biological properties of pericyte-like cells isolated from human dental pulp (hDPSCs).
Human DPSCs were cultured under both static and dynamic conditions with or without pre-activated peripheral blood mononuclear cells (PBMCs). Pulsatile unidirectional flow shear stress was generated by using a specific peristaltic pump. The angiogenic potential and inflammatory properties of hDPSCs were evaluated through reverse phase protein microarrays (RPPA), confocal immunofluorescence and western blot analyses.
Our data showed that hDPSCs expressed the typical endothelial markers, which were up-regulated after endothelial induction, and were able to form tube-like structures. RPPA analyses revealed that these properties were modulated when a pulsatile unidirectional flow shear stress was applied to hDPSCs. Stem cells also revealed a downregulation of the immune-modulatory molecule PD-L1, in parallel with an up-regulation of the pro-inflammatory molecule NF-kB. Immune-modulatory properties of hDPSCs were also reduced after culture under flow-dependent shear stress and exposure to an inflammatory microenvironment. This evidence was strengthened by the detection of up-regulated levels of expression of pro-inflammatory cytokines in PBMCs.
In conclusion, the application of a pulsatile unidirectional flow shear stress induced a modulation of immunomodulatory/inflammatory properties of dental pulp pericyte-like cells.
人牙髓干细胞代表着一种间充质干细胞龛，定位于牙髓的血管周围区域，其特点是免疫原性低，具有免疫调节/抗炎特性。周细胞是围绕小血管内皮的壁细胞，可调节多种功能，包括血管生长、稳定和通透性。众所周知，周细胞在新血管生成和血管稳定中有紧密的相互作用，这是由不同的因素调节的，即微环境和依赖于流动的剪切力。本研究旨在评估在存在或不存在炎症微环境的情况下，单向脉动流对人牙髓（hDPSCs）来源的周细胞样细胞的生物学特性的影响。
在静态和动态条件下，分别培养 hDPSCs，同时或不预先激活外周血单核细胞（PBMCs）。使用特定的蠕动泵产生单向脉动流剪切力。通过反转录蛋白微阵列（RPPA）、共聚焦免疫荧光和 Western blot 分析评估 hDPSCs 的血管生成潜能和炎症特性。
我们的数据表明，hDPSCs 表达典型的内皮标志物，这些标志物在诱导内皮后上调，并能够形成管状结构。RPPA 分析表明，当向 hDPSCs 施加单向脉动流剪切力时，这些特性会发生调节。干细胞还表现出免疫调节分子 PD-L1 的下调，同时促炎分子 NF-kB 的上调。在依赖于流动的剪切力下培养和暴露于炎症微环境后，hDPSCs 的免疫调节特性也降低。这一证据得到了 PBMCs 中促炎细胞因子表达水平上调的检测结果的加强。
总之，单向脉动流剪切力的应用诱导了牙髓周细胞样细胞的免疫调节/炎症特性的调节。
