Bernaerts Eline, Ahmadzadeh Kourosh, De Visscher Amber, Malengier-Devlies Bert, Häuβler Daniel, Mitera Tania, Martens Erik, Krüger Achim, De Somer Lien, Matthys Patrick, Vandooren Jennifer
Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven, 3000 Leuven, Belgium.
Centre for Reproductive Health and Centre for Inflammation Research, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh EH16 4UU, UK.
iScience. 2024 Oct 16;27(11):111171. doi: 10.1016/j.isci.2024.111171. eCollection 2024 Nov 15.
Proteases are key effectors in macrophage function during the initiation and resolution of inflammation. Recent studies have shown that some proteases, traditionally considered extracellular, also exhibit enzymatic and non-enzymatic functions within the cell. This study explores the differential protease landscapes of macrophages based on their phenotype. Human monocytes were isolated from healthy volunteers and stimulated with M-CSF (resting macrophages), LPS/IFN-γ (inflammatory macrophages), or IL-4 (immunosuppressive macrophages). IL-4-stimulated macrophages secreted higher levels of MMPs and natural protease inhibitors compared to LPS/IFN-γ-stimulated macrophages. Increased extracellular proteolytic activity was detected in LPS/IFN-γ-stimulated macrophages while IL-4 stimulation increased cell-associated proteolytic activity, particularly for MMPs. Subcellular fractionation and confocal microscopy revealed the uptake of extracellular MMP-9 and its relocation to the nucleus in IL-4-stimulated, though not in LPS/IFN-γ-stimulated macrophages. Collectively, macrophages alter the subcellular location and activity of their MMPs based on the stimuli received, suggesting another mechanism for protease regulation in macrophage biology.
蛋白酶是炎症起始和消退过程中巨噬细胞功能的关键效应分子。最近的研究表明，一些传统上被认为是细胞外的蛋白酶，在细胞内也表现出酶促和非酶促功能。本研究基于巨噬细胞的表型探索其不同的蛋白酶谱。从健康志愿者中分离出人类单核细胞，并用M-CSF（静息巨噬细胞）、LPS/IFN-γ（炎性巨噬细胞）或IL-4（免疫抑制巨噬细胞）进行刺激。与LPS/IFN-γ刺激的巨噬细胞相比，IL-4刺激的巨噬细胞分泌更高水平的基质金属蛋白酶（MMPs）和天然蛋白酶抑制剂。在LPS/IFN-γ刺激的巨噬细胞中检测到细胞外蛋白水解活性增加，而IL-4刺激则增加了细胞相关的蛋白水解活性，尤其是对于MMPs。亚细胞分级分离和共聚焦显微镜显示，在IL-4刺激的巨噬细胞中，细胞外MMP-9被摄取并重新定位到细胞核，但在LPS/IFN-γ刺激的巨噬细胞中则没有。总体而言，巨噬细胞根据所接收的刺激改变其MMPs的亚细胞定位和活性，这表明巨噬细胞生物学中蛋白酶调节的另一种机制。
