Liang Meng, Guo Xuemin, Wu Heming, Zhong Zhixiong
The First Clinical Medical College, Gannan Medical University, Ganzhou, China.
Center for Cardiovascular Diseases, Meizhou People's Hospital (Huangtang Hospital), Meizhou Academy of Medical Sciences, Meizhou, China.
J Thorac Dis. 2022 Jan;14(1):147-157. doi: 10.21037/jtd-21-1901.
To explore the potential mechanism of inducible co-stimulator (ICOS) inhibition of lipid phagocytosis in human aortic smooth muscle cells (HASMCs).
Excess Dil (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate)-labeled oxidized low-density lipoprotein (ox-LDL) was used to induce HASMCs to form a foam cell model; HASMCs were cultured together with ICOS-overexpressed JurKat (JK-ICOS) cells or recombinant human ICOS protein (rICOS protein) to be stimulated, and a confocal laser microscope was used to observe the lipid phagocytosis of HASMCs. Reverse transcription quantitative polymerase chain reaction (RT-qPCR), western blot, and immunofluorescence staining were used to detect the expression of the lipid phagocytic receptor, cluster of differentiation 36 (CD36) in HASMCs.
The uptake of Dil ox-LDL by HASMCs was concentration-dependent, and excessive Dil ox-LDL uptake led to lipid accumulation in HASMCs. Pretreatment with JK-ICOS cells or rICOS protein for HASMCs 48 hours reduced Dil ox-LDL-induced lipid accumulation. Compared with HASMCs co-cultured with empty lentiviral JurKat (JK-EV) cells, the messenger RNA (mRNA) and protein expressions of CD36 in HASMCs co-cultured with JK-ICOS cells were significantly down-regulated. The results of immunofluorescence staining showed that co-culturing with JK-ICOS cells could down-regulate ox-LDL-induced expression of CD36 in HASMCs, but JK-EV cells could not. Similarly, the results of qPCR, western blot, and immunofluorescence staining showed that rICOS protein could down-regulate the ox-LDL-induced expression of CD36 in HASMCs, but this down-regulation was not as significant as that in JK-ICOS cells.
ICOS could inhibit the lipid phagocytosis of HASMCs by down-regulating the expression of CD36, suggesting a potential anti-atherosclerosis (anti-AS) mechanism of ICOS, and preventing ox-LDL-induced formation of myogenic foam cells.
探讨诱导性共刺激分子（ICOS）抑制人主动脉平滑肌细胞（HASMCs）脂质吞噬作用的潜在机制。
用过量的DiI（1,1'-二油酰基-3,3,3',3'-四甲基吲哚碳菁高氯酸盐）标记的氧化低密度脂蛋白（ox-LDL）诱导HASMCs形成泡沫细胞模型；将HASMCs与过表达ICOS的JurKat细胞（JK-ICOS）或重组人ICOS蛋白（rICOS蛋白）共同培养以进行刺激，并用共聚焦激光显微镜观察HASMCs的脂质吞噬情况。采用逆转录定量聚合酶链反应（RT-qPCR）、蛋白质免疫印迹法和免疫荧光染色检测HASMCs中脂质吞噬受体分化簇36（CD36）的表达。
HASMCs对DiI ox-LDL的摄取呈浓度依赖性，过量摄取DiI ox-LDL导致HASMCs内脂质蓄积。用JK-ICOS细胞或rICOS蛋白预处理HASMCs 48小时可减少DiI ox-LDL诱导的脂质蓄积。与空载体慢病毒JurKat细胞（JK-EV）共培养的HASMCs相比，与JK-ICOS细胞共培养的HASMCs中CD36的信使核糖核酸（mRNA）和蛋白表达明显下调。免疫荧光染色结果显示，与JK-ICOS细胞共培养可下调ox-LDL诱导的HASMCs中CD36的表达，而与JK-EV细胞共培养则无此作用。同样，qPCR、蛋白质免疫印迹法和免疫荧光染色结果显示，rICOS蛋白可下调ox-LDL诱导的HASMCs中CD36的表达，但这种下调作用不如JK-ICOS细胞显著。
ICOS可通过下调CD36的表达抑制HASMCs的脂质吞噬，提示ICOS具有潜在的抗动脉粥样硬化（抗AS）机制，并可防止ox-LDL诱导的肌源性泡沫细胞形成。
