Physiology and Pathophysiology of Selectins,Integrins, and IgSf Cell Adhesion Molecules Focusing on Inflammation. A Paradigm Model on Infectious Endocarditis

Abstract

The development of adhesion bonds, either among cells or among cells and components of the extracellular matrix, is a crucial process. These interactions are mediated by some molecules collectively known as adhesion molecules (CAMs). CAMs are ubiquitously expressed proteins playing a central role in controlling cell migration, proliferation, survival, and apoptosis. Besides their key function in physiological maintenance of tissue integrity, CAMs play an eminent role in various pathological processes such as cardiovascular disorders, atherogenesis, atherosclerotic plaque progression and regulation of the inflammatory response. CAMs such as selectins, integrins, and immunoglobulin superfamily take part in interactions between leukocyte and vascular endothelium (leukocyte rolling, arrest, firm adhesion, migration). Experimental data and pathologic observations support the assumption that pathogenic microorganisms attach to vascular endothelial cells or sites of vascular injury initiating intravascular infections. In this review a paradigm focusing on cell adhesion molecules pathophysiology and infective endocarditis development is given.     

CD34+和CD34-细胞在NOD/SCID小鼠体内的造血重建

利用非肥胖糖尿病型重症联合免疫缺陷型(NOD/SCID)小鼠模型, 比较了新鲜及培养后的CD34+和CD34-细胞在体内植入及重建造血能力。从新鲜脐血及培养后的单个核细胞(MNC)中分离出CD34+和CD34-细胞, 经尾静脉输注入经亚致死剂量照射的NOD/SCID小鼠体内, 6周后处死存活的小鼠, 取其骨髓、脾脏和外周血细胞, 分别进行细胞表型分析、造血集落形成单位和人特异性基因的检测。经检测, 输注CD34+细胞和混合细胞的小鼠, 其体内CD45+细胞及人源各系血细胞的含量相近, 两者均远远高于输注CD34-细胞的小鼠。输注培养后CD34-细胞的小鼠饲养6周后全部死亡,输注培养后CD34+细胞的小鼠存活率约为66.7%, 而输注培养后混合细胞的小鼠全部存活, 且在两组存活的小鼠体内均能检测到CD45+细胞及人源各系血细胞。结果表明: 无论是新鲜还是培养后的CD34+细胞均具有在NOD/SCID小鼠体内植入和重建造血能力, 而CD34-细胞不具有该能力, 但CD34-细胞与CD34+细胞同时输注有助于提高小鼠的存活率, 说明其对CD34+细胞在小鼠体内发挥植入和造血重建能力有一定的辅助作用。     

The Tetraspanin CD9 Influences the Adhesion, Spreading, and Pericellular Fibronectin Matrix Assembly of Chinese Hamster Ovary Cells on Human Plasma Fibronectin

The role of CD9 in cell adhesion and spreading on adhesive proteins was investigated using a transfected Chinese hamster ovary (CHO) cell system. CD9 cell surface expression resulted in reduced adhesion and increased spreading on fibronectin (Fn). Whereas mock-transfected (mock CHO) and na?ve CHO cells assumed a typical fibroblast spindle shape morphology, CD9-transfected (CD9-CHO) cells were polygonal with many filipodial projections and exhibited a twofold greater surface area. The spread morphology of CD9-CHO cells, but not mock CHO cells, was inhibited by PB1 mAb blockade of alpha(5)beta(1), suggesting that the coexpression of alpha(5)beta(1) and CD9 influenced cell activity on Fn. The second extracellular loop of CD9 was implicated in regulation of adhesion since reduced CD9-CHO cell adhesion on Fn was reversed by either anti-CD9 antibody ligation to the second extracellular loop or with cells expressing a CD9 mutant lacking the second extracellular loop domain. Using cell adhesion assays and ELISA, we demonstrated CD9 binding to the HEP2/IIICS region of Fn. Finally, CD9 expression resulted in a twofold reduction in Fn-rich pericellular matrix assembly. Our observations show that CD9 dramatically influences CHO cell interactions with Fn and suggest that CD9 has an important role in modulating cell-extracellular matrix interactions.