Studies on causative gene defects in primary neutrophil abnormalities with a purpose of applying it to the gene therapy

本研究对中性粒细胞功能的诱导及其信号转导进行分析，并确定原发性中性粒细胞异常的致病基因缺陷，以期将其应用于基因治疗。中性粒细胞功能的诱导及其信号转导分析(1)中性粒细胞功能是由黏附分子CD11b诱导的，CD11b通过中性粒细胞与内皮细胞之间的相互作用调节中性粒细胞功能。(2)酪氨酸激酶被证明是FMLP诱导趋化的特异性信号通路。原发性中性粒细胞异常的致病基因缺陷分析(1)先天性中性粒细胞减少症(Kostmann型)：通过培养两名患者的骨髓细胞，有可能获得足够的中性粒细胞用于目前的研究。G-CSF受体数量未见减少，其mRNA表达正常。(2)先天性中性粒细胞特异性颗粒缺乏症：不仅防御素、乳铁蛋白、胶原酶的mRNA无表达或表达降低。用几种限制性内切酶对这些基因组DNA进行Southern杂交分析，未能显示出异常条带。分析基因侧翼区域和启动子的研究目前正在进行中。

The present studies were conducted to analyze the induction of neutrophil functions and its signal transduction and to determine the causative gene defects in primary neutrophil abnormalities with a purpose of applying it to the gene therapy.1. Analysis of induction of neutrophil functions and its signal transduction(1) Neutrophil functions were induced via CD11b, an adhesion molecule, which plays a role in regulating the functions by the interaction between neutrophils and endothelial cells.(2) The tyrosine kinase was demonstrated to be a specific signaling pathway for FMLP-induced chemotaxis.2. Analysis of causative gene defects in primary neutrophil abnormalities(1) Congenital neutropenia (kostmann type) : It was possible to get neutrophils enough to use for the present studies by culturing the bone marrow cells in two patients. The G-CSF receptor was not decreased in the number, and its mRNA expression was normal.(2) Congenital neutrophil-specific granule deficiency : There was no or reduced expression of mRNA for not only defensins but also lactoferrin and collagenase. Southern blot analysis of these genomic DNAs failed to demonstrate abnormal band by use of several restriction enzymes. Studies are now in progress to analyze the flanking regions and promoter of the genes.