STRUCTURAL AND FUNCTIONAL STUDIES OF LEDGF

LEDGF的结构和功能研究

• 批准号: 2851740
• 负责人: TOSHIMICHI SHINOHARA
• 金额: $ 31.7万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-12-04 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2851740
• 关键词: aging; animal tissue; autoradiography; cataract; cell membrane; cellular pathology; cytolysis; electron microscopy; enzyme linked immunosorbent assay; epithelium; growth factor; growth factor receptors; histopathology; laboratory mouse; lens; monoclonal antibody; organ culture; pathologic process; protein sequence; protein structure function; surface antigens

The lens is an unusual organ, containing three different cell types. One types does not divide but survives throughout life (central epithelial cells) another consists of dividing cells (epithelial cells in the mitotic zone), & the third is made up of enucleated fiber cells. Survival of central lens epithelial cells (LECs) may require continuous signaling by factors from LECs or other cells. Although most vertebrate cells require growth factors for their growth and proliferation during development, little is known about survival of mature central LECs A novel growth and survival factor was isolated from a human lens epithelial cell cDNA library with auto-antibodies (auto-Abs) cytocidal for LECs and named it lens epithelium-derived growth factor (LEDGF). As a growth factor LEDGF has both autocrine and paracrine effects on LECs, skin fibroblasts, and keratinocytes. It is secreted by the cell, binds to the cell surface, localizes in the nucleus, & regulates protein synthesis. LEDGF is a survival factor for the various cell types against heat- stress, serum starvation-stress, and oxidative-stress, in that the aforementioned cells do not survive without LEDGF. A basic mechanism of cellular survival against these stresses may be an elevated expression of the heat shock proteins (Hsps) 27 and alphaB-crystallin. Abs to LEDGF are prevalent in human sera, and neutralization of LEDGF by auto-Abs blocks cell growth and eventually leads to cell death. We speculate that death of epithelial cells and fibroblasts following the depletion of LEDGF by auto- Abs may be a risk factor for age-related cataract.. This research proposal comprises five aims. 1) To further establish LEDGF as a growth and survival factor for variety of cell types. 2) To determine functionally important sites in LEDGF. 3) To isolate the receptor of LEDGF and determine amino acid sequence. 4) To study expression and regulation of LEDGF and its receptor genes. 5) To investigate the mechanisms of survival of LECs in the presence LEDGF and of death of LECs in its absence. Studying the basic role of LEDGF in survival and death of LECs can enhance our standing of aging including development, growth, and age- related cataract.

镜头是一种不寻常的器官，包含三种不同的细胞类型。一种类型不划分，但生命中的生存（中心上皮细胞）另一种由分裂细胞（有丝分裂区的上皮细胞）组成，第三个由浓核细胞组成。中央晶状体上皮细胞（LEC）的存活可能需要由LEC或其他细胞的因素连续信号传导。尽管大多数脊椎动物细胞在发育过程中都需要生长因子的生长和增殖，但对成熟中央识别的存活鲜为人知，一种新型的生长和存活因子是从具有自动抗体（自动抗体）的人透镜上皮细胞cDNA文库中分离出来的，该蛋白质（自动抗体）的细胞固量是LEC的，并命名为晶状体上皮的生长因子（LEDELIVER-LEDEDERVIRES）。作为生长因子，LedGF对LEC，皮肤成纤维细胞和角质形成细胞具有自分泌和旁分泌作用。它由细胞分泌，结合到细胞表面，定位在细胞核中，并调节蛋白质合成。 LEDGF是针对热应激，血清饥饿压力和氧化压力的各种细胞类型的生存因子，因为没有LEDGF，上述细胞无法生存。针对这些应力的细胞存活的基本机制可能是热休克蛋白（HSP）27和字母晶状体蛋白的表达升高。对LEDGF的ABS在人血清中很普遍，自动ABS对LEDGF进行中和会阻止细胞生长，并最终导致细胞死亡。我们推测，自动abs耗尽后，上皮细胞和成纤维细胞的死亡可能是与年龄相关性白内障的危险因素。该研究建议包括五个目标。 1）进一步建立LEDGF作为各种细胞类型的生长和生存因子。 2）确定LEDGF中功能上重要的站点。 3）分离LEDGF的受体并确定氨基酸序列。 4）研究LEDGF及其受体基因的表达和调节。 5）研究LEC在LEDGF存在和LEC死亡的情况下的生存机制。研究LEDGF在LEC生存和死亡中的基本作用可以增强我们的衰老状况，包括发育，生长和与年龄相关的白内障。