Regulation of Cortical Progenitor Mitosis

皮质祖细胞有丝分裂的调节

• 批准号: 10718190
• 负责人: Seonhee Kim
• 金额: $ 45.42万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10718190
• 关键词: Abnormal Cell; Actomyosin; Apical; Binding; Biogenesis; Cannibalism; Cell Death; Cell Nucleus; Cell Survival; Cells; Cellular Structures; Cerebral cortex; Complex; Cre driver; Cytokinesis; DNA Sequence Alteration; Defect; Disease; Event; Gene Expression; Genes; Genetic; Genetic Models; Genomics; Head; Hippocampus; Human; Image; Knowledge; Length; Maintenance; Microcephaly; Mitosis; Mitotic; Molecular; Morphology; Mutation; Myosin ATPase; Neuroepithelial; Neuroglia; Neurons; Pathogenicity; Pathology; Phenotype; Process; Production; Proteins; Radial; Regulation; Side; Signal Transduction; Structure; Substance abuse problem; Surface; TP53 gene; Tertiary Protein Structure; Testing; Time; Ventricular; Virus Diseases; brain size; cell behavior; cell cortex; genome integrity; insight; molecular asymmetry; mouse model; mutant; neoplastic cell; nerve stem cell; novel; prevent; progenitor; protein complex; rho; stem-like cell; tumorigenic

This proposal is to delineate the novel function of apical polarity complex proteins in cortical progenitor mitosis and uncover a new pathogenic mechanism of microcephaly caused by genetic mutation of Pals1 (protein associated with Lin7 1, also known as MPP5). PALS1, which has been incriminated only recently as a gene responsible for microcephaly in humans, encodes a component of the evolutionarily conserved apical polarity complex. Our multiple Pals1 genetic models using different Cre drivers consistently demonstrate overwhelming cortical cell loss because of compromised cell viability. However, the cellular and molecular defects behind the massive cell death found in Pals1 mutants remain unknown. Through extensive time-lapse imaging, we found that Pals1 loss causes abnormally lengthened mitotic progression, consistent with accumulating evidence that anomalies of mitosis are a significant cause of microcephaly. Remarkably, analyses of mitotic cells in static images and time-lapse imaging of Pals1-deficient progenitors revealed the emergence of internalized cells with nuclei inside of mitotic cells. This unusual cellular behavior mimics entosis, which is cell cannibalism utilized by tumor cells to engulf live neighboring cells for pro- or anti-tumorigenic purposes. It is unknown whether this extraordinary cellular event can be pathogenic in other diseases such as microcephaly. Therefore, the mouse model with an entosis-like process in its cortical progenitors will provide important new insights into the pathogenic mechanisms of microcephaly. Our preliminary study demonstrated that cell-in-cell (CIC) structures represent a dynamic and mobile cellular entity that is highly associated with lengthened mitosis and abnormalities in cytokinesis. As in tumor cells, ROCK inhibition completely abrogates CIC structures and restores the normal length of mitosis. Furthermore, we detected a striking increase of the P53 target, P21, in the Pals1 mutants and found that genetic elimination of P53 produces a remarkable rescue of cortical size along with substantial reductions of CIC structures and cell death. These observations lead us to hypothesize that Pals1 loss induces CIC pathology responsible for mitotic defects that compromise genomic content and cortical cell viability through the abnormal activation of Rho-ROCK and p53. To test this, we will determine the biogenesis, maintenance, and elimination of CIC structures and how they impact mitosis and subsequent genomic integrity and fate of cortical cells (Aim1). Next, we will study how Pals1 deletion/reduction causes entosis through abnormal Rho-ROCK activation (Aim2). Finally, we will delineate the effect of P53 activation on CIC formation and Rho-ROCK regulation in Pals1 mutant progenitors (Aim3). The current study provides an important molecular and cellular clue as to how Pals1 mutation causes such a dramatic cortical phenotype as the complete absence of the cerebral cortex and hippocampus. Furthermore, for the first time, our study will establish that an entosis like process can occur in cortical progenitors, providing a novel pathogenic mechanism by which entotic cell cannibalism produces microcephaly.

该建议是描述皮质祖细胞中根尖极性复合物蛋白的新功能 并发现由PALS1的遗传突变引起的新型小头畸形的致病机制（蛋白 与Lin7 1相关，也称为MPP5）。 PALS1，该基因直到最近才被罪名成立 负责人类的小头畸形，编码进化保守的顶极性的组成部分 复杂的。我们使用不同CRE驱动器的多个PALS1遗传模型始终显示出压倒性的 皮质细胞损失由于细胞活力受损。但是，细胞和分子缺陷在 在PALS1突变体中发现的大量细胞死亡仍然未知。通过大量的延时成像，我们发现 PALS1损失导致异常延长有丝分裂进展，这与积累的证据一致 有丝分裂的异常是小头畸形的重要原因。值得注意的是，静态细胞的分析 PALS1缺陷祖细胞的图像和延时成像表明，内部细胞的出现与 有丝分裂细胞内部的核。这种不寻常的细胞行为模仿了诱因 肿瘤细胞吞噬邻近细胞，以促成或抗肿瘤。尚不清楚这是否 非凡的细胞事件在其他疾病（例如小头畸形）中可能是致病性的。因此，鼠标 在其皮质祖细胞中具有诱人过程的模型将为您提供重要的新见解 小头畸形的致病机制。我们的初步研究表明细胞中的细胞（CIC）结构 代表一个动态和移动的细胞实体，与延长有丝分裂和异常相关 在细胞因子中。与肿瘤细胞一样，岩石抑制完全消除了CIC结构并恢复正常 有丝分裂的长度。此外，我们在PALS1突变体和 发现消除p53的遗传消除会产生显着的皮质大小的营救 CIC结构和细胞死亡的减少。这些观察结果使我们假设PALS1损失 诱导CIC病理，导致损害基因组含量和皮质的有丝分裂缺陷 通过Rho-Rock和p53异常激活的细胞活力。为了测试这一点，我们将确定 生物发生，维持和消除CIC结构及其如何影响有丝分裂及其后续 基因组完整性和皮质细胞的命运（AIM1）。接下来，我们将研究PALS1删除/减少原因 通过异常的Rho-Rock激活诱惑（AIM2）。最后，我们将描述p53激活对 PALS1突变祖细胞中的CIC形成和Rho-Rock调节（AIM3）。当前的研究提供了 关于PALS1突变如何引起这种戏剧性皮质表型的重要分子和细胞线索 完全没有大脑皮层和海马。此外，我们的研究将首次 确定在皮质祖细胞中可能发生类似过程，提供一种新型的致病机制 肠细胞的蚕食会产生小头畸形。