The role of cytoplasmic pre-assembly of axonemal components in primary ciliary dyskinesia

轴丝成分细胞质预组装在原发性纤毛运动障碍中的作用

• 批准号: 274886879
• 负责人: Professor Dr. Heymut Omran
• 金额: --
• 依托单位: Klinik für Kinder- und Jugendmedizin - Allgemeine Pädiatrie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/274886879?language=en
• 关键词: role; cytoplasmic; pre; assembly; axonemal

Primary Ciliary Dyskinesia (PCD; MIM#242650) is a genetically, functionally and on ultrastructural level heterogeneous group of rare diseases caused by dysfunction of motile cilia. Due to reduced mucociliary clearance PCD individuals suffer from chronic destructive lower and upper airway infections, which cause bronchiectasis and chronic lung failure. Other typical clinical symptoms include respiratory distress of the neonate, chronic otitis media, laterality defects of the body axis, congenital heart defects, infertility and rarely hydrocephalus. Dynein arms are necessary for ciliary motility. The components of dynein arms are first pre-assembled to a multi-protein complex in the cytoplasm of ciliated/ flagellated cells, and then delivered to the axoneme during ciliogenesis. This process is regulated by evolutionarily conserved proteins referred to as dynein axonemal assembly factors (DNAAFs).During the first funding period, we identified genetic defects in two novel DNAAFs (PIH1D3/DNAAF6 and C11orf70/CFAP300) that result in defective cytoplasmic pre-assembly of dynein arms causing ciliary immotility, disturbed mucociliary clearance of the airway, randomization of the left/right body asymmetry and male infertility. Additionally, we found that defective cytoplasmic pre-assembly of dynein arms affects sperm flagella length. By detecting mutations in PIH1D3/DNAAF6 that cause PCD, we were able to describe the first non-syndromic X-linked PCD variant. Due to randomization of X-chromosomal inactivation, we observed in female heterozygous PIH1D3/DNAAF6 mutation carriers that approx. 50% of respiratory cells show absence of dynein arms. However, so far nothing is known about the clinical status of female heterozygous mutation carriers. In terms of therapeutic approaches, it is important to find out how many respiratory cells have to be functional for effective ciliary clearance of the airways and which additional factors are involved in the cytoplasmic pre-assembly of dynein arms. Therefore, the objectives of this current proposal are as follows:1) Identification of additional families carrying mutations in PIH1D3/DNAAF6 or in other DNAAF genes2) Molecular, cellular and clinical characterization of the ciliary defect caused by mutations in PIH1D3/DNAAF6 in female carriers and hemizygous mutants and in other DNAAFs3) Characterization of the ciliary and flagellar length defects caused by disturbed cytoplasmic preassembly of dynein arms 4) Molecular and cellular characterization of novel DNAAF defects 5) Characterization of protein interactions between newly identified and known DNAAFsThe results of this proposal will i) expand knowledge of the clinical phenotype and disease course, ii) further decipher the process of cytoplasmic pre-assembly of dynein arms in respiratory as well as sperm cells, and iii) lead to the identification of new DNAAF genes. The results of this project will improve diagnostics as well as clinical care for PCD.

原发性睫状运动障碍（PCD; MIM＃242650）是一种遗传，功能和超微结构水平的异质群，由纤毛功能障碍引起的罕见疾病。由于粘膜纤毛间隙降低，PCD个体患有慢性破坏性下气道感染，导致支气管扩张和慢性肺衰竭。其他典型的临床症状包括新生儿的呼吸窘迫，慢性中耳炎，人体轴的横向缺陷，先天性心脏缺陷，不育和脑力头很少。动力蛋白臂对于睫状运动是必需的。首先将动力蛋白臂的成分预组装成纤毛/鞭毛细胞的细胞质中的多蛋白质复合物，然后在纤毛发生过程中递送至轴突。 This process is regulated by evolutionarily conserved proteins referred to as dynein axonemal assembly factors (DNAAFs).During the first funding period, we identified genetic defects in two novel DNAAFs (PIH1D3/DNAAF6 and C11orf70/CFAP300) that result in defective cytoplasmic pre-assembly of dynein arms causing ciliary immotility, disturbed气道的粘膜纤毛清除，左/右身体不对称和男性不育症的随机化。此外，我们发现动力蛋白臂的细胞质预组装有缺陷会影响精子鞭毛长度。 通过检测引起PCD的PIH1D3/DNAAF6中的突变，我们能够描述第一个非合成X连锁PCD变体。由于X染色体失活的随机化，我们在雌性杂合PIH1D3/DNAAF6突变载体中观察到。 50％的呼吸细胞表现出缺乏动力蛋白臂。但是，到目前为止，雌性杂合突变载体的临床状况尚无。就治疗方法而言，重要的是要确定必须有多少呼吸细胞起作用以有效地清除气道，以及哪些其他因素涉及的动力蛋白臂的细胞质预组装。因此，该当前建议的目的如下：1）鉴定PIH1D3/DNAAF6或其他DNAAF基因中携带突变的其他家族2）分子，细胞和临床表征是由PIH1D3/DNAAF6在Pih1d3/dnaaf6中引起的纤毛缺陷的纤毛缺陷，以及其他女性携带者和hemizygous突变体和其他DNAAFS的延迟3）的表征3） disturbed cytoplasmic preassembly of dynein arms 4) Molecular and cellular characterization of novel DNAAF defects 5) Characterization of protein interactions between newly identified and known DNAAFsThe results of this proposal will i) expand knowledge of the clinical phenotype and disease course, ii) further decipher the process of cytoplasmic pre-assembly of dynein arms in respiratory as well as sperm cells, and iii)导致鉴定新的DNAAF基因。该项目的结果将改善PCD的诊断和临床护理。