Institute of Health and Medicine Division of Reproduction and Genetics, The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Sciences and Medicine, Hefei Comprehensive National Science CenterFirst Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at MicroscaleBiomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, 230027, China.
Gomal Centre of Biochemistry and Biotechnology, Gomal University, Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan.
Mol Genet Genomics. 2024 Jul 12;299(1):69. doi: 10.1007/s00438-024-02161-2.
TTC12 is a cytoplasmic and centromere-localized protein that plays a role in the proper assembly of dynein arm complexes in motile cilia in both respiratory cells and sperm flagella. This finding underscores its significance in cellular motility and function. However, the wide role of TTC12 in human spermatogenesis-associated primary ciliary dyskinesia (PCD) still needs to be elucidated. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify potentially pathogenic variants causing PCD and multiple morphological abnormalities of sperm flagella (MMAF) in an infertile Pakistani man. Diagnostic imaging techniques were used for PCD screening in the patient. Real-time polymerase chain reaction (RT‒PCR) was performed to detect the effect of mutations on the mRNA abundance of the affected genes. Papanicolaou staining and scanning electron microscopy (SEM) were carried out to examine sperm morphology. Transmission electron microscopy (TEM) was performed to examine the ultrastructure of the sperm flagella, and the results were confirmed by immunofluorescence staining. Using WES and Sanger sequencing, a novel homozygous missense variant (c.C1069T; p.Arg357Trp) in TTC12 was identified in a patient from a consanguineous family. A computed tomography scan of the paranasal sinuses confirmed the symptoms of the PCD. RT-PCR showed a decrease in TTC12 mRNA in the patient's sperm sample. Papanicolaou staining, SEM, and TEM analysis revealed a significant change in shape and a disorganized axonemal structure in the sperm flagella of the patient. Immunostaining assays revealed that TTC12 is distributed throughout the flagella and is predominantly concentrated in the midpiece in normal spermatozoa. In contrast, spermatozoa from patient deficient in TTC12 showed minimal staining intensity for TTC12 or DNAH17 (outer dynein arms components). This could lead to MMAF and result in male infertility. This novel TTC12 variant not only illuminates the underlying genetic causes of male infertility but also paves the way for potential treatments targeting these genetic factors. This study represents a significant advancement in understanding the genetic basis of PCD-related infertility.
TTC12 是一种细胞质和着丝粒定位蛋白，在呼吸细胞和精子鞭毛的能动纤毛中，dynin 臂复合物的正确组装中发挥作用。这一发现强调了它在细胞运动和功能中的重要性。然而，TTC12 在人类与精子发生相关的原发性纤毛运动障碍（PCD）中的广泛作用仍需要阐明。对一名不育的巴基斯坦男性进行了全外显子组测序（WES）和 Sanger 测序，以鉴定导致 PCD 和精子鞭毛多种形态异常（MMAF）的潜在致病性变异。使用诊断成像技术对患者进行 PCD 筛查。进行实时聚合酶链反应（RT-PCR）以检测突变对受影响基因的 mRNA 丰度的影响。进行巴氏染色和扫描电子显微镜（SEM）检查以检查精子形态。进行透射电子显微镜（TEM）检查以检查精子鞭毛的超微结构，并通过免疫荧光染色进行验证。使用 WES 和 Sanger 测序，在一个来自近亲家庭的患者中鉴定出 TTC12 中的一种新型纯合错义变异（c.C1069T；p.Arg357Trp）。对副鼻窦的计算机断层扫描证实了 PCD 的症状。RT-PCR 显示患者精子样本中的 TTC12 mRNA 减少。巴氏染色、SEM 和 TEM 分析显示患者精子鞭毛的形状发生了显著变化，轴丝结构紊乱。免疫染色测定显示 TTC12 分布在整个鞭毛中，在正常精子中主要集中在中段。相比之下，TTC12 缺乏的患者的精子显示出 TTC12 或 DNAH17（外动力臂成分）的染色强度最小。这可能导致 MMAF 并导致男性不育。这种新型 TTC12 变体不仅阐明了男性不育的潜在遗传原因，还为针对这些遗传因素的潜在治疗方法铺平了道路。这项研究代表了对 PCD 相关不育症遗传基础的理解的重大进展。
