Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India.
Yenepoya Research Centre, Yenepoya (Deemed to Be University), Mangalore, India.
Exp Cell Res. 2022 Sep 15;418(2):113273. doi: 10.1016/j.yexcr.2022.113273. Epub 2022 Jul 15.
Primary cilia are non-motile sensory cell-organelle that are essential for organismal development, differentiation, and postnatal homeostasis. Their biogenesis and function are mediated by the intraflagellar transport (IFT) system. Pathogenic variants in IFT52, a central component of the IFT-B complex is associated with short-rib thoracic dysplasia with or without polydactyly 16 (SRTD16), with major skeletal manifestations, in addition to other features. Here we sought to examine the role of IFT52 in osteoblast differentiation. Using lentiviral shRNA interference Ift52 was depleted in C3H10T1/2 mouse mesenchymal stem cells. This led to the disruption of the IFT-B anterograde trafficking machinery that impaired primary ciliogenesis and blocked osteogenic differentiation. In Ift52 silenced cells, Hedgehog (Hh) pathway upregulation during osteogenesis was attenuated and despite Smoothened Agonist (SAG) based Hh activation, osteogenic differentiation was incompletely restored. Further we investigated IFT52 activity in Drosophila, wherein the only ciliated somatic cells are the bipolar sensory neurons of the peripheral nervous system. Knockdown of IFT52 in Drosophila neuronal tissues reduced lifespan with the loss of embryonic chordotonal cilia, and produced severe locomotion, auditory and proprioceptive defects in larva and adults. Together these findings improve our knowledge of the role of IFT52 in various physiological contexts and its associated human disorder.
初级纤毛是无动力的感觉细胞器官,对于生物体的发育、分化和出生后稳态至关重要。它们的生物发生和功能由鞭毛内运输(IFT)系统介导。IFT52 是 IFT-B 复合物的核心组成部分,其致病性变异与短肋胸发育不良伴或不伴多指 16 型(SRTD16)相关,主要表现为骨骼异常,此外还有其他特征。在这里,我们试图研究 IFT52 在成骨细胞分化中的作用。我们使用慢病毒 shRNA 干扰技术在 C3H10T1/2 小鼠间充质干细胞中敲低 Ift52。这导致 IFT-B 顺行运输机制的破坏,从而干扰初级纤毛发生并阻止成骨分化。在 Ift52 沉默的细胞中,成骨过程中 Hedgehog(Hh)途径的上调受到抑制,尽管存在 Smoothened 激动剂(SAG)激活 Hh,但成骨分化仍未完全恢复。进一步,我们在果蝇中研究了 IFT52 的活性,其中唯一有纤毛的体细胞是外周神经系统的双极感觉神经元。在果蝇神经元组织中敲低 IFT52 会降低寿命,丧失胚胎的 chordotonal 纤毛,并在幼虫和成虫中产生严重的运动、听觉和本体感觉缺陷。这些发现提高了我们对 IFT52 在各种生理环境中的作用及其相关人类疾病的认识。
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