Diseases of the primary cilia: a clinical characteristics review

Senior-Loken Syndrome: Ocular Perspectives on Genetics, Pathogenesis, and Management

Senior-Loken syndrome (SLSN) is a group of rare autosomal recessive disorders caused by dysfunction of the primary cilium, primarily affecting the kidneys (typically leading to nephronophthisis) and eyes (typically leading to retinal degeneration). Moreover, patients with SLSN may experience additional multisystemic symptoms, such as developmental delay, intellectual disability, ataxia, and nystagmus. To date, eight genes have been demonstrated to cause SLSN, all encoding for proteins involved in the structure and functions of the primary cilium. This places SLSN within an expanding category of diseases known as "ciliopathies". Due to the genetic heterogeneity and significant phenotypic overlap with other ciliopathies, establishing a definitive diagnosis during the initial consultation remains a challenge for clinicians. Furthermore, current research on SLSN-related ciliopathies predominantly focuses on renal involvement, while the ocular manifestations remain insufficiently explored and lack a comprehensive review. Therefore, with the goal of offering practical guidance for clinical practice, this review aims to provide a comprehensive overview of the clinical features, along with an ocular perspective on the molecular mechanisms, genetic underpinnings, and advances in the treatment of SLSN.

The Role of Primary Cilia in Modulating the Luteinization Process of Ovarian Granulosa Cells in Mice

The corpus luteum is the principal progesterone-secreting gland, while primary cilia function as pivotal organelles in intercellular signal transduction. Together, they play an essential role in the establishment and maintenance of pregnancy. However, the mechanisms underlying the role of primary cilia in granulosa cell luteinization in mouse ovaries remain poorly understood. This study discovered the regularity of primary cilia in mouse ovaries and revealed the role of primary cilia in regulating progesterone synthesis in luteinized granulosa cells. In vivo test results showed that the expression of primary cilia was obvious in the corpus luteum. The secretion of P4 in mice was significantly increased at 6, 12, 24, 48, and 72 h. The secretion of P4 and the expressions of luteinization markers (STAR, 3β-HSD) and primary ciliate proteins (IFT88, Arl13B) were significantly up-regulated at different time points (6, 12, 24 h and 24, 48, 72 h), and the INS group was significantly higher than the LH group and the control. In vitro test results showed that the follicular granulosa cells were luteinized under INS, the length and number of primary cilia increased, and the secretion of progesterone increased. The expression levels of STAR and 3β-HSD of the primary cilia marker Arl13B and luteinization markers were increased, while the expression levels of CYP19A1 were decreased. Ciliobrevin A (CBA) and Y-27632 2HCl were used to regulate the expression of primary cilia. The results showed that after CBA treatment, the expression level of cilia protein Arl13B decreased, and the secretion level of P4 and the expression levels of STAR and 3β-HSD decreased, indicating that the level of luteinization decreased. Conversely, after inducing ciliogenesis with Y-27632 2HCl, the results were the opposite of those observed with CBA treatment. In conclusion, our study demonstrates that primary cilia regulate the expression of steroidogenic enzymes, thereby promoting progesterone secretion by granulosa cells in mice and ensuring proper luteinization.

The role of primary cilia in myoblast proliferation and cell cycle regulation during myogenesis

The process of mammalian myogenesis is fundamental to understanding muscle development and holds broad relevance across multiple fields, from developmental biology to regenerative medicine. This review highlights two key aspects: myoblast proliferation and the role of cilia in this process. Myoblasts, as muscle precursor cells, must undergo tightly regulated cycles of proliferation and differentiation to ensure proper muscle growth and function. Recent research has uncovered an essential role for primary cilia, hair-like sensory organelles on the cell surface, in modulating signaling pathways crucial to myogenesis. Cilium-mediated signaling appears to regulate various stages of myogenesis, including the control of myoblast differentiation. Furthermore, primary cilia undergo multiple cycles of formation and disassembly during myogenesis, presumably enabling detailed, context-dependent regulation of their functions. In particular, the regulation of myoblast proliferation through cell cycle control by primary cilia is an important topic that requires further investigation. By examining the interactions between primary cilia and myoblasts, this review aims to provide new insights into the molecular and cellular mechanisms driving muscle development, with potential applications for understanding muscle-related diseases and advancing therapeutic strategies. Additionally, advancements in imaging and image analysis technologies have become indispensable for studying these processes at the cellular level. This review also addresses these technological advancements and current challenges.Key words: myogenesis, myoblast, proliferation, cilia, imaging.

Compound Heterozygous Variants in the IFT140 Gene Associated with Skeletal Ciliopathies

Ciliopathies are rare congenital disorders caused by defects in the structure or function of cilia, which can lead to a wide range of clinical manifestations. Among them, a subset known as skeletal ciliopathies exhibits significant phenotypic overlap and primarily affects skeletal development. This group includes several syndromes with overlapping but distinct clinical features, such as short-rib polydactyly syndrome (SRPS), Jeune asphyxiating thoracic dystrophy (JATD), Mainzer-Saldino syndrome (MZSDS), and cranioectodermal dysplasia (CED), also called Sensenbrenner syndrome. The most characterized features of skeletal ciliopathies are short stature, rhizomelic limb shortening, and thoracic narrowing to varying extents, with JATD presenting the most severe form. Here, we report a fetus with an extension of skeletal ciliopathy phenotype and compound heterozygous variants in the IFT140 gene. The affected fetus had multiple malformations, including increased nuchal transparency (NT), shortened and thick long bones, hypoplastic tibia and fibula, absence of bladder, flat nose, and frontal bossing. Our findings expand the mutation spectrum of IFT140, and the clinical spectrum associated with skeletal ciliopathies, highly relevant in diagnosis prenatal settings.