Primary cilia/intraflagellar transport mediates mechanics-responsive signaling pathway and promotes osteogenic differentiation of bone marrow stromal stem cells / 中国组织工程研究

BACKGROUND:Mechanical stimulation has been confirmed to promote osteogenic differentiation of bone marrow stromal stem cells,but the mechanism is unknown.Primary cilia are important mechanoreceptors and regulate various signaling pathways such as TGF-β1/BMP-2/SMAD.They are likely to be important targets for mechanical regulation of bone marrow stromal stem cells. OBJECTIVE:To investigate the effect and mechanism of fluid shear stress on osteogenic differentiation of bone marrow stromal stem cells. METHODS:Rat bone marrow stromal stem cells were divided into control group,mechanical stimulation group(fluid shear mechanics intervention by shaking table),mechanical stimulation + IFT88 silencing group(mechanical stimulation + silencing IFT88 expression with siRNA).After 24 hours of intervention,qRT-PCR was utilized to determine the expression of transforming growth factor β1 and bone morphogenetic protein 2.Western blot assay was used to detect the expression of phosphorylated SMAD2/3 protein.Immunofluorescent staining of primary cilia was conducted and morphology was analyzed. RESULTS AND CONCLUSION:Shear stress stimulation could promote the transcriptional activity of transforming growth factor β1 and bone morphogenetic protein 2 genes,and increase the expression of phosphorylated SMAD2/3 protein.After siRNA interfered with primary cilia,this mechanical response effect was significantly reduced.There was a Spearman correlation between the change ratio of the primary cilium area of bone marrow stromal stem cells and the increased ratio of transforming growth factor β1 and bone morphogenetic protein 2 gene transcription.These findings indicate that primary cilia/intraflagellar transport mediates the activation of fluid shear stress-responsive transforming growth factor β1/bone morphogenetic protein 2/SMAD signaling pathway and promotes osteogenic differentiation of bone marrow stromal stem cells.

Loss of primary cilia promotes migration of TPC-1 in papillary thyroid cancers / 中华内分泌代谢杂志

Objective:To investigate the role of miR-182-5p regulated primary cilia loss on migration of TPC-1 in papillary thyroid cancers(PTC).Methods:Ten cases of PTC and adjacent tissues were collected from the First Hospital of Lanzhou University, The expression of miR-182-5p in PTC tissue and TPC-1 cells was detected by qPCR, and the frequency of primary cilia was detected by immunofluorescence; Overexpressing miR-182-5p, the migrated number of TPC-1 was detected by Transwell assay; Interfering TPC-1 with siRNA-IFT88, the migrated number of TPC-1 and the frequency of primary cilia were detected, respectively.Results:Compared with control, the expression of miR-182-5p was significantly upregulated in PTC and TPC-1, the frequency of primary cilia in PTC and TPC-1 was downregulated. Overexpressing miR-182-5p increased the migrated number of TPC-1 cell and reduced the number of TPC-1 cell migration(27%, P=0.002); After siRNA-IFT88 treatment, primary cilia in TPC-1 became shorter and thinner, with a decrease in frequency( P=0.001), the migrated number of TPC-1 cell increased, and TPC-1 cell showed smaller nuclei and fewer microvilli. Conclusion:The regulation of primary cilia loss by miR-182-5p through the PI3K pathway contributes to the migration of TPC-1 cells. The loss of primary cilia has an adverse impact on the prognosis of PTC.

Research progress of the INPP5E gene in primary cilium-related childhood diseases / 中华实用儿科临床杂志

The inositol polyphosphate-5-phosphatase ( INPP5E) gene encodes INPP5E, which is widely distributed in various tissues of humans and mice like the heart, brain and testis.It affects the phosphoinositide metabolic pathway by regulating the intracellular phosphatidylinositol triphosphate content, thus participating in intracellular signal transduction, cell proliferation and differentiation, cell polarity and other processes.The INPP5E gene plays a pivotal role in primary ciliogenesis and is closely related to childhood ciliary diseases.Therefore, this article review the research progress of the INPP5E gene in primary cilium-related pediatric diseases.Combined with laboratory findings, this review aims to provide new ideas for the regulation of the INPP5E gene in primary cilia and the prevention and treatment of pediatric ciliopathies.

Dynein axonemal heavy chain 10 deficiency causes primary ciliary dyskinesia in humans and mice / 医学前沿

Primary ciliary dyskinesia (PCD) is a congenital, motile ciliopathy with pleiotropic symptoms. Although nearly 50 causative genes have been identified, they only account for approximately 70% of definitive PCD cases. Dynein axonemal heavy chain 10 (DNAH10) encodes a subunit of the inner arm dynein heavy chain in motile cilia and sperm flagella. Based on the common axoneme structure of motile cilia and sperm flagella, DNAH10 variants are likely to cause PCD. Using exome sequencing, we identified a novel DNAH10 homozygous variant (c.589C > T, p.R197W) in a patient with PCD from a consanguineous family. The patient manifested sinusitis, bronchiectasis, situs inversus, and asthenoteratozoospermia. Immunostaining analysis showed the absence of DNAH10 and DNALI1 in the respiratory cilia, and transmission electron microscopy revealed strikingly disordered axoneme 9+2 architecture and inner dynein arm defects in the respiratory cilia and sperm flagella. Subsequently, animal models of Dnah10-knockin mice harboring missense variants and Dnah10-knockout mice recapitulated the phenotypes of PCD, including chronic respiratory infection, male infertility, and hydrocephalus. To the best of our knowledge, this study is the first to report DNAH10 deficiency related to PCD in human and mouse models, which suggests that DNAH10 recessive mutation is causative of PCD.

Lack of CFAP54 causes primary ciliary dyskinesia in a mouse model and human patients / 医学前沿

Primary ciliary dyskinesia (PCD) is a highly heterogeneous recessive inherited disorder. FAP54, the homolog of CFAP54 in Chlamydomonas reinhardtii, was previously demonstrated as the C1d projection of the central microtubule apparatus of flagella. A Cfap54 knockout mouse model was then reported to have PCD-relevant phenotypes. Through whole-exome sequencing, compound heterozygous variants c.2649_2657delinC (p. E883Dfs*47) and c.7312_7313insCGCAGGCTGAATTCTTGG (p. T2438delinsTQAEFLA) in a new suspected PCD-relevant gene, CFAP54, were identified in an individual with PCD. Two missense variants, c.4112A>C (p. E1371A) and c.6559C>T (p. P2187S), in CFAP54 were detected in another unrelated patient. In this study, a minigene assay was conducted on the frameshift mutation showing a reduction in mRNA expression. In addition, a CFAP54 in-frame variant knock-in mouse model was established, which recapitulated the typical symptoms of PCD, including hydrocephalus, infertility, and mucus accumulation in nasal sinuses. Correspondingly, two missense variants were deleterious, with a dramatic reduction in mRNA abundance from bronchial tissue and sperm. The identification of PCD-causing variants of CFAP54 in two unrelated patients with PCD for the first time provides strong supportive evidence that CFAP54 is a new PCD-causing gene. This study further helps expand the disease-associated gene spectrum and improve genetic testing for PCD diagnosis in the future.

Morphological and pathological changes of Eustachian tube mucosa in an animal model of eosinophilic otitis media / Alterações morfológicas e patológicas da mucosa da tuba auditiva em um modelo animal de otite média eosinofílica

Abstract Introduction Eosinophilic otitis media is an intractable otitis media and a fairly common middle ear disease. However, the pathogenesis of eosinophilic otitis media is obscure. Objective To observe the pathological and ultrastructural changes of the Eustachian tube mucosal epithelium in rats with eosinophilic otitis media and further explore the pathogenesis of eosinophilic otitis media. Methods Animals were intraperitoneally injected with 2000 mg ovalbumin and 100 mg aluminum hydroxide (alum) on day 0, followed by 100 mg ovalbumin and 100 mg alum injection on days 7 and 14. Next they were topically boosted by daily application of 100 mg ovalbumin solution via nasal drip and intratympanic injection of 0.1 mL ovalbumin (1000 mg/mL) in the right ear (group A, n = 80) and 0.1 mL saline in the left ear as control (group B, n = 80) starting on day 21 and continuing for 14 days. The temporal bones were dissected on the 35th, 38th, 41st and 43rd day separately under anesthesia. Scanning electron microscopy, hematoxylin-eosin and toluidine blue staining were used to observe the pathological and morphological changes of Eustachian tube mucosa stained samples. Moreover, inflammatory cells and cilia were counted. Results The epithelium of the Eustachian tube in group A was swollen and thickened. The cilia were arranged in a disorderly manner and partially detached. Eosinophils infiltrated the submucosal layer of the Eustachian tube, and their number increased significantly compared with that in group B (p< 0.05). Simultaneously, mast cell degranulation was observed in group A. Scanning electron microscopy revealed that the cilia were lodged and gathered along the whole length of Eustachian tube in group A. Ciliated cell density was significantly lower than that in Group B (p< 0.01). Conclusion In the eosinophilic otitis media model, allergy caused significant changes in pathology and morphology of the Eustachian tube mucosa, affecting the normal function of the Eustachian tube which played an important role in the occurrence and development of eosinophilic otitis media.

Resumo Introdução A otite média eosinofílica é uma doença relativamente comum de orelha média; entretanto, sua patogênese é ainda obscura, assim como o tratamento. Objetivo Observar as alterações histopatológicas e ultraestruturais do epitélio da mucosa da tuba auditiva em ratos com otite média eosinofílica e investigar a sua patogênese. Método Os animais foram injetados intraperitonealmente com 2.000 mg de ovalbumina e 100 mg de hidróxido de alumínio (alúmen) no dia 0, seguido por 100 mg de ovalbumina e 100 mg de injeção de alúmen nos dias 7 e 14. Em seguida, receberam um reforço tópico através de uma aplicação diária de 100 mg da solução por gotejamento nasal e injeção intratimpânica de 0,1 mL de ovalbumina (1000 mg/mL) na orelha direita (grupo A, n = 80) e 0,1 mL de solução salina na orelha esquerda como controle (grupo B, n = 80), começou no dia 21 e continuou por 14 dias. Os ossos temporais foram dissecados nos dias 35, 38, 41 e 43 separadamente sob anestesia. Foram usadas microscopia eletrônica de varredura e coloração com hematoxilina-eosina e azul de toluidina para observar as alterações histopatológicas e morfológicas das amostras coradas de mucosa da tuba auditiva. Além disso, células inflamatórias e cílios foram contados. Resultados O epitélio da tuba auditiva no grupo A estava edematoso e espessado. Os cílios estavam dispostos de forma desordenada e parcialmente destacados. Os eosinófilos infiltraram a camada submucosa da tuba auditiva e seu número aumentou significantemente em comparação ao grupo B (p < 0,05). Simultaneamente, degranulação dos mastócitos foi observado no grupo A. A microscopia eletrônica de varredura mostrou que os cílios estavam depositados e reunidos ao longo de todo o comprimento da tuba auditiva no grupo A. A densidade das células ciliadas foi significantemente menor do que no grupo B (p < 0,01). Conclusão No modelo de otite média eosinofílica, a alergia causou alterações significativas à histopatologia e na morfologia da mucosa da tuba auditiva, afetou a função normal dela, o que desempenhou um papel importante na ocorrência e no desenvolvimento da otite média eosinofílica.

Advance in role of cilia in the pathogenesis of congenital heart disease / 国际儿科学杂志

Congenital heart disease(CHD)is one of the most common genetic diseases, mainly refers to the abnormal cardiovascular development caused by various abnormal factors during fetal development.Studies have found that the normal development of cardiovascular functional structure requires accurate positioning of the left-right asymmetry.As an essential link in body material metabolism and signal-transducing mechanism, cilia may participate in the pathogenesis of CHD by affecting the distribution of the left-right asymmetry of human organs and tissues during embryonic development.Therefore, a thorough understanding of the role, molecular mechanism, and related regulatory genes of cilia in CHD can provide accurate diagnosis and treatment for clinical work to obtain a better prognosis.Here we review the effects of cilia on the positioning of the left-right asymmetry during embryo development and its role in the pathogenesis of CHD.

Inhibition of Ciliogenesis Enhances the Cellular Sensitivity to Temozolomide and Ionizing Radiation in Human Glioblastoma Cells / 生物医学与环境科学（英文）

Objective@#To investigate the function of primary cilia in regulating the cellular response to temozolomide (TMZ) and ionizing radiation (IR) in glioblastoma (GBM).@*Methods@#GBM cells were treated with TMZ or X-ray/carbon ion. The primary cilia were examined by immunostaining with Arl13b and γ-tubulin, and the cellular resistance ability was measured by cell viability assay or survival fraction assay. Combining with cilia ablation by IFT88 depletion or chloral hydrate and induction by lithium chloride, the autophagy was measured by acridine orange staining assay. The DNA damage repair ability was estimated by the kinetic curve of γH2AX foci, and the DNA-dependent protein kinase (DNA-PK) activation was detected by immunostaining assay.@*Results@#Primary cilia were frequently preserved in GBM, and the induction of ciliogenesis decreased cell proliferation. TMZ and IR promoted ciliogenesis in dose- and time-dependent manners, and the suppression of ciliogenesis significantly enhanced the cellular sensitivity to TMZ and IR. The inhibition of ciliogenesis elevated the lethal effects of TMZ and IR via the impairment of autophagy and DNA damage repair. The interference of ciliogenesis reduced DNA-PK activation, and the knockdown of DNA-PK led to cilium formation and elongation.@*Conclusion@#Primary cilia play a vital role in regulating the cellular sensitivity to TMZ and IR in GBM cells through mediating autophagy and DNA damage repair.

Primary cilium and its role in tumorigenesis / 浙江大学学报·医学版

The primary cilium, a sensory organelle that protrudes from the surface of most eukaryotic cells, receives and transduces various critical signals that are essential for normal development and homeostasis. Structural or functional disruption of primary cilia causes a number of human diseases, including cancer. Primary cilia has cross talks with cell cycle and it may act as a cell cycle checkpoint to suppress cancer development. Moreover, primary cilia has cross-regulation with autophagy, which may affect tumor progression. We then discuss the association of the primary cilia with several oncogenic signaling pathways, including Shh, Wnt, Notch and platelet-derived growth factor receptor (PDGFR). Since these signaling pathways are often over-activated in many types of human cancers, primary cilia are likely to play a role in the tumorigenesis by modulating these pathways. Finally, we summarize current progress on the role of cilia during tumorigenesis and the challenges that the cilia-cancer field faces.

Axonemal Dynein DNAH5 is Required for Sound Sensation in Drosophila Larvae / 神经科学通报·英文版

Chordotonal neurons are responsible for sound sensation in Drosophila. However, little is known about how they respond to sound with high sensitivity. Using genetic labeling, we found one of the Drosophila axonemal dynein heavy chains, CG9492 (DNAH5), was specifically expressed in larval chordotonal neurons and showed a distribution restricted to proximal cilia. While DNAH5 mutation did not affect the cilium morphology or the trafficking of Inactive, a candidate auditory transduction channel, larvae with DNAH5 mutation had reduced startle responses to sound at low and medium intensities. Calcium imaging confirmed that DNAH5 functioned autonomously in chordotonal neurons for larval sound sensation. Furthermore, disrupting DNAH5 resulted in a decrease of spike firing responses to low-level sound in chordotonal neurons. Intriguingly, DNAH5 mutant larvae displayed an altered frequency tuning curve of the auditory organs. All together, our findings support a critical role of DNAH5 in tuning the frequency selectivity and the sound sensitivity of larval auditory neurons.

Novel biallelic loss-of-function mutations in / 亚洲男科学杂志(英文版)

Multiple morphological abnormalities of the sperm flagella (MMAF) is a specific type of asthenoteratozoospermia, presenting with multiple morphological anomalies in spermatozoa, such as absent, bent, coiled, short, or irregular caliber flagella. Previous genetic studies revealed pathogenic mutations in genes encoding cilia and flagella-associated proteins (CFAPs; e.g., CFAP43, CFAP44, CFAP65, CFAP69, CFAP70, and CFAP251) responsible for the MMAF phenotype in infertile men from different ethnic groups. However, none of them have been identified in infertile Pakistani males with MMAF. In the current study, two Pakistani families with MMAF patients were recruited. Whole-exome sequencing (WES) of patients and their parents was performed. WES analysis reflected novel biallelic loss-of-function mutations in CFAP43 in both families (Family 1: ENST00000357060.3, p.Arg300Lysfs*22 and p.Thr526Serfs*43 in a compound heterozygous state; Family 2: ENST00000357060.3, p.Thr526Serfs*43 in a homozygous state). Sanger sequencing further confirmed that these mutations were segregated recessively in the families with the MMAF phenotype. Semiquantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) was carried out to detect the effect of the mutation on mRNA of the affected gene. Previous research demonstrated that biallelic loss-of-function mutations in CFAP43 accounted for the majority of all CFAP43-mutant MMAF patients. To the best of our knowledge, this is the first study to report CFAP43 biallelic loss-of-function mutations in a Pakistani population with the MMAF phenotype. This study will help researchers and clinicians to understand the genetic etiology of MMAF better.

Primary cilia in hard tissue development and diseases / 医学前沿

Bone and teeth are hard tissues. Hard tissue diseases have a serious effect on human survival and quality of life. Primary cilia are protrusions on the surfaces of cells. As antennas, they are distributed on the membrane surfaces of almost all mammalian cell types and participate in the development of organs and the maintenance of homeostasis. Mutations in cilium-related genes result in a variety of developmental and even lethal diseases. Patients with multiple ciliary gene mutations present overt changes in the skeletal system, suggesting that primary cilia are involved in hard tissue development and reconstruction. Furthermore, primary cilia act as sensors of external stimuli and regulate bone homeostasis. Specifically, substances are trafficked through primary cilia by intraflagellar transport, which affects key signaling pathways during hard tissue development. In this review, we summarize the roles of primary cilia in long bone development and remodeling from two perspectives: primary cilia signaling and sensory mechanisms. In addition, the cilium-related diseases of hard tissue and the manifestations of mutant cilia in the skeleton and teeth are described. We believe that all the findings will help with the intervention and treatment of related hard tissue genetic diseases.

Mechanism of highly expressed primary cilia in tibial growth plate chondrocyte accelerating chondrocyte differentiation in young rats with chronic renal failure / 中华肾脏病杂志

Objective:To explore the mechanism of highly expressed primary cilia in tibial growth plate chondrocytes accelerating chondrocytes differentiation in young rats with chronic renal failure (CRF).Methods:Forty male 4-week-old SD rats weighing (98±3) g were randomly divided into control group (intragastric administration with distilled water, n=20) and CRF group (intragastric administration with adenine suspension 150 mg·kg -1·d -1, n=20). All the young rats were sacrificed after continuous gavage for 6 weeks. The length of the growth plate was measured with histological sections. Immunofluorescence (IF) was used to detect the expression rate of primary cilia and the level of β-catenin, the key protein of Wnt/β-catenin signaling pathway in tibial growth plate chondrocytes. Chondrocytes isolated from growth plate in two groups were cultured in vitro to P3 generation, and the expression rate of primary cilia in chondrocytes, the levels of Indian hedgehog (IHH) and glycogen synthase kinase 3β (GSK3β) were detected by IF. Co-immunoprecipitation was used to detect the relationship between IHH and GSK3β. Results:Compared with the control group, the relative length of the growth plate was shorter in histological sections [(0.51±0.11) vs (1.00±0.08), t=16.11, P<0.001], the expression rate of primary cilia was higher [(26.3±5.5)% vs (7.6±1.9)%, t=14.37, P<0.001], and the level of β-catenin increased [(7.1±2.0) scores vs (3.6±1.0) scores, t=7.10, P<0.001] in CRF group. In vitro, the expression rate of primary cilia was higher in CRF group chondrocytes [(31.4±8.2)% vs (12.5±3.1)%, t=9.64, P<0.001] than that in control group. The level of IHH in CRF group increased than that in control group [(1 360±270) vs (310±84), t=16.61, P<0.001]. There was no significant difference in GSK3β level of chondrocytes between the two groups [(850±195) vs (780±140), t=1.30, P=0.200]. There was a direct interaction between IHH and GSK3β in CRF group chondrocytes. Conclusions:The expression levels of primary cilia and related protein IHH increase in tibial growth plate chondrocytes of CRF young rats. The IHH protein plays a direct interaction with GSK3β protein, Wnt/β-catenin signaling pathway antagonist, which leads to the activation of Wnt/β-catenin signaling pathway and final accelerated differentiation of chondrocytes. The rapid differentiation of chondrocytes causes the closing trend of growth plate.

Freeing the brake: Proliferation needs primary cilium to disassemble

Primary cilia are non-motile, microtubule-based, antennae-like organelle that protrude out from the cell surfaceand perform sensory function or transduce physiological signals in majority of the vertebrate cells. Cilia areassembled on basal bodies that are transformed centrioles. The assembly-disassembly of primary cilia maypose an additional measure on regulating cell cycle in vertebrate cells. While primary cilia are commonly foundin differentiated or quiescent cells that are not cycling, disassembly of primary cilia may promote re-entry ofthese cells into the mitotic cycle, and support proliferation. Many cancer tissues or cancer-derived cells exhibitloss of primary cilia. However, primary cilia may also promote tumorigenesis in some contexts throughgrowth-promoting signalling. This review will shed light on recent advancements of temporal coordination ofciliary disassembly and cell cycle progression, with a focus on how cilia loss may support tumorigenesis invarious epithelial cancers

Roles of Cilia in Heart Development and Congenital Heart Disease / 中国医学科学院学报

Cilia are protruding cell structures on the cell surface and are found in almost every type of cell.According to the different structures and quantity of tubulins,cilia can be divided into two categories:motor cilia and sensory cilia.Sensory cilia are also called non-motor cilia and primary cilia,due to the composition and number of tubulins.They are closely related to the development of internal organs and many human physiological activities.Recent studies have demonstrated that cilia are involved in regulating the formation of left and right symmetry of the heart structure,and eventually the heart develops into the left-right asymmetry structures.Since congenital heart diseases(CHD)are characterized by abnormalities in the spatial structure of the heart chamber and outflow tract,cilia may play an important role in the pathogenesis of CHD.Cilia,mainly through ciliary transduction signal pathways,regulate both the formation of left and right asymmetrical structures and the polarity and the migration of cells.Therefore,a clear understanding of the regulation mechanism of ciliary signaling pathway on heart development can provide new therapeutic targets and new ideas for the clinical treatment of CHD and may offer new target genes for prenatal screening of CHD.This article summarizes recent advances in the role of cilia in heart development and CHD pathogenesis and its mechanisms.

Progress in pathogenesis, diagnosis, and treatment of Alstrom syndrome / 国际儿科学杂志

Alstrom syndrome(ALMS)is a rare autosomal recessive disorder involving multiple systems.The main clinical manifestations include nystagmus, hearing loss, obesity, insulin resistance, type 2 diabetes, dilated cardiomyopathy, etc.Primary cilia are key organelles.ALMS is classified as a ciliopathy, mainly related to the mutation of ALMS1 gene which affects cilia function, but the specific mechanism remains unclear.At present, the diagnosis of ALMS mainly relies on clinical manifestations and gene sequencing.There are no specific and effective treatment methods except for symptomatic treatment, but early diagnosis and intervention can delay disease progression and improve patients′ quality of life.This article reviews recent advances in the pathogenesis, diagnosis, and treatment of ALMS.

Biomechanical Effects of Primary Cilia in Articular Cartilage / 医用生物力学

Biomechanical factors play a crucial role in the steady-state maintenance of articular cartilage. The primary cilium (PC) is a kind of organelle which can sense mechanical and chemical signals at the same time. It is also distributed on the surface of chondrocyte membrane. It is involved in multiple signal transduction pathways as well as in the process of chondrocyte phenotype maintenance and material metabolism. Abnormalities in PC are also associated with a variety of human bone and joint diseases. This paper mainly discusses the mechanism of PC in mechanical microenvironment of chondrocytes and the interaction with other signaling pathways, and explores its relationship with bone and joint diseases, so as to provide some scientific basis for clinical and basic research in orthopedics.

Progress in pathogenesis, diagnosis, and treatment of Alstrom syndrome / 国际儿科学杂志

Alstrom syndrome (ALMS) is a rare autosomal recessive disorder involving multiple systems.The main clinical manifestations include nystagmus,hearing loss,obesity,insulin resistance,type 2 diabetes,dilated cardiomyopathy,etc.Primary cilia are key organelles.ALMS is classified as a ciliopathy,mainly related to the mutation of ALMS1 gene which affects cilia function,but the specific mechanism remains unclear.At present,the diagnosis of ALMS mainly relies on clinical manifestations and gene sequencing.There are no specific and effective treatment methods except for symptomatic treatment,but early diagnosis and intervention can delay disease progression and improve patients' quality of life.This article reviews recent advances in the pathogenesis,diagnosis,and treatment of ALMS.

Research progress on the distribution of primary cilia and related signaling pathways involved in odontogenesis / 口腔疾病防治

@#Primary cilia are organelles present on most mammalian cells that sense environmental changes and transduce signaling, and they are the key coordinators of various signaling pathways during tissue development. This article reviews the progress of research on the distribution of primary cilia in tooth development and the related signaling pathways. A literature review shows that in odontogenesis, primary cilia play an important role in the mutual induction of the epithelium and mesenchyme; during the continuous proliferation and differentiation of cells, the distribution of primary cilia is temporally and spatially dependent. Although the reason for this distribution is still unclear, some experimental evidence indicates that this phenomenon is compatible with the function of cells and tissues in which primary cilia are distributed. Primary cilia are involved in the regulation of two important signaling pathways, Hedgehog and Wnt, in odontogenesis. Genes encoding cilia (such as Kif3a, Evc/Evc2 and Ift) can affect the development of teeth by regulating these two signaling pathways, and there is an interaction between the two signaling pathways. Deletion of related genes (such as Ofd1 and Bbs) can damage the transmission of upstream and downstream signals by damaging the structure or function of cilia, thereby causing various types of dental dysplasia, including small teeth, enamel hypoplasia, missing teeth, or craniofacial deformities.

Primary cilia mediate Klf2-dependant Notch activation in regenerating heart

Unlike adult mammalian heart, zebrafish heart has a remarkable capacity to regenerate after injury. Previous study has shown Notch signaling activation in the endocardium is essential for regeneration of the myocardium and this activation is mediated by hemodynamic alteration after injury, however, the molecular mechanism has not been fully explored. In this study we demonstrated that blood flow change could be perceived and transmitted in a primary cilia dependent manner to control the hemodynamic responsive klf2 gene expression and subsequent activation of Notch signaling in the endocardium. First we showed that both homologues of human gene KLF2 in zebrafish, klf2a and klf2b, could respond to hemodynamic alteration and both were required for Notch signaling activation and heart regeneration. Further experiments indicated that the upregulation of klf2 gene expression was mediated by endocardial primary cilia. Overall, our findings reveal a novel aspect of mechanical shear stress signal in activating Notch pathway and regulating cardiac regeneration.