scholarly journals Galectin 3 Deficiency Alters Chondrocyte Primary Cilium Formation and Exacerbates Cartilage Destruction via Mitochondrial Apoptosis

2020 ◽  
Vol 21 (4) ◽  
pp. 1486 ◽  
Author(s):  
Narjès Hafsia ◽  
Marine Forien ◽  
Félix Renaudin ◽  
Delphine Delacour ◽  
Pascal Reboul ◽  
...  
Keyword(s):  
Primary Cilium ◽  
Primary Cilia ◽  
Mitochondrial Pathway ◽  
Cartilage Destruction ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Chondrocyte Apoptosis ◽  
Cytochrome C Release ◽  
Cilium Formation ◽  
Galectin 3

Mechanical overload and aging are the main risk factors of osteoarthritis (OA). Galectin 3 (GAL3) is important in the formation of primary cilia, organelles that are able to sense mechanical stress. The objectives were to evaluate the role of GAL3 in chondrocyte primary cilium formation and in OA in mice. Chondrocyte primary cilium was detected in vitro by confocal microscopy. OA was induced by aging and partial meniscectomy of wild-type (WT) and Gal3-null 129SvEV mice (Gal3−/−). Primary chondrocytes were isolated from joints of new-born mice. Chondrocyte apoptosis was assessed by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), caspase 3 activity and cytochrome c release. Gene expression was assessed by qRT-PCR. GAL3 was localized at the basal body of the chondrocyte primary cilium. Primary cilia of Gal3−/− chondrocytes were frequently abnormal and misshapen. Deletion of Gal3 triggered premature OA during aging and exacerbated joint instability-induced OA. In both aging and surgery-induced OA cartilage, levels of chondrocyte catabolism and hypertrophy markers and apoptosis were more severe in Gal3−/− than WT samples. In vitro, Gal3 knockout favored chondrocyte apoptosis via the mitochondrial pathway. GAL3 is a key regulator of cartilage homeostasis and chondrocyte primary cilium formation in mice. Gal3 deletion promotes OA development.

scholarly journals Disruption of Dhcr7 and Insig1/2 in cholesterol metabolism causes defects in bone formation and homeostasis through primary cilium formation

Bone Research ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Akiko Suzuki ◽  
Kenichi Ogata ◽  
Hiroki Yoshioka ◽  
Junbo Shim ◽  
Christopher A. Wassif ◽  
...  
Keyword(s):  
Bone Formation ◽  
Primary Cilium ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Cilium Formation ◽  
Intracellular Cholesterol

AbstractHuman linkage studies suggest that craniofacial deformities result from either genetic mutations related to cholesterol metabolism or high-cholesterol maternal diets. However, little is known about the precise roles of intracellular cholesterol metabolism in the development of craniofacial bones, the majority of which are formed through intramembranous ossification. Here, we show that an altered cholesterol metabolic status results in abnormal osteogenesis through dysregulation of primary cilium formation during bone formation. We found that cholesterol metabolic aberrations, induced through disruption of either Dhcr7 (which encodes an enzyme involved in cholesterol synthesis) or Insig1 and Insig2 (which provide a negative feedback mechanism for cholesterol biosynthesis), result in osteoblast differentiation abnormalities. Notably, the primary cilia responsible for sensing extracellular cues were altered in number and length through dysregulated ciliary vesicle fusion in Dhcr7 and Insig1/2 mutant osteoblasts. As a consequence, WNT/β-catenin and hedgehog signaling activities were altered through dysregulated primary cilium formation. Strikingly, the normalization of defective cholesterol metabolism by simvastatin, a drug used in the treatment of cholesterol metabolic aberrations, rescued the abnormalities in both ciliogenesis and osteogenesis in vitro and in vivo. Thus, our results indicate that proper intracellular cholesterol status is crucial for primary cilium formation during skull formation and homeostasis.

scholarly journals A Model for Primary Cilium Biogenesis by Polarized Epithelial Cells: Role of the Midbody Remnant and Associated Specialized Membranes

2021 ◽  
Vol 8 ◽  
Author(s):  
Leticia Labat-de-Hoz ◽  
Armando Rubio-Ramos ◽  
Javier Casares-Arias ◽  
Miguel Bernabé-Rubio ◽  
Isabel Correas ◽  
...  
Keyword(s):  
Cell Surface ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Control Cell ◽  
Future Research ◽  
Alternative Route ◽  
Ciliary Membrane ◽  
Cilium Formation ◽  
Membrane Compartmentalization

Primary cilia are solitary, microtubule-based protrusions surrounded by a ciliary membrane equipped with selected receptors that orchestrate important signaling pathways that control cell growth, differentiation, development and homeostasis. Depending on the cell type, primary cilium assembly takes place intracellularly or at the cell surface. The intracellular route has been the focus of research on primary cilium biogenesis, whereas the route that occurs at the cell surface, which we call the “alternative” route, has been much less thoroughly characterized. In this review, based on recent experimental evidence, we present a model of primary ciliogenesis by the alternative route in which the remnant of the midbody generated upon cytokinesis acquires compact membranes, that are involved in compartmentalization of biological membranes. The midbody remnant delivers part of those membranes to the centrosome in order to assemble the ciliary membrane, thereby licensing primary cilium formation. The midbody remnant's involvement in primary cilium formation, the regulation of its inheritance by the ESCRT machinery, and the assembly of the ciliary membrane from the membranes originally associated with the remnant are discussed in the context of the literature concerning the ciliary membrane, the emerging roles of the midbody remnant, the regulation of cytokinesis, and the role of membrane compartmentalization. We also present a model of cilium emergence during evolution, and summarize the directions for future research.

scholarly journals Apoptosis of Growth Plate Chondrocytes Occurs through a Mitochondrial Pathway

2007 ◽  
Vol 77 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Cristina C. Teixeira ◽  
Aida P. Padron Costas ◽  
Yelena Nemelivsky
Keyword(s):  
Cytochrome C ◽  
Growth Plate ◽  
Caspase 3 ◽  
Mitochondrial Pathway ◽  
Chondrocyte Apoptosis ◽  
Cytochrome C Release ◽  
Growth Plate Chondrocytes ◽  
Chondrocyte Viability ◽  
Induced Apoptosis ◽  
Free Media

Abstract Objective: To determine the role of mitochondria in chondrocyte apoptosis induced by inorganic phosphate (Pi). Materials and Methods: Chondrocytes isolated from the growth plates of chick embryo tibia were treated with Pi in serum-free media; chondrocyte viability, mitochondrial membrane potential, cytochrome c release from mitochondria, caspase 3 activity, endonuclease activity, and DNA fragmentation were investigated. Results: Exposure to Pi for 24 hours induced apoptosis in growth plate chondrocytes through a pathway that involved loss of mitochondrial function, release of cytochrome c into the cytoplasm, increases in caspase 3 and endonuclease activities, and fragmentation of DNA. Conclusions: This study suggests that mitochondria are important players in Pi-induced apoptosis.

scholarly journals Triptolide induces caspase-dependent cell death mediated via the mitochondrial pathway in leukemic cells

Blood ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 630-637 ◽  
Author(s):  
Bing Z. Carter ◽  
Duncan H. Mak ◽  
Wendy D. Schober ◽  
Teresa McQueen ◽  
David Harris ◽  
...  
Keyword(s):  
Cell Death ◽  
Anticancer Agents ◽  
Chinese Herb ◽  
Mitochondrial Pathway ◽  
Leukemic Cells ◽  
Cytochrome C Release ◽  
Knock Out ◽  
Dependent Cell ◽  
Induced Apoptosis

Triptolide, a diterpenoid isolated from the Chinese herb Tripterygium wilfordii Hook.f, has shown antitumor activities in a broad range of solid tumors. Here, we examined its effects on leukemic cells and found that, at 100 nM or less, it potently induced apoptosis in various leukemic cell lines and primary acute myeloid leukemia (AML) blasts. We then attempted to identify its mechanisms of action. Triptolide induced caspase-dependent cell death accompanied by a significant decrease in XIAP levels. Forced XIAP overexpression attenuated triptolide-induced cell death. Triptolide also decreased Mcl-1 but not Bcl-2 and Bcl-XL levels. Bcl-2 overexpression suppressed triptolide-induced apoptosis. Further, triptolide induced loss of the mitochondrial membrane potential and cytochrome C release. Caspase-9 knock-out cells were resistant, while caspase-8–deficient cells were sensitive to triptolide, suggesting criticality of the mitochondrial but not the death receptor pathway for triptolide-induced apoptosis. Triptolide also enhanced cell death induced by other anticancer agents. Collectively, our results demonstrate that triptolide decreases XIAP and potently induces caspase-dependent apoptosis in leukemic cells mediated through the mitochondrial pathway at low nanomolar concentrations. The potent antileukemic activity of triptolide in vitro warrants further investigation of this compound for the treatment of leukemias and other malignancies.

scholarly journals Actinomycin V Induces Apoptosis Associated with Mitochondrial and PI3K/AKT Pathways in Human CRC Cells

Marine Drugs ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. 599
Author(s):  
Shiqing Jiang ◽  
E Zhang ◽  
Hang Ruan ◽  
Jiahui Ma ◽  
Xingming Zhao ◽  
...  
Keyword(s):  
Mitochondrial Pathway ◽  
Potential Candidate ◽  
Cytochrome C Release ◽  
Pi3k Inhibitor Ly294002 ◽  
Mitochondria Membrane Potential ◽  
Pi3k Inhibition ◽  
Hct 116 ◽  
Hct 116 Cells ◽  
Induced Apoptosis

Actinomycin (Act) V, an analogue of Act D, presented stronger antitumor activity and less hepatorenal toxicity than Act D in our previous studies, which is worthy of further investigation. We hereby report that Act V induces apoptosis via mitochondrial and PI3K/AKT pathways in colorectal cancer (CRC) cells. Act V-induced apoptosis was characterized by mitochondrial dysfunction, with loss of mitochondria membrane potential (MMP) and cytochrome c release, which then activated cleaved caspase-9, cleaved caspase-3, and cleaved PARP, revealing that it was related to the mitochondrial pathway, and the apoptotic trendency can be reversed by caspase inhibitor Z-VAD-FMK. Furthermore, we proved that Act V significantly inhibited PI3K/AKT signalling in HCT-116 cells using cell experiments in vitro, and it also presented a potential targeted PI3Kα inhibition using computer docking models. Further elucidation revealed that it exhibited a 28-fold greater potency than the PI3K inhibitor LY294002 on PI3K inhibition efficacy. Taken together, Act V, as a superior potential replacement of Act D, is a potential candidate for inhibiting the PI3K/AKT pathway and is worthy of more pre-clinical studies in the therapy of CRC.

scholarly journals The primary cilium dampens proliferative signaling and represses a G2/M transcriptional network in quiescent myoblasts

2020 ◽  
Author(s):  
Nisha Venugopal ◽  
Ananga Ghosh ◽  
Hardik Gala ◽  
Ajoy Aloysius ◽  
Neha Vyas ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Primary Cilium ◽  
Developmental Disorders ◽  
Adult Stem Cells ◽  
Primary Cilia ◽  
Translational Repressor ◽  
Elevated Protein ◽  
Proliferative Signaling

Abstract Background Reversible cell cycle arrest (quiescence/G0) is characteristic of adult stem cells and is actively controlled at multiple levels. Quiescent cells also extend a primary cilium, which functions as a signaling hub. Primary cilia have been shown to be important in multiple developmental processes, and are implicated in numerous developmental disorders. Although the association of the cilium with G0 is established, the role of the cilium in the control of the quiescence program is still poorly understood. Results Primary cilia are dynamically regulated across different states of cell cycle exit in skeletal muscle myoblasts: quiescent myoblasts elaborate a primary cilium in vivo and in vitro , but terminally differentiated myofibers do not. Myoblasts where ciliogenesis is ablated using RNAi against a key ciliary assembly protein (IFT88) can exit the cell cycle but display an altered quiescence program and impaired self-renewal. Specifically, the G0 transcriptome in IFT88 knockdown cells is aberrantly enriched for G2/M regulators, suggesting a focused repression of this network by the cilium. Cilium-ablated cells also exhibit features of activation including enhanced activity of Wnt and mitogen signaling and elevated protein synthesis via inactivation of the translational repressor 4E-BP1. Conclusions Taken together, our results show that the primary cilium integrates and dampens proliferative signaling, represses translation and G2/M genes, and is integral to the establishment of the quiescence program.

AICAR Induces Apoptosis in Chronic Lymphocytic Leukemia Cells through the Mitochondrial Pathway and Independently of p53 Pathway and AMPK Activation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4819-4819
Author(s):  
Joan Gil ◽  
Antonio F Santidrián ◽  
Diana M González-Gironès ◽  
Daniel Iglesias-Serret ◽  
Llorenç Coll-Mulet ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Lymphocytes ◽  
Mitochondrial Pathway ◽  
Lymphocytic Leukemia ◽  
Mrna Levels ◽  
Ampk Activation ◽  
Cytochrome C Release ◽  
Cell Technologies ◽  
Induced Apoptosis

Abstract Abstract 4819 AICAR (5-aminoimidazole-4-carboxamide riboside or acadesine) induces apoptosis in different cell types including chronic lymphocytic leukemia (CLL) cells. Here, we have analyzed the mechanisms involved in AICAR-induced apoptosis in CLL cells. AICAR induced apoptosis through the mitochondrial pathway, since inhibition of caspase-8 did not protect CLL cells from AICAR-induced apoptosis and caspase inhibition did not alter cytochrome c release induced by AICAR. AICAR induced a significant increase in the mRNA levels of the proapoptotic BH3-only genes BIM, BNIP3, BNIP3L, HRK, MOAP1, and NOXA. These changes were AICA ribotide (ZMP) accumulation-dependent and adenosine monophosphate-activated protein kinase (AMPK) activation-independent in CLL cells. Furthermore, AICAR induced the accumulation of NOXA protein in all CLL samples and BIM protein in about half of these samples, without modifying the levels of other BCL-2 family proteins analyzed. Importantly, AICAR induced apoptosis irrespective of the tumor suppressor TP53 and ataxia telangiectasia mutated status in CLL cells. AMPK activation with phenformin or A-769662 did not induce apoptosis in CLL cells. Finally, AICAR induced apoptosis in B lymphocytes from AMPKa1−/− mice. Taken together, our results demonstrate that AICAR induces apoptosis in B lymphocytes through the mitochondrial pathway by an AMPK- and p53-independent mechanism. Disclosures: Gil: Advancell-In Vitro Cell Technologies S.L.: Patents & Royalties, Research Funding. Campàs:Advancell-In Vitro Cell Technologies : Employment, Patents & Royalties.

scholarly journals The primary cilium dampens proliferative signaling and represses a G2/M transcriptional network in quiescent myoblasts

2019 ◽  
Author(s):  
Nisha Venugopal ◽  
Ananga Ghosh ◽  
Hardik Gala ◽  
Ajoy Aloysius ◽  
Neha Vyas ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Primary Cilium ◽  
Developmental Disorders ◽  
Adult Stem Cells ◽  
Primary Cilia ◽  
Translational Repressor ◽  
Elevated Protein ◽  
Proliferative Signaling

Abstract Background: Reversible cell cycle arrest (quiescence/G0) is characteristic of adult stem cells and is actively controlled at multiple levels. Quiescent cells also extend a primary cilium, which functions as a signaling hub. Primary cilia have been shown to be important in multiple developmental processes, and are implicated in numerous developmental disorders. Although the association of the cilium with G0 is established, the role of the cilium in the control of the quiescence program is still poorly understood.Results: Primary cilia are dynamically regulated across different states of cell cycle exit in skeletal muscle myoblasts: quiescent myoblasts elaborate a primary cilium in vivo and in vitro , but terminally differentiated myofibers do not. Myoblasts where ciliogenesis is ablated using RNAi against a key ciliary assembly protein (IFT88) can exit the cell cycle but display an altered quiescence program and impaired self-renewal. Specifically, the G0 transcriptome in IFT88 knockdown cells is aberrantly enriched for G2/M regulators, suggesting a focused repression of this network by the cilium. Cilium-ablated cells also exhibit features of activation including enhanced activity of Wnt and mitogen signaling and elevated protein synthesis via inactivation of the translational repressor 4E-BP1.Conclusions: Taken together, our results show that the primary cilium integrates and dampens proliferative signaling, represses translation and G2/M genes, and is integral to the establishment of the quiescence program.

Primary Cilia of Odontoblasts: Possible Role in Molar Morphogenesis

2009 ◽  
Vol 88 (10) ◽  
pp. 910-915 ◽  
Author(s):  
B. Thivichon-Prince ◽  
M.L. Couble ◽  
A. Giamarchi ◽  
P. Delmas ◽  
B. Franco ◽  
...  
Keyword(s):  
Primary Cilium ◽  
Close Relationships ◽  
Primary Cilia ◽  
Nerve Fibers ◽  
Vertebrate Cell ◽  
Pain Transmission ◽  
Dentin Formation

A primary cilium, a sensory organelle present in almost every vertebrate cell, is regularly described in odontoblasts, projecting from the surfaces of the cells. Based on the hypothesis that the primary cilium is crucial both for dentin formation and possibly in tooth pain transmission, we have investigated the expression and localization of the main cilium components and involvement of the OFD1 gene in tooth morphogenesis. Odontoblasts in vitro express tubulin, inversin, rootletin, OFD1, BBS4, BBS6, ALMS1, KIF3A, PC1, and PC2. In vivo, cilia are aligned parallel to the dentin walls, with the top part oriented toward the pulp core. Close relationships between cilium and nerve fibers are evidenced. Calcium channels are concentrated in the vicinity of the basal body. Analysis of these data suggests a putative role of cilia in sensing the microenvironment, probably related to dentin secretion. This hypothesis is enhanced by the huge defects observed on molars from Ofd1 knockout mice, showing undifferentiated dentin-forming cells.

scholarly journals MicroRNA-29b Regulates the Mitochondria-Dependent Apoptotic Pathway by Targeting Bax in Doxorubicin Cardiotoxicity

2018 ◽  
Vol 48 (2) ◽  
pp. 692-704 ◽  
Author(s):  
Xibo Jing ◽  
Jingxiao Yang ◽  
Lu Jiang ◽  
Jianghong Chen ◽  
Haiyan Wang
Keyword(s):  
Cardiac Function ◽  
Cardiac Fibrosis ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Therapeutic Effects ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Rat Cardiomyocytes ◽  
Myocardial Apoptosis ◽  
Mitochondrial Membrane Depolarization

Background/Aims: Myocardial apoptosis plays an important role in doxorubicin (Dox) cardiotoxicity. MicroRNA-29 (miR-29) is suggested to function as an anti-fibrotic factor with potential therapeutic effects on cardiac fibrosis. However, it has not been shown whether there is an association between miR-29b and myocardial apoptosis. Methods: Male Wistar rats were transfected with miR-29b agomir by local delivery to the myocardium prior to Dox treatment. Rat cardiomyocytes were pretreated with miR-29b mimics or inhibitor followed by Dox incubation in vitro. Cardiac function and underlying mechanisms were evaluated by echocardiography, immunofluorescence, flow cytometry, real-time PCR, and western blotting. Results: Our results revealed that miR-29b is the only member of the miR-29 family that was significantly downregulated in myocardium from Dox-treated rats. Delivery of miR-29b agomir to myocardium resulted in a marked improvement of cardiac function. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining showed that rescue of miR-29b expression inhibited Dox-induced myocardial apoptosis, concomitantly with increased Bcl-2 expression and decreased Bax expression and caspase-3 activity. In vitro, miR-29b overexpression mitigated, whereas inhibition of miR-29b promoted, Dox-induced cardiomyocyte apoptosis. Mechanistically, miR-29b negatively regulated Bax expression by directly targeting the 3′ untranslated region of Bax. In Dox-treated cardiomyocytes, upregulation of miR-29b resulted in a significant decrease in Bax expression, with an increase in Bcl-2 expression, accompanied by inhibition of mitochondrial membrane depolarization, cytochrome c release, and caspase activation. However, inhibition of miR-29b produced the opposite effects by further augmenting the effects of Dox. Conclusions: These data demonstrate that miR-29b prevents Dox-induced myocardial apoptosis through inhibition of the mitochondria-dependent pathway by directly targeting Bax, suggesting that miR-29b is a potential novel therapeutic target for the treatment of Dox cardiotoxicity.

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