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Muhamad NA, Masutani K, Furukawa S, Yuri S, Toriyama M, Matsumoto C, Itoh S, Shinagawa Y, Isotani A, Toriyama M, Itoh H. Astrocyte-Specific Inhibition of the Primary Cilium Suppresses C3 Expression in Reactive Astrocyte. Cell Mol Neurobiol 2024; 44:48. [PMID: 38822888 PMCID: PMC11144130 DOI: 10.1007/s10571-024-01482-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 05/21/2024] [Indexed: 06/03/2024]
Abstract
C3-positive reactive astrocytes play a neurotoxic role in various neurodegenerative diseases. However, the mechanisms controlling C3-positive reactive astrocyte induction are largely unknown. We found that the length of the primary cilium, a cellular organelle that receives extracellular signals was increased in C3-positive reactive astrocytes, and the loss or shortening of primary cilium decreased the count of C3-positive reactive astrocytes. Pharmacological experiments suggested that Ca2+ signalling may synergistically promote C3 expression in reactive astrocytes. Conditional knockout (cKO) mice that specifically inhibit primary cilium formation in astrocytes upon drug stimulation exhibited a reduction in the proportions of C3-positive reactive astrocytes and apoptotic cells in the brain even after the injection of lipopolysaccharide (LPS). Additionally, the novel object recognition (NOR) score observed in the cKO mice was higher than that observed in the neuroinflammation model mice. These results suggest that the primary cilium in astrocytes positively regulates C3 expression. We propose that regulating astrocyte-specific primary cilium signalling may be a novel strategy for the suppression of neuroinflammation.
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Affiliation(s)
- Nor Atiqah Muhamad
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan
| | - Kohei Masutani
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan
| | - Shota Furukawa
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan
| | - Shunsuke Yuri
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan
| | - Michinori Toriyama
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University, 1 Gakuenuegahara, Sanda, Hyogo, 669-1330, Japan
| | - Chuya Matsumoto
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan
| | - Seiya Itoh
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan
| | - Yuichiro Shinagawa
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan
| | - Ayako Isotani
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan
| | - Manami Toriyama
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan.
| | - Hiroshi Itoh
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama Cho, Ikoma, Nara, 630-0192, Japan.
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Segarra-Queralt M, Crump K, Pascuet-Fontanet A, Gantenbein B, Noailly J. The interplay between biochemical mediators and mechanotransduction in chondrocytes: Unravelling the differential responses in primary knee osteoarthritis. Phys Life Rev 2024; 48:205-221. [PMID: 38377727 DOI: 10.1016/j.plrev.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/22/2024]
Abstract
In primary or idiopathic osteoarthritis (OA), it is unclear which factors trigger the shift of articular chondrocyte activity from pro-anabolic to pro-catabolic. In fact, there is a controversy about the aetiology of primary OA, either mechanical or inflammatory. Chondrocytes are mechanosensitive cells, that integrate mechanical stimuli into cellular responses in a process known as mechanotransduction. Mechanotransduction occurs thanks to the activation of mechanosensors, a set of specialized proteins that convert physical cues into intracellular signalling cascades. Moderate levels of mechanical loads maintain normal tissue function and have anti-inflammatory effects. In contrast, mechanical over- or under-loading might lead to cartilage destruction and increased expression of pro-inflammatory cytokines. Simultaneously, mechanotransduction processes can regulate and be regulated by pro- and anti-inflammatory soluble mediators, both local (cells of the same joint, i.e., the chondrocytes themselves, infiltrating macrophages, fibroblasts or osteoclasts) and systemic (from other tissues, e.g., adipokines). Thus, the complex process of mechanotransduction might be altered in OA, so that cartilage-preserving chondrocytes adopt a different sensitivity to mechanical signals, and mechanic stimuli positively transduced in the healthy cartilage may become deleterious under OA conditions. This review aims to provide an overview of how the biochemical exposome of chondrocytes can alter important mechanotransduction processes in these cells. Four principal mechanosensors, i.e., integrins, Ca2+ channels, primary cilium and Wnt signalling (canonical and non-canonical) were targeted. For each of these mechanosensors, a brief summary of the response to mechanical loads under healthy or OA conditions is followed by a concise overview of published works that focus on the further regulation of the mechanotransduction pathways by biochemical factors. In conclusion, this paper discusses and explores how biological mediators influence the differential behaviour of chondrocytes under mechanical loads in healthy and primary OA.
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Affiliation(s)
- Maria Segarra-Queralt
- BCN MedTech, Universitat Pompeu Fabra, C/ de la Mercè, 12, Barcelona, 08002, Catalonia, Spain
| | - Katherine Crump
- Tissue Engineering for Orthopaedics & Mechanobiology, Bone & Joint Program, Department for BioMedical Research (DBMR), Medical Faculty, University of Bern, Murtenstrasse 35, Bern, 3008, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences (GCB), University of Bern, Mittelstrasse 43, Bern, 3012, Bern, Switzerland
| | - Andreu Pascuet-Fontanet
- BCN MedTech, Universitat Pompeu Fabra, C/ de la Mercè, 12, Barcelona, 08002, Catalonia, Spain
| | - Benjamin Gantenbein
- Tissue Engineering for Orthopaedics & Mechanobiology, Bone & Joint Program, Department for BioMedical Research (DBMR), Medical Faculty, University of Bern, Murtenstrasse 35, Bern, 3008, Bern, Switzerland; Department of Orthopedic Surgery & Traumatology, Inselspital, University of Bern, Freiburgstrasse 18, Bern, 3010, Bern, Switzerland
| | - Jérôme Noailly
- BCN MedTech, Universitat Pompeu Fabra, C/ de la Mercè, 12, Barcelona, 08002, Catalonia, Spain.
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Guan YT, Zhang C, Zhang HY, Wei WL, Yue W, Zhao W, Zhang DH. Primary cilia: Structure, dynamics, and roles in cancer cells and tumor microenvironment. J Cell Physiol 2023; 238:1788-1807. [PMID: 37565630 DOI: 10.1002/jcp.31092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/24/2023] [Accepted: 07/13/2023] [Indexed: 08/12/2023]
Abstract
Despite the initiation of tumor arises from tumorigenic transformation signaling in cancer cells, cancer cell survival, invasion, and metastasis also require a dynamic and reciprocal association with extracellular signaling from tumor microenvironment (TME). Primary cilia are the antenna-like structure that mediate signaling sensation and transduction in different tissues and cells. Recent studies have started to uncover that the heterogeneous ciliation in cancer cells and cells from the TME in tumor growth impels asymmetric paracellular signaling in the TME, indicating the essential functions of primary cilia in homeostasis maintenance of both cancer cells and the TME. In this review, we discussed recent advances in the structure and assembly of primary cilia, and the role of primary cilia in tumor and TME formation, as well as the therapeutic potentials that target ciliary dynamics and signaling from the cells in different tumors and the TME.
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Affiliation(s)
- Yi-Ting Guan
- Zhanjiang Institute of Clinical Medicine, Central People's Hospital of Zhanjiang, Guangdong Medical University Zhanjiang Central Hospital, Zhanjiang, P. R. China
| | - Chong Zhang
- Zhanjiang Institute of Clinical Medicine, Central People's Hospital of Zhanjiang, Guangdong Medical University Zhanjiang Central Hospital, Zhanjiang, P. R. China
| | - Hong-Yong Zhang
- Zhanjiang Institute of Clinical Medicine, Central People's Hospital of Zhanjiang, Guangdong Medical University Zhanjiang Central Hospital, Zhanjiang, P. R. China
| | - Wen-Lu Wei
- Zhanjiang Institute of Clinical Medicine, Central People's Hospital of Zhanjiang, Guangdong Medical University Zhanjiang Central Hospital, Zhanjiang, P. R. China
| | - Wei Yue
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Wei Zhao
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, P. R. China
- Department of Posthodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, P. R. China
| | - Dong-Hui Zhang
- Zhanjiang Institute of Clinical Medicine, Central People's Hospital of Zhanjiang, Guangdong Medical University Zhanjiang Central Hospital, Zhanjiang, P. R. China
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Leu T, Denda J, Wrobeln A, Fandrey J. Hypoxia-Inducible Factor-2alpha Affects the MEK/ERK Signaling Pathway via Primary Cilia in Connection with the Intraflagellar Transport Protein 88 Homolog. Mol Cell Biol 2023; 43:174-183. [PMID: 37074220 PMCID: PMC10153011 DOI: 10.1080/10985549.2023.2198931] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/25/2023] [Indexed: 04/20/2023] Open
Abstract
The ability of cells to communicate with their surrounding is a prerequisite for essential processes such as proliferation, apoptosis, migration, and differentiation. To this purpose, primary cilia serve as antennae-like structures on the surface of most mammalian cell types. Cilia allow signaling via hedgehog, Wnt or TGF-beta pathways. Their length, in part controlled by the activity of intraflagellar transport (IFT), is a parameter for adequate function of primary cilia. Here we show, in murine neuronal cells, that intraflagellar transport protein 88 homolog (IFT88) directly interacts with the hypoxia-inducible factor-2α (HIF-2α), hitherto known as an oxygen-regulated transcription factor. Furthermore, HIF-2α accumulates in the ciliary axoneme and promotes ciliary elongation under hypoxia. Loss of HIF-2α affected ciliary signaling in neuronal cells by decreasing transcription of Mek1/2 and Erk1/2. Targets of the MEK/ERK signaling pathway, such as Fos and Jun, were significantly decreased. Our results suggest that HIF-2α influences ciliary signaling by interacting with IFT88 under hypoxic conditions. This implies an unexpected and far more extensive function of HIF-2α than described before.
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Affiliation(s)
- Tristan Leu
- Institute of Physiology, University Duisburg-Essen, Essen, Germany
| | - Jannik Denda
- Institute of Physiology, University Duisburg-Essen, Essen, Germany
| | - Anna Wrobeln
- Institute of Physiology, University Duisburg-Essen, Essen, Germany
| | - Joachim Fandrey
- Institute of Physiology, University Duisburg-Essen, Essen, Germany
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Lee JW, Cho JY, Thuy PX, Moon EY. HeLa Cervical Cancer Cells Are Maintained by Nephronophthisis 3-Associated Primary Cilium Formation via ROS-Induced ERK and HIF-1α Activation under Serum-Deprived Normoxic Condition. Int J Mol Sci 2022; 23:ijms232314500. [PMID: 36498831 PMCID: PMC9739938 DOI: 10.3390/ijms232314500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/28/2022] [Accepted: 11/03/2022] [Indexed: 11/23/2022] Open
Abstract
The primary cilium (PC) is a microtubule-based antenna-like organelle projecting from the surface of the cell membrane. We previously reported that PC formation could be regulated by nephronophthisis 3 (NPHP3) expression followed by its interaction with thymosin β4. Here, we investigated whether cancer cell viability is regulated by NPHP3-mediated PC formation. The total and viable cell number were reduced by incubating cells under serum deprivation (SD) without fetal bovine serum (-FBS). PC frequency was increased by SD which enhanced NPHP3 expression and hypoxia inducible factor (HIF)-1α. The role of HIF-1α on NPHP3 expression and PC formation was confirmed by the binding of HIF-1α to the NPHP3 promoter and siRNA-based inhibition of HIF-1α (siHIF-1α), respectively. HIF-1α-stabilizing dimethyloxallyl glycine (DMOG) and hypoxic conditions increased NPHP3 expression and PC formation. In addition, as SD elevated the reactive oxygen species (ROS), PC frequency and NPHP3 expression were inhibited by a treatment with N-acetylcysteine (NAC), a ROS scavenger. PC formation was increased by H2O2 treatment, which was inhibited by siHIF-1α. The inhibition of ERK with P98059 decreased the frequency of PC formation and NPHP3 expression. Cell viability was reduced by a treatment with ciliobrevin A (CilioA) to inhibit PC formation, which was re-affirmed by using PC-deficient IFT88-/- cells. Taken together, the results imply that PC formation in cancer cells could be controlled by NPHP3 expression through ROS-induced HIF-1α and ERK activation under SD conditions. It suggests that cancer cell viability under SD conditions could be maintained by NPHP3 expression to regulate PC formation.
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Affiliation(s)
| | | | | | - Eun-Yi Moon
- Correspondence: ; Tel.: +82-2-3408-3768; Fax: +82-2-3408-4334
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Primary Cilia: A Cellular Regulator of Articular Cartilage Degeneration. Stem Cells Int 2022; 2022:2560441. [PMID: 36193252 PMCID: PMC9525753 DOI: 10.1155/2022/2560441] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/29/2022] [Accepted: 09/02/2022] [Indexed: 11/18/2022] Open
Abstract
Osteoarthritis (OA) is the most common joint disease that can cause pain and disability in adults. The main pathological characteristic of OA is cartilage degeneration, which is caused by chondrocyte apoptosis, cartilage matrix degradation, and inflammatory factor destruction. The current treatment for patients with OA focuses on delaying its progression, such as oral anti-inflammatory analgesics or injection of sodium gluconate into the joint cavity. Primary cilia are an important structure involved in cellular signal transduction. Thus, they are very sensitive to mechanical and physicochemical stimuli. It is reported that the primary cilia may play an important role in the development of OA. Here, we review the correlation between the morphology (location, length, incidence, and orientation) of chondrocyte primary cilia and OA and summarize the relevant signaling pathways in chondrocytes that could regulate the OA process through primary cilia, including Hedgehog, Wnt, and inflammation-related signaling pathways. These data provide new ideas for OA treatment.
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7
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Qiao Y, Wang Z, Bunikyte R, Chen X, Jin S, Qi X, Cai D, Feng S. Cobalt chloride-simulated hypoxia elongates primary cilia in immortalized human retina pigment epithelial-1 cells. Biochem Biophys Res Commun 2021; 555:190-195. [PMID: 33823365 DOI: 10.1016/j.bbrc.2021.03.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 11/20/2022]
Abstract
Primary cilia are microtubule-based organelles that are involved in sensing micro-environmental cues and regulating cellular homeostasis via triggering signaling cascades. Hypoxia is one of the most common environmental stresses that organ and tissue cells may often encounter during embryogenesis, cell differentiation, infection, inflammation, injury, cerebral and cardiac ischemia, or tumorigenesis. Although hypoxia has been reported to promote or inhibit primary ciliogenesis in different tissues or cultured cell lines, the role of hypoxia in ciliogenesis is controversial and still unclear. Here we investigated the primary cilia change under cobalt chloride (CoCl2)-simulated hypoxia in immortalized human retina pigment epithelial-1 (hTERT RPE-1) cells. We found CoCl2 treatment elongated primary cilia in a time- and dose-dependent manner. The prolonged cilia recovered back to near normal length when CoCl2 was washed out from the cell culture medium. Under CoCl2-simulated hypoxia, the protein expression levels of HIF-1/2α and acetylated-α-tubulin (cilia marker) were increased, while the protein expression level of Rabaptin-5 is decreased during hypoxia. Taken together, our results suggest that hypoxia may elongate primary cilia by downregulating Rabaptin-5 involved endocytosis. The coordination between endocytosis and ciliogenesis may be utilized by cells to adapt to hypoxia.
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Affiliation(s)
- Ying Qiao
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Zhengduo Wang
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Raimonda Bunikyte
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Xi Chen
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Shuang Jin
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Xufeng Qi
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Dongqing Cai
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China.
| | - Shanshan Feng
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China.
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Toriyama M, Ishii KJ. Primary Cilia in the Skin: Functions in Immunity and Therapeutic Potential. Front Cell Dev Biol 2021; 9:621318. [PMID: 33644059 PMCID: PMC7905053 DOI: 10.3389/fcell.2021.621318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/04/2021] [Indexed: 12/21/2022] Open
Abstract
The skin is the biggest organ and provides a physical and immunological barrier against pathogen infection. The distribution of primary cilia in the skin of mice has been reported, but which cells in human skin have them has not, and we still know very little about how they change in response to immune reactions or disease. This review introduces several studies that describe mechanisms of cilia regulation by immune reaction and the physiological relevance of cilia regulating proliferation and differentiation of stroma cells, including skin-resident Langerhans cells. We discuss the possibility of primary cilia pathology in allergic atopic dermatitis and the potential for therapies targeting primary cilia signaling.
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Affiliation(s)
- Manami Toriyama
- Graduate School of Pharmacological Sciences, Osaka University, Osaka, Japan.,Center for Vaccine and Adjuvant Research, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan.,Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Ken J Ishii
- Center for Vaccine and Adjuvant Research, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan.,Laboratory of Vaccine Science, World Premier International Research Center Initiative (WPI) Immunology Frontier Research Center, Osaka University, Osaka, Japan.,Division of Vaccine Science, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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9
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Ding L, Sontz EA, Saqui-Salces M, Merchant JL. Interleukin-1β Suppresses Gastrin via Primary Cilia and Induces Antral Hyperplasia. Cell Mol Gastroenterol Hepatol 2021; 11:1251-1266. [PMID: 33347972 PMCID: PMC8005816 DOI: 10.1016/j.jcmgh.2020.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 01/02/2023]
Abstract
BACKGROUND & AIMS Helicobacter pylori infection in humans typically begins with colonization of the gastric antrum. The initial Th1 response occasionally coincides with an increase in gastrin secretion. Subsequently, the gastritis segues to chronic atrophic gastritis, metaplasia, dysplasia and distal gastric cancer. Despite these well characterized clinical events, the link between inflammatory cytokines and non-cardia gastric cancer remains difficult to study in mouse models. Prior studies have demonstrated that overexpression of the Hedgehog (HH) effector GLI2 induces loss of gastrin (atrophy) and antral hyperplasia. To determine the link between specific cytokines, HH signaling and pre-neoplastic changes in the gastric antrum. METHODS Mouse lines were created to conditionally direct IL1β or IFN-γ to the antrum using the Gastrin-CreERT2 and Tet activator. Primary cilia, which transduces HH signaling, on G cells were disrupted by deleting the ciliary motor protein KIF3a. Phenotypic changes were assessed by histology and western blots. A subclone of GLUTag enteroendocrine cells selected for gastrin expression and the presence of primary cilia was treated with recombinant SHH, IL1β or IFN-γ with or without kif3a siRNA. RESULTS IFN-γ increased gastrin and induced antral hyperplasia. However, antral expression of IL1β suppressed tissue and serum gastrin, while also inducing antral hyperplasia. IFN-γ treatment of GLUTAg cells suppressed GLI2 and induced gastrin, without affecting cilia length. By contrast, IL1β treatment doubled primary cilia length, induced GLI2 and suppressed gastrin gene expression. Knocking down kif3a in GLUTAg cells mitigated SHH or IL1β suppression of gastrin. CONCLUSIONS Overexpression of IL1β in the antrum was sufficient to induce antral hyperplasia coincident with suppression of gastrin via primary cilia. ORCID: #0000-0002-6559-8184.
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Affiliation(s)
- Lin Ding
- Department of Internal Medicine-Gastroenterology, University of Michigan, Ann Arbor, Michigan; Department of Medicine-Gastroenterology, University of Arizona, Tucson, Arizona
| | - Erica A Sontz
- Department of Medicine-Gastroenterology, University of Arizona, Tucson, Arizona
| | | | - Juanita L Merchant
- Department of Internal Medicine-Gastroenterology, University of Michigan, Ann Arbor, Michigan; Department of Medicine-Gastroenterology, University of Arizona, Tucson, Arizona.
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Fu S, Meng H, Inamdar S, Das B, Gupta H, Wang W, Thompson CL, Knight MM. Activation of TRPV4 by mechanical, osmotic or pharmaceutical stimulation is anti-inflammatory blocking IL-1β mediated articular cartilage matrix destruction. Osteoarthritis Cartilage 2021; 29:89-99. [PMID: 33395574 PMCID: PMC7799379 DOI: 10.1016/j.joca.2020.08.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 08/04/2020] [Accepted: 08/11/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Cartilage health is maintained in response to a range of mechanical stimuli including compressive, shear and tensile strains and associated alterations in osmolality. The osmotic-sensitive ion channel Transient Receptor Potential Vanilloid 4 (TRPV4) is required for mechanotransduction. Mechanical stimuli inhibit interleukin-1β (IL-1β) mediated inflammatory signalling, however the mechanism is unclear. This study aims to clarify the role of TRPV4 in this response. DESIGN TRPV4 activity was modulated glycogen synthase kinase (GSK205 antagonist or GSK1016790 A (GSK101) agonist) in articular chondrocytes and cartilage explants in the presence or absence of IL-1β, mechanical (10% cyclic tensile strain (CTS), 0.33 Hz, 24hrs) or osmotic loading (200mOsm, 24hrs). Nitric oxide (NO), prostaglandin E2 (PGE2) and sulphated glycosaminoglycan (sGAG) release and cartilage biomechanics were analysed. Alterations in post-translational tubulin modifications and primary cilia length regulation were examined. RESULTS In isolated chondrocytes, mechanical loading inhibited IL-1β mediated NO and PGE2 release. This response was inhibited by GSK205. Similarly, osmotic loading was anti-inflammatory in cells and explants, this response was abrogated by TRPV4 inhibition. In explants, GSK101 inhibited IL-1β mediated NO release and prevented cartilage degradation and loss of mechanical properties. Upon activation, TRPV4 cilia localisation was increased resulting in histone deacetylase 6 (HDAC6)-dependent modulation of soluble tubulin and altered cilia length regulation. CONCLUSION Mechanical, osmotic or pharmaceutical activation of TRPV4 regulates HDAC6-dependent modulation of ciliary tubulin and is anti-inflammatory. This study reveals for the first time, the potential of TRPV4 manipulation as a novel therapeutic mechanism to supress pro-inflammatory signalling and cartilage degradation.
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Affiliation(s)
- S Fu
- Centre for Predictive In Vitro Models, School of Engineering and Materials Science, Queen Mary University of London, UK.
| | - H Meng
- Centre for Predictive In Vitro Models, School of Engineering and Materials Science, Queen Mary University of London, UK.
| | - S Inamdar
- Centre for Predictive In Vitro Models, School of Engineering and Materials Science, Queen Mary University of London, UK.
| | - B Das
- Centre for Predictive In Vitro Models, School of Engineering and Materials Science, Queen Mary University of London, UK
| | - H Gupta
- Centre for Predictive In Vitro Models, School of Engineering and Materials Science, Queen Mary University of London, UK.
| | - W Wang
- Centre for Predictive In Vitro Models, School of Engineering and Materials Science, Queen Mary University of London, UK.
| | - C L Thompson
- Centre for Predictive In Vitro Models, School of Engineering and Materials Science, Queen Mary University of London, UK.
| | - M M Knight
- Centre for Predictive In Vitro Models, School of Engineering and Materials Science, Queen Mary University of London, UK.
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11
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Sub-toxic levels of Co 2+ are anti-inflammatory and protect cartilage from degradation caused by IL-1β. Clin Biomech (Bristol, Avon) 2020; 79:104924. [PMID: 31928794 DOI: 10.1016/j.clinbiomech.2019.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 11/23/2019] [Accepted: 12/10/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Cobalt ions from some orthopaedic implants induce a dose-dependent cytotoxic and pro-inflammatory response. Recent studies show that sub-toxic levels of cobalt influence actin organisation regulating fibroblasts and macrophages behaviour. However little is known about the influence of sub-toxic levels of cobalt on articular cartilage biology and biomechanics. Previously, we have reported that IL-1β signalling in chondrocytes, is regulated by primary cilia and associated intraflagellar transport. Since primary cilia expression is modulated by actin organisation, we set out to test the hypothesis that sub-toxic levels of cobalt regulate cilia expression and IL-1β signalling thereby influencing articular cartilage degradation. METHODS Isolated chondrocytes and bovine cartilage explants were subjected to Co2+ in the presence and absence of IL-1β. Primary cilia were monitored by confocal immunofluorescence. Nitric oxide and PGE2 release were used to monitor IL-1β signalling. Degradation of cartilage matrix was assessed by the release of sGAG and the biomechanical properties of the tissue in uniaxial unconfined compression. FINDINGS Sub-toxic levels of Co2+ (50 μM) blocked IL-1β-induced primary cilia elongation in isolated chondrocytes. This was associated with disruption of pro-inflammatory signalling in both isolated chondrocytes and cartilage explants, and inhibition of cartilage matrix degradation and loss of biomechanical properties. INTERPRETATION This study reveals that low levels of cobalt ions are anti-inflammatory, preventing cartilage degradation in response to IL-1β. This mechanism is associated with regulation of primary cilia elongation. These observations provide new insight into the potential beneficial role of cobalt and may lead to novel mechanisms for controlling cartilage inflammation.
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12
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Mc Fie M, Koneva L, Collins I, Coveney CR, Clube AM, Chanalaris A, Vincent TL, Bezbradica JS, Sansom SN, Wann AKT. Ciliary proteins specify the cell inflammatory response by tuning NFκB signalling, independently of primary cilia. J Cell Sci 2020; 133:jcs.239871. [PMID: 32503942 PMCID: PMC7358134 DOI: 10.1242/jcs.239871] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 05/21/2020] [Indexed: 12/17/2022] Open
Abstract
Complex inflammatory signalling cascades define the response to tissue injury but also control development and homeostasis, limiting the potential for these pathways to be targeted therapeutically. Primary cilia are subcellular regulators of cellular signalling, controlling how signalling is organized, encoded and, in some instances, driving or influencing pathogenesis. Our previous research revealed that disruption of ciliary intraflagellar transport (IFT), altered the cell response to IL-1β, supporting a putative link emerging between cilia and inflammation. Here, we show that IFT88 depletion affects specific cytokine-regulated behaviours, changing cytosolic NFκB translocation dynamics but leaving MAPK signalling unaffected. RNA-seq analysis indicates that IFT88 regulates one third of the genome-wide targets, including the pro-inflammatory genes Nos2, Il6 and Tnf. Through microscopy, we find altered NFκB dynamics are independent of assembly of a ciliary axoneme. Indeed, depletion of IFT88 inhibits inflammatory responses in the non-ciliated macrophage. We propose that ciliary proteins, including IFT88, KIF3A, TTBK2 and NPHP4, act outside of the ciliary axoneme to tune cytoplasmic NFκB signalling and specify the downstream cell response. This is thus a non-canonical function for ciliary proteins in shaping cellular inflammation. This article has an associated First Person interview with the first author of the paper. Summary: Ciliary proteins, acting independently of the ciliary axoneme, regulate the dynamics of cytosolic NFκB, but not other signalling pathways, defining an important subset of the inflammatory response.
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Affiliation(s)
- Megan Mc Fie
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK.,School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Lada Koneva
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
| | - Isabella Collins
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
| | - Clarissa R Coveney
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
| | - Aisling M Clube
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
| | - Anastasios Chanalaris
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
| | - Tonia L Vincent
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
| | - Jelena S Bezbradica
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
| | - Stephen N Sansom
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
| | - Angus K T Wann
- Kennedy Institute of Rheumatology Research, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Medical Sciences Division, University of Oxford, Oxford OX3 7FY, UK
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13
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Tao F, Jiang T, Tao H, Cao H, Xiang W. Primary cilia: Versatile regulator in cartilage development. Cell Prolif 2020; 53:e12765. [PMID: 32034931 PMCID: PMC7106963 DOI: 10.1111/cpr.12765] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/21/2019] [Accepted: 12/29/2019] [Indexed: 02/07/2023] Open
Abstract
Cartilage is a connective tissue in the skeletal system and has limited regeneration ability and unique biomechanical reactivity. The growth and development of cartilage can be affected by different physical, chemical and biological factors, such as mechanical stress, inflammation, osmotic pressure, hypoxia and signalling transduction. Primary cilia are multifunctional sensory organelles that regulate diverse signalling transduction and cell activities. They are crucial for the regulation of cartilage development and act in a variety of ways, such as react to mechanical stress, mediate signalling transduction, regulate cartilage‐related diseases progression and affect cartilage tumorigenesis. Therefore, research on primary cilia‐mediated cartilage growth and development is currently extremely popular. This review outlines the role of primary cilia in cartilage development in recent years and elaborates on the potential regulatory mechanisms from different aspects.
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Affiliation(s)
- Fenghua Tao
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Ting Jiang
- Department of Neurological Rehabilitation, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Hai Tao
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Hui Cao
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Wei Xiang
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
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14
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O’Toole SM, Watson DS, Novoselova TV, Romano LEL, King PJ, Bradshaw TY, Thompson CL, Knight MM, Sharp TV, Barnes MR, Srirangalingam U, Drake WM, Chapple JP. Oncometabolite induced primary cilia loss in pheochromocytoma. Endocr Relat Cancer 2019; 26:165-180. [PMID: 30345732 PMCID: PMC6215910 DOI: 10.1530/erc-18-0134] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 09/05/2018] [Indexed: 12/24/2022]
Abstract
Primary cilia are sensory organelles involved in regulation of cellular signaling. Cilia loss is frequently observed in tumors; yet, the responsible mechanisms and consequences for tumorigenesis remain unclear. We demonstrate that cilia structure and function is disrupted in human pheochromocytomas - endocrine tumors of the adrenal medulla. This is concomitant with transcriptional changes within cilia-mediated signaling pathways that are associated with tumorigenesis generally and pheochromocytomas specifically. Importantly, cilia loss was most dramatic in patients with germline mutations in the pseudohypoxia-linked genes SDHx and VHL. Using a pheochromocytoma cell line derived from rat, we show that hypoxia and oncometabolite-induced pseudohypoxia are key drivers of cilia loss and identify that this is dependent on activation of an Aurora-A/HDAC6 cilia resorption pathway. We also show cilia loss drives dramatic transcriptional changes associated with proliferation and tumorigenesis. Our data provide evidence for primary cilia dysfunction contributing to pathogenesis of pheochromocytoma by a hypoxic/pseudohypoxic mechanism and implicates oncometabolites as ciliary regulators. This is important as pheochromocytomas can cause mortality by mechanisms including catecholamine production and malignant transformation, while hypoxia is a general feature of solid tumors. Moreover, pseudohypoxia-induced cilia resorption can be pharmacologically inhibited, suggesting potential for therapeutic intervention.
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Affiliation(s)
- Samuel M O’Toole
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
- Department of EndocrinologySt Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
| | - David S Watson
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
| | - Tatiana V Novoselova
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
| | - Lisa E L Romano
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
| | - Peter J King
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
| | - Teisha Y Bradshaw
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
| | - Clare L Thompson
- Institute of Bioengineering and School of Engineering and Material SciencesQueen Mary University of London, London, UK
| | - Martin M Knight
- Institute of Bioengineering and School of Engineering and Material SciencesQueen Mary University of London, London, UK
| | - Tyson V Sharp
- Barts Cancer InstituteQueen Mary University of London, London, UK
| | - Michael R Barnes
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
| | - Umasuthan Srirangalingam
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
- Department of EndocrinologySt Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
- Department of Diabetes and EndocrinologyUniversity College London Hospital, London, UK
| | - William M Drake
- Department of EndocrinologySt Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
| | - J Paul Chapple
- William Harvey Research InstituteBarts and the London School of Medicine, Queen Mary University of London, London, UK
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15
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Coveney CR, Collins I, Mc Fie M, Chanalaris A, Yamamoto K, Wann AKT. Cilia protein IFT88 regulates extracellular protease activity by optimizing LRP-1-mediated endocytosis. FASEB J 2018; 32:fj201800334. [PMID: 29920219 PMCID: PMC6219823 DOI: 10.1096/fj.201800334] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 06/04/2018] [Indexed: 01/15/2023]
Abstract
Matrix protease activity is fundamental to developmental tissue patterning and remains influential in adult homeostasis. In cartilage, the principal matrix proteoglycan is aggrecan, the protease-mediated catabolism of which defines arthritis; however, the pathophysiologic mechanisms that drive aberrant aggrecanolytic activity remain unclear. Human ciliopathies exhibit altered matrix, which has been proposed to be the result of dysregulated hedgehog signaling that is tuned within the primary cilium. Here, we report that disruption of intraflagellar transport protein 88 (IFT88), a core ciliary trafficking protein, increases chondrocyte aggrecanase activity in vitro. We find that the receptor for protease endocytosis in chondrocytes, LDL receptor-related protein 1 (LRP-1), is unevenly distributed over the cell membrane, often concentrated at the site of cilia assembly. Hypomorphic mutation of IFT88 disturbs this apparent hot spot for protease uptake, increases receptor shedding, and results in a reduced rate of protease clearance from the extracellular space. We propose that IFT88 and/or the cilium regulates the extracellular remodeling of matrix-independently of Hedgehog regulation-by enabling rapid LRP-1-mediated endocytosis of proteases, potentially by supporting the creation of a ciliary pocket. This result highlights new roles for the cilium's machinery in matrix turnover and LRP-1 function, with potential relevance in a range of diseases.-Coveney, C. R., Collins, I., Mc Fie, M., Chanalaris, A., Yamamoto, K., Wann, A. K. T. Cilia protein IFT88 regulates extracellular protease activity by optimizing LRP-1-mediated endocytosis.
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Affiliation(s)
- Clarissa R. Coveney
- Arthritis Research UK Centre for Osteoarthritis Pathogenesis, Kennedy Institute, Nuffield Department for Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Isabella Collins
- Arthritis Research UK Centre for Osteoarthritis Pathogenesis, Kennedy Institute, Nuffield Department for Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Megan Mc Fie
- Arthritis Research UK Centre for Osteoarthritis Pathogenesis, Kennedy Institute, Nuffield Department for Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Anastasios Chanalaris
- Arthritis Research UK Centre for Osteoarthritis Pathogenesis, Kennedy Institute, Nuffield Department for Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Kazuhiro Yamamoto
- Arthritis Research UK Centre for Osteoarthritis Pathogenesis, Kennedy Institute, Nuffield Department for Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Angus K. T. Wann
- Arthritis Research UK Centre for Osteoarthritis Pathogenesis, Kennedy Institute, Nuffield Department for Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
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16
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Hwang HS, Park SJ, Lee MH, Kim HA. MicroRNA-365 regulates IL-1β-induced catabolic factor expression by targeting HIF-2α in primary chondrocytes. Sci Rep 2017; 7:17889. [PMID: 29263346 PMCID: PMC5738378 DOI: 10.1038/s41598-017-18059-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 12/05/2017] [Indexed: 12/27/2022] Open
Abstract
Endothelial Per-Arnt-Sim domain protein-1/hypoxia-inducible factor-2α (EPAS-1/ HIF-2α) is a catabolic transcription factor that regulates osteoarthritis (OA)-related cartilage destruction. Here, we examined whether microRNA-365 (miR-365) affects interleukin (IL)-1β-induced expression of catabolic factors in chondrocytes via regulation of HIF-2α. MiR-365 levels were significantly decreased in human OA cartilage relative to normal cartilage. Overexpression of miR-365 significantly suppressed IL-1β-induced expression of HIF-2α in human articular chondrocytes. Pharmacological inhibition of various IL-1β-associated signaling pathways revealed mitogen-activated protein kinase and nuclear factor-κB as the primary pathways driving IL-1β-mediated decreases in miR-365 and subsequent increase in HIF-2α expression. Using a luciferase reporter assay encoding the 3′ untranslated region (UTR) of human HIF-2α mRNA, we showed that overexpression of miR-365 significantly suppressed IL-1β-induced up-regulation of HIF-2α. AGO2 RNA-immunoprecipitation (IP) assay demonstrated that miR-365 and HIF-2α mRNA were enriched in the AGO2-IP fraction in miR-365-transfected primary chondrocytes compared to miR-con-transfected cells, indicating that HIF-2α is a target of miR-365. Furthermore, miR-365 overexpression significantly suppressed IL-1β-induced expression of catabolic factors, including cyclooxygenase-2 and matrix metalloproteinase-1, -3 and -13, in chondrocytes. In pellet culture of primary chondrocytes miR-365 prevented IL-1β-stimulated extracellular matrix loss and matrix metalloproteinase-13 expression. MiR-365 regulates IL-1β-stimulated catabolic effects in human chondrocytes by modulating HIF-2α expression.
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Affiliation(s)
- Hyun Sook Hwang
- Division of rheumatology, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Kyunggi, 431-070, Korea.,Institute for Skeletal Aging, Hallym University, Chunchon, 200-702, Korea
| | - Su Jin Park
- Division of rheumatology, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Kyunggi, 431-070, Korea.,Institute for Skeletal Aging, Hallym University, Chunchon, 200-702, Korea
| | - Mi Hyun Lee
- Division of rheumatology, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Kyunggi, 431-070, Korea. .,Institute for Skeletal Aging, Hallym University, Chunchon, 200-702, Korea.
| | - Hyun Ah Kim
- Division of rheumatology, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Kyunggi, 431-070, Korea. .,Institute for Skeletal Aging, Hallym University, Chunchon, 200-702, Korea.
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17
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Baek H, Shin HJ, Kim JJ, Shin N, Kim S, Yi MH, Zhang E, Hong J, Kang JW, Kim Y, Kim CS, Kim DW. Primary cilia modulate TLR4-mediated inflammatory responses in hippocampal neurons. J Neuroinflammation 2017; 14:189. [PMID: 28927423 PMCID: PMC5606072 DOI: 10.1186/s12974-017-0958-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 09/03/2017] [Indexed: 12/15/2022] Open
Abstract
Background The primary cilium is an organelle that can act as a master regulator of cellular signaling. Despite the presence of primary cilia in hippocampal neurons, their function is not fully understood. Recent studies have demonstrated that the primary cilium influences interleukin (IL)-1β-induced NF-κB signaling, ultimately mediating the inflammatory response. We, therefore, investigated ciliary function and NF-κB signaling in lipopolysaccharide (LPS)-induced neuroinflammation in conjunction with ciliary length analysis. Methods Since TLR4/NF-κB signaling is a well-known inflammatory pathway, we measured ciliary length and inflammatory mediators in wild type (WT) and TLR4−/− mice injected with LPS. Next, to exclude the effects of microglial TLR4, we examined the ciliary length, ciliary components, inflammatory cytokine, and mediators in HT22 hippocampal neuronal cells. Results Primary ciliary length decreased in hippocampal pyramidal neurons after intracerebroventricular injection of LPS in WT mice, whereas it increased in TLR4−/− mice. LPS treatment decreased primary ciliary length, activated NF-κB signaling, and increased Cox2 and iNOS levels in HT22 hippocampal neurons. In contrast, silencing Kif3a, a key protein component of cilia, increased ARL13B ciliary protein levels and suppressed NF-κB signaling and expression of inflammatory mediators. Conclusions These data suggest that LPS-induced NF-κB signaling and inflammatory mediator expression are modulated by cilia and that the blockade of primary cilium formation by Kif3a siRNA regulates TLR4-induced NF-κB signaling. We propose that primary cilia are critical for regulating NF-κB signaling events in neuroinflammation and in the innate immune response. Electronic supplementary material The online version of this article (10.1186/s12974-017-0958-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hyunjung Baek
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Pediatrics, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea
| | - Hyo Jung Shin
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea
| | - Jwa-Jin Kim
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,LES Corporation Inc., Gung-Dong 465-16, Yuseong-Gu, Daejeon, 305-335, Republic of Korea
| | - Nara Shin
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Anesthesia and Pain Medicine, Chungnam National University Hospital, Daejeon, 35015, Republic of Korea
| | - Sena Kim
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Plastic Surgery, Chungnam National University Hospital, Daejeon, 35015, Republic of Korea
| | - Min-Hee Yi
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Neuroscience and Cell Biology, The University of Texas Medical Branch School of Medicine, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Enji Zhang
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Anesthesia Medicine, Yanbian University Hospital, Yanbian, 133000, China
| | - Jinpyo Hong
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea
| | - Joon Won Kang
- Department of Pediatrics, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea
| | - Yonghyun Kim
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL, 35487, USA
| | - Cuk-Seong Kim
- Department of Physiology, Department of Medical Science, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.
| | - Dong Woon Kim
- Department of Anatomy, Department of Medical Science, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.
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18
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Gambassi S, Geminiani M, Thorpe SD, Bernardini G, Millucci L, Braconi D, Orlandini M, Thompson CL, Petricci E, Manetti F, Taddei M, Knight MM, Santucci A. Smoothened-antagonists reverse homogentisic acid-induced alterations of Hedgehog signaling and primary cilium length in alkaptonuria. J Cell Physiol 2017; 232:3103-3111. [DOI: 10.1002/jcp.25761] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/29/2016] [Accepted: 12/22/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Silvia Gambassi
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Michela Geminiani
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Stephen D. Thorpe
- Institute of Bioengineering; School of Engineering and Materials Science; Queen Mary University of London; Mile End Rd; London United Kingdom
| | - Giulia Bernardini
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Lia Millucci
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Daniela Braconi
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Maurizio Orlandini
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Clare L. Thompson
- Institute of Bioengineering; School of Engineering and Materials Science; Queen Mary University of London; Mile End Rd; London United Kingdom
| | - Elena Petricci
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Fabrizio Manetti
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Maurizio Taddei
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Martin M. Knight
- Institute of Bioengineering; School of Engineering and Materials Science; Queen Mary University of London; Mile End Rd; London United Kingdom
| | - Annalisa Santucci
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
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19
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Rowson D, Knight MM, Screen HR. Zonal variation in primary cilia elongation correlates with localized biomechanical degradation in stress deprived tendon. J Orthop Res 2016; 34:2146-2153. [PMID: 26969839 PMCID: PMC5216897 DOI: 10.1002/jor.23229] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 03/06/2016] [Indexed: 02/04/2023]
Abstract
Tenocytes express primary cilia, which elongate when tendon is maintained in the absence of biomechanical load. Previous work indicates differences in the morphology and metabolism of the tenocytes in the tendon fascicular matrix (FM) and the inter-fascicular matrix (IFM). This study tests the hypothesis that primary cilia in these two regions respond differently to stress deprivation and that this is associated with differences in the biomechanical degradation of the extracellular matrix. Rat tail tendon fascicles were examined over a 7-day period of either stress deprivation or static load. Seven days of stress deprivation induced cilia elongation in both regions. However, elongation was greater in the IFM compared to the FM. Stress deprivation also induced a loss of biomechanical integrity, primarily in the IFM. Static loading reduced both the biomechanical degradation and cilia elongation. The different responses to stress deprivation in the two tendon regions are likely to be important for the aetiology of tendinopathy. Furthermore, these data suggest that primary cilia elongate in response to biomechanical degradation rather than simply the removal of load. This response to degradation is likely to have important consequences for cilia signalling in tendon and as well as in other connective tissues. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 34:2146-2153, 2016.
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Affiliation(s)
- Daniel Rowson
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
| | - Martin M. Knight
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
| | - Hazel R.C. Screen
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
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20
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Abstract
Although solitary or sensory cilia are present in most cells of the body and their existence has been known since the sixties, very little is known about their functions. One suspected function is fluid flow sensing- physical bending of cilia produces an influx of Ca++, which can then result in a variety of activated signaling pathways. Defective cilia and ciliary-associated proteins have been shown to result in cystic diseases. Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a progressive disease, typically appearing in the 5th decade of life and is one of the most common monogenetic inherited human diseases, affecting approximately 600,000 people in the United States. Because the mechanical properties of cilia impact their response to applied flow, we asked how the stiffness of cilia can be controlled pharmacologically. We performed an experiment subjecting cilia to Taxol (a microtubule stabilizer) and CoCl2 (a HIF stabilizer to model hypoxia). Madin-Darby Canine Kidney (MDCK) cells were selected as our model system. After incubation with a selected pharmacological agent, cilia were optically trapped and the bending modulus measured. We found that HIF stabilization significantly weakens cilia. These results illustrate a method to alter the mechanical properties of primary cilia and potentially alter the flow sensing properties of cilia.
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Affiliation(s)
- Andrew Resnick
- Department of Physics, Cleveland State University, Cleveland, Ohio, United States of America.,Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, Ohio, United States of America
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21
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Yuan X, Yang S. Primary Cilia and Intraflagellar Transport Proteins in Bone and Cartilage. J Dent Res 2016; 95:1341-1349. [PMID: 27250654 DOI: 10.1177/0022034516652383] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Primary cilia, present on most mammalian cells, function as a sensor to sense the environment change and transduce signaling. Loss of primary cilia causes a group of human pleiotropic syndromes called Ciliopathies. Some of the ciliopathies display skeletal dysplasias, implying the important role of primary cilia in skeletal development and homeostasis. Emerging evidence has shown that loss or malfunction of primary cilia or ciliary proteins in bone and cartilage is associated with developmental and function defects. Intraflagellar transport (IFT) proteins are essential for cilia formation and/or function. In this review, we discuss the role of primary cilia and IFT proteins in the development of bone and cartilage, as well as the differentiation and mechanotransduction of mesenchymal stem cells, osteoblasts, osteocytes, and chondrocytes. We also include the role of primary cilia in tooth development and highlight the current advance of primary cilia and IFT proteins in the pathogenesis of cartilage diseases, including osteoarthritis, osteosarcoma, and chondrosarcoma.
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Affiliation(s)
- X Yuan
- 1 Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - S Yang
- 1 Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, NY, USA.,2 Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA
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Dinsmore C, Reiter JF. Endothelial primary cilia inhibit atherosclerosis. EMBO Rep 2016; 17:156-66. [PMID: 26769565 DOI: 10.15252/embr.201541019] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/27/2015] [Indexed: 01/23/2023] Open
Abstract
Primary cilia are microtubule-based structures present on most mammalian cells that are important for intercellular signaling. Cilia are present on a subset of endothelial cells where they project into the vessel lumen and are implicated as mechanical sensors of blood flow. To test the in vivo role of endothelial cilia, we conditionally deleted Ift88, a gene required for ciliogenesis, in endothelial cells of mice. We found that endothelial primary cilia were dispensable for mammalian vascular development. Cilia were not uniformly distributed in the mouse aorta, but were enriched at vascular branch points and sites of high curvature. These same sites are predisposed to the development of atherosclerotic plaques, prompting us to investigate whether cilia participate in atherosclerosis. Removing endothelial cilia increased atherosclerosis in Apoe(-/-) mice fed a high-fat, high-cholesterol diet, indicating that cilia protect against atherosclerosis. Removing endothelial cilia increased inflammatory gene expression and decreased eNOS activity, indicating that endothelial cilia inhibit pro-atherosclerotic signaling in the aorta.
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Affiliation(s)
- Colin Dinsmore
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute University of California, San Francisco San Francisco, CA, USA
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute University of California, San Francisco San Francisco, CA, USA
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Thompson CL, Patel R, Kelly TAN, Wann AKT, Hung CT, Chapple JP, Knight MM. Hedgehog signalling does not stimulate cartilage catabolism and is inhibited by Interleukin-1β. Arthritis Res Ther 2015; 17:373. [PMID: 26705100 PMCID: PMC4718026 DOI: 10.1186/s13075-015-0891-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/08/2015] [Indexed: 12/21/2022] Open
Abstract
Background In osteoarthritis, chondrocytes adopt an abnormal hypertrophic morphology and upregulate the expression of the extracellular matrix-degrading enzymes, MMP-13 and ADAMTS-5. The activation of the hedgehog signalling pathway has been established in osteoarthritis and is thought to influence both of these processes. However, the role of this pathway in the initiation and progression of osteoarthritis is unclear as previous studies have been unable to isolate the effects of hedgehog pathway activation from other pathological processes. In this study we test the hypothesis that hedgehog pathway activation causes cartilage degradation in healthy cartilage and in an in vitro model of inflammatory arthritis. Methods Isolated articular chondrocytes from the bovine metacarpal-phalangeal joint were stimulated for up to 24 hours with the agonist, recombinant Indian hedgehog (r-Ihh). ADAMTS-5 and MMP-13 gene expression was quantified by real-time PCR. In addition, healthy bovine cartilage explants were treated with r-Ihh or the hedgehog antagonist, cyclopamine, and sGAG release into the media was measured over 72 hours. Studies were repeated using chondrocytes and cartilage explants from human knee joint. Finally, studies were conducted to determine the effect of hedgehog pathway activation on matrix catabolism in the presence of the pro-inflammatory cytokine, IL-1β. Results Addition of r-Ihh activated hedgehog signalling, confirmed by upregulation of Gli1 and Ptch1 expression, but did not increase ADAMTS-5 or MMP-13 expression in bovine or human chondrocytes. Furthermore, r-Ihh did not induce sGAG release in healthy bovine or human cartilage explants. IL-1β treatment induced sGAG release, but this response was not altered by the stimulation or inhibition of hedgehog signalling. Hedgehog pathway activation was downregulated by IL-1β. Conversely, r-Ihh weakly suppressed IL-1β-induced ADAMTS-5 expression. Conclusion Our results show for the first time that Indian hedgehog does not cause extracellular matrix degradation in healthy ex vivo cartilage or in the presence of IL-1β and that IL-1β downregulates Indian hedgehog induced signalling. Thus, we suggest reported hedgehog induced matrix catabolism in osteoarthritis must be due to its interaction with pathological factors other than IL-1β. Hence, hedgehog signalling and its downstream effects are highly context-dependent. Electronic supplementary material The online version of this article (doi:10.1186/s13075-015-0891-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Clare L Thompson
- Institute of Bioengineering and School of Engineering and Material Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Riana Patel
- Institute of Bioengineering and School of Engineering and Material Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Terri-Ann N Kelly
- Institute of Bioengineering and School of Engineering and Material Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK. .,Department of Biomedical Engineering, Columbia University, New York, NY, USA.
| | - Angus K T Wann
- Institute of Bioengineering and School of Engineering and Material Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK. .,Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK.
| | - Clark T Hung
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
| | - J Paul Chapple
- Center for Endocrinology, William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, UK.
| | - Martin M Knight
- Institute of Bioengineering and School of Engineering and Material Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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The chondrocyte primary cilium. Osteoarthritis Cartilage 2014; 22:1071-6. [PMID: 24879961 DOI: 10.1016/j.joca.2014.05.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 04/29/2014] [Accepted: 05/07/2014] [Indexed: 02/02/2023]
Abstract
UNLABELLED The presence and role of primary, or non-motile, cilia on chondrocytes has confused cartilage researchers for decades. Initial explanations attributed a vestigial nature to chondrocyte cilia. Evidence is now emerging that supports the role of the chondrocyte primary cilium as a sensory organelle, in particular, in mechanotransduction and as a compartment for signaling pathways. Early electron microscopy images depicted bent cilia aligned with the extracellular matrix (ECM) in a manner that suggested a response to mechanical forces. Molecules known to be mechanotransducers in other cell types, including integrins and proteoglycans, are present on chondrocyte cilia. Further, chondrocytes which lack cilia fail to respond to mechanical forces in the same manner that chondrocytes with intact cilia respond. From a clinical perspective, chondrocytes from osteoarthritic (OA) cartilage have cilia with different characteristics than cilia found on chondrocytes from healthy cartilage. OBJECTIVE This review examines the evidence supporting the function of chondrocyte cilia and briefly speculates on the involvement of intraflagellar transport (IFT) in the signaling pathway of mechanotransduction through the cilium. CONCLUSIONS Emerging evidence suggests cilia may be a promising target for preventing and treating OA.
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Primary cilium-associated genes mediate bone marrow stromal cell response to hypoxia. Stem Cell Res 2014; 13:284-99. [PMID: 25171775 DOI: 10.1016/j.scr.2014.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/27/2014] [Accepted: 06/28/2014] [Indexed: 12/26/2022] Open
Abstract
Currently there is intense interest in using mesenchymal stem cells (MSC) for therapeutic interventions in many diseases and conditions. To accelerate the therapeutic use of stem cells we must understand how they sense their environment. Primary cilia are an extracellular sensory organelle present on most growth arrested cells that transduce information about the cellular environment into cells, triggering signaling cascades that have profound effects on development, cell cycle, proliferation, differentiation and migration. Migrating cells likely encounter differing oxygen tensions, therefore we investigated the effect of oxygen tension on cilia. Using bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) we found that oxygen tension significantly affected the length of cilia in primary BMSCs. Chronic exposure to hypoxia specifically down-regulated genes involved in hedgehog signaling and re-localized the Smo and Gli2 proteins to cilia. Investigating the effects of chemotactic migration on cilia, we observed significantly longer cilia in migrating cells which was again, strongly influenced by oxygen tension. Finally, using computational modeling we identified links between migration and ciliation signaling pathways, characterizing the novel role of HSP90 and PI3K signaling in regulating BMSC cilia length. These findings enhance our current understanding of BMSC adaptions to hypoxia and advance our knowledge of BMSC biology and cilia regulation.
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Wann AKT, Chapple JP, Knight MM. The primary cilium influences interleukin-1β-induced NFκB signalling by regulating IKK activity. Cell Signal 2014; 26:1735-42. [PMID: 24726893 PMCID: PMC4064300 DOI: 10.1016/j.cellsig.2014.04.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/01/2014] [Accepted: 04/04/2014] [Indexed: 01/02/2023]
Abstract
The primary cilium is an organelle acting as a master regulator of cellular signalling. We have previously shown that disruption of primary cilia assembly, through targeting intraflagellar transport, is associated with muted nitric oxide and prostaglandin responses to the inflammatory cytokine interleukin-1β (IL-1β). Here, we show that loss of the primary cilium disrupts specific molecular signalling events in cytosolic NFκB signalling. The induction of cyclooxygenase 2 (COX2) and inducible nitrous oxide synthase (iNOS) protein is abolished. Cells unable to assemble cilia exhibit unaffected activation of IκB kinase (IKK), but delayed and reduced degradation of IκB, due to diminished phosphorylation of inhibitor of kappa B (IκB) by IKK. This results in both delayed and reduced NFκB p65 nuclear translocation and nuclear transcript binding. We also demonstrate that heat shock protein 27 (hsp27), an established regulator of IKK, is localized to the ciliary axoneme and cellular levels are dramatically disrupted with loss of the primary cilium. These results suggest that the primary cilia compartment exerts influence over NFκB signalling. We propose that the cilium is a locality for regulation of the molecular events defining NFκB signalling events, tuning signalling as appropriate. Hypermorphic mutation of IFT88 results in partial loss of the primary cilium. Cilia loss leads to inhibition of COX2 and iNOS induction in response to IL-1. In cells without cilia, IKK is activated but does not phosphorylate IκB. This leads to sustained IκB expression, and reduced and mistimed NFκB signalling. We propose the cilium to be a location for hsp27 regulation of IKK activity.
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Affiliation(s)
- A K T Wann
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, Bancroft Road, Mile End, London E1 4NS, United Kingdom.
| | - J P Chapple
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, John Vane science building, Charterhouse square, London EC1M 6BQ, United Kingdom.
| | - M M Knight
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, Bancroft Road, Mile End, London E1 4NS, United Kingdom.
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