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Johnston SN, Tsingas M, Ain R, Barve RA, Risbud MV. Increased HIF-2α activity in the nucleus pulposus causes intervertebral disc degeneration in the aging mouse spine. Front Cell Dev Biol 2024; 12:1360376. [PMID: 38510179 PMCID: PMC10950937 DOI: 10.3389/fcell.2024.1360376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/21/2024] [Indexed: 03/22/2024] Open
Abstract
Hypoxia-inducible factors (HIFs) are essential to the homeostasis of hypoxic tissues. Although HIF-2α, is expressed in nucleus pulposus (NP) cells, consequences of elevated HIF-2 activity on disc health remains unknown. We expressed HIF-2α with proline to alanine substitutions (P405A; P531A) in the Oxygen-dependent degradation domain (HIF-2αdPA) in the NP tissue using an inducible, nucleus pulposus-specific K19CreERT allele to study HIF-2α function in the adult intervertebral disc. Expression of HIF-2α in NP impacted disc morphology, as evident from small but significantly higher scores of degeneration in NP of 24-month-old K19CreERT; HIF-2αdPA (K19-dPA) mice. Noteworthy, comparisons of grades within each genotype between 14 months and 24 months indicated that HIF-2α overexpression contributed to more pronounced changes than aging alone. The annulus fibrosus (AF) compartment in the 14-month-old K19-dPA mice exhibited lower collagen turnover and Fourier transform-infrared (FTIR) spectroscopic imaging analyses showed changes in the biochemical composition of the 14- and 24-month-old K19-dPA mice. Moreover, there were changes in aggrecan, chondroitin sulfate, and COMP abundance without alterations in NP phenotypic marker CA3, suggesting the overexpression of HIF-2α had some impact on matrix composition but not the cell phenotype. Mechanistically, the global transcriptomic analysis showed enrichment of differentially expressed genes in themes closely related to NP cell function such as cilia, SLIT/ROBO pathway, and HIF/Hypoxia signaling at both 14- and 24-month. Together, these findings underscore the role of HIF-2α in the pathogenesis of disc degeneration in the aged spine.
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Affiliation(s)
- Shira N. Johnston
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
- Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, PA, United States
| | - Maria Tsingas
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
- Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, PA, United States
| | - Rahatul Ain
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
- Graduate Program in Pharmacology, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, PA, United States
| | - Ruteja A. Barve
- Department of Genetics, Genome Technology Access Centre at the McDonnell Genome Institute, Washington University, School of Medicine, St. Louis, MO, United States
| | - Makarand V. Risbud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
- Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, PA, United States
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Johnston SN, Tsingas M, Ain R, Barve RA, Risbud MV. Increased HIF-2α Activity in the Nucleus Pulposus Causes Intervertebral Disc Degeneration in the Aging Mouse Spine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573086. [PMID: 38187709 PMCID: PMC10769411 DOI: 10.1101/2023.12.22.573086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Hypoxia-inducible factors (HIFs) are essential to the homeostasis of hypoxic tissues. Although HIF-2α, is expressed in nucleus pulposus (NP) cells, consequences of elevated HIF-2 activity on disc health remains unknown. We expressed HIF-2α with proline to alanine substitutions (P405A;P531A) in the Oxygen-dependent degradation domain (HIF-2αdPA) in the NP tissue using an inducible, nucleus pulposus-specific K19 CreERT allele to study HIF-2α function in the adult intervertebral disc. Expression of HIF-2α in NP impacted disc morphology, as evident from small but significantly higher scores of degeneration in NP of 24-month-old K19 CreERT ; HIF-2α dPA (K19-dPA) mice. Noteworthy, comparisons of grades within each genotype between 14 months and 24 months indicated that HIF-2α overexpression contributed to more pronounced changes than aging alone. The annulus fibrosus (AF) compartment in the 14-month-old K19-dPA mice exhibited lower collagen turnover and Fourier transform-infrared (FTIR) spectroscopic imaging analyses showed changes in the biochemical composition of the 14-and 24-month-old K19-dPA mice. Moreover, there were changes in aggrecan, chondroitin sulfate, and COMP abundance without alterations in NP phenotypic marker CA3, suggesting the overexpression of HIF-2α had some impact on matrix composition but not the cell phenotype. Mechanistically, the global transcriptomic analysis showed enrichment of differentially expressed genes in themes closely related to NP cell function such as cilia, SLIT/ROBO pathway, and HIF/Hypoxia signaling at both 14- and 24-months. Together, these findings underscore the role of HIF-2α in the pathogenesis of disc degeneration in the aged spine.
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Tian JL, Huang CW, Eslami F, Mannino MP, Mai RL, Hart GW. Regulation of Primary Cilium Length by O-GlcNAc during Neuronal Development in a Human Neuron Model. Cells 2023; 12:1520. [PMID: 37296641 PMCID: PMC10252524 DOI: 10.3390/cells12111520] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
The primary cilium plays critical roles in the homeostasis and development of neurons. Recent studies demonstrate that cilium length is regulated by the metabolic state of cells, as dictated by processes such as glucose flux and O-GlcNAcylation (OGN). The study of cilium length regulation during neuron development, however, has been an area left largely unexplored. This project aims to elucidate the roles of O-GlcNAc in neuronal development through its regulation of the primary cilium. Here, we present findings suggesting that OGN levels negatively regulate cilium length on differentiated cortical neurons derived from human-induced pluripotent stem cells. In neurons, cilium length increased significantly during maturation (after day 35), while OGN levels began to drop. Long-term perturbation of OGN via drugs, which inhibit or promote its cycling, during neuron development also have varying effects. Diminishing OGN levels increases cilium length until day 25, when neural stem cells expand and undergo early neurogenesis, before causing cell cycle exit defects and multinucleation. Elevating OGN levels induces greater primary cilia assembly but ultimately results in the development of premature neurons, which have higher insulin sensitivity. These results indicate that OGN levels and primary cilium length are jointly critical in proper neuron development and function. Understanding the interplays between these two nutrient sensors, O-GlcNAc and the primary cilium, during neuron development is important in paving connections between dysfunctional nutrient-sensing and early neurological disorders.
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Affiliation(s)
- Jie L. Tian
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.-W.H.); (F.E.); (M.P.M.); (R.L.M.)
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Chia-Wei Huang
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.-W.H.); (F.E.); (M.P.M.); (R.L.M.)
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Farzad Eslami
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.-W.H.); (F.E.); (M.P.M.); (R.L.M.)
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Michael Philip Mannino
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.-W.H.); (F.E.); (M.P.M.); (R.L.M.)
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Rebecca Lee Mai
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.-W.H.); (F.E.); (M.P.M.); (R.L.M.)
- Department of Biology, University of Georgia, Athens, GA 30602, USA
| | - Gerald W. Hart
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (C.-W.H.); (F.E.); (M.P.M.); (R.L.M.)
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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Liu J, Leng F, Gao Y, He W, Wang J, Xian CJ, Ma H, Chen K. Protection of primary cilia is an effective countermeasure against the impairment of osteoblast function induced by simulated microgravity. J Cell Mol Med 2022; 27:36-51. [PMID: 36512344 PMCID: PMC9806295 DOI: 10.1111/jcmm.17628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 12/15/2022] Open
Abstract
The molecular mechanism for the microgravity-induced decrease in bone formation remains unclear and there is a lack of effective specific preventative therapies. We recently reported that primary cilia of osteoblasts became shorter and even disappeared when the cells were exposed to random positioning machine (RPM)-simulated microgravity and that the microgravity-induced loss of osteogenic potential of osteoblasts could be attenuated when the resorption of primary cilia was prevented by treatment with 0.1 μM cytochalasin D. In the current study, it was further found that the loss of the osteogenic capacity of rat calvarial osteoblasts (ROBs) was associated with the inhibition of the BMP-2/Smad1/5/8 signalling pathway, of which most of the signalling proteins including BMP-2, BMPRII, Smad1/5/8 and p-Smad1/5/8 were found localized to primary cilia. Accompanying the resorption of primary cilia following the cells being exposed to simulated microgravity, the expression levels of these signalling proteins were reduced significantly. Furthermore, the expression of miRNA-129-3p, a microRNA previously reported to control cilium biogenesis, was found to be reduced quickly and changed in a similar tendency with the length of primary cilia. Moreover, overexpression of miRNA-129-3p in ROBs significantly attenuated microgravity-induced inhibition of BMP-2 signalling and loss of osteogenic differentiation and mineralization. These results indicated the important role of miRNA-129-3p in microgravity-induced resorption of primary cilia of osteoblasts and the potential of replenishing the miRNA-129-3p as an effective countermeasure against microgravity-induced loss of primary cilia and impairment of osteoblast function.
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Affiliation(s)
- Jing Liu
- Fundamental Medical Science Research Laboratories, The 940th Hospital of Joint Logistic Support ForcePeople's Liberation Army of ChinaLanzhouChina
| | - Fei‐Fan Leng
- Department of Bioengineering, School of Life Science and EngineeringLanzhou University of TechnologyLanzhouChina
| | - Yu‐Hai Gao
- Fundamental Medical Science Research Laboratories, The 940th Hospital of Joint Logistic Support ForcePeople's Liberation Army of ChinaLanzhouChina
| | - Wen‐Fang He
- Fundamental Medical Science Research Laboratories, The 940th Hospital of Joint Logistic Support ForcePeople's Liberation Army of ChinaLanzhouChina
| | - Ju‐Fang Wang
- Gansu Key Laboratory of Space RadiobiologyInstitute of Modern Physics, Chinese Academy of SciencesLanzhouChina
| | - Cory J. Xian
- UniSA Clinical and Health SciencesUniversity of South AustraliaAdelaideSouth AustraliaAustralia
| | - Hui‐Ping Ma
- Department of Pharmacy, The 940th Hospital of Joint Logistic Support ForcePeople's Liberation Army of ChinaLanzhouChina
| | - Ke‐Ming Chen
- Fundamental Medical Science Research Laboratories, The 940th Hospital of Joint Logistic Support ForcePeople's Liberation Army of ChinaLanzhouChina
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Role of Primary Cilia in Skeletal Disorders. Stem Cells Int 2022; 2022:6063423. [PMID: 35761830 PMCID: PMC9233574 DOI: 10.1155/2022/6063423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/23/2022] [Accepted: 06/03/2022] [Indexed: 11/26/2022] Open
Abstract
Primary cilia are highly conserved microtubule-based organelles that project from the cell surface into the extracellular environment and play important roles in mechanosensation, mechanotransduction, polarity maintenance, and cell behaviors during organ development and pathological changes. Intraflagellar transport (IFT) proteins are essential for cilium formation and function. The skeletal system consists of bones and connective tissue, including cartilage, tendons, and ligaments, providing support, stability, and movement to the body. Great progress has been achieved in primary cilia and skeletal disorders in recent decades. Increasing evidence suggests that cells with cilium defects in the skeletal system can cause numerous human diseases. Moreover, specific deletion of ciliary proteins in skeletal tissues with different Cre mice resulted in diverse malformations, suggesting that primary cilia are involved in the development of skeletal diseases. In addition, the intact of primary cilium is essential to osteogenic/chondrogenic induction of mesenchymal stem cells, regarded as a promising target for clinical intervention for skeletal disorders. In this review, we summarized the role of primary cilia and ciliary proteins in the pathogenesis of skeletal diseases, including osteoporosis, bone/cartilage tumor, osteoarthritis, intervertebral disc degeneration, spine scoliosis, and other cilium-related skeletal diseases, and highlighted their promising treatment methods, including using mesenchymal stem cells. Our review tries to present evidence for primary cilium as a promising target for clinical intervention for skeletal diseases.
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Baldi P, Alhassen W, Chen S, Nguyen H, Khoudari M, Alachkar A. Large-scale analysis reveals spatiotemporal circadian patterns of cilia transcriptomes in the primate brain. J Neurosci Res 2021; 99:2610-2624. [PMID: 34310750 PMCID: PMC11391745 DOI: 10.1002/jnr.24919] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/08/2021] [Accepted: 06/24/2021] [Indexed: 01/13/2023]
Abstract
Cilia are dynamic subcellular systems, with core structural and functional components operating in a highly coordinated manner. Since many environmental stimuli sensed by cilia are circadian in nature, it is reasonable to speculate that genes encoding cilia structural and functional components follow rhythmic circadian patterns of expression. Using computational methods and the largest spatiotemporal gene expression atlas of primates, we identified and analyzed the circadian rhythmic expression of cilia genes across 22 primate brain areas. We found that around 73% of cilia transcripts exhibited circadian rhythmicity across at least one of 22 brain regions. In 12 brain regions, cilia transcriptomes were significantly enriched with circadian oscillating transcripts, as compared to the rest of the transcriptome. The phase of the cilia circadian transcripts deviated from the phase of the majority of the background circadian transcripts, and transcripts coding for cilia basal body components accounted for the majority of cilia circadian transcripts. In addition, adjacent or functionally connected brain nuclei had large overlapping complements of circadian cilia genes. Most remarkably, cilia circadian transcripts shared across the basal ganglia nuclei and the prefrontal cortex peaked in these structures in sequential fashion that is similar to the sequential order of activation of the basal ganglia-cortical circuitry in connection with movement coordination, albeit on completely different timescales. These findings support a role for the circadian spatiotemporal orchestration of cilia gene expression in the normal physiology of the basal ganglia-cortical circuit and motor control. Studying orchestrated cilia rhythmicity in the basal ganglia-cortical circuits and other brain circuits may help develop better functional models, and shed light on the causal effects cilia functions have on these circuits and on the regulation of movement and other behaviors.
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Affiliation(s)
- Pierre Baldi
- Department of Computer Science, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA
| | - Wedad Alhassen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California-Irvine, Irvine, CA, USA
| | - Siwei Chen
- Department of Computer Science, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA
| | - Henry Nguyen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California-Irvine, Irvine, CA, USA
| | - Mohammad Khoudari
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California-Irvine, Irvine, CA, USA
| | - Amal Alachkar
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California-Irvine, Irvine, CA, USA
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