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Fu Z, Zhao PY, Yang XP, Li H, Hu SD, Xu YX, Du XH. Cannabidiol regulates apoptosis and autophagy in inflammation and cancer: A review. Front Pharmacol 2023; 14:1094020. [PMID: 36755953 PMCID: PMC9899821 DOI: 10.3389/fphar.2023.1094020] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/11/2023] [Indexed: 01/24/2023] Open
Abstract
Cannabidiol (CBD) is a terpenoid naturally found in plants. The purified compound is used in the treatment of mental disorders because of its antidepressive, anxiolytic, and antiepileptic effects. CBD can affect the regulation of several pathophysiologic processes, including autophagy, cytokine secretion, apoptosis, and innate and adaptive immune responses. However, several authors have reported contradictory findings concerning the magnitude and direction of CBD-mediated effects. For example, CBD treatment can increase, decrease, or have no significant effect on autophagy and apoptosis. These variable results can be attributed to the differences in the biological models, cell types, and CBD concentration used in these studies. This review focuses on the mechanism of regulation of autophagy and apoptosis in inflammatory response and cancer by CBD. Further, we broadly elaborated on the prospects of using CBD as an anti-inflammatory agent and in cancer therapy in the future.
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Affiliation(s)
- Ze Fu
- Medical School of Chinese PLA, Beijing, China
| | | | | | - Hao Li
- Medical School of Chinese PLA, Beijing, China
| | - Shi-Dong Hu
- Department of General Surgery, First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Ying-Xin Xu
- Department of General Surgery, First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Xiao-Hui Du
- Department of General Surgery, First Medical Center of Chinese PLA General Hospital, Beijing, China,*Correspondence: Xiao-Hui Du,
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Abstract
Transforming growth factor-beta2 (TGF-β2) is recognized as a versatile cytokine that plays a vital role in regulation of joint development, homeostasis, and diseases, but its role as a biological mechanism is understood far less than that of its counterpart, TGF-β1. Cartilage as a load-resisting structure in vertebrates however displays a fragile performance when any tissue disturbance occurs, due to its lack of blood vessels, nerves, and lymphatics. Recent reports have indicated that TGF-β2 is involved in the physiological processes of chondrocytes such as proliferation, differentiation, migration, and apoptosis, and the pathological progress of cartilage such as osteoarthritis (OA) and rheumatoid arthritis (RA). TGF-β2 also shows its potent capacity in the repair of cartilage defects by recruiting autologous mesenchymal stem cells and promoting secretion of other growth factor clusters. In addition, some pioneering studies have already considered it as a potential target in the treatment of OA and RA. This article aims to summarize the current progress of TGF-β2 in cartilage development and diseases, which might provide new cues for remodelling of cartilage defect and intervention of cartilage diseases.
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Affiliation(s)
- Mengmeng Duan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qingxuan Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yang Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Upadhyai P, Radhakrishnan P, Guleria VS, Kausthubham N, Nayak SS, Superti-Furga A, Girisha KM. Biallelic deep intronic variant c.5457+81T>A in TRIP11 causes loss of function and results in achondrogenesis 1A. Hum Mutat 2021; 42:1005-1014. [PMID: 34057271 DOI: 10.1002/humu.24235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/18/2021] [Accepted: 05/26/2021] [Indexed: 11/09/2022]
Abstract
Biallelic loss of function variants in TRIP11 encoding for the Golgi microtubule-associated protein 210 (GMAP-210) causes the lethal chondrodysplasia achondrogenesis type 1A (ACG1A). Loss of TRIP11 activity has been shown to impair Golgi structure, vesicular transport, and results in loss of IFT20 anchorage to the Golgi that is vital for ciliary trafficking and ciliogenesis. Here, we report four fetuses, two each from two families, who were ascertained antenatally with ACG1A. Affected fetuses in both families are homozygous for the deep intronic TRIP11 variant, c.5457+81T>A, which was found in a shared region of homozygosity. This variant was found to cause aberrant transcript splicing and the retention of 77 base pairs of intron 18. The TRIP11 messenger RNA and protein levels were drastically reduced in fibroblast cells derived from one of the affected fetuses. Using immunofluorescence we also detected highly compacted Golgi apparatus in affected fibroblasts. Further, we observed a significant reduction in the frequency of ciliated cells and in the length of primary cilia in subject-derived cell lines, not reported so far in patient cells with TRIP11 null or hypomorphic variants. Our findings illustrate how pathogenic variants in intronic regions of TRIP11 can impact transcript splicing, expression, and activity, resulting in ACG1A.
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Affiliation(s)
- Priyanka Upadhyai
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Periyasamy Radhakrishnan
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Vishal S Guleria
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Neethukrishna Kausthubham
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Shalini S Nayak
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Andrea Superti-Furga
- Division of Genetic Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Katta M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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4
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Wang Y, Xiu J, Ren C, Yu Z. Protein kinase PIM2: A simple PIM family kinase with complex functions in cancer metabolism and therapeutics. J Cancer 2021; 12:2570-2581. [PMID: 33854618 PMCID: PMC8040705 DOI: 10.7150/jca.53134] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/12/2021] [Indexed: 12/13/2022] Open
Abstract
PIM2 (proviral integration site for Moloney murine leukemia virus 2) kinase plays an important role as an oncogene in multiple cancers, such as leukemia, liver, lung, myeloma, prostate and breast cancers. PIM2 is largely expressed in both leukemia and solid tumors, and it promotes the transcriptional activation of genes involved in cell survival, cell proliferation, and cell-cycle progression. Many tumorigenic signaling molecules have been identified as substrates for PIM2 kinase, and a variety of inhibitors have been developed for its kinase activity, including SMI-4a, SMI-16a, SGI-1776, JP11646 and DHPCC-9. Here, we summarize the signaling pathways involved in PIM2 kinase regulation and PIM2 mechanisms in various neoplastic diseases. We also discuss the current status and future perspectives for the development of PIM2 kinase inhibitors to combat human cancer, and PIM2 will become a therapeutic target in cancers in the future.
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Affiliation(s)
- Yixin Wang
- Department of Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, Shandong Province, P.R. China
| | - Jing Xiu
- Department of Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, Shandong Province, P.R. China
| | - Chune Ren
- Department of Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, Shandong Province, P.R. China
| | - Zhenhai Yu
- Department of Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, Shandong Province, P.R. China
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Brigant B, Demont Y, Ouled-Haddou H, Metzinger-Le Meuth V, Testelin S, Garçon L, Metzinger L, Rochette J. TRIM37 is highly expressed during mitosis in CHON-002 chondrocytes cell line and is regulated by miR-223. Bone 2020; 137:115393. [PMID: 32353567 DOI: 10.1016/j.bone.2020.115393] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/24/2020] [Accepted: 04/24/2020] [Indexed: 02/06/2023]
Abstract
Multiple molecular disorders can affect mechanisms regulating proliferation and differentiation of growth plate chondrocytes. Mutations in the TRIM37 gene cause the Mulibrey nanism, a heritable growth disorder. Since chondrocytes are instrumental in long bone growth that is deficient in nanism, we hypothesized that TRIM37 defect could contribute to dysregulation of the chondrocyte cell cycle. Western blotting, confocal microscopy and imaging flow cytometry determined TRIM37 expression in CHON-002 cell lineage. We showed that TRIM37 is expressed during mitosis of chondrocytes and directly impacted their proliferation. During the chondrocyte cell cycle, TRIM37 was present in both nucleus and cytoplasm. During M phase we observed an increase of the TRIM37-Tubulin co-localization in comparison with G1, S and G2 phases. TRIM37 knock down inhibited proliferation, together with cell cycle anomalies and increased autophagy, while overexpression accordingly enhanced cell proliferation. We demonstrated that microRNA-223 directly targets TRIM37, and suggest that miR-223 regulates TRIM37 gene expression during the cell cycle. In summary, our results give clues to explain why TRIM37 deficiency in chondrocytes impacts bone growth. Modulating TRIM37 using miR-223 could be an approach to increase chondrogenesis.
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Affiliation(s)
- Benjamin Brigant
- HEMATIM EA4666, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France
| | - Yohann Demont
- HEMATIM EA4666, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France
| | - Hakim Ouled-Haddou
- HEMATIM EA4666, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France
| | | | - Sylvie Testelin
- Maxillo-Facial Surgery Department, Centre Hospitalo-Universitaire d'Amiens, Avenue Laennec, 80000 Amiens, France; EA CHIMERE, université de Picardie-Jules-Verne, Avenue Laennec, 80000 Amiens, France; Facing Faces Institute, Avenue Laennec, 80000 Amiens, France
| | - Loïc Garçon
- HEMATIM EA4666, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France
| | - Laurent Metzinger
- HEMATIM EA4666, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France
| | - Jacques Rochette
- HEMATIM EA4666, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France.
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6
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Xiang H, Zhang J, Lin C, Zhang L, Liu B, Ouyang L. Targeting autophagy-related protein kinases for potential therapeutic purpose. Acta Pharm Sin B 2020; 10:569-581. [PMID: 32322463 PMCID: PMC7161711 DOI: 10.1016/j.apsb.2019.10.003] [Citation(s) in RCA: 145] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 08/06/2019] [Accepted: 09/09/2019] [Indexed: 02/08/2023] Open
Abstract
Autophagy, defined as a scavenging process of protein aggregates and damaged organelles mediated by lysosomes, plays a significant role in the quality control of macromolecules and organelles. Since protein kinases are integral to the autophagy process, it is critically important to understand the role of kinases in autophagic regulation. At present, intervention of autophagic processes by small-molecule modulators targeting specific kinases has becoming a reasonable and prevalent strategy for treating several varieties of human disease, especially cancer. In this review, we describe the role of some autophagy-related kinase targets and kinase-mediated phosphorylation mechanisms in autophagy regulation. We also summarize the small-molecule kinase inhibitors/activators of these targets, highlighting the opportunities of these new therapeutic agents.
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Key Words
- 4E-BP1, eukaryotic translation initiation factor 4E-binding protein
- AKT1, AKT serine/threonine kinase 1
- AMBRA1, autophagy/beclin-1 regulator 1
- AMPK, AMP-activated protein kinase
- ARF, auxin response factor gene
- ATG, autophagy-related protein
- Autophagy
- Autophagy-related kinase
- CaMKK2, calcium/calmodulin-dependent protein kinase kinase 2
- DAPK, death associated protein kinase
- FIP200, FAK family kinase-interacting protein of 200 kDa
- GAP, GTPase-activating protein
- GO, gene ontology
- GSK3α, glycogen synthase kinase 3 alpha
- HMGB1, high mobility group protein B1
- Human disease therapy
- JNK1, C-Jun N-terminal kinase
- LC3, microtubule-associated protein 1 light chain 3
- LKB1, serine/threonine-protein kinase stk11
- LPS, lipopolysaccharide
- LRRK2, leucine rich repeat kinase 2
- PD, Parkinson's disease
- PI, phosphatidylinositol
- PI3 kinase, phosphoinositide 3-kinase
- PI3P, phosphatidylinositol triphosphate
- PIM2, proviral insertion in murine lymphomas 2
- PINK1, PTEN-induced putative kinase 1
- PIP2, phosphatidylinositol-4,5-bisphosphate
- PKACα, a protein kinase cAMP-activated catalytic subunit alpha
- PKCα, protein kinase C alpha type
- PKD1, polycystin-1
- PPIs, protein–protein interactions
- PROTAC, proteolysis targeting chimeras
- PTMs, post-translational modifications
- Phosphorylation
- Protein kinases
- Rheb, the RAS homolog enriched in brain
- Small-molecule kinase inhibitors/activators
- TAK1, transforming growth factor activated kinase-1
- TFEB, transcription factor EB
- TNBC, triple-negative breast cancer
- TSC1/2, tuberous sclerosis complex proteins 1/2
- ULK complex, ULK1–mATG13–FIP200–ATG101 complex
- ULK1, unc-51-like kinase 1
- UVRAG, ultraviolet resistance-associated gene
- mTOR, mammalian target of rapamycin
- mTORC1, mammalian target of rapamycin complex 1
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Affiliation(s)
- Honggang Xiang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Jifa Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Congcong Lin
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Lan Zhang
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Bo Liu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Liang Ouyang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210023, China
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7
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Chlorogenic Acid Alleviates Thiram-Induced Tibial Dyschondroplasia by Modulating Caspases, BECN1 Expression and ECM Degradation. Int J Mol Sci 2019; 20:ijms20133160. [PMID: 31261680 PMCID: PMC6651234 DOI: 10.3390/ijms20133160] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 06/24/2019] [Accepted: 06/26/2019] [Indexed: 12/13/2022] Open
Abstract
Chlorogenic acid (CGA) is a widely applied traditional Chinese medicine ingredient which can be used for the treatment of osteoporosis. In this experiment, we investigated the potential therapeutic effect of chlorogenic acid on thiram-induced tibial dyschondroplasia (TD) and explored the underlying mechanisms that have been rarely mentioned by others yet. Performance indicator analysis and tibial parameter analysis showed that CGA exhibited a definite positive effect on thiram-induced TD chickens. In order to further explore the mechanisms underlying the positive actions of CGA, apoptotic, autophagic genes and MMPs involved in matrix mineralization of growth plate were evaluated in this study. The results showed that CGA decreased the expression of pro-apoptotic genes caspases-3 and caspases-9, leading to the reduction of apoptotic cells accumulated in growth plate. In addition, CGA also increased the level of BECN1, an important gene involved in autophagy, which benefits the survival of abnormal cells. Furthermore, CGA also increased the expression of MMP-9, MMP-10, and MMP-13, which can directly affect the ossification of bones. Altogether, these results demonstrate that CGA possesses a positive therapeutic effect on thiram-induced TD via modulating the expression of caspases and BECN1 and regulating the degradation of ECM (extracellular matrix).
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Ma X, Du T, Zhu D, Chen X, Lai Y, Wu W, Wang Q, Lin C, Li Z, Liu L, Huang H. High levels of glioma tumor suppressor candidate region gene 1 predicts a poor prognosis for prostate cancer. Oncol Lett 2018; 16:6749-6755. [PMID: 30405818 DOI: 10.3892/ol.2018.9490] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 06/08/2018] [Indexed: 11/06/2022] Open
Abstract
Glioma tumor suppressor candidate region gene 1 (GLTSCR1) is associated with the progression of oligodendroglioma. However, there has been little study of GLTSCR1 in prostate cancer. In the present study, the association between the expression of GLTSCR1, and the progression and prognosis of tumors in patients with prostate cancer was assessed. An immunohistochemical analysis was performed using a human tissue microarray for GLTSCR1 at the protein expression level and the immunostaining results were evaluated against clinical variables of patients with prostate cancer. Subsequently, The Cancer Genome Atlas (TCGA) was used to validate the analysis results at the mRNA level and to study the prognostic value of GLTSCR1 in prostate cancer. Immunohistochemistry and TCGA data analysis revealed that GLTSCR1 expression in the prostate cancer tissues was significantly higher than that in the benign prostate tissues (immunoreactivity score, P=0.015; mRNA levels: cancer, 447.7±6.45 vs. benign, 343.5±4.21; P<0.001). Additionally, the increased GLTSCR1 protein expression was associated with certain clinical variables in the prostate cancer tissues, including advanced clinical stage (P<0.001), enhanced tumor invasion (P=0.003), lymph node metastasis (P=0.003) and distant metastasis (P=0.001). TCGA data revealed similar results, demonstrating that the upregulation of GLTSCR1 mRNA expression was associated with the Gleason score (P<0.001), enhanced tumor invasion (P=0.011), lymph node metastasis (P=0.001) and distant metastasis (P=0.002). Furthermore, Kaplan-Meier analysis suggested that among all patients, high GLTSCR1 expression indicated a decreased overall survival (P=0.028) and biochemical recurrence (BCR)-free survival (P=0.004), compared with patients with low GLTSCR1 expression. Finally, multivariate analysis revealed that the expression of GLTSCR1 was an independent predictor of poor BCR-free survival (P=0.049). The present study suggested that the increased expression of GLTSCR1 was associated with the progression of prostate cancer. Furthermore, GLTSCR1 may be a novel biomarker that is able to predict the clinical outcome in prostate cancer patients.
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Affiliation(s)
- Xiaoming Ma
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Tao Du
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.,Department of Obstetrics and Gynecology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Dingjun Zhu
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Xianju Chen
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Yiming Lai
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Wanhua Wu
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Qiong Wang
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Chunhao Lin
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Zean Li
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Leyuan Liu
- Center for Translational Cancer Research, Texas A&M Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA.,Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Hai Huang
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.,Center for Translational Cancer Research, Texas A&M Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA
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9
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Sun W, Li Y, Wei S. miR-4262 regulates chondrocyte viability, apoptosis, autophagy by targeting SIRT1 and activating PI3K/AKT/mTOR signaling pathway in rats with osteoarthritis. Exp Ther Med 2017; 15:1119-1128. [PMID: 29434702 DOI: 10.3892/etm.2017.5444] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 10/16/2017] [Indexed: 01/12/2023] Open
Abstract
The present study aimed to investigate the effect and underlying mechanism of microRNA (miR)-4262 in the development of osteoarthritis (OA) in rats. Primary chondrocytes were separated from Sprague-Dawley rats and then treated with tumor necrosis factor-α (TNF-α). The level of miR-4262 was detected in TNF-α-treated chondrocytes, and then the miR-4262 or its target gene sirtuin type 1 (SIRT1) level was overexpressed, or knocked down. Furthermore, cell viability, cell apoptosis, cell autophagy and matrix synthesis, as well as the expressions of proteins associated with the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway were detected. miR-4262 was significantly overexpressed in TNF-α-treated chondrocytes compared with untreated cells (P<0.05). TNF-α treatment or miR-4262 overexpression significantly decreased cell viability, autophagy-related proteins levels and matrix synthesis-related proteins levels, as well as increased the apoptotic rate in chondrocytes (P<0.05). Overexpression of SIRT1 significantly increased cell viability, autophagy-related proteins levels and matrix synthesis-related proteins levels, as well as decreased the apoptotic rate in TNF-α-treated chondrocytes (P<0.05). In addition, the effects of miR-4262 on cell viability, cell apoptosis, cell autophagy and matrix synthesis were inhibited by SIRT1 (P<0.05). Furthermore, upregulated miR-4262 remarkably increased the expressions of phosphorylated (p)-PI3K, p-AKT and p-mTOR (P<0.05) in TNF-α treated chondrocytes. The present study revealed that the upregulation of miR-4262 may promote the occurrence and development of OA in rats by regulating cell viability, cell apoptosis, cell autophagy, and matrix synthesis. Furthermore, these roles of miR-4262 may be associated with PI3K/AKT/mTOR signaling pathway.
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Affiliation(s)
- Wencai Sun
- Department of Orthopaedics, The Third Hospital Affiliated to Qiqihar Medical College, Qiqihar, Heilongjiang 161006, P.R. China
| | - Yintai Li
- Department of Rehabilitation, Baoji Traditional Chinese Medicine Hospital, Baoji, Shaanxi 721000, P.R. China
| | - Suizhuan Wei
- Department of Orthopaedics, Baoji Traditional Chinese Medicine Hospital, Baoji, Shaanxi 721000, P.R. China
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10
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Kang X, Yang W, Feng D, Jin X, Ma Z, Qian Z, Xie T, Li H, Liu J, Wang R, Li F, Li D, Sun H, Wu S. Cartilage-Specific Autophagy Deficiency Promotes ER Stress and Impairs Chondrogenesis in PERK-ATF4-CHOP-Dependent Manner. J Bone Miner Res 2017; 32:2128-2141. [PMID: 28304100 DOI: 10.1002/jbmr.3134] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/13/2017] [Accepted: 03/15/2017] [Indexed: 01/07/2023]
Abstract
Autophagy is activated during nutritionally depleted or hypoxic conditions to facilitate cell survival. Because growth plate is an avascular and hypoxic tissue, autophagy may have a crucial role during chondrogenesis; however, the functional role and underlying mechanism of autophagy in regulation of growth plate remains elusive. In this study, we generated TamCart Atg7-/- (Atg7cKO) mice to explore the role of autophagy during endochondral ossification. Atg7cKO mice exhibited growth retardation associated with reduced chondrocyte proliferation and differentiation, and increased chondrocyte apoptosis. Meanwhile, we observed that Atg7 ablation mainly induced the PERK-ATF4-CHOP axis of the endoplasmic reticulum (ER) stress response in growth plate chondrocytes. Although Atg7 ablation induced ER stress in growth plate chondrocytes, the addition of phenylbutyric acid (PBA), a chemical chaperone known to attenuate ER stress, partly neutralized such effects of Atg7 ablation on longitudinal bone growth, indicating the causative interaction between autophagy and ER stress in growth plate. Consistent with these findings in vivo, we also observed that Atg7 ablation in cultured chondrocytes resulted in defective autophagy, elevated ER stress, decreased chondrocytes proliferation, impaired expression of col10a1, MMP-13, and VEGFA for chondrocyte differentiation, and increased chondrocyte apoptosis, while such effects were partly nullified by reduction of ER stress with PBA. In addition, Atg7 ablation-mediated impaired chondrocyte function (chondrocyte proliferation, differentiation, and apoptosis) was partly reversed in CHOP-/- cells, indicating the causative role of the PERK-ATF4-CHOP axis of the ER stress response in the action of autophagy deficiency in chondrocytes. In conclusion, our findings indicate that autophagy deficiency may trigger ER stress in growth plate chondrocytes and contribute to growth retardation, thus implicating autophagy as an important regulator during chondrogenesis and providing new insights into the clinical potential of autophagy in cartilage homeostasis. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Xiaomin Kang
- Center for Translational Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Wei Yang
- Center for Translational Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Dongxu Feng
- Center for Translational Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China.,Hong Hui Hospital, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Xinxin Jin
- Center for Translational Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Zhengmin Ma
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Zhuang Qian
- Center for Translational Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Tianping Xie
- Center for Translational Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Huixia Li
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Jiali Liu
- Department of Clinical Laboratory, Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Ruiqi Wang
- Center for Translational Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Fang Li
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Danhui Li
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Hongzhi Sun
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Shufang Wu
- Center for Translational Medicine, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
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11
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Takahashi H, Suzuki Y, Mohamed JS, Gotoh T, Pereira SL, Alway SE. Epigallocatechin-3-gallate increases autophagy signaling in resting and unloaded plantaris muscles but selectively suppresses autophagy protein abundance in reloaded muscles of aged rats. Exp Gerontol 2017; 92:56-66. [PMID: 28286171 PMCID: PMC5501279 DOI: 10.1016/j.exger.2017.02.075] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 01/24/2017] [Accepted: 02/27/2017] [Indexed: 01/26/2023]
Abstract
We have previously found that Epigallocatechin-3-gallate (EGCg), an abundant catechin in green tea, reduced apoptotic signaling and improved muscle recovery in response to reloading after hindlimb suspension (HS). In this study, we investigated if EGCg altered autophagy signaling in skeletal muscle of old rats in response to HS or reloading after HS. Fischer 344×Brown Norway inbred rats (age 34months) were given 1ml/day of purified EGCg (50mg/kg body weight), or the same sample volume of the vehicle by gavage. One group of animals received HS for 14days and the second group of rats received 14days of HS, then the HS was removed and they were allowed to recover by ambulating normally around the cage for two weeks. EGCg decreased a small number of autophagy genes in control muscles, but it increased the expression of other autophagy genes (e.g., ATG16L2, SNCA, TM9SF1, Pink1, PIM-2) and HS did not attenuate these increases. HS increased Beclin1, ATG7 and LC3-II/I protein abundance in hindlimb muscles. Relative to vehicle treatment, EGCg treatment had greater ATG12 protein abundance (35.8%, P<0.05), but decreased Beclin1 protein levels (-101.1%, P<0.05) after HS. However, in reloaded muscles, EGCg suppressed Beclin1 and LC3-II/I protein abundance as compared to vehicle treated muscles. EGCg appeared to "prime" autophagy signaling before and enhance autophagy gene expression and protein levels during unloading in muscles of aged rats, perhaps to improve the clearance of damaged organelles. However, EGCg suppressed autophagy signaling after reloading, potentially to increase the recovery of hindlimb muscles mass and function after loading is restored.
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Affiliation(s)
- Hideyuki Takahashi
- Divison of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Kuju Agricultural Research Center, Graduate School of Agriculture Science, Kyushu University, Naoiri-gun Kuju-cho 4045-4, 878-0201, Oita, Japan
| | - Yutaka Suzuki
- Divison of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Research Faculty of Agriculture, Laboratory of Animal Function and Nutrition, Hokkaido University, Kita-9 Nishi-9, Sapporo, Japan
| | - Junaith S Mohamed
- Divison of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, United States
| | - Takafumi Gotoh
- Kuju Agricultural Research Center, Graduate School of Agriculture Science, Kyushu University, Naoiri-gun Kuju-cho 4045-4, 878-0201, Oita, Japan
| | - Suzette L Pereira
- Discovery Technology, Abbott Nutrition, Columbus, OH 43219, United States
| | - Stephen E Alway
- Divison of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, United States.
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12
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Cell Death in Chondrocytes, Osteoblasts, and Osteocytes. Int J Mol Sci 2016; 17:ijms17122045. [PMID: 27929439 PMCID: PMC5187845 DOI: 10.3390/ijms17122045] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/13/2016] [Accepted: 11/23/2016] [Indexed: 12/04/2022] Open
Abstract
Cell death in skeletal component cells, including chondrocytes, osteoblasts, and osteocytes, plays roles in skeletal development, maintenance, and repair as well as in the pathogenesis of osteoarthritis and osteoporosis. Chondrocyte proliferation, differentiation, and apoptosis are important steps for endochondral ossification. Although the inactivation of P53 and RB is involved in the pathogenesis of osteosarcomas, the deletion of p53 and inactivation of Rb are insufficient to enhance chondrocyte proliferation, indicating the presence of multiple inhibitory mechanisms against sarcomagenesis in chondrocytes. The inflammatory processes induced by mechanical injury and chondrocyte death through the release of danger-associated molecular patterns (DAMPs) are involved in the pathogenesis of posttraumatic osteoarthritis. The overexpression of BCLXL increases bone volume with a normal structure and maintains bone during aging by inhibiting osteoblast apoptosis. p53 inhibits osteoblast proliferation and enhances osteoblast apoptosis, thereby reducing bone formation, but also exerts positive effects on osteoblast differentiation through the Akt–FoxOs pathway. Apoptotic osteocytes release ATP, which induces the receptor activator of nuclear factor κ-B ligand (Rankl) expression and osteoclastogenesis, from pannexin 1 channels. Osteocyte death ultimately results in necrosis; DAMPs are released to the bone surface and promote the production of proinflammatory cytokines, which induce Rankl expression, and osteoclastogenesis is further enhanced.
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13
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Sun H, Cheng D, Ma Y, Wang H, Liang T, Hou G. Autophagy in allografts rejection: A new direction? Biochem Biophys Res Commun 2016; 471:572-5. [PMID: 26876576 DOI: 10.1016/j.bbrc.2016.02.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/09/2016] [Indexed: 02/06/2023]
Abstract
Despite the introduction of new and effective immunosuppressive drugs, acute cellular graft rejection is still a major risk for graft survival. Modulating the dosage of immunosuppressive drugs is not a good choice for all patients, new rejection mechanisms discovery are crucial to limit the inflammatory process and preserve the function of the transplant. Autophagy, a fundamental cellular process, can be detected in all subsets of lymphocytes and freshly isolated naive T lymphocytes. It is required for the homeostasis and function of T lymphocytes, which lead to cell survival or cell death depending on the context. T cell receptor (TCR) stimulation and costimulator signals induce strong autophagy, and autophagy deficient T cells leads to rampant apoptosis upon TCR stimulation. Autophagy has been proved to be activated during ischemia-reperfusion (I/R) injury and associated with grafts dysfunction. Furthermore, Autophagy has also emerged as a key mechanism in orchestrating innate and adaptive immune response to self-antigens, which relates with negative selection and Foxp3(+) Treg induction. Although, the role of autophagy in allograft rejection is unknown, current data suggest that autophagy indeed sweeps across both in the graft organs and recipients lymphocytes after transplantation. This review presents the rationale for the hypothesis that targeting the autophagy pathway could be beneficial in promoting graft survival after transplantation.
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Affiliation(s)
- Hukui Sun
- Nuclear Medicine Departments, Central Hospital of Zibo, Zibo, Shandong, 255036, PR China.
| | - Dayan Cheng
- Nuclear Medicine Departments, Central Hospital of Zibo, Zibo, Shandong, 255036, PR China
| | - Yuanyuan Ma
- Nuclear Medicine Departments, Central Hospital of Zibo, Zibo, Shandong, 255036, PR China
| | - Huaiquan Wang
- Nuclear Medicine Departments, Central Hospital of Zibo, Zibo, Shandong, 255036, PR China
| | - Ting Liang
- Biomedical Isotope Research Center, School of Medicine, Shandong University, Jinan, Shandong, 250012, PR China
| | - Guihua Hou
- Biomedical Isotope Research Center, School of Medicine, Shandong University, Jinan, Shandong, 250012, PR China
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14
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Vuppalapati KK, Bouderlique T, Newton PT, Kaminskyy VO, Wehtje H, Ohlsson C, Zhivotovsky B, Chagin AS. Targeted Deletion of Autophagy Genes Atg5 or Atg7 in the Chondrocytes Promotes Caspase-Dependent Cell Death and Leads to Mild Growth Retardation. J Bone Miner Res 2015; 30:2249-61. [PMID: 26077727 DOI: 10.1002/jbmr.2575] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 06/02/2015] [Accepted: 06/10/2015] [Indexed: 01/06/2023]
Abstract
Longitudinal bone growth takes place in epiphyseal growth plates located in the ends of long bones. The growth plate consists of chondrocytes traversing from the undifferentiated (resting zone) to the terminally differentiated (hypertrophic zone) stage. Autophagy is an intracellular catabolic process of lysosome-dependent recycling of intracellular organelles and protein complexes. Autophagy is activated during nutritionally depleted or hypoxic conditions in order to facilitate cell survival. Chondrocytes in the middle of the growth plate are hypoxic and nutritionally depleted owing to the avascular nature of the growth plate. Accordingly, autophagy may facilitate their survival. To explore the role of autophagy in chondrocyte survival and constitutional bone growth, we generated mice with cartilage-specific ablation of either Atg5 (Atg5cKO) or Atg7 (Atg7cKO) by crossing Atg5 or Atg7 floxed mice with cartilage-specific collagen type 2 promoter-driven Cre. Both Atg5cKO and Atg7cKO mice showed growth retardation associated with enhanced chondrocyte cell death and decreased cell proliferation. Similarly, inhibition of autophagy by Bafilomycin A1 (Baf) or 3-methyladenine (3MA) promoted cell death in cultured slices of human growth plate tissue. To delineate the underlying mechanisms we employed ex vivo cultures of mouse metatarsal bones and RCJ3.IC5.18 rat chondrogenic cell line. Baf or 3MA impaired metatarsal bone growth associated with processing of caspase-3 and massive cell death. Similarly, treatment of RCJ3.IC5.18 chondrogenic cells by Baf also showed massive cell death and caspase-3 cleavage. This was associated with activation of caspase-9 and cytochrome C release. Altogether, our data suggest that autophagy is important for chondrocyte survival, and inhibition of this process leads to stunted growth and caspase-dependent death of chondrocytes.
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Affiliation(s)
- Karuna K Vuppalapati
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Thibault Bouderlique
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Phillip T Newton
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Vitaliy O Kaminskyy
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Henrik Wehtje
- Pediatric Orthopedic Clinic, Karolinska University Hospital, Stockholm, Sweden
| | - Claes Ohlsson
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Boris Zhivotovsky
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Andrei S Chagin
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Wang X, Qi H, Wang Q, Zhu Y, Wang X, Jin M, Tan Q, Huang Q, Xu W, Li X, Kuang L, Tang Y, Du X, Chen D, Chen L. FGFR3/fibroblast growth factor receptor 3 inhibits autophagy through decreasing the ATG12-ATG5 conjugate, leading to the delay of cartilage development in achondroplasia. Autophagy 2015; 11:1998-2013. [PMID: 26491898 PMCID: PMC4824585 DOI: 10.1080/15548627.2015.1091551] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 08/26/2015] [Accepted: 09/03/2015] [Indexed: 01/15/2023] Open
Abstract
FGFR3 (fibroblast growth factor receptor 3) is a negative regulator of endochondral ossification. Gain-of-function mutations in FGFR3 are responsible for achondroplasia, the most common genetic form of dwarfism in humans. Autophagy, an evolutionarily conserved catabolic process, maintains chondrocyte viability in the growth plate under stress conditions, such as hypoxia and nutritional deficiencies. However, the role of autophagy and its underlying molecular mechanisms in achondroplasia remain elusive. In this study, we found activated FGFR3 signaling inhibited autophagic activity in chondrocytes, both in vivo and in vitro. By employing an embryonic bone culture system, we demonstrated that treatment with autophagy inhibitor 3-MA or chloroquine led to cartilage growth retardation, which mimics the effect of activated-FGFR3 signaling on chondrogenesis. Furthermore, we found that FGFR3 interacted with ATG12-ATG5 conjugate by binding to ATG5. More intriguingly, FGFR3 signaling was found to decrease the protein level of ATG12-ATG5 conjugate. Consistently, using in vitro chondrogenic differentiation assay system, we showed that the ATG12-ATG5 conjugate was essential for the viability and differentiation of chondrocytes. Transient transfection of ATG5 partially rescued FGFR3-mediated inhibition on chondrocyte viability and differentiation. Our findings reveal that FGFR3 inhibits the autophagic activity by decreasing the ATG12-ATG5 conjugate level, which may play an essential role in the pathogenesis of achondroplasia.
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Affiliation(s)
- Xiaofeng Wang
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Huabing Qi
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Quan Wang
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Ying Zhu
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Xianxing Wang
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Min Jin
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Qiaoyan Tan
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Qizhao Huang
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Wei Xu
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Xiaogang Li
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Liang Kuang
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Yubing Tang
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Xiaolan Du
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
| | - Di Chen
- Department of Biochemistry; Rush University Medical Center; Chicago, IL USA
| | - Lin Chen
- Center of Bone Metabolism and Repair (CBMR); Trauma Center; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing,China
- State Key Laboratory of Trauma; Burns and Combined Injury; Third Military Medical University; Chongqing, China
- Department of Rehabilitation Medicine; Institute of Surgery Research; Daping Hospital; Third Military Medical University; Chongqing, China
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Abstract
The term "chondropenia" indicates the early stage of degenerative cartilage disease, and it has been identified by carefully monitoring early-stage osteoarthritis (OA). Not only is it the loss of articular cartilage volume, but it is also a rearrangement of biomechanical, ultrastructural, biochemical and molecular properties typical of healthy cartilage tissue. Diagnosing OA at an early stage or an advanced stage is valuable in terms of clinical and therapeutic outcome. In fact degenerative phenomena are supported by a complex biochemical cascade which unbalances the extracellular matrix homeostasis, closely regulated by chondrocytes. In the first stage an intense inflammatory reaction is triggered: pro-catabolic cytokines such as IL-1β and TNF-α triggering matrix metalloproteases and aggrecanase (ADAMT-4 and 5), responsible for the early loss of ultrastructural components, such as type II collagen and aggrecan. In addition nitric oxide and reactive oxygen species modulate the physiopathology of the condral matrix inducing apoptosis of chondrocytes through a mitochondria-dependent pathway. In addition, "Lonely Death": chondrocytes, are confined within a dense, avascular extracellular matrix capsule, and can trigger a genetically induced apoptosis and necrosis. The degenerative process starts from a central point and then spreads in a centrifugal manner in depth and in adjacent areas, eventually covering the whole joint; chondropenia represents a journey from the first clinically detectable time-point until it can be characterized as frank osteoarthritis. Currently, there are no instruments sensitive enough which allow a timely diagnosis of chondropenia. Innovative magnetic resonance imaging techniques, such as T2 mapping, can be effective and a sensitive diagnostic instrument for quantifying cartilage volume and proteoglycan content. However, avant-garde biophysical techniques, such as mechanical indenters, ultrasound and biochemical markers (uCTX-II), are rational and scientific tools applicable to the clinical and therapeutic management of early degenerative cartilage disease. The objective of this review on chondropenia is to present a state of the art and innovative concepts.
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17
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Gruber HE, Hoelscher GL, Ingram JA, Bethea S, Hanley EN. Autophagy in the Degenerating Human Intervertebral Disc: In Vivo Molecular and Morphological Evidence, and Induction of Autophagy in Cultured Annulus Cells Exposed to Proinflammatory Cytokines-Implications for Disc Degeneration. Spine (Phila Pa 1976) 2015; 40:773-82. [PMID: 26091153 DOI: 10.1097/brs.0000000000000865] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Autophagy-related gene expression and ultrastructural features of autophagy were studied in human discs. OBJECTIVE To obtain molecular/morphological data on autophagy in human disc degeneration and cultured human annulus cells exposed to proinflammatory cytokines. SUMMARY OF BACKGROUND DATA Autophagy is an important process by which cytoplasm and organelles are degraded; this adaptive response to sublethal stresses (such as nutrient deprivation present in disc degeneration) supplies needed metabolites. Little is known about autophagic processes during disc degeneration. METHODS Human disc specimens were obtained after institutional review board approval. Annulus mRNA was analyzed to determine autophagy-related gene expression levels. Immunolocalization and ultrastructural studies for p62, ATG3, ATG4B, ATG4C, ATG7, L3A, ULK-2, and beclin were conducted. In vitro experiments used IL-1β- or TNF-α-treated human annulus cells to test for autophagy-related gene expression. RESULTS More degenerated versus healthier discs showed significantly greater upregulation of well-recognized autophagy-related genes (P ≤ 0.028): beclin 1 (upregulated 1.6-fold); ATG8 (LC3) (upregulated 2.0-fold); ATG12 (upregulated 4.0-fold); presenilin 1 (upregulated 1.6-fold); cathepsin B (upregulated 4.5-fold). p62 was localized, and ultrastructure showed autophagic vacuolization and autophagosomes with complex, redundant whorls of membrane-derived material. In vitro, proinflammatory cytokines significantly upregulated autophagy-related genes (P ≤ 0.04): DRAM1 (6.24-fold); p62 (4.98-fold); PIM-2 oncogene, a positive regulator of autophagy (3-fold); WIPI49 (linked to starvation-induced autophagy) (upregulated 2.3-fold). CONCLUSION Data provide initial molecular and morphological evidence for the presence of autophagy in the degenerating human annulus. In vivo gene analyses showed greater autophagy-related gene expression in more degenerated than healthier discs. In vitro data suggested a mechanism implicating a role of TNF-α and IL-1β in disc autophagy. Findings suggest the importance of future work to investigate the relationship of autophagy to apoptosis, cell death, cell senescence, and mitochondrial dysfunction in the aging and degenerating disc. LEVEL OF EVIDENCE N/A.
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Affiliation(s)
- Helen E Gruber
- From the Department of Orthopaedic Surgery, Carolinas HealthCare System, Charlotte, NC
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18
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Xu J, Zhang T, Wang T, You L, Zhao Y. PIM kinases: an overview in tumors and recent advances in pancreatic cancer. Future Oncol 2014; 10:865-76. [PMID: 24799066 DOI: 10.2217/fon.13.229] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The PIM kinases represent a family of serine/threonine kinases, which is composed of three different members (PIM1, PIM2 and PIM3). Aberrant expression of PIM kinases is observed in variety of tumors, including pancreatic cancer. The PIM kinases play pivotal roles in the regulation of cell cycle, apoptosis, properties of stem cells, metabolism, autophagy, drug resistance and targeted therapy. The roles of PIM kinases in pancreatic cancer include the regulation of proliferation, apoptosis, cell cycle, formation, angiogenesis and prediction prognosis. Blocking the activities of PIM kinases could prevent pancreatic cancer development. PIM kinases may be a novel target for cancer therapy.
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Affiliation(s)
- Jianwei Xu
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
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19
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Liu YJ, Zhang L, Papasian CJ, Deng HW. Genome-wide Association Studies for Osteoporosis: A 2013 Update. J Bone Metab 2014; 21:99-116. [PMID: 25006567 PMCID: PMC4075273 DOI: 10.11005/jbm.2014.21.2.99] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 04/30/2014] [Accepted: 04/30/2014] [Indexed: 12/16/2022] Open
Abstract
In the past few years, the bone field has witnessed great advances in genome-wide association studies (GWASs) of osteoporosis, with a number of promising genes identified. In particular, meta-analysis of GWASs, aimed at increasing the power of studies by combining the results from different study populations, have led to the identification of novel associations that would not otherwise have been identified in individual GWASs. Recently, the first whole genome sequencing study for osteoporosis and fractures was published, reporting a novel rare nonsense mutation. This review summarizes the important and representative findings published by December 2013. Comments are made on the notable findings and representative studies for their potential influence and implications on our present understanding of the genetics of osteoporosis. Potential limitations of GWASs and their meta-analyses are evaluated, with an emphasis on understanding the reasons for inconsistent results between different studies and clarification of misinterpretation of GWAS meta-analysis results. Implications and challenges of GWAS are also discussed, including the need for multi- and inter-disciplinary studies.
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Affiliation(s)
- Yong-Jun Liu
- Center for Bioinformatics and Genomics, Department of Biostatistics, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Lei Zhang
- Center for Bioinformatics and Genomics, Department of Biostatistics, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA. ; Center of System Biomedical Sciences, University of Shanghai for Science and Technology, Shanghai, PR, China
| | | | - Hong-Wen Deng
- Center for Bioinformatics and Genomics, Department of Biostatistics, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA. ; Center of System Biomedical Sciences, University of Shanghai for Science and Technology, Shanghai, PR, China
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20
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Downregulation of protein kinase CK2 activity facilitates tumor necrosis factor-α-mediated chondrocyte death through apoptosis and autophagy. PLoS One 2011; 6:e19163. [PMID: 21559479 PMCID: PMC3084779 DOI: 10.1371/journal.pone.0019163] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 03/21/2011] [Indexed: 11/19/2022] Open
Abstract
Despite the numerous studies of protein kinase CK2, little progress has been made in understanding its function in chondrocyte death. Our previous study first demonstrated that CK2 is involved in apoptosis of rat articular chondrocytes. Recent studies have suggested that CK2 downregulation is associated with aging. Thus examining the involvement of CK2 downregulation in chondrocyte death is an urgently required task. We undertook this study to examine whether CK2 downregulation modulates chondrocyte death. We first measured CK2 activity in articular chondrocytes of 6-, 21- and 30-month-old rats. Noticeably, CK2 activity was downregulated in chondrocytes with advancing age. To build an in vitro experimental system for simulating tumor necrosis factor (TNF)-α-induced cell death in aged chondrocytes with decreased CK2 activity, chondrocytes were co-treated with CK2 inhibitors and TNF-α. Viability assay demonstrated that CK2 inhibitors facilitated TNF-α-mediated chondrocyte death. Pulsed-field gel electrophoresis, nuclear staining, flow cytometry, TUNEL staining, confocal microscopy, western blot and transmission electron microscopy were conducted to assess cell death modes. The results of multiple assays showed that this cell death was mediated by apoptosis. Importantly, autophagy was also involved in this process, as supported by the appearance of a punctuate LC3 pattern and autophagic vacuoles. The inhibition of autophagy by silencing of autophage-related genes 5 and 7 as well as by 3-methyladenine treatment protected chondrocytes against cell death and caspase activation, indicating that autophagy led to the induction of apoptosis. Autophagic cells were observed in cartilage obtained from osteoarthritis (OA) model rats and human OA patients. Our findings indicate that CK2 down regulation facilitates TNF-α-mediated chondrocyte death through apoptosis and autophagy. It should be clarified in the future if autophagy observed is a consequence versus a cause of the degeneration in vivo.
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Zhang L, Guo YF, Liu YZ, Liu YJ, Xiong DH, Liu XG, Wang L, Yang TL, Lei SF, Guo Y, Yan H, Pei YF, Zhang F, Papasian CJ, Recker RR, Deng HW. Pathway-based genome-wide association analysis identified the importance of regulation-of-autophagy pathway for ultradistal radius BMD. J Bone Miner Res 2010; 25:1572-80. [PMID: 20200951 PMCID: PMC3153999 DOI: 10.1002/jbmr.36] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Wrist fracture is not only one of the most common osteoporotic fractures but also a predictor of future fractures at other sites. Wrist bone mineral density (BMD) is an important determinant of wrist fracture risk, with high heritability. Specific genes underlying wrist BMD variation are largely unknown. Most published genome-wide association studies (GWASs) have focused only on a few top-ranking single-nucleotide polymorphisms (SNPs)/genes and considered each of the identified SNPs/genes independently. To identify biologic pathways important to wrist BMD variation, we used a novel pathway-based analysis approach in our GWAS of wrist ultradistal radius (UD) BMD, examining approximately 500,000 SNPs genome-wide from 984 unrelated whites. A total of 963 biologic pathways/gene sets were analyzed. We identified the regulation-of-autophagy (ROA) pathway that achieved the most significant result (p = .005, q(fdr) = 0.043, p(fwer) = 0.016) for association with UD BMD. The ROA pathway also showed significant association with arm BMD in the Framingham Heart Study sample containing 2187 subjects, which further confirmed our findings in the discovery cohort. Earlier studies indicated that during endochondral ossification, autophagy occurs prior to apoptosis of hypertrophic chondrocytes, and it also has been shown that some genes in the ROA pathway (e.g., INFG) may play important roles in osteoblastogenesis or osteoclastogenesis. Our study supports the potential role of the ROA pathway in human wrist BMD variation and osteoporosis. Further functional evaluation of this pathway to determine the mechanism by which it regulates wrist BMD should be pursued to provide new insights into the pathogenesis of wrist osteoporosis.
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Affiliation(s)
- Lishu Zhang
- Institute of Bioscience and Biotechnology, School of Science, Beijing Jiaotong University, Beijing, People's Republic of China
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Chondrocyte autophagy is stimulated by HIF-1 dependent AMPK activation and mTOR suppression. Pediatr Nephrol 2010; 25:633-42. [PMID: 19830459 PMCID: PMC2828515 DOI: 10.1007/s00467-009-1310-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 07/28/2009] [Accepted: 08/08/2009] [Indexed: 01/16/2023]
Abstract
The goal of the study is to examine the relationship between the sensor molecules, Hypoxia Inducible Factor-1 (HIF-1), AMP activated Protein Kinase (AMPK) and mammalian Target of Rapamycin (mTOR) in chondrocyte survival and autophagy. We showed that chondrocytes expressed the energy sensor AMPK-1 and that activation increased with maturation. In addition, we showed that thapsigargin treatment activated AMPK and autophagy in a HIF-1-dependent manner. Using serum-starved AMPK-silenced cells, we demonstrated that AMPK was required for the induction of the autophagic response. We also noted a change in chondrocyte sensitivity to apoptogens, due to activation of caspase-8 and cleavage and activation of the pro-apoptotic protein, BID. To test the hypothesis that AMPK signaling directly promoted autophagy, we inhibited AMPK activity in mTOR silenced cells and showed that while mTOR suppression induced autophagy, AMPK inhibition did not block this activity. Based on these findings, it is concluded that because of the micro-environmental changes experienced by the chondrocyte, autophagy is activated by AMPK in a HIF-1-dependent manner.
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Wang Z, Zhang Y, Gu JJ, Davitt C, Reeves R, Magnuson NS. Pim-2 phosphorylation of p21(Cip1/WAF1) enhances its stability and inhibits cell proliferation in HCT116 cells. Int J Biochem Cell Biol 2010; 42:1030-8. [PMID: 20307683 DOI: 10.1016/j.biocel.2010.03.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 02/18/2010] [Accepted: 03/12/2010] [Indexed: 12/19/2022]
Abstract
Pim-2 kinase is one of the three highly conserved Pim family members which are known to be involved in cell survival and cell proliferation. Here we demonstrate that like Pim-1, Pim-2 also phosphorylates the cell cycle inhibitor p21(Cip1/WAF1) (p21) on Thr145 in vitro and in vivo. Overexpression of Pim-2 in HCT116 cells leads to the increased stability of p21 and results in enhanced levels of both exogenous and endogenous p21 proteins. Knockdown of Pim-2 expression via siRNA results in reduced level of endogenous p21, indicating that like Pim-1, Pim-2 is another legitimate p21 kinase. However, Pim-2 has no influence on the nuclear localization of p21 in HCT116 cells. In addition, Pim-2 is able to arrest the cell cycle at G1/S phase and inhibit cell proliferation through phosphorylation of p21 in HCT116 cells. These data suggest that Pim-2 phosphorylation of p21 enhances p21's stability and inhibits cell proliferation in HCT116 cells.
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Affiliation(s)
- Zeping Wang
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164-7520, USA
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Comparative analysis of gene expression profiles between primary knee osteoarthritis and an osteoarthritis endemic to Northwestern China, Kashin-Beck disease. ACTA ACUST UNITED AC 2010; 62:771-80. [DOI: 10.1002/art.27282] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Price J, Zaidi AK, Bohensky J, Srinivas V, Shapiro IM, Ali H. Akt-1 mediates survival of chondrocytes from endoplasmic reticulum-induced stress. J Cell Physiol 2010; 222:502-8. [PMID: 20020442 DOI: 10.1002/jcp.22001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The unfolded protein response (UPR) is an evolutionary conserved adaptive mechanism that permits cells to react and adjust to conditions of endoplasmic reticulum (ER) stress. In addition to UPR, phosphatidylinositol 3-kinase (PI3K)/Akt and extracellular signal regulated kinase (ERK) signaling pathways protect a variety of cells from ER stress. The goal of the present study was to assess the susceptibility of chondrocytes to ER stress and to determine the signaling pathways involved in their survival. We found that low concentration of thapsigargin (10 nM) reduced the viability of a chondrocyte cell line (N1511 cells) and that these cells were approximately 100 fold more susceptible to thapsigargin-induced stress than fibroblasts. Interestingly, in thapsigargin and tunicamycin-stressed chondrocytes induction of the proapoptotic transcription factor CHOP preceded that of the anti-apoptotic BiP by 12 h. Although both of these agents caused sustained Akt and ERK phosphorylation; inhibition of Akt phosphorylation sensitized chondrocytes to ER stress, while blocking ERK signaling by U0126 had no effect. We found that Akt-1, but not Akt-2 or Akt-3, is predominantly expressed in N1511 chondrocytes. Furthermore, siRNA-mediated knockdown of Akt-1 sensitized chondrocytes to ER stress, which was associated with increased capsase-3 activity and decreased Bcl(XL) expression. These data suggest that under condition of ER stress, multiple signaling processes regulate chondrocyte's survival-death decisions. Thus, rapid upregulation of CHOP likely contributes to chondrocyte death, while Akt-1-mediated inactivation of caspase 3 and induction of BclXL promotes survival.
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Affiliation(s)
- Jeremy Price
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania 19104, USA
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Bohensky J, Leshinsky S, Srinivas V, Shapiro IM. Chondrocyte autophagy is stimulated by HIF-1 dependent AMPK activation and mTOR suppression. Carcinogenesis 2009; 32:545-53. [PMID: 19830459 DOI: 10.1093/carcin/bgr001] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The goal of the study is to examine the relationship between the sensor molecules, Hypoxia Inducible Factor-1 (HIF-1), AMP activated Protein Kinase (AMPK) and mammalian Target of Rapamycin (mTOR) in chondrocyte survival and autophagy. We showed that chondrocytes expressed the energy sensor AMPK-1 and that activation increased with maturation. In addition, we showed that thapsigargin treatment activated AMPK and autophagy in a HIF-1-dependent manner. Using serum-starved AMPK-silenced cells, we demonstrated that AMPK was required for the induction of the autophagic response. We also noted a change in chondrocyte sensitivity to apoptogens, due to activation of caspase-8 and cleavage and activation of the pro-apoptotic protein, BID. To test the hypothesis that AMPK signaling directly promoted autophagy, we inhibited AMPK activity in mTOR silenced cells and showed that while mTOR suppression induced autophagy, AMPK inhibition did not block this activity. Based on these findings, it is concluded that because of the micro-environmental changes experienced by the chondrocyte, autophagy is activated by AMPK in a HIF-1-dependent manner.
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Affiliation(s)
- Jolene Bohensky
- Department of Orthopedic Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Bohensky J, Terkhorn SP, Freeman TA, Adams CS, Garcia JA, Shapiro IM, Srinivas V. Regulation of autophagy in human and murine cartilage: hypoxia-inducible factor 2 suppresses chondrocyte autophagy. ACTA ACUST UNITED AC 2009; 60:1406-15. [PMID: 19404942 DOI: 10.1002/art.24444] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We have previously demonstrated that the transcription factor hypoxia-inducible factor 1 (HIF-1) promotes the onset of autophagy in chondrocytes. The overall goal of this study was to test the hypothesis that another HIF family transcription factor, HIF-2, modulates the induction of autophagy by chondrocytes. METHODS Expression of HIF-1, HIF-2, and light chain 3 (LC3) in human and murine articular cartilage was visualized by immunohistochemistry. Suppression of HIF-2 was achieved using small interfering RNA technology. Assessments of autophagic flux and lysosomal activity, as well as ultrastructural analysis, were performed in chondrocytes in cell culture. RESULTS HIF-2 was expressed abundantly by cells in human and murine articular cartilage and in the cartilage of mineralizing vertebrae from neonatal mice. Protein levels were reduced in articular cartilage from older mice, in end-plate cartilage from mice, and in chondrocytes from human osteoarthritic (OA) cartilage. HIF-2 was robustly expressed in the prehypertrophic cells of mouse growth cartilage. When HIF-2alpha was silenced, the generation of reactive oxygen species was found to be elevated, with a concomitant decrease in catalase and superoxide dismutase activity. Suppression of HIF-2 was associated with decreased Akt-1 and mammalian target of rapamycin activities, reduced Bcl-xL expression, and a robust autophagic response, even under nutrient-replete conditions. In these silenced chondrocytes, HIF-1 expression was elevated. Decreased HIF-2 expression was associated with autophagy in OA tissues and aging cartilage samples. The autophagic response of chondrocytes in HIF-2alpha-knockout mouse growth plate showed an elevated autophagic response throughout the plate. CONCLUSION Based on these observations, we conclude that HIF-2 is a potent regulator of autophagy in maturing chondrocytes. Our data suggest that this protein acts as a brake on the autophagy-accelerator function of HIF-1.
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Affiliation(s)
- Jolene Bohensky
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Guo R, Zhong L, Ren J. Overexpression of aldehyde dehydrogenase-2 attenuates chronic alcohol exposure-induced apoptosis, change in Akt and Pim signalling in liver. Clin Exp Pharmacol Physiol 2009; 36:463-8. [PMID: 19215238 DOI: 10.1111/j.1440-1681.2009.05152.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
1. The liver, the main site of ethanol oxidation, is extremely vulnerable to the toxic effects of alcohol. Chronic alcohol intake has been shown to result in alcoholic liver disease, although the precise mechanism of action remains poorly understood. 2. The present study was designed to examine the impact of facilitated acetaldehyde metabolism via overexpression of aldehyde dehydrogenase-2 (ALDH2) on chronic alcohol ingestion-induced hepatic damage. Mice (wild-type Friend Virus B (FVB) and ALDH2 transgenic mice) were placed on a 4% alcohol or control diet for 12 weeks. Pro- and anti-apoptotic proteins, including p53, Omi/HtrA2, Bcl-2, Bax, X-linked inhibitor of apoptosis protein (XIAP), Akt, phosphorylated (p) Akt, the Akt downstream signalling molecule Pim and pPim, were examined using immunoblot analysis. Apoptosis and protein damage were assessed using the caspase 3 assay and protein carbonyl formation, respectively. 3. The data revealed that alcohol intake enhanced expression of p53, Omi/HtrA2, Bcl-2 and Bax without affecting XIAP expression or the Bcl-2/Bax ratio. Total Akt and pPim were downregulated in response to alcohol, whereas total Pim was upregulated in conjunction with unchanged pAkt. As a result, the pAkt : Akt and pPim : Pim ratios were elevated and reduced, respectively, in response to alcohol. All these effects that resulted from alcohol exposure were attenuated or ablated by ALDH2. 4. Collectively, the results suggest that ALDH2 may effectively ameliorate alcohol-induced hepatic apoptosis and changes in Akt as well as Pim signalling.
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Affiliation(s)
- Rui Guo
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming School of Pharmacy, Laramie, WY 82071, USA
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Srinivas V, Bohensky J, Shapiro IM. Autophagy: a new phase in the maturation of growth plate chondrocytes is regulated by HIF, mTOR and AMP kinase. Cells Tissues Organs 2008; 189:88-92. [PMID: 18703865 DOI: 10.1159/000151428] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The overall goal of the investigation was to examine autophagy in the growth plate and to ascertain how this process was regulated. Herein, we show that in the postmitotic maturing zone of the growth plate, chondrocytes express an autophagic phenotype. This robust and particulate immunohistochemical response provides direct evidence that autophagy is a new and transient stage in the chondrocyte maturation pathway. We found that induction of autophagy was regulated by mTOR, a sensor of cellular metabolism. When mTOR was inhibited, changes in LC3 fluorescence indicated that this kinase regulated development of the autophagic state. To determine if AMP kinase was required for chondrocyte autophagy, we suppressed its expression in N1511 cells using siRNA technology. When these cells were serum starved, a condition that triggers autophagy, there was no change in LC3 distribution. This result confirmed that AMP kinase was required for the induction of the autophagic response. Based on the 2 studies described above, and our previous observation that HIF-1 is required for the induction of autophagy, we put forward the hypothesis that autophagy is regulated by the activities of AMP kinase and mTOR in a HIF-1-dependent manner. Once autophagy is activated, the postmitotic chondrocytes would be expected to remain viable in their unique microenvironment and complete their life cycle.
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Affiliation(s)
- Vickram Srinivas
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pa. 19107, USA
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Watanabe H, Bohensky J, Freeman T, Srinivas V, Shapiro IM. Hypoxic induction of UCP3 in the growth plate: UCP3 suppresses chondrocyte autophagy. J Cell Physiol 2008; 216:419-25. [PMID: 18288636 DOI: 10.1002/jcp.21408] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The overall goal of the investigation was to examine the role of uncoupling proteins (UCPs) in regulating late stage events in the chondrocyte maturation pathway. We showed for the first time that epiphyseal chondrocytes expressed UCP3. In hypoxia, UCP3 mediated regulation of the mitochondrial transmembrane potential (DeltaPsi(m)) was dependent on HIF-1alpha. We also showed for the first time that UCP3 regulated the induction of autophagy. Thus, suppression of UCP3 enhanced the expression of the autophagic phenotype, even in serum-replete media. Predictably, the mature autophagic chondrocytes were susceptible to an apoptogen challenge. Susceptibility was probably associated with a lowered expression of the anti-apoptotic proteins Bcl2 and BCL(xL) and a raised baseline expression of cytochrome c in the cytosol. These changes would serve to promote sensitivity to apoptogens. We conclude that in concert with HIF-1alpha, UCP3 regulates the activity of the mitochondrion by modulating the transmembrane potential. In addition, it inhibits induction of the autophagic response. When this occurs, it suppresses sensitivity to agents that promote chondrocyte deletion from the growth plate.
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Affiliation(s)
- Hitoshi Watanabe
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Abstract
To date, most studies examining cell death during the development of osteoarthritis (OA) have focused on death of chondrocytes and have primarily examined advanced stages of the disease. Very good evidence suggests that chondrocyte death does occur at some point in the pathogenesis of OA and that it can be due to apoptosis, necrosis, or some combination of the two. Chondrocyte death can be induced by mechanical injury, loss of extracellular matrix, loss of growth factors, or excessive levels of reactive oxygen species. Although therapy specifically targeting cell death in human OA has not been reported, preclinical studies in animal models have provided early evidence that inhibition of caspases might slow OA-like changes in articular cartilage. Because of potential unwanted side effects from agents systemically inhibiting cell death, treatments specifically targeting cell death in OA will likely need to be delivered locally and in a manner that prevents systemic absorption. Inhibition of cell death in OA likely will not be a sole therapeutic target but rather a desired effect of interventions designed to reverse the catabolic-anabolic imbalance occurring in OA joint tissues.
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Phornphutkul C, Wu KY, Auyeung V, Chen Q, Gruppuso PA. mTOR signaling contributes to chondrocyte differentiation. Dev Dyn 2008; 237:702-12. [PMID: 18265001 DOI: 10.1002/dvdy.21464] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The mammalian Target Of Rapamycin (mTOR) is a nutrient-sensing protein kinase that regulates numerous cellular processes. Fetal rat metatarsal explants were used as a physiological model to study the effect of mTOR inhibition on chondrogenesis. Insulin significantly enhanced their growth. Rapamycin significantly diminished this response to insulin through a selective effect on the hypertrophic zone. Cell proliferation (bromodeoxyuridine incorporation) was unaffected by rapamycin. Similar observations were made when rapamycin was injected to embryonic day (E) 19 fetal rats in situ. In the ATDC5 chondrogenic cell line, rapamycin inhibited proteoglycan accumulation and collagen X expression. Rapamycin decreased content of Indian Hedgehog (Ihh), a regulator of chondrocyte differentiation. Addition of Ihh to culture medium reversed the effect of rapamycin. We conclude that modulation of mTOR signaling contributes to chondrocyte differentiation, perhaps through its ability to regulate Ihh. Our findings support the hypothesis that nutrients, acting through mTOR, directly influence chondrocyte differentiation and long bone growth.
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Affiliation(s)
- Chanika Phornphutkul
- Department of Pediatrics, Division of Pediatric Endocrinology and Metabolism, Rhode Island Hospital and Brown University, Providence, Rhode Island 02903, USA.
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