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Bianchi L, Damiani I, Castiglioni S, Carleo A, De Salvo R, Rossi C, Corsini A, Bellosta S. Smooth Muscle Cell Phenotypic Switch Induced by Traditional Cigarette Smoke Condensate: A Holistic Overview. Int J Mol Sci 2023; 24:ijms24076431. [PMID: 37047404 PMCID: PMC10094728 DOI: 10.3390/ijms24076431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/19/2023] [Accepted: 03/25/2023] [Indexed: 04/01/2023] Open
Abstract
Cigarette smoke (CS) is a risk factor for inflammatory diseases, such as atherosclerosis. CS condensate (CSC) contains lipophilic components that may represent a systemic cardiac risk factor. To better understand CSC effects, we incubated mouse and human aortic smooth muscle cells (SMCs) with CSC. We evaluated specific markers for contractile [i.e., actin, aortic smooth muscle (ACTA2), calponin-1 (CNN1), the Kruppel-like factor 4 (KLF4), and myocardin (MYOCD) genes] and inflammatory [i.e., IL-1β, and IL-6, IL-8, and galectin-3 (LGALS-3) genes] phenotypes. CSC increased the expression of inflammatory markers and reduced the contractile ones in both cell types, with KLF4 modulating the SMC phenotypic switch. Next, we performed a mass spectrometry-based differential proteomic approach on human SMCs and could show 11 proteins were significantly affected by exposition to CSC (FC ≥ 2.7, p ≤ 0.05). These proteins are active in signaling pathways related to expression of pro-inflammatory cytokines and IFN, inflammasome assembly and activation, cytoskeleton regulation and SMC contraction, mitochondrial integrity and cellular response to oxidative stress, proteostasis control via ubiquitination, and cell proliferation and epithelial-to-mesenchymal transition. Through specific bioinformatics resources, we showed their tight functional correlation in a close interaction niche mainly orchestrated by the interferon-induced double-stranded RNA-activated protein kinase (alternative name: protein kinase RNA-activated; PKR) (EIF2AK2/PKR). Finally, by combining gene expression and protein abundance data we obtained a hybrid network showing reciprocal integration of the CSC-deregulated factors and indicating KLF4 and PKR as the most relevant factors.
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Interferon-gamma modulates articular chondrocyte and osteoblast metabolism through protein kinase R-independent and dependent mechanisms. Biochem Biophys Rep 2022; 32:101323. [PMID: 36105611 PMCID: PMC9464860 DOI: 10.1016/j.bbrep.2022.101323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/20/2022] [Accepted: 08/01/2022] [Indexed: 11/23/2022] Open
Abstract
Osteoarthritis (OA) affects multiple tissues of the synovial joint and is characterised by articular cartilage degeneration and bone remodelling. Interferon-γ (IFN-γ) is implicated in osteoarthritis pathology exerting its biological effects via various mechanisms including activation of protein kinase R (PKR), which has been implicated in inflammation and arthritis. This study investigated whether treatment of articular cartilage chondrocytes and osteoblasts with IFN-γ could induce a degradative phenotype that was mediated through the PKR signalling pathway. IFN-γ treatment of chondrocytes increased transcription of key inflammatory mediators (TNF-α, IL-6), matrix degrading enzymes (MMP-13), the transcription factor STAT1, and PKR. Activation of PKR was involved in the regulation of TNF-α, IL-6, and STAT1. In osteoblasts, IFN-γ increased human and mouse STAT1, and human IL-6 through a mechanism involving PKR. ALP, COL1A1 (human and mouse), RUNX2 (mouse), and PHOSPHO1 (mouse) were decreased by IFN-γ. The number of PKR positive cells were increased in post-traumatic OA (PTOA). This study has revealed that IFN-γ propagates inflammatory and degenerative events in articular chondrocytes and osteoblasts via PKR activation. Since IFN-γ and PKR signalling are both activated in early PTOA, these mechanisms are likely to contribute to joint degeneration after injury and might offer attractive targets for therapeutic intervention. •IFN-γ treatment of chondrocytes increased transcription of TNF-α, IL-6, and STAT1 via PKR activation. •In osteoblasts, IFN-γ increased STAT1 and IL-6 via PKR activation. •The number of PKR positive cells were increased in post-traumatic OA (PTOA). •IFN-γ propagates inflammatory and degenerative events in articular chondrocytes and osteoblasts via PKR activation. •IFN-γ and PKR signalling are both activated in early PTOA and are likely to contribute to joint degeneration after injury.
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Yang M, Gu J, Xu F, Wang Y, Wang H, Zhang B. The protective role of glucocerebrosidase/ceramide in rheumatoid arthritis. Connect Tissue Res 2022; 63:625-633. [PMID: 35313755 DOI: 10.1080/03008207.2022.2055552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To clarify the role of glucocerebrosidase (GBA) and Ceramide (Cer) in rheumatoid arthritis (RA). METHODS GBA-expressing lentivirus were constructed and injected into collagen-induced arthritis (CIA) mice, and compared with CIA mice injected with empty vector. The severity of arthritis and inflammatory mediators were evaluated. Fibroblast-like synoviocytes (FLS) from RA patients were transfected with GBA-expressing lentivirus, or pretreated with C6-Cer. The migration and invasion of FLS, the production of inflammatory cytokines, and the relevant signaling pathways were assessed. RESULTS In CIA mice, GBA markedly improved arthritis compared to that in the CIA mice, with increased content of proteoglycan and integral cartilage surfaces and tidemarks. The circulating inflammatory mediators, including interleukin (IL)-1β, IL-6, IL-18, and matrix metalloproteinase (MMP)-1, were significantly reduced in CIA mice with GBA overexpression compared to those in CIA mice. GBA and C6-Cer treatment inhibited migration and invasion of FLS, and suppressed production of inflammatory cytokines and activation of the MAPK pathways. CONCLUSION GBA/Cer exhibited a protective role in CIA mice and RA FLS. These results highlight the potential of targeting GBA/Cer as a therapeutic strategy in RA and warrant further investigation.
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Affiliation(s)
- Mingfeng Yang
- Department of Rheumatology and Immunology, The Affiliated Hospital of Jiaxing University (The First Hospital of Jiaxing), Jiaxing, Zhejiang, China
| | - Juanfang Gu
- Department of Rheumatology and Immunology, The Affiliated Hospital of Jiaxing University (The First Hospital of Jiaxing), Jiaxing, Zhejiang, China
| | - Fangyan Xu
- Department of Rheumatology and Immunology, The Affiliated Hospital of Jiaxing University (The First Hospital of Jiaxing), Jiaxing, Zhejiang, China
| | - Yiwen Wang
- Department of Rheumatology and Immunology, The Affiliated Hospital of Jiaxing University (The First Hospital of Jiaxing), Jiaxing, Zhejiang, China
| | - Hongzhi Wang
- Department of Rheumatology and Immunology, The Affiliated Hospital of Jiaxing University (The First Hospital of Jiaxing), Jiaxing, Zhejiang, China
| | - Bin Zhang
- Department of Rheumatology and Immunology, The Affiliated Hospital of Jiaxing University (The First Hospital of Jiaxing), Jiaxing, Zhejiang, China
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Kim S, Lee K, Choi YS, Ku J, Kim H, Kharbash R, Yoon J, Lee YS, Kim JH, Lee YJ, Kim Y. Mitochondrial double-stranded RNAs govern the stress response in chondrocytes to promote osteoarthritis development. Cell Rep 2022; 40:111178. [PMID: 35947956 DOI: 10.1016/j.celrep.2022.111178] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 05/13/2022] [Accepted: 07/19/2022] [Indexed: 11/28/2022] Open
Abstract
Protein kinase R (PKR) is an immune response protein that becomes activated by double-stranded RNAs (dsRNAs). PKR overactivation is associated with degenerative diseases with inflammation, including osteoarthritis (OA), but the dsRNA activator remains largely unknown. Here, we find that mitochondrial dsRNA (mt-dsRNA) expression and its cytosolic efflux are facilitated in chondrocytes under OA-eliciting conditions, leading to innate immune activation. Moreover, mt-dsRNAs are released to the extracellular space and activate Toll-like receptor 3 at the plasma membrane. Elevated levels of mt-dsRNAs in the synovial fluids and damaged cartilage of OA patients and in the cartilage of surgery-induced OA mice further support our data. Importantly, autophagy prevents PKR activation and protects chondrocytes from mitochondrial stress partly by removing cytosolic mtRNAs. Our study provides a comprehensive understanding of innate immune activation by mt-dsRNAs during stress responses that underlie the development of OA and suggests mt-dsRNAs as a potential target for chondroprotective intervention.
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Affiliation(s)
- Sujin Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Keonyong Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Yong Seok Choi
- Medical Science Research Institute, Seoul National University Bundang Hospital, Seongnam 13605, South Korea
| | - Jayoung Ku
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Hyeonkyeong Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, South Korea; Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Raisa Kharbash
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Jimin Yoon
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Yong Seuk Lee
- Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13605, South Korea
| | - Jin-Hong Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, South Korea; Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea; Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 08826, South Korea
| | - Yun Jong Lee
- Division of Rheumatology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13605, South Korea; Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, South Korea.
| | - Yoosik Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea; KAIST Institute for Health Science and Technology (KIHST), KAIST, Daejeon 34141, South Korea; KAIST Institute for BioCentury, KAIST, Daejeon 34141, South Korea; BioProcess Engineering Research Center and BioInformatics Research Center, KAIST, Daejeon 34141, South Korea.
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Ozkan E, Bakar-Ates F. The Trinity of Matrix Metalloproteinases, Inflammation, and Cancer: A Literature Review of Recent Updates. Antiinflamm Antiallergy Agents Med Chem 2021; 19:206-221. [PMID: 32178620 PMCID: PMC7499348 DOI: 10.2174/1871523018666191023141807] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/02/2019] [Accepted: 10/10/2019] [Indexed: 12/12/2022]
Abstract
The critical link between cancer and inflammation has been known for many years. This complex network was further complexed by revealing the association of the matrix metalloproteinase family members with inflammatory cytokines, which were previously known to be responsible for the development of metastasis. This article summarizes the current studies which evaluate the relationship between cancer and inflammatory microenvironment as well as the roles of MMPs on invasion and metastasis together.
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Affiliation(s)
- Erva Ozkan
- Department of Biochemistry, Faculty of Pharmacy, Ankara University, Ankara, Turkey
| | - Filiz Bakar-Ates
- Department of Biochemistry, Faculty of Pharmacy, Ankara University, Ankara, Turkey
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6
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Chen Y, Shen J. Mucosal immunity and tRNA, tRF, and tiRNA. J Mol Med (Berl) 2020; 99:47-56. [PMID: 33200232 DOI: 10.1007/s00109-020-02008-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/15/2020] [Accepted: 11/06/2020] [Indexed: 12/13/2022]
Abstract
Mucosal immunity has crucial roles in human diseases such as respiratory tract infection, inflammatory bowel diseases (IBD), and colorectal cancer (CRC). Recent studies suggest that the mononuclear phagocyte system, cancer cells, bacteria, and viruses induce the mucosal immune reaction by various pathways, and can be major factors in the pathogenesis of these diseases. Transfer RNA (tRNA) and its fragments, including tRNA-derived RNA fragments (tRFs) and tRNA-derived stress-induced RNAs (tiRNAs), have emerged as a hot topic in recent years. They not only are verified as essential for transcription and translation but also play roles in cellular homeostasis and functions, such as cell metastasis, proliferation, and apoptosis. However, the specific relationship between their biological regulation and mucosal immunity remains unclear to date. In the present review, we carry out a comprehensive discussion on the specific roles of tRNA, tRFs, and tiRNAs relevant to mucosal immunity and related diseases.
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Affiliation(s)
- Yueying Chen
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Inflammatory Bowel Disease Research Center, 160# Pu Jian Ave, Shanghai, 200127, China
- Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160# Pu Jian Ave, Shanghai, 200127, China
- Shanghai Institute of Digestive Disease, 160# Pu Jian Ave, Shanghai, 200127, China
| | - Jun Shen
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Inflammatory Bowel Disease Research Center, 160# Pu Jian Ave, Shanghai, 200127, China.
- Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160# Pu Jian Ave, Shanghai, 200127, China.
- Shanghai Institute of Digestive Disease, 160# Pu Jian Ave, Shanghai, 200127, China.
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PKR Promotes Oxidative Stress and Apoptosis of Human Articular Chondrocytes by Causing Mitochondrial Dysfunction through p38 MAPK Activation-PKR Activation Causes Apoptosis in Human Chondrocytes. ANTIOXIDANTS (BASEL, SWITZERLAND) 2019. [PMID: 31484360 DOI: 10.3390/antiox8090370.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Osteoarthritis (OA) is one of the most common types of arthritis in the elderly people. It has been known that chondrocyte apoptosis occurs in OA cartilage; however, the detailed molecular mechanism remains unclear. In the current study, we aimed to elucidate the role of double-stranded RNA-dependent protein kinase R (PKR) in the TNF-α-caused apoptosis in chondrocytes. Human articular chondrocytes were digested from cartilages of OA subjects who accepted arthroplastic knee surgery. Our results showed that phosphorylation of p38 MAPK was increased after TNF-α stimulation or PKR activation using poly (I:C), and TNF-α-induced p38 MAPK upregulation was inhibited by PKR inhibition, suggesting phosphor-p38 MAPK was regulated by PKR. Moreover, we found that PKR participated in the p53-dependent destruction of AKT following activation of p38 MAPK. The inhibition of AKT led to the reduced expression of PGC-1α, which resulted in mitochondrial dysfunction and increased oxidative stress. We showed that the reduction of oxidative stress using antioxidant Mito TEMPO lowered the TNF-α-induced caspase-3 activation and TUNEL-positive apoptotic cells. The diminished apoptotic response was also observed after repression of PKR/p38 MAPK/p53/AKT/PGC-1α signaling. Taken together, we demonstrated that the aberrant mitochondrial biogenesis and increased oxidative stress in chondrocytes after TNF-α stimulation were mediated by PKR, which may contribute to the chondrocyte apoptosis and cartilage degeneration in OA.
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PKR Promotes Oxidative Stress and Apoptosis of Human Articular Chondrocytes by Causing Mitochondrial Dysfunction through p38 MAPK Activation-PKR Activation Causes Apoptosis in Human Chondrocytes. Antioxidants (Basel) 2019; 8:antiox8090370. [PMID: 31484360 PMCID: PMC6769915 DOI: 10.3390/antiox8090370] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/14/2019] [Accepted: 08/28/2019] [Indexed: 12/15/2022] Open
Abstract
Osteoarthritis (OA) is one of the most common types of arthritis in the elderly people. It has been known that chondrocyte apoptosis occurs in OA cartilage; however, the detailed molecular mechanism remains unclear. In the current study, we aimed to elucidate the role of double-stranded RNA-dependent protein kinase R (PKR) in the TNF-α-caused apoptosis in chondrocytes. Human articular chondrocytes were digested from cartilages of OA subjects who accepted arthroplastic knee surgery. Our results showed that phosphorylation of p38 MAPK was increased after TNF-α stimulation or PKR activation using poly (I:C), and TNF-α-induced p38 MAPK upregulation was inhibited by PKR inhibition, suggesting phosphor-p38 MAPK was regulated by PKR. Moreover, we found that PKR participated in the p53-dependent destruction of AKT following activation of p38 MAPK. The inhibition of AKT led to the reduced expression of PGC-1α, which resulted in mitochondrial dysfunction and increased oxidative stress. We showed that the reduction of oxidative stress using antioxidant Mito TEMPO lowered the TNF-α-induced caspase-3 activation and TUNEL-positive apoptotic cells. The diminished apoptotic response was also observed after repression of PKR/p38 MAPK/p53/AKT/PGC-1α signaling. Taken together, we demonstrated that the aberrant mitochondrial biogenesis and increased oxidative stress in chondrocytes after TNF-α stimulation were mediated by PKR, which may contribute to the chondrocyte apoptosis and cartilage degeneration in OA.
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9
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Piazzi M, Bavelloni A, Greco S, Focaccia E, Orsini A, Benini S, Gambarotti M, Faenza I, Blalock WL. Expression of the double-stranded RNA-dependent kinase PKR influences osteosarcoma attachment independent growth, migration, and invasion. J Cell Physiol 2019; 235:1103-1119. [PMID: 31240713 DOI: 10.1002/jcp.29024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 06/04/2019] [Indexed: 12/15/2022]
Abstract
Osteosarcoma (OS) is a rare, insidious tumor of mesenchymal origin that most often affects children, adolescents, and young adults. While the primary tumor can be controlled with chemotherapy and surgery, it is the lung metastases that are eventually fatal. Multiple studies into the initial drivers of OS development have been undertaken, but few of these have examined innate immune/inflammatory signaling. A central figure in inflammatory signaling is the innate immune/stress-activated kinase double-stranded RNA-dependent protein kinase (PKR). To characterize the role of PKR in OS, U2OS, and SaOS-2 osteosarcoma cell lines were stably transfected with wild-type or dominant-negative (DN) PKR. Overexpression of PKR enhanced colony formation in soft agar (U2OS and SaOS-2), enhanced cellular migration (U2OS), and invasive migration (SaOS-2). In contrast, overexpression of DN-PKR inhibited attachment-independent growth, migration and/or invasion. These data demonstrate a role for inflammatory signaling in OS formation and migration/invasion and suggest the status of PKR expression/activation may have prognostic value.
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Affiliation(s)
- Manuela Piazzi
- Istituto di Genetica Molecolare-Luigi Luca Cavalli Sforza, UOS Bologna, Consiglio Nazionale Delle Ricerche (IGM-CNR), Bologna, Italy.,IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
| | | | - Sara Greco
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - Enrico Focaccia
- Istituto di Genetica Molecolare-Luigi Luca Cavalli Sforza, UOS Bologna, Consiglio Nazionale Delle Ricerche (IGM-CNR), Bologna, Italy
| | - Arianna Orsini
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | | | | | - Irene Faenza
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - William L Blalock
- Istituto di Genetica Molecolare-Luigi Luca Cavalli Sforza, UOS Bologna, Consiglio Nazionale Delle Ricerche (IGM-CNR), Bologna, Italy.,IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
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10
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Kim S, Ku Y, Ku J, Kim Y. Evidence of Aberrant Immune Response by Endogenous Double-Stranded RNAs: Attack from Within. Bioessays 2019; 41:e1900023. [PMID: 31099409 DOI: 10.1002/bies.201900023] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/15/2019] [Indexed: 12/17/2022]
Abstract
Many innate immune response proteins recognize foreign nucleic acids from invading pathogens to initiate antiviral signaling. These proteins mostly rely on structural characteristics of the nucleic acids rather than their specific sequences to distinguish self and nonself. One feature utilized by RNA sensors is the extended stretch of double-stranded RNA (dsRNA) base pairs. However, the criteria for recognizing nonself dsRNAs are rather lenient, and hairpin structure of self-RNAs can also trigger an immune response. Consequently, aberrant activation of RNA sensors has been reported in numerous human diseases. Yet, in most cases, the activating antigens remain unknown. Recent studies have developed sequencing techniques tailored to specifically capture dsRNAs and identified that various noncoding elements in the nuclear and the mitochondrial genome can generate dsRNAs. Here, the identity of endogenous dsRNAs, their recognition by dsRNA sensors, and their implications in the pathogenesis of human diseases ranging from inflammatory to degenerative are presented.
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Affiliation(s)
- Sujin Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yongsuk Ku
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jayoung Ku
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yoosik Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
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11
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Drevet S, Gavazzi G, Grange L, Dupuy C, Lardy B. Reactive oxygen species and NADPH oxidase 4 involvement in osteoarthritis. Exp Gerontol 2018; 111:107-117. [PMID: 30012342 DOI: 10.1016/j.exger.2018.07.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 01/04/2023]
Abstract
Osteoarthritis (OA) is a degenerative chronic disease affecting >300,000 million people around the world as of 2016. Symptomatic measures exist, but there are hardly any curative treatments available. Disruption of the cartilage homeostasis in favor of catabolism leads to cartilage destruction. ROS-macromolecular-induced damage is significantly greater in OA cartilage and OA is described as low-grade chronic systemic inflammation. This review aimed to assess the critical role of cartilage ageing and oxidative stress in the OA process, focusing in particular on NADPH oxidase and especially Nox4 involvement. With age, hypertrophic senescent cells with an altered redox cell profile accumulated. Chondrocytes are more sensitive to oxidant-mediators and the serum level of pro-inflammatory mediators increases. Age-related advanced glycation end products impact on extra cellular matrix (ECM) properties leading to the apoptosis of chondrocytes. A focus on NADPH oxidase-mediated-ROS signaling highlighted the very specific Nox4 isoform, which plays a role on the final common pathway targeting chondrocyte cells. IL-1β-mediated Nox4 stimulation induced an increase in the levels released by the chondrocyte of MMP-1 and MMP-13 proteins, which are involved in ECM degradation. In comparison with the other Nox isoforms, Nox4 remains unusual, since it is constitutively active, does not depend on cytosolic activator proteins and seems to generate H2O2 thanks to the specific conformation of the Nox4 E-loop. Nox4-induced ROS production appears an essential actor in the OA process and it could be relevant to focus on this target in the aim of discovering and developing new therapeutic strategies.
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Affiliation(s)
- S Drevet
- Grenoble Alpes University Hospital, Orthogeriatric Unit, Geriatric Department, Grenoble Alpes University, GREPI UGA-EFS EA7408, Boulevard de la Chantourne, 38043 Grenoble Cedex 1, France.
| | - G Gavazzi
- Grenoble Alpes University Hospital, Acute Geriatric Medicine Unit, Geriatric Department, Grenoble Alpes University, GREPI UGA-EFS EA7408, Boulevard de la Chantourne, 38043 Grenoble Cedex 1, France.
| | - L Grange
- Grenoble Alpes University Hospital, Rheumatology Department, Hopital Sud, GREPI UGA-EFS EA7408, 19 avenue de Kimberley, 38130 Echirolles, France.
| | - C Dupuy
- Institut Gustave Roussy, UMR 8200 CNRS "Stabilité génétique et Oncogenèse", 114 rue Edouard Vaillant, 94805 Villejuif Cedex, France.
| | - B Lardy
- Grenoble Alpes University Hospital, Biology Department, Grenoble Alpes University, GREPI UGA-EFS EA7408, Boulevard de la Chantourne, 38043 Grenoble Cedex 1, France.
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Ma CH, Wu CH, Jou IM, Tu YK, Hung CH, Hsieh PL, Tsai KL. PKR activation causes inflammation and MMP-13 secretion in human degenerated articular chondrocytes. Redox Biol 2017; 14:72-81. [PMID: 28869834 PMCID: PMC5582648 DOI: 10.1016/j.redox.2017.08.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 07/31/2017] [Accepted: 08/15/2017] [Indexed: 01/04/2023] Open
Abstract
Osteoarthritis (OA) is a degenerative joint disease affecting a large population of people. Although the elevated expression of PKR (double stranded RNA-dependent protein kinase) and MMP-13 (collagenase-3) have been indicated to play pivotal roles in the pathogenesis of OA, the exact mechanism underlying the regulation of MMP-13 by PKR following inflammatory stimulation was relatively unknown. The purpose of this study was to determine the signaling pathway involved in the PKR-mediated induction of MMP-13 after TNF-α-stimulation. In this study, cartilages of knee joint were obtained from OA subjects who underwent arthroplastic knee surgery. Cartilages were used for tissue analysis or for chondrocytes isolation. In results, the upregulated expression of PKR was observed in damaged OA cartilages as well as in TNF-α-stimulated chondrocytes. Phosphorylation of PKC (protein kinase C) was found after TNF-α administration or PKR activation using poly(I:C), indicating PKC was regulated by PKR. The subsequent increased activity of NADPH oxidase led to oxidative stress accumulation and antioxidant capacity downregulation followed by an exaggerated inflammatory response with elevated levels of COX-2 and IL-8 via ERK/NF-κB pathway. Activated ERK pathway also impeded the inhibition of MMP-13 by PPAR-γ. These findings demonstrated that TNF-α-induced PKR activation triggered oxidative stress-mediated inflammation and MMP-13 in human chondrocytes. Unraveling these deregulated signaling cascades will deepen our knowledge of OA pathophysiology and provide aid in the development of novel therapies.
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Affiliation(s)
- Ching-Hou Ma
- Department of Orthopedics, E-Da Hospital/I-Shou University, Kaohsiung, Taiwan
| | - Chin-Hsien Wu
- Department of Orthopedics, E-Da Hospital/I-Shou University, Kaohsiung, Taiwan
| | - I-Ming Jou
- Department of Orthopedics, E-Da Hospital/I-Shou University, Kaohsiung, Taiwan
| | - Yuan-Kun Tu
- Department of Orthopedics, E-Da Hospital/I-Shou University, Kaohsiung, Taiwan
| | - Ching-Hsia Hung
- Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Ling Hsieh
- Institute of Oral Sciences, Chung Shan Medical University, Taichung, Taiwan.
| | - Kun-Ling Tsai
- Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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Abstract
A response to environmental stress is critical to alleviate cellular injury and maintain cellular homeostasis. Eukaryotic initiation factor 2 (eIF2) is a key integrator of cellular stress responses and an important regulator of mRNA translation. Diverse stress signals lead to the phosphorylation of the α subunit of eIF2 (Ser51), resulting in inhibition of global protein synthesis while promoting expression of proteins that mediate cell adaptation to stress. Here we report that eIF2α is instrumental in the control of noxious heat sensation. Mice with decreased eIF2α phosphorylation (eIF2α+/S51A) exhibit reduced responses to noxious heat. Pharmacological attenuation of eIF2α phosphorylation decreases thermal, but not mechanical, pain sensitivity, whereas increasing eIF2α phosphorylation has the opposite effect on thermal nociception. The impact of eIF2α phosphorylation (p-eIF2α) on thermal thresholds is dependent on the transient receptor potential vanilloid 1. Moreover, we show that induction of eIF2α phosphorylation in primary sensory neurons in a chronic inflammation pain model contributes to thermal hypersensitivity. Our results demonstrate that the cellular stress response pathway, mediated via p-eIF2α, represents a mechanism that could be used to alleviate pathological heat sensation.
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Song Y, Wan X, Gao L, Pan Y, Xie W, Wang H, Guo J. Activated PKR inhibits pancreatic β-cell proliferation through sumoylation-dependent stabilization of P53. Mol Immunol 2015; 68:341-9. [PMID: 26446704 DOI: 10.1016/j.molimm.2015.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/27/2015] [Accepted: 09/02/2015] [Indexed: 12/20/2022]
Abstract
Double-stranded RNA-dependent protein kinase (PKR) is intimately involved in type 2 diabetes due to its role in insulin resistance in peripheral tissues and anti-proliferative effect on pancreatic β-cells. Activated PKR was found to inhibit β-cell proliferation, partially through accumulation of P53. However the molecular mechanisms underlying PKR-dependent upregulation of P53 remain unknown. The results of the present study showed that PKR can be specifically activated in PKR overexpressing β-cells by a low dosage of the previously synthesized compound 1H-benzimidazole1-ethanol,2,3-dihydro-2-imino-a-(phenoxymethyl)-3-(phenylmethyl)-,monohydrochloride (BEPP), and this led to upregulation of P53 through sumoylation-dependent stability. Activated PKR was found to interact with sumo-conjugating enzyme Ubc9, and P53 sumoylation relies on a PKR-Ubc9 protein-protein interaction. Additionally, a ceramide signal was needed for PKR activation to be triggered by glucolipotoxicity and TNFα stimulation, and stabilization of P53 required endogenous ceramide accumulation. Glucolipotoxicity and pro-inflammatory cytokines therefore promote the sumoylation-dependent stability of P53 via the ceramide/PKR/Ubc9 signalling pathway that is involved in pancreatic β-cell proliferation inhibition in the development of type 2 diabetes.
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Affiliation(s)
- Ying Song
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China
| | - XiaoMeng Wan
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, PR China
| | - LiLi Gao
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, PR China
| | - Yi Pan
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, PR China
| | - WeiPing Xie
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China
| | - Hong Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China.
| | - Jun Guo
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, PR China
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Toro-Domínguez D, Carmona-Sáez P, Alarcón-Riquelme ME. Shared signatures between rheumatoid arthritis, systemic lupus erythematosus and Sjögren's syndrome uncovered through gene expression meta-analysis. Arthritis Res Ther 2014; 16:489. [PMID: 25466291 PMCID: PMC4295333 DOI: 10.1186/s13075-014-0489-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 11/10/2014] [Indexed: 01/01/2023] Open
Abstract
Introduction Systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and Sjögren’s syndrome (SjS) are inflammatory systemic autoimmune diseases (SADs) that share several clinical and pathological features. The shared biological mechanisms are not yet fully characterized. The objective of this study was to perform a meta-analysis using publicly available gene expression data about the three diseases to identify shared gene expression signatures and overlapping biological processes. Methods Previously reported gene expression datasets were selected and downloaded from the Gene Expression Omnibus database. Normalization and initial preprocessing were performed using the statistical programming language R and random effects model–based meta-analysis was carried out using INMEX software. Functional analysis of over- and underexpressed genes was done using the GeneCodis tool. Results The gene expression meta-analysis revealed a SAD signature composed of 371 differentially expressed genes in patients and healthy controls, 187 of which were underexpressed and 184 overexpressed. Many of these genes have previously been reported as significant biomarkers for individual diseases, but others provide new clues to the shared pathological state. Functional analysis showed that overexpressed genes were involved mainly in immune and inflammatory responses, mitotic cell cycles, cytokine-mediated signaling pathways, apoptotic processes, type I interferon–mediated signaling pathways and responses to viruses. Underexpressed genes were involved primarily in inhibition of protein synthesis. Conclusions We define a common gene expression signature for SLE, RA and SjS. The analysis of this signature revealed relevant biological processes that may play important roles in the shared development of these pathologies. Electronic supplementary material The online version of this article (doi:10.1186/s13075-014-0489-x) contains supplementary material, which is available to authorized users.
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Gilbert SJ, Meakin LB, Bonnet CS, Nowell MA, Ladiges WC, Morton J, Duance VC, Mason DJ. Deletion of P58(IPK), the Cellular Inhibitor of the Protein Kinases PKR and PERK, Causes Bone Changes and Joint Degeneration in Mice. Front Endocrinol (Lausanne) 2014; 5:174. [PMID: 25368604 PMCID: PMC4201149 DOI: 10.3389/fendo.2014.00174] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 10/01/2014] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE Protein kinase-like endoplasmic reticulum kinase (PERK) and protein kinase R (PKR) are implicated in endoplasmic reticulum stress-induced arthritis and pro-inflammatory cytokine-mediated cartilage degradation in vitro, respectively. We determined whether knockout of the cellular inhibitor of PERK and PKR, P58(IPK) causes joint degeneration in vivo and whether these molecules are activated in human osteoarthritis (OA). MATERIALS AND METHODS Sections of knee joints from P58(IPK)-null and wild-type mice aged 12-13 and 23-25 months were stained with toluidine blue and scored for degeneration using the osteoarthritis research society international (OARSI) system. Bone changes were assessed by radiology and high-resolution micro-computed tomography of hind limbs. Sections from the medial tibial plateaus of two human knees, removed in total knee replacement surgery for OA, were immunolabelled for phosphorylated PERK and PKR and P58(IPK). RESULTS Knockout mice exhibited narrower tibiae (p = 0.0031) and smaller epiphyses in tibiae (p = 0.0004) and femora (p = 0.0214). Older knockout mice had reduced total volume inside the femoral periosteal envelope (p = 0.023), reduced tibial (p = 0.03), and femoral (p = 0.0012) bone volumes (BV) and reduced femoral BV fraction (p = 0.025). Compared with wild-types, younger P58(IPK)-null mice had increased OARSI scores in medial femoral condyles (p = 0.035). Thirty four percent of null mice displayed severe joint degeneration with complete articular cartilage loss from the medial compartment and heterotopic chondro-osseous tissue in the medial joint capsule. Phosphorylated PERK and PKR were localized throughout human osteoarthritic tibial plateaus but, in particular, in areas exhibiting the most degeneration. There was limited expression of P58(IPK). CONCLUSION This study is the first to reveal a critical role for P58(IPK) in maintaining joint integrity in vivo, implicating the PKR and PERK stress signaling pathways in bony changes underlying the pathogenesis of joint degeneration.
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Affiliation(s)
- Sophie J. Gilbert
- Pathophysiology and Repair Division, Arthritis Research UK Biomechanics and Bioengineering Centre, School of Biosciences, Cardiff University, Cardiff, UK
| | - Lee B. Meakin
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - Cleo S. Bonnet
- Pathophysiology and Repair Division, Arthritis Research UK Biomechanics and Bioengineering Centre, School of Biosciences, Cardiff University, Cardiff, UK
| | - Mari A. Nowell
- Section of Inflammation, Skin and Joint Disease, Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, UK
| | - Warren C. Ladiges
- Department of Comparative Medicine, School of Medicine, University of Washington, Seattle, WA, USA
| | - John Morton
- Department of Comparative Medicine, School of Medicine, University of Washington, Seattle, WA, USA
| | - Victor C. Duance
- Pathophysiology and Repair Division, Arthritis Research UK Biomechanics and Bioengineering Centre, School of Biosciences, Cardiff University, Cardiff, UK
| | - Deborah J. Mason
- Pathophysiology and Repair Division, Arthritis Research UK Biomechanics and Bioengineering Centre, School of Biosciences, Cardiff University, Cardiff, UK
- *Correspondence: Deborah J. Mason, Arthritis Research UK Biomechanics and Bioengineering Centre, School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK e-mail:
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Derivatives of Dictyostelium discoideum differentiation-inducing factor-3 suppress the activities of Trypanosoma cruzi in vitro and in vivo. Biochem Pharmacol 2013; 85:1603-10. [PMID: 23511088 DOI: 10.1016/j.bcp.2013.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/05/2013] [Accepted: 03/06/2013] [Indexed: 11/21/2022]
Abstract
Chagas disease (human American trypanosomiasis), which is caused by the protozoan parasite Trypanosoma cruzi, is responsible for numerous deaths each year; however, established treatments for the disease are limited. Differentiation-inducing factor-1 (DIF-1) and DIF-3 are chlorinated alkylphenones originally found in the cellular slime mold Dictyostelium discoideum that have been shown to possess pharmacological activities. Here, we investigated the effects of DIF-3 derivatives on the infection rate and growth of T. cruzi by using an in vitro assay system utilizing host human fibrosarcoma HT1080 cells. Certain DIF-3 derivatives, such as butoxy-DIF-3 (Bu-DIF-3), at micro-molar levels strongly suppressed both the infection rate and growth of T. cruzi in HT1080 cells and exhibited little toxicity for HT1080 cells. For example, the IC50 of DIF-3 and Bu-DIF-3 versus the growth of T. cruzi in HT1080 cells were 3.95 and 0.72μM, respectively, and the LD50 of the two compounds versus HT1080 cells were both greater than 100μM. We also examined the effects of DIF-3 and Bu-DIF-3 on T. cruzi activity in C57BL/6 mice. Intraperitoneally administered Bu-DIF-3 (50mg/kg) significantly suppressed the number of trypomastigotes in blood with no apparent adverse effects. These results strongly suggest that DIF-3 derivatives could be new lead compounds in the development of anti-trypanosomiasis drugs.
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Double-stranded RNA-dependent protein kinase regulates insulin-stimulated chondrogenesis in mouse clonal chondrogenic cells, ATDC-5. Cell Tissue Res 2012. [PMID: 23180319 DOI: 10.1007/s00441-012-1521-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Double-stranded RNA-dependent protein kinase (PKR) is an interferon-induced protein that has been identified and characterized as a translational inhibitor in an interferon-regulated antiviral pathway. PKR is also reported to play important roles in the regulation of cell growth and differentiation. We have previously demonstrated that PKR inactivation suppresses osteoblast calcification and osteoclast formation. However, reports concerning the roles of PKR in chondrogenesis are limited. In this study, we have demonstrated that PKR is required for the in vitro differentiation of the mouse clonal chondrogenic cell line ATDC-5. ATDC-5 cells treated with insulin differentiated into chondrocytes and produced an alcian-blue-positive cartilage matrix. The protein expression of signal transducers and activators of transcription (STAT) peaked at day 7 of differentiation, whereas the expression of SRY-box-containing gene 9 (Sox-9), which is a transcription factor for chondrocyte differentiation, increased gradually. When the cells were treated with a PKR inhibitor (2-aminopurine), the cartilage matrix formation decreased. The protein expression of STAT1 continued to increase up to day 21, whereas the expression of Sox-9 was low and did not increase. We also demonstrated that PKR was localized to a marginal region of the mandibular condyle cartilage in mouse embryos. Our findings suggest that PKR has important functions in the differentiation of chondrocytes through the modulation of STAT1 and Sox-9 expression.
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Gilbert SJ, Singhrao SK, Khan IM, Gonzalez LG, Thomson BM, Burdon D, Duance VC, Archer CW. Enhanced tissue integration during cartilage repair in vitro can be achieved by inhibiting chondrocyte death at the wound edge. Tissue Eng Part A 2009; 15:1739-49. [PMID: 19119922 DOI: 10.1089/ten.tea.2008.0361] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE Experimental wounding of articular cartilage results in cell death at the lesion edge. The objective of this study was to investigate whether inhibition of this cell death results in enhanced integrative cartilage repair. METHODS Bovine articular cartilage discs (6 mm) were incubated in media containing inhibitors of necrosis (Necrostatin-1, Nec-1) or apoptosis (Z-VAD-FMK, ZVF) before cutting a 3 mm inner core. This core was left in situ to create disc/ring composites, cultured for up to 6 weeks with the inhibitors, and analyzed for cell death, sulfated glycosaminoglycan release, and tissue integration. RESULTS Creating the disc/ring composites resulted in a significant increase in necrosis. ZVF significantly reduced necrosis and apoptosis at the wound edge. Nec-1 reduced necrosis. Both inhibitors reduced the level of wound-induced sulfated glycosaminoglycan loss. Toluidine blue staining and electron microscopy of cartilage revealed significant integration of the wound edges in disc/ring composites treated with ZVF. Nec-1 improved integration, but to a lesser extent. Push-out testing revealed that ZVF increased adhesive strength compared to control composites. CONCLUSIONS This study shows that treatment of articular cartilage with cell death inhibitors during wound repair increases the number of viable cells at the wound edge, prevents matrix loss, and results in a significant improvement in cartilage-cartilage integration.
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Affiliation(s)
- Sophie J Gilbert
- Connective Tissue Biology Laboratories, School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom.
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Russell ST, Rajani S, Dhadda RS, Tisdale MJ. Mechanism of induction of muscle protein loss by hyperglycaemia. Exp Cell Res 2008; 315:16-25. [PMID: 18973755 DOI: 10.1016/j.yexcr.2008.10.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 10/02/2008] [Accepted: 10/03/2008] [Indexed: 02/03/2023]
Abstract
Treatment of murine myotubes with high glucose concentrations (10 and 25 mM) stimulated protein degradation through the ubiquitin-proteasome pathway, and also caused activation (autophosphorylation) of PKR (double-stranded-RNA-dependent protein kinase) and eIF2alpha (eukaryotic initiation factor 2alpha). Phosphorylation of PKR and eIF2alpha was also seen in the gastrocnemius muscle of diabetic ob/ob mice. High glucose levels also inhibited protein synthesis. The effect of glucose on protein synthesis and degradation was not seen in myotubes transfected with a catalytically inactive variant (PKRDelta6). High glucose also induced an increased activity of both caspase-3 and -8, which led to activation of PKR, since this was completely attenuated by the specific caspase inhibitors. Activation of PKR also led to activation of p38MAPK (mitogen activated protein kinase), leading to ROS (reactive oxygen species) formation, since this was attenuated by the specific p38MAPK inhibitor SB203580. ROS formation was important in protein degradation, since it was completely attenuated by the antioxidant butylated hydroxytoluene. These results suggest that high glucose induces muscle atrophy through the caspase-3/-8 induced activation of PKR, leading to phosphorylation of eIF2alpha and depression of protein synthesis, together with PKR-mediated ROS production, through p38MAPK and increased protein degradation.
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Affiliation(s)
- Steven T Russell
- Nutritional Biomedicine, School of Life and Health Sciences, Aston University, Birmingham B47ET, UK
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Gilbert SJ, Blain EJ, Duance VC, Mason DJ. Sphingomyelinase decreases type II collagen expression in bovine articular cartilage chondrocytes via the ERK signaling pathway. ACTA ACUST UNITED AC 2008; 58:209-20. [PMID: 18163502 DOI: 10.1002/art.23172] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Ceramide, a mediator of proinflammatory cytokine signaling, induces cartilage degradation and reduces type II collagen synthesis in articular cartilage. The accumulation of ceramide is associated with arthritis in Farber's disease. The aim of this study was to investigate the mechanism of ceramide-induced down-regulation of type II collagen. METHODS Bovine articular chondrocytes were stimulated with sphingomyelinase (SMase) to increase levels of endogenous ceramide. Components of the ERK pathway were inhibited by Raf-1 kinase inhibitor and the MEK inhibitor, PD98059. Cell extracts were analyzed by Western blotting for ERK-1/2, SOX9, c-Fos, and type II collagen, and the level of c-fos messenger RNA (mRNA) was analyzed by quantitative polymerase chain reaction. Localization of ERK-1/2, SOX9, and c-Fos was assessed by immunocytochemistry and confocal microscopy. RESULTS SMase treatment of chondrocytes caused sustained phosphorylation of ERK-1/2 throughout the cytoplasm and nucleus that was reduced by inhibitors of Raf-1 kinase and MEK-1/2. SMase treatment of chondrocytes also induced translocation of c-Fos to the nucleus and phospho-SOX9 to the cytoplasm and increased expression of c-fos mRNA. Type II collagen expression, which was down-regulated by SMase treatment, was restored by the MEK-1/2 inhibitor, PD98059. CONCLUSION SMase down-regulates type II collagen in articular chondrocytes via activation of the ERK signaling cascade, redistribution of SOX9, and recruitment of c-Fos. This new mechanism for cartilage degradation provides potential targets for future treatment of arthritic disease.
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von Holzen U, Pataer A, Raju U, Bocangel D, Vorburger SA, Liu Y, Lu X, Roth JA, Aggarwal BB, Barber GN, Keyomarsi K, Hunt KK, Swisher SG. The Double-Stranded RNA-Activated Protein Kinase Mediates Radiation Resistance in Mouse Embryo Fibroblasts through Nuclear Factor κB and Akt Activation. Clin Cancer Res 2007; 13:6032-9. [DOI: 10.1158/1078-0432.ccr-06-2932] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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Tam CL, Hofbauer M, Towle CA. Requirement for protein kinase R in interleukin-1alpha-stimulated effects in cartilage. Biochem Pharmacol 2007; 74:1636-41. [PMID: 17850766 PMCID: PMC2346584 DOI: 10.1016/j.bcp.2007.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 07/27/2007] [Accepted: 08/02/2007] [Indexed: 01/22/2023]
Abstract
Interleukin-1 (IL-1) has pleiotropic effects in cartilage. The interferon-induced, double stranded RNA-activated protein kinase PKR that phosphorylates eukaryotic initiation factor 2 (eIF2) alpha has been implicated in cytokine effects in chondrocytes. A compound was recently identified that potently suppresses PKR autophosphorylation (IC50 approximately 200 etaM) and partially restores PKR-inhibited translation in a cell-free system with significant effect in the nanomolar range. The objectives of this study were to exploit this potent PKR inhibitor to assess whether PKR kinase activity is required for catabolic and proinflammatory effects of IL-1alpha in cartilage and to determine whether IL-1alpha causes an increase in eIF2alpha phosphorylation that is antagonized by the PKR inhibitor. Cartilage explants were incubated with the PKR inhibitor and IL-1alpha. Culture media were assessed for sulfated glycosaminoglycan as an indicator of proteoglycan degradation and for prostaglandin E(2). Cartilage extracts were analyzed by Western blot for cyclooxygenase-2 and phosphorylated signaling molecules. Nanomolar concentrations of the PKR inhibitor suppressed proteoglycan degradation and cyclooxygenase-2 accumulation in IL-1alpha-activated cartilage. The PKR inhibitor stimulated or inhibited PGE(2) production with a biphasic dose response relationship. IL-1alpha increased the phosphorylation of both PKR and eIF2alpha, and nanomolar concentrations of PKR inhibitor suppressed the IL-1alpha-induced changes in phosphorylation. The results strongly support PKR involvement in pathways activated by IL-1alpha in chondrocytes.
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Affiliation(s)
- Christine L. Tam
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA
| | - Maria Hofbauer
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA
| | - Christine A. Towle
- Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA
- Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA
- Corresponding author: Address correspondence to Christine A. Towle, PhD, GRJ 1108, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114-2696 USA, phone: 1-(617) 724-3744; fax: 1-(617) 724-7396;
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Gilbert SJ, Blain EJ, Jones P, Duance VC, Mason DJ. Exogenous sphingomyelinase increases collagen and sulphated glycosaminoglycan production by primary articular chondrocytes: an in vitro study. Arthritis Res Ther 2007; 8:R89. [PMID: 16696862 PMCID: PMC1779424 DOI: 10.1186/ar1961] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 04/18/2006] [Accepted: 04/20/2006] [Indexed: 01/15/2023] Open
Abstract
We previously established a role for the second messenger ceramide in protein kinase R (PKR)-mediated articular cartilage degradation. Ceramide is known to play a dual role in collagen gene regulation, with the effect of ceramide on collagen promoter activity being dependent on its concentration. Treatment of cells with low doses of sphingomyelinase produces small increases in endogenous ceramide. We investigated whether ceramide influences articular chondrocyte matrix homeostasis and, if so, the role of PKR in this process. Bovine articular chondrocytes were stimulated for 7 days with sphingomyelinase to increase endogenous levels of ceramide. To inhibit PKR, 2-aminopurine was added to duplicate cultures. De novo sulphated glycosaminoglycan and collagen synthesis were measured by adding [35S]-sulphate and [3H]-proline to the media, respectively. Chondrocyte phenotype was investigated using RT-PCR and Western blot analysis. Over 7 days, sphingomyelinase increased the release of newly synthesized sulphated glycosaminoglycan and collagen into the media, whereas inhibition of PKR in sphingomyelinase-treated cells reduced the level of newly synthesized sulphated glycosaminoglycan and collagen. Sphingomyelinase treated chondrocytes expressed col2a1 mRNA, which is indicative of a normal chondrocyte phenotype; however, a significant reduction in type II collagen protein was detected. Therefore, small increments in endogenous ceramide in chondrocytes appear to push the homeostatic balance toward extracellular matrix synthesis but at the expense of the chondrocytic phenotype, which was, in part, mediated by PKR.
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Affiliation(s)
- Sophie J Gilbert
- Connective Tissue Biology Laboratories, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, Wales, UK
| | - Emma J Blain
- Connective Tissue Biology Laboratories, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, Wales, UK
| | - Pamela Jones
- Connective Tissue Biology Laboratories, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, Wales, UK
| | - Victor C Duance
- Connective Tissue Biology Laboratories, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, Wales, UK
| | - Deborah J Mason
- Connective Tissue Biology Laboratories, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, Wales, UK
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Bennett RL, Blalock WL, Abtahi DM, Pan Y, Moyer SA, May WS. RAX, the PKR activator, sensitizes cells to inflammatory cytokines, serum withdrawal, chemotherapy, and viral infection. Blood 2006; 108:821-9. [PMID: 16861340 PMCID: PMC1617065 DOI: 10.1182/blood-2005-11-006817] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
While the interferon (IFN)-inducible double-stranded RNA (dsRNA)-dependent protein kinase PKR is reported to initiate apoptosis in some instances, the mechanism by which diverse stress stimuli activate PKR remains unknown. Now we report that RAX, the only known cellular activator for PKR, initiates PKR activation in response to a broad range of stresses including serum deprivation, cytotoxic cytokine or chemotherapy treatment, or viral infection. Thus, knock-down of RAX expression by 80% using small interfering RNA (siRNA) prevents IFNgamma/tumor necrosis factor alpha (TNFalpha)-induced PKR activation and eIF2alpha phosphorylation, IkappaB degradation, IRF-1 expression, and STAT1 phosphorylation, resulting in enhanced murine embryonic fibroblast (MEF) cell survival. In contrast, expression of exogenous RAX, but not of the nonphosphorylatable, dominant-negative RAX(S18A) mutant, sensitizes cells to IFNgamma/TNFalpha, mitomycin C (MMC), or serum deprivation in association with increased PKR activity and apoptosis. Furthermore, RAX(S18A) expression in Fanconi anemia complementation group C-null MEF cells not only prevents PKR activation but also blocks hypersensitivity to IFNgamma/TNFalpha or mitomycin C that results in enhanced apoptosis. In addition, reduced RAX expression facilitates productive viral infection with vesicular stomatitis virus (VSV) and promotes anchorage-independent colony growth of MEF cells. Collectively, these data indicate that RAX may function as a negative regulator of growth that is required to activate PKR in response to a broad range of apoptosis-inducing stress.
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Affiliation(s)
- Richard L Bennett
- Department of Immunology and Molecular Genetics, Shands Cancer Center, University of Florida, Gainesville, USA
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Takada Y, Ichikawa H, Pataer A, Swisher S, Aggarwal BB. Genetic deletion of PKR abrogates TNF-induced activation of IkappaBalpha kinase, JNK, Akt and cell proliferation but potentiates p44/p42 MAPK and p38 MAPK activation. Oncogene 2006; 26:1201-12. [PMID: 16924232 DOI: 10.1038/sj.onc.1209906] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Double-stranded RNA-dependent protein kinase (PKR), a ubiquitously expressed serine/threonine kinase, has been implicated in the regulation or modulation of cell growth through multiple signaling pathways, but how PKR regulates tumor necrosis factor (TNF)-induced signaling pathways is poorly understood. In the present study, we used fibroblasts derived from PKR gene-deleted mice to investigate the role of PKR in TNF-induced activation of nuclear factor-kappaB (NF-kappaB), mitogen-activated protein kinases (MAPKs) and growth modulation. We found that in wild-type mouse embryonic fibroblast (MEF), TNF induced NF-kappaB activation as measured by DNA binding but deletion of PKR abolished this activation. This inhibition was associated with suppression of inhibitory subunit of NF-kappaB (IkappaB)alpha kinase (IKK) activation, IkappaBalpha phosphorylation and degradation, p65 phosphorylation and nuclear translocation, and NF-kappaB-dependent reporter gene transcription. TNF-induced Akt activation needed for IKK activation was also abolished by deletion of PKR. NF-kappaB activation was diminished in PKR-deleted cells transfected with TNF receptor (TNFR) 1, TNFR-associated death domain and TRAF2 plasmids; NF-kappaB activated by NF-kappaB-inducing kinase, IKK or p65, however, was minimally affected. Among the MAPKs, it was interesting that whereas TNF-induced c-Jun N-terminal kinase (JNK) activation was abolished, activation of p44/p42 MAPK and p38 MAPK was potentiated in PKR-deleted cells. TNF induced the expression of NF-kappaB-regulated gene products cyclin D1, c-Myc, matrix metalloproteinase-9, survivin, X-linked inhibitor-of-apoptosis protein (IAP), IAP1, Bcl-x(L), A1/Bfl-1 and Fas-associated death domain protein-like IL-1beta-converting enzyme-inhibitory protein in wild-type MEF but not in PKR-/- cells. Similarly, TNF induced the proliferation of wild-type cells, but this proliferation was completely suppressed in PKR-deleted cells. Overall, our results indicate that PKR differentially regulates TNF signaling; IKK, Akt and JNK were positively regulated, whereas p44/p42 MAPK and p38 MAPK were negatively regulated.
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Affiliation(s)
- Y Takada
- Cytokine Research Laboratory, Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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Pachman LM, Boskey AL. Clinical manifestations and pathogenesis of hydroxyapatite crystal deposition in juvenile dermatomyositis. Curr Rheumatol Rep 2006; 8:236-43. [PMID: 16901083 DOI: 10.1007/s11926-996-0031-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pathologic deposition of mineral in the form of bone-like hydroxyapatite is a frequent occurrence in juvenile dermatomyositis (JDM) and other connective tissue diseases. Although the sizes of the mineral crystals in JDM are similar to those in bone, there is much more mineral in the deposits than there is in bone. Bone matrix proteins also accumulate associated with the deposits. The reasons for the formation of these deposits are not known. It is our hypothesis that persistent inflammation is a component of JDM and other hydroxyapatite deposition diseases. Other contributing factors are genetic, environmental, and physical chemical. This paper discusses the influence of inflammation on the deposition of hydroxyapatite, with emphasis on the clinical and environmental factors that may facilitate the formation of calcific deposits in JDM.
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Affiliation(s)
- Lauren M Pachman
- Molecular and Cellular Pathobiology Program, The Children's Memorial Research Center, Chicago, IL 60614, USA.
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Hatabu T, Takada T, Taguchi N, Suzuki M, Sato K, Kano S. Potent plasmodicidal activity of a heat-induced reformulation of deoxycholate-amphotericin B (Fungizone) against Plasmodium falciparum. Antimicrob Agents Chemother 2005; 49:493-6. [PMID: 15673723 PMCID: PMC547284 DOI: 10.1128/aac.49.2.493-496.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emergence and spread of drug-resistant Plasmodium falciparum continue to pose problems in malaria chemotherapy. Therefore, it is necessary to identify new antimalarial drugs and therapeutic strategies. In the present study, the activity of a heat-treated form of amphotericin B (HT-AMB) against P. falciparum was evaluated. The efficacy and toxicity of HT-AMB were also compared with those of the standard formulation (AMB). HT-AMB showed significant activity against a chloroquine-resistant strain (strain K-1) and a chloroquine-susceptible strain (strain FCR-3) in vitro. The 50% inhibitory concentrations of HT-AMB were 0.32 +/- 0.03 mug/ml for strain K-1 and 0.33 +/- 0.03 mug/ml for strain FCR-3. In the presence of 1.0 mug of HT-AMB per ml, only pyknotic parasites were observed after 24 h of incubation of early trophozoites (ring forms). However, when late trophozoites and schizonts were cultured with 1.0 mug of HT-AMB per ml, those forms multiplied to ring forms but the number of infected erythrocytes did not increase. These results indicate that HT-AMB possesses potent antiplasmodial activity and that the drug is more effective against the ring-form stage than against the late trophozoite and schizont stages. HT-AMB was observed to have little cytotoxic effect against a human liver cell line (Chang liver cells). In conclusion, the results suggest that HT-AMB has promising properties and merits further in vivo investigations as a treatment for falciparum malaria.
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Affiliation(s)
- Toshimitsu Hatabu
- Gunma University School of Health Sciences, 3-39-15 Showa-machi, Maebashi 371-8514, Japan.
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Wang YT, Huang ZJ, Chang HM. Proteomic Analysis of Human Leukemic U937 Cells Incubated with Conditioned Medium of Mononuclear Cells Stimulated by Proteins from Dietary Mushroom of Agrocybe aegerita. J Proteome Res 2004; 3:890-6. [PMID: 15359746 DOI: 10.1021/pr049922h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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