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Nam SW, Hwang JW, Han YH. A novel berberine derivative targeting adipocyte differentiation to alleviate TNF-α-induced inflammatory effects and insulin resistance in OP9 cells. Biomed Pharmacother 2023; 167:115433. [PMID: 37696086 DOI: 10.1016/j.biopha.2023.115433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/22/2023] [Accepted: 08/31/2023] [Indexed: 09/13/2023] Open
Abstract
Inflammation and insulin resistance play important roles in the development and progression of type 2 diabetes mellitus. The enhancement of adipocyte differentiation can improve insulin sensitivity by increasing glucose uptake, improving insulin signaling, and reducing inflammation. However, only a few adipogenic agents have shown clinical success in patients with type 2 diabetes mellitus. The therapeutic potential of berberine in type 2 diabetes mellitus was confirmed in terms of the target gene-disease relationship using a network pharmacology database prior to synthesizing the derivatives. Novel berberine derivatives were synthesized, and compound 3b promoted adipocyte differentiation and improvement of insulin resistance in OP9 cells. Compound 3b significantly increased the expression of key adipogenic markers including peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein β (C/EBPβ) and promoted lipid accumulation without cytotoxicity. Furthermore, tumor necrosis factor α (TNF-α)-induced inhibition of adipocyte differentiation and the elevation of inflammatory responses were reversed by compound 3b. Subsequently glucose uptake level through insulin sensitivity improvement was enhanced by compound 3b. Mechanistically, TNF-α activated mitogen-activated protein kinases (MAPKs): ERK, JNK, and p38, whereas compound 3b attenuated phosphorylation of three MAPKs. Finally, in silico molecular docking suggested the possible binding sites of compound 3b on PPARγ. Collectively, the adipogenic and glucose uptake effects of compound 3b were associated with its anti-inflammatory effects and reduced phosphorylation of MAPKs. These findings suggest that the berberine derivative compound 3b may be a potent antidiabetic agent.
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Affiliation(s)
- Seo Woo Nam
- Department of Biomedical Science, College of Medicine, Wonkwang University, Iksan, the Republic of Korea
| | - Jin Wook Hwang
- INSERM UA09, University Paris Saclay, 94800 Villejuif, France
| | - Youn Ho Han
- Department of Oral Pharmacology, College of Dentistry, Wonkwang University, Iksan, the Republic of Korea.
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Attiq A, Afzal S. Trinity of inflammation, innate immune cells and cross-talk of signalling pathways in tumour microenvironment. Front Pharmacol 2023; 14:1255727. [PMID: 37680708 PMCID: PMC10482416 DOI: 10.3389/fphar.2023.1255727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 08/08/2023] [Indexed: 09/09/2023] Open
Abstract
Unresolved inflammation is a pathological consequence of persistent inflammatory stimulus and perturbation in regulatory mechanisms. It increases the risk of tumour development and orchestrates all stages of tumorigenesis in selected organs. In certain cancers, inflammatory processes create the appropriate conditions for neoplastic transformation. While in other types, oncogenic changes pave the way for an inflammatory microenvironment that leads to tumour development. Of interest, hallmarks of tumour-promoting and cancer-associated inflammation are striking similar, sharing a complex network of stromal (fibroblasts and vascular cells) and inflammatory immune cells that collectively form the tumour microenvironment (TME). The cross-talks of signalling pathways initially developed to support homeostasis, change their role, and promote atypical proliferation, survival, angiogenesis, and subversion of adaptive immunity in TME. These transcriptional and regulatory pathways invariably contribute to cancer-promoting inflammation in chronic inflammatory disorders and foster "smouldering" inflammation in the microenvironment of various tumour types. Besides identifying common target sites of numerous cancer types, signalling programs and their cross-talks governing immune cells' plasticity and functional diversity can be used to develop new fate-mapping and lineage-tracing mechanisms. Here, we review the vital molecular mechanisms and pathways that establish the connection between inflammation and tumour development, progression, and metastasis. We also discussed the cross-talks between signalling pathways and devised strategies focusing on these interaction mechanisms to harness synthetic lethal drug combinations for targeted cancer therapy.
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Affiliation(s)
- Ali Attiq
- Discipline of Pharmacology, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang, Malaysia
| | - Sheryar Afzal
- Department of Biomedical Sciences, Faculty of Veterinary Medicine, King Faisal University, Al Ahsa, Saudi Arabia
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3
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Yang H, Chen T, Denoyelle S, Chen L, Fan J, Zhang Y, Halperin JA, Chorev M, Aktas BH. Role of symmetry in 3,3-diphenyl-1,3-dihydroindol-2-one derivatives as inhibitors of translation initiation. Bioorg Med Chem Lett 2023; 80:129119. [PMID: 36581302 PMCID: PMC9922553 DOI: 10.1016/j.bmcl.2022.129119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/13/2022] [Accepted: 12/23/2022] [Indexed: 12/28/2022]
Abstract
The ternary complex (eIF2·GTP·Met-tRNAiMet) and the eIF4F complex assembly are two major regulatory steps in the eukaryotic translation initiation. Inhibition of the ternary complex assembly is therefore a promising target for the development of novel anti-cancer therapeutics. Building on the finding that clotrimazole (CLT), a molecular probe that depletes intracellular Ca2+ stores and subsequently induce eIF2α phosphorylation, inhibit translation initiation, and reduce preferentially the expression of oncoproteins over "housekeeping" ones,1-3 we undertook structure activity relationship (SAR) studies that identified 3,3-diarylindoline-2-one #1181 as an interesting scaffold. Compound #1181 also induce phosphorylation of eIF2α thereby reducing the availability of the ternary complex, which leads to inhibition of translation initiation.4 Our subsequent efforts focused on understanding SAR iterative lead optimization to enhance potency and improve bioavailability. Herein, we report a complementing study focusing on heavily substituted symmetric and asymmetric 3,3-(o,m-disubstituted)diarylindoline-2-ones. These compounds were evaluated by the dual luciferase reporter ternary complex assay that recapitualates phosphorylation of eIF2α in a quantitative manner. We also evaluated all compounds by sulforhodamine B assay, which measures the overall effect of compounds on cell proliferations and/or viability.
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Affiliation(s)
- Hongwei Yang
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA.
| | - Ting Chen
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Séverine Denoyelle
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Limo Chen
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Jing Fan
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Yingzhen Zhang
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - José A Halperin
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA; Harvard Medical School, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Michael Chorev
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA; Harvard Medical School, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA.
| | - Bertal H Aktas
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA; Harvard Medical School, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA.
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4
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Ginsenoside Rb1 from Panax notoginseng Suppressed TNF-α-Induced Matrix Metalloproteinase-9 via the Suppression of Double-Strand RNA-Dependent Protein Kinase (PKR)/NF-κB Pathway. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27228050. [PMID: 36432152 PMCID: PMC9692425 DOI: 10.3390/molecules27228050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/12/2022] [Accepted: 11/16/2022] [Indexed: 11/22/2022]
Abstract
Chronic inflammation is commonly accompanied by the stimulation of matrix metalloproteinases (MMPs) production and the degradation of the extracellular matrix. The overexpression of MMP-9 (Gelatinase B) highly participates in the progression of pathetic cardiac remodeling and liver cancer metastasis. Panax notoginseng (Burkill) F. H. Chen (Sanqi), a widely used traditional Chinese medicinal herb, shows myocardial protective and anti-tumor effects. In this study, we examined the inhibitory effect of different PNG extracts on tumor necrosis factor (TNF)-α-induced MMP-9 expression in cardiac myoblast H9c2 cells. Using a bioassay-guided fractionation scheme, the most active extract was fractionated by silica gel column chromatography and high-performance liquid chromatography until an active compound was obtained. The compound was identified as Ginsenoside Rb1 by nuclear magnetic resonance. Ginsenoside Rb1 inhibited TNF-α-induced MMP-9 production in both H9c2 and liver carcinoma HepG-2 cells. Interestingly, it did not affect the MMP-2 (Gelatinase A) level and the cell proliferation of the two cell lines. The inhibitory effects of Ginsenoside Rb1 may be due to its modulation of double-strand RNA-dependent protein kinase and nuclear factor kappa B signaling pathways. The results reveal the potential use of Ginsenoside Rb1 for the treatment of inflammatory and MMP-9-related cardiac remodeling and metastasis of hepatocellular carcinomas.
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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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6
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Zhang J, Zhang X, Li L, Bai L, Gao Y, Yang Y, Wang L, Qiao Y, Wang X, Xu JT. Activation of Double-Stranded RNA-Activated Protein Kinase in the Dorsal Root Ganglia and Spinal Dorsal Horn Regulates Neuropathic Pain Following Peripheral Nerve Injury in Rats. Neurotherapeutics 2022; 19:1381-1400. [PMID: 35655111 PMCID: PMC9587175 DOI: 10.1007/s13311-022-01255-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2022] [Indexed: 10/18/2022] Open
Abstract
Double-stranded RNA (dsRNA)-activated kinase (PKR) is an important component in inflammation and immune dysfunction. However, the role of PKR in neuropathic pain remains unclear. Here, we showed that lumbar 5 spinal nerve ligation (SNL) led to a significant increase in the level of phosphorylated PKR (p-PKR) in both the dorsal root ganglia (DRG) and spinal dorsal horn. Images of double immunofluorescence staining revealed that p-PKR was expressed in myelinated A-fibers, unmyelinated C-fibers, and satellite glial cells in the DRG. In the dorsal horn, p-PKR was located in neuronal cells, astrocytes, and microglia. Data from behavioral tests showed that intrathecal (i.t.) injection of 2-aminopurine (2-AP), a specific inhibitor of PKR activation, and PKR siRNA prevented the reductions in PWT and PWL following SNL. Established neuropathic pain was also attenuated by i.t. injection of 2-AP and PKR siRNA, which started on day 7 after SNL. Prior repeated i.t. injections of PKR siRNA prevented the SNL-induced degradation of IκBα and IκBβ in the cytosol and the nuclear translocation of nuclear factor κB (NF-κB) p65 in both the DRG and dorsal horn. Moreover, the SNL-induced increase in interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) production was diminished by this treatment. Collectively, these results suggest that peripheral nerve injury-induced PKR activation via NF-κB signaling-regulated expression of proinflammatory cytokines in the DRG and dorsal horn contributes to the pathogenesis of neuropathic pain. Our findings suggest that pharmacologically targeting PKR might be an effective therapeutic strategy for the treatment of neuropathic pain.
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Affiliation(s)
- Jian Zhang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Xuan Zhang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Liren Li
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Liying Bai
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital, Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450052, China
| | - Yan Gao
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Yin Yang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Li Wang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Yiming Qiao
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Xueli Wang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Ji-Tian Xu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China.
- Neuroscience Research Institute, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China.
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Song H, Tian D, Sun J, Mao X, Kong W, Xu D, Ji Y, Qiu B, Zhan M, Wang J. circFAM120B functions as a tumor suppressor in esophageal squamous cell carcinoma via the miR-661/PPM1L axis and the PKR/p38 MAPK/EMT pathway. Cell Death Dis 2022; 13:361. [PMID: 35436983 PMCID: PMC9016076 DOI: 10.1038/s41419-022-04818-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 03/18/2022] [Accepted: 03/31/2022] [Indexed: 02/07/2023]
Abstract
Extensive changes of circRNA expression underscore their essential contributions to multiple hallmarks of cancers; however, their functions and mechanisms of action in esophageal squamous cell carcinoma (ESCC) remain undetermined. Here, we adopted a three-stage approach by first screening for significantly differentially expressed circRNAs in ESCC and performing an external validation study, followed by the functional analyses. The properties of circRNAs were evaluated using Sanger sequencing, RNase R digestion, actinomycin D treatment, subcellular localization analysis, and fluorescence in situ hybridization. Target transcripts were predicted using online tools and verified by dual-luciferase, RNA immunoprecipitation, qRT-PCR, and western blot. Biotin-labeled RNA-protein pull-down, mass spectrometry, and RNA immunoprecipitation were employed to identify proteins interacting with circRNAs. Gain- and loss-of-function experiments were performed to uncover the roles of circRNAs, their target genes, and binding proteins in the proliferation, metastasis, and invasion. We observed that circFAM120B (hsa_circ_0001666) was frequently downregulated in cancer tissues and patient plasma, and its expression level was related to overall survival in ESCC patients. Overexpression of circFAM120B inhibited the proliferation, metastasis, and invasion of ESCC while silencing it enhanced malignant phenotypes. Mechanistically, circFAM120B was predominantly located in the cytoplasm, guarantying its sponging for miR-661 to restore the expression of PPM1L, a tumor suppressor. We observed that circFAM120B could reduce the stability of RNA-dependent protein kinase (PKR) by promoting its ubiquitination-dependent degradation and subsequently regulating the p38 MAPK signaling pathway, resulting in the repression of EMTs in ESCC cells. Our findings suggest that circFAM120B is a promising biomarker of ESCC, which acts as a tumor suppressor via the circFAM120B/miR-661/PPM1L axis and PKR/p38 MAPK/EMT pathway, supporting its significance as a candidate therapeutic target.
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Affiliation(s)
- Huan Song
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Dan Tian
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Jian Sun
- Department of Thoracic Surgery, The First People's Hospital of Yancheng and Yancheng Clinical College of Xuzhou Medical University, Yancheng, 224001, China
| | - Xuhua Mao
- Department of Clinical Laboratory, Yixing People's Hospital, Wuxi, 214200, China
| | - Weimin Kong
- Department of Thoracic Surgery, The First People's Hospital of Yancheng and Yancheng Clinical College of Xuzhou Medical University, Yancheng, 224001, China
| | - Dian Xu
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Ye Ji
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Beibei Qiu
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Mengyao Zhan
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Jianming Wang
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China. .,Department of Epidemiology, Gusu School, Nanjing Medical University, Nanjing, 211166, China.
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Kamble SS, Choudhari J, Nimma R, Kumar TVS, Patil KK, Hese SV, Dawane BS, Gacche RN. Chloroxylon swietenia (Roxb.) DC induces cell death and apoptosis by down-regulating the NF-κB pathway in MCF-7 breast cancer cells: In vitro and in vivo investigations. Cancer Rep (Hoboken) 2022; 5:e1600. [PMID: 35274824 PMCID: PMC9575507 DOI: 10.1002/cnr2.1600] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 10/25/2021] [Accepted: 12/29/2021] [Indexed: 11/14/2022] Open
Abstract
Background Natural products with targeted bioactivity have gained major attention in the field of cancer research owing to emerging anti‐cancer drug resistance and off target toxicities. Chloroxylon swietenia (Roxb.) DC is recognized as a folklore medicinal plant and has numerous therapeutic benefits in the folklore medicine system, however the anti‐cancer potential of this plant and its mechanism of action is poorly understood. Aims The aim of the study was to investigate the anti‐breast cancer efficacy of C. swietenia leaves methanol extract (CSLME) against MCF‐7 hormone dependent human breast cancer cell line with possible mechanism of action. Methods and results The anti‐breast cancer activity of CSLME against MCF‐7 cells was assessed by evaluating its efficacy toward cytotoxicity, cell migration, colony formation, DNA fragmentation, apoptosis, cytoskeleton, angiogenesis, cell cycle regulation, and animal toxicity. The preliminary screening of CSLME against MCF‐7 cells revealed the cytotoxicity (IC50 20 μg/ml), inhibited cell migration, colony formation, and angiogenesis. It was observed that CSLME induces apoptosis by nuclear fragmentation and disruption of cytoskeleton by actin derangement. The results of Annexin V‐FITC assay and cell cycle analysis by flow cytometry clearly pointed out the sizable fraction of apoptotic cells, and arrested the cells at G2/M phase of cell cycle. The results of the immunoblotting experiments showed that CSLME activates intrinsic pathway of apoptosis with down regulation of anti‐apoptotic marker like Bcl2, up regulation of pro‐apoptotic markers like Bax & Bad, along with successful cleavage of Caspase‐9 and PARP‐1. Further, western blot analysis revealed the possible down regulation of NF‐κB pathway by CSLME, which may be responsible for anti‐cancer activity in MCF‐7 cells. In vivo animal model studies using NOD‐SCID mice demonstrated impressive anti‐tumor activity with significant reduction in tumor volume of MCF‐7 tumor xenograft. Of note, in‐vivo acute oral toxicity study as per Organization for Economic Cooperation and Development 423 revealed the nontoxic nature of CSLME. Conclusion The in vitro and in vivo findings clearly outline the potential of CSLME as inhibitor of growth and proliferation of MCF‐7 cells. Mechanistically, CSLME seems to activate intrinsic pathway of apoptosis, arrest cell cycle, target actin cytoskeleton, inhibit growth, colony formation, migration, and angiogenesis, with down regulation of NF‐κB pathway leading to cell death.
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Affiliation(s)
- Sonali S Kamble
- Department of Biochemistry, Gramin Science (Vocational) College, Nanded, India
| | - Jasoda Choudhari
- Department of Biotechnology, Savitribai Phule Pune University, Pune, India
| | | | | | - Kapil K Patil
- Government Medical College & Hospital, Aurangabad, India
| | | | - Bhaskar S Dawane
- School of Chemical Sciences, Swami Ramanand Teerth Marathwada University, Nanded, India
| | - Rajesh N Gacche
- Department of Biotechnology, Savitribai Phule Pune University, Pune, India
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9
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The IRENA lncRNA converts chemotherapy-polarized tumor-suppressing macrophages to tumor-promoting phenotypes in breast cancer. NATURE CANCER 2022; 2:457-473. [PMID: 35122000 DOI: 10.1038/s43018-021-00196-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 03/12/2021] [Indexed: 11/09/2022]
Abstract
Although chemotherapy can stimulate antitumor immunity by inducing interferon (IFN) response, the functional role of tumor-associated macrophages in this scenario remains unclear. Here, we found that IFN-activated proinflammatory macrophages after neoadjuvant chemotherapy enhanced antitumor immunity but promoted cancer chemoresistance. Mechanistically, IFN induced expression of cytoplasmic long noncoding RNA IFN-responsive nuclear factor-κB activator (IRENA) in macrophages, which triggered nuclear factor-κB signaling via dimerizing protein kinase R and subsequently increased production of protumor inflammatory cytokines. By constructing macrophage-conditional IRENA-knockout mice, we found that targeting IRENA in IFN-activated macrophages abrogated their protumor effects, while retaining their capacity to enhance antitumor immunity. Clinically, IRENA expression in post-chemotherapy macrophages was associated with poor patient survival. These findings indicate that lncRNA can determine the dichotomy of inflammatory cells on cancer progression and antitumor immunity and suggest that targeting IRENA is an effective therapeutic strategy to reversing tumor-promoting inflammation.
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Mangali S, Bhat A, Dasari D, Sriram D, Dhar A. Inhibition of double stranded RNA dependent protein kinase (PKR) abrogates isoproterenol induced myocardial ischemia in vitro in cultured cardiomyocytes and in vivo in wistar rats. Eur J Pharmacol 2021; 906:174223. [PMID: 34081906 DOI: 10.1016/j.ejphar.2021.174223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 05/22/2021] [Accepted: 05/28/2021] [Indexed: 12/29/2022]
Abstract
Protein kinase R (PKR) plays a main role in inflammation, insulin resistance, and glucose balance. It is activated by various stress signals and is key mediators of diabetes and associated complications. In the present study, we investigated the effect of PKR inhibition on myocardial dysfunction, inflammatory, cell death and interrelated signalling pathways in isoproterenol induced myocardial ischemia in vivo in wistar rats and in vitro in cultured cardiomyocytes. H9C2 rat cardiomyocytes were treated with 10 μM Isoproterenol (ISO). For in vivo studies, rats were divided into 4 groups: control, ischemic group (ISO), preventive group, curative group and each group consist of 8 rats. Myocardial Ischemia (MI) was induced with two subsequent doses of ISO (100 mg/kg, s.c.). The rats were treated with PKR inhibitor, C16 (166.5 μg/kg, i.p.) for 14 days. Heart rate, systolic, diastolic and mean arterial pressures were measured by non-invasive BP apparatus. Cardiac biomarkers were measured by commercial kits. Ischemic Zone, Morphological abnormalities and fibrosis of heart was detected by TTC, haematoxylin & eosin staining, Masson's and Sirius red staining respectively. Protein expression was done by western blotting and immune histochemistry. mRNA expression was done by RT-PCR. MI was characterized by declined myocardial performance along with elevation of cardiac biomarkers and associated with increased expression of PKR, oxidative-nitrosative stress, activated various inflammatory pathways (nuclear factor kappa light chain enhancer of activated B cells -NF-κB); Mitogen-activated protein kinases-MAPK; c-Jun N-terminal kinase-JNK), increased expression of inflammatory markers (Tumour necrosis factor alpha-TNF-α), markers of fibrosis (Alpha smooth muscle actin -α-SMA; Transforming growth factor beta-TGF-β), enhanced cell death (Ischemic zone) and increased expression of extracellular regulated-kinases (ERK-1/2) and advanced glycation end products (AGE's). Interestingly, inhibition of PKR attenuated myocardial dysfunction, cardiac fibrosis, oxidative/nitrosative stress, inflammation, cell death, and inter-related signalling pathways. Our findings report that inhibition of PKR improves the ischemic mediated inflammation, apoptosis, cardiac hypertrophy and fibrosis in MI induced rats. Hence, inhibition of PKR might be one of intervention therapy for the treatment of myocardial ischemia.
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Affiliation(s)
- Sureshbabu Mangali
- Department of Pharmacy, Birla Institute of Technology and Sciences (BITS) Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet, Hyderabad, Telangana, 500078, India
| | - Audesh Bhat
- Department of Molecular Biology, Central University of Jammu, India
| | - Deepika Dasari
- Department of Pharmacy, Birla Institute of Technology and Sciences (BITS) Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet, Hyderabad, Telangana, 500078, India
| | - Dharmarajan Sriram
- Department of Pharmacy, Birla Institute of Technology and Sciences (BITS) Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet, Hyderabad, Telangana, 500078, India
| | - Arti Dhar
- Department of Pharmacy, Birla Institute of Technology and Sciences (BITS) Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet, Hyderabad, Telangana, 500078, India.
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11
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Declerck K, Novo CP, Grielens L, Van Camp G, Suter A, Vanden Berghe W. Echinacea purpurea (L.) Moench treatment of monocytes promotes tonic interferon signaling, increased innate immunity gene expression and DNA repeat hypermethylated silencing of endogenous retroviral sequences. BMC Complement Med Ther 2021; 21:141. [PMID: 33980308 PMCID: PMC8114977 DOI: 10.1186/s12906-021-03310-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 04/27/2021] [Indexed: 12/12/2022] Open
Abstract
Background Herbal remedies of Echinacea purpurea tinctures are widely used today to reduce common cold respiratory tract infections. Methods Transcriptome, epigenome and kinome profiling allowed a systems biology level characterisation of genomewide immunomodulatory effects of a standardized Echinacea purpurea (L.) Moench extract in THP1 monocytes. Results Gene expression and DNA methylation analysis revealed that Echinaforce® treatment triggers antiviral innate immunity pathways, involving tonic IFN signaling, activation of pattern recognition receptors, chemotaxis and immunometabolism. Furthermore, phosphopeptide based kinome activity profiling and pharmacological inhibitor experiments with filgotinib confirm a key role for Janus Kinase (JAK)-1 dependent gene expression changes in innate immune signaling. Finally, Echinaforce® treatment induces DNA hypermethylation at intergenic CpG, long/short interspersed nuclear DNA repeat elements (LINE, SINE) or long termininal DNA repeats (LTR). This changes transcription of flanking endogenous retroviral sequences (HERVs), involved in an evolutionary conserved (epi) genomic protective response against viral infections. Conclusions Altogether, our results suggest that Echinaforce® phytochemicals strengthen antiviral innate immunity through tonic IFN regulation of pattern recognition and chemokine gene expression and DNA repeat hypermethylated silencing of HERVs in monocytes. These results suggest that immunomodulation by Echinaforce® treatment holds promise to reduce symptoms and duration of infection episodes of common cold corona viruses (CoV), Severe Acute Respiratory Syndrome (SARS)-CoV, and new occurring strains such as SARS-CoV-2, with strongly impaired interferon (IFN) response and weak innate antiviral defense. Supplementary Information The online version contains supplementary material available at 10.1186/s12906-021-03310-5.
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Affiliation(s)
- Ken Declerck
- Laboratory of Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp (UA), Antwerp, Belgium
| | - Claudina Perez Novo
- Laboratory of Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp (UA), Antwerp, Belgium
| | - Lisa Grielens
- Laboratory of Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp (UA), Antwerp, Belgium
| | - Guy Van Camp
- Center of Medical Genetics, Department of Biomedical Sciences, University of Antwerp (UA) and University Hospital Antwerp (UZA), Antwerp, Belgium
| | | | - Wim Vanden Berghe
- Laboratory of Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp (UA), Antwerp, Belgium.
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12
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Eiermann N, Haneke K, Sun Z, Stoecklin G, Ruggieri A. Dance with the Devil: Stress Granules and Signaling in Antiviral Responses. Viruses 2020; 12:v12090984. [PMID: 32899736 PMCID: PMC7552005 DOI: 10.3390/v12090984] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023] Open
Abstract
Cells have evolved highly specialized sentinels that detect viral infection and elicit an antiviral response. Among these, the stress-sensing protein kinase R, which is activated by double-stranded RNA, mediates suppression of the host translation machinery as a strategy to limit viral replication. Non-translating mRNAs rapidly condensate by phase separation into cytosolic stress granules, together with numerous RNA-binding proteins and components of signal transduction pathways. Growing evidence suggests that the integrated stress response, and stress granules in particular, contribute to antiviral defense. This review summarizes the current understanding of how stress and innate immune signaling act in concert to mount an effective response against virus infection, with a particular focus on the potential role of stress granules in the coordination of antiviral signaling cascades.
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Affiliation(s)
- Nina Eiermann
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Katharina Haneke
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Zhaozhi Sun
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
| | - Georg Stoecklin
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Alessia Ruggieri
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
- Correspondence:
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13
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Piazzi M, Bavelloni A, Faenza I, Blalock W. Glycogen synthase kinase (GSK)-3 and the double-strand RNA-dependent kinase, PKR: When two kinases for the common good turn bad. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118769. [PMID: 32512016 PMCID: PMC7273171 DOI: 10.1016/j.bbamcr.2020.118769] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 01/08/2023]
Abstract
Glycogen synthase kinase (GSK)-3α/β and the double-stranded RNA-dependent kinase PKR are two sentinel kinases that carry-out multiple similar yet distinct functions in both the cytosol and the nucleus. While these kinases belong to separate signal transduction cascades, they demonstrate an uncanny propensity to regulate many of the same proteins either through direct phosphorylation or by altering transcription/translation, including: c-MYC, NF-κB, p53 and TAU, as well as each another. A significant number of studies centered on the GSK3 kinases have led to the identification of the GSK3 interactome and a number of substrates, which link GSK3 activity to metabolic control, translation, RNA splicing, ribosome biogenesis, cellular division, DNA repair and stress/inflammatory signaling. Interestingly, many of these same pathways and processes are controlled by PKR, but unlike the GSK3 kinases, a clear picture of proteins interacting with PKR and a complete listing of its substrates is still missing. In this review, we take a detailed look at what is known about the PKR and GSK3 kinases, how these kinases interact to influence common cellular processes (innate immunity, alternative splicing, translation, glucose metabolism) and how aberrant activation of these kinases leads to diseases such as Alzheimer's disease (AD), diabetes mellitus (DM) and cancer. GSK3α/β and PKR are major regulators of cellular homeostasis and the response to stress/inflammation and infection. GSK3α/β and PKR interact with and/or modify many of the same proteins and affect the expression of similar genes. A balance between AKT and PKR nuclear signaling may be responsible for regulating the activation of nuclear GSK3β. GSK3α/β- and PKR-dependent signaling influence major molecular mechanisms of the cell through similar intermediates. Aberrant activation of GSK3α/β and PKR is highly involved in cancer, metabolic disorders, and neurodegenerative diseases.
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Affiliation(s)
- Manuela Piazzi
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", Consiglio Nazionale delle Ricerche (IGM-CNR), Bologna, Italy; IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Alberto Bavelloni
- Laboratoria di Oncologia Sperimentale, IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Irene Faenza
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - William Blalock
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", Consiglio Nazionale delle Ricerche (IGM-CNR), Bologna, Italy; IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy.
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14
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Xu M, Xie F, Tang X, Wang T, Wang S. Insights into the role of circular RNA in macrophage activation and fibrosis disease. Pharmacol Res 2020; 156:104777. [PMID: 32244027 DOI: 10.1016/j.phrs.2020.104777] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/04/2020] [Accepted: 03/23/2020] [Indexed: 02/07/2023]
Abstract
Circular RNAs (circRNAs) are single-stranded RNAs which form a covalent bond structure without a 5' cap or a 3' polyadenylated tail, which is deleted through back-splicing. The expression of circRNAs in highly divergent eukaryotes is abundant. With the development of high-throughput sequencing, the mysteries of circRNAs have gradually been revealed. Increased attention has been paid to determining their biological functions and whether their changed expression profiles are linked to disease progression. Functionally, circRNAs have been shown to act as miRNA sponges or nuclear transcription factor regulators, and to play a part in RNA splicing. Various types of circRNAs have been discovered to be differentially expressed under steady physiological and pathological conditions. Recently, several studies have focused on the roles of circRNAs in macrophages on inflammatory stimulation. In this study, we review the current advances in the understanding of circRNAs in macrophages under various pathological conditions, in particular during organ fibrosis, and summarize possible directions for future circRNA applications.
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Affiliation(s)
- Mengxue Xu
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, China; Department of Immunology, Jiangsu Key Laboratory of Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Feiting Xie
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, China; Department of Immunology, Jiangsu Key Laboratory of Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Xinyi Tang
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, China.
| | - Tingting Wang
- Department of Laboratory Medicine, Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi Children's Hospital, Wuxi, China.
| | - Shengjun Wang
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, China; Department of Immunology, Jiangsu Key Laboratory of Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, China.
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15
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Therapeutic effects of the PKR inhibitor C16 suppressing tumor proliferation and angiogenesis in hepatocellular carcinoma in vitro and in vivo. Sci Rep 2020; 10:5133. [PMID: 32198380 PMCID: PMC7083831 DOI: 10.1038/s41598-020-61579-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/21/2020] [Indexed: 11/12/2022] Open
Abstract
The therapeutic effects of C16, which is an inhibitor of RNA-dependent protein kinase (PKR), on growth of hepatocellular carcinoma (HCC) cells and tumor progression in vitro and in vivo were evaluated. Huh7 cells, a human HCC cell line, were used. The effects of C16 on cell viability were evaluated with the MTT assay, and real-time RT-PCR was performed. Huh7 cells were grafted into immunodeficient mice, and the in vivo effects of C16 on tumorigenesis were examined. C16 suppressed proliferation of HCC cells in a dose-dependent manner in vitro. Mouse models with xenograft transplantation showed that the inhibitor suppressed the growth of HCC cells in vivo. Moreover, C16 decreased angiogenesis in HCC tissue in the xenograft model. Consistent with these results in mice, transcript levels of vascular endothelial growth factor-A and factor-B, platelet-derived growth factor-A and factor-B, fibroblast growth factor-2, epidermal growth factor, and hepatocyte growth factor, which are angiogenesis-related growth factors, were significantly decreased by C16 in vitro. In conclusion, the PKR inhibitor C16 blocked tumor cell growth and angiogenesis via a decrease in mRNA levels of several growth factors. C16 may be useful in the treatment of HCC.
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16
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Hood IV, Gordon JM, Bou-Nader C, Henderson FE, Bahmanjah S, Zhang J. Crystal structure of an adenovirus virus-associated RNA. Nat Commun 2019; 10:2871. [PMID: 31253805 PMCID: PMC6599070 DOI: 10.1038/s41467-019-10752-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/27/2019] [Indexed: 12/20/2022] Open
Abstract
Adenovirus Virus-Associated (VA) RNAs are the first discovered viral noncoding RNAs. By mimicking double-stranded RNAs (dsRNAs), the exceptionally abundant, multifunctional VA RNAs sabotage host machineries that sense, transport, process, or edit dsRNAs. How VA-I suppresses PKR activation despite its strong dsRNA character, and inhibits the crucial antiviral kinase to promote viral translation, remains largely unknown. Here, we report a 2.7 Å crystal structure of VA-I RNA. The acutely bent VA-I features an unusually structured apical loop, a wobble-enriched, coaxially stacked apical and tetra-stems necessary and sufficient for PKR inhibition, and a central domain pseudoknot that resembles codon-anticodon interactions and prevents PKR activation by VA-I. These global and local structural features collectively define VA-I as an archetypal PKR inhibitor made of RNA. The study provides molecular insights into how viruses circumnavigate cellular rules of self vs non-self RNAs to not only escape, but further compromise host innate immunity.
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Affiliation(s)
- Iris V Hood
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Jackson M Gordon
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Frances E Henderson
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Soheila Bahmanjah
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA.
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17
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Piazzi M, Bavelloni A, Gallo A, Faenza I, Blalock WL. Signal Transduction in Ribosome Biogenesis: A Recipe to Avoid Disaster. Int J Mol Sci 2019; 20:ijms20112718. [PMID: 31163577 PMCID: PMC6600399 DOI: 10.3390/ijms20112718] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/29/2019] [Accepted: 05/30/2019] [Indexed: 12/27/2022] Open
Abstract
Energetically speaking, ribosome biogenesis is by far the most costly process of the cell and, therefore, must be highly regulated in order to avoid unnecessary energy expenditure. Not only must ribosomal RNA (rRNA) synthesis, ribosomal protein (RP) transcription, translation, and nuclear import, as well as ribosome assembly, be tightly controlled, these events must be coordinated with other cellular events, such as cell division and differentiation. In addition, ribosome biogenesis must respond rapidly to environmental cues mediated by internal and cell surface receptors, or stress (oxidative stress, DNA damage, amino acid depletion, etc.). This review examines some of the well-studied pathways known to control ribosome biogenesis (PI3K-AKT-mTOR, RB-p53, MYC) and how they may interact with some of the less well studied pathways (eIF2α kinase and RNA editing/splicing) in higher eukaryotes to regulate ribosome biogenesis, assembly, and protein translation in a dynamic manner.
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Affiliation(s)
- Manuela Piazzi
- Istituto di Genetica Molecolare-Luigi Luca Cavalli Sforza, UOS Bologna, Consiglio Nazionale delle Ricerche (IGM-CNR), 40136 Bologna, Italy.
- IRCCS, Istituto Ortopedico Rizzoli, 40136 Bologna, Italy.
| | | | - Angela Gallo
- RNA Editing Laboratory, Dipartimento di Oncoematologia, IRCCS, Ospedale Pediatrica Bambino Gesù, 00146 Rome, Italy.
| | - Irene Faenza
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, 40126 Bologna, Italy.
| | - William L Blalock
- Istituto di Genetica Molecolare-Luigi Luca Cavalli Sforza, UOS Bologna, Consiglio Nazionale delle Ricerche (IGM-CNR), 40136 Bologna, Italy.
- IRCCS, Istituto Ortopedico Rizzoli, 40136 Bologna, Italy.
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18
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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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19
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Hirata Y, Iwasaki T, Makimura Y, Okajima S, Oh-Hashi K, Takemori H. Inhibition of double-stranded RNA-dependent protein kinase prevents oxytosis and ferroptosis in mouse hippocampal HT22 cells. Toxicology 2019; 418:1-10. [PMID: 30817950 DOI: 10.1016/j.tox.2019.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/26/2019] [Accepted: 02/22/2019] [Indexed: 01/20/2023]
Abstract
Double-stranded RNA-dependent protein kinase (PKR) is a component of signal transduction pathways mediating various stress signals including oxidative stress and endoplasmic reticulum (ER) stress and is suggested to be implicated in several neurodegenerative diseases. Cell death in neurodegenerative conditions has been linked to oxidative stress; however, the involvement of PKR in endogenous oxidative stress such as oxytosis and ferroptosis which is quite distinct from classical apoptosis remains unknown. We investigated here the effect of a PKR inhibitor C16 (an imidazole-oxindole derivative) on oxytosis and ferroptosis in cultured HT22 mouse hippocampal cells. C16 prevented glutamate- and erastin-induced cell death, reactive oxygen species accumulation, Ca2+ influx, phosphorylation of inositol-requiring enzyme 1 (IRE1), one of the three branches of ER stress signaling and its downstream signaling components. On the other hand, C16 did not prevent oxidative stress-induced heme oxygenase-1 expression; instead, C16 activated the extracellular signal-regulated kinase pathway. The protective effect of C16 is diminished in PKR knockout HT22 cells. Real time measurements of the oxygen consumption rate and extracellular acidification rate over a long period of time leading to cell death showed that C16 partially prevented erastin-induced mitochondrial and glycolytic dysfunction. These results suggest that PKR is an important component of oxytosis and ferroptosis and the inhibition of PKR is neuroprotective against endogenous oxidative stress-induced cell death and provide an effective strategy for neuroprotection.
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Affiliation(s)
- Yoko Hirata
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan; United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido, Gifu 501-1193, Japan.
| | - Takuya Iwasaki
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan
| | - Yukimi Makimura
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan
| | - Sayaka Okajima
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan
| | - Kentaro Oh-Hashi
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan; United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido, Gifu 501-1193, Japan
| | - Hiroshi Takemori
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan; United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido, Gifu 501-1193, Japan.
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20
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Lee KS, Shin S, Cho E, Im WK, Jeon SH, Kim Y, Park D, Fréchet M, Chajra H, Jung E. nc886, a non-coding RNA, inhibits UVB-induced MMP-9 and COX-2 expression via the PKR pathway in human keratinocytes. Biochem Biophys Res Commun 2019; 512:647-652. [PMID: 30685091 DOI: 10.1016/j.bbrc.2019.01.068] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 01/14/2019] [Indexed: 01/30/2023]
Abstract
nc886, a long non-coding RNA (ncRNA) of 101 nucleotides in length, is known as a vault RNA or microRNA precursor. Despite the recent discovery that ncRNAs in the nucleus play a crucial role in regulating chromosomal transformation and transcription, only a few studies have focused on the function of ncRNAs in the cytoplasm, such as nc886. Several studies have investigated the function of nc886 as a suppressor of carcinogenesis and inflammation in different cancer cell types; however, its role in the skin has yet to be clearly elucidated. The two RNA binding sites for protein kinase RNA-activated (PKR) are located in the central region of the stable structure of nc886, which competes with other double-stranded RNA species. Successful binding results in decreased PKR activity. Among changes in skin cells induced by ultraviolet B (UVB) radiation, nc886 expression decreases, whereas PKR phosphorylation via mitogen-activated protein kinases (MAPKs) increases. Reduced nc886 expression leads to uncontrolled PKR activity and increases in the expression of inflammatory cytokines, matrix metalloproteinase-9 (MMP-9), type IV collagenase, and cyclooxygenase (COX-2), which ultimately accelerate inflammatory responses and skin aging. The present study investigated the regulatory mechanism associated with PKR activity and nc886-PKR binding in skin cell aging and inflammation. These results suggest a role for nc886 in controlling photoaging and inflammation in skin cells.
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Affiliation(s)
- Kwang-Soo Lee
- Life Science Institute, Biospectrum, Yongin, Gyeonggi, South Korea
| | - Seoungwoo Shin
- Life Science Institute, Biospectrum, Yongin, Gyeonggi, South Korea
| | - Eunae Cho
- Life Science Institute, Biospectrum, Yongin, Gyeonggi, South Korea
| | - Won Kyun Im
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Gyeonggi, South Korea; Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon, Gangwon, South Korea
| | - Sung Ho Jeon
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon, Gangwon, South Korea
| | - Younghyun Kim
- Life Science Institute, Biospectrum, Yongin, Gyeonggi, South Korea
| | - Deokhoon Park
- Life Science Institute, Biospectrum, Yongin, Gyeonggi, South Korea
| | | | - Hanane Chajra
- Clariant Active Ingredients, d'espagne, Toulouse, France
| | - Eunsun Jung
- Life Science Institute, Biospectrum, Yongin, Gyeonggi, South Korea.
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21
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Golec E, Lind L, Qayyum M, Blom AM, King BC. The Noncoding RNA nc886 Regulates PKR Signaling and Cytokine Production in Human Cells. THE JOURNAL OF IMMUNOLOGY 2018; 202:131-141. [PMID: 30518569 DOI: 10.4049/jimmunol.1701234] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 10/29/2018] [Indexed: 12/17/2022]
Abstract
Protein kinase RNA-activated (PKR) is a cytoplasmic receptor for dsRNA, and as such is involved in detection of viral infection. On binding dsRNA, PKR dimerizes, autophosphorylates, and then phosphorylates its substrate, eukaryotic translation initiation factor 2 subunit α (eIF2α), causing inhibition of mRNA translation and shutdown of viral protein production. However, active PKR has also been found to be involved in the NF-κB signaling pathway by inducing phosphorylation of IκBα. PKR is regulated by the noncoding RNA nc886, which has altered expression in cancer. We have found that expression of nc886 is highly upregulated during activation of human CD4+ T cells. As has been described in other cell types, nc886 bound to PKR in human T cell lysates, preventing PKR phosphorylation by polyinosinic:polycytidylic acid or HIV trans-activation response element RNA in lysates of T cell lines or primary human CD4+ T cells. Using clonal human T cell lines, we found that nc886 expression was strictly required for IFN-γ and IL-2 expression and secretion after T cell activation but did not affect proliferation or activation-induced cell death. In stimulated human PBMCs, nc886 expression strongly correlated with IFN-γ expression. Although nc886 inhibited PKR activation by dsRNA, it was required for PKR phosphorylation during T cell stimulation, with subsequent NF-κB signaling and CREB phosphorylation. nc886 also regulated PKR phosphorylation during human monocyte-derived macrophage activation. We have therefore identified nc886 as a noncoding RNA marker of T cell activation and regulator of PKR-dependent signaling.
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Affiliation(s)
- Ewelina Golec
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 21428 Malmö, Sweden
| | - Liza Lind
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 21428 Malmö, Sweden
| | - Munazza Qayyum
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 21428 Malmö, Sweden
| | - Anna M Blom
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 21428 Malmö, Sweden
| | - Ben C King
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 21428 Malmö, Sweden
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Binding of eEF1A2 to the RNA-dependent protein kinase PKR modulates its activity and promotes tumour cell survival. Br J Cancer 2018; 119:1410-1420. [PMID: 30420615 PMCID: PMC6265344 DOI: 10.1038/s41416-018-0336-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 10/24/2018] [Indexed: 11/26/2022] Open
Abstract
Background Through several not-fully-characterised moonlighting functions, translation elongation factor eEF1A2 is known to provide a fitness boost to cancer cells. Furthermore, eEF1A2 has been demonstrated to confer neoplastic characteristics on preneoplastic, nontumourigenic precursor cells. We have previously shown that eEF1A2 is the target of plitidepsin, a marine drug currently in development for cancer treatment. Herein, we characterised a new signalling pathway through which eEF1A2 promotes tumour cell survival. Methods Previously unknown binding partners of eEF1A2 were identified through co-immunoprecipitation, high-performance liquid chromatography-mass spectrometry and proximity ligation assay. Using plitidepsin to release eEF1A2 from those protein complexes, their effects on cancer cell survival were analysed in vitro. Results We uncovered that double-stranded RNA-activated protein kinase (PKR) is a novel eEF1A2-interacting partner whose pro-apoptotic effect is hindered by the translation factor, most likely through sequestration and inhibition of its kinase activity. Targeting eEF1A2 with plitidepsin releases PKR from the complex, facilitating its activation and triggering a mitogen-activated protein kinase signalling cascade together with a nuclear factor-κB-dependent activation of the extrinsic apoptotic pathway, which lead to tumour cell death. Conclusions Through its binding to PKR, eEF1A2 provides a survival boost to cancer cells, constituting an Achilles heel that can be exploited in anticancer therapy.
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Mangali S, Bhat A, Udumula MP, Dhar I, Sriram D, Dhar A. Inhibition of protein kinase R protects against palmitic acid-induced inflammation, oxidative stress, and apoptosis through the JNK/NF-kB/NLRP3 pathway in cultured H9C2 cardiomyocytes. J Cell Biochem 2018; 120:3651-3663. [PMID: 30259999 DOI: 10.1002/jcb.27643] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 08/14/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND PURPOSE Double-stranded RNA-dependent protein kinase (PKR) is a critical regulator of apoptosis, oxidative stress, and inflammation under hyperlipidemic and insulin resistance conditions. Saturated free fatty acids, such as palmitic acid (PA), are known inducers of apoptosis in numerous cell types. However, the underlying molecular mechanism is not fully understood. The aim of the present study was to examine the effect of PA on cultured rat H9C2 cardiac myocytes cells and to investigate the PKR mediated harmful effects of PA in vitro in cultured cardiomyocytes. EXPERIMENTAL APPROACH PKR expression was determined by immunofluorescence and immunoblotting. Oxidative stress and apoptosis were determined by flow cytometry and assay kits. The expression of different gene markers of apoptosis, oxidative stress, and inflammation were measured by Western blot analysis and reverse transcription polymerase chain reaction. KEY RESULTS PKR expression, reactive oxygen species levels as well as apoptosis were increased in PA-treated cultured H9C2 cardiomyocytes. The harmful effects of PA were attenuated by a selective PKR inhibitor, C16. Moreover, we observed that upregulation of c-Jun N-terminal kinase (JNK), nuclear factor-kB (NF-kB) and NACHT, LRR and PYD domains-containing protein 3 (NLRP3) pathways is associated with increased expression of interleukin 6 and tumor necrosis factor-α in PA-treated cardiomyocytes and attenuation by a selective PKR inhibitor. CONCLUSION AND IMPLICATIONS Our study reports, for the first time, that PKR-mediated harmful effects of PA in cultured cardiomyocytes via activation of JNK, NF-kB, and NLRP3 pathways. Inhibition of PKR is one of the possible mechanistic approaches to inhibit inflammation, oxidative stress, and apoptosis in lipotoxicity-induced cardiomyocyte damage.
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Affiliation(s)
- Sureshbabu Mangali
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad, Telangana, India
| | - Audesh Bhat
- Department of Molecular Biology, Central University of Jammu, Jammu and Kashmir, India
| | - Mary Priyanka Udumula
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad, Telangana, India
| | - Indu Dhar
- Department of Clinical Sciences, University of Bergen, Bergen, Norway
| | - Dharmarajan Sriram
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad, Telangana, India
| | - Arti Dhar
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad, Telangana, India
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PKR Senses Nuclear and Mitochondrial Signals by Interacting with Endogenous Double-Stranded RNAs. Mol Cell 2018; 71:1051-1063.e6. [PMID: 30174290 DOI: 10.1016/j.molcel.2018.07.029] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/14/2018] [Accepted: 07/23/2018] [Indexed: 01/08/2023]
Abstract
Protein kinase RNA-activated (PKR) induces immune response by sensing viral double-stranded RNAs (dsRNAs). However, growing evidence suggests that PKR can also be activated by endogenously expressed dsRNAs. Here, we capture these dsRNAs by formaldehyde-mediated crosslinking and immunoprecipitation sequencing and find that various noncoding RNAs interact with PKR. Surprisingly, the majority of the PKR-interacting RNA repertoire is occupied by mitochondrial RNAs (mtRNAs). MtRNAs can form intermolecular dsRNAs owing to bidirectional transcription of the mitochondrial genome and regulate PKR and eIF2α phosphorylation to control cell signaling and translation. Moreover, PKR activation by mtRNAs is counteracted by PKR phosphatases, disruption of which causes apoptosis from PKR overactivation even in uninfected cells. Our work unveils dynamic regulation of PKR even without infection and establishes PKR as a sensor for nuclear and mitochondrial signaling cues in regulating cellular metabolism.
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Taga M, Mouton-Liger F, Sadoune M, Gourmaud S, Norman J, Tible M, Thomasseau S, Paquet C, Nicoll JAR, Boche D, Hugon J. PKR modulates abnormal brain signaling in experimental obesity. PLoS One 2018; 13:e0196983. [PMID: 29795582 PMCID: PMC5968403 DOI: 10.1371/journal.pone.0196983] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 04/24/2018] [Indexed: 12/21/2022] Open
Abstract
Metabolic disorders including obesity and type 2 diabetes are known to be associated with chronic inflammation and are obvious risk factors for Alzheimer's disease. Recent evidences concerning obesity and diabetes suggest that the metabolic inflammasome ("metaflammasome") mediates chronic inflammation. The double-stranded RNA-dependent protein kinase (PKR) is a central component of the metaflammasome. In wild type (WT) and PKR-/- mice, blood glucose, insulin and lipid levels and the brain expression of the phosphorylated components of the metaflammasome-PKR, JNK, IRS1 and IKKbeta-were studied after the induction of obesity by a high fat diet (HFD). The results showed significant increased levels of activated brain metaflammasome proteins in exposed WT mice but the changes were not significant in PKR-/- mice. In addition, gain weight was observed in WT mice and also in PKR-/- mice exposed to HFD. Increased blood insulin level was more accentuated in PKR -/- mice. The modulation of PKR activity could be an appropriate therapeutic approach, aimed at reducing abnormal brain metabolism and inflammation linked to metabolic disorders in order to reduce the risk of neurodegeneration.
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Affiliation(s)
- Mariko Taga
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- INSERM Units U942, Paris, France
| | | | | | | | - Jenny Norman
- Histochemistry Research Unit, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | | | | | - Claire Paquet
- INSERM Units U942, Paris, France
- Center of Cognitive Neurology Lariboisière Hospital, APHP, University Paris Diderot, Paris, France
| | - James A. R. Nicoll
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- Department of Cellular Pathology, University Hospital Southampton NHS Foundation Trust, Southampton, Southampton, United Kingdom
| | - Delphine Boche
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Jacques Hugon
- INSERM Units U942, Paris, France
- Center of Cognitive Neurology Lariboisière Hospital, APHP, University Paris Diderot, Paris, France
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Exacerbated Apoptosis of Cells Infected with Infectious Bursal Disease Virus upon Exposure to Interferon Alpha. J Virol 2018. [PMID: 29540594 DOI: 10.1128/jvi.00364-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Infectious bursal disease virus (IBDV) belongs to the Birnaviridae family and is the etiological agent of a highly contagious and immunosuppressive disease (IBD) that affects domestic chickens (Gallus gallus). IBD or Gumboro disease leads to high rates of morbidity and mortality of infected animals and is responsible for major economic losses to the poultry industry worldwide. IBD is characterized by a massive loss of IgM-bearing B lymphocytes and the destruction of the bursa of Fabricius. The molecular bases of IBDV pathogenicity are still poorly understood; nonetheless, an exacerbated cytokine immune response and B cell depletion due to apoptosis are considered main factors that contribute to the severity of the disease. Here we have studied the role of type I interferon (IFN) in IBDV infection. While IFN pretreatment confers protection against subsequent IBDV infection, the addition of IFN to infected cell cultures early after infection drives massive apoptotic cell death. Downregulation of double-stranded RNA (dsRNA)-dependent protein kinase (PKR), tumor necrosis factor alpha (TNF-α), or nuclear factor κB (NF-κB) expression drastically reduces the extent of apoptosis, indicating that they are critical proteins in the apoptotic response induced by IBDV upon treatment with IFN-α. Our results indicate that IBDV genomic dsRNA is a major viral factor that contributes to the triggering of apoptosis. These findings provide novel insights into the potential mechanisms of IBDV-induced immunosuppression and pathogenesis in chickens.IMPORTANCE IBDV infection represents an important threat to the poultry industry worldwide. IBDV-infected chickens develop severe immunosuppression, which renders them highly susceptible to secondary infections and unresponsive to vaccination against other pathogens. The early dysregulation of the innate immune response led by IBDV infection and the exacerbated apoptosis of B cells have been proposed as the main factors that contribute to virus-induced immunopathogenesis. Our work contributes for the first time to elucidating a potential mechanism driving the apoptotic death of IBDV-infected cells upon exposure to type I IFN. We provide solid evidence about the critical importance of PKR, TNF-α, and NF-κB in this phenomenon. The described mechanism could facilitate the early clearance of infected cells, thereby aiding in the amelioration of IBDV-induced pathogenesis, but it could also contribute to B cell depletion and immunosuppression. The balance between these two opposing effects might be dramatically affected by the genetic backgrounds of both the host and the infecting virus strain.
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Watanabe T, Imamura T, Hiasa Y. Roles of protein kinase R in cancer: Potential as a therapeutic target. Cancer Sci 2018; 109:919-925. [PMID: 29478262 PMCID: PMC5891186 DOI: 10.1111/cas.13551] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 02/15/2018] [Accepted: 02/17/2018] [Indexed: 01/13/2023] Open
Abstract
Double‐stranded (ds) RNA‐dependent protein kinase (PKR) is a ubiquitously expressed serine/threonine protein kinase. It was initially identified as an innate immune antiviral protein induced by interferon (IFN) and activated by dsRNA. PKR is recognized as a key executor of antiviral host defense. Moreover, it contributes to inflammation and immune regulation through several signaling pathways. In addition to IFN and dsRNA, PKR is activated by multiple stimuli and regulates various signaling pathways including the mitogen‐activated protein kinase (MAPK) and nuclear factor kappa‐light‐chain‐enhancer of activated B cells pathways. PKR was initially thought to be a tumor suppressor as a result of its ability to suppress cell growth and interact with major tumor suppressor genes. However, in several types of malignant disease, such as colon and breast cancers, its role remains controversial. In hepatocellular carcinoma, hepatitis C virus (HCV) is the main cause of liver cancer, and PKR inhibits HCV replication, indicating its role as a tumor suppressor. However, PKR is overexpressed in cirrhotic patients, and acts as a tumor promoter through enhancement of cancer cell growth by mediating MAPK or signal transducer and activator of transcription pathways. Moreover, PKR is reportedly required for the activation of inflammasomes and influences metabolic disorders. In the present review, we introduce the multifaceted roles of PKR such as antiviral function, tumor cell growth, regulation of inflammatory immune responses, and maintaining metabolic homeostasis; and discuss future perspectives on PKR biology including its potential as a therapeutic target for liver cancer.
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Affiliation(s)
- Takao Watanabe
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Toon, Japan
| | - Takeshi Imamura
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Toon, Ehime, Japan.,Translational Research Center, Ehime University Hospital, Toon, Japan
| | - Yoichi Hiasa
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Toon, Japan
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ADAR1 is targeted by miR-143 to regulate IL-1β-induced endothelial activation through the NFκB pathway. Int J Biochem Cell Biol 2017; 89:25-33. [DOI: 10.1016/j.biocel.2017.05.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/10/2017] [Accepted: 05/15/2017] [Indexed: 11/15/2022]
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29
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Udumula MP, Babu MS, Bhat A, Dhar I, Sriram D, Dhar A. High glucose impairs insulin signaling via activation of PKR pathway in L6 muscle cells. Biochem Biophys Res Commun 2017; 486:645-651. [DOI: 10.1016/j.bbrc.2017.03.078] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 03/16/2017] [Indexed: 02/06/2023]
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30
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Allen L, Buckner A, Buckner CA, Cano P, Lafrenie RM. Uncaria tomentosa (Willd. ex Schult.) DC (Rubiaceae) Sensitizes THP-1 Cells to Radiation-induced Cell Death. Pharmacognosy Res 2017; 9:221-229. [PMID: 28827961 PMCID: PMC5541476 DOI: 10.4103/pr.pr_83_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Background: Uncaria tomentosa (Willd. ex Schult.) DC (Rubiaceae), known as Cat's Claw or Uña de gato, is a traditionally used medicinal plant native to Peru. Some studies have shown that U. tomentosa can act as an antiapoptotic agent and enhance DNA repair in chemotherapy-treated cells although others have shown that U. tomentosa enhanced apoptosis. Objective: To determine if treatment with U. tomentosa can significantly enhance cell death in THP-1 cells exposed to ionizing radiation. Materials and Methods: THP-1 monocyte-like cells were treated with ethanolic extracts of U. tomentosa in the presence or absence of bacterial lipopolysaccharide and then exposed to ionizing radiation. Cell proliferation was assessed by MTT and clonogenic assays and the effects on cell cycle measured by flow cytometry and immunoblotting. Changes in cell signaling were determined by immunoblotting and cytokine ELISA and activation of apoptosis measured by caspase activation and DNA fragmentation analysis. Results: Treatment of THP-1 cells with U. tomentosa had a small effect on cell proliferation. However, when the U. tomentosa-pretreated cells were also subjected to 5–9 Gy ionizing radiation, they showed a significant decrease in cell proliferation and increased cellular apoptosis as measured by DNA fragmentation and caspase activation. Treatment with U. tomentosa also decreased the expression of Cyclin E and Cyclin B, key regulators of normal cell cycle progression, and decreased the phosphorylation of various stress-activated, cell survival proteins including p38, ERK, and SAP/JNK kinase. Conclusions: These results suggest that U. tomentosa could be useful in enhancing cell death following anticancer therapies including ionizing radiation. SUMMARY Treatment of THP-1 cells with Uncaria tomentosa increases their susceptibility to X-rays. The combination of Uncaria tomentosa and X-ray exposure strongly inhibits cell signaling and promotes apoptosis.
Abbreviations Used: LPS: Lipopolysaccharide, TNF: Tumor necrosis factor: IL-1, Interleukin-1: SDS: Sodium dodecylsulphate, TBS: Tris-buffered saline.
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Affiliation(s)
- Lisa Allen
- Program in Biomolecular Science, Laurentian University, Sudbury, ON P3E 2C6, Canada.,Health Sciences North, Sudbury, ON P3E 5J1, Canada
| | - Alison Buckner
- Program in Biomolecular Science, Laurentian University, Sudbury, ON P3E 2C6, Canada.,Health Sciences North, Sudbury, ON P3E 5J1, Canada
| | - Carly A Buckner
- Program in Biomolecular Science, Laurentian University, Sudbury, ON P3E 2C6, Canada.,Health Sciences North, Sudbury, ON P3E 5J1, Canada
| | - Pablo Cano
- Health Sciences North, Sudbury, ON P3E 5J1, Canada
| | - Robert M Lafrenie
- Program in Biomolecular Science, Laurentian University, Sudbury, ON P3E 2C6, Canada.,Health Sciences North, Sudbury, ON P3E 5J1, Canada.,Division of Medical Science, Northern Ontario School of Medicine, Sudbury, ON P3E 2C6, Canada.,Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada
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31
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Roles of PKR in differentiation and apoptosis of bone-related cells. Anat Sci Int 2016; 92:313-319. [DOI: 10.1007/s12565-016-0385-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/25/2016] [Indexed: 12/13/2022]
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Wang Y, Men M, Xie B, Shan J, Wang C, Liu J, Zheng H, Yang W, Xue S, Guo C. Inhibition of PKR protects against H 2O 2-induced injury on neonatal cardiac myocytes by attenuating apoptosis and inflammation. Sci Rep 2016; 6:38753. [PMID: 27929137 PMCID: PMC5144063 DOI: 10.1038/srep38753] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 11/14/2016] [Indexed: 12/13/2022] Open
Abstract
Reactive oxygenation species (ROS) generated from reperfusion results in cardiac injury through apoptosis and inflammation, while PKR has the ability to promote apoptosis and inflammation. The aim of the study was to investigate whether PKR is involved in hydrogen peroxide (H2O2) induced neonatal cardiac myocytes (NCM) injury. In our study, NCM, when exposed to H2O2, resulted in persistent activation of PKR due to NCM endogenous RNA. Inhibition of PKR by 2-aminopurine (2-AP) or siRNA protected against H2O2 induced apoptosis and injury. To elucidate the mechanism, we revealed that inhibition of PKR alleviated H2O2 induced apoptosis companied by decreased caspase3/7 activity, BAX and caspase-3 expression. We also revealed that inhibition of PKR suppressed H2O2 induced NFκB pathway and NLRP3 activation. Finally, we found ADAR1 mRNA and protein expression were both induced after H2O2 treatment through STAT-2 dependent pathway. By gain and loss of ADAR1 expression, we confirmed ADAR1 modulated PKR activity. Therefore, we concluded inhibition of PKR protected against H2O2-induced injury by attenuating apoptosis and inflammation. A self-preservation mechanism existed in NCM that ADAR1 expression is induced by H2O2 to limit PKR activation simultaneously. These findings identify a novel role for PKR/ADAR1 in myocardial reperfusion injury.
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Affiliation(s)
- Yongyi Wang
- Department of Cardiovascular Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Min Men
- Department of endocrinology, Xi'an Central Hospital, Shaanxi, China
| | - Bo Xie
- Department of Cardiovascular Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jianggui Shan
- Department of Cardiovascular Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chengxi Wang
- Department of Cardiovascular Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jidong Liu
- Department of Cardiovascular Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Hui Zheng
- Department of Cardiovascular Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Wengang Yang
- Department of Cardiovascular Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Song Xue
- Department of Cardiovascular Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Changfa Guo
- Department of Cardiovascular Surgery, Zhong Shan Hospital, School of Medicine, Fudan University, Shanghai, China
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Bravo Cruz AG, Shisler JL. Vaccinia virus K1 ankyrin repeat protein inhibits NF-κB activation by preventing RelA acetylation. J Gen Virol 2016; 97:2691-2702. [DOI: 10.1099/jgv.0.000576] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Ariana G. Bravo Cruz
- Department of Microbiology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL 61801, USA
| | - Joanna L. Shisler
- Department of Microbiology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL 61801, USA
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Ertunc ME, Hotamisligil GS. Lipid signaling and lipotoxicity in metaflammation: indications for metabolic disease pathogenesis and treatment. J Lipid Res 2016; 57:2099-2114. [PMID: 27330055 DOI: 10.1194/jlr.r066514] [Citation(s) in RCA: 303] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 06/20/2016] [Indexed: 12/19/2022] Open
Abstract
Lipids encompass a wide variety of molecules such as fatty acids, sterols, phospholipids, and triglycerides. These molecules represent a highly efficient energy resource and can act as structural elements of membranes or as signaling molecules that regulate metabolic homeostasis through many mechanisms. Cells possess an integrated set of response systems to adapt to stresses such as those imposed by nutrient fluctuations during feeding-fasting cycles. While lipids are pivotal for these homeostatic processes, they can also contribute to detrimental metabolic outcomes. When metabolic stress becomes chronic and adaptive mechanisms are overwhelmed, as occurs during prolonged nutrient excess or obesity, lipid influx can exceed the adipose tissue storage capacity and result in accumulation of harmful lipid species at ectopic sites such as liver and muscle. As lipid metabolism and immune responses are highly integrated, accumulation of harmful lipids or generation of signaling intermediates can interfere with immune regulation in multiple tissues, causing a vicious cycle of immune-metabolic dysregulation. In this review, we summarize the role of lipotoxicity in metaflammation at the molecular and tissue level, describe the significance of anti-inflammatory lipids in metabolic homeostasis, and discuss the potential of therapeutic approaches targeting pathways at the intersection of lipid metabolism and immune function.
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Affiliation(s)
- Meric Erikci Ertunc
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard T. H. Chan School of Public Health, Broad Institute of Harvard and Massachusetts Institute of Technology, Boston, MA 02115
| | - Gökhan S Hotamisligil
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard T. H. Chan School of Public Health, Broad Institute of Harvard and Massachusetts Institute of Technology, Boston, MA 02115
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Shinohara H, Teramachi J, Okamura H, Yang D, Nagata T, Haneji T. Double Stranded RNA-Dependent Protein Kinase is Necessary for TNF-α-Induced Osteoclast Formation In Vitro and In Vivo. J Cell Biochem 2016; 116:1957-67. [PMID: 25739386 DOI: 10.1002/jcb.25151] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 02/27/2015] [Indexed: 12/12/2022]
Abstract
Double-stranded RNA-dependent protein kinase (PKR) is involved in cell cycle progression, cell proliferation, cell differentiation, tumorgenesis, and apoptosis. We previously reported that PKR is required for differentiation and calcification in osteoblasts. TNF-α plays a key role in osteoclast differentiation. However, it is unknown about the roles of PKR in the TNF-α-induced osteoclast differentiation. The expression of PKR in osteoclast precursor RAW264.7 cells increased during TNF-α-induced osteoclastogenesis. The TNF-α-induced osteoclast differentiation in bone marrow-derived macrophages and RAW264.7 cells was markedly suppressed by the pretreatment of PKR inhibitor, 2-aminopurine (2AP), as well as gene silencing of PKR. The expression of gene markers in the differentiated osteoclasts including TRAP, Calcitonin receptor, cathepsin K, and ATP6V0d2 was also suppressed by the 2AP treatment. Bone resorption activity of TNF-α-induced osteoclasts was also supressed by 2AP treatment. Inhibition of PKR supressed the TNF-α-induced activation of NF-κB and MAPK in RAW264.7 cells. 2AP inhibited both the nuclear translocation of NF-κB and its transcriptional activity in RAW264.7 cells. 2AP inhibited the TNF-α-induced expression of NFATc1 and c-fos, master transcription factors in osteoclastogenesis. TNF-α-induced nuclear translocation of NFATc1 in mature osteoclasts was clearly inhibited by the 2AP treatment. The PKR inhibitor C16 decreased the TNF-α-induced osteoclast formation and bone resorption in mouse calvaria. The present study indicates that PKR is necessary for the TNF-α-induced osteoclast differentiation in vitro and in vivo.
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Affiliation(s)
- Hiroki Shinohara
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.,Department of Periodontology and Endodontology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Jumpei Teramachi
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Hirohiko Okamura
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Di Yang
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Toshihiko Nagata
- Department of Periodontology and Endodontology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Tatsuji Haneji
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
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p58(IPK) suppresses NLRP3 inflammasome activation and IL-1β production via inhibition of PKR in macrophages. Sci Rep 2016; 6:25013. [PMID: 27113095 PMCID: PMC4845006 DOI: 10.1038/srep25013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/04/2016] [Indexed: 02/07/2023] Open
Abstract
The NLRP3 inflammasome activation is a key signaling event for activation and secretion of pro-inflammatory cytokines such as IL-1β from macrophages. p58IPK is a molecular chaperone that regulates protein homeostasis through inhibiting eIF-2α kinases including double-stranded RNA–dependent protein kinase (PKR), which has been recently implicated in inflammasome activation. Herein we investigate the role of p58IPK in TLR4 signaling and inflammasome activation in macrophages. Primary bone marrow-derived macrophages (BMDM) was isolated from p58IPK knockout (KO) and wildtype (WT) mice and treated with lipopolysaccharide (LPS) and ATP to activate TLR4 signaling and stimulate inflammasome activation. Compared to WT macrophages, p58IPK deficient cells demonstrated significantly stronger activation of PKR, NF-κB, and JNK and higher expression of pro-inflammatory genes TNF-α and IL-1β. Coincidently, p58IPK deletion intensified NLRP3-inflammasome activation indicated by enhanced caspase 1 cleavage and increased IL-1β maturation and secretion. Pretreatment with specific PKR inhibitor or overexpression of p58IPK largely abolished the changes in inflammasome activation and IL-1β secretion in p58IPK null macrophages. Furthermore, immunoprecipitation assay confirmed the binding of p58IPK with PKR, but not other TLR4 downstream signaling molecules. Collectively, these results suggest a novel and crucial role of p58IPK in regulation of inflammasome activation and IL-1β secretion in macrophages.
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Poon DCH, Ho YS, You R, Tse HL, Chiu K, Chang RCC. PKR deficiency alters E. coli-induced sickness behaviors but does not exacerbate neuroimmune responses or bacterial load. J Neuroinflammation 2015; 12:212. [PMID: 26585788 PMCID: PMC4653925 DOI: 10.1186/s12974-015-0433-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 11/14/2015] [Indexed: 11/15/2022] Open
Abstract
Background Systemic inflammation induces neuroimmune activation, ultimately leading to sickness (e.g., fever, anorexia, motor impairments, exploratory deficits, and social withdrawal). In this study, we evaluated the role of protein kinase R (PKR), a serine-threonine kinase that can control systemic inflammation, on neuroimmune responses and sickness. Methods Wild-type (WT) PKR+/+ mice and PKR−/− mice were subcutaneously injected with live Escherichia coli (E. coli) or vehicle. Food consumption, rotarod test performance, burrowing, open field activity, object investigation, and social interaction were monitored. Plasma TNF-α and corticosterone were measured by ELISA. The percentage of neutrophils in blood was deduced from blood smears. Inflammatory gene expression (IL-1β, TNF-α, IL-6, cyclooxygenase (COX)-2, iNOS) in the liver and the brain (hypothalamus and hippocampus) were quantified by real-time PCR. Blood and lavage fluid (injection site) were collected for microbiological plate count and for real-time PCR of bacterial 16S ribosomal DNA (rDNA). Corticotrophin-releasing hormone (CRH) expression in the hypothalamus was also determined by real-time PCR. Results Deficiency of PKR diminished peripheral inflammatory responses following E. coli challenge. However, while the core components of sickness (anorexia and motor impairments) were similar between both strains of mice, the behavioral components of sickness (reduced burrowing, exploratory activity deficits, and social withdrawal) were only observable in PKR−/− mice but not in WT mice. Such alteration of behavioral components was unlikely to be caused by exaggerated neuroimmune activation, by an impaired host defense to the infection, or due to a dysregulated corticosterone response, because both strains of mice displayed similar neuroimmune responses, bacterial titers, and plasma corticosterone profiles throughout the course of infection. Nevertheless, the induction of hypothalamic corticotrophin-releasing hormone (CRH) by E. coli was delayed in PKR−/− mice relative to WT mice, suggesting that PKR deficiency may postpone the CRH response during systemic inflammation. Conclusions Taken together, our findings show that (1) loss of PKR could alter E. coli-induced sickness behaviors and (2) this was unlikely to be due to exacerbated neuroimmune activation, (3) elevated bacterial load, or (4) dysregulation in the corticosterone response. Further studies can address the role of PKR in the CRH response together with its consequence on sickness.
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Affiliation(s)
- David Chun-Hei Poon
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Yuen-Shan Ho
- School of Nursing, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
| | - Ran You
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Hei-Long Tse
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Kin Chiu
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Raymond Chuen-Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China. .,Research Centre of Heart, Brain, Hormone and Healthy Aging, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China. .,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China. .,Rm. L1-49, Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China.
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Perotti V, Baldassari P, Molla A, Vegetti C, Bersani I, Maurichi A, Santinami M, Anichini A, Mortarini R. NFATc2 is an intrinsic regulator of melanoma dedifferentiation. Oncogene 2015; 35:2862-72. [DOI: 10.1038/onc.2015.355] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 08/04/2015] [Indexed: 12/20/2022]
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39
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He K, Tong D, Zhang S, Cai D, Wang L, Yang Y, Gao L, Chang S, Guo B, Song T, Li A, Huang C. miRNA-99b-3p functions as a potential tumor suppressor by targeting glycogen synthase kinase-3β in oral squamous cell carcinoma Tca-8113 cells. Int J Oncol 2015; 47:1528-36. [PMID: 26315788 DOI: 10.3892/ijo.2015.3135] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/17/2015] [Indexed: 11/06/2022] Open
Abstract
Dysregulation of microRNAs (miRNAs) has been associated with carcinogenesis in oral squamous cell carcinoma (OSCC). In the present study, we investigated the expression and function of miR-99b-3p in human OSCC. We found that the expression levels of miR-99b-3p decreased in 21 clinical OSCC samples (84%). Furthermore, ectopic expression of miR-99b-3p inhibited OSCC cell proliferation by downregulating glycogen synthase kinase-3β (GSK3β), an miR-99b-3p' target gene, at the mRNA and protein levels, both in vitro and in vivo. Moreover, the silencing of GSK3β recapitulated the cellular and molecular effects in a similar manner to the overexpression of miR-99b-3p, which included inhibition of OSCC cell proliferation and suppression of p65 (RelA) and G1 regulators (cyclin D1, CDK4 and CDK6) in vitro. Our data suggest that miR-99b-3p functions as a tumor suppressor in OSCC via GSK3β downregulation.
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Affiliation(s)
- Kang He
- Department of Periodontology, Stomatology Hospital of Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710004, P.R. China
| | - Dongdong Tong
- Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Si Zhang
- Department of Stomatology, First Affiliated Hospital of Xi'an Medical University, Xi'an, Shaanxi 710077, P.R. China
| | - Donghui Cai
- Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Lumin Wang
- Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yang Yang
- Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Ling Gao
- Department of Oral Maxillofacial Surgery, Stomatology Hospital of Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710004, P.R. China
| | - Su'e Chang
- Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Bo Guo
- Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Tusheng Song
- Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Ang Li
- Department of Periodontology, Stomatology Hospital of Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710004, P.R. China
| | - Chen Huang
- Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
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40
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Bahal R, Lakhani P, Bhat A, Kondiparthi L, Dhar I, Desai K, Dhar A. Protein kinase R and the metabolic syndrome. ACTA ACUST UNITED AC 2015. [DOI: 10.3233/jcb-15006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Rishabh Bahal
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet, Hyderabad, Andhra Pradesh, India
| | - Prit Lakhani
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet, Hyderabad, Andhra Pradesh, India
| | - Audesh Bhat
- Department of Microbiology & Immunology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Lavanya Kondiparthi
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet, Hyderabad, Andhra Pradesh, India
| | - Indu Dhar
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Kaushik Desai
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Arti Dhar
- Department of Pharmacy, Birla Institute of Technology and Sciences Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet, Hyderabad, Andhra Pradesh, India
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Nakamura T, Kunz RC, Zhang C, Kimura T, Yuan CL, Baccaro B, Namiki Y, Gygi SP, Hotamisligil GS. A critical role for PKR complexes with TRBP in Immunometabolic regulation and eIF2α phosphorylation in obesity. Cell Rep 2015; 11:295-307. [PMID: 25843719 DOI: 10.1016/j.celrep.2015.03.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 01/14/2015] [Accepted: 03/07/2015] [Indexed: 01/09/2023] Open
Abstract
Aberrant stress and inflammatory responses are key factors in the pathogenesis of obesity and metabolic dysfunction, and the double-stranded RNA-dependent kinase (PKR) has been proposed to play an important role in integrating these pathways. Here, we report the formation of a complex between PKR and TAR RNA-binding protein (TRBP) during metabolic and obesity-induced stress, which is critical for the regulation of eukaryotic translation initiation factor 2 alpha (eIF2α) phosphorylation and c-Jun N-terminal kinase (JNK) activation. We show that TRBP phosphorylation is induced in the setting of metabolic stress, leading to PKR activation. Suppression of hepatic TRBP reduced inflammation, JNK activity, and eIF2α phosphorylation and improved systemic insulin resistance and glucose metabolism, while TRBP overexpression exacerbated the impairment in glucose homeostasis in obese mice. These data indicate that the association between PKR and TRBP integrates metabolism with translational control and inflammatory signaling and plays important roles in metabolic homeostasis and disease.
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Affiliation(s)
- Takahisa Nakamura
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Division of Endocrinology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
| | - Ryan C Kunz
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Cai Zhang
- Division of Endocrinology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Taishi Kimura
- Division of Endocrinology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Celvie L Yuan
- Division of Endocrinology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Brenna Baccaro
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Yuka Namiki
- Biomedicinal Information Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0063, Japan
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Gökhan S Hotamisligil
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard-MIT Broad Institute, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
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42
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Zhu Z, Zhong H, Zhou Q, Hu X, Chen D, Wang J, Wu J, Cai J, Zhou S, Chen AF. Inhibition of PKR impairs angiogenesis through a VEGF pathway. Am J Physiol Endocrinol Metab 2015; 308:E518-24. [PMID: 25587101 DOI: 10.1152/ajpendo.00469.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peripheral artery disease (PAD) is a common clinical problem, and its pathophysiological mechanisms are incompletely understood. Double-stranded RNA-activated protein kinase (PKR) is a ubiquitously expressed serine/threonine protein kinase. Although PKR has been reported in antivirus and the immune system, the role of PKR in vascular function, especially in angiogenesis, is still unclear. PKR(-/-) mice were used in our experiments. Blood flow recovery was significantly delayed in PKR(-/-) vs. WT mice (Laser Doppler detection, n = 9, P < 0.01), accompanied by 34% reduced CD31-positive stain in ischemic muscle 28 days after procedure (immunohistochemistry, n = 9, P < 0.05). PKR expression decreased in the first 12 h and increased to peak at 24 h in human umbilical vein endothelial cells (HUVECs) in response to hypoxia (Western blot analyses, n = 3, P < 0.05). Accordingly, phospho-PKR expression increased in HUVECs 24 h after treatment with hypoxia (Western blot analyses, n = 3, P < 0.05). Inhibition of PKR (siRNA transfection) reduced microtubule formation (Matrigel tube formation, n = 3, vs. control siRNA, P < 0.05) and migration (wound healing, n = 3, vs. control siRNA, P < 0.05) by 33 and 59%, respectively. Vascular endothelial growth factor (VEGF) expression in ischemic muscle from PKR(-/-) mice was significantly decreased by 54% 1 day after procedure (n = 3, P < 0.05, vs. WT) and by 63% 7 days after procedure (n = 3, P < 0.01, vs. WT), respectively. At the same time, VEGF expression in HUVECs decreased by 21% (n = 3, P < 0.05, PKR siRNA vs. control siRNA). These findings demonstrate that PKR mediates angiogenesis through a VEGF pathway, which may form the basis for future intervention of PAD.
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Affiliation(s)
- Zhaowei Zhu
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and
| | - Hua Zhong
- The Third Xiangya Hospital and the College of Pharmacy, Central South University, Changsha, China
| | - Qin Zhou
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and
| | - Xinqun Hu
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and
| | - Dandan Chen
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and
| | - Jiemei Wang
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and
| | - Jinze Wu
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and
| | - Jingjing Cai
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and
| | - Shenghua Zhou
- The Third Xiangya Hospital and the College of Pharmacy, Central South University, Changsha, China
| | - Alex F Chen
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and
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43
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Gao L, Tang W, Ding Z, Wang D, Qi X, Wu H, Guo J. Protein-Binding Function of RNA-Dependent Protein Kinase Promotes Proliferation through TRAF2/RIP1/NF-κB/c-Myc Pathway in Pancreatic β cells. Mol Med 2015; 21:154-66. [PMID: 25715336 DOI: 10.2119/molmed.2014.00235] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 02/18/2015] [Indexed: 12/29/2022] Open
Abstract
Double-stranded RNA-dependent protein kinase (PKR), an intracellular pathogen recognition receptor, is involved both in insulin resistance in peripheral tissues and in downregulation of pancreatic β-cell function in a kinase-dependent manner, indicating PKR as a core component in the progression of type 2 diabetes. PKR also acts as an adaptor protein via its protein-binding domain. Here, the PKR protein-binding function promoted β-cell proliferation without its kinase activity, which is associated with enhanced physical interaction with tumor necrosis factor receptor-associated factor 2 (TRAF2) and TRAF6. In addition, the transcription of the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB)-dependent survival gene c-Myc was upregulated significantly and is necessary for proliferation. Upregulation of the PKR protein-binding function induced the NF-κB pathway, as observed by dose-dependent degradation of IκBα, induced nuclear translocation of p65 and elevated NF-κB-dependent reporter gene expression. NF-κB-dependent reporter activity and β-cell proliferation both were suppressed by TRAF2-siRNA, but not by TRAF6-siRNA. TRAF2-siRNA blocked the ubiquitination of receptor-interacting serine/threonine-protein kinase 1 (RIP1) induced by PKR protein binding. Furthermore, RIP1-siRNA inhibited β-cell proliferation. Proinflammatory cytokines (TNFα) and glucolipitoxicity also promoted the physical interaction of PKR with TRAF2. Collectively, these data indicate a pivotal role for PKR's protein-binding function on the proliferation of pancreatic β cells through TRAF2/RIP1/NF-κB/c-Myc pathways. Therapeutic opportunities for type 2 diabetes may arise when its kinase catalytic function, but not its protein-binding function, is downregulated.
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Affiliation(s)
- Lili Gao
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Wei Tang
- Department of Endocrinology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, People's Republic of China
| | - ZhengZheng Ding
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
| | - DingYu Wang
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
| | - XiaoQiang Qi
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
| | - HuiWen Wu
- Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jun Guo
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
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Kim Y, Yeo J, Lee JH, Cho J, Seo D, Kim JS, Kim VN. Deletion of human tarbp2 reveals cellular microRNA targets and cell-cycle function of TRBP. Cell Rep 2014; 9:1061-74. [PMID: 25437560 DOI: 10.1016/j.celrep.2014.09.039] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/12/2014] [Accepted: 09/22/2014] [Indexed: 12/16/2022] Open
Abstract
TRBP functions as both a Dicer cofactor and a PKR inhibitor. However, the role of TRBP in microRNA (miRNA) biogenesis is controversial and its regulation of PKR in mitosis remains unexplored. Here, we generate TRBP knockout cells and find altered Dicer-processing sites in a subset of miRNAs but no effect on Dicer stability, miRNA abundance, or Argonaute loading. By generating PACT, another Dicer interactor, and TRBP/PACT double knockout (KO) cells, we further show that TRBP and PACT do not functionally compensate for one another and that only TRBP contributes to Dicer processing. We also report that TRBP is hyperphosphorylated by JNK in M phase when PKR is activated by cellular double-stranded RNAs (dsRNAs). Hyperphosphorylation potentiates the inhibitory activity of TRBP on PKR, suppressing PKR in M-G1 transition. By generating human TRBP KO cells, our study clarifies the role of TRBP and unveils negative feedback regulation of PKR through TRBP phosphorylation.
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Affiliation(s)
- Yoosik Kim
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, South Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea
| | - Jinah Yeo
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, South Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea
| | - Jung Hyun Lee
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, South Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea
| | - Jun Cho
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, South Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea
| | - Daekwan Seo
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, South Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea
| | - Jong-Seo Kim
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, South Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea
| | - V Narry Kim
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, South Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea.
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45
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Ferreira ST, Clarke JR, Bomfim TR, De Felice FG. Inflammation, defective insulin signaling, and neuronal dysfunction in Alzheimer's disease. Alzheimers Dement 2014; 10:S76-83. [PMID: 24529528 DOI: 10.1016/j.jalz.2013.12.010] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/05/2013] [Indexed: 02/06/2023]
Abstract
A link between Alzheimer's disease (AD) and metabolic disorders has been established, with patients with type 2 diabetes at increased risk of developing AD and vice versa. The incidence of metabolic disorders, including insulin resistance and type 2 diabetes is increasing at alarming rates worldwide, primarily as a result of poor lifestyle habits. In parallel, as the world population ages, the prevalence of AD, the most common form of dementia in the elderly, also increases. In addition to their epidemiologic and clinical association, mounting recent evidence indicates shared mechanisms of pathogenesis between metabolic disorders and AD. We discuss the concept that peripheral and central nervous system inflammation link the pathogenesis of AD and metabolic diseases. We also explore the contribution of brain inflammation to defective insulin signaling and neuronal dysfunction. Last, we review recent evidence indicating that targeting neuroinflammation may provide novel therapeutic avenues for AD.
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Affiliation(s)
- Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Julia R Clarke
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Theresa R Bomfim
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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Kim Y, Lee JH, Park JE, Cho J, Yi H, Kim VN. PKR is activated by cellular dsRNAs during mitosis and acts as a mitotic regulator. Genes Dev 2014; 28:1310-22. [PMID: 24939934 PMCID: PMC4066401 DOI: 10.1101/gad.242644.114] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
dsRNA-dependent protein kinase R (PKR) plays a key role in innate immunity. PKR binds viral dsRNA and undergoes autophosphorylation, which leads to translational repression and signaling pathway modulation in infected cells. Kim et al. now show that PKR is activated during mitosis in uninfected cells. PKR interacts with dsRNAs formed by inverted Alu repeats, which become accessible to PKR during mitosis. Phosphorylated PKR then suppresses translation and coordinates mitosis. This study unveils a novel function of PKR and endogenous dsRNA mitosis in uninfected cells. dsRNA-dependent protein kinase R (PKR) is a ubiquitously expressed enzyme well known for its roles in immune response. Upon binding to viral dsRNA, PKR undergoes autophosphorylation, and the phosphorylated PKR (pPKR) regulates translation and multiple signaling pathways in infected cells. Here, we found that PKR is activated in uninfected cells, specifically during mitosis, by binding to dsRNAs formed by inverted Alu repeats (IRAlus). While PKR and IRAlu-containing RNAs are segregated in the cytosol and nucleus of interphase cells, respectively, they interact during mitosis when nuclear structure is disrupted. Once phosphorylated, PKR suppresses global translation by phosphorylating the α subunit of eukaryotic initiation factor 2 (eIF2α). In addition, pPKR acts as an upstream kinase for c-Jun N-terminal kinase and regulates the levels of multiple mitotic factors such as CYCLINS A and B and POLO-LIKE KINASE 1 and phosphorylation of HISTONE H3. Disruption of PKR activation via RNAi or expression of a transdominant-negative mutant leads to misregulation of the mitotic factors, delay in mitotic progression, and defects in cytokinesis. Our study unveils a novel function of PKR and endogenous dsRNAs as signaling molecules during the mitosis of uninfected cells.
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Affiliation(s)
- Yoosik Kim
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - Jung Hyun Lee
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - Jong-Eun Park
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - Jun Cho
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - Hyerim Yi
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - V Narry Kim
- Center for RNA Research, Institute for Basic Science, Seoul 151-742, Korea; School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
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47
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Blalock WL, Piazzi M, Bavelloni A, Raffini M, Faenza I, D'Angelo A, Cocco L. Identification of the PKR nuclear interactome reveals roles in ribosome biogenesis, mRNA processing and cell division. J Cell Physiol 2014; 229:1047-60. [PMID: 24347309 DOI: 10.1002/jcp.24529] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 12/05/2013] [Indexed: 01/08/2023]
Abstract
The double-strand RNA-dependent protein kinase, PKR, plays a central role in inflammatory/chronic stress-mediated pathologies such as cancer, diabetes, and neuro/muscular degenerative diseases. Although a significant amount of research has been conducted to elucidate the role of PKR signaling in the cytosol, only recently has attention been paid to the role of PKR in the nuclear compartment. Previously our group reported that phosphorylated forms of PKR are present in the nucleus of acute leukemic cell lines, representing a reservoir of active kinase that responds to stress. Using the CCRF-CEM acute T-cell leukemia cell line, a PKR-specific inhibitor, co-immunoprecipitation and a proteomics approach, which included affinity purified mass spectrometry analysis (AP/MS), we identified the proteins present in active and inactive PKR nuclear complexes. Of the proteins identified in the PKR complexes, sixty-nine (69) were specific to the active complex, while thirty-eight (38) were specific to the inactive complex. An additional thirteen (13) proteins associated specifically with both complexes. The majority of the proteins identified are involved in, ribosome biogenesis, RNA splicing, mRNA stability, gene expression, cell cycle, or chromatin organization, including several with known significance to normal hematopoiesis and/or hematological disease. In agreement with the AP/MS data, basal- or over-expression of PKR under normal growth conditions favored cell proliferation in the tested cell lines, whereas pharmacological inhibition of PKR or shRNA-mediated knock-down did not. PKR was also found to influence the isoform and the level of expression of the proto-oncogene MYC.
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Affiliation(s)
- William L Blalock
- CNR-NationalResearch Council of Italy, Institute of Molecular Genetics, Bologna, Italy; SC Laboratory of Musculoskeletal Cell Biology, Rizzoli Orthopedic Institute, Bologna, Italy
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48
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De Felice FG, Ferreira ST. Inflammation, defective insulin signaling, and mitochondrial dysfunction as common molecular denominators connecting type 2 diabetes to Alzheimer disease. Diabetes 2014; 63:2262-72. [PMID: 24931033 DOI: 10.2337/db13-1954] [Citation(s) in RCA: 415] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A growing body of evidence supports an intriguing clinical/epidemiological connection between Alzheimer disease (AD) and type 2 diabetes (T2D). T2D patients have significantly increased risk of developing AD and vice versa. Recent studies have begun to reveal common pathogenic mechanisms shared by AD and metabolic disorders, notably obesity and T2D. In T2D and obesity, low-grade chronic inflammation is a key mechanism leading to peripheral insulin resistance, which progressively causes tissue deterioration and overall health decline. In the brain, proinflammatory signaling was recently found to mediate impaired neuronal insulin signaling, synapse deterioration, and memory loss. Here, we review evidence indicating that inflammation, insulin resistance, and mitochondrial dysfunction are common features in AD and T2D. We further propose the hypothesis that dementia and its underlying neuronal dysfunction are exacerbated or driven by peripheral inflammation. Identification of central and peripheral inflammation as potential mediators of brain dysfunction in AD may lead to the development of effective treatments for this devastating disease.
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Affiliation(s)
- Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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Affiliation(s)
- Licio A Velloso
- Laboratory of Cell Signaling, Obesity and Comorbidities Research Center, University of Campinas, Campinas, Brazil
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50
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Chen T, Takrouri K, Hee-Hwang S, Rana S, Yefidoff-Freedman R, Halperin J, Natarajan A, Morisseau C, Hammock B, Chorev M, Aktas BH. Explorations of substituted urea functionality for the discovery of new activators of the heme-regulated inhibitor kinase. J Med Chem 2013; 56:9457-70. [PMID: 24261904 DOI: 10.1021/jm400793v] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Heme-regulated inhibitor kinase (HRI), a eukaryotic translation initiation factor 2 alpha (eIF2α) kinase, plays critical roles in cell proliferation, differentiation, and adaptation to cytoplasmic stress. HRI is also a critical modifier of hemoglobin disorders such as β-thalassemia. We previously identified N,N'-diarylureas as potent activators of HRI suitable for studying the biology of this important kinase. To expand the repertoire of chemotypes that activate HRI, we screened a ∼1900 member N,N'-disubstituted urea library in the surrogate eIF2α phosphorylation assay, identifying N-aryl,N'-cyclohexylphenoxyurea as a promising scaffold. We validated hit compounds as a bona fide HRI activators in secondary assays and explored the contributions of substitutions on the N-aryl and N'-cyclohexylphenoxy groups to their activity by studying focused libraries of complementing analogues. We tested these N-aryl,N'-cyclohexylphenoxyureas in the surrogate eIF2α phosphorylation and cell proliferation assays, demonstrating significantly improved bioactivities and specificities. We consider these compounds to represent lead candidates for the development of potent and specific HRI activators.
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Affiliation(s)
- Ting Chen
- Hematology Laboratory for Translational Research, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School , 75 Francis Street, Boston, Massachusetts 02115, United States
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