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Lucas RM, Luo L, Stow JL. ERK1/2 in immune signalling. Biochem Soc Trans 2022; 50:1341-1352. [PMID: 36281999 PMCID: PMC9704528 DOI: 10.1042/bst20220271] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 07/30/2023]
Abstract
Extracellular signal-related kinases 1 and 2 (ERK1/2) are the final components of the mitogen-activated protein kinase (MAPK) phosphorylation cascade, an integral module in a diverse array of signalling pathways for shaping cell behaviour and fate. More recently, studies have shown that ERK1/2 plays an essential role downstream of immune receptors to elicit inflammatory gene expression in response to infection and cell or tissue damage. Much of this work has studied ERK1/2 activation in Toll-like receptor (TLR) pathways, providing mechanistic insights into its recruitment, compartmentalisation and activation in cells of the innate immune system. In this review, we summarise the typical activation of ERK1/2 in growth factor receptor pathways before discussing its known roles in immune cell signalling with a focus downstream of TLRs. We examine emerging research uncovering evidence of dysfunctional ERK1/2 signalling in inflammatory diseases and discuss the potential therapeutic benefit of targeting ERK1/2 pathways in inflammation.
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Affiliation(s)
- Richard M. Lucas
- Institute for Molecular Bioscience (IMB) and Centre for Inflammation and Disease Research, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Lin Luo
- Institute for Molecular Bioscience (IMB) and Centre for Inflammation and Disease Research, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Jennifer L. Stow
- Institute for Molecular Bioscience (IMB) and Centre for Inflammation and Disease Research, The University of Queensland, St Lucia, QLD 4072, Australia
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2
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Mollinedo F, Gajate C. Novel therapeutic approaches for pancreatic cancer by combined targeting of RAF→MEK→ERK signaling and autophagy survival response. ANNALS OF TRANSLATIONAL MEDICINE 2019; 7:S153. [PMID: 31576360 PMCID: PMC6685885 DOI: 10.21037/atm.2019.06.40] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Faustino Mollinedo
- Department of Molecular Biomedicine, Laboratory of Cell Death and Cancer Therapy, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Consuelo Gajate
- Department of Molecular Biomedicine, Laboratory of Cell Death and Cancer Therapy, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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3
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Coover RA, Healy TE, Guo L, Chaney KE, Hennigan RF, Thomson CS, Aschbacher-Smith LE, Jankowski MP, Ratner N. Tonic ATP-mediated growth suppression in peripheral nerve glia requires arrestin-PP2 and is evaded in NF1. Acta Neuropathol Commun 2018; 6:127. [PMID: 30470263 PMCID: PMC6251093 DOI: 10.1186/s40478-018-0635-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/14/2018] [Indexed: 12/15/2022] Open
Abstract
Normal Schwann cells (SCs) are quiescent in adult nerves, when ATP is released from the nerve in an activity dependent manner. We find that suppressing nerve activity in adult nerves causes SC to enter the cell cycle. In vitro, ATP activates the SC G-protein coupled receptor (GPCR) P2Y2. Downstream of P2Y2, β-arrestin-mediated signaling results in PP2-mediated de-phosphorylation of AKT, and PP2 activity is required for SC growth suppression. NF1 deficient SC show reduced growth suppression by ATP, and are resistant to the effects of β-arrestin-mediated signaling, including PP2-mediated de-phosphorylation of AKT. In patients with the disorder Neurofibromatosis type 1, NF1 mutant SCs proliferate and form SC tumors called neurofibromas. Elevating ATP levels in vivo reduced neurofibroma cell proliferation. Thus, the low proliferation characteristic of differentiated adult peripheral nerve may require ongoing, nerve activity-dependent, ATP. Additionally, we identify a mechanism through which NF1 SCs may evade growth suppression in nerve tumors.
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Wandler A, Shannon K. Mechanistic and Preclinical Insights from Mouse Models of Hematologic Cancer Characterized by Hyperactive Ras. Cold Spring Harb Perspect Med 2018; 8:a031526. [PMID: 28778967 PMCID: PMC5880163 DOI: 10.1101/cshperspect.a031526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RAS genes are mutated in 5%-40% of a spectrum of myeloid and lymphoid cancers with NRAS affected 2-3 times more often than KRAS Genomic analysis indicates that RAS mutations generally occur as secondary events in leukemogenesis, but are integral to the disease phenotype. The tractable nature of the hematopoietic system has facilitated generating accurate mouse models of hematologic malignancies characterized by hyperactive Ras signaling. These strains provide robust platforms for addressing how oncogenic Ras expression perturbs proliferation, differentiation, and self-renewal programs in stem and progenitor cell populations, for testing potential therapies, and for investigating mechanisms of drug response and resistance. This review summarizes recent insights from key studies in mouse models of hematologic cancer that are broadly relevant for understanding Ras biology and for ongoing efforts to implement rational therapeutic strategies for cancers with oncogenic RAS mutations.
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Affiliation(s)
- Anica Wandler
- Department of Pediatrics, Helen Diller Family Cancer Research Building, University of California, San Francisco, San Francisco, California 94158-9001
| | - Kevin Shannon
- Department of Pediatrics, Helen Diller Family Cancer Research Building, University of California, San Francisco, San Francisco, California 94158-9001
- Comprehensive Cancer Center, Helen Diller Family Cancer Research Building, University of California, San Francisco, San Francisco, California 94158-9001
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5
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Survival of pancreatic cancer cells lacking KRAS function. Nat Commun 2017; 8:1090. [PMID: 29061961 PMCID: PMC5653666 DOI: 10.1038/s41467-017-00942-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 08/07/2017] [Indexed: 02/06/2023] Open
Abstract
Activating mutations in the proto-oncogene KRAS are a hallmark of pancreatic ductal adenocarcinoma (PDAC), an aggressive malignancy with few effective therapeutic options. Despite efforts to develop KRAS-targeted drugs, the absolute dependence of PDAC cells on KRAS remains incompletely understood. Here we model complete KRAS inhibition using CRISPR/Cas-mediated genome editing and demonstrate that KRAS is dispensable in a subset of human and mouse PDAC cells. Remarkably, nearly all KRAS deficient cells exhibit phosphoinositide 3-kinase (PI3K)-dependent mitogen-activated protein kinase (MAPK) signaling and induced sensitivity to PI3K inhibitors. Furthermore, comparison of gene expression profiles of PDAC cells retaining or lacking KRAS reveal a role of KRAS in the suppression of metastasis-related genes. Collectively, these data underscore the potential for PDAC resistance to even the very best KRAS inhibitors and provide insights into mechanisms of response and resistance to KRAS inhibition. Pancreatic cancer cells may develop resistance to KRAS inhibitors due to activation of compensatory pathways. In this study, the authors demonstrate that KRAS is dispensable in a subset of pancreatic cancer and that PI3K signalling may have an important role in mediating tumor growth following KRAS inhibition.
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Sachs Z, Been RA, DeCoursin KJ, Nguyen HT, Mohd Hassan NA, Noble-Orcutt KE, Eckfeldt CE, Pomeroy EJ, Diaz-Flores E, Geurts JL, Diers MD, Hasz DE, Morgan KJ, MacMillan ML, Shannon KM, Largaespada DA, Wiesner SM. Stat5 is critical for the development and maintenance of myeloproliferative neoplasm initiated by Nf1 deficiency. Haematologica 2016; 101:1190-1199. [PMID: 27418650 DOI: 10.3324/haematol.2015.136002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 06/15/2016] [Indexed: 11/09/2022] Open
Abstract
Juvenile myelomonocytic leukemia is a rare myeloproliferative neoplasm characterized by hyperactive RAS signaling. Neurofibromin1 (encoded by the NF1 gene) is a negative regulator of RAS activation. Patients with neurofibromatosis type 1 harbor loss-of-function mutations in NF1 and have a 200- to 500-fold increased risk of juvenile myelomonocytic leukemia. Leukemia cells from patients with juvenile myelomonocytic leukemia display hypersensitivity to certain cytokines, such as granulocyte-macrophage colony-stimulating factor. The granulocyte-macrophage colony-stimulating factor receptor utilizes pre-associated JAK2 to initiate signals after ligand binding. JAK2 subsequently activates STAT5, among other downstream effectors. Although STAT5 is gaining recognition as an important mediator of growth factor signaling in myeloid leukemias, the contribution of STAT5 to the development of hyperactive RAS-initiated myeloproliferative disease has not been well described. In this study, we investigated the consequence of STAT5 attenuation via genetic and pharmacological approaches in Nf1-deficient murine models of juvenile myelomonocytic leukemia. We found that homozygous Stat5 deficiency extended the lifespan of Nf1-deficient mice and eliminated the development of myeloproliferative neoplasm associated with Nf1 gene loss. Likewise, we found that JAK inhibition with ruxolitinib attenuated myeloproliferative neoplasm in Nf1-deficient mice. Finally, we found that primary cells from a patient with KRAS-mutant juvenile myelomonocytic leukemia displayed reduced colony formation in response to JAK2 inhibition. Our findings establish a central role for STAT5 activation in the pathogenesis of juvenile myelomonocytic leukemia and suggest that targeting this pathway may be of clinical utility in these patients.
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Affiliation(s)
- Zohar Sachs
- Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, USA Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Raha A Been
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA College of Veterinary Medicine and Department of Comparative and Molecular Biosciences, University of Minnesota, St. Paul, MN, USA
| | | | - Hanh T Nguyen
- Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | | | - Klara E Noble-Orcutt
- Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Craig E Eckfeldt
- Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Emily J Pomeroy
- Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Ernesto Diaz-Flores
- Department of Pediatrics, University of California, San Francisco, CA, USA Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Jennifer L Geurts
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Miechaleen D Diers
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Diane E Hasz
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Kelly J Morgan
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Margaret L MacMillan
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA Blood and Marrow Transplantation Program, University of Minnesota, Minneapolis, MN, USA
| | - Kevin M Shannon
- Department of Pediatrics, University of California, San Francisco, CA, USA Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - David A Largaespada
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA Blood and Marrow Transplantation Program, University of Minnesota, Minneapolis, MN, USA
| | - Stephen M Wiesner
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA Center for Allied Health Programs, University of Minnesota, Minneapolis, MN, USA
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Xiang RF, Stack D, Huston SM, Li SS, Ogbomo H, Kyei SK, Mody CH. Ras-related C3 Botulinum Toxin Substrate (Rac) and Src Family Kinases (SFK) Are Proximal and Essential for Phosphatidylinositol 3-Kinase (PI3K) Activation in Natural Killer (NK) Cell-mediated Direct Cytotoxicity against Cryptococcus neoformans. J Biol Chem 2016; 291:6912-22. [PMID: 26867574 PMCID: PMC4807276 DOI: 10.1074/jbc.m115.681544] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 01/13/2016] [Indexed: 11/06/2022] Open
Abstract
The activity of Rac in leukocytes is essential for immunity. However, its role in NK cell-mediated anti-microbial signaling remains unclear. In this study, we investigated the role of Rac in NK cell mediated anti-cryptococcal killing. We found thatCryptococcus neoformansindependently activates both Rac and SFK pathways in NK cells, and unlike in tumor killing,Cryptococcusinitiated a novel Rac → PI3K → Erk cytotoxicity cascade. Remarkably, Rac was not required for conjugate formation, despite its essential role in NK cytotoxicity againstC. neoformans Taken together, our data show that, unlike observations with tumor cells, NK cells use a novel Rac cytotoxicity pathway in conjunction with SFK, to killC. neoformans.
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Affiliation(s)
- Richard F Xiang
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Danuta Stack
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Shaunna M Huston
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Shu Shun Li
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Henry Ogbomo
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Stephen K Kyei
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Christopher H Mody
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada Internal Medicine and
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Targeting the PI3K/Akt pathway in murine MDS/MPN driven by hyperactive Ras. Leukemia 2016; 30:1335-43. [PMID: 26965285 PMCID: PMC4889473 DOI: 10.1038/leu.2016.14] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/13/2015] [Accepted: 01/04/2016] [Indexed: 12/25/2022]
Abstract
Chronic and juvenile myelomonocytic leukemias (CMML and JMML) are myelodysplastic/myeloproliferative neoplasia (MDS/MPN) overlap syndromes that respond poorly to conventional treatments. Aberrant Ras activation due to NRAS, KRAS, PTPN11, CBL, and NF1 mutations is common in CMML and JMML. However, no mechanism-based treatments currently exist for cancers with any of these mutations. An alternative therapeutic strategy involves targeting Ras-regulated effector pathways that are aberrantly activated in CMML and JMML, which include the Raf/MEK/ERK and phosphoinositide-3´-OH kinase (PI3K)/Akt cascades. Mx1-Cre, KrasD12 and Mx1-Cre, Nf1flox/− mice accurately model many aspects of CMML and JMML. Treating Mx1-Cre, KrasD12 mice with GDC-0941 (also referred to as pictilisib), an orally bioavailable inhibitor of class I PI3K isoforms, reduced leukocytosis, anemia, and splenomegaly while extending survival. However, GDC-0941 treatment attenuated activation of both PI3K/Akt and Raf/MEK/ERK pathways in primary hematopoietic cells, suggesting it could be acting through suppression of Raf/MEK/ERK signals. To interrogate the importance of the PI3K/Akt pathway specifically, we treated mice with the allosteric Akt inhibitor MK-2206. This compound had no effect on Raf/MEK/ERK signaling, yet it also induced robust hematologic responses in Kras and Nf1 mice with MPN. These data support investigating PI3K/Akt pathway inhibitors as a therapeutic strategy in JMML and CMML patients.
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Nutter FH, Haylor JL, Khwaja A. Inhibiting ERK Activation with CI-1040 Leads to Compensatory Upregulation of Alternate MAPKs and Plasminogen Activator Inhibitor-1 following Subtotal Nephrectomy with No Impact on Kidney Fibrosis. PLoS One 2015; 10:e0137321. [PMID: 26415098 PMCID: PMC4586140 DOI: 10.1371/journal.pone.0137321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 08/15/2015] [Indexed: 11/27/2022] Open
Abstract
Extracellular-signal regulated kinase (ERK) activation by MEK plays a key role in many of the cellular processes that underlie progressive kidney fibrosis including cell proliferation, apoptosis and transforming growth factor β1-mediated epithelial to mesenchymal transition. We therefore assessed the therapeutic impact of ERK1/2 inhibition using a MEK inhibitor in the rat 5/6 subtotal nephrectomy (SNx) model of kidney fibrosis. There was a twentyfold upregulation in phospho-ERK1/2 expression in the kidney after SNx in Male Wistar rats. Rats undergoing SNx became hypertensive, proteinuric and developed progressive kidney failure with reduced creatinine clearance. Treatment with the MEK inhibitor, CI-1040 abolished phospho- ERK1/2 expression in kidney tissue and prevented phospho-ERK1/2 expression in peripheral lymphocytes during the entire course of therapy. CI-1040 had no impact on creatinine clearance, proteinuria, glomerular and tubular fibrosis, and α-smooth muscle actin expression. However, inhibition of ERK1/2 activation led to significant compensatory upregulation of the MAP kinases, p38 and JNK in kidney tissue. CI-1040 also increased the expression of plasminogen activator inhibitor-1 (PAI-1), a key inhibitor of plasmin-dependent matrix metalloproteinases. Thus inhibition of ERK1/2 activation has no therapeutic effect on kidney fibrosis in SNx possibly due to increased compensatory activation of the p38 and JNK signalling pathways with subsequent upregulation of PAI-1.
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Affiliation(s)
- Faith Hannah Nutter
- Academic Unit of Nephrology, Department of Infection and Immunity, Medical School, University of Sheffield, Sheffield, England
- * E-mail:
| | - John L. Haylor
- Academic Unit of Nephrology, Department of Infection and Immunity, Medical School, University of Sheffield, Sheffield, England
| | - Arif Khwaja
- Sheffield Kidney Institute, Northern General Hospital, Sheffield, England
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Compromised MAPK signaling in human diseases: an update. Arch Toxicol 2015; 89:867-82. [PMID: 25690731 DOI: 10.1007/s00204-015-1472-2] [Citation(s) in RCA: 711] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 02/09/2015] [Indexed: 02/08/2023]
Abstract
The mitogen-activated protein kinases (MAPKs) in mammals include c-Jun NH2-terminal kinase (JNK), p38 MAPK, and extracellular signal-regulated kinase (ERK). These enzymes are serine-threonine protein kinases that regulate various cellular activities including proliferation, differentiation, apoptosis or survival, inflammation, and innate immunity. The compromised MAPK signaling pathways contribute to the pathology of diverse human diseases including cancer and neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. The JNK and p38 MAPK signaling pathways are activated by various types of cellular stress such as oxidative, genotoxic, and osmotic stress as well as by proinflammatory cytokines such as tumor necrosis factor-α and interleukin 1β. The Ras-Raf-MEK-ERK signaling pathway plays a key role in cancer development through the stimulation of cell proliferation and metastasis. The p38 MAPK pathway contributes to neuroinflammation mediated by glial cells including microglia and astrocytes, and it has also been associated with anticancer drug resistance in colon and liver cancer. We here summarize recent research on the roles of MAPK signaling pathways in human diseases, with a focus on cancer and neurodegenerative conditions.
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Zhang Y, Ying J, Jiang D, Chang Z, Li H, Zhang G, Gong S, Jiang X, Tao J. Urotensin-II receptor stimulation of cardiac L-type Ca2+ channels requires the βγ subunits of Gi/o-protein and phosphatidylinositol 3-kinase-dependent protein kinase C β1 isoform. J Biol Chem 2015; 290:8644-55. [PMID: 25678708 DOI: 10.1074/jbc.m114.615021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recent studies have demonstrated that urotensin-II (U-II) plays important roles in cardiovascular actions including cardiac positive inotropic effects and increasing cardiac output. However, the mechanisms underlying these effects of U-II in cardiomyocytes still remain unknown. We show by electrophysiological studies that U-II dose-dependently potentiates L-type Ca(2+) currents (ICa,L) in adult rat ventricular myocytes. This effect was U-II receptor (U-IIR)-dependent and was associated with a depolarizing shift in the voltage dependence of inactivation. Intracellular application of guanosine-5'-O-(2-thiodiphosphate) and pertussis toxin pretreatment both abolished the stimulatory effects of U-II. Dialysis of cells with the QEHA peptide, but not scrambled peptide SKEE, blocked the U-II-induced response. The phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin as well as the class I PI3K antagonist CH132799 blocked the U-II-induced ICa,L response. Protein kinase C antagonists calphostin C and chelerythrine chloride as well as dialysis of cells with 1,2bis(2aminophenoxy)ethaneN,N,N',N'-tetraacetic acid abolished the U-II-induced responses, whereas PKCα inhibition or PKA blockade had no effect. Exposure of ventricular myocytes to U-II markedly increased membrane PKCβ1 expression, whereas inhibition of PKCβ1 pharmacologically or by shRNA targeting abolished the U-II-induced ICa,L response. Functionally, we observed a significant increase in the amplitude of sarcomere shortening induced by U-II; blockade of U-IIR as well as PKCβ inhibition abolished this effect, whereas Bay K8644 mimicked the U-II response. Taken together, our results indicate that U-II potentiates ICa,L through the βγ subunits of Gi/o-protein and downstream activation of the class I PI3K-dependent PKCβ1 isoform. This occurred via the activation of U-IIR and contributes to the positive inotropic effect on cardiomyocytes.
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Affiliation(s)
- Yuan Zhang
- From the Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou 215123, China, Department of Geriatrics and Institute of Neuroscience, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China
| | - Jiaoqian Ying
- From the Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou 215123, China, Department of Emergency Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Dongsheng Jiang
- From the Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou 215123, China, Department of Dermatology and Allergic Diseases, University of Ulm, Ulm 89081, Germany, and
| | - Zhigang Chang
- From the Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou 215123, China
| | - Hua Li
- From the Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou 215123, China, National Shanghai Center for New Drug Safety Evaluation and Research, Shanghai 201203, China
| | - Guoqiang Zhang
- Department of Emergency Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Shan Gong
- From the Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou 215123, China
| | - Xinghong Jiang
- From the Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou 215123, China
| | - Jin Tao
- From the Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou 215123, China,
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