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Iannucci LF, D'Erchia AM, Picardi E, Bettio D, Conca F, Surdo NC, Di Benedetto G, Musso D, Arrigoni C, Lolicato M, Vismara M, Grisan F, Salviati L, Milanesi L, Pesole G, Lefkimmiatis K. Cyclic AMP induces reversible EPAC1 condensates that regulate histone transcription. Nat Commun 2023; 14:5521. [PMID: 37684224 PMCID: PMC10491619 DOI: 10.1038/s41467-023-41088-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
The second messenger cyclic AMP regulates many nuclear processes including transcription, pre-mRNA splicing and mitosis. While most functions are attributed to protein kinase A, accumulating evidence suggests that not all nuclear cyclic AMP-dependent effects are mediated by this kinase, implying that other effectors may be involved. Here we explore the nuclear roles of Exchange Protein Activated by cyclic AMP 1. We find that it enters the nucleus where forms reversible biomolecular condensates in response to cyclic AMP. This phenomenon depends on intrinsically disordered regions present at its amino-terminus and is independent of protein kinase A. Finally, we demonstrate that nuclear Exchange Protein Activated by cyclic AMP 1 condensates assemble at genomic loci on chromosome 6 in the proximity of Histone Locus Bodies and promote the transcription of a histone gene cluster. Collectively, our data reveal an unexpected mechanism through which cyclic AMP contributes to nuclear spatial compartmentalization and promotes the transcription of specific genes.
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Affiliation(s)
- Liliana Felicia Iannucci
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Veneto Institute of Molecular Medicine, 35129, Padova, Italy
| | - Anna Maria D'Erchia
- Department of Biosciences, Biotechnologies and Environment, University of Bari "Aldo Moro", Bari, Italy
| | - Ernesto Picardi
- Department of Biosciences, Biotechnologies and Environment, University of Bari "Aldo Moro", Bari, Italy
| | - Daniela Bettio
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Filippo Conca
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Veneto Institute of Molecular Medicine, 35129, Padova, Italy
| | - Nicoletta Concetta Surdo
- Veneto Institute of Molecular Medicine, 35129, Padova, Italy
- Institute of Neuroscience (IN-CNR), National Research Council of Italy, Padova, Italy
| | - Giulietta Di Benedetto
- Veneto Institute of Molecular Medicine, 35129, Padova, Italy
- Institute of Neuroscience (IN-CNR), National Research Council of Italy, Padova, Italy
| | - Deborah Musso
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | | | - Marco Lolicato
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Mauro Vismara
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Veneto Institute of Molecular Medicine, 35129, Padova, Italy
| | | | - Leonardo Salviati
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Luciano Milanesi
- Institute of Biomedical Technologies, National Research Council of Italy, Milan, Italy
| | - Graziano Pesole
- Department of Biosciences, Biotechnologies and Environment, University of Bari "Aldo Moro", Bari, Italy
| | - Konstantinos Lefkimmiatis
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.
- Veneto Institute of Molecular Medicine, 35129, Padova, Italy.
- Institute of Neuroscience (IN-CNR), National Research Council of Italy, Padova, Italy.
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2
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Yang W, Xia F, Mei F, Shi S, Robichaux WG, Lin W, Zhang W, Liu H, Cheng X. Upregulation of Epac1 Promotes Pericyte Loss by Inducing Mitochondrial Fission, Reactive Oxygen Species Production, and Apoptosis. Invest Ophthalmol Vis Sci 2023; 64:34. [PMID: 37651112 PMCID: PMC10476449 DOI: 10.1167/iovs.64.11.34] [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] [Received: 03/30/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023] Open
Abstract
Purpose The pathogenic mechanisms behind the development of ischemic retinopathy are complex and poorly understood. This study investigates the involvement of exchange protein directly activated by cAMP (Epac)1 signaling in pericyte injury during ischemic retinopathy, including diabetic retinopathy, a disease that threatens vision. Methods Mouse models of retinal ischemia-reperfusion injury and type 1 diabetes induced by streptozotocin were used to investigate the pathogenesis of these diseases. The roles of Epac1 signaling in the pathogenesis of ischemic retinopathy were determined by an Epac1 knockout mouse model. The cellular and molecular mechanisms of Epac1-mediated pericyte dysfunction in response to high glucose were investigated by specific modulation of Epac1 activity in primary human retinal pericytes using Epac1-specific RNA interference and a pharmacological inhibitor. Results Ischemic injury or diabetes-induced retinal capillary degeneration were associated with an increased expression of Epac1 in the mouse retinal vasculature, including both endothelial cells and pericytes. Genetic deletion of Epac1 protected ischemic injury-induced pericyte loss and capillary degeneration in the mouse retina. Furthermore, high glucose-induced Epac1 expression in retinal pericytes was accompanied by increased Drp1 phosphorylation, mitochondrial fission, reactive oxygen species production, and caspase 3 activation. Inhibition of Epac1 via RNA interference or pharmacological approaches blocked high glucose-mediated mitochondrial dysfunction and caspase 3 activation. Conclusions Our study reveals an important role of Epac1 signaling in mitochondrial dynamics, reactive oxygen species production, and apoptosis in retinal pericytes and identifies Epac1 as a therapeutic target for treating ischemic retinopathy.
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Affiliation(s)
- Wenli Yang
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
| | - Fan Xia
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - Fang Mei
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
| | - Shuizhen Shi
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - William G. Robichaux
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
| | - Wei Lin
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
| | - Wenbo Zhang
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
- Department of Neurobiology, University of Texas Medical Branch, Galveston, Texas, United States
| | - Hua Liu
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas, United States
- Texas Therapeutics Institute, University of Texas Health Science Center, Houston, Texas, United States
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3
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Pan Y, Liu J, Ren J, Luo Y, Sun X. Epac: A Promising Therapeutic Target for Vascular Diseases: A Review. Front Pharmacol 2022; 13:929152. [PMID: 35910387 PMCID: PMC9330031 DOI: 10.3389/fphar.2022.929152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Vascular diseases affect the circulatory system and comprise most human diseases. They cause severe symptoms and affect the quality of life of patients. Recently, since their identification, exchange proteins directly activated by cAMP (Epac) have attracted increasing scientific interest, because of their role in cyclic adenosine monophosphate (cAMP) signaling, a well-known signal transduction pathway. The role of Epac in cardiovascular disease and cancer is extensively studied, whereas their role in kidney disease has not been comprehensively explored yet. In this study, we aimed to review recent studies on the regulatory effects of Epac on various vascular diseases, such as cardiovascular disease, cerebrovascular disease, and cancer. Accumulating evidence has shown that both Epac1 and Epac2 play important roles in vascular diseases under both physiological and pathological conditions. Additionally, there has been an increasing focus on Epac pharmacological modulators. Therefore, we speculated that Epac could serve as a novel therapeutic target for the treatment of vascular diseases.
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Affiliation(s)
- Yunfeng Pan
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Efficacy Evaluation of Chinese Medicine Against Glycolipid Metabolic Disorders, State Administration of Traditional Chinese Medicine, Beijing, China
| | - Jia Liu
- Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Jiahui Ren
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Efficacy Evaluation of Chinese Medicine Against Glycolipid Metabolic Disorders, State Administration of Traditional Chinese Medicine, Beijing, China
| | - Yun Luo
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Efficacy Evaluation of Chinese Medicine Against Glycolipid Metabolic Disorders, State Administration of Traditional Chinese Medicine, Beijing, China
| | - Xiaobo Sun
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Efficacy Evaluation of Chinese Medicine Against Glycolipid Metabolic Disorders, State Administration of Traditional Chinese Medicine, Beijing, China
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4
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Kawaguchi T, Hasegawa K, Yasuda I, Muraoka H, Umino H, Tokuyama H, Hashiguchi A, Wakino S, Itoh H. Diabetic condition induces hypertrophy and vacuolization in glomerular parietal epithelial cells. Sci Rep 2021; 11:1515. [PMID: 33452384 PMCID: PMC7810998 DOI: 10.1038/s41598-021-81027-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 12/09/2020] [Indexed: 01/29/2023] Open
Abstract
Diabetic nephropathy (DN) is accompanied by characteristic changes in the glomerulus, but little is known about the effect of diabetes on parietal epithelial cells (PECs). In this study, a descriptive analysis of PECs was undertaken in diabetic db/db mice and in diabetic patients. PEC hypertrophy was significantly more prominent in diabetic mice than in nondiabetic mice, and this was evident even at the early stage. Additionally, the number of vacuoles in PECs was markedly increased in diabetic mice, suggesting the presence of cellular injury in PECs in DN. Although rare, binuclear cells were observed in mice with early diabetes. In cultured PECs, a high glucose condition, compared with normal glucose condition, induced cellular hypertrophy and apoptosis. Flow cytometry showed that some PECs in the G0 phase reentered the cell cycle but got arrested in the S phase. Finally, in human diabetic subjects, hypertrophy and vacuolization were observed in the PECs. Our data showed that PECs undergo substantial changes in DN and may participate in rearrangement for differentiation into podocytes.
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Affiliation(s)
- Takahisa Kawaguchi
- grid.26091.3c0000 0004 1936 9959Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan
| | - Kazuhiro Hasegawa
- grid.26091.3c0000 0004 1936 9959Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan
| | - Itaru Yasuda
- grid.26091.3c0000 0004 1936 9959Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan
| | - Hirokazu Muraoka
- grid.26091.3c0000 0004 1936 9959Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan
| | - Hiroyuki Umino
- grid.26091.3c0000 0004 1936 9959Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan
| | - Hirobumi Tokuyama
- grid.26091.3c0000 0004 1936 9959Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan
| | - Akinori Hashiguchi
- grid.26091.3c0000 0004 1936 9959Department of Pathology, School of Medicine, Keio University, Tokyo, 160-8582 Japan
| | - Shu Wakino
- grid.26091.3c0000 0004 1936 9959Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan
| | - Hiroshi Itoh
- grid.26091.3c0000 0004 1936 9959Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan
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5
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Formoso K, Lezoualc'h F, Mialet-Perez J. Role of EPAC1 Signalosomes in Cell Fate: Friends or Foes? Cells 2020; 9:E1954. [PMID: 32854274 PMCID: PMC7563956 DOI: 10.3390/cells9091954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/21/2020] [Accepted: 08/22/2020] [Indexed: 02/06/2023] Open
Abstract
The compartmentation of signaling processes is accomplished by the assembly of protein complexes called signalosomes. These signaling platforms colocalize enzymes, substrates, and anchoring proteins into specific subcellular compartments. Exchange protein directly activated by cAMP 1 (EPAC1) is an effector of the second messenger, 3',5'-cyclic adenosine monophosphate (cAMP) that is associated with multiple roles in several pathologies including cardiac diseases. Both EPAC1 intracellular localization and molecular partners are key players in the regulation of cell fate, which may have important therapeutic potential. In this review, we summarize the recent findings on EPAC1 structure, regulation, and pharmacology. We describe the importance of EPAC1 subcellular distribution in its biological action, paying special attention to its nuclear localization and mechanism of action leading to cardiomyocyte hypertrophy. In addition, we discuss the role of mitochondrial EPAC1 in the regulation of cell death. Depending on the cell type and stress condition, we present evidence that supports either a protective or detrimental role of EPAC1 activation.
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Affiliation(s)
- Karina Formoso
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
| | - Frank Lezoualc'h
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
| | - Jeanne Mialet-Perez
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
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A Glimpse of the Mechanisms Related to Renal Fibrosis in Diabetic Nephropathy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1165:49-79. [PMID: 31399961 DOI: 10.1007/978-981-13-8871-2_4] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diabetic nephropathy (DN) is a common kidney disease in people with diabetes, which is also a serious microvascular complication of diabetes and the main cause of end-stage renal disease (ESRD) in developed and developing countries. Renal fibrosis is a finally pathological change in DN. Nevertheless, the relevant mechanism of cause to renal fibrosis in DN is still complex. In this review, we summarized that the role of cell growth factors, epithelial-mesenchymal transition (EMT) in the renal fibrosis of DN, we also highlighted the miRNA and inflammatory cells, such as macrophage, T lymphocyte, and mastocyte modulate the progression of DN. In addition, there are certain other mechanisms that may yet be conclusively defined. Recent studies demonstrated that some of the new signaling pathways or molecules, such as Notch, Wnt, mTOR, Epac-Rap-1 pathway, may play a pivotal role in the modulation of ECM accumulation and renal fibrosis in DN. This review aims to elucidate the mechanism of renal fibrosis in DN and has provided new insights into possible therapeutic interventions to inhibit renal fibrosis and delay the development of DN.
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Song S, Qiu D, Luo F, Wei J, Wu M, Wu H, Du C, Du Y, Ren Y, Chen N, Duan H, Shi Y. Knockdown of NLRP3 alleviates high glucose or TGFB1-induced EMT in human renal tubular cells. J Mol Endocrinol 2018; 61:101-113. [PMID: 30307163 DOI: 10.1530/jme-18-0069] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Tubular injury is one of the crucial determinants of progressive renal failure in diabetic nephropathy (DN), while epithelial-to-mesenchymal transition (EMT) of tubular cells contributes to the accumulation of matrix protein in the diabetic kidney. Activation of the nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome leads to the maturation of interleukin (IL)-1B and is involved in the pathogenic mechanisms of diabetes. In this study, we explored the role of NLRP3 inflammasome on high glucose (HG) or transforming growth factor-B1 (TGFB1)-induced EMT in HK-2 cells. We evaluated EMT through the expression of α-smooth muscle actin (α-SMA) and E-cadherin as well as the induction of a myofibroblastic phenotype. Reactive oxygen species (ROS) was observed using the confocal microscopy. HG was shown to induce EMT at 48 h, which was blocked by NLRP3 silencing or antioxidant N-acetyl-L-cysteine (NAC). We found that NLRP3 interference could inhibit HG-induced ROS. Knockdown of NLRP3 could prevent HG-induced EMT by inhibiting the phosphorylation of SMAD3, P38 MAPK and ERK1/2. In addition, P38 MAPK and ERK1/2 might be involved in HG-induced NLRP3 inflammasome activation. Besides, TGFB1 induced the activation of NLRP3 inflammasome and the generation of ROS, which were blocked by NLRP3 interference or NAC. Tubular cells exposed to TGFB1 also underwent EMT, and this could be inhibited by NLRP3 shRNA or NAC. These results indicated that knockdown of NLRP3 antagonized HG-induced EMT by inhibiting ROS production, phosphorylation of SMAD3, P38MAPK and ERK1/2, highlighting NLRP3 as a potential therapy target for diabetic nephropathy.
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Affiliation(s)
- Shan Song
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Duojun Qiu
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Fengwei Luo
- Renal Division, Department of Medicine, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jinying Wei
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
- Hebei Key Laboratory of Kidney Diseases, Shijiazhuang, China
| | - Ming Wu
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Haijiang Wu
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
- Hebei Key Laboratory of Kidney Diseases, Shijiazhuang, China
| | - Chunyang Du
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
- Hebei Key Laboratory of Kidney Diseases, Shijiazhuang, China
| | - Yunxia Du
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
- Hebei Key Laboratory of Kidney Diseases, Shijiazhuang, China
| | - Yunzhuo Ren
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
- Hebei Key Laboratory of Kidney Diseases, Shijiazhuang, China
| | - Nan Chen
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Huijun Duan
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
- Hebei Key Laboratory of Kidney Diseases, Shijiazhuang, China
| | - Yonghong Shi
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
- Hebei Key Laboratory of Kidney Diseases, Shijiazhuang, China
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Robichaux WG, Cheng X. Intracellular cAMP Sensor EPAC: Physiology, Pathophysiology, and Therapeutics Development. Physiol Rev 2018; 98:919-1053. [PMID: 29537337 PMCID: PMC6050347 DOI: 10.1152/physrev.00025.2017] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 12/13/2022] Open
Abstract
This review focuses on one family of the known cAMP receptors, the exchange proteins directly activated by cAMP (EPACs), also known as the cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs). Although EPAC proteins are fairly new additions to the growing list of cAMP effectors, and relatively "young" in the cAMP discovery timeline, the significance of an EPAC presence in different cell systems is extraordinary. The study of EPACs has considerably expanded the diversity and adaptive nature of cAMP signaling associated with numerous physiological and pathophysiological responses. This review comprehensively covers EPAC protein functions at the molecular, cellular, physiological, and pathophysiological levels; and in turn, the applications of employing EPAC-based biosensors as detection tools for dissecting cAMP signaling and the implications for targeting EPAC proteins for therapeutic development are also discussed.
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Affiliation(s)
- William G Robichaux
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
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Cai HD, Su SL, Qian DW, Guo S, Tao WW, Cong XD, Tang R, Duan JA. Renal protective effect and action mechanism of Huangkui capsule and its main five flavonoids. JOURNAL OF ETHNOPHARMACOLOGY 2017; 206:152-159. [PMID: 28408246 DOI: 10.1016/j.jep.2017.02.046] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 02/12/2017] [Accepted: 02/20/2017] [Indexed: 06/07/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The flower of Abelmoschus manihot (Linn.) Medicus (A. manihot), as a traditional Chinese Herbal medicine, was used widely in China with efficacy of inducing diuresis for treating strangurtia, and subdhing swelling and detoxicating. It has been reported that Huangkui capsule, prepared by the extract of the flower of A. manihot, can reduce the content of urinary protein, serum creatinine and serum urea nitrogen in nephropathy rats and processes renoprotective activity, while the action mechanism need to illuminate deeply. AIMS OF THE STUDY In this study, we investigated the protection effect of Huangkui capsule on tubulointerstitial fibrosis in chronic renal failure (CRF) rats and its mechanism against high glucose-induced epithelial to mesenchymal transition (EMT) in renal tubular epithelial cells (HK-2) of its bioactive components. MATERIALS AND METHODS The animals were divided into normal group, CRF model group and Huangkui capsule-treated group. Hematoxylin eosin (HE) staining and Masson staining were applied to observe pathological changes in renal tissue of different groups. Biochemical indicators including serum urea nitrogen (BUN), urine protein (UP) and serum creatinine (Scr) were measured according to the manufacturer's instructions of kits. HK-2 cell damaged model was established to access the protection effect and action mechanism of five main flavonoids from Huangkui capsule. The experimental cells were divided into eight groups: control group, model group, positive drug group and five main flavonoids treated groups. The dichlorodihydrofluorescein diacetate (DCFH-DA) assay was used to determine the reactive oxygen species (ROS) in different groups. Western blot was applied to analyze the expression of pathogenesis-related proteins in different groups. RESULTS The results stated that Huangkui capsule significantly inhibited the elevation of Scr, BUN, UP, the expression of α-smooth muscle actin (α-SMA), phosphorylation-extracellular signal-regulated kinase (p-ERK1/2), NADPH Oxidase 1, NADPH Oxidase 2 and NADPH Oxidase 4 in adenine-induced CRF rats. The main bioactive components of quercetin (QT), hyperoside (HY), isoquercitrin (IQT), gossypetin-8-O-β-D-glucuronide (GG) and quercetin-3'-O-glucoside (QG) at the dosage of 100µM, like NADPH oxidase inhibitor diphenyleneiodonium, exhibited a significant effect on inhibiting the expression of α-SMA, p-ERK1/2, NADPH Oxidase 1, NADPH Oxidase 2 and NADPH Oxidase 4 in high glucose-induced HK-2 cells, especially GG. CONCLUSIONS These results demonstrated that Huangkui capsule and the flavonoids components prevent tubulointerstitial fibrosis in CRF rat involvement in the action mechanism of inhibiting NADPH oxidase/ROS/ERK pathway.
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Affiliation(s)
- Hong-Die Cai
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, and National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Shu-Lan Su
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, and National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Da-Wei Qian
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, and National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Sheng Guo
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, and National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Wei-Wei Tao
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, and National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China; Center for Translational Systems Biology and Neuroscience, Laboratory of Integrative Biomedicine of Brain Diseases, School of Basic Biomedical Science, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Xu Dong Cong
- SZYY Group Pharmaceutical Limited, Jiangyan 225500, China
| | - Renmao Tang
- SZYY Group Pharmaceutical Limited, Jiangyan 225500, China.
| | - Jin-Ao Duan
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, and National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
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Renoprotective Effects of Aldose Reductase Inhibitor Epalrestat against High Glucose-Induced Cellular Injury. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5903105. [PMID: 28386557 PMCID: PMC5366186 DOI: 10.1155/2017/5903105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 02/21/2017] [Indexed: 12/30/2022]
Abstract
Diabetic nephropathy (DN) is the leading cause of end stage renal disease worldwide. Increased glucose flux into the aldose reductase (AR) pathway during diabetes was reported to exert deleterious effects on the kidney. The objective of this study was to investigate the renoprotective effects of AR inhibition in high glucose milieu in vitro. Rat renal tubular (NRK-52E) cells were exposed to high glucose (30 mM) or normal glucose (5 mM) media for 24 to 48 hours with or without the AR inhibitor epalrestat (1 μM) and assessed for changes in Akt and ERK1/2 signaling, AR expression (using western blotting), and alterations in mitochondrial membrane potential (using JC-1 staining), cell viability (using MTT assay), and cell cycle. Exposure of NRK-52E cells to high glucose media caused acute activation of Akt and ERK pathways and depolarization of mitochondrial membrane at 24 hours. Prolonged high glucose exposure (for 48 hours) induced AR expression and G1 cell cycle arrest and decreased cell viability (84% compared to control) in NRK-52E cells. Coincubation of cells with epalrestat prevented the signaling changes and renal cell injury induced by high glucose. Thus, AR inhibition represents a potential therapeutic strategy to prevent DN.
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Li F, Li L, Hao J, Liu S, Duan H. Src Homology 2 Domain-Containing Inositol 5'-Phosphatase Ameliorates High Glucose-Induced Extracellular Matrix Deposition via the Phosphatidylinositol 3-Kinase/Protein Kinase B Pathway in Renal Tubular Epithelial Cells. J Cell Biochem 2017; 118:2271-2284. [PMID: 28075049 DOI: 10.1002/jcb.25881] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 01/10/2017] [Indexed: 02/05/2023]
Abstract
A typical hallmark of diabetic kidney disease (DKD) is an excessive deposition of extracellular matrix (ECM) in the glomerulus and renal tubulointerstitium, leading to glomerulosclerosis and tubular interstitial fibrosis. Src homology 2 domain-containing inositol 5'-phosphatase (SHIP) is a negative regulator of the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling. Here, we investigated the effect of SHIP on ECM deposition in diabetic mice and high glucose-stimulated human renal tubular epithelial cells (HK2 cells). The decreased SHIP and increased phospho-Akt (Ser 473, Thr 308) were found in the renal tubular cells of diabetic mice, which were accompanied by overexpression of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA), and secreted collagen type 3 (Col 3) and a low expression of E-cadherin compared to that in normal mice. In vitro research revealed that high glucose-attenuated SHIP expression accompanied the activation of the PI3K/Akt signaling and ECM production. Knocking down SHIP in HK2 cells caused an increase in the levels of phospho-Akt (Ser 473), phospho-Akt (Thr 308), TGF-β1, α-SMA, and secreted Col 3 and a decrease in E-cadherin. Again, either the M90-SHIP plasmid or the PI3K/Akt pathway inhibitor LY294002 could significantly prevent the high glucose-induced increase in TGF-β1, α-SMA, and secreted Col 3 and decreased E-cadherin. Furthermore, we confirmed that inhibition of the TGF-β1 pathway with SB431542 blocked the effect of SHIP knockdown on ECM production in HK2 cells. In summary, our study suggests that decreased SHIP mediates high glucose-induced TGF-β1 upregulation and ECM deposition through activation of the PI3K/Akt pathway in renal tubular cells. J. Cell. Biochem. 118: 2271-2284, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Fan Li
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Lisha Li
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Jun Hao
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Shuxia Liu
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Huijun Duan
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
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12
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Baameur F, Singhmar P, Zhou Y, Hancock JF, Cheng X, Heijnen CJ, Kavelaars A. Epac1 interacts with importin β1 and controls neurite outgrowth independently of cAMP and Rap1. Sci Rep 2016; 6:36370. [PMID: 27808165 PMCID: PMC5093460 DOI: 10.1038/srep36370] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 10/14/2016] [Indexed: 01/23/2023] Open
Abstract
Exchange protein directly activated by cAMP-1 (Epac1) is a cAMP sensor that regulates multiple cellular functions including cellular migration, proliferation and differentiation. Classically, Epac1 is thought to exert its effects through binding of cAMP leading to a conformational change in Epac1 and its accumulation at the plasma membrane (PM) where it activates Rap1. In search for regulators of Epac1 activity, we show here that importin β1 (impβ1) is an Epac1 binding partner that prevents PM accumulation of Epac1. We demonstrate that in the absence of impβ1, endogenous as well as overexpressed Epac1 accumulate at the PM. Moreover, agonist-induced PM translocation of Epac1 leads to dissociation of Epac1 from impβ1. Localization of Epac1 at the PM in the absence of impβ1, requires residue R82 in its DEP domain. Notably, the PM accumulation of Epac1 in the absence of impβ1 does not require binding of cAMP to Epac1 and does not result in Rap1 activation. Functionally, PM accumulation of Epac1, an Epac1 mutant deficient in cAMP binding, or an Epac1 mutant tethered to the PM, is sufficient to inhibit neurite outgrowth. In conclusion, we uncover a cAMP-independent function of Epac1 at the PM and demonstrate that impβ1 controls subcellular localization of Epac1.
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Affiliation(s)
- Faiza Baameur
- Laboratory of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Pooja Singhmar
- Laboratory of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yong Zhou
- Department of Integrative Biology and Pharmacology and Texas Therapeutics Institute, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - John F Hancock
- Department of Integrative Biology and Pharmacology and Texas Therapeutics Institute, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology and Texas Therapeutics Institute, The University of Texas Health Science Center, Houston, TX 77030, USA
| | - Cobi J Heijnen
- Laboratory of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Annemieke Kavelaars
- Laboratory of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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13
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Xu X, Zhu X, Ma M, Han Y, Hu C, Yuan S, Yang Y, Xiao L, Liu F, Kanwar YS, Sun L. p66Shc: A novel biomarker of tubular oxidative injury in patients with diabetic nephropathy. Sci Rep 2016; 6:29302. [PMID: 27377870 PMCID: PMC4932503 DOI: 10.1038/srep29302] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/17/2016] [Indexed: 12/15/2022] Open
Abstract
Increased p66Shc expression has been associated with diabetic nephropathy (DN). However, whether p66Shc can serve as a potential biomarker for tubular oxidative injury in DN is unknown. We measured the expression of p66Shc in peripheral blood monocytes (PBMs) and renal biopsy tissues from DN patients and then analysed the relationship between p66Shc expression and the clinical characteristics of patients with DN. Patients were divided into 4 groups (class IIa, class IIb, class III and the control group). qPCR, Western blotting and immunohistochemistry were performed. The results showed that both p66Shc and p-p66Shc expression significantly increased in PBMs and kidney tissues of DN patients. Moreover, Spearman’s correlation and multiple regression analyses were carried out. A positive relationship between the p66Shc expression and oxidative stress was found. p66Shc and oxidative stress were significant predictors of the degree of tubular damage. In addition, p66Shc expression was positively correlated with the concentrations of β-NAG, UACR and 8-OHdG, low-density lipoprotein and blood glucose levels, and duration of diabetes in patients with DN from class IIa to class III. These data indicated that increased expression of p66Shc may serve as a therapeutic target and a novel biomarker of DN.
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Affiliation(s)
- Xiaoxuan Xu
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xuejing Zhu
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mingming Ma
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yachun Han
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chun Hu
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shuguang Yuan
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yuan Yang
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Li Xiao
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Fuyou Liu
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yashpal S Kanwar
- Departments of Pathology &Medicine, Northwestern University, Chicago, USA
| | - Lin Sun
- Department of Nephrology, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
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14
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Gao M, Ma Y, Bast RC, Li Y, Wan L, Liu Y, Sun Y, Fang Z, Zhang L, Wang X, Wei Z. Epac1 knockdown inhibits the proliferation of ovarian cancer cells by inactivating AKT/Cyclin D1/CDK4 pathway in vitro and in vivo. Med Oncol 2016; 33:73. [PMID: 27277757 DOI: 10.1007/s12032-016-0786-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 05/27/2016] [Indexed: 12/14/2022]
Abstract
Ovarian cancer is the leading cause of death among gynecological malignancies, and high grade serous ovarian carcinoma is the most common and most aggressive subtype. Recently, it was demonstrated that cAMP mediates protein kinase A-independent effects through Epac (exchange protein directly activated by cAMP) proteins. Epac proteins, including Epac1 and Epac2, are implicated in several diverse cellular responses, such as insulin secretion, exocytosis, cellular calcium handling and formation of cell-cell junctions. Several reports document that Epac1 could play vital roles in promoting proliferation, invasion and migration of some cancer cells. However, the expression levels and roles of Epac1 in ovarian cancer have not been investigated. In the present study, we detected the expression levels of Epac1 mRNA and protein in three kinds of ovarian cancer cells SKOV3, OVCAR3 and CAOV3. Furthermore, the effect of Epac1 knockdown on the proliferation and apoptosis of SKOV3 and OVCAR3 cells was evaluated in vitro and in vivo. The results showed that there was higher expression of Epac1 mRNA and protein in SKOV3 and OVCAR3 cells. Epac1 knockdown inhibited the proliferation of SKOV3 and OVCAR3 cells in vitro and in vivo. Decreased proliferation may be due to downregulation of Epac1-induced G1 phase arrest by inactivating the AKT/Cyclin D1/CDK4 pathway, but not to alterations in the MAPK pathway or to apoptosis. Taken together, our data provide new insight into the essential role of Epac1 in regulating growth of ovarian cancer cells and suggest that Epac1 might represent an attractive therapeutic target for treatment of ovarian cancer.
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Affiliation(s)
- Meng Gao
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Yanyan Ma
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Robert C Bast
- Department of Experimental Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yue Li
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Lu Wan
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Yanping Liu
- Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated to Shandong University, 105# Jiefang Road, Jinan, 250013, Shandong, People's Republic of China.,Department of Gynecology and Obstetrics, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Yingshuo Sun
- Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated to Shandong University, 105# Jiefang Road, Jinan, 250013, Shandong, People's Republic of China.,Department of Gynecology and Obstetrics, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Zhenghui Fang
- Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated to Shandong University, 105# Jiefang Road, Jinan, 250013, Shandong, People's Republic of China
| | - Lining Zhang
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Xiaoyan Wang
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China.
| | - Zengtao Wei
- Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated to Shandong University, 105# Jiefang Road, Jinan, 250013, Shandong, People's Republic of China. .,Department of Gynecology and Obstetrics, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China.
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15
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Sugihara M, Sadamori H, Nishibori M, Sato Y, Tazawa H, Shinoura S, Umeda Y, Yoshida R, Nobuoka D, Utsumi M, Ohno K, Nagasaka T, Yoshino T, Takahashi HK, Yagi T, Fujiwara T. Anti–high mobility group box 1 monoclonal antibody improves ischemia/reperfusion injury and mode of liver regeneration after partial hepatectomy. Am J Surg 2016; 211:179-88. [DOI: 10.1016/j.amjsurg.2015.06.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 06/10/2015] [Accepted: 06/25/2015] [Indexed: 01/27/2023]
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16
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Li X, Li C, Li X, Cui P, Li Q, Guo Q, Han H, Liu S, Sun G. Involvement of Histone Lysine Methylation in p21 Gene Expression in Rat Kidney In Vivo and Rat Mesangial Cells In Vitro under Diabetic Conditions. J Diabetes Res 2016; 2016:3853242. [PMID: 27652271 PMCID: PMC5019898 DOI: 10.1155/2016/3853242] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 07/27/2016] [Indexed: 01/21/2023] Open
Abstract
Diabetic nephropathy (DN), a common complication associated with type 1 and type 2 diabetes mellitus (DM), characterized by glomerular mesangial expansion, inflammation, accumulation of extracellular matrix (ECM) protein, and hypertrophy, is the major cause of end-stage renal disease (ESRD). Increasing evidence suggested that p21-dependent glomerular and mesangial cell (MC) hypertrophy play key roles in the pathogenesis of DN. Recently, posttranscriptional modifications (PTMs) have uncovered novel molecular mechanisms involved in DN. However, precise regulatory mechanism of histone lysine methylation (HKme) mediating p21 related hypertrophy associated with DN is not clear. We evaluated the roles of HKme and histone methyltransferase (HMT) SET7/9 in p21 gene expression in glomeruli of diabetic rats and in high glucose- (HG-) treated rat mesangial cells (RMCs). p21 gene expression was upregulated in diabetic rats glomeruli; chromatin immunoprecipitation (ChIP) assays showed decreased histone H3-lysine9-dimethylation (H3K9me2) accompanied with enhanced histone H3-lysine4-methylation (H3K4me1/3) and SET7/9 occupancies at the p21 promoter. HG-treated RMCs exhibited increased p21 mRNA, H3K4me level, SET7/9 recruitment, and inverse H3K9me, which were reversed by TGF-β1 antibody. These data uncovered key roles of H3Kme and SET7/9 responsible for p21 gene expression in vivo and in vitro under diabetic conditions and confirmed preventive effect of TGF-β1 antibody on DN.
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Affiliation(s)
- Xiangjun Li
- Department of Experimental Pharmacology and Toxicology, School of Pharmaceutical Science, Jilin University, Changchun, Jilin 130021, China
| | - Chaoyuan Li
- Department of Nephrology, 2nd Hospital of Jilin University, Changchun, Jilin 130041, China
| | - Xiaoxia Li
- Department of Nephrology, 2nd Hospital of Jilin University, Changchun, Jilin 130041, China
| | - Peihe Cui
- Department of Nephrology, 2nd Hospital of Jilin University, Changchun, Jilin 130041, China
| | - Qifeng Li
- Department of Nephrology, 2nd Hospital of Jilin University, Changchun, Jilin 130041, China
| | - Qiaoyan Guo
- Department of Nephrology, 2nd Hospital of Jilin University, Changchun, Jilin 130041, China
| | - Hongbo Han
- Department of Endocrinology, 208th Hospital of Chinese PLA, Changchun, Jilin 130062, China
| | - Shujun Liu
- Department of Nephrology, 2nd Hospital of Jilin University, Changchun, Jilin 130041, China
| | - Guangdong Sun
- Department of Nephrology, 2nd Hospital of Jilin University, Changchun, Jilin 130041, China
- *Guangdong Sun:
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17
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Banerjee U, Cheng X. Exchange protein directly activated by cAMP encoded by the mammalian rapgef3 gene: Structure, function and therapeutics. Gene 2015; 570:157-67. [PMID: 26119090 PMCID: PMC4556420 DOI: 10.1016/j.gene.2015.06.063] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 06/23/2015] [Indexed: 01/08/2023]
Abstract
Mammalian exchange protein directly activated by cAMP isoform 1 (EPAC1), encoded by the RAPGEF3 gene, is one of the two-membered family of cAMP sensors that mediate the intracellular functions of cAMP by acting as guanine nucleotide exchange factors for the Ras-like Rap small GTPases. Extensive studies have revealed that EPAC1-mediated cAMP signaling is highly coordinated spatiotemporally through the formation of dynamic signalosomes by interacting with a diverse array of cellular partners. Recent functional analyses of genetically engineered mouse models further suggest that EPAC1 functions as an important stress response switch and is involved in pathophysiological conditions of cardiac stresses, chronic pain, cancer and infectious diseases. These findings, coupled with the development of EPAC specific small molecule modulators, validate EPAC1 as a promising target for therapeutic interventions. Human gene RAPGEF3 encodes for EPAC1 protein. Along with PKA, CNG & HCN, EPAC is an important cAMP sensor. Selective modulators of EPAC1 have been developed for use as pharmacological probes. Formation of EPAC1 signalosomes allows spatiotemporal control of cAMP signaling. EPAC1 is implicated in major pathophysiological conditions and is an attractive therapeutic target.
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Affiliation(s)
- Upasana Banerjee
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Health Science Center, Houston, TX 77030, United States
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Health Science Center, Houston, TX 77030, United States.
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18
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He T, Guan X, Wang S, Xiao T, Yang K, Xu X, Wang J, Zhao J. Resveratrol prevents high glucose-induced epithelial-mesenchymal transition in renal tubular epithelial cells by inhibiting NADPH oxidase/ROS/ERK pathway. Mol Cell Endocrinol 2015; 402:13-20. [PMID: 25540919 DOI: 10.1016/j.mce.2014.12.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 12/11/2014] [Accepted: 12/11/2014] [Indexed: 11/28/2022]
Abstract
Resveratrol (RSV) is reported to have renoprotective activity against diabetic nephropathy, while the mechanisms underlying its function have not been fully elucidated. In this study, we investigate the effect and related mechanism of RSV against high glucose-induced epithelial to mesenchymal transition (EMT) in human tubular epithelial cells (HK-2). A typical EMT is induced by high glucose in HK-2 cells, accompanied by increased levels of reactive oxygen species (ROS). RSV exhibits a strong ability to inhibit high glucose-induced EMT by decreasing intracellular ROS levels via down-regulation of NADPH oxidase subunits NOX1 and NOX4. The activation of extracellular signal-regulated kinase (ERK1/2) is found to be involved in high glucose-induced EMT in HK-2 cells. RSV, like NADPH oxidase inhibitor diphenyleneiodonium, can block ERK1/2 activation induced by high glucose. Our results demonstrate that RSV is a potent agent against high glucose-induced EMT in renal tubular cells via inhibition of NADPH oxidase/ROS/ERK1/2 pathway.
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Affiliation(s)
- Ting He
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Xu Guan
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Song Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury of PLA, Third Military Medical University, Chongqing 400038, China
| | - Tangli Xiao
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Ke Yang
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Xinli Xu
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Junping Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury of PLA, Third Military Medical University, Chongqing 400038, China
| | - Jinghong Zhao
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
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19
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Role of soluble adenylyl cyclase in cell death and growth. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2646-55. [PMID: 25010002 DOI: 10.1016/j.bbadis.2014.06.034] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 12/13/2022]
Abstract
cAMP signaling is an evolutionarily conserved intracellular communication system controlling numerous cellular functions. Until recently, transmembrane adenylyl cyclase (tmAC) was considered the major source for cAMP in the cell, and the role of cAMP signaling was therefore attributed exclusively to the activity of this family of enzymes. However, increasing evidence demonstrates the role of an alternative, intracellular source of cAMP produced by type 10 soluble adenylyl cyclase (sAC). In contrast to tmAC, sAC produces cAMP in various intracellular microdomains close to specific cAMP targets, e.g., in nucleus and mitochondria. Ongoing research demonstrates involvement of sAC in diverse physiological and pathological processes. The present review is focused on the role of cAMP signaling, particularly that of sAC, in cell death and growth. Although the contributions of sAC to the regulation of these cellular functions have only recently been discovered, current data suggest that sAC plays key roles in mitochondrial bioenergetics and the mitochondrial apoptosis pathway, as well as cell proliferation and development. Furthermore, recent reports suggest the importance of sAC in several pathologies associated with apoptosis as well as in oncogenesis. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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20
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Xiao L, Zhu X, Yang S, Liu F, Zhou Z, Zhan M, Xie P, Zhang D, Li J, Song P, Kanwar YS, Sun L. Rap1 ameliorates renal tubular injury in diabetic nephropathy. Diabetes 2014; 63:1366-80. [PMID: 24353183 PMCID: PMC3964498 DOI: 10.2337/db13-1412] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rap1b ameliorates high glucose (HG)-induced mitochondrial dysfunction in tubular cells. However, its role and precise mechanism in diabetic nephropathy (DN) in vivo remain unclear. We hypothesize that Rap1 plays a protective role in tubular damage of DN by modulating primarily the mitochondria-derived oxidative stress. The role and precise mechanisms of Rap1b on mitochondrial dysfunction and of tubular cells in DN were examined in rats with streptozotocin (STZ)-induced diabetes that have Rap1b gene transfer using an ultrasound microbubble-mediated technique as well as in renal proximal epithelial tubular cell line (HK-2) exposed to HG ambiance. The results showed that Rap1b expression decreased significantly in tubules of renal biopsies from patients with DN. Overexpression of a constitutively active Rap1b G12V notably ameliorated renal tubular mitochondrial dysfunction, oxidative stress, and apoptosis in the kidneys of STZ-induced rats, which was accompanied with increased expression of transcription factor C/EBP-β and PGC-1α. Furthermore, Rap1b G12V also decreased phosphorylation of Drp-1, a key mitochondrial fission protein, while boosting the expression of genes related to mitochondrial biogenesis and antioxidants in HK-2 cells induced by HG. These effects were imitated by transfection with C/EBP-β or PGC-1α short interfering RNA. In addition, Rap1b could modulate C/EBP-β binding to the endogenous PGC-1α promoter and the interaction between PGC-1α and catalase or mitochondrial superoxide dismutase, indicating that Rap1b ameliorates tubular injury and slows the progression of DN by modulation of mitochondrial dysfunction via C/EBP-β-PGC-1α signaling.
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Affiliation(s)
- Li Xiao
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xuejing Zhu
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shikun Yang
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Fuyou Liu
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhiguang Zhou
- Diabetes Center, Institute of Metabolism and Endocrinology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ming Zhan
- Department of Pathology, Northwestern University, Chicago, IL
- Department of Medicine, Northwestern University, Chicago, IL
| | - Ping Xie
- Department of Pathology, Northwestern University, Chicago, IL
- Department of Medicine, Northwestern University, Chicago, IL
| | - Dongshan Zhang
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jun Li
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Panai Song
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yashpal S. Kanwar
- Department of Pathology, Northwestern University, Chicago, IL
- Department of Medicine, Northwestern University, Chicago, IL
| | - Lin Sun
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Corresponding author: Lin Sun,
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Xie P, Joladarashi D, Dudeja P, Sun L, Kanwar YS. Modulation of angiotensin II-induced inflammatory cytokines by the Epac1-Rap1A-NHE3 pathway: implications in renal tubular pathobiology. Am J Physiol Renal Physiol 2014; 306:F1260-74. [PMID: 24553435 DOI: 10.1152/ajprenal.00069.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Besides the glomerulus, the tubulointerstitium is often concomitantly affected in certain diseases, e.g., diabetic nephropathy, and activation of the renin-angiotensin system, to a certain extent, worsens its outcome because of perturbations in hemodynamics and possibly tubuloglomerular feedback. Certain studies suggest that pathobiology of the tubulointerstitium is influenced by small GTPases, e.g., Rap1. We investigated the effect of ANG II on inflammatory cytokines, while at the same time focusing on upstream effector of Rap1, i.e., Epac1, and some of the downstream tubular transport molecules, i.e., Na/H exchanger 3 (NHE3). ANG II treatment of LLC-PK1 cells decreased Rap1a GTPase activity in a time- and dose-dependent manner. ANG II treatment led to an increased membrane translocation of NHE3, which was reduced with Epac1 and PKA activators. ANG II-induced NHE3 translocation was notably reduced with the transfection of Rap1a dominant positive mutants, i.e., Rap1a-G12V or Rap1a-T35A. Transfection of cells with dominant negative Rap1a mutants, i.e., Rap1a-S17A, or Epac1 mutant, i.e., EPAC-ΔcAMP, normalized ANG II-induced translocation of NHE3. In addition, ANG II treatment led to an increased expression of inflammatory cytokines, i.e., IL-1β, IL-6, IL-8, and TNF-α, which was reduced with Rap1a-G12V or Rap1a-T35A transfection, while it reverted to previous comparable levels following transfection of Rap1a-S17A or EPAC-ΔcAMP. ANG II-induced expression of cytokines was reduced with the treatment with NHE3 inhibitor S3226 or with Epac1 and PKA activators. These data suggest that this novel Epac1-Rap1a-NHE3 pathway conceivably modulates ANG II-induced expression of inflammatory cytokines, and this information may yield the impetus for developing strategies to reduce tubulointertstitial inflammation in various renal diseases.
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Affiliation(s)
- Ping Xie
- Departments of Pathology and Medicine, Northwestern University, Chicago, Illinois; and
| | | | - Pradeep Dudeja
- Department of Medicine, University of Illinois, Chicago, Illinois
| | - Lin Sun
- Departments of Pathology and Medicine, Northwestern University, Chicago, Illinois; and
| | - Yashpal S Kanwar
- Departments of Pathology and Medicine, Northwestern University, Chicago, Illinois; and
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22
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Briffa JF, Grinfeld E, McAinch AJ, Poronnik P, Hryciw DH. Short term exposure to elevated levels of leptin reduces proximal tubule cell metabolic activity. Mol Cell Endocrinol 2014; 382:38-45. [PMID: 24036423 DOI: 10.1016/j.mce.2013.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 08/08/2013] [Accepted: 09/03/2013] [Indexed: 11/29/2022]
Abstract
Leptin plays a pathophysiological role in the kidney, however, its acute effects on the proximal tubule cells (PTCs) are unknown. In opossum kidney (OK) cells in vitro, Western blot analysis identified that exposure to leptin increases the phosphorylation of the mitogen-activated protein kinase (MAPK) p44/42 and the mammalian target of rapamycin (mTOR). Importantly leptin (0.05, 0.10, 0.25 and 0.50 μg/ml) significantly reduced the metabolic activity of PTCs, and significantly decreased protein content per cell. Investigation of the role of p44/42 and mTOR on metabolic activity and protein content per cell, demonstrated that in the presence of MAPK inhibitor U0126 and mTOR inhibitor Ku-63794, that the mTOR pathway is responsible for the reduction in PTC metabolic activity in response to leptin. However, p44/42 and mTOR play no role the reduced protein content per cell in OKs exposed to leptin. Therefore, leptin modulates metabolic activity in PTCs via an mTOR regulated pathway.
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Affiliation(s)
- Jessica F Briffa
- Biomedical and Lifestyle Diseases (BioLED) Unit, College of Health and Biomedicine, Victoria University, St Albans, VIC 3021, Australia; Department of Physiology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Esther Grinfeld
- Biomedical and Lifestyle Diseases (BioLED) Unit, College of Health and Biomedicine, Victoria University, St Albans, VIC 3021, Australia
| | - Andrew J McAinch
- Biomedical and Lifestyle Diseases (BioLED) Unit, College of Health and Biomedicine, Victoria University, St Albans, VIC 3021, Australia
| | - Philip Poronnik
- School of Medical Sciences, The Bosch Institute, The University of Sydney, NSW 2006, Australia
| | - Deanne H Hryciw
- Biomedical and Lifestyle Diseases (BioLED) Unit, College of Health and Biomedicine, Victoria University, St Albans, VIC 3021, Australia; Department of Physiology, The University of Melbourne, Parkville, VIC 3010, Australia.
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23
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Wei J, Shi Y, Hou Y, Ren Y, Du C, Zhang L, Li Y, Duan H. Knockdown of thioredoxin-interacting protein ameliorates high glucose-induced epithelial to mesenchymal transition in renal tubular epithelial cells. Cell Signal 2013; 25:2788-96. [PMID: 24041652 DOI: 10.1016/j.cellsig.2013.09.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Accepted: 09/06/2013] [Indexed: 12/15/2022]
Abstract
Epithelial to mesenchymal transition (EMT) of tubular cells contributes to the renal accumulation of matrix protein that is associated with diabetic nephropathy. Both high glucose and transforming growth factor-β (TGF-β) are able to induce EMT in cell culture. In this study, we examined the role of the thioredoxin-interacting protein (TXNIP) on EMT induced by high glucose or TGF-β1 in HK-2 cells. EMT was assessed by the expression of α-smooth muscle actin (α-SMA) and E-cadherin and the induction of a myofibroblastic phenotype. High glucose (30mM) was shown to induce EMT at 72h. This was blocked by knockdown of TXNIP or antioxidant NAC. Meanwhile, we also found that knockdown of TXNIP or antioxidant NAC inhibited high glucose-induced generation of reactive oxygen species (ROS), phosphorylation of p38 MAPK and ERK1/2 and expression of TGF-β1. HK-2 cells that were exposed to TGF-β1 (4ng/ml) also underwent EMT. The expression of TXNIP gene and protein was increased in HK-2 cells treated with TGF-β1. Transfection with TXNIP shRNA was able to attenuate TGF-β1 induced-EMT. These results suggested that knockdown of TXNIP antagonized high glucose-induced EMT by inhibiting ROS production, activation of p38 MAPK and ERK1/2, and expression of TGF-β1, highlighting TXNIP as a potential therapy target for diabetic nephropathy.
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Affiliation(s)
- Jinying Wei
- Department of Pathology, Hebei Medical University, Shijiazhuang, China; Key Laboratory of Kidney Diseases of Hebei Province, Shijiazhuang, China
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24
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Kim DI, Park SH. Sequential signaling cascade of IL-6 and PGC-1α is involved in high glucose-induced podocyte loss and growth arrest. Biochem Biophys Res Commun 2013; 435:702-7. [PMID: 23692924 DOI: 10.1016/j.bbrc.2013.05.046] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 05/10/2013] [Indexed: 11/29/2022]
Abstract
Podocyte loss, which is mediated by podocyte apoptosis, is implicated in the onset of diabetic nephropathy. In this study, we investigated the involvement of interleukin (IL)-6 in high glucose-induced apoptosis of rat podocytes. We also examined the pathophysiological role of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) in this system. High glucose treatment induced not only podocyte apoptosis but also podocyte growth arrest. High glucose treatment also increased IL-6 secretion and activated IL-6 signaling. The high glucose-induced podocyte apoptosis was blocked by IL-6 neutralizing antibody. IL-6 treatment or overexpression induced podocyte apoptosis and growth arrest, and IL-6 siRNA transfection blocked high glucose-induced podocyte apoptosis and growth arrest. Furthermore, high glucose or IL-6 treatment increased PGC-1α expression, and PGC-1α overexpression also induced podocyte apoptosis and growth arrest. PGC-1α siRNA transfection blocked high glucose-induced podocyte apoptosis and growth arrest. Collectively, these findings showed that high glucose promoted apoptosis and cell growth arrest in podocytes via IL-6 signaling. In addition, PGC-1α is involved in podocyte apoptosis and cell growth arrest. Therefore, blocking IL-6 and its downstream mediators such as IL6Rα, gp130 and PGC-1α may attenuate the progression of diabetic nephropathy.
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Affiliation(s)
- Dong Il Kim
- College of Veterinary Medicine, Chonnam National University, Gwangju 500 757, Republic of Korea
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25
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Yang SK, Xiao L, Li J, Liu F, Sun L, Kanwar YS. Role of guanine-nucleotide exchange factor Epac in renal physiology and pathophysiology. Am J Physiol Renal Physiol 2013; 304:F831-9. [PMID: 23364803 PMCID: PMC3625846 DOI: 10.1152/ajprenal.00711.2012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 01/28/2013] [Indexed: 12/13/2022] Open
Abstract
Exchange proteins directly activated by cAMP [Epac(s)] were discovered more than a decade ago as new sensors for the second messenger cAMP. The Epac family members, including Epac1 and Epac2, are guanine nucleotide exchange factors for the Ras-like small GTPases Rap1 and Rap2, and they function independently of protein kinase A. Given the importance of cAMP in kidney homeostasis, several molecular and cellular studies using specific Epac agonists have analyzed the role and regulation of Epac proteins in renal physiology and pathophysiology. The specificity of the functions of Epac proteins may depend upon their expression and localization in the kidney as well as their abundance in the microcellular environment. This review discusses recent literature data concerning the involvement of Epac in renal tubular transport physiology and renal glomerular cells where various signaling pathways are known to be operative. In addition, the potential role of Epac in kidney disorders, such as diabetic kidney disease and ischemic kidney injury, is discussed.
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Affiliation(s)
- Shi-kun Yang
- Department of Nephrology, The Second Xiangya Hospital, Kidney Institute of Nephrology, Central South University, Changsha, Hunan Province, China
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Zhang Z, Li BY, Li XL, Cheng M, Yu F, Lu WD, Cai Q, Wang JF, Zhou RH, Gao HQ, Shen L. Proteomic analysis of kidney and protective effects of grape seed procyanidin B2 in db/db mice indicate MFG-E8 as a key molecule in the development of diabetic nephropathy. Biochim Biophys Acta Mol Basis Dis 2013; 1832:805-16. [PMID: 23474305 DOI: 10.1016/j.bbadis.2013.02.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Revised: 02/04/2013] [Accepted: 02/27/2013] [Indexed: 12/14/2022]
Abstract
Diabetic nephropathy, as a severe microvascular complication of diabetic mellitus, has become the leading cause of end-stage renal diseases. However, no effective therapeutic strategy has been developed to prevent renal damage progression to end stage renal disease. Hence, the present study evaluated the protective effects of grape seed procyanidin B2 (GSPB2) and explored its molecular targets underlying diabetic nephropathy by a comprehensive quantitative proteomic analysis in db/db mice. Here, we found that oral administration of GSPB2 significantly attenuated the renal dysfunction and pathological changes in db/db mice. Proteome analysis by isobaric tags for relative and absolute quantification (iTRAQ) identified 53 down-regulated and 60 up-regulated proteins after treatment with GSPB2 in db/db mice. Western blot analysis confirmed that milk fat globule EGF-8 (MFG-E8) was significantly up-regulated in diabetic kidney. MFG-E8 silencing by transfection of MFG-E8 shRNA improved renal histological lesions by inhibiting phosphorylation of extracellular signal-regulated kinase1/2 (ERK1⁄2), Akt and glycogen synthase kinase-3beta (GSK-3β) in kidneys of db/db mice. In contrast, over-expression of MFG-E8 by injection of recombinant MFG-E8 resulted in the opposite effects. GSPB2 treatment significantly decreased protein levels of MFG-E8, phospho-ERK1/2, phospho-Akt, and phospho-GSK-3β in the kidneys of db/db mice. These findings yield insights into the pathogenesis of diabetic nephropathy, revealing MFG-E8 as a new therapeutic target and indicating GSPB2 as a prospective therapy by down-regulation of MFG-E8, along with ERK1/2, Akt and GSK-3β signaling pathway.
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Affiliation(s)
- Zhen Zhang
- Department of Geriatrics, Qi-Lu Hospital of Shandong University, Key Laboratory of Cardiovascular Proteomics of Shandong Province, People's Republic of China
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27
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Schmidt M, Dekker FJ, Maarsingh H. Exchange protein directly activated by cAMP (epac): a multidomain cAMP mediator in the regulation of diverse biological functions. Pharmacol Rev 2013; 65:670-709. [PMID: 23447132 DOI: 10.1124/pr.110.003707] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Since the discovery nearly 60 years ago, cAMP is envisioned as one of the most universal and versatile second messengers. The tremendous feature of cAMP to tightly control highly diverse physiologic processes, including calcium homeostasis, metabolism, secretion, muscle contraction, cell fate, and gene transcription, is reflected by the award of five Nobel prizes. The discovery of Epac (exchange protein directly activated by cAMP) has ignited a new surge of cAMP-related research and has depicted novel cAMP properties independent of protein kinase A and cyclic nucleotide-gated channels. The multidomain architecture of Epac determines its activity state and allows cell-type specific protein-protein and protein-lipid interactions that control fine-tuning of pivotal biologic responses through the "old" second messenger cAMP. Compartmentalization of cAMP in space and time, maintained by A-kinase anchoring proteins, phosphodiesterases, and β-arrestins, contributes to the Epac signalosome of small GTPases, phospholipases, mitogen- and lipid-activated kinases, and transcription factors. These novel cAMP sensors seem to implement certain unexpected signaling properties of cAMP and thereby to permit delicate adaptations of biologic responses. Agonists and antagonists selective for Epac are developed and will support further studies on the biologic net outcome of the activation of Epac. This will increase our current knowledge on the pathophysiology of devastating diseases, such as diabetes, cognitive impairment, renal and heart failure, (pulmonary) hypertension, asthma, and chronic obstructive pulmonary disease. Further insights into the cAMP dynamics executed by the Epac signalosome will help to optimize the pharmacological treatment of these diseases.
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Affiliation(s)
- Martina Schmidt
- Department of Molecular Pharmacology, Groningen Research Institute for Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands.
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