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Lien CC, Yin WH, Yang DM, Chen LK, Chen CW, Liu SY, Kwok CF, Ho LT, Juan CC. Endothelin-1 induces lipolysis through activation of the GC/cGMP/Ca 2+/ERK/CaMKIII pathway in 3T3-L1 adipocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1867:159071. [PMID: 34748972 DOI: 10.1016/j.bbalip.2021.159071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 10/24/2021] [Accepted: 11/03/2021] [Indexed: 02/07/2023]
Abstract
Endothelin-1 (ET-1) is a potent vasoconstrictive peptide produced and secreted mainly by endothelial cells. Recent studies indicate that ET-1 can regulate lipid metabolism, which may increase the risk of insulin resistance. Our previous studies revealed that ET-1 induced lipolysis in adipocytes, but the underlying mechanisms were unclear. 3T3-L1 adipocytes were used to investigate the effect of ET-1 on lipolysis and the underlying mechanisms. Glycerol levels in the incubation medium and hormone-sensitive lipase (HSL) phosphorylation were used as indices for lipolysis. ET-1 significantly increased HSL phosphorylation and lipolysis, which were completely inhibited by ERK inhibitor (PD98059) and guanylyl cyclase (GC) inhibitor (LY83583). LY83583 reduced ET-1-induced ERK phosphorylation. A Ca2+-free medium and PLC inhibitor caused significant decreases in ET-1-induced lipolysis as well as ERK and HSL phosphorylation, and IP3 receptor activator (D-IP3) increased lipolysis. ET-1 increased cGMP production, which was not affected by depletion of extracellular Ca2+. On the other hand, LY83583 diminished the ET-1-induced Ca2+ influx. Transient receptor potential vanilloid-1 (TRPV-1) antagonist and shRNA partially inhibited ET-1-induced lipolysis. ET-1-induced lipolysis was completely suppressed by CaMKIII inhibitor (NH-125). These results indicate that ET-1 stimulates extracellular Ca2+ entry and activates the intracellular PLC/IP3/Ca2+ pathway through a cGMP-dependent pathway. The increased cytosolic Ca2+ that results from ET-1 treatment stimulates ERK and HSL phosphorylation, which subsequently induces lipolysis. ET-1 induces HSL phosphorylation and lipolysis via the GC/cGMP/Ca2+/ERK/CaMKIII signaling pathway in 3T3-L1 adipocytes.
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Affiliation(s)
- Chih-Chan Lien
- Institutes of Physiology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Life Science, College of Science, Chinese Culture University, Taipei, Taiwan
| | - Wei-Hsian Yin
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Division of Cardiology, Cheng-Hsin General Hospital, Taipei, Taiwan; Heart Center, Cheng-Hsin General Hospital, Taipei, Taiwan
| | - De-Ming Yang
- Institute of Biophotonics, College of Biomedical Science and Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Luen-Kui Chen
- Institutes of Physiology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chien-Wei Chen
- College of Human Development and Health, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Shui-Yu Liu
- Institutes of Physiology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ching-Fai Kwok
- Division of Metabolism, Cheng-Hsin General Hospital, Taipei, Taiwan; Division of Endocrinology and Metabolism, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Low-Tone Ho
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Endocrinology and Metabolism, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chi-Chang Juan
- Institutes of Physiology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.
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Prasanna G, Narayan S, Krishnamoorthy RR, Yorio T. Eyeing endothelins: a cellular perspective. Mol Cell Biochem 2004; 253:71-88. [PMID: 14619958 DOI: 10.1023/a:1026005418874] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Endothelin is an endogenous vasoactive peptide that is considered among the most potent vasoconstrictor substances known. In addition to its vascular effects, endothelins and their receptors have been shown to be present in the eye and to have a number of ocular actions that may be important for ocular homeostasis, but, in excess can be a potential contributor to ocular neuropathy in glaucoma. The current review focuses on the cellular and molecular aspects of endothelins and its receptors in the eye with an emphasis on its relationship to ocular function and its potential role in the etiology of glaucoma pathophysiology.
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Affiliation(s)
- Ganesh Prasanna
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
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Abstract
Endothelins are widely distributed in the body and perform several vascular and nonvascular functions. Experimental data indicate abnormalities of the endothelin system in several organs affected in chronic diabetic complications. In support of this notion, it has been shown that endothelin-receptor antagonists prevent structural and functional abnormalities in target organs of diabetic complications in animal models. Alterations of plasma endothelin levels have also been demonstrated in human diabetes. This review discusses the role of endothelins in the pathogenesis of chronic diabetic complications. The current experimental evidence suggests that endothelin-receptor antagonism may potentially be an adjuvant therapeutic tool in the treatment of chronic diabetic complications.
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Affiliation(s)
- Zia Ali Khan
- Department of Pathology, University of Western Ontario, London, ON N6A 5C1, Canada
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Ding KH, Isales CM, Zhong Q, Bollag RJ. Functional analysis of glucose-dependent insulinotropic polypeptide fusion proteins. Peptides 2001; 22:575-82. [PMID: 11311726 DOI: 10.1016/s0196-9781(01)00366-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To generate functional fluorescently tagged glucose-dependent insulinotropic polypeptide (GIP), a series of GIP expression constructs were devised. These included G1 (complete preprohormone), G2 (lacking the C-terminal extension), G3 (lacking both N- and C-terminal extensions), G4 (G2 fused to green fluorescent protein, GFP), and G5 (G3 fused to GFP). Expression of G5 in bacteria generated immunopositive GIP together with GFP fluorescence, while G4 generated only fluorescence without immunoreactivity. Transfection of NIH3T3 cells with cDNAs of G1, G3, G5, but not G2, G4, and EGFP, resulted in immunologically detectable GIP formation, although fluorescence could be detected in the latter two. GIP as well as GIP-GFP secreted by NIH3T3 cells significantly stimulated intracellular cAMP accumulation and Ca(2+) mobilization in SaOS2 cells. The GIP receptor antagonist GIP(7-30) abolished these responses. These results suggest that a GIP-GFP fusion protein seven times larger than the native peptide retains function and may be used as an in vivo probe to detect GIP receptor distribution and to explore GIP's biological roles.
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Affiliation(s)
- K H Ding
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA
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Ali N, Yousufzai SY, Abdel-Latif AA. Activation of particulate guanylate cyclase by adrenomedullin in cultured SV-40 transformed cat iris sphincter smooth muscle (SV-CISM-2) cells. Cell Signal 2000; 12:491-8. [PMID: 10989285 DOI: 10.1016/s0898-6568(00)00094-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We investigated the effects of adrenomedullin (ADM) on cGMP production in cultured SV-40 transformed cat iris sphincter smooth muscle (SV-CISM-2) cells. ADM increased cGMP accumulation in a time- and concentration- dependent manner. The peptide increased cGMP formation in the transformed cells by 405-fold as compared to 1. 6-fold in primary cultured CISM cells. The basal cGMP concentrations in both cell types were comparable. In addition, ADM increased cAMP accumulation in SV-CISM-2 cells and in primary cultured cells by 18. 9- and 5.8-fold, respectively. The ADM receptor antagonist, ADM(26-52), but not the atrial natriuretic peptide (ANP) receptor antagonist, anantin, inhibited ADM-induced cGMP formation. The phorbol ester, phorbol 12, 13-dibutyrate (PDBu), which inhibits particulate guanylate cyclases in smooth muscle, blocked ADM-stimulated cGMP accumulation. In contrast, inhibitors of the soluble guanylate cyclases, such as LY83583 and ODQ, and inhibitors of the nitric oxide cascade had little effect on ADM-stimulated cGMP production. The stimulatory effect of ADM on cGMP formation is due to activation of the guanylate cyclase system and not to a much reduced phosphodiesterase activity. ADM stimulated guanylate cyclase activity in membrane fractions isolated from SV-CISM-2 cells in a concentration-dependent manner with EC(50) value of 72 nM. Pertussis toxin, an activator of the G-protein, Gi, inhibited ADM-stimulated cGMP accumulation, whereas cholera toxin, a stimulator of the Gs G-protein and subsequently cAMP accumulation, had little effect. Pretreatment of the plasma membrane fraction with Gialpha antibody attenuated ADM-stimulated guanylate cyclase activity by 75%. We conclude that ADM increases intracellular cGMP levels in SV-CISM-2 cells through activation of the ADM receptor and subsequent stimulation of a Gi-mediated membrane-bound guanylate cyclase.
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Affiliation(s)
- N Ali
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, GA 30912-2100, USA
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