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Dakroub A, Dbouk A, Asfour A, Nasser SA, El-Yazbi AF, Sahebkar A, Eid AA, Iratni R, Eid AH. C-peptide in diabetes: A player in a dual hormone disorder? J Cell Physiol 2024; 239:e31212. [PMID: 38308646 DOI: 10.1002/jcp.31212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 01/16/2024] [Accepted: 01/22/2024] [Indexed: 02/05/2024]
Abstract
C-peptide, a byproduct of insulin synthesis believed to be biologically inert, is emerging as a multifunctional molecule. C-peptide serves an anti-inflammatory and anti-atherogenic role in type 1 diabetes mellitus (T1DM) and early T2DM. C-peptide protects endothelial cells by activating AMP-activated protein kinase α, thus suppressing the activity of NAD(P)H oxidase activity and reducing reactive oxygen species (ROS) generation. It also prevents apoptosis by regulating hyperglycemia-induced p53 upregulation and mitochondrial adaptor p66shc overactivation, as well as reducing caspase-3 activity and promoting expression of B-cell lymphoma-2. Additionally, C-peptide suppresses platelet-derived growth factor (PDGF)-beta receptor and p44/p42 mitogen-activated protein (MAP) kinase phosphorylation to inhibit vascular smooth muscle cells (VSMC) proliferation. It also diminishes leukocyte adhesion by virtue of its capacity to abolish nuclear factor kappa B (NF-kB) signaling, a major pro-inflammatory cascade. Consequently, it is envisaged that supplementation of C-peptide in T1DM might ameliorate or even prevent end-organ damage. In marked contrast, C-peptide increases monocyte recruitment and migration through phosphoinositide 3-kinase (PI-3 kinase)-mediated pathways, induces lipid accumulation via peroxisome proliferator-activated receptor γ upregulation, and stimulates VSMC proliferation and CD4+ lymphocyte migration through Src-kinase and PI-3K dependent pathways. Thus, it promotes atherosclerosis and microvascular damage in late T2DM. Indeed, C-peptide is now contemplated as a potential biomarker for insulin resistance in T2DM and linked to increased coronary artery disease risk. This shift in the understanding of the pathophysiology of diabetes from being a single hormone deficiency to a dual hormone disorder warrants a careful consideration of the role of C-peptide as a unique molecule with promising diagnostic, prognostic, and therapeutic applications.
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Affiliation(s)
- Ali Dakroub
- St. Francis Hospital and Heart Center, Roslyn, New York, USA
| | - Ali Dbouk
- Department of Medicine, Saint-Joseph University Medical School, Hotel-Dieu de France Hospital, Beirut, Lebanon
| | - Aref Asfour
- Leeds Teaching Hospitals NHS Trust, West Yorkshire, United Kingdom
| | | | - Ahmed F El-Yazbi
- Faculty of Pharmacy, Alamein International University (AIU), Alamein City, Egypt
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Assaad A Eid
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Rabah Iratni
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, UAE
| | - Ali H Eid
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
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Zhao Y, Xiong X, Sun Y. Cullin-RING Ligase 5: Functional characterization and its role in human cancers. Semin Cancer Biol 2020; 67:61-79. [PMID: 32334051 DOI: 10.1016/j.semcancer.2020.04.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/06/2020] [Accepted: 04/12/2020] [Indexed: 12/12/2022]
Abstract
Cullin-RING ligase 5 (CRL5) is a multi-protein complex and consists of a scaffold protien cullin 5, a RING protein RBX2 (also known as ROC2 or SAG), adaptor proteins Elongin B/C, and a substrate receptor protein SOCS. Through targeting a variety of substrates for proteasomal degradation or modulating various protein-protein interactions, CRL5 is involved in regulation of many biological processes, such as cytokine signal transduction, inflammation, viral infection, and oncogenesis. As many substrates of CRL5 are well-known oncoproteins or tumor suppressors, abnormal regulation of CRL5 is commonly found in human cancers. In this review, we first briefly introduce each of CRL5 components, and then discuss the biological processes regulated by four members of SOCS-box-containing substrate receptor family through substrate degradation. We next describe how CRL5 is hijacked by a variety of viral proteins to degrade host anti-viral proteins, which facilitates virus infection. We further discuss the regulation of CUL5 and its various roles in human cancers, acting as either a tumor suppressor or an oncoprotein in a context-dependent manner. Finally, we propose novel insights for future perspectives on the validation of cullin5 and other CRL5 components as potential targets, and possible targeting strategies to discover CRL5 inhibitors for anti-cancer and anti-virus therapies.
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Affiliation(s)
- Yongchao Zhao
- Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China.
| | - Xiufang Xiong
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China; Cancer Institute of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Sun
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China; Cancer Institute of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
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3
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Okumura F, Joo-Okumura A, Nakatsukasa K, Kamura T. The role of cullin 5-containing ubiquitin ligases. Cell Div 2016; 11:1. [PMID: 27030794 PMCID: PMC4812663 DOI: 10.1186/s13008-016-0016-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/02/2016] [Indexed: 01/01/2023] Open
Abstract
The suppressor of cytokine signaling (SOCS) box consists of the BC box and the cullin 5 (Cul5) box, which interact with Elongin BC and Cul5, respectively. SOCS box-containing proteins have ubiquitin ligase activity mediated by the formation of a complex with the scaffold protein Cul5 and the RING domain protein Rbx2, and are thereby members of the cullin RING ligase superfamily. Cul5-type ubiquitin ligases have a variety of substrates that are targeted for polyubiquitination and proteasomal degradation. Here, we review the current knowledge on the identification of Cul5 and the regulation of its expression, as well as the signaling pathways regulated by Cul5 and how viruses highjack the Cul5 system to overcome antiviral responses.
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Affiliation(s)
- Fumihiko Okumura
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602 Japan
| | - Akiko Joo-Okumura
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602 Japan
| | - Kunio Nakatsukasa
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602 Japan
| | - Takumi Kamura
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602 Japan
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Burnatowska-Hledin MA, Barney CC. New insights into the mechanism for VACM-1/cul5 expression in vascular tissue in vivo. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 313:79-101. [PMID: 25376490 DOI: 10.1016/b978-0-12-800177-6.00003-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Vasopressin-activated calcium-mobilizing (VACM-1)/cul5 is the least conserved member of a cullin protein family involved in the formation of E3-specific ligase complexes that are responsible for delivering the ubiquitin protein to their target substrate proteins selected for ubiquitin-dependent degradation. This chapter summarizes work to date that has focused on VACM-1/cul5's tissue-specific expression in vivo and on its potential role in the control of specific cellular signaling pathways in those structures. As mammalian cells may contain hundreds of E3 ligases, identification VACM-1/cul5 as a specific subunit of the system that is expressed in the endothelium and in collecting tubules, structures known for their control of cellular permeability, may have significant implications when designing studies to elucidate the mechanism of water conservation. For example, VACM-1/cul5 expression is affected by water deprivation in some tissues and there is a potential relationship between neddylated VACM-1/cul5 and aquaporins.
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Affiliation(s)
- Maria A Burnatowska-Hledin
- Department of Biology, Hope College, Holland, MI, USA; Department of Chemistry, Hope College, Holland, MI, USA
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Wang S, Wei W, Zheng Y, Hou J, Dou Y, Zhang S, Luo X, Cai X. The role of insulin C-peptide in the coevolution analyses of the insulin signaling pathway: a hint for its functions. PLoS One 2012; 7:e52847. [PMID: 23300796 PMCID: PMC3531361 DOI: 10.1371/journal.pone.0052847] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Accepted: 11/21/2012] [Indexed: 12/16/2022] Open
Abstract
As the linker between the A chain and B chain of proinsulin, C-peptide displays high variability in length and amino acid composition, and has been considered as an inert byproduct of insulin synthesis and processing for many years. Recent studies have suggested that C-peptide can act as a bioactive hormone, exerting various biological effects on the pathophysiology and treatment of diabetes. In this study, we analyzed the coevolution of insulin molecules among vertebrates, aiming at exploring the evolutionary characteristics of insulin molecule, especially the C-peptide. We also calculated the correlations of evolutionary rates between the insulin and the insulin receptor (IR) sequences as well as the domain-domain pairs of the ligand and receptor by the mirrortree method. The results revealed distinctive features of C-peptide in insulin intramolecular coevolution and correlated residue substitutions, which partly supported the idea that C-peptide can act as a bioactive hormone, with significant sequence features, as well as a linker assisting the formation of mature insulin during synthesis. Interestingly, the evolution of C-peptide exerted the highest correlation with that of the insulin receptor and its ligand binding domain (LBD), implying a potential relationship with the insulin signaling pathway.
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Affiliation(s)
- Shuai Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Zoonoses of CAAS, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Wei Wei
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Zoonoses of CAAS, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Yadong Zheng
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Zoonoses of CAAS, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Junling Hou
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Zoonoses of CAAS, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Yongxi Dou
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Zoonoses of CAAS, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Shaohua Zhang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Zoonoses of CAAS, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Xuenong Luo
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Zoonoses of CAAS, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
- * E-mail: (XL); (XC)
| | - Xuepeng Cai
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Zoonoses of CAAS, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
- * E-mail: (XL); (XC)
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Le IP, Schultz S, Andresen BT, Dewey GL, Zhao P, Listenberger L, Deen PM, Buchwalter A, Barney CC, Burnatowska-Hledin MA. Aquaporin-2 Levelsin vitroandin vivoare Regulated by VACM-1, a Cul 5 Gene. Cell Physiol Biochem 2012; 30:1148-58. [DOI: 10.1159/000343305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2012] [Indexed: 11/19/2022] Open
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Lindahl E, Nordquist L, Müller P, El Agha E, Friederich M, Dahlman-Wright K, Palm F, Jörnvall H. Early transcriptional regulation by C-peptide in freshly isolated rat proximal tubular cells. Diabetes Metab Res Rev 2011; 27:697-704. [PMID: 21618400 DOI: 10.1002/dmrr.1220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 03/06/2011] [Accepted: 05/17/2011] [Indexed: 12/17/2022]
Abstract
BACKGROUND Clinical studies have shown that proinsulin C-peptide exerts renoprotective effects in type 1 diabetes, although the underlying mechanisms are poorly understood. As C-peptide has been shown to induce several intracellular events and to localize to nuclei, we aimed to determine whether gene transcription is affected in proximal tubular kidney cells, and if so, whether the genes with altered transcription include those related to protective mechanisms. METHODS The effect of C-peptide incubation (2 h) on gene expression was investigated in freshly isolated proximal tubular cells from streptozotocin-diabetic Sprague-Dawley rats using global gene expression profiling and real-time quantitative polymerase chain reaction. Protein expression was assayed using western blotting. Different bioinformatic strategies were employed. RESULTS Gene transcription profiling demonstrated differential transcription of 492 genes (p < 0.01) after 2 h of C-peptide exposure, with the majority of these genes repressed (83%). Real-time quantitative polymerase chain reaction validation supported a trend of several G protein-coupled receptors being activated, and certain transcription factors being repressed. Also, C-peptide repressed the transcription of genes associated with the pathways of circulatory and inflammatory diseases. CONCLUSION This study shows that C-peptide exerts early effects on gene transcription in proximal tubular cells. The findings also bring further knowledge to the renoprotective mechanisms of C-peptide in type 1 diabetes, and support a transcriptional activity for C-peptide. It is suggested that C-peptide may play a regulatory role in the gene expression of proximal tubular cells.
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Affiliation(s)
- Emma Lindahl
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Nordquist L, Shimada K, Ishii T, Furuya DT, Kamikawa A, Kimura K. Proinsulin C-peptide prevents type-1 diabetes-induced decrease of renal Na+-K+-ATPase alpha1-subunit in rats. Diabetes Metab Res Rev 2010; 26:193-9. [PMID: 20225182 DOI: 10.1002/dmrr.1071] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS C-peptide reduces renal damage in diabetic patients and experimental animal models. In vitro studies suggest that the renal effects of C-peptide may, in part, be explained by stimulation of Na(+)/K(+)-ATPase activity. However, the responses of Na(+)/K(+)-ATPase expression in the kidney of diabetic animals to C-peptide administration remain unclear. The aim of this study was to clarify the responses. METHODS Type 1 diabetic rats were produced by injecting streptozotocin (STZ), and some of the rats were treated with either C-peptide or insulin by the aid of an osmotic pump for 1 week. The mRNA expression and immunohistochemical localization of Na(+)/K(+)-ATPase alpha1-, alpha2- and beta3-subunits were investigated in the kidney of these rats. RESULTS Na(+)/K(+)-ATPase alpha1-subunit was abundantly expressed in the medullary collecting ducts of control animals, but the expression was markedly decreased in the diabetic state with concomitant decrease in its mRNA expression. Similar decreases were observed in the insulin-treated diabetic rats, whereas in the C-peptide-treated diabetic rats, there was no reduction in the alpha1-expression. The beta3-subunit was expressed in podocytes and parietal cells in the glomeruli, vascular endothelial cells, and cortical collecting ducts, but lesser signals were observed in the proximal and distal tubules. However, the beta3-subunit did not appear to be affected by the diabetic state. CONCLUSIONS Diabetes selectively reduced Na(+)/K(+)-ATPase alpha1-subunit expression and abundance. Chronic administration of C-peptide prevented this decrease. This implies a role for C-peptide in the long-term regulation of Na(+)/K(+)-ATPase function.
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Affiliation(s)
- Lina Nordquist
- Laboratory of Biochemistry, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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Abstract
Although long believed to be inert, C-peptide has now been shown to have definite biological effects both in vitro and in vivo in diabetic animals and in patients with type 1 diabetes. These effects point to a protective action of C-peptide against the development of diabetic microvascular complications. Underpinning these observations is undisputed evidence of C-peptide binding to a variety of cell types at physiologically relevant concentrations, and the downstream stimulation of multiple cell signaling pathways and gene transcription via the activation of numerous transcription factors. These pathways affect such fundamental cellular processes as re-absorptive and/or secretory phenotype, migration, growth, and survival. Whilst the receptor remains to be identified, experimental data points strongly to the existence of a specific G-protein-coupled receptor for C-peptide. Of the cell types studied so far, kidney tubular cells express the highest number of C-peptide binding sites. Accordingly, C-peptide exerts major effects on the function of these cells, and in the context of diabetic nephropathy appears to antagonise the pathophysiological effects of major disease mediators such as TGFbeta1 and TNFalpha. Therefore, based on its cellular activity profile C-peptide appears well positioned for development as a therapeutic tool to treat microvascular complications in type 1 diabetes.
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Affiliation(s)
- Claire E Hills
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
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Intracellular signalling by C-peptide. EXPERIMENTAL DIABETES RESEARCH 2008; 2008:635158. [PMID: 18382618 PMCID: PMC2276616 DOI: 10.1155/2008/635158] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Accepted: 02/06/2008] [Indexed: 12/11/2022]
Abstract
C-peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C-peptide when administered to individuals with type I diabetes. Data indicate that C-peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G-protein coupled. Binding of C-peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI-3-kinase activity, stimulation of the Na(+)/K(+) ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C-peptide may serve as a potential therapeutic agent for the treatment or prevention of long-term complications associated with diabetes.
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Luzi L, Zerbini G, Caumo A. C-peptide: a redundant relative of insulin? Diabetologia 2007; 50:500-2. [PMID: 17225123 DOI: 10.1007/s00125-006-0576-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Accepted: 10/24/2006] [Indexed: 12/13/2022]
Affiliation(s)
- L Luzi
- Section of Nutrition and Metabolism, San Raffaele Scientific Institute, 20132, Milan, Italy.
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