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Kim J, Yang Y, Choi E, Lee S, Choi J. Effects of C-Peptide on Dexamethasone-Induced In Vitro and In Vivo Models as a Potential Therapeutic Agent for Muscle Atrophy. Int J Mol Sci 2023; 24:15433. [PMID: 37895113 PMCID: PMC10607908 DOI: 10.3390/ijms242015433] [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: 09/14/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
This study aimed to investigate the effects of C-peptide on C2C12 myotubes and a mouse model. Both in vitro and in vivo experiments were conducted to elucidate the role of C-peptide in muscle atrophy. Various concentrations (0, 0.01, 0.1, 1, 10, and 100 nM) of C-peptide were used on the differentiated C2C12 myotubes with or without dexamethasone (DEX). C57BL/6J mice were administered with C-peptide and DEX for 8 days, followed by C-peptide treatment for 12 days. Compared to the DEX group, C-peptide increased the fusion and differentiation indices and suppressed atrophic factor expression in C2C12 myotubes. However, 100 nM C-peptide decreased the fusion and differentiation indices and increased atrophic factor expression regardless of DEX treatment. In C57BL/6J mice, DEX + C-peptide co-treatment significantly attenuated the body and muscle weight loss and improved the grip strength and cross-sectional area of the gastrocnemius (Gas) and quadriceps (Quad) muscles. C-peptide downregulated the mRNA and protein levels of muscle degradation-related markers, particularly Atrogin-1, in Gas and Quad muscles. This study underscores the potential of C-peptides in mitigating muscle weight reduction and preserving muscle function during muscle atrophy via molecular regulation. In addition, the work presents basic data for future studies on the effect of C-peptide on diabetic muscular dystrophy.
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Affiliation(s)
- Jinjoo Kim
- Department of Food and Nutrition, College of Natural Science and Public Health and Safety, Chosun University, Gwangju 61452, Republic of Korea; (J.K.); (E.C.); (S.L.)
| | - Youngmo Yang
- Department of Pharmacy, College of Pharmacy, Chosun University, Gwangju 61452, Republic of Korea;
| | - Eunwon Choi
- Department of Food and Nutrition, College of Natural Science and Public Health and Safety, Chosun University, Gwangju 61452, Republic of Korea; (J.K.); (E.C.); (S.L.)
| | - Sumin Lee
- Department of Food and Nutrition, College of Natural Science and Public Health and Safety, Chosun University, Gwangju 61452, Republic of Korea; (J.K.); (E.C.); (S.L.)
| | - Jiyoung Choi
- Department of Food and Nutrition, College of Natural Science and Public Health and Safety, Chosun University, Gwangju 61452, Republic of Korea; (J.K.); (E.C.); (S.L.)
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Yang H, Bai J, Li L, Yang Y, Zhang Y, Lv H, Fu S. Association of C-peptide level with bone mineral density in type 2 diabetes mellitus. Osteoporos Int 2023:10.1007/s00198-023-06785-9. [PMID: 37204453 DOI: 10.1007/s00198-023-06785-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 05/01/2023] [Indexed: 05/20/2023]
Abstract
This study revealed that there was no significant linear relationship between fasting C-peptide (FCP) level and bone mineral density (BMD) or fracture risk in type 2 diabetes mellitus (T2DM) patients. However, in the FCP ≤ 1.14 ng/ml group, FCP is positively correlated with whole body (WB), lumbar spine (LS), and femoral neck (FN) BMD and negatively correlated with fracture risk. PURPOSE To explore the relationship between C-peptide and BMD and fracture risk in T2DM patients. METHODS 530 T2DM patients were enrolled and divided into three groups by FCP tertiles, and the clinical data were collected. BMD was measured by dual-energy X-ray absorptiometry (DXA). The 10-year probability of major osteoporotic fractures (MOFs) and hip fractures (HFs) was evaluated by adjusted fracture risk assessment tool (FRAX). RESULTS In the FCP ≤ 1.14 ng/ml group, FCP level was positively correlated with WB, LS, and FN BMD, while FCP was negatively correlated with fracture risk and osteoporotic fracture history. However, FCP was not correlated with BMD and fracture risk and osteoporotic fracture history in the 1.14 < FCP ≤ 1.73 ng/ml and FCP > 1.73 ng/ml groups. The study has shown that FCP was an independent factor influencing BMD and fracture risk in the FCP ≤ 1.14 ng/ml group. CONCLUSIONS There is no significant linear relationship between FCP level and BMD or fracture risk in T2DM patients. In the FCP ≤ 1.14 ng/ml group, FCP is positively correlated with WB, LS, and FN BMD and negatively correlated with fracture risk, and FCP is an independent influencing factor of BMD and fracture risk. The findings suggest that FCP may predict the risk of osteoporosis or fracture in some T2DM patients, which has a certain clinical value.
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Affiliation(s)
- Hong Yang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, China
| | - Jia Bai
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, China
| | - Lingling Li
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, China
| | - Ying Yang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, China
| | - Yangyang Zhang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, China
| | - Haihong Lv
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, Gansu, China.
| | - Songbo Fu
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, Gansu, China
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Zhou J, Yuan Y, Li X. The association between C-peptide and atrial cardiomyopathy in nondiabetic adults: results from NHANES III. Heart Vessels 2023:10.1007/s00380-023-02259-4. [PMID: 36928669 DOI: 10.1007/s00380-023-02259-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/01/2023] [Indexed: 03/18/2023]
Abstract
Serum C-peptide exhibits various biological activities. The relationship between C-peptide and atrial cardiomyopathy remains unknown. We aimed to investigate the association between C-peptide level and atrial cardiomyopathy in nondiabetic adults. Our study enrolled 4578 participants without diagnosed diabetes from the Third National Health and Nutrition Examination Survey (NHANES III). Atrial cardiomyopathy was defined as a deep terminal negative P wave in V1 below - 100 µV (more negative), according to the electrocardiogram. The participants were categorized into low C-peptide (≤ 1.46 nmol/L) and high C-peptide (> 1.46 nmol/L) groups, according to the receiver operating characteristic analysis. Odds ratio (OR) and 95% confidence interval (CI) for the association between C-peptide level and atrial cardiomyopathy were generated using multivariate logistic regression analysis. The prevalence of atrial cardiomyopathy was higher in the high C-peptide group than in the low C-peptide group (5.62% vs. 2.31%, P < 0.001, respectively). Multivariate logistic regression analysis showed that participants in the high C-peptide group had a 3.60-fold (95% CI 1.81-6.99) higher risk of atrial cardiomyopathy than those in the low C-peptide group. Per standard deviation increase in C-peptide was linked to a 1.20-fold (95% CI 1.00-1.41) higher risk in atrial cardiomyopathy. High C-peptide level might be an independent risk factor for atrial cardiomyopathy in nondiabetic adults.
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Affiliation(s)
- Jingliang Zhou
- Department of Cardiology, Peking University People's Hospital, 11Th South Street, Xicheng District, Beijing, 100044, China
| | - Yanping Yuan
- Department of Endocrinology, Peking University People's Hospital, Beijing, 100044, China
| | - Xuebin Li
- Department of Cardiology, Peking University People's Hospital, 11Th South Street, Xicheng District, Beijing, 100044, China.
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Nepal N, Arthur S, Butts MR, Singh S, Palaniappan B, Sundaram U. Molecular Mechanism of Stimulation of Na-K-ATPase by Leukotriene D4 in Intestinal Epithelial Cells. Int J Mol Sci 2021; 22:ijms22147569. [PMID: 34299188 PMCID: PMC8303499 DOI: 10.3390/ijms22147569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 12/03/2022] Open
Abstract
Na-K-ATPase provides a favorable transcellular Na gradient required for the functioning of Na-dependent nutrient transporters in intestinal epithelial cells. The primary metabolite for enterocytes is glutamine, which is absorbed via Na-glutamine co-transporter (SN2; SLC38A5) in intestinal crypt cells. SN2 activity is stimulated during chronic intestinal inflammation, at least in part, secondarily to the stimulation of Na-K-ATPase activity. Leukotriene D4 (LTD4) is known to be elevated in the mucosa during chronic enteritis, but the way in which it may regulate Na-K-ATPase is not known. In an in vitro model of rat intestinal epithelial cells (IEC-18), Na-K-ATPase activity was significantly stimulated by LTD4. As LTD4 mediates its action via Ca-dependent protein kinase C (PKC), Ca levels were measured and were found to be increased. Phorbol 12-myristate 13-acetate (PMA), an activator of PKC, also mediated stimulation of Na-K-ATPase like LTD4, while BAPTA-AM (Ca chelator) and calphostin-C (Cal-C; PKC inhibitor) prevented the stimulation of Na-K-ATPase activity. LTD4 caused a significant increase in mRNA and plasma membrane protein expression of Na-K-ATPase α1 and β1 subunits, which was prevented by calphostin-C. These data demonstrate that LTD4 stimulates Na-K-ATPase in intestinal crypt cells secondarily to the transcriptional increase of Na-K-ATPase α1 and β1 subunits, mediated via the Ca-activated PKC pathway.
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Biological Activity of c-Peptide in Microvascular Complications of Type 1 Diabetes-Time for Translational Studies or Back to the Basics? Int J Mol Sci 2020; 21:ijms21249723. [PMID: 33419247 PMCID: PMC7766542 DOI: 10.3390/ijms21249723] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/15/2022] Open
Abstract
People with type 1 diabetes have an increased risk of developing microvascular complications, which have a negative impact on the quality of life and reduce life expectancy. Numerous studies in animals with experimental diabetes show that c-peptide supplementation exerts beneficial effects on diabetes-induced damage in peripheral nerves and kidneys. There is substantial evidence that c-peptide counteracts the detrimental changes caused by hyperglycemia at the cellular level, such as decreased activation of endothelial nitric oxide synthase and sodium potassium ATPase, and increase in formation of pro-inflammatory molecules mediated by nuclear factor kappa-light-chain-enhancer of activated B cells: cytokines, chemokines, cell adhesion molecules, vascular endothelial growth factor, and transforming growth factor beta. However, despite positive results from cell and animal studies, no successful c-peptide replacement therapies have been developed so far. Therefore, it is important to improve our understanding of the impact of c-peptide on the pathophysiology of microvascular complications to develop novel c-peptide-based treatments. This article aims to review current knowledge on the impact of c-peptide on diabetic neuro- and nephropathy and to evaluate its potential therapeutic role.
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Ferrannini E, Pereira-Moreira R, Seghieri M, Rebelos E, Souza AL, Chueire VB, Arvia C, Muscelli E. Insulin enhances renal glucose excretion: relation to insulin sensitivity and sodium-glucose cotransport. BMJ Open Diabetes Res Care 2020; 8:8/1/e001178. [PMID: 32423964 PMCID: PMC7245398 DOI: 10.1136/bmjdrc-2020-001178] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/27/2020] [Accepted: 03/24/2020] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Insulin regulates renal glucose production and utilization; both these fluxes are increased in type 2 diabetes (T2D). Whether insulin also controls urinary glucose excretion is not known. METHODS We applied the pancreatic clamp technique in 12 healthy subjects and 13 T2D subjects. Each participant received a somatostatin infusion and a variable glucose infusion to achieve (within 1 hour) and maintain glycemia at 22 mmol/L for 3 hours; next, a constant insulin infusion (240 pmol/min/kg) was added for another 3 hours. Urine was collected separately in each period for glucose and creatinine determination. RESULTS During saline, glucose excretion was lower in T2D than controls in absolute terms (0.49 (0.32) vs 0.69 (0.18) mmol/min, median (IQR), p=0.01) and as a fraction of filtered glucose (16.2 (6.4) vs 19.9 (7.5)%, p<0.001). With insulin, whole-body glucose disposal rose more in controls than T2D (183 (48) vs 101 (48) µmol/kgFFM/min, p<0.0003). Insulin stimulated absolute and fractional glucose excretion in controls (p<0.01) but not in T2D. Sodium excretion paralleled glucose excretion. In the pooled data, fractional glucose excretion was directly related to whole-body glucose disposal and to fractional sodium excretion (r=0.52 and 0.54, both p<0.01). In another group of healthy controls, empagliflozin was administered before starting the pancreatic clamp to block sodium-glucose cotransporter 2 (SGLT2). Under these conditions, insulin still enhanced both glucose and sodium excretion. CONCLUSIONS Acute exogenous insulin infusion jointly stimulates renal glucose and sodium excretion, indicating that the effect may be mediated by SGLTs. This action is resistant in patients with diabetes, accounting for their increased retention of glucose and sodium, and is not abolished by partial SGLT2 inhibition by empagliflozin.
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Affiliation(s)
| | - Ricardo Pereira-Moreira
- Department of Internal Medicine, School of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Marta Seghieri
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Eleni Rebelos
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Aglécio L Souza
- Department of Internal Medicine, School of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Valeria B Chueire
- Department of Internal Medicine, School of Medical Sciences, University of Campinas, Campinas, Brazil
| | | | - Elza Muscelli
- Department of Internal Medicine, School of Medical Sciences, University of Campinas, Campinas, Brazil
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Pereira-Moreira R, Muscelli E. Effect of Insulin on Proximal Tubules Handling of Glucose: A Systematic Review. J Diabetes Res 2020; 2020:8492467. [PMID: 32377524 PMCID: PMC7180501 DOI: 10.1155/2020/8492467] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 12/18/2019] [Accepted: 12/27/2019] [Indexed: 02/06/2023] Open
Abstract
Renal proximal tubules reabsorb glucose from the glomerular filtrate and release it back into the circulation. Modulation of glomerular filtration and renal glucose disposal are some of the insulin actions, but little is known about a possible insulin effect on tubular glucose reabsorption. This review is aimed at synthesizing the current knowledge about insulin action on glucose handling by proximal tubules. Method. A systematic article selection from Medline (PubMed) and Embase between 2008 and 2019. 180 selected articles were clustered into topics (renal insulin handling, proximal tubule glucose transport, renal gluconeogenesis, and renal insulin resistance). Summary of Results. Insulin upregulates its renal uptake and degradation, and there is probably a renal site-specific insulin action and resistance; studies in diabetic animal models suggest that insulin increases renal SGLT2 protein content; in vivo human studies on glucose transport are few, and results of glucose transporter protein and mRNA contents are conflicting in human kidney biopsies; maximum renal glucose reabsorptive capacity is higher in diabetic patients than in healthy subjects; glucose stimulates SGLT1, SGLT2, and GLUT2 in renal cell cultures while insulin raises SGLT2 protein availability and activity and seems to directly inhibit the SGLT1 activity despite it activating this transporter indirectly. Besides, insulin regulates SGLT2 inhibitor bioavailability, inhibits renal gluconeogenesis, and interferes with Na+K+ATPase activity impacting on glucose transport. Conclusion. Available data points to an important insulin participation in renal glucose handling, including tubular glucose transport, but human studies with reproducible and comparable method are still needed.
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Affiliation(s)
- Ricardo Pereira-Moreira
- Department of Internal Medicine, School of Medical Sciences, University of Campinas, Zip Code: 13083-887, Brazil
| | - Elza Muscelli
- Department of Internal Medicine, School of Medical Sciences, University of Campinas, Zip Code: 13083-887, Brazil
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The effect of C-peptide on diabetic nephropathy: A review of molecular mechanisms. Life Sci 2019; 237:116950. [PMID: 31605709 DOI: 10.1016/j.lfs.2019.116950] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 02/07/2023]
Abstract
C-peptide is a small peptide connecting two chains of proinsulin molecule and is dissociated before the release of insulin. It is secreted in an equimolar amount to insulin from the pancreatic beta-cells into the circulation. Recent evidence demonstrates that it has other physiologic activities beyond its structural function. C-peptide modulates intracellular signaling pathways in various pathophysiologic states and, could potentially be a new therapeutic target for different disorders including diabetic complications. There is growing evidence that c-peptide has modulatory effects on the molecular mechanisms involved in the development of diabetic nephropathy. Although we have little direct evidence, pharmacological properties of c-peptide suggest that it can provide potent renoprotective effects especially, in a c-peptide deficient milieu as in type 1 diabetes mellitus. In this review, we describe possible molecular mechanisms by which c-peptide may improve renal efficiency in a diabetic milieu.
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Martin JH, Aitken RJ, Bromfield EG, Cafe SL, Sutherland JM, Frost ER, Nixon B, Lord T. Investigation into the presence and functional significance of proinsulin C-peptide in the female germline†. Biol Reprod 2019; 100:1275-1289. [PMID: 30715203 DOI: 10.1093/biolre/ioz008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 12/10/2018] [Accepted: 01/28/2019] [Indexed: 08/02/2024] Open
Abstract
Diabetes is associated with poor oocyte quality and the dysregulation of ovarian function and is thus a leading contributor to the increasing prevalence of female reproductive pathologies. Accordingly, it is well-established that insulin fulfills a key role in the regulation of several facets of female reproduction. What remains less certain is whether proinsulin C-peptide, which has recently been implicated in cellular signaling cascades, holds a functional role in the female germline. In the present study, we examined the expression of insulin, C-peptide, and its purported receptor; GPR146, within the mouse ovary and oocyte. Our data establish the presence of abundant C-peptide within follicular fluid and raise the prospect that this bioactive peptide is internalized by oocytes in a G-protein coupled receptor-dependent manner. Further, our data reveal that internalized C-peptide undergoes pronounced subcellular relocalization from the ooplasm to the pronuclei postfertilization. The application of immunoprecipitation analysis and mass spectrometry identified breast cancer type 2 susceptibility protein (BRCA2), the meiotic resumption/DNA repair protein, as a primary binding partner for C-peptide within the oocyte. Collectively, these findings establish a novel accumulation profile for C-peptide in the female germline and provide the first evidence for an interaction between C-peptide and BRCA2. This interaction is particularly intriguing when considering the propensity for oocytes from diabetic women to experience aberrant meiotic resumption and perturbation of traditional DNA repair processes. This therefore provides a clear imperative for further investigation of the implications of dysregulated C-peptide production in these individuals.
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Affiliation(s)
- Jacinta H Martin
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The Hunter Medical Research Institute, New Lambton Heights and the University of Newcastle, Callaghan, Newcastle, Australia
| | - R John Aitken
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The Hunter Medical Research Institute, New Lambton Heights and the University of Newcastle, Callaghan, Newcastle, Australia
| | - Elizabeth G Bromfield
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The Hunter Medical Research Institute, New Lambton Heights and the University of Newcastle, Callaghan, Newcastle, Australia
| | - Shenae L Cafe
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The Hunter Medical Research Institute, New Lambton Heights and the University of Newcastle, Callaghan, Newcastle, Australia
| | - Jessie M Sutherland
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The Hunter Medical Research Institute, New Lambton Heights and the University of Newcastle, Callaghan, Newcastle, Australia
| | - Emily R Frost
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The Hunter Medical Research Institute, New Lambton Heights and the University of Newcastle, Callaghan, Newcastle, Australia
| | - Brett Nixon
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The Hunter Medical Research Institute, New Lambton Heights and the University of Newcastle, Callaghan, Newcastle, Australia
| | - Tessa Lord
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The Hunter Medical Research Institute, New Lambton Heights and the University of Newcastle, Callaghan, Newcastle, Australia
- School of Molecular Biosciences, Centre for Reproductive Biology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
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Li Z, Mbah NE, Overmeyer JH, Sarver JG, George S, Trabbic CJ, Erhardt PW, Maltese WA. The JNK signaling pathway plays a key role in methuosis (non-apoptotic cell death) induced by MOMIPP in glioblastoma. BMC Cancer 2019; 19:77. [PMID: 30651087 PMCID: PMC6335761 DOI: 10.1186/s12885-019-5288-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 01/07/2019] [Indexed: 12/12/2022] Open
Abstract
Background Synthetic indolyl- pyridinyl- propenones (IPPs) induce methuosis, a form of non-apoptotic cell death, in glioblastoma and other cancer cell lines. Methuosis is characterized by accumulation of cytoplasmic vacuoles derived from macropinosomes and late endosomes, followed by metabolic failure and rupture of the plasma membrane. However, not all IPPs that cause vacuolization are cytotoxic. The main goals of the present study were to identify key signaling pathways that contribute to methuosis induced by cytotoxic IPPs and to evaluate the anti-tumor potential of a prototype IPP in vivo. Methods We utilized metabolic flux analysis, glucose uptake, immunoblotting, and selective pharmacological inhibitors to compare the effects of closely related cytotoxic and non-cytotoxic IPPs in cultured glioblastoma cells. To determine whether the use of methuosis-inducing IPPs might be feasible in a therapeutic context, we quantified the distribution of our lead IPP compound, MOMIPP, in mouse plasma and brain, and tested its ability to inhibit tumor growth in an intracerebral glioblastoma xenograft model. Results The cytotoxic IPP compound, MOMIPP, causes early disruptions of glucose uptake and glycolytic metabolism. Coincident with these metabolic changes, MOMIPP selectively activates the JNK1/2 stress kinase pathway, resulting in phosphorylation of c-Jun, Bcl-2 and Bcl-xL. At the same concentration, the non-cytotoxic analog, MOPIPP, does not activate these pathways. Pharmacologic inhibition of JNK activity promotes survival, even when cells are extensively vacuolated, but suppression of c-Jun transcriptional activity offers no protection. MOMIPP readily penetrates the blood-brain barrier and is moderately effective in suppressing progression of intracerebral glioblastoma xenografts. Conclusions The results suggest that interference with glucose uptake and induction of JNK-mediated phosphorylation of pro-survival members of the Bcl-2 family represent key events in the methuosis death process. In addition to providing new insights into the underlying molecular mechanism of methuosis, the results indicate that compounds of the cytotoxic IPP class may have potential for further development as therapeutic agents for brain tumors. Electronic supplementary material The online version of this article (10.1186/s12885-019-5288-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zehui Li
- Department of Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, 43614, United States
| | - Nneka E Mbah
- Department of Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, 43614, United States
| | - Jean H Overmeyer
- Department of Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, 43614, United States
| | - Jeffrey G Sarver
- Center for Drug Design and Development, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, 43606, USA
| | - Sage George
- Department of Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, 43614, United States
| | - Christopher J Trabbic
- Center for Drug Design and Development, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, 43606, USA
| | - Paul W Erhardt
- Center for Drug Design and Development, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, 43606, USA
| | - William A Maltese
- Department of Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, 43614, United States.
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Täubel J, Ferber G, Van Langenhoven L, Del Bianco T, Fernandes S, Djumanov D, Kanters JK, Graff C, Camm AJ. The Cardiovascular Effects of a Meal: J-T peak and T peak -T end Assessment and Further Insights Into the Physiological Effects. J Clin Pharmacol 2019; 59:799-810. [PMID: 30633366 PMCID: PMC6590239 DOI: 10.1002/jcph.1374] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/14/2018] [Indexed: 12/13/2022]
Abstract
Meal intake leads to a significant and prolonged increase in cardiac output to supply the splanchnic vasculature. A meal is associated with sympathetic activation of the cardiovascular system, and food ingestion is correlated with an increase in heart rate, an increase in cardiac stroke volume, and QTc interval shortening for up to 7 hours. Given the complexity of the system, one or several of many mechanisms could explain this observation. The shortening of the QTc interval was correlated with a rise of C‐peptide following food ingestion, but the mechanisms by which C‐peptide may be involved in the modulation of cardiac repolarization are still unknown. This shortening of the myocardial action potential caused by the ingestion of food was further investigated in the present study by measuring the QRS, J‐Tpeak, and Tpeak‐Tend intervals in search of further clues to better understand the underlying mechanisms. A retrospective analysis was conducted based on data collected in a formal thorough QT/QTc study in which 32 subjects received a carbohydrate‐rich “continental” breakfast, moxifloxacin without food, and moxifloxacin with food. We assessed the effect of food on T‐wave morphology using validated algorithms for measurement of J‐Tpeak and Tpeak‐Tend intervals. Our findings demonstrate that a standardized meal significantly shortened J‐Tpeak for 4 hours after a meal and to a much lesser extent and shorter duration (up to 1 hour) prolonged the Tpeak‐Tend and QRS intervals. This suggests that the QTc shortening occurs mainly during phase 2 of the cardiac action potential. As there was no corresponding effect on Tpeak‐Tend beyond the first hour, we conclude that a meal does not interfere with the outward correcting potassium channels but possibly with Ca2+ currents. An effect on mainly Ca2+ aligns well with our understanding of physiology whereby an increase in stroke volume, as observed after a meal, is associated with changes in Ca2+ cycling in and out of the sarcoplasmic reticulum during cardiac myocyte contraction.
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Affiliation(s)
- Jörg Täubel
- Richmond Pharmacology Ltd., St George's University of London, Cranmer Terrace, London, UK.,Cardiovascular and Cell Sciences Research Institute, St George's University of London, London, UK
| | - Georg Ferber
- Statistik Georg Ferber GmbH, Cagliostrostrasse, Riehen, Switzerland
| | - Leen Van Langenhoven
- Richmond Pharmacology Ltd., St George's University of London, Cranmer Terrace, London, UK
| | - Teresa Del Bianco
- Richmond Pharmacology Ltd., St George's University of London, Cranmer Terrace, London, UK
| | - Sara Fernandes
- Richmond Pharmacology Ltd., St George's University of London, Cranmer Terrace, London, UK
| | - Dilshat Djumanov
- Richmond Pharmacology Ltd., St George's University of London, Cranmer Terrace, London, UK
| | - Jørgen K Kanters
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Claus Graff
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - A John Camm
- Cardiovascular and Cell Sciences Research Institute, St George's University of London, London, UK
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12
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Poupeau A, Garde C, Sulek K, Citirikkaya K, Treebak JT, Arumugam M, Simar D, Olofsson LE, Bäckhed F, Barrès R. Genes controlling the activation of natural killer lymphocytes are epigenetically remodeled in intestinal cells from germ-free mice. FASEB J 2018; 33:2719-2731. [PMID: 30303739 PMCID: PMC6338647 DOI: 10.1096/fj.201800787r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Remodeling of the gut microbiota is implicated in various metabolic and inflammatory diseases of the gastrointestinal tract. We hypothesized that the gut microbiota affects the DNA methylation profile of intestinal epithelial cells (IECs) which could, in turn, alter intestinal function. In this study, we used mass spectrometry and methylated DNA capture to respectively investigate global and genome-wide DNA methylation of intestinal epithelial cells from germ-free (GF) and conventionally raised mice. In colonic IECs from GF mice, DNA was markedly hypermethylated. This was associated with a dramatic loss of ten-eleven-translocation activity, a lower DNA methyltransferase activity and lower circulating levels of the 1-carbon metabolite, folate. At the gene level, we found an enrichment for differentially methylated regions proximal to genes regulating the cytotoxicity of NK cells (false-discovery rate < 8.9E−6), notably genes regulating the cross-talk between NK cells and target cells, such as members of the NK group 2 member D ligand superfamily Raet. This distinct epigenetic signature was associated with a marked decrease in Raet1 expression and a loss of CD56+/CD45+ cells in the intestine of GF mice. Thus, our results indicate that altered activity of methylation-modifying enzymes in GF mice influences the IEC epigenome and modulates the crosstalk between IECs and NK cells. Epigenetic reprogramming of IECs may modulate intestinal function in diseases associated with altered gut microbiota.—Poupeau, A., Garde, C., Sulek, K., Citirikkaya, K., Treebak, J. T., Arumugam, M., Simar, D., Olofsson, L. E., Bäckhed, F., Barrès, R. Genes controlling the activation of natural killer lymphocytes are epigenetically remodeled in intestinal cells from germ-free mice.
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Affiliation(s)
- Audrey Poupeau
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian Garde
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Karolina Sulek
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kiymet Citirikkaya
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas T Treebak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Manimozhiyan Arumugam
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - David Simar
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Mechanisms of Disease and Translational Research, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia; and
| | - Louise E Olofsson
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Fredrik Bäckhed
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Molecular and Clinical Medicine, Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Romain Barrès
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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13
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Affiliation(s)
- Jian Yang
- Department of Nutrition, Daping Hospital, The Third Military Medical University, Chongqing, China.,Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Pedro A Jose
- Division of Renal Disease & Hypertension, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
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Abstract
Kidney disease is a serious development in diabetes mellitus and poses an increasing clinical problem. Despite increasing incidence and prevalence of diabetic kidney disease, there have been no new therapies for this condition in the last 20 years. Mounting evidence supports a biological role for C-peptide, and findings from multiple studies now suggest that C-peptide may beneficially affect the disturbed metabolic and pathophysiological pathways leading to the development of diabetic nephropathy. Studies of C-peptide in animal models and in humans with type 1 diabetes all suggest a renoprotective effect for this peptide. In diabetic rodents, C-peptide reduces glomerular hyperfiltration and albuminuria. Cohort studies of diabetic patients with combined islet and kidney transplants suggest that maintained C-peptide secretion is protective of renal graft function. Further, in short-term studies of patients with type 1 diabetes, administration of C-peptide is also associated with a lowered hyperfiltration rate and reduced microalbuminuria. Thus, the available information suggests that type 1 diabetes should be regarded as a dual hormone deficiency disease and that clinical trials of C-peptide in diabetic nephropathy are both justified and urgently required.
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Affiliation(s)
- N J Brunskill
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
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15
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Pirkmajer S, Chibalin AV. Na,K-ATPase regulation in skeletal muscle. Am J Physiol Endocrinol Metab 2016; 311:E1-E31. [PMID: 27166285 DOI: 10.1152/ajpendo.00539.2015] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 05/02/2016] [Indexed: 12/17/2022]
Abstract
Skeletal muscle contains one of the largest and the most dynamic pools of Na,K-ATPase (NKA) in the body. Under resting conditions, NKA in skeletal muscle operates at only a fraction of maximal pumping capacity, but it can be markedly activated when demands for ion transport increase, such as during exercise or following food intake. Given the size, capacity, and dynamic range of the NKA pool in skeletal muscle, its tight regulation is essential to maintain whole body homeostasis as well as muscle function. To reconcile functional needs of systemic homeostasis with those of skeletal muscle, NKA is regulated in a coordinated manner by extrinsic stimuli, such as hormones and nerve-derived factors, as well as by local stimuli arising in skeletal muscle fibers, such as contractions and muscle energy status. These stimuli regulate NKA acutely by controlling its enzymatic activity and/or its distribution between the plasma membrane and the intracellular storage compartment. They also regulate NKA chronically by controlling NKA gene expression, thus determining total NKA content in skeletal muscle and its maximal pumping capacity. This review focuses on molecular mechanisms that underlie regulation of NKA in skeletal muscle by major extrinsic and local stimuli. Special emphasis is given to stimuli and mechanisms linking regulation of NKA and energy metabolism in skeletal muscle, such as insulin and the energy-sensing AMP-activated protein kinase. Finally, the recently uncovered roles for glutathionylation, nitric oxide, and extracellular K(+) in the regulation of NKA in skeletal muscle are highlighted.
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Affiliation(s)
- Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; and
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
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16
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Li Z, Langhans SA. Transcriptional regulators of Na,K-ATPase subunits. Front Cell Dev Biol 2015; 3:66. [PMID: 26579519 PMCID: PMC4620432 DOI: 10.3389/fcell.2015.00066] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 10/05/2015] [Indexed: 12/20/2022] Open
Abstract
The Na,K-ATPase classically serves as an ion pump creating an electrochemical gradient across the plasma membrane that is essential for transepithelial transport, nutrient uptake and membrane potential. In addition, Na,K-ATPase also functions as a receptor, a signal transducer and a cell adhesion molecule. With such diverse roles, it is understandable that the Na,K-ATPase subunits, the catalytic α-subunit, the β-subunit and the FXYD proteins, are controlled extensively during development and to accommodate physiological needs. The spatial and temporal expression of Na,K-ATPase is partially regulated at the transcriptional level. Numerous transcription factors, hormones, growth factors, lipids, and extracellular stimuli modulate the transcription of the Na,K-ATPase subunits. Moreover, epigenetic mechanisms also contribute to the regulation of Na,K-ATPase expression. With the ever growing knowledge about diseases associated with the malfunction of Na,K-ATPase, this review aims at summarizing the best-characterized transcription regulators that modulate Na,K-ATPase subunit levels. As abnormal expression of Na,K-ATPase subunits has been observed in many carcinoma, we will also discuss transcription factors that are associated with epithelial-mesenchymal transition, a crucial step in the progression of many tumors to malignant disease.
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Affiliation(s)
- Zhiqin Li
- Nemours Center for Childhood Cancer Research, Nemours/Alfred I. duPont Hospital for Children Wilmington, DE, USA
| | - Sigrid A Langhans
- Nemours Center for Childhood Cancer Research, Nemours/Alfred I. duPont Hospital for Children Wilmington, DE, USA
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17
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Zeino M, Brenk R, Gruber L, Zehl M, Urban E, Kopp B, Efferth T. Cytotoxicity of cardiotonic steroids in sensitive and multidrug-resistant leukemia cells and the link with Na(+)/K(+)-ATPase. J Steroid Biochem Mol Biol 2015; 150:97-111. [PMID: 25797029 DOI: 10.1016/j.jsbmb.2015.03.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 03/04/2015] [Accepted: 03/17/2015] [Indexed: 12/12/2022]
Abstract
Cardiotonic steroids have long been in clinical use for treatment of heart failure and are now emerging as promising agents in various diseases, especially cancer. Their main target is Na(+)/K(+)-ATPase, a membrane protein involved in cellular ion homeostasis. Na(+)/K(+)-ATPase has been implicated in cancer biology by affecting several cellular events and signaling pathways in both sensitive and drug-resistant cancer cells. Hence, we investigated the cytotoxic activities of 66 cardiotonic steroids and cardiotonic steroid derivatives in sensitive CCRF-CEM and multidrug-resistant CEM/ADR5000 leukemia cells. Data were then subjected to quantitative structure-activity relationship analysis (QSAR) and molecular docking into Na(+)/K(+)-ATPase, which both indicated a possible differential expression of the pump in the mentioned cell lines. This finding was confirmed by western blotting, intracellular potassium labeling and next generation sequencing which showed that Na(+)/K(+)-ATPase was less expressed in multidrug-resistant than in sensitive cells.
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Affiliation(s)
- Maen Zeino
- Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
| | - Ruth Brenk
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
| | - Lisa Gruber
- Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
| | - Martin Zehl
- Department of Pharmacognosy, University of Vienna, Althanstraße 14, 1090 Vienna, Austria; Department of Pharmaceutical Chemistry, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Ernst Urban
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Brigitte Kopp
- Department of Pharmacognosy, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Thomas Efferth
- Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany.
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18
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Wahren J, Larsson C. C-peptide: new findings and therapeutic possibilities. Diabetes Res Clin Pract 2015; 107:309-19. [PMID: 25648391 DOI: 10.1016/j.diabres.2015.01.016] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/15/2015] [Indexed: 12/18/2022]
Abstract
Much new information on C-peptide physiology has appeared during the past 20 years. It has been shown that C-peptide binds specifically to cell membranes, elicits intracellular signaling via G-protein and Ca2+ -dependent pathways, resulting in activation and increased expression of endothelial nitric oxide synthase, Na+, K+ -ATPase and several transcription factors of importance for anti-inflammatory, anti-oxidant and cell protective mechanisms. Studies in animal models of diabetes and early clinical trials in patients with type 1 diabetes demonstrate that C-peptide in replacement doses elicits beneficial effects on early stages of diabetes-induced functional and structural abnormalities of the peripheral nerves, the kidneys and the retina. Much remains to be learned about C-peptide's mechanism of action and long-term clinical trials in type 1 diabetes subjects will be required to determine C-peptide's clinical utility. Nevertheless, even a cautious evaluation of the available evidence presents the picture of a bioactive endogenous peptide with therapeutic potential.
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Affiliation(s)
- John Wahren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Cebix AB, Stockholm, Sweden.
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19
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Taubel J, Ferber G, Lorch U, Batchvarov V, Savelieva I, Camm AJ. Thorough QT study of the effect of oral moxifloxacin on QTc interval in the fed and fasted state in healthy Japanese and Caucasian subjects. Br J Clin Pharmacol 2015; 77:170-9. [PMID: 23713767 DOI: 10.1111/bcp.12168] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 04/21/2013] [Indexed: 11/28/2022] Open
Abstract
AIMS The aims of this study were three-fold and were to (i) investigate the effect of food (fasted and fed state) on the degree of QT prolongation caused by moxifloxacin under the rigorous conditions of a TQT study, (ii) differentiate the effects on QTc that arise from changes in PK from those arising as a result of electrophysiological changes attributable to raised levels of C-peptide [11] offsetting in part the IKr blocking properties of moxifloxacin and (iii) characterize the QTc F profile of oral moxifloxacin (400 mg) in healthy Japanese volunteers compared with Caucasian subjects. METHODS The study population consisted of 32 healthy non-smoking, Caucasian (n = 13) and Japanese (n = 19), male and female subjects, aged between 20-45 years with a body mass index of between 18 to 25 kg m(-2). Female volunteers were required to use an effective contraceptive method or be abstinent. Subjects with ECGs which were deemed unsuitable for evaluation in a TQT study were excluded. ECGs were recorded in triplicate with subsequent blinded manual adjudication of the automated interval measurements. Electrocardiograms in the placebo arm were recorded twice in fasted and fed condition. RESULTS The results demonstrated a substantial change in the typical moxifloxacin effect on the ECG. The effect on ΔΔQTc in the fed state led to a significant delay and a modest reduction compared with the fasted state correcting both conditions with the corresponding placebo data. The largest QTc F change from baseline in the fed state was observed at 4 h with a peak value of 11.6 ms (two-sided 90% CI 9.1, 14.1). In comparison, the largest QTc F change observed in the fasted state was 14.4 ms (90% CI 11.9, 16.8) and occurred at 2.5 h post-dose. The PK of moxifloxacin were altered by food and this change was consistent with the observed QTc F change. In the fed state plasma concentrations of moxifloxacin were considerably and consistently lower in comparison with the fasted state, and this applied to both ethnicities. The concentration-effect analysis revealed that there was no change in slope and confirmed that the difference in this analysis was caused by a change in the PK profile of moxifloxacin. Comparisons of the moxifloxacin effect in the fed state compared with fasted placebo also revealed a pharmacodynamic effect whereby a meal appears to antagonize the effects of moxifloxacin on the lengths of the QTc interval. CONCLUSIONS Our findings demonstrate that the food effect by itself leads to a shortening of the QTc interval offsetting in part the effects of a 400 mg single dose of oral moxifloxacin. The typical moxifloxacin PK profile is also altered by food prior to dosing reducing the Cmax and delays the peak effects on QTc up to several hours thereby reducing the overall magnitude of the effect and delaying the peak QTc prolongation. The contribution of the two effects was clearly discernible. Given that moxifloxacin is sometimes given with food in TQT studies, consideration should be given to adequate baseline corrections and appropriate sampling time points. In this study the PK-PD relationship was similar for Japanese and Caucasian subjects in the fed and fasted conditions, thereby providing further evidence that the sensitivity to the QTc prolonging effects of fluoroquinolones was likely to be independent of ethnicity. The small differences observed between the two subpopulations were not statistically significant. However, future studies should give consideration to formal ethnic comparisons as a secondary outcome parameter as very little is known about the relationship between ethnicity and drug effects on cardiac repolarization.
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20
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Zhao L, Ma J, Wang S, Xie Y. Relationship between β-cell function, metabolic control, and microvascular complications in type 2 diabetes mellitus. Diabetes Technol Ther 2015; 17:29-34. [PMID: 25574593 DOI: 10.1089/dia.2014.0214] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND This study investigated the relationship among β-cell function, metabolic control, and diabetic microvascular complications in patients with type 2 diabetes mellitus (T2DM). SUBJECTS AND METHODS In total, 885 patients with type 2 diabetes mellitus (DM) were recruited from January 2012 to January 2014 and grouped into three groups according to the area under the curve of C-peptide [AUC(C-pep)] during the 75-g oral glucose tolerance test. Logistic regression analyses were used to evaluate the association between C-peptide and microvascular complications. RESULTS The prevalence of diabetic microvascular complications decreased from the first to the third AUC(C-pep) tertile (P < 0.01 for all), whereas the rates of nonalcoholic fatty liver disease (NAFLD) was positively associated with AUC(C-pep) values. Patients with lower AUC(C-pep) tertile exhibited higher levels of glycosylated hemoglobin and high-density lipoprotein cholesterol and longer duration of DM; however, levels of triglycerides, fasting C-peptide, 2-h C-peptide, body mass index, and homeostasis model assessment of insulin resistance index were lower compared with the third tertile. Comparison among patients with a similar DM duration showed a higher level of AUC(C-pep) was inversely associated with prevalence of microvascular complications. The odds ratios for nephropathy, retinopathy, and neuropathy in the lowest versus the highest AUC(C-pep) tertile were 3.10 (95% confidence interval, 2.01-4.78), 2.83 (1.73-4.64), and 2.04 (1.37-3.04) after adjustment for confounding factors. CONCLUSIONS Higher AUC(C-pep) levels were associated with a decreased prevalence of microvascular complications and a good level of glycemic control, whereas higher endogenous insulin levels were linked to the components of metabolic syndrome and increased rates of NAFLD.
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Affiliation(s)
- Lihua Zhao
- Department of Diabetic Neurology, Hospital of Metabolic Disease, Tianjin Medical University , Tianjin, China
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21
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Richards JP, Bowles EA, Gordon WR, Ellsworth ML, Stephenson AH, Sprague RS. Mechanisms of C-peptide-mediated rescue of low O2-induced ATP release from erythrocytes of humans with type 2 diabetes. Am J Physiol Regul Integr Comp Physiol 2014; 308:R411-8. [PMID: 25552662 DOI: 10.1152/ajpregu.00420.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The circulating erythrocyte, by virtue of the regulated release of ATP in response to reduced oxygen (O2) tension, plays a key role in maintaining appropriate perfusion distribution to meet tissue needs. Erythrocytes from individuals with Type 2 diabetes (DM2) fail to release ATP in response to this stimulus. However, the administration of C-peptide and insulin at a 1:1 ratio was shown to restore this important physiological response in humans with DM2. To begin to investigate the mechanisms by which C-peptide influences low O2-induced ATP release, erythrocytes from healthy humans and humans with DM2 were exposed to reduced O2 in a thin-film tonometer, and ATP release under these conditions was compared with release during normoxia. We determined that 1) low O2-induced ATP release from DM2 erythrocytes is rescued by C-peptide in the presence and absence of insulin, 2) the signaling pathway activated by C-peptide in human erythrocytes involves PKC, as well as soluble guanylyl cyclase (sGC) and 3) inhibitors of cGMP degradation rescue low O2-induced ATP release from DM2 erythrocytes. These results provide support for the hypothesis that both PKC and sGC are components of a signaling pathway activated by C-peptide in human erythrocytes. In addition, since both C-peptide and phosphodiesterase 5 inhibitors rescue low O2-induced ATP release from erythrocytes of humans with DM2, their administration to humans with DM2 could aid in the treatment and/or prevention of the vascular disease associated with this condition.
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Affiliation(s)
- Jennifer P Richards
- Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, Missouri
| | - Elizabeth A Bowles
- Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, Missouri
| | - Weston R Gordon
- Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, Missouri
| | - Mary L Ellsworth
- Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, Missouri
| | - Alan H Stephenson
- Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, Missouri
| | - Randy S Sprague
- Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, Missouri
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22
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McKillop AM, Ng MT, Abdel-Wahab YHA, Flatt PR. Evidence for inhibitory autocrine effects of proinsulin C-peptide on pancreatic β-cell function and insulin secretion. Diabetes Obes Metab 2014; 16:937-46. [PMID: 24702738 DOI: 10.1111/dom.12300] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/28/2014] [Accepted: 03/31/2014] [Indexed: 12/21/2022]
Abstract
AIMS Autocrine and paracrine regulatory mechanisms ensure integrated secretion of islet hormones that respond efficiently to changes in metabolic need. As proinsulin C-peptide exerts various biological effects and binds to cell membranes including insulin-secreting β cells, its physiological role in insulin release was examined. METHODS Insulin releasing activity of human and rat C-peptides were studied in the clonal pancreatic cell line, BRIN-BD11, with findings substantiated using isolated islets and in vivo studies employing SWISS TO mice. RESULTS Acute exposure of clonal β cells to human C-peptide resulted in concentration-dependent inhibitory effects on insulin secretion at 5.6 mM (p < 0.05-p < 0.001) and 16.7 mM (p < 0.01-p < 0.001) glucose. At physiologically relevant intra-islet concentrations (10(-9) -10(-6) M), C-peptide suppressed the insulin-secretory responses to a range of secretagogues acting at different points in the β cell stimulus-secretion coupling pathway including alanine (p < 0.05), Ca(2+) (p < 0.001), arginine (p < 0.05), tolbutamide (p < 0.001), glucagon-like peptide 1 (GLP-1) (p < 0.001), isobutylmethylxanthine (IBMX) (p < 0.01) and KCl (p < 0.05). Similar results were obtained using isolated mouse pancreatic islets. Human C-peptide (3 × 10(-7) M, p < 0.001), somatostatin-14 (3 × 10(-7) M, p < 0.01) and diazoxide (300 µM, p < 0.001) reduced both alanine and glucose-stimulated insulin release by 43, 25 and 48%, respectively. The effects of human C-peptide were reproduced using rat C-peptide I and II. C-peptide also inhibited in vivo glucose-stimulated insulin release and impaired glucose tolerance in mice. CONCLUSIONS C-peptide is a biologically active endogenous peptide hormone that exerts inhibitory autocrine effects on pancreatic β-cell function. Mechanisms involving the activation of K(+) channels and a distal effect downstream of increased cytoplasmic Ca(2+) appear to be implicated in the inhibition of insulin secretion.
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Affiliation(s)
- A M McKillop
- SAAD Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, UK
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23
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24
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Luppi P, Kallas Å, Wahren J. Can C-peptide mediated anti-inflammatory effects retard the development of microvascular complications of type 1 diabetes? Diabetes Metab Res Rev 2013; 29:357-62. [PMID: 23463541 DOI: 10.1002/dmrr.2409] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 01/30/2013] [Accepted: 02/28/2013] [Indexed: 02/07/2023]
Abstract
Hyperglycemia is considered to be the major cause of microvascular complications of diabetes. Growing evidence highlights the importance of hyperglycemia-mediated inflammation in the initiation and progression of microvascular complications in type 1 diabetes. We hypothesize that lack of proinsulin C-peptide and lack of its anti-inflammatory properties contribute to the development of microvascular complications. Evidence gathered over the past 20 years shows that C-peptide is a biologically active peptide in its own right. It has been shown to reduce formation of reactive oxygen species and nuclear factor-κB activation induced by hyperglycemia, resulting in inhibition of cytokine, chemokine and cell adhesion molecule formation as well as reduced apoptotic activity. In addition, C-peptide stimulates and induces the expression of both Na⁺, K⁺-ATPase and endothelial nitric oxide synthase. Animal studies and small-scale clinical trials in type 1 diabetes patients suggest that C-peptide replacement combined with regular insulin therapy exerts beneficial effects on kidney and nerve dysfunction. Further clinical trials in patients with microvascular complications including measurements of inflammatory markers are warranted to explore the clinical significance of the aforementioned, previously unrecognized, C-peptide effects.
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Affiliation(s)
- Patrizia Luppi
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Rangos Research Center, Pittsburgh, PA 15201, USA
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25
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Banki NF, Ver A, Wagner LJ, Vannay A, Degrell P, Prokai A, Gellai R, Lenart L, Szakal DN, Kenesei E, Rosta K, Reusz G, Szabo AJ, Tulassay T, Baylis C, Fekete A. Aldosterone antagonists in monotherapy are protective against streptozotocin-induced diabetic nephropathy in rats. PLoS One 2012; 7:e39938. [PMID: 22761931 PMCID: PMC3386228 DOI: 10.1371/journal.pone.0039938] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 05/29/2012] [Indexed: 11/30/2022] Open
Abstract
Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) are the standard clinical therapy of diabetic nephropathy (DN), while aldosterone antagonists are only used as adjuncts. Previously in experimental DN we showed that Na/K ATPase (NKA) is mislocated and angiotensin II leads to superimposed renal progression. Here we investigated the monotherapeutic effect of aldosterone blockers on the progression of DN and renal NKA alteration in comparison to ACEi and ARBs. Streptozotocin-diabetic rats developing DN were treated with aldosterone antagonists; ACEi and ARB. Renal function, morphology, protein level and tubular localization of NKA were analyzed. To evaluate the effect of high glucose per se; HK-2 proximal tubular cells were cultured in normal or high concentration of glucose and treated with the same agents. Aldosterone antagonists were the most effective in ameliorating functional and structural kidney damage and they normalized diabetes induced bradycardia and weight loss. Aldosterone blockers also prevented hyperglycemia and diabetes induced increase in NKA protein level and enzyme mislocation. A monotherapy with aldosterone antagonists might be as, or more effective than ACEi or ARBs in the prevention of STZ-induced DN. Furthermore the alteration of the NKA could represent a novel pathophysiological feature of DN and might serve as an additional target of aldosterone blockers.
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Affiliation(s)
- Nora F. Banki
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
- SE-MTA “Lendulet” Diabetes Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Agota Ver
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Laszlo J. Wagner
- Department of Transplantation and Surgery, Semmelweis University, Budapest, Hungary
| | - Adam Vannay
- Research Laboratory for Pediatrics and Nephrology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Peter Degrell
- 2nd Department of Medicine and Nephrological Center, Pécs, Hungary
| | - Agnes Prokai
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Renata Gellai
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
- SE-MTA “Lendulet” Diabetes Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Lilla Lenart
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
- SE-MTA “Lendulet” Diabetes Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | | | - Eva Kenesei
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Klara Rosta
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Gyorgy Reusz
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Attila J. Szabo
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Tivadar Tulassay
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
- Research Laboratory for Pediatrics and Nephrology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Chris Baylis
- Departments of Physiology and Functional Genomics and Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Andrea Fekete
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
- SE-MTA “Lendulet” Diabetes Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
- * E-mail:
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26
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Affiliation(s)
- John Wahren
- Department of Molecular Medicine and Surgery, Karolinska Institutet,Stockholm, Sweden.
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