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Yildirim G, Bergamo ETP, Poudel SB, Ruff RR, Dixit M, Hu B, Mijares DQ, Witek L, Chlebek C, Harrison DE, Strong R, Miller RA, Ladiges W, Bromage TG, Rosen CJ, Yakar S. Long-term effects of canagliflozin treatment on the skeleton of aged UM-HET3 mice. GeroScience 2023; 45:1933-1951. [PMID: 37166526 PMCID: PMC10400751 DOI: 10.1007/s11357-023-00803-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 04/18/2023] [Indexed: 05/12/2023] Open
Abstract
Sodium glucose cotransporter-2 inhibitors (SGLT2is) promote urinary glucose excretion and decrease plasma glucose levels independent of insulin. Canagliflozin (CANA) is an SGLT2i, which is widely prescribed, to reduce cardiovascular complications, and as a second-line therapy after metformin in the treatment of type 2 diabetes mellitus. Despite the robust metabolic benefits, reductions in bone mineral density (BMD) and cortical fractures were reported for CANA-treated subjects. In collaboration with the National Institute on Aging (NIA)-sponsored Interventions Testing Program (ITP), we tested skeletal integrity of UM-HET3 mice fed control (137 mice) or CANA-containing diet (180 ppm, 156 mice) from 7 to 22 months of age. Micro-computed tomography (micro-CT) revealed that CANA treatment caused significant thinning of the femur mid-diaphyseal cortex in both male and female mice, did not affect trabecular bone architecture in the distal femur or the lumbar vertebra-5 in male mice, but was associated with thinning of the trabeculae at the distal femur in CANA-treated female mice. In male mice, CANA treatment is associated with significant reductions in cortical bone volumetric BMD by micro-CT, and by quantitative backscattered scanning electron microscopy. Raman microspectroscopy, taken at the femur mid-diaphyseal posterior cortex, showed significant reductions in the mineral/matrix ratio and an increased carbonate/phosphate ratio in CANA-treated male mice. These data were supported by thermogravimetric assay (TGA) showing significantly decreased mineral and increased carbonate content in CANA-treated male mice. Finally, the sintered remains of TGA were subjected to X-ray diffraction and showed significantly higher fraction of whitlockite, a calcium orthophosphate mineral, which has higher resorbability than hydroxyapatite. Overall, long-term CANA treatment compromised bone morphology and mineral composition of bones, which likely contribute to increased fracture risk seen with this drug.
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Affiliation(s)
- Gozde Yildirim
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Edmara T. P. Bergamo
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
| | - Sher Bahadur Poudel
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Ryan R. Ruff
- David B. Kriser Dental Center, Department of Epidemiology and Health Promotion, New York University College of Dentistry, New York, NY 10010-4086 USA
| | - Manisha Dixit
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Bin Hu
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Dindo Q. Mijares
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
| | - Lukasz Witek
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
- Department of Biomedical Engineering, Tandon School of Engineering New York University, Brooklyn, NY 11201 USA
| | - Carolyn Chlebek
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, USA
| | | | - Randy Strong
- Geriatric Research, Education and Clinical Center and Research Service, South Texas Veterans Health Care System, San Antonio, TX USA
- Barshop Institute for Longevity and Aging Studies and Department of Pharmacology, The University of Texas Health Science Center, San Antonio, TX USA
| | - Richard A. Miller
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, MI USA
| | - Warren Ladiges
- Department of Comparative Medicine, School of Medicine, University of Washington, Seattle, WA USA
| | - Timothy G. Bromage
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Clifford J. Rosen
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, USA
| | - Shoshana Yakar
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
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Chen Y, Wu X, Liu X, Lai J, Liu Y, Song M, Li F, Gong Q. Biochemical, transcriptomic and metabolomic responses to total dissolved gas supersaturation and their underlying molecular mechanisms in Yangtze sturgeon (Acipenser dabryanus). Environ Res 2023; 216:114457. [PMID: 36183788 DOI: 10.1016/j.envres.2022.114457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/08/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
With the rapid development of hydropower facility construction, the total dissolved gas (TDG) generated by dam discharge is seriously threatening the survival of fish and has become an ecological environmental issue of global concern. However, how TDG affects fish physiology and the underlying molecular mechanism remain poorly known. In this study, Acipenser dabryanus, an ancient living fossil that is a flagship species of the Yangtze River, was exposed to water supersaturated with TDG at a level of 116% for 48 h. A comprehensive analysis was performed to study the effect of TDG supersaturation stress on A. dabryanus, including histopathological, biochemical, transcriptomic and metabolomic analyses. The histopathological results showed that mucosal-associated lymphoid tissues were seriously damaged after TDG supersaturation stress. Plasma catalase levels increased significantly under TDG supersaturation stress, while superoxide dismutase levels decreased significantly. Transcriptomic analysis revealed 289 upregulated genes and 162 downregulated genes in gill tissue and 535 upregulated and 104 downregulated genes in liver tissue. Metabolomic analysis revealed 63 and 164 differentially abundant metabolites between the control group and TDG group in gill and liver, respectively. The majority of heat shock proteins and genes related to ubiquitin and various immune-related pathways were significantly upregulated by TDG supersaturation stress. Integrated transcriptomic and metabolomic analyses revealed the upregulation of amino acid metabolism and glycometabolism pathways under TDG supersaturation stress. Glycerophospholipid metabolism was increased which might be associated with maintaining cell membrane integrity. This is the first study revealing the underlying molecular mechanisms of effects of TDG supersaturation on fish. Our results suggested that acute TDG supersaturation stress could enhance immune and antioxidative functions and activate energy metabolic pathways as an adaptive mechanism in A. dabryanus.
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Affiliation(s)
- Yeyu Chen
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Xiaoyun Wu
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Xiaoqing Liu
- Key Laboratory of Fluid and Power Machinery, Ministry of Education, Xihua University, Chengdu, 610039, China
| | - Jiansheng Lai
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Ya Liu
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Mingjiang Song
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Feiyang Li
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Quan Gong
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China.
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Nakano D, Akiba J, Tsutsumi T, Kawaguchi M, Yoshida T, Koga H, Kawaguchi T. Hepatic expression of sodium-glucose cotransporter 2 (SGLT2) in patients with chronic liver disease. Med Mol Morphol 2022; 55:304-315. [PMID: 36131166 PMCID: PMC9606064 DOI: 10.1007/s00795-022-00334-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/24/2022] [Indexed: 11/04/2022]
Abstract
Sodium–glucose cotransporter 2 (SGLT2) occurs in the proximal renal tubule cells. We investigate the hepatic expression of SGLT2 and its related factors in patients with chronic liver disease. This is a retrospective human study. The liver tissues were biopsied from patients with chronic liver disease (n = 30). The expression levels of SGLT2 were evaluated by immunostaining. Furthermore, the undirected graphical model was used to identify factors associated with hepatic expression levels of SGLT2. The SGLT2 expression was observed in not only the kidney, but also the liver in immunostaining (SGLT2 intensity: kidney 165.8 ± 15.6, liver 114.4 ± 49.0 arbitrary units, P < 0.01) and immunoblotting. There was no significant difference in hepatic expression of SGLT2 in the stratified analysis according to age, sex, BMI, and the severity of the liver disease. In the undirected graphical model, SGLT2 directly interacted with various factors such as sex, fatty change, neutrophil-to-lymphocyte ratio, triglyceride, hemoglobin A1c, creatinine, and albumin (partial correlation coefficient 0.4–0.6 for sex and 0.2–0.4 for others). The expression of SGLT2 was observed in the hepatocytes of patients with chronic liver disease. The undirected graphical model demonstrated the complex interaction of hepatic expression levels of SGLT2 with gender, inflammation, renal function, and lipid/glucose/protein metabolisms.
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Affiliation(s)
- Dan Nakano
- Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi Kurume, Kurume, 830-0011, Japan.
| | - Jun Akiba
- Department of Pathology, Kurume University Hospital, Kurume, Japan
| | - Tsubasa Tsutsumi
- Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi Kurume, Kurume, 830-0011, Japan
| | - Machiko Kawaguchi
- Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi Kurume, Kurume, 830-0011, Japan
| | - Takafumi Yoshida
- Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi Kurume, Kurume, 830-0011, Japan
| | - Hironori Koga
- Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi Kurume, Kurume, 830-0011, Japan.,Liver Cancer Division, Research Center for Innovative Cancer Therapy, Kurume University, Kurume, Japan
| | - Takumi Kawaguchi
- Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi Kurume, Kurume, 830-0011, Japan.,Liver Cancer Division, Research Center for Innovative Cancer Therapy, Kurume University, Kurume, Japan
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Erdoğan A, Bozkurt A, altun A, Turan A. Can we contribute to the diagnosis of diabetes and regulation of blood glucose by increasing the urologists’ awareness of glucosuria? Urologia 2020; 87:209-213. [DOI: 10.1177/0391560320919593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aims: Diabetes mellitus is a progressive, chronic, systemic, metabolic disease that must be managed effectively. Its prevalence is increasing rapidly. We investigated whether urologists’ awareness and recognition of glucosuria contributed to the diagnosis of diabetes and regulation of blood glucose. Methods: A total of 39,053 patients were retrospectively evaluated between January 2018 and February 2019. Of them, 16,211 had undergone urinalysis for varied reasons. Glucosuria was semi-quantitatively measured as (+), (++), (+++), and (++++). Patients were assessed in terms of whether they had been referred to endocrinology or internal medicine departments within the 15 days and the presence/absence of a previous or new diagnosis of diabetes mellitus by measuring blood glucose and HgbA1c levels. Results: Glucosuria was detected in 665 patients (4.1%), of whom 495 were included in the study. 417 (84.2%) had been previously diagnosed with diabetes mellitus, and 56 (11.3%) newly received a diabetes mellitus diagnosis. Blood glucose and HbA1c values were normal in 22 (4.4%) patients with glucosuria. HgbA1c value was determined as 7 or above in 381 (91.3%) of 417 cases with a previous diabetes mellitus diagnosis. Conclusion: Referring all patients detected to have glucosuria in the spot urine test at any time regardless of fasting/non-fasting to the relevant departments can contribute to the diagnosis and treatment of diabetes mellitus disease.
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Affiliation(s)
- Abdullah Erdoğan
- Department of Urology, Faculty of Medicine, Erzincan Binali Yildirim University, Erzincan, Turkey
| | - Aliseydi Bozkurt
- Department of Urology, Faculty of Medicine, Erzincan Binali Yildirim University, Erzincan, Turkey
| | - Abdulsemet altun
- Department of Urology, Faculty of Medicine, Erzincan Binali Yildirim University, Erzincan, Turkey
| | - Abdullah Turan
- Department of Urology, Faculty of Medicine, Erzincan Binali Yildirim University, Erzincan, Turkey
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Thrailkill KM, Bunn RC, Uppuganti S, Ray P, Garrett K, Popescu I, Pennings JS, Fowlkes JL, Nyman JS. Genetic ablation of SGLT2 function in mice impairs tissue mineral density but does not affect fracture resistance of bone. Bone 2020; 133:115254. [PMID: 31991250 PMCID: PMC7059549 DOI: 10.1016/j.bone.2020.115254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/22/2020] [Accepted: 01/24/2020] [Indexed: 01/14/2023]
Abstract
Selective sodium-dependent glucose co-transporter 2 inhibitors (SGLT2Is) are oral hypoglycemic medications utilized increasingly in the medical management of hyperglycemia among persons with type 2 diabetes (T2D). Despite favorable effects on cardiovascular events, specific SGLT2Is have been associated with an increased risk for atypical fracture and amputation in subgroups of the T2D population, a population that already has a higher risk for typical fragility fractures than the general population. To better understand the effect of SGLT2 blockade on skeletal integrity, independent of diabetes and its co-morbidities, we utilized the "Jimbee" mouse model of slc5a2 gene mutation to investigate the impact of lifelong SGLT2 loss-of-function on metabolic and skeletal phenotype. Jimbee mice maintained normal glucose homeostasis, but exhibited chronic polyuria, glucosuria and hypercalciuria. The Jimbee mutation negatively impacted appendicular growth of the femur and resulted in lower tissue mineral density of both cortical and trabecular bone of the femur mid-shaft and distal femur metaphysis, respectively. Several components of the Jimbee phenotype were characteristic only of male mice compared with female mice, including reductions: in body weight; in cortical area of the mid-shaft; and in trabecular thickness within the metaphysis. Despite these decrements, the strength of femur diaphysis in bending (cortical bone), which increased with age, and the strength of L6 vertebra in compression (primarily trabecular bone), which decreased with age, were not affected by the mutation. Moreover, the age-related decline in bone toughness was less for Jimbee mice, compared with control mice, such that by 49-50 weeks of age, Jimbee mice had significantly tougher femurs in bending than C57BL/6J mice. These results suggest that chronic blockade of SGLT2 in this model reduces the mineralization of bone but does not reduce its fracture resistance.
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Affiliation(s)
- Kathryn M Thrailkill
- University of Kentucky Barnstable Brown Diabetes Center and the Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America.
| | - R Clay Bunn
- University of Kentucky Barnstable Brown Diabetes Center and the Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America
| | - Sasidhar Uppuganti
- Department of Orthopaedic Surgery and the Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America; VA Tennessee Valley HealthCare System, Nashville, TN 37217, United States of America
| | - Philip Ray
- University of Kentucky Barnstable Brown Diabetes Center and the Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America
| | - Kate Garrett
- Department of Orthopaedic Surgery and the Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America; VA Tennessee Valley HealthCare System, Nashville, TN 37217, United States of America
| | - Iuliana Popescu
- University of Kentucky Barnstable Brown Diabetes Center and the Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America
| | - Jacquelyn S Pennings
- Department of Orthopaedic Surgery and the Center for Musculoskeletal Research, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America
| | - John L Fowlkes
- University of Kentucky Barnstable Brown Diabetes Center and the Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America
| | - Jeffry S Nyman
- Department of Orthopaedic Surgery and the Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America; VA Tennessee Valley HealthCare System, Nashville, TN 37217, United States of America
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Osaki A, Okada S, Saito T, Yamada E, Ono K, Niijima Y, Hoshi H, Yamada M. Renal threshold for glucose reabsorption predicts diabetes improvement by sodium-glucose cotransporter 2 inhibitor therapy. J Diabetes Investig 2016; 7:751-4. [PMID: 27181936 PMCID: PMC5009138 DOI: 10.1111/jdi.12473] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/17/2015] [Accepted: 01/03/2016] [Indexed: 11/28/2022] Open
Abstract
In the present study we examined the efficacy of sodium‐glucose cotransporter 2 inhibitors on improvement of glycated hemoglobin (HbA1c) in comparison with the renal threshold for glucose reabsorption in patients with type 2 diabetes mellitus. Patients visited the hospital once a month for a regular follow‐up examination with the determination of blood glucose and HbA1c levels, and urinary glucose concentration from spot urine samples. Patient samples were compared before and after ipragliflozin administration. We defined the renal threshold for glucose reabsorption as the lowest blood glucose level that correlated with the first detectable appearance of urine glucose. These data showed a significant negative correlation between improvement of HbA1c level and renal threshold for glucose reabsorption in patients treated with the sodium‐glucose cotransporter 2 inhibitor. These findings show that patients who have a higher renal threshold for glucose reabsorption can be expected to more effectively respond to sodium‐glucose cotransporter 2 inhibitor therapy in terms of lowering HbA1c levels.
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Affiliation(s)
- Aya Osaki
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Shuichi Okada
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Tsugumichi Saito
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Eijiro Yamada
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | | | | | | | - Masanobu Yamada
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan
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Laporta J, Hernandez LL. Serotonin receptor expression is dynamic in the liver during the transition period in Holstein dairy cows. Domest Anim Endocrinol 2015; 51:65-73. [PMID: 25528206 DOI: 10.1016/j.domaniend.2014.11.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 11/18/2014] [Accepted: 11/18/2014] [Indexed: 01/04/2023]
Abstract
Nonneuronal serotonin (5-HT) participates in glucose metabolism, but little is known regarding the actions of 5-HT in the liver during the transition period in dairy cattle. Here, we explore circulating patterns of 5-HT and characterize the hepatic 5-HT receptor and glucose transporter profiles around calving in multiparous Holstein dairy cows (n = 6, average lactation = 4 ± 1.9). Concentrations of serum 5-HT decreased on day -3 compared with -5 and -7 precalving (167.7 ± 80 vs 1511.1 ± 602 ng/mL). 5-HT nadir was on day -1 precalving and remained low postcalving (481.4 ± 49 ng/mL). Plasma glucose concentrations decreased precalving (P = 0.008) and were positively correlated with 5-HT during the precalving period (r = 0.55, P = 0.043). On day 1, postcalving hepatic messenger RNA expression of 5-HT1D, 2B, 3C, 6, and 7 receptors were decreased compared with day -7 (P < 0.048). The 5-HT3A and 5-HT3B decreased on day 7. The 5-HT2A increased on days 1 and 7 compared with -7 (P < 0.05). The 5-HT1F and 5-HT1A receptors were increased 2.5- and 3.8-fold on day 7, respectively, compared with days -7 and 1 (P < 0.046). The 5-HT5A was not detected, and 5-HT4 was detected on days -7 and 1 only. Expression of Glut-2,-5 and SGLT1 were decreased on days 1 and 7 compared with -7 (P < 0.05), whereas Glut-1 was increased on day 7 compared with -7 (P < 0.05). These results indicate that 5-HT could be important for liver glucose homeostasis possibly through receptor mediated signaling at specific times. Additional research is needed to further explore the functional role of these receptors in the liver during the transition from pregnancy to lactation.
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Affiliation(s)
- J Laporta
- Department of Dairy Science, University of Wisconsin, Madison, WI 53706, USA
| | - L L Hernandez
- Department of Dairy Science, University of Wisconsin, Madison, WI 53706, USA.
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Abstract
Dapagliflozin is a SGLT2 (Sodium/Glucose cotransporter 2) inhibitor that reduces circulating glucose levels in type 2 diabetic patients by blocking the SGLT2-dependent reabsorption of glucose in the kidney. Dapagliflozin is metabolized by UGT1A9 (UDP Glucuronosyltransferase 1 family, Polypeptidase A9), suppressing its SGLT2 inhibitor activity. However little information is available on whether dapagliflozin acts in the absence of dapagliflozin metabolism. Treatment with 0.5μM dapagliflozin significantly reduced the number of HCT116 cells, which express SGLT2 but not UGT1A9. This was independent of SGLT2 inhibition, as the SGLT2 inhibitor phlorizin had no effect. Dapagliflozin also enhanced Erk phosphorylation but without changing levels of uncleaved and cleaved PPAR and uncleaved caspase-3, suggesting that the cause of the decrease in HCT116 cell number was apoptosis independent cell death. Taken together, these data indicate a new potential role for dapagliflozin as an anticancer reagent in tumor cell populations that do not express UGT1A9.
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Affiliation(s)
- Tsugumichi Saito
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma 371-8511, Japan
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Abstract
Glucose is the major precursor of lactose, which is synthesized in Golgi vesicles of mammary secretory alveolar epithelial cells during lactation. Glucose is taken up by mammary epithelial cells through a passive, facilitative process, which is driven by the downward glucose concentration gradient across the plasma membrane. This process is mediated by facilitative glucose transporters (GLUTs), of which there are 14 known isoforms. Mammary glands mainly express GLUT1 and GLUT8, and GLUT1 is the predominant isoform with a Km of ~10 mM and transport activity for mannose and galactose in addition to glucose. Mammary glucose transport activity increases dramatically from the virgin state to the lactation state, with a concomitant increase in GLUT expression. The increased GLUT expression during lactogenesis is not stimulated by the accepted lactogenic hormones. New evidence indicates that a possible low oxygen tension resulting from increased metabolic rate and oxygen consumption may play a major role in stimulating glucose uptake and GLUT1 expression in mammary epithelial cells during lactogenesis. In addition to its primary presence on the plasma membrane, GLUT1 is also expressed on the Golgi membrane of mammary epithelial cells and is likely involved in facilitating the uptake of glucose and galactose to the site of lactose synthesis. Because lactose synthesis dictates milk volume, regulation of GLUT expression and trafficking represents potentially fruitful areas for further research in dairy production. In addition, this research will have pathological implications for the treatment of breast cancer because glucose uptake and GLUT expression are up-regulated in breast cancer cells to accommodate the increased glucose need.
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Affiliation(s)
- Feng-Qi Zhao
- Laboratory of Lactation and Metabolic Physiology, Department of Animal Science, University of Vermont, 211 Terrill Building, 570 Main Street, Burlington, VT, 05405, USA,
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Sabolic I, Vrhovac I, Eror DB, Gerasimova M, Rose M, Breljak D, Ljubojevic M, Brzica H, Sebastiani A, Thal SC, Sauvant C, Kipp H, Vallon V, Koepsell H. Expression of Na+-D-glucose cotransporter SGLT2 in rodents is kidney-specific and exhibits sex and species differences. Am J Physiol Cell Physiol 2012; 302:C1174-88. [PMID: 22262063 DOI: 10.1152/ajpcell.00450.2011] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
With a novel antibody against the rat Na(+)-D-glucose cotransporter SGLT2 (rSGLT2-Ab), which does not cross-react with rSGLT1 or rSGLT3, the ∼75-kDa rSGLT2 protein was localized to the brush-border membrane (BBM) of the renal proximal tubule S1 and S2 segments (S1 > S2) with female-dominant expression in adult rats, whereas rSglt2 mRNA expression was similar in both sexes. Castration of adult males increased the abundance of rSGLT2 protein; this increase was further enhanced by estradiol and prevented by testosterone treatment. In the renal BBM vesicles, the rSGLT1-independent uptake of [(14)C]-α-methyl-D-glucopyranoside was similar in females and males, suggesting functional contribution of another Na(+)-D-glucose cotransporter to glucose reabsorption. Since immunoreactivity of rSGLT2-Ab could not be detected with certainty in rat extrarenal organs, the SGLT2 protein was immunocharacterized with the same antibody in wild-type (WT) mice, with SGLT2-deficient (Sglt2 knockout) mice as negative control. In WT mice, renal localization of mSGLT2 protein was similar to that in rats, whereas in extrarenal organs neither mSGLT2 protein nor mSglt2 mRNA expression was detected. At variance to the findings in rats, the abundance of mSGLT2 protein in the mouse kidneys was male dominant, whereas the expression of mSglt2 mRNA was female dominant. Our results indicate that in rodents the expression of SGLT2 is kidney-specific and point to distinct sex and species differences in SGLT2 protein expression that cannot be explained by differences in mRNA.
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Affiliation(s)
- Ivan Sabolic
- Molecular Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Croatia.
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Zhao FQ, Keating AF. Functional properties and genomics of glucose transporters. Curr Genomics 2011; 8:113-28. [PMID: 18660845 DOI: 10.2174/138920207780368187] [Citation(s) in RCA: 363] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 12/08/2006] [Accepted: 12/17/2007] [Indexed: 12/17/2022] Open
Abstract
Glucose is the major energy source for mammalian cells as well as an important substrate for protein and lipid synthesis. Mammalian cells take up glucose from extracellular fluid into the cell through two families of structurallyrelated glucose transporters. The facilitative glucose transporter family (solute carriers SLC2A, protein symbol GLUT) mediates a bidirectional and energy-independent process of glucose transport in most tissues and cells, while the NaM(+)/glucose cotransporter family (solute carriers SLC5A, protein symbol SGLT) mediates an active, Na(+)-linked transport process against an electrochemical gradient. The GLUT family consists of thirteen members (GLUT1-12 and HMIT). Phylogenetically, the members of the GLUT family are split into three classes based on protein similarities. Up to now, at least six members of the SGLT family have been cloned (SGLT1-6). In this review, we report both the genomic structure and function of each transporter as well as intra-species comparative genomic analysis of some of these transporters. The affinity for glucose and transport kinetics of each transporter differs and ranges from 0.2 to 17mM. The ability of each protein to transport alternative substrates also differs and includes substrates such as fructose and galactose. In addition, the tissue distribution pattern varies between species. There are different regulation mechanisms of these transporters. Characterization of transcriptional control of some of the gene promoters has been investigated and alternative promoter usage to generate different protein isoforms has been demonstrated. We also introduce some pathophysiological roles of these transporters in human.
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Affiliation(s)
- Feng-Qi Zhao
- Lactation and Mammary Gland Biology Group, Department of Animal Science, University of Vermont, Burlington, VT, USA
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Aschenbach JR, Steglich K, Gäbel G, Honscha KU. Expression of mRNA for glucose transport proteins in jejunum, liver, kidney and skeletal muscle of pigs. J Physiol Biochem 2010; 65:251-66. [PMID: 20119820 DOI: 10.1007/bf03180578] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Indexed: 01/12/2023]
Abstract
Although pigs are adapted to starch-rich diets and have high turnover rates of glucose, very scarce information is available on the molecular basis of glucose transport. Therefore, the present study attempted a systematic screening for the presence of mRNA of glucose transport proteins in main organs of glucose absorption, production and conservation. From the members of the solute carrier family SLC5A (sodium glucose cotransporter), the porcine jejunum was positive for SGLT1 and SGLT3, but also contained detectable levels of SGLT5. Liver contained SGLT1, SGLT5, traces of SGLT3 and, in one of five pigs, SGLT2. Kidney contained SGLT1, SGLT2, SGLT3, SGLT5 and hardly detectable levels of SGLT4. Skeletal muscle showed weak signals for SGLT3 and SGLT5. Screening for members of the SLC2A family (facilitated glucose transporter) in intestine revealed the presence of mRNA for GLUT1, GLUT2, GLUT5, GLUT7 and GLUT8, while GLUT3, GLUT4, GLUT10 and GLUT11 were also detectable. The liver contained GLUT1, GLUT2 and GLUT8 mRNA, while GLUT3, GLUT4, GLUT5, GLUT10 and GLUT11 were poorly detectable. The kidney was positive for GLUT1, GLUT2, GLUT5, GLUT8 and GLUT11, but traces of GLUT3, GLUT4 and GLUT10 could also be detected. Skeletal muscle had the strongest signal for GLUT4, while GLUT1, GLUT3, GLUT5, GLUT8, GLUT10 and GLUT11 showed weak signals. A total of 12 unique partial cDNA sequences were submitted to GenBank. In conclusion, this study provides molecular insight into the organ-specific expression of glucose transporters in pigs and thus sheds light on the way of glucose handling in this omnivorous species.
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Affiliation(s)
- J R Aschenbach
- Institute of Veterinary Physiology, University of Leipzig, An den Tierkliniken 7, D-04103 Leipzig, Germany.
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Abstract
Glucose is the primary precursor for the synthesis of lactose, which controls milk volume by maintaining the osmolarity of milk. Glucose uptake in the mammary gland plays a key role in milk production. Glucose transport across the plasma membranes of mammalian cells is carried out by 2 distinct processes: facilitative transport, mediated by a family of facilitative glucose transporters (GLUT); and sodium-dependent transport, mediated by the Na+/glucose cotransporters (SGLT). Transport kinetic studies indicate that glucose transport across the plasma membrane of the lactating bovine mammary epithelial cell has a K(m) value of 8.29 mM for 3-O-methyl-D-glucose and can be inhibited by both cytochalasin-B and phloretin, indicating a facilitative transport process. This is consistent with the observation that in the lactating bovine mammary gland, GLUT1 is the predominant glucose transporter. However, the bovine lactating mammary gland also expresses GLUT3, GLUT4, GLUT5, GLUT8, GLUT12, and sodium-dependent SGLT1 and SGLT2 at different levels. Studies of protein expression and cellular and subcellular localizations of these transporters are needed to address their physiological functions in the mammary gland. From late pregnancy to early lactation, expression of GLUT1, GLUT8, GLUT12, SGLT1, and SGLT2 mRNA increases from at least 5-fold to several hundred-fold, suggesting that these transporters may be regulated by lactogenic hormones and have roles in milk synthesis. The GLUT1 protein is detected in lactating mammary epithelial cells. Its expression level decreases from early to late lactation stages and becomes barely detectable in the nonlactating gland. Both GLUT1 mRNA and protein levels in the lactating mammary gland are not significantly affected by exogenous bovine growth hormone, and, in addition, GLUT1 mRNA does not appear to be affected by leptin.
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Affiliation(s)
- F-Q Zhao
- Lactation and Mammary Gland Biology Group, Department of Animal Science, University of Vermont, Burlington 05405, USA.
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Nagata K, Hata Y. Substrate specificity of a chimera made from Xenopus SGLT1-like protein and rabbit SGLT1. Biochim Biophys Acta 2006; 1758:747-54. [PMID: 16792998 DOI: 10.1016/j.bbamem.2006.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Revised: 05/02/2006] [Accepted: 05/04/2006] [Indexed: 10/24/2022]
Abstract
To characterize the sugar translocation pathway of Na(+)/glucose cotransporter type 1 (SGLT1), a chimera was made by substituting the extracellular loop between transmembrane domain (TM) 12 and TM13 of Xenopus SGLT1-like protein (xSGLT1L) with the homologous region of rabbit SGLT1. The chimera was expressed in Xenopus oocytes and its transport activity was measured by the two-microelectrode voltage-clamp method. The substrate specificity of the chimera was different from those of xSGLT1L and SGLT1. In addition the chimera's apparent Michaelis-Menten constant (K(m)) for myo-inositol, 0.06 mM, was about one fourth of that of xSGLT1L, 0.25 mM, while the chimera's apparent K(m) for d-glucose, 0.8 mM, was about one eighth of that of xSGLT1L, 6.3 mM. Our results suggest that the extracellular loop between TM12 and TM13 participates in the sugar transport of SGLT1.
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Affiliation(s)
- Katsumi Nagata
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, Nishimachi 86, Yonago 683-8503, Japan.
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