TY - JOUR A1 - Jurowich, Christian Ferdinand A1 - Otto, Christoph A1 - Rikkala, Prashanth Reddy A1 - Wagner, Nicole A1 - Vrhovac, Ivana A1 - Sabolić, Ivan A1 - Germer, Christoph-Thomas A1 - Koepsell, Hermann T1 - Ileal interposition in rats with experimental type 2 like diabetes improves glycemic control independently of glucose absorption JF - Journal of Diabetes Research N2 - Bariatric operations in obese patients with type 2 diabetes often improve diabetes before weight loss is observed. In patients mainly Roux-en-Y-gastric bypass with partial stomach resection is performed. Duodenojejunal bypass (DJB) and ileal interposition (IIP) are employed in animal experiments. Due to increased glucose exposition of L-cells located in distal ileum, all bariatric surgery procedures lead to higher secretion of antidiabetic glucagon like peptide-1 (GLP-1) after glucose gavage. After DJB also downregulation of Na\(^{+}\)-D-glucose cotransporter SGLT1 was observed. This suggested a direct contribution of decreased glucose absorption to the antidiabetic effect of bariatric surgery. To investigate whether glucose absorption is also decreased after IIP, we induced diabetes with decreased glucose tolerance and insulin sensitivity in male rats and investigated effects of IIP on diabetes and SGLT1. After IIP, we observed weight-independent improvement of glucose tolerance, increased insulin sensitivity, and increased plasma GLP-1 after glucose gavage. The interposed ileum was increased in diameter and showed increased length of villi, hyperplasia of the epithelial layer, and increased number of L-cells. The amount of SGLT1-mediated glucose uptake in interposed ileum was increased 2-fold reaching the same level as in jejunum. Thus, improvement of glycemic control by bariatric surgery does not require decreased glucose absorption. KW - glucagon like peptide-1 KW - food intake KW - body weight KW - cotransporter SGLT1 KW - bariatric surgery KW - biliopancreatic diversion KW - intestinal glucose KW - gut hormones KW - duodenal jejunal bypass KW - Y-gastric bypass Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149166 VL - 2015 IS - 490365 ER - TY - JOUR A1 - Otto, Christoph A1 - Friedrich, Alexandra A1 - Madunić, Ivana Vrhovac A1 - Baumeier, Christian A1 - Schwenk, Robert W. A1 - Karaica, Dean A1 - Germer, Christoph-Thomas A1 - Schürmann, Annette A1 - Sabolić, Ivan A1 - Koepsell, Hermann, Hermann T1 - Antidiabetic Effects of a Tripeptide That Decreases Abundance of Na\(^+\)-D-glucose Cotransporter SGLT1 in the Brush-Border Membrane of the Small Intestine JF - ACS Omega N2 - In enterocytes, protein RS1 (RSC1A1) mediates an increase of glucose absorption after ingestion of glucose-rich food via upregulation of Na+-D-glucose cotransporter SGLT1 in the brush-border membrane (BBM). Whereas RS1 decelerates the exocytotic pathway of vesicles containing SGLT1 at low glucose levels between meals, RS1-mediated deceleration is relieved after ingestion of glucose-rich food. Regulation of SGLT1 is mediated by RS1 domain RS1-Reg, in which Gln-Ser-Pro (QSP) is effective. In contrast to QSP and RS1-Reg, Gln-Glu-Pro (QEP) and RS1-Reg with a serine to glutamate exchange in the QSP motif downregulate the abundance of SGLT1 in the BBM at high intracellular glucose concentrations by about 50%. We investigated whether oral application of QEP improves diabetes in db/db mice and affects the induction of diabetes in New Zealand obese (NZO) mice under glucolipotoxic conditions. After 6-day administration of drinking water containing 5 mM QEP to db/db mice, fasting glucose was decreased, increase of blood glucose in the oral glucose tolerance test was blunted, and insulin sensitivity was increased. When QEP was added for several days to a high fat/high carbohydrate diet that induced diabetes in NZO mice, the increase of random plasma glucose was prevented, accompanied by lower plasma insulin levels. QEP is considered a lead compound for development of new antidiabetic drugs with more rapid cellular uptake. In contrast to SGLT1 inhibitors, QEP-based drugs may be applied in combination with insulin for the treatment of type 1 and type 2 diabetes, decreasing the required insulin amount, and thereby may reduce the risk of hypoglycemia. KW - chemistry Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230654 N1 - Lizenz: https://pubs.acs.org/page/policy/authorchoice_termsofuse.html VL - 5 IS - 45 ER - TY - JOUR A1 - Bhavsar, Shefalee K. A1 - Singh, Yogesh A1 - Sharma, Piyush A1 - Khairnar, Vishal A1 - Hosseinzadeh, Zohreh A1 - Zhang, Shaqiu A1 - Palmada, Monica A1 - Sabolic, Ivan A1 - Koepsell, Hermann A1 - Lang, Karl S. A1 - Lang, Philipp A. A1 - Lang, Florian T1 - Expression of JAK3 Sensitive Na\(^+\) Coupled Glucose Carrier SGLT1 in Activated Cytotoxic T Lymphocytes JF - Cellular Physiology and Biochemistry N2 - Background: Similar to tumor cells, activated T-lymphocytes generate ATP mainly by glycolytic degradation of glucose. Lymphocyte glucose uptake involves non-concentrative glucose carriers of the GLUT family. In contrast to GLUT isoforms, Na+-coupled glucose-carrier SGLT1 accumulates glucose against glucose gradients and is effective at low extracellular glucose concentrations. The present study explored expression and regulation of SGLT1 in activated murine splenic cytotoxic T cells (CTLs) and human Jurkat T cells. Methods: FACS analysis, immunofluorescence, confocal microscopy, chemiluminescence and Western blotting were employed to estimate SGLT1 expression, function and regulation in lymphocytes, as well as dual electrode voltage clamp in SGLT1 ± JAK3 expressing Xenopus oocytes to quantify the effect of janus kinase3 (JAK3) on SGLT1 function. Results: SGLT1 is expressed in murine CTLs and also in human Jurkat T cells. 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose uptake was significantly decreased by SGLT1-blocker phloridzin (0.2 mM) and by pharmacological inhibition of JAK3 with WHI-P131 (156 µM), WHI-P154 (11.2 µM) and JAK3 inhibitor VI (0.5 µM). Electrogenic glucose transport (Iglucose) in Xenopus oocytes expressing human SGLT1 was increased by additional expression of human wild type JAK3, active A568VJAK3 but not inactive K851AJAK3. Coexpression of JAK3 enhanced the maximal transport rate without significantly modifying affinity of the carrier. Iglucose in SGLT1+JAK3 expressing oocytes was significantly decreased by WHI-P154 (11.2 µM). JAK3 increased the SGLT1 protein abundance in the cell membrane. Inhibition of carrier insertion by brefeldin A (5 µM) in SGLT1+JAK3 expressing oocytes resulted in a decline of Iglucose, which was similar in presence and absence of JAK3. Conclusions: SGLT1 is expressed in murine cytotoxic T cells and human Jurkat T cells and significantly contributes to glucose uptake in those cells post activation. JAK3 up-regulates SGLT1 activity by increasing the carrier protein abundance in the cell membrane, an effect enforcing cellular glucose uptake into activated lymphocytes and thus contributing to the immune response. KW - tumor cell KW - Cytotoxic T lymphocytes KW - Glucose uptake KW - Jurkat T cells KW - Energy depletion KW - Janus kinase Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164900 VL - 39 IS - 3 ER - TY - JOUR A1 - Salker, Madhuri S. A1 - Singh, Yogesh A1 - Zeng, Ni A1 - Chen, Hong A1 - Zhang, Shaqiu A1 - Umbach, Anja T. A1 - Fakhri, Hajar A1 - Kohlhofer, Ursula A1 - Quintanilla-Martinez, Leticia A1 - Durairaj, Ruban R. Peter A1 - Barros, Flavio S. V. A1 - Vrljicak, Pavle A1 - Ott, Sascha A1 - Brucker, Sara Y. A1 - Wallwiener, Diethelm A1 - Madunić, Ivana Vrhovac A1 - Breljak, Davorka A1 - Sabolić, Ivan A1 - Koepsell, Hermann A1 - Brosens, Jan J. A1 - Lang, Florian T1 - Loss of endometrial sodium glucose cotransporter SGLT1 is detrimental to embryo survival and fetal growth in pregnancy JF - Scientific Reports N2 - Embryo implantation requires a hospitable uterine environment. A key metabolic change that occurs during the peri-implantation period, and throughout early pregnancy, is the rise in endometrial glycogen content. Glycogen accumulation requires prior cellular uptake of glucose. Here we show that both human and murine endometrial epithelial cells express the high affinity Na\(^+\)-coupled glucose carrier SGLT1. Ussing chamber experiments revealed electrogenic glucose transport across the endometrium in wild type (\(Slc5a1^{+/+}\)) but not in SGLT1 defcient (\(Slc5a1^{−/−}\)) mice. Endometrial glycogen content, litter size and weight of offspring at birth were signifcantly lower in \(Slc5a1^{−/−}\) mice. In humans, \(SLC5A1\) expression was upregulated upon decidualization of primary endometrial stromal cells. Endometrial \(SLC5A1\) expression during the implantation window was attenuated in patients with recurrent pregnancy loss when compared with control subjects. Our fndings reveal a novel mechanism establishing adequate endometrial glycogen stores for pregnancy. Disruption of this histiotrophic pathway leads to adverse pregnancy outcome. KW - biology KW - embryology KW - intrauterine growth KW - paediatric research Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173814 VL - 7 ER -