1
|
Farhat R, Aiken J, D'Souza NC, Appadurai D, Hull G, Simonson E, Liggins RT, Riddell MC, Chan O. ZT-01: A novel somatostatin receptor 2 antagonist for restoring the glucagon response to hypoglycaemia in type 1 diabetes. Diabetes Obes Metab 2022; 24:908-917. [PMID: 35060297 DOI: 10.1111/dom.14652] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [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: 10/15/2021] [Revised: 01/02/2022] [Accepted: 01/16/2022] [Indexed: 01/17/2023]
Abstract
AIM To evaluate the pharmacokinetics and efficacy of a novel somatostatin receptor 2 antagonist, ZT-01, to stimulate glucagon release in rats with type 1 diabetes (T1D). METHODS The pharmacokinetics of ZT-01 and PRL-2903 were assessed following intraperitoneal or subcutaneous dosing at 10 mg/kg. We compared the efficacy of ZT-01 with PRL-2903 to prevent hypoglycaemia during an insulin bolus challenge and under hypoglycaemic clamp conditions. RESULTS Within 1 hour after intraperitoneal administration, ZT-01 achieved more than 10-fold higher plasma Cmax compared with PRL-2903. Twenty-four hour exposure was 4.7× and 11.3× higher with ZT-01 by the intraperitoneal and subcutaneous routes, respectively. The median time to reach hypoglycaemia of more than 3.0 mmol/L was 60, 70, and 125 minutes following vehicle, PRL-2903, or ZT-01 administration, respectively. Furthermore, rats receiving ZT-01 had significantly higher glucose nadirs following insulin administration compared with PRL-2903- and vehicle-treated rats. During the hypoglycaemic clamp, ZT-01 increased peak glucagon responses by ~4-fold over PRL-2903. CONCLUSIONS We conclude that ZT-01 may be effective in restoring glucagon responses and preventing the onset of hypoglycaemia in patients with T1D.
Collapse
Affiliation(s)
- Rawad Farhat
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, Utah, USA
| | - Julian Aiken
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Ninoschka C D'Souza
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Daniel Appadurai
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, Utah, USA
| | - Grayson Hull
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, Utah, USA
| | - Eric Simonson
- Zucara Therapeutics, Vancouver, British Columbia, Canada
| | | | - Michael C Riddell
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
- Zucara Therapeutics, Vancouver, British Columbia, Canada
| | - Owen Chan
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, Utah, USA
| |
Collapse
|
2
|
Sejling AS, Wang P, Zhu W, Farhat R, Knight N, Appadurai D, Chan O. Repeated Activation of Noradrenergic Receptors in the Ventromedial Hypothalamus Suppresses the Response to Hypoglycemia. Endocrinology 2021; 162:6052997. [PMID: 33367607 PMCID: PMC7814298 DOI: 10.1210/endocr/bqaa241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 11/19/2022]
Abstract
Activation of the adrenergic system in response to hypoglycemia is important for proper recovery from low glucose levels. However, it has been suggested that repeated adrenergic stimulation may also contribute to counterregulatory failure, but the underlying mechanisms are not known. The aim of this study was to establish whether repeated activation of noradrenergic receptors in the ventromedial hypothalamus (VMH) contributes to blunting of the counterregulatory response by enhancing local lactate production. The VMH of nondiabetic rats were infused with either artificial extracellular fluid, norepinephrine (NE), or salbutamol for 3 hours/day for 3 consecutive days before they underwent a hypoglycemic clamp with microdialysis to monitor changes in VMH lactate levels. Repeated exposure to NE or salbutamol suppressed both the glucagon and epinephrine responses to hypoglycemia compared to controls. Furthermore, antecedent NE and salbutamol treatments raised extracellular lactate levels in the VMH. To determine whether the elevated lactate levels were responsible for impairing the hormone response, we pharmacologically inhibited neuronal lactate transport in a subgroup of NE-treated rats during the clamp. Blocking neuronal lactate utilization improved the counterregulatory hormone responses in NE-treated animals, suggesting that repeated activation of VMH β2-adrenergic receptors increases local lactate levels which in turn, suppresses the counterregulatory hormone response to hypoglycemia.
Collapse
Affiliation(s)
- Anne-Sophie Sejling
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Dyrehavevej, Denmark
- Current Affiliation: A.S. is currently with Novo Nordisk A/S
| | - Peili Wang
- Department of Internal Medicine-Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Wanling Zhu
- Department of Internal Medicine-Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Rawad Farhat
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Nicholas Knight
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Daniel Appadurai
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Owen Chan
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
- Correspondence: Dr. Owen Chan, PhD, University of Utah, Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, 15 North 2030 East, Rm 2420B, Salt Lake City, UT 84112, USA.
| |
Collapse
|
3
|
Appadurai D, Gay L, Moharir A, Lang MJ, Duncan MC, Schmidt O, Teis D, Vu TN, Silva M, Jorgensen EM, Babst M. Plasma membrane tension regulates eisosome structure and function. Mol Biol Cell 2019; 31:287-303. [PMID: 31851579 PMCID: PMC7183764 DOI: 10.1091/mbc.e19-04-0218] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Eisosomes are membrane furrows at the cell surface of yeast that have been shown to function in two seemingly distinct pathways, membrane stress response and regulation of nutrient transporters. We found that many stress conditions affect both of these pathways by changing plasma membrane tension and thus the morphology and composition of eisosomes. For example, alkaline stress causes swelling of the cell and an endocytic response, which together increase membrane tension, thereby flattening the eisosomes. The flattened eisosomes affect membrane stress pathways and release nutrient transporters, which aids in their down-regulation. In contrast, glucose starvation or hyperosmotic shock causes cell shrinking, which results in membrane slack and the deepening of eisosomes. Deepened eisosomes are able to trap nutrient transporters and protect them from rapid endocytosis. Therefore, eisosomes seem to coordinate the regulation of both membrane tension and nutrient transporter stability.
Collapse
Affiliation(s)
- Daniel Appadurai
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - Lincoln Gay
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - Akshay Moharir
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - Michael J Lang
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Mara C Duncan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Oliver Schmidt
- Division of Cell Biology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - David Teis
- Division of Cell Biology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Thien N Vu
- School of Biological Sciences, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112
| | - Malan Silva
- School of Biological Sciences, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112
| | - Erik M Jorgensen
- School of Biological Sciences, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112
| | - Markus Babst
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| |
Collapse
|
4
|
Moharir A, Gay L, Appadurai D, Keener J, Babst M. Eisosomes are metabolically regulated storage compartments for APC-type nutrient transporters. Mol Biol Cell 2018; 29:2113-2127. [PMID: 29927345 PMCID: PMC6232963 DOI: 10.1091/mbc.e17-11-0691] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Eisosomes are lipid domains of the yeast plasma membrane that share similarities to caveolae of higher eukaryotes. Eisosomes harbor APC-type nutrient transporters for reasons that are poorly understood. Our analyses support the model that eisosomes function as storage compartments, keeping APC transporters in a stable, inactive state. By regulating eisosomes, yeast is able to balance the number of proton-driven APC transporters with the proton-pumping activity of Pma1, thereby maintaining the plasma membrane proton gradient. Environmental or metabolic changes that disrupt the proton gradient cause the rapid restructuring of eisosomes and results in the removal of the APC transporters from the cell surface. Furthermore, we show evidence that eisosomes require the presence of APC transporters, suggesting that regulating activity of nutrient transporters is a major function of eisosomes.
Collapse
Affiliation(s)
- Akshay Moharir
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - Lincoln Gay
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - Daniel Appadurai
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - James Keener
- Department of Mathematics, University of Utah, Salt Lake City, UT 84112
| | - Markus Babst
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| |
Collapse
|