Specific Reprogramming of Alpha Cells to Insulin-Producing Cells by Short Glucagon Promoter-Driven Pdx1 and MafA

Abstract Endogenous reprogramming of pancreas-derived non-beta cells into insulin-producing cells is a promising approach to treat type 1 diabetes (T1D). One strategy that has yet to be explored is the specific delivery of insulin-producing essential genes, Pdx1 and MafA, to pancreatic alpha cells to reprogram the cells into insulin-producing cells in an adult pancreas. In this study, we utilized an alpha cell-specific glucagon (GCG) promoter to drive Pdx1 and MafA transcription factors to reprogram alpha cells to insulin-producing cells in chemically induced and autoimmune diabetic mice. Our results showed that a combination of a short glucagon-specific promoter with AAV serotype 8 can be used to successfully deliver Pdx1 and MafA into alpha cells in the mouse pancreas. Pdx1 and MafA expression specifically in alpha cells was also able to correct hyperglycemia in both induced and autoimmune diabetic mice. With this technology, targeted gene specificity and reprogramming were accomplished with an alpha-specific promotor combined with an AAV-specific serotype and provide an initial basis to develop a novel therapy for the treatment of T1D.

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Specific Reprogramming of Alpha Cells to Insulin-Producing Cells by Short Glucagon Promoter-Driven Pdx1 and MafA

10.21203/rs.3.rs-904829/v3 ◽

2021 ◽

Author(s):

Ping Guo ◽

Ting Zhang ◽

Aiping Lu ◽

Chiyo Shiota ◽

Matthieu Huard ◽

...

Keyword(s):

Type 1 Diabetes ◽

Alpha Cells ◽

Diabetic Mice ◽

Novel Therapy ◽

Mouse Pancreas ◽

Pancreatic Alpha Cells ◽

Insulin Producing Cells ◽

Chemically Induced ◽

Initial Basis

Abstract Endogenous reprogramming of pancreas-derived non-beta cells into insulin-producing cells is a promising approach to treat type 1 diabetes (T1D). One strategy that has yet to be explored is the specific delivery of insulin-producing essential genes, Pdx1 and MafA, to pancreatic alpha cells to reprogram the cells into insulin-producing cells in an adult pancreas. In this study, we utilized an alpha cell-specific glucagon (GCG) promoter to drive Pdx1 and MafA transcription factors to reprogram alpha cells to insulin-producing cells in chemically induced and autoimmune diabetic mice. Our results showed that a combination of a short glucagon-specific promoter with AAV serotype 8 can be used to successfully deliver Pdx1 and MafA into alpha cells in the mouse pancreas. Pdx1 and MafA expression specifically in alpha cells was also able to correct hyperglycemia in both induced and autoimmune diabetic mice. With this technology, targeted gene specificity and reprogramming were accomplished with an alpha-specific promotor combined with an AAV-specific serotype and provide an initial basis to develop a novel therapy for the treatment of T1D.

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A nanofibrous encapsulation device for safe delivery of insulin-producing cells to treat type 1 diabetes

Science Translational Medicine ◽

10.1126/scitranslmed.abb4601 ◽

2021 ◽

Vol 13 (596) ◽

pp. eabb4601

Author(s):

Xi Wang ◽

Kristina G. Maxwell ◽

Kai Wang ◽

Daniel T. Bowers ◽

James A. Flanders ◽

...

Keyword(s):

Type 1 Diabetes ◽

Stem Cell ◽

Cell Penetration ◽

Β Cells ◽

Safe Delivery ◽

Insulin Producing Cells ◽

Chemically Induced ◽

Immunocompetent Mice ◽

Highly Porous

Transplantation of stem cell–derived β (SC-β) cells represents a promising therapy for type 1 diabetes (T1D). However, the delivery, maintenance, and retrieval of these cells remain a challenge. Here, we report the design of a safe and functional device composed of a highly porous, durable nanofibrous skin and an immunoprotective hydrogel core. The device consists of electrospun medical-grade thermoplastic silicone-polycarbonate-urethane and is soft but tough (~15 megapascal at a rupture strain of >2). Tuning the nanofiber size to less than ~500 nanometers prevented cell penetration while maintaining maximum mass transfer and decreased cellular overgrowth on blank (cell-free) devices to as low as a single-cell layer (~3 micrometers thick) when implanted in the peritoneal cavity of mice. We confirmed device safety, indicated as continuous containment of proliferative cells within the device for 5 months. Encapsulating syngeneic, allogeneic, or xenogeneic rodent islets within the device corrected chemically induced diabetes in mice and cells remained functional for up to 200 days. The function of human SC-β cells was supported by the device, and it reversed diabetes within 1 week of implantation in immunodeficient and immunocompetent mice, for up to 120 and 60 days, respectively. We demonstrated the scalability and retrievability of the device in dogs and observed viable human SC-β cells despite xenogeneic immune responses. The nanofibrous device design may therefore provide a translatable solution to the balance between safety and functionality in developing stem cell–based therapies for T1D.

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Pancreatic Alpha-Cells Contribute Together With Beta-Cells to CXCL10 Expression in Type 1 Diabetes

Frontiers in Endocrinology ◽

10.3389/fendo.2020.00630 ◽

2020 ◽

Vol 11 ◽

Author(s):

Laura Nigi ◽

Noemi Brusco ◽

Giuseppina E. Grieco ◽

Giada Licata ◽

Lars Krogvold ◽

...

Keyword(s):

Type 1 Diabetes ◽

Beta Cells ◽

Alpha Cells ◽

Pancreatic Alpha Cells

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FAILURE OF PANCREATIC ALPHA CELLS TO RESPOND TO HYPOGLYCEMIA IS LINKED TO IMPAIRED GLUTAMATE RECEPTOR SIGNALING IN DIABETES

10.1101/2021.08.11.455935 ◽

2021 ◽

Author(s):

Julia Katharina Panzer ◽

Alejandro Tamayo ◽

Alejandro Caicedo

Keyword(s):

Type 1 Diabetes ◽

Glucagon Secretion ◽

Kainate Receptors ◽

Kainate Receptor ◽

Allosteric Modulators ◽

Alpha Cells ◽

Receptor Signaling ◽

Pancreatic Alpha Cells ◽

Positive Allosteric Modulators

Glucagon secretion from the pancreatic alpha cells is crucial to prevent hypoglycemia. People with type 1 diabetes, however, lose this glucoregulatory mechanism and are susceptible to dangerous insulin treatment-induced hypoglycemia. We established that activating glutamate receptors of the AMPA/kainate type in alpha cells is needed for decreases in glucose levels to elicit full glucagon responses from mouse and human islets. We performed functional studies using living pancreas slices from donors with type 1 diabetes and found that alpha cells had normal glucagon content and responded typically to KCl depolarization, but failed to respond to decreases in glucose concentration and had severely impaired AMPA/kainate receptor signaling. Reactivating residual AMPA/kainate receptor function with the positive allosteric modulators cyclothiazide and aniracetam partially rescued glucagon secretion in response to hypoglycemia. Positive allosteric modulators of AMPA/kainate receptors already approved to treat other conditions could thus be repurposed to prevent hypoglycemia and improve management of diabetes.

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