Light-Mediated Enhancement of Glucose-Stimulated Insulin Release of Optogenetically Engineered Human Pancreatic Beta-Cells.

Enhancement of glucose-stimulated insulin secretion (GSIS) in exogenously delivered pancreatic ß-cells is desirable, for example, to overcome the insulin resistance manifested in type 2 diabetes or to reduce the number of ß-cells for supporting homeostasis of blood sugar in type 1 diabetes. Optogenetically engineered cells can potentiate their function with exposure to light. Given that cyclic adenosine monophosphate (cAMP) mediates GSIS, we surmised that optoamplification of GSIS is feasible in human ß-cells carrying a photoactivatable adenylyl cyclase (PAC). To this end, human EndoC-ßH3 cells were engineered to express a blue-light-activated PAC, and a workflow was established combining the scalable manufacturing of pseudoislets (PIs) with efficient adenoviral transduction, resulting in over 80% of cells carrying PAC. Changes in intracellular cAMP and GSIS were determined with the photoactivation of PAC in vitro as well as after encapsulation and implantation in mice with streptozotocin-induced diabetes. cAMP rapidly rose in ß-cells expressing PAC with illumination and quickly declined upon its termination. Light-induced amplification in cAMP was concomitant with a greater than 2-fold GSIS vs ß-cells without PAC in elevated glucose. The enhanced GSIS retained its biphasic pattern, and the rate of oxygen consumption remained unchanged. Diabetic mice receiving the engineered ß-cell PIs exhibited improved glucose tolerance upon illumination compared to those kept in the dark or not receiving cells. The findings support the use of optogenetics for molecular customization of the ß-cells toward better treatments for diabetes without the adverse effects of pharmacological approaches.

Non-xenogeneic expansion and definitive endoderm differentiation of human pluripotent stem cells in an automated bioreactor.

Scalable processes are requisite for the robust biomanufacturing of human pluripotent stem cell (hPSC)-derived therapeutics. Toward this end, we demonstrate the xeno-free expansion and directed differentiation of human embryonic and induced pluripotent stem cells to definitive endoderm (DE) in a controlled stirred suspension bioreactor (SSB). Based on previous work on converting hPSCs to insulin-producing progeny, differentiation of two hPSC lines was optimized in planar cultures yielding up to 87% FOXA2+ /SOX17+ cells. Next, hPSCs were propagated in an SSB with controlled pH and dissolved oxygen. Cultures displayed a 10- to 12-fold increase in cell number over 5-6 days with the maintenance of pluripotency (>85% OCT4+ ) and viability (>85%). For differentiation, SSB cultures yielded up to 89% FOXA2+ /SOX17+ cells or ~ 8 DE cells per seeded hPSC. Specification to DE cell fate was consistently more efficient in the bioreactor compared to planar cultures. Hence, a tunable strategy is established that is suitable for the xeno-free manufacturing of DE cells from different hPSC lines in scalable SSBs. This study advances bioprocess development for producing a wide gamut of human DE cell-derived therapeutics.

Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook.

Ammonia is a key chemical produced in huge quantities worldwide. Its primary industrial production is via the Haber-Bosch method; a process requiring high temperatures and pressures, and consuming large amounts of energy. In the past two decades, several alternatives to the existing process have been proposed, including the electrochemical synthesis. The present paper reviews literature concerning this approach and the experimental research carried out in aqueous, molten salt, or solid electrolyte cells, over the past three years. The electrochemical systems are grouped, described, and discussed according to the operating temperature, which is determined by the electrolyte used, and their performance is valuated. The problems which need to be addressed further in order to scale-up the electrochemical synthesis of ammonia to the industrial level are examined.