Combinatorial genetic engineering strategy for immune protection of stem cell-derived beta cells by chimeric antigen receptor regulatory T cells.

Regenerative medicine is a rapidly expanding field harnessing human pluripotent stem cell (hPSC)-derived cells and tissues to treat many diseases, including type 1 diabetes. However, graft immune protection remains a key challenge. Chimeric antigen receptor (CAR) technology confers new specificities to effector T cells and immunosuppressive regulatory T cells (Tregs).

Role of Sec61α2 Translocon in Insulin Biosynthesis.

Translocational regulation of proinsulin biosynthesis in pancreatic β-cells is unknown, although several studies have reported an important accessory role for the Translocon-Associated Protein complex to assist preproinsulin delivery into the endoplasmic reticulum via the heterotrimeric Sec61 translocon (comprising α, β, and γ subunits). The actual protein-conducting channel is the α-subunit encoded either by Sec61A1 or its paralog Sec61A2. Although the underlying channel selectivity for preproinsulin translocation is unknown, almost all studies of Sec61α to date have focused on Sec61α1.

Peptide-Coated Polycaprolactone-Benzalkonium Chloride Nanocapsules for Targeted Drug Delivery to the Pancreatic β-Cell.

Targeting current therapies to treat or prevent the loss of pancreatic islet β-cells in Type 1 Diabetes (T1D) may provide improved efficacy and reduce off-target effects. Current efforts to target the β-cell are limited by a lack of β-cell-specific targets and the inability to test multiple targeting moieties with the same delivery vehicle. Here, we fabricate a tailorable polycaprolactone nanocapsule (NC) in which multiple different targeting peptides can be interchangeably attached for β-cell-specific delivery.

The RNA binding protein HNRNPA2B1 regulates RNA abundance and motor protein activity in neurites.

RNA molecules are localized to subcellular regions through interactions between localization-regulatory cis-elements and trans-acting RNA binding proteins (RBPs). However, the identities of RNAs whose localization is regulated by a specific RBP as well as the impacts of that RNA localization on cell function have generally remained unknown. Here, we demonstrate that the RBP HNRNPA2B1 acts to keep specific RNAs out of neuronal projections.

Harnessing cellular therapeutics for type 1 diabetes mellitus: progress, challenges, and the road ahead.

Type 1 diabetes mellitus (T1DM) is a growing global health concern that affects approximately 8.5 million individuals worldwide. T1DM is characterized by an autoimmune destruction of pancreatic β cells, leading to a disruption in glucose homeostasis.

Cryopreservation of Stem Cell-Derived β-Like Cells Enriches for Insulin-Producing Cells With Improved Function.

The generation of stem cell-derived β-like cells (sBCs) holds promise as not only an abundant insulin-producing cell source for replacement therapy of type 1 diabetes (T1D) but also as an invaluable model system for investigating human β-cell development, immunogenicity, and function. Several groups have developed methodology to direct differentiate human pluripotent stem cells into pancreatic cell populations that include glucose-responsive sBCs. Nevertheless, the process of generating sBCs poses substantial experimental challenges.

Peptide Coated Polycaprolactone-Benzalkonium Chloride Nanocapsules for Targeted Drug Delivery to the Pancreatic β-Cell.

Targeting of current therapies to treat or prevent loss of pancreatic islet β-cells in Type 1 Diabetes (T1D) may provide improved efficacy and reduce off target effects. Current efforts to target the β-cell are limited by a lack of β-cell specific targets and the inability to test multiple targeting moieties with the same delivery vehicle. Here we fabricate a novel tailorable polycaprolactone nanocapsule (NC) where multiple different targeting peptides can be interchangeably attached for β-cell specific delivery.

Sox9 regulates alternative splicing and pancreatic beta cell function.

Despite significant research, mechanisms underlying the failure of islet beta cells that result in type 2 diabetes (T2D) are still under investigation. Here, we report that Sox9, a transcriptional regulator of pancreas development, also functions in mature beta cells. Our results show that Sox9-depleted rodent beta cells have defective insulin secretion, and aging animals develop glucose intolerance, mimicking the progressive degeneration observed in T2D.

The beta cell-immune cell interface in type 1 diabetes (T1D).

Background: T1D is an autoimmune disease in which pancreatic islets of Langerhans are infiltrated by immune cells resulting in the specific destruction of insulin-producing islet beta cells. Our understanding of the factors leading to islet infiltration and the interplay of the immune cells with target beta cells is incomplete, especially in human disease. While murine models of T1D have provided crucial information for both beta cell and autoimmune cell function, the translation of successful therapies in the murine model to human disease has been a challenge.

A fast chemical reprogramming system promotes cell identity transition through a diapause-like state.

Cellular reprogramming by only small molecules holds enormous potentials for regenerative medicine. However, chemical reprogramming remains a slow process and labour intensive, hindering its broad applications and the investigation of underlying molecular mechanisms. Here, through screening of over 21,000 conditions, we develop a fast chemical reprogramming (FCR) system, which significantly improves the kinetics of cell identity rewiring.

Enrichment of stem cell-derived pancreatic beta-like cells and controlled graft size through pharmacological removal of proliferating cells.

Transplantation of limited human cadaveric islets into type 1 diabetic patients results in ∼35 months of insulin independence. Direct differentiation of stem cell-derived insulin-producing beta-like cells (sBCs) that can reverse diabetes in animal models effectively removes this shortage constraint, but uncontrolled graft growth remains a concern. Current protocols do not generate pure sBCs, but consist of only 20%-50% insulin-expressing cells with additional cell types present, some of which are proliferative.

Nutrient-dependent regulation of β-cell proinsulin content.

Insulin is made from proinsulin, but the extent to which fasting/feeding controls the homeostatically regulated proinsulin pool in pancreatic β-cells remains largely unknown. Here, we first examined β-cell lines (INS1E and Min6, which proliferate slowly and are routinely fed fresh medium every 2-3 days) and found that the proinsulin pool size responds to each feeding within 1 to 2 h, affected both by the quantity of fresh nutrients and the frequency with which they are provided. We observed no effect of nutrient feeding on the overall rate of proinsulin turnover as quantified from cycloheximide-chase experiments.

Generation of functional thymic organoids from human pluripotent stem cells.

The thymus is critical for the establishment of a functional and self-tolerant adaptive immune system but involutes with age, resulting in reduced naive T cell output. Generation of a functional human thymus from human pluripotent stem cells (hPSCs) is an attractive regenerative strategy. Direct differentiation of thymic epithelial progenitors (TEPs) from hPSCs has been demonstrated in vitro, but functional thymic epithelial cells (TECs) only form months after transplantation of TEPs in vivo.

Cell Replacement Therapy for Type 1 Diabetes Patients: Potential Mechanisms Leading to Stem-Cell-Derived Pancreatic β-Cell Loss upon Transplant.

Cell replacement therapy using stem-cell-derived insulin-producing β-like cells (sBCs) has been proposed as a practical cure for patients with type one diabetes (T1D). sBCs can correct diabetes in preclinical animal models, demonstrating the promise of this stem cell-based approach. However, in vivo studies have demonstrated that most sBCs, similarly to cadaveric human islets, are lost upon transplantation due to ischemia and other unknown mechanisms.

Human stem cell derived beta-like cells engineered to present PD-L1 improve transplant survival in NOD mice carrying human HLA class I.

There is a critical need for therapeutic approaches that combine renewable sources of replacement beta cells with localized immunomodulation to counter recurrence of autoimmunity in type 1 diabetes (T1D). However, there are few examples of animal models to study such approaches that incorporate spontaneous autoimmunity directed against human beta cells rather than allogenic rejection. Here, we address this critical limitation by demonstrating rejection and survival of transplanted human stem cell-derived beta-like cells clusters (sBCs) in a fully immune competent mouse model with matching human HLA class I and spontaneous diabetes development.

Stem-Cell-Derived β-Like Cells with a Functional PTPN2 Knockout Display Increased Immunogenicity.

Type 1 diabetes is a polygenic disease that results in an autoimmune response directed against insulin-producing beta cells. is a known high-risk type 1 diabetes associated gene expressed in both immune- and pancreatic beta cells, but how genes affect the development of autoimmune diabetes is largely unknown. We employed CRISPR/Cas9 technology to generate a functional knockout of in human pluripotent stem cells (hPSC) followed by differentiating stem-cell-derived beta-like cells (sBC) and detailed phenotypical analyses.

Stem cell-based multi-tissue platforms to model human autoimmune diabetes.

Background: Type 1 diabetes (T1D) is an autoimmune disease in which pancreatic insulin-producing β cells are specifically destroyed by the immune system. Understanding the initiation and progression of human T1D has been hampered by the lack of appropriate models that can reproduce the complexity and heterogeneity of the disease. The development of platforms combining multiple human pluripotent stem cell (hPSC) derived tissues to model distinct aspects of T1D has the potential to provide critical novel insights into the etiology and pathogenesis of the human disease.

From the dish to humans: A stem cell recipe for success.

Islet transplantation has proven to be an effective treatment for type 1 diabetes (T1D) yet is hampered by the shortage of available tissue. Recently, two reports from a Viacyte multicenter clinical trial demonstrate the feasibility, safety, and potential efficacy of transplanting macro-encapsulated human stem cell-derived pancreatic endoderm cells into patients with T1D, highlighting the promise of a stem cell-based therapeutic approach.

Use of Induced Pluripotent Stem Cells to Build Isogenic Systems and Investigate Type 1 Diabetes.

Type 1 diabetes (T1D) is a disease that arises due to complex immunogenetic mechanisms. Key cell-cell interactions involved in the pathogenesis of T1D are activation of autoreactive T cells by dendritic cells (DC), migration of T cells across endothelial cells (EC) lining capillary walls into the islets of Langerhans, interaction of T cells with macrophages in the islets, and killing of β-cells by autoreactive CD8 T cells. Overall, pathogenic cell-cell interactions are likely regulated by the individual's collection of genetic T1D-risk variants.

ENTPD3 Marks Mature Stem Cell-Derived β-Cells Formed by Self-Aggregation In Vitro.

Stem cell-derived β-like cells (sBC) carry the promise of providing an abundant source of insulin-producing cells for use in cell replacement therapy for patients with diabetes, potentially allowing widespread implementation of a practical cure. To achieve their clinical promise, sBC need to function comparably with mature adult β-cells, but as yet they display varying degrees of maturity. Indeed, detailed knowledge of the events resulting in human β-cell maturation remains obscure.

Generation of functional human thymic cells from induced pluripotent stem cells.

Background: The thymus is a glandular organ that is essential for the formation of the adaptive immune system by educating developing T cells. The thymus is most active during childhood and involutes around the time of adolescence, resulting in a severe reduction or absence of naive T-cell output. The ability to generate a patient-derived human thymus would provide an attractive research platform and enable the development of novel cell therapies.