Applying CRISPR Screen in Diabetes Research

Transition from preclinical to clinical application of CTLA4-Ig co-stimulation blockage in beta-cell replacement therapy

Beta-cell replacement therapies, including islet and pancreas transplantation, offer promising results in term of glycemic control for patients with type 1 diabetes experiencing high glycemic variability and severe hypoglycemia. However, long-term insulin independence remains challenging due to progressive graft function decline. Immunosuppressive regimens, especially calcineurin inhibitors such as tacrolimus, are known to be diabetogenic, contributing to the paradox of impaired beta-cell function in a diabetes treatment setting. Recent studies have focused on CTLA4-Ig (e.g., belatacept) as a potential alternative to calcineurin inhibitors, showing promising results in preclinical and clinical models. This review summarizes key advancements and remaining challenges in CTLA4 applications for beta-cell replacement. First, genetic engineering approaches aiming for CTLA4 expression in islets demonstrated initial success in delaying rejection but remain hindered by immune escape and limited integration efficacy. Coating techniques and exogenous CTLA4-Ig administration offer simpler, albeit transient, immunosuppressive effects, which, combined with encapsulation technologies, can improve graft survival. In non-human primate models, islet transplantation with immunosuppressant regimen using CTLA4-Ig combined with agents such as sirolimus or anti-CD154 has shown extended insulin independence, though full immune tolerance remains elusive. A limited number of human studies using belatacept for beta-cell replacement indicate reduced HbA1c levels and avoidance of severe hypoglycemia, yet consistent absence of rejection remains unachieved. Future research on BCR with CTLA4-Ig should explore graft survival in human islets transplantation and refine immunosuppressive protocols to leverage CTLA4-Ig potential in improving long-term graft function, thus enhancing the sustainability of CTLA4-Ig in clinical beta-cell replacement approach.

Exploring retinal degenerative diseases through CRISPR-based screening

The CRISPR (Clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated protein9) system has emerged as a powerful genetic tool, gaining global recognition as a versatile and efficient gene-editing technique. Its transformation into a high-throughput research platform, CRISPR Screening, has demonstrated wide applicability across various fields such as cancer biology, virology, and drug target discovery, resulting in significant advances. However, its potential in studying retinal degenerative diseases remains largely unexplored, despite the urgent need for effective treatments arising from an incomplete understanding of disease mechanisms. This review aims to present a comprehensive overview of the evolution and current state of CRISPR tools and CRISPR screening methodologies. Noteworthy pioneering studies utilizing these technologies are discussed, alongside experimental design guidelines, including positive and negative selection strategies and delivery methods for sgRNAs (single guide RNAs) and Cas proteins. Furthermore, we explore existing in vitro models appropriate for CRISPR screening in retinal research and identify relevant research questions that could be addressed through this approach. It is anticipated that this review will stimulate innovation in retinal research, facilitating a deeper comprehension of retinal pathophysiology and paving the way for groundbreaking therapeutic interventions and enhanced patient outcomes in the management of retinal degenerative disorders.

Genome-scale CRISPR-Cas9 screening in stem cells: theories, applications and challenges

Due to the rapid development of stem cell technology, there have been tremendous advances in molecular biological and pathological research, cell therapy as well as organoid technologies over the past decades. Advances in genome editing technology, particularly the discovery of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-related protein 9 (Cas9), have further facilitated the rapid development of stem cell researches. The CRISPR-Cas9 technology now goes beyond creating single gene editing to enable the inhibition or activation of endogenous gene loci by fusing inhibitory (CRISPRi) or activating (CRISPRa) domains with deactivated Cas9 proteins (dCas9). These tools have been utilized in genome-scale CRISPRi/a screen to recognize hereditary modifiers that are synergistic or opposing to malady mutations in an orderly and fair manner, thereby identifying illness mechanisms and discovering novel restorative targets to accelerate medicinal discovery investigation. However, the application of this technique is still relatively rare in stem cell research. There are numerous specialized challenges in applying large-scale useful genomics approaches to differentiated stem cell populations. Here, we present the first comprehensive review on CRISPR-based functional genomics screening in the field of stem cells, as well as practical considerations implemented in a range of scenarios, and exploration of the insights of CRISPR-based screen into cell fates, disease mechanisms and cell treatments in stem cell models. This review will broadly benefit scientists, engineers and medical practitioners in the areas of stem cell research.

Application of CRISPR-Cas9 technology in diabetes research

Diabetes is a chronic disorder with rapidly increasing prevalence that is a major global issue of our current era. There are two major types of diabetes. Polygenic forms of diabetes include type 1 diabetes (T1D) and type 2 diabetes (T2D) and its monogenic forms are maturity-onset diabetes of the young (MODY) and neonatal diabetes mellitus (NDM). There are no permanent therapeutic approaches for diabetes and current therapies rely on regular administration of various drugs or insulin injection. Recently, gene editing strategies have offered new promise for treating genetic disorders. Targeted genome editing is a fast-growing technology, recruiting programmable nucleases to specifically modify target genomic sequences. These targeted nucleases generate double-strand breaks at target regions in the genome, which induce cellular repair pathways including non-homologous end joining (NHEJ) and homology-directed repair (HDR). Clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) is a novel gene-editing system, permitting precise genome modification. CRISPR/Cas9 has great potential for various applications in diabetic research such as gene screening, generation of diabetic animal models and treatment. In this article, gene-editing strategies are summarized with a focus on the CRISPR/Cas9 approach in diabetes research.

β Cell Stress and Endocrine Function During T1D: What Is Next to Discover?

Canonically, type 1 diabetes (T1D) is a disease characterized by autoreactive T cells as perpetrators of endocrine dysfunction and β cell death in the spiral toward loss of β cell mass, hyperglycemia, and insulin dependence. β Cells have mostly been considered as bystanders in a flurry of autoimmune processes. More recently, our framework for understanding and investigating T1D has evolved. It appears increasingly likely that intracellular β cell stress is an important component of T1D etiology/pathology that perpetuates autoimmunity during the progression to T1D. Here we discuss the emerging and complex role of β cell stress in initiating, provoking, and catalyzing T1D. We outline the bridges between hyperglycemia, endoplasmic reticulum stress, oxidative stress, and autoimmunity from the viewpoint of intrinsic β cell (dys)function, and we extend this discussion to the potential role for a therapeutic β cell stress-metabolism axis in T1D. Lastly, we mention research angles that may be pursued to improve β cell endocrine function during T1D. Biology gleaned from studying T1D will certainly overlap to innovate therapeutic strategies for T2D, and also enhance the pursuit of creating optimized stem cell-derived β cells as endocrine therapy.