HNF4A and HNF1A exhibit tissue specific target gene regulation in pancreatic beta cells and hepatocytes.

HNF4A and HNF1A encode transcription factors that are important for the development and function of the pancreas and liver. Mutations in both genes have been directly linked to Maturity Onset Diabetes of the Young (MODY) and type 2 diabetes (T2D) risk. To better define the pleiotropic gene regulatory roles of HNF4A and HNF1A, we generated a comprehensive genome-wide map of their binding targets in pancreatic and hepatic cells using ChIP-Seq. HNF4A was found to bind and regulate known (ACY3, HAAO, HNF1A, MAP3K11) and previously unidentified (ABCD3, CDKN2AIP, USH1C, VIL1) loci in a tissue-dependent manner. Functional follow-up highlighted a potential role for HAAO and USH1C as regulators of beta cell function. Unlike the loss-of-function HNF4A/MODY1 variant I271fs, the T2D-associated HNF4A variant (rs1800961) was found to activate AKAP1, GAD2 and HOPX gene expression, potentially due to changes in DNA-binding affinity. We also found HNF1A to bind to and regulate GPR39 expression in beta cells. Overall, our studies provide a rich resource for uncovering downstream molecular targets of HNF4A and HNF1A that may contribute to beta cell or hepatic cell (dys)function, and set up a framework for gene discovery and functional validation.

Harnessing Human Pluripotent Stem Cell-Derived Pancreatic In Vitro Models for High-Throughput Toxicity Testing and Diabetes Drug Discovery.

The long-standing goals in diabetes research are to improve ß-cell survival, functionality and increase ß-cell mass. Current strategies to manage diabetes progression are still not ideal for sustained maintenance of normoglycemia, thereby increasing demand for the development of novel drugs. Available pancreatic cell lines, cadaveric islets, and their culture methods and formats, either 2D or 3D, allow for multiple avenues of experimental design to address diverse aims in the research setting. More specifically, these pancreatic cells have been employed in toxicity testing, diabetes drug screens, and with careful curation, can be optimized for use in efficient high-throughput screenings (HTS). This has since spearheaded the understanding of disease progression and related mechanisms, as well as the discovery of potential drug candidates which could be the cornerstone for diabetes treatment. This book chapter will touch on the pros and cons of the most widely used pancreatic cells, including the more recent human pluripotent stem cell-derived pancreatic cells, and HTS strategies (cell models, design, readouts) that can be used for the purpose of toxicity testing and diabetes drug discovery.

Sternal cleft reconstruction with acellular dermal matrix and full-thickness calvarial graft.

We describe reconstruction of a sternal cleft in a neonate using acellular dermal matrix, full-thickness calvarial bone graft and myocutaneous pectoralis flaps.

Safety and efficacy of probiotic supplements as adjunctive therapies in patients with COVID-19: A systematic review and meta-analysis.

BACKGROUND AND AIMS: Oral probiotic supplementation may be a beneficial adjunctive therapy for patients with symptomatic COVID-19. However, its safety and efficacy are unclear. We aimed to investigate how probiotic supplementation impacts COVID-19 symptom trajectory and patient outcomes by conducting a systematic review and meta-analysis of randomized controlled trials (RCTs). METHODS: RCTs randomizing patients with COVID-19 to probiotics were searched in PubMed Central, Embase, CINAHL, and Cochrane Library from inception to July 31, 2022. We performed a random-effects pairwise meta-analysis for all outcomes using the restricted maximum likelihood (REML) estimator. We used the GRADE approach to assess the certainty of the evidence. RESULTS: A total of 1027 participants from eight RCT studies were included in the meta-analysis. Probiotic supplements probably reduce the incidence of diarrhea (RR 0.61 [0.43 to 0.87]; moderate certainty) and probably reduce cough or dyspnea compared to placebo/standard care (RR 0.37 [0.19 to 0.73]; moderate certainty). Probiotic supplements may improve composite endpoint measured by clinical escalation or mortality compared to placebo (RR 0.41 [0.18 to 0.93]; low certainty evidence); however, they may not significantly reduce the need for clinical escalation (RR 0.57 [0.31 to 1.07]; low certainty evidence) or mortality (RR 0.50 [0.20 to 1.29]; low certainty evidence). In addition, the probiotic supplement is associated with reduced adverse events (RR 0.62 [0.46 to 0.83]; moderate certainty). CONCLUSION: Early probiotic supplement is a safe and effective adjunctive therapy that reduces the risk of symptoms and health care burden related to COVID-19 across all severity types.

Generating pancreatic beta-like cells from human pluripotent stem cells.

Diabetes is a major healthcare burden globally, affecting over 463 million people today, according to the International Diabetes Federation. The most common types of diabetes are Type I diabetes (T1D) and Type II diabetes (T2D), characterized by hyperglycemia due to autoimmune destruction of ß cells (T1D) and ß cell dysfunction, usually on a background of insulin resistance (T2D). There is currently no cure for diabetes, and patients with T1D require lifelong insulin therapy. Additionally, while most cases of T2D can be managed by lifestyle and diet modifications, with or without antidiabetic drugs, severe cases of T2D may also require insulin therapy. The only means to restore stable euglycemia in these patients is now via whole pancreas or islet transplantation. However, this is limited by the scarcity of donors. In recent years, advances in human pluripotent stem cell (hPSC) technologies and pancreatic ß cell differentiation protocols have opened up new potential avenues for cell replacement therapies for diabetes. These advances have also created opportunities to use hPSC-derived ß-like cells for studies of disease mechanisms and drug discovery, which in turn have the potential to lead to better therapies for diabetes patients. Here, we describe the protocol used in our laboratory to generate ß-like cells from hPSCs to study the mechanisms underlying various types of diabetes.