SUMMARY Genome wide association studies (GWAS) have increased our knowledge of loci associated with a range of human diseases. However, applying such findings to elucidate pathophysiology and promote drug discovery remains challenging. Here, we created isogenic human embryonic stem cells (hESCs) with mutations in GWAS-identified susceptibility genes for type 2 diabetes. In pancreatic betalike cells differentiated from these lines, we found that mutations in CDKAL1, KCNQ1 and KCNJ11 led to impaired glucose secretion in vitro and in vivo, coinciding with defective glucose homeostasis. CDKAL1 mutant insulin+ cells were also hypersensitive to glucolipotoxicity. A high-content chemical screen identified a candidate drug that rescued CDKAL1 specific defects in vitro and in vivo by inhibiting the FOS/JUN pathway. Our approach of a proof-of-principle platform, which uses isogenic hESCs for functional evaluation of GWAS-identified loci and identification of a drug candidate that rescues gene-specific defects, paves the way for precision therapy of metabolic diseases.

Background: Increasing evidence suggests that cardiac arrhythmias are frequent clinical features of coronavirus disease 2019 (COVID-19). Sinus node damage may lead to bradycardia. However, it is challenging to explore human sinoatrial node (SAN) pathophysiology due to difficulty in isolating and culturing human SAN cells. Embryonic stem cells (ESCs) can be a source to derive human SAN-like pacemaker cells for disease modeling. Methods: We used both a hamster model and human ESC (hESC)–derived SAN-like pacemaker cells to explore the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on the pacemaker cells of the heart. In the hamster model, quantitative real-time polymerase chain reaction and immunostaining were used to detect viral RNA and protein, respectively. We then created a dual knock-in SHOX2:GFP;MYH6:mCherry hESC reporter line to establish a highly efficient strategy to derive functional human SAN-like pacemaker cells, which was further characterized by single-cell RNA sequencing. Following exposure to SARS-CoV-2, quantitative real-time polymerase chain reaction, immunostaining, and RNA sequencing were used to confirm infection and determine the host response of hESC-SAN–like pacemaker cells. Finally, a high content chemical screen was performed to identify drugs that can inhibit SARS-CoV-2 infection, and block SARS-CoV-2–induced ferroptosis. Results: Viral RNA and spike protein were detected in SAN cells in the hearts of infected hamsters. We established an efficient strategy to derive from hESCs functional human SAN-like pacemaker cells, which express pacemaker markers and display SAN-like action potentials. Furthermore, SARS-CoV-2 infection causes dysfunction of human SAN-like pacemaker cells and induces ferroptosis. Two drug candidates, deferoxamine and imatinib, were identified from the high content screen, able to block SARS-CoV-2 infection and infection-associated ferroptosis. Conclusions: Using a hamster model, we showed that primary pacemaker cells in the heart can be infected by SARS-CoV-2. Infection of hESC-derived functional SAN-like pacemaker cells demonstrates ferroptosis as a potential mechanism for causing cardiac arrhythmias in patients with COVID-19. Finally, we identified candidate drugs that can protect the SAN cells from SARS-CoV-2 infection.

We have successfully demonstrated an innovative cell sourcing strategy that facilitates our efforts to achieve clinical translation of our high fidelity, patient-specific ears for auricular reconstruction utilizing only half of the requisite auricular chondrocytes to fabricate mature elastic cartilage.

No abstract

An inadequate response from macrophages, key orchestrators of the wound healing process, has been implicated in the pathophysiology of impaired healing in diabetes. This study explored the utility of nanoparticles presenting the α‐gal (Galα1‐3Galβ1‐4GlcNAc‐R) epitope to induce anti‐Gal antibody‐mediated local transient recruitment of macrophages to accelerate wound closure and healing in a diabetic murine model. α1,3galactosyltrasferase knockout mice were stimulated to produce anti‐Gal antibodies and subsequently diabetes was induced by streptozotocin‐induced β‐cell destruction. Six mm full‐thickness skin wounds were made and α‐gal nanoparticles (AGN) were topically applied on postwounding days 0 and 1. Wounds were analysed histologically for macrophage invasion and markers of wound healing, including epithelialization, vascularization and granulation tissue deposition through postoperative day 12. We found that application of AGN transiently but significantly increased macrophage recruitment into the wounds of diabetic mice. Treated wounds demonstrated more rapid closure and enhanced wound healing as demonstrated by significantly accelerated rates of epithelialization, vascularization and granulation tissue deposition. Thus, topical treatment of full‐thickness wounds in diabetic mice with α‐gal nanoparticles induced a transient but significant increase in macrophage recruitment resulting in an accelerated rate of wound healing. Using α‐gal nanoparticles as a topical wound healing adjunct is a simple, safe and effective means of augmenting dysregulated macrophage recruitment present in the diabetic state.