Parallel use of pluripotent human stem cell lung and heart models provide new insights for treatment of SARS-CoV-2 (preprint)

SARS-CoV-2 primarily infects the respiratory tract, but pulmonary and cardiac complications occur in severe COVID-19. To elucidate molecular mechanisms in the lung and heart, we conducted paired experiments in human stem cell-derived lung alveolar type II (AT2) epithelial cell and cardiac cultures infected with SARS-CoV-2. With CRISPR-Cas9 mediated knock-out of ACE2, we demonstrated that angiotensin converting enzyme 2 (ACE2) was essential for SARS-CoV-2 infection of both cell types but further processing in lung cells required TMPRSS2 while cardiac cells required the endosomal pathway. Host responses were significantly different; transcriptome profiling and phosphoproteomics responses depended strongly on the cell type. We identified several antiviral compounds with distinct antiviral and toxicity profiles in lung AT2 and cardiac cells, highlighting the importance of using several relevant cell types for evaluation of antiviral drugs. Our data provide new insights into rational drug combinations for effective treatment of a virus that affects multiple organ systems.

Bromodomain Inhibition Blocks Inflammation-Induced Cardiac Dysfunction and SARS-CoV2 Infection (preprint)

Cardiac injury and dysfunction occur in COVID-19 patients and increase the risk of mortality. Causes are ill defined, but could be direct cardiac infection and/or ‘cytokine-storm’ induced dysfunction. To identify mechanisms and discover cardio-protective drugs, we use a state-of-the-art pipeline combining human cardiac organoids with high throughput phosphoproteomics and single nuclei RNA sequencing. We identify that ‘cytokine-storm’ induced diastolic dysfunction can be caused by a cocktail of interferon gamma, interleukin 1β and poly(I:C) and also human COVID-19 serum. Bromodomain protein 4 (BRD4) is activated along with pathology driving fibrotic and induced nitric oxide synthase genes. BRD inhibitors fully recover function in hCO and totally prevent death in a cytokine-storm mouse model. BRD inhibition decreases transcription of multiple genes, including fibrotic, induced nitric oxide synthase and ACE2, and prevention of cardiac infection with SARS-CoV2. Thus, BRD inhibitors are promising candidates to prevent COVID-19 mediated cardiac damage.Funding: We acknowledge grant and fellowship support from the National Health and Medical Research Council of Australia (J.E.H., M.J.S., C.R.E., T.B.), Heart Foundation of Australia (J.E.H.), QIMR Berghofer Medical Research Institute (J.E.H.), The Stafford Fox Foundation (E.R.P.), the Royal Children’s Hospital Foundation (E.R.P.), Australian Research Council Strategic Initiative in Stem Cell Science (Stem Cells Australia) (E.R.P. and J.E.H.) and the Medical Research Future Fund (MRFF9200008) (J.E.H., T.B., M.J.S., K.P.A.MD., C.R.E., E.R.P.). M.J.S. is supported by Health and Medical Research Council of Australia Program (APP1132519) and Investigator (APP1173958) grants. A.S. is also supported by Investigator grant (APP1173880). The Murdoch Children’s Research Institute is supported by the Victorian Government’s Operational Infrastructure Support Program. This project received support from Dynomics Inc. J.E.H. is supported by a Snow Medical Fellowship. Conflict of Interest: R.J.M., J.E.H., G.A.Q.-R., D.M.T. and E.R.P. are listed as co-inventors on pending patents held by The University of Queensland and QIMR Berghofer Medical Research Institute that relate to cardiac organoid maturation and putative cardiac regeneration therapeutics. J.E.H. is a coinventor on licensed patents held by the University of Goettingen. R.J.M, E.R.P., D.M.T., B.G. and J.E.H. are co-founders, scientific advisors and stockholders in Dynomics Inc. D.M.T. and B.G. are employees of Dynomics Inc. /Dynomics Pty Ltd. QIMR Berghofer Medical Research Institute has filed a patent on the use of BRD inhibitors. Ethical Approval: Animal work was approved by the QIMR Berghofer Medical Research Institute Animal Ethics Committee. Ethical approval for the use of human embryonic stem cells (hESCs) was obtained from QIMR Berghofer’s Ethics Committee and was carried out in accordance with the National Health and Medical Research Council of Australia (NHMRC) regulations. Procedures complied with standards set under Australian guidelines for animal welfare and experiments were subject to Monash University animal welfare ethics review (Approval #MARP/2019/13606).