(T1070) PRE-CLINICAL IN VITRO EFFICACY OF ENGINEERED MESENCHYMAL STEM/STROMAL CELLS EXPRESSING SOLUBLE ACE2 DECOYS FOR ELIMINATION OF SARS-CoV-2 INFECTION
Ms. Univ Putra Malaysia University Putra Malaysia, Selangor, Malaysia
Abstract: The emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its continuously evolving variants has underscored the urgent need for innovative therapeutics to combat severe disease progression. In certain patients, COVID-19 advances to acute respiratory distress syndrome (ARDS), driven by a life-threatening hyper-inflammatory response and multi-organ failure. Mesenchymal stem cell (MSC)-based therapy have shown promising effects in reducing disease severity in ARDS patients and represent a potentially effective option against severe COVID-19. Whilst a variety of strategies have emerged to optimize MSC-based therapies, genetically modified MSCs for ARDS treatment has emerged as a compelling approach. Our strategy focuses on enhancing the umbilical-cord MSCs (UC-MSCs) by co-expressing various soluble angiotensin converting enzyme 2 (sACE2) decoy receptors and interleukin-37 (IL37). These modifications aim to mitigate the viral infection and attenuate the inflammatory response. In this study, we engineered UC-MSCs by transducing with three variants of sACE2 protein, {sACE2-WT (Wild-type), sACE2-WT-IgG1-Fc and sACE2-v.2.4-IgG}, and further co-transduced them with IL37. Using assays to evaluate protein expression, cell infectivity, and virus neutralization, we investigated the efficacy of UC-MSCs expressing all types of soluble ACE2 to target and destroy the aggressive SARS-CoV-2 Delta variant (B.1.612.2) pseudovirus infection. Upon infection, Calu3 and Caco2 cells exhibited 73.1% and 67.2% infection rates whereas all engineered MSCs displayed negligible infection. Further, in cell-based pseudovirus neutralization assays, indirect co-culture of Calu3 with all engineered MSC-sACE2-IL37 achieved 82.6%, 85.9%, and 90.1% neutralization after 72 hours, while direct co-culture yielded higher rates of 90.3%, 92%, and 93.4%, compared to 50% and 55% in control groups. Comparing the neutralization activities among the three MSC-sACE2-IL37 variants, MSC-sACE2-v.2.4-IgG-IL37 demonstrated robust and consistent neutralization activity, underscoring its superior ability to suppress pseudovirus transduction. Our results highlight the potential of engineered MSC-sACE2-IL37 as an innovative therapeutic strategy for combating severe SARS-CoV-2 infection.
