Background Acute respiratory distress syndrome (ARDS) is the primary cause of mortality in critically ill subjects infected with the novel coronavirus (severe acute respiratory syndrome‐coronavirus‐2, or SARS‐CoV‐2). Given the elevated levels of circulating proinflammatory cytokines such as tumor necrosis factors (TNF)‐⍺ and interleukin (IL)‐6, it has been postulated that a “cytokine storm” is responsible for the COVID‐19 ARDS. A critical step in cytokine signaling is the shedding of membrane‐anchored cytokines and their receptors. Objective To determine the role of the metalloprotease/shreddase ADAM‐17 (A disinterring and metalloproteinase 17) in COVID‐19‐ mediated cytokine release from lung epithelial cells. We hypothesized pharmacological inhibition of ADAM‐17 attenuated COVID‐19‐induced release of TNF‐α in lung epithelial cells. Materials and Methods Human primary bronchial/tracheal epithelial cells (ATCC®, PS‐300‐010) were cultured to sub‐confluence and challenged with COVID‐19 Spike Coronavirus pseudovirus (SARS‐COV‐2 pseudo‐virus, MyBioSource), and phorbol‐12‐myristate‐13‐acetate (PMA, Sigma), which was used as a positive control in the presence or absence of the ADAM‐17 inhibitor TNF‐α Protease Inhibitor‐0 (TAPI‐0, Sigma). TNF‐α levels were determined in the cell media at different time points (2‐12h) following the challenge using an ELISA assay. Data are represented as mean ± SEM, and statistical significance was determined by using the Student’s t‐test. Results Treatment with both PMA (0.1 µM) and SARS‐COV‐2 pseudovirus (1x108pseudoviral particles), resulted in a robust increase of TNF‐α in the culture media 8 h post‐stimulation (3243.75± 55.3 and 1278.6 ± 357 pg/mL respectively, p <0.05, n = 4). Furthermore, treatment with TAPI‐0 resulted in a concentration‐dependent inhibition of the pseudovirus‐induced TNF‐α release by cultured bronchial epithelial cells, with a complete inhibition observed at 100 µM of TAPI‐0. Conclusion Targeting ADAM‐17 is a potential strategy to mitigated the cytokine storm associated with COVID‐19‐ARDS.

ID 50581 Poster Board 496Background and Aim: Obesity is growing at epidemic proportions and is an independent risk factor for diabetes and cardiovascular disease. A paucity of safe and effective anti-obesity drugs and nutraceuticals have been explored to prevent weight gain. The root of the balloon flower Platycodon grandiflorus (Jacquin) (PG) has been used in traditional medicine. A recent report indicates that its root extract reduces body weight and facilitates thermogenesis. The objective of this study was to evaluate the efficacy of PG in attenuating weight gain and insulin resistance in a mouse model of diet-induced obesity.Methods: Five-week-old male C57BL/6J mice were randomly assigned to receive a normal diet group (ND) (10 kcal% fat), or a high-fat-diet (HFD) (60 kcal% fat), with or without 1.025 ppm PG (HFD+PG) (n=8/per group) for a period of twelve weeks. Animal weight and food intake were assessed weekly during the treatment period. In the last week of treatment, glucose tolerance was assessed by an intra-peritoneal glucose tolerance test (IPGTT), and body composition (fat mass and lean body mass) was assessed by dual x-ray absorptiometry (DEXA). Hepatic liver accumulation was assessed via H&E stain with image J analysis. Data are expressed as mean ± S.E.M and statistically evaluated using analysis of variance followed by Tukey's multiple comparisons.Results: Thirteen weeks of treatment with HFD induced weight gain (p <0.0001) compared to ND animals (47.0 ± 1.72 g vs. 28.4 g ± 1.74g), which was attenuated by HFD + PG supplementation (43.0 ± 3.8 g; p <0.0001). Compared to ND animals, fat accumulation in the liver was significantly increased following HFD-feeding (p <0.01), which was blunted in mice that received HFD + PG by 78,5% (p <0.05). In contrast, PG supplementation did not alter food intake, IPGTT, or DEXA outcomes (p $0.05).Conclusion: Supplementation with P. grandifloras attenuates weight gain and hepatic steatosis in a dietary mouse model of obesity.