Gasdermin-D activation by SARS-CoV-2 triggers NET and mediate COVID-19 immunopathology.

BACKGROUND: The release of neutrophil extracellular traps (NETs) is associated with inflammation, coagulopathy, and organ damage found in severe cases of COVID-19. However, the molecular mechanisms underlying the release of NETs in COVID-19 remain unclear. OBJECTIVES: We aim to investigate the role of the Gasdermin-D (GSDMD) pathway on NETs release and the development of organ damage during COVID-19. METHODS: We performed a single-cell transcriptome analysis in public data of bronchoalveolar lavage. Then, we enrolled 63 hospitalized patients with moderate and severe COVID-19. We analyze in blood and lung tissue samples the expression of GSDMD, presence of NETs, and signaling pathways upstreaming. Furthermore, we analyzed the treatment with disulfiram in a mouse model of SARS-CoV-2 infection. RESULTS: We found that the SARS-CoV-2 virus directly activates the pore-forming protein GSDMD that triggers NET production and organ damage in COVID-19. Single-cell transcriptome analysis revealed that the expression of GSDMD and inflammasome-related genes were increased in COVID-19 patients. High expression of active GSDMD associated with NETs structures was found in the lung tissue of COVID-19 patients. Furthermore, we showed that activation of GSDMD in neutrophils requires active caspase1/4 and live SARS-CoV-2, which infects neutrophils. In a mouse model of SARS-CoV-2 infection, the treatment with disulfiram inhibited NETs release and reduced organ damage. CONCLUSION: These results demonstrated that GSDMD-dependent NETosis plays a critical role in COVID-19 immunopathology and suggests GSDMD as a novel potential target for improving the COVID-19 therapeutic strategy.

Tadalafil treatment improves cardiac, renal and lower urinary tract dysfunctions in rats with heart failure.

Tadalafil, a phosphodiesterase-5 (PDE5) inhibitor, shown to exert a protection to heart failure (HF) associated damage or lower urinary tract symptoms (LUTS). Thus, we investigated the contribution of tadalafil chronic treatment in the alterations of LUTS in HF rats. Male rats were subjected to aortocaval fistula model for HF induction. Echocardiography, cystometric, renal function and redox cell balance, as well as concentration-response curves to carbachol, KCl, ATP and frequency-response curves to electrical field stimulation (EFS) were evaluated in Sham, HF, Tadalafil and HF-Tadalafil (12 weeks endpoint) groups. HF group to present increased in left-ventricle (LV) mass and in LV end-diastolic- and LV end-systolic volume, with a decreased ejection fraction. Tadalafil treatment was able to decrease in hypertrophy and improve the LV function restoring cardiac function. For micturition function (in vivo), HF animals shown an increase in basal pressure, threshold pressure, no-voiding contractions and decreased bladder capacity, being that the tadalafil treatment restored the cystometric parameters. Contractile mechanism response (in vitro) to carbachol, KCl, ATP and EFS in the detrusor muscles (DM) were increased in the HF group, when compared to Sham group. However, tadalafil treatment restored the DM hypercontractility in the HF animals. Moreover, renal function as well as the oxidative mechanism was impaired in the HF animals, and the tadalafil treatment improved all renal and oxidative parameters in HF group. Our data shown that tadalafil has potential as multi-therapeutic drug and may be used as a pharmacological strategy for the treatment of cardiovascular, renal and urinary dysfunctions associated with HF.

SARS-CoV-2 infects adipose tissue in a fat depot- and viral lineage-dependent manner.

Visceral adiposity is a risk factor for severe COVID-19, and a link between adipose tissue infection and disease progression has been proposed. Here we demonstrate that SARS-CoV-2 infects human adipose tissue and undergoes productive infection in fat cells. However, susceptibility to infection and the cellular response depends on the anatomical origin of the cells and the viral lineage. Visceral fat cells express more ACE2 and are more susceptible to SARS-CoV-2 infection than their subcutaneous counterparts. SARS-CoV-2 infection leads to inhibition of lipolysis in subcutaneous fat cells, while in visceral fat cells, it results in higher expression of pro-inflammatory cytokines. Viral load and cellular response are attenuated when visceral fat cells are infected with the SARS-CoV-2 gamma variant. A similar degree of cell death occurs 4-days after SARS-CoV-2 infection, regardless of the cell origin or viral lineage. Hence, SARS-CoV-2 infects human fat cells, replicating and altering cell function and viability in a depot- and viral lineage-dependent fashion.

Effects of glucosyl-hesperidin and physical training on body weight, plasma lipids, oxidative status and vascular reactivity of rats fed with high-fat diet.

OBJECTIVE: The aim of the study was to evaluate the effects of supplementation with glucosyl hesperidin (GH), with or without physical training, on body weight, fat depot, glucose and plasma lipids, oxidative status and vascular function of rats fed with high-fat diet (HFD). METHODS: After weaning, male Wistar rats were fed with an HFD plus fructose for 12 weeks and started receiving oral antioxidant supplementation and/or physical training after the fourth week of diet for eight further weeks. Body weight, epididymal and retroperitoneal fat, plasma glucose and lipids, oxidative status and mesenteric artery reactivity were evaluated. RESULTS: Rats fed with HFD presented higher body weight gain and fat accumulation compared to control rats, while GH supplementation did not influence these parameters. Physical training reduced the body weight gain and fat accumulation and modulated the oxidative status by increasing superoxide dismutase activity and total antioxidant capacity and reducing lipid peroxidation. GH alone decreased lipid peroxidation. However, when given to exercised rats, it impaired the response elicited by physical training. HFD caused endothelial dysfunction, and neither GH nor physical exercise prevented it. Potency of sodium nitroprusside was increased in exercised animals but not in GH-supplemented rats. CONCLUSION: Physical exercise partially decreased the body fat accumulation, decreased plasma levels of glucose and lipids and improved general oxidative status and endothelium-independent relaxation in mesenteric arteries of rats fed with HFD. GH exhibited benefits only in the oxidative status. However, GH given in association with physical exercise did not cause further changes in addition to those promoted by physical exercise. On the contrary, in exercised animals, GH prevented those changes elicited by physical training in plasma glucose and lipids, oxidative status and endothelium-independent relaxation.