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.

Increased Rho-kinase-mediated prostate contractions associated with impairment of ß-adrenergic-cAMP-signaling pathway by chronic nitric oxide deficiency.

Impairment of nitric oxide (NO) - cyclic GMP signaling pathway is likely to contribute to human begnin prostate hyperplasia (BPH). In the present study we have used a model of chronic NO synthesis inhibition to evaluate the functional alterations of prostate smooth muscle (PSM) machinery, and involvement of Rho-kinase pathway. Wistar rats were treated with the NO inhibitor N(ω)-nitro-l-arginine methyl ester (L-NAME, 20mg/kg/day; 4 weeks), after which contractile responses to phenylephrine (α1-adrenoceptor agonist; 1nM to 100µM), carbachol (muscarinic agonist; 1nM to 1mM) and α,ß-methylene ATP (P2X receptor agonist; 1-10µM), as well as to electrical-field stimulation (EFS; 1-32Hz) were evaluated. PSM relaxations to isoproterenol (non-selective ß-adrenoceptor agonist, 0.1nM to 10µM) and sodium nitroprusside (NO donor, 1nM to 10mM) were also evaluated. The ratio prostate weight/body weight was 22% greater (P<0.05) in L-NAME compared with control group. The PSM contractions to phenylephrine, carbachol and α,ß-methylene ATP were higher in L-NAME (Emax: 3.85±0.25, 3.52±0.35 and 2.03±0.2mN, respectively) compared with control group (Emax: 3.08±0.17, 2.37±0.18 and 1.57±0.18mN, respectively). The PSM contractions induced by EFS were also significantly greater in L-NAME group. Prior incubation with the Rho-kinase inhibitor Y27632 (1µM) fully reversed the enhanced contractions to phenylephrine and carbachol. Isoproterenol-induced PSM relaxations were 34% lower in L-NAME group, which was associated with reduced levels of cAMP in prostate tissue. The relaxations to sodium nitroprusside remained unaltered in L-NAME group. In summary, chronic NO deficiency leads to increased Rho-kinase-mediated PSM contractile responses accompanied by impairment of ß-adrenergic-cAMP-signaling pathway.

Urinary Bladder Dysfunction in Transgenic Sickle Cell Disease Mice.

BACKGROUND: Urological complications associated with sickle cell disease (SCD), include nocturia, enuresis, urinary infections and urinary incontinence. However, scientific evidence to ascertain the underlying cause of the lower urinary tract symptoms in SCD is lacking. OBJECTIVE: Thus, the aim of this study was to evaluate urinary function, in vivo and ex vivo, in the Berkeley SCD murine model (SS). METHODS: Urine output was measured in metabolic cage for both wild type and SS mice (25-30 g). Bladder strips and urethra rings were dissected free and mounted in organ baths. In isolated detrusor smooth muscle (DSM), relaxant response to mirabegron and isoproterenol (1nM-10µM) and contractile response to (carbachol (CCh; 1 nM-100µM), KCl (1 mM-300mM), CaCl2 (1µM-100mM), α,ß-methylene ATP (1, 3 and 10 µM) and electrical field stimulation (EFS; 1-32 Hz) were measured. Phenylephrine (Phe; 10nM-100µM) was used to evaluate the contraction mechanism in the urethra rings. Cystometry and histomorphometry were also performed in the urinary bladder. RESULTS: SS mice present a reduced urine output and incapacity to produce typical bladder contractions and bladder emptying (ex vivo), compared to control animals. In DSM, relaxation in response to a selective ß3-adrenergic agonist (mirabegron) and to a non-selective ß-adrenergic (isoproterenol) agonist were lower in SS mice. Additionally, carbachol, α, ß-methylene ATP, KCl, extracellular Ca2+ and electrical-field stimulation promoted smaller bladder contractions in SS group. Urethra contraction induced by phenylephrine was markedly reduced in SS mice. Histological analyses of SS mice bladder revealed severe structural abnormalities, such as reductions in detrusor thickness and bladder volume, and cell infiltration. CONCLUSIONS: Taken together, our data demonstrate, for the first time, that SS mice display features of urinary bladder dysfunction, leading to impairment in urinary continence, which may have an important role in the pathogenesis of the enuresis and infections observed the SCD patients.

Alterações fisiopatológicas em bexiga urinária de camundongos obesos resistentes à insulina / Physiopathological alterations in urinary bladder from insulin resistant obese mice

Obesidade/síndrome metabólica são fatores de risco para o desenvolvimento dos sintomas do trato urinário inferior (LUTS), incluindo hiperatividade de bexiga. Em nosso estudo visamos investigar a relação entre resistência à insulina e hiperatividade de bexiga em modelo de obesidade induzida por dieta hiperlipídica (10 semanas) em camundongos C57BL6/J. Curvas concentração-resposta a diferentes agentes contráteis e à insulina foram realizadas em bexigas isoladas de camundongos e humanos. Estudo cistométrico foi conduzido em camundongos anestesiados. Expressão protéica de PKC, canais de Ca2+ do tipo L, eNOS (Ser1177) e AKT (Ser473) fosforiladas, bem como de marcadores da resposta a proteínas mal dobradas (UPR), TRIB3, CHOP e ATF4, foi determinada por western blot. Camundongos obesos exibiram aumento do peso corpóreo, gordura epididimal, glicemia de jejum e resistência à insulina. As respostas contráteis aos diferentes agentes foram maiores nos animais obesos, o que foi normalizado pela pré-incubação com o bloqueador dos canais de Ca2+ do tipo L, amlodipino. Animais do grupo obeso apresentaram hiperatividade de bexiga, como demonstrado por estudo cistométrico. As curvas concentração-resposta ao agonista muscarínico, carbacol, foram dependentes da ativação da PKC. A resposta contrátil ao ativador da PKC, PDBu, foi abolida pela incubação com amlodipino. O tratamento com metformina melhorou a sensibilidade à insulina assim como normalizou a hipercontratilidade in vitro, a hiperatividade de bexiga e os níveis de PKC e pAKT em camundongos obesos. A insulina (1-100 nM) produziu relaxamento concentração-dependente em bexigas de camundongos e humanos, o que foi reduzido pela remoção da camada urotelial ou inibição da via de sinalização da PI3K/AKT/eNOS. Em condições fisiológicas, o estímulo com insulina resultou em um aumento de aproximadamente 3 vezes nos níveis de GMPc; porém, o relaxamento e os níveis de GMPc foram menores em bexigas de animais obesos...

Obesity/metabolic syndrome are common risk factors for lower urinary tract symptoms, including overactive bladder. This study aimed to investigate whether insulin resistance affects bladder function in a model of obesity induced by high-fat diet (10 weeks) in C57BL6/J mice. Concentration-response curves to contractile agents and insulin were performed in human and mouse bladders. Cystometric study was performed in terminally anaesthetized mice. Western blot was performed in bladders to detect PKC, Cav1.2, phosphorylated eNOS (Ser1177) and AKT (Ser473), as well as the unfolded protein response (UPR) markers TRIB3, CHOP and ATF4. Obese mice exhibited higher body weight, epididymal fat mass, fasting glucose and insulin resistance. All the contractile agents produced greater bladder contractions in obese mice, which were fully reversed by the Cav1.2 blocker amlodipine. Cystometry evidenced overactive bladder in obese group that were also prevented by amlodipine. Carbachol induced contractions was dependent on the PKC activation, and PKC expression was increased in obese mice. Metformin treatment improved the insulin sensitivity, normalized the in vitro bladder hypercontractility, cystometric dysfunction and restored PKC and pAKT expression in the obese bladders. Insulin (1-100 nM) produced concentration-dependent mouse and human bladder relaxations that were markedly reduced by mucosal removal or inhibition of the PI3K/AKT/eNOS pathway. In mouse bladders, insulin produced a 3.0-fold increase in cGMP levels (P<0.05), that was prevented by PI3K/AKT/eNOS pathway inhibition. PI3K inhibition abolished insulin-induced phosphorylation of AKT and eNOS in bladder mucosa. Obese mice showed greater voiding frequency and non-voiding contractions, indicating overactive bladder...