Drugs that inhibit TMEM16 proteins block SARS-CoV-2 spike-induced syncytia.

COVID-19 is a disease with unique characteristics that include lung thrombosis1, frequent diarrhoea2, abnormal activation of the inflammatory response3 and rapid deterioration of lung function consistent with alveolar oedema4. The pathological substrate for these findings remains unknown. Here we show that the lungs of patients with COVID-19 contain infected pneumocytes with abnormal morphology and frequent multinucleation. The generation of these syncytia results from activation of the SARS-CoV-2 spike protein at the cell plasma membrane level. On the basis of these observations, we performed two high-content microscopy-based screenings with more than 3,000 approved drugs to search for inhibitors of spike-driven syncytia. We converged on the identification of 83 drugs that inhibited spike-mediated cell fusion, several of which belonged to defined pharmacological classes. We focused our attention on effective drugs that also protected against virus replication and associated cytopathicity. One of the most effective molecules was the antihelminthic drug niclosamide, which markedly blunted calcium oscillations and membrane conductance in spike-expressing cells by suppressing the activity of TMEM16F (also known as anoctamin 6), a calcium-activated ion channel and scramblase that is responsible for exposure of phosphatidylserine on the cell surface. These findings suggest a potential mechanism for COVID-19 disease pathogenesis and support the repurposing of niclosamide for therapy.

Blue laser light inhibits biofilm formation in vitro and in vivo by inducing oxidative stress.

Resolution of bacterial infections is often hampered by both resistance to conventional antibiotic therapy and hiding of bacterial cells inside biofilms, warranting the development of innovative therapeutic strategies. Here, we report the efficacy of blue laser light in eradicating Pseudomonas aeruginosa cells, grown in planktonic state, agar plates and mature biofilms, both in vitro and in vivo, with minimal toxicity to mammalian cells and tissues. Results obtained using knock-out mutants point to oxidative stress as a relevant mechanism by which blue laser light exerts its anti-microbial effect. Finally, the therapeutic potential is confirmed in a mouse model of skin wound infection. Collectively, these data set blue laser phototherapy as an innovative approach to inhibit bacterial growth and biofilm formation, and thus as a realistic treatment option for superinfected wounds.

Identification of protein disulfide isomerase as a cardiomyocyte survival factor in ischemic cardiomyopathy.

OBJECTIVES: The aim of the study was to analyze the molecular mechanisms activated during postinfarction remodeling in human hearts. BACKGROUND: The molecular mechanisms of initial response to ischemic insult in the heart and the pathways involved in compensation and remodeling are still largely unknown. METHODS: Up-regulation or down-regulation of gene expression in the human viable peri-infarct (vs. remote) myocardial region was investigated by complementary deoxyribonucleic acid array technology and confirmed at a single-gene/protein level with reverse transcriptase polymerase chain reaction and immunohistochemistry. An in vitro model of cardiomyocyte hypoxia in HL1 cells was used to validate anti-apoptotic effects of the candidate gene/protein and to assess the associated downstream cascade. Finally, a mouse model of myocardial infarction was used to test the in vivo effects of exogenous transfection with the candidate gene/protein. RESULTS: Protein disulfide isomerase (PDI), a member of the unfolded protein response, is 3-fold up-regulated in the viable peri-infarct myocardial region, and in a postmortem model, its expression is significantly inversely correlated with apoptotic rate and with presence of heart failure (HF) and biventricular dilatation. Induced PDI expression in HL1 cells conferred protection from hypoxia-induced apoptosis. Adenoviral-mediated PDI gene transfer to the mouse heart resulted in 2.5-fold smaller infarct size, significantly reduced cardiomyocyte apoptosis in the peri-infarct region, and smaller left ventricular end-diastolic diameter versus mice treated with a transgene-null adenoviral vector. CONCLUSIONS: These results suggest that PDI promotes survival after ischemic damage and that zinc-superoxide dismutase is one of the PDI molecular targets. Pharmacological modulation of this pathway might prove useful for future prevention and treatment of HF.