Acs Chem Neurosci
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The COVID-19 pandemic caused by SARS-CoV-2 represents a global public health emergency. The entry of SARS-CoV-2 into host cells requires the activation of its spike protein by host cell proteases. The serine protease, TMPRSS2, and cysteine proteases, Cathepsins B/L, activate spike protein and enable SARS-CoV-2 entry to the host cell through two completely different and independent pathways. ⋯ The molecular docking and MD simulation results showed strong and stable binding of cyclosporine A (CsA) with TMPRSS2 and CTSL genes. The above results indicate cyclosporine as a potential drug molecule, as apart from interacting with SARS-CoV-2 entry receptors, it also interacts with most of SARS-CoV-2 target host genes; thus it could potentially interfere with functions of SARS-CoV-2 proteins in human cells. We here also suggest that these antiviral drugs alone or in combination can simultaneously target both the entry pathways and thus can be considered as a potential treatment option for COVID-19.
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Several lines of evidence suggest the role of air-conditioning systems in the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Furthermore, the likelihood of novel coronavirus to take refuge inside a microbial Trojan horse, that is, Acanthamoeba, can further enhance possibility of SARS-CoV-2 transmission in the environment. Here we propose the use of various disinfection strategies that can be employed using filters with antimicrobial fabricated surfaces or using UV irradiation to achieve germicidal properties for removal of pathogenic microbes such as SARS-CoV-2 and amoebae in the ventilation systems.
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Observational Study
Taste and Smell Disorders in COVID-19 Patients: Role of Interleukin-6.
The rapid recovery of smell and taste functions in COVID-19 patients could be attributed to a decrease in interleukin-6 levels rather than central nervous system ischemic injury or viral damage to neuronal cells. To correlate interleukin-6 levels in COVID-19 patients with olfactory or gustatory dysfunctions and to investigate the role of IL-6 in the onset of these disorders, this observational study investigated 67 COVID-19 patients with taste or smell disorders or both, who did not require intensive care admission, admitted at COVID Hospital of Policlinico of Bari from March to May 2020. Interleukin-6 was assayed in COVID-19 patients with taste or smell disturbances at the time of admission and at the time of swab negativization. ⋯ Interleukin-6 levels in COVID-19 patients in relation to olfactory or gustatory disorders were correlated from the time of their admission to the time of swab negativization. Statistically significant correlations were obtained between the decrease of interleukin-6 levels and the improvement of smell (p value < 0.05) and taste (p = 0.047) functions at swab negativization. The acquired results demonstrate the key role of interleukin-6 in the pathogenesis of chemosensitive disorders in COVID-19 patients.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been established as a cause of severe alveolar damage and pneumonia in patients with advanced Coronavirus disease (COVID-19). The consolidation of lung parenchyma precipitates the alterations in blood gases in COVID-19 patients that are known to complicate and cause hypoxemic respiratory failure. With SARS-CoV-2 damaging multiple organs in COVID-19, including the central nervous system that regulates the breathing process, it is a daunting task to compute the extent to which the failure of the central regulation of the breathing process contributes to the mortality of COVID-19 affected patients. ⋯ Though a complex metabolic and respiratory dysregulation also occurs with infections caused by SARS-CoV-1 and MERS that are known to contribute toward deaths of the patients in the past, we highlight here the role of systemic dysregulation and the CNS respiratory regulation mechanisms in the causation of mortalities seen in COVID-19. The invasion of the CNS by SARS-CoV-2, as shown recently in areas like the brainstem that control the normal breathing process with nuclei like the pre-Bötzinger complex (pre-BÖTC), may explain why some of the patients with COVID-19, who have been reported to have recovered from pneumonia, could not be weaned from invasive mechanical ventilation and the occurrences of acute respiratory arrests seen in COVID-19. This debate is important for many reasons, one of which is the fact that permanent damage to the medullary respiratory centers by SARS-CoV-2 would not benefit from mechanical ventilators, as is possibly occurring during the management of COVID-19 patients.
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Spike protein (S protein) is the virus "key" to infect cells and is able to strongly bind to the human angiotensin-converting enzyme2 (ACE2), as has been reported. In fact, Spike structure and function is known to be highly important for cell infection as well as for entering the brain. Growing evidence indicates that different types of coronaviruses not only affect the respiratory system, but they might also invade the central nervous system (CNS). ⋯ In addition, we found that the SARS-CoV-2 S protein is slightly more positively charged than that of SARS-CoV since it contains four more positively charged residues and five less negatively charged residues which may lead to an increased affinity to bind to negatively charged regions of other molecules through nonspecific and specific interactions. Analysis the S protein binding to the host ACE2 receptor showed a 30% higher binding energy for SARS-CoV-2 than for the SARS-CoV S protein. These results might be useful for understanding the mechanism of cell entry, blood-brain barrier crossing, and clinical features related to the CNS infection by SARS-CoV-2.