Neutrophil Elastase decreases SARS-CoV-2 Spike protein binding to human bronchial epithelia by clipping ACE-2 ectodomian from the epithelial surface

Patients with cystic fibrosis (CF) have decreased severity of SARS-CoV-2 infections, but the underlying cause is unknown. Patients with CF have high levels of neutrophil elastase (NE) in the airway. We examined whether respiratory epithelial angiotensin converting enzyme 2 (ACE-2), the receptor for the SARS-CoV-2 spike protein, is a proteolytic target of NE. Soluble ACE-2 (sACE-2) levels were quantified by ELISA in airway secretions and serum from patients with and without CF, and the association between sACE-2 levels and NE activity levels was evaluated in CF sputum. We determined that NE activity was directly correlated with increased ACE-2 in CF sputum. Additionally, primary human bronchial epithelial (HBE) cells, exposed to NE or control vehicle, were evaluated by western analysis for the release of cleaved ACE-2 ectodomain fragment into conditioned media, and by flow cytometry for the loss of cell surface ACE-2, its impact on SARS-CoV-2 spike protein binding. We found that NE treatment released ACE-2 ectodomain fragment from HBE and decreased spike protein binding to HBE. Furthermore, we performed NE treatment of recombinant ACE-2-Fc tagged protein in vitro to assess whether NE was sufficient to cleave recombinant ACE-2-Fc protein. Proteomic analysis identified, specific NE cleavage sites in the ACE-2 ectodomain that would result in loss of the putative N-terminal spike binding domain. Collectively, data support that NE plays a disruptive role in SARS-CoV-2 infection by catalyzing ACE-2 ectodomain shedding from the airway epithelia. This mechanism may reduce SARS-CoV-2 virus binding to respiratory epithelial cells and decrease severity of COVID19 infection.

ANALYSES OF SOME CALL FACTORS AFFECTING SAR LEVELS OF GSM MOBILE PHONES USED IN GHANA

In response to mounting radiofrequency health concerns, this study was constituted to provide critical scientific data and assess any potential exposure from global system for mobile communication mobile phones. Specific absorption rate (SAR) from phones approved by the regulator and untested/unapproved phones were measured with a ComoSAR system. The maximum 10 g SAR (0.51 W/kg) and 1 g SAR (0.99 W/kg) measured were 25 and 62% of the International Commission on Non-Ionizing Radiation Protection and Federal Communication Commission limits, respectively. The approved phone produced statistically significant higher SAR values relative to the untested phone. SAR values of the right ear were relatively higher. All maximum SAR values were recorded on the right ear. The regulatory approval status of the phone, phone's orientation to the head, operating frequency channel and in which ear (right or left) the phone is used influenced the SAR measured. The SAR values of the approved phone compared favourably with similar studies while the unapproved phone does not.

Assessment of levels of occupational exposure to workers in radiofrequency fields of two television stations in Accra, Ghana

A survey of the radiofrequency (RF) radiation was undertaken within the premises of two television (TV) stations, TVA and TVB, in Accra, Ghana. The primary objective of this study was to determine the level of RF exposure to workers in the TV stations. A spectrum analyser, a bi-conical antenna (30-300 MHz) and a log-periodic antenna (200 MHz-2.0 GHz) were used. Results obtained indicated that the wideband electric field strength levels recorded in this work vary between 0.006 and 58.5 V m(-1) at TVA and between 0.007 and 28.5 V m(-1) at TVB. Compared with the results from TVB, TVA recorded relatively higher values in the 30-400 MHz range, whereas TVB produced relatively higher values in the 400 MHz-1.7 GHz range. Generally, results obtained were found to be below the occupational reference levels of the International Commission on Non-Ionizing Radiation Protection, but at some locations, the field intensity was 4.3 times higher than the reference levels for the general public.

Regulation of neuronal and glial proteins by leptin: implications for brain development

The complete absence of leptin causes severe obesity in mice and humans, but its physiological roles are incompletely defined. Earlier studies reported decreased brain weight and impaired myelination in ob/ob and db/db mice. Here we have examined the effects of leptin deficiency and postnatal leptin treatment on brain weight, the expression of a broad array of neuronal and glial markers, and locomotor activity. ob/ob and db/db mice have reduced brain weight and an immature pattern of expression of synaptic and glial proteins, with growth-associated protein being elevated in the neocortex and hippocampus, and syntaxin-1, synaptosomal-associated protein-25, and synaptobrevin being decreased. The expression of myelin basic protein, proteolipid protein, and glial fibrillary acidic protein was also decreased in the neocortex, hippocampus, and striatum of ob/ob and db/db mice. Six weeks of leptin treatment initiated at week 4 increased brain weight and protein content, increased locomotor activity, and normalized levels of growth-associated protein, syntaxin-1, and synaptosomal-associated protein-25 in ob/ob mice without affecting synaptobrevin and glial proteins. In contrast with ob/ob and db/db mice, obese agouti (AY/a) mice had normal brain weight and expression of synaptic and glial proteins. These findings suggest that leptin, a peripheral signal of energy stores in adult animals, is required for normal neuronal and glial maturation in the mouse nervous system.