Strategies to target SARS-CoV-2 entry and infection using dual mechanisms of inhibition by acidification inhibitors

Many viruses utilize the host endo-lysosomal network for infection. Tracing the endocytic itinerary of SARS-CoV-2 can provide insights into viral trafficking and aid in designing new therapeutic strategies. Here, we demonstrate that the receptor binding domain (RBD) of SARS-CoV-2 spike protein is internalized via the pH-dependent CLIC/GEEC (CG) endocytic pathway in human gastric-adenocarcinoma (AGS) cells expressing undetectable levels of ACE2. Ectopic expression of ACE2 (AGS-ACE2) results in RBD traffic via both CG and clathrin-mediated endocytosis. Endosomal acidification inhibitors like BafilomycinA1 and NH4Cl, which inhibit the CG pathway, reduce the uptake of RBD and impede Spike-pseudoviral infection in both AGS and AGS-ACE2 cells. The inhibition by BafilomycinA1 was found to be distinct from Chloroquine which neither affects RBD uptake nor alters endosomal pH, yet attenuates Spike-pseudovirus entry. By screening a subset of FDA-approved inhibitors for functionality similar to BafilomycinA1, we identified Niclosamide as a SARS-CoV-2 entry inhibitor. Further validation using a clinical isolate of SARS-CoV-2 in AGS-ACE2 and Vero cells confirmed its antiviral effect. We propose that Niclosamide, and other drugs which neutralize endosomal pH as well as inhibit the endocytic uptake, could provide broader applicability in subverting infection of viruses entering host cells via a pH-dependent endocytic pathway.

Missed Elevated Blood Pressure in Triaged Outpatients: A Preliminary Cross-Sectional Multicentre Study in Northern Nigeria

BACKGROUND

Hypertension is a common medical condition but largely undiagnosed, untreated, poorly controlled, and undertreated in low- and middle-income countries. Studies have reported missed hypertension during triage in Emergency Departments; however, little is known about missed elevated blood pressure (EBP) during triage in primary care settings. This study assessed the prevalence and predictors of missed EBP among triaged patients attending General Outpatient Clinics in Northern Nigeria.

METHODS

This was a descriptive cross-sectional multi-centre study involving 187 adults randomly selected from patients triaged in four General Outpatient Clinics in northern Nigeria. An investigator-administered questionnaire was employed to obtain data regarding participants' socio-demographic, triage blood pressure (BP) measurement, physician-led BP measurement, and physicians' clinical decision characteristics. Chi-square test and logistic regression analysis were used to determine factors associated with and predictors of missed EBP, respectively.

RESULTS

Participants' mean age was 40.6±14.7years. They were predominantly females (122, 65.2%). EBP was missed in 28 (15%) participants at the triage. Participants' age (>40years) (Odds ratio [OR]=3.82, 95% Confidence interval [CI]=1.43-10.22, P=0.008), study site (OR=0.32, 95% CI=0.12-0.82, P=0.018) and perceived receipt of explanation on BP measurement procedure (OR=2.97, 95% CI=1.25-7.07, P=0.014) were predictors of missed EBP among participants.

CONCLUSION

The prevalence of missed EBP was low but remarkable because of its huge public health implications. Age, study site, perceived receipt of explanation on BP measurement procedure predicted missed EBP. Effective interventions are needed to curtail missed EBP in these and similar settings.

Purification of Plasmodium and Babesia- infected erythrocytes using a non-woven fabric filter

The purification of parasite-infected erythrocytes from whole blood containing leucocytes is crucial for many downstream genetic and molecular assays in parasitology. Current methodologies to achieve this are often costly and time consuming. Here, we demonstrate the successful application of a cheap and simple Non-Woven Fabric (NWF) filter for the purification of parasitized red blood cells from whole blood. NWF filtration was applied to the malaria-parasitized blood of three strains of mice, and one strain of rat, and to Babesia gibsoni parasitized dog blood. Before and after filtration, the white blood cell (WBC) removal rates and red blood cell (RBC) recovery rates were measured. After NWF filter treatment of rodent malaria-infected blood, the WBC removal rates and RBC recovery rates were, for Kunming mice: 99.51%±0.30% and 86.12%±8.37%; for BALB/C mice: 99.61%±0.15% and 80.74%±7.11%; for C57 mice: 99.71%±0.12% and 84.87%±3.83%; for Sprague-Dawley rats: 99.93%±0.03% and 83.30%±2.96%. Microscopy showed WBCs were efficiently removed from infected dog blood samples, and there was no obvious morphological change of B. gibsoni parasites. NWF filters efficiently remove leukocytes from malaria parasite-infected mouse and rat blood, and are also suitable for filtration of B. gibsoni-infected dog blood.