No abstract

It has been shown that eNOS uncoupling occurs in hypertension and atherosclerosis. However its causal role in vascular pathogenesis has not been previously characterized. Here, we challenged eNOS pre-uncoupled hph-1 mice (deficient in eNOS cofactor tetrahydrobiopterin biosynthetic enzyme GTPCHI) with Ang II (0.7 mg/kg/day, 14 days). Both wild-type (WT) and hph-1 groups developed hypertension similarly up to day 6 to 7. Thereafter approximately 14% of Ang II-infused (0.7 mg/kg/day) hph-1 mice (n=72) started to die suddenly of ruptured AAA. Among the survivors, 65% developed AAA, resulting in a total morbidity rate of 79%. In contrast, none of the Ang II-infused WT mice died or developed AAA. Ang II progressively deteriorated eNOS uncoupling in hph-1 mice, while augmenting H4B and nitric oxide (NO•) deficiencies. The abundance of the H4B salvage enzyme dihydrofolate reductase (DHFR) in the endothelium was decreased in hph-1 mice and further diminished by Ang II infusion. Intriguingly, restoration of DHFR expression by oral administration of folic acid (FA), or overexpression of DHFR, completely prevented AAA formation in Ang II-infused hph-1 mice while attenuating progressive uncoupling of eNOS. Folic acid also attenuated vascular remodelling and inflammation characterized by medial elastin break down, augmented MMP2 activity and activation of MMP9, as well as macrophage infiltration. In conclusion, these data innovatively suggest a causal role of eNOS uncoupling/H4B deficiency in AAA formation. Therefore oral FA administration, endothelium targeted DHFR gene therapy, and perhaps other countermeasures directed against eNOS uncoupling, could be used as new therapeutics for AAA.

SARS-CoV-2 variants continue to emerge during the global pandemic and may facilitate escape from current antibody therapies and vaccine protection. Here, we showed that the South African variant B.1.351 was the most resistant to current monoclonal antibodies and convalescent plasma from COVID-19-infected individuals, followed by the Brazilian variant P.1 and the UK variant B.1.1.7. This resistance hierarchy corresponded with Y144del and 242-244del mutations in the N-terminal domain and K417N/T, E484K and N501Y mutations in the receptor binding domain (RBD) of SARS-CoV-2. Crystal structural analysis of B.1.351 triple mutant (417N-484K-501Y) RBD complexed with monoclonal antibody P2C-1F11 revealed the molecular basis for antibody neutralization and escape. B.1.351 and P.1 also acquired the ability to use mouse and mink ACE2 receptor for entry. Our results demonstrate major antigenic shifts and potential broadening of the host range for B.1.351 and P.1 variants, which pose serious challenges to our current antibody therapies and vaccine protection.

No abstract

The prevalence of NAFLD is lower than the estimates from developed countries. But it still reaches the epidemic proportions, and its prevalence is increasing. Meanwhile, a nationwide prevalence investigation should be conducted to confirm the estimates and determine more accurate rates for specific populations.

To monitor severe acute respiratory syndrome (SARS) infection, a coronavirus protein microarray that harbors proteins from SARS coronavirus (SARS-CoV) and five additional coronaviruses was constructed. These microarrays were used to screen Ϸ400 Canadian sera from the SARS outbreak, including samples from confirmed SARS-CoV cases, respiratory illness patients, and healthcare professionals. A computer algorithm that uses multiple classifiers to predict samples from SARS patients was developed and used to predict 206 sera from Chinese fever patients. The test assigned patients into two distinct groups: those with antibodies to SARSCoV and those without. The microarray also identified patients with sera reactive against other coronavirus proteins. Our results correlated well with an indirect immunofluorescence test and demonstrated that viral infection can be monitored for many months after infection. We show that protein microarrays can serve as a rapid, sensitive, and simple tool for large-scale identification of viral-specific antibodies in sera.infectious disease ͉ protein chip ͉ virus diagnostics

Understanding the mechanism for antibody neutralization of SARS-CoV-2 is critical for the development of effective therapeutics and vaccines. We recently isolated a large number of monoclonal antibodies from SARS-CoV-2 infected individuals. Here we select the top three most potent yet variable neutralizing antibodies for in-depth structural and functional analyses. Crystal structural comparisons reveal differences in the angles of approach to the receptor binding domain (RBD), the size of the buried surface areas, and the key binding residues on the RBD of the viral spike glycoprotein. One antibody, P2C-1F11, most closely mimics binding of receptor ACE2, displays the most potent neutralizing activity in vitro and conferred strong protection against SARS-CoV-2 infection in Ad5-hACE2-sensitized mice. It also occupies the largest binding surface and demonstrates the highest binding affinity to RBD. More interestingly, P2C-1F11 triggers rapid and extensive shedding of S1 from the cell-surface expressed spike glycoprotein, with only minimal such effect by the remaining two antibodies. These results offer a structural and functional basis for potent neutralization via disruption of the very first and critical steps for SARS-CoV-2 cell entry.

SUMMARYThis work aims at identifying and quantifying uncertainties from various sources in human cardiovascular system based on stochastic simulation of a one dimensional arterial network. A general analysis of different uncertainties and probability characterization with log-normal distribution of these uncertainties is introduced. Deriving from a deterministic one dimensional fluid structure interaction model, we establish the stochastic model as a coupled hyperbolic system incorporated with parametric uncertainties to describe the blood flow and pressure wave propagation in the arterial network. By applying a stochastic collocation method with sparse grid technique, we study systemically the statistics and sensitivity of the solution with respect to many different uncertainties in a relatively complete arterial network with potential physiological and pathological implications for the first time.