Wnt3a Facilitates SARS-CoV-2 Pseudovirus Entry into Cells.

How ACE2 functions as the major host receptor of SARS-CoV-2 despite having low expression in the lungs is still unknown. To facilitate the development of therapeutic strategies against coronaviruses, gaining a deeper comprehension of the molecular mechanism of SARS-CoV-2 infection is imperative. In our previous study, we identified several potential host factors of SARS-CoV-2 using an shRNA arrayed screen, one of which was Wnt3a. Here, we validated the significance of Wnt3a, a potent activator of the Wnt/ß-catenin signaling pathway, for SARS-CoV-2 entry into cells by evaluating the effects of its knockdown and overexpression on SARS-CoV-2 pseudotyped virus entry. Further analysis revealed that SARS-CoV-2 pseudotyped virus infection activates the canonical Wnt/ß-catenin signaling pathway, which we found could subsequently stimulate ACE2 transcription. Collectively, our study identified Wnt3a as an important host factor that facilitates ACE2-mediated virus infection. Insight into the virus entry mechanism is impactful as it will aid in developing novel therapeutic strategies against current and future coronavirus pandemics.

A disintegrin and metalloproteinase domain 9 facilitates SARS-CoV-2 entry into cells with low ACE2 expression.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of the Coronavirus disease-19 (COVID-19) pandemic, utilizes angiotensin-converting enzyme 2 (ACE2) as a receptor for virus infection. However, the expression pattern of ACE2 does not coincide with the tissue tropism of SARS-CoV-2, hinting that other host proteins might be involved in facilitating SARS-CoV-2 entry. To explore potential host factors for SARS-CoV-2 entry, we performed an arrayed shRNA screen in H1650 and HEK293T cells. Here, we identified a disintegrin and a metalloproteinase domain 9 (ADAM9) protein as an important host factor for SARS-CoV-2 entry. Our data showed that silencing ADAM9 reduced virus entry, while its overexpression promoted infection. The knockdown of ADAM9 decreased the infectivity of the variants of concern tested-B.1.1.7 (alpha), B.1.617.2 (delta), and B.1.1.529 (omicron). Furthermore, mechanistic studies indicated that ADAM9 is involved in the binding and endocytosis stages of SARS-CoV-2 entry. Through immunoprecipitation experiments, we demonstrated that ADAM9 binds to the S1 subunit of the SARS-CoV-2 Spike. Additionally, ADAM9 can interact with ACE2, and co-expression of both proteins markedly enhances virus infection. Moreover, the enzymatic activity of ADAM9 facilitates virus entry. Our study reveals an insight into the mechanism of SARS-CoV-2 virus entry and elucidates the role of ADAM9 in virus infection. IMPORTANCE COVID-19, an infectious respiratory disease caused by SARS-CoV-2, has greatly impacted global public health and the economy. Extensive vaccination efforts have been launched worldwide over the last couple of years. However, several variants of concern that reduce the efficacy of vaccines have kept emerging. Thereby, further understanding of the mechanism of SARS-CoV-2 entry is indispensable, which will allow the development of an effective antiviral strategy. Here, we identify a disintegrin and metalloproteinase domain 9 (ADAM9) protein as a co-factor of ACE2 important for SARS-CoV-2 entry, even for the variants of concern, and show that ADAM9 interacts with Spike to aid virus entry. This virus-host interaction could be exploited to develop novel therapeutics against COVID-19.

Functional assessments of SARS-CoV-2 single-round infectious particles with variant-specific spike proteins on infectivity, drug sensitivity, and antibody neutralization.

Working with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is restricted to biosafety level III (BSL-3) laboratory. The study used a trans-complementation system consisting of virus-like particles (VLPs) and DNA-launched replicons to generate SARS-CoV-2 single-round infectious particles (SRIPs) with variant-specific spike (S) proteins. S gene of Wuhan-Hu-1 strain (SWH1) or Omicron BA.1 variant (SBA.1), along with the envelope (E) and membrane (M) genes, were cloned into a tricistronic vector, co-expressed in the cells to produce variant-specific S-VLPs. Additionally, the replicon of the WH1-like strain without S, E, M and accessory genes, was engineered under the control by a CMV promoter to produce self-replicating RNAs within VLP-producing cells, led to create SWH1- and SBA.1-based SARS-CoV-2 SRIPs. The SBA.1-based SRIP showed lower virus yield, replication, N protein expression, fusogenicity, and infectivity compared to SWH1-based SRIPs. SBA.1-based SRIP also exhibited intermediate resistance to neutralizing antibodies produced by SWH1-based vaccines, but were effective at infecting cells with low ACE2 expression. Importantly, both S-based SRIPs responded similarly to remdesivir and GC376, with EC50 values ranging from 0.17 to 1.46 µM, respectively. The study demonstrated that this trans-complementation system is a reliable and efficient tool for generating SARS-CoV-2 SRIPs with variant-specific S proteins. SARS-CoV-2 SRIPs, mimicking authentic live viruses, facilitate comprehensive analysis of variant-specific virological characteristics, including antibody neutralization, and drug sensitivity in non-BSL-3 laboratories.

Association of depression and antidepressant therapy with antiretroviral therapy adherence and health-related quality of life in men who have sex with men.

UNAIDS' HIV treatment targets require that 90% of people living with HIV/AIDS (PLWHA) receiving antiretroviral treatment (ART) achieve viral suppression and 90% of people with viral suppression have good health-related quality of life (HRQOL). This study aimed to examine the association of depression and antidepressant therapy with ART adherence and HRQOL in HIV-infected men who have sex with men (MSM). From 2018 through 2020, HIV-infected MSMs were consecutively recruited (N = 565) for the evaluation of ART adherence and HRQOL at Taipei City Hospital HIV clinics. Non-adherence to ART was defined as a Medication Adherence Report Scale score of < 23. HRQOL in PLWHHA was evaluated using WHOQOL-BREF, Taiwan version. Overall, 14.0% had depression and 12.4% exhibited non-adherence to ART. The nonadherence proportion was 21.8% and 10.5% in depressed and nondepressed HIV-infected MSM, respectively. After adjusting for other covariates, depression was associated with a higher risk of nonadherence to ART (adjusted odds ratio = 2.02; 95% confidence interval: 1.02-4.00). Physical, psychological, social, and environmental HRQOL were significantly negatively associated with depression. Considering antidepressant therapy, ART nonadherence was significantly associated with depression without antidepressant therapy but not with antidepressant therapy. The depressed HIV-infected MSM without antidepressant therapy had worse psychological, social, and environmental HRQOL than those with antidepressant therapy. Our study suggests that depression is associated with poor ART adherence and HRQOL, particularly in those without antidepressant therapy. Adequate diagnosis and treatment of depression should be provided for PLWHA to improve their ART adherence and HRQOL.

Effects of Basic Amino Acids and Their Derivatives on SARS-CoV-2 and Influenza-A Virus Infection.

Amino acids have been implicated with virus infection and replication. Here, we demonstrate the effects of two basic amino acids, arginine and lysine, and their ester derivatives on infection of two enveloped viruses, SARS-CoV-2, and influenza A virus. We found that lysine and its ester derivative can efficiently block infection of both viruses in vitro. Furthermore, the arginine ester derivative caused a significant boost in virus infection. Studies on their mechanism of action revealed that the compounds potentially disturb virus uncoating rather than virus attachment and endosomal acidification. Our findings suggest that lysine supplementation and the reduction of arginine-rich food intake can be considered as prophylactic and therapeutic regimens against these viruses while also providing a paradigm for the development of broad-spectrum antivirals.

Methamphetamine Use Associated with Non-adherence to Antiretroviral Treatment in Men Who Have Sex with Men.

Methamphetamine is a prevalent recreational drug among men who have sex with men (MSM) living with HIV and could cause the cognitive impairment and memory loss. However, studies on the association between methamphetamine use and adherence to antiretroviral treatment (ART) are limited and had inconsistent findings. This study aimed to determine the impact of methamphetamine use on adherence to ART among MSM living with HIV. From December 2018 to October 2019, MSM living with HIV were recruited (N = 351) and non-adherence to ART was defined as a Medication Adherence Report Scale score of <23. Overall, 16.0% of the participants reported methamphetamine use in the prior three months and 13.4% of the participants had non-adherence to ART. The proportion of non-adherence to ART among HIV-positive MSM were 28.6% and 10.5% with and without methamphetamine use, respectively. After controlling for demographics, illicit drug use, and co-morbidities, methamphetamine use during the prior three months was associated with a higher risk of non-adherence to ART (adjusted odds ratio = 3.08; 95% confidence intervals: 1.24-7.69). Compared with HIV-positive MSM with non-adherence to ART, HIV-positive MSM with good adherence to ART had a higher CD4 counts and were more likely to achieve an undetectable viral load. Since poor adherence to ART is associated with an increased HIV viral load and the risk of HIV transmission to others, our study suggests that it is imperative to screen HIV-positive patients for methamphetamine use and to provide effective therapy to reduce methamphetamine use and the associated non-adherence to ART.