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Biochem Biophys Res Commun ; 553: 25-29, 2021 05 14.
Article in English | MEDLINE | ID: covidwho-1147359


The current COVID-19 pandemic is caused by infections with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A sex-bias has been observed, with increased susceptibility and mortality in male compared to female patients. The gene for the SARS-CoV-2 receptor ACE2 is located on the X chromosome. We previously generated TP53 mutant pigs that exhibit a sex-specific patho-phenotype due to altered regulation of numerous X chromosome genes. In this study, we explored the effect of p53 deficiency on ACE2 expression in pigs. First, we identified the p53 binding site in the ACE2 promoter and could show its regulatory effect on ACE2 expression by luciferase assay in porcine primary kidney fibroblast cells. Later, quantitative PCR and western blot showed tissue- and gender-specific expression changes of ACE2 and its truncated isoform in p53-deficient pigs. We believe these findings will broaden the knowledge on ACE2 regulation and COVID-19 susceptibility.

Angiotensin-Converting Enzyme 2/metabolism , Gene Expression Regulation , Organ Specificity , Sex Characteristics , Sus scrofa/metabolism , Tumor Suppressor Protein p53/metabolism , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/genetics , Animals , Base Sequence , Binding Sites , COVID-19/metabolism , COVID-19/virology , Disease Models, Animal , Female , Fibroblasts , Gene Deletion , Male , Promoter Regions, Genetic/genetics , Tumor Suppressor Protein p53/deficiency , Tumor Suppressor Protein p53/genetics , X Chromosome/genetics
Int Immunopharmacol ; 92: 107365, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-1014567


Emerging beta-coronaviruses (ß-CoVs), including Severe Acute Respiratory Syndrome CoV-1 (SARS-CoV-1), Middle East Respiratory Syndrome-CoV (MERS-CoV), and Severe Acute Respiratory Syndrome CoV-2 (SARS-CoV-2, the cause of COVID19) are responsible for acute respiratory illnesses in human. The epidemiological features of the SARS, MERS, and new COVID-19 have revealed sex-dependent variations in the infection, frequency, treatment, and fatality rates of these syndromes. Females are likely less susceptible to viral infections, perhaps due to their steroid hormone levels, the impact of X-linked genes, and the sex-based immune responses. Although mostly inactive, the X chromosome makes the female's immune system more robust. The extra immune-regulatory genes of the X chromosome are associated with lower levels of viral load and decreased infection rate. Moreover, a higher titer of the antibodies and their longer blood circulation half-life are involved in a more durable immune protection in females. The activation rate of the immune cells and the production of TLR7 and IFN are more prominent in females. Although the bi-allelic expression of the immune regulatory genes can sometimes lead to autoimmune reactions, the higher titer of TLR7 in females is further associated with a stronger anti-viral immune response. Considering these sex-related differences and the similarities between the SARS, MERS, and COVID-19, we will discuss them in immune responses against the ß-CoVs-associated syndromes. We aim to provide information on sex-based disease susceptibility and response. A better understanding of the evasion strategies of pathogens and the host immune responses can provide worthful insights into immunotherapy, and vaccine development approaches.

Betacoronavirus , Coronavirus Infections/immunology , Coronavirus Infections/virology , Respiratory Tract Infections/immunology , Respiratory Tract Infections/virology , Antiviral Agents/therapeutic use , Coronavirus Infections/drug therapy , Female , Humans , Male , Respiratory Tract Infections/drug therapy , Sex Factors
Cytokine Growth Factor Rev ; 58: 66-74, 2021 04.
Article in English | MEDLINE | ID: covidwho-838835


Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic, induces severe pneumonia mainly in elderly males. Epidemiological data clearly indicate sex-based differences in disease outcomes, with men accounting for about 70 % of deaths, despite similar susceptibility to infection. It is well known that females are endowed with higher capacity to produce antibodies, which correlates with viral clearance and disease resolution in the context of SARS-Cov-2 infection. Many X-linked immune genes escape X inactivation showing biallelic expression in female immune cells, particularly in plasmacytoid dendritic cells (pDCs). PDCs are more active in females and endowed with high capability to induce IFN-α-mediated B cell activation and differentiation into antibody-producing plasma cells throughout epigenetic mechanisms linked to trained immunity. Thus, we hypothesize that following SARS-CoV-2 infection, epigenetic modifications of X-linked genes involved in pDC-mediated type I IFN (IFN-I) signaling occurs more effectively in females, for inducing neutralizing antibody response as an immune correlate driving sex-biased disease outcome.

Antibody Formation , COVID-19/diagnosis , COVID-19/immunology , Interferon Type I/physiology , SARS-CoV-2/immunology , COVID-19/epidemiology , Female , Humans , Male , Pandemics , Prognosis , Sex Characteristics