The binding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein to its cellular receptor, the angiotensin-converting enzyme 2 (ACE2), causes its downregulation, ...which subsequently leads to the dysregulation of the renin-angiotensin system (RAS) in favor of the ACE-angiotensin II (Ang II)-angiotensin II type I receptor (AT1R) axis. AT1R has a major role in RAS by being involved in several physiological events including blood pressure control and electrolyte balance. Following SARS-CoV-2 infection, pathogenic episodes generated by the vasoconstriction, proinflammatory, profibrotic, and prooxidative consequences of the Ang II-AT1R axis activation are accompanied by a hyperinflammatory state (cytokine storm) and an acute respiratory distress syndrome (ARDS). AT1R, a member of the G protein-coupled receptor (GPCR) family, modulates Ang II deleterious effects through the activation of multiple downstream signaling pathways, among which are MAP kinases (ERK 1/2, JNK, p38MAPK), receptor tyrosine kinases (PDGF, EGFR, insulin receptor), and nonreceptor tyrosine kinases (Src, JAK/STAT, focal adhesion kinase (FAK)), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. COVID-19 is well known for generating respiratory symptoms, but because ACE2 is expressed in various body tissues, several extrapulmonary pathologies are also manifested, including neurologic disorders, vasculature and myocardial complications, kidney injury, gastrointestinal symptoms, hepatic injury, hyperglycemia, and dermatologic complications. Therefore, the development of drugs based on RAS blockers, such as angiotensin II receptor blockers (ARBs), that inhibit the damaging axis of the RAS cascade may become one of the most promising approaches for the treatment of COVID-19 in the near future. We herein review the general features of AT1R, with a special focus on the receptor-mediated activation of the different downstream signaling pathways leading to specific cellular responses. In addition, we provide the latest insights into the roles of AT1R in COVID-19 outcomes in different systems of the human body, as well as the role of ARBs as tentative pharmacological agents to treat COVID-19.
The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), was first identified in Eastern Asia (Wuhan, China) in December ...2019. The virus then spread to Europe and across all continents where it has led to higher mortality and morbidity, and was declared as a pandemic by the World Health Organization (WHO) in March 2020. Recently, different vaccines have been produced and seem to be more or less effective in protecting from COVID-19. The renin-angiotensin system (RAS), an essential enzymatic cascade involved in maintaining blood pressure and electrolyte balance, is involved in the pathogenicity of COVID-19, since the angiotensin-converting enzyme II (ACE2) acts as the cellular receptor for SARS-CoV-2 in many human tissues and organs. In fact, the viral entrance promotes a downregulation of ACE2 followed by RAS balance dysregulation and an overactivation of the angiotensin II (Ang II)-angiotensin II type I receptor (AT1R) axis, which is characterized by a strong vasoconstriction and the induction of the profibrotic, proapoptotic and proinflammatory signalizations in the lungs and other organs. This mechanism features a massive cytokine storm, hypercoagulation, an acute respiratory distress syndrome (ARDS) and subsequent multiple organ damage. While all individuals are vulnerable to SARS-CoV-2, the disease outcome and severity differ among people and countries and depend on a dual interaction between the virus and the affected host. Many studies have already pointed out the importance of host genetic polymorphisms (especially in the RAS) as well as other related factors such age, gender, lifestyle and habits and underlying pathologies or comorbidities (diabetes and cardiovascular diseases) that could render individuals at higher risk of infection and pathogenicity. In this review, we explore the correlation between all these risk factors as well as how and why they could account for severe post-COVID-19 complications.
The hallmarks of sickle cell disease are anemia and vasculopathy. The aim of this study was to assess the association between air pollution and children's emergency room visits of sickle cell ...patients. We adopted a case-crossover design. Daily counts of children's and adolescents' sickle cell disease emergency room visits from the pediatric emergency unit in São Paulo, Brazil, were evaluated from September 1999 to December 2004, matching by temperature, humidity and controlling for day of the week. Interquartile range increases of the four-day moving averages of PM10, NO2, SO2, CO, and O3 were associated with increases of 18.9% (95%CI: 11.2-26.5), 19% (95%CI: 8.3-29.6), 14.4% (95%CI: 6.5-22.4), 16,5% (95%CI: 8.9-24.0), and 9.8% (95%CI: 1.1-18.6) in total sickle cell emergency room visits, respectively. When the analyses were stratified by pain, PM10 was found to be 40.3% higher than in sickle cell patients without pain symptoms. Exposure to air pollution can affect the cardiovascular health of children and may promote a significant health burden in a sensitive group.
The frequency distributions of cystic fibrosis variants are heterogeneous in Ecuador because of the genetic admixture of its population. The aim of this study was to identify disease-causing variants ...among Ecuadorian cystic fibrosis (CF) patients by next-generation sequencing (NGS) of the entire cystic fibrosis transmembrane conductance regulator (CFTR) gene. The results showed an approximation of the frequencies of pathogenic variants in the population under study and an optimal mutation panel for routine first-line CF molecular diagnosis. One hundred and forty-one patients with suspected CF from the 3 largest Ecuadorian cities (Guayaquil, Quito, and Cuenca) were studied. One hundred and seventy mutated alleles were detected in eighty-five individuals. Twenty-eight disease-causing variants were identified, with p.Phe508del and p.His609Arg being the most frequent (both 24.7%) followed by p.Gly85Glu (11.1%), p.Leu15Pro (9.4%), p.Asn1303Lys (4.1%), and p.Gly542* (2.3%). Together, these variants constituted 76.44% of the detected disease-causing variants. The following six novel potentially disease-associated variants were detected: 3 deletions (CFTR_dele10, CFTR_dele12, and c.2672delA), 1 nonsense variant (p.Cys491*), 1 missense variant (p.Trp496Arg), and 1 complex allele (p.Gly253Arg;Gly451Val). The remaining mutations occurred in isolation and were present in the databases.
•This study is the broadest Cystic Fibrosis patient registry in Ecuador.•Six novel variants were identified by NGS and 2 deletions by microarrays.•H609R and F508del are the most common variants detected.•G85E is the highest reported in the world.•A complex allele was detected in 6 patients in one of the cities.
Inhibitor of nuclear factor kappa B kinase alpha (IKKα) is critical for p100/NF-κB2 phosphorylation and processing into p52 and activation of the noncanonical NF-κB pathway. A patient with recurrent ...infections, skeletal abnormalities, absent secondary lymphoid structures, reduced B cell numbers, hypogammaglobulinemia, and lymphocytic infiltration of intestine and liver was found to have a homozygous p.Y580C mutation in the helix-loop-helix domain of IKKα. The mutation preserves IKKα kinase activity but abolishes the interaction of IKKα with its activator NF-κB–inducing kinase and impairs lymphotoxin-β–driven p100/NF-κB2 processing and
expression. Homozygous IKKα
mutant mice phenocopy the patient findings; lack marginal zone B cells, germinal centers, and antigen-specific T cell response to cutaneous immunization; have impaired
expression; and are susceptible to cutaneous
infection. In addition, these mice demonstrate a severe reduction in medullary thymic epithelial cells, impaired thymocyte negative selection, a restricted TCRVβ repertoire, a selective expansion of potentially autoreactive T cell clones, a decreased frequency of regulatory T cells, and infiltration of liver, pancreas, and lung by activated T cells coinciding with organ damage. Hence, this study identifies IKKα deficiency as a previously undescribed cause of primary immunodeficiency with associated autoimmunity.
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