[Vitamin D and polymorphisms of VDR and GC genes in the severity and mortality from COVID-19. A systematic review]. / Vitamina D y polimorfismos de los genes VDR y GC en la severidad y mortalidad por COVID-19. Una revisión sistemática.

Introduction: Previous studies have pointed to a possible relationship between vitamin D deficiency and the severity of the disease promoted by SARS-CoV-2, reducing respiratory and cardiovascular complications caused by a hyperreaction of the immune system known as "cytokine storm". This vitamin exerts multiple functions that depend on the presence and levels of different proteins, such as the vitamin D receptor (VDR) and the vitamin D binding protein (DBP), and the existence of single nucleotide polymorphisms (SNPs) of the genes that encode these proteins. The objective of this review is to assess whether some VDR and GC SNPs are risk factors for the most severe forms of COVID-19 disease and whether they condition the response to vitamin D supplementation. A search was performed in PubMed, Google Scholar and Scielo, finding that genotypes in patients affected by COVID-19, were rarely performed, although some studies find a relationship between different alleles and the severity of the disease. The ApaI polymorphism of the VDR gene stands out, as the minor allele "a" increases the risk of mortality from COVID-19 (OR = 11.828, CI: 2,493-56,104, p = 0.002). Results divergency in the efficacy of vitamin D supplementation suggest the need for a larger number of studies. In conclusion, the study of VDR and GC polymorphisms seems essential to effectively treat vitamin D deficiency and particularly to protect against COVID-19. Well-designed studies are needed to elucidate whether plasma vitamin D levels play a role of casuality or causality.

Introducción: Estudios previos han señalado una posible relación entre la deficiencia de la vitamina D y la severidad de la enfermedad promovida por el SARS-CoV-2, reduciendo las complicaciones respiratorias y cardiovasculares causadas por una respuesta exacerbada del sistema inmune. Esta vitamina ejerce múltiples funciones que dependen de la presencia y niveles de diferentes proteínas, como el receptor de la vitamina D (VDR) y la proteína de unión de la vitamina D (DBP), y de la existencia de polimorfismos de un solo nucleótido (SNP) de los genes que codifican a estas proteínas. El objetivo de esta revisión es evaluar si algunos SNP de VDR y GC son factores de riesgo de las formas más severas de la enfermedad COVID-19 y si condicionan la respuesta a la suplementación con vitamina D. Se realizó una búsqueda en PubMed, Google Scholar y Scielo, encontrándose que son escasos los genotipados en pacientes afectados por COVID-19, aunque algunos trabajos hallan una relación entre diferentes alelos y la severidad de la enfermedad. Destaca el polimorfismo ApaI del gen VDR, el cual alelo menor "a" aumenta el riesgo de mortalidad por COVID-19 (OR = 11,828, CI: 2.493-56.104, p = 0,002). La divergencia de resultados en la eficacia de la suplementación de vitamina D sugiere la necesidad de un mayor número de estudios. En conclusión, el estudio de polimorfismos VDR y GC resulta fundamental para tratar eficazmente la deficiencia de vitamina D y en particular en la protección frente a COVID-19. Se necesitan estudios bien diseñados para dilucidar si los niveles plasmáticos de vitamina D juegan un papel de casualidad o causalidad.

Nickel import and export in the human pathogen Helicobacter pylori, perspectives from molecular modelling.

The uptake of essential metal ions and the ability to extrude them when their excess causes toxicity are crucial processes for all living beings. Nickel is a virulence factor for several human pathogens and in particular for the human gastric pathogen Helicobacter pylori because of its crucial role in the catalytic activity of two Ni-dependent enzymes, urease and hydrogenase. H. pylori requires efficient uptake mechanisms to import Ni(II) because of its scarcity in the human body, but the molecular details of Ni(II) homeostasis are not fully known. Here we offer a structural framework for the machinery of Ni(II) import/export in H. pylori, obtained through comparative modelling and macromolecular docking. The model structures reported in this perspective are initial steps towards the understanding of these processes at the molecular level and in the direction to exploit them to eradicate infections caused by this family of pathogens. The differences between the structural models obtained by using both the recently released neural network-based approach implemented in AlphaFold2 and a more classical user-driven modelling procedure are also discussed.