Functional analysis of CTLA4 promoter variant and its possible implication in colorectal cancer immunotherapy

BackgroundColorectal cancer (CRC) is a prevalent cancer, ranking as the third most common. Recent advances in our understanding of the molecular causes of this disease have highlighted the crucial role of tumor immune evasion in its initiation and progression. CTLA4, a receptor that acts as a negative regulator of T cell responses, plays a pivotal role in this process, and genetic variations in CTLA4 have been linked to CRC susceptibility, prognosis, and response to therapy.MethodsWe conducted a case-control study involving 98 CRC patients and 424 controls. We genotyped the CTLA4 c.-319C > T variant (rs5742909) and performed an association analysis by comparing allele frequencies between the patients and controls. To assess the potential functional impact of this variant, we first performed an In Silico analysis of transcription factor binding sites using Genomatix. Finally, to validate our findings, we conducted a luciferase reporter gene assay using different cell lines and an electrophoretic mobility shift assay (EMSA).ResultsThe case-control association analysis revealed a significant association between CTLA4 c.-319C > T and CRC susceptibility (p = 0.023; OR 1.89; 95% CI = 1.11–3.23). Genomatix analysis identified LEF1 and TCF7 transcription factors as specific binders to CTLA4 c.-319C. The reporter gene assay demonstrated notable differences in luciferase activity between the c.-319 C and T alleles in COS-7, HCT116, and Jurkat cell lines. EMSA analysis showed differences in TCF7 interaction with the CTLA4 C and T alleles.ConclusionCTLA4 c.-319C > T is associated with CRC susceptibility. Based on our functional validation results, we proposed that CTLA4 c.-319C > T alters gene expression at the transcriptional level, triggering a stronger negative regulation of T-cells and immune tumoral evasion

Genetic and non-genetic factors associated with severe SARS-COV-2 Infection and long-COVID in a sample of tha colombian population

Introducción: Existe una heterogenea respuesta a la infección por SARS-CoV-2 dada por variabilidad interindividual mediada por factores clínicos, virales y genéticos del huésped. Pocos estudios a nivel latinoamericano han explorado la implicación de variantes genéticas en la variabilidad fenotípica de la evolución y desenlaces de esta enfermedad. El principal objetivo del estudio fue evaluar la asociación de factores clínicos y genéticos con la severidad de COVID-19 y la presencia de COVID-19 prolongado. Metodología: Utilizando un diseño metodológico tipo casos y controles (n = 112; 1:1). Se recolectaron variables clínicas, sociodemográficas, y genéticas a través de encuestas, la historia clínica y secuenciación de siguiente generación (NGS). Se determinó la asociación de las variables clínicas y de 81 polimorfismos de nucleótido simple (SNP) con severidad de COVID-19 y presencia de COVID-19 prolongado. Las variables significativas se usaron para construir un modelo predictivo de severidad de COVID-19 y COVID-19 prolongado. Resultados y discusión: En concordancia con reportes previos, variables clínicas como sexo masculino, obesidad, diabetes mellitus, tos, disnea, entre otras, exhibieron asociación estadísticamente significativa con la severidad a COVID-19. Varios SNP presentaron asociación significativa con severidad, tales como rs11385942 (p<0.01; OR=10.88; 95% CI=1.36-86.51), rs10490770 (p<0.01; OR=9.699; 95% CI=1.20-77.89), rs35081325 (p<0.01; OR=9.699; 95% CI=1.20-77.89) y rs73064425 (p<0.01; OR=9.699; 95% CI=1.20-77.89). Múltiples síntomas respiratorios y sistémicos presentes durante la infección tuvieron asociación con la presencia de COVID-19 prolongado, al igual que algunos SNP como rs8178521 del gen IL10RB (p<0.01; OR=2.51; 95% CI=1.27-4.94). Se ilustró que los modelos mixtos que integran variables clínicas y genéticas tienen el mejor poder predictivo.Introduction: There is a heterogeneous response to SARS-CoV-2 infection given by interindividual variability mediated by clinical, viral and genetic factors of the host. Few studies at the Latin American level have explored the involvement of genetic variants in the phenotypic variability of the evolution and outcomes of this disease. The main objective of the study was to evaluate the association of clinical and genetic factors with the severity of COVID-19 and the presence of prolonged COVID-19. Methodology: Using a case-control methodological design (n = 112; 1:1). Clinical, sociodemographic, and genetic variables were collected through surveys, clinical history, and next-generation sequencing (NGS). The association of clinical variables and 81 single nucleotide polymorphisms (SNPs) with severity of COVID-19 and presence of prolonged COVID-19 was determined. Significant variables were used to build a predictive model of COVID-19 severity and prolonged COVID-19. Results and discussion: In accordance with previous reports, clinical variables such as male sex, obesity, diabetes mellitus, cough, dyspnea, among others, exhibited a statistically significant association with the severity of COVID-19. Several SNPs presented a significant association with severity, such as rs11385942 (p<0.01; OR=10.88; 95% CI=1.36-86.51), rs10490770 (p<0.01; OR=9.699; 95% CI=1.20-77.89), rs35081325 ( p<0.01; OR=9.699; 95% CI=1.20-77.89) and rs73064425 (p<0.01; OR=9.699; 95% CI=1.20-77.89). Multiple respiratory and systemic symptoms present during the infection were associated with the presence of prolonged COVID-19, as were some SNPs such as IL10RB gene rs8178521 (p<0.01; OR=2.51; 95% CI=1.27-4.94). It was illustrated that mixed models that integrate clinical and genetic variables have the best predictive power.Universidad del RosarioHospital Universitario Mayor Méder

IL-17A produced by POMC neurons regulates diet-induced obesity

Summary: Overeating leads to obesity, a low-grade inflammatory condition involving interleukin-17A (IL-17A). While pro-opiomelanocortin (POMC) neurons regulate feeding, their connection with IL-17A is not well understood. To impair IL-17A signaling in POMC neurons, IL-17A receptor (Il17ra) was deleted by crossing IL17ra-flox and Pomc-Cre mice. Despite effective deletion, these mice showed no differences in body weight or adiposity compared to control mice, challenging the idea that IL-17A induces obesity through POMC neuron regulation. However, both groups exhibited reduced weight gain and adiposity upon high-fat diet compared to mice carrying only the floxed alleles, suggesting independent effects of Pomc-Cre transgene on body weight. Further analysis reveals that POMC neurons express IL-17A, and reduction in number of POMC neurons in Pomc-Cre mice could be linked to decreased IL-17A expression, which correlates with reduced adipocyte gene expression associated with obesity. Our data underscore an unexpected crosstalk between IL-17A-producing POMC neurons and the endocrine system in obesity regulation

Next-generation sequencing of host genetics risk factors associated with COVID-19 severity and long-COVID in Colombian population

Abstract Coronavirus disease 2019 (COVID-19) was considered a major public health burden worldwide. Multiple studies have shown that susceptibility to severe infections and the development of long-term symptoms is significantly influenced by viral and host factors. These findings have highlighted the potential of host genetic markers to identify high-risk individuals and develop target interventions to reduce morbimortality. Despite its importance, genetic host factors remain largely understudied in Latin-American populations. Using a case–control design and a custom next-generation sequencing (NGS) panel encompassing 81 genetic variants and 74 genes previously associated with COVID-19 severity and long-COVID, we analyzed 56 individuals with asymptomatic or mild COVID-19 and 56 severe and critical cases. In agreement with previous studies, our results support the association between several clinical variables, including male sex, obesity and common symptoms like cough and dyspnea, and severe COVID-19. Remarkably, thirteen genetic variants showed an association with COVID-19 severity. Among these variants, rs11385942 (p < 0.01; OR = 10.88; 95% CI = 1.36–86.51) located in the LZTFL1 gene, and rs35775079 (p = 0.02; OR = 8.53; 95% CI = 1.05–69.45) located in CCR3 showed the strongest associations. Various respiratory and systemic symptoms, along with the rs8178521 variant (p < 0.01; OR = 2.51; 95% CI = 1.27–4.94) in the IL10RB gene, were significantly associated with the presence of long-COVID. The results of the predictive model comparison showed that the mixed model, which incorporates genetic and non-genetic variables, outperforms clinical and genetic models. To our knowledge, this is the first study in Colombia and Latin-America proposing a predictive model for COVID-19 severity and long-COVID based on genomic analysis. Our study highlights the usefulness of genomic approaches to studying host genetic risk factors in specific populations. The methodology used allowed us to validate several genetic variants previously associated with COVID-19 severity and long-COVID. Finally, the integrated model illustrates the importance of considering genetic factors in precision medicine of infectious diseases

A Pharmacogenetic Study of CYP2C19 in Acute Coronary Syndrome Patients of Colombian Origin Reveals New Polymorphisms Potentially Related to Clopidogrel Therapy

Clopidogrel, an oral platelet P2Y12 receptor blocker, is used in the treatment of acute coronary syndrome. Interindividual variability in treatment response and the occurrence of adverse effects has been attributed to genetic variants in CYP2C19. The analysis of relevant pharmacogenes in ethnically heterogeneous and poorly studied populations contributes to the implementation of personalized medicine. We analyzed the coding and regulatory regions of CYP2C19 in 166 patients with acute coronary syndrome (ACS) treated with clopidogrel. The allele frequencies of CYP2C19 alleles *1, *2, *4, *17, *27 and *33 alleles were 86.1%, 7.2%, 0.3%, 10.2%, 0.3% and 0.3%, respectively. A new potentially pathogenic mutation (p.L15H) and five intronic variants with potential splicing effects were detected. In 14.4% of the patients, a new haplotype in strong linkage disequilibrium was identified. The clinical outcome indicated that 13.5% of the patients presented adverse drugs reactions with a predominance of bleeding while 25% of these patients were carriers of at least one polymorphic allele. We propose that new regulatory single-nucleotide variants (SNVs) might potentially influence the response to clopidogrel in Colombian individuals