Background: The presence of sequence variants in miRNA genes may influence their processing, expression and binding to target mRNAs. Since single miRNA can have a large number of potential mRNA targets, even minor variations in its expression can have influences on hundreds of putative mRNAs. Methods: Here, we evaluated 101 paired samples (cancer and normal tissues) from non-small cell lung carcinoma (NSCLC) patients to study the genotype distribution of single nucleotide polymorphisms (SNPs) in miR-146a (rs2910164 C-G), miR-149 (rs2292832 C-T), miR-196a2 (rs11614913 C-T) and miR-499 (rs3746444 G-A) and their influence on the expression of respective miRNAs.Results: Relative expression of miR-146a, miR-149 and miR-499 were comparable in NSCLC and in paired control tissues. On the contrary, we clearly detected a significant increase (p-0.001) of miR-196a2 expression in NSCLC. In particular we found a significant association between miR196a2 CC genotype and high expression, whereas TT genotype showed a very low expression in comparison to both CT (p-0.005) and CC patients (p-0.01). We did not find any association between miR-149, miR-196a2 and miR-499 genotype and risk of NSCLC. Conversely, CG genotype of miR-146a appeared associated to an increased risk for NSCLC (ps0.042 and 1.77 OR). Conclusions:Our results seem to demonstrate that sequence variants of miR-196a2 can have an influence on its expression, while miR-146a can have a role in increasing the risk of NSCLC.

No abstract

a b s t r a c tStudies on miRNA profiling revealed that a large number of them are significantly deregulated in human cancers. The molecular mechanisms of this deregulation are not totally clarified, even if genetics and epigenetics are frequently involved.Single nucleotide polymorphisms (SNPs) are the most common type of genetic variation in the human genome. A SNP into miRNA gene might affect the transcription of primary miRNA, its processing and miRNA-mRNA interaction. We investigated the distribution of sequence variants of miR-146a, miR-196a2, miR-499 and miR-149 in colorectal cancer (CRC) and their effect on miRNA expression. Each variant was identified with HRM. For miR-499 we demonstrated a significant reduction of its expression in CRC connected to a specific genotype.To evaluate the epigenetic effects on miRNA genes in CRC, we investigated the influence of DNA methylation on miR-34b, miR-34c and miR-9-1 expression. We aimed to verify the relationship between the methylation status of these miRNA genes and their relative expression in tumor samples. For the quantification of DNA methylation we adopted a method based on Differential High Resolution Melting (D-HRM).

No abstract

Although accumulating data have investigated the effect of SARS-CoV-2 mutations on antibody neutralizing activity, less is known about T cell immunity. In this work, we found that the ancestral (Wuhan strain) Spike protein can efficaciously reactivate CD4+ T cell memory in subjects with previous Alpha variant infection. This finding has practical implications, as in many countries only one vaccine dose is currently administered to individuals with previous COVID-19, independently of which SARS-CoV-2 variant was responsible of the infection. We also found that only a minority of Spike-specific CD4+ T cells targets regions mutated in Alpha, Beta and Delta variants, both after natural infection and vaccination. Finally, we found that the vast majority of Spike-specific CD4+ T cell memory response induced by natural infection or mRNA vaccination is conserved also against Omicron variant. This is of importance, as this newly emerged strain is responsible for a sudden rise in COVID-19 cases worldwide due to its increased transmissibility and ability to evade antibody neutralization. Collectively, these observations suggest that most of the memory CD4+ T cell response is conserved against SARS-CoV-2 variants of concern, providing an efficacious line of defense that can protect from the development of severe forms of COVID-19.