Association between SNPs in microRNAs and microRNAs-Machinery Genes with Susceptibility of Leprosy in the Amazon Population

Mitochondrial variants of complex I genes associated with leprosy clinical subtypes

Leprosy is a chronic bacterial infection mainly caused by Mycobacterium leprae that primarily affects skin and peripheral nerves. Due to its ability to absorb carbon from the host cell, the bacillus became dependent on energy production, mainly through oxidative phosphorylation. In fact, variations in genes of Complex I of oxidative phosphorylation encoded by mtDNA have been associated with several diseases in humans, including bacterial infections, which are possible influencers in the host response to leprosy. Here, we investigated the presence of variants in the mtDNA genes encoding Complex I regarding leprosy, as well as the analysis of their pathogenicity in the studied cohort. We found an association of 74 mitochondrial variants with either of the polar forms, Pole T (Borderline Tuberculoid) or Pole L (Borderline Lepromatous and Lepromatous) of leprosy. Notably, six variants were exclusively found in both clinical poles of leprosy, including m.4158A>G and m.4248T>C in MT-ND1, m.13650C>A, m.13674T>C, m.12705C>T and m.13263A>G in MT-ND5, of which there are no previous reports in the global literature. Our observations reveal a substantial number of mutations among different groups of leprosy, highlighting a diverse range of consequences associated with mutations in genes across these groups. Furthermore, we suggest that the six specific variants exclusively identified in the case group could potentially play a crucial role in leprosy susceptibility and its clinical differentiation. These variants are believed to contribute to the instability and dysregulation of oxidative phosphorylation during the infection, further emphasizing their significance.

ncRNAs: an unexplored cellular defense mechanism in leprosy

Leprosy is an infectious disease primarily caused by the obligate intracellular parasite Mycobacterium leprae. Although it has been considered eradicated in many countries, leprosy continues to be a health issue in developing nations. Besides the social stigma associated with it, individuals affected by leprosy may experience nerve damage leading to physical disabilities if the disease is not properly treated or early diagnosed. Leprosy is recognized as a complex disease wherein socioenvironmental factors, immune response, and host genetics interact to contribute to its development. Recently, a new field of study called epigenetics has emerged, revealing that the immune response and other mechanisms related to infectious diseases can be influenced by noncoding RNAs. This review aims to summarize the significant advancements concerning non-coding RNAs in leprosy, discussing the key perspectives on this novel approach to comprehending the pathophysiology of the disease and identifying molecular markers. In our view, investigations on non-coding RNAs in leprosy hold promise and warrant increased attention from researches in this field.

Novel polymorphism rs12402181 in the mature sequence of hsa-miR-3117-3p has a protective effect against breast cancer development by affecting miRNA processing and function

The current study aimed to investigate how the rs12402181 variant in the miR-3117-3p seed region affects miRNA processing and binding ability to the target sequences and breast cancer susceptibility. To study the role of rs12402181 polymorphism in breast cancer, blood samples were examined to investigate the possible association between the genetic variant in the miR-3117 and breast cancer susceptibility. The miR-3117 gene variant was genotyped using PCR-RFLP. The pre-miR-3117 and parts of the flanking region with GG or AA genotype were inserted into a pEGFPN1 expression vector and followed by qPCR to evaluate the effect of SNP on miR-3117-3p expression levels and function. Cell proliferation and migration properties investigated by MTT and wound healing assay. Web server databases were used for further investigation of potential changes in miRNA function. Genotype frequency study in breast cancer patients and healthy controls showed that rs12402181 polymorphism (G > A) is inversely associated with susceptibility to breast cancer (P = 0.03, OR 0.551). The variant allele led to increased production of mature miR-3117 and reduced cell proliferation and migration in MCF7 and T47D cells. These findings suggest that A allele in miR-3117-3p affects the processing of miRNA, causing an increase in the miRNA mature form which can negatively regulate tumor development and migration.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03765-y.

Evaluation of miR-let-7f, miR-125a, and miR-125b expression levels in sputum and serum samples of Iranians and Afghans with pulmonary tuberculosis

Background and Objectives

The role of microRNAs (miRNAs) in tuberculosis infection is well established. As microRNAs are able to change expression profiles according to different conditions, they can be useful biomarkers. Iranians and Afghans with tuberculosis were studied for three immune-related miRNAs (miR-let-7f, miR-125a, and miR-125b).

Materials and Methods

A total of 60 Iranian and Afghan patients with active pulmonary TB were enrolled in the Pulmonary Department of the Pasteur Institute of Iran. Serum and sputum samples were collected simultaneously from all participants. A Real-time PCR was conducted to detect differentially expressed miRNAs.

Results

Iranian (P<0.0001) and Afghan (P<0.0001) serum samples and Afghan (P<0.0001) sputum samples overexpressed miR-125a, whereas Iranian sputum samples showed downregulation (P=0.0039). In both Iranian (P<0.0001; P=0.0007) and Afghan (P<0.0001; P<0.0001) serum and sputum samples, miR-125b was overexpressed. Furthermore, miR-let-7f down-regulation was observed in serum and sputum samples (P<0.0001), whereas Iranian sputum samples had no statistically significant differences (P=0.348).

Conclusion

Overexpression of miR-125a and miR-125b has been detected in Iranian and Afghan samples. In both races, miR-let-7f downregulation has been confirmed. Identification of miRNA profiles under different conditions opens the door to evaluating potential new biomarkers for diagnosis, disease monitoring, and therapeutic markers in TB infection.