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Periodontitis is a chronic inflammatory disease which is caused by destruction of the tissues that surrounds and supports the tooth. Deregulation of microRNAs has been reported to cause several inflammatory diseases such as autoimmune disease, chronic periodontitis, and cancer. In the present study, we have investigated the expression pattern of microRNAs let-7a, miR-125b, miR-100, miR-21, and RNA-binding protein LIN-28A among healthy individuals and chronic periodontitis patients. Total RNA was isolated from gingival tissue samples collected from 100 healthy individuals and 100 chronic periodontitis patients. The expression of microRNAs and LIN-28 was performed by qPCR. Target prediction for the microRNAs was done using miRWalk and miRTarbase online databases and the experimentally validated targets were analyzed for their molecular function, biological processes, and related pathways using gProfiler software. The expression analysis revealed that let-7a and miR-21 were upregulated, whereas, miR-100, miR-125b, and LIN-28 were down regulated. The age dependent expression analysis revealed that the expression levels of all the microRNAs and LIN-28 were found to increase with age (more than 50 years), thereby suggesting an increased risk to chronic periodontitis. Among the various targets predicted using miRWalk and miRTarbase databases, NFKB was found to be a common target among all the four microRNAs. gProfiler revealed several functions such as NF-ĸB signaling pathway, cytokine-cytokine receptor interaction, osteoclast differentiation, etc., all of which specific to inflammation and periodontitis., (© 2017 Wiley Periodicals, Inc.)

Periodontitis is a chronic inflammatory disease, caused by interaction between periodontopathic bacteria and the host immune response. MicroRNAs are small, single-stranded molecules, which play a key role in the regulation of diverse biological processes. Dysregulation of microRNAs function can lead to several diseases such as autoimmune and chronic inflammatory diseases. The objective of the study was to determine the association between selected single nucleotide polymorphisms in miR-125a, miR-499 and LIN28 homology A with chronic periodontitis susceptibility in a sample population from south India. Genotyping of the single nucleotide polymorphisms in miR-125a (rs41275794, rs12976445, rs10404453 and rs12975333), miR-499 (rs3746444) and LIN28 homolog A (rs3811463) was performed in DNA from288 controls (individuals with healthy gingiva) and 262 cases (chronic periodontitis patients) by direct dye-terminator sequencing. Disease association analysis revealed a significant association of the variant alleles of the miR-499a polymorphism (rs3746444) in chronic periodontitis [OR=2.07; 95%CI (1.35-3.17)]. The risk associated C-allele frequency was found to be higher in chronic periodontitis subjects as compared to that of healthy individuals. Similar results were also observed in the dominant model [OR=2.42; 95% CI (1.67-3.51)]. The recessive model for miR-125a polymorphism (rs12976445) was also found to be statistically significant with OR=1.54 and 95% CI (1.03-2.30). The haplotype "GCGGCA" was found to be higher in chronic periodontitis subjects than in healthy individuals. Pairwise linkage disequilibrium analysis exhibited that the polymorphisms, rs41275794 and rs12976445 in miR-125a, were in strong linkage equilibrium (D'=0.97). Epistatic interaction by multifactorial dimensionality reduction analysis revealed that the genotypes of the polymorphisms of miR-125a (rs41275794, rs12976445, rs10404453), miR-499a (rs3746444) and LIN28 (rs3811463) were interacting significantly [OR=2.54 (1.65-3.92)], thereby contributing to the risk of chronic periodontitis., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Periodontitis is an inflammatory disease caused by bacterial triggering of the host immune-inflammatory response, which in turn is regulated by microRNAs (miRNA). Polymorphisms in the miRNA pathways affect the expression of several target genes such as tumor necrosis factor-α and interleukins, which are associated with progression of disease., Objective: The objective of this study was to identify the association between the MiR-146a single nucleotide polymorphisms (SNPs) (rs2910164, rs57095329, and rs73318382), the MiR-196a2 (rs11614913) SNP and chronic periodontitis., Methods: Genotyping was performed for the MiR-146a (rs2910164, rs57095329, and rs73318382) and the MiR-196a2 (rs11614913) polymorphisms in 180 healthy controls and 190 cases of chronic periodontitis by the direct Sanger sequencing technique. The strength of the association between the polymorphisms and chronic periodontitis was evaluated using logistic regression analysis. Haplotype and linkage analyses among the polymorphisms was performed. Multifactorial dimensionality reduction was performed to determine epistatic interaction among the polymorphisms., Results: The MiR-196a2 polymorphism revealed a significant inverse association with chronic periodontitis. Haplotype analysis of MiR-146a and MiR-196a2 polymorphisms revealed 13 different combinations, of which 5 were found to have an inverse association with chronic periodontitis., Conclusion: The present study has demonstrated a significant inverse association of MiR-196a2 polymorphism with chronic periodontitis.