MicroRNA - Volume 9, Issue 4, 2020

Introduction: Ischemia-Reperfusion (I/R) injuries are caused by complex interrelated mechanisms and pathways. Regarding the liver, I/R injuries and their clinical manifestations are crucial for the surgical outcome. Despite its importance, there is no broadly accepted therapy either for the prevention or for the management of I/R injury. I/R injury of the liver can occur either during hepatic surgery (warm) or during the transplantation procedure (cold). MicroRNAs play a pivotal role in the mechanism of I/R injury, as they regulate the expression of the cellular participants and humoral factors associated with I/R injury. Objective: In this review, we highlight the microRNAs that are involved in the I/R injury of the liver, and the molecular pathways that they regulate. In addition, we discuss the potential role of circulating microRNAs as biomarkers and their role as pharmacological targets in the prevention, diagnosis and treatment of I/R injuries. Method: We conducted a comprehensive review of the PubMed bibliographic database regarding microRNAs and I/R injuries of the liver. Results: In diagnostics, microRNA panels could replace invasive diagnostic procedures, relieving patients of the associated complications. In therapeutics, microRNAs, agomirs, antagomirs and other drugs can be used to shift the balance between proapoptotic and survival pathways, to alleviate the liver damage caused by I/R. In transplantation procedures, microRNA profiling could decrease the incidence of early graft dysfunction, especially regarding marginal grafts. Conclusion: Although microRNAs seem a very promising clinical tool in the management of I/R injuries, further research is required, until microRNAs become a novel tool in the diagnosis and monitoring of an I/R injury of the liver.

Background: Overweight and obesity prevalence has risen substantially in the last years. MicroRNAs (miRNAs) are factors that regulate gene expression through binding to a complementary sequence of mRNA. Objective: The objective of this review is to determine the association between the expression of miRNAs with overweight and obesity in children. Methods: A systematic search was carried out in Medline (Ovid), EMBASE, LILACS, and CENTRAL. Clinical trials, cohort studies, cases and controls, and cross-section studies were included. Quasi-experimental, prognostic studies, animal experiments, in silico studies, and studies on the adult population were excluded. Results: Seven studies (684 children) were included in this review. Three hundred and sixty-one children had obesity/overweight and 323 had normal weight. 40.64% (278) of the children were boys. The classification of obesity was inconsistent between the studies with several classifications used. A total of 65 miRNAs were reported to be associated with obesity and overweight; at least two studies reported miR-122, miR-122-5p, miR-15b, miR15b-5p, miR191-5p, miR-222, miR-222-3p, miR 486, miR-486-3p and miR-486-5p. Blood samples were the most common samples used to measure miRNAs, and the approaches to select miRNAs were diverse, with four articles performing high-throughput techniques (sequencing and microarrays) before the validation of the miRNAs associated with obesity. Pathway analysis of the repeated miRNAs showed that they were involved in the regulation of metabolic and signaling pathways, including fatty acid metabolism. Conclusion: miRNAs are potential biomarkers of the development of pathologies, such as obesity. It was found a heterogeneous group of these molecules was associated with obesity in children. miR- 15b-5p, miR-486-5p, and hsa-miR-122-5p were considered as good candidates for obesity biomarkers.

Background: Rheumatic Heart Disease (RHD) remains a major cause of cardiovascular diseases and the most devastating effects are shown on children and young adults. RHD is caused due to the interaction between microbial, environmental, immunologic, and genetic factors. The Renin- Angiotensin Aldosterone System (RAAS) has been strongly implicated as the susceptibility pathway in the pathogenesis of the cardiovascular disease. Objective: The present study investigated the modulating effect of Angiotensin II type 1 receptor (AGTR1) 1166A>C polymorphism on the RHD and its clinical features in Saudi Arabia. Methods: AGTR1 1166A>C polymorphism was genotyped in 96 echocardiographically confirmed RHD patients and 142 ethnically matched controls by the TaqMan allelic discrimination method. Results: Genotype distribution of the AGTR1 1166A>C polymorphism was not significantly different between RHD and control groups. Furthermore, AGTR1 1166A>C genotypes are not associated with the clinical features of RHD. These data support that there was no evidence for an association between AGTR1 1166A>C polymorphism and RHD in Saudi Arabia. Conclusion: To the best of our knowledge, this is the first study that has investigated the possible association between AGTR1 1166A>C polymorphism and susceptibility to RHD and its clinical features. Even though the AGTR1 gene, 1166A>C (rs5186), was reported to be associated with hypertension, left ventricular hypertrophy and coronary heart disease. The present study did not find any association between AGTR1 1166A>C polymorphism and RHD in Saudi Arabia. Further studies are needed to confirm our findings.

Background and objective: This study aimed to assess miR21 and miR-29a diagnostic usefulness for HPV infection and Cervical Cancer (CC) detection. Methods: miRs extraction has been performed on HPV-positive, CC and negative control of 43, 50 and 46 individuals, respectively. The expression level of miRs has been analyzed using Real-Time RT-PCR. Results: There was a correlation between the expression of miRs and the Receiver Operating Characteristic (ROC) analysis in CC and HPV-positive patients. Conclusion: The correlation between expressions of miRs is notable. ROC curve analysis could be applied in molecular diagnostic exposure for CC related to HPV infections.

Background: microRNAs (miRNAs, miRs) are small noncoding RNAs that negatively regulate gene expression at the post-transcriptional level and fine-tune gene functions. Global repression of miRNAs expression in different types of human tumors, after exposure to cigarette smoke, or to the hormone estrogen, have been shown to be associated with guanine (G) enrichment in the terminal Loops (TLs) of their precursors. Methods: We integrated the G content of miRNA mature forms and precursor miRNA TLs with their described function in the literature, using the PubMed database. Gene Ontology term analysis was used to describe the pathways in which the G-enriched miRNA targets are involved. Results: Herein, we show an association between the relative G enrichment of precursor miRNAs’ TLs and their tendency to act as tumor suppressor miRs in human lung and breast cancers. Another association was observed between the high G content of the miRNAs 5-mature forms and their tendency to act as oncomiRs. Conclusion: The results support previous findings showing that the G sequence content is an important feature determining miRNA expression and function, and opens the way for future cancer investigations in this direction.

Background: Learning and memory are basic aspects of neurogenetics as most of the neurological disorders start with dementia or memory loss. Several genes associated with memory formation have been discovered. MicroRNA genes, miR-1000 and miR-375, were reported to be associated with neural integration and glucose homeostasis in some insects and vertebrates. However, the neuronal function of these genes is yet to be established in D. melanogaster. Objective: The possible role of miR-1000 and miR-375 in learning and memory formation in this fly has been explored in the present study. Methods: Both types of appetitive and aversive olfactory conditional learning were tested in the miR- 1000 and miR-375 knockout (KO) strains and compared with the wild one. Five days old third instar larvae were trained by allowing them to be associated with an odor with reward (fructose) or punishment (salt). Then, the larvae were tested to calculate their preferences to the odor they were trained with. Learning Index (LI) values and larval locomotion speed were calculated for all strains. Results: Knockout strain of miR-1000 showed significant deficiency in both appetitive and aversive memory formation whereas miR-375 KO strain showed a significantly lower response only in appetitive one. Conclusion: The results of the present study indicate an important role of miR-1000 and miR-375 genes in forming short-term memory in D. melanogaster.

Background: Epithelial Ovarian Cancer (EOC) is often challenging to diagnose, even though histological examination. MicroRNA (miRNA or miRNA) is bound to the target messenger RNA (mRNA) due to which the mRNA molecules are silenced. The identification of miRNA expression- based EOC subtypes is considered a critical means of prognostication. So far, the studies on EOC subtypes have not been well characterized. Objective: This study aimed to confirm the existence of miRNAs in EOC and to assess their potential as clinical biomarkers for EOC. Methods: We sampled 25 ovarian tumor tissues from patients with human ovarian tumors (17 malignant; 12 serous EOC, five non-serous EOC, and eight benign ovarian tumors). miRNA microarray detection was performed to identify EOC miRNAs. Real-time PCR was adapted for the validation of differentially expressed miRNAs detected by microarray analysis related to hybridization intensity. Results: The results confirmed that miRNAs exist in EOC, relative expression of EOC miRNAs demonstrated that the upregulation of miR-483-5p, and downregulation of miR-127-3p, and miR- 532-5p were significantly expressed in the malignant group than in the benign group at p < 0.05. Besides, miR-483-5p could also distinguish EOC subtypes between serous EOC and non-serous EOC, with a p < 0.05. Conclusion: A comprehensive miRNA expression profiling can help to refine subtype classification in EOC, opening new opportunities for identifying clinically applicable markers for improved stratification and diagnostics of ovarian tumors.

Objective: To observe the expression patterns of salivary mRNA 21 in different stages and grades of OSMF and also in habitual areca nut chewers without OSMF. Subjects and Methods: The study consisted of a total of 185 samples, where 61 patients had chewing habits (chewing gutkha and other forms of areca nut) and had OSMF (Group 1). 61 patients had chewing habits but did not have OSMF (Group 2), and 63 were normal healthy patients (control group) without any chewing habits (Group 3). Unstimulated saliva samples were collected from patients following the standard operating procedures. miRNA 21 was isolated and purified from saliva samples using the miRNeasy Mini Kit, Qiagen. The primers for miRNA relative quantification analysis were designed using the Primer Express software of Applied Biosystems. Quantification of all the samples was carried out using SYBR chemistry in an Applied Biosystems Real-Time PCR. Results: There was no statistically significant difference between the demographic characteristics of patients. There was a statistically significant difference between the expressions of miRNA 21 amongst the three groups noted in Kruskal Wallis test. (<0.001*) A post hoc test was perfomed to confirm the statistical difference between patients within all three groups. There was no statistically significant difference noted between the OSMF group and patients with chewing habits group (G1 vs. G2 p: 0.10), but there was a significant difference when compared with normal patients. (G1 vs. G3 p: <0.001*) and (G2 vs. G3 <0.001*). Conclusion: This study concludes that miRNA 21 is overexpressed in OSMF and chewing habit patients. But the expression levels were not significantly associated with the severity of the disease process. A long term and large scale studies are required to assess its application as a diagnostic profibrotic marker in OSMF.

Introduction: Prostate Cancer (PCa) is the second most common cancer in males and the fifth in cancer-associated mortality. Although the Prostate-Specific Antigen (PSA) test is widely used in PCa screenings, it has significant limitations in the differential diagnosis of PCa. Therefore, studies on developing new biomarkers for PCa diagnosis are ongoing. MiRNAs are good candidate biomarkers for the diagnosis of cancers, including prostate cancer, as they can be easily detected from circulation. Objective: In this study, it is aimed to determine the diagnostic value of serum levels of miR-223-3p and -223-5p in Benign Prostate Hyperplasia (BPH), Chronic Prostatitis (CP) and Prostate Cancer (PCa). Methods: Serum samples were collected from 68 patients in total (25 BPH, 10 CP, 33 PCa). MiR-223- 3p and -223-5p levels were measured in serum with qRT-PCR. The Ct values of miRNAs were normalized according to the Ct value of ce-miR-39 and calculated -ΔCt values were used for statistical analyses. Results: The serum levels of miR-223-3p and -223-5p were downregulated in the PCa and CP groups, compared to the BPH group. There was no statistically significant difference between PCa and CP groups. The sensitivity and specificity of miR-223-3p, -223-5p and their combination were calculated as 88% and 88%; 86% and 79%; 93% and 92% in discriminating BPH and PCa groups, respectively. Conclusion: In this study, it was shown that miR-223-3p and -223-5p were both detectable in circulation. miR-223-3p, -223-5p, and their combination may be good candidate biomarkers for prostate cancer diagnosis. Also, observation of similar serum levels of miR-223-3p and -223-5p between CP and PCa groups suggests that miR-223 may play a role in prostate cancer development originated from chronic inflammation.

Background: Single-Nucleotide Polymorphisms (SNPs) in genes responsible for coding microRNAs (miRNAs) are shown to be crucial in progression of Breast Cancer (BC). Objective: The purpose of this meta-analysis is to obtain more definitive and reliable results due to the ambiguity and inconsistency of the previous findings in this regard. This study aimed at clarifying the association of mir14a polymorphisms with breast cancer. Methods: We searched PubMed, EMBASE, Web of Science and Google Scholar databases for papers published before August 10, 2019. Afterward, genotypes’ distribution, genotyping methods and ethnicity groups were extracted and Overall analyses were conducted. A total number of seventeen researches on 7676 subjects and 7476 controls were found to meet our criteria in this meta-analysis. Results: Our observations confirmed the increased risk in breast cancer with rs 2910164 polymorphism in three genetic models: allele contrast fixed genetic model, Recessive fixed genetic model and CC vs. GG genetic model (P value 0.0109, 0.0404 and 0.0019, respectively). Conclusion: The rs2910164 polymorphism is associated with increased breast cancer risk. We suggest that more multicenter studies with larger samples investigate this matter to further clarify the association and verify our findings.