Study on the Role of Mitophagy Receptor PHB2 in Doubly Uniparental Inheritance of Hyriopsis cumingii

In bivalves, the heterogeneity of mitochondrial DNA and its unique mode of transmission have been the focus of attention, which is called doubly uniparental inheritance (DUI). Prohibitin-2 (phb2) is a mitochondrial inner membrane protein that is a key mitophagy receptor for parental mitochondrial removal. Hyriopsis cumingii is a freshwater bivalve in China, the full-length cDNA of H. cumingii phb2 (named Hcphb2) is 2917 bp and encodes a total of 300 amino acids, a highly conserved sequence. Hcphb2 was highly expressed in the ovary. In the gonadal tissues of 5- to 8-month-old female mussels, the expression level of Hcphb2 continued to significantly increase. After Hcphb2 siRNA interference in 6-month-old female mussels, the expression of M-COII, a marker gene on M-type mitochondria, showed a considerable increase (p < 0.05). In contrast, the expression of autophagosome formation and maturation-related genes, atg4b, atg5, atg12, and atg16l, in the ATG family genes was significantly decreased (p < 0.01). Subcellular localization showed that Hcphb2 appeared in spermatogonia, spermatocyte, spermatid, and sperm, and its location changes synchronize with the behavior of M-type mitochondria location changes in DUI species. And it was found that miR-184 negatively regulated Hcphb2. The above results suggest that the mitochondrial autophagy receptor gene Hcphb2 may be associated with the degradation of M-type mitochondria in the freshwater mussel. This process requires multiple genes to participate, of which Hcphb2 and autophagy genes are only some of those that may play a role.

Upregulation of miR-184 and miR-19a-3p induces endothelial dysfunction by targeting AGO2 in Kawasaki disease

BACKGROUND

Endothelial dysfunction is a marked feature of Kawasaki disease during convalescence, but its pathogenesis is currently unclear. Circulating microRNAs (miRNAs) are associated with the progression of Kawasaki disease. However, the role and mechanism of circulating miRNAs in endothelial dysfunction are largely unknown. Kawasaki disease patients were found to have a unique circulating miRNA profile, including upregulation of miRNA-210-3p, miR-184 and miR-19a-3p, compared to non-Kawasaki disease febrile controls. This study aimed to investigate the effects of these three miRNAs on endothelial function.

METHODS

Overexpression of miRNAs in human umbilical vein endothelial cells was done by transfection of miRNA mimics. The tube formation assay was used to evaluate the function of human umbilical vein endothelial cells. The potential binding sites of miRNAs on 3'untranslated regions were predicted by using TargetScan database and validated by dual luciferase reporter assay. The protein expression of AGO2, PTEN and VEGF in human umbilical vein endothelial cells was detected by Western blot. Overexpression of AGO2 in human umbilical vein endothelial cells was done by transfection of AGO2 expression plasmids.

RESULTS

Overexpression of miRNA-184 and miRNA-19a-3p, but not miR-210-3p, impaired the function of human umbilical vein endothelial cells. Mechanistically, miR-184 and miR-19a-3p could target the 3'untranslated regions of AGO2 mRNA to downregulate its expression and subsequently impede the AGO2/PTEN/VEGF axis. To be noted, the rescue of the expression of AGO2 remarkably recovered the function that was impaired by overexpression of miRNA-184 and miRNA-19a-3p.

CONCLUSIONS

This study suggested that miR-184 and miR-19a-3p could target AGO2/PTEN/VEGF axis to induce endothelial dysfunction in Kawasaki disease.

miRNA, lncRNA and circRNA: targeted molecules with therapeutic promises in Mycoplasma pneumoniae infection

Mycoplasma pneumoniae (MP) is primarily recognized as a respiratory pathogen that causes community-acquired pneumonia, which can lead to acute upper and lower airway inflammation and extrapulmonary syndrome. Refractory pneumonia caused by MP can cause severe complications and even be life-threatening, particularly in infants and the elderly. It is well-known that non-coding RNAs (ncRNAs) represented by miRNAs, lncRNAs and circRNAs have been manifested to be widely involved in the regulation of gene expression. Growing evidence indicates that these ncRNAs have distinct differentiated expression in MP infection and affect multiple biological processes, playing an indispensable role in the initiation and promotion of MP infection. However, the epigenetic mechanisms involved in the development of MP infection remain unclear. This article reviews the mechanisms by which miRNAs, lncRNAs, and circRNAs mediate MP infection, such as inflammatory responses, apoptosis and pulmonary fibrosis. Focusing on miRNAs, lncRNAs and circRNAs associated with MP infection could provide new insights into this disease's early diagnosis and therapeutic approaches.

Emerging Role of microRNAs in Stroke Protection Elicited by Remote Postconditioning

Remote ischemic conditioning (RIC) represents an innovative and attractive neuroprotective approach in brain ischemia. The purpose of this intervention is to activate endogenous tolerance mechanisms by inflicting a subliminal ischemia injury to the limbs, or to another “remote” region, leading to a protective systemic response against ischemic brain injury. Among the multiple candidates that have been proposed as putative mediators of the protective effect generated by the subthreshold peripheral ischemic insult, it has been hypothesized that microRNAs may play a vital role in the infarct-sparing effect of RIC. The effect of miRNAs can be exploited at different levels: (1) as transducers of protective messages to the brain or (2) as effectors of brain protection. The purpose of the present review is to summarize the most recent evidence supporting the involvement of microRNAs in brain protection elicited by remote conditioning, highlighting potential and pitfalls in their exploitation as diagnostic and therapeutic tools. The understanding of these processes could help provide light on the molecular pathways involved in brain protection for the future development of miRNA-based theranostic agents in stroke.

Potential Relationship between the Changes in Circulating microRNAs and the Improvement in Glycaemic Control Induced by Grape Pomace Supplementation

MicroRNAs (miRNAs) represent important tools in medicine and nutrition as new biomarkers, and can act as mediators of nutritional and pharmacological interventions. The aim of the present study was to analyse the effect of grape pomace supplementation on the expression of seven selected miRNAs and their potential relationship with the observed positive effect on glycaemic control, in order to shed light on the mechanism underlying the beneficial effect of this dietary intervention. For this purpose, plasma samples were obtained from 49 subjects with metabolic syndrome. After supplementation with grape pomace (6 weeks), these subjects were categorised as responders (n = 23) or non-responders (n = 26) according to the changes in their fasting insulin rate. MiRNA expression at baseline and at the end of the supplementation was analysed by RT-PCR, and the MiRecords Database was used to identify potential target genes for the studied miRNAs. The increase observed in miR-23a in the whole cohort was present in both subgroups of participants. The increase in miR-181a was significant among non-responders but not responders. The decrease in miR-30c and miR-222 was found in the responders, but not in the non-responders. No changes were observed in miR-10a, miR-151a, miR-181a, and miR-let-7a expressions. After analysing these results, a potential involvement of the reduced expression of miR-30c and miR-222, two microRNAs associated with insulin resistance and diabetes, in the improvement of glycaemic control produced by grape pomace administration, can be proposed. Further research is needed to confirm the involvement of glycolytic enzymes, PI3K, AMPK, and IRS-1 in the effect of grape pomace, as suggested by the changes induced in microRNAs.

MicroRNA Dysregulation in Parkinson's Disease: A Narrative Review

Parkinson’s disease (PD) is a severely debilitating neurodegenerative disease, affecting the motor system, leading to resting tremor, cogwheel rigidity, bradykinesia, walking and gait difficulties, and postural instability. The severe loss of dopaminergic neurons in the substantia nigra pars compacta causes striatal dopamine deficiency and the presence of Lewy bodies indicates a pathological hallmark of PD. Although the current treatment of PD aims to preserve dopaminergic neurons or to replace dopamine depletion in the brain, it is notable that complete recovery from the disease is yet to be achieved. Given the complexity and multisystem effects of PD, the underlying mechanisms of PD pathogenesis are yet to be elucidated. The advancement of medical technologies has given some insights in understanding the mechanism and potential treatment of PD with a special interest in the role of microRNAs (miRNAs) to unravel the pathophysiology of PD. In PD patients, it was found that striatal brain tissue and dopaminergic neurons from the substantia nigra demonstrated dysregulated miRNAs expression profiles. Hence, dysregulation of miRNAs may contribute to the pathogenesis of PD through modulation of PD-associated gene and protein expression. This review will discuss recent findings on PD-associated miRNAs dysregulation, from the regulation of PD-associated genes, dopaminergic neuron survival, α-synuclein-induced inflammation and circulating miRNAs. The next section of this review also provides an update on the potential uses of miRNAs as diagnostic biomarkers and therapeutic tools for PD.

Factors Involved in miRNA Processing Change Its Expression Level during Imitation of Hypoxia in BeWo b30 Cells

One of the main complications of pregnancy and causes of maternal and perinatal mortality is preeclampsia. The pathophysiology of preeclampsia is associated with the development of placenta and fetal hypoxia and secretion of a number of effective molecules. The human choriocarcinoma cell line BeWo b30 is often used as a model of the placental barrier. It was shown that oxyquinoline derivatives can mimic hypoxia by suppressing HIF-prolyl hydroxylases and the accumulation of HIF-1α. This effect also leads to a change in the expression of microRNAs and their target genes. However, with hypoxia in cells, not only the level of individual miRNAs but also the ratio of miRNA isoforms (isomiRs) can change, presumably due to inaccuracies in the work of the Drosha and Dicer enzymes. In this work, we showed a change in the expression of the factors involved in the maturation of miRNAs when simulating hypoxia in BeWo b30 cells with an oxyquinoline derivative, which may be one of the causes for the change in the ratio of miRNA isoforms.

Overexpression of miR-331 Indicates Poor Prognosis and Promotes Progression of Breast Cancer

BACKGROUND

With the increasing number of cases of breast cancer every year, the exploration of novel biomarkers has drawn attention. miR-331 has been demonstrated to play a role in various cancers, but its role in breast cancer is still unknown.

METHODS

In this study, we included 121 patients with breast cancer treated at Affiliated Hospital of Weifang Medical University. Breast cancer tissues and adjacent normal tissues were collected during the surgery. The expression of miR-331 in breast cancer tissues and cell lines was detected by qRT-PCR assay. Then, with the help of Kaplan-Meier survival and Cox regression analyses, the role of miR-331 in the prognosis of breast cancer was analyzed. Finally, the effect of miR-331 on cell proliferation, migration, and invasion was investigated with CCK-8 assay and transwell assay.

RESULTS

miR-331 was significantly upregulated in breast cancer tissues compared with normal tissues. The overexpression of miR-331 was associated with lymph node metastasis, TNM stage, and poor prognosis. From the results of Cox regression analyses, it was found that miR-331 served as an independent indicator in the prognosis of breast cancer. In addition, miR-331 was also found to be upregulated in breast cancer cells, which promoted cell proliferation, migration, and invasion of breast cancer.

CONCLUSION

As shown from our data, miR-331 may be a potential prognostic biomarker in breast cancer. Moreover, the development and progression of breast cancer may involve miR-331. These findings suggest a novel therapeutic target for the treatment of breast cancer.

Role of ACE2/TMPRSS2 genes regulation by intestinal microRNA isoforms in the COVID-19 pathogenesis

Coronavirus SARS-CoV-2, the cause of the COVID-19 pandemic, enters the cell by binding the cell surface proteins: angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). The expression of these proteins varies significantly in individual organs and tissues of the human body. One of the proteins’ expression regulation mechanisms is based on the activity of the microRNA (miRNA) molecules, small non-coding RNAs, the most important function of which is the post-transcriptional negative regulation of gene expression. The study was aimed to investigate the mechanisms of the interactions between miRNA isoforms and ACE2/TMPRSS2 genes in the colon tissues known for the high level of expression of the described enzymes. The search for interactions was performed using the correlation analysis applied to the publicly available paired mRNA/miRNA sequencing data of colon tissues. Among the others, such miRNAs as miR-30c and miR-200c were identified known for their involvement in the coronavirus infection and acute respiratory distress syndrome pathogenesis. Thus, new potential mechanisms for the ACE2 and TMPRSS2 enzymes regulation were ascertained, as well as their possible functional activity in a cell infected with coronavirus.

LAMA4-Regulating miR-4274 and Its Host Gene SORCS2 Play a Role in IGFBP6-Dependent Effects on Phenotype of Basal-Like Breast Cancer

Specificity of RNAi to selected target is challenged by off-target effects, both canonical and non-canonical. Notably, more than half of all human microRNAs are co-expressed with hosting them proteincoding genes. Here we dissect regulatory subnetwork centered on IGFBP6 gene, which is associated with low proliferative state and high migratory activity of basal-like breast cancer. We inhibited expression of IGFBP6 gene in a model cell line for basal-like breast carcinoma MDA-MB-231, then traced secondary and tertiary effects of this knockdown to LAMA4, a laminin encoding gene that contributes to the phenotype of triple-negative breast cancer. LAMA4-regulating miRNA miR-4274 and its host gene SORCS2 were highlighted as intermediate regulators of the expression levels of LAMA4, which correlated in a basal-like breast carcinoma sample subset of TCGA to the levels of SORCS2 negatively. Overall, our study points that the secondary and tertiary layers of regulatory interactions are certainly underappreciated. As these types of molecular event may significantly contribute to the formation of the cell phenotypes after RNA interference based knockdowns, further studies of multilayered molecular networks affected by RNAi are warranted.

Detection of Low-Abundant MicroRNAs with Hybridization Microchips

The effect of low concentrations of miRNA on the ability of GeneChip miRNA 4.0 hybridization chips to evaluate their representation in the sample was studied. It is shown that the evaluation of the expression of 61 miRNAs is statistically significantly associated with the multiplicity of plasma dilution. Only 12 miRNAs showed very high Pearson correlation coefficient (>0.95) and they all decreased in response to dilution. High abundance of has-miR-4532 miRNA in plasma was demonstrated. This miRNA was never detected during sequencing of similar samples. It was concluded that in case of miRNA expression <1.12±0.33 units in log2 scale, dilution was not followed by further decrease in the signal intensity in GeneChip miRNA 4.0 chips.

Liquid biopsy: miRNA as a potential biomarker in oral cancer

Oral cancer is one of the leading cancers in South-Asian countries. Despite the easy access of the oral cavity, the detection and five year survival rates of OSCC patients are dismal. Identification of non-invasive biomarkers to determine the progression and recurrence of OSCC could be of immense help to patients. Recent studies on oral cancer suggest the importance of non-invasive biomarker development. Micro-RNAs (miRNAs) are one of the important components of the cell-free nucleic acids available in different body fluids. Here, we have reviewed the current understanding of circulating miRNAs as non-invasive biomarkers in different body fluids of oral cancer patients. A number of circulating miRNAs are found to be common in the body fluids of OSCC patients, while many of these are study specific, the possible sources of this variability could be due to differences in sample processing, assay procedure, clinical stage of the disease, oral habit and environmental factors. The prognostic and therapeutic significance of these circulating miRNAs are suggested by several studies. Mir-371, mir-150, mir-21 and mir-7d were found to be potential prognostic markers, while mir-134, mir-146a, mir-338 and mir-371 were associated with metastases. The prognostic markers, mir-21 and mir-7d were also found to be significantly correlated with resistance to chemotherapy, while mir-375, mir-196 and mir-125b were significantly correlated with sensitivity to radiotherapy. Despite the promising roles of circulating miRNAs, challenges still remain in unravelling the exact regulation of these miRNAs before using them for targeted therapy.

The presence of extracellular microRNAs in the media of cultured Drosophila cells

While regulatory RNA pathways, such as RNAi, have commonly been described at an intracellular level, studies investigating extracellular RNA species in insects are lacking. In the present study, we demonstrate the presence of extracellular microRNAs (miRNAs) in the cell-free conditioned media of two Drosophila cell lines. More specifically, by means of quantitative real-time PCR (qRT-PCR), we analysed the presence of twelve miRNAs in extracellular vesicles (EVs) and in extracellular Argonaute-1 containing immunoprecipitates, obtained from the cell-free conditioned media of S2 and Cl.8 cell cultures. Next-generation RNA-sequencing data confirmed our qRT-PCR results and provided evidence for selective miRNA secretion in EVs. To our knowledge, this is the first time that miRNAs have been identified in the extracellular medium of cultured cells derived from insects, the most speciose group of animals.

The expression profiling of serum miR-92a, miR-375, and miR-760 in colorectal cancer: An Egyptian study

Dysregulation in microRNA expression is a common feature in colorectal cancer. Due to the inconsistent results regarding serum miR-92a expression pattern and the insufficient studies on serum miR-375 and miR-760, we aimed in this study to investigate their expression profile and diagnostic and prognostic power in Egyptian colorectal cancer patients. The expression profile of miR-92a, miR-375, and miR-760 was determined in the sera of 64 colorectal cancer patients using quantitative real-time reverse transcription polymerase chain reaction in comparison to 27 healthy control subjects. The expression fold change of the studied microRNAs was correlated with patients' clinicopathological features. Receiver operating characteristic curve analysis was done to determine the role of these microRNAs in colorectal cancer diagnosis and follow-up according to the yielded area under the curve. The expression pattern of miR-92a was significantly upregulated (3.38 ± 2.52, p < 0.0001), while both of miR-375 and 760 were significantly downregulated (-1.250 ± 1.80, p< 0.0001; -1.710 ± 1.88, p < 0.0001, respectively) in colorectal cancer than the control. MiR-92a was positively correlated ( r = 0.671, p = 0.0001), while miR-375 and miR-760 were inversely correlated ( r = -0.414, p = 0.001; r = -0.644, p = 0.0001) with advanced colorectal cancer stages. Receiver operating characteristic curve analysis disclosed the highest diagnostic potential for miR-760 to discriminate colorectal cancer patients and early-stage colorectal cancer from the control (area under the curve = 0.922 and 0.875, respectively), while the highest prognostic potential for discrimination between colorectal cancer stages was for miR-92a. In conclusion, serum level of miR-92a, miR-375, and miR-760 may serve as biomarkers of colorectal cancer in Egyptian patients with high diagnostic power for miR-760 and high prognostic power for miR-92a.

Detection of Potential Metastatic Prostate Cancer Circulating Biomarkers by Comparison of miRNA Profiles in DU145 Cells and Culture Medium

We studied the profile of miRNA secreted into culture medium by DU145 prostate cancer cells and identified a subset of miRNAs characterized by the absence of correlation of their content in the cell and medium, which is likely a result of specific secretion. Three of these miRNA, hsa-miR-4417, hsa-miR-3175, and hsa-miR-6782-5p, exhibit the highest expression and are candidate circulating biomarkers for metastatic activity of prostate cancer. Two of these miRNA are coded by introns of genes linked with genome stability maintenance and chromatin remodeling regulation.

Circulating miRNAs from blood, plasma or serum as promising clinical biomarkers in oral squamous cell carcinoma: A systematic review of current findings

The purpose of this systematic review was to summarize current findings on the use of circulating miRNAs from blood, serum and plasma as cancer biomarkers in patients with oral squamous cell carcinoma. Studies were gathered after searching four different electronic databases: PUBMED, SCOPUS, Cochrane Library and Web of Science. Additional search was carried out through cross check on bibliography of selected articles. After the selection process made by two of the authors, 16 articles met the inclusion criteria and were included in the review. Results showed that circulating miRNAs from blood, serum or plasma represent promising candidates as cancer biomarkers in patients suffering from oral cancer. The possibility to predict recurrences and metastases through follow-up quantification of candidate miRNAs represents another potential feature to be addressed in future studies. However, methodological standardization and uniform sampling is needed to increase the power and accuracy of results.

Plasma Levels of hsa-miR-619-5p and hsa-miR-1184 Differ in Prostatic Benign Hyperplasia and Cancer

Peripheral blood plasma profiles of circulating microRNA expression were analyzed in patients with prostatic cancer and benign hyperplasia. In prostatic cancer, significant increase in hsa-miR-619-5p and hsa-miR-1184 microRNA expression and significant decrease in hsalet-7b-5p and hsa-let-7c-5p microRNA expression were observed. The role of the relationship between the microRNA expression and the activities and functions of host genes with introns encoding these microRNA is discussed.

MicroRNA hsa-miR-4674 in Hemolysis-Free Blood Plasma Is Associated with Distant Metastases of Prostatic Cancer

We analyzed microRNA profile in hemolysis-free blood plasma of patients with prostatic cancer. The metastatic form of prostatic cancer was found to be associated with increased levels of hsa-miR-22-3p, hsa-miR-663a, and hsa-miR-4674 in comparison with non-metastatic form. Common candidate target genes of these microRNA include JUNB, KMT2A, and XPO6.