Dual role of microRNA-31 in human cancers; focusing on cancer pathogenesis and signaling pathways.

Widespread changes in the expression of microRNAs in cancer result in abnormal gene expression for the miRNAs that control those genes, which in turn causes changes to entire molecular networks and pathways. The frequently altered miR-31, which is found in a wide range of cancers, is one cancer-related miRNA that is particularly intriguing. MiR-31 has a very complicated set of biological functions, and depending on the type of tumor, it may act both as a tumor suppressor and an oncogene. The endogenous expression levels of miR-31 appear to be a key determinant of the phenotype brought on by aberrant expression. Varied expression levels of miR-31 could affect cell growth, metastasis, drug resistance, and other process by several mechanisms like targeting BRCA1-associated protein-1 (BAP1), large tumor suppressor kinase 1 (LATS1) and protein phosphatase 2 (PP2A). This review highlights the current understanding of the genes that miR-31 targets while summarizing the complex expression patterns of miR-31 in human cancers and the diverse phenotypes brought on by altered miR-31 expression.

miR-31-5p suppresses myocardial hypertrophy by targeting Nfatc2ip.

Cardiac hypertrophy, worldwide known as an adaptive functional compensatory state of myocardial stress, is mainly believed to proceed to severe heart diseases, even to sudden death. Emerging studies have explored the microRNA alteration during hypertrophy. However, the mechanisms of microRNAs involved in cardiac hypertrophy are still uncertain. We studied young rats to establish abdominal aorta coarctation (AAC) for 4 weeks. With the significant downregulated cardiac function and upregulated hypertrophic biomarkers, AAC-induced rats showed enlarged myocardiocytes and alterations in microRNAs, especially downregulated miR-31-5p. miR-31-5p targets the 3'UTR of Nfatc2ip and inhibits myocardial hypertrophy in vitro and in vivo. Furthermore, we verified that Nfatc2ip is necessary and sufficient for cardiac hypertrophy in neonatal rat cardiomyocytes. Moreover, we found miR-31-5p inhibited the colocalization of Nfatc2ip and hypertrophic gene ß-Mhc. Luciferase assay and ChiP-qPCR test demonstrated that Nfatc2ip binded to the core-promoter of ß-Mhc and enhanced its transcriptional activity. Above all, our study found a new pathway, mir-31-5p/Nfatc2ip/ß-Mhc, which is involved in cardiac hypertrophy, suggesting a potential target for intervention of cardiac hypertrophy.

A peptide encoded by pri-miRNA-31 represses autoimmunity by promoting Treg differentiation.

Recent evidence has revealed that small polypeptides (containing fewer than 100 amino acids) can be translated from noncoding RNAs (ncRNAs), which are usually defined as RNA molecules that do not encode proteins. However, studies on functional products translated from primary transcripts of microRNA (pri-miRNA) are quite limited. Here, we describe a peptide termed miPEP31 that is encoded by pri-miRNA-31. miPEP31 is highly expressed in Foxp3+ regulatory T cells (Tregs ) and significantly promotes the differentiation of Tregs without affecting their inhibitory ability. Our results show that miPEP31 is a cell-penetrating peptide both in vitro and in vivo. miPEP31 downregulates miR-31 expression, enhances peripheral Treg induction, and dramatically suppresses experimental autoimmune encephalomyelitis. Mechanistically, we show that miPEP31 acts as a transcriptional repressor inhibiting the expression of miRNA-31, a negative regulator of Tregs . Our results reveal an indispensable role of miPEP31 in maintaining immune homeostasis by promoting Treg differentiation and also present a potential therapeutic peptide for modulating miRNA expression and treating autoimmune diseases.

MiR-31-5p alleviates septic cardiomyopathy by targeting BAP1 to inhibit SLC7A11 deubiquitination and ferroptosis.

Septic cardiomyopathy is one of the most severe and common complications in patients with sepsis and poses a great threat to their prognosis. However, the potential mechanisms and effective therapeutic drugs need to be explored. The control of cardiac cell death by miRNAs has emerged as a prominent area of scientific interest in the diagnosis and treatment of heart disorders in recent times. In the present investigation, we discovered that overexpression of miR-31-5p prevented LPS-induced damage to H9C2 cells and that miR-31-5p could inhibit BAP1 production by binding to its 3'-UTR. BRCA1-Associated Protein 1 (BAP1) is a ubiquitin carboxy-terminal hydrolase. BAP1 upregulation blocked effect of miR-31-5p on H9C2 cell injury. Moreover, BAP1 inhibited the expression of solute carrier family 7 member 11 (SLC7A11) by deubiquitinating histone 2 A (H2Aub) on the promoter of SLC7A11. Furthermore, overexpression of miR-31-5p and downregulation of BAP1 inhibited SLC7A11 mediated ferroptosis. In addition, the downregulation of SLC7A11 reversed the inhibitory effect of miR-31-5p on the expression of myocardial injury and inflammatory factors, and cell apoptosis was reversed. In conclusion, these results indicate that miR-31-5p alleviates malignant development of LPS-induced H9C2 cell injury by targeting BAP1 and regulating SLC7A11 deubiquitination-mediated ferroptosis, which confirmed the protective effect of miR-31-5p on H9C2 cell injury and revealed potential mechanisms that may provide new targets for treatment of septic cardiomyopathy.

LncRNA NEAT1 accelerates renal fibrosis progression via targeting miR-31 and modulating RhoA/ROCK signal pathway.

Renal fibrosis is the final pathway for chronic kidney disease to end-stage renal failure. Noncoding RNAs have been reported to play a crucial role in renal fibrosis. Here, the effects of long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) and miR-31 on renal fibrosis and their regulatory mechanism were evaluated. RT-qPCR was used to assess NEAT1, miR-31, and RhoA levels. Western blot was performed to analyze the expression of fibrosis markers, RhoA, rho-related kinase (ROCK1), and connective tissue growth factor (CTGF). RNA immunoprecipitation (RIP), fluorescence in situ hybridization (FISH), and luciferase reporter assays verified the interaction between miR-31 and NEAT1 or RhoA. Renal fibrosis and injury were observed by Masson and hematoxylin and eosin (H&E) staining. The expression level of inflammatory cytokines was detected by ELISA. Immunohistochemistry (IHC) was performed to examine the expression levels of α-smooth muscle actin (α-SMA) and RhoA in renal tissues. We showed that NEAT1 was highly expressed, whereas miR-31 was decreased in renal fibrosis. NEAT1 was found to directly bind miR-31 to positively regulate RhoA expression. Furthermore, NEAT1 silencing inhibited renal fibrosis and inflammation and suppressed the RhoA/ROCK1 signaling pathway. However, knockdown of miR-31 could reverse these effects. NEAT1 silencing or overexpression of miR-31 alleviated renal fibrosis in vivo. In conclusion, NEAT1 accelerates renal fibrosis progression via negative regulation of miR-31 and the activation of RhoA/ROCK1 pathway, thereby upregulating the expression level of CTGF, providing a theoretical basis for treatment and prognostic evaluation of renal fibrosis.

MicroRNA-31 regulates TNF-α and IL-17A co-induced-endothelial cell apoptosis by repressing E2F6.

Vascular endothelial cell (VEC) apoptosis is the fundamental cause of pulmonary arterial hypertension. MicroRNA-31 (MiR-31) is a novel target for hypertension treatment. However, the role and mechanism of miR-31 in the apoptosis of VECs remain unclear. The purpose of this study is to determine whether miR-31 plays an important role in VEC apoptosis as well as the detailed mechanisms involved. We found that pro-inflammatory cytokines IL-17A and TNF-α were highly expressed in serum and aorta, and the expression of miR-31 was significantly increased in aortic intimal tissue from Angiotensin II (AngII)- induced hypertensive mice (WT-AngII) compared with control mice (WT-NC). In vitro, co-stimulation of VECs with IL-17A and TNF-α resulted in increased expression of miR-31 and VEC apoptosis. MiR-31 inhibition strikingly decreased TNF-α and IL-17A co-induced VEC apoptosis. Mechanistically, in IL-17A and TNF-α co-stimulated VECs (co-induced VECs), we found that the activation of the NF-κB signal effectively increased the expression of miR-31. Dual-luciferase reporter gene assay revealed that miR-31 directly targeted and inhibited the expression of the E2F transcription factor 6 (E2F6). The expression of E2F6 was decreased in Co-induced VECs. MiR-31 inhibition significantly alleviated the decreased expression of E2F6 in co-induced VECs. Consistent with the co-stimulated effect of IL-17A and TNF-α on VECs, transfection of siRNA E2F6 induced cell apoptosis without the stimulation of the above cytokines. In conclusion, TNF-α and IL-17A generated in the aortic vascular tissue and serum from Ang II-induced hypertensive mice could trigger VECs apoptosis by the miR-31/E2F6 axis. To sum up, our study suggests that the key factor between cytokine co-stimulation effect and VEC apoptosis was miR-31/E2F6 axis, which was mainly regulated by NF-қB signaling pathway. This gives us a new sight to treat hypertension-associated VR.

Exosomal lncRNA Mir100hg derived from cancer stem cells enhance glycolysis and promote metastasis of lung adenocarcinoma through mircroRNA-15a-5p/31-5p.

BACKGROUND: Exosomes are a new class of molecular entities in the metastatic microenvironment, which can mediate bidirectional communication between cells. While exosomes-mediated interactions between tumor cells and other cell populations in the tumor microenvironment have attracted most attention, little is known about the significance of exosomes in mediating the interaction between non-stemness cancer cells and cancer stem cells during cancer progression. METHODS: The structure, sequence and downstream target miRNAs of lncRNA Mir100hg were predicted by online web resources. The bioinformatics prediction results were validated with experimental verification: exosome tracing, electron microscopy, Luciferase assay, metabolomics sequencing and mouse tail vein model of pulmonary metastasis. A complex regulatory network of "cancer stem cells-exosomal lncRNA-non-stem cancer cells" was constructed. RESULTS: This study demonstrates firstly that lncRNA Mir100hg is upregulated in lung cancer stem cell LLC-SD (Lung cancer stem cells) and can be delivered to non-stemness cancer cells LLC (Lewis lung cancer cells) via exosomes. In LLC, Mir100hg targets miR-15a-5p and miR-31-5p which leads to the increase of the global glycolytic activity of lung cancer cells and consequently, the enhancement of their metastatic capability. CONCLUSION: We delineated a complex regulatory network that utilized by cancer stem cells to transfer their high metastatic activity to the low-metastatic non-stemness cancer cells through exosomal Mir100hg, thereby providing new mechanistic insights into the communication between two heterogeneous tumor cells. Video Abstract.

Impact of MIR31HG polymorphisms on risk of breast cancer in Chinese women.

BACKGROUND: Breast cancer (BC) is one of the leading causes of death worldwide. This study explored the relationship between the MIR31HG gene polymorphisms and the risk of BC in Chinese women. METHODS: Eight single nucleotide polymorphisms (SNPs) in MIR31HG were genotyped among 545 patients with BC and 530 healthy controls using Agena MassARRAY analysis. The PLINK software was used to calculate the odds ratio (OR) and 95% confidence intervals (CIs) via the logistic regression analysis. Multi-factor dimensionality reduction (MDR) analysis was performed to study the impact of SNP-SNP interaction on BC risk. RESULTS: MIR31HG rs72703442-AA (OR 0.29, 95% CI 0.10-0.79, p = 0.026), rs55683539-TT (OR 0.46, 95% CI 0.26-0.80, p = 0.012) and rs2181559-AA (OR 0.59, 95% CI 0.40-0.89, p = 0.038) were associated with a reduced risk of BC in Chinese women, as well as stratified results at age ≥ 52 years. Rs79988146 was correlated with estrogen receptor (ER) and progesterone receptor (PR)in Chinese female BC patients under various genetic models. Age at menarche stratification indicated that rs1332184 was associated with increased risk in BC patients, whereas stratification by number of births indicated that rs10965064 was associated with reduced risk in BC patients. MDR analysis showed that the best single-locus model for predicting of BC risk are rs55683539, which, rs55683539-CC group was a high risk group and rs55683539-TT group was a low risk group. CONCLUSIONS: The results indicated that the MIR31HG polymorphisms were associated with a reduced risk of BC in Chinese women.

Meta-signature guided investigation of miRNA candidates as potential biomarkers of oral cancer.

OBJECTIVES: This study aimed to experimentally validate dysregulated expression of miRNA candidates selected through updated meta-analysis of most commonly deregulated miRNAs in oral cancer and to explore their diagnostic and prognostic potential. MATERIALS AND METHODS: Five miRNAs (miR-31-3p, miR-135b-5p, miR-18a-5p, miR-30a-5p and miR-139-5p) from updated meta-signature were selected for validation by qRT-PCR method in 35 oral cancer clinical specimens and adjacent non-cancerous tissue. RESULTS: Updated meta-analysis has identified 13 most commonly deregulated miRNAs in oral cancer. Seven miRNAs were consistently up-regulated (miR-21-5p, miR-31-3p, miR-135b-5p, miR-31-5p, miR-424-5p, miR-18a-5p and miR-21-3p), while five were down-regulated (miR-139-5p, miR-30a-3p, miR-375-3p, miR-376c-3p and miR-30a-5p). Increased expression of miR-31-3p and miR-135b-5p, and decreased expression of miR-139-5p and miR-30a-5p were confirmed in oral cancer compared to adjacent non-cancerous tissue. A three miRNAs combination (miR-31-3p, miR-139-5p and miR-30a-5p) gave the most promising diagnostic potential for discriminating oral cancer from non-cancerous tissue (AUC: 0.780 [95% CI: 0.673-0.886], p < 0.0005, sensitivity 94.3%, specificity 51.4%). High expression of miR-135b-5p, miR-18a-5p and miR-30a-5p was associated with poor survival (p = 0.003, p = 0.048, p = 0.016 respectively). CONCLUSION: miR-31-3p, miR-139-5p and miR-30a-5p panel was confirmed as a potential diagnostic biomarker when distinguishing oral cancer from non-cancerous tissue. miR-135b-5p, miR-18a-5p and miR-30a-5p might serve as potential biomarkers of poor survival of oral cancer patients.

Intermittent hypoxia BMSCs-derived exosomal miR-31-5p promotes lung adenocarcinoma development via WDR5-induced epithelial mesenchymal transition.

BACKGROUND: Intermittent hypoxia (IH) is a factor involved in the incidence and progression of lung adenocarcinoma (LUAD). Bone marrow-derived bone mesenchymal stem cells (BMSCs)-derived exosomes are related to the promotion of tumor development. The objective of this experiment was to clarify the mechanism of exosomes from BMSCs in promoting the progression of LUAD induced by IH. METHODS: This study examined if IH BMSCS-derived exosomes affect the malignancy of LUAD cells in vitro. Dual-luciferase assays were conducted to confirm the target of miR-31-5p with WD repeat domain 5 (WDR5). We further investigated whether or not  exosomal miR-31-5p or WDR5 could regulate epithelial-mesenchymal transition (EMT). We determined the effect of IH exosomes using a tumorigenesis model in vivo. RESULTS: miR-31-5p entered into LUAD cells via exosomes. MiR-31-5p was greatly upregulated in IH BMSCs-derived exosomes compared with RA exosomes. Increased expression of exosomal miR-31-5p induced by IH was discovered to target WDR5 directly, increased activation of WDR5, and significantly facilitated EMT, thereby promoting LUAD progression. CONCLUSIONS: The promoting effect of IH on LUAD is achieved partly through BMSCs-derived exosomal miR-31-5p triggering WDR5 and promoting EMT.

Abrogation of esophageal carcinoma development in miR-31 knockout rats.

MicroRNA-31 (miR-31) is overexpressed in esophageal squamous cell carcinoma (ESCC), a deadly disease associated with dietary Zn deficiency and inflammation. In a Zn deficiency-promoted rat ESCC model with miR-31 up-regulation, cancer-associated inflammation, and a high ESCC burden following N-nitrosomethylbenzylamine (NMBA) exposure, systemic antimiR-31 delivery reduced ESCC incidence from 85 to 45% (P = 0.038) and miR-31 gene knockout abrogated development of ESCC (P = 1 × 10-6). Transcriptomics, genome sequencing, and metabolomics analyses in these Zn-deficient rats revealed the molecular basis of ESCC abrogation by miR-31 knockout. Our identification of EGLN3, a known negative regulator of nuclear factor κB (NF-κB), as a direct target of miR-31 establishes a functional link between oncomiR-31, tumor suppressor target EGLN3, and up-regulated NF-κB-controlled inflammation signaling. Interaction among oncogenic miR-31, EGLN3 down-regulation, and inflammation was also documented in human ESCCs. miR-31 deletion resulted in suppression of miR-31-associated EGLN3/NF-κB-controlled inflammatory pathways. ESCC-free, Zn-deficient miR-31-/- rat esophagus displayed no genome instability and limited metabolic activity changes vs. the pronounced mutational burden and ESCC-associated metabolic changes of Zn-deficient wild-type rats. These results provide conclusive evidence that miR-31 expression is necessary for ESCC development.

Circular RNA hsa_circ_0000175 Serves as a Potential Biomarker for Rheumatoid Arthritis via miR-31-5p/GSDME Axis.

Rheumatoid arthritis (RA) is a common inflammatory autoimmune disease characterized by synovial inflammation and joint damage. Previous studies have shown that pyroptosis plays an important role in the pathogenesis of RA. In this study, the effects of circular RNA hsa_circ0000175 on pyroptosis and inflammation of RA were evaluated. Serum levels of circ_0000175 and miR-31-5p were determined by RT-qPCR, and the correlation between them was evaluated by Spearman correlation analysis. Fibroblast-like synoviocytes (FLSs) were extracted and prepared for in vitro study. The subcellular localization of circ_0000175 was detected by FISH assay. Pyroptosis and inflammatory cytokines interleukin (IL)-1ß, IL-18 and IL-6 were measured by flow cytometry and ELISA, respectively. RNA pull-down and luciferase reporter assays verified the interaction between circ_0000175 and miR-31-5p. Western blot was used to detect the differential expression of pyroptosis-related factors (GSDME-N, GSDMD-N, cleaved caspase-1 and cleaved caspase-3). Circ_0000175 level was increased but miR-31-5p expression was decreased in PBMCs of RA patients and LPS/ATP-treated FLSs, companied with negative correlation. Moreover, miR-31-5p was a target of circ_0000175 in RA-FLSs. Silencing of circ_0000175 or overexpression of miR-31-5p significantly alleviated LPS/ATP-induced pyroptosis in FLSs through both caspase-1/GSDMD and caspase-3/GSDME pathways. Additionally, GSDME was identified as the target of miR-31-5p. The inhibitory effects of circ_0000175 depletion on pyroptosis and inflammation in RA-FLSs treated with LPS/ATP were strengthened by GSDME knockdown. Circ_0000175 can induce pyroptosis and trigger inflammatory response during the occurrence of RA through the miR-31-5p/GSDME axis, which provides a novel therapeutic target for RA treatment.

LncRNA SNHG16 Knockdown Promotes Diabetic Foot Ulcer Wound Healing via Sponging MiR-31-5p.

Diabetic foot ulcers are caused by nerve abnormalities and vascular lesions in the distal lower limbs of diabetic patients. However, the causes of diabetic foot ulcers are diverse and the treatment process is complex. Therefore, understanding the pathogenesis of diabetic foot ulcers through lncRNA and formulating effective means are the key to the cure of patients. Tissues were collected from 76 diabetic foot ulcer patients and 50 non-diabetic patients undergoing traumatic amputation. Human dermal fibroblasts (HDFs) were induced by high glucose to obtain diabetic foot ulcer cell model. The lncRNA SNHG16 (SNHG16) and miR-31-5p expression in tissues and cells was detected by real-time quantitative reverse transcription PCR (RT-qPCR). Cell Counting Kit-8 (CCK-8) and Transwell assays were used to evaluate the biological behavior of the cells, and the association between SNHG16 and miR-31-5p was explored by luciferase reporting assay. SNHG16 was distinctly expressed in diabetic foot ulcer tissue samples, while miR-31-5p was decreased. In vitro cell function assays confirmed that the proliferation level was inhibited in the constructed diabetic foot ulcer cell model (HG group), as was the migration and invasion ability. After transfection with silencing SNHG16, the biological behavior of the cells was promoted. Mechanistically, SNHG16 sponge miR-31-5p regulated disease progression. Recovery experiments revealed that miR-31-5p inhibitor counteracted the effect of silencing SNHG16 on cell viability. SNHG16 knockdown may regulate the biological function of cells by targeting miR-31-5p to promote wound healing and ameliorate the condition of diabetic foot ulcer patients.

Analysis of the Promoter Regions of gga-miR-31 and Its Regulation by RA and C-jun in Chicken.

The role of gga-miR-31 in chicken germ cell differentiation and spermatogenesis is of significant importance. The transcriptional properties of gga-miR-31 are crucial in establishing the foundation for the formation of chicken spermatogonia stem cells and spermatogenesis. In this study, a series of recombinant vectors including varying lengths of the gga-miR-31 promoter were predicted and constructed. Through the utilization of the dual luciferase reporting system, the upstream -2180~0 bp region of gga-miR-31 was identified as its promoter region. Furthermore, it was predicted and confirmed that the activity of the gga-miR-31 promoter is increased by retinoic acid (RA). The binding of RA to the gga-miR-31 and Stra8 promoter regions was found to be competitive. Through the deletion of C-jun binding sites and the manipulation of C-jun expression levels, it was determined that C-jun inhibits the activity of the gga-miR-31 promoter. Furthermore, the combined treatment of C-jun and RA demonstrated that the positive regulatory effect of RA on the gga-miR-31 promoter is attenuated in the presence of high levels of C-jun. Overall, this study establishes a foundation for further investigation into the regulatory mechanisms of gga-miR-31 action, and provides a new avenue for inducing chicken embryonic stem cells (ESC) to differentiate into spermatogonial stem cells (SSC), and sperm formation.

Serum and Saliva Level of miR-31-5p and miR-let 7a in EBV Associated Oropharyngeal Cancer.

Epstein-Barr virus (EBV) has a well-documented association with head and neck neoplasms, including nasopharyngeal carcinoma (NPC). In the last few years, research aimed at elucidating the role of the miRs in the pathogenesis of head and neck cancer (HNC) has gained importance. The study of miRs expression has set new directions in the search for biomarkers with diagnostic and prognostic value, and even in the search for new therapeutic targets for various tumors, including HNC. The aim of current study was to approximate the importance of miR-31-5p and miR-let 7a in the pathogenesis of EBV associated oropharyngeal cancer. For this purpose, experiments were carried out to determine the level of mentioned miRs in serum among patients diagnosed with oropharyngeal cancer linked to EBV infection, depending on histological differentiation-grading (G1-G3) and TNM classification. All clinical specimens stratified by HPV status were HPV negative. The level of antibodies EBNA and EBVCA was also assessed. The obtained results showed a significantly increased serum level of miR-31-5p but decreased level of miR-let 7a in EBV positive oropharyngeal cancer patients. We demonstrated association between the level of tested miRs and clinical stage. Our findings showed that miR-31-5p and miR-let-7a may be involved in development and progression of EBV associated oropharyngeal cancer. Therefore, it seems important to further study these molecules, as well as to determine whether they could be important biomarkers in the diagnosis of oropharyngeal cancer associated with EBV infection.

Diosmin nanocrystal gel alleviates imiquimod-induced psoriasis in rats via modulating TLR7,8/NF-κB/micro RNA-31, AKT/mTOR/P70S6K milieu, and Tregs/Th17 balance.

Diosmin is a flavonoid with promising anti-inflammatory and antioxidant properties. However, it has difficult physicochemical characteristics since its solubility demands a pH level of 12, which has an impact on the drug's bioavailability. The aim of this work is the development and characterization of diosmin nanocrystals using anti-solvent precipitation technique to be used for topical treatment of psoriasis. Results revealed that diosmin nanocrystals stabilized with hydroxypropyl methylcellulose (HPMC E15) in ratio (diosmin:polymer; 1:1) reached the desired particle size (276.9 ± 16.49 nm); provided promising colloidal properties and possessed high drug release profile. Additionally, in-vivo assessment was carried out to evaluate and compare the activities of diosmin nanocrystal gel using three different doses and diosmin powder gel in alleviating imiquimod-induced psoriasis in rats and investigating their possible anti-inflammatory mechanisms. Herein, 125 mg of 5% imiquimod cream (IMQ) was applied topically for 5 consecutive days on the shaved backs of rats to induce psoriasis. Diosmin nanocrystal gel especially in the highest dose used offered the best anti-inflammatory effect. This was confirmed by causing the most statistically significant reduction in the psoriasis area severity index (PASI) score and the serum inflammatory cytokines levels. Furthermore, it was capable of maintaining the balance between T helper (Th17) and T regulatory (Treg) cells. Moreover, it tackled TLR7/8/NF-κB, miRNA-31, AKT/mTOR/P70S6K and elevated the TNFAIP3/A20 (a negative regulator of NF-κB) expression in psoriatic skin tissues. This highlights the role of diosmin nanocrystal gel in tackling imiquimod-induced psoriasis in rats, and thus it could be a novel promising therapy for psoriasis.

miR-31-5p/SOX4 Axis Affects Autophagy and Apoptosis of Chondrocytes by Regulating Extracellular Regulated Protein Kinase/Mechanical Target of Rapamycin Kinase Signalling.

BACKGROUND: Osteoarthritis (OA) is a common type of degenerative joint diseases that is regulated by a combination of complex intercellular signals and modulators, including non-coding RNAs. Mounting evidence suggests that miR-31-5p is physiologically involved in the regulation of chondrocytes, but the mechanism remains unclear. METHODS: Expression levels of miR-31-5p and SOX4 in OA cartilage tissues and in IL-1ß-stimulated chondrocytes were examined by quantification polymerase chain reaction (q-PCR) or immunohistochemistry assays. Cell proliferation and apoptosis were detected by Cell Counting Kit-8 (CCK-8) and flow cytometry assays, respectively. Expression of LC3 was detected using immunofluorescence staining. Expressions of autophagy-related proteins and extracellular regulated protein kinase (ERK)/mechanical target of rapamycin kinase (mTORC1) signal-related proteins were measured by Western blot analysis. Molecular interaction was validated by dual luciferase reporter assay. RESULTS: Downregulation of miR-31-5p and upregulation of SOX4 were observed in both OA patients and OA chondrocytes. Mechanistic experiments revealed that miR-31-5p negatively modulated SOX4 expression by directly targeting its 3'- untranslated region. Moreover, overexpression of miR-31-5p suppressed the activation of mTORC1 in an ERK-dependent manner by inhibiting SOX4. Further functional experiments demonstrated that overexpressing miR-31-5p in OA chondrocytes markedly promoted its proliferation and autophagy while inhibiting apoptosis. However, these effects were abolished by overexpression of SOX4 or treatment with 3BDO, an mTOR activator. CONCLUSION: These results demonstrated that miR-31-5p enhanced survival and autophagy of OA chondrocytes through inactivation of mTORC1 via directly targeting SOX4, suggesting that miR-31-5p may play a protective role in OA progression.

Circ-POLR3A accelerates TGF-ß2-induced promotion in cell viability, migration, and invasion of lens epithelial cells via miR-31/TXNIP signaling cascade.

Posterior capsular opacification (PCO) is the major complication after cataract surgery and can result in secondary vision loss. Circular RNAs (circRNAs) are reported to play critical regulatory roles in multiple cell biological processes. The most common working mechanism of circRNAs is by acting as microRNA sponges. Here, we analyzed the role and mechanism of circRNA RNA polymerase III subunit A (POLR3A) in PCO. Cell viability was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell motility was assessed by transwell and wound healing assays. Dual-luciferase reporter and RNA-pull-down assays were performed to verify the interaction between microRNA-31 (miR-31) and circ-POLR3A or thioredoxin interacting protein (TXNIP). PCO cell model was established by treating SRA01/04 cells with transforming growth factor-ß2 (TGF-ß2). We found that TGF-ß2 enhanced SRA01/04 cell viability, migration, and invasion abilities. Circ-POLR3A expression was upregulated in PCO tissues and TGF-ß2-induced SRA01/04 cells. TGF-ß2 promoted the viability and motility of SRA01/04 cells largely by upregulating circ-POLR3A. Circ-POLR3A negatively regulated the miR-31 level by directly interacting with it. Circ-POLR3A absence-induced influences in TGF-ß2-induced SRA01/04 cells were partly reversed by silencing miR-31. miR-31 is directly bound to the 3'-untranslated region of TXNIP. TXNIP overexpression largely attenuated miR-31 overexpression-mediated effects in TGF-ß2-induced SRA01/04 cells. Circ-POLR3A could elevate the protein expression of TXNIP by sponging miR-31. Exosomes were involved in mediating the delivery of circ-POLR3A in SRA01/04 cells. In conclusion, circ-POLR3A contributed to TGF-ß2-induced promotion of cell viability, migration, and invasion of SRA01/04 cells by targeting miR-31/TXNIP axis.

Suppression of MIR31HG affects the functional properties of thyroid cancer cells depending on the miR-761/MAPK1 axis.

BACKGROUND: Thyroid cancer is the most prevalent endocrine malignancy. Long non-coding RNA (lncRNA) MIR31HG is abnormally expressed in thyroid cancer tissues. However, the precise, critical role of MIR31HG in thyroid cancer development remains unclear. METHODS: MIR31HG, microRNA (miR)-761 and mitogen-activated protein kinase 1 (MAPK1) were quantified by quantitative real-time PCR (qRT-PCR) and immunoblotting. Cell viability, proliferation, apoptosis, invasion and migration abilities were evaluated by MTS, 5-Ethynyl-2'-Deoxyuridine (EdU), flow cytometry, transwell and wound-healing assays, respectively. Dual-luciferase reporter assays were used to validate the direct relationship between miR-761 and MIR31HG or MAPK1. RESULTS: MIR31HG was overexpressed in human thyroid cancer, and its overexpression predicted poor prognosis. Suppression of MIR31HG impeded cell proliferation, invasion and migration, as well as promoted cell apoptosis in vitro, and diminished the growth of xenograft tumors in vivo. Mechanistically, MIR31HG targeted and regulated miR-761. Moreover, miR-761 was identified as a molecular mediator of MIR30HG function in regulating thyroid cancer cell behaviors. MAPK1 was established as a direct and functional target of miR-761 and MAPK1 knockdown phenocopied miR-761 overexpression in impacting thyroid cancer cell behaviors. Furthermore, MIR31HG modulated MAPK1 expression by competitively binding to miR-761 via the shared binding sequence. CONCLUSION: Our findings demonstrate that MIR31HG targets miR-761 to regulate the functional behaviors of thyroid cancer cells by upregulating MAPK1, highlighting a strong rationale for developing MIR31HG as a novel therapeutic target against thyroid cancer.

miR-31-5p promotes proliferation and inhibits apoptosis of goat hair follicle stem cells by targeting RASA1/MAP3K1 pathway.

The Yangtze River Delta white goat is a sole goat species that can naturally produce superior-quality brush hair. It's worth to mention that study the developmental mechanism of goat hair follicle stem cells is vital for future breed preservation and molecular breeding. In this study, we successfully isolated hair follicle stem cells from the skin tissue of fetal sheep neck spine, and harvested superior-quality and normal-quality brush hair goat tissue. The expression of miR-31-5p in goat hair follicle stem cells was verified by qPCR and Western blot. The effects of overexpression or inhibition of miR-31-5p on the proliferation and apoptosis of hair follicle stem cells were detected by EdU, CCK-8, flow cytometry, etc. miR-31-5p can significantly improve cell proliferation and inhibit cell apoptosis by targeting RASA1 and upregulating MAP3K1 level, whereas miR-31-5p knockdown led to an opposite effect. These results reveal a miR-31-5p-associated regulatory network between miR-31-5p and RASA1/MAP3K1 during the progression of superiorquality brush hair traits.