Regulatory role of microRNAs on PTEN signaling

LncRNA HOTAIR influences cell proliferation via miR-130b/PTEN/AKT axis in IDD

Intervertebral disc degeneration (IDD) constitutes the pathological foundation of most musculoskeletal disorders of the spine. Previous studies have noted that cell proliferation is a common feature of IDD. Bioinformatics indicated that aberrantly expressed long non-coding RNAs (lncRNAs) were involved in the development of IDD. In this study, we aimed to investigate the function of lncRNA HOTAIR in the proliferation of human nucleus pulposus (NP) cells of IDD in vitro and further clarified its mechanism. The expression of HOTAIR and miR-130b was quantified by qRT-PCR in nucleus pulposus (NP) tissues. Furthermore, NP cells proliferation were assayed by CCK8 and Immunostaining. Dual-luciferase reporter and RIP assay were used to examine the expression of HOTAIR, PTEN, and their co-target gene miR-130b. Western blotting was used to test AKT expression. Our in vitro experiments on human normal NP cells observed that HOTAIR was significantly dysregulated in IDD. Further, HOTAIR can suppress proliferation by directly targeting miR-130b. In addition, Both HOTAIR and PTEN were confirmed to target miR-130b, and miR-130b upregulation reversed the phenomenon of ectopic expression of HOTAIR. More importantly, HOTAIR upregulation significantly reduced CyclinD1 protein expression by PTEN/AKT signaling pathway. Our findings suggest that HOTAIR may bind to miR-130b and subsequently increased CyclinD1 expression via PTEN/Akt pathway. Thereby, HOTAIR could become a potential target for the treatment of IDD.Abbreviations : IDD; intervertebral disc degeneration ncRNAs; non-coding RNAs lncRNAs; long non-coding RNAs miRNAs; microRNAs NP; nucleus pulposus qRT-PCR; quantitative reverse transcription-PCR LBP; Low back pain ORF; open reading frame HOTAIR; Hox transcript antisense intergenic RNA FAF1; Fas-associated protein factor-1 Erk; extracellular signal-regulated kinase TUG1; Taurine Up-regulated Gene 1 HIF1A hypoxia-inducible factor 1-alpha PI3K; phosphoinositide-3 kinase AIS; adolescent idiopathic scoliosis ECM; extracellular matrix LN;lupus nephritis CT;computed tomography MRI; magnetic resonance imaging PBS; phosphate-buffered salin PBS; phosphate-buffered salin PVDF; polyvinylidene fluoride TBST; Tris-buffered saline Tween ECL; enhanced chemiluminescence RIP; RNA immunoprecipitation.

Long Non-Coding RNA in Gastric Cancer: Mechanisms and Clinical Implications for Drug Resistance

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide, with high recurrence and mortality rate. Chemotherapy, including 5-fluorouracil (5-FU), adriamycin (ADR), vincristine (VCR), paclitaxel (PTX), and platinum drugs, remains one of the fundamental methods of GC treatment and has efficiently improved patients’ prognosis. However, most patients eventually develop resistance to chemotherapeutic agents, leading to the failure of clinical treatment and patients’ death. Recent studies suggest that long non-coding RNAs (lncRNAs) are involved in the drug resistance of GC by modulating the expression of drug resistance-related genes via sponging microRNAs (miRNAs). Moreover, lncRNAs also play crucial roles in GC drug resistance via a variety of mechanisms, such as the regulation of the oncogenic signaling pathways, inhibition of apoptosis, induction of autophagy, modulation of cancer stem cells (CSCs), and promotion of the epithelial-to-mesenchymal transition (EMT) process. Some of lncRNAs exhibit great potential as diagnostic and prognostic biomarkers, as well as therapeutic targets for GC patients. Therefore, understanding the role of lncRNAs and their mechanisms in GC drug resistance may provide us with novel insights for developing strategies for individual diagnosis and therapy. In this review, we summarize the recent findings on the mechanisms underlying GC drug resistance regulated by lncRNAs. We also discuss the potential clinical applications of lncRNAs as biomarkers and therapeutic targets in GC.

Highlighting the interplay of microRNAs from Leishmania parasites and infected-host cells

Leishmania parasites, the causative agents of leishmaniasis, are protozoan parasites with the ability to modify the signalling pathway and cell responses of their infected host cells. These parasite strategies alter the host cell environment and conditions favouring their replication, survival and pathogenesis. Since microRNAs (miRNAs) are able to post-transcriptionally regulate gene expression processes, these biomolecules can exert critical roles in controlling Leishmania-host cell interplay. Therefore, the identification of relevant miRNAs differentially expressed in Leishmania parasites as well as in infected cells, which affect the host fitness, could be critical to understand the infection biology, pathogenicity and immune response against these parasites. Accordingly, the current review aims to address the differentially expressed miRNAs in both, the parasite and infected host cells and how these biomolecules change cell signalling and host immune responses during infection. A deep understanding of these processes could provide novel guidelines and therapeutic strategies for managing and treating leishmaniasis.

MiR-499a prevents astrocytes mediated inflammation in ischemic stroke by targeting PTEN

INTRODUCTION

Ischemic stroke (IS) is a common and severe neurological disorder and is associated with high rates of mortality and morbidity. Inflammatory reaction in astrocytes is one of the important pathological factors of stroke. Improved understanding of the underlying molecular mechanisms should aid better treatment of the disease. This study aimed to test our hypothesis that a miR-499a played an important role in the inflammatory response in astrocytes induced by IS targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN).

METHODS

This study was comprised of two models: oxygen-glucose deprivation (OGD) and reoxygenation model. Quantitative real-time PCR (qRT-PCR) and Western blot were used to examine gene expression levels, and MTT assay analysis were used to examine cell states. The relationships between miR-499a and PTEN were confirmed by luciferase reporter assay.

RESULTS

MiR-499a was robustly downregulated with OGD induced injury in astrocytes. Forced transient expression of miR-499a in OGD astrocytes nearly completely reversed the inflammatory response. Knockdown of miR-499a by its specific inhibitor in healthy astrocytes induced the inflammatory response resembling those produced by OGD. On the other hand, PTEN was markedly upregulated in OGD astrocytes, which was reciprocal to the expression of miR-499a. PTEN was experimentally validated as a direct target gene for miR-499a. Overexpression of PTEN was able to induce an inflammatory response of astrocytes. Moreover, PTEN siRNA counteracted the inflammatory response induced by OGD.

CONCLUSIONS

Taken together, our findings indicate miR-499a as an important factor to prevent inflammatory response and suggest miR-499a as a new molecule for the treatment of IS. The present study also demonstrated the relationship between miR-499a and PTEN, with PTEN as a downstream signaling mediator of miR-499a in the inflammatory response of astrocytes induced by IS.

Expression of miR-1-3p, miR-16-5p and miR-122-5p as Possible Risk Factors of Secondary Cardiovascular Events

Ischemic event in one arterial territory increases the risk of a subsequent ischemic event. Circulating microRNAs (miRs) emerge as a potential clinical tool to assess risk of subsequent atherothrombotic events such as cardiovascular death (CVD), myocardial infarction (MI) and ischemic stroke (IS). In this prospective study, we searched for athero-specific miRs related to cardiovascular event risk in patients with symptomatic coronary, carotid lesion, or both territories involvements. The choice of particular miRs was based on database research (Pub-Med, Bethesda, MD, USA) taking into consideration the relationship with development of atherosclerosis and potential prognostic value. Levels of circulating miRs (miR-1-3p, miR-16-5p, miR-34a-5p, mir-122-5p, miR-124-3p, miR-133a-3p, miR-133b, miR-134-5p, miR-208b-3p, miR-375 and miR-499-5p) were compared in 142 patients with an acute ischemic event resulting from carotid and/or coronary artery stenosis, who underwent revascularization for symptomatic lesion. A 6-year prospective evaluation of CVD/MI/IS risk was performed. Patients with two-territory as compared to single-territory involvement differed in levels of miR-1-3p (p = 0.016), miR-16-5p (p < 0.001), miR-34a-5p (p = 0.018), miR-122-5p (p = 0.007), miR-124-3p (p < 0.001) and miR-499-5p (p < 0.001). During follow-up, 62 (43.7%) episodes of CVD/MI/IS occurred. In multivariate Cox analysis, miR-122-5p (HR = 1.0006, 95%CI = 1.0001–1.0011) and peripheral artery disease (PAD) (HR = 2.16, 95%CI = 1.26–3.70) were associated with CVD/MI/IS risk; miR-1-3p (HR = 2.73, 95%CI = 1.22–6.12) and PAD (HR = 3.47, 95%CI = 1.88–6.41) with CVD; miR-122-5p (HR = 1.0001, 95%CI = 1.000–1.0002) and creatinine level (HR = 1.02, 95%CI = 1.01–1.04) with IS, and miR-16-5p (HR = 1.0004, 95%CI = 1.0001–1.0008) with MI. Expression of miR-1-3p, miR-16-5p and miR-122-5p during incident ischemia may be possible risk factors of secondary cardiovascular event(s).

Molecular mechanism of microRNA-26a regulation of phosphatase and tensin homolog gene in condyloma acuminatum and penile squamous cell carcinoma

OBJECTIVE

To investigate the expression levels and mechanisms of microRNA (miRNA) 26a (miR-26a) and phosphatase and tensin homolog (PTEN) in patients with human papillomavirus (HPV)-induced condyloma acuminatum (CA) and penile squamous cell carcinoma (PSCC).

METHODS

Thirty-one patients with HPV-positive CA and 28 with HPV-positive PSCC were included in this retrospective, cross-sectional study. PTEN mRNA and miR-26a levels in lesion tissues, blood, and urine were analyzed by quantitative reverse transcription polymerase chain reaction, and PTEN protein was detected by western blot and enzyme-linked immunosorbent assay. Cell proliferation was assessed by MTT assay. The interaction between miR-26a and PTEN was predicted by bioinformatics analysis and confirmed by dual luciferase reporter assay.

RESULTS

PTEN mRNA and protein levels were significantly lower and miR-26a levels were significantly higher in all samples from patients with PSCC compared with the CA group. Bioinformatics analysis and luciferase reporter assay confirmed PTEN as a target gene of miR-26a. Up-regulation of miR-26a significantly increased the proliferation of Penl1 PSCC cells.

CONCLUSIONS

PTEN expression is down-regulated and miR-26a levels are up-regulated in PSCC compared with CA. PTEN is a direct target gene of miR-26a. These results suggest that miR-26a might regulate HPV-positive progression from CA to PSCC through modulating PTEN.