miR-34a/Bcl-2 signaling pathway contributes to age-related hearing loss by modulating hair cell apoptosis

Knockdown of lncRNA BDNF-AS inhibited the progression of multiple myeloma by targeting the miR-125a/b-5p-BCL2 axis

Purpose

This study aimed to explore the role of long non-coding RNA (lncRNA) BDNF-AS in the progression of multiple myeloma (MM).

Methods

The expression of BDNF-AS, miR-125a-5p, and miR-125b-5p in MM serum and cell lines were detected by quantitative reverse transcriptase PCR (qRT-PCR). The binding relationships between miR-125a/b-5p and BDNF-AS or Bcl-2 were predicted by Starbase and verified by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) assay and 5-ethynyl-2′-deoxyuridine (EdU) staining assay. Cell migration was evaluated by wound healing assay. The expression levels of apoptosis-related proteins were evaluated by Western blot analysis. The role of BDNF-AS was also investigated in a xenograft tumor model in vivo.

Results

BDNF-AS was significantly upregulated, while miR-125a-5p and miR-125b-5p were downregulated in MM serum and corresponding cancer cell lines. Knockdown of BDNF-AS effectively inhibited the proliferation and migration of MM.1S and U266 cells, and co-transfection of miR-125a-5p or miR-125b-5p inhibitor and sh-BDNF-AS enhanced cell proliferation and migration compared with that in sh-BDNF-AS group. Knockdown of miR-125a-5p or miR-125b-5p significantly enhanced the proliferation and migration of MM.1S and U266 cells, and co-transfection of sh-Bcl-2 and miR-125a/b-5p inhibitor inhibited cell proliferation compared with that in miR-125a/b-5p inhibitor group. Moreover, knockdown of BDNF-AS increased the expression levels of apoptosis-related proteins (cleaved caspase 3 and cleaved PARP), while knockdown of miR-125a-5p or miR-125b-5p reduced the expression levels of these apoptosis-related proteins compared with knockdown of BDNF-AS. Furthermore, knockdown of BDNF-AS effectively suppressed MM tumor growth in vivo.

Conclusion

Our findings revealed that knockdown of BDNF-AS inhibited the progression of MM by targeting the miR-125a/b-5p-Bcl-2 axis, indicating that BDNF-AS might serve as a novel drug target for MM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12979-021-00258-5.

Tiliroside as a CAXII inhibitor suppresses liver cancer development and modulates E2Fs/Caspase-3 axis

Liver cancer is the fatal cause of cancer deaths worldwide due to its aggressiveness and lack of effective therapies. Tiliroside (C₃₀H₂₆O₁₃) is an active compound extracted from herb plant Tribulus terrestris L., which has been used as alternative therapy in clinic practice. However, its therapeutic use against liver cancer has not been previously reported. Here, we showed that Tiliroside exerted significantly higher anti-proliferation effect on liver cancer cell lines Hep3B and SNU-449 than on liver normal cell THLE-3 cells or NC group, respectively, by using MTS assay. Results from colony formation, immigration and invasion assays support the anticancer efficacy of Tiliroside and its low-toxic property while treating liver normal cell THLE-3. 3D spheroid formation and CD133 expression level also displays its anti-stemness effect. It has been showed that Tiliroside may function as Carbonic anhydrases XII (CAXII) inhibitor and affects apoptotic E2F1/E2F3/Caspase-3 axis by using CAXII esterase activity assay, Human carbonic anhydrase 12 (CA-12) ELISA Kit, quantitative reverse transcription PCR (RT-qPCR) as well as CaspACE Assay System, respectively. In summary, we demonstrate for the first time that Tiliroside suppresses liver cancer development possibly by acting as a novel CAXII inhibitor, which warrant further investigation on its therapeutic implications.

miR-424-5p reduces 5-fluorouracil resistance possibly by inhibiting Src/focal adhesion kinase signalling-mediated epithelial-mesenchymal transition in colon cancer cells

OBJECTIVES

miR-424-5p negatively regulates various malignant biological behaviours in tumour cells. We explored the relationship between miR-424-5p and 5-fluorouracil resistance in colon cancer cells.

METHODS

We developed 5-fluorouracil-resistant HT-29 cells and detected miR-424-5p expression using real-time fluorescence quantitative PCR. Cell viability was assessed using Cell Counting Kit-8 (CCK-8) assay. Immunofluorescence and western blotting were performed to determine protein levels. Apoptosis was detected by Annexin V-FITC/PI staining.

KEY FINDINGS

miR-424-5p was downregulated in 5-fluorouracil-resistant HT-29 cells. A miR-424-5p mimic enhanced the sensitivity of the resistant cells to 5-fluorouracil, whereas a miR-424-5p inhibitor promoted 5-fluorouracil resistance in HT-29 cells. Furthermore, the miR-424-5p mimic downregulated vimentin and upregulated E-cadherin in 5-fluorouracil-resistant HT-29 cells, whereas the miR-424-5p inhibitor exhibited opposite effects. The miR-424-5p inhibitor significantly inhibited 5-fluorouracil-induced HT-29 cell apoptosis and Src and focal adhesion kinase phosphorylation, whereas the miR-424-5p mimic showed opposite effects. Pretreatment with Src inhibitor 1 or focal adhesion kinase inhibitor 2 blocked the increase in Src and focal adhesion kinase phosphorylation and vimentin expression level and the decrease in E-cadherin expression level in miR-424-5p inhibitor-exposed HT-29 cells.

CONCLUSIONS

miR-424-5p suppressed epithelial-mesenchymal transition by inhibiting the Src/focal adhesion kinase signalling pathway to reduce 5-fluorouracil resistance in colon cancer cells.

RNA-seq analysis of potential lncRNAs for age-related hearing loss in a mouse model

Age-related hearing loss (AHL) is an important health problem in the elderly population. Its molecular mechanisms have not been fully elucidated. In this study, we analyzed the differential expression of lncRNAs and mRNAs in the cochleae of six-week-old and one-year-old C57BL/6J mice through RNA-seq analysis. We found 738 and 2033 differentially expressed lncRNAs and mRNAs, respectively, in these two groups (corrected P < 0.05). We focused on the intersection of known genes associated with hearing loss and differentially expressed mRNAs in RNA-seq. There are 34 mRNAs in this intersection, which include all 29 mRNAs enriched in the sensory perception of sound (GO: 0007605). We selected 11 lncRNAs that are predicted to regulate the 34 mRNAs to validate their expression levels in animal and cellular models of AHL by qRT-PCR. Among these lncRNAs, four were significantly different in both animal and cellular models of AHL, and the lncRNA NONMMUT010961.2 was the most markedly different. Knocking down lncRNA NONMMUT010961.2, we found the expression of oxidative stress and apoptosis-related gene Ar and hearing loss-related gene Hgf is significantly reduced in HEI-OC1 cells. Our results suggest that lncRNAs NONMMUT010961.2 may be associated with AHL and may thus lead to a new treatment for AHL.

Silencing of long‑chain non‑coding RNA GAS5 in osteoarthritic chondrocytes is mediated by targeting the miR‑34a/Bcl‑2 axis

The present study aimed to investigate the effects of the long non‑coding RNA (lncRNA) growth arrest‑specific transcript 5 (GAS5) on proliferation, apoptosis and the inflammatory response of osteoarthritic chondrocytes (OACs) and its associated mechanism of action. Primary chondrocytes were isolated from cartilage tissues of osteoarthritis (OA) patients for subculture. GAS5 was silenced in OACs by liposome transfection. The effects of GAS5 silencing on proliferation, apoptosis, stromal metabolism and inflammatory response of OACs were analyzed. The association of GAS5 with its target microRNA‑34a (miR‑34a) and the downstream target gene Bcl‑2 was verified by luciferase reporter assays. The results indicated that GAS5 silencing promoted the proliferation, inhibited cell apoptosis and caused G1 arrest of OACs compared with the control group (P<0.05). The expression levels of TNF‑α and IL‑6 in the supernatant of OACs in the si‑GAS5 group were significantly lower than those of the control group (P<0.05). The results of the double luciferase reporter assays indicated that overexpression of GAS5 downregulated miR‑34a and upregulated Bcl‑2 levels (P<0.05) compared with the expression levels of these markers in the control group. In contrast to GAS5 overexpression, knockdown of this RNA caused a significant upregulation of miR‑34a levels and a significant downregulation in the levels of Bcl‑2 (P<0.05). Moreover, GAS5 overexpression could counteract the inhibition of apoptosis by overexpression of miR‑34a (P<0.05). The data indicated that GAS5 participated in the development of OA by regulating the biological behavior of chondrocytes via the miR‑34a/Bcl‑2 axis.

Long noncoding RNA CPS1-IT1 suppresses melanoma cell metastasis through inhibiting Cyr61 via competitively binding to BRG1

Long noncoding RNA CPS1-IT1 is recently recognized as a tumor suppressor in several cancers. Here, we investigate the role of CPS1-IT1 in human melanoma. Presently, our study reveals the low expression of CPS1-IT1 in human melanoma tissues and cell lines, which is significantly associated with metastasis and tumor stage. Besides, the potential of CPS1-IT1 as a prognosis-predictor is strongly indicated. Functionally, CPS1-IT1 overexpression inhibits cell migration, invasion, epithelial-mesenchymal transition, and angiogenesis in melanoma cells. CYR61, an angiogenic factor that participates in tumor metastasis as well as a recognized oncogene in melanoma, is shown to be confined under CPS1-IT1 overexpression in melanoma cells. Furthermore, enforced expression of Cyr61 in CPS1-IT1-silenced melanoma cells dramatically normalized the protein level of Cyr61 and that of its downstream targets vascular endothelial growth factor and matrix metalloproteinase-9, as well as the repressive effect of CPS1-IT1 overexpression on melanoma cell metastasis. BRG1, a core component of SWI/SNF complex, is implied to interact with both CPS1-IT1 and Cyr61 in melanoma cells. Moreover, CPS1-IT1 negatively regulates Cyr61 expression by blocking the binding of BRG1 to Cyr61 promoter. Jointly, CPS1-IT1 controls melanoma metastasis through impairing Cyr61 expression via competitively binding with BRG1, uncovering a novel potential therapeutic and prognostic biomarker for patients with melanoma.

MicroRNA-204 may participate in the pathogenesis of hypoxic-ischemic encephalopathy through targeting KLLN

Hypoxic-ischemic encephalopathy (HIE) is a common neonatal disease that can lead to high neonatal mortality rates. Previous studies have indicated that microRNAs (miRs) may be involved in the pathogenesis of HIE; however, the specific mechanisms underlying their involvement require further investigation. The aim of the present study was to investigate the roles of miR-204 and its target gene killin p53 regulated DNA replication inhibitor (KLLN) in HIE using rat HIE models. Brain injury was induced by surgery and incubation of hypoxic incubator brain using 10-day-old pup rats. On day 3, rats were sacrificed, and the infarct size of the brain was determined using a tetrazolium chloride assay. Terminal deoxynucleotidyl transferase UTP nick-end labeling staining was performed to detect the cell death rate in the brain tissue. Following this, the brain tissues were collected, and reverse transcription-quantitative polymerase chain reaction, western blot analysis and immunohistochemistry assays were performed to examine the expression levels of miR-204 and KLLN. Furthermore, neurons were cultured and transfected with miR-204 inhibitors or mimics, and the effect of miR-204 on the proliferation and apoptosis of neurons was examined using MTT and flow cytometric assays. Finally, a dual-luciferase reporter assay was performed to confirm whether KLLN is a direct target of miR-204. The expression of miR-204 was significantly downregulated and the expression of KLLN was significantly increased in the brain tissue of HIE rats (P<0.001). In addition, the transfection with miR-204 inhibitors significantly decreased the proliferation rates and significantly increased the apoptosis rate of neurons; however, transfection with miR-204 mimics prompted the opposite results. The dual-luciferase reporter assay also confirmed that KLLN is a direct target of miR-204. Taken together, the results of the present study demonstrated that miR-204 was downregulated in HIE and that miR-204 may serve important roles in the pathogenesis of HIE through targeting KLLN.

miR-15a: a potential diagnostic biomarker and a candidate for non-operative therapeutic modality for age-related cataract

Introduction: In order to better understand the role of hsa-miR-15a in the pathogenesis of age-related cataracts, we hypothesised altered expression, and of target anti-apoptotic genes, BCL-2 and MCL-1, in lens epithelial cells amongst age-related cataract patients.Material and methods: Reverse transcription quantitative polymerase chain reaction (RT-qPCR) quantified the expression of hsa-miR-15a and the target genes BCL-2 and MCL-1 in lens epithelial cells of 120 age-related cataract patients (40 patients with cortical cataracts, 40 patients with nuclear cataracts and 40 patients with posterior subcapsular cataracts) and 40 controls. Sixty specimens (15 normal and 45 cataracts) were stained immunohistochemically with BCL-2 and MCL-1 markers.Results: The expression of hsa-miR-15a was significantly increased (p = 0.003) in lens epithelial cells of cataract patients compared to the control group. BCL-2 and MCL-1 expression levels were significantly decreased in cataract patients (p < 0.001). A significant increase in hsa-miR-15a expression in the cortical subtype compared to the posterior subcapsular subtype (p = 0.003) and a significant decrease in BCL-2 and MCL-1 expressions in the cortical subtype compared to the nuclear and the posterior subcapsular subtype was detected.Conclusions: The increased expression of hsa-miR-15a in lens epithelial cells of cataract patients may repress the expression of BCL-2 and MCL-1. The expression of hsa-miR-15a and the subsequent apoptosis of lens epithelial cells are part of the pathogenesis of age-related cataracts.

MicroRNAs in acquired sensorineural hearing loss

OBJECTIVE

This review summarises the current literature on the role of microRNAs in presbyacusis (age-related hearing loss) and sudden sensorineural hearing loss.

METHODS

Medline, PubMed, Web of Science and Embase databases were searched for primary English-language studies, published between 2000 and 2017, which investigated the role of microRNAs in the pathogenesis of presbyacusis or sudden sensorineural hearing loss. Quality of evidence was assessed using the National Institutes of Health quality assessment tool.

RESULTS

Nine of 207 identified articles, 6 of good quality, satisfied the review's inclusion criteria. In presbyacusis, microRNAs in pro-apoptotic and autophagy pathways are upregulated, while microRNAs in proliferative and differentiation pathways are downregulated. Evidence for microRNAs having an aetiological role in sudden hearing loss is limited.

CONCLUSION

A shift in microRNA expression, leading to reduced cellular activity and impaired inner-ear homeostasis, may contribute to the pathogenesis of presbyacusis.

Cmah deficiency may lead to age-related hearing loss by influencing miRNA-PPAR mediated signaling pathway

Background

Previous evidence has indicated CMP-Neu5Ac hydroxylase (Cmah) disruption inducesaging-related hearing loss (AHL). However, its function mechanisms remain unclear. This study was to explore the mechanisms of AHL by using microarray analysis in the Cmah deficiency animal model.

Methods

Microarray dataset GSE70659 was available from the Gene Expression Omnibus database, including cochlear tissues from wild-type and Cmah-null C57BL/6J mice with old age (12 months, n = 3). Differentially expressed genes (DEGs) were identified using the Linear Models for Microarray data method and a protein–protein interaction (PPI) network was constructed using data from the Search Tool for the Retrieval of Interacting Genes database followed by module analysis. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis was performed using the Database for Annotation, Visualization and Integrated Discovery. The upstream miRNAs and potential small-molecule drugs were predicted by miRwalk2.0 and Connectivity Map, respectively.

Results

A total of 799 DEGs (449 upregulated and 350 downregulated) were identified. Upregulated DEGs were involved in Cell adhesion molecules (ICAM1, intercellular adhesion molecule 1) and tumor necrosis factor (TNF) signaling pathway (FOS, FBJ osteosarcoma oncogene; ICAM1), while downregulated DEGs participated in PPAR signaling pathway (PPARG, peroxisome proliferator-activated receptor gamma). A PPI network was constructed, in which FOS, ICAM1 and PPARG were ranked as hub genes and PPARG was a transcription factor to regulate other target genes (ICAM1, FOS). Function analysis of two significant modules further demonstrated PPAR signaling pathway was especially important. Furthermore, mmu-miR-130b-3p, mmu-miR-27a-3p, mmu-miR-27b-3p and mmu-miR-721 were predicted to regulate PPARG. Topiramate were speculated to be a potential small-molecule drug to reverse DEGs in AHL.

Conclusions

PPAR mediated signaling pathway may be an important mechanism for AHL. Downregulation of the above miRNAs and use of topiramate may be potential treatment strategies for ALH by upregulating PPARG.

MicroRNA-34a suppresses aggressiveness of hepatocellular carcinoma by modulating E2F1, E2F3, and Caspase-3

Background: Accumulating evidence suggests an antineoplastic role of MicroRNA-34a (miR-34a) in human cancer. However, its precise biological functions stay largely elusive. Purpose: Our study was aimed to investigate the impact of miR-34a on hepatocellular carcinoma (HCC) and its underlying apoptosis related mechanisms in vitro, as well as the association of miR-34a, E2F1 and E2F3 expression with patient survival of HCC using publicly accessed datasets. Methods: The HBV-expressing Hep3B and SNU-449 cell lines with or without enforced expression of miR-34a were in vitro cultured for cell proliferation, colony formation, wound healing, cell invasion, and 3D spheroid formation. Quantitative reverse transcription PCR (RT-qPCR) was performed for E2F1, E2F3 expression. Caspase-3 (CASP3) activity was determined using a CaspACE^TM Assay System. Kaplan-Meier survival curves were used to analyze the associations of miR-34a, E2F1 and E2F3 expression and overall survival in HCC. Meta-analysis was performed to examine the differential expression of E2F1 and E2F3 between primary HCC vs normal tissues. Results: The results in vitro showed that enforced miR-34a expression significantly inhibited cell proliferation, migration, and invasion of both Hep3B and SNU-449. RT-qPCR results demonstrated that miR-34a could significantly suppress E2F1 and E2F3 expression, particularly in SNU-449. CASP3 activity in both Hep3B and SNU-449 increased in miR-34a treatment group. Overexpressed E2F1 and E2F3 were observed in primary HCC vs normal tissues. Survival analyses showed that HCC patients with either high miR-34a, or low E2F1, or low E2F3 expression had better survival than their opposite counterparts, respectively. Conclusion: Our study suggested thatmiR-34a can modulate the expression of E2F1, E2F3, and CASP3 activity, thereby repressing tumor aggressiveness and expediting apoptosis in liver cancer cells.

Maternal folic acid deficiency stimulates neural cell apoptosis via miR-34a associated with Bcl-2 in the rat foetal brain

Embryonic development is a critical period wherein brain neurons are generated and organized. Maternal dietary folate, a cofactor in one-carbon metabolism, modulates neurogenesis and apoptosis in foetal brain neurons. We hypothesized that aberrant neuronal apoptosis may affect the development of the central nervous system during maternal folic acid deficiency, with evident effects because maternal folic acid deficiency modulates the microRNA-34a associated with Bcl-2 pathway during embryonic development. Four-week-old female Sprague-Dawley rats were divided randomly into two groups (10 rats per group): a folate-deficient diet group and a folate-normal diet group. The diets were administered to the rats 60 d before mating, which was continued for the pregnant dams until parturition. Maternal folic acid deficiency increased neuronal apoptosis in the hippocampus and the cortex in the offspring. Furthermore, maternal folic acid deficiency increased the ratio of cleaved caspase-3/caspase-3, followed by an increase in caspase-3 activity. Moreover, maternal folic acid deficiency downregulated Bcl-2 and upregulated Bax, and this effect associate with maternal folic acid deficient increases expression of microRNA-34a. Together, the present results indicate that maternal folic acid deficiency stimulates neuronal apoptosis via microRNA-34a associated with Bcl-2 signalling in rat offspring.

miR-34a/BCL-2 signaling axis contributes to apoptosis in MPP+ -induced SH-SY5Y cells

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disorder which mainly affects the elderly population of various societies. The main hallmark of this disease is the loss of dopaminergic (DA) neurons. So far, numerous studies have implied the role of microRNAs in fine-tuning cellular processes including apoptosis. Studies have also shown that miR-34a is mainly involved in age-related disorders including Alzheimer's disease, and its expression is usually higher in the brain sample patients. Furthermore, the key role of miR-34a in the expression of BCL-2, and thus, in vitro and in vivo apoptosis has been revealed. miR-34a/BCL-2 axis is therefore of critical importance in inducing or inhibiting apoptosis.

METHODS

In this study, human SH-SY5Y cells were treated with MPP+ and the expression of miR-34a and BCL2 was assessed.

RESULTS

Our results also showed that treating human SH-SY5Y neuronal cells using MPP+ to induce oxidative stress and apoptosis led to the upregulation of miR-34a, as compared to the nontreated control group. Moreover, evaluating the expression level of BCL-2 in these cells indicated a contradictory pattern, as compared with miR-34a. It was also revealed that the expression of BCL-2 was significantly decreased in MPP+ -treated cells, thereby confirming previous studies regarding a new concept. In this study, we show that miR-34a/BCL-2 axis is directly correlated with oxidative stress and apoptosis in SH-SY5Y cells as a model of DA neurons.

CONCLUSION

miR-34a and its target gene, BCL-2, play a possible role in the induction of apoptosis in DA neurons, and therefore, they have a potential role in the pathogenesis of PD. Consequently, the therapeutic potential of miR-34a could be considered in order to inhibit the progression of PD.

Intracellular Regulome Variability Along the Organ of Corti: Evidence, Approaches, Challenges, and Perspective

The mammalian hearing organ is a regular array of two types of hair cells (HCs) surrounded by six types of supporting cells. Along the tonotopic axis, this conserved radial array of cell types shows longitudinal variations to enhance the tuning properties of basilar membrane. We present the current evidence supporting the hypothesis that quantitative local variations in gene expression profiles are responsible for local cell responses to global gene manipulations. With the advent of next generation sequencing and the unprecedented array of technologies offering high throughput analyses at the single cell level, transcriptomics will become a common tool to enhance our understanding of the inner ear. We provide an overview of the approaches and landmark studies undertaken to date to analyze single cell variations in the organ of Corti and discuss the current limitations. We next provide an overview of the complexity of known regulatory mechanisms in the inner ear. These mechanisms are tightly regulated temporally and spatially at the transcription, RNA-splicing, mRNA-regulation, and translation levels. Understanding the intricacies of regulatory mechanisms at play in the inner ear will require the use of complementary approaches, and most probably, a combinatorial strategy coupling transcriptomics, proteomics, and epigenomics technologies. We highlight how these data, in conjunction with recent insights into molecular cell transformation, can advance attempts to restore lost hair cells.