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Background: Depressive disorder is a common and serious public health challenge globally. Fructus arctii is a traditional medicinal plant ingredient with diverse pharmacological effects. This study aimed to investigate the therapeutic potential of Fructus arctii in alleviating depressive‐like behaviors. Materials and Methods: We established a chronic unpredictable mild stress (CUMS)‐induced depression mouse model to assess the antidepressant effects of Fructus arctii. BV2 cells treated with lipopolysaccharide (LPS) were used to mimic neuronal damage. Behavioral tests, including the sucrose preference test, tail‐suspension test, and forced swim test, were conducted to evaluate the impact of Fructus arctii on depressive‐like behaviors. Let‐7e expression was detected by RT‐qPCR, and TLR4 signaling pathway activation was evaluated by western blot analysis, which also assessed the inflammatory response by measuring levels of IL‐6, IL‐1β, MCP‐1, TNF‐α, and iNOS. Immunohistological analysis was conducted to detect the expression of microglia markers. Luciferase reporter assays verified the interaction between let‐7e and TLR4. Results: Fructus arctii administration effectively alleviated depressive‐like behaviors induced by CUMS in mice, as evidenced by improved sucrose preference and reduced immobility time in behavioral tests. Mechanistically, Fructus arctii reversed the CUMS‐induced downregulation of let‐7e and upregulation of TLR4 and MyD88 protein levels in mice hippocampus tissues. In addition, Fructus arctii suppressed microglial activation and reduced the levels of inflammatory factors by upregulating let‐7e. Let‐7e was verified to bind to TLR4, thereby negatively regulating its expression. TLR4 overexpression reversed the suppressive effect of let‐7e upregulation on inflammatory reactions and microglial activation. Furthermore, intracerebroventricular injection of let‐7e agomiR alleviated depressive‐like behavior and inhibited microglial activation in vivo. Conclusion: In summary, Fructus arctii mitigates depression by regulating the let‐7e/TLR4/MyD88 pathway, offering new insights into potential depression therapies. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Depressive disorder is a common and serious public health challenge globally. Fructus arctii is a traditional medicinal plant ingredient with diverse pharmacological effects. This study aimed to investigate the therapeutic potential of Fructus arctii in alleviating depressive‐like behaviors. Materials and Methods We established a chronic unpredictable mild stress (CUMS)‐induced depression mouse model to assess the antidepressant effects of Fructus arctii. BV2 cells treated with lipopolysaccharide (LPS) were used to mimic neuronal damage. Behavioral tests, including the sucrose preference test, tail‐suspension test, and forced swim test, were conducted to evaluate the impact of Fructus arctii on depressive‐like behaviors. Let‐7e expression was detected by RT‐qPCR, and TLR4 signaling pathway activation was evaluated by western blot analysis, which also assessed the inflammatory response by measuring levels of IL‐6, IL‐1β, MCP‐1, TNF‐α, and iNOS. Immunohistological analysis was conducted to detect the expression of microglia markers. Luciferase reporter assays verified the interaction between let‐7e and TLR4. Results Fructus arctii administration effectively alleviated depressive‐like behaviors induced by CUMS in mice, as evidenced by improved sucrose preference and reduced immobility time in behavioral tests. Mechanistically, Fructus arctii reversed the CUMS‐induced downregulation of let‐7e and upregulation of TLR4 and MyD88 protein levels in mice hippocampus tissues. In addition, Fructus arctii suppressed microglial activation and reduced the levels of inflammatory factors by upregulating let‐7e. Let‐7e was verified to bind to TLR4, thereby negatively regulating its expression. TLR4 overexpression reversed the suppressive effect of let‐7e upregulation on inflammatory reactions and microglial activation. Furthermore, intracerebroventricular injection of let‐7e agomiR alleviated depressive‐like behavior and inhibited microglial activation in vivo. Conclusion In summary, Fructus arctii mitigates depression by regulating the let‐7e/TLR4/MyD88 pathway, offering new insights into potential depression therapies.

Glioblastoma (GBM) is a highly invasive neurological malignancy with poor prognosis. LncRNA-GAS5 (growth arrest-specific transcript 5) is a tumor suppressor involved in multiple cancers. In this study, we explored the clinical significance, biological function, and underlying mechanisms of GAS5 in GBM. We showed that lncRNA-GAS5 expression decreased in high-grade glioma tissues and cells, which might be associated with poor prognosis. GAS5 overexpression lowered cell viability, suppressed GBM cell migration and invasion, and impaired the stemness and proliferation of glioma stem cells (GSCs). We further discovered that GAS5 inhibited the viability of glioma cells through miR-let-7e and miR-125a by protecting SPACA6 from degradation. Moreover, GAS5 played an anti-oncogenic role in GBM through the combined involvement of let-7e and miR-125a in vivo and in vitro. Notably, these two miRNAs block the IL-6/STAT3 pathway in tumor tissues extracted from a xenograft model. Taken together, our study provides evidence for an important role of GAS5 in GBM by affecting the proliferation and migration of GSCs, thus providing a new potential prognostic biomarker and treatment strategy for GBM. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNA) are major regulators of intercellular communication and key players in the pathophysiology of cardiovascular disease. This study aimed to determine the miRNA fingerprint in a cohort of 53 patients with acute myocardial infarction (AMI) with non-ST-segment elevation (NSTEMI) relative to miRNA expression in healthy controls (n = 51). miRNA expression was initially profiled by miRNA array in the serum of patients undergoing cardiac catheterization during NSTEMI (n = 8) and 1 year past the event (follow-up, n = 8) and validated in the entire cohort. In total, 58 miRNAs were differentially expressed during AMI (p < 0.05), while 36 were modified at follow-up (Fisher's exact test: p = 0.0138). Enrichment analyses revealed differential regulation of biological processes by miRNA at each specific time point (AMI vs. follow-up). During AMI, the miRNA profile was associated mainly with processes involved in vascular development. However, 1 year after AMI, changes in miRNA expression were partially related to the regulation of cardiac tissue morphogenesis. Linear correlation analysis of miRNA with serum levels of cytokines and chemokines revealed that let-7g-5p, let-7e-5p, and miR-26a-5p expression was inversely associated with serum levels of pro-inflammatory cytokines TNF-α, and the chemokines MCP-3 and MDC. Transient transfection of human endothelial cells (HUVEC) with let-7e-5p inhibitor or mimic demonstrated a key role for this miRNA in endothelial function regulation in terms of cell adhesion and angiogenesis capacity. HUVEC transfected with let-7e-5p mimic showed a 20% increase in adhesion capacity, whereas transfection with let-7e-5p inhibitor increased the number of tube-like structures. This study pinpoints circulating miRNA expression fingerprint in NSTEMI patients, specific to the acute event and changes at 1-year follow-up. Additionally, given its involvement in modulating endothelial cell function and vascularization, altered let-7e-5p expression may constitute a therapeutic biomarker and target for ischemic heart disease. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is one of the most severe neurodegenerative diseases observed in the elderly population. Although the hallmarks of AD have been identified, the methods for its definitive diagnosis and treatment are still lacking. Extracellular vesicles (EVs) have become a promising source for biomarkers since the identification of their content. EVs are released from multiple cell types and, when released from neurons, they pass from the brain to the blood with their cargo molecules. Hence, neuron-specific EV-resident microRNAs (miRNAs) are promising biomarkers for diagnosis of AD. This study aimed to identify altered miRNA content in small neuron-derived extracellular vesicles (sNDEVs) isolated from AD patients and healthy individuals. Furthermore, we examined the role of sNDEV-resident miRNAs in neuron-glia cellular interaction to understand their role in AD propagation. We identified 10 differentially expressed miRNAs in the sNDEVs of patients via next-generation sequencing and validated the most dysregulated miRNA, let-7e, with qRT-PCR. Let-7e was significantly increased in the sNDEVs of AD patients compared with those of healthy controls in a larger cohort. First, we evaluated the diagnostic utility of let-7e via ROC curve analysis, which revealed an AUC value of 0.9214. We found that IL-6 gene expression was increased in human microglia after treatment with sNDEVs of AD patients with a high amount of let-7e. Our study suggests that sNDEV-resident let-7e is a potential biomarker for AD diagnosis, and that AD patient-derived sNDEVs induce a neuroinflammatory response in microglia. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNA) are major regulators of intercellular communication and key players in the pathophysiology of cardiovascular disease. This study aimed to determine the miRNA fingerprint in a cohort of 53 patients with acute myocardial infarction (AMI) with non-ST-segment elevation (NSTEMI) relative to miRNA expression in healthy controls (n = 51). miRNA expression was initially profiled by miRNA array in the serum of patients undergoing cardiac catheterization during NSTEMI (n = 8) and 1 year past the event (follow-up, n = 8) and validated in the entire cohort. In total, 58 miRNAs were differentially expressed during AMI (p < 0.05), while 36 were modified at follow-up (Fisher’s exact test: p = 0.0138). Enrichment analyses revealed differential regulation of biological processes by miRNA at each specific time point (AMI vs. follow-up). During AMI, the miRNA profile was associated mainly with processes involved in vascular development. However, 1 year after AMI, changes in miRNA expression were partially related to the regulation of cardiac tissue morphogenesis. Linear correlation analysis of miRNA with serum levels of cytokines and chemokines revealed that let-7g-5p, let-7e-5p, and miR-26a-5p expression was inversely associated with serum levels of pro-inflammatory cytokines TNF-α, and the chemokines MCP-3 and MDC. Transient transfection of human endothelial cells (HUVEC) with let-7e-5p inhibitor or mimic demonstrated a key role for this miRNA in endothelial function regulation in terms of cell adhesion and angiogenesis capacity. HUVEC transfected with let-7e-5p mimic showed a 20% increase in adhesion capacity, whereas transfection with let-7e-5p inhibitor increased the number of tube-like structures. This study pinpoints circulating miRNA expression fingerprint in NSTEMI patients, specific to the acute event and changes at 1-year follow-up. Additionally, given its involvement in modulating endothelial cell function and vascularization, altered let-7e-5p expression may constitute a therapeutic biomarker and target for ischemic heart disease.

Abstract Background Resistance to platinum-based chemotherapy remains a great challenge for ovarian cancer treatment. The human let-7 family contains 13 members located on nine different chromosomes, and most members have been implicated in the modulation of drug sensitivity in cancers. Our previous study showed that deregulation of let-7e in epithelial ovarian cancer (EOC) promoted the development of resistance to cisplatin. In the present study, we aimed to investigate the underlying mechanism and further evaluate the clinical value of let-7e in predicting chemo-response and prognosis in EOC. Results In situ hybridization assays revealed a significantly decreased expression of let-7e in chemo-resistant EOC tissues compared with chemo-sensitive cases. Transfection with let-7e agomir sensitized EOC cells to cisplatin, down-regulated BRCA1 and Rad51 expression, and repressed the repair of cisplatin-induced DNA double strand break, while let-7e inhibitor exerted the opposite effects. In human EOC tissues, BRCA1 and Rad51 levels were increased in the chemo-resistant group compared with the sensitive group and were negatively correlated with let-7e. Low let-7e and high Rad51 were significantly associated with poor progression-free survival and overall survival and multivariate regression analyses showed that let-7e was an independent predictor for overall survival and chemotherapy response in EOC. Receiver operating characteristic analysis indicated that let-7e level was highly predictive of resistance to platinum-taxane chemotherapy with an area under the curve of 0.826. Conclusions In EOC, low let-7e leads to activation of BRCA1 and Rad51 expression and subsequent enhancement of DSB repair, which in turn results in cisplatin-resistance. Let-7e is a potential predictor for survival and chemo-response in EOC and re-expression of let-7e might be an effective strategy for overcoming chemo-resistance.

Abnormal expression of various microRNAs (miRNAs), as regulators of biological signaling pathways, has a strong association with cancer resistance to chemotherapy and radiotherapy. The let‐7 family of miRNAs as tumor suppressors have shown to be downregulated in different types of human malignancies including colorectal cancer (CRC). However, the biological function of let‐7 members in the processes of resistance to radiation in CRC has not yet been completely elucidated. Insulin‐like growth factor 1 receptor (IGF‐1R) signaling pathway is amplified in CRC and leads to its progression, development, and also radiation resistance. So, it seems like an attractive target for anticancer therapy. In this study, by using bioinformatics analysis, it has been revealed that IGF‐1R is a direct target of the let‐7e member. Consistent with this, we identified that increased levels of let‐7e in CRC cells reduced IGF‐1R protein level and subsequently its downstream signaling pathways, which resulted in the G1 cell cycle arrest and a significant reduction in the proliferation, survival and also resistance to radiation of CRC cells. Altogether, these results suggested that let‐7e by targeting the IGF‐1R signaling pathway might serve as therapeutics in anticancer therapy. The let‐7 family of microRNAs (miRNAs) as tumor suppressors have shown to be downregulated in different types of human malignancies including colorectal cancer (CRC). However, the biological function of let‐7 members in the processes of resistance to radiation in CRC have not yet been completely elucidated. So, it seems as an attractive target for anticancer therapy. The aim of this study is to investigate the role of let‐7e‐5p in radiosensitivity of CRC through targeting insulin‐like growth factor 1 receptor (IGF‐1R) as a candidate of radiation resistance. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are small noncoding RNAs that negatively control gene expression at the translational level. There are compelling evidences indicating that the expression of let-7e is downregulated in various cancers, however, the role of let-7e in colorectal cancer (CRC) and its mechanism has been remained unknown. Here, we investigated the potential role of let-7e in regulating CRC cells phenotypes. Let-7e and DCLK1 siRNA were transfected in HCT-116 cells. Colony formation assay, scratch test, Annexin V/PI flow cytometry, and sphere formation assay were performed to examine the cell proliferation, migration, apoptosis, and stemness, respectively. The expression of let-7e, epithelial-mesenchymal transition (EMT)-related genes, Doublecortin like kinase protein 1 (DCLK1), and cancer stem cells (CSCs) were assessed using RT-qPCR while the protein level of DCLK1 was determined by western blotting. Overexpression of let-7e effectively inhibited cell proliferation, suppressed migration, reduced sphere formation, and precluded EMT process as well as stemness factors. Furthermore, let-7e suppressed DCLK1 expression. Additionally, we found that the expression of let-7e was negatively correlated with DCLK1 expression in CRC cells. Let-7e plays an important role as tumor suppressor miRNA in CRC probably through inhibition of DCLK1 expression. [ABSTRACT FROM AUTHOR]

Myeloid‐derived suppressor cells (MDSCs) represent a group of immature myeloid cells composed of myeloid progenitor cells and immature myeloid cells that can negatively regulate immune responses by inhibiting T‐cell function. In mice, MDSCs are broadly defined by the expression of CD11b and Gr1. We and others have shown that injection of a lethal or sublethal dose of lipopolysaccharide (LPS) into mice could result in the expansion of MDSCs in the bone marrow (BM), spleen and blood. Until now, the molecular mechanisms responsible for this expansion are poorly studied; specifically, the roles of the individual microRNAs (miRNAs) which may be involved remain largely unknown. We performed microarray analysis to compare the miRNA expression profiles of CD11b+Gr1+ cells sorted from the BM of LPS‐injected and phosphate‐buffered saline‐injected mice. We identified let‐7e, which was highly upregulated in the LPS‐treated group, as a potent regulator of LPS‐induced MDSC expansion. Furthermore, let‐7e overexpression in BM chimeric mice led to a noticeable increase in the population of CD11b+Gr1+ cells, which resulted from reduced cellular apoptosis. Further studies showed that let‐7e could directly target caspase‐3 to inhibit cell apoptosis, and upregulation of let‐7e in LPS‐stimulated MDSCs could be due to the relieved repression of let‐7e transcription exerted by downregulated GATA2. Our findings suggest that LPS expands MDSCs by inhibiting apoptosis through the regulation of the GATA2/let‐7e axis. In myeloid‐derived suppressor cells (MDSCs), GATA2 is a transcription repressor for let‐7e. Lipopolysaccharide stimulation can downregulate GATA2 and thus upregulate let‐7e, which can target caspase‐3 to inhibit cell apoptosis, and promotes MDSC accumulation. [ABSTRACT FROM AUTHOR]

Tumor necrosis factor α (TNFα), an important inflammatory cytokine, is associated with dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), a severe pathological manifestation of dengue virus (DENV) infection. However, the regulatory mechanism of microRNA on TNFα is currently unknown. Our study showed that the TNFα expression increased immediately and then later decreased, while a marked increase for the miRNA let‐7e was detected in dengue virus type 2 (DENV2)‐infected peripheral blood mononuclear cells (PBMCs). From this study, we found that let‐7e was able to inhibit TNFα expression, but bioinformatics analysis showed that the enhancer of zeste homolog 2 (EZH2) was the potential direct target of let‐7e instead of TNFα. EZH2 methyl transferase can produce H3K27me3 and has a negative regulatory role. Using a dual‐luciferase reporter assay and Western blotting, we confirmed that EZH2 was a direct target of let‐7e and found that siEZH2 could inhibit TNFα expression. In the further study of the regulatory mechanism of EZH2 on TNFα expression, we showed that siEZH2 promoted EZH1 and H3K4me3 expression and inhibited H3K27me3 expression. More importantly, we revealed that siEZH2 down‐regulated NF‐κB p65 within the nucleus. These findings indicate that the let‐7e/EZH2/H3K27me3/NF‐κB p65 pathway is a novel regulatory axis of TNFα expression. In addition, we determined the protein differences between siEZH2 and siEZH2‐NC by iTRAQ and found a number of proteins that might be associated with TNFα. [ABSTRACT FROM AUTHOR]

Chronic inflammation and abnormalities in Toll-like receptor (TLR) signaling pathways are associated with major depressive disorder (MDD). Our previous work reported that impaired negative regulators for the TLR pathways are associated with MDD. This study aimed to assess the association between the severity of depression and the intracellular microRNAs that regulate TLR4 signaling in both peripheral blood mononuclear cells (PBMCs) and monocytes from MDD patients. The severity of MDD before and after antidepressant treatment was determined by the 17-item Hamilton Depression Rating Scale, and quantitative RT-PCR was used to measure the levels of intracellular regulatory microRNAs, including let-7e, miR-21-5p miR-145, miR-223, miR-146a, and miR-155, in PBMCs and monocytes isolated from 43 healthy controls and 84 patients with MDD before and after treatment with antidepressants. Assays of PBMCs showed that the levels of let-7e, miR-146a, and miR-155 were lower in MDD patients than in healthy controls and were significantly higher after than before treatment in the 69 patients who completed treatment with antidepressants for four weeks. Levels of miR-146a and miR-155 in monocytes were lower in MDD patients than in controls and were increased in the former after antidepressant treatment. Multiple linear regression analyses found that let-7e and miR-146a expression before treatment was inversely correlated with severity of depression, whereas miR-155 before treatment was directly correlated with severity of depression. These findings suggest that intracellular regulatory microRNAs which regulate TLR4 signaling are aberrantly expressed in patients with MDD and that these levels are ameliorated by antidepressant treatment.

Colorectal cancer (CRC) is one of the leading causes of cancer mortality worldwide. Aberrant sialylation is crucially involved in the progression of various types of cancer. MicroRNAs (miRNAs) have been broadly studied in cancer. MicroRNA-33a (miR-33a) and Has-let-7e (let-7e) are non-coding RNA that can reduce cell motility and viability in cancer. In this study, miR-33a and let-7e levels were confirmed to be significantly down-regulated in CRC samples (n = 32) and drug resistant cell line (HCT-8/5-FU) compared with those in the matched adjacent tissues and drug sensitivity cell line (HCT-8). ST8SIA1 was highly expressed in CRC tissues and HCT-8/5-FU cells, which was negatively correlated with miR-33a/let-7e expression. Luciferase reporter assays confirmed that both miR-33a and let-7e bound to the 3'-untranslated (3'-UTR) region of ST8SIA1. Inhibiting miR-33a/let-7e expression in CRC cells increased endogenous ST8SIA1 mRNA and protein levels. MiR-33a/let-7e knockdown promoted chemoresistance, proliferation, invasion, angiogenesis in vitro, and tumor growth in vivo. Whereas, ectopic expression of miR-33a/let-7e suppressed chemoresistance, proliferation, invasion and angiogenesis in CRC cell lines. ST8SIA1 knockdown mimicked the tumor suppressive effect of miR-33a/let-7e on CRC cells, while restoration of ST8SIA1 abolished the tumor suppressive effect of miR-33a/let-7e on CRC cells. Taken together, altered expression of miR-33a/let-7e was correlated with ST8SIA1 level, which might contribute to CRC progression. The miR-33a/let-7e-ST8SIA1 axis could be a therapeutic target for CRC patients. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine the expression levels and clinical significance of circulating microRNAs (miRNAs), let-7e and miR-338 at different stages following ischemic stroke (IS). Seventy-two patients with IS at the acute stage were enrolled and monitored at different stages, and 51 healthy volunteers were served as the normal controls. Expression of let-7e and miR-338 in serum and cerebral spinal fluid (CSF) samples was analyzed by real-time quantitative PCR. The relationship between expression levels of let-7e and miR-338, National Institutes of Health Stroke Scale (NIHSS) scores, and the levels of serum CRP was analyzed, respectively. Compared to healthy controls, serum let-7e expression levels were significantly increased, while serum miR-338 expression levels were slightly increased in IS patients. Expression levels of Let-7e in serum varied at different stages in IS patients with the lowest expression in the recover stage and highest expression in the acute stage. However, serum miR-338 expression in IS patients was not significantly different in any stage. Compared to healthy controls and nonacute stages of IS groups, let-7e expression in CSF was markedly upregulated in IS patients at the acute stage. Different from that of let-7e, miR-338 expression in CSF was upregulated in IS patients only at the subacute stage but not in the acute stage. Meanwhile, let-7e, which was not significantly correlated with NIHSS scores ( r = 0.29, P > 0.05), was positively correlated with the serum CRP levels ( r = 0.67, P = 0.033). There is no significant correlation between the miR-338 expression levels and NIHSS scores or serum CRP levels. Moreover, let-7e, but not miR-338, had a high consistency in expression when tested both in CSF and serum samples. Finally, serum let-7e showed a specificity up to 73.4 % and a sensitivity of 82.8 % in IS patients at the acute stage, whereas serum miR-338 in IS patients showed a specificity up to 53.2 % and a sensitivity of 71.9 % in the acute stage. Expression levels of let-7e in serum may serve as a useful noninvasive circulating biomarker for the acute stage of ischemic stroke. [ABSTRACT FROM AUTHOR]

The pathology and immunological responses to hemagglutinin (HA) from H7N9 avian influenza viruses in humans remain unclear. The present study aimed to investigate the proinflammatory activity of the HA protein obtained from H7N9 viruses and the mechanisms underlying the homeostasis of microRNAs (miRNAs) in response to inflammatory stimuli. The expression of proinflammatory factors and miRNAs was assayed in the THP-1 cells using reverse transcription-quantitative polymerase chain reaction. Results showed that HA significantly increased the expression of interleukin (IL)-1a, IL-1β and IL-6 in the THP-1 cells. Furthermore, HA and lipopolysaccharide exhibited synergic effects on the expression of IL-1α, IL-1β and IL-6 in the THP-1 cells. Let-7e can target IL-6 and inhibit its expression. Notably, HA significantly increased let-7e expression in THP-1 cells and decreased the let-7e levels in the medium. However, the knockdown of toll-like receptor 4 (TLR4) significantly attenuated the effects of HA. These results indicate that the HA can induce inflammatory stress and may trigger an miRNA-mediated homeostasis response to this stress. The effects of HA appeared to be mediated by the TLR4 pathway. [ABSTRACT FROM AUTHOR]

Beta-adrenoceptor (β- AR) exerts critical regulation of cardiac function. Micro RNAs (mi RNAs) are potentially involved in a variety of biological and pathological processes. This study aimed to investigate the role of mi RNA let-7e in the up-regulation of β1- AR and arrhythmogenesis in acute myocardial infarction ( AMI) in rats. β1- AR expression was significantly up-regulated and let-7a, c, d, e and i were markedly down-regulated in the infarcted heart after 6 and 24 hrs myocardial infarction. Forced expression of let-7e suppressed β1- AR expression at the protein level, without affecting β1- AR m RNA level, in neonatal rat ventricular cells ( NRVCs). Silencing of let-7e by let-7e antisense inhibitor ( AMO-let-7e) enhanced β1- AR expression at the protein level in NRVCs. Administration of the lentivirus vector containing precursor let-7e (len-pre-let-7e) significantly inhibited β1- AR expression in rats, whereas len- AMO-let-7e up-regulated β1- AR relative to the baseline control level, presumably as a result of depression of tonic inhibition of β1- AR by endogenous let-7e. Len-negative control (len- NC) did not produce significant influence on β1- AR expression. Len-pre-let-7e also profoundly reduced the up-regulation of β1- AR induced by AMI and this effect was abolished by len- AMO-let-7e. Importantly, len-pre-let-7e application significantly reduced arrhythmia incidence after AMI in rats and its anti-arrhythmic effect was cancelled by len- AMO-let-7e. Notably, anti-arrhythmic efficacy of len-pre-let-7e was similar to propranolol, a non-selective β- AR blocker and metoprolol, a selective β1- AR blocker. Down-regulation of let-7e contributes to the adverse increase in β1- AR expression in AMI and let-7e supplement may be a new therapeutic approach for preventing adverse β1- AR up-regulation and treating AMI-induced arrhythmia. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is a highly invasive neurological malignancy with poor prognosis. LncRNA-GAS5 (growth arrest-specific transcript 5) is a tumor suppressor involved in multiple cancers. In this study, we explored the clinical significance, biological function, and underlying mechanisms of GAS5 in GBM. We showed that lncRNA-GAS5 expression decreased in high-grade glioma tissues and cells, which might be associated with poor prognosis. GAS5 overexpression lowered cell viability, suppressed GBM cell migration and invasion, and impaired the stemness and proliferation of glioma stem cells (GSCs). We further discovered that GAS5 inhibited the viability of glioma cells through miR-let-7e and miR-125a by protecting SPACA6 from degradation. Moreover, GAS5 played an anti-oncogenic role in GBM through the combined involvement of let-7e and miR-125a in vivo and in vitro . Notably, these two miRNAs block the IL-6/STAT3 pathway in tumor tissues extracted from a xenograft model. Taken together, our study provides evidence for an important role of GAS5 in GBM by affecting the proliferation and migration of GSCs, thus providing a new potential prognostic biomarker and treatment strategy for GBM., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wu, Ren, Zhao, Li, Jia, Wu, Dou, Fei, Huan, He, Wang, Lv, Wang, Wang, Zhao, Fei and Li.)

Abstract: This study aimed to investigate the role and mechanism of action of microRNA (miR) let-7e in PC12 cells undergoing apoptosis following anoxia/reoxygenation (A/R) injury. The putative binding site of let-7e in the 3′ UTR of caspase-3 (Casp3) mRNA was analyzed using the miRanda algorithm. Precursor let-7e (pre-miRNA), let-7e miR and anti-let-7e oligonucleotides were transfected into PC12 cells, which were then subjected to A/R injury. The levels of Casp3 mRNA and let-7e miRNA, the total protein levels of Casp3, Casp8 and Casp9 and levels of cellular apoptosis were measured. It was found that let-7e expression in PC12 cells was decreased, whereas the expression of Casp3 was significantly increased after A/R injury. The transfection of pre-miRNA or let-7e miR into PC12 cells decreased Casp3 expression levels and cellular apoptosis following A/R injury, while co-transfection of anti-let-7e strikingly alleviated the effects of let-7e miR. These results indicate that let-7e may protect PC12 cells against apoptosis following A/R injury by negatively regulating the expression of Casp3. [Copyright &y& Elsevier]

Abstract: To understand the role of miRNAs in the molecular mechanisms of temporal lobe epilepsy (TLE), we investigated the changes in microRNA (miRNA) expression profiles of chronic TLE rat models. MiRNAs microarray analysis results showed that 125 miRNAs were detected in the hippocampus of lithium-pilocarpine-induced TLE rats and normal rats. Compared with normal rats (control group), 23 of the 125 miRNAs were expressed differentially in TLE rats including 5 down-regulated miRNAs (let-7e included) and 18 up-regulated miRNAs (miR-23a/b included). Furthermore, let-7e and miR-23a/b analysis in rat hippocampus were performed by real-time quantitative polymerase chain reaction at 0h, 1h, 6h, 12h, 24h, 2days, 7days,10days, 30days,50days after induction of status epilepticus (SE). let-7e was detected down-regulated expression at 0h, 1h, 6h, 2days, 7days, 50days after SE and up-regulated expression at 12h, 24h, 10days, 30days after SE, which was significantly up-regulated expression at 24h after SE (10.49 folds, P <0.01). miR-23a/b was detected down-regulated at 0h, 1h, 6h, 12h, 2days, 7days, 10days, 30days after SE and significantly up-regulated at 24h (4.49 folds P <0.01), 50d (2.4 folds, P <0.01) after SE. TLE alters the expression levels of a subset of miRNAs in the hippocampus and these deregulated miRNAs may be involved in the pathogenesis of epilepsy directly or indirectly. Also the temporal change of the let-7e and miR-23a/b expression in the epileptogenesis indicated their underlying functions on TLE. [Copyright &y& Elsevier]

Objective To detect the expression changes of let-7e and miR-23 in the hippocampus tissues of rats with temporal lobe epilepsy (TLE) at different time points after status epilepticus (SE). Methods A total of 160 rats were randomly divided into the control group (n = 10) which was injected with normal saline,and the TLE group (n = 150) which was induced by lithium-pilocarpine. TLE group was divided into 10 subgroups by different time points (0 hour, 1hour, 6 hours, 12 hours, 1 day, 2 days, 7 days, 14 days, 30 days and 50 days) after SE and each subgroup was consist of 15 rats. The real-time fluorescent quantitative PCR was performed to detect the expression changes of let-7e and miR-23 in all rats. Results The relative expression levels of let-7e in the TLE subgroups were 0. 61,0. 84,0. 85,1. 40,10. 74,0. 71,0. 65,1. 52,1. 69 and 0. 13 at 0 h,1 h,6 h,12 h,1 d,2 d,7 d,14 d,30 d and 50 d. When we compared with that of the normal saline group, significant differences were found (all P < 0. 05). The relative expression levels of miR-23 in the TLE subgroups were 0. 27,0. 31,0. 41,0. 39,4. 49,0. 21,0. 18,0. 12,0. 83 and 2. 4 at 0 h,1 h,6 h,12 h,1 d,2 d,7 d,14 d, 30 d and 50 d. When we compared with that of the normal saline group, significant differences were found (all P < 0. 05). Conclusions The expression of let-7e and miR-23 in the hippocampus of TLE rats was first up-regulated and reached the peak value at 24 h after SE and then it began to down-regulate. A second up-regulated expression was seen from 10 d to 30 d after SE with let-7e and from 30 d to 50 d with miR-23. [ABSTRACT FROM AUTHOR]

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in reproductive-aged women, and its pathogenesis is still under debate. Recent studies suggest crucial roles for microRNAs (miRNAs) in PCOS development. The let-7 family miRNAs constitute the most abundant miRNAs in human granulosa cells (GCs), and plays an important role in follicular development. However, research on the let-7e implications of the non-hyperandrogenic (non-HA) phenotype remains unclear. This study aimed at determining the role of let-7e in the progression of PCOS. We performed quantitative real-time PCR to examine the levels of let-7e in fifty-two non-HA PCOS patients and fifty-two controls. A receiver operating characteristic (ROC) curve were used to reveal the diagnostic value of let-7e in non-HA PCOS. Using an immortalized human granulosa cell line, KGN, we investigated the influence of let-7e on cell proliferation and autophagy. Our data substantiated the expression of let-7e was significantly increased in non-HA PCOS group, and associated with an increased antral follicle count. The ROC curve indicated a major separation between non-HA PCOS group and the control group. Let-7e knockdown suppressed cell proliferation and enhanced cell autophagy by activating p21 pathway. Conversely, let-7e overexpression promoted cell proliferation and inhibited cell autophagy by suppressing p21 pathway. Our results indicate that increased let-7e levels in non-HA PCOS GCs may contribute to excessive follicular activation and growth, thereby involving in the pathogenesis of PCOS. Let-7e may thus be a potential therapeutic target in non-HA PCOS. • Let-7e was up-regulated in the granulosa cells of patients with non-hyperandrogenism PCOS. • Let-7e expression levels were positively associated with antral follicle count. • Let-7e testing may be a candidate for non-hyperandrogenism PCOS diagnosis. • Let-7e promoted granulosa cell proliferation by restraining p21 signaling pathway. • Let-7e inhibited granulosa cell autophagy by restraining p21 signaling pathway. [ABSTRACT FROM AUTHOR]

MicroRNAs are endogenous non-coding RNAs that are involved in numerous biological processes through regulation of gene expression. The aim of our study was to determine the ability of several miRNAs to predict mortality and response to antiplatelet treatment among T2DM patients. Two hundred fifty-two patients with diabetes were enrolled in the study. Among the patients included, 26 (10.3%) patients died within a median observation time of 5.9 years. The patients were receiving either acetylsalicylic acid (ASA) 75 mg (65%), ASA 150 mg (15%) or clopidogrel (19%). Plasma miR-126, miR-223, miR-125a-3p and Let-7e expressions were assessed by quantitative real time PCR and compared between the patients who survived and those who died. Adjusted Cox-regression analysis was used for prediction of mortality. Differential miRNA expression due to different antiplatelet treatment was analyzed. After including all miRNAs into one multivariate Cox regression model, only miR-126 was predictive of future occurrence of long-term all-cause death (HR = 5.82, 95% CI: 1.3–24.9; p = 0.024). Furthermore, miR-126, Let-7e and miR-223 expressions in the clopidogrel group were significantly higher than in the ASA group (p = 0.014; p = 0.013; p = 0.028, respectively). To conclude, miR-126 expression is a strong and independent predictor of long-term all-cause mortality among patients with T2DM. Moreover, miR-223, miR-126 and Let-7e present significant interactions with antiplatelet treatment regimens and clinical outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: For intestinal localized high-risk gastrointestinal stromal tumors (GIST) patients' new molecular biomarkers are urgently needed for a more accurate prognosis. In our study, miRNA profiling analyses was planned to explore new molecular biomarkers with potential prognostic role in this clinical context. Our data, revealed that 39 microRNAs (miRNAs) were significantly deregulated when comparing patients with disease relapsed versus non-relapsed cases. The underexpression of a specific miRNA let-7e and the overexpression of 4 of its target genes (ACVR1B, CASP3, COL3A1 and COL5A2) correlated significantly with worse relapse-free survival. Overall, our results suggest that miRNA profiling is a potential molecular tool useful for a more accurate prognosis for intestinal localized high-risk GIST patients. MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression at the post-transcriptional level, and they have been described as being associated with tumor prognosis. Here, miRNA profiling was planned to explore new molecular prognostic biomarkers in localized intestinal high-risk GIST. Paraffin tumor blocks of 14 and 86 patients were used in the discovery and expansion sets, respectively. GeneChip miRNA v3.0 was employed to identify the miRNAs differentially expressed between relapsed and non-relapsed patient samples, which were validated in the expansion set, by qRT-PCR. RT2 Profiler PCR Array was used for the screening of let-7e targets. Expression levels were correlated with relapse-free survival and overall survival. In the discovery set, 39 miRNAs were significantly deregulated, let-7e and miR-550 being the most underexpressed and overexpressed miRNAs in the relapsed group, respectively. In the expansion set, the underexpression of let-7e or the overexpression of 4 of its target genes (ACVR1B, CASP3, COL3A1, and COL5A2) were statistically associated with worse relapse-free survival. The expression of let-7e and 4 of its target genes are potential prognostic biomarkers in high-risk localized intestinal GIST. The expression of these genes is a potential molecular tool useful for a more accurate prognosis in this subset of GIST patients. [ABSTRACT FROM AUTHOR]

Excessive pulmonary inflammatory response is critical in the development of acute lung injury (ALI). Previously, microRNAs (miRNAs) have been recognized as an important regulator of inflammation in various diseases. However, the effects and mechanisms of miRNAs on inflammatory response in ALI remain unclear. Herein, we tried to screen miRNAs in the processes of ALI and elucidate the potential mechanism. Using a microarray assay, microRNA let-7e (let-7e) was chose as our target for its reported suppressive roles in several inflammatory diseases. Down-regulation of let-7e by antagomiR-let-7e injection attenuated LPS-induced acute lung injury. We also found that antagomiR-let-7e could obviously improve the survival rate in ALI mice. Moreover, antagomiR-let-7e treatment reduced the production of proinflammatory cytokines (i.e., TNF-α, IL-1β and IL-6) in bronchoalveolar lavage fluid (BALF) of LPS-induced ALI mice. Luciferase reporter assays confirmed that suppressor of cytokine signaling 1 (SOCS1), a powerful attenuator of nuclear factor kappa B (NF-κB) signaling pathway, was directly targeted and suppressed by let-7e in RAW264.7 cells. In addition, it was further observed that SOCS1 was down-regulated, and inversely correlated with let-7e expression levels in lung tissues of ALI mice. Finally, down-regulation of let-7e suppressed the activation of NF-κB pathway, as evidenced by the reduction of p-IκBα, and nuclear p-p65 expressions in ALI mice. Collectively, our findings indicate that let-7e antagomir protects mice against LPS-induced lung injury via repressing the pulmonary inflammation though regulation of SOCS1/NF-κB pathway, and let-7e may act as a potential therapeutic target for ALI., (© 2021 The Author(s).)

Chronic inflammation and abnormalities in Toll-like receptor (TLR) signaling pathways are associated with major depressive disorder (MDD). Our previous work reported that impaired negative regulators for the TLR pathways are associated with MDD. This study aimed to assess the association between the severity of depression and the intracellular microRNAs that regulate TLR4 signaling in both peripheral blood mononuclear cells (PBMCs) and monocytes from MDD patients. The severity of MDD before and after antidepressant treatment was determined by the 17-item Hamilton Depression Rating Scale, and quantitative RT-PCR was used to measure the levels of intracellular regulatory microRNAs, including let-7e, miR-21-5p miR-145, miR-223, miR-146a, and miR-155, in PBMCs and monocytes isolated from 43 healthy controls and 84 patients with MDD before and after treatment with antidepressants. Assays of PBMCs showed that the levels of let-7e, miR-146a, and miR-155 were lower in MDD patients than in healthy controls and were significantly higher after than before treatment in the 69 patients who completed treatment with antidepressants for four weeks. Levels of miR-146a and miR-155 in monocytes were lower in MDD patients than in controls and were increased in the former after antidepressant treatment. Multiple linear regression analyses found that let-7e and miR-146a expression before treatment was inversely correlated with severity of depression, whereas miR-155 before treatment was directly correlated with severity of depression. These findings suggest that intracellular regulatory microRNAs which regulate TLR4 signaling are aberrantly expressed in patients with MDD and that these levels are ameliorated by antidepressant treatment. [ABSTRACT FROM AUTHOR]

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MAPK-activated protein kinase 2 (MK2) plays a critical role in the development of inflammation. However, the modulatory mechanisms in macrophage activation and acute lung injury (ALI) have not been completely defined. Here, we reported that MK2-deficient mice (MK2 -/- ) protected against sepsis-induced ALI. In response to lipopolysaccharide (LPS) challenge, MK2 -/- mice and myeloid cell-specific MK2 conditional knockout mice (MK2 Lyz2-KO ) exhibited attenuated inflammatory response, especially producing fewer amounts of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and macrophage inflammatory protein 2 (MIP-2). LPS treatment in vitro resulted in reduced cytokine expression in MK2 -/- bone marrow-derived macrophages (BMDMs). Furthermore, we found that LPS-induced microRNA lethal-7e ( let-7e) expression was significantly increased in MK2 -/- macrophages. Transfection of let-7e antagomirs into MK2 -/- BMDM rescued LPS-induced expression of TNF-α, IL-6, and MIP-2. In contrast, transfection of let-7e mimics into MK2 +/+ BMDM decreased cytokine expression. Meanwhile, LPS-induced phosphorylation of cAMP response element-binding (CREB) protein, a substrate of MK2, was downregulated in MK2 -/- BMDMs. Lin28, an inhibitory molecule of let-7, was significantly reduced in MK2 -/- macrophages. Our results suggested that MK2 boosts LPS-induced macrophage activation and ALI via increasing activation of CREB and consequently, the expression of Lin28 and downregulation of let-7e.

Purpose: Previous studies have demonstrated that let-7e is associated with inflammatory responses. To date, the roles and mechanisms of let-7e have not been completely revealed.Therefore, we aim to identify proteins associated with let-7e overexpression and explore their functions in the immune responses, including in cytokine production., Experimental Design: High-throughput isobaric tag for relative and absolute quantitation (iTRAQ) technology is used to provide the first genome-wide study of THP-1 cells transfected with let-7e mimic followed by lipopolysaccharide (LPS) stimulation. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database and KEGG pathway enrichment analyses are used to analyze a large number of differentially expressed proteins (DEPs) associated with let-7e overexpression or LPS stimulation. Quantitative reverse transcription PCR (qRT-PCR) and 50% tissue culture infective dose (TCID50) assays are processed to confirm the relationship of let-7e and dengue virus replication., Results: iTRAQ results show that let-7e is associated with the expression of anti-viral proteins. What's more, calcineurin subunit B type 1, an anti-tumor factor, is upregulated by let-7e after LPS stimulation. KEGG analyses identify that some DEPS associated with let-7e overexpression are involved in the measles and influenza A pathways, and LPS-stimulated proteins in THP-1 cells are mainly enriched in transcriptional misregulation in cancer pathway and hippo signaling pathway (multiple species). The results of qRT-PCRand TCID50 show that let-7e promotes dengue virus replication, which is in agreement with the iTRAQ results., Conclusions and Clinical Relevance: These results provide molecular insights into the regulatory mechanisms of let-7e in cytokine expression, virus replication, and anti-tumor function., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Background: Resistance to platinum-based chemotherapy remains a great challenge for ovarian cancer treatment. The human let-7 family contains 13 members located on nine different chromosomes, and most members have been implicated in the modulation of drug sensitivity in cancers. Our previous study showed that deregulation of let-7e in epithelial ovarian cancer (EOC) promoted the development of resistance to cisplatin. In the present study, we aimed to investigate the underlying mechanism and further evaluate the clinical value of let-7e in predicting chemo-response and prognosis in EOC., Results: In situ hybridization assays revealed a significantly decreased expression of let-7e in chemo-resistant EOC tissues compared with chemo-sensitive cases. Transfection with let-7e agomir sensitized EOC cells to cisplatin, down-regulated BRCA1 and Rad51 expression, and repressed the repair of cisplatin-induced DNA double strand break, while let-7e inhibitor exerted the opposite effects. In human EOC tissues, BRCA1 and Rad51 levels were increased in the chemo-resistant group compared with the sensitive group and were negatively correlated with let-7e. Low let-7e and high Rad51 were significantly associated with poor progression-free survival and overall survival and multivariate regression analyses showed that let-7e was an independent predictor for overall survival and chemotherapy response in EOC. Receiver operating characteristic analysis indicated that let-7e level was highly predictive of resistance to platinum-taxane chemotherapy with an area under the curve of 0.826., Conclusions: In EOC, low let-7e leads to activation of BRCA1 and Rad51 expression and subsequent enhancement of DSB repair, which in turn results in cisplatin-resistance. Let-7e is a potential predictor for survival and chemo-response in EOC and re-expression of let-7e might be an effective strategy for overcoming chemo-resistance.

Nuclear paraspeckle assembly transcript 1 (NEAT1), a long non-coding RNA, promotes oncogenesis in various tumors, including human gliomas. Herein, we studied the expression and function of NEAT1 in glioma stem cells (GSCs). Quantitative real-time PCR demonstrated that NEAT1 was upregulated in GSCs. NEAT1 knockdown inhibited GSC cell proliferation, migration and invasion and promoted GSC apoptosis. A potential binding region between NEAT1 and microRNA let-7e was confirmed by dual-luciferase assays. Upregulation of NEAT1 reduced the expression of let-7e, and there was reciprocal repression between NEAT1 and let-7e in an Argonaute 2-dependent manner. Let-7e expression was lower expression in glioblastoma tissues and GSCs than in normal brain tissues and cells. Restoration of let-7e suppressed tumor function by inhibiting proliferation, migration and invasion while promoting apoptosis in GSCs. NEAT1 knockdown and let-7e overexpression both reduced NRAS protein expression. NRAS was identified as a direct target of let-7e and promoted oncogenesis in GSCs. As NEAT1 promoted oncogenesis by downregulating let-7e expression, both of these genes could be considered for application in glioma therapy., Competing Interests: The authors declare no conflict of interest.