miR-181a-5p regulates the proliferation and apoptosis of glomerular mesangial cells by targeting KLF6

The RNA binding protein IGF2BP2/IMP2 alters the cargo of cancer cell-derived extracellular vesicles supporting tumor-associated macrophages

BACKGROUND

Tumor cells release extracellular vesicles (EVs) that contribute to the polarization of macrophages towards tumor-associated macrophages (TAMs). High expression levels of the RNA binding protein IGF2BP2/IMP2 are correlated with increased tumor cell proliferation, invasion, and poor prognosis in the clinic. However, there is a lack of understanding of whether IMP2 affects the cargo of cancer cell-derived EVs, thereby modulating macrophage polarization.

METHODS

EVs were isolated from IMP2-expressing HCT116 parental cells (WT) and CRISPR/Cas9 IMP2 knockout (KO) cells. EVs were characterized according to MISEV guidelines, microRNA cargo was assessed by microRNA-Seq, and the protein cargo was analyzed by proteomics. Primary human monocyte-derived macrophages (HMDMs) were polarized by EVs, and the expression of genes and surface markers was assessed using qPCR and flow cytometry, respectively. Morphological changes of macrophages, as well as the migratory potential of cancer cells, were assessed by the Incucyte® system and macrophage matrix degradation potential by zymography. Changes in the metabolic activity of macrophages were quantified using a Seahorse® analyzer. For in vivo studies, EVs were injected into the yolk sac of zebrafish larvae, and macrophages were isolated by fluorescence-activated cell sorting.

RESULTS

EVs from WT and KO cells had a similar size and concentration and were positive for 25 vesicle markers. The expression of tumor-promoting genes was higher in macrophages polarized with WT EVs than KO EVs, while the expression of TNF and IL6 was reduced. A similar pattern was observed in macrophages from zebrafish larvae treated in vivo. WT EV-polarized macrophages showed a higher abundance of TAM-like surface markers, higher matrix degrading activity, as well as a higher promotion of cancer cell migration. MicroRNA-Seq revealed a significant difference in the microRNA composition of WT and KO EVs, particularly a high abundance of miR-181a-5p in WT EVs, which was absent in KO EVs. Inhibitors of macropinocytosis and phagocytosis antagonized the delivery of miR-181a-5p into macrophages and the downregulation of the miR-181a-5p target DUSP6. Proteomics data showed differences in protein cargo in KO vs. WT EVs, with the differentially abundant proteins mainly involved in metabolic pathways. WT EV-treated macrophages exhibited a higher basal oxygen consumption rate and a lower extracellular acidification rate than KO EV-treated cells.

CONCLUSION

Our results show that IMP2 determines the cargo of EVs released by cancer cells, thereby modulating the EVs' actions on macrophages. Expression of IMP2 is linked to the secretion of EVs that polarize macrophages towards a tumor-promoting phenotype.

Chiisanoside Mediates the Parkin/ZNF746/PGC-1α Axis by Downregulating MiR-181a to Improve Mitochondrial Biogenesis in 6-OHDA-Caused Neurotoxicity Models In Vitro and In Vivo: Suggestions for Prevention of Parkinson's Disease

The degeneration of dopamine (DA) neurons is known to be associated with defects in mitochondrial biogenesis caused by aging, environmental factors, or mutations in genes, leading to Parkinson's disease (PD). As PD has not yet been successfully cured, the strategy of using small molecule drugs to protect and restore mitochondrial biogenesis is a promising direction. This study evaluated the efficacy of synthetic chiisanoside (CSS) identified in the leaves of Acanthopanax sessiliflorus to prevent PD symptoms. The results show that in the 6-hydroxydopamine (6-OHDA) model, CSS pretreatment can effectively alleviate the reactive oxygen species generation and apoptosis of SH-SY5Y cells, thereby lessening the defects in the C. elegans model including DA neuron degeneration, dopamine-mediated food sensitivity behavioral disorders, and shortened lifespan. Mechanistically, we found that CSS could restore the expression of proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α), a key molecule in mitochondrial biogenesis, and its downstream related genes inhibited by 6-OHDA. We further confirmed that this is due to the enhanced activity of parkin leading to the ubiquitination and degradation of PGC-1α inhibitor protein Zinc finger protein 746 (ZNF746). Parkin siRNA treatment abolished this effect of CSS. Furthermore, we found that CSS inhibited 6-OHDA-induced expression of miR-181a, which targets parkin. The CSS's ability to reverse the 6-OHDA-induced reduction in mitochondrial biogenesis and activation of apoptosis was abolished after the transfection of anti-miR-181a and miR-181a mimics. Therefore, the neuroprotective effect of CSS mainly promotes mitochondrial biogenesis by regulating the miR-181a/Parkin/ZNF746/PGC-1α axis. CSS potentially has the opportunity to be developed into PD prevention agents.

The role of microRNAs in pathophysiology and diagnostics of metabolic complications in obstructive sleep apnea patients

Obstructive sleep apnea (OSA) is one of the most common sleep disorders, which is characterized by recurrent apneas and/or hypopneas occurring during sleep due to upper airway obstruction. Among a variety of health consequences, OSA patients are particularly susceptible to developing metabolic complications, such as metabolic syndrome and diabetes mellitus type 2. MicroRNAs (miRNAs) as epigenetic modulators are promising particles in both understanding the pathophysiology of OSA and the prediction of OSA complications. This review describes the role of miRNAs in the development of OSA-associated metabolic complications. Moreover, it summarizes the usefulness of miRNAs as biomarkers in predicting the aforementioned OSA complications.

An in vitro approach to understand contribution of kidney cells to human urinary extracellular vesicles

Extracellular vesicles (EV) are membranous particles secreted by all cells and found in body fluids. Established EV contents include a variety of RNA species, proteins, lipids and metabolites that are considered to reflect the physiological status of their parental cells. However, to date, little is known about cell-type enriched EV cargo in complex EV mixtures, especially in urine. To test whether EV secretion from distinct human kidney cells in culture differ and can recapitulate findings in normal urine, we comprehensively analysed EV components, (particularly miRNAs, long RNAs and protein) from conditionally immortalised human kidney cell lines (podocyte, glomerular endothelial, mesangial and proximal tubular cells) and compared to EV secreted in human urine. EV from cell culture media derived from immortalised kidney cells were isolated by hydrostatic filtration dialysis (HFD) and characterised by electron microscopy (EM), nanoparticle tracking analysis (NTA) and Western blotting (WB). RNA was isolated from EV and subjected to miRNA and RNA sequencing and proteins were profiled by tandem mass tag proteomics. Representative sets of EV miRNAs, RNAs and proteins were detected in each cell type and compared to human urinary EV isolates (uEV), EV cargo database, kidney biopsy bulk RNA sequencing and proteomics, and single-cell transcriptomics. This revealed that a high proportion of the in vitro EV signatures were also found in in vivo datasets. Thus, highlighting the robustness of our in vitro model and showing that this approach enables the dissection of cell type specific EV cargo in biofluids and the potential identification of cell-type specific EV biomarkers of kidney disease.

Integrated analysis of mRNA and microRNA expression profiles in hepatopancreas of Litopenaeus vannamei under acute exposure to MC-LR

Intensive shrimp farming is often threatened by microcystins Hepatopancreas is the primary target organ of MCs in shrimp. To investigate the response of hepatopancreas to acute MC-LR exposure, the expression profiles of RNA-seq and miRNA-seq in the hepatopancreas of L. vannamei were determined, and data integration analysis was performed at 72 h after MC-LR injection. The expression of 5 DEGs and three DEMs were detected by Quantitative PCR (qPCR). The results showed that the cumulative mortality rate of shrimp in MC-LR treatment group was 41.1%. A total of 1229 differentially expressed genes (844 up- and 385 down-regulated) and 86 differentially expressed miRNAs (40 up- and 46 down-regulated) were identified after MC-LR exposure. Functional analysis indicated that DEGs is mainly involved in the oxidative activity process in molecular functional categories, and proteasome was the most enriched KEGG pathway for mRNAs profile. According to the functional annotation of target genes of DEMs, protein binding was the most important term in the GO category, and protein processing in endoplasmic reticulum (ER) was the most enriched KEGG pathway. The regulatory network of miRNAs and DEGs involved in the pathway related to protein degradation in endoplasmic reticulum was constructed, and miR-181-5p regulated many genes in this pathway. The results of qPCR showed that there were significant differences in the expression of five DEGs and three DEMs, which might play an important role in the toxicity and hepatopancreas detoxification of MC-LR in shrimp. The results revealed that MC-LR exposure affected the degradation pathway of misfolded protein in ER of L. vannamei hepatopancreas, and miR-181-5p might play an important role in the effect of MC-LR on the degradation pathway of misfolded protein.

LncRNA NUTM2A-AS1 aggravates the progression of hepatocellular carcinoma by activating the miR-186-5p/KLF7-mediated Wnt/beta-catenin pathway

Emerging evidence has uncovered that noncoding RNAs (ncRNAs) contribute to the development of hepatocellular carcinoma (HCC). Nevertheless, the functions of the majority of long ncRNAs (lncRNAs) in HCC are unknown. Here, we intend to probe the function of lncRNA NUTM2A-AS1 in the evolvement of HCC and the related mechanism. Expression levels of lncRNA NUTM2A-AS1, miR-186-5p and KLF7 mRNA in HCC tissues and adjacent non-tumor tissues were monitored. Gain- or loss-of-function assays were utilized to investigate the biological functions of lncRNA NUTM2A-AS1, miR-186-5p and KLF7 in HCC cell lines (including HCCLM3 and Huh7). Western blot was implemented for the detection of the epithelial-mesenchymal transition (EMT)-related proteins (including E-cadherin, Vimentin and Snail), KLF7, Wnt, β-catenin, and stemness-related proteins (Nanog, OCT4, YKL40, and CD133). Furthermore, the targeted associations between lncRNA NUTM2A-AS1, miR-186-5p, and KLF7 were verified by bioinformatics analysis, dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. As a result, lncRNA NUTM2A-AS1 and KLF7 profiles were heightened in the HCC tissues versus adjacent normal tissues, while miR-186-5p had the opposite expression tendency. Up-regulation of lncRNA NUTM2A-AS1 was related to tumor size, advanced tumor stage, and lymph node metastasis of HCC patients. Functionally, overexpression of lncRNA NUTM2A-AS1 heightened HCC cells' growth, invasion, EMT, and stemness and repressed their apoptosis by activating the Wnt/β-catenin pathway. In contrast, up-regulation of miR-186-5p or inhibition of KLF7 had reverse effects. In vivo, lncRNA NUTM2A-AS1 overexpression facilitated tumor growth and EMT, accompanied by declined miR-186-5p levels and enhanced KLF7 expression. The mechanistic studies revealed that miR-186-5p served as a common target of lncRNA NUTM2A-AS1 and KLF7. As hinted by the rescue experiments, NUTM2A-AS1 partly abated miR-186-5p-mediated anti-tumor effects in HCC cells, whereas KLF7 knockdown reversed the promotive effects of NUTM2A-AS1. LncRNA NUTM2A-AS1 accelerated the evolution of HCC by up-regulating the KLF7/Wnt/beta-catenin pathway through sponging miR-186-5p.

Kruppel-Like Factor (KLF6) Regulates Oxidative Stress and Apoptosis of Human Retinal Pigment Epithelial Cells Induced by High Glucose Through Transcriptional Regulation of USP22 and the Downstream SIRT1/Nrf2 Pathway

Oxidative stress and apoptosis play an important role in diabetic retinopathy (DR). KLF6 and its transcriptional regulator USP22 are abnormally expressed in DR, but the specific role and mechanism have not been reported. In this paper, we will discuss the specific roles and mechanisms of KLF6 and USP22 on oxidative stress and apoptosis in DR. In this study, RT-qPCR and western blot were used to detect the expression of KLF6 and USP22 in ARPE-19 cells. Subsequently, after KLF6 was overexpressed and USP22 expression was inhibited by cell transfection, the oxidative stress and apoptosis related indexes were detected by CCK-8, ELISA, TUNEL and other techniques to explore the mechanism. In addition, we used luciferase and ChIP to detect the association between KLF6 and USP22. Finally, the expression of proteins related to the SIRT1/Nrf2 pathway was detected by western blot. The results showed that silencing USP22 increased the activity, and inhibited apoptosis and oxidative stress of ARPE-19 cells induced by high glucose (HG). KLF6 transcriptionally activates USP22. Overexpression of KLF6 reversed the protective effects of silencing USP22 on HG-induced ARPE-19 cells against apoptosis and antioxidant stress, which may be achieved by regulating the SIRT1/Nrf2 pathway. In conclusion, KLF6 regulated oxidative stress and apoptosis of ARPE-19 cells induced by high glucose through transcriptional regulation of USP22 and the downstream SIRT1/Nrf2 pathway.

MicroRNA-181a-5p Promotes Osteosarcoma Progression via PTEN/AKT Pathway

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents with poor prognosis. MicroRNA-181a-5p (miR-181a-5p) is involved in the progression of various tumors; however, its role and underlying mechanism in osteosarcoma remains unclear. In this study, we found that miR-181a-5p was upregulated in human osteosarcoma cells and tissues. miR-181a-5p mimic significantly promoted, while miR-181a-5p inhibitor blocked the proliferation, colony formation, migration, invasion, and cell cycle progression of osteosarcoma cells. Mechanistically, miR-181a-5p bound to the 3′-untranslational region of phosphatase and tensin homolog (PTEN) and reduced its protein expression, thereby activating protein kinase B (PKB/AKT) pathway. Either PTEN overexpression or AKT inhibition notably blocked the tumor-promoting effects of miR-181a-5p. Moreover, we observed that miR-181a-5p mimic further inhibited growth of human osteosarcoma cells in the presence of adriamycin or cisplatin. Overall, miR-181a-5p promotes osteosarcoma progression via PTEN/AKT pathway and it is a promising therapeutic target to treat osteosarcoma.

MiR-181 enhances proliferative and migratory potentials of retinal endothelial cells in diabetic retinopathy by targeting KLF6

PURPOSE

We aimed to uncover the role of microRNA-181 (miR-181) in the disease onset of diabetic retinopathy (DR) and its underlying mechanism.

METHODS

MiR-181 levels in plasma and aqueous humor samples of non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR) and healthy subjects were analyzed by microarray and quantitative real-time polymerase chain reaction (qRT-PCR). Proliferative and migrative capacities of human retinal endothelial cells (hRECs) regulated by miR-181 were assessed. The binding between miR-181 and kruppel-like factor 6 (KLF6) was verified by dual-luciferase reporter assay.

RESULTS

MiR-181 was upregulated in plasma and aqueous humor samples of NPDR and PDR patients. Overexpression of miR-181 stimulated hRECs to proliferate and migrate. KLF6 was the downstream gene binding miR-181, which was involved in the regulation of hRECs by miR-181.

CONCLUSIONS

MiR-181 is upregulated in plasma and aqueous humor of DR patients. It enhances proliferative and migratory potentials of retinal endothelial cells by targeting KLF6.

Exosomal lncRNA-p21 derived from mesenchymal stem cells protects epithelial cells during LPS-induced acute lung injury by sponging miR-181

Long noncoding RNAs (lncRNAs) act as essential regulators of various diseases. However, the functions of lncRNAs in sepsis-induced acute lung injury (SALI) remain unclear. Here, we found that lipopolysaccharide could upregulate lncRNA-p21 expression in mesenchymal stem cells (MSCs) in a time- and dose-dependent manner and that lncRNA-p21 was packaged into exosomes. Furthermore, we demonstrated that treatment with exosomal lncRNA-p21 could increase the expression of sirtuin 1 (SIRT1) to protect MLE-12 cells from apoptosis during sepsis. Moreover, we identified SIRT1 as a direct target of miR-181 and found that the level of SIRT1 was negatively correlated with the level of miR-181. The luciferase reporter assay also confirmed the negative correlation between the levels of miR-181 and lncRNA-p21. Our results showed that the lncRNA-p21-induced downregulation of miR-181 might suppress epithelial cell apoptosis and alleviate lung tissue injury by upregulating SIRT1 expression, suggesting the potential therapeutic effects of lncRNA-p21 on SALI. In conclusion, we found that the novel lncRNA-p21/miR-181/SIRT1 pathway may play an important role in the progression of SALI, and MSC-derived exosomes may be a new therapeutic strategy for this disease.

Declined miR-181a-5p expression is associated with impaired natural killer cell development and function with aging

MicroRNAs (miRNAs) regulate gene expression and thereby influence cell development and function. Numerous studies have shown the significant roles of miRNAs in regulating immune cells including natural killer (NK) cells. However, little is known about the role of miRNAs in NK cells with aging. We previously demonstrated that the aged C57BL/6 mice have significantly decreased proportion of mature (CD27^- CD11b⁺ ) NK cells compared with young mice, indicating impaired maturation of NK cells with aging. Here, we performed deep sequencing of CD27⁺ NK cells from young and aged mice. Profiling of the miRNome (global miRNA expression levels) revealed that 49 miRNAs displayed a twofold or greater difference in expression between young and aged NK cells. Among these, 30 miRNAs were upregulated and 19 miRNAs were downregulated in the aged NK cells. We found that the expression level of miR-l8la-5p was increased with the maturation of NK cells, and significantly decreased in NK cells from the aged mice. Knockdown of miR-181a-5p inhibited NK cell development in vitro and in vivo. Furthermore, miR-181a-5p is highly conserved in mice and human. MiR-181a-5p promoted the production of IFN-γ and cytotoxicity in stimulated NK cells from both mice and human. Importantly, miR-181a-5p level markedly decreased in NK cells from PBMC of elderly people. Thus, our results demonstrated that the miRNAs profiles in NK cells change with aging, the decreased level of miR-181a-5p contributes to the defective NK cell development and function with aging. This opens new strategies to preserve or restore NK cell function in the elderly.

Phenytoin Inhibits Cell Proliferation through microRNA-196a-5p in Mouse Lip Mesenchymal Cells

Cleft lip (CL) is one of the most common birth defects. It is caused by either genetic mutations or environmental factors. Recent studies suggest that environmental factors influence the expression of noncoding RNAs [e.g., microRNA (miRNA)], which can regulate the expression of genes crucial for cellular functions. In this study, we examined which miRNAs are associated with CL. Among 10 candidate miRNAs (miR-98-3p, miR-101a-3p, miR-101b-3p, miR-141-3p, miR-144-3p, miR-181a-5p, miR-196a-5p, miR-196b-5p, miR-200a-3p, and miR-710) identified through our bioinformatic analysis of CL-associated genes, overexpression of miR-181a-5p, miR-196a-5p, miR-196b-5p, and miR-710 inhibited cell proliferation through suppression of genes associated with CL in cultured mouse embryonic lip mesenchymal cells (MELM cells) and O9-1 cells, a mouse cranial neural crest cell line. In addition, we found that phenytoin, an inducer of CL, decreased cell proliferation through miR-196a-5p induction. Notably, treatment with a specific inhibitor for miR-196a-5p restored cell proliferation through normalization of expression of CL-associated genes in the cells treated with phenytoin. Taken together, our results suggest that phenytoin induces CL through miR-196a-5p induction, which suppresses the expression of CL-associated genes.