Reverse Expression of Aging-Associated Molecules through Transfection of miRNAs to Aged Mice

Extracellular vesicle-encapsulated miR-30c-5p reduces aging-related liver fibrosis

Aging is associated with decreased health span, and despite the recent advances made in understanding the mechanisms of aging, no antiaging drug has been approved for therapy. Therefore, strategies to promote a healthy life in aging are desirable. Previous work has shown that chronic treatment with extracellular vesicles (EVs) from young mice prolongs lifespan in old mice, but the mechanism of action of this effect on liver metabolism is not known. Here we investigated the role of treatment with EVs derived from young sedentary (EV-C) or exercised (EV-EX) mice in the metabolism of old mice and aimed to identify key youthful-associated microRNA (miRNA) cargos that could promote healthy liver function. We found that aged mice treated with either EV-C or EV-EX had higher insulin sensitivity, higher locomotor activity resulting in longer distance traveled in the cage, and a lower respiratory exchange ratio compared to mice treated with EVs from aged mice (EV-A). In the liver, treatment with young-derived EVs reduced aging-induced liver fibrosis. We identified miR-30c in the EVs as a possible youth-associated miRNA as its level was higher in circulating EVs of young mice. Treatment of aged mice with EVs transfected with miR-30c mimic reduced stellate cell activation in the liver and reduced fibrosis compared to EV-negative control by targeting Foxo3. Our results suggest that by delivering juvenile EVs to old mice, we can improve their liver health. Moreover, we identified miR-30c as a candidate for antiaging liver therapy.

Exploration of the Key Genes Involved in Non-alcoholic Fatty Liver Disease and Possible MicroRNA Therapeutic Targets

Background

MicroRNAs (miRNAs) are promising therapeutic agents for non-alcoholic fatty liver disease (NAFLD). This study aimed to identify key genes/proteins involved in NAFLD pathogenesis and progression and to evaluate miRNAs influencing their expression.

Methods

Gene expression profiles from datasets GSE151158, GSE163211, GSE135251, GSE167523, GSE46300, and online databases were analyzed to identify significant NAFLD-related genes. Then, protein-protein interaction networks and module analysis identified hub genes/proteins, which were validated using real-time PCR in oleic acid-treated HepG2 cells. Functional enrichment analysis evaluated signaling pathways and biological processes. Gene-miRNA interaction networks identified miRNAs targeting critical NAFLD genes.

Results

The most critical overexpressed hub genes/proteins included: TNF, VEGFA, TLR4, CYP2E1, ACE, SCD, FASN, SREBF2, and TGFB1 based on PPI network analysis, of which TNF, TLR4, SCD, FASN, SREBF2, and TGFB1 were up-regulated in oleic acid-treated HepG2 cells. Functional enrichment analysis for biological processes highlighted programmed necrotic cell death, lipid metabolic process response to reactive oxygen species, and inflammation. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, the highest adjusted P-value signaling pathways encompassed AGE-RAGE in diabetic complications, TNF, and HIF-1 signaling pathways. In gene-miRNA network analysis, miR-16 and miR-124 were highlighted as the miRNAs exerting the most influence on important NAFLD-related genes.

Conclusion

In silico analyses identified NAFLD therapeutic targets and miRNA candidates to guide further experimental investigation.

Analysis of the therapeutic potential of miR-124 and miR-16 in non-alcoholic fatty liver disease

BACKGROUNDS

Non-alcoholic fatty liver disease (NAFLD) is a common condition affecting >25 % of the population worldwide. This disorder ranges in severity from simple steatosis (fat accumulation) to severe steatohepatitis (inflammation), fibrosis and, at its end-stage, liver cancer. A number of studies have identified overexpression of several key genes that are critical in the initiation and progression of NAFLD. MiRNAs are potential therapeutic agents that can regulate several genes simultaneously. Therefore, we transfected cell lines with two key miRNAs involved in targeting NAFLD-related genes.

METHODS

The suppression effects of the investigated miRNAs (miR-124 and miR-16) and genes (TNF, TLR4, SCD, FASN, SREBF2, and TGFβ-1) from our previous study were investigated by real-time PCR in Huh7 and HepG2 cells treated with oleic acid. Oil red O staining and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay were utilized to assess cell lipid accumulation and cytotoxic effects of the miRNAs, respectively. The pro-oxidant-antioxidant balance (PAB) assay was undertaken for miR-16 and miR-124 after cell transfection.

RESULTS

Following transfection of miRNAs into HepG2, oil red O staining showed miR-124 and miR-16 reduced oleic acid-induced lipid accumulation by 35.2 % and 28.6 % respectively (p < 0.05). In Huh7, miR-124 and miR-16 reduced accumulation by 23.5 % and 31.3 % respectively (p < 0.05) but without impacting anti-oxidant activity. Real-time PCR in HepG2 revealed miR-124 decreased expression of TNF by 0.13-fold, TLR4 by 0.12-fold and SREBF2 by 0.127-fold (p < 0.05). miR-16 decreased TLR4 by 0.66-fold and FASN by 0.3-fold (p < 0.05). In Huh7, miR-124 decreased TNF by 0.12-fold and FASN by 0.09-fold (p < 0.05). miR-16 decreased SCD by 0.28-fold and FASN by 0.64-fold (p < 0.05). MTT assays showed, in HepG2, viability was decreased 24.7 % by miR-124 and decreased 33 % by miR-16 at 72 h (p < 0.05). In Huh7, miR-124 decreased viability 42 % at 48 h and 29.33 % at 72 h (p < 0.05), while miR-16 decreased viability by 32.3 % (p < 0.05).

CONCLUSION

These results demonstrate the ability of miR-124 and miR-16 to significantly reduce lipid accumulation and expression of key pathogenic genes associated with NAFLD through direct targeting. Though this requires further in vivo investigation.

Lack of expression of miR-29a/b1 impairs bladder function in male mice

Lower urinary tract symptoms (LUTS) refer to various urological diseases, and incomplete bladder emptying is common among affected patients. The etiology of LUTS is largely unknown, and investigations of LUTS suggest that bladder fibrosis contributes to pathogenesis of LUTS. MicroRNAs (miRNAs) are short (∼22 nucleotides), non-coding RNAs that repress target gene expression by a combination of mRNA degradation and translation inhibition. The miR-29 family is best known for its anti-fibrotic role in various organs. miR-29 was decreased in bladders of patients with outlet obstruction and a rat model of bladder outlet obstruction, suggesting that miR-29 may contribute to impaired bladder function subsequent to tissue fibrosis. We characterized bladder function in male mice lacking expression of Mir29a and Mir29b-1 (miR-29a/b1). Lack of miR-29a/b1 resulted in severe urinary retention, increased voiding duration and reduced flow rate, and these mice failed to void or voided irregularly during anesthetized cytometry. Collagens and elastin were increased in bladders of mice lacking miR-29a/b1. These findings reveal an important role for miR-29 in bladder homeostasis and suggest the therapeutic potential of miR-29 to improve symptoms in patients with LUTS.

primiReference: a reference for analysis of primary-microRNA expression in single-nucleus sequencing data

Single-nucleus RNA-sequencing technology has revolutionized understanding of nuanced changes in gene expression between cell types within tissues. Unfortunately, our understanding of regulatory RNAs, such as microRNAs (miRNAs), is limited through both single-cell and single-nucleus techniques due to the short length of miRNAs in the cytoplasm and the incomplete reference of longer primary miRNA (pri-miRNA) transcripts in the nucleus. We build a custom reference to align and count pri-miRNA sequences in single-nucleus data. Using young and aged subventricular zone (SVZ) nuclei, we show differential expression of pri-miRNAs targeting genes involved in neural stem cells (NSC) differentiation in the aged SVZ. Furthermore, using wild-type and 5XFAD mouse model cortex nuclei, to validate the use of primiReference, we find cell-type-specific expression of pri-miRNAs known to be involved in Alzheimer's disease (AD). pri-miRNAs likely contribute to NSC dysregulation with age and AD pathology. primiReference is paramount in capturing a global profile of gene expression and regulation in single-nucleus data and can provide key insights into cell-type-specific expression of pri-miRNAs, paving the way for future studies of regulation and pathway dysregulation. By looking at pri-miRNA abundance and transcriptional differences, regulation of gene expression by miRNAs in disease and aging can be further explored.

Emerging role of aging in the progression of NAFLD to HCC

With the aging of global population, the incidence of nonalcoholic fatty liver disease (NAFLD) has surged in recent decades. NAFLD is a multifactorial disease that follows a progressive course, ranging from simple fatty liver, nonalcoholic steatohepatitis (NASH) to liver cirrhosis and hepatocellular carcinoma (HCC). It is well established that aging induces pathological changes in liver and potentiates the occurrence and progression of NAFLD, HCC and other age-related liver diseases. Studies of senescent cells also indicate a pivotal engagement in the development of NAFLD via diverse mechanisms. Moreover, nicotinamide adenine dinucleotide (NAD⁺), silence information regulator protein family (sirtuins), and mechanistic target of rapamycin (mTOR) are three vital and broadly studied targets involved in aging process and NAFLD. Nevertheless, the crucial role of these aging-associated factors in aging-related NAFLD remains underestimated. Here, we reviewed the current research on the roles of aging, cellular senescence and three aging-related factors in the evolution of NAFLD to HCC, aiming at inspiring promising therapeutic targets for aging-related NAFLD and its progression.

MiR-103-3p promotes hepatic steatosis to aggravate nonalcoholic fatty liver disease by targeting of ACOX1

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a major risk factor for hepatocellular carcinoma, and alterations in miRNA expression are related to the development of NAFLD. However, the role of miRNAs in regulating the development of NAFLD is still poorly understood.

METHODS

We used qRT-PCR to detect the level of miR-103-3p in both cell and mouse models of NAFLD. Biochemical assays, DCF-DA assays, Oil red O staining and HE staining were used to detect the role of miR-103-3p in NAFLD development. Target genes of miR-103-3p were predicted using the TargetScan database and verified by qRT-PCR, western blot and dual-luciferase assays.

RESULTS

The expression of miR-103-3p increased in both NAFLD model cells and liver tissues from the NAFLD mouse model. Inhibition of miR-103-3p significantly alleviated the accumulation of lipid droplets in free fatty acid-treated L02 cells and liver tissues from mice with NAFLD. Inhibition of miR-103-3p reduced the contents of H2O2, TG, ALT, and AST and ROS production while increasing the ATP content. Moreover, the miR-103-3p antagomir alleviated liver tissue lesions in mice with NAFLD. Further studies identified ACOX1, a key enzyme for the oxidation and decomposition of fatty acids, as a direct target of miR-103-3p.

CONCLUSIONS

These findings identified a negative regulatory mechanism between ACOX1 and miR-103-3p that promotes the pathogenesis of NAFLD and suggested that inhibition of miR-103-3p may be a potential treatment strategy for NAFLD.

Exploration of Shared Gene Signatures and Molecular Mechanisms Between Periodontitis and Nonalcoholic Fatty Liver Disease

Background: Periodontitis is associated with periodontal tissue damage and teeth loss. Nonalcoholic fatty liver disease (NAFLD) has an intimate relationship with periodontitis. Nevertheless, interacted mechanisms between them have not been clear. This study was intended for the exploration of shared gene signatures and latent therapeutic targets in periodontitis and NAFLD.

Methods: Microarray datasets of periodontitis and NAFLD were obtained from the Gene Expression Omnibus (GEO) database. The weighted gene co-expression network analysis (WGCNA) was utilized for the acquisition of modules bound up with NAFLD and periodontitis. We used ClueGO to carry out biological analysis on shared genes to search their latent effects in NAFLD and periodontitis. Another cohort composed of differential gene analysis verified the results. The common microRNAs (miRNAs) in NAFLD and periodontitis were acquired in the light of the Human microRNA Disease Database (HMDD). According to miRTarbase, miRDB, and Targetscan databases, latent target genes of miRNAs were forecasted. Finally, the miRNAs–mRNAs network was designed.

Results: Significant modules with periodontitis and NAFLD were obtained via WGCNA. GO enrichment analysis with GlueGo indicated that damaged migration of dendritic cells (DCs) might be a common pathophysiologic feature of NAFLD and periodontitis. In addition, we revealed common genes in NAFLD and periodontitis, including IGK, IGLJ3, IGHM, MME, SELL, ENPP2, VCAN, LCP1, IGHD, FCGR2C, ALOX5AP, IGJ, MMP9, FABP4, IL32, HBB, FMO1, ALPK2, PLA2G7, MNDA, HLA-DRA, and SLC16A7. The results of differential analysis in another cohort were highly accordant with the findings of WGCNA. We established a comorbidity model to explain the underlying mechanism of NAFLD secondary to periodontitis. Finally, the analysis of miRNA pointed out that hsa-mir-125b-5p, hsa-mir-17-5p, and hsa-mir-21-5p might provide potential therapeutic targets.

Conclusion: Our study initially established a comorbidity model to explain the underlying mechanism of NAFLD secondary to periodontitis, found that damaged migration of DCs might be a common pathophysiological feature of NAFLD and periodontitis, and provided potential therapeutic targets.

LncRNA MALAT1 Promotes PPARα/CD36-Mediated Hepatic Lipogenesis in Nonalcoholic Fatty Liver Disease by Modulating miR-206/ARNT Axis

Long non-coding RNAs (lncRNAs) are known to play crucial roles in nonalcoholic fatty liver disease (NAFLD). This research sought to explore mechanisms by which lncRNA MALAT1 regulates the progression of NAFLD. Thus, in order to detect the function of MALAT1 in NAFLD, in vitro and in vivo model of NAFLD were established. Then, fatty acid uptake and triglyceride level were investigated by BODIPY labeled-fatty acid uptake assay and Oil red O staining, respectively. The expressions of MALAT1, miR-206, ARNT, PPARα and CD36 were detected by western blotting and qPCR. Dual luciferase, RIP and ChIP assay were used to validate the relation among MALAT1, miR-206, ARNT and PPARα. The data revealed expression of MALAT1 was up-regulated in vitro and in vivo in NAFLD, and knockdown of MALAT1 suppressed FFA-induced lipid accumulation in hepatocytes. Meanwhile, MALAT1 upregulated the expression of ARNT through binding with miR-206. Moreover, miR-206 inhibitor reversed MALAT1 knockdown effects in decreased lipid accumulation in FFA-treated hepatocytes. Furthermore, ARNT could inhibit the expression of PPARα via binding with PPARα promoter. Knockdown of MALAT1 significantly upregulated the level of PPARα and downregulated the expression of CD36, while PPARα knockdown reversed these phenomena. MALAT1 regulated PPARα/CD36 -mediated hepatic lipid accumulation in NAFLD through regulation of miR-206/ARNT axis. Thus, MALAT1/miR-206/ARNT might serve as a therapeutic target against NAFLD.

Stem Cell-derived Exosomal MicroRNA as Therapy for Vascular Age-related Diseases

Vascular age-related diseases describe a group of age-related chronic diseases that result in a considerable healthcare burden to society. Vascular aging includes structural changes and dysfunctions of endothelial cells (ECs) and smooth muscle cells (SMCs) in blood vessels. Compared with conventional treatment for vascular age-related diseases, stem cell (SC) therapy elicits better anti-aging effects viathe inhibition/delay ECs and SMCs from entering senescence. Exosomal noncoding RNA (ncRNAs) in vascular aging and stem cell-derived exosomal microRNAs (SCEV-miRNAs), especially in mesenchymal stem cells, have an important role in the development of age-related diseases. This review summarizes SCEV-miRNAs of diverse origins that may play a vital role in treating subclinical and clinical stages of vascular age-related disorders. We further explored possible age-related pathways and molecular targets of SCEV-miRNA, which are associated with dysfunctions of ECs and SMCs in the senescent stage. Moreover, the perspectives and difficulties of SCEV-miRNA clinical translation are discussed. This review aims to provide greater understanding of the biology of vascular aging and to identify critical therapeutic targets for SCEV-miRNAs. Though still in its infancy, the potential value of SCEV-miRNAs for vascular age-related diseases is clear.

Interactions between miRNAs and Double-Strand Breaks DNA Repair Genes, Pursuing a Fine-Tuning of Repair

The repair of DNA damage is a crucial process for the correct maintenance of genetic information, thus, allowing the proper functioning of cells. Among the different types of lesions occurring in DNA, double-strand breaks (DSBs) are considered the most harmful type of lesion, which can result in significant loss of genetic information, leading to diseases, such as cancer. DSB repair occurs through two main mechanisms, called non-homologous end joining (NHEJ) and homologous recombination repair (HRR). There is evidence showing that miRNAs play an important role in the regulation of genes acting in NHEJ and HRR mechanisms, either through direct complementary binding to mRNA targets, thus, repressing translation, or by targeting other genes involved in the transcription and activity of DSB repair genes. Therefore, alteration of miRNA expression has an impact on the ability of cells to repair DSBs, which, in turn, affects cancer therapy sensitivity. This latter gives account of the importance of miRNAs as regulators of NHEJ and HRR and places them as a promising target to improve cancer therapy. Here, we review recent reports demonstrating an association between miRNAs and genes involved in NHEJ and HRR. We employed the Web of Science search query TS (“gene official symbol/gene aliases*” AND “miRNA/microRNA/miR-”) and focused on articles published in the last decade, between 2010 and 2021. We also performed a data analysis to represent miRNA–mRNA validated interactions from TarBase v.8, in order to offer an updated overview about the role of miRNAs as regulators of DSB repair.

Synergistic Anti-Ageing through Senescent Cells Specific Reprogramming

In this review, we seek a novel strategy for establishing a rejuvenating microenvironment through senescent cells specific reprogramming. We suggest that partial reprogramming can produce a secretory phenotype that facilitates cellular rejuvenation. This strategy is desired for specific partial reprogramming under control to avoid tumour risk and organ failure due to loss of cellular identity. It also alleviates the chronic inflammatory state associated with ageing and secondary senescence in adjacent cells by improving the senescence-associated secretory phenotype. This manuscript also hopes to explore whether intervening in cellular senescence can improve ageing and promote damage repair, in general, to increase people's healthy lifespan and reduce frailty. Feasible and safe clinical translational protocols are critical in rejuvenation by controlled reprogramming advances. This review discusses the limitations and controversies of these advances' application (while organizing the manuscript according to potential clinical translation schemes) to explore directions and hypotheses that have translational value for subsequent research.

Screening of MicroRNAs with Potential Systemic Effects Released from Goose Fatty Liver

Communication between tissues and organs plays an important role in the maintenance of normal physiological functions as well as the occurrence and development of diseases. Communication molecules act as a bridge for interactions between tissues and organs, playing not only a local role in the tissues and organs where they are secreted but also in exerting systemic effects on the whole body via circulation. In this study, blood microRNA-omics analysis of overfed vs. normally fed (control) Landes geese revealed that the content of each of the 21 microRNAs (miRNAs) in the blood of overfed geese was significantly higher than that in the blood of control geese. These miRNAs may have systematic effects in the development of goose fatty liver as well as being candidate markers for the diagnosis of goose fatty liver. We determined the expression of miR-143, miR-455-5p, miR-222a-5p, miR-184, miR-1662, and miR-129-5p using quantitative PCR in goose fatty liver vs. that in normal liver. The expression of these miRNAs, except miR-129-5p, in goose fatty liver was also significantly higher than that in normal liver (P<0.05), suggesting that these blood miRNAs are released from goose fatty liver. In addition, we found that expression of IGFBP5, the predicted target gene of miR-143, was significantly decreased in goose fatty liver vs. the normal liver (P<0.05), indicating that miR-143 may exert both local and systematic effects by inhibiting the expression of IGFBP5, thus promoting the development of goose fatty liver. In conclusion, we identified several miRNAs, including those we validated (i.e., miR-143, miR-455-5p, miR-222a-5p, miR-184, miR-1662, and miR-129-5p) that may serve as candidate markers in the diagnosis of goose fatty liver as well as local and global regulators contributing to the development of goose fatty liver.

Circulating microRNA profile in humans and mice with congenital GH deficiency

Reduced inflammation, increased insulin sensitivity, and protection against cancer are shared between humans and mice with GH/IGF1 deficiency. Beyond hormone levels, miRNAs are important regulators of metabolic changes associated with healthy aging. We hypothesized that GH deficiency in humans alters the abundance of circulating miRNAs and that a subset of those miRNAs may overlap with those found in GH-deficient mice. In this study, subjects with untreated congenital isolated GH deficiency (IGHD; n = 23) and control subjects matched by age and sex (n = 23) were recruited and serum was collected for miRNA sequencing. Serum miRNAs from young (6 month) and old (22 month) Ames dwarf (df/df) mice with GH deficiency and their WT littermates (n = 5/age/genotype group) were used for comparison. We observed 14 miRNAs regulated with a genotype by age effect and 19 miRNAs regulated with a genotype effect independent of age in serum of IGHD subjects. These regulated miRNAs are known for targeting pathways associated with longevity such as mTOR, insulin signaling, and FoxO. The aging function was overrepresented in IGHD individuals, mediated by hsa-miR-31, hsa-miR-146b, hsa-miR-30e, hsa-miR-100, hsa-miR-181b-2, hsa-miR-195, and hsa-miR-181b-1, which target the FoxO and mTOR pathways. Intriguingly, miR-181b-5p, miR-361-3p, miR-144-3p, and miR-155-5p were commonly regulated in the serum of humans and GH-deficient mice. In vitro assays confirmed target genes for the main up-regulated miRNAs, suggesting miRNAs regulated in IGHD individuals can regulate the expression of age-related genes. These findings indicate that systemic miRNAs regulated in IGHD individuals target pathways involved in aging in both humans and mice.

MiR-665 Regulates Vascular Smooth Muscle Cell Senescence by Interacting With LncRNA GAS5/SDC1

Background: Vascular aging is considered a special risk factor for cardiovascular diseases, and vascular smooth muscle cells (VSMCs) play a major role in aging-related vascular remodeling and in the pathological process of atherosclerosis. Recent research has reported that long non-coding RNA/microRNA (lncRNA/miRNA) is a critical regulator of cellular senescence. However, the role and mechanism of lncRNA GAS5/miR-665 axis in VSMC senescence remain incompletely understood. Methods: Cellular senescence was evaluated using senescence-associated β-gal activity, the NAD+/NADH ratio, and by immunofluorescence staining of γH2AX immunofluorescence. Differentially expressed miRNAs (DEMs) were identified by miRNA microarray assays and subsequently validated by quantitative real-time PCR (qRT-PCR). A dual luciferase reporter assay was conducted to confirm the binding of lncRNA GAS5 and miR-665 as well as miR-665 and syndecan 1 (SDC1). Serum levels of miR-665, lncRNA GAS5, and SDC1 in 93 subjects were detected by qRT-PCR. The participants were subdivided into control, aging, and early vascular aging (EVA) groups, and their brachial-ankle pulse wave velocity (baPWV) was measured. Results: A total of 20 overlapping DEMs were identified in young and old VSMCs via microarray analysis. MiR-665 showed a significant alteration and, therefore, was selected for further analysis. Upregulation of miR-665 was found in aging VSMCs, and downregulation of miR-665 caused an inhibition of VSMCs senescence. Subsequently, the dual luciferase reporter assay determined the binding site of miR-665 with the 3'-UTR of lncRNA GAS5 and SDC1. Increased expression of lncRNA GAS5 expression inhibited the miR-665 level and VSMC senescence. However, as shown in rescue experiment results, either miR-665 overexpression or SDC1 knockdown significantly reversed the effects of lncRNA GAS5 on VSMC senescence. Finally, compared with that of the control group, miR-665 was highly expressed in serum samples in the aging and EVA groups, especially in the EVA groups. On the contrary, serum levels of lncRNA GAS5 and SDC1 were lower in these two groups. Collectively, in the aging and EVA groups, miR-665 expression was negatively correlated with lncRNA GAS5 and SDC1 expression. Conclusion: miR-665 inhibition functions as a vital modulator of VSMC senescence by negatively regulating SDC1, which is achieved by lncRNA GAS5 that sponges miR-665. Our findings may provide a new treatment strategy for aging-related cardiovascular diseases.

miR-1468-3p Promotes Aging-Related Cardiac Fibrosis

Non-coding microRNAs (miRNAs) are powerful regulators of gene expression and critically involved in cardiovascular pathophysiology. The aim of the current study was to identify miRNAs regulating cardiac fibrosis. Cardiac samples of age-matched control subjects and sudden cardiac death (SCD) victims with primary myocardial fibrosis (PMF) were subjected to miRNA profiling. Old SCD victims with PMF and healthy aged human hearts showed increased expression of miR-1468-3p. In vitro studies in human cardiac fibroblasts showed that augmenting miR-1468-3p levels induces collagen deposition and cell metabolic activity and enhances collagen 1, connective tissue growth factor, and periostin expression. In addition, miR-1468-3p promotes cellular senescence with increased senescence-associated β-galactosidase activity and increased expression of p53 and p16. AntimiR-1468-3p antagonized transforming growth factor β1 (TGF-β1)-induced collagen deposition and metabolic activity. Mechanistically, mimic-1468-3p enhanced p38 phosphorylation, while antimiR-1468-3p decreased TGF-β1-induced p38 activation and abolished p38-induced collagen deposition. RNA sequencing analysis, a computational prediction model, and qPCR analysis identified dual-specificity phosphatases (DUSPs) as miR-1468-3p target genes, and regulation of DUSP1 by miR-1468-3p was confirmed with a dual-luciferase reporter assay. In conclusion, miR-1468-3p promotes cardiac fibrosis by enhancing TGF-β1-p38 signaling. Targeting miR-1468-3p in the older population may be of therapeutic interest to reduce cardiac fibrosis.

Peripheral Circulating Exosomal miRNAs Potentially Contribute to the Regulation of Molecular Signaling Networks in Aging

People are living longer than ever. Consequently, they have a greater chance for developing a functional impairment or aging-related disease, such as a neurodegenerative disease, later in life. Thus, it is important to identify and understand mechanisms underlying aging as well as the potential for rejuvenation. Therefore, we used next-generation sequencing to identify differentially expressed microRNAs (miRNAs) in serum exosomes isolated from young (three-month-old) and old (22-month-old) rats and then used bioinformatics to explore candidate genes and aging-related pathways. We identified 2844 mRNAs and 68 miRNAs that were differentially expressed with age. TargetScan revealed that 19 of these miRNAs are predicated to target the 766 mRNAs. Pathways analysis revealed signaling components targeted by these miRNAs: mTOR, AMPK, eNOS, IGF, PTEN, p53, integrins, and growth hormone. In addition, the most frequently predicted target genes regulated by these miRNAs were EIF4EBP1, insulin receptor, PDK1, PTEN, paxillin, and IGF-1 receptor. These signaling pathways and target genes may play critical roles in regulating aging and lifespan, thereby validating our analysis. Understanding the causes of aging and the underlying mechanisms may lead to interventions that could reverse certain aging processes and slow development of aging-related diseases.

Suspended in time: Molecular responses to hibernation also promote longevity

Aging in most animals is an inevitable process that causes or is a result of physiological, biochemical, and molecular changes in the body, and has a strong influence on an organism's lifespan. Although advancement in medicine has allowed humans to live longer, the prevalence of age-associated medical complications is continuously burdening older adults worldwide. Current animal models used in research to study aging have provided novel information that has helped investigators understand the aging process; however, these models are limiting. Aging is a complex process that is regulated at multiple biological levels, and while a single manipulation in these models can provide information on a process, it is not enough to understand the global regulation of aging. Some mammalian hibernators live up to 9.8-times higher than their expected average lifespan, and new research attributes this increase to their ability to hibernate. A common theme amongst these mammalian hibernators is their ability to greatly reduce their metabolic rate to a fraction of their normal rate and initiate cytoprotective responses that enable their survival. Metabolic rate depression is strictly regulated at different biological levels in order to enable the animal to not only survive, but to also do so by relying mainly on their limited internal fuels. As such, understanding both the global and specific regulatory mechanisms used to promote survival during hibernation could, in theory, allow investigators to have a better understanding of the aging process. This can also allow pharmaceutical industries to find therapeutics that could delay or reverse age-associated medical complications and promote healthy aging and longevity in humans.

Metformin Reduces the Senescence of Renal Tubular Epithelial Cells in Diabetic Nephropathy via the MBNL1/miR-130a-3p/STAT3 Pathway

Senescence of renal tubular epithelial cells plays an important role in diabetic nephropathy, but the mechanism is unknown. Metformin may alleviate diabetic nephropathy by reducing this senescence. This study is aimed at clarifying the effects and mechanism of metformin on the senescence of renal tubular epithelial cells in diabetic nephropathy. We found that metformin reduced the expression of senescence-associated gene P21 in high-glucose-induced (30 mmol/L) renal tubular epithelial cells and decreased the β-galactosidase positive staining rate (decreased 16%, p < 0.01). Metformin was able to reduce senescence by upregulating the expression of RNA-binding protein MBNL1 and miR-130a-3p and reducing STAT3 expression. MBNL1 prolonged the half-life of miR-130a-3p, and miR-130a-3p could negatively regulate STAT3 by binding to its mRNA 3′UTR. In db/db diabetic mice, we found an enhanced senescence level combined with low expression of MBNL1 and miR-130a-3p and high expression of STAT3 compared with db/m control mice during nephropathy development. Meanwhile, metformin (200 mg/kg/day) could increase the expression of MBNL1 and miR-130a-3p and decreased STAT3 expression, thus reducing this senescence in db/db mice. Our results suggest that metformin reduces the senescence of renal tubular epithelial cells in diabetic nephropathy via the MBNL1/miR-130a-3p/STAT3 pathway, which provided new ideas for the therapy of this disease.

LncRNA-H19 promotes hepatic lipogenesis by directly regulating miR-130a/PPARγ axis in non-alcoholic fatty liver disease

Background: As one of the most common liver disorders worldwide, non-alcoholic fatty liver disease (NAFLD) begins with the abnormal accumulation of triglyceride (TG) in the liver. Long non-coding RNA-H19 was reported to modulate hepatic metabolic homeostasis in NAFLD. However, its molecular mechanism of NAFLD was not fully clear.Methods:In vitro and in vivo models of NAFLD were established by free fatty acid (FFA) treatment of hepatocytes and high-fat feeding mice, respectively. Hematoxylin and Eosin (H&E) and Oil-Red O staining detected liver tissue morphology and lipid accumulation. Immunohistochemistry (IHC) staining examined peroxisome proliferator-activated receptor γ (PPARγ) level in liver tissues. ELISA assay assessed TG secretion. Luciferase assay and RNA pull down were used to validate regulatory mechanism among H19, miR-130a and PPARγ. The gene expression in hepatocytes and liver tissues was detected by quantitative real-time PCR (qRT-PCR) and Western blotting.Results: H19 and PPARγ were up-regulated, while miR-130a was down-regulated in NAFLD mouse and cellular model. H&E and Oil-Red O staining indicated an increased lipid accumulation. Knockdown of H19 inhibited steatosis and TG secretion in FFA-induced hepatocytes. H19 could bind to miR-130a, and miR-130a could directly inhibit PPARγ expression. Meanwhile, miR-130a inhibited lipid accumulation by down-regulating NAFLD-related genes PPARγ, SREBP1, SCD1, ACC1 and FASN. Overexpression of miR-130a and PPARγ antagonist GW9662 inhibited lipogenesis and TG secretion, and PPARγ agonist GW1929 reversed this change induced by miR-130a up-regulation.Conclusion: Knockdown of H19 alleviated hepatic lipogenesis via directly regulating miR-130a/PPARγ axis, which is a novel mechanistic role of H19 in the regulation of NAFLD.

Effects of high-fat diet on growth performance, lipid accumulation and lipid metabolism-related MicroRNA/gene expression in the liver of grass carp (Ctenopharyngodon idella)

An 8 week experiment was conducted to evaluate the effects of dietary fat on growth and on the accumulation of lipids and the expression of lipid metabolism-related microRNAs (miRNAs) and genes in grass carp (Ctenopharyngodon idella). Two diets (normal fat diet (NFD), 60 g/kg lipid content; high fat diet (HFD), 160 g/kg lipid content) were fed to triplicate groups of 35 fish [initial weight of (40.0 ± 0.5) g]. The results showed that increased dietary fat did not lead to significant differences in the feed conversion rate (FCR) and specific growth rate (SGR) (P > .05), but the HFD significantly increased the hepatosomatic index (HSI) (P < .05). The serum high density lipoprotein-cholesterol (HDLC) level was significantly increased in the HFD group (P < .05). Oil Red O staining showed that both the size and amounts of lipid droplets in the liver of fish fed a diet with 2 g/kg lipid content increased significantly. In the liver of fish fed with 160 g/kg dietary fat, the expression of mir-33a, mir-30, mir-122 and mir-16 significantly decreased (P < .05). In contrast, the expression of sterol regulatory element-binding transcription factor 1 (SREBP1), peroxisome proliferator-activated receptor gamma (PPARγ), liver X receptor alpha (LXRα) and ATP-binding cassette transporter A1 (ABCA1) significantly increased (P < .05). In conclusion, 2 g/kg dietary fat did not influence growth but altered the expression of miRNAs and genes related to lipid metabolism in the liver of grass carp, which caused severe lipid deposition.

Multi-level remodeling of transcriptional landscapes in aging and longevity

In multi-cellular organisms, the control of gene expression is key not only for development, but also for adult cellular homeostasis, and gene expression has been observed to be deregulated with aging. In this review, we discuss the current knowledge on the transcriptional alterations that have been described to occur with age in metazoans. First, we discuss age-related transcriptional changes in protein-coding genes, the expected functional impact of such changes, and how known pro-longevity interventions impact these changes. Second, we discuss the changes and impact of emerging aspects of transcription in aging, including age-related changes in splicing, lncRNAs and circRNAs. Third, we discuss the changes and potential impact of transcription of transposable elements with aging. Fourth, we highlight small ncRNAs and their potential impact on the regulation of aging phenotypes. Understanding the aging transcriptome will be key to identify important regulatory targets, and ultimately slow-down or reverse aging and extend healthy lifespan in humans.

Multi-level remodeling of transcriptional landscapes in aging and longevity

In multi-cellular organisms, the control of gene expression is key not only for development, but also for adult cellular homeostasis, and gene expression has been observed to be deregulated with aging. In this review, we discuss the current knowledge on the transcriptional alterations that have been described to occur with age in metazoans. First, we discuss age-related transcriptional changes in protein-coding genes, the expected functional impact of such changes, and how known pro-longevity interventions impact these changes. Second, we discuss the changes and impact of emerging aspects of transcription in aging, including age-related changes in splicing, lncRNAs and circRNAs. Third, we discuss the changes and potential impact of transcription of transposable elements with aging. Fourth, we highlight small ncRNAs and their potential impact on the regulation of aging phenotypes. Understanding the aging transcriptome will be key to identify important regulatory targets, and ultimately slow-down or reverse aging and extend healthy lifespan in humans. [BMB Reports 2019; 52(1): 86-108].

Effect of young exosomes injected in aged mice

INTRODUCTION

Exosomes, nanosized extracellular vesicles, are known to circulate through the blood stream to transfer molecular signals from tissue to tissue.

METHODS

To determine whether exosomes affect aging in animals, we primarily identified the changes in exosomal miRNA contents during the aging process. In exosomes from 12-month-old mice, mmu-miR-126-5p and mmu-miR-466c-5p levels were decreased and mmu-miR-184-3p and mmu-miR-200b-5p levels were increased significantly compared with those of 3-month-old mice. Their levels in exosomes were partially correlated with those in tissues: levels of only mmu-miR-126-5p and mmu-miR-466c-5p in lungs and/or liver were decreased, but those of mmu-miR-184-3p and mmu-miR-200b-5p in tissues did not coincide with those of exosomes.

RESULTS AND DISCUSSION

In the aged tissues injected with young exosomes isolated from serum, mmu-miR-126b-5p levels were reversed in the lungs and liver. Expression changes in aging-associated molecules in young exosome-injected mice were obvious: p16Ink4A, MTOR, and IGF1R were significantly downregulated in the lungs and/or liver of old mice. In addition, telomerase-related genes such as Men1, Mre11a, Tep1, Terf2, Tert, and Tnks were significantly upregulated in the liver of old mice after injection of young exosomes.

CONCLUSION

These results indicate that exosomes from young mice could reverse the expression pattern of aging-associated molecules in aged mice. Eventually, exosomes may be used as a novel approach for the treatment and diagnosis of aging animals.

Identification of novel genes in aging osteoblasts using next-generation sequencing and bioinformatics

During the aging process, impaired osteoblastic function is one key factor of imbalanced bone formation and age-related bone loss. The aim of this study is to explore the differentially expressed genes in normal and aged osteoblasts and to identify genes potentially involved in age-related alteration in bone physiology. Based on next generation sequencing and bioinformatics analysis, 12 differentially expressed microRNAs and 22 differentially expressed genes were identified. Up-regulation of miR-204-5p was validated in an array of osteoporotic hip fracture in the Gene Expression Omnibus database (GSE74209). The putative targets for miR-204-5p were Kruppel-like factor 7 (KLF7) and SRY-box 11 (SOX11). Ingenuity Pathway Analysis identified SOX11, involved in osteoarthritis pathway and differentiation of osteoblasts, together with miR-204-5p, a potential upstream regulator, suggesting the critical role of miR-204-5p-SOX11 regulation in the aging process of human bones. In addition, as semaphorin 3A (SEMA3A) and ephrin type-A receptor 5 (EPHA5) were involved in nervous system related biological functions, we postulated a potential linkage between SEMA3A, EPHA5 and development of neurogenic heterotopic ossification. Our findings implicate new candidate genes in the diagnosis of geriatric musculoskeletal disorders, and provide novel insights that may contribute to the elaboration of new biomarkers for neurogenic heterotopic ossification.

Cellular senescence and liver disease: Mechanisms and therapeutic strategies

Cellular senescence is a fundamental cell fate caused by several cellular injuries which results in irreversible cell cycle arrest yet remaining metabolically active across all species. Cellular senescence not only can prevent tumor occurrence by inhibiting the proliferation of injured cells, but also can affect the surrounding cells through the senescence-associated secretory phenotype (SASP). Attractively, accumulating evidence shows that cellular senescence is closely related to various liver diseases. Therapeutic opportunities based on targeting senescent cells and the SASP are considered to be potential strategy for liver diseases. However, although research on cell senescence has attracted widespread attention, the overview on detailed mechanism and biological function of cell senescence in liver disease is still largely unknown. The present review summarizes the specific role of cell senescence in various liver diseases, and updates the molecular mechanisms underlying cell senescence. Moreover, the review also explores new strategies for prevention and treatment of liver disease through promoting senescence or counteracting excessive pathological senescence.

Ezetimibe alleviates non-alcoholic fatty liver disease through the miR-16 inhibiting mTOR/p70S6K1 pathway

Emerging studies have indicated the role of ezetimibe, miR-16 and mTOR signaling in non-alcoholic fatty liver disease (NAFLD).