miR-34a/SIRT1/p53 is suppressed by ursodeoxycholic acid in the rat liver and activated by disease severity in human non-alcoholic fatty liver disease

Lycium barbarum polysaccharide alleviates H2O2-induced premature senescence by downregulating miRNA-34a-5p in ARPE-19 cells

The premature senescence of retinal pigment epithelium (RPE) plays a significant role in the development of age-related macular degeneration. This study aimed to investigate the potential protective effect of Lycium barbarum polysaccharide (LBP) against H2O2-induced premature senescence and to elucidate the underlying mechanisms. The ARPE-19 cell line was subjected to H2O2 exposure to create a model of premature senescence. The modulation of microRNA-34a-5p expression was accomplished using antagomir and agomir, as assessed by quantitative real-time polymerase chain reaction. The senescence model was successfully established by treating cells with 200 μM H2O2 for 2 hours daily over a span of three consecutive days. This oxidative stress resulted in a notable increase in the proportion of senescence-associated beta-galactosidase-positive cells, reaching 33.5%, without significant alterations in cell viability or apoptosis. In the ARPE-19 cells undergoing premature senescence, there was a marked increase in reactive oxygen species (ROS) production and malondialdehyde levels, coupled with a significant decrease in the activity of total superoxide dismutase, glutathione peroxidase, and catalase. Additionally, microRNA-34a-5p was found to be overexpressed in these cells. Treatment with LBP alleviated H2O2-induced premature senescence, diminished the overexpression of microRNA-34a-5p, and suppressed ROS production. Moreover, the incubation with ago-34a reversed the protective effect of LBP in ARPE-19 cells. In conclusion, the overexpression of microRNA-34a-5p contributes to the H2O2-induced premature senescence of ARPE-19 cells. LBP appears to mitigate this premature senescence, at least in part, by downregulating microRNA-34a-5p expression and reducing oxidative stress.

Regulation of Apoptotic Pathways by MicroRNAs: A Therapeutic Strategy for Alzheimer's Disease

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder marked by a gradual decline in memory and cognitive functions. It is characterized by the presence of senile plaques, neurofibrillary tangles, and neuronal degeneration, affecting a significant portion of the human population. A key feature of various nervous system disorders, including AD, is extensive cellular death caused by apoptosis, which affects not only neurons but also glial cells. While apoptosis plays a vital role in eliminating certain cells and supporting normal development, alterations or disruptions in apoptotic pathways can lead to harmful neurodegenerative conditions such as AD. Thus, targeting apoptosis presents a promising therapeutic approach for these diseases. MicroRNAs (miRNAs), a class of non-coding RNA, play diverse roles in cellular functions, including proliferation, gene expression regulation, programmed cell death, intercellular communication, and angiogenesis. By modulating regulatory genes, miRNAs can influence apoptosis, either promoting or inhibiting it. Aberrant expression of miRNAs can impact multiple apoptotic pathways, potentially driving the progression of AD and related health issues. This review summarizes recent research on miRNAs and their dual role in exacerbating or protecting against neural cell damage in AD by altering apoptotic pathways. The regulation of apoptosis by miRNAs offers a prospective therapeutic strategy for Alzheimer's disease.

miR-34a-5p/MARCHF8/ADAM10 axis in the regulation of vascular endothelial cell dysfunction and senescence

Vascular aging is a key driver of age-related cardiovascular and metabolic diseases, with endothelial dysfunction and senescence as a central mechanism. In our recent study, we observed elevated ADAM10 protein levels in senescent endothelial cells, which worsened endothelial dysfunction and senescence. However, the regulatory mechanisms controlling ADAM10 expression are poorly understood. In this study, we show that ADAM10 undergoes post-transcriptional modification in senescent human umbilical vein endothelial cells (HUVECs), with the E3 ubiquitin ligase MARCHF8 predicted to facilitate its ubiquitination-dependent degradation. We also found that MARCHF8 expression was significantly reduced in senescent HUVECs. Knockdown of MARCHF8 in young HUVECs induced endothelial senescence and impaired key endothelial functions, including migration, proliferation, angiogenesis, and nitric oxide production. Conversely, overexpression of MARCHF8 in senescent HUVECs ameliorated senescence-associated dysfunctions. RNA sequencing analysis revealed that MARCHF8 knockdown disrupted pathways linked to cell senescence and atherosclerosis. In vivo, MARCHF8 overexpression in high-fat diet-fed apoE-/- mice reduced plasma interleukin-6 levels and attenuated atherosclerosis progression. Additionally, miR-34a-5p upregulation in senescence inhibited MARCHF8 expression, compromising its protective effects in delaying endothelial senescence. Collectively, these findings reveal a novel miR-34a-5p/MARCHF8/ADAM10 axis in vascular endothelial senescence, positioning MARCHF8 as a potential biomarker and therapeutic target for vascular aging and related diseases.

Advancing precision medicine in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease (NAFLD), has become a pressing global health concern. The complexity of MASLD and the lack of universally effective treatments expose the limitations of current interventions, which focus mainly on lifestyle modifications. Here, we explore the multilayered nature of MASLD, emphasizing its pathophysiology in shaping future medical and lifestyle interventions from a personalized medicine perspective, based on individual molecular profiles. Additionally, we address the limitations of current animal models in reflecting human metabolic syndrome and sex-specific differences. We argue that a holistic approach, integrating social determinants of health, patient preferences, and adherence patterns, is essential for advancing MASLD management effectively.

A class of MicroRNAs as diagnostic biomarkers and therapeutic strategies in non-alcoholic fatty liver disease: A review

MicroRNAs (miRNAs), small and noncoding RNAs that regulate gene expression through hybridization to messenger RNA, play a crucial role in the prevention or progression of non-alcoholic fatty liver disease (NAFLD). There is an urgent demand for the improvement of diagnostic tools and effective pharmacotherapies for the treatment of NAFLD, which can advance to cirrhosis and liver cancer. MiRNAs act as regulatory factors and noninvasive diagnostic agents for NAFLD, enabling the staging of the disorder, prognosis, and identification of pharmaco-therapeutic targets. NAFLD causes alterations in the expression patterns of hepatocyte miRNAs, with some specific miRNAs related to the upgrade from NAFLD to non-alcoholic steatohepatitis (NASH). These miRNAs can activate certain signaling cascade and exacerbate or improve NAFLD, additionally, act as hepatocellular signals or second messengers that transmit information between the liver and other systems. This study provides a comprehensive review of the most important miRNAs and their involvement in the pathophysiology and cellular signaling pathways related to NAFLD.

Lipotoxicity-driven metabolic dysfunction-associated steatotic liver disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses a spectrum of liver lesions, ranging from simple steatosis to metabolic dysfunction-associated steatohepatitis (MASH), that may further progress to cirrhosis. MASLD is estimated to affect more than one third of the general population and it represents a risk factor for end-stage liver failure and liver cancer, substantially contributing to liver-related morbidity and mortality. Although the pathogenesis of MASLD is incompletely understood, it is known to consist of a multifactorial process influenced by extrinsic and intrinsic factors such as metabolic, environmental and demographic features, gut microbiota and genetics. Dysregulation of both extracellular and intracellular lipid composition is known to promote the generation of toxic lipid species, thereby triggering lipotoxicity and cellular stress. These events ultimately lead to the activation of distinct cell death pathways, resulting in inflammation, fibrogenesis and, eventually, carcinogenesis. In this manuscript, we provide a comprehensive review of the role of lipotoxicity during MASLD pathogenesis, discussing the most relevant lipid species and related molecular mechanisms, summarizing the cell type-specific effects and highlighting the most promising putative therapeutic strategies for modulating lipotoxicity and lipid metabolism in MASLD.

Hepatic miR-363 promotes nonalcoholic fatty liver disease by suppressing INSIG1

Nonalcoholic fatty liver disease (NAFLD) constitutes one of major worldwide health problem which typically progressively results in nonalcoholic steatohepatitis (NASH) and eventually cirrhosis and liver cancer. Liver-specific deletion of INSIG1 promotes SREBP1 nuclear translocation to activate downstream lipogenic genes expression, leading to lipid accumulation. However, the underlying pathogenesis of NAFLD, and particularly involved in miRNA participation are still to be thoroughly explored. Here, we found that miR-363-3p was significantly overexpressed in high-fat, high-cholesterol (HFHC) diet mice liver tissue and fatty acid-induced steatosis cells. miR-363-3p directly targets INSIG1 to inhibit its expression, thereby facilitating the cleavage of SREBP and nuclear translocation to activate subsequent transcription of lipogenic genes in vitro and in vivo. In addition, we identified apigenin, a natural flavonoid compound, inhibited miR-363-3p expression to up-regulate INSIG1 and suppress nuclear translocation of SREBP1, thereby down-regulated lipogenic genes expression in steatosis cells and HFHC diet mice liver tissues. Taken together, our results demonstrated that miR-363-3p as a key regulator of hepatic lipid homeostasis targeted INSIG1, and apigenin alleviated NAFLD through the miR-363-3p/INSIG1/SREBP1 pathway. This indicates that reduction of miR-363-3p levels as a possible treatment of hepatic steatosis and provides a potential new therapeutic strategy for targeting miRNA to ameliorate NAFLD.

Inhibition of SIRT1 relieves hepatocarcinogenesis via alleviating autophagy and inflammation

Imbalanced Sirtuin 1 (SIRT1) levels may lead to liver diseases through abnormal regulation of autophagy, but the roles of SIRT1-regulated autophagy in hepatocellular carcinoma are still controversial. In this study, we found that SIRT1 mRNA and protein levels were upregulated in hepatocellular carcinoma, and high SIRT1 expression hinted an advanced stage and a poor prognosis. The differentially expressed proteins were significantly elevated in autophagy, cellular response to stress, and immune signaling pathways. In a thioacetamide-induced hepatocellular carcinoma mouse model, we found that SIRT1 expression was highly increased with increased autophagy and excessive macrophage inflammatory response. Next, we established a Hepa 1-6 cells and macrophage co-culture system in vitro to model the alteration of tumor microenvironment, and found that the medium from CCl4-treated or SIRT1-overexpressing Hepa 1-6 cells triggered the polarization of macrophage M1, and the culture medium derived from M1 macrophage promoted Hepa 1-6 cells growth and intracellular oxidative stress. The progression of liver fibrosis in the CCl4-induced liver fibrosis mouse model showed that inhibition of SIRT1 alleviated inflammatory response and ameliorated liver fibrosis. These findings suggest that SIRT1-regulated autophagy and inflammation are oncogenic in hepatocarcinogenesis.

Sirtuin 1 in regulating the p53/glutathione peroxidase 4/gasdermin D axis in acute liver failure

In this editorial, we comment on the article by Zhou et al. The study reveals the connection between ferroptosis and pyroptosis and the effect of silent information regulator sirtuin 1 (SIRT1) activation in acute liver failure (ALF). ALF is characterized by a sudden and severe liver injury resulting in significant hepatocyte damage, often posing a high risk of mortality. The predominant form of hepatic cell death in ALF involves apoptosis, ferroptosis, autophagy, pyroptosis, and necroptosis. Glutathione peroxidase 4 (GPX4) inhibition sensitizes the cell to ferroptosis and triggers cell death, while Gasdermin D (GSDMD) is a mediator of pyroptosis. The study showed that ferroptosis and pyroptosis in ALF are regulated by blocking the p53/GPX4/GSDMD pathway, bridging the gap between the two processes. The inhibition of p53 elevates the levels of GPX4, reducing the levels of inflammatory and liver injury markers, ferroptotic events, and GSDMD-N protein levels. Reduced p53 expression and increased GPX4 on deletion of GSDMD indicated ferroptosis and pyroptosis interaction. SIRT1 is a NAD-dependent deacetylase, and its activation attenuates liver injury and inflammation, accompanied by reduced ferroptosis and pyroptosis-related proteins in ALF. SIRT1 activation also inhibits the p53/GPX4/GSDMD axis by inducing p53 acetylation, attenuating LPS/D-GalN-induced ALF.

FABP4 deficiency ameliorates alcoholic steatohepatitis in mice via inhibition of p53 signaling pathway

Fatty acid-binding protein 4 (FABP4) plays an essential role in metabolism and inflammation. However, the role of FABP4 in alcoholic steatohepatitis (ASH) remains unclear. This study aimed to investigate the function and underlying mechanisms of FABP4 in the progression of ASH. We first obtained alcoholic hepatitis (AH) datasets from the National Center for Biotechnology Information-Gene Expression Omnibus database and conducted bioinformatics analysis to identify critical genes in the FABP family. We then established ASH models of the wild-type (WT) and Fabp4-deficient (Fabp4-/-) mice to investigate the role of FABP4 in ASH. Additionally, we performed transcriptional profiling of mouse liver tissue and analyzed the results using integrative bioinformatics. The FABP4-associated signaling pathway was further verified. FABP4 was upregulated in two AH datasets and was thus identified as a critical biomarker for AH. FABP4 expression was higher in the liver tissues of patients with alcoholic liver disease and ASH mice than in the corresponding control samples. Furthermore, the Fabp4-/- ASH mice showed reduced hepatic lipid deposition and inflammation compared with the WT ASH mice. Mechanistically, Fabp4 may be involved in regulating the p53 and sirtuin-1 signaling pathways, subsequently affecting lipid metabolism and macrophage polarization in the liver of ASH mice. Our results demonstrate that Fabp4 is involved in the progression of ASH and that Fabp4 deficiency may ameliorate ASH. Therefore, FABP4 may be a potential therapeutic target for ASH treatment.

The Loss of an Orphan Nuclear Receptor NR2E3 Augments Wnt/β-catenin Signaling via Epigenetic Dysregulation that Enhances Sp1-β catenin-p300 Interactions in Hepatocellular Carcinoma

The orphan nuclear receptor NR2E3 (Nuclear receptor subfamily 2 group E, Member 3) is an epigenetic player that modulates chromatin accessibility to activate p53 during liver injury. Nonetheless, a precise tumor suppressive and epigenetic role of NR2E3 in hepatocellular carcinoma (HCC) development remains unclear. HCC patients expressing low NR2E3 exhibit unfavorable clinical outcomes, aligning with heightened activation of the Wnt/β-catenin signaling pathway. The murine HCC models utilizing NR2E3 knockout mice consistently exhibits accelerated liver tumor formation accompanied by enhanced activation of Wnt/β-catenin signaling pathway and inactivation of p53 signaling. At cellular level, the loss of NR2E3 increases the acquisition of aggressive cancer cell phenotype and tumorigenicity and upregulates key genes in the WNT/β-catenin pathway with increased chromatin accessibility. This event is mediated through increased formation of active transcription complex involving Sp1, β-catenin, and p300, a histone acetyltransferase, on the promoters of target genes. These findings demonstrate that the loss of NR2E3 activates Wnt/β-catenin signaling at cellular and organism levels and this dysregulation is associated with aggressive HCC development and poor clinical outcomes. In summary, NR2E3 is a novel tumor suppressor with a significant prognostic value, maintaining epigenetic homeostasis to suppress the Wnt/β-catenin signaling pathway that promotes HCC development.

Excessive fatty acids activate PRMT5/MDM2/Drosha pathway to regulate miRNA biogenesis and lipid metabolism

BACKGROUND

Excessive fatty acids in the liver lead to the accumulation of lipotoxic lipids and then cellular stress to further evoke the related disease, like non-alcoholic fatty liver disease (NAFLD). As reported, fatty acid stimulation can cause some specific miRNA dysregulation, which caused us to investigate the relationship between miRNA biogenesis and fatty acid overload.

METHODS

Gene expression omnibus (GEO) dataset analysis, miRNA-seq, miRNA cleavage assay, RT-qPCR, western blotting, immunofluorescence and co-immunoprecipitation (co-IP) were used to reveal the change of miRNAs under pathological status and explore the relevant mechanism. High fat, high fructose, high cholesterol (HFHFrHC) diet-fed mice transfected with AAV2/8-shDrosha or AAV2/8-shPRMT5 were established to investigate the in vivo effects of Drosha or PRMT5 on NAFLD phenotype.

RESULTS

We discovered that the cleavage of miRNAs was inhibited by analysing miRNA contents and detecting some representative pri-miRNAs in multiple mouse and cell models, which was further verified by the reduction of the Microprocessor activity in the presence of palmitic acid (PA). In vitro, PA could induce Drosha, the core RNase III in the Microprocessor complex, degrading through the proteasome-mediated pathway, while in vivo, knockdown of Drosha significantly promoted NAFLD to develop to a more serious stage. Mechanistically, our results demonstrated that PA can increase the methyltransferase activity of PRMT5 to degrade Drosha through MDM2, a ubiquitin E3 ligase for Drosha. The above results indicated that PRMT5 may be a critical regulator in lipid metabolism during NAFLD, which was confirmed by the knocking down of PRMT5 improved aberrant lipid metabolism in vitro and in vivo.

CONCLUSIONS

We first demonstrated the relationship between miRNA dosage and NAFLD and proved that PA can activate the PRMT5-MDM2-Drosha signalling pathway to regulate miRNA biogenesis.

Resveratrol attenuates against high-fat-diet-promoted non-alcoholic fatty liver disease in rats mainly by targeting the miR-34a/SIRT1 axis

This study evaluated if miR-34a/SIRT1 signalling mediates the anti-hepatosteatotic effect of resveratrol (RSV) in high-fat-diet (HFD)-fed rats. Rats were divided into seven groups (n = 6/each) as control, control + miR-34a agomir negative control, HFD, HFD + miR-34a, HFD + RSV, HFD + RSV + Ex-527 (a SIRT1 inhibitor), and HFD + RSV + miR-34a agomir. After 8 weeks, RSV suppressed dyslipidemia, lowered fasting glucose and insulin levels, improved insulin sensitivity, and prevented hepatic lipid accumulation. These effects were associated with hepatic downregulation of SREBP1 and SREBP2, upregulation of PPARα, and acetylation of Nrf2 (activation) and NF-κβ p65 (inhibition). Also, RSV reduced the transcription of miR-34a and increased the nuclear localisation of SIRT1 in the livers, muscles, and adipose tissues of HFD-fed rats. All these effects were prevented by EX-527 and miR-34a agmir. In conclusion, RSV prevents HFD-induced insulin resistance and hepatic steatosis by suppressing miR-34a-induced activation of SIRT1.

SIRT1: Harnessing multiple pathways to hinder NAFLD

Non-alcoholic fatty liver disease (NAFLD) encompasses hepatic steatosis, non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma. It is the primary cause of chronic liver disorders, with a high prevalence but no approved treatment. Therefore, it is indispensable to find a trustworthy therapy for NAFLD. Recently, mounting evidence illustrates that Sirtuin 1 (SIRT1) is strongly associated with NAFLD. SIRT1 activation or overexpression attenuate NAFLD, while SIRT1 deficiency aggravates NAFLD. Besides, an array of therapeutic agents, including natural compounds, synthetic compounds, traditional Chinese medicine formula, and stem cell transplantation, alleviates NALFD via SIRT1 activation or upregulation. Mechanically, SIRT1 alleviates NAFLD by reestablishing autophagy, enhancing mitochondrial function, suppressing oxidative stress, and coordinating lipid metabolism, as well as reducing hepatocyte apoptosis and inflammation. In this review, we introduced the structure and function of SIRT1 briefly, and summarized the effect of SIRT1 on NAFLD and its mechanism, along with the application of SIRT1 agonists in treating NAFLD.

Renal Tissue-Derived Exosomal miRNA-34a in Diabetic Nephropathy Induces Renal Tubular Cell Fibrosis by Promoting the Polarization of M1 Macrophages

Background

Diabetic nephropathy (DN) is the leading cause of chronic kidney disease, and the activation and infiltration of phagocytes are critical steps of DN. This study aimed to explore the mechanism of exosomes in macrophages and diabetes nephropathy and the role of miRNA-34a, which might provide a new path for treating DN.

Materials and Methods

The DN model was established, and the success of the model establishment was confirmed by detecting general indicators, HE staining, and immunohistochemistry. Electron microscopy and NanoSight Tracking Analysis (NTA) were used to see the morphology and size of exosomes. MiRNA-34a inhibitor, miRNA-34a mimics, pc-PPARGC1A, and controls were transfected in macrophages with or without kidney exosomal. A dual-luciferase reporter gene experiment verifies the targeting relationship between miRNA-34a and PPARGC1A. After exosomal culture, macrophages are co-cultured with normal renal tubular cells to detect renal tubular cell fibrosis. Q-PCR and western blot were undertaken to detect related RNA and proteins.

Results

An animal model of diabetic nephropathy was successfully constructed. Macrophages could phagocytose exosomes. After ingesting model exosomes, M1 macrophages were activated, while M2 macrophages were weakened, indicating the model mice's kidney exosomes caused the polarization. MiRNA-34a inhibitor increased PPARGC1A expression. MiRNA-34a expressed higher in diabetic nephropathy Model-Exo. MiRNA-34a negatively regulated PPARGC1A. PPARGC1A rescued macrophage polarization and renal tubular cell fibrosis.

Conclusion

Exosomal miRNA-34a of tubular epithelial cells promoted M1 macrophage activation in diabetic nephropathy via negatively regulating PPARGC1A expression, which may provide a new direction for further exploration of DN treatment.

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

Understanding the role of ursodeoxycholic acid and gut microbiome in non-alcoholic fatty liver disease: current evidence and perspectives

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, resulting in a huge medical burden worldwide. Accumulating evidence suggests that the gut microbiome and bile acids play pivotal roles during the development of NAFLD. Patients with NAFLD exhibit unique signatures of the intestinal microbiome marked by the priority of Gram-negative bacteria, decreased ratio of Firmicutes/Bacteroidetes (F/B), and increased Prevotella and Lachnospiraceae. The intestinal microbiota is involved in the metabolism of bile acids. Ursodeoxycholic acid (UDCA) is a key determinant in maintaining the dynamic communication between the host and gut microbiota. It generally shows surprising therapeutic potential in NAFLD with several mechanisms, such as improving cellular autophagy, apoptosis, and mitochondrial functions. This action is based on its direct or indirect effect, targeting the farnesoid X receptor (FXR) and various other nuclear receptors. This review aims to discuss the current studies on the involvement of the microbiome-UDCA interface in NAFLD therapy and provide prospective insights into future preventative and therapeutic approaches for NAFLD.

Integrated traditional Chinese and Western medicine in the prevention and treatment of non-alcoholic fatty liver disease: future directions and strategies

Traditional Chinese medicine (TCM) has been widely used for several centuries for metabolic diseases, including non-alcoholic fatty liver disease (NAFLD). At present, NAFLD has become the most prevalent form of chronic liver disease worldwide and can progress to non-alcoholic steatohepatitis (NASH), cirrhosis, and even hepatocellular carcinoma. However, there is still a lack of effective treatment strategies in Western medicine. The development of NAFLD is driven by multiple mechanisms, including genetic factors, insulin resistance, lipotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, inflammation, gut microbiota dysbiosis, and adipose tissue dysfunction. Currently, certain drugs, including insulin sensitizers, statins, vitamin E, ursodeoxycholic acid and betaine, are proven to be beneficial for the clinical treatment of NAFLD. Due to its complex pathogenesis, personalized medicine that integrates various mechanisms may provide better benefits to patients with NAFLD. The holistic view and syndrome differentiation of TCM have advantages in treating NAFLD, which are similar to the principles of personalized medicine. In TCM, NAFLD is primarily classified into five types based on clinical experience. It is located in the liver and is closely related to spleen and kidney functions. However, due to the multi-component characteristics of traditional Chinese medicine, its application in the treatment of NAFLD has been considerably limited. In this review, we summarize the advances in the pathogenesis and treatment of NAFLD, drawn from both the Western medicine and TCM perspectives. We highlight that Chinese and Western medicine have complementary advantages and should receive increased attention in the prevention and treatment of NAFLD.

Chaihu Shugan powder influences nonalcoholic fatty liver disease in rats in remodeling microRNAome and decreasing fatty acid synthesis

ETHNOPHARMACOLOGICAL RELEVANCE

Chaihu Shugan powder (CSP) plays an important role in the prevention and treatment of nonalcoholic fatty liver disease (NAFLD) through a variety of biological mechanisms. However, whether the mechanism involves microRNA (miRNA) regulation remains unknown.

AIM OF THE STUDY

To investigate the effects of CSP on the miRNA expression profile of rats with NAFLD induced by high-fat diet (HFD), and to explore the mechanism of CSP in the treatment of NAFLD.

METHODS

NAFLD rat models were established by an 8-week HFD. The therapeutic effects of CSP on NAFLD were evaluated by physiological, biochemical and pathological analysis and hepatic surface microcirculation perfusion test. MicroRNA sequencing was used to study the effect of CSP on the miRNA expression profile of NAFLD rats, and the target genes of differentially expressed (DE) miRNAs were predicted for further function enrichment analysis. Next, targets of CSP and NAFLD were collected by a network pharmacological approach, and Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis were performed for the common target genes of CSP, NAFLD and DE miRNAs, and the expression levels of key genes and proteins were verified by quantitative Real-time PCR and Western blot. Finally, a network among formula-herb-compound-miRNA-target-biological processes-disease was established to explained the complex regulation mechanism of CSP on NAFLD.

RESULTS

The results showed that CSP significantly improved liver lipid accumulation, serum lipid and transaminase levels and liver surface microcirculation disturbance in HFD-induced NAFLD rats. The intervention of CSP reversed the high expression of 15 miRNAs in liver tissues induced by HFD, including miR-34a-5p, miR-146a-5p, miR-20b-5p and miR-142-3p. The results of pathway and functional enrichment analysis showed that, CSP might play an anti-NAFLD role via regulating DE miRNAs related to fatty acid metabolic process. Combined with the network pharmacological analysis, it was found that the DE miRNAs might affected the fatty acid biosynthesis pathway in the treatment of NAFLD by CSP. Molecular biology experiments have conformed the decreased the gene and protein levels of acetyl-CoA carboxylase alpha (ACACA), fatty acid synthase (FASN) and other fatty acid biosynthesis related enzymes on NAFLD rats after intervention of CSP.

CONCLUSIONS

CSP can significantly reduce hepatic lipid accumulation of NAFLD rat model induced by HFD, and its mechanism may be through the action of 15 miRNAs such as miR-34a-5p, miR-146a-5p, miR-20b-5p and miR-142-3p. Reduce the gene and protein expression levels of ACACA, FASN and other fatty acid biosynthesis related enzymes, thus reducing fatty acid biosynthesis. Based on an epigenetic perspective, this study explains the key anti-NAFLD mechanism of CSP via combination of microRNA sequencing and network pharmacological analysis, providing a new reference for the modernization of traditional Chinese medicine.

Drug regulation of microRNA

The scientific review provides the mechanisms of drug regulation of microRNA in the human body. To write the article, information was searched using Scopus, Web of Science, MEDLINE, PubMed, Google Scholar, Embase, Global Health, The Cochrane Library databases. To restore the reduced functional activity of microRNAs, replacement therapy is used, with modified synthetic analogs of endogenous microRNAs, and drugs that enhance the production of the body’s own microRNAs. The authors state that numerous studies have confirmed the effectiveness of miRNA replacement therapy. It is known that there are several groups of drugs among miRNA inhibitors: anti-miRNA oligonucleotides, miRNA traps, miRNA mimics that prevent miRNA binding; peptide nucleic acids, small-molecule inhibitors. The authors suggest that the expression of drug-metabolizing enzymes is controlled by nuclear receptors and transcription factors, epigenetic regulation such as DNA methylation and histone acetylation, and post-translational modification. It is emphasized that ursodeoxycholic acid modulates the expression of some miRNAs. It is known that probiotic bacteria can modulate the expression level of miRNA genes. The use of probiotics is accompanied by a change in the expression of nume­rous genes of the body involved in the regulation of the inflammatory response, allergic reactions, metabolism and other biological processes. Thus, modern science is intensively studying the potential of using drugs that restore miRNA content or inhibit miRNA acti­vity for the therapy of miRNA-dependent conditions. The results of scientific research confirmed the therapeutic effect of ursodeoxycholic acid and probiotic preparations due to the effect on the acti­vity of miRNA generation in hepatobiliary diseases. Therefore, the introduction into clinical practice of drugs than can modulate the content and expression of specific miRNAs will certainly open new perspectives in the treatment of patients with hepatobiliary diseases.

SIRT1 regulates endoplasmic reticulum stress-related organ damage

Endoplasmic reticulum (ER) stress plays a key role in the pathogenesis of several organ damages. Studies show that excessive ER stress (ERS) can destroy cellular homeostasis, causing cell damage and physiological dysfunction in various organs. In recent years, Sirtuin1 (SIRT1) has become a research hotspot on ERS. Increasing evidence suggests that SIRT1 plays a positive role in various ERS-induced organ damage via multiple mechanisms, including inhibiting cellular apoptosis and promoting autophagy. SIRT1 can also alleviate liver, heart, lung, kidney, and intestinal damage by inhibiting ERS. We discuss the possible mechanism of SIRT1, explore potential therapeutic targets of diseases, and provide a theoretical basis for treating ERS-related diseases.

Bile Acid Application in Cell-Targeting for Molecular Receptors in Relation to Hearing: A Comprehensive Review

Bile acids play important roles in the human body, and changes in their pool can be used as markers for various liver pathologies. In addition to their functional effects in modulating inflammatory responses and cellular survivability, the unconjugated or conjugated, secondary, or primary nature of bile acids accounts for their various ligand effects. The common hydrophilic bile acids have been used successfully as local treatment to resolve drug-induced cell damage or to ameliorate hearing loss. From various literature references, bile acids show concentration and tissue-dependent effects. Some hydrophobic bile acids act as ligands modulating vitamin D receptors, muscarinic receptors, and calcium-activated potassium channels, important proteins in the inner ear system. Currently, there are limited resources investigating the therapeutic effects of bile acid on hearing loss and little to no information on detecting bile acids in the remote ear system, let alone baseline bile acid levels and their prevalence in healthy and disease conditions. This review presents both hydrophilic and hydrophobic human bile acids and their tissue-specific effects in modulating cellular integrity, thus considering the possible effects and extended therapeutic applicability of bile acids to the inner ear tissue.

MiR-192-5p Ameliorates Hepatic Lipid Metabolism in Non-Alcoholic Fatty Liver Disease by Targeting Yy1

Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation in the liver. Clarifying the molecular mechanism of lipid metabolism is crucial for the treatment of NAFLD. We examined miR-192-5p levels in the livers of mice in which NAFLD was induced via a high-fat diet (HFD), as well as in mouse primary hepatocytes and human HepG2 cells treated with free fatty acids (FFAs). MiR-192-5p inhibitor was administered to NAFLD mice and hepatocytes to verify the specific function of miR-192-5p in NAFLD. We validated the target gene of miR-192-5p and further illustrated the effects of this miRNA on the regulation of triglyceride (TG) metabolism. We found that miR-192-5p was significantly increased in the livers of NAFLD mice and FFA-treated hepatocytes. Inhibition of miR-192-5p increased the accumulation of hepatic TGs and aggravated hepatic steatosis in NAFLD mice. In FFA-treated hepatocytes, miR-192-5p inhibitors markedly increased TG content, whereas overexpression of miR-192-5p reduced TG levels. Yin Yang 1 (Yy1) was identified as the target gene of miR-192-5p, which regulates TG synthesis via the YY1/fatty-acid synthase (FASN) pathway. Our results demonstrated that miR-192-5p should be considered a protective regulator in NAFLD that can inhibit hepatic TG synthesis by targeting Yy1.

Role of MicroRNAs in Dietary Interventions for Obesity and Obesity-Related Diseases

Obesity and related metabolic syndromes pose a serious threat to human health and quality of life. A proper diet is a safe and effective strategy to prevent and control obesity, thus maintaining overall health. However, no consensus exists on the connotations of proper diet, and it is attributed to various factors, including "nutritional dark matter" and the "matrix effect" of food. Accumulating evidence confirms that obesity is associated with the in vivo levels of miRNAs, which serve as potential markers and regulatory targets for obesity onset and progression; food-derived miRNAs can regulate host obesity by targeting the related genes or gut microbiota across the animal kingdom. Host miRNAs mediate food nutrient-gut microbiota-obesity interactions. Thus, miRNAs are important correlates of diet and obesity onset. This review outlines the recent findings on miRNA-mediated food interventions for obesity, thereby elucidating their potential applications. Overall, we provide new perspectives and views on the evaluation of dietary nutrition, which may bear important implications for dietary control and obesity prevention.

Effect of diet and genotype on the miRNome of mice with altered lipoprotein metabolism

The molecular mechanism by which lipid/lipoprotein biosynthesis is regulated in mammals involves a very large number of genes that are subject to multiple levels of regulation. miRNAs are recognized contributors to lipid homeostasis at the post-transcriptional level, although the elucidation of their role is made difficult by the multiplicity of their targets and the ability of more miRNAs to affect the same mRNAs. In this study, an evaluation of how miRNA expression varies in organs playing a key role in lipid/lipoprotein metabolism was conducted in control mice and in two mouse models carrying genetic ablations which differently affect low-density lipoprotein metabolism. Mice were fed a lipid-poor standard diet and a diet enriched in cholesterol and saturated fat. The results obtained showed that there are no miRNAs whose expression constantly vary with dietary or genetic changes. Furthermore, it appears that diet, more than genotype, impacts on organ-specific miRNA expression profiles.

miR-34a/SIRT1/HIF-1α axis is involved in cardiac angiogenesis of type 2 diabetic rats: The protective effect of sodium butyrate combined with treadmill exercise

Type 2 diabetes mellitus (T2DM) is one of the most common metabolic disorders worldwide. Recent research has indicated that sodium butyrate (NaB) affects glucose metabolism and exercise has an anti-hyperglycemic effect in diabetes. This study aimed to evaluate the effects of NaB and treadmill exercise on heart angiogenesis through the miR-34a/SIRT1/FOXO1-HIF-1α pathway. Diabetic animals received NaB (400 mg/kg daily, orally) and treadmill exercise for 6 weeks. The effect of NaB and treadmill exercise, alone or combined, on miR-34a expression, SIRT1, FOXO1, HIF-1α levels, and angiogenesis in diabetic heart tissue was measured. Diabetes caused increased miR-34a (p < 0.01) and FOXO1 (p < 0.001) expression levels. Also, SIRT1 (p < 0.001) and HIF-1α (not significant) expression levels were reduced in diabetic rats. NaB and treadmill exercise decreased miR-34a (respectively p < 0.05 and not significant) and FOXO1 (both p < 0.001) expression levels and improved SIRT1 (both not significant) and HIF-1α (respectively p < 0.01 and p < 0.001) levels. Also, NaB combined with treadmill exercise decreased miR-34a (p < 0.001) and FOXO1 (p < 0.001) expression levels, and elevated SIRT1 (p < 0.05) and HIF-1α (p < 0.001) levels in comparison with the diabetic group. NaB and treadmill exercises modulate the expression of miR-34a and the levels of SIRT1, FOXO1, and HIF-1α proteins, thus increasing angiogenesis in the heart tissue of diabetic rats. It can be concluded that NaB and treadmill exercise, alone or combined, may be useful in the treatment of diabetes through the miR-34a/SIRT1/FOXO1-HIF-1α pathway.

Role of microRNA in non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH): a comprehensive review

Non-alcoholic fatty liver disease (NAFLD) is a prevalent liver condition that affects people who do not overconsume alcohol. Uncertainties exist over how microRNAs (miRNAs) in the blood and liver relate to NAFLD. The aim of this narrative review was to investigate the role of miRNAs in the onset and progression of non-alcoholic steatohepatitis (NASH) from NAFLD, and explore their potential as diagnostic tools and treatment targets for NAFLD patients. Liver miRNA-34a levels were found to accurately represent the degree of liver damage, with lower levels suggesting more damage. In patients with NAFLD and severe liver fibrosis, higher levels of miRNA-193a-5p and miRNA-378d were found. Moreover, miRNA-34a, miRNA-122, and miRNA-192 levels might aid in differentiating NASH from NAFLD. Similar to this, miRNA-21 and miRNA-27 levels in rats were able to distinguish between steatosis and steatohepatitis. High-fat diets enhanced the expression of 15 distinct miRNAs in rats, and there were substantial differences in the miRNA expression patterns between obese and lean people. The results from the present review imply that miRNA microarrays and sequencing may be helpful diagnostic tools, and miRNAs may be a possible treatment target for patients with NAFLD.

miR34a-5p impedes CLOCK expression in chronodisruptive C57BL/6J mice and potentiates pro-atherogenic manifestations

INTRODUCTION

Altered circadian rhythms underlie manifestation of several cardiovascular disorders, however a little is known about the mediating biomolecules. Multiple transcriptional-translational feedback loops control circadian-clockwork wherein; micro RNAs (miRNAs) are known to manifest post transcriptional regulation. This study assesses miR34a-5p as a mediating biomolecule.

METHOD

8-10-week-old male C57BL/6J mice (n = 6/group) were subjected to photoperiodic manipulation induced chronodisruption and thoracic aortae were examined for miRNA, gene (qPCR) and protein (Immunoblot) expression studies. Histomorphological changes were assessed for pro-atherogenic manifestations (fibrillar arrangement, collagen/elastin ratio, intima-media thickening). Computational studies for miRNA-mRNA target prediction were done using TargetScan and miRDB. Correlative in vitro studies were done in serum synchronized HUVEC cells. Time point based studies were done at five time points (ZT 0, 6, 12, 18, 24) in 24h.

RESULTS

Chronodisruption induced hypomethylation in the promoter region of miR34a-5p, in the thoracic aortae, culminating in elevated miRNA titers. In a software-based detection of circadian-clock-associated targets of miR34a-5p, Clock and Sirt1 genes were identified. Moreover, miR34a-5p exhibited antagonist circadian oscillations to that of its target genes CLOCK and SIRT1 in endothelial cells. Luciferase reporter gene assay further showed that miR34a-5p interacts with the 3'UTR of the Clock gene to lower its expression, disturbing the operation of positive arm of circadian clock system. Elevated miR34a-5p and impeded SIRT1 expression in a chronodisruptive aortae exhibited pro-atherogenic changes observed in form of gene expression, increased collagen/elastin ratio, fibrillar derangement and intimal-media thickening.

CONCLUSION

The study reports for the first time chronodisruption mediated miR34a-5p elevation, its circadian expression and interaction with the 3'UTR of Clock gene to impede its expression. Moreover, elevated miR34a-5p and lowered SIRT1 expression in the chronodisruptive aortae lead off cause-consequence relationship of chronodisruption mediated proatherogenic changes.

Role of p53 suppression in the pathogenesis of hepatocellular carcinoma

In the world, hepatocellular carcinoma (HCC) is among the top 10 most prevalent malignancies. HCC formation has indeed been linked to numerous etiological factors, including alcohol usage, hepatitis viruses and liver cirrhosis. Among the most prevalent defects in a wide range of tumours, notably HCC, is the silencing of the p53 tumour suppressor gene. The control of the cell cycle and the preservation of gene function are both critically important functions of p53. In order to pinpoint the core mechanisms of HCC and find more efficient treatments, molecular research employing HCC tissues has been the main focus. Stimulated p53 triggers necessary reactions that achieve cell cycle arrest, genetic stability, DNA repair and the elimination of DNA-damaged cells’ responses to biological stressors (like oncogenes or DNA damage). To the contrary hand, the oncogene protein of the murine double minute 2 (MDM2) is a significant biological inhibitor of p53. MDM2 causes p53 protein degradation, which in turn adversely controls p53 function. Despite carrying wt-p53, the majority of HCCs show abnormalities in the p53-expressed apoptotic pathway. High p53 in-vivo expression might have two clinical impacts on HCC: (1) Increased levels of exogenous p53 protein cause tumour cells to undergo apoptosis by preventing cell growth through a number of biological pathways; and (2) Exogenous p53 makes HCC susceptible to various anticancer drugs. This review describes the functions and primary mechanisms of p53 in pathological mechanism, chemoresistance and therapeutic mechanisms of HCC.

Insight into the Inter-Organ Crosstalk and Prognostic Role of Liver-Derived MicroRNAs in Metabolic Disease Progression

Dysfunctional hepatic metabolism has been linked to numerous diseases, including non-alcoholic fatty liver disease, the most common chronic liver disorder worldwide, which can progress to hepatic fibrosis, and is closely associated with insulin resistance and cardiovascular diseases. In addition, the liver secretes a wide array of metabolites, biomolecules, and microRNAs (miRNAs) and many of these secreted factors exert significant effects on metabolic processes both in the liver and in peripheral tissues. In this review, we summarize the involvement of liver-derived miRNAs in biological processes with an emphasis on delineating the communication between the liver and other tissues associated with metabolic disease progression. Furthermore, the review identifies the primary molecular targets by which miRNAs act. These consolidated findings from numerous studies provide insight into the underlying mechanism of various metabolic disease progression and suggest the possibility of using circulatory miRNAs as prognostic predictors and therapeutic targets for improving clinical intervention strategies.

Dietary Curcumin Attenuates Hepatic Cellular Senescence by Suppressing the MAPK/NF-κB Signaling Pathway in Aged Mice

Dietary interventions with bioactive compounds have been found to suppress the accumulation of senescent cells and senescence-associated secretory phenotypes (SASPs). One such compound, curcumin (CUR), has beneficial health and biological effects, including antioxidant and anti-inflammatory properties, but its ability to prevent hepatic cellular senescence is unclear. The objective of this study was to investigate the effects of dietary CUR as an antioxidant on hepatic cellular senescence and determine its benefits on aged mice. We screened the hepatic transcriptome and found that CUR supplementation led to the downregulation of senescence-associated hepatic gene expressions in both usually fed and nutritionally challenged aged mice. Our results showed that CUR supplementation enhanced antioxidant properties and suppressed mitogen-activated protein kinase (MAPK) signaling cascades in the liver, particularly c-Jun N-terminal kinase (JNK) in aged mice and p38 in diet-induced obese aged mice. Furthermore, dietary CUR decreased the phosphorylation of nuclear factor-κB (NF-κB), a downstream transcription factor of JNK and p38, and inhibited the mRNA expression of proinflammatory cytokines and SASPs. The potency of CUR administration was demonstrated in aged mice via enhanced insulin homeostasis along with declined body weight. Taken together, these results suggest that CUR supplementation may be a nutritional strategy to prevent hepatic cellular senescence.

Regorafenib inhibits EphA2 phosphorylation and leads to liver damage via the ERK/MDM2/p53 axis

The hepatotoxicity of regorafenib is one of the most noteworthy concerns for patients, however the mechanism is poorly understood. Hence, there is a lack of effective intervention strategies. Here, by comparing the target with sorafenib, we show that regorafenib-induced liver injury is mainly due to its nontherapeutic target Eph receptor A2 (EphA2). EphA2 deficiency attenuated liver damage and cell apoptosis under regorafenib treatment in male mice. Mechanistically, regorafenib inhibits EphA2 Ser897 phosphorylation and reduces ubiquitination of p53 by altering the intracellular localization of mouse double minute 2 (MDM2) by affecting the extracellular signal-regulated kinase (ERK)/MDM2 axis. Meanwhile, we found that schisandrin C, which can upregulate the phosphorylation of EphA2 at Ser897 also has protective effect against the toxicity in vivo. Collectively, our findings identify the inhibition of EphA2 Ser897 phosphorylation as a key cause of regorafenib-induced hepatotoxicity, and chemical activation of EphA2 Ser897 represents a potential therapeutic strategy to prevent regorafenib-induced hepatotoxicity.

Peroxisome Proliferator-Activated Receptor-γ as a Target and Regulator of Epigenetic Mechanisms in Nonalcoholic Fatty Liver Disease

Peroxisome proliferator-activated receptor-γ (PPARγ) belongs to the superfamily of nuclear receptors that control the transcription of multiple genes. Although it is found in many cells and tissues, PPARγ is mostly expressed in the liver and adipose tissue. Preclinical and clinical studies show that PPARγ targets several genes implicated in various forms of chronic liver disease, including nonalcoholic fatty liver disease (NAFLD). Clinical trials are currently underway to investigate the beneficial effects of PPARγ agonists on NAFLD/nonalcoholic steatohepatitis. Understanding PPARγ regulators may therefore aid in unraveling the mechanisms governing the development and progression of NAFLD. Recent advances in high-throughput biology and genome sequencing have greatly facilitated the identification of epigenetic modifiers, including DNA methylation, histone modifiers, and non-coding RNAs as key factors that regulate PPARγ in NAFLD. In contrast, little is still known about the particular molecular mechanisms underlying the intricate relationships between these events. The paper that follows outlines our current understanding of the crosstalk between PPARγ and epigenetic regulators in NAFLD. Advances in this field are likely to aid in the development of early noninvasive diagnostics and future NAFLD treatment strategies based on PPARγ epigenetic circuit modification.

Suppression of SIRT1/FXR signaling pathway contributes to oleanolic acid-induced liver injury

Oleanolic acid (OA) is a pentacyclic triterpenoid compound used clinically for acute and chronic hepatitis. However, high dose or long-term use of OA causes hepatotoxicity, which limits its clinical application. Hepatic Sirtuin (SIRT1) participates in the regulation of FXR signaling and maintains hepatic metabolic homeostasis. This study was designed to determine whether SIRT1/FXR signaling pathway contributes to the hepatotoxicity caused by OA. C57BL/6J mice were administered with OA for 4 consecutive days to induce hepatotoxicity. The results showed that OA suppressed the expression of FXR and its downstream targets CYP7A1, CYP8B1, BSEP and MRP2 at both mRNA and protein levels, breaking the homeostasis of bile acid leading to hepatotoxicity. However, treatment with FXR agonist GW4064 noticeably attenuated hepatotoxicity caused by OA. Furthermore, it was found that OA inhibited protein expression of SIRT1. Activation of SIRT1 by its agonist SRT1720 significantly improved OA-induced hepatotoxicity. Meanwhile, SRT1720 significantly reduced the inhibition of protein expression of FXR and FXR-downstream proteins. These results suggested that OA may cause hepatotoxicity through SIRT1 dependent suppression of FXR signaling pathway. In vitro experiments confirmed that OA suppressed protein expressions of FXR and its targets through inhibition of SIRT1. It was further revealed that silencing of HNF1α with siRNA significantly weakened regulatory effects of SIRT1 on the expression of FXR as well as its target genes. In conclusion, our study reveals that SIRT1/FXR pathway is crucial in OA-induced hepatotoxicity. Activation of SIRT1/HNF1α/FXR axis may represent a novel therapeutic target for ameliorating OA and other herb-induced hepatotoxicity.

Liquiritin alleviates alpha-naphthylisothiocyanate-induced intrahepatic cholestasis through the Sirt1/FXR/Nrf2 pathway

Liquiritin (LQ) is an important monomer active component in flavonoids of licorice. The objective of this study was to evaluate the hepatoprotective effects of LQ in cholestatic mice. LQ (40 or 80 mg/kg) was intragastrically administered to mice once daily for 6 days, and mice were treated intragastrically with a single dosage of ANIT (75 mg/kg) on the 5th day. On the 7th day, mice were sacrificed to collect blood and livers. The mRNA and protein levels were determined by qRT-PCR and western blot assay. We also conducted systematical assessments of miRNAs expression profiles in the liver. LQ ameliorated ANIT-induced cholestatic liver injury, as evidenced by reduced serum biochemical markers and attenuated pathological changes in liver. Pretreatment of LQ reduced the increase of malondialdehyde, TNF-α, and IL-1β induced by ANIT. Moreover, ANIT suppressed the expression of Sirt1 and FXR in liver tissue, which was weakened in the LQ pre-treatment group. LQ enhanced the nuclear expression of Nrf2, which was increased in the ANIT group. LQ also increased the mRNA expressions of bile acid transporters Bsep, Ntcp, Mrp3, and Mrp4. Furthermore, a miRNA deep sequencing analysis revealed that LQ had a global regulatory effect on the hepatic miRNA expression. Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis showed that the differentially expressed miRNAs were mainly related to metabolic pathways, endocytosis, and MAPK signaling pathway. Collectively, LQ attenuated hepatotoxicity and cholestasis by regulating the expression of Sirt1/FXR/Nrf2 and the bile acid transporters, indicating that LQ might be an effective approach for cholestatic liver diseases.

MicroRNAs as Biomarkers and Therapeutic Targets for Nonalcoholic Fatty Liver Disease: A Narrative Review

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world. However, biomarkers for NAFLD diagnosis and liver-specific drugs for treatment are lacking. This article reviews the possibility of circulating miRNAs in the diagnosis and treatment of NAFLD diseases and focuses on several well-studied miRNAs to provide preclinical data for subsequent related studies.

METHODS

Related articles were identified through searches of the PubMed database for literature published from 2010 to December 2022. Search terms included NAFLD, microRNA, biomarker, diagnosis, and therapy.

FINDINGS

Current research data indicate that some key circulating miRNAs may be used as diagnostic biomarkers of NAFLD and the combination of several miRNAs improves diagnostic performance. In addition, some preclinical trials using cell and mouse models provide a basis for some miRNAs as potential therapeutic targets.

IMPLICATIONS

Current evidence suggests that circulating miRNAs are potential noninvasive biomarkers for clinical diagnosis of NAFLD, which needs to be validated in more heterogeneous and larger cohorts. In addition, several miRNAs regulate multiple downstream pathways related to the pathophysiology of NAFLD in a cell- and tissue-specific manner, making them attractive drug therapeutic targets for NAFLD. However, more preclinical and clinical trials are needed for these miRNAs to become therapeutic targets of NAFLD.

Liver-specific deletion of microRNA-34a alleviates ductular reaction and liver fibrosis during experimental cholestasis

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterized by inflammatory responses and fibrotic scar formation leading to cholestasis. Ductular reaction and liver fibrosis are typical liver changes seen in human PSC and cholestasis patients. The current study aimed to clarify the role of liver-specific microRNA-34a in the cholestasis-associated ductular reaction and liver fibrosis. We demonstrated that miR-34a expression was significantly increased in human PSC livers along with the enhanced ductular reaction, cellular senescence, and liver fibrosis. A liver-specific miR-34a knockout mouse was established by crossing floxed miR-34a mice with albumin-promoter-driven Cre mice. Bile duct ligation (BDL) induced liver injury characterized by necrosis, fibrosis, and immune cell infiltration. In contrast, liver-specific miR-34a knockout in BDL mice resulted in decreased biliary ductular pathology associated with the reduced cholangiocyte senescence and fibrotic responses. The miR-34a-mediated ductular reactions may be functioning through Sirt-1-mediated senescence and fibrosis. The hepatocyte-derived conditioned medium promoted LPS-induced fibrotic responses and senescence in cholangiocytes, and miR-34a inhibitor suppressed these effects, further supporting the involvement of paracrine regulation. In conclusion, we demonstrated that liver-specific miR-34a plays an important role in ductular reaction and fibrotic responses in a BDL mouse model of cholestatic liver disease.

Circulating miRNAs associated with nonalcoholic fatty liver disease

MicroRNAs (miRNAs) are secreted from cells as either protein-bound or enclosed in extracellular vesicles. Circulating liver-derived miRNAs are modifiable by weight-loss or insulin-sensitizing treatments, indicating that they could be important biomarker candidates for diagnosis, monitoring, and prognosis in nonalcoholic liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Unfortunately, the noninvasive diagnosis of NASH and fibrosis remains a key challenge, which limits case finding. Current diagnostic guidelines, therefore, recommend liver biopsies, with risks of pain and bleeding for the patient and substantial healthcare costs. Here, we summarize mechanisms of RNA secretion and review circulating RNAs associated with NAFLD and NASH for their biomarker potential. Few circulating miRNAs are consistently associated with NAFLD/NASH: miR-122, miR-21, miR-34a, miR-192, miR-193, and the miR-17-92 miRNA-cluster. The hepatocyte-enriched miRNA-122 is consistently increased in NAFLD and NASH but decreased in liver cirrhosis. Circulating miR-34a, part of an existing diagnostic algorithm for NAFLD, and miR-21 are consistently increased in NAFLD and NASH. MiR-192 appears to be prominently upregulated in NASH compared with NAFDL, whereas miR-193 was reported to distinguish NASH from fibrosis. Various members of miRNA cluster miR-17-92 are reported to be associated with NAFLD and NASH, although with less consistency. Several other circulating miRNAs have been reported to be associated with fatty liver in a few studies, indicating the existence of more circulating miRNAs with relevant as diagnostic markers for NAFLD or NASH. Thus, circulating miRNAs show potential as biomarkers of fatty liver disease, but more information about phenotype specificity and longitudinal regulation is needed.

Global Trends of Lipid Metabolism Research in Epigenetics Field: A Bibliometric Analysis from 2012-2021

Most common diseases are characterized by metabolic changes, among which lipid metabolism is a hotspot. Numerous studies have demonstrated a strong correlation between epigenetics and lipid metabolism. This study of publications on the epigenetics of lipid metabolism searched in the Web of Science Core Collection from 2012 to 2022, and a total of 3685 publications were retrieved. Much of our work focused on collecting the data of annual outputs, high-yielding countries and authors, vital journals, keywords and citations for qualitative and quantitative analysis. In the past decade, the overall number of publications has shown an upward trend. China (1382, 26.69%), the United States (1049, 20.26%) and Italy (206, 3.98%) were the main contributors of outputs. The Chinese Academy of Sciences and Yale University were significant potential cooperation institutions. Articles were mainly published in the "International Journal of Molecular Sciences". In addition to typical liver-related diseases, "ferroptosis", "diabetes" and "atherosclerosis" were identified as potential research topics. "NF-κB" and "oxidative stress" were referred to frequently in publications. METTL3 and ALKBH5 were the most discussed m⁶A-related enzymes in 2022. Our study revealed research hotspots and new trends in the epigenetics of lipid metabolism, hoping to provide significant information and inspiration for researchers to further explore new directions.

Epigenetics and mitochondrial dysfunction insights into the impact of the progression of non-alcoholic fatty liver disease

A metabolic problem occurs when regular functions of the body are disrupted due to an undesirable imbalance. Nonalcoholic fatty liver disease (NAFLD) is considered as one of the most common in this category. NAFLD is subclassified and progresses from lipid accumulation to cirrhosis before advancing to hepatocellular cancer. In spite of being a critical concern, the standard treatment is inadequate. Metformin, silymarin, and other nonspecific medications are used in the management of NAFLD. Aside from this available medicine, maintaining a healthy lifestyle has been emphasized as a means of combating this. Epigenetics, which has been attributed to NAFLD, is another essential feature of this disease that has emerged as a result of several sorts of research. The mechanisms by which DNA methylation, noncoding RNA, and histone modification promote NAFLD have been extensively researched. Another organelle, mitochondria, which play a pivotal role in biological processes, contributes to the global threat. Individuals with NAFLD have been documented to have a multitude of alterations and malfunctioning. Mitochondria are mainly concerned with the process of energy production and regulation of the signaling pathway on which the fate of a cell relies. Modulation of mitochondria leads to elevated lipid deposition in the liver. Further, changes in oxidation states result in an impaired balance between the antioxidant system and reactive oxygen species directly linked to mitochondria. Hence mitochondria have a definite role in potentiating NAFLD. In this regard, it is essential to consider the role of epigenetics as well as mitochondrial contribution while developing a medication or therapy with the desired accuracy.

Short-term fructose feeding alters tissue metabolic pathways by modulating microRNAs expression both in young and adult rats

Dietary high fructose (HFrD) is known as a metabolic disruptor contributing to the development of obesity, diabetes, and dyslipidemia. Children are more sensitive to sugar than adults due to the distinct metabolic profile, therefore it is especially relevant to study the metabolic alterations induced by HFrD and the mechanisms underlying such changes in animal models of different ages. Emerging research suggests the fundamental role of epigenetic factors such as microRNAs (miRNAs) in metabolic tissue injury. In this perspective, the aim of the present study was to investigate the involvement of miR-122-5p, miR-34a-5p, and miR-125b-5p examining the effects induced by fructose overconsumption and to evaluate whether a differential miRNA regulation exists between young and adult animals. We used young rats (30 days) and adult rats (90 days) fed on HFrD for a short period (2 weeks) as animal models. The results indicate that both young and adult rats fed on HFrD exhibit an increase in systemic oxidative stress, the establishment of an inflammatory state, and metabolic perturbations involving the relevant miRNAs and their axes. In the skeletal muscle of adult rats, HFrD impair insulin sensitivity and triglyceride accumulation affecting the miR-122-5p/PTP1B/P-IRS-1(Tyr612) axis. In liver and skeletal muscle, HFrD acts on miR-34a-5p/SIRT-1: AMPK pathway resulting in a decrease of fat oxidation and an increase in fat synthesis. In addition, liver and skeletal muscle of young and adult rats exhibit an imbalance in antioxidant enzyme. Finally, HFrD modulates miR-125b-5p expression levels in liver and white adipose tissue determining modifications in de novo lipogenesis. Therefore, miRNA modulation displays a specific tissue trend indicative of a regulatory network that contributes in targeting genes of various pathways, subsequently yielding extensive effects on cell metabolism.

Hepato-Protective Effects of Delta-Tocotrienol and Alpha-Tocopherol in Patients with Non-Alcoholic Fatty Liver Disease: Regulation of Circulating MicroRNA Expression

MicroRNAs (miRNAs) play a key role in the regulation of genes for normal metabolism in the liver. Dysregulation of miRNAs is involved in the development and progression of non-alcoholic fatty liver disease (NAFLD). We aimed to explore changes in circulating miRNA expression in response to delta-tocotrienol (δT3) and alpha-tocopherol (αTF) supplementation and correlate them with relevant biochemical markers in patients with NAFLD. In total, 100 patients with NAFLD were randomized to either receive δT3 (n = 50) 300 mg or αTF (n = 50) 268 mg twice/day for 48 weeks. Plasma expression of miRNA-122, -21, -103a-2, -421, -375 and -34a were determined at baseline, 24 and 48 weeks of intervention using RT-qPCR. Both δT3 and αTF significantly downregulated expression of miRNA-122, -21, -103a-2, -421, -375 and -34a. Moreover, δT3 was more effective than αTF in reducing expression of miRNA-375 and -34a. A significant correlation was observed between miRNA expression and biochemical markers of hepatic steatosis, insulin resistance (IR), oxidative stress (OS), inflammation and apoptosis. δT3 and αTF exert hepato-protective effects by downregulating miRNAs involved in hepatic steatosis, IR, OS, inflammation and apoptosis in patients with NAFLD. Furthermore, δT3 has more pronounced effects than αTF in reducing miR-375 and miR-34a, which are linked to regulation of inflammation and apoptosis.

Exploring the Regulatory Role of ncRNA in NAFLD: A Particular Focus on PPARs

Liver diseases are responsible for global mortality and morbidity and are a significant cause of death worldwide. Consequently, the advancement of new liver disease targets is of great interest. Non-coding RNA (ncRNA), such as microRNA (miRNA) and long ncRNA (lncRNA), has been proven to play a significant role in the pathogenesis of virtually all acute and chronic liver disorders. Recent studies demonstrated the medical applications of miRNA in various phases of hepatic pathology. PPARs play a major role in regulating many signaling pathways involved in various metabolic disorders. Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease in the world, encompassing a spectrum spanning from mild steatosis to severe non-alcoholic steatohepatitis (NASH). PPARs were found to be one of the major regulators in the progression of NAFLD. There is no recognized treatment for NAFLD, even though numerous clinical trials are now underway. NAFLD is a major risk factor for developing hepatocellular carcinoma (HCC), and its frequency increases as obesity and diabetes become more prevalent. Reprogramming anti-diabetic and anti-obesity drugs is an effective therapy option for NAFLD and NASH. Several studies have also focused on the role of ncRNAs in the pathophysiology of NAFLD. The regulatory effects of these ncRNAs make them a primary target for treatments and as early biomarkers. In this study, the main focus will be to understand the regulation of PPARs through ncRNAs and their role in NAFLD.

Bioinformatics analysis reveals molecular connections between non-alcoholic fatty liver disease (NAFLD) and COVID-19

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has devastatingly impacted people's lives. Non-alcoholic fatty liver disease (NAFLD) is fatal comorbidity of COVID-19 seen with potential risk factors to develop severe symptoms. This research focuses on determining and elucidating the molecular factors and connections that might contribute to the severity of SARS-CoV-2 infection in NAFLD patients. Here, we comprehensively inspected the genes involved in NAFLD and SARS-CoV-2 entry factors (SCEFs) found by searching through the DisGeNet database and literature review, respectively. Further, we identified the SCEFs-related proteins through protein-protein interaction (PPI) network construction, MCODE, and Cytohubba. Next, the shared genes involved in NAFLD and SARS-CoV-2 entry, and hub gene were determined, followed by the GO and KEGG pathways analysis. X2K database was used to construct the upstream regulatory network of hub genes, as well as to identify the top ten candidates of transcription factors (TFs) and protein kinases (PKs). PPI analysis identified connections between 4 top SCEFs, including ACE, ADAM17, DPP4, and TMPRSS2 and NAFLD-related genes such as ACE, DPP4, IL-10, TNF, and AKT1. GO and KEGG analysis revealed the top ten biological processes and pathways, including cytokine-mediated signaling, PI3K-Akt, AMPK, and mTOR signaling pathways. The upstream regulatory network revealed that AKT1 and MAPK14 as important PKs and HIF1A and SP1 as important TFs associated with AKT1, IL-10, and TNF. The molecular connections identified between COVID-19 and NAFLD may shed light on discovering the causes of the severity of SARS-CoV-2 infected NAFLD patients.

MiR-133a-3p/Sirt1 epigenetic programming mediates hypercholesterolemia susceptibility in female offspring induced by prenatal dexamethasone exposure

Mounting evidence indicates that adverse intrauterine conditions increase offspring's hypercholesterolemia susceptibility in adulthood. This study aimed to confirm prenatal dexamethasone exposure (PDE)-induced hypercholesterolemia susceptibility in female adult offspring rats, and elucidate its intrauterine programming mechanism. Pregnant Wistar rats were injected with dexamethasone subcutaneously (0, 0.1 and 0.2 mg/kg·d) from gestational day (GD) 9 to 20. Serum and liver of the female offspring were collected at GD21 and postnatal week (PW) 12 and 28. PDE offspring showed elevated serum total cholesterol (TCH) levels and a cholesterol phenotype of high cardiovascular disease risk at PW12 and PW28. The histone acetylation levels of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (Hmgcr) and its expression were consistently increased in the PDE offspring both in utero and after birth. Moreover, PDE promoted glucocorticoid receptor (GR) nuclear translocation and miR-133a-3p expression and inhibited sirtuin-1 (Sirt1) expression in the fetal liver. In vitro, dexamethasone increased intracellular and supernatant TCH levels and miR-133a-3p expression, decreased SIRT1 expression, and promoted HMGCR histone acetylation and expression in bone marrow mesenchymal stem cells (BMSCs) hepatoid differentiated cells and HepG2 cell line. GR siRNA, miR-133a-3p inhibitor or SIRT1 overexpression reversed dexamethasone-induced downstream molecular and phenotypic changes. Furthermore, elevated TCH levels in umbilical cord blood and increased HMGCR expression in peripheral blood mononuclear cells (PBMCs) were observed in human female neonates who had received dexamethasone treatment during pregnancy. In conclusion, PDE can cause persistent enhancement of hepatic cholesterol synthesis function before and after birth through GR/miR-133a-3p/Sirt1 pathway, eventually leading to increased hypercholesterolemia susceptibility in female offspring rats.

miR-139 Protects Liver Tissue Damage and Oxidative Stress in Diabetic Mice by Up-Regulating (Silent Mating Type Information Regulation 2 Homolog-1) SIRT1

Diabetes affects human health. This study aimed to investigate the molecular regulation mechanism of miR-139 on liver injury and oxidative stress in diabetic mice. The diabetic mice were divided into miR-139 inhibitor group, si-SIRT group, miR-139 mimic group, and the mRNA expression and protein level of miR-139 and SIRT1 were analyzed, respectively. Bioinformatics revealed the relationship between miR-139 and SIRT1. In addition, histological analysis and oxidation reaction indicators were performed on mouse livers induced by high glucose. After induction, a mouse diabetes model was established with highly expressed ALT. Bioinformatics found that miR-139 negatively regulated SIRT1. Furthermore, markers of hepatic oxidative stress were increased and blood glucose levels decreased in mice overexpressing miR-139. Up-regulation of miR-139 can protect the liver tissue of diabetic mice from oxidative stress injury by inhibiting the expression of SIRT1, and si-SIRT treatment reversed the increased blood glucose level and oxidative stress injury caused by the reduction of miR-139.

Investigating microRNAs to Explain the Link between Cholesterol Metabolism and NAFLD in Humans: A Systematic Review

Non-Alcoholic Fatty Liver Disease (NAFLD) is characterized by hepatic free cholesterol accumulation. In addition, microRNAs (miRNAs) might be involved in NAFLD development. Therefore, we systematically reviewed the literature to examine the link between miRNAs and cholesterol metabolism in NAFLD. Nineteen studies were retrieved by a systematic search in September 2022. From these papers, we evaluated associations between 13 miRNAs with NAFLD and cholesterol metabolism. Additionally, their diagnostic potential was examined. Four miRNAs (miR122, 34a, 132 and 21) were associated with cholesterol metabolism and markers for NAFLD. MiR122 was upregulated in serum of NAFLD patients, increased with disease severity and correlated with HDL-C, TAG, VLDL-C, AST, ALT, ALP, lobular inflammation, hepatocellular ballooning and NAFLD score. Serum and hepatic levels also correlated. Serum and hepatic miR34a levels were increased in NAFLD, and correlated with VLDL-C and TAG. Serum miR379 was also higher in NAFLD, especially in early stages, while miR21 gave ambiguous results. The diagnostic properties of these miRNAs were comparable to those of existing biomarkers. However, serum miR122 levels appeared to be elevated before increases in ALT and AST were evident. In conclusion, miR122, miR34a, miR21 and miR132 may play a role in the development of NAFLD via effects on cholesterol metabolism. Furthermore, it needs to be explored if miRNAs 122, 34a and 379 could be used as part of a panel in addition to established biomarkers in early detection of NAFLD.

Bile acids-gut microbiota crosstalk contributes to the improvement of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) occurs that cannot effectively use the insulin. Insulin Resistance (IR) is a significant characteristic of T2DM which is also an essential treatment target in blood glucose regulation to prevent T2DM and its complications. Bile acids (BAs) are one group of bioactive metabolites synthesized from cholesterol in liver. BAs play an important role in mutualistic symbiosis between host and gut microbiota. It is shown that T2DM is associated with altered bile acid metabolism which can be regulated by gut microbiota. Simultaneously, BAs also reshape gut microbiota and improve IR and T2DM in the bidirectional communications of the gut-liver axis. This article reviewed the findings on the interaction between BAs and gut microbiota in improving T2DM, which focused on gut microbiota and its debinding function and BAs regulated gut microbiota through FXR/TGR5. Meanwhile, BAs and their derivatives that are effective for improving T2DM and other treatments based on bile acid metabolism were also summarized. This review highlighted that BAs play a critical role in the glucose metabolism and may serve as therapeutic targets in T2DM, providing a reference for discovering and screening novel therapeutic drugs.

The Implications of Noncoding RNAs in the Evolution and Progression of Nonalcoholic Fatty Liver Disease (NAFLD)-Related HCC

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver pathology worldwide. Meanwhile, liver cancer represents the sixth most common malignancy, with hepatocellular carcinoma (HCC) as the primary, most prevalent subtype. Due to the rising incidence of metabolic disorders, NAFLD has become one of the main contributing factors to HCC development. However, although NAFLD might account for about a fourth of HCC cases, there is currently a significant gap in HCC surveillance protocols regarding noncirrhotic NAFLD patients, so the majority of NAFLD-related HCC cases were diagnosed in late stages when survival chances are minimal. However, in the past decade, the focus in cancer genomics has shifted towards the noncoding part of the genome, especially on the microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), which have proved to be involved in the regulation of several malignant processes. This review aims to summarize the current knowledge regarding some of the main dysregulated, noncoding RNAs (ncRNAs) and their implications for NAFLD and HCC development. A central focus of the review is on miRNA and lncRNAs that can influence the progression of NAFLD towards HCC and how they can be used as potential screening tools and future therapeutic targets.

miR-375 upregulates lipid metabolism and inhibits cell proliferation involved in chicken fatty liver formation and inheritance via targeting recombination signal binding protein for immunoglobulin kappa J region (RBPJ)

Poultry is susceptible to fatty liver which lead to decrease egg production and increase mortality. But the potential molecular mechanisms remain largely unclear. In the current study, in combination with transcriptome sequencing and miRNA sequencing data analysis from F1 generation of the normal liver and fatty liver tissues, the differentially expressed miR-375 and its target gene RBPJ were screened and verified. The expression levels of miR-375 and RBPJ gene in the liver between control and fatty liver groups of F0-F3 generation for Jingxing-Huang (JXH) chicken are different significantly (P < 0.05 or P < 0.01). And downregulated RBPJ expression can promote TG content and lipid droplets in primary hepatocytes cultured in vitro (P < 0.01). Cell proliferation-related genes, including PMP22, IGF-1, IGF-2, and IGFBP-5, increased or decreased significantly after overexpression or knock-down RBPJ (P < 0.05 or P < 0.01), respectively. This study uniquely revealed that miR-375 induced lipid synthesis and inhibited cell proliferation may partly due to regulation of RBPJ expression, thereby involving in fatty liver formation and inheritance in chicken. The results could be useful in identifying candidate genes and revealing the pathogenesis of fatty liver that may be used for disease-resistance selective breeding in chicken.