ERK-dependent mTOR pathway is involved in berberine-induced autophagy in hepatic steatosis

Berberine directly targets AKR1B10 protein to modulate lipid and glucose metabolism disorders in NAFLD

ETHNOPHARMACOLOGICAL RELEVANCE

Berberine (BBR) is the main active component from Coptidis rhizome, a well-known Chinese herbal medicine used for metabolic diseases, especially diabetes for thousands of years. BBR has been reported to cure various metabolic disorders, such as nonalcoholic fatty liver disease (NAFLD). However, the direct proteomic targets and underlying molecular mechanism of BBR against NAFLD remain less understood.

AIM OF THE STUDY

To investigate the direct target and corresponding molecular mechanism of BBR on NAFLD is the aim of the current study.

MATERIALS AND METHODS

High-fat diet (HFD)-fed mice and oleic acid (OA) stimulated HepG2 cells were utilized to verify the beneficial impacts of BBR on glycolipid metabolism profiles. The click chemistry in proteomics, DARTS, CETSA, SPR and fluorescence co-localization analysis were conducted to identify the targets of BBR for NAFLD. RNA-seq and shRNA/siRNA were used to investigate the downstream pathways of the target.

RESULTS

BBR improved hepatic steatosis, ameliorated insulin resistance, and reduced TG levels in the NAFLD models. Importantly, Aldo-keto reductase 1B10 (AKR1B10) was first proved as the target of BBR for NAFLD. The gene expression of AKR1B10 increased significantly in the NAFLD patients' liver tissue. We further demonstrated that HFD and OA increased AKR1B10 expression in the C57BL/6 mice's liver and HepG2 cells, respectively, whereas BBR decreased the expression and activities of AKR1B10. Moreover, the knockdown of AKR1B10 by applying shRNA/siRNA profoundly impacted the beneficial effects on the pathogenesis of NAFLD by BBR. Meanwhile, the changes in various proteins (ACC1, CPT-1, GLUT2, etc.) are responsible for hepatic lipogenesis, fatty acid oxidation, glucose uptake, etc. by BBR were reversed by the knockdown of AKR1B10. Additionally, RNA-seq was used to identify the downstream pathway of AKR1B10 by examining the gene expression of liver tissues from HFD-fed mice. Our findings revealed that BBR markedly increased the protein levels of PPARα while downregulating the expression of PPARγ. However, various proteins of PPAR signaling pathways remained unaffected post the knockdown of AKR1B10.

CONCLUSIONS

BBR alleviated NAFLD via mediating PPAR signaling pathways through targeting AKR1B10. This study proved that AKR1B10 is a novel target of BBR for NAFLD treatment and helps to find new targets for the treatment of NAFLD by using active natural compounds isolated from traditional herbal medicines as the probe.

Traditional Chinese medicine and plant-derived natural products in regulating triglyceride metabolism: Mechanisms and therapeutic potential

The incidence of cardiometabolic disease is increasing globally, with a trend toward younger age of onset. Among these, atherosclerotic cardiovascular disease is a leading cause of mortality worldwide. Despite the efficacy of traditional lipid-lowering drugs, such as statins, in reducing low-density lipoprotein cholesterol levels, a significant residual risk of cardiovascular events remains, which is closely related to unmet triglyceride (TG) targets. The clinical application of current TG-lowering Western medicines has certain limitations, necessitating alternative or complementary therapeutic strategies. Traditional Chinese medicine (TCM) and plant-derived natural products, known for their safety owing to their natural origins and diverse biological activities, offer promising avenues for TG regulation with potentially fewer side effects. This review systematically summarises the mechanisms of TG metabolism and subsequently reviews the regulatory effects of TCM and plant-derived natural products on TG metabolism, including the inhibition of TG synthesis (via endogenous and exogenous pathways), promotion of TG catabolism, regulation of fatty acid absorption and transport, enhancement of lipophagy, modulation of the gut microbiota, and other mechanisms. In conclusion, through a comprehensive analysis of recent studies, this review consolidates the multifaceted regulatory roles of TCM and plant-derived natural products in TG metabolism and elucidates their potential as safer, multi-target therapeutic agents in managing hypertriglyceridemia and mitigating cardiovascular risk, thereby providing a basis for new drug development.

Neuroprotective Properties of Berberine: Molecular Mechanisms and Clinical Implications

Berberine (BBR), an isoquinoline alkaloid natural product, is isolated primarily from Coptis chinensis and other Berberis plants. BBR possesses various bioactivities, including antioxidant, anti-inflammation, anticancer, immune-regulation, and antimicrobial activities. Growing scientific evidence underscores BBR's substantial neuroprotective potential, prompting increased interest and scrutiny. In this comprehensive review, we elucidate the neuroprotective attributes of BBR, delineate the underlying molecular mechanisms, and assess its clinical safety and efficacy. The multifaceted molecular mechanisms responsible for BBR's neuroprotection encompass the attenuation of oxidative stress, mitigation of inflammatory responses, inhibition of apoptotic pathways, facilitation of autophagic processes, and modulation of CYP450 enzyme activities, neurotransmitter levels, and gut microbiota composition. Furthermore, BBR engages numerous signaling pathways, including the PI3K/Akt, NF-κB, AMPK, CREB, Nrf2, and MAPK pathways, to confer its neuroprotective effects. This comprehensive review aims to provide a substantial knowledge base, stimulate broader scientific discourse, and facilitate advancements in the application of BBR for neuroprotection.

Different types of cell death and their shift in shaping disease

Cell death is the irreversible stop of life. It is also the basic physiological process of all organisms which involved in the embryonic development, organ maintenance and autoimmunity of the body. In recent years, we have gained more comprehension of the mechanism in cell death and have basically clarified the different types of "programmed cell death", such as apoptosis, necroptosis, autophagy, and pyroptosis, and identified some key genes in these processes. However, in these previous studies, the conversion between different cell death modes and their application in diseases are rarely explored. To sum up, although many valued discoveries have been discovered in the field of cell death in recent years, there are still many unknown problems to be solved in this field. Facts have proved that cell death is a very complex game, and a series of core players have the ability to destroy the delicate balance of the cell environment, from survival to death, from anti-inflammatory to pro-inflammatory. With the thorough research of the complex regulatory mechanism of cell death, there will certainly be exciting new research in this field in the next few years. The sake of this paper is to emphasize the complex mechanism of overturning the balance between different cell fates and provide relevant theoretical basis for the connection between cell death transformation and disease treatment in the future.

Epiberberine regulates lipid synthesis through SHP (NR0B2) to improve non-alcoholic steatohepatitis

Epiberberine (EPI), extracted from Rhizome Coptidis, has been shown to attenuate hyperlipidemia in vivo. Herein we have studied the mechanism by which EPI is active against non-alcoholic steatohepatitis (NASH) using, mice fed on a methionine- and choline-deficient (MCD) diet and HepG2 cells exposed to free fatty acids (FFA). We show that small heterodimer partner (SHP) protein is key in the regulation of lipid synthesis. In HepG2 cells and in the livers of MCD-fed mice, EPI elevated SHP levels, and this was accompanied by a reduction in sterol regulatory element-binding protein-1c (SREBP-1c) and FASN. Therefore, EPI reduced triglyceride (TG) accumulation in steatotic hepatocytes, even in HepG2 cells treated with siRNA-SHP, and also improved microbiota. Thus, EPI suppresses hepatic TG synthesis and ameliorates liver steatosis by upregulating SHP and inhibiting the SREBP1/FASN pathway, and improves gut microbiome.

Caffeine can alleviate non-alcoholic fatty liver disease by augmenting LDLR expression via targeting EGFR

Increasing low-density lipoprotein receptor (LDLR) protein levels represents a key strategy for the prevention and treatment. Berberine can reportedly alleviate non-alcoholic fatty liver disease (NAFLD) by increasing the LDLR expression in an ERK1/2 signaling-dependent manner of NAFLD. Studies have shown that caffeine can inhibit fat deposition in the livers of mice; however, caffeine has not been reported to alleviate NAFLD by augmenting the LDLR expression via targeting EGFR. Here, an MTT assay, western blotting, RT-qPCR, immunohistochemistry, and surface plasmon resonance (SPR) analysis were used to investigate the role of caffeine in low-density lipoprotein cholesterol (LDL-C) clearance both in vitro and in vivo. In vitro, we found that caffeine could activate the EGFR-ERK1/2 signaling pathway in HepG2 cells, leading to increased LDLR mRNA and protein expression, and this effect could be inhibited by cetuximab. The SPR assay results have indicated that caffeine may increase the LDLR expression by directly binding to the EGFR extracellular domain and activating the EGFR-ERK1/2 signaling pathway. In vivo, caffeine markedly improved fatty liver and related blood indices in ApoE KO mice with high-fat-diet-induced NAFLD. Consistent with our in vitro results, we found that caffeine could also activate EGFR-ERK1/2 signaling and promote the LDLR expression in ApoE KO mice. In summary, caffeine can enhance the LDLR expression by directly binding to EGFR and activating the EGFR-ERK1/2 signaling pathway. EGFR signaling may represent a novel target for the prevention and treatment of NAFLD.

Preparation, physicochemical characterization, and bioactivity evaluation of berberine-entrapped albumin nanoparticles

Berberine (BBR) is an isoquinoline alkaloid with several clinical therapeutic applications. Its low water solubility, absorption, and cellular bioavailability diminish BBR's therapeutic efficacy. In this study, BBR was encapsulated into bovine serum albumin nanoparticles (BSA NPs) core to reduce BBR limitations and enhance its clinical therapeutic properties. Several physicochemical characterization tools, such as Dynamic Light Scattering and Ultraviolet-Visible spectroscopic measurements, field emission transmission electron microscopy surface morphology, Fourier transforms infrared spectroscopy, thermal stability analysis, and releasing studies, were used to evaluate the BBR-BSA NPs. Compared to BBR, BBR-BSA nanoparticles demonstrated superior free radical scavenging and antioxidant capacities, anti-hemolytic and anticoagulant efficacies, and antimicrobial activities, as demonstrated by the findings of the in vitro studies. Furthermore, a stressed pancreatic rat model was induced using a high-fat, high-sucrose diet plus carbon tetrachloride injection. The in vivo results revealed that BBR-BSA NPs substantially restored peripheral glucose metabolism and insulin sensitivity. Oral administration of BBR-BSA NPs also improved pancreatic β-cells homeostasis, upregulated pancreatic antioxidant mechanisms, inhibited oxidants generation, and attenuated oxidative injury in the stressed pancreatic tissues. In conclusion, our in vitro and in vivo results confirmed that BBR-BSA NPs demonstrated more potent antioxidant properties and restored pancreatic homeostasis compared to BBR.

Preclinical Evidence of Berberine on Non-Alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of Animal Studies

As lifestyle and diet structure impact our health, non-alcoholic fatty liver disease (NAFLD) is prevalent all over the world. Some phytomedicines containing berberine (BBR) have been extensively used for centuries in Ayurvedic and traditional Chinese medicine. The goal of this systematic review is to investigate the preclinical evidence of BBR on NAFLD models. The following relevant databases, including Web of Science, PubMed, the Cochrane Library, and Embase, were retrieved from inception to May 2021. The content involved BBR on different animal models for the treatment of NAFLD. The SYstematic Review Center for Laboratory animal Experimentation (SYRCLE) Animal Experiment Bias Risk Assessment Tool was used to assess the methodological quality and RevMan 5.4 software was used to conduct the meta-analysis based on the Cochrane tool. A total of 31 studies involving 566 animals were included, of which five models and five animal breeds were reported. The results showed that TC, TG, ALT, AST, HDL-C, LDL-C, FBG, FINS, and FFA in the group treated with BBR were significantly restored compared with those in the model group. HOMA-IR had a significant downward trend, but the result was not significantly different (P = 0.08). The subgroup analysis of the different models and different animal breeds indicated that BBR could ameliorate the aforementioned indicator levels, although some results showed no significant difference. Finally, we summarized the molecular mechanisms by which berberine regulated NAFLD/NASH, mainly focusing on activating the AMPK pathway, improving insulin sensitivity and glucose metabolism, regulating mitochondrial function, reducing inflammation and oxidative stress, regulating cell death and ER stress, reducing DNA methylation, and regulating intestinal microenvironment and neurotoxicity. The preclinical evidence suggested that BBR might be an effective and promising drug for treating NAFLD/NASH. In addition, further studies with more well-designed researches are needed to confirm this conclusion.

Protective Mechanism of Berberine on Human Retinal Pigment Epithelial Cells against Apoptosis Induced by Hydrogen Peroxide via the Stimulation of Autophagy

Age-related macular degeneration (AMD) is a major cause of severe and irreversible vision loss with limited effective therapies. Diminished autophagy and increased oxidative damage caused by ROS in the retinal pigment epithelium (RPE) have been implicated in the pathogenesis of AMD, and strategies aimed at enhancing autophagy are likely to protect these cells from oxidative damage. We have previously shown that berberine (BBR), an isoquinoline alkaloid isolated from Chinese herbs, was able to protect human RPE cells from H₂O₂-induced oxidative damage through AMPK activation. However, the precise mechanisms behind this protective effect remain unclear. Given the essential role of AMPK in autophagy activation, we postulated that BBR may confer protection against H₂O₂-induced oxidative damage by stimulating AMPK-dependent autophagy. Our results showed that BBR was able to induce autophagy in D407 cells, whereas autophagy inhibitor PIKIII or silencing of LC3B blocked the protective effect of BBR. Further analysis showed that BBR activated the AMPK/mTOR/ULK1 signaling pathways and that both pharmacological and genetic inhibitions of the AMPK pathway abolished the autophagy-stimulating effect of BBR. Similar results were obtained in primary cultured human RPE cells. Taken together, these results demonstrate that BBR is able to stimulate autophagy in D407 cells via the activation of AMPK pathway and that its protective effect against H₂O₂-induced oxidative damage relies on its autophagy-modulatory effect. Our findings also provide evidence to support the potential application of BBR in preventing and treating AMD.

Pterocarpus marsupium extract extends replicative lifespan in budding yeast

As the molecular mechanisms of biological aging become better understood, there is growing interest in identifying interventions that target those mechanisms to promote extended health and longevity. The budding yeast Saccharomyces cerevisiae has served as a premier model organism for identifying genetic and molecular factors that modulate cellular aging and is a powerful system in which to evaluate candidate longevity interventions. Here we screened a collection of natural products and natural product mixtures for effects on the growth rate, mTOR-mediated growth inhibition, and replicative lifespan. No mTOR inhibitory activity was detected, but several of the treatments affected growth rate and lifespan. The strongest lifespan shortening effects were observed for green tea extract and berberine. The most robust lifespan extension was detected from an extract of Pterocarpus marsupium and another mixture containing Pterocarpus marsupium extract. These findings illustrate the utility of the yeast system for longevity intervention discovery and identify Pterocarpus marsupium extract as a potentially fruitful longevity intervention for testing in higher eukaryotes.

New Insights Into the Role of Autophagy in Liver Surgery in the Setting of Metabolic Syndrome and Related Diseases

Visceral obesity is an important component of metabolic syndrome, a cluster of diseases that also includes diabetes and insulin resistance. A combination of these metabolic disorders damages liver function, which manifests as non-alcoholic fatty liver disease (NAFLD). NAFLD is a common cause of abnormal liver function, and numerous studies have established the enormously deleterious role of hepatic steatosis in ischemia-reperfusion (I/R) injury that inevitably occurs in both liver resection and transplantation. Thus, steatotic livers exhibit a higher frequency of post-surgical complications after hepatectomy, and using liver grafts from donors with NAFLD is associated with an increased risk of post-surgical morbidity and mortality in the recipient. Diabetes, another MetS-related metabolic disorder, also worsens hepatic I/R injury, and similar to NAFLD, diabetes is associated with a poor prognosis after liver surgery. Due to the large increase in the prevalence of MetS, NAFLD, and diabetes, their association is frequent in the population and therefore, in patients requiring liver resection and in potential liver graft donors. This scenario requires advancement in therapies to improve postoperative results in patients suffering from metabolic diseases and undergoing liver surgery; and in this sense, the bases for designing therapeutic strategies are in-depth knowledge about the molecular signaling pathways underlying the effects of MetS-related diseases and I/R injury on liver tissue. A common denominator in all these diseases is autophagy. In fact, in the context of obesity, autophagy is profoundly diminished in hepatocytes and alters mitochondrial functions in the liver. In insulin resistance conditions, there is a suppression of autophagy in the liver, which is associated with the accumulation of lipids, being this is a risk factor for NAFLD. Also, oxidative stress occurring in hepatic I/R injury promotes autophagy. The present review aims to shed some light on the role of autophagy in livers undergoing surgery and also suffering from metabolic diseases, which may lead to the discovery of effective therapeutic targets that could be translated from laboratory to clinical practice, to improve postoperative results of liver surgeries when performed in the presence of one or more metabolic diseases.

Molecular updates on berberine in liver diseases: Bench to bedside

Liver diseases are life-threatening illnesses and are the major cause of mortality and morbidity worldwide. These may include liver fibrosis, liver cirrhosis, and drug-induced liver toxicity. Liver diseases have a wide prevalence globally and the fifth most common cause of death among all gastrointestinal disorders. Several novel therapeutic approaches have emerged for the therapy of liver diseases that may provide better clinical outcomes with improved safety. The use of phytochemicals for the amelioration of liver diseases has gained considerable popularity. Berberine (BBR), an isoquinoline alkaloid of the protoberberine type, has emerged as a promising molecule for the treatment of gastrointestinal disorders. Accumulating studies have proved the hepatoprotective effects of BBR. BBR has been shown to modulate multiple signaling pathways implicated in the pathogenesis of liver diseases including Akt/FoxO2, PPAR-γ, Nrf2, insulin, AMPK, mTOR, and epigenetic pathways. In the present review, we have emphasized the important pharmacological activities and mechanisms of BBR in liver diseases. Further, we have reviewed various pharmacokinetic and toxicological barriers of this promising phytoconstituent. Finally, formulation-based novel approaches are also summarized to overcome the clinical hurdles for BBR.

Autophagy in Hepatic Steatosis: A Structured Review

Steatosis is the accumulation of neutral lipids in the cytoplasm. In the liver, it is associated with overeating and a sedentary lifestyle, but may also be a result of xenobiotic toxicity and genetics. Non-alcoholic fatty liver disease (NAFLD) defines an array of liver conditions varying from simple steatosis to inflammation and fibrosis. Over the last years, autophagic processes have been shown to be directly associated with the development and progression of these conditions. However, the precise role of autophagy in steatosis development is still unclear. Specifically, autophagy is necessary for the regulation of basic metabolism in hepatocytes, such as glycogenolysis and gluconeogenesis, response to insulin and glucagon signaling, and cellular responses to free amino acid contents. Also, genetic knockout models for autophagy-related proteins suggest a critical relationship between autophagy and hepatic lipid metabolism, but some results are still ambiguous. While autophagy may seem necessary to support lipid oxidation in some contexts, other evidence suggests that autophagic activity can lead to lipid accumulation instead. This structured literature review aims to critically discuss, compare, and organize results over the last 10 years regarding rodent steatosis models that measured several autophagy markers, with genetic and pharmacological interventions that may help elucidate the molecular mechanisms involved.

Research progress in use of traditional Chinese medicine monomer for treatment of non-alcoholic fatty liver disease

With the improvement of people's living standards and the change of eating habits, non-alcoholic fatty liver disease (NAFLD) has gradually become one of the most common chronic liver diseases in the world. However, there are no effective drugs for the treatment of NAFLD. Therefore, it is urgent to find safe, efficient, and economical anti-NAFLD drugs. Compared with western medicines that possess fast lipid-lowering effect, traditional Chinese medicines (TCM) have attracted increasing attention for the treatment of NAFLD due to their unique advantages such as multi-targets and multi-channel mechanisms of action. TCM monomers have been proved to treat NAFLD through regulating various pathways, including inflammation, lipid production, insulin sensitivity, mitochondrial dysfunction, autophagy, and intestinal microbiota. In particular, peroxisome proliferator-activated receptor α (PPAR-α), sterol regulatory element-binding protein 1c (SREBP-1c), nuclear transcription factor kappa (NF-κB), phosphoinositide 3-kinase (PI3K), sirtuin1 (SIRT1), AMP-activated protein kinase (AMPK), p53 and nuclear factor erythroid 2-related factor 2 (Nrf2) are considered as important molecular targets for ameliorating NAFLD by TCM monomers. Therefore, by searching PubMed, Web of Science and SciFinder databases, this paper updates and summarizes the experimental and clinical evidence of TCM monomers for the treatment of NAFLD in the past six years (2015-2020), thus providing thoughts and prospects for further exploring the pathogenesis of NAFLD and TCM monomer therapies.

The pharmacological activity of berberine, a review for liver protection

Liver plays an important role in bile synthesis, metabolic function, degradation of toxins, new substances synthesis in body. However, hepatopathy morbidity and mortality are increasing year by year around the world, which become a major public health problem. Traditional Chinese medicine (TCM) has a prominent role in the treatment of liver diseases due to its definite curative effect and small side effects. The hepatoprotective effect of berberine has been extensively studied, so we comprehensively summarize the pharmacological activities of lipid metabolism regulation, bile acid adjustment, anti-inflammation, oxidation resistance, anti-fibrosis and anti-cancer and so on. Besides, the metabolism and toxicity of berberine and its new formulations to improve its effectiveness are expounded, providing a reference for the safe and effective clinical use of berberine.

2‑Hydroxypropyl‑β‑cyclodextrin blocks autophagy flux and triggers caspase‑8‑mediated apoptotic cascades in HepG2 cells

The cyclodextrin derivative, 2‑Hydroxypropyl-β‑cyclodextrin (HPβCD), from the cyclodextrin family is widely used as a drug carrier and offers promising strategies for treating neurodegenerative diseases and atherosclerosis regression. However, its side effects are not fully understood. Therefore, the aim of the present study was to investigate the possible adverse effects of relatively high concentrations of HPβCD on hepatocytes. It was found that a high dose (20 mM) of HPβCD treatment significantly inhibited the AKT/mTOR pathway and disrupted infusion of autophagosomes and lysosomes, which rapidly led to massive autophagosome accumulation in HepG2 cells. The autophagosomal membrane serves as a platform for caspase‑8 oligomerization, which is considered as the key step for its self‑activation. Using flow cytometry and TUNEL assay, increased apoptosis of HepG2 cells treated with a high dose HPβCD (20 mM) for 48 h was observed. In addition, western blotting results demonstrated that the expression of cleaved‑caspase‑8 was positively associated with microtubule‑associated protein 1 light chain 3 BII expression, which is an indicator of autophagosome level in the cytoplasm. Therefore, the present study provided novel evidence that HPβCD might be a potential risk contributing to the pathophysiological process of hepatic diseases, especially in an autophagy‑deficient state.

Goldenseal (Hydrastis canadensis L.) and its active constituents: A critical review of their efficacy and toxicological issues

Goldenseal (Hydrastis canadensis L.) is a medicinal plant widely used in various traditional systems of medicine and as a food supplement. It has been traditionally used by Native Americans as a coloring agent and as medicinal remedy for common diseases and conditions like wounds, digestive disorders, ulcers, skin and eye ailments, and cancer. Over the years, goldenseal has become a popular food supplement in the USA and other regions. The rhizome of this plant has been used for the treatment of a variety of diseases including, gastrointestinal disorders, ulcers, muscular debility, nervous prostration, constipation, skin and eye infections, cancer, among others. Berberine is one of the most bioactive alkaloid that has been identified in different parts of goldenseal. The goldenseal extract containing berberine showed numerous therapeutic effects such as antimicrobial, anti-inflammatory, hypolipidemic, hypoglycemic, antioxidant, neuroprotective (anti-Alzheimer's disease), cardioprotective, and gastrointestinal protective. Various research finding suggest the health promoting effects of goldenseal components and their extracts. However, few studies have also suggested the possible neurotoxic, hepatotoxic and phototoxic activities of goldenseal extract and its alkaloids. Thus, large randomized, double-blind clinical studies need to be conducted on goldenseal supplements and their main alkaloids to provide more evidence on the mechanisms responsible for the pharmaceutical activity, clinical efficacy and safety of these products. Thus, it is very important to review the scientific information about goldenseal to understand about the current scenario.

Mesenchymal stem cell-derived exosomes exert ameliorative effects in type 2 diabetes by improving hepatic glucose and lipid metabolism via enhancing autophagy

Background

Mesenchymal stem cell (MSC)-based therapy is currently considered to be an effective treatment strategy for diabetes and hepatic disorders, such as liver cirrhosis and non-alcoholic fatty liver disease. Exosomes are important mediators of cellular connections, and increasing evidence has suggested that exosomes derived from MSCs may be used as direct therapeutic agents; their mechanisms of action, however, remain largely unclear. Here, we evaluated the efficacy and molecular mechanisms of human umbilical cord MSC-derived exosomes (HucMDEs) on hepatic glucose and lipid metabolism in type 2 diabetes mellitus (T2DM).

Methods

HucMDEs were used to treat T2DM rats, as well as palmitic acid (PA)-treated L-O2 cells, in order to determine the effects of HucMDEs on hepatic glucose and lipid metabolism. To evaluate the changes in autophagy and potential signaling pathways, autophagy-related proteins (BECN1, microtubule-associated protein 1 light chain 3 beta [MAP 1LC3B]), autophagy-related genes (ATGs, ATG5, and ATG7), AMP-activated protein kinase (AMPK), and phosphorylated AMPK (p-AMPK) were assessed by Western blotting.

Results

HucMDEs promoted hepatic glycolysis, glycogen storage, and lipolysis, and reduced gluconeogenesis. Additionally, autophagy potentially contributed to the effects of HucMDE treatment. Transmission electron microscopy revealed an increased formation of autophagosomes in HucMDE-treated groups, and the autophagy marker proteins, BECN1 and MAP 1LC3B, were also increased. Moreover, autophagy inhibitor 3-methyladenine significantly reduced the effects of HucMDEs on glucose and lipid metabolism in T2DM rats. Based on its phosphorylation status, we found that the AMPK signaling pathway was activated and induced autophagy in T2DM rats and PA-treated L-O2 cells. Meanwhile, the transfection of AMPK siRNA or application of the AMPK inhibitor, Comp C, weakened the therapeutic effects of HucMDEs on glucose and lipid metabolism.

Conclusions

These findings demonstrate that HucMDEs improved hepatic glucose and lipid metabolism in T2DM rats by activating autophagy via the AMPK pathway, which provides novel evidence suggesting the potential for HucMDEs in clinically treating T2DM patients.

Berberine represses human gastric cancer cell growth in vitro and in vivo by inducing cytostatic autophagy via inhibition of MAPK/mTOR/p70S6K and Akt signaling pathways

Berberine, an isoquinoline alkaloid from Coptidis Rhizoma, has been characterized as a potential anticancer drug due to its good anti-tumor effects. However, the molecular mechanisms involved in anti-gastric cancer remain poorly understood. Herein, the role of berberine in gastric cancer suppression by inducing cytostatic autophagy in vitro and in vivo was first investigated. Results showed that berberine induced an obvious growth inhibitory effect on gastric cancer BGC-823 cells without toxicity to human peripheral blood mononuclear cells. Treatment with berberine triggered cell autophagy, as demonstrated by the punctuate distribution of monodansylcadaverine staining and GFP-LC3, as well as the LC3-II, Beclin-1 and p-ULK1 promotion, and p62 degradation. Inhibition of autophagy by 3-MA, CQ, Baf-A1 and BECN1 siRNA obviously increased cell viability of berberine-exposed gastric cancer cells, which confirmed the anti-cancer role of autophagy induced by berberine. Mechanistic studies showed that berberine inhibited mTOR, Akt and MAPK (ERK, JNK and p38) pathways thereby inducing autophagy. Inhibition of above pathways increases berberine induced autophagy and cytotoxicity. Interestingly, mTOR/p70S6K was inhibited by the MAPK but not Akt. Furthermore, inhibition of autophagy reversed berberine down-regulated mTOR, Akt and MAPK. In xenografts, the berberine induced autophagy leads to suppression of tumor proliferation with no side-effect, and western blotting displayed an apparent attenuation of p-mTOR, p-p70S6K, p-Akt, p-ERK, p-JNK and p-p38 in tumors from berberine treated mice. Briefly, these results indicated that berberine repressed human gastric cancer cell growth in vitro and in vivo by inducing cytostatic autophagy via inhibition of MAPK/mTOR/p70S6K and Akt, and provided a molecular basis for the treatment of gastric cancer.

Berberine as a potential autophagy modulator

Today, pharmacognosy is considered a valuable science in the prevention and treatment of diseases. Among herbals, Berberine is an isoquinoline alkaloid found in the Berberis species. Surprisingly, it shows antimicrobial, antiviral, antidiarrheal, antipyretic, and anti-inflammatory potential. Furthermore, it diminishes drug resistance in cancer therapy and enhances tumor suppression in part through autophagy and cell cycle arrest mechanisms. In the present review, we discuss the effect of berberine on diverse cellular pathways and describe how berberine acts as an autophagy modulator to adjust physiologic and pathologic conditions and diminishes drug resistance in cancer therapy.

Dietary N-Carbamylglutamate (NCG) alleviates liver metabolic disease and hepatocyte apoptosis by suppressing ERK1/2-mTOR-S6K1 signal pathway via promoting endogenous arginine synthesis in Japanese seabass (Lateolabrax japonicus)

N-Carbamylglutamate (NCG), an analogue of N-acetylglutamate (NAG), can promote the synthesis of endogenous Arginine (Arg) in mammals, but not well studied in fish. This study was conducted to investigate the capacity of Arg endogenous synthesis by NCG, and the effects of various dietary NCG doses on growth performance, hepatic health and underlying nutrient regulation metabolism on ERK1/2-mTOR-S6K1 signaling pathway in Japanese seabass (Lateolabrax japonicus). Four experimental diets were prepared with NCG supplement levels of 0 (N0), 360 (N360), 720 (N720) and 3600 (N3600) mg/kg, in which N360 was at the maximum recommended level authorized by MOA, China in fish feed, and the N720 and N3600 levels were 2 and 10-fold of N360, respectively. Each diet was fed to 6 replicates with 30 Japanese seabass (initial body weight, IBW = 11.67 ± 0.02 g) in each tank. The results showed that the dietary NCG supplementation had no significant effects on the SGR and morphometric parameters of Japanese seabass, but 360-720 mg/kg NCG inclusion promoted PPV, while the 10-fold (3600 mg/kg) overdose of NCG had remarkably negative effects with significantly reduced feed efficiency, PPV and LPV. We found that Japanese seabass can utilize 360-720 mg/kg NCG to synthesis Arg to improve the amino acid metabolism by increasing plasma Arg and up-regulating intestinal ASL gene expression. Increased plasma GST and decreased MDA indicated the improved antioxidant response. Dietary NCG inclusion decreased plasma IgM and down-regulated the mRNA levels of inflammation (TNF-α and IL8), apoptosis (caspase family) and fibrosis (TGF-β1) related genes in the liver. The immunofluorescence examination revealed significantly decreased hepatic apoptosis and necrosis signals in the NCG groups. The ameliorated liver function and histological structure were closely related to the improved lipid metabolism parameters with decreased plasma VLDL and hepatic TG and NEFA accumulation, down-regulated fatty acid and cholesterol synthesis and simultaneously increased lipolysis gene mRNA levels, which regulated by inhibiting phosphorylation of ERK1/2-mTOR-S6K1 signaling pathway. Consuming 3600 mg/kg of dietary NCG is not safe for Japanese seabass culturing with the significantly increased FCR and decreased protein and lipid retention, and reduced plasma ALB. Accordingly, the observed efficacy and safety level of dietary NCG in the diet of Japanese seabass is 720 mg/kg.

Atg7 mediates renal tubular cell apoptosis in vancomycin nephrotoxicity through activation of PKC-δ

Recent studies have shown that autophagy exhibits a renoprotective role in various models of acute kidney injury (AKI). However, its role in vancomycin (Van)-induced AKI remains largely unclarified. This study was the first to indicate that autophagy was rapidly activated in both human kidney-2 cells and renal tissues, and mammalian target of rapamycin (mTOR) was inactivated via the suppression of ERK1/2 and mTOR during Van treatment. Interestingly, for both in vitro and in vivo experiments, the suppression of autophagy via chloroquine and PT-Atg7-KO significantly ameliorated Van-induced kidney injury and renal tubular cell apoptosis. Global gene expression analysis indicated that the expression levels of 6159 genes were induced by Van treatment in the kidney cortical tissues of PT-Atg7 wild-type mice, and 18 of them were notably suppressed in PT-Atg7-KO mice. These 18 genes were further classified as programmed cell death, protein binding, signal transduction, E3 ubiquitin ligase, nucleoside diphosphate kinase activity, and E1-like activating enzyme. Unexpectedly, following Van treatment, PKC-δ expression was found to be highest among the 4 genes related to cell death, which was remarkably suppressed in vitro and in PT-Atg7-KO mice. In addition, Atg7 could induce renal cell apoptosis during Van treatment via binding to PKC-δ. Likewise, the inhibition of PKCδ ameliorated Van-induced apoptosis in human kidney-2 cells and kidney tissues. Furthermore, the data showed that PT-Atg7-KO exerted a renoprotective effect against Van-induced nephrotoxicity, but this effect was lost after injection with myc-tagged PKCδ. Taken altogether, these results indicate that Van induces autophagy by suppressing the activation of the ERK1/2 and mTOR signaling pathway. In addition, Atg7 mediates Van-induced AKI through the activation of PKCδ. In sum, autophagy inhibition may serve as a novel therapeutic target for treating nephrotoxic AKI induced by Van.-Xu, X., Pan, J., Li, H., Li, X., Fang, F., Wu, D., Zhou, Y., Zheng, P., Xiong, L., Zhang, D. Atg7 mediates renal tubular cell apoptosis in vancomycin nephrotoxicity through activation of PKC-δ.

Effects of berberine on glucose-lipid metabolism, inflammatory factors and insulin resistance in patients with metabolic syndrome

Effects of berberine on glucose-lipid metabolism, inflammatory factors and insulin resistance in patients with metabolic syndrome were investigated. Eighty patients with metabolic syndrome treated in Linyi Central Hospital from January 2017 to December 2017 were selected and divided into control group (n=40) and observation group (n=40). Patients in control group were treated with regular therapy using the Western medicine and drugs, while those in observation group, based on the treatment in control group, were treated with berberine. Changes in relevant indexes to blood glucose and lipid metabolisms and inflammatory factors were compared between the two groups. The correlation of inflammatory factor with fasting blood glucose, insulin resistance, triglyceride and total cholesterol was analyzed. At 1 month after treatment, levels of fasting blood glucose, 2 h postprandial blood glucose, insulin resistance index and blood lipid indexes in both groups were lower than those at 1 week after treatment (P<0.05). At 1 month after treatment, levels of fasting blood glucose, 2 h postprandial blood glucose, insulin resistance index and blood lipid indexes in observation group were significantly lower than those in control group during the same period (P<0.05). Moreover, levels of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in both groups at 1 month after treatment were lower than those at 1 week after treatment (P<0.05), and they were lower in observation group at 1 month after treatment than those in control group during the same period (P<0.05). Finally, hs-CRP was positively correlated with fasting blood glucose, insulin resistance, total cholesterol and triglyceride. The combined application of berberine in patients with metabolic syndrome can effectively regulate blood glucose and blood lipid of patients, alleviate insulin resistance and reduce the level of inflammatory response in the body.

Combating Neurodegenerative Diseases with the Plant Alkaloid Berberine: Molecular Mechanisms and Therapeutic Potential

Neurodegenerative diseases are among the most serious health problems affecting millions of people worldwide. Such diseases are characterized by a progressive degeneration and / or death of neurons in the central nervous system. Currently, there are no therapeutic approaches to cure or even halt the progression of neurodegenerative diseases. During the last two decades, much attention has been paid to the neuroprotective and anti-neurodegenerative activities of compounds isolated from natural products with high efficacy and low toxicity. Accumulating evidence indicates that berberine, an isoquinoline alkaloid isolated from traditional Chinese medicinal herbs, may act as a promising anti-neurodegenerative agent by inhibiting the activity of the most important pathogenic enzymes, ameliorating intracellular oxidative stress, attenuating neuroinflammation, triggering autophagy and protecting neurons against apoptotic cell death. This review attempts to summarize the current state of knowledge regarding the therapeutic potential of berberine against neurodegenerative diseases, with a focus on the molecular mechanisms that underlie its effects on Alzheimer's, Parkinson's and Huntington's diseases.

Non-alcoholic Fatty Liver Disease Induced by Perinatal Exposure to Bisphenol a Is Associated With Activated mTOR and TLR4/NF-κB Signaling Pathways in Offspring Rats

Accumulating evidence suggests a role of bisphenol A (BPA) in non-alcoholic fatty liver disease (NAFLD), and its mechanism may be related to the up-regulation of lipogenic genes, but the mechanism of BPA induced lipogenic gene expression remains unknown. The aim of this study was to investigate the effects of perinatal exposure to BPA on NAFLD and its mechanisms. Pregnant Sprague-Dawley rats had access to drinking water containing 1 or 10 μg/ml BPA from gestational day 6 to post-natal day 21. For 5 weeks after weaning, offspring drank normal water without BPA. Body weight, lipid profile and the expression of genes or proteins involved in mTOR mediated lipid metabolism and autophagy, as well as inflammatory response were investigated in the 8-wk-old offspring of different genders. The results showed that body weight was increased only in females, however, males, and females from dams treated with BPA had significantly excess visceral adipose tissue, which was consistent with adipocyte hypertrophy. Elevated TG levels and up-regulation of lipogenic genes or proteins in liver, such as sterol regulatory element binding protein 1 (SREBP1), acetyl-CoA carboxylase 1 (ACC1), and fatty acid synthase (FAS) were consistent with increased liver lipid droplets in offspring exposed to BPA. Compared with controls, the protein levels of InsR, p-IRS-1, IRS-1, TSC1, and TSC2 were decreased, p-PI3K, p-Akt (S473), p-Akt (T308), p-mTOR, and mTOR were increased, and the impaired autophagic degradation was evidenced by increased protein levels of p62, although the levels of p-ULK1, Beclin1, and LC3B proteins were increased in liver of BPA-exposed offspring. The levels of TLR4 and NF-κB proteins were also significantly increased, and ERα protein was significantly decreased in BPA-exposed offspring. Our findings indicate that perinatal exposure to BPA causes the development of NAFLD in both female and male offspring, which is associated with up-regulation of lipogenic genes, dysregulated autophagy and activated inflammatory response involving the PI3K/Akt/mTOR and TLR4/NF-κB pathways.

Attenuation of hepatic steatosis by purple sweet potato colour is associated with blocking Src/ERK/C/EBPβ signalling in high-fat-diet–treated mice

Our previous work showed that purple sweet potato colour (PSPC), a class of naturally occurring anthocyanins, effectively improved hepatic glucose metabolic dysfunction in high-fat-diet (HFD)–treated mice. This study investigated the effects of PSPC on HFD-induced hepatic steatosis and the signalling events associated with these effects. Mice were divided into 4 groups: control group, HFD group, HFD+PSPC group, and PSPC group. PSPC was administered daily for 20 weeks at oral doses of 700 mg/(kg·day)−1). Our results showed that PSPC significantly improved obesity and related metabolic parameters, as well as liver injury in HFD-treated mice. Moreover, PSPC dramatically attenuated hepatic steatosis in HFD-treated mice. PSPC markedly prevented oxidative stress-mediated Src activation in HFD-treated mouse livers. Furthermore, PSPC feeding remarkably suppressed mitogen-activated protein kinase kinase/extracellular-signal-regulated kinase (MEK/ERK) signalling and consequent CCAAT/enhancer binding protein β (C/EBPβ) activation and restored AMPK activation in HFD-treated mouse livers, which was confirmed by U0126 treatment. Ultimately, PSPC feeding dramatically reduced protein expression of FAS and CD36 and the activation of ACC, and increased the protein expression of CPT1A in the livers of HFD-treated mice, indicating decreased lipogenesis and fatty acid uptake and enhanced fatty acid oxidation. In conclusion, PSPC exhibited beneficial effects on hepatic steatosis, which were associated with blocking Src and C/EBPβ activation.

Down-regulation of lncRNA-NEAT1 alleviated the non-alcoholic fatty liver disease via mTOR/S6K1 signaling pathway

Without effective medical interventions for complete reverse of NAFLD, it needs to urgently explore the underlying molecular mechanisms of non-alcoholic fatty liver disease (NAFLD) to offer a novel therapeutic strategy for people suffering from NAFLD. Sprague-Dawley (SD) rats were used to establish the NAFLD animal model. Lipofectamine 2000 was used to silence or over-express NEAT1. The expression of NEAT1 and the mRNA levels of ACC and FAS were determined by qRT-PCR. Western blot assays were performed to detect the expression of ACC and FAS at protein levels and the related protein levels of mTOR/S6K1 signaling pathway. The levels of liver triglyceride (TG), serum total cholesterol (TC), ALT, and AST were assessed by an automatic biochemistry analyzer. The levels of liver TG and serum cholesterol were obviously up-regulated in NAFLD rat model. The level of NEAT1 expression and the mRNA levels of ACC and FAS were obviously enhanced in NAFLD model both in vivo and in vitro. Knockdown of NEAT1 could also reduce the elevation of ACC and FAS induced by FFA in liver cells. Moreover, inhibition of mTOR/S6K1 pathway presented with the same effect with knockdown of NEAT1 on the expression of ACC and FAS mRNA levels. The injection of si-NEAT1 lentivirus was performed to treat NAFLD of rats and the obvious efficacy for NAFLD rats was achieved. In a word, the down-regulated level of NEAT1 could remit the non-alcoholic fatty liver disease through mTOR/S6K1 signaling pathway in rats.

Erzhi Pill® Repairs Experimental Liver Injury via TSC/mTOR Signaling Pathway Inhibiting Excessive Apoptosis

The present study aimed to investigate the mechanism of hepatoprotective effect of Erzhi Pill (EZP) on the liver injury via observing TSC/mTOR signaling pathway activation. The experimental liver injury was induced by 2-acetylaminofluorene (2-AAF) treatment combined with partial hepatectomy (PH). EZP treated 2-AAF/PH-induced liver injury by the therapeutic and prophylactic administration. After the administration of EZP, the activities of aspartic transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AKP), and gamma-glutamyl transpeptidase (γ-GT) were decreased, followed by the decreased levels of hepatocyte apoptosis and caspase-3 expression. However, the secretion of albumin, liver weight, and index of liver weight were elevated. Microscopic examination showed that EZP restored pathological liver injury. Meanwhile, Rheb and mammalian target of rapamycin (mTOR) activation were suppressed, and tuberous sclerosis complex (TSC) expression was elevated in liver tissues induced by 2-AAF/PHx and accompanied with lower-expression of Bax, Notch1, p70S6K, and 4E-EIF and upregulated levels of Bcl-2 and Cyclin D. Hepatoprotective effect of EZP was possibly realized via inhibiting TSC/mTOR signaling pathway to suppress excessive apoptosis of hepatocyte.