Identification of Senkyunolide I as a novel modulator of hepatic steatosis and PPARα signaling in zebrafish and hamster models.

ETHNOPHARMACOLOGICAL RELEVANCE: Non-alcoholic fatty liver disease (NAFLD) is the leading cause of liver-related morbidity and mortality, with hepatic steatosis being the hallmark symptom. Salvia miltiorrhiza Bunge (Smil, Dan-Shen) and Ligusticum striatum DC (Lstr, Chuan-Xiong) are commonly used to treat cardiovascular diseases and have the potential to regulate lipid metabolism. However, whether Smil/Lstr combo can be used to treat NAFLD and the mechanisms underlying its lipid-regulating properties remain unclear. PURPOSE: To assess the feasibility and reliability of a short-term high-fat diet (HFD) induced zebrafish model for evaluating hepatic steatosis phenotype and to investigate the liver lipid-lowering effects of Smil/Lstr, as well as its active components. METHODS: The phenotypic alterations of liver and multiple other organ systems were examined in the HFD zebrafish model using fluorescence imaging and histochemistry. The liver-specific lipid-lowering effects of Smil/Lstr combo were evaluated endogenously. The active molecules and functional mechanisms were further explored in zebrafish, human hepatocytes, and hamster models. RESULTS: In 5-day HFD zebrafish, significant lipid accumulation was detected in the blood vessels and the liver, as evidenced by increased staining with Oil Red O and fluorescent lipid probes. Hepatic hypertrophy was observed in the model, along with macrovesicular steatosis. Smil/Lstr combo administration effectively restored the lipid profile and alleviated hepatic hypertrophy in the HFD zebrafish. In oleic-acid stimulated hepatocytes, Smil/Lstr combo markedly reduced lipid accumulation and cell damage. Subsequently, based on zebrafish phenotypic screening, the natural phthalide senkyunolide I (SEI) was identified as a major molecule mediating the lipid-lowering activities of Smil/Lstr combo in the liver. Moreover, SEI upregulated the expression of the lipid metabolism regulator PPARα and downregulated fatty acid translocase CD36, while a PPARα antagonist sufficiently blocked the regulatory effect of SEI on hepatic steatosis. Finally, the roles of SEI on hepatic lipid accumulation and PPARα signaling were further verified in the hamster model. CONCLUSIONS: We proposed a zebrafish-based screening strategy for modulators of hepatic steatosis and discovered the regulatory roles of Smil/Lstr combo and its component SEI on liver lipid accumulation and PPARα signaling, suggesting their potential value as novel candidates for NAFLD treatment.

Chronic binge alcohol mediated hepatic metabolic adaptations in SIV-infected female rhesus macaques.

AIMS: As the interactions of alcohol and HIV/SIV infection and their impact on liver metabolic homeostasis remain to be fully elucidated, this study aimed to determine alcohol-mediated hepatic adaptations of metabolic pathways in SIV/ART-treated female rhesus macaques fed a nutritionally balanced diet. METHODS: Macaques were administered chronic binge alcohol (CBA; 13-14 g ethanol/kg/week for 14.5 months; n = 7) or vehicle (VEH; n = 8) for 14.5 months. Livers were excised following an overnight fast. Gene and protein expression, enzymatic activity, and lipid content were determined using frozen tissue and histological staining was performed using paraffin-embedded tissue. RESULTS: CBA/SIV macaques showed increased hepatic protein expression of electron transport Complex III and increased gene expression of glycolytic (phosphofructokinase and aldolase) and gluconeogenic (pyruvate carboxylase) enzymes and of genes involved in lipid turnover homeostasis (perilipin 1, peroxisome proliferator-activated receptor gamma, carbohydrate responsive binding protein, and acetyl-CoA carboxylase B) as compared to that of livers from the VEH/SIV group. Plasma triglyceride concentration had a significant positive association with liver triglyceride content in the CBA/SIV group. CONCLUSIONS: These results reflect CBA-associated alterations in expression of proteins and genes involved in glucose and lipid metabolism homeostasis without significant evidence of steatosis or dysglycemia. Whether these changes predispose to greater liver pathology upon consumption of a high fat/high sugar diet that is more aligned with dietary intake of PWH and/or exposure to additional environmental factors warrants further investigation.

Regulatory mechanism of Sarmentosin and Quercetin on lipid accumulation in primary hepatocyte of GIFT tilapia (Oreochromis niloticus) with fatty liver.

Sarmentosin (SA) and Quercetin (QC) are two active components of Sedum Sarmentosum Bunge, which is a traditional Chinese herbal medicine. This study aimed to investigate the role and regulatory mechanism of SA and QC in fatty liver of Genetic Improvement of Farmed Tilapia (GIFT) tilapia. GIFT tilapia were randomly divided into two groups with three replicates per treatment (30 fish in each replicate): normal diet group (average weight 3.51±0.31 g) and high-fat diet group (average weight 3.44±0.09 g). After 8 weeks feeding trial, growth index, lipid deposition, and biochemical indexes were measured. Lipid deposition, and lipid and inflammation-related gene expression were detected in a primary hepatocyte model of fatty liver of GIFT tilapia treated with SA or QC. Our results showed that high-fat diet caused lipid deposition and peroxidative damage in the liver of GIFT tilapia. The cell counting kit-8 assay results indicated that 10 µM SA and 10 µM of QC both had the least effect on hepatocyte proliferation. Moreover, both 10 µM of SA and 10 µM of QC showed lipolytic effects and inhibited the expression of lipid-related genes (FAS, Leptin, SREBP-1c, and SREBP2) in fatty liver cells. Interestingly, QC induced autophagosome-like subcellular structure and increased the expression of IL-8 in fatty liver cells. In conclusion, this study confirmed that SA and QC improved fatty liver caused by high-fat diet, providing a novel therapeutic approach for fatty liver of GIFT tilapia.

Exposure to Succinate Leads to Steatosis in Non-Obese Non-Alcoholic Fatty Liver Disease by Inhibiting AMPK/PPARα/FGF21-Dependent Fatty Acid Oxidation.

Succinate is an important metabolite and a critical chemical with diverse applications in the food, pharmaceutical, and agriculture industries. Recent studies have demonstrated several protective or detrimental functions of succinate in diseases; however, the effect of succinate on lipid metabolism is still unclear. Here, we identified a role of succinate in nonobese nonalcoholic fatty liver disease (NAFLD). Specifically, the level of succinate is increased in the livers and serum of mice with hepatic steatosis. The administration of succinate promotes triglyceride (TG) deposition and hepatic steatosis by suppressing fatty acid oxidation (FAO) in nonobese NAFLD mouse models. RNA-Seq revealed that succinate suppressed fibroblast growth factor 21 (FGF21) expression. Then, the restoration of FGF21 was sufficient to alleviate hepatic steatosis and FAO inhibition induced by succinate treatment in vitro and in vivo. Furthermore, the inhibition of FGF21 expression and FAO mediated by succinate was dependent on the AMPK/PPARα axis. This study provides evidence linking succinate exposure to abnormal hepatic lipid metabolism and the progression of nonobese NAFLD.

A Study of Small Intestinal Epigenomic Changes Induced by Royal Jelly.

This study explores the impact of royal jelly (RJ) on small intestinal epigenomic changes. RJ, produced by honeybees, is known for its effects on metabolic diseases. The hypothesis is that RJ induces epigenomic modifications in small intestinal epithelial cells, affecting gene expression and contributing to metabolic health. Male db/m and db/db mice were used to examine RJ's effects through mRNA sequencing and CUT&Tag methods. This study focused on histone modifications and gene expression changes, with statistical significance set at p < 0.05. RJ administration improved insulin sensitivity and lipid metabolism without affecting body weight. GO and KEGG pathway analyses showed significant enrichment in metabolic processes, cellular components, and molecular functions. RJ altered histone modifications, increasing H3K27me3 and decreasing H3K23Ac in genes associated with the G2M checkpoint. These genes, including Smc2, Mcm3, Ccnd1, Rasal2, Mcm6, and Mad2l1, are linked to cancer progression and metabolic regulation. RJ induces beneficial epigenomic changes in small intestinal epithelial cells, improving metabolic health and reducing cancer-associated gene expression. These findings highlight RJ's potential as a therapeutic agent for metabolic disorders. Further research is needed to fully understand the mechanisms behind these effects and their implications for human health.

Peri-Tumoural Lipid Composition and Hypoxia for Early Immune Response to Neoadjuvant Chemotherapy in Breast Cancer.

The deregulation of monounsaturated, polyunsaturated, and saturated fatty acids (MUFAs, PUFAs, SFAs) from de novo synthesis and hypoxia are central metabolic features of breast tumour. Early response markers for neoadjuvant chemotherapy (NACT) are critical for stratified treatment for patients with breast cancer, and restoration of lipid metabolism and normoxia might precede observable structural change. In this study, we hypothesised that peri-tumoural lipid composition and hypoxia might be predictive and early response markers in patients with breast cancer undergoing NACT. Female patients with breast cancer were scanned on a 3T clinical MRI scanner at baseline and Cycle1, with acquisition of lipid composition maps of MUFAs, PUFAs, and SFAs, and hypoxia maps of effective transverse relaxation rate R2*. The percentage change in lipid composition and hypoxia at Cycle1 was calculated with reference to baseline. Tumour-associated macrophages were analysed based on immunostaining of CD163 from biopsy and resection, with the percentage change in the resected tumour calculated across the entire NACT. We found no significant difference in lipid composition and R2* between good and poor responders at baseline and Cycle1; however, the correlation between the percentage change in MUFAs and PUFAs against CD163 suggested the modulation in lipids with altered immune response might support the development of targeted therapies.

Targeting CD36-Mediated Lipid Metabolism by Selective Inhibitor-Augmented Antitumor Immune Responses in Oral Cancer.

The fatty acid receptor CD36 is expressed on various malignant cells and is suggested to contribute to tumor progression. CD36 is also expressed by several immune cells and involved in immune responses and may be a potential target in cancer immunotherapy. In this study, we investigated whether the selective inhibition of CD36 can inhibit tumor progression and facilitate an antitumor immune response in oral squamous carcinoma cells (OSCCs). We assessed the effects of sulfosuccinimidyl oleate sodium (SSO), a CD36 inhibitor, on the proliferation apoptosis and alteration in tumor cell surface expression levels of immune accessory molecules in vitro. We also assessed whether SSO-treated OSCCs could promote a T cell response via a Mixed Lymphocyte Reaction (MLR) assay. We also investigated the direct antitumor effects and immunomodulatory effects of SSO using a mouse oral cancer OSCC model. SSO treatment significantly inhibited OSCC proliferation, increased apoptotic cell death, and upregulated the cell surface expression of several immune accessory molecules, including CD83, MHC-Class II, and PD-L1. SSO-treated OSCCs augmented T cell proliferation following MLR. In vivo SSO administration significantly attenuated mouse tumor growth with an increased proportion of immune cells, including CD4+ T, CD8+ T, and dendritic cells; it also decreased the proportion of immune suppressive cells, such as myeloid-derived suppressor and regulatory T cells. These results suggest that the selective inhibition of CD36 can induce direct and indirect antitumor effects by facilitating host antitumor immune responses in OSCCs.

Oxidative Stress and Annexin A2 Differential Expression in Free Fatty Acids-Induced Non-Alcoholic Fatty Liver Disease in HepG2 Cells.

Non-alcoholic fatty liver disease (NAFLD) is a rising global burden, affecting one in four adults. Despite the increasing prevalence of NAFLD, the exact cellular and molecular mechanisms remain unclear, and effective therapeutic strategies are still limited. In vitro models of NAFLD are critical to understanding the pathogenesis and searching for effective therapies; thus, we evaluated the effects of free fatty acids (FFAs) on NAFLD hallmarks and their association with the modulation of Annexin A2 (ANXA2) and Keratin 17 (KRT17) in HepG2 cells. Our results show that oleic and palmitic acids can differentially induce intracellular lipid accumulation, cell death, and promote oxidative stress by increasing lipid peroxidation, protein carbonylation, and antioxidant defense depletion. Moreover, a markedly increased expression of inflammatory cytokines demonstrated the activation of inflammation pathways associated with lipotoxicity and oxidative stress. ANXA2 overexpression and KRT17 nuclear translocation were also observed, supporting the role of both molecules in the progression of liver disease. Taken together, these data provide insights into the interplay between ANXA2 and KRT17 in NAFLD, paving the way for understanding molecular mechanisms involved with the disease and developing new therapeutic strategies.

Natural Products and Altered Metabolism in Cancer: Therapeutic Targets and Mechanisms of Action.

Cancer is characterized by uncontrolled cell proliferation and the dysregulation of numerous biological functions, including metabolism. Because of the potential implications of targeted therapies, the metabolic alterations seen in cancer cells, such as the Warburg effect and disruptions in lipid and amino acid metabolism, have gained attention in cancer research. In this review, we delve into recent research examining the influence of natural products on altered cancer metabolism. Natural products were selected based on their ability to target cancer's altered metabolism. We identified the targets and explored the mechanisms of action of these natural products in influencing cellular energetics. Studies discussed in this review provide a solid ground for researchers to consider natural products in cancer treatment alone and in combination with conventional anticancer therapies.

Clerodendranthus spicatus (Thunb.) Water Extracts Reduce Lipid Accumulation and Oxidative Stress in the Caenorhabditis elegans.

Clerodendranthus spicatus (Thunb.) (Kidney tea) is a very distinctive ethnic herbal medicine in China. Its leaves are widely used as a healthy tea. Many previous studies have demonstrated its various longevity-promoting effects; however, the safety and specific health-promoting effects of Clerodendranthus spicatus (C. spicatus) as a dietary supplement remain unclear. In order to understand the effect of C. spicatus on the longevity of Caenorhabditis elegans (C. elegans), we evaluated its role in C. elegans; C. spicatus water extracts (CSw) were analyzed for the major components and the effects on C. elegans were investigated from physiological and biochemical to molecular levels; CSw contain significant phenolic components (primarily rosmarinic acid and eugenolinic acid) and flavonoids (primarily quercetin and isorhamnetin) and can increase the lifespan of C. elegans. Further investigations showed that CSw modulate stress resistance and lipid metabolism through influencing DAF-16/FoxO (DAF-16), Heat shock factor 1 (HSF-1), and Nuclear Hormone Receptor-49 (NHR-49) signalling pathways; CSw can improve the antioxidant and hypolipidemic activity of C. elegans and prolong the lifespan of C. elegans (with the best effect at low concentrations). Therefore, the recommended daily use of C. spicatus should be considered when consuming it as a healthy tea on a daily basis.

8-Prenylgenistein Isoflavone in Cheonggukjang Acts as a Novel AMPK Activator Attenuating Hepatic Steatosis by Enhancing the SIRT1-Mediated Pathway.

8-Prenylgenistein (8PG), a genistein derivative, is present in fermented soybeans (Glycine max), including cheonggukjang (CGJ), and exhibits osteoprotective, osteogenic, and antiadipogenic properties. However, the hepatoprotective effects of 8PG and its underlying molecular mechanisms remain largely unexplored. Here, we identified the high binding affinity of 8PG with AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1), which acts as a potent AMPK activator that counteracts hepatic steatosis. Notably, 8PG exhibited better pharmacokinetics with greater absorption and higher plasma binding than the positive controls for the target proteins. Moreover, 8PG exerted non-carcinogenic activity in rats and significantly increased AMPK phosphorylation. Compound C, an AMPK inhibitor, did not antagonize 8PG-activated AMPK in HepG2 cells. 8PG significantly attenuated palmitate-induced lipid accumulation and enhanced phosphorylated AMPK and its downstream target, acetyl-CoA carboxylase. Further, 8PG activated nuclear SIRT1 at the protein level, which promoted fatty acid oxidation in palmitate-treated HepG2 cells. Overall, 8PG acts as a potent AMPK activator, further attenuating hepatic steatosis via the SIRT1-mediated pathway and providing new avenues for dietary interventions to treat metabolic dysfunction-associated steatotic liver disease (MASLD).

Spatial regulation of NMN supplementation on brain lipid metabolism upon subacute and sub-chronic PM exposure in C57BL/6 mice.

BACKGROUND: Atmospheric particulate matter (PM) exposure-induced neuroinflammation is critical in mediating nervous system impairment. However, effective intervention is yet to be developed. RESULTS: In this study, we examine the effect of ß-nicotinamide mononucleotide (NMN) supplementation on nervous system damage upon PM exposure and the mechanism of spatial regulation of lipid metabolism. 120 C57BL/6 male mice were exposed to real ambient PM for 11 days (subacute) or 16 weeks (sub-chronic). NMN supplementation boosted the level of nicotinamide adenine dinucleotide (NAD+) in the mouse brain by 2.04 times. This augmentation effectively reduced neuroinflammation, as evidenced by a marked decrease in activated microglia levels across various brain regions, ranging from 29.29 to 85.96%. Whole brain lipidomics analysis revealed that NMN intervention resulted in an less increased levels of ceramide (Cer) and lysophospholipid in the brain following subacute PM exposure, and reversed triglyceride (TG) and glycerophospholipids (GP) following sub-chronic PM exposure, which conferred mice with anti-neuroinflammation response, improved immune function, and enhanced membrane stability. In addition, we demonstrated that the hippocampus and hypothalamus might be the most sensitive brain regions in response to PM exposure and NMN supplementation. Particularly, the alteration of TG (60:10, 56:2, 60:7), diacylglycerol (DG, 42:6), and lysophosphatidylcholine (LPC, 18:3) are the most profound, which correlated with the changes in functional annotation and perturbation of pathways including oxidative stress, inflammation, and membrane instability unveiled by spatial transcriptomic analysis. CONCLUSIONS: This study demonstrates that NMN intervention effectively reduces neuroinflammation in the hippocampus and hypothalamus after PM exposure by modulating spatial lipid metabolism. Strategies targeting the improvement of lipid homeostasis may provide significant protection against brain injury associated with air pollutant exposure.

Combinatorial targeting of glutamine metabolism and lysosomal-based lipid metabolism effectively suppresses glioblastoma.

Antipsychotic drugs have been shown to have antitumor effects but have had limited potency in the clinic. Here, we unveil that pimozide inhibits lysosome hydrolytic function to suppress fatty acid and cholesterol release in glioblastoma (GBM), the most lethal brain tumor. Unexpectedly, GBM develops resistance to pimozide by boosting glutamine consumption and lipogenesis. These elevations are driven by SREBP-1, which we find upregulates the expression of ASCT2, a key glutamine transporter. Glutamine, in turn, intensifies SREBP-1 activation through the release of ammonia, creating a feedforward loop that amplifies both glutamine metabolism and lipid synthesis, leading to drug resistance. Disrupting this loop via pharmacological targeting of ASCT2 or glutaminase, in combination with pimozide, induces remarkable mitochondrial damage and oxidative stress, leading to GBM cell death in vitro and in vivo. Our findings underscore the promising therapeutic potential of effectively targeting GBM by combining glutamine metabolism inhibition with lysosome suppression.

Macrophage Membrane Spontaneously Encapsulated Cyclodextrin-Based Nanomedicines for Improving Lipid Metabolism and Inflammation in Atherosclerosis.

Atherosclerosis is a persistent inflammatory condition of the blood vessels associated with abnormalities in lipid metabolism. Development of biomimetic nanoplatforms provides an effective strategy. Herein, inspired by the peptide CLIKKPF spontaneously coupling to phosphatidylserine (PS) on the inner leaflet of cell membranes specifically, MM@NPs were constructed by macrophage membrane spontaneous encapsulation of cyclodextrin-based nanoparticles modified with the peptide CLIKKPF and loaded with the hydrophobic compound resveratrol. MM@NPs could be specifically phagocytized by the activated endothelium with the overexpressed VCAM-1 for enhancing target delivery into the pathological lesion. Additionally, for the ApoE-/- mice, MM@NPs provide comprehensive treatment efficiency in reducing oxidant stress, alleviating the inherent inflammation, and decreasing cholesterol deposition, subsequently resulting in the atherosclerotic plaque regression. Therefore, MM@NPs could be one possible candidate for improving lipid metabolism and inflammation in atherosclerosis.

Mechanisms insights into bisphenol S-induced oxidative stress, lipid metabolism disruption, and autophagy dysfunction in freshwater crayfish.

Bisphenol S (BPS) is widely used in plastic products, food packaging, electronic products, and other applications. In recent years, BPS emissions have increasingly impacted aquatic ecosystems. The effects of BPS exposure on aquatic animal health have been documented; however, our understanding of its toxicology remains limited. This study aimed to explore the mechanisms of lipid metabolism disorders, oxidative stress, and autophagy dysfunction induced in freshwater crayfish (Procambarus clarkii) by exposure to different concentrations of BPS (0 µg/L, 1 µg/L, 10 µg/L, and 100 µg/L) over 14 d. The results indicated that BPS exposure led to oxidative stress by inducing elevated levels of reactive oxygen species (ROS) and inhibiting the activity of antioxidant-related enzymes. Additionally, BPS exposure led to increased lipid content in the serum and hepatopancreas, which was associated with elevated lipid-related enzyme activity and increased expression of related genes. Furthermore, BPS exposure decreased levels of phosphatidylcholine (PC) and phosphatidylinositol (PI), disrupted glycerophospholipid (GPI) metabolism, and caused lipid deposition in the hepatopancreatic. These phenomena may have occurred because BPS exposure reduced the transport of fatty acids and led to hepatopancreatic lipid deposition by inhibiting the transport and synthesis of PC and PI in the hepatopancreas, thereby inhibiting the PI3K-AMPK pathway. In conclusion, BPS exposure induced oxidative stress, promoted lipid accumulation, and led to autophagy dysfunction in the hepatopancreas of freshwater crayfish. Collectively, our findings provide the first evidence that environmentally relevant levels of BPS exposure can induce hepatopancreatic lipid deposition through multiple pathways, raising concerns about the potential population-level harm of BPS and other bisphenol analogues.

OsPLDα1 mediates cadmium stress response in rice by regulating reactive oxygen species accumulation and lipid remodeling.

Lipid remodeling is crucial for various cellular activities and the stress tolerance of plants; however, little is known about the lipid dynamics induced by the heavy metal cadmium (Cd). In this study, we investigated the phospholipid profiles in rice (Oryza sativa) under Cd exposure. We observed a significant decline in the total amounts of phosphatidylcholine and phosphatidylserine, contrasted with an elevation in phosphatidic acid (PA) due to Cd stress. Additionally, Cd stress prompted the activation of phospholipase D (PLD) and induced the expression of PLDα1. OsPLDα1 knockout mutants (Ospldα1) showed increased sensitivity to Cd, characterized by a heightened accumulation of hydrogen peroxide in roots and diminished PA production following Cd treatment. Conversely, PLDα1-overexpressing (OsPLDα1-OE) lines demonstrated enhanced tolerance to Cd, with suppressed transcription of the respiratory burst oxidase homolog (Rboh) genes. The transcription levels of genes associated with Cd uptake and transport were accordingly modulated in Ospldα1 and OsPLDα1-OE plants relative to the wild-type. Taken together, our findings underscore the pivotal role of OsPLDα1 in conferring tolerance to Cd by modulating reactive oxygen species homeostasis and lipid remodeling in rice.

Farrerol alleviates insulin resistance and hepatic steatosis of metabolic associated fatty liver disease by targeting PTPN1.

Metabolic associated fatty liver disease (MAFLD) is the most common chronic liver disease worldwide, characterized by excess lipid deposition. Insulin resistance (IR) serves as a fundamental pathogenic factor in MAFLD. However, currently, there are no approved specific agents for its treatment. Farrerol, a novel compound with antioxidant and anti-inflammatory effects, has garnered significant attention in recent years due to its hepatoprotective properties. Despite this, the precise underlying mechanisms of action remain unclear. In this study, a network pharmacology approach predicted protein tyrosine phosphatase non-receptor type 1 (PTPN1) as a potential target for farrerol's action in the liver. Subsequently, the administration of farrerol improved insulin sensitivity and glucose tolerance in MAFLD mice. Furthermore, farrerol alleviated lipid accumulation by binding to PTPN1 and reducing the dephosphorylation of the insulin receptor (INSR) in HepG2 cells and MAFLD mice. Thus, the phosphoinositide 3-kinase/serine/threonine-protein kinases (PI3K/AKT) signalling pathway was active, leading to downstream protein reduction. Overall, the study demonstrates that farrerol alleviates insulin resistance and hepatic steatosis of MAFLD by targeting PTPN1.

[Mechanism of berberine in improving adipocytic IR by mediating BMAL1:CLOCK complex and regulating glucose and lipid metabolism].

To explore the action mechanism of berberine in improving adipocytic insulin resistance(IR) by mediating brain and muscle arnt-like 1(BMAL1): circadian locomotor output cycles kaput(CLOCK) complex and regulating glucose and lipid metabolism. After the IR-3T3-L1 adipocyte model was established by dexamethasone induction for 96 h, 0.5, 1, 5, 10, and 20 µmol·L~(-1) berberine was administered for 24 h. The glucose oxidase method and cell counting kit-8(CCK-8) were used to detect extracellular glucose content and cell viability, respectively. The triglyceride(TG) and glycerol contents were detected by enzyme colorimetry. Oil red O staining was used to detect lipid droplets, and fluorescence staining was used to detect Ca~(2+), mitochondrial structure, and reactive oxygen species(ROS). Adiponectin(ADPN), BMAL1, CLOCK, hormone-sensitive triglyceride lipase(HSL), carbohydrate-response element-binding protein(ChREBP), sterol regulatory element-binding protein 1C(SREBP-1C), peroxisome proliferator-activated receptor γ coactivator 1α(PGC1α), carnitine palmitoyl transferase 1α(CPT1α), and peroxisome proliferator-activated receptor α(PPARα) were detected by Western blot(WB). Moreover, the nuclear localization of BMAL1 was detected by immunofluorescence. In addition, 20 µmol·L~(-1) CLK8 inhibitor was added to detect glucose consumption and BMAL1/ChREBP/PPARα protein. The results showed that berberine increased glucose consumption in IR-3T3-L1 adipocytes without affecting cell viability and reduced TG content. In addition, 5 µmol·L~(-1) berberine increased glycerol content and reduced lipid droplet accumulation due to enhanced lipolysis, while 10 µmol·L~(-1) berberine did not affect glycerol content, and fewer lipid droplets were observed due to enhanced lipolysis and glycerol utilization. Berberine improved mitochondrial function by reducing intracellular Ca~(2+) and ROS in IR-3T3-L1 adipocytes and upregulated PGC1α to improve the mitochondrial structure. The results also showed that berberine elevated ADPN to increase the insulin sensitivity of IR-3T3-L1 adipocytes, upregulated peripheral rhythm-related proteins BMAL1 and CLOCK, and strengthened the nuclear localization of BMAL1. In addition, berberine increased key lipolysis protein and lipid oxidation rate-limiting enzyme CPT1α and downregulated the key protein of TG synthesis, SREBP-1C. Moreover, ChREBP and PPARα in IR-3T3-L1 adipocytes were upregula-ted. All the above results suggested that berberine may transform glucose into lipids to enhance the hypoglycemic effect. By considering that CLK8 specifically inhibited the CLOCK acylation to modify BMAL1 and form complex, the results showed that the addition of CLK8 to the berberine group reduced glucose consumption, which suggested that berberine upregulated the formation of BMAL1:CLOCK complex to improve glucose metabolism. The addition of CLK8 to the berberine group upregulated BMAL1 but downregulated ChREBP and PPARα, which suggested that berberine mediated BMAL1:CLOCK complex for the regulation of glucose and lipid metabo-lism to improve adipocytic IR.

Zhimu-Huangbai herb-pair ameliorates hepatic steatosis in mice by regulating IRE1α/XBP1s pathway to inhibit SREBP-1c.

BACKGROUND: Currently, there is a lack of validated pharmacological interventions for non-alcoholic fatty liver disease (NAFLD), which is characterized by the accumulation of hepatic triglyceride. Zhimu-Huangbai (ZH) herb-pair is a traditional Chinese medicine that regulates glucose and lipid metabolism disorders. However, the precise mechanisms underlying the preventive effects of hepatic triglyceride induced by high-fat diet (HFD) remain elusive. PURPOSE: The study aimed to examine the impact of ZH herb-pair on NAFLD in mice and explore the underlying mechanisms, particularly its effects on endoplasmic reticulum (ER) stress and lipid metabolism. METHODS: NAFLD was induced in mice using HFD, and the treated mice were orally administered ZH, metformin (Glucophage) or lovastatin. The lipid metabolism factors, ER stress markers, and the unfolded protein response (UPR) branch factors were measured using immunohistochemistry, western blotting or qRT-PCR. Co-Immunoprecipitation (CoIP) was performed to reveal the connection between SCAP and SREBP-1c. Tunicamycin (TM) and plasmid delivery were used to induce acute ER stress or crease XBP1 gain function models. The main compounds in ZH binding to IRE1α protein were studied by molecular docking and cellular thermal shift assay (CETSA). RESULTS: Treatment with ZH significantly ameliorated hepatic steatosis and reduced lipid synthesis process mainly inhibiting the expression of mature active form of SREBP-1c through relieving ER stress. The expression of IRE1α and XBP1s was inhibited after treatment with ZH. In addition, ZH improved the fatty liver phenotype caused by XBP1 overexpression via decreasing srebp1c transcription. In vitro experimental results suggested that the main compounds in ZH decreased cellular TG contents. Mechanistically, ZH targeted IRE1α and inhibited XBP1s mRNA expression to relieve ER stress and inhibit SREBP-1c production. CONCLUSIONS: ZH herb-pair can protect against NAFLD by reducing the expression of SREBP-1c, in part, via regulating IRE1α/XBP1s pathway.

Mechanism of Obesity-Related Lipotoxicity and Clinical Perspective.

The link between cellular exposure to fatty acid species and toxicity phenotypes remains poorly understood. However, structural characterization and functional profiling of human plasma free fatty acids (FFAs) analysis has revealed that FFAs are located either in the toxic cluster or in the cluster that is transcriptionally responsive to lipotoxic stress and creates genetic risk factors. Genome-wide short hairpin RNA screen has identified more than 350 genes modulating lipotoxicity. Hypertrophic adipocytes in obese adipose are both unable to expand further to store excess lipids in the diet and are resistant to the antilipolytic action of insulin. In addition to lipolysis, the inability of packaging the excess lipids into lipid droplets causes circulating fatty acids to reach toxic levels in non-adipose tissues. Deleterious effects of accumulated lipid in non-adipose tissues are known as lipotoxicity. Although triglycerides serve a storage function for long-chain non-esterified fatty acid and their products such as ceramide and diacylglycerols (DAGs), overloading of palmitic acid fraction of saturated fatty acids (SFAs) raises ceramide levels. The excess DAG and ceramide load create harmful effects on multiple organs and systems, inducing chronic inflammation in obesity. Thus, lipotoxic inflammation results in ß cells death and pancreatic islets dysfunction. Endoplasmic reticulum stress stimuli induce lipolysis by activating cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) and extracellular signal-regulated kinase (Erk) 1/2 signaling in adipocytes. However, palmitic acid-induced endoplasmic reticulum stress-c-Jun N-terminal kinase (JNK)-autophagy axis in hypertrophic adipocytes is a pro-survival mechanism against endoplasmic reticulum stress and cell death induced by SFAs. Endoplasmic reticulum-localized acyl-coenzyme A (CoA): glycerol-3-phosphate acyltransferase (GPAT) enzymes are mediators of lipotoxicity, and inhibiting these enzymes has therapeutic potential for lipotoxicity. Lipotoxicity increases the number of autophagosomes, which engulf palmitic acid, and thus suppress the autophagic turnover. Fatty acid desaturation promotes palmitate detoxification and storages into triglycerides. As therapeutic targets of glucolipotoxicity, in addition to caloric restriction and exercise, there are four different pharmacological approaches, which consist of metformin, glucagon-like peptide 1 (GLP-1) receptor agonists, peroxisome proliferator-activated receptor-gamma (PPARγ) ligands thiazolidinediones, and chaperones are still used in clinical practice. Furthermore, induction of the brown fat-like phenotype with the mixture of eicosapentanoic acid and docosahexaenoic acid appears as a potential therapeutic application for treatment of lipotoxicity.