The Roles of mTOR Complexes in Lipid Metabolism

Valproic acid targets IDH1 mutants through alteration of lipid metabolism

Histone deacetylases (HDACs) have a wide range of targets and can rewire both the chromatin and lipidome of cancer cells. In this study, we show that valproic acid (VPA), a brain penetrant anti-seizure medication and histone deacetylase inhibitor, inhibits the growth of IDH1 mutant tumors in vivo and in vitro, with at least some selectivity over IDH1 wild-type tumors. Surprisingly, genes upregulated by VPA showed no enhanced chromatin accessibility at the promoter, but there was a correlation between VPA-downregulated genes and diminished promoter chromatin accessibility. VPA inhibited the transcription of lipogenic genes and these lipogenic genes showed significant decreases in promoter chromatin accessibility only in the IDH1 MT glioma cell lines tested. VPA inhibited the mTOR pathway and a key lipogenic gene, fatty acid synthase (FASN). Both VPA and a selective FASN inhibitor TVB-2640 rewired the lipidome and promoted apoptosis in an IDH1 MT but not in an IDH1 WT glioma cell line. We further find that HDACs are involved in the regulation of lipogenic genes and HDAC6 is particularly important for the regulation of FASN in IDH1 MT glioma. Finally, we show that FASN knockdown alone and VPA in combination with FASN knockdown significantly improved the survival of mice in an IDH1 MT primary orthotopic xenograft model in vivo. We conclude that targeting fatty acid metabolism through HDAC inhibition and/or FASN inhibition may be a novel therapeutic opportunity in IDH1 mutant gliomas.

Sestrin2 knockout exacerbates high-fat diet induced metabolic disorders and complications in female mice

BACKGROUND

Obesity and its associated complications raise significant public concern, revealing gender disparities in the susceptibility to metabolic disorders, with females often displaying greater resistance to obesity-related metabolic disorder than males. Sestrin2 is a crucial protein involved in metabolism and energy balance. This study seeks to explore whether Sesn2 knockout (KO) exacerbates high-fat diet (HFD) induced obesity in female mice.

METHODS

Female mice with wild-type (WT) and Sesn2 KO were subjected to a 12-week regimen of normal diet or HFD. Using a Body Composition Analyzer, body composition was gauged. Biochemical assays encompassed glucose, lipid, and liver function measurements, alongside 24-hour urine albumin excretion. Echocardiographic evaluation assessed cardiac function. Histopathological analysis of key metabolic tissues (liver, kidney, and heart tissues) were conducted. Western blotting or qRT-PCR evaluated key proteins and genes linked to inflammation, mitochondrial, and lipid metabolism in adipose tissues.

RESULTS

In comparison to mice fed a regular diet, those on a HFD exhibited significant increases in body weight and fat mass. Notably, Sesn2 KO further aggravated obesity, showcasing the most pronounced metabolic anomalies: elevated body weight, fat mass, impaired glucose tolerance, and insulin sensitivity, alongside heightened levels of free fatty acids and triglycerides. Additionally, KO-HFD mice displayed exacerbated multi-tissue impairments, including elevated hepatic enzymes, increased urinary albumin excretion, compromised cardiac function, and accumulation of lipids in the liver, kidney, and heart. Moreover, adipose tissue showcased altered lipid dynamics and function, characterized by enhanced triglyceride breakdown and modified adipokine levels. Browning was diminished, along with decreased Pgc1α and Sirt1 in KO-HFD mice.

CONCLUSION

Sesn2 KO exacerbates HFD-induced obesity and metabolic disorders in female mice. These findings underscore Sestrin2's novel role as a regulator of obesity in female mice.

mTORC2 knockdown mediates lipid metabolism to alleviate hyperlipidemic pancreatitis through PPARα

Hyperlipidemic pancreatitis (HP) is an inflammatory injury of the pancreas triggered by elevated serum triglyceride (TG) levels. The mechanistic target of rapamycin (mTOR) signaling pathway plays a crucial role in regulating lipid homeostasis and inflammation. This study aimed to investigate whether the activity of mTOR complex 2 (mTORC2) affects the progression of HP and its underlying mechanisms. In vivo, a high-fat diet and retrograde administration of sodium taurocholate were employed to establish the HP models in rats, with pancreatic tissue pathology evaluated. The expression of Rictor and peroxisome proliferator-activator receptor (PPAR) was examined. The serum levels of TG, fatty acid metabolites, inflammatory and lipid metabolism-related factors were determined. In vitro, pancreatic acinar cells (PACs) were exposed to palmitic acid and cholecystokinin-8. PAC apoptosis, pyroptosis, and ferroptosis were assessed. In the HP models, rats and PACs exhibited upregulated Rictor and downregulated PPARα, and Rictor knockdown promoted PPARα expression. In vivo, Rictor knockdown decreased the serum levels of TG, α-amylase, total cholesterol, low-density lipoprotein cholesterol, lactate dehydrogenase, and inflammatory factors, while increasing high-density lipoprotein cholesterol levels. Rictor knockdown increased ACOX1 and CPT1α and decreased SREBP-1, CD36, SCD1, ACLY, and ACACA. Rictor knockdown reduced damage to pancreatic tissue structure. In vitro, Rictor knockdown inhibited PAC apoptosis, pyroptosis, and ferroptosis. Treatment with the PPARα antagonist GW6471 abolished the beneficial effects of Rictor knockdown. Rictor/mTORC2 deficiency reduces serum TG levels, maintains lipid homeostasis, and suppresses inflammation by inhibiting PPARα expression. Weakening mTORC2 activity holds promise as a novel therapeutic strategy for HP.

From fasting to fat reshaping: exploring the molecular pathways of intermittent fasting-induced adipose tissue remodeling

Obesity, characterised by excessive fat accumulation, is a complex chronic condition that results from dysfunctional adipose tissue expansion due to prolonged calorie surplus. This leads to rapid adipocyte enlargement that exceeds the support capacity of the surrounding neurovascular network, resulting in increased hypoxia, inflammation, and insulin resistance. Intermittent fasting (IF), a dietary regimen that cycles between periods of fasting and eating, has emerged as an effective strategy to combat obesity and improve metabolic homeostasis by promoting healthy adipose tissue remodeling. However, the precise molecular and cellular mechanisms behind the metabolic improvements and remodeling of white adipose tissue (WAT) driven by IF remain elusive. This review aims to summarise and discuss the relationship between IF and adipose tissue remodeling and explore the potential mechanisms through which IF induces alterations in WAT. This includes several key structural changes, including angiogenesis and sympathetic innervation of WAT. We will also discuss the involvement of key signalling pathways, such as PI3K, SIRT, mTOR, and AMPK, which potentially play a crucial role in IF-mediated metabolic adaptations.

Perfluorooctanesulfonic acid exposure leads to downregulation of 3-hydroxy-3-methylglutaryl-CoA synthase 2 expression and upregulation of markers associated with intestinal carcinogenesis in mouse intestinal tissues

Perfluorooctanesulfonic acid (PFOS) is a widely recognized environment pollutant known for its high bioaccumulation potential and a long elimination half-life. Several studies have shown that PFOS can alter multiple biological pathways and negatively affect human health. Considering the direct exposure to the gastrointestinal (GI) tract to environmental pollutants, PFOS can potentially disrupt intestinal homeostasis. However, there is limited knowledge about the effect of PFOS exposure on normal intestinal tissues, and its contribution to GI-associated diseases remains to be determined. In this study, we examined the effect of PFOS exposure on the gene expression profile of intestinal tissues of C57BL/6 mice using RNAseq analysis. We found that PFOS exposure in drinking water significantly downregulates mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), a rate-limiting ketogenic enzyme, in intestinal tissues of mice. We found that diets containing the soluble fibers inulin and pectin, which are known to be protective against PFOS exposure, were ineffective in reversing the downregulation of HMGCS2 expression in vivo. Analysis of intestinal tissues also demonstrated that PFOS exposure leads to upregulation of proteins implicated in colorectal carcinogenesis, including β-catenin, c-MYC, mTOR and FASN. Consistent with the in vivo results, PFOS exposure leads to downregulation of HMGCS2 in mouse and human normal intestinal organoids in vitro. Furthermore, we show that shRNA-mediated knockdown of HMGCS2 in a human normal intestinal cell line resulted in increased cell proliferation and upregulation of key proliferation-associated proteins such as cyclin D, survivin, ERK1/2 and AKT, along with an increase in lipid accumulation. In summary, our results suggest that PFOS exposure may contribute to pathological changes in normal intestinal cells via downregulation of HMGCS2 expression and upregulation of pro-carcinogenic signaling pathways that may increase the risk of colorectal cancer development.

Effect of myristic acid supplementation on triglyceride synthesis and related genes in the pectoral muscles of broiler chickens

Fatty acids (FAs) can serve as energy for poultry, maintain normal cell structure and function, and support a healthy immune system. Although the addition of polyunsaturated fatty acids (PUFAs) to the diet has been extensively studied and reported, the mechanism of action of saturated fatty acids (SFAs) remains to be elucidated. We investigated the effect of 0.04% dietary myristic acid (MA) on slaughter performance, lipid components, tissue FAs, and the transcriptome profile in chickens. The results showed that dietary MA had no effect on slaughter performance (body weight, carcass weight, eviscerated weight, and pectoral muscle weight) (P > 0.05). Dietary MA enrichment increased MA (P < 0.001) and triglycerides (TGs) (P < 0.01) levels in the pectoral muscle. The levels of palmitic acid, linoleic acid (LA), arachidonic acid (AA), SFAs, monounsaturated fatty acids (MUFAs), and PUFAs were significantly higher (P < 0.01) in the MA supplementation group compared to the control group. However, there were no significant differences in the ratios of PUFA/SFA and n6/omega-3 (n3) between the two groups. The MA content was positively correlated with the contents of palmitic acid, LA, linolenic acid (ALA), n3, n6, SFAs, and unsaturated fatty acids (UFA). DHCR24, which is known to be involved in steroid metabolism and cholesterol biosynthesis pathways, was found to be a significantly lower in the MA supplementation group compared to the control group (P < 0.05, log2(fold change) = -0.85). Five overlapping co-expressed genes were identified at the intersection between the differential expressed genes and Weighted Gene Co‑expression Network Analysis-derived hub genes associated with MA phenotype, namely BHLHE40, MSL1, PLAGL1, SRSF4, and ENSGALG00000026875. For the TG phenotype, a total of 28 genes were identified, including CHKA, KLF5, TGIF1, etc. Both sets included the gene PLAGL1, which has a negative correlation with the levels of MA and TG. This study provides valuable information to further understand the regulation of gene expression patterns by dietary supplementation with MA and examines at the molecular level the phenotypic changes induced by supplementation with MA.

Alisol B regulates AMPK/mTOR/SREBPs via directly targeting VDAC1 to alleviate hyperlipidemia

BACKGROUND

The occurrence of hyperlipidemia is significantly influenced by lipid synthesis, which is regulated by sterol regulatory element binding proteins (SREBPs), thus the development of drugs that inhibit lipid synthesis has become a popular treatment strategy for hyperlipidemia. Alisol B (ALB), a triterpenoid compound extracted from Alisma, has been reported to ameliorate no-nalcoholic steatohepatitis (NASH) and slow obesity. However, the effect of ALB on hyperlipidemia and mechanism are unclear.

PURPOSE

To examine the therapeutic impact of ALB on hyperlipidemia whether it inhibits SREBPs to reduce lipid synthesis.

STUDY DESIGN

HepG2, HL7702 cells, and C57BL/6J mice were used to explore the effect of ALB on hyperlipidemia and the molecular mechanism in vivo and in vitro.

METHODS

Hyperlipidemia models were established using western diet (WD)-fed mice in vivo and oleic acid (OA)-induced hepatocytes in vitro. Western blot, real-time PCR and other biological methods verified that ALB regulated AMPK/mTOR/SREBPs to inhibit lipid synthesis. Cellular thermal shift assay (CETSA), molecular dynamics (MD), and ultrafiltration-LC/MS analysis were used to evaluate the binding of ALB to voltage-dependent anion channel protein-1 (VDAC1).

RESULTS

ALB decreased TC, TG, LDL-c, and increased HDL-c in blood, thereby ameliorating liver damage. Gene set enrichment analysis (GSEA) indicated that ALB inhibited the biosynthesis of cholesterol and fatty acids. Consistently, ALB inhibited the protein expression of n-SREBPs and downstream genes. Mechanistically, the impact of ALB on SREBPs was dependent on the regulation of AMPK/mTOR, thereby impeding the transportation of SREBPs from endoplasmic reticulum (ER) to golgi apparatus (GA). Further investigations indicated that the activation of AMPK by ALB was independent on classical upstream CAMKK2 and LKB1. Instead, ALB resulted in a decrease in ATP levels and an increase in the ratios of ADP/ATP and AMP/ATP. CETSA, MD, and ultrafiltration-LC/MS analysis indicated that ALB interacted with VDAC1. Molecular docking revealed that ALB directly bound to VDAC1 by forming hydrogen bonds at the amino acid sites S196 and H184 in the ATP-binding region. Importantly, the thermal stabilization of ALB on VDAC1 was compromised when VDAC1 was mutated at S196 and H184, suggesting that these amino acids played a crucial role in the interaction.

CONCLUSION

Our findings reveal that VDAC1 serves as the target of ALB, leading to the inhibition of lipid synthesis, presents potential target and candidate drugs for hyperlipidemia.

Leucine-Mediated SLC7A5 Promotes Milk Protein and Milk Fat Synthesis through mTOR Signaling Pathway in Goat Mammary Epithelial Cells

The SLC7A5 gene encodes a Na+ and pH-independent transporter protein that regulates cell growth by regulating the uptake of AA. This study, utilizing RNA-seq, aimed to explore the effect of SLC7A5 on the synthesis of milk proteins and fats in goat mammary epithelial cells (GMECs) through gene interference and overexpression techniques. The results demonstrated that the overexpression of SLC7A5 resulted in a significant increase in the expression of CSN1S1, SCD, CEBPB, ACACA, αS1-casein, p-S6K, and p-S6. The levels of p-S6K and p-S6 gradually increased as the AA/Leu stimulation time lengthened. The overexpression of SLC7A5 rescued the role of Torin1 in GMECs. In conclusion, SLC7A5 plays a crucial role in promoting the synthesis of milk proteins and milk fats through the mTOR signaling pathway in GMECs, providing a theoretical foundation for improving the quality of goat milk.

From NAFLD to NASH: Understanding the spectrum of non-alcoholic liver diseases and their consequences

Non-alcoholic fatty liver disease (NAFLD) has become one of the most frequent chronic liver diseases worldwide in recent decades. Metabolic diseases like excessive blood glucose, central obesity, dyslipidemia, hypertension, and liver function abnormalities cause NAFLD. NAFLD significantly increases the likelihood of liver cancer, heart disease, and mortality, making it a leading cause of liver transplants. Non-alcoholic steatohepatitis (NASH) is a more advanced form of the disease that causes scarring and inflammation of the liver over time and can ultimately result in cirrhosis and hepatocellular carcinoma. In this review, we briefly discuss NAFLD's pathogenic mechanisms, their progression into NASH and afterward to NASH-related cirrhosis. It also covers disease epidemiology, metabolic mechanisms, glucose and lipid metabolism in the liver, macrophage dysfunction, bile acid toxicity, and liver stellate cell stimulation. Additionally, we consider the contribution of intestinal microbiota, genetics, epigenetics, and ecological factors to fibrosis progression and hepatocellular carcinoma risk in NAFLD and NASH patients.

Molecular mechanisms of metabolic dysregulation in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM), one of the most serious complications of diabetes mellitus, has become recognized as a cardiometabolic disease. In normoxic conditions, the majority of the ATP production (>95%) required for heart beating comes from mitochondrial oxidative phosphorylation of fatty acids (FAs) and glucose, with the remaining portion coming from a variety of sources, including fructose, lactate, ketone bodies (KB) and branched chain amino acids (BCAA). Increased FA intake and decreased utilization of glucose and lactic acid were observed in the diabetic hearts of animal models and diabetic patients. Moreover, the polyol pathway is activated, and fructose metabolism is enhanced. The use of ketones as energy sources in human diabetic hearts also increases significantly. Furthermore, elevated BCAA levels and impaired BCAA metabolism were observed in the hearts of diabetic mice and patients. The shift in energy substrate preference in diabetic hearts results in increased oxygen consumption and impaired oxidative phosphorylation, leading to diabetic cardiomyopathy. However, the precise mechanisms by which impaired myocardial metabolic alterations result in diabetes mellitus cardiac disease are not fully understood. Therefore, this review focuses on the molecular mechanisms involved in alterations of myocardial energy metabolism. It not only adds more molecular targets for the diagnosis and treatment, but also provides an experimental foundation for screening novel therapeutic agents for diabetic cardiomyopathy.

Fetal growth restriction exhibits various mTOR signaling in different regions of mouse placentas with altered lipid metabolism

Fetal growth restriction (FGR) is a common complication of pregnancy and can have significant impact on obstetric and neonatal outcomes. Increasing evidence has shown that the inhibited mechanistic target of rapamycin (mTOR) signaling in placenta is associated with FGR. However, interpretation of existing research is limited due to inconsistent methodologies and varying understanding of the mechanism by which mTOR activity contributes to FGR. Hereby, we have demonstrated that different anatomic regions of human and mouse placentas exhibited different levels of mTOR activity in normal compared to FGR pregnancies. When using the rapamycin-induced FGR mouse model, we found that placentas of FGR pregnancies exhibited abnormal morphological changes and reduced mTOR activity in the decidual-junctional layer. Using transcriptomics and lipidomics, we revealed that lipid and energy metabolism was significantly disrupted in the placentas of FGR mice. Finally, we demonstrated that maternal physical exercise during gestation in our FGR mouse model was associated with increased fetal and placental weight as well as increased placental mTOR activity and lipid metabolism. Collectively, our data indicate that the inhibited placental mTOR signaling contributes to FGR with altered lipid metabolism in mouse placentas, and maternal exercise could be an effective method to reduce the occurrence of FGR or alleviate the adverse outcomes associated with FGR.

Genome-wide scans identify biological and metabolic pathways regulating carcass and meat quality traits in beef cattle

Genome association studies (GWAS) provides knowledge about the genetic architecture of beef-related traits that allow linking the target phenotype to genomic information aiding breeding decision. Thus, the present study aims to uncover the genetic mechanism involved in carcass (REA: rib eye area, BF: backfat thickness, and HCW: hot carcass weight) and meat quality traits (SF: shear-force, MARB: marbling score, and IMF: intramuscular fat content) in Nellore cattle. For this, 6910 young bulls with phenotypic information and 23,859 animals genotyped with 435 k markers were used to perform the weighted single-step GBLUP (WssGBLUP) approach, considering two iterations. The top 10 genomic regions explained 8.13, 11.81, and 9.58% of the additive genetic variance, harboring a total of 119, 143, and 95 positional candidate genes for REA, BF, and HCW, respectively. For meat quality traits, the top 10 windows explained a large proportion of the total genetic variance for SF (14.95%), MARB (17.56%), and IMF (21.41%) surrounding 92, 155, and 111 candidate genes, respectively. Relevant candidate genes (CAST, PLAG1, XKR4, PLAGL2, AQP3/AQP7, MYLK2, WWOX, CARTPT, and PLA2G16) are related to physiological aspects affecting growth, carcass, meat quality, feed intake, and reproductive traits by signaling pathways controlling muscle control, key signal metabolic molecules INS / IGF-1 pathway, lipid metabolism, and adipose tissue development. The GWAS results provided insights into the genetic control of the traits studied and the genes found are potential candidates to be used in the improvement of carcass and meat quality traits.

Whitening of brown adipose tissue inhibits osteogenic differentiation via secretion of S100A8/A9

The mechanism by which brown adipose tissue (BAT) regulates bone metabolism is unclear. Here, we reveal that BAT secretes S100A8/A9, a previously unidentified BAT adipokine (batokine), to impair bone formation. Brown adipocytes-specific knockout of Rheb (RhebBAD KO), the upstream activator of mTOR, causes BAT malfunction to inhibit osteogenesis. Rheb depletion induces NF-κB dependent S100A8/A9 secretion from brown adipocytes, but not from macrophages. In wild-type mice, age-related Rheb downregulation in BAT is associated with enhanced S100A8/A9 secretion. Either batokines from RhebBAD KO mice, or recombinant S100A8/A9, inhibits osteoblast differentiation of mesenchymal stem cells in vitro by targeting toll-like receptor 4 on their surfaces. Conversely, S100A8/A9 neutralization not only rescues the osteogenesis repressed in the RhebBAD KO mice, but also alleviates age-related osteoporosis in wild-type mice. Collectively, our data revealed an unexpected BAT-bone crosstalk driven by Rheb-S100A8/A9, uncovering S100A8/A9 as a promising target for the treatment, and potentially, prevention of osteoporosis.

The mechanism of blood coagulation induced by sodium dehydroacetate via the regulation of the mTOR/ERK pathway in rats

Sodium dehydroacetate (DHA-S), a potent antifungal and antibacterial agent, is widely used in food, feed and cosmetics. However, recent studies have shown that DHA-S could pose a risk for human and animal health. We had previously reported that DHA-S could cause coagulation disorders in rats and chicken. In the present study, we further confirmed that DHA-S induced blood coagulation via VKORC1 and VKORC1L1 in rats, and elucidated the role played by mTOR/ERK signaling. The in vivo studies demonstrated that PT, APTT, and DHA-S content and relative protein expressions in tissues rebounded after drug withdrawal. In BRL-3A cells, 1.0 mM DHA-S increased the expression levels of mTOR, p-mTOR and p-ERK and decreased the levels of VKORC1, VKORC1L1 and Vitamin K. Rapamycin significantly decreased the expression levels of p-mTOR and p-ERK, while FR180204 (p-ERK Inhibition) lead to a decrease in p-ERK level. Rapamycin and FR180202 attenuated the inhibitory effect of DHA-S on VKORC1, VKORC1L1 and vitamin K levels. In addition, DHA-S increased the expression levels of mTOR, p-mTOR and p-ERK in male and female rat livers and prolonged PT and APTT. In summary, this study indicated that DHA-S induced blood coagulation via the modulation of the mTOR/ERK pathway in rats.

Methionine Promotes Milk Synthesis through the BRCC36-BRG1-mTOR Signaling Axis in Mammary Epithelial Cells

Methionine (Met) functions as a key stimulator on the mTOR signaling pathway and milk synthesis, but the molecular mechanism remains incompletely understood. We investigated the regulatory roles of BRCC36 in Met-stimulated milk lipid and protein synthesis, cell proliferation, and the mTOR signaling pathway. Knockdown of BRCC36 promoted milk lipid and protein synthesis in HC11 cells as well as cell proliferation by increasing the levels of mTOR gene transcription and protein phosphorylation. Conversely, the gene activation of BRCC36 had opposite effects. Furthermore, BRCC36 gene activation completely blocked Met stimulation on the BRG1 protein level and mTOR mRNA level and protein phosphorylation. BRCC36 bound to BRG1, and BRCC36 and BRG1 bound to the same region on the mTOR promoter. BRCC36 inhibited the BRG1 protein level and the binding of BRG1 to the mTOR promoter. Met decreased the BRCC36 protein level, and this effect was significantly attenuated by MG132 but not affected by cycloheximide or chloroquine. We further showed that Met increased BRCC36 ubiquitination degradation. Our findings reveal that Met promotes milk lipid and protein synthesis in MECs through the BRCC36-BRG1-mTOR signaling axis.

Age-Related Macular Degeneration and Mitochondria-Associated Autoantibodies: A Review of the Specific Pathogenesis and Therapeutic Strategies

Age-related macular degeneration (AMD) is a severe retinal disease that causes irreversible visual loss and blindness in elderly populations worldwide. The pathological mechanism of AMD is complex, involving the interactions of multiple environmental and genetic factors. A poor understanding of the disease leads to limited treatment options and few effective prevention methods. The discovery of autoantibodies in AMD patients provides an opportunity to explore the pathogenesis and treatment direction of the disease. This review focuses on the mitochondria-associated autoantibodies and summarizes the functional roles of mitochondria under physiological conditions and their alterations during the pathological states. Additionally, it discusses the crosstalk between mitochondria and other organelles, as well as the mitochondria-related therapeutic strategies in AMD.

The mTORC2 signaling network: targets and cross-talks

The mechanistic target of rapamycin, mTOR, controls cell metabolism in response to growth signals and stress stimuli. The cellular functions of mTOR are mediated by two distinct protein complexes, mTOR complex 1 (mTORC1) and mTORC2. Rapamycin and its analogs are currently used in the clinic to treat a variety of diseases and have been instrumental in delineating the functions of its direct target, mTORC1. Despite the lack of a specific mTORC2 inhibitor, genetic studies that disrupt mTORC2 expression unravel the functions of this more elusive mTOR complex. Like mTORC1 which responds to growth signals, mTORC2 is also activated by anabolic signals but is additionally triggered by stress. mTORC2 mediates signals from growth factor receptors and G-protein coupled receptors. How stress conditions such as nutrient limitation modulate mTORC2 activation to allow metabolic reprogramming and ensure cell survival remains poorly understood. A variety of downstream effectors of mTORC2 have been identified but the most well-characterized mTORC2 substrates include Akt, PKC, and SGK, which are members of the AGC protein kinase family. Here, we review how mTORC2 is regulated by cellular stimuli including how compartmentalization and modulation of complex components affect mTORC2 signaling. We elaborate on how phosphorylation of its substrates, particularly the AGC kinases, mediates its diverse functions in growth, proliferation, survival, and differentiation. We discuss other signaling and metabolic components that cross-talk with mTORC2 and the cellular output of these signals. Lastly, we consider how to more effectively target the mTORC2 pathway to treat diseases that have deregulated mTOR signaling.

Identification and characterization of TOR in Macrobrachium rosenbergii and its role in muscle protein and lipid production

The recent scarcity of fishmeal and other resources means that studies on the intrinsic mechanisms of nutrients in the growth and development of aquatic animals at the molecular level have received widespread attention. The target of rapamycin (TOR) pathway has been reported to receive signals from nutrients and environmental stresses, and regulates cellular anabolism and catabolism to achieve precise regulation of cell growth and physiological activities. In this study, we cloned and characterized the full-length cDNA sequence of the TOR gene of Macrobrachium rosenbergii (MrTOR). MrTOR was expressed in all tissues, with higher expression in heart and muscle tissues. In situ hybridization also indicated that MrTOR was expressed in muscle, mainly around the nucleus. RNA interference decreased the expression levels of MrTOR and downstream protein synthesis-related genes (S6K, eIF4E, and eIF4B) (P < 0.05) and the expression and enzyme activity of the lipid synthesis-related enzyme, fatty acid synthase (FAS), and increased enzyme activity of the lipolysis-related enzyme, lipase (LPS). In addition, amino acid injection significantly increased the transcript levels of MrTOR and downstream related genes (S6K, eIF4E, eIF4B, and FAS), as well as triglyceride and total cholesterol tissue levels and FAS activity. Starvation significantly increased transcript levels and enzyme activities of adenylate-activated protein kinase and LPS and decreased transcript levels and enzyme activities of FAS, as well as transcript levels of MrTOR and its downstream genes (P < 0.05), whereas amino acid injection alleviated the starvation-induced decreases in transcript levels of these genes. These results suggested that arginine and leucine activated the TOR signaling pathway, promoted protein and lipid syntheses, and alleviated the pathway changes induced by starvation.

RBM45 reprograms lipid metabolism promoting hepatocellular carcinoma via Rictor and ACSL1/ACSL4

Reprogramming of lipid metabolism during hepatocarcinogenesis is not well elucidated. Here, we aimed to explore pivotal RNA-binding motif proteins (RBMs) in lipid metabolism and their therapeutic potential in hepatocellular carcinoma (HCC). Through bioinformatic analysis, we identified RBM45 as a critical gene of interest among differentially expressed RBMs in HCC, with significant prognostic relevance. RBM45 influenced the malignant biological phenotype and lipid metabolism of HCC cells. Mechanically, RBM45 promotes de novo lipogenesis in HCC by directly targeting two key enzymes involved in long-chain fatty acid synthesis, ACSL1 and ACSL4. RBM45 also targets Rictor, which has been demonstrated to modulate lipid metabolism profoundly. RBM45 also aided lipid degradation through activating a key fatty acid β oxidation enzyme, CPT1A. Thus, RBM45 boosted lipid synthesis and decomposition, indicating an enhanced utility of lipid fuels in HCC. Clinically, body mass index was positively correlated with RBM45 in human HCCs. The combination of a PI3K/AKT/mTOR pathway inhibitor in vitro or Sorafenib in orthotopic liver cancer mouse models with shRBM45 has a more significant therapeutic effect on liver cancer than the drug alone. In summary, our findings highlight the versatile roles of RBM45 in lipid metabolism reprogramming and its therapeutic potential in HCC. Lipids induced RBM45 expression. In turn, RBM45 promoted the utility of lipid in HCCs through accelerating both de novo lipogenesis and fatty acid β oxidation, which required the participation of Rictor, a core component of mTORC2 that has been demonstrated to modulate lipid metabolism potently, as well as ACSL1/ACSL4, two key enzymes of long-chain fatty acid synthesis. When the first-line chemotherapy drug sorafenib is combined with a PI3K/AKT/mTOR pathway inhibitor (MK2206 is an AKT inhibitor, rapamycin is a mTOR inhibitor, and inhibiting RBM45 can significantly inhibit Rictor), cell cycle, proliferation, lipid metabolism reprogramming, and hepatocarcinogenesis can be significantly inhibited, while apoptosis can be significantly enhanced.

Endoplasmic Reticulum Stress and Its Impact on Adipogenesis: Molecular Mechanisms Implicated

Endoplasmic reticulum (ER) stress plays a pivotal role in adipogenesis, which encompasses the differentiation of adipocytes and lipid accumulation. Sustained ER stress has the potential to disrupt the signaling of the unfolded protein response (UPR), thereby influencing adipogenesis. This comprehensive review illuminates the molecular mechanisms that underpin the interplay between ER stress and adipogenesis. We delve into the dysregulation of UPR pathways, namely, IRE1-XBP1, PERK and ATF6 in relation to adipocyte differentiation, lipid metabolism, and tissue inflammation. Moreover, we scrutinize how ER stress impacts key adipogenic transcription factors such as proliferator-activated receptor γ (PPARγ) and CCAAT-enhancer-binding proteins (C/EBPs) along with their interaction with other signaling pathways. The cellular ramifications include alterations in lipid metabolism, dysregulation of adipokines, and aged adipose tissue inflammation. We also discuss the potential roles the molecular chaperones cyclophilin A and cyclophilin B play in adipogenesis. By shedding light on the intricate relationship between ER stress and adipogenesis, this review paves the way for devising innovative therapeutic interventions.

Identification of ferroptosis-related proteins in ameloblastoma based on proteomics analysis

PURPOSE

We used proteomic sequencing and experimental verification to identify the potential ferroptosis-related proteins in ameloblastoma.

METHODS

Samples of ameloblastoma (n = 14) and normal gingival tissues (n = 5) were collected for proteomic sequencing to identify differentially expressed proteins (DEPs) in ameloblastoma. Ferroptosis-related genes were downloaded from FerrDb V2, which were then compared with DEPs to obtain ferroptosis-related DEPs (FR-DEPs). A functional enrichment analysis was performed, and a protein-protein interaction network was built. The hub proteins were screened using the Cytoscape software, and potential drugs targeting them were retrieved from the DrugBank database. A hub protein was selected for immunohistochemical validation, and its expression was assessed in ameloblastomas, odontogenic keratocysts, dentigerous cysts, and normal gingival tissues. The primary ameloblastoma cells were cultured to explore the effect of the protein on the migratory properties of the tumour cells.

RESULTS

A total of 58 FR-DEPs were screened, and six hub proteins were identified: mTOR, NFE2L2, PRKCA, STAT3, EGFR, and CDH1. Immunohistochemical analysis showed that mTOR expression was upregulated in ameloblastomas compared with that in odontogenic keratocysts, dentigerous cysts, and normal gingival tissues. p-mTOR was highly expressed in ameloblastomas, with a positivity rate of 83.3%. In addition, rapamycin, an inhibitor of mTOR, can inhibit the migratory capacity of primary cultured ameloblastoma cells.

CONCLUSION

Our results revealed the ferroptosis-related proteins in ameloblastomas and their underlying biological processes. Additionally, mTOR was overexpressed and was found to be associated with the aggressiveness of ameloblastomas, which may be a potential target for future treatments.

Chlorogenic acid enhances PPARγ-mediated lipogenesis through preventing Lipin 1 nuclear translocation in Staphylococcus aureus-exposed bovine mammary epithelial cells

Chlorogenic acid (CGA) as one of the most ubiquitously dietary polyphenolic compounds, has been reported to have various antimicrobial effects and exhibit strong anti-inflammatory ability. Staphylococcus aureus is a gram-positive bacterium that can induce mastitis. However, the mechanism through which S. aureus infection affects lipid synthesis and whether CGA have protective effect on S. aureus reduced lipid synthesis is not fully understood. In this study, the internalization of S. aureus reduced intracellular lipid droplet formation, decreased the levels of intracellular triacylglycerol, total cholesterol and 7 types of fatty acid and downregulated the expression of lipogenic genes FAS, ACC, and DGAT1 in bovine mammary epithelial cells (BMECs). In addition, we found that S. aureus intracellular infection attenuated mTORC1 activation resulting in Lipin 1 nuclear localization. Remarkablely, S. aureus infection-mediated repression of lipid synthesis related to the mTORC1 signaling and Lipin 1 nuclear localization can be alleviated by CGA. Thus, our findings provide a novel mechanism by which lipid synthesis is regulated under S. aureus infection and the protective effects of CGA on lipid synthesis in BMECs.

Pharmacological effects of mTORC1/C2 inhibitor in a preclinical model of NASH progression

Knowledge of the benefits of mTOR inhibition concerning adipogenesis and inflammation has recently encouraged the investigation of a new generation of mTOR inhibitors for non-alcoholic steatohepatitis (NASH). We investigated whether treatment with a specific mTORC1/C2 inhibitor (Ku-0063794; KU) exerted any beneficial impacts on experimentally-induced NASH in vitro and in vivo. The results indicated that KU decreases palmitic acid-induced lipotoxicity in cultivated primary hepatocytes, thus emerging as a successful candidate for testing in an in vivo NASH dietary model, which adopted the intraperitoneal KU dosing route rather than oral application due to its significantly greater bioavailability in mice. The pharmacodynamics experiments commenced with the feeding of male C57BL/6 mice with a high-fat atherogenic western-type diet (WD) for differing intervals over several weeks aimed at inducing various phases of NASH. In addition to the WD, the mice were treated with KU for 3 weeks or 4 months. Acute and chronic KU treatments were observed to be safe at the given concentrations with no toxicity indications in the mice. KU was found to alleviate NASH-related hepatotoxicity, mitochondrial and oxidative stress, and decrease the liver triglyceride content and TNF-α mRNA in at least one set of in vivo experiments. The KU modulated liver expression of selected metabolic and oxidative stress-related genes depended upon the length and severity of the disease. Although KU failed to completely reverse the histological progression of NASH in the mice, we demonstrated the complexity of mTORC1/C2 signaling regulation and suggest a stratified therapeutic management approach throughout the disease course.

Exploring and exploiting the host cell autophagy during Mycobacterium tuberculosis infection

Tuberculosis, caused by Mycobacterium tuberculosis, is a fatal infectious disease that prevails to be the second leading cause of death from a single infectious agent despite the availability of multiple drugs for treatment. The current treatment regimen involves the combination of several drugs for 6 months that remain ineffective in completely eradicating the infection because of several drawbacks, such as the long duration of treatment and the side effects of drugs causing non-adherence of patients to the treatment regimen. Autophagy is an intracellular degradative process that eliminates pathogens at the early stages of infection. Mycobacterium tuberculosis's unique autophagy-blocking capability makes it challenging to eliminate compared to usual pathogens. The present review discusses recent advances in autophagy-inhibiting factors and mechanisms that could be exploited to identify autophagy-inducing chemotherapeutics that could be used as adjunctive therapy with the existing first-line anti-TB agent to shorten the duration of therapy and enhance cure rates from multidrug-resistant tuberculosis (MDR-TB) and extreme drug-resistant tuberculosis (XDR-TB).

Etiology of lipid-laden macrophages in the lung

Uniquely positioned as sentinel cells constantly exposed to the environment, pulmonary macrophages are vital for the maintenance of the lung lining. These cells are responsible for the clearance of xenobiotics, pathogen detection and clearance, and homeostatic functions such as surfactant recycling. Among the spectrum of phenotypes that may be expressed by macrophages in the lung, the pulmonary lipid-laden phenotype is less commonly studied in comparison to its circulatory counterpart, the atherosclerotic lesion-associated foam cell, or the acutely activated inflammatory macrophage. Herein, we propose that lipid-laden macrophage formation in the lung is governed by lipid acquisition, storage, metabolism, and export processes. The cellular balance of these four processes is critical to the maintenance of homeostasis and the prevention of aberrant signaling that may contribute to lung pathologies. This review aims to examine mechanisms and signaling pathways that are involved in lipid-laden macrophage formation and the potential consequences of this phenotype in the lung.

2-Geranyl-1-methoxyerythrabyssin II alleviates lipid accumulation and inflammation in hepatocytes through AMPK activation and AKT inhibition

A growing proportion of the global adult and pediatric populations are currently affected by nonalcoholic steatohepatitis (NASH), leading to rising rates of liver fibrosis and hepatocellular carcinoma without effective pharmacotherapy. Here, we investigated whether 2-geranyl-1-methoxyerythrabyssin II (GMET), isolated from Lespedeza bicolor, could alleviate lipid accumulation and inflammatory responses in a NASH model. GMET exhibited potent in vitro and in vivo effects against lipid accumulation and attenuated inflammatory responses without cytotoxicity. Mechanistically, GMET inhibits acetyl-CoA carboxylase (ACC), sterol regulatory element-binding proteins-1c (SREBP1), and mammalian target of rapamycin (mTOR), and activates PPARα by activating AMP-activated kinase (AMPK), leading to the alleviation of lipid accumulation. In addition, GMET suppresses the NF-κB pathway by activating AMPK and inhibiting the activated protein kinase B (AKT)/IκB-kinase (IKK) pathway, leading to the inhibition of the inflammatory response in hepatocytes. All these protective effects of GMET on lipid accumulation and inflammation in vivo and in vitro were largely abolished by co-treatment with dorsomorphin, an AMPK inhibitor. In conclusion, GMET alleviated lipid accumulation and inflammation to preserve normal hepatocyte function in steatohepatitis. Thus, GMET is a novel potential multi-targeting compound to improve steatohepatitis.

The outcome of boosting mitochondrial activity in alcohol-associated liver disease is organ-dependent

BACKGROUND AND AIMS

Alcohol-associated liver disease (ALD) accounts for 70% of liver-related deaths in Europe, with no effective approved therapies. Although mitochondrial dysfunction is one of the earliest manifestations of alcohol-induced injury, restoring mitochondrial activity remains a problematic strategy due to oxidative stress. Here, we identify methylation-controlled J protein (MCJ) as a mediator for ALD progression and hypothesize that targeting MCJ may help in recovering mitochondrial fitness without collateral oxidative damage.

APPROACH AND RESULTS

C57BL/6 mice [wild-type (Wt)] Mcj knockout and Mcj liver-specific silencing (MCJ-LSS) underwent the NIAAA dietary protocol (Lieber-DeCarli diet containing 5% (vol/vol) ethanol for 10 days, plus a single binge ethanol feeding at day 11). To evaluate the impact of a restored mitochondrial activity in ALD, the liver, gut, and pancreas were characterized, focusing on lipid metabolism, glucose homeostasis, intestinal permeability, and microbiota composition. MCJ, a protein acting as an endogenous negative regulator of mitochondrial respiration, is downregulated in the early stages of ALD and increases with the severity of the disease. Whole-body deficiency of MCJ is detrimental during ALD because it exacerbates the systemic effects of alcohol abuse through altered intestinal permeability, increased endotoxemia, and dysregulation of pancreatic function, which overall worsens liver injury. On the other hand, liver-specific Mcj silencing prevents main ALD hallmarks, that is, mitochondrial dysfunction, steatosis, inflammation, and oxidative stress, as it restores the NAD + /NADH ratio and SIRT1 function, hence preventing de novo lipogenesis and improving lipid oxidation.

CONCLUSIONS

Improving mitochondrial respiration by liver-specific Mcj silencing might become a novel therapeutic approach for treating ALD.

Chromogranin A and its derived peptides: potential regulators of cholesterol homeostasis

Chromogranin A (CHGA), a member of the granin family of proteins, has been an attractive therapeutic target and candidate biomarker for several cardiovascular, neurological, and inflammatory disorders. The prominence of CHGA stems from the pleiotropic roles of several bioactive peptides (e.g., catestatin, pancreastatin, vasostatins) generated by its proteolytic cleavage and by their wide anatomical distribution. These peptides are emerging as novel modulators of cardiometabolic diseases that are often linked to high blood cholesterol levels. However, their impact on cholesterol homeostasis is poorly understood. The dynamic nature of cholesterol and its multitudinous roles in almost every aspect of normal body function makes it an integral component of metabolic physiology. A tightly regulated coordination of cholesterol homeostasis is imperative for proper functioning of cellular and metabolic processes. The deregulation of cholesterol levels can result in several pathophysiological states. Although studies till date suggest regulatory roles for CHGA and its derived peptides on cholesterol levels, the mechanisms by which this is achieved still remain unclear. This review aims to aggregate and consolidate the available evidence linking CHGA with cholesterol homeostasis in health and disease. In addition, we also look at common molecular regulatory factors (viz., transcription factors and microRNAs) which could govern the expression of CHGA and genes involved in cholesterol homeostasis under basal and pathological conditions. In order to gain further insights into the pathways mediating cholesterol regulation by CHGA/its derived peptides, a few prospective signaling pathways are explored, which could act as primers for future studies.

Neglected PTM in Animal Adipogenesis: E3-mediated Ubiquitination

Ubiquitination is a widespread post-transcriptional modification (PTM) that occurs during protein degradation in eukaryotes and participates in almost all physiological and pathological processes, including animal adipogenesis. Ubiquitination is a cascade reaction regulated by the activating enzyme E1, conjugating enzyme E2, and ligase E3. Several recent studies have reported that E3 ligases play important regulatory roles in adipogenesis. However, as a key influencing factor for the recognition and connection between the substrate and ubiquitin during ubiquitination, its regulatory role in adipogenesis has not received adequate attention. In this review, we summarize the E3s' regulation and modification targets in animal adipogenesis, explain the regulatory mechanisms in lipogenic-related pathways, and further analyze the existing positive results to provide research directions of guiding significance for further studies on the regulatory mechanisms of E3s in animal adipogenesis.

Unsupervised Hierarchical Clustering of Head and Neck Cancer Patients by Pre-Treatment Plasma Metabolomics Creates Prognostic Metabolic Subtypes

There is growing evidence that the metabolism is deeply intertwined with head and neck squamous cell carcinoma (HNSCC) progression and survival but little is known about circulating metabolite patterns and their clinical potential. We performed unsupervised hierarchical clustering of 209 HNSCC patients via pre-treatment plasma metabolomics to identify metabolic subtypes. We annotated the subtypes via pathway enrichment analysis and investigated their association with overall and progression-free survival. We stratified the survival analyses by smoking history. High-resolution metabolomics extracted 186 laboratory-confirmed metabolites. The optimal model created two patient clusters, of subtypes A and B, corresponding to 41% and 59% of the study population, respectively. Fatty acid biosynthesis, acetyl-CoA transport, arginine and proline, as well as the galactose metabolism pathways differentiated the subtypes. Relative to subtype B, subtype A patients experienced significantly worse overall and progression-free survival but only among ever-smokers. The estimated three-year overall survival was 61% for subtype A and 86% for subtype B; log-rank p = 0.001. The association with survival was independent of HPV status and other HNSCC risk factors (adjusted hazard ratio = 3.58, 95% CI: 1.46, 8.78). Our findings suggest that a non-invasive metabolomic biomarker would add crucial information to clinical risk stratification and raise translational research questions about testing such a biomarker in clinical trials.

Steroid hormone 20-hydroxyecdysone disturbs fat body lipid metabolism and negatively regulates gluconeogenesis in Hyphantria cunea larvae

The steroid hormone 20-hydroxyecdysone (20E) has been described to regulate fat body lipid metabolism in insects, but its accurate regulatory mechanism, especially the crosstalk between 20E-induced lipid metabolism and gluconeogenesis remains largely unclear. Here, we specially investigated the effect of 20E on lipid metabolism and gluconeogenesis in the fat body of Hyphantria cunea larvae, a notorious pest in forestry. Lipidomics analysis showed that a total of 1 907 lipid species were identified in the fat body of H. cunea larvae assigned to 6 groups and 48 lipid classes. The differentially abundant lipids analysis showed a significant difference between 20E-treated and control samples, indicating that 20E caused a remarkable alteration of lipidomics profiles in the fat body of H. cunea larvae. Further studies demonstrated that 20E accelerated fatty acid β-oxidation, inhibited lipid synthesis, and promoted lipolysis. Meanwhile, the activities of pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase, and glucose-6-phosphatase were dramatically suppressed by 20E in the fat body of H. cunea larvae. As well, the transcriptions of genes encoding these 4 rate-limiting gluconeogenic enzymes were significantly downregulated in the fat body of H. cunea larvae after treatment with 20E. Taken together, our results revealed that 20E disturbed fat body lipid homeostasis, accelerated fatty acid β-oxidation and promoted lipolysis, but negatively regulated gluconeogenesis in H. cunea larvae. The findings might provide a new insight into hormonal regulation of glucose and lipid metabolism in insect fat body.

Physiological and pathological roles of lipogenesis

Lipids are essential metabolites, which function as energy sources, structural components and signalling mediators. Most cells are able to convert carbohydrates into fatty acids, which are often converted into neutral lipids for storage in the form of lipid droplets. Accumulating evidence suggests that lipogenesis plays a crucial role not only in metabolic tissues for systemic energy homoeostasis but also in immune and nervous systems for their proliferation, differentiation and even pathophysiological roles. Thus, excessive or insufficient lipogenesis is closely associated with aberrations in lipid homoeostasis, potentially leading to pathological consequences, such as dyslipidaemia, diabetes, fatty liver, autoimmune diseases, neurodegenerative diseases and cancers. For systemic energy homoeostasis, multiple enzymes involved in lipogenesis are tightly controlled by transcriptional and post-translational modifications. In this Review, we discuss recent findings regarding the regulatory mechanisms, physiological roles and pathological importance of lipogenesis in multiple tissues such as adipose tissue and the liver, as well as the immune and nervous systems. Furthermore, we briefly introduce the therapeutic implications of lipogenesis modulation.

Hepatic follistatin increases basal metabolic rate and attenuates diet-induced obesity during hepatic insulin resistance

OBJECTIVE

Body weight change and obesity follow the variance of excess energy input balanced against tightly controlled EE (energy expenditure). Since insulin resistance can reduce energy storage, we investigated whether genetic disruption of hepatic insulin signaling reduced adipose mass with increased EE.

METHODS

Insulin signaling was disrupted by genetic inactivation of Irs1 (Insulin receptor substrate 1) and Irs2 in hepatocytes of LDKO mice (Irs1L/L·Irs2L/L·CreAlb), creating a state of complete hepatic insulin resistance. We inactivated FoxO1 or the FoxO1-regulated hepatokine Fst (Follistatin) in the liver of LDKO mice by intercrossing LDKO mice with FoxO1L/L or FstL/L mice. We used DEXA (dual-energy X-ray absorptiometry) to assess total lean mass, fat mass and fat percentage, and metabolic cages to measure EE (energy expenditure) and estimate basal metabolic rate (BMR). High-fat diet was used to induce obesity.

RESULTS

Hepatic disruption of Irs1 and Irs2 (LDKO mice) attenuated HFD (high-fat diet)-induced obesity and increased whole-body EE in a FoxO1-dependent manner. Hepatic disruption of the FoxO1-regulated hepatokine Fst normalized EE in LDKO mice and restored adipose mass during HFD consumption; moreover, hepatic Fst disruption alone increased fat mass accumulation, whereas hepatic overexpression of Fst reduced HFD-induced obesity. Excess circulating Fst in overexpressing mice neutralized Mstn (Myostatin), activating mTORC1-promoted pathways of nutrient uptake and EE in skeletal muscle. Similar to Fst overexpression, direct activation of muscle mTORC1 also reduced adipose mass.

CONCLUSIONS

Thus, complete hepatic insulin resistance in LDKO mice fed a HFD revealed Fst-mediated communication between the liver and muscle, which might go unnoticed during ordinary hepatic insulin resistance as a mechanism to increase muscle EE and constrain obesity.

Sertoli cell adaptation to glucose deprivation: Potential role of AMPK in the regulation of lipid metabolism

Sertoli cells (SCs) provide an adequate environment for germ cell development. SCs possess unique features that meet germ cells' metabolic demands: they produce lactate from glucose, which is delivered as energy substrate to germ cells. SCs store fatty acids (FAs) as triacylglycerols (TAGs) in lipid droplets (LDs) and can oxidize FAs to sustain their own energetic demands. They also produce ketone bodies from FAs. It has been shown that exposure of SCs to metabolic stresses, such as glucose deprivation, triggers specific adaptive responses that sustain cell survival and preserve lactate supply to germ cells. The aim of the present study was to investigate whether there are modifications in rat SCs lipid metabolism, including LD content, FA oxidation, and ketone bodies production, as part of their adaptive response to glucose deprivation. The present study was performed in 20-day-old rat SCs cultures. We determined LD content by Oil Red O staining, FA oxidation by measuring the release of ³ H₂ O from [³ H] palmitate, TAGs and 3-hydroxybutyrate levels by spectrophotometric methods, and mRNA levels by RT-qPCR. Results show that the absence of glucose in SC culture medium entails: (1) a decrease in LD content and TAGs levels that is accompanied by decreased perilipin 1 mRNA levels, (2) an increase in FA oxidation that is in part mediated by AMP kinase (AMPK) activation and (3) a decrease in 3-hydroxybutyrate production. Additionally, we studied whether sestrins (SESN1, 2 and 3), proteins involved in the cellular response to stress, are regulated in glucose deprivation conditions. We show that there is an increase in SESN2 mRNA levels in deprived conditions. In conclusion, glucose deprivation affects SC lipid metabolism promoting FA mobilization from LDs to be used as energy source.

Acupuncture inhibits autophagy and repairs synapses by activating the mTOR pathway in Parkinson's disease depression model rats

Acupuncture is a good treatment for depression in Parkinson's disease (DPD), so the possible mechanism of acupuncture in the treatment of DPD was explored in this study. Firstly, observing the behavioral changes of the DPD rat model, the regulation of monoamine neurotransmitters dopamine (DA) and 5-hydroxytryptamine (5-HT) in the midbrain, the change of α-synuclein (α-syn) in the striatum, the efficacy of acupuncture in the treatment of DPD was discussed. Secondly, autophagy inhibitors and activators were selected to judge the effect of acupuncture on autophagy in the DPD rat model. Finally, an mTOR inhibitor was used to observe the effect of acupuncture on the mTOR pathway in the DPD rat model. The results showed that acupuncture could improve the motor and depressive symptoms of DPD model rats, increase the content of DA and 5-HT, and decrease the content of ɑ-syn in the striatum. Acupuncture inhibited the expression of autophagy in the striatum of DPD model rats. At the same time, acupuncture upregulates p-mTOR expression, inhibits autophagy, and promotes synaptic protein expression. Therefore, we concluded that acupuncture might improve the behavior of DPD model rats by activating the mTOR pathway, inhibiting autophagy from removing α-syn and repairing synapses.

Molecular Genetics of Abnormal Redox Homeostasis in Type 2 Diabetes Mellitus

Numerous studies have shown that oxidative stress resulting from an imbalance between the production of free radicals and their neutralization by antioxidant enzymes is one of the major pathological disorders underlying the development and progression of type 2 diabetes (T2D). The present review summarizes the current state of the art advances in understanding the role of abnormal redox homeostasis in the molecular mechanisms of T2D and provides comprehensive information on the characteristics and biological functions of antioxidant and oxidative enzymes, as well as discusses genetic studies conducted so far in order to investigate the contribution of polymorphisms in genes encoding redox state-regulating enzymes to the disease pathogenesis.

The function of long non-coding RNA in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease is a disease that is currently prevalent in the world, increasingly becoming the mainstay of liver diseases. And its prevalence is rapidly increasing, but its pathogenesis is not entirely understood. Long non-coding RNAs have increasingly gained attention as science has progressed in recent years. Studies have shown that long non-coding RNAs are involved in a variety of biological processes in vivo, such as proliferation, differentiation, and apoptosis, and can affect disease by regulating gene expression. This review explores the biological processes involving long non-coding RNAs, including lipid metabolism, glucose metabolism, liver fibrosis, and apoptosis. In addition, we summarize how the different long non-coding RNAs involved in each process function. Finally, the shortcomings of long non-coding RNAs as potential therapeutic targets are briefly described. In conclusion, this article provides a clear visualization of the link that exists between long non-coding RNAs and non-alcoholic fatty liver disease.

Smilax china L. Polyphenols Improves Insulin Resistance and Obesity in High-fat Diet-induced Mice Through IRS/AKT-AMPK and NF-κB Signaling Pathways

Smilax china L. is an important herb used in traditional Chinese medicine. In this study, the mechanism of Smilax china L. polyphenols (SCP) on insulin resistance and anti-obesity in mice induced by a high-fat diet (HFD) was investigated. Fifty female mice were randomly divided into five groups: control, HFD and low, medium, and high doses of SCP for 70 d. SCP significantly decreased intraperitoneal adipose tissue index, body weight gain, liver lipids, and serum inflammatory factor levels. Blood glucose and insulin concentrations, as well as insulin resistance index in SCP, were significantly lower than those in HFD. In addition, SCP markedly up-regulated the gene expression of glucose transporter 4 (GLUT4), insulin receptor substrate 1 (IRS1), insulin receptor substrate 2 (IRS2), serine-threonine kinase (AKT), Acyl-CoA oxidase (ACO), and protein kinase A (PKA), and down-regulated the expression of mammalian target of rapamycin complex 1 (mTORC1), sterol-responsive element-binding protein-1c (SREBP1c), fatty acid synthase (FAS), 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGCR), and forkhead box protein O1 (FOXO1). SCP significantly increased the protein expression of AKT, GLUT4, AMP-activated protein kinase (AMPK), phosphorylated-AMPK (p-AMPK), phosphorylated-AKT (p-AKT), and uncoupling protein 1 (UCP-1), and decreased the expression of SREBP1c, FAS, HMGCR, phosphorylation of IKBα (p-IKBα), and nuclear factor kappa B subunit p65 (P65) in the liver. Overall, SCP effectively reduced HFD-induced insulin resistance and obesity in mice, partly through NF-κB and IRS/AKT-AMPK signaling pathways to regulate inflammatory factors. Therefore, SCP may improve lifestyle diseases.

The Development of Dyslipidemia in Chronic Kidney Disease and Associated Cardiovascular Damage, and the Protective Effects of Curcuminoids

Chronic kidney disease (CKD) is a health problem that is constantly growing. This disease presents a diverse symptomatology that implies complex therapeutic management. One of its characteristic symptoms is dyslipidemia, which becomes a risk factor for developing cardiovascular diseases and increases the mortality of CKD patients. Various drugs, particularly those used for dyslipidemia, consumed in the course of CKD lead to side effects that delay the patient's recovery. Therefore, it is necessary to implement new therapies with natural compounds, such as curcuminoids (derived from the Curcuma longa plant), which can cushion the damage caused by the excessive use of medications. This manuscript aims to review the current evidence on the use of curcuminoids on dyslipidemia in CKD and CKD-induced cardiovascular disease (CVD). We first described oxidative stress, inflammation, fibrosis, and metabolic reprogramming as factors that induce dyslipidemia in CKD and their association with CVD development. We proposed the potential use of curcuminoids in CKD and their utilization in clinics to treat CKD-dyslipidemia.

A DUAL MTOR/NAD+ ACTING GEROTHERAPY

The geroscience hypothesis states that a therapy that prevents the underlying aging process should prevent multiple aging related diseases. The mTOR (mechanistic target of rapamycin)/insulin and NAD+ (nicotinamide adenine dinucleotide) pathways are two of the most validated aging pathways. Yet, it's largely unclear how they might talk to each other in aging. In genome-wide CRISPRa screening with a novel class of N-O-Methyl-propanamide-containing compounds we named BIOIO-1001, we identified lipid metabolism centering on SIRT3 as a point of intersection of the mTOR/insulin and NAD+ pathways. In vivo testing indicated that BIOIO-1001 reduced high fat, high sugar diet-induced metabolic derangements, inflammation, and fibrosis, each being characteristic of non-alcoholic steatohepatitis (NASH). An unbiased screen of patient datasets suggested a potential link between the anti-inflammatory and anti-fibrotic effects of BIOIO-1001 in NASH models to those in amyotrophic lateral sclerosis (ALS). Directed experiments subsequently determined that BIOIO-1001 was protective in both sporadic and familial ALS models. Both NASH and ALS have no treatments and suffer from a lack of convenient biomarkers to monitor therapeutic efficacy. A potential strength in considering BIOIO-1001 as a therapy is that the blood biomarker that it modulates, namely plasma triglycerides, can be conveniently used to screen patients for responders. More conceptually, to our knowledge BIOIO-1001 is a first therapy that fits the geroscience hypothesis by acting on multiple core aging pathways and that can alleviate multiple conditions after they have set in.

Adipose Rheb deficiency promotes miR-182-5p expression via the cAMP/PPARγ signaling pathway

Dysregulation of microRNAs (miRNAs) in adipocytes plays a critical role in the pathogenesis of obesity. However, the signaling mechanisms regulating miRNAs production in adipose tissue remain largely unclear. Here, we show that adipose tissue-specific knockout of Ras homolog enriched in brain (Rheb), a direct upstream activator of mTOR, increases miR-182-5p level in mouse subcutaneous white adipose tissues. Interestingly, the inhibition of mTOR signaling by rapamycin has no effect on miR-182-5p level in primary subcutaneous white adipocytes, suggesting the presence of a mTOR-independent mechanism regulating Rheb-mediated miR-182-5p expression. Consistent with this view, Rheb-ablation activates the cAMP/PPARγ signaling pathway. In addition, treatment of white adipocytes with pioglitazone, a PPARγ agonist, dramatically upregulates miR-182-5p levels. Our study reveals a unique mechanism by which Rheb regulates miR-182-5p in adipocytes. Given that increasing miR-182-5p in adipose tissue promotes beige fat development, our study also suggests a unique mechanism by which Rheb promotes thermogenesis and energy expenditure.

Lead induced disorders of lipid metabolism and glycometabolism in the liver of developmental Japanese quails (Coturnix japonica) via inhibiting PI3K/Akt signaling pathway

The lead (Pb) contamination is considered a lethal threat to birds. However, Pb-induced hepatotoxicology especially its impacts on metabolic processes in the liver of birds is not yet fully understood. Therefore, we tried to determine the toxicological effects of Pb exposure on hepatic carbohydrate and lipid metabolism via Phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway by using an animal model- Japanese quail (Coturnix japonica). One-week old female Japanese quails were randomly allocated into four groups and fed with 0, 50 ppm, 500 ppm and 1000 ppm Pb drinking water respectively for 49 days. The results showed that Pb accumulated in the liver as a dose-dependent manner. Exposure to high dose of Pb (500 and 1000 ppm Pb) led to severe histopathological damages characterized by irregularity and dilation of liver sinusoids, hepatic lipid vacuolization and hepatocellular cytoplasm hyalinization. Meanwhile, Pb exposure caused glycogen increase and lipid droplets decrease in the liver. Pb exposure was also attributable to a decreased triglyceride level in the plasma. In addition, the transcriptional levels of PI3K and Akt in the liver were downregulated by Pb exposure. Subsequently, the mRNA expressions of genes related with glycometabolism in the liver were remarkably altered and the mRNA levels of genes involved in fat synthesis and oxidation in the liver were also markedly changed. it seems that Pb could lead to liver metabolic disorder through structural damages and PI3K/Akt signaling pathway disruption.

Resveratrol Ameliorates Hyperglycemic Cultured Cells and Inhibits the Rheb/mTOR Interaction

Resveratrol (RSV) is a natural polyphenol with anti-diabetic effects and has been reported to ameliorate diabetes-induced metabolic disorders through regulating activities of the mTOR signaling pathway. To delineate the effects of RSV treatment on the mTOR signaling pathway, hyperglycemic HepG2 cells were used for the following experiments. Cellular glucose uptake assays showed that high-glucose levels in the culture medium decelerate the glucose uptake of cultured cells. Co-immunoprecipitation showed that high-glucose culture promotes the interaction between mTOR and Rheb-GTP, which is the active form of Rheb. RSV treatment of the cells suppressed this interaction and accelerated the glucose uptake. Western blotting revealed that RSV down-regulated members of the mTOR signaling pathway, namely SREBP1, p70, and S6. Additionally, RSV ameliorated the metabolic disorders, including the decreased levels of AMPK, glycogen synthase, and glucose-6-phosphatase, in hyperglycemic HepG2 cells. These results indicate that RSV inhibits the Rheb/mTOR interaction and ameliorates metabolic disorders associated with high-glucose levels.

Receptor-Mediated Redox Imbalance: An Emerging Clinical Avenue against Aggressive Cancers

Cancer cells are more vulnerable to abnormal redox fluctuations due to their imbalanced antioxidant system, where cell surface receptors sense stress and trigger intracellular signal relay. As canonical targets of many targeted therapies, cell receptors sensitize the cells to specific drugs. On the other hand, cell target mutations are commonly associated with drug resistance. Thus, exploring effective therapeutics targeting diverse cell receptors may open new clinical avenues against aggressive cancers. This paper uses focused case studies to reveal the intrinsic relationship between the cell receptors of different categories and the primary cancer hallmarks that are associated with the responses to external or internal redox perturbations. Cold atmospheric plasma (CAP) is examined as a promising redox modulation medium and highly selective anti-cancer therapeutic modality featuring dynamically varying receptor targets and minimized drug resistance against aggressive cancers.

mTORC1 regulates a lysosome-dependent adaptive shift in intracellular lipid species

The mechanistic target of rapamycin complex 1 (mTORC1) senses and relays environmental signals from growth factors and nutrients to metabolic networks and adaptive cellular systems to control the synthesis and breakdown of macromolecules; however, beyond inducing de novo lipid synthesis, the role of mTORC1 in controlling cellular lipid content remains poorly understood. Here we show that inhibition of mTORC1 via small molecule inhibitors or nutrient deprivation leads to the accumulation of intracellular triglycerides in both cultured cells and a mouse tumor model. The elevated triglyceride pool following mTORC1 inhibition stems from the lysosome-dependent, but autophagy-independent, hydrolysis of phospholipid fatty acids. The liberated fatty acids are available for either triglyceride synthesis or β-oxidation. Distinct from the established role of mTORC1 activation in promoting de novo lipid synthesis, our data indicate that mTORC1 inhibition triggers membrane phospholipid trafficking to the lysosome for catabolism and an adaptive shift in the use of constituent fatty acids for storage or energy production.

Shuangyu Tiaozhi decoction alleviates non-alcoholic fatty liver disease by improving lipid deposition, insulin resistance, and inflammation in vitro and in vivo

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. Our previous studies have found that Shuangyu Tiaozhi Decoction (SYTZD) could produce an improvement in NAFLD-related indicators, but the underlying mechanism associated with this improvement remains unclear. The study aimed to investigate the potential mechanism of SYTZD against NAFLD through network pharmacology and experimental verification. The components of SYTZD and SYTZD drug containing serum were analyzed using ultra-performance liquid chromatography to quadrupole/time-of-flight mass spectrometry (UPLC-Q/TOF-MS). Active components and targets of SYTZD were screened by the traditional Chinese medical systems pharmacology (TCMSP) and encyclopedia of traditional Chinese medicine (ETCM) databases. NAFLD-related targets were collected from the GeneCards and DisGeNET databases. The component-disease targets were mapped to identify the common targets of SYTZD against NAFLD. Protein-protein interaction (PPI) network of the common targets was constructed for selecting the core targets. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the core targets was performed using the database for annotation, visualization, and integrated discovery (DAVID) database. Furthermore, animal and cell models were constructed for validating the predictions of network pharmacology. Lipid accumulation, liver histopathology, insulin resistance, and core gene expression were measured by oil red O staining, hematoxylin and eosin staining, insulin tolerance test, real-time quantitative polymerase chain reaction, and Western blotting, respectively. Two components and 22 targets of SYTZD against NAFLD were identified by UPLC-Q/TOF-MS and relevant databases. PPI analysis found that ESR1, FASN, mTOR, HIF-1α, VEGFA, and GSK-3β might be the core targets of SYTZD against NAFLD, which were mainly enriched in the thyroid hormone pathway, insulin resistance pathway, HIF-1 pathway, mTOR pathway, and AMPK pathway. Experimental results revealed that SYTZD might exert multiple anti-NAFLD mechanisms, including improvements in lipid deposition, inflammation, and insulin resistance. SYTZD treatment led to decreases in the lipid profiles, hepatic enzyme levels, inflammatory cytokines, and homeostatic model assessment for insulin resistance (HOMA-IR). SYTZD treatment affected relative mRNA and protein levels associated with various pathways. Our findings reveal that SYTZD could alleviate NAFLD through a multi-component, multi-target, and multi-pathway mechanism of action.

Polyphenols: Chemoprevention and therapeutic potentials in hematological malignancies

Polyphenols are one of the largest plant-derived natural product and they play an important role in plants' defense as well as in human health and disease. A number of them are pleiotropic molecules and have been shown to regulate signaling pathways, immune response and cell growth and proliferation which all play a role in cancer development. Hematological malignancies on the other hand, are cancers of the blood. While current therapies are efficacious, they are usually expensive and with unwanted side effects. Thus, the search for newer less toxic agents. Polyphenols have been reported to possess antineoplastic properties which include cell cycle arrest, and apoptosis via multiple mechanisms. They also have immunomodulatory activities where they enhance T cell activation and suppress regulatory T cells. They carry out these actions through such pathways as PI3K/Akt/mTOR and the kynurenine. They can also reverse cancer resistance to chemotherapy agents. In this review, i look at some of the molecular mechanism of action of polyphenols and their potential roles as therapeutic agents in hematological malignancies. Here i discuss their anti-proliferative and anti-neoplastic activities especially their abilities modulate signaling pathways as well as immune response in hematological malignancies. I also looked at clinical studies done mainly in the last 10-15 years on various polyphenol combination and how they enhance synergism. I recommend that further preclinical and clinical studies be carried out to ensure safety and efficacy before polyphenol therapies be officially moved to the clinics.