Triglyceride Storage Research Articles

A MDM2 inhibitor MX69 inhibits adipocytes adipogenesis and differentiation

Adipose tissue, a key regulator of systemic energy homeostasis, can synthesize and store triglycerides to meet long-term energy demands. In response to nutrient overload, adipose tissue expands by hypertrophy or hyperplasia. As an oncogene, MDM2 has exerted diverse biological activities including human development, tissue regeneration, and inflammation, in addition to major oncogenic activities. Recently, some studies indicated that MDM2 plays an important role in adipose tissue function. However, the role of MX69, a MDM2 inhibitor, in adipose tissue function has not been fully elucidated. Here, we administered MX69 intraperitoneally to high-fat diet-induced obesity (DIO) wild type C57BL/6 mice and found that MX69 could promote the body weight and white adipose tissue weight of DIO mice. Moreover, MX69 had no effects on glucose tolerance and insulin sensitivity in DIO mice. And MX69 treatment decreased the size of adipocytes and fat deposition in adipose tissue and inhibited 3T3-L1 preadipocytes differentiation. Mechanistically, MX69 inhibited the protein levels of MDM2 and the mRNA levels of genes related to adipogenesis and differentiation. In summary, our results indicated that MDM2 has a crucial and complex role in regulating adipose tissue function.

Adaptation to short-term extreme fat consumption alters intestinal lipid handling in male and female mice

The small intestine is a highly adaptable organ serving as both a barrier to the external environment and a conduit for nutrient absorption. Enterocytes package dietary triglycerides (TG) into chylomicrons for transport into circulation; the remaining TGs are stored in cytosolic lipid droplets (CLDs). The current study aimed to characterize the impact of diet composition on intestinal lipid handling in male and female wild-type mice. Mice were continued on their grain-based diet (GBD) and switched to either a high-fat, high cholesterol Western-style diet (WD) or a ketogenic diet (KD) for 3 or 5 weeks. KD-fed mice displayed significantly higher plasma TG levels in response to an olive oil gavage than WD- and GBD-fed mice; TG levels were ~2-fold higher in male KD-fed mice than female KD-fed mice. Poloxamer-407 experiments revealed enhanced intestinal-TG secretion rates in male mice fed a KD upon olive oil gavage, whereas secretion rates were unchanged in female mice. Surprisingly, jejunal CLD size and TG mass after oil gavage were similar among the groups. At fasting, TG mass was significantly higher in the jejunum of male KD-fed mice and the duodenum of female KD-fed mice, providing increased substrate for chylomicron formation. In addition to greater fasting intestinal TG stores, KD-fed male mice displayed longer small intestinal lengths, while female mice displayed markedly longer jejunal villi lengths. After 5 weeks of diet, 12 h fasting-2 h refeeding experiments revealed jejunal TG levels were similar between diet groups in male mice; however, in female mice, jejunal TG mass was significantly higher in KD-fed mice compared to GBD- and WD-fed mice. These experiments reveal that KD feeding promotes distinct morphological and functional changes to the murine small intestine compared to the WD diet. Moreover, changes to intestinal lipid handling in response to carbohydrate and protein restriction manifest differently in male and female mice.

Alleviation of Metabolic Disturbance by Substituting Kanjang High in Bacillus for Salt through Modulation of Gut Microbiota in Estrogen-Deficient Rats.

A high salt intake may exacerbate menopausal symptoms and substituting for different types of traditionally made kanjang (TMK; soy sauce) may prevent it. This study examined whether substituting salt with lyophilized TMK containing low and high Bacillus and biogenic amines in a high-fat diet might modulate the menopausal symptoms and the energy, glucose, and lipid metabolism in ovariectomized (OVX) rats. They were categorized into salt (Control), TMK with high Bacillus and low biogenic amines (HBLB), TMK with high Bacillus and high biogenic amines (HBHB), TMK with low Bacillus and low biogenic amines (LBLB), and TMK with low Bacillus and high biogenic amines (LBHB). Sham-operated rats consumed the same diet as the Control. HBLB, HBHB, and LBHB prevented increased tail skin temperature compared to the Control. HBHB and HBLB partially inhibited the increased weight gain and abdominal fat mass by reducing the food efficiency without changing the serum 17β-estradiol concentrations. Serum glucose and insulin concentrations and the insulin resistance index by the homeostatic model assessment for insulin resistance showed a positive association for weight gain. HBLB and HBHB decreased the serum malondialdehyde and tumor-necrosis factor-α levels. Hepatic triglyceride storage was lower in all TMK groups than in the Control, while hepatic glycogen accumulation was higher in the HBLB, HBHB, and LBHB groups than in the Control and LBLB groups. Accordingly, the mRNA expression of peroxisome proliferator-activated receptors-γ(PPAR-γ) was higher in the HBLB and HBHB groups compared to the Control, and that of fatty acid synthase was opposite to PPAR-γ expression. However, HBLB and HBHB improved dyslipidemia and insulin resistance compared to the Control, but their improvement did not reach that of the Normal-control. The acetic acid concentrations in the portal vein were lower in the LBLB than in the Control, while the butyric acid contents were higher in the LBHB and HBLB groups than in the Control. HBHB, HBLB, and LBHB elevated Akkermansia and Lactobacillus, and HBLB and LBLB increased Bacteroides and Ruminococcus compared to the Control. Polycyclic aromatic hydrocarbon degradation, bile acid synthesis, and unsaturated fatty acid biosynthesis were significantly higher in the HBLB group than in the Control group. In conclusion, substituting salts to TMK with a high Bacillus content regardless of the bioamine contents partially improved the menopausal symptoms and metabolic disturbance in estrogen-deficient animals.

The splicing factor 9G8 regulates the expression of NADPH-producing enzyme genes in Drosophila

Excess nutrients are stored as triglycerides, mostly as lipid droplets found in adipose tissue. Previous studies have characterized a group of splicing factors called serine/arginine rich (SR) proteins that function to identify intron/exon borders in regulating metabolic homeostasis in the Drosophila fat body. Decreasing the function of one SR protein, 9G8, causes an increase in triglyceride storage; however, the full complement of genes regulated by 9G8 to control metabolism is unknown. To address this question, we performed RNA sequencing on Drosophila fat bodies with 9G8 levels reduced by RNAi. Differential expression and differential exon usage analyses revealed several genes involved in the immune response, xenobiotic biology, protein translation, sleep, and lipid and carbohydrate metabolism whose expression or splicing is altered in 9G8-RNAi fat bodies. One gene that was both downregulated and had altered splicing in 9G8-RNAi fat bodies was Zwischenferment (Zw), the Drosophila homolog of human glucose 6-phosphate dehydrogenase (G6PD). G6PD regulates flux of glucose 6-phosphate (G6P) into the pentose phosphate pathway, which generates NADPH, a coenzyme for lipid synthesis. Interestingly, the other NADPH-producing enzyme genes in Drosophila (phosphogluconate dehydrogenase, isocitrate dehydrogenase and malic enzyme) were also decreased in 9G8-RNAi flies. Together, these findings suggest that 9G8 regulates several classes of genes and may regulate NADPH-producing enzyme genes to maintain metabolic homeostasis.

Early life stress exacerbates obesity in adult female mice via mineralocorticoid receptor-dependent increases in adipocyte triglyceride and glycerol content

Previously, we have shown that Maternal Separation and Early Weaning (MSEW) exacerbates high fat diet (HF)-induced visceral obesity in female offspring compared to normally reared female mice. Stress hormones such as glucocorticoids and mineralocorticoids are critical mediators in the process of fat expansion, and both can activate the mineralocorticoid receptor (MR) in the adipocyte. Therefore, this study aimed to, comprehend the specific effects of MSEW on adipose tissue basic homeostatic function, and investigate whether female MSEW mice show an exacerbated obesogenic response mediated by MR. Gonadal white adipose tissue (gWAT), a type of visceral fat, was collected to assess lipidomics, transcriptomics, and in vitro lipolysis assay. Obese female MSEW mice showed increased adiposity, elevated 44:2/FA 18:2 + NH4 lipid class and reduced mitochondrial DNA density compared to obese control counterparts. In addition, single-cell RNA sequencing in isolated pre- and mature adipocytes showed a ~9-fold downregulation of aquaglycerolporin 3 (Aqp3), a channel responsible for glycerol efflux in adipocytes. Obese MSEW mice showed high levels of circulating aldosterone and gWAT-derived corticosterone compared to controls. Further, the MR blocker spironolactone (Spiro, 100 mg/kg/day, 2 weeks) normalized the elevated intracellular glycerol levels, the greater in vitro lipolysis response, and the number of large size adipocytes in MSEW mice compared to the controls. Our data suggests that MR plays a role promoting adipocyte hypertrophy in female MSEW mice by preventing lipolysis via glycerol release in favor of triglyceride formation and storage.

Betaine Promotes Fat Accumulation and Reduces Injury in Landes Goose Hepatocytes by Regulating Multiple Lipid Metabolism Pathways.

Simple SummaryBetaine is a safe, effective, naturally occurring trimethylglycine, which is widely used as a nutritional supplement in animal husbandry. Early research showed betaine redistributes body fat by regulating systemic fatty acid metabolism. We previously found that betaine reduces sebum thickness and abdominal fat, and increases liver weight and triglyceride content, in Landes geese fed with high-energy carbohydrates. However, the mechanism underlying these effects remained unclear. Here, we present an in vitro Landes goose fatty liver model, which was developed using primary hepatocytes and a high-glucose medium simulating the conditions of high-energy carbohydrate feeding in vivo. We used this model to investigate the effects of betaine supplementation. Our results suggest that betaine increases lipid deposition, reduces lipid droplet size, and restores mitochondrial membrane potential (β-oxidation) and the expression of genes involved in lipid hydrolysis transfer genes. By contrast, the expression of fatty acid synthesis genes was down-regulated. The comprehensive effect led to an increase in total triglyceride in the liver, but a healthier steatosis phenotype. Overall, these results show that betaine could improve the quality of foie-gras while decreasing the injury to geese that results from overfeeding.Betaine is a well-established supplement used in livestock feeding. In our previous study, betaine was shown to result in the redistribution of body fat, a healthier steatosis phenotype, and an increased liver weight and triglyceride storage of the Landes goose liver, which is used for foie-gras production. However, these effects are not found in other species and strains, and the underlying mechanism is unclear. Here, we studied the underpinning molecular mechanisms by developing an in vitro fatty liver cell model using primary Landes goose hepatocytes and a high-glucose culture medium. Oil red-O staining, a mitochondrial membrane potential assay, and a qRT-PCR were used to quantify lipid droplet characteristics, mitochondrial β-oxidation, and fatty acid metabolism-related gene expression, respectively. Our in vitro model successfully simulated steatosis caused by overfeeding. Betaine supplementation resulted in small, well-distributed lipid droplets, consistent with previous experiments in vivo. In addition, mitochondrial membrane potential was restored, and gene expression of fatty acid synthesis genes (e.g., sterol regulatory-element binding protein, diacylglycerol acyltransferase 1 and 2) was lower after betaine supplementation. By contrast, the expression of lipid hydrolysis transfer genes (mitochondrial transfer protein and lipoprotein lipase) was higher. Overall, the results provide a scientific basis and theoretical support for the use of betaine in animal production.

Evaluation of biological effects of graphene oxide using Drosophila

Graphene and its derivatives have attracted great interest because of their intriguing physical and chemical properties. An increasing phase of commercial production causes the presence of graphene in the environment and might pose a great threat to a wide range of living organisms, including bacteria, viruses, plants, invertebrates and mammals, including humans. In the present study, the graphene oxide (GO) at low doses was evaluated for its biological effects on larvae and the imago of Drosophila melanogaster. Oral administration of GO at concentrations of 0.02-1% has a beneficial effect on the developmental rate and hatching ability of larvae. Long-term administration of a low dose of GO extends Drosophila lifespan and significantly enhances resistance to environmental stresses. We also found that GO exposure led to a remarkable decrease in the level of hemolymph glucose, glycogen and triglycerides storage. These suggest about GO affects carbohydrate and lipid metabolism in adult Drosophila. These findings might provide a useful reference to assess the biological effects of GO, which could play an important role in a variety of graphene-based biomedical applications.

Expression of a constitutively active insulin receptor in Drosulfakinin (Dsk) neurons regulates metabolism and sleep in Drosophila

The ability of organisms to sense their nutritional environment and adjust their behavior accordingly is critical for survival. Insulin-like peptides (ilps) play major roles in controlling behavior and metabolism; however, the tissues and cells that insulin acts on to regulate these processes are not fully understood. In the fruit fly, Drosophila melanogaster, insulin signaling has been shown to function in the fat body to regulate lipid storage, but whether ilps act on the fly brain to regulate nutrient storage is not known. In this study, we manipulate insulin signaling in defined populations of neurons in Drosophila and measure glycogen and triglyceride storage. Expressing a constitutively active form of the insulin receptor (dInR) in the insulin-producing cells had no effect on glycogen or triglyceride levels. However, activating insulin signaling in the Drosulfakinin (Dsk)-producing neurons led to triglyceride accumulation and increased food consumption. The expression of ilp2, ilp3 and ilp5 was increased in flies with activated insulin signaling in the Dsk neurons, which along with the feeding phenotype, may cause the triglyceride storage phenotypes observed in these flies. In addition, expressing a constitutively active dInR in Dsk neurons resulted in decreased sleep in the fed state and less starvation-induced sleep suppression suggesting a role for insulin signaling in regulating nutrient-responsive behaviors. Together, these data support a role for insulin signaling in the Dsk-producing neurons for regulating behavior and maintaining metabolic homeostasis.

Antidiabetic activities of menthone on insulin resistant in 3T3-L1 adipocytes

Background: Diabetes mellitus (DM) is a metabolic disorder characterised by chronic hyperglycaemia and metabolic consequences caused by insulin defects. Adipose tissue is an endocrine organ that influences glucose and lipid metabolism by releasing adipokines; adipose tissue is vital for the life of mammals. It represents the major source of fatty acid. Brown adipose tissue (BAT) and white adipose tissue (WAT) are the basic adipose tissue forms. They have different functions and cellular compositions and localization. They are essentially adversarial in terms of functionality. WAT is known to contain the most body fat; its involvement in the storage of excess dietary triglycerides. It is the source of free fatty aid used as energy substrates for the generation through oxidative phosphate of (ATP) high-energy bonds. During insulin resistance, the secretion of the hormone from the pancreatic islet cells cannot trigger glucose uptake in metabolic tissues, leading to elevated blood glucose and insulin levels. Menthone is cyclic monoterpenes and is reported to have several biological activities. This study, explores the potential antidiabetic effects invitro of menthone in the 3T3L1 adipocytes. Methods: The differentiation of 3T3-L1 preadipocytes into mature adipocytes were cultured and maintained.

MO610: A Graphene-Based Bioactive Compound Reduces Adipogenesis and Increases Lipolysis Via Integrin-Beta1 Interaction: A New Therapeutical Approach Against Obesity

Abstract BACKGROUND AND AIMS Type 2 diabetes and obesity are metabolic disorders related to kidney risk and associated with white adipose tissue (WAT) hypertrophy, which is based in a pro-adipogenic transdifferentiation of the adipocytes and their precursors’ stem cells present in WAT. Several transcription factors are key regulators during this transdifferentiation. The consequence is that adipocytes’ size increases due to the excessive storage of triglycerides (TG) inside the cells. Therapeutic strategies for reducing WAT size may be based in the capacity of increasing lipolysis and reducing adipogenesis. We have previously demonstrated the implication of the extracellular matrix (ECM) mediator integrin beta 1 (INTB1) and intracellular mediation of actin cytoskeleton during obesity (Hatem-Vaquero. J Endocrinol 2017; Cell Physiol Biochem 2020). Here, we demonstrate for the first time the antiobesogenic properties of a new highly biocompatible and bioactive graphene-based product named BioGraph (Llorens-Gámez M. Int J Biol Macromol 2020; Salesa B. Biomedicines 2021), which physicochemical interaction with INTB1 give a great potential as a diagnostic and bioactive therapeutic tool. METHOD Pluripotent c3h10t1/2 cells were differentiated into adipocytes using a specific culture medium. After 7 days of differentiation, the adipocytes were treated for 24 h with a suspension of the graphene derivative BioGraph, developed, registered and patented by Graphenano Medical Care S.L. To determine viability and toxicity on adipocytes, trypan blue and MTT labeling techniques were used. The levels of intracellular TG contained in the lipid droplets were determined by fluorescent labeling with AdipoRed. PPARgamma, CEBP and INTB1 mRNA levels were determined by RT-qPCR. Actin polymerization in the cytoskeleton was quantified by fluorescent phalloidin staining. Active INTB1 quantification (phosphorylated isoform at thr788/9) and total and active lipase HSL (phosphorylated isoform at ser660) were performed by western blot. RESULTS BioGraph is safe and non-toxic on adipocytes in a two-order concentration range. The TG content is reduced in a dose-dependent manner. Adipogenesis markers PPARgamma and CEBP and actin polymerization were reduced after treatment with an intermediate dose. The expression of INTB1 was not modified, but its phosphorylation was increased rapidly after treatment. Lipolysis-main enzyme HSL expression and activity were increased 24 h after treatment. CONCLUSION BioGraph is biocompatible and bioactive on adipocytes. A rapid modulation of INTB1 produces the depolymerization of the cytoskeleton, the reduction of intracellular TG content and the expression of adipogenesis markers, while HSL-mediated lipolysis is increased. We demonstrate for the first time the mechanism followed by a graphene-based material modulating the adipocyte phenotype and behavior. BioGraph may be considered a new anti-obesogenic agent.

Early Life Stress Increases Lipid Storage in Female Mice Fed a High Fat Diet via MR Activation in Adipocytes

We have previously shown that Maternal Separation and Early Weaning (MSEW), a mouse model of early life stress, exacerbates high fat diet (HF)‐induced obesity only in female offspring. Obese female MSEW mice display increased circulating and adrenal‐derived aldosterone and increased gWAT‐derived corticosterone compared with controls (C). Mineralocorticoid receptor (MR) activation has been shown to be critical in the regulation of the differentiation process of pre‐adipocytes into mature adipocytes and overall adipocyte homeostasis. The aim of this study was to determine the role of MR in the mechanism by which MSEW induces perigonadal hypertrophy in female mice fed a high fat diet (HF). MSEW and C mice were weaned onto a HF (60 % Kcal from fat). After 20 weeks, gonadal white adipose tissue (gWAT) was collected to conduct: 1) lipidomic analysis and markers of whitening, 2) collagenase digestion followed by magnetic activated cell sorting for isolation of preadipocytes for RNAseq, and 3) in vitro lipolysis assay. Another subset of mice was randomized to receive vehicle (50% Ora swift in water) or a MR blocker, spironolactone (Spiro, 100 mg/kg/day), for 2 weeks. Female MSEW mice showed increased adiposity along with reduced mitochondrial DNA density (0.81±0.09 and 1.08±0.07 mtDNA/gDNA, p<0.05 MSEW vs. C, respectively). Also, female MSEW mice displayed an increase of over 20 triacyclglycerols TAG, including a 6‐fold increase in 44:2/FA 18:2+NH4 (p<0.05 vs. C). Isolated mature adipocyte RNAseq revealed a 10‐fold downregulation of Aquaglycerolporin 3 (AQP3) in MSEW mice, a channel in adipocytes responsible for glycerol efflux (p<0.05 vs. C). Western blot analysis confirmed this reduction (0.40±0.08 and 1.0±0.14 AQP3/HSP90 p<0.05 MSEW vs. C, respectively). Spiro treatment induced a significant fat mass loss in obese MSEW females (‐3.5±0.9 and ‐1.0±0.5 delta fat mass (%BW) p<0.05 MSEW vs. C, respectively). Increased intracellular glycerol in vehicle‐treated MSEW mice was reduced to levels comparable to controls after Spiro treatment (1.08±0.2 and 1.64±0.12 mg glycerol/mg tissue, p<0.05 MSEW vs. C, respectively) while Spiro also decreased basal and stimulated released glycerol in MSEW mice (p<0.05). There were no differences in plasma glycerol between groups. It has been shown that aldosterone modulates AQP3 expression via MR signaling; however, Spiro treatment did not modify AQP3 protein expression. Overall, this data suggests that MR may play a role in adipose tissue hypertrophy as displayed by MSEW mice by preventing glycerol release in favor of triglyceride formation and storage, suggesting a role for impaired lipolysis that is independent of reduced AQP3 protein expression in adipocyte hypertrophy displayed by obese female MSEW mice.

Microautophagy catabolizes lipid droplets in liver hepatocytes via the small GTPase Rab5 and is connected to alcoholic fatty liver

Introduction and ObjectiveAlcohol consumption has increased dramatically in recent years, representing a significant challenge to human health in metabolic disease. The leading cause of alcohol‐related death is alcohol‐associated liver disease (AALD), which is present at early stages (i.e. steatosis) in 90% of heavy drinkers. During early AALD, liver hepatocytes accumulate large stores of triglycerides in the form of lipid droplets (LDs). Under normal conditions, degradative lysosomes form direct contacts with LDs and catabolize lipid via microlipophagy, a specialized autophagic pathway utilizing the lipid‐degrading enzyme lysosomal acid lipase (LAL). However, the trafficking mechanisms that govern LD‐lysosome contacts during microlipophagy are poorly understood. Several promising candidates exist within the Rab family of small GTPases, which are well‐known to direct the trafficking of intracellular vesicles and LDs. Moreover, previous studies suggest that Rab proteins play central roles in LD catabolism. Thus, the OBJECTIVE of this study was to investigate novel Rab proteins that might be impaired by EtOH leading to altered LD dynamics and microautophagy.Materials and MethodsTo this end, we utilized RNAi gene silencing, subcellular fractionation, Western blot analysis, and high‐resolution microscopy to define Rabs that might target LDs to lysosomes during microlipophagy. To mimic alcoholic fatty liver, cellular and animal models of alcohol consumption were also used. Changes in LD‐lysosome interaction were measured by quantitative confocal microscopy following pharmacological inhibition of LAL by LAListat.ResultsFirst, confocal microscopy revealed that GFP‐Rab5, an early endosomal Rab GTPase, localizes to hepatocellular LDs consistent with proteomic and Western blot analyses showing abundant levels of Rab5 in biochemically isolated LDs. Importantly, siRNA knockdown of Rab5 in cultured hepatocytes showed substantial increases in total LD area (2‐fold) and LD number (1.6‐fold), and also blocked the catabolism of LDs in lipid‐loaded cells. Finally, Rab5 knockdown nearly completely abolished microlipophagy as measured by fluorescent LD accumulation in lysosomes following LAListat treatment. The dissociation of LDs from lysosomes in Rab5 knockdown cells was strikingly similar to the defect observed in EtOH‐fed hepatocytes. Together, these findings suggest that Rab5 is a key mediator of targeting LDs to the lysosome compartment for catabolism and may be a target of EtOH insult.Significance/ImplicationThis study sheds light on new molecular mechanisms of microlipophagy that are affected by chronic alcohol consumption. These mechanisms may represent promising avenues for future therapeutic development toward mitigating hepatic steatosis and slowing the progression of AALD.

Lipotropic activities of aqueous extract of Vernonia guineensis Benth. in Wistar rats fed high fat diet

BackgroundLipotropic molecules are effective therapeutic targets to counteract non-alcoholic fatty liver disease (NAFLD). Lipotropic compounds are capable of removing fat from the liver and/or manage the reduction of the synthesis or deposition of lipids in the liver. The objective of this study was to evaluate the lipotropic effects of the aqueous extract of leaves of Vernonia guineensis (AEVG) on rats fed high fat diet.MethodsTwenty male rats with an average mass of 235 g were allow acclimatize for seven days, following which they were divided into four groups of five animals each. The test group was treated with high fat diet (HFD) and AEVG at 400 mg/kgBW, while positive control group received HFD and Fenofibrate at 100 mg/kgBW. The normal control group received a normal diet; and the negative control group received HFD. After 14 days of treatment, animals were sacrificed, blood and organs (liver, heart and kidneys), as well as the faeces were collected for the preparation of plasma and homogenates respectively. Some markers of lipid profil (total cholesterol, triglycerides, HDL-c, LDL-c,) and markers of toxicity (AST, ALT, γ-GT, creatinine) were evaluated.ResultsThe results obtained showed that a HFD at the hepatic level led to the accumulation of lipids (triglycerides (TG) and total cholesterol (TC)) and had adverse effects on hepatic function by promoting cytolysis. At the plasma level, HFD induced hyperlipidemia. Administration of AEVG at 400 mg/kgBW improved the blood lipid profile and reduced the storage of TG and cholesterol in the liver. AEVG also promoted fecal cholesterol excretion and reduced atherogenic indices which include Total Cholesterol/High-Density Lipoprotein cholesterol (TC/HDL-c) and Low-Density Lipoprotein cholesterol/High-Density Lipoprotein cholesterol (LDL-c/HDL-c). The extract exhibited hepato-protective activity (anticholestasis) and improved glomerular filtration.ConclusionThese findings suggest that AEVG possesses lipotropic effects confirming its probable use in the management of non-alcoholic fatty liver disease and its cardiometabolic complications. This virtue could be exploited for local pharmaceutical development.

Endocrine disruptor chemicals, adipokines and reproductive functions.

The prevalence of adult obesity has risen markedly in recent decades. The endocrine system precisely regulates energy balance, fat abundance and fat deposition. Interestingly, white adipose tissue is an endocrine gland producing adipokines, which regulate whole-body physiology, including energy balance and reproduction. Endocrine disruptor chemicals (EDCs) include natural substances or chemicals that affect the endocrine system by multiple mechanisms and increase the risk of adverse health outcomes. Numerous studies have associated exposure to EDCs with obesity, classifying them as obesogens by their ability to activate different mechanisms, including the differentiation of adipocytes, increasing the storage of triglycerides, or elevating the number of adipocytes. Moreover, in recent years, not only industrial deception and obesity have intensified but also the problem of human infertility. Reproductive functions depend on hormone interactions, the balance of which may be disrupted by various EDCs or obesity. This review gives a brief summary of common EDCs linked with obesity, the mechanisms of their action, and the effect on adipokine levels, reproduction and connected disorders, such as polycystic ovarian syndrome, decrease in sperm motility, preeclampsia, intrauterine growth restriction in females and decrease of sperm motility in males.

Cholecystokinin promotes functional expression of the aquaglycerol channel aquaporin 7 in adipocytes.

Cholecystokinin (CCK) promotes triglyceride storage and adiponectin production in white adipose tissue (WAT), suggesting that CCK modulates WAT homeostasis. Our goal was to investigate the role of CCK in regulating the expression and function of the aquaglycerol channel aquaporin 7 (AQP7), a protein that is pivotal for maintaining adipocyte homeostasis and preserving insulin responsiveness. The effect of the bioactive fragment of CCK, CCK-8, in regulating adipose AQP7 expression and glycerol efflux was assessed in rats as well as in preadipocytes. Moreover, the involvement of insulin receptors in the effects of CCK-8 was characterized in preadipocytes lacking insulin receptors. CCK-8 induced AQP7 gene expression in rat WAT, concomitantly increasing plasma glycerol concentration. In isolated preadipocytes, CCK-8 also enhanced both AQP7 expression and glycerol leakage. The effects of CCK-8 were independent of the lipolysis rate, as CCK-8 failed to promote fatty acid release by adipocytes. In addition, CCK-8 did not enhance hormone sensitive lipase phosphorylation, which is the rate-limiting step of lipolysis. Moreover, the effects of CCK-8 were dependent on the activation of protein kinase B and PPARγ. Silencing insulin receptor expression inhibited CCK-8-induced Aqp7 expression in preadipocytes. Furthermore, insulin enhanced the effect of CCK-8. CCK regulates AQP7 expression and function, and this effect is dependent on insulin. Accordingly, CCK receptor agonists could be suitable for preserving and improving insulin responsiveness in WAT.

Ablation of uncoupling protein 3 affects interrelated factors leading to lipolysis and insulin resistance in visceral white adipose tissue.

The physiological role played by uncoupling protein 3 (UCP3) in white adipose tissue (WAT) has not been elucidated so far. In the present study, we evaluated the impact of the absence of the whole body UCP3 on WAT physiology in terms of ability to store triglycerides, oxidative capacity, response to insulin, inflammation, and adipokine production. Wild type (WT) and UCP3Knockout (KO) mice housed at thermoneutrality (30°C) have been used as the animal model. Visceral gonadic WAT (gWAT) from KO mice showed an impaired capacity to store triglycerides (TG) as indicated by its lowered weight, reduced adipocyte diameter, and higher glycerol release (index of lipolysis). The absence of UCP3 reduces the maximal oxidative capacity of gWAT, increases mitochondrial free radicals, and activates ER stress. These processes are associated with increased levels of monocyte chemoattractant protein-1 and TNF-α. The response of gWAT to in vivo insulin administration, revealed by (ser473)-AKT phosphorylation, was blunted in KO mice, with a putative role played by eif2a, JNK, and inflammation. Variations in adipokine levels in the absence of UCP3 were observed, including reduced adiponectin levels both in gWAT and serum. As a whole, these data indicate an important role of UCP3 in regulating the metabolic functionality of gWAT, with its absence leading to metabolic derangement. The obtained results help to clarify some aspects of the association between metabolic disorders and low UCP3levels.

Enhanced lipogenesis through Pparγ helps cavefish adapt to food scarcity

Nutrient availability varies seasonally and spatially in the wild. While many animals, such as hibernating animals or migrating birds, evolved strategies to overcome periods of nutrient scarcity,1,2 the cellular mechanisms of these strategies are poorly understood. Cave environments represent an example of nutrient-deprived environments, since the lack of sunlight and therefore primary energy production drastically diminishes the nutrient availability.3 Here, we used Astyanax mexicanus, which includes river-dwelling surface fish and cave-adapted cavefish populations, to study the genetic adaptation to nutrient limitations.4-9 We show that cavefish populations store large amounts of fat in different body regions when fed ad libitum in the lab. We found higher expression of lipogenesis genes in cavefish livers when fed the same amount of food as surface fish, suggesting an improved ability of cavefish to use lipogenesis to convert available energy into triglycerides for storage into adipose tissue.10-12 Moreover, the lipid metabolism regulator, peroxisome proliferator-activated receptor γ (Pparγ), is upregulated at both transcript and protein levels in cavefish livers. Chromatin immunoprecipitation sequencing (ChIP-seq) showed that Pparγ binds cavefish promoter regions of genes to a higher extent than surface fish and inhibiting Pparγ invivo decreases fat accumulation in A.mexicanus. Finally, we identified nonsense mutations in per2, a known repressor of Pparγ, providing a possible regulatory mechanism of Pparγ in cavefish. Taken together, our study reveals that upregulated Pparγ promotes higher levels of lipogenesis in the liver and contributes to higher body fat accumulation in cavefish populations, an important adaptation to nutrient-limited environments.

Leptin in Osteoarthritis and Rheumatoid Arthritis: Player or Bystander?

White adipose tissue (WAT) is a specialized tissue whose main function is lipid synthesis and triglyceride storage. It is now considered as an active organ secreting a plethora of hormones and cytokines namely adipokines. Discovered in 1994, leptin has emerged as a key molecule with pleiotropic functions. It is primarily recognized for its role in regulating energy homeostasis and food intake. Currently, further evidence suggests its potent role in reproduction, glucose metabolism, hematopoiesis, and interaction with the immune system. It is implicated in both innate and adaptive immunity, and it is reported to contribute, with other adipokines, in the cross-talking networks involved in the pathogenesis of chronic inflammation and immune-related diseases of the musculo-skeletal system such as osteoarthritis (OA) and rheumatoid arthritis (RA). In this review, we summarize the most recent findings concerning the involvement of leptin in immunity and inflammatory responses in OA and RA.

PLIN1 Haploinsufficiency Causes a Favorable Metabolic Profile.

Context PLIN1 encodes perilipin-1, which coats lipid droplets in adipocytes and is involved in droplet formation, triglyceride storage, and lipolysis. Rare PLIN1 frameshift variants that extend the translated protein have been described to cause lipodystrophy.ObjectiveThis work aimed to test whether PLIN1 protein-truncating variants (PTVs) cause lipodystrophy in a large population-based cohort.MethodsWe identified individuals with PLIN1 PTVs in individuals with exome data in the UK Biobank. We performed gene-burden testing for individuals with PLIN1 PTVs. We replicated the associations using data from the T2D Knowledge portal. We performed a phenome-wide association study using publicly available association statistics. A total of 362 791 individuals in the UK Biobank, a population-based cohort, and 43 125 individuals in the T2D Knowledge portal, a type 2 diabetes (T2D) case-control study, were included in the analyses. Main outcome measures included 22 diseases and traits relevant to lipodystrophy.ResultsThe 735 individuals with PLIN1 PTVs had a favorable metabolic profile. These individuals had increased high-density lipoprotein cholesterol (0.12 mmol/L; 95% CI, 0.09 to 0.14, P = 2 × 10–18), reduced triglycerides (–0.22 mmol/L; 95% CI, –0.29 to –0.14, P = 3 × 10–11), reduced waist-to-hip ratio (–0.02; 95% CI, –0.02 to –0.01, P = 9 × 10–12), and reduced systolic blood pressure (–1.67 mm Hg; 95% CI, –3.25 to –0.09, P = .05). These associations were consistent in the smaller T2D Knowledge portal cohort. In the UK Biobank, PLIN1 PTVs were associated with reduced risk of myocardial infarction (odds ratio [OR] = 0.59; 95% CI, 0.35 to 0.93, P = .02) and hypertension (OR = 0.85; 95% CI, 0.73 to 0.98, P = .03), but not T2D (OR = 0.99; 95% CI, 0.63-1.51, P = .99).ConclusionOur study suggests that PLIN1 haploinsufficiency causes a favorable metabolic profile and may protect against cardiovascular disease.

ChREBP-driven DNL and PNPLA3 Expression Induced by Liquid Fructose are Essential in the Production of Fatty Liver and Hypertriglyceridemia in a High-Fat Diet-Fed Rat Model.

ScopeThe aim of this study is to delineate the contribution of dietary saturated fatty acids (FA) versus liquid fructose to fatty liver and hypertriglyceridemia.Methods and ResultsThree groups of female rats are maintained for 3 months in standard chow (CT); High‐fat diet (46.9% of fat‐derived calories, rich in palmitic and stearic FA, HFD); and HFD with 10% w/v fructose in drinking water (HFHFr). Zoometric parameters, plasma biochemistry, and liver Oil‐Red O (ORO) staining, lipidomics, and expression of proteins involved in FA metabolism are analyzed. Both diets increase ingested calories without modifying body weight. Only the HFHFr diet increases liver triglycerides (x11.0), with hypertriglyceridemia (x1.7) and reduces FA β‐oxidation (x0.7), and increases liver FA markers of DNL (de novo lipogenesis). Whereas HFD livers show a high content of ceramides, HFHFr samples show unchanged ceramides, and an increase in diacylglycerols. Only the HFHFr diet leads to a marked increase in the expression of enzymes involved in DNL and triglyceride metabolism, such as carbohydrate response element binding protein β (ChREBPβ, x3.2), a transcription factor that regulates DNL, and patatin‐like phospholipase domain‐containing 3 (PNPLA3, x2.6), a lipase that mobilizes stored triglycerides for VLDL secretion.ConclusionThe addition of liquid‐fructose to dietary FA is determinant in liver steatosis and hypertriglyceridemia production, through increased DNL and PNPLA3 expression, and reduced FA catabolism.