Zinc alpha2 glycoprotein alleviates palmitic acid-induced intracellular lipid accumulation in hepatocytes

Adipocyte ZAG improves obesity-triggered insulin resistance by reshaping macrophages populations in adipose tissue

Adipose tissues macrophages (ATMs) serve as a critical effector in the mediating occurrence of metabolic inflammation to impact whole-body insulin sensitivity in obesity. Discovering the key adipokines mediating crosstalk of adipocytes-macrophages and understanding the molecular mechanism of ATMs polarization and function have become hot topic issues in the immunometabolism fields. Zinc-α2-glycoprotein (ZAG) as a anti-inflammatory adipokines plays important roles in obesity-related metabolic diseases. We attempt to explore the precise role of adipose ZAG in metabolic inflammation and obesity-associated insulin resistance. Here we showed that Omental ZAG was positively associated with insulin sensitivity and M2 macrophages markers. ZAG-specific ablation in adipocyte aggravated insulin resistance and adipose tissues inflammation as evidenced by enhanced M1 macrophages proportion and inhibited AKT signaling pathway in mice fed with a high-fat diet. Exogenous ZAG inhibits PA-induced M1 macrophage polarization via β3-AR/PKA/STAT3 signaling in RAW264.7 macrophages.These findings suggest that adipocyte ZAG maintain insulin sensitivity via the cross talk with adipose-resident macrophages.

Unlocking the therapeutic potential of canagliflozin in NAFLD: Insights into AMPK/SIRT1-mediated lipophagy

Nonalcoholic fatty liver disease (NAFLD) is a rising global health problem. The antidiabetic canagliflozin (CANA) has been proposed to ameliorate the metabolic abnormalities in NAFLD.

AIM

This study aimed to explore the possible anti-NAFLD effects of CANA in rats and HepG2 cells, focusing on AMPK/SIRT1-mediated lipophagy.

METHODS

Wistar rats were assigned to four groups: control group, NAFLD group, NAFLD+CANA group, and NAFLD+CANA+chloroquine (CQ) group, where CQ served as autophagy inhibitor. HepG2 cells were also divided into four groups: control group, NAFLD group, NAFLD+CANA group, and NAFLD+CANA+compound C (Comp C) group, where Comp C served as AMPK inhibitor.

RESULTS

The histopathological examination showed that CANA alleviated hepatic and intracellular lipid deposition in rats and HepG2 cells. CANA induced lipophagy by increasing LC3-II levels and lowering both p62 and perilipin 2 levels in rats and HepG2 cells, in addition to decreasing mTOR protein expression in rats' livers. These outcomes were associated with upregulation of the lipophagy regulator Rab7 and downregulation of the ER stress-related protein CHOP. CANA enhanced autophagic engulfment of lipid droplets while decreased ER stress and mitochondrial damage in rats' livers, as demonstrated by TEM. In rats, CANA improved hyperglycemia, hyperinsulinemia, dyslipidemia, and obesity. In HepG2 cells, CANA's effects were linked to increased phosphorylated AMPK level and enhanced SIRT1 level and expression. However, blocking lipophagy in rats and AMPK in HepG2 cells markedly weakened CANA's protective effects against NAFLD.

CONCLUSION

CANA ameliorated NAFLD via enhancing AMPK/SIRT1-mediated lipophagy, suggesting its potential as a therapeutic intervention for this metabolic disorder.

Serum Zinc-Alpha-2 Glycoprotein and Zinc Levels and Their Relationship with Insulin Resistance and Biochemical Parameters in Overweight and Obese Children

The biological role of zinc-alpha 2-glycoprotein (ZAG) has been associated with lipid mobilization, although this is not entirely clear. The study's aim was to examine the serum levels of ZAG and zinc (Zn) and the Zn/ZAG in a population of children with overweight (OW) and obesity (OB), and their relationship with biochemical parameters. Our study was a cross-sectional analysis of a group of Mexican children aged 6-10 (n = 72). We analyzed anthropometric data and biochemical parameters, including fasting plasma glucose (FPG), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), triglycerides (TG), total cholesterol (TC), insulin, and homeostatic model assessment insulin resistance (HOMA-IR). ZAG protein levels were measured using enzyme-linked immunosorbent assay (ELISA), and serum zinc (Zn) levels were quantified using inductively coupled plasma mass spectrometry (ICP-MS). The Zn values indicate a statistically significant difference between normal weight (NW) and OW/OB children with Zn concentrations were 91 µg/dL for NW and 66 µg/dL for OW/OB children. ZAG values did not show significant differences between NW and OW/OB, and values were 2.1 mg/dL and 2.3 mg/dL, respectively. The Zn/ZAG ratio was lower in the OW/OB compared to the NW (p = 0.05). Correlations were found between FPG and Zn (p = 0.004) in NW boys, and ZAG (p = 0.046) in OW/OB boys, as well as a negative correlation between insulin and Zn in NW children of both sexes. HOMA-IR shows correlations between Zn (p = 0.008) in OW/OB boys, and ZAG (p = 0.010) in the OW/OB girls. Additionally, correlations were observed between LDLc, TG, and BMIz with Zn and ZAG in the boys. In the same way, we also found that girls with OW/OB had a Zn/ZAG ratio of - 2.32 (p = 0.043) compared to NW boys. In conclusion, our findings highlight the significant roles of Zn and ZAG in glucose and lipid metabolism. Furthermore, Zn/ZAG ratio may provide insights into nutritional deficiencies, adiposity, and metabolic health. However, further studies are necessary to validate our results.

Zinc-alpha2-glycoprotein modulates blood pressure by regulating renal lipid metabolism reprogramming-mediated urinary Na+ excretion in hypertension

AIMS

Organs modulating blood pressure are associated with a common cytokine known as adipokines. We chose Zinc-alpha2-glycoprotein (ZAG) due to its prioritized transcriptional level in the database. Previous studies showed that ZAG is involved in metabolic disorders. The aim of this study was to investigate its role in hypertension.

METHODS AND RESULTS

Serum ZAG levels were assessed in hypertensive and healthy participants. Blood pressure was monitored in Azgp1-/- mice and other animal models by 24-hour ambulatory implanted telemetric transmitters and tail-cuff method. Multi-omics analysis of proteomics and metabolomics were performed to explore possible mechanisms. Serum ZAG levels were significantly decreased and associated with morning urine Na+ excretion in hypertensive participants in a cross-sectional study. This study firstly reported that Azgp1-/- mice exhibited increased blood pressure and impaired urinary Na+ excretion, which were restored by AAV9-mediated renal tubule Azgp1 rescue. Azgp1 knockout caused the reprogramming of renal lipid metabolism, and increased Na+/H+-exchanger (NHE) activity in the renal cortex. Administration with a NHE inhibitor EIPA reversed the impaired urinary Na+ excretion in Azgp1-/- mice. Moreover, the activity of carnitine palmitoyltransferase 1 (CPT1), a key enzyme of fatty acid β-oxidation, was decreased, and the levels of malonyl-CoA, an inhibitor of CPT1, were increased in renal cortex of Azgp1-/- mice. Renal Cpt1 rescue improved urinary Na+ excretion and blood pressure in Azgp1-/- mice, accompanied by decreased renal fatty acid levels and NHE activity. Finally, administration of recombinant ZAG protein improved blood pressure and urinary Na+ excretion in spontaneous hypertension rats.

CONCLUSION

Deficiency of Azgp1 increased the malonyl CoA-mediated inhibition of CPT1 activity, leading to renal lipid metabolism reprogramming, resulting in accumulated fatty acids and increased NHE activity, subsequently decreasing urinary Na+ excretion and causing hypertension. These findings may provide a potential kidney-targeted therapy in the prevention and treatment of hypertension.

Circulating zinc levels and cardiometabolic risk-related variables in adults

Introduction. Altered serum zinc levels, lower and higher than values in healthy controls, have been observed in individuals affected by non-communicable chronic diseases. However, to date, studies describing potential determinants of zinc levels in general populations free of chronic diseases appear to be limited. Objective. To evaluate whether nutrient intake, biochemical and clinical measures, lifestyle, and family history of cardio-metabolic diseases are independently associated with zinc levels in apparently healthy individuals. Materials and methods. We evaluated 239 healthy subjects. Serum zinc was measured via flame atomic absorption spectrometry, and the remaining biochemical markers were assessed using enzymatic colorimetric methods. Standard techniques were employed to quantify waist circumference, height, and weight. Body fat was measured via bioimpedance, and blood pressure was measured using digital sphygmomanometers. We applied a survey to record the personal and family history of non-communicable chronic diseases, and nutrient intake was estimated using the 24-hour recall method. Results. Women had lower serum zinc levels than men. In multivariate analyzes, total fat intake (β = -0.15; standard error = 0.03; p < 0.001), plasma log-triglycerides (β = -10.18; standard error = 3.9; p = 0.010), and female gender (β = -6.81; standard error = 3.3; p = 0.043) were significant predictors for serum zinc levels. Zinc intake was not significantly related to serum zinc in univariate and multivariate analyses. Conclusions. Variables related to cardiometabolic risk, such as plasma triglyceride levels and total fat intake, were associated with serum zinc levels in individuals without a diagnosis of chronic or infectious/inflammatory diseases. Further studies are required to confirm our findings and to evaluate possible biological mechanisms for these relationships.

AZGP1 in POMC neurons modulates energy homeostasis and metabolism through leptin-mediated STAT3 phosphorylation

Zinc-alpha2-glycoprotein (AZGP1) has been implicated in peripheral metabolism; however, its role in regulating energy metabolism in the brain, particularly in POMC neurons, remains unknown. Here, we show that AZGP1 in POMC neurons plays a crucial role in controlling whole-body metabolism. POMC neuron-specific overexpression of Azgp1 under high-fat diet conditions reduces energy intake, raises energy expenditure, elevates peripheral tissue leptin and insulin sensitivity, alleviates liver steatosis, and promotes adipose tissue browning. Conversely, mice with inducible deletion of Azgp1 in POMC neurons exhibit the opposite metabolic phenotypes, showing increased susceptibility to diet-induced obesity. Notably, an increase in AZGP1 signaling in the hypothalamus elevates STAT3 phosphorylation and increases POMC neuron excitability. Mechanistically, AZGP1 enhances leptin-JAK2-STAT3 signaling by interacting with acylglycerol kinase (AGK) to block its ubiquitination degradation. Collectively, these results suggest that AZGP1 plays a crucial role in regulating energy homeostasis and glucose/lipid metabolism by acting on hypothalamic POMC neurons.

The role of novel adipokines and adipose-derived extracellular vesicles (ADEVs): Connections and interactions in liver diseases

Adipose tissues (AT) are an important endocrine organ that secretes various functional adipokines, peptides, non-coding RNAs, and acts on AT themselves or other distant tissues or organs through autocrine, paracrine, or endocrine manners. An accumulating body of evidence has suggested that many adipokines play an important role in liver metabolism. Besides the traditional adipokines such as adiponectin and leptin, many novel adipokines have recently been identified to have regulatory effects on the liver. Additionally, AT can produce extracellular vesicles (EVs) that act on peripheral tissues. However, under pathological conditions, such as obesity and diabetes, dysregulation of adipokines is associated with functional changes in AT, which may cause liver diseases. In this review, we focus on the newly discovered adipokines and EVs secreted by AT and highlight their actions on the liver under the context of obesity, nonalcoholic fatty liver diseases (NAFLD), and some other liver diseases. Clarifying the action of adipokines and adipose tissue-derived EVs on the liver would help to identify novel therapeutic targets or biomarkers for metabolic diseases.

Exploring the interactions between metabolic dysfunction-associated fatty liver disease and micronutrients: from molecular mechanisms to clinical applications

Metabolic (dysfunction)-associated fatty liver disease (MAFLD) has emerged as a significant global health concern, representing a major cause of liver disease worldwide. This condition spans a spectrum of histopathologic stages, beginning with simple fatty liver (MAFL), characterized by over 5% fat accumulation, and advancing to metabolic (dysfunction)-associated steatohepatitis, potentially leading to hepatocellular carcinoma. Despite extensive research, there remains a substantial gap in effective therapeutic interventions. This condition's progression is closely tied to micronutrient levels, crucial for biological functions like antioxidant activities and immune efficiency. The levels of these micronutrients exhibit considerable variability among individuals with MAFLD. Moreover, the extent of deficiency in these nutrients can vary significantly throughout the different stages of MAFLD, with disease progression potentially exacerbating these deficiencies. This review focuses on the role of micronutrients, particularly vitamins A, D, E, and minerals like iron, copper, selenium, and zinc, in MAFLD's pathophysiology. It highlights how alterations in the homeostasis of these micronutrients are intricately linked to the pathophysiological processes of MAFLD. Concurrently, this review endeavors to harness the existing evidence to propose novel therapeutic strategies targeting these vitamins and minerals in MAFLD management and offers new insights into disease mechanisms and treatment opportunities in MAFLD.

New insight of obesity-associated NAFLD: Dysregulated "crosstalk" between multi-organ and the liver?

Obesity plays a crucial role in the development of non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanism for the pathogenesis of obesity-associated NAFLD remains largely obscure. Although the "multiple hit" theory provides a more accurate explanation of NAFLD pathogenesis, it still cannot fully explain precisely how obesity causes NAFLD. The liver is the key integrator of the body's energy needs, receiving input from multiple metabolically active organs. Thus, recent studies have advocated the "multiple crosstalk" hypothesis, highlighting that obesity-related hepatic steatosis may be the result of dysregulated "crosstalk" among multiple extra-hepatic organs and the liver in obesity. A wide variety of circulating endocrine hormones work together to orchestrate this "crosstalk". Of note, with deepening understanding of the endocrine system, the perception of hormones has gradually risen from the narrow sense (i.e. traditional hormones) to the broad sense of hormones as organokines and exosomes. In this review, we focus on the perspective of organic endocrine hormones (organokines) and molecular endocrine hormones (exosomes), summarizing systematically how the two types of new hormones mediate the dialogue between extra-hepatic organs and liver in the pathogenesis of obesity-related NAFLD.

Associations of zinc-α-2-glycoprotein with metabolic syndrome and its components among adult Arabs

Epidemiological studies suggest that the Zinc-α-2-glycoprotein (ZAG) plays significant physiological roles. In this study we investigate whether ZAG could be considered as a clinical biomarker in the diagnosis and prognosis of metabolic syndrome (MetS) in Saudi population. As such insights urgently required for management of MetS. Thus, we have determined serum levels of ZAG in patients with MetS and normal individuals. We have also assessed the correlation between ZAG and different components of MetS. In this case–control study, clinical information of 200 Saudi male and female subjects (age range 30–65) with MetS (n = 100) and healthy controls (n = 100) were extracted from the database of the Chair of Biomarkers of Chronic Disease (CBCD) in King Saud University (KSU), Riyadh, Saudi Arabia. MetS was screened according to NCEP ATP III criteria (National Cholesterol Education Program Adult Treatment Panel III). Fasting glucose and lipid profile levels were measured using Konelab. Serum TNF-α, IL- 6, CRP and ZAG levels were measured using commercially available assays. There was an age-dependent significant increase in ZAG level among MetS subjects than controls (43.8 ± 19.5 vs 48.1 ± 14.8; P = 0.04). A significant inverse correlation between ZAG and serum HDL-cholesterol (r = − 0.20, P < 0.05) was observed. Whereas, triglycerides (r = 0.25, P < 0.01), waist circumference (WHR) (r = 0.17, P < 0.05) and CRP (r = 0.24, P < 0.01) were all significantly and positively associated with ZAG. Circulating ZAG is associated with MetS in an age-dependent manner. Serum ZAG is a potential biomarker for MetS.

The Therapeutic Potential of Zinc-Alpha2-Glycoprotein (AZGP1) in Fibrotic Kidney Disease

Chronic kidney disease (CKD) is characterized by a long-term loss of kidney function and, in most cases, by progressive fibrosis. Zinc-alpha2-glycoprotein (AZGP1) is a secreted protein, which is expressed in many different tissues and has been associated with a variety of functions. In a previous study, we have shown in cell culture and in AZGP1 deficient mice that AZGP1 has protective anti-fibrotic effects. In the present study, we tested the therapeutic potential of an experimental increase in AZGP1 using two different strategies. (1) C57Bl/6J mice were treated systemically with recombinant AZGP1, and (2) a transgenic mouse strain was generated to overexpress AZGP1 conditionally in proximal tubular cells. Mice underwent unilateral uretic obstruction as a pro-fibrotic kidney stress model, and kidneys were examined after 14 days. Recombinant AZGP1 treatment was accompanied by better preservation of tubular integrity, reduced collagen deposition, and lower expression of injury and fibrosis markers. Weaker but similar tendencies were observed in transgenic AZGP1 overexpressing mice. Higher AZGP1 levels led to a significant reduction in stress-induced accumulation of tubular lipid droplets, which was paralleled by improved expression of key players in lipid metabolism and fatty acid oxidation. Together these data show beneficial effects of elevated AZGP1 levels in fibrotic kidney disease and highlight a novel link to tubular cell lipid metabolism, which might open up new opportunities for CKD treatment.

Expression of Recombinant Rat Secretable FNDC5 in Pichia Pastoris and Detection of Its Biological Activity

FNDC5 is the precursor of the myokine irisin proposed to exhibit favorable metabolic activity, including anti-obesity and anti-diabetes effects. The diversity of FNDC5 transcripts has been reported by several studies, but the role and existence of these transcripts are not well defined. In our previous study, a novel secretable FNDC5 (sFNDC5) isoform lacking the transmembrane region was found in rat INS-1 cells and multiple rat tissues. In the current study, we established a high-yield system for the expression and purification of sFNDC5 in Pichia pastoris, and functional investigations were undertaken using 3T3-L1 cells. We discovered that this new isoform has similar and even stronger biological functions than irisin, which may be due to its more complete structure without cleavage. Hence, we believe that sFNDC5, as the first identified readily secretable derivative, can better induce lipolysis and can potentially prevent obesity and related metabolic diseases.

The association of the adipokine zinc-alpha2-glycoprotein with non-alcoholic fatty liver disease and related risk factors: A comprehensive systematic review

BACKGROUND AND AIM

The adipokine zinc-alpha2-glycoprotein (ZAG), a multidisciplinary protein, is involved in lipid metabolism, glucose homeostasis and energy balance. Accumulating evidence demonstrates that the expression of ZAG is mainly downregulated in obesity and obesity-related conditions. In the present study, we assessed the association of ZAG with non-alcoholic fatty liver disease (NAFLD) and the related risk factors including obesity, metabolic factors and inflammatory parameters, with emphasis on potential mechanisms underlying these associations.

METHODS

PRISMA guidelines were followed in this review. Systematic searches were performed using the PubMed/Medline, ScienceDirect, Scopus, EMBASE, ProQuest and Google Scholar databases, up to August 2020 for all relevant published papers.

RESULTS

Out of 362 records screened, 34 articles were included in the final analysis. According to the studies reviewed here, ZAG appears to exert a protective effect against NAFLD by enhancing mRNA expression levels of peroxisome proliferator-activated receptor α (PPARα) and PPARγ, promoting mRNA expression levels of the lipolysis-related genes, reducing mRNA expression levels of the lipogenesis-related genes, increasing hepatic fatty acid oxidation, ameliorating hepatic steatosis, promoting the activity of brown adipose tissue and the expression of thermogenesis-related genes, modulating energy balance and glucose homeostasis, and elevating plasma levels of healthy adipokines such as adiponectin. ZAG can also be involved in the regulation of inflammatory responses by attenuation of the expression of pro-inflammatory and pro-fibrotic mediators.

CONCLUSION

According to the studies reviewed here, ZAG is suggested to be a promising therapeutic target for NAFLD. However, the favourable effects of ZAG need to be confirmed in prospective cohort studies.

Zinc-α2-Glycoprotein Knockout Influenced Genes Expression Profile in Adipose Tissue and Decreased the Lipid Mobilizing After Dexamethasone Treatment in Mice

Zinc-α2-glycoprotein (ZAG), as an adipokine, plays an important role in lipid metabolism. However, its influence on whole gene expression profile in adipose tissue is not known. Under stress condition, how ZAG affects the lipid metabolism is also unclear. Therefore, in this study ZAG systemic knockout (KO) mice were used as a model to reveal the genes expression profile in visceral fat tissues of ZAG KO mice and wild-type mice by genome-wide microarray screening. Then dexamethasone (DEX) was used to explore the effect of ZAG deletion on body fat metabolism under stress. Our results showed that 179 genes were differentially expressed more than 1.5 times between ZAG KO mice and wild type mice, of which 26 genes were upregulated dramatically and 153 genes were significantly downregulated. Under DEX simulated stress, ZAG systemic knockout in vivo resulted in a markedly decrease of triglycerides (TG) and nonesterified fatty acid (NEFA) content in in plasma. Similarly, for lipid catabolism, ZAG KO led to a significant increase of phosphorylated HSL (p-HSL) protein and a rising tendency of adipose triglyceride lipase (ATGL) protein relative to those of the DEX group. For lipid anabolism, fatty acid synthase (FAS) and adiponectin protein expression in visceral fat rose notably in ZAG KO mice after DEX treatment. In conclusion, ZAG knockout can affect the gene expression profile of adipose tissue, reduce elevated TG and NEFA levels in plasma, and alter lipid metabolism under DEX treatment. These findings provide new insights into the mechanism of lipid metabolic disorders in response to stress.

Rosiglitazone ameliorates palmitic acid-induced endoplasmic reticulum stress and steroidogenic capacity in granulosa cells

Granulosa cells play essential roles in follicular development, oocyte maturation and sex hormone secretion. The exposure of granulosa cells to palmitic acid (PA), the main component of dietary saturated fat, inhibits cell viability. However, the mechanism underlying PA-induced cytotoxicity in granulosa cells has not been deeply investigated. Rosiglitazone (RSG) is a member of the thiazolidinedione family and is reported to protect cells from cytotoxicity and endoplasmic reticulum (ER) stress in other cell types, but whether RSG protects granulosa cells remain unknown. In this study, KGN cell line and primary granulosa cells were used as models of granulosa cells to explore the effects of PA and RSG and the underlying mechanisms. The results showed that PA inhibits cell viability and estradiol secretion through inducing ER stress and cAMP/PKA/CREB pathway. CCAAT/enhancer-binding protein homologous protein (CHOP), an ER stress marker, was demonstrated to participate in PA-induced cytotoxicity. RSG treatment rescued granulosa cells from PA-induced cell death and ER stress. Moreover, RSG was identified to ameliorate ER stress induced by tunicamycin in granulosa cells. In addition, RSG treatment rescued granulosa cells from PA-induced decrease of estrogen secretion by cAMP/PKA/CREB pathway. In conclusion, RSG can protect granulosa cells against PA-induced cytotoxicity by inhibiting ER stress, and can recover steroidogenic capacity, indicating a potential use of RSG in the treatment of granulosa cell dysfunction.

Seizure-induced impairment in neuronal ketogenesis: Role of zinc-α2-glycoprotein in mitochondria

Ketone bodies (KBs) were known to suppress seizure. Untraditionally, neurons were recently reported to utilize fatty acids and produce KBs, but the effect of seizure on neuronal ketogenesis has not been researched. Zinc‐α2‐glycoprotein (ZAG) was reported to suppress seizure via unclear mechanism. Interestingly, ZAG was involved in fatty acid β‐oxidation and thus may exert anti‐epileptic effect by promoting ketogenesis. However, this promotive effect of ZAG on neuronal ketogenesis has not been clarified. In this study, we performed immunoprecipitation and mass spectrometry to identify potential interaction partners with ZAG. The mechanisms of how ZAG translocated into mitochondria were determined by quantitative coimmunoprecipitation after treatment with apoptozole, a heat shock cognate protein 70 (HSC70) inhibitor. ZAG level was modulated by lentivirus in neurons or adeno‐associated virus in rat brains. Seizure models were induced by magnesium (Mg²⁺)‐free artificial cerebrospinal fluid in neurons or intraperitoneal injection of pentylenetetrazole kindling in rats. Ketogenesis was determined by cyclic thio‐NADH method in supernatant of neurons or brain homogenate. The effect of peroxisome proliferator–activated receptor γ (PPARγ) on ZAG expression was examined by Western blot, quantitative real‐time polymerase chain reaction (qRT‐PCR) and chromatin immunoprecipitation qRT‐PCR. We found that seizure induced ketogenesis deficiency via a ZAG‐dependent mechanism. ZAG entered mitochondria through a HSC70‐dependent mechanism, promoted ketogenesis by binding to four β‐subunits of long‐chain L‐3‐hydroxyacyl‐CoA dehydrogenase (HADHB) and alleviated ketogenesis impairment in a neuronal seizure model and pentylenetetrazole‐kindled epileptic rats. Additionally, PPARγ activation up‐regulated ZAG expression by binding to promoter region of AZGP1 gene and promoted ketogenesis through a ZAG‐dependent mechanism.

Mechanism Underlying p-Coumaric Acid Alleviation of Lipid Accumulation in Palmitic Acid-Treated Human Hepatoma Cells

The protective effect and mechanism of action of p-coumaric acid for alleviating palmitic acid (PA)-induced hepatocyte injury were investigated using a PA-induced human hepatoma cell (HepG2)-based hepatocellular injury model and MTT cell viability determinations. Additionally, reduced glutathione content and catalase activity were detected using commercial kits, while intracellular lipid accumulation and total triglyceride content were measured using Oil Red O staining and a triglyceride quantification kit, respectively. Meanwhile, levels of proteins (fatty acid synthase, sterol regulatory element-binding protein-1, stearoyl-CoA desaturase-1) and proliferator-activated receptor-α mRNA were determined using western blotting and real-time quantitative polymerase chain reaction, respectively. After p-coumaric acid targets were identified using network pharmacological analysis, cyclooxygenase-2 (COX-2) expression was assessed via western blotting, while prostaglandin E2 accumulation was measured via an enzyme-linked immunosorbent assay. Notably, PA-treated hepatocytes exhibited increased viability (87.3 ± 2.2% vs 65.5 ± 2.5% for untreated cells), with reduced intracellular lipid accumulation reflecting promotion of lipolysis and fatty acid β-oxidation; this protective effect may depend on inhibition of both PA-induced HepG2 cell COX-2 expression and PGE2 accumulation.

Zinc-α2-glycoprotein promotes browning of white adipose tissue in cold-exposed male mice

The promotion of white adipose tissue (WAT) browning has emerged as a promising therapeutic target to increase energy expenditure and decrease weight gain. Zinc-α2-glycoprotein (ZAG) is a newly identified adipokine that regulates lipid metabolism. It shows high expression in brown adipose tissue (BAT), but whether ZAG plays a key role in the browning of white adipose tissue is still largely unclear. In the present study, we explored the relationship between ZAG and the browning of WAT in cold-exposed ZAG knockout (KO) mice and 3T3-L1 adipocytes with overexpressed ZAG. The results showed that cold stress induced marked accumulation of ZAG in wild type (WT) mice. Additionally, ZAG deficiency inhibited the loss of body weight and adipose tissue weight in cold stressed mice. ZAG KO mice were resistant to cold-induced expression of browning markers and energy metabolism in WAT. Furthermore, replenishment ZAG plasmid improved the reduction in cold-induced browning of WAT in ZAG KO mice. In vitro, ZAG overexpression promoted browning and mitochondrial biogenesis and increased the expression of β3-AR and P-P38 in 3T3-L1 adipocytes. These findings demonstrate that ZAG can promote the browning of white adipose tissue and can serve as a potential therapeutic target for treating metabolic diseases such as obesity.

Sesamol Alleviates Obesity-Related Hepatic Steatosis via Activating Hepatic PKA Pathway

This study aimed to investigate the effect of sesamol (SEM) on the protein kinase A (PKA) pathway in obesity-related hepatic steatosis treatment by using high-fat diet (HFD)-induced obese mice and a palmitic acid (PA)-treated HepG2 cell line. SEM reduced the body weight gain of obese mice and alleviated related metabolic disorders such as insulin resistance, hyperlipidemia, and systemic inflammation. Furthermore, lipid accumulation in the liver and HepG2 cells was reduced by SEM. SEM downregulated the gene and protein levels of lipogenic regulator factors, and upregulated the gene and protein levels of the regulator factors responsible for lipolysis and fatty acid β-oxidation. Meanwhile, SEM activated AMP-activated protein kinase (AMPK), which might explain the regulatory effect of SEM on fatty acid β-oxidation and lipogenesis. Additionally, the PKA-C and phospho-PKA substrate levels were higher after SEM treatment. Further research found that after pretreatment with the PKA inhibitor, H89, lipid accumulation was increased even with SEM administration in HepG2 cells, and the effect of SEM on lipid metabolism-related regulator factors was abolished by H89. In conclusion, SEM has a positive therapeutic effect on obesity and obesity-related hepatic steatosis by regulating the hepatic lipid metabolism mediated by the PKA pathway.

Serum Zinc-α2-Glycoprotein Levels in Patients with or without Coronary Artery Disease in Chinese North Population

Coronary artery disease (CAD), the leading cause of morbidity and mortality, has imposed huge health and economic burdens globally. Zinc-α2-glycoprotein (ZAG) is a novel adipokine. Increasing evidence suggests the close relationship between serum ZAG levels and various cardiometabolic risk factors. However, the relationship between serum ZAG levels and CAD is still not fully clarified. We conducted this study to evaluate serum ZAG levels and its association with cardiovascular risk factors. A total of 129 patients with CAD, 99 patients with noncoronary artery disease (NCAD), and 121 controls were recruited in this retrospective study. CAD (coronary artery stenosis ≥50%) or NCAD (coronary artery stenosis <50%) patients who underwent coronary angiography were diagnosed according to the American Heart Association criteria. Serum ZAG levels were determined via commercial enzyme-linked immunosorbent assay (ELISA) kits. The results showed that serum ZAG levels in CAD and NCAD groups were significantly decreased when compared with those in the control group. Multiple stepwise regression analysis revealed that the grouping variable (control, NCAD, and CAD) was an independent determinant of serum ZAG levels (β = -0.328, P < 0.001) after controlling other confounding factors. Further multivariate ordinary logistic regression analysis demonstrated that the risk of grouping at one level higher in subjects with the lowest tertile of ZAG levels was 2.28-fold higher than those with the highest tertile levels (OR = 3.281, 95% CI 1.782-6.038, P < 0.001). The receiver-operating characteristic (ROC) curve analysis showed that serum ZAG could distinguish CAD patients (AUC = 0.706, 95% CI, 0.643-0.770, P < 0.05), NCAD patients (AUC = 0.673, 95% CI, 0.602-0.743, P < 0.05), and NCAD and CAD patients (AUC = 0.692, 95% CI, 0.633-0.750, P < 0.05) from controls. In conclusion, serum ZAG levels were significantly decreased in NCAD/CAD patients. The decreased serum ZAG levels were independently associated with the presence of NCAD/CAD. ZAG might serve as a candidate diagnostic biomarker for NCAD/CAD.

Zinc-α2-glycoprotein 1 attenuates non-alcoholic fatty liver disease by negatively regulating tumour necrosis factor-α

BACKGROUND

Zinc-α2-glycoprotein 1 (AZGP1) plays important roles in metabolism-related diseases. The underlying molecular mechanisms and therapeutic effects of AZGP1 remain unknown in non-alcoholic fatty liver disease (NAFLD).

AIM

To explore the effects and potential mechanism of AZGP1 on NAFLD in vivo and in vitro.

METHODS

The expression of AZGP1 and its effects on hepatocytes were examined in NAFLD patients, CCl₄-treated mice fed a high fat diet (HFD), and human LO2 cells.

RESULTS

AZGP1 levels were significantly decreased in liver tissues of NAFLD patients and mice. AZGP1 knockdown was found to activate inflammation; enhance steatogenesis, including promoting lipogenesis [sterol regulatory element-binding protein (SREBP)-1c, liver X receptor (LXR), fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and stearoyl CoA desaturase 1 (SCD)-1], increasing lipid transport and accumulation [fatty acid transport protein (FATP), carnitine palmitoyl transferase (CPT)-1A, and adiponectin], and reducing fatty acid β-oxidation [farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR)-α]; accelerate proliferation; and reverse apoptosis in LO2 cells. AZGP1 overexpression (OV-AZGP1) had the opposite effects. Furthermore, AZGP1 alleviated NAFLD by blocking TNF-α-mediated inflammation and intracellular lipid deposition, promoting proliferation, and inhibiting apoptosis in LO2 cells. Finally, treatment with OV-AZGP1 plasmid dramatically improved liver injury and eliminated liver fat in NAFLD mice.

CONCLUSION

AZGP1 attenuates NAFLD with regard to ameliorating inflammation, accelerating lipolysis, promoting proliferation, and reducing apoptosis by negatively regulating TNF-α. AZGP1 is suggested to be a novel promising therapeutic target for NAFLD.

Adipokine zinc-α2-glycoprotein alleviates lipopolysaccharide-induced inflammatory responses through the β3-AR/PKA/CREB pathway

Humans and animals frequently experience dysmetabolism induced by inflammation. Zinc-α2-glycoprotein (ZAG), a newly identified adipokine, is potentially involved in lipid metabolism. Our previous study revealed that the ZAG content increased after lipopolysaccharide (LPS) treatment. To clarify ZAG's possible effects on inflammatory responses and lipid metabolism, we used gene overexpression and knockout mice as models to investigate the function of ZAG during inflammation. The results showed that LPS increased plasma triglyceride, non-esterified fatty acid and hepatic triglyceride, while ZAG overexpression decreased these effects. Furthermore, ZAG overexpression weakened inflammatory responses, suppressed lipogenesis, and improved mitochondrial function during inflammation. ZAG overexpression also increased β3-adrenoreceptor, protein kinase A, and phosphorylated cyclic adenosine monophosphate-response element binding protein (CREB), promoted the combination of CREB and CREB-binding protein (CBP), and competitively inhibited the combination of nuclear factor-κB and CBP. After ZAG knockout, LPS-induced the hyperlipidemia worsened. ZAG knockout aggravated inflammatory responses, promoted lipogenesis, and weakened mitochondrial function during inflammation. ZAG knockout also decreased β3-adrenoreceptor and protein kinase A. The present study demonstrated that ZAG alleviated lipid metabolism disorders by weakening inflammatory responses. The β3-adrenoreceptor/protein kinase A/CREB pathway mediated the effects of ZAG on inflammation. These results will provide new insight for research on anti-inflammation.

Berberine attenuates sodium palmitate-induced lipid accumulation, oxidative stress and apoptosis in grass carp(Ctenopharyngodon idella)hepatocyte in vitro

The objective of this work was to investigate the effect of berberine (BBR) on the Cell viability, lipid accumulation, apoptosis, cytochrome c, caspase-9 and caspase-3 in lipid accumulation-hepatocytes induced by sodium palmitate in vitro. The lipid accumulation-hepatocytes (induced by 0.5 mM sodium palmitate for 24 h) were treated with 5 μM berberine for 12 h. Then, the Cell viability, intracellular triglyceride (TG) content, lipid peroxide (LPO), malonaldehyde (MDA) content, cytochrome c, caspase-9, caspase-3 and apoptosis were detected. Sodium palmitate decreased Cell viability and increased intracellular TG content, lipid droplet accumulation, LPO and MDA concentrations, caused caspase-3 and caspase-9 activation, then led to apoptosis accompanied by cytochrome c release from mitochondria into the cytoplasm. Beberine could improve intracellular lipid droplet accumulation and oxidative stress, while reduce apoptosis induced by sodium palmitate.

Serum zinc-α2-glycoprotein levels are elevated and correlated with thyroid hormone in newly diagnosed hyperthyroidism

BACKGROUND

Zinc-α2-glycoprotein (ZAG) is a recently novel lipolytic adipokine implicated in regulation of glucose and lipid metabolism in many metabolic disorders. In vitro and animal studies suggest that thyroid hormones (TH) up-regulates ZAG production in hepatocytes. However, there is no data evaluating the possible relationship between ZAG and TH in a human model of hyperthyroidism. The objective of the present study is to assess the association of serum ZAG levels with TH and lipid profile in patients with hyperthyroidism before and after methimazole treatment.

METHODS

A total of 120 newly diagnosed overt hyperthyroidism and 122 healthy control subjects were recruited. Of them, 39 hyperthyroidism patients were assigned to receive methimazole treatment as follow-up study for 2 months.

RESULTS

The clinical consequence showed that serum ZAG levels were elevated in patients with hyperthyroidism (P < 0.01). Adjust for age, gender and BMI, serum ZAG levels were positively related with serum free T3 (FT3), free T4 (FT4) levels and negatively correlated with serum total cholesterol (TC), low density lipoprotein cholesterol (LDLC) levels in hyperthyroidism subjects (all P < 0.01). After methimazole treatment, serum ZAG levels were decreased and the decline was associated with decreased FT3, FT4 and increased TC levels (all P < 0.001).

CONCLUSION

We conclude that ZAG may be involved in the pathogenesis of lipid metabolism disorder in patients with hyperthyroidism.

TRIAL REGISTRATION

ChiCTR-ROC-17012943 . Registered 11 October 2017, retrospectively registered.

Effects of Azgp1-/-on mammary gland, adipose tissue and liver gene expression and milk lipid composition in lactating mice

The expression of Azgp1 gene, an adipokine involved in the mobilization of body reserves, was observed in mammary gland of ruminants. Its regulation by different dietary conditions suggests a potential role in the mechanisms controlling the composition of milk fat. The aim of this study was to evaluate the role of Azgp1 during lactation. Azgp1^-/- mice were compared to wild-type to determine its effects on milk fatty acid composition and offspring growth. To determine its effects on mammary gland, adipose tissue and liver gene expression, gene expression was analyzed using RT-qPCR via TLDA analyses. The body weight of Azgp1^-/- mothers was slightly higher after parturition and at 10 days of lactation compared to the wild type. The milk polyunsaturated fatty acid content was increased in Azgp1^-/- mice. Among the 40 genes studied, Azgp1^-/- modified the expression of 9, 10 and 3 genes in mammary gland, adipose tissue and liver, respectively. These genes, involved in fatty acid synthesis, transport and triglyceride synthesis, were downregulated in Azgp1^-/- mice showing a particularity during lactation. Changes in mammary gland gene expression may explain the modifications observed in milk fatty acid composition. This study supports a role of Azgp1 on lipid metabolism, in particular in mammary gland, during lactation function.

Expression and Function of Zinc-α2-Glycoprotein

Zinc-α2-glycoprotein (ZAG), encoded by the AZGP1 gene, is a major histocompatibility complex I molecule and a lipid-mobilizing factor. ZAG has been demonstrated to promote lipid metabolism and glucose utilization, and to regulate insulin sensitivity. Apart from adipose tissue, skeletal muscle, liver, and kidney, ZAG also occurs in brain tissue, but its distribution in brain is debatable. Only a few studies have investigated ZAG in the brain. It has been found in the brains of patients with Krabbe disease and epilepsy, and in the cerebrospinal fluid of patients with Alzheimer disease, frontotemporal lobe dementia, and amyotrophic lateral sclerosis. Both ZAG protein and AZGP1 mRNA are decreased in epilepsy patients and animal models, while overexpression of ZAG suppresses seizure and epileptic discharges in animal models of epilepsy, but knowledge of the specific mechanism of ZAG in epilepsy is limited. In this review, we summarize the known roles and molecular mechanisms of ZAG in lipid metabolism and glucose metabolism, and in the regulation of insulin sensitivity, and discuss the possible mechanisms by which it suppresses epilepsy.

Rosiglitazone ameliorates palmitic acid-induced cytotoxicity in TM4 Sertoli cells

The Sertoli cell is the only somatic cell within the seminiferous tubules, and is vital for testis development and spermatogenesis. Rosiglitazone (RSG) is a member of the thiazolidinedione family and is a peroxisome proliferator-activated receptor-γ (PPARγ) agonist. It has been reported that RSG protects various types of cells from fatty acid-induced damage. However, whether RSG serves a protective role in Sertoli cells against palmitic acid (PA)-induced toxicity remains to be elucidated. Therefore, the aim of the present study was to investigate the effect of RSG on PA-induced cytotoxicity in Sertoli cells. MTT assay and Oil Red O staining revealed that RSG ameliorated the PA-induced decrease in TM4 cell viability, which was accompanied by an alleviation of PA-induced lipid accumulation in cells. In primary mouse Sertoli cells, RSG also showed similar protective effects against PA-induced lipotoxicity. Knockdown of PPARγ verified that RSG exerted its protective role in TM4 cells through a PPARγ-dependent pathway. To evaluate the mechanism underlying the protective role of RSG on PA-induced lipotoxicity, the present study analyzed the effects of RSG on PA uptake, and the expression of genes associated with both fatty acid oxidation and triglyceride synthesis. The results demonstrated that although RSG did not affect the endocytosis of PA, it significantly elevated the expression of carnitine palmitoyltransferase (CPT)-1A, a key enzyme involved in fatty acid oxidation, which indicated that the protective effect of RSG may have an important role in fatty acid oxidation. On the other hand, the expression of CPT1B was not affected by RSG. Moreover, the expression levels of diacylglycerol O-acyltransferase (DGAT)-1 and DGAT2, both of which encode enzymes catalyzing the synthesis of triglycerides, were not suppressed by RSG. The results indicated that RSG reduced PA-induced lipid accumulation by promoting fatty acid oxidation mediated by CPT1A. The effect of RSG in protecting cells from lipotoxicity was also found to be specific to Sertoli cells and hepatocytes, and not to other cell types that do not store excess lipid in large quantities, such as human umbilical vein endothelial cells. These findings provide insights into the cytoprotective effects of RSG on Sertoli cells and suggest that PPARγ activation may be a useful therapeutic method for the treatment of Sertoli cell dysfunction caused by dyslipidemia.

Increased serum levels of S100A1, ZAG, and adiponectin in cachectic patients with COPD

Background

COPD is a common irreversible obstructive airway disease. S100A1, ZAG, and adiponectin are important regulators of energy metabolism and body weight. Therefore, the aim of this study was to assess resting metabolic rate (RMR) and its association with serum levels of S100A1, ZAG, and adiponectin in cachectic and noncachectic COPD patients.

Patients and methods

Ninety men with COPD, aged 40–70 years, were enrolled in the study. Patients were divided into the following two groups based on the unintentional weight loss of .7.5% in previous 6 months: noncachectic (n=45) and cachectic (n=45). The groups were matched based on age and body mass index (BMI). RMR was measured by indirect calorimetry method. Anthropometric indices and body composition were also measured. Serum levels of S100A1, ZAG, and adiponectin were measured by ELISA.

Results

Cachectic patients had significantly higher RMR than controls (P<0.001). Serum levels of ZAG, S100A1, and adiponectin were significantly higher in the cachexia group (P<0.0001). RMR was not significantly associated with S100A1, ZAG, and adiponectin levels. However, weight loss of patients was significantly associated with serum levels of ZAG and adiponectin (both, β=0.22, P=0.03). Strong and positive association were found between the serum levels of S100A1 and ZAG (β=0.88, P<0.0001), S100A1 and adiponectin (β=0.86, P<0.0001), and also ZAG and adiponectin (β=0.83, P<0.0001).

Conclusion

The potential role of these factors in the wasting process is considerable. Also, the association between serum levels of S100A1, ZAG, and adiponectin represents that these three proteins are probably related to specific functions.

Crosstalk between zinc and free fatty acids in plasma

In mammalian blood plasma, serum albumin acts as a transport protein for free fatty acids, other lipids and hydrophobic molecules including neurodegenerative peptides, and essential metal ions such as zinc to allow their systemic distribution. Importantly, binding of these chemically extremely diverse entities is not independent, but linked allosterically. One particularly intriguing allosteric link exists between free fatty acid and zinc binding. Albumin thus mediates crosstalk between energy status/metabolism and organismal zinc handling. In recognition of the fact that even small changes in extracellular zinc concentration and speciation modulate the function of many cell types, the albumin-mediated impact of free fatty acid concentration on zinc distribution may be significant for both normal physiological processes including energy metabolism, insulin activity, heparin neutralisation, blood coagulation, and zinc signalling, and a range of disease states, including metabolic syndrome, cardiovascular disease, myocardial ischemia, diabetes, and thrombosis.

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Serum albumin binds and transports both free fatty acids and Zn²⁺ ions

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Elevated plasma free fatty acids impair Zn²⁺ binding by albumin through an allosteric mechanism

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The resulting changes in plasma zinc speciation are thought to impact blood coagulation and may promote thrombosis

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Increased free Zn²⁺ may lead to enhanced zinc export from plasma and dysregulation of zinc homeostasis in multiple tissues

p53 cooperates with SIRT6 to regulate cardiolipin de novo biosynthesis

The tumor suppressor p53 has critical roles in regulating lipid metabolism, but whether and how p53 regulates cardiolipin (CL) de novo biosynthesis is unknown. Here, we report that p53 physically interacts with histone deacetylase SIRT6 in vitro and in vivo, and this interaction increases following palmitic acid (PA) treatment. In response to PA, p53 and SIRT6 localize to chromatin in a p53-dependent manner. Chromatin p53 and SIRT6 bind the promoters of CDP-diacylglycerol synthase 1 and 2 (CDS1 and CDS2), two enzymes required to catalyze CL de novo biosynthesis. Here, SIRT6 serves as a co-activator of p53 and effectively recruits RNA polymerase II to the CDS1 and CDS2 promoters to enhance CL de novo biosynthesis. Our findings reveal a novel, cooperative model executed by p53 and SIRT6 to maintain lipid homeostasis.

Hexanoic, Octanoic and Decanoic Acids Promote Basal and Insulin-Induced Phosphorylation of the Akt-mTOR Axis and a Balanced Lipid Metabolism in the HepG2 Hepatoma Cell Line

Metabolic illnesses such as non-alcoholic fatty liver disease (NAFLD) are in constant increase worldwide. Highly consumed long chain fatty acids (LCFA) are among the most obesogenic and steatogenic nutrients. Hepatic steatosis is associated with several complications such as insulin resistance. Growing evidence points to medium chain fatty acids (MCFA), more efficiently oxidized than LCFA, as a promising dietary alternative against NAFLD. However, reports on the hepatic effects of MCFA are sometimes conflicting. In this study we exposed HepG2 cells, a human hepatocellular model, to 0.25 mM of hexanoic (C6), or octanoic (C8), and decanoic (C10) acids separately or in a C8 + C10 equimolar mix reflecting commercially available MCFA-rich oils. We found that C6, a poorly studied MCFA, as well as C8 and C10 did not provoke the deleterious lipid anabolism runaway typically induced by LCFA palmitate. MCFA tended, instead, to promote a balanced metabolic profile and were generally non-cytotoxic. Accordingly, mitochondrial integrity was mostly preserved following MCFA treatment. However, treatments with C8 induced a mitochondrial membrane potential decrease, suggesting prolonged exposure to this lipid could be problematic. Finally, MCFA treatments maintained optimal insulin sensitivity and even fostered basal and insulin-dependent phosphorylation of the Akt-mTOR pathway. Overall, MCFA could constitute an effective nutritional tool to manage liver steatosis and hepatic insulin resistance.

Zinc alpha2 glycoprotein protects against obesity-induced hepatic steatosis

BACKGROUND/AIM

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, impaired insulin sensitivity, and chronic low-grade inflammation. Our previous studies indicated that zinc alpha2 glycoprotein (ZAG) alleviates palmitate (PA)-induced intracellular lipid accumulation in hepatocytes. This study is to further characterize the roles of ZAG on the development of hepatic steatosis, insulin resistance (IR), and inflammation.

METHODS

ZAG protein levels in the livers of NAFLD patients, high-fat diet (HFD)-induced or genetically (ob/ob) induced obese mice, and in PA-treated hepatocytes were determined by western blotting. C57BL/6J mice injected with an adenovirus expressing ZAG were fed HFD for indicated time to induce hepatic steatosis, IR, and inflammation, and then biomedical, histological, and metabolic analyses were conducted to identify pathologic alterations in these mice. The molecular mechanisms underlying ZAG-regulated hepatic steatosis were further explored and verified in mice and hepatocytes.

RESULTS

ZAG expression was decreased in NAFLD patient liver biopsy samples, obese mice livers, and PA-treated hepatocytes. Simultaneously, ZAG overexpression alleviated intracellular lipid accumulation via upregulating adiponectin and lipolytic genes (FXR, PPARα, etc.) while downregulating lipogenic genes (SREBP-1c, LXR, etc.) in obese mice as well as in cultured hepatocytes. ZAG improved insulin sensitivity and glucose tolerance via activation of IRS/AKT signaling. Moreover, ZAG significantly inhibited NF-ĸB/JNK signaling and thus resulting in suppression of obesity-associated inflammatory response in hepatocytes.

CONCLUSIONS

Our results revealed that ZAG could protect against NAFLD by ameliorating hepatic steatosis, IR, and inflammation.

Effects of adipokine zinc-α2-glycoprotein on adipose tissue metabolism after dexamethasone treatment

Zinc-α2-glycoprotein (ZAG) has been demonstrated to play a role in stimulating lipid mobilization under normal conditions. However, further studies are required to determine whether ZAG overexpression can alleviate the reduction in plasma lipid levels under stress conditions. In the present study, we investigated the effects of ZAG on lipometabolism in white adipose tissue (WAT) after dexamethasone (DEX) stimulation using C57BL/6 male mice as the experimental models. Transcript and protein levels of genes associated with the β-adrenoreceptor (β-AR)/cyclic adenosine monophosphate/protein kinase a (PKA) pathway, lipid mobilization, and energy metabolism were determined by quantitative real-time polymerase chain reaction and Western blotting. Plasma levels of nonesterified fatty acid (NEFA) were measured using an automatic biochemical analyzer. Results indicated that plasma NEFA levels were decreased in the DEX group, but NEFA levels were rescued by ZAG overexpression. ZAG overexpression resulted in the upregulation of β3-AR and phosphorylated PKA protein relative to those of the DEX group. Analysis of lipometabolism showed that protein levels of phosphorylated hormone-sensitive lipase was reduced upon DEX treatment but were restored by ZAG overexpression. For energy metabolism, ZAG significantly upregulated the protein expression of carnitine palmitoyltransferase1a and cytochrome c oxidase subunit 1 relative to those of the DEX group. In conclusion, ZAG could alleviate DEX-induced decrease in plasma NEFA levels and this could be associated with the promoting lipid mobilization in WAT.