Cholesterol sulfate and cholesterol sulfotransferase inhibit gluconeogenesis by targeting hepatocyte nuclear factor 4α

Sulfotransferase 1C2 Increases Mitochondrial Respiration by Converting Mitochondrial Membrane Cholesterol to Cholesterol Sulfate

HYPOTHESIS

In this communication, we test the hypothesis that sulfotransferase 1C2 (SULT1C2, UniProt accession no. Q9WUW8) can modulate mitochondrial respiration by increasing state-III respiration.

METHODS AND RESULTS

Using freshly isolated mitochondria, the addition of SULT1C2 and 3-phosphoadenosine 5 phosphosulfate (PAPS) results in an increased maximal respiratory capacity in response to the addition of succinate, ADP, and rotenone. Lipidomics and thin-layer chromatography of mitochondria treated with SULT1C2 and PAPS showed an increase in the level of cholesterol sulfate. Notably, adding cholesterol sulfate at nanomolar concentration to freshly isolated mitochondria also increases maximal respiratory capacity. In vivo studies utilizing gene delivery of SULT1C2 expression plasmids to kidneys result in increased mitochondrial membrane potential and confer resistance to ischemia/reperfusion injury. Mitochondria isolated from gene-transduced kidneys have elevated state-III respiration as compared with controls, thereby recapitulating results obtained with mitochondrial fractions treated with SULT1C2 and PAPS.

CONCLUSION

SULT1C2 increases mitochondrial respiratory capacity by modifying cholesterol, resulting in increased membrane potential and maximal respiratory capacity. This finding uncovers a unique role of SULT1C2 in cellular physiology and extends the role of sulfotransferases in modulating cellular metabolism.

The role of adhesion molecules in osteocalcin-induced effects on glucose and lipid metabolism in adipocytes

Recent findings suggest that uncarboxylated osteocalcin (GluOC) promotes glucose and lipid metabolism via its putative receptor GPRC6A; however, its direct effect on adipocytes remains elusive. In this study, we elucidated the effects of GluOC on adipocytes, with an emphasis on the role of cell adhesion molecules. We determined that GluOC promoted the expression of adipocyte adhesion molecule (ACAM) and its transcription factor Krüppel-like factor 4 and enhanced the cortical actin filament assembly, which ameliorated lipid droplet hypertrophy. Additionally, GluOC upregulated the expression of integrin αVβ3 and activation of focal adhesion kinase (FAK) and prevented insulin receptor substrate 1 (IRS1) degradation by inhibiting the ubiquitin-proteasome system via the FAK-PLC-PKC axis, which activated IRS1-Akt-mediated glucose transporter 4 (GLUT4) transport. Furthermore, we showed that GluOC elevated the expression of the insulin-independent glucose transporters GLUT1 and GLUT8, which facilitated insulin stimulation-independent glucose transport. The GluOC-induced activation of integrin αVβ3 signaling promoted microtubule assembly, which improved glucose and lipid metabolism via its involvement in intracellular vesicular transport. GluOC treatment also suppressed collagen type 1 formation, which might prevent adipose tissue fibrosis in obese individuals. Overall, our results imply that GluOC promotes glucose and lipid metabolism via ACAM, integrin αVβ3, and GLUT1 and 8 expression, directly affecting adipocytes.

Sulfotransferase 2B1b, Sterol Sulfonation, and Disease

The primary function of human sulfotransferase 2B1b (SULT2B1b) is to sulfonate cholesterol and closely related sterols. SULT2B1b sterols perform a number of essential cellular functions. Many are signaling molecules whose activities are redefined by sulfonation-allosteric properties are switched "on" or "off," agonists are transformed into antagonists, and vice versa. Sterol sulfonation is tightly coupled to cholesterol homeostasis, and sulfonation imbalances are causally linked to cholesterol-related diseases including certain cancers, Alzheimer disease, and recessive X-linked ichthyosis-an orphan skin disease. Numerous studies link SULT2B1b activity to disease-relevant molecular processes. Here, these multifaceted processes are integrated into metabolic maps that highlight their interdependence and how their actions are regulated and coordinated by SULT2B1b oxysterol sulfonation. The maps help explain why SULT2B1b inhibition arrests the growth of certain cancers and make the novel prediction that SULT2B1b inhibition will suppress production of amyloid β (Aβ) plaques and tau fibrils while simultaneously stimulating Aβ plaque phagocytosis. SULT2B1b harbors a sterol-selective allosteric site whose structure is discussed as a template for creating inhibitors to regulate SULT2B1b and its associated biology. SIGNIFICANCE STATEMENT: Human sulfotransferase 2B1b (SULT2B1b) produces sterol-sulfate signaling molecules that maintain the homeostasis of otherwise pro-disease processes in cancer, Alzheimer disease, and X-linked ichthyosis-an orphan skin disease. The functions of sterol sulfates in each disease are considered and codified into metabolic maps that explain the interdependencies of the sterol-regulated networks and their coordinate regulation by SULT2B1b. The structure of the SULT2B1b sterol-sensing allosteric site is discussed as a means of controlling sterol sulfate biology.

LC/MS-Based Untargeted Metabolomics Analysis in Women with Morbid Obesity and Associated Type 2 Diabetes Mellitus

Obesity is a chronic and complex disease, with an increasing incidence worldwide that is associated with metabolic disorders such as type 2 diabetes mellitus (T2DM). Thus, it is important to determine the differences between metabolically healthy obese individuals and those with metabolic disorders. The aim of this study was to perform an untargeted metabolomics assay in women with morbid obesity (MO) compared to a normal weight group, and to differentiate the metabolome of these women with MO who present with T2DM. We carried out a liquid chromatography-mass spectrometry-based untargeted metabolomics assay using serum samples of 209 Caucasian women: 73 with normal weight and 136 with MO, of which 71 had T2DM. First, we found increased levels of choline and acylglycerols and lower levels of bile acids, steroids, ceramides, glycosphingolipids, lysophosphatidylcholines, and lysophosphatidylethanolamines in MO women than in the control group. Then, in MO women with T2DM, we found increased levels of glutamate, propionyl-carnitine, bile acids, ceramides, lysophosphatidylcholine 14:0, phosphatidylinositols and phosphoethanolamines, and lower levels of Phe-Ile/Leu. Thus, we found metabolites with opposite trends of concentration in the two metabolomic analyses. These metabolites could be considered possible new factors of study in the pathogenesis of MO and associated T2DM in women.

Quercetin ameliorates hepatic fat accumulation in high-fat diet-induced obese mice via PPARs

As a natural pigment in food, quercetin possesses multiple biological activities and plays a crucial role in regulating metabolic syndrome. Herein, we aim to explore the potential mechanism of quercetin to ameliorate hepatic fat accumulation. In vivo experiments showed that quercetin significantly relieved inflammation response by decreasing the serum TNF-α and IL-6 levels and also improved high-fat diet-induced hepatic steatosis without other organ injuries. Quercetin can effectively reduce lipid aggregation and down-regulate the protein expression of PCK1 in HepG2 cells induced by oleic acid and palmitic acid, indicating that inhibiting gluconeogenesis leads to hepatic fat accumulation reduction. Furthermore, molecular docking results suggested that quercetin can bind to both PPARα and PPARγ, with an even more potent binding affinity than indeglitazar, a pan-agonist of PPARs. In conclusion, quercetin may regulate gluconeogenesis to ameliorate hepatic fat accumulation via targeting PPARα/γ.

Amelioration of cholesterol sulfate for lead-induced CTX cell apoptosis based on BDNF signaling pathway mediated cholesterol metabolism

Lead (Pb), as a deleterious heavy metal, ubiquitously exists in environment and industry, which engenders multi-organ disfunction, especially the brain of infants who are vulnerable to attack from lead-induced neurotoxicity. Although cholesterol sulfate (CS) is crucial constituent of cell membranes and precursor of neurosteroids, which maintains the function and survival of neurons, the role of CS in lead-induced neurological damage still remains incomplete. In this work, Rat Brain Astrocytes cell line (CTX cells) was applied into exploration that protective effects of CS on CTX cell apoptosis induced by lead via the regulation of BDNF/TrkB signaling pathway mediated cholesterol metabolism. We found that CTX cells exposed to lead manifested apparent cytotoxicity, where the viability of CTX cells was significantly suppressed, accompanied with the elevation of apoptosis, in response to a trend towards increases in reactive oxygen species (ROS) production and pro-apoptotic protein Cleaved-caspase3, synchronized with the decline in anti-apoptotic protein Bcl-2. Moreover, accumulation of lead in CTX cells showed a dose-dependent increase, and meanwhile, decrements in cholesterol content occurred along with increase in lead exposure, in which expressions of cholesterol metabolism related proteins and transcriptions of its genes (SREBP2, LDLR, and HMGCR) were diminished. Furthermore, BDNF signaling pathway was obviously blocked after lead exposure, down-regulating expressions of proteins BDNF and TrkB. However, pretreatment with CS detoxified the negative impacts of lead-invoked CTX cell damage, acting as an effective remedy for apoptosis, imbalance of cholesterol metabolism and inhibition of BDNF signaling pathway. In addition, the relationship between BDNF signaling pathway and cholesterol metabolism was further verified, in which cholesterol metabolism related proteins and genes were promoted significantly after the activation of BDNF/TrkB signaling pathway using 7,8-Dihydroxyflavone (7,8-DHF), thereby detoxifying lead-induced CTX cell injury. However, the pretreatment of TrkB inhibitor ANA-12 offset the promotion of 7,8-DHF and ultimately inhibit cholesterol metabolism. Overall, our study demonstrated that CS could initiate the BDNF/TrkB signaling pathway, regulating the cholesterol metabolism against CTX cell apoptosis invoked by lead.

Cholesterol sulfate alleviates ulcerative colitis by promoting cholesterol biosynthesis in colonic epithelial cells

Cholesterol sulfate, produced by hydroxysteroid sulfotransferase 2B1 (SULT2B1), is highly abundant in the intestine. Herein, we study the functional role and underlying intestinal epithelial repair mechanisms of cholesterol sulfate in ulcerative colitis. The levels of cholesterol and cholesterol sulfate, as well as the expression of Sult2b1 and genes involved in cholesterol biosynthesis, are significantly higher in inflamed tissues from patients with ulcerative colitis than in intestinal mucosa from healthy controls. Cholesterol sulfate in the gut and circulation is mainly catalyzed by intestinal epithelial SULT2B1. Specific deletion of the Sult2b1 gene in the intestinal epithelial cells aggravates dextran sulfate sodium-induced colitis; however, dietary supplementation with cholesterol sulfate ameliorates this effect in acute and chronic ulcerative colitis in mice. Cholesterol sulfate promotes cholesterol biosynthesis by binding to Niemann-Pick type C2 protein and activating sterol regulatory element binding protein 2 in colonic epithelial cells, thereby alleviates ulcerative colitis. In conclusion, cholesterol sulfate contributes to the healing of the mucosal barrier and exhibits therapeutic efficacy against ulcerative colitis in mice.

New treatment strategies are required for ulcerative colitis. Here the authors show in mouse models that cholesterol sulfate, an endogenous active cholesterol derivative, contributes to the healing of the mucosal barrier by promoting cholesterol biosynthesis in colonic epithelial cells and exhibits therapeutic efficacy against ulcerative colitis.

Cholesterol Sulfate Exerts Protective Effect on Pancreatic β-Cells by Regulating β-Cell Mass and Insulin Secretion

Rational: Cholesterol sulfate (CS) is the most abundant known sterol sulfate in human plasma, and it plays a significant role in the control of metabolism and inflammatory response, which contribute to the pathogenesis of insulin resistance, β-cell dysfunction and the resultant development of diabetes. However, the role of CS in β-cells and its effect on the development of diabetes remain unknown. Here, we determined the physiological function of CS in pancreatic β-cell homeostasis.

Materials and Methods: Blood CS levels in streptozotocin (STZ)- or high-fat diet-induced diabetic mice and patients with type 1 or 2 diabetes were determined by LC-MS/MS. The impact of CS on β-cell mass and insulin secretion was investigated in vitro in isolated mouse islets and the β-cell line INS-1 and in vivo in STZ-induced diabetic mice. The molecular mechanism of CS was explored by viability assay, EdU incorporation analysis, flow cytometry, intracellular Ca²⁺ influx analysis, mitochondrial membrane potential and cellular ROS assays, and metabolism assay kits.

Results: Plasma CS levels in mice and humans were significantly elevated under diabetic conditions. CS attenuated diabetes in a low-dose STZ-induced mouse model. Mechanistically, CS promoted β-cell proliferation and protected β-cells against apoptosis under stressful conditions, which in turn preserved β-cell mass. In addition, CS supported glucose transporter-2 (GLUT2) expression and mitochondrial integrity, which then resulted in a less reactive oxygen species (ROS) generation and an increase in ATP production, thereby enabling insulin secretion machinery in the islets to function adequately.

Conclusion: This study revealed a novel dual role of CS in integrating β-cell survival and cell function, suggesting that CS might offer a physiologic approach to preserve β-cells and protect against the development of diabetes mellitus.

Absorption, Pharmacokinetics, Tissue Distribution, and Excretion Profiles of Sea Cucumber-Derived Sulfated Sterols in Mice

Sea cucumber-derived sulfated sterols exhibited more significant bioactivities compared to plant sterols due to the distinctive structure of the sulfate group at the C-3 position; however, their absorption, pharmacokinetics, tissue distribution, and excretion profiles are unknown, which limits the analysis of molecular mechanisms related to their unique activities. In this study, the absorption characteristics of sea cucumber sterols were determined by oral gavage administration, and their pharmacokinetics, excretion, and tissue distribution were studied by tail vein injection. The results showed that SS1 and SS2 reached the peak at 3 h (20.14 ± 1.2 μg/mL) and 4 h (13.32 ± 0.9 μg/mL) in serum, respectively, after oral gavage administration, suggesting the faster absorption rate of SS1 than SS2 due to the difference in the side-chain groups. Besides, lipid-containing food media improved the digestion and absorption rates of sea cucumber sterols. Moreover, SS1 exhibited a relatively longer duration of efficacy than SS2, and they were almost completely excreted within 9 h through urine. Additionally, sea cucumber sterols were found to be mainly accumulated in the liver (P < 0.05), followed by the kidney and spleen. These findings might provide a theoretical basis for the research and development of functional foods and nutraceuticals associated with sea cucumber sterols.

Measuring the health effects of food by metabolomics

Metabolomics of human biological fluids or tissues is used to discover markers for diseases by comparing the metabolome of the patients against healthy individuals. Ultimately, these markers can be used in drug discovery to determine how medications normalize (at least in part) the human metabolome at specific disease stages to homeostatic. Likewise, the health effects of food can be studied. Even metabolomics of the food can be combined with metabolomics of the treated patients to correlate compounds from food with measurable health effects from clinical studies. Various chemometric analyses of these metabolomics data are used to identify markers for diseases and to obtain evidence for health effects. This review discusses recent researches (published from 2013 to 2021) on whether specific dietary intervention to humans suffering from metabolic disorders may improve their pathological status. The scope is limited to those associated with major lifestyle diseases such as diabetes, obesity, and cardiovascular diseases, for which food is thought may have detrimental as well as beneficial effects on human health. It includes metabolites characterization of different biological samples such as the human serum/plasma, urine, saliva, feces, or ileal fluid. Whether the study results supported the claimed health benefits and whether the research was conducted with appropriate study design, was criticized.

25-Hydroxycholesterol 3-sulfate is an endogenous ligand of DNA methyltransferases in hepatocytes

The oxysterol sulfate, 25-hydroxycholesterol 3-sulfate (25HC3S), has been shown to play an important role in lipid metabolism, inflammatory response, and cell survival. However, the mechanism(s) of its function in global regulation is unknown. The current study investigates the molecular mechanism by which 25HC3S functions as an endogenous epigenetic regulator. To study the effects of oxysterols/sterol sulfates on epigenetic modulators, 12 recombinant epigenetic enzymes were used to determine whether 25HC3S acts as their endogenous ligand. The enzyme kinetic study demonstrated that 25HC3S specifically inhibited DNA methyltransferases (DNMTs), DNMT1, DNMT3a, and DNMT3b with IC50 of 4.04, 3.03, and 9.05 × 10-6 M, respectively. In human hepatocytes, high glucose induces lipid accumulation by increasing promoter CpG methylation of key genes involved in development of nonalcoholic fatty liver diseases. Using this model, whole genome bisulfate sequencing analysis demonstrated that 25HC3S converts the 5mCpG to CpG in the promoter regions of 1,074 genes. In addition, we observed increased expression of the demethylated genes, which are involved in the master signaling pathways, including MAPK-ERK, calcium-AMP-activated protein kinase, and type II diabetes mellitus pathways. mRNA array analysis showed that the upregulated genes encoded for key elements of cell survival; conversely, downregulated genes encoded for key enzymes that decrease lipid biosynthesis. Taken together, our results indicate that the expression of these key elements and enzymes are regulated by the demethylated signaling pathways. We summarized that 25HC3S DNA demethylation of 5mCpG in promoter regions is a potent regulatory mechanism.

Cholesterol Metabolites 25-Hydroxycholesterol and 25-Hydroxycholesterol 3-Sulfate Are Potent Paired Regulators: From Discovery to Clinical Usage

Oxysterols have long been believed to be ligands of nuclear receptors such as liver × receptor (LXR), and they play an important role in lipid homeostasis and in the immune system, where they are involved in both transcriptional and posttranscriptional mechanisms. However, they are increasingly associated with a wide variety of other, sometimes surprising, cell functions. Oxysterols have also been implicated in several diseases such as metabolic syndrome. Oxysterols can be sulfated, and the sulfated oxysterols act in different directions: they decrease lipid biosynthesis, suppress inflammatory responses, and promote cell survival. Our recent reports have shown that oxysterol and oxysterol sulfates are paired epigenetic regulators, agonists, and antagonists of DNA methyltransferases, indicating that their function of global regulation is through epigenetic modification. In this review, we explore our latest research of 25-hydroxycholesterol and 25-hydroxycholesterol 3-sulfate in a novel regulatory mechanism and evaluate the current evidence for these roles.

Constitutive Androstane Receptor: A Peripheral and a Neurovascular Stress or Environmental Sensor

Xenobiotic nuclear receptors (NR) are intracellular players involved in an increasing number of physiological processes. Examined and characterized in peripheral organs where they govern metabolic, transport and detoxification mechanisms, accumulating data suggest a functional expression of specific NR at the neurovascular unit (NVU). Here, we focus on the Constitutive Androstane Receptor (CAR), expressed in detoxifying organs such as the liver, intestines and kidneys. By direct and indirect activation, CAR is implicated in hepatic detoxification of xenobiotics, environmental contaminants, and endogenous molecules (bilirubin, bile acids). Importantly, CAR participates in physiological stress adaptation responses, hormonal and energy homeostasis due to glucose and lipid sensing. We next analyze the emerging evidence supporting a role of CAR in NVU cells including the blood-brain barrier (BBB), a key vascular interface regulating communications between the brain and the periphery. We address the emerging concept of how CAR may regulate specific P450 cytochromes at the NVU and the associated relevance to brain diseases. A clear understanding of how CAR engages during pathological conditions could enable new mechanistic, and perhaps pharmacological, entry-points within a peripheral-brain axis.

Sea cucumbers-derived sterol sulfate alleviates insulin resistance and inflammation in high-fat-high-fructose diet-induced obese mice

Sea cucumbers are widely consumed in traditional medicine and food. Sea cucumbers-derived sulfated sterol exhibits a sulfate group at C-3 position, which is different from phytosterol with a hydroxyl group. However, the effect of sterol sulfate on metabolic syndrome remains unknown. The purpose of the present study is to investigate the alleviation of sterol sulfate on high-fat-high-fructose diet (HFFD)-induced insulin resistance and inflammation. After 2 weeks feeding with HFFD, male C57BL/6J mice were continuously fed with HFFD plus 0.4 % (w/w) sterol sulfate or phytosterol for 6 weeks. The OGTT was carried out at 7 weeks. At the end of the experimental period, the changes of glycogen, circulating glucose, insulin, pro-inflammatory cytokine and adiponectin were measured. H&E staining was used to observe the morphological changes in adipose tissue. Furthermore, the underlying molecular mechanisms were investigated. Dietary sterol sulfate was superior to phytosterol in reducing body weight gain, adipocyte hypertrophy, and levels of circulating glucose and insulin, as well as increasing the glycogen content of tissues. Furthermore, sterol sulfate ameliorated insulin resistance mainly due to the inhibition of gluconeogenesis, the promotion of glycogen synthesis and GLUT4 translocation by activating PI3K/Akt signaling pathway. Additionally, sterol sulfate effectively attenuated inflammation by increasing serum adiponectin and reducing pro-inflammatory cytokine release. Sterol sulfate exhibited a more significant effect than phytosterol in alleviating HFFD -induced insulin resistance and inflammation, which might be closely related to the sulfate group. The results might provide insights into the prevention and alleviation of metabolic syndrome.

Cholesterol and oxysterol sulfates: Pathophysiological roles and analytical challenges

Cholesterol and oxysterol sulfates are important regulators of lipid metabolism, inflammation, cell apoptosis, and cell survival. Among the sulfate-based lipids, cholesterol sulfate (CS) is the most studied lipid both quantitatively and functionally. Despite the importance, very few studies have analysed and linked the actions of oxysterol sulfates to their physiological and pathophysiological roles. Overexpression of sulfotransferases confirmed the formation of a range of oxysterol sulfates and their antagonistic effects on liver X receptors (LXRs) prompting further investigations how are the changes to oxysterol/oxysterol sulfate homeostasis can contribute to LXR activity in the physiological milieu. Here, we aim to bring together for novel roles of oxysterol sulfates, the available techniques and the challenges associated with their analysis. Understanding the oxysterol/oxysterol sulfate levels and their pathophysiological mechanisms could lead to new therapeutic targets for metabolic diseases. LINKED ARTICLES: This article is part of a themed issue on Oxysterols, Lifelong Health and Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.16/issuetoc.

The Role of Sulfotransferases in Liver Diseases

The cytosolic sulfotransferases (SULTs) are phase II conjugating enzymes that catalyze the transfer of a sulfonate group from the universal sulfate donor 3'-phosphoadenosine-5'-phosphosulfate to a nucleophilic group of their substrates to generate hydrophilic products. Sulfation has a major effect on the chemical and functional homeostasis of substrate chemicals. SULTs are widely expressed in metabolically active or hormonally responsive tissues, including the liver and many extrahepatic tissues. The expression of SULTs exhibits isoform-, tissue-, sex-, and development-specific regulations. SULTs display a broad range of substrates including xenobiotics and endobiotics. The expression of SULTs has been shown to be transcriptionally regulated by members of the nuclear receptor superfamily, such as the peroxisome proliferator-activated receptors, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, liver X receptors, farnesoid X receptor, retinoid-related orphan receptors, estrogen-related receptors, and hepatocyte nuclear factor 4α These nuclear receptors can be activated by numerous xenobiotics and endobiotics, such as fatty acids, bile acids, and oxysterols, many of which are substrates of SULTs. Due to their metabolism of xenobiotics and endobiotics, SULTs and their regulations are implicated in the pathogenesis of many diseases. This review is aimed to summarize the central role of major SULTs, including the SULT1 and SULT2 subfamilies, in the pathophysiology of liver and liver-related diseases. SIGNIFICANCE STATEMENT: Sulfotransferases (SULTs) are indispensable in the homeostasis of xenobiotics and endobiotics. Knowing SULTs and their regulations are implicated in human diseases, it is hoped that genetic or pharmacological manipulations of the expression and/or activity of SULTs can be used to affect the clinical outcome of diseases.

Inhibition of LXR signaling by SULT2B1b promotes liver regeneration after partial hepatectomy in mouse models of nonalcoholic fatty liver disease

Hydroxysteroid sulfotransferase 2B1b (SULT2B1b) plays a critical role in hepatic energy homeostasis. Liver X receptors (LXRs) are implicated in multiple physiological functions, including the inhibition of hepatocyte proliferation and regulation of fatty acid and cholesterol metabolism. We have previously reported that SULT2B1b promotes hepatocyte proliferation by inactivating LXR signaling in vivo and in vitro, leading to our hypothesis that SULT2B1b promotes fatty liver regeneration. In the present study, female C57BL/6 and S129 mice were fed a high-fat diet for 8 wk to establish a nonalcoholic fatty liver disease (NAFLD) mouse model. 70% partial hepatectomy (PH) was performed to induce liver regeneration. Our experiments revealed that the SULT2B1b overexpression significantly promotes the regeneration of hepatocytes in NAFLD C57BL/6 mice after PH, increasing liver regrowth by 11% within 1 day, and then by 21%, 33%, and 24% by 2, 3, and 5 days post-PH, respectively. Compared with the wild-type NAFLD S129 mice, SULT2B1 deletion NAFLD S129 mice presented reduced hepatocyte regeneration at postoperative day 2, as verified by decreased liver regrowth (37.4% vs. 46.1%, P < 0.05) and the results of immunohistochemical staining, quantitative real-time polymerase chain reaction, and Western blot analysis. Moreover, LXRα signaling and SULT2B1b expression are highly correlated in the regeneration of NAFLD mouse liver; SULT2B1b overexpression suppresses LXRα signaling, while the LXRα-signaling agonist T0901317 blocks SULT2B1b-induced hepatocyte regeneration in NAFLD mouse liver. Thus, the upregulation of SULT2B1b may promote hepatocyte regeneration via the suppression of LXRα activation in NAFLD mice, providing a potential strategy for improving hepatic-steatosis-related liver regeneration disorders.NEW & NOTEWORTHY This study demonstrates for the first time that hydroxysteroid sulfotransferase 2B1b (SULT2B1b) overexpression promotes the regeneration of fatty liver after partial hepatectomy in mice with nonalcoholic fatty liver disease, while reducing triglyceride accumulation in the regenerative fatty liver. Liver X receptor signaling may be crucial in the SULT2B1b-mediated regeneration of fatty liver. Thus, SULT2B1b may be a potential target for treating hepatic steatosis-related liver regeneration disorders.

Cholesterol sulfate alters astrocyte metabolism and provides protection against oxidative stress

Cholesterol sulfate (CS) is one of the most important known sterol sulfates in human plasma and it is present as a normal constituent in a variety of human tissues. In both the brain and periphery, CS serves as a substrate for the synthesis of sulfonated adrenal steroids such as pregnenolone sulfate and dehydroepiandrosterone (DHEA) sulfate and as a constituent of many biological membranes including red blood cells where it functions as a stabilizing agent. It also acts as an endogenous regulator of cholesterol synthesis. However, the role of CS in brain metabolism and neurological disorder is unclear. In the current study we investigated the neuroprotective action of CS as well as its role in brain energy metabolism. The neuroprotective effect of CS and its role on cell metabolism were determined in primary astrocyte prepared from the cortex of postnatal day 0-2 C57BL/6 pups and a hippocampal HT-22 cell line using Calcein AM and MTT cell viability assay, flow cytometry, Seahorse extracellular flux analysis, and metabolism assay kits. We found that CS attenuates glutamate and rotenone induced cell death in HT-22 cells, decrease glutamate induced mitochondria membrane potential collapse, and reactive oxygen species production. Additionally, CS activates the Akt/Bcl₂ pathway. We observed that CS impacts astrocyte metabolism by increasing mitochondrial phosphorylation, ATP, and glycogen contents. Our study demonstrated that CS modulates brain energy metabolism and its neuroprotective effects might be due to the activation of Akt signaling or its ability to decrease reactive oxygen species production.

An Unexpected Role of Cholesterol Sulfotransferase and its Regulation in Sensitizing Mice to Acetaminophen-Induced Liver Injury

Overdose of acetaminophen (APAP) is the leading cause of acute liver failure (ALF) in the United States. The sulfotransferase-mediated sulfation of APAP is widely believed to be a protective mechanism to attenuate the hepatotoxicity of APAP. The cholesterol sulfotransferase SULT2B1b is best known for its activity in catalyzing the sulfoconjugation of cholesterol to synthesize cholesterol sulfate. SULT2B1b can be transcriptionally and positively regulated by the hepatic nuclear factor 4α (HNF4α). In this study, we uncovered an unexpected role for SULT2B1b in APAP toxicity. Hepatic overexpression of SULT2B1b sensitized mice to APAP-induced liver injury, whereas ablation of the Sult2B1b gene in mice conferred resistance to the APAP hepatotoxicity. Consistent with the notion that Sult2B1b is a transcriptional target of HNF4α, overexpression of HNF4α sensitized mice or primary hepatocytes to APAP-induced hepatotoxicity in a Sult2B1b-dependent manner. We conclude that the HNF4α-SULT2B1b axis has a unique role in APAP-induced acute liver injury, and SULT2B1b induction might be a risk factor for APAP hepatotoxicity.

The Role of Xenobiotic Receptors on Hepatic Glycolipid Metabolism

Background:

PXR (Pregnane X Receptor) and CAR (Constitutive Androstane Receptor) are termed as xenobiotic receptors, which are known as core factors in regulation of the transcription of metabolic enzymes and drug transporters. However, accumulating evidence has shown that PXR and CAR exert their effects on energy metabolism through the regulation of gluconeogenesis, lipogenesis and β-oxidation. Therefore, in this review, we are trying to summary recent advances to show how xenobiotic receptors regulate energy metabolism.

Methods:

A structured search of databases has been performed by using focused review topics. According to conceptual framework, the main idea of research literature was summarized and presented.

Results:

For introduction of each receptor, the general introduction and the critical functions in hepatic glucose and lipid metabolism have been included. Recent important studies have shown that CAR acts as a negative regulator of lipogenesis, gluconeogenesis and β -oxidation. PXR activation induces lipogenesis, inhibits gluconeogenesis and inhabits β-oxidation.

Conclusion:

In this review, the importance of xenobiotic receptors in hepatic glucose and lipid metabolism has been confirmed. Therefore, PXR and CAR may become new therapeutic targets for metabolic syndrome, including obesity and diabetes. However, further research is required to promote the clinical application of this new energy metabolism function of xenobiotic receptors.

A sulfotransferase dosage-dependently regulates mouthpart polyphenism in the nematode Pristionchus pacificus

Polyphenism, the extreme form of developmental plasticity, is the ability of a genotype to produce discrete morphologies matched to alternative environments. Because polyphenism is likely to be under switch-like molecular control, a comparative genetic approach could reveal the molecular targets of plasticity evolution. Here we report that the lineage-specific sulfotransferase SEUD-1, which responds to environmental cues, dosage-dependently regulates polyphenism of mouthparts in the nematode Pristionchus pacificus. SEUD-1 is expressed in cells producing dimorphic morphologies, thereby integrating an intercellular signalling mechanism at its ultimate target. Additionally, multiple alterations of seud-1 support it as a potential target for plasticity evolution. First, a recent duplication of seud-1 in a sister species reveals a direct correlation between genomic dosage and polyphenism threshold. Second, inbreeding to produce divergent polyphenism thresholds resulted in changes in transcriptional dosage of seud-1. Our study thus offers a genetic explanation for how plastic responses evolve.

Higher steroid sulfation is linked to successful weight loss in obese children

Objective Little information is available on the steroid sulfates profile in obese children. Therefore, we examined whether sulfated steroids are linked with weight status and associated comorbidities in obese children. Methods We analyzed 66 obese children (mean age 10.5 ± 2.5 years, 57.6% female, 53.9% prepubertal, mean BMI 27.0 ± 4.6 kg/m2, 50% with BMI-SDS reduction >0.5, 50% without BMI-SDS reduction) who participated in an outpatient 1-year intervention program based on exercise, behavior and nutrition therapy. We measured intact sulfated steroids (cholesterol sulfate (CS), pregnenolone sulfate (PregS), 17αOH pregnenolone sulfate (17OH-PregS), 16αOH dehydroepiandrosterone sulfate (16OH-DHEAS), DHEAS, androstenediol-3-sulfate, androsterone sulfate and epiandrosterone sulfate) by LC-MS/MS, and insulin resistance index HOMA, lipids, blood pressure at baseline and 1 year later. Results All sulfated steroids except 17OH-PregS, 16OH-DHEAS, androsterone sulfate and epiandrosterone sulfate were higher in boys compared to girls. Concentrations of CS before intervention were higher in children who lost weight. After 1 year of treatment, both groups showed increased levels of DHEAS, 16OH-DHEAS and androstenediol-3-sulfate, but PregS was only increased in children with weight loss. None of the steroid sulfates was significantly related to cardiovascular risk factors or HOMA except 17OH-PregS, which was associated with systolic blood pressure both in cross-sectional (β-coefficient: 0.09 ± 0.07, P = 0.020) and longitudinal analyses (β-coefficient: 0.06 ± 0.04, P = 0.013) in multiple linear regression analyses. Conclusions Since higher steroid sulfation capacity was associated with successful weight intervention in children disruption of sulfation may be associated with difficulties to lose weight. Future studies are necessary to prove this hypothesis.

Regulation of Cholesterol Sulfotransferase SULT2B1b by Hepatocyte Nuclear Factor 4α Constitutes a Negative Feedback Control of Hepatic Gluconeogenesis

The cholesterol sulfotransferase SULT2B1b converts cholesterol to cholesterol sulfate (CS). We previously reported that SULT2B1b inhibits hepatic gluconeogenesis by antagonizing the gluconeogenic activity of hepatocyte nuclear factor 4α (HNF4α). In this study, we showed that the SULT2B1b gene is a transcriptional target of HNF4α, which led to our hypothesis that the induction of SULT2B1b by HNF4α represents a negative feedback to limit the gluconeogenic activity of HNF4α. Indeed, downregulation of Sult2B1b enhanced the gluconeogenic activity of HNF4α, which may have been accounted for by the increased acetylation of HNF4α as a result of decreased expression of the HNF4α deacetylase sirtuin 1 (Sirt1). The expression of Sult2B1b was also induced by HNF4α upon fasting, and the Sult2B1b null (Sult2B1b-/-) mice showed increased gluconeogenic gene expression and an elevated fasting glucose level, suggesting that SULT2B1b also plays a restrictive role in HNF4α-mediated fasting-responsive gluconeogenesis. We also developed thiocholesterol, a hydrolysis-resistant derivative of CS, which showed superior activity to that of the native CS in inhibiting gluconeogenesis and improving insulin sensitivity in high-fat-diet-induced diabetic mice. We conclude that the HNF4α-SULT2B1b-CS axis represents a key endogenous mechanism to prevent uncontrolled gluconeogenesis. Thiocholesterol may be used as a therapeutic agent to manage hyperglycemia.

RORα Induces KLF4-Mediated M2 Polarization in the Liver Macrophages that Protect against Nonalcoholic Steatohepatitis

The regulation of M1/M2 polarization in liver macrophages is closely associated with the progression of nonalcoholic steatohepatitis (NASH); however, the mechanism involved in this process remains unclear. Here, we describe the orphan nuclear receptor retinoic-acid-related orphan receptor α (RORα) as a key regulator of M1/M2 polarization in hepatic residential Kupffer cells (KCs) and infiltrated monocyte-derived macrophages. RORα enhanced M2 polarization in KCs by inducing the kruppel-like factor 4. M2 polarization was defective in KCs and bone-marrow-derived macrophages of the myeloid-specific RORα null mice, and these mice were susceptible to HFD-induced NASH. We found that IL-10 played an important role in connecting the function of M2 KCs to lipid accumulation and apoptosis in hepatocytes. Importantly, M2 polarization was controlled by a RORα activator, JC1-40, which improved symptoms of NASH. Our results suggest that the M2-promoting effects of RORα in liver macrophages may provide better therapeutic strategies against NASH.

Cholesterol metabolites alleviate injured liver function and decrease mortality in an LPS-induced mouse model

BACKGROUND

Oxysterol sulfation plays a fundamental role in the regulation of many biological events. Its products, 25-hydroxycholesterol 3-sulfate (25HC3S) and 25-hydroxycholesterol 3, 25-disulfate (25HCDS), have been demonstrated to be potent regulators of lipid metabolism, inflammatory response, cell apoptosis, and cell survival. In the present study, we tested these products' potential to treat LPS-induced acute liver failure in a mouse model.

METHODS

Acute liver failure mouse model was established by intravenous injection with LPS. The injured liver function was treated with intraperitoneal administration of 25HC, 25HC3S or 25HCDS. Serum enzymatic activities were determined in our clinic laboratory. ELISA assays were used to detect pro-inflammatory factor levels in sera. Western blot, Real-time Quantitative PCR and RT² Profiler PCR Array analysis were used to determine levels of gene expression.

RESULTS

Administration of 25HC3S/25HCDS decreased serum liver-impaired markers; suppressed secretion of pro-inflammatory factors; alleviated liver, lung, and kidney injury; and subsequently increased the survival rate in the LPS-induced mouse model. These effects resulted from the inhibition of the expression of genes involved in the pro-inflammatory response and apoptosis and the simultaneous induction of the expression of genes involved in cell survival. Compared to 25HC, 25HC3S and 25HCDS exhibited significantly stronger effects in these activities, indicating that the cholesterol metabolites play an important role in the inflammatory response, cell apoptosis, and cell survival in vivo.

CONCLUSIONS

25HC3S/25HCDS has potential to serve as novel biomedicines in the therapy of acute liver failure and acute multiple organ failure.

Genetic and Clinical Predictive Factors of Sulfonylurea Failure in Patients with Type 2 Diabetes

BACKGROUND

Sulfonylureas are widely used to treat type 2 diabetes (T2DM). Although genetic variations are associated with sulfonylurea treatment responses in T2DM patients, whether these variations can be used to predict heterogeneous treatment responses is unclear. In this study, we assessed the potential utility of combining information from multiple variants and phenotypes to predict sulfonylurea response.

METHODS

Using data from the "Glibenclamide" arm (365 patients) of the Xiaoke Pill Trial that evaluated the safety and efficacy of sulfonylurea, we identified genetic variants associated with sulfonylurea treatment response, and we explored their ability to predict drug response when combined with phenotype information.

RESULTS

The association of 780 single-nucleotide polymorphisms (using Infinium HD iSelect chip) with drug efficacy was evaluated, and four genes identified with drug metabolism (FMO2, FMO3, UGT2B15, and CYP51A1, P < 0.05) were found to be associated with changes in HbA1c. In a clinical model, the baseline values of HbA1c and disposition index (DI) were significantly associated with HbA1c and fasting plasma glucose (FPG) target achievements. Compared with clinical models, the inclusion of genetic markers significantly increased the predictive ability for both HbA1c- and FPG-based outcomes.

CONCLUSIONS

Our findings suggest that altered protein function in multiple pathways may cooperatively contribute to the increased discrimination by area under receiver operating curve for T2DM patients, and it may explain, in part, the relationship between inter-individual variability and the sulfonylurea response.

The Nuclear Hormone Receptor NHR-40 Acts Downstream of the Sulfatase EUD-1 as Part of a Developmental Plasticity Switch in Pristionchus

Developmental plasticity, the ability of one genotype to produce distinct phenotypes in different environments, has been suggested to facilitate phenotypic diversification, and several examples in plants and animals support its macroevolutionary potential [1-8]. However, little is known about associated molecular mechanisms, because environmental effects on development are difficult to study by laboratory approaches. One promising system is the mouth dimorphism of the nematode Pristionchus pacificus [9-12]. Following an irreversible decision in larval development, these nematodes form moveable teeth that occur in either of two discrete morphs. The "eurystomatous" (Eu) form has a wide mouth and two teeth, allowing predatory feeding on other nematodes. In contrast, the alternative ("stenostomatous"; St) form has diminutive mouthparts that largely constrain its diet to microbes. The sulfatase EUD-1 was previously discovered to execute a polyphenism switch based on dosage of functional alleles [13] and confirmed a prediction of evolutionary theory about how developmental switches control plasticity [1, 3]. However, the genetic context of this single gene, and hence the molecular complexity of switch mechanisms, was previously unknown. Here we use a suppressor screen to identify factors downstream of eud-1 in mouth-form regulation. We isolated three dominant, X-linked mutants in the nuclear hormone receptor gene nhr-40 that are haploinsufficient. Both eud-1 nhr-40 double and nhr-40 single mutants are all Eu, whereas transgenic overexpression of nhr-40 does not restore the wild-type phenotype but instead results in nearly all-St lines. Thus, NHR-40 is part of a developmental switch, suggesting that switch mechanisms controlling plasticity consist of multi-component hormonal signaling systems.

A MALDI-MSI Approach to the Characterization of Radiation-Induced Lung Injury and Medical Countermeasure Development

Radiation-induced lung injury is highly complex and characterized by multiple pathologies, which occur over time and sporadically throughout the lung. This complexity makes biomarker investigations and medical countermeasure screenings challenging. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has the ability to resolve differences spatially in molecular profiles within the lung following radiation exposure and can aid in biomarker identification and pharmaceutical efficacy investigations. MALDI-MSI was applied to the investigation of a whole-thorax lung irradiation model in non-human primates (NHP) for lipidomic analysis and medical countermeasure distribution.

Deciphering the roles of the constitutive androstane receptor in energy metabolism

The constitutive androstane receptor (CAR) is initially defined as a xenobiotic nuclear receptor that protects the liver from injury. Detoxification of damaging chemicals is achieved by CAR-mediated induction of drug-metabolizing enzymes and transporters. More recent research has implicated CAR in energy metabolism, suggesting a therapeutic potential for CAR in metabolic diseases, such as type 2 diabetes and obesity. A better understanding of the mechanisms by which CAR regulates energy metabolism will allow us to take advantage of its effectiveness while avoiding its side effects. This review summarizes the current progress on the regulation of CAR nuclear translocation, upstream modulators of CAR activity, and the crosstalk between CAR and other transcriptional factors, with the aim of elucidating how CAR regulates glucose and lipid metabolism.

Exposure to common food additive carrageenan alone leads to fasting hyperglycemia and in combination with high fat diet exacerbates glucose intolerance and hyperlipidemia without effect on weight

AIMS

Major aims were to determine whether exposure to the commonly used food additive carrageenan could induce fasting hyperglycemia and could increase the effects of a high fat diet on glucose intolerance and dyslipidemia.

METHODS

C57BL/6J mice were exposed to either carrageenan, high fat diet, or the combination of high fat diet and carrageenan, or untreated, for one year. Effects on fasting blood glucose, glucose tolerance, lipid parameters, weight, glycogen stores, and inflammation were compared.

RESULTS

Exposure to carrageenan led to glucose intolerance by six days and produced elevated fasting blood glucose by 23 weeks. Effects of carrageenan on glucose tolerance were more severe than from high fat alone. Carrageenan in combination with high fat produced earlier onset of fasting hyperglycemia and higher glucose levels in glucose tolerance tests and exacerbated dyslipidemia. In contrast to high fat, carrageenan did not lead to weight gain. In hyperinsulinemic, euglycemic clamp studies, the carrageenan-exposed mice had higher early glucose levels and lower glucose infusion rate and longer interval to achieve the steady-state.

CONCLUSIONS

Carrageenan in the Western diet may contribute to the development of diabetes and the effects of high fat consumption. Carrageenan may be useful as a nonobese model of diabetes in the mouse.

Identification of novel regulatory cholesterol metabolite, 5-cholesten, 3β,25-diol, disulfate

Oxysterol sulfation plays an important role in regulation of lipid metabolism and inflammatory responses. In the present study, we report the discovery of a novel regulatory sulfated oxysterol in nuclei of primary rat hepatocytes after overexpression of the gene encoding mitochondrial cholesterol delivery protein (StarD1). Forty-eight hours after infection of the hepatocytes with recombinant StarD1 adenovirus, a water-soluble oxysterol product was isolated and purified by chemical extraction and reverse-phase HPLC. Tandem mass spectrometry analysis identified the oxysterol as 5-cholesten-3β, 25-diol, disulfate (25HCDS), and confirmed the structure by comparing with a chemically synthesized compound. Administration of 25HCDS to human THP-1-derived macrophages or HepG2 cells significantly inhibited cholesterol synthesis and markedly decreased lipid levels in vivo in NAFLD mouse models. RT-PCR showed that 25HCDS significantly decreased SREBP-1/2 activities by suppressing expression of their responding genes, including ACC, FAS, and HMG-CoA reductase. Analysis of lipid profiles in the liver tissues showed that administration of 25HCDS significantly decreased cholesterol, free fatty acids, and triglycerides by 30, 25, and 20%, respectively. The results suggest that 25HCDS inhibits lipid biosynthesis via blocking SREBP signaling. We conclude that 25HCDS is a potent regulator of lipid metabolism and propose its biosynthetic pathway.