Comparison of pharmaceutical properties and biological activities of prednisolone, deflazacort, and vamorolone in DMD disease models.

Duchenne muscular dystrophy (DMD) is a progressive disabling X-linked recessive disorder that causes gradual and irreversible loss of muscle, resulting in early death. The corticosteroids prednisone/prednisolone and deflazacort are used to treat DMD as the standard of care; however, only deflazacort is FDA approved for DMD. The novel atypical corticosteroid vamorolone is being investigated for treatment of DMD. We compared the pharmaceutical properties as well as the efficacy and safety of the three corticosteroids across multiple doses in the B10-mdx DMD mouse model. Pharmacokinetic studies in the mouse and evaluation of p-glycoprotein (P-gP) efflux in a cellular system demonstrated that vamorolone is not a strong P-gp substrate resulting in measurable central nervous system (CNS) exposure in the mouse. In contrast, deflazacort and prednisolone are strong P-gp substrates. All three corticosteroids showed efficacy, but also side effects at efficacious doses. After dosing mdx mice for two weeks, all three corticosteroids induced changes in gene expression in the liver and the muscle, but prednisolone and vamorolone induced more changes in the brain than did deflazacort. Both prednisolone and vamorolone induced depression-like behavior. All three corticosteroids reduced endogenous corticosterone levels, increased glucose levels, and reduced osteocalcin levels. Using micro-computed tomography, femur bone density was decreased, reaching significance with prednisolone. The results of these studies indicate that efficacious doses of vamorolone, are associated with similar side effects as seen with other corticosteroids. Further, because vamorolone is not a strong P-gp substrate, vamorolone distributes into the CNS increasing the potential CNS side-effects.

Critical weather limits for paddy rice under diverse ecosystems of India.

Rice yields are largely influenced by variability in weather. Here, we demonstrate the effect of weather variables viz., maximum and minimum temperatures, rainfall, morning and evening relative humidity, bright sunshine hours on the yield of rice cv. Swarna, grown across five rice ecologies of India through field experiments during kharif (wet) season (Jun-Sept.). Critical thresholds of weather elements were identified for achieving above average, average and below average yield for each ecology. The investigation could determine how different weather elements individually and collectively affect rice yield in different rice ecosystems of India. While a sudden increase in minimum temperature by 8-10 °C (> 30 °C) during reproductive period resulted in 40-50 per cent yield reduction at Mohanpur, a sudden decrease (< 20 °C) caused yield decline at Dapoli. The higher yields may be attributed to a significant difference in bright sunshine hours between reproductive phases of above-average and below-average yield years (ranging from 2.8 to 7.8 hours during P5 stages and 1.7 to 5.1 during P4 stages). Rice cultivar Swarna performed differently at various sowing dates in a location as well as across locations (6650 kg ha-1 at Dapoli to 1101 kg ha-1 at Samastipur). It was also found that across all locations, the above average yield could be associated with higher range of maximum temperature compared to that of below average yield. Principal component analysis explained 77 per cent of cumulative variance among the variables at first growth stage, whereas 70 per cent at second growth stage followed by 74 per cent and 66 per cent at subsequent growth stages. We found that coastal locations, in contrast to inland ones, could maximize the yield potential of the cultivar Swarna, due to the longer duration of days between panicle initiation to physiological maturity. We anticipate that the location-specific thresholds of weather factors will encourage rice production techniques that are climate resilient.

Recent Advances in Drug Discovery Toxicology.

Major advances in scientific discovery and insights that stem from the development and use of new techniques and models can bring remarkable progress to conventional toxicology. Although animal testing is still considered as the "gold standard" in traditional toxicity testing, there is a necessity for shift from animal testing to alternative methods regarding the drug safety testing owing to the emerging state-of-art techniques and the proposal of 3Rs (replace, reduce, and refine) towards animal welfare. This review describes some recent research methods in drug discovery toxicology, including in vitro cell and organ-on-a-chip, imaging systems, model organisms (C. elegans, Danio rerio, and Drosophila melanogaster), and toxicogenomics in modern toxicology testing.

Glucagon like receptor 1/ glucagon dual agonist acutely enhanced hepatic lipid clearance and suppressed de novo lipogenesis in mice.

Lipid lowering properties of glucagon have been reported. Blocking glucagon signaling leads to rise in plasma LDL levels. Here, we demonstrate the lipid lowering effects of acute dosing with Glp1r/Gcgr dual agonist (DualAG). All the experiments were performed in 25 week-old male diet-induced (60% kCal fat) obese mice. After 2 hrs of fasting, mice were injected subcutaneously with vehicle, liraglutide (25nmol/kg) and DualAG (25nmol/kg). De novo cholesterol and palmitate synthesis was measured by deuterium incorporation method using D2O. 13C18-oleate infusion was used for measuring fatty acid esterification. Simultaneous activation of Glp1r and Gcgr resulted in decrease in plasma triglyceride and cholesterol levels. DualAG enhanced hepatic LDLr protein levels, along with causing decrease in content of plasma ApoB48 and ApoB100. VLDL secretion, de novo palmitate synthesis and fatty acid esterification decreased with acute DualAG treatment. On the other hand, ketone levels were elevated with DualAG treatment, indicating increased fatty acid oxidation. Lipid relevant changes were absent in liraglutide treated group. In an acute treatment, DualAG demonstrated significant impact on lipid homeostasis, specifically on hepatic uptake, VLDL secretion and de novo synthesis. These effects collectively reveal that lipid lowering abilities of DualAG are primarily through glucagon signaling and are liver centric.

Hepatic Lipid Accumulation and Nrf2 Expression following Perinatal and Peripubertal Exposure to Bisphenol A in a Mouse Model of Nonalcoholic Liver Disease.

BACKGROUND: Exposure to chemicals during critical windows of development may re-program liver for increased risk of nonalcoholic fatty liver disease (NAFLD). Bisphenol A (BPA), a plastics component, has been described to impart adverse effects during gestational and lactational exposure. Our work has pointed to nuclear factor E2-related factor 2 (Nrf2) being a modulator of hepatic lipid accumulation in models of NAFLD. OBJECTIVES: To determine if chemical exposure can prime liver for steatosis via modulation of NRF2 and epigenetic mechanisms. METHODS: Utilizing BPA as a model exposure, pregnant CD-1 mice were administered 25µg/kg/day BPA via osmotic minipumps from gestational day 8 through postnatal day (PND)16. The offspring were weaned on PND21 and exposed to same dose of BPA via their drinking water through PND35. Tissues were collected from pups at week 5 (W5), and their littermates at week 39 (W39). RESULTS: BPA increased hepatic lipid content concomitant with increased Nrf2 and pro-lipogenic enzyme expression at W5 and W39 in female offspring. BPA exposure increased Nrf2 binding to a putative antioxidant response element consensus sequence in the sterol regulatory-element binding protein-1c (Srebp-1c) promoter. Known Nrf2 activators increased SREBP-1C promoter reporter activity in HepG2 cells. Methylated DNA immunoprecipitation-PCR and pyrosequencing revealed that developmental BPA exposure induced hypomethylation of the Nrf2 and Srebp-1c promoters in livers of W5 mice, which was more prominent in W39 mice than in others. CONCLUSION: Exposure to a xenobiotic during early development induced persistent fat accumulation via hypomethylation of lipogenic genes. Moreover, increased Nrf2 recruitment to the Srebp-1c promoter in livers of BPA-exposed mice was observed. Overall, the underlying mechanisms described a broader impact beyond BPA exposure and can be applied to understand other models of NAFLD. https://doi.org/10.1289/EHP664.

PPAR-α, a lipid-sensing transcription factor, regulates blood-brain barrier efflux transporter expression.

Lipid sensor peroxisome proliferator-activated receptor alpha (PPAR- α) is the master regulator of lipid metabolism. Dietary release of endogenous free fatty acids, fibrates, and certain persistent environmental pollutants, e.g. perfluoroalkyl fire-fighting foam components, are peroxisome proliferator-activated receptor alpha ligands. Here, we define a role for peroxisome proliferator-activated receptor alpha in regulating the expression of three ATP-driven drug efflux transporters at the rat and mouse blood-brain barriers: P-glycoprotein (Abcb1), breast cancer resistance protein (Bcrp/Abcg2), and multidrug resistance-associated protein 2 (Mrp2/Abcc2). Exposing isolated rat brain capillaries to linoleic acid, clofibrate, or PKAs increased the transport activity and protein expression of the three ABC transporters. These effects were blocked by the PPAR- α antagonist, GW6471. Dosing rats with 20 mg/kg or 200 mg/kg of clofibrate decreased the brain accumulation of the P-glycoprotein substrate, verapamil, by 50% (in situ brain perfusion; effects blocked by GW6471) and increased P-glycoprotein expression and activity in capillaries ex vivo. Fasting C57Bl/6 wild-type mice for 24 h increased both serum lipids and brain capillary P-glycoprotein transport activity. Fasting did not alter P-glycoprotein activity in PPAR- α knockout mice. These results indicate that hyperlipidemia, lipid-lowering fibrates and exposure to certain fire-fighting foam components activate blood-brain barrier peroxisome proliferator-activated receptor alpha, increase drug efflux transporter expression and reduce drug delivery to the brain.

Serum Natriuretic Peptides as Differential Biomarkers Allowing for the Distinction between Physiologic and Pathologic Left Ventricular Hypertrophy.

Given the proven utility of natriuretic peptides as serum biomarkers of cardiovascular maladaptation and dysfunction in humans and the high cross-species sequence conservation of atrial natriuretic peptides, natriuretic peptides have the potential to serve as translational biomarkers for the identification of cardiotoxic compounds during multiple phases of drug development. This work evaluated and compared the response of N-terminal proatrial natriuretic peptide (NT-proANP) and N-terminal probrain natriuretic peptide (NT-proBNP) in rats during exercise-induced and drug-induced increases in cardiac mass after chronic swimming or daily oral dosing with a peroxisome proliferator-activated receptor γ agonist. Male Sprague-Dawley rats aged 8 to 10 weeks were assigned to control, active control, swimming, or drug-induced cardiac hypertrophy groups. While the relative heart weights from both the swimming and drug-induced cardiac hypertrophy groups were increased 15% after 28 days of dosing, the serum NT-proANP and NT-proBNP values were only increased in association with cardiac hypertrophy caused by compound administration. Serum natriuretic peptide concentrations did not change in response to adaptive physiologic cardiac hypertrophy induced by a 28-day swimming protocol. These data support the use of natriuretic peptides as fluid biomarkers for the distinction between physiological and drug-induced cardiac hypertrophy.

In vivo and ex vivo regulation of breast cancer resistant protein (Bcrp) by peroxisome proliferator-activated receptor alpha (Pparα) at the blood-brain barrier.

Breast cancer resistance protein (Bcrp/Abcg2) localized at the blood-brain barrier (BBB) limits permeability into the brain of many xenobiotics, including pharmacological agents. Peroxisome proliferator-activated receptor α (Pparα), a ligand-activated transcription factor, primarily involved in lipid metabolism, has been shown to regulate the functional expression of Bcrp in human cerebral microvascular endothelial cells (hCMEC/D3). The aim of this study was to investigate ex vivo and in vivo, the regulation of Bcrp by Pparα in an intact BBB. Ex vivo quantitative real-time PCR and immunoblot analyses showed significant up-regulation of Abcg2/Bcrp mRNA and protein levels in CD-1 mouse brain capillaries incubated with clofibrate, a Pparα ligand. Fluorescence-based transport assays in CD-1 and C57BL/6 brain capillaries showed that exposure to clofibrate significantly increased Bcrp transport activity. This increase was not observed in capillaries isolated from Pparα knockout mice. In vivo, we found: i) significant Bcrp protein up-regulation in clofibrate-dosed CD-1 and C57BL/6 capillary lysates, but no effect in Pparα knockout capillary lysates, and ii) significantly increased Bcrp transport activity in capillaries isolated from clofibrate-treated mice. These results demonstrate an increase in Bcrp functional expression by Pparα in brain capillaries, and suggest that Pparα is another nuclear receptor that can contribute to the regulation of membrane efflux transporters and drug permeability at the BBB. We propose the involvement of the following pathways in clofibrate-mediated induction of the drug transporter Abcg2/Bcrp mRNA, protein expression and function by the nuclear receptor Pparα, in mouse brain capillary endothelial cells. Upon activation with clofibrate (Pparα, ligand), Pparα complex translocates from the cytoplasm into the nucleus and further recruits coactivators and transcription machinery which induce the transcription of Abcg2 gene and ultimately results in upregulation of Bcrp protein expression and function. These findings have significant implications since Bcrp is known to play an important role at the BBB in preventing the permeability of several xenobiotics and drugs into the brain.

Deficiency in Nrf2 transcription factor decreases adipose tissue mass and hepatic lipid accumulation in leptin-deficient mice.

OBJECTIVE: To evaluate whether Nrf2 deficiency impacts insulin resistance and lipid accumulation in liver and white adipose tissue. METHODS: Lep(ob/ob) mice (OB) with targeted Nrf2 deletion (OB-Nrf2KO) were generated. Pathogenesis of obesity and type 2 diabetes was measured in C57BL/6J, Nrf2KO, OB, and OB-Nrf2KO mice. Hepatic lipid content, lipid clearance, and very low-density lipoprotein (VLDL) secretion were determined between OB and OB-Nrf2KO mice. RESULTS: OB-Nrf2KO mice exhibited decreased white adipose tissue mass and decreased adipogenic and lipogenic gene expression compared with OB mice. Nrf2 deficiency prolonged hyperglycemia in response to glucose challenge, which was paralleled by reduced insulin-stimulated Akt phosphorylation. In OB mice, Nrf2 deficiency decreased hepatic lipid accumulation, decreased peroxisome proliferator-activated receptor γ expression and nicotinamide adenine dinucleotide phosphate (NADPH) content, and enhanced VLDL secretion. However, this observation was opposite in lean mice. Additionally, OB-Nrf2KO mice exhibited increased plasma triglyceride content, decreased HDL-cholesterol content, and enhanced apolipoprotein B expression, suggesting Nrf2 deficiency caused dyslipidemia in these mice. CONCLUSIONS: Nrf2 deficiency in Lep(ob/ob) mice reduced white adipose tissue mass and prevented hepatic lipid accumulation but induced insulin resistance and dyslipidemia. This study indicates a dual role of Nrf2 during metabolic dysregulation-increasing lipid accumulation in liver and white adipose tissue but preventing lipid accumulation in obese mice.

Downregulation of sulfotransferase expression and activity in diseased human livers.

Sulfotransferase (SULT) function has been well studied in healthy human subjects by quantifying mRNA and protein expression and determining enzyme activity with probe substrates. However, it is not well known if sulfotransferase activity changes in metabolic and liver disease, such as diabetes, steatosis, or cirrhosis. Sulfotransferases have significant roles in the regulation of hormones and excretion of xenobiotics. In the present study of normal subjects with nonfatty livers and patients with steatosis, diabetic cirrhosis, and alcoholic cirrhosis, we sought to determine SULT1A1, SULT2A1, SULT1E1, and SULT1A3 activity and mRNA and protein expression in human liver tissue. In general, sulfotransferase activity decreased significantly with severity of liver disease from steatosis to cirrhosis. Specifically, SULT1A1 and SULT1A3 activities were lower in disease states relative to nonfatty tissues. Alcoholic cirrhotic tissues further contained lower SULT1A1 and 1A3 activities than those affected by either of the two other disease states. SULT2A1, on the other hand, was only reduced in alcoholic cirrhotic tissues. SULT1E1 was reduced both in diabetic cirrhosis and in alcoholic cirrhosis tissues, relative to nonfatty liver tissues. In conclusion, the reduced levels of sulfotransferase expression and activity in diseased versus nondiseased liver tissue may alter the metabolism and disposition of xenobiotics and affect homeostasis of endobiotic sulfotransferase substrates.

Alcohol cirrhosis alters nuclear receptor and drug transporter expression in human liver.

Unsafe use of alcohol results in approximately 2.5 million deaths worldwide, with cirrhosis contributing to 16.6% of reported deaths. Serum insulin levels are often elevated in alcoholism and may result in diabetes, which is why alcoholic liver disease and diabetes often are present together. Because there is a sizable population with these diseases alone or in combination, the purpose of this study was to determine whether transporter expression in human liver is affected by alcoholic cirrhosis, diabetes, and alcoholic cirrhosis coexisting with diabetes. Transporters aid in hepatobiliary excretion of many drugs and toxic chemicals and can be determinants of drug-induced liver injury. Drug transporter expression and transcription factor-relative mRNA and protein expression in normal, diabetic, cirrhotic, and cirrhosis with diabetes human livers were quantified. Cirrhosis significantly increased ABCC4, 5, ABCG2, and solute carrier organic anion (SLCO) 2B1 mRNA expression and decreased SLCO1B3 mRNA expression in the liver. ABCC1, 3-5, and ABCG2 protein expression was also upregulated by alcoholic cirrhosis. ABCC3-5 and ABCG2 protein expression was also upregulated in diabetic cirrhosis. Cirrhosis increased nuclear factor E2-related factor 2 mRNA expression, whereas it decreased pregnane-X-receptor and farnesoid-X-receptor mRNA expression in comparison with normal livers. Hierarchical cluster analysis indicated that expressions of ABCC2, 3, and 6; SLCO1B1 and 1B3; and ABCC4 and 5 were more closely related in the livers from this cohort. Overall, alcoholic cirrhosis altered transporter expression in human liver.

Keap1 knockdown increases markers of metabolic syndrome after long-term high fat diet feeding.

The nuclear factor E2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway upregulates antioxidant and biotransformation enzyme expression to counter cellular oxidative stress. The contributions of Nrf2 to other cellular functions, such as lipid homeostasis, are emerging. This study was conducted to determine how enhanced Nrf2 activity influences the progression of metabolic syndrome with long-term high-fat diet (HFD) feeding. C57BL/6 and Keap1-knockdown (Keap1-KD) mice, which exhibit enhanced Nrf2 activity, were fed a HFD for 24 weeks. Keap1-KD mice had higher body weight and white adipose tissue mass compared to C57BL/6 mice on HFD, along with increased inflammation and lipogenic gene expression. HFD feeding increased hepatic steatosis and inflammation to a greater extent in Keap1-KD mice compared to C57BL/6 mice, which was associated with increased liver Cd36, fatty acid-binding protein 4, and monocyte chemoattractant protein 1 mRNA expression, as well as increased acetyl-CoA carboxylase 1 and stearoyl-CoA desaturase-1 protein expression. The HFD altered short-term glucose homeostasis to a greater degree in Keap-KD mice compared to C57BL/6 mice, which was accompanied by downregulation of insulin receptor substrate 1 mRNA expression in skeletal muscle. Together, the results indicate that Keap1 knockdown, on treatment with HFD, increases certain markers of metabolic syndrome.

Altered UDP-glucuronosyltransferase and sulfotransferase expression and function during progressive stages of human nonalcoholic fatty liver disease.

The UDP-glucuronosyltransferases (UGTs) and sulfotransferases (SULTs) represent major phase II drug-metabolizing enzymes that are also responsible for maintaining cellular homeostasis by metabolism of several endogenous molecules. Perturbations in the expression or function of these enzymes can lead to metabolic disorders and improper management of xenobiotics and endobiotics. Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of liver damage ranging from steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Because the liver plays a central role in the metabolism of xenobiotics, the purpose of the current study was to determine the effect of human NAFLD progression on the expression and function of UGTs and SULTs in normal, steatosis, NASH (fatty), and NASH (not fatty/cirrhosis) samples. We identified upregulation of UGT1A9, 2B10, and 3A1 and SULT1C4 mRNA in both stages of NASH, whereas UGT2A3, 2B15, and 2B28 and SULT1A1, 2B1, and 4A1 as well as 3'-phosphoadenosine-5'-phosphosulfate synthase 1 were increased in NASH (not fatty/cirrhosis) only. UGT1A9 and 1A6 and SULT1A1 and 2A1 protein levels were decreased in NASH; however, SULT1C4 was increased. Measurement of the glucuronidation and sulfonation of acetaminophen (APAP) revealed no alterations in glucuronidation; however, SULT activity was increased in steatosis compared with normal samples, but then decreased in NASH compared with steatosis. In conclusion, the expression of specific UGT and SULT isoforms appears to be differentially regulated, whereas sulfonation of APAP is disrupted during progression of NAFLD.

Bile salt export pump is dysregulated with altered farnesoid X receptor isoform expression in patients with hepatocellular carcinoma.

UNLABELLED: As a canalicular bile acid effluxer, the bile salt export pump (BSEP) plays a vital role in maintaining bile acid homeostasis. BSEP deficiency leads to severe cholestasis and hepatocellular carcinoma (HCC) in young children. Regardless of the etiology, chronic inflammation is the common pathological process for HCC development. Clinical studies have shown that bile acid homeostasis is disrupted in HCC patients with elevated serum bile acid level as a proposed marker for HCC. However, the underlying mechanisms remain largely unknown. In this study, we found that BSEP expression was severely diminished in HCC tissues and markedly reduced in adjacent nontumor tissues. In contrast to mice, human BSEP was regulated by farnesoid X receptor (FXR) in an isoform-dependent manner. FXR-α2 exhibited a much more potent activity than FXR-α1 in transactivating human BSEP in vitro and in vivo. The decreased BSEP expression in HCC was associated with altered relative expression of FXR-α1 and FXR-α2. FXR-α1/FXR-α2 ratios were significantly increased, with undetectable FXR-α2 expression in one third of the HCC tumor samples. A similar correlation between BSEP and FXR isoform expression was confirmed in hepatoma Huh7 and HepG2 cells. Further studies showed that intrahepatic proinflammatory cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α), were significantly elevated in HCC tissues. Treatment of Huh7 cells with IL-6 and TNF-α resulted in a marked increase in FXR-α1/FXR-α2 ratio, concurrent with a significant decrease in BSEP expression. CONCLUSION: BSEP expression is severely diminished in HCC patients associated with alteration of FXR isoform expression induced by inflammation. Restoration of BSEP expression through suppressing inflammation in the liver may reestablish bile acid homeostasis.

Study of the fingertip pattern as a tool for the identification of the dermatoglyphic trait in bronchial asthma.

INTRODUCTION: Bronchial Asthma is one of the most extensively studied respiratory diseases and its genetic basis is well established. Dermatoglyphic traits are formed under genetic control early in development but may be affected by environmental factors during first trimester of pregnancy. These patterns may represent the genetic makeup of an individual and therefore his/her predisposition to certain diseases. Patterns of dermatoglyphics have been studied in various congenital disorders like Down's syndrome, Klinefelter's syndrome and also in chronic diseases like Hypertension, Diabetes Mellitus etc. Epidermal ridge patterns of finger tips in bronchial asthma patients were studied to find out fingertip pattern as Dermatoglyphic features in patients of Bronchial Asthma; it's comparison and association if exists between normal and bronchial asthma patients and also to find use of fingertip pattern in early childhood as non-invasive anatomical marker for bronchial asthma in adulthood. METHODS: The study was conducted on clinically diagnosed all bronchial asthma patients attending OPD of Dr Ulhas Patil Medical College, Jalgaon. Matched controls were selected without any respiratory problem or any symptoms related to asthma from medical students, staff members and paramedical staff of hospital after taking the informed consent and permission from the institutional ethical committee. Data collection and fingertip prints were taken by ink and rolling finger method. Prints taken were analysed and tabulated; data was analysed by using statistical tests. RESULTS: Study shows that decrease in number of arches, increase in AFRC in patients as compared with controls. Also there were increased ulnar loops in male patients and increased Whorls and radial loops in female patients. CONCLUSION: The fingerprints can represent a non-invasive anatomical marker of bronchial asthma risk and facilitate early detection and effective management which is vital for selecting appropriate agents for treating infections.

Enhanced Nrf2 activity worsens insulin resistance, impairs lipid accumulation in adipose tissue, and increases hepatic steatosis in leptin-deficient mice.

The study herein determined the role of nuclear factor erythoid 2-related factor 2 (Nrf2) in the pathogenesis of hepatic steatosis, insulin resistance, obesity, and type 2 diabetes. Lep(ob/ob)-Keap1-knockdown (KD) mice, which have increased Nrf2 activity, were generated. Markers of obesity and type 2 diabetes were measured in C57Bl/6J, Keap1-KD, Lep(ob/ob), and Lep(ob/ob)-Keap1-KD mice. Lep(ob/ob)-Keap1-KD mice exhibited less lipid accumulation, smaller adipocytes, decreased food intake, and reduced lipogenic gene expression. Enhanced Nrf2 activity impaired insulin signaling, prolonged hyperglycemia in response to glucose challenge, and induced insulin resistance in Lep(ob/ob) background. Nrf2 augmented hepatic steatosis and increased lipid deposition in liver. Next, C57Bl/6J and Keap1-KD mice were fed a high-fat diet (HFD) to determine whether Keap1 and Nrf2 impact HFD-induced obesity. HFD-induced obesity and lipid accumulation in white adipose tissue was decreased in Keap1-KD mice. Nrf2 activation via Keap1-KD or sulforaphane suppressed hormone-induced differentiation and decreased peroxisome proliferator-activated receptor-γ, CCAAT/enhancer-binding protein α, and fatty acid-binding protein 4 expression in mouse embryonic fibroblasts. Constitutive Nrf2 activation inhibited lipid accumulation in white adipose tissue, suppressed adipogenesis, induced insulin resistance and glucose intolerance, and increased hepatic steatosis in Lep(ob/ob) mice.

Severe diabetes and leptin resistance cause differential hepatic and renal transporter expression in mice.

BACKGROUND: Type-2 Diabetes is a major health concern in the United States and other Westernized countries, with prevalence increasing yearly. There is a need to better model and predict adverse drug reactions, drug-induced liver injury, and drug efficacy in this population. Because transporters significantly contribute to drug clearance and disposition, it is highly significant to determine whether a severe diabetes phenotype alters drug transporter expression, and whether diabetic mouse models have altered disposition of acetaminophen (APAP) metabolites. RESULTS: Transporter mRNA and protein expression were quantified in livers and kidneys of adult C57BKS and db/db mice, which have a severe diabetes phenotype due to a lack of a functional leptin receptor. The urinary excretion of acetaminophen-glucuronide, a substrate for multidrug resistance-associated proteins transporters was also determined. The mRNA expression of major uptake transporters, such as organic anion transporting polypeptide Slco1a1 in liver and kidney, 1a4 in liver, and Slc22a7 in kidney was decreased in db/db mice. In contrast, Abcc3 and 4 mRNA and protein expression was more than 2 fold higher in db/db male mouse livers as compared to C57BKS controls. Urine levels of APAP-glucuronide, -sulfate, and N-acetyl cysteine metabolites were higher in db/db mice. CONCLUSION: A severe diabetes phenotype/presentation significantly altered drug transporter expression in liver and kidney, which corresponded with urinary APAP metabolite levels.

Alteration of hepatic but not renal transporter expression in diet-induced obese mice.

Drug pharmacokinetics can be altered in obese and diabetic subjects. In consideration of the prevalence of obesity and diabetes, characterization of transporter expression in mouse models of diabetes and obesity may be a useful tool to aid in prediction of altered drug pharmacokinetics or adverse drug reactions. It has been reported that ob/ob mice, which display a severe obesity and diabetes phenotype, exhibit multiple changes in drug transporter expression in liver and kidney. In the present study, the mRNA and protein expression of major drug transporters was determined in livers and kidneys of diet-induced obese (DIO) C57BL/6J male mice. The mice were fed a high-fat diet (HFD) (60% fat) from 6 weeks of age and display obesity, fatty liver, and mild hyperglycemia. The HFD diet increased expression of multidrug resistance-associated proteins Abcc3 and 4 mRNA and protein in liver by 3.4- and 1.4-fold, respectively, compared with that detected in control mice fed a low-fat diet (LFD). In contrast, Abcc1 mRNA and protein decreased by 50% in livers of DIO mice compared with those in livers to lean mice. The HFD did not alter transporter expression in kidney compared with the LFD. In summary, unlike ob/ob and db/db mice, DIO mice exhibited a selective induction of efflux transporter expression in liver (i.e., Abcc3 and 4). In addition, diet-induced obesity affects transporter expression in liver but not kidney in the C57BL/6J mouse model. These data indicate that hepatic transporter expression is only slightly altered in a model of mild diabetes and nonalcoholic fatty liver disease and obesity.