Hepatic expression of cytochrome P450 in Zucker diabetic fatty rats

Liver mitochondria-associated endoplasmic reticulum membrane proteomics for studying the effects of ZiBuPiYin recipe on Zucker diabetic fatty rats after chronic psychological stress

Type 2 diabetes mellitus (T2DM) is a complex metabolic disease with multiple etiologies, involving both genetic and environmental factors. With changes associated with modern life, increasing attention has been paid to chronic psychological stressors such as work stress. Chronic psychological stress can induce or aggravate diabetes mellitus, and conversely, with the deterioration of T2DM, patients often experience different degrees of depression, anxiety, and other negative emotions. In order to clarify the role of ZiBuPiYin recipe (ZBPYR) in regulating the liver mitochondria-associated endoplasmic reticulum membrane proteome to improve T2DM with chronic psychological stress, differentially expressed proteins (DEPs) were identified among Zucker lean littermates (control group), chronic psychological stress T2DM rats (model group), and ZBPYR administration rats (ZBPYR group) through iTRAQ with LC-MS/MS. Using Mfuzz soft clustering analysis, DEPs were divided into six different clusters. Clusters 1–6 contained 5, 68, 44, 57, 28, and 32 DEPs, respectively. Given that ZBPYR can alleviate T2DM symptoms and affect exploratory behavior during T2DM with chronic psychological stress, we focused on the clusters with opposite expression trends between model:control and ZBPYR:model groups. We screened out the DEPs in clusters 1, 3, and 4, which may be good candidates for the prevention and treatment of T2DM with chronic psychological stress, and further conducted bioinformatics analyses. DEPs were mainly involved in the insulin signaling pathway, oxidative phosphorylation, tricarboxylic acid cycle, amino acid metabolism, lysosome-related processes, and lipid metabolism. This may indicate the pathogenic basis of T2DM with chronic psychological stress and the potential therapeutic mechanism of ZBPYR. In addition, two key proteins, lysosome-associated protein (Lamp2) and tricarboxylic acid cycle-related protein (Suclg1), may represent novel biomarkers for T2DM with chronic psychological stress and drug targets of ZBPYR. Western blot analyses also showed similar expression patterns of these two proteins in liver MAMs of the model and ZBPYR groups.

The Effects of AT-533 and AT-533 gel on Liver Cytochrome P450 Enzymes in Rats

BACKGROUND AND OBJECTIVES

AT-533 is a novel heat shock protein 90 inhibitor, which exhibits various biological activities in vitro and in vivo. Cytochrome P450 (CYP) enzymes in the liver are involved in the biotransformation of drugs and considered to be essential indicators of liver toxicity. The aim of this study was to assess the effect of AT-533, either as active pharmaceutical ingredient or in gel form, on liver CYP enzymes.

METHODS

The effect of AT-533 or AT-533 gel on rat liver cytochrome P450 enzymes, including CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4, was analyzed using LC-MS/MS.

RESULTS

AT-533 and AT-533 gel did not significantly increase or reduce the enzymatic activity of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 at any treatment dose.

CONCLUSIONS

AT-533 and AT-533 gel did not have any effect on CYP activity and may be considered safe for external use in gel form, as an alternative to conventional treatment.

Fine particulate matter and vasoactive 20-hydroxyeicosatetraenoic acid: Insights into the mechanisms of the prohypertensive effects of particulate air pollution

BACKGROUND

Emerging evidence suggests that biological intermediates play an important role in initiating fine particulate matter (PM_2.5)-associated prohypertensive pathways, but sensitive biomarkers for this pathway are lacking.

AIM

To explore whether short-term exposure to PM_2.5 is associated with the concentration of 20-hydroxyeicosatetraenoic acid (20-HETE), a potent vasoactive lipid relevant to the pathophysiology of hypertension.

METHODS

In this longitudinal panel study, we repeatedly (up to seven times) measured the blood concentrations of 20-HETE in 120 adults living in Beijing, China. Ambient exposure metrics included the concentrations of hourly PM_2.5 mass and daily PM_2.5 constituents, including three carbonaceous components, eight water-soluble ions, and 16 trace elements. Linear mixed-effects models were used to examine the associations between the change in the 20-HETE concentration and short-term exposure to ambient PM_2.5 metrics after adjustment for age, sex, body mass index, behavioral exposure, socioeconomic characteristics, and meteorological factors.

RESULTS

The interquartile range (IQR) increase in the 7-15-hour-lag exposure to PM_2.5 (80 μg/m³) was associated significantly with a 5.3% (95% confidence interval [CI], 0.1-10.7%) to 6.5% (95% CI, 1.7-11.6%) increase in the blood concentration of 20-HETE. The magnitude of the association differed by age, sex, prediabetic status, obesity, and hypertensive status, with a significantly greater increase in 20-HETE observed among those with fasting plasma glucose concentrations ≥ 6.1 mmol/L. In addition to the PM_2.5 mass, the 20-HETE concentration was associated consistently with IQR increases in the 1-day lag exposure to organic carbon (5.7%), black carbon (9.5%), nitrate (3.9%), chloride (2.9%), copper (5.5%), zinc (4.7%), barium (4.1%), and lead (6.2%). The organic carbon estimate was robust in the two-pollutant models. Furthermore, increased 20-HETE correlated with elevated blood pressure (BP), although no mediation of 20-HETE on PM_2.5-associated BP change was found.

CONCLUSIONS

The 20-HETE blood concentration increased significantly in response to short-term exposure to ambient PM_2.5, which may be partly responsible for the prohypertensive effects of PM_2.5.

The Beneficial Additive Effect of Silymarin in Metformin Therapy of Liver Steatosis in a Pre-Diabetic Model

The combination of plant-derived compounds with anti-diabetic agents to manage hepatic steatosis closely associated with diabetes mellitus may be a new therapeutic approach. Silymarin, a complex of bioactive substances extracted from Silybum marianum, evinces an antioxidative, anti-inflammatory, and hepatoprotective activity. In this study, we investigated whether metformin (300 mg/kg/day for four weeks) supplemented with micronized silymarin (600 mg/kg/day) would be effective in mitigating fatty liver disturbances in a pre-diabetic model with dyslipidemia. Compared with metformin monotherapy, the metformin-silymarin combination reduced the content of neutral lipids (TAGs) and lipotoxic intermediates (DAGs). Hepatic gene expression of enzymes and transcription factors involved in lipogenesis (Scd-1, Srebp1, Pparγ, and Nr1h) and fatty acid oxidation (Pparα) were positively affected, with hepatic lipid accumulation reducing as a result. Combination therapy also positively influenced arachidonic acid metabolism, including its metabolites (14,15-EET and 20-HETE), mitigating inflammation and oxidative stress. Changes in the gene expression of cytochrome P450 enzymes, particularly Cyp4A, can improve hepatic lipid metabolism and moderate inflammation. All these effects play a significant role in ameliorating insulin resistance, a principal background of liver steatosis closely linked to T2DM. The additive effect of silymarin in metformin therapy can mitigate fatty liver development in the pre-diabetic state and before the onset of diabetes.

Proinflammatory lipid signals trigger the health effects of air pollution in individuals with prediabetes

Individuals with metabolic disorders exhibit enhanced susceptibility to the cardiovascular health effects of particulate air pollution, but the underlying mechanisms are not yet understood. We aim to assess whether changes in proinflammatory lipid signals are associated with fine particulate matter (PM_2.5) exposure in individuals with and without prediabetes. A longitudinal panel study was conducted in Beijing, China, and included 120 participants followed up over 589 clinical visits from August 2013 to February 2015. We measured 12 lipids derived from arachidonic acid pathways in blood samples of the participants via targeted lipidomic analyses. Ambient PM_2.5 concentrations were continuously monitored at a station for associations with the lipids. Among the 120 participants, 110 (mean [SD] age at recruitment, 56.5 [4.2] years; 31 prediabetics) who visited the clinic at least twice over the follow-up period were assigned exposure values of the outdoor residential PM_2.5 concentrations during the 1-14 days preceding each clinical visit. With an interquartile range increase in the 1-day-lag PM_2.5 exposure (64.0 μg/m³), the prediabetic group had consistently greater increases in the concentration of arachidonate metabolites derived from the cytochrome P450 (CYP450) pathway (5,6-DHET, 15.8% [95% CI, 3.5-29.7%]; 8,9-DHET, 9.7% [95% CI, 0.6-19.6%]; 11,12-DHET, 8.3% [95% CI, 1.9-15.1%]; 14,15-DHET, 7.4% [95% CI, 0.9-14.4%]; and 20-HETE, 8.9% [95% CI, 1.0-17.5%]), compared with the healthy group. Among CYP450-derived lipids, 14,15-DHET and 20-HETE significantly mediated 8% and 8% of the PM_2.5-associated increase in white blood cells, 10% and 13% of that in neutrophils, and 20% and 23% of that in monocytes, respectively, in the prediabetic group. In conclusion, proinflammatory lipid signals from CYP450 pathways triggered the health effects of particulate air pollution in individuals with prediabetes, suggesting that targeting lipid metabolism has therapeutic potential to attenuate or prevent the cardiovascular effects of air pollution in susceptible populations.

Effects of insulin treatment on hepatic CYP1A1 and CYP2E1 activities and lipid peroxidation levels in streptozotocin-induced diabetic rats

Reactive oxygen species (ROS) and lipid peroxidation (LPO) levels may increase in diabetic state and lead to oxidative stress, which plays a critical role in the progression of diabetes. There are various sources of ROS, including cytochrome P450 monooxygenases (CYP450s), which may be modulated in terms of their activities and expressions under diabetic conditions. This study is aimed to investigate the effects of streptozotocin-induced diabetes and insulin treatment on hepatic cytochrome P450 1A1 (CYP1A1) and cytochrome P450 2E1 (CYP2E1) activities and LPO levels. Methods: CYP1A1 and CYP2E1 activities were measured with ethoxyresorufin O-deethylase and p-nitrophenol hydroxylase activities, respectively. LPO levels were then corroborated via thiobarbituric acid reactive substances. Results: In diabetic rats, a marked 2.1- and 2.4-fold increase in hepatic CYP1A1 activity and 1.8- and 1.6-fold increase in hepatic CYP2E1 activity were observed compared to controls and insulin-treated diabetic rats, respectively. Hepatic LPO levels in diabetic rats did not significantly change compared to controls. However, in insulin-treated diabetic rats, LPO levels are 0.92- and 0.89-fold remarkably decrease compared to controls and diabetics, respectively. Conclusion: The present study suggests that insulin might have a useful role in the modulation of CYP1A1 and CYP2E1 activities as well as LPO levels in the liver of diabetic rats.

Imbalance of Drug Transporter-CYP450s Interplay by Diabetes and Its Clinical Significance

The pharmacokinetics of a drug is dependent upon the coordinate work of influx transporters, enzymes and efflux transporters (i.e., transporter-enzyme interplay). The transporter-enzyme interplay may occur in liver, kidney and intestine. The influx transporters involving drug transport are organic anion transporting polypeptides (OATPs), peptide transporters (PepTs), organic anion transporters (OATs), monocarboxylate transporters (MCTs) and organic cation transporters (OCTs). The efflux transporters are P-glycoprotein (P-gp), multidrug/toxin extrusions (MATEs), multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). The enzymes related to drug metabolism are mainly cytochrome P450 enzymes (CYP450s) and UDP-glucuronosyltransferases (UGTs). Accumulating evidence has demonstrated that diabetes alters the expression and functions of CYP450s and transporters in a different manner, disordering the transporter-enzyme interplay, in turn affecting the pharmacokinetics of some drugs. We aimed to focus on (1) the imbalance of transporter-CYP450 interplay in the liver, intestine and kidney due to altered expressions of influx transporters (OATPs, OCTs, OATs, PepTs and MCT6), efflux transporters (P-gp, BCRP and MRP2) and CYP450s (CYP3As, CYP1A2, CYP2E1 and CYP2Cs) under diabetic status; (2) the net contributions of these alterations in the expression and functions of transporters and CYP450s to drug disposition, therapeutic efficacy and drug toxicity; (3) application of a physiologically-based pharmacokinetic model in transporter-enzyme interplay.

Beneficial effects of troxerutin on metabolic disorders in non-obese model of metabolic syndrome

Background

Troxerutin (TRX) has a beneficial effect on blood viscosity and platelet aggregation, and is currently used for the treatment of chronic varicosity. Recently, TRX can improve lipid abnormalities, glucose intolerance and oxidative stress in high-fat diet-induced metabolic disorders. In this study, we tested the effect of TRX on metabolic syndrome-associated disorders using a non-obese model of metabolic syndrome–the Hereditary Hypertriglyceridaemic rats (HHTg).

Methods

Adult male HHTg rats were fed standard diet without or with TRX (150 mg/kg bwt/day for 4 weeks).

Results

Compared to untreated rats, TRX supplementation in HHTg rats decreased serum glucose (p<0.05) and insulin (p<0.05). Although blood lipids were not affected, TRX decreased hepatic cholesterol concentrations (p<0.01) and reduced gene expression of HMGCR, SREBP2 and SCD1 (p<0.01), involved in cholesterol synthesis and lipid homeostasis. TRX-treated rats exhibited decreased lipoperoxidation and increased activity of antioxidant enzymes SOD and GPx (p<0.05) in the liver. In addition, TRX supplementation increased insulin sensitivity in muscles and epididymal adipose tissue (p<0.05). Elevated serum adiponectin (p<0.05) and decreased muscle triglyceride (p<0.05) helped improve insulin sensitivity. Among the beneficial effects of TRX were changes to cytochrome P450 family enzymes. Hepatic gene expression of CYP4A1, CYP4A3 and CYP5A1 (p<0.01) decreased, while there was a marked elevation in gene expression of CYP1A1 (p<0.01).

Conclusion

Our results indicate that TRX improves hepatic lipid metabolism and insulin sensitivity in peripheral tissues. As well as ameliorating oxidative stress, TRX can reduce ectopic lipid deposition, affect genes involved in lipid metabolism, and influence the activity of CYP family enzymes.

Age-associated changes of cytochrome P450 and related phase-2 gene/proteins in livers of rats

Cytochrome P450s (CYPs) are phase-I metabolic enzymes playing important roles in drug metabolism, dietary chemicals and endogenous molecules. Age is a key factor influencing P450s expression. Thus, age-related changes of CYP 1–4 families and bile acid homeostasis-related CYPs, the corresponding nuclear receptors and a few phase-II genes were examined. Livers from male Sprague-Dawley rats at fetus (−2 d), neonates (1, 7, and 14 d), weanling (21 d), puberty (28 and 35 d), adulthood (60 and 180 d), and aging (540 and 800 d) were collected and subjected to qPCR analysis. Liver proteins from 14, 28, 60, 180, 540 and 800 days of age were also extracted for selected protein analysis by western blot. In general, there were three patterns of their expression: Some of the drug-metabolizing enzymes and related nuclear receptors were low in fetal and neonatal stage, increased with liver maturation and decreased quickly at aging (AhR, Cyp1a1, Cyp2b1, Cyp2b2, Cyp3a1, Cyp3a2, Ugt1a2); the majority of P450s (Cyp1a2, Cyp2c6, Cyp2c11, Cyp2d2, Cyp2e1, CAR, PXR, FXR, Cyp7a1, Cyp7b1. Cyp8b1, Cyp27a1, Ugt1a1, Sult1a1, Sult1a2) maintained relatively high levels throughout the adulthood, and decreased at 800 days of age; and some had an early peak between 7 and 14 days (CAR, PXR, PPARα, Cyp4a1, Ugt1a2). The protein expression of CYP1A2, CYP2B1, CYP2E1, CYP3A1, CYP4A1, and CYP7A1 corresponded the trend of mRNA changes. In summary, this study characterized three expression patterns of 16 CYPs, five nuclear receptors, and four phase-II genes during development and aging in rat liver, adding to our understanding of age-related CYP expression changes and age-related disorders.

High throughput metabolomics-proteomics investigation on metabolic phenotype changes in rats caused by Radix Scrophulariae using ultra-performance liquid chromatography with mass spectrometry

Radix Scrophulariae, a traditional Chinese herb, is used to treat various diseases, including H₂O₂-induced apoptosis in cardiomyocytes, HaCaT cells, hyperuricaemia, and depression. This study screened metabolites, proteins and common pathways to better understand both the therapeutic effects and side effects of this herb. Methods: Untargeted metabolomics based on UPLC-TOF-MS, coupled with proteomics based on nano-UPLC-Q-Exactive-MS/MS, were used to investigate the effects of R. Scrophulariae in rats. Fifty-one identified metabolites in urine samples and 76 modulated proteins in liver tissue were potential biomarkers for R. Scrophulariae treatment. The biomarkers and common pathways involved were steroid hormone biosynthesis, drug metabolism-cytochrome p450, drug metabolism-other enzymes, pentose and glucuronate interconversions, and starch and sucrose metabolism. Some biomarkers were beneficial for treating diseases such as cancer, tuberculosis and isovaleric acidaemia, while other biomarkers caused side effects. Metabolomic and proteomic analyses of R. Scrophulariae-treated rats provided valuable information on the biological safety and efficacy of using R. Scrophulariae clinically.

Radix Scrophulariae, a traditional Chinese herb, is used to treat various diseases, including H₂O₂-induced apoptosis in cardiomyocytes, HaCaT cells, hyperuricaemia, and depression.

Enhanced Platelet Response to Clopidogrel in Zucker Diabetic Fatty Rats due to Impaired Clopidogrel Inactivation by Carboxylesterase 1 and Increased Exposure to Active Metabolite

Clopidogrel (Clop), a thienopyridine antiplatelet prodrug, is metabolized by cytochrome P450s (CYPs) to an active metabolite, Clop-AM, and hydrolyzed by carboxylesterase (CES)1 to the inactive Clop-acid. Patients with type 2 diabetes (T2DM) tend to have a poor response to Clop due to reduced generation of Clop-AM. Whether a similar response occurs in the Zucker diabetic fatty (ZDF) rat, a commonly used animal model of T2DM, has not been explored. In this work, we compared ZDF and control rats for hepatic CES1- and CYP-mediated Clop metabolism; pharmacokinetics of Clop, Clop-AM, and Clop-acid; and the antiplatelet efficacy of Clop. In contrast to clinical findings, Clop-treated ZDF rats displayed significantly less (50%) maximum platelet aggregation at 4 hours than control rats; the enhanced efficacy was accompanied by higher formation of Clop-AM and lower formation of Clop-acid. In vitro studies showed that hepatic levels of CES1 protein and activity and Ces1e mRNA were significantly lower in ZDF than in control rats, as were the mRNA levels of CYP2B1/2, CYP2C11, and CYP3A2, and levels of CYP2B6-, CYP2C19-, and CYP3A4-related proteins and enzymatic activities in liver microsomes of ZDF rats. Interestingly, liver microsomes of ZDF rats produced higher levels of Clop-AM than that of control rats despite their lower CYP levels, although the addition of fluoride ion, an esterase inhibitor, enhanced Clop-AM formation in control rats more than in ZDF rats. These results suggest that the reduction in CES1-based Clop inactivation indirectly enhances Clop efficacy in ZDF rats by making more Clop available for CYP-mediated Clop-AM formation.

Short-term regulation of the hepatic activities of cytochrome P450 and glutathione S-transferase by nose-only cigarette smoke exposure in mice

The present study aimed to determine the effects of cigarette smoke on the regulation of hepatic cytochrome P450 (CYP) and glutathione S-transferase (GST) enzymes in male BALB/c mice exposed to nose-only cigarette smoke for 4 days. There were no significant increases in serum liver injury markers (alanine aminotransferase and aspartate aminotransferase) or oxidative stress (total antioxidant capacity, malondialdehyde, and glutathione disulfide/reduced glutathione) following cigarette smoke exposure, but malondialdehyde was elevated in the bronchoalveolar lavage fluid of smoke-exposed mice. Additionally, the hepatic microsomal protein levels of Cyp1a and Cyp2b, and the activities of ethoxyresorufin O-deethylase, pentoxyresorufin O-depenylase, and chlorzoxazone 6-hydrxylase, were elevated in smoke-exposed mice. Interestingly, the hepatic activities of GST toward 1-chloro-2,4-dinitrobenzene, 1,2-dichloro-4-nitrobenzene, and ethacrynic acid, but not cumene hydroperoxide were enhanced by cigarette smoke exposure, which was consistent with the increased expression levels of mu- and pi-class GSTs, but not alpha-class GSTs, observed in immunoblot analyses. These findings indicate that the short-term inhalation of cigarette smoke induces drug-metabolizing enzymes such as CYP1A, CYP2B, and mu/pi-class GSTs in the absence of hepatic injury and oxidative stress. Furthermore, smoking may alter hepatic drug metabolism, as well as the disposition and toxicity of xenobiotics, including some therapeutic drugs and cigarette smoke constituents.

Influence of diabetes on plasma pharmacokinetics and brain bioavailability of grape polyphenols and their phase II metabolites in the Zucker diabetic fatty rat

SCOPE

The effect of diabetes on the pharmacokinetics, bioavailability and brain distribution of grape polyphenols and select metabolites was studied in the Zucker diabetic fatty (ZDF) rat model.

METHODS AND RESULTS

(ZDF) rats and their lean controls (LN) were dosed with a Standardized Grape Polyphenol (SGP) Mixture consisting of grape seed extract, Concord grape juice and resveratrol (RES) by oral gavage for 10 days. An 8-h pharmacokinetic study was performed. After 24 h, a second dose of SGP was administered and 1 h later animals were sacrificed and brain tissue was harvested. Plasma, urine, and brain tissue were analyzed for grape polyphenols. ZDF rats exhibited significantly diminished C_max for all catechin, epicatechin, quercetin and resveratrol conjugated metabolites. Bioavailability was significantly lower in ZDF rats for methylated flavan-3-ol, RES, and quercetin metabolites. Significantly lower levels of metabolites of RES, quercetin, and flavan-3-ols were found in brains of ZDF rats. There was no significant difference between ZDF and LN in anthocyanins in plasma and no anthocyanins were detectable in brain extracts. ZDF rats showed significantly higher urinary excretion for all polyphenols.

CONCLUSION

Diabetes may alter the overall bioavailability of some polyphenols in plasma and brain in part due to higher urinary clearance.

Transcriptional Profile of Kidney from Type 2 Diabetic db/db Mice

Diabetic nephropathy (DN), a common diabetic microvascular complication, is characterized by progressive glomerular sclerosis and tubulointerstitial fibrosis. However, the underlying mechanisms involved in DN remain to be elucidated. We explored changes in the transcriptional profile in spontaneous type 2 diabetic db/db mice by using the cDNA microarray. Compared with control db/m mice, the db/db mice exhibited marked increases in body weight, kidney weight, and urinary albumin excretion. Renal histological analysis revealed mesangial expansion and thickness of the basement membrane in the kidney of the db/db mice. A total of 355 differentially expressed genes (DEGs) were identified by microarray analysis. Pathway enrichment analysis suggested that biological oxidation, bile acid metabolism, and steroid hormone synthesis were the 3 major significant pathways. The top 10 hub genes were selected from the constructed PPI network of DEGs, including Ccnb2 and Nr1i2, which remained largely unclear in DN. We believe that our study can help elucidate the molecular mechanisms underlying DN.