dihydropyridines and Chemical-and-Drug-Induced-Liver-Injury

The 1,4-dihydropyridines (DHPs) are one of the most frequently prescribed classes of antihypertensive monotherapeutic agents worldwide. In addition to treating hypertension, DHPs also exert other beneficial effects, including hepatoprotective effects. However, the mechanism underlying the hepatoprotection remains unclear.. Biochemical AlphaScreen and cell-based reporter assays were employed to detect the activities of DHPs towards FXR. A crystallographic analysis was adopted to study the binding modes of four DHPs in complex with FXR. Acetaminophen (APAP)-treated wild-type and FXR knockout mice were used to investigate the functional dependence of the effects of the selected DHPs on FXR.. A series of DHPs were uncovered as FXR ligands with different activities for FXR, suggesting FXR might serve as an alternative drug target for DHPs. The structural analysis illustrated the specific three-blade propeller binding modes of four DHPs to FXR and explained the detailed mechanisms by which DHPs bind to and are recognized by FXR. The results in mice demonstrated that cilnidipine protected the liver from APAP-induced injury in an FXR-dependent manner.. This study reports the crystal structures of FXR in complex with four DHPs, and confirms that DHPs exert hepatoprotection by targeting FXR.. Our research not only reveals valuable insight for the design and development of next-generation Ca

Topics: Acetaminophen; Analgesics, Non-Narcotic; Animals; Antihypertensive Agents; Calcium Channel Blockers; Chemical and Drug Induced Liver Injury; Dihydropyridines; HEK293 Cells; Humans; Liver; Male; Mice; Mice, Knockout; Models, Molecular; Protein Conformation; RNA-Binding Proteins

To determine if nuclear factor-kappaB (NF-kB) plays a role in Mallory body (MB) formation, quantitative real-time RT-PCR assay was used to measure liver NF-kappaB1/p105 mRNA levels in 4 different groups of mice. Group 1: mice given IP saline for 15 weeks; group 2: mice fed diethyl 1,4-dihydro-2,4,6,-trimethyl-3,5-pyridinedicarboxylate (DDC) for 10 weeks when MBs were formed; group3: mice fed DDC 10 weeks, then withdrawn 5 weeks when MBs disappeared; group 4: mice fed DDC 10 weeks, withdrawn 4 weeks, then fed DDC+chlormethiazole (CMZ) for 1 week when MBs again formed. The mRNA for p105 NF-kappaB expression was significantly increased in the livers of mice treated with DDC (group 2) and DDC+CMZ (group 4) compared with the control livers (group 1) as well as the drug-withdrawal livers (group 3). Primary cultures of hepatocytes from drug-primed mice (the group 4 mice were withdrawn for another 4 weeks when the MBs had disappeared) were studied. The hepatocytes from drug-primed mice were MB free when isolated and used for primary culture. MBs began to form spontaneously within their cytoplasm after 2-3 days of culture. The NF-kappaB inhibitor (NF-kappaBi), a cell-permeable quinazoline compound that acts as a potent inhibitor of NF-kappaB transcriptional activation, was added to the medium 3 h after planting the cultures of liver cells. No MBs formed in the cells treated with 10 microM, 1 microM, and 0.1 microM NF-kappaBi for 6 days. MBs still formed in the cells treated with 10 nM NF-kappaBi for 6 days. Both DDC-primed and normal control liver cells began to enlarge and elongate after a few hours of culture. In contrast, the cells treated with NF-kappaBi stayed polyhedral in shape just as they appeared prior to culturing. The level of NF-kappaB1/p105 mRNA significantly increased in DDC-primed hepatocytes after 24 h of culture and in normal control hepatocytes after 48 h of culture. In DDC-primed hepatocytes, NF-kappaBi 0.1 muM treatment for 6 days significantly decreased mRNA expression of Src, p105/NF-kappaB1, ERK1, MEKK1, and JNK1/2. In normal control liver cells, NF-kappaBi treatment decreased mRNA expression of Src and JNK1 and stimulated the mRNA expression of p105/NF-kappaB1 and Junk2. NF-kappaBi treatment significantly decreased the total ERK1/2 protein and further decreased the phosphorylated (activated) form of ERK1/2 in the cultured hepatocytes. The results indicate that the p105 NF-kappaB pathway which putatively regulates ERK at both the transcript

Topics: Animals; Antigens, Nuclear; Blotting, Western; Cells, Cultured; Chemical and Drug Induced Liver Injury; Chlormethiazole; Chromosomal Proteins, Non-Histone; Dihydropyridines; Enzyme Inhibitors; Hepatocytes; Inclusion Bodies; JNK Mitogen-Activated Protein Kinases; Liver; Liver Diseases; Male; MAP Kinase Kinase 4; MAP Kinase Kinase Kinase 1; Mice; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinase Kinases; Models, Biological; NF-kappa B; NF-kappa B p50 Subunit; Protein Precursors; Quinazolines; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction

Mallory body (MB) formation is a complex phenomenon seen in chronic liver disease. CYP2E1 may play a role in preventing MB formation since it is involved in the elimination of toxic drugs and chemicals. When mice were fed with diethyl-1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate (DDC) for 10 weeks, Mallory bodies (MBs) developed in the liver at the end of this period. When DDC feeding was combined with CMZ (an efficient in vivo CYP2E1 inhibitor), more MBs formed compared to DDC feeding alone. DDC was shown to be a suicide inhibitor of CYP2E1. The level of CYP2E1 protein in the liver was further reduced by the DDC and CMZ treatment when measured by Western blot. To test whether CYP2E1 reduced MB formation, CYP2E1 knockout mice and CYP2E1 overexpressed mice were fed with DDC or DDC and CMZ for 10 weeks. MB formation increased markedly in the liver of CYP2E1 knockout mice when fed with DDC only. CYP2E1 overexpressed mice showed an increase in MB formation when the mice were fed with the combination of DDC and CMZ where the amount of CYP2E1 was reduced to levels seen in wild type mice. It was concluded that CYP2E1 inhibits MB formation by increasing the rate of elimination of DDC and/or its toxic intermediates.

Topics: Animals; Blotting, Western; Chemical and Drug Induced Liver Injury; Chlormethiazole; Cytochrome P-450 CYP2E1; Dihydropyridines; Enzyme Inhibitors; Female; Fluorescent Antibody Technique; Hepatocytes; Inclusion Bodies; Liver Diseases; Male; Mice; Mice, Inbred C3H; Mice, Knockout; Ubiquitin

NC-1500 is a dihydropyridine type calcium channel blocker. The effect of NC-1500 on mice concanavalin A-induced hepatitis was examined. Treatment of mice with concanavalin A (Con A) caused elevation of plasma transaminase. Pretreatment of mice with NC-1500 (3, 10 and 30 mg/kg, p.o.) prevented this Con A-induced elevation of plasma transaminase. Treatment of mice with Con A induced tumor necrosis factor-alpha (TNF-alpha) mRNA expression in the liver. However, NC-1500 (30 mg/kg, p.o.) did not affect this Con A-induced TNF-alpha mRNA expression in the liver. The present results showed that NC-1500 inhibited Con A-induced hepatitis without affecting TNF-alpha mRNA expression in the liver.

Topics: Alanine Transaminase; Animals; Anti-Inflammatory Agents, Non-Steroidal; Aspartate Aminotransferases; Calcium Channel Blockers; Chemical and Drug Induced Liver Injury; Concanavalin A; Dihydropyridines; Disease Models, Animal; Female; Gene Expression; Glycyrrhizic Acid; Mice; Mice, Inbred BALB C; Naphthyridines; RNA, Messenger; Tumor Necrosis Factor-alpha

Topics: Aged; Calcium Channel Blockers; Chemical and Drug Induced Liver Injury; Cholestasis; Dihydropyridines; Humans; Male; Peritoneal Dialysis, Continuous Ambulatory

Chronic oral administration of oxodipine, a new calcium channel blocker, resulted in a reduction in the blood enzyme activity of alanine and aspartate aminotransferase. The reductions were both time and dose related. The decline in enzyme activities was accompanied by microscopic hepatic changes, which in the opinion of the authors should have been associated with an increase in the enzyme activities of alanine aminotransferase and aspartate aminotransferase. The effect was only partially reversed one month after the cessation of oxodipine treatment.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Calcium Channel Blockers; Chemical and Drug Induced Liver Injury; Constipation; Dihydropyridines; Dose-Response Relationship, Drug; Female; Liver; Male; Rats; Rats, Inbred F344