iridoids and 4-hydroxy-2-nonenal

BACKGROUND Revascularization is a successful therapeutic strategy for myocardial infarction. However, restoring coronary blood flow can lead to ischemia-reperfusion (I/R) injury. Low-dose 4-hydroxy-2-nonenal (HNE) therapy appears to play a key role in myocardial tolerance to I/R injury. We hypothesized that the positive effects of HNE on myocardial I/R injury may be UCP3-dependent. MATERIAL AND METHODS Adult male wild-type (WT) or UCP3 knockout (UCP3-/-) mice were pre-treated with the UCP inhibitor genipin or saline 1 h before ischemia and underwent 30-min coronary artery ligation followed by 24-h reperfusion. Mice were treated with intravenous HNE (4 mg/kg) or saline 5 min before reperfusion. Echocardiography was conducted to measure left ventricular end-diastolic posterior wall thickness (LVPWd), end-diastolic diameter (LVEDD), and fractional shortening (FS). Infarct size was measured by TTC staining. qRT-PCR and Western blotting were used to assess the expression of UCP3, UCP2, and the apoptosis markers cytochrome C and cleaved caspase-3. RESULTS HNE improved survival at 24 h post-MI in wild-type mice (p<0.05) but not in UCP3-/- mice. HNE preserved LVEDD and FS in WT mice (p<0.05) but not in UCP3-/- mice. HNE reduced infarct size in WT mice (p<0.05) but not in UCP3-/- mice. HNE upregulated UCP3 expression (p<0.05) but did not affect UCP2 expression. HNE reduced apoptosis marker expression in WT mice (p<0.05) but not in UCP3-/- mice. HNE's positive effects were abrogated by genipin in an UCP3-dependent manner. CONCLUSIONS Low-dose HNE reperfusion therapy attenuates murine myocardial I/R injury in an UCP3-dependent manner. These effects are abrogated by genipin in an UCP3-dependent manner.

Topics: Aldehydes; Animals; Apoptosis; Coronary Vessels; Heart; Iridoids; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardial Reperfusion; Myocardial Reperfusion Injury; Myocardium; Reperfusion Injury; Uncoupling Protein 3

Cisplatin (CP) is a potent and widely used chemotherapeutic agent. However, the clinical benefits of CP are compromised because it elicits nephrotoxicity and ototoxicity. In this study, we investigated the nephroprotective effects of the phytochemical genipin (GP) isolated from the gardenia (Gardenia jasminoides) fruit, using a murine model of CP-induced nephropathy. GP pretreatment attenuated the CP-induced renal tissue injury by diminishing the serum blood urea nitrogen, creatinine, and cystatin C levels, as well as those of kidney injury molecule-1. In addition, GP attenuated the CP-induced oxidative/nitrative stress by suppressing the activation of NADPH oxidase, augmenting the endogenous antioxidant defense system, and diminishing the accumulation of 4-hydroxynonenal and 3-nitrotyrosine in renal tissues. Furthermore, reduced levels of proinflammatory cytokines such as tumor necrosis factor-alpha and interleukin-1 beta indicated that CP-induced renal inflammation was mitigated upon the treatment with GP. GP also attenuated the CP-induced activation of mitogen-activated protein kinases, excessive activities of caspase-3/7 and poly(ADP-ribose) polymerase, DNA fragmentation, and apoptosis. When administered 12h after the onset of kidney injury, GP showed a therapeutic effect by ameliorating CP-induced nephrotoxicity. Moreover, GP synergistically enhanced the CP-induced cell death of T24 human bladder cancer cells. Collectively, our data indicate that GP attenuated the CP-induced renal tissue injury by abrogating oxidative/nitrative stress and inflammation and by blocking cell death pathways, thereby improving the renal function. Thus, our results suggest that the use of GP may be a promising new protective strategy against cisplatin-induced nephrotoxicity.

Topics: Aldehydes; Animals; Antioxidants; Apoptosis; Blood Urea Nitrogen; Caspase 3; Caspase 7; Cell Line, Tumor; Cisplatin; Creatinine; Cystatin C; Cytokines; Hepatitis A Virus Cellular Receptor 1; Humans; Inflammation; Iridoids; Kidney; Kidney Diseases; Male; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; Oxidative Stress; Poly(ADP-ribose) Polymerases; Tyrosine

Olive (Olea europaea) leaf, an important traditional herbal medicine, displays cardioprotection that may be related to the cellular redox modulating effects of its polyphenolic constituents. This study was undertaken to investigate the protective effect of the ethanolic and methanolic extracts of olive leaves compared to the effects of oleuropein, hydroxytyrosol, and quercetin as a positive standard in a carbonyl compound (4-hydroxynonenal)-induced model of oxidative damage to rat cardiomyocytes (H9c2). Cell viability was detected by the MTT assay; reactive oxygen species production was assessed by the 2',7'-dichlorodihydrofluorescein diacetate method, and the mitochondrial membrane potential was determined using a JC-1 dye kit. Phospho-Hsp27 (Ser82), phospho-MAPKAPK-2 (Thr334), phospho-c-Jun (Ser73), cleaved-caspase-3 (cl-CASP3) (Asp175), and phospho-SAPK/JNK (Thr183/Tyr185) were measured by Western blotting. The ethanolic and methanolic extracts of olive leaves inhibited 4-hydroxynonenal-induced apoptosis, characterized by increased reactive oxygen species production, impaired viability (LD50: 25 µM), mitochondrial dysfunction, and activation of pro-apoptotic cl-CASP3. The ethanolic and methanolic extracts of olive leaves also inhibited 4-hydroxynonenal-induced phosphorylation of stress-activated transcription factors, and the effects of extracts on p-SAPK/JNK, p-Hsp27, and p-MAPKAPK-2 were found to be concentration-dependent and comparable with oleuropein, hydroxytyrosol, and quercetin. While the methanolic extract downregulated 4-hydroxynonenal-induced p-MAPKAPK-2 and p-c-Jun more than the ethanolic extract, it exerted a less inhibitory effect than the ethanolic extract on 4-hydroxynonenal-induced p-SAPK/JNK and p-Hsp27. cl-CASP3 and p-Hsp27 were attenuated, especially by quercetin. Experiments showed a predominant reactive oxygen species inhibitory and mitochondrial protecting ability at a concentration of 1-10 µg/mL of each extract, oleuropein, hydroxytyrosol, and quercetin. The ethanolic extract of olive leaves, which contains larger amounts of oleuropein, hydroxytyrosol, verbascoside, luteolin, and quercetin (by HPLC) than the methanolic one, has more protecting ability on cardiomyocyte viability than the methanolic extract or each phenolic compound against 4-hydroxynonenal-induced carbonyl stress and toxicity.

Topics: Aldehydes; Animals; Antioxidants; Caspase 3; Cell Survival; In Vitro Techniques; Iridoid Glucosides; Iridoids; Mitochondria; Myocytes, Cardiac; Olea; Oxidative Stress; Phenylethyl Alcohol; Plant Extracts; Plant Leaves; Polyphenols; Protective Agents; Protein Serine-Threonine Kinases; Quercetin; Rats; Transcription Factors

Oxidative stress may play an important role in the pathogenesis of non-alcoholic steatohepatitis (NASH). Oleuropein, the active constituent of olive leaf, possesses anti-oxidant, hypoglycaemic, and hypolipidaemic activities. We aimed to investigate the preventive effects of olive leaf extract on hepatic fat accumulation in a rat model of NASH.. Spontaneously hypertensive/NIH-corpulent rats were fed a diet of AIN-93G with or without olive leaf extract (500, 1000, 2000 mg/kg diet, and control; 5 rats each) for 23 weeks. Serological and histopathological findings, anti-oxidative activity, and the alteration of fatty acid synthesis in the liver were evaluated.. Histopathologically, a diet of AIN-93G containing more than 1000 mg/kg olive leaf extract had a preventive effect for the occurrence of NASH. Thioredoxin-1 expression in the liver was more evident in rats fed this diet, and 4-hydroxynonenal expression in the liver was less evident in these rats. There were no significant differences in the activities of hepatic carnitine palmitoyltransferase, fatty acid synthase, malic enzyme, and phosphatidic acid phosphohydrolase among the groups.. Our data suggest that olive leaf extract may help prevent NASH, presumably through its anti-oxidative activity.

Topics: Aldehydes; Animal Feed; Animals; Antioxidants; Blood Chemical Analysis; Disease Models, Animal; Fatty Liver; Iridoid Glucosides; Iridoids; Liver; Male; Olea; Organ Size; Oxidative Stress; Plant Leaves; Pyrans; Rats; Rats, Inbred SHR; Thioredoxins

Previously, we reported that genipin, a herbal iridoid, had neuritogenic and neuroprotective actions on PC12 cells. Although nitric oxide (NO)-activated signalings were proposed to be neuritogenic, the neuroprotective action of genipin remains to be elucidated. From the standpoint of NO activation, we tested a possible protective mechanism through the nitrosative Kelch-like ECH-associated protein (Keap1)/NF-E2-related factor 2 (Nrf2)-antioxidant response element pathway in rat retinal ganglion cells (RGC-5 cells) in culture, and in vivo, against hydrogen peroxide and optic nerve injury (ONI), respectively, using a long-acting (1R)-isoPropyloxygenipin (IPRG001). IPRG001 induced NO generation and the expressions of antioxidative enzymes, such as heme oxygenase-1 (HO-1), in RGC-5 cells. The protective action of IPRG001 depended on HO-1 and NO induction. We found that S-nitrosylation of Keap1 by IPRG001 may contribute to translocation of Nrf2 to the nucleus and triggered transcriptional activation of antioxidative enzymes. Furthermore, apoptotic cells were increased and 4-hydroxy-2-nonenal was accumulated in rat retina following ONI. Pre-treatment with IPRG001 almost completely suppressed apoptosis and accumulation of 4-hydroxy-2-nonenal in RGCs following ONI accompanied by HO-1 induction. These data demonstrate for the first time that IPRG001 exerts neuroprotective action in RGCs in vitro and in vivo, through the Nrf2/antioxidant response element pathway by S-nitrosylation against oxidative stress.

Topics: Aldehydes; Animals; Antioxidants; Blotting, Western; Cell Death; Cell Line; Chromatin; Coloring Agents; Cysteine Proteinase Inhibitors; Heme Oxygenase-1; Humans; Immunohistochemistry; Immunoprecipitation; In Situ Nick-End Labeling; Intracellular Signaling Peptides and Proteins; Iridoid Glycosides; Iridoids; Kelch-Like ECH-Associated Protein 1; NF-E2-Related Factor 2; Nitric Oxide; Oxidative Stress; Rats; Rats, Sprague-Dawley; Response Elements; Retinal Ganglion Cells; Reverse Transcriptase Polymerase Chain Reaction; RNA; RNA, Small Interfering; Signal Transduction; Tetrazolium Salts; Thiazoles

Uncoupling protein 2 (UCP2) negatively regulates insulin secretion. UCP2 deficiency (by means of gene knockout) improves obesity- and high glucose-induced beta cell dysfunction and consequently improves type 2 diabetes in mice. In the present study, we have discovered that the small molecule, genipin, rapidly inhibits UCP2-mediated proton leak. In isolated mitochondria, genipin inhibits UCP2-mediated proton leak. In pancreatic islet cells, genipin increases mitochondrial membrane potential, increases ATP levels, closes K(ATP) channels, and stimulates insulin secretion. These actions of genipin occur in a UCP2-dependent manner. Importantly, acute addition of genipin to isolated islets reverses high glucose- and obesity-induced beta cell dysfunction. Thus, genipin and/or chemically modified variants of genipin are useful research tools for studying biological processes thought to be controlled by UCP2. In addition, these agents represent lead compounds that comprise a starting point for the development of therapies aimed at treating beta cell dysfunction.

Topics: Adenosine Triphosphate; Aldehydes; Animals; Drugs, Chinese Herbal; Glucose; Heterocyclic Compounds, 3-Ring; Insulin; Insulin Secretion; Insulin-Secreting Cells; Ion Channels; Iridoid Glycosides; Iridoids; Islets of Langerhans; Male; Membrane Transport Proteins; Mice; Mice, Knockout; Mice, Obese; Mitochondria; Mitochondrial Membranes; Mitochondrial Proteins; Molecular Conformation; Obesity; Potassium Channels; Protons; Pyrans; Uncoupling Protein 2