dinoprost and ciglitazone

Increased NAD(P)H oxidase-dependent free radical generation has been proposed to be a mechanism in glycerol-induced acute renal failure (ARF). Previously, we showed a PPARγ-mediated regulation of free radical generation in ARF. In this study, we examined NAD(P)H oxidase-dependent pathology in ARF and its connection with PPARγ using both Sprague-Dawley rats and gp91phox (+/-) mice. Male gp91phox (+/-) or wild type (+/+) mice were distributed into vehicle and ARF group (50% glycerol; 8 mL/kg bw; i.m.). Animals were placed in metabolic cages for 24 hr and were sacrificed under pentobarbital anesthesia. Urine, plasma and kidneys were processed for biochemical and molecular analysis. Glycerol doubled proteinuria in (+/+) mice (68 ± 4 mg/24 hr) but not in (+/-) mice (43 ± 9 mg/24 hr). This was associated with a markedly reduced creatinine excretion in (+/+) mice (Con: 0.6 ± 0.03 & ARF: 0.37 ± 0.02). Basal plasma and urinary NO was higher in (+/-) mice than the (+/+) type while plasma 8-isoprostane level was lower in (+/-) mice (WT: 165 ± 20; KO: 100 ± 15 pg/mL). Glycerol reduced UNOXV in both (+/+) and (+/-) mice although plasma NO was unchanged. Glycerol also doubled 8-isoprostane in (+/+) (363 ± 22 pg/mL) but not in (+/-) mice (152 ± 20 pg/mL) and this was associated with an increased NAD(P)H oxidase activity in the (+/+) mice. In ARF, PPARγ expression was reduced in (+/+) mice but increased in (+/-) mice. PPARγ activity was also reduced in (+/+) mice but was unchanged in (+/-) mice. We conclude that gp91phox contributes to NAD(P)H oxidase-mediated increased free radical generation in ARF and this may be via reduced PPARγ.

Topics: Acute Kidney Injury; Animals; Dinoprost; Free Radicals; Glycerol; Male; Membrane Glycoproteins; Mice; Mice, Knockout; NADPH Oxidase 2; NADPH Oxidases; Nitric Oxide; PPAR gamma; Rats, Sprague-Dawley; Reactive Oxygen Species; Thiazolidinediones; Transcription, Genetic

Peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear transcription factor, modulates vascular responses to angiotensin II (AII) or thromboxane A(2) (TxA(2)) via regulation of their gene/receptor. Increased vasoconstriction and deteriorating renal function in glycerol-induced acute renal failure (ARF) may be attributed to down-regulation of PPARgamma. In this study, we investigated the effect of ciglitazone (CG), a PPARgamma inducer, on AII and TxA(2) production and activity in glycerol-induced ARF. Vascular responses to AII or 9,11-dideoxy-11alpha,9alpha-epoxymethano prostaglandin F(2alpha) (U46619), a TxA(2) mimetic, were determined in preglomerular vessels following induction of ARF with glycerol. Renal damage and function were assessed in CG-treated (9 nmol/kg for 21 days) rats. PPARgamma protein expression and activity, which were significantly lower in ARF rats, were enhanced by CG (26 and 30%). CG also increased PPARgamma mRNA by 67 +/- 6%, which was reduced in ARF. In ARF, there was significant tubular necrosis and apoptosis, a 5-fold increase in proteinuria and a 2-fold enhancement in vasoconstriction to AII and U46619. CG reduced proteinuria (49 +/- 3%), enhanced Na(+) (124 +/- 35%) and creatinine excretion (92 +/- 25%), markedly diminished tubular necrosis, and reduced ARF-induced increase in AII (40 +/- 3%) and TxA(2) (39 +/- 2%) production, the attending increase in vasoconstriction to AII (36 +/- 2%) and U46619 (50 +/- 11%), and the increase in angiotensin receptor-1 (AT(1)) (23 +/- 3%) or thromboxane prostaglandin (TP) receptor (13 +/- 1%). CG reduced free radical generation by 55 +/- 14% while elevating nitrite excretion (65 +/- 13%). Our results suggest that enhanced activity of AII and TxA(2), increased AT(1) or TP receptor expression, and renal injury in glycerol-induced ARF are consequent to down-regulation of PPARgamma gene. CG ameliorated glycerol-induced effects through maintaining PPARgamma gene.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Acute Kidney Injury; Angiotensin II; Animals; Creatinine; Dinoprost; Gene Expression; Glycerol; Hypoglycemic Agents; Kidney Glomerulus; Male; Nitric Oxide; Nitrites; PPAR gamma; Proteinuria; Rats; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 1; Receptors, Thromboxane A2, Prostaglandin H2; Renal Artery; Sodium; Thiazolidinediones; Thromboxane A2; Thromboxane B2; Vasoconstriction

We have previously shown that nuclear factor-kappaB inhibition by adenovirus expressing mutated IkappaB-alpha or by proteasome inhibitor increases human articular chondrocytes sensibility to apoptosis. Moreover, the nuclear factor-kappaB inhibitor BAY11-7085, a potent anti-inflammatory drug in rat adjuvant arthritis, is itself a proapoptotic agent for chondrocytes. In this work, we show that BAY 11-7085 but not the proteasome inhibitor MG-132 induced a rapid and sustained phosphorylation of extracellular signal-regulated kinases (ERK1/2) in human articular chondrocytes. The level of ERK1/2 phosphorylation correlated with BAY 11-7085 concentration and chondrocyte apoptosis. 15-Deoxy-delta(12,14)-prostaglandin J2 (15d-PGJ2) and its precursor prostaglandin (PG) D2 but not PGE2 and PGF2alpha rescued chondrocytes from BAY 11-7085-induced apoptosis. 15d-PGJ2 markedly inhibited BAY 11-7085-induced phosphorylation of ERK1/2. BAY 11-7085 also induced ERK1/2 phosphorylation and apoptosis in human synovial fibroblasts, and these reactions were down-regulated by 15d-PGJ2. Further analysis in synovial fibroblasts showed that only molecules that suppressed BAY 11-7085-induced phosphorylation of ERK1/2 (i.e. 15d-PGJ2, PGD2, and to a lesser extent, MEK1/2 inhibitor UO126, but not prostaglandins E2 and F2alpha or peroxisome proliferator-activated receptor-gamma agonist ciglitazone) were able protect cells from apoptosis. These results suggested that the antiapoptotic effect of 15d-PGJ2 on chondrocytes and synovial fibroblasts might involve inhibition of ERK1/2 phosphorylation.

Topics: Annexin A5; Anti-Infective Agents; Apoptosis; Blotting, Western; Cartilage; Cartilage, Articular; Cell Survival; Cells, Cultured; Chondrocytes; Coloring Agents; Cysteine Endopeptidases; Dinoprost; Dinoprostone; Down-Regulation; Fibroblasts; Humans; I-kappa B Proteins; Immunologic Factors; Leupeptins; Mitogen-Activated Protein Kinases; Multienzyme Complexes; Mutation; NF-kappa B; NF-KappaB Inhibitor alpha; Nitriles; Phosphorylation; Prostaglandin D2; Proteasome Endopeptidase Complex; Receptors, Cytoplasmic and Nuclear; Sulfones; Synovial Membrane; Thiazolidinediones; Transcription Factors

The research described herein evaluates the expression and functional significance of peroxisome proliferator activator receptor-gamma (PPAR-gamma) on B-lineage cells. Normal mouse B cells and a variety of B lymphoma cells reflective of stages of B cell differentiation (e.g., 70Z/3, CH31, WEHI-231, CH12, and J558) express PPAR-gamma mRNA and, by Western blot analysis, the 67-kDa PPAR-gamma protein. 15-Deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)), a PPAR-gamma agonist, has a dose-dependent antiproliferative and cytotoxic effect on normal and malignant B cells as shown by [(3)H]thymidine and 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assays. Only PPAR-gamma agonists (thiazolidinediones), and not PPAR-alpha agonists, mimicked the effect of 15d-PGJ(2) on B-lineage cells, indicating that the mechanism by which 15d-PGJ(2) negatively affects B-lineage cells involves in part PPAR-gamma. The mechanism by which PPAR-gamma agonists induce cytotoxicity is via apoptosis, as shown by annexin V staining and as confirmed by DNA fragmentation detected using the TUNEL assay. Interestingly, addition of PGF(2alpha), which was not known to affect lymphocytes, dramatically attenuated the deleterious effects of PPAR-gamma agonists on B lymphomas. Surprisingly, 15d-PGJ(2) induced a massive increase in nuclear mitogen-activated protein kinase activation, and pretreatment with PGF(2alpha) blunted the mitogen-activated protein kinase activation. This is the first study evaluating PPAR-gamma expression and its significance on B lymphocytes. PPAR-gamma agonists may serve as a counterbalance to the stimulating effects of other PGs, namely PGE(2), which promotes B cell differentiation. Finally, the use of PGs, such as 15d-PGJ(2), and synthetic PPAR-gamma agonists to induce apoptosis in B-lineage cells may lead to the development of novel therapies for fatal B lymphomas.

Topics: Animals; Apoptosis; B-Lymphocytes; Cell Lineage; Cells, Cultured; Chromans; Dinoprost; Hypoglycemic Agents; Lymphoma, B-Cell; Male; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Inbred DBA; Prostaglandin D2; Receptors, Cytoplasmic and Nuclear; RNA, Messenger; Thiazoles; Thiazolidinediones; Transcription Factors; Troglitazone; Tumor Cells, Cultured