scholarly journals Induction of acyl-CoA oxidase and cytochrome P450IVA1 RNA in rat primary hepatocyte culture by peroxisome proliferators

1991 ◽  
Vol 280 (1) ◽  
pp. 249-253 ◽  
Author(s):  
D R Bell ◽  
C R Elcombe

We have characterized the induction of acyl-CoA oxidase and cytochrome P450IVA1 RNAs in a primary hepatocyte culture system in vitro, using a sensitive and specific RNAse protection assay. Hepatocytes were cultured with a maximal inducing dose of the peroxisome proliferator clofibric acid (1 mM), or vehicle control, for 4 days, and the level of RNAs compared with the level in rats which had been treated with corn oil or clofibric acid (300 mg/kg) for 4 days. The level of acyl-CoA oxidase and P450IVA1 RNAs in 4-day-old control hepatocytes was less than 2% of that in control liver. However, the level of these RNAs in RNA from treated hepatocytes was 61% of that in liver RNA from treated rats. Hepatocytes were treated with the potent peroxisome proliferator methylclofenapate (100 microM), and the induction of RNAs determined at various times after exposure. P450IVA1 RNA was significantly induced 1 h after dosing, rising to 34-fold above control after 8 h, whereas acyl-CoA oxidase RNA was not significantly induced until 4 h, increasing to 5.2-fold above control after 8 h. A similar time course of induction was seen after treatment of hepatocytes with 100 microM-nafenopin, 100 microM-methylclofenapate, 1 mM-clofibric acid or 1 mM-mono(ethylhexyl) phthalate, suggesting that the differential time course of induction of P450IVA1 and acyl-CoA oxidase RNAs is not related to the esterification, structure or potency of the peroxisome proliferator, but is intrinsic to the process of peroxisome proliferation. Hepatocytes were treated with methylclofenapate in the presence and absence of cycloheximide. P450IVA1 RNA was significantly induced by methylclofenapate in the presence of cycloheximide, rising to 17-fold above control after 8 h. However, no induction of acyl-CoA oxidase RNA was detected in the presence of cycloheximide. Therefore we characterize the induction of acyl-CoA oxidase and P450IVA1 RNAs in primary hepatocyte culture in vitro as a faithful model of the induction response in rat liver, and suggest that induction of P450IVA1 RNA is a primary event in the process of peroxisome proliferation.

1994 ◽  
Vol 301 (3) ◽  
pp. 753-758 ◽  
Author(s):  
P A Ram ◽  
D J Waxman

The role of steroids related to the adrenal androgen dehydroepiandrosterone (5-androstene-3 beta-ol-17-one; DHEA) in regulating the expression of peroxisomal and cytochrome P-450 4A (CYP4A) enzymes active in fatty acid metabolism was assessed using a primary rat hepatocyte culture system. Exposure of hepatocytes to the peroxisome proliferator, clofibric acid (10-250 microM), for 48-96 h led to substantial increases in CYP4A protein, CYP4A1, CYP4A2 and CYP4A3 mRNAs, and the mRNAs encoding both forms of peroxisomal acyl-CoA oxidase (ACOX-I and ACOX-II), as judged by Northern-blot analysis using gene-specific oligonucleotide probes. Although DHEA treatment in vivo is effective in inducing these mRNAs in rat liver, it had no effect in the cultured hepatocytes. In contrast, treatment of the cells with DHEA 3 beta-sulphate (DHEA-S; 10-250 microM) stimulated major increases in CYP4A and ACOX mRNA levels. Examination of several analogues indicated a preference for 3 beta-sulphate over 17 beta-sulphated steroids and the inactivity of a 3 alpha-hydroxy-17 beta-sulphate derivative (DHEA-S > 5-androstene-3 beta,17 beta-diol 3-sulphate approximately 5 alpha-androstene-3 beta-ol-17-one 3-sulphate > 5-androstene-3 beta, 17 beta,17 beta-diol 17-sulphate approximately 5 beta-androstane-3 alpha-ol-17-one 3-sulphate >> 5 alpha-androstane-3 alpha, 17 beta-diol 17-sulphate). Induction of CYP4A mRNAs by either DHEA-S or clofibric acid was partially blocked by structurally diverse Ca(2+)-channel antagonists (nicardipine, nifedipine and diltiazem; 50 microM), suggesting that both the steroidal and fibrate classes of CYP4A inducers stimulate peroxisomal-proliferative responses via a Ca(2+)-dependent pathway. Retinoic acid alone slightly induced CYP4A mRNAs but did not enhance the induction by clofibrate or DHEA-S. As DHEA-S corresponds to a physiologically important major circulating androgen, these findings suggest that it may serve as an endogenous regulator of hepatic peroxisome enzyme levels. They further suggest that Ca(2+)-channel blockers may be useful pharmacological tools for the further study of the underlying cellular mechanism whereby endogenous steroids and fibrate drugs induce peroxisome proliferation, and the relationship of these events to activation of the peroxisome proliferator-activated receptor.


2008 ◽  
Vol 37 (1) ◽  
Author(s):  
Swapna V. Shenvi ◽  
Brian M. Dixon ◽  
Kate Petersen Shay ◽  
Tory M. Hagen

2020 ◽  
Vol 105 (9) ◽  
pp. 2983-2995 ◽  
Author(s):  
Jie Yu ◽  
Sarah L Berga ◽  
Wei Zou ◽  
Augustine Rajakumar ◽  
Mingfei Man ◽  
...  

Abstract Context Implantation is a reproductive bottleneck in women, regulated by fluctuations in ovarian steroid hormone concentrations. However, other nuclear receptor ligands are modifiers of endometrial differentiation leading to successful pregnancy. In the present study we analyzed the effects of peroxisome-proliferator-activated receptor β/δ (PPARβ/δ) activation on established cellular biomarkers of human endometrial differentiation (decidualization). Objective The objective of this work is to test the effects of PPARβ/δ ligation on human endometrial cell differentiation. Design Isolated primary human endometrial stromal cells (ESCs) were treated with synthetic (GW0742) or natural (all trans-retinoic acid, RA) ligands of PPARβ/δ, and also with receptor antagonists (GSK0660, PT-S58, and ST247) in the absence or presence of decidualizing hormones (10 nM estradiol, 100 nM progesterone, and 0.5 mM dibutyryl cAMP [3′,5′-cyclic adenosine 5′-monophosphate]). In some cases interleukin (IL)-1β was used as an inflammatory stimulus. Time course and dose-response relationships were evaluated to determine effects on panels of well characterized in vitro biomarkers of decidualization. Results PPARβ/δ, along with estrogen receptor α (ERα) and PR-A and PR-B, were expressed in human endometrial tissue and isolated ESCs. GW0742 treatment enhanced hormone-mediated ESC decidualization in vitro as manifested by upregulation of prolactin, insulin-like growth factor-binding protein 1, IL-11, and vascular endothelial growth factor (VEGF) secretion and also increased expression of ERα, PR-A and PR-B, and connexin 43 (Cx43). RA treatment also increased VEGF, ERα, PR-A, and PR-B and an active, nonphosphorylated isoform of Cx43. IL-1β and PPARβ/δ antagonists inhibited biomarkers of endometrial differentiation. Conclusion Ligands that activate PPARβ/δ augment the in vitro expression of biomarkers of ESC decidualization. By contrast, PPARβ/δ antagonists impaired decidualization markers. Drugs activating these receptors may have therapeutic benefits for embryonic implantation.


1999 ◽  
Vol 31 (2) ◽  
pp. 293-299 ◽  
Author(s):  
Takayoshi Koura ◽  
Shuichi Kaneko ◽  
Eiki Matsushita ◽  
Hideki Ohno ◽  
Kyosuke Kaji ◽  
...  

2000 ◽  
pp. 71-78 ◽  
Author(s):  
A Gorla-Bajszczak ◽  
C Siegrist-Kaiser ◽  
O Boss ◽  
AG Burger ◽  
CA Meier

OBJECTIVE: Examination of the pattern of expression of peroxisome proliferator-activated receptor (PPAR) isoforms alpha and gamma in a model of obesity. DESIGN: Examination of adipose tissue and primary adipocyte cultures from lean and obese Zucker rats at different ages (28 days and 12 weeks). METHODS: mRNA levels were measured by RNase protection assay.RESULTS: The highest levels of PPARalpha and gamma mRNA were present in brown adipose tissue (BAT), followed by liver and white adipose tissue (WAT) for the alpha and gamma subtypes, respectively, at both ages examined. PPARalpha was expressed 100-fold higher in BAT compared with WAT, and PPARgamma mRNA levels were 2-fold higher in the WAT of obese compared with lean rats. PPARalpha and gamma expression was minimal in m. soleus, although higher levels of PPARgamma were found in the diaphragm. In marked contrast to the findings in vivo, virtually no PPARalpha mRNA could be detected in BAT cultures differentiated in vitro. CONCLUSION: PPARalpha and gamma are most highly expressed in BAT in vivo. However, PPARalpha is undetectable in brown adipose cells in vitro, suggesting that the expression of this receptor is induced by some external stimuli. In addition, the expression of PPARgamma was increased in WAT from young obese animals, compatible with an early adaptive phenomenon. Finally, the presence of PPARgamma mRNA is detectable only in particular muscles, such as the diaphragm, suggesting the possibility of an influence of fiber type on its expression, although exercise did not influence the expression of PPARgamma in other skeletal muscles.


1997 ◽  
Vol 3 (3) ◽  
pp. 289-301 ◽  
Author(s):  
William R. Wagner ◽  
Daniel J. Muzzio ◽  
Horatio R. Rilo ◽  
Timothy Deglau ◽  
Mohammad M. Ataai ◽  
...  

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