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Endocrinology Vol. 143, No. 9 3276-3283
Copyright © 2002 by The Endocrine Society

ARTICLE

Cyclooxygenase 2 Pathway Mediates IL-1ß Regulation of IL-1{alpha}, -1ß, and IL-6 mRNA Levels in Leydig Cell Progenitors

Laurence Walch and Patricia L. Morris

Population Council and The Rockefeller University, New York, New York 10021

Address all correspondence and requests for reprints to: Dr. Patricia L. Morris, Center for Biomedical Research, Population Council and The Rockefeller University, 1230 York Avenue, New York, New York 10021. E-mail: p-morris{at}popcbr.rockefeller.edu.


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Prostanoids are arachidonic acid (AA) metabolites derived from the cyclooxygenase (COX1 and COX2 isozymes) pathway and are involved in signal transduction pathways activated by distinct ILs. Although COX1 is the constitutive isoform of COX, IL-1ß is a potent inducer of COX2 expression in distinct cell types. This study was designed to determine whether cyclooxygenases could mediate endogenous cytokine regulation in rat progenitor Leydig cells. COX and IL (IL-1{alpha}, IL-1ß, and IL-6) mRNAs were measured by PCR and real-time PCR analyses, respectively. COX function was assessed using COX activity inhibitors: indomethacin (INDO; COX1 and COX2 inhibitor) and NS-398 (COX2 selective inhibitor). Our data indicate that endogenous progenitor COX1 mRNA levels are low and are not regulated by IL-1ß. In contrast, COX2 mRNA is induced by IL-1ß at 6, 9, and 24 h. IL-1ß induction of IL mRNAs was in part significantly impaired in the presence of INDO or NS-398. Among the prostanoids tested, prostaglandin E2 (PGE2), PGF2{alpha}, and carbaprostacyclin reversed the INDO inhibition of IL production. PGs alone have no (IL-1{alpha} and IL-1ß) or a modest (IL-6) effect on IL mRNA levels. PGE2, PGF2{alpha}, and PGI2 measurements show that IL-1ß treatment significantly increases progenitor Leydig cell production of these PGs. Taken together, our data demonstrate that this COX2 cascade is a regulator of cytokines in Leydig progenitors.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
CYCLOOXYGENASE (COX) is the enzyme that catalyzes the rate-limiting step of the prostanoid cascade (Fig. 1Go). Arachidonic acid (AA) is converted by COX to prostaglandin H2 (PGH2) (1). PGH2 is then metabolized by different synthases into more biologically active products, the prostanoids, which include the PGs (PGD2, PGE2, PGF2{alpha}, and PGI2) and thromboxane (TXA2). There are two distinct isoforms of COX: COX1 and COX2. COX1 displays the characteristics of a housekeeping gene. Although higher levels of that enzyme may be found in several specific tissues and cells, including endothelium, seminal vesicles, monocytes, and platelets, COX1 is constitutively expressed in most tissues (1). In contrast, COX2 expression is barely detected at a constitutive level and is markedly inducible in specialized cell types (1). In particular tissues, COX2 regulates specific physiological functions, such as the inflammatory process, ovulation, implantation, perinatal kidney development, ductus arteriosus remodeling, or ulcer healing (2). COX1 and COX2 activities are differentially inhibited by nonsteroidal anti-inflammatory drugs. For example, aspirin and indomethacin (INDO) inhibit both enzymes, whereas NS-398 is a selective inhibitor for COX2 (3, 4).



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  		Figure 1. A schematic representation of the conversion of AA to prostanoids via the COX pathway.

 
In the testis, Leydig cells are devoted to the production of testosterone, the hormone essential for spermatogenesis. In adult Leydig cells and the immortalized MA-10 Leydig tumor cell line, the regulatory effect of AA on steroid hormone biosynthesis has been demonstrated. AA alone can increase testosterone release and mediate the testosterone release induced by LH, hCG, and GnRH (5, 6, 7, 8, 9, 10, 11, 12). However, INDO does not inhibit the steroidogenic effect of AA (6, 12, 13). These results indicate that endogenous COX metabolites are not involved in AA-induced steroidogenic effects in adult Leydig cells. Actually, evidence for the implication of AA metabolites derived from the lipoxygenase pathway (leukotrienes) has been provided by several studies (5, 6, 12, 13).

Adult rat Leydig cells in culture release PGE2, and this release is inhibited by INDO (14). Some studies have provided evidence for increased PGE2 release in Leydig cells treated with AA, pituitary adenylate cyclase-activating polypeptide, and endothelin (8, 14, 15, 16). To date, no physiological role for PGE2 has been identified by these studies.

The human and rat testes produce IL-1 in vivo (17, 18). PGE2 release is induced by IL-1 in cultured adult rat Leydig cells (19). The mechanism by which IL-1 increases PGE2 production in these cells is unknown. Whether COX2 is induced in Leydig cells by IL-1 or other proinflammatory agents was not investigated. In adult Leydig cells, IL-1 has been shown to have either a stimulatory or no effect on basal testosterone production (20). In contrast, IL-1 inhibits LH/hCG and/or cAMP-stimulated testosterone production (20). Calkins et al. (19) have shown that INDO slightly reversed the IL-1 inhibition of hCG-induced testosterone release by adult rat Leydig cells. These results suggest that prostanoids in part mediate the IL-1 inhibitory effect on steroidogenesis in these cells.

Khan and colleagues (21) have shown that IL-1ß stimulates DNA synthesis in Leydig cells isolated from prepubertal rats, e.g. immature Leydig cells, but not in adult Leydig cells. IL-1ß was shown to increase LH-induced steroidogenesis in immature rat Leydig cells (22). Furthermore, IL-6 receptors were demonstrated in Leydig cells freshly isolated and purified from prepubertal rats (23). Taken together, these results indicate that developmentally the Leydig cell is responsive to IL. It has been proposed that these cytokines may play a physiological role in the paracrine/autocrine regulation of pubertal development of Leydig cells (24, 25, 26). IL-1 is a potent inducer of cytokine expression in the Leydig cells at latter stages of maturation (17, 27, 28, 29, 30, 31). In murine macrophages and the rat immature ovary, COX activity was shown to be involved in the production of IL during inflammation (32, 33, 34). The aim of the present study was to determine whether Leydig progenitors at an early stage of development respond to IL-1 with increased steady state mRNA cytokine levels. Furthermore, the levels of COX2 mRNA and the role(s) of COX2 and its metabolites in IL-1 signaling were investigated in progenitor Leydig cells (PLC).


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Cell preparation
PLC were prepared from 18-d-old Sprague Dawley rats [Crl: CD(Sprague Dawley)BR-CD, Charles River Laboratories, Inc., Kingston, NY] modified from the procedures described previously (35, 36). Briefly, after collagenase/dispase (Roche, Mannheim, Germany) dissociation, a fraction enriched in PLC was isolated using a Percoll density gradient separation (Amersham Pharmacia Biotech, Uppsala, Sweden). The purity of the PLC preparations was assessed using 3{alpha}-hydroxysteroid dehydrogenase (3{alpha}-HSD) immunocytochemistry and 3ß-HSD histochemistry as previously described (35). On isolation, the Leydig cell progenitors isolated from d-18 testes were macrophage free; 30 ± 1% were lightly positive for 3ß-HSD, and the remaining cells were strongly or weakly 3{alpha}-HSD positive (n = 8). The cells were cultured for 1 d in serum-free medium supplemented with 0.1% fetal bovine serum. PLC were rinsed twice with fresh serum- and phenol red-free culture medium and then treated with IL-1ß (10 ng/ml) in the absence (6, 9, or 24 h) or presence (24 h) of INDO (10 µM) or NS-398 (1 or 10 µM). Cells may also have been treated with PGs (10 µM) in the absence (for 18 h) or presence (for 24 h) of IL-1ß (10 ng/ml) and INDO (10 µM). The doses of IL-1ß and PGs were selected based on several similar studies that showed their maximal effects (37, 38, 39, 40). Doses of COX inhibitors were chosen based on studies that demonstrated their specificity and effectiveness at these concentrations (41, 42, 43). Procedures involving the use of animals strictly followed the Guidelines for the Care and Use of Laboratory Animals set forth by the NIH.

Total RNA extraction
Total RNA was extracted from PLC using the TRIzol reagent (Life Technologies, Inc., Grand Island, NY) according to the manufacturer’s instructions. RNA was measured using 260/280 UV spectrophotometry.

RT-PCR
Total RNA (1 µg) was reverse transcribed for 15 min at 42 C with 2.5 U/µl Moloney murine leukemia virus reverse transcriptase (PE Applied Biosystems, Foster City, CA). RT was performed in a 20-µl mixture containing 5 mM MgCl2, 1x PCR buffer II, 1 mM of each deoxy-NTP, 1 U/µl ribonuclease inhibitor, and 2.5 mM random hexamers. Samples were then denatured for 5 min at 99 C. A no-template control was performed for each experiment, establishing the absence of genomic contamination of the samples.

PCR was performed by using 1 µl of each RT product as a template. The following primers were used: COX1 sense primer, 5'-CCCAGAGTCATGAGTCGAAGGAG-3'; antisense primer, 5'-CAGGCGCATGAGTACTTCTCGG-3' (353-bp product) (44); COX2 sense primer, 5'-GCAAATCCTTGCTGTTCCAATC-3'; antisense primer, 5'-GGAGAAGGCTTCCCAGCTTTTG-3' (335-bp product) (44); and steroidogenic acute regulatory protein (StAR) sense primer, 5'-GCTCTGATGACACCACTCTGC-3'; antisense primer, 5'-GTGGTAGACCAGCCCATGGA-3' (276-bp product). AmpliTaq DNA polymerase (PE Applied Biosystems) was used at 25 mU/µl. The PCR reaction mixture (25 µl) contained 2 mM MgCl2, 1x PCR buffer II, and each primer at 0.2 µM. Amplification was performed in a programable thermal controller (model PTC-100, MJ Research, Inc., Watertown, MA). The samples were first denatured at 95 C for 2 min, followed by 30 PCR cycles; the temperature profile was 95 C for 30 sec, 60 C for 30 sec, and 72 C for 1 min and 30 sec. After the last cycle, an additional extension incubation of 7 min at 72 C was performed.

After amplification, PCR products (5 µl of each sample) were subjected to size separation by polyacrylamide gel (4–20% Tris/boric acid/EDTA gels, Novex, San Diego, CA). The bands were visualized by UV fluorescence after staining with ethidium bromide (2.5 µg/ml) for 15 min. Densitometric analysis was performed using the PC version of NIH Image software (Scion Image) after photography with a computer-assisted camera (Kodak, Rochester, NY).

Real-time PCR
Real-time PCR (TaqMan) analysis was used for relative quantitation of mRNA levels using a standard curve method. The detection of IL mRNAs was performed using proprietary predeveloped TaqMan primers and probes (PE Applied Biosystems). Real-time PCR analyses were conducted to quantitatively determine the levels of rat IL-1{alpha}, IL-1ß, and IL-6 mRNAs (6-carboxy-fluorescein-labeled probes) with 18S ribosomal RNA (VIC-labeled probe) used to normalize the data.

TaqMan reactions were set up in optical 96-well reaction plates by adding 24 µl of a mix containing 12.5 µl TaqMan Universal PCR Master Mix 2x, 2.5 µl of primers and probes (10x, according to the manufacturer’s instructions), and 9 µl autoclaved water. One microliter of RT samples prepared as described above was subsequently added to each well. The reactions were set up in triplicate.

The real-time fluorescence-monitored PCR reactions were performed using a PE Applied Biosystems model 7700 Sequence Detection System. The temperature profile was 50 C for 2 min, 95 C for 10 min, and then 95 C for 15 sec and 60 C for 1 min for 40 cycles. Using the manufacturer’s software, a threshold above the noise was chosen, and the cycle number (CT) at which fluorescence, generated by the cleavage of the probe, exceeded the threshold was determined for each well. For each real-time PCR analysis, a standard curve was generated by six 2-fold serial dilutions in water of the RT samples corresponding to the 24-h treatment of PLC with IL-1ß. CT values were compared with the standard curve after linear regression analysis. Experimental samples were diluted 3-fold for comparison with the standard curve. A no-template control was performed for each reaction in duplicate.

PG ELISA
Measurements of PGs in PLC culture medium were performed using ELISA kits according to the manufacturer’s instructions (Cayman Chemical, Ann Arbor, MI). Detection limits for PGE2, PGF2{alpha}, and 6-keto-PGF1{alpha} were 7.8, 3.9, and 15.6 pg/ml, respectively.

Data analysis
Densitometric analyses are expressed in arbitrary units. Real-time PCR data are expressed as a percentage of the IL-1ß 24-h response. All results are the mean ± SEM derived from the number of different experiments as indicated (n). Statistical analyses were performed using t test or paired t test, with a confidence level of 95%.

Drugs
PGD2, PGE2, PGF2{alpha}, carbaprostacyclin (cPGI2; pentanoic acid, 5-[hexahydro-5-hydroxy-4-(3-hydroxy-1-octenyl)-2(1H)-pentalenylidene]-,[3{alpha}S-[2E,3{alpha},4{alpha}(1E,3R*),5ß,6{alpha}]]-), U46619 (5-heptenoic acid, 7-[6-(3-hydroxy-1-octenyl)-2-oxabicyclo[2.2.1]hept-5-yl]-,[1R-[1{alpha},4{alpha},5ß(Z),6{alpha}(1E,3S*)]]-), and NS-398 (N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide) were purchased from Cayman Chemical. INDO [1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid] was obtained from Sigma (St. Louis, MO). Recombinant mouse IL-1ß was purchased from R\|[amp ]\|D Systems, Inc. (Minneapolis, MN). PGs and COX inhibitors were dissolved in dimethylsulfoxide (DMSO), and subsequent dilutions, as needed, were performed in serum- and phenol red-free medium on the day of the experiment. DMSO alone was used as vehicle in all plates as required. The final DMSO concentrations varied from 0.3–0.06%. IL-1ß was initially reconstituted in a solution of 0.1% BSA in PBS; the final BSA concentration was 0.0001%.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
To determine whether COX mRNAs are expressed in PLC, the cells were treated with or without IL-1ß (10 ng/ml) for various time periods up to 24 h. Total RNAs were extracted, and COX mRNAs were determined using RT-PCR. As no changes in steady state levels of StAR mRNA were observed in IL-1ß-treated PLC, StAR levels were used to normalize the results. Using RT-PCR, our data indicate that in PLC COX1 mRNA levels are at the limits of detection (using 1–10 µl reverse transcriptase). These low levels of COX1 mRNA are unchanged after IL-1ß treatment (data not shown). In contrast, IL-1ß treatment induces COX2 mRNA at 6, 9, and 24 h (Fig. 2Go). The effect(s) of long-term treatment (24 h) was further evaluated. To further investigate whether a product resulting from increased COX1 and/or COX2 activity is involved in the IL-1ß regulation of COX2 mRNA levels, PLC were treated for 24 h with IL-1ß in the absence or presence of INDO (10 µM) or NS-398 (1 or 10 µM). The results shown (Fig. 3Go) demonstrated that neither INDO nor NS-398 significantly modified 24-h COX2 mRNA induction by IL-1ß.



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  		Figure 2. IL-1ß induces COX2 mRNA in progenitors. PLC were cultured for 6, 9, or 24 h without [control (Ct)] or with IL-1ß (10 ng/ml). Total RNA were extracted, and cDNAs were amplified by RT-PCR using primers for COX2 (A) or primers for StAR (B). C, Densitometric analysis was performed. COX2 results are normalized with StAR values and are expressed as arbitrary units. A representative experiment is shown.

 


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  		Figure 3. Effects of INDO and NS-398 on COX2 mRNA induction by IL-1ß. PLC were cultured for 24 h without [control (Ct)] or with IL-1ß (10 ng/ml) in the absence (Veh) or presence of INDO (10 µM) or NS-398 (1 or 10 µM). Total RNAs were extracted, and cDNAs were amplified by RT-PCR using primers for COX2 (A) or StAR (B). C, Densitometric analysis was performed. COX2 results are normalized with StAR values and are expressed as arbitrary units. Results are the mean ± SEM from three different experiments. *, Significant difference from the CT value (by paired t test).

 
Experiments were performed to determine the effect of IL-1ß on levels of cytokine mRNAs in PLC. Progenitors were cultured for 24 h with or without IL-1ß (10 ng/ml), total RNAs were extracted, and IL-1{alpha}, IL-1ß, and IL-6 mRNAs were evaluated by real-time PCR. The three mRNAs are each significantly induced by IL-1ß (Fig. 4Go). The effects of both COX activity inhibitors, INDO (10 µM) and NS-398 (1 or 10 µM), on the regulation of cytokine mRNAs by IL-1ß were next examined. The results shown (Fig. 4Go) demonstrate that INDO as well as NS-398 significantly inhibit, in part, the IL-1ß up-regulation of IL-1{alpha} (3-fold), IL-1ß (3-fold), and IL-6 (2-fold). There is no significant difference between the effect of INDO and that of NS-398.



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  		Figure 4. Effects of INDO and NS-398 on IL mRNA induction by IL-1ß in progenitors. PLC were cultured for 24 h without [control (Ct)] or with IL-1ß (10 ng/ml) in the absence (Veh) or presence of INDO (10 µM) or NS-398 (1 or 10 µM). Total RNAs were extracted, and cDNAs were amplified by real-time RT-PCR using specific primers and probes for IL-1{alpha} (A), IL-1ß (B), or IL-6 (C). Results are the mean ± SEM from four different experiments. Data are normalized with 18S values and are expressed as a percentage of the IL-1ß 24-h response. *, Significant difference from the IL-1ß response (by paired t test).

 
To further evaluate the involvement of COX metabolites on the regulation of PLC cytokine mRNA levels, progenitors were treated for 18 h in the absence or presence of PGs (10 µM): PGE2, PGF2{alpha}, or cPGI2 (a stable analog of PGI2). The steady state levels of IL-1{alpha}, IL-1ß, and IL-6 mRNAs were evaluated using real-time PCR. These data are shown in Fig. 5Go. The three PGs did not modify the mRNA levels of IL-1{alpha} and IL-1ß. In contrast, IL-6 mRNA was significantly induced by PGE2, PGF2{alpha}, and cPGI2 in the same range (i.e. ~15% of the IL-1ß response measured after a 24-h treatment). Subsequently, the effect(s) of the different PGs (10 µM) was tested on cells concomitantly treated with IL-1ß (10 ng/ml) and INDO (10 µM) for 24 h. Real-time PCR data demonstrated that PGs at the least restored the inhibition of the IL-1{alpha}, IL-1ß, and IL-6 mRNA induction by IL-1ß due to INDO (Fig. 6Go). In PLC treated with IL-1ß (10 ng/ml) and INDO (10 µM), PGF2{alpha} and PGE2 were the most potent factors of those prostanoids tested that restored IL-1{alpha} and IL-1ß mRNA levels. Interestingly, cPGI2 was selectively effective in restoring IL-6 mRNA levels (P < 0.03). In either case, U46619 (a TXA2-mimetic agonist) and PGD2 either did or did not have a modest, but significant, effect (P < 10-6).



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  		Figure 5. Effect of PGs on the mRNA levels of ILs in progenitors. PLC were cultured for 18 h without [control (Ct)] or with PGE2, PGF2{alpha}, or cPGI2 (10 µM). Total RNA was extracted, and cDNAs were amplified by real-time RT-PCR using specific primers and probes for IL-1{alpha} (A), IL-1ß (B), or IL-6 (C). Results are the mean ± SEM from three different experiments. Data are normalized with 18S values and are expressed as a percentage of the IL-1ß 24-h response. *, Significant difference from similar values obtained in absence of PGs [control (Ct); by paired t test].

 


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  		Figure 6. Effect of PGs on steady state levels of IL mRNAs in PLC treated with IL-1ß and INDO. PLC were cultured for 24 h without [control (Ct)] or with IL-1ß (10 ng/ml) in the absence or presence (Veh) of INDO (10 µM). PGs (10 µM) were added concomitantly with IL-1ß (10 ng/ml) and INDO (10 µM). Total RNAs were extracted, and cDNAs were amplified by real-time RT-PCR using particular primers and probes for IL-1{alpha} (A), IL-1ß (B), or IL-6 (C). Results are the mean ± SEM from (n) individual experiments as indicated in C. Data are normalized with 18S values and are expressed as a percentage of the IL-1ß 24-h response. *, Significant difference from similar values obtained in the presence of IL-1ß and INDO (Veh; by paired t test).

 
Finally, the three potent PGs shown to restore IL-1ß stimulation of IL mRNA levels in PLC treated with INDO were measured by ELISA in conditioned medium after IL-1ß treatment. Our data demonstrate that IL-1ß significantly increases the endogenous production of PGE2, PGF2{alpha}, and PGI2 by PLC (Fig. 7Go). The IL-1ß induction of these PGs is abolished in the presence of INDO.



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  		Figure 7. Stimulation of PLC PG production by IL-1ß. PLC were cultured for 24 h without (control) or with IL-1ß (10 ng/ml). PGs (PGE2, PGF2{alpha}, and 6-keto PGF1{alpha}, the stable metabolite of PGI2 degradation) in the conditioned serum-free medium were measured by ELISA. Data are expressed as the fold increase compared with that of the 24-h control value. Control values are as follows: PGE2, 443 ± 155 pg/106 cells; PGF2{alpha}, 165 ± 56 pg/106 cells; and 6-keto PGF1{alpha}, 188 ± 44 pg/106 cells. Results are the mean ± SEM from three individual experiments.

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
The findings of this study show that although COX1 mRNA levels are not affected by IL-1ß treatment in Leydig progenitors, COX2 mRNA is induced by IL-1ß. This regulation of COX2 mRNA levels does not involve COX2 metabolites, as COX inhibitors do not modify this response. The data also indicate that IL-1ß is a potent inducer of the levels of mRNA for several cytokines (IL-1{alpha}, IL-1ß, and IL-6) in rat PLC. Furthermore, in the presence of COX inhibitors, IL-1ß stimulation of cytokine mRNA is impaired, implicating the COX2 pathway in this regulation. In progenitors, exogenous PGs alone either do not stimulate (IL-1{alpha} and IL-1ß) or moderately stimulate (IL-6) cytokine mRNA levels. In contrast, when the progenitors are treated with IL-1ß and INDO, exogenous PGs fully restore the level of cytokine mRNAs to that achieved in the absence of the COX inhibitor. Finally, in PLC treated with IL-1ß and INDO, PGF2{alpha} and PGE2 are the most potent PGs to induce IL-1{alpha} and IL-1ß mRNAs. Moreover, cPGI2 is the most effective prostanoid for selective induction of IL-6 mRNA. IL-1ß treatment significantly increases the endogenous production of the three PGs (PGE2, PGF2{alpha}, and PGI2) by progenitors.

COX2 expression is induced in specialized cell types and tissues, such as ovarian granulosa cells, macrophages, endothelium, and seminal vesicles, and is developmentally regulated (1). Factors that regulate COX2 expression are specific for both the tissue and the function affected; the effects of COX2 activity on individual biological processes are defined by their cellular context. For example, in human endothelial cells IL-1ß, lipopolysaccharide (LPS), or TNF increases COX2 mRNA levels (45). In comparison, in granulosa cells COX2 is induced by IL-1ß, but is also hormonally induced by FSH and LH (46, 47, 48). The data presented herein demonstrate that although PLC COX1 mRNA levels are not regulated by IL-1ß, the steady state levels of COX2 mRNA are induced by this cytokine. Whether this effect is due to an increased transcription or a stabilization of COX2 mRNA was not investigated in the present study. COX2 mRNA induction by IL-1ß in PLC is not changed by the presence of COX inhibitors, findings consistent with an inhibition of COX catalytic activity without changes in gene expression. Moreover, these results suggest that AA metabolites do not exert a feedback control on PLC COX2 expression as was proposed recently for macrophages (49).

COX activity was shown to be involved in the production of IL-6, but not IL-1, in rodent models of inflammation (32, 33, 50). INDO blocks IL-6 mRNA induction by IL-1ß in the immature rat ovary (34). In contrast, Syed et al. (51) found that INDO increased IL-6 production in 20-d-old rat Sertoli cells stimulated by IL-1{alpha}. As AA metabolites derived from the lipoxygenase pathway are likely to be responsible for the increased production of IL-6 in immature Sertoli cells, the effect of INDO may be due in part to an accumulation of AA (51). In Leydig cells obtained from immature and adult rats, IL-1ß is a potent inducer of cytokine expression (27, 28, 29, 30, 31). Our present data demonstrate that IL-1ß induces multiple cytokine (IL-1{alpha}, IL-1ß, and IL-6) production in an earlier stage of Leydig cell maturation (PLC). Furthermore, both INDO and the selective COX2 inhibitor, NS-398, partially abrogated this effect. As the results obtained with INDO and NS-398 were not statistically different, COX2, and not COX1, mediates IL-1ß induction of cytokine mRNAs in PLC. These results are consistent with a specific association between COX2 activity and activation of inflammation-associated genes (33, 52).

In other tissues the effect of PGE2 on the regulation of cytokine expression has been extensively studied. PGE2 has opposing effects regarding the particular cytokines evaluated. The addition of PGE2 decreases the TNF{alpha} and IL-12 production induced in murine peritoneal macrophages stimulated by LPS or zymosan, two strong activators of inflammation (53, 54, 55, 56). In contrast, PGE2 potentiates IL-6 release induced by LPS or IL-1ß in murine peritoneal macrophages or the immature rat ovary, respectively (34, 54). Furthermore, Portanova and colleagues (50) showed that in a rat model of inflammation, an injection of anti-PGE2 antibodies reduces serum IL-6 levels. PGI2 analogs also modulate cytokine production in vitro in a similar way (56, 57, 58). The data shown in the present study indicate that PGE2, cPGI2, and PGF2{alpha} (10 µM for 18 h) induce IL-6 mRNA in PLC without affecting the levels of IL-1{alpha} and IL-1ß mRNAs. Although the 6- to 8-fold-induction of IL-6 mRNA by the PGs is modest (~15%) compared with that after IL-1ß induction (24 h), these results are consistent with significant differences in PG signaling and transcriptional activation of distinct IL gene promoters. Whereas PGs themselves had either no or a modest effect, they fully restored the IL-1ß induction of the three-cytokine mRNAs in progenitors treated with IL-1ß and INDO. A significant enhancement of the effect of IL-1ß in the presence of INDO was observed for PGF2{alpha} (IL-1{alpha} and IL-1ß mRNA) and cPGI2 (IL-6) and was confirmed in the absence of INDO (data not shown). These results are consistent with data previously obtained in murine peritoneal macrophages. Actually, exogenous PGE2 has either a weak inhibitory or a stimulatory effect on the production of TNF{alpha} and IL-6, respectively, in untreated macrophages (32, 33, 54). However, when PGE2 is added to macrophages activated by LPS or activated cells derived from a murine model of inflammation, the effect on the cytokine production is potentiated (32, 33). Williams and Shacter (33) proposed that other signals that regulate responsiveness to PGE2 have to be temporally correlated with PGE2 release to regulate cytokine production in macrophages. Based on data herein provided, a proposed schema for the mechanistic role of COX2 in the IL-1ß regulation of IL mRNA in PLC is illustrated (Fig. 8Go). Furthermore, to confirm that the IL-1ß effect is mediated by PGs, these mediators were measured for the first time in serum-free conditioned medium samples obtained from Leydig progenitors. Our data indicate that multiple PGs (PGE2, PGF2{alpha}, and PGI2) are released by IL-1ß-treated progenitors. Although the release of PGE2 by adult rat Leydig cells cultured with a combination of hCG and IL-1ß has been reported previously, PGF2{alpha} and PGI2 production was not investigated (19).



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  		Figure 8. IL-1ß induction of COX2 is involved in the regulation of IL mRNA levels in progenitors. In PLC, IL-1ß induces COX2 as well as other signals. COX2 activity initiates the production of PGs. Together with other signals, PGs may significantly induce the steady state levels of IL-1{alpha}, IL-1ß, and IL-6 mRNAs.

 
In the present study PGF2{alpha} and PGE2 are the most active of the PGs tested to restore the transcription of IL-1{alpha} and IL-1ß mRNAs in progenitor cells treated with IL-1ß and INDO. In contrast, cPGI2 is more effective in increasing IL-6 mRNA levels under the same conditions. Such specificity suggests that in PLC the receptors and/or the signal pathway activated by PGF2{alpha} and PGE2 are not the same as those used by cPGI2. In addition, our data are consistent with ligand-specific differences in transcriptional activators at the level of the IL-1 and IL-6 gene promoters. Further studies will be required to better understand the molecular mechanisms used by PGs to differentially activate cytokines in PLC.

IL-1 and IL-6 are produced in rat as well as human testis under basal conditions by Sertoli and Leydig cells during their development or during inflammation (17, 18, 27, 29, 30, 31, 51, 59). IL-1 and IL-6 have differential effects in the testis. For example, IL-1 has been found to stimulate DNA synthesis in spermatogonia and preleptotene spermatocytes, whereas IL-6 exerts the opposite effect (60, 61). The present report suggests that COX2 mRNA is induced by IL-1ß in rat PLC. The data are consistent with a mechanistic role for COX2 in the IL-1ß regulation of cytokine mRNA levels in these progenitor cells (Fig. 8Go). The findings of the present study suggest that COX2 could regulate the balance of the different testicular ILs and that selective COX2 inhibitors could provide new therapeutic strategies to modulate normal and pathological testicular function.


   Acknowledgments
 
The authors express their appreciation for the expert primary cell preparations by L. R. Mitchell and the editorial assistance of J. E. Schweis.


   Footnotes
 
This work was supported by NIH Grant R01-HD-39024 (to P.L.M.). Access to the Cell Culture Core Facility of The Population Council was provided by NICHD/NIH support through a cooperative agreement (U54-HD-13541) as part of the Specialized Cooperative Centers Program in Reproduction Research.

Abbreviations: AA, Arachidonic acid; COX, cyclooxygenase; cPGI2, carbaprostacyclin; CT, cycle number at which fluorescence exceeds threshold; DMSO, dimethylsulfoxide; 3ß-HSD, 3ß-hydroxysteroid dehydrogenase; INDO, indomethacin; LPS, lipopolysaccharide; PG, prostaglandin; PLC, progenitor Leydig cells; StAR, steroidogenic acute regulatory protein.

Received April 17, 2002.

Accepted for publication May 28, 2002.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Smith WL, DeWitt DL, Garavito RM 2000 Cyclooxygenases: structural, cellular, and molecular biology. Annu Rev Biochem 69:145–182[CrossRef][Medline]
  2. Smith WL, Langenbach R 2001 Why there are two cyclooxygenase isozymes. J Clin Invest 107:1491–1495[Medline]
  3. Futaki N, Takahashi S, Yokoyama M, Arai I, Higuchi S, Otomo S 1994 NS-398, a new anti-inflammatory agent, selectively inhibits prostaglandin G/H synthase/cyclooxygenase (COX-2) activity in vitro. Prostaglandins 47:55–59[CrossRef][Medline]
  4. Ouellet M, Percival MD 1995 Effect of inhibitor time-dependency on selectivity towards cyclooxygenase isoforms. Biochem J 306:247–251
  5. Lin T 1985 The role of calcium/phospholipid-dependent protein kinase in Leydig cell steroidogenesis. Endocrinology 117:119–126[Abstract/Free Full Text]
  6. Didolkar AK, Sundaram K 1987 Arachidonic acid is involved in the regulation of hCG induced steroidogenesis in rat Leydig cells. Life Sci 41:471–477[CrossRef][Medline]
  7. Abayasekara DR, Band AM, Cooke BA 1990 Evidence for the involvement of phospholipase A2 in the regulation of luteinizing hormone-stimulated steroidogenesis in rat testis Leydig cells. Mol Cell Endocrinol 70:147–153[CrossRef][Medline]
  8. Romanelli F, Valenca M, Conte D, Isidori A, Negro-Vilar A 1995 Arachidonic acid and its metabolites effects on testosterone production by rat Leydig cells. J Endocrinol Invest 18:186–193[Medline]
  9. Marinero MJ, Colas B, Prieto JC, Lopez-Ruiz MP 1996 Different sites of action of arachidonic acid on steroidogenesis in rat Leydig cells. Mol Cell Endocrinol 118:193–200[CrossRef][Medline]
  10. Mele PG, Dada LA, Paz C, Neuman I, Cymeryng CB, Mendez CF, Finkielstein CV, Cornejo Maciel F, Podesta EJ 1997 Involvement of arachidonic acid and the lipoxygenase pathway in mediating luteinizing hormone-induced testosterone synthesis in rat Leydig cells. Endocr Res 23:15–26[Medline]
  11. Moraga PF, Llanos MN, Ronco AM 1997 Arachidonic acid release from rat Leydig cells depends on the presence of luteinizing hormone/human chorionic gonadotrophin receptors. J Endocrinol 154:201–209[Abstract/Free Full Text]
  12. Wang X, Walsh LP, Reinhart AJ, Stocco DM 2000 The role of arachidonic acid in steroidogenesis and steroidogenic acute regulatory (StAR) gene and protein expression. J Biol Chem 275:20204–20209[Abstract/Free Full Text]
  13. Dix CJ, Habberfield AD, Sullivan MH, Cooke BA 1984 Inhibition of steroid production in Leydig cells by non-steroidal anti-inflammatory and related compounds: evidence for the involvement of lipoxygenase products in steroidogenesis. Biochem J 219:529–537[Medline]
  14. Conte D, Questino P, Fillo S, Nordio M, Isidori A, Romanelli F 1993 Endothelin stimulates testosterone secretion by rat Leydig cells. J Endocrinol 136:R1–R4
  15. Romanelli F, Fillo S, Isidori A, Conte D 1997 Stimulatory action of endothelin-1 on rat Leydig cells: involvement of endothelin-A subtype receptor and phospholipase A2-arachidonate metabolism system. Life Sci 61:557–566[CrossRef][Medline]
  16. Romanelli F, Fillo S, Isidori A, Conte D 1997 Pituitary adenylate cyclase-activating polypeptide regulates rat Leydig cell function in vitro. Neuropeptides 31:311–317[CrossRef][Medline]
  17. Khan S, Soder O, Syed V, Gustafsson K, Lindh M, Ritzen EM 1987 The rat testis produces large amounts of an interleukin-1-like factor. Int J Androl 14:494–503
  18. Cudicini C, Lejeune H, Gomez E, Bosmans E, Ballet F, Saez J, Jegou B 1997 Human Leydig cells and Sertoli cells are producers of interleukins-1 and -6. J Clin Endocrinol Metab 82:1426–1433[Abstract/Free Full Text]
  19. Calkins JH, Sigel MM, Nankin HR, Lin T 1988 Interleukin-1 inhibits Leydig cell steroidogenesis in primary culture. Endocrinology 123:1605–1610[Abstract/Free Full Text]
  20. Hales DB, Diemer T, Hales KH 1999 Role of cytokines in testicular function. Endocrine 10:201–217[Medline]
  21. Khan S, Khan S, Dorrington J 1992 Interleukin-1 stimulates deoxyribonucleic acid synthesis in immature rat Leydig cells in vitro. Endocrinology 131:1853–1857[Abstract/Free Full Text]
  22. Verhoeven G, Calleau J, Damme J, Billiau A 1988 Interleukin-1 stimulates steroidogenesis in cultured rat Leydig cells. Mol Cell Endocrinol 57:51–60[CrossRef][Medline]
  23. Okuda Y, Morris PL 1994 Identification of interleukin-6 receptor (IL-6R) mRNA in isolated Sertoli and Leydig cells: regulation by gonadotropin and interleukins in vitro. Endocrine 2:1163–1168
  24. Gaytan F, Bellido C, Morales C, Reymundo C, Aguilar E, van Rooijen N 1994 Selective depletion of testicular macrophages and prevention of Leydig cell repopulation after treatment with ethylene dimethane sulfonate in rats. J Reprod Fertil 101:175–182[Abstract/Free Full Text]
  25. Hales DB 1996 Leydig cell-macrophage interactions: an overview. In: Payne AH, Hardy MP, Russell LD, eds. The Leydig cell. Vienna: Cache River Press; 451–466
  26. Mendis-Handagama SM, Ariyaratne HB 2001 Differentiation of the adult Leydig cell population in the postnatal testis. Biol Reprod 65:660–671[Abstract/Free Full Text]
  27. Wang D, Nagpal ML, Calkins JH, Chang W, Sigel MM, Lin T 1991 Interleukin-1ß induces interleukin-1{alpha} messenger ribonucleic acid expression in primary cultures of Leydig cells. Endocrinology 129:2862–2866[Abstract/Free Full Text]
  28. Lin T, Wang D, Nagpal M 1993 Human chorionic gonadotropin induces interleukin-1 gene expression in rat Leydig cells in vivo. Mol Cell Endocrinol 95:139–145[CrossRef][Medline]
  29. Boockfor F, Wang D, Lin T, Nagpal M, Spangelo B 1994 Interleukin-6 secretion from rat Leydig cells in culture. Endocrinology 134:2150–2155[Abstract/Free Full Text]
  30. Okuda Y, Sun X-R, Morris PL 1994 Interleukin-6 (IL-6) mRNAs expressed in Leydig and Sertoli cells are regulated by cytokines, gonadotropins and neuropeptides. Endocrine 2:617–624
  31. Okuda Y, Bardin CW, Hodgskin LR, Morris PL 1995 Interleukins-1{alpha} and -1ß regulate interleukin-6 expression in Leydig and Sertoli cells. Recent Prog Horm Res 50:367–372
  32. Hinson RM, Williams JA, Shacter E 1996 Elevated interleukin 6 is induced by prostaglandin E2 in a murine model of inflammation: possible role of cyclooxygenase-2. Proc Natl Acad Sci USA 93:4885–4890[Abstract/Free Full Text]
  33. Williams JA, Shacter E 1997 Regulation of macrophage cytokine production by prostaglandin E2. Distinct roles of cyclooxygenase-1 and -2. J Biol Chem 272:25693–25699[Abstract/Free Full Text]
  34. Chung KW, Ando M, Adashi EY 2000 Periovulatory and interleukin (IL)-1-dependent regulation of IL-6 in the immature rat ovary: a specific IL-1 receptor-mediated eicosanoid-dependent effect. J Soc Gynecol Invest 7:301–308[CrossRef][Medline]
  35. Kanzaki M, Morris PL 1998 Lactogenic hormone-inducible phosphorylation and {gamma}-activated site-binding activities of Stat5b in primary rat Leydig cells and MA-10 mouse Leydig tumor cells. Endocrinology 139:1872–1882[Abstract/Free Full Text]
  36. Kanzaki M, Morris PL 1999 Growth hormone regulates steroidogenic acute regulatory protein expression and steroidogenesis in Leydig cell progenitors. Endocrinology 140:1681–1686[Abstract/Free Full Text]
  37. Wang DL, Nagpal ML, Calkins JH, Chang WW, Sigel MM, Lin T 1991 Interleukin-1ß induces interleukin-1{alpha} messenger ribonucleic acid expression in primary cultures of Leydig cells. Endocrinology 129:2862–2866
  38. Tatsumi N, Fujisawa M, Kanzaki M, Okuda Y, Okada H, Arakawa S, Kamidono S 1997 Nitric oxide production by cultured rat Leydig cells. Endocrinology 138:994–998[Abstract/Free Full Text]
  39. Monteleone G, Parrello T, Monteleone I, Tammaro S, Luzza F, Pallone F 1999 Interferon-{gamma} (IFN-{gamma}) and prostaglandin E2 (PGE2) regulate differently IL-12 production in human intestinal lamina propria mononuclear cells (LPMC). Clin Exp Immunol 117:469–475[CrossRef][Medline]
  40. Wu CY, Wang K, McDyer JF, Seder RA 1998 Prostaglandin E2 and dexamethasone inhibit IL-12 receptor expression and IL-12 responsiveness. J Immunol 161:2723–2730[Abstract/Free Full Text]
  41. Elvin JA, Yan C, Matzuk MM 2000 Growth differentiation factor-9 stimulates progesterone synthesis in granulosa cells via a prostaglandin E2/EP2 receptor pathway. Proc Natl Acad Sci USA 97:10288–10293[Abstract/Free Full Text]
  42. Behrman HR, Kodaman PH, Preston SL, Gao S 2001 Oxidative stress and the ovary. J Soc Gynecol Invest 8:S40–S42
  43. Kodaman PH, Behrman HR 2001 Endocrine-regulated and protein kinase C-dependent generation of superoxide by rat preovulatory follicles. Endocrinology 142:687–693[Abstract/Free Full Text]
  44. Blanco JC, Contursi C, Salkowski CA, DeWitt DL, Ozato K, Vogel SN 2000 Interferon regulatory factor (IRF)-1 and IRF-2 regulate interferon {gamma}-dependent cyclooxygenase 2 expression. J Exp Med 191:2131–2144[Abstract/Free Full Text]
  45. Jones DA, Carlton DP, McIntyre TM, Zimmerman GA, Prescott SM 1993 Molecular cloning of human prostaglandin endoperoxide synthase type II and demonstration of expression in response to cytokines. J Biol Chem 268:9049–9054[Abstract/Free Full Text]
  46. Sirois J, Simmons DL, Richards JS 1992 Hormonal regulation of messenger ribonucleic acid encoding a novel isoform of prostaglandin endoperoxide H synthase in rat preovulatory follicles. Induction in vivo and in vitro. J Biol Chem 267:11586–11592[Abstract/Free Full Text]
  47. Sirois J, Richards JS 1992 Purification and characterization of a novel, distinct isoform of prostaglandin endoperoxide synthase induced by human chorionic gonadotropin in granulosa cells of rat preovulatory follicles. J Biol Chem 267:6382–6388[Abstract/Free Full Text]
  48. Narko K, Ritvos O, Ristimaki A 1997 Induction of cyclooxygenase-2 and prostaglandin F2{alpha} receptor expression by interleukin-1ß in cultured human granulosa-luteal cells. Endocrinology 138:3638–3644[Abstract/Free Full Text]
  49. Inoue H, Tanabe T, Umesono K 2000 Feedback control of cyclooxygenase-2 expression through PPAR{gamma}. J Biol Chem 275:28028–28032[Abstract/Free Full Text]
  50. Portanova JP, Zhang Y, Anderson GD, Hauser SD, Masferrer JL, Seibert K, Gregory SA, Isakson PC 1996 Selective neutralization of prostaglandin E2 blocks inflammation, hyperalgesia, and interleukin 6 production in vivo. J Exp Med 184:883–891[Abstract/Free Full Text]
  51. Syed V, Stephan J-P, Gerard N, Legrand A, Parvinen M, Bardin CW, Jegou B 1995 Residual bodies activate Sertoli cell interleukin-1{alpha} (IL-1{alpha}) release, which triggers IL-6 production by an autocrine mechanism, through the lipoxygenase pathway. Endocrinology 136:3070–3078[Abstract]
  52. Mertz PM, DeWitt DL, Stetler-Stevenson WG, Wahl LM 1994 Interleukin 10 suppression of monocyte prostaglandin H synthase-2. Mechanism of inhibition of prostaglandin-dependent matrix metalloproteinase production. J Biol Chem 269:21322–21329[Abstract/Free Full Text]
  53. Kunkel SL, Spengler M, May MA, Spengler R, Larrick J, Remick D 1988 Prostaglandin E2 regulates macrophage-derived tumor necrosis factor gene expression. J Biol Chem 263:5380–5384[Abstract/Free Full Text]
  54. Yamane H, Sugimoto Y, Tanaka S, Ichikawa A 2000 Prostaglandin E2 receptors, EP2 and EP4, differentially modulate TNF-{alpha} and IL-6 production induced by lipopolysaccharide in mouse peritoneal neutrophils. Biochem Biophys Res Commun 278:224–228[CrossRef][Medline]
  55. Ikegami R, Sugimoto Y, Segi E, Katsuyama M, Karahashi H, Amano F, Maruyama T, Yamane H, Tsuchiya S, Ichikawa A 2001 The expression of prostaglandin E receptors EP2 and EP4 and their different regulation by lipopolysaccharide in C3H/HeN peritoneal macrophages. J Immunol 166:4689–4696[Abstract/Free Full Text]
  56. Shinomiya S, Naraba H, Ueno A, Utsunomiya I, Maruyama T, Ohuchida S, Ushikubi F, Yuki K, Narumiya S, Sugimoto Y, Ichikawa A, Oh-ishi S 2001 Regulation of TNF{alpha} and interleukin-10 production by prostaglandins I2 and E2: studies with prostaglandin receptor-deficient mice and prostaglandin E-receptor subtype-selective synthetic agonists. Biochem Pharmacol 61:1153–1160[CrossRef][Medline]
  57. Marcinkiewicz J 1991 In vitro cytokine release by activated murine peritoneal macrophages: role of prostaglandins in the differential regulation of tumor necrosis factor {alpha}, interleukin 1, and interleukin 6. Cytokine 3:327–332[CrossRef][Medline]
  58. Holladay CS, Wright RM, Spangelo BL 1993 Arachidonic acid stimulates interleukin-6 release from rat peritoneal macrophages in vitro: evidence for a prostacyclin-dependent mechanism. Prostaglandins Leukot Essent Fatty Acids 49:915–922[CrossRef][Medline]
  59. Syed V, Gerard N, Kaipia A, Bardin CW, Parvinen M, Jegou B 1993 Identification, ontogeny, and regulation of an interleukin-6-like factor in the rat seminiferous tubule. Endocrinology 132:293–299[Abstract/Free Full Text]
  60. Parvinen M, Soder O, Mali P, Froysa B, Ritzen EM 1991 In vitro stimulation of stage-specific deoxyribonucleic acid synthesis in rat seminiferous tubule segments by interleukin-1{alpha}. Endocrinology 129:1614–1620[Abstract/Free Full Text]
  61. Hakovirta H, Syed V, Jegou B, Parvinen M 1995 Function of interleukin-6 as an inhibitor of meiotic DNA synthesis in the rat seminiferous epithelium. Mol Cell Endocrinol 108:193–198[CrossRef][Medline]



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