ß-Adrenergic Receptors Modulate COX2 Expression in Macrophages: Possible Implications in Testicular Inflammatory Events

Presentation Number: THR-127
Date of Presentation: March 5th, 2015

Maria Eugenia Matzkin*1, Ricardo S Calandra2 and Monica Beatriz Frungieri1
1Instituto de Biología y Medicina Experimental (IBYME-CONICET), Caba, Argentina, 2Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina

Abstract

We have previously described the presence of catecholaminergic neuronal elements (CNE) in testes of men suffering from idiopathic infertility (1). Contrary to that observed in the normal human testis, increased numbers of testicular MAC (2,3) and CNE (1), as well as the expression of cyclooxygenase 2 (COX2) (4), key enzyme in prostaglandin synthesis, are limited to infertility status. Also, a close anatomical proximity between CNE and other cell populations of the testis such as Leydig cells (LC) and macrophages (MAC) has been reported, therefore suggesting a role for catecholamines in MAC or LC function. In this context, we have found that testosterone production in Syrian hamster LC is regulated by epinephrine (E) and norepinephrine (NE) via α1 and β-adrenergic receptors (AR) (5). In this study, we addressed a possible effect of E/NE in COX2 expression in MAC. Laser capture microdissection of CD68-positive testicular MAC in infertile testes, followed by RT-PCR allowed to determine the expression of β-AR. Since no functional assays can be performed in testicular biopsy tissues, two alternative experimental models were used: non-testicular human MAC (THP1 cell line) and testicular MAC purified from adult Syrian hamsters. Both MAC models expressed β1, β2 and β3-AR. After 1 h incubations, COX2 expression (determined by qPCR) in THP1 MAC was up-regulated by 1mM E, NE, Isoproterenol (I: β-AR agonist) and Salbutamol (S: β2-AR agonist). In addition, stimulatory effects exerted by E, NE, I and S were reverted in the presence of 1mM Propranolol (P: β1-β2-AR antagonist) (qPCR COX2/GAPDH, Control: 1.0±0.6, E: 6.9±0.5*, E+P: 0.9±0.6, NE: 3.1±0.7*, NE+P: 1.5±0.7, I: 3.0±0.9*, I+P: 1.3±0.6, S: 1.7±0.4+0.6*, S+P: 0.3±0.3, P: 0.9±0.6; X±SEM *P<0.05). In contrast, the addition of 10 nM Atenololol (A: β1-AR antagonist) did not affect COX2 expression (Control: 1.0±0.2, E: 3.1±1.0*, E+A: 2.3±0.4*, NE: 2.4±0.6*, NE+A: 2.9±0.1*, I: 4.6±1.4*, I+A: 7.9±1.2*, S: 2.3±0.8*, S+A: 2.2±0.8*, A: 1.0±0.1; X±SEM *P<0.05)

When testicular MAC purified from adult hamsters were assayed, COX2 expression was induced in the presence of 1mM E (Control: 1.0±0.2 vs. E: 3.5±0.0*; X±SEM *P<0.05), NE (Control: 1.0±0.2 vs. NE: 5.6±0.8*; X±SEM *P<0.05), I (Control: 1.0±0.3 vs. I: 10.8±0.9*; X±SEM *P<0.05) and S (Control: 1.0±0.2 vs. S: 2.5±0.3*; X±SEM *P<0.05).

In summary, we hereby describe the expression of β-AR in testicular MAC from biopsies of infertile men. Our data indicates that E/NE up-regulation of COX2 expression in MAC is mediated, most likely, by β2-AR, although a β3-AR-mediated effect cannot be ruled out at this point. Overall, these results suggest the importance of E/NE as modulators of inflammatory events in the testis.

 

Nothing to Disclose: MEM, RSC, MBF