(183) MACROPHAGE-DERIVED TLR9 ACTIVATION ON INFLAMMATION, VASCULAR AND ERECTILE DYSFUNCTION: PERSPECTIVES FOR TREATING COMPLICATIONS ASSOCIATED WITH OBESITY AND DIABETES

Abstract Introduction Obesity represents a significant risk factor for various ailments like type 2 diabetes and cardiovascular conditions, alongside complications such as sexual dysfunction, which is linked to inflammation even in the absence of cardiovascular problems. Recently our group described that inhibiting TNF-α production in macrophage-specific-TLR9-mutant mice subjected to a high-fat diet prevented sexual dysfunction, underscoring the involvement of macrophage-derived TLR9 activation on the etiology of obesity-induced ED. The augmented adipose tissue levels in obesity result in increased macrophage levels, indicating that modulation of the inflammatory response of these macrophages could serve as an alternative therapeutic approach for sexual dysfunction. Objective This investigation tested the hypothesis that TLR9 activation through the agonist ODN2395 will increase the pro-inflammatory cytokine profile in macrophages, and in turn, these cytokines negatively alter vascular reactivity and corpus cavernosum functionality in mice. Methods The cytokine profile secreted by macrophages was evaluated by culturing mouse bone marrow-derived macrophages (BMDM) incubated with 1uM of ODN2395. After 24 hours of incubation, the supernatant was collected for Elisa analysis. To address vascular and cavernosal reactivity, the pudendal artery and corpus cavernosum were harvested from C57BL/6 J mice and incubated with ODN2395, in the presence or the absence of BMDM. After 24 hours of incubation, dose–response curves were generated for acetylcholine and phenylephrine. Results Stimulation of BMDM with ODN2395 led to a dose-dependent increase in TNF-α, IL-6 and IL-10, with the highest concentration (1uM) elevating the expression of inflammatory proteins derived from macrophages. In the pudendal artery, there was an enhancement in the maximal contractile response to phenylephrine in the presence of ODN2395 (VHC 8.114 +/- 0.71 vs ODN 12.515 +/-1.228; Mφ 10.113 +/- 0.674 vs Mφ + ODN 13.983 +/- 0.916), while no impact was observed on vascular relaxation. Within the corpus cavernosum, there was a tendency towards an increased maximal contractile response to phenylephrine following incubation with ODN2395, yet no effect was noted on acetylcholine-induced relaxation. Incubation with BMDM did not affect pudendal artery or cavernosal reactivity. Conclusions These findings indicate that macrophage-derived TLR9 activation by ODN2395 induces cytokine release from macrophages, however, vascular and cavernosal reactivity were impaired by ODN2395 independent of macrophages, suggesting that tissue activation of TLR9 may also play a role in the pathophysiology of ED. Disclosure No.