SAT381 Effect of Obesity on Androgen-induced Splenic Dysregulation in Polycystic Ovary Syndrome

Disclosure: S. Rezq: None. J. Basnet: None. A.M. Huffman: None. L.L. Yanes Cardozo: None. D.G. Romero: None. Background: Polycystic ovary syndrome (PCOS) is characterized by ovarian dysfunction and hyperandrogenism. Women with PCOS exhibit low-grade systemic inflammation, obesity, and immune dysregulation. The spleen plays an important role in immune function and physiological inflammation regulation. Androgens and obesity negatively impact splenic structure and function. However, the effect of androgens on spleen architecture and function and its modulation by obesogenic diet is unknown in PCOS. Using a well-established PCOS model of hyperandrogenemia we aim to test the hypothesis that androgens cause splenic dysregulations that are exacerbated by obesity. Methods: Three-week-old female mice were treated with the androgen dihydrotestosterone (DHT, 8 mg, s.c) or vehicle. Animals were fed a high-fat diet (HFD; 60% kcal fat) or a low-fat diet (LFD; 10% kcal fat) for 90 days (n=6-8/group). Body composition (EchoMRI) and spleen weight were assessed. Splenic mRNA or protein expression of multiple immune cells/regulatory markers such as chemokines ligands Cxcl12 and Lymphotoxin B (Ltb), and their corresponding receptors C-X-C chemokine receptor type 4 (CXCR4) and Ltb receptor (LTBR), as well as the chemokine monocyte chemoattractant protein-1 (MCP-1), proliferation markers Csf1, Csf2, and Csf3, the adhesion molecule Vcam1, and extracellular matrix (ECM) remodeling marker Coch were assessed by RT-qPCR or Western blot. Additionally, splenic androgen receptor (AR) protein expression was measured by Western blot, while the inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor (TNF-α) were detected by ELISA. Results: DHT significantly (p<0.05) increased fat mass (6.2 ± 0.5 vs. 3.4 ± 0.3 g) and spleen weight (11.9 ± 1.6 vs. 4.9 ± 0.22 g) in LFD-fed mice, which was exacerbated by HFD. DHT-mediated splenomegaly was associated with a significant (p<0.05) decrease in the expression of AR (90%), the chemokine Cxcl12 (70-80%), the proliferation markers Csf1 and Csf2 (65-66%), and the ECM marker Coch (70%) in mice that were fed on both diets. PCOS mice had significantly (p<0.05) higher CXCR4 (4.4-4.7-fold) and LTBR (5.7-7.6-fold) expression, independent of diet. Interestingly, only the HFD-fed PCOS mice had significantly (p<0.05) lower splenic Vcam1 (76%), IL-6 (25%), and TNF-α (4.6 ± 0.2 vs. 5.6 ± 0.2 pg/μg protein) levels, while they also had higher MCP-1 protein levels (2-fold, p<0.05). Conclusion and significance: Our data show that androgens cause splenic structural and molecular alterations that are modulated by obesity. These findings could explain PCOS-associated immune dysregulation that is more predominant in obese women with PCOS. The study highlights the spleen as a novel key target organ of androgen-mediated pathology in PCOS. Furthermore, our study suggests that weight loss could potentially attenuate androgen-associated splenic derangements in PCOS. Presentation Date: Saturday, June 17, 2023