The development of endometriosis is dependent on the presence of dendritic cells in mice

Abstract

OBJECTIVE: Endometriosis affects 10-15% of women of reproductive age and is associated with pelvic pain and infertility. Recently, we have shown that dendritic cells (DC) supplementation led to the enhancement of endometriosis lesion growth and of intra-lesion angiogenesis. In this study, we investigated whether the development of endometriosis is dependent on the presence of endogenous DC.DESIGN: Prospective study using a surgical model of endometriosis in mice.MATERIALS AND METHODS: Surgical induction of endometriosis was performed in 8-10 week old female mice. Briefly, under anesthesia, a midline laparotomy was performed, uterine horns were removed, and 2-mm biopsy punch samples were sutured to the peritoneal wall. After 8 days, mice were killed, their abdomens were opened through the same incision and lesions were measured in two perpendicular diameters (D1 and D2) and the cross-sectional lesion area calculated using the formula D1xD2xπ/4. Single cell suspensions were analyzed by flow cytometry. In order to ablate DC, we utilized CD11c-DTR/GFP transgenic mice (C57Bl/6 background), in which DC can be ablated in vivo. Administration of diphtheria toxin (DT) into the transgenic mice that express the primate DT receptor (DTR), resulted in depletion of CD11c+DC. Endometriosis was induced in 10 CD11c-DTR/GFP transgenic mice and in 10 C57Bl/6 control mice. The mice were allocated to 4 groups (n=5 mice per group): I: C57Bl/6 treated with vehicle; II: C57Bl/6 treated with DT; III: CD11c-DTR/GFP transgenic mice treated with DT; IV: CD11c-DTR/GFP transgenic mice treated with vehicle. On day 0, endometriosis was induced. On days 2, 5, and 9, DT or vehicle was administered. All mice were sacrificed on day 10, the lesions were measured, and surgically removed from the abdominal cavity.RESULTS: In CD11c-DTR/GFP transgenic mice that were treated with DT (Group III) the endometriotic lesions were significantly smaller than that of all the other groups (ANOVA) (i.e. Group I: 5.25±1.18 mm2; Group II: 4.73±1.11 mm2; Group III: 1.09 ± 0.38 mm2; Group IV: 5.12±1.09 mm2, p<0.001). Single cell suspensions of endometriosis lesions were analyzed by flow cytometry, showing a near complete ablation of DC in Group III while no ablation was observed in the other 3 groups of mice.CONCLUSIONS: Our results indicate that endometriosis is dependent on the infiltrating DC population. Therapies designed to inhibit DC infiltration could target endometriosis in the future. This possibility warrants further studies. OBJECTIVE: Endometriosis affects 10-15% of women of reproductive age and is associated with pelvic pain and infertility. Recently, we have shown that dendritic cells (DC) supplementation led to the enhancement of endometriosis lesion growth and of intra-lesion angiogenesis. In this study, we investigated whether the development of endometriosis is dependent on the presence of endogenous DC. DESIGN: Prospective study using a surgical model of endometriosis in mice. MATERIALS AND METHODS: Surgical induction of endometriosis was performed in 8-10 week old female mice. Briefly, under anesthesia, a midline laparotomy was performed, uterine horns were removed, and 2-mm biopsy punch samples were sutured to the peritoneal wall. After 8 days, mice were killed, their abdomens were opened through the same incision and lesions were measured in two perpendicular diameters (D1 and D2) and the cross-sectional lesion area calculated using the formula D1xD2xπ/4. Single cell suspensions were analyzed by flow cytometry. In order to ablate DC, we utilized CD11c-DTR/GFP transgenic mice (C57Bl/6 background), in which DC can be ablated in vivo. Administration of diphtheria toxin (DT) into the transgenic mice that express the primate DT receptor (DTR), resulted in depletion of CD11c+DC. Endometriosis was induced in 10 CD11c-DTR/GFP transgenic mice and in 10 C57Bl/6 control mice. The mice were allocated to 4 groups (n=5 mice per group): I: C57Bl/6 treated with vehicle; II: C57Bl/6 treated with DT; III: CD11c-DTR/GFP transgenic mice treated with DT; IV: CD11c-DTR/GFP transgenic mice treated with vehicle. On day 0, endometriosis was induced. On days 2, 5, and 9, DT or vehicle was administered. All mice were sacrificed on day 10, the lesions were measured, and surgically removed from the abdominal cavity. RESULTS: In CD11c-DTR/GFP transgenic mice that were treated with DT (Group III) the endometriotic lesions were significantly smaller than that of all the other groups (ANOVA) (i.e. Group I: 5.25±1.18 mm2; Group II: 4.73±1.11 mm2; Group III: 1.09 ± 0.38 mm2; Group IV: 5.12±1.09 mm2, p<0.001). Single cell suspensions of endometriosis lesions were analyzed by flow cytometry, showing a near complete ablation of DC in Group III while no ablation was observed in the other 3 groups of mice. CONCLUSIONS: Our results indicate that endometriosis is dependent on the infiltrating DC population. Therapies designed to inhibit DC infiltration could target endometriosis in the future. This possibility warrants further studies.