Abnormal HCK/glutamine/autophagy axis promotes endometriosis development by impairing macrophage phagocytosis.

The presence of extensive infiltrated macrophages with impaired phagocytosis is widely recognised as a significant regulator for the development of endometriosis (EMs). Nevertheless, the metabolic characteristics and the fundamental mechanism of impaired macrophage phagocytosis are yet to be clarified. Here, we observe that there is the decreased expression of haematopoietic cellular kinase (HCK) in macrophage of peritoneal fluid from EMs patients, which might be attributed to high oestrogen and hypoxia condition. Of note, HCK deficiency resulted in impaired macrophage phagocytosis, and increased number and weight of ectopic lesions in vitro and in vivo. Mechanistically, this process was mediated via regulation of glutamine metabolism, and further upregulation of macrophage autophagy in a c-FOS/c-JUN dependent manner. Additionally, macrophages of EMs patients displayed insufficient HCK, excessive autophagy and phagocytosis dysfunction. In therapeutic studies, supplementation with glutamine-pre-treated macrophage or Bafilomycin A1 (an autophagy inhibitor)-pre-treated macrophage leads to the induction of macrophage phagocytosis and suppression of EMs development. This observation reveals that the aberrant HCK-glutamine-autophagy axis results in phagocytosis obstacle of macrophage and further increase the development risk of Ems. Additionally, it offers potential therapeutic approaches to prevent EMs, especially patients with insufficient HCK and macrophage phagocytosis dysfunction.

PrPC Promotes Endometriosis Progression by Reprogramming Cholesterol Metabolism and Estrogen Biosynthesis of Endometrial Stromal Cells through PPARα Pathway.

Endometriosis (EMs) is characterized as an estrogen-dependent disease. Whereas, the underlying mechanism for activated estrogen biosynthesis in EMs lesions is largely unknown. We analyzed cholesterol metabolism and estrogen biosynthesis condition of EMs lesions by biological information analysis of GEO datasets, and further verified both in vitro and in vivo by constructing EMs models with uterus fragments from donors of PRNP knockout mouse (Prnp-/-, KO119), Octapeptide repeat region of PRNP knockout mouse (KO120) and PRNP transgenic mouse (Tg20). We found that transcriptome of cholesterol metabolism and estrogen-converting enzymes were disturbed in EMs patients, and cellular cholesterol concentration and local estradiol level were substantially increased in EMs lesions, as well as the high level of prion (PrPC, encoded by PRNP). Notably, 17-ß estradiol stimulation significantly up-regulated PrPC expression in endometrial stromal cells (ESC) and PrPC promoted the proliferative, migratory and invasive abilities of ESC, and was further verified to accelerate EMs progression in mouse models. More importantly, PrPC promoted cholesterol accumulation and activated estrogen biosynthesis of ESC in a PPARα pathway-dependent manner. Taken together, this study suggests that PrPC-cholesterol metabolism/estrogen biosynthesis contributes to the progression of EMs by negatively regulating PPARα pathway, and could be potential therapeutic targets for EMs intervention.

Follistatin-like I promotes endometriosis by increasing proinflammatory factors and promoting angiogenesis.

Endometriosis (EMS) is a chronic benign inflammatory disease characterized by the growth of endometrial-like tissue in aberrant locations outside of the uterine cavity. Angiogenesis and abnormal immune responses are the fundamental requirements of endometriotic lesion survival in the peritoneal cavity. Follistatin-like I (FSTL1) is a secreted glycoprotein that exhibits varied expression levels in cardiovascular disease, cancer and arthritis. However, the role of FSTL1 in the development of EMS remains to be fully elucidated. Results of the present study demonstrated that the expression of FSTL1 was significantly increased in ectopic endometrial stromal cells (ESCs) and peritoneal fluid from patients with EMS, compared to the control group. Both conditions of hypoxia and estrogen treatment induced human ESCs to produce increased levels of FSTL1 and disco-interacting protein 2 homolog A (DIP2A). Furthermore, the expression levels of DIP2A, IL8 and IL1ß were increased in FSTL1 overexpressed HESCs. Additionally, FSTL1 treatment increased the proliferation of HUVECs in a dose-dependent manner in vitro and markedly increased the tube formation of HUVECs. Moreover, treatment with FSTL1 facilitated M1 polarization of macrophages, increased the secretion of proinflammatory factors and inhibited the expression of scavenger receptor CD36. Results of the present study suggested that the elevated expression of FSTL1 may play a key role in accelerating the development of EMS via enhancing the secretion of proinflammatory factors and promoting angiogenesis.

Estrogen-regulated CD200 inhibits macrophage phagocytosis in endometriosis.

OBJECTIVES: Endometriosis (EMS) is a benign disease that is related to estrogen, immune disorders and inflammation. The purpose of this research was to determine the expression of CD200 in EMS and to clarify its role in the pathogenesis of the disease. METHODS: The levels of serum CD200 in patients with and without EMS were determined by ELISA. Furthermore, the expression of CD200 in normal eutopic endometrium and ectopic endometrium was detected by immunohistochemistry and western blotting. The CD200 receptor (CD200R) in macrophages in peritoneal fluid (pMØ) obtained from controls and patients with EMS was examined by western blotting. CD200 expression in human endometrial stromal cells (HESCs) stimulated with 17ß-estradiol (E2) was measured by western blotting. Furthermore, macrophages were stimulated with different concentrations of CD200 and the effect on phagocytosis was analyzed. RESULTS: The plasma CD200 levels of patients with EMS was significantly increased compared with controls (P = 0.0173, 95%CI [18.75, 159.6]). Compared with normal eutopic endometrium, the expression of CD200 was significantly increased in ectopic endometrial tissues. The CD200R expression in pMØ obtained from patients with EMS was increased compared with the controls (P = 0.0244). CD200 expression in HESCs stimulated with E2 was up-regulated. As the levels of CD200 increased, macrophage phagocytosis in vitro gradually decreased. CONCLUSIONS: CD200 is an estrogen-induced molecule that impairs macrophage phagocytosis and may contribute to the immune escape of ectopic lesions in EMS.

Decidual stromal cells promote the differentiation of CD56bright CD16- NK cells by secreting IL-24 in early pregnancy.

PROBLEM: Decidual stromal cells (DSCs) are important origins of cytokines to modulate maternal-fetal immunotolerance and provide a feasible environment for embryo implantation and development. Interleukin (IL)-24 is a multifunctional cancer killing cytokine and a pleiotropic immunoregulator with complex potency according to tissue or cell types. Its role in establishment and maintenance of normal pregnancy is largely unknown. The aim of our study was to investigate the function and significance of IL-24 and its receptor in the coordination between DSCs and natural killer cells (NK) in early pregnancy. METHOD OF STUDY: The levels of IL-24 in DSC, endometrial stromal cell (ESC), peripheral blood NK cells (pNK), or decidual NK cells (dNK) culture supernatants were detected by enzyme-linked immunosorbent assay (ELISA), and the levels of IL-24 receptors were determined by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry assays. The effect of IL-24 on the functions of decidual NK cells was analyzed by flow cytometry assays in vitro. RESULTS: The concentration of IL-24 in culture supernatant of DSCs was significantly higher than that of ESCs. Both eNK (endometrial NK cells) and dNK highly expressed IL-24 receptors (IL-20R1 and IL-22R1), especially on CD56dim eNK. However, there were extremely low levels of IL-20R1 and IL-22R1 on pNK. Recombinant human IL-24 or DSCs-secreted IL-24 downregulated the levels of CD16, Granzyme B, perforin, and interferon (IFN)-γ and upregulated the levels of inhibitory receptors killer-cell immunoglobulin-like receptor (KIR)2DL1 and KIR3DL1, or immunotolerant or angiogenic cytokines (eg, transforming growth factor (TGF)-ß, IL-10, and IL-8), and elevated the percentage of CD56bright CD16- dNK in vitro. CONCLUSION: These data suggest that DSCs promote the differentiation of CD56bright CD16- NK with high levels of inhibitory receptors, immunotolerant, and angiogenic cytokines by secreting IL-24 during decidualization in early pregnancy.