Interleukin-22 secreted by ectopic endometrial stromal cells and natural killer cells promotes the recruitment of macrophages through promoting CCL2 secretion.

PROBLEM: During endometriosis, there is an increase in the number of dysfunctional macrophages; however, the mechanisms underlying macrophage recruitment are not well understood. The aim of the present study was to determine the role of natural killer (NK) cell-mediated secretion of chemokine (C-C motif) ligand 2 (CCL2) from endometrial stromal cells (ESCs) in the recruitment of macrophages. METHOD OF STUDY: Normal ESCs (nESC) and ectopic ESCs (eESCs) were separately co-cultured with NK cells for a macrophage chemotaxis assay, and the number of chemotactic macrophages was counted. The expression of interleukin-22 (IL-22) and IL-22 receptors was detected by ELISA and flow cytometry, respectively. eESCs were treated with 0.01, 0.1, and 1 ng/mL recombinant human IL-22 (rhIL-22) to determine the most effective concentration for stimulating CCL2 production. Following treatment with 1 ng/mL rhIL-22, secretion of CCL2 was detected from both the eESC monoculture and the eESC/NK co-culture. RESULTS: Compared with the eESC monoculture, the eESC/NK co-culture recruited a significantly higher number of chemotactic macrophages. There was also an increase in the levels of IL-22 and CCL2 secreted when eESCs were co-cultured compared with the monoculture. Treatment with rhIL-22 resulted in an increase in the levels of CCL2 secreted by eESCs, and the IL-22-induced CCL2 secretion was reversed by the IL-22 antagonist, αIL-22. Increased expression of IL-22 resulted in an increase in the number of chemotactic macrophages, but was reversed by αIL-22 and CCL2 antagonist (αCCL2). CONCLUSION: Interleukin-22 and CCL2 secretion by eESCs stimulated by NK cells contributes to the induction of macrophage recruitment and is thus implicated in the development of endometriosis.

CXCL16/CXCR6 interaction promotes endometrial decidualization via the PI3K/AKT pathway.

Decidualization renders the endometrium transiently receptive to an implanting blastocyst although the underlying mechanisms remain incompletely understood. The aim of this study was to determine the role of chemokine CXCL16 and its receptor CXCR6 in the decidualization during pregnancy. Here, the expression of CXCL16 was investigated in endometrial tissues, decidua and placenta in this study. Compared with endometrial tissue, protein expression of CXCL16 was significantly higher in tissues from the fertile control samples, especially in villus. Meanwhile, the primary trophoblast cells and decidual stromal cells (DSCs) secreted more CXCL16 and expressed higher CXCR6 compared to endometrial stromal cells (ESCs) in vitro. Stimulation with the inducer of decidualization (8-bromoadenosine 3',5'-cyclic with medroxyprogesterone acetate, 8-Br-cAMP plus MPA) significantly upregulated the expression of CXCL16 and CXCR6 in ESCs in vitro. After treatment with exogenous recombinant human CXCL16 (rhCXCL16) or trophoblast-secreted CXLC16, decidualised ESCs showed a significant decidual response, mainly characterised by increased prolactin (PRL) secretion. Simultaneously, PI3K/PDK1/AKT/Cyclin D1 pathway in decidualised ESCs were activated by rhCXCL16, and AKT inhibitor GS 690693 abolished the PRL secretion of ESCs that was triggered by rhCXCL16. Finally, the impaired CXCL16/CXCR6 expression could be observed at the maternal-foetal interface from patients who have experienced spontaneous abortion. This study suggests that the CXCL16/CXCR6 axis contributes to the progression of ESC decidualization by activating PI3K/PDK1/AKT/Cyclin D1 pathway. It unveils a new paradigm at the maternal-foetal interface in which CXCL16 is an initiator for the molecular crosstalk that enhances decidualization of ESCs.

Phenolic glycosides from Ficus tikoua and their cytotoxic activities.

Four new phenolic glycosides, named 2-ethylene-3,5,6-trimethyl-4-phenol-1-O-ß-d-xylopyranosyl-(1→6)-ß-d-glucopyranoside (1), 3-methoxy-4-O-ß-d-apiofuranosyl-(1→2)-ß-d-glucopyranosylpropiophenone (2), 3-hydroxy-1-(4-O-ß-d-glucopyranosyl-3-methoxyphenyl)propan-1-one (3) and 4-hydroxy-3,5-bis(3'-methyl-2-butenyl)benzoic acid-O-ß-d-glucopyranoside (4), were isolated from the ethanol extract of Ficus tikoua, together with six known compounds: 3,4,5-trimethoxyphenol-1-O-ß-d-apiofuranosyl-(1→6)-ß-d-glucopyranoside (5), 3,4,5-trimethoxyphenol-1-O-ß-d-glucopyranoside (6), 3-methoxy-4-O-ß-d-apiofuranosyl-(1→6)-ß-d-glucopyranosylpropiophenone (7), baihuaqianhuoside (8), 3,5-dimethoxy-4-hydroxybenzoic acid-O-ß-d-glucopyranoside (9) and 2-methoxy-4-allylphenyl-1-O-ß-d-apiofuranosyl-(1→6)-ß-d-glucopyranoside (10). The structures of the four new compounds were elucidated by chemical methods and MS and IR, as well as 1D and 2D NMR analyses. The cytotoxicities of the 10 compounds against HeLa, K562, HL60 and HepG2 cell lines were assessed.