Fractalkine/CX3CR1 is involved in the pathogenesis of endometriosis by regulating endometrial stromal cell proliferation and invasion

Fractalkine modulates pulmonary angiogenesis and tube formation by modulating CX3CR1 and growth factors in PVECs

This study aimed to investigate effects of pulmonary fractalkine (FKN/CX3CL1) on angiogenesis and tube formation. Tube forming capability of pulmonary vascular endothelial cells (PVECs) was evaluated. CCK-8 assay was used to evaluate proliferation of PVECs. RT-PCR assay was used to determine angiogenesis specific biomarkers. Western blot was applied to identify CX3CR1, Akt, phosphorylated Akt (p-Akt), Erk1/2, phosphorylated Erk1/2 (p-Erk1/2), vascular endothelial growth factor A (VEGFA), and inducible nitric oxide synthase (iNOS) expression. VEGF-A and platelet-derived growth factor (PDGF) levels were examined using ELISA. FKN was safe and triggered tube formation in PVECs. FKN significantly enhanced VEGF-A, PDGF, and iNOS gene transcription compared to the Control group (p < 0.05). CX3CR1 interfering (LV5-CX3CR1 shRNA) remarkably reduced CX3CR1 expression compared to those in LV5 blank group (p < 0.05). Ratios of p-Akt/Akt and p-Erk/Erk were significantly decreased in CX3CR1 shRNA-treated PVECs administered Akt inhibitor (or Erk inhibitor) and 10 ng/mL FKN compared to CX3CR1 shRNA-treated PVECs administered 10 ng/mL FKN (p < 0.05). FKN increased VEGF-A and iNOS expression through activating Akt/Erk pathway. FKN promoted VEGF-A/iNOS expression and triggered p-Akt/Akt and p-Erk/Erk pathway through modulating CX3CR1. FKN-treated macrophages enhanced activation of Akt/Erk pathway. FKN-treated macrophages enhanced PDGF and VEGF-1 expression in PVECs. FKN modulated pulmonary angiogenesis and tube formation through modulating CX3CR1 and growth factors and activating p-Akt/Akt and p-Erk/Erk signaling pathway.

Synergy between Th1 and Th2 responses during endometriosis: A review of current understanding

Endometriosis is widely perceived as an estrogen-dependent chronic disorder with infertility and pelvic pain. Although the etiology of endometriosis has remained elusive, many studies have proclaimed the relevance of immune system disorders with endometriosis. With the discovery that the dysregulation of multiple biological functions in endometriosis is caused by the aberrant differentiation of T helper cells, a shift towards Th2 immune response may account for the disease progression. This review attempts to present mechanisms of cytokines, chemokines, signal pathways, transcription factors and some other factors related with the derivation of Th1/Th2 immune response involved in the development of endometriosis. The current understanding of treatment approaches and potential therapeutic targets will also be outlined with brief discussion.

Knock-out of 5-lipoxygenase in overexpressing tumor cells-consequences on gene expression and cellular function

5-Lipoxygenase (5-LO), the central enzyme in the biosynthesis of leukotrienes, is frequently expressed in human solid malignancies even though the enzyme is not present in the corresponding healthy tissues. There is little knowledge on the consequences of this expression for the tumor cells regarding gene expression and cellular function. We established a knockout (KO) of 5-LO in different cancer cell lines (HCT-116, HT-29, U-2 OS) and studied the consequences on global gene expression using next generation sequencing. Furthermore, cell viability, proliferation, migration and multicellular tumor spheroid (MCTS) formation were studied in these cells. Our results show that 5-LO influences the gene expression and cancer cell function in a cell type-dependent manner. The enzyme affected genes involved in cell adhesion, extracellular matrix formation, G protein signaling and cytoskeleton organization. Furthermore, absence of 5-LO elevated TGFβ₂ expression in HCT-116 cells while MCP-1, fractalkine and platelet-derived growth factor expression was attenuated in U-2 OS cells suggesting that tumor cell-derived 5-LO shapes the tumor microenvironment. In line with the gene expression data, KO of 5-LO had an impact on cell proliferation, motility and MCTS formation. Interestingly, pharmacological inhibition of 5-LO only partly mimicked the KO suggesting that also noncanonical functions are involved.

The Role of Selected Chemokines in the Peritoneal Fluid of Women with Endometriosis—Participation in the Pathogenesis of the Disease

Endometriosis is a disorder characterized by the presence of endometrial tissue outside the uterine cavity, primarily into the peritoneal cavity. It is known as a complex, chronic inflammatory disease and it is strongly associated with immune dysregulation. Various soluble mediators of the immune and inflammatory responses, including chemokines, play an important role in these processes. The aim of the study was to understand the role of the chemokines MCP-1, MCP-2, MCP-3, MCP-4, MIP-1 α, MIP-1β, eotaxin 2, eotaxin 3, ENA-78, and fractalkine in the development of endometriosis through their assessment in the peritoneal fluid of women with endometriosis. The study group included 58 women with endometriosis who were diagnosed during laparoscopy and then confirmed by histopathology. In 15 women from the reference group, laparoscopic examination demonstrated a normal status of the pelvic organs without any evidence of endometriosis nor inflammation in the peritoneal cavity. The peritoneal fluid of women with endometriosis and of women from the reference group were examined. To determine the concentration of the studied chemokines, enzyme immunoassays for Luminex® platforms were used. In the peritoneal fluid of women with endometriosis, a statistically significant increase in the concentration of MIP-1β, eotaxin 2, eotaxin 3, ENA-78, and fractalkine and a decrease in the concentration of MCP-1, MCP-2, MCP-3, MCP-4, and MIP-1α were observed compared to the reference group. The concentration of these cytokines depended on the severity of the disease. Changes in the concentration of the studied chemokines in the peritoneal fluid of women with endometriosis suggest their participation in the pathogenesis of the disease. The differences in chemokines concentration observed in different stages of endometriosis may be associated with the presence of inflammation in the peritoneal cavity at each step of disease development.

Fractalkine enhances endometrial receptivity and activates iron transport towards trophoblast cells in an in vitro co-culture system of HEC-1A and JEG-3 cells

Endometrium receptivity and successful implantation require a complex network of regulatory factors whom production is strictly controlled especially at the implantation window. Many regulators like steroid hormones, prostaglandins, cytokines, extracellular matrix proteins and downstream cell signalling pathways are involved in the process of embryo-endometrium interaction. Our work reveals the effect of fractalkine (FKN), a unique chemokine on progesterone receptor, SOX-17 and NRF2 expressions in HEC-1A endometrial cell line. FKN activates fractalkine receptor signalling and the expression of SOX-17 through progesterone receptor in HEC-1A endometrial cells, and as a consequence it increases endometrial receptivity. Fractalkine also activates the NRF2-Keap-1 signal transduction pathway regulating the IL-6 and IL-1β cytokine productions, which increase endometrial receptivity, as well. The NRF2 transcription factor increases the expression of the iron exporter ferroportin in HEC-1A cells activating iron release towards JEG-3 trophoblast cells. The iron measurements show that iron content of endometrial cells decreases while heme concentration increases at FKN treatment. At the same time, the trophoblast cells show increased iron uptake and total iron content. Based on our results it seems that FKN enhances the establishment of endometrial receptivity and meanwhile it regulates the iron homeostasis of endometrium contributing to the iron availability of the trophoblast cells and the embryo.

Purinergic Signaling in Endometriosis-Associated Pain

Endometriosis is an estrogen-dependent gynecological disease, with an associated chronic inflammatory component, characterized by the presence of endometrial tissue outside the uterine cavity. Its predominant symptom is pain, a condition notably altering the quality of life of women with the disease. This review is intended to exhaustively gather current knowledge on purinergic signaling in endometriosis-associated pain. Altered extracellular ATP hydrolysis, due to changes in ectonucleotidase activity, has been reported in endometriosis; the resulting accumulation of ATP in the endometriotic microenvironment points to sustained activation of nucleotide receptors (P2 receptors) capable of generating a persistent pain message. P2X3 receptor, expressed in sensory neurons, mediates nociceptive, neuropathic, and inflammatory pain, and is enrolled in endometriosis-related pain. Pharmacological inhibition of P2X3 receptor is under evaluation as a pain relief treatment for women with endometriosis. The role of other ATP receptors is also discussed here, e.g., P2X4 and P2X7 receptors, which are involved in inflammatory cell-nerve and microglia-nerve crosstalk, and therefore in inflammatory and neuropathic pain. Adenosine receptors (P1 receptors), by contrast, mainly play antinociceptive and anti-inflammatory roles. Purinome-targeted drugs, including nucleotide receptors and metabolizing enzymes, are potential non-hormonal therapeutic tools for the pharmacological management of endometriosis-related pain.

Involvement of natural killer cells in the pathogenesis of endometriosis in patients with pelvic pain

Objectives

To detect the involvement of immune cells in the pathogenesis of endometriosis in patients with stable status or pelvic pain.

Methods

Blood was collected from patients with endometriosis with and without pelvic pain. Natural killer (NK) and Th17 cells were analyzed by flow cytometry, and secretion of inflammatory cytokines (tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-7) was verified by enzyme-linked immunosorbent assay. We isolated immune cells from blood by density-gradient centrifugation to investigate the expression of functional molecules including sterile alpha motif domain-containing protein 9 (SAMD9), Ral guanine nucleotide dissociation stimulator-like 2 (RGL2), early growth response protein 1, and Akirin2. We also searched the BIOGPS database for protein expression profiles.

Results

SAMD9 and RGL2 expression levels were significantly upregulated in patients with pelvic pain. Furthermore, lysophosphatidic acid receptor 1 expression was higher in endometrial tissues from patients with pelvic pain, and was mainly localized in stromal and glandular epithelial cells in ectopic lesions.

Conclusion

NK cells play an important role in the pathogenesis of endometriosis in patients with pelvic pain. Suppressing the cytotoxic activity of NK cells may thus help to reduce the progression of pelvic pain in patients with endometriosis.

Chemokine expression profiles of ovarian endometriotic stromal cells in three-dimensional culture

Endometriosis is a chronic inflammatory disease which is associated with aberrant chemokine expression. We have established a three-dimensional (3D) floating collagen gel culture of human endometriotic cyst stromal cells (ECSCs) as an in vitro model of early-stage fibrosis formation in endometriosis. We evaluated the gene expression profiles of 3D-cultured ECSCs using a gene expression microarray. We identified and confirmed with reverse transcription-polymerase chain reaction that mRNA levels of CXCL1, CXCL2, CXCL3, CXCL8, and CCL20 in 3D-cultured ECSCs were significantly higher than in 2D-cultured ECSCs. The protein levels of CXCL1, CXCL2, CXCL8, and CCL20 in the supernatant of 3D-cultured ECSCs were significantly higher than in 2D-cultured ECSCs. It has been suggested that the 3D-culture model of ECSCs is more suitable for in vitro endometriosis research than 2D-culture. This microarray data provides a new platform to identify the candidate genes involved in the pathogenesis of endometriosis which could be masked in conventional 2D-culture.

CCL19/CCR7 contributes to the pathogenesis of endometriosis via PI3K/Akt pathway by regulating the proliferation and invasion of ESCs

PROBLEM

The level of CCL19 increased in the peritoneal fluid of women with endometriosis, but the precise mechanism of CCL19/CCR7 in the pathogenesis of endometriosis remains unknown.

METHODS

ELISA and immunohistochemistry were performed to analyze CCL19/CCR7 expressions in peritoneal fluid and endometrium from women with endometriosis (n = 38) and controls (n = 32). Cell proliferation and transwell invasion assays were applied to detect proliferation and invasion of human endometrial stromal cells (ESCs). Expressions of Bcl2, MMP2, MMP9, and p-AKT/AKT were analyzed by Western blot.

RESULTS

Peritoneal fluid concentration of CCL19 in patients with endometriosis was higher than that in controls. Those patients with moderate/severe endometriosis had significantly higher peritoneal fluid concentrations of CCL19 compared to those with minimal/mild endometriosis. Higher CCL19 and CCR7 were found in the endometrium with endometriosis compared to control. CCL19 significantly enhanced ESC proliferation and invasion through CCR7 via activating PI3K/Akt signal pathways. CCL19/CCR7 interaction significantly enhanced phosphorylation of Akt, Bcl2, MMP2, and MMP9 in ESCs.

CONCLUSION

These data indicate CCL19/CCR7 contributes to proliferation and invasion of ESCs, which are conducive to the pathogenesis of endometriosis through activating PI3K/Akt pathway.

Redox regulation of microRNAs in endometriosis-associated pain

Endometriosis is a chronic, painful condition with unknown etiology. A differential expression of microRNAs in the endometriotic tissues from women with endometriosis with pain compared to those without suggested a plausible role for miRNA or epigenetic mechanisms in the etiology of endometriotic pain. The peritoneal milieu is involved in maintenance of endometriotic lesion and nociception. We recently showed the mechanistic role for oxidized-lipoproteins (ox-LDLs) present in peritoneal fluid (PF) in endometriosis and pain. We explored the possibility of ox-LDLs modulating the expression of miRNAs in a manner similar to PF from women with endometriosis. Expression levels of miRNAs and their predicted nociceptive and inflammatory targets were determined in PF and ox-LDL treated human endometrial cell-lines. Samples from IRB-approved and consented patients with and without endometriosis or pain were used. These were compared to endometrial cell-lines treated with various forms of oxidized-lipoproteins. RNA (including miRNAs) were isolated from treated endometrial cells and expression levels were determined using commercial miRNome arrays. Cell lysates were used in immunoblotting for inflammatory proteins using a protein array. Twenty miRNAs including isoforms of miR-29, miR-181 and let-7 were mutually differentially expressed in cells treated with PF from endometriosis patients with pain and those treated with ox-LDL components. The ox-LDLs and endo-PF treatment also produced significant overexpression of microRNA predicted target genes nerve growth factor, interleukin-6 and prostaglandin E synthase and overexpression of their downstream protein targets Mip1α and MCP1. This study showed similarities between miRNA regulation in PF from endometriotic women and ox-LDLs present in abundance in the PF of these women. Key miRNAs responsible for targeting nociceptive and inflammatory molecules were downregulated in the presence of ox-LDLs and endo-PF, thus playing a role in the etiology of endometriotic pain. These redox-sensitive miRNAs can be of potential use as targets in the treatment of endometriosis-associated pain.

Long non-coding RNA LINC00261 inhibits cell growth and migration in endometriosis

AIM

A previous study reported that LINC00261 is significantly downregulated in human ectopic endometrial tissues. The present study aimed to explore whether LINC00261 is functional in endometriosis cell proliferation, apoptosis and migration.

METHODS

By transfecting human endometriosis cell line CRL-7566 with plasmids containing LINC00261, we successfully established the cell CRL-7566/LINC00261 with a high LINC00261 expression level. Cell-counting kit-8 and colony formation assays were conducted to evaluate the effect of LINC00261 on cell proliferation, and flow cytometry analysis and transwell migration assay were conducted to evaluate its effect on cell apoptosis and cell migration, respectively.

RESULTS

Cell-counting kit-8 and colony formation assays both indicated that LINC00261 could inhibit cell proliferation in CRL-7566. Flow cytometry analysis confirmed that LINC00261 mediated inhibition of cell proliferation, which might be a consequence of inducting apoptosis. Furthermore, transwell migration assay indicated that LINC00261 could inhibit cell migration in endometriosis.

CONCLUSION

LncRNA LINC00261 is capable of inhibiting cell growth and migration in endometriosis.

Ping-Chong-Jiang-Ni Formula Induces Apoptosis and Inhibits Proliferation of Human Ectopic Endometrial Stromal Cells in Endometriosis via the Activation of JNK Signaling Pathway

Endometriosis is a common gynecological condition in childbearing age women and its therapy in modern medicine achieves usually temporary cure. Ping-Chong-Jiang-Ni formula (PCJNF), a Chinese herbal medicine (CHM), was shown to be clinically effective on endometriosis. Meanwhile, c-Jun N-terminal kinase (JNK) signaling pathway was involved in the therapeutic process of CHM on endometriosis. Here, we explored the effect of PCJNF on the ectopic endometrial stromal cells (EESCs) from endometriosis and test whether JNK signaling was involved. After being treated with PCJNF-containing serum obtained from Sprague Dawley rat, cell proliferation, migration, invasion, and apoptosis were evaluated in EESCs, and the total and phosphorylated JNK, ERK, and p38 proteins were detected. Our results showed that PCJNF could suppress cell proliferation, migration, and invasion and induce apoptosis in EESCs. The suppressed proliferation and increased apoptosis were dependent on JNK activation. Additionally, PCJNF caused cell cycle arrest at G2/M phase and this effect was mediated by JNK signaling, while the decreased cell migration and invasion treated by PCJNF were independent of JNK signaling. In summary, our results provided the first evidence that PCJNF could suppress cell proliferation, migration, and invasion, while increasing apoptosis in EESCs, and the suppressed proliferation and enhanced apoptosis were mediated by JNK signaling.