Identification of the M-CSF Receptor in Endometriosis by Immunohistochemistry and RT-PCR

Inhibition of CSF1R and KIT With Pexidartinib Reduces Inflammatory Signaling and Cell Viability in Endometriosis

Endometriosis is a common and debilitating disease, affecting ∼170 million women worldwide. Affected patients have limited therapeutic options such as hormonal suppression or surgical excision of the lesions, though therapies are often not completely curative. Targeting receptor tyrosine kinases (RTKs) could provide a nonhormonal treatment option for endometriosis. We determined that 2 RTKs, macrophage-colony stimulating factor 1 receptor (CSF1R) and mast/stem cell growth factor receptor KIT (KIT), are overexpressed in endometriotic lesions and could be novel nonhormonal therapeutic targets for endometriosis. The kinase activity of CSF1R and KIT is suppressed by pexidartinib, a small molecule inhibitor that was recently approved by the US Food and Drug Administration. Using immunohistochemistry, we detected CSF1R and KIT in endometriotic tissues obtained from peritoneal lesions, colorectal lesions, and endometriomas. Specifically, we show that KIT is localized to the epithelium of the lesions, while CSF1R is expressed in the stroma and macrophages of the endometriotic lesions. Given the high epithelial expression of CSF1R and KIT, 12Z endometriotic epithelial cells were used to evaluate the efficacy of dual CSF1R and KIT inhibition with pexidartinib. We found that pexidartinib suppressed activation in 12Z cells of JNK, STAT3, and AKT signaling pathways, which control key proinflammatory and survival networks within the cell. Using quantitative real-time polymerase chain reaction, we determined that pexidartinib suppressed interleukin 8 (IL8) and cyclin D1 (CCND1) expression. Lastly, we demonstrated that pexidartinib decreased cell growth and viability. Overall, these results indicate that pexidartinib-mediated CSF1R and KIT inhibition reduces proinflammatory signaling and cell viability in endometriosis.

Circulating Inflammatory Cytokines and Female Reproductive Diseases: A Mendelian Randomization Analysis

CONTEXT

Extensive studies have provided considerable evidence suggesting the role of inflammation in the development of female reproductive diseases. However, causality has not been established.

OBJECTIVE

To explore whether genetically determined circulating levels of cytokines are causally associated with female reproductive diseases and discover potential novel drug targets for these diseases.

METHODS

Instrumental variables (IVs) for 47 circulating cytokines were obtained from a genome-wide association study (GWAS) meta-analysis of 31 112 European individuals. Protein quantitative trait loci and expression quantitative trait loci close to genes served as our IVs. Summary data of 9 female reproductive diseases were mainly derived from GWAS meta-analysis of the UK biobank and FinnGen. We elevated the association using the Wald ratio or inverse variance-weighted Mendelian randomization (MR) with subsequent assessments for MR assumptions in several sensitivity and colocalization analyses. We consider a false discovery rate <0.05 as statistical significance in MR analyses. Replication studies were conducted for further validation, and phenome-wide association studies were designed to explore potential side effects.

RESULTS

Our results indicated that high levels of macrophage colony-stimulating factor (MCSF), growth-regulated oncogene-alpha (GROα), and soluble intercellular adhesion molecule-1 were associated with increased risks of endometriosis, female infertility, and pre-eclampsia, respectively. High platelet-derived growth factor-BB (PDGF-BB) levels that reduced the risk of ovarian aging were also supported. Replication analysis supported the relationship between GROα and female infertility, and between MCSF and endometriosis.

CONCLUSION

We identified 4 correlated pairs that implied potential protein drug targets. Notably, we preferred highlighting the value of PDGF-BB as a drug target for ovarian aging, and MCSF as a drug target for endometriosis.

CSF-1-induced DC-SIGN+ macrophages are present in the ovarian endometriosis

BACKGROUND

Researchers have found that macrophages are the predominant cells in the peritoneal fluid (PF) of endometriosis patients. CSF-1 has been found to accumulate in the lesions and PF of endometriosis patients, and CSF-1 induces THP-1-derived macrophages to polarize toward a CD169⁺ DC-SIGN⁺ phenotype. Does the cytokine CSF-1 induce monocytes to differentiate into macrophages with a DC-SIGN⁺ phenotype in endometriosis?

METHODS

The level of CSF-1 in the endometrium of control subjects, and the eutopic, and ectopic endometrium of endometriosis patients was evaluated by real-time polymerase chain reaction (qRT-PCR) and was determined by enzyme-linked immunosorbent assay (ELISA) in the PF of control and endometriosis patients. CSF-1 expression was examined with a MILLIPLEX MAP Mouse Cytokine/Chemokine Magnetic Bead Panel. DC-SIGN⁺ macrophages were detected by immunohistochemical staining of tissues and flow cytometric analysis of the PF of control subjects (N = 25) and endometriosis (N = 35) patients. The phenotypes and biological activities of CSF-1 -induced macrophages were compared in an in vitro coculture system with peripheral blood lymphocytes from control subjects.

RESULTS

In this study, we found that the proportion of DC-SIGN⁺ CD169⁺ macrophages was higher in the abdominal immune microenvironment of endometriosis patients. CSF-1 was primarily secreted from ectopic lesions and peritoneum in mice with endometriosis. In addition, CSF-1 induced the polarization of macrophages toward a DC-SIGN⁺ CD169⁺ phenotype; this effect was abolished by the addition of an anti-CSF-1R antibody. CSF-1 induced the generation of DC-SIGN⁺ macrophages, leading to a depressed status of peripheral blood lymphocytes, including a high percentage of Treg cells and a low percentage of CD8⁺ T cells. Similarly, blockade with the anti-CSF-1R antibody abrogated this biological effect.

CONCLUSIONS

This is the first study on the role of DC-SIGN⁺ macrophages in the immune microenvironment of endometriosis. Further study of the mechanism and biological activities of CSF-1-induced DC-SIGN⁺ macrophages will enhance our understanding of the physiology of endometriosis.

IL-34 and CSF-1, deciphering similarities and differences at steady state and in diseases

Although IL-34 and CSF-1 share actions as key mediators of monocytes/macrophages survival and differentiation, they also display differences that should be identified to better define their respective roles in health and diseases. IL-34 displays low sequence homology with CSF-1 but has a similar general structure and they both bind to a common receptor CSF-1R, although binding and subsequent intracellular signaling shows differences. CSF-1R expression has been until now mainly described at a steady state in monocytes/macrophages and myeloid dendritic cells, as well as in some cancers. IL-34 has also 2 other receptors, protein-tyrosine phosphatase zeta (PTPζ) and CD138 (Syndecan-1), expressed in some epithelium, cells of the central nervous system (CNS), as well as in numerous cancers. While most, if not all, of CSF-1 actions are mediated through monocyte/macrophages, IL-34 has also other potential actions through PTPζ and CD138. Additionally, IL-34 and CSF-1 are produced by different cells in different tissues. This review describes and discusses similarities and differences between IL-34 and CSF-1 at steady state and in pathological situations and identifies possible ways to target IL-34, CSF-1, and its receptors.

Impact of medical and surgical treatment of endometriosis on the cure of endometriosis and pain

This endometriosis study evaluates three different treatment strategies (hormonal medication, surgical, or combined treatment) and discusses the influence of endometriosis on the cure of this disease and pain relief. Four hundred and fifty patients with genital endometriosis, aged 18-44 years, were randomly distributed to three treatment groups at the first laparoscopy. They were reevaluated at a second-look laparoscopy (D 426/10), one to two months after the three-month hormonal therapy for groups 1 and 3 and five to six months later for group 2 (surgical treatment alone). Outcome data focussed on the recurrence of symptoms and pain. The three treatment options independent of the initial endoscopic endometriosis classification (EEC) stage including deep infiltrating endometriosis (DIE) achieved an overall cure rate of 50% or higher. The highest cure rate of 60% was achieved by the combined treatment, 55% by the exclusively hormonal therapy, and 50% by the exclusively surgical treatment. An overall pregnancy rate between 55% and 65% was achieved with no significant difference in relation to the therapeutical option.

Increased expression of macrophage colony-stimulating factor and its receptor in patients with endometriosis

OBJECTIVE

To investigate the expression and regulation of colony-stimulating factor 1 (CSF-1) and its receptor, C-FMS, in endometriosis.

DESIGN

In vivo and vitro study.

SETTING

University-based academic medical center.

PATIENT(S)

Reproductive-age women undergoing surgery for benign conditions.

INTERVENTION(S)

Peritoneal and endometrial tissue samples were obtained.

MAIN OUTCOME MEASURE(S)

CSF-1 and C-FMS expression.

RESULT(S)

Significantly higher CSF-1 levels were found in peritoneal fluid of patients with endometriosis compared with control subjects. Ectopic endometriotic tissue had 3.5-fold and 1.7-fold increases in CSF-1 and C-FMS expression, respectively, compared with eutopic tissue. Coculture of endometrial cells from either established cell lines or patient samples with peritoneal mesothelial cells (PMCs) led to increased expression of CSF-1 and C-FMS. A higher but nonsignificant increase in levels of C-FMS and CSF-1 was found in cocultures of endometrial epithelial cells from patients with endometriosis compared with those without endometriosis.

CONCLUSION(S)

Increased CSF-1 levels may contribute to endometriosis lesion formation and progression. Elevation in CSF-1 after coculture of endometrial cells with PMCs suggests that endometrial tissue may be a source of peritoneal CSF-1. Increased C-FMS expression in endometrial cells from women with endometriosis cocultured with PMCs suggests that endometrial tissue involved in lesion formation is highly responsive to CSF-1 signaling.

Apoptosis resistance in endometriosis

INTRODUCTION

In a cytological analysis of endometriotic lesions neither granulocytes nor cytotoxic T-cells appear in an appreciable number. Based on this observation we aimed to know, whether programmed cell death plays an essential role in the destruction of dystopic endometrium. Disturbances of the physiological mechanisms of apoptosis, a persistence of endometrial tissue could explain the disease. Another aspect of this consideration is the proliferation competence of the dystopic mucous membrane.

METHODS

Endometriotic lesions of 15 patients were examined through a combined measurement of apoptosis activity with the TUNEL technique (terminal deoxyribosyltransferase mediated dUTP Nick End Labeling) and the proliferation activity (with the help of the Ki-67-Antigens using the monoclonal antibody Ki-S5).

RESULTS

Twelve out of 15 women studied showed a positive apoptotic activity of 3-47% with a proliferation activity of 2-25% of epithelial cells. Therefore we concluded that the persistence of dystopic endometrium requires proliferative epithelial cells from middle to lower endometrial layers.

CONCLUSION

A dystopia misalignment of the epithelia of the upper layers of the functionalism can be rapidly eliminated by apoptotic procedures.

Colony-stimulating factor-1 exerts direct effects on the proliferation and invasiveness of endometrial epithelial cells

Although macrophage colony-stimulating factor (CSF-1) has been suggested to play a role in maintaining the chronic inflammatory response in endometriosis, our data suggest that CSF-1 may also play a role in early endometriosis lesion formation. We have shown that CSF-1, in an autocrine fashion, has a direct effect on endometrial epithelial cell proliferation and attachment to peritoneal mesothelial cells, early steps in endometriosis lesion formation on the peritoneum.

A potential role for colony-stimulating factor 1 in the genesis of the early endometriotic lesion

OBJECTIVE

To investigate the role(s) of colony-stimulating factor 1 (CSF-1) on the development of early endometriosis in a murine model by comparing rate of lesion formation in mice [1] homozygous for a CSF-1 mutation versus syngeneic controls and [2] after treatment with imatinib, a commercially available tyrosine kinase inhibitor that alters interaction(s) between CSF-1 and its receptor, c-fms.

DESIGN

Prospective, placebo-controlled animal study.

SETTING

Academic medical center.

ANIMALS

Six- to 8-week old female FVB, wild-type C57BL/6, and CSF-1 op/op mice.

INTERVENTION(S)

Endometrial tissue from donor mice was used to induce endometriosis in murine recipients. In some experiments, mice homozygous for a CSF-1 mutation (CSF-1 op/op) were donors or recipients. In other experiments, donor and/or recipient mice received imatinib.

MAIN OUTCOME MEASURE(S)

Histologic confirmation of endometriosis, rate of lesion formation.

RESULT(S)

By 40 hours, recipient mice developed a mean of 7.2 +/- 0.9 endometriotic lesions that had invaded host surfaces, and mesothelial cells had proliferated over the entire surface of the implants. The CSF-1 op/op mice developed significantly fewer (mean 0.9 +/- 0.3) endometriotic lesions versus syngeneic controls. Imatinib treatment resulted in significantly fewer lesions when compared with sham-treated controls.

CONCLUSION(S)

Colony-stimulating factor 1 has a role in establishing early endometriotic lesions. Agents targeting CSF-1 or its actions have therapeutic potential for treating endometriosis.

Induction of endometrial epithelial cell invasion and c-fms expression by transforming growth factor beta

Transforming growth factor beta 1 (TGF-beta1) levels are increased in the peritoneal fluid of endometriosis patients, and endometrial cells express TGF-beta signaling components; however, little is known regarding the role of TGF-beta in endometriosis. Our objective was to examine the effects of TGF-beta1 on (i) the expression of macrophage colony-stimulating factor receptor encoded by the c-fms gene, (ii) transmesothelial invasiveness of endometrial cells, (iii) cellular proliferation and (iv) attachment to peritoneal mesothelial cells (PMCs). Effects of TGF-beta1 on c-fms mRNA expression were determined by real-time RT-PCR and c-fms cell-surface expression by flow cytometry. Effects of TGF-beta1 on the invasiveness of the immortalized endometrial epithelial cell (EEC) line EM42 and primary EECs were examined using a three-dimensional in vitro system modeling the peritoneum. Cellular proliferation and attachment to PMCs were also examined using established techniques. TGF-beta1 had little or no effect on cellular proliferation and endometrial cell attachment to PMCs. TGF-beta1 significantly induced the expression of c-fms mRNA and c-fms cell-surface expression. TGF-beta1 enhanced transmesothelial invasion by EM42 cells and EECs. Antagonists of TGF-beta1 signaling significantly inhibited both the induction of c-fms expression and cellular invasiveness, suggesting that additional studies are warranted to assess the therapeutic potential of TGF-beta antagonists in endometriosis.