*2.8. PHF19, a Key Co-Factor in the miR-155-JARID2-EZH2 Crosstalk in Endometriosis*

The polycomb-like proteins, PHF1 and PHF19 are critical components of PRC2 complex, both of which showed enrichment after EZH2 IP in the endo PF treated cells (fold change, 13.31 and 4.76-fold, respectively). Both these proteins are shown to work with the PRC2 complex in the manner similar to JARID2 in which they form subcomplexes with PRC2 core components and modulate the enzymatic activity of PRC2 and its recruitment [52,53]. Interestingly, PHF19 is also shown to interact with miR-155 to bring the PRC2 complex to its target [54]. In order to validate the ChIP findings, mRNA expression of *PHF19* was determined in the PF treated endometrial cells using qPCR. mRNA analysis revealed that *PHF19* was upregulated in endometrial cells treated with both control and endo PF when compared to media alone cells with the expression of *PHF19* reaching almost 11.5-fold in the endo PF treated cells (*p* = 0.0474), suggesting that PHF19 may be working along with miR-155 to bring the PRC2 complex to its target and promote endometriosis (Figure 8). *Int. J. Mol. Sci.* **2021**, *22*, 3492 10 of 19 [52,53]. Interestingly, PHF19 is also shown to interact with miR-155 to bring the PRC2 complex to its target [54]. In order to validate the ChIP findings, mRNA expression of *PHF19* was determined in the PF treated endometrial cells using qPCR. mRNA analysis revealed that *PHF19* was upregulated in endometrial cells treated with both control and endo PF when compared to media alone cells with the expression of *PHF19* reaching almost 11.5-fold in the endo PF treated cells (*p* = 0.0474), suggesting that PHF19 may be working along with miR-155 to bring the PRC2 complex to its target and promote endometriosis (Figure 8).

**Figure 8.** mRNA expression of PHF19 in endometrial cells treated with PF. When Ishikawa endometrial cells were treated with endo PF, expression of *PHF19* was shown to increase 11.50-fold relative to media alone treated cells (*p* = 0.0474). \* *p* < 0.05 compared to media alone. **Figure 8.** mRNA expression of PHF19 in endometrial cells treated with PF. When Ishikawa endometrial cells were treated with endo PF, expression of *PHF19* was shown to increase 11.50-fold relative to media alone treated cells (*p* = 0.0474). \* *p* < 0.05 compared to media alone.
