👤 Menny Kirma

Endometriosis is a debilitating gynecologic disorder that affects ∼10% of women of reproductive age. Endometriosis is characterized by growth of endometriosis lesions within the abdominal cavity, generally thought to arise from retrograde menstruation of shed endometrial tissue. While the pathophysiology underlying peritoneal endometriosis lesion formation is still unclear, the interaction between invading endometrial tissue and the peritoneal mesothelial lining is an essential step in lesion formation. In this study, we assessed proteomic differences between eutopic endometrial stromal cells (ESCs) from women with and without endometriosis in response to peritoneal mesothelial cell (PMC) exposure, using single-cell cytometry by time-of-flight (CyTOF). Co-cultured primary eutopic ESCs from women with and without endometriosis with an established PMC line were subjected to immunostaining with a panel of Maxpar CyTOF metal-conjugated antibodies (n = 28) targeting cell junction and mesenchymal markers, which are involved in cell-cell adhesions and epithelial-mesenchymal transition. Exposure of the ESCs to PMCs resulted in a drastic shift in cellular expression profiles in ESCs derived from endometriosis, whereas little effect by PMCs was observed in ESCs from non-endometriosis subjects. The transcription factor SNAI1 was consistently repressed by PMC interactions. ESCs from endometriosis patients are unique in that they respond to PMCs by undergoing changes in adhesive properties and mesenchymal characteristics that would facilitate lesion formation. Show less

Diaminopimelate aminotransferase (DAP-AT) is an enzyme in the lysine-biosynthesis pathway. Conversely, ALD1, a close homologue of DAP-AT in plants, uses lysine as a substrate in vitro. Both proteins require pyridoxal-5'-phosphate (PLP) for their activity. The structure of ALD1 from the flowering plant Arabidopsis thaliana (AtALD1) was solved at a resolution of 2.3 Å. Comparison of AtALD1 with the previously solved structure of A. thaliana DAP-AT (AtDAP-AT) revealed similar interactions with PLP despite sequence differences within the PLP-binding site. However, sequence differences between the binding site of AtDAP-AT for malate, a purported mimic of substrate binding, and the corresponding site in AtALD1 led to different interactions. This suggests that either the substrate itself, or the substrate-binding mode, differs in the two proteins, supporting the known in vitro findings. Show less