Pro-resolving lipid mediator receptors as therapeutic targets for endometriosis pain

Endometriosis-associated pain is an important driver of opioid use in women. Endometriosis is an estrogen sensitive, inflammatory disease that affects ~10% of women of childbearing age and is found in half of women with chronic pelvic pain. Endometriosis increases the likelihood of chronic opioid use, opioid dependence/abuse, and opioid overdose. Endometriosis is currently treated with NSAIDS, hormonal therapy targeting estrogen production, and surgery, but these options are not durably effective for ~30% of patients. To identify new therapeutic targets, we have developed and validated a mouse model of endometriosis pain. Using that model, we discovered that DHA, EPA, and several specialized pro-resolving lipid mediators (SPMs) rapidly abolish endometriosis-associated pain and shrinks lesions. Unfortunately, poor stability and pharmacokinetic properties render SPMs poor drug leads. To leverage the anti-endometriosis activity of these molecules, the most active SPMs, their receptors, and the cell types where they act must be identified. We aim to do this, with the long-term goal of identifying molecules with potent anti-endometriosis activity. Most SPMs are commercially available and we will use our validated mouse model of endometriosis pain to identify the most active of these. In the few cases where high affinity SPM receptors are known, they activate G-protein coupled receptors (GPCRs). To identify receptors for all available SPMs, we will use the PRESTO- Tango system. This contains a near-complete library of human non-olfactory GPCRs, which are coupled via arrestin activation to luciferase expression. We will then identify the G-protein(s) that couple to these GPCRs in the context of SPM signaling. We will also use our single-cell RNAseq data from human lesions and newly- generated scRNAseq data from our mouse model to identify the cell types that mediate SPM signaling. This will allow appropriate cell-based assays to be identified for a therapeutic development program. We will also measure the effect of SPMs on the transcriptional profile of relevant cell types in vivo, in order to begin to understand how SPMs relieve pain and reduces lesion size. This will provide important pharmacodynamic markers of SPM action that can be used to measure target engagement in future human trials. Completion of the proposed work will identify a novel, druggable target for endometriosis therapy. As this is expected to be a GPCR, common strategies like high-throughput screening (with which we have experience) can then be used to identify pharmacophores that lack the liabilities present in SPMs. Although additional target validations work (e.g., with knockout mice) will remain, these studies will provide important knowledge about the mechanism by which SPMs reduce endometriosis-associated pain and lesion growth. Thus, the knowledge to be gained by these studies will represent an important advance toward the development of desperately needed novel therapeutics for endometriosis. Development of such drugs will improve the lives of many women and decrease the use of opiods to treat this disease, thereby improving many lives.