PROJECT SUMMARY Endometriosis is an inflammatory disease affecting the peritoneal cavity that has been treated predominantly with endocrine modulators to impose growth restriction through suppression of estrogen action. Worldwide, there are 28 development or marketed products that address the endocrine axis of endometriosis. However, few, if any drug discovery efforts address the non-hormonal axes of this disease as stand-alone therapy, or as sequential therapy during hiatus from endocrine-suppressing agents. The pathophysiology shared by deep infiltrating endometriosis, superficial peritoneal endometriosis and ovarian endometrioma includes epithelial- mesenchymal trans-differentiation (EMT) and fibroblast-myofibrobocyte trans-differentiation. The focus of this proposed research is to develop novel, potent, highly selective inhibitors of Jun N-terminal kinase (JNK-I) that can interrupt trans-differentiation pathways that are the pathological basis for lesion survival. Our preliminary results with bentamipimod (JNK-I) have validated this approach demonstrating equivalent regression of lesions as were obtained with GnRH antagonist in primate models. Furthermore, results in rodent, non-human primate models, and in humans (Phase II results) demonstrate regression of lesions without impact on eutopic endometrium, or endogenous hormone levels. Our project integrates reproductive biologists, immunologists, medicinal chemists and biomedical engineers with demonstrated leadership in academic and pharmaceutical research to discover novel JNK-I and characterize their potential for patients. Our program incorporates state-of-the-art technologies to help achieve our objectives. In Specific Aim 1, we will optimize affinity and permeability of c-jun N-terminal kinase (JNK-I) obtained following two rounds of selection from our DNA-encoded Chemistry Technology (DEC-Tec) libraries at Baylor College of Medicine containing over 4 billion compounds. The efficacy of these compounds in vitro will be evaluated in established cell lines and in primary human endometrial stromal cells. In Specific Aim 2, we will compare the efficacy of novel JNK-I prepared at the Center for Drug Discovery to tanzisertib in a previously validated mouse model of endometriosis with endometrium-specific ER? overexpression (ER?:OE) that enables evaluation of anti-inflammatory therapies amidst elevated ER? response and compromised progesterone sensitivity. These comparisons have never been generated for JNK-I and provide an opportunity to assess treatment efficacy based on improved potency of JNK-I. In Specific Aim 3, we will demonstrate that emerging diagnostics of the menstrualome can stratify patients for future JNK-I therapy based on their ex vivo cytokine production from macrophages and NK cells obtained from menstrual effluent. The objectives for all three Specific Aims generate new information regarding the action of JNK-I in endometriosis for both known and novel JNK-I.