Molecular and Cellular signaling mechanisms of TRPV4 in non-neuronal cells: a pathophysiological relevance for migraine pain.

ABSTRACT Transient receptor potential (TRP) ion channels have been implicated in the pathophysiology of migraine, a neurological disorder with incapacitating episodic headaches. TRPV4 Ca++-permeable ion channels are expressed and function in trigeminal (TG) sensory neurons, also in keratinocytes and in mast cells, which are both innervated by TG sensory neurons, in head-face skin and meninges. My main objective is to define TRPV4 dependent mechanisms in non-neuronal cells, specifically skin keratinocytes and meningeal mast cells, and how these can tune migraine pain-relevant trigeminal nociceptor neurons. One particular intriguing and understudied feature of migraine and other pathologic pain is racial divergence of suffering, identified as more severe in African Americans. An obstacle toward rational understanding is simply a lack of mechanistic studies that elucidate this phenomenon. Based on my preliminary experiments, namely TRPV4 channels becoming UVB-sensitized more in skin keratinocytes from African Americans than from Caucasians, I also intend to elucidate racial differences in forefront trigeminal pain signaling that depend on TRPV4 in keratinocytes and mast cells. My central hypothesis is that hypersensitization of TRPV4 channels in skin keratinocytes and meningeal mast cells contributes to development and perpetuation of inflammatory pain in migraine, and that this regulation is modulated by racial background. To test this hypothesis, I propose two aims: 1) To determine how inflammation alters TRPV4 channel sensitization in keratinocytes and how skin pigmentation determines the channel’s sensitivity; 2) To characterize the contribution of TRPV4 in mast cells in migraine pain. Yield from this proposal will fill a significant gap in understanding how TRPV4 facilitates the crosstalk of keratinocytes and mast cells with TG neurons that innervate them and contribute to the pathophysiology of migraine. Deconstructing these processes will set the stage for regulating both mast cells’ and keratinocytes’ powerful pro-inflammatory/pro- algesic organismal function. The proposed quest for identifiable racial differences of biologic signaling in the interrogated cell lineages will position us to leverage these findings toward personalized medicine. With the guidance from my team of mentors, whose expertise ranges across the pertinent areas of study relevant for this proposal, and with whom I am already effectively collaborating, I propose to effectively train for my further career development. I expect to: 1) Gain experience in collaborations and team formation, 2) Expand my skill- set platform in laboratory-based techniques such as modeling animal behavior and mast cell cellular and molecular assays, 3) Acquire and apply advance statistical analysis skills to my research, 4) Expand my communication skills, including scientific writing and presentation, and build on my existing set of managerial and leadership skills. The proposed training will equip me with unique a set of skills needed to become an Independent laboratory-based investigator in multidisciplinary approaches for studying inflammatory pain.