Project Summary/Abstract Pulpitis is a painful disease of the dental pulp tissue, which is treated by expensive and invasive dental procedures such as root canal treatments and tooth extractions. A limited understanding of the intermingling mechanisms of inflammation and pain involving the innate immune response and the dense innervation of the pulp tissue jointly, precludes the precise application of conservative treatments and the development of novel pain management strategies. In this project, the principal investigator will focus on the roles of neutrophils in nerve injury and pain during pulpitis, and how nociceptive neurons modulate innate immune response. Moreover, she proposes to study neuro-immune interactions during pulpitis not only limited within the pulp tissue but in the pulp-periodontium complex where these two neighboring tissues are neuroanatomically connected. The central hypothesis of the study is that during pulpitis, inflammation is present in the pulp and also in the periodontium, and it is modulated by nociceptive neurons, and driven by neutrophils which regulate sensory and pain outcomes. In Aim 1 of the K99 phase, Dr. Erdogan will identify neutrophil-driven nerve injury and pain outcomes during pulpitis by using different clinically informed animal models of pulpitis, perform pharmacological manipulations of neutrophils, use tissue-clearing and whole-mount imaging, single-nuclei RNA sequencing and in-situ hybridization to detect anatomical and transcriptional changes of neurons. She will also use evoked and non- evoked pain behavior assays. In Aim 2 of the K99 phase, Dr. Erdogan will identify the impact of silencing nociceptive neurons on neutrophil recruitment and responses in the pulp tissue during pulpitis. She will use chemogenetic and DREADD-based approaches to silence certain subsets of neurons and perform flow cytometry and sensitive ELISA-based assays to assess innate immune responses. In the R00 phase of the award, in Aim 3, Dr. Erdogan will identify the mechanisms and unique signatures of inflammation in the neighboring periodontium during pulpitis, focusing on neuronal-driven inflammation, by using in-vivo dental pulp neuron activation models and pulpitis models. She will investigate neurogenic inflammatory mechanisms, and outcomes and establish the framework and understanding of how the neighboring periodontium anticipates and responds to diseases affecting the pulp tissue. During the K99 mentored phase, Dr. Erdogan will learn the skills and cutting-edge techniques necessary to accomplish the proposed research under the guidance of expert scientists Dr. Isaac M. Chiu (primary mentor), Dr. Jennifer L. Gibbs (co-mentor), Dr. William Renthal and Dr. Thomas Van Dyke (collaborators) who collectively have an extensive track record of training scientists and dentist-scientists. The proposed scientific and career development training during the K99 phase of the award will support Dr. Erdogan in her transition to being an independent dentist-scientist.

Project Narrative Pulpitis, or inflammation of the dental pulp tissue, is a debilitating painful disease and one of the main causes of invasive dental procedures. In this project, we investigate the roles of neutrophils in sensory afferent injury and pain and the role of sensory neurons in modulating innate immune response in pulpitis. The project is relevant to NIDCR’s mission because of its potential to improve dental health by investigating neuro-immune mechanisms driving dental pain and inflammation.