P3.48. THE SILENT NOCICEPTORS AS REGULATORS OF IMMUNE CELLS ACTIVITY
Łukasz Pietras1, Ewelina Krzywińska1, Mateusz Kucharczyk1,2
1 Łukasiewicz Research Network - PORT Polish Center for Technology Development, Stabłowicka 147, Wrocław, Poland.
2 Wolfson Sensory, Pain and Regeneration Centre, King’s College London, SE1 1UL London, UK
INTRODUCTION: Tumors represent highly complex cellular assemblies, characterized by extensive vascularization and innervation. Recent evidence highlights a significant role of sympathetic and sensory innervation in promoting tumor progression. This has been attributed to the influence on immune cells – specifically through the release of the neuropeptide calcitonin gene-related peptide from nociceptive sensory neurons, leading to the cytotoxic T-cells exhaustion. Our recent work evidenced that this effect may be caused by silent nociceptors, a unique subpopulation of peptidergic nociceptors, which become "awakened" due to regulatory activity within the tumor niche.
AIM(S): To characterize interaction between silent nociceptors and the immune system in healthy transgenic mice.
METHOD(S): The study was conducted on ChRNA3-ERT2-Cre mice labelling silent nociceptors. Examination of the immune response was performed following selective opto- and chemogenetic modulation of silent nociceptors activity by high-throughput mass spectrometry and flow cytometry (FACS) of tibial bone marrow, as well as detailed immunohistochemistry and confocal microscopy analysis.
RESULTS: Immunohistochemical validation confirmed the effectiveness of optogenetic activation and chemogenetic block of silent nociceptors activity. Mass spectrometry analysis of mouse tibial marrow demonstrated the secretion of various neuropeptides by silent nociceptors known to influence immune system activity. FACS analysis confirmed significant alterations in the proportion of active and inactive cytotoxic T-cells in response to in vitro treatment with various neuropeptides and following silent nociceptors modulation in vivo.
CONCLUSIONS: The findings substantiate significant impact of silent nociceptors activity on immune system function. The opto- and chemogenetic modulation provides a robust experimental framework to facilitate future phenotyping in a context of bone tumors. The data acquired herein provide a valuable and necessary basis for these prospective studies.
FINANCIAL SUPPORT: Funded by The Polish National Agency for Academic Exchange Strategic Partnerships Grant (BNI/PST/2023/1/00132/U/00001), held by M. Kucharczyk.