Abstract B020: Myofibroblasts induce neuroplasticity to promote pancreatic inflammation and cancer progression

Abstract

Pancreatic ductal adenocarcinoma (PDAC) co-opts the peripheral nervous system through nerve hypertrophy, axonogenesis, and perineural invasion; these processes correlate with patient morbidity and mortality. Prior work has shown that autonomic nerves directly modulate neoplastic cells in PDAC, but whether cancer-associated fibroblasts (CAFs) participate in neural remodeling remains unknown. We and others previously identified three main CAF populations, myofibroblastic CAFs (myCAFs), inflammatory CAFs (iCAFs), and antigen-presenting CAFs (apCAFs), that are activated by distinct signaling mechanisms dependent on their proximity to cancer cells (TGF-β, IL-1α) or their cellular origin (mesothelial cells). Using thick tissue sections, we identified dense neo-innervation near myCAFs in preinvasive pancreatic intraepithelial neoplasms. Single-cell analysis of a CAFs dataset from KPC tumors revealed an enrichment of axon guidance-related pathways primarily within the myCAFs population, with certain pathways also enriched in the apCAFs population. To specifically capture the neurotropic interactions mediated by CAFs, we developed a novel gene signature comprising secreted factors and membrane-bound receptors that regulate neurite outgrowth, while excluding intracellular neuronal pathways, and confirmed its enrichment in myCAFs. We validated the clinical relevance of these findings using scRNA-seq datasets from primary human PDAC tissues and found a significant enrichment of this signature in the myCAF population. Mechanistically, TGF-β produced during inflammation and neoplasia triggers myofibroblast formation, and myCAFs produce axon guidance molecules that recruit sympathetic nerves. The ablation of Tgfbr2 expression in pancreatic stellate cells in vitro prevents their activation into myCAFs and the secretion of axon guidance cues. Similarly, the ablation of Tgfbr2 in fibroblasts (Pdgfra CreERT2 ; Tgfbr2 fl/fl ) in vivo led to a decrease in neo-axonogenesis induced in a chronic pancreatitis model. Norepinephrine released by sympathetic nerves activates myofibroblast cultures in vitro through the alpha-1 adrenergic receptor, driving an increase in intracellular calcium and the phosphorylation of ERK and CREB. In vivo, sympathetic nerve depletion impairs stromal activation and PDAC growth. Lastly, we generated a chemogenetic model to mimic the alpha-1 adrenergic downstream signaling pathway specifically in fibroblasts (Pdgfra CreERT2 ; CAG-LSL-Gq-DREADD) and demonstrated that the activation of this pathway exacerbated pancreatic inflammation and neoplasia. Therefore, beyond direct epithelial effects, sympathetic nerves promote pancreatitis and PDAC by co-opting myofibroblasts and myCAFs as disease amplifiers, highlighting CAF subtype–specific stromal interactions as putative therapeutic targets.