Host Immune and Epithelial Cell Signaling Pathways

Host Immune and Epithelial Cell Signaling Pathways represent the integrated communication networks between the body's barrier-forming epithelial cells and the underlying immune system [1]. These pathways, such as the JAK-STAT, NF-κB, and MAPK cascades, coordinate the host's response to environmental stimuli, pathogens, and tissue damage [2]. Epithelial cells act as the first line of defense, sensing environmental cues and secreting cytokines or chemokines that recruit and activate immune cells [3]. In turn, immune cells produce factors that modulate epithelial proliferation, permeability, and antimicrobial peptide production [1]. Dysregulation of this bidirectional crosstalk is a central driver in the pathogenesis of chronic inflammatory diseases such as ulcerative colitis, Crohn's disease, and asthma [4]. It also plays a critical role in the "cytokine storm" observed in severe respiratory infections like COVID-19 [2]. While the term describes a broad biological system rather than a single molecular entity, it encompasses numerous high-value therapeutic targets [5]. Drugs like Janus kinase inhibitors and monoclonal antibodies against cytokines (e.g., TNF-alpha, IL-17) are used to modulate specific nodes within these pathways to restore tissue homeostasis [5]. [1] Nature Reviews Gastroenterology & Hepatology (2020) https://www.nature.com/articles/s41575-020-0283-9; [2] Frontiers in Immunology (2018) https://www.frontiersin.org/articles/10.3389/fimmu.2018.02531/full; [3] NIH/NCBI (2020) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7151811/; [4] PubMed (2020) https://pubmed.ncbi.nlm.nih.gov/32359459/; [5] Immunity (2019) https://www.cell.com/immunity/fulltext/S1074-7613(19)30082-0

Other names

Epithelial-immune crosstalkHost-pathogen signaling pathwaysMucosal immune axisEpithelial-immune cell interactions

Drugs targeting these pathways typically function by inhibiting specific intracellular signaling molecules, such as Janus kinases (JAKs), or by neutralizing extracellular cytokines and their receptors (e.g., TNF, IL-6, IL-17) to disrupt the inflammatory feedback loop between epithelial and immune cells [5].