The HRH1 Knockout A-549 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed for studying histamine receptor H1 (HRH1) function in a human lung adenocarcinoma background. This product comprises a heterogeneous population of A-549 cells carrying targeted disruptions in the HRH1 gene, generated by CRISPR/Cas9-mediated gene editing, providing a robust loss-of-function model without clonal selection.
The A-549 host cell line is an adherent epithelial cell line derived from human lung adenocarcinoma tissue and is widely used as a model for alveolar type II epithelium. These cells retain key characteristics of pulmonary epithelial cells and are instrumental in cancer biology, respiratory disease research, and drug discovery, particularly for studying inflammatory and oncogenic signaling pathways in the lung.
HRH1 encodes the histamine H1 receptor, a G protein-coupled receptor (GPCR) that primarily couples to G??q/11 proteins. Upon activation by histamine released from mast cells, HRH1 stimulates phospholipase C ?? (PLCB), leading to inositol 1,4,5-trisphosphate (IP3)-mediated calcium mobilization and diacylglycerol (DAG)-dependent protein kinase C (PKC) activation. This triggers downstream mitogen-activated protein kinase (MAPK) cascades, including ERK1/2 (MAPK3/MAPK1), and nuclear factor-??B (NF-??B) signaling via the RELA subunit. The receptor also interacts with regulatory proteins such as ??-arrestin, GRK2, calmodulin, and TRIP6, which modulate signal termination and scaffolding. Consequently, HRH1 drives transcription of pro-inflammatory cytokines (IL-6, IL-8), adhesion molecules (ICAM-1), and enzymes like COX-2, establishing a pivotal role in allergic inflammation and immune modulation. Disruption of HRH1 in these polyclonal cells abolishes histamine-induced calcium signaling and impairs the activation of PLC, MAPK, and NF-??B pathways, leading to marked reductions in cytokine and adhesion molecule expression.
In the A-549 lung adenocarcinoma model, HRH1 knockout provides a valuable tool to dissect histamine-mediated effects on epithelial cell biology. The loss of HRH1 signaling abrogates histamine-driven pro-inflammatory responses that are relevant to asthma, allergic rhinitis, and other hypersensitivity conditions. This model enables investigation of how histamine signaling intersects with oncogenic pathways, as A-549 cells harbor KRAS mutations and active EGFR signaling, offering insights into the potential role of HRH1 in lung tumor microenvironment inflammation and cancer progression.
Researchers can employ these polyclonal knockout cells in a wide range of assays, including histamine-induced calcium flux measurements, western blotting for phosphorylated ERK1/2 and NF-??B p65, RT-qPCR quantification of IL-6 and IL-8 mRNA, flow cytometric analysis of ICAM-1 surface expression, and cytokine secretion profiling following histamine challenge. They are particularly suited for mechanistic studies of allergic asthma, evaluation of antihistamine drug targets (e.g., cetirizine, diphenhydramine), and characterization of histamine signaling in lung cancer. Additionally, NF-??B luciferase reporter assays can be conducted to assess transcriptional activity. For further information or to discuss custom modifications, please contact Ascent Research.
