The GPR75 knockout SK-HEP-1 polyclonal cell product consists of a population of human hepatic adenocarcinoma cells modified by CRISPR/Cas9-mediated disruption of the GPR75 gene. These polyclonal knockout cells provide a loss-of-function model in which the G protein-coupled receptor GPR75 is functionally inactivated. The polyclonal format captures a heterogeneous pool of edited alleles, enabling studies of GPR75-dependent signaling without the clonal selection biases inherent in single-cell-derived knockout lines. This product is designed for researchers investigating the role of GPR75 in hepatic cell contexts related to appetite regulation and metabolic homeostasis.
The host cell line, SK-HEP-1, is a well-established human hepatic adenocarcinoma cell line that displays both epithelial and endothelial characteristics. Originally derived from the ascitic fluid of a patient with liver adenocarcinoma, SK-HEP-1 cells are frequently utilized as a model system for liver sinusoidal endothelial cells due to their unique dual phenotype. The cells express markers of both endothelial and epithelial lineages, making them suitable for studying liver-specific signaling pathways, metabolic functions, and interactions with circulating peptides. The use of this hepatic background allows context-dependent investigation of GPR75 signaling in a cell type that interfaces with systemic metabolic regulators.
GPR75 functions as a receptor for the cocaine- and amphetamine-regulated transcript (CART) peptide, an anorexigenic neuropeptide involved in appetite suppression and energy expenditure. Upon CART binding, GPR75 couples to heterotrimeric G proteins, including Gs and Gi/o subtypes, leading to modulation of adenylate cyclase activity and subsequent changes in intracellular cAMP levels. This triggers downstream activation of protein kinase A (PKA) and the transcription factor CREB, while also engaging the MAPK/ERK cascade (ERK1/2) to regulate gene expression. Additionally, GPR75 interacts with ??-arrestins, which can mediate receptor desensitization and initiate G protein-independent signaling. Upstream, leptin and insulin are known to influence CART expression and release, thereby indirectly modulating GPR75 activity. In this signaling network, GPR75 acts as a central node in neuropeptide-mediated control of energy balance.
In the SK-HEP-1 hepatic adenocarcinoma background, disruption of GPR75 offers a platform to dissect how CART peptide signaling directly impacts liver cell function. Given the liver’s pivotal role in glucose and lipid metabolism, this knockout model is particularly relevant for exploring the organ-specific contributions of GPR75 to systemic energy homeostasis. The loss of GPR75 may alter cAMP/PKA and ERK1/2 pathway activities, affecting CREB-driven transcriptional programs and potentially impacting processes such as glucose uptake, lipid accumulation, and cell proliferation. Consequently, these polyclonal knockout cells facilitate investigations into whether GPR75 mediates crosstalk between neuroendocrine signals and hepatic metabolic pathways, with implications for obesity, type 2 diabetes, and non-alcoholic fatty liver disease.
Researchers can employ these GPR75 knockout SK-HEP-1 polyclonal cells in a broad range of functional assays. For GPCR signaling analyses, cAMP accumulation assays and calcium flux measurements are well-suited to quantify CART-induced responses. ??-arrestin recruitment assays enable assessment of receptor activation and trafficking. Metabolic phenotyping can be performed via glucose uptake assays and lipid accumulation detection, while RT-qPCR and Western blotting allow monitoring of downstream target expression, including CREB and phospho-ERK1/2. Cell proliferation and migration assays provide insights into GPR75’s role in cellular behavior. These applications support obesity research, metabolic disease modeling, and validation of GPR75 as a therapeutic target. For additional technical information or batch-specific data, please contact Ascent Research.
