The HPDL Knockout SK-HEP-1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population engineered to disrupt the HPDL gene in a human liver sinusoidal endothelial cell background. This loss-of-function model enables the investigation of HPDL-dependent mitochondrial pathways in a well-characterized endothelial host. The polyclonal format preserves population-level heterogeneity, making it suitable for bulk functional assays where gene disruption is introduced via CRISPR/Cas9-mediated genome editing without clonal selection.
SK-HEP-1 cells are derived from a human liver adenocarcinoma ascites and exhibit a stable endothelial phenotype closely resembling primary liver sinusoidal endothelial cells (LSECs). These cells serve as a tractable in vitro model for studying LSEC biology, including the regulation of hepatic vascular permeability, immune surveillance, and the maintenance of hepatic stellate cell quiescence. Their robust growth and endothelial characteristics make them a useful platform for dissecting metabolic and oxidative stress responses within the liver microenvironment.
HPDL encodes a mitochondrial enzyme with structural homology to 4-hydroxyphenylpyruvate dioxygenase (HPD) and is implicated in tyrosine catabolism and coenzyme Q (CoQ) biosynthesis. Mechanistically, HPDL is thought to catalyze the conversion of 4-hydroxyphenylpyruvate to homogentisate or a distinct step in CoQ assembly, thereby supporting mitochondrial respiratory chain function. Its activity is regulated by upstream factors including PGC-1?? and HIF1??, and it interacts directly with HPD, other CoQ biosynthetic enzymes, and mitochondrial complex I subunits. Disruption of HPDL leads to reduced mitochondrial complex I activity, elevated reactive oxygen species production, and decreased coenzyme Q10 levels, highlighting its role in maintaining redox homeostasis and oxidative phosphorylation.
In the SK-HEP-1 LSEC context, HPDL knockout provides a unique tool to dissect the intersection between mitochondrial metabolism and endothelial function. Loss of HPDL is expected to impair mitochondrial respiration and increase oxidative stress, which may compromise endothelial barrier integrity, migration, and angiogenic potential. This model is particularly relevant for studying how metabolic dysfunction in LSECs contributes to hepatic vascular disease and for exploring the hepatic aspects of HPDL-related neurological disorders, as the enzyme’s fundamental role in CoQ biosynthesis is conserved across tissues.
Key research applications include mechanistic studies of tyrosine catabolism and CoQ biosynthesis in liver endothelial cells, functional assessment of mitochondrial respiration using Seahorse analysis, quantification of coenzyme Q10 by LC-MS, and evaluation of oxidative stress via DCFDA or MitoTracker staining. The knockout population can be employed in wound healing and tube formation assays to examine endothelial dysfunction under metabolic stress, and in flow cytometry for mitochondrial membrane potential (TMRE). Validation of HPDL disruption can be performed by western blotting or RT-qPCR. For technical inquiries, please contact Ascent Research.
