TH Knockout Cell Line (HEK293)

Human embryonic kidney (HEK) 293 cells are widely used for recombinant protein production because of their efficient posttranslational modification capabilities. However, their large-scale culture is often limited by metabolic stress and early apoptosis, leading to insufficient protein yields. In this study, we aim to increase protein expression through the coordinated modulation of metabolic and apoptotic pathways. Using CRISPR/Cas9 technology, we target and knockout the genes of ornithine decarboxylase antizyme 1 (OAZ1), which regulates polyamine metabolism, and caspase 8-associated protein 2 (CASP8AP2), an apoptosis-related protein. We successfully construct an / double-knockout HEK293 cell line. Following transfection with the knockout vector and screening of single-cell clones, multiple levels of validation confirm the successful gene knockout. The results show that the double-knockout cells exhibit significantly reduced apoptosis rates. Furthermore, the production of recombinant secreted alkaline phosphatase (SEAP) and vitronectin (VN) increases by 2.1 folds and 2.9 folds, respectively, compared with those in wild-type cells. Metabolic profiling reveals that the cell cycle is arrested in the G1/G0 phase, accompanied by increased specific consumption and production rates of key metabolites. This study demonstrates that concurrent inhibition of apoptosis and optimization of metabolism effectively enhances recombinant protein production in HEK293 cells, suggesting a novel strategy for improving HEK293 cell-based expression.

Tyrosyl-DNA phosphodiesterase 1 (TDP1) is a human DNA repair protein. It is a member of the phospholipase D family based on structural similarity. TDP1 is a key enzyme of the repair of stalled topoisomerase 1 (TOP1)-DNA complexes. Previously, with the CRISPR/Cas9 method, we obtained HEK293A cells with a homozygous knockout of the TDP1 gene and used the TDP1 knockout cells as a cellular model for studying mechanisms of action of an anticancer therapy. In the present work, we hypothesized that the TDP1 knockout would alter the expression of DNA repair-related genes. By transcriptomic analysis, we investigated for the first time the effect of the TDP1 gene knockout on genes' expression changes in the human HEK293A cell line. We obtained original data implying a role of TDP1 in other processes besides the repair of the DNA-TOP1 complex. Differentially expressed gene analysis revealed that TDP1 may participate in cell adhesion and communication, spermatogenesis, mitochondrial function, neurodegeneration, a cytokine response, and the MAPK signaling pathway.