Modeling apoptosis resistance in CHO cells with CRISPR-mediated knockouts of Bak1, Bax, and Bok

Chinese hamster ovary (CHO) cells are the primary platform for the production of biopharmaceuticals. To increase yields, many CHO cell lines have been genetically engineered to resist cell death. However, the kinetics that governs cell fate in bioreactors are confounded by many variables associated with batch processes. Here, we used CRISPR‐Cas9 to create combinatorial knockouts of the three known BCL‐2 family effector proteins: Bak1, Bax, and Bok. To assess the response to apoptotic stimuli, cell lines were cultured in the presence of four cytotoxic compounds with different mechanisms of action. A population‐based model was developed to describe the behavior of the resulting viable cell dynamics as a function of genotype and treatment. Our results validated the synergistic antiapoptotic nature of Bak1 and Bax, while the deletion of Bok had no significant impact. Importantly, the uniform application of apoptotic stresses permitted direct observation and quantification of a delay in the onset of cell death through Bayesian inference of meaningful model parameters. In addition to the classical death rate, a delay function was found to be essential in the accurate modeling of the cell death response. These findings represent an important bridge between cell line engineering strategies and biological modeling in a bioprocess context

Recent Advances in Synthesis of Metal-Carbon Nanocomposites and Their Application in Catalytic Hydrogenation Reactions

Carbon materials such as activated carbon, carbon nanotubes, carbon nanofibers, fullerenes, and graphene are used as support for heterogeneous catalysis because of their large specific surface area, good porosity, high electron conductivity, and relative chemical inertness. The composition of these materials with metal nanoparticles has attracted huge attention in catalytic hydrogenation because of their excellent electrical, thermal, optical, and mechanical properties as well as high surface-to-volume ratios. Specifically, metal-carbon nanotube-based nanocomposite has demonstrated extraordinary catalytic activity in hydrogenation reaction by virtue of the integration and synergetic effects between both materials. Highly valuable products applicable for pharmaceutical, biomedical, and agricultural industries are produced from the catalytic hydrogenation reactions. Consequently, the demand for metal nanocomposites has been increasing rapidly, and particular attention is required for advanced synthesis techniques and to understand the real factors responsible for high catalytic activity. This chapter includes the significant advances that have emerged in this field and aims to explore the catalytic-activity-dependent factors and their prospective application in the hydrogenation reaction