Metabolomics, the global, unbiased profiling of biochemicals in a complex system, looks at the widest possible range of pathways
in a system to detect changes during cell growth related to the medium, feeding, or temperature shifts. By using metabolomics
to understand the action of biochemicals present in a cell system, process development researchers can discover targets for
pathway engineering, enhance the development and optimization of growth media, and refine the scale-up process. The technology
also can be used to identify the critical quality attributes of a process in a Quality-by-Design approach to process development,
or for later application of process analytical technology for ongoing process monitoring.
Identifying relevant biochemical markers in cell line selection and growth media development has traditionally been conducted
using processes that are largely based on a trial-and-error methodology. Conventional approaches can be very costly, time-consuming,
and ultimately frustrating for the researcher. A tool called metabolomics uses global biochemical analysis to gain mechanistic
insight into biochemical and metabolite changes in cell systems and media, and greatly increases the speed with which process
development researchers can find relevant biomarkers for optimizing their processes for more meaningful results.
Historically, process development researchers have relied on a limited number of metabolites (such as lactate, ammonia, and
glucose) to provide insight into the metabolic state of a cell and the performance of the culture in the bioreactor. Improvements
in productivity and quality of results have been the target measurements. Even in the era of genomics, metabolites and phenotypic
data (e.g., titer) are the principal benchmarks by which cell culture and process development scientists determine the success
or failure of an experiment. Although scientists understand the powerful connections between metabolites and phenotype, the
inability to study more than a few metabolites at a time has proven a severely limiting factor in advancing research.
Using Metabolomics to Understand Cellular Phenotype
Small-molecule metabolites are the end products of cellular processes, and are considered the most accurate markers of how
biological systems respond to genetic or environmental changes. Thus, biochemicals (metabolites) are the key to cellular phenotypes.
There are approximately 2,900 biochemicals in the mammalian metabolome. Unlike macromolecules, metabolites represent focused,
distilled changes in phenotype.
Scientists developing a recombinant protein process typically look at about five metabolites during an experiment. Whether
or not those particular metabolites are significant is not known until the experiment has run its course. The bias shown toward
metabolites whose behaviors are chosen for observation during the experiment often excludes potentially relevant markers while
generating little useful data. Thus, many iterations of an experiment can be conducted without identifying genuinely significant
Metabolomics, the global, unbiased profiling of biochemicals in a complex system, looks at the widest range of pathways in
an experimental system for significant changes that occur during cell growth in a particular medium as well as in response
to feeding or temperature shifts. This approach maximizes the chances for determining the relevant pathways associated with
a poor product quality or a metabolic switch. In addition, the biochemical markers associated with the pathway can be used
for further development and, eventually, in production.