In the scientific field of protein study, the ability to actually purify and collect a protein of interest is the very first obstacle to overcome. In that endeavor, recent work by Hopkins researchers in the Department of Chemical and Biomolecular Engineering has shed light on one area of improving protein yields: cell apoptosis, a pathway which ultimately leads to cell death.
Cell apoptosis is essentially programmed cell death, a mechanism in which the cell actively starts a pathway to kill itself. Several factors include limited nutrients, accumulation of toxins and growth factor withdrawal. Furthermore, in bioreactors (engineered devices that support and host cells), cell apoptosis is the leading cause of cell death.
In the case of protein study, cells can be engineered to produce a protein of interest. However, within the laboratory, cell death ultimately leads to reduced yields of protein. Tying both concepts together, with the knowledge that cell apoptosis causes most cell deaths and that cell deaths lead to less protein, it makes sense that any mechanism to reduce apoptosis would then lead to increased protein production. That is where the research comes in.
To counteract this pesky problem of apoptosis, the Hopkins team investigated methods of making cells resistant to apoptosis through genetic modification. In one case, several proteins such as the Bcl-XL have shown antiapoptotic behavior when they were overexpressed in mammalian cells, hence offering a method of increasing cell life span. However, the researchers did find that by overexpressing the protein through genetic modification, the cell also lost some ability to produce the actual protein of interest. As a result, any use of gene modification to achieve optimal results would be a balance between increased cell life and decreased cell productivity.
The efforts towards increasing antiapoptotic protein production were explained in the study as having several steps. First, the cell would have to be infected with the gene through some sort of transfection mechanism, a means of introducing nucleic acids into a cell. Second, a promoter would have to be incorporated to allow for sufficient expression of the antiapoptotic gene. Finally, the cell culture would have to be tested to ensure that both the antiapoptotic protein and the protein of interest were being synthesized.
In the study, after carrying out a series of steps to ensure a line of apoptotic resistant cells had been produced, the researchers compared the protein yields of this line with the yields from a normal cell culture. As expected, the yield from the apoptotic resistant cells turned out to be about 150 percent more than that of the nonresistant cells.
The use of this new mechanism for protein study reaches as far into science as one could imagine. Because proteins play such vital roles in the human body, the ability to understand their structure and function has been an area of interest for scientists in recent years. Furthermore, many drugs have their basis in protein activity, so by adding yet another tool to aid in protein study, Hopkins researchers are advancing not only general knowledge, but also the real world application for furthering healthcare.
