Bacteria: An Unexpected Key to Curing Deadly Disease?
Scientists at the University of California in San Francisco have been studying clustered regularly interspaced short palindromic repeats, or CRISPRs for short, in prokaryotic (single-celled) organisms such as bacteria.
It's extremely good at two things: spreading terrifyingly fast throughout the body, and threading little needles of fear through every patient's heart. Billions of dollars have been funneled into researching newer, cheaper, more effective ways to combat the second greatest cause of death in the United States, yet those affected still suffer through chemotherapy and radiation treatments year after year. What if I told you that some of our nation's brightest have been researching what they believe will become an effective cure not only to cancer, but to a plethora of autoimmune diseases like HIV, multiple sclerosis, and rheumatoid arthritis?
It's reality. Scientists at the University of California in San Francisco have been studying clustered regularly interspaced short palindromic repeats, or CRISPRs for short, in prokaryotic (single-celled) organisms such as bacteria. These genetic sequences are part of the single-celled organisms' defense against invading viruses.
In the CRISPR system, as this defense is known, the bacteria recognizes foreign viruses that destroy the bacteria by altering its genetic code, and cuts the altered segments out of its DNA. By understanding how the CRISPR system works in bacteria, the UCSF scientists have been able to apply this natural defense to possible treatments of human diseases like cancer and autoimmune disorders.
This process is carried out with the help of an enzyme, a protein in the body that helps carry out reactions. That enzyme, called Cas9, acts like molecular scissors as part of the CRISPR system (or the CRISPR/Cas9 complex, as it is known) and performs the actual cutting of the unwanted DNA.
So, how does this apply to humans, and how is it revolutionizing medicine?
Imagine a patient with cancer: The malignant cells spread in the body, weakening the immune system. T cells, a type of white blood cell that tracks down and kills "invaders" (like cancer), destroy some cancer cells but are often overwhelmed by the reduced number of white blood cells in a cancer-affected body.
With the CRISPR/Cas9 complex, though, scientists can now remove T cells from a patient and "edit" the DNA. This means that they use the Cas9 enzyme to splice part of the DNA, like bacteria do, but in this case, they insert another piece of genetic material that "turns off" a protein called PD-1. Turning off PD-1 has been shown to cause T cells to attack cancer cells more vigorously. Thus, in the instance of the cancer patient, the CRISPR/Cas9 complex allows them to better fight off the disease.
Let's look at the applications to the 14-22 million patients in the United States suffering from autoimmune diseases. The "editing process" for a patient with HIV, for example, involves disabling a specific protein called CXCR4, preventing the HIV virus from taking advantage of T cells so easily.
These proteins were successfully blocked in about a third of the manipulated T cells. Extracted from patients individually, the T cells must be edited for each person and then inserted back into the body to produce these encouraging results. As of yet, scientists have not been able to cause T cells to reproduce in the body, but they hope to achieve this in the future.
For people with a diagnoses of cancer, multiple sclerosis, or countless autoimmune diseases, it can sound like a death sentence and a one-way ticket to a long, drawn-out fight. With this newly engineered technology, however, inspired by a natural process from the tiniest of organisms, there's hope for the future. Although single-celled and wholly unimpressive, tiny prokaryotes have provided a possible solution to some of modern medicine's biggest problems.
- Ossola, Alexandra. "Scientists Tweak T Cells Using CRISPR." Popular Science. N.p., 28 July 2015. Web. 31 July 2015.
- "TransEDIT CRISPR Cas9 for Genome Editing." Crispr Cas9 Genome Editing, Crispr Design, Gene Editing. N.p., n.d. Web. 31 July 2015.
- "Autoimmunity, Autoimmune Diseases." SpringerReference (2011): n. pag. US Department of Health and Human Services. Web. 31 July 2015.