What’s All The Buzz About CRISPR?

It’s inevitable— genetics is the future of medicine. With the discovery of certain diseases linked to specific gene mutations, the science community became engrossed in DNA manipulation. Precisely, CRISPR gained global recognition in the past few years as a promising therapeutic strategy in human genetic diseases. CRISPR could provide a means to directly alter mutations that underlie single-gene disorders such as cystic fibrosis or more complex diseases such as cancer.

So, what is the mechanism behind this novel genome editing technique? “CRISPR,” an acronym for Clustered Regularly Interspaced Short Palindromic Repeats, is part of the bacterial adaptive immune system to combat invading viruses. In short, these DNA segments or CRISPR arrays are created upon the first invasion as a means for the bacteria to “remember” the virus. Upon subsequent attacks, the bacteria can then transcribe RNA segments from the CRISPR arrays to direct enzymes such as Cas9 to a target sequence of the viruses’ DNA. Cas9 or a similar nuclease can then cut the DNA and kill the virus.

Just five years ago, the CRISPR-Cas9 system was utilized for the first time in a laboratory setting. In January 2013, the Zhang lab published CRISPR-Cas9 as a genome modification tool in eukaryotic cells (Cong et al., 2013). In the same way as the bacterial defense system, researchers can generate RNA sequences that attach to specific target locations of DNA. These small pieces of RNA also bind to Cas9 or Cpf1 to cut the desired DNA sequence. In effect, the cell’s DNA repair machinery can then add, delete, or make changes to the genetic material. Researchers are currently investigating the effectiveness of CRISPR-Cas9 in the treatment of cystic fibrosis, hemophilia, and sickle cell disease in human and mouse cells as well as animal models. In addition, this therapy holds promise for complex or multifactorial disorders such as cancer, heart disease, mental illness, and human immunodeficiency virus (HIV).

The big question is whether CRISPR could potentially be used in the prevention and treatment of human disease. However, there are several hurdles to be overcome before this genome editing tool can be experimented on human subjects. Along with safety, specificity, and overall efficacy concerns, ethical issues also arise when dealing with genome editing using CRISPR-Cas9. In contrast with somatic cell DNA manipulation, changes made to DNA in germ-line cells and embryos could be passed down to future generations as well as introduce several ethical deliberations. Some of these include whether genetic engineering would encompass sexual and cosmetic selection in addition to clinical gene therapy. In other words, a somewhat science fiction concept of genetically engineering “designer babies” could become a reality. Regulation surrounding CRISPR-Cas9 system is a new challenge due to its simple creation and low cost for genome modification.

Altogether, CRISPR is a cutting-edge biotechnology innovation that has the potential to dramatically change our approach to disease treatment and prevention and improve both the span of our lives and quality of life. Can you imagine having the ability to change what is written in your or your child’s biological code to evade debilitating diseases such as Tay-Sachs or Huntington’s disease? With the rapid advances of CRISPR technology, current obstacles that stand in the way of human gene therapy will soon be a trouble of the past.

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Elizabeth Arruda

Is a contributor to The Almost Doctor’s Channel.