Little scientific news has come along in recent years to rival the headlines for CRISPR/Cas9, a powerful new gene-editing tool with unprecedented implications for the future of medicine, agriculture, energy and, indeed, humanity.
Already among the biggest science stories of the decade, CRISPR, as it is commonly called, essentially harnesses the immune system of bacteria to edit genes in other organisms; that is, in plants, animals and people. While gene-editing tools have existed for years, CRISPR’s potential for deleting undesirable traits and adding desirable traits is far greater than anything else to date.
In brief, CRISPR got its start in 1987 when Japanese scientists studying E. coli noticed unusual repeating sequences in the bacteria’s DNA. Twenty years later, food scientists studying yogurt bacteria determined that these “odd clusters” were actually part of the bacteria’s immune system – the bacteria produced a special attack enzyme known as Cas9 to chop up the attacker’s DNA and neutralize the threat. Thus CRISPR, or Clustered Regularly Interspaced Short Palindromic Repeats, as a gene-editing tool was born.
What makes CRISPR so revolutionary is its ability to perform near-perfect edits more quickly, easily, precisely and, yes, cheaply, than ever before. What once took weeks or months can now be done in hours; and the high costs of gene editing have dropped to a fraction of the price.
CRISPR’s impact on medicine will likely be enormous. Already, it has been shown to edit bone marrow cells in mice to treat sickle-cell anemia. Researchers are now exploring its use in destroying DNA viruses such as HIV, herpes, HPV and hepatitis. CRISPR might even stop such genetic diseases as Huntington’s disease or cystic fibrosis, and could be the essential tool in one day creating powerful and much-needed new antibiotics.
And then there is CRISPR’s potential in vaccine development. While pharma scientists have long used bacteria, yeast and mammal cells to develop vaccines, they are now looking to plants or plant cells to help with “molecular pharming.” CRISPR could help precisely insert specific genes into plants, allowing researchers to study how plant genes are regulated, how they respond to foreign molecules and how they repair their DNA. Such new knowledge could lead to vaccines that have been difficult to develop and manufacture.
“Genetic vaccinations” hold great promise – along with some concern -- for the future. For example, CRISPR might help modify certain genes to prevent the HIV virus from attacking the immune system. But while HIV might be effectively cured, modifying those genes to resist HIV could increase susceptibility to West Nile virus. And despite its precision, CRISPR is not perfect; for example, Cas9 enzymes might cut DNA in the wrong place and cause unexpected and unwanted results.
There are many concerns about human testing, of course, especially until proper standards can be developed. And there are profound ethical questions about which genes should be edited, or whether we should be editing genes at all. While we may be able to deepen our understanding of the human genome, and develop important new therapies, does this open the way to humans being engineered with specific genetic traits?
With CRISPR’s ability to transform medicine – and life as we know it – cautious optimism might be the best key phrase of the day.