CRISPR-Act 3.0 could significantly increase crop yields and plant diversity worldwide and help fight against global hunger and climate change
Clinical laboratory professionals and pathologists who read Dark Daily are highly aware of CRISPR gene editing technology. We’ve covered the topic in multiple ebriefings over many years. But how many know there’s a version of CRISPR specifically designed for editing and activating plant genes?
Scientists at the University of Maryland (UMD) developed a new version of CRISPRa (CRISPR Activation) for plants which they claim has four to six times the activation capacity of currently available CRISPRa systems and can activate up to seven genes at once. They call their new and improved CRISPRa technology “CRISPR-Act 3.0.”
CRISPR-Act 3.0 Increases Function of Multiple Genes Simultaneously
The UMD researchers successfully applied CRISPR-Act 3.0 technology to activate many types of genes in plants, including the ability to expedite the breeding process via faster flowering. They hope that activating genes in plants to improve functionality will result in better plants and crops.
“Through activation, you can really uplift pathways or enhance existing capacity, even achieve a novel function. Instead of shutting things down, you can take advantage of the functionality already there in the genome and enhance what you know is useful,” said Yiping Qi, PhD, associate professor, Department of Plant Science and Landscape Architecture at the University of Maryland, in a UMD new release.
The scientists also noted that there may be other advantages to this type of multiplexed activation of genes.
“Having a much more streamlined process for multiplexed activation can provide significant breakthroughs. For example, we look forward to using this technology to screen the genome more effectively and efficiently for genes that can help in the fight against climate change and global hunger,” Qi added. “We can design, tailor, and track gene activation with this new system on a larger scale to screen for genes of importance, and that will be very enabling for discovery and translational science in plants.”
The researchers hope this technology can have a major impact on the efficiency of crop and food production.
“This type of technology helps increase crop yield and sustainably feed a growing population in a changing world,” Qi said. “I am very pleased to continue to expand the impacts of CRISPR technologies.”
Feeding the World’s Hungry with CRISPR
CRISPR is a robust tool used for editing genomes that typically operates as “molecular scissors” to cut DNA. CRISPR-Act 3.0, however, uses deactivated CRISPR-Cas9 which can only bind and not cut. This allows the system to work on the activation of proteins for designated genes of interest by binding to certain segments of DNA. The UMD researchers believe there is significant potential for expanding the multiplexed activation further, which could alter and improve genome engineering.
“People always talk about how individuals have potential if you can nurture and promote their natural talents,” Qi said in the UMD news release. “This technology is exciting to me because we are promoting the same thing in plants—how can you promote their potential to help plants do more with their natural capabilities? That is what multiplexed gene activation can do, and it gives us so many new opportunities for crop breeding and enhancement.”
CRISPR is being developed and enhanced in many research settings, and knowledge of how to best use the gene editing technology is rapidly advancing. Though more research on CRISPR-Act 3.0 is needed to ensure its reliability, it’s exciting to consider the potential of gene activation for massively increasing crop yield worldwide.
Not to mention how new CRISPR technologies continue to drive innovations in clinical laboratory diagnostics and precision medicine treatments.
CRISPR-Cas9 connection to cancer prompts research to investigate different approaches to gene editing
Dark Daily has covered CRISPR-Cas9 many times in previous e-briefings. Since its discovery, CRISPR, or Clustered Regularly Interspaced Short Palindromic Repeats, has been at the root of astonishing breakthroughs in genetic research. It appears to fulfill precision medicine goals for patients with conditions caused by genetic mutations and has anatomic pathologists, along with the entire scientific world, abuzz with the possibilities such a tool could bring to diagnostic medicine.
All of this research has contributed to a deeper understanding of how cells function. However, as is often the case with new technologies, unforeseen and problematic questions also have arisen.
“Here we report significant on-target mutagenesis, such as large deletions and more complex genomic rearrangements at the targeted sites in mouse embryonic stem cells, mouse hematopoietic progenitors, and a human differentiated cell line,” wrote the authors in their introduction.
Another study, this one conducted by biomedical researches at Cambridge, Mass., and published in Nature, describes possible toxicity caused by Cas9.
“Our results indicate that Cas9 toxicity creates an obstacle to the high-throughput use of CRISPR-Cas9 for genome engineering and screening in hPSCs [human pluripotent stem cells]. Moreover, as hPSCs can acquire P53 mutations, cell replacement therapies using CRISPR-Cas9-enginereed hPSCs should proceed with caution, and such engineered hPSCs should be monitored for P53 function.”
Essentially what both groups of researchers found is that CRISPR-Cas9 cuts through the double helix of DNA, which the cell responds to as it would any injury. A gene called p53 then directs a cellular “first-aid kit” to the “injury” site that either initiates self-destruction of the cell or repairs the DNA.
Therefore, in some instances, CRISPR-Cas9 is inefficient because the repaired cells continue to function. And, the repair process involves the p53 gene. P53 mutations have been implicated in ovarian, colorectal, lung, pancreatic, stomach, liver, and breast cancers.
Though important, some experts are downplaying the significance of the findings.
Erik Sontheimer, PhD (above), Professor, RNA Therapeutics Institute, at the University of Massachusetts Medical School, told Scientific American that the two studies are important, but not show-stoppers. “This is something that bears paying attention to, but I don’t think it’s a deal-breaker,” he said. (Photo copyright: University of Massachusetts.)
“It’s something we need to pay attention to, especially as CRISPR expands to more diseases. We need to do the work and make sure edited cells returned to patients don’t become cancerous,” Sam Kulkarni, PhD, CEO of CRISPR Therapeutics, told Scientific American.
Both studies are preliminary. The implications, however, is in how genes that have become corrupted are used.
A team from the Salk Institute may have found a solution. They are investigating a different enzyme—Cas13d—which, in conjunction with CRISPR would target RNA rather than DNA. “DNA is constant, but what’s always changing are the RNA messages that are copied from the DNA. Being able to modulate those messages by directly controlling the RNA has important implications for influencing a cell’s fate,” Silvana Konermann, PhD, a Howard Hughes Medical Institute (HHMI) Hanna Gray Fellow and member of the research team at Salk, said in a news release.
The Salk team published their findings in the journal Cell. The paper describes how “scientists from the Salk Institute are reporting for the first time the detailed molecular structure of CRISPR-Cas13d, a promising enzyme for emerging RNA-editing technology. They were able to visualize the enzyme thanks to cryo-electron microscopy (cryo-EM), a cutting-edge technology that enables researchers to capture the structure of complex molecules in unprecedented detail.”
The researchers think that CRISPR-Cas13d may be a way to make the process of gene editing more effective and allow for new strategies to emerge. Much like how CRISPR-Cas9 led to research into recording a cell’s history and to tools like SHERLOCK (Specific High-sensitivity Enzymatic Reporter unLOCKing), a new diagnostic tool that works with CRISPR and changed clinical laboratory diagnostics in a foundational way.
Each discovery will lead to more branches of inquiry and, hopefully, someday it will be possible to cure conditions like sickle cell anemia, dementia, and cystic fibrosis. Given the high expectations that CRISPR and related technologies can eventually be used to treat patients, pathologists and medical laboratory professionals will want to stay informed about future developments.
Recording Complex Biological Events in the Genomes of Bacteria
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) are DNA sequences containing short, repetitive base sequences found in the genomes of bacteria and other micro-organisms that can facilitate the modification of genes within organisms. The term CRISPR also can refer to the whole CRISPR-Cas9 system, which can be programmed to pinpoint certain areas of genetic code and to modify DNA at exact locations.
“As promising as this was, we did not know what would happen when we tried to track about 100 sequences at once, or if it would work at all,” noted Seth Shipman, PhD, Postdoctoral Fellow, and one of the authors of the study in the Harvard Gazette story. “This was critical since we are aiming to use this system to record complex biological events as our ultimate goal.”
Translating Digital Information into DNA Code
The team transferred an image of a human hand and five frames of a movie of a running horse onto nucleotides to imbed data into the genomes of bacteria. This produced a code relating to the pixels of each image. CRISPR was then used to insert genetic code into the DNA of Escherichia coli (E-coli) bacteria. The researchers discovered that CRISPR did have the ability to encode complex information into living cells.
“The information is not contained in a single cell, so each individual cell may only see certain bits or pieces of the movie. So, what we had to do was reconstruct the whole movie from the different pieces,” stated Shipman in a BBC News article. “Maybe a single cell saw a few pixels from frame one and a few pixels from frame four … so we had to look at the relation of all those pieces of information in the genomes of these living cells and say, ‘Can we reconstruct the entire movie over time?’”
The team used an image of a digitized human hand because it embodies the type of intricate data they wish to use in future experiments. A movie also was used because it has a timing component, which could prove to be beneficial in understanding how a cell and its environment may change over time. The researchers chose one of the first motion pictures ever recorded—moving images of a galloping horse by Eadweard Muybridge, a British photographer and inventor from the late 19th century.
“We designed strategies that essentially translate the digital information contained in each pixel of an image or frame, as well as the frame number, into a DNA code that, with additional sequences, is incorporated into spacers. Each frame thus becomes a collection of spacers,” Shipman explained in the Harvard Gazette story. “We then provided spacer collections for consecutive frames chronologically to a population of bacteria which, using Cas1/Cas2 activity, added them to the CRISPR arrays in their genomes. And after retrieving all arrays again from the bacterial population by DNA sequencing, we finally were able to reconstruct all frames of the galloping horse movie and the order they appeared in.”
In the video above, Wyss Institute and Harvard Medical School researchers George Church, PhD, and Seth Shipman, PhD, explain how they engineered a new CRISPR system-based technology that enables the chronological recording of digital information, like that representing still and moving images, in living bacteria. Click on the image above to view the video. It is still too early to determine how this technology may be useful to pathologists and clinical laboratory scientists. (Caption and video copyright: Wyss Institute at Harvard University.)
“In this study, we show that two proteins of the CRISPR system, Cas1 and Cas2, that we have engineered into a molecular recording tool, together with new understanding of the sequence requirements for optimal spacers, enables a significantly scaled-up potential for acquiring memories and depositing them in the genome as information that can be provided by researchers from the outside, or that, in the future, could be formed from the cells natural experiences,” stated Church in the Harvard Gazette story. “Harnessed further, this approach could present a way to cue different types of living cells in their natural tissue environments into recording the formative changes they are undergoing into a synthetically created memory hotspot in their genomes.”
Encoding Information into Cells for Clinical Laboratory Testing and Therapy
The team plans to focus on creating molecular recording devices for other cell types and on enhancing their current CRISPR recorder to memorize biological information.
“One day, we may be able to follow all the developmental decisions that a differentiating neuron is taking from an early stem cell to a highly-specialized type of cell in the brain, leading to a better understanding of how basic biological and developmental processes are choreographed,” stated Shipman in the Harvard Gazette story. Ultimately, the approach could lead to better methods for generating cells for regenerative therapy, disease modeling, drug testing, and clinical laboratory testing.
According to Shipman in the BBC News article, these cells could “encode information about what’s going on in the cell and what’s going on in the cell environment by writing that information into their own genome.”
This field of research is still new and its full potential is not yet understood. However, if this capability can be developed, there could be opportunities for pathologists and molecular chemists to develop methods for in vivo monitoring of a patient’s cell function. These methods could prove to be an unexpected new way for clinical laboratories to add value and become more engaged with the clinical care team.
Unlike most other CRISPR/Cas-9 therapies that are ex vivo treatments in which cells are modified outside the body, this study was successful with an in vivo treatment
Use of CRISPR-Cas9 gene editing technology for therapeutic purposes can be a boon for clinical laboratories. Not only is this application a step forward in the march toward precision medicine, but it can give clinical labs the essential role of sequencing a patient’s DNA to help the referring physician identify how CRISPR-Cas9 can be used to edit the patient’s DNA to treat specific health conditions.
Most pathologists and medical lab managers know that CRISPR-Cas9 gene editing technology has been touted as one of the most significant advances in the development of therapies for inherited genetic diseases and other conditions. Now, a pair of biotech companies have announced a milestone for CRISPR-Cas9 with early clinical data involving a treatment delivered intravenously (in vivo).
As with other therapies, determining which patients are suitable candidates for specific treatments is key to the therapy’s success. Therefore, clinical laboratories will play a critical role in identifying those patients who would most likely benefit from a CRISPR-delivered therapy.
Such is the goal of precision medicine. As methods are refined that can correct unwelcome genetic mutations in a patient, the need to do genetic testing to identify and diagnose whether a patient has a specific gene mutation associated with a specific disease will increase.
Cleveland Clinic describes ATTR amyloidosis as a “protein misfolding disorder” involving transthyretin (TTR), a protein made in the liver. The disease leads to deposits of the protein in the heart, nerves, or other organs.
According to Intellia and Regeneron, NTLA-2001 is designed to inactivate the gene that produces the protein.
The interim clinical trial data indicated that one 0.3 mg per kilogram dose of the therapy reduced serum TTR by an average of 87% at day 28. A smaller dose of 0.1 mg per kilogram reduced TTR by an average of 52%. The researchers reported “few adverse events” in the six study patients, “and those that did occur were mild in grade.”
Current treatments, the companies stated, must be administered regularly and typically reduce TTR by about 80%.
“These are the first ever clinical data suggesting that we can precisely edit target cells within the body to treat genetic disease with a single intravenous infusion of CRISPR,” said Intellia President and CEO John Leonard, MD, in a press release. “The interim results support our belief that NTLA-2001 has the potential to halt and reverse the devastating complications of ATTR amyloidosis with a single dose.”
He added that “solving the challenge of targeted delivery of CRISPR-Cas9 to the liver, as we have with NTLA-2001, also unlocks the door to treating a wide array of other genetic diseases with our modular platform, and we intend to move quickly to advance and expand our pipeline.”
In Part 2 of the Phase 1 trial, Intellia plans to evaluate the new therapy at higher doses. After the trial is complete, “the company plans to move to pivotal studies for both polyneuropathy and cardiomyopathy manifestations of ATTR amyloidosis,” the press release states.
Previous clinical trials reported results for ex vivo treatments in which cells were removed from the body, modified with CRISPR-Cas9 techniques, and then reinfused. “But to be able to edit genes directly in the body would open the door to treating a wider range of diseases,” Nature reported.
How CRISPR-Cas9 Works
On its website, CRISPR Therapeutics, a company co-founded by Emmanuelle Charpentier, PhD, a director at the Max Planck Institute for Infection Biology in Berlin, and inventor of CRISPR-Cas9 gene editing, explained that the technology “edits genes by precisely cutting DNA and then letting natural DNA repair processes take over.” It can remove fragments of DNA responsible for causing diseases, as well as repairing damaged genes or inserting new ones.
The therapies have two components: Cas9, an enzyme that cuts the DNA, and Guide RNA (gRNA), which specifies where the DNA should be cut.
Charpentier and biochemist Jennifer Doudna, PhD, Nobel Laureate, Professor of Chemistry, Professor of Biochemistry and Molecular Biology, and Li Ka Shing Chancellor’s Professor in Biomedical and Health at the University of California Berkeley, received the 2020 Nobel Prize in Chemistry for their work on CRISPR-Cas9, STAT reported.
At some future point, it can be expected that these technologies will be combined and integrated in a way that allows clinical laboratories to make very early and accurate diagnoses of many health conditions.
U.S. Patent and Trademark Office will hold hearings to determine whether University of California Berkeley, or Broad Institute of Harvard and MIT, should receive patents for new genomic engineering technique
In the race to master gene-editing in ways that will advance genetic medicine and patient care, one of the hottest technologies is CRISPR, which stands for Clustered Regularly Interspaced Short Palindromic Repeats. But now a patent fight has the potential to complicate how pathologists and other scientists use this exciting technology.
This dispute over the CRISPR patent—a tool that has been hailed as one of the biggest biotech breakthroughs of the decade—will likely be settled in the coming months by the United States Patent and Trademark Office (USPTO).