Crispr Can Edit Directly Genes Inside Human Bodies

A decade ago, biologists Jennifer Doudna and Emmanuelle Charpentier published a landmark paper describing a natural immune system found in bacteria and its potential as a tool for editing the genes of living organisms. A year later, in 2013, Feng Zhang and his colleagues at the Broad Institute of MIT and Harvard reported that they’d harnessed that systemknown as Crispr, to edit human and animal cells in the lab. The work by both teams led to an explosion of interest in using Crispr to treat genetic diseases, as well as a 2020 Nobel Prize for Doudna and Charpentier.

Many diseases arise from gene mutations, so if Crispr could just snip out or replace an abnormal gene, it could in theory correct the disease. But one of the challenges of turning test tube Crispr discoveries into cures for patients has been figuring ouhow to get the gene-editing components to the place in the body that needs treatment.

One biotech company, Crispr Therapeutics, has gotten around that issue by editing patients’ cells outside the body. Scientists there have used the tool to treat dozens of people with sickle cell anemia and beta thalassemia—two common blood disorders. In those trials, investigators extract patients’ red blood cells, edit them to correct a disease-causing mutation, then infuse them back into the body.

But this “ex vivo” approach has downsides. It’s complex to administer, expensive, and has limited uses. Most diseases occur in cells and tissues that can’t be easily taken out of the body, treated, and put back in. So the next wave of Crispr research is focused on editingin vivo”—that is, directly inside a patient’s body. Last year, Intellia Therapeutics was the first to demonstrate that this was possible for a disease called transthyretin amyloidosis. And last week, the Cambridge, Massachusetts-based biotech company showed in-the-body editing in a second disease.


CRISPR Treatment Cuts Cholesterol by Up to 57% in a Single Shot

Scientists have improved upon a form of gene-editing therapy, creating an experimental treatment that looks to hold great promise for treating high cholesterol – a diagnosis affecting tens of millions of Americans, and linked to a number serious health complications. In new research conducted with mice, researchers used an injection of a newly-formulated lipid nanoparticle to deliver CRISPR-Cas9 genome editing components to living animals, with a single shot of the treatment reducing levels of low-density lipoprotein (LDL) cholesterol by up to 56.8 percent. In contrast, an existing FDA-approved lipid nanoparticle (or LNP; a tiny, biodegradable fat capsule) delivery system could only manage to reduce LDLs by 15.7 percent in testing. Of course, these results have so far only been demonstrated in mice, so the new therapy will take a lot of further testing before we know it’s both safe and equally effective in humans. But based on these results so far, signs are promising.

The way the treatment works relates to a gene in humans called Angiopoietin-like 3 (Angptl3), which produces proteins that inhibit the breakdown of certain fats in the bloodstream. People with a mutation in this gene tend to have lower amounts of fatty triglycerides and cholesterol in their blood – without showing other kinds of health complications – and for years scientists have been trying to recreate the process, with treatments that effectively mimic the effects of the mutation.

If we can replicate that condition by knocking out the Angptl3 gene in others, we have a good chance of having a safe and long term solution to high cholesterol,” says biomedical engineer Qiaobing Xu from Tufts University. “We just have to make sure we deliver the gene editing package specifically to the liver so as not to create unwanted side effects.

In the new research, Xu’s team developed a new formulation of LNPs called 306-O12B to target the gene, producing therapeutic effects in wild-type C57BL/6 mice that lasted at stable levels for 100 days after just a single injection of the treatment.

In addition to the cholesterol reduction, the experiment produced a 29.4 percent decrease in triglycerides in the animals’ blood, whereas the FDA-approved delivery method showed only a 16.3 percent reduction.

The findings are reported in PNAS.

New Variant of SARS-CoV-2 Spreading Fast

A coronavirus variant called B1525 has become one of the most recent additions to the global variant watch list and has been included in the list of variants under investigation by Public Health England.

Scientists are keeping a watchful eye on this variant because it has several mutations in the gene that makes the spike protein – the part of the virus that latches onto human cells. These changes include the presence of the increasingly well-known mutation called E484K, which allows the virus to partly evade the immune system, and is found in the variants first identified in South Africa (B1351) and Brazil (P1).

While there is no information on what this means for B1525, there is growing evidence that E484K may impact how effective COVID vaccines are. But there is no suggestion so far that B1525 is more transmissible or that it leads to more severe disease.

There are other mutations in B1525 that are also noteworthy, such as Q677H. Scientists have repeatedly detected this changeat least six times in different lineages in the US, suggesting that it gives the virus an advantage, although the nature of any benefit has not been identified yet.

The B1525 variant also has several deletions – where “letters” (G, U, A and C) of the virus’s RNA are missing from its genome. These letters are also missing in B117, the variant first detected in Kent, England. Research by Ravindra Gupta, a clinical microbiologist at the University of Cambridge, found that these deletions may increase infectivity twofold in laboratory experiments.

As with many variants, B1525 appears to have emerged quite recently. The earliest example in the shared global database of coronavirus genomes, called Gisaid, dates from 15 December 2020. It was identified in a person in the UK. And like many variants, B1525 had already travelled the world before it came to global attention. A total of 204 sequences of this variant in Gisaid can be traced to 18 countries as of 20 February 2021.


Why RNA Is A Better Measure Of A Patient’s Current Health Than DNA

By harnessing the combined power of NGS, machine learning and the dynamic nature of RNA we’re able to accurately measure the dynamic immune response and capture a more comprehensive picture of what’s happening at the site of the solid tumor. In the beginning, there was RNA – the first genetic molecule.

In the primordial soup of chemicals that represented the beginning of life, ribonucleic acid (RNA) had the early job of storing information, likely with the support of peptides. Today, RNA’s cousin – deoxyribonucleic acid – or DNA, has taken over most of the responsibilities of passing down genetic information from cell-to-cell, generation-to-generation. As a result, most early health technologies were developed to analyze DNA. But, RNA is a powerful force. And its role in storing information, while different from its early years, has no less of an impact on human health and is gaining more mindshare in our industry.

RNA is often considered a messenger molecule, taking the information coded in our DNA and transcribing it into cellular directives that result in downstream biological signals and proteinslevel changes.  And for this reason, RNA is becoming known not only as a drug target but perhaps more importantly, as a barometer of health.

3d illustration of a part of RNA chain from which the deoxyribonucleic acid or DNA is composed

How and why is RNA so useful? First, RNA is labile — changing in both sequence and abundance in response to genetic and epigenetic changes, but also external factors such as disease, therapy, exercise, and more. This is in contrast to DNA, which is generally static, changing little after conception.

Next, RNA is a more accurate snapshot of disease progression. When mutations do occur at the DNA level, these do not always result in downstream biological changes. Often, the body is able to compensate by repairing the mutation or overcome it by using redundancies in the pathway in which the gene resides. By instead evaluating RNA, we get one step closer to understanding the real impact disease is imparting on our body.

Finally, RNA is abundant. In most human cells, while only two copies of DNA are present, hundreds of thousands of mRNA molecules are present,representing more than 10,000 different species of RNA. Because even rare transcripts are present in multiple copies, biological signals can be confidently detected in RNA when the right technology is used.


Colorectal Cancers Could Spread Before Detection

Colorectal cancer is the second leading cause of death from cancer in the United States. As with most cancers, it’s long been thought that early detection through routine screening is the key to stopping the spread of the disease to the liver or the brain (its preferred sites of metastasis).

Now, cancer geneticist Christina Curtis, PhD, together with postdoctoral scholar Zheng Hu, PhD, have learned that nearly 80 percent of metastatic colorectal cancers have likely already metastasized before the primary tumor is clinically detectable. They published their results in Nature Genetics. The finding turns a common belief about cancer development on its head.

Researchers and clinicians have assumed that cancers acquire the ability to metastasize through the gradual accumulation of molecular changes over time. These changes, the thinking goes, confer specific traits that eventually allow cancer cells to escape the surrounding tissue, enter the bloodstream and take up residence in new locations. In this scenario, metastasis, if it occurs, would be a relatively late event in the evolution of the primary cancer. Curtis and Hu were particularly interested in figuring out when and how the original, or primary, colorectal tumors acquired the ability to metastasize. To do so, they had to study both types of tumors from a series of individual patients, comparing the genomes of the cancer cells and then developing an new computational framework to piece the information together. Studying tumor biopsies, the researchers compared patterns of genetic mutations in the primary tumors of 23 patients with the patterns in their liver or brain metastases. They looked for similarities or differences between primary and metastatic cancers obtained from the same person. They then used those patterns to create a kind of evolutionary tree of each patient’s cancer — similar to one a biologist might make to trace the evolution of an animal species from a single ancestor. Their results weren’t exactly what they had suspected.

This finding was quite surprising. […] The cells that formed the metastasis were more closely related to the ancestors of the primary tumor than its present-day relatives. Moreover, the metastasis shared early drivers present in the ‘trunk’ of the evolutionary tree, but harbored few additional drivers. This suggested that these cancers acquired metastatic competence very early on during their growth“, Curtis explained.

The researchers went on to identify specific combinations of mutations that occur more frequently in metastatic disease. Curtis emphasizes that not all colorectal cancers metastasize (they specifically studied a subset of patients with metastatic cancer). She also cautioned against feeling like early detection is unimportant. On the contrary, it’s even more urgent.

These data indicate that metastasis can occur early in human colorectal cancer and highlights the critical need for the earlier detection of aggressive disease,” Curtis said. “New biomarkers based on specific combinations of alterations might enable the identification of potentially lethal colorectal tumors at an earlier stage so that they may be intercepted and appropriately treated, potentially with therapies directed against their specific aberrations.”


How To Treat Congenital Disease Before Birth

For the first time, scientists have performed prenatal gene editing to prevent a lethal metabolic disorder in laboratory animals, offering the potential to treat human congenital diseases before birth. Published today in Nature Medicine, research from the Perelman School of Medicine at the University of Pennsylvania and the Children’s Hospital of Philadelphia (CHOP) and offers proof-of-concept for prenatal use of a sophisticated, low-toxicity tool that efficiently edits DNA building blocks in disease-causing genes.

Using both CRISPR-Cas9 and base editor 3 (BE3) gene-editing tools, the team reduced cholesterol levels in healthy mice treated in utero by targeting a gene that regulates those levels. They also used prenatal gene editing to improve liver function and prevent neonatal death in a subgroup of mice that had been engineered with a mutation causing the lethal liver disease hereditary HT1 (HT1). HT1 in humans usually appears during infancy, and it is often treatable with a medicine called nitisinone and a strict diet. However, when treatments fail, patients are at risk of liver failure or liver cancer. Prenatal treatment could open a door to disease prevention, for HT1 and potentially for other congenital disorders.

Our ultimate goal is to translate the approach used in these proof-of-concept studies to treat severe diseases diagnosed early in pregnancy,” said study co-leader William H. Peranteau, MD, a pediatric and fetal surgeon in CHOP’s Center for Fetal Diagnosis and Treatment. “We hope to broaden this strategy to intervene prenatally in congenital diseases that currently have no effective treatment for most patients, and result in death or severe complications in infants.

We used base editing to turn off the effects of a disease-causing genetic mutation,” said study co-leader Kiran Musunuru, MD, PhD, MPH, an associate professor of Cardiovascular Medicine at Penn. “We also plan to use the same base-editing technique not just to disrupt a mutation’s effects, but to directly correct the mutation.” Musunuru is an expert in gene-editing technology and previously showed that it can be used to reduce cholesterol and fat levels in the blood, which could lead to the development of a “vaccination” to prevent cardiovascular disease.


CRISPR-SKIP, New Gene Editing Technique

What if doctors could treat previously incurable genetic diseases caused by errors or mutations in genes? Thanks to new research by American scientists at the University of Illinois, we are one step closer to making that a reality. Published in Genome Biology, their work is based on CRISPR-Cas9, a groundbreaking genome editing system.

Typically, cells in the body “readDNA to produce the proteins needed for different biological functions. . Scientists can change how the DNA is read using CRISPR gene-editing technology. CRISPR-Cas9 is often used to cut out specific areas of DNA and repair faulty genes. In the current study, the researchers modified existing technology to create CRISPR-SKIP. Instead of breaking DNA to cut faulty genes out, CRISPR-SKIP changes a single base of the targeted DNA sequence, causing the cell to skip reading that section of DNA.

According to the study authors, CRISPR-SKIP can eliminate faulty sections of DNA permanently, allowing for long-lasting treatment of some genetic diseases with one treatment. They successfully tested their technique in cell lines from both mice and humans. The scientists aim to test the method in live organisms in the future.

CRISPR-SKIP has the potential to help treat many diseases such as cancer, rheumatoid arthritis, Huntington’s disease, and Duchenne muscular dystrophy to name a few. Because the method only requires editing of a single base, it is simple, precise, and adaptable to a variety of cell types and applications.