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Laboratory & Clinical

Doctors Try 1st CRISPR Editing in the Body for Blindness

Genetic Frontiers Gene Editing Blindness
Dr. Jason Comander, inherited retinal disorder specialist at Massachusetts Eye and Ear Infirmary in Boston points to a model of an eye during an interview on Jan. 8, 2020. Comander's hospital plans to enroll patients in a gene editing treatment for blindness study. He said it marks “a new era in medicine” using a technology that “makes editing DNA much easier and much more effective.” (AP Photo/Rodrique Ngowi)

Scientists say they have used the gene editing tool CRISPR inside someone’s body for the first time, a new frontier for efforts to operate on DNA, the chemical code of life, to treat diseases.

A patient recently had it done at the Casey Eye Institute at Oregon Health & Science University in Portland for an inherited form of blindness, the companies that make the treatment announced Wednesday. They would not give details on the patient or when the surgery occurred.

It may take up to a month to see if it worked to restore vision. If the first few attempts seem safe, doctors plan to test it on 18 children and adults.

“We literally have the potential to take people who are essentially blind and make them see,” said Charles Albright, chief scientific officer at Editas Medicine, the Cambridge, Massachusetts-based company developing the treatment with Dublin-based Allergan. “We think it could open up a whole new set of medicines to go in and change your DNA.”

Dr. Jason Comander, an eye surgeon at Massachusetts Eye and Ear in Boston, another hospital that plans to enroll patients in the study, said it marks “a new era in medicine” using a technology that “makes editing DNA much easier and much more effective.”

Doctors first tried in-the-body gene editing in 2017 for a different inherited disease using a tool called zinc fingers. Many scientists believe CRISPR is a much easier tool for locating and cutting DNA at a specific spot, so interest in the new research is very high.

The people in this study have Leber congenital amaurosis, caused by a gene mutation that keeps the body from making a protein needed to convert light into signals to the brain, which enables sight. They’re often born with little vision and can lose even that within a few years.

Scientists can’t treat it with standard gene therapy — supplying a replacement gene — because the one needed is too big to fit inside the disabled viruses that are used to ferry it into cells.

So they’re aiming to edit, or delete the mutation by making two cuts on either side of it. The hope is that the ends of DNA will reconnect and allow the gene to work as it should.

It’s done in an hour-long surgery under general anesthesia. Through a tube the width of a hair, doctors drip three drops of fluid containing the gene editing machinery just beneath the retina, the lining at the back of the eye that contains the light-sensing cells.

“Once the cell is edited, it’s permanent and that cell will persist hopefully for the life of the patient,” because these cells don’t divide, said one study leader not involved in this first case, Dr. Eric Pierce at Massachusetts Eye and Ear.

Doctors think they need to fix one tenth to one third of the cells to restore vision. In animal tests, scientists were able to correct half of the cells with the treatment, Albright said.

The eye surgery itself poses little risk, doctors say. Infections and bleeding are relatively rare complications.

One of the biggest potential risks from gene editing is that CRISPR could make unintended changes in other genes, but the companies have done a lot to minimize that and to ensure that the treatment cuts only where it’s intended to, Pierce said. He has consulted for Editas and helped test a gene therapy, Luxturna, that’s sold for a different type of inherited blindness.

Some independent experts were optimistic about the new study.

“The gene editing approach is really exciting. We need technology that will be able to deal with problems like these large genes,” said Dr. Jean Bennett, a University of Pennsylvania researcher who helped test Luxturna at the Children’s Hospital of Philadelphia.

In one day, she had three calls from families seeking solutions to inherited blindness.

“It’s a terrible disease,” she said. “Right now they have nothing.”

Dr. Kiran Musunuru, another gene editing expert at the University of Pennsylvania, said the treatment seems likely to work, based on tests in human tissue, mice and monkeys.

The gene editing tool stays in the eye and does not travel to other parts of the body, so “if something goes wrong, the chance of harm is very small,” he said. “It makes for a good first step for doing gene editing in the body.”

Although the new study is the first to use CRISPR to edit a gene inside the body, another company, Sangamo Therapeutics, has been testing zinc finger gene editing to treat metabolic diseases.

Other scientists are using CRISPR to edit cells outside the body to try to treat cancer, sickle cell and some other diseases.

All of these studies have been done in the open, with government regulators’ approval, unlike a Chinese scientist’s work that brought international scorn in 2018. He Jiankui used CRISPR to edit embryos at the time of conception to try to make them resistant to infection with the AIDS virus. Changes to embryos’ DNA can pass to future generations, unlike the work being done now in adults to treat diseases.

via – VOA | Source – VOA | Search  》CRISPR Gene Editing

An emerging Irish technology may be key to containing the Wuhan coronavirus

The COVID-19 pandemic is challenging laboratories worldwide to find solutions.

coronavirus-research-emerging-irish-technology
Aquila Bioscience at NUIG, Galway, Ireland may have developed containment technology. (iStock/Getty Images)

Aquila Bioscience at NUIG has developed a technology, called Abwipe, which they say could prove a useful countermeasure to the Wuhan coronavirus, Covid-19. The technology was originally designed in consultation with the European Defence Agency to protect military and emergency personnel from biological agents such as anthrax.

Professor Lokesh Joshi, vice-president of research at NUIG and founder of Aquila Bioscience, told Gript that the technology currently takes the form of wipes, but that it could easily be adapted to masks and other protective clothing should circumstances require them.

The technology works by trapping microbes within a material, where they can be safely disposed of. As Covid-19 appears to be spread primarily through droplets or through contact with a surface that an infected person has coughed or sneezed on, the wipes would allow a person to easily remove Covid-19 from their hands or the surfaces around them. Removing the risk of infection.

The technology involved may also prove invaluable when dealing with antibiotic resistant bacteria as the technology does not involve any antibiotic treatment. According to the World Health Organisation at least 700,000 people die each year to drug-resistant diseases.

Professor Lokesh Joshi, vice-president of research at NUIG and founder of Aquila Bioscience, told Gript that Aquilla’s technology has passed through testing and that discussions with manufacturers are currently ongoing.

via – Gript | Source – Gript | Search Corona Virus Research

Advancements in Liver Cancer Testing Using DNA Markers

Latest testing techniques using DNA Markers look promising.

Liver-Cancer-Testing
Liver Cancer Testing (iStock/Getty Images)

Early diagnosis and treatment of cancer tumor in soft tissues vastly increases the odds for survival. Liver cancer can be difficult to detect, often not manifesting symptoms until it’s in a more advanced stage. Imagine if your own body could be the key to unlocking a better way of finding early signs of liver cancer?

Catching Early-Stage Tumors

That could soon be possible thanks to ongoing research at Mayo Clinic developing a using DNA markers to look for liver cancer in its earliest stages. Current tests have difficulty locating the presence of liver cancer when it’s in a more curable stage.

How the Test Works

The test compares atypical DNA markers found in liver cancer patients to alpha-fetoprotein, a protein produced in the liver during the fetal development stage. The latest round of testing located curable tumors in more than 90% of patients participating in the trial. These same markers were undetectable in either healthy individuals or cirrhosis patients not currently suffering from tumors.

The Next Steps

The next phase for the research group involves using the test on a larger pool of test subjects. If the results hold up, this represents a real breakthrough that could save many lives. The success of this test could also encourage other researchers to use DNA markers in similar ways to help with other cancers that can be difficult to diagnose in its earlier stages.

Are you interested in keeping up with the latest in medicine? Find out more about various research being conducted at Mayo Clinic by signing up for Forefront Magazine, an designed to keep you informed about the latest in medical advances.

via – Medium.com | Source – T.J.Manning

Scientists Produce 3D Map of SARS-CoV-2’s Spike Protein

Researchers have made a breakthrough toward developing a vaccine for the SARS-CoV-2 coronavirus, also known as 2019-nCoV, by creating the first 3D atomic scale map of its spike protein, part of a virus that attaches to and infects human cells.

SARS-CoV-2-transmission-electron-microscope
This transmission electron microscope image shows SARS-CoV-2, also known as 2019-nCoV, the virus that causes COVID-19, isolated from a patient in the U.S., emerging from the surface of cells cultured in the lab. Image credit: NIAID-RML.

“The novel coronavirus has recently emerged as a human pathogen in the city of Wuhan in China’s Hubei province, causing fever, severe respiratory illness and pneumonia, a disease recently named COVID-19,” said senior author Dr. Jason McLellan from the Department of Molecular Biosciences at the University of Texas at Austin and colleagues.

“The emerging pathogen was rapidly characterized as a novel member of the betacoronavirus genus, closely related to several bat coronaviruses as well as SARS-CoV.”

“Compared to SARS-CoV, SARS-CoV-2 appears to be more readily transmitted from human-to-human, spreading to multiple continents.”

“It makes use of a densely glycosylated spike protein to gain entry into host cells.”

Dr. McLellan team had already developed methods for locking spike proteins in other coronaviruses, including SARS-CoV and MERS-CoV, into a shape that made them easier to analyze and could effectively turn them into candidates for vaccines.

This experience gave them an advantage over other research teams studying the novel virus.

“As soon as we knew this was a coronavirus, we felt we had to jump at it, because we could be one of the first ones to get this structure,” Dr. McLellan said.

“We knew exactly what mutations to put into this, because we’ve already shown these mutations work for a bunch of other coronaviruses.”

Structure-SARS-CoV-2’s spike-0protein
Structure of SARS-CoV-2’s spike protein: (A) schematic of the spike protein’s primary structure, colored by domain; domains that were excluded from the ectodomain expression construct or could not be visualized in the final map are colored white. Abbreviations: SS – signal sequence, NTD – N-terminal domain, RBD – receptor-binding domain, SD1 – subdomain 1, SD2 – subdomain 2, S1/S2 – S1/S2 protease cleavage site, S2′ – S2′ protease cleavage site, FP – fusion peptide, HR1 – heptad repeat 1, CH – central helix, CD – connector domain, HR2 – heptad repeat 2, TM – transmembrane domain, CT – cytoplasmic tail; arrows denote protease cleavage sites; (B) side and top views of the prefusion structure of SARS-CoV-2’s spike protein with a single RBD in the up conformation; the two RBD-down protomers are shown as cryo-EM density in either white or gray and the RBD-up protomer is shown in ribbons, colored corresponding to the schematic in (A). Image credit: Wrapp et al, doi: 10.1126/science.abb2507.

Just two weeks after receiving the genome sequence of the SARS-CoV-2 virus, the researchers had designed and produced samples of its stabilized spike protein.

It took about 12 more days to reconstruct the 3D atomic scale map, called a molecular structure, of the spike protein.

Critical to the success was state-of-the-art technology known as cryogenic electron microscopy (cryo-EM), which allows scientists to make atomic-scale 3D models of cellular structures, molecules and viruses.

The molecule the team produced, and for which they obtained a structure, represents only the extracellular portion of the spike protein, but it is enough to elicit an immune response in people, and thus serve as a vaccine.

Next, the authors plan to use their molecule to pursue another line of attack against the SARS-CoV-2 virus, using the molecule as a ‘probe’ to isolate naturally produced antibodies from patients who have been infected with the novel coronavirus and successfully recovered.

In large enough quantities, these antibodies could help treat a coronavirus infection soon after exposure. For example, the antibodies could protect soldiers or health care workers sent into an area with high infection rates on too short notice for the immunity from a vaccine to take effect.

The team’s results are published in the journal Science.

Remdesivir antiviral – potential treatment for COVID-19

The discovery that the antiviral drug remdesivir prevented MERS-CoV disease in monkeys supports the clinical trial testing of remdesivir as a treatment for COVID-19.

Remdesivir-antiviral
remdesivir is a promising antiviral treatment against MERS that could be considered for implementation in clinical trials. This colorized scanning electron micrograph shows MERS virus particles (blue) both budding and attached to the surface of infected VERO E6 cells (yellow). Image credit: NIAID.

Three different coronavirus outbreaks (SARS, MERS, COVID-19) have emerged from animal reservoirs in the past two decades that have caused severe disease and concerns over global spread.

The Middle East Respiratory Syndrome coronavirus (MERS-CoV) first appeared in 2012, eight years after the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) first emerged from China in late 2002/2003.  Although no cases of SARS-CoV have been detected since 2004, MERS-CoV continues to circulate with 2,499 reported cases and 861 deaths as of December 2019. The case fatality rate of MERS-CoV is 35% as compared to SARS-CoV which was around 10%.

Since the emergence of MERS-CoV, scientists have focused on developing animal models in which to test new treatments. Currently, there are no FDA-approved antivirals or vaccines for the treatment and prevention of MERS-CoV.

However, a new report from NIH’s National Institute of Allergy and Infectious Diseases (NIAID), published in the Proceedings of the National Academy of Sciences describes a step forward for remdesivir in the approval process for coronavirus treatment.

Remdesivir is an experimental antiviral drug with broad activity

Remdesivir (GS-5734) created in 2014 by the biotechnology company Gilead in Foster City, California was initially developed to fight infectious viral diseases such as Ebola.  As a nucleotide analogue prodrug, it is not active outside the cell. Studies indicate that in the cell, it is metabolized into more active metabolites that inhibit coronavirus replication through interference with viral enzymes (RNA polymerases) that are necessary for replication. Host RNA or DNA polymerases are not affected.

Studies have demonstrated that MERS-CoV enters cells with the help of an S protein or spike to help attach to host cells. The virus then hijacks or delays the normal immune system response as the infection steadily progresses.

Already, remdesivir has proven effective in treating monkeys infected with Ebola and Nipah viruses and human clinical trials are currently underway. Thus far, studies suggest that two other drugs are more effective than remdesivir in treating Ebola.

Multiple in vitro (test tube) studies have demonstrated that remdesivir has broad antiviral activity against viruses from different families (including filo-, pneumo-, and paramyxoviruses) without any noted adverse toxic effects.  For example, replication of a wide range of coronaviruses including SARS-CoV and MERS-CoV was inhibited in human airway (lung) epithelial cells.

In vivo studies with mice also demonstrated that remdesivir was effective against SARS-CoV.

Remdesivir prevented MERS-CoV in monkeys when administered before infection and improved disease symptoms when administered after the animals were infected.

Researchers randomly assigned 18 male rhesus macaques to three groups of six at NIAID’s Rocky Mountain Laboratories in Hamilton, Montana.

One group of monkeys was treated prophylactically (24 h before MERS-CoV infection) with 5 mg/kg remdesivir. Another group was similarly given 5 mg/kg remdesivir but therapeutically (12 h after MERS-CoV infection which is close to the peak time for MERS-CoV replication).  A control group did not receive any remdesivir. The treatment was continued once daily for six days. On the sixth day, researchers assessed viral RNA levels and lesions (damage) present in lung tissues.

The researchers observed signs of respiratory disease in the control group, which included increased respiration rates and lung lesions that consisted of minimal to marked interstitial pneumonia.

Animals treated prophylactically exhibited normal lung tissue with significantly lower levels of MERS-CoV replication compared to the control group. No lesions were present in the lung tissues.

Since one-third of MERS-CoV cases are acquired in the hospital (through nosocomial transmission), prophylactic remdesivir treatment could prevent disease in healthcare personnel or individuals who are in close contact with already diagnosed MERS-CoV patients.

For patients already diagnosed with MERS-CoV, remdesivir may reduce virus replication and decrease the severity of lung lesions.

Five out of six animals treated with remdesivir after infection had increased respiration rates that were still significantly lower than the control group at days three and six. This group also demonstrated lower levels of MERS-CoV replication in the lungs than the control group but levels were higher than the prophylactically treated group.

Moreover, the total area of lungs affected by lesions was significantly smaller than the control group and the lung damage was less severe.

Researchers observed various levels of pneumonia severity when treated therapeutically. Two out of six animals did not show any evidence of pneumonia.

Clinical trials of remdesivir for COVID-19 are currently underway and needed for MERS-CoV

Now that remdesivir has demonstrated in vitro and in vivo activity in animal models against SARS-CoV and MERS-CoV, which are coronaviruses that are structurally similar to COVID-19, there is potential for it to be also effective as a treatment for COVID-19.

The drug is being advanced into human clinical trials for COVID-19 treatment in China, given the current necessity for treatment.  Results from these studies are expected to be available this spring.

Even though remdesivir is not yet licensed or approved by any drug regulators globally and there is no data available on its effectiveness as a treatment for COVID-19, it has been administered for emergency treatment in a small number of patients with in the absence of other approved treatment options. No adverse effects have been seen in these cases.

References:

  • Wit, E. de, Feldmann, F., Cronin, J., Jordan, R., Okumura, A., Thomas, T., … Feldmann, H. (2020, February 13). Prophylactic and therapeutic remdesivir (GS-5734) treatment in the rhesus macaque model of MERS-CoV infection. Retrieved from https://www.pnas.org/content/early/2020/02/12/1922083117#F3
  • (n.d.). Remdesivir prevents MERS coronavirus disease in monkeys. Retrieved from https://www.eurekalert.org/pub_releases/2020-02/nioa-rpm021320.php
  • Characterizing MERS-CoV Disease. (n.d.). Retrieved from https://www.niaid.nih.gov/diseases-conditions/characterizing-mers-cov-disease
  • (n.d.). Retrieved from https://www.gilead.com/science-and-medicine/pipeline
  • Severe 2019-nCoV Remdesivir RCT – Tabular View. (n.d.). Retrieved from https://clinicaltrials.gov/ct2/show/record/NCT04257656
  • Company Statements. (n.d.). Retrieved from https://www.gilead.com/news-and-press/company-statements/gilead-sciences-statement-on-the-company-ongoing-response-to-the-2019-new-coronavirus
  • Gilead Assesses Ebola Drug as Possible Coronavirus Treatment (1). (n.d.). Retrieved from https://news.bloomberglaw.com/pharma-and-life-sciences/gilead-assesses-ebola-drug-as-possible-coronavirus-treatment
  • https://www.who.int/ebola/drc-2018/summaries-of-evidence-experimental-therapeutics.pdf?ua=1
  • https://www.nature.com/articles/srep43395