Visit the News Hub
Discovery of receptor, generation of decoy could help contain outbreaks of Venezuelan equine encephalitis virus
Researchers at Washington University School of Medicine in St. Louis have identified a molecule that protects mice from brain infections caused by Venezuelan equine encephalitis virus (VEEV), a mosquito-borne virus notorious for causing fast-spreading, deadly outbreaks in Mexico, Central America and northern South America.
Researchers at Washington University School of Medicine in St. Louis have identified a molecule that protects mice from brain infections caused by Venezuelan equine encephalitis virus (VEEV), a mosquito-borne virus notorious for causing fast-spreading, deadly outbreaks in Mexico, Central America and northern South America. As the climate changes, the virus is likely to expand its range and threaten more countries in the Americas, including the U.S.
Public health officials have struggled to contain such outbreaks in the absence of effective drugs and vaccines. As a potential drug, the molecule described in a paper published Nov. 18 in the journal Nature could serve as a much needed tool to control the deadly virus.
This virus can infect many species of wild mammals, and every few years it jumps from animals to humans via mosquitoes and causes thousands of infections and many deaths, said senior author Michael S. Diamond, MD, PhD, the Herbert S. Gasser Professor of Medicine and a professor of molecular microbiology, and of pathology and immunology. Theres concern that with global warming and population growth, well get more outbreaks.
Once injected under the skin by mosquitoes, the virus homes in on neurons. People start experiencing symptoms such as headache, muscle pain, fatigue, vomiting, nausea, diarrhea, sore throat and fever within a week. In the most serious cases, the virus gets past the blood-brain barrier, causing encephalitis brain inflammation that can be fatal in up to a quarter of patients.
To find the potential drug, Diamond and colleagues including first authors Hongming Ma, PhD, an instructor in medicine, and Arthur S. Kim, PhD, a postdoctoral researcher began by searching for the protein handle on the surface of animal cells that the virus attaches to and uses to get inside cells. A drug that stops the virus from grabbing that handle, the scientists reasoned, could stymie infection and prevent disease.
But first they had to make a form of the virus they could work easily with. During the Cold War, the U.S. and the Soviet Union attempted to weaponize the virus, and it is still classified as a select agent, meaning only certain high-security labs are allowed to work with it. So instead, the researchers and their colleagues took Sindbis virus, a related virus that causes mild fever and rash, and swapped out some of its genes for some from VEEV. The resulting hybrid virus, called Sindbis-VEEV, infects cells like authentic VEEV but is unable to cause severe disease.
Using a genetic engineering technique known as genome-wide CRISPR screening, the researchers deleted genes in mouse neuronal cells until they found one called Ldlrad3 whose absence kept Sindbis-VEEV from infecting cells. The missing gene codes for a little-studied surface protein.
Further experiments verified the importance of Ldlrad3. Adding the gene back to neuronal cells restored the viruss ability to infect cells. The human LDLRAD3 gene is almost identical to its mouse equivalent, and knocking out the human gene also reduced infection in multiple cell lines. When the researchers added Ldlrad3 to a different cell type that is normally resistant to infection, the virus was able to infect the cell. Co-author William Klimstra, PhD, at the University of Pittsburgh, separately replicated the findings using authentic, highly virulent VEEV.
Ldlrad3 doesnt appear to be the only way the virus gets inside cells, since a small amount of virus is able to infect cells lacking the protein. But it is clearly the primary way in. Since Ldlrad3 is naturally on our cells and cant be removed, the scientists decided to create a decoy handle using a piece of the Ldlrad3 protein. Any virus particles that mistakenly latch onto the decoy handle would fail to infect cells and instead would get destroyed by the immune system.
To test their decoy in a living animal, the researchers injected mice with authentic virulent VEEV in two different ways: under the skin to mimic a mosquito bite, or directly into the brain. They gave the mice the decoy handle or a placebo molecule for comparison, either six hours before or 24 hours after infection. In all experiments, all of the mice that received the placebo died within a week. In most cases, all of the mice that received the decoy molecule survived, although in the most stringent experiment in which the virus was injected into the brain two of the 10 mice died despite receiving the decoy.
In an outbreak situation, you may be able to use a drug like this as a countermeasure to prevent transmission and further spread, Diamond said.
A major advantage to an antiviral drug based on a human rather than a viral protein is that it is unlikely the virus could evolve resistance to it. Any mutation that enables the virus to avoid the decoy probably would make it unable to attach to cells, too, the researchers said.
Ma H, Kim AS, Kafai NM, Earnest JT, Shah A, Case JB, Basore K, Gilliland TC, Sun C, Nelson CA, Thackray LB, Klimstra WB, Fremont DH, Diamond MS. LDLRAD3 is a receptor for Venezuelan equine encephalitis virus. Nature. Nov. 18, 2020. DOI: 10.1038/s41586-020-2915-3
This study was supported by the National Institutes of Health (NIH), grant numbers R01AI143673, U19AI142790, R01AI095436 and T32 AI007172 and contract number HHSN272201700060C; and the Defense Reduction Threat Agency, grant numbers HDTRA1-15-1-0013 and HDTRA1-15-1-0047.
Washington University School of Medicines 1,500 faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Childrens hospitals. The School of Medicine is a leader in medical research, teaching and patient care, ranking among the top 10 medical schools in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Childrens hospitals, the School of Medicine is linked to BJC HealthCare.
View post:
- IOM not webcast today. Why Not? - November 8th, 2009 [November 8th, 2009]
- National Academies skeptical at Best. - November 8th, 2009 [November 8th, 2009]
- Some Confusion Exists - November 8th, 2009 [November 8th, 2009]
- Why DTC Genomics IS Medicine. - November 8th, 2009 [November 8th, 2009]
- First Mari, Now Linda. Who's next? - November 8th, 2009 [November 8th, 2009]
- Is it true? - November 8th, 2009 [November 8th, 2009]
- Re-Reviewing the National Academies - November 8th, 2009 [November 8th, 2009]
- The problem with nonclinicians....... - November 8th, 2009 [November 8th, 2009]
- Crazy Night of Emails to Government - November 8th, 2009 [November 8th, 2009]
- Adrienne Carlson's Personalized Medicine. - November 8th, 2009 [November 8th, 2009]
- Tell Me, How do you feel now? Sherpa's RX - November 8th, 2009 [November 8th, 2009]
- This Just In. 23andMe to go to GPs. I love my readers!! - November 8th, 2009 [November 8th, 2009]
- Sorry so long away - November 8th, 2009 [November 8th, 2009]
- 2D6 Rears its ugly head..... - November 8th, 2009 [November 8th, 2009]
- Ok, Fine, Back to Plavix - November 8th, 2009 [November 8th, 2009]
- Kaiser a protoype for Collins' Aim - November 8th, 2009 [November 8th, 2009]
- A few months late to the party.... - November 8th, 2009 [November 8th, 2009]
- Stated Another Way....... - November 8th, 2009 [November 8th, 2009]
- Excuse Me? Harvard and Navigenics? WTF? - November 8th, 2009 [November 8th, 2009]
- Follow up to Yesterday's WTF? Harvard, Navi? and Pfizer??? - November 8th, 2009 [November 8th, 2009]
- Did you get your kit? Thanks Dr. Rob from MedCo - November 8th, 2009 [November 8th, 2009]
- Gluco...Wha? Parkinson's Disease and Glucocerebrosidase mutations. - November 8th, 2009 [November 8th, 2009]
- Away and now back, What did I miss???? 23andme layoffs? Selling Genomes for cheap up next! - November 8th, 2009 [November 8th, 2009]
- Change IS Needed. I agree with William, sometimes. - November 8th, 2009 [November 8th, 2009]
- Good Enough Science? Apparently so at 23andme - November 8th, 2009 [November 8th, 2009]
- Long QT Syndrome, location matters - December 13th, 2009 [December 13th, 2009]
- Congratulations Generation Health. Nice pick up! - December 13th, 2009 [December 13th, 2009]
- An argument 23andSerge can't win...23andme but not medicine - December 13th, 2009 [December 13th, 2009]
- Stop. Breathe. Repeat. An analysis of the direction of DTC Genomics Field. - December 13th, 2009 [December 13th, 2009]
- Hey DTC genomics, Stay Private, Stay Alive, Go Public and Die - December 13th, 2009 [December 13th, 2009]
- You can't have it both way. Either scared your genome is sold off or not. - December 13th, 2009 [December 13th, 2009]
- 15 Days Away Gives Time for Perspective. - December 13th, 2009 [December 13th, 2009]
- What about the SACGHS registry? Another missed opportunity? - December 13th, 2009 [December 13th, 2009]
- AJHG is in and my Favorite Muin is in it! But He Is NOT the Father! - December 13th, 2009 [December 13th, 2009]
- Navigenics for 23andMe prices? - December 18th, 2009 [December 18th, 2009]
- Lp(a) Maybe there's something there that wasn't there before? - December 24th, 2009 [December 24th, 2009]
- Another Year, Another Bankruptcy - December 31st, 2009 [December 31st, 2009]
- 5 Technologies going bye bye in this decade? - January 6th, 2010 [January 6th, 2010]
- Hackers, HITECH and HIPAA in DTC Genomics, Oh My! - January 7th, 2010 [January 7th, 2010]
- Personal Genomics Flop.....big Belly Flop! - January 8th, 2010 [January 8th, 2010]
- Gotta Love It. Even the daycare....... - January 11th, 2010 [January 11th, 2010]
- Congratulations Navigenics. You ARE a clinical lab! Uh-Oh... - January 12th, 2010 [January 12th, 2010]
- CETP, Jewish Centenarians and Alzheimers - January 14th, 2010 [January 14th, 2010]
- Enter the "Not" DTC Genomics Rep - January 17th, 2010 [January 17th, 2010]
- Why Dr. Vanier's Navigenics appointment is good for PM - January 22nd, 2010 [January 22nd, 2010]
- Holy Crap! MedCo Follows in CVS footsteps - February 3rd, 2010 [February 3rd, 2010]
- FDA, Warfarin, still not as sexy to me. - February 5th, 2010 [February 5th, 2010]
- Hype, Hype, Hype from a single study. - February 11th, 2010 [February 11th, 2010]
- I love my readers, even Renata M! - February 17th, 2010 [February 17th, 2010]
- How can insurers use DTC genomics to profile? - February 17th, 2010 [February 17th, 2010]
- 9p21.....ahem. Paynter et.al. Smackdown. Again. - February 18th, 2010 [February 18th, 2010]
- Hey! It's Pete Hulick! Are you Going to GET? - February 19th, 2010 [February 19th, 2010]
- I was wrong......AHEM - February 28th, 2010 [February 28th, 2010]
- G2C2, finally a tool for genomic education! - March 2nd, 2010 [March 2nd, 2010]
- Just 4 million? What 23andMe is worth. - March 5th, 2010 [March 5th, 2010]
- What a difference a year makes - March 9th, 2010 [March 9th, 2010]
- ........DTC Genomic Medicine? - March 12th, 2010 [March 12th, 2010]
- The FDA, 2c19 and the ACC - March 13th, 2010 [March 13th, 2010]
- The problem with Comparative Whole Genomics...... - March 13th, 2010 [March 13th, 2010]
- BRCA testing by 23andME is the same as Myriad Genetics. - March 15th, 2010 [March 15th, 2010]
- The Argument Against DTC Genomics Marketing and such - March 16th, 2010 [March 16th, 2010]
- A moment of Clarity. Some DTCG is not bad. - March 18th, 2010 [March 18th, 2010]
- SNPs for breast cancer risk? It Depends. - March 18th, 2010 [March 18th, 2010]
- How can MDVIP use Navigenics Test for Medicine? - March 18th, 2010 [March 18th, 2010]
- Why did P&G invest in Navigenics? - March 23rd, 2010 [March 23rd, 2010]
- PGx in DTCG? Doesn't stand up to Useful testing. - March 25th, 2010 [March 25th, 2010]
- End of Gene Patents? - March 29th, 2010 [March 29th, 2010]
- Sherpa Accepting Chief Medical Officership - April 3rd, 2010 [April 3rd, 2010]
- The Rumors of My Death........ - April 20th, 2010 [April 20th, 2010]
- Happy DNA Day! - April 25th, 2010 [April 25th, 2010]
- 99 USD, DNA day and patient letters - April 25th, 2010 [April 25th, 2010]
- 2C19, Navigenics and Clinical Reality. - May 1st, 2010 [May 1st, 2010]
- Coriell Personalized Medicine Collaborative rising - May 7th, 2010 [May 7th, 2010]
- Personal Genomes in Clinical Care. Quake paper is a waste! - May 11th, 2010 [May 11th, 2010]
- Personal Genomes in Clinical Care. Quake paper Falls Short! - May 13th, 2010 [May 13th, 2010]
- Last post edited by Drew - May 13th, 2010 [May 13th, 2010]
- GateKeeper? FCUK U! - May 13th, 2010 [May 13th, 2010]
- GateKeeper? F! U! - May 15th, 2010 [May 15th, 2010]
- Potential of genomic medicine, LOST - May 19th, 2010 [May 19th, 2010]
- How Bad Can a House Investigation be for DTC Genomics? - May 20th, 2010 [May 20th, 2010]