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Research Adds to Arsenal of Treatments for Rheumatoid Arthritis

Source: Brigham and Women's Hospital - On a Mission
Date: 12/04/2019
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Beginning with methotrexate in the mid-1980s, clinical investigators at Brigham and Women’s Hospital have led the development of a number of drugs for treating rheumatoid arthritis (RA). Thanks to methotrexate and additional progress in the decades since it was approved, the majority of people with RA now experience effective disease management.

“I can confidently say that treatments for RA today are very effective and will continue to improve going forward,” said Elena M. Massarotti, MD, of the Brigham’s Division of Rheumatology, Inflammation and Immunity. “But there are still challenges to overcome.”

One of the biggest of these challenges is that despite effective therapies, 30 percent of patients are unable to achieve complete disease control. This reality drives the continued focus on research into the causes and drivers of RA and the search for additional drugs.

“About one-third of patients with RA go into remission with methotrexate alone,” said Michael E. Weinblatt, MD, co-director of clinical rheumatology and associate director of the Center for Arthritis and Joint Diseases at the Brigham. “Many more can achieve remission with the addition of other drugs. But we still have about 10 percent of patients with high disease activity, and another 20 percent with disease activity in the moderate range. Their disease has improved, but they’re not where we want them to be.”

Encouraging Signs

Other types of drugs that have greatly improved the treatment of RA by targeting the chronic inflammation that leads to the disease include inhibitors of tumor necrosis factor, inhibitors of IL-6, T cell costimulatory blocking agents, B cell depleting agents and new oral agents that block inflammation.

Controlling RA in a timely fashion is vital because structural damage caused by the inflammation progresses over time. “Fortunately, the need for surgery in people with RA is much less common than it was 15 or 20 years ago,” Dr. Massarotti said. “I’m sending fewer and fewer people for joint replacements. This is because the medical treatments have gotten so much better.”

The Brigham sees about 4,500 people with RA every year. This high volume gives its rheumatologists insights into what works as well as where further research is needed. A patient registry called the Brigham and Women’s Hospital RA Sequential Study (BRASS) also contributes to advances in clinical research for RA.

“We’ve enrolled about 1,500 patients in this registry,” Dr. Weinblatt said. “Some of them have been followed for more than 18 years. It’s greatly increased our understanding of the pathogenesis of the disease and of which factors are active in RA. It also allows us to study the side effects of these drugs.”

The registry serves as a clinical database and a sample repository. According to Dr. Weinblatt, more than 80 papers have come out of the BRASS dataset. In addition, the clinical data and samples are made available to investigators from all over the world who are studying RA.

The Search for Genetic Markers

One important goal of the Brigham’s RA team, along with RA investigators more broadly, is developing biomarkers to predict which people will respond to which therapies. “When a patient walks into the exam room, we have no idea which drug or drugs will be best for them,” Dr. Weinblatt said. “We would like to develop programs that can identify for each individual which treatments will work. This includes the search for genetic markers.”

“The Brigham has a long history of treating people with RA, even before methotrexate,” Dr. Massarotti said, referencing the institution’s status as the country’s first teaching hospital devoted to arthritis and other rheumatic diseases. “And we will continue to lead the way into the future.”

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Tobacco plants engineered to manufacture high yields of malaria drug

Source: Cell Press
Date: 10/20/16
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In 2015, the Nobel Prize in Physiology or Medicine was awarded in part for the discovery of artemisinin, a plant-derived compound that’s proven to be a lifesaver in treating malaria. Yet many people who need the drug are not able to access it, in part because it’s difficult to grow the plant that is the compound’s source. Now, research has shown that tobacco plants can be engineered to manufacture the drug at therapeutic levels. The study appears October 20 in Molecular Plant.

“Artemisinin treats malaria faster than any other drug. It can clear the pathogen from the bloodstream within 48 hours,” says senior author Shashi Kumar, of the International Centre for Genetic Engineering and Biotechnology in New Delhi, India. “Our research is focused on finding a way to make this drug available to more people.”

Malaria infects more than 200 million people every year, according to the World Health Organization, and kills more than 400,000, mostly in Africa and Southeast Asia. The majority of those who live in malaria-stricken areas cannot afford to buy artemisinin. The drug’s high cost is due to the extraction process and largely to the fact that it’s difficult to grow Artemisia annua (sweet wormword), the plant that is the original source of the drug, in climates where malaria is common, such as in India. Advances in synthetic biology have made it possible to produce the drug in yeast, but the manufacturing process is difficult to scale up.

Earlier studies looked at growing the compound in tobacco–a plant that’s relatively easy to genetically manipulate and that grows well in areas where malaria is endemic. But yields of artemisinin from those plants were low.

In the current paper, Kumar’s team reports using a dual-transformation approach to boost the production of artemisinin in the tobacco plants: they first generated plants that contained transgenic chloroplasts, and the same plants were then manipulated again to insert genes into the nuclear genome as well. “We rationalized the expression of biosynthetic pathway’s gene in different compartment that enabled us to reach the maximum yield from the double transgenic plants,” he says.

Extract from the plants was shown to stop the growth progression of pathogen-infected red blood cells in vitro. Whole cells from the plant were also fed to mice infected with Plasmodium berghei, one of the microbes that causes malaria. The plant product greatly reduced the level of the parasite in the blood. In fact, the researchers found, the whole plant material was more effective in attacking the parasite than pure artemisinin, likely because encapsulation inside the plant cells protected the compound from degradation by digestive enzymes.

But Kumar and his colleagues acknowledge that convincing people to eat tobacco plants is likely to be a hard sell. For that reason, he is collaborating with Henry Daniell, a professor of biochemistry at the University of Pennsylvania and one of the study’s coauthors, with a plan to genetically engineer lettuce plants for producing artemisinin. The lettuce containing the drug can then be freeze dried, ground into a powder, and put into capsules for cost-effective delivery.

“Plant and animal science are increasingly coming together,” Kumar says. “In the near future, you will see more drugs produced inside plants will be commercialized to reduce the drug cost.”

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Mapping the routes to drug resistance in cancer

Source: Cell Press
Date: 04/11/16
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When a freeway shuts down because of an accident or construction, drivers find another road to take them where they’re going. Likewise, when a targeted therapy blocks a pathway that enables tumors to grow, the cells usually manage to get around that obstacle. The result is drug resistance. Researchers have now found a way to map those alternate routes by studying individual cancer cells, suggesting approaches for developing more effective combination therapies. The results are published April 11 in Cancer Cell.

“Because technology now allows us to see the alternate pathways that cancer cells use to drive growth, it will enable us to identify ways to cut off multiple roads at the same time,” says James Heath, one of the paper’s corresponding authors, at the NanoSystems Biology Cancer Center in the Division of Chemistry and Chemical Engineering at the California Institute of Technology.

In the study, the investigators primarily looked at glioblastoma, the most deadly form of brain cancer. Although therapies tailored based on genetic alterations in these tumors have been developed, their benefit is usually short-lived. Combination therapies, which target multiple alterations at the same time, may offer a better way to fight this disease.

“Figuring out why resistance to targeted therapies develops has been the focus of our research for a long time,” says Paul Mischel, the paper’s co-corresponding author, at the Ludwig Institute for Cancer Research at the University of California, San Diego. “In this study, we looked at a drug that should work and found out why it doesn’t.”

The technology the team used is called single-cell phosphoproteomics. This tool enables investigators to peer into the inner workings of individual cancer cells and see their signaling. Using patient tissues obtained directly from operating rooms, the researchers found that the cells began to adapt to and resist therapies that target the growth pathway called mTOR in as little as 48 hours. Analysis showed that these cells were remapping their routes and finding ways to evade the drug’s effect long before any changes could be detected at the clinical level.

The investigators say that this approach could eventually be used to find better combination therapies for glioblastoma, but obstacles remain. “Although the technology used to analyze the cells is relatively simple and inexpensive–just glass and plastic–trials will be difficult to design,” says Heath. “For this type of personalized treatment, we won’t know what drugs to give patients until after their tumors are analyzed. Every trial will essentially have a sample size of one.”

Mischel adds that there are additional challenges in developing drugs for glioblastoma because they must be able to cross the blood-brain barrier.

In the paper, the researchers also described that single-cell phosphoproteomics could be used to study how melanoma cells develop resistance to a class of drugs called BRAF inhibitors. The single-cell-analysis approach could likely be employed to develop personalized treatment for many other types of cancer as well.

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Antibody Combination Puts HIV on the Ropes

Source: Rockefeller University, Newswire
Date: 01/25/17
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Without antiretroviral drug treatment, the majority of people infected with HIV ultimately develop AIDS, as the virus changes and evolves beyond the body’s ability to control it. But a small group of infected individuals—called elite controllers—possess immune systems capable of defeating the virus. They accomplish this by manufacturing broadly neutralizing antibodies, which can take down multiple forms of HIV.

Now a study using antibodies from one of these elite controllers has shown that a combination of three such antibodies can completely suppress the virus in HIV-infected mice. The findings, from the laboratory of Michel C. Nussenzweig, who is Zanvil A. Cohn and Ralph M. Steinman Professor at The Rockefeller University and head of the Laboratory of Molecular Immunology, are being reported in Science Translational Medicine.

“Some people with HIV produce these antibodies, but most of the time the virus eventually escapes them through mutations in the antibody’s corresponding epitope,” says postdoctoral fellow Natalia Freund, the study’s first author. The epitope is the part of the virus that antibodies recognize and attach themselves to, and this ability to mutate makes HIV particularly tricky to tame. It ensures that once the virus is in their bodies, people remain infected forever, and this may be the biggest roadblock in developing immune therapies to overcome the virus.

Tug of war

“Think of the relationship between the antibodies and the virus as an arms race that goes on and on,” Freund says. “By mutating, some of the virus may escape the antibodies and continue growing. Years later, the body may produce new broadly neutralizing antibodies against the escaped virus, which in turn may mutate and escape yet again.”

“What we’ve shown in this study is that after several rounds of escape from these particular antibodies, the virus seems to run out of options,” she adds. “In this particular case, HIV eventually loses this arms race.”

An elite controller’s immune system can defeat the virus by coming up with new broadly neutralizing antibodies, and also by producing cytotoxic T cells—immune cells that can recognize and destroy infected cells to immobilize the virus. The patient whose HIV response created antibodies for the study has been working with the Rockefeller team for 10 years, contributing his blood serum for their research. He was infected at least three decades ago, and has developed three different types of broadly neutralizing antibodies that bind to three different sites on the virus.

The remarkable thing about his antibodies is that they seem to complement one another’s activity, completely shutting down HIV.

The investigators gave the three antibodies, called BG18, NC37, and BG1, to HIV-infected mice whose immune systems had been modified to more closely resemble those of humans. They found that the trio rendered the virus undetectable in two-thirds of the mice three weeks after it was administered.

“This study validates the approach of using three different antibodies to control HIV infection,” Freund concludes, “pointing the way toward a potential new treatment for people infected with HIV.”

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Atomic-scale view of bacterial proteins offers path to new tuberculosis drugs

Source: Rockefeller University, Newswire
Date: 02/03/17
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With the first detailed analysis of a cellular component from a close relative of the pathogen that causes tuberculosis, Rockefeller scientists are suggesting strategies for new drugs to curb this growing health problem. Each year, nearly half a million people around the world are infected with mutant TB strains capable of evading existing antibiotics.

The research, conducted by a Rockefeller team led by Elizabeth Campbell, in collaboration with scientists at Memorial Sloan Kettering, focuses on a cluster of interacting proteins called RNA polymerase. Crucial to all cells, this protein machine carries out a fundamental process in which genes within the DNA blueprint are copied into RNA. The RNA polymerase is the target of the antibiotic rifampicin—a lynchpin of modern TB treatment, which relies on a combination of drugs. Some bacteria become resistant to rifampicin by acquiring RNA polymerase mutations.

“Now that we can visualize the molecular machinery of the bacteria that the drug targets, we can use a structure-guided approach to better understand how the drug works, how bacteria become resistant to it, and how to potentially improve the drug’s action,” says Campbell, a senior research associate in Seth A. Darst’s Laboratory of Molecular Biophysics. She is one of the senior authors of a report published in the online journal eLife.

A molecular map

To visualize the structure the researchers used an imaging method known as x-ray crystallography. By crystallizing enzymes and other molecules interacting with each other—essentially freezing them in action—investigators are able to see how they fit together, much like keys fitting into locks. This ability to visualize what’s going on can point the way toward more effective drugs, which may be able to latch more securely onto enzymes and other molecules.

“Based on the findings reported in this study,” Campbell says, “we’re already investigating new compounds with new mechanisms of action that appear to inhibit the rifampicin-resistant version of TB. Our eventual goal is to get them into clinical trials investigating new treatments for TB, including rifampicin-resistant TB.”

Rockefeller chemist Sean F. Brady, who was not directly involved in the study, provided the team with these new compounds. He is now working together with Campbell, Darst, and other colleagues to further develop them into antibiotics and characterize the basis of their activity.

Not all bacteria are alike

It’s estimated that up to one-third of the world’s population is infected with M. tuberculosis, the bacterium that causes TB. In the study, the researchers worked with a closely related strain called M. smegmatis. “We needed hundreds of liters of cells to get enough of the material to do the crystallization,” says Elizabeth Hubin, a former Rockefeller graduate student who carried out much of the work. “M. tuberculosis grows too slowly to be able to collect the volume that’s needed, and it’s very dangerous to work with in the lab.”

But M. smegmatis relies on an RNA polymerase that is almost identical in sequence, structure, and behavior to the M. tuberculosis RNA polymerase, which led to another important finding in the study: The RNA polymerase from Escherichia coli, the bacterium most commonly used in lab research, is not. This means there may be a drawback to relying on E. coli as a model when developing certain types of antibiotics for bacteria that cause TB or other diseases.

“Most of the studies previously done with RNA polymerase were done using E. coli,” Campbell says. “We’ve always assumed that the enzyme works the same way in all bacteria, but our study shows we can’t assume what’s found in one bacteria applies to all bacteria.

“Every pathogen needs to be studied individually,” she adds, “so the field has a lot of work to do.”