R. H. Belmaker, M.D.
Editorial, Am J Psychiatry
Modafinil is a novel compound first approved as a wakefulness-promoting agent in narcolepsy and later found safe and effective in several controlled studies of attention deficit hyperactivity disorder (ADHD). The biochemical mechanism of modafinil is different from that of the usual pharmacological treatments of ADHD, such as amphetamine, which release dopamine. While there are no studies showing modafinil superior to amphetamine or methylphenidate in ADHD or narcolepsy, modafinil seems to have low abuse potential in animal and human studies and is thus more convenient both for the individual clinician and for the health care delivery system. Additional uses for modafinil based on its stimulant properties have been explored in several additional diagnoses.
Bipolar depression is a high-priority research area because of data showing that bipolar patients spend a large portion of their lives in clinically significant depressions and that current treatments are inadequate for the management of these bipolar depressions. A recent study by Sachs et al. (1) in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) found that treatment with sertraline or bupropion as an add-on to a mood stabilizer had no benefit in the treatment of bipolar depression. In this issue of the Journal, Frye et al. now report on a multicenter study of modafinil in bipolar depression. The study randomly assigned 85 patients with bipolar disorder and clinically significant depression despite ongoing treatment with mood stabilizers. Forty-four percent of the patients who were designated to receive modafinil add-on responded within the 6 weeks of the study, and only 23% of those receiving placebo add-on responded, a significant difference.
Previous studies have not found modafinil effective in unipolar depression (2). It is tempting to think that this may reflect a higher prevalence of psychomotor retardation in bipolar depression, which is therefore more responsive to modafinil. However, measures of fatigue and sleepiness did not differ after modafinil and placebo treatment in the study by Frye and associates.
Manic switch was not more common with modafinil than with placebo. However, the mean daily dose of modafinil was only 174 mg (maximum, 200 mg), and studies in narcolepsy and ADHD have sometimes used much higher doses. Patients with past histories of stimulant-induced mania were excluded from the Frye et al. study. The risk of mania in clinical use of modafinil for bipolar depression should be evaluated on the basis of the patient’s past history, especially if dose titration above 200 mg is necessary.
Over one-half of the patients in the study were also taking an antidepressant. While the Sachs et al. study suggested that some antidepressants do little to help bipolar depression (1), other antidepressants not included in the Sachs et al. study have been shown to be effective in bipolar depression, especially antidepressants with more noradrenaline-reuptake-inhibiting properties (3). Therapeutic effects of antidepressants in bipolar depression develop over time, and it is unclear in the article by Frye et al. how many patients receiving antidepressants had been taking these drugs for a long period of time or if they started taking them only 2 weeks before the study.
The response rate of patients in the present study on modafinil was 44%, which the authors point out is similar to response rates in several previous studies of antidepressant treatment of bipolar depression (4). More than half of the patients of Frye et al. were already taking antidepressants and a mood stabilizer. The response rate of about 23% was not different for those receiving antidepressants plus placebo and those receiving placebo only. This could suggest that the present patient group represented antidepressant failures, but the rate is similar to the response rate of about 23% in the study by Sachs et al. (1) for bipolar depressed patients treated with placebo or bupropion or paroxetine. Clearly, there are many differences between patient groups meeting criteria for the diagnosis of bipolar depression.
The present study was double-blind, but all participants, both doctors and patients, knew that it was a study of a new medicine with stimulant-like properties. It is likely that appropriate patients referred to this study were felt by themselves and their physicians to need a stimulant-like compound, perhaps because of fatigue, listlessness, or psychomotor retardation. Patients with prominent agitation or insomnia would be less likely to be referred to or consent to participate in a study where they might receive a stimulant. This could be partially responsible for the positive results.
Often small investigator-initiated studies of new compounds find positive results but larger studies fail to confirm them. It is fairly standard to comment after a small positive study that it should be confirmed in a much larger study. This may not be a universal rule, because in a larger study the investigators might lose the motivation to choose an appropriate subgroup that could be responsive to the compound being tested. It is biologically plausible that modafinil might be useful in some cases of bipolar depression, and the present results in 85 patients support this possibility. A study of perhaps 300 patients might stress the recruitment capacities of the participating centers and lead them to be less discriminating in their choice of patients. This strategy might not lead to definitive further knowledge on the usefulness of modafinil for some bipolar depressed patients.
Does the present study mean that modafinil is the treatment of choice for all bipolar patients with depression? We should avoid assuming that a statistical benefit of one treatment for bipolar depression as a diagnostic entity is relevant for every patient with this heterogeneous condition. The patients in the present study were all taking mood stabilizers. Starting a mood stabilizer would be the first choice for any patient not being so treated. Many of the patients of Frye et al. were taking one mood stabilizer, and Young et al. (5) have shown that adding a second mood stabilizer can often be effective in patients who are having a depressive relapse of bipolar disorder while taking one mood stabilizer. Given that modafinil is an expensive treatment, there well may be bipolar depressed patients for whom appropriate treatment would be a reuptake inhibitor that is also effective on noradrenaline, such as venlafaxine (3).
There have been some preclinical studies of potential wakefulness-inducing treatments that work biochemically by inhibiting the histamine H3 receptor in the brain. However, modafinil has behavioral effects even in mice whose H3 receptor is genetically knocked out (6). It is possible that modafinil is working on the hypocretin system (7), a unique peptide neurotransmitter system that is abnormal in narcolepsy but is unlikely to be a key player in the biochemical mechanism of bipolar depression. Therefore, one could think of modafinil as a nonspecific or symptomatic treatment of bipolar depression. Recent studies have found treatments as diverse as ketamine (8), an anesthetic that antagonizes N-methyl-D-aspartic acid receptors, on the one hand, and exercise (9), on the other hand, to be useful in depression. It may be that a symptomatic rather than a hypothesis-bound mode of thinking is the best way for a clinician to help a patient with bipolar depression. Am J Psychiatry 164:1143-1145, August 2007, doi: 10.1176/appi.ajp.2007.07050749
© 2007 American Psychiatric Association
Science Daily — A human peptide that acts as a natural antibiotic against invading microbes can also bind to the body’s own DNA and trigger an immune response in the absence of an infection, a research team led by scientists at The University of Texas M. D. Anderson Cancer Center reports in an early online publication in Nature.
“This combination of the peptide and self-DNA activates the same immune response pathway as a virus does,” says senior author Michel Gilliet, M.D., assistant professor in M. D. Anderson’s Departments of Immunology and Melanoma Medical Oncology.
Researchers believe this response is both a likely key driver of autoimmune disease and an integral part of an early warning system that flags tissue damage to launch a protective inflammatory response to injury.
“We show that this pathway may drive autoimmunity in psoriasis, a chronic inflammatory skin disease,” Gilliet says. But the key peptide, called both LL37 and CAMP, is also heavily expressed in other autoimmune diseases such as inflammatory bowel disease and rheumatoid arthritis.
LL37 provides a new potential target to block in the treatment of chronic inflammatory diseases and a possible component for vaccines against infectious diseases and cancers, the authors note.
The team tracked down this new pathway by studying the activation of important immune defense cells in psoriasis. Plasmacytoid dendritic cells (pDCs) are highly specialized to recognize viral and other microbial infections. They engulf a virus and set off an immune system cascade to fight the infection by producing interferons.
Gilliet and colleagues previously showed that pDC activation in psoriatic skin drives the development of human psoriasis
“These dendritic cells normally do not respond to self-DNA,” Gilliet explains. This unresponsiveness prevents the cells from launching an attack on the body’s own tissue. However, researchers had accumulated evidence of a connection between skin damage with release of self-DNA and pDC activation in psoriatic skin leading to disease formation. They lacked a molecular mechanism connecting these factors.
In a series of lab experiments, they identified LL37 as the key ingredient in psoriatic tissue that activates the dendritic cells. The peptide is a member of a family of antimicrobial peptides long known to defend against infection through their ability to directly destroy bacteria and viruses.
The team then demonstrated that LL37 activates the dendritic cells by binding to the self-DNA to form a structure that allows it into the dendritic cells, as if it were an invading microbe.
The complex is taken up inside a walled-off chamber in the pDCs called an endosome, where it connects to a sensitive internal receptor that launches production of interferon-alpha, setting off the immune response.
“We think LL37’s normal job is to alert the immune system to tissue damage and stimulate a temporary inflammatory response that enhances resistance to infection and initiates wound healing,” Gilliet says.
“When tissue is injured, cells are destroyed and they spill DNA into the areas surrounding the cells. LL37, released by epithelial cells, binds this extracellular DNA, which is then taken up by the pDCs to launch the protective inflammatory immune response,” Gilliet says.
But in the case of autoimmune disease, LL-37 remains persistently produced, well beyond the temporary jolt needed to dampen infection and promote healing.
Gilliet says follow-up research to better understand the pathway and to exploit it to treat autoimmune disease and cancer is under way.
A grant from the M. D. Anderson Cancer Foundation funded the project, while part of the work was supported by grants from the Deutsche Forschungsmemeinschaft.
Co-authors with Gilliet and first author Roberto Lande are Josh Gregorio, Valeria Facchinetti, Yi-Hong Wang, Wei Cao, Yui-Hsi Wang, Bing Su, Tomasz Zal and Yong-Jun Liu, all of the M. D. Anderson Department of Immunology; Bithi Chatterjee and Ira Mellman, both of Yale University and Genentech; Frank O. Nestle, of King’s College London School of Medicine; Bernhard Homey of Heinrich-Heine University of Dusseldorf, Germany; and Jens-Michael Schröder of University Hospital Schlewsig-Holstein, University of Kiel, Germany.
This story has been adapted from a news release issued by University of Texas M. D. Anderson Cancer Center.
ACuRay sensor chip developed by Georgia Tech researchers for early detection of cancer. (Credit: AACR)
Georgia Institute of Technology – Cancer-sensing devices built as cheaply and efficiently as wristwatches — using many of the same operating principles — could change the way clinicians detect, treat and monitor cancer in patients.
Researchers from the Georgia Institute of Technology have created an acoustic sensor that can report the presence of small amounts of mesothelin, a molecule associated with a number of cancers including mesothelioma, as they attach to the sensor’s surface.
According to the researchers, the study is a proof of principle, demonstrating a technique that might work for the detection of nearly any biomarker — a collective term for a molecular signal that denotes the presence of disease.
“It is one thing to be able to identify biomarkers for a disease, but it is another to be able to find them in blood quickly and easily at very low concentrations,” said Anthony Dickherber, a graduate student in the School of Electrical and Computer Engineering at Georgia Tech. “We envision that, one day, doctors can use an array of our sensors as a sort of laboratory in their office, where they could use a quick blood sample to detect or monitor the signs of cancer.”
According to Christopher Corso, the other graduate student engaged in the project and an M.D., Ph.D. student, such a device would be a boon to healthcare practice, allowing physicians to screen patients for signs of disease before opting for more expensive or invasive diagnostic techniques.
Responding to the growing need for such sensors in both research and clinical practice, Dickherber, Corso and research adviser William D. Hunt, Ph.D., conceived of and developed the ACuRay™ chip, standing for ACoustic micro-arRay — a device that shares more in common with an inexpensive wristwatch than the sort of cutting edge molecule-sorting apparatuses currently used by researchers and clinical laboratory technicians.
The array consists of a series of electrodes deposited on the surface of a thin film of zinc oxide, which allows the device to resonate, or vibrate, at a specific frequency when a current is applied, much like the quartz timing devices used in many clocks and watches.
“The sensor itself is built on a base of silicon, like a computer chip, and could be mass-produced using very well known and inexpensive microelectronic fabrication techniques,” Dickherber said.
To turn this array into a sensor, the Georgia Tech researchers coated the zinc oxide surface with mesothelin-specific antibodies generated in the lab of Ira Pastan, M.D., at the National Cancer Institute. These molecules are engineered versions of the antibodies the immune system creates to identify foreign intruders, such as microbial parasites. In this study, the researchers coated the sensor with antibodies for mesothelin, a cell-surface protein that is highly expressed in mesothelioma, ovarian cancer, pancreatic cancer and other malignancies.
When the mesothelin binds to an antibody, the added mass changes the frequency at which the acoustic wave passes between the electrodes on the surface of the device. The device is able to “hear” the pitch change due to nanomolar concentrations of mesothelin (just a few molecules amid billions) binding to antibodies on the chip. The technology has the potential of detecting biomarkers in even lower concentrations than those tested, Dickherber said.
“It is really an elegant engineering solution to a very complicated problem,” said Hunt, a professor of electrical and computer at Georgia Tech and lead researcher on the project. “We could, for example, detect a number of different markers for a single disease on a single chip no bigger than the tip of a fountain pen. With refinement, this technology could readily lead to an inexpensive, ubiquitous technology for researchers, physicians and the clinical laboratory.”
The researchers recently presented their findings in Atlanta, Georgia at the American Association for Cancer Research’s second International Conference on Molecular Diagnostics in Cancer Therapeutic Development.
This research is supported by grants from the U.S. Army Medical Research & Materiel Command Prostate Cancer Research Program, the National Science Foundation, The V Foundation, the National Cancer Institute and the Georgia Cancer Coalition.
Note: This story has been adapted from a news release issued by American Association for Cancer Research.
Matthew Herper, 09.24.07
You wouldn’t know it from the lack of fanfare, but the Food and Drug Administration is getting its biggest overhaul in a decade in a dramatic coda to Merck’s withdrawal of the blockbuster painkiller Vioxx three years ago.
A bill to give the FDA more power passed both houses of Congress with only a handful of no votes, and the president is expected to sign it into law. Because the bill is attached to the re-authorization of an important part of the FDA’s funding, a veto is unlikely. If the law doesn’t pass soon, FDA head Andrew Von Eschenbach is going to have to start informing staffers that their jobs are no longer funded.
The bill represents a victory for advocates of higher standards for making sure that drug side effects are known and promptly dealt with. Before Vioxx was yanked, some of the changes being made would be unimaginable. Until now the claims drug companies like Merck and Pfizer made about their medicines were, to a degree, negotiated. Labeling discussions between Merck and the FDA dragged on, and as a result, the agency will now be able to dictate what claims companies can make with much more force.
Another change: The FDA will be able to force drug makers to do clinical trials even after a medicine is approved and fine them if they don’t follow through. Previously, many big clinical trials regulators asked for weren’t finished. And there will be more money to study side effects of new medicines post-approval. Companies will pay more in fees when they submit drug applications, increasing the amount of money the FDA gets from industry by 25% to $400 million.
One of the farthest-reaching changes may be a new requirement demanding that the drug companies list all of their clinical trials in a registry maintained by the National Institutes of Health accessible to anyone with an Internet browser. After the studies finish, the results will also have to be posted. This will expose drug companies to new levels of scrutiny about the safety of their medicines. (See: Lynch ‘Em)
Rough-and-ready analyses of existing data set off the Vioxx controversy and the recent kerfluffle over the diabetes drug Avandia. Such analyses, where researchers try to combine different studies to get a better idea of what kinds of side effects emerge in incredibly large groups, also linked antidepressants like GlaxoSmithKline’s Paxil to suicide risk and the Johnson & Johnson heart failure medicine Natrecor to kidney problems. In both cases, there are still debates about how real the risks are, but they put a squeeze on sales.
Lots of stuff didn’t go into the bill. The Union of Concerned Scientists, while lauding the bill, worried that it didn’t do enough to deal with the financial conflicts of FDA advisers. It appears to only increase the FDA’s power to regulate direct-to-consumer ads a little bit. Pharmaceutical companies had at one point hoped that the bill would contain language that helped protect products that had been vetted by the FDA from product liability suits.
At one point, it looked as if the bill might address how the FDA should go about approving cheaper copycat versions of biotech protein drugs like insulin and human growth hormone. Right now, there’s no mechanism for approving true generics of these products, which can be extremely expensive. Part of the reason: Complex safety issues arise because proteins are far more difficult to manufacture than the simpler chemicals in pills like Vioxx and Lipitor.
But all of these issues were Johnny-come-latelies to the Congressional debate. The focus was creating a more transparent FDA with the power to better study and regulate drug safety. Legislators were probably smart, in the end, to stick with the issues they had debated the most and approve a bill that is uncontroversial now but would have seemed like a radical step three years ago.
Hopefully, the changes will strengthen the FDA, renewing the public’s shaken faith in the safety of medicines. Drug makers could wish for nothing more.
Science Daily — Researchers report that fasting or eating half as much as usual every other day may shrink your fat cells and boost mechanisms that break down fats.
Consuming less calories and increasing physical activity is usually what people do to lose weight and stay healthy. But some people prefer to adopt a diet which consists of eating as much as they want one day while fasting the next. On each fasting day, these people consume energy-free beverages, tea, coffee, and sugar-free gum and they drink as much water as they need.
Although many people claim that this diet, called alternate-day fasting (ADF), help them lose weight and improved their health, the effects on health and disease risk of ADF are not clear.
Krista Varady and colleagues studied the effects of alternate-day fasting on 24 male mice for four weeks. To assess the impact of ADF on the health of the mice, the scientists not only tested mice that followed and didn’t follow an ADF diet, but they also studied mice that followed the diet only partially: a group of mice consumed 50 percent of their regular diet every other day (ADF-50%) and another consumed 75 percent of their regular diet every other day (ADF-25%).
The scientists noticed that the ADF-100% mice lost weight and the fat cells of both the ADF-100% and ADF-50% groups shrunk by more than half and by 35 percent, respectively. Also, in these two groups of mice, fat under the skin — but not abdominal fat — was broken down more than in mice that did not follow the diet.
These results suggest that complete and modified ADF regimens seem to protect against obesity and type 2 diabetes but do not result in fat or weight loss. More studies will be needed to confirm whether the long-term effects of ADF regimens are beneficial for health and reduce disease risk, the scientists conclude.
Article: “Effects of modified alternate-day fasting regimens on adipocyte size, triglyceride metabolism and plasma adiponectin levels in mice,” by Krista A. Varady, D. J. Roohk, Y. C. Loe, B. K. McEvoy-Hein, and M. K. Hellerstein
Note: This story has been adapted from a news release issued by American Society for Biochemistry and Molecular Biology.
Science Daily — Administering hydrogen sulfide (H2S) directly into the heart during a simulated heart attack significantly reduces the tissue and cell damage often seen in oxygen-starved organs, according to a new study from researchers at the University of Alabama at Birmingham.
H2S boosts post-heart-attack function by helping to minimize reperfusion injury, an unwanted side effect of restoring blood flow swiftly to hearts suffering from low oxygen, the study authors said.
In testing on mice, the H2S injection led to a 72 percent reduction in the amount of severe heart-tissue death after restoring normal oxygen and blood flow to mice hearts. The 72 percent reduction compares to a much larger average amount of tissue death in un-treated mice hearts after the same 30 minutes of oxygen deprivation.
Findings on the protective qualities of H2S have broad implications for improving human survival after cardiac arrest, heart transplant and trauma in general, said David Kraus, Ph.D., a UAB associate professor in the Departments of Environmental Health Sciences and Biology and co-author on the new study.
“One of the most damaging biological stresses on the heart and other organs from trauma or transplantation is the rapid change in oxygen levels,” Kraus said. “First there’s a drop, which elicits a dramatic cellular adjustment to survive low oxygen, and then a rapid rise caused by resuscitation.
“H2S as an internal bodily signal appears to serve as an important protective mechanism during the stress of low oxygen availability,” he said.
The UAB researchers worked with a team led by David Lefer, Ph.D. from the Albert Einstein College of Medicine in Bronx, N.Y.
The tests were done by injecting H2S directly into the hearts of mice who had been anesthetized for surgery, and whose left ventricular artery had been clamped for 30 minutes to simulate a heart attack.
In addition to a decrease in heart-tissue death, H2S-treated mice hearts showed a 35 percent drop in blood-protein levels that signal myocardial damage, and a 26 percent drop in heart-tissue markers of inflammation when compared to un-treated mice hearts.
Furthermore, by isolating mitochondria from the H2S-treated mice, the authors confirmed that heart-cell functional integrity had been preserved. Recent reports from other researchers demonstrate that inhaled H2S can induce a fully reversible “suspended animation” state in animals.
Kraus said it follows that H2S could be used to place organs into “suspended animation” before surgery or during medical transport until normal oxygen and blood flow is restored. Also, by augmenting internal H2S production in the body, perhaps through diet, people may reduce their risks of cardiovascular disease, chronic oxidative cell damage and other illnesses, Kraus said.
H2S is normally considered a toxic, flammable gas that is responsible for the foul odor of rotten eggs. But in the UAB study it was carefully formulated into a low concentration saline-type solution.
The study was published Sept. 18 in the online Early Edition of the journal Proceedings of the National Academy of Sciences. It also included researchers at Thomas Jefferson University in Philadelphia, the University of Medicine and Dentistry of New Jersey and the National Institute of Neuroscience in Tokyo, Japan. Grant support came from the National Institutes of Health, the American Diabetes Association, the American Heart Association and from Ikaria Inc. in Seattle, Wash. This story has been adapted from a news release issued by University of Alabama at Birmingham.
Bacteria that was sent into space on the shuttle came back to Earth genetically altered and significantly deadlier.
Salmonella, the bacterium that causes food poisoning, was sent in special test tubes as a payload on the space shuttle Atlantis in September 2006. When it returned, scientists found the bugs were three times more deadly to laboratory mice than the same germs grown in identical containers and at the same temperature and humidity as on the spacecraft.
Researcher James Wilson, lead author of a report on the phenomenon in Tuesday’s edition of the Proceedings of the National Academy of Sciences, said the bacteria grown in space showed altered protein production arising from 167 of their estimated 4,000 genes, which made them far more virulent than their Earth-bound counterparts.
After the shuttle touched down on terra firma 12 days later, the researchers gave lab mice varying doses of the salmonella. After 25 days, 40 per cent of the animals given bacteria that had stayed home were still alive, compared with only 10 per cent of rodents given the space-travelling germs.
Furthermore, Wilson said, it took about one-third as much of the bacteria from the orbiting shuttle to kill half the mice, compared with the salmonella on Earth.
So what is it about space that so alters bacteria and what does that mean for astronauts or future space travellers?
“The answer is we don’t know, ” Wilson, a research assistant professor at the Biodesign Institute at Arizona State University, said Monday from Tempe, Ariz.
But he believes the bacteria reacted to what’s called “low fluid shear,” caused by microgravity’s effect on the liquid inside the test tubes aboard the space vehicle.
When new salmonella cells grow in microgravity, the force of the liquid passing over the cells is reduced, likely causing them to change, said Wilson.
That fluid shear effect also occurs in humans, in certain areas of the gastrointestinal tract, where salmonella can take up residence and cause illness, he noted.
“A major goal of the study was to see how space flight affects a bacteria and particularly a pathogen, because those pathogens (disease-causing germs) will be up there with astronauts. With all the quality control we do and efforts to prevent that, it will happen.”
“We do want to apply the results we have here to crew safety,” he said. “And seeing how these changes affect their (bacteria’s) ability to cause disease, we can also use that information to fight infections here on Earth.”
“So this is not just space-type stuff. It does also help humankind on Earth as well.”
Microorganisms may soon be efficiently and inexpensively producing novel pharmaceutical compounds, such as flavonoids, that fight aging, cancer or obesity, as well as high-value chemicals, as the result of research being conducted by University at Buffalo researchers.
In work that could transform radically the ways in which many of these compounds are produced commercially, the UB researchers are genetically engineering microorganisms, such as E. coli, into tiny, cellular factories.
Several patents related to this work have been filed by UB. The team also is in discussions with companies in the U.S. and abroad.
First Wave Technologies, Inc., a technology development company based in UB’s New York State Center of Excellence in Bioinformatics and Life Sciences, which is collaborating with the UB group, recently received a highly competitive Phase I Small Business Innovation Research (SBIR) grant from the National Science Foundation to focus on the biosynthesis of a popular group of flavonoids called isoflavonoids.
“Ultimately, we want to be able to take a designed E. coli off of the shelf and drop into it the enzymes that constitute a particular biosynthetic pathway in order to make exactly the product we want,” said Mattheos A. G. Koffas, Ph.D., assistant professor of chemical and biological engineering in the School of Engineering and Applied Sciences and leader of the UB team.
The UB approach to synthetic chemistry addresses some of the major challenges in conventional industrial production of specialty chemicals.
Through the use of specially adapted bacteria, specialized enzymes and natural feedstocks, microbial biosynthesis reduces or eliminates the need for petrochemical sources, elevated temperatures, toxic heavy metal catalysts, extremes of acidity and dangerous solvents, Koffas said.
In addition, the natural enzymes the UB researchers are using can facilitate chemical reactions that are difficult to accomplish through conventional chemistry, such as chiral synthesis, glycosylations and targeted hydroxylations, common but challenging steps in many syntheses.
“We are finding out how we can actually ‘train’ microbial systems to produce high yields of chemicals to be used as pharmaceuticals and to make production processes more efficient, less expensive and more environmentally friendly,” Koffas said.
As with any commercial endeavor, process efficiency is a critical concern, he noted.
In work published in Applied and Environmental Microbiology in June, Koffas and his colleagues produced about 400 milligrams of flavonoids per liter of cell culture, far above the next highest yield of about 20 milligrams per liter produced by other microbial synthesis efforts.
“We have done this by increasing the amount of precursor available and re-engineering the native microbial metabolism,” he explained, adding that they have taken different approaches to identifying the pathways that lead to the biosynthesis of precursors for desired compounds.
“Further improvement of production yields are possible and various approaches are being pursued by our team at this time,” he said.
Another major challenge for microbial biosynthesis is that the enzymes required for certain chemical steps have special requirements that the host cell cannot meet efficiently, Koffas said. In some cases, the enzyme needs to be re-engineered, while in others the host cell needs modification.
Koffas’ lab recently achieved the functional expression in E. coli of P450 monooxygenases, enzymes that are used widely in nature, but are not readily expressed in most industrially important microorganisms.
“P450 is very important in the synthesis of natural products,” said Koffas. “For example, both Taxol, the breast cancer drug that is currently produced from plant cultures, and artemisinin, the anti-malaria drug, have P450 enzymes in their biosynthetic pathways.”
The Koffas lab has introduced ways to modify both the P450 monooxygenase enzymes and the host cell, thereby improving their yield of flavonoids.
Microbial biosynthesis methods also are making it easier to create analogs of existing drugs, as well as new molecules for a broad range of therapeutics.
The UB researchers are particularly interested in developing novel molecules that can be used to treat chronic diseases, such as type II diabetes and obesity.
They also are using the methods to produce specialty compounds, such as natural pigments, that could replace chemical dyes in food.
Koffas’ goal is to employ these microbial synthesis methods for a wide variety of applications.
Flavonoids, which are of interest to pharmaceutical companies because of their antioxidant and anti-carcinogenic properties, are difficult to produce using currently available methods.
Microbial synthesis strategies also are being adapted by the UB researchers for the biosynthesis of other commercially significant classes of compounds, including vitamins, anti-cancer drugs, anti-parasitic drugs, dyes and food supplements.
The UB group is working on boosting yields further and hopes to achieve pilot scale production of flavonoids by the end of this year.
For further information on commercialization of this technology, you may contact Mike Fowler, commercialization manager for bioinformatics and health sciences, in UB’s Office of Science, Technology Transfer and Economic Outreach.
Koffas’s research has received funding from the National Science Foundation, UB’s New York State Center of Excellence in Bioinformatics and Life Sciences and the Independent Research and Development Fund of the UB Office of the Vice President of Research.
This story has been adapted from a news release issued by University at Buffalo.
Investigators at the University of British Columbia, have found a way to turn on the brakes of a cell, and thus halt abnormal blood-cell growth in a range of 1) ___ and autoimmune disorders, and blood cancers. The immune system relies on white blood cells called, 2) ___, to defend the body against infectious pathogens such as bacteria and viruses. In a healthy body, leukocytes are strictly controlled and turned off when no longer needed. This off-switch is controlled by a 3) ___ called “SHIP” – standing for SH2-containing inositol 5’phosphatase. SHIP, which is only present in 4) ___ cells, was discovered in 1997 by, a senior scientist at the BC Cancer Research Center. It regulates the PI3 kinase (PI3K) pathway which is essential for cell growth, survival and 5) ___ cell activation. Inappropriate or persistent activation of the PI3K pathway, can result in serious inflammatory/immune diseases or blood cancers such as multiple 6) ___, leukemia and lymphoma. Aiming to find new drugs for treatment of blood borne diseases, a team searched for drugs that could modulate SHIP. The team screened a library of sea sponge extracts for molecule compounds that can turn SHIP on. Sea sponges are a rich source of novel bio-active 7) ___, created by nature, to protect themselves against marine predators. Interestingly, many of these compounds possess important medicinal properties. The sponge library has already produced other agents with interesting biological properties on 8) ___ cells, some of which are in clinical development as potential drugs for treatment of human diseases. The researchers identified a compound, now known as AQX-MN100. It is able to inhibit immune and blood cell activation both in the test tube and in mouse models of human inflammatory disease and lymphoma by activating SHIP. This is an entirely new paradigm for controlling run-away cells. Previous research efforts were aimed at trying to control the cells through blocking stimulation 9) ___. In a run-away train analogy, this would be like taking your foot off the accelerator and the train will eventually stop when it runs out of fuel vs. this new approach of directly applying the brakes. Since SHIP is only found in 10) ___/___ cells, side-effects of SHIP-based therapy on other cells of the body, are expected to be limited. The AQX-MN100 discovery has been validated by proof-of-principal grants from the Canadian Institutes of Health Research (CIHR) aimed at translating basic research findings into clinically applicable therapy. This research is highlighted in the Sept. 15 edition of Blood, Journal of the American Society of Hematology.
ANSWERS: 1) inflammatory; 2) leukocytes; 3) protein; 4) blood; 5) immune; 6) myeloma; 7) compounds; 8) mammalian; 9) signals; 10) immune/blood