Fighting Zika Virus with Mosquito Genetics

 

By  John McLaughlin

 

The Zika virus burst into the news last year when a dramatic increase in microcephaly cases was reported throughout several states in Brazil. This frightening birth defect quickly became associated with the mosquito-borne virus, carried by Aedes mosquitos; Aedes aegypti, which also carries Dengue, is the main vector in the current Zika outbreak. While Zika virus usually affects adults with fairly mild symptoms such as fever, rash, and joint pain, it can have severe or fatal consequences for the fetuses being carried by infected females. In fact, The World Health Organization (WHO) has recently reported a scientific consensus on the theory that Zika is the cause of the large number of Brazilian microcephaly cases.

 

In January of 2016, a Hawaiian baby born with microcephaly became the first case of Zika reported in the United States. And the U.S. National Institute of Allergy and Infectious Diseases has recently stated that a wider outbreak of the virus within the United States will likely occur soon. Naturally, mosquito containment has become a top priority for health officials in both infected areas and those likely to be impacted by the virus. The standard list of mosquito control protocols includes pesticide repellents, mosquito nets, eliminating stagnant open water sources, and long-sleeved clothing to limit skin exposure. In addition to these, health authorities are considering a number of new strategies based on genetic engineering technologies.

 

One such technique employs the concept of gene drive, the fact that some “selfish” gene alleles can segregate into gametes at frequencies higher than the expected Mendelian ratios. In this scenario, gene drive can be exploited to spread a disease resistance gene quickly throughout a population of mosquitoes. Recently, a team at the University of California tested this idea by using CRISPR technology to engineer the mosquito Anopheles stephensi with a malarial resistance gene drive. After integration of the resistance gene cassette and DNA targeting with CRISPR, this gene was successfully copied onto the homologous chromosome with high efficiency, thus ensuring that close to 100% of its offspring will bear resistance. Possibly, similar techniques could be exploited to engineer Zika resistance in Aedes mosquitoes.

 

In contrast to engineering disease resistance, an alternative defense strategy is to simply reduce the population of a specific mosquito species, in the case of a Zika outbreak, Aedes aegypti. The WHO has recently approved a GM mosquito which, after breeding, produces offspring that die before reaching adulthood. This technique can dramatically reduce an insect population when applied in strategic locations. The British biotech firm Oxitech has also developed its own strain of sterile Aedes aegypti males. In laboratory testing, these GM mosquitoes compete effectively with wild males for female breeding partners. The short-term goal is receiving approval to test these sterile males in the wild; ultimately, a targeted release of these mosquitoes will reduce the Aedes aegypti population in Zika hot spots without affecting other species.

 

In parallel to mosquito engineering, other work has focused on studying the mechanisms underlying Zika’s dramatic affects on the brain. To study the process of Zika infection in vitro, scientists at Johns Hopkins cultured 3-D printed brain organoids and demonstrated that the virus preferentially infects neural stem cells, resulting in reduced cortical thickness owing to the loss of differentiated neurons. This neural cell death may explain the frequent microcephaly observed in fetuses carried by infected mothers.

 

Much like the recent outbreak of Ebola in several African countries, this event helps underscores the importance of basic research. A recent New York Times article drew attention to this fact by highlighting the need for more complete genome sequences of the mosquito species that carry Zika. With a complete genome sequence at hand, researchers might be able to piece together information in answering questions such as: why are some Aedes mosquitoes vectors for Zika and others aren’t? Species differences in genome sequence may provide some answers. Nevertheless, greater knowledge of the mosquito’s biology will yield more options for human intervention. This is an excellent case study in how ‘basic’ and ‘translational’ research projects can co-evolve in special situations.

 

How Can You Make Money and Help Others with Your Shit?

And other very important poop updates.

 

By Jesica Levingston Mac leod, PhD

First, you have to be a healthy pooper… Second, you have to live in the Boston area. Your stool can help a person suffering from recurrent C. difficile infections, which is a bacterium that affects 500,000 Americans every year.  Where antibiotic treatment has failed to help, a new treatment called “fecal microbiota transplantation” has shown a cure rate of 90%.  In this procedure, a fecal microbiota preparation using stool from a healthy donor is transplanted into the colon of the patient.  OpenBiome, the startup company based in Boston, helps facilitate this procedure by screening and processing fecal microbiota preparations for use in this treatment. After joining the registration you and your stool will be screened and if you are healthy and a good candidate you will became a donor. If you can succeed with all the tests and you can provide “supplies” quite often then you can exchange money for you poo.

Lately, the study of the human microbiota has been all over the news, specially related with weight control, pregnancy and the infant’s diet. In fact, it’s estimated that the human gut contains 100 trillion bacteria, or 10 times as many bacteria as cells in the human body. Yes, I know what you are thinking: “More of them that my own cells, that cannot be right, right?”

These bacteria, or microbiota, influence your health in many ways, from helping to extract energy from food to building the body’s immune system, to protecting against infection with harmful, disease-causing bacteria.

Researchers are only just beginning to understand how differences in the composition of gut bacteria may influence human health. From what we know so far, here are five ways gut flora can affect your wellness:

 

Weight Changes

Yes, your gut bacteria affect your eating disorders (or orders if you are lucky). For example the diversity of gut bacteria is higher in lean people compared to obese people. Also, some specific bacteria groups, the Firmicutes and the Bacteroidetes, are linked with obesity. The famous study were they transplanted gut bacteria from obese and lean people to mice, making the host of the first kind of poo gain more weigh that the mice who received the “lean fecal bacteria”, was a shocking confirmation of the importance of the gut bacteria in the body weight regulation. They discovered that the gut bacteria from obese people increase the production of some amino acids, while the material from lean people increases the metabolism of “burning” carbohydrates.

 

Preterm Labor

Realman and col. found that pregnant women with lower levels of bacteria Lactobacillus in their vagina had an increased risk of preterm labor, compared with women whose vaginal bacterial communities were rich in Lactobacillus. Apparently, the absence of Lactobacillus allows the grown of other species that would have different effects in the pregnancy.

 

Crying Babies

In a funny study on how diet may affect babies, Pertty and col. showed that giving probiotics to your baby does not change the daily crying time, around 173 minutes, compare to the placebo group (174 min), according to the parental diary. They enrolled 30 infants with colic during the first 6 weeks of life.  However, parents reported a decrease of 68% in daily crying in the probiotic and 49% in the placebo group.

 

Heart Attacks

Gut Bacteria produce compounds can even affect your heart. One of these compounds is the trimethylamine-N-oxide (TMAO), and the presence of it in the blood of the subjects of a recent research study, increased 2.5 times the probability of having a heart attack, stroke or to die over a three-year period compared with people with low levels of TMAO. They have also shown that the metabolism of the gut bacteria changes according of the host’s (your) diet. For example, the consumption of high cholesterol and fatty food can increase the bacterial production of TMAO.

 

The Immune System

A recent review published in Cell rang the alarm about the negative effect of the “rich countries” diet in the microbiota influencing the immune system. In ideal and normal conditions the immune system-microbiota association allows the induction of protective responses to pathogens and the maintenance of regulatory pathways involved in the maintenance of tolerance to innocuous antigens. In rich countries, overuse of antibiotics, changes in diet, and elimination of constitutive partners, such as nematodes, may have selected for a microbiota that lack the resilience and diversity required to establish balanced immune responses. This phenomenon is proposed to account for some of the dramatic rise in autoimmune and inflammatory disorders in parts of the world where our symbiotic relationship with the microbiota has been the most affected.

 

Lungs and Asthma

The gut bacteria can affect your lungs: The low levels of 4 gut bacteria strains (FaecalibacteriumLachnospiraVeillonella, and Rothia) in kids was been recently related to an increase in the risk for developing debilitating asthma. The introduction of these 4 bacteria in mice induced to suffered asthma shown protection as the mice’s lungs did not present inflammation.

The question is: how bacteria IN the guts can affect your other tissues and organs? One study that was just published shows  that these bacteria produce chemicals that may help the immune system to battle against other germs. Without this training, the immune system could fail and create inflammation in the lungs. As a follow up from the latest research it may be possible in the near future to predict asthma, and other diseases, as well as cure some illnesses with gut bacteria.

Be ready to give a shit about your shit.

How the Flintstones can Help the Jetsons: History Lessons for Modern Medicine

By Lori Bystrom, PhD

Many of us look forward to a future of convenience with magical gadgets and miracle cures, perhaps something akin to the lifestyle of the cartoon characters on The Jetsons. The show’s optimistic portrayal of the future depicts our fascination with modern technology – an interest that stems not only from our desire for new and improved modes of transportation and communication, but also from our desire for new and better medicine.

 

The future of medicine may seem promising, but understanding the past may be vital for making medical dreams come true. Just as the stone-age characters from The Flinstones are capable of helping the futuristic characters of The Jetsons fix their time machine (see The Jetsons Meet The Flinstones clip from 1:00 to 1:17), so too can our long-departed ancestors help us in ways that will benefit us in the future (perhaps in less barbaric ways than hitting something with a club). In other words, medical advancements, although conventionally based on research using modern technology, can also be derived from medical information of the ancient past.

 

Nowhere is this better exemplified than in the recent discovery of a plant-based eye infection remedy found in a 1,000 year old medical text. This finding was recently presented at the British Society for General Microbiology Annual Conference by researchers at the University of Nottingham in England and Texas Tech University in the United States. They found that the 9th century Anglo-Saxon book, known as Bald’s Leechbook, contained a remedy for an eye infection that consisted of a mixture of garlic, onion or leeks, wine, and bile (from cow’s stomach) that was boiled and fermented in a brass vessel. Amazingly, the recreation of this ancient remedy proved to be effective against the resilient methicillin-resistant Staphylococcus aureus (MRSA), both in vitro and on wounds. In fact, it was found to be more effective than one of the antibiotics (vancomycin) currently used to treat the modern day superbug (see this article). Although clinical trials need to be conducted to confirm the beneficial effects of this medicinal preparation, this is an extraordinary start for a potential drug.

 

Should we be surprised that some of these ancient remedies actually have therapeutic value? Back in the day, when clinical trials did not exist and ethical practices were not necessarily enforced, there was probably a great deal of trial and error as people tried medicines on each other. The only medicines that were recorded were probably those that worked, while ineffective treatments may or may not have been noted. Interestingly, some of the traditional medicines may have been inspired by how animals treated their ailments (an area of study known as zoopharmacognosy). There also may have been minimal repercussions for failed treatments (no lawsuits?), and therefore maybe more freedom for finding medical cures. Moreover, if a treatment was found to be effective nobody probably had to wait for approval from any organization such as the Food and Drug Administration (FDA).

 

Regardless of what happened in the past, it is apparent there are valuable lessons we can learn from our ancestors. For instance, the ancient practice of fecal transplantation is now gaining acceptance in modern medicine. As far back as the 4th century, Ge Hong, a traditional Chinese medicine doctor, used fecal material to treat his patients with food poisoning or severe diarrhea. Just recently, the FDA approved the use of fecal transplants for specific gastrointestinal problems. The use of leeches for the treatment of venous congestion, among other ailments, is another example of modern medicine embracing old technology (see this article). There are numerous conventional medications that also have roots in the distant past (e.g. aspirin). Any book on the history of medicine will provide more information on this subject matter.

 

All of these examples suggest that medical research is limited if it turns a blind eye to the past. Moreover, the medical community needs to address the polar opposite views on traditional/natural medicines: those that think all natural products/traditional remedies are safe and those that think all traditional medicines/natural therapies are inherently bad. What it really comes down to is what is effective and not what resonates better to different patients or doctors. More scientific research needs to assess whether these treatments are safe and effective, while identifying those that may be snake oil. The journalist and information designer, David McCandless, beautifully illustrates some of these differences on his website.

 

Modern medicine should keep an open mind while researchers continue to investigate ancient remedies and screen out the good from the bad. It is appropriate that a small division of the National Institute of Health, known formerly as the National Center for Complementary and Alternative Medicine, was renamed as the National Center for Complementary and Integrative Health. Unconventional or traditional medicines that are effective are not the ‘alternative’, but perhaps the best option or one that can be integrated with other medical treatments.

 

As we move forward in medicine, we might want to keep digging up the past so we are prepared to combat new diseases and improve current treatments. The future of medicine may just need, as George Jetson puts it nicely, “a little stone-age technology.”

Extra Protection: New HPV Vaccine Extends Protection to Nine Strains of The Virus

 

By Asu Erden

The human papillomavirus (HPV) is responsible for 5% of all cancers. Until, 2006 there were no commercially available vaccines against the virus. That year, the Food and Drug Administration (FDA) approved the first preventive HPV vaccine, Gardasil (qHPV). This vaccine conveys protection against strains 6, 11, 16, and 18 of the virus and demonstrates remarkable efficacy. The Centers for Disease Control (CDC) estimates that this quadrivalent vaccine prevents 100% of genital pre-cancers and warts in previously unexposed women and 90% of genital warts and 75% of anal cancers in men. While this qHPV protects against 70% of HPV strains, there remains a number of high-risk strains such as HPV 31, 35, 39, 45, 51, 52, 58 for which we do not yet have prophylactic vaccines.

 

In February of this year, a study by an international team spanning five continents changed this state of affairs. The team led by Dr. Elmar A. Joura, Associate Professor of Gynecology and Obstetrics at the Medical University, published its study in the New England Journal of Medicine. It details a phase 2b-3 clinical study of a novel nine-valent HPV (9vHPV) vaccine that targets the four HPV strains included in Gardasil as well as strains 31, 33, 45, 52, and 58. The 9vHPV vaccine was tested side-by-side with the qHPV vaccine in an international cohort of 14, 215 women. Each participant received three doses of either vaccine, the first on day one, the second dose two months later, and the final dose six months after the first dose. Neither groups differed in their basal health or sexual behavior. This is the immunization regimen currently implemented for the Gardasil vaccine.

 

Blood samples as well as local tissue swabs were collected for analysis of antibody responses and HPV infection, respectively. They revealed the same low percentage of high-grade cervical, vulvar, or vaginal. Antibody responses against the four HPV strains included in the Gardasil vaccine were similar in both treatment groups. Of note is that participants in the 9vHPV vaccine group experienced more mild to moderate adverse events at the site of injection. Dr. Elmar A. Joura explained that these effects are due to the fact that the “[new] vaccine contains more antigen, hence more local reactions are expected. The amount of aluminium [editor’s note: the adjuvant used in the vaccine] was adapted to fit with the amount of antigen. It is the same amount of aluminium as used in the Hepatitis B vaccine.”

 

These results confirm that the novel 9vHPV vaccine raises antibody responses against HPV strains 6, 11, 16, 18 that are as efficacious as the original Gardasil vaccine. In addition, the novel vaccine also raises protection against HPV strains 31, 33, 45, 52, and 58. Importantly, the immune responses triggered by the 9vHPV vaccine are as protective against HPV disease as those raised by the qHPV vaccine.

 

Yet we are all too familiar with the contention surrounding the original qHPV vaccine. And no doubt, this new 9vHPV vaccine will reignite the debate. Those who specifically oppose the HPV vaccine question its safety and usefulness. In terms of its safety, the HPV vaccine has been tested for over a decade prior to becoming commercially available and has been proven completely safe since its introduction a decade ago. Adverse effects include muscle soreness at the site of injection, which is expected for a vaccine delivered into the muscle…

 

As for its usefulness, don’t make me drag the Surgeon General and Elmo onto the stage. The qHPV vaccine has been shown to be safe and to significantly impact HPV-related genital warts, HPV infection, and cervical complications, “as early as three years after the introduction of [the vaccine]” in terms of curtailing the transmission and public health costs of HPV infections and related cancers.   “HPV related disease and cancer is common. It pays off to get vaccinated and even more importantly to protect the children,” noted Dr Elmar A. Joura.

 

Other opponents to the HPV vaccines raise concerns regarding the use of aluminium as the adjuvant in the formulation of the vaccine. This inorganic compound is necessary to increase the immunogenicity of the vaccine and for the appropriate immune response to be raised against HPV. Common vaccines that include this adjuvant include the hepatitis A, hepatitis B, diphtheria-tetanus-pertussis (DTP), Haemophilus influenzae type b, as well as pneumococcal vaccines.

 

The only question we face is that given the availability of Gardasil, why do we need a nine-valent vaccine? In order to achieve even greater levels of protection in the population at large, extending coverage to additional high-risk HPV strains is of central importance for public health. The team of international scientists that contributed to the study underlined that the 9vHPV vaccine “offers the potential to increase overall prevention of cervical cancer from approximately 70% to approximately 90%.” Thus the novel 9vHPV vaccine offers hope in bringing us even closer to achieving this epidemiological goal. “With this vaccine cervical and other HPV-related cancers could potentially get eliminated, if a good coverage could be achieved. This has not only an impact on treatment costs but also on cervical screening algorithms and long-term costs,” highlighted Dr. Elmar A Joura.

Buggy Transportation

All the bugs in the metro, tube, subway, from NYC to Asia

By Jesica Levingston Mac leod, PhD

The New York City (NYC) subway is use for more than 5 million passengers per day. Passengers being humans, pets, bacteria, parasites, viruses and other unknown creatures. Consequently infectious diseases, like influenza can be easily transmitted in this transportation method. Other dangerous circumstances are the black carbon and particle matter concentrations, which In Manhattan are considerably higher than in the urban street level. If you have just ridden the subway, I recommend that you check you washed your hands before continue reading…because, literately, this article is about shit!

Last Month a great research team from Cornell published the studies on microorganisms from 466 subway stations where they found 76 known pathogens (aka “bad” bacteria), and, more interestingly, they found a lot of unknown organisms. This means that almost half of all DNA present on the subway’s surfaces matches no known organism. As they could identified some of the microorganisms, they described that these bacteria were originated in some metropolitan citizen food, pet, workplace… you can actually check which kind of bacteria was found in your favorite/closest subway station… just to be sure what to tell to your doctor next time that you have some infection….

During a year and a half, Dr. Mason, the leader of the group, took samples from materials like the metal handrails in order to collect DNA for the big data genetic metropolitan profile project, aka the Pathomap project. From the 15,152 types of life-forms, almost half of the DNA belonged to bacteria—most of them harmless; However, the scientists said the levels of bacteria they detected pose no public-health problem. The most prevalent bacterial species was Pseudomonas stutzeri, with enrichment in lower Manhattan (aka finance species ;)), followed by strains from Enterobacter and Stenotrophomonas. Notably, all of the most consistently abundant viruses (only 0.03%) were bacteriophages, which were detected concomitant with their bacterial hosts.

Other study done in 2013 in Norway, found that the airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly human passengers) were the major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. The peaks are at 8 am and 5 pm, following the rush hours.

Other great discovery was that the human allele frequencies in the subway mirrored US Census data. Within the neighborhoods they found African American and Yoruban alleles correlation for a mostly black area in Brooklyn, Hispanic/Amerindian alleles in the Bronx and they observed that Midtown Manhattan showed an increase in British, Tuscan, and European alleles.

In this globalized world, you won’t be surprised that in the London’s Tube a group of journalist and researchers found more than 3 million bacteria. These data suggested that the average train or bus seat could have more than 70 types of bacteria, plus cold and flu viruses. The North-South Victoria line was the only one that passed the hygiene test.

In a study at the Hong Kong subways system, researchers analyzed aerosol samples in order to find the taxonomic diversity of the “under” microbes. Each bacterial community within a line was dependent on architectural characteristics, nearby outdoor micro biomes, and distance to other lines, and were influenced by temperature and relative humidity.

Altogether these results sound really scary, but I hope that the reader won’t react panicking, but just being aware of the bad pathogens around him/her and carry a hand sanitizer/mask/cleaning aerosol/wipes or just wash your hands with soap! Actually, health officials from the FDA, believe washing hands with soap and water is the best method to get rid of germs.

Dengue It: Dengue-Specific Immune Response Offers Hope for Vaccine Design

 

By Asu Erden

The dengue virus is a mosquito-borne pathogen that infects between 50 and 100 million people every year. Furthermore, the World Health Organization estimates that approximately half of the global population is at risk. Yet there are currently neither vaccines nor medicines available against this disease, whose symptoms range from mild flu-like illness to severe hemorrhagic fever. The central challenge in designing a vaccine against dengue is that infection can be caused by any of four antigenically related viruses, also called serotypes. Moreover, prior infection with one serotype does not protect against the other three. In fact, such heterotypic exposure can result in much more severe secondary infections – a phenomenon called antibody-dependent enhancement. The lack of knowledge about naturally occurring neutralizing antibodies against dengue viruses has hindered the development of an efficient vaccine. A new study published in the journal Nature Immunology by Professor Screaton’s team at Imperial College, London, may allow the field to overcome this barrier.

 

In this month’s issue of Nature Immunology, Dejnirattisai and colleagues present their characterization of novel antibodies identified from seven hospitalized dengue patients. They first isolated monoclonal antibodies – antibodies made by identical immune cells derived from the same parent cell – from immune cells in the blood of these patients. Among the isolated antibodies, a group emerged that recognized a key component of the dengue virus envelope known as dengue E protein. But unlike previously identified antibodies, this group specifically recognized the envelope dimer epitope (EDE) of dengue, which results from the coming together of two envelope protein subunits on the mature virion rather than a single E protein.

 

The novelty of the study lies in its identification of a novel epitope – EDE – a potent immunogen capable of eliciting highly neutralizing antibodies against dengue. Previously identified antibodies did not show great efficacy against the virus. Antibodies that do not bind dengue antigens sufficiently strongly or are not present at a high enough concentration end up coating the virus through a process named opsonization. This is believed to lead to a more efficient uptake of the virus by immune cells thus fostering a more severe infection by infectious and sometimes also by non-infectious viral particles. This is the issue facing the field. An effective dengue vaccine would have to elicit a potent antibody response able to neutralize the virus while circumventing antibody-dependent enhancement. The antibodies characterized in this study present the peculiarity of efficiently neutralizing dengue virus produced in both insect cells and human cells – both relevant for the lifecycle of the virus – and being fully cross-reactive against the four serotypes.

 

The identification of highly neutralizing antibodies with an efficiency of 80-100%, cross-reactive against the dengue virus serocomplex, and able to bind both partially and fully mature viral particles offers hope for the design of a putative subunit vaccine. Mimicking potent immune responses seen in patients facilitates the process of vaccine development since it removes the need for identifying viral antigens relevant for protection not seen in nature. The naturally occurring responses already point in the right direction. Of the two dengue vaccine trials, neither relied on insight from such immune responses in patients infected with the virus. Based on the present study, it seems that the next step facing the field is to efficiently elicit an immune response that specifically targets EDE. If the antibodies identified here are shown to initiate protection in vivo, Dejnirattisai et al.’s study will have brought the field forward incommensurably.

You Can Help Cure Ebola!

 

By  Jesica Levingston Mac leod, PhD

Since the start of the outbreak last March, Ebola virus has already taken more than 8.000 lives and infected more than 21.200 people, according to the  Center for Disease Control (CDC). The panic raised from this situation rushed the testing of therapies to stop the outbreak and the research on the Ebola virus has seen a rebirth. Some research groups that have been working in this field for a long time can now openly ask for help. One of these groups is the one lead by Dr. Erica Ollman Shaphire at The Scripps Research Institute, California. In 2013 they published in Cell an analysis of the different conformations of Ebola VP40 (Viral Protein 40) aka the shape-shifting “transformer” protein. They reported 3 different conformations of this protein, and how this variety allows it to achieve multiple functions in the viral replication circle. This Ebola virus protein along with the glycoprotein would be used as target for anti viral research. In order to find new anti-virals, their approach is an in-silico scrutiny of thousands of compounds, using viral protein crystal structures in the in silico docking to find leads that may be tested in the lab as inhibitors. IBM is already helping them in this project, generating the World Community Grid to find drugs through the Outsmart Ebola Together project.  Here is where you can start helping, as this project involves a huge amount of data and computing time, they need volunteers that can donate their devices spare computing time (android, computer, kindle fire, etc) to generate a faster virtual supercomputer than can accelerate the discover of new potential drugs. This approach has been shown to be successful for other diseases like HIV and malaria, so you are welcome to join the fight against Ebola virus: https://secure.worldcommunitygrid.org/research/oet1/overview.do.

If you do not have any of these devices (I hope you are enjoying the public library free computers), you can still help Dr. Shapire quest to discover new therapies against Ebola. Her group is now “working to support the salary of a computer scientist to help process the data we are generating with the world community grid” as she describes it. To help identify the most promising drug leads for further testing you can donate money on: www.crowdrise.com/cureebola.

Other groups that were mostly working on other viruses, like Flu, also joined the race to discover efficient therapies. For example, last month, the Emerging Microbes and Infections journal of the Nature Publishing Group published the identification of 53 drugs that are potential inhibitors of the Ebola virus. One of the authors of this paper is Dr. Carles Martínez-Romero, from Dr. Adolfo García-Sastre’s lab in the Department of Microbiology at the Icahn School of Medicine at Mount Sinai. In the study, Dr. Martínez-Romero and collaborators described how they narrowed the search from 2.816 FDA approved compounds to 53 potential antiviral drugs. This high-throughput screening was possible thanks to the use of the Ebola viral-like particle (VLP) entry assay. This allows studying Ebola viral entry without using the ”real”, full replicative virus. These 53 compounds blocked the entry of Ebola VLPs into the cell. Understanding how these market-ready compounds can inhibit Ebola entry and its infectious cycle will pave the way for a new generation of treatments against Ebola virus-associated disease.

Dr. Martínez-Romero had an early interest in science; “Since I was a child, I showed great interest in biological sciences and a great desire to question and discover. This led me to pursue my studies in Biotechnology in order to become a successful researcher.”Viruses are very interesting to me because, although they are not strictly living organisms, they are as old as life itself. Even though they are the origin of many illnesses in mammals and other organisms alike, we are tightly interconnected with viruses and they will continue shaping our evolution throughout the years to come.

I also asked him about advice to his fellow researchers, and he answered: “There is a famous quote of Dr. Albert Einstein: “If we knew what we were doing, it wouldn’t be called Research”. As postdocs and researchers in general, we are constantly pursuing new hypotheses. It is a very arduous path with its ups and downs but full of rewards and new challenges ahead.” About the future of the antiviral research, he keeps a positive view: “Several antiviral therapies are being developed to combat the current Ebola outbreak, such as antibody cocktails (Zmapp), antiviral drugs, and specific Ebola vaccines. Together with re-purposing screens like the one we published, a combination of therapeutic drugs can be used to obtain better antiviral strategies against the Ebola virus.”

Teixobactin: Are We Jumping the Gun on a New Magic Bullet?

 

By Elizabeth Ohneck, PhD

The introduction of penicillin to the clinic in the 1940s ushered in an era of hope in our battle against bacterial disease. Penicillin, produced by a lowly mold, Penicillium notatum, was accidentally stumbled upon by Dr. Alexander Fleming in 1928, when he noticed areas of inhibited bacterial growth around the mold, which had contaminated a petri dish of Staphylococcus aureus. A team of researchers led by Dr. Howard Florey later purified the penicillin compound and developed a method for large-scale production. By 1944, penicillin was being mass-produced and commercial production methods refined. It was a powerful tool during WWII, drastically reducing deaths from infected wounds and surgical procedures. Finally made broadly available to the public in 1945, penicillin was heralded as a “magic bullet,” capable of curing a wide variety of bacterial diseases. For an excellent history of the discovery and development of penicillin, I recommend the book The Mold in Dr. Florey’s Coat: The Story of the Penicillin Miracle, by Eric Lax.

 

Just 4 years later, strains of bacteria resistant to penicillin began to appear, spurring a search for alternatives. Following the penicillin model, researchers turned to other microorganisms for potential antibiotic substances. Soil bacteria provided a rich reservoir for such compounds, leading to the discovery of antibiotics such as streptomycin, erythromycin, and cephalosporins. But carelessness, complacency, and overuse of antibiotics allowed the pathogens to fight back, developing ways to resist these new drugs and landing us in our current predicament, facing dangerous strains of bacteria resistant to almost all available antibiotics, such as MRSA (methicillin-resistant S. aureus), MDR-TB (multi-drug-resistant Mycobacterium tuberculosis), and Neisseria gonorrhoeae. Only a small percentage of soil bacteria – approximately 1% – are able to grow under normal laboratory conditions, and with this reservoir seemingly exhausted, biochemical laboratory synthesis efforts failing, and no new antibiotics in the pipeline, the need for new antibiotic candidates is obvious.

 

One team of researchers decided to go back to the soil. In an exciting paper published in Nature this month, Ling et al. describe the development of a novel method for growing previously uncultivable soil bacteria, leading to the discovery of a new antibiotic they have called teixobactin. To grow the finicky soil bacteria, a sample of soil was diluted and distributed into a multichannel device called an iChip so that each channel contained only one bacterium. The channels were covered with semipermeable membranes to keep the bacteria in but allow exchange of nutrients and growth factors between the channel and the environment. The iChip was then returned to the original soil from which the sample was taken, creating growth conditions highly similar to the bacteria’s native environment. This method increased the number of soil bacteria that could be cultured from 1% to nearly 50%. Even better, once a colony is established in the iChip, many of the bacteria can then be grown in a laboratory setting.

 

The researchers screened extracts from 10,000 isolates obtained by this method for antimicrobial activity against S. aureus and identified a new protein compound produced by the Gram-negative organism Eleftheria terrae, which they named teixobactin. Teixobactin showed potent activity against M. tuberculosis and Gram-positive pathogens such as Clostridium difficile (which causes intestinal infection sometimes referred to as “C. dif”), Bacillus antrhacis (which produces the causative agent of anthrax), and S. aureus, including drug-resistant strains. Unfortunately, it was not effective against Gram-negative bacteria. Teixobactin showed no toxicity against mammalian cells in culture, and effectively cleared S. aureus and Streptococcus pneumoniae infections in mice.

 

Through several biochemical investigations, the researchers determined that teixobactin inhibits production of the bacterial cell wall by binding to highly conserved cell wall building blocks. Without a cell wall, bacterial cells lyse, spilling their essential contents into the environment. Other antibiotics, including penicillin, that inhibit the cell wall target its protein components. One mechanism of antibiotic resistance, known as target modification, results when these protein components, encoded in the bacterial DNA, acquire changes from random DNA mutations that alter the antibiotic target site, preventing antibiotic recognition and action. But teixobactin recognizes a lipid (fat) molecule, suggesting it could be less likely that resistance will develop in this manner. Excitingly, growth of S. aureus and M. tuberculosis on low doses of the drug and passage of S. aureus in the presence of subinhibitory concentrations for 27 days did not result in resistant isolates. In contrast, resistance to the antibiotic ofloxacin began emerging after only 3 days of serial passaging. (Research note: Oflaxacin targets DNA gyrase, an important enzyme in DNA replication and transcription. It would have been nice to see the serial passaging experiment done with penicillin and vancomycin, the antibiotic the researchers compare teixobactin to throughout the paper, as this would have provided control data related to other cell wall targeting antibiotics.) The potent effectiveness, lack of observed toxicity, and failure of immediate resistance development make teixobactin a good candidate for a new antibiotic.

 

These findings have been well celebrated in the media, with the suggestion that teixobactin might be a new “magic bullet”, its “resistance to resistance” finally giving us the upper hand in the battle against antibiotic resistance. It is important to keep in mind, however, that this drug is not effective against Gram-negative bacteria, which have a second membrane that protects the cell wall components which teixobactin targets. Thus, multi-drug resistant strains of pathogens such as E. coli, Pseudomonas aeruginosa, and N. gonorrhoeae are left to wreak havoc in the clinic. More importantly, claims of teixobactin’s “resistance to resistance” are a bit premature. Target modification is only one mechanism by which bacteria can gain antibiotic resistance. Other mechanisms include the acquisition of an enzyme that destroys or modifies the antibiotic, alteration of cell metabolism to avoid use of the product or pathway that the antibiotic targets, changes in cell wall composition or structure that keep the drug out of the cell, or use of an efflux pump, a cellular machine that can recognize and pump out antimicrobial compounds. While some of these mechanisms are more complex and may require exchange of DNA with other bacteria to acquire, all are possible. Development of resistance by serial passaging of a single strain in the lab is much different than within a human patient, where interactions with other pathogens and the normal flora (the bacteria normally found on and in the human body) are plentiful, and the presence of other antimicrobial compounds and alternative nutrient sources create a complex environment that could have significant effects on the development of resistance. There is evidence that genes for antibiotic resistance can be transferred among bacterial species, including those of our normal flora, in vivo.

 

The authors do acknowledge that resistance may develop, but assert that it would likely take several decades, citing the 30 years it took for development of resistance to vancomycin, which works by a mechanism similar to teixobactin, as an example. The comparison of the development of vancomycin resistance to that of other antibiotics, however, isn’t entirely fair. When vancomycin was first introduced, its relatively high toxicity and low efficacy kept it as an antibiotic reserved only for patients with allergies to β-lactams (such as penicillin) or resistant infections. In the early 1980s, as resistance to other antibiotics became more prevalent, vancomycin use spiked, and was followed by the development of resistant strains by 1986. Thus, the case of vancomycin resistance should actually serve as a warning: should teixobactin prove a viable antibiotic, careless overuse will quickly relegate it to the ever-growing pile of ineffective antibiotics.

 

Still, the significance of these findings should not be overlooked or understated. Ling et al. have provided us with the first truly promising antibiotic candidate in many years. Perhaps more importantly, they have developed a method for growing bacteria previously uncultivable in the lab, not only expanding the pool of available antibiotic candidates, but also creating a tool that could prove revolutionary in microbiology, ecology, and environmental research. We should be hopeful that teixobactin is safe and effective in human trials, and that either it can be modified to be effective against Gram-negative pathogens or that the iChip method reveals another compound as potent as teixobactin for their treatment. But we must also be responsible and cautious, so as not to squander these precious new drugs and hasten an era of untreatable bacterial diseases.

 

The Hunt for the Holy Grail: A Potential Vaccine against MRSA

 

By Elizabeth Ohneck, PhD

Vaccines represent the “holy grail” in prevention and treatment of infectious diseases. Effective vaccines have allowed the eradication of small pox and contributed to drastic declines in cases of diseases such as polio, measles, and pertussis (whooping cough). As bacterial pathogens become more resistant to a broader spectrum of antibiotics, the desire to develop vaccines against these offenders to prevent disease altogether heightens.

 

Staphylococcus aureus is a common cause of skin and skin structure infections (SSSIs), as well as post-surgical and wound infections. SSSIs, which frequently present as abscesses in the upper layers of skin tissue, can serve as sources of more serious infections with high mortality rates, such as pneumonia, endocarditis, and bloodstream infections, when the bacteria break through the upper layer of tissue and invade other sites of the body. With the high prevalence of methicillin-resistant S. aureus (MRSA) depleting our antibiotic arsenal, S. aureus infections have become difficult to treat, spurring intense investigation into vaccine development.

 

A group from UCLA recently developed a potential vaccine, NDV-3. This vaccine is actually based on a protein from the fungal pathogen Candida albicans, which causes diseases such as thrush and yeast infections. The C. albicans protein is similar in structure to S. aureus adhesins, proteins on the bacterial surface that allow the bacterial cell to stick to host cells. In preliminary studies, the NDV-3 vaccine was shown to be protective against both C. albicans and S. aureus. In a recent paper in PNAS, Yeaman et al. examine in detail the efficacy of this vaccine in MRSA SSSI and invasive infection.

 

To determine the efficacy of the NDV-3 vaccine in prevention of S. aureus SSSIs, the researchers vaccinated mice with NDV-3, and administered a “booster shot” 21 days later. Two weeks after the booster, the mice were infected with S. aureus by subcutaneous injection, or injection just under the skin, to induce abscess formation. Abscess progression and disease outcomes were then monitored for 2 weeks.

 

Abscess formation was slower and the final size and volume of abscesses were smaller in vaccinated mice compared to control mice. In addition, mice vaccinated with NDV-3 were able to clear S. aureus abscesses by 14 days after infection, whereas abscesses in control mice were not resolved. Using a S. aureus strain expressing luciferase, a protein that emits light, the researchers were able to watch proliferation of the bacteria within the abscesses by measuring the strength of the luciferase signal. Vaccination with NDV-3 resulted in a significantly weaker luciferase signal than in unvaccinated mice, indicating NDV-3 vaccination prevents growth of the bacterial population. This finding was supported by a decrease in the number of CFUs (colony-forming units), an estimate of the number of viable bacteria, isolated from abscesses of vaccinated versus unvaccinated mice. Importantly, the researchers conducted these experiments with 3 distinct MRSA strains and observed similar results for each. Together, these findings demonstrate that while the NDV-3 vaccine does not completely prevent SSSIs under these conditions, vaccination can significantly reduce severity.

 

As skin infections can often serve as a source for more serious disseminated infections, the researchers also examined the effect of NDV-3 on the spread of S. aureus from the original site of infection. While control mice developed small abscesses in deeper tissue layers, vaccinated mice showed little to no invasion of infection. Additionally, significantly fewer bacteria were found in the kidneys of vaccinated mice compared to control mice, indicating NDV-3 can prevent the spread of S. aureus from skin infection to more invasive sites.

 

To examine how NDV-3 was stimulating a protective effect against MRSA, the researchers measured the amount of molecules and cells important for immune response to MRSA in vaccinated and unvaccinated mice. Abscesses of vaccinated mice showed a higher density of CD3+ T-cells and neutrophils, as well increased amounts of the cytokines, or immune cell signaling molecules, IL-17A and IL-22. Vaccinated mice also showed higher amounts of antibodies against NDV-3, as well as increased production of antimicrobial peptides, small proteins with antibiotic activity produced by host cells. Thus, the NDV-3 vaccine helps encourage a strong immune response against MRSA.

 

The NDV-3 vaccine was recently tested in a phase I clinical trial and found to be safe and immunogenic (i.e., stimulates an immune response) in healthy human volunteers. While the vaccine in it’s current form doesn’t prevent S. aureus infections altogether, it could help make infections easier to treat by slowing bacterial growth, preventing spread to other tissues, and boosting the host immune defenses. Further research on this vaccine may also lead to a form that is more protective and can better prevent infections.

 

If Only Santa Would be Real…When Are We Going to Have a Universal Flu Vaccine?

 

By Jesica Levingston Mac leod, PhD

Wouldn’t it be great if the answer to that question was “next year” (yep, only a 1 month wait). Sadly, besides all the astonishing efforts of various researchers groups we are just entering the clinical studies that might lead towards a safe and effective vaccine.

Probably you already heard about the antigenic mismatch with the current vaccine (for the strain H3N2): this means that the strains used in the vaccine could potentially not completely cover one or more of the seasonal influenza virus varieties. Therefore, if you got the flu shot, you might get sick anyways.

The concept behind the universal vaccine is to bypass the antigenic mismatch problem and other issues related with the way in which the vaccines are formulated nowadays. As Drs. Natali Pica and Peter Palese explained last year (Pica et al. 2013), the vaccines are prepared year by year with the aim to protect against the virus strains that are predicted to circulate in the next period. But, and there is always a “but” in predictions, an unexpected mutation in the virus not contemplated in the vaccine production, could conclude in a pandemic.

The clue came from thinking outside of the box, and breaking with the traditional dogmas in flu vaccine production. When you get infected with the influenza virus, your immune system targets the head domain of the HA (Hemagglutinin) protein, so the current vaccine production approach was to aim for this antigen. The bad news is that this domain changes every year. The flu vaccines are based on inactivated viruses , when you receive this vaccine, you will generate antibodies to fight these specific HA proteins. In Dr. Palese’s lab they are focus on regions of influenza HA protein that are highly conserved across virus subtypes, like the stalk domain of the HA protein. Also, he is engineering different HA chimeras. This strategy has been really successful, showing protection in animal models (mice and ferrets), and the vaccines were approved to go to clinical trial next year. This universal vaccine offered good protection for pandemics H5N1 and H7N9 influenza viruses.

Another strategy, published in Nature Medicine (Sridhar et al.) reports that targeting conserved core proteins using virus-specific CD8+ T cells (lymphocytes or white blood cells with a vital role in the immune system) could provide a draft for a universal influenza vaccine. But… even the scientists implicated in the research were not very positive about how long is going to take to translate this technique to the “outside the lab” world.

The third strategy is coming from an Italian group (Vitelli et al. 2013), and this potential universal influenza vaccine is been tested in animal models by the FDA.  This vaccine uses as a vector the virus PanAd3 (it was isolated from a great ape), which carries 2 genes that express proteins conserved among a variety of influenza viruses. The 2 viral proteins, the matrix protein (M1) and the nucleoprotein (NP), could be expressed for the human cells infected with the recombinant PanAd3 virus and immunize the patient against different influenza viruses.

Other entrepreneurial ideas are blooming around the world in order to solver the “influenza virus infection” problem. The influenza virus kills around 500,000 people annually worldwide (WHO), and affects very negatively the life of other hundreds of thousands. In fact, I do not know anybody who did not got the flu at least ones, I encourage to try to find somebody who was never sick with flu symptoms. This points out how universal this problem is and therefore it should get an universal solution soon.