Infante P.,Center for Life Nano Science@Sapienza |
Alfonsi R.,La Sapienza UniversityRome |
Botta B.,University of Rome La Sapienza |
Mori M.,Center for Life Nano Science@Sapienza |
And 3 more authors.
Trends in Pharmacological Sciences | Year: 2015
Hedgehog (Hh) signaling has emerged in recent years as an attractive target for anticancer therapy because its aberrant activation is implicated in several cancers. Major progress has been made in the development of SMOOTHENED (SMO) antagonists, although they have shown several limitations due to downstream SMO pathway activation or the occurrence of drug-resistant SMO mutations. Recently, particular interest has been elicited by the identification of molecules able to hit glioma-associated oncogene (GLI) factors, the final effectors of the Hh pathway, which provide a valid tool to overcome anti-SMO resistance. Here, we review results achieved in developing GLI antagonists, explaining their mechanisms of action and highlighting their therapeutic potential. We also underline the relevance of structural details in their discovery and optimization. © 2015 Elsevier Ltd.
Kuhbacher A.,Pasteur Institute
Journal of visualized experiments : JoVE | Year: 2013
Bacterial intracellular pathogens can be conceived as molecular tools to dissect cellular signaling cascades due to their capacity to exquisitely manipulate and subvert cell functions which are required for the infection of host target tissues. Among these bacterial pathogens, Listeria monocytogenes is a Gram positive microorganism that has been used as a paradigm for intracellular parasitism in the characterization of cellular immune responses, and which has played instrumental roles in the discovery of molecular pathways controlling cytoskeletal and membrane trafficking dynamics. In this article, we describe a robust microscopical assay for the detection of late cellular infection stages of L. monocytogenes based on the fluorescent labeling of InlC, a secreted bacterial protein which accumulates in the cytoplasm of infected cells; this assay can be coupled to automated high-throughput small interfering RNA screens in order to characterize cellular signaling pathways involved in the up- or down-regulation of infection.
The bacteria Pseudomonas aeruginosa and the fungus Aspergillus fumigatus are both opportunistic pathogens often found together in the lung microbiota. When the two pathogens come into direct contact, previous research has shown that the bacteria produces compounds that inhibit fungal growth. Because microbes often produce volatile compounds that can travel through the air, Jean-Paul Latgé Christoph, Heddergott and Benoit Briard, members of the Aspergillus unit at the Pasteur Institute in Paris, wondered if these two pathogens could also communicate via volatile signals. "To our big surprise, volatiles produced by Pseudomonas aeruginosa were promoting the growth of the Aspergillus fumigatus fungus," says Latgé. "Even more surprising, we found that these volatiles were actually taken up by the fungus to support growth." To test how volatile compound signals might travel between and influence the microbes, Heddergott and Briard placed a small Petri dish of Aspergillus to one side inside a larger Petri dish of a Pseudomonas culture. Physically separated by the plastic dishes, the microbes shared common airspace above the dishes' surfaces. "We simply put these two organisms together and in a couple of days, we were surprised to see the fungus growing faster and growing towards the bacteria," says Heddergott. "This really indicated something stimulatory [coming from the bacteria]." To find out what it might be, he used special fibers to absorb the volatile compounds released from each pathogen and then identified them. Heddergott then tested each of the volatiles produced by Pseudomonas individually on the fungus alone. "The most stinky ones containing sulfur stimulated the fungus to grow at the same concentration as co-growing with the bacteria," says Heddergott. He narrowed it down to just one airborne compound mainly responsible for the growth—dimethyl sulfide. Because sulfur is an essential component that Aspergillus needs for growth, the team tested whether dimethyl sulfide was actually being taken up and used as food by the fungus. Heddergott and Briard placed the fungus on a plate of food lacking sulfur, then pumped dimethyl sulfide into the airspace. They showed that the fungus grew better with dimethyl sulfide present and sucked the dimethyl sulfide directly out of the air as fuel. "Before now, no one thought that a fungus could grow on volatile compounds bringing sulfur," says Latgé. In the context of CF lung infections, Latgé says, this might explain why the bacteria usually colonize lungs first and the fungus colonizes later: "When the fungus reaches the patient's lung, having bacteria that are releasing this volatile will help the fungus establish itself." Understanding the relationships between these microorganisms and how they colonize lungs could lead to better ways to prevent these bacterial-fungal co-infections, which are responsible for acute worsening of symptoms and declining lung function in CF patients. "This opens our eyes to look not at just a single organism in human infections, but rather a series of microorganisms," says Latgé. "They can be far away from each other, communicating over a distance, and even using volatile compounds produced by another microbe to grow." Explore further: A feline fungus joins the new species list
Genes inherited from ancient hominins have improved the human immune system. Homo sapiens interbred with Neanderthals and other ancient humans called Denisovans less than 100,000 years ago. Janet Kelso and her team at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, looked for Neanderthal and Denisovan genetic ancestry that has benefited humans by analysing the genomes of hundreds of people from around the world. They found a cluster of three Toll-like receptor (TLR) genes, which are involved in rapidly sensing and responding to infections as part of the innate immune response. Two Neanderthal versions of this cluster and one from Denisovans are common in different human populations. The archaic TLR genes are linked to reduced susceptibility to a bacterial infection of the stomach, but also to higher rates of allergies. In a separate study, a team led by Lluis Quintana-Murci at the Pasteur Institute in Paris identified innate immunity genes that Europeans and Asians seem to have inherited from Neanderthals, including the same cluster of TLR genes.
Francoise Barre-Sinoussi, French virologist and director of the Regulation of Retroviral Infections Division (Unite de Regulation des Infections Retrovirales) at the Institut Pasteur, poses during an interview with Reuters, in Paris, France, October 1, 2015. REUTERS/Philippe Wojazer More PARIS (Reuters) - More than 30 years after she identified one of the most pernicious viruses to infect humankind, Francoise Barre Sinoussi, who shared a Nobel prize for discovering HIV, is hanging up her lab coat and retiring. She's disappointed not to have been able to claim ultimate victory in the battle against the human immunodeficiency virus (HIV) that causes the killer disease AIDS, but also proud that in three decades, the virus has been beaten into check. While a cure for AIDS may or may not be found in her lifetime, the 68-year-old says, achieving "remission" - where infected patients control HIV in their bodies and, crucially, can come off treatment for years - is definitely within reach. "I am personally convinced that remission...is achievable. When? I don't know. But it is feasible," she told Reuters at her laboratory at Paris's Pasteur Institute, where she and her mentor Luc Montagnier discovered HIV in 1983. "We have 'proof of concept'. We have...the famous Visconti patients, treated very early on. Now it is more than 10 years since they stopped their treatment and they are still doing very well, most of them." Sinoussi is referring to a study group of 14 French patients known as the Visconti cohort, who started on antiretroviral treatment within 10 weeks of being infected and stayed on it for an average of three years. A decade after stopping the drugs, the majority have levels of HIV so low they are undetectable. These and other isolated cases of remission, or so-called "functional cure", give hope to the 37 million people worldwide who, due to scientific progress, should now be able to live with, not have their lives cut short by, HIV. In developed countries at least - and in many poorer ones too - an HIV positive diagnosis is no longer an immediate death sentence, since patients can enjoy long, productive lives in decent health by taking antiretroviral drugs to control the virus. It's a long way from the early 1980s, when Sinoussi remembers sick, dying HIV-positive patients coming to the doors of the Pasteur and pleading with scientists there for answers. "They asked us: ‘What we are going to do to cure us’," she says. At that time, she says, she knew relatively little about HIV, but what she was sure of was that these patients would never live long enough to see a treatment developed, let alone a cure. "It was very, very hard." Yet this interaction with real patients, and with their doctors and later their advocates, gave Sinoussi an important insight into what was needed to make her life in science one with meaning and impact -- collaboration. Working across barriers - be they scientific disciplines, cultural, religious and political divides, international borders or gender distinctions, has been and remains Sinoussi's driving force. In her earliest days, feeling disengaged while working on her PhD and itching for action in a real-life laboratory, she hustled her way in to working at the male-dominated Pasteur Institute for free with a virologist researching links between cancers and retroviruses in mice. While viruses are her thing, she has throughout her career worked with, cajoled and learned from immunologists, cancer specialists, experts in diseases of ageing, pharmaceutical companies, AIDS patients, campaigners, and even the pope. "When you work in HIV, it's not only working in HIV, it's working far, far beyond," she said. Freshly armed with her Nobel award and fired up about a lack of support for proven methods of preventing HIV's spread, Sinoussi wrote an open letter to then-Pope Benedict XVI in 2009 criticising him for saying that condoms can promote the spread of AIDS. In what was widely seen as a modification of his stance in response to such criticism, Benedict said in a book a year later that use of condoms could sometimes be justified in certain limited cases as a way to fight AIDS. Sinoussi says: "HIV has shown the way to go in the field of science. You can't be isolated in your laboratory. You need to work with others." And this, she adds, is the "all together" spirit with which she advises her successors to continue after she's gone. Many will be sad to see her leave, but she has faith that her chosen field will deliver for the people who need it. "Of course, I would love to have stopped and to see we had a vaccine against HIV and another treatment that could induce remission – but that's life. I encourage the new generation of scientists today to continue our work. "Science never stops," she says. "Just because a scientist stops, the science should not stop."