Researchers discover a critical cellular “off” switch for the inflammatory immune response that causes asthma attacks
Working with human immune cells in the laboratory, Johns Hopkins researchers report they have identified a critical cellular “off” switch for the inflammatory immune response that contributes to lung-constricting asthma attacks. The switch, they say, is composed of regulatory proteins that control an immune signaling pathway in cells.
“Asthma patients are constantly firing through this pathway because those proteins are stuck in the ‘on’ position, without proper control by other proteins that shut down this reaction,” says Nicola Heller, Ph.D., assistant professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine.
Asthma has been correlated with an overabundance of one type of immune cell called M2 macrophages in the lungs. In a nonasthmatic person, the M2 macrophages activate to clean up inhaled allergens and foreign particles, and then deactivate when the irritant is broken down.
However, in people with asthma, the M2 cells and the chemical signals they emit linger and call in other cells that cause inflammation that can trigger an asthma attack with the classic symptoms of difficulty breathing, wheezing and shortness of breath. Over time, the lung is changed by secretions from the M2 cells, which cause the lung tissue to remodel itself, contributing to irreversible obstruction and poor lung function. “If you prevent these cells from becoming the M2 type, you can potentially stop the continued inflammation and long-term structural changes,” says Heller.
The new research, reported Nov. 25 in the Journal of Biological Chemistry, investigated the role of two proteins, GRB10 and p70S6K, in the control of the signaling pathway that activates M2 cells.
In their previous work, also published in the Journal of Biological Chemistry Sept. 23, Heller’s group found that the inflammatory pathway involving the two proteins begins with interleukin 4 (IL-4), an immune system chemical that passes through a protein named IRS-2 before activating the M2 cells. They found that other proteins that stop the action of IRS-2 were not present in human M2 cells from people with allergies compared to healthy people. This made IRS-2 more active and increased the formation of M2 cells in people with allergies.
In the new study, Heller’s lab delved deeper into the IRS-2 pathway. By analyzing chemical changes of the IRS-2 protein in immortalized cultures of human white blood cells, it determined that IRS-2 appeared in two different forms — “on,” which allows the signal to pass through, and “off,” which stops the signal from activating the cells into M2 macrophages. They began by observing which proteins became active in the presence of IL-4 in human white blood cells and add “stop” signals to IRS-2. The activity of two regulatory proteins, GRB10 and p70S6K, increased after IL-4 exposure compared to the same cells that were not exposed to IL-4.
In further test tube experiments, the researchers treated the immortalized white blood cells with both chemical and genetic blockers, called small interfering RNA (siRNA), designed to render either p70S6K or GRB10 nonfunctional. The researchers saw that decreased GRB10 and p70S6K activity resulted in more of the “on” form of IRS-2, meaning these proteins are responsible for turning off IRS-2 and thereby downstream M2 production.
“This confirmed for us that without properly functioning GRB10 and p70S6K, the cells could not turn off IRS-2 signaling and M2 production,” says Heller.
The research team, Heller says, has already begun experiments to further explore the implications of these results, which include looking at differences in this pathway between cells taken from allergic and healthy individuals, and testing the efficacy of an inhalable drug that mimics the function of GRB1 and p70S6K to shut off the development of M2 macrophages in the lungs of mice. “One of the advantages of working with lung macrophages is that they are one of the first cells that see anything that gets put in an inhaler,” says Heller. “So we hope to modulate their activity in this way.”
These findings also have implications for treatment of cancer and other disorders, such as obesity, in which M2 macrophage cells play a regulatory role in tumor growth and fat deposition.
Learn more: Turning off Asthma Attacks
In a small double-blind study, Johns Hopkins researchers report that a substantial majority of people suffering cancer-related anxiety or depression found considerable relief for up to six months from a single large dose of psilocybin — the active compound in hallucinogenic “magic mushrooms.”
The researchers cautioned that the drug was given in tightly controlled conditions in the presence of two clinically trained monitors and said they do not recommend use of the compound outside of such a research or patient care setting.
The Johns Hopkins team released its study results, involving 51 adult patients, concurrently with researchers from New York University Langone Medical Center, who conducted a similarly designed study on 29 participants. Both studies are published in the Journal of Psychopharmacology on Dec. 1.
The Johns Hopkins group reported that psilocybin decreased clinician- and patient-rated depressed mood, anxiety and death anxiety, and increased quality of life, life meaning and optimism. Six months after the final session of treatment, about 80 percent of participants continued to show clinically significant decreases in depressed mood and anxiety, with about 60 percent showing symptom remission into the normal range. Eighty-three percent reported increases in well-being or life satisfaction. Some 67 percent of participants reported the experience as one of the top five meaningful experiences in their lives, and about 70 percent reported the experience as one of the top five spiritually significant lifetime events.
“The most interesting and remarkable finding is that a single dose of psilocybin, which lasts four to six hours, produced enduring decreases in depression and anxiety symptoms, and this may represent a fascinating new model for treating some psychiatric conditions,” says Roland Griffiths, Ph.D., professor of behavioral biology in the Departments of Psychiatry and Behavioral Sciences and of Neuroscience at the Johns Hopkins University School of Medicine. He notes that traditional psychotherapy offered to people with cancer, including behavioral therapy and antidepressants, can take weeks or even months, isn’t always effective, and in the case of some drugs, such as benzodiazepines, may have addictive and other troubling side effects.
Griffiths says his team’s new study grew out of a decade of research at Johns Hopkins on the effects of psilocybin in healthy volunteers, which found that psilocybin can consistently produce positive changes in mood, behavior and spirituality when administered to carefully screened and prepared participants. The study was designed to see if psilocybin could produce similar results in psychologically distressed cancer patients.
“A life-threatening cancer diagnosis can be psychologically challenging, with anxiety and depression as very common symptoms,” says Griffiths. “People with this kind of existential anxiety often feel hopeless and are worried about the meaning of life and what happens upon death.”
For the study, the investigators recruited 51 participants diagnosed with life-threatening cancers, most of which were recurrent or metastatic. They were chosen from a total of 566 individuals reached through flyers, web advertisements and physician referrals. Most participants had breast, upper digestive, GI, genitourinary or blood cancer, and each had been given a formal psychiatric diagnosis, including an anxiety or depressive disorder.
Half of the participants were female with an average age of 56. Ninety-two percent were white, 4 percent were African-American and 2 percent were Asian.
Each participant had two treatment sessions scheduled five weeks apart, one with a very low psilocybin dose (1 or3 milligrams per 70 kilograms) taken in a capsule and meant to act as a “control” placebo because the dose was too low to produce effects. In the other session, participants received a capsule with what is considered a moderate or high dose (22 or 30 milligrams per 70 kilograms).
To minimize expectancy effects, the participants and the staff members supervising the sessions were told that the participants would receive psilocybin on both sessions, but they did not know that all participants would receive one high and one low dose. Blood pressure and mood were monitored throughout the sessions. Two monitors aided participants during each session, encouraging them to lie down, wear an eye mask, listen to music through headphones and direct their attention on their inner experience. If anxiety or confusion arose, the monitors provided reassurance to the participants.
In addition to experiencing changes in visual perception, emotions and thinking, most participants reported experiences of psychological insight and often profound, deeply meaningful experiences of the interconnectedness of all people.
The researchers assessed each participant’s mood, attitude about life, behaviors and spirituality with questionnaires and structured interviews before the first session, seven hours after taking the psilocybin, five weeks after each session and six months after the second session. Immediately after the sessions, participants completed questionnaires assessing changes in visual, auditory and body perceptions; feelings of transcendence; changes in mood; and more.
Structured clinical interviews, such as the Hamilton Depression Rating Scale and the Hamilton Anxiety Rating Scale, and patient questionnaires, like the Beck Depression Inventory and the State-Trait Anxiety Inventory, assessed depression and anxiety. Other questionnaires assessed quality of life, death acceptance, meaningful existence, optimism and spirituality — generally defined as a search for the meaning of life and a connection to something bigger than one’s self. To measure the changes in attitudes, moods and behavior over time, the researchers administered a questionnaire that assessed negative or positive changes in attitudes about life, mood and behavior.
With regard to adverse effects, Griffiths says 15 percent of participants were nauseated or vomited, and one-third of participants experienced some psychological discomfort, such as anxiety or paranoia, after taking the higher dose. One-third of the participants had transient increases in blood pressure. A few participants reported headaches following the session.
“Before beginning the study, it wasn’t clear to me that this treatment would be helpful, since cancer patients may experience profound hopelessness in response to their diagnosis, which is often followed by multiple surgeries and prolonged chemotherapy,” says Griffiths. “I could imagine that cancer patients would receive psilocybin, look into the existential void and come out even more fearful. However, the positive changes in attitudes, moods and behavior that we documented in healthy volunteers were replicated in cancer patients.”
Up to 40 percent of people with cancer suffer from a mood disorder, according to the National Comprehensive Cancer Network.
Anticipating wide interest in the psilocybin research from scientists, clinicians and the public, the journal solicited 11 commentaries to be co-published with the study results written by luminaries in psychiatry, palliative care and drug regulation, including two past presidents of the American Psychiatric Association, a past president of the European College of Neuropsychopharmacology, the former deputy director of the U.S. Office of National Drug Control Policy, and the former head of the U.K. Medicines and Healthcare Products Regulatory Authority. In general, the commentaries were supportive of the research and of using these drugs in a clinical setting as tools for psychiatry.
Novel study identifies an area of the mosquito brain that mixes taste and smell
A new study by Johns Hopkins researchers suggests that a specialized area of the mosquito brain mixes tastes with smells to create unique and preferred flavors. The findings advance the possibility, they say, of identifying a substance that makes “human flavor” repulsive to the malaria-bearing species of the mosquitoes, so instead of feasting on us, they keep the disease to themselves, potentially saving an estimated 450,000 lives a year worldwide.
A report on the research appeared online on Oct. 3 in the journal Nature Communications. Malaria is an infectious parasite disease of humans and animals transmitted by the bite of the female Anopheles gambiaemosquito. In 2015, experts estimate it affected 214 million people, mostly in Africa, despite decades of mosquito eradication and control efforts. There is no malaria vaccine, and although the disease is curable in early stages, treatment is costly and difficult to deliver in places where it is endemic.
“All mosquitoes, including the one that transmits malaria, use their sense of smell to find a host for a blood meal. Our goal is to let the mosquitoes tell us what smells they find repulsive and use those to keep them from biting us,” says Christopher Potter, Ph.D., assistant professor of neuroscience at the Johns Hopkins University School of Medicine.
Because smell is essential to mosquito survival, each mosquito has three pairs of “noses” for sensing odors: two antennae, two maxillary palps and two labella. The maxillary palps are thick, fuzzy appendages that protrude from the lower region of the mosquito’s head, more or less parallel to its proboscis, the long, flexible sheath that keeps its “feeding needle” under wraps until needed. At the very tip of the proboscis are the labella, two small regions that contain both “gustatory” neurons that pick up tastes and olfactory neurons for recognizing odorants.
To better understand how An. gambiae mosquitoes that cause malaria receive and process olfactory information from so many sensory regions, Potter’s team wanted to see where olfactory neurons from those regions go to in the brain.
They used a powerful genetic technique — never before accomplished in mosquitoes, according to Potter — to make certain neurons “glow” green. The green glowing label was designed to appear specifically in neurons that receive complex odors through proteins called odorant receptors (ORs), since OR neurons are known to help distinguish humans from other warm-blooded animals in Aedes aegypti mosquitoes, which carry the Zika virus.
“This is the first time researchers managed to specifically target sensory neurons in mosquitoes. Previously, we had to use flies as a proxy for all insects, but now we can directly study the sense of smell in the insects that spread malaria,” says Olena Riabinina, Ph.D., the lead author of the study and a postdoctoral fellow now at the Imperial College London. “We were pleasantly surprised by how well our genetic technique worked and how easy it is now to see the smell-detecting neurons. The ease of identification will definitely simplify our task of studying these neurons in the future.”
As expected, Potter says, the OR neurons from the antennae and maxillary palps went to symmetrical areas of the brain called antennal lobes, just as they do in flies. But Potter was quite surprised when he saw that the OR neurons from the labella went to the so-called subesophageal zone, which, he says, had never before been associated with the sense of smell in any fly or insect; it had only been associated with the sense of taste.
“That finding suggests that perhaps mosquitoes don’t just like our smell, but also our flavor,” says Potter. “It’s likely that the odorants coming off our skin are picked up by the labella and influence the preferred taste of our skin, especially when the mosquito is looking for a place to bite.”
Potter says the finding potentially offers researchers one more way to repel mosquitoes. The antennae and maxillary palps are more specialized for picking up long-range signals, while the labella come into direct contact with our skin. In fact, Potter says, before injecting their needlelike proboscis, mosquitoes use the labella to probe about on a victim’s skin. “We don’t really know why they do that, but we suspect that they’re looking for sensory cues that hint at easy access to a blood vessel,” he says. “This suggests that a combination of repellants could keep mosquitoes from biting us in two ways. One could target the antennal neurons and reduce the likelihood that they come too close, while another could target the labellar neurons and make the mosquitoes turn away in disgust — before sucking our blood — if they got close enough to land on us.”
The two-part genetic system Potter devised to generate the glowing neurons will make it much easier for his and other laboratories to mix and match genetically altered mosquitoes to generate new traits, he says. His group has already created a strain of An. gambiaemosquitoes whose OR neurons glow green upon activation. Scientists can thus see which neurons light up in response to a specific smell.
“Using this method, we hope to find an odorant that is safe and pleasant-smelling for us but strongly repellant to mosquitoes at very low concentrations,” says Potter.
His group was also able to compare the brains of male and female mosquitoes. Since only females use their sense of smell to find humans and males feed only on nectar, it was previously thought that males had just a rudimentary sense of smell. The Potter group found instead that males have the same level of complexity in their brains to detect odors as females but have fewer olfactory neurons. “It appears that males might just have a scaled-down version of a female’s sense of smell. So they can still smell everything a female smells, just not as well,” Potter says.
His group plans to study other types of neurons to better understand how signals from the mosquitoes’ three types of olfactory receptors interact to influence their behavior. For example, why is lactic acid not attractive on its own but highly attractive when mixed with carbon dioxide?
“We’d like to figure out what regions and neurons in the brain lead to this combined effect,” says Potter. “If we can identify them, perhaps we could also stop them from working.”
Mini midbrains provide next generation platforms to investigate human brain biology, diseases and therapeutics
Scientists in Singapore have made a big leap on research on the ‘mini-brain’. These advanced mini versions of the human midbrain will help researchers develop treatments and conduct other studies into Parkinson’s Disease (PD) and ageing-related brain diseases.
These mini midbrain versions are three-dimensional miniature tissues that are grown in the laboratory and they have certain properties of specific parts of the human brains. This is the first time that the black pigment neuromelanin has been detected in an organoid model. The study also revealed functionally active dopaminergic neurons.
The human midbrain, which is the information superhighway, controls auditory, eye movements, vision and body movements. It contains special dopaminergic neurons that produce dopamine – which carries out significant roles in executive functions, motor control, motivation, reinforcement, and reward. High levels of dopamine elevate motor activity and impulsive behaviour, whereas low levels of dopamine lead to slowed reactions and disorders like PD, which is characterised by stiffness and difficulties in initiating movements.
The Johns Hopkins University School of Medicine (JHUSOM), located in Baltimore, Maryland, U.S., is the academic medical teaching and research arm of Johns Hopkins University.
Johns Hopkins has consistently been among the nation’s top medical schools in the number of research grants awarded by the National Institutes of Health. Its major teaching hospital, the Johns Hopkins Hospital, was ranked the best hospital in the United States every year between 1991 and 2011 and again in 2013 by U.S. News and World Report.
According to the Flexner Report, Hopkins has served as the model for American medical education. It was the first medical school to require its students to have an undergraduate degree and was also the first graduate-level medical school to admit women on an equal basis as men. Mary Elizabeth Garrett, head of the Women’s Medical School Fund, was a driving force behind both of these firsts. School founder Sir William Osler became the first Professor of Medicine at Johns Hopkins and the Physician-in-Chief at Johns Hopkins Hospital. Osler was responsible for establishing the residency system of postgraduate medical training, where young physicians were required to “reside” within the hospital to better care for their patients.
The Latest Updated Research News:
Johns Hopkins Medicine research articles from Innovation Toronto
- Sophisticated ‘Mini-Brains’ Add to Evidence of Zika’s Toll on Fetal Cortex – April 24, 2016
- Portion Control: Cells Found in Mouse Brain That Signal ‘Stop Eating’ – March 18, 2016
- Protein therapeutic reverses cirrhosis in lab rats – March 6, 2016
- Mind-Controlled Prosthetic Arm Moves Individual ‘Fingers’ – February 17, 2016
- Biodegradable implant could help heal broken bones – November 3, 2015
- Computer Algorithm Can Forecast Patients’ Deadly Sepsis – August 7, 2015
- New Experimental Test Detects Signs of Lyme Disease Near Time of Infection – February 17, 2016
- Noninvasive brain stimulator may ease Parkinson’s symptoms – June 21, 2015
- Vaccine ‘Reprograms’ Pancreatic Cancers to Respond to Immunotherapy – June 18, 2014
- Researchers Use Human Stem Cells to Create Light-Sensitive Retina in a Dish – June 16, 2014
- Recycling a Patient’s Lost Blood During Surgery Better Than Using Banked Blood | recycled blood – May 12, 2014
- Johns Hopkins Scientists Alter Fat Metabolism in Animals to Prevent Most Common Type of Heart Disease | D-PDMP
- New Guidance System Could Improve Minimally Invasive Surgery
- Experts issue ‘blueprint for action’ to combat shortages of life-saving drugs
- Lab-Grown, Virus-Free Stem Cells Repair Retinal Tissue in Mice
- A Simple Blood Test May Catch Early Pancreatic Cancer
- Researchers Step Closer to Custom-building New Blood Vessels
- Study Demonstrates That Once-a-Day Pill Offers Relief From Ragweed Allergy Symptoms
- Study Demonstrates That Once-a-Day Pill Offers Relief From Ragweed Allergy Symptoms
- Asthma Drug Found Highly Effective in Treating Chronic, Severe Hives and Itch
- Tissue Engineers Report Knee Cartilage Repair Success with New Biomaterial
- Experts aim to redefine healthcare and research ethics
- Hydrogen Peroxide Vapor Enhances Hospital Disinfection of Superbugs
- Johns Hopkins Surgeons Implant Brain “Pacemaker” for Alzheimer’s Disease in United States as Part of a Clinical Trial Designed to Slow Memory Loss
When it comes to early diagnosis of Lyme disease, the insidious tick-borne illness that afflicts about 300,000 Americans annually, finding the proverbial needle in the haystack might be a far easier challenge—until now, perhaps. An experimental method developed by federal and university researchers appears capable of detecting the stealthy culprit Lyme bacteria at the earliest time of infection, when currently available tests are often still negative.
The team suggests the approach might also be useful for early detection of other elusive bacterial infections. The collaborators—from the National Institute of Standards and Technology (NIST), Institute for Bioscience and Biotechnology Research, and Johns Hopkins School of Medicine—recently reported the successful first trial of their new method.
“Our hypothesis was that Lyme bacteria shed vesicle-like particles—or fragments—derived from the cell wall of the bacteria circulating in the serum of individuals. These particles would contain membrane proteins that can be detected to provide a unique indicator of infection,” explains NIST research chemist Larik Turko.
The challenge was to detect these bacterial membrane proteins among the far, far more plentiful proteins normally present in serum, the watery, cell-free component of blood. The researchers speculated that running serum samples through a high-speed centrifuge—a standard step in chemistry labs—might selectively concentrate the larger, heavier fragments containing the bacterial membrane proteins into pellets. In effect, they predicted, this step would separate the wheat—the sparse target proteins—from the chaff—the much more abundant human serum proteins.
The new method’s promise was demonstrated in tests on serum samples drawn from three patients with undetected Lyme disease at the time of their initial doctor visit. By customizing standard analytical techniques for determining the types and amounts of chemicals in a sample, the team detected extremely small amounts of the target protein in all three samples.
For chemistry buffs, the protein in enriched samples was present at a level of about four billionths of a millionth of a mole, the standard unit for amount of substance.
In one patient, the experimental method detected the bacteria three weeks before infection was confirmed with the standard blood tests now used. For the other two, infection was detected simultaneously by the two methods.
“The complexity of Lyme disease, combined with lack of biomarkers to measure infection, has slowed progress,” study collaborator John Aucott, head of the Johns Hopkins Lyme Disease Clinical Research Center, said in advance of a session on precision and personalized medicine this weekend at the AAAS 2016 Annual Meeting in Washington, D.C. “Now, thanks to recent advances in technology, the tiniest concentration of blood molecules can now be detected, molecules that were previously ‘invisible’ to scientists.”
The current standard blood test for Lyme disease exposes the infection only after antibodies have accumulated to detectable levels, which can take up to 4 to 6 weeks. If patients exhibit a telltale bull’s-eye rash, diagnosis and treatment can begin earlier. But the rash does not occur in 20 to 30 percent of Lyme disease patients, according to the Centers for Disease Control and Prevention.
Rather than waiting for an infected person’s immune system to produce noticeable amounts of antibodies, the team chose to home in on the bacteria itself—specifically, proteins the bug sheds when attacked by the body’s defenses.
“From many candidates, we chose one that is both easily distinguished from human serum proteins and an unambiguous indicator of the bacteria,” Turko says. “This protein, which resides on the outer surface of membranes, became the target of our search in serum samples.”
But finding that target required an important preliminary step to ensure the accuracy of their measurements: making a reference sample that contained ample amounts of the target protein. With the reference sample, the team established the unmistakable signature the bug’s outer-surface membrane protein would yield when they examined samples drawn from patients. As a result of these steps, the team could detect the copies of the target protein, even though human proteins were 10 million times more plentiful.
“We believe that this approach may be universally applicable to detection of other bacterial infections in humans,” the researchers write.