B cells are thought to play a critical role in innate and adaptive immunity, but their exact role in anti-tumour immunity remains unknown. Looking at B cells with a technique called single-cell profiling, which looks at all the genes in the cell, researchers found a protein that – when deleted – reduced tumour growth. The researchers write in Nature that this regulator could be a target for new cancer treatments.
The team, consisting of immunologists at Brigham and Women’s Hospital and dermatologists from Massachusetts General Hospital, identified a subset of B cells that expands specifically in the draining lymph node over time in mice with melanoma tumours.
They found a cell surface receptor called TIM-1 expressed on these B cells during melanoma growth. They also characterised multiple accompanying cell surface proteins that were involved in the B cell’s immune function. Interestingly, they found that deleting a molecule TIM-1, but not any of the other accompanying proteins, dramatically decreased tumour growth. The researchers concluded that TIM-1 controls B cell activation and immune response that combats cancer, including activating another type of the killer tumour-specific T cells for inhibiting tumour growth.
“The collaboration across institutions was extremely fruitful as we combined our immunology expertise at the Brigham with work at David Fisher’s MGH laboratory where seminal discoveries in skin malignancies have been made,” said lead author Lloyd Bod, PhD, of the Department of Neurology at the Brigham, who conducted this work while completing his postdoctoral fellowship at the Brigham. “The collaboration allowed us to test and demonstrate the therapeutic potential of targeting TIM-1 in melanoma models.”
New research published in Nature Communications has found that in a mouse model mimicking Alzheimer’s Disease (AD) pain signals are not processed in the same way as in healthy mice. The research, from King’s College London, suggests that the perception of pain in people with Alzheimer’s Disease may be altered, and asks whether changes in management of pain in people with AD could improve their quality of life.
While chronic musculoskeletal pain is common in individuals with AD, it remains largely untreated as it can go unreported due to the cognitive deficits attached to the disease.
In this study, the researchers sought to explore whether there is also an alteration in the body’s response to pain by the nervous system in people with AD.
In healthy mice, pain signals are transmitted from the point of origin to the central nervous system to initiate an immune response. The protein Galectin-3 has been demonstrated to be responsible for pain signal transmission to the spinal cord. Upon reaching the spinal cord, it binds to another protein, TLR4, to initiate the immune response.
In this study, researchers used an AD mice model and gave them rheumatoid arthritis, a type of chronic inflammatory disease, through blood transfer. They observed an increase in allodynia, pain caused by a stimulus that doesn’t normally provoke pain, as a response to the inflammation. They also saw increased activation of a microglia in the spinal cord. They determined that these effects were regulated by TLR4.
Researchers found that the mice with AD lacked TLR4 in the immune cells of their central nervous system and were therefore unable to respond to pain in the typical way as the signals were not being perceived.
This resulted in the mice with AD developing less joint inflammation related pain, and a less powerful immune cell response to the pain signals received by the central nervous system.
Professor Marzia Malcangio, Professor of Neuropharmacology at King’s IoPPN and the study’s senior author said, “Nociceptive pain – pain which is the result of tissue damage – is the second most prevalent comorbidity in individuals with Alzheimer’s disease. Our study has shown that, in mice with Alzheimer’s, the body’s ability to process that pain is altered due to the lack of TLR4; a protein vital to the immune response process in the central nervous system.
“These are important findings, as untreated pain can contribute to the psychiatric symptoms of the disease. Increasing our understanding of this area could, with more research, lead to more effective treatments and ultimately improve people’s quality of life.”
George Sideris-Lampretsas, a PhD student at King’s IoPPN and the study’s first author said, “The results of this study have the potential to make an impact, not only by identifying Galectin-3/TLR4 as a potential therapeutic target for chronic pain, but most importantly by raising awareness around the underreported and untreated pain experienced by patients with AD.”
In spite of burgeoning studies, the biological roots of autism remain elusive. Microbial approaches however have shown some promise, and now a study published in Nature Neuroscience has uncovered a microbial signature associated with autism, which clearly overlaps with metabolic pathways.
The study re-analysed of dozens of previously published datasets and found that they align with a recent, long-term study of autistic individuals that used a microbiome-focused intervention. These findings also underscore the importance of longitudinal studies in elucidating the interplay between the microbiome and complex conditions such as autism.
“We were able to harmonise seemingly disparate data from different studies and find a common language with which to unite them. With this, we were able to identify a microbial signature that distinguishes autistic from neurotypical individuals across many studies,” says Jamie Morton, one of the study’s corresponding authors. “But the bigger point is that going forward, we need robust long-term studies that look at as many datasets as possible and understand how they change when there is a [therapeutic] intervention.”
With 43 authors, this study brought together leaders in computational biology, engineering, medicine, autism and the microbiome who hailed from institutions in North America, South America, Europe and Asia. “The sheer number of fields and areas of expertise in this large-scale collaboration is noteworthy and necessary to get a new and consistent picture of autism,” says Rob Knight, the director of the Center for Microbiome Innovation at the University of California San Diego and a study co-author.
Autism is inherently complex, and studies that attempt to pinpoint specific gut microbes involved in the condition have been confounded by this complexity. First, autism presents in heterogeneous ways – autistic individuals differ from each other genetically, physiologically and behaviourally. Second, the microbiome presents unique difficulties. Microbiome studies typically report simply the relative proportions of specific microbes, requiring sophisticated statistics to understand which microbial population changes are relevant to a condition of interest.
This makes it challenging to find the signal amongst the noise. Making matters more complicated, most studies to date have been one-time snapshots of the microbial populations present in autistic individuals. “A single time point is only so powerful; it could be very different tomorrow or next week,” says study co-author Brittany Needham, assistant professor of anatomy, cell biology and physiology at the Indiana University School of Medicine.
“We wanted to address the constantly evolving question of how the microbiome is associated with autism, and thought, ‘let’s go back to existing datasets and see how much information we may be able to get out of them,'” says co-corresponding author Gaspar Taroncher-Oldenburg, director of Therapeutics Alliances at New York University, who initiated the work with Morton while he was a consultant-in-residence for SFARI.
In the new study, the research team developed an algorithm to re-analyse 25 previously published datasets containing microbiome and other “omic” information, such as gene expression, immune system response and diet, from both autistic and neurotypical cohorts. Within each dataset, the algorithm found the best matched pairs of autistic and neurotypical individuals in terms of age and sex, two factors that can typically confound autism studies.
Novel computational methodologies
“Rather than comparing average cohort results within studies, we treated each pair as a single data point, and thus were able to simultaneously analyse over 600 ASD-control pairs corresponding to a de facto cohort of over 1200 children,” says Taroncher-Oldenburg. “From a technical standpoint, this required the development of novel computational methodologies altogether,” he adds. Their new computational approach enabled them to reliably identify microbes that have differing abundances between ASD and neurotypical individuals.
The analysis identified autism-specific metabolic pathways associated with particular human gut microbes. Importantly, these pathways were also seen elsewhere in autistic individuals, from their brain-associated gene expression profiles to their diets. “We hadn’t seen this kind of clear overlap between gut microbial and human metabolic pathways in autism before,” says Morton.
Even more striking was an overlap between microbes associated with autism, and those identified in a recent long-term faecal microbiota transplant study led by James Adams and Rosa Krajmalnik-Brown at Arizona State University. “Another set of eyes looked at this, from a different lens, and they validated our findings,” says Krajmalnik-Brown, who was not involved in this study.
“What’s significant about this work is not only the identification of major signatures, but also the computational analysis that identified the need for future studies to include longitudinal, carefully designed measurements and controls to enable robust interpretation,” says Kelsey Martin, executive vice president of SFARI and the Simons Foundation Neuroscience Collaborations, who was not involved in the study.
“Going forward, we need more long-term studies that involve interventions, so we can get at cause-and-effect,” says Morton. Taroncher-Oldenburg, who cites the compliance issues often faced by traditional long-term studies, suggests that study designs could more effectively take into account the realities of long-term microbiome sampling of autistic individuals. “Practical, clinical restrictions must inform the statistics, and that will inform the study design,” he says. Further, he points out that long-term studies can reveal insights about both the group and the individual, as well as how that individual responds to specific interventions over time.
Importantly, researchers say these findings go beyond autism. The approach set forth here could also be employed across other areas of biomedicine that have long proved challenging. “Before this, we had smoke indicating the microbiome was involved in autism, and now we have fire. We can apply this approach to many other areas, from depression to Parkinson’s to cancer, where we think the microbiome plays a role, but where we don’t yet know exactly what the role is,” says Knight.
In a new study, scientists at Stanford Medicine have described a new category of depression, the cognitive biotype, which accounts for 27% of depressed patients and is not effectively treated by commonly prescribed antidepressants. The findings were reported in JAMA Network.
For these patients, cognitive tasks showed difficulty in planning ahead, self-control, sustaining focus despite distractions and suppressing inappropriate behaviour; imaging showed decreased activity in two brain regions responsible for those tasks.
Because depression has traditionally been defined as a mood disorder, doctors commonly prescribe selective serotonin reuptake inhibitors (SSRIs), but these are less effective for patients with cognitive dysfunction. Researchers said that targeting these cognitive dysfunctions with less commonly used antidepressants or other treatments may alleviate symptoms and help restore social and occupational abilities.
The study is part of a broader effort by neuroscientists to find treatments that target depression biotypes, according to the study’s senior author, Leanne Williams, PhD, professor of psychiatry and behavioural sciences.
“One of the big challenges is to find a new way to address what is currently a trial-and-error process so that more people can get better sooner,” Williams said. “Bringing in these objective cognitive measures like imaging will make sure we’re not using the same treatment on every patient.”
Finding the biotype
In the study, 1008 adults with previously unmedicated major depressive disorder were randomly given one of three widely prescribed typical antidepressants: escitalopram (Lexapro) or sertraline (Zoloft), which act on serotonin, or venlafaxine-XR (Effexor), which acts on both serotonin and norepinephrine. Seven hundred and twelve of the participants completed the eight-week regimen.
Before and after treatment with the antidepressants, the participants’ depressive symptoms were measured using two surveys – one, clinician-administered, and the other, a self-assessment, which included questions related to changes in sleep and eating. Measures on social and occupational functioning, as well as quality of life, were tracked as well.
The participants also completed a series of cognitive tests, before and after treatment, measuring verbal memory, working memory, decision speed and sustained attention, among other tasks.
Before treatment, scientists scanned 96 of the participants using functional magnetic resonance imaging as they engaged in a task called the “GoNoGo” that requires participants to press a button as quickly as possible when they see “Go” in green and to not press when they see “NoGo” in red. The fMRI tracked neuronal activity by measuring changes in blood oxygen levels, which showed levels of activity in different brain regions corresponding to Go or NoGo responses. Researchers then compared the participants’ images with those of individuals without depression.
The researchers found that 27% of the participants had more prominent symptoms of cognitive slowing and insomnia, impaired cognitive function on behavioural tests, as well as reduced activity in certain frontal brain regions – a profile they labelled the ‘cognitive biotype’.
“This study is crucial because psychiatrists have few measurement tools for depression to help make treatment decisions,” said Laura Hack, MD, PhD, the lead author of the study and an assistant professor of psychiatry and behavioural sciences. “It’s mostly making observations and self-report measures. Imaging while performing cognitive tasks is rather novel in depression treatment studies.”
Pre-treatment fMRI showed those with the cognitive biotype had significantly reduced activity in the dorsolateral prefrontal cortex and dorsal anterior cingulate regions during the GoNoGo task compared with the activity levels in participants who did not have the cognitive biotype. Together, the two regions form the cognitive control circuit, which is responsible for limiting unwanted or irrelevant thoughts and responses and improving goal selection, among other tasks.
After treatment, the researchers found that for the three antidepressants administered, the overall remission rates were 38.8% for participants with the newly discovered biotype and 47.7% for those without it. This difference was most prominent for sertraline, for which the remission rates were 35.9% and 50% for those with the biotype and those without, respectively.
“Depression presents in different ways in different people, but finding commonalities – like similar profiles of brain function – helps medical professionals effectively treat participants by individualising care,” Williams said.
Depression isn’t one size fits all
Williams and Hack propose that behaviour measurement and imaging could help diagnose depression biotypes and lead to better treatment. A patient could complete a survey on their own computer or in the doctor’s office, and if they are found to display a certain biotype, they might be referred to imaging for confirmation before undergoing treatment.
Researchers under Williams and Hack are studying another drug, guanfacine, that specifically targets the dorsolateral prefrontal cortex region. They believe this treatment could be more effective for patients with the cognitive subtype.
Williams and Hack hope to conduct studies with participants who have the cognitive biotype, comparing different types of medication with treatments such as transcranial magnetic stimulation (TMS) and cognitive behavioural therapy.
“I regularly witness the suffering, the loss of hope and the increase in suicidality that occurs when people are going through our trial-and-error process,” Hack said. “And it’s because we start with medications that have the same mechanism of action for everyone with depression, even though depression is quite heterogeneous. I think this study could help change that.”
As reported in the journal Science Advances, researchers at Baylor College of Medicine have come across a drug that, in laboratory cultures and animal models, significantly slows the development of antibiotic resistance in bacteira. The drug, called dequalinium chloride (DEQ), is a proof-of-concept for evolution-slowing drugs.
In this study, corresponding author Dr Susan M. Rosenberg and her colleagues looked for drugs that could prevent or slow down E. coli bacteria from developing resistance to two antibiotics when exposed to a third antibiotic, ciprofloxacin (cipro), the second most prescribed antibiotic in the US and one associated with high bacterial resistance rates.
The resistance is caused by new gene mutations that occur in the bacteria during infection. The drug DEQ reduces the speed at which new mutations are formed in bacteria, the team finds.
Previous work from the Rosenberg lab had shown that bacterial cultures in the lab exposed to cipro turn up mutation rate. They found a mutational “program” that is switched on by bacterial stress responses. Stress responses are genetic programs that instruct cells to increase production of protective molecules during stress, including stress from low concentrations of cipro. Low concentrations occur at the beginning and end of antibiotic therapies and if doses are missed.
The same stress responses also increase the ability to make genetic mutations, the Rosenberg group, then many other labs, have shown. Some of the mutations can confer resistance to cipro, while other mutations can allow resistance to antibiotics not yet encountered. Mutation-generating processes that are turned on by stress responses are called stress-induced mutation mechanisms.
Bacteria with antibiotic resistance mutations can then sustain an infection in the presence of cipro. This study is the first to show that in animal infections treated with cipro, the bacteria activate a known stress-induced genetic mutational process. Cipro resistance occurs mostly by the bacteria developing new mutations, both clinically and in the laboratory, rather than by acquiring genes that confer antibiotic resistance from other bacteria.
Looking to prevent the development of antibiotic resistance, the researchers screened 1120 drugs approved for human use for their ability to dial down the master bacterial stress response, which they showed counters the emergence of resistance mutations. In addition, and counterintuitively, they wanted “stealth” drugs that would not slow bacterial proliferation, which would confer a growth advantage to any bacterial mutants that resist the mutation-slowing drug itself. That is, drugs that are not antibiotics themselves.
“We found that DEQ fulfilled both requirements. Given together with cipro, DEQ reduced the development of mutations that confer antibiotic resistance, both in laboratory cultures and in animal models of infection, and bacteria did not develop resistance to DEQ,” said first author Yin Zhai, a postdoctoral associate in the Rosenberg lab. “In addition, we achieved this mutation-slowing effect at low DEQ concentrations, which is promising for patients. Future clinical trials are needed to evaluate the ability of DEQ to decelerate bacterial antibiotic resistance in patients.”
