Slices of living human brain, taken during neurosurgery and kept alive in the lab, released far less of the inflammatory messenger interleukin-1 beta once a drug blocked a receptor called P2X7. Professor Nicholas Barnes of the University of Birmingham, who led the work and is corresponding author on the paper in the journal Brain, calls P2X7 “a critical receptor that when blocked inhibits neuroinflammation.” The result is a step toward testing compounds that already exist, not a new drug.
P2X7 and the inflammation switch in microglia
P2X7 sits on the surface of microglia, the brain’s resident immune cells, and responds to signals that leak out of damaged or dying cells. When it is triggered, cells release the cytokines IL-1 beta and IL-18, a response tied to the NLRP3 inflammasome, a protein complex that works through the enzyme caspase-1. In the experiments, the P2X7 activator BzATP, a compound used to stimulate the receptor on purpose, produced a concentration-dependent release of both cytokines from brain slices and from lab-built microglia.
The Brain paper, “P2X7 receptor-mediated IL-1β release by human brain tissue: the impact of CNS-penetrant potential therapeutics,” has 37 authors from Birmingham and partner institutions. Its abstract page lists the tissue sources: precision-cut slices of adult cortical or cerebellar tissue removed during neurosurgery, and microglia-like cells converted from blood monocytes of healthy donors. The authors explain that native microglia lose their defining traits once taken out of the brain, which is why the blood-derived cells serve as a scalable stand-in.
The inflammatory drop in human brain slices
Selective P2X7 antagonists reduced the cytokine release. In brain slices the effect appeared at pharmacologically relevant concentrations, meaning levels a drug could plausibly reach in a patient. Inhibitors of NLRP3 (MCC950) and caspase-1 (VX-765) also cut the response, which points to the inflammasome as the route from receptor to cytokine. In the blood-derived microglia, one compound, JNJ-54175446, was the most potent at blocking IL-1 beta release, ahead of JNJ-55308942 and A-804598.
The University of Birmingham’s announcement of the study says blocking the receptor “significantly” reduced the inflammatory response in human brain tissue, and that the antagonist also interfered with damage signals released by microglia as they were injured and died. The abstract page indicates experiments were repeated across at least five independent donors or tissue samples, while the full donor demographics sit in a supplementary table.
Existing drugs and the road to patients
Barnes described the discovery as “a major step toward repurposing existing therapeutics to combat neuroinflammation at its source.” The qualifier matters. The two JNJ compounds are described in the paper as clinical-stage, brain-penetrant antagonists, meaning they were developed to reach the brain and advance toward human testing, while A-804598 is a research tool. None is described as an approved treatment for any brain disorder, and the release itself does not name the compound it refers to. That gap between the release and the paper is worth keeping in view: “existing drugs” here means candidates that have been built and characterized, several with the specific property of entering the brain, and the paper’s title itself calls them “CNS-penetrant potential therapeutics,” a phrase that stops short of calling them treatments. Any move into patients would have to show benefit, and not only a lower cytokine reading in a dish.
That pedigree is the point of the work. A brain-penetrant P2X7 blocker with human safety data could skip years of early development if it proves useful. Barnes and Antonio Belli, Birmingham’s professor of trauma neurosurgery, began the line of research in a Medical Research Council-funded project announced in March 2021, which set out to test whether P2X7 blockers could limit the secondary damage that follows traumatic brain injury. That university announcement notes there were “no approved drugs available in the clinic” for it.
Brain injury shows the appeal. After a head injury the first wave of damage is followed, over hours to days, by a second wave in which dying tissue triggers inflammation that spreads into neighboring tissue and enlarges the injured area. Barnes’s 2021 project framed P2X7 as one of the regulators of that spread, linked to brain cell death and to the release of pro-inflammatory chemicals.
The university names traumatic brain injury, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, depression and psychosis as conditions where neuroinflammation matters and where the approach could apply. This study tested none of them in patients. News-Medical’s report on the release notes the work is laboratory-based, using cell cultures and tissue slices, with no clinical efficacy reported.
Barnes said “the next stage for this research is the development of clinical trials in patients with neurodegenerative conditions and patients with TBI.” No trial dates have been given, and a ScienceDaily summary from Oct. 7 repeats the same plan.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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