In an extraordinary revelation, researchers at the University of Utah Health have uncovered a mechanism by which cancer can inadvertently provoke the body’s immune system to attack the brain, leading to rapid cognitive decline and neurological symptoms. This phenomenon, known as anti-Ma2 paraneoplastic neurological syndrome, represents a rare yet devastating complication of cancer, affecting fewer than one in 10,000 cancer patients. The syndrome is characterized by sudden memory loss, behavioral changes, loss of coordination, and seizures, symptoms that can severely impair a patient’s quality of life.
The groundbreaking study, led by Jason Shepherd, Ph.D., an associate professor of neurobiology at the University of Utah Health, alongside a multidisciplinary team, has identified a novel trigger for this immune system malfunction. The research reveals that certain tumors can express a protein that resembles a virus, sparking an aggressive immune response that mistakenly targets brain cells. This discovery opens new avenues for understanding and potentially treating a range of cancer-related neurological syndromes.
The Discovery of a Virus Lookalike
At the heart of this research is the PNMA2 protein, a component typically confined to the neurons in the brain. The study’s lead author, Junjie Xu, a graduate researcher in neurobiology, used advanced microscopy to reveal that PNMA2 can form 12-sided complexes similar to the geometric shapes of viral protein shells. This resemblance to viruses is crucial, as the immune system is programmed to attack viral invaders, inadvertently targeting PNMA2 when it adopts this virus-like configuration.
The implications of this discovery are profound. The immune system’s response to PNMA2, when it forms these virus-like complexes, suggests a fundamental misrecognition by the body’s defenses, treating these proteins as threats when they are expressed outside the brain. This misidentification leads to the production of antibodies against PNMA2, which, in turn, attack the brain itself.
Microscope image of PNMA2 proteins. Each starlike particle is a separate 12-sided complex.
The Role of Cancer in Triggering Immune Responses
The study highlights a critical link between cancer and the onset of neurological symptoms. According to Stacey L. Clardy, M.D., Ph.D., a neurologist at the University of Utah Health and coauthor of the study, patients often experience these symptoms before being aware of their cancer diagnosis. This suggests that the expression of PNMA2 by cancer cells can initiate an immune response before the cancer is even detected.
The research also sheds light on the vulnerability of the brain to immune attacks in the context of cancer. Normally protected from the immune system, the brain can become exposed when cancer weakens this natural barrier, making it susceptible to damage from the immune response triggered by PNMA2 outside the brain.
CAPTION – The three-dimensional structure of a PNMA2 complex, which can trigger a dangerous immune reaction when released by tumor cells. – CREDIT : Junjie Xu
Future Directions and Hope for Patients
The University of Utah Health team’s findings represent a significant step forward in understanding the complex interactions between cancer, the immune system, and neurological health. The identification of PNMA2’s role in triggering immune responses offers a potential target for future therapies aimed at preventing or mitigating the neurological effects of cancer.
As the research community continues to explore the mechanisms underlying these immune responses, there is hope for developing treatments that can block or neutralize the antibodies responsible for neurological symptoms. Such therapies could vastly improve the lives of patients affected by anti-Ma2 paraneoplastic neurological syndrome and similar conditions, offering relief from the debilitating symptoms that accompany these immune system malfunctions.
This innovative research underscores the importance of transdisciplinary collaboration in advancing our understanding of cancer’s impact on the body. By bridging the gap between neurobiology, immunology, and oncology, scientists at the University of Utah Health are paving the way for new therapeutic strategies that address the complex needs of cancer patients, particularly those suffering from neurological complications.
reference link :https://www.cell.com/cell/fulltext/S0092-8674(24)00011-4