A protein long implicated in diabetes and obesity may hold the key to treating Alzheimer’s disease by reinvigorating the brain’s immune system. New research suggests that blocking this protein, known as PTP1B, allows immune cells to clear toxic waste more effectively and restores cognitive function in mice. The findings were published in the Proceedings of the National Academy of Sciences. Alzheimer’s disease is characterized by the accumulation of sticky protein clumps called amyloid-beta. These plaques disrupt communication between brain cells and are widely believed to drive memory loss and neurodegeneration. The brain relies on specialized immune cells called microglia to maintain a healthy environment. In a healthy brain, microglia locate and engulf toxic clumps like amyloid-beta through a process called phagocytosis. However, in patients with Alzheimer’s, these immune cells often become lethargic. They fail to keep up with the accumulating waste, allowing plaques to spread. Scientists have struggled to find ways to safely reactivate these cells without causing damaging inflammation. There is a growing body of evidence linking Alzheimer’s to metabolic disorders. Conditions like type …