Neuronal deficiency of p38α-MAPK ameliorates symptoms and pathology of APP or Tau-transgenic Alzheimer's mouse models.

Alzheimer's disease (AD) is the leading cause of dementia with very limited therapeutic options. Amyloid beta (A beta) and phosphorylated Tau (p-Tau) are key pathogenic molecules in AD. P38 alpha-MAPK is specifically activated in AD lesion sites. However, its effects on AD pathogenesis, especially on p-Tau-associated brain pathology, and the underlying molecular mechanisms remain unclear. We mated human APP-transgenic mice and human P301S Tau-transgenic mice with mapk14-floxed and neuron-specific Cre-knock-in mice. We observed that deletion of p38 alpha-MAPK specifically in neurons improves the cognitive function of both 9-month-old APP and Tau-transgenic AD mice, which is associated with decreased A beta and p-Tau load in the brain. We further used next-generation sequencing to analyze the gene transcription in brains of p38 alpha-MAPK deficient and wild-type APP-transgenic mice, which indicated that deletion of p38 alpha-MAPK regulates the transcription of calcium homeostasis-related genes, especially downregulates the expression of grin2a, a gene encoding NMDAR subunit NR2A. Cell culture experiments further verified that deletion of p38 alpha-MAPK inhibits NMDA-triggered calcium influx and neuronal apoptosis. Our systemic studies of AD pathogenic mechanisms using both APP- and Tau-transgenic mice suggested that deletion of neuronal p38 alpha-MAPK attenuates AD-associated brain pathology and protects neurons in AD pathogenesis. This study supports p38 alpha-MAPK as a novel target for AD therapy.