Modulation of the endocytic, bioenergetic and transcriptomic pathways subserve the neuroprotective, anti-amyloidogenic action of cleavage-specific tau 12A12mAb in Alzheimer's Disease mouse model

Beyond deficits in hippocampal-dependent episodic memory, Alzheimer's Disease (AD) features sensory impairment in visual cognition consistent with extensive neuropathology in the retina. 12A12 is a monoclonal cleavage specific antibody (mAb) which in vivo selectively neutralizes the AD-relevant, harmful N-terminal 20-22kDa tau fragment(s) (i.e NH2htau) without altering the full-length normal protein. When systemically-injected into Tg2576 mouse model overexpressing a mutant form of Amyloid Precursor Protein (APP), APPK670/671L linked to early-onset familial AD, this conformation-specific tau mAb successfully neutralizes the NH2htau accumulating both in their brain and retina and, thus, markedly alleviates the phenotype-associated signs. By means of combined biochemical and metabolic and transcriptomic experimental approach, we report that 12A12mAb downregulates the steady state expression levels of APP and Beta-Secretase 1 (BACE-1) and, thus, limits the Amyloid beta (Aß) production both in hippocampus and retina from this AD animal model. The endocytic (BIN1, RIN3) and bioenergetic (glycolisis and mitochondria) pathways controlling the cellular fate of APP processing towards the amyloidogenic route subserve the local, antibody-mediated anti-amyloidogenic action in vivo. Our results show for the first time that similar molecular and metabolic retino-cerebral pathways are modulated in coordinated fashion in response to 12A12mAb treatment to tackle the neurosensorial Aß accumulation in AD neurodegeneration. Overall design: Comparative gene expression profiling analysis of RNA-seq data for hippocampi and retinas of wild-type, naive Tg-AD, Tg-AD+mAb mice.