Targeting IDOL-ApoE receptor pathway in Alzheimer's disease

点击翻译按钮获取中文摘要

Apolipoprotein E (APOE) genotype has long been known to strongly influence the risk and the onset of Alzheimer’s disease(AD), yet the exact mechanisms underlying remain incompletely defined. Accumulating evidence suggested that the functional combination of ApoE and its receptors act together to modify the risk for AD, and targeting brain ApoE receptors has recently emerged as a promising therapeutic strategy to combat AD. However, the lack of knowledge on the endogenous pathways regulating brain ApoE receptors is a major hurdle to advance ApoE receptors as accessible therapeutic targets in AD. Previously, we have identified the inducible degrader of the LDLR (IDOL), an E3 ubiquitin ligase, is a major post-translational regulator of three brain ApoE receptors: low-density lipoprotein receptor (LDLR), very low-density lipoprotein receptor (VLDLR), and ApoE Receptor 2 (ApoER2). Each of these three ApoE receptor plays key role in modulating ApoE actions and impacting AD pathogenesis. Our studies showed the genetic deletion or pharmacological inhibition of IDOL in the brain significantly increase the protein levels of ApoE receptors, ameliorate amyloid-β (Aβ) pathology, and improve cognitive functions in an AD mouse model, suggesting inhibition of brain IDOL activity may serve as a promising therapeutic strategy for AD. For the mechanistic and therapeutic implications, we propose to further investigate the multifactorial role and molecular mechanisms of IDOL-ApoE receptors pathway in modulating ApoE actions and impacting AD pathology. Aim 1 is to characterize the microglia-intrinsic role of IDOL in Aβ pathology. Aim 2 is to elucidate the mechanisms on how IDOL reduction facilitates microglia response to Aβ pathology. Aim 3 is to define the role of neuronal IDOL-ApoER2 pathway in protecting against ApoE4-induced synaptic dysfunction and cognitive deficit in AD.