Role of microglia in neurodegeneration -effect of apoe

Active Project Grant Awarded Last action

Award ID
R01AG075840
Recipient
Awarding agency
Obligated
$7,380,718

Award facts

Assistance listing
93.866 Aging Research
Completion date 92% complete
Place of performance
New York, NY 10016, USA

Award details come from USAspending.gov.

Description

Abstract
Like alzheimer's disease, prion diseases (prionoses) are conformational disorders, in which deposition of misfolded proteins is accompanied by microglia neurodegenerative phenotype (mgnd) displaying mixed phagocytic and inflammatory properties. Prion mouse models with misfolded protein driven neurodegeneration and activated glia response can be used to uncover alzheimer's disease relevant pathomechanisms. Apoe E4 allele is the foremost risk factor in sporadic alzheimer's disease, increasing its odds by 3 and 15-fold in hetero and homozygotes, respectively. Apoe encodes apolipoprotein (APO) e, which controls brain lipid homeostasis and modulates alzheimer's disease risk through isoform-specific effect on clearance and deposition of soluble ASS. Apoe is expressed by astrocytes in form of apoe/hdls and also by mgnd as lipid-poor particles. Differential contributions of these two apoe pools to mgnd properties remain unclear. While lipidated apoe may facilitate clearance of misfolded proteins, expression of lipid-poor apoe by mgnd is linked to their pro-inflammatory properties, which also are differentially controlled by apoe genotype. In prionoses, accumulation of toxic prpsc protein is the culprit of pathogenesis. Microglia undergo activation early in the course of disease and exert opposing roles in prpsc mediated neurodegeneration. While clearance of prpsc has a disease-limiting effect, microglia-driven neuroinflammation is deleterious to neurons. Involvement of apoe in prion pathogenesis has not been established, though there is evidence for ~2-fold higher risk of sporadic creutzfeldt-jakob disease (CJD) in E4 carriers. Our preliminary work shows increased brain apoe level in prion infected mice along with reduced apoe expression in astrocytes and increased expression in activated microglia. The overall effect of apoe in prionoses is beneficial as global apoe KO exacerbates prion pathology by aggravating the vicious cycle of neuronal death and neuroinflammation. In apoe-/- mice, clearance of prpsc and dying neurons by mgnd becomes inefficient while neuronal debris exaggerate mgnd phenotype, release of inflammatory cytokines, and induce A1 neurotoxic astrocytes. Our studies also suggest, apoe effect in prionoses is isoform dependent. E4/E4 targeted replacement (TR) mice have shorter disease incubation time, increased pathology load and microglia hyperactivation compared to E3/E3 and E2/E2 mice. This preliminary work led US to hypothesize 1) apoe involvement in prion pathogenesis is by control of microglia response to prpsc mediated neurodegeneration; 2) apoe-based approaches have therapeutic merit in prionoses; and 3) effect of apoe in human prionoses is isoform dependent. These hypotheses shall be explored in grant's specific aims. Aim i will assess the role of astrocyte VS. Microglia-expressed apoe on prpsc mediated neurodegeneration in mice with cell-specific conditional apoe knock out. Aim II will assess whether regulating lipidation level of astrocytic and microglial apoe and the total brain apoe level modulates neurodegeneration. Aim III will explore effects of apoe genotype on microglia activation phenotype in prion infected apoe TR mice and in sporadic CJD and alzheimer's disease patients.

Transactions

Action Obligated Date
Amendment $680,533
Amendment $54,443
Amendment $612,480
Amendment $612,480
Amendment $68,053
Amendment $68,053
Amendment $68,053
Amendment $612,480
Amendment $612,480
Amendment $612,480
Amendment $612,480
Amendment $680,533
Amendment $680,533
Amendment $680,533
Original award $725,104
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Subawards

Subrecipient Amount Awarded
Indiana University Health Bedford, Inc. Role of Microglia in Neurodegeneration -Effect of ApoE $93,984
Indiana University Health Bedford, Inc. $93,984
Indiana University Health Bedford, Inc. $39,188
Indiana University Health Bedford, Inc. $87,083

Quick answers

Who received award R01AG075840?

R01AG075840 was awarded to New York University by National Institute on Aging (National Institutes of Health) on June 15, 2022.

How much is award R01AG075840 worth?

$7,380,718 has been obligated on R01AG075840.

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