Key Dates

Related Announcements

• December 30, 2024 - Research on Current Topics in Alzheimer's Disease and Its Related Dementias (R21 Clinical Trial Not Allowed). See NOFO PAR-25-331.
• December 30, 2024 - Research on Current Topics in Alzheimer's Disease and Its Related Dementias (R01 Clinical Trial Optional). See NOFO PAR-25-332.
• December 29, 2021 - Notice of Special Interest (NOSI): Genetic Underpinnings of Endosomal Trafficking as a Pathological Hub in Alzheimer's Disease and Alzheimer's Disease-Related Dementias (AD/ADRD). See Notice NOT-AG-21-034.

Issued by

National Institute on Aging (NIA)

Purpose

Background

Alzheimer's disease (AD) is defined, in part, by the appearance of extracellular amyloid deposits. Supported by genetic studies, the amyloid cascade is a leading hypothesis for the cause and pathogenesis of AD. Despite the intensive efforts that have been made in understanding amyloid and other pathological processes in AD, current approved interventions for AD have shown only modest effects in modifying clinical symptoms; none have been efficacious for slowing disease progression as demonstrated through clinical outcome measures.

Recent developments in the field of genetics have significantly advanced understanding of the etiology of AD. More than two dozen genes are now known to be associated with late-onset AD (LOAD). Using a combination of genome-wide association studies (GWAS), exome chips, imputation, whole exome sequencing (WES), and whole genome sequencing (WGS), a number of AD genetic “hubs” have recently begun to emerge that may explain some of the bases for the development of the disease. These hubs include the well-known amyloid precursor processing (APP) pathway and the less understood genetic and genomic events associated with cholesterol metabolism, neuroinflammation and cellular immunity, and endocytosis pathways. Known genes that appear to be directly or indirectly associated with the endosomal compartment include APOEe4, SORL1, BIN1, ABCA7, EPHA1, and CD2AP. Some genes are observed in more than one pathway, leaving open the possibility that individuals with multiply affected pathways may be more vulnerable to the pathophysiology associated with AD.

A newly emerging model proposes that alterations in the way the cellular endosomal compartment processes amyloid precursor protein (APP) may represent a pathogenic hub for AD. This model suggests that therapies directed against extracellular amyloid plaques may fail because they are being administered too late in the disease process. Many AD genes directly or indirectly converge upon the endosomal genetic hub. Thus, the hub may act as a common pathway through which many downstream pathophysiological effects can be mediated. In-depth assessment of the genetic components related to the endosomal cellular trafficking pathway may help direct the research community toward novel alternative biological targets for therapeutic interventions.

Research Objectives

The goal of this Notice of Special Interest (NOSI) is to encourage basic and translational research focused on the molecular, cellular, physiological, and pathological processes associated with the endosomal compartment in AD and AD-related dementias (ADRD). Studies funded under this topic will support research into AD/ADRD pathogenesis related to enhancing our understanding of how the genetic underpinnings of endosomal trafficking in AD/ADRD may act as a hub in the pathophysiological changes associated with the disease. The impact of changes in endosomal genetics on functional events, for example upon the generation of amyloid Beta (Aß) cellular processing, are important factors to be evaluated. This includes both the amyloidogenic and non-amyloidogenic pathways. All phases of endosomal processing during early through late processing stages are of interest, including those genes/events that may affect the cell membrane; early, mature, and late endosomes; the retromer/recycling pathway; the retrograde pathway/trans-Golgi network; the lysosome, endolysosome, and multi-vesicular body; receptors related to cellular trafficking and cell sorting; and other related cell processing components. Applications that delineate cellular gene ontology networks and determine the weight of their impact upon endosomal processing are of interest. Applications that apply Artificial Intelligence/Machine Learning methods to data analysis approaches in this area are welcome. 

Areas of research interest and opportunity that would be considered high priority under this topic include, but are not limited to, the following:

• Improved characterization (in vivo/in vitro) of the functions of known endosomal genes and their impact upon AD/ADRD pathophysiology.
• Identification and characterization of novel genes not presently known to be associated with the endosomal compartment.
• Analysis of existing whole genome and whole exome sequence data, such as that generated by the Alzheimer's Disease Sequencing Project (ADSP) to identify genetic variants and their function in known and novel endosomal genes.
• Determination of the impact of changes in endosomal genetics on functional events (amyloidogenic and non-amyloidogenic) in cellular trafficking in AD/ADRD.
• Definition and characterization of the relationship between genes associated with AD/ADRD and endosomal processing in specific neural cell populations; this includes neurons (i.e., soma, axonal, and/or dendritic) and glia.
• Characterization of cell types affected by changes in endosomal processing by physiological measures such as changes in neural activity.
• Identification and characterization of the impact of genes and networks of genes that are outside of the endosomal pathway to determine their links to endosomal trafficking in AD/ADRD.
• Delineation of cellular gene ontology networks related to endosomal processing and determination of the weight of their impact upon endosomal processing and pathophysiology.
• Identification of cellular networks and brain regions that are selectively vulnerable to changes in endosomal processing in AD/ADRD.
• Improvement of our understanding of how clusters of genes in the endosomal pathway may change endosomal trafficking resulting in pathological events in AD/ADRD; this includes a better understanding of how genes that act in more than one pathway impact endosomal processing, and a better understanding of converging and cascading pathways related to the endosomal compartment and how they may impact AD/ADRD pathophysiology.
• Analysis of in vivo and in vitro outcomes of interventions that are directly designed to increase traffic flow through the endosomal compartment and may serve as indicators of therapeutic approaches in AD/ADRD.
• Identification of novel therapeutic targets for AD/ADRD associated with the endosomal compartment using existing and new in vivo and/or in vitro approaches
• Development of strategies to modulate expression or function of potential therapeutic targets associated with the endosomal compartment in AD/ADRD.
• Development of endosomal compartment targeting strategies in specific brain cell types to restore endosomal trafficking homeostasis in AD/ADRD.
• Improvement of our understanding of how known and newly identified protective variants associated with the endosomal compartment may be leveraged into therapeutic targets for AD/ADRD.
• Determination of whether the amyloid hypothesis, when seen through the lens of genetic changes in endosomal processing, can aid in the identification of useful therapeutic targets that can be applied at the earliest possible stage in the disease process.
• Determination of whether/how the endosomal compartment may act as a common pathway through which downstream pathophysiological events in AD/ADRD can be mediated.
• Comprehensive analysis of how single-cell transcriptomic (e.g., RNAseq), epigenetic (e.g., chromatin remodeling, DNA methylation), and/or genomic (e.g., sequencing for mutations) events impact neurons and glial cells and are related to changes in the endosomal compartment.
• Novel multidisciplinary technological approaches to assess changes in the endosomal compartment in AD/ADRD.
• Analysis of trans-synaptic spread (e.g., by exosomes) in AD/ADRD that may be mediated by genetically modulated changes in endosomal trafficking.
• Research into endosomal trafficking genes and pathways that are shared or unique to difference stages of AD/ADRD progression and severity.
• Research into endosomal trafficking genes and pathways and their interactions with AD susceptibility or resilience genes/loci under various APOE backgrounds.
• Research on endosomal trafficking genes and molecular mechanisms shared or unique to AD, frontotemporal lobar degeneration (FTLD), Lewy body diseases (LBD), limbic-predominant age-related TDP-43 encephalopathy (LATE), and other related dementias.

Applications proposing clinical trials on this topic would not be considered a high priority.

Application and Submission Information

This notice applies to due dates on or after March 11, 2025 and subsequent receipt dates through November 17, 2027. 

Submit applications for this initiative using one of the following notices of funding opportunities (NOFOs) or any reissues of these announcements through the expiration date of this notice.

• PAR-25-331 - Research on Current Topics in Alzheimer's Disease and Its Related Dementias (R21 Clinical Trial Not Allowed)
• PAR-25-332 - Research on Current Topics in Alzheimer's Disease and Its Related Dementias (R01 Clinical Trial Optional)

All instructions in the How to Apply - Application Guide and the notice of funding opportunity used for submission must be followed, with the following additions:

• For funding consideration, applicants must include “NOT-AG-24-029” (without quotation marks) in the Agency Routing Identifier field (box 4B) of the SF424 R&R form. Applications without this information in box 4B will not be considered for this initiative.

Applications nonresponsive to terms of this NOSI will not be considered for the NOSI initiative.

Inquiries

Please direct all inquiries to the contacts in Section VII of the listed notice of funding opportunity with the following additions/substitutions:

Scientific/Research Contact(s)

Marilyn Miller, Ph.D.
National Institute on Aging (NIA)
Telephone: 301-496-9350
Email: millerm@nia.nih.gov

Michael Bennani, Ph.D.
National Institute on Aging (NIA)
Telephone: 301-448-0128
Email: michael.bennani@nih.gov