# Analysis of receptor-mediated transcytosis pathways implicated in Alzheimer's disease

> **NIH NIH R01** · UNIVERSITY OF MINNESOTA · 2021 · $226,253

## Abstract

PROJECT SUMMARY
The blood-brain barrier (BBB) is a highly selective barrier comprised of brain microvascular endothelial cells
(BMECs) that presents a major bottleneck for drug delivery to treat disorders such as Alzheimer's disease (AD).
In addition to preventing therapeutics from entering the brain, BBB dysregulation is observed in the earliest
stages of AD, leading to a decreased ability to clear amyloid beta (Aβ) that largely contributes to the accumulation
of Aβ in the brain. Studying receptor-mediated transcytosis in the BBB is central to both discovering novel routes
for delivery of therapeutics into the brain for treatment of AD and developing a mechanistic understanding of
early pathological changes to the BBB that lead to eventual Aβ accumulation. The parent grant is focused on
developing novel high-throughput screening technologies to identify the full set of transcytosis receptors in the
intestinal epithelium for applications in oral drug delivery. The objective of the proposed supplemental work is to
apply these technologies to a stem cell-derived model of the BBB. The use of human induced pluripotent stem
cell-derived BMECs will enable studies of transcytosis in the AD BBB using cell lines with varying copy numbers
of the APOE-ε4 allele, which is the greatest genetic risk factor for late-onset AD. While the precise connections
between the APOE-ε4 allele and BBB dysfunction are not well characterized, it has been shown that expression
of apoE4, encoded by APOE-ε4, alters Aβ transcytosis across the BBB, inhibiting its proper clearance. The
proposed research consists of two aims: (1) identification of novel receptors for transcytosis-mediated drug
delivery to the brain for AD treatment and (2) identification of Aβ receptors in BMECs. In the first aim, BMECs
will be differentiated from hiPSC lines containing zero, one or two copies of the APOE-ε4 allele, and a novel
transcytosis-based directed evolution method, as detailed in the parent grant, will be used to discover new protein
ligands that are able to transcytose the BMEC monolayer. The receptors mediating transcytosis of these ligands
will then be identified as potential targets for delivery of therapeutics to the AD BBB. In the second aim,
crosslinking mass spectrometry (CLMS) will be utilized to identify the full repertoire of Aβ receptors in BMECs
differentiated from iPSC lines with varying APOE-ε4 status. These studies will enable analysis of any genotype-
specific differences in expression of known Aβ receptors, such as LRP1 and RAGE, as well as discovery of new
Aβ receptors among the different BMECs. These pilot studies will be incorporated into a new R01 proposal to
elucidate new mechanisms of transcytosis related to Aβ clearance as well as delivery of therapeutic payloads to
the brains of AD patients.

## Key facts

- **NIH application ID:** 10285761
- **Project number:** 3R01DK114453-04S1
- **Recipient organization:** UNIVERSITY OF MINNESOTA
- **Principal Investigator:** Casim Sarkar
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $226,253
- **Award type:** 3
- **Project period:** 2018-07-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10285761

## Citation

> US National Institutes of Health, RePORTER application 10285761, Analysis of receptor-mediated transcytosis pathways implicated in Alzheimer's disease (3R01DK114453-04S1). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10285761. Licensed CC0.

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