# Proximal Tubule Albumin Transport in Disease States.

> **NIH NIH R01** · INDIANA UNIVERSITY INDIANAPOLIS · 2021 · $436,531

## Abstract

Project Summary
While the clinical relevance of proteinuria, and especially albuminuria, has been well
documented the quantitative mechanistic contribution or role of different contributing
components to albuminuria remains an area of considerable excitement . In particular, the role
of proximal tubules in albumin reabsorption and reclamation is now known to be an important
determinant of the urinary barrier to albuminuria under physiologic and pathologic conditions.
Therefore, the present application proposes to dissect apart and quantify the contributions of the
known proximal tubule receptors cubilin/megalin and the fetal neonatal immunoglobulin receptor
(FcRn) for albumin. To accomplish this we will quantify the interactions of cubilin and FcRn with
albumin utilizing a stepwise and synergistic combination of biochemical solution binding assays,
cell culture uptake, trafficking and receptor knock out studies in human proximal tubule cells and
in vivo kidney studies using Munich Wistar Fromter rats with surface Glomeruli and 2-photon
dynamic imaging. Biochemical, structural, functional and mechanistic observations will be
interrelated to advance our present understanding of this clinically important phenomenon. Our
Overall Hypothesis is that by understanding how albumin interacts with and is affected
by these two receptors we will then understand how proximal tubule cells play
fundamental, interactive and inducible roles to try and maintain the physiological state
and minimize albuminuria. Our ultimate goal is to eventually develop a clinical approach
that will allow quantification of the origin of albuminuria as either a proximal tubule or
glomerular primary defect or a combination of both. This will allow for more specific
therapeutic targets and agents to be identified. To directly evaluate this hypothesis we have
developed the necessary techniques, approaches and cell and animal models to dissect,
quantify and understand the process of proximal tubule metabolism of albumin.

## Key facts

- **NIH application ID:** 10167690
- **Project number:** 5R01DK091623-10
- **Recipient organization:** INDIANA UNIVERSITY INDIANAPOLIS
- **Principal Investigator:** Bruce A Molitoris
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $436,531
- **Award type:** 5
- **Project period:** 2011-09-30 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10167690

## Citation

> US National Institutes of Health, RePORTER application 10167690, Proximal Tubule Albumin Transport in Disease States. (5R01DK091623-10). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10167690. Licensed CC0.

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