# Effects of microgravity on the structure and function of proximal and distal tubule MPS

> **NIH NIH UH3** · UNIVERSITY OF WASHINGTON · 2020 · $388,750

## Abstract

Abstract
Kidney dysfunction can precipitate serious medical conditions including proteinuria, osteoporosis, and
formation of kidney stones. These conditions occur more frequently, and progress faster, in crewmembers
stationed on the International Space Station. Current static models of the proximal and distal tubules are
unable to recapitulate cellular functions including protein reabsorption via megalin, vitamin D metabolic
bioactivation, and micro-crystal mediated injury response. We have developed a microphysiologic model of the
proximal tubule using primary proximal tubule epithelial cells (PTECs) that has successfully demonstrated
physiologic cellular structure/polarization, transport of glucose and drug substrates, bioactivation of inactive 25-
hydroxy vitamin D to 1α,25-dihydroxyvitamin D (which promotes beneficial bone remodeling), and physiologic
injury response to toxic exposure. We will expand this technology to develop a distal tubule epithelial cell
model (DTEC) which will be used to explore the pathophysiologic response to oxalate microcrystals.
Studying the proximal and distal tubules in the microgravity environment of the International Space Station
presents the unique opportunity to observe accelerated disease processes (proteinuria, osteoporosis, kidney
stones), which will facilitate the discovery of factors that contribute to the development and progression of
kidney diseases that cannot be observed on a conventional time scale. Therefore, the aims of this project are:
to determine the effects of microgravity on the polarized structural aspects (eg., ion and solute transporters) of
the kidney proximal and distal tubule epithelium in a 3D microphysiological system, to determine if Vitamin D
bioactivation/homeostasis within the kidney proximal tubule is compromised in response to extended exposure
to microgravity, and to create a disease-state models of proximal tubule proteinuria and distal tubule kidney
stone formation to evaluate the harmful or adaptive modulating effects of microgravity.
A better understanding of the factors and pathways that underlie proper cellular structure and the development
and progression of kidney diseases will uncover novel therapeutic targets that can be used in the development
of pharmacologic agents that can improve the health of Space Station crewmembers as well as the health of
the general public by preventing or reversing proteinuria, osteoporosis, and kidney stones.

## Key facts

- **NIH application ID:** 9890028
- **Project number:** 5UH3TR002178-04
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Jonathan Himmelfarb
- **Activity code:** UH3 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $388,750
- **Award type:** 5
- **Project period:** 2017-06-15 → 2023-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9890028

## Citation

> US National Institutes of Health, RePORTER application 9890028, Effects of microgravity on the structure and function of proximal and distal tubule MPS (5UH3TR002178-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9890028. Licensed CC0.

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