# Pulmonary Macrophage Transplantation for Pulmonary Alveolar Proteinosis

> **NIH NIH R01** · CINCINNATI CHILDRENS HOSP MED CTR · 2020 · $459,701

## Abstract

ABSTRACT
There is a significant gap in understanding how GM-CSF directs macrophage specification following pulmonary
macrophage transplantation (PMT). This is an important problem, because, without this crucial information, the
preclinical data will not adequately demonstrate PMT safety sufficient to gain approval to test PMT in humans.
The long-term goal is to develop PMT as therapy for patients with hereditary pulmonary alveolar proteinosis
(hPAP) aimed at restoring alveolar macrophage (AM) function. The objective here is to identify mechanism(s)
directing AM specification during PMT. The central Hypothesis is that AM specification is determined primarily
by factors in the alveolar microenvironment including 1) GM-CSF, which renders AM-specific DNA regulatory
elements accessible; and 2) surfactant phospholipid-derived fatty acids, which activate PPARγ to bind newly
accessible DNA and switch AMs from LXR-driven to PPARγ-driven specification (and cholesterol metabolism).
Our rationale is that by demonstrating GM-CSF directs macrophages to adopt a normal AM transcription profile
at single cell resolution (which `bulk' studies failed to show) will be crucial to establish PMT is safe. Guided by
our strong preliminary data, this hypothesis will be tested by pursuing three specific aims to determine 1) the
relationship between donor cell plasticity and therapeutic efficacy; 2) temporal dynamics of macrophage
engraftment, specification, and fate after PMT; and 3) cis-regulatory architecture governing AM specification. In
aim 1, myeloid cells of various developmental stages will be administered by PMT to Csf2raKO mice to deter-
mine the plasticity of cells capable of conferring therapeutic benefit. In aim 2, PMT of normal hematopoietic
stem/progenitor cell (HSPC) donors in Csf2raKO (or normal) mice with/without M-CSF inhibition will be done to
determine donor survival, proliferation, clonal expansion, phenotype and function. Cell population dynamics will
be tracked temporally by single-cell RNA-seq using Monocle. In aim 3, mouse or human HSPCs will be
cultured with/without GM-CSF and surfactant or DPPC and gene regulatory dynamics will be measured by
single-cell RNA-seq using Monocle to determine differentiation `trajectories'. DNA elements regulating cell
population dynamics will be identified by measuring chromatin accessibility by sci-ATAC-seq and using Cicero
to link DNA regulatory elements to the target genes they regulate. The proposed research is innovative
because it supports the development of a new therapy for hPAP based on restoring AM function rather than
physically removing surfactant (the current approach), and because it uses novel methods, software and
statistical tools to identify elements directing AM specification as `upstream regulators' or `downstream' targets,
which has not been possible with methods available previously. The proposed research is significant because
it will identify the alveolar determinants and transcriptional mec...

## Key facts

- **NIH application ID:** 9982374
- **Project number:** 5R01HL118342-07
- **Recipient organization:** CINCINNATI CHILDRENS HOSP MED CTR
- **Principal Investigator:** Bruce C Trapnell
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $459,701
- **Award type:** 5
- **Project period:** 2014-05-01 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9982374

## Citation

> US National Institutes of Health, RePORTER application 9982374, Pulmonary Macrophage Transplantation for Pulmonary Alveolar Proteinosis (5R01HL118342-07). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9982374. Licensed CC0.

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