# Role of pH on Lineage Fate during Pluripotent Stem Cell Differentiation

> **NIH NIH F31** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 2021 · $37,838

## Abstract

ABSTRACT
Human pluripotent stem cells (hPSCs), including embryonic stem cells (hESCs) and induced pluripotent stem
cells (hiPSCs), complete a tightly controlled sequence of events during differentiation to recapitulate functional
cells from our bodies. This in vitro maturation process initiates by induction of mesoderm, ectoderm, and
endoderm lineage progenitors, and provides unique opportunities for disease modeling, drug screening, cell-
based therapies, and uncovering mechanisms in cell development. Yet, key obstacles remain and include (1)
inefficient PSC differentiation, (2) costly, labor-intensive protocols that promote genetic aberrations, and (3)
developmental immaturity and reduced functionality of terminal cells. Mechanistically, failed erasure of epigenetic
memory leaves residual marks that affects chromatin structure and gene expression from a hiPSC's somatic cell
type of origin. Thus, it is imperative to understand and implement optimized in vitro hPSC differentiation protocols
that reconstitute gene regulation and epigenome configuration programs matching in vivo cell counterparts to
achieve superior cell types for all applications that employ this remarkable system.
The role of cytokines, growth factors, and chemokines in driving hPSC differentiation is firmly established in cell
fate determination. Additionally, the facilitating role of metabolic flux and metabolite levels in reconfiguring the
epigenome to improve hPSC differentiation has recently been uncovered. Yet, a factor generated by metabolic
activity—acidification—has not been examined as a microenvironment stimulus controlling hPSC differentiation
despite its known roles in driving de- and re-differentiation during pathogenic and physiological development.
We recently discovered both differential metabolic programs and extracellular acidification rates during ectoderm
and mesoderm lineage differentiation. This confirms a direct connection between metabolism and acidification,
and further suggests a role for lowered pH in early lineage fate acquisition. The overall study goal here is to
uncover pH-dependent mechanisms in lineage-specific cell fate, and to ultimately exploit these processes for
optimized hPSC differentiation. To test the hypothesis that pH-sensitive mechanisms control early cell fate, we
will embark on 3 specific aims: (1) To determine the importance of pH in lineage partitioning under spontaneous
PSC differentiation in an embryoid body model. (2) To examine remodeling of epigenome configuration and
resulting lineage-specific gene expression to identify pH-sensitive regulators governing early differentiation
under low pH using transcriptomic and epigenetic screens. And (3) to study the feasibility of pH modulation to
enrich for functional mesoderm derivatives compared to current hPSC differentiation methodologies. Success in
these studies will open new pathways through pH manipulations for generating superior in vitro models of early
human development for n...

## Key facts

- **NIH application ID:** 10158520
- **Project number:** 5F31HD097960-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **Principal Investigator:** Vivian Lu
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $37,838
- **Award type:** 5
- **Project period:** 2019-07-15 → 2022-05-29

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10158520

## Citation

> US National Institutes of Health, RePORTER application 10158520, Role of pH on Lineage Fate during Pluripotent Stem Cell Differentiation (5F31HD097960-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10158520. Licensed CC0.

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