Robust Rapid Cellular Metabolite Sensing Using Benchtop NMR and SABRE-Hyperpolarized [1-13C]Pyruvate

TL;DR

This paper introduces a benchtop NMR method using hyperpolarized pyruvate to rapidly and scalably monitor yeast metabolism in real time.

Contribution

A novel benchtop workflow using SABRE-hyperpolarized [1-13C]pyruvate for scalable, real-time metabolic phenotyping of live cells.

Findings

Hyperpolarized [1-13C]pyruvate enables detection of oxidative decarboxylation products CO2 and bicarbonate in yeast cells.

Metabolic activity remains detectable for over 300 seconds after pyruvate introduction.

The method allows pH estimation from CO2/bicarbonate equilibrium during active metabolism.

Abstract

Hyperpolarized NMR has emerged as a powerful analytical
technique
to significantly enhance targeted NMR signals, improving the sensitivity
for investigations of unique chemical and biological dynamics. Here,
we demonstrate the use of a hyperpolarization strategy based on Signal
Amplification By Reversible Exchange (SABRE) to generate highly reproducible
doses of a hyperpolarized [1-13C]­pyruvate probe for benchtop
characterization of yeast metabolism. This method allows rapid, scalable,
and benchtop preparation of biocompatible hyperpolarized solutions
suitable for live-cell experiments. We show that this production can
be dove-tailed into a modular, compact workflow to characterize real-time
metabolism in cell cultures, using Saccharomyces cerevisiae (Baker’s yeast) as a model organism. With high temporal resolution,
we show that this method can resolve the conversion of hyperpolarized
[1-13C]­pyruvate into oxidative decarboxylation products
CO2 and bicarbonate. This conversion exhibits sustained
and detectable metabolic activity for over 300 s after introduction
of the agent to the cells. We model the metabolite kinetics to show
decarboxylation activity and derive estimates of the pH over time
from the CO2 and bicarbonate (carbonic acid buffer system)
equilibrium to probe changes in the cellular environment during active
metabolism. These results highlight the utility of benchtop SABRE-hyperpolarized
[1-13C]­pyruvate as a scalable, specific probe for metabolic
phenotyping of living cells using compact, low-cost instrumentation
well-suited for future high-throughput applications across microbial
engineering, drug response profiling, and dynamic metabolic screening.

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