ALDOB K87 Lactylation: A Central Driver of Mitochondrial Fission and Metabolic Remodeling in Pulmonary Hypertension

Study Background and Research Question

Pulmonary hypertension (PH) is a severe, progressive disorder marked by the remodeling of pulmonary vasculature, leading to increased pulmonary arterial pressure and right ventricular failure. Despite current therapies, long-term outcomes remain poor, largely due to limited understanding of the molecular mechanisms driving vascular remodeling and smooth muscle cell proliferation. Recent research has pointed to metabolic reprogramming—specifically, a shift toward aerobic glycolysis (the Warburg effect)—as a key factor in promoting pathological cell proliferation within the pulmonary artery wall. However, the upstream regulators connecting metabolic changes to structural vascular alterations in PH are not fully elucidated (reference).

Key Innovation from the Reference Study

The article by Yi et al. delivers a breakthrough by identifying a novel post-translational modification—lactylation of aldolase B (ALDOB) at lysine 87 (K87)—as a crucial orchestrator of mitochondrial fission and metabolic reprogramming in PH. The study demonstrates that hypoxia-induced ALDOB-K87 lactylation amplifies glycolytic flux, increasing lactate production and triggering a self-reinforcing cycle of protein lactylation. Mechanistically, this modification acts by recruiting dynamin-related protein 1 (DRP1) to mitochondria via sentrin/SUMO-specific peptidase 3 (SENP3)-mediated deSUMOylation, thereby directly promoting mitochondrial fragmentation and exacerbating pulmonary artery smooth muscle cell (PASMC) proliferation. This lactate–ALDOB–DRP1 axis bridges metabolic changes with mitochondrial dynamics, offering a new paradigm for understanding and potentially targeting PH progression (reference).

Methods and Experimental Design Insights

The authors employed a multi-tiered approach integrating lactylome sequencing and proteomic profiling to survey lactylation landscapes in hypoxic human PASMCs and in rodent models of PH. Site-specific mass spectrometry pinpointed a marked increase in ALDOB-K87 lactylation under hypoxic conditions. Functional assays, including PASMC proliferation and migration measurements, were complemented by genetic and pharmacological manipulations: ALDOB mutants either mimicking or blocking K87 lactylation, and Sirtuin 1 (SIRT1) knockdown or overexpression to modulate delactylase activity. Mitochondrial morphology was quantified by fluorescence microscopy, and the recruitment of DRP1 was assessed via co-immunoprecipitation and immunofluorescence colocalization. In vivo, the study validated findings using rodent PH models subjected to hypoxic exposure, with assessment of pulmonary vascular remodeling and right ventricular hypertrophy (reference).

Protocol Parameters

• cell proliferation assay | 1–10 ng/ml PDGF-BB | PASMCs, smooth muscle cell proliferation | Standard range for stimulating proliferation in vascular remodeling models | workflow_recommendation
• Lactylation quantification | site-specific mass spectrometry | PASMCs under hypoxia | Detecting post-translational modifications in metabolic reprogramming studies | paper
• Genetic manipulation | ALDOB K87R/K87Q mutants | in vitro PASMCs, in vivo rodent models | Assessing function of specific lactylation sites in mitochondrial dynamics | paper
• Mitochondrial fission imaging | fluorescence microscopy (mito-tracker) | PASMCs | Quantifying mitochondrial fragmentation under variable lactylation conditions | paper
• PASMC migration | wound healing/Transwell assays | PASMCs | Evaluating migration in response to metabolic or mitochondrial perturbations | paper

Core Findings and Why They Matter

The study’s central finding is that ALDOB K87 lactylation functions as a molecular switch that links hypoxia-driven glycolytic metabolism with accelerated mitochondrial fission and PASMC proliferation. Specifically:

• Hypoxia elevates ALDOB-K87 lactylation, which in turn amplifies glycolytic flux and lactate accumulation.
• This modification recruits DRP1 to mitochondria via SENP3-mediated deSUMOylation, promoting mitochondrial fragmentation.
• Enhanced mitochondrial fission is directly linked to increased PASMC proliferation, migration, and phenotypic switching, key processes in pulmonary vascular remodeling.
• SIRT1 acts as a delactylase for ALDOB; its downregulation in PH sustains pathogenic lactylation, suggesting a regulatory checkpoint.
• Genetic or pharmacological attenuation of ALDOB lactylation reduces mitochondrial fission and mitigates PH progression in vivo, while lactylation-mimetic mutants worsen pathological features (reference).

These insights provide a mechanistic explanation for how metabolic derangements drive smooth muscle cell proliferation and underscore lactylation as a potential target for future PH therapies.

Comparison with Existing Internal Articles

Several internal resources have previously explored the role of murine recombinant PDGF-BB as a mitogen and metabolic modulator in pulmonary hypertension, focusing on its ability to stimulate smooth muscle and connective tissue cell proliferation and its applications in cell proliferation assays. For example, "Advanced Mechanisms and Applications in Vascular Remodeling Research" discusses the mitogenic effects of PDGF-BB and the importance of PDGFR-α and PDGFR-β signaling in vascular remodeling contexts. The current study by Yi et al. extends these insights by elucidating an upstream metabolic-epigenetic axis (lactylation of ALDOB) that converges on pathways previously associated with PDGF-BB-induced cell proliferation. While the internal articles provide protocol-driven guidance for using recombinant growth factors in proliferation assays, the reference study offers a mechanistic rationale for targeting metabolic-epigenetic modifications alongside established mitogenic cues in PH models.

Limitations and Transferability

While this study delineates a compelling lactylation-driven mechanism in PH using both in vitro and in vivo models, several limitations warrant consideration:

• The findings are primarily based on rodent PH models and cultured PASMCs; direct evidence from human tissues in clinical PH is still lacking.
• The complex interplay between multiple post-translational modifications and their cumulative impact on mitochondrial and metabolic pathways remains to be fully mapped.
• The therapeutic targeting of ALDOB lactylation or SIRT1 activity requires additional validation for safety and specificity in translational settings.

Nevertheless, the identification of the ALDOB–lactylation–DRP1 axis provides a valuable molecular framework for designing future studies and developing targeted interventions for PH (reference).

Research Support Resources

For researchers aiming to model metabolic reprogramming or smooth muscle cell proliferation in pulmonary hypertension, PDGF-BB, murine recombinant protein (SKU P1048) offers a reliable reagent for stimulating PDGFR-β signaling and proliferation in PASMCs. Its well-characterized mitogen activity and compatibility with cell proliferation assays make it a valuable tool for experimental workflows investigating vascular remodeling and metabolic interventions (source: product_spec). For advanced assay design and troubleshooting, refer to protocol-driven internal guides such as Enhancing Cell Proliferation Assays with PDGF-BB and Applied Workflows with Murine Recombinant PDGF-BB in Vascular Research.