ALDOB K87 Lactylation Drives Mitochondrial Fission in Pulmonary Hypertension

Study Background and Research Question

Pulmonary hypertension (PH) is a progressive and life-threatening disorder characterized by the remodeling and narrowing of pulmonary vessels, ultimately causing right ventricular failure. Despite advances in vasodilator therapies, the five-year survival rate remains suboptimal, largely due to limited efficacy in reversing vascular remodeling. Recent studies have highlighted the importance of metabolic reprogramming in pulmonary artery smooth muscle cells (PASMCs) during PH, particularly a shift from oxidative phosphorylation to aerobic glycolysis, also known as the Warburg effect. However, the molecular mechanisms linking metabolic disturbances to structural vascular changes have been incompletely understood.

The reference study by Yi et al. (Communications Biology, 2026) investigates whether post-translational lactylation of aldolase B (ALDOB) at lysine 87 (K87) serves as a critical regulator of mitochondrial dynamics and metabolic remodeling in PH pathogenesis.

Key Innovation from the Reference Study

This work introduces a novel mechanistic axis in PH: hypoxia-induced ALDOB-K87 lactylation acts as a bridge between enhanced glycolytic flux and the stimulation of mitochondrial fission in PASMCs. The authors demonstrate that this specific lactylation event amplifies glycolytic output, increases lactate accumulation, and creates a positive feedback loop reinforcing further protein lactylation. Notably, the study elucidates how ALDOB lactylation recruits dynamin-related protein 1 (DRP1) to mitochondria via sentrin/SUMO-specific peptidase 3 (SENP3)-mediated deSUMOylation of DRP1, directly facilitating mitochondrial fragmentation. In addition, the work identifies sirtuin 1 as a delactylase whose downregulation in PH sustains pathological lactylation.

Methods and Experimental Design Insights

The researchers combined integrated lactylomic profiling with functional validation in both cellular and animal models. Key approaches included:

• Lactylome sequencing of hypoxic human PASMCs to identify post-translational modifications.
• Validation of ALDOB-K87 lactylation in rodent PH models using site-directed mutagenesis and pharmacological modulation.
• Assessment of glycolytic flux, lactate production, and mitochondrial dynamics through biochemical assays and high-resolution microscopy.
• Manipulation of sirtuin 1 expression to dissect its role as an ALDOB delactylase.
• Functional assays to measure PASMC proliferation, migration, and phenotypic switching under different genetic and metabolic backgrounds.

This integrative design allowed the authors to track the interplay between metabolic rewiring, post-translational protein modification, and pathogenic cellular behaviors central to PH.

Core Findings and Why They Matter

The study’s principal findings can be summarized as follows:

• Hypoxia amplifies ALDOB-K87 lactylation in PASMCs, which promotes a glycolytic phenotype with increased lactate production (Yi et al., 2026).
• Lactylated ALDOB recruits DRP1 to mitochondria, facilitated by SENP3-dependent deSUMOylation, leading to increased mitochondrial fission—a hallmark of hyperproliferative PASMCs in PH.
• Sirtuin 1 acts as a delactylase for ALDOB, but its downregulation in PH preserves the pro-fission, pro-proliferative state.
• Genetic or pharmacological suppression of ALDOB lactylation attenuates mitochondrial fission and PASMC proliferation, thereby reducing PH progression in vivo.
• Lactylation-mimetic ALDOB mutants exacerbate PH phenotypes, underscoring the causative role of this modification in disease pathogenesis.

These discoveries are significant because they directly connect metabolic adaptation (enhanced glycolysis and lactate production) to the structural and functional changes in PASMCs that drive PH. The identification of the lactate–ALDOB–DRP1 axis provides new mechanistic targets for intervention, moving beyond symptomatic vasodilation to address the underlying drivers of vascular remodeling.

Comparison with Existing Internal Articles

Several internal commentaries and guides have previously highlighted the importance of ALDOB K87 lactylation and its impact on mitochondrial dynamics in PH. For example, a detailed overview at cy5-nhs-ester-for-2d-electrophoresis.com summarizes how this specific post-translational modification orchestrates mitochondrial fission and metabolic reprogramming. Another resource at prestainedprotein.com discusses practical workflows for studying smooth muscle cell proliferation, emphasizing the utility of PDGF-BB as a mitogenic stimulus in vascular remodeling assays.

The present reference study advances these discussions by providing molecular detail on how ALDOB K87 lactylation links metabolic flux to mitochondrial fragmentation and by validating these findings in both cellular and animal models. Furthermore, it adds mechanistic depth regarding the role of sirtuin 1 as a delactylase and the feedback between lactate accumulation and sustained lactylation, complementing earlier insights into the metabolism–epigenetics interface in PH (protein-g-beads.com).

Limitations and Transferability

While this study establishes a compelling causal link between ALDOB K87 lactylation and mitochondrial fission in PH, several limitations merit consideration:

• The work primarily utilizes rodent models and cultured human PASMCs, leaving open questions about the universality of these mechanisms in diverse patient populations and other forms of vascular disease.
• Although the molecular axis is well-characterized, the translation of these findings into clinically effective therapies will require further investigation, particularly concerning the safety and specificity of targeting ALDOB lactylation in vivo.
• The focus on PASMCs does not exclude potential contributions from other cell types in the pulmonary vasculature, such as endothelial or immune cells.

Nonetheless, the mechanistic clarity of the lactate–ALDOB–DRP1 axis provides a strong foundation for future translational research targeting metabolic and mitochondrial pathways in PH.

Protocol Parameters

• Hypoxia induction in PASMCs: Maintain cells at 1% O₂ for 48–72 hours to model PH-related metabolic stress, as outlined in the reference study.
• Assessment of lactylation: Use site-directed mutagenesis to generate K87R (non-lactylatable) and K87Q (lactylation-mimetic) ALDOB constructs for functional analysis.
• PDGF-BB mitogen activity assays: Apply murine recombinant PDGF-BB at concentrations below 2 ng/ml to stimulate PASMC proliferation or migration in vitro, in alignment with protocols described in internal workflows.
• Mitochondrial fission quantification: Employ high-resolution microscopy and DRP1 immunostaining to evaluate mitochondrial morphology post-treatment.
• Sirtuin 1 modulation: Utilize siRNA or pharmacological inhibitors/activators to probe the role of sirtuin 1 in ALDOB delactylation and mitochondrial dynamics.

Research Support Resources

To facilitate similar research workflows, investigators can employ PDGF-BB, murine recombinant protein (SKU P1048), a well-characterized mitogen for smooth muscle and connective tissue cell proliferation assays. According to the product information, this recombinant growth factor provides robust, dose-dependent stimulation of murine 3T3 cell proliferation with an ED₅₀ of less than 2 ng/ml, supporting high-fidelity modeling of vascular remodeling signals in vitro. For detailed protocols and troubleshooting in cell proliferation assay with PDGF-BB, see the workflow guide at prestainedprotein.com. This product is intended for research use only and can be integrated into studies aiming to dissect PDGFR-α and PDGFR-β signaling or to model smooth muscle cell proliferation in the context of PH-associated metabolic reprogramming.