ALDOB K87 Lactylation: A Molecular Switch for Mitochondrial Fission and Remodeling in Pulmonary Hypertension

Study Background and Research Question

Pulmonary hypertension (PH) is a progressive and life-threatening disease characterized by pulmonary vascular remodeling, occlusive arteriopathy, and right ventricular failure. Despite advances in vasodilator therapies, reversal of the underlying vascular remodeling remains a major clinical challenge. Emerging research has highlighted the crucial role of metabolic reprogramming in pulmonary artery smooth muscle cells (PASMCs), particularly a shift from oxidative phosphorylation to aerobic glycolysis—a phenomenon reminiscent of the Warburg effect seen in cancer biology. However, the molecular mechanisms connecting metabolic rewiring to pathological PASMC proliferation in PH have remained elusive.

Key Innovation from the Reference Study

The recent article by Yi et al. (2026) introduces a novel mechanism by which nonhistone protein lactylation—specifically lysine-87 (K87) lactylation of aldolase B (ALDOB)—acts as a regulatory nexus between cellular metabolism and mitochondrial dynamics in PH (Yi et al., 2026). The study uncovers how hypoxia-induced ALDOB-K87 lactylation recruits dynamin-related protein 1 (DRP1) to mitochondria, facilitating mitochondrial fission and promoting PASMC proliferation and phenotypic switching. This work defines a new lactate–ALDOB–DRP1 axis, bridging metabolic alterations and structural remodeling in the pulmonary vasculature.

Methods and Experimental Design Insights

Yi et al. applied integrated lactylomic profiling of hypoxia-exposed human PASMCs, identifying a pronounced increase in ALDOB-K87 lactylation. To validate the functional significance of this modification, they combined in vitro PASMC assays with rodent PH models. Key techniques included:

• Quantitative lactylome sequencing to map protein lactylation changes under hypoxia.
• Genetic manipulation (mutagenesis of ALDOB K87) and pharmacological modulation to probe cause-effect relationships.
• Mitochondrial morphology analyses (e.g., confocal microscopy) for assessing mitochondrial fission/fusion states.
• Metabolic flux assays (glycolytic rate, lactate quantification) to characterize cellular reprogramming.
• Functional PASMC assays, including proliferation, migration, and phenotypic switching.
• Use of in vivo rodent models to examine the physiological impact of altered ALDOB lactylation on PH development.

Protocol Parameters

• Hypoxia exposure: Human PASMCs were cultured under 1% O₂ to induce PH-relevant metabolic stress.
• Lactylome profiling: Samples were harvested at defined time points (e.g., 24-48 h hypoxia) for proteomic analysis.
• Genetic manipulation: ALDOB K87R (lactylation-resistant) and K87Q (lactylation-mimetic) mutants were introduced via lentiviral transduction.
• Metabolic assays: Extracellular acidification rate (ECAR) and lactate production were measured following standard Seahorse and colorimetric protocols.
• In vivo validation: Rodent models received pharmacological inhibitors or gene delivery constructs to modulate ALDOB lactylation, with right ventricular systolic pressure (RVSP) and pulmonary vascular remodeling as endpoints.

Core Findings and Why They Matter

The study demonstrated that hypoxia-induced ALDOB-K87 lactylation amplifies glycolytic flux and fosters lactate accumulation, thereby reinforcing its own modification cycle. Mechanistically, lactylated ALDOB recruits DRP1 to mitochondria via sentrin/SUMO-specific peptidase 3 (SENP3)-mediated deSUMOylation of DRP1, driving mitochondrial fission. This mitochondrial fragmentation is directly linked to increased proliferation, migration, and phenotypic switching of PASMCs—hallmarks of vascular remodeling in PH.

Crucially, the authors found that Sirtuin 1 (SIRT1) acts as a delactylase for ALDOB, and its downregulation in PH sustains the pathogenic lactylation state. Genetic or pharmacologic suppression of ALDOB lactylation mitigated mitochondrial fission and slowed PH progression in animal models, while lactylation-mimetic mutants exacerbated disease phenotypes. These findings position ALDOB-K87 lactylation as a promising therapeutic target in PH.

Comparison with Existing Internal Articles

The mechanistic link between metabolic reprogramming and smooth muscle cell proliferation described by Yi et al. (2026) complements the system-level analyses offered in prior internal resources. For example, the article "PDGF-BB, Murine Recombinant Protein: Systems Biology & PH Remodeling" explores how murine recombinant PDGF-BB orchestrates cell proliferation and vascular remodeling in PH models, integrating mitogenic signaling with metabolic changes. Similarly, "PDGF-BB and Smooth Muscle Dynamics: Translating Mechanisms to Models" emphasizes the value of validated mitogen-driven assays to dissect smooth muscle responses, which aligns with the lactylation-driven PASMC proliferation described in the reference study.

Moreover, the internal review "ALDOB K87 Lactylation Regulates Mitochondrial Dynamics in PH" provides an accessible overview of the reference study's core findings, reinforcing the importance of ALDOB-mediated mitochondrial changes as a driver of pathological remodeling. Together, these resources contextualize the reference paper within a broader landscape of metabolic and mitogenic circuitry in PH research.

Limitations and Transferability

While the study by Yi et al. (2026) provides robust mechanistic evidence linking ALDOB K87 lactylation to mitochondrial and cellular remodeling in PH, several limitations warrant consideration. First, most experiments were conducted in isolated PASMCs and rodent models; the transferability of these findings to human PH pathobiology requires further validation. Second, although the study identifies SIRT1 as a delactylase, the broader landscape of enzymes regulating protein lactylation in vascular cells remains to be explored. Finally, the study does not address whether targeting ALDOB lactylation can reverse established vascular remodeling, which is a key translational question for PH therapy development.

Research Support Resources

For researchers aiming to model smooth muscle cell proliferation and metabolic reprogramming in PH, standardized reagents such as PDGF-BB, murine recombinant protein (SKU P1048) offer a validated approach to stimulate PASMC growth and mimic disease-relevant mitogenic signals. According to product data, this recombinant growth factor reliably induces dose-dependent proliferation of murine BALB/c 3T3 cells with high purity and low endotoxin levels, supporting robust cell proliferation assays and metabolic studies. The use of such reagents, in combination with advanced proteomic and metabolic techniques, can help investigators further dissect the interplay between metabolic rewiring, mitochondrial dynamics, and vascular remodeling in PH. APExBIO provides this recombinant PDGF-BB for research use only, facilitating high-precision modeling in preclinical studies.