Lactylation and exercise: A molecular link to disease alleviation (Review)

Introduction

Exercise provides a broad spectrum of health benefits. Research indicates that engaging in regular physical activity improves cardiovascular health, strengthens immune function, regulates metabolic processes and lowers the risk of chronic conditions such as diabetes and heart disease (1–5). Asdditionally, exercise enhances cognitive function, reduces stress and anxiety and promotes psychological well-being (6–9). It plays an essential role in maintaining bone and muscle health by increasing bone density and improving muscle strength (10–13). In summary, exercise serves as a crucial strategy for the prevention and management of numerous diseases, contributing to overall health and helping to slow the aging process (14–16). Despite these known benefits, the specific mechanisms through which exercise contributes to disease prevention and treatment remain incompletely understood.

During physical activity, muscles undergo intense exertion, producing energy that supports the ongoing exercise. In high-intensity activities, muscle cells may not receive enough oxygen, leading to an increase in anaerobic metabolism and lactate production (17–19). Lactate accumulation is a typical physiological response to exercise, commonly associated with muscle fatigue and diminished performance (18,19). Recent studies, however, suggest that lactate is not merely a metabolic byproduct but also plays a key physiological role, particularly in lactylation modifications (20–22). Lactylation refers to the process in which lactate molecules bind to specific protein sites through esterification, subsequently altering the function of the proteins (23–25). These lactylation modifications are crucial in cellular signaling, gene expression and metabolic regulation, influencing cellular adaptability, antioxidant defenses, and stress response mechanisms (26–28).

Studies indicate that exercise can regulate lactylation modifications, which subsequently affect cellular signaling and metabolic processes, thereby promoting overall health and aiding in disease relief. The aim of the present review is to summarize the current evidence on how exercise regulates lactylation modifications and to discuss the potential clinical relevance of these changes to disease prevention and treatment.

Lactate and lactylation modification

Lactate is an essential byproduct of metabolism, primarily generated in the cytoplasm, where it plays a fundamental role in glycolysis (29–31). When oxygen availability is limited or metabolic demands are heightened, cells convert glucose to pyruvate via glycolysis. In oxygen-deprived conditions, such as ischemia, pyruvate is unable to enter the mitochondria for oxidative phosphorylation, leading to its conversion into lactate. This metabolic process is catalyzed by lactate dehydrogenase (LDH), which transforms pyruvate into lactate and simultaneously facilitates the oxidation of NADH to NAD+, ensuring the uninterrupted progression of glycolysis (32–34).

The increase in lactate production is associated not only with the energy requirements of cells but also with the regulation by several critical proteins. Among these, LDH is a key enzyme in the synthesis of lactate (35,36), while other enzymes involved in glycolysis, such as glucose transporters (GLUT), pyruvate kinase M, hexokinase 2, aldolase A and phosphofructokinase, contribute to the regulation of this process (37–40). For instance, tumor cells commonly exhibit higher levels of LDH and increased enzymatic activity, leading to accelerated lactate production (41–43). Moreover, members of the GLUT family, including GLUT1 and GLUT3, facilitate glucose uptake, supplying the essential substrates for glycolysis (44,45). At the same time, lactate accumulation causes a decrease in local pH, which triggers the export of lactate through specific transporters, such as monocarboxylate transporters, thereby preventing excessive accumulation and maintaining the acid-base balance within the cell (46–49). The coordinated action of these proteins ensures proper regulation of lactate synthesis while maintaining cellular integrity and supporting the capacity of the cell to adapt to changes in the environment (Fig. 1).

Figure 1. Lactate production and intracellular metabolism involve several key processes. Initially, lactate enters the cytoplasm via the cell membrane through MCT, which originates from external cellular fluids. Lactate can be generated either through glycolysis or by the breakdown of glutamine. Once inside the cell, lactate metabolism follows two primary metabolic pathways. The first pathway converts lactate into pyruvate, which is subsequently transported to mitochondrial compartments for further oxidative processing within the TCA cycle. The second pathway involves converting lactate back into glucose through gluconeogenesis. Proteins involved in these metabolic processes include α-KG, MCT, PDH and components of the TCA cycle. MCT, monocarboxylate transporter; α-KG, α-ketoglutarate; PDH, pyruvate dehydrogenase; TCA, tricarboxylic acid; GLS, glutaminase.

Lactylation, similar to other post-translational modifications, influences both the activity and structure of polypeptides by adding lactyl groups to the side chains of amino acids. Lysine lactylation (Kla), a modification originating from lactate, was first discovered in 2019. This modification is highly conserved across various species and occurs in different cellular lineages (50–52). When lactate accumulates to a certain level, either intracellularly or extracellularly, it activates the lactylation process within the cell (53–55).

Lactylation is triggered when lactate acts as the primary substrate. Following the conversion of lactate into lactyl-CoA, the lactylation process commences (56,57). Specific acetyltransferases utilize lactyl-CoA as a substrate, transferring the lactyl group to lysine residues in both histone and non-histone proteins. This modification leads to alterations in their molecular structure and regulates their biological activities. The reactions are mediated by ‘writers’ such as P300/CREB-binding protein (58–60), methyltransferase-like 3 (61–63), lysine Acetyltransferase 2A and others (64–67). By contrast, ‘erasers’ such as histone deacetylases (HDACs) (68–71), histone demethylases (72) and sirtuins (73–75) remove the lactyl group from lysine residues, preventing the persistent effects of Kla. The coordinated activity of these ‘writers’ and ‘erasers’ maintains the equilibrium of protein lactylation, ensuring the stability of this modification within the organism (Fig. 2).

Figure 2. Enzymatic mechanisms controlling protein L-lactylation. Protein lactylation (KL-la), facilitated by the catalytic actions of KATs and AARSs, neutralizes the positive charge on lysine residues, leading to an increase of ~72 Da in mass. KAT catalyzes lactylation by utilizing lactyl-CoA, while AARSs rely on lactate and ATP to drive this process. Lactyl-CoA is synthesized through the catalytic action of enzymes such as GTPSCS and/or ACSS2. The removal of L-lactylation is mediated by enzymes, including KDAC, with contributions from zinc-dependent members, and it requires the activity of HDAC2 and NAD+-dependent SIRT. Furthermore, L-lactylation exists in two isomeric forms: KD-la and Kce, both arising from non-enzymatic reactions during glycolysis. Key molecules involved in these processes include dihydroxyacetone phosphate, methylglyoxal, lactylglutathione, glutamate-oxaloacetate transaminase, glucose transporter, mitochondrial pyruvate carrier, pyruvate dehydrogenase complex, acetyl-CoA and lactyl-CoA. KATs, lysine acetyltransferases; AARSs, aminoacyl-tRNA synthetase; KDAC, lysine deacetylase; HDAC, histone deacetylases; KD-la, D-lactylation; Kce, carboxyethylation; SIRTs, sirtuins.

Proteins prone to lactylation modifications include both histones and non-histone proteins (21,76–80). Initially, lactylation was observed in histones, which prompted extensive research into its regulation. For instance, Yue et al (81) revealed that lactylation at histone H3K9 (H3K9la) contributes to temozolomide resistance in glioblastoma via MLH1 intron retention, a mechanism facilitated by LUC7 like 2, pre-mRNA splicing factor. Specifically, H3K9la levels rise in glioblastoma cells after temozolomide treatment. Inhibition of glycolysis pharmacologically reduces H3K9la, thus increasing the sensitivity of the cell to temozolomide. The accumulation of H3K9la within an intronic region of the MLH1 gene locus causes intron retention, disrupting normal splicing and MLH1 function, which ultimately enhances resistance to temozolomide.

While considerable research has focused on histone proteins, substantial attention has also been directed toward non-histone proteins (82). For example, Tong et al (83) found that a diet lacking serine and glycine plays a dual role, both enhancing anti-tumor immunity and facilitating immune evasion through the lactylation of programmed death-ligand 1 (PD-L1). This dietary modification alters the metabolic conditions of the tumor microenvironment, stimulating anti-tumor immune responses and enhancing T cell-mediated tumor suppression. At the same time, it causes tumor cells to increase PD-L1 expression through lactylation, which in turn suppresses T cell-mediated immune responses and contributes to immune evasion. The lactylation of PD-L1 accumulates within tumor cells, leading to changes in its structure and function, thereby amplifying its immunosuppressive effects.

Exercise regulates lactylation modifications in the body

Lactate metabolism during physical exercise plays a role in various physiological processes. High-intensity or anaerobic exercise stimulates rapid energy production in muscles through glycolysis, resulting in a substantial accumulation of lactate (29). When lactate production exceeds the clearance capacity of the body, it accumulates in the muscles and bloodstream; however, lactate is not merely a ‘waste product’. Instead, it acts as an energy substrate, which can be reused by other tissues in the body, such as the heart, liver and resting or non-working muscles. It participates in oxidative metabolism or is converted into glucose (via the Cori cycle) for subsequent use (84) (Fig. 3). Studies have consistently shown that lactate accumulation promotes lactylation modifications, which play a role in regulating disease progression during exercise.

Figure 3. Inter-organ lactate shuttle during physical activity. During physical activity, lactate generated by white/glycolytic muscle fibers is transported between cells to red/oxidative muscle fibers, the heart, and the brain. From there, it is moved into the mitochondria for aerobic oxidation. MCT1, monocarboxylate transporter 1; MCT4, monocarboxylate transporter 4; TCA, tricarboxylic acid cycle.

Lactate has been identified as a key metabolite crucial for the body's adaptation to exercise training, playing a role in alleviating anxiety-like disorders. It has been observed that exercise-induced lactate enhances the lactylation of multiple synaptic proteins, among which synaptic vesicle-associated protein 91 (SNAP91) is essential for synaptic function. The lactylation of SNAP91 contributes to synaptic structural formation and neuronal activity within the medial prefrontal cortex, thereby promoting resilience to chronic restraint stress (78). Furthermore, research indicates that exercise can stimulate lactylation modifications in the brain, leading to improvements in both cognitive dysfunction and neuroinflammation in mice. This process involves an increase in lactate accumulation in the brain, which in turn facilitates histone lactylation in microglial cells, influencing their polarization and enhancing the reduction of cognitive dysfunction and neuroinflammation (85).

Exercise plays a notable role in regulating lactate accumulation within the brain, which in turn affects lactylation modifications. Additionally, one study reported that acute exercise induced dynamic alterations in histone acetyltransferases and HDACs in the hippocampus of mice (71). This observation suggests that exercise might influence lactylation modifications by adjusting the dynamic balance between ‘writers’ and ‘erasers’ involved in lactylation regulation. However, other research has indicated that high-intensity interval training (5 days per week for 6 weeks) in mice leads to an increase in lactate levels and promotes neuroplasticity in the brain due to lactate accumulation, yet no significant changes in the extent of lactylation modifications were observed (86). These findings imply that the impact of lactate on disease progression may not be solely dependent on lactylation modification regulation. Despite these insights, the research by these authors has several limitations. For example, the authors primarily relied on exogenous lactate supplementation to demonstrate the role of lactate, without incorporating an in vivo validation step to confirm glycolysis inhibition. Furthermore, the detection of lactylation modifications was based solely on results from a relatively rare antibody brand, potentially leading to false-negative outcomes.

Skeletal muscles and the skeletal system function as an integrated musculoskeletal unit during exercise. Skeletal muscles generate force through contraction, whereas the skeleton provides support and stability for movement. Regular physical activity can improve skeletal-muscle strength and physical function (12,13) and, through mechanical loading, improve or preserve bone mineral density (10,11). Together, these adaptations support physical performance and overall health.

Recent research indicates that exercise can enhance both skeletal muscle strength and bone density by regulating lactylation modifications in muscles and bones. For instance, the study by Chang et al (87), first identified differences in lactylation modifications of skeletal muscle proteins post-exercise, although the authors did not explore the significance of these changes. By contrast, Meng et al (88) conducted further research, confirming the mechanism. Their study demonstrated that exercise induces histone lactylation modifications (H3K9la) in skeletal muscles, which regulates the expression of aging-related genes, ultimately preventing skeletal muscle aging.

In addition to histone lactylation, post-exercise lactate accumulation has been shown to stimulate non-histone lactylation modifications. For example, Jia et al (89) demonstrated that lactate accumulation after exercise promotes lactylation modifications of class III phosphatidylinositol 3-kinase (Vps34), enhancing its binding with Beclin1, autophagy-related protein 14-like protein and UV radiation resistance associated protein, thus increasing Vps34 lipid kinase activity. This, in turn, promotes autophagy and maintains skeletal muscle homeostasis. Notably, a study suggested that lactate accumulation following exercise can induce mTOR lactylation modifications, inhibiting mTOR pathway activation and promoting autophagy to maintain skeletal muscle homeostasis (90). These findings emphasize not only the role of lactylation modifications in regulating skeletal muscle homeostasis but also highlight the diversity of targets involved in this process.

Furthermore, preclinical evidence suggests that exercise-associated lactate may promote osteogenesis through lactylation. In an ovariectomized mouse model, Wu et al (91) demonstrated that endothelial cell-derived lactate increased H3K18la in bone mesenchymal stem cells and upregulated COL1A2, COMP, ENPP1 and TCF7L2, which promoted osteoblast differentiation; exercise partially rescued the osteoporotic phenotype. Similarly, in treadmill- and tail-suspension mouse models and mechanically stretched bone mesenchymal stem cells, Dai et al (92) found that mechanical stress increased IER3 activity, lactate content and lactylation levels. IER3 knockdown inhibited force-induced osteogenic differentiation and prevented the increases in lactate and lactylation, while LDHB was identified as a downstream target of IER3.

Additionally, a recent study reported that lactylation of the non-histone protein UDP-glucose 6-dehydrogenase suppressed glycosaminoglycan synthesis and activated MAPK signaling, thereby aggravating osteoarthritis (93). A second study showed that LDHA-mediated H3K18 lactylation enhanced TPI1 transcription in chondrocytes, and LDHA deficiency alleviated cartilage injury in osteoarthritis mice (94). Together, these findings suggest that lactylation may contribute to osteoarthritis progression. However, neither study examined exercise-induced lactate directly; therefore, they do not establish that post-exercise lactate regulates cartilage cells (93,94). Overall, current evidence indicates that lactylation has context-dependent effects in musculoskeletal tissues, with potentially protective roles in exercise models but detrimental roles in osteoarthritis models.

Exercise plays a notable role in reducing body fat and preventing chronic conditions such as cardiovascular diseases. Both aerobic exercise and strength training are particularly effective in promoting fat metabolism, improving cardiovascular health, decreasing the risk of coronary heart disease and enhancing overall well-being (95–97). Lactylation modifications have been identified in these processes. In the context of cardiovascular diseases, research indicates that exercise-induced lactylation of endothelial methyl-CpG binding protein 2 (Mecp2) inhibits atherosclerosis via the Ereg/MAPK signaling pathway (98). Additionally, studies have shown that exercise-induced lactylation of Mecp2 in macrophages reduces atherosclerosis by promoting M2 macrophage polarization (99). These findings suggest that exercise may help prevent atherosclerosis by enhancing lactylation modifications. Atherosclerosis serves as an early stage in myocardial ischemia-reperfusion injury. Notably, a study has suggested that exercise can mitigate myocardial ischemia-reperfusion injury by regulating lactylation modifications. From a mechanistic perspective, exercise-induced lactylation of YTHDF2 in cardiomyocytes prevents apoptosis, thus reducing myocardial ischemia-reperfusion injury (100).

Exercise is commonly used for fat loss, primarily by increasing energy expenditure and improving adipose-tissue metabolism (95,96). In a preclinical high-intensity interval-training study, training increased pan-lactylation of proteins in inguinal white adipose tissue. In 3T3-L1 adipocytes, lactate treatment increased fatty acid synthase lactylation, inhibited fatty acid synthase activity, and reduced palmitate and triglyceride synthesis, suggesting that fatty acid synthase lactylation may contribute to high-intensity interval training-associated fat loss (101).

Exercise is widely acknowledged for its effectiveness in preventing disease progression, yet excessive exercise can still have detrimental effects on health, with mechanisms linked to lactylation modifications. For instance, research has shown that excessive exercise leads to an accumulation of lactate in skeletal muscles, which is then transferred to the liver. This causes the lactylation of SH3 domain-containing protein 3 (SORBS3) and triggers liquid-liquid phase separation (LLPS). The LLPS of SORBS3 enhances its interaction with flotillin 1, selectively promoting the sorting of F-box protein 2 into small extracellular vesicles, referred to as ‘lactosomes’. These lactosomes induce apoptosis in hepatocytes and activate hepatic stellate cells via the MCL1-BAX/BAK signaling pathway, ultimately contributing to the development of liver fibrosis (102).

To summarize, moderate and appropriate exercise plays a notable role in regulating mood and mental well-being, promoting muscle homeostasis and preventing osteoporosis through the modification of lactylation. Additionally, evidence suggests that such exercise can effectively prevent as well as treat the initiation and progression of myocardial ischemia-reperfusion injury (Table I).

Table I. Mechanisms of lactylation modulation by exercise.

Table I.

Mechanisms of lactylation modulation by exercise.

Effects of exercise on diseases	Target tissues	Exercise form	Lactylation modification sites	Mechanism of action	(Refs.)
Enhance stress resistance	Brain	Treadmill exercise (60 min daily, 14 days)	SNAP91	Exercise promotes lactate levels in the brain and lactylation modifications, with SNAP91 lactylation enhancing synaptic structure formation and neuronal activity in the medial prefrontal cortex.	(78)
Improve cognitive dysfunction and neuroinflammation	Brain	Treadmill exercise (50 min daily, 5 days a week, 8 weeks)	Histone	Exercise promotes the accumulation of lactate in the brain, which then enhances histone lactylation modifications in microglial cells, influencing microglial cell polarization.	(85)
Promote brain neuroplasticity	Brain	High-intensity interval training (5 days a week, 6 weeks)	Not proven	Unclear	(86)
Inhibit skeletal muscle aging	Skeletal muscle	Long-duration treadmill running (3 times a week, 30 min per session, for 2 months)	H3K9la	Exercise promotes histone lactylation and inhibits skeletal muscle aging by regulating age-related pathways.	(88)
Maintain skeletal muscle homeostasis	Skeletal muscle	Acute swimming (20 min daily, 5 days)	Vps34	Post-exercise lactate accumulation promotes Vps34 lactylation, which enhances the binding of Vps34 with Beclin1, ATG14L, and UVRAG, stimulating Vps34 lipid kinase activity and promoting autophagy to maintain skeletal muscle homeostasis.	(89)
Maintain skeletal muscle homeostasis	Skeletal muscle	Treadmill exercise (5 min on days 1 and 2, 40 min on day 3)	mTOR	Post-exercise lactylation of mTOR inhibits mTOR pathway activation and promotes skeletal muscle autophagy.	(90)
Inhibit osteoporosis	Bone	Treadmill exercise (8 min per session, 5 days a week, 8 weeks)	H3K18la	Exercise promotes histone lactylation and inhibits osteoporosis by promoting osteoblast differentiation.	(91)
Inhibit osteoporosis	Bone	Treadmill exercise (20–55 min daily, 5 days a week, 8 weeks)	Unclear	Exercise promotes lactylation modifications after exercise, which may alleviate osteoporosis.	(92)
Inhibit atherosclerosis	Vessels (endothelial cells)	Moderate-intensity treadmill exercise (30–60 min daily, 3–5 days a week, 12 weeks)	Mecp2	Exercise-induced endothelial Mecp2 lactylation inhibits atherosclerosis through the Ereg/MAPK signaling pathway.	(98)
Inhibit atherosclerosis	Vessels (macrophages)	Treadmill exercise (60 min daily, 5 days a week, 8 weeks)	Mecp2	Exercise-induced endothelial Mecp2 lactylation inhibits atherosclerosis by promoting macrophage M2 polarization.	(99)
Inhibit myocardial ischemia-reperfusion injury	Heart	Swimming (twice daily, starting with 10 min per session, for 4 weeks)	YTHDF2	Exercise-induced YTHDF2 lactylation in cardiomyocytes inhibits apoptosis, thereby suppressing myocardial ischemia-reperfusion injury.	(100)
Reduce fat	Adipose tissue	High-intensity interval training (5 days a week, 8 weeks)	FASN	Lactate produced by high-intensity interval training increases the pan-lactylation level of proteins in inguinal white adipose tissue. Fatty acid synthase lactylation inhibits de novo lipogenesis, inducing fat reduction.	(101)

Translational potential and clinical challenges of exercise-related lactylation

Clinical trials and meta-analyses support the benefits of exercise for cardiovascular health, depressive symptoms and bone health (1–3,6,7,10). However, direct human evidence linking exercise to defined protein lactylation events remains limited. In two human skeletal-muscle biopsy studies, neither acute nor chronic resistance training, nor a single bout of endurance exercise, produced a significant increase in global skeletal-muscle protein lactylation (103,104). Therefore, lactylation cannot yet be used to guide exercise prescription or serve as a therapeutic target in clinical practice.

The most immediate translational opportunity is to determine whether site-specific lactylation events can serve as biomarkers of exercise response. Future human studies should use repeated sampling around well-characterized exercise interventions, targeted lactyl-proteomic assays and clinically meaningful outcomes to establish whether a lactylation signature predicts or mediates the benefits of exercise.

Several challenges must be addressed before clinical implementation. Lactylation is dynamic and cell-type specific, and measurements from blood or bulk tissue may not reflect the relevant target cells. Assay specificity, sampling time, exercise dose, diet, medication use and disease stage may also influence the results. In addition, associations between lactate, lactylation and clinical outcomes do not establish causality or justify broad pharmacological manipulation of lactylation.

Overall, current evidence supports lactylation as a promising mechanistic and biomarker framework rather than an established clinical target. Translation will require reproducible, target-specific evidence in humans showing that modulation of a defined lactylation event improves outcomes beyond those achieved by exercise alone.

Conclusion and future perspectives

Lactylation modifications have attracted growing interest as a notable post-translational modification mechanism, particularly due to their involvement in exercise-induced disease prevention and treatment. Exercise influences lactate metabolism and lactylation modifications, which play a role in enhancing physical fitness, improving cardiovascular and pulmonary health and promoting mental well-being. Moreover, exercise offers new insights into the molecular mechanisms regulating intracellular metabolism, gene expression, and antioxidant defense. By modulating the activity of various proteins, lactylation modifications affect cellular adaptive responses, contributing to the relief of diseases such as cardiovascular conditions, skeletal muscle aging, osteoporosis and neurological diseases. Additionally, an expanding body of research indicates that lactate, once considered just a metabolic byproduct, actively participates in complex physiological regulatory processes, providing new perspectives for applying exercise therapy in the treatment of diseases.

Current findings also indicate that the effects of lactylation are context dependent. In exercise models, lactylation has been associated with potentially beneficial adaptations in skeletal muscle, bone and cardiovascular tissues, whereas studies of osteoarthritis suggest that specific lactylation events may contribute to disease progression. These observations highlight the importance of defining the relevant tissue, target protein and exercise context before drawing therapeutic conclusions.

Future studies should identify site-specific and cell-specific lactylation events that change reproducibly in response to well-characterized exercise interventions. Standardized sampling windows, targeted lactyl-proteomic assays and clinically meaningful outcomes will be needed to determine whether these events mediate exercise benefits or can serve as biomarkers of response. Rigorous human studies are also required to establish causality, safety and clinical value before lactylation can be considered a therapeutic target.

In conclusion, lactylation provides a useful molecular framework for investigating how exercise-related lactate signaling may influence disease-relevant pathways. Its clinical application will require robust human evidence demonstrating target specificity, causality and added value beyond established exercise interventions.

Acknowledgements

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Funding

Funding: No funding was received.

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Authors' contributions

LW conceptualized the review, provided project management and supervision, and wrote, reviewed and edited the manuscript. JW drafted, reviewed and edited the manuscript and prepared the figures. All authors read and approved the final version of the manuscript. Data authentication not applicable.

Ethics approval and consent to participate

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Patient consent to participate

Not applicable.

Competing interests

The authors declare that they have no competing interests.

References