Lactylation‑mediated ferroptosis: A novel mechanism and therapeutic prospects in human diseases (Review).

Post-translational modifications (PTMs) increase proteomic functional diversity by covalently adding functional groups, regulating the proteolytic cleavage of subunits or the degradation of entire proteins. These include glycosylation, ubiquitination, small ubiquitin-like modification, acetylation, phosphorylation and palmitoylation, affecting nearly all aspects of cell biology and pathology ( 1 - 5 ). Lactate, once considered a waste product of glucose metabolism, has been revealed in recent years as not only a key circulating energy substrate, but also as a signaling molecule. Notably, it profoundly regulates gene expression and cell fate through a novel PTM, lysine lactylation (Kla) ( 6 - 10 ). In 2019, Zhang et al ( 11 ) first reported histone Kla in Nature, inaugurating a new era in lactate biology research. Kla has rapidly emerged as a research hotspot in life sciences, with its mechanisms and pathological significance providing transformative insights in fields such as cancer, immunology and neurological diseases ( 11 - 16 ). Kla involves the transfer of a lactyl group to the amino group of lysine residues, a process regulated by a series of enzymes and metabolites, including lactate, 'writer' enzymes, 'reader' proteins and 'eraser' enzymes ( 17 ). Lactate accumulation is the core trigger for Kla, with its level being positively associated with the degree of Kla modification ( 18 , 19 ). Under the action of 'writers', L-lactyl-CoA derived from lactate is transferred to proteins, initiating Kla. Erasers remove L-lactyl-CoA from proteins to terminate Kla, while 'reader' proteins recognize Kla and transduce signals to downstream targets ( 20 - 23 ). The concept of ferroptosis was first proposed in 2012, referring to a unique form of programmed cell death triggered by iron-dependent lipid peroxidation pathways. It participates in multiple physiological and pathological processes and is prevalent in various diseases ( 24 - 28 ). In recent years, significant progress has been made in understanding the mechanisms of ferroptosis, including iron homeostasis imbalance, lipid peroxidation and the disruption of antioxidant systems ( 29 - 33 ). Furthermore, numerous factors regulate cellular sensitivity to ferroptosis under pathological conditions, thereby influencing disease progression ( 27 ). System xCT is an antiporter, with solute carrier family (SLC)7A11 as a key component, responsible for transporting cysteine and glutamate. It increases cellular cysteine uptake, which is converted to glutathione (GSH) under the action of thioredoxin reductase 1. Glutathione (GSH) peroxidase 4 (GPX4) relies on GSH as a substrate to enhance its activity, promoting the conversion of phospholipid hydroperoxides (PL-OOH) to lipid alcohols. Thus, system xCT prevents ferroptosis by reducing PL-OOH accumulation. Erastin and RAS-selective lethal 3 (RSL3, a ferroptosis inducer), as inhibitors of system xCT and GPX4, respectively, promote ferroptosis ( 34 - 36 ). An imbalance in iron homeostasis is another classical pathway in ferroptosis, primarily regulated by a network involving transferrin receptor 1 (TFR1), iron regulatory protein (IRP)1 and IRP2, affecting cellular iron uptake, storage and release ( 30 , 37 , 38 ). Reactive oxygen species (ROS) generation and phospholipid peroxidation require numerous metabolic enzymes, with iron acting as their catalyst and essential element. Iron-dependent Fenton reactions rapidly amplify PL-OOH and generate various reactive radicals, inducing ferroptosis in cancer cells ( 39 - 41 ). Unrestricted lipid peroxidation is a hallmark of ferroptosis. Acyl-CoA synthetase long-chain family member 4 (ACSL4) is a key enzyme converting polyunsaturated fatty acids (PUFAs) to phospholipids (PUFA-PEs). PUFA-PEs promote intracellular lipid peroxide accumulation under the action of various enzymes. Phospholipids rich in PUFAs in cell membranes and phospholipid peroxidation are considered the direct executors of ferroptosis ( 42 , 43 ). Lactate is the driver of lactylation and is associated with lactylation levels ( 11 ). Lactate production and removal maintain electron flux through specific pathways, including NADH conversion to NAD + and H + , and lactate dehydrogenase (LDH)-mediated lactate conversion. These reduced coenzymes generate electrons upon oxidation via mitochondrial respiration or lactate fermentation, maintaining redox balance ( 44 , 45 ). Lactate accumulation can also promote intracellular fatty acid synthesis by activating key enzymes and supplying precursors ( 46 , 47 ). Studies have also demonstrated that cellular redox imbalance and fatty acid metabolism are associated with ferroptosis ( 48 , 49 ). Increasing evidence indicates that lactylation regulates ferroptosis either by mediating gene transcription via histone modifications or by directly modifying key ferroptosis enzymes, altering their activity and inducing ferroptosis, thereby influencing disease pathogenesis. Notably, lactylation exhibits significantly higher dynamics than other PTMs, with its level directly regulated by microenvironmental lactate concentration. This characteristic renders Kla a crucial hub connecting cellular metabolic state and epigenetic regulation, particularly in diseases with active glycolysis (e.g., tumors and inflammation). However, a systematic description of the Kla-ferroptosis axis is currently lacking. Therefore, the present review discusses the regulation of ferroptosis by lactylation and summarizes its impact on diseases, including inflammation, degenerative diseases, cancer and ischemia-reperfusion (I/R) injury. The present review aimed to provide insight for future research and disease treatment.

Notably, the cross-regulatory mechanisms between lactylation and other programmed cell death pathways are increasingly becoming a focus of research. Beyond ferroptosis, Kla may modulate processes such as necroptosis, apoptosis and autophagy by modifying key proteins, forming a complex network governing cell fate decisions ( 134 ). For instance, preliminary studies suggest that lactate accumulation can influence the activity of receptor interacting serine/threonine kinase 3, a core necroptosis protein, via lactylation, thereby modulating cell death patterns in inflammatory diseases ( 135 ). In tumor models, Kla may promote cell survival and resistance to therapy by inhibiting apoptotic signaling pathways (e.g., BCL-2 family proteins) or enhancing the stability of autophagy-related proteins (e.g., light chain 3) ( 136 , 137 ). Such cross-regulation not only reveals the central role of metabolic-epigenetic networks in multiple death pathways, but also provides new insight for developing combination therapies targeting lactylation. Future studies are required to systematically elucidate the site-specific functions of Kla in necroptosis, apoptosis and autophagy, and clarify the dynamic interactions among these pathways to more comprehensively evaluate the therapeutic potential of targeting Kla. However, the field still faces multiple challenges: Structural similarities between lactylation-regulating enzymes and other acyltransferases/deacetylases necessitate highly specific drugs to avoid off-target effects on PTMs such as acetylation; the dual role of the Kla-ferroptosis axis in diseases (e.g., promoting injury in sepsis while exerting protection in spinal cord injury) calls for cell- and microenvironment-specific targeted delivery systems; notably, dynamic detection technologies for lactylation remain underdeveloped, requiring novel in vivo imaging probes to facilitate patient stratification and treatment monitoring ( 108 , 112 , 138 ). Further studies are thus required to focus on designing highly specific modulators, constructing intelligent delivery systems and validating dynamic lactylation biomarkers. This may broaden the understanding of cell fate regulation mechanisms and may provide novel paradigms for the treatment of cancer, as well as inflammatory, degenerative and ischemic diseases.

As an emerging epigenetic regulatory mechanism, the precise detection of lactylation is crucial for elucidating its functions in physiological and pathological processes. The detection of lactylation primarily relies on mass spectrometry and specific antibody-based detection. Mass spectrometry, particularly liquid chromatography-tandem mass spectrometry, serves as the core method, enabling the highly sensitive identification of specific sites and quantification of modification levels. This method involves digesting protein samples with proteases to generate a mixture of peptides. These peptides are then separated by liquid chromatography and are subjected to precise mass detection and sequence analysis via mass spectrometry. This allows for the unbiased identification of specific lactylation sites and their absolute or relative quantification. However, challenges include potential misidentification due to the similar chemical properties of lactylation and acetylation, and the need for higher-resolution instruments due to low modification abundance ( 11 , 100 , 104 - 107 ). Specific antibody-based detection utilizes antibodies targeting specific modification sites. Techniques such as western blot analysis for quantification, immunofluorescence for observing intranuclear distribution and co-immunoprecipitation for exploring protein interactions enable the in situ and intuitive observation of the subcellular localization and tissue distribution characteristics of lactylation. This approach provides advantages, such as operational simplicity and high sensitivity; however, it is associated with risks of non-specific binding and the limited availability of commercial antibodies ( 108 - 112 ). The comprehensive application of these methods provides key technical support for elucidating the role of lactylation in tumorigenesis and development, laying the foundation for its clinical translation.