The Protective Role of ILC3s Glycolysis in Myocardial Ischemia-Reperfusion Injury: Unveiling Metabolic and Immune Regulatory Mechanisms

1. Introduction

MIRI refers to the further damage to myocardial cells and tissues when blood flow is restored after myocardial ischemia. This damage not only occurs during ischemia but also intensifies after blood flow is restored[1]. The pathological and physiological mechanisms of MIRI are closely related to oxidative stress[2], apoptosis[3], inflammatory response[4], metabolic disorders, and myocardial cell damage and repair,[5,6] which severely affect cardiac function and structure, leading to various cardiovascular diseases such as heart failure, arrhythmia, and cardiac arrest, posing a significant threat to patients' quality of life and life expectancy. Therefore, the treatment of MIRI is a major challenge in the medical field. The mainstream treatment plans include drug therapy (such as drugs to improve myocardial energy metabolism[7], antioxidants[8], calcium channel blockers[9]), ischemic preconditioning and postconditioning[10], and stem cell therapy (such as mesenchymal stem cells)[11]. However, these treatments have limitations such as unsatisfactory effects, large individual differences, high operational requirements, unresolved safety and stability issues, and immune rejection reactions. Despite the difficulties in research and treatment of MIRI, the medical community continues to tackle this problem. It has been found that ILC3s have anti-inflammatory[12], immune cell balance regulation[13], promotion of cardiomyocyte regeneration, enhancement of cardiomyocyte survival, and potential activation of endogenous protective mechanisms in MIRI[14]. The key to the function of ILC3s is the glycolysis process. Its effects on glucose uptake, metabolic pathways, metabolic sensing molecules, signal transduction pathways, cytokine secretion, metabolic product signaling, antioxidant enzyme regulation, reactive oxygen species generation and clearance, and apoptosis signaling pathways can influence the prognosis of MIRI. Therefore, the glycolysis of ILC3s is of great significance for the occurrence and development of MIRI and the formation of new treatment plans for MIRI.

2. ILC3s and ILC3s Glycolysis

2.1. Introduction to ILC3s

ILC3s originate from common lymphoid progenitors and are mainly enriched in the intestinal mucosa, liver, kidneys, and other areas[15]. ILC3s have unique molecular characteristics, including key transcription factors[16,17], cytokine secretion[18], receptors[19], and signaling pathways[20,21], as well as metabolic features. These characteristics enable ILC3s to play important roles in maintaining tissue homeostasis, regulating immune responses, and promoting tissue repair. ILC3s have the following functions:

Anti-inflammatory effects: During MIRI, the inflammatory response is a key factor leading to myocardial damage. ILC3s can regulate the inflammatory response by secreting anti-inflammatory cytokines. For example, ILC3s can secrete interleukin-22 (IL-22), and Jun Yan et al[22]. have proven that ILC3s and intestinal T cells secrete the cytokine IL-22 to promote epithelial integrity and protect against intestinal pathogens[23]. They can inhibit the production of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)[24].Regulation of immune cell balance: ILC3s can interact with other immune cells to maintain immune cell balance. In the MIRI environment, they can regulate the functions of T cells and macrophages. For instance, ILC3s can inhibit over-activated macrophages from releasing inflammatory mediators while promoting the generation of macrophage subsets with repair functions, thereby reducing myocardial inflammatory damage and facilitating myocardial repair. Priscillia Bresler et al[25]. have proven that T cells regulate ILCs residing in lymph nodes in a tissue- and subset-specific manner.Promotion of cardiomyocyte regeneration: ILC3s can secrete various growth factors, such as vascular endothelial growth factor (VEGF)[26]. VEGF can stimulate myocardial angiogenesis, providing better blood supply for cardiomyocytes, which is conducive to the repair and regeneration of damaged cardiomyocytes. P.B.J Burton et al[27]. have proven that VEGF is an effective stimulant for myocardial ischemia in standard cardiopulmonary bypass coronary artery bypass grafting (CPB-CABG) and off-pump coronary artery bypass grafting (OP-CABG), which may affect postoperative graft endothelialization and cardiovascular hemodynamics.Enhancement of cardiomyocyte survival: ILC3s enhance the anti-apoptotic ability of cardiomyocytes through paracrine mechanisms by secreting cell-protective factors. In MIRI, cardiomyocytes are threatened by apoptosis due to various factors such as oxidative stress[28] and calcium overload[29]. The cell-protective factors secreted by ILC3s can help cardiomyocytes resist these harmful factors and increase the survival rate of cardiomyocytes.Activation of potential endogenous protective mechanisms: When MIRI occurs, the body attempts to initiate a series of protective programs to mitigate the damage. ILC3s may activate some endogenous protective signaling pathways, such as the PI3K-Akt pathway, through signal transmission with cardiomyocytes. The activation of these pathways can regulate the metabolism of cardiomyocytes and inhibit apoptosis, thereby exerting a protective effect in the early stage of MIRI[30,31]（Figure a）.

2.2. ILC3s Glycolysis is Key to ILC3s Function（Figure b）

2.2.1. Glucose Uptake and Metabolic Pathways

ILC3s glycolysis plays a crucial role in the normal functioning of ILC3s, including anti-inflammatory effects, immune cell balance regulation, cardiomyocyte regeneration promotion, enhancement of cardiomyocyte survival, and activation of potential endogenous protective mechanisms[32,33,34]. Specifically, ILC3s take up glucose through glucose transporter 1 (GLUT1) and metabolize it through pathways such as glycolysis and oxidative phosphorylation. After glucose enters the cell, it is metabolized through the glycolysis process to generate adenosine triphosphate (ATP), providing energy for the cell. In myocardial ischemia-reperfusion injury, the glycolysis activity of ILC3s is enhanced, which helps maintain the energy supply of cardiomyocytes. Metabolic products can provide energy and biosynthetic precursors for ILC3s, thereby maintaining their normal cell activity and function. ILC3s take up glucose through GLUT1, and after glucose enters the cell, the glycolysis process begins, including glucose phosphorylation, G-6-P isomerization, F-6-P phosphorylation, F-1,6-2P cleavage, conversion of phosphoglycerate, and conversion of phosphoglycerate to glyceraldehyde-3-phosphate (G-3-P) under the catalysis of phosphoglycerate mutase. This step is reversible, but the continuous consumption of G-3-P drives the reaction towards G-3-P, generating ATP five times further. Pyruvate is then metabolized; under anaerobic conditions, pyruvate is converted to lactate by lactate dehydrogenase, simultaneously regenerating nicotinamide adenine dinucleotide (NAD+), to maintain the continuous glycolysis. Under aerobic conditions, pyruvate enters the mitochondria and is converted to acetyl-CoA by pyruvate dehydrogenase, entering the tricarboxylic acid (TCA) cycle for further oxidative phosphorylation. The metabolic state of ILC3s can affect their signal transduction pathways through metabolic sensing molecules such as AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR). The activation of AMPK can regulate the energy metabolism and cell activity of ILC3s, while mTOR regulates their proliferation and metabolism[35,36].

2.2.2. Cytokine Secretion and Metabolic Product Signaling

ILC3s glycolysis is associated with the secretion of cytokines such as interleukin-17 (IL-17) and IL-22 and the signaling of metabolic products[31,37]. For instance, in myocardial ischemia-reperfusion injury, IL-17 mainly promotes cardiomyocyte apoptosis, neutrophil infiltration, and inflammatory response, exacerbating myocardial damage[38]. In contrast, IL-22 exerts anti-inflammatory and cardioprotective effects, promoting cardiomyocyte regeneration and repair and reducing cardiomyocyte apoptosis. Chen Yang et al[39]. found that IL-22 can prevent angiotensin II-induced cardiomyocyte apoptosis by enhancing the activity of superoxide dismutase (SOD), blocking the decrease in mitochondrial membrane potential, inhibiting reactive oxygen species (ROS) production, and preventing the release of cytochrome C. ILC3s glycolysis can also participate in the transcriptional regulation or post-translational modification of IL-17 and IL-22 genes, thereby regulating their secretion levels[40]. Metabolic products of ILC3s (such as lactate and pyruvate) can bind to receptors on the surface of cardiomyocytes, such as monocarboxylate transporters (MCT), lactate receptors (GPR81), and pyruvate transporters (MPC), to regulate the metabolism and functional state of cardiomyocytes, thereby affecting the repair process of myocardial ischemia-reperfusion injury. Han She et al[41]. found that dexmedetomidine upregulates the phosphorylation of nuclear receptor subfamily 3 group C member 1 (NR3C1), downregulates pyruvate dehydrogenase kinase 4 (PDK4), and reduces lactate production and malate dehydrogenase 2 (MDH2) lactation. Ji Hae Jun et al[42]. found that the downstream protective mechanisms of pyruvate ethyl ester in myocardial ischemia-reperfusion injury include reducing ROS-mediated inflammasome activation, upregulation of NOD-like receptor 3 (NLRP3) inflammasome and related pathways, partly by inhibiting hypoxia-induced extracellular signal-regulated kinase (ERK) and p38 phosphorylation. The transcription factor Tox2 plays an important role in maintaining the gut microbiota, and the metabolism of ILC3s is crucial for it[43].

2.2.3. Synergistic Effects of Cardiomyocyte Protection and Immune Regulation

ILC3s glycolysis interacts with cardiomyocytes and other immune cells. For example, signal molecules produced by ILC3s glycolysis can affect the metabolic state, antioxidant capacity, and apoptosis process of cardiomyocytes, thereby exerting protective or damaging effects in myocardial ischemia-reperfusion injury[44,45]. The interaction between ILC3s and other immune cells such as T cells and macrophages can also be regulated by glycolysis. Metabolic products or metabolic sensing signals can affect the signal transmission and functional synergy between ILC3s and other immune cells, thereby regulating the immune and inflammatory responses in myocardial ischemia-reperfusion injury[46,47].

2.2.4. Antioxidant Enzyme and Reactive Oxygen Species Regulation

ILC3s glycolysis is involved in the regulation of antioxidant enzymes and the generation and clearance of reactive oxygen species. For example, ILC3s glycolysis may regulate the expression and activity of antioxidant enzymes (such as SOD, CAT) to modulate the oxidative stress levels in myocardial ischemia-reperfusion injury[48]. ILC3s glycolysis may produce a certain amount of ROS, and its metabolic products and metabolic sensing signals can also affect the clearance mechanisms of ROS. Blanda Di Luccia et al[33]. found that ILC3 activation depends on a metabolic program that combines glycolysis with ROS production. ROS has a double-edged sword effect in myocardial ischemia-reperfusion injury; moderate levels of ROS may promote cardiomyocyte protection and repair, while excessive ROS levels can lead to cardiomyocyte damage and death. Studies have shown that apoptosis and ROS are regulated by miR-182-5p through targeting STK17A to prevent myocardial ischemia-reperfusion injury[49,50].

2.2.5. Regulation of Apoptosis Signaling Pathways

ILC3s glycolysis is involved in the regulation of apoptosis signaling pathways and the control of apoptosis-related genes. For example, ILC3s glycolysis may regulate the expression and function of Bcl-2 family proteins by affecting apoptosis signaling pathways (such as the mitochondrial pathway, death receptor pathway) to regulate apoptosis in myocardial ischemia-reperfusion injury. ILC3s glycolysis can regulate apoptosis in myocardial ischemia-reperfusion injury by affecting the transcription and translation of apoptosis-related genes (such as Caspase family genes, Bcl-2 family genes)[51]. Huizi Liu et al[52]. found that in the miR-484 treatment group, the apoptosis index of cardiomyocytes in the ischemic area decreased, the membrane potential increased, and the expression of caspase-3/9 was significantly reduced.

Figure b.

Figure b.

2.3. Regulation Mechanisms of ILC3s Glycolysis

The rational regulation of ILC3s glycolysis is crucial for ensuring that the energy metabolism and function of ILC3s are in an appropriate state. It is regulated by the following aspects:1.Regulation of Glycolysis Pathway: It is regulated by hexokinase (HK)[53], phosphofructokinase (PFK)[54], and pyruvate kinase (PK)[55]. The role of metabolic sensors: Metabolic sensors such as AMPK and mTOR can affect the metabolic state of ILC3s by regulating the activity of key enzymes in the glycolysis pathway[56,57].2.Regulation of Oxidative Phosphorylation Pathway: Regulation of mitochondrial function[58]: The mitochondrial function of ILC3s can affect their energy supply by regulating the oxidative phosphorylation pathway. Jingzeng Cai et al[59]. found that di(2-ethylhexyl) phthalate (DEHP) can impair mitochondrial function and damage cardiomyocytes through the interleukin-6 (IL-6), Janus kinase (JAK) signal transduction, and signal transducer and activator of transcription 3 (STAT3) pathway. Changes in the morphology, quantity, and functional state of mitochondria can affect the metabolism and immune function of ILC3s[33,60]. Regulation of the electron transport chain: Changes in the activity of complexes in the electron transport chain can regulate the energy metabolism and oxidative stress levels of ILC3s, thereby affecting their role in myocardial ischemia-reperfusion injury[61].3.Regulation of Metabolic Sensing Signaling Pathways: Regulation by cytokines and hormones: Hormones such as insulin and glucagon can affect the function of ILC3s by regulating their glycolysis pathway[62]. These hormones can activate or inhibit specific signaling pathways, such as glucagon regulating transcription factors nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1), and insulin regulating the PI3K/AKT signaling pathway to regulate the metabolic state of ILC3s. Interaction of intracellular signaling pathways: The interaction of signaling pathways such as PI3K/Akt and MAPK can regulate the glycolysis and immune function of ILC3s, thereby affecting their regulatory role in myocardial ischemia-reperfusion injury[63,64,65] （Figure c）.

3. Multiple Regulatory Mechanisms of ILC3s Glycolysis in Myocardial Ischemia-Reperfusion Injury

3.1. Pathophysiology of Myocardial Ischemia-Reperfusion Injury（Figure d）

When blood flow is restored after myocardial ischemia, further damage occurs to myocardial cells and tissues, mainly including the following changes:

Oxidative Stress: During reperfusion, the sudden increase in oxygen leads to the production of a large amount of reactive oxygen species (ROS) by mitochondria and other organelles, such as superoxide anions, hydrogen peroxide, and hydroxyl radicals[66,67]. Excessive ROS can attack the lipids, proteins, and DNA of cell membranes, leading to the destruction of cell structure and function, increasing cell membrane permeability, reducing enzyme activity, and causing DNA damage, ultimately leading to myocardial cell damage and death. Peiying Pai et al[66]. found that superoxide anion scavengers reduced hypoxia-induced Fas-related death domain, such as Fas ligand, Fas death receptor, Fas-dependent apoptotic pathway, such as activated caspase-8 and activated caspase-3, and mitochondrial-dependent apoptotic pathway, such as Bad, activated caspase-9 and activated caspase-3, endonuclease G (EndoG), apoptosis-inducing factor (AIF), and TUNING positive cell apoptosis, while enhancing cardiac survival pathways. Soochan Bae et al. found that reducing the expression levels of NADPH oxidase (NOX) 2 and 4 is beneficial for reducing hydrogen peroxide generation after MIRI and has protective significance for cardiomyocytes.

Apoptosis: Myocardial ischemia-reperfusion injury activates various apoptosis signaling pathways, such as the mitochondrial pathway and death receptor pathway. In the mitochondrial pathway, the mitochondrial membrane potential decreases, cytochrome c is released, and caspase-9 is activated; in the death receptor pathway, the binding of death receptors (such as Fas receptors) on the cell surface with ligands activates caspase-8. The activation of these signaling pathways leads to a cascade reaction of caspase family proteins, ultimately activating caspase-3 and leading to cardiomyocyte apoptosis[68,69].

Inflammatory Response: Myocardial ischemia-reperfusion injury induces the infiltration of inflammatory cells (such as neutrophils and macrophages). These inflammatory cells release a large amount of pro-inflammatory cytokines, such as TNF-α, IL-1β, and IL-6, which not only damage cardiomyocytes but also affect myocardial structure and function through processes such as promoting fibrosis and vascular remodeling[70,71].

Metabolic Disorders: During ischemia, the energy metabolism of cardiomyocytes mainly relies on glycolysis. After reperfusion, due to impaired mitochondrial function, the oxidative phosphorylation pathway cannot be restored in time, leading to insufficient energy supply of cardiomyocytes. Metabolic products (such as lactate) produced during ischemia cannot be cleared in time after reperfusion, further affecting the metabolism and function of cardiomyocytes[72].

Cardiomyocyte Damage and Repair: Myocardial ischemia-reperfusion injury leads to necrosis and apoptosis of cardiomyocytes, destruction of myocardial tissue structure, and decreased myocardial contractility. After injury, the body initiates a series of repair processes, including cardiomyocyte regeneration, fibrosis, and angiogenesis. However, due to the limited regenerative capacity of cardiomyocytes, the fibrosis process often dominates, leading to increased myocardial stiffness and further deterioration of cardiac function[73].

Figure d.

Figure d.

3.2. Effects of ILC3s Glycolysis on Myocardial Ischemia-Reperfusion Injury

3.2.1. Glucose Uptake and Metabolic Pathways

Glucose Uptake: ILC3s take up glucose through glucose transporter GLUT1. In myocardial ischemia-reperfusion injury, glucose uptake is crucial for maintaining the energy supply of cardiomyocytes. The increased expression of GLUT1 in cardiomyocytes can promote glucose uptake and glycolysis, thereby enhancing the regenerative capacity of cardiomyocytes and the cardiac repair response. During ischemia-reperfusion injury, the increased glucose uptake by ILC3s can provide more energy for cardiomyocytes, helping them resist damage and promote repair[74].Metabolic Pathways: Glycolysis is one of the main metabolic pathways of ILC3s glycolysis. In myocardial ischemia-reperfusion injury, the activation of the glycolysis pathway can rapidly produce ATP, providing immediate energy for cardiomyocytes. The activity regulation of key enzymes such as HK and PFK is crucial for the glycolysis process[75]. The enhancement of glycolysis can promote the proliferation and regeneration of cardiomyocytes. In addition to glycolysis, oxidative phosphorylation is also an important metabolic pathway for ILC3s glycolysis. During the reperfusion stage, the recovery of mitochondrial function and the activation of the oxidative phosphorylation pathway are important for maintaining the long-term energy supply and functional recovery of cardiomyocytes. However, the recovery of mitochondrial function takes time, so the rapid energy supply of glycolysis is particularly important in the early stage of reperfusion[76,77]

3.2.2. Metabolic Sensing Molecules and Signal Transduction

Metabolic Sensing Molecules: AMPK is activated when cellular energy is insufficient and regulates various metabolic pathways to maintain cellular energy homeostasis. There are certain differences in the functions and regulatory mechanisms of AMPK in different cell types, and these differences have important specific effects in the process of MIRI. AMPK is activated when energy is insufficient. The glycolysis state of ILC3s can be regulated through the activation of AMPK. In myocardial ischemia-reperfusion injury, the activation of AMPK can promote glucose uptake and glycolysis, enhancing the energy supply of cardiomyocytes. Additionally, AMPK can reduce ROS production by regulating the expression of antioxidant enzymes, thereby alleviating oxidative stress damage. The glycolysis state of ILC3s can affect through the regulation of the mTOR signaling pathway. In myocardial ischemia-reperfusion injury, the activity regulation of mTOR can affect the proliferation and autophagy processes of cardiomyocytes, thereby influencing the survival and functional recovery of cardiomyocytes[78,79].Signal Transduction Pathways: The glycolysis of ILC3s can affect the function of cardiomyocytes by regulating signaling pathways such as PI3K/Akt, JAK2/STAT3, and Nrf2/HO-1. Xiaqiong Wang et al[80]. found that the specific deletion of Gpr34 encoding lysophosphatidylserine (LysoPS) receptor in ILC3s or the inhibition of downstream PI3K-AKT or ERK inhibited IL-22 production in response to apoptotic neutrophils. Zhou Liang et al[81]. found that ILC3s increased the expression of programmed cell death 1 (PD-1) and subsequent interleukin-17A (IL-17A) production, directly activating myofibroblasts and fibrotic niche formation. In myocardial ischemia-reperfusion injury, the activation of the above signaling pathways can promote the survival of cardiomyocytes, reduce inflammatory responses, reduce cell apoptosis, and improve the energy supply of cardiomyocytes by regulating glycolysis pathways, thereby affecting the regeneration and repair processes of cardiomyocytes.

3.2.3. Cytokine Secretion and Metabolic Product Signaling

Cytokine Secretion: IL-17 can promote inflammatory responses and cardiomyocyte apoptosis, while IL-22 has anti-inflammatory and cardioprotective effects. The glycolysis state of ILC3s can affect the transcriptional regulation or post-translational modification of IL-17 and IL-22 genes to regulate their secretion levels. By regulating the secretion of these two cytokines, the glycolysis of ILC3s can regulate inflammatory responses and the protection and repair of cardiomyocytes. Other cytokines affected: The glycolysis of ILC3s may also affect the secretion of other cytokines, such as TNF-α, IL-6, etc. These cytokines also have important regulatory roles in myocardial ischemia-reperfusion injury, regulating inflammatory responses, cell proliferation, and apoptosis processes, thereby affecting the damage and repair of cardiomyocytes. Metabolic Product Signaling: Metabolic products of ILC3s glycolysis, such as lactate and pyruvate, can regulate the metabolism and functional state of cardiomyocytes by binding to receptors on the surface of cardiomyocytes. For example, lactate can act as a signaling molecule and regulate the energy metabolism and antioxidant capacity of cardiomyocytes by binding to monocarboxylate transporters (MCT) on the surface of cardiomyocytes, thereby affecting the repair process of myocardial ischemia-reperfusion injury. Additionally, during ischemia, the reverse activity of succinate dehydrogenase (SDH) leads to the accumulation of succinate. During reperfusion, succinate is rapidly oxidized, producing a large amount of ROS, causing oxidative stress damage to cardiomyocytes[82]. The glycolysis of ILC3s may regulate the metabolism and clearance of succinate, affecting the oxidative stress levels of cardiomyocytes, thereby exerting a protective role in myocardial ischemia-reperfusion injury. Moreover, metabolic products of ILC3s glycolysis can not only directly affect cardiomyocytes but also regulate immune and inflammatory responses by interacting with other immune cells (such as T cells, macrophages). For example, metabolic products can regulate the polarization state of macrophages, promoting their shift to an anti-inflammatory phenotype (M2 type), thereby exerting a protective role in myocardial ischemia-reperfusion injury[83].

3.2.4. Immune Regulation and Antioxidant Effects

Interaction with Other Immune Cells: Signal molecules produced by ILC3s glycolysis can affect the metabolic state, antioxidant capacity, and apoptosis process of cardiomyocytes. For example, metabolic products and cytokines secreted by ILC3s can regulate the mitochondrial function and energy metabolism of cardiomyocytes, enhance the antioxidant capacity of cardiomyocytes, reduce oxidative stress damage, and may also regulate the apoptosis process of cardiomyocytes by regulating apoptosis signaling pathways in cardiomyocytes, thereby affecting the repair of myocardial ischemia-reperfusion injury. Additionally, the interaction between ILC3s and other immune cells such as T cells and macrophages may also be regulated by glycolysis. For example, metabolic products and cytokines secreted by ILC3s can regulate the proliferation and differentiation of T cells, promote the generation of anti-inflammatory T cells (such as Treg cells), inhibit inflammatory responses[84]; at the same time, ILC3s can also regulate the polarization state of macrophages, promoting the shift of macrophages to an anti-inflammatory phenotype (M2 type), thereby exerting a protective role in myocardial ischemia-reperfusion injury[70].Regulation of Antioxidant Enzyme Expression and Activity: Metabolic products and metabolic sensing signals in the glycolysis process of ILC3s can activate the Nrf2 signaling pathway, thereby promoting the expression of antioxidant enzymes (such as superoxide dismutase SOD, glutathione peroxidase GPx, catalase CAT, etc.). By clearing reactive ROS, oxidative stress damage is alleviated, and cardiomyocytes are protected[85]. Antioxidant enzymes and cell protection: The enhanced activity of antioxidant enzymes can effectively clear ROS in cardiomyocytes, prevent oxidative damage of ROS to cell membrane lipids, proteins, and DNA, and maintain the integrity of cell structure and function. Generation of reactive oxygen species: ILC3s glycolysis can promote the generation of ROS by affecting mitochondrial function and the electron transport chain, etc. For example, during reperfusion, mitochondria produce a large amount of ROS due to the activation of the oxidative phosphorylation pathway, such as superoxide anions, hydrogen peroxide, and hydroxyl radicals. Clearance of reactive oxygen species: ILC3s glycolysis can enhance the ability of cardiomyocytes to clear ROS by regulating the expression and activity of antioxidant enzymes. For example, by activating the Nrf2 signaling pathway to promote the expression of antioxidant enzymes, the excessive ROS can be effectively cleared, preventing damage to cardiomyocytes.

3.2.5. Regulation of Apoptosis Signaling Pathways

ILC3s glycolysis can regulate the mitochondrial pathway of apoptosis signaling pathways by affecting mitochondrial function. For example, metabolic products and metabolic sensing signals can regulate mitochondrial membrane potential and the opening of mitochondrial permeability transition pores (PTP), thereby affecting the release of cytochrome c. After cytochrome c is released, it can activate caspase-9, triggering a caspase cascade reaction, leading to cardiomyocyte apoptosis. By regulating the mitochondrial pathway, ILC3s glycolysis plays a role in myocardial ischemia-reperfusion injury, affecting the survival and repair of cardiomyocytes. Regulation of the death receptor pathway: Glycolysis can also regulate the death receptor pathway of apoptosis signaling pathways by affecting the interaction between death receptors (such as Fas receptors) on the cell surface and their ligands. For example, the glycolysis state of ILC3s may affect the expression and activity of Fas ligands, thereby regulating the activation of Fas receptors and the activation of caspase-8, and further affecting the apoptosis process of cardiomyocytes. Regulation of apoptosis-related genes: ILC3s glycolysis can regulate apoptosis in cardiomyocytes by affecting the expression of Bcl-2 family genes and Caspase family genes. Metabolic products and metabolic sensing signals can regulate the transcription and translation of the above gene families' anti-apoptotic genes and pro-apoptotic genes, thereby affecting the expression and function of gene family proteins, and further regulating apoptosis in cardiomyocytes.

4. Potential Applications of ILC3s Glycolysis in MIRI Treatment

4.1. Key Enzymes, Metabolic Sensing Molecules, and Signal Pathways in ILC3s Glycolysis Pathway

4.1.1. Hexokinase, Phosphofructokinase, and Pyruvate Kinase

Key enzymes such as HK, PFK, and PK in the glycolysis pathway of ILC3s, metabolic sensing molecules (such as AMPK, mTOR), and signaling pathways (such as PI3K/Akt, JAK2/STAT3, Nrf2/HO-1) play important roles in MIRI and can be used as novel therapeutic targets in MIRI treatment. By regulating these targets, new therapeutic strategies can be developed to provide new ideas and methods for MIRI treatment. In ILC3s, the activity of HK and PFK directly affects the energy metabolism and function of cells. By regulating the activity of these enzymes, the metabolic state of ILC3s can be changed, thereby affecting their anti-inflammatory and protective functions in MIRI. Currently, inhibitors and activators of HK and PFK are being developed. For example, 2-deoxy-D-glucose (2-DG) is an HK inhibitor that inhibits glycolysis, reduces lactate production, and thereby reduces oxidative stress and inflammatory responses. Additionally, some small molecule compounds such as phosphofructokinase inhibitor (PFK-158) have been shown to activate PFK and enhance cellular energy metabolism. Currently, activators of PK such as pyruvate kinase activator (TEPP-46) are being studied. TEPP-46 activates PK, enhances cellular energy metabolism, and improves ischemia-reperfusion injury[86,87].

4.1.2. AMPK and mTOR

After activation, AMPK can promote glycolysis and fatty acid oxidation, enhancing cellular energy supply. The activity of mTOR is closely related to cell proliferation and metabolism. In ILC3s, the activity regulation of AMPK and mTOR can affect the metabolic state and function of cells, thereby exerting a protective role in MIRI. Currently, activators of AMPK such as AMP-activated protein kinase (AICAR) and Metformin have been widely studied[88,89]. AICAR activates AMPK, promotes cellular energy metabolism, reduces oxidative stress and inflammatory responses. Metformin activates AMPK, improves cellular metabolic state, and reduces myocardial ischemia-reperfusion injury. Additionally, mTOR inhibitors such as Rapamycin have been studied to regulate cell metabolism and function.

4.1.3. PI3K/Akt, JAK2/STAT3, and Nrf2/HO-1 Pathways

The PI3K/Akt signaling pathway plays an important role in cell survival and metabolic regulation, promoting cellular energy metabolism and anti-apoptotic functions by activating Akt. The JAK2/STAT3 signaling pathway plays a key role in cell proliferation and immune regulation. The Nrf2/HO-1 signaling pathway regulates the expression of antioxidant enzymes to reduce oxidative stress damage. Currently, activators of the PI3K/Akt pathway such as Insulin and insulin-like growth factor-1 (IGF-1) have been widely studied. Insulin activates the PI3K/Akt pathway, promotes cellular energy metabolism and survival. Additionally, JAK2 inhibitors such as Tofacitinib have been studied to regulate immune responses. Nrf2 activators such as Sulforaphane activate the Nrf2/HO-1 pathway, enhancing cellular antioxidant capacity.

4.2. Cardiomyocytes and Vasculature in ILC3s Glycolysis Pathway

4.2.1. Cardiomyocyte Proliferation

ILC3s glycolysis can promote the regeneration and repair of cardiomyocytes, enhancing the survival capacity of cardiomyocytes. In clinical treatment, activating the glycolysis pathway of ILC3s can provide more energy and biosynthetic precursors for cardiomyocytes, promote the proliferation and regeneration of cardiomyocytes, improve the prognosis after MIRI, reduce the area of myocardial infarction, and improve cardiac function. Cardiomyocyte proliferation can be detected by detecting the expression levels of proliferation markers such as nuclear protein (Ki-67) and proliferating cell nuclear antigen (PCNA) through immunohistochemistry or flow cytometry.

4.2.2. Angiogenesis

ILC3s glycolysis can promote angiogenesis by detecting microvascular density (MVD) or the expression levels of endothelial cell markers such as platelet endothelial cell adhesion molecule-1 (CD31) to assess the promoting effect of ILC3s-secreted VEGF and other factors on angiogenesis. VEGF is a key factor in promoting angiogenesis, which can stimulate myocardial angiogenesis, improve myocardial microcirculation, and thereby promote the regeneration and repair of cardiomyocytes. Recombinant VEGF and its analogs (such as VEGF-A, VEGF-C) have been widely studied for the treatment of myocardial ischemia-reperfusion injury[90]. Preclinical studies have shown that VEGF can significantly increase myocardial microvascular density and improve cardiac function.

4.3. Combined Applications of ILC3s Glycolysis in MIRI Treatment

4.3.1. Combination of ILC3s Glycolysis with Drug Therapy in MIRI Treatment

The regulation of ILC3s glycolysis can be used in combination with other treatments (such as drug therapy, ischemic preconditioning and postconditioning, stem cell therapy, etc.) to exert synergistic effects and improve treatment outcomes. Combination of ILC3s glycolysis with drug therapy in MIRI treatment: Drug therapy is usually used as a basic treatment method and can be performed before or simultaneously with the regulation of ILC3s glycolysis. For example, antioxidants such as N-acetylcysteine (NAC) [91]or anti-inflammatory drugs such as aspirin can be used before regulating ILC3s glycolysis to reduce initial inflammatory responses and oxidative stress, creating a more favorable environment for subsequent treatment. Antioxidants clear ROS to reduce oxidative stress damage. The regulation of ILC3s glycolysis activates the Nrf2/HO-1 signaling pathway to further enhance the expression of antioxidant enzymes, and the two work synergistically to more effectively protect cardiomyocytes. Aspirin inhibits the production of inflammatory mediators to reduce inflammatory responses. The regulation of ILC3s glycolysis secretes anti-inflammatory cytokines (such as IL-22) and inhibits pro-inflammatory cytokines (such as IL-1β) to further regulate immune responses.[39,92]

4.3.2. Combination of ILC3s Glycolysis with Ischemic Preconditioning and Postconditioning in MIRI Treatment

Combination of ILC3s glycolysis with ischemic preconditioning and postconditioning in MIRI treatment: Ischemic preconditioning (IPC) is usually performed before surgery or interventional treatment, while ischemic postconditioning (IPostC) is immediately implemented after blood flow is restored. The regulation of ILC3s glycolysis can be performed before or simultaneously with IPC or IPostC to enhance its protective effects. IPC activates endogenous protective mechanisms (such as the PI3K/Akt signaling pathway) to enhance the tolerance of cardiomyocytes. The regulation of ILC3s glycolysis activates similar signaling pathways to further enhance the energy metabolism and anti-apoptotic capacity of cardiomyocytes[93]. IPostC reduces oxidative stress and inflammatory responses during reperfusion to protect cardiomyocytes[94]. The regulation of ILC3s glycolysis secretes antioxidant enzymes and anti-inflammatory cytokines to further reduce oxidative stress and inflammatory damage.

4.3.3. Combination of ILC3s Glycolysis with Stem Cell Therapy in MIRI Treatment

Combination of ILC3s glycolysis with stem cell therapy in MIRI treatment: Stem cell therapy is usually performed as early as possible after MIRI to promote the regeneration and repair of cardiomyocytes. The regulation of ILC3s glycolysis can be performed before or simultaneously with stem cell transplantation to optimize the myocardial microenvironment and improve the survival rate and function of stem cells. Stem cells (such as mesenchymal stem cells) secrete growth factors (such as VEGF) to promote myocardial angiogenesis. The regulation of ILC3s glycolysis secretes similar factors to further enhance angiogenesis and cardiomyocyte repair capacity. The regulation of ILC3s glycolysis improves the energy metabolism of cardiomyocytes, providing a more favorable metabolic environment for stem cells, enhancing the survival rate and function of stem cells.

4.4. Clinical Detection and Individualized Adjustment Strategies for ILC3s Glycolysis in MIRI Treatment

4.4.1. Clinical Detection

The metabolic state of ILC3s glycolysis and ILC3s function may vary among different patients with MIRI. By evaluating the glycolysis characteristics and ILC3s status of patients, individualized treatment can be provided to develop more precise treatment plans. ILC3s function detection: Isolate ILC3s from peripheral blood or tissues, and detect surface markers such as CD45, CD127, CD3, CD117, etc. by flow cytometry. Cytokine secretion detection: Detect cytokines secreted by ILC3s such as IL-22, IL-17 using enzyme-linked immunosorbent assay (ELISA) or flow cytometry. Metabolic activity detection: Detect the glycolysis activity (such as glucose uptake, lactate production) and oxidative phosphorylation levels (such as ATP generation) of ILC3s to assess their metabolic state. In clinical practice, the functional state of ILC3s directly affects their protective role in MIRI. Abnormal ILC3s function may lead to exacerbated inflammatory responses or insufficient myocardial repair capacity. Gene detection and transcriptomics analysis: Analyze the gene expression profile of ILC3s by RNA sequencing (RNA-seq), focusing on genes related to glycolysis, inflammatory responses, and antioxidant functions. Changes in gene expression profiles in clinical practice may indicate metabolic reprogramming or functional dysfunction of ILC3s, providing a basis for targeted treatment.

4.4.2. Clinical Adjustment

Treatment plan adjustment strategies: High lactate levels: Indicates excessive glycolysis, which may worsen myocardial ischemic injury. Treatment strategies include using lactate clearers (such as lactate sodium) or drugs regulating the glycolysis pathway (such as 2-deoxy-D-glucose, 2-DG). Insulin resistance: Indicates metabolic disorders, which may affect the energy supply of ILC3s. Treatment strategies include using insulin sensitizers (such as metformin) or drugs regulating the AMPK signaling pathway. Insufficient IL-22 secretion: Indicates impaired anti-inflammatory and repair functions of ILC3s. Treatment strategies include using recombinant IL-22 protein or activating the glycolysis pathway of ILC3s (such as activating the PI3K/Akt signaling pathway). Excessive IL-17 secretion: Indicates excessive inflammatory response. Treatment strategies include using IL-17 inhibitors (such as secukinumab) or regulating the metabolic state of ILC3s to inhibit the secretion of pro-inflammatory cytokines. Low expression of Nrf2/HO-1 pathway: Indicates insufficient antioxidant capacity. Treatment strategies include using Nrf2 activators (such as sulforaphane) or regulating the expression of antioxidant enzymes. Abnormal PI3K/Akt pathway: Indicates impaired cell survival and metabolic regulation. Treatment strategies include using PI3K/Akt activators (such as insulin) or regulating metabolic sensing molecules (such as AMPK).

4.4.3. Treatment Plan Adjustment Strategies

Individualized adjustment of combined therapy: Drug combination: Adjust drug doses and combinations based on metabolic markers and ILC3s functional status. For example, for patients with metabolic disorders, combine the use of antioxidants and anti-inflammatory drugs. Ischemic preconditioning and postconditioning: For patients with normal ILC3s function, prioritize ischemic preconditioning or postconditioning to enhance the tolerance of cardiomyocytes. Stem cell therapy: For patients with impaired ILC3s function, combine stem cell therapy with metabolic regulation drugs to optimize the myocardial microenvironment.

4.4.4. Monitoring and Feedback

Treatment effect monitoring: Regularly detect metabolic markers and ILC3s functional status during treatment to assess treatment effects. For example, detect lactate levels and IL-22 secretion to determine whether glycolysis and anti-inflammatory functions have improved. Adverse reaction monitoring: Closely monitor possible adverse reactions in patients, such as drug side effects, immune responses, or metabolic disorders. Adjust the treatment plan if necessary. Individualized adjustment: Dynamically adjust the treatment plan according to the monitoring results to ensure the precision and effectiveness of the treatment.

5. Conclusion

MIRI poses a significant threat to patient health, and traditional treatment methods have many limitations. ILC3s and their glycolysis process have shown key roles and great potential in the field of MIRI. ILC3s, originating from common lymphoid progenitors and enriched in various tissues, have multiple functions such as anti-inflammation, immune balance regulation, promotion of cardiomyocyte regeneration, enhancement of cell survival, and activation of endogenous protective mechanisms, all of which rely on ILC3s glycolysis. Their glycolysis involves multiple aspects such as glucose uptake, various metabolic pathways, metabolic sensing molecule regulation, complex signal transduction, cytokine secretion regulation, metabolic product signaling, antioxidant enzyme and reactive oxygen species regulation, and apoptosis signaling pathway control, comprehensively affecting the pathological and physiological process of MIRI and thereby influencing the prognosis of MIRI. In terms of MIRI treatment, key enzymes, metabolic sensing molecules, and many signaling pathways in the glycolysis pathway of ILC3s are expected to become new therapeutic targets, opening the door to new treatment strategies; activating this glycolysis can help cardiomyocyte regeneration and repair, enhance survival capacity, and improve clinical prognosis; combining with other means such as drug therapy, ischemic preconditioning, and stem cell therapy can exert synergistic effects; at the same time, based on the individual differences in glycolysis characteristics and ILC3s functional status of patients, it is hoped to achieve precision and individualized treatment. However, current research still faces many challenges, including incomplete understanding of the specific mechanisms of ILC3s glycolysis, insufficient precision and effectiveness of regulatory means, and clinical transformation limited by patient individual differences and ethical considerations. In the future, it is necessary to strengthen the deep integration of basic and clinical research, overcome these barriers, fully explore the application value of ILC3s glycolysis in MIRI treatment, and open up more effective treatment paths for MIRI patients, improving patients' quality of life and prognosis.