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Review Article
This review examines miRNAs in MASH pathogenesis, lipid metabolism, inflammation, and fibrosis, and their promise as biomarkers and therapeutics. Preclinical results are strong, but delivery, targeting, and standardization remain key hurdles. MiRNA-based diagnostics and therapeutics are precision tools for MASH management.
Metabolic-associated steatohepatitis (MASH) represents a growing global public health challenge. Its complex pathogenesis involves multiple pathological pathways, including lipid metabolism, inflammation, and fibrosis, yet effective specific diagnostic and therapeutic approaches remain elusive. MicroRNAs (miRNAs), as key post-transcriptional regulators, play an important role in the development and progression of MASH. This narrative review examines the molecular mechanisms by which miRNAs regulate lipid accumulation, inflammatory activation, hepatocyte injury, and fibrosis in MASH, while exploring their potential as non-invasive biomarkers for diagnosis and prognosis assessment. Additionally, the article focuses on analyzing the progress of preclinical research and the translational challenges of targeted therapeutic strategies based on miRNA mimics and antagonists, including delivery issues, off-target effects, reproducibility, and long-term safety. Despite encouraging preclinical evidence, major hurdles remain in clinical translation, including the lack of standardized protocols, efficient liver-specific delivery systems, and comprehensive safety data. Addressing these limitations may enable miRNA-based diagnostics and therapeutics to become precision tools for MASH management, though further validation through large-scale prospective studies is required.
The global prevalence of metabolic-associated fatty liver disease (MAFLD) and its inflammatory subtype, metabolic-associated steatohepatitis (MASH), is rapidly increasing, posing a significant public health issue1. As an advanced form of MAFLD, MASH serves as a major precursor to cirrhosis and hepatocellular carcinoma (HCC), and has become one of the primary indications for liver transplantation2,3. The pathological features of MASH are complex, encompassing hepatic steatosis, ballooning degeneration, lobular inflammation, and varying degrees of fibrosis. Its pathogenesis results from the interplay of genetic, metabolic, and environmental factors4. In recent years, epigenetic regulation, particularly the role of microRNA (miRNA), has attracted attention5. MiRNA is a class of non-coding RNA molecules approximately 22 nucleotides in length. By binding to the 3' untranslated regions of target messenger RNA (mRNA), they induce degradation or translational repression, thereby finely regulating extensive gene expression networks6,7. In MASH, specific miRNA expression profiles undergo significant alterations. These changes not only drive core pathological processes such as hepatic insulin resistance, lipid metabolism imbalance, activation of inflammatory signaling pathways, and activation of hepatic stellate cells, but also reflect the dynamic progression of the disease5,8. For instance, dysregulation of key miRNAs such as miR-122, miR-34a, and miR-21 has been demonstrated to be closely associated with hepatic lipid accumulation, inflammatory responses, and fibrosis progression9,10. Therefore, elucidating the role of miRNAs in MASH not only aids in understanding the essence of the disease but also paves the way for single-targeting, non-invasive diagnostic tools and novel therapies11. Compared with traditional protein biomarkers or single-target therapies, miRNA analysis offers unique advantages: miRNAs integrate upstream regulatory signals, can target multiple pathological pathways simultaneously, and are stable in circulation, making them attractive for both multi-panel diagnostics and network-based therapeutics. This paper systematically reviews the latest research advances in this field from four perspectives: pathogenesis, diagnostic value, therapeutic targets, and clinical translation prospects.
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Molecular networks of miRNA regulation in core pathogenesis mechanisms of MASH
Role of miRNAs in hepatic lipid metabolism and insulin resistance
In the pathogenesis of metabolic-associated steatohepatitis (MASH), microRNAs (miRNAs) form a complex molecular network by regulating hepatic lipid metabolism and insulin resistance. Dysregulation of hepatic lipid metabolism represents the initiating and central component of MASH, involving disturbances in lipid synthesis, oxidation, and transport12. Insulin resistance further exacerbates this metabolic imbalance by promoting the release of free fatty acids from adipose tissue into the liver, thereby driving hepatic steatosis13. Research indicates that specific miRNAs play pivotal roles in this process. For instance, miR-34a is upregulated in the livers of MASH patients. Its function has been shown to be associated with impaired thyroid hormone signaling pathways. It may exacerbate local hepatic resistance to thyroid hormones by targeting genes such as the thyroid hormone receptor β (THRβ), thereby affecting lipid metabolism10. Furthermore, miR-122, a liver-enriched miRNA, exhibits complex expression changes in the MASH context. Its levels correlate with disease severity and may influence hepatic lipid accumulation by regulating lipid-metabolism-related pathways14. The abnormal expression of these miRNAs not only directly modulates genes associated with lipid synthesis and oxidation but also forms an interconnected regulatory network by affecting insulin signaling pathways, collectively driving the onset and progression of MASH15. Gaining a deeper understanding of the regulatory mechanisms of these miRNAs may help elucidate the pathophysiological basis of MASH.
The specific regulation of hepatic lipid metabolism by miRNAs manifests at multiple levels. On one hand, they can target and regulate key transcription factors and enzymes involved in lipid synthesis. For example, increased hepatic expression of miR-33 correlates with MASLD progression; its deletion reduces lipid synthesis and promotes mitochondrial fatty acid oxidation, thereby alleviating hepatic lipid burden16. On the other hand, miRNAs regulate cholesterol homeostasis, and dysregulation of cholesterol metabolism is a key factor in the progression from MASLD to MASH17. Regarding insulin resistance, miRNAs influence hepatic insulin sensitivity by targeting key molecules in the insulin signaling pathway, such as insulin receptor substrates. Adipose tissue dysfunction and insulin resistance trigger lipid overflow into the liver, a process also regulated by miRNAs4. Furthermore, miRNAs mediate the lipotoxicity stress response. When free fatty acids overload, specific miRNAs (e.g., miR-155) are induced and upregulated. These miRNAs disrupt cholesterol homeostasis and potentially promote hepatocyte injury by targeting genes such as liver X receptor alpha (LXRα), thereby linking lipotoxicity to cellular damage15. Thus, miRNAs form a complex regulatory network in hepatic lipid metabolism and insulin resistance, whose dysregulation represents a core component in the pathogenesis of MASH.
miRNA-Driven inflammatory and apoptotic signaling pathways
The transition from simple steatosis to inflammation and fibrosis is a critical step in the progression of MASH. The role of miRNAs in driving inflammatory and cell death signaling pathways during this process has garnered attention. Lipotoxicity induced by hepatic lipid accumulation can lead to endoplasmic reticulum stress, oxidative stress, and mitochondrial dysfunction, subsequently triggering inflammatory responses and various forms of programmed cell death15. As crucial post-transcriptional regulators, miRNAs profoundly influence the inflammatory microenvironment and hepatocytes in MASH by modulating key inflammatory molecules and cell death effector proteins. For instance, miR-21 exhibits sustained upregulation in MASH and MASH-associated hepatocellular carcinoma (HCC), and its overexpression promotes lipid metabolic alterations and drives HCC development18. MiR-21 expression is upregulated during the progression of MASH-associated cirrhosis and HCC18. In animal models, hepatocyte-specific overexpression of miR-21 is sufficient to drive hepatic overgrowth and increase HCC incidence, while miR-21 inhibition attenuates β-catenin-driven hepatomegaly, indicating miR-21 may regulate fibrosis progression and carcinogenesis18. The dysregulation of these miRNAs collectively forms a network that drives hepatic inflammation and injury.
MiRNAs activate classical inflammatory signaling pathways through multiple mechanisms. They can directly target proteins that negatively regulate inflammatory signaling, thereby lifting inhibition and amplifying the inflammatory response. For example, miR-155 packaged within small extracellular vesicles derived from MASH adipose tissue macrophages, rich in pro-fibrotic miR-155 and miR-34a, induces hepatic stellate cell activation, exacerbating liver fibrosis in obese mice19. This suggests miR-155 may enhance proinflammatory signaling pathways like JAK-STAT by targeting genes such as cytokine-signaling inhibitor 1 (SOCS1). Concurrently, miRNAs actively regulate pyroptosis and apoptosis. Impaired endoplasmic reticulum stress sensors affect the degradation of specific miRNAs, leading to their accumulation in the liver. As discussed above, miR-34a also promotes inflammation by downregulating peroxisome proliferator-activated receptor alpha (PPARα), linking metabolic dysfunction to inflammatory activation. MiR-155 and miR21 can also subsequently downregulate key regulators involved in fatty acid oxidation and anti-inflammatory responses, thereby promoting inflammation20. Furthermore, miRNAs play a role in linking innate and adaptive immunity. The polarization and function of immune cells in the liver, such as macrophages (Kupffer cells) and lymphocytes, are regulated by specific miRNAs. For instance, adipose tissue macrophages exhibit proinflammatory and lipid-related phenotypes in MASH, and the miRNA cargo (e.g., miR-155) secreted in their extracellular vesicles exhibits pro-fibrotic effects, highlighting the mechanistic importance of extrahepatic signaling in MASH19. Therefore, targeting these miRNAs that drive inflammation and cell death may offer novel therapeutic strategies for MASH. Figure 1 illustrates the key roles of miRNAs in hepatic lipid metabolism, insulin resistance, inflammation, cell death, and fibrosis, with upregulated miRNAs shown in red and downregulated miRNAs in green.
miRNAs as biomarkers for non-invasive diagnosis and prognostic assessment of MASH
Circulating miRNAs for MASH screening and differential diagnosis
Circulating miRNAs, due to their stable presence in blood and ease of acquisition, have emerged as promising biomarkers for non-invasive diagnosis of MASH. Studies indicate that specific circulating miRNA profiles can effectively distinguish simple fatty lesions from MASH. For instance, serum expression levels of molecules such as miR-122-5p, miR-21-5p, and miR-34a-5p are altered in MASH patients9. A study employing high-throughput sequencing analysis revealed that miR-122-5p and miR-375-3p were significantly upregulated in exosomes from "high-risk MASH" patients and correlated with disease severity8. These miRNA alterations are closely associated with hepatocyte injury and inflammatory responses, potentially offering superior diagnostic performance compared to traditional liver enzyme markers. Furthermore, circulating miRNAs offer significant stability advantages. Typically present in exosomes or bound to the Argonaute 2(AGO2) protein, they resist degradation by RNases, ensuring reliability in standardized blood draws and repeated clinical testing21. This stability positions circulating miRNA-based detection panels as promising tools for screening and differentiating MASH in clinical practice.
Circulating miRNA expression levels not only aid disease classification but also dynamically reflect MASH activity. Studies reveal that circulating miR-155 levels positively correlate with hepatic inflammation activity scores19. In animal models, exosomes derived from adipose tissue macrophages are enriched with miR-155 and miR-34a, activating hepatic stellate cells and promoting fibrosis, suggesting circulating miR-155 serves as a non-invasive monitor of liver inflammation19. Conversely, miR-34a-5p is upregulated in the livers of MASH patients and positively correlates with clinical-pathological parameters. Its overexpression targets and inhibits genes such as the THR β, potentially mediating acquired resistance to thyroid hormones in the liver and thereby contributing to disease progression10. Therefore, monitoring the dynamic changes of these miRNAs can provide crucial information for assessing the severity of hepatic inflammation and fibrosis, enabling non-invasive monitoring of disease progression.
Circulating miRNAs also offer exceptional stability and clinical accessibility as biomarkers (Table 1). They primarily exist in the circulatory system as exosomes or bound to proteins like (AGO2), a structure that confers high resistance to RNA degradation enzymes prevalent in plasma22. This inherent stability ensures miRNA integrity during sample collection, storage, and transport, making them suitable for repeated clinical testing and long-term monitoring. Serum or plasma samples can be standardized through simple venous blood collection, making circulating miRNA-based detection non-invasive, relatively low-cost, and easily scalable for clinical implementation9. With ongoing advancements in detection technologies, such as ultra-sensitive imaging based on nanoplatforms, future prospects even include simultaneous visual detection of key molecules like miR-122 and miR-21, providing powerful tools for early diagnosis and pathological clarification23.
miRNA Profiles predict fibrosis progression and liver disease outcomes
Specific miRNA expression profiles are correlated with MASH fibrosis staging, serving as important biomarkers for predicting disease progression and liver-related outcomes. Studies have revealed that certain miRNAs exhibit specific expression patterns in advanced fibrosis stages. Furthermore, miR-34a carried by exosomes from adipose tissue macrophages has been shown to downregulate PPAR-γ expression, thereby promoting hepatic stellate cell activation and fibrosis19. These findings suggest that molecules such as miR-21 and miR-34a may serve as specific markers for advanced fibrosis, with their expression levels paralleling the degree of hepatic stellate cell activation.
Dynamic changes in circulating miRNAs not only reflect current disease status but also predict treatment response and long-term prognosis. In MASH patients undergoing intervention, pre- and post-treatment alterations in specific miRNAs correlate with histological improvement. For example, miR-34a-5p upregulation positively correlates with MASH severity, making targeted inhibition of miR-34a a promising therapeutic strategy10. Clinical data indicate that elevated baseline miR-21 levels are associated with accelerated fibrosis progression risk and increased hepatocellular carcinoma incidence9,18. Regarding prognostic assessment, serum miR-4651 levels are significantly reduced in MASH or cirrhosis patients, demonstrating strong discriminatory ability between "complex" MASH (i.e., MASH or cirrhosis) and simple steatosis. Its predictive value can be further enhanced by combining other parameters, such as FibroScan24. This evidence suggests that monitoring the expression trends of key miRNAs helps identify high-risk patients and predict liver disease-related outcomes (Table 2).
To achieve more precise risk stratification and personalized management for MASH patients, integrating miRNA biomarkers with other omics data and clinical parameters to construct multi-omics diagnostic models represents a future direction. Studies indicate that combining circulating miRNAs with clinical indicators (e.g., FIB-4 index) or protein biomarkers (e.g., CK-18) significantly improves diagnostic and predictive accuracy9. Research also reveals that circZBTB46 acts as a competitive endogenous RNA (ceRNA) to sequester miR-326, thereby releasing its inhibition on fibroblast growth factor 1 (FGF1). This circRNA-miRNA-mRNA regulatory axis offers new insights into the molecular mechanisms of MASLD and into the development of novel biomarkers25. By integrating genomic, epigenetic (e.g., DNA methylation), and metabolomic features, more robust predictive models can be developed to advance precision medicine practices for MASH12.
miRNA-Targeting MASH therapeutic strategies: From basic to preclinical research
Replacement therapy strategy using miRNA mimics
In the pathogenesis of MASH, downregulation of multiple protective miRNAs exacerbates hepatic lipid accumulation, inflammation, and fibrosis. Therefore, exogenous supplementation of these miRNA mimics to restore their physiological functions represents a therapeutic strategy. For instance, miR-122 is highly expressed in the liver, and its downregulation is closely associated with MASH progression14. In animal models, delivery of miR-122 mimics via lipid nanoparticles effectively modulates the expression of genes related to hepatic lipid metabolism and alleviates hepatic steatosis14. Furthermore, miR-34a is significantly upregulated in the livers of MASH patients. Its overexpression inhibits the expression of key metabolic regulators such as THRβ and deiodinase 1 (DIO1), thereby exacerbating thyroid hormone resistance and metabolic dysfunction in the liver10. Therefore, antagonistic strategies targeting miR-34a are equally important, while supplementation with other protective miRNAs, such as miR-320, demonstrates therapeutic potential. Studies indicate that miR-320 downregulation in hepatocytes accelerates MASH progression, whereas its restoration via. adeno-associated virus (AAV) vectors significantly improves diet-induced MASH model steatosis and fibrosis by upregulating FGF1 through RFX1 inhibition and activating the AMPK pathway26. Collectively, these studies suggest the feasibility of correcting gene expression network imbalances by delivering specific miRNA mimics to counteract core pathological mechanisms of MASH.
However, successfully translating miRNA mimics into clinical therapies faces multiple challenges. The primary obstacles are their stability in vivo and targeted delivery issues. Unmodified synthetic miRNAs are rapidly degraded by RNases in the bloodstream and lack tissue specificity, potentially leading to systemic off-target effects27. To enhance stability and liver targeting, novel delivery systems are under active development. For instance, encapsulating miRNA mimics within lipid nanoparticles or cationic polymers (e.g., polyethyleneimine nanoparticles (PEI-NPs) protects them from degradation while improving hepatic uptake efficiency through enhanced permeation and retention effects or active targeting ligands (e.g., GalNAc, a sugar cluster that binds with high affinity to the desialylated glycoprotein receptor on hepatocyte surfaces)27. Beyond chemical modifications and carrier systems, utilizing engineered extracellular vesicles (EVs) as natural carriers for delivering miRNA mimics also shows tremendous potential. Mesenchymal stem cell-derived EVs have been shown to alleviate hepatic lipid accumulation and injury, with their miRNA cargo likely playing a key role21. These advanced delivery technologies aim to achieve efficient, specific enrichment of analogs within hepatocytes, thereby enhancing therapeutic efficacy while minimizing potential off-target effects on extrahepatic tissues, which may facilitate future clinical translation of miRNA replacement therapies. Figure 2 summarizes the current preclinical strategies for targeting miRNAs in MASH, including miRNA mimics (e.g., miR-320) delivered via .lipid nanoparticles, AAV, or GalNAc conjugation, and miRNA antagonists (e.g., anti-miR‑34a, anti-miR‑21) using chemically modified antisense oligonucleotides.
Suppressive therapeutic strategy with miRNA antagonists (Antagomirs/ASOs)
In contrast to strategies supplementing protective miRNAs, inhibiting pathogenic miRNAs abnormally overexpressed in MASH and driving disease progression represents another therapeutic pathway. These miRNA antagonists are typically chemically modified antisense oligonucleotides (ASOs) that bind and silence target miRNAs via. base-pairing. Among them, miR-34a and miR-21 are two highly implicated pathogenic factors in MASH. By targeting genes such as THRβ and DIO1, it impairs thyroid hormone signaling in the liver and promotes metabolic dysfunction10. Targeting miR-21, which drives both inflammation and fibrosis (section 1.2), has shown preclinical efficacy. In preclinical studies, silencing these miRNAs using chemically modified antisense oligonucleotides such as lock nucleic acids (LNAs) has demonstrated significant effects in MASH mouse models, including improvements in hepatic steatosis, inflammation, and fibrosis19. For example, small extracellular vesicles from MASH adipose tissue macrophages are enriched with miR-34a and miR-155, which activate hepatic stellate cells and promote fibrosis; whereas antagomirs targeting miR-34a and miR-155 block this pro-fibrotic effect19. These studies provide a basis for developing antagonist therapies targeting single or multiple pathogenic miRNAs.
In recent years, significant progress has been made in pharmacokinetic engineering and safety evaluation of miRNA antagonists. Unmodified oligonucleotides are readily degraded by nucleases in vivo. and undergo rapid renal clearance. Chemical modifications, such as introducing LNA, 2'-O-methoxyethyl (2'-MOE), or phosphorothioate groups, can significantly enhance binding affinity to target miRNAs, improve resistance to enzymatic degradation, and prolong plasma and tissue half-lives28. These improvements enable sustained therapeutic effects at lower doses and reduced administration frequencies. Regarding safety, several candidate drugs have entered early clinical development phases and have demonstrated good tolerability. For instance, while clinical data for RG-125 are not directly referenced in the literature, trends in the field indicate that rational chemical design and liver-targeted delivery (e.g., GalNAc conjugation) can optimize drug distribution properties. This allows for preferential accumulation in the liver, thereby reducing systemic exposure and potential off-target toxicity28. A study developed a tetrahedral framework nucleic acid (TDN)-based nanosystem for delivering miR-34a inhibitors. This system not only enhanced inhibitor stability and cellular uptake efficiency but also effectively alleviated hepatic steatosis, inflammation, and fibrosis in MASH mouse models without significant reported toxicity, demonstrating the potential of novel delivery systems to improve therapeutic indices28. These advances signal the transition of miRNA antagonists from laboratory research to clinical validation.
Given the complexity of MASH pathogenesis, involving multiple pathways such as lipid metabolism, inflammation, and fibrosis, monotherapy targeting a single pathway may yield limited efficacy. Therefore, combining miRNA-targeted therapies with existing or emerging drugs to generate synergistic or additive effects holds significant promise. For instance, hormonal agents such as glucagon-like peptide-1 receptor agonists (GLP-1RAs) and THRβ agonists (e.g., rimedotiroptide) have demonstrated efficacy in improving metabolic parameters and hepatic histology in MASH treatment29. Antagonists targeting miR-34a or miR-21 can respectively correct thyroid hormone resistance and suppress proinflammatory/pro-fibrotic signaling. When combined with GLP-1RAs or THRβ agonists, they may synergistically improve insulin sensitivity, reduce hepatic lipid accumulation, and alleviate inflammation at multiple levels. This approach may achieve superior therapeutic outcomes and potentially allow dose reductions of individual drugs to minimize side effects10,18. Additionally, therapies targeting gut microbiota-host interactions (e.g., probiotic supplementation or specific metabolites) are also recognized for modulating relevant miRNA expression profiles5. Future research must delve into the synergistic mechanisms, optimal combinations, and dosing sequences of these combined approaches. By acting on different nodes within the disease network, they could provide more effective and personalized comprehensive treatment strategies for MASH patients.
Challenges in miRNA research and prospects for clinical translation
Current Research Limitations and Technical Challenges
Despite significant advances in understanding miRNA roles in MASH, clinical translation faces multiple hurdles. First, species differences and model limitations pose obstacles. Many key miRNA functional discoveries originate from animal models such as mice. However, significant differences exist in miRNA expression profiles and regulatory networks across species, limiting direct translation from animal models to human disease30. For instance, specific miRNA expression patterns observed in human MASH patients may not be fully reproducible in existing mouse models. Furthermore, existing in vitro. cellular models, such as single-cell cultures of hepatocytes or hepatic stellate cells, struggle to mimic the complex multicellular microenvironment involved in MASH pathogenesis. This includes the dynamic interactions among hepatocytes, Kupffer cells, hepatic stellate cells, and immune cells, hindering a deeper understanding of miRNA mediation within disease networks31. Additionally, the complexity and redundancy of miRNA functions make precise elucidation of their pathological roles exceptionally challenging. A single miRNA can target hundreds of mRNAs, while a single gene may be regulated by multiple miRNAs, forming a highly interwoven regulatory network32. This network characteristic introduces uncertainty when predicting the biological consequences of intervening in specific miRNAs. Further complicating matters, certain miRNAs may exert diametrically opposed effects at different disease stages. For instance, miR-122, a miRNA enriched in the liver, exhibits inconsistent reports across studies regarding its expression changes in relation to MASH progression, highlighting its context-dependent functionality14. Finally, standardization and validation botTlenecks severely hinder the clinical application of circulating miRNAs as biomarkers. Currently, a lack of globally unified standardized procedures, from blood sample collection and RNA extraction to miRNA quantification methods (e.g., qRT-PCR), prevents the development of a standardized miRNA-based diagnostic test. sequencing), results in poor comparability of results across research institutions9. To advance promising miRNA biomarkers (e.g., miR-122, miR-34a, miR-21) into clinical practice, rigorous validation through large-scale, prospective, multicenter cohort studies is essential to establish reliable cutoff values and clinical utility for diagnosing MASH or differentiating disease severity24. Given the wide variability in preanalytical, analytical, and postanalytical factors across studies, establishing standardized protocols is essential for clinical translation of miRNA‑based diagnostics and therapeutics. Practical recommendations to address these reproducibility challenges are summarized in Table 3.
Overexpression of miR-149-5p in human liver organs successfully simulated and promoted the development of lipid accumulation, inflammation, and fibrosis33. This result is not only mutually confirmed with the research findings of the mouse model and hepatocellular carcinoma cell line in vivo., but more importantly, it proves that human liver organs can reproduce the complex multi-cell interaction and pathological features (such as inflammation and fibrosis) in MASLD, which goes beyond the limitations of traditional two-dimensional cell culture. Therefore, human liver organs provide a powerful tool for in-depth study of disease mechanisms and screening potential therapies in human-related systems.
The delivery of miRNA therapeutic drugs faces multiple obstacles, including enzymatic degradation, rapid clearance, endosomal escape, and off-target effects. The off-target effect mainly comes from the non-specific binding of miRNA sequences and the non-selective distribution of the delivery system34. Optimizing endosome escape by ionizing/fusing chemical modification (such as pH-sensitive lipids) can reduce the premature release and misplacement of intracellular miRNA 1. However, the key obstacle to repeatability is the lack of a standardized evaluation system, which makes it difficult to compare the results between different studies. For example, the parameters such as particle size, polydispersity, and encapsulation efficiency of lipid nanoparticles need to be measured by a unified method. Evaluation and regulatory challenges for the long-term safety of miRNA therapeutic drugs: immunogenicity (e.g., TLR activation) and chronic toxicity (e.g., liver injury) are the main risks for clinical translation. In preclinical studies, animal models should be used to evaluate organ toxicity under long-term exposure, and functionalized lipid nanoparticles (such as degradable lipids) can reduce cumulative toxicity34.
Future directions and translational medicine pathways
To address these challenges, future research should focus on several translational pathways to advance miRNAs from basic research to clinical application. A primary direction involves developing organ- and cell-type-specific delivery systems. Modifying therapeutic miRNA mimics or antagonists with nanotechnology or specific ligands (e.g., GalNAc targeting hepatocytes) enables precise drug delivery to target cell types such as hepatocytes, activated hepatic stellate cells, or proinflammatory Kupffer cells, thereby enhancing efficacy while minimizing systemic toxicity27. For instance, delivery systems based on scaffolded nucleic acids or nanoparticles have been explored to protect miRNAs and enhance cellular uptake, offering novel tools for targeted therapy28. Furthermore, the exploration of miRNA-based combination therapies holds great promise for personalized medicine. Given the high heterogeneity of MASH, future approaches could involve disease subtyping based on patients' "miRNA fingerprint" expression profiles. This would guide the selection of the most suitable targeted miRNA therapeutics or their combination with existing therapies (e.g., GLP-1 receptor agonists, FXR agonists) for personalized treatment11. For instance, patients overexpressing pro-fibrotic miR-34a or miR-21 may benefit from corresponding antagonists10,18. Third, advancing closed-loop research from biomarkers to therapeutic targets is crucial for achieving "diagnostic-therapeutic integration."Ideally, diagnostic miRNA markers should be directly linked to corresponding therapeutic interventions. For instance, MASH patients with elevated levels of specific pathogenic miRNAs (e.g., miR-21 or miR-33) in circulating or liver tissue could receive targeted miRNA antagonists, creating a closed-loop model where diagnosis guides treatment16,18. Finally, strengthening regulatory science and clinical trial design is paramount. Clear regulatory pathways for miRNA-based therapeutics and diagnostic products must be established. Clinical trial designs must incorporate reliable miRNA pharmacodynamic and pharmacodynamic biomarkers while closely monitoring long-term safety and potential off-target effects to ensure these novel therapies safely and effectively benefit patients11. By overcoming these challenges through multidisciplinary collaboration, miRNAs may become valuable tools in the precision diagnosis and targeted treatment of MASH.
Prospect
Looking ahead, research in this field requires coordinated advancement across multiple fronts. In basic research, it is essential to deeply analyze species differences in miRNA function between humans and model animals and elucidate the pleiotropic effects of individual miRNAs within complex regulatory networks to accurately predict intervention outcomes.
In translational applications, the immediate priority is developing more efficient and specific liver-targeted delivery technologies. Concurrently, exploring combination strategies between miRNA therapies and existing drugs (such as GLP-1 receptor agonists and FXR agonists) is crucial to achieve synergistic effects.
Ultimately, rigorously designed, large-scale prospective clinical studies to validate diagnostic value and therapeutic benefits are essential to advance miRNAs from promising biomolecules to routine tools in MASH clinical management. This holds promise for delivering revolutionary, precise non-invasive diagnostic tools and novel therapeutic options to the growing global cohort of MASH patients.
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In summary, miRNAs play important roles in MASH pathogenesis by fine-tuning core gene networks involved in lipid metabolism, inflammation, cell death, and fibrosis. Their dynamic expression profiles reflect liver pathology and offer molecular insights into disease heterogeneity.
From a clinical perspective, circulating miRNAs hold promise as non-invasive biomarkers. Their correlation with hepatic pathology supports potential applications in non-invasive diagnosis and stratification of disease ...
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This work was supported by grants from the Qingdao Key Health Discipline Development Program, Key Specialty for Integrated Traditional Chinese and Western Medicine Hepatology (Grant No. 20240357), and the Qingdao Key Health Discipline Development Program, Peak Discipline (Grant No. 20240306).
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