Single-Nucleus Genomics of Liver Zonation: Insights and Clinical Implications

Abstract

Single-nucleus genomics has revolutionized our understanding of liver zonation by allowing high-resolution, cell-type-specific analysis of gene expression and epigenetic states within distinct hepatic zones. This review explores the latest advances in the application of single-nucleus sequencing technologies to map the molecular landscape of liver zonation, delineate spatial heterogeneity, and elucidate implications for liver physiology, disease susceptibility, and therapeutic innovation. Integrating recent evidence, this article discusses mechanisms driving zonal specialization, the impact on clinical features and management of liver diseases, and the potential of genomics-guided precision hepatology.

Introduction

Liver zonation refers to the spatial organization of distinct metabolic and functional profiles along the porto-central axis of the hepatic lobule. Classical studies using histology and in situ hybridization have described the metabolic compartmentalization of hepatocytes into periportal (zone 1), midzonal (zone 2), and pericentral (zone 3) regions. However, the intricate gene regulatory networks underlying zonation remained poorly understood until the advent of single-nucleus genomics. By enabling the isolation and profiling of individual nuclei from frozen liver tissue, single-nucleus RNA sequencing (snRNA-seq) and related modalities have overcome dissociation-induced artifacts and provided unprecedented resolution of zonal transcriptomic and epigenomic landscapes. Recent studies have leveraged these techniques to dissect the molecular architecture of liver zonation in health and disease, providing new insights with profound clinical relevance.

Epidemiology / Disease Burden

Liver diseases represent a significant global health burden, with over two million deaths annually attributed to cirrhosis, hepatitis, and hepatocellular carcinoma. The zonal heterogeneity of hepatocyte function and susceptibility underlies the pathogenesis of various liver disorders, including ischemia-reperfusion injury, drug-induced hepatotoxicity, nonalcoholic fatty liver disease (NAFLD), and viral hepatitis. Recent epidemiological studies have highlighted the role of zonally restricted gene expression patterns in determining disease localization and progression, emphasizing the need for precise molecular mapping to guide targeted interventions.

Pathophysiology

Liver zonation is orchestrated by gradients of oxygen, nutrients, hormones, and signaling molecules such as Wnt/β-catenin, Hedgehog, and Notch pathways. Periportal hepatocytes are enriched for gluconeogenesis, urea synthesis, and β-oxidation, whereas pericentral cells specialize in glycolysis, xenobiotic metabolism, and glutamine synthesis. Single-nucleus genomics has revealed that this metabolic compartmentalization is mirrored at the transcriptomic and chromatin accessibility levels, with distinct clusters of hepatocyte nuclei expressing zone-specific gene signatures. Furthermore, disease states such as steatohepatitis and fibrosis disrupt zonal gene expression patterns, contributing to pathological remodeling and functional impairment. The elucidation of zonal transcriptomic shifts in response to injury or metabolic stress provides a mechanistic framework for understanding disease progression and heterogeneity.

Risk Factors

Genetic predisposition, environmental exposures, metabolic syndrome, and chronic viral infections are established risk factors for liver diseases. Single-nucleus genomics has uncovered that the impact of these risk factors is often zone-specific: for example, pericentral hepatocytes are more susceptible to acetaminophen-induced toxicity due to high expression of cytochrome P450 enzymes, whereas periportal zones are preferentially affected in ischemic injury. Identification of zone-specific molecular vulnerabilities enhances risk stratification and informs the design of protective strategies tailored to individual patient profiles.

Clinical Features

Zonal heterogeneity manifests clinically in the pattern and severity of liver injury. For instance, centrilobular necrosis is a hallmark of drug toxicity, while periportal inflammation predominates in autoimmune hepatitis. Single-nucleus genomic profiling can detect early molecular alterations preceding histological changes, enabling the identification of subclinical disease and offering potential biomarkers for early diagnosis and prognosis. By mapping the spatial distribution of diseased and healthy hepatocytes, clinicians gain deeper insight into the clinical heterogeneity of liver disorders and can refine diagnostic and monitoring protocols accordingly.

Diagnosis

Traditional liver biopsies provide limited spatial and molecular resolution. Single-nucleus genomics overcomes these limitations by enabling high-throughput, unbiased profiling of thousands of nuclei from small tissue samples, including archived or frozen specimens. This technology allows for precise dissection of zonal gene expression and regulatory networks, facilitating the discovery of novel diagnostic markers and therapeutic targets. Integration with spatial transcriptomics further enhances localization accuracy, supporting the development of next-generation, zone-informed diagnostic assays for personalized hepatology.

Treatment & Management

Understanding the zonal context of liver function and disease paves the way for targeted therapeutic strategies. For example, interventions aimed at modulating Wnt/β-catenin signaling may preferentially restore pericentral hepatocyte function in certain forms of liver injury. Single-nucleus genomics can also identify zone-specific drug targets and predict off-target effects, improving the safety and efficacy of pharmacological agents. In the context of transplantation and regenerative medicine, mapping zonal gene expression guides the engineering of functional hepatocyte populations for cell therapy and bioartificial liver devices.

Recent Advances / Emerging Therapies

Recent advances in single-nucleus multi-omics, including simultaneous profiling of chromatin accessibility (snATAC-seq), DNA methylation, and proteomics, have deepened our understanding of the regulatory logic underpinning liver zonation. Emerging therapies, such as small-molecule modulators of zonal signaling pathways, gene-editing strategies, and zonally targeted drug delivery systems, are under active investigation. Preliminary studies demonstrate the feasibility of using single-nucleus genomics to monitor treatment response and identify resistance mechanisms at a spatially resolved level, heralding a new era of precision hepatology.

Guideline Recommendations

While single-nucleus genomics is not yet incorporated into routine clinical guidelines, leading hepatology societies recognize its transformative potential. Expert panels recommend the integration of single-nucleus and spatial transcriptomic data into research protocols for biomarker discovery and disease modeling. Future updates to clinical guidelines are anticipated as evidence accumulates regarding the utility of genomics-guided stratification and therapy in liver diseases.

Conclusion

The application of single-nucleus genomics has significantly advanced our understanding of liver zonation, revealing the cellular and molecular complexity underlying hepatic function and disease. By providing high-resolution maps of zonal gene expression and regulatory networks, this technology enables the identification of novel biomarkers, therapeutic targets, and mechanisms of disease heterogeneity. Continued integration of single-nucleus genomics with clinical practice promises to enhance diagnosis, risk stratification, and the development of precision therapies, ultimately improving outcomes for patients with liver disorders.