Liver Disease and Risk of Hepatocellular Carcinoma in Children With Mutations in TALDO1

Gluconolactone restores immune regulation and alleviates skin inflammation in lupus-prone mice and in patients with cutaneous lupus

Systemic lupus erythematosus (SLE) is characterized by dysfunctional regulatory T cells (Tregs). We previously showed that protein phosphatase 2A (PP2A) plays a critical role in maintaining the suppressive function of Tregs. Here, we analyzed phosphoproteomics and metabolomics data from PP2A-wild type and PP2A-deficient Tregs and demonstrated that PP2A regulates Treg function through the pentose phosphate pathway (PPP). Furthermore, we proved that the PPP metabolite gluconolactone (GDL) enhances in vitro induced (i)Treg differentiation and function by promoting forkhead box protein 3 and phosphorylated signal transducer and activator of transcription 5 expression and inhibits T helper 17 (TH17) differentiation in murine cells. In short-term imiquimod-induced autoimmunity in mice, treatment with GDL alleviates inflammation by inhibiting TH17 cells. GDL promotes Tregs function and alleviates skin lesions in MRL.lpr lupus-prone mice in vivo. It also promotes Tregs differentiation and function in ex vivo experiments using cells from patients with SLE. Last, in patients suffering from cutaneous lupus erythematosus, topical application of a GDL-containing cream controlled skin inflammation and improved the clinical and histologic appearance of the skin lesions within 2 weeks. Together, we have identified GDL as a PPP metabolite and showed mechanistically that it restores immune regulation in vitro and in vivo by inducing Treg suppressive function and inhibiting TH17 cells. GDL should be considered as a treatment approach for inflammatory and autoimmune diseases.

Establishment of a Lactylation-Related Gene Signature for Hepatocellular Carcinoma Applying Bulk and Single-Cell RNA Sequencing Analysis

Background: Lactylation is closely involved in cancer progression, but its role in hepatocellular carcinoma (HCC) is unclear. The present work set out to develop a lactylation-related gene (LRG) signature for HCC. Methods: The lactylation score of tumor and normal groups was calculated using the gene set variation analysis (GSVA) package. The single-cell RNA sequencing (scRNA-seq) analysis of HCC was performed in the "Seurat" package. Prognostic LRGs were selected by performing univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses to develop and validate a Riskscore model. Functional enrichment analysis was conducted by gene set enrichment analysis (GSEA) using the "clusterProfiler" package. Genomic characteristics between different risk groups were compared, and tumor mutational burden (TMB) was calculated by the "Maftools" package. Immune cell infiltration was assessed by algorithms of cell-type identification by estimating relative subsets of RNA transcript (CIBERSORT), microenvironment cell populations-counter (MCP-counter), estimating the proportions of immune and cancer cells (EPIC), tumor immune estimation resource (TIMER), and single-sample gene set enrichment analysis (ssGSEA). Immunotherapy response was predicted by the tumor immune dysfunction and exclusion (TIDE) algorithm. Drug sensitivity was analyzed using the "pRRophetic" package. A nomogram was established using the "rms" package. The expressions of the prognostic LRGs in HCC cells were verified by in vitro test, and cell counting kit-8 (CCK-8), wound healing, and transwell assays were carried out to measure the viability, migration, and invasion of HCC cells. Results: The lactylation score, which was higher in the tumor group than in the normal group, has been confirmed as an independent factor for the prognostic evaluation in HCC. Six prognostic LRGs, including two protective genes (FTCD and APCS) and four risk genes (LGALS3, C1orf43, TALDO1, and CCT5), were identified to develop a Riskscore model with a strong prognostic prediction performance in HCC. The scRNA-seq analysis revealed that LGALS3 was largely expressed in myeloid cells, while APCS, FTCD, TALDO1, CCT5, and C1orf43 were mainly expressed in hepatocytes. The high-risk group was primarily enriched in the pathways involved in tumor occurrence and development, with higher T cell infiltration. Moreover, the high-risk group was found to be less responsive to immunotherapy but was more sensitive to chemotherapeutic drugs. By integrating Riskscore and clinical features, a nomogram with a high predictive accuracy was developed. Additionally, C1orf43, CCT5, TALDO1, and LGALS3 were highly expressed in HCC cells. Silencing CCT5 inhibited the viability, migration, and invasion of HCC cells. Conclusion: The present work developed a novel LRG gene signature that could be considered a promising therapeutic target and biomarker for HCC.

ALDOB/KAT2A interactions epigenetically modulate TGF-β expression and T cell functions in hepatocellular carcinogenesis

BACKGROUND AND AIMS

Cross talk between tumor cells and immune cells enables tumor cells to escape immune surveillance and dictate responses to immunotherapy. Previous studies have identified that downregulation of the glycolytic enzyme fructose-1,6-bisphosphate aldolase B (ALDOB) in tumor cells orchestrated metabolic programming to favor HCC. However, it remains elusive whether and how ALDOB expression in tumor cells affects the tumor microenvironment in HCC.

APPROACH AND RESULTS

We found that ALDOB downregulation was negatively correlated with CD8 + T cell infiltration in human HCC tumor tissues but in a state of exhaustion. Similar observations were made in mice with liver-specific ALDOB knockout or in subcutaneous tumor models with ALDOB knockdown. Moreover, ALDOB deficiency in tumor cells upregulates TGF-β expression, thereby increasing the number of Treg cells and impairing the activity of CD8 + T cells. Consistently, a combination of low ALDOB and high TGF-β expression exhibited the worst overall survival for patients with HCC. More importantly, the simultaneous blocking of TGF-β and programmed cell death (PD) 1 with antibodies additively inhibited tumorigenesis induced by ALDOB deficiency in mice. Further mechanistic experiments demonstrated that ALDOB enters the nucleus and interacts with lysine acetyltransferase 2A, leading to inhibition of H3K9 acetylation and thereby suppressing TGFB1 transcription. Consistently, inhibition of lysine acetyltransferase 2A activity by small molecule inhibitors suppressed TGF-β and HCC.

CONCLUSIONS

Our study has revealed a novel mechanism by which a metabolic enzyme in tumor cells epigenetically modulates TGF-β signaling, thereby enabling cancer cells to evade immune surveillance and affect their response to immunotherapy.

GREGoR: Accelerating Genomics for Rare Diseases

Rare diseases are collectively common, affecting approximately one in twenty individuals worldwide. In recent years, rapid progress has been made in rare disease diagnostics due to advances in DNA sequencing, development of new computational and experimental approaches to prioritize genes and genetic variants, and increased global exchange of clinical and genetic data. However, more than half of individuals suspected to have a rare disease lack a genetic diagnosis. The Genomics Research to Elucidate the Genetics of Rare Diseases (GREGoR) Consortium was initiated to study thousands of challenging rare disease cases and families and apply, standardize, and evaluate emerging genomics technologies and analytics to accelerate their adoption in clinical practice. Further, all data generated, currently representing ~7500 individuals from ~3000 families, is rapidly made available to researchers worldwide via the Genomic Data Science Analysis, Visualization, and Informatics Lab-space (AnVIL) to catalyze global efforts to develop approaches for genetic diagnoses in rare diseases (https://gregorconsortium.org/data). The majority of these families have undergone prior clinical genetic testing but remained unsolved, with most being exome-negative. Here, we describe the collaborative research framework, datasets, and discoveries comprising GREGoR that will provide foundational resources and substrates for the future of rare disease genomics.

What's new in pediatric genetic cholestatic liver disease: advances in etiology, diagnostics and therapeutic approaches

PURPOSE OF REVIEW

To highlight recent advances in pediatric cholestatic liver disease, including promising novel prognostic markers and new therapies.

FINDINGS

Additional genetic variants associated with the progressive familial intrahepatic cholestasis (PFIC) phenotype and new genetic cholangiopathies, with an emerging role of ciliopathy genes, are increasingly being identified. Genotype severity predicts outcomes in bile salt export pump (BSEP) deficiency, and post-biliary diversion serum bile acid levels significantly affect native liver survival in BSEP and progressive familial intrahepatic cholestasis type 1 (FIC1 deficiency) patients. Heterozygous variants in the MDR3 gene have been associated with various cholestatic liver disease phenotypes in adults. Ileal bile acid transporter (IBAT) inhibitors, approved for pruritus in PFIC and Alagille Syndrome (ALGS), have been associated with improved long-term quality of life and event-free survival.

SUMMARY

Next-generation sequencing (NGS) technologies have revolutionized diagnostic approaches, while discovery of new intracellular signaling pathways show promise in identifying therapeutic targets and personalized strategies. Bile acids may play a significant role in hepatic damage progression, suggesting their monitoring could guide cholestatic liver disease management. IBAT inhibitors should be incorporated early into routine management algorithms for pruritus. Data are emerging as to whether IBAT inhibitors are impacting disease biology and modifying the natural history of the cholestasis.

Genetic aetiologies of acute liver failure

Acute liver failure (ALF) is a rare, rapidly evolving, clinical syndrome with devastating consequences where definitive treatment is by emergency liver transplantation. Establishing a diagnosis can be challenging and, historically, the cause of ALF was unidentified in up to half of children. However, recent technological and clinical advances in genomic medicine have led to an increasing proportion being diagnosed with monogenic aetiologies of ALF. The conditions encountered include a diverse group of inherited metabolic disorders each with prognostic and treatment implications. Often these disorders are clinically indistinguishable and may even mimic disorders of immune regulation or red cell disorders. Rapid genomic sequencing for children with ALF is, therefore, a key component in the diagnostic work up today. This review focuses on the monogenic aetiologies of ALF.

mTOR-dependent loss of PON1 secretion and antiphospholipid autoantibody production underlie autoimmunity-mediated cirrhosis in transaldolase deficiency

Transaldolase deficiency predisposes to chronic liver disease progressing from cirrhosis to hepatocellular carcinoma (HCC). Transition from cirrhosis to hepatocarcinogenesis depends on mitochondrial oxidative stress, as controlled by cytosolic aldose metabolism through the pentose phosphate pathway (PPP). Progression to HCC is critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Although AR inactivation blocked susceptibility to hepatocarcinogenesis, it enhanced growth restriction, carbon trapping in the non-oxidative branch of the PPP and failed to reverse the depletion of glucose 6-phosphate (G6P) and liver cirrhosis. Here, we show that inactivation of the TAL-AR axis results in metabolic stress characterized by reduced mitophagy, enhanced overall autophagy, activation of the mechanistic target of rapamycin (mTOR), diminished glycosylation and secretion of paraoxonase 1 (PON1), production of antiphospholipid autoantibodies (aPL), loss of CD161+ NK cells, and expansion of CD38+ Ito cells, which are responsive to treatment with rapamycin in vivo. The present study thus identifies glycosylation and secretion of PON1 and aPL production as mTOR-dependent regulatory checkpoints of autoimmunity underlying liver cirrhosis in TAL deficiency.

Role of Alpha-Fetoprotein (AFP) in Diagnosing Childhood Cancers and Genetic-Related Chronic Diseases

Alpha-fetoprotein (AFP) is a protein commonly found during fetal development, but its role extends beyond birth. Throughout the first year of life, AFP levels can remain high, which can potentially mask various conditions from the neurological, metabolic, hematological, endocrine, and early childhood cancer groups. Although AFP reference values and clinical utility have been established in adults, evaluating AFP levels in children during the diagnostic process, treatment, and post-treatment surveillance is still associated with numerous diagnostic pitfalls. These challenges arise from the presence of physiologically elevated AFP levels, inconsistent data obtained from different laboratory tests, and the limited population of children with oncologic diseases that have been studied. To address these issues, it is essential to establish updated reference ranges for AFP in this specific age group. A population-based study involving a statistically representative group of patients could serve as a valuable solution for this purpose.

Pathologic and Immunophenotypic Characterization of Syncytial Giant Cell Variant of Pediatric Hepatocellular Carcinoma. A Distinct Subtype

INTRODUCTION

Hepatocellular carcinoma (HCC) in pediatrics has a uniformly poor prognosis. Complete surgical resection or liver transplantation remain the only curative options. In contrast to adult HCC, literature on pediatric HCC is sparse and a majority of the distinct subtypes are undefined with regards to their histology, immunohistochemistry and prognosis.

CASE REPORT

Two infants, one with biliary atresia and another with transaldolase deficiency, underwent living donor liver transplants. Explant-liver histopathology revealed tumor with diffuse neoplastic syncytial giant cell pattern. Immunophenotypic characterization highlighted expression of epithelial cell adhesion molecule, alpha fetoprotein and metallothionein.

CONCLUSION

HCC with syncytial giant cells variant can occur in infants with underlying liver disease, specifically in our experience, with biliary atresia and another with transaldolase deficiency.

Chances of Liver Transplantation in a Patient With Transaldolase Deficiency Complicated by Hepatopulmonary Syndrome

Eyaid's syndrome or Transaldolase Deficiency (TD) (OMIM 606003) is a rare autosomal recessive inborn error of metabolism. In this report, we describe the case of an eight-year-old Saudi girl with a history of hepatosplenomegaly since infancy, who presented to the emergency department for a short history of cough and worsening cyanosis. She had growth retardation, facial dysmorphia, cardiac defect, neutropenia, and thrombocytopenia, besides hepatosplenomegaly. A thorough investigation led to the diagnosis of hepatopulmonary syndrome and whole exome sequencing showed a homozygous frameshift variant in the TALDO1gene, c.793del, p.Gln265fs. Thus, the patient was diagnosed with TD complicated with hepatopulmonary syndrome, and the indication of liver transplantation was discussed.

Cytosolic aldose metabolism contributes to progression from cirrhosis to hepatocarcinogenesis

Oxidative stress modulates carcinogenesis in the liver; however, direct evidence for metabolic control of oxidative stress during pathogenesis, particularly, of progression from cirrhosis to hepatocellular carcinoma (HCC), has been lacking. Deficiency of transaldolase (TAL), a rate-limiting enzyme of the non-oxidative branch of the pentose phosphate pathway (PPP), restricts growth and predisposes to cirrhosis and HCC in mice and humans. Here, we show that mitochondrial oxidative stress and progression from cirrhosis to HCC and acetaminophen-induced liver necrosis are critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Both TAL and AR are confined to the cytosol; however, their inactivation distorts mitochondrial redox homeostasis in opposite directions. The results suggest that AR acts as a rheostat of carbon recycling and NADPH output of the PPP with broad implications for disease progression from cirrhosis to HCC.

Rare Inherited Cholestatic Disorders and Molecular Links to Hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is the most common primary liver cancer affecting adults and the second most common primary liver cancer affecting children. Recent years have seen a significant increase in our understanding of the molecular changes associated with HCC. However, HCC is a complex disease, and its molecular pathogenesis, which likely varies by aetiology, remains to be fully elucidated. Interestingly, some inherited cholestatic disorders that manifest in childhood are associated with early HCC development. This review will thus explore how three genes that are associated with liver disease in childhood (ABCB11, TJP2 and VPS33B) might play a role in the initiation and progression of HCC. Specifically, chronic bile-induced damage (caused by ABCB11 changes), disruption of intercellular junction formation (caused by TJP2 changes) and loss of normal apical–basal cell polarity (caused by VPS33B changes) will be discussed as possible mechanisms for HCC development.