Mitochondrial metabolism and calcium homeostasis in the development of NAFLD leading to hepatocellular carcinoma

Dimethyl fumarate restores Ca2+ dyshomeostasis through activation of the SIRT1 signal to treat nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is characterized by an excessive lipid accumulation in the liver, with a global prevalence of approximately 25 %. While early-stage steatosis is reversible and can be intervened upon, it has the potential to progress to some serious complications, including cirrhosis and even liver cancer. Dimethyl fumarate (DMF), a derivative of fumaric acid shows promise in intervening in certain diseases. However, the precise effect and underlying mechanism of DMF on hepatic steatosis remain unclear. In this study, we demonstrated that DMF mitigates hepatic steatosis in mice subjected to high-fat/high-cholesterol (HFHC) diets. Meanwhile, our in vivo and in vitro results showed that DMF relieves lipid accumulation, oxidative stress, and endoplasmic reticulum (ER) stress. Mechanically, our findings revealed that the effect of DMF on reducing lipid accumulation is linked to the restoration of Ca2+ homeostasis. Furthermore, we found that activation of the SIRT1 signal by DMF plays an important role in correcting the mishandling of the Ca2+ signal, and knockdown of SIRT1 expression reverses the beneficial role of DMF PA-incubated AML12 cells. In conclusion, our results suggested DMF's amelioration of hepatic steatosis is related to the activation of SIRT1-mediated Ca2+ signaling.

Functional Food Chemical Ingredient Strategies for Non-alcoholic Fatty Liver Disease (NAFLD) and Hepatic Fibrosis: Chemical Properties, Health Benefits, Action, and Application

PURPOSE OF REVIEW

The liver is an important digestive gland in the body. Lifestyle and dietary habits are increasingly damaging our liver, leading to various diseases and health problems. Non-alcoholic fatty liver disease (NAFLD) has become one of the most serious liver disease problems in the world. Diet is one of the important factors in maintaining liver health. Functional foods and their components have been identified as novel sources of potential preventive agents in the prevention and treatment of liver disease in daily life. However, the effects of functional components derived from small molecules in food on different types of liver diseases have not been systematically summarized.

RECENT FINDINGS

The components and related mechanisms in functional foods play a significant role in the development and progression of NAFLD and liver fibrosis. A variety of structural components are found to treat and prevent NAFLD and liver fibrosis through different mechanisms, including flavonoids, alkaloids, polyphenols, polysaccharides, unsaturated fatty acids, and peptides. On the other hand, the relevant mechanisms include oxidative stress, inflammation, and immune regulation, and a large number of literature studies have confirmed a close relationship between the mechanisms. The purpose of this article is to examine the current literature related to functional foods and functional components used for the treatment and protection against NAFLD and hepatic fibrosis, focusing on chemical properties, health benefits, mechanisms of action, and application in vitro and in vivo. The roles of different components in the biological processes of NAFLD and liver fibrosis were also discussed.

Zaluzanin C Alleviates Inflammation and Lipid Accumulation in Kupffer Cells and Hepatocytes by Regulating Mitochondrial ROS

Zaluzanin C (ZC), a sesquiterpene lactone isolated from Laurus nobilis L., has been reported to have anti-inflammatory and antioxidant effects. However, the mechanistic role of ZC in its protective effects in Kupffer cells and hepatocytes has not been elucidated. The purpose of this study was to elucidate the efficacy and mechanism of action of ZC in Kupffer cells and hepatocytes. ZC inhibited LPS-induced mitochondrial ROS (mtROS) production and subsequent mtROS-mediated NF-κB activity in Kupffer cells (KCs). ZC reduced mRNA levels of pro-inflammatory cytokines (Il1b and Tnfa) and chemokines (Ccl2, Ccl3, Ccl4, Cxcl2 and Cxcl9). Tumor necrosis factor (TNF)-α-induced hepatocyte mtROS production was inhibited by ZC. ZC was effective in alleviating mtROS-mediated mitochondrial dysfunction. ZC enhanced mitophagy and increased mRNA levels of fatty acid oxidation genes (Pparα, Cpt1, Acadm and Hadha) and mitochondrial biosynthetic factors (Pgc1α, Tfam, Nrf1 and Nrf2) in hepatocytes. ZC has proven its anti-lipid effect by improving lipid accumulation in hepatocytes by enhancing mitochondrial function to facilitate lipid metabolism. Therefore, our study suggests that ZC may be an effective compound for hepatoprotection by suppressing inflammation and lipid accumulation through regulating mtROS.

NREP contributes to development of NAFLD by regulating one-carbon metabolism in primary human hepatocytes

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. We recently discovered that neuronal regeneration-related protein (NREP/P311), an epigenetically regulated gene reprogrammed by parental metabolic syndrome, is downregulated in human NAFLD. To investigate the impact of NREP insufficiency, we used RNA-sequencing, lipidomics, and antibody microarrays on primary human hepatocytes. NREP knockdown induced transcriptomic remodeling that overlapped with key pathways impacted in human steatosis and steatohepatitis. Additionally, we observed enrichment of pathways involving phosphatidylinositol signaling and one-carbon metabolism. Lipidomics analyses also revealed an increase in cholesterol esters and triglycerides and decreased phosphatidylcholine levels in NREP-deficient hepatocytes. Signalomics identified calcium signaling as a potential mediator of NREP insufficiency's effects. Our results, together with the encouraging observation that several single nucleotide polymorphisms (SNPs) spanning the NREP locus are associated with metabolic traits, provide a strong rationale for targeting hepatic NREP to improve NAFLD pathophysiology.

A new perspective on mesenchymal stem cell-based therapy for liver diseases: restoring mitochondrial function

Mesenchymal stem cells (MSCs) have emerged as a promising alternative treatment for liver disease due to their roles in regeneration, fibrosis inhibition, and immunoregulation. Mitochondria are crucial in maintaining hepatocyte integrity and function. Mitochondrial dysfunction, such as impaired synthesis of adenosine triphosphate (ATP), decreased activity of respiratory chain complexes, and altered mitochondrial dynamics, is observed in most liver diseases. Accumulating evidence has substantiated that the therapeutic potential of MSCs is mediated not only through their cell replacement and paracrine effects but also through their regulation of mitochondrial dysfunction in liver disease. Here, we comprehensively review the involvement of mitochondrial dysfunction in the development of liver disease and how MSCs can target mitochondrial dysfunction. We also discuss recent advances in a novel method that modifies MSCs to enhance their functions in liver disease. A full understanding of MSC restoration of mitochondrial function and the underlying mechanisms will provide innovative strategies for clinical applications. Video Abstract.

Implications of MCU complex in metabolic diseases

Metabolic diseases are considered the primary culprit for physical and mental health of individuals. Although the diagnosis of these diseases is relatively easy, more effective and convenient potent drugs are still being explored. Ca2+ across the inner mitochondrial membrane is a vital intracellular messenger that regulates energy metabolism and cellular Ca2+ homeostasis and is involved in cell death. Mitochondria rely on a selective mitochondrial Ca2+ unidirectional transport complex (MCU complex) in their inner membrane for Ca2+ uptake. We found that the channel contains several subunits and undergoes dramatic transformations in various pathological processes, especially in metabolic diseases. In this way, we believe that the MCU complex becomes a target with significant potential for these diseases. However, there is no review linking the two factors, thus hindering the possibility of new drug production. Here, we highlight the connection between MCU complex-related Ca2+ transport and the pathophysiology of metabolic diseases, adding understanding and insight at the molecular level to provide new insights for targeting MCU to reverse metabolism-related diseases.

Identification of common signature genes and pathways underlying the pathogenesis association between nonalcoholic fatty liver disease and atherosclerosis

Background

Atherosclerosis (AS) is one of the leading causes of the cardio-cerebral vascular incident. The constantly emerging evidence indicates a close association between nonalcoholic fatty liver disease (NAFLD) and AS. However, the exact molecular mechanisms underlying the correlation between these two diseases remain unclear. This study proposed exploring the common signature genes, pathways, and immune cells among AS and NAFLD.

Methods

The common differentially expressed genes (co-DEGs) with a consistent trend were identified via bioinformatic analyses of the Gene Expression Omnibus (GEO) datasets GSE28829 and GSE49541, respectively. Further, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. We utilized machine learning algorithms of lasso and random forest (RF) to identify the common signature genes. Then the diagnostic nomogram models and receiver operator characteristic curve (ROC) analyses were constructed and validated with external verification datasets. The gene interaction network was established via the GeneMANIA database. Additionally, gene set enrichment analysis (GSEA), gene set variation analysis (GSVA), and immune infiltration analysis were performed to explore the co-regulated pathways and immune cells.

Results

A total of 11 co-DEGs were identified. GO and KEGG analyses revealed that co-DEGs were mainly enriched in lipid catabolic process, calcium ion transport, and regulation of cytokine. Moreover, three common signature genes (PLCXD3, CCL19, and PKD2) were defined. Based on these genes, we constructed the efficiently predictable diagnostic models for advanced AS and NAFLD with the nomograms, evaluated with the ROC curves (AUC = 0.995 for advanced AS, 95% CI 0.971–1.0; AUC = 0.973 for advanced NAFLD, 95% CI 0.938–0.998). In addition, the AUC of the verification datasets had a similar trend. The NOD-like receptors (NLRs) signaling pathway might be the most crucial co-regulated pathway, and activated CD4 T cells and central memory CD4 T cells were significantly excessive infiltration in advanced NAFLD and AS.

Conclusion

We identified three common signature genes (PLCXD3, CCL19, and PKD2), co-regulated pathways, and shared immune features of NAFLD and AS, which might provide novel insights into the molecular mechanism of NAFLD complicated with AS.

Heart failure with preserved ejection fraction and non-alcoholic fatty liver disease: new insights from bioinformatics

AIMS

Heart failure with preserved ejection fraction (HFpEF) and non-alcoholic fatty liver disease (NAFLD) are related conditions with an increasing incidence. The mechanism of their relationship remains undefined. Here, we aimed to explore the potential mechanisms, diagnostic markers, and therapeutic options for HFpEF and NAFLD.

METHODS AND RESULTS

HFpEF and NAFLD datasets were downloaded from the Gene Expression Omnibus (GEO) database. Common differentially expressed genes (DEGs) were screened for functional annotation. A protein-protein interaction network was constructed based on the STRING database, and hub genes were analysed using GeneMANIA annotation. ImmuCellAI (Immune Cell Abundance Identifier) was employed for analysis of immune infiltration. We also used validation datasets to validate the expression levels of hub genes and the correlation of immune cells. To screen for diagnostic biomarkers, we employed the least absolute shrinkage and selection operator and support vector machine-recursive feature elimination. Drug signature database was used to predict potential therapeutic drugs. Our analyses identified a total of 33 DEGs. Inflammation and immune infiltration played important roles in the development of both diseases. The data showed a close relationship between chemokine signalling pathway, cytokine-cytokine receptor interaction, calcium signalling pathway, neuroactive ligand-receptor interaction, osteoclast differentiation, and cyclic guanosine monophosphate-protein kinase G signalling pathway. We demonstrated that PRF1 (perforin 1) and IL2RB (interleukin-2 receptor subunit beta) proteins were perturbed by the diseases and may be the hub genes. The analysis showed that miR-375 may be a potential diagnostic marker for both diseases. Our drug prediction analysis showed that bosentan, eldecalcitol, ramipril, and probucol could be potential therapeutic options for the diseases.

CONCLUSIONS

Our findings revealed common pathogenesis, diagnostic markers, and therapeutic agents for HFpEF and NAFLD. There is need for further experimental studies to validate our findings.

Mitoxantrone alleviates hepatic steatosis induced by high-fat diet in broilers

Metabolic-dysfunction-associated fatty liver disease (MAFLD) is a common nutritional metabolic disease in poultry that seriously compromises the health of chickens and reduces the economic benefits of the industry. In this study, we investigated the therapeutic effect of mitoxantrone (MTX) on hepatic steatosis in broilers. We constructed a steatosis cell model in vitro by adding oleic acid and palmitic acid to chicken hepatocytes (LMH cells), to examine influence of MTX on fat deposition on LMH cells. To determine the effects of MTX on hepatic steatosis in broiler livers in vivo, broilers were fed a high-fat diet to establish a fatty liver model. Our data show that MTX reduced the triglyceride (TG) levels and total cholesterol levels in LMH cells. In the MAFLD chick model, MTX decreased mRNA abundance of hepatic-lipid-synthesis-related gene such as FASN and increased mRNA abundance of fatty-acid-β-oxidation-related genes such as CPT1, PPARα, and reduced hepatic TG levels. MTX also reduced serum lipid and the percentage of abdominal fat. These results suggest that MTX improves hepatic steatosis in broilers as well as reduces circulating lipid levels and fat accumulation in broilers. Our work provides a promising therapeutic strategy for MAFLD and excessive fat accumulation in broiler chickens.

Aggravation of hepatic lipidosis in red-footed tortoise Chelonoidis carbonaria with age is associated with alterations in liver mitochondria

The occurrence of hepatic lipidosis is commonly reported in different reptilian species, especially in animals under captivity. Liver accumulation of fat is associated with disorders, better described in mammals as non-alcoholic fatty liver diseases (NAFLD), ranging from simple steatosis, to non-alcoholic steatohepatitis (NASH), and to more severe lesions of cirrhosis and hepatocellular carcinoma. Mitochondria play a central role in NAFLD pathogenesis, therefore in this study we characterized livers of ad libitum fed captive red-footed tortoise Chelonoidis carbonaria through histological and mitochondrial function evaluations of juvenile and adult individuals. Livers from adult tortoises exhibited higher levels of lipids, melanomacrophages centers and melanin than juveniles. The observed high score levels of histopathological alterations in adult tortoises, such as microvesicular steatosis, inflammation and fibrosis, indicated the progression to a NASH condition. Mitochondrial oxygen consumption at different respiratory states and with different substrates was 30 to 58% lower in adult when compared to juvenile tortoises. Despite citrate synthase activity was also lower in adults, cardiolipin content was similar to juveniles, indicating that mitochondrial mass was unaffected by age. Mitochondrial Ca²⁺ retention capacity was reduced by 70% in adult tortoises. Overall, we found that aggravation of NAFLD in ad libitum fed captive tortoises is associated with compromised mitochondrial function, indicating a critical role of the organelle in liver disease progression in reptiles.