Metabolic dysfunction-associated steatotic liver disease (MASLD) comprises a spectrum of liver injuries, including steatosis to steatohepatitis (MASH), liver fibrosis, cirrhosis, and relevant complications. The liver mainly comprises hepatocytes, liver sinusoidal endothelial cells (LSECs), Kupffer cells (KCs), immune cells (T cells, B cells), and hepatic stellate cells (HSCs). Crosstalk among these different liver cells, endogenous aberrant glycolipid metabolism, and altered gut dysbiosis are involved in the pathophysiology of MASLD. This review systematically examines advances in understanding the molecular pathogenesis of MASLD, with a focus on emerging therapeutic targets and translational clinical trials. We first delineate the crucial regulatory mechanisms involving diverse liver cells and the gut-liver axis in MASLD development. These cell-specific pathogenic insights offer valuable perspectives for advancing precision medicine approaches in MASLD treatment. Furthermore, we evaluate potential therapeutic targets and summarize clinical trials currently underway. By comprehensively updating the MASLD pathophysiology and identifying promising strategies, this review aims to facilitate the development of novel pharmacotherapies for this increasingly prevalent condition.
Humans ; Fatty Liver/therapy* ; Animals ; Liver/pathology* ; Kupffer Cells/metabolism* ; Hepatocytes/metabolism* ; Hepatic Stellate Cells/metabolism*

The study investigated the specific mechanism by which oxocrebanine, the anti-hepatic cancer active ingredient in Stephania hainanensis, inhibits the proliferation of hepatic cancer cells. Firstly, methyl thiazolyl tetrazolium(MTT) assay, 5-bromodeoxyuridine(BrdU) labeling, and colony formation assay were employed to investigate whether oxocrebanine inhibited the proliferation of HepG2 and Hep3B2.1-7 cells. Propidium iodide(PI) staining was used to observe the oxocrebanine-induced apoptosis of HepG2 and Hep3B2.1-7 cells. Western blot was employed to verify whether apoptotic effector proteins, such as cleaved cysteinyl aspartate-specific protease 3(c-caspase-3), poly(ADP-ribose) polymerase 1(PARP1), B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), Bcl-2 homologous killer(Bak), and myeloid cell leukemia-1(Mcl-1) were involved in apoptosis. Secondly, HepG2 cells were simultaneously treated with oxocrebanine and the autophagy inhibitor 3-methyladenine(3-MA), and the changes in the autophagy marker LC3 and autophagy-related proteins [eukaryotic translation initiation factor 4E-binding protein 1(4EBP1), phosphorylated 4EBP1(p-4EBP1), 70-kDa ribosomal protein S6 kinase(P70S6K), and phosphorylated P70S6K(p-P70S6K)] were determined. The results of MTT assay, BrdU labeling, and colony formation assay showed that oxocrebanine inhibited the proliferation of HepG2 and Hep3B2.1-7 cells in a dose-dependent manner. The results of flow cytometry suggested that the apoptosis rate of HepG2 and Hep3B2.1-7 cells increased after treatment with oxocrebanine. Western blot results showed that the protein levels of c-caspase-3, Bax, and Bak were up-regulated and those of PARP1, Bcl-2, and Mcl-1 were down-regulated in the HepG2 cells treated with oxocrebanine. The results indicated that oxocrebanine induced apoptosis, thereby inhibiting the proliferation of hepatic cancer cells. The inhibition of HepG2 cell proliferation by oxocrebanine may be related to the induction of protective autophagy in hepatocellular carcinoma cells. Oxocrebanine still promoted the conversion of LC3-Ⅰ to LC3-Ⅱ, reduced the phosphorylation levels of 4EBP1 and P70S6K, which can be reversed by the autophagy inhibitor 3-MA. It is prompted that oxocrebanine can inhibit the proliferation of hepatic cancer cells by inducing autophagy. In conclusion, oxocrebanine inhibits the proliferation of hepatic cancer cells by inducing apoptosis and autophagy.
Humans ; Apoptosis/drug effects* ; Autophagy/drug effects* ; Cell Proliferation/drug effects* ; Hep G2 Cells ; Liver Neoplasms/genetics* ; Carcinoma, Hepatocellular/genetics* ; Caspase 3/genetics*

This study explores the therapeutic differences and mechanisms of salt-processed Phellodendri Chinensis Cortex in improving insulin resistance(IR) based on network pharmacology, molecular docking, and cellular experiments. The components and intersection targets of Phellodendri Chinensis Cortex in improving IR were collected from databases, and a "drug-component-target-disease" network and protein-protein interaction(PPI) network were constructed to screen core components and targets. A total of 29 active components and 240 intersection targets were identified, of which 13 were core targets. Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analyses were used to identify key signaling pathways, and molecular docking was performed to validate the binding activity between core components and targets. An IR model in HepG2 cells was induced using insulin combined with high glucose, and the effects of Phellodendri Chinensis Cortex before and after salt-processing on cell glucose consumption were evaluated. The expression of proteins related to the mitogen-activated protein kinase(MAPK) and phosphatidylinositol 3-kinase(PI3K)-protein kinase B(AKT) signaling pathways was detected by Western blot. The cellular experimental results showed that, compared with the model group, glucose consumption in the drug-treated groups was significantly increased(P<0.01), the phosphorylation level of extracellular regulated protein kinase(ERK) was decreased(P<0.05), the phosphorylation levels of PI3K and AKT were increased, and the expression of glucose transporter 4(GLUT4) was also upregulated(P<0.05). Furthermore, the effect of salt-processed Phellodendri Chinensis Cortex was better than that of raw Phellodendri Chinensis Cortex. The study demonstrates that Phellodendri Chinensis Cortex, both before and after salt-processing, improves IR by regulating the expression of related proteins in the MAPK and PI3K-AKT signaling pathways, with enhanced effects after salt-processing.
Humans ; Network Pharmacology ; Phellodendron/chemistry* ; Insulin Resistance ; Drugs, Chinese Herbal/chemistry* ; Hep G2 Cells ; Signal Transduction/drug effects* ; Molecular Docking Simulation ; Protein Interaction Maps/drug effects* ; Proto-Oncogene Proteins c-akt/genetics* ; Phosphatidylinositol 3-Kinases/genetics* ; Glucose/metabolism*

This research investigated the impact of Ganoderma lucidum polysaccharides(GLP) on hepatoblastoma HepG2 and Huh6 cell models, as well as KM mouse model with in situ transplanted tumors, so as to provide a theoretical basis for the clinical application of GLP. Cell viability was assessed through the CCK-8 assay, whereas cell proliferation was evaluated by using the BeyoClick~(TM)EdU-488 test. Cell apoptosis was visualized via Hochest 33258 staining, and autophagy was detected through Mrfp-GFP-LC3 dual fluorescence staining. An in situ tumor transplantation model was created by using HepG2 cells in mice, and mice were treated with normal saline and GLP of 100, 200, and 300 mg·kg~(-1) for tumor count calculation and size assessment. Hematoxylin-eosin(HE) staining was used to observe pathological changes in tumor tissue and vital organs(liver, kidney, lung, spleen, and heart). Western blot analysis was conducted to measure the protein expressions of tumor protein P53(P53), B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), cleaved-caspase-3, Beclin-1, autophagy related protein-5(Atg-5), microtubule-associated protein-light chain-3Ⅰ(LC3Ⅰ)/LC3Ⅱ, autophagy adapter protein 62(P62), protein kinase B(Akt), p-Akt, mammalian target of rapamycin(mTOR), and p-mTOR. The in vitro experiment revealed that compared with the control group, after GLP treatment, tumor cell viability decreased significantly; apoptosis rate increased in a dose-dependent manner, and autophagic flux was inhibited. The in vivo experiments showed that compared with the model group, mice treated with GLP exhibited significantly fewer and smaller tumors. Western blot results showed that compared with the control group or model group, levels of P53, Bax, cleaved-caspase-3, Beclin-1, Atg-5, and LC3-Ⅱ/LC3-Ⅰ were significantly increased after GLP treatment, and the levels of Bcl-2, P62, p-Akt/Akt, and p-mTOR/mTOR were significantly decreased. These outcomes suggest that GLP promotes apoptosis and autophagy in hepatoblastoma cells by regulating the Akt/mTOR pathway.
Animals ; Humans ; Autophagy/drug effects* ; Reishi/chemistry* ; Mice ; Apoptosis/drug effects* ; TOR Serine-Threonine Kinases/genetics* ; Proto-Oncogene Proteins c-akt/genetics* ; Liver Neoplasms/genetics* ; Hepatoblastoma/genetics* ; Polysaccharides/pharmacology* ; Cell Line, Tumor ; Signal Transduction/drug effects* ; Male ; Cell Proliferation/drug effects* ; Hep G2 Cells

Bufalin(BF)has a significant anti-tumor effect, but its clinical application is severely restricted by its high toxicity and poor water solubility. In this study, Scrophularia ningpoensis polysaccharide(SNP)and ursodeoxycholic acid(UDCA) were synthesized into an SNP-UDCA conjugate. BF was encapsulated to prepare BF/SNP-UDCA nanoparticles(NPs). The amphiphilic compound SNP-UDCA was synthesized via the one-step method, and its structure was characterized by Fourier-transform infrared spectroscopy(FT-IR)and proton nuclear magnetic resonance(~1H-NMR). The preparation process of BF/SNP-UDCA NPs was optimized through single-factor investigations. The encapsulation efficiency and drug-loading capacity of BF/SNP-UDCA NPs were determined by high-performance liquid chromatography(HPLC). The molecular form of BF/SNP-UDCA NPs was characterized by using a transmission electron microscope, X-ray diffraction(XRD), and differential scanning calorimeter(DSC). Additionally, the stability of BF/SNP-UDCA NPs was evaluated. The release behavior of BF/SNP-UDCA NPs at different pH values was determined by dialysis. The in vitro anti-tumor effect of BF/SNP-UDCA NPs was evaluated by MTT cytotoxicity assay, flow cytometry for apoptosis, and cellular uptake. The in vitro liver targeting was evaluated by measuring cellular uptake by laser confocal microscopy. The results demonstrated that the SNP-UDCA conjugate was successfully synthesized through an esterification reaction between SNP and UDCA. The preparation process of BF/SNP-UDCA NPs was as follows: the feed ratio of SNP-UDCA to BF was 2∶1, the ultrasonic time was 30 minutes, and the stirring time was two hours. The prepared BF/SNP-UDCA NPs were spherical in shape, with a particle size of(252.74±6.05)nm, an encapsulation efficiency of 65.00%±2.51%, and a drug-loading capacity of 6.80%±0.44%. The XRD and DSC results indicated that BF was encapsulated within the NPs and existed in a molecular or amorphous state. The short-term stability of BF/SNP-UDCA NPs and stability in DMEM medium are good, and their in vitro release behavior followed the first-order equation and was pH-dependent according to the in vitro experiment. Compared with BF, BF/SNP-UDCA NPs at the same concentration showed significantly stronger cytotoxicity and apoptotic effects on HepG2 cells(P<0.05, P<0.01). The uptake of coumarin 6(C6)/SNP-UDCA NPs in HepG2 cells was time-dependent and higher than that in HeLa cells at the same concentration of C6/SNP-UDCA NPs. Moreover, after treatment with SNP, the uptake of C6/SNP-UDCA NPs in HepG2 cells decreased. In conclusion, the preparation process of BF/SNP-UDCA NPs was simple and feasible. BF/SNP-UDCA NPs could enhance the targeting ability and inhibitory effect of BF on liver cancer cells. This study will provide a foundation for liver-targeting nanoformulations of BF.
Bufanolides/pharmacology* ; Nanoparticles/chemistry* ; Humans ; Drug Carriers/chemistry* ; Ursodeoxycholic Acid/chemistry* ; Antineoplastic Agents/pharmacology* ; Polysaccharides/chemistry* ; Scrophularia/chemistry* ; Liver Neoplasms/physiopathology* ; Hep G2 Cells

This study investigates the effect of glycyrrhetinic acid(GA) combined with doxorubicin(DOX) on apoptosis in HepG2 cells and its possible mechanisms. HepG2 cells were cultured in vitro, and cell viability was assessed using the cell counting kit-8(CCK-8) method. Flow cytometry was used to measure apoptosis levels in HepG2 cells. The cells were divided into the following groups: control group(0 μmol·L~(-1)), DOX group(2 μmol·L~(-1)), GA group(150 μmol·L~(-1)), and DOX + GA combination group(2 μmol·L~(-1) DOX + 150 μmol·L~(-1) GA), with treatments given for 24 hours. The colocalization level between the endoplasmic reticulum(ER) and mitochondria was assessed by colocalization fluorescence imaging. Fluorescence probes were used to measure the Ca~(2+) content in the ER and mitochondria. The qRT-PCR and Western blot were used to determine the mRNA and protein expression of sirtuin-3(SIRT3). Co-immunoprecipitation(CO-IP) was applied to investigate the interactions between voltage-dependent anion channel 1(VDAC1) and SIRT3, as well as between VDAC1, glucose-regulated protein 75(GRP75), and inositol 1,4,5-trisphosphate receptor(IP3R). The results showed that the combination of DOX and GA promoted apoptosis in HepG2 liver cancer cells. The colocalization level between the ER and mitochondria was significantly reduced, the Ca~(2+) content in the ER was significantly increased, and the Ca~(2+) content in the mitochondria was significantly decreased. The relative expression of VDAC1, GRP75, and IP3R was significantly reduced, and interactions between VDAC1, GRP75, and IP3R were observed. SIRT3 mRNA and protein expression levels were significantly increased, and an interaction between SIRT3 and VDAC1 was detected. The acetylation level of VDAC1 was significantly decreased. In conclusion, GA combined with DOX induces apoptosis in HepG2 cells by mediating the deacetylation of VDAC1 through SIRT3, weakening the interactions among VDAC1, GRP75, and IP3R. This regulates the formation of endoplasmic reticulum-mitochondrial membrane domains(ERMMDs), affects Ca~(2+) transport between the ER and mitochondria, and ultimately triggers cell apoptosis.
Humans ; Apoptosis/drug effects* ; Hep G2 Cells ; Glycyrrhetinic Acid/pharmacology* ; Doxorubicin/pharmacology* ; Liver Neoplasms/genetics* ; Carcinoma, Hepatocellular/physiopathology* ; Mitochondria/metabolism* ; Endoplasmic Reticulum/metabolism* ; Cell Survival/drug effects* ; Membrane Proteins/genetics*

This study aims to investigate the in vitro mechanisms underlying the beneficial effects of puerarin on hepatic insulin resistance(IR) based on the carbohydrate response element-binding protein(ChREBP)/peroxisome proliferator-activated receptor(PPAR)α/PPARγ axis involved in glucose and lipid metabolism. An IR-HepG2 cell model was established by treating cells with dexamethasone for 48 h, and the cells were then treated with 10, 20, and 40 μmol·L~(-1) puerarin for 24 h. Glucose levels and output in the extracellular fluid were measured by the glucose oxidase method, while cell viability was assessed by the cell counting kit-8(CCK-8) assay. The adenosine triphosphate(ATP) content and glycogen synthesis were evaluated through chemiluminescence and periodic acid-Schiff staining, respectively. Western blot was employed to quantify the protein levels of forkhead box protein O1(FoxO1), phosphorylated forkhead box protein O1 [p-FoxO1(Ser256)], glucagon, phosphofructokinase, liver type(PFKL), pyruvate kinase L-R(PKLR), pyruvate dehydrogenase complex 1(PDHA1), insulin receptor substrate 2(IRS2), phosphatidylinositol 3-kinase p85(PI3KR1), phosphorylated protein kinase B [p-Akt(Thr308)], glycogen synthase(GYS), glycogen phosphorylase, liver type(PYGL), adiponectin(ADPN), ChREBP, PPARα, and PPARγ. Additionally, the protein levels of acetyl-CoA carboxylase 1(ACC1), phosphorylated ATP citrate lyase [p-ACLY(Ser455)], sterol regulatory element binding protein 1c(SREBP-1c), peroxisome proliferator-activated receptor gamma coactivator 1α(PGC1α), carnitine palmitoyltransferase 1α(CPT1α), and glucagon receptor(GCGR) were also determined. Immunofluorescence was employed to visualize the expression and nuclear location of ChREBP/PPARα/PPARγ. Furthermore, quantitative PCR with the antagonists GW6471 and GW9662 was employed to assess Pparα, Pparγ, and Chrebp. The findings indicated that puerarin effectively reduced both the glucose level and glucose output in the extracellular fluid of IR-HepG2 cells without obvious effect on the cell viability, and it increased intracellular glycogen and ATP levels. Puerarin down-regulated the protein levels of FoxO1 and glucagon while up-regulating the protein levels of p-FoxO1(Ser256), PFKL, PKLR, PDHA1, IRS2, PI3KR1, p-Akt(Thr308), GYS, PYGL, ADPN, ACC1, SREBP-1c, p-ACLY(Ser455), PGC1α, CPT1α, and GCGR in IR-HepG2 cells. Furthermore, puerarin up-regulated both the mRNA and protein levels of ChREBP, PPARα, and PPARγ and promoted the translocation into the nucleus. GW6471 was observed to down-regulate the expression of Pparα while up-regulating the expression of Chrebp and Pparγ. GW9662 down-regulated the expression of Pparγ while up-regulating the expression of Pparα, with no significant effect on Chrebp. In summary, puerarin activated the hepatic ChREBP/PPARα/PPARγ axis, thereby coordinating the glucose and lipid metabolism, promoting the conversion of glucose to lipids to exert the blood glucose-lowering effect.
Isoflavones/pharmacology* ; Humans ; PPAR gamma/genetics* ; Hep G2 Cells ; Glucose/metabolism* ; Lipid Metabolism/drug effects* ; PPAR alpha/genetics* ; Liver/drug effects* ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics* ; Insulin Resistance

This paper aims to investigate the hypoglycemic effect and mechanism of berberine in improving energy metabolism based on the multi-pathway regulation of brain and muscle aromatic hydrocarbon receptor nuclear translocal protein 1(BMAL1): cyclin kaput complex of day-night spontaneous output cyclin kaput(CLOCK). The dexamethasone-induced hepatic insulin resistance(IR) HepG2 cell model was used; 0.5, 1, 5, 10, 20 μmol·L~(-1) berberine were administered at 15, 18, 21, 24, 30, 36 h. The time-dose effect of glucose content in extracellular fluid was detected by glucose oxidase method. The optimal dosage and time of berberine were determined for the follow-up study. Glucose oxidase method and chemiluminescence method were respectively performed to detect hepatic glucose output and relative content of ATP in cells; Ca~(2+), reactive oxygen species(ROS), mitochondrial structure and membrane potential were detected by fluorescent probes. Moreover, ultraviolet colorimetry method was used to detect the liver type of pyruvate kinase(L-PK) and phosphoenol pyruvate carboxykinase(PEPCK). In addition, pyruvate dehydrogenase E1 subunit α1(PDHA1), phosphate fructocrine-liver type(PFKL), forkhead box protein O1(FoxO1), peroxisome proliferator-activated receptor gamma co-activator 1α(PGC1α), glucose-6-phosphatase(G6Pase), glucagon, phosphorylated nuclear factor-red blood cell 2-related factor 2(p-Nrf2)(Ser40), heme oxygenase 1(HO-1), NAD(P)H quinone oxidoreductase 1(NQO1), fibroblast growth factor 21(FGF21), uncoupled protein(UCP) 1 and UCP2 were detected by Western blot. BMAL1:CLOCK complex was detected by immunofluorescence double-staining method, combined with small molecule inhibitor CLK8. Western blot was used to detect PDHA1, PFKL, FoxO1, PGC1α, G6Pase, glucagon, Nrf2, HO-1, NQO1, FGF21, UCP1 and UCP2 in the CLK8 group. The results showed that berberine downregulated the glucose content in extracellular fluid in IR-HepG2 cells in a time-and dose-dependent manner. Moreover, berberine inhibited hepatic glucose output and reduced intracellular Ca~(2+) and ROS whereas elevated JC-1 membrane potential and improved mitochondrial structure to enhance ATP production. In addition, berberine upregulated the rate-limiting enzymes such as PFKL, L-PK and PDHA1 to promote glycolysis and aerobic oxidation but also downregulated PGC1α, FoxO1, G6Pase, PEPCK and glucagon to inhibit hepatic gluconeogenesis. Berberine not only upregulated p-Nrf2(Ser40), HO-1 and NQO1 to enhance antioxidant capacity but also upregulated FGF21, UCP1 and UCP2 to promote energy metabolism. Moreover, berberine increased BMAL1, CLOCK and nuclear BMAL1:CLOCK complex whereas CLK8 reduced the nuclear BMAL1:CLOCK complex. Finally, CLK8 decreased PDHA1, PFKL, Nrf2, HO-1, NQO1, FGF21, UCP1, UCP2 and increased FoxO1, PGC1α, G6Pase and glucagon compared with the 20 μmol·L~(-1) berberine group. BMAL1:CLOCK complex inhibited gluconeogenesis, promoted glycolysis and glucose aerobic oxidation pathways, improved the reduction status within mitochondria, protected mitochondrial structure and function, increased ATP energy storage and promoted energy consumption in IR-HepG2 cells. These results suggested that berberine mediated BMAL1:CLOCK complex to coordinate the regulation of hepatic IR cells to improve energy metabolism in vitro.
Humans ; Berberine/pharmacology* ; Gluconeogenesis/drug effects* ; Hep G2 Cells ; Glucose/metabolism* ; Liver/drug effects* ; Energy Metabolism/drug effects* ; Hypoglycemic Agents/pharmacology* ; ARNTL Transcription Factors/genetics* ; Glycolysis/drug effects* ; Oxidation-Reduction/drug effects*

OBJECTIVE: To explore the expression and function of microRNA-144 (miR-144) in β-thalassemia (β-thal). METHODS: The expression of miR-144 during the differentiation of murine erythroleukemia (MEL) cells and mouse embryonic liver-derived erythroid precursor cells was analyzed by real-time fluorescence quantitative PCR (qRT-PCR); The expression levels of miR-144 in peripheral blood and day-14.5 embryonic hepatocytes of wild-type (WT) and β-thal mice, as well as the expression levels of miR-144 in peripheral blood of β-thal patients, was also measured by qRT-PCR. The proportion of Ter119 and CD71 double positive cells in peripheral blood of mild and severe β-thal mice was analyzed by flow cytometry, and the expression levels of miR-144 in the peripheral blood of mild and severe β-thal mice and patients were compared; Bone marrow nucleated erythrocytes from WT mice and β-thal mice were sorted and the expression levels of miR-144 potential target genes were analyzed by gene chip. RESULTS: The expression levels of miR-144 were gradually increased during the directed differentiation of mouse MEL cells and embryonic hepatocytes to the erythroid lineage (r _MEL=0.97, r _{embryonic hepatocytes}=0.86); Compared with WT mice, the expression levels of miR-144 in peripheral blood and 14.5-day embryonic hepatocytes of β-thal mice were significantly increased (P < 0.05); Compared with healthy controls, the patients with β-thal showed an increased expression levels of miR-144 in peripheral blood (P < 0.05). Compared with mice and humans with mild β-thal, the expression levels of miR-144 in peripheral blood of those with severe β-thal were significantly increased (P < 0.05). The expressions of potential target genes of miR-144 in nucleated erythroid cells of the β-thal mice were significantly reduced compared to the WT group. CONCLUSION The expression level of miR-144 gradually increases in erythroid development, and compared with mild β-thal patients, the expression level of miR-144 in the peripheral blood is higher in severe β-thal patients. MiR-144 is expected to be an auxiliary diagnostic indicator for β-thal in clinical practice.
MicroRNAs/metabolism* ; beta-Thalassemia/genetics* ; Animals ; Mice ; Humans ; Cell Differentiation ; Hepatocytes

BACKGROUND: Mitochondria, which harbor their own genome (mtDNA), have attracted attention due to the potential of mtDNA copy number (mtDNA-CN) as an indicator of mitochondrial dysfunction. Although mtDNA-CN has been proposed as a simple and accessible biomarker for metabolic disorders such as metabolic dysfunction-associated steatotic liver disease, the underlying mechanisms and the causal relationship remain insufficiently elucidated. In this investigation, we combined longitudinal epidemiological data, animal studies, and in vitro assays to elucidate the potential causal relationship between reduced mtDNA-CN and the development of steatotic liver disease (SLD). METHODS: We conducted a longitudinal study using data from a health examination cohort initiated in 1981 in Yakumo, Hokkaido, Japan. Data from examinations performed in 2015 and 2022 were analyzed, focusing on 76 subjects without SLD at baseline (2015) to assess the association between baseline mtDNA-CN and subsequent risk of SLD development. In addition, 28-day-old SD rats were fed ad libitum on a 45% high-fat diet and dissected at 2 and 8 weeks of age. Blood and liver mtDNA-CN were measured and compared at each feeding period. Additionally, in vitro experiments were performed using HepG2 cells treated with mitochondrial function inhibitors to induce mtDNA-CN depletion and to examine its impact on intracellular lipid accumulation. RESULTS: Epidemiological analysis showed that the subjects with low mtDNA-CN had a significantly higher odds ratio for developing SLD compared to high (odds ratio [95% confidence interval]: 4.93 [1.08-22.50]). Analysis of the animal model showed that 8 weeks of high-fat diet led to the development of fatty liver and a significant decrease in mtDNA-CN. A further 2 weeks of high-fat diet consumption resulted in a significant decrease in hepatic mtDNA-CN, despite the absence of fatty liver development, and a similar trend was observed for blood. Complementary in vitro experiments revealed that pharmacologically induced mitochondrial dysfunction led to a significant reduction in mtDNA-CN and was associated with increases in intracellular lipid accumulation in HepG2 cells. CONCLUSIONS Our findings suggest that reduced mtDNA-CN may contribute causally to SLD development and could serve as a convenient, noninvasive biomarker for early detection and risk assessment.
Animals ; DNA, Mitochondrial/genetics* ; Humans ; Male ; DNA Copy Number Variations ; Female ; Fatty Liver/blood* ; Rats ; Middle Aged ; Longitudinal Studies ; Rats, Sprague-Dawley ; Adult ; Japan/epidemiology* ; Aged ; Biomarkers/blood* ; Hep G2 Cells ; Diet, High-Fat/adverse effects*