The role of NAD(+)-dependent isocitrate dehydrogenase 3 subunit α in AFB1 induced liver lesion

Application of triple co-cultured cell spheroid model for exploring hepatotoxicity and metabolic pathway of AFB1

The toxicity evaluation suffers from the absence of suitable models capable of replicating in the co-cultured cell microenvironment and the function of specific tissues in vitro. Motivated by this urgent need, this study aimed to describe a novel three-dimensional (3D) liver spheroid model. The model consisted of a triple co-culture of HepG2, EA.hy 926, and LX-2. Subsequently, it was used for the toxicity evaluation of aflatoxin B1 (AFB1), and its advantages over the two-dimensional (2D) model and the mono-type cell spheroid model were assessed. This study examined the effects of AFB1 on cell viability, proliferation, mitochondria, oxidative stress, and cell membranes. The results revealed that AFB1 greatly affected 2D cell membranes and oxidative stress levels (0.01 μg/mL; 24 h), and could also significantly affect 2D cell viability, proliferation, and mitochondria levels (1 μg/mL; 24 h). On the contrary, 3D cells were less susceptible to AFB1. Combined with the analysis of gene expression, both metabolic activation (cytochrome P450; CYP450) and detoxification efficiency (drug-metabolizing enzymes) were found to be higher in 3D cells than in 2D cells. Moreover, 3D cells in triple co-culture outperformed mono-type cell spheroids. Therefore, the advanced 3D co-cultured spheroid model constructed in this study allowed us to more realistically simulate the microenvironment in vitro, and was a valuable and precise model to study mycotoxins.

Aflatoxicosis in Pekin duckling and the effects of treatments with lycopene and silymarin

Background and Aim:

Aflatoxins (AFs) are potent toxic metabolites produced from Aspergillus species. Whose existence in poultry ration leads to drastic economic losses, notably in duck, as the most susceptible poultry species. This study aimed to determine tissue residues of AFs, alterations in selected clinical chemistry variables in serum, mainly during the exposure period, and lycopene and silymarin’s possible roles as herbal treatments against aflatoxicosis in Pekin duckling.

Materials and Methods:

The study used one hundred and twenty one-day-old Pekin ducklings and classified them into four groups comprising 30 ducklings in each group. The control group (G1) ducklings were fed a mycotoxin-free ration, and G2 received a naturally contaminated ration with 30 ppb of AFs. G3 and G4 consumed contaminated rations with AFs with 30 ppb for 2 weeks and were treated with lycopene 100 mg/kg or silymarin 600 mg/kg/food, respectively, for 10 days. Serum activities of alanine transaminase and alkaline phosphatase (ALP), glutamyl transferase, ALP, total protein and albumin creatinine and uric acid concentrations, oxidant/antioxidant parameters (malondialdehyde [MDA], total antioxidant capacity (TAC), glutathione S-transferase (GST), and catalase [CAT]), and hepatic AFs residue were determined. Lycopene and silymarin were used for the treatment of aflatoxicosis for another 10 days.

Results:

Hepatic and kidney parameters were elevated in the AFs intoxicated group and reduced in the lycopene- and silymarin-treated groups. They had elevated MDA and AFs residues with decreased antioxidant parameters (TAC, GST, and CAT) in the AFs group. At the same time, treatment with lycopene or silymarin had reversed the action of AFs on MDA, elevated the hepatic residue, and improved antioxidant activity.

Conclusion:

Lycopene and silymarin, with their potent antioxidant activity, can be used to reverse the harmful effects of AFs on hepatic and kidney tissue.

Effect of IDH3a on glucose uptake in lung adenocarcinoma: A pilot study based on [18 F]FDG

Subunit of isocitrate dehydrogenase 3 (IDH3a) as upstream of the hypoxia-inducible factor was reported highly expressed in malignant tumors, playing an important role in glucose metabolism reprogramming. As one of rate-limiting enzyme in the Krebs cycle, whether high expression of IDH3a affects glucose uptake in tumors has not been elucidated. This study was aimed to investigate the relationship between IDH3a expression and tumor glucose uptake. Sixty-five patients who underwent 2-[¹⁸ F]-2-deoxy-D-glucose ([¹⁸ F]-FDG) positron emission tomography/computed tomography (PET/CT) imaging before surgery and pathologically diagnosed as lung adenocarcinoma were included. All patients were divided into high (n = 31) and low (n = 34) groups according IDH3a expression by immunohistochemistry. Comparatively higher [¹⁸ F]-FDG uptake was found in high IDH3a expression group. Glucose transporter 1 (GLUT1) level was demonstrated to correlate with IDH3a expression, but not for hexokinase 2 (HK2). Furthermore, A549 and H1299 cells experiment showed, the expression of p-AKT and GLUT1 were significantly downregulated after IDH3a interference. The cellular uptake of [¹⁸ F]-FDG and lactate production were significantly reduced in treatment group. In summary, high expression of IDH3a in lung adenocarcinoma patients is associated with higher glucose uptake. IDH3a targets AKT-GLUT1 pathway to affect glucose uptake and metabolites in lung adenocarcinoma.

Risk of Myopathy in Patients in Therapy with Statins: Identification of Biological Markers in a Pilot Study

Statin therapy may induce skeletal muscle damage ranging from myalgia to severe rhabdomyolysis. Our previous preclinical studies showed that statin treatment in rats involves the reduction of skeletal muscle ClC-1 chloride channel expression and related chloride conductance (gCl). An increase of the activity of protein kinase C theta (PKC theta) isoform, able to inactivate ClC-1, may contribute to destabilize sarcolemma excitability. These effects can be detrimental for muscle function leading to drug-induced myopathy. Our goal is to study the causes of statin-induced muscle side effects in patients at the aim to identify biological markers useful to prevent and counteract statin-induced muscle damage. We examined 10 patients, who experienced myalgia and hyper-CK-emia after starting statin therapy compared to 9 non-myopathic subjects not using lipid-lowering drugs. Western Blot (WB) analysis showed a 40% reduction of ClC-1 protein and increased expression of phosphorylated PKC in muscle biopsies of statin-treated patients with respect to untreated subjects, independently from their age and statin type. Real-time PCR analysis showed that despite reduction of the protein, the ClC-1 mRNA was not significantly changed, suggesting post-transcriptional modification. The mRNA expression of a series of genes was also evaluated. MuRF-1 was increased in accord with muscle atrophy, MEF-2, calcineurin (CN) and GLUT-4 transporter were reduced, suggesting altered transcription, alteration of glucose homeostasis and energy deficit. Accordingly, the phosphorylated form of AMPK, measured by WB, was increased, suggesting cytoprotective process activation. In parallel, mRNA expression of Notch-1, involved in muscle cell proliferation, was highly expressed in statin-treated patients, indicating active regeneration. Also, PGC-1-alpha and isocitrate-dehydrogenase increased expression together with increased activity of mitochondrial citrate-synthase, measured by spectrophotometric assay, suggests mitochondrial biogenesis. Thus, the reduction of ClC-1 protein and consequent sarcolemma hyperexcitability together with energy deficiency appear to be among the most important alterations to be associated with statin-related risk of myopathy in humans. Thus, it may be important to avoid statin treatment in pathologies characterized by energy deficit and chloride channel malfunction. This study validates the measure of ClC-1 expression as a reliable clinical test for assessing statin-dependent risk of myopathy.

Studies on the biological functions of CPS1 in AFB1 induced hepatocarcinogenesis

Carbamyl phosphate synthetase 1 (CPS1) was down-regulated in hepatocellular carcinoma (HCC), as treated by aflatoxin B1 (AFB1), a potent hepatocarcinogenesis mycotoxin. In this study, we firstly confirmed that AFB1 down-regulated the expression of CPS1 in a dose-dependent manner. At the meantime, both siRNA knock down of CPS1 and AFB1 treatment inhibited cell proliferation, and induced cell apoptosis. To further analysis the function of CPS1, the interacting proteins of CPS1 were searched by Co-IP, and three interacting proteins including type II cytoskeletal 1 (KRT1), albumin (ALB), and ubiquitin C (UBC) were found. Both KRT1 and ALB were new interacting proteins for CPS1. Our further study showed that CPS1 was regulating interacted and colocalized with KRT1 and ALB, and the intensity correlation was changed by AFB1. KRT1, ALB and CPS1 were all reported to play an important role in differentiation and tissue specialization. These results may offer an increasing understand that CPS1 might have a function in differentiation.