Effects of Long-Chain and Medium-Chain Fatty Acids on Apoptosis and Oxidative Stress in Human Liver Cells with Steatosis

Sodium octanoate mediates GPR84-dependent and independent protection against sepsis-induced myocardial dysfunction

INTRODUCTION

This study aims to evaluate the therapeutic effects of sodium octanoate (SO), a medium-chain fatty acid salt, on SIMD in a murine model and to explore its underlying mechanisms.

METHODS

Male mice were subjected to sepsis models through two methods: intraperitoneal injection of lipopolysaccharide (LPS) and cecal ligation and punction (CLP). Mice received interval doses of SO every 2 hours or 4 hours for a total of six times or three times after LPS treatment. The relationship between SO and G protein-coupled receptor 84 (GPR84) was evaluated through GEO data analysis and molecular docking studies. DBA/2 mice were used to study the role of the GPR84 protein in the SO-mediated protection. Energy metabolomics was utilized to comprehensively assess the impact of SO on the levels of cardiac energy metabolic products in septic mice. histone modification identification techniques were used to further identify the specific sites of histone modification in the hearts of SO-treated septic mice.

RESULTS

SO treatment significantly improved myocardial contractile function, restored the oxidative stress imbalance and enhanced the myocardium's resistance to oxidative injury. SO significantly promotes the expression of GPR84. The loss of GPR84 function markedly attenuates the protective effects of SO. SO enhanced myocardial energy metabolism by promoting the synthesis of acetyl-CoA and upregulating genes involved in fatty acid β-oxidation which were abolished by medium-chain acyl-CoA dehydrogenase (MCAD) knockdown. SO induced histone acetylation, particularly at H3K123 and H3K80.

CONCLUSION

Our study demonstrates that SO exerts protective effects against SIMD through both GPR84-mediated anti-inflammatory and antioxidant actions and GPR84-independent enhancement of myocardial energy metabolism, possibly mediated by MCAD.

Effects of Moringa oleifera Leaf Extract on Liver Histopathology: A Systematic Review

Introduction

Moringa leaves (Moringa oleifera), which are members of the Moringaceae family, are one of the herbal plants that are widely known in Indonesia. Phytochemical contents of moringa leaf, such as flavonoid, quercetin, and phenolic acid, are believed to have an effect on improvement of NAFLD. Therefore, moringa leaf is considered as one the herbal plants that can be used as supplementation in the form of adjuvant therapy to NAFLD. The study objective of our research is to review the effect of giving moringa leaf to the liver, especially the histopathologic features. This study will be conducted on literature review research design, more specifically in the form of a systematic review. Research Method. Five major electronic web databases, including PubMed, Cochrane Library, Google Scholar, Scopus, and ScienceDirect, were used in identifying literature from 2014 to 2023.

Results

From a comprehensive analysis of 13 relevant literature sources, we elucidate the impact of Moringa oleifera leaf extract on liver histopathology, glucose, and lipid metabolism. Furthermore, we provide insights into its safety profile concerning human health.

Conclusion

The phytochemical content of Moringa oleifera leaf extract had shown a significant benefit in plant medicinal sector. From the research that had been done, Moringa oleifera leaf extract contributes to give significant improvement on liver histopathological features, glucose, and lipid metabolism on animal sample model.

Pin1 Exacerbates Non-Alcoholic Fatty Liver Disease by Enhancing Its Activity through Binding to ACC1

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by diffuse hepatocellular steatosis due to fatty deposits in hepatocytes, excluding alcohol and other known liver injury factors. However, there are no specific drugs for the clinical treatment of NAFLD. Therefore, research on the pathogenesis of NAFLD at the cellular and molecular levels is a promising approach to finding therapeutic targets and developing targeted drugs for NAFLD. Pin1 is highly expressed during adipogenesis and contributes to adipose differentiation, but its specific mechanism of action in NAFLD is unclear. In this study, we investigated the role of Pin1 in promoting the development of NAFLD and its potential mechanisms in vitro and in vivo. First, Pin1 was verified in the NAFLD model in vitro using MCD diet-fed mice by Western Blot, RT-qPCR and immunohistochemistry (IHC) assays. In the in vitro study, we used the oleic acid (OA) stimulation-induced lipid accumulation model and examined the lipid accumulation in each group of cells by oil red O staining as well as BODIPY staining. The results showed that knockdown of Pin1 inhibited lipid accumulation in hepatocytes in an in vitro lipid accumulation model and improved lipid indices and liver injury levels. Moreover, in vivo, WT and Pin1-KO mice were fed a methionine-choline deficient (MCD) diet for 4 weeks to induce the NAFLD model. The effects of Pin1 on lipid accumulation, hepatic fibrosis, and oxidative stress were evaluated by biochemical analysis, glucose and insulin tolerance tests, histological analysis, IHC, RT-qPCR and Western blot assays. The results indicate that Pin1 knockdown significantly alleviated hepatic steatosis, fibrosis and inflammation in MCD-induced NAFLD mice, improved glucose tolerance and alleviated insulin resistance in mice. Further studies showed that the AMPK/ACC1 signalling pathway might take part in the process by which Pin1 regulates NAFLD, as evidenced by the inhibition of the AMPK/ACC1 pathway. In addition, immunofluorescence (IF), coimmunoprecipitation (Co-IP) and GST pull-down experiments also showed that Pin1 interacts directly with ACC1 and inhibits ACC1 phosphorylation levels. Our study suggests that Pin1 promotes NAFLD progression by inhibiting the activation of the AMPK/ACC1 signalling pathway, and it is possible that this effect is achieved by Pin1 interacting with ACC1 and inhibiting the phosphorylation of ACC1.

Combination of two-photon fluorescent probes for carboxylesterase and ONOO- to visualize the transformation of nonalcoholic fatty liver to nonalcoholic steatohepatitis in liver orthotopic imaging

As the most common cause of liver diseases, nonalcoholic fatty liver disease (NAFLD) can be classified into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). While NAFL is generally benign, the transition from NAFL to NASH is a cardinal feature of the non-benign liver disease that leads to cirrhosis and cancer, which indicates that tracking the transformation of NAFL to NASH timely is significant for precision management of liver diseases. Therefore, two fluorescent probes (CNFCl and DRNO) have been developed to visualize this pathological event. α-Fluorochloroacetamide and α-ketoamide was employed as the recognition site for carboxylesterase (CE) in CNFCl and peroxynitrite (ONOO-) in DRNO, respectively. CNFCl (λem = 445 nm) and DRNO (λem = 560 nm) showed high specificity and sensitivity towards CE and ONOO- respectively. By incubating with CE/ONOO- for 0.5 h respectively, both the emission intensity of CNFCl (linear range: 0-0.2 U/mL) and DRNO (linear range: 0-17.5 μM) displayed significant enhancement. As a result, the detection limit of CNFCl and DRNO for CE and ONOO- was calculated as 4.2 mU/L and 0.05 μM respectively. More importantly, the emission spectra of CNFCl and DRNO in the presence of CE and ONOO- respectively were cross-talk free under the two-photon excitation of 720 nm. This greatly facilitated the simultaneous detection of CE and ONOO- at distinctive channel, thus ensuring the high fidelity of the detection. These two probes were combined to image the fluctuation of CE and ONOO- during the conversion of NAFL to NASH in vitro and in vivo. It was found that while CE displayed a tendency to rise and then reduce during the transition from NAFL to NASH, ONOO- increased continuously, confirming that the combined imaging by CNFCl and DRNO might visualize the transformation of NAFL to NASH. The results provide robust visual tool to decipher the relationship between the stage of NAFLD and the level of CE/ONOO-. We anticipate this study may open new avenues to distinguish NASH from NAFL, which may further promote the study of intracellular biological activities of CE and the development of NAFLD diagnostic methods.

Gut microbiota metabolites, redox status, and the related regulatory effects of probiotics

Oxidative stress is a state of imbalance between oxidation and antioxidation. It is caused by excess levels of free radicals and leads to the damage of DNA, proteins, and lipids. The crucial role of gut microbiota in regulating oxidative stress has been widely demonstrated. Studies have suggested that the redox regulatory effects of gut microbiota are related to gut microbiota metabolites, including fatty acids, lipopolysaccharides, tryptophan metabolites, trimethylamine-N-oxide and polyphenolic metabolites. In recent years, the potential benefits of probiotics have been gaining increasing scientific interest owing to their ability to modulate gut microbiota and oxidative stress. In this review, we summarise the adverse health effects of oxidative stress and discuss the role of the gut microbiota and its metabolites in redox regulation. Based on the influence of gut microbiota metabolites, the roles of probiotics in preventing oxidative stress are highlighted.

A Medium Chain Fatty Acid, 6-hydroxyhexanoic acid (6-HHA), Protects Against Obesity and Insulin Resistance

Obesity, a worldwide health problem, increases the risk for developing metabolic diseases such as insulin resistance and diabetes. It is well recognized that obesity-associated chronic inflammation plays a key role in the pathogenesis of systemic metabolic dysfunction. Previously, we revealed an anti-inflammatory role for spent culture supernatants isolated from the oral commensal bacterial species Streptococcus gordonii (Sg-SCS). Here, we identified that 6-hydroxyhexanoic acid (6-HHA), a medium chain fatty acid (MCFA), is the one of the key components of Sg-SCS . We found that treatment of 6-HHA in mice fed a high-fat diet (HFD) significantly reduced HFD-mediated weight gain which was largely attributed to a decrease in fat mass. Systemically, 6-HHA improves obesity-associated glucose intolerance and insulin resistance. Furthermore, administration of 6-HHA suppressed obesity-associated systemic inflammation and dyslipidemia. At the cellular level, treatment of 6-HHA ameliorated aberrant inflammatory and metabolic transcriptomic signatures in white adipose tissue of mice with diet-induced obesity (HFD). Mechanistically, we found that 6-HHA suppressed adipocyte-proinflammatory cytokine production and lipolysis, the latter through Gαi-mediated signaling. This work provides direct evidence for the anti-obesity effects of a novel MCFA, which could be a new therapeutic treatment for combating obesity.

KEY POINTS

Hydroxyhexanoic medium chain fatty acids (MCFAs) are dietary and bacterial-derived energy sources, however, the outcomes of using MCFAs in treating metabolic disorders are diverse and complex. The MCFA 6-hydroxyhexanoic acid (6-HHA) is a metabolite secreted by the oral bacterial commensal species Streptococcus gordonii; here we investigated its role in modulating high-fat diet (HFD)-induced metabolic dysfunction. In a murine model of obesity, we found 6-HHA-mediated improvement of diet-mediated adiposity, insulin resistance and inflammation were in part due to actions on white adipose tissue (WAT).6-HHA suppressed proinflammatory cytokine production and lipolysis through Gi-mediated signaling in differentiated white adipocytes.

New insights into the role of dietary triglyceride absorption in obesity and metabolic diseases

The incidence of obesity and associated metabolic diseases is increasing globally, adversely affecting human health. Dietary fats, especially triglycerides, are an important source of energy for the body, and the intestine absorbs lipids through a series of orderly and complex steps. A long-term high-fat diet leads to intestinal dysfunction, inducing obesity and metabolic disorders. Therefore, regulating dietary triglycerides absorption is a promising therapeutic strategy. In this review, we will discuss diverse aspects of the dietary triglycerides hydrolysis, fatty acid uptake, triglycerides resynthesis, chylomicron assembly, trafficking, and secretion processes in intestinal epithelial cells, as well as potential targets in this process that may influence dietary fat-induced obesity and metabolic diseases. We also mention the possible shortcomings and deficiencies in modulating dietary lipid absorption targets to provide a better understanding of their administrability as drugs in obesity and related metabolic disorders.

Medium-chain fatty acids suppress lipotoxicity-induced hepatic fibrosis via the immunomodulating receptor GPR84

Medium-chain triglycerides (MCTs), which consist of medium-chain fatty acids (MCFAs), are unique forms of dietary fat with various health benefits. G protein-coupled 84 (GPR84) acts as a receptor for MCFAs (especially C10:0 and C12:0); however, GPR84 is still considered an orphan receptor, and the nutritional signaling of endogenous and dietary MCFAs via GPR84 remains unclear. Here, we showed that endogenous MCFA-mediated GPR84 signaling protected hepatic functions from diet-induced lipotoxicity. Under high-fat diet (HFD) conditions, GPR84-deficient mice exhibited nonalcoholic steatohepatitis (NASH) and the progression of hepatic fibrosis but not steatosis. With markedly increased hepatic MCFA levels under HFD, GPR84 suppressed lipotoxicity-induced macrophage overactivation. Thus, GPR84 is an immunomodulating receptor that suppresses excessive dietary fat intake-induced toxicity by sensing increases in MCFAs. Additionally, administering MCTs, MCFAs (C10:0 or C12:0, but not C8:0), or GPR84 agonists effectively improved NASH in mouse models. Therefore, exogenous GPR84 stimulation is a potential strategy for treating NASH.

Acute Oral Toxicity and Genotoxicity Test and Evaluation of Cinnamomum camphora Seed Kernel Oil

Cinnamomum camphora seed kernel oil (CCSKO) is one of the important natural medium chain triglycerides (MCT) resources, with more than 95.00% of medium chain fatty acids found in the world, and has various physiological effects. However, CCSKO has not been generally recognized as a safe oil or new food resource yet. The acute oral toxicity test and a standard battery of genotoxicity tests (mammalian erythrocyte micronucleus test, Ames test, and in vitro mammalian cell TK gene mutation test) of CCSKO as a new edible plant oil were used in the study. The results of the acute oral toxicity test showed that CCSKO was preliminary non-toxic, with an LD50 value higher than 21.5 g/kg body weight. In the mammalian erythrocyte micronucleus test, there was no concentration-response relationship between the dose of CCSKO and micronucleus value in polychromatic erythrocytes compared to the negative control group. No genotoxicity was observed in the Ames test in the presence or absence of S9 at 5000 μg/mL. In vitro mammalian cell TK gene mutation test showed that CCSKO did not induce in vitro mammalian cell TK gene mutation in the presence or absence of S9 at 5000 μg/mL. These results indicated that CCSKO is a non-toxic natural medium-chain oil.

Serum metabolomics-based heterogeneities and screening strategy for metabolic dysfunction-associated fatty liver disease (MAFLD)

BACKGROUND AND AIMS

Metabolic dysfunction-associated fatty liver disease (MAFLD) brings heavy clinical and economic burdens to society, while understandings on heterogeneities are limited.

MATERIALS AND METHODS

We conducted a serum metabolomics study to reveal the metabolic heterogeneities and develop a diagnostic strategy for MAFLD using a discovery set consisting of 122 biopsy-proven MAFLD patients [lean (n = 12), overweight (n = 20), obese (n = 74), type 2 diabetes mellitus (T2DM, n = 16)] and 35 controls, and a validation set containing 60 biopsy-proven MAFLD patients (20 lean, 20 obese and 20 T2DM) and 20 controls.

RESULTS

Mitochondrial dysfunction, destructed phospholipids homeostasis, and folate deficiency were most severe in MAFLD concurrent T2DM patients. Formiminoglutamate, sphinganine and sphingosine correlated positively with HbA1c, while glycoursodeoxycholicacidsulfate correlated positively with AST. Additionally, the linear discriminant analysis (LDA) model using metabolites 5-hydroxyhexanoate, ribitol and formiminoglutamate demonstrated pretty good performance in screening for MAFLD patients, with AUC for validation samples being 0.94 (CI: 0.88-1.0). For easier clinical applications, an M-index based on the three metabolites was further designed.

CONCLUSION

Our study supports that MAFLD concurrent T2DM patients deserve particular attentions in clinical follow-up, and paves the way for developing more effective diagnostic options in future studies.

Ca:Mg ratio, medium-chain fatty acids, and the gut microbiome

BACKGROUND & AIMS

Ketogenic medium-chain fatty acids (MCFAs) with profound health benefits are commonly found in dairy products, palm kernel oil and coconut oil. We hypothesize that magnesium (Mg) supplementation leads to enhanced gut microbial production of MCFAs and, in turn, increased circulating MCFAs levels.

METHODS

We tested this hypothesis in the Personalized Prevention of Colorectal Cancer Trial (PPCCT) (NCT01105169), a double-blind 2 × 2 factorial randomized controlled trial enrolling 240 participants. Six 24-h dietary recalls were performed for all participants at the baseline and during the intervention period. Based on the baseline 24-h dietary recalls, the Mg treatment used a personalized dose of Mg supplementation that would reduce the calcium (Ca): Mg intake ratio to around 2.3. We measured plasma MCFAs, sugars, ketone bodies and tricarboxylic acid cycle (TCA cycle) metabolites using the Metabolon's global Precision Metabolomics™ LC-MS platform. Whole-genome shotgun metagenomics (WGS) sequencing was performed to assess microbiota in stool samples, rectal swabs, and rectal biopsies.

RESULTS

Personalized Mg treatment (mean dose 205.58 mg/day with a range from 77.25 to 389.55 mg/day) significantly increased the plasma levels of C7:0, C8:0, and combined C7:0 and C8:0 by 18.45%, 25.28%, and 24.20%, respectively, compared to 14.15%, 10.12%, and 12.62% decreases in the placebo arm. The effects remain significant after adjusting for age, sex, race and baseline level (P = 0.0126, P = 0.0162, and P = 0.0031, respectively) and FDR correction at 0.05 (q = 0.0324 for both C7:0 and C8:0). Mg treatment significantly reduced the plasma level of sucrose compared to the placebo arm (P = 0.0036 for multivariable-adjusted and P = 0.0216 for additional FDR correction model) whereas alterations in daily intakes of sucrose, fructose, glucose, maltose and C8:0 from baseline to the end of trial did not differ between two arms. Mediation analysis showed that combined C7:0 and C8:0 partially mediated the effects of Mg treatment on total and individual ketone bodies (P for indirect effect = 0.0045, 0.0043, and 0.03, respectively). The changes in plasma levels of C7:0 and C8:0 were significantly and positively correlated with the alterations in stool microbiome α diversity (r = 0.51, p = 0.0023 and r = 0.34, p = 0.0497, respectively) as well as in stool abundance for the signatures of MCFAs-related microbiota with acyl-ACP thioesterase gene producing C7:0 (r = 0.46, p = 0.0067) and C8:0 (r = 0.49, p = 0.003), respectively, following Mg treatment.

CONCLUSIONS

Optimizing Ca:Mg intake ratios to around 2.3 through 12-week personalized Mg supplementation leads to increased circulating levels of MCFAs (i.e. C7:0 and C8:0), which is attributed to enhanced production from gut microbial fermentation and, maybe, sucrose consumption.

MCFA alleviate H2 O2 -induced oxidative stress in AML12 cells via the ERK1/2/Nrf2 pathway

Oxidative stress is an important factor in the occurrence and development of liver disease. Medium-chain fatty acids (MCFAs) have potential antioxidant function, whereas the exact underlying mechanism of MCFA in oxidative injury of hepatocytes remains unclear. In our present study, three different MCFAs, 8-carbon octanoic acid (OA), 10-carbon capric acid (CA), and 12-carbon lauric acid (LA), have been performed to observe their protective action for hepatocyte under the H₂ O₂ challenge. The result showed that MCFA treatment significantly increased the cell viability, T-AOC, and expression of antioxidant-related genes in AML12 cells under oxidative stress condition, and reduced reactive oxygen species (ROS) production. Moreover, MCFA treatment significantly increased the protein expression of Nrf2 and the phosphorylation level of ERK1/2; LA treatment significantly promoted the Nrf2 nuclear translocation. With a further test, the rescue ability of MCFA was blocked by treating with the ERK inhibitor U0126. Overall, our data suggested that MCFA treatment has positive impact on protecting AML12 cells against oxidative stress through ERK1/2/Nrf2 pathway.

Circular RNA NF1-419 Inhibits Proliferation and Induces Apoptosis by Regulating Lipid Metabolism in Astroglioma Cells

BACKGROUND

Astroglioma is the most common primary tumor of the central nervous system. Currently, there is no effective treatment for astroglioma. In the present study, the extract (L3) from Ganoderma Lucidum (G. lucidum) was found to inhibit the growth of astroglioma U87 cells and change the expression of circular RNAs (circRNAs). One of these, including the circular NF1-419 (circNF1-419), was of interest because NF1 gene is a classic tumor suppressor gene.

OBJECTIVES

The functional role of circ-NF1-419 in the inhibition of astroglioma cells remains unknown. This study focuses on the role of circNF1-419 in functional abnormalities of U87 astroglioma cells and aims to elaborate on its regulatory mechanism.

METHODS

The circNF1-419 overexpressing U87 (U87-NF1-419) cells were constructed. We generated U87-NF1-419 to evaluate the role of circNF1-419 on cell cycle, apoptosis, proliferation, tumor growth and metabolic regulation. Finally, we used docking screening to identify compounds in G. lucidum extracts that target circ-419.

RESULTS

U87-NF1-419 can promote cell apoptosis and regulate lipid metabolism through glycerophospholipid metabolism and retrograde endocannabinoid signaling. Further examinations revealed that the expression of metabolic regulators, such as L-type voltage-operated calcium channels (L-VOCC), phospholipase C-β3 (PLCβ3), Mucin1, cationic amino acid transporter 4 (CAT4), cationic amino acid transporter 1 (CAT1) and a kinase (PRKA) anchor protein 4 (AKAP4) was inhibited, while phosphatidylserine synthase 1 (PTDSS1) was enhanced in U87-NF1-419 cells. In vivo experiments showed that circNF1-419 inhibits tumor growth in BALB/C nude mice, and enhanced AKAP4 and PTDSS1 in tumor tissues. The virtual docking screening results supported that ganosporeric acid A, ganodermatriol, ganoderic acid B and α-D-Arabinofuranosyladenine in L3 could activate circNF1-419 in astroglioma treatment.

CONCLUSION

This study indicated that circNF1-419 could be a therapeutic target for the clinical treatment of astroglioma. L3 from Ganoderma Lucidum (G. lucidum) could inhibit astroglioma growth by activating circNF1-419.

The Impact of Medium Chain and Polyunsaturated ω-3-Fatty Acids on Amyloid-β Deposition, Oxidative Stress and Metabolic Dysfunction Associated with Alzheimer's Disease

Alzheimer’s disease (AD), the most common cause of dementia in the elderly population, is closely linked to a dysregulated cerebral lipid homeostasis and particular changes in brain fatty acid (FA) composition. The abnormal extracellular accumulation and deposition of the peptide amyloid-β (Aβ) is considered as an early toxic event in AD pathogenesis, which initiates a series of events leading to neuronal dysfunction and death. These include the induction of neuroinflammation and oxidative stress, the disruption of calcium homeostasis and membrane integrity, an impairment of cerebral energy metabolism, as well as synaptic and mitochondrial dysfunction. Dietary medium chain fatty acids (MCFAs) and polyunsaturated ω-3-fatty acids (ω-3-PUFAs) seem to be valuable for disease modification. Both classes of FAs have neuronal health-promoting and cognition-enhancing properties and might be of benefit for patients suffering from mild cognitive impairment (MCI) and AD. This review summarizes the current knowledge about the molecular mechanisms by which MCFAs and ω-3-PUFAs reduce the cerebral Aβ deposition, improve brain energy metabolism, and lessen oxidative stress levels.

Effects of Flutriafol Fungicide on the Lipid Accumulation in Human Liver Cells and Rat Liver

Flutriafol (FTF) is a triazole fungicide that can cause liver toxicity through the ingestion of its residues in food and water. However, little is known about the liver toxicity of FTF, particularly nonalcoholic fatty liver disease (NAFLD) in humans. Therefore, the purpose of this study was to investigate whether FTF induces NAFLD in human liver cells and animal liver. HepG2 cells and Sprague Dawley (SD) rats were treated with FTF at doses of 0–640 µM for 24 h and 0–150 mg/kg bw/day for 28 days, respectively. FTF (80, 160, and 320 µM) treatment to cells induced lipid accumulation. FTF (80 and 160 µM)-treated cells had higher levels of cytochrome P450 enzymes and reactive oxygen species and increased mitochondrial membrane potential loss than the control. FTF also increased the mRNA levels of antioxidant enzymes through oxidative stress and nuclear factor erythroid 2-related factor 2 pathways in HepG2 cells. However, a higher level of FTF (320 µM) induced apoptosis. The treatment of SD rats with FTF (2.5–150 mg/kg bw/day) induced fatty infiltration in the liver by impairing liver metabolism and inducing apoptosis. Therefore, our data suggest that human exposure to FTF residues may be a risk factor for liver diseases, such as NAFLD.

Major royal jelly proteins prevents NAFLD by improving mitochondrial function and lipid accumulation through activating the AMPK / SIRT3 pathway in vitro

Nonalcoholic fatty liver disease (NAFLD) is a metabolic syndrome, whose main characteristics are excessive lipid accumulation and oxidative stress. Major royal jelly proteins (MRJPs) is a kind of water-soluble protein, which is abundant in royal jelly (RJ). The aim of this study was to evaluate the effect of MRJPs on lipid accumulation and oxidative stress of liver cells. Here, we first optimized the conditions for extracting MRJPs from RJ and identified the extraction effect and product by SDS-PAGE. Then, we used oleic acid (OA) of 1.0 mM to induce hepatocytes for 24 hr to establish a stable cell models of lipid accumulation, and we found that pre-administration (24 hr) of MRJPs (0.2, 0.5, and 1.0 g/L) could significantly reduce the lipid drop content and triglyceride level in the model cells, and simultaneously reduce the alanine aminotransferase and aspertate aminotransferase levels in the cell culture supernatant. In addition, pre-incubation (24 hr) with MRJPs (0.2, 0.5, and 1.0 g/L) could restore superoxide dismutase (SOD) level and mitochondrial membrane potential as compared with OA group. Furthermore, MRJPs administration significantly upregulated the expression of Silent Information Regulator 2 Associated Protein 3, mitochondrial superoxide dismutase (SOD2), and cytochrome c oxidase subunit IV in OA-treated HepG2 cells. The study for the first time provides evidences on the lipid-lowering effect of MRJPs at the cellular level, which can further provide support for the development and application of polypeptide drugs in the future, and can also provide a choice for the prevention and treatment of liver metabolic diseases represented by NAFLD. PRACTICAL APPLICATION: Our study proved that MRJPs had substantial preventing effect on OA-induced lipid accumulation and mitochondrial dysfunction in HepG2 cells. This research can further provide theoretical support for the development and application of peptide drugs in the future. Besides, it can not only further broaden our understanding of NAFLD and other diseases, but also provide ideas for research on oxidative stress and lipid accumulation in the body.

Abnormalities of Serum Fatty Acids in Children With Henoch-Schönlein Purpura by GC-MS Analysis

Purpose: The objectives of this work were to test the levels of serum medium- and long- chain fatty acids (MLCFAs) in children and to discover their possible relationship with Henoch-Schönlein Purpura (HSP), also known as Immunoglobulin A vasculitis. Methods: A total of 57 children with HSP (HSP group) and 28 healthy children (CON group) were recruited for this study. Serum specimens were collected to detect the compositions and contents of MLCFAs by gas chromatography with mass spectrometry (GC-MS) analysis. Results: The contents of all detected 37 MLCFAs in the HSP group were higher than the healthy group. Thirty-one species of MLCFAs were discovered to have a significant difference (p < 0.05) in two groups. Comparing to healthy controls, there were 31, 31, 18 fatty acids showed a statistical difference in the untreated group, regular treated group, and withdrawal group of HSP, respectively. The trend of fatty acids in the three HSP groups was similar to the healthy controls, as well as the untreated group and regular treated group changed more obviously than the withdrawal group. Almitate (C16:0) and 18 carbon atoms (C18) of fatty acids were abundant in all three HSP groups, divided according to the treatment of glucocorticoid. Some fatty acids were found having considerable differences (p < 0.05) in three groups. Monounsaturated fatty acids (MUFAs), including elaidate (C18:1T), cis-11,14,17-eicosatrienoic acid ester (C20:1), and cis-15-tetracosenoate (C24:1), were distinctly higher in HSP children with renal damage. Conclusion: Our study revealed that the abnormalities in MLCFA may be associated with the development of HSP. Another interesting finding was that fatty acids contents were changing during the glucocorticoid treatment. Meanwhile, long-chain MUFAs may have an impact on renal damage in HSP patients. Further studies need to be carried out in order to explore the specific mechanism of fatty acids in the course of HSP.

Increased antioxidant response in medium-chain acyl-CoA dehydrogenase deficiency: does lipoic acid have a protective role?

BACKGROUND

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency (MCADD) is the most frequent fatty acid oxidation (FAO) defect in humans. MCAD-deficient fibroblasts are more resistant to oxidative stress-induced cell death than other FAO defects and healthy controls.

METHODS

Herein we investigate the antioxidant response and mitochondrial function in fibroblasts from MCAD-deficient patients (c.985 A>G/c.985 A>G) and healthy controls.

RESULTS

MCAD-deficient fibroblasts showed increased level of mitochondrial superoxide, while lipids were less oxidatively damaged, and higher amount of manganese superoxide dismutase were detected compared to healthy controls, showing forceful antioxidant system in MCADD. We showed increased maximal respiration and reserve capacity in MCAD-deficient fibroblasts compared to controls, indicating more capacity through the tricarboxylic acid (TCA) cycle and subsequently respiratory chain. This led us to study the pyruvate dehydrogenase complex (PDC), the key enzyme in the glycolysis releasing acetyl-CoA to the TCA cycle. MCAD-deficient fibroblasts displayed not only significantly increased PDC but also increased lipoylated PDC protein levels compared to healthy controls.

CONCLUSIONS

Based on these findings, we raise the interesting hypothesis that increased PDC-bound lipoic acid, synthesized from accumulated octanoic acid in MCADD, may affect the cellular antioxidant pool in MCADD.

Chrysanthemum ethanol extract induced loss of Kupffer cells via the mitochondria-dependent apoptotic pathway

Chrysanthemum has been viewed as an important traditional Chinese medicine (TCM) with a long history. Research studies indicated many potential pharmaceutical effects of chrysanthemum extract. However, hardly any investigation has been performed to describe its toxicity. In this study, acute application of chrysanthemum ethanol extract (CEE, 300 mg kg^-1) was found to induce apoptosis of hepatic Kupffer cells in vivo. CEE was also observed to induce apoptosis of RAW264.7 cells in a dose- and time-dependent manner. Further analysis using flow cytometry and western blotting revealed that CEE induced apoptosis of RAW264.7 cells via a mitochondria-dependent pathway. After a HPLC combined screening assay, we narrowed down the toxicity caused by the petroleum extract of CEE (CEE-PE, 66 μg mL^-1). In vivo effects of CEE-PE were also tested in mice. Additionally, nine potential toxic compounds were isolated and identified from CEE-PE. In all, we found that components with small polarities in CEE could induce apoptosis of Kupffer cells and macrophages via a mitochondrial dependent pathway, which might draw attention to the safety issues of everyday use of chrysanthemum.

Effects of medium- and long-chain fatty acids on acetaminophen- or rifampicin-induced hepatocellular injury

Drug-induced liver injury (DILI) is one of the common adverse effects of drug therapy, which is closely associated with oxidative stress, apoptosis, and inflammation response. Medium-chain fatty acids (MCFA) were reported to relieve inflammation and attenuate oxidative stress. However, little has been known about the hepatoprotective effects of MCFA in DILI. In the present study, acetaminophen (AP) and rifampicin (RFP) were used to establish DILI models in LO2 cells, and the cytoprotective effects of MCFA on hepatocellular injury were investigated. Results showed that the optimal condition for the DILI model was treatment with 10 mM AP or 600 µM RFP for 24 hr. LCFA treatment markedly reduced the cell viability and increased the activities of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase. Meanwhile, LCFA treatment aggravated cell apoptosis, mitochondrial dysfunction, and oxidative stress. The mRNA and protein expression levels of inflammatory cytokines (IL-1β and TNF-α) were significantly elevated by LCFA. In contrast, MCFA treatment did not significantly affect cell viability, apoptosis, oxidative, stress and inflammation, and it did not produce the detrimental effects on DILI models. Therefore, we proposed that MCFA may be more safe and suitable than LCFA as nutrition support or the selection of daily dietary oil and fat for the patients with DILI.

The protective effects of pretreatment with resveratrol in cyclophosphamide-induced rat ovarian granulosa cell injury: In vitro study

Cyclophosphamide (Cy), a chemotherapeutic agent, is widely used to treat tumoursand is also associated with premature ovarian insufficiency. 4-Hydroperoxycyclophosphamide (4-HC), an active metabolite of Cy, was used for in vitro experiments. Granulosa cells (GCs) are crucial for maintaining follicle development and are also used in reproductive toxicity research in vitro. Resveratrol (Res), a polyphenolic compound, exhibits multiple effects in cells and animal models. To date, whether Res pretreatment has a protective effect on GCs induced by Cy remains unclear. This was an in vitro study, and primary cultures of rat GCs were used. Rat GCs were treated with 4-HC alone, Res + 4-HC or Res + 4-HC + EX527, and GCs survival rates, oxidative stress levels, apoptosis rates and related Sirt1 pathway proteins were evaluated. We demonstrated that 4-HC caused GC damage by increasing oxidative stress, autophagy and apoptosis. Res pretreatment improved 4-HC-induced GC damage by increasing Sirt1 expression, reducing oxidative stress levels and decreasing Beclin1, LC3B, Bax and Caspase-3 levels. Importantly, the addition of EX527, which is a selective inhibitor of Sirt1, reversed the protective effect of Res pretreatment, indicating that Sirt1 may be an important mediator of the protective effect of Res. Taken together, we demonstrated that Res may be a potential drug to improve fertility preservation for patients undergoing chemotherapy.

The Medium-Chain Fatty Acid Receptor GPR84 Mediates Myeloid Cell Infiltration Promoting Steatohepatitis and Fibrosis

Medium-chain fatty acids (MCFAs) have been associated with anti-steatotic effects in hepatocytes. Expression of the MCFA receptor GPR84 (G protein-coupled receptor 84) is induced in immune cells under inflammatory conditions and can promote fibrogenesis. We aimed at deciphering the role of GPR84 in the pathogenesis of non-alcoholic steatohepatitis (NASH), exploring its potential as a therapeutic target. GPR84 expression is upregulated in liver from patients with non-alcoholic fatty liver disease (NAFLD), correlating with the histological degree of inflammation and fibrosis. In mouse and human, activated monocytes and neutrophils upregulate GPR84 expression. Chemotaxis of these myeloid cells by GPR84 stimulation is inhibited by two novel, small molecule GPR84 antagonists. Upon acute liver injury in mice, treatment with GPR84 antagonists significantly reduced the hepatic recruitment of neutrophils, monocytes, and monocyte-derived macrophages (MoMF). We, therefore, evaluated the therapeutic inhibition of GPR84 by these two novel antagonists in comparison to selonsertib, an apoptosis signal-regulating kinase 1 (ASK1) inhibitor, in three NASH mouse models. Pharmacological inhibition of GPR84 significantly reduced macrophage accumulation and ameliorated inflammation and fibrosis, to an extent similar to selonsertib. In conclusion, our findings support that GPR84 mediates myeloid cell infiltration in liver injury and is a promising therapeutic target in steatohepatitis and fibrosis.

Abnormal expression of liver autophagy and apoptosis-related mRNA in fatty liver haemorrhagic syndrome and improvement function of resveratrol in laying hens

Fatty liver haemorrhagic syndrome (FLHS) is characterized by hepatic rupture and haemorrhage leading to sudden death in laying hens. Resveratrol (Res) is a natural polyphenol with antioxidant and anti-inflammatory effects that can ameliorate chronic liver disease. The aim of this study was to investigate the improved effect of Res on the altered expression of autophagy and apoptosis-related genes in laying hens with FLHS. A total of 144 healthy 150-day-old laying hens were randomly divided into four groups: control group (standard diet), HELP group (high-energy-low-protein (HELP) diet), HELP + Res group (HELP diet with 400 mg/kg Res) and Res group (standard diet with 400 mg/kg Res). Histopathological lesions of the liver and the mRNA levels of Beclin-1, Atg5, Atg7, p62, Bcl-2, Bax and Caspase-3 on days 40, 80, and 120 were measured. The results showed that lipid accumulation and hepatocyte damage in the HELP group were more serious than those in the HELP + Res group. The mRNA levels of Beclin-1, Atg5, Atg7, and Bcl-2 in the HELP and HELP + Res groups were strikingly declined (P < 0.01) compared to the control group, and their mRNA levels were markedly higher in HELP group than those in the HELP + Res group (P < 0.05). Additionally, the mRNA levels of p62, Bax and Caspase-3 were significantly increased in the HELP and HELP + Res groups (P < 0.01 or P < 0.05), but their mRNA levels in the HELP group were higher than those in the HELP + Res group (P < 0.05). Collectively, FLHS could induce severe lipid accumulation, abnormal mRNA levels of liver autophagy and apoptosis-related genes. Res as a dietary supplement could attenuate these abnormal changes.

Platelets Apoptosis and Clearance in The Presence of Sodium Octanoate during Storage of Platelet Concentrate at 4˚C

Objective

Platelet (PLT) storage at 4˚C has several benefits, however, it is accompanied by increased clearance of PLTs after transfusion. In this study, we evaluated the potential of sodium octanoate (SO) for reducing apoptosis and clearance rate of PLTs after long-term storage in cold.

Materials and Methods

In this experimental study, PLT concentrates (PCs) were stored for 5 days under the following three conditions: 20-24˚C, 4˚C, and 4˚C in the presence of SO. To measure the viability of PLTs, the water-soluble tetrazolium salt (WST-1) assay was performed. Phosphatidylserine (PS) exposure was determined on PLTs using flow cytometry technique. The amount of human active caspase-3 was determined in PLTs using an enzyme-linked immunosorbent assay. Additionally, the amount of PLT ingestion or clearance was determined by using HepG2 cell line.

Results

The viability was higher in the SO-treated PLTs compared to the other groups. The level of PS exposure on PLTs was lower in the SO-treated PLTs compared to the other groups. The amount of active caspase-3 increased in all groups during 5-day storage. The highest increase in the amount of caspase-3 levels was observed at cold temperature. However, PLTs kept at 4˚C in the presence of SO had a lower amount of active caspase-3 compared to PLTs kept at 4˚C. The amount of PLTs removal by HepG2 cells was increased for 4˚C-kept PLTs but it was lower for PLTs kept at 4˚C in the presence of SO but, the differences were not significant (P>0.05).

Conclusion

SO could partially moderate the effects of cold temperature on apoptosis and viability of platelets. It also decreases the ingestion rate of long-time refrigerated PLTs in vitro. Further studies using higher numbers of samples are required to demonstrate the effect of SO on reducing the clearance rate of PLTs.

Obesity Mediates Apoptosis and Extracellular Matrix Metabolic Imbalances via MAPK Pathway Activation in Intervertebral Disk Degeneration

Obesity may promote intervertebral disc degeneration (IDD) by non-mechanical means, by influencing levels of free fatty acids which could impair cell metabolism. This study aims to establish metabolic factors in obesity-related IDD independent of mechanical loading. In clinical study, we retrospectively reviewed 128 volunteers (73 males, 55 females, aged 29-88 years) and compared their grades of disk degeneration with obesity-related factors such as body weight, BMI, and serum lipid levels. Clinically, the IDD group showed increased age, BMI and serum triglyceride. Triglyceride was a significant risk factor for IDD even after correction for BMI and age (P = 0.007). In obesity animal model, rats were fed a high-fat diet (HFD) in order to study its effects on disk metabolism and apoptosis. HFD rats had significantly higher serum levels of lipids, including triglyceride and non-esterified fatty acid, and showed significantly decreased markers of anabolism, increased catabolism and apoptosis in disk. Finally, rat nucleus pulposus (NP) cells were stimulated in vitro with a fatty acid (palmitic acid, PA) to gauge its effects on cell metabolism and apoptosis. Cell culture studies showed that NP cells exposed to PA showed increased apoptosis for activation of caspase 3, 7, 9, and PARP, which was primarily via the MAPK signal pathway, especially ERK pathway. In conclusion, hypertriglyceridemia can lead to IDD, independently of age and BMI. Hypertriglyceridemia appears to mediate disk cell apoptosis and matrix catabolism primarily via the ERK pathway.

The fatty acid oxidation enzyme long-chain acyl-CoA dehydrogenase can be a source of mitochondrial hydrogen peroxide

Fatty acid oxidation (FAO)-driven H₂O₂ has been shown to be a major source of oxidative stress in several tissues and disease states. Here, we established that the mitochondrial flavoprotein long-chain acyl-CoA dehydrogenase (LCAD), which catalyzes a key step in mitochondrial FAO, directly produces H₂O₂in vitro by leaking electrons to oxygen. Kinetic analysis of recombinant human LCAD showed that it produces H₂O₂ 15-fold faster than the related mitochondrial enzyme very long-chain acyl-CoA dehydrogenase (VLCAD), but 50-fold slower than a bona fide peroxisomal acyl-CoA oxidase. The rate of H₂O₂ formation by human LCAD is slow compared to its activity as a dehydrogenase (about 1%). However, expression of hLCAD in HepG2 cells is sufficient to significantly increase H₂O₂ in the presence of fatty acids. Liver mitochondria from LCAD−/− mice, but not VLCAD−/− mice, produce significantly less H₂O₂ during incubation with fatty acids. Finally, we observe highest LCAD expression in human liver, followed by kidney, lung, and pancreas. Based on our data, we propose that the presence of LCAD drives H₂O₂ formation in response to fatty acids in these tissues.

Hexanoic, Octanoic and Decanoic Acids Promote Basal and Insulin-Induced Phosphorylation of the Akt-mTOR Axis and a Balanced Lipid Metabolism in the HepG2 Hepatoma Cell Line

Metabolic illnesses such as non-alcoholic fatty liver disease (NAFLD) are in constant increase worldwide. Highly consumed long chain fatty acids (LCFA) are among the most obesogenic and steatogenic nutrients. Hepatic steatosis is associated with several complications such as insulin resistance. Growing evidence points to medium chain fatty acids (MCFA), more efficiently oxidized than LCFA, as a promising dietary alternative against NAFLD. However, reports on the hepatic effects of MCFA are sometimes conflicting. In this study we exposed HepG2 cells, a human hepatocellular model, to 0.25 mM of hexanoic (C6), or octanoic (C8), and decanoic (C10) acids separately or in a C8 + C10 equimolar mix reflecting commercially available MCFA-rich oils. We found that C6, a poorly studied MCFA, as well as C8 and C10 did not provoke the deleterious lipid anabolism runaway typically induced by LCFA palmitate. MCFA tended, instead, to promote a balanced metabolic profile and were generally non-cytotoxic. Accordingly, mitochondrial integrity was mostly preserved following MCFA treatment. However, treatments with C8 induced a mitochondrial membrane potential decrease, suggesting prolonged exposure to this lipid could be problematic. Finally, MCFA treatments maintained optimal insulin sensitivity and even fostered basal and insulin-dependent phosphorylation of the Akt-mTOR pathway. Overall, MCFA could constitute an effective nutritional tool to manage liver steatosis and hepatic insulin resistance.

Identification of key genes in non‑alcoholic fatty liver disease progression based on bioinformatics analysis

Due to economic development and lifestyle changes, the incidence of non-alcoholic fatty liver disease (NAFLD) has gradually increased in recent years. However, the pathogenesis of NAFLD is not yet fully understood. To identify candidate genes that contribute to the development and progression of NAFLD, two microarray datasets were downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified and functional enrichment analyses were performed. A protein-protein interaction network was constructed and modules were extracted using the Search Tool for the Retrieval of Interacting Genes and Cytoscape. The enriched functions and pathways of the DEGs included ‘cellular macromolecule biosynthetic process’, ‘cellular response to chemical stimulus’, ‘extracellular matrix organization’, ‘metabolic pathways’, ‘insulin resistance’ and ‘forkhead box protein O1 signaling pathway’. The DEGs, including type-1 angiotensin II receptor, formin-binding protein 1-like, RNA-binding protein with serine-rich domain 1, Ras-related C3 botulinum toxin substrate 1 and polyubiquitin-C, were identified using multiple bioinformatics methods and validated in vitro with reverse transcription-quantitative polymerase chain reaction analysis. In conclusion, five hub genes were identified in the present study, and they may aid in understanding of the molecular mechanisms underlying the development and progression of NAFLD.

Increasing Dietary Medium-Chain Fatty Acid Ratio Mitigates High-fat Diet-Induced Non-Alcoholic Steatohepatitis by Regulating Autophagy

Previous studies have demonstrated that saturated fatty acids (SFAs) are more lipotoxic than unsaturated fatty acids (UFAs) in inhibiting hepatic autophagy and promoting non-alcoholic steatohepatitis (NASH). However, there have been few studies have investigated the effects of carbon chain length on SFA-induced autophagy impairment and lipotoxicity. To investigate whether SFAs with shorter carbon chain lengths have differential effects on hepatic autophagy and NASH development, we partially replaced lard with coconut oil to elevate the ratio of medium-chain fatty acids (MCFAs) to long-chain fatty acids (LCFAs) in a mouse high-fat diet (HFD) and fed mice for 16 weeks. In addition, we treated HepG2 cells with different combinations of fatty acids to study the mechanisms of MCFAs-mediated hepatic protections. Our results showed that increasing dietary MCFA/LCFA ratio mitigated HFD-induced Type 2 diabetes and NASH in mice. Importantly, we demonstrated that increased MCFA ratio exerted its protective effects by restoring Rubicon-suppressed autophagy. Our study suggests that the relative amount of LCFAs and MCFAs in the diet, in addition to the amount of SFAs, can significantly contribute to autophagy impairment and hepatic lipotoxicity. Collectively, we propose that increasing dietary MCFAs could be an alternative therapeutic and prevention strategy for Type 2 diabetes and NASH.

A RasGAP, DAB2IP, regulates lipid droplet homeostasis by serving as GAP toward RAB40C

Lipid droplet (LD) homeostasis involves activities of various RAB small GTPases. Recently, we found RAB40C was one of the RAB proteins regulating LD homeostasis. RAB40C contains a unique SOCS domain that is required for clustering of LDs. However, its precise functional role in LD homeostasis and mechanism of regulation remain largely unknown. In this study, we observed over-accumulation of LDs in cells with RAB40C deleted by Crispr-Cas9 editing. RAB40C appeared to reduce LD accumulation after long term incubation of cells with oleic acid (24 hours). Unexpectedly, we found that Ras GTPase activating protein (GAP), DAB2IP, bound to RAB40C mainly via its GAP domain and could serve as RAB40C GAP. Studies involving overexpression of DAB2IP and its GAP defective mutant and siRNA depletion of DAB2IP all confirmed that DAB2IP negatively regulated the effect of RAB40C on LD homeostasis. These results provide a novel perspective on the regulation of RAB40C and implicate various signalling pathways regulated by DAB2IP, which may play a role in LD homeostasis via RAB40C.

Subcellular co-delivery of two different site-oriented payloads for tumor therapy

Co-delivery of multiple agents via nanocarriers is of great interest in cancer therapy, but subcellular delivery to the corresponding site of action remains challenging. Here we report a smart nanovehicle which enables two different site-oriented payloads to reach their targeted organelles based on stimulus-responsive release and nucleus-targeted modification. First, all trans retinoic acid (RA) conjugated camptothecin (RA-CPT) was loaded in a polyhedral oligomericsilsesquioxane (POSS)-based core; docetaxel (DTX) was grafted on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers. The POSS core grafted with semitelechelic HPMA copolymers then self-assembled into micelles. Once internalized into the cell, the two drugs were unleashed environment-responsively, and nuclear targeted RA remarkably facilitated the nuclear transport of CPT. Compared with single drug-loaded micelles, the dual drug-loaded platform showed superior synergic cytotoxicity, which was further strengthened by the involvement of RA. The ability to induce DNA damage and apoptosis was also enhanced by nucleus-targeted modification. Finally, dual drug-loaded micelles exhibited much better in vivo tumor inhibition (87.1%) and less systemic toxicity than the combination of single drug-loaded systems or the dual drug-loaded micelles without RA. Therefore, our study provides a novel "one platform, two targets" strategy in combinatory anti-cancer therapy.

The Role of Omega-3 Polyunsaturated Fatty Acids in Stroke

Stroke is the third commonest cause of death following cardiovascular diseases and cancer. In particular, in recent years, the morbidity and mortality of stroke keep remarkable growing. However, stroke still captures people attention far less than cardiovascular diseases and cancer. Past studies have shown that oxidative stress and inflammation play crucial roles in the progress of cerebral injury induced by stroke. Evidence is accumulating that the dietary supplementation of fish oil exhibits beneficial effects on several diseases, such as cardiovascular diseases, metabolic diseases, and cancer. Omega-3 polyunsaturated fatty acids (n-3 PUFAs), the major component of fish oil, have been found against oxidative stress and inflammation in cardiovascular diseases. And the potential of n-3 PUFAs in stroke treatment is attracting more and more attention. In this review, we will review the effects of n-3 PUFAs on stroke and mainly focus on the antioxidant and anti-inflammatory effects of n-3 PUFAs.

Medium and Long Chain Fatty Acids Differentially Modulate Apoptosis and Release of Inflammatory Cytokines in Human Liver Cells

Medium chain fatty acids (MCFA) can be more easily absorbed and supply energy more rapidly than long chain fatty acids (LCFA). However, little is known about the inflammatory response by the treatment of MCFA in human liver cells. Thus this study used human liver cells (LO2) to evaluate the effects of MCFA on apoptosis and inflammatory response. Tetrazolim-based colorimetric assay and lactate dehydrogenase assay were used to measure the viability of LO2 cells, isolated spleens and liver cells from BALB/C mice. Inverted fluorescence microscopy and flow cytometry were used to assess the cell apoptosis. Activity of superoxide dismutase and malondialdehyde level were measured to determine the oxidative damage. mRNA or protein levels of classical pro-inflammatory cytokines were analyzed by quantitative real-time polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay and western blotting. The results showed that the liver cells treated with the fatty acids at 200 μM for 24 h exhibited good viability. Fatty acids induced inflammatory cytokines at transcriptional and translational levels to a lesser extent than lipopolysaccharide. LCFA (oleic acid) up-regulated tumor necrosis fator-α, monocyte chemoattractant-1 and interleukin-1β while down-regulated IL-6 and IL-8 secretion to a higher extent than MCFA in mRNA and protein levels. These findings suggested that MCFA may induce apoptosis to a less extent and exert more gentle inflammation than LCFA in human liver cells.