DEAD-box helicase 17 (DDX17) protects cardiac function by promoting mitochondrial homeostasis in heart failure.

DEAD-box helicase 17 (DDX17) is a typical member of the DEAD-box family with transcriptional cofactor activity. Although DDX17 is abundantly expressed in the myocardium, its role in heart is not fully understood. We generated cardiomyocyte-specific Ddx17-knockout mice (Ddx17-cKO), cardiomyocyte-specific Ddx17 transgenic mice (Ddx17-Tg), and various models of cardiomyocyte injury and heart failure (HF). DDX17 is downregulated in the myocardium of mouse models of heart failure and cardiomyocyte injury. Cardiomyocyte-specific knockout of Ddx17 promotes autophagic flux blockage and cardiomyocyte apoptosis, leading to progressive cardiac dysfunction, maladaptive remodeling and progression to heart failure. Restoration of DDX17 expression in cardiomyocytes protects cardiac function under pathological conditions. Further studies showed that DDX17 can bind to the transcriptional repressor B-cell lymphoma 6 (BCL6) and inhibit the expression of dynamin-related protein 1 (DRP1). When DDX17 expression is reduced, transcriptional repression of BCL6 is attenuated, leading to increased DRP1 expression and mitochondrial fission, which in turn leads to impaired mitochondrial homeostasis and heart failure. We also investigated the correlation of DDX17 expression with cardiac function and DRP1 expression in myocardial biopsy samples from patients with heart failure. These findings suggest that DDX17 protects cardiac function by promoting mitochondrial homeostasis through the BCL6-DRP1 pathway in heart failure.

Parotid metastasis of rare lung adenocarcinoma: A case report.

BACKGROUND: Lung cancer (LC) is the leading cause of malignancy-related deaths worldwide. The most common sites of metastasis include the nervous system, bone, liver, respiratory system, and adrenal glands. LC metastasis in the parotid gland is very rare, and its diagnosis presents a challenge. Here, we report a case of parotid metastasis in primary LC. CASE SUMMARY: The patient was a 74-year-old male who was discovered to have bilateral facial asymmetry inadvertently two years ago. The right earlobe was slightly swollen and without pain or numbness. Computed tomography (CT) examination showed bilateral lung space-occupying lesions. Pulmonary biopsy was performed and revealed adenocarcinoma (right-upper-lung nodule tissue). Positron emission tomography-CT examination showed: (1) Two hypermetabolic nodules in the right upper lobe of the lung, enlarged hypermetabolic lymph nodes in the right hilar and mediastinum, and malignant space-occupying lesion in the right upper lobe of the lung and possible metastasis to the right hilar and mediastinal lymph nodes; and (2) multiple hypermetabolic nodules in bilateral parotid glands. Parotid puncture biopsy was performed considering lung adenocarcinoma metastasis. Gene detection of lung biopsy specimens revealed an EGFR gene 21 exon L858R mutation. CONCLUSION: This case report highlights the challenging diagnosis of parotid metastasis in LC given its rare nature. Such lesions should be differentiated from primary tumors of the parotid gland. Simple radiological imaging is unreliable, and puncture biopsy is needed for final diagnosis of this condition.

Hemoglobin Threshold for Blood Transfusion in Young Children Hospitalized with Iron Deficiency Anemia.

Current recommendations advise against blood transfusion in hemodynamically stable children with iron deficiency anemia. In an observational study of 125 children aged 6 through 36 months, hospitalized with iron deficiency anemia, we found that hemoglobin level predicted red blood cell transfusion (area under the curve 0.8862). A hemoglobin of 39 g/L had sensitivity 92% and specificity 72% for transfusion.

2, 2-dimethylthiazolidine hydrochloride protects against experimental contrast-induced acute kidney injury via inhibition of tubular ferroptosis.

Contrast-induced acute kidney injury (CI-AKI) has become the third leading cause of AKI acquired in hospital, lacking of effective interventions. In the study, we identified the renal beneficial role of 2, 2-dimethylthiazolidine hydrochloride (DMTD), a safer compound which is readily hydrolyzed to cysteamine, in the rodent model of CI-AKI. Our data showed that administration of DMTD attenuated the impaired renal function and tubular injury induced by the contrast agent. Levels of MDA, 4-hydroxynonenal, ferrous iron and morphological signs showed that contrast agent induced ferroptosis, which could be inhibited in the DMTD group. In vitro, DMTD suppressed ferroptosis induced by ioversol in the cultured tubular cells. Treatment of DMTD upregulated glutathione (GSH) and glutathione peroxidase 4 (GPX4). Moreover, we found that DMTD promoted the ubiquitin-mediated proteasomal degradation of Keap1, and thus increased the activity of nuclear factor erythroid 2-related factor 2 (Nrf2). Mechanistically, increase of the ubiquitylation degradation of Keap1 mediates the upregulated effect of DMTD on Nrf2. Consequently, activated Nrf2/Slc7a11 results in the increase of GSH and GPX4, and therefore leads to the inhibition of ferroptosis. Herein, we imply DMTD as a potential therapeutic agent for the treatment of CI-AKI.

Corrigendum: DDX5 and DDX17-multifaceted proteins in the regulation of tumorigenesis and tumor progression.

[This corrects the article DOI: 10.3389/fonc.2022.943032.].

Atrial Fibrillation (AFIB) in the ICU: Incidence, Risk Factors, and Outcomes: The International AFIB-ICU Cohort Study.

OBJECTIVES: To assess the incidence, risk factors, and outcomes of atrial fibrillation (AF) in the ICU and to describe current practice in the management of AF. DESIGN: Multicenter, prospective, inception cohort study. SETTING: Forty-four ICUs in 12 countries in four geographical regions. SUBJECTS: Adult, acutely admitted ICU patients without a history of persistent/permanent AF or recent cardiac surgery were enrolled; inception periods were from October 2020 to June 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We included 1,423 ICU patients and analyzed 1,415 (99.4%), among whom 221 patients had 539 episodes of AF. Most (59%) episodes were diagnosed with continuous electrocardiogram monitoring. The incidence of AF was 15.6% (95% CI, 13.8-17.6), of which newly developed AF was 13.3% (11.5-15.1). A history of arterial hypertension, paroxysmal AF, sepsis, or high disease severity at ICU admission was associated with AF. Used interventions to manage AF were fluid bolus 19% (95% CI 16-23), magnesium 16% (13-20), potassium 15% (12-19), amiodarone 51% (47-55), beta-1 selective blockers 34% (30-38), calcium channel blockers 4% (2-6), digoxin 16% (12-19), and direct current cardioversion in 4% (2-6). Patients with AF had more ischemic, thromboembolic (13.6% vs 7.9%), and severe bleeding events (5.9% vs 2.1%), and higher mortality (41.2% vs 25.2%) than those without AF. The adjusted cause-specific hazard ratio for 90-day mortality by AF was 1.38 (95% CI, 0.95-1.99). CONCLUSIONS: In ICU patients, AF occurred in one of six and was associated with different conditions. AF was associated with worse outcomes while not statistically significantly associated with 90-day mortality in the adjusted analyses. We observed variations in the diagnostic and management strategies for AF.

Delphinidin induces autophagic flux blockage and apoptosis by inhibiting both multidrug resistance gene 1 and DEAD-box helicase 17 expressions in liver cancer cells.

OBJECTIVES: To investigate the function and regulatory mechanisms of delphinidin in the treatment of hepatocellular carcinoma. METHODS: HepG2 and HuH-7 cells were treated with different concentrations of delphinidin. Cell viability was analysed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The cell autophagy and autophagic flux were analysed by LC3b-green fluorescent protein (GFP)-Adv and LC3b-GFP-monomeric red fluorescent protein-Adv transfected HepG2 and HuH-7 cells, respectively. Cell apoptosis was analysed by Hoechst33342 staining, terminal deoxynucleotidyl transferase dUTP nick end labeling staining and DNA laddering. Cell autophagy, apoptosis and survival related protein expressions were detected by Western blotting. KEY FINDINGS: After treatment with different concentrations of delphinidin, the cell survival rate was significantly decreased. Delphinidin could block the autophagic flux, resulting in a significant increase in autophagosomes, and led to an increase in cell apoptosis. The combined application of delphinidin and cisplatin could promote the antitumour effect and reduce the dose of cisplatin in tumour cells. Further mechanism studies reveal that delphinidin could inhibit the multidrug resistance gene 1 (MDR1) and the tumour-promoting transcription cofactor DEAD-box helicase 17 (DDX17) expression in tumour cells. Overexpression of DDX17 could reverse delphinidin's antitumor function in tumour cells. CONCLUSIONS: Delphinidin has a strong anti-tumour effect by inducing tumour cell autophagic flux blockage and apoptosis by inhibiting of both MDR1 and DDX17 expression.

Aging and aging-related diseases: from molecular mechanisms to interventions and treatments.

Aging is a gradual and irreversible pathophysiological process. It presents with declines in tissue and cell functions and significant increases in the risks of various aging-related diseases, including neurodegenerative diseases, cardiovascular diseases, metabolic diseases, musculoskeletal diseases, and immune system diseases. Although the development of modern medicine has promoted human health and greatly extended life expectancy, with the aging of society, a variety of chronic diseases have gradually become the most important causes of disability and death in elderly individuals. Current research on aging focuses on elucidating how various endogenous and exogenous stresses (such as genomic instability, telomere dysfunction, epigenetic alterations, loss of proteostasis, compromise of autophagy, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, deregulated nutrient sensing) participate in the regulation of aging. Furthermore, thorough research on the pathogenesis of aging to identify interventions that promote health and longevity (such as caloric restriction, microbiota transplantation, and nutritional intervention) and clinical treatment methods for aging-related diseases (depletion of senescent cells, stem cell therapy, antioxidative and anti-inflammatory treatments, and hormone replacement therapy) could decrease the incidence and development of aging-related diseases and in turn promote healthy aging and longevity.

DDX5 and DDX17-multifaceted proteins in the regulation of tumorigenesis and tumor progression.

DEAD-box (DDX)5 and DDX17, which belong to the DEAD-box RNA helicase family, are nuclear and cytoplasmic shuttle proteins. These proteins are expressed in most tissues and cells and participate in the regulation of normal physiological functions; their abnormal expression is closely related to tumorigenesis and tumor progression. DDX5/DDX17 participate in almost all processes of RNA metabolism, such as the alternative splicing of mRNA, biogenesis of microRNAs (miRNAs) and ribosomes, degradation of mRNA, interaction with long noncoding RNAs (lncRNAs) and coregulation of transcriptional activity. Moreover, different posttranslational modifications, such as phosphorylation, acetylation, ubiquitination, and sumoylation, endow DDX5/DDX17 with different functions in tumorigenesis and tumor progression. Indeed, DDX5 and DDX17 also interact with multiple key tumor-promoting molecules and participate in tumorigenesis and tumor progression signaling pathways. When DDX5/DDX17 expression or their posttranslational modification is dysregulated, the normal cellular signaling network collapses, leading to many pathological states, including tumorigenesis and tumor development. This review mainly discusses the molecular structure features and biological functions of DDX5/DDX17 and their effects on tumorigenesis and tumor progression, as well as their potential clinical application for tumor treatment.

DDX17 protects hepatocytes against oleic acid/palmitic acid-induced lipid accumulation.

Hepatic lipid accumulation is an initiation factor in fatty liver disease, and promoting a reduction in hepatic lipid accumulation is an important treatment strategy. DEAD box RNA helicase 17 (DDX17) is a member of the DEAD-box family and a molecular chaperone. Previous studies have demonstrated that DDX17 is a transcriptional coregulator of tumorigenesis, inflammation, and macrophage cholesterol efflux. The liver is the main site for lipid metabolism, and metabolic (dysfunction)-associated fatty liver disease (MAFLD) is one of the most common chronic liver diseases. However, the impact of DDX17 on hepatic lipid accumulation has not been verified. In this study, we found, for the first time, that oleic acid/palmitic acid (OA/PA)-induced lipid accumulation was largely abrogated by DDX17 overexpression in both HepG2 (a human hepatocellular carcinoma line) and Hep1-6 (a murine hepatocellular carcinoma line) cells, and this effect was due to a marked reduction in cellular triglyceride (TG) content. Moreover, the overexpression of DDX17 was accompanied by a significant decrease in the expression of genes involved in de novo fatty acid synthesis (FAS, ACC, and SCD-1) in both HepG2 and Hep1-6 cells. In conclusion, DDX17 protected against OA/PA-induced lipid accumulation in hepatocytes through de novo lipogenesis inhibition.

miR-488-3p Protects Cardiomyocytes against Doxorubicin-Induced Cardiotoxicity by Inhibiting CyclinG1.

OBJECTIVE: To investigate the protective effects and regulatory mechanism of miR-488-3p on doxorubicin-induced cardiotoxicity. METHODS: The C57BL/6 mice and primary cardiomyocytes were used to construct doxorubicin-induced cardiomyocyte injury models in vivo and in vitro. The levels of miR-488-3p and its downstream target genes were analyzed by quantitative real-time PCR. Mouse cardiac function, cell survival, cellular injury-related proteins, and the apoptosis level of cardiomyocytes were analyzed by echocardiography, MTT analysis, Western blotting, and DNA laddering separately. RESULTS: Cardiomyocyte injury caused by a variety of stimuli can lead to the reduction of miR-488-3p level, especially when stimulated with doxorubicin. Doxorubicin led to significant decrease in cardiac function, cell autophagic flux blockage, and apoptosis in vivo and in vitro. The expression of miR-488-3p's target gene, CyclinG1, increased remarkably in the doxorubicin-treated neonatal mouse cardiomyocytes. Overexpression of miR-488-3p inhibited CyclinG1 expression, increased cardiomyocyte viability, and attenuated doxorubicin-induced cardiomyocyte autophagic flux blockage and apoptosis. CONCLUSIONS: miR-488-3p is one of the important protective miRNAs in doxorubicin-induced cardiotoxicity by inhibiting the expression of CyclinG1, which provides insight into the possible clinical application of miR-488-3p/CyclinG1 as therapeutic targets in doxorubicin-induced cardiovascular diseases.

Lysophosphatidylcholine disrupts cell adhesion and induces anoikis in hepatocytes.

Lysophosphatidylcholine (LPC), the active metabolite of palmitate, triggers hepatocyte death by activating endoplasmic reticulum stress and JNK signalling-mediated lipoapoptosis. However, LPC-induced cytotoxicity in hepatocytes is not well understood. Here, we found for the first time that LPC-induced cell rounding occurred prior to apoptosis. LPC-induced rounding of cells reduced both cell-extracellular matrix (ECM) adhesion and cell-cell junctions, which promoted detachment-induced apoptosis (defined as anoikis) in hepatocytes. Further study revealed that LPC altered cellular morphology and cell adhesion by inhibiting integrin and cadherin signalling-mediated microfilament polymerization. We also found that ECM supplementation and microfilament cytoskeletal stabilization inhibited LPC-induced hepatocyte death by attenuating anoikis. Our data indicate a novel cytotoxic process and signalling pathway induced by LPC.

Bone marrow macrophage-derived exosomal miR-143-5p contributes to insulin resistance in hepatocytes by repressing MKP5.

OBJECTIVE: In this study, we aim to explore the role of bone marrow macrophage-derived exosomes in hepatic insulin resistance, investigate the substance in exosomes that regulates hepatic insulin signalling pathways, reveal the specific molecular mechanisms involved in hepatic insulin resistance and further explore the role of exosomes in type 2 diabetes. MATERIALS AND METHODS: High-fat diet (HFD)-fed mice were used as obesity-induced hepatic insulin resistance model, exosomes were isolated from BMMs which were extracted from HFD-fed mice by ultracentrifugation. Exosomes were analysed the spectral changes of microRNA expression using a microRNA array. The activation of the insulin signalling pathway and the level of glycogenesis were examined in hepatocytes after transfected with miR-143-5p mimics. Luciferase assay and western blot were used to assess the target of miR-143-5p. RESULTS: BMMs from HFD-fed mice were polarized towards M1, and miR-143-5p was significantly upregulated in exosomes of BMMs from HFD-fed mice. Overexpression of miR-143-5p in Hep1-6 cells led to decreased phosphorylation of AKT and GSK and glycogen synthesis. Dual-luciferase reporter assay and western blot demonstrated that mitogen-activated protein kinase phosphatase-5 (Mkp5, also known as Dusp10) was the target gene of miR-143-5p. Moreover, the overexpression of MKP5 could rescue the insulin resistance induced by transfection miR-143-5p mimics in Hep1-6. CONCLUSION: Bone marrow macrophage-derived exosomal miR-143-5p induces insulin resistance in hepatocytes through repressing MKP5.

Protein Phosphatase 4 Promotes Hepatocyte Lipoapoptosis by Regulating RAC1/MLK3/JNK Pathway.

Lipotoxicity-induced apoptosis, also referred to as lipoapoptosis, is one of the important initial factors promoting the progression from hepatosteatosis to nonalcoholic steatohepatitis (NASH). Saturated free fatty acids (SFAs), which are increased significantly in NASH, are directly hepatotoxic which induce hepatocyte lipoapoptosis. Previously, we reported that protein phosphatase 4 (PP4) was a novel regulator of hepatic insulin resistance and lipid metabolism, but its role in hepatic lipoapoptosis remains unexplored. In this study, we found out that PP4 was upregulated in the livers of western diet-fed-induced NASH mice and SFA-treated murine primary hepatocytes and HepG2 cells. In addition, we found for the first time that suppression of PP4 decreased SFA-induced JNK activation and expression of key modulators of hepatocyte lipoapoptosis including p53-upregulated modulator of apoptosis (PUMA) and Bcl-2-interacting mediator (Bim) and reduced hepatocyte lipoapoptosis level as well both in vitro and in vivo. Further study revealed that PP4 induced JNK activation and lipoapoptosis-related protein expression by regulating the RAC1/MLK3 pathway instead of the PERK/CHOP pathway. The effects of palmitate-treated and PP4-induced lipoapoptosis pathway activation were largely abolished by RAC1 inhibition. Moreover, we identified that PP4 interacted with RAC1 and regulated GTPase activity of RAC1. In conclusion, these results demonstrated that PP4 was a novel regulator of hepatocyte lipoapoptosis and mediated hepatocyte lipoapoptosis by regulating the RAC1/MLK3/JNK signaling pathway. Our finding provided new insights into the mechanisms of this process.

Polypeptide Globular Adiponectin Ameliorates Hypoxia/Reoxygenation-Induced Cardiomyocyte Injury by Inhibiting Both Apoptosis and Necroptosis.

Adiponectin is a small peptide secreted and a key component of the endocrine system and immune system. Although globular adiponectin protects myocardial ischemia/reperfusion-induced cardiomyocyte injury, the protective mechanisms remain largely unresolved. Using a neonatal rat ventricular myocyte hypoxia/reoxygenation model, we investigated the role of its potential mechanisms of necroptosis in globular adiponectin-mediated protection in hypoxia/reoxygenation-induced cardiomyocyte injury as compared to apoptosis. We found that globular adiponectin treatment attenuated cardiomyocyte injury as indicated by increased cell viability and reduced lactate dehydrogenase release following hypoxia/reoxygenation. Immunofluorescence staining and Western blotting demonstrated that both necroptosis and apoptosis were triggered by hypoxia/reoxygenation and diminished by globular adiponectin. Necrostatin-1 (RIP1-specific inhibitor) and Z-VAD-FMK (pan-caspase inhibitor) only mimicked the inhibition of necroptosis and apoptosis, respectively, by globular adiponectin in hypoxia/reoxygenation-treated cardiomyocytes. Globular adiponectin attenuated reactive oxygen species production, oxidative damage, and p38MAPK and NF-κB signaling, all important for necroptosis and apoptosis. Collectively, our study suggests that globular adiponectin inhibits hypoxia/reoxygenation-induced necroptosis and apoptosis in cardiomyocytes probably by reducing oxidative stress and interrupting p38MAPK signaling.

GPR120 facilitates cholesterol efflux in macrophages through activation of AMPK signaling pathway.

Cholesterol efflux from macrophages is the initial step of reverse cholesterol transport, an important process for high-density lipoprotein-mediated atheroprotection. G protein-coupled receptor (GPR) 120, which functions as long-chain fatty acid receptor, is well known for its anti-inflammatory and insulin-sensitizing function in macrophages. However, the role of GPR120 on macrophage foam cell formation, the hallmark of atherosclerotic plaques, has not been verified. In this study, we found for the first time that stimulation of GPR120 by its agonist GW9508 elevated the expression of ATP-binding cassette transporters (ABC) A1 and ABCG1 in THP-1 macrophage-derived foam cells and Raw264.7 macrophages, and promoted ABCA1- and ABCG1-mediated cholesterol efflux and reduced cellular cholesteryl ester (CE) content as well. In addition, GPR120 activation was accompanied with the stimulation of AMPK pathway in macrophages; however, the effect of GPR120 on macrophage cholesterol efflux was largely abolished by AMPK inhibition. Moreover, the AMPK activity and the expression of ABCA1 and ABCG1 were markedly abrogated by knockdown of GPR120, or application of phospholipase C (PLC) inhibitor, calcium chelator, or CaMKK inhibitor. Because only free cholesterol can be effluxed from macrophages, we found that activation of AMPK could lead to increase both neutral CEs hydrolysis by upregulation of neutral cholesterol ester hydrolase expression and acid CEs hydrolysis by activation of ULK1. In conclusion, these results demonstrated that GPR120 facilitated ABCA1- and ABCG1-mediated cholesterol efflux through activation of PLC/Ca2+ /CaMKK/AMPK signaling pathway, which induced CE hydrolysis and elevated the expression of ABCA1 and ABCG1 in macrophages.

Dexrazoxane Protects Cardiomyocyte from Doxorubicin-Induced Apoptosis by Modulating miR-17-5p.

The usage of doxorubicin is hampered by its life-threatening cardiotoxicity in clinical practice. Dexrazoxane is the only cardioprotective medicine approved by the FDA for preventing doxorubicin-induced cardiac toxicity. Nevertheless, the mechanism of dexrazoxane is incompletely understood. The aim of our study is to investigate the possible molecular mechanism of dexrazoxane against doxorubicin-induced cardiotoxicity. We established a doxorubicin-induced mouse and cardiomyocyte injury model. Male C57BL/6J mice were randomly distributed into a control group (Con), a doxorubicin treatment group (DOX), a doxorubicin plus dexrazoxane treatment group (DOX+DEX), and a dexrazoxane treatment group (DEX). Echocardiography and histology analyses were performed to evaluate heart function and structure. DNA laddering, qRT-PCR, and Western blot were performed on DOX-treated cardiomyocytes with/without DEX treatment in vitro. Cardiomyocytes were then transfected with miR-17-5p mimics or inhibitors in order to analyze its downstream target. Our results demonstrated that dexrazoxane has a potent effect on preventing cardiac injury induced by doxorubicin in vivo and in vitro by reducing cardiomyocyte apoptosis. MicroRNA plays an important role in cardiovascular diseases. Our data revealed that dexrazoxane could upregulate the expression of miR-17-5p, which plays a cytoprotective role in response to hypoxia by regulating cell apoptosis. Furthermore, the miRNA and protein analysis revealed that miR-17-5p significantly attenuated phosphatase and tensin homolog (PTEN) expression in cardiomyocytes exposed to doxorubicin. Taken together, dexrazoxane might exert a cardioprotective effect against doxorubicin-induced cardiomyocyte apoptosis by regulating the expression of miR-17-5p/PTEN cascade.

miR­338­3p mediates gluconeogenesis via targeting of PP4R1 in hepatocytes.

Hyperglycaemia is a characteristic of type 2 diabetes. In hepatocytes, impaired insulin sensitivity leads to increased gluconeogenesis and decreased glycogenesis. MicroRNA (miR)­338­3p is associated with tumour necrosis factor (TNF)­α­induced suppression of hepatic glycogenesis via regulation of protein phosphatase 4 regulatory subunit 1 (PP4R1). However, the effect of miR­338­3p on gluconeogenesis in hepatocytes remains unknown. In a previous study, it was demonstrated that miR­338­3p is downregulated in the livers of mice and in mouse HEPA1­6 hepatocytes following treatment with TNF­α. In the present study, the effect of miR­338­3p on TNF­α­induced gluconeogenesis in hepatocytes was investigated. The levels of phosphorylated­FOXO1/FOXO1, phosphoenolpyruvate carboxykinase (PEPCK), peroxisome proliferator­activated receptor γ coactivator (PGC­1α) and glucose­6­phosphatase (G6Pase) were measured by western blotting. The mRNA levels of PEPCK, PGC­1α and G6Pase were determined by quantitative polymerase chain reaction. Pyruvate tolerance testing was used to determine the gluconeogenesis of mouse livers. The results demonstrated that treatment with TNF­α resulted in increased levels of gluconeogenesis in the livers of mice and decreased miR­338­3p expression levels in HEPA1­6 cells. Overexpression of miR­338­3p reversed TNF­α­induced glucose production via enhancement of phosphorylated forkhead box O1 levels and downregulation of the expression levels of genes associated with gluconeogenesis, including peroxisome proliferator­activated receptor γ coactivator­1α, phosphoenolpyruvate carboxykinase and glucose­6­phosphatase. However, inhibition of miR­338­3p expression was revealed to enhance gluconeogenesis in the livers of mice and in HEPA1­6 cells. Furthermore, downregulation of PP4R1 was revealed to attenuate the effect on glucose production following treatment with miR­338­3p inhibitors. In conclusion, the results of the present study revealed that miR­338­3p may be involved in TNF­α­mediated gluconeogenesis via targeting of PP4R1 in hepatocytes.

Inhibition of Poly(ADP-Ribose) Polymerase Increased Lipid Accumulation Through SREBP1 Modulation.

BACKGROUND/AIMS: Excess energy intake leads to metabolic dysfunction, accompanied by oxidative stress and poly(ADP-ribose) polymerase (PARP) activation. METHODS: To determine the role of PARP activation in the incidence of metabolic dysfunction, PJ34, the PARP inhibitor, was administered to the oleic acid-treated hepatoma cells and high-fat diet-fed mice. The expression of genes was detected by quantitative real-time PCR and western blotting. Lipid droplets in the cells and tissues were stained with Oil Red O. RESULTS: PJ34 treatment aggravated oleic acid-induced lipid accumulation in hepatoma cells and induced SREBP1 expression by modulating the modification of transcription factor specificity protein 1 (Sp1). The high-fat diet-mice exhibited hyperglycemia, insulin resistance and lipid accumulation after 3 months of feeding. Although the serum level of lipid was not altered after PJ34 treatment, the expression level of lipogenic gene was up-regulated and the lipid accumulation was increased in the liver tissues of high-fat diet + PJ34-treated mice. In the high-fat diet + PJ34-treated mice, the insulin sensitivity was slightly changed and the levels of blood glucose and serum insulin were decreased compared with the mice fed with a high-fat diet alone. CONCLUSION: Taken together, PARP inhibition up-regulated the expression level of lipogenic gene and significantly induced lipid accumulation in the liver, which might worsen lipid metabolism disorders. These data will guide future research into the application of PARP inhibitors in the management of metabolic diseases.

miR-291b-3p mediated ROS-induced endothelial cell dysfunction by targeting HUR.

Endothelial dysfunction is an early marker of atherosclerosis. Previous studies have indicated that microRNA (miR)­291b­3p regulates the metabolism of lipids and glucose in the liver via targeting adenosine monophosphate­activated kinase α1 and transcription factor p65. The present study investigated whether miR­291b­3p mediated H2O2­mediated endothelial dysfunction. The level of apoptosis of EOMA mouse endothelial cells was analyzed by terminal deoxynucleotidyl­transferase­mediated dUTP nick end labelling staining. The mRNA levels of miR­291b­3p, intercellular adhesion molecule­1 (ICAM­1) and vascular adhesion molecule­1 (VCAM­1) were determined by quantitative polymerase chain reaction. The level of phosphorylated extracellular signal­regulated kinase, and levels of B­cell lymphoma 2 (Bcl­2)­associated X protein and Bcl­2 protein were detected by western blot analysis. The treatment of H2O2 induced the apoptosis and increased the mRNA levels of miR­291b­3p, ICAM­1 and VCAM­1 in EOMA cells. It was also demonstrated that the overexpression of miR­291b­3p promoted EOMA cell apoptosis and dysfunction. In contrast, the downregulation of miR­291b­3p rescued the effect of H2O2 on EOMA cell dysfunction. In addition, Hu antigen R (HuR) was identified as a target gene of miR­291b­3p in EOMA cells. The overexpression of HuR reversed the endothelial dysfunction induced by miR­291b­3p mimics. The present study provides novel insight into the critical role of miR­291b­3p on the endothelial dysfunction induced by H2O2. miR­291b­3p may mediate H2O2­induced endothelial dysfunction via targeting HuR.