What is the impact of ferroptosis on diabetic cardiomyopathy: a systematic review.

Iron overload increases the production of harmful reactive oxygen species in the Fenton reaction, which causes oxidative stress in the body and lipid peroxidation in the cell membrane, and eventually leads to ferroptosis. Diabetes is associated with increased intracellular oxidative stress, inflammation, autophagy, microRNA alterations, and advanced glycation end products (AGEs), which cause cardiac remodeling and cardiac diastolic contractile dysfunction, leading to the development of diabetic cardiomyopathy (DCM). While these factors are also closely associated with ferroptosis, more and more studies have shown that iron-mediated ferroptosis is an important causative factor in DCM. In order to gain fresh insights into the functions of ferroptosis in DCM, this review methodically summarizes the traits and mechanisms connected with ferroptosis and DCM.

UFMylation of HRD1 regulates endoplasmic reticulum homeostasis.

Ubiquitin fold modifier 1 is a small ubiquitin-like protein modifier that is essential for embryonic development of metazoans. Although UFMylation has been connected to endoplasmic reticulum homeostasis, the underlying mechanisms and the relevant cellular targets are largely unknown. Here, we show that HRD1, a ubiquitin ligase of ER-associated protein degradation (ERAD), is a novel substrate of UFM1 conjugation. HRD1 interacts with UFMylation components UFL1 and DDRGK1 and is UFMylated at Lys610 residue. In UFL1-depleted cells, the stability of HRD1 is increased and its ubiquitination modification is reduced. In the event of ER stress, the UFMylation and ubiquitination modification of HRD1 is gradually inhibited over time. Alteration of HRD1 Lys610 residue to arginine impairs its ability to degrade unfolded or misfolded proteins to disturb protein processing in ER. These results suggest that UFMylation of HRD1 facilitates ERAD function to maintain ER homeostasis.

Unraveling the roles of endoplasmic reticulum-associated degradation in metabolic disorders.

Misfolded proteins retained in the endoplasmic reticulum cause many human diseases. ER-associated degradation (ERAD) is one of the protein quality and quantity control system located at ER, which is responsible for translocating the misfolded proteins or properly folded but excess proteins out of the ER for proteasomal degradation. Recent studies have revealed that mice with ERAD deficiency in specific cell types exhibit impaired metabolism homeostasis and metabolic diseases. Here, we highlight the ERAD physiological functions in metabolic disorders in a substrate-dependent and cell type-specific manner.

Association between Intestinal Microecological Changes and Atherothrombosis.

Atherosclerosis (AS) is a chronic inflammatory disease of large- and medium-sized arteries that causes ischemic heart disease, strokes, and peripheral vascular disease, collectively called cardiovascular disease (CVD), and is the leading cause of CVD resulting in a high rate of mortality in the population. AS is pathological by plaque development, which is caused by lipid infiltration in the vessel wall, endothelial dysfunction, and chronic low-grade inflammation. Recently, more and more scholars have paid attention to the importance of intestinal microecological disorders in the occurrence and development of AS. Intestinal G-bacterial cell wall lipopolysaccharide (LPS) and bacterial metabolites, such as oxidized trimethylamine (TMAO) and short-chain fatty acids (SCFAs), are involved in the development of AS by affecting the inflammatory response, lipid metabolism, and blood pressure regulation of the body. Additionally, intestinal microecology promotes the progression of AS by interfering with the normal bile acid metabolism of the body. In this review, we summarize the research on the correlation between maintaining a dynamic balance of intestinal microecology and AS, which may be potentially helpful for the treatment of AS.

Cardioprotective and anti-inflammatory effects of Caveolin 1 in experimental diabetic cardiomyopathy.

Previous studies of the Caveolin 1 (Cav1) protein and caveolae, which are lipid raft structures found on the plasma membranes of certain cells, are associated with fat metabolism disorders, inflammation, diabetes, and cardiovascular disease. However, there have been no reports linking Cav1 to diabetic cardiomyopathy (DCM). In the present study, we established a relationship between Cav1 and the development of DCM. We found that compared with Cav1+/+ mice, Cav1-/- diabetic mice exhibited more severe cardiac injury, increased activation of NF-κB signaling, and up-regulation of downstream genes, including hypertrophic factors and inflammatory fibrosis factors in heart tissues. Additionally, in vitro results showed that knocking down Cav1 further activated HG-induced NF-κB signaling, increased the expression of downstream target genes, and decreased the expression of inhibitor α of NF-κB (iκBα), all of which have been linked to DCM pathogenesis. In contrast, Cav1 overexpression resulted in the opposite effects. Our study suggests that Cav1 knockdown promotes cardiac injury in DCM by activating the NF-κB signaling pathway, and targeting Cav1 may lead to the development of novel treatments for DCM.

The effects of different stress on intestinal mucosal barrier and intestinal microecology were discussed based on three typical animal models.

Recent studies have revealed that the effect of intestinal microecological disorders on organismal physiology is not limited to the digestive system, which provides new perspectives for microecological studies and new ideas for clinical diagnosis and prevention of microecology-related diseases. Stress triggers impairment of intestinal mucosal barrier function, which could be duplicated by animal models. In this paper, pathological animal models with high prevalence and typical stressors-corresponding to three major stressors of external environmental factors, internal environmental factors, and social psychological factors, respectively exemplified by burns, intestinal ischemia-reperfusion injury (IIRI), and depression models-were selected. We summarized the construction and evaluation of these typical animal models and the effects of stress on the organism and intestinal barrier, as well as systematically discussed the effects of different stresses on the intestinal mucosal barrier and intestinal microecology.

High expression of SGK1 in thrombosis of acute ST-segment elevation myocardial infarction: Based on proteomics analysis of intracoronary thrombosis.

INTRODUCTION AND OBJECTIVES: Thrombosis is involved in the onset and progression of ST-segment elevation myocardial infarction (STEMI). The aim of this study was to explore the expression level of serum- and glucocorticoid-inducible kinase 1 (SGK1) in intracoronary thrombus and the relationship between them. METHODS: We identified 30 patients who received treatment in the Affiliated Hospital of Hangzhou Normal University between May 2018 to May 2020 and who underwent thrombus aspiration and percutaneous coronary intervention for ST-segment-elevation myocardial infarction. Additionally, we selected 30 patients with normal coronary angiography for the control group. We analyzed thrombus protein expression profiling by combining tandem mass tag labeling, high-performance liquid chromatography fractionation and mass spectrometry quantification approach. RESULTS: The differentially regulated protein profiles revealed the alteration of serine-threonine/tyrosine-protein kinase, which was upregulated significantly in the experimental group. We selected SGK1 downstream factor for validation and found that the expression of SGK1 in the thrombus of STEMI was significantly increased. Immunohistochemistry (IHC) showed significantly increased expression of SGK1 in the thrombus of STEMI patients compared with the control group (17.21±2.36 vs. 4.14±1.17%, p<0.05). Similar findings were observed in the Western blot analysis (p<0.05). IHC showed that SGK1 expressed in a region similar to that of the platelets. CONCLUSION: This is the first quantitative proteomics study to assess thrombus in patients with STEMI. The expression of SGK1 in thrombus was significantly higher in patients with acute STEMI than in the control group. SGK1 might be involved in the platelet physiological process.

Efficacy and safety of left atrial appendage occlusion in atrial fibrillation patients with chronic kidney disease: a systematic review and meta-analysis.

Atrial fibrillation (AF) is the most common arrhythmia among the elderly, and more frequently occur in those with chronic kidney disease (CKD). Left atrial appendage occlusion (LAAO) is used as a mechanical alternative approach for prevention of AF-related thromboembolisms. This meta-analysis was conducted to provide suggestions for the clinical application of LAAO in AF patients with CKD. The incidence of perioperative adverse events and other clinical effects after operation was by a single rate meta-analysis. Results showed that incidence of adverse events in the perioperative period after LAAO was generally low, with only pericardial effusion / tamponade (1.90%) and mortality rate (1.10%). During the follow-up period, the incidence of stroke/transient ischemic attack (TIA) and bleeding were 2.17% and 4.53%, respectively. A low incidence rate of adverse events was found in the perioperative period following LAAO. These results indicate that LAAO more effectively prevents the occurrence of stroke/TIA and minimizes bleeding events than oral anticoagulants.

Pathophysiologic Role of Molecules Determining Arteriovenous Differentiation in Adult Life.

The structural differences between arteries and veins are genetically predetermined. Vascular identity markers, the molecular markers specific to veins and arteries, determine the differential development of vessels during embryogenesis and their expression persists in adult vessels. It is revealed that they can be reactivated under various pathophysiologic conditions even after vessel differentiation. Thus, once considered as quiescent in adults, vascular identity markers may actually play significant roles in vascular remodeling. Manipulation of vascular identity and the underlying molecular mechanisms might be a novel strategy to improve vascular remodeling for clinical application.

Pyruvate dehydrogenase activation precedes the down-regulation of fatty acid oxidation in monocrotaline-induced myocardial toxicity in mice.

Fatty acid (FA) oxidation is impaired and glycolysis is promoted in the damaged heart. However, the factor(s) in the early stages of myocardial metabolic impairment remain(s) unclear. C57B6 mice were subcutaneously administered monocrotaline (MCT) in doses of 0.3 mg/g body weight twice a week for 3 or 6 weeks. Right and left ventricles at 3 and 6 weeks after administration were subjected to capillary electrophoresis-mass spectrometry metabolomic analysis. We also examined mRNA and protein levels of key metabolic molecules. Although no evidence of PH and right ventricular failure was found in the MCT-administered mice by echocardiographic and histological analyzes, the expression levels of stress markers such as TNFα and IL-6 were increased in right and left ventricles even at 3 weeks, suggesting that there was myocardial damage. Metabolites in the tricarboxylic acid (TCA) cycle were decreased and those in glycolysis were increased at 6 weeks. The expression levels of FA oxidation-related factors were decreased at 6 weeks. The phosphorylation level of pyruvate dehydrogenase (PDH) was significantly decreased at 3 weeks. FA oxidation and the TCA cycle were down-regulated, whereas glycolysis was partially up-regulated by MCT-induced myocardial damage. PDH activation preceded these alterations, suggesting that PDH activation is one of the earliest events to compensate for a subtle metabolic impairment from myocardial damage.

Distinct Vascular Remodeling Pattern of Adult Rats with Carotid-Jugular Shunt.

BACKGROUND: Previous research has revealed that patent vein grafts lose their venous identity Eph-B4 but do not gain arterial identity ephrin-B2 during adaptation to the arterial circulation, and vascular identity marker, for example, the Eph-B4 signaling is a critical determinant of venous wall thickness of vein grafts. But what is the remodeling pattern, especially the remodeling pattern of vascular identity in the venous segment of arteriovenous shunt at a late stage postoperation has not been fully explored. This study was conducted to characterize the remodeling pattern of shear stress, vascular identity, structural composition and morphology, and transcriptional profiles in jugular segment of carotid-jugular (CJ) shunt and/or pulmonary artery (PA), which delivers an increased amount of mixed blood at a late stage postoperation in adult rats. METHODS: CJ shunt was created in adult Wistar rats via end-to-end anastomosis of carotid artery (CA) and jugular vein (JV). At the time of 15 weeks, after hemodynamics test, remodeled jugular segment of CJ shunt, PA, and sham-operated corresponding vessels were isolated. Reverse transcription polymerase chain reaction, microarray, western blot, immunohistochemistry experiments, and morphology analyses were performed. RESULTS: CJ shunt shear stresses have been patterned to some sort of balance with no significant difference in shear stress between carotid segment and jugular segment (P > 0.05). Immunohistochemical analysis reveals that venous identity marker Eph-B4 is lost, but arterial identity markers ephrin-B2 and regulator of G-protein signaling 5 are gained in jugular segment of CJ shunt (P < 0.01), and these 2 arterial identity markers further strengthened in PA (P < 0.01) in shunted rats compared with controls. Jugular segment of CJ shunt undergoes significant intimal hyperplasia with strong expression of smooth muscle cell markers (P < 0.05) and demonstrates a distinct transcriptional profiles which reveals that transcripts of 5 arterial markers are significantly upregulated (P < 0.05 or < 0.01) compared with sham-operated JV; among them, G-protein signaling 5 is exactly the gene with the largest fold change (10.14-fold) in all genes tested by microarray experiment. CONCLUSIONS: Venous identity is lost, but arterial identity is gained in jugular segment of CJ shunt and arterial identity further strengthened in PA in adult shunted rats during late adaptation.

New mouse model of skeletal muscle atrophy using spiral wire immobilization.

INTRODUCTION: Disuse-induced skeletal muscle atrophy is a serious concern; however, there is not an effective mouse model to elucidate the molecular mechanisms. We developed a noninvasive atrophy model in mice. METHODS: After the ankle joints of mice were bandaged into a bilateral plantar flexed position, either bilateral or unilateral hindlimbs were immobilized by wrapping in bonsai steel wire. RESULTS: After 3, 5, or 10 days of immobilization of the hip, knee, and ankle, the weight of the soleus and plantaris muscles decreased significantly in both bilateral and unilateral immobilization. MAFbx/atrogin-1 and MuRF1 mRNA was found to have significantly increased in both muscles, consistent with disuse-induced atrophy. Notably, the procedure did not result in either edema or necrosis in the fixed hindlimbs. CONCLUSIONS: This method allows repeated, direct access to the immobilized muscle, making it a useful procedure for concurrent application and assessment of various therapeutic interventions. Muscle Nerve 54: 788-791, 2016.

Inducing Specific Immune Tolerance to Prevent Type 1 Diabetes in NOD Mice.

OBJECTIVES: Proinsulin is the first autoantigen in type 1 diabetes (T1D). We reasoned that coupling hematopoietic stem cells (HSCs) transplantation with ex vivo transduction of syngeneic HSCs with lentiviral vectors to express proinsulin II could prevent T1D in nonobese diabetic (NOD) mice. METHODS: Hematopoietic stem cells were isolated from 6- to 8-week-old NOD female mice and transduced in vitro with lentiviral vectors encoding proinsulin II. Preconditioned 3- to 4-week-old female NOD mice were transplanted with transduced or nontransduced HSCs and compared with age-matched unmanipulated control. The insulitis, T1D development, and immune reconstitution were assessed. RESULTS: The mean (SD) insulitis score was significantly reduced (1.156 [0.575] vs 2.156 [0.892] or 3.043 [0.728], P = 0.009 or <0.001), and diabetes was nearly completely prevented (1/13 vs 5/12 or 4/9, P = 0.031 or 0.013) in recipients of transduced HSCs expressing proinsulin II as compared with recipients of nontransduced HSCs or unmanipulated control. Sialitis, reconstitution of peripheral blood leukocytes, and in vitro recall responses to ovalbumin were not different between 3 groups of mice. CONCLUSIONS: Syngeneic transplantation of HSCs transduced ex vivo with lentiviral vectors to encode proinsulin II is a novel strategy to prevent T1D.

Heterozygous deletion of sarcolipin maintains normal cardiac function.

Sarcolipin (SLN) is a small proteolipid and a regulator of sarco(endo)plasmic reticulum Ca(2+)-ATPase. In heart tissue, SLN is exclusively expressed in the atrium. Previously, we inserted Cre recombinase into the endogenous SLN locus by homologous recombination and succeeded in generating SLN-Cre knockin (Sln(Cre/+)) mice. This Sln(Cre/+) mouse can be used to generate an atrium-specific gene-targeting mutant, and it is based on the Cre-loxP system. In the present study, we used adult Sln(Cre/+) mice atria and analyzed the effects of heterozygous SLN deletion by Cre knockin before use as the gene targeting mouse. Both SLN mRNA and protein levels were decreased in Sln(Cre/+) mouse atria, but there were no morphological, physiological, or molecular biological abnormalities. The properties of contractility and Ca(2+) handling were similar to wild-type (WT) mice, and expression levels of several stress markers and sarcoplasmic reticulum-related protein levels were not different between Sln(Cre/+) and WT mice. Moreover, there was no significant difference in sarco(endo)plasmic reticulum Ca(2+)-ATPase activity between the two groups. We showed that Sln(Cre/+) mice were not significantly different from WT mice in all aspects that were examined. The present study provides basic characteristics of Sln(Cre/+) mice and possibly information on the usefulness of Sln(Cre/+) mice as an atrium-specific gene-targeting model.

Effect of inflammatory factor-induced cyclo-oxygenase expression on the development of reperfusion-related no-reflow phenomenon in acute myocardial infarction.

No reflow after reperfusion therapy for myocardial infarction is a strong predictor of clinical outcome. Increased levels of inflammatory factors, including C-reactive protein (CRP), in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI) may affect myocardial perfusion. However, why the no-reflow phenomenon increases in inflammation stress after PCI is not clear. The aim of the present study was to determine the effects and molecular mechanisms underlying the effects of CRP on the expression of cyclo-oxygenase (COX) on the development of the no-reflow phenomenon. There was a significant increase in plasma levels of CRP and interleukin (IL)-6 in no-reflow patients, suggesting that inflammatory factors play an important role in the development of the no-reflow phenomenon. The mechanisms involved were further evaluated after reperfusion in a rat model mimicking the no-reflow phenomenon. Compared with normal reflow rats, there were significant increases in both COX-1 and COX-2 in cardiac tissue from no-reflow rats. The COX inhibitor indomethacin (5 mg/kg, i.p.) significantly reduced the no-reflow area. In another series of experiments, human coronary artery endothelial cells (HCAEC) were treated with CRP at clinically relevant concentrations (5-25 µg/mL). C-Reactive protein significantly increased COX-1 and COX-2 levels in a time- and concentration-dependent manner. In addition, extracellular signal-regulated kinase (ERK) and Jun N-terminal kinase (JNK) were activated in CRP (5, 10, 25 µg/mL)-treated HCAEC cultures. Furthermore, the ERK inhibitor pd98059 (30 µmol/L) and the JNK inhibitor sp600125 (10 µmol/L) blocked CRP-induced COX-1 and COX-2 expression for 12 h. Together, the findings of the present study suggest that CRP can promote the development of the no-reflow phenomenon by increasing COX-1 and COX-2 expression, which is regulated, in part, via ERK and JNK activity.

[Development and evaluation of a high-fat/high-fructose diet-induced nonalcoholic steatohepatitis mouse model].

OBJECTIVE: To develop and evaluate a mouse model of nonalcoholic steatohepatitis (NASH) induced by a high-fat and high-fructose (HFHFr) diet. METHODS: Six-week-old C3H mice were randomly divided into groups for HFHFr diet experimental modeling, high fat-only (HF) diet controls, high fructose-only (HFr) diet controls, and standard chow (SC) diet controls. The standard HFHFr diet was modified so that it consisted of 76.5% standard chow, 12% lard, 1% cholesterol, 5% egg yolk powder, 5% whole milk powder, and 0.5% sodium cholate, along with 20% fructose drinking water. At the end of experimental weeks 4, 8, and 16, measurements were taken for the NASH-related parameters of body mass, serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), lipid profile, and wet liver weight (upon sacrifice). In addition, histological changes in the liver were evaluated by hematoxylin-eosin (HE) and oil red O staining. The significance of differences between groups was assessed by statistical analysis, using the METHODS: of t-test, Wilcoxon rank sum test, x2 test, F test or Fisher's test as appropriate. RESULTS: As compared to the mice in the SC group at the corresponding time points, the mice in the HFHFr and HF groups showed significantly higher body mass and wet liver weight, as well as more extensive and robust lipid disposition in hepatic tissues as evidenced by oil red O staining. However, HE staining indicated that the HFHFr and HF groups had different degrees of macrosteatosis accompanied with intralobular inflammatory foci, with the former showing more remarkable NASH-related histological changes. Analysis at the end of week 16 showed that about 80% of the mice in the HFHFr group had developed NASH [nonalcoholic fatty liver disease (NAFLD) activity score (NAS): less than 5]. The levels of low-and high-density lipoprotein (LDL and HDL) cholesterol, as well as the levels of ALT and AST, were increased from the end of week 4 to the end of week 8 for the HFHFr and HF groups. At the end of week 16, the two groups differed in the extent of increase in total cholesterol and LDL and HDL cholesterol, with only the HFHFr group showing statistically significant changes. Specifically, at the end of week 16, the HFHFr group showed ALT levels of 108.5 +/- 93.34 U/L (F=5.099, P =0.005 vs. HF group: 44.30 +/- 35.71 U/L, HFr group: 46.70 +/- 17.95 U/L, SC group: 24.70 +/- 6.57 U/L), AST levels of 316.30 +/- 208.98 U/L (F=6.654, P=0.001 vs. HF: 132.12 +/- 75.43 U/L, HFr: 143.30 +/- 38.53 U/L, SC: 122.60 +/- 12.76 U/L), total cholesterol levels of 5.18 +/- 0.58 mmol/L (F=72: 470, P =0.000 vs. HF: 3.94 +/- 0.75 mmol/L, HFr: 2.30 +/- 0.50 mmol/L, SC: 2.02 +/- 0.24 mmol/L), HDL cholesterol levels of 3.05 +/- 0.49 mmol/L (F=25.413, P =0.000 vs. HF: 2.65 +/- 0.54 mmol/L HFr: 1.77 +/- 0.47 mmol/L, SC: 1.58 +/- 0.16 mmol/L), LDL cholesterol levels of 1.11 +/- 0.23 mmol/L (F =83.297, P =0.000 vs. HF: 0.72 +/- 0.17 mmol/L, HFr: 0.27 +/- 0.04 mmol/L, SC: 0.20 +/- 0.05 mmol/ L). CONCLUSION: The present study suggests that a mouse model of NASH can be successfully induced by a 16-week modified HFHFr diet.

αB-Crystallin R120G variant causes cardiac arrhythmias and alterations in the expression of Ca(2+) -handling proteins and endoplasmic reticulum stress in mice.

Mutations of αB-crystallin (CryαB), a small heat shock protein abundantly expressed in cardiac and skeletal muscles, are known to cause desmin-related myopathies. The CryαB R120G allele has been linked to a familial desminopathy and, in transgenic mice, causes a sudden death at about 28 weeks of age. To investigate the mechanisms of the sudden cardiac arrest of CryαB R120G transgenic mice, we prepared protein samples from left ventricular tissues of two different age groups (10 and 28 weeks) and examined Ca(2+) -handling proteins. Expression of sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) 2, phospholamban, ryanodine receptor 2 and calsequestrin 2 was significantly decreased in 28- versus 10-week-old CryαB R120G transgenic mice. In addition, low heart rate variability, including heart rate, total power and low frequency, was observed and continuous electrocardiogram monitoring revealed cardiac arrhythmias, such as ventricular tachycardia, atrioventricular block and atrial flutter, in 28-week-old CryαB R120G transgenic mice. In contrast, expression of endoplasmic reticulum (ER) degradation enhancing α-mannosidase-like protein, inositol requirement 1 and X-box binding protein 1 were increased significantly in 28- versus 10-week-old CryαBR120G transgenic mice, suggesting that the CryαBR120G transgenic mice exhibit increased ER stress compared with wild-type mice. Together, the data suggest that the CryαB R120G dominant variant induces ER stress and impairs Ca(2+) regulation, leading to ageing-related cardiac dysfunction, arrhythmias and decreased autonomic tone with shortened lifespan.

Metabolomic profiling analysis reveals chamber-dependent metabolite patterns in the mouse heart.

Energy of the cardiac muscle largely depends on fatty acid oxidation. It is known that the atrium and ventricle have chamber-specific functions, structures, gene expressions, and pathologies. The left ventricle works as a high-pressure chamber to pump blood toward the body, and its muscle wall is thicker than those of the other chambers, suggesting that energy utilization in each of the chambers should be different. However, a chamber-specific pattern of metabolism remains incompletely understood. Recently, innovative techniques have enabled the comprehensive analysis of metabolites. Therefore, we aimed to clarify differences in metabolic patterns among the chambers. Male C57BL6 mice at 6 wk old were subject to a comprehensive measurement of metabolites in the atria and ventricles by capillary electrophoresis and mass spectrometry. We found that overall metabolic profiles, including nucleotides and amino acids, were similar between the right and left ventricles. On the other hand, the atria exhibited a distinct metabolic pattern from those of the ventricles. Importantly, the high-energy phosphate pool (the total concentration of ATP, ADP, and AMP) was higher in both ventricles. In addition, the levels of lactate, acetyl CoA, and tricarboxylic acid cycle contents were higher in the ventricles. Accordingly, the activities and/or expression levels of key enzymes were higher in the ventricles to produce more energy. The present study provides a basis for understanding the chamber-specific metabolism underlining pathophysiology in the heart.

[The effect of RNA interfering TLR4 signal pathway on phagocytosis of Kupffer cells].

OBJECTIVE: To investigate the effect of RNA interfering TLR4 signal pathway on phagocytosis of Kupffer cells. METHODS: RAW2647 mice mononuclear macrophage leukemia cells were observed. The tested group was interfered by Tlr4-mus-1567 RNA which had the best result confirmed by QPCR, cells interfered by Negative Control RNA as NC group, and normal cell as control. We perform the phagocytosis test on each group. RESULTS: The tested group has lower phagocytes percentage than control (17.67% +/- 3.51% vs 32.00% +/- 3.00%, P < 0.01), and lower phagocytic index (46.33% +/- 7.51% vs 82.00% +/- 6.08%, P < 0.01). CONCLUSIONS: Decreased phagocytic activity was observed on Kupffer cells by RNA interference.