EGFR is a member of the ErbB family of receptor tyrosine kinase inhibitor Bicalutamide kinases (77), which regulate proliferation (29, 64), survival (30, 45), and migration of epithelial cells (8, 48, 49, 75). EGFR is also a target of cross talk by other signaling cascades, such as G protein-coupled receptors (9) and receptors for bacterial LPS (36). Furthermore, signaling through TNF/TNFRs stimulates EGFR phosphorylation (33, 63), resulting in cellular proliferation (3), migration (72), and survival (76). TNF and EGF stimulate the expression of cyclooxygenase (COX)-2, the inducible PG synthase (12, 70). Through generation of PGs, COX-2 regulates diverse biological responses, including cell survival (28, 68, 71), proliferation (58), and migration (10), that promote homeostasis of the colon epithelial monolayer.

COX-2 is thought to be important in IBD, because COX-2 protein expression and PG levels are elevated in the GI tract of IBD patients (32, 59, 62). However, whether COX-2 is pathogenic or cytoprotective in IBD is unclear. Chronic elevation of COX-2 protein expression is a risk factor for colorectal adenocarcinomas (37), and chronic nonsteroidal anti-inflammatory drug use is associated with a decreased risk for the development of colorectal cancer (22, 23, 69). Detailed knowledge of COX-2 regulation by TNFRs and EGFR is critical to the development of therapeutic agents for the treatment of a number of GI diseases. These studies were designed to test the hypothesis that TNF-induced COX-2 expression in GI epithelial cells depends on EGFR transactivation and promotes cell survival.

We also tested which TNFR is required for induction of COX-2, since there are conflicting reports about the relative importance of TNFR1 and TNFR2 in this response (39, 50, 52). We report that COX-2 protects colon epithelial cells from TNF-induced cytotoxicity and that TNF-driven Entinostat COX-2 expression in colon and gastric epithelial cells is via a TNFR1-, EGFR-, Src-, and p38 MAPK-dependent mechanism. MATERIALS AND METHODS Cell lines. The conditionally immortalized young adult mouse colon (YAMC) cell line; TNFR1?/?, TNFR2?/?, and EGFR?/? mouse colon epithelial (MCE) cell lines; COX-1?/? and COX-2?/? MCE cell lines; and TNFR1?/?, TNFR2?/?, COX-1?/?, and COX-2?/? immortalized mouse stomach epithelial (ImSt) cells were isolated from wild-type (WT) or knockout mice crossed with the Immortomouse by Robert Whitehead at the Vanderbilt University Digestive Disease Research Center Novel Cell Line Development Core (74). The cell lines were maintained as previously reported (29). Most of the lines were derived on a C57BL/6 background, but in several cases the mice were of mixed (e.g., EGFR?/? from SV129/C57BL/6) or similar, but not identical (e.g., YAMC from C57BL/10), mice.

Table 1 Patient (n=44) and tumour (n=45) characteristics For the detection of Fas and FasL by western blotting, six frozen primary GIST samples were pulverised and dissolved in ice-cold PBS. After centrifugation at 18000g for 1min to remove debris, the supernatant was collected. Western blot analysis was performed as described http://www.selleckchem.com/products/Enzastaurin.html above. All tumour samples used in this study were handled according to the guidelines of the Dutch Federation of Biomedical Scientific Societies (FMWV) as described in ��Code Proper Secondary Use of Human Tissue’. Tissue microarray construction Representative regions of the paraffin-embedded primary tumours were selected using H&E-stained slides and arrayed into a tissue microarray (TMA), as described previously (Westra et al, 2005). Briefly, three 0.

6mm tissue cores were taken from (distinct) representative areas of each tumour specimen using a manual tissue arrayer (Beecher Instruments, Sun Prairie, WI, USA) and then transferred to a standard-size recipient paraffin block. The array contained 161 tissue cores including 45 tumour samples in triplicate and 13 normal tissues in duplicate, the latter serving as an internal control for immunohistochemistry. Immunohistochemistry Sections of 4��m were taken from each array block and deparaffinised in xylene. Immunohistochemistry was performed as previously described (Arts et al, 2005). Antigen retrieval was carried out by autoclaving sections in blocking solution (2% blocking reagent (Roche Diagnostics, Mannheim, Germany) and 0.2% SDS in maleic acid buffer (pH 6.0)) at 115��C for three times 5min.

Primary antibodies were mouse anti-Fas (clone CH-11, 1:100; Upstate Biotechnology, Lake Placid, NY, USA) and mouse anti-FasL (clone 33, 1:160; BD Transduction Laboratories). As a negative control, a serial section was processed without the addition of primary antibody. Normal tissue samples within the TMA block derived from liver and kidney served as positive controls for Fas and FasL staining (Leithauser et al, 1993; Lee et al, 1999). Staining analysis Immunohistochemistry results were scored independently by two observers (BR and AJHS) without knowledge of the clinicopathological data. As in each individual core all tumour cells showed the same staining, cores were scored in a semiquantitative manner for staining intensity: no staining (0), weakly positive staining (1), positive staining (2), strong positive staining (3).

Discrepant scoring results were discussed under a multiheaded microscope to achieve consensus. If cores from one tumour differed in staining intensity, the median score of the three related cores determined the score of the tumour. Furthermore, the staining pattern was determined from each core. Statistical Entinostat analysis Data analysis was performed using SPSS 12.0 software package for windows (SPSS Inc., Chicago, IL, USA).

In addition, differences at the phylogenetic order level in both dominant and minor bacterial orders were determined Y-27632 msds in the cecal contents. Previous data in humans and rodents have shown that >90% of the microbiota in a normal distal gut is represented by the Bacteroidetes and Firmicutes phyla (21). Among the Bacteroidetes, the Bacteroides class and Bacteroidales order dominate, and, among the Firmicutes, the Clostridia class and Clostridiales order dominate; moreover, members of these phyla have been shown to be influenced by high-fat feeding or obesity (3, 28, 38�C39). An increase in the ��-proteobacteria class, in which belong the order Enterobacteriales and the family Enterobacteriaceae, has also been reported on a HF diet (21).

Host inflammation has also been shown to promote the growth of aerotolerant bacteria such as Enterobacteriaceae (30). Therefore Bacteroidales, Clostridiales, and Enterobacteriales were chosen for the current study. The data showed that consumption of a HF diet induces changes in gut microbiota, but it is the development of inflammation in response to these changes that is associated with the appearance of hyperphagia and an obese phenotype. MATERIALS AND METHODS Animals. Male Sprague-Dawley rats (initial body wt = 262 �� 2 g) were single-housed in a temperature-controlled room with a 12:12-h light-dark cycle and fed either a low-fat diet (LF; Research Diets 12450B) or a HF diet (Research Diets 12451) for 8 or 12 wk. The diets provided 3.85 kcal/g of energy for the LF 70% carbohydrate, 20% protein, 10% fat [saturated fatty acids (SAT), 25.

1%; monounsaturated fatty acids (MUFA), 34.7%; polyunsaturated fatty acids (PUFA), 40.2%] and 4.73 kcal/g of energy for the HF [35% carbohydrate, 20% protein, 45% fat (SAT, 36.3%; MUFA, 45.3%; PUFA, 18.5%)]. Body weight and food intake were recorded daily. Animals were killed after 8 wk (n = 17; LF n = 6, HF = 11) or 12 wk (n Batimastat = 13; LF n = 5, HF = 8). An additional group of rats (n = 12; LF n = 4, HF = 8) were fed diets for 12 wk, and body weight was recorded weekly. All experiments were performed in accordance with protocols reviewed and approved by the Institutional Animal Care and Use Committee, University of California Davis. Measurement of gut permeability in vivo. After 10 wk on the diet, rats were fasted for 6 h and gavaged with 4,000 kDa FITC-labeled dextran diluted in saline (Sigma-Aldrich, St. Louis, MO) (500 mg/kg, 125 mg/ml). After 1 h, blood (500 ��l) was collected from the tail vein and centrifuged (10,000 rpm for 3 min at 4��C), and FITC-dextran concentration in plasma was determined by spectrophotometry (excitation wavelength 485 nm; emission wavelength 535 nm; SpectraMax M2; Molecular Devices, Sunnyvale, CA). Tissue collection.

A bioinformatic analysis of the GGDEF domain sequence and structure published in 2001 by Pei and Grishin (109) was also useful selleck screening library in connecting this domain to the cyclase activity. These authors discovered that the GGDEF domain is distantly related to the catalytic domain of adenylate/guanylate nucleotide cyclases (110, 111). While primary sequence similarity between these domains is low, the predicted secondary and tertiary structures of the GGDEF domain are remarkably similar to those of the type III adenylate cyclase. Pei and Grishin proposed that the GGDEF domain is a DGC and predicted the loop involving the most conserved signature motif, GG(D/E)EF, to be part of the substrate (GTP) binding site. The first biochemical evidence solidifying this connection came from a study by Paul et al.

(37), who showed that the phosphorylated form of PleD converts GTP into c-di-GMP in vitro. This was also observed by Hickman et al. (93) and Ryjenkov et al. (42). The latter study analyzed in vitro activities of six different GGDEF domain enzymes originating from representatives of diverse branches of the bacterial phylogenetic tree, including Alpha- and Gammaproteobacteria as well as Thermotogae, Deinococcus-Thermus, Cyanobacteria, and Spirochaetes. All of these GGDEF domain proteins possessed DGC activity and were incapable of utilizing nucleotide substrates other than GTP. Therefore, the ubiquity and evolutionary conservation of c-di-GMP envisioned earlier (25) were established experimentally (Fig. 2). Fig 2 Basic biochemistry of c-di-GMP synthesis, degradation, and c-di-GMP receptors.

The diagrams show the protein domains involved in c-di-GMP metabolism and signaling. Enzymatically active GGDEF, EAL, and HD-GYP domains are shown on a white background. Enzymatically … How do GGDEF domain proteins catalyze c-di-GMP formation? The early insights into this question were obtained by Benziman and colleagues (1), who revealed that c-di-GMP formation from 2 molecules of GTP is a two-step reaction proceeding via 5��-pppGpG as a reaction intermediate (Fig. 2). Two molecules of pyrophosphate are reaction by-products. A further mechanistic understanding of c-di-GMP synthesis came from the biochemical and structural characterization of DGCs. The apparent similarity of DGCs to type III nucleotide cyclases, as well as the dinucleotide nature of c-di-GMP, implied that GGDEF domains function as homodimers, where two monomers come together to form an active site at the dimer interface (112). Each GGDEF monomer contributes a GTP substrate to the formation of an intermolecular Carfilzomib phosphoester bond to another molecule of GTP. It was observed that purified GGDEF domains by themselves form homodimers and, at high concentrations, show low-level DGC activity.

4��0.9 up to 39.1��3.7% in BDL mice (Figure 5, P<0.05 vs sham, Enzalutamide solubility n=7�C8). The number of non-perfused sinusoids after BDL decreased to 15.7��3.2% in platelet-depleted animals (Figure 5, P<0.05 vs Control ab+BDL, n=7�C8). Moreover, administration of the ab directed against P-selectin reduced perfusion failure to 16.5��2.8% in BDL mice (Figure 5, P<0.05 vs Control ab+BDL, n=7�C8). We also noted numerous and widespread aggregates (that is more than three platelets) of platelets in the hepatic microvasculature after ligation of the common bile duct. The number of these platelet aggregates increased by 16- and 30-fold in sinusoids and postsinusoidal venules, respectively, in BDL mice (Figure 6, P<0.05 vs sham, n=7�C8).

Administration of the anti-GP-1b�� and the anti-P-selectin ab abolished BDL-induced formation of platelet aggregates in the hepatic microcirculation (Figure 6, P<0.05 vs Control ab+BDL, n=7�C8). Figure 5 Sinusoidal perfusion failure 12h after ligation of the common bile duct. Mice were pretreated i.v. with an iso-type control antibody (Control ab), an antibody against GP1b�� (anti-GP1b�� ab) or against P-selectin (anti-P-selectin ... Figure 6 Platelet aggregates in (a) sinusoids and (b) postsinusoidal venules 12h after ligation of the common bile duct. Mice were pretreated i.v. with an iso-type control antibody (Control ab), an antibody against GP1b�� (anti-GP1b�� ab) ... CXC chemokines Leukocyte extravasation into the liver parenchyma has been reported to be directed by secreted CXC chemokines (Li et al., 2004).

We observed that the hepatic levels of CXC chemokines in sham animals were low but detectable (Figure 7, n=6�C8). In contrast, ligation of the common bile duct markedly increased hepatic levels of MIP-2 and KC (Figure 7, P<0.05 vs sham, n=6�C8). Interestingly, pretreatment with the anti-GP-1b�� ab reduced BDL-provoked expression of MIP-2 and KC. That is, depletion of platelets attenuated formation of CXC chemokines by more than 63% in cholestatic mice (Figure 7). Similarly, administration of the anti-P-selectin ab significantly reduced BDL-induced expression of MIP-2 by 73% and of KC by 66% (Figure 7, P<0.05 vs Control ab+BDL, n=6�C8). Figure 7 Hepatic levels of (a) macrophage inflammatory protein-2 (MIP-2) and (b) cytokine-induced neutrophil chemoattractant (KC) 12h after ligation of the common bile duct. Mice were pretreated i.

v. with an iso-type control antibody (Control ab), an … Discussion and conclusions Surgical and endoscopic decompression is the principal treatment of biliary obstruction but may not be sufficient to prevent development of hepatic injury and septic complications. Thus, mechanistic studies are needed to delineate the pathophysiology of cholestasis-induced liver damage. This study Brefeldin_A demonstrates for the first time an important role of platelets in supporting BDL-mediated leukocyte recruitment in the liver.

S. Department of Health and Human Services, 2006). SHS-related disease and financial burden are fundamental public health concerns reflected in the Framework Convention on Tobacco Control, advocated by 168 countries under the World Health Organization (WHO) sponsorship (WHO, nothing 2003). SHS exposure elimination is considered an attainable primary prevention goal to reduce morbidity and mortality (WHO, 2008). Efforts to eliminate the health risks associated to SHS can be classified into two categories. First, some countries have allowed mechanical systems, such as area separation, ventilation, and air extraction, in an attempt to reduce SHS exposure while still allowing smoking (WHO, 2009). These types of mechanical systems are advocated by tobacco companies and the hospitality sector as effective means to reduce SHS (Drope, Bialous, & Glantz, 2004).

Some experimental research partially supports this claim. For instance, working under ideal circumstances, the most sophisticated smoking rooms, which combine several mechanical systems, are capable of eliminating 90% of SHS (Wagner et al., 2004). The remaining 10%, however, is still transferred to nonsmoking areas. Thus, while mechanical systems may significantly reduce SHS, they can not completely eliminate it. Second, legislative action against tobacco smoke has increasingly gained public support and has led to substantial changes in policies around the world (WHO, 2008). Currently, 17 countries have followed 100% smoke-free environment policies, advocating complete smoking bans in all public places (WHO, 2009).

The WHO position is grounded on evidence showing that no safe levels of exposure to SHS exist (U.S. Department of Health and Human Services, 2006); therefore, all residuals and leakage resulting from the insufficient capability of mechanical systems represent a significant health risk (WHO, 2007). Complete smoking bans have received support from the American Society of Heating, Refrigerating, and Air Conditioning Engineers, who state that no engineering approach is capable of eliminating the health risks associated with SHS once the smoke has been released to the environment (Samet et al., 2005). While a vast body of literature has been dedicated to discussing mechanical systems versus smoking bans (Akbar-Khanzadeh, 2003; Cenko, Pisaniello, & Esterman, 2004; Dearlove, Bialous, & Glantz, 2002; Drope et al.

, 2004; Samet et al., 2005; WHO, 2008), no systematic attempt has been conducted to quantify the effectiveness of each approach under nonexperimental conditions. In February 2008, a total smoking ban in all public places, including restaurants and bars, was GSK-3 enforced in Mexico City (Gaceta Oficial del Distrito Federal, 2008). The rest of the country, however, still allowed indoor smoking.

Indeed, recent studies have demonstrated that anti-inflammatory agents such as lisofylline are beneficial in attenuating or preventing disease [24]�C[26]. Both clinical and basic research studies demonstrate that immune cells and inflammatory mediators, http://www.selleckchem.com/products/z-vad-fmk.html including cytokines, play vital roles in the pathogenesis of diabetes and its complications. However, it is not clear whether pancreatic �� cell injury induced by chronic CsA treatment is associated with immune cell infiltration and cytokine production. Our results clearly showed that chronic CsA treatment significantly increased not only the number of macrophages infiltrating islets (by about 1.5-fold) but also the level of iNOS and proinflammatory cytokines in pancreatic �� cells.

CsA treatment also induced significantly increased levels of nitrite, an indicator of NO production, in the culture medium from INS-1 cells. When KRG treatment is combined with CsA treatment in vivo, we predict that KRG will protect pancreatic �� cells against the CsA-induced inflammatory microenvironment described above. In fact, several studies have demonstrated that KRG inhibits the production of inflammatory cytokines and activation of NF��B, suggesting that it has an anti-inflammatory effect [27], [28]. The results of our in vivo study show that oral administration of KRG reduced CsA-induced macrophage infiltration and the levels of i
Hepatitis C virus (HCV) infection represents one of the leading causes of chronic hepatitis worldwide, resulting in progression into fibrosis, cirrhosis and hepatocellular carcinoma in a significant number of HCV-infected patients [1].

The HCV prevalence is estimated to be 3% worldwide [2] and 0.2�C0.5% in the Czech Republic with predominance of genotype 1 (79.3%) and 3 (19.7%) [3], [4]. Although HCV is mainly hepatotropic, there is also evidence that it can replicate in the peripheral blood mononuclear cells (PBMC) of patients with chronic HCV infection [5]. Oxidative damage has been hypothesized to play a role in HCV-induced liver disease, with reactive oxygen and nitrogen species (RONS) generated from HCV-infected hepatocytes, and infiltrating the immune cells [6], [7]. HCV might not only increase RONS production, but also downregulate expression of certain antioxidant genes, including heme oxygenase (HMOX) [8]. HMOX catalyzes the degradation of the pro-oxidative heme to biliverdin, carbon monoxide (CO), and iron (Figure 1).

Biliverdin is then subsequently reduced to bilirubin by biliverdin reductase Entinostat (BLVR). Biliverdin, bilirubin, and CO exert numerous biological functions, including anti-oxidative and anti-inflammatory effects, as well as the modulation of cell proliferation and apoptosis [9], [10], [11]. Two HMOX isoforms have evolved, which include HMOX1 (OMIM*141250), an inducible isoenzyme, and HMOX2 (OMIM*141251), a constitutive isoform.

Forty-eight hours after viral transduction, hygromycin B (Invitrogen) was included in the medium at a concentration of 25 ��g/ml for 2 weeks. Following drug selection, individual colonies were picked and expanded into cell lines. To generate drug-resistant cancer cells, Hepa1�C6 cells were http://www.selleckchem.com/products/chir-99021-ct99021-hcl.html transfected with a neomycin resistance gene and a green fluorescent protein gene with the Effectene Transfection Reagent kit (Qiagen). Forty-eight hours after transduction, neomycin (Invitrogen) was included in the culture medium at a concentration of 100 ��g/ml, and individual colonies were picked at day 14 and expanded into cell lines. Cell Fusion For polyethylene glycol fusions, cells of each type (generally 5 �� 106) were combined in serum-free Glasgow minimum essential medium in a conical tube and pelleted.

After the supernatant was aspirated, the pellet was broken by gentle tapping, and 1 ml of 50% w/v polyethylene glycol 1500 (Roche Diagnostics, Basel, Switzerland) prewarmed to 37 ��C was gently added. Cells were incubated in the 50% polyethylene glycol solution for 1 min with occasional stirring. Then, 1 ml of medium was added over a period of 1 min. Subsequently, an additional 3 ml of medium was added. Cells were centrifuged, and the supernatant was discarded. The pellet was resuspended in complete ES cell medium and plated. Selection was applied after 48 h using hygromycin (200 mg/ml) and neomycin (100 mg/ml). Fourteen days following drug selection, single colonies were picked and expanded under standard conditions. Karyotype Analysis A 25-cm flask at 60% cell confluence was treated with 0.

04�C0.1 ��g/ml colchicine for 3 h. Cells were recovered by trypsinization and treated with a hypotonic (0.56% w/v) KCl solution for 15 min. The cells were centrifuged at 500 rpm, fixed by washing three times in fresh fixative (3:1 methanol:acetic acid), and dropped onto cold, clean glass slides. The slides were air-dried, stained with 4��,6-diamidino-2-phenylindole, and observed under a microscope. Fluorescence-activated Cell Sorting For analysis of DNA content, cells in a 10-cm dish were trypsinized, washed in phosphate-buffered saline (PBS), and fixed with 70% ethanol at 4 ��C for 30 min. RNase A was added to 500 ��l of PBS at a final concentration of 20 ��g/ml. Cells were incubated in this solution at 37 ��C for 30 min and then centrifuged at 1500 rpm for 5 min. The supernatant was discarded, and the cells were incubated Brefeldin_A with propidium iodide in 500 ��l of PBS at a final concentration of 50 ��g/ml in the dark at room temperature for 30 min and then centrifuged at 1500 rpm for 5 min. The supernatant was discarded again, and the cells were resuspended in 0.5 ml of PBS. The stained cells were analyzed with the FACSCalibur system (BD Biosciences).

Finally, as data were collected at three sites, effects for site were also tested. RESULTS Participant Characteristics selleckchem Dovitinib Detailed participant characteristics can be found in Tables 1 and and2.2. Retention rates by treatment condition are shown in Table 3. The study sample was predominantly male, ethnically/racially diverse, and of low socioeconomic status. Less than a fifth of the sample was employed, and a large proportion was homeless or living in transitional housing. Rates of lifetime psychiatric disorders and illicit drug use in the past month were high. Significant differences between treatment groups were found on three variables. Smokers in the SH condition were older (p < .01) and more likely to have a history of a major depressive episode (p < .05) than participants in the other two conditions.

Smokers in the CBI condition were more likely to have met criteria for bipolar disorder than the other two conditions (p < .05). Table 3. Percent Abstinent (a) and Mean Number of Cigarettes Smoked (b) by Treatment Condition and Assessment Week The number of cigarettes smoked per day and the Fagerstr?m dependence score indicate moderate levels of nicotine dependence. Less than half of the sample (44%) endorsed a smoking treatment goal of total cigarette abstinence. These baseline characteristics are consistent with clinic census data indicating that the sample is representative of the clinic populations. Smoking Outcome Percentage smoking abstinent ranged from 15% to 29% with no statistically significant difference among the treatment conditions (Figure 2 and Table 3).

Estimates from the mixed-effects regression model are summarized in Table 4. Those employed, those who reported a greater desire to quit, or those with lower mood disturbance scores were more likely to achieve abstinence. Table 4. Estimates and Tests of Model Parameters Figure 2. Analyses of point prevalence abstinence rates by treatment condition and time indicate no significant overall differences between treatments across time. No differences in sustained abstinence were found nor were there effects based on recruitment site. However, the number of cigarettes participants reported smoking in the 24hr prior to each assessment significantly declined over time (p < .001) with means at each assessment of 17.8, 8.7, 10.5, 11.1, and 11.5.

The treatment conditions did not differ in this decline (see Table 3), and a similar effect was found when participants Batimastat were asked about the number of cigarettes in the prior week. NRT Use Self-report of NRT use was not collected. NRT distribution was recorded as a surrogate of NRT compliance. There were no significant differences in NRT distribution as a function of treatment condition. Mean number of patches distributed was 51.5, 44.7, and 47.0 for participants in the SH, CBI, and IC conditions, respectively (p = .172). Mean pieces of gum distributed was 530.9, 467.5, and 471.

These bioactive mediators may have harmful effects on hepatocytes. To examine the hypothesis that activated KCs mediate hepatic injury, we established a noncontact coculture model using the supernatants of SiO2 NP-stimulated KCs to culture BRL cells. In addition to the morphological changes (Figure 4), we also observed that the viability of BRL cells was reduced, and leakage of LDH no and AST increased (Figure 3). LDH and AST are relatively stable enzymes in BRL cells, thus their leakage from the intracellular compartment of hepatocytes into the extracellular space indicates that plasma membrane disruption and hepatocyte damage have occurred.32,33 In this study, the elevated levels of these enzymes in the supernatants of BRL cells may be correlated with the increased release of ROS, TNF-��, and NO by activated KCs, as previously mentioned.

Studies have demonstrated that ROS are capable of causing oxidative damage to major cellular structures, in particular the mitochondria and the plasma membrane.34,35 NO has been reported to downregulate cytochrome P450 and to suppress liver protein and DNA synthesis, and these activities may contribute to hepatotoxicity.36 Additionally, TNF-��, a potent inflammatory cytokine produced by activated KCs, can induce multiple mechanisms to initiate apoptosis in hepatocytes that leads to hepatic injury.37 These data suggest that KCs activated by SiO2 NPs mediate hepatotoxicity and that the preliminary mechanism might occur through the release of ROS, TNF-��, and NO. An in vivo analysis was carried out to determine whether SiO2 NPs activate KCs and induce liver injury.

The results showed that the number of sinusoidal KCs increased after administration of SiO2 NPs (Figure 5E and F), which indicated that SiO2 NPs activated the phagocytic activity of sinusoidal cells by increasing the number of KCs to help remove accumulating nanoparticles.38 The observed hyperplasia and activation of KCs could also lead to the increased formation of bioactive mediators contributing to hepatic injury, such as ROS, TNF-��, and NO, which we demonstrated in the in vitro study. Additionally, we observed infiltration of inflammatory cells into the liver and increases in the serum levels of WBC, LYM, MONO, NEU, and TNF-��, which suggests that SiO2 NPs may induce inflammation.

Aderem39 reported that inflammation may result from the internalization of nanoparticles into macrophages and the subsequent activation of these macrophages. Because KCs can phagocytose SiO2 NPs and become activated, we deduced that KCs played a critical role in the inflammation that we observed. There is a link between inflammation and oxidative AV-951 stress where recruited inflammatory cells can generate oxidative stress by activating oxidative stress responsive transcription factors.40 In this study, we found that SiO2 NPs caused oxidative stress in the liver, with a decrease in GSH activity and an elevation in MDA levels.