Glycated human serum albumin enhances macrophage inflammatory protein-1β mRNA expression through protein kinase C-δ and NADPH oxidase in macrophage-like differentiated U937 cells

Single Donor Infusion of S-Nitroso-Human-Serum-Albumin Attenuates Cardiac Isograft Fibrosis and Preserves Myocardial Micro-RNA-126-3p in a Murine Heterotopic Heart Transplant Model

Objectives: Cold ischemia and subsequent reperfusion injury are non-immunologic cornerstones in the development of graft injury after heart transplantation. The nitric oxide donor S-nitroso-human-serum-albumin (S-NO-HSA) is known to attenuate myocardial ischemia-reperfusion (I/R)-injury. We assessed whether donor preservation with S-NO-HSA affects isograft injury and myocardial expression of GATA2 as well as miR-126-3p, which are considered protective against vascular and endothelial injury.

Methods: Donor C57BL/6 mice received intravenous (0.1 μmol/kg/h) S-NO-HSA (n = 12), or 0.9% saline (control, n = 11) for 20 min. Donor hearts were stored in cold histidine-tryptophan-α-ketoglutarate-N solution for 12 h and underwent heterotopic, isogenic transplantation, except 5 hearts of each group, which were analysed immediately after preservation. Fibrosis was quantified and expression of GATA2 and miR-126-3p assessed by RT-qPCR after 60 days or immediately after preservation.

Results: Fibrosis was significantly reduced in the S-NO-HSA group (6.47% ± 1.76 vs. 11.52% ± 2.16; p = 0.0023; 12 h-S-NO-HSA-hHTX vs. 12 h-control-hHTX). Expression of miR-126-3p was downregulated in all hearts after ischemia compared to native myocardium, but the effect was significantly attenuated when donors received S-NO-HSA (1 ± 0.27 vs. 0.33 ± 0.31; p = 0.0187; 12 h-S-NO-HSA-hHTX vs. 12 h-control-hHTX; normalized expression to U6 snRNA).

Conclusion: Donor pre-treatment with S-NO-HSA lead to reduced fibrosis and preservation of myocardial miR-126-3p and GATA2 levels in murine cardiac isografts 60 days after transplantation.

Mechanisms of disease-modifying effect of saracatinib (AZD0530), a Src/Fyn tyrosine kinase inhibitor, in the rat kainate model of temporal lobe epilepsy

We have recently demonstrated the role of the Fyn-PKCδ signaling pathway in status epilepticus (SE)-induced neuroinflammation and epileptogenesis in experimental models of temporal lobe epilepsy (TLE). In this study, we show a significant disease-modifying effect and the mechanisms of a Fyn/Src tyrosine kinase inhibitor, saracatinib (SAR, also known as AZD0530), in the rat kainate (KA) model of TLE. SAR treatment for a week, starting the first dose (25 mg/kg, oral) 4 h after the onset of SE, significantly reduced spontaneously recurring seizures and epileptiform spikes during the four months of continuous video-EEG monitoring. Immunohistochemistry of brain sections and Western blot analyses of hippocampal lysates at 8-day (8d) and 4-month post-SE revealed a significant reduction of SE-induced astrogliosis, microgliosis, neurodegeneration, phosphorylated Fyn/Src-419 and PKCδ-tyr311, in SAR-treated group when compared with the vehicle control. We also found the suppression of nitroxidative stress markers such as iNOS, 3-NT, 4-HNE, and gp91phox in the hippocampus, and nitrite and ROS levels in the serum of the SAR-treated group at 8d post-SE. The qRT-PCR (hippocampus) and ELISA (serum) revealed a significant reduction of key proinflammatory cytokines TNFα and IL-1β mRNA in the hippocampus and their protein levels in serum, in addition to IL-6 and IL-12, in the SAR-treated group at 8d in contrast to the vehicle-treated group. These findings suggest that SAR targets some of the key biomarkers of epileptogenesis and modulates neuroinflammatory and nitroxidative pathways that mediate the development of epilepsy. Therefore, SAR can be developed as a potential disease-modifying agent to prevent the development and progression of TLE.

Take Immune Cells Back on Track: Glycopolymer-Engineered Tumor Cells for Triggering Immune Response

The "self-homing" of cancer cells to primary or metastatic tumor sites indicates that they could serve as vehicles for self-targeted cancer therapy; this suggests a promising method for treating end-stage cancer. Inspired by this, we propose that engineering cancer cells to carry efficient "coup" molecules for in situ activation of immune cells in or near tumor sites to attack tumors is a promising strategy for cancer therapy. Therefore, herein we explored the potential of engineered tumor cells to enhance their anticancer activity by stimulating immune cells. We armed tumor cell surfaces with specific glycopolymer-ligands that bind to lectins on macrophages or dendritic cells by combining HaloTag protein (HTP) fusion technique with reversible addition-fragmentation chain transfer (RAFT) polymerization. We demonstrated that two synthetic well-defined glycopolymers containing, respectively, N-acetylglucosamine and N-acetylmannosamine units, were introduced and stably presented on the cell surfaces via the stable covalent binding of chloroalkane-terminated polymers with membrane-bound HTP. Furthermore, it was shown that the glycopolymer-engineered HeLa cells with HTP anchors increased expression of the typical marker for M1-type macrophages (CD86) and upregulated secretion of pro-inflammatory cytokines (IL-12p70, TNF-α, and iNOS), thereby accelerating HeLa cell lysis. The maturation of dendritic cells was also promoted. This study demonstrates the strong potential of glycopolymer-engineered tumor cells in cancer immunotherapy.

Comprehensive evaluation of antioxidant effects of Japanese Kampo medicines led to identification of Tsudosan formulation as a potent antioxidant agent

Oxidative stress due to the overproduction of reactive oxygen species plays an important role in the pathogenesis of various diseases. In the present study, we comprehensively evaluated the antioxidant activities of 147 oral formulations of Japanese traditional herbal medicines (Kampo medicines), representing the entire panel of oral Kampo medicines listed in the Japanese National Health Insurance Drug List, using in vitro radical scavenging assays, including the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity assay, the superoxide anion scavenging activity assay, and the oxygen radical absorption capacity assay. Three of the formulations tested, namely, Tsudosan, Daisaikoto, and Masiningan, showed the most potent in vitro antioxidant activities and were selected for further investigation of their intracellular and in vivo antioxidant effects. The results of the 2',7'-dichlorodihydrofluorescin diacetate assay demonstrated that all three Kampo medicines significantly inhibited hydrogen peroxide-induced oxidative stress in human hepatocellular liver carcinoma HepG2 cells. In addition, Tsudosan significantly increased the serum biological antioxidant potential values when orally administrated to mice, indicating that it also had in vivo antioxidant activity. The potent antioxidant activity of Tsudosan may be one of the mechanisms closely correlated to its clinical usage against blood stasis.

Wu-Tou Decoction in Rheumatoid Arthritis: Integrating Network Pharmacology and In Vivo Pharmacological Evaluation

Purpose: This study aimed to explore underlying action mechanism of Wu-Tou decoction (WTD) in rheumatoid arthritis (RA) through network pharmacology prediction and experimental verification. Methods: Chemical compounds and human target proteins of WTD as well as RA-related human genes were obtained from TCM Database @ Taiwan, PubChem and GenBank, respectively. Subsequently, molecular networks and canonical pathways presumably involved in the treatment of WTD on RA were generated by ingenuity pathway analysis (IPA) software. Furthermore, experimental validation was carried out with MIP-1β-induced U937 cell model and collagen induced arthritis (CIA) rat model. Results: CCR5 signaling pathway in macrophages was shown to be the top one shared signaling pathway associated with both cell immune response and cytokine signaling. In addition, protein kinase C (PKC) δ and p38 in this pathway were treated as target proteins of WTD in RA. In vitro experiments indicated that WTD inhibited MIP-1β-induced production of TNF-α, MIP-1α, and RANTES as well as phosphorylation of CCR5, PKC δ, and p38 in U937 cells. WTD treatment maintained the inhibitory effects on production of TNF-α and RANTES in MIP-1β-induced U937 cells after CCR5 knockdown. In vivo experiments demonstrated that WTD ameliorated symptoms in CIA rats, decreased the levels of IL-1β, IL-2, IL-6, TNF-α, MIP-1α, MIP-2, RANTES, and IP-10 in serum of CIA rats, as well as mRNA levels of MIP-1α, MIP-2, RANTES, and IP-10 in ankle joints of CIA rats. Furthermore, WTD also lowered the phosphorylation levels of CCR5, PKC δ and p38 in both ankle joints and macrophages in ankle joints from CIA rats. Conclusion: It was demonstrated in this research that WTD played a role in inhibiting inflammatory response in RA which was closely connected with the modulation effect of WTD on CCR5 signaling pathway in macrophages.

Glycolaldehyde and maleyl conjugated human serum albumin as potential macrophage-targeting carriers for molecular imaging purposes

Maleylated bovine serum albumin is a known ligand for targeting macrophages and has potential as a carrier for molecular imaging purposes. We present a novel synthesis of glycolaldehyde-conjugated human serum albumin (GA-HSA) and maleylated human serum albumin (Mal-HSA). Seventeen modifications of fluorescently tagged GA-HSA and Mal-HSA molecules with different degrees of conjugation were prepared. The comparative uptake studies, using 12 of these modifications, were done in vitro on mouse monocytes/macrophages (RAW264.7), and evaluated qualitatively by confocal microscopy and quantitatively by flow cytometry. The GA modifications are taken up by the macrophages approximately 40% better than the maleyl modifications at low concentrations (≤ 3 μM), while at higher concentrations it appears that the maleyl modifications are taken up around 25-44% better than the GA-modified HSA. However, high uptake at low concentrations will be beneficial for in vivo localizing inflammation in areas with low penetration of the probe as in an atherosclerotic plaque. Further, another advantage of GA-HSA is that GA competes less than the maleyl group for the free reactive amine sites that are to be used for conjugation of metal chelating ligands (e.g. tetraazacyclododecanetetraacetic acid and triazacyclononanetriacetic acid). Metal ions such as Gd(3+) and Mn(2+) can be chelated for positive Magnetic Resonance (MR) contrast and positron emitting ions such as (64) Cu(2+) and (68) Ga(3+) for Positron Emission Tomography (PET) imaging. These are important properties, especially, when considering the MR contrast possibilities owing to the low sensitivity of the technique, and would motivate the use of GA-HSA before Mal-HSA.

Targeted iron-oxide nanoparticle for photodynamic therapy and imaging of head and neck cancer

Photodynamic therapy (PDT) is a highly specific anticancer treatment modality for various cancers, particularly for recurrent cancers that no longer respond to conventional anticancer therapies. PDT has been under development for decades, but light-associated toxicity limits its clinical applications. To reduce the toxicity of PDT, we recently developed a targeted nanoparticle (NP) platform that combines a second-generation PDT drug, Pc 4, with a cancer targeting ligand, and iron oxide (IO) NPs. Carboxyl functionalized IO NPs were first conjugated with a fibronectin-mimetic peptide (Fmp), which binds integrin β1. Then the PDT drug Pc 4 was successfully encapsulated into the ligand-conjugated IO NPs to generate Fmp-IO-Pc 4. Our study indicated that both nontargeted IO-Pc 4 and targeted Fmp-IO-Pc 4 NPs accumulated in xenograft tumors with higher concentrations than nonformulated Pc 4. As expected, both IO-Pc 4 and Fmp-IO-Pc 4 reduced the size of HNSCC xenograft tumors more effectively than free Pc 4. Using a 10-fold lower dose of Pc 4 than that reported in the literature, the targeted Fmp-IO-Pc 4 NPs demonstrated significantly greater inhibition of tumor growth than nontargeted IO-Pc 4 NPs. These results suggest that the delivery of a PDT agent Pc 4 by IO NPs can enhance treatment efficacy and reduce PDT drug dose. The targeted IO-Pc 4 NPs have great potential to serve as both a magnetic resonance imaging (MRI) agent and PDT drug in the clinic.

Statin-dependent activation of protein kinase Cδ in acute promyelocytic leukemia cells and induction of leukemic cell differentiation

Statins are HMG-CoA (3-hydroxy-3-methyl-glutaryl-coenzyme A) reductase inhibitors, which block the conversion of HMG-CoA to mevalonate and have potent cholesterol lowering properties. Beyond their importance in the generation of lipid lowering effects, the regulatory effects of statins on the mevalonate pathway have a significant impact on multiple other cellular functions. There is now extensive evidence that statins have anti-inflammatory and anti-neoplastic properties, but the precise mechanisms by which such responses are generated are not well understood. In the present study we demonstrate that statins engage a member of the protein kinase C (PKC) family of proteins, PKCδ, in acute promyelocytic leukemia (APL) cells. Our study shows that atorvastatin and fluvastatin induce proteolytic activation of PKCδ in the APL NB4 cell line, which expresses the t(15;17) translocation. Such engagement of PKCδ results in induction of its kinase domain and downstream regulation of pathways important for statin-dependent leukemia cell differentiation. Our research shows that the function of PKCδ is essential for statin-induced leukemic cell differentiation, as demonstrated by studies involving selective targeting of PKCδ using siRNAs. We also demonstrate that the potent enhancing effects of statins on all-trans retinoic acid (ATRA)-induced gene expression for CCL3 and CCL4 requires the function of PKCδ, suggesting a mechanism by which statins may promote ATRA-induced antileukemic responses. Altogether, our data establish a novel function for PKCδ as a mediator of statin-induced differentiation of APL cells and antileukemic effects.

NAD(P)H oxidase participates in the palmitate-induced superoxide production and insulin secretion by rat pancreatic islets

Nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase complex has been shown to be involved in the process of glucose-stimulated insulin secretion (GSIS). In this study, we examined the effect of palmitic acid on superoxide production and insulin secretion by rat pancreatic islets and the mechanism involved. Rat pancreatic islets were incubated during 1 h with 1 mM palmitate, 1% fatty acid free-albumin, 5.6 or 10 mM glucose and in the presence of inhibitors of NAD(P)H oxidase (DPI--diphenyleneiodonium), PKC (calphostin C) and carnitine palmitoyl transferase-I (CPT-I) (etomoxir). Superoxide content was determined by hydroethidine assays. Palmitate increased superoxide production in the presence of 5.6 and 10 mM glucose. This effect was dependent on activation of PKC and NAD(P)H oxidase. Palmitic acid oxidation was demonstrated to contribute for the fatty acid induction of superoxide production in the presence of 5.6 mM glucose. In fact, palmitate caused p47(PHOX) translocation to plasma membrane, as shown by immunohistochemistry. Exposure to palmitate for 1 h up-regulated the protein content of p47(PHOX) and the mRNA levels of p22(PHOX), gp91(PHOX), p47(PHOX), proinsulin and the G protein-coupled receptor 40 (GPR40). Fatty acid stimulation of insulin secretion in the presence of high glucose concentration was reduced by inhibition of NAD(P)H oxidase activity. In conclusion, NAD(P)H oxidase is an important source of superoxide in pancreatic islets and the activity of NAD(P)H oxidase is involved in the control of insulin secretion by palmitate.

Circulating glycolaldehyde induces oxidative damage in the kidney of rats

Renal failure is a key pathological issue in diabetic patients. Increased levels of advanced glycation end-products (AGEs) have been associated to diabetic complications, including diabetic nephropathy. Models of AGE-treated animals have been applied to evaluate the effect of such molecules on oxidative parameters involved in the pathogenesis and evolution of diabetes disease. However, little is known about the effect of glycating agents other than glucose. Here we investigate the effect of intravenously administrated glycolaldehyde (GA) on oxidative stress parameters of the kidney. Male Wistar rats received a single injection of GA in different doses (10, 50 or 100mg/kg) and were sacrificed after 6, 12 or 24h. Activities of antioxidant enzymes catalase, superoxide dismutase and glyoxalase I were assayed. Damage to proteins and lipids were also assayed. The content of N(epsilon)-(carboxymethyl)lysine (CML) was quantified. Glycolaldehyde induced a decrease in the activity of all enzymes studied. Lipoperoxidation and protein carbonylation raised, accompanied by a decrease in sulfhydryl groups. Despite the oxidative stress generated by GA, no change was found in the content of CML, suggesting that accumulation of AGEs in the kidney might occur at later steps in the development of diabetic nephropathy.

Advanced glycation end products induce production of reactive oxygen species via the activation of NADPH oxidase in murine hepatic stellate cells

BACKGROUND & AIMS

Advanced glycation end products are known to play an important role in the metabolic syndrome and were recently suggested to contribute to liver fibrosis development. However, little is known about the effect of advanced glycation end products on hepatic stellate cells, the major contributors to liver fibrosis development. We therefore studied the effect of advanced glycation end products on reactive oxygen species generation, a main feature for the activation hepatic stellate cells.

METHODS

Three different types of advanced glycation end products were generated by BSA incubation with different substrates. The presence of advanced glycation end product receptors was examined by RTq-PCR, immunofluorescence and western blotting. Reactive oxygen species production was measured using DCFH-DA.

RESULTS

Hepatic stellate cells express five advanced glycation end product receptors: Galectin-3, CD36, SR-AI, SR-BI and RAGE. All receptors, except SR-BI, showed up-regulation during HSC activation. All three advanced glycation end product types induced reactive oxygen species generation. DPI and NSC, a NADPH oxidase and a Rac1 inhibitor respectively, inhibited reactive oxygen species production. Rottlerin, a molecule often used as a PKCdelta inhibitor, also abrogated reactive oxygen species production. SiRNA mediated knockdown of p47(phox), Rac1 and PKCdelta decreased reactive oxygen species production induced by advanced glycation end products, establishing a role for these proteins in reactive oxygen species induction.

CONCLUSIONS

The demonstration of advanced glycation end product-induced reactive oxygen species generation in hepatic stellate cells unveils a potential new route through which advanced glycation end products induce liver fibrosis in the metabolic syndrome.

AGER1 regulates endothelial cell NADPH oxidase-dependent oxidant stress via PKC-delta: implications for vascular disease

Advanced glycated end-product receptor 1 (AGER1) protects against vascular disease promoted by oxidants, such as advanced glycated end products (AGEs), via inhibition of reactive oxygen species (ROS). However, the specific AGEs, sources, and pathways involved remain undefined. The mechanism of cellular NADPH oxidase (NOX)-dependent ROS generation by defined AGEs, N(epsilon)-carboxymethyl-lysine- and methylglyoxal (MG)-modified BSA, was assessed in AGER1 overexpressing (AGER1(+) EC) or knockdown (sh-mRNA-AGER1(+) EC) human aortic endothelial (EC) and ECV304 cells, and aortic segments from old (18 mo) C57BL6-F(2) mice, propagated on low-AGE diet (LAGE), or LAGE supplemented with MG (LAGE+MG). Wild-type EC and sh-mRNA-AGER1(+) EC, but not AGER1(+) EC, had high NOX p47(phox) and gp91(phox) activity, superoxide anions, and NF-kappaB p65 nuclear translocation in response to MG and N(epsilon)-carboxymethyl-lysine. These events involved epidermal growth factor receptor-dependent PKC-delta redox-sensitive Tyr-311 and Tyr-332 phosphorylation and were suppressed in AGER1(+) ECs and enhanced in sh-mRNA-AGER1(+) ECs. Aortic ROS, PKC-delta Tyr-311, and Tyr-332 phosphorylation, NOX expression, and nuclear p65 in older LAGE+MG mice were significantly increased above that in age-matched LAGE mice, which had higher levels of AGER1. In conclusion, circulating AGEs induce NADPH-dependent ROS generation in vascular aging in both in vitro and in vivo models. Furthermore, AGER1 provides protection against AGE-induced ROS generation via NADPH.