HMGB1 is involved in chronic rejection of cardiac allograft via promoting inflammatory-like mDCs

Chronic rejection that leads to diffuse narrowing and occlusion of graft vessels is the most important cause of morbidity and mortality following cardiac transplantation. The role and underlying mechanism of high-mobility group box 1 (HMGB1), as an established inflammatory mediator in acute rejection, remains poorly understood in chronic rejection. Here, we assessed the effects and mechanisms of HMGB1 on the chronic rejection using single MHC Class II-mismatched mouse cardiac transplantation model. It was found that HMGB1 was increased accompanying with the development of chronic rejection, while blockade of HMGB1 with specific neutralizing mAb substantially ameliorated chronic rejection-mediated vasculopathy and fibrosis of allograft, as well as markedly decreased T cell infiltration and production of IL-17A and interferon-gamma in allograft and recipient's spleen. Further, anti-HMGB1 antibody treatment significantly declined the number and frequency of mature dendritic cells (DCs) in allograft and recipient's spleen, especially CD11b(+) Ly6C(high) matured DCs that share the phenotypes with inflammatory-DCs. These findings indicate that HMGB1 contributes to chronic rejection, and HMGB1 blockade may be a novel mean to disrupt the proinflammatory loop after heart transplantation.

Effect of MPO/H2O2/NO(-) system on nitric oxide-mediated modification of TTR amyloid and serum TTR in FAP ATTR Val30Met patients

Amyloid deposits consist of protein fibrils and amorphous material, and this deposition is related to oxidative stress. Previously, we demonstrated the presence of high-density lipoproteins and/or lipids in amyloid deposits of familial amyloid polyneuropathy patients. In this study, the presence of myeloperoxidase (MPO) in amyloid deposits was demonstrated using immunohistochemical staining. In contrast, normal surrounding tissues were consistently negative for MPO. Nitrotyrosine was present in amyloid deposits after being exposed to the MPO/H2O2/NO(-) system by immunohistochemical staining, and the oxide mediated modification of serum transthyretin (TTR) was observed upon exposure to the MPO/H2O2 system using two-dimensional gel electrophoresis and TTR Western blotting. This observation revealed that the TTR amyloid deposits and serum TTR were oxidized by the MPO/H2O2/NO(-) system. Nitric oxide-mediated modification of TTR may play a role in amyloidogenesis in vivo.

Longikaurin A, a natural ent-kaurane, induces G2/M phase arrest via downregulation of Skp2 and apoptosis induction through ROS/JNK/c-Jun pathway in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, and is also highly resistant to conventional chemotherapy treatments. In this study, we report that Longikaurin A (LK-A), an ent-kaurane diterpenoid isolated from the plant Isodon ternifolius, induced cell cycle arrest and apoptosis in human HCC cell lines. LK-A also suppressed tumor growth in SMMC-7721 xenograft models, without inducing any notable major organ-related toxicity. LK-A treatment led to reduced expression of the proto-oncogene S phase kinase-associated protein 2 (Skp2) in SMMC-7721 cells. Lower Skp2 levels correlated with increased expression of p21 and p-cdc2 (Try15), and a corresponding decrease in protein levels of Cyclin B1 and cdc2. Overexpression of Skp2 significantly inhibited LK-A-induced cell cycle arrest in SMMC-7721 cells, suggesting that LK-A may target Skp2 to arrest cells at the G2/M phase. LK-A also induced reactive oxygen species (ROS) production and apoptosis in SMMC-7721 cells. LK-A induced phosphorylation of c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase and P38 MAP kinase. Treatment with, the JNK inhibitor SP600125 prevented LK-A-induced apoptosis in SMMC-7721 cells. Moreover, the antioxidant N-acetylcysteine prevented phosphorylation of both JNK and c-Jun. Taken together, these data indicate that LK-A induces cell cycle arrest and apoptosis in cancer cells by dampening Skp2 expression, and thereby activating the ROS/JNK/c-Jun signaling pathways. LK-A is therefore a potential lead compound for development of antitumor drugs targeting HCC.

S-phase kinase-associated protein 2 knockdown blocks colorectal cancer growth via regulation of both p27 and p16 expression

The objective of this study was to determine the role and mechanism of S-phase kinase-associated protein 2 (Skp2) in colorectal cancer cell proliferation and survival both in vitro and in vivo. Adenoviral vector expressing Skp2 short hairpin RNA was transduced into SW480 cells. The effects of Skp2 on cell cycle and survival were assessed by Flow Cytometry. Cell proliferation was analyzed by MTT assay. The expression of cell cycle regulators p16 and p27 were measured by western blot. In vivo, human colorectal cancer was produced by xenograft of cancer cells in nude mouse. Tumor growth inhibitory rate was calculated to generate growth curve. Tumor growth was monitored by examining proliferating cell nuclear antigen expression, whereas tumor cell apoptosis was detected by TdT-mediated dUTP nick-end labeling (TUNEL) staining. Knockdown of Skp2 blocked SW480 tumor cell growth and induced cell apoptosis. Skp2 appeared to be very important for the progression of cell cycle at G1/S phase. In vivo, blockade of Skp2 expression inhibited tumor growth and induced tumor apoptosis. Mechanistically, Skp2 regulated the expression of both p27 and p16 both in vitro and in vivo. The conclusion that we derive from this study is that Skp2 regulates colorectal cancer cell growth by inhibiting the expression of cell cycle regulator p27 and p16.

Expression and purification of GST-FHL2 fusion protein

Escherichia coli is the most widely used host for the production of recombinant proteins. However, most eukaryotic proteins are typically obtained as insoluble, misfolded inclusion bodies that need solubilization and refolding. The interactions between human FHL2 protein and many types of proteins, including structural proteins, kinases, and several classes of transcription factor, have been found to have important roles in a variety of fundamental processes, including arrhythmia, hypertrophy, atherosclerosis, and angiogenesis. To achieve high-level expression of soluble recombinant human FHL2 protein in E. coli, we have constructed a recombinant expression plasmid, pGEX-4T-1-FHL2, in which we merged FHL2 cDNA with the glutathione S-transferase (GST) coding sequence downstream of the tac inducible promoter. Using this plasmid, we have achieved high expression of soluble FHL2 as a GST fusion protein in E. coli BL21. We have used the engineered plasmid (pGEX-4T-1-FHL2) and the modified E. coli strain to overcome the problem of removing the GST moiety while expressing soluble FHL2. Our results show that: 1) the recombinant plasmid was successfully constructed. Sequencing results showed that FHL2 and GST are in the same reading frame; 2) at 23°C, soluble GST-FHL2 fusion protein was highly expressed after induction with 0.1 mM IPTG; and 3) GST-FHL2 can be detected by Western blotting using mouse monoclonal anti-GST antibody. Our data are the first to show that high yields of soluble FHL2 tagged with GST can be achieved in E.coli.

Complete genome analysis of a Haemophilus parasuis serovar 12 strain from China

Haemophilus parasuis is the etiological agent of Glässer's disease in pigs and 15 standard serovars were identified. The widespread disease causes great economic loss in the swine industry worldwide. Aiming to investigate the differences in genome composition and functions among various strains, a highly virulent strain ZJ0906 of H. parasuis serovar 12 from China was analyzed and compared with serovar 5 SH0165. Strain ZJ0906 genome is 2,324,740 base pairs with 40.06% genomic GC content. It contains 2,484 open reading frames (ORF) predicted by Glimmer 3.02, of which 2,352 (∼94.7%) were annotated by NCBI nr blast, 1,745 by COG database and 1,829 by KEGG database. 109 potential virulence factors were annotated in strain ZJ0906 and 3 of which are potentially related to antibiotic resistance. Strain ZJ0906 genome is ∼55 kilobases longer than SH0165 genome, with an extra 211 predicted ORFs. VFDB, ARDB, and PAIDB blast searches showed that ZJ0906 and SH0165 shared a nearly identical panel of potential virulence factors, drug resistant genes and four PAI-like regions which showed high homology to Enterococcus, Escherichia and Salmonella. Synteny analysis showed that gene rearrangements are frequent between the two strains, which may lead to variations in pathogenicity and cross-protection among serovars. KEGG pathway analyses showed strain ZJ0906 shared similar metabolic pathways to strain SH0165. Molecular identification of these genomic elements and potential virulence factors pave the way to the better understanding of mechanisms underlying metabolic capabilities and pathogenicity of H. parasuis and prospective vaccine targets besides the widely used method of inactivated bacteria.

Inhibitory effect of components from Streptomyces species on alpha-glucosidase and alpha-amilase of different origin

The search for the effective and safe a-glucosidase and alpha-amylase inhibitors from Actinomycetaceae being antidiabetic agents is actual problem. Twenty one Streptomyces spp. of soil samples collected from different places of China were screened for the ability to produce this kind of inhibitory activities. Fermentation broth of isolated strains had absorbance between 350-190 nm. The Streptomyces strains PW003, ZG636, and ZG731 were characterized by special absorption at 280, 275, and 400 nm, respectively. Ten of the collected actinomycete strains had the ability to inhibit alpha-glucosidase or/and alpha-amylase and the fermentation broth of the same strain had inhibitory activity varied greatly depending on the enzyme source. In the process to screen the leading compounds used as antidiabetic agents, human alpha-glucosidase and alpha-amylase were revealed as the best used in trail compared with the same enzymes from other sources. Active alpha-glucosidase inhibitor was isolated from Streptomyces strain PW638 fermentation broth and identified as acarviostatin 103 by MS and N MR spectrometry. Its IC50 value was 1.25 and 12.23 microg/mL against human intestinal N-terminal maltase-glucoamylase and human pancreatic alpha-amylase, respectively.

Biphasic airway-lung response to anaphylactic shock in Brown Norway rats

Bronchospasm may be part of the response to systemic anaphylaxis in humans. The anaphylactic shock has been characterized in allergic rats, but little data are available on the concurrent changes in airway-lung mechanics. The aim was to describe the respiratory resistance (Rrs) and reactance (Xrs) response to ovalbumin (OVA) induced systemic anaphylaxis in allergic rats. Thirty five anesthetized and mechanically ventilated Brown Norway rats were randomly allocated to OVA (n=20) or vehicle (n=15) sensitization and provocation. Rrs and Xrs were obtained by the forced oscillation technique at 20 Hz. Allergic rats showed dramatic and reproducible concurrent Rrs peak and Xrs through within 4 min of OVA injection (p<0.0001). Thereafter, Rrs returned to baseline while Xrs remained significantly more negative (p<0.0001). It is concluded that systemic anaphylaxis in allergic rats is associated with severe early acute inhomogeneous bronchoconstriction followed by pulmonary interstitial/small airspace edema. The model may be of interest to assess treatments targeting the associated bronchoconstriction and/or airway vascular leakage.

Improved post-prandial ghrelin response by nateglinide or acarbose therapy contributes to glucose stability in Type 2 diabetic patients

BACKGROUND

Recent studies highlight an important role of ghrelin in glucose homeostasis, while the association between ghrelin regulation and glucose fluctuation is unclear.

AIM

We compared the effects of two postprandial hypoglycemic agents on ghrelin response and determined the contribution of ghrelin response to glucose stability in Type 2 diabetic (T2DM) patients.

SUBJECTS AND METHODS

Forty newly- diagnosed T2DM patients were randomly allocated to receive nateglinide or acarbose for 4 weeks, with twenty body mass index (BMI)-matched normoglycemic subjects as controls. Mean glucose values and daily average glucose excursion were assessed using continuous glucose monitoring system. Serum ghrelin levels were determined by enzyme-linked immunosorbent assay.

RESULTS

T2DM patients had similar fasting ghrelin levels (p=0.546), while their postprandial ghrelin suppressions at 30 min and 120 min were reduced as compared to BMI-matched normoglycemic controls (p<0.01). Both nateglinide and acarbose increased post-prandial ghrelin suppression at 120 min and reduced ghrelin area under the curve (AUCGHRL) (p<0.05), while only nateglinide increased postprandial ghrelin suppression at 30 min (p<0.01), which was positively correlated with the increased early-phase insulin secretion by 4 weeks of nateglinide therapy (r=0.48, p=0.05). The decrease in AUCGHRL was positively correlated with the decrease in daily average glucose excursion and mean glucose values either by 4 weeks of nateglinide or acarbose therapy (p<0.05).

CONCLUSIONS

Both nateglinide and acarbose increase post-prandial ghrelin suppression. Improved ghrelin regulation is most likely to play a role in glucose stability in T2DM patients with nateglinide or acarbose therapy.

A PEGylated fluorescent turn-on sensor for detecting fluoride ions in totally aqueous media and its imaging in live cells

Owing to the considerable significance of fluoride anions for health and environmental issues, it is of great importance to develop methods that can rapidly, sensitively and selectively detect the fluoride anion in aqueous media and biological samples. Herein, we demonstrate a robust fluorescent turn-on sensor for detecting the fluoride ion in a totally aqueous solution. In this study, a biocompatible hydrophilic polymer poly(ethylene glycol) (PEG) is incorporated into the sensing system to ensure water solubility and to enhance biocompatibility. tert-Butyldiphenylsilyl (TBDPS) groups were then covalently introduced onto the fluorescein moiety, which effectively quenched the fluorescence of the sensor. Upon addition of fluoride ion, the selective fluoride-mediated cleavage of the Si-O bond leads to the recovery of the fluorescein moiety, resulting in a dramatic increase in fluorescence intensity under visible light excitation. The sensor is responsive and highly selective for the fluoride anion over other common anions; it also exhibits a very low detection limit of 19 ppb. In addition, this sensor is operative in some real samples such as running water, urine, and serum and can accurately detect fluoride ions in these samples. The cytotoxicity of the sensor was determined to be Grade I toxicity according to United States Pharmacopoeia and ISO 10993-5, suggesting the very low cytotoxicity of the sensor. Moreover, it was found that the senor could be readily internalized by both HeLa and L929 cells and the sensor could be utilized to track fluoride level changes inside the cells.

Cathepsin B may be a potential biomarker in cervical cancer

Cathepsin B is a protease which is able to digest extracellular matrix. It is currently unknown whether cathepsin B plays a role in cervical cancer development and progression. With Q-PCR and Western blotting, we observed cathepsin B expression in cervical cancer cell line Hela cells. After the gene was silenced in HeLa cells with SiRNA, we confirmed that cathepsin B expressions at both mRNA and protein levels were significantly reduced. At the same time, cell proliferation, migration and invasion of the HeLa cells were significantly decreased compared to control cells. In addition, a significant regression of tumor growth in nude mice which received the siRNA targeted cathepsin B HeLa cells was observed. We further studied the expression of cathepsin B in a series of 169 clinical samples, including 56 invasive cervical squamous carcinoma, 85 CINs and 28 normal cervical tissues. It was found that cathepsin B expression in invasive carcinomas was significantly higher than that in the CINs and normal tissues (P<0.01). In addition, cathepsin B expression in the invasive carcinomas was positively correlated to tumor invasion depth and lymphatic metastasis. Our results indicate that cathepsin B may be a potential biomarker for further strategical clinical studies in cervical cancer.

Gene mapping and mutation screening in candidate genes in a Chinese family of autosomal dominant retinitis pigmentosa

We wanted to find the gene defect in a Chinese pedigree with autosomal dominant form of retinitis pigmentosa (ADRP). A small Chinese family with retinitis pigmentosa was collected. The genetic analysis of the family suggested an autosomal dominant pattern. Microsatellite (STR) markers tightly linked to candidate genes for ADRP were selected for linkage analysis. We got a maximum LOD score of 0.87 between markers D19S210 and D19S418. Precursor mRNA-processing factor (PRPF) 31, 3, 8, rhodopsin (RHO), peripherin 2 (PRPH2 or RDS), rod outer segment protein 1 (ROM1), neural retina leucine zipper (NRL), cone-rod homeobox-containing (CRX), inosine-5-prime-monophosphate dehydrogenase, type I (IMPDH1) and retinitis pigmentosa 1 (RPI) were amplified by polymerase chain reaction (PCR) and screened by direct sequencing. One new sequence variation was found. It was the missence mutation c.148G > C (D50H) occurred in exon 1 of RDS gene which existed in all the effected individuals and one unaffected family member. The DNA sequence variation didn't cosegregate with the RP disease. We considered this transition was one new polymorphism which we speculate involved in the pathogenesis of ADRP and increased the risk of ADRP. Further study should be conducted to confirm the causative gene of this family.

Laser Synthesis of Iron Nitride Nanoparticles from Pyrolysis of Fe(CO)5-NH3 System

By vapor-phase pyrolysis of Fe(CO) 5 and NH3 induced by CW CO2 laser, γ'-Fe4N and ε- Fe3N nanoparticles(≤35nm) were prepared in Ar and N2 atmospheres. In Ar, γ'-Fe4N accompanied by a little α-Fe was formed at low temperatures below 650°C, while higher temperatures favored the formation of γ-Fe. In N2 atmospheres, a mixture of Fe4N and Fe3N nanoparticles were obtained at high temperatures. In addition, the influences of synthesis parameters on the structure, morphology and magnetic properties of the nanoparticles were discussed.

Silicate Formation at the Interface of high-k dielectrics and Si(001) Surfaces

The composition and chemical bonding of the first atoms across the interface between Si(001) and the dielectric determine the quality of dielectric gate stacks. An analysis of that hidden interface is a challenge as it requires both, high sensitivity and elemental and chemical state information. We used SR based photoelectron spectroscopies and, in particular, X-ray absorption spectroscopy in total electron yield and total fluorescence yield at the Si2p and the O1s edges to address that issue. We report on results of Hf-oxide prepared by ALD and compare to Pr2O3 / Si(001), and compare the two to the SiO2 / Si(001) system as a reference. For both, Hf-oxide and Pr-oxide thin films we find evidence for the silicate formation at the interface as derived from the characteristic features at the Si2p and the O1s edges.