Protective effects of bone morphogenetic protein 7 against amyloid-beta induced neurotoxicity in PC12 cells

Bone morphogenetic protein 7 (BMP7) has neuroprotective effects against ischemia, oxidation stress, and lipopolysaccharide, but its role on amyloid-beta (Aβ)-induced neurotoxicity in Alzheimer's disease (AD) and the underlying mechanisms remain unclear. In this study, we exposed PC12 cells to Aβ25-35 for 26 h to induce neurotoxicity, and added exogenous BMP7 at 2 h to observe the neuroprotective effects. The protective mechanisms involved, mostly related to inhibition of cell apoptosis and oxidation stress, were analyzed. In rat in vivo experiments, we bilaterally injected Aβ1-40 into the basal forebrain to simulate neuropathological processes in AD, performed the Morris water maze test to evaluate the effect of Aβ on spatial learning and memory, and explored the change of endogenous BMP7 expression in the brain. The present study demonstrated that BMP7 prevented neuronal injuries in PC12 cells induced by Aβ25-35, including cell apoptosis and morphological impairment of dendrites as well as oxidation stress. BMP7 treatment significantly protected PC12 cells against Aβ25-35-induced injury and inhibited the increasing content of the Bax gene and the decreasing activities of superoxide dismutase (SOD). Aβ1-40 bilaterally injected into the rat basal forebrain obviously inhibited the rat's spatial learning ability and memory, and significantly induced downregulation of endogenous BMP7 in the basal forebrain while upregulating it in the hippocampus. Our results suggest that BMP7 has neuroprotective effects against Aβ, which may be mediated through inhibition of Bax gene expression during cell apoptosis and elevation of SOD activities during the oxidative stress response. On the other hand, endogenous BMP7 may have a potential self-modulation capacity through negative feedback between the region of the basal forebrain and the hippocampus as a protective cytokine.

Deletion of the betaine-GABA transporter (BGT1; slc6a12) gene does not affect seizure thresholds of adult mice

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian brain. Once released, it is removed from the extracellular space by cellular uptake catalyzed by GABA transporter proteins. Four GABA transporters (GAT1, GAT2, GAT3 and BGT1) have been identified. Inhibition of the GAT1 by the clinically available anti-epileptic drug tiagabine has been an effective strategy for the treatment of some patients with partial seizures. Recently, the investigational drug EF1502, which inhibits both GAT1 and BGT1, was found to exert an anti-convulsant action synergistic to that of tiagabine, supposedly due to inhibition of BGT1. The present study addresses the role of BGT1 in seizure control and the effect of EF1502 by developing and exploring a new mouse line lacking exons 3-5 of the BGT1 (slc6a12) gene. The deletion of this sequence abolishes the expression of BGT1 mRNA. However, homozygous BGT1-deficient mice have normal development and show seizure susceptibility indistinguishable from that in wild-type mice in a variety of seizure threshold models including: corneal kindling, the minimal clonic and minimal tonic extension seizure threshold tests, the 6Hz seizure threshold test, and the i.v. pentylenetetrazol threshold test. We confirm that BGT1 mRNA is present in the brain, but find that the levels are several hundred times lower than those of GAT1 mRNA; possibly explaining the apparent lack of phenotype. In conclusion, the present results do not support a role for BGT1 in the control of seizure susceptibility and cannot provide a mechanistic understanding of the synergism that has been previously reported with tiagabine and EF1502.

Contribution of the epithelial-mesenchymal (EMT) phenotype to the sensitivity of colorectal cancer cell lines to the p21-activated kinase inhibitor, PF-3758309

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Background: Increased expression of p21–activated kinase (PAK) family proteins has been observed in a range of malignancies including those of breast, ovarian, colorectal (CRC), and pancreatic origin. PAK (PAK 1-6) proteins are critical mediators of cell proliferation, motility, transcription, and translation. In initial studies, we demonstrated that the PAK4 inhibitor, PF-3758309, exhibited robust single agent efficacy against selected CRC cell lines, with IC50s of less than 0.015 uM, whereas some cell lines were relatively resistant to the agent, with IC50s of greater than 1 uM. In subsequent gene array analyses, CRC cell lines sensitive or resistant to PF-3758309 exhibited overexpression of core genes associated with a mesenchymal or epithelial phenotype, respectively. Thus, the goal of this study was to assess the functional consequences of altering the expression of EMT-associated genes and to seek rational combination partners in CRC.

Methods: CRC cell lines that were sensitive to PF-3758309 (IC50=0.015 uM) were transfected with selected short hairpin- (sh)RNAs or micro-(mi)RNAs that are known to regulate EMT. Semi-quantitative RT-PCR and immunoblotting were performed to confirm target knockdown. The transfected cell lines were then exposed to increasing concentrations of PF-3758309 to determine the functional role of these genes in conferring responsiveness to PF-3758309.

Results: Sensitive CRC cell lines were transfected with shRNAs to Zeb1, vimentin, and caldesmon, genes that are associated with a mesenchymal phenotype. Interestingly, when the cell lines were exposed to increasing concentrations of PF- 3758309 they demonstrated a ′right shift′ towards a more resistant phenotype. Likewise, transfection with miRNA 200c, a known suppressor of Zeb1, resulted in a similar shift towards resistance.

Conclusions: These data suggest that the EMT phenotype may play a functional role in determining CRC sensitivity to the PAK4 inhibitor PF-3758309, and in addition, a rational combination targeting the epithelial phenotype with epidermal growth factor receptor inhibitors, may be warranted.

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Diagnosis and microsurgery of symptomatic spontaneous spinal epidural hematoma

BACKGROUND

Symptomatic spontaneous spinal epidural hematoma (SSEH) is an uncommon cause of cord compression that needs emergent treatment. Without effective management of the symptomatic SSEH, irreversible severe spinal injury would be possible.

OBJECTIVES

We aimed to investigate the diagnosis and surgical management of symptomatic SSEH.

METHODS

Five cases of symptomatic SSEH with favorable neurological recovery after emergent microsurgery were prospectively analysed.

RESULTS

The main clinical presentations were root pain and palsy. The main manifestations of MRI were long-segment epidural lesions of high intensity on T1- and T2-weighted images without enhancement. Laminectomy via posterior approach and hematoma removal were undergone for all patients. All patients achieved full neurological recovery without complications.

CONCLUSIONS

MRI manifestation assisted with the main clinical symptoms may aid the preoperative diagnosis of SSEH, and the delay in obtaining preoperative Digital subtraction angiography is worthwhile, especially for those with progressive neurological deterioration.

Iron-Stimulated N(2) Fixation and Growth in Natural and Cultured Populations of the Planktonic Marine Cyanobacteria Trichodesmium spp

In light of recent proposals that iron (Fe) availability may play an important role in controlling oceanic primary production and nutrient flux, its regulatory impact on N(2) fixation and production dynamics was investigated in the widespread and biogeochemically important diazotrophic, planktonic cyanobacteria Trichodesmium spp. Fe additions, as FeCl(3) and EDTA-chelated FeCl(3), enhanced N(2) fixation (nitrogenase activity), photosynthesis (CO(2) fixation), and growth (chlorophyll a production) in both naturally occurring and cultured (on unenriched oligotrophic seawater) Trichodesmium populations. Maximum enhancement of these processes occurred under FeEDTA-amended conditions. On occasions, EDTA alone led to enhancement. No evidence for previously proposed molybdenum or phosphorus limitation was found. Our findings geographically extend support for Fe limitation of N(2) fixation and primary production to tropical and subtropical oligotrophic ocean waters often characterized by Trichodesmium blooms.

The Treg/Th17 imbalance in patients with idiopathic dilated cardiomyopathy

To assess whether Treg/Th17 balance was broken in patients with idiopathic dilated cardiomyopathy (DCM). We studied 25 patients who were diagnosed as idiopathic DCM (18 men and seven women, mean age 35.6 +/- 5.2) and 25 normal persons (18 men and seven women, mean age 33.8 +/- 4.9). Then, we detected Treg/Th17 functions on different levels including cell frequencies, related cytokine secretion and key transcription factors in patients with idiopathic DCM and controls. The results demonstrated that patients with idiopathic DCM revealed significant increase in peripheral Th17 number, Th17-related cytokines (IL-17, IL-6, IL-23) and transcription factor (RORgammat) levels and obvious decrease in Treg number, Treg-related cytokines (TGF-beta1 and IL-10) and transcription factor (Foxp3) levels when compared to normal persons. Results indicated that Treg/Th17 functional imbalance existed in patients with idiopathic DCM, suggesting a potential role for Treg/Th17 imbalance in the development of idiopathic DCM.

The genetics of NOD-like receptors in Crohn's disease

The first Crohn's disease (CD) susceptibility gene identified was CARD15, which is a member of the emerging NOD-like receptor (NLR) family. These function as intracellular cystosolic pattern recognition receptors (PRRs) and play a central role in the innate immune response. We studied other members of the NLR family using a gene-wide haplotype tagging approach in a well-characterised collection of 547 CD patients and 465 controls. Four single nucleotide polymorphisms (SNPs) in NLRP3 had P values < 0.05 and are in high linkage disequilibrium (LD) with each other (r(2) > 0.90 for all four SNPs). rs4925648 and rs10925019 were the most strongly associated with CD susceptibility (P = 0.001, odds ratio (OR) 1.62, 95% CI 1.2-2.18; and P = 6.5 x 10(-4), OR 1.65, 95% CI 1.23-2.19, respectively). rs1363758 located in NLRP11 was associated with CD susceptibility [P = 0.002 (1.64, 1.19-2.25)], which was weakly confirmed in an independent case-cohort collection on joint analysis [P = 0.05, (1.28, 1-1.64)]. On sub-phenotype analysis, an interesting association between NLRP1 and skin extra-intestinal manifestations and colonic, inflammatory CD was identified. None of these results was replicated in the Wellcome Trust Case Control Consortium study and therefore need replication in a further large cohort.

The allogeneic but not syngeneic dendritic cells effectively generated regulatory T cells from total CD4+ population without exogenous cytokines

Dendritic cells (DC) play a critical role in both the expansion of natural regulatory T cells (nTreg) and conversion of induced Treg (iTreg) from their precursors. In the present study, we evaluated the potential of DC to generate Treg from total CD4(+) population which contains both nTreg and the precursors, and found that allogeneic (allo-DC) but not syngeneic DC (syn-DC) could effectively generated Foxp3(+) Treg from total CD4(+) population in the absence of exogenous cytokines. Compared with freshly purified CD4(+) T cells, allo-DC-stimulated CD4(+) T cells showed increased percentage of CD4(+)CD25(+)Foxp3(+) Treg by 5-7-folds while syn-DC-stimulated CD4(+) T cells did not. Furthermore, we demonstrated that the significant amounts of endogenous IL-2 and TGF-beta, at least partially, contributed to the expansion of nTreg and conversion of iTreg in this cocultural system, respectively. Importantly, similar to nTreg, these allo-DC-generated Treg were capable of suppressing T cell response in vitro. Thus, our research provides a novel and efficient strategy for generation of Treg from total CD4(+) population.

Hepatitis B virus protein preS2 potentially promotes HCC development via its transcriptional activation of hTERT

BACKGROUNDS AND AIMS

Telomerase is significantly reactivated in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). Our previous studies showed that the transactivation unit of HBV surface (S) gene, preS2, could upregulate human telomerase reverse transcriptase (hTERT) expression and telomerase activity of HepG2 cells. Here, we aim to explore the functions, and the underlying mechanisms, of this preS2-mediated hTERT upregulation during HCC development.

METHODS

An antisense blocking assay was performed on HBV-integrated HepG2.2.15 cells. The expression of hTERT was examined in clinical samples to test the role of the preS2-mediated hTERT upregulation in HCC development in vivo. In order to explore the mechanisms of preS2-mediated hTERT upregulation, co-transfection, reporter assays and electrophoretic mobility shift assays (EMSA) were performed.

RESULTS

Blocking preS2 expression reduced hTERT expression, telomerase activity, cell proliferation and tumorigenicity of HepG2.2.15. A region located between -349 and -329 bp upstream of the transcription initiation site of hTERT was identified as responsible for the preS2-mediated effect. preS2 interacted with the preS2-responsible region (PRR) and activated the hTERT promoter. Importantly, hTERT was also highly expressed in preS2-positive human HCC samples. All these findings strongly suggest that preS2 may promote HCC development via hTERT activation.

CONCLUSIONS

HBV protein preS2 upregulates hTERT via the PRR element in promoting HCC development.

Microstructure, nickel suppression and mechanical characteristics of electropolished and photoelectrocatalytically oxidized biomedical nickel titanium shape memory alloy

A new surface modification protocol encompassing an electropolishing pretreatment (EP) and subsequent photoelectrocatalytic oxidation (PEO) has been developed to improve the surface properties of biomedical nickel titanium (NiTi) shape memory alloy (SMA). Electropolishing is a good way to improve the resistance to localized breakdown of NiTi SMA whereas PEO offers the synergistic effects of advanced oxidation and electrochemical oxidation. Our results indicate that PEO leads to the formation of a sturdy titania film on the EP NiTi substrate. There is an Ni-free zone near the top surface and a graded interface between the titania layer and NiTi substrate, which bodes well for both biocompatibility and mechanical stability. In addition, Ni ion release from the NiTi substrate is suppressed, as confirmed by the 10-week immersion test. The modulus and hardness of the modified NiTi surface increase with larger indentation depths, finally reaching plateau values of about 69 and 3.1GPa, respectively, which are slightly higher than those of the NiTi substrate but much lower than those of a dense amorphous titania film. In comparison, after undergoing only EP, the mechanical properties of NiTi exhibit an inverse change with depth. The deformation mechanism is proposed and discussed. Our results indicate that surface modification by dual EP and PEO can notably suppress Ni ion release and improve the biocompatibility of NiTi SMA while the surface mechanical properties are not compromised, making the treated materials suitable for hard tissue replacements.

Prognostic value of different B symptoms in upper aerodigestive tract NK/T-cell lymphoma

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Background: Extranodal NK/T-cell lymphoma (ENKL) is a rare disease originated from NK or toxic T cells. ENKL arising from the upper aerodigestive tract (UNKTL) is a newly recognized subtype and commonly presents with B symptoms. This study is to investigate the prognostic value of different B symptoms in UNKTL. Methods: UNKTL cases with detailed clinical, pathological and prognostic data in our center since 2001 to 2007 were retrospectively analyzed with the major study endpoint of overall survival (OS). Central pathological review was performed. Survival curves were estimated by Kaplan-Meier method and tested by Log Rank method. Statistically significant factors in univariate analysis were then included in multivariate analysis. B symptoms were defined as fever, night sweat and weight loss according to the Ann Arbor Cotswolds meeting. The predictive values of survival for each type of B symptoms were studied independently. Results: 172 cases of UNKTL with a median follow-up duration of 27.4 months were included. 45 ladies and 127 gentlemen had a median age of 43 years. 98 cases were Ann Arbor stage I, 54 were stage II and the remaining 20 cases were stage III or IV. About half of the patients present B symptoms: 82 had fever, 5 had night sweat and 6 present weight loss. Totally 18 patients had ECOG PS larger than 1. The 5-year OS rate of the whole group is 41.8%. Patients with persistent fever before treatment indicated a poor outcome in the univariate analysis (p=.033) and its prognostic value was also confirmed by the Cox regression (p=.030) whereas those of night sweat and weight loss were not (p= .960 and .824 respectively). Conclusions: B symptoms were common in UNKTL patients. Our data suggested that only fever among the three types of B symptoms was independent prognostic factor for UNKTL but it still needs further confirmation.

No significant financial relationships to disclose.

XPS and biocompatibility studies of titania film on anodized NiTi shape memory alloy

A dense titania film is fabricated in situ on NiTi shape memory alloy (SMA) by anodic oxidation in a Na(2)SO(4) electrolyte. The microstructure of the titania film and its influence on the biocompatibility of NiTi SMA are investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICPMS), hemolysis analysis, and platelet adhesion test. The results indicate that the titania film has a Ni-free zone near the surface and can effectively block the release of harmful Ni ions from the NiTi substrate in simulated body fluids. Moreover, the wettability, hemolysis resistance, and thromboresistance of the NiTi sample are improved by this anodic oxidation method.