MCP-induced protein 1 suppresses TNFα-induced VCAM-1 expression in human endothelial cells

Endothelial inflammation plays a critical role in the development and progression of cardiovascular disease, albeit the mechanisms need to be fully elucidated. We here report that treatment of human umbilical vein endothelial cells (HUVECs) with tumor necrosis factor (TNF) α substantially increased the expression of MCP-induced protein 1 (MCPIP1). Overexpression of MCPIP1 protected ECs against TNFα-induced endothelial activation, as characterized by the attenuation in the expression of the adhesion molecule VCAM-1 and monocyte adherence to ECs. Conversely, small interfering RNA-mediated knock down of MCPIP1 increased the expression of VCAM-1 and monocytic adherence to ECs. These studies identified MCPIP1 as a feedback control of cytokines-induced endothelial inflammation.     

Ablation of NG2 proteoglycan leads to deficits in brown fat function and to adult onset obesity

Obesity is a major health problem worldwide. We are studying the causes and effects of obesity in C57Bl/6 mice following genetic ablation of NG2, a chondroitin sulfate proteoglycan widely expressed in progenitor cells and also in adipocytes. Although global NG2 ablation delays early postnatal adipogenesis in mouse skin, adult NG2 null mice are paradoxically heavier than wild-type mice, exhibiting larger white fat deposits. This adult onset obesity is not due to NG2-dependent effects on CNS function, since specific ablation of NG2 in oligodendrocyte progenitors yields the opposite phenotype; i.e. abnormally lean mice. Metabolic analysis reveals that, while activity and food intake are unchanged in global NG2 null mice, O(2) consumption and CO(2) production are decreased, suggesting a decrease in energy expenditure. Since brown fat plays important roles in regulating energy expenditure, we have investigated brown fat function via cold challenge and high fat diet feeding, both of which induce the adaptive thermogenesis that normally occurs in brown fat. In both tests, body temperatures in NG2 null mice are reduced compared to wild-type mice, indicating a deficit in brown fat function in the absence of NG2. In addition, adipogenesis in NG2 null brown pre-adipocytes is dramatically impaired compared to wild-type counterparts. Moreover, mRNA levels for PR domain containing 16 (PRDM16) and peroxisome proliferator-activated receptor γ coactivator (PGC)1-α, proteins important for brown adipocyte differentiation, are decreased in NG2 null brown fat deposits in vivo and NG2 null brown pre-adipocytes in vitro. Altogether, these results indicate that brown fat dysfunction in NG2 null mice results from deficits in the recruitment and/or development of brown pre-adipocytes. As a consequence, obesity in NG2 null mice may occur due to disruptions in brown fat-dependent energy homeostasis, with resulting effects on lipid storage in white adipocytes.     

Low sclerostin levels: a predictive marker of persistent inflammation in ankylosing spondylitis during anti-tumor necrosis factor therapy?

Introduction

Sclerostin levels have been reported to be low in ankylosing spondylitis (AS), but there is no data regarding the possible role of this Wnt inhibitor during anti-tumor necrosis factor (TNF) therapy. The present study longitudinally evaluated sclerostin levels, inflammatory markers and bone mineral density (BMD) in AS patients under anti-TNF therapy.

Methods

Thirty active AS patients were assessed at baseline, 6 and 12 months after anti-TNF therapy regarding clinical parameters, inflammatory markers, BMD and baseline radiographic damage (mSASSS). Thirty age- and sex-matched healthy individuals comprised the control group. Patients'' sclerostin levels, sclerostin binding low-density lipoprotein receptor-related protein 6 (LRP6) and BMD were evaluated at the same time points and compared to controls.

Results

At baseline, AS patients had lower sclerostin levels (60.5 ± 32.7 vs. 96.7 ± 52.9 pmol/L, P = 0.002) and comparable sclerostin binding to LRP6 (P = 0.387) than controls. Improvement of Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI), Ankylosing Spondylitis quality of life (ASQoL) was observed at baseline vs. 6 vs. 12 months (P < 0.01). Concomitantly, a gradual increase in spine BMD (P < 0.001) and a positive correlation between baseline mSASSS and spine BMD was found (r = 0.468, P < 0.01). Inflammatory parameters reduction was observed comparing baseline vs. 6 vs. 12 months (P <0.01). Sclerostin levels progressively increased [baseline (60.5 ± 32.7) vs. 6 months (67.1 ± 31.9) vs. 12 months (72.7 ± 32.3) pmol/L, P <0.001]. At 12 months, the sclerostin levels remained significantly lower in patients compared to controls (72.7 ± 32.3 vs. 96.70 ± 52.85 pmol/L, P = 0.038). Moreover, sclerostin serum levels at 12 months were lower in the 10 patients with high C reactive protein (CRP) (≥ 5 mg/l) compared to the other 20 patients with normal CRP (P = 0.004). Of note, these 10 patients with persistent inflammation also had lower sclerostin serum levels at baseline compared to the other patients (P = 0.023). Univariate logistic regression analysis demonstrated that AS patients with lower sclerostin serum levels had an increased risk to have high CRP at 12 months (odds ratio = 7.43, 95% CI 1.23 to 45.01, P = 0.020) than those with higher sclerostin values.

Conclusions

Persistent low sclerostin levels may underlie continuous inflammation in AS patients under anti-TNF therapy.     

Cell proliferation along vascular islands during microvascular network growth

ABSTRACT: BACKGROUND: Observations in our laboratory provide evidence of vascular islands, defined as disconnected endothelial cell segments, in the adult microcirculation. The objective of this study was to determine if vascular islands are involved in angiogenesis during microvascular network growth. RESULTS: Mesenteric tissues, which allow visualization of entire microvascular networks at a single cell level, were harvested from unstimulated adult male Wistar rats and Wistar rats 3 and 10 days post angiogenesis stimulation by mast cell degranulation with compound 48/80. Tissues were immunolabeled for PECAM and BRDU. Identification of vessel lumens via injection of FITC-dextran confirmed that endothelial cell segments were disconnected from nearby patent networks. Stimulated networks displayed increases in vascular area, length density, and capillary sprouting. On day 3, the percentage of islands with at least one BRDU-positive cell increased compared to the unstimulated level and was equal to the percentage of capillary sprouts with at least one BRDU-positive cell. At day 10, the number of vascular islands per vascular area dramatically decreased compared to unstimulated and day 3 levels. CONCLUSIONS: These results show that vascular islands have the ability to proliferate and suggest that they are able to incorporate into the microcirculation during the initial stages of microvascular network growth.     

COUPLED TRANSPORT OF GLUTAMATE AND SODIUM IN A CEREBELLAR NERVE CELL LINE

The cerebellar nerve cell line ε¹ has a very effective active transport system for glutamate. Glutamate uptake is dependent on extracellular Na⁺ and furthermore, ²²Na⁺ uptake is stimulated by glutamate, indicating that glutamate uptake and Na⁺ uptake are coupled. Two molecules of Na ⁺ are transported for each molecule of glutamate. The K_m for glutamate is found to be 5 × 10^?5M in both the glutamate uptake assay and the ²²Na⁺ uptake assay, providing additional evidence for glutamate-Na⁺ coupling. Pre-incubation with ouabain, which inhibits the Na⁺-K⁺ ATPase, results in a gradual inhibition of glutamate uptake due to the deterioration of the Na⁺ gradient. Tetrodotoxin, however, has no effect on glutamate-induced ²²Na⁺ uptake, showing that this Na⁺ flux does not occur via voltage-dependent Na⁺ channels. Studies on the specificity of the ε¹ glutamate transport system show that it is distinct from systems that transport alanine and glycine. l -Glutamate, d -aspartate, l -cysteate, and l -cysteine sulfinate are able to utilize the transport system efficiently. d -Glutamate, l -homocysteate, N-methyl-d , l -aspartate, and kainic acid are very poor substrates for the glutamate transport system, and in addition do not stimulate ²²Na⁺ uptake. These data allow us to distinguish the glutamate transport system from the glutamate receptor which is known to mediate depolarization in response to all nine of the above compounds. Thus, ε¹ does not have an excitatory glutamate receptor.     

Analysis of non-TIR NBS-LRR resistance gene analogs in <Emphasis Type="Italic">Musa acuminata</Emphasis> Colla: Isolation,RFLP marker development,and physical mapping

Background  

Many commercial banana varieties lack sources of resistance to pests and diseases, as a consequence of sterility and narrow genetic background. Fertile wild relatives, by contrast, possess greater variability and represent potential sources of disease resistance genes (R-genes). The largest known family of plant R-genes encode proteins with nucleotide-binding site (NBS) and C-terminal leucine-rich repeat (LRR) domains. Conserved motifs in such genes in diverse plant species offer a means for isolation of candidate genes in banana which may be involved in plant defence.