Sequential activation of JAKs, STATs and xanthine dehydrogenase/oxidase by hypoxia in lung microvascular endothelial cells

Xanthine dehydrogenase/oxidase (XDH/XO) is associated with various pathological conditions related to the endothelial injury. However, the molecular mechanism underlying the activation of XDH/XO by hypoxia remains largely unknown. In this report, we determined whether the Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) signaling pathway is involved in hypoxia-induced activation of XDH/XO in primary cultures of lung microvascular endothelial cells (LMVEC). We found that hypoxia significantly increased interleukin 6 (IL6) production in a time-dependent manner in LMVEC. Hypoxia also markedly augmented phosphorylation/activation of JAKs (JAK1, JAK2 and JAK3) and the JAK downstream effectors STATs (STAT3 and STAT5). Hypoxia-induced activation of STAT3 was blocked by IL6 antibodies, the JAK inhibitor AG490 and the suppressor of cytokine signaling 3 (SOCS3), implying that hypoxia-promoted IL6 secretion activates the JAK/STAT pathway in LMVEC. Phosphorylation and DNA-binding activity of STAT3 were also inhibited by the p38 MAPK inhibitor SB203580 and the phosphatidylinositol 3-kinase inhibitor LY294002, suggesting that multiple signaling pathways involved in STAT activation by hypoxia. Importantly, hypoxia promoted XDH/XO activation in LMVEC, which was markedly reversed by inhibiting the JAK-STAT pathway using IL6 antibodies, AG490 and SOCS3. These data demonstrated that JAKs, STATs and XDH/XO were sequentially activated by hypoxia. These data provide the first evidence indicating that the JAK-STAT pathway is involved in hypoxia-mediated XDH/XO activation in LMVEC.

Increased asynchronous release and aberrant calcium channel activation in amyloid precursor protein deficient neuromuscular synapses

Despite the critical roles of the amyloid precursor protein (APP) in Alzheimer's disease pathogenesis, its physiological function remains poorly established. Our previous studies implicated a structural and functional activity of the APP family of proteins in the developing neuromuscular junction (NMJ). Here we performed comprehensive analyses of neurotransmission in mature neuromuscular synapse of APP deficient mice. We found that APP deletion led to reduced paired-pulse facilitation and increased depression of synaptic transmission with repetitive stimulation. Readily releasable pool size and total releasable vesicles were not affected, but probability of release was significantly increased. Strikingly, the amount of asynchronous release, a measure sensitive to presynaptic calcium concentration, was dramatically increased, and pharmacological studies revealed that it was attributed to aberrant activation of N- and L-type Ca(2+) channels. We propose that APP modulates synaptic transmission at the NMJ by ensuring proper Ca(2+) channel function.

Prediction of mutations engineered by randomness in H5N1 neuraminidases from influenza A virus

In this proof-of-concept study, we attempt to determine whether the cause-mutation relationship defined by randomness is protein dependent by predicting mutations in H5N1 neuraminidases from influenza A virus, because we have recently conducted several concept-initiated studies on the prediction of mutations in hemagglutinins from influenza A virus. In our concept-initiated studies, we defined the randomness as a cause for mutation, upon which we built a cause-mutation relationship, which is then switched into the classification problem because the occurrence and non-occurrence of mutations can be classified as unity and zero. Thereafter, we used the logistic regression and neural network to solve this classification problem to predict the mutation positions in hemagglutinins, and then used the amino acid mutating probability to predict the would-be-mutated amino acids. As the previous results were promising, we extend this approach to other proteins, such as H5N1 neuraminidase in this study, and further address various issues raised during the development of this approach. The result of this study confirms that we can use this cause-mutation relationship to predict the mutations in H5N1 neuraminidases.

Multiple auras: Clinical significance and pathophysiology

BACKGROUND

Patients with partial epilepsy may report multiple types of aura during their seizures. The significance of the occurrence of multiple auras in the same patient is not known.

METHODS

The clinical and electrophysiologic characteristics of patients with more than one aura type (abdominal, auditory, autonomic, gustatory, olfactory, psychic, somatosensory, and visual auras), evaluated in the Cleveland Clinic epilepsy monitoring unit between 1989 and 2005, were studied.

RESULTS

Thirty-one patients experienced multiple aura types during a seizure. Ninety percent of patients with at least two aura types (n = 31) and 100% percent of patients with at least three aura types (n = 12) had seizures arising from the right/nondominant hemisphere. EEG seizures remained restricted in all patients during their auras. nineteen [corrected] patients had epilepsy surgery with seizure freedom in 53%. Subdural EEG recordings in six patients showed either a march of sequential auras, or in one case, several ictal onset zones resulting in separate isolated auras. Ictal SPECT in six patients with right-sided seizures showed a lack of activation in brainstem structures.

CONCLUSIONS

Most patients who report multiple aura types have localized epilepsy in the nondominant hemisphere, and are good surgical candidates. A common mechanism for multiple auras may be a spreading but restricted EEG seizure activating sequential symptomatogenic zones, but without the ictal activation of deeper structures or contralateral spread to cause loss of awareness and amnesia for the auras.

Arylpropanolamines: Selective β3 agonists arising from strategies to mitigate phase I metabolic transformations

Utilization of N-substituted-4-hydroxy-3-methylsulfonanilidoethanolamines 1 as selective beta(3) agonists is complicated by their propensity to undergo metabolic oxidative N-dealkylation, generating 0.01-2% of a very potent alpha(1) adrenergic agonist 2. A summary of the SAR for this hepatic microsomal conversion precedes presentation of strategies to maintain the advantages of chemotype 1 while mitigating the consequences of N-dealkylation. This effort led to the identification of 4-hydroxy-3-methylsulfonanilidopropanolamines 15 for which the SAR for the unique stereochemical requirements for binding to the beta adrenergic receptors culminated in the identification of the potent, selective beta(3) agonist 15f.

Regulation of anterograde transport of adrenergic and angiotensin II receptors by Rab2 and Rab6 GTPases

Three Rab GTPases, Rab1, Rab2 and Rab6, are involved in protein transport between the endoplasmic reticulum (ER) and the Golgi. Whereas Rab1 regulates the anterograde ER-to-Golgi transport, Rab2 and Rab6 coordinate the retrograde Golgi-to-ER transport. We have previously demonstrated that Rab1 differentially modulates the export trafficking of distinct G protein-coupled receptors (GPCRs). In this report, we determined the role of Rab2 and Rab6 in the cell-surface expression and signaling of alpha(2B)-adrenergic (alpha(2B)-AR), beta(2)-AR and angiotensin II type 1 receptors (AT1R). Expression of the GTP-bound mutant Rab2Q65L significantly attenuated the cell-surface expression of both alpha(2B)-AR and beta(2)-AR, whereas the GTP-bound mutant Rab6Q72L selectively inhibited the transport of beta(2)-AR, but not alpha(2B)-AR. Similar results were obtained by siRNA-mediated selective knockdown of endogenous Rab2 and Rab6. Consistently, Rab2Q65L and Rab2 siRNA inhibited alpha(2B)-AR and beta(2)-AR signaling measured as ERK1/2 activation and cAMP production, respectively, whereas Rab6Q72L and Rab6 siRNA reduced signaling of beta(2)-AR, but not alpha(2B)-AR. Similar to the beta(2)-AR, AT1R expression at the cell surface and AT1R-promoted inositol phosphate accumulation were inhibited by Rab6Q72L. Furthermore, the nucleotide-free mutant Rab6N126I selectively attenuated the cell-surface expression of beta(2)-AR and AT1R, but not alpha(2B)-AR. These data demonstrate that Rab2 and Rab6 differentially influence anterograde transport and signaling of GPCRs. These data also provide the first evidence indicating that Rab6-coordinated retrograde transport selectively modulates intracellular trafficking and signaling of GPCRs.

The function of RNAi in plant development

The morphological phenotype of mutations in genes required for posttranscriptional gene silencing (PTGS) or RNA interference (RNAi) in Arabidopsis demonstrates that this process is critical for normal development. One way in which RNAi contributes to gene regulation is through its involvement in the biogenesis of trans-acting small interfering RNAs (siRNAs). These endogenous siRNAs are derived from noncoding transcripts that are cleaved by a microRNA (miRNA) and mediate the silencing of protein-coding transcripts. Some protein-coding genes are also subject to miRNA-initiated transitive silencing. Several developmentally important transcription factors regulated by these silencing mechanisms have been identified.

Clinical significance of Cdh1-Skp2 cascade in breast cancer

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Background: Skp2 (S-phase kinase-associated protein 2) is substrate-recognizing subunit of an ubiquitin E3 ligase SCF (Skp1, Cullin and F-box) complex and has a major role in p27 regulation. Overexpression of Skp2 is frequently seen in human tumors, often correlating with poor prognosis. Anaphase-promoting complex/cyclosome (APC/C) is another most prominent ubiquitin E3 ligase in cell cycle control, and its function is tightly controlled by activating subunit Cdh1 (Fizzy-related). APC-Cdh1 complex is supposed to be involved in Skp2 proteolysis and have essential role for S phase entry, however clinical significance of Cdh1 have not evaluated yet. Herein we examined the significance of Cdh1 in breast cancer. Methods: Firstly, MCF7 human breast cancer cells and MCF10A normal breast epithelial cells were analyzed in vitro and in vivo. Thereafter, using tissue microarray, we evaluate the expression profile of Cdh1, Skp2 and p27 in both breast cancer and normal breast epithelial tissue. Moreover, clinicopathological significance (age, tumor size, lymph node metastasis, distant metastasis, histological grade, and stage) of Cdh1 was analyzed from 126 breast cancer patients. Chi square-test, Fisher's exact test were used for statistical analysis of immunostaining results and clinicopathological data. p<0.05 was considered statistically significant. Results: Overexpression of Cdh1 induced attenuation of Skp2 and increased p27 protein expression, resulted in growth suppression. Moreover, knockdown of Cdh1 promoted higher Skp2 expression and S-phase population, reduced p27 and consequently induced cell transformation and proliferation in vitro and in vivo. Tissue microarray results appeared that positive Cdh1 and p27 was more frequently seen in normal breast tissue and statistically significant. On the other hand, Skp2 was less in normal tissue. Furthermore, Cdh1 positive breast cancer was more frequently seen in low histological grade tumors and statistically significant (p=0.04). Conclusions: Skp2 protein expression is regulated by Cdh1 in breast cancer. Cdh1 expression could be possible novel biomarker in patient with breast cancer.

No significant financial relationships to disclose.

The effect of antisense oligodeoxynucleotides targeting Aurora A kinase on cell proliferation and chemosensitivity to paclitaxel in human lung cancer cell line A549

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Background: Aurora kinases representing a family of evolutionarily conserved mitotic serine/threonine kinases have been found elevated in lung andenocarcinoma cell line A549. It is suggested that the overexpression of Aurora A contributes to the carcinogenesis, chromosomal instability (CIN), and de-differentiation of lung cancers. To address its possibility as a therapeutic target for lung cancer, we employed the antisense oligodeoxynucleotide (ASODN) technique to inhibit Aurora A expression and investegate its effect on tumor growth and cell cycle of A549, as well as the chemosensitivity of paclitaxel. Methods: Aurora A ASODN was synthesized and transfected into A549 cells by lipofectAMINE 2000.Aurora A mRNA and protein expression were examined by reverse transcription -polymerase chain reaction (RT-PCR) and Western blot respectively.Cell cycle distribution was observed by flow cytometer.MTT assay was used to evaluate cell inhibition ratio before and after transfection. Results: The proliferation of the A549 cells was inhibited by Aurora A ASODN dose and time dependently. It was also observed that the IC50 of A549 cells after 48 hours’ treatment of ASODN was about 300nmol/L and under such circumstances, the Aurora A mRNA and protein expression significantly decreased (P<0.05), along with the induction of accumulation of cells in S phase and the G2-M transition. Furhermore, cell inhibition ratio of the combination of Aurora A ASODN and paclitaxel was higher significantly than paclitaxel(P<0.05) or Aurora A ASODN alone (P<0.05). Conclusions: Inhibition of Aurora A expression can results in the suppression of cell growth and chemosensitizing activity to paclitaxel in human lung cancer cell line A549.

No significant financial relationships to disclose.

Effect of Molting Method and Dietary Energy on Postmolt Performance, Egg Components, Egg Solid, and Egg Quality in Bovans White and Dekalb White Hens During Second Cycle Phases Two and Three

Two experiments of 4 x 2 x 2 factorial arrangements of 4 dietary energy levels, 2 molting methods (feed withdrawal and no salt diet), and 2 strains (Bovans White and Dekalb White) were conducted to determine the effect of dietary energy and molting method on long-term postmolt performance of 2 strains of commercial Leghorns. In experiments 1 and 2, Bovans White hens (n = 576) and Dekalb White hens (n = 576) were randomly divided into 16 treatments (6 replicates of 12 birds per treatment). Experiment 1 lasted from 86 to 96 wk of age, and experiment 2 lasted from 100 to 110 wk of age. Bovans White hens had significantly higher egg production than Dekalb White hens, whereas Bovans White hens had significantly lower egg weight, percentage of eggshell, and egg specific gravity than Dekalb White hens. Based on improved feed conversion, dietary energy of 2,846 kcal of ME/kg appeared to be enough for optimal performance during second cycle phase 2. Based on BW of hens, dietary energy level for optimal performance should be less than 2,936 kcal of ME/kg during second cycle phase 3. There can be no fixed ideal dietary energy level for optimal profits for postmolt egg production. Molting method had no effect on egg production and egg mass during the early and middle stages of the postmolt production period. However, hens molted by feed withdrawal had significantly higher egg production and egg mass during the later stage of the postmolt production period compared with hens molted by a no salt diet. There was no significant difference in egg specific gravity due to molting method. Feeding a no salt diet resulted in reasonable long-term postmolt performance and eggshell quality, rather than optimal performance and eggshell quality.

Blocking the CC chemokine receptor 5 pathway by antisense peptide nucleic acid prolongs islet allograft survival

Chemokines are important regulators in the development, differentiation, and anatomic location of leukocytes. The CC chemokine receptor 5 (CCR5) is the receptor for the proinflammatory chemokines and plays an important role in islet allograft rejection. Peptide nucleic acid (PNA) is a nucleic acid analog in which the sugar phosphate backbone of natural nucleic acid has been replaced by a synthetic peptide backbone. Studies indicate that PNA inhibits both transcription and translation of targeted genes. Fullly major histocompatibility complex (MHC)-mismatched murine islet transplant models were used to test the in vivo effect of PNA CCR5 by targeting CCR5 in acute allograft rejection. PNA CCR5-treated recipients demonstrated significant prolongation (12.0 +/- 1.75 days) of functional allograft survival compared with saline (6.5 +/- 0.58 days)- or PNA mismatch-treated recipients (6.5 +/- 0.50 days). The PNA CCR5 blocked the expression of CCR5 in spleen CD3+ T cells. Lymphocytes from PNA CCR5-treated mice exhibited a reduced degree of proliferation comparable to that of saline- and PNA mismatch-treated mice. The present study indicated that PNA CCR5 has a substantial therapeutic effect to inhibit acute allograft rejection.

Regulation of anterograde transport of alpha2-adrenergic receptors by the N termini at multiple intracellular compartments

The studies on the intrinsic structural determinants for export trafficking of G protein-coupled receptors (GPCRs) have been mainly focused on the C termini of the receptors. In this report we determined the role of the extracellular N termini of alpha(2)-adrenergic receptors (alpha(2)-ARs) in the anterograde transport from the endoplasmic reticulum (ER) through the Golgi to the cell surface. The N-terminal-truncated alpha(2B)-AR mutant is completely unable to target to the cell surface. A single Met-6 residue is essential for the export of alpha(2B)-AR from the ER, likely through modulating correct alpha(2B)-AR folding in the ER. The Tyr-Ser motif, highly conserved in the membrane-proximal N termini of all alpha(2)-AR subtypes, is required for the exit of alpha(2A)-AR and alpha(2B)-AR from the Golgi apparatus, thus representing a novel Tyr-based motif modulating GPCR transport at the Golgi level. These data provide the first evidence indicating an essential role of the N termini of GPCRs in the export from distinct intracellular compartments along the secretory pathway.

Severe vitamin D deficiency in chronic renal failure patients on peritoneal dialysis

The aim of this study was to evaluate the prevalence of vitamin D deficiency in chronic renal failure (CRF) patients on peritoneal dialysis (PD) and to correlate the findings with various demographic and renal osteodystrophy markers.

METHOD

This cross-sectional, multicenter study was carried out in 273 PD patients with a mean age of 61.7 +/- 10.9 years and mean duration of PD 3.3 +/- 2.2 years. It included 123 female and 150 male patients from 20 centers in Greece and Turkey, countries that are on the same latitude, namely, 36-42 degrees north. We measured 25(OH)D3 and 1.25(OH)2D3 levels and some other clinical and laboratory indices of bone mineral metabolism.

RESULTS

Of these 273 patients 92% (251 patients) had vitamin D deficiency i.e. serum 25(OH)D3 levels less than 15 ng/ml, 119 (43.6%) had severe vitamin D deficiency i.e., serum 25(OH)D3 levels, less than 5 ng/ml, 132 (48.4%) had moderate vitamin D deficiency i.e., serum 25(OH)D3 levels, 5-15 ng/ml, 12 (4.4%) vitamin D insufficiency i.e., serum 25(OH)D3 levels 15 - 30 ng/ml and only 10 (3.6%) had adequate vitamin D stores. We found no correlation between 25(OH)D3 levels and PTH, serum albumin, bone alkaline phosphatase, P, and Ca x P. In multiple regression analyses, the independent predictors of 25(OH)D3 were age, presence of diabetes (DM-CRF), levels of serum calcium and serum 1.25(OH)2D3.

CONCLUSION

We found a high prevalence (92%) of vitamin D deficiency in these 273 PD patients, nearly one half of whom had severe vitamin D deficiency. Vitamin D deficiency is more common in DM-CRF patients than in non-DM-CRF patients. Our findings suggest that these patients should be considered for vitamin D supplementation.

Nano-structural bioactive gradient coating fabricated by computer controlled plasma-spraying technology

The poor mechanical property of hydroxyapatite was the major problem for load bearing and implant coating in clinical applications. To overcome this weakness, a bioactive gradient coating with a special design composition of hydroxyapatite (HA), ZrO2, Ti, bioglass was developed. This 120 microm coating with an upper layer of 30-50 microm porous HA produced by computer controlled plasma spraying which maintained energy level of the plasma which ensure proper melting of powder. The crystal size of the coating was 18.6-26.2 nm. Transformation of t-ZrO2 to m-ZrO2 reduced the thermal stress that weakened the coating and lowered down interfacial strength of the coating and metal substrate. Thermal stress of sprayed coating was 16.4 MPa which was much smaller than the sample without thermal treatment of 67.1 MPa. Interfacial strength between the coating and metal substrate was 53 MPa which is much higher than conventional Hydroxyapatite coating. Based on XRD analysis crystallinity of HA approached 98%. Therefore, high temperature treatment improved long term stability of the coating through improved crystallinity of hydroxyapatite and reduced other impure calcium phosphate phase.

Regulation of G protein-coupled receptor export trafficking

G protein-coupled receptors (GPCRs) constitute a superfamily of cell-surface receptors which share a common topology of seven transmembrane domains and modulate a variety of cell functions through coupling to heterotrimeric G proteins by responding to a vast array of stimuli. The magnitude of cellular response elicited by a given signal is dictated by the level of GPCR expression at the plasma membrane, which is the balance of elaborately regulated endocytic and exocytic trafficking. This review will cover recent advances in understanding the molecular mechanism underlying anterograde transport of the newly synthesized GPCRs from the endoplasmic reticulum (ER) through the Golgi to the plasma membrane. We will focus on recently identified motifs involved in GPCR exit from the ER and the Golgi, GPCR folding in the ER and the rescue of misfolded receptors from within, GPCR-interacting proteins that modulate receptor cell-surface targeting, pathways that mediate GPCR traffic, and the functional role of export in controlling GPCR signaling.

Vacuolar-type H+-ATPases at the plasma membrane regulate pH and cell migration in microvascular endothelial cells

Microvascular endothelial cells involved in angiogenesis are exposed to an acidic environment that is not conducive for growth and survival. These cells must exhibit a dynamic intracellular (cytosolic) pH (pHcyt) regulatory mechanism to cope with acidosis, in addition to the ubiquitous Na+/H+exchanger and HCO3−-based H+-transporting systems. We hypothesize that the presence of plasmalemmal vacuolar-type proton ATPases (pmV-ATPases) allows microvascular endothelial cells to better cope with this acidic environment and that pmV-ATPases are required for cell migration. This study indicates that microvascular endothelial cells, which are more migratory than macrovascular endothelial cells, express pmV-ATPases. Spectral imaging microscopy indicates a more alkaline pHcytat the leading than at the lagging edge of microvascular endothelial cells. Treatment of microvascular endothelial cells with V-ATPase inhibitors decreases the proton fluxes via pmV-ATPases and cell migration. These data suggest that pmV-ATPases are essential for pHcytregulation and cell migration in microvascular endothelial cells.

BOARD-INVITED REVIEW: Intrauterine growth retardation: Implications for the animal sciences1

Intrauterine growth retardation (IUGR), defined as impaired growth and development of the mammalian embryo/fetus or its organs during pregnancy, is a major concern in domestic animal production. Fetal growth restriction reduces neonatal survival, has a permanent stunting effect on postnatal growth and the efficiency of feed/forage utilization in offspring, negatively affects whole body composition and meat quality, and impairs long-term health and athletic performance. Knowledge of the underlying mechanisms has important implications for the prevention of IUGR and is crucial for enhancing the efficiency of livestock production and animal health. Fetal growth within the uterus is a complex biological event influenced by genetic, epigenetic, and environmental factors, as well as maternal maturity. These factors impact on the size and functional capacity of the placenta, uteroplacental blood flows, transfer of nutrients and oxygen from mother to fetus, conceptus nutrient availability, the endocrine milieu, and metabolic pathways. Alterations in fetal nutrition and endocrine status may result in developmental adaptations that permanently change the structure, physiology, metabolism, and postnatal growth of the offspring. Impaired placental syntheses of nitric oxide (a major vasodilator and angiogenic factor) and polyamines (key regulators of DNA and protein synthesis) may provide a unified explanation for the etiology of IUGR in response to maternal undernutrition and overnutrition. There is growing evidence that maternal nutritional status can alter the epigenetic state (stable alterations of gene expression through DNA methylation and histone modifications) of the fetal genome. This may provide a molecular mechanism for the role of maternal nutrition on fetal programming and genomic imprinting. Innovative interdisciplinary research in the areas of nutrition, reproductive physiology, and vascular biology will play an important role in designing the next generation of nutrient-balanced gestation diets and developing new tools for livestock management that will enhance the efficiency of animal production and improve animal well being.

The uptake of glutamine and release of arginine, citrulline and proline by the small intestine of developing pigs

Arteriovenous (A-V) differences in the plasma concentrations of amino acids across the jejunum were studied in preweaning (14- to 21-d-old) and post-weaning (29- to 58-d-old) pigs in the postabsorptive state. Glutamine was the only amino acid that was extracted by the small intestine in both pre- and post-weaning pigs. The production of citrulline by the jejunum was low in preweaning pigs, but was threefold greater in the post-weaning pigs than in the preweaning pigs. The output of proline by the intestine was observed in the post-weaning pigs but not in the preweaning pigs. Arginine and alanine were the predominant amino acids released by the jejunum of the pre- and post-weaning pigs, respectively. Whereas glutamate was the major amino acid formed from glutamine in pig enterocytes in vitro, the jejunum of the post-weaning pigs released comparable amounts of citrulline, proline and glutamate in vivo. There were no significant A-V differences in the concentrations of urea, ornithine, taurine, tyrosine, serine, glycine and nutritionally essential amino acids in either the preweaning or the post-weaning pigs. Thus, we demonstrated for the first time the uptake in vivo of glutamine and the release of arginine, alanine, citrulline, glutamate and proline by the small intestine of developing pigs. Our findings on the release in vivo of citrulline (the precursor of arginine) and proline by the small intestine of the pre- and post-weaning pigs provide a basis for explaining why arginine and proline are nutritionally essential amino acids for young suckling piglets but not for adult pigs.