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61.
Zeidan YH Pettus BJ Elojeimy S Taha T Obeid LM Kawamori T Norris JS Hannun YA 《The Journal of biological chemistry》2006,281(34):24695-24703
Sphingolipids are well established effectors of signal transduction downstream of the tumor necrosis factor (TNF) receptor. In a previous study, we showed that the sphingosine kinase/sphingosine 1-phosphate (S1P) pathway couples TNF receptor to induction of the cyclooxygenase 2 gene and prostaglandin synthesis (Pettus, B. J., Bielawski, J., Porcelli, A. M., Reames, D. L., Johnson, K. R., Morrow, J., Chalfant, C. E., Obeid, L. M., and Hannun, Y. A. (2003) FASEB J. 17, 1411-1421). In this study, the requirement for acid sphingomyelinase and sphingomyelin metabolites in the TNFalpha/prostaglandin E(2) (PGE(2)) pathway was investigated. The amphiphilic compound desipramine, a frequently employed inhibitor of acid sphingomyelinase (ASMase), blocked PGE(2) production. However, the action of desipramine was independent of its action on ASMase, since neither genetic loss of ASMase (Niemann-Pick fibroblasts) nor knockdown of ASMase using RNA interference affected TNFalpha-induced PGE(2) synthesis. Further investigations revealed that desipramine down-regulated acid ceramidase (AC), but not sphingosine kinase, at the protein level. This resulted in a time-dependent drop in sphingosine and S1P levels. Moreover, exogenous administration of either sphingosine or S1P rescued PGE(2) biosynthesis after desipramine treatment. Interestingly, knockdown of endogenous AC by RNA interference attenuated cyclooxygenase 2 induction by TNFalpha and subsequent PGE(2) biosynthesis. Taken together, these results define a novel role for AC in the TNFalpha/PGE(2) pathway. In addition, the results of this study warrant careful reconsideration of desipramine as a specific inhibitor for ASMase. 相似文献
62.
Lau JY Oliver BG Baraket M Beckett EL Hansbro NG Moir LM Wilton SD Williams C Foster PS Hansbro PM Black JL Burgess JK 《PloS one》2010,5(10):e13360
Background
The extracellular matrix is a dynamic and complex network of macromolecules responsible for maintaining and influencing cellular functions of the airway. The role of fibronectin, an extracellular matrix protein, is well documented in asthma. However, the expression and function of fibulin-1, a secreted glycoprotein which interacts with fibronectin, has not been reported. Fibulin-1 is widely expressed in basement membranes in many organs including the lung. There are four isoforms in humans (A–D) of which fibulin-1C and 1D predominate. The objective of this study was to study the expression of fibulin-1 in volunteers with and without asthma, and to examine its function in vitro.Methodology/Principal Findings
We used immunohistochemistry and dot-blots to examine fibulin-1 levels in bronchial biopsies, bronchoalveolar lavage fluid and serum. Real-time PCR for fibulin-1C and 1D, and ELISA and western blotting for fibulin-1 were used to study the levels in airway smooth muscle cells. The function of fibulin-1C was determined by assessing its role, using an antisense oligonucleotide, in cell proliferation, migration and wound healing. A murine model of airway hyperresponsiveness (AHR) was used to explore the biological significance of fibulin-1. Levels of fibulin-1 were significantly increased in the serum and bronchoalveolar lavage fluid of 21 asthmatics compared with 11 healthy volunteers. In addition fibulin-1 was increased in asthma derived airway smooth muscle cells and fibulin-1C contributed to the enhanced proliferation and wound repair in these cells. These features were reversed when fibulin-1C was suppressed using an antisense oligomer. In a mouse model of AHR, treatment with an AO inhibited the development of AHR to methacholine.Conclusions
Our data collectively suggest fibulin-1C may be worthy of further investigation as a target for airway remodeling in asthma. 相似文献63.
64.
Chee J Angstetra E Mariana L Graham KL Carrington EM Bluethmann H Santamaria P Allison J Kay TW Krishnamurthy B Thomas HE 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(4):1702-1712
TNF has been implicated in the pathogenesis of type 1 diabetes. When administered early in life, TNF accelerates and increases diabetes in NOD mice. However, when administered late, TNF decreases diabetes incidence and delays onset. TNFR1-deficient NOD mice were fully protected from diabetes and only showed mild peri-insulitis. To further dissect how TNFR1 deficiency affects type 1 diabetes, these mice were crossed to β cell-specific, highly diabetogenic TCR transgenic I-A(g7)-restricted NOD4.1 mice and Kd-restricted NOD8.3 mice. TNFR1-deficient NOD4.1 and NOD8.3 mice were protected from diabetes and had significantly less insulitis compared with wild type NOD4.1 and NOD8.3 controls. Diabetic NOD4.1 mice rejected TNFR1-deficient islet grafts as efficiently as control islets, confirming that TNFR1 signaling is not directly required for β cell destruction. Flow cytometric analysis showed a significant increase in the number of CD4(+)CD25(+)Foxp3(+) T regulatory cells in TNFR1-deficient mice. TNFR1-deficient T regulatory cells were functionally better at suppressing effector cells than were wild type T regulatory cells both in vitro and in vivo. This study suggests that blocking TNF signaling may be beneficial in increasing the function of T regulatory cells and suppression of type 1 diabetes. 相似文献
65.
Ainsley JA Pettus JM Bosenko D Gerstein CE Zinkevich N Anderson MG Adams CM Welsh MJ Johnson WA 《Current biology : CB》2003,13(17):1557-1563
Coordination of rhythmic locomotion depends upon a precisely balanced interplay between central and peripheral control mechanisms. Although poorly understood, peripheral proprioceptive mechanosensory input is thought to provide information about body position for moment-to-moment modifications of central mechanisms mediating rhythmic motor output. Pickpocket1 (PPK1) is a Drosophila subunit of the epithelial sodium channel (ENaC) family displaying limited expression in multiple dendritic (md) sensory neurons tiling the larval body wall and a small number of bipolar neurons in the upper brain. ppk1 null mutant larvae had normal external touch sensation and md neuron morphology but displayed striking alterations in crawling behavior. Loss of PPK1 function caused an increase in crawling speed and an unusual straight path with decreased stops and turns relative to wild-type. This enhanced locomotion resulted from sustained peristaltic contraction wave cycling at higher frequency with a significant decrease in pause period between contraction cycles. The mutant phenotype was rescued by a wild-type PPK1 transgene and duplicated by expressing a ppk1RNAi transgene or a dominant-negative PPK1 isoform. These results demonstrate that the PPK1 channel plays an essential role in controlling rhythmic locomotion and provide a powerful genetic model system for further analysis of central and peripheral control mechanisms and their role in movement disorders. 相似文献
66.
In this paper we discuss how seasonal temperature variation and life-stage specific developmental thresholds that cause quiescence
can synchronize the seasonal development of exothermic organisms. Using a simple aging model it is shown that minimal seasonal
temperature variation and periods of quiescence during extreme temperature conditions are sufficient to establish stable,
univoltine ovipositional cycles. Quiescence induced by life-stage specific developmental thresholds, in fact, promotes synchronous
oviposition and emergence. The mountain pine beetle, an important insect living in extreme temperature conditions and showing
no evidence of diapause, invites direct application of this model. Simulations using mountain pine beetle parameters are used
to determine temperature regimes for which stable ovipositional cycles exist. 相似文献
67.
Etheresia Pretorius Janette Bester Natasha Vermeulen Boguslaw Lipinski George S. Gericke Douglas B. Kell 《PloS one》2014,9(1)
It is well-known that individuals with increased iron levels are more prone to thrombotic diseases, mainly due to the presence of unliganded iron, and thereby the increased production of hydroxyl radicals. It is also known that erythrocytes (RBCs) may play an important role during thrombotic events. Therefore the purpose of the current study was to assess whether RBCs had an altered morphology in individuals with hereditary hemochromatosis (HH), as well as some who displayed hyperferritinemia (HF). Using scanning electron microscopy, we also assessed means by which the RBC and fibrin morphology might be normalized. An important objective was to test the hypothesis that the altered RBC morphology was due to the presence of excess unliganded iron by removing it through chelation. Very striking differences were observed, in that the erythrocytes from HH and HF individuals were distorted and had a much greater axial ratio compared to that accompanying the discoid appearance seen in the normal samples. The response to thrombin, and the appearance of a platelet-rich plasma smear, were also markedly different. These differences could largely be reversed by the iron chelator desferal and to some degree by the iron chelator clioquinol, or by the free radical trapping agents salicylate or selenite (that may themselves also be iron chelators). These findings are consistent with the view that the aberrant morphology of the HH and HF erythrocytes is caused, at least in part, by unliganded (‘free’) iron, whether derived directly via raised ferritin levels or otherwise, and that lowering it or affecting the consequences of its action may be of therapeutic benefit. The findings also bear on the question of the extent to which accepting blood donations from HH individuals may be desirable or otherwise. 相似文献
68.
Karryn T. Grafton Lyn M. Moir Judith L. Black Nicole G. Hansbro Philip M. Hansbro Janette K. Burgess Brian G. Oliver 《PloS one》2014,9(1)
Background
Tumstatin is a segment of the collagen-IV protein that is markedly reduced in the airways of asthmatics. Tumstatin can play an important role in the development of airway remodelling associated with asthma due to its anti-angiogenic properties. This study assessed the anti-angiogenic properties of smaller peptides derived from tumstatin, which contain the interface tumstatin uses to interact with the αVβ3 integrin.Methods
Primary human lung endothelial cells were exposed to the LF-15, T3 and T7 tumstatin-derived peptides and assessed for cell viability and tube formation in vitro. The impact of the anti-angiogenic properties on airways hyperresponsiveness (AHR) was then examined using a murine model of chronic OVA-induced allergic airways disease.Results
The LF-15 and T7 peptides significantly reduced endothelial cell viability and attenuated tube formation in vitro. Mice exposed to OVA+ LF-15 or OVA+T7 also had reduced total lung vascularity and AHR was attenuated compared to mice exposed to OVA alone. T3 peptides reduced cell viability but had no effect on any other parameters.Conclusion
The LF-15 and T7 peptides may be appropriate candidates for use as novel pharmacotherapies due to their small size and anti-angiogenic properties observed in vitro and in vivo. 相似文献69.
Background
DHA is accumulated in the central nervous system (CNS) before birth and is involved in early developmental processes, such as neurite outgrowth and gene expression.Objective
To determine whether fetal DHA insufficiency occurs and constrains CNS development in term gestation infants.Design
A risk reduction model using a randomized prospective study of term gestation single birth healthy infants born to women (n = 270) given a placebo or 400 mg/day DHA from 16 wk gestation to delivery. Fetal DHA deficiency sufficient to constrain CNS development was assessed based on increased risk that infants in the placebo group would not achieve neurodevelopment scores in the top quartile of all infants in the study.Results
Infants in the placebo group were at increased risk of lower language development assessed as words understood (OR 3.22, CL 1.49–6.94, P = 0.002) and produced (OR 2.61, CL 1.22–5.58, P = 0.01) at 14 mo, and words understood (OR 2.77, CL 1.23–6.28, P = 0.03) and sentences produced (OR 2.60, CL 1.15–5.89, P = 0.02) at 18 mo using the McArthur Communicative Developmental Inventory; receptive (OR 2.23, CL 1.08–4.60, P = 0.02) and expressive language (OR 1.89, CL 0.94–3.83, P = 0.05) at 18 mo using the Bayley Scales of Infant Development III; and visual acuity (OR 2.69, CL 1.10–6.54, P = 0.03) at 2 mo.Trial Registration
ClinicalTrials.gov NCT00620672相似文献70.
Osamah Barasheed Harunor Rashid Mohammad Alfelali Mohamed Tashani Mohammad Azeem Hamid Bokhary Nadeen Kalantan Jamil Samkari Leon Heron Jen Kok Janette Taylor Haitham El Bashir Ziad A.Memish Elizabeth Haworth Edward C.Holmes Dominic E Dwyer Atif Asghar Robert Booy 《Virologica Sinica》2014,(6)
Middle East respiratory syndrome coronavirus(MERS-Co V) has emerged in the Arabian Gulf region, with its epicentre in Saudi Arabia, the host of the ‘Hajj' which is the world's the largest mass gathering. Transmission of MERS-Co V at such an event could lead to its rapid worldwide dissemination. Therefore, we studied the frequency of viruses causing influenza-like illnesses(ILI) among participants in a randomised controlled trial at the Hajj 2013. We recruited 1038 pilgrims from Saudi Arabia, Australia and Qatar during the first day of Hajj and followed them closely for four days. A nasal swab was collected from each pilgrim who developed ILI. Respiratory viruses were detected using multiplex RT-PCR. ILI occurred in 112/1038(11%) pilgrims. Their mean age was 35 years, 49(44%) were male and 35(31%) had received the influenza vaccine pre-Hajj. Forty two(38%) pilgrims had laboratory-confirmed viral infections; 28(25%) rhinovirus, 5(4%) influenza A, 2(2%) adenovirus, 2(2%) human coronavirus OC43/229 E, 2(2%) parainfluenza virus 3, 1(1%) parainfluenza virus 1, and 2(2%) dual infections. No MERS-Co V was detected in any sample. Rhinovirus was the commonest cause of ILI among Hajj pilgrims in 2013. Infection control and appropriate vaccination are necessary to prevent transmission of respiratory viruses at Hajj and other mass gatherings. 相似文献