Sphingolipids (SLs) play essential roles in most eukaryotes, but in the trypanosomatid protozoan Leishmania major their functions differ significantly. Previously we showed that null mutants defective in de novo sphingoid base synthesis (spt2−) lacked SLs but grew well and retained lipid rafts while replicating as promastigotes in vitro. However, they experienced catastrophic defects in membrane trafficking on entry into stationary phase, and failed to differentiate to the infective metacyclic form. Here we showed this mutant retained the ability to enter macrophages silently and inhibit activation, although as expected most parasites were destroyed. However, in mouse infections, after a delay rapidly progressive lesions appeared, and purified amastigotes were fully virulent to macrophages and mice. Mass spectrometry of spt2− amastigote lipids revealed the presence of high levels of parasite-specific inositol phosphorylceramides (IPCs) not synthesized by the mammalian hosts. Inhibitor studies showed that salvage occurs at the level of complex SLs, suggesting that parasites carry out ‘headgroup’ remodelling. Additionally, we describe a new defect of the spt2− promastigotes involving ‘empty’ acidocalcisomes (ACs), which may point to the origin of this organelle from the lysosome-related organelle/multivesicular body biogenesis pathway. However, ACs in spt2− amastigotes appeared quantitatively and morphologically normal. Thus salvage of SLs and other molecules by intracellular amastigotes play key roles in AC biogenesis and parasite survival in the host.
Diabetes is the leading cause of chronic kidney disease, and the prevalence of both diseases is rising worldwide. Treatment of type 2 diabetes is difficult in patients with chronic kidney disease because most oral antidiabetic agents are affected by renal function and their use may be contraindicated in this patient population. Antidiabetic agents that can be used in patients with type 2 diabetes and declining renal function are needed. Incretin-based therapies, such as dipeptidyl peptidase-4 inhibitors, are a recent therapeutic class of glucose-lowering agents that may offer an effective treatment option in patients with chronic kidney disease. Within the dipeptidyl peptidase-4 class, linagliptin has a unique profile with a primarily nonrenal route of elimination, requiring no dose adjustment in patients with chronic kidney disease. This communication summarizes the findings of a 1-year, randomized, double-blind, placebo-controlled study demonstrating the favorable safety and efficacy profile of linagliptin in patients with type 2 diabetes and severe renal impairment.
renal impairment; incretin; DPP-4 inhibitor; type 2 diabetes
Diffuse large B-cell lymphoma (DLBCL) is curable in 60% of patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). MYC translocations, with or without BCL2 translocations, have been associated with inferior survival in DLBCL. We investigated whether expression of MYC protein, with or without BCL2 protein expression, could risk-stratify patients at diagnosis.
Patients and Methods
We determined the correlation between presence of MYC and BCL2 proteins by immunohistochemistry (IHC) with survival in two independent cohorts of patients with DLBCL treated with R-CHOP. We further determined if MYC protein expression correlated with high MYC mRNA and/or presence of MYC translocation.
In the training cohort (n = 167), MYC and BCL2 proteins were detected in 29% and 44% of patients, respectively. Concurrent expression (MYC positive/BCL2 positive) was present in 21% of patients. MYC protein correlated with presence of high MYC mRNA and MYC translocation (both P < .001), but the latter was less frequent (both 11%). MYC protein expression was only associated with inferior overall and progression-free survival when BCL2 protein was coexpressed (P < .001). Importantly, the poor prognostic effect of MYC positive/BCL2 positive was validated in an independent cohort of 140 patients with DLBCL and remained significant (P < .05) after adjusting for presence of high-risk features in a multivariable model that included elevated international prognostic index score, activated B-cell molecular subtype, and presence of concurrent MYC and BCL2 translocations.
Assessment of MYC and BCL2 expression by IHC represents a robust, rapid, and inexpensive approach to risk-stratify patients with DLBCL at diagnosis.
To describe the long-term (≥ 10 years) benefits of clinical human papillomavirus (HPV) DNA testing for cervical precancer and cancer risk prediction.
Cervicovaginal lavages collected from 19,512 women attending a health maintenance program were retrospectively tested for HPV using a clinical test. HPV positives were tested for HPV16 and HPV18 individually using a research test. A Papanicolaou (Pap) result classified as atypical squamous cells of undetermined significance (ASC-US) or more severe was considered abnormal. Women underwent follow-up prospectively with routine annual Pap testing up to 18 years. Cumulative incidence rates (CIRs) of ≥ grade 3 cervical intraepithelial neoplasia (CIN3+) or cancer for enrollment test results were calculated.
A baseline negative HPV test provided greater reassurance against CIN3+ over the 18-year follow-up than a normal Pap (CIR, 0.90% v 1.27%). Although both baseline Pap and HPV tests predicted who would develop CIN3+ within the first 2 years of follow-up, only HPV testing predicted who would develop CIN3+ 10 to 18 years later (P = .004). HPV16- and HPV18-positive women with normal Pap were at elevated risk of CIN3+ compared with other HPV-positive women with normal Pap and were at similar risk of CIN3+ compared with women with a low-grade squamous intraepithelial Pap.
HPV testing to rule out cervical disease followed by Pap testing and possibly combined with the detection of HPV16 and HPV18 among HPV positives to identify those at immediate risk of CIN3+ would be an efficient algorithm for cervical cancer screening, especially in women age 30 years or older.
Objective. To assess the prevalence and characteristics of curriculum in dual doctor of pharmacy (PharmD)/master of public health (MPH) degree programs offered by US pharmacy programs.
Methods. An 18-item survey instrument was developed and distributed online to faculty members at US colleges and schools of pharmacy.
Results. Of the 110 colleges and schools that responded, 23 (21%) offered a PharmD/MPH degree. Common characteristics of these 23 programs included current PharmD program structure (3 + 1 year), early curricular recruitment, small enrollment, and interdisciplinary coursework occurring online and in the classroom. The impact of the dual degree on the curriculum and longevity of the dual-degree programs varied. About 55% of responding programs without a formal dual-degree program reported that additional public health training was available.
Conclusion. Twenty-one percent of colleges and schools of pharmacy offer a combined PharmD/MPH dual degree. Most programs required an additional 1 or 2 semesters to complete both degrees.
pharmacy education; public health; masters of public health; dual degree
Despite advances in the understanding of diffuse large B-cell lymphoma (DLBCL) biology, only the clinically based International Prognostic Index (IPI) is used routinely for risk stratification at diagnosis. To find novel prognostic markers, we analyzed flow cytometric data from 229 diagnostic DLBCL samples using an automated multiparameter data analysis approach developed in our laboratory. By using the developed automated data analysis pipeline, we identified 71 of 229 cases as having more than 35% B cells with a high side scatter (SSC) profile, a parameter reflecting internal cellular complexity. This high SSC B-cell feature was associated with inferior overall and progression-free survival (P = .001 and P = .01, respectively) and remained a significant predictor of overall survival in multivariate Cox regression analysis (IPI, P = .001; high SSC, P = .004; rituximab, P = .53).
This study suggests that high SSC among B cells may serve as a useful biomarker to identify patients with DLBCL at high risk for relapse. This is of particular interest because this biomarker is readily available in most clinical laboratories without significant alteration to existing routine diagnostic strategies or incurring additional costs.
Side scatter; Flow cytometry; Diffuse large B-cell lymphoma; Lymphoma; Survival
Rheumatoid arthritis (RA) remains a major clinical problem with many patients having continuing systemic inflammatory disease resulting in progressive erosive damage and high levels of disability. A range of pro-inflammatory cytokines including tumor necrosis factor (TNF), interleukin (IL)-1 and IL-6 are involved in RA pathogenesis; these cytokines can be specifically inhibited by biological agents. Tocilizumab (TCZ) is a recombinant humanized anti-IL-6 receptor monoclonal antibody, administered monthly by intravenous infusion that prevents IL-6 signal transduction. There is strong evidence that it is both clinically efficacious and cost-effective. There have been several key clinical trials evaluating the safety and efficacy of TCZ in RA patients. We review five Phase II trials and seven Phase III trials enrolling a total of 626 and 5268 RA patients respectively. The American College of Rheumatology (ACR) response criteria were used as the primary or secondary outcome measure in all trials. Overall these trials demonstrated that TCZ was effective in the treatment of RA in a number of patient groups, including those with an inadequate response to methotrexate (MTX) or TNF inhibition. TCZ use, both as monotherapy and in combination with MTX, improved the signs and symptoms of RA within several weeks of commencing treatment. Additionally, TCZ was shown to reduce radiological disease progression and improve physical function, both as monotherapy and in combination with MTX. A 5-year extension study demonstrated that TCZ sustained good long-term efficacy and safety profiles. TCZ was generally well tolerated. Although its use increased the risk of an adverse event, these were usually mild to moderate in severity and treatment did not increase the risk of a serious adverse event in comparison to controls. Due to moderate increases in serum levels of total cholesterol, triglycerides, high-density lipoproteins and serum transaminases seen in those patients treated with TCZ, as well as severe neutropenia in some, regular blood monitoring of full blood count, liver function and lipids is recommended. Given its clinical efficacy in the treatment of RA, TCZ may be beneficial in the treatment of other autoimmune diseases where IL-6 plays a role in the inflammatory cascade.
tocilizumab; rheumatoid arthritis; review; IL-6
Signal Regulatory Protein γ (SIRPγ) is a member of a closely related family of three cell surface receptors implicated in modulating immune/inflammatory responses. SIRPγ is expressed on T lymphocytes where it appears to be involved in the integrin-independent adhesion of lymphocytes to antigen-presenting cells. Here we describe the first full length structure of the extracellular region of human SIRPγ.
We obtained crystals of SIRPγ by making a complex of the protein with the Fab fragment of the anti-SIRP antibody, OX117, which also binds to SIRPα and SIRPβ. We show that the epitope for FabOX117 is formed at the interface of the first and second domains of SIRPγ and comprises residues which are conserved between all three SIRPs. The FabOX117 binding site is distinct from the region in domain 1 which interacts with CD47, the physiological ligand for both SIRPγ and SIRPα but not SIRPβ. Comparison of the three domain structures of SIRPγ and SIRPα showed that these receptors can adopt different overall conformations due to the flexibility of the linker between the first two domains. SIRPγ in complex with FabOX117 forms a dimer in the crystal. Binding to the Fab fixes the position of domain 1 relative to domains 2/3 exposing a surface which favours formation of a homotypic dimer. However, the interaction appears to be relatively weak since only monomers of SIRPγ were observed in sedimentation velocity analytical ultracentrifugation of the protein alone. Studies of complex formation by equilibrium ultracentrifugation showed that only a 1:1 complex of SIRPγ: FabOX117 was formed with a dissociation constant in the low micromolar range (Kd = 1.2 +/− 0.3 μM).
The three-domain extracellular regions of SIRPs are structurally conserved but show conformational flexibility in the disposition of the amino terminal ligand-binding Ig domain relative to the two membrane proximal Ig domains. Binding of a cross-reactive anti-SIRP Fab fragment to SIRPγ stabilises a conformation that favours SIRP dimer formation in the crystal structure, though this interaction does not appear sufficiently stable to be observed in solution.
Antigen-binding complex; Signal regulatory protein; Receptor structure
Slow axonal transport conveys perikaryally-synthesized cytosolic proteins in a rate-class called Slow Component-b (SCb). One such protein – α-synuclein – is largely conveyed in SCb, and is also a key player in a group of neurodegenerative diseases called synucleinopathies. Axonal transport defects of α-synuclein have been hypothesized to play a role in synucleinopathies, but mechanisms moving α-synuclein in slow axonal transport are unclear. Here we use a recently developed model-system in our laboratory to visualize the slow transport of α-synuclein, comparing it to another SCb protein synapsin. Despite differences inbiological properties and overallsolubility in axons, the anterograde transport of both SCb proteins was strikingly similar, suggesting commonalities in slow axonal transport mechanisms of seemingly diverse cytosolic cargoes. The data support a model where SCb proteins dynamically organize into ‘transport-competent’ complexes that are conveyed via transient associations with other persistently-moving cargoes (“mobile-units”). The identity of the latter is yet unknown. Visualizing normal α-synuclein transport may also open the door to studies of α-synuclein transport in pathologic states.
Cytosolic synaptic proteins; synapsin; α-synuclein; slow axonal transport; transport packets; cargo complexes; diffusion; slow component – b; SCb
The TCA cycle is the central hub of oxidative metabolism, running in the classic forward direction to provide carbon for biosynthesis and reducing agents for generation of ATP. Our metabolic tracer studies in melanoma cells showed that in hypoxic conditions the TCA cycle is largely disconnected from glycolysis. By studying the TCA branch point metabolites, acetyl CoA and citrate, as well as the metabolic endpoints glutamine and fatty acids, we developed a comprehensive picture of the rewiring of the TCA cycle that occurs in hypoxia. Hypoxic tumor cells maintain proliferation by running the TCA cycle in reverse. The source of carbon for acetyl CoA, citrate, and fatty acids switches from glucose in normoxia to glutamine in hypoxia. This hypoxic flux from glutamine into fatty acids is mediated by reductive carboxylation. This reductive carboxylation is catalyzed by two isocitrate dehydrogenases, IDH1 and IDH2. Their combined action is necessary and sufficient to effect the reverse TCA flux and maintain cellular viability.
Objectives. Granulomatosis with polyangiitis (Wegener's) (GPA) and microscopic polyangiitis (MPA) are uncommon and have unknown aetiology. The aim of the study was to investigate the epidemiology of GPA and MPA in a stable, well-defined population looking for differences in the pattern of occurrence, which might suggest a different aetiology.
Methods. Since 1988, we have maintained a prospective register of all patients with systemic vasculitis attending the Norfolk and Norwich University Hospital. Patients presenting with new-onset GPA and MPA as defined by the European Medicines Agency algorithm and registered with general practitioners in the former Norwich Health Authority area between 1988 and 2010 were identified. The population in 2008 was estimated to be 459 000 (221 000 males).
Results. One hundred and eleven GPA and 58 MPA incident cases were identified during 1988–2010. The overall annual incidence of GPA and MPA was 11.3/million and 5.9/million, respectively. There was evidence of a cyclical pattern of occurrence with a periodicity of 7.6 years for GPA with a peak incidence of 28.3/million in 2005 and the lowest in 2002 (2.2/million). Other lesser peaks occurred in 1990 and 1996. While the peak incidence of MPA was in 2008 (15.2/million), there was no convincing evidence of periodicity. The incidence of cANCA/PR3- or pANCA/MPO-positive vasculitis showed a similar pattern to GPA and MPA, respectively.
Conclusion. This study lends support to the notion that the aetiology of GPA and MPA may be distinct conditions with different aetiologies. The cyclical incidence of GPA is possibly an indication for the influence of infection.
granulomatosis with polyangiitis (Wegener's); Wegener's granulomatosis; microscopic polyangiitis; epidemiology; vasculitis
HLA class II-restricted regulatory T cell (Treg) epitopes in IgG (also called “Tregitopes”) have been reported to suppress immune responses to coadministered antigens by stimulating the expansion of natural Tregs (nTregs). Here we evaluate their impact on human immune responses to islet cell antigens ex vivo and on the modulation of type 1 diabetes (T1D) in a murine model in vivo. Co-administration of Tregitopes and T1D antigens delayed development of hyperglycemia and reduced the incidence of diabetes in NOD mice. Suppression of diabetes could be observed even following onset of disease. To measure the impact of Tregitope treatment on T cell responses, we evaluated the effect of Tregitope treatment in DO11.10 mice. Upregulation of FoxP3 in KJ1-26-stained OVA-specific CD4+ T cells was observed following treatment of DO11.10 mice with Tregitopes, along with reductions in anti-OVA Ig and T effector responses. In ex vivo studies of human T cells, peripheral blood mononuclear cells' (PBMC) responses to GAD65 epitopes in the presence and absence of Tregitope were variable. Suppression of immune responses to GAD65 epitopes ex vivo by Tregitope appeared to be more effective in assays using PBMC from a newly diagnosed diabetic subject than for other more established diabetic subjects, and correlation of the degree of suppression with predicted HLA restriction of the Tregitopes was confirmed. Implementation of these defined regulatory T cell epitopes for therapy of T1D and other autoimmune diseases may lead to a paradigm shift in disease management.
Helicobacter pylori survives and grows at low pHs via acid acclimation mechanisms that enable periplasmic pH homeostasis. Important components include a cytoplasmic urease; a pH-gated urea channel, UreI; and periplasmic α-carbonic anhydrase. To allow the rapid adjustment of periplasmic pH, acid acclimation components are recruited to the inner membrane in acid. The ArsRS two-component system, in an acid-responsive manner, controls the transcription of the urease gene cluster and α-carbonic anhydrase. The aim of this study is to determine the role of ArsS in protein trafficking as a component of acid acclimation. H. pylori wild-type and ΔarsS bacteria were incubated at acidic and neutral pHs. Intact bacteria, purified membranes, and total protein were analyzed by Western blotting and urease activity measurements. The total urease activity level was decreased in the ΔarsS strain, but the acid activation of UreI was unaffected. A 30-min acid exposure increased the level and activity of urease proteins at the membrane in the wild type but not in the ΔarsS strain. The urease levels and activity of the ΔarsS strain after a 90-min acid exposure were similar to those of the wild type. ArsS, in addition to its role in urease gene transcription, is also involved in the recruitment of urease proteins to the inner membrane to augment acid acclimation during acute acid exposure. Urease membrane recruitment following prolonged acid exposure in the absence of ArsS was similar to that of the wild type, suggesting a compensatory mechanism, possibly regulated by FlgS, underscoring the importance of urease membrane recruitment and activation in periplasmic pH homeostasis.
We report the case of a 64-year-old patient in whom a pulmonary artery catheter formed a knot fixed within the right ventricle in the region of the tricuspid valve apparatus. Knot formation is a recognized complication associated with pulmonary artery catheters (PAC) insertion. This problem is usually dealt with by simply withdrawing the PAC until the knot impacts onto the introducer and after enlarging the puncture site by a small skin incision removing the introducer-PAC as one unit. However, we recently encountered a situation where the PAC was knotted around the tricuspid valve apparatus and could not be withdrawn. An interventional radiologist was able to unknot the catheter and release it from the tricuspid valve. We reviewed the literature related to this topic. We believe our experience could be of use to others.
Invasive hemodynamic monitoring; pulmonary artery catheter; pulmonary artery catheter complications; tricuspid valve
Complementary and alternative medicine includes a number of exercise modalities, such as tai chi, qigong, yoga, and a variety of lesser-known movement therapies. A meta-analysis of the current literature was conducted estimating the effect size of the different modalities, study quality and bias, and adverse events. The level of research has been moderately weak to date, but most studies report a medium-to-high effect size in pain reduction. Given the lack of adverse events, there is little risk in recommending these modalities as a critical component in a multimodal treatment plan, which is often required for fibromyalgia management.
fibromyalgia; exercise; complementary and alternative; efficacy; safety
The downstream targets of amyloid β (Aβ)-oligomers remain elusive. One hypothesis is that Aβ-oligomers interrupt axonal transport. Although previous studies have demonstrated Aβ-induced transport blockade, early effects of low-n soluble Aβ-oligomers on axonal transport remain unclear. Furthermore, the cargo selectivity for such deficits (if any) or the specific effects of Aβ on the motility kinetics of transported cargoes are also unknown. Toward this, we visualized axonal transport of vesicles in cultured hippocampal neurons treated with picomolar (pm) levels of cell-derived soluble Aβ-oligomers. We examined select cargoes thought to move as distinct organelles and established imaging parameters that allow organelle tracking with consistency and high fidelity – analyzing all data in a blinded fashion. Aβ-oligomers induced early and selective diminutions in velocities of synaptic cargoes but had no effect on mitochondrial motility, contrary to previous reports. These changes were N-methyl d-aspartate receptor/glycogen synthase kinase-3β dependent and reversible upon washout of the oligomers. Cluster-mode analyses reveal selective attenuations in faster-moving synaptic vesicles, suggesting possible decreases in cargo/motor associations, and biochemical experiments implicate tau phosphorylation in the process. Collectively, the data provide a biological basis for Aβ-induced axonal transport deficits.
amyloid β-oligomers; axonal transport; cargo-motor regulation; molecular motors; synaptic loss; transport packets
Osteoarthritis (OA) is the most common type of arthritis, causing significant joint pain and disability. It is already a major cause of healthcare expenditure and its incidence will further increase with the ageing population. Current treatments for OA have major limitations and new analgesic treatments are needed. Synovitis is prevalent in OA and is associated with pain. Hydroxychloroquine is used in routine practice for treating synovitis in inflammatory arthritides, such as rheumatoid arthritis. We propose that treating patients with symptomatic hand OA with hydroxychloroquine will be a practical and safe treatment to reduce synovitis and pain.
HERO is an investigator-initiated, multicentre, randomized, double-blind, placebo-controlled trial. A total of 252 subjects with symptomatic hand OA will be recruited across primary and secondary care sites in the UK and randomized on a 1:1 basis to active treatment or placebo for 12 months. Daily medication dose will range from 200 to 400 mg according to ideal body weight. The primary endpoint is change in average hand pain during the previous two weeks (measured on a numerical rating scale (NRS)) between baseline and six months. Secondary endpoints include other self-reported pain, function and quality-of-life measures and radiographic structural change at 12 months. A health economics analysis will also be performed. An ultrasound substudy will be conducted to examine baseline levels of synovitis. Linear and logistic regression will be used to compare changes between groups using univariable and multivariable modelling analyses. All analyses will be conducted on an intention-to-treat basis.
The HERO trial is designed to examine whether hydroxychloroquine is an effective analgesic treatment for OA and whether it provides any long-term structural benefit. The ultrasound substudy will address whether baseline synovitis is a predictor of therapeutic response. This will potentially provide a new treatment for OA, which could be of particular use in the primary care setting.
Double-blind; Hand osteoarthritis; Hydroxychloroquine; Placebo-controlled; Randomized
T cell-dependent development of anti-factor VIII (FVIII) antibodies that neutralize FVIII activity is a major obstacle to replacement therapy in hemophilia A. To create a less immunogenic therapeutic protein, recombinant FVIII can be modified to reduce HLA binding of epitopes based on predicted anchoring residues. Here, we used immunoinformatics tools to identify C2 domain HLA DR epitopes and predict site-specific mutations that reduce immunogenicity. Epitope peptides corresponding to original and modified sequences were validated in HLA binding assays and in immunizations of hemophilic E16 mice, DR3 and DR4 mice and DR3xE16 mice. Consistent with immunoinformatics predictions, original epitopes are immunogenic. Immunization with selected modified sequences lowered immunogenicity for particular peptides and revealed residual immunogenicity of incompletely de-immunized modified peptides. The stepwise approach to reduce protein immunogenicity by epitope modification illustrated here is being used to design and produce a functional full-length modified FVIII for clinical use.
Epitope; T cell; Factor VIII; Inhibitors; De-immunization
We describe a strategy for analyzing axonal transport of cytosolic proteins (cps) using photoactivatable GFp—paGFp—with modifications of standard imaging components that can be retroactively fitted to a conventional epifluorescence microscope. the photoactivation and visualization are nearly simultaneous, allowing studies of proteins with rapidly mobile fractions. cultured hippocampal neurons are transfected with paGFp-tagged constructs, a discrete protein population within axons is photoactivated, and then the activated population is tracked by live imaging. We show the utility of this method in analyzing axonal transport of cps that have inherent diffusible pools and distinguish this transport modality from passive diffusion and vesicle transport. the analytical tools used to quantify the motion are also described. aside from the time needed for preparation of neuronal cultures/transfection, the experiment takes 2–3 h, during which time several axons can be imaged and analyzed. these methods should be easy to adopt by most laboratories and may also be useful for monitoring cp movement in other cell types.
Monogenic hereditary diseases, such as haemophilia A and B, are ideal targets for gene therapeutic approaches. While these diseases can be treated with protein therapeutics, such as factor VIII (F8) or IX (F9), the notion that permanent transfer of the genes encoding these factors can cure haemophilia is very attractive. An underlying problem with a gene therapy approach, however, is the patient’s immune response to the therapeutic protein (as well as to the transmission vector), leading to the formation of inhibitory antibodies. Even more daunting is reversing an existing immune response in patients with pre-existing inhibitors. In this review, we will describe the laboratory and clinical progress, and the challenges met thus far, in achieving the goal of gene therapy efficacy, with a focus on the goal of tolerance induction.
Haemophilia; factor VIII (F8); factor IX (F9); gene therapy; vectors; inhibitors; Immune tolerance
In this paper we report the molecular profiling, lipidome and proteome, of the plant organelle known as an oil body (OB). The OB is remarkable in that it is able to perform its biological role (storage of triglycerides) whilst resisting the physical stresses caused by changes during desiccation (dehydration) and germination (rehydration). The molecular profile that confers such extraordinary physical stability on OBs was determined using a combination of 31P/1H nuclear magnetic resonance (NMR), high-resolution mass spectrometry and nominal mass-tandem mass spectrometry for the lipidome, and gel-electrophoresis-chromatography-tandem mass spectrometry for the proteome. The integrity of the procedure for isolating OBs was supported by physical evidence from small-angle neutron-scattering experiments. Suppression of lipase activity was crucial in determining the lipidome. There is conclusive evidence that the latter is dominated by phosphatidylcholine (∼60 %) and phosphatidylinositol (∼20 %), with a variety of other head groups (∼20 %). The fatty acid profile of the surface monolayer comprised palmitic, linoleic and oleic acids (2:1:0.25, 1H NMR) with only traces of other fatty acids (C24:0, C22:0, C18:0, C18:3, C16:2; by MS). The proteome is rich in oleosins (78 %) with the remainder being made up of caleosins and steroleosins. These data are sufficiently detailed to inform an update of the understood model of this organelle and can be used to inform the use of such components in a range of molecular biological, biotechnological and food industry applications. The techniques used in this study for profiling the lipidome throw a new light on the lipid profile of plant cellular compartments.
Electronic supplementary material
The online version of this article (doi:10.1007/s12154-012-0090-1) contains supplementary material, which is available to authorized users.
Lipidome; Proteome; Lipase inhibition; NMR; MS; SANS
Although the presynaptic protein α-synuclein is a recognized player in neurodegeneration, its precise physiologic function(s) and/or role in human disease remains unclear. An emerging consensus from previous studies in lower-order systems is that α-synuclein interferes with vesicle-trafficking pathways; however putative neuronal correlates are unknown. Here we explore consequences of α-synuclein modulation in cultured mouse hippocampal neurons; coupling α-synuclein over-expression and knockout model-systems with contemporary imaging paradigms. Our studies reveal an unexpected role of α-synuclein in attenuating the mobility of recycling pool (RP) vesicles between presynaptic boutons – called “superpool” trafficking – and also in maintaining the overall size of RPs at synapses. While an excess of α-synuclein led to smaller RPs and inhibited inter-synaptic trafficking, an absence of α-synuclein triggered converse changes with larger RPs and enhanced inter-synaptic trafficking. The data collectively suggest a model where α-synuclein maintains RP homeostasis by modulating inter-synaptic vesicular dynamics, and provide a putative neuronal correlate of α-synuclein-induced impairments in vesicle-trafficking previously reported in lower-order systems.
α-synuclein; recycling pool; superpool; synapses; vesicle-trafficking; fluorescence recovery after photobleaching; FM4-64
The primary, stable metabolite of nicotine [(S)-3-(1-methyl-2-pyrrolidinyl) pyridine] in humans is cotinine [(S)-1-methyl-5-(3-pyridinyl)-2-pyrrolidinone]. We have previously shown that cotinine exposure induces convergence and amplification of the GSK3β-dependent PI3 kinase and cholinergic anti-inflammatory systems. The consequence is reduced pro-inflammatory cytokine secretion by human monocytes responding to bacteria or LPS, a TLR4 agonist.
Here we show that cotinine-induced inflammatory suppression may not be restricted to individual Toll-like receptors (TLRs). Indeed, in monocytic cells, cotinine suppresses the cytokine production that is normally resultant upon agonist-specific engagement of all of the major surface exposed TLRs (TLR 2/1; 2/6; 4 and 5), although the degree of suppression varies by TLR.
These results provide further mechanistic insight into the increased susceptibility to multiple bacterial infections known to occur in smokers. They also establish THP-1 cells as a potentially suitable model with which to study the influence of tobacco components and metabolites on TLR-initiated inflammatory events.
Cholinergic anti-inflammatory pathway; Cotinine; Cytokines; GSK3β; Inflammation; THP-1 cells; Tobacco smoking; Toll-like receptors
Missing in metastasis (MIM) is a member of newly emerged inverse BAR-domain protein family and a putative metastasis suppressor. Although reduced MIM expression has been associated with bladder, breast, gastric cancers, evidence for the role of MIM in tumor progression remains scarce and controversial. Herein we characterized a MIM knockout mouse strain and observed that MIM deficient mice often developed enlarged spleens. Autopsy and histological analysis revealed that nearly 78% of MIM(−/−) mice developed tumors with features similar to diffuse large B lymphoma during a period from one to two years. MIM(−/−) mice also exhibited abnormal distribution of B cells in lymphoid organs with decrease in the spleen but increase in the bone marrow and the peripheral blood. Furthermore, the bone marrow of MIM(−/−) mice contained a higher percentage of pre-B2 cells but fewer immature B-cells than wild type mice. In response to CXCL13, a B-cell chemokine released from splenic stromal cells, MIM deficient B-cells did not undergo chemotaxis or morphologic changes in response to the chemokine and also did not internalize CXCR5, the receptor of CXCL13. Microarray analyses demonstrated that MIM is the only member of the I-BAR domain family that was highly expressed in human B cells. However, low or absent MIM expression was common in either primary B-cell malignancies or established B-cell acute lymphocytic leukemia or lymphomas. Thus, our data demonstrate for the first time an important role for MIM in B-cell development and suggests that predisposition of MIM null mice to lymphomagenesis may involve aberrant interactions between B lineage cells and the lymphoid microenvironment.