Significant advances in our understanding of the signalling events during T cell development and differentiation have been made in the past few decades. It is clear that ligation of the T cell receptor (TCR) triggers a series of proximal signalling cascades regulated by an array of protein kinases. These orchestrated and highly regulated series of events, with differential requirements of particular kinases, highlight the disparities between αβ+CD4+ T cells. Throughout this review we summarise both new and old studies, highlighting the role of Tec and MAPK in T cell development and differentiation with particular focus on T helper 2 (TH2) cells. Finally, as the allergy epidemic continues, we feature the role played by TH2 cells in the development of allergy and provide a brief update on promising kinase inhibitors that have been tested in vitro, in pre-clinical disease models in vivo and into clinical studies.
Menopause in women occurs at mid-life. Chimpanzees, in contrast, continue to display cycles of menstrual bleeding and genital swelling, suggestive of ovulation, until near their maximum life span of about 60 years. Because ovulation was not confirmed hormonally, however, the age at which chimpanzees experience menopause has remained uncertain. In the present study, we provide hormonal data from urine samples collected from 30 female chimpanzees, of which 9 were old (>30 years), including 2 above the age of 50 years. Eight old chimpanzees showed clear endocrine evidence of ovulation, as well as cycles of genital swelling that correlated closely with measured endocrine changes. Endocrine evidence thus confirms prior observations (cyclic anogenital swelling) that menopause is a late-life event in the chimpanzee. We also unexpectedly discovered an idiopathic anovulation in some young and middle-aged chimpanzees; this merits further study. Because our results on old chimpanzees validate the use of anogenital swelling as a surrogate index of ovulation, we were able to combine data on swelling and urinary hormones to provide the first estimates of age-specific rates of menopause in chimpanzees. We conclude that menopause occurs near 50 years of age in chimpanzees as it does in women. Our finding identifies a basic difference between the human and chimpanzee aging processes: female chimpanzees can remain reproductively viable for a greater proportion of their life span than women. Thus, while menopause marks the end of the chimpanzee’s life span, women may thrive for decades more.
Menopause; Sexual swelling; Reproduction; Aging; Estrogen; Progesterone
Allostery in bacterial transcription factors arises from changes in global low-frequency protein dynamics. Amino acids that regulate low-frequency dynamics are identified and seen to be evolutionarily conserved.
Allostery is a fundamental process by which ligand binding to a protein alters its activity at a distinct site. There is growing evidence that allosteric cooperativity can be communicated by modulation of protein dynamics without conformational change. The mechanisms, however, for communicating dynamic fluctuations between sites are debated. We provide a foundational theory for how allostery can occur as a function of low-frequency dynamics without a change in structure. We have generated coarse-grained models that describe the protein backbone motions of the CRP/FNR family transcription factors, CAP of Escherichia coli and GlxR of Corynebacterium glutamicum. The latter we demonstrate as a new exemplar for allostery without conformation change. We observe that binding the first molecule of cAMP ligand is correlated with modulation of the global normal modes and negative cooperativity for binding the second cAMP ligand without a change in mean structure. The theory makes key experimental predictions that are tested through an analysis of variant proteins by structural biology and isothermal calorimetry. Quantifying allostery as a free energy landscape revealed a protein “design space” that identified the inter- and intramolecular regulatory parameters that frame CRP/FNR family allostery. Furthermore, through analyzing CAP variants from diverse species, we demonstrate an evolutionary selection pressure to conserve residues crucial for allosteric control. This finding provides a link between the position of CRP/FNR transcription factors within the allosteric free energy landscapes and evolutionary selection pressures. Our study therefore reveals significant features of the mechanistic basis for allostery. Changes in low-frequency dynamics correlate with allosteric effects on ligand binding without the requirement for a defined spatial pathway. In addition to evolving suitable three-dimensional structures, CRP/FNR family transcription factors have been selected to occupy a dynamic space that fine-tunes biological activity and thus establishes the means to engineer allosteric mechanisms driven by low-frequency dynamics.
Allostery is a process by which a molecule binding to one site of a protein alters the activity of the protein at another site. Allostery is typically thought to occur through a change in protein structure, but there is now clear evidence that the dynamic properties of a protein can also regulate allostery without a change in overall conformation. Here we examine two members of a large family of bacterial transcription factors and provide a mechanism to describe the allosteric binding of their activating ligands. We demonstrate, in these systems, that allostery arises as a natural consequence of changes in global low-frequency protein fluctuations on ligand binding. We further demonstrate that the higher dimensional parameter space that describes all potential variant transcription factors can be reduced to a two-dimensional free energy landscape that determines the key molecular parameters that predominantly regulate allostery. We additionally show that the amino acids we determine as contributing sensitively to allosteric control tend to be conserved in diverse bacteria; thus we identify a link between residues that contribute to low-frequency fluctuations and evolutionary selection pressures.
Linear dominance hierarchies organize and maintain stability in female rhesus macaque (Macaca mulatta) social groups regardless of group size. As a consequence of their low social status, subordinate females suffer from an array of adverse outcomes including reproductive compromise, impaired immune function, and poor cardiovascular health. However, data that differentiate limbic-hypothalamic-pituitary adrenal axis (LHPA) parameters between dominant from subordinate female monkeys are inconsistent, bringing into question whether social subordination alters the LHPA axis in female macaques. One difficulty in examining LHPA function in macaques may be the confounding effects of cycling ovarian steroids that are known to modulate LHPA activity. The current study used ovariectomized dominant and subordinate female rhesus monkeys to examine the effect that social subordination has on LHPA function by measuring morning and diurnal serum cortisol levels, dexamethasone (Dex) suppression of cortisol, metabolic clearance of Dex, and ACTH stimulation of adrenal cortisol release and cortisol response following exposure to acute social isolation. Compared to dominant females, subordinate females showed diminished morning peak cortisol secretion, weakened glucocorticoid negative feedback, and decreased adrenal cortisol response to an ACTH challenge as well as a restrained cortisol response following social isolation. However, the metabolism of Dex did not account for differences in Dex suppression between dominant and subordinate females. These results indicate that the ability to mount and limit glucocorticoid release is significantly reduced by psychosocial stress in female rhesus macaques, suggesting a hyporesponsive LHPA phenotype which resembles that observed in several human psychopathologies.
social subordination; dexamethasone; cortisol; ACTH; psychosocial stress; monkeys
Extracellular protein misfolding is implicated in many age-related diseases including Alzheimer's disease, macular degeneration and arthritis. In this study, putative endogenous clients for the chaperone activity of α2-macroglobulin (α2M) were identified after human plasma was subjected to physiologically relevant sheer stress at 37 °C for 10 days. Western blot analysis showed that four major acute phase proteins: ceruloplasmin, fibrinogen, α1-acid glycoprotein and complement component 3, preferentially co-purified with α2M after plasma was stressed. Furthermore, the formation of complexes between α2M and these putative chaperone clients, detected by sandwich ELISA, was shown to be enhanced in response to stress. These results support the hypothesis that α2M plays an important role in extracellular proteostasis by sequestering misfolded proteins and targeting them for disposal, particularly during acute phase reactions.
Electronic supplementary material
The online version of this article (doi:10.1007/s12192-012-0365-z) contains supplementary material, which is available to authorized users.
α2-Macroglobulin; Chaperone; Protein misfolding; Acute phase proteins
Stress-induced eating disorders cause significant health problems and are often comorbid with mood disorders. Emotional feeding, particularly in women, may be important for the development of obesity and failed attempts to lose weight. However, prospective studies assessing the effect of chronic psychosocial stress on appetite in different dietary environments in females are lacking. The present study tested the hypothesis that chronic psychosocial stress would increase consumption of high caloric diet and this emotional feeding would persist even when a healthier diet was available. Socially housed female rhesus monkeys were studied to address whether subordination increases caloric intake when a high fat and sugar diet (HFSD) was available concurrently with a low fat, high fiber diet (LCD). Cortisol responsivity and food intake were quantified during this choice phase and when only the LCD was available. The order of diet condition was counterbalanced to assess whether a history of HFSD would affect appetite. All females preferred the HFSD but subordinates consumed significantly more calories during the choice phase. The increased calorie intake was maintained in subordinate monkeys even after withdrawal of the HFSD. Subordinate females demonstrated reduced glucocorticoid negative feedback, with post dexamethasone serum cortisol levels significantly predicting intake of the HFSD but not the LCD during the choice condition. The cortisol response to an acute stressor significantly predicted subsequent intake of a HFSD in all females. Continual exposure to the psychosocial stress of subordination in female monkeys results in excess caloric intake of foods that mimic a western dietary environment. In addition, this social stressor interacts with a history of HFSD intake to promote increased feeding even in a healthy dietary environment.
Psychosocial stress; Social subordination; Diet choice; Monkeys; Emotional feeding
Approximately 2 billion people currently suffer from intestinal helminth infections, which are typically chronic in nature and result in growth retardation, vitamin A deficiency, anemia and poor cognitive function. Such chronicity results from co-evolution between helminths and their mammalian hosts; however, the molecular mechanisms by which these organisms avert immune rejection are not clear. We have found that the natural murine helminth, Heligmosomoides polygyrus bakeri (Hp) elicits the secretion of IL-1β in vivo and in vitro and that this cytokine is critical for shaping a mucosal environment suited to helminth chronicity. Indeed in mice deficient for IL-1β (IL-1β−/−), or treated with the soluble IL-1βR antagonist, Anakinra, helminth infection results in enhanced type 2 immunity and accelerated parasite expulsion. IL-1β acts to decrease production of IL-25 and IL-33 at early time points following infection and parasite rejection was determined to require IL-25. Taken together, these data indicate that Hp promotes the release of host-derived IL-1β that suppresses the release of innate cytokines, resulting in suboptimal type 2 immunity and allowing pathogen chronicity.
Parasitic soil-transmitted helminths (STH) live, feed and mate within the intestine of their mammalian hosts. Infection is caused by ingestion of eggs and larvae or by active penetration of the skin by larvae from contaminated soil in poverty stricken areas lacking adequate sanitation. Infection with soil-transmitted helminths results in a wide range of symptoms including intestinal complications (diarrhea, abdominal pain), anemia, general malaise and nutritional deficiencies that negatively impact on working and learning capacities and impair physical growth. The host typically raises a strong type 2 immune response against the invading helminth; however, the majority of helminthes have developed the capacity to escape effective immunity and can remain chronically within the intestine for years. We explored the mechanisms responsible for helminth chronicity using a murine model of Heligmosomoides polygyrus bakeri (Hp) infection. We found that Hp is able to induce IL-1β secretion in the intestine and that this cytokine acts to suppress the production of the innate cytokines IL-25 and IL-33. Furthermore, we show that parasite rejection requires IL-25 indicating that suboptimal production of this cytokine in the presence of IL-1β is responsible for the ability of IL-1β to promote parasite chronicity. Our study provides new insights into the mechanisms used by helminths to establish chronic infections, and reveals a novel role for IL-1β in protective immunity.
Social subordination in female macaques is imposed by harassment and the threat of aggression and produces reduced control over one's social and physical environment and a dysregulation of the limbic-hypothalamic-pituitary-adrenal axis resembling that observed in people suffering from psychopathologies. These effects support the contention that this particular animal model is an ethologically relevant paradigm in which to investigate the etiology of stress-induced psychological illness related to women. Here, we sought to expand this model by performing a discriminate analysis (DA) on 33 variables within three domains; behavioral, metabolic/anthropomorphic, and neuroendocrine, collected from socially housed female rhesus monkeys in order to assess whether exposure to social subordination produces a distinct phenotype. A receiver operating characteristic (ROC) curve was also calculated to determine each domain's classification accuracy. DA found significant markers within each domain that differentiated dominant and subordinate females. Subordinate females received more aggression, showed more submissive behavior, and received less of affiliation from others than did dominant females. Metabolic differences included increased leptin, and reduced adiponectin in dominant compared to subordinate females. Dominant females exhibited increased sensitivity to hormonal stimulation with higher serum LH in response to estradiol, cortisol in response to ACTH, and increased glucocorticoid negative feedback. Serum oxytocin, CSF DOPAC and serum PACAP were all significantly higher in dominant females. ROC curve analysis accurately predicted social status in all three domains. Results suggest that socially house rhesus monkeys represent a cogent animal model in which to study the physiology and behavioral consequences of chronic psychosocial stress in humans.
social subordination; psychosocial stress; animal model; discriminate analysis
The extensive similarities between helminth proteins and allergens are thought to contribute to helminth-driven allergic sensitization.
To investigate the cross-reactivity between a major glutathione-S transferase (GST) allergen of cockroach (Bla g 5) and the GST of Wuchereria bancrofti (WbGST), a major lymphatic filarial pathogen of humans.
We compared the molecular and structural similarities between Bla g 5 and WbGST by in silico analysis and by linear epitope mapping. Levels of IgE, IgG and IgG4 antibodies were measured in filarial-infected and –uninfected patients. Mice were infected with Heligmosomoides bakeri (Hb) and skin tested for cross-reactive allergic responses.
These two proteins are 30% identical at the amino acid level with remarkable similarity in the N-terminal region and overall structural conservation based on predicted three-dimensional models. Filarial infection was associated with IgE, IgG, and IgG4 anti-Bla g 5 Ab production, with a significant correlation between Abs (irrespective of isotype) to Bla g 5 and WbGST (P < 0.0003). Pre-incubation of sera from cockroach allergic subjects with WbGST partially depleted (by 50 to 70%) anti-Bla g 5 IgE, IgG, and IgG4 Abs. IgE epitope mapping of Bla g 5 revealed that two linear N-terminal epitopes are highly conserved in WbGST corresponding to Bla g 5 peptides partially involved in the inhibition of WbGST binding. Finally, mice infected with Hb developed anti-HbGST IgE and showed immediate type skin test reactivity to Bla g 5.
These data demonstrate that helminth GST and the aeroallergen Bla g 5 share epitopes that can induce allergic cross-sensitization.
GST; cockroach; allergy; hygiene hypothesis; crossreactivity; filariasis
A diverse suite of effector immune responses provide protection against various pathogens. However, the array of effector responses must be immunologically regulated to limit pathogen- and immune-associated damage. CD4+Foxp3+ regulatory T cells (Treg) calibrate immune responses; however, how Treg cells adapt to control different effector responses is unclear. To investigate the molecular mechanism of Treg diversity we used whole genome expression profiling and next generation small RNA sequencing of Treg cells isolated from type-1 or type-2 inflamed tissue following Leishmania major or Schistosoma mansoni infection, respectively. In-silico analyses identified two miRNA “regulatory hubs” miR-10a and miR-182 as critical miRNAs in Th1- or Th2-associated Treg cells, respectively. Functionally and mechanistically, in-vitro and in-vivo systems identified that an IL-12/IFNγ axis regulated miR-10a and its putative transcription factor, Creb. Importantly, reduced miR-10a in Th1-associated Treg cells was critical for Treg function and controlled a suite of genes preventing IFNγ production. In contrast, IL-4 regulated miR-182 and cMaf in Th2-associed Treg cells, which mitigated IL-2 secretion, in part through repression of IL2-promoting genes. Together, this study indicates that CD4+Foxp3+ cells can be shaped by local environmental factors, which orchestrate distinct miRNA pathways preserving Treg stability and suppressor function.
The diversity of pathogens that the immune system encounters are controlled by a diverse suite of immunological effector responses. Preserving a well-controlled protective immune response is essential. Too vigorous an effector response can be as damaging as too little. Regulatory T cells (Treg) calibrate immune responses; however, how Treg cells adapt to control the diverse suite of effector responses is unclear. In this study we investigated the molecular identity of regulatory T cells that control distinct effector immune responses against two discrete pathogens, an intracellular parasitic protozoa, Leishmania major, and an extracellular helminth parasite, Schitsosoma mansoni. The two Treg populations studied were phenotypically and functionally different. We identified molecular pathways that influence this diversity and more specifically, we identified that two miRNAs (miR-182 and miR-10a) act as “regulatory hubs” critically controlling distinct properties within each Treg population. This is the first study identifying the upstream molecular pathways controlling Treg cell specialization and provides a new platform of Treg cell manipulation to fine-tune their function.
The Regulators of G protein signaling (RGS) protein superfamily negatively controls G-protein-coupled receptor (GPCR) signal transduction pathways. RGS16 is enriched in activated/effector T lymphocytes. Here, we show that RGS16 constrains pulmonary inflammation by regulating chemokine-induced T-cell trafficking in response to challenge with Schistosoma mansoni. Naïve Rgs16–/– mice were “primed” for inflammation by accumulation of CCR10+ T cells in the lung. Upon pathogen exposure, these mice developed more robust granulomatous lung fibrosis than wild-type (WT) counterparts. Distinct TH2 or putative TH17 subsets expressing CCR4 or CCR10 accumulated more rapidly in Rgs16–/– lungs following challenge and produced pro-inflammatory cytokines IL-13 and IL-17B. CCR4+ Rgs16–/– TH2 cells migrated excessively to CCL17 and localized aberrantly in challenged lungs. T lymphocytes were partially excluded from lung granulomas in Rgs16–/– mice, instead forming peribronchial/perivascular aggregates. Thus, RGS16-mediated confinement of T cells to Schistosome granulomas mitigates widespread cytokine-mediated pulmonary inflammation.
Chemokines; G proteins; RGS proteins; Schistosoma mansoni; fibrosis; TH2; TH17; cytokines
The last decade has seen an increase in investment and concerted efforts by the Malawi Ministry of Health and partners to control malaria disease. This report summarizes what is known about the burden of malaria and the strategies being implemented to control it in Malawi. Over the past five years, roll out of treatment and prevention efforts have been successful in the country, as demonstrated by increased use of insecticide treated nets, improved access to prompt and effective treatment and the initiation of pilot studies of indoor residual spraying. However, unlike other countries in the region, the recent data have not suggested a decrease in the burden of disease. We describe the environment in which the activities of Malawi’s International Center for Excellence in Malaria Research (ICEMR) will be carried out and provide the rationale for the clinical, entomological and molecular studies. Our approach is to establish consistent, stainable data collection systems that are embedded within the public health sector. Through standardized and long-term studies of hosts, parasites and vectors, we hope to contribute to assessment of malaria disease burden, the appropriate application of interventions and policies and provide both the data collection and the health care infrastructure to ultimately eliminate the disease.
Epidemiology; malaria; Anopheles; Malawi; artemisinin based combination therapy; insecticide treated nets; indoor residual spraying
Normal Mode Analysis is one of the most successful techniques for studying motions in proteins and macromolecules. It can provide information on the mechanism of protein functions, used to aid crystallography and NMR data reconstruction, and calculate protein free energies.
ΔΔPT is a toolbox allowing calculation of elastic network models and principle component analysis. It allows the analysis of pdb files or trajectories taken from; Gromacs, Amber, and DL_POLY. As well as calculation of the normal modes it also allows comparison of the modes with experimental protein motion, variation of modes with mutation or ligand binding, and calculation of molecular dynamic entropies.
This toolbox makes the respective tools available to a wide community of potential NMA users, and allows them unrivalled ability to analyse normal modes using a variety of techniques and current software.
Acute bacterial meningitis causes significant death and disability in children worldwide, with HIV recognized as an established risk factor for infection and negative outcomes. However, additional major risk factors for death and disability in pediatric acute bacterial meningitis remain unclear.
We conducted a retrospective analysis of case data from three departmental studies of acute bacterial meningitis involving 1,784 children <15 years old who attended Queen Elizabeth Central Hospital in Blantyre, Malawi during 1997--2010. Univariate and multivariate logistic regression models were used to estimate the effects of HIV seropositivity, impaired consciousness, and causative organism on death and severe sequelae.
Impaired consciousness or coma at the time of admission was strongly associated with death [Coma: OR = 14.4, 95%CI (9.42, 22.1)] and severe sequelae [Coma: OR = 3.27, 95%CI (2.02, 5.29)] in multivariate logistic regression models. HIV seropositivity was significantly associated with increased odds of death [OR = 1.65, 95%CI (1.20, 2.26)] but not with developing severe sequelae [OR = 0.88, 95%CI (0.56, 1.38)]. After adjustment, infection with Salmonella spp was associated with increased odds of death [OR = 2.11, 95%CI (1.06, 4.08)] and pneumococcal meningitis was associated with increased odds of severe sequelae [OR = 1.84, 95%CI (1.03, 3.29)].
Impaired consciousness and HIV infection increase the odds of death from ABM in Malawian children. Use of the pneumococcal conjugate vaccine could greatly reduce the burden of ABM in Malawi.
Streptococcus pneumoniae; pediatric; impaired consciousness; bacterial meningitis; Malawi
Facilitating motor learning in patients during clinical practice is complex, especially in people with cognitive impairments. General principles of motor learning are available for therapists to use in their practice. However, the translation of evidence from the different fields of motor learning for use in clinical practice is problematic due to lack of uniformity in definition and taxonomy of terms related to motor learning.
The objective of this paper was to describe the design of a Delphi technique to reach consensus on definitions, descriptions, and taxonomy used within motor learning and to explore experts’ opinions and experiences on the application of motor learning in practice.
A heterogeneous sample of at least 30 international experts on motor learning will be recruited. Their opinions regarding several central topics on motor learning using a Delphi technique will be collected in 3 sequential rounds. The questionnaires in the 3 rounds will be developed based on the literature and answers of experts from earlier rounds. Consensus will be reached when at least 70% of the experts agree on a certain topic. Free text comments and answers from open questions on opinions and experiences will be described and clustered into themes.
This study is currently ongoing. It is financially supported by Stichting Alliantie Innovatie (Innovation Alliance Foundation), RAAK-international (Registration number: 2011-3-33int).
The results of this study will enable us to summarize and categorize expert knowledge and experiences in a format that should be more accessible for therapists to use in support of their clinical practice. Unresolved aspects will direct future research.
motor learning; Delphi technique; clinical practice; consensus; definitions
High-performance metabolic profiling (HPMP) by Fourier-transform mass spectrometry coupled to liquid chromatography gives relative quantification of thousands of chemicals in biologic samples but has had little development for use in toxicology research. In principle, the approach could be useful to detect complex metabolic response patterns to toxicologic exposures and to detect unusual abundances or patterns of potentially toxic chemicals. As an initial study to develop these possible uses, we applied HPMP and bioinformatics analysis to plasma of humans, rhesus macaques, marmosets, pigs, sheep, rats and mice to determine: 1) whether more chemicals are detected in humans living in a less controlled environment than captive species, and 2) whether a subset of plasma chemicals with similar inter-species and intra-species variation could be identified for use in comparative toxicology. Results show that the number of chemicals detected was similar in humans (3221) and other species (range 2537 to 3373). Metabolite patterns were most similar within species and separated samples according to family and order. A total of 1485 chemicals were common to all species; 37% of these matched chemicals in human metabolomic databases and included chemicals in 137 out of 146 human metabolic pathways. Probability-based modularity clustering separated 644 chemicals, including many endogenous metabolites, with inter-species variation similar to intra-species variation. The remaining chemicals had greater inter-species variation and included environmental chemicals as well as GSH and methionine. Together, the data suggest that HPMP provides a platform that can be useful within human populations and controlled animal studies to simultaneously evaluate environmental exposures and biological responses to such exposures.
metabolomics; plasma; mass spectrometry; probability-based modularity clustering; exposome
The release of hematopoietic progenitor cells (HPC) from bone marrow (BM) is under tight homeostatic control. Under stress conditions, HPC migrate from BM and egress into circulation to participate in immune response, wound repair, or tissue regeneration. Hemorrhagic shock with resuscitation (HS/R), resulting from severe trauma and major surgery, promotes HPC mobilization from BM, which in turn affects post-HS immune responses. In this study, we investigated the mechanism of HS/R regulation of HPC mobilization from BM. Using a mouse HS/R model we demonstrate that the endogenous alarmin molecule high-mobility group box 1 (HMGB1) mediates HS/R-induced G-CSF secretion from macrophages (Mφ) in a RAGE signaling-dependent manner. Secreted G-CSF, in turn, induces HPC egress from BM. We also show that activation of β-adrenergic receptors on Mφ by catecholamine mediates the HS/R-induced release of HMGB1. These data indicate that HS/R, a global ischemia/reperfusion stimulus, regulates HPC mobilization through a series of interacting pathways that include neuro-endocrine and innate immune systems, in which Mφ play a central role.
G-CSF; HMGB1; RAGE; innate immune; β-adrenergic receptor
Salmonella enterica subsp. enterica serovar Enteritidis is a common food-borne pathogen, often associated with shell eggs and poultry. Here, we report draft genomes of 21 S. Enteritidis strains associated with or related to the U.S.-wide 2010 shell egg recall. Eleven of these genomes were from environmental isolates associated with the egg outbreak, and 10 were reference isolates from previous years, unrelated to the outbreak. The whole-genome sequence data for these 21 human pathogen strains are being released in conjunction with the newly formed 100K Genome Project.
Th2-driven lung inflammation increases Arginase 1 (Arg1) expression in alternatively-activated macrophages (AAMs). AAMs modulate T cell and wound healing responses and Arg1 might contribute to asthma pathogenesis by inhibiting nitric oxide production, regulating fibrosis, modulating arginine metabolism and restricting T cell proliferation. We used mice lacking Arg1 in myeloid cells to investigate the contribution of Arg1 to lung inflammation and pathophysiology. In six model systems encompassing acute and chronic Th2-mediated lung inflammation we observed neither a pathogenic nor protective role for myeloid-expressed Arg1. The number and composition of inflammatory cells in the airways and lungs, mucus secretion, collagen deposition, airway hyper-responsiveness, and T cell cytokine production were not altered if AAMs were deficient in Arg1 or simultaneously in both Arg1 and NOS2. Our results argue that Arg1 is a general feature of alternative activation but only selectively regulates Th2 responses. Therefore, attempts to experimentally or therapeutically inhibit arginase activity in the lung should be examined with caution.
Malaria control in the impoverished, highly endemic settings of sub-Saharan Africa remains a major public health challenge. Successes have been achieved only where sustained, concerted, multi-pronged interventions have been instituted. As one of the world’s poorest countries, Malawi experiences malaria incidence rates that have remained high despite a decade of gradually expanding and more intensive prevention efforts. The Malawi International Center for Excellence in Malaria Research (ICEMR) is beginning work to augment the knowledge base for reducing Plasmodium transmission and malaria morbidity and mortality. Among ICEMR goals, we intend to better assess patterns of infection and disease, and analyze transmission by Anopheles vector species in both urban and rural ecological settings. We will evaluate parasite population genetics and dynamics, transmission intensities and vector ecologies, social and environmental determinants of disease patterns and risk, and human-vector-parasite dynamics. Such context-specific information will help to focus appropriate prevention and treatment activities on efforts to control malaria in Malawi. In zones of intense and stable transmission, like Malawi,, elimination poses particularly thorny challenges - - and these challengers are different from those of traditional control and prevention activities. Working toward elimination will require knowledge of how various interventions impact on transmission as it approaches very low levels. At present, Malawi is faced with immediate, context-specific problems of scaling-up prevention and control activities simply to begin reducing infection and disease to tolerable levels. The research required to support these objectives is critically evaluated here.
Malaria eradication; Plasmodium transmission; Anopheles ecology; Africa infectious disease; vector control; public health policy
► α2M is an extracellular chaperone able to inhibit protein aggregation. ► Protease–α2M complexes can degrade amyloidogenic substrates or act as a chaperone. ► Activated α2M may play an important role in preventing protein deposition in vivo.
α2-Macroglobulin (α2M) is an extracellular chaperone that inhibits amorphous and fibrillar protein aggregation. The reaction of α2M with proteases results in an ‘activated’ conformation, where the proteases become covalently-linked within the interior of a cage-like structure formed by α2M. This study investigates, the effect of activation on the ability of α2M to inhibit amyloid formation by Aβ1–42 and I59T human lysozyme and shows that protease-activated α2M can act via two distinct mechanisms: (i) by trapping proteases that remain able to degrade polypeptide chains and (ii) by a chaperone action that prevents misfolded clients from continuing along the amyloid forming pathway.
Structured summary of protein interactions
Aβ1–42 and Aβ1–42 bind by fluorescence technology (View interaction)I59T lysozyme and I59T lysozyme bind by light scattering (View interaction)I59T lysozyme and I59T lysozyme bind by fluorescence technology (View interaction)Alpha-lactalbumin and Alpha-lactalbumin bind by fluorescence technology (View interaction)I59T lysozyme and I59T lysozyme bind by electron microscopy (View interaction)Aβ1–42 and Aβ1–42 bind by electron microscopy (View interaction)
α2M, α2-macroglobulin; LRP, lipoprotein receptor-related protein; trypsin-α2M, trypsin-activated α2M; (i)trypsin-α2M, trypsin-activated α2M treated with small molecule protease inhibitors; ThT, thioflavin T; α2-Macroglobulin; Extracellular chaperone; Amyloid disease; Human lysozyme; Aβ1–42
Facile laboratory tools are needed to augment identification in contamination events to trace the contamination back to the source (traceback) of Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis). Understanding the evolution and diversity within and among outbreak strains is the first step towards this goal. To this end, we collected 106 new S. Enteriditis isolates within S. Enteriditis Pulsed-Field Gel Electrophoresis (PFGE) pattern JEGX01.0004 and close relatives, and determined their genome sequences. Sources for these isolates spanned food, clinical and environmental farm sources collected during the 2010 S. Enteritidis shell egg outbreak in the United States along with closely related serovars, S. Dublin, S. Gallinarum biovar Pullorum and S. Gallinarum. Despite the highly homogeneous structure of this population, S. Enteritidis isolates examined in this study revealed thousands of SNP differences and numerous variable genes (n = 366). Twenty-one of these genes from the lineages leading to outbreak-associated samples had nonsynonymous (causing amino acid changes) changes and five genes are putatively involved in known Salmonella virulence pathways. While chromosome synteny and genome organization appeared to be stable among these isolates, genome size differences were observed due to variation in the presence or absence of several phages and plasmids, including phage RE-2010, phage P125109, plasmid pSEEE3072_19 (similar to pSENV), plasmid pOU1114 and two newly observed mobile plasmid elements pSEEE1729_15 and pSEEE0956_35. These differences produced modifications to the assembled bases for these draft genomes in the size range of approximately 4.6 to 4.8 mbp, with S. Dublin being larger (∼4.9 mbp) and S. Gallinarum smaller (4.55 mbp) when compared to S. Enteritidis. Finally, we identified variable S. Enteritidis genes associated with virulence pathways that may be useful markers for the development of rapid surveillance and typing methods, potentially aiding in traceback efforts during future outbreaks involving S. Enteritidis PFGE pattern JEGX01.0004.
Here we used a within-subject design to evaluate hypothalamic-pituitary-adrenal (HPA) activity following replacement of low and high physiological levels of testosterone (T) to adult, gonadally-suppressed, male rhesus macaques, and replacement with sex-specific low and high physiological doses of dihydrotestosterone (DHT) in the same adult males as well as in adult, gonadally-suppressed, female rhesus macaques. As indexes of HPA axis activation following T and DHT replacement, serum levels of cortisol (CORT) were measured before and following dexamethasone (DEX) inhibition, and corticotrophin-releasing factor (CRF) induced activation. Female monkeys were assessed for differences in response associated with dominant (DOM) and subordinate (SUB) social status. Data show that the high physiological dose of DHT significantly decreased basal CORT in both male and female monkeys irrespective of social status, but reduced CRF-stimulated CORT only in males. SUB female monkeys showed a trend towards increased CRF-stimulated CORT release under high-dose DHT replacement compared to DOM females or males given the same treatment, indicating that androgens likely have no influence on reducing HPA activation under chronic psychosocial stress in females. The normal circadian rhythm of CORT release was absent in placebo-replaced SUB and DOM females and was restored with low-dose DHT replacement. These results indicate that DHT significantly reduces CRF-stimulated CORT release only in male monkeys, and plays a role in maintaining circadian changes in CORT release in female monkeys.
HPA; stress; androgen; sex-differences; cortisol; monkey