Normal Physiological Situations Research Articles

Discovery of potential mTOR inhibitors from Cichorium intybus to find new candidate drugs targeting the pathological protein related to the breast cancer: an integrated computational approach.

Breast cancer is the most common malignancy among women. It is a complex condition with many subtypes based on the hormone receptor. The mammalian target of the rapamycin (mTOR) pathway regulates cell survival, metabolism, growth, and protein synthesis in response to upstream signals in both normal physiological and pathological situations, primarily in cancer. The objective of this study was to screen for a potential target to inhibit the mTOR using a variety of inhibitors derived from Cichorium intybus and to identify the one with the highest binding affinity for the receptor protein. Initially, AutoDock Vina was used to perform structure-based virtual screening, as protein-like interactions are critical in drug development. For the comparative analysis, 110 components of Cichorium intybus were employed and ten FDA-approved anticancer medicines, including everolimus, an mTOR inhibitor. Further, the drug-likeness and ADMET properties were investigated to evaluate the anti-breast cancer activity by applying Lipinski's rule of five to the selected molecules. The promising candidates were then subjected to three replica molecular dynamics simulations run for 100ns, followed by binding free energy estimation using MM-GBSA. The data were analyzed using root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), and protein-ligand interactions to determine the stability of the protein-ligand complex. Based on the results, taraxerone (98) revealed optimum binding affinities with mTOR, followed by stigmasterol (110) and rutin (104), which compared favorably to the control compounds. Subsequently, bioactive compounds derived from Cichorium intybus may serve as lead molecules for developing potent and effective mTOR inhibitors to treat breast cancer.

Protamine Sulfate Interacts with Partially Activated Forms of Factor V Which Contributes to Its Paradoxical Anticoagulant Effect

Unfractionated heparin (UFH) is a highly negatively charged molecule commonly used to prevent blood clotting in different clinical situations including cardiac and vascular surgeries. Its anticoagulant effect can be rapidly reversed or neutralized with protamine sulfate, a positively charged polypeptide that forms a stable interaction with UFH. Paradoxically, in vitro and in vivo studies have reported that protamine can also elicit an anticoagulant effect. Examination into this phenomenon (Ni Ainle, 2009; Bollinger, 2010) suggests that the anticoagulant activity of protamine relates to the inhibition of factor V (FV) activation and prothrombinase generation, but further mechanistic insights are lacking. FV circulates in blood as an inactive procofactor protein. Proteolytic cleavage of its central B-domain by thrombin converts it into an active cofactor (FVa) for factor Xa (FXa) in the prothrombinase complex. Our laboratory has established that the basic region (BR; residues 963-1008) and acidic region 2 (AR2; residues 1493-1537) within the B-domain are the minimal autoinhibitory sequences that keep FV inactive. Deletion of the BR yields a protein with cofactor-like properties in the absence of proteolysis, and the addition of the BR fragment in trans inhibits FV procoagulant function. Under normal physiological situations, naturally occurring ligands that mimic BR could re-engage forms of FV that harbor AR2 but lack BR (generically termed, FVAR). For example, it has been found that the C-terminus of TFPIα is homologous to FV BR and binds to physiologically relevant forms of FVAR including platelet FV as well as FV-short. FV-short represents less than 2% of plasma FV and is a splicing isoform initially found in the FV-East Texas family. It lacks most of the B-domain including BR and binds with high affinity to TFPIα. It is constitutively active, however the interaction with TFPIα converts it to a procofactor-like state, impairing its ability to bind to FXa and get proteolytically processed by thrombin. Due to its basic nature and observed anticoagulant effects, we hypothesized that protamine binds to the AR2 of FVAR species and inhibits cofactor function. We purified plasma derived FV (pd-FV), recombinant FVa, FV-short and FV-shortQQ (a thrombin resistant mutant) and employed functional assays to characterize the interaction with protamine. Using purified component assays we found that FV-short and FV-shortQQ activities are comparable to FVa when assembled in prothrombinase. However, protamine had a major inhibitory effect on FV-short cofactor function, but not FVa. Further, using fluorescence anisotropy measurements, we found that protamine could displace labeled BR bound to FV-short, indicating that the two molecules compete for similar binding sites on FV-short. In addition, western blotting analysis showed that protamine impaired proteolytic processing of FV species by thrombin or FXa. When added to pooled normal human plasma (NHP) or FV-deficient plasma (FV-DP) reconstituted with pd-FV or FV-short or the QQ variant, protamine caused a dose-dependent anticoagulant response on thrombin generation (TG). The inhibition was greater with FV-shortQQ, while protamine did not affect TG when FVa was employed. The addition of protamine (10 μg/ml) to heparinized (0.2 U/ml) plasma restored TG in NHP and FV-DP reconstituted with FV-short or FVa. Addition of higher concentrations of protamine to heparinized plasma resulted in the progressive reduction of TG for NHP and FV-short plasma, with no further effects on plasma reconstituted with FVa. We conclude that protamine, through molecular mimicry of FV BR and the C-terminal region of TFPIα, binds forms of FV that have an available AR2 such as FV-short. This interaction not only decreases procoagulant function of FVAR species and inhibits the formation of the prothrombinase complex but also delays their further processing by thrombin or FXa. These results suggest that, under physiological conditions, protamine exerts its anticoagulant effect by interacting with physiological relevant FVAR species. These include platelet-derived FV, partially cleaved FV, and FV-short. This study provides a molecular mechanism for the adverse anticoagulant effects of protamine and highlights the importance of physiologically relevant FVAR species. DisclosuresCamire:Pfizer: Consultancy, Patents & Royalties, Research Funding; Bayer: Consultancy, Research Funding; Spark Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Research Funding.

Innate lymphoid cell and adaptive immune cell cross-talk: A talk meant not to forget.

Innate lymphoid cells (ILCs) are a relatively new class of innate immune cells with phenotypical characters of lymphocytes but genotypically or functionally behave as typical innate immune cells. They have been classically divided into 3 groups (group 1 ILCs or ILC1s, group 2 ILCs or ILC2s, and group 3 ILCs or ILC3s). They serve as the first line of defense against invading pathogens and allergens at mucosal surfaces. The adaptive immune response works effectively in association with innate immunity as innate immune cells serve as APCs to directly stimulate the adaptive immune cells (various sets of T and Bcells). Additionally, innate immune cells also secrete various effector molecules, including cytokines or chemokines impacting the function, differentiation, proliferation, and reprogramming among adaptive immune cells to maintain immune homeostasis. Only superantigens do not require their processing by innate immune cells as they are recognized directly by Tcells and Bcells. Thus, a major emphasis of the current article is to describe the cross-talk between different ILCs and adaptive immune cells during different conditions varying from normal physiological situations to different infectious diseases to allergic asthma.

Mitochondrial DNA: A Key Regulator of Anti-Microbial Innate Immunity.

During the last few years, mitochondrial DNA has attained much attention as a modulator of immune responses. Due to common evolutionary origin, mitochondrial DNA shares various characteristic features with DNA of bacteria, as it consists of a remarkable number of unmethylated DNA as 2′-deoxyribose cytidine-phosphate-guanosine (CpG) islands. Due to this particular feature, mitochondrial DNA seems to be recognized as a pathogen-associated molecular pattern by the innate immune system. Under the normal physiological situation, mitochondrial DNA is enclosed in the double membrane structure of mitochondria. However, upon pathological conditions, it is usually released into the cytoplasm. Growing evidence suggests that this cytosolic mitochondrial DNA induces various innate immune signaling pathways involving NLRP3, toll-like receptor 9, and stimulator of interferon genes (STING) signaling, which participate in triggering downstream cascade and stimulating to produce effector molecules. Mitochondrial DNA is responsible for inflammatory diseases after stress and cellular damage. In addition, it is also involved in the anti-viral and anti-bacterial innate immunity. Thus, instead of entire mitochondrial importance in cellular metabolism and energy production, mitochondrial DNA seems to be essential in triggering innate anti-microbial immunity. Here, we describe existing knowledge on the involvement of mitochondrial DNA in the anti-microbial immunity by modulating the various immune signaling pathways.

AtIRE1C, an unconventional isoform of the UPR master regulator AtIRE1, is functionally associated with AtIRE1B in Arabidopsis gametogenesis.

The unfolded protein response (UPR), a highly conserved set of eukaryotic intracellular signaling cascades, controls the homeostasis of the endoplasmic reticulum (ER) in normal physiological growth and situations causing accumulation of potentially toxic levels of misfolded proteins in the ER, a condition known as ER stress. During evolution, eukaryotic lineages have acquired multiple UPR effectors, which have increased the pliability of cytoprotective responses to physiological and environmental stresses. The ER‐associated protein kinase and ribonuclease IRE1 is a UPR effector that is conserved from yeast to metazoans and plants. IRE1 assumes dispensable roles in growth in yeast but it is essential in mammals and plants. The Arabidopsis genome encodes two isoforms of IRE1, IRE1A and IRE1B, whose protein functional domains are conserved across eukaryotes. Here, we describe the identification of a third Arabidopsis IRE1 isoform, IRE1C. This protein lacks the ER lumenal domain that has been implicated in sensing ER stress in the IRE1 isoforms known to date. Through functional analyses, we demonstrate that IRE1C is not essential in growth and stress responses when deleted from the genome singularly or in combination with an IRE1A knockout allele. However, we found that IRE1C exerts an essential role in gametogenesis when IRE1B is also depleted. Our results identify a novel, plant‐specific IRE1 isoform and highlight that at least the control of gametogenesis in Arabidopsis requires an unexpected functional coordination of IRE1C and IRE1B. More broadly, our findings support the existence of a functional form of IRE1 that is required for development despite the remarkable absence of a protein domain that is critical for the function of other known IRE1 isoforms.

Metabolism

Article, see p 2144 In 1942, Rudolf Schoenheimer1 introduced the concept of The Dynamic State of Body Constituents . Schoenheimer was the first to use stable isotopes as labels in organic compounds destined for experiments in the mammalian body. From his results, he concluded that, “not only the fuel, but also the structural materials, are in a steady state of flux.”1 Today this concept is more relevant than ever. Along with well-documented changes in skeletal muscle, an important component of the mammalian response to exercise training is dynamic cardiac remodeling required to adapt cardiac output to peripheral demand. The process of physiological cardiac hypertrophy shares some mechanisms with the pathological hypertrophy seen in heart failure or the response to myocardial infarction. The latter process has been intensely studied, with several molecular signaling mechanisms elucidated (eg, the calcineurin nuclear factor of activated T cell signaling axis). However, less is known about the molecular mechanisms underlying cardiac plasticity under a range of normal physiological situations including exercise.2 Cardiac function is metabolically demanding, and although the heart is typically thought of as a metabolic omnivore, under steady-state conditions, the bulk of myocardial ATP requirements are met by mitochondrial β-oxidation of fatty acids.3 The pathways of cardiac metabolism remodel extensively in response to interventions both pathological (heart failure) and physiological (exercise training).4,5 A key question remains: Is cardiac metabolic remodeling merely a responsive epiphenomenon that accompanies structural hypertrophy or can it play a causative role in driving hypertrophy? In the case of pathological hypertrophy, mitochondrial DNA mutations are known to cause cardiomyopathy,6 and several mouse models of altered metabolism exhibit either pathological cardiac hypertrophy at baseline or …

Fire and water: Tumor cell adaptation to metabolic conditions

Lorenz Poellinger was a leader in understanding the effects of altered microenvironmental conditions in tumor biology and in normal physiology. His work examining the effects of hypoxia and the HIF transcription factors has expanded our understanding of the role of the microenvironment in affecting the behaviour of both normal and malignant cells. Furthermore, his work provides a model for understanding the adaptive responses to other metabolic stress conditions. By investigating the molecular mechanisms responsible for the adaptive responses to metabolic stress in normal physiological situations, across pathological conditions, and in different model organisms, his work shows the power of combining data from different model systems and physiological contexts. In cancers, it has become clear that in order to evolve to become an aggressive malignant disease, tumor cells must acquire the capacity to tolerate a host of abnormal and stressful metabolic conditions. This metabolic stress can be thought of as a fire that tumor cells must douse with enough water to survive, and may offer opportunities to exploit smoldering vulnerabilities in order to eradicate malignant cells.

A review of the 3D designing of scaffolds for tissue engineering with a focus on keratin protein

In tissue engineering scaffolds take the place of the natural extra cellular matrix (ECM). The natural ECM is the extracellular part of animal tissue that usually provides structural support to the animal cells in addition to performing various other important functions. The design aspect along with the choice of the material for the artificial scaffold is very crucial to cell differentiation, adhesion, proliferation, and the transport of the growth factors or other bio molecular signals. In addition to the material and design of the scaffolds, it is necessary to replicate the normal physiological situation if the scaffold has to function as an implant. The cells have to be located in the porous scaffold to form a three dimensional assembly. The article discusses the important factors to be considered while designing a scaffold for tissue engineering and regenerative medicine.

A Case of Complex PFO Leading to Ischemic Stroke: A Practical Clinical Pearl for Neurohospitalists.

Patent foramen ovale (PFO) has been proposed as a mechanism for cardioembolic stroke, especially in younger patient populations. Complex PFOs, with tunnel lengths exceeding 8 mm, lead to a higher risk of neurological sequelae than simple PFOs and may also be harder to detect with transthoracic echocardiography (TTE). In this article, we present a 29-year-old woman who, after polypharmacy overdose, developed deep venous thrombosis and multiple pulmonary emboli (PE) and subsequent cardioembolic stroke. Initial TTE showed intact interatrial septum with late appearance of agitated saline in the left atrium after the seventh cardiac cycle. Subsequent transesophageal echocardiography, after treatment of PE with an intravenous thrombolytic (alteplase) and anticoagulation with heparin, showed a complex PFO with a 19-mm overlap of the septum primum and secundum without active flow. It is suggested that this PFO allowed for flow only in the situation of elevated right heart strain with PE, causing cardioembolic stroke and detection of agitated saline in the left atrium on TTE. However, under normal physiological situations, which resumed after treatment of PE with alteplase and heparin, the PFO did not allow for flow. This case demonstrates the potential importance of recognition of complex PFOs in diagnosis and management of cardioembolic stroke.

Fisetin Inhibits Matrix Metalloproteinases and Reduces Tumor Cell Invasiveness and Endothelial Cell Tube Formation

Matrix metalloproteinases (MMPs) play an important role in tissue remodeling during normal physiological situations and pathological implications such as tumor invasion and metastasis. MMP inhibitors were screened from extracts of medicinal herbs by an enzymatic assay using the MMP-14 catalytic domain. Among samples tested, a methanol extract of the root of Dalbergia odorifera T. CHEN (Leguminosae) showed the strongest inhibitory activity. The inhibitory component was purified through fractionation methods and identified as fisetin, abundant in many fruits and vegetables. In addition to inhibition of MMP-14, fisetin inhibits MMP-1, MMP-3, MMP-7, and MMP-9, more efficiently than a naturally occurring MMP inhibitor tetracycline. Fisetin dose-dependently inhibits proliferation of fibrosarcoma HT-1080 cells and human umbilical vascular endothelial cells (HUVECs), MMP-14-mediated activation of proMMP-2 in HT-1080 cells, invasiveness of HT-1080 cells, and in vitro tube formation of HUVECs. Therefore, fisetin could be valuable as a chemopreventive agent against cancer and a lead compound for development of therapeutic MMP inhibitors.

A Simple Technique for a New Working Heterotopic Heart Transplantation Model in Rats

ObjectiveA new working model of heterotopic heart transplantation in rats was established using a simplified technique. Materials and methodsSprague-Dawley rats were used as donors and recipients. The donor left common carotid artery and left pulmonary artery were anastomosed to the recipient left renal artery and vein by a “sleeve and cuff” method, respectively. The donor left ventricle was blood volume loaded by anastomosing the left atrium to the recipient's abdominal aorta in end-to-side fashion. The characteristics of the donor heart were evaluated by palpating the abdominal wall of the rats. We examined the surgical success rate, changes in heart weight, and histology at 1 month after transplantation. ResultsThe model was attempted in 32 rats with the success rate of 93.7% (30/32); the 2 failed cases died due to postoperative bleeding. There was no significant difference in mean weight changes between the donor and native hearts at 1 month after transplantation (1.13 ± 0.13 g vs 1.09 ± 0.12 g, P = .244). The donor heart myocardium showed regularly shaped, unidirectional, healthy muscle similar to the native heart. ConclusionsThe technique was easily learned, allowing less recipient surgical stress. The hemodynamic performance appeared to be similar to the normal cardiac physiological situation, and thus may be more suitable for pre-clinical studies.

Selective impairment of emotion recognition through music in Parkinson's disease: does it suggest the existence of different networks for music and speech prosody processing?

Selective impairment of emotion recognition through music in Parkinson's disease: does it suggest the existence of different networks for music and speech prosody processing?

Retention and transmission of active transcription memory from progenitor to progeny cells via ligand‐modulated transcription factors: elucidation of a concept by BIOPIT model

Observations made in live cells have clearly demonstrated that agonist-activated steroid/nuclear receptors reorganize in the nucleoplasm into hundreds of discrete speckled structures commonly referred to as nuclear foci. Subsequent studies have shown that nuclear foci are formed only with agonist- and not with pure antagonist-bound receptors. Also, the other accessory components of transcriptional machinery co-localize in nuclear foci with the activated receptors, suggesting these to be active gene transcription sites. Recently, it has been observed that during mitosis nuclear foci present in interphase of progenitor cells co-migrate with condensing chromatin and are inherited into the progeny cells. Ensuing events imply that as memory, the cells inherit only a biomolecular blueprint of transcription status over to next generations to express and sustain their characteristic proteome. Thus, cells achieve self-renewal via mitosis but not without ensuring that the characteristic proteome and traits are distinctively preserved during this transcription phase. This mechanism, although somewhat analogous to epigenetic marking, differs in Nature since transcription factors themselves execute this transmission. To uphold the mechanistic distinctions the phenomenon has been termed BIOPIT (biomolecular imprints offered to progeny for inheritance of traits). The BIOPIT model proposed herein attempts to explain how the disruption of BIOPIT markings by therapeutic anti-hormones or endocrine disruptors over prolonged periods may lead to eradication of cellular transcription memory with deleterious cellular consequences. It is anticipated that our model has the potential to explain the concerted actions and consequences of ligand-receptor interactions with the chromatin in the perspective of normal and aberrant physiological situations.

Molecular Mechanism Underlying the Need for Three Cleavage Sites within the B-Domain to Activate Factor V by Thrombin

AbstractAbstract 2219Blood coagulation factor V (FV) is a multi-domain protein (A1-A2-B-A3-C1-C2) with little or no procoagulant activity and circulates in blood as a procofactor. Recent data indicate that specific sequences within the B-domain (963-1008) play a predominant role in keeping FV inactive. Removing these sequences via deletion or mutagenesis drives the activation of FV. In normal physiological situations, proteolytic processing of FV by thrombin within the B-domain (710-1545) ultimately removes these inhibitory sequences. Thrombin cleaves FV at three sites in a kinetically preferred order at Arg709, Arg1018 followed by Arg1545 to ultimately generate the active cofactor species, FVa consisting of a heavy and light chain. The need for three thrombin cleavage sites to generate an active cofactor species is not entirely obvious considering that RVV-V, a snake venom protease, activates FV following a single cleavage at Arg1545. Here we uncover new structure/function insights into how specific B-domain sequences restrict thrombin recognition of FV thereby forcing the need for three cleavage sites. To investigate this, we generated a panel of recombinant FV derivatives in BHK cells with different regions of the B-domain eliminated and combined functional measurements with SDS-PAGE to examine FV activation. As a control, we generated FV-1033 (residues 1034–1491 deleted) which is functionally equivalent to full-length FV and retains all three thrombin cleavage sites. Like FV, incubation of FV-1033 with thrombin resulted in rapid cleavage at Arg709, to generate the heavy chain (105 kDa) followed by cleavage at Arg1018 and Arg1545 to produce the light chain (74 kDa). In contrast to these results, elimination of the Arg1018 cleavage site via mutagenesis (FV-1033R1018Q) or deletion (FV-1015; 1016–1491 deleted) dramatically delayed cleavage at Arg1545 while proteolysis at Arg709 was unaltered compared to FV-1033. Control experiments with RVV-V revealed that FV-1033R1018Q and FV-1015 were rapidly cleaved at Arg1545 similar to FV-1033. These data are consistent with prior mutagenesis studies with full length FV and collectively suggest that the middle cleavage site somehow potentiates cleavage at 1545. However, further elimination of the B-domain using FV-902 (903-1491 deleted; Arg1018 not present) surprisingly restored rapid cleavage at Arg1545. These data suggest that sequences N-terminal to the 1018 site (902-1017) are involved in regulating thrombin cleavage at Arg1545 and that the purpose of cleavage at Arg1018 is to remove these constraints. In support of this, FV derivatives in which these sequences are exchanged with non-homologous regions of the FVIII B-domain were rapidly cleaved at Arg1545 whether or not Arg1018 was present. Furthermore, we were able to demonstrate that residues 964–1007 are the principal determinants in restricting thrombin cleavage at Arg1545. Functional measurements, including clotting assays, thrombin generation assays, and purified component systems revealed that FV derivatives which exhibited delayed cleavage at Arg1545 all have a markedly reduced ability to generate thrombin compared to FV-1033 or FV. Collectively these data demonstrate that FV cleavage site preferences are not only influenced by the geometric constraints imposed on thrombin but are also influenced in a dramatic way by specific B-domain sequences adjacent to Arg1018. These sequences, which conformationally restrict the ability of thrombin to access Arg1545, affect the rate and order of bond cleavage. Thus proteolysis at Arg1018 is required to alleviate these constraints allowing for accelerated cleavage at Arg1545 by thrombin. Furthermore, initial cleavage at Arg709 appears unaltered by any region of the B-domain as each of FV derivatives studied show equivalent processing at this site. These data provide new structure/function insights into the relationship between the removal of B-domain constraints and accessibility of thrombin cleavage sites which lead to the activation of FV. Disclosures:Camire: Pfizer: Patents & Royalties, Research Funding.

Lysophosphatidic Acid Level and the Incidence of Silent Brain Infarction in Patients with Nonvalvular Atrial Fibrillation

Lysophosphatidic acid (LPA), which is proposed to play an important role in normal physiological situations such as wound healing, vascular tone, vascular integrity and reproduction, may be involved in the etiology of some diseases such as atherosclerosis, cancer, obesity or myocardial infarction. Abnormal findings, including silent brain infarction (SBI), are frequently observed by magnetic resonance imaging (MRI) in patients with nonvalvular atrial fibrillation (NVAF). However, whether there is a relationship between LPA level and the prevalence of SBI has not been extensively studied. In the present study, the association between them was investigated. 235 patients with NVAF, 116 cases of SBI without NVAF and 120 cases of healthy volunteers (control group), who did not receive any antithrombotic therapy, were enrolled in this study. Plasma LPA levels in the NVAF with SBI group were significantly higher than that in the control group (p < 0.01), NVAF without SBI group (p < 0.01) and SBI without NVAF group (p < 0.01). The LPA levels are lower in the control group than in the NVAF without SBI and SBI without NVAF groups (p < 0.01), however, the latter two groups did not significantly differ from each other for LPA levels (p > 0.05) There were significant differences in the positive rate of platelet activation between each of the groups (p < 0.01). The positive rate of platelet activation was significantly higher in the NVAF with SBI group. We suggest that LPA might be a novel marker for estimation of the status of platelet activation and the risk factor for SBI onset in NVAF patients. We expected that plasma LPA levels could predict the occurrence of SBI in NVAF patients.

Autophagy: where next?

How far are we in understanding autophagy and the processes it regulates? What challenges lie ahead? If we decipher how autophagy affects disease, we might obtain new leads to fight it.

Killer Ig-Like Receptor Expression in Uterine NK Cells Is Biased toward Recognition of HLA-C and Alters with Gestational Age

Immunogenetic studies suggest that interactions between maternal killer Ig-like receptor (KIR) expressed by uterine NK (uNK) cells, and fetal HLA-C molecules on trophoblast, influence the success of human placentation. However, the exact functional response of fresh uNK cells to trophoblast HLA-C molecules is unknown. In this study, we show by quantitative RT-PCR and FACS that both activating and inhibitory KIR specific for HLA-C are expressed at higher levels and on an increased proportion of NK cells in the human decidua compared with blood. In contrast, expression of KIR3DL1/S1, which is specific for HLA-B, is similar in both NK cell populations. Remarkably, there is also a temporal change in the expression pattern of HLA-C-specific KIR, with a decline in both intensity of expression and frequency on uNK cells throughout the first trimester of pregnancy. This selective up-regulation of KIR has functional consequences because uNK cells show increased binding of HLA-C tetramers compared with blood NK cells. Ab cross-linking shows that these KIR are functional and results in increased cytokine secretion. uNK cells, therefore, exhibit a unique KIR profile that enhances their ability to recognize trophoblast cells expressing HLA-C at the materno-fetal interface. This is the first report to demonstrate selective regulation of KIR expression over time in vivo in a normal physiological situation and suggests that KIR expression by uNK cells is regulated by the tissue microenvironment in the decidua.

IMGT, the international ImMunoGeneTics information system(R)

The international ImMunoGeneTics information system® (IMGT) (http://imgt.cines.fr), created in 1989, by the Laboratoire d'ImmunoGénétique Moléculaire LIGM (Université Montpellier II and CNRS) at Montpellier, France, is a high-quality integrated knowledge resource specializing in the immunoglobulins (IGs), T cell receptors (TRs), major histocompatibility complex (MHC) of human and other vertebrates, and related proteins of the immune systems (RPI) that belong to the immunoglobulin superfamily (IgSF) and to the MHC superfamily (MhcSF). IMGT includes several sequence databases (IMGT/LIGM-DB, IMGT/PRIMER-DB, IMGT/PROTEIN-DB and IMGT/MHC-DB), one genome database (IMGT/GENE-DB) and one three-dimensional (3D) structure database (IMGT/3Dstructure-DB), Web resources comprising 8000 HTML pages (IMGT Marie-Paule page), and interactive tools. IMGT data are expertly annotated according to the rules of the IMGT Scientific chart, based on the IMGT-ONTOLOGY concepts. IMGT tools are particularly useful for the analysis of the IG and TR repertoires in normal physiological and pathological situations. IMGT is used in medical research (autoimmune diseases, infectious diseases, AIDS, leukemias, lymphomas, myelomas), veterinary research, biotechnology related to antibody engineering (phage displays, combinatorial libraries, chimeric, humanized and human antibodies), diagnostics (clonalities, detection and follow up of residual diseases) and therapeutical approaches (graft, immunotherapy and vaccinology). IMGT is freely available at http://imgt.cines.fr.

Increased expression of indoleamine 2,3-dioxygenase in murine malaria infection is predominantly localised to the vascular endothelium

Products of the kynurenine pathway of tryptophan metabolism have been implicated in the pathogenesis of murine and human cerebral malaria. Indoleamine 2,3-dioxygenase is the first and rate-limiting enzyme in this pathway and we have developed an immunohistochemical method for its detection in tissues from normal and malaria-infected mice. Mice were infected with Plasmodium berghei ANKA, a murine model of cerebral malaria, or P. berghei K173, a non-cerebral malaria model. Vascular endothelial cells were the primary sites of indoleamine 2,3-dioxygenase expression in both types of malaria infection and this response was systemic, with positive staining of vascular endothelium in all tissues examined. No indoleamine 2,3-dioxygenase expression was detected in uninfected or interferon-γ−/− mice. Corroborative data were obtained using quantitative reverse transcription PCR for indoleamine 2,3-dioxygenase mRNA. These results suggest that interferon-γ-dependent indoleamine 2,3-dioxygenase expression is part of a normal systemic host response to the parasite, perhaps performing some tissue protective functions that may become deranged under some circumstances and contribute to the pathogenesis of cerebral malaria. On the other hand, constitutive indoleamine 2,3-dioxygenase expression in the epididymis and the placenta was detected in both C57Bl/6 wild-type and interferon-γ−/− mice, suggesting a distinct regulatory mechanism for its induction in these normal physiological situations. Although increased indoleamine 2,3-dioxygenase production during murine malaria infection may not by itself cause cerebral pathology, metabolites of the kynurenine pathway may combine with other features of cerebral malaria, such as breakdown of the blood–brain barrier, to influence CNS function and contribute to the symptoms and pathology observed.

Mast cells and their role in the neuro‐immune‐endocrine axis

It has become clear that the immune and nervous systems communicate constantly to maintain homeostasis and a coordinated and continuing adaptive response to an ever‐changing environment. Evidence from mast cell nerve communication, as an example of this interaction, has been obtained in a variety of tissues and circumstances, most especially in the intestine and skin. Bidirectional communication has been shown in vivo, ex vivo, in vitro and in coculture experiments involving the two cell types. Examples will be given of these various situations and involve normal physiological situations and those involved in response to infection and inflammation as well as in response to ultraviolet light. More recent examples of the importance of mast cells in the regulation of central nervous activity including the secretion of hormones by the pituitary gland, and thereby the regulation of the HPA axis as well as involvement in behavioural change will be addressed. Through its potential communication with the nervous system, the mast cell can be regarded as a sentinel cell or receptor, especially located at surfaces exposed to the environment, which specifically and non‐specifically react to molecules and substances, foreign to the organism, so as to help orchestrate the complex and integrated responses required to maintain homeostasis.