Trafficking Receptors Research Articles

Insulin Signaling Differentially Regulates the Trafficking of Insulin and Amyloid Beta Peptides at the Blood-Brain Barrier.

The blood-brain barrier (BBB) is instrumental in clearing toxic metabolites from the brain, such as amyloid-β (Aβ) peptides, and in delivering essential nutrients to the brain, like insulin. In Alzheimer's disease (AD) brain, increased Aβ levels are paralleled by decreased insulin levels, which are accompanied by insulin signaling deficits at the BBB. Thus, we investigated the impact of insulin-like growth factor and insulin receptor (IGF1R and IR) signaling on Aβ and insulin trafficking at the BBB. Following intravenous infusion of an IGF1R/IR kinase inhibitor (AG1024) in wild-type mice, the BBB trafficking of 125I radiolabeled Aβ peptides and insulin was assessed by dynamic SPECT/CT imaging. The brain efflux of [125I]iodo-Aβ42 decreased upon AG1024 treatment. Additionally, the brain influx of [125I]iodoinsulin, [125I]iodo-Aβ42, [125I]iodo-Aβ40, and [125I]iodo-BSA (BBB integrity marker) was decreased, increased, unchanged, and unchanged, respectively, upon AG1024 treatment. Subsequent mechanistic studies were performed using an in vitro BBB cell model. The cell uptake of [125I]iodoinsulin, [125I]iodo-Aβ42, and [125I]iodo-Aβ40 was decreased, increased, and unchanged, respectively, upon AG1024 treatment. Further, AG1024 reduced the phosphorylation of insulin signaling kinases (Akt and Erk) and the membrane expression of Aβ and insulin trafficking receptors (LRP-1 and IR-β). These findings reveal that insulin signaling differentially regulates the BBB trafficking of Aβ peptides and insulin. Moreover, deficits in IGF1R and IR signaling, as observed in the brains of type II diabetes and AD patients, are expected to increase Aβ accumulation while decreasing insulin delivery to the brain, which has been linked to the progression of cognitive decline in AD.

Molecular basis for pH sensing in the KDEL trafficking receptor

Trafficking receptors control protein localization through the recognition of specific signal sequences that specify unique cellular locations. Differences in luminal pH are important for the vectorial trafficking of cargo receptors. The KDEL receptor is responsible for maintaining the integrity of the ER by retrieving luminally localized folding chaperones in a pH-dependent mechanism. Structural studies have revealed the end states of KDEL receptor activation and the mechanism of selective cargo binding. However, precisely how the KDEL receptor responds to changes in luminal pH remains unclear. To explain the mechanism of pH sensing, we combine analysis of X-ray crystal structures of the KDEL receptor at neutral and acidic pH with advanced computational methods and cell-based assays. We show a critical role for ordered water molecules that allows us to infer a direct connection between protonation in different cellular compartments and the consequent changes in the affinity of the receptor for cargo.

Unleashed monocytic engagement in Sézary syndrome during the combination of anti-CCR4 antibody with type I interferon

AbstractSézary syndrome (SS) is an aggressive leukemic expansion of skin-derived malignant CD4+ T cells. Drug monotherapy often results in disease relapse because of the heterogenous nature of malignant CD4+ T cells, but how therapies can be optimally combined remains unclear because of limitations in understanding the disease pathogenesis. We identified immunologic transitions that interlink mycosis fungoides with SS using single-cell transcriptome analysis in parallel with high-throughput T-cell receptor sequencing. Nascent peripheral CD4+ T cells acquired a distinct profile of transcription factors and trafficking receptors that gave rise to antigenically mature Sézary cells. The emergence of malignant CD4+ T cells coincided with the accumulation of dysfunctional monocytes with impaired fragment crystallizable γ-dependent phagocytosis, decreased responsiveness to cytokine stimulation, and limited repertoire of intercellular interactions with Sézary cells. Type I interferon supplementation when combined with a monoclonal antibody targeting the chemokine receptor type 4 (CCR4), unleashed monocyte induced phagocytosis and eradication of Sézary cells in vitro. In turn, coadministration of interferon-α with the US Food and Drug Administration–approved anti-CCR4 antibody, mogamulizumab, in patients with SS induced marked depletion of peripheral malignant CD4+ T cells. Importantly, residual CD4+ T cells after Sézary cell ablation lacked any immunologic shifts. These findings collectively unveil an auxiliary role for augmenting monocytic activity during mogamulizumab therapy in the treatment of SS and underscore the importance of targeted combination therapy in this disease.

Exhausted Tumor-infiltrating CD39+CD103+ CD8+ T Cells Unveil Potential for Increased Survival in Human Pancreatic Cancer.

Patients with pancreatic cancer with a high proportion of CD39+CD103+ CD8+ T cells exhibiting a tumor-reactive phenotype have improved survival rates, suggesting their potential utility in selecting candidates for immunotherapy trials.

Pharmacological activation of ATF6 remodels the proteostasis network to rescue pathogenic GABAA receptors

BackgroundGenetic variants in the subunits of the gamma-aminobutyric acid type A (GABAA) receptors are implicated in the onset of multiple pathologic conditions including genetic epilepsy. Previous work showed that pathogenic GABAA subunits promote misfolding and inefficient assembly of the GABAA receptors, limiting receptor expression and activity at the plasma membrane. However, GABAA receptors containing variant subunits can retain activity, indicating that enhancing the folding, assembly, and trafficking of these variant receptors offers a potential opportunity to mitigate pathology associated with genetic epilepsy.ResultsHere, we demonstrate that pharmacologically enhancing endoplasmic reticulum (ER) proteostasis using small molecule activators of the ATF6 (Activating Transcription Factor 6) signaling arm of the unfolded protein response (UPR) increases the assembly, trafficking, and surface expression of variant GABAA receptors. These improvements are attributed to ATF6-dependent remodeling of the ER proteostasis environment, which increases protein levels of pro-folding ER proteostasis factors including the ER chaperone BiP (Immunoglobulin Binding Protein) and trafficking receptors, such as LMAN1 (Lectin Mannose-Binding 1) and enhances their interactions with GABAA receptors. Importantly, we further show that pharmacologic ATF6 activators increase the activity of GABAA receptors at the cell surface, revealing the potential for this strategy to restore receptor activity to levels that could mitigate disease pathogenesis.ConclusionsThese results indicate that pharmacologic ATF6 activators offer an opportunity to restore GABAA receptor activity in diseases including genetic epilepsy and point to the potential for similar pharmacologic enhancement of ER proteostasis to improve trafficking of other disease-associated variant ion channels implicated in etiologically-diverse diseases.

Enhanced Expression of CXCR4 Facilitates the Trafficking of Anti-c-Kit Chimeric Antigen Receptor (CAR) T Cells to Bone Marrow and Achieves Effective Donor Stem Cell Engraftment

Allogeneic hematopoietic stem cell (HSC) transplantation is one of the curative therapeutic options for patients with a variety of inherited disorders of blood cells, including immune deficiencies and hemoglobinopathies. In addition, considerable progress has been made toward achieving clinical benefit from autologous HSC ex vivo gene therapy for some of these disorders. Generally, some level of conditioning using chemotherapy and/or radiation is needed to achieve the required engraftment of allogeneic HSC or gene corrected autologous HSC. There is considerable interest in finding less toxic and more focused approaches to achieve the conditioning. Promising results were observed using antibody-based approaches including anti-c-kit (CD117) or anti-CD45 which directly target HSCs, and these results can be enhanced by linking the antibody to a toxin such as saponin. Here, we explored a related approach in mouse models in which chimeric antigen receptor (CAR)-T cells targeting c-kit (c-kit CAR-T cells) were employed as conditioning to achieve significant engraftment of congenic HSCs. Our initial attempts at efficient conditioning with c-kit CAR-T cells failed because there was insufficient trafficking of CAR-T cells to bone marrow (BM) and insufficient CAR-T cell expansion in vivo and because we did not eliminate the CAR-T cells before transplanting congenic HSCs.To address these barriers, before injecting CAR-T cells (derived from C57BL/6 Thy1.1/CD45.2 mouse spleen on Day1 and transduced with CAR retrovirus on Day2) we pre-treated the recipient mice (Thy1.2/CD45.2) with low-dose cyclophosphamide (CY, 125 mg/kg; Day2) and co-transduced the c-kit CAR-T cells with a CXCR4 (CD184) expression vector (Day2), followed by injection of 5×106 CAR-T cells on Day3. We later removed these CAR-T cells by treating the mice with anti-Thy1.1 antibody (Ab) on Day11 prior to HSC transplantation from congenic Thy1.2/CD45.1 mice (Day12; 3×106 cells/mouse).After single CAR retrovirus transduction, >90% of T cells expressed CAR. When used in vitro, CAR-T cells efficiently depleted BM c-kit+ population (10.5% reduced to 1.6%) and completely suppressed colony formation in nitrocellulose medium. In initial in vivo studies, we used a luciferase marker in the CAR-T cells to allow whole body imaging in addition to flow cytometry (FACS) of BM to assess trafficking. With no pre-treatment of mice, both in vivo imaging and FACS demonstrated poor trafficking of CAR-T cells to BM (< 1% of cells), and there was no decrease of the BM c-kit+ population. In contrast, pre-treatment with low-dose CY and overexpression of CXCR4 on the CAR-T cell surface improved the CAR-T cell expansion in vivo and the migration into BM (mean Thy1.1+ cells, 11.9%; n= 5), and this was associated with significant in vivo depletion of BM c-kit+ population (9.0% reduced to 0.0%). Severe pancytopenia was confirmed in peripheral blood (Hgb 2.2 g/dL compared to the normal, 13.0 g/dL) along with aplastic BM (Figure A), and these mice died within 4 weeks without BM transplant. Subsequent injection of anti-Thy1.1 Ab completely depleted CAR-T cells in viv o. When congenic BM cells were transplanted into mice conditioned in this manner (CY+CAR-T+Thy1.1 Ab), these mice achieved complete recovery of hematopoiesis with significant engraftment of donor BM in all lineages in peripheral blood (Figure B) and long-term HSCs in BM (> 20 % donor chimerism).Our findings provide proof-of-concept that c-kit CAR-T cells can be used to achieve sufficient conditioning to allow donor chimerism after congenic transplantation without use of high-dose chemotherapy or radiation. Low-dose CY was required to achieve the reduction of host T cells and stimulate in vivo expansion of CAR-T cells. A key element to achieve BM HSC depletion was the co-transduction of CXCR4 that greatly increased trafficking of the CAR-T cells to BM. This finding may be one of the most important aspects of this study, with broader implications for the CAR-T cell field in suggesting that use of trafficking receptors or ligands might be generalizable as a method to enhance targeting to designated organs or solid tumors. In summary, our studies add to the list of tools that should be further explored in the effort to seek less toxic conditioning regimens for BM transplantation. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Brief in vitro IL-12 conditioning of CD8 + T Cells for anticancer adoptive T cell therapy.

Cancer immunotherapy represents a potential treatment approach through non-specific and specific enhancement of the immune responses. Adoptive cell therapy (ACT) is a potential modality of immunotherapy that depends on harvesting T cells from the tumor-bearing host, activating them in vitro and infusing them back to the same host. Several cytokines, in particular IL-2, IL-7 and IL-15, have been used to enhance survival T cells in vitro. Although effective, conditioning of T cells in vitro with these cytokines requires long-term culture which results in the loss of expression of their trafficking receptors mainly CD62L. It also results in exhaustion of the activated T cells and reduction in their functions upon adoptive transfer in vivo. Our recent studies and those of other groups showed that brief (3days) conditioning of CD8+ T cells by IL-12 in vitro can result in enhancing function of tumor-reactive CD8+ T cells. Adoptive transfer of these IL-12-conditioned CD8+ T cells into tumor-bearing mice, preconditioned with cyclophosphamide, 1day before ACT, induced tumor eradication that was associated with generation of tumor-specific memory response. In this review, we summarize studies that indicated to the superiority of IL-12 as a potential cytokine for conditioning T cells for ACT. In addition, we discuss some of the cellular and molecular mechanisms that govern how IL-12 programs CD8+ T cells to enhance their functionality especially in vitro and its implication in combination with other ACT modalities, opening a avenue for the clinical application of this cytokine.

Single-Cell Sequencing Reveals the Transcriptome and TCR Characteristics of pTregs and in vitro Expanded iTregs.

Regulatory T cells (Tregs) play a critical role in the maintenance of immune tolerance and tumor evasion. However, the relative low proportion of these cells in peripheral blood and tissues has hindered many studies. We sought to establish a rapamycin-based in vitro Treg expansion procedure in patients diagnosed with colorectal cancer and perform single-cell sequencing to explore the characteristics of Treg cells. CD25+ cells enriched from peripheral blood mononuclear cells (PBMC) of colorectal tumor patients were cultured in X-VIVO15 medium, supplemented with 5% human AB serum, L-glutamine, rapamycin, interleukin-2 (IL-2), and Dynabeads human Treg expander for 21 days to expand Tregs. Treg cells with satisfactory phenotype and function were successfully expanded from CD4+CD25+ cells in patients with colorectal cancer. The median expansion fold was 75 (range, 20–105-fold), and >90.0% of the harvest cells were CD4+CD25+CD127dim/− cells. The ratio of CD4+CD25+Foxp3+ cells exceeded 60%. Functional assays showed that iTregs significantly inhibited CD8+T cell proliferation in vitro. Single-cell sequencing showed that the transcriptome of pTreg (CD4+CD25+CD127dim/− cells isolated from PBMC of colorectal cancer patients) and iTreg (CD4+CD25+CD127dim/− cells expanded in vitro according to the above regimen) cells were interlaced. pTregs exhibited enhanced suppressive function, whereas iTregs exhibited increased proliferative capacity. TCR repertoire analysis indicated minimal overlap between pTregs and iTregs. Pseudo-time trajectory analysis of Tregs revealed that pTregs were a continuum composed of three main branches: activated/effector, resting and proliferative Tregs. In contrast, in vitro expanded iTregs were a mixture of proliferating and activated/effector cells. The expression of trafficking receptors was also different in pTregs and iTregs. Various chemokine receptors were upregulated in pTregs. Activated effector pTregs overexpressed the chemokine receptor CCR10, which was not expressed in iTregs. The chemokine CCL28 was overexpressed in colorectal cancer and associated with poor prognosis. CCR10 interacted with CCL28 to mediate the recruitment of Treg into tumors and accelerated tumor progression. Depletion of CCR10+Treg cells from tumor microenvironment (TME) could be used as an effective treatment strategy for colorectal cancer patients. Our data distinguished the transcriptomic characteristics of different subsets of Treg cells and revealed the context-dependent functions of different populations of Treg cells, which was crucial to the development of alternative therapeutic strategies for Treg cells in autoimmune disease and cancer.

Molecular basis for KDEL-mediated retrieval of escaped ER-resident proteins - SWEET talking the COPs.

ABSTRACTProtein localisation in the cell is controlled through the function of trafficking receptors, which recognise specific signal sequences and direct cargo proteins to different locations. The KDEL receptor (KDELR) was one of the first intracellular trafficking receptors identified and plays an essential role in maintaining the integrity of the early secretory pathway. The receptor recognises variants of a canonical C-terminal Lys-Asp-Glu-Leu (KDEL) signal sequence on ER-resident proteins when these escape to the Golgi, and targets these proteins to COPI- coated vesicles for retrograde transport back to the ER. The empty receptor is then recycled from the ER back to the Golgi by COPII-coated vesicles. Crystal structures of the KDELR show that it is structurally related to the PQ-loop family of transporters that are found in both pro- and eukaryotes, and shuttle sugars, amino acids and vitamins across cellular membranes. Furthermore, analogous to PQ-loop transporters, the KDELR undergoes a pH-dependent and ligand-regulated conformational cycle. Here, we propose that the striking structural similarity between the KDELR and PQ-loop transporters reveals a connection between transport and trafficking in the cell, with important implications for understanding trafficking receptor evolution and function.

Large-Scale HLA Tetramer Tracking of T Cells during Dengue Infection Reveals Broad Acute Activation and Differentiation into Two Memory Cell Fates

T cells play important multifaceted roles during dengue infection, and understanding their responses is important for defining correlates of protective immunity and identifying effective vaccine antigens. Using mass cytometry and a highly multiplexed peptide-HLA (human leukocyte antigen) tetramer staining strategy, we probed Tcells from dengue patients-a total of 430 dengue and control candidate epitopes-together with key markers of activation, trafficking, and differentiation. During acute disease, dengue-specific CD8+ Tcells expressed a distinct profile of activation and trafficking receptors thatdistinguished them from non-dengue-specific Tcells. During convalescence, dengue-specific Tcells differentiated into two major cell fates, CD57+ CD127--resembling terminally differentiated senescent memory cells and CD127+ CD57--resembling proliferation-capable memory cells. Validation in an independent cohort showed that these subsets remained at elevated frequencies up to one year after infection. These analyses aid our understanding of the generation of Tcell memory in dengue infection or vaccination.

Guidance factors orchestrating regulatory T cell positioning in tissues during development, homeostasis, and response.

Over their lifetime, regulatory T cells (Treg) recalibrate their expression of trafficking receptors multiple times as they progress through development, respond to immune challenges, or adapt to the requirements of functioning in various non-lymphoid tissue environments. These trafficking receptors, which include chemokine receptors and other G-protein coupled receptors, integrins, as well as selectins and their ligands, enable Treg not only to enter appropriate tissues from the bloodstream via post-capillary venules, but also to navigate these tissues to locally execute their immune-regulatory functions, and finally to seek out the right antigen-presenting cells and interact with these, in part in order to receive the signals that sustain their survival, proliferation, and functional activity, in part in order to execute their immuno-regulatory function by altering antigen presenting cell function. Here, we will review our current knowledge of when and in what ways Treg alter their trafficking properties. We will focus on the chemokine system and try to identify specialized, non-redundant roles of individual receptors as well as similarities and differences to the conventional T cell compartment.

Characterization of CTLA4 Trafficking and Implications for Its Function

CTLA4 is an essential negative regulator of T-cell immune responses and a key checkpoint regulating autoimmunity and antitumor responses. Genetic mutations resulting in quantitative defects in the CTLA4 pathway are also associated with the development of immune dysregulation syndromes in humans. It has been proposed that CTLA4 functions to remove its ligands CD80 and CD86 from opposing cells by a process known as transendocytosis. A quantitative characterization of CTLA4 synthesis, endocytosis, degradation, and recycling and how these affect its function is currently lacking. In a combined in vitro and in silico study, we developed a mathematical model and identified these trafficking parameters. Our model predicts optimal ligand removal in an intermediate affinity range. The intracellular CTLA4 pool as well as fast internalization, recovery of free CTLA4 from internalized complexes, and recycling is critical for sustained functionality. CD80-CTLA4 interactions are predicted to dominate over CD86-CTLA4. Implications of these findings in the context of control of antigen-presenting cells by regulatory T cells and of pathologic genetic deficiencies are discussed. The presented mathematical model can be reused in the community beyond these questions to better understand other trafficking receptors and study the impact of CTLA4 targeting drugs.

Myeloid-Derived Suppressor Cells and Pulmonary Hypertension

Myeloid–derived suppressor cells (MDSCs) comprised a heterogeneous subset of bone marrow–derived myeloid cells, best studied in cancer research, that are increasingly implicated in the pathogenesis of pulmonary vascular remodeling and the development of pulmonary hypertension. Stem cell transplantation represents one extreme interventional strategy for ablating the myeloid compartment but poses a number of translational challenges. There remains an outstanding need for additional therapeutic targets to impact MDSC function, including the potential to alter interactions with innate and adaptive immune subsets, or alternatively, alter trafficking receptors, metabolic pathways, and transcription factor signaling with readily available and safe drugs. In this review, we summarize the current literature on the role of myeloid cells in the development of pulmonary hypertension, first in pulmonary circulation changes associated with myelodysplastic syndromes, and then by examining intrinsic myeloid cell changes that contribute to disease progression in pulmonary hypertension. We then outline several tractable targets and pathways relevant to pulmonary hypertension via MDSC regulation. Identifying these MDSC-regulated effectors is part of an ongoing effort to impact the field of pulmonary hypertension research through identification of myeloid compartment-specific therapeutic applications in the treatment of pulmonary vasculopathies.

Abstract 5006: Kit-dependent tissue resident macrophage progenitors drive cancer progression

Abstract Macrophages play a key role in promoting tumor growth and resistance to therapy. Here we show that tissue-resident as well as bone marrow-derived macrophages play critical roles in promoting tumor growth. Tissue-resident macrophages were recently shown to originate in the yolk sac or fetal liver during embryogenesis; these cells self-maintain in post-natal tissues independent of hematopoietic stem cells. Tissue-resident macrophages and bone marrow-derived macrophages rapidly accumulate in tumors where they play independent roles in promoting tumor growth. Tissue-resident macrophages are CD11b+Gr1-F4/80hiCX3CR1hiCCR2-Ki67+ cells that accumulate in tumors independently of trafficking receptors. In contrast, bone marrow-derived CD11b+Gr1+F4/80loCX3CR1loCCR2+ macrophages accumulate in tumors in an integrin α4β1/αLβ2 and CCR2 or CXCR4-dependent manner. Gene expression studies show that tumor-associated tissue-resident macrophages are highly proliferative, immune-suppressive myeloid cells that are less proangiogenic than bone marrow-derived macrophages. Our studies show that tumor cells induce the expansion of tissue-resident macrophage progenitor cells by secreting stem cell factor and mCSF. Here we identify a Kit/KitL-dependent tissue-resident macrophage progenitor that is abundant in tumors but not in normal tissues. Notably, tumor growth and colony-forming activity are significantly inhibited in mice treated with SCF and Kit inhibitors. Tumors adoptively transferred with tissue-resident macrophage progenitor cells exhibited a significant growth advantage over control tumors. Furthermore, Kit inhibitors synergize with other immune therapy regimens to suppress tumor growth. Our studies show that tissue-resident macrophage progenitors promote aggressive tumor growth that can be targeted by Kit/SCF inhibition. Citation Format: Paulina Pathria, Hideyuki Takahashi, Megan Kaneda, Judith A. Varner. Kit-dependent tissue resident macrophage progenitors drive cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5006.

SORCS1 and SORCS3 control energy balance and orexigenic peptide production

SORCS1 and SORCS3 are two related sorting receptors expressed in neurons of the arcuate nucleus of the hypothalamus. Using mouse models with individual or dual receptor deficiencies, we document a previously unknown function of these receptors in central control of metabolism. Specifically, SORCS1 and SORCS3 act as intracellular trafficking receptors for tropomyosin‐related kinase B to attenuate signaling by brain‐derived neurotrophic factor, a potent regulator of energy homeostasis. Loss of the joint action of SORCS1 and SORCS3 in mutant mice results in excessive production of the orexigenic neuropeptide agouti‐related peptide and in a state of chronic energy excess characterized by enhanced food intake, decreased locomotor activity, diminished usage of lipids as metabolic fuel, and increased adiposity, albeit at overall reduced body weight. Our findings highlight a novel concept in regulation of the melanocortin system and the role played by trafficking receptors SORCS1 and SORCS3 in this process.

DuCNoC: A High-Throughput FPGA-Based NoC Simulator Using Dual-Clock Lightweight Router Micro-Architecture

On-chip interconnections play an important role in multi/many-processor systems-on-chip (MPSoCs). In order to achieve efficient optimization, each specific application must utilize a specific architecture, and consequently a specific interconnection network. For design space exploration and finding the best NoC solution for each specific application, a fast and flexible NoC simulator is necessary, especially for large design spaces. In this paper, we present an FPGA-based NoC co-simulator, which is able to be configured via software. In our proposed NoC simulator, entitled DuCNoC , we implement a Dual-Clock router micro-architecture, which demonstrates 75x $-$ 350x speed-up against BOOKSIM. Additionally, we implement a two-layer configurable global interconnection in our proposed architecture to (1) reduce virtualization time overhead, (2) make an efficient trade-off between the resource utilization and simulation time of the whole simulator, and especially (3) provide the capability of simulating irregular topologies. Migration of some important sub-modules like traffic generators (TGs) and traffic receptors (TRs) to software side, and implementing a dual-clock context switching in virtualization are other major features of DuCNoC. Thanks to its dual-clock router micro-architecture, as well as TGs and TRs migration to software side, DuCNoC can simulate a 100-node (10 $\times$ 10) non-virtualized or a 2048-node virtualized mesh network on Xilinx Zynq-7000.

Interleukin-2 and other cytokines in candidiasis: expression, clinical significance, and future therapeutic targets

Susceptibility to Candida spp. infection is largely determined by the status of host immunity, whether immunocompromised/immunodeficient or immunocompetent. Interleukin-2 (IL-2), a potent lymphoid cell growth factor, is a four-α-helix bundle cytokine induced by activated T cells with two important roles: the activation and maintenance of immune responses, and lymphocyte production and differentiation. We reviewed the roles of cytokines as immune stimulators and suppressors of Candida spp. infections as an update on this continuously evolving field. We performed a comprehensive search of the Cochrane Central Register of Controlled Trials, Medline (PubMed), and Embase databases for articles published from March 2010 to March 2016 using the following search terms: interleukins, interleukin-2, Candida spp., and immunosuppression. Data from our own studies were also reviewed. Here, we provide an overview focusing on the ability of IL-2 to induce a large panel of trafficking receptors in skin inflammation and control T helper (Th)2 cytokine production in response to contact with Candida spp. Immunocompromised patients have reduced capacity to secrete Th1-related cytokines such as IL-2. The ability to secrete the Th1-related cytokine IL-2 is low in immunocompromised patients. This prevents an efficient Th1 immune response to Candida spp. antigens, making immunocompromised patients more susceptible to candidal infections.

Differences between chronic lymphocytic leukaemia and small lymphocytic lymphoma cells by proteomic profiling and SNP microarray analysis

The majority of malignant cells in chronic lymphocytic leukaemia (CLL) circulate in the peripheral blood whereas small lymphocytic lymphoma (SLL) cells reside in tissues. The aim of this study was to detect differences in chemokine receptor expression, DNA single nucleotide polymorphism (SNP) microarray analysis and proteomic profiling to help elucidate why the cells remain in their respective environments. We identified by flow cytometric studies of chemokine receptors and DNA SNP microarray analysis significant differences between cells from CLL and SLL patients. Proteomic analysis revealed two potential markers (m/z 3091 and 8707) to distinguish the two disorders. There was a significantly greater expression of leucocyte trafficking receptor CXCR3 (CD183) and migration and homing receptor CXCR4 (CD184), and significantly lower expression of cell adhesion molecule integrin α4 chain (CD49d), on CLL cells, compared with SLL cells. Conversely, SNP microarrays revealed greater numbers of copy-neutral loss of heterozygosity chromosomal aberrations, as well as gross chromosomal aberrations, in the SLL group, compared with the CLL group. These findings revealed that there was a significantly greater expression of trafficking, migration and homing receptors and significantly lower expression of adhesion molecules on CLL cells than on SLL cells, and that SLL may be a more progressive disease than CLL, with a more complex genotype.

An Analysis of Trafficking Receptors Shows that CD44 and P-Selectin Glycoprotein Ligand-1 Collectively Control the Migration of Activated Human T-Cells.

Selectins guide the traffic of activated T-cells through the blood stream by mediating their tethering and rolling onto inflamed endothelium, in this way acting as beacons to help navigate them to sites of inflammation. Here, we present a comprehensive analysis of E-selectin ligands expressed on activated human T-cells. We identified several novel glycoproteins that function as E-selectin ligands. Specifically, we compared the role of P-selectin glycoprotein ligand-1 (PSGL-1) and CD43, known E-selectin ligands, to CD44, a ligand that has not previously been characterized as an E-selectin ligand on activated human T-cells. We showed that CD44 acts as a functional E-selectin ligand when expressed on both CD4+ and CD8+ T-cells. Moreover, the CD44 protein carries a binding epitope identifying it as hematopoietic cell E- and/or L-selectin ligand (HCELL). Furthermore, by knocking down these ligands individually or together in primary activated human T-cells, we demonstrated that CD44/HCELL, and not CD43, cooperates with PSGL-1 as a major E-selectin ligand. Additionally, we demonstrated the relevance of our findings to chronic autoimmune disease, by showing that CD44/HCELL and PSGL-1, but not CD43, from T-cells isolated from psoriasis patients, bind E-selectin.

Information-dense analysis for information-dense understanding

Using mass cytometry coupled with cellular barcoding, Wong et al . (1) report a high-dimensional map of human T-cell trafficking receptors and cytokine profiles in several different tissues. Specifically, the authors analyzed T cells from eight human organs, including healthy donors and patients with different underlying conditions, with a range of three to five individual samples per organ. Perhaps unsurprisingly, their findings highlight the dynamic and complex nature of T cells in different organs and stress the importance of looking beyond peripheral blood when analyzing human T cell phenotype and function.