Activation of dual T cell signaling pathways by the chemokine RANTES

Exploring causal association between circulating inflammatory cytokines and functional outcomes following ischemic stroke: A bidirectional Mendelian randomization study

OBJECTIVES

Previous observational studies have indicated correlations between various inflammatory cytokines and functional outcomes following ischemic stroke (IS); however, the causality remains unclear. We aimed to further evaluate the causal association between 41 circulating inflammatory cytokines and functional outcomes following IS.

METHODS

Two-sample bidirectional Mendelian randomization (MR) analysis was used in this study. The genetic variation of 41 circulating inflammatory cytokines were derived from genome-wide association study (GWAS) data of European ancestry (n = 8293). The corresponding genetic association of functional outcomes following IS were derived from European ancestry GWAS data (n = 6021).

RESULTS

Inverse variance weighted (IVW) analysis showed that genetically predicted increased levels of regulation and activation in normal T-cell expression and secretion factor (RANTES/CCL5) and eosinophilic chemotactic factor (EOTAXIN/CCL11) were positively correlated with the increased adverse functional outcomes (modified Rankin Scale [mRS≥3] following IS (OR: 1.40, 95% CI: 1.002-1.96, p = 0.049; OR: 1.33, 95% CI: 1.15-1.54, p = 0.0001). Interleukin 18 (IL-18) level might be the downstream consequence of adverse functional outcomes following IS (β: -0.09, p = 0.039). Other inflammatory cytokines and functional outcomes following IS did not appear to be causally related.

CONCLUSIONS

This study suggests a causality between inflammation and adverse functional outcomes following IS. RANTES (CCL5) and EOTAXIN (CCL11) may be the upstream factors of adverse functional outcomes following IS, while IL-18 may be the downstream effect of adverse functional outcomes following IS. Whether these cytokines can be used to predict or improve adverse functional outcomes after IS requires further researches.

Global and endothelial G-protein coupled receptor 75 (GPR75) knockout relaxes pulmonary artery and mitigates hypoxia-induced pulmonary hypertension

RATIONALE

Pulmonary hypertension (PH) is a multifactorial disease with a poor prognosis and inadequate treatment options. We found two-fold higher expression of the orphan G-Protein Coupled Receptor 75 (GPR75) in leukocytes and pulmonary arterial smooth muscle cells from idiopathic PH patients and from lungs of C57BL/6 mice exposed to hypoxia. We therefore postulated that GPR75 signaling is critical to the pathogenesis of PH.

METHODS

To test this hypothesis, we exposed global (Gpr75-/-) and endothelial cell (EC) GPR75 knockout (EC-Gpr75-/-) mice and wild-type (control) mice to hypoxia (10% oxygen) or normal atmospheric oxygen for 5 weeks. We then recorded echocardiograms and performed right heart catheterizations.

RESULTS

Chronic hypoxia increased right ventricular systolic and diastolic pressures in wild-type mice but not Gpr75-/- or EC-Gpr75-/- mice. In situ hybridization and qPCR results revealed that Gpr75 expression was increased in the alveoli, airways and pulmonary arteries of mice exposed to hypoxia. In addition, levels of chemokine (CC motif) ligand 5 (CCL5), a low affinity ligand of GPR75, were increased in the lungs of wild-type, but not Gpr75-/-, mice exposed to hypoxia, and CCL5 enhanced hypoxia-induced contraction of intra-lobar pulmonary arteries in a GPR75-dependent manner. Gpr75 knockout also increased pulmonary cAMP levels and decreased contraction of intra-lobar pulmonary arteries evoked by endothelin-1 or U46619 in cAMP-protein kinase A-dependent manner.

CONCLUSION

These results suggest GPR75 has a significant role in the development of hypoxia-induced PH.

BATF2 enhances proinflammatory cytokine responses in macrophages and improves early host defense against pulmonary Klebsiella pneumoniae infection

Basic leucine zipper transcription factor ATF-like 2 (BATF2) is a transcription factor that is emerging as an important regulator of the innate immune system. BATF2 is among the top upregulated genes in human alveolar macrophages treated with LPS, but the signaling pathways that induce BATF2 expression in response to Gram-negative stimuli are incompletely understood. In addition, the role of BATF2 in the host response to pulmonary infection with a Gram-negative pathogen like Klebsiella pneumoniae (Kp) is not known. We show that induction of Batf2 gene expression in macrophages in response to Kp in vitro requires TRIF and type I interferon (IFN) signaling, but not MyD88 signaling. Analysis of the impact of BATF2 deficiency on macrophage effector functions in vitro showed that BATF2 does not directly impact macrophage phagocytic uptake and intracellular killing of Kp. However, BATF2 markedly enhanced macrophage proinflammatory gene expression and Kp-induced cytokine responses. In vivo, Batf2 gene expression was elevated in lung tissue of wild-type (WT) mice 24 h after pulmonary Kp infection, and Kp-infected BATF2-deficient (Batf2-/-) mice displayed an increase in bacterial burden in the lung, spleen, and liver compared with WT mice. WT and Batf2-/- mice showed similar recruitment of leukocytes following infection, but in line with in vitro observations, proinflammatory cytokine levels in the alveolar space were reduced in Batf2-/- mice. Altogether, these results suggest that BATF2 enhances proinflammatory cytokine responses in macrophages in response to Kp and contributes to the early host defense against pulmonary Kp infection.NEW & NOTEWORTHY This study investigates the signaling pathways that mediate induction of BATF2 expression downstream of TLR4 and also the impact of BATF2 on the host defense against pulmonary Kp infection. We demonstrate that Kp-induced upregulation of BATF2 in macrophages requires TRIF and type I IFN signaling. We also show that BATF2 enhances Kp-induced macrophage cytokine responses and that BATF2 contributes to the early host defense against pulmonary Kp infection.

Platelet Derivatives and the Immunomodulation of Wound Healing

Besides their primary role in hemostasis, platelets contain a plethora of immunomodulatory molecules that profoundly affect the entire process of wound repair. Therefore, platelet derivatives, such as platelet-rich plasma or platelet lysate, have been widely employed with promising results in the treatment of chronic wounds. Platelet derivatives provide growth factors, cytokines, and chemokines targeting resident and immigrated cells belonging to the innate and adaptive immune system. The recruitment and activation of neutrophils and macrophages is critical for pathogen clearance in the early phase of wound repair. The inflammatory response begins with the release of cytokines, such as TGF-β, aimed at damping excessive inflammation and promoting the regenerative phase of wound healing. Dysregulation of the immune system during the wound healing process leads to persistent inflammation and delayed healing, which ultimately result in chronic wound. In this review, we summarize the role of the different immune cells involved in wound healing, particularly emphasizing the function of platelet and platelet derivatives in orchestrating the immunological response.

Cell Trafficking at the Intersection of the Tumor-Immune Compartments

Migration is an essential cellular process that regulates human organ development and homeostasis as well as disease initiation and progression. In cancer, immune and tumor cell migration is strongly associated with immune cell infiltration, immune escape, and tumor cell metastasis, which ultimately account for more than 90% of cancer deaths. The biophysics and molecular regulation of the migration of cancer and immune cells have been extensively studied separately. However, accumulating evidence indicates that, in the tumor microenvironment, the motilities of immune and cancer cells are highly interdependent via secreted factors such as cytokines and chemokines. Tumor and immune cells constantly express these soluble factors, which produce a tightly intertwined regulatory network for these cells' respective migration. A mechanistic understanding of the reciprocal regulation of soluble factor-mediated cell migration can provide critical information for the development of new biomarkers of tumor progression and of tumor response to immuno-oncological treatments. We review the biophysical andbiomolecular basis for the migration of immune and tumor cells and their associated reciprocal regulatory network. We also describe ongoing attempts to translate this knowledge into the clinic.

Inflammation after spinal cord injury: a review of the critical timeline of signaling cues and cellular infiltration

Traumatic spinal cord injury (SCI) is a devastating neurological condition that results in a loss of motor and sensory function. Although extensive research to develop treatments for SCI has been performed, to date, none of these treatments have produced a meaningful amount of functional recovery after injury. The primary injury is caused by the initial trauma to the spinal cord and results in ischemia, oxidative damage, edema, and glutamate excitotoxicity. This process initiates a secondary injury cascade, which starts just a few hours post-injury and may continue for more than 6 months, leading to additional cell death and spinal cord damage. Inflammation after SCI is complex and driven by a diverse set of cells and signaling molecules. In this review, we utilize an extensive literature survey to develop the timeline of local immune cell and cytokine behavior after SCI in rodent models. We discuss the precise functional roles of several key cytokines and their effects on a variety of cell types involved in the secondary injury cascade. Furthermore, variations in the inflammatory response between rats and mice are highlighted. Since current SCI treatment options do not successfully initiate functional recovery or axonal regeneration, identifying the specific mechanisms attributed to secondary injury is critical. With a more thorough understanding of the complex SCI pathophysiology, effective therapeutic targets with realistic timelines for intervention may be established to successfully attenuate secondary damage.

Role of P-gp and HDAC2 and their Reciprocal Relationship in Uncontrolled Asthma

INTRODUCTION

Resistance to corticosteroid is an essential mechanism in uncontrolled asthma as the corticosteroid is the mainstay of therapy. There are recent reports that epigenetic factors play a crucial role in the regulation of steroid action. Overexpression of P glycoprotein (P-gp) and reduced expression of Histone Deacetylase 2 (HDAC2) have been linked to regulating the steroid action in other diseases like Nephrotic Syndrome (NS). However, their role in uncontrolled asthma is still not clear and warrants further investigation. We evaluated the expression and activity of P-gp and HDAC2 in patients with Controlled Asthma (CA) and Uncontrolled Asthma (UA).

METHODS

A total of 60 CA (mean age 51.72±17.02 years, male=38), and 38 of UA (mean age=53.55±11.90 years, male=17) were recruited. The level of control was defined according to (Global Initiative for Asthma) GINA 2016 criteria. The mRNA expression of HDAC2 and P-gp was studied by quantitative real-time Polymerase Chain Reaction (PCR), the functional activity of P-gp was evaluated by a commercially available kit via flow cytometry, and HDAC2 enzymatic activity was measured by commercially available kit by Enzyme-Linked Immunosorbent Assay (ELISA).

RESULTS

P-gp expression and the functionality were significantly higher in the UA group of patients as compared to the CA group of patients (p<0.005), moreover HDAC2 expression was significantly reduced in UA patients as compared to CA patients, (p<0.005). The enzymatic activity of HDAC2 was also significantly reduced in UA patients as compared to CA patients (p<0.005).

CONCLUSION

P-gp overexpression and HDAC2 under expression play an essential role in uncontrolled asthma by impairing the response to corticosteroid.

Disruption of CCR5 signaling to treat COVID-19-associated cytokine storm: Case series of four critically ill patients treated with leronlimab

Coronavirus disease 2019 (COVID-19) is associated with considerable morbidity and mortality. The number of confirmed cases of infection with SARS-CoV-2, the virus causing COVID-19 continues to escalate with over 70 million confirmed cases and over 1.6 million confirmed deaths. Severe-to-critical COVID-19 is associated with a dysregulated host immune response to the virus, which is thought to lead to pathogenic immune dysregulation and end-organ damage. Presently few effective treatment options are available to treat COVID-19. Leronlimab is a humanized IgG4, kappa monoclonal antibody that blocks C–C chemokine receptor type 5 (CCR5). It has been shown that in patients with severe COVID-19 treatment with leronlimab reduces elevated plasma IL-6 and chemokine ligand 5 (CCL5), and normalized CD4/CD8 ratios. We administered leronlimab to 4 critically ill COVID-19 patients in intensive care. All 4 of these patients improved clinically as measured by vasopressor support, and discontinuation of hemodialysis and mechanical ventilation. Following administration of leronlimab there was a statistically significant decrease in IL-6 observed in patient A (p=0.034) from day 0–7 and patient D (p=0.027) from day 0–14. This corresponds to restoration of the immune function as measured by CD4+/CD8+ T cell ratio. Although two of the patients went on to survive the other two subsequently died of surgical complications after an initial recovery from SARS-CoV-2 infection.

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Leronlimab is a monoclonal antibody in clinical trials to treat the cytokine storm.

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Critically ill patients received leronlimab through compassionate use and had remarkable recoveries measured objectively.

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The CCR5 receptor is important in recruiting inflammatory cells mainly T cells and macrophages.

•

Leronlimab disrupted this signal and may have been responsible for restoration of the immune system, improved survival and decrease in IL-6.

Chemokine Signatures of Pathogen-Specific T Cells I: Effector T Cells

The choreography of complex immune responses, including the priming, differentiation, and modulation of specific effector T cell populations generated in the immediate wake of an acute pathogen challenge, is in part controlled by chemokines, a large family of mostly secreted molecules involved in chemotaxis and other patho/physiological processes. T cells are both responsive to various chemokine cues and a relevant source for certain chemokines themselves; yet, the actual range, regulation, and role of effector T cell-derived chemokines remains incompletely understood. In this study, using different in vivo mouse models of viral and bacterial infection as well as protective vaccination, we have defined the entire spectrum of chemokines produced by pathogen-specific CD8⁺ and CD4⁺T effector cells and delineated several unique properties pertaining to the temporospatial organization of chemokine expression patterns, synthesis and secretion kinetics, and cooperative regulation. Collectively, our results position the "T cell chemokine response" as a notably prominent, largely invariant, yet distinctive force at the forefront of pathogen-specific effector T cell activities and establish novel practical and conceptual approaches that may serve as a foundation for future investigations into the role of T cell-produced chemokines in infectious and other diseases.

N-terminal Backbone Pairing Shifts in CCL5-12AAA14 Dimer Interface: Structural Significance of the FAY Sequence

CC-type chemokine ligand 5 (CCL5) has been known to regulate immune responses by mediating the chemotaxis of leukocytes. Depending on the environment, CCL5 forms different orders of oligomers to interact with targets and create functional diversity. A recent CCL5 trimer structure revealed that the N-terminal conversed F12-A13-Y14 (¹²FAY¹⁴) sequence is involved in CCL5 aggregation. The CCL5-¹²AAA¹⁴ mutant with two mutations had a deficiency in the formation of high-order oligomers. In the study, we clarify the respective roles of F12 and Y14 through NMR analysis and structural determination of the CCL5-¹²AAA¹⁴ mutant where F12 is involved in the dimer assembly and Y14 is involved in aggregation. The CCL5-¹²AAA¹⁴ structure contains a unique dimer packing. The backbone pairing shifts for one-residue in the N-terminal interface, when compared to the native CCL5 dimer. This difference creates a new structural orientation and leads to the conclusion that F12 confines the native CCL5 dimer configuration. Without F12 anchoring in the position, the interfacial backbone pairing is permitted to slide. Structural plasticity occurs in the N-terminal interaction. This is the first case to report this structural rearrangement through mutagenesis. The study provides a new idea for chemokine engineering and complements the understanding of CCL5 oligomerization and the role of the ¹²FAY¹⁴ sequence.

Integrative Model to Coordinate the Oligomerization and Aggregation Mechanisms of CCL5

CC-type chemokine ligand 5 (CCL5) is involved in the pathogenesis of many inflammatory conditions. Under physiological conditions, CCL5 oligomerization and aggregation are considered to be responsible for its inflammatory properties. The structural basis of CCL5 oligomerization remains controversial because the current oligomer models contain no consensus interactions. In this study, NMR and biophysical analyses proposed evidence that the CC-type CCL5 dimer acts as the basic unit to constitute the oligomer and that CCL5 oligomerizes alternatively through E66-K25 and E66-R44/K45 interactions. In addition, a newly determined trimer structure, constituted by CCL5 and the E66S mutant, reported an interfacial interaction through the N-terminal ¹²FAY¹⁴ sequence. The interaction contributes to CCL5 aggregation and precipitation but not to oligomerization. In accordance with the observations, an integrative model explains the CCL5 oligomerization and aggregation mechanism in which CCL5 assembly consists of two types of dimer-dimer interactions and one aggregation mechanism. For full-length CCL5, the molecular accumulation triggers oligomerization through the E66-K25 and E66-R44/K45 interactions, and the ¹²FAY¹⁴ interaction acts as a secondary effect to derive aggregation and precipitation. In contrast, the E66-R44/K45 interaction might dominate in CCL5 N-terminal truncations, and the interaction would lead to the filament-like formation in solution.

Chemokines in breast cancer: Regulating metabolism

Accumulating evidence indicates that chemokine-chemokine receptor interactions invoke biological responses beyond their originally described function of orchestrating leukocyte trafficking. In this review we will extend the findings that chemokines participate actively in the neoplastic process, and consider the contribution of CCL5 activation of CCR5 on breast cancer cells to upregulation of anabolic metabolic events that would support the energy demands of cell replication and proliferation.

New approaches for diagnosis of dry eye disease

We reviewed the literature for different diagnostic approaches for dry eye disease (DED) including the most recent advances, contradictions and promising diagnostic tools and technique. We performed a broad literature search for articles discussing different methods for diagnosis of DED including assessment of tear osmolarity, tear film stability, ocular biomarkers and others. Articles indexed in PubMed and google scholar were included. With the growing cosmetic industry, environmental pollution, and booming of digital screens, DED is becoming more prevalent. Its multifactorial etiology renders the diagnosis challenging and invites the emergence of new diagnostic tools and tests. Diagnostic tools can be classified, based on the parameter they measure, into tear film osmolarity, functional visual acuity, tear volume, tear turnover, tear film stability, tear film composition, ocular biomarkers and others. Although numerous methods exist, the most accurate diagnosis can be reached through combining the results of more than one test. Many reported tests have shown potential as diagnostic/screening tools, however, require more research to prove their diagnostic power, alone or in combination. Future research should focus on identifying and measuring parameters that are the most specific to DED diagnosis.

Investigation of candidate molecular biomarkers for expression profile analysis of the Gene expression omnibus (GEO) in acute lymphocytic leukemia (ALL)

Much progress has been made in understanding the mechanism of acute lymphocytic leukemia (ALL). However, for adult ALL, there is still a lack of an effective treatment. In the present study, we first used the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) between ALL cell lines and Hodgkin and non-Hodgkin cell lines. Then, the GEO database was also used to detect the DEGs in acute lymphoblastic leukemia (Reh) cells transfected with a normal control or a constitutively active variant of the IkB kinase β. Finally, we found that three key DEGs (CCL5, FSCN1, and HS3ST1) are involved in proliferation and apoptosis according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes Genomes (KEGG) pathway analyses. Finally, we determined that all three target genes that participate in proliferation and apoptosis are regulated via the NF-kB signaling pathway.

Peripheral inflammatory markers and clinical correlations in patients with frontotemporal lobar degeneration with and without the C9orf72 repeat expansion

In this study, our aim was to evaluate potential peripheral inflammatory changes in frontotemporal lobar degeneration (FTLD) patients carrying or not the C9orf72 repeat expansion. To this end, levels of several inflammatory markers (MCP-1, RANTES, IL-10, IL-17A, IL-12p, IFN-γ, IL-1β, IL-8, and hs-CRP) and blood cells counts in plasma and/or serum of FTLD patients (N = 98) with or without the C9orf72 repeat expansion were analyzed. In addition, we evaluated whether the analyzed peripheral inflammatory markers correlated with disease progression or distinct clinical phenotypes under the heterogenous FTLD spectrum. Elevated levels of pro-inflammatory RANTES or MCP-1 and decreased levels of anti-inflammatory IL-10 were found to associate with Parkinsonism and a more rapid disease progression, indicated by longitudinal measurements of either MMSE or ADCS-ADL decline. These findings were observed in the total cohort in general, whereas the C9orf72 repeat expansion carriers showed only slight differences in IL-10 and hemoglobin levels compared to non-carriers. Furthermore, these C9orf72 repeat expansion-associated differences were observed mostly in male subjects. The females in general showed elevated levels of several pro-inflammatory markers compared to males regardless of the C9orf72 genotype. Our study suggests that pro-inflammatory changes observed in the early symptomatic phase of FTLD are associated with distinct clinical profiles and a more rapid disease progression, and that the C9orf72 repeat expansion and gender may also affect the inflammatory profile in FTLD.

Significance of RANTES-CCR5 axis and linked downstream immunomodulation in Dengue pathogenesis: A study from Guwahati, India

We aimed to evaluate the significance of the RANTES-CCR5 axis and resulting immunomodulatory status in Dengue pathogenesis involving a Guwahati, India based population where Dengue cases have increased alarmingly. An increased CC-chemokine receptor type 5 (CCR5) messenger RNA expression and CCR5 positive cell count profile was observed in Dengue cases, the highest being in severe cases. CCR5 ligand RANTES expression was significantly decreased in Dengue cases and inversely correlated with Dengue viremia fold change in severe cases. Monocytes are involved in Dengue virus homing and replication. Its levels and activation profile were higher in Dengue cases. A hyper Th1-biased immunomodulatory profile with upregulated tumor necrosis factor-α levels, and downregulated expression of antiviral cytokine interferon-γ and key regulatory Th2 anti-inflammatory cytokine interleukin 10 was observed in severe Dengue cases compared with mild Dengue cases and controls. The results, therefore, suggest the significance of RANTES-CCR5 axis deregulation and resulting altered immunomodulation in Dengue pathogenesis, and holds prognostic and therapeutic significance.

Proximal recolonization by self-renewing microglia re-establishes microglial homeostasis in the adult mouse brain

Microglia are resident immune cells that play critical roles in maintaining the normal physiology of the central nervous system (CNS). Remarkably, microglia have an intrinsic capacity to repopulate themselves after acute ablation. However, the underlying mechanisms that drive such restoration remain elusive. Here, we characterized microglial repopulation both spatially and temporally following removal via treatment with the colony stimulating factor 1 receptor (CSF1R) inhibitor PLX5622. We show that microglia were replenished via self-renewal, with no contribution from nonmicroglial lineages, including Nestin+ progenitors and the circulating myeloid population. Interestingly, spatial analyses with dual-color labeling revealed that newborn microglia recolonized the parenchyma by forming distinctive clusters that maintained stable territorial boundaries over time, indicating the proximal expansive nature of adult microgliogenesis and the stability of microglia tiling. Temporal transcriptome profiling at different repopulation stages revealed that adult newborn microglia gradually regain steady-state maturity from an immature state that is reminiscent of the neonatal stage and follow a series of maturation programs, including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation, interferon immune activation, and apoptosis. Importantly, we show that the restoration of microglial homeostatic density requires NF-κB signaling as well as apoptotic egress of excessive cells. In summary, our study reports key events that take place from microgliogenesis to homeostasis reestablishment.

Effect of alcohol on the interleukin 6-mediated inflammatory response in a new mouse model of acute-on-chronic liver injury

BACKGROUND AND AIMS

ACLF is usually associated with a precipitant in the setting of a chronically damaged liver. We aim to combine a mouse model with a pre-injured liver (Abcb4/Mdr2^-/-) with a recently standardized ethanol feeding model to dissect alcohol-related inflammatory responses in this model.

METHOD

Ten (n = 64) and 15 (n = 64) week old wild-type (WT) C57BL/6 J and Abcb4^-/- knock-out (KO) mice were either fed control (WT/Cont and KO/Cont groups) or liquid ethanol diet (5% v/v) followed by an ethanol binge (4 mg/kg) (WT/EtOH and KO/EtOH groups). Hepatic mRNA levels of IL6, IFN-G, IL-1B, TGFB1, TNF-A, CCL2, HGF, CRP, RANTES, PNPLA3 and COL3A1 were evaluated using the 2^-ΔΔCt method. IL6 and HGF plasma levels were quantified by ELISA.

RESULTS

Older mice in KO/EtOH group displayed higher IL6 expressions compared to KO/Cont, WT/EtOH and WT/Cont groups of the same age, whereas HGF did not differ. Significant over-expression of CCL2 also corresponded to the same group. Males in KO/EtOH group exhibited higher IL6 expression than females. Lipid droplets were observed in about 80% of mice challenged with ethanol. There was a profound downregulation in PNPLA3 and RANTES levels after ethanol exposure. Mean size of the LDs was inversely correlated with hepatic PNPLA3 levels.

CONCLUSION

We propose a novel promising approach to model alcohol-related ACLI. Acute inflammatory IL6-driven response might help transition from a stable chronic state to a progressive liver damage in Abcb4^-/- mice. Repression of PNPLA3 resulted in a notable expansion in size of lipid droplets, indicating lipid remodeling in this model.

The Role of Eosinophils in Bullous Pemphigoid: A Developing Model of Eosinophil Pathogenicity in Mucocutaneous Disease

Bullous pemphigoid (BP) is an autoimmune blistering disease which carries a significant mortality and morbidity. While historically BP has been characterized as an IgG driven disease mediated by anti-BP180 and BP230 IgG autoantibodies, developments in recent years have further elucidated the role of eosinophils and IgE autoantibodies. In fact, eosinophil infiltration and eosinophilic spongiosis are prominent features in BP. Several observations support a pathogenic role of eosinophils in BP: IL-5, eotaxin, and eosinophil-colony stimulating factor are present in blister fluid; eosinophils line the dermo-epidermal junction (DEJ) in the presence of BP serum, metalloprotease-9 is released by eosinophils at the site of blisters; eosinophil degranulation proteins are found on the affected basement membrane zone as well as in serum corresponding with clinical disease; eosinophil extracellular DNA traps directed against the basement membrane zone are present, IL-5 activated eosinophils cause separation of the DEJ in the presence of BP serum; and eosinophils are the necessary cell required to drive anti-BP180 IgE mediated skin blistering. Still, it is likely that eosinophils contribute to the pathogenesis of BP in numerous other ways that have yet to be explored based on the known biology of eosinophils. We herein will review the role of eosinophils in BP and provide a framework for understanding eosinophil pathogenic mechanisms in mucocutaneous disease.

IP-10 and RANTES as biomarkers for pulmonary tuberculosis diagnosis and monitoring

OBJECTIVE

We aimed to determine whether IP-10 and RANTES plasma levels can be used in diagnosis and monitoring of pulmonary tuberculosis (PTB).

METHODS

Plasma levels of cytokines/chemokines were measured using a Bio-Plex^® multiplex cytokine assay system in a cohort containing 457 clinically suspected PTB patients including a training set (n = 41)and two independent test sets A (n = 242) and B (n = 174).

RESULTS

Plasma levels of IP-10 and RANTES were significantly higher in PTB patients than healthy controls' in both training and independent test sets (P < 0.05). Compared with other combinations, the combination of IP-10 and RANTES had the best performance with an AUC of 1.0 in training set. The performance characteristic of this model was successfully validated in independent test set A although this combination only resulted in a slightly improvement of AUC value in independent test set B. Plasma IP-10 and RANTES levels were weakly and positively correlated with blood glucose concentrations. Moreover, IP-10 levels were positively correlated with CRP and ESR in PTB patients. Furthermore, in response to therapy, both IP-10 and RANTES levels significantly decreased over the period of 6 months (P < 0.001).

CONCLUSIONS

Taken together, combination of IP-10 and RANTES could be potentially used as diagnostic and monitoring biomarker in PTB management.

O-GalNAcylation of RANTES Improves Its Properties as a Human Immunodeficiency Virus Type 1 Entry Inhibitor

Many human proteins have the potential to be developed as therapeutic agents. However, side effects caused by direct administration of natural proteins have significantly slowed expansion of protein therapeutics into the clinic. Post-translational modifications (PTMs) can improve protein properties, but because of significant knowledge gaps, we are considerably limited in our ability to apply PTMs to generate better protein therapeutics. Here, we seek to fill the gaps by studying the PTMs of a small representative chemotactic cytokine, RANTES. RANTES can inhibit HIV-1 infection by competing with it for binding to receptor CCR5 and stimulating CCR5 endocytosis. Unfortunately, RANTES can induce strong signaling, leading to severe inflammatory side effects. We apply a chemical biology approach to explore the potential of post-translationally modified RANTES as safe inhibitors of HIV-1 infection. We synthesized and systematically tested a library of RANTES isoforms for their ability to inhibit inflammatory signaling and prevent HIV-1 infection of primary human cells. Through this research, we revealed that most of the glycosylated variants have decreased inflammation-associated properties and identified one particular glyco variant, a truncated RANTES containing a Galβ1-3GalNAc disaccharide α-linked to Ser4, which stands out as having the best overall properties: relatively high HIV-1 inhibition potency but also weak inflammatory properties. Moreover, our results provided a structural basis for the observed changes in the properties of RANTES. Taken together, this work highlights the potential importance of glycosylation as an alternative strategy for developing CCR5 inhibitors to treat HIV-1 infection and, more generally, for reducing or eliminating unwanted properties of therapeutic proteins.

CD4+ T cells in atherosclerosis: Regulation by platelets

Atherosclerosis is an inflammatory and thrombotic disease, in which both CD4+ T cells and platelets play important roles throughout all stages of atherogenesis. CD4+ T cells are the most abundant T cells present in atherosclerotic lesions. They are primarily seen as type 1 T helper (Th1) cells, while the other CD4+ T cell subsets Th2, Th17, and regulatory T (Treg) cells are also found in the lesions with lower frequencies. CD4+ T effector cells release various cytokines, which exert paracrine or autocrine effects among different CD4+ T cell subsets and other lesional cells and subsequently modulate inflammatory processes in the lesions. Platelets are instrumental in thrombosis and haemostasis, but also play important regulatory roles in immune response, inflammation, and angiogenesis. The present review summarises the current knowledge and/or understanding on how platelets regulate recruitment, activation, differentiation, and cytokine production of different CD4+ T cell subsets, as well as impacts of the platelet-CD4+ T cell interactions on atherogenesis. The research perspectives of platelet-CD4+ T cell interaction in atherosclerosis are also discussed.

C-C Chemokine Ligand-5 is critical for facilitating macrophage infiltration in the early phase of liver ischemia/reperfusion injury

CCL5/RANTES, a chemoattractant for myeloid cells, is induced by hepatic ischemia/reperfusion injury (IRI). The roles of CCL5 in hepatic IRI were carried out by means of CCL5 immunodepletion, antagonistic competition by Met-CCL5, and treatment with recombinant murine CCL5 (rmCCL5). Depletion or inhibition of CCL5 reduced severity of hepatic IRI, whereas rmCCL5 treatment aggravated liver IRI as manifested in elevated serum alanine aminotransferase (ALT) and tissue myeloperoxidase (MPO) levels. Moreover, IRI severity was reduced in CCL5-knockout (CCL5-KO) mice versus wildtype (WT) mice, with drops in serum ALT level, intrahepatic MPO activity, and histological pathology. Bone marrow transplantion (BMT) studies show that myeloid cells and tissue cells are both required for CCL5-aggravated hepatic IRI. The profile of liver-infiltrating leukocyte subsets after hepatic reperfusion identified CD11b+ cells as the only compartment significantly reduced in CCL5-KO mice versus WT controls at early reperfusion phase. The role of CCL5 recruiting CD11b+ cells in early reperfusion was validated by in vitro transwell migration assay of murine primary macrophages (broadly characterized by their CD11b expression) in response to liver lysates after early reperfusion. Taken together, our results demonstrate a sequence of early events elicited by CCL5 chemoattracting macrophage that result in inflammatory aggravation of hepatic IRI.

Functional role of CCL5/RANTES for HCC progression during chronic liver disease

BACKGROUND & AIMS

During liver inflammation, triggering fibrogenesis and carcinogenesis immune cells play a pivotal role. In the present study we investigated the role of CCL5 in human and in murine models of chronic liver inflammation leading to hepatocellular carcinoma (HCC) development.

METHODS

CCL5 expression and its receptors were studied in well-defined patients with chronic liver disease (CLD) and in two murine inflammation based HCC models. The role of CCL5 in inflammation, fibrosis, tumor initiation and progression was analyzed in different cell populations of NEMO^Δhepa/CCL5^-/- animals and after bone marrow transplantation (BMT). For therapeutic intervention Evasin-4 was injected for 24h or 8weeks.

RESULTS

In CLD patients, CCL5 and its receptor CCR5 are overexpressed - an observation confirmed in the Mdr2^-/- and NEMO^Δhepa model. CCL5 deletion in NEMO^Δhepa mice diminished hepatocyte apoptosis, compensatory proliferation and fibrogenesis due to reduced immune cell infiltration. Especially, CD45⁺/Ly6G⁺ granulocytes, CD45⁺/CD11b⁺/Gr1.1⁺/F4/80⁺ pro-inflammatory monocytes, CD4⁺ and CD8⁺ T cells were decreased. One year old NEMO^Δhepa/CCL5^-/- mice displayed smaller and less malignant tumors, characterized by reduced proliferative capacity and less pronounced angiogenesis. We identified hematopoietic cells as the main source of CCL5, while CCL5 deficiency did not sensitise NEMO^Δhepa hepatocytes towards TNFα induced apoptosis. Finally, therapeutic intervention with Evasin-4 over a period of 8weeks ameliorated liver disease progression.

CONCLUSION

We identified an important role of CCL5 in human and functionally in mice with disease progression, especially HCC development. A novel approach to inhibit CCL5 in vivo thus appears encouraging for patients with CLD.

LAY SUMMARY

Our present study identifies the essential role of the chemoattractive cytokine CCL5 for liver disease progression and especially hepatocellular carcinoma development in men and mice. Finally, the inhibition of CCL5 appears to be encouraging for therapy of human chronic liver disease.

RANTES levels in peripheral blood, CSF and contused brain tissue as a marker for outcome in traumatic brain injury (TBI) patients

Background

Traumatic brain injury (TBI) causes activation of several neurochemical and physiological cascades, leading to neurological impairment. We aimed to investigate the level of novel chemokine RANTES in plasma, cerebrospinal fluid (CSF) and contused brain tissue in traumatic brain injury patients and to correlate the expression of this chemokine with the severity of head injury and neurological outcome.

Methods

This longitudinal case control study was performed on 70 TBI patients over a period of 30 months. Glasgow coma scale (GCS) and Glasgow outcome score were used to assess the severity of head injury and clinical outcome. Level of RANTES was quantified in plasma (n = 60), CSF (N = 10) and contused brain tissue (n = 5). Alterations in the plasma levels on 1st and 5th day following TBI were assessed. Patients were categorized as severe (GCS < 8) (SHI), moderate and mild Head injury (GCS > 8–14). 15 healthy volunteers were taken as the control group.

Results

The median plasma RANTES levels were 971.3 (88.40–1931.1); 999.2 (31.2–2054.9); 471.8 (370.9–631.9) for SHI, MHI and healthy control respectively and showed statistically significant variation (p = 0.005). There was no statistical difference in the mean 1st and 5th day RANTES levels for the SHI group. However, admission RANTES levels were significantly higher in patients who died than those who survived (p = 0.04). Also, RANTES levels were significantly higher in plasma as compared to contused brain tissue and CSF (p = 0.0001).

Conclusion

This is the first study of its kind which shows that there is significant correlation of admission RANTES levels and early mortality. Another interesting finding was the significant upregulated in the expression of RANTES in plasma, compared to CSF and contused brain tissue following severe TBI.

Exploiting agonist biased signaling of chemokines to target cancer

As knowledge of growth-independent functions of cancer cells is expanding, exploration into the role of chemokines in modulating cancer pathogenesis, particularly metastasis, continues to develop. However, more study into the mechanisms whereby chemokines direct the migration of cancer cells is needed before specific therapies can be generated to target metastasis. Herein, we draw attention to the longstanding conundrum in the field of chemokine biology that chemokines stimulate migration in a biphasic manner; and explore this phenomenon's impact on chemokine function in the context of cancer. Typically, low concentrations of chemokines lead to chemotactic migration and higher concentrations halt migration. The signaling mechanisms that govern this phenomenon remain unclear. Over the last decade, we have defined a novel signaling mechanism for regulation of chemokine migration through ligand oligomerization and biased agonist signaling. We provide insight into this new paradigm for chemokine signaling and discuss how it will impact future exploration into chemokine function and biology. In the pursuit of producing more novel cancer therapies, we suggest a framework for pharmaceutical application of the principles of chemokine oligomerization and biased agonist signaling in cancer. © 2016 Wiley Periodicals, Inc.

Response of immune response genes to adjuvants poly [di(sodium carboxylatoethylphenoxy)phosphazene] (PCEP), CpG oligodeoxynucleotide and emulsigen at intradermal injection site in pigs

Understanding the mechanisms by which adjuvants mediate their effects provide critical information on how innate immunity influences the development of adaptive immunity. Despite being a critical vaccine component, the mechanisms by which adjuvants mediate their effects are not fully understood and this is especially true when they are used in large animals. This lack of understanding limits our ability to design effective vaccines. In the present study, we administered polyphosphazene (PCEP), CpG oligodeoxynucleotides (CpG), emulsigen or saline via an intradermal injection into pigs and assessed the impact on the expression of reported 'adjuvant response genes' over time. CpG induced a strong upregulation of the chemokine CXL10 several 'Interferon Response Genes', as well as TNFα, and IL-10, and a down-regulation of IL-17 genes. Emulsigen upregulated expression of chemokines CCL2 and CCL5, proinflammatory cytokines IL-6 and TNFα, as well as TLR9, and several IFN response genes. PCEP induced the expression of chemokine CCL2 and proinflammatory cytokine IL-6. These results suggest that emulsigen and CpG may promote recruitment of innate immune cells and Th1 type cytokine production but that PCEP may promote a Th-2 type immune response through the induction of IL-6, an inducer of B cell activity and differentiation.

Type I Interferon Induced Epigenetic Regulation of Macrophages Suppresses Innate and Adaptive Immunity in Acute Respiratory Viral Infection

Influenza A virus (IAV) is an airborne pathogen that causes significant morbidity and mortality each year. Macrophages (Mϕ) are the first immune population to encounter IAV virions in the lungs and are required to control infection. In the present study, we explored the mechanism by which cytokine signaling regulates the phenotype and function of Mϕ via epigenetic modification of chromatin. We have found that type I interferon (IFN-I) potently upregulates the lysine methyltransferase Setdb2 in murine and human Mϕ, and in turn Setdb2 regulates Mϕ-mediated immunity in response to IAV. The induction of Setdb2 by IFN-I was significantly impaired upon inhibition of the JAK-STAT signaling cascade, and chromatin immunoprecipitation revealed that both STAT1 and interferon regulatory factor 7 bind upstream of the transcription start site to induce expression. The generation of Setdb2^LacZ reporter mice revealed that IAV infection results in systemic upregulation of Setdb2 in myeloid cells. In the lungs, alveolar Mϕ expressed the highest level of Setdb2, with greater than 70% lacZ positive on day 4 post-infection. Silencing Setdb2 activity in Mϕ in vivo enhanced survival in lethal IAV infection. Enhanced host protection correlated with an amplified antiviral response and less obstruction to the airways. By tri-methylating H3K9, Setdb2 silenced the transcription of Mx1 and Isg15, antiviral effectors that inhibit IAV replication. Accordingly, a reduced viral load in knockout mice on day 8 post-infection was linked to elevated Isg15 and Mx1 transcript in the lungs. In addition, Setdb2 suppressed the expression of a large number of other genes with proinflammatory or immunomodulatory function. This included Ccl2, a chemokine that signals through CCR2 to regulate monocyte recruitment to infectious sites. Consistently, knockout mice produced more CCL2 upon IAV infection and this correlated with a 2-fold increase in the number of inflammatory monocytes and alveolar Mϕ in the lungs. Finally, Setdb2 expression by Mϕ suppressed IL-2, IL-10, and IFN-γ production by CD4⁺ T cells in vitro, as well as proliferation in IAV-infected lungs. Collectively, these findings identify Setdb2 as a novel regulator of the immune system in acute respiratory viral infection.

IAV causes seasonal epidemics that result in significant morbidity and mortality annually. Less frequently, novel viral strains emerge and are responsible for much larger outbreaks around the globe. In the last pandemic in 2009, an estimated 300,000 people died from IAV infection or secondary complications. Since the virus rapidly evolves, a new vaccine must be developed each year. Since vaccine effectiveness can be highly variable, identifying other therapeutic targets is appealing for the treatment of severe disease in high-risk individuals such as young children, the elderly, and immunocompromised individuals. In this study, we found that the protein Setdb2 regulates the immune response to IAV via an epigenetic mechanism in Mϕ. Inhibition of Setdb2 activity was beneficial for host protection due to an amplified antiviral response, which correlated with accelerated viral clearance and less damage to the lungs. Therefore, targeting Setdb2 may be a powerful therapeutic strategy for treating severe pulmonary disease caused by IAV and potentially other viral pathogens that trigger robust IFN-I production.

Primary Human Blood Dendritic Cells for Cancer Immunotherapy-Tailoring the Immune Response by Dendritic Cell Maturation

Dendritic cell (DC)-based cancer vaccines hold the great promise of tipping the balance from tolerance of the tumor to rejection. In the last two decades, we have gained tremendous knowledge about DC-based cancer vaccines. The maturation of DCs has proven indispensable to induce immunogenic T cell responses. We review the insights gained from the development of maturation cocktails in monocyte derived DC-based trials. More recently, we have also gained insights into the functional specialization of primary human blood DC subsets. In peripheral human blood, we can distinguish at least three primary DC subsets, namely CD1c⁺ and CD141⁺ myeloid DCs and plasmacytoid DCs. We reflect the current knowledge on maturation and T helper polarization by these blood DC subsets in the context of DC-based cancer vaccines. The maturation stimulus in combination with the DC subset will determine the type of T cell response that is induced. First trials with these natural DCs underline their excellent in vivo functioning and mark them as promising tools for future vaccination strategies.

Ischemia and reperfusion injury in renal transplantation: hemodynamic and immunological paradigms

Ischemia and reperfusion injury is an inevitable event in renal transplantation. The most important consequences are delayed graft function, longer length of stay, higher hospital costs, high risk of acute rejection, and negative impact of long-term follow-up. Currently, many factors are involved in their pathophysiology and could be classified into two different paradigms for education purposes: hemodynamic and immune. The hemodynamic paradigm is described as the reduction of oxygen delivery due to blood flow interruption, involving many hormone systems, and oxygen-free radicals produced after reperfusion. The immune paradigm has been recently described and involves immune system cells, especially T cells, with a central role in this injury. According to these concepts, new strategies to prevent ischemia and reperfusion injury have been studied, particularly the more physiological forms of storing the kidney, such as the pump machine and the use of antilymphocyte antibody therapy before reperfusion. Pump machine perfusion reduces delayed graft function prevalence and length of stay at hospital, and increases long-term graft survival. The use of antilymphocyte antibody therapy before reperfusion, such as Thymoglobulin™, can reduce the prevalence of delayed graft function and chronic graft dysfunction.

Molecular and functional roles of 6C CC chemokine 19 in defense system of striped murrel Channa striatus

In this study, we have reported the molecular information of chemokine-19 (Chem19) from striped murrel Channa striatus (Cs). CsCC-Chem19 cDNA sequence was 555 base pair (bp) in length which is 68bp 5' untranslated region (UTR), 339bp translated region and 149bp 3' UTR. The translated region is encoded for a polypeptide of 112 amino acids. CsCC-Chem19 peptide contains a signal sequence between 1 and 26 and an interleukin (IL) 8 like domain between 24 and 89. The multiple sequence alignment showed a 'DCCL' motif, an indispensable motif present in all CC chemokines which was conserved throughout the evolution. Phylogenetic tree showed that CsCC-Chem19 formed a cluster with chemokine 19 from fishes. Secondary structure of CsCC-Chem19 revealed that the peptide contains maximum amount of coils (61.6%) compared to α-helices (25.9%%) and β-sheet (12.5%). Further, 3D analysis indicated that the cysteine residues at 33, 34, 59 and 75 making the disulfide bridges as 33 = 59 and 34 = 75. Significantly (P < 0.05) highest CsCC-Chem19 mRNA expression was observed in blood and it was up-regulated upon fungus and bacterial infection. Utilizing the coding region of CsCC-Chem19, recombinant CsCC-Chem19 protein was produced. The recombinant CsCC-Chem19 protein induced the cellular proliferation and respiratory burst activity of C. striatus peripheral blood leukocytes (PBL) in a concentration dependent manner. Moreover, the chemotactic activity showed that the recombinant CsCC-Chem19 significantly (P < 0.05) enhanced the movement of PBL of C. striatus. Conclusively, CsCC-Chem19 is a 6C CC chemokine having an ability to perform both inflammatory and homeostatic functions. However, further research is necessary to understand the potential of 6C CC chemokine 19 of C. striatus, particularly their regulatory ability on different cellular components in the defense system.

Different maturation cocktails provide dendritic cells with different chemoattractive properties

Background

Dendritic cells (DC) are currently implemented as immunotherapeutic strategy for the treatment of tumor patients based on their central role in the immune system. Despite good results were obtained in vitro and in animal models, their clinical use has provided limited success suggesting the requirement to optimise the protocol for their production.

Methods

A cDNA array was performed on FastDC obtained from the differentiation of human peripheral blood monocytes stimulated with the clinical gold standard or with two alternative maturation cocktails combining interferon (IFN)γ and ligands for different toll like receptors (TLR).

Results

A stronger modulation of the DC transcriptome with respect to immature DC was found in alternatively stimulated DC when compared to DC stimulated with the clinical gold standard. A major class of molecules differentially expressed using distinct DC stimulation protocols were chemokines. Validation of their differential expression pattern at the mRNA and protein level confirmed the secretion of inflammatory chemokines by the alternative DC. Functional analyses of the chemotactic properties of DC “wash out” supernatants highlighted the ability of alternative, but not of gold standard DC to efficiently recruit immune cells with a prevalence of monocytes. Effector cells belonging to the innate as well as adaptive immunity were also attracted and the interaction with alternative DC resulted in enhanced secretion of IFNγ and induction of cytotoxic activity. Using leukocytes from cancer patients, it was demonstrated that the monocyte-attracting activity targeted cells with an inflammatory phenotype characterised by high levels of HLA-DR expression.

Conclusions

Despite other classes of immune modulatory genes differently expressed in the alternative DC require to be investigated and characterised regarding their functional consequences, the reduced maturation state and chemoattractive properties of the gold standard versus alternative DC clearly promote the necessity to change the clinically used maturation cocktail of DC in order to improve the outcome of patients treated with DC-based vaccines.

Different locations of RANTES and its receptors on mouse epididymal spermatozoa

Our previous study showed that the chemokine regulated upon activation normal T-cell expressed and secreted (RANTES) originating from the mouse epididymis bound to the midpiece of luminal spermatozoa. The present study was undertaken to investigate the association between RANTES and epididymal spermatozoa and to determine whether the association is mediated by the RANTES receptors CCR1, CCR3 or CCR5. The use of reverse transcription polymerase chain reaction (RT-PCR), immunohistochemical staining and immunofluorescent staining demonstrated that RANTES secreted by apical and narrow cells of mouse epididymal ducts was associated with luminal spermatozoa. Flow cytometric analysis and immunofluorescent labelling revealed that the association between RANTES and spermatozoa of different regions weakened gradually as the spermatozoa moved along the epididymis. Moreover, CCR1, CCR3 and CCR5 were expressed in epididymal spermatozoa and located on the head of epididymal spermatozoa, while RANTES was generally located at the midpiece. In conclusion, RANTES and its receptors were not in the same sperm location, suggesting that RANTES binding to mouse epididymal spermatozoa is independent of CCR1, CCR3 and CCR5.

Charge-selective fractions of naturally occurring nanoparticles as bioactive nanocarriers for cancer therapy

A carnivorous fungus, Arthrobotrys oligospora, has been shown to secrete nanoparticles. In the present work, the potential of two charge-selective fractions of fungal nanoparticles (FNPs) as bioactive nanocarriers in cancer therapy is explored by investigating their immunostimulatory activities, cytotoxic mechanisms and in vitro immunochemotherapeutic effects. A surface charge-selective fractionation procedure to purify crude FNPs has been established, and two FNP fractions (i.e. FNP1 and FNP2), with different surface charges and similarly reduced diameters of 100-200nm, are obtained. Both FNP fractions enhance the secretion of multiple proinflammatory cytokines and chemokines from macrophages and splenocytes. However, FNP2 has stronger cytotoxicity than FNP1. It is FNP2 not FNP1 that could clearly inhibit cell proliferation by inducing apoptosis and arresting cells at the sub G0/G1 phase. Both the FNP fractions can form pH-responsive nanocomplexes with doxorubicin (DOX) via electrostatic interactions. For direct cytotoxicity, DOX-FNP2 complexes demonstrate higher activity than DOX against multiple tumor cells, while DOX-FNP1 complexes show weaker activity than DOX. Interestingly, in a co-culture experiment where splenocytes are co-cultured with tumor cells, both DOX-FNP complexes demonstrate higher cytotoxicity than DOX. In conclusion, this work proposes a combined therapeutics for cancer treatment using charge-selective fractions of FNPs as bioactive nanocarriers.

Hydroxytyrosol inhibits chemokine C-C motif ligand 5 mediated aged quiescent fibroblast-induced stimulation of breast cancer cell proliferation

Cancer is an age-associated disease. Although the mechanisms of age-associated increase in cancer incidence are not completely understood, it is believed that the tumor stromal environment significantly influences epithelial malignancy. Fibroblasts are a major cell type in the stroma and, under normal conditions, fibroblasts reside in the quiescent state. Cellular quiescence is a reversible process where cells enter into the proliferative cycle and then exit back to quiescence. We have shown previously that quiescent fibroblasts lose their proliferative capacity as they age, and we defined this mode of cellular aging as chronological life span. Using conditioned media and co-culture experiments, results from this study show that normal human fibroblasts (NHFs) nearing the end of their chronological life span stimulate the proliferation of MB231 and MCF7 human breast epithelial cancer cells. Chemokine C-C motif ligand 5 (CCL5) expression was found to be approximately 8-fold higher in old compared to that in young quiescent NHFs, which correlated with an increase in the ERK1/2-cyclin D1 pro-proliferative pathway in MB231 cells. Conditioned media treated with anti-CCL5 antibody suppressed the activation of the ERK1/2-cyclin D1 pathway and proliferation of MB231 cells. Hydroxytyrosol, a dietary polyphenol and an active ingredient of olive, inhibited CCL5 expression in aging quiescent NHFs. This inhibition was associated with NHFs inability to activate the ERK1/2-cyclin D1 pathway and enhance proliferation of MB231 cells. These results show that fibroblasts nearing the end of their chronological life span promote proliferation of human breast epithelial cancer cells and dietary polyphenols inhibit this process.

Characterization of structure, dynamics, and detergent interactions of the anti-HIV chemokine variant 5P12-RANTES

RANTES (CCL5) is a chemokine that recruits immune cells to inflammatory sites by interacting with the G-protein coupled receptor CCR5, which is also the primary coreceptor used together with CD4 by HIV to enter and infect target cells. Ligands of CCR5, including chemokines and chemokine analogs, are capable of blocking HIV entry, and studies of their structures and interactions with CCR5 will be key to understanding and optimizing HIV inhibition. The RANTES derivative 5P12-RANTES is a highly potent HIV entry inhibitor that is being developed as a topical HIV prevention agent (microbicide). We have characterized the structure and dynamics of 5P12-RANTES by solution NMR. With the exception of the nine flexible N-terminal residues, 5P12-RANTES has the same structure as wild-type RANTES but unlike the wild-type, does not dimerize via its N-terminus. To prepare the ground for interaction studies with detergent-solubilized CCR5, we have also investigated the interaction of RANTES and 5P12-RANTES with various commonly used detergents. Both RANTES variants are stable in Cymal-5, DHPC, Anzergent-3-12, dodecyltrimethylammonium chloride, and a DDM/CHAPS/CHS mixture. Fos-Cholines, dodecyldimethylglycine, and sodium dodecyl-sulfate denature both RANTES variants at low pH, whereas at neutral pH the stability is considerably higher. The onset of Fos-Choline-12-induced denaturation and the denatured state were characterized by circular dichroism and NMR. The detergent interaction starts below the critical micelle concentration at a well-defined mixed hydrophobic/positive surface region of the chemokine, which overlaps with the dimer interface. An increase of Fos-Choline-12 concentration above the critical micelle concentration causes a transition to a denatured state with a high α-helical content.

A meta-analysis of the association between the CC chemokine ligand 5 (CCL5) -403 G>A gene polymorphism and tuberculosis susceptibility

Aim

Many case-control studies have been performed in the recent past to investigate the association between CCL5 -403 G>A (rs2107538) gene polymorphism and tuberculosis (TB) susceptibility in various ethnic groups. However, these studies have produced inconsistent and contradictory results. In the present study, meta-analysis was performed to assess the association between CCL5 -403 G>A polymorphism and TB risk.

Methodology

Quantitative synthesis was done for the published studies based upon association between CCL5 -403 G>A polymorphism and TB risk from PubMed (Medline), EMBASE web search. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for allele contrast, homozygous, heterozygous, dominant and recessive genetic models.

Results

A total of six studies comprising 1638 confirmed TB cases and 1519 healthy controls were included in this meta-analysis. Variant A allele (A vs. G: p = 0.035; OR = 1.301, 95% CI = 1.019 to 1.662) and variant homozygous (AA vs. GG; p = 0.001; OR = 1.520, 95% CI = 1.202 to 1.923) carriers were significantly associated with TB susceptibility. Similarly, recessive model (AA vs. GG+GA: p = 0.016; OR = 1.791, 95% CI = 1.117 to 2.873) also indicated increased TB risk. Whereas, heterozygous (GA vs. GG: p = 0.837; OR = 1.028, 95% CI = 0.791 to 1.335) and dominant (AA+GA vs. GG: p = 0.222; OR = 1.188, 95% CI = 0.901 to 1.567) models failed to show increased risk of developing TB.

Conclusions

This meta-analysis suggests that there is a significant association between the CCL5 -403 G>A polymorphism and increased risk of TB. However, larger well-designed epidemiological studies with stratified case control and biological characterization may be helpful to validate this association.

Association between specific adipose tissue CD4+ T-cell populations and insulin resistance in obese individuals

BACKGROUND & AIMS

An increased number of macrophages in adipose tissue is associated with insulin resistance and metabolic dysfunction in obese people. However, little is known about other immune cells in adipose tissue from obese people, and whether they contribute to insulin resistance. We investigated the characteristics of T cells in adipose tissue from metabolically abnormal insulin-resistant obese (MAO) subjects, metabolically normal insulin-sensitive obese (MNO) subjects, and lean subjects. Insulin sensitivity was determined by using the hyperinsulinemic euglycemic clamp procedure.

METHODS

We assessed plasma cytokine concentrations and subcutaneous adipose tissue CD4(+) T-cell populations in 9 lean, 12 MNO, and 13 MAO subjects. Skeletal muscle and liver samples were collected from 19 additional obese patients undergoing bariatric surgery to determine the presence of selected cytokine receptors.

RESULTS

Adipose tissue from MAO subjects had 3- to 10-fold increases in numbers of CD4(+) T cells that produce interleukin (IL)-22 and IL-17 (a T-helper [Th] 17 and Th22 phenotype) compared with MNO and lean subjects. MAO subjects also had increased plasma concentrations of IL-22 and IL-6. Receptors for IL-17 and IL-22 were expressed in human liver and skeletal muscle samples. IL-17 and IL-22 inhibited uptake of glucose in skeletal muscle isolated from rats and reduced insulin sensitivity in cultured human hepatocytes.

CONCLUSIONS

Adipose tissue from MAO individuals contains increased numbers of Th17 and Th22 cells, which produce cytokines that cause metabolic dysfunction in liver and muscle in vitro. Additional studies are needed to determine whether these alterations in adipose tissue T cells contribute to the pathogenesis of insulin resistance in obese people.

Home sweet home: the tumor microenvironment as a haven for regulatory T cells

CD4⁺Foxp3⁺ regulatory T cells (T_regs) have a fundamental role in maintaining immune balance by preventing autoreactivity and immune-mediated pathology. However this role of T_regs extends to suppression of anti-tumor immune responses and remains a major obstacle in the development of anti-cancer vaccines and immunotherapies. This feature of T_reg activity is exacerbated by the discovery that T_reg frequencies are not only elevated in the blood of cancer patients, but are also significantly enriched within tumors in comparison to other sites. These observations have sparked off the quest to understand the processes through which T_regs become elevated in cancer-bearing hosts and to identify the specific mechanisms leading to their accumulation within the tumor microenvironment. This manuscript reviews the evidence for specific mechanisms of intra-tumoral T_reg enrichment and will discuss how this information may be utilized for the purpose of manipulating the balance of tumor-infiltrating T cells in favor of anti-tumor effector cells.

SLC gene-modified dendritic cells mediate T cell-dependent anti-gastric cancer immune responses in vitro

Dendritic cells (DCs) are potent professional antigen-presenting cells (APCs) with the ability to prime naïve T cells, and play an important role in the initiation and regulation of immune responses. In this study, we constructed a recombinant adenovirus carrying the SLC gene (Ad-SLC), and detected the biological effects of Ad-SLC-modified DCs as an adjuvant for the initiation of gastric cancer immune responses. Human DCs were transfected with Ad-SLC and the recombinant adenovirus carrying the β-galactosidase gene, Ad-LacZ, respectively. Modified DCs were pulsed with the cell lysate antigen of SGC-7901 cells (a type of gastric cancer cell line) and co-cultured with autologous T cells. The T cells were harvested and incubated with SGC-7901 cells and the cytotoxic function of the T cells was detected. Based on the data, the expression of mature DC phenotypes CD83 and CCR7 was upregulated after transfection with Ad-SLC and the chemotaxis function of DCs was augmented after transfection with Ad-SLC. Moreover, the expression of RANTES in DCs was upregulated by Ad-SLC transfection, while expression levels of IL-12p70 and IL-10 were not significantly altered. When co-cultured with autologous T cells, DCs modified with the SLC gene and pulsed with SGC-7901 cell lysates significantly promoted the proliferation of autologous T cells and induced Th1 differentiation, and displayed a strong cytotoxicity to SGC-7901 cells. In conclusion, Ad-SLC promoted DC maturation, enhancing the ability of DCs for T-cell chemotaxis and T-cell stimulation, and induced specific anti-gastric cancer cellular immunity. Recombinant Ad-SLC-modified DCs may be used as an adjuvant to induce an effective anti-gastric cancer immune response.

Human blood mDC subsets exhibit distinct TLR repertoire and responsiveness

Human blood DCs encompass pDCs and two subsets of mDCs: CD1c(+) mDCs and CD141(+) mDCs. The rare CD141(+) DC population is thought to be the equivalent of mouse CD8α(+) cDCs that play a significant role in antigen cross-presentation. Here, we analyzed by Q-PCR TLR1-10 expression in blood DC subsets. Whereas CD1c(+) DCs express all TLR except TLR9, CD141(+) DCs present a more restricted pattern with high expression of TLR3 and -10, expression of TLR1,-2, -6, and -8, and lack of TLR4, -5, -7, and -9. The in vitro analysis of isolated mDC subset reponsiveness to an extensive panel of TLR ligands confirmed these results, with CD141(+) DCs responding only to TLR1/2, -3, and -7/8. The cytokine/chemokine production profile of isolated CD141(+) DCs was also more restricted, as they produced mainly proinflammatory cytokines but no IL-12 and to a lower level, in comparison with CD1c(+) DCs, except for CXCL10, CCL5, and IFN-β. In contrast, with the use of a whole blood assay, we found that CD141(+) DCs produce IL-12 in response to TLR1/2, -3, and more surprisingly, -9. Finally, both mDC subsets are potent inducers of Th1 response, particularly after TLR3 triggering. Taken together, these data confirmed functional differences between blood mDC subsets. The major response of CD141(+) mDCs to TLR3 ligand and their cytokine production pattern suggest a role for these cells in antiviral immunity.

Systemic immune activation shapes stroke outcome

Stroke is a major cause of morbidity and mortality, and activation of the immune system can impact on stroke outcome. Although the majority of research has focused on the role of the immune system after stroke there is increasing evidence to suggest that inflammation and immune activation prior to brain injury can influence stroke risk and outcome. With the high prevalence of co-morbidities in the Western world such as obesity, hypertension and diabetes, pre-existing chronic 'low-grade' systemic inflammation has become a customary characteristic of stroke pathophysiology that needs to be considered in the search for new therapies. The importance of the immune system in stroke has been demonstrated in a number of ways, both experimentally and in the clinical setting. This review will focus on the effect of immune activation arising from systemic inflammatory conditions and infection, how it affects the incidence and outcomes of stroke, and the possible underlying mechanisms involved. This article is part of a Special Issue entitled 'Neuroinflammation in neurodegeneration and neurodysfunction'.

RANTES, MCP-1 chemokines and factors describing rheumatoid arthritis

The MCP-1/CCL2 as well as RANTES/CCL5 chemokines are potent chemoattractants involved in immunoregulatory and inflammatory processes of rheumatoid arthritis. Recent studies demonstrated elevated levels of MCP-1 and RANTES in plasma, synovial fluid, and the synovial tissue of patients with RA. To examine the relationship among MCP-1 and RANTES single nucleotide polymorphisms and circulating levels and rheumatoid arthritis (RA), a total of 156 RA patients and 125 controls were recruited into the study. An association of -855 C/G MCP-1 polymorphism to IgM RF within the RA patients was observed. The lowest circulating levels of RANTES were observed in the AA variant of RANTES -403 G/A polymorphism. Furthermore, an association of -403 AA variant to circulating levels of IL-15 and IL-10 was found. No associations of factors describing rheumatoid arthritis (RFs, ANA, anti-CCP-positive/negative, DAS 28 score and number of swollen joints) with MCP-1 levels, genotype distribution, allelic frequencies and/or frequencies of haplotypes composed of all three studied polymorphisms in promoter region of MCP-1, and RANTES polymorphism were observed. We conclude that the RANTES promoter polymorphism is associated to circulating levels of RANTES, IL15 and IL10. However, our findings suggest that polymorphisms in the MCP-1 and RANTES gene promoters do not contribute significantly to the interindividual RA susceptibility and/or severity in Caucasians.

Morbidly obese human subjects have increased peripheral blood CD4+ T cells with skewing toward a Treg- and Th2-dominated phenotype

Obesity is associated with local T-cell abnormalities in adipose tissue. Systemic obesity-related abnormalities in the peripheral blood T-cell compartment are not well defined. In this study, we investigated the peripheral blood T-cell compartment of morbidly obese and lean subjects. We determined all major T-cell subpopulations via six-color flow cytometry, including CD8+ and CD4+ T cells, CD4+ T-helper (Th) subpopulations, and natural CD4+CD25+FoxP3+ T-regulatory (Treg) cells. Moreover, molecular analyses to assess thymic output, T-cell proliferation (T-cell receptor excision circle analysis), and T-cell receptor-β (TCRB) repertoire (GeneScan analysis) were performed. In addition, we determined plasma levels of proinflammatory cytokines and cytokines associated with Th subpopulations and T-cell proliferation. Morbidly obese subjects had a selective increase in peripheral blood CD4+ naive, memory, natural CD4+CD25+FoxP3+ Treg, and Th2 T cells, whereas CD8+ T cells were normal. CD4+ and CD8+ T-cell proliferation was increased, whereas the TCRB repertoire was not significantly altered. Plasma levels of cytokines CCL5 and IL-7 were elevated. CD4+ T-cell numbers correlated positively with fasting insulin levels. The peripheral blood T-cell compartment of morbidly obese subjects is characterized by increased homeostatic T-cell proliferation to which cytokines IL-7 and CCL5, among others, might contribute. This is associated with increased CD4+ T cells, with skewing toward a Treg- and Th2-dominated phenotype, suggesting a more anti-inflammatory set point.

Serum chemokines RANTES and monocyte chemoattractant protein-1 in Egyptian patients with atopic asthma: relationship to disease severity

BACKGROUND AND AIMS

Asthma is a highly prevalent, complex inflammatory disease of the airways often associated with bronchial hyperreactivity and atopy. The chemokine RANTES (regulated upon activation, normal T -cell expressed and secreted) is an important element for the chemotaxis at the site of allergic inflammation. This study aimed to assess the serum levels of the chemokines RANTES and monocyte chemoattractant protein-1 (MCP-1) in Egyptian patients with atopic asthma and to evaluate their possible relation t the severity of airway obstruction.

METHODS

The study included 60 Egyptian patients with atopic asthma and 20 healthy volunteers. Serum levels of the chemokines RANTES and MCP-1 were measured. Total serum IgE level and absolute eosinophil counts were determined. The severity of airway obstruction was assessed using spirometric measurement (FEV(1)).

RESULTS

The serum levels of RANTES were significantly higher in all asthmatic patients than the controls (p <0.001). Moreover, RANTES levels were significantly increased in patients with moderate and severe asthma as compared to those with mild asthma (p <0.001). Serum RANTES correlated positively with absolute eosinophil counts and total serum IgE and negatively with FEV(1), whereas there was no significant correlation with serum MCP-1 in all asthmatic patients.

CONCLUSIONS

Serum RANTES may be used as a useful noninvasive marker of airway obstruction and a potential diagnostic tool for monitoring asthma severity. In this regard, identification and blocking of this chemokine and/or its receptor may be a promising therapeutic approach to asthmatic patients.