Absence of the estrogen receptor alpha (ER) in human breast cancer cells is an indicator of poor prognosis, and predictive of lack of response to hormonal therapy. Previous studies in our laboratory and others have shown that epigenetic regulation, including DNA methylation and histone deacetylation, are common mechanisms leading to ER gene silencing. Through the use of pharmacologic inhibitors, 5-aza 2'deoxycytidine (AZA) and Trichostatin A (TSA), we have shown that alterations in both of these mechanisms results in synergistic reexpression of ER mRNA and functional protein. These alterations may play a larger role in stimulation of cell signaling pathways leading to ER expression. We have utilized newly developed genome wide screening microarray techniques to identify gene(s) contributing to the hormone independent phenotype and AZA/TSA mediated ER expression. From this screen, we identified and confirmed expression of 4 candidate genes (PP2A, XCL1, THY1 and NBC4) as potential regulators of the hormone independent phenotype. Expression of two genes, XCL1 and PP2A, appeared to be correlated with ER expression. PP2A expression was not changed with ER degradation using ICI 182,780 whereas XCL1 expression decreased in the presence of AZA/TSA and ICI 182,780. This suggests that PP2A may be a determinant of ER expression while XCL1 appears to be ER responsive and downstream of ER expression. These gene products may be novel targets to be further explored in the development of new therapeutics for ER negative breast cancer.

OBJECTIVE

The clinical outcome of patients with severe head injuries is still critically dependent on their secondary injuries. Although hypoxia and hypotension appear to mediate a substantial proportion of secondary injuries, many studies associate secondary brain injury with neuroinflammatory responses. Chemokines have been detected in the cerebrospinal fluid but not in the brain tissue of patients with head trauma. This study was performed to determine if chemokines were expressed in pericontusional brain tissue in patients with moderate or severe head trauma who underwent surgical evacuation of their brain contusions.

METHODS

Twelve patients with posttraumatic cerebral contusion requiring a surgical evacuation were studied. A 20- to 40-mg sample of white matter was removed from the surgical cavity in the pericontusional area. Two patients undergoing elective surgery for clip ligation of an unruptured aneurysm were used as controls. The median interval from trauma to biopsy procedure was 44 hours (range 3-360 hours). Total RNA was isolated from these samples and a ribonuclease protection assay was performed to measure the mRNA levels of several chemokines: CCL2, CCL3, CCL4, CCL5, CXCL8, CXCL1XCL1.

RESULTS

The CCL2, a monocyte chemoattractant produced by activated astrocytes, was the most strongly expressed chemokine, followed by CXCL8, CCL3, and CCL4. The chemokines CXCL1XCL1 was not detected.

CONCLUSIONS

Chemokine activation occurs early after moderate or severe head trauma and is maintained for several days after trauma. This event may contribute to neuroinflammatory exacerbation of posttraumatic brain damage in the pericontusional brain tissue.

We have applied an efficient solid-phase protein refolding method to the milligram scale production of natively folded recombinant chemokine proteins. Chemokines are intensely studied proteins because of their roles in immune system regulation, response to inflammation, fetal development, and numerous disease states including, but not limited to, HIV-1/AIDS, cancer metastasis, Crohn's disease, asthma and arthritis. Many investigators use recombinant chemokines for research purposes, however these proteins partition almost exclusively to the inclusion body fraction when produced in Escherichia coli. A major hurdle is to correctly refold the chemokine and oxidize the two highly conserved disulfide bonds found in nearly all chemokines. Conventional methods for oxidation and refolding by dialysis or extreme dilution are effective but slow and yield large volumes of dilute chemokine. Here we use an on-column approach for rapid refolding and oxidation of four chemokines, CXCL1XCL1/lymphotactin, and CX3CL1/fractalkine. NMR spectra of SDF-1alpha, RANTES, lymphotactin, and fractalkine indicate these chemokines adopt native structures. On-column refolded SDF-1alpha is fully active in an intracellular calcium flux assay. Our success with multiple SDF-1alpha mutants and members of all four chemokine subfamilies suggests that on-column refolding is a robust method for preparative-scale production of recombinant chemokine proteins.

The recent Zika pandemic in the Americas is linked to congenital birth defects and Guillain-Barré syndrome. White blood cells (WBCs) play an important role in host immune responses early in arboviral infection. Infected WBCs can also function as 'Trojan horses' and carry viruses into immune-sheltered spaces, including the placenta, testes and brain. Therefore, defining which WBCs are permissive to Zika virus (ZIKV) is critical. Here, we analyse ZIKV infectivity of peripheral blood mononuclear cells (PBMCs) in vitro and from Nicaraguan Zika patients and show CD14+CD16+ monocytes are the main target of infection, with ZIKV replication detected in some dendritic cells. The frequency of CD14+ monocytes was significantly decreased, while the CD14+CD16+ monocyte population was significantly expanded during ZIKV infection compared to uninfected controls. Viral RNA was detected in PBMCs from all patients, but in serum from only a subset, suggesting PBMCs may be a reservoir for ZIKV. In Zika patients, the frequency of infected cells was lower but the percentage of infected CD14+CD16+ monocytes was significantly higher compared to dengue cases. The gene expression profile in monocytes isolated from ZIKV- and dengue virus-infected patients was comparable, except for significant differences in interferon-γ, CXCL1XCL1, interleukin-6 and interleukin-10 levels. Thus, our study provides a detailed picture of the innate immune profile of ZIKV infection and highlights the important role of monocytes, and CD14+CD16+ monocytes in particular.

Intestinal immune homeostasis requires dynamic crosstalk between innate and adaptive immune cells. Dendritic cells (DCs) exist as multiple phenotypically and functionally distinct sub-populations within tissues, where they initiate immune responses and promote homeostasis. In the gut, there exists a minor DC subset defined as CD103(+)CD11b(-) that also expresses the chemokine receptor XCR1. In other tissues, XCR1(+) DCs cross-present antigen and contribute to immunity against viruses and cancer, however the roles of XCR1(+) DCs and XCR1 in the intestine are unknown. We showed that mice lacking XCR1(+) DCs are specifically deficient in intraepithelial and lamina propria (LP) T cell populations, with remaining T cells exhibiting an atypical phenotype and being prone to death, and are also more susceptible to chemically-induced colitis. Mice deficient in either XCR1 or its ligand, XCL1, similarly possess diminished intestinal T cell populations, and an accumulation of XCR1(+) DCs in the gut. Combined with transcriptome and surface marker expression analysis, these observations lead us to hypothesise that T cell-derived XCL1 facilitates intestinal XCR1(+) DC activation and migration, and that XCR1(+) DCs in turn provide support for T cell survival and function. Thus XCR1(+) DCs and the XCR1/XCL1 chemokine axis have previously-unappreciated roles in intestinal immune homeostasis.

BACKGROUND

CXC chemokines are induced by inflammatory stimuli in epithelial cells and some, like MIG/CXCL9, IP-10/C<em>XCL1</em>0 and I-TAC/C<em>XCL1</em>1, are antibacterial for Streptococcus pyogenes.

RESULTS

SpeB from S. pyogenes degrades a wide range of chemokines (i.e. IP10/C<em>XCL1</em>0, I-TAC/C<em>XCL1</em>1, PF4/CXCL4, GROalpha/C<em>XCL1</em>, GRObeta/CXCL2, GROgamma/CXCL3, ENA78/CXCL5, GCP-2/CXCL6, NAP-2/CXCL7, SDF-1/C<em>XCL1</em>2, BCA-1/C<em>XCL1</em>3, BRAK/C<em>XCL1</em>4, SRPSOX/C<em>XCL1</em>6, MIP-3alpha/CCL20, Lymphotactin/<em>XCL1</em>, and Fractalkine/CX3CL1), has no activity on IL-8/CXCL8 and RANTES/CCL5, partly degrades SRPSOX/C<em>XCL1</em>6 and MIP-3alpha/CCL20, and releases a 6 kDa CXCL9 fragment. C<em>XCL1</em>0 and C<em>XCL1</em>1 loose receptor activating and antibacterial activities, while the CXCL9 fragment does not activate the receptor CXCR3 but retains its antibacterial activity.

CONCLUSIONS

SpeB destroys most of the signaling and antibacterial properties of chemokines expressed by an inflamed epithelium. The exception is CXCL9 that preserves its antibacterial activity after hydrolysis, emphasizing its role as a major antimicrobial on inflamed epithelium.

Chemokine-mediated recruitment of regulatory cell subsets to the airway during inflammation and enhancement of their activities are potential strategies for therapeutic development in allergic asthma (AA). In this study, we aim to explore the role of XCL1, a chemokine associated with immune suppression and allergy, on CD4(+)CD25(high)CD127(low/-) regulatory T cell (Treg) function in AA. Flow cytometry and PCR analysis showed a reduction in XCL1 and XCR1 expression in AA Treg compared with healthy control and nonallergic asthmatic counterparts. This reduction in XCL1 expression was associated with the suboptimal regulatory function of Treg in AA. Interestingly, incubation with recombinant human XCL1 significantly increased Treg-mediated suppression and cytotoxicity by up-regulating expression of XCL1 and chief effector molecules of Treg function. Altogether, these results suggest an association between dysregulated XCL1 expression and reduced Treg activities in AA, as well as a potential role of XCL1 in reversing defective Treg function in the disease.

CD8 T cell immune responses are known not to be essential during the initial stages of infection with Mycobacterium tuberculosis (Mtb), but their presence becomes important as the chronic infection ensues. The basis of this is still not clear. In previous studies, we showed that CD8 T cells have a distinctive positioning in the architecture of the granuloma lesion, with further changes throughout the course of the chronic infection. We have also hypothesized that further movement of lymphocytes once they are within the lung lesions could be associated with the levels of expression of the chemokine XCL1 (lymphotactin). XCL1 is produced mainly by activated CD8 T cells, and its chemotactic activity seems primarily controlling movement of CD4 and CD8 T cells. In this study, using a murine low-dose aerosol infection model coupled with antibody depletion of T cell subsets, we investigated the role of CD8 T cells in the control of the bacterial growth and in the pathogenesis of the disease in mice at early, mid, or late stages of the chronic disease state. Additionally, we also describe for the first time that during Mtb infection, activated CD8 T cells in the lungs produce XCL1 and that this chemokine is capable of controlling IFN-gamma production by CD4 T cells.

Large DNA viruses such as herpesvirus and poxvirus encode proteins that target and exploit the chemokine system of their host. These proteins have the potential to block or change the orchestrated recruitment of leukocytes to sites of viral infection. The genome of Kaposi sarcoma-associated herpes virus (KSHV) encodes three chemokine-like proteins named vCCL1, vCCL2, and vCCL3. In this study vCCL3 was probed in parallel with vCCL1 and vCCL2 against a panel of the 18 classified human chemokine receptors. In calcium mobilization assays vCCL1 acted as a selective CCR8 agonist, whereas vCCL2 was found to act as a broad spectrum chemokine antagonist of human chemokine receptors, including the lymphotactin receptor. In contrast vCCL3 was found to be a highly selective agonist for the human lymphotactin receptor XCR1. The potency of vCCL3 was found to be 10-fold higher than the endogenous human XCL1 chemokine in respect to phosphatidylinositol turnover and calcium mobilization as well as chemotaxis. High expression of XCR1 was found in placenta and neutrophils by real-time PCR. These data are consistent with reports of different expression profiles for vCCL2 and vCCL3 during the life cycle of KSHV, indicate a novel, sophisticated exploitation by the virus of specifically the lymphotactin receptor by both agonist and antagonist mechanisms, and suggest a unique physiological importance of this (somewhat overlooked) chemokine receptor.

Mice infected for 60 days with Mycobacterium tuberculosis were treated with aerosolized XCL1-targeting small interfering RNA (siRNA) to induce local and transient suppression of XCL1/lymphotactin (an important chemokine in tuberculoid granuloma formation). The local pulmonary siRNA therapy resulted in a 50% decrease in the total amount of xcl1 gene transcripts at 3 days, and 40 to 50% protein suppression 3 and 5 days after treatment. Reduced XCL1 expression in the lungs was associated with decreased numbers of T lymphocytes, reduction in the IFN-gamma response, disorganized granulomatous lesions, and higher fibrosis when compared with control mice treated with either PBS or nontargeting siRNA. This indicates that a transient but strong modulation of the production of XCL1 in the lungs has a significant effect on the influx of IFN-gamma-secreting T cells, as well as local pathology, but without significantly altering containment of the infection.

During early pregnancy, decidual innate lymphoid cells (dILCs) interact with surrounding maternal cells and invading fetal extravillous trophoblasts (EVT). Here, using mass cytometry, we characterise five main dILC subsets: decidual NK cells (dNK)1-3, ILC3s and proliferating NK cells. Following stimulation, dNK2 and dNK3 produce more chemokines than dNK1 including XCL1 which can act on both maternal dendritic cells and fetal EVT. In contrast, dNK1 express receptors including Killer-cell Immunoglobulin-like Receptors (KIR), indicating they respond to HLA class I ligands on EVT. Decidual NK have distinctive organisation and content of granules compared with peripheral blood NK cells. Acquisition of KIR correlates with higher granzyme B levels and increased chemokine production in response to KIR activation, suggesting a link between increased granule content and dNK1 responsiveness. Our analysis shows that dILCs are unique and provide specialised functions dedicated to achieving placental development and successful reproduction.

Understanding dendritic cell (DC) subset functions should lead to the development of novel types of vaccine. Here we characterized expression of XC chemokine receptor 1 (XCR1) and its ligand, XCL1. Murine XCR1 was the only chemokine receptor selectively expressed in CD8alpha(+) conventional DCs. XCL1 was constitutively expressed in NK cells, which contribute to serum XCL1 levels. NK and CD8(+) T cells increased XCL1 production upon activation. These expression patterns were conserved in human blood cells, including the BDCA3(+) DC subset. Thus, in human and mice, certain DC subsets should be chemotactic towards NK or activated CD8(+) T cells through XCR1.

Our previous studies showed that the non-psychoactive cannabinoid, cannabidiol (CBD), ameliorates the clinical symptoms in mouse myelin oligodendrocyte glycoprotein (MOG)35-55-induced experimental autoimmune encephalomyelitis model of multiple sclerosis (MS) as well as decreases the memory MOG35-55-specific T cell (TMOG) proliferation and cytokine secretion including IL-17, a key autoimmune factor. The mechanisms of these activities are currently poorly understood.

Herein, using microarray-based gene expression profiling, we describe gene networks and intracellular pathways involved in CBD-induced suppression of these activated memory TMOG cells. Encephalitogenic TMOG cells were stimulated with MOG35-55 in the presence of spleen-derived antigen presenting cells (APC) with or without CBD. mRNA of purified TMOG was then subjected to Illumina microarray analysis followed by ingenuity pathway analysis (IPA), weighted gene co-expression network analysis (WGCNA) and gene ontology (GO) elucidation of gene interactions. Results were validated using qPCR and ELISA assays.

Gene profiling showed that the CBD treatment suppresses the transcription of a large number of proinflammatory genes in activated TMOG. These include cytokines (Xcl1, Il3, Il12a, Il1b), cytokine receptors (Cxcr1, Ifngr1), transcription factors (Ier3, Atf3, Nr4a3, Crem), and TNF superfamily signaling molecules (Tnfsf11, Tnfsf14, Tnfrsf9, Tnfrsf18). "IL-17 differentiation" and "IL-6 and IL-10-signaling" were identified among the top processes affected by CBD. CBD increases a number of IFN-dependent transcripts (Rgs16, Mx2, Rsad2, Irf4, Ifit2, Ephx1, Ets2) known to execute anti-proliferative activities in T cells. Interestingly, certain MOG35-55 up-regulated transcripts were maintained at high levels in the presence of CBD, including transcription factors (Egr2, Egr1, Tbx21), cytokines (Csf2, Tnf, Ifng), and chemokines (Ccl3, Ccl4, Cxcl10) suggesting that CBD may promote exhaustion of memory TMOG cells. In addition, CBD enhanced the transcription of T cell co-inhibitory molecules (Btla, Lag3, Trat1, and CD69) known to interfere with T/APC interactions. Furthermore, CBD enhanced the transcription of oxidative stress modulators with potent anti-inflammatory activity that are controlled by Nfe2l2/Nrf2 (Mt1, Mt2a, Slc30a1, Hmox1).

Microarray-based gene expression profiling demonstrated that CBD exerts its immunoregulatory effects in activated memory TMOG cells via (a) suppressing proinflammatory Th17-related transcription, (b) by promoting T cell exhaustion/tolerance, (c) enhancing IFN-dependent anti-proliferative program, (d) hampering antigen presentation, and (d) inducing antioxidant milieu resolving inflammation. These findings put forward mechanism by which CBD exerts its anti-inflammatory effects as well as explain the beneficial role of CBD in pathological memory T cells and in autoimmune diseases.

The present gold standard for bladder cancer is Mycobacterium bovis, Bacillus Calmette Guerin (BCG) immunotherapy. But it has a non-responder rate of 30-50% and side effects are common. Lactobacillus casei strain Shirota has been reported to reduce the incidence of recurrence in bladder cancer patients and to cure tumor-bearing mice. Our aim was to determine if Lactobacillus rhamnosus GG (LGG) could be as efficacious as BCG in a murine model of bladder cancer. MB49 bladder cancer cells secreting human prostate-specific antigen were implanted orthotopically in female C57BL/6 mice and urinary prostate-specific antigen levels were used as a marker of tumor growth. Mice were treated with either live or lyophilized LGG given via intravesical instillation, or both oral and intravesical LGG given once a week for a period of 6 weeks starting at day 4 after tumor implantation. A comparison of LGG and BCG immunotherapy was also carried out. LGG therapy (live or lyophilized) significantly (P = 0.006) increased the number of cured mice. Cytokine arrays and immune cell recruitment analysis revealed differences between untreated, treated, cured, and tumor-bearing mice. LGG therapy restored XCL1 levels to those in healthy bladders. LGG also recruited large numbers of neutrophils and macrophages to the tumor site. Intravesical LGG and BCG immunotherapy had cure rates of 89 and 77%, respectively, compared with 20% in untreated mice. LGG has the potential to replace BCG immunotherapy for the treatment of bladder cancer.

BACKGROUND

The chemotactic signals regulating cell trafficking in the herpes simplex virus type 1 (HSV-1) infected cornea are well documented, however, those in the cornea-associated tissues, such as the trigeminal ganglion (TG) and draining lymph nodes (LNs), are largely unknown.

OBJECTIVE

To examine chemokine expression and subsequent cell infiltration in the HSV-1 infected cornea and its associated tissues.

METHODS

Eight-week-old female BALB/c mice were infected with 10 mu l HSV-1 (CHR3 strain: 5 x 106 PFU/ml) by corneal scarification. Total RNAs were extracted from the corneas, TGs, and LNs at pre-inoculation, 3 days post-inoculation (P.I.) and 7 days P.I. The mRNA for 28 different chemokines in the extracts was amplified by RT-PCR. Infiltrating cells were identified by immunohistochemistry.

RESULTS

After the HSV-1 infection, the corneal stroma became edematous by infiltrated cells under the eroded epithelium. The TG and LNs were markedly swollen. The cornea was infiltrated with granulocytes and CD11b+ cells at 3 days P.I., followed by CD4+ and CD8+ T cells at 12 days P.I. In the TG, CD11b+ cells, but no granulocytes, infiltrated throughout the observation period. T cells migrated into the TG earlier than into the cornea. Gene expressions of neutrophil-attracting chemokines (C<em>XCL1</em>, 2, 3, and 5) increased in the cornea, but they did not enhance in the TG or LNs. On the other hand, gene expressions of chemokines which attract CD11b+ cells such as CCL2, 8, 7, 12, CCL3, 4, and CCL5, increased in the cornea and TG with its peak at 3 days P.I. Gene expressions of chemokines those work on T cells and B cells, such as CCL19, CCL21, CXCL9, C<em>XCL1</em>3, C<em>XCL1</em>0, <em>XCL1</em>, and C<em>XCL1</em>6, were up-regulated and peaked at 3 days P.I. in the cornea and in the TG. Thus, pattern of chemokine gene expression was similar in the cornea and in the TG. On the contrary, gene expressions of chemokines in the draining LNs affecting CD11b+ cells and T cells were temporarily down-regulated.

CONCLUSIONS

Upon HSV-1 infection, dynamic gene expression of chemokines was observed not only in the inoculated cornea but also in its associated tissues.

Mast cells are key effector cells of immediate type allergic reactions. Upon activation they release a broad array of pre-stored and de novo synthesized mediators including immunoregulatory cytokines and chemokines. Here, we analyzed the chemokine profile expressed by mature human mast cells. Human mast cells were isolated from intestinal tissue and cultured with stem cell factor (SCF) in the presence or absence of IL-4 for 10d. Cells were stimulated by cross-linking of the high affinity IgE receptor (FcεRI) and/or by SCF. Chemokine and chemokine receptor mRNA expression was determined by real-time RT-PCR and chemokine release was measured by multiplex bead immunoassay. Out of 43 chemokines and 19 chemokine receptors human intestinal mast cells express 27 chemokines and nine chemokine receptors. Twelve chemokines (CCL1, CCL2, CCL3, CCL4, CCL5, CCL7, CCL18, CCL20, CXCL2, CXCL3, CXCL8, and XCL1) were more than four-fold up-regulated in response to FcεRI cross-linking. Combination of pre-culture with IL-4 and/or stimulation with SCF in addition to FcεRI cross-linking further increased the antigen-dependent expression of mRNA for most chemokines. In contrast, the expression of CCL20, CXCL2, and CXCL3 was strongly inhibited by IL-4 treatment. In conclusion, human intestinal mast cells express a broad spectrum of different chemokines underlining their important role as immunoregulatory cells. Furthermore, combined treatment with IL-4 and SCF increases the antigen-mediated expression and release of multiple chemokines, but IL-4 priming inhibits the expression of CCL20, CXCL2, and CXCL3.

Following infection with Leishmania major, the chemokines <em>XCL1</em>, C<em>XCL1</em>0, and CCL2 were preferentially expressed in draining lymph nodes of resistant mice. Neutralization of interleukin 12 (IL-12) or gamma interferon in resistant mice resulted in decreased chemokine expression, while administration of IL-12 to susceptible mice resulted in an increase in the level of chemokine gene expression.

Sertoli cells, the primary somatic cell in the seminiferous epithelium, provide the spermatogonial stem cell (SSC) microenvironment (niche) through physical support and the expression of paracrine factors. However, the regulatory mechanisms within the SSC niche, which is primarily controlled by Sertoli cells, remain largely unknown. GATA4 is a Sertoli cell marker, involved in genital ridge initiation, sex determination and differentiation during the embryonic stage. Here, we showed that neonatal mice with a targeted disruption of Gata4 in Sertoli cells (Gata4(flox/flox); Amh-Cre; hereafter termed Gata4 cKO) displayed a loss of the establishment and maintenance of the SSC pool and apoptosis of both gonocyte-derived differentiating spermatogonia and meiotic spermatocytes. Thus, progressive germ cell depletion and a Sertoli-cell-only syndrome were observed as early as the first wave of murine spermatogenesis. Transplantation of germ cells from postnatal day 5 (P5) Gata4 cKO mice into Kit(W/W-v) recipient seminiferous tubules restored spermatogenesis. In addition, microarray analyses of P5 Gata4 cKO mouse testes showed alterations in chemokine signaling factors, including Cxcl12, Ccl3, Cxcr4 (CXCL12 receptor), Ccr1 (CCL3 receptor), Ccl9, Xcl1 and Ccrl2. Deletion of Gata4 in Sertoli cells markedly attenuated Sertoli cell chemotaxis, which guides SSCs or prospermatogonia to the stem cell niche. Finally, we showed that GATA4 transcriptionally regulated Cxcl12 and Ccl9, and the addition of CXCL12 and CCL9 to an in vitro testis tissue culture system increased the number of PLZF+ undifferentiated spermatogonia within Gata4 cKO testes. Together, these results reveal a novel role for GATA4 in controlling the SSC niche via the transcriptional regulation of chemokine signaling shortly after birth.

Lymphotactin/XCL1, the defining member of the C class of chemokines, undergoes a conformational change that involves the complete restructuring of all stabilizing interactions. Other chemokines are restricted to a single conformation by a pair of conserved disulfide crosslinks, one of which is absent in lymphotactin. This structural interconversion is entirely reversible, and the two-state equilibrium is sensitive to changes in temperature and ionic strength. One species adopts the conserved chemokine fold as a monomer and functions as an agonist for XCR1, the specific G-protein-coupled receptor for lymphotactin. Rearrangement to the other conformation produces a novel four-stranded sheet that dimerizes to form a beta sandwich with high affinity for cell-surface glycosaminoglycans. We developed methods for resolving the two species and investigated the dynamics of human lymphotactin structural interconversion with NMR spectroscopy, heparin affinity chromatography, and time-resolved fluorescence on the wild-type protein and a panel of amino acid-substituted lymphotactin variants. Our results show that the lymphotactin structural rearrangement occurs at a rate of approximately 1/s and that mutation of residues required for glycosaminoglycan binding shifts the conformational equilibrium toward the chemokine-like fold. We speculate that charge repulsion between arginines 23 and 43 destabilizes the chemokine fold and promotes conversion to the novel lymphotactin dimer, whereas binding of chloride or another anion stabilizes the chemokine fold by neutralizing the repulsive effect.

Inflammatory mediators, including cytokines, contribute to neuronal and axonal dysfunction and cell death. To examine the roles of cytokines in pathogenesis and regeneration in the central nervous system (CNS), we analyzed effects of cytokines on early gene regulation (6h) in neuronal cultures, employing gene arrays. Our hypothesis is that neuronal gene expression is differentially regulated in vitro by cytokine mixtures typical of Th1 and Th2 T cells and monocytes/macrophages (M/M). Th1 and M/M cytokines showed similar patterns for regulation of numerous pathways including cytokine-receptor interactions, MAP kinase, toll like receptors, apoptosis, PPAR signaling, cell adhesion molecules (CAMS), antigen processing, adipocytokine, and JAK-STAT signaling. M/M cytokines uniquely regulated genes in T cell, B cell and ECM receptor signaling pathways. Th2 cytokines had few effects on pathways regulated by Th1 and MM cytokines, but uniquely regulated genes related to neuroactive ligand-receptors and calcium. Th1 and MM cytokines markedly upregulated a wide array of cytokine-related genes. Notably, M/M cytokines uniquely upregulated G-CSF, GM-CSF, CXCL5 and lymphotactin (Xcl1). Th2 cytokines did not upregulate cytokine-related genes, with the exception of CCL11 and FMS-like tyrosine kinase 1, a VEGF receptor. In neuroactive ligand-receptor pathways, Th1 and M/M cytokines upregulated gene expression for tryptophan hydroxylase. Th1 cytokines upregulated gene expression for GABA A receptor, delta, while Th2 cytokines downregulated GABA A receptor, gamma 3. Significant changes occurred in several genes in the wnt and Notch signaling pathways, which are highly conserved and play critical roles in neuronal and glial differentiation. In the ubiquitin-proteasome pathway, proinflammatory cytokine mixtures induced upregulation of several genes, notably ubiquitin D (Ubd/FAT10), ubiquitin ligase and several proteasomal proteins. In agreement with microarray results, QRT-PCR showed marked upregulation of gene expression for Ubd with Th1 and M/M, for transglutaminase 2 with M/M, and for arginase 1 with Th2 cytokines. Expression of Ubd in the nervous system has not been previously reported. Both message and protein for Ubd are expressed in neurons, and upregulated by pro-inflammatory cytokines. Transglutaminase 2 has been implicated in neurodegenerative diseases, and proposed as a therapeutic target. Upregulation of arginase by Th2 cytokines could be potentially neuroprotective by decreasing NO generation and enhancing neurite outgrowth. Our analysis of changes in neuronal gene expression at the time of initial exposure to an abnormal cytokine milieu provides the opportunity to identify early changes that could be reversed to prevent later irreversible neuronal damage and death in multiple sclerosis and other CNS diseases.

In this study, we screened the anti-tumor activity of murine chemokines including CCL17, CCL19, CCL20, CCL21, CCL22, CCL27, XCL1, and CX3CL1 by inoculating murine B16BL6, CT26, or OV-HM tumor cells, all of which were transfected with chemokine-expressing fiber-mutant adenovirus vector, into immunocompetent mice. A tumor-suppressive effect was observed in mice inoculated with CCL19/B16BL6 and XCL1/B16BL6, and CCL22/OV-HM showed considerable retardation in tumor growth. In the cured mice inoculated with CCL22/OV-HM, a long-term specific immune protection against parental tumor was developed. However, we were unable to identify the chemokine that had a suppressive activity common to all three tumor models. Furthermore, an experiment using chemokine-transfected B16BL6 cells was also performed on mice sensitized with melanoma-associated antigen. A drastic enhancement of the frequency of complete rejection was observed in mice inoculated with CCL17-, CCL19-, CCL22-, and CCL27-transfected B16BL6. Altogether, our results suggest that the tumor-suppressive activity of chemokine-gene immunotherapy is greatly influenced by the kind of tumor and the activation state of the host's immune system.

Recruitment of neutrophils into alveolar air spaces is an early event in the pathogenesis of pneumonia due to Streptococcus pneumoniae. This results from chemokines released by activated endothelial and epithelial cells and alveolar macrophages. Culture supernatants of 6 wild-type strains of S. pneumoniae, shown to contain choline-binding protein A (CbpA; clades A and B), induced release of chemokine CXCL8 from the human alveolar epithelial cell line A549, whereas a CbpA deletion mutant elicited significantly reduced CXCL8 release, compared with that of its isogenic parent (P<.01). Recombinant CbpA up-regulated expression of messenger RNA of CXCL8 and CCL2 but not of XCL1, CXCL1XCL1, and CXCL5 in a dose- and time-dependent manner. CbpA also increased the expression of intercellular adhesion molecule 1 (CD54) by A549 cells. Thus, CbpA of S. pneumoniae induces the transcription and release of proinflammatory molecules by human alveolar epithelial cells.

Chemokines play a critical role in the acute transplant rejection. In order to provide an overview of the chemokine expression during the course of acute allograft rejection, the intragraft expression profile of 11 chemokines representative of all four chemokine subfamilies was analyzed in a murine skin transplantation model of acute rejection. It was found that RANTES/CCL5, TARC/CCL17 and FKN/CX(3)CL1 were expressed at equivalent levels in iso- and allografts. However, the other eight chemokines expression was up-regulated to some extent in allograft compared with that in isograft. The levels of MIP-1alpha/CCL3, MIP-3alpha/CCL20 and CTACK/CCL27 were progressively increased from early stage (day 3 post-transplantation) to late stage (day 11). Mig/CXCL9, IP-10/CXCL1XCL1XCL1XCL1 expression was elevated at middle stage (day 7), and peaked at late stage. Among the up-regulated chemokines, I-TAC was the most obviously elevated chemokine. Therefore, the effect of I-TAC on the skin acute allograft rejection was evaluated. Block of I-TAC by the intradermal injection of anti-I-TAC monoclonal antibody (mAb) reduced the number of CXCR3(+) cells in skin allograft and significantly prolonged the skin allograft survival. The mAb treatment did not influence the proliferation of the intragraft infiltrating cells in response to the allogeneic antigens, but significantly decreased the number of the infiltrating cells and consequently lowered the secretion of IFN-gamma and TNF-alpha. These data indicate I-TAC might be a dominant chemokine involved in the intradermal infiltration and I-TAC-targeted intervening strategies would have potential application for the alleviation of acute transplant rejection.

Our goal in the present study was to evaluate antitumor effects and frequency of tumor-infiltrating immune cells upon intratumoral injection of RGD fiber-mutant adenoviral vector (AdRGD) encoding the chemokines CCL17, CCL19, CCL20, CCL21, CCL22, CCL27, XCL1, and CX3CL1. Among eight kinds of chemokine-expressing AdRGDs, AdRGD-CCL19 injection most efficiently induced infiltration of T cells into established B16BL6 tumor parenchyma, whereas most of these T cells were perforin-negative in immunohistochemical analysis. Additionally, the growth of AdRGD-CCL19-injected tumors decreased only slightly as well as that of other tumors treated with each chemokine-expressing AdRGD, which indicated that accumulation of naive T cells in tumor tissue does not effectively damage the tumor cells. Tumor-bearing mice, in which B16BL6-specific T cells were elicited by dendritic cell-based immunization, demonstrated that intratumoral injection of AdRGD-CCL17, -CCL22, or -CCL27 could considerably suppress tumor growth and attract activated T cells. On the other hand, AdRGD-CCL19-injection in the immunized mice showed slight increase of tumor-infiltrating T cells compared to treatment using control vector. Collectively, although AdRGD-mediated chemokine gene transduction into established tumors would be very useful for augmentation of tumor-infiltrating immune cells, a combinational treatment that can systemically induce tumor-specific effector T cells is necessary for satisfactory antitumor efficacy.