Expression of rat I-TAC/CXCL11/SCYA11 during central nervous system inflammation: comparison with other CXCR3 ligands

Therapeutic potential of a novel IP-10-(anti-HER2 scFv) fusion protein for the treatment of HER2-positive breast cancer

OBJECTIVES

Interferon-γ-inducible protein 10 (IP-10) is a potent antitumor agent and acts by its angiostatic and immunomodulatory properties. IP-10 can target to tumor site by linking with single chain variable fragment (scFv) that recognized specific tumor antigen. In this study, we evaluated biological activity of the fusion protein including IP-10 and anti-HER2 scFv (IP-10-(anti-HER2 scFv)).

RESULTS

The HER2- and cell-based ELISA as well as the flow cytometry analysis demonstrated that the fusion protein specifically binds to HER2 antigen. In addition, competitive ELISA demonstrated that the fusion protein recognized the same epitope of HER2 antigen as trastuzumab. The results of MTT assay demonstrated that the growth of HER2-enriched SK-BR3 cells was inhibited in the presence of the fusion protein. Moreover, the cytotoxic effect of the fusion protein was not significantly different from that of trastuzumab. However, no significant cytotoxic effect compared to trastuzumab and anti-HER2 scFv was observed in HER2-low-expressing MDA-MB-231 cells. The obtained findings demonstrated that IP-10-(anti-HER2 scFv) can selectively reduce the cell viability in HER2⁺ cells. Moreover, similar inhibitory effect on growth of both SK-BR-3 and MDA-MB-231 cell lines was observed in the presence of anti-HER2 scFv protein even at high concentration after 72 h. The chemotaxis properties of the fusion protein were also analyzed by a chemotaxis assay. It was demonstrated that the fusion protein induced migration of activated T cell similar to recombinant IP-10 protein.

CONCLUSIONS

Our findings suggested that IP-10-(anti-HER2 scFv) fusion protein can specifically direct IP-10 to the HER2-expressing tumor cells and may act as an adjuvant along with HER2-based vaccine to gather the elicited immune response at the site of HER2-overexpressimg tumors.

Obesity-induced neuroinflammation and cognitive impairment in young adult versus middle-aged mice

BACKGROUND

Obesity rates are increasing worldwide. Obesity leads to many complications, including predisposing individuals to the development of cognitive impairment as they age. Immune dysregulation, including inflammaging (e.g., increased circulating cytokines) and immunosenescence (declining immune system function), commonly occur in obesity and aging and may impact cognitive impairment. As such, immune system changes across the lifespan may impact the effects of obesity on neuroinflammation and associated cognitive impairment. However, the role of age in obesity-induced neuroinflammation and cognitive impairment is unclear. To further define this putative relationship, the current study examined metabolic and inflammatory profiles, along with cognitive changes using a high-fat diet (HFD) mouse model of obesity.

RESULTS

First, HFD promoted age-related changes in hippocampal gene expression. Given this early HFD-induced aging phenotype, we fed HFD to young adult and middle-aged mice to determine the effect of age on inflammatory responses, metabolic profile, and cognitive function. As anticipated, HFD caused a dysmetabolic phenotype in both age groups. However, older age exacerbated HFD cognitive and neuroinflammatory changes, with a bi-directional regulation of hippocampal inflammatory gene expression.

CONCLUSIONS

Collectively, these data indicate that HFD promotes an early aging phenotype in the brain, which is suggestive of inflammaging and immunosenescence. Furthermore, age significantly compounded the impact of HFD on cognitive outcomes and on the regulation of neuroinflammatory programs in the brain.

CXCR3 signalling partially contributes to the pathogenesis of neuropathic pain in male rodents

BACKGROUND

Currently, there is a lack of effective therapy for chronic pain. Increasing evidence has shown that chemokines and their correlative receptors involved in the neuron-glial cell cross-talk could contribute to the pathogenesis of neuropathic pain. Our previous studies suggested that CXCR3 expression was elevated in the spinal dorsal horn after nerve injury.

OBJECTIVES

In this study, we aimed to explore the role of CXCR3 signalling in chronic pain modulation.

METHODS

Reverse transcription quantitative PCR and Western blotting were used to measure the expression of CXCR3 and its ligands in the spinal cord following chronic constriction injury (CCI) of the sciatic nerve. Cxcr3 -knockout mice were used to observe the effect of the receptor on pain-related behaviour and microglial activation. Immunohistochemistry was used to investigate the expression of two activation markers for spinal microglia, Iba-1 and phosphorylated-p38 (p-p38) in these mice.

RESULTS

The expression of CXCR3 and its ligand CXCL11 was upregulated in the lumbar dorsal horn of the spinal cord in CCI models. In Cxcr3 -knockout mice, CCI-induced tactile allodynia and thermal hyperalgesia were observed to be alleviated during the early stage of pain processing. Meanwhile, the expression of the glial activation markers, namely, Iba-1 and p-p38, was decreased.

CONCLUSION

Our results demonstrate that CXCR3 could be a key modulator involved in pain modulation of the spinal cord; therefore, CXCR3-related signalling pathways could be potential targets for the treatment of intractable pathological pain.

A peripheral inflammatory signature discriminates bipolar from unipolar depression: A machine learning approach

BACKGROUND

Mood disorders (major depressive disorder, MDD, and bipolar disorder, BD) are considered leading causes of life-long disability worldwide, where high rates of no response to treatment or relapse and delays in receiving a proper diagnosis (~60% of depressed BD patients are initially misdiagnosed as MDD) contribute to a growing personal and socio-economic burden. The immune system may represent a new target to develop novel diagnostic and therapeutic procedures but reliable biomarkers still need to be found.

METHODS

In our study we predicted the differential diagnosis of mood disorders by considering the plasma levels of 54 cytokines, chemokines and growth factors of 81 BD and 127 MDD depressed patients. Clinical diagnoses were predicted also against 32 healthy controls. Elastic net models, including 5000 non-parametric bootstrapping procedure and inner and outer 10-fold nested cross-validation were performed in order to identify the signatures for the disorders.

RESULTS

Results showed that the immune-inflammatory signature classifies the two disorders with a high accuracy (AUC = 97%), specifically 92% and 86% respectively for MDD and BD. MDD diagnosis was predicted by high levels of markers related to both pro-inflammatory (i.e. IL-1β, IL-6, IL-7, IL-16) and regulatory responses (IL-2, IL-4, and IL-10), whereas BD by high levels of inflammatory markers (CCL3, CCL4, CCL5, CCL11, CCL25, CCL27, CXCL11, IL-9 and TNF-α).

CONCLUSIONS

Our findings provide novel tools for early diagnosis of BD, strengthening the impact of biomarkers research into clinical practice, and new insights for the development of innovative therapeutic strategies for depressive disorders.

Maternal Immune Activation Alters Fetal Brain Development and Enhances Proliferation of Neural Precursor Cells in Rats

Maternal immune activation (MIA) caused by exposure to pathogens or inflammation during critical periods of neurodevelopment is a major risk factor for behavioral deficits and psychiatric illness in offspring. A spectrum of behavioral abnormalities can be recapitulated in rodents by inducing MIA using the viral mimetic, PolyI:C. Many studies have focused on long-term changes in brain structure and behavioral outcomes in offspring following maternal PolyI:C exposure, but acute changes in prenatal development are not well-characterized. Using RNA-Sequencing, we profiled acute transcriptomic changes in rat conceptuses (decidua along with nascent embryo and placenta) after maternal PolyI:C exposure during early gestation, which enabled us to capture gene expression changes provoked by MIA inclusive to the embryonic milieu. We identified a robust increase in expression of genes related to antiviral inflammation following maternal PolyI:C exposure, and a corresponding decrease in transcripts associated with nervous system development. At mid-gestation, regions of the developing cortex were thicker in fetuses prenatally challenged with PolyI:C, with females displaying a thicker ventricular zone and males a thicker cortical mantle. Along these lines, neural precursor cells (NPCs) isolated from fetal brains prenatally challenged with PolyI:C exhibited a higher rate of self-renewal. Expression of Notch1 and the Notch ligand, delta-like ligand 1, which are both highly implicated in maintenance of NPCs and nervous system development, was increased following PolyI:C exposure. These results suggest that MIA elicits rapid gene expression changes within the conceptus, including repression of neurodevelopmental pathways, resulting in profound alterations in fetal brain development.

Extracellular vesicles from mesenchymal stem cells reduce microglial-mediated neuroinflammation after cortical injury in aged Rhesus monkeys

Cortical injury, such as injuries after stroke or age-related ischemic events, triggers a cascade of degeneration accompanied by inflammatory responses that mediate neurological deficits. Therapeutics that modulate such neuroinflammatory responses in the aging brain have the potential to reduce neurological dysfunction and promote recovery. Extracellular vesicles (EVs) from mesenchymal stem cells (MSCs) are lipid-bound, nanoscale vesicles that can modulate inflammation and enhance recovery in rodent stroke models. We recently assessed the efficacy of intravenous infusions of MSC-EVs (24-h and 14-days post-injury) as a treatment in aged rhesus monkeys (Macaca mulatta) with cortical injury that induced impairment of fine motor function of the hand. Aged monkeys treated with EVs after injury recovered motor function more rapidly and more fully than aged monkeys given a vehicle control. Here, we describe EV-mediated inflammatory changes using histological assays to quantify differences in markers of neuroinflammation in brain tissue between EV and vehicle-treated aged monkeys. The activation status of microglia, the innate macrophages of the brain, is critical to cell fate after injury. Our findings demonstrate that EV treatment after injury is associated with greater densities of ramified, homeostatic microglia, along with reduced pro-inflammatory microglial markers. These findings are consistent with a phenotypic switch of inflammatory hypertrophic microglia towards anti-inflammatory, homeostatic functions, which was correlated with enhanced functional recovery. Overall, our data suggest that EVs reduce neuroinflammation and shift microglia towards restorative functions. These findings demonstrate the therapeutic potential of MSC-derived EVs for reducing neuroinflammation after cortical injury in the aged brain.

The Central Nervous System Contains ILC1s That Differ From NK Cells in the Response to Inflammation

Innate lymphoid cells (ILCs) are tissue resident cells with organ-specific properties. Here, we show that the central nervous system (CNS) encompasses ILCs. In particular, CD3^-NK1.1⁺ cells present in the murine CNS comprise natural killer (NK) cells, ILC1s, intermediate ILC1s (intILC1s) and ex-ILC3s. We investigated the properties of CNS-ILC1s in comparison with CNS-NK cells during steady state and experimental autoimmune encephalomyelitis (EAE). ILC1s characteristically express CXCR3, CXCR6, DNAM-1, TRAIL, and CD200R and display heightened TNF-α production upon stimulation. In addition, ILC1s express perforin and are able to degranulate, although in a lesser extent than NK cells. Within the CNS compartments, ILC1s are enriched in the choroid plexus where very few NK cells are present, and also reside in the brain parenchyma and meninges. During EAE, ILC1s maintain stable IFN-γ and TNF-α levels while in NK cells the production of these cytokines increases as EAE progresses. Moreover, the amount of ILC1s and intILC1s increase in the parenchyma during EAE, but in contrast to NK cells, they show no signs of local proliferation. The upregulation in the inflamed brain of chemokines involved in ILC1 migration, such as CXCL9, CXCL10, and CXCL16 may lead to a recruitment of ILC1s from meninges or choroid plexus into the brain parenchyma. In sum, CNS-ILC1 phenotype, distribution and moderate inflammatory response during EAE suggest that they may act as gatekeepers involved in the control of neuroinflammation.

Pharmacological blockade of CXCR3 by (±)-NBI-74330 reduces neuropathic pain and enhances opioid effectiveness - Evidence from in vivo and in vitro studies

It has been suggested that CXCR3 is important for nociception. Our experiments were conducted to evaluate involvement of CXCR3 and its ligands (CXCL4, CXCL9, CXCL10, CXCL11/CCL21) in neuropathic pain. Our studies give new evidence that intrathecal administration of each CXCR3 ligand induces pain-like behaviour in naive mice that occurs shortly after injection due to its location of neurons, which is confirmed by immunofluorescent staining. Moreover, intrathecal administrations of CXCL9, CXCL10, CCL21 neutralizing antibodies diminished pain-related behaviour. RT-PCR/Western blot analysis unprecedentedly showed spinal elevated levels of CXCR3 after chronic constriction injury of the sciatic nerve in rats in parallel with different time-course changes of its endogenous ligands. Initially, on day 2 we observed spinal increased levels of CXCL10 and CXCL11 indicating that these chemokines have important roles in triggering neuropathy. Then, on day 7, we observed increased levels of CXCL4, CXCL9, CXCL10. Interestingly, changes in CXCL9 level persisted until day 28, suggesting that these chemokines are responsible for long-term, persistent neuropathy. Additionally, in DRG the CXCL4, CXCL9 were elevated. The results obtained from primary glial cultures, suggests that all CXCR3 ligands can be produced in microglia, but also, except for CXCL4, in astrocytes. We provide the first evidence that in neuropathy chronic intrathecal administration of CXCR3 antagonist, (±)-NBI-74330, attenuates hypersensitivity with concomitant occurrence of microglial and some of CXCR3 ligands activation observed in the spinal cord and/or DRG level. This paper underlies the significance of CXCR3 in neuropathic pain and shows therapeutic potential of its blockade for enhancement of morphine analgesia as the major novelty of this work.

Novel insights into neuroinflammation: bacterial lipopolysaccharide, tumor necrosis factor α, and Ureaplasma species differentially modulate atypical chemokine receptor 3 responses in human brain microvascular endothelial cells

BACKGROUND

Atypical chemokine receptor 3 (ACKR3, synonym CXCR7) is increasingly considered relevant in neuroinflammatory conditions, in which its upregulation contributes to compromised endothelial barrier function and may ultimately allow inflammatory brain injury. While an impact of ACKR3 has been recognized in several neurological autoimmune diseases, neuroinflammation may also result from infectious agents, including Ureaplasma species (spp.). Although commonly regarded as commensals of the adult urogenital tract, Ureaplasma spp. may cause invasive infections in immunocompromised adults as well as in neonates and appear to be relevant pathogens in neonatal meningitis. Nonetheless, clinical and in vitro data on Ureaplasma-induced inflammation are scarce.

METHODS

We established a cell culture model of Ureaplasma meningitis, aiming to analyze ACKR3 variances as a possible pathomechanism in Ureaplasma-associated neuroinflammation. Non-immortalized human brain microvascular endothelial cells (HBMEC) were exposed to bacterial lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α), and native as well as LPS-primed HBMEC were cultured with Ureaplasma urealyticum serovar 8 (Uu8) and U. parvum serovar 3 (Up3). ACKR3 responses were assessed via qRT-PCR, RNA sequencing, flow cytometry, and immunocytochemistry.

RESULTS

LPS, TNF-α, and Ureaplasma spp. influenced ACKR3 expression in HBMEC. LPS and TNF-α significantly induced ACKR3 mRNA expression (p < 0.001, vs. control), whereas Ureaplasma spp. enhanced ACKR3 protein expression in HBMEC (p < 0.01, vs. broth control). Co-stimulation with LPS and either Ureaplasma isolate intensified ACKR3 responses (p < 0.05, vs. LPS). Furthermore, stimulation wielded a differential influence on the receptor's ligands.

CONCLUSIONS

We introduce an in vitro model of Ureaplasma meningitis. We are able to demonstrate a pro-inflammatory capacity of Ureaplasma spp. in native and, even more so, in LPS-primed HBMEC, underlining their clinical relevance particularly in a setting of co-infection. Furthermore, our data may indicate a novel role for ACKR3, with an impact not limited to auto-inflammatory diseases, but extending to infection-related neuroinflammation as well. AKCR3-induced blood-brain barrier breakdown might constitute a potential common pathomechanism.

Spinal CXCL9 and CXCL11 are not involved in neuropathic pain despite an upregulation in the spinal cord following spinal nerve injury

Chemokines-mediated neuroinflammation in the spinal cord plays a critical role in the pathogenesis of neuropathic pain. Chemokine CXCL9, CXCL10, and CXCL11 have been identified as a same subfamily chemokine which bind to CXC chemokine receptor 3 to exert functions. Our recent work found that CXCL10 is upregulated in spinal astrocytes after spinal nerve ligation (SNL) and acts on chemokine receptor CXCR3 on neurons to contribute to central sensitization and neuropathic pain, but less is known about CXCL9 and CXCL11 in the maintenance of neuropathic pain. Here, we report that CXCL9 and CXCL11, same as CXCL10, were increased in spinal astrocytes after SNL. Surprisingly, inhibition of CXCL9 or CXCL11 by spinal injection of shRNA lentivirus did not attenuate SNL-induced neuropathic pain. In addition, intrathecal injection of CXCL9 and CXCL11 did not produce hyperalgesia or allodynia behaviors, and neither of them induced ERK activation, a marker of central sensitization. Whole-cell patch clamp recording on spinal neurons showed that CXCL9 and CXCL11 enhanced both excitatory synaptic transmission and inhibitory synaptic transmission, whereas CXCL10 only produced an increase in excitatory synaptic transmission. These results suggest that, although the expression of CXCL9 and CXCL11 are increased after SNL, they may not contribute to the maintenance of neuropathic pain.

The importance of chemokines in neuropathic pain development and opioid analgesic potency

The treatment of neuropathic pain resulting from nervous system malfunction remains a challenging problem for doctors and scientists. The lower effectiveness of conventionally used analgesics in neuropathic pain is associated with complex and not fully understood mechanisms of its development. Undoubtedly, interactions between immune and nervous system are crucial for maintenance of painful neuropathy. Nerve injury induces glial cell activation and thus enhances the production of numerous pronociceptive factors by these cells, including interleukins and chemokines. Increased release of those factors reduces the analgesic efficacy of opioids, which is significantly lower in neuropathic pain than in other painful conditions. This review discusses the role of chemokines from all four subfamilies as essential mediators of neuron-glia interactions occurring under neuropathic pain conditions. Based on available data, we analyse the influence of chemokines on opioid properties. Finally, we identify new direct and indirect pharmacological targets whose modulation may result in effective therapy of neuropathic pain, possibly in combination with opioids.

CXCL11 production in cerebrospinal fluid distinguishes herpes simplex meningitis from herpes simplex encephalitis

Background

The closely related herpes simplex viruses 1 and 2 can cause inflammations of the central nervous system (CNS), where type 1 most often manifest as encephalitis (HSE), and type 2 as meningitis (HSM). HSE is associated with severe neurological complications, while HSM is benign in adults. We proposed that studying the chemokine and cytokine production in cerebrospinal fluid (CSF) and serum could indicate why two closely related viruses exhibit different severity of their accompanied CNS inflammation.

Methods

Secretion patterns of 30 chemokines and 10 cytokines in CSF of adult patients with acute HSE (n = 14) and HSM (n = 20) in the initial stage of disease were analyzed and compared to control subjects without viral central nervous system infections and to levels in serum.

Results

Most measured chemokines and cytokines increased in CSF of HSE and HSM patients. Overall, the CSF chemokine levels were higher in CSF of HSM patients compared to HSE patients. However, only five chemokines reached levels in the CSF that exceeded those in serum facilitating a positive CSF-serum chemokine gradient. Of these, CXCL8, CXCL9, and CXCL10 were present at high levels both in HSE and HSM whereas CXCL11 and CCL8 were present in HSM alone. Several chemokines were also elevated in serum of HSE patients but only one in HSM patients. No chemokine in- or efflux between CSF and serum was indicated as the levels of chemokines in CSF and serum did not correlate.

Conclusions

We show that HSM is associated with a stronger and more diverse inflammatory response in the CNS compared to HSE in the initial stage of disease. The chemokine patterns were distinguished by the exclusive local CNS production of CXCL11 and CCL8 in HSM. Inflammation in HSM appears to be restricted to the CNS whereas HSE also was associated with systemic inflammation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0907-5) contains supplementary material, which is available to authorized users.

The role of some chemokines from the CXC subfamily in a mouse model of diabetic neuropathy

The mechanism involved in the development of diabetic neuropathy is complex. Currently, it is thought that chemokines play an important role in this process. The aim of this study was to determine how the level of some chemokines from the CXC subfamily varies in diabetic neuropathy and how the chemokines affect nociceptive transmission. A single intraperitoneal (i.p.) injection of streptozotocin (STZ; 200 mg/kg) resulted in an increased plasma glucose. The development of allodynia and hyperalgesia was measured at day 7 after STZ administration. Using Antibody Array techniques, the increases in CXCL1 (KC), CXCL5 (LIX), CXCL9 (MIG), and CXCL12 (SDF-1) protein levels were detected in STZ-injected mice. No changes in CXCL11 (I-TAC) or CXCL13 (BLC) protein levels were observed. The single intrathecal (i.t.) administration of CXCL1, CXCL5, CXCL9, and CXCL12 (each in doses of 10, 100, and 500 ng/5 μL) shows their pronociceptive properties as measured 1, 4, and 24 hours after injection using the tail-flick, von Frey, and cold plate tests. These findings indicate that the chemokines CXCL1, CXCL5, CXCL9, and CXCL12 are important in nociceptive transmission and may play a role in the development of diabetic neuropathy.

Distinct chemokine receptor axes regulate Th9 cell trafficking to allergic and autoimmune inflammatory sites

Migration of Th cells to peripheral sites of inflammation is essential for execution of their effector function. The recently described Th9 subset characteristically produces IL-9 and has been implicated in both allergy and autoimmunity. Despite this, the migratory properties of Th9 cells remain enigmatic. In this study, we examined chemokine receptor usage by Th9 cells and demonstrate, in models of allergy and autoimmunity, that these cells express functional CCR3, CCR6, and CXCR3, chemokine receptors commonly associated with other, functionally opposed effector Th subsets. Most Th9 cells that express CCR3 also express CXCR3 and CCR6, and expression of these receptors appears to account for the recruitment of Th9 cells to disparate inflammatory sites. During allergic inflammation, Th9 cells use CCR3 and CCR6, but not CXCR3, to home to the peritoneal cavity, whereas Th9 homing to the CNS during experimental autoimmune encephalomyelitis involves CXCR3 and CCR6 but not CCR3. To our knowledge, these data provide the first insights into regulation of Th9 cell trafficking in allergy and autoimmunity.

Pituitary adenylate cyclase activating peptide deficient mice exhibit impaired thymic and extrathymic regulatory T cell proliferation during EAE

We have shown that mice deficient in pituitary adenylate cyclase-activating polypeptide (PACAP, gene name ADCYAP1) manifest enhanced sensitivity to experimental autoimmune encephalomyelitis (EAE), supporting the anti-inflammatory actions described for this neuropeptide. In addition to an increased proinflammatory cytokine response in these mice, a reduction in regulatory T cell (Treg) abundance in the lymph nodes (LN) was observed, suggesting altered Treg kinetics. In the present study, we compared in PACAP deficient (KO) vs. wild type mice the abundances and rates of proliferation FoxP3⁺ Tregs in three sites, the LN, central nervous system (CNS) and thymus and the relative proportions of Th1, Th2, and Th17 effector subsets in the LN and CNS. Flow cytometry analyses revealed a decrease in Treg proliferation and an increased T effector/Tregs ratio in the LN and CNS of PACAP KO mice. In the thymus, the primary site of do novo natural Treg production, the total numbers and proliferative rates of FoxP3⁺ Tregs were significantly reduced. Moreover, the expression of IL-7, a cytokine implicated in thymic Treg expansion during EAE, failed to increase at the peak of the disease in the thymus and LN of PACAP KO mice. In addition to these Treg alterations, a specific reduction of Th2 cells (about 4-fold) was observed in the lymph nodes in PACAP KO mice, with no effects on Th1 and Th17 subsets, whereas in the CNS, Th1 and Th17 cells were increased and Th2 decreased. Our results suggest that endogenous production of the neuropeptide PACAP protects against EAE by modulating Treg expansion and Th subsets at multiple sites.

MS risk genes are transcriptionally regulated in CSF leukocytes at relapse

Background:

Infiltrating T-helper cells, cytotoxic T-cells, B-cells and monocytes are thought to mediate the damage to myelin, oligodendrocytes and axons in multiple sclerosis (MS), which results in progressive disability.

Objective:

The objective of this paper is to explore gene expression profiles of leukocytes in the cerebrospinal fluid (CSF) compartment of MS patients during relapse.

Methods:

Global gene expression was analyzed by DNA microarray analysis of cells in CSF from MS patients and controls, and verifications were performed with real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA).

Results:

Fifty percent of the recently described risk genes for MS and 28% of non-risk genes were differently expressed in MS patients compared to controls (χ2-test, p=7.7 × 10−5). Genes involved in T- and NK-cell processes were up-regulated, and genes involved in processes targeting innate immunity or B-cells were down-regulated in MS. Increased expression of EDN1 and CXCL11 and decreased expression of HMOX1 was verified with real-time PCR and increased expression of CXCL13 was verified with ELISA in CSF.

Conclusion:

DNA microarray analysis is useful in identifying differently expressed genes in CSF leukocytes, which may be important in MS in vivo. Our findings suggest that many of the risk genes for MS are differently expressed in the disease-mediating leukocytes that penetrate the blood-brain barrier.

Chemokines in CNS injury and repair

Recruitment of inflammatory cells is known to drive the secondary damage cascades that are common to injuries of the central nervous system (CNS). Cell activation and infiltration to the injury site is orchestrated by changes in the expression of chemokines, the chemoattractive cytokines. Reducing the numbers of recruited inflammatory cells by the blocking of the action of chemokines has turned out be a promising approach to diminish neuroinflammation and to improve tissue preservation and neovascularization. In addition, several chemokines have been shown to be essential for stem/progenitor cell attraction, their survival, differentiation and cytokine production. Thus, chemokines might indirectly participate in remyelination, neovascularization and neuroprotection, which are important prerequisites for CNS repair after trauma. Moreover, CXCL12 promotes neurite outgrowth in the presence of growth inhibitory CNS myelin and enhances axonal sprouting after spinal cord injury (SCI). Here, we review current knowledge about the exciting functions of chemokines in CNS trauma, including SCI, traumatic brain injury and stroke. We identify common principles of chemokine action and discuss the potentials and challenges of therapeutic interventions with chemokines.

Integrating individual functional moieties of CXCL10 and CXCL11 into a novel chimeric chemokine leads to synergistic antitumor effects: a strategy for chemokine-based multi-target-directed cancer therapy

The complexity of tumor biology necessitates a multimodality approach that targets different aspects of tumor environment in order to generate the greatest benefit. IFN-inducible T cell alpha chemoattractant (ITAC)/CXCL11 and IFN-inducible protein 10 (IP10)/CXCL10 could exert antitumor effects with functional specificity and thus emerge as attractive candidates for combinatorial strategy. Disappointedly, a synergistic antitumor effect could not be observed when CXCL10 and CXCL11 were pooled together. In this regard, we seek to improve antitumor efficacy by integrating their individual functional moieties into a chemokine chimeric molecule, designated ITIP, which was engineered by substituting the N-terminal and N-loop region of CXCL10 with those of CXCL11. The functional properties of ITIP were determined by chemotaxis and angiogenesis assays. The antitumor efficacy was tested in murine CT26 colon carcinoma, 4T1 mammary carcinoma and 3LL lung carcinoma. Here we showed that ITIP not only exhibited respective functional superiority but strikingly promoted regression of established tumors and remarkably prolonged survival of mice compared with its parent chemokines, either alone or in combination. The chemokine chimera induced an augmented anti-tumor immunity and a marked decrease in tumor vasculature. Antibody neutralization studies indicated that CXCL10 and CXCL11 moieties of ITIP were responsible for anti-angiogenesis and chemotaxis in antitumor response, respectively. These results indicated that integrating individual functional moieties of CXCL10 and CXCL11 into a chimeric chemokine could lead to a synergistic antitumor effect. Thus, this integration strategy holds promise for chemokine-based multiple targeted therapy of cancer.

Inhibition of CCR6 function reduces the severity of experimental autoimmune encephalomyelitis via effects on the priming phase of the immune response

Chemokines are essential for homeostasis and activation of the immune system. The chemokine ligand/receptor pairing CCL20/CCR6 is interesting because these molecules display characteristics of both homeostatic and activation functions. These dual characteristics suggest a role for CCR6 in the priming and effector phases of the immune response. However, while CCR6 has been implicated in the effector phase in several models, a role in the priming phase is less clear. Herein we analyze the role of CCR6 in these two important arms of the immune response during experimental autoimmune encephalomyelitis (EAE). Both CCR6 and its chemokine ligand CCL20 were up-regulated in the draining lymph nodes and spinal cord during EAE, and CCR6 was up-regulated on CD4(+) T cells that had divided following induction of EAE. The functional role of this expression was demonstrated by impaired development of EAE in gene-targeted CCR6-deficient mice and in mice treated either with a neutralizing anti-CCR6 Ab or with a novel receptor antagonist. Inhibition of EAE was due to reduced priming of autoreactive CD4(+) T cells probably as a result of impaired late-stage influx of dendritic cells into draining lymph nodes. This was accompanied by reduced egress of activated lymphocytes from the lymph nodes. These results demonstrate a novel role for CCR6 in the mechanism of autoreactive lymphocyte priming and emigration to the efferent lymphatics.

Neural stem cells in the mammalian brain

New fundamental results on stem cell biology have been obtained in the past 15 years. These results allow us to reinterpret the functioning of the cerebral tissue in health and disease. Proliferating stem cells have been found in the adult brain, which can be involved in postinjury repair and can replace dead cells under specific conditions. Numerous genomic mechanisms controlling stem cell proliferation and differentiation have been identified. The involvement of stem cells in the genesis of malignant tumors has been demonstrated. Neural stem cell tropism toward tumors has been shown. These findings suggest new lines of research on brain functioning and development. Stem cells can be used to develop radically new treatments of neurodegenerative and cancer diseases of the brain.

Induction of the genes for Cxcl9 and Cxcl10 is dependent on IFN-gamma but shows differential cellular expression in experimental autoimmune encephalomyelitis and by astrocytes and microglia in vitro

The chemokines CXCL9 and CXCL10 bind to the common receptor CXCR3 and are implicated in the pathogenesis of T-cell-mediated immunity in the central nervous system (CNS). Here we examined the temporal and spatial regulation of the Cxcl9 and Cxcl10 genes in the CNS of mice with myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) and by glial cells in vitro. During peak disease the levels of CXCL9 and CXCL10 mRNA and protein were increased significantly in the cerebellum and spinal cord but were reduced during the recovery phase. Expression of these genes in the CNS was abolished in IFN-gamma-receptor deficient mice with MOG-EAE. In wild-type mice, CXCL9 RNA was localized mainly to infiltrating mononuclear cells including lesion and perilesional microglia, while CXCL10 RNA was seen primarily in more distal astrocytes that surrounded the inflammatory lesions. Examination of cultured glia following treatment with IFN-gamma revealed that while both CXCL9 and CXCL10 mRNA transcripts were induced in microglia, only CXCL10 mRNA was induced in astrocytes. Thus, although IFN-gamma is the pivotal mediator of both Cxcl10 and Cxcl9 gene expression in EAE, this cytokine differentially regulates the expression of these genes by astrocytes and microglia. The differential glial localization of these chemokines in EAE suggests CXCL9 and CXCL10 have specialized functions.

CXCR3 signaling reduces the severity of experimental autoimmune encephalomyelitis by controlling the parenchymal distribution of effector and regulatory T cells in the central nervous system

The chemokine receptor CXCR3 promotes the trafficking of activated T and NK cells in response to three ligands, CXCL9, CXCL10, and CXCL11. Although these chemokines are produced in the CNS in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), their role in the pathogenesis of CNS autoimmunity is unresolved. We examined the function of CXCR3 signaling in EAE using mice that were deficient for CXCR3 (CXCR3(-/-)). The time to onset and peak disease severity were similar for CXCR3(-/-) and wild-type (WT) animals; however, CXCR3(-/-) mice had more severe chronic disease with increased demyelination and axonal damage. The inflammatory lesions in WT mice consisted of well-demarcated perivascular mononuclear cell infiltrates, mainly in the spinal cord and cerebellum. In CXCR3(-/-) mice, these lesions were more widespread throughout the CNS and were diffused and poorly organized, with T cells and highly activated microglia/macrophages scattered throughout the white matter. Although the number of CD4(+) and CD8(+) T cells infiltrating the CNS were similar in CXCR3(-/-) and WT mice, Foxp3(+) regulatory T cells were significantly reduced in number and dispersed in CXCR3(-/-) mice. The expression of various chemokine and cytokine genes in the CNS was similar in CXCR3(-/-) and WT mice. The genes for the CXCR3 ligands were expressed predominantly in and/or immediately surrounding the mononuclear cell infiltrates. We conclude that in EAE, CXCR3 signaling constrains T cells to the perivascular space in the CNS and augments regulatory T cell recruitment and effector T cell interaction, thus limiting autoimmune-mediated tissue damage.

Altered chemokine profile associated with exacerbated autoimmune pathology under conditions of genetic interferon-gamma deficiency

PURPOSE

A prior study showed that mice deficient in IFN-gamma (GKO) are more susceptible to experimental autoimmune uveitis (EAU) than are wild-type (WT) mice. Histopathology of uveitic eyes revealed that the ocular infiltrate in GKO mice was dominated by neutrophils and eosinophils rather than by mononuclear cells, as in WT mice. The present study was conducted to explore the differential expression of chemokine(s) likely to account for the distinct inflammatory cell composition in uveitic eyes of WT and GKO mice.

METHODS

Mice were immunized to induce EAU. Lymph nodes draining the site of the immunization and the eyes were collected at different time points for chemokine analysis. Microarray, real-time PCR and protein analyses were performed to examine the expression of chemokines in WT and GKO mice.

RESULTS

Many chemokines were differentially upregulated in GKO versus WT mice. Expression of the Th1-associated chemokines CXCL10, CXCL9, CCL5, and CXCL11 was elevated in WT mice, whereas the Th2-associated chemokines CCL11, CCL17, and CCL1 and the Th17-associated chemokines CCL22 and CXCL2 were elevated in the GKO mice. Depletion of granulocytes abrogated EAU in both WT and GKO mice.

CONCLUSIONS

These results suggest that Th1-associated chemokines play a critical role in the attraction of mononuclear cells to the eyes in the presence of IFN-gamma, while in the absence of this cytokine, Th2- and Th17-related chemokines may be the key elements for influx of granulocytes.

In situ expression of IFN-gamma-inducible T cell alpha chemoattractant in breast cancer mounts an enhanced specific anti-tumor immunity which leads to tumor regression

Increased evidence indicates that chemokines are involved in tumor growth. ITAC, a key member of chemokines, possesses the ability to recruit T cells and enhance immune responses. Therefore, ITAC might contribute to antitumor immunity. In this study, we evaluated the relationship between the expression of ITAC and human breast cancer advancement. We further investigated whether forced expression of ITAC in tumor sites could mediate enhanced antitumor immunity in a murine breast cancer model. Results showed that ITAC expression level was down-regulated in 31 breast cancer specimens compared to normal mammary tissues, and associated negatively with the stages of breast cancer. Contrarily, forced expression of ITAC in murine 4T1 tumor cells resulted in tumor regression after initial growth upon injection into naïve Balb/c mice. More lymphocytes were recruited to the site of tumor inoculated by 4T1-ITAC and more than 80% of these T cells expressed the ITAC receptor, CXCR3. ITAC-recruited TILs exhibited 4T1-specific proliferation and cytotoxicity, and an increased IFN-gamma but decreased IL-4 production. Importantly, forced expression of ITAC in 4T1 tumor nodules inhibited tumor growth. These findings demonstrated that the decreased expression of ITAC is associated with the advancement of breast cancer in patients. Forced expression of ITAC in tumor site not only induces increased T cell-recruitment and elicits a specific antitumor immunity, but also mediates regression of established 4T1 tumors, indicating the potential application of ITAC-expressing tumor cells in cancer immunotherapy and vaccine designing.

Expression of the CXC chemokine receptor 3 and its ligands in the livers of ischemia/reperfusion injured rats

AIM: To explore the expression of the CXC chemokine receptor 3 (CXCR3) and its ligands (IP-10, Mig) in the livers of ischemia/reperfusion (I/R) injured rats.

METHODS: Thirty-two Wistar rats were randomly divided into four groups, with 8 rats in each group: sham operation (SO) and 6-, 12- and 24-hour I/R groups. The level of tumor necrosis factor (TNF)-α in liver tissue was measured by enzyme-linked immunosorbent assay (ELISA). The expression levels of CXCR3 and its ligands (IP-10, Mig) were assessed by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). The serum levels of alanine transaminase (ALT) and aspartate transaminase (AST) were also analyzed.

RESULTS: Low expression levels of CXCR3, IP-10 and Mig mRNAs were observed in the SO group. The expression levels of CXCR3 and IP-10 mRNAs in the ischemic tissues of I/R animals were significantly higher than those in SO animals (CXCR3: 0.925 ± 0.109, 0.786 ± 0.074, 0.606 ± 0.082 vs 0.125 ± 0.028, all P < 0.01; IP-10: 0.863 ± 0.091, 0.680 ± 0.075, 0.543 ± 0.284 vs 0.128 ± 0.027, all P < 0.01). The expression levels of CXCR3 and IP-10 mRNAs in the ischemia tissues of 6-hour I/R animals were higher than those in the ischemic tissues of 12-hour I/R animals (P < 0.01). There was no difference in the level of Mig mRNA between the I/R group and the SO group. Compared with the SO group, the level of TNF-α was significantly increased in the I/R groups (154.88 ± 14.35 ng/L, 258.88 ± 13.73 ng/L, 182.87 ± 10.95 ng/L vs 23.63 ± 4.00 ng/L, all P < 0.01), reaching a peak at 12 h after reperfusion.

CONCLUSION: The expression levels of mRNAs for CXCR3 and its ligand IP-10 are rapidly up-regulated in liver ischemia/reperfusion tissue, suggesting that CXCR3 plays an important role in liver injury induced by I/R.

Ingested (oral) SIRS peptide 1–21 inhibits acute EAE by inducing Th2-like cytokines

OBJECTIVE

Ingested type I IFN inhibits clinical attacks, relapses and inflammation in murine chronic relapsing EAE by inhibiting Th1-like cytokines. Type I IFN activates human suppressor T cells that produce SIRS.

METHODS

We examined whether oral (ingested) SIRS peptide inhibits EAE by decreasing Th1-like cytokines.

RESULTS

Parenteral SIRS peptide 1-21 showed a significant inhibition of disease severity in murine EAE. Ingested SIRS peptide at 10 and 100 microg SIRS peptide showed a significant inhibition of disease severity but also a prolonged delay in the onset of disease compared to placebo. There were significantly less inflammatory foci in the SIRS peptide fed group compared to the control mock fed group. Splenocytes from SIRS peptide 1-21 fed mice showed increased production of Th2-like CD30L, IL-13, TCA-3 cytokines/chemokines and decreased production of Th1-like cytokine lymphotactin.

INTERPRETATION

Ingested (oral) SIRS peptide significantly inhibits both clinical EAE and inflammation predominately via counter-regulatory type 2-like cytokines/chemokines IL-13, CD30L and TCA-3.

Rat chemokine CXCL11: structure, tissue distribution, function and expression in cardiac transplantation models

CXCL11 is thought to play a critical role in allograft rejection. To clarify the role of CXCL11 in the rat transplantation model, we cloned CXCL11 cDNA from rat liver tissue and used it to study CXCL11 structure, function and expression. The rat CXCL11 gene encodes a protein of 100 amino acids and spans approximately a 2.8 kb DNA segment containing 4 exons in the protein coding region. Tissue distribution of rat CXCL11 was analyzed by quantitative RT-PCR and showed that rat CXCL11 mRNA is expressed in various tissues and, in particular, at high levels in the spleen and lymph nodes. COS-1 cells were transfected with a plasmid vector encoding rat CXCL11 and used to study CXCL11 effects on cell migration and internalization of CXCR3, the CXCL11 receptor. The recombinant CXCL11 showed chemotactic properties and induced CXCR3 internalization in CD4(+) T cells. Expression of CXCL11 mRNA also was measured in rat acute (ACI to LEW) and chronic (LEW to F344) heart transplant rejection models. CXCL11 mRNA expression in allografts increased in both models, compared with controls, and was primarily observed in infiltrating macrophages and donor endothelial cells. These results indicate that, like the other CXCR3 chemokines, rat CXCL11 seems to have a role in the homing of CD4(+) T cells in both acute and chronic rejection models of heart allotransplantation.

CXCL10 is the key ligand for CXCR3 on CD8+ effector T cells involved in immune surveillance of the lymphocytic choriomeningitis virus-infected central nervous system

IFN-gamma-inducible protein 10/CXCL10 is a chemokine associated with type 1 T cell responses, regulating the migration of activated T cells through binding to the CXCR3 receptor. Expression of both CXCL10 and CXCR3 are observed during immunopathological diseases of the CNS, and this receptor/ligand pair is thought to play a central role in regulating T cell-mediated inflammation in this organ site. In this report, we investigated the role of CXCL10 in regulating CD8(+) T cell-mediated inflammation in the virus-infected brain. This was done through analysis of CXCL10-deficient mice infected intracerebrally with lymphocytic choriomeningitis virus, which in normal immunocompetent mice induces a fatal CD8(+) T cell-mediated meningoencephalitis. We found that a normal antiviral CD8(+) T cell response was generated in CXCL10-deficient mice, and that lack of CXCL10 had no influence on the accumulation of mononuclear cells in the cerebrospinal fluid. However, analysis of the susceptibility of CXCL10-deficient mice to lymphocytic choriomeningitis virus-induced meningitis revealed that these mice just like CXCR3-deficient mice were partially resistant to this disease, whereas wild-type mice invariably died. Furthermore, despite marked up-regulation of the two remaining CXCR3 ligands: CXCL9 and 11, we found a reduced accumulation of CD8(+) T cells in the brain parenchyma around the time point when wild-type mice succumb as a result of CD8(+) T cell-mediated inflammation. Thus, taken together these results indicate a central role for CXCL10 in regulating the accumulation of effector T cells at sites of CNS inflammation, with no apparent compensatory effect of other CXCR3 ligands.

Vaccination with IFN-inducible T cell alpha chemoattractant (ITAC) gene-modified tumor cell attenuates disseminated metastases of circulating tumor cells

Immunotherapeutic strategies for metastatic diseases are being developed. IFN-inducible T cell alpha chemoattractant (ITAC) has been demonstrated to be able to induce Th1-type immune response. However, the effects of ITAC on the tumor metastasis have not been fully understood. In the present study, the ITAC-modified tumor cell vaccine in inhibiting the disseminated pulmonary metastasis was evaluated. ITAC-modified tumor cell vaccine 4T1-ITAC was developed by stably transfecting 4T1 cells with pcDNA3-ITAC plasmid. Mice were vaccinated with 4T1-ITAC. Mice vaccinated with 4T1-pcDNA3 and 4T1 were used as controls. Specific cellular immune responses against 4T1 were tested by in vitro proliferation, cytokine production and cytotoxic assay. The number of clonogenic metastatic tumor cells and metastatic forci on the surface of lung were counted by histological examination. Results showed that a significant enhancement of proliferative and cytotoxic activities accompanied with increased IFN-gamma and TNF-alpha production as well as decreased IL-4 production were obtained from the mice vaccinated with 4T1-ITAC. The number of clonogenic metastatic tumor cells in the mice vaccinated with 4T1-ITAC cells reduced markedly and no visible metastasis was found in the lungs of the 4T1-ITAC vaccinated mice. Consequently, the survival rate was dramatically increased in these mice. Taken together, our results demonstrated that ITAC-modified tumor cell vaccine can enhance the anti-tumor immunity and reduce the incidence of disseminated metastasis.