β2-adrenergic agonists modulate TNF-α induced astrocytic inflammatory gene expression and brain inflammatory cell populations

Background: The NF-kappa B signaling pathway orchestrates many of the intricate aspects of neuroinflammation. Astrocytic beta(2)-adrenergic receptors have emerged as potential regulators in central nervous system inflammation and are potential targets for pharmacological modulation. The aim of this study was to elucidate the crosstalk between astrocytic beta(2)-adrenergic receptors and the TNF-alpha induced inflammatory gene program. Methods: Proinflammatory conditions were generated by the administration of TNF-alpha. Genes that are susceptible to astrocytic crosstalk between beta(2)-adrenergic receptors (stimulated by clenbuterol) and TNF-alpha were identified by qPCR-macroarray-based gene expression analysis in a human 1321 N1 astrocytoma cell line. Transcriptional patterns of the identified genes in vitro were validated by RT-PCR on the 1321 N1 cell line as well as on primary rat astrocytes. In vivo expression patterns were examined by intracerebroventricular administration of clenbuterol and/or TNF-alpha in rats. To examine the impact on the inflammatory cell content of the brain we performed extensive FACS analysis of rat brain immune cells after intracerebroventricular clenbuterol and/or TNF-alpha administration. Results: Parallel transcriptional patterns in vivo and in vitro confirmed the relevance of astrocytic beta(2)-adrenergic receptors as modulators of brain inflammatory responses. Importantly, we observed pronounced effects of beta(2)-adrenergic receptor agonists and TNF-alpha on IL-6, CXCL2, CXCL3, VCAM1, and ICAM1 expression, suggesting a role in inflammatory brain cell homeostasis. Extensive FACS-analysis of inflammatory cell content in the brain demonstrated that clenbuterol/TNF-alpha co-administration skewed the T cell population towards a double negative phenotype and induced a shift in the myeloid brain cell population towards a neutrophilic predominance. Conclusions: Our results show that astrocytic beta(2)-adrenergic receptors are potent regulators of astrocytic TNF-alpha-activated genes in vitro and in vivo, and ultimately modulate the molecular network involved in the homeostasis of inflammatory cells in the central nervous system. Astrocytic beta(2)-adrenergic receptors and their downstream signaling pathway may serve as potential targets to modulate neuroinflammatory responses

Neuroprotection by Insulin-like Growth Factor-1 in Rats with Ischemic Stroke is Associated with Microglial Changes and a Reduction in Neuroinflammation

We and others have shown that insulin-like growth factor-1 (IGF-1) is neuroprotective when administered systemically shortly following stroke. In the current study, we addressed the hypothesis that microglia mediate neuroprotection by IGF-1 following ischemic stroke. Furthermore, we investigated whether IGF-1 modulates pro- and anti-inflammatory mediators in ischemic brain with a special reference to microglia. Ischemic stroke was induced in normal conscious Wistar rats by infusing the vasoconstrictor, endothelin-1 (Et-1), next to middle cerebral artery (MCA). IGF-1 (300 μg) was injected subcutaneously (SC) at 30 and 120 min following stroke. Microglial inhibitor, minocycline, was injected intraperitoneally (IP) at 1 h before stroke (25 mg/kg) and 11 h after stroke (45 mg/kg). Post-stroke IGF-1 treatment reduced the infarct size and increased the sensorimotor function which coincided with an increase in the number of ameboid microglia in the ischemic cortex. Minocycline treatment abrogated the increase in ameboid microglia by IGF-1, while the effect of IGF-1 in the reduction of infarct size was only partially affected. IGF-1 suppressed mRNA expression of inducible nitric oxide synthase (iNOS) and interleukin (IL)-1β in the ischemic hemisphere, while in purified microglia, only iNOS expression levels were reduced. Our findings show that microglia are a target for IGF-1 and that neuroprotection by IGF-1 coincides with down-regulation of inflammatory mediators which could be instrumental to the beneficial effects

Mycophenolate mofetil inhibits the development of Coxsackie B3-virus-induced myocarditis in mice

BACKGROUND: Viral replication as well as an immunopathological component are assumed to be involved in the development of coxsackie B virus (CBV)-induced myocarditis. We observed that mycophenolic acid (MPA), the active metabolite of the immunosuppressive agent mycophenolate mofetil (MMF), inhibits coxsackie B3 virus (CBV3) replication in primary Human myocardial fibroblasts. We therefore studied whether MMF, which is thus endowed with a direct antiviral as well as immunosuppressive effect, may prevent CBV-induced myocarditis in a murine model. RESULTS: Four week old C3H-mice were infected with CBV3 and received twice daily, for 7 consecutive days (from one day before to 5 days post-virus inoculation) treatment with MMF via oral gavage. Treatment with MMF resulted in a significant reduction in the development of CBV-induced myocarditis as assessed by morphometric analysis, i.e. 78% reduction when MMF was administered at 300 mg/kg/day (p < 0.001), 65% reduction at 200 mg/kg/day (p < 0.001), and 52% reduction at 100 mg/kg/day (p = 0.001). The beneficial effect could not be ascribed to inhibition of viral replication since titers of infectious virus and viral RNA in heart tissue were increased in MMF-treated animals as compared to untreated animals. CONCLUSION: The immunosuppressive agent MMF results in an important reduction of CBV3-induced myocarditis in a murine model

IHIVARNA phase IIa, a randomized, placebo-controlled, double-blinded trial to evaluate the safety and immunogenicity of iHIVARNA-01 in chronically HIV-infected patients under stable combined antiretroviral therapy

Background: HIV therapeutic vaccination aims to improve the immune responses against HIV in order to control viral replication without the need for combined antiretroviral therapy (cART). iHIVARNA-01 is a novel vaccine combining mRNA delivery and T-cell immunogen (HTI) based on conserved targets of effective antiviral T-cell responses. In addition, it holds adequate stimuli required for activating antigen presenting cells (APC)s and co-activating specific T-cells (TriMix), including human CD40L, constitutively active TLR4 (caTLR4) and CD70. We propose that in-vivo targeting of dendritic cells (DCs) by direct administration of a HIV mRNA encoding these immune modulating proteins might be an attractive alternative to target DCs in vitro. Methods/design: This is a phase-IIa, randomized, double-blinded, placebo-controlled, multicenter study in chronically HIV-1 infected patients under stable cART. One of the three study arms is randomly allocated to subjects. Three vaccinations with either HIVACAT T-cell immunogen (HTI)-TriMix (iHIVARNA-01), TriMix or water for injection (WFI) (weeks 0, 2 and 4) are administered by intranodal injection in the inguinal region. Two weeks after the last immunization (week 6) cART is stopped for 12 weeks. The two primary endpoints are: (1) safety and tolerability of intranodal iHIVARNA-01 vaccination compared with TriMix or WFI and (2) induced immunogenicity, i.e., increase in the frequency of HIV-specific T-cell responses between baseline, week 6 and 12 weeks after treatment interruption in iHIVARNA-01-treated patients as compared to the control groups, immunized with TriMix

Oncolytic virus-induced cell death and immunity: a match made in heaven?

Our understanding of the mechanisms responsible for cancer development has increased enormously over the last decades. However, for many cancers, this has not been translated into a significant improvement in overall survival, and overall mortality remains high. Treatment for many malignancies remains based on surgery, chemotherapy, and radiotherapy. Significant progress has been made toward the development of more specific, more potent, and less invasive treatment modalities, but such targeted therapies remain the exception for most cancers. Thus, cancer therapies based on a different mechanism of action should be explored. The immune system plays an important role in keeping tumor growth at bay. However, in many cases, these responses are not strong enough to keep tumor growth under control. Thus, immunotherapy aims to boost the immune system to suppress tumor growth efficiently. This has been demonstrated by the recent successes of immune checkpoint therapy in several cancers. Oncolytic viruses (OVs) are another exciting class of immunotherapy agent. As well as replicating selectively within and killing tumor cells, OVs are able to elicit potent anti-tumor immune responses. Therapeutic vaccination with OVs, also referred to as cancer virotherapy, can thus be tailored to elicit vigorous cellular immune responses and even target individual malignancies in a personalized manner. In this review, we will describe the intricate link among oncolytic virotherapy, tumor immunology, and immunogenic cell death (ICD) and discuss ways to harness optimally their potential for future cancer therapy

Attenuated Expression of A20 Markedly Increases the Efficacy of Double-Stranded RNA-Activated Dendritic Cells As an Anti-Cancer Vaccine

A20 is a zinc finger protein with ubiquitin-modifying activity. A20 has been described as negatively regulating signaling induced by the TNF receptor and TLR family in a number of cell types, including mouse bone marrow-derived dendritic cells (DiCs). However, the expression and effect of A20 in activated human monocyte-derived DCs have not been previously evaluated. We report that DCs activated with the TLR3 ligand poly(I:C) up-regulate A20. Down-regulating A20 demonstrated its role in the functional activation of DCs. A20 down-regulated DCs showed higher activation of the transcription factors NF-kappa B and activator protein-1, which resulted in increased and sustained production of IL-6, IL-10, and IL-12p70. We additionally silenced the immunosuppressive cytokine IL-10 and demonstrated that IL-10 inhibits T cell proliferation. We further demonstrated that A20 down-regulated DCs skew naive CD4(+) T cells toward IFN-gamma producing Th1 cells, a process which is dependent on IL-12p70 and which is unaffected by IL-10. Furthermore, A20 and/or IL-10 down-regulated DCs had an enhanced capacity to prime Melan-A/MART-1 specific CD8(+) T cells. Finally, we demonstrated that potent T cell stimulatory DCs are generated by the simultaneous delivery of poly(I:C12U), A20, or A20/IL-10 small interfering RNA and Ag-encoding mRNA, introducing a one step approach to improve DC-based vaccines. Together these findings demonstrate that A20 negatively regulates NF-kappa B and activator protein-1 in DCs and that down-regulation of A20 results in DCs with enhanced T cell stimulatory capacity