High interleukin-10 expression within the central nervous system may be important for initiation of recovery of Dark Agouti rats from experimental autoimmune encephalomyelitis.

Dark Agouti (DA) rats are highly susceptible to induction of experimental autoimmune encephalomyelitis (EAE), still they completely recover from the disease. Here, we were interested to determine contribution of major anti-inflammatory cytokines transforming growth factor (TGF)-β and interleukin (IL)-10 to the recovery of DA rats from EAE. To that extent we determined CNS expression of these cytokines in DA rats at different phases of EAE and compared data to those obtained in EAE-resistant Albino Oxford (AO) rats. Higher expression of TGF-β was persistently observed in the CNS of AO rats, even if rats were not immunized. This implied that high TGF-β within the CNS is important for resistance of AO rats to EAE induction. On the contrary, IL-10 expression was consistently higher in DA than in AO rats and it culminated at the peak of EAE. Methylprednisolone suppressed EAE and expression of IL-10 in spinal cord homogenates, while IL-10 was increased in CNS-infiltrating immune cells. This implied that IL-10 might have a significant role in recovery of DA rats from the disease. Thus, we next explored effects of IL-10 on astrocytes, glial cells that largely contribute to control of CNS inflammation. IL-10 stimulated astrocytic expression of an important regulator of neuroinflammation, CXCL12. Thus, IL-10 might contribute to recovery of DA rats from EAE through induction of CXCL12 expression in astrocytes.

Blaževski J ，Petković F ，Momčilović M ，Jevtic B ，Miljković D ，Mostarica Stojković M ... -  《-》

CXCL12 expression within the CNS contributes to the resistance against experimental autoimmune encephalomyelitis in Albino Oxford rats.

Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis, a chronic inflammatory and demyelinating disease of the CNS. Albino Oxford (AO) rats are resistant to the induction of EAE, while the disease can be readily induced in Dark Agouti (DA) rats. Here we investigated a potential contribution of the CNS milieu in the limitation of the encephalitogenic autoimmune response. EAE was induced by immunization of the respective rat strains with spinal cord homogenate emulsified in complete Freund's adjuvant. AO rats did not exhibit clinical signs after immunization while DA rats developed severe neurologic deficits. Infiltration of immune cells into spinal cords (SC) was evident in both strains 12-14 days after the immunization. EAE lesions of AO rats contained substantially lower numbers of CD4+ T cells and CD11b+ cells compared to those in DA rats. This went together with lower levels of interferon (IFN)-γ and interleukin (IL)-17 in the cells isolated from SC. We found a dramatic increase of CXCL12 expression in SC tissue and microvessels of AO rats, whereas DA rats markedly decreased the expression of this chemokine within their CNS. Administration of the CXCL12 antagonist AMD3100 to a substrain of AO rats that developed a weak EAE led to earlier onset and exacerbation of the disease. These results suggest a role of CXCL12 in down-regulating autoimmune processes in AO rats during EAE. Therapeutic modulation of CXCL12 could be a promising strategy for the treatment of CNS autoimmunity.

Miljković D ，Stanojević Z ，Momcilović M ，Odoardi F ，Flügel A ，Mostarica-Stojković M ... -  《-》

CXCL12-γ expression is inhibited in neuroinflammation.

CXCL12 plays a protective role in CNS autoimmunity. Expression of CXCL12-γ, which has distinct structural and functional properties than the other isoforms of CXCL12, was determined in spinal cords of rats immunized to develop experimental autoimmune encephalomyelitis (EAE). CNS expression of CXCL12-γ was markedly lower in EAE-prone Dark Agouti rats than in EAE-resistant Albino Oxford rats, both in spinal cord homogenates and micro-blood vessels isolated from spinal cords. Inhibition of nitric oxide (NO) synthesis in DA rats upregulated, while donation of NO in AO rats downregulated CNS expression of CXCL12-γ. NO inhibited CXCL12-γ expression in astrocytes in vitro. A splice variant of CXCL12-γ which migrates into nucleolus was not detected in spinal cord or astrocytes. Thus, CXCL12-γ is expressed in the CNS after EAE induction, but its expression is markedly suppressed in spinal cord affected with full blown inflammation. NO is an important regulator of CXCL12-γ expression in neuroinflammation.

Timotijević G ，Petković F ，Blaževski J ，Momčilović M ，Mostarica Stojković M ，Miljković D ... -  《-》

Strain difference in susceptibility to experimental autoimmune encephalomyelitis between Albino Oxford and Dark Agouti rats correlates with disparity in production of IL-17, but not nitric oxide.

Miljkovic D ，Stosic-Grujicic S ，Markovic M ，Momcilovic M ，Ramic Z ，Maksimovic-Ivanic D ，Mijatovic S ，Popadic D ，Cvetkovic I ，Mostarica-Stojkovic M ... -  《-》

T cell-depleted splenocytes from mice pre-immunized with neuroantigen in incomplete Freund's adjuvant involved in protection from experimental autoimmune encephalomyelitis.

Mice immunized with neuroantigens in incomplete Freund's adjuvant (IFA) are resistant to subsequent induction of experimental autoimmune encephalomyelitis (EAE). The mechanisms involved in this protection are complex. Studies on relevant CD4(+) or CD8(+) T cells, including effective and regulatory T cells, have been performed by others. In this work, the effects of CD4(-)-, CD8(-)- splenocytes on protection from EAE in C57BL/6 mice which were immunized with myelin oligodendrocyte glycoprotein 35-55 (MOG)35-55 in IFA were evaluated. We observed that MOG-reactive CD4(+) T cells failed to be activated and proliferate when CD4(-)-, CD8(-)- splenocytes from MOG/IFA-immunized mice were regarded as antigen-presenting cells (APC). It was shown that these APC expressed lower levels of major histocompatibility complex class II (MHC-II), CD80, and CD86 than naïve cells. In addition, CD4(-)-, CD8(-)- splenocytes from MOG/IFA-immunized mice showed significantly higher levels of IL-10 mRNA expression. When the immunized-mice were induced to develop EAE, these cells secreted significantly higher levels of IL-10 and produced lower levels of IL-6, leading to decreased secretion of IL-17 and IFN-γ from MOG-specific CD4(+) T cells. The transfer of CD4(-)-, CD8(-)- splenocytes from MOG/IFA-immunized mice was able to ameliorate the subsequent induction of EAE in recipient mice. Thus, MOG/IFA immunization can modulate CD4(-)-, CD8(-)- splenocytes by reducing the expression of antigen-presenting molecules and altering the levels of secreted cytokines. Our study reveals an additional mechanism involved in the protective effects of MOG/IFA pre-immunization in an EAE model.

Zheng H ，Zhang H ，Liu F ，Qi Y ，Jiang H ... -  《-》