Experimental Autoimmune Encephalomyelitis Is Successfully Controlled by Epicutaneous Administration of MOG Plus Vitamin D Analog

Abstract

Multiple sclerosis (MS) is an inflammatory and demyelinating disorder of the central nervous system (CNS). Experimental autoimmune encephalomyelitis (EAE) has been widely employed to evaluate new strategies to control MS, including procedures to induce immunological tolerance. Considering that skin exposure to protein antigens can induce tolerance and that vitamin D analogs conserve immunomodulatory potential and are less toxic, we investigated the efficacy of epicutaneous application of a myelin oligodendrocyte glycoprotein peptide (MOG35–55) associated with paricalcitol (PARI) on EAE development. Three and 11 days after EAE induction, C57BL/6 mice were treated with an occlusive patch containing MOG plus PARI. Clinical parameters were daily assessed, whereas immunological and histological evaluations were performed during the acute EAE phase. MOG and MOG + PARI significantly controlled disease development reducing weight loss and clinical score. Moreover, MOG and MOG + PARI reduced the inflammatory process and preserved the myelin sheath in the CNS. High percentages of Foxp3+ regulatory T cells (Tregs) and lower MHCII fluorescence intensity in dendritic cells in draining lymph nodes were concomitantly observed. MOG + PARI association was, however, more efficient being able to reduce disease incidence and clinical scores more significantly than MOG or PARI alone. This experimental group also displayed a higher ratio between mRNA expression for Foxp3 and RORc and a higher percentage of Foxp3+ cells in the CNS. Modulation of activation markers observed in microglial cells eluted from EAE treated mice were confirmed by in vitro studies with the BV-2 microglial cell line. The results show that MOG + PARI association applied by an epicutaneous route controlled EAE development. Protective involved mechanisms include mainly a higher proportion of Tregs and also a direct immunomodulatory effect of PARI on microglial cells.

Calcitriol Prevents Neuroinflammation and Reduces Blood-Brain Barrier Disruption and Local Macrophage/Microglia Activation

“…Two of the most studied innate cell populations involved in ROS-mediated tissue damage in MS are infiltrating macrophages and resident microglia (Chu et al, 2018). Interestingly, these two cell types expressed much lower levels of MHCII in 1,25-VitD3-treated mice, suggesting that they were less activated, which has previously been described by other authors (Kong et al, 2016;Zorzella-Pezavento et al, 2017). This decreased MHCII level is likely relevant for protection since the degree of recognition, proliferation, and activation of selfreactive T cells is highly dependent on the presentation of selfpeptides by these APCs (Almolda et al, 2011).…”

“…Inguinal lymph node cells were obtained and adjusted to 2.5x10 5 cells/ml and then cultured in complete RPMI medium (RPMI supplemented with 10% of fetal calf serum and 2 mM of glutamine). Cultures were incubated during 48 h in the presence of MOG (20 mg/ml), as previously described by Zorzella-Pezavento et al (2017). Cytokine levels were then quantified by enzyme-linked immunosorbent assay (ELISA) in culture supernatants using IFN-g BD OptEIA Sets (BD Biosciences, San Diego, CA, USA) and interleukin (IL)-6, TNF-a, and IL-17 DuoSets (R&D Systems, Minneapolis, MN, USA).…”

Calming Down Mast Cells with Ketotifen: A Potential Strategy for Multiple Sclerosis Therapy?

“…Pezavento et al [54]. These animals also received two intraperitoneal doses, 0 and 48 hours after immunization, of 200 ng of Bordetella pertussis toxin (Sigma-Aldrich).…”

Preclinical Therapy with Vitamin D3 in Experimental Encephalomyelitis: Efficacy and Comparison with Paricalcitol

“…We also tested the tolerogenic potential of paricalcitol (Pari), a vitamin D analog, when administered by an epicutaneous route in association with MOG35–55. This combination successfully controlled EAE severity when applied three and 11 days after EAE induction [ 51 ]. We recently observed that an early intervention with VitD, delivered 24 hours after experimental encephalomyelitis induction, prevented neurodegeneration by downmodulating both inflammasome and oxidative stress [ 32 ].…”