Browsing by Author "Acuna, Eric"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Interferon-gamma ameliorates experimental autoimmune encephalomyelitis by inducing homeostatic adaptation of microglia
    (2023) Tichauer, Juan E.; Arellano, Gabriel; Acuna, Eric; Gonzalez, Luis F.; Kannaiyan, Nirmal R.; Murgas, Paola; Panadero-Medianero, Concepcion; Ibanez-Vega, Jorge; Burgos, Paula I.; Loda, Eileah; Miller, Stephen D.; Rossner, Moritz J.; Gebicke-Haerter, Peter J.; Naves, Rodrigo
    Compelling evidence has shown that interferon (IFN)-gamma has dual effects in multiple sclerosis and in its animal model of experimental autoimmune encephalomyelitis (EAE), with results supporting both a pathogenic and beneficial function. However, the mechanisms whereby IFN-gamma may promote neuroprotection in EAE and its effects on central nervous system (CNS)-resident cells have remained an enigma for more than 30 years. In this study, the impact of IFN-gamma at the peak of EAE, its effects on CNS infiltrating myeloid cells (MC) and microglia (MG), and the underlying cellular and molecular mechanisms were investigated. IFN-gamma administration resulted in disease amelioration and attenuation of neuroinflammation associated with significantly lower frequencies of CNS CD11b(+) myeloid cells and less infiltration of inflammatory cells and demyelination. A significant reduction in activated MG and enhanced resting MG was determined by flow cytometry and immunohistrochemistry. Primary MC/MG cultures obtained from the spinal cord of IFN-gamma-treated EAE mice that were ex vivo re-stimulated with a low dose (1 ng/ml) of IFN-gamma and neuroantigen, promoted a significantly higher induction of CD4(+) regulatory T (Treg) cells associated with increased transforming growth factor (TGF)-beta secretion. Additionally, IFN-gamma-treated primary MC/MG cultures produced significantly lower nitrite in response to LPS challenge than control MC/MG. IFN-gamma-treated EAE mice had a significantly higher frequency of CX3CR1(high) MC/MG and expressed lower levels of program death ligand 1 (PD-L1) than PBS-treated mice. Most CX3CR1(high)PD-L1(low)CD11b(+)Ly6G(-) cells expressed MG markers (Tmem119, Sall2, and P2ry12), indicating that they represented an enriched MG subset (CX3CR1(high)PD-L1(low) MG). Amelioration of clinical symptoms and induction of CX3CR1(high)PD-L1(low) MG by IFN-gamma were dependent on STAT-1. RNA-seq analyses revealed that in vivo treatment with IFN-gamma promoted the induction of homeostatic CX3CR1(high)PD-L1(low) MG, upregulating the expression of genes associated with tolerogenic and anti-inflammatory roles and down-regulating pro-inflammatory genes. These analyses highlight the master role that IFN-gamma plays in regulating microglial activity and provide new insights into the cellular and molecular mechanisms involved in the therapeutic activity of IFN-gamma in EAE.
  • No Thumbnail Available
    Item
    Intranasal delivery of interferon-β-loaded nanoparticles induces control of neuroinflammation in a preclinical model of multiple sclerosis: A promising simple, effective, non-invasive, and low-cost therapy
    (2021) Gonzalez, Luis F.; Acuna, Eric; Arellano, Gabriel; Morales, Paola; Sotomayor, Paula; Oyarzun-Ampuero, Felipe; Naves, Rodrigo
    Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS). Interferon (IFN)-beta constitutes one of the first-line therapies to treat MS, but has limited efficacy due to the injectable systemic administration, short half-life, and limited CNS access. To address these limitations, we developed IFN-beta-loaded chitosan/sulfobutylether-beta-cyclodextrin nanoparticles (IFN-beta-NPs) for delivery of IFN-beta into the CNS via the intranasal (i.n.) route. The nanoparticles (NPs) (approximate to 200 nm, polydispersity approximate to 0.1, and zeta potential approximate to 20 mV) were prepared by mixing two aqueous solutions and associated human or murine IFN-beta with high efficiency (90%). Functional in vitro assays showed that IFN-beta-NPs were safe and that IFN-beta was steadily released while retaining biological activity. Biodistribution analysis showed an early and high fluorescence in the brain after nasal administration of fluorescent probe-loaded NPs. Remarkably, mice developing experimental autoimmune encephalomyelitis (EAE), an experimental model of MS, exhibited a significant improvement of clinical symptoms in response to intranasal IFN-beta-NPs (inIFN-beta-NPs), whereas a similar dose of intranasal or systemic free IFN-beta had no effect. Importantly, inIFN-beta-NPs treatment was equally effective despite a reduction of 78% in the total amount of weekly administered IFN-beta. Spinal cords obtained from inIFN-beta-NPs-treated EAE mice showed fewer inflammatory foci and demyelination, lower expression of antigen-presenting and costimulatory proteins on CD11b(+) cells, and lower astrocyte and microglia activation than control mice. Therefore, IFN-beta treatment at tested doses was effective in promoting clinical recovery and control of neuroinflammation in EAE only when associated with NPs. Overall, inIFN beta-NPs represent a potential, effective, non-invasive, and low-cost therapy for MS.