Francesca Ruffini

Intrathecal Delivery of IFN-γ Protects C57BL/6 Mice from Chronic-Progressive Experimental Autoimmune Encephalomyelitis by Increasing Apoptosis of Central Nervous System-Infiltrating Lymphocytes

The exclusive detrimental role of proinflammatory cytokines in demyelinating diseases of the CNS, such as multiple sclerosis, is controversial. Here we show that the intrathecal delivery of an HSV-1-derived vector engineered with the mouse IFN-γ gene leads to persistent (up to 4 wk) CNS production of IFN-γ and inhibits the course of a chronic-progressive form of experimental autoimmune encephalomyelitis (EAE) induced in C57BL/6 mice by myelin oligodendrocyte glycoprotein (MOG)35–55. Mice treated with the IFN-γ-containing vector before EAE onset showed an earlier onset but a milder course of the disease compared with control mice treated with the empty vector. In addition, 83% of IFN-γ-treated mice completely recovered within 25 days post immunization, whereas control mice did not recover up to 60 days post immunization. Mice treated with the IFN-γ-containing vector within 1 wk after EAE onset partially recovered from the disease within 25 days after vector injection, whereas control mice worsened. Recovery from EAE in mice treated with IFN-γ was associated with a significant increase of CNS-infiltrating lymphocytes undergoing apoptosis. During the recovery phase, the mRNA level of TNFR1 was also significantly increased in CNS-infiltrating cells from IFN-γ-treated mice compared with controls. Our results further challenge the exclusive detrimental role of IFN-γ in the CNS during EAE/multiple sclerosis, and indicate that CNS-confined inflammation may induce protective immunological countermechanisms leading to a faster clearance of encephalitogenic T cells by apoptosis, thus restoring the immune privilege of the CNS.

Myeloid microvesicles are a marker and therapeutic target for neuroinflammation.

Microvesicles (MVs) have been indicated as important mediators of intercellular communication and are emerging as new biomarkers of tissue damage. Our previous data indicate that reactive microglia/macrophages release MVs in vitro. The aim of the study was to evaluate whether MVs are released by microglia/macrophages in vivo and whether their number varies in brain inflammatory conditions, such as multiple sclerosis (MS).

Fibroblast growth factor-II gene therapy reverts the clinical course and the pathological signs of chronic experimental autoimmune encephalomyelitis in C57BL/6 mice.

The development of therapies aimed to promote remyelination is a major issue in chronic inflammatory demyelinating disorders of the central nervous system (CNS) such as multiple sclerosis (MS), where the permanent neurological impairment is due to the axonal loss resulting from recurrent episodes of immune-mediated demyelination. Here, we show that the intrathecal injection of a herpes simplex virus (HSV) type-1 replication-defective multigene vector, engineered with the human fibroblast growth factor (FGF)-II gene (TH:bFGF vector), was able to significantly revert in C57BL/6 mice the clinicopathological signs of chronic experimental autoimmune encephalomyelitis (EAE), the animal model of MS. The treatment with the TH:bFGF vector was initiated within 1 week after the clinical onset of EAE and was effective throughout the whole follow-up period (ie 60 days). The disease-ameliorating effect in FGF-II-treated mice was associated with: (1) CNS production of FGF-II from vector-infected cells which were exclusively located around the CSF space (ependymal, choroidal and leptomeningeal cells); (2) significant decrease (P < 0.01) of the number of myelinotoxic cells (T cells and macrophages) both in the CNS parenchyma and in the leptomeningeal space; and (3) significant increase (P < 0.01) of the number of oligodendrocyte precursors and of myelin-forming oligodendrocytes in areas of demyelination and axonal loss. Our results indicate that CNS gene therapy using HSV-1-derived vector coding for neurotrophic factors (ie FGF-II) is a safe and non-toxic approach that might represent a potential useful ‘alternative’ tool for the future treatment of immune-mediated demyelinating diseases.

Central nervous system gene therapy with interleukin-4 inhibits progression of ongoing relapsing-remitting autoimmune encephalomyelitis in Biozzi AB/H mice.

Multiple sclerosis (MS) is an immune-mediated inflammatory disease of the central nervous system (CNS) that might benefit from anti-inflammatory therapies. However, systemic delivery of anti-inflammatory drugs in MS patients has so far been disappointing, mostly due to the limited capacity of these molecules to enter the CNS. We injected into the cisterna magna (i.c.) of Biozzi AB/H mice affected by a relapsing–remitting form of experimental autoimmune encephalomyelitis (EAE), the animal model of MS, a non-replicative herpes simplex virus (HSV) type-1-derived vector containing the interleukin (IL)-4 gene (d120:LacZ:IL-4). CNS delivery of the d120:LacZ:IL-4 vector, after EAE onset, induced the in situ production of IL-4 by CNS-resident cells facing the cerebrospinal fluid (CSF) spaces and reduced by 47% (P < 0.02) the disease-related deaths. compared with mice treated with the control d120:lacz vector, il-4-treated mice also showed a shorter duration of the first eae attack, a longer inter-relapse period, and a reduction in the severity and duration of the first relapse. protection from eae progression in il-4-treated mice was associated with activation of microglia in spinal cord areas where mrna content of the pro-inflammatory chemokines, macrophage chemoattractant protein-1 (mcp-1) and rantes, was reduced and that of the anti-inflammatory cytokine il-4 was increased. finally, cns-infiltrating mononuclear cells from il-4-treated mice produced lower levels of mcp-1 mrna compared with control mice. our results, showing that il-4 gene delivery using hsv-1 vectors induces protection from eae by in situ modulating the cytokine/chemokine-mediated circuits sustaining effector cell functions, indicate that the intrathecal ‘therapeutic’ use of nonreplicative hsv-1-derived vectors containing anti-inflammatory molecules might represent an alternative strategy in inflammatory diseases of the cns.

Rapamycin inhibits relapsing experimental autoimmune encephalomyelitis by both effector and regulatory T cells modulation

Rapamycin is an oral immunosuppressant drug previously reported to efficiently induce naturally occurring CD4(+)CD25(+)FoxP3(+) regulatory T ((n)T(reg)) cells re-establishing long-term immune self-tolerance in autoimmune diseases. We investigated the effect of rapamycin administration to SJL/j mice affected by PLP(139-151)-induced relapsing-remitting experimental autoimmune encephalomyelitis (RR-EAE). We found that oral or intraperitoneal treatment at the peak of disease or at the end of the first clinical attack, dramatically ameliorated the clinical course of RR-EAE. Treatment suspension resulted in early reappearance of disease. Clinical response was associated with reduced central nervous system demyelination and axonal loss. Rapamycin induced suppression of IFN-gamma, and IL-17 release from antigen-specific T cells in peripheral lymphoid organs. While CD4(+)FoxP3(+) cells were unaffected, we observed disappearance of CD4(+)CD45RB(high) effector T (T(eff)) cells and selective expansion of T(reg) cells bearing the CD4(+)CD45RB(low)FoxP3(+)CD25(+)CD103(+) extended phenotype. Finally, the dual action of rapamycin on both T(eff) and T(reg) cells resulted in modulation of their ratio that closely paralleled disease course. Our data show that rapamycin inhibits RR-EAE, provide evidence for the immunological mechanisms, and indicate this compound as a potential candidate for the treatment of multiple sclerosis.

iPSC-derived neural precursors exert a neuroprotective role in immune-mediated demyelination via the secretion of LIF

The possibility of generating neural stem/precursor cells (NPCs) from induced pluripotent stem cells (iPSCs) has opened a new avenue of research that might nurture bench-to-bedside translation of cell transplantation protocols in central nervous system myelin disorders. Here we show that mouse iPSC-derived NPCs (miPSC-NPCs)-when intrathecally transplanted after disease onset-ameliorate clinical and pathological features of experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. Transplanted miPSC-NPCs exert the neuroprotective effect not through cell replacement, but through the secretion of leukaemia inhibitory factor that promotes survival, differentiation and the remyelination capacity of both endogenous oligodendrocyte precursors and mature oligodendrocytes. The early preservation of tissue integrity limits blood-brain barrier damage and central nervous system infiltration of blood-borne encephalitogenic leukocytes, ultimately responsible for demyelination and axonal damage. While proposing a novel mechanism of action, our results further expand the therapeutic potential of NPCs derived from iPSCs in myelin disorders.

Delivery to the central nervous system of a nonreplicative herpes simplex type 1 vector engineered with the interleukin 4 gene protects rhesus monkeys from hyperacute autoimmune encephalomyelitis

Systemic administration of antiinflammatory molecules to patients affected by immune-mediated inflammatory demyelinating diseases of the central nervous system (CNS) has limited therapeutic efficacy due to the presence of the blood-brain barrier (BBB). We found that three of five rhesus monkeys injected intrathecally with a replication-defective herpes simplex virus (HSV) type 1-derived vector engineered with the human interleukin 4 (IL-4) gene were protected from an hyperacute and lethal form of experimental autoimmune encephalomyelitis induced by whole myelin. The intrathecally injected vector consistently diffused within the CNS via the cerebrospinal fluid and infected ependymal cells, which in turn sustained in situ production of IL-4 without overt immunological or toxic side effects. In EAE-protected monkeys, IL-4-gene therapy significantly decreased the number of brain as well as spinal cord inflammatory perivenular infiltrates and the extent of demyelination, necrosis, and axonal loss. The protective effect was associated with in situ downregulation of inflammatory mediators such as tumor necrosis factor alpha (TNF-alpha) and monocyte chemoattractant protein 1 (MCP-1), upregulation of transforming growth factor beta (TGF-beta), and preservation of BBB integrity. Our results indicate that intrathecal delivery of HSV-1-derived vectors containing antiinflammatory cytokine genes may play a major role in the future therapeutic armamentarium of inflammatory CNS-confined demyelinating diseases and, in particular, in the most fulminant forms where conventional therapeutic approaches have, so far, failed to achieve a satisfactory control of the disease evolution.

IL-17– and IFN-γ–Secreting Foxp3 + T Cells Infiltrate the Target Tissue in Experimental Autoimmunity

CD4+Foxp3+ regulatory T cells (Tregs) have been considered crucial in controlling immune system homeostasis, and their derangement is often associated to autoimmunity. Tregs identification is, however, difficult because most markers, including CD25 and Foxp3, are shared by recently activated T cells. We show in this paper that CD4+Foxp3+ T cells are generated in peripheral lymphoid organs on immunization and readily accumulate in the target organ of an autoimmune reaction, together with classical inflammatory cells, constituting up to 50% of infiltrating CD4+ T cells. Most CD4+Foxp3+ T cells are, however, CD25− and express proinflammatory cytokines such as IL-17 and IFN-γ, questioning their suppressive nature. Moreover, in vitro CD4+ T lymphocytes from naive and autoimmune mice, stimulated to differentiate into Th1, Th2, Th17, and induced Tregs, display early mixed expression of lineage-specific markers. These results clearly point to an unprecedented plasticity of naive CD4+ T cells, that integrating inflammatory signals may change their fate from the initial lineage commitment to a different functional phenotype.

Laquinimod prevents inflammation-induced synaptic alterations occurring in experimental autoimmune encephalomyelitis

Background There are two generally accepted strategies for treating multiple sclerosis (MS), preventing central nervous system (CNS) damage indirectly through immunomodulatory interventions and/or repairing CNS damage by promoting remyelination. Both approaches also provide neuroprotection since they can prevent, indirectly or directly, axonal damage. Objective Recent experimental and clinical evidence indicates that the novel immunomodulatory drug laquinimod can exert a neuroprotective role in MS. Whether laquinimod-mediated neuroprotection is exerted directly on neuronal cells or indirectly via peripheral immunomodulation is still unclear. Methods C57Bl/6 experimental autoimmune encephalomyelitis (EAE) mice, immunised with myelin oligodendrocyte glycoprotein (MOG)35-55 peptide, were treated for 26 days with subcutaneous daily injections of laquinimod (from 1 to 25 mg/kg). Patch clamp electrophysiology was performed on acute brain striatal slices from EAE mice treated with daily (25 mg/kg) laquinimod and on acute brain striatal slices from control mice bathed with laquinimod (1–30 µM). Results Both preventive and therapeutic laquinimod treatment fully prevented the alterations of GABAergic synapses induced by EAE, the first limiting also glutamatergic synaptic alterations. This dual effect might, in turn, have limited glutamatergic excitotoxicity, a phenomenon previously observed early during EAE and possibly correlated with later axonal damage. Furthermore, laquinimod treatment also preserved cannabinoid CB1 receptor sensitivity, normally lost during EAE. Finally, laquinimod per se was able to regulate synaptic transmission by increasing inhibitory post-synaptic currents and, at the same time, reducing excitatory post-synaptic currents. Conclusions Our data suggest a novel neuroprotective mechanism by which laquinimod might in vivo protect from neuronal damage occurring as a consequence of inflammatory immune-mediated demyelination.

Immunological markers in multiple sclerosis.

Abstract Multiple sclerosis (MS) is characterized by the presence in the central nervous system (CNS) of perivascular inflammatory infiltrates containing, among others, autoreactive T cells and activated macrophages. These observations indicate that MS is a T cell-mediated CNS-confined chronic inflammatory demyelinating disease in which the ultimate effector cell is the activated macrophage. The inflammatory process, leading to patchy demyelination and axonal loss, is mainly sustained by pro-inflammatory cytokines that, along with chemokines, adhesion molecules and metalloproteases, modulate at different levels the pathogenic process underlying MS. Due to their central role in MS pathogenesis, “inflammatory” molecules might represent suitable peripheral markers of disease (disease-trail) and/or disease activity (state-trait). However, reliable disease-trait or state-trait immunological markers for MS have not yet been identified. The intrinsic characteristics of these molecules (i. e. autocrine/paracrine activity, short half-life, redundancy) may in part explain their inconsistency as disease markers. Additionally, the unreliability of methodologies and the lack of careful patient stratification can also, at least in part, account for the unsatisfactory results so far obtained.