Gliotoxin induces Mg2+ efflux from intact brain mitochondria

Gliotoxin (GT) is a hydrophobic fungal metabolite of the epipolythiodioxopiperazine group which reacts with membrane thiols. When added to a suspension of energized brain mitochondria, it induces matrix swelling of low amplitude, collapse of membrane potential (DeltaPsi), and efflux of endogenous cations such as Ca2+ and Mg2+, typical events of mitochondrial permeability transition (MPT) induction. These effects are due to opening of the membrane transition pore. The addition of cyclosporin A (CsA) or ADP slightly reduces membrane potential collapse, matrix swelling and Ca2+ efflux; Mg2+ efflux is not affected at all. The presence of exogenous Mg2+ or spermine completely preserve mitochondria against DeltaPsi collapse, matrix swelling and Ca2+ release. Instead, Mg2+ efflux is only slightly affected by spermine. Our results demonstrate that, besides inducing MPT, gliotoxin activates a specific Mg2+ efflux system from brain mitochondria

Development and application of replication-incompetent HSV-1-based vectors

The replication-incompetent HSV-1-based vectors are herpesviruses in which genes that are 'essential' for viral replication have been either mutated or deleted. These deletions have substantially reduced their cytotoxicity by preventing early and late viral gene expression and, together with other deletions involving 'nonessential' genes, have also created space to introduce distinct and independently regulated expression cassettes for different transgenes. Therapeutic effects in gene therapy applications requiring simultaneous and synergic expression of multiple gene products are easily achievable with these vectors. A number of different HSV-1-based nonreplicative vectors for specific gene therapy applications have been developed so far. They have been tested in different gene therapy animal models of neuropathies (Parkinson's disease, chronic pain, spinal cord injury pain) and lysosomal storage disorders. Many replication-incompetent HSV-1-based vectors have also been used either as potential anti-herpes vaccines, as well as vaccine vectors for other pathogens in murine and simian models. Anticancer gene therapy approaches have also been successfully set up; gene therapy to other targets by using these vectors is feasible

Effects of defective herpes simplex vectors expressing neurotrophic factors on the proliferation and differentiation of nervous cells in vivo

Neurotrophic factors (NTFs) are known to govern the processes involved in central nervous system cell proliferation and differentiation. Thus, they represent very attractive candidates for use in the study and therapy of neurological disorders. We constructed recombinant herpesvirus-based-vectors capable of expressing fibroblast growth factor-2 (FGF-2) and ciliary neurotrophic factor (CNTF) alone or in combinations. In vitro, vectors expressing FGF-2 and CNTF together, but not those expressing either NTF alone, caused proliferation of O-2A progenitors. Furthermore, based on double-labeling experiments performed using markers for neurons (MAP-2), oligodendrocytes (CNPase) and astrocytes (GFAP), most of the new cells were identified as astrocytes, but many expressed neuronal or oligodendrocytic markers. In vivo, vectors have been injected in the rat hippocampus. At 1 month after inoculation, a highly significant increase in BrdU-positive cells was observed in the dentate gyrus of animals injected with the vector expressing FGF-2 and CNTF together, but not in those injected with vectors expressing the single NTFs. Furthermore, double-labeling experiments confirmed in vitro data, that is, most of the new cells identified as astrocytes, some as neurons or oligodendrocytes. These data show the feasibility of the vector approach to induce proliferation and differentiation of neurons and/or oligodendrocytes in vivo

Virus erpetici come vettori vaccinali

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Effects of defective herpes simplex vectors expressing neurotrophic factors on the proliferation and differentiation of nervous cells in vivo

Neurotrophic factors (NTFs) are known to govern the processes involved in central nervous system cell proliferation and differentiation. Thus, they represent very attractive candidates for use in the study and therapy of neurological disorders. We constructed recombinant herpesvirus-based-vectors capable of expressing fibroblast growth factor-2 (FGF-2) and ciliary neurotrophic factor (CNTF) alone or in combinations. In vitro, vectors expressing FGF-2 and CNTF together, but not those expressing either NTF alone, caused proliferation of O-2A progenitors. Furthermore, based on double-labeling experiments performed using markers for neurons (MAP-2), oligodendrocytes (CNPase) and astrocytes (GFAP), most of the new cells were identified as astrocytes, but many expressed neuronal or oligodendrocytic markers. In vivo, vectors have been injected in the rat hippocampus. At 1 month after inoculation, a highly significant increase in BrdU-positive cells was observed in the dentate gyrus of animals injected with the vector expressing FGF-2 and CNTF together, but not in those injected with vectors expressing the single NTFs. Furthermore, double-labeling experiments confirmed in vitro data, that is, most of the new cells identified as astrocytes, some as neurons or oligodendrocytes. These data show the feasibility of the vector approach to induce proliferation and differentiation of neurons and/or oligodendrocytes in vivo

Replication-deficient mutant Herpes Simplex Virus-1 targets professional antigen presenting cells and induces efficient CD4+ T helper responses.

Both neutralizing antibodies and cytotoxic T-cells are necessary to control a viral infection. However, vigorous T helper responses are essential for their elicitation and maintenance. Here we show that a recombinant replication-deficient Herpes Simplex Virus (HSV)-1 vector encoding the Human Immunodeficiency Virus (HIV)-1 matrix protein p17 (T0-p17) was capable of infecting professional antigen presenting cells (APCs) in vitro and in vivo. The injection of T0-p17 in the mouse dermis generated a strong p17-specific CD4+ T helper response preceding both p17-specific humoral and effector T cell responses. Moreover, we show that T0-p17 infection did not interfere with the endogenous processing of the transgene encoded antigen, since infected APCs were able to evoke a strong recall response in vitro. Our results demonstrate that replication-deficient HSV vectors can be appealing candidates for the development of vaccines able to trigger T helper responses