Thymosin alpha1 activates the TLR9/MyD88/IRF7-dependent murine cytomegalovirus sensing for induction of anti-viral responses in vivo.

Reactivation of latent human cytomegalovirus following allogeneic transplantation is a major cause of morbidity and mortality and predisposes to severe complications. Thymosin alpha1 (Talpha1), a naturally occurring thymic peptide, is approved for treatment of some viral infections and as an immune adjuvant. Talpha1 successfully primed dendritic cells (DCs) for anti-microbial T helper type 1 resistance through Toll-like receptor (TLR) 9 signaling. We sought to determine here whether Talpha1 could play a role in murine cytomegalovirus infection (MCMV). To this purpose, susceptible, resistant and TLR-deficient mice were infected with MCMV, treated with Talpha1 and assessed for protection in term of microbiological and immunological parameters. Talpha1 protected susceptible and resistant mice from MCMV infection. The anti-viral effect of Talpha1 occurred through the activation of plasmacytoid DCs via the TLR9/myeloid differentiation primary response gene 88-dependent viral recognition sensing, leading to the activation of IFN regulatory factor 7 and the promotion of the IFN-alpha/IFN-gamma-dependent effector pathway.

Efficient production by sperm-mediated gene transfer of human decay accelerating factor (hDAF) transgenic pigs for xenotransplantation.

A large number of hDAF transgenic pigs to be used for xenotransplantation research were generated by using sperm-mediated gene transfer (SMGT). The efficiency of transgenesis obtained with SMGT was much greater than with any other method. In the experiments reported, up to 80% of pigs had the transgene integrated into the genome. Most of the pigs carrying the hDAF gene transcribed it in a stable manner (64%). The great majority of pigs that transcribed the gene expressed the protein (83%). The hDAF gene was transmitted to progeny. Expression was stable and found in caveolae as it is in human cells. The expressed gene was functional based on in vitro experiments performed on peripheral blood mononuclear cells. These results show that our SMGT approach to transgenesis provides an efficient procedure for studies involving large animal models.

Peripheral nerve extracellular matrix remodeling in Charcot-Marie-Tooth type I disease.

Charcot-Marie-Tooth type 1 disease (CMT1) is a group of inherited demyelinating neuropathies caused by mutations in genes expressed by myelinating Schwann cells. Rather than demyelination per se, alterations of Schwann cell-axon interactions have been suggested as the main cause of motor-sensory impairment in CMT1 patients. In an attempt to identify molecules that may be involved in such altered interactions, the extracellular matrix (ECM) remodeling occurring in CMT1 sural nerves was studied. For comparison, both normal sural nerves and sural nerves affected by neuropathies of different origin were used. The study was performed by immunohistochemical analysis using antibodies against collagen types I, III, IV, V, and VI and the glycoproteins fibronectin, laminin, vitronectin and tenascin. Up-regulation of collagens, fibronectin and laminin was commonly found in nerve biopsy specimens from patients affected by CMT1 and control diseases, but higher levels of overexpression were usually observed in CMT1 cases. On the other hand, vitronectin and tenascin appeared preferentially induced in CMT1 compared to other pathologies investigated here. Vitronectin, whose expression in normal nerves was limited to perineurial layers and to the walls of epineurial and endoneurial vessels, became strongly and diffusely expressed in the endoneurium in most CMT1 biopsy specimens. The expression of tenascin, confined to the perineurium, to vessel walls and to the nodes of Ranvier in normal nerves, was displaced and extended along the internodes of several nerve fibers in the majority of CMT1 nerves. Thus, compared with our pathological controls CMT1 seemed to determine the most extensive remodeling of peripheral nerve ECM.

Retinoic acid inhibits fibronectin and laminin synthesis and cell migration of human pleural mesothelioma in vitro.

The effects of retinoic acid (RA) on cell replication, fibronectin and laminin synthesis, integrin expression and haptotactic migration of three mesothelioma cell cultures of different histotype, one epithelioid, one fibromatous and one biphasic, were evaluated. Cell growth was not affected by RA, while RA treatment decreased the synthesis of fibronectin and laminin and inhibited the migration of all three mesotheliomas on substrates of fibronectin and laminin; on the contrary, the expression of some integrins was not significantly modified by RA. These data indicate that RA may lead to a decrease of mesothelioma cell local invasion; this can correlate with a modification induced by RA on mesothelioma tumor progression in vivo.