The thyroid TRK-T3 oncogene results from the fusion of the tyrosine kinase (TK) domain of NTRK1 (one of the receptors for the Nerve Growth Factor) on chromosome 1 to sequences of a novel gene, TFG, on chromosome 3. The 68 kDa TRK-T3 fusion oncoprotein displays a constitutive tyrosine kinase activity resulting in its capability to transform mouse NIH3T3 cells. The TFG portion of TRK-T3 contains a coiled-coil domain most likely responsible for the constitutive, ligand-independent activation of the receptor tyrosine kinase activity. We have previously shown that TRK-T3 oncoprotein forms, in vivo, complexes of three or four molecules. By mean of di erent experimental approaches, we show here that TRK-T3 activity depends on oligomers formation. In addition, the analysis of di erent TRK-T3 mutants indicates that the TFG coiled-coil domain and its Nterminal region are both required for the activation and the fully transforming activity of the TRK-T3 oncoprotein, although, most likely, they play a role in di erent steps of the transforming process. The deletion of the coiled-coil domain abrogates the oligomers formation leading to a constitutive activation; the deletion of the Nterminal region, although not a ecting phosphorylation and complexes formation, abrogates transformation, thus suggesting a role in cellular localization and/or interaction with substrata.

As a consequence of a reciprocal translocation t(17;22)(q22;q13) and of supernumerary ring chromosomes derived from the t(17;22), a fusion between the platelet-derived growth factor b-chain (PDGF, c-sis proto-oncogene) and the collagen type 1A1 (COL1A1) genes has been recently described in dermato®brosarco-ma protuberans (DP), an in®ltrating skin tumor (Simon et al., 1997). Although PDGFB has been implicated in transforming processes via autocrine and paracrine pathways, by the activation of the cognate receptor, no direct evidence of its involvement in neoplastic transformation of human tumours has been so far provided. In this report, we have tested the DNA from four DPs in the classical DNA transfection assay onto NIH3T3 ®broblast cell line. All the DNAs induced the formation of transformed foci in the transfected cultures whose derived cell lines were shown to contain a fused sequence comprising the human COL1A1 and PDGF genes. The relative breakpoint regions have been sequenced revealing that this gene fusion deleted exon 1 of PDGF and released the growth factor from its normal regulation. All the biochemical and biological assays were consistent with the model of an autocrine mechanism for NIH3T3 transformation by the human rearranged PDGFB gene involving the activation of the endogeneous PDGF receptor.

Regenerative medicine aims to restore the normal function of diseased or damaged cells, tissues, and organs using a set of different approaches, including cell-based therapies. In the veterinary field, regenerative medicine is strongly related to the use of mesenchymal stromal cells (MSCs), which belong to the body repair system and are defined as multipotent progenitor cells, able to self-replicate and to differentiate into different cell types. This review aims to take stock of what is known about the MSCs and their use in the veterinary medicine focusing on clinical reports on dogs and horses in musculoskeletal diseases, a research field extensively reported in the literature data. Finally, a perspective regarding the use of the secretome and/or extracellular vesicles (EVs) in the veterinary field to replace parental MSCs is provided. The pharmaceuticalization of EVs is wished due to the realization of a Good Manufacturing Practice (GMP product suitable for clinical trials.

Drug-induced hepatotoxicity is a leading cause of clinical trial withdrawal. Therefore, in vitro modeling the hepatic behavior and functionalities is not only crucial to better understand physiological and pathological processes but also to support drug development with reliable high-throughput platforms. Different physiological and pathological models are currently under development and are commonly implemented both within platforms for standard 2D cultures and within tailor-made chambers. This paper introduces Hep3Gel: a hybrid alginate−extracellular matrix (ECM) hydrogel to produce 3D in vitro models of the liver, aiming to reproduce the hepatic chemomechanical niche, with the possibility of adapting its shape to different manufacturing techniques. The ECM, extracted and powdered from porcine livers by a specifically set-up procedure, preserved its crucial biological macromolecules and was embedded within alginate hydrogels prior to crosslinking. The viscoelastic behavior of Hep3Gel was tuned, reproducing the properties of a physiological organ, according to the available knowledge about hepatic biomechanics. By finely tuning the crosslinking kinetics of Hep3Gel, its dualistic nature can be exploited either by self-spreading or adapting its shape to different culture supports or retaining the imposed fiber shape during an extrusion-based 3D-bioprinting process, thus being a shape-shifter hydrogel. The self-spreading ability of Hep3Gel was characterized by combining empirical and numerical procedures, while its use as a bioink was experimentally characterized through rheological a priori printability evaluations and 3D printing tests. The effect of the addition of the ECM was evident after 4 days, doubling the survival rate of cells embedded within control hydrogels. This study represents a proof of concept of the applicability of Hep3Gel as a tool to develop 3D in vitro models of the liver.

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