Gianluca Svegliati Baroni

Bio: Gianluca Svegliati Baroni is an academic researcher from Marche Polytechnic University. The author has contributed to research in topics: Hepatic stellate cell & Sorafenib. The author has an hindex of 31, co-authored 62 publications receiving 3650 citations. Previous affiliations of Gianluca Svegliati Baroni include Instituto Politécnico Nacional & University of Trieste.

Hedgehog signaling regulates epithelial-mesenchymal transition during biliary fibrosis in rodents and humans

Abstract: Epithelial-mesenchymal transitions (EMTs) play an important role in tissue construction during embryogenesis, and evidence suggests that this process may also help to remodel some adult tissues after injury. Activation of the hedgehog (Hh) signaling pathway regulates EMT during development. This pathway is also induced by chronic biliary injury, a condition in which EMT has been suggested to have a role. We evaluated the hypothesis that Hh signaling promotes EMT in adult bile ductular cells (cholangiocytes). In liver sections from patients with chronic biliary injury and in primary cholangiocytes isolated from rats that had undergone bile duct ligation (BDL), an experimental model of biliary fibrosis, EMT was localized to cholangiocytes with Hh pathway activity. Relief of ductal obstruction in BDL rats reduced Hh pathway activity, EMT, and biliary fibrosis. In mouse cholangiocytes, coculture with myofibroblastic hepatic stellate cells, a source of soluble Hh ligands, promoted EMT and cell migration. Addition of Hh-neutralizing antibodies to cocultures blocked these effects. Finally, we found that EMT responses to BDL were enhanced in patched-deficient mice, which display excessive activation of the Hh pathway. Together, these data suggest that activation of Hh signaling promotes EMT and contributes to the evolution of biliary fibrosis during chronic cholestasis.

Interferon gamma decreases hepatic stellate cell activation and extracellular matrix deposition in rat liver fibrosis

Abstract: Interferon gamma (IFN-γ) inhibits in vitro the activation of hepatic stellate cells (HSC), the primary extracellular matrix-producing cells in liver fibrosis. This study was undertaken to determine in vivo the effect of IFN-γ in the rat model of liver fibrosis induced by dimethylnitrosamine (DMN), where HSC activation represents an early response to cell injury. Rats were killed after 1 or 3 weeks of treatment with DMN, IFN-γ, DMN + IFN-γ, or saline. Immunohistochemistry was used to identify proliferating (desmin-positive/bromodeoxyuridine (BrdU)-positive cells) and activated (α-smooth-muscle actin [α-SMA]-positive cells) HSCs. Collagen deposition was determined colorimetrically and by morphometry. The parenchymal extension of desmin- and actin-positive cells and of fibrotic tissue was measured by point-counting technique and expressed as a percentage of area. Western blot was used to determine laminin and fibronectin accumulation. The levels of messenger RNA (mRNA) for procollagen type I, fibronectin, and laminin were evaluated by Northern blot. No differences were observed in rats treated with either saline or IFN-γ alone. IFN-γ reduced HSC activation induced by liver injury, as shown by the decreased number of proliferating HSC and the reduction of parenchymal area occupied by α-SMA-positive cells observed in DMN + IFN-γ-treated animals compared with the DMN group. This was associated with reduced collagen, laminin, and fibronectin accumulation and lower levels of mRNA for procollagen type I, fibronectin, and laminin in the DMN + IFN-γ group. Thus, this study indicates that IFN-γ reduces extracellular matrix deposition in vivo by inhibition of HSC activation.

Mechanisms of fibrosis: therapeutic translation for fibrotic disease

Abstract: Fibrosis is a key aspect of many chronic inflammatory diseases and can affect almost every tissue in the body. This review discusses recent advances in our understanding of the mechanisms of fibrosis, focusing on the innate and adaptive immune responses. It also describes how some of these crucial pathogenic pathways are being therapeutically targeted in the clinic.

Hepatic Stellate Cells: Protean, Multifunctional, and Enigmatic Cells of the Liver

Abstract: The hepatic stellate cell has surprised and engaged physiologists, pathologists, and hepatologists for over 130 years, yet clear evidence of its role in hepatic injury and fibrosis only emerged following the refinement of methods for its isolation and characterization. The paradigm in liver injury of activation of quiescent vitamin A-rich stellate cells into proliferative, contractile, and fibrogenic myofibroblasts has launched an era of astonishing progress in understanding the mechanistic basis of hepatic fibrosis progression and regression. But this simple paradigm has now yielded to a remarkably broad appreciation of the cell's functions not only in liver injury, but also in hepatic development, regeneration, xenobiotic responses, intermediary metabolism, and immunoregulation. Among the most exciting prospects is that stellate cells are essential for hepatic progenitor cell amplification and differentiation. Equally intriguing is the remarkable plasticity of stellate cells, not only in their variable intermediate filament phenotype, but also in their functions. Stellate cells can be viewed as the nexus in a complex sinusoidal milieu that requires tightly regulated autocrine and paracrine cross-talk, rapid responses to evolving extracellular matrix content, and exquisite responsiveness to the metabolic needs imposed by liver growth and repair. Moreover, roles vital to systemic homeostasis include their storage and mobilization of retinoids, their emerging capacity for antigen presentation and induction of tolerance, as well as their emerging relationship to bone marrow-derived cells. As interest in this cell type intensifies, more surprises and mysteries are sure to unfold that will ultimately benefit our understanding of liver physiology and the diagnosis and treatment of liver disease.