T helper (Th) 17 cells have recently been implicated in psoriasis pathogenesis, but mechanisms of how these cells traffic into inflamed skin are unknown. By immunostaining for interleukin (IL)-17A and IL-22, we show numerous cells present in psoriasis lesions that produce these cytokines. We next found that Th17 cytokines (IL-17A, IL-22, and tumor necrosis factor (TNF)-α) markedly increased the expression of CC chemokine ligand (CCL) 20, a CC chemokine receptor (CCR)6 ligand, in human keratinocyte monolayer and raft cultures in a dose- and time-dependent manner. Lastly, we showed in mice that subcutaneous injection with recombinant IL-17A, IL-22, or TNF-α led to the upregulation of both CCL20 and CCR6 expression in skin as well as cutaneous T-cell infiltration. Taken together, these data show that Th17 cytokines stimulate CCL20 production in vitro and in vivo, and thus provide a potential explanation of how CCR6-positive Th17 cells maintain their continual presence in psoriasis through a positive chemotactic feedback loop.

Mutations of fibroblast growth factor receptor 3 (FGFR3) are responsible for achondroplasia (ACH) and related dwarfing conditions in humans. The pathogenesis involves constitutive activation of FGFR3, which inhibits proliferation and differentiation of growth plate chondrocytes. Here we report that activating mutations in FGFR3 increase the stability of the receptor. Our results suggest that the mutations disrupt c-Cbl-mediated ubiquitination that serves as a targeting signal for lysosomal degradation and termination of receptor signaling. The defect allows diversion of actively signaling receptors from lysosomes to a recycling pathway where their survival is prolonged, and, as a result, their signaling capacity is increased. The lysosomal targeting defect is additive to other mechanisms proposed to explain the pathogenesis of ACH.

Background and Aims Due to the shortage of donor organs many patients needing liver transplantation cannot receive one. For some liver diseases hepatocyte transplantation could be a viable alternative, but donor cells are currently procured from the same sources as whole organs and thus the supply is severely limited. Methods Here, we investigated the possibility of isolating viable hepatocytes for liver cell therapy from the plentiful source of morgue cadavers. In order to determine the utility of this approach, cells were isolated from the livers of non-heart-beating cadaveric mice long after death and transplanted into fumarylacetoacetate hydrolase (Fah) deficient mice, a model for the human metabolic liver disease hereditary tyrosinemia type I and a stringent in vivo model for hepatic cell transplantation. Results Surprisingly, complete and therapeutic liver repopulation could be achieved with hepatocytes derived up to 27 hours post-mortem. Conclusions Competitive repopulation experiments demonstrated that cadaveric liver cells had a repopulation capacity similar to freshly isolated hepatocytes. Importantly, viable hepatocytes could also be efficiently isolated from cadaveric primate liver (monkey and human). These data provide evidence that non-heart-beating donors could be a suitable source of hepatocytes for much longer time periods than previously thought possible.