The channel-activating protease CAP1/Prss8 is required for placental labyrinth maturation

The serine protease CAP1/Prss8 is crucial for skin barrier function, lung alveolar fluid clearance and has been unveiled as diagnostic marker for specific cancer types. Here, we show that a constitutive knockout of CAP1/Prss8 leads to embryonic lethality. These embryos presented no specific defects, but it is during this period, and in particular at E13.5, that wildtype placentas show an increased expression of CAP1/Prss8, thus suggesting a placental defect in the knockout situation. The placentas of knockout embryos exhibited significantly reduced vascular development and incomplete cellular maturation. In contrary, epiblast-specific deletion of CAP1/Prss8 allowed development until birth. These CAP1/Prss8-deficient newborns presented abnormal epidermis, and died soon after birth due to impaired skin function. We thus conclude that a late placental insufficiency might be the primary cause of embryonic lethality in CAP1/Prss8 knockouts. This study highlights a novel and crucial role for CAP1/Prss8 in placental development and function.

Nano-stenciled RGD-gold patterns that inhibit focal contact maturation induce lamellipodia formation in fibroblasts

Cultured fibroblasts adhere to extracellular substrates by means of cell-matrix adhesions that are assembled in a hierarchical way, thereby gaining in protein complexity and size. Here we asked how restricting the size of cell-matrix adhesions affects cell morphology and behavior. Using a nanostencil technique, culture substrates were patterned with gold squares of a width and spacing between 250 nm and 2 µm. The gold was functionalized with RGD peptide as ligand for cellular integrins, and mouse embryo fibroblasts were plated. Limiting the length of cell-matrix adhesions to 500 nm or less disturbed the maturation of vinculin-positive focal complexes into focal contacts and fibrillar adhesions, as indicated by poor recruitment of ?5-integrin. We found that on sub-micrometer patterns, fibroblasts spread extensively, but did not polarize. Instead, they formed excessive numbers of lamellipodia and a fine actin meshwork without stress fibers. Moreover, these cells showed aberrant fibronectin fibrillogenesis, and their speed of directed migration was reduced significantly compared to fibroblasts on 2 µm square patterns. Interference with RhoA/ROCK signaling eliminated the pattern-dependent differences in cell morphology. Our results indicate that manipulating the maturation of cell-matrix adhesions by nanopatterned surfaces allows to influence morphology, actin dynamics, migration and ECM assembly of adhering fibroblasts.

Cellular immune response, stress resistance and competitiveness in nestling great tits in relation to maternally transmitted carotenoids

1. Egg yolks contain carotenoids that protect biological molecules against free-radical damage and promote maturation of the immune system. Availability of carotenoids to birds is often limited. Trade-offs can thus arise in the allocation of carotenoids to different physiological functions, and mothers may influence the immunocompetence of nestlings by modulating the transfer of carotenoid to the yolk.;2. In the great tit Parus major, we experimentally manipulated the dietary supply of carotenoid to mothers, and partially cross-fostered hatchlings to investigate the effect of an increased availability of carotenoids during egg laying on immunocompetence of nestlings.;3. In addition, we infested half of the nests with hen fleas Ceratophyllus gallinae to investigate the relationship between carotenoid availability, resistance to ectoparasites and immunocompetence.;4. We found that the procedure of cross-fostering can reduce the immune response of nestlings, but this effect can be compensated by the maternally transferred carotenoids. Cross-fostered nestlings of carotenoid-supplemented females show a similar immune response to non-cross-fostered nestlings, while cross-fostered nestlings of control females mounted a weaker cell-mediated immune response. This suggests that yolk carotenoids may help nestlings to cope with stress, for example the one generated by cross-fostering and/or they may enhance nestling competitiveness.;5. There was no statistically significant interaction between parasite and carotenoid treatments, as would be expected if carotenoids helped nestlings to fight parasites. Under parasite pressure, however, lighter nestlings raised a lower immune response, while the immune response was only weakly correlated with body mass in uninfested nests.

Tenomodulin is necessary for tenocyte proliferation and tendon maturation

Tenomodulin (Tnmd) is a member of a new family of type II transmembrane glycoproteins. It is predominantly expressed in tendons, ligaments, and eyes, whereas the only other family member, chondromodulin I (ChM-I), is highly expressed in cartilage and at lower levels in the eye and thymus. The C-terminal extracellular domains of both proteins were shown to modulate endothelial-cell proliferation and tube formation in vitro and in vivo. We analyzed Tnmd function in vivo and provide evidence that Tnmd is processed in vivo and that the proteolytically cleaved C-terminal domain can be found in tendon extracts. Loss of Tnmd expression in gene targeted mice abated tenocyte proliferation and led to a reduced tenocyte density. The deposited amounts of extracellular matrix proteins, including collagen types I, II, III, and VI and decorin, lumican, aggrecan, and matrilin-2, were not affected, but the calibers of collagen fibrils varied significantly and exhibited increased maximal diameters. Tnmd-deficient mice did not have changes in tendon vessel density, and mice lacking both Tnmd and ChM-I had normal retinal vascularization and neovascularization after oxygen-induced retinopathy. These results suggest that Tnmd is a regulator of tenocyte proliferation and is involved in collagen fibril maturation but do not confirm an in vivo involvement of Tnmd in angiogenesis.