The polycystin 1-C-terminal fragment stimulates ERK-dependent spreading of renal epithelial cells

Polycystin 1, the product of the PKD1 gene, is mutated in autosomal dominant polycystic kidney disease, a disease characterized by renal cyst formation and progressive renal failure. We show that expression of the C-terminal domain of human polycystin-1 (PKD1-CT) triggers spreading of isolated inner medullary collecting duct cells, a process mediated by Erk. As inner medullary collecting duct cells spread, PKD1-CT localizes to cell-extracellular matrix contacts, interacts with focal adhesion proteins Fak and paxillin, and stimulates Fak phosphorylation, paxillin phosphorylation, Fak-paxillin association, and formation of small focal complexes. PKD1-CT-mediated spreading requires membrane localization and the integrity of the C-terminal protein binding sites. We additionally show that Pkd1 null proximal tubule cells generated from Pkd1(flox/-):TSLargeT mice by in vitro Cre recombinase transfection demonstrate diminished spreading when compared with Pkd(flox/-) heterozygous parental cells. These findings suggest that membrane-bound PC1 has a central role in regulating morphogenic protein signaling at cell-matrix interfaces in non-confluent cells.     

Molecular insights into evolution of the vertebrate gut: focus on stomach and parietal cells in the marsupial, Macropus eugenii

Gastrulation in vertebrate embryos results in the formation of the primary germ layers: ectoderm, mesoderm and endoderm, which contain the progenitors of the tissues of the entire fetal body. Extensive studies undertaken in Xenopus, zebrafish and mouse have revealed a high degree of conservation in the genes and cellular mechanisms regulating endoderm formation. Nodal, Mix and Sox gene factor families have been implicated in the specification of the endoderm across taxa. Considerably less is known about endoderm development in marsupials. In this study we review what is known about the molecular aspects of endoderm development, focusing on evolution and development of the stomach and parietal cells and highlight recent studies on parietal cells in the stomach of Tammar Wallaby, Macropus eugenii. Although the regulation of parietal cells has been extensively studied, very little is known about the regulation of parietal cell differentiation. Intriguingly, during late-stage forestomach maturation in M. eugenii, there is a sudden and rapid loss of parietal cells, compared with the sharp increase in parietal cell numbers in the hindstomach region. This has provided a unique opportunity to study the development and regulation of parietal cell differentiation. A PCR-based subtractive hybridization strategy was used to identify candidate genes involved in this phenomenon. This will allow us to dissect the molecular mechanisms that underpin regulation of parietal cell development and differentiation, which have been a difficult process to study and provide markers that can be used to study the evolutionary origin of these cells in vertebrates.     

Coevolution of male and female reproductive structures in Drosophila

The morphology of male genitalia whilst stable within species, exhibits huge interspecific variation. This variation is likely to be as a result of sexual selection due to the direct involvement of these reproductive structures in mating and sperm transfer. In contrast, internal soft tissue components of the genitalia are generally poorly investigated as they are not directly involved in physical and mechanical adequacy during sperm transfer. However, these soft tissue structures may also drive differential male–female interactions, particularly in internally fertilising organisms where females have the ability to store sperm and bias male reproductive success. In this paper we use the drosophila model to investigate the role of male and female reproductive elements in sexual selection. Our meta-analysis supplemented with additional new data clearly shows that within species, sperm length versus testis length, and sperm length versus seminal receptacle length, are highly correlated. Thus, independent of the phylogenetic relationship among species, gamete evolution is likely to result in sexual selection interactions that drive the evolution of internal reproductive components in both sexes. Our results and discussion of the literature highlight the importance of considering internal soft structures that may influence fertilisation, when investigating selective forces acting on the evolution of reproductive traits.     

Immune Responses Elicited in Tertiary Lymphoid Tissues Display Distinctive Features

During chronic inflammation, immune effectors progressively organize themselves into a functional tertiary lymphoid tissue (TLT) within the targeted organ. TLT has been observed in a wide range of chronic inflammatory conditions but its pathophysiological significance remains unknown. We used the rat aortic interposition model in which a TLT has been evidenced in the adventitia of chronically rejected allografts one month after transplantation. The immune responses elicited in adventitial TLT and those taking place in spleen and draining lymph nodes (LN) were compared in terms of antibody production, T cell activation and repertoire perturbations. The anti-MHC humoral response was more intense and more diverse in TLT. This difference was associated with an increased percentage of activated CD4+ T cells and a symmetric reduction of regulatory T cell subsets. Moreover, TCR repertoire perturbations in TLT were not only increased and different from the common pattern observed in spleen and LN but also “stochastic,” since each recipient displayed a specific pattern. We propose that the abnormal activation of CD4+ T cells promotes the development of an exaggerated pathogenic immune humoral response in TLT. Preliminary findings suggest that this phenomenon i) is due to a defective immune regulation in this non-professional inflammatory-induced lymphoid tissue, and ii) also occurs in human chronically rejected grafts.     

Proteomic analysis of the autoantibody response following immunization with a single autoantigen

In most autoimmune diseases, the autoantibody response is directed against several antigens of the target organ whose identification is crucial for understanding the physiopathological process. Thus, technologies allowing a characterization of the whole autoantibody pattern of both human and experimental autoimmune diseases are required. Here we have used immunoproteomic analysis of human epidermal extracts to characterize the diversity of the anti-desmosome antibody response induced in normal mice immunized with desmoglein 1, the major autoantigen of pemphigus foliaceus, an autoimmune blistering skin disease. In particular, this analysis enables us to characterize the binding properties of anti-desmosome mAbs derived from these mice and to show that the autoantibody response induced upon immunization with a single autoantigen targets different epidermal autoantigens with a pattern similar to that observed in certain variety of human pemphigus.     

Incorporating allelic variation for reconstructing the evolutionary history of organisms from multiple genes: An example from Rosa in North America

Allelic variation within individuals holds information regarding the relationships of organisms, which is expected to be particularly important for reconstructing the evolutionary history of closely related taxa. However, little effort has been committed to incorporate such information for reconstructing the phylogeny of organisms. Haplotype trees represent a solution when one nonrecombinant marker is considered, but there is no satisfying method when multiple genes are to be combined. In this paper, we propose an algorithm that converts a distance matrix of alleles to a distance matrix among organisms. This algorithm allows the incorporation of allelic variation for reconstructing the phylogeny of organisms from one or more genes. The method is applied to reconstruct the phylogeny of the seven native diploid species of Rosa sect. Cinnamomeae in North America. The glyceralgehyde 3-phosphate dehydrogenase (GAPDH), the triose phosphate isomerase (TPI), and the malate synthase (MS) genes were sequenced for 40 individuals from these species. The three genes had little genetic variation, and most species showed incomplete lineage sorting, suggesting these species have a recent origin. Despite these difficulties, the networks (NeighborNet) of organisms reconstructed from the matrix obtained with the algorithm recovered groups that more closely match taxonomic boundaries than did the haplotype trees. The combined network of individuals shows that species west of the Rocky Mountains, Rosa gymnocarpa and R. pisocarpa, form exclusive groups and that together they are distinct from eastern species. In the east, three groups were found to be exclusive: R. nitida-R. palustris, R. foliolosa, and R. blanda-R. woodsii. These groups are congruent with the morphology and the ecology of species. The method is also useful for representing hybrid individuals when the relationships are reconstructed using a phylogenetic network.     

Recovery of viable cells from rabbit skin biopsies after storage at ?20°C for up to 10?days

Frozen animal tissues are thought to be appropriate for use as a donor for somatic cell nuclear transfer. This makes the freezing for long term storage a valuable tool for breeders needing to protect an animal population that is endangered by sanitary problems or for cryobanking of genetic resources. We report the successful cryopreservation of explants of skin derived from small biopsies from rabbit ear biopsies by using a protocol that can be easily performed by usual breeders, which are not equipped with cooling devices. By optimizing the procedure, we show that small biopsies can be kept at -20°C in a physiological solution containing 10% DMSO for up to 20 days before being deeply frozen in liquid nitrogen for long-term storage. After 10 days of storage at -20°C, the rate of viability of biopsies was similar to the control one (86 and 82% respectively). After 20 days of storage at -20°C, the rate of viability was dramatically lowered (39%), but it still allows to recover a significant population of viable cells from the preserved sample. Being appropriate to places lacking specific device, such a very simple technique may contribute to facilitate genome banking policies dedicated to the management of genetic resources in wild and domestic animals.     

Quantification of angiogenesis in estrogen receptor-positive and negative breast carcinoma

Background

The objective of this study was to evaluate angiogenesis according to CD34 antigen expression in estrogen receptor (ER)-positive and negative breast carcinomas.

Methods

This study comprised 64 cases of infiltrating ductal carcinoma in postmenopausal women divided into two groups: Group A: ER-positive, n = 35; and Group B: ER-negative, n = 29. The anti-CD34 monoclonal antibody was used as a marker for endothelial cells. Microvessel count was carried out in 10 fields per slide using a 40× objective lens (magnification 400×). Statistical analysis of the data was performed using Student's t-test (p < 0.05).

Results

The mean number of vessels stained with the anti-CD34 antibody in the estrogen receptor-positive and negative tumors was 23.51 ± 1.15 and 40.24 ± 0.42, respectively. The number of microvessels was significantly greater in the estrogen receptor-negative tumors (p < 0.001).

Conclusion

ER-negative tumors have significantly greater CD34 antigen expression compared to ER-positive tumors.

     

Evolution of triploidy in Apios americana (Leguminosae) revealed by genealogical analysis of the histone H3-D gene

Autotriploidy is normally considered to be maladaptive in plants because of its association with high levels of sterility. Nonetheless, triploid individuals are found in many plant species and play important roles in plant evolution, in particular as a first step toward tetraploid formation. However, few studies have addressed the evolutionary potential of triploid lineages, which may principally suffer from the impossibility of combining useful mutations in a single genome due to their low fertility. Therefore, triploids acquire genetic diversity only via recurrent evolution and somaclonal mutation. This study evaluates the potential of multiple origins of polyploidy as a source of genetic diversity in Apios americana, a North American legume that possesses both diploid and triploid populations. Ploidy level determination via flow cytometry shows that triploids are mainly restricted to the portion of eastern North America that was covered by ice during the Wisconsinan glaciation 18,000 years ago. This distribution implies that either selection or postglaciation colonization played a role in shaping this cytogeographic pattern. A haplotype network of the single copy nuclear histone H3-D gene reconstructed using statistical parsimony, together with single-strand conformational polymorphism analysis, shows that autotriploidy evolved at least three times in this species and that heterozygosity is high in triploids. The genetic diversity found in A. americana resulting from recurrent evolution and fixed heterozygosity increases the likelihood of producing successful genotypes and may give the opportunity for triploids to be better fit than diploids in new habitats. This suggests that triploid lineages can exhibit evolutionary potential of their own, and do not serve solely as a first step toward tetraploid formation.