Activation of Rac-1 and RhoA Contributes to Podocyte Injury in Chronic Kidney Disease

Rho-family GTPases like RhoA and Rac-1 are potent regulators of cellular signaling that control gene expression, migration and inflammation. Activation of Rho-GTPases has been linked to podocyte dysfunction, a feature of chronic kidney diseases (CKD). We investigated the effect of Rac-1 and Rho kinase (ROCK) inhibition on progressive renal failure in mice and studied the underlying mechanisms in podocytes. SV129 mice were subjected to 5/6-nephrectomy which resulted in arterial hypertension and albuminuria. Subgroups of animals were treated with the Rac-1 inhibitor EHT1846, the ROCK inhibitor SAR407899 and the ACE inhibitor Ramipril. Only Ramipril reduced hypertension. In contrast, all inhibitors markedly attenuated albumin excretion as well as glomerular and tubulo-interstitial damage. The combination of SAR407899 and Ramipril was more effective in preventing albuminuria than Ramipril alone. To study the involved mechanisms, podocytes were cultured from SV129 mice and exposed to static stretch in the Flexcell device. This activated RhoA and Rac-1 and led via TGFβ to apoptosis and a switch of the cells into a more mesenchymal phenotype, as evident from loss of WT-1 and nephrin and induction of α-SMA and fibronectin expression. Rac-1 and ROCK inhibition as well as blockade of TGFβ dramatically attenuated all these responses. This suggests that Rac-1 and RhoA are mediators of podocyte dysfunction in CKD. Inhibition of Rho-GTPases may be a novel approach for the treatment of CKD.     

Detection of phytochrome-like genes from Rhazya stricta (Apocynaceae) using de novo genome assembly

Phytochrome-like genes in the wild plant species Rhazya stricta Decne were characterized using a de novo genome assembly of next generation sequence data. Rhazya stricta contains more than 100 alkaloids with multiple pharmacological properties, and leaf extracts have been used to cure chronic rheumatism, to treat tumors, and in the treatment of several other diseases. Phytochromes are known to be involved in the light-regulated biosynthesis of some alkaloids. Phytochromes are soluble chromoproteins that function in the absorption of red and far-red light and the transduction of intracellular signals during light-regulated plant development. De novo assembly of the nuclear genome of R. stricta recovered 45,641 contigs greater than 1000 bp long, which were used in constructing a local database. Five sequences belonging to Arabidopsis thaliana phytochrome gene family (i.e., AtphyABCDE) were used to identify R. stricta contigs with phytochrome-like sequences using BLAST. This led to the identification of three contigs with phytochrome-like sequences covering AtphyA-, AtphyC- and AtphyE-like full-length genes. Annotation of the three sequences showed that each contig consists of one phytochrome-like gene with three exons and two introns. BLASTn and BLASTp results indicated that RsphyA mRNA and protein sequences had homologues in Wrightia coccinea and and Solanum tuberosum, respectively. RsphyC-like mRNA and protein sequence were homologous to Vitis vinifera and Vitis riparia. RsphyE-like mRNA coding and protein sequences were homologous to Ipomoea nil. Multiple-sequence alignment of phytochrome proteins indicated a homology with 30 sequences from 23 different species of flowering plants. Phylogenetic analysis confirmed that each R. stricta phytochrome gene is related to the same phytochrome gene of other flowering plants. It is proposed that the absence of phyB gene in R. stricta is due to RsphyA gene taking over the role of phyB.     

The Development of the Older Persons and Informal Caregivers Survey Minimum DataSet (TOPICS-MDS): A Large-Scale Data Sharing Initiative

Introduction

In 2008, the Ministry of Health, Welfare and Sport commissioned the National Care for the Elderly Programme. While numerous research projects in older persons’ health care were to be conducted under this national agenda, the Programme further advocated the development of The Older Persons and Informal Caregivers Survey Minimum DataSet (TOPICS-MDS) which would be integrated into all funded research protocols. In this context, we describe TOPICS data sharing initiative (www.topics-mds.eu).

Materials and Methods

A working group drafted TOPICS-MDS prototype, which was subsequently approved by a multidisciplinary panel. Using instruments validated for older populations, information was collected on demographics, morbidity, quality of life, functional limitations, mental health, social functioning and health service utilisation. For informal caregivers, information was collected on demographics, hours of informal care and quality of life (including subjective care-related burden).

Results

Between 2010 and 2013, a total of 41 research projects contributed data to TOPICS-MDS, resulting in preliminary data available for 32,310 older persons and 3,940 informal caregivers. The majority of studies sampled were from primary care settings and inclusion criteria differed across studies.

Discussion

TOPICS-MDS is a public data repository which contains essential data to better understand health challenges experienced by older persons and informal caregivers. Such findings are relevant for countries where increasing health-related expenditure has necessitated the evaluation of contemporary health care delivery. Although open sharing of data can be difficult to achieve in practice, proactively addressing issues of data protection, conflicting data analysis requests and funding limitations during TOPICS-MDS developmental phase has fostered a data sharing culture. To date, TOPICS-MDS has been successfully incorporated into 41 research projects, thus supporting the feasibility of constructing a large (>30,000 observations), standardised dataset pooled from various study protocols with different sampling frameworks. This unique implementation strategy improves efficiency and facilitates individual-level data meta-analysis.     

Smoking among Shift Workers: More Than a Confounding Factor

In studies on the cardiovascular disease risk among shift workers, smoking is considered to be a confounding factor. In a study of 239 shift and 157 daytime workers, it was found that shift work was prospectively related to increased cigarette consumption, indicating that smoking might be in the causative pathway; however, the number of study subjects was too low to warrant sound conclusions. Therefore, data from the Maastricht Cohort study were used to investigate the longitudinal relation between smoking and shift work in a much larger population. In this study, a total of 12,140 employees were followed for two years by means of self‐administered questionnaires. The authors compared workers who normally worked during daytime hours only (74%) with those who worked other than day shifts (26%). Logistic regression analyses were performed, adjusting for demographic factors of age, gender, and educational level to evaluate the risk of starting to smoke (n=25) in the group of non‐smoking workers and the risk of quitting (n=318) in the group of smoking workers. Logistic regression analysis showed a significant association between shift work and taking up smoking during the two‐year follow‐up (odds ratio: 1.46, p=0.03). The risk to stop smoking was somewhat lower in shift workers (odds ratio: 0.91) but not statistically significant (p=0.5). To conclude, this study showed that, independent of educational level, shift workers are more prone to start smoking. This finding might have important implications for studies on the health effects of shift workers and for possible interventions aimed at the reduction of the excess health risk among shift workers.     

Wood usage and its influence on the environment from the Neolithic until the Iron Age: a case study of the graves at Flintbek (Schleswig–Holstein, Northern Germany)

The investigated area near Flintbek (Schleswig–Holstein, Northern Germany) was used as a burial ground from the Neolithic until the Iron Age. Due to modern agriculture, the above-ground funerary monuments have been destroyed. Rescue excavations from 1976 to 1996 recovered the archaeological remains. In addition to the archaeological reassessment of the findings, further scientific analyses were carried out. The results of the charcoal analyses are presented in this paper. The overall spectrum of wood species represents the typical species composition of mixed oak forests. Over the whole investigated time span (Neolithic–Iron Age) these species alternate with a second group of taxa: species benefiting from better light conditions. In times of intensive human impact, these light-demanding taxa gained considerable importance, showing the opening of the wooded landscape. In phases with less human impact, a regeneration of mixed oak forest is detectable. For the Neolithic it was possible to develop a more detailed picture of wood usage based on 162 radiocarbon dates of 106 samples. These illustrate considerable changes during the Neolithic, which resulted in a varied pattern of open land and closed forest influenced by human presence and land use. Another important aspect of the Flintbek area is the handling of samples deriving from different contexts. While charcoal samples related to fire usage or grave constructions contain only slight contamination, samples from fillings (pits, burial layers) are characterized by charcoal dating being either too old or even too young for the archaeological context.     

Long‐distance dispersal maximizes evolutionary potential during rapid geographic range expansion

Conventional wisdom predicts that sequential founder events will cause genetic diversity to erode in species with expanding geographic ranges, limiting evolutionary potential at the range margin. Here, we show that invasive European starlings (Sturnus vulgaris) in South Africa preserve genetic diversity during range expansion, possibly as a result of frequent long‐distance dispersal events. We further show that unfavourable environmental conditions trigger enhanced dispersal, as indicated by signatures of selection detected across the expanding range. This brings genetic variation to the expansion front, counterbalancing the cumulative effects of sequential founding events and optimizing standing genetic diversity and thus evolutionary potential at range margins during spread. Therefore, dispersal strategies should be highlighted as key determinants of the ecological and evolutionary performances of species in novel environments and in response to global environmental change.     

Living in a dangerous world decreases maternal care: a study in serotonin transporter knockout mice

Adverse early experiences can profoundly influence the adult behavioral profile. When pregnant and lactating mice are confronted with soiled bedding of unfamiliar males (UMB), these stimuli signal the danger of infanticide and thus simulate a “dangerous world”. In a previous study, offspring of UMB treated mothers were shown to display increased anxiety-like behavior and reduced exploratory locomotion as adults, compared to mice treated with neutral bedding (NB, “safe environment”). The aim of this study was to elucidate the mechanisms conveying these effects of living in a “dangerous world” to offspring behavior. We hypothesized the mother to be the major link and focused on the influence of UMB on maternal stress hormones and behavior. Thus, we investigated fecal corticosterone metabolites (CM) and maternal care of pregnant and lactating mice either treated with NB or UMB. The offspring were subsequently tested for their anxiety-like and exploratory behavior. Mothers treated with UMB showed a significantly higher increase of fecal CM following the initial treatment, than NB treated mothers, indicating that the odor cues of potentially infanticidal males represented an ethologically relevant stimulus. Whereas the hormonal stress response habituated, living in a “dangerous world” led to a distinct and consistent reduction of maternal care behavior, particularly concerning the duration of licking and grooming the pups. Surprisingly, we could not confirm our former findings of altered phenotypes in the offspring of UMB treated mothers. In summary, we hypothesize that the frequently described effects of early life adversity on the offspring's behavioral profile are mediated primarily by maternal care in altricial rodents.     

Automated analysis of three-dimensional xylem networks using high-resolution computed tomography

Connections between xylem vessels represent important links in the vascular network, but the complexity of three-dimensional (3D) organization has been difficult to access. This study describes the development of a custom software package called TANAX (Tomography-derived Automated Network Analysis of Xylem) that automatically extracts vessel dimensions and the distribution of intervessel connections from high-resolution computed tomography scans of grapevine (Vitis vinifera) stems, although the method could be applied to other species. Manual and automated analyses of vessel networks yielded similar results, with the automated method generating orders of magnitude more data in a fraction of the time. In 4.5-mm-long internode sections, all vessels and all intervessel connections among 115 vessels were located, and the connections were analyzed for their radial distribution, orientation, and predicted shared wall area. Intervessel connections were more frequent in lateral than in dorsal/ventral zones. The TANAX-reconstructed network, in combination with commercial software, was used to visualize vessel networks in 3D. The 3D volume renderings of vessel networks were freely rotated for observation from any angle, and the 4.5?μm virtual serial sections were capable of being viewed in any plane, revealing aspects of vessel organization not possible with traditional serial sections.