Nephrotic syndrome, a malfunction of the kidney glomerular filter, leads to proteinuria, edema and, in steroid-resistant nephrotic syndrome, end-stage kidney disease. Using positional cloning, we identified mutations in the phospholipase C epsilon gene (PLCE1) as causing early-onset nephrotic syndrome with end-stage kidney disease. Kidney histology of affected individuals showed diffuse mesangial sclerosis (DMS). Using immunofluorescence, we found PLCepsilon1 expression in developing and mature glomerular podocytes and showed that DMS represents an arrest of normal glomerular development. We identified IQ motif-containing GTPase-activating protein 1 as a new interaction partner of PLCepsilon1. Two siblings with a missense mutation in an exon encoding the PLCepsilon1 catalytic domain showed histology characteristic of focal segmental glomerulosclerosis. Notably, two other affected individuals responded to therapy, making this the first report of a molecular cause of nephrotic syndrome that may resolve after therapy. These findings, together with the zebrafish model of human nephrotic syndrome generated by plce1 knockdown, open new inroads into pathophysiology and treatment mechanisms of nephrotic syndrome.

A properly established and maintained podocyte intercellular junction, or slit diaphragm, is a necessary component of the selective permeability barrier of the kidney glomerulus. The observation that mutation or deletion of the slit diaphragm transmembrane protein nephrin results in failure of podocyte foot process morphogenesis and concomitant proteinuria first suggested the hypothesis that nephrin serves as a component of a signaling complex that directly integrates podocyte junctional integrity with cytoskeletal dynamics. The observations made herein provide the first direct evidence to our knowledge for a phosphorylation-mediated signaling mechanism by which this integrative function is derived. Our data support the model that during podocyte intercellular junction formation, engagement of the nephrin ectodomain induces transient Fyn catalytic activity that results in nephrin phosphorylation on specific nephrin cytoplasmic domain tyrosine residues. We found that this nephrin phosphorylation event resulted in recruitment of the SH2-SH3 domain-containing adapter protein Nck and assembly of actin filaments in an Nck-dependent fashion. Considered in the context of the role of nephrin family proteins in other organisms and the integral relationship of actin dynamics and junction formation, these observations establish a function for nephrin in regulating actin cytoskeletal dynamics. IntroductionGlomerular visceral epithelial cells play a central role in maintaining the selective filtration barrier of the renal glomerulus. These cells are also termed podocytes to describe the foot-like appearance of numerous interdigitating foot processes that arise from their cell bodies and surround glomerular capillary walls. Glomerular filtrate passes across the specialized intercellular junction -also termed the slit diaphragm -formed at the interface of these interdigitating foot processes.In response to injury, podocytes undergo a dramatic change in morphology termed foot process effacement resulting from alteration in cytoskeletal and intercellular junctional architecture. By electron microscopy, effacement is manifested by retraction and spreading of podocyte processes. Effacement is a fluid and reversible process that directly correlates with the development of proteinuria both in human disease and in experimental models.The cellular and molecular mechanisms that integrate podocyte morphology and filter integrity are incompletely defined. Recent investigations have focused on identifying and characterizing the interrelationships and functions of the molecular components of the foot process intercellular junction because several of these components are necessary for development of normal podocyte structure and filter integrity (reviewed in refs. 1, 2).

Mutations that cause defects in levels of the signaling lipid phosphatidylinositol 3,5-bisphosphate [PI(3,5)P 2 ] lead to profound neurodegeneration in mice. Moreover, mutations in human FIG4 predicted to lower PI(3,5)P 2 levels underlie Charcot–Marie–Tooth type 4J neuropathy and are present in selected cases of amyotrophic lateral sclerosis. In yeast and mammals, PI(3,5)P 2 is generated by a protein complex that includes the lipid kinase Fab1/Pikfyve, the scaffolding protein Vac14, and the lipid phosphatase Fig4. Fibroblasts cultured from Vac14 −/− and Fig4 −/− mouse mutants have a 50% reduction in the levels of PI(3,5)P 2 , suggesting that there may be PIKfyve-independent pathways that generate this lipid. Here, we characterize a Pikfyve gene-trap mouse ( Pikfyve β -geo/ β -geo ), a hypomorph with ∼10% of the normal level of Pikfyve protein. shRNA silencing of the residual Pikfyve transcript in fibroblasts demonstrated that Pikfyve is required to generate all of the PI(3,5)P 2 pool. Surprisingly, Pikfyve also is responsible for nearly all of the phosphatidylinositol-5-phosphate (PI5P) pool. We show that PI5P is generated directly from PI(3,5)P 2 , likely via 3′-phosphatase activity. Analysis of tissues from the Pikfyve β -geo/ β -geo mouse mutants reveals that Pikfyve is critical in neural tissues, heart, lung, kidney, thymus, and spleen. Thus, PI(3,5)P 2 and PI5P have major roles in multiple organs. Understanding the regulation of these lipids may provide insights into therapies for multiple diseases.

Combination therapy concurrently targeting PD1 and CTLA4 immune checkpoints leads to remarkable anti-tumor effects. While both PD1 and CTLA4 dampen the T cell activation, the in vivo effects of these drugs in humans remain to be clearly defined. In order to better understand biologic effects of therapy, we analyzed blood/tumor tissue from 45 patients undergoing single or combination immune checkpoint blockade. We show that blockade of CTLA4, PD1 or combination of the two leads to distinct genomic and functional signatures in vivo in purified human T cells and monocytes. Therapy-induced changes are more prominent in T cells than in monocytes and involve largely non-overlapping changes in coding genes including alternatively-spliced transcripts, and non-coding RNAs. Pathway analysis revealed that CTLA4-blockade induces a proliferative signature predominantly in a subset of transitional memory T cells, while PD1-blockade instead leads to changes in genes implicated in cytolysis and natural killer cell function. Combination blockade leads to non-overlapping changes in gene expression including proliferation-associated and chemokine genes. These therapies also have differential effects on plasma levels of CXCL10, sIL2R and IL1α. Importantly, PD1 receptor occupancy following anti-PD1 therapy may be incomplete in the tumor T cells even in the setting of complete receptor occupancy in circulating T cells. These data demonstrate that in spite of shared property of checkpoint blockade, antibodies against PD1, CTLA4 alone or in combination have distinct immunologic effects in vivo. Improved understanding of pharmacodynamic effects of these agentsin patients will support rational development of immune-based combinations against cancer.

Recent investigations have focused on characterizing the molecular components of the podocyte intercellular junction, because several of these components, including Nephrin, are functionally necessary for development of normal podocyte structure and filter integrity. Accumulating evidence suggests that the Nephrin-associated protein complex is a signaling nexus.

As a putative cell adhesion molecule of the immunoglobulin superfamily, nephrin likely participates in cell-cell interactions between podocyte foot processes and may represent a component of the slit diaphragm.

and rate of rise ofmelanoma mortality are known. One group is then subjected to educational material to which the control group is not exposed and changing patterns of presentation and mortality compared in the two groups. Although this is what was originally planned in Scotland, it was quickly apparent that television was by far the most powerful educational medium, and television channels are relatively unrestricted in their distribution. Furthermore, a story regarded as newsworthy in one area is quickly publicised by television, radio, and newspapers in adjacent areas. In addition, organisers of campaigns such as this have no control over the spread of information in the secondary wave of publicity in women's magazines, etc. Thus, although not ideal, it was necessary to accept the compromise of changes in thickness and mortality in the intervention group before and after intervention as a reasonable measure of efficacy. ConclusionIn conclusion, audit of the west of Scotland melanoma education campaign shows encouraging evidence that for women the appropriate population has been targeted and patients are now attending for treatment with thinner primary melanomas. The number of thick melanomas diagnosed in women and the melanoma related mortality in women both showed a downward trend. Alternative approaches seem to be needed to achieve a similar result in men. Abstract Objective-To test whether a fat reduced diet rich in soluble dietary fibre, antioxidant vitamins, and minerals reduces complications and mortality after acute myocardial infarction.

While the mechanisms that regulate actin dynamics in cellular motility are intensively studied, relatively little is known about signaling events that transmit outside-in signals and direct assembly and regulation of actin polymerization complexes at the cell membrane. The kidney podocyte provides a unique model for investigating these mechanisms since deletion of Nephrin or Neph1, two interacting components of the specialized podocyte intercellular junction, results in abnormal podocyte morphogenesis and junction formation. We provide evidence that extends the existing model by which the Nephrin-Neph1 complex transduces phosphorylation-mediated signals that assemble an actin polymerization complex at the podocyte intercellular junction. Upon engagement, Neph1 is phosphorylated on specific tyrosine residues by Fyn, which results in the recruitment of Grb2, an event that is necessary for Neph1-induced actin polymerization at the plasma membrane. Importantly, Neph1 and Nephrin directly interact and, by juxtaposing Grb2 and Nck1/2 at the membrane following complex activation, cooperate to augment the efficiency of actin polymerization. These data provide evidence for a mechanism reminiscent of that employed by vaccinia virus and other pathogens, by which a signaling complex transduces an outside-in signal that results in actin filament polymerization at the plasma membrane.Precisely regulated actin polymerization provides the motive force necessary for intercellular junction formation and contributes to defining the shape and polarity of the cell. Similarly, directed actin polymerization proximate to the leading edge of the plasma membrane drives cell motility and is required in the complicated dynamics of lamellipodia, filopodia, and other specialized membrane structures including invadopodia and podosomes (6). While substantial progress has been made in understanding the cellular and molecular mechanisms that determine actin dynamics in these model systems (32), less is known about membrane-based proximal signaling events that transmit outside-in signals and direct assembly and regulation of actin polymerization complexes at these sites.Kidney glomerular visceral epithelial cells or podocytes are necessary for maintaining the glomerular filtration barrier (reviewed in reference 20). When mature, these cells have a unique octopus-like structure comprised of a central cell body that gives off branching primary, secondary, and tertiary processes. The tertiary processes or "foot processes" attach the podocyte to the glomerular capillary basement membrane, where they surround the glomerular capillary and where they interdigitate to form a specialized intercellular junction called the "slit diaphragm." Here foot processes provide a necessary element of the permeability-selective glomerular filter, allowing passage of water, solutes, and other small macromolecules from the capillary lumen to the urinary space while restricting the flux of cells and larger macromolecules.The podocyte provides a unique model for investiga...