Inhibiting the urokinase‐type plasminogen activator receptor system recovers STZ‐induced diabetic nephropathy

The urokinase‐type plasminogen activator (uPA) receptor (uPAR) participates to the mechanisms causing renal damage in response to hyperglycaemia. The main function of uPAR in podocytes (as well as soluble uPAR ‐(s)uPAR‐ from circulation) is to regulate podocyte function through αvβ3 integrin/Rac‐1. We addressed the question of whether blocking the uPAR pathway with the small peptide UPARANT, which inhibits uPAR binding to the formyl peptide receptors (FPRs) can improve kidney lesions in a rat model of streptozotocin (STZ)‐induced diabetes. The concentration of systemically administered UPARANT was measured in the plasma, in kidney and liver extracts and UPARANT effects on dysregulated uPAR pathway, αvβ3 integrin/Rac‐1 activity, renal fibrosis and kidney morphology were determined. UPARANT was found to revert STZ‐induced up‐regulation of uPA levels and activity, while uPAR on podocytes and (s)uPAR were unaffected. In glomeruli, UPARANT inhibited FPR2 expression suggesting that the drug may act downstream uPAR, and recovered the increased activity of the αvβ3 integrin/Rac‐1 pathway indicating a major role of uPAR in regulating podocyte function. At the functional level, UPARANT was shown to ameliorate: (a) the standard renal parameters, (b) the vascular permeability, (c) the renal inflammation, (d) the renal fibrosis including dysregulated plasminogen‐plasmin system, extracellular matrix accumulation and glomerular fibrotic areas and (e) morphological alterations of the glomerulus including diseased filtration barrier. These results provide the first demonstration that blocking the uPAR pathway can improve diabetic kidney lesion in the STZ model, thus suggesting the uPA/uPAR system as a promising target for the development of novel uPAR‐targeting approaches.     

DR antigen expression on ovarian carcinoma cells does not correlate with their capacity to elicit an autologous proliferative response

Summary Expression of HLA-DR antigens by purified preparations of human ovarian carcinoma cells freshly isolated from surgical specimens was examined in parallel with the capacity of tumor cells to elicit a blastogenic response from autologous lymphocytes in mixed lymphocyte-tumor culture (MLTC) assay. Of 21 tumor preparations, 11 (52%) reacted with monoclonal antibodies 279 and/or 949 specific for a monomorphic determinant of HLA-DR antigens, with heterogeneous positivity, ranging between 30% and 95%. In this series of patients positive MLTC occurred in 8/21 individual experiments. The HLA-DR expression was proportionally similar in tumors giving positive MLTC (4/8=50%) and negative MLTC (7/13=53%). The lack of correlation between DR expression on tumor cells and stimulatory activity in autologous MLTC and the fact that DR-negative tumors could induce lymphocyte stimulation, support the hypothesis that blastogenesis occurs upon recognition of tumor-associated antigens, different from DR molecules, possibly tumor-specific antigens.     

When size does matter: organelle size influences the properties of transport mediated by molecular motors

Background

Organelle transport is driven by the action of molecular motors. In this work, we studied the dynamics of organelles of different sizes with the aim of understanding the complex relation between organelle motion and microenvironment.

Methods

We used single particle tracking to obtain trajectories of melanosomes (pigmented organelles in Xenopus laevis melanophores). In response to certain hormones, melanosomes disperse in the cytoplasm or aggregate in the perinuclear region by the combined action of microtubule and actin motors.

Results and conclusions

Melanosome trajectories followed an anomalous diffusion model in which the anomalous diffusion exponent (α) provided information regarding the trajectories' topography and thus of the processes causing it. During aggregation, the directionality of big organelles was higher than that of small organelles and did not depend on the presence of either actin or intermediate filaments (IF). Depolymerization of IF significantly reduced α values of small organelles during aggregation but slightly affect their directionality during dispersion.

General significance

Our results could be interpreted considering that the number of copies of active motors increases with organelle size. Transport of big organelles was not influenced by actin or IF during aggregation showing that these organelles are moved processively by the collective action of dynein motors. Also, we found that intermediate filaments enhance the directionality of small organelles suggesting that this network keeps organelles close to the tracks allowing their efficient reattachment. The higher directionality of small organelles during dispersion could be explained considering the better performance of kinesin-2 vs. dynein at the single molecule level.     

Males with a Faster Courtship Display have More White Spots and Higher Pairing Success in the Diamond Firetail,Stagonopleura guttata

There is growing evidence that female mate choice could be based on a combination of multiple signals that often involve both ornamental colourful traits and behavioural displays. The Diamond Firetail is an Australian finch with a variable number of white spots on their black flank feathers. The number of white spots is a dimorphic characteristic: females have more spots than males, and males prefer females with many spots. Previously, we found assortative pairing for spot number despite the absence of experimental evidence for female preference for male spot number. Here, we test whether the male behavioural courtship display (bobbing while waving a grass stem) correlates with male spot number and pairing success. We also test whether male spot number predicts the outcome (winner or loser) of intrasexual competition over courtship materials (grass stem, perch, nest site). Males with many spots had higher pairing success, and male spot number correlated with the intensity of courtship display. In a multivariate statistical analysis, male courtship display was the stronger predictor of male pairing success. Finally, male spot number predicted the outcome of intrasexual interactions: males with many spots consistently won contests over grass stems, perches and nest sites. We suggest that intrasexual selection could favour male spot number, whereas courtship intensity appears to be under stronger intersexual selection.     

The Vitamin D Receptor Agonist BXL-01-0029 as a Potential New Pharmacological Tool for the Treatment of Inflammatory Myopathies

Objective

This study aims to investigate in vitro the effect of the VDR agonist BXL-01-0029 onto IFNγ/TNFα-induced CXCL10 secretion by human skeletal muscle cells compared to elocalcitol (VDR agonist), methylprednisolone, methotrexate, cyclosporin A, infliximab and leflunomide; to assess in vivo circulating CXCL10 level in subjects at time of diagnosis with IMs, before therapy, together with TNFα, IFNγ, IL-8, IL-6, MCP-1, MIP-1β and IL-10, vs. healthy subjects.

Methods

Human fetal skeletal muscle cells were used for in vitro studies; ELISA and Bio-Plex were used to measure cell supernatant and IC₅₀ determination or serum cytokines; Western blot and Bio-Plex were for cell signaling analysis.

Results

BXL-01-0029 decreased with the highest potency IFNγ/TNFα-induced CXCL10 protein secretion and targeted cell signaling downstream of TNFα in human skeletal muscle cells; CXCL10 level was the highest in sera of subjects diagnosed with IMs before therapy and the only one significantly different vs. healthy controls.

Conclusions

Our in vitro and in vivo data, while confirm the relevance of CXCL10 in IMs, suggested BXL-01-0029 as a novel pharmacological tool for IM treatment, hypothetically to be used in combination with the current immunosuppressants to minimize side effects.     

Pharmacological blockade of mGlu2/3 metabotropic glutamate receptors reduces cell proliferation in cultured human glioma cells

Glial cell proliferation in culture is under the control of metabotropic glutamate (mGlu) receptors. We have examined whether this control extends to human glioma cells. Primary cultures were prepared from surgically removed human glioblastomas. RT-PCR combined with western blot analysis showed that most of the cultures (eight out of 11) expressed group-II mGlu receptors. In two selected cultures (MZC-12 and FCN-9), the mGlu2/3 receptor antagonist, LY341495, slowed cell proliferation when applied to the growth medium from the second day after plating. This effect was reversible because linear cell growth was restored after washing out the drug. LY341495 reduced glioma cell proliferation at concentrations lower than 100 nm, which are considered as selective for mGlu2/3 receptors. In addition, its action was mimicked by the putative mGlu2/3 receptor antagonist (2S)-alpha-ethylglutamate. The anti-proliferative effect of LY341495 was confirmed by measuring [methyl-3H]-thymidine incorporation in cultures arrested in G0 phase of the cell cycle and then stimulated to proliferate by the addition of 10% fetal calf serum or 100 ng/mL of epidermal growth factor (EGF). In cultures treated with EGF, LY341495 was also able to reduce the stimulation of the mitogen-activated protein kinase (MAPK) pathway, as well as the induction of cyclin D1. Both effects, as well as decreased [methyl-3H]-thymidine incorporation, were partially reduced by co-addition of the potent mGlu2/3 receptor agonist, LY379268. We conclude that activation of group-II mGlu receptors supports the growth of human glioma cells in culture and that antagonists of these receptors should be tested for their ability to reduce tumour growth in vivo.     

From chronic kidney disease to transplantation: the roles of obestatin

This study was designed to investigate the possible effect of sitagliptin on renal damage induced by renal ischemia reperfusion (I/R) in diabetic rats. T2DM in rats was induced by the administration of nicotinamide (230 mg/kg, i.p.), 15 min prior to a single dose of streptozotocin (65 mg/kg, i.v.). In vivo renal I/R was performed in both T2DM and normal rats. Each protocol comprised ischemia for 30 min followed by reperfusion for 24 h and a treatment period of 14 days before induction of ischemia. Sitagliptin treated diabetic rats that underwent renal I/R demonstrated significant decrease in the serum concentrations of aspartate aminotransferase (p < 0.01), urea nitrogen (p < 0.01) and creatinine (p < 0.001) compared to renal I/R in diabetic rats. Lipid peroxidation, xanthine oxidase activity, myeloperoxidase activity and nitric oxide level in renal tissue were significantly (p < 0.05, p < 0.001, p < 0.01, p < 0.05 respectively) decreased after renal I/R in sitagliptin treated rats compared to diabetic rats. Antioxidant enzymes like glutathione (p < 0.05), glutathione peroxidase (p < 0.001), superoxide dismutase (p < 0.05) and catalase (p < 0.001) were significantly increased after renal I/R in sitagliptin treated diabetic rats compared to non treated diabetic rats. The typical DNA laddering was observed when renal I/R performed in diabetic rats, which indicates cell apoptosis. Sitagliptin treated rats demonstrated a decrease in DNA fragmentation and apoptosis. Furthermore, renal histopathology preserved in sitagliptin treated rats verified protection against renal I/R in diabetes. The results of present investigation established sitagliptin treatment attenuated renal damage induced by renal I/R in diabetic rats.     

Communicative interactions improve visual detection of biological motion

Background

In the context of interacting activities requiring close-body contact such as fighting or dancing, the actions of one agent can be used to predict the actions of the second agent [1]. In the present study, we investigated whether interpersonal predictive coding extends to interactive activities – such as communicative interactions - in which no physical contingency is implied between the movements of the interacting individuals.

Methodology/Principal Findings

Participants observed point-light displays of two agents (A and B) performing separate actions. In the communicative condition, the action performed by agent B responded to a communicative gesture performed by agent A. In the individual condition, agent A''s communicative action was substituted with a non-communicative action. Using a simultaneous masking detection task, we demonstrate that observing the communicative gesture performed by agent A enhanced visual discrimination of agent B.

Conclusions/Significance

Our finding complements and extends previous evidence for interpersonal predictive coding, suggesting that the communicative gestures of one agent can serve as a predictor for the expected actions of the respondent, even if no physical contact between agents is implied.