Neurolysin Knockout Mice Generation and Initial Phenotype Characterization

The oligopeptidase neurolysin (EC 3.4.24.16; Nln) was first identified in rat brain synaptic membranes and shown to ubiquitously participate in the catabolism of bioactive peptides such as neurotensin and bradykinin. Recently, it was suggested that Nln reduction could improve insulin sensitivity. Here, we have shown that Nln KO mice have increased glucose tolerance, insulin sensitivity, and gluconeogenesis. KO mice have increased liver mRNA for several genes related to gluconeogenesis. Isotopic label semiquantitative peptidomic analysis suggests an increase in specific intracellular peptides in gastrocnemius and epididymal adipose tissue, which likely is involved with the increased glucose tolerance and insulin sensitivity in the KO mice. These results suggest the exciting new possibility that Nln is a key enzyme for energy metabolism and could be a novel therapeutic target to improve glucose uptake and insulin sensitivity.     

Screening for Vulnerability in Older Cancer Patients: The ONCODAGE Prospective Multicenter Cohort Study

Background

Geriatric Assessment is an appropriate method for identifying older cancer patients at risk of life-threatening events during therapy. Yet, it is underused in practice, mainly because it is time- and resource-consuming. This study aims to identify the best screening tool to identify older cancer patients requiring geriatric assessment by comparing the performance of two short assessment tools the G8 and the Vulnerable Elders Survey (VES-13).

Patients and Methods

The diagnostic accuracy of the G8 and the (VES-13) were evaluated in a prospective cohort study of 1674 cancer patients accrued before treatment in 23 health care facilities. 1435 were eligible and evaluable. Outcome measures were multidimensional geriatric assessment (MGA), sensitivity (primary), specificity, negative and positive predictive values and likelihood ratios of the G8 and VES-13, and predictive factors of 1-year survival rate.

Results

Patient median age was 78.2 years (70-98) with a majority of females (69.8%), various types of cancer including 53.9% breast, and 75.8% Performance Status 0-1. Impaired MGA, G8, and VES-13 were 80.2%, 68.4%, and 60.2%, respectively. Mean time to complete G8 or VES-13 was about five minutes. Reproducibility of the two questionnaires was good. G8 appeared more sensitive (76.5% versus 68.7%, P =  0.0046) whereas VES-13 was more specific (74.3% versus 64.4%, P<0.0001). Abnormal G8 score (HR = 2.72), advanced stage (HR = 3.30), male sex (HR = 2.69) and poor Performance Status (HR = 3.28) were independent prognostic factors of 1-year survival.

Conclusion

With good sensitivity and independent prognostic value on 1-year survival, the G8 questionnaire is currently one of the best screening tools available to identify older cancer patients requiring geriatric assessment, and we believe it should be implemented broadly in daily practice. Continuous research efforts should be pursued to refine the selection process of older cancer patients before potentially life-threatening therapy.     

Steady-state mycophenolate mofetil pharmacokinetic parameters enable prediction of systemic lupus erythematosus clinical flares: an observational cohort study

Introduction  

The aim of this study was to determine whether mycophenolate mofetil (MMF) pharmacokinetics (PK) under combined MMF and prednisone remission-maintenance therapy can predict systemic lupus erythematosus (SLE) clinical flares.     

RAMPs and G protein coupled receptors

RAMPs (receptor activity-modifying proteins) were discovered in 1998 as accessory proteins needed to the functionnal activity of CGRP (calcitonin gene-related peptide) receptors. Three RAMPs generated by three different genes are known in human, rat and mice. The coding sequences of such genes are described, but as yet, regulation sequences are unknown. RAMPs interact with GPCR (G protein-coupled receptors) of class II. In the case of the calcitonin/CGRP peptide family, RAMPs determine the functionnal specificity of the receptor, glycosylate and translocate the receptor to the cell surface. CGRP receptors are observed in presence of the RAMP1/calcitonin receptor-like receptor (CRLR), but the association of RAMP2 or RAMP3 with CRLR generates an adrenomedullin receptor. The calcitonin receptor (CTR) is translocated alone to the cell surface, but interactions of RAMPs with CTR forms amylin receptors. If RAMPs can interact with glucagon, parathyroid hormone and VIP/PACAP (vasoactive intestinal peptide/pituitary adenylate cyclase activating polypeptide (VPACR1)) receptors, the functionnal specificity of these receptors remains unaltered. However, the complex VPACR1/RAMP2 enhances specifically the phosphoinoside signaling pathway.     

Deeper in the human cornea proteome using nanoLC-Orbitrap MS/MS: An improvement for future studies on cornea homeostasis and pathophysiology

The cornea is a transparent, avascular, and highly specialized connective tissue that provides the majority of light refraction in the optical system of the eye. The human cornea is composed of several layers interacting in a complex manner and possessing specific functions, like eye protection and optical clearness. Only few proteomic studies of mammalian cornea have been performed leading to the identification of less than 200 proteins in human corneas. The present study explores the proteome of the intact normal human cornea using a shot-gun nanoLC-MS/MS strategy and an LTQ Orbitrap mass spectrometer. A total of 2070 distinct corneal proteins were identified from five human cornea samples, which represents a 14-fold improvement in the number of proteins identified so far for human cornea. This enlarged dataset of human corneal proteins represents a valuable reference library for further studies on cornea homeostasis and pathophysiology. Network and gene ontology analyses were used to determine biological pathways specific of the human cornea. They allowed the identification of subnetworks of putative importance for corneal diseases, like a redox regulation and oxidative stress network constituted of aldehyde and alcohol dehydrogenases, most of them being described for the first time in human cornea.     

Self assembly of a Fe(L) complex with octacyano metallates [M(CN)8] (L = pentadentate macrocyclic ligand, M = Mo, W): Crystal structure and magnetic properties

The self assembly of [Fe^III(L)]Cl₂ClO₄ (L = pentadentate macrocyclic ligand) with octacyano metallates [M^IV(CN)₈]⁴⁻ (M = Mo, W) leads to bimetallic cyano-bridged 2-D coordination polymers of formula [{Fe(L)}₃{M(CN)₈}₂]Cl·xH₂O with M = Mo (2), or W (3). The structure of the tungsten analogue has been established by single crystal X-ray diffraction. The magnetic properties for both Mo and W derivative are reported.     

In vivo calpain/caspase cross-talk during 3-nitropropionic acid-induced striatal degeneration: implication of a calpain-mediated cleavage of active caspase-3

The role of caspases and calpains in neurodegeneration remains unclear. In this study, we focused on these proteases in a rat model of Huntington's disease using the mitochondrial toxin 3-nitropropionic acid (3NP). Results showed that 3NP-induced death of striatal neurons was preceded by cytochrome c redistribution, transient caspase-9 processing, and activation of calpain, whereas levels of the active/processed form of caspase-3 remained low and were even reduced as compared with control animals. We evidenced here that this decrease in active caspase-3 levels could be attributed to calpain activation. Several observations supported this conclusion. 1) Pharmacological blockade of calpain in 3NP-treated rats increased the levels of endogenous processed caspase-9 and caspase-3. 2) Cell-free extracts prepared from the striatum of 3NP-treated rats degraded in vitro the p34 and p20 subunits of active recombinant caspase-9 and caspase-3, respectively. 3) This degradation of p34 and p20 could be mimicked by purified mu-calpain and was prevented by calpain inhibitors. 4) mu-Calpain produced a loss of the DEVDase (Asp-Glu-Val-Asp) activity of active caspase-3. 5) Western blot analysis and experiments with 35S-radiolabeled caspase-3 showed that mu-calpain cleaved the p20 subunit of active caspase-3 near its catalytic site. 6) mu-Calpain activity was selectively inhibited (IC50 of 100 mum) by a 12 amino acid peptide corresponding to the C terminus of p20. Our results showed that calpain can down-regulate the caspase-9/caspase-3 cell death pathway during neurodegeneration due to chronic mitochondrial defects in vivo and that this effect may involve, at least in part, direct cleavage of the caspase-3 p20 subunit.     

QTLs and candidate genes for desiccation and abscisic acid content in maize kernels

Background

Kernel moisture at harvest is an important trait since a low value is required to prevent unexpected early germination and ensure seed preservation. It is also well known that early germination occurs in viviparous mutants, which are impaired in abscisic acid (ABA) biosynthesis. To provide some insight into the genetic determinism of kernel desiccation in maize, quantitative trait loci (QTLs) were detected for traits related to kernel moisture and ABA content in both embryo and endosperm during kernel desiccation. In parallel, the expression and mapping of genes involved in kernel desiccation and ABA biosynthesis, were examined to detect candidate genes.

Results

The use of an intermated recombinant inbred line population allowed for precise QTL mapping. For 29 traits examined in an unreplicated time course trial of days after pollination, a total of 78 QTLs were detected, 43 being related to kernel desiccation, 15 to kernel weight and 20 to ABA content. Multi QTL models explained 35 to 50% of the phenotypic variation for traits related to water status, indicating a large genetic control amenable to breeding. Ten of the 20 loci controlling ABA content colocated with previously detected QTLs controlling water status and ABA content in water stressed leaves. Mapping of candidate genes associated with kernel desiccation and ABA biosynthesis revealed several colocations between genes with putative functions and QTLs. Parallel investigation via RT-PCR experiments showed that the expression patterns of the ABA-responsive Rab17 and Rab28 genes as well as the late embryogenesis abundant Emb5 and aquaporin genes were related to desiccation rate and parental allele effect. Database searches led to the identification and mapping of two zeaxanthin epoxidase (ZEP) and five novel 9-cis-epoxycarotenoid dioxygenase (NCED) related genes, both gene families being involved in ABA biosynthesis. The expression of these genes appeared independent in the embryo and endosperm and not correlated with ABA content in either tissue.

Conclusions

A high resolution QTL map for kernel desiccation and ABA content in embryo and endosperm showed several precise colocations between desiccation and ABA traits. Five new members of the maize NCED gene family and another maize ZEP gene were identified and mapped. Among all the identified candidates, aquaporins and members of the Responsive to ABA gene family appeared better candidates than NCEDs and ZEPs.