Proteomic study of calpain interacting proteins during skeletal muscle aging

Aging is associated with a progressive and involuntary loss of muscle mass also known as sarcopenia. This condition represents a major public health concern. Although sarcopenia is well documented, the molecular mechanisms of this condition still remain unclear. The calcium-dependent proteolytic system is composed of calcium-dependent cysteine proteases named calpains. Calpains are involved in a large number of physiological processes such as muscle growth and differentiation, and pathological conditions such as muscular dystrophies. The aim of this study was to determine the involvement of this proteolytic system in the phenotype associated with sarcopenia by identifying key proteins (substrates or regulators) interacting with calpains during muscle aging.     

Risk of second bone sarcoma following childhood cancer: role of radiation therapy treatment

Bone sarcoma as a second malignancy is rare but highly fatal. The present knowledge about radiation-absorbed organ dose–response is insufficient to predict the risks induced by radiation therapy techniques. The objective of the present study was to assess the treatment-induced risk for bone sarcoma following a childhood cancer and particularly the related risk of radiotherapy. Therefore, a retrospective cohort of 4,171 survivors of a solid childhood cancer treated between 1942 and 1986 in France and Britain has been followed prospectively. We collected detailed information on treatments received during childhood cancer. Additionally, an innovative methodology has been developed to evaluate the dose–response relationship between bone sarcoma and radiation dose throughout this cohort. The median follow-up was 26 years, and 39 patients had developed bone sarcoma. It was found that the overall incidence was 45-fold higher [standardized incidence ratio 44.8, 95 % confidence interval (CI) 31.0–59.8] than expected from the general population, and the absolute excess risk was 35.1 per 100,000 person-years (95 % CI 24.0–47.1). The risk of bone sarcoma increased slowly up to a cumulative radiation organ absorbed dose of 15 Gy [hazard ratio (HR) = 8.2, 95 % CI 1.6–42.9] and then strongly increased for higher radiation doses (HR for 30 Gy or more 117.9, 95 % CI 36.5–380.6), compared with patients not treated with radiotherapy. A linear model with an excess relative risk per Gy of 1.77 (95 % CI 0.6213–5.935) provided a close fit to the data. These findings have important therapeutic implications: Lowering the radiation dose to the bones should reduce the incidence of secondary bone sarcomas. Other therapeutic solutions should be preferred to radiotherapy in bone sarcoma-sensitive areas.     

From Scourge to Cure: Tumour-Selective Viral Pathogenesis as a New Strategy against Cancer

Tumour mutations corrupt cellular pathways, and accumulate to disrupt, dysregulate, and ultimately avoid mechanisms of cellular control. Yet the very changes that tumour cells undergo to secure their own growth success also render them susceptible to viral infection. Enhanced availability of surface receptors, disruption of antiviral sensing, elevated metabolic activity, disengagement of cell cycle controls, hyperactivation of mitogenic pathways, and apoptotic avoidance all render the malignant cell environment highly supportive to viral replication. The therapeutic use of oncolytic viruses (OVs) with a natural tropism for infecting and subsequently lysing tumour cells is a rapidly progressing area of cancer research. While many OVs exhibit an inherent degree of tropism for transformed cells, this can be further promoted through pharmacological interventions and/or the introduction of viral mutations that generate recombinant oncolytic viruses adapted to successfully replicate only in a malignant cellular environment. Such adaptations that augment OV tumour selectivity are already improving the therapeutic outlook for cancer, and there remains tremendous untapped potential for further innovation.     

Augmentative on-farm delivery methods for the parasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae) to control the millet head miner Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) in Burkina Faso and Niger

Augmentative on-farm delivery methods for the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) to control the millet head miner (MHM) Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) were investigated in Burkina Faso from 2011 to 2012 and in Niger in 2012. Our findings indicate that 7 cm × 10 cm jute bags containing 50 g of millet grains, 30 g of millet flour, 25 Corcyra cephalonica larvae and two mated H. hebetor females are the most effective option for on-farm delivery of the parasitoid. The parasitoid progeny started emerging from the bags eight days after confinement and 57–71 parasitoid adults emerged from each bag. Using the methods we developed, over 90 % parasitism of MHM larvae was achieved in millet farms. The implications of these findings for a large extension of MHM biocontrol program are discussed.     

Cortactin Is a Functional Target of E-cadherin-activated Src Family Kinases in MCF7 Epithelial Monolayers

Src family kinases (SFKs) signal in response to E-cadherin to support cadherin adhesion and the integrity of cell-cell contacts (McLachlan, R. W., Kraemer, A., Helwani, F. M., Kovacs, E. M., and Yap, A. S. (2007) Mol. Biol. Cell 18, 3214–3223). We now identify the actin-regulatory protein, cortactin, as a target of E-cadherin-activated SFK signaling. Tyr-phosphorylated cortactin was found at cell-cell contacts in established epithelial monolayers, and cortactin became acutely tyrosine-phosphorylated when E-cadherin adhesion was engaged. In all circumstances, cortactin tyrosine phosphorylation was blocked by inhibiting SFK signaling. Importantly, Tyr-phosphorylated cortactin was necessary to preserve the integrity of cadherin contacts and the perijunctional actin cytoskeleton. Moreover, expression of a phosphomimetic cortactin mutant could prevent SFK blockade from disrupting cadherin organization, thereby placing cortactin functionally downstream of SFK signaling at cadherin adhesions. We conclude that SFK and cortactin constitute an important signaling pathway that functionally links E-cadherin adhesion and the actin cytoskeleton.Functional cooperation between cadherin adhesion receptors and the actin cytoskeleton is commonly believed to play a key role in the morphogenesis of cell-cell interactions (1, 2). This functional interplay, and the biochemical mechanisms that underpin it, are much more complex than previously realized. Increasingly it is apparent that a range of distinct actin regulators can be recruited to cadherin adhesions depending on the biological context of cell-cell interactions (2). It is likely that the choice of actin regulator(s) recruited determines the dynamics and organization of the actin cytoskeleton at those contacts, with morphogenetic implications for the formation, modeling, and turnover of cell-cell interactions. Identifying the actin regulators that influence cell-cell interactions and how they cooperate with adhesion receptors are important open issues.Adhesion-activated cell signaling provides a useful paradigm to analyze how classical cadherins regulate the actin cytoskeleton (2, 3). Over the past several years, a range of signal transduction pathways have been identified that are stimulated upon productive engagement of cadherins, such as E-, C-, and N-cadherin (reviewed in Ref. 3). Among these signals are Rho family GTPases, lipid kinases, and protein-tyrosine kinases. Of the latter, we recently identified Src family kinase (SFK)⁵ activity as a component of E-cadherin signaling (4). SFK was stimulated in an E-cadherin-dependent fashion when cells assembled contacts with one another. Indeed, binding to recombinant cadherin ligands was sufficient to activate SFK, implying that the cadherin itself can serve as a receptor to transduce an adhesive signal to SFK. Furthermore, inhibiting SFK signaling perturbed cadherin adhesion and the integrity of cell-cell contacts. This suggested a model where adhesive ligation of E-cadherin stimulated an SFK signaling cascade to ultimately support cell-cell interactions. An important challenge now is to identify targets of cadherin-activated SFK signaling that contribute to cadherin biology.In this work, we tested whether the actin-binding protein, cortactin, might be just such a target. A multidomain scaffolding protein, cortactin regulates the actin cytoskeleton by interacting with a range of other actin-regulatory proteins (5, 6). It is best understood to participate in actin filament assembly (6) by promoting Arp2/3-mediated actin nucleation and also by stabilizing nascent Arp2/3-generated actin filament branches (7). Cortactin exerts many of these effects through direct interactions with actin filaments and Arp2/3 (8) as well as indirectly by associating with proteins such as N-WASP and WIP, which can themselves activate Arp2/3. Consistent with this, cortactin is often found at sites in the cortex where Arp2/3 drives membrane protrusion, such as lamellipodia and invadopodia (9).Cortactin is also found at cadherin-based cell-cell contacts where a biochemical complex with E-cadherin or N-cadherin has been detected by co-immunoprecipitation analysis (10–12). Moreover, ligation of the cadherin with recombinant ligands could induce formation of a complex with cortactin and also recruited cortactin to the cortex at the sites of adhesion (10, 12). Cortactin is found with Arp2/3 at newly forming E-cadherin adhesive contacts, and disruption of cortactin by RNAi or dominant-negative mutants perturbs efficient assembly of cadherin-based contacts (10). At N-cadherin adhesions, cortactin promotes adhesive strengthening and its surface expression (12). Overall, these reports identified a role for cortactin in modulating cadherin biology, likely through regulation of the cadherin-based actin cytoskeleton.Of note, cortactin was first identified as a substrate for v-Src (13) and as a target of fibroblast growth factor-stimulated SFK signaling (14). Tyrosine phosphorylation of cortactin is implicated in cellular events that are accompanied by extensive remodeling of the actin cytoskeleton, such as cell migration and invasion (6, 15, 16). Building on our earlier experience in epithelial cells (4, 10), we now report that E-cadherin ligation induces the tyrosine phosphorylation of cortactin through an SFK-dependent signaling pathway. Furthermore, we demonstrate that phosphorylation at the key Tyr-421, Tyr-466, and Tyr-482 residues is necessary to maintain the integrity of established cell-cell contacts and their perijunctional actin cytoskeleton.     

Les complications urinaires des traumatismes du bassin: aspects anatomocliniques et thérapeutiques au CHU de Conakry, Guinée

Objective

To stick out the anatomoclinic aspects and to evaluate the therapeutic results of a series of some pelvic trauma complications is followed at the Urology-Andrology ward in the teaching hospital of Conakry.

Material and method

It’s about a retrospective examined joining together 52 cases of some pelvic trauma complications in a period of five years.

Results

The pelvic trauma complications were representing 3% of whole the hospitalisations during the period of study. The mean age of our patients was 33 years with extremes of 10 and 63 years. The traumas were due to accidents on the public road in 54.9% of cases. In terms of clinics, the symptomatology was essentially constituted by the acute retention of urines with 80.7% of cases and the hemorrhage (hematury and uretrorragy). The main trauma was a back urethral lesion with 82.7% of cases. All the patients profited a surgical treatment. The therapeutics has been judged after an average relapse of 52 months in terms of urinary and sexual complications. Thus, in terms of urinary complications results have been judged good in 59.6% of cases, less in 17.3% and bad in 23.7% of cases. In terms of sexual, we remarked 53.8% of good result, 25% of medium results and 21.2% (N = 11) of bad results.

Conclusion

Management of urinary complication after pelvic trauma is controversy. Thus, we insist on more necessary collaboration between urologist and orthopedist because the stabilisation of the pelvic trauma is very interesting to the management.     

Monitoring mitochondrial electron fluxes using NAD(P)H-flavoprotein fluorometry reveals complex action of isoflurane on cardiomyocytes

Mitochondrial bioenergetic studies mostly rely on isolated mitochondria thus excluding the regulatory role of other cellular compartments important for the overall mitochondrial function. In intact cardiomyocytes, we followed the dynamics of electron fluxes along specific sites of the electron transport chain (ETC) by simultaneous detection of NAD(P)H and flavoprotein (FP) fluorescence intensities using a laser-scanning confocal microscope. This method was used to delineate the effects of isoflurane, a volatile anesthetic and cardioprotective agent, on the ETC. Comparison to the effects of well-characterized ETC inhibitors and uncoupling agent revealed two distinct effects of isoflurane: uncoupling-induced mitochondrial depolarization and inhibition of ETC at the level of complex I. In correlation, oxygen consumption measurements in cardiomyocytes confirmed a dose-dependent, dual effect of isoflurane, and in isolated mitochondria an obstruction of the ETC primarily at the level of complex I. These effects are likely responsible for the reported mild stimulation of mitochondrial reactive oxygen species (ROS) production required for the cardioprotective effects of isoflurane. In conclusion, isoflurane exhibits complex effects on the ETC in intact cardiomyocytes, altering its electron fluxes, and thereby enhancing ROS production. The NAD(P)H-FP fluorometry is a useful method for exploring the effect of drugs on mitochondria and identifying their specific sites of action within the ETC of intact cardiomyocytes.     

Identification by PCR of Non-typhoidal Salmonella enterica Serovars Associated with Invasive Infections among Febrile Patients in Mali

Background

In sub-Saharan Africa, non-typhoidal Salmonella (NTS) are emerging as a prominent cause of invasive disease (bacteremia and focal infections such as meningitis) in infants and young children. Importantly, including data from Mali, three serovars, Salmonella enterica serovar Typhimurium, Salmonella Enteritidis and Salmonella Dublin, account for the majority of non-typhoidal Salmonella isolated from these patients.

Methods

We have extended a previously developed series of polymerase chain reactions (PCRs) based on O serogrouping and H typing to identify Salmonella Typhimurium and variants (mostly I 4,[5],12:i:-), Salmonella Enteritidis and Salmonella Dublin. We also designed primers to detect Salmonella Stanleyville, a serovar found in West Africa. Another PCR was used to differentiate diphasic Salmonella Typhimurium and monophasic Salmonella Typhimurium from other O serogroup B, H:i serovars. We used these PCRs to blind-test 327 Salmonella serogroup B and D isolates that were obtained from the blood cultures of febrile patients in Bamako, Mali.

Principal Findings

We have shown that when used in conjunction with our previously described O-serogrouping PCR, our PCRs are 100% sensitive and specific in identifying Salmonella Typhimurium and variants, Salmonella Enteritidis, Salmonella Dublin and Salmonella Stanleyville. When we attempted to differentiate 171 Salmonella Typhimurium (I 4,[ 5],12:i:1,2) strains from 52 monophasic Salmonella Typhimurium (I 4,[5],12:i:-) strains, we were able to correctly identify 170 of the Salmonella Typhimurium and 51 of the Salmonella I 4,[5],12:i:- strains.

Conclusion

We have described a simple yet effective PCR method to support surveillance of the incidence of invasive disease caused by NTS in developing countries.