Synthesis and biological evaluation of new active For‐Met‐Leu‐Phe‐OMe analogues containing para‐substituted Phe residues

In the present study, we report synthesis and biological evaluation of the N‐Boc‐protected tripeptides 4a–l and N‐For protected tripeptides 5a–l as new For‐Met‐Leu‐Phe‐OMe (fMLF‐OMe) analogues. All the new ligands are characterized by the C‐terminal Phe residue variously substituted at position 4 of the aromatic ring. The agonism of 5a–l and the antagonism of 4a–l (chemotaxis, superoxide anion production, lysozyme release as well as receptor binding affinity) have been examined on human neutrophils. No synthesized compounds has higher activity than the standard fMLF‐OMe tripeptide to stimulate chemotaxis, although compounds 5a and 5c with ‐CH₃ and ‐C(CH₃)₃, respectively, in position 4 on the aromatic ring, are better than the standard tripeptide to stimulate the production of superoxide anion, in higher concentration. Compounds 4f and 4i , containing ‐F and ‐I in position 4, respectively, on the aromatic ring of phenylalanine, exhibit significant chemotactic antagonism. The influence of the different substitution at the position 4 on the aromatic ring of phenylalanine is discussed. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Human cytomegalovirus end-organ disease is associated with high or low systemic viral load in preemptively treated solid-organ transplant recipients

Human cytomegalovirus (HCMV) end-organ disease in solid-organ transplant recipients (SOTR) may be associated with either high or low HCMV load in blood. In transplantation Centers where the preemptive therapy approach is adopted, antiviral therapy of systemic HCMV infections is initiated upon reaching pre-determined cut-off levels of viral DNA in blood, whereas no guidelines are provided for local end-organ infection/disease. In the latter case, clinicians often start antiviral treatment without defining the etiology of local symptoms. Here, we describe 14 cases of SOTR, in which a documented HCMV end-organ disease was observed. Nine patients had a systemic viral load lower than the cut-off for preemptive therapy and were treated based on viral load of local HCMV disease. The remaining five patients had a systemic viral load greater than the preemptive therapy cut-off and were efficiently treated for both the systemic and the local HCMV disease. Thus, HCMV infection in the post-transplant period must be monitored virologically both in blood and locally. End-organ disease in preemptively treated patients, seems to be associated with lack of development (primary HCMV infection) or reconstitution (reactivated infection) of HCMV-specific CD4+ and CD8+ T-cell immunity or with its functional impairment.     

Proteomic analysis reveals new cardiac-specific dystrophin-associated proteins

Mutations affecting the expression of dystrophin result in progressive loss of skeletal muscle function and cardiomyopathy leading to early mortality. Interestingly, clinical studies revealed no correlation in disease severity or age of onset between cardiac and skeletal muscles, suggesting that dystrophin may play overlapping yet different roles in these two striated muscles. Since dystrophin serves as a structural and signaling scaffold, functional differences likely arise from tissue-specific protein interactions. To test this, we optimized a proteomics-based approach to purify, identify and compare the interactome of dystrophin between cardiac and skeletal muscles from as little as 50 mg of starting material. We found selective tissue-specific differences in the protein associations of cardiac and skeletal muscle full length dystrophin to syntrophins and dystrobrevins that couple dystrophin to signaling pathways. Importantly, we identified novel cardiac-specific interactions of dystrophin with proteins known to regulate cardiac contraction and to be involved in cardiac disease. Our approach overcomes a major challenge in the muscular dystrophy field of rapidly and consistently identifying bona fide dystrophin-interacting proteins in tissues. In addition, our findings support the existence of cardiac-specific functions of dystrophin and may guide studies into early triggers of cardiac disease in Duchenne and Becker muscular dystrophies.     

Internal soft-tissue anatomy of cambrian 'orsten' arthropods as revealed by synchrotron x-ray tomographic microscopy

The world-famous ‘Orsten’ Konservat-Lagerstätte has yielded detailed information about Cambrian arthropods and their morphology. Internal organs or soft tissues have, however, rarely been reported, an obvious palaeobiological drawback. In this study, we employed synchrotron radiation X-ray tomographic microscopy (SRXTM) to study microscopic ‘Orsten’ arthropods from the Cambrian of Sweden: Skara minuta and two phosphatocopine species, Hesslandona sp. and Hesslandona trituberculata. This exceptionally high-resolution technique reveals internal organs or soft tissues that allow detailed comparison with equivalent structures in extant crustaceans and functional inferences to be made. The S. minuta specimen shows the digestive system and muscles that extend to the extremities. The slanting anterior portion of the head and anterior position of the mouth with a straight oesophagus suggest a primarily brushing and scraping way of feeding. The prominent head appendage muscles indicate muscle strength and good capacity for food manipulation. In the phosphatocopines the bulbous labrum is one of the most prominent morphological structures of the body. All specimens analysed reveal pairs of muscle bundles within the labrum. Based on comparisons with extant crustacean relatives, these muscles would fulfil the function of moving the labrum up and down in order to open the buccal cavity. The results of this pilot study demonstrate that there is still much to be learned about the ‘Orsten’ taxa.     

The neural bases of social intention understanding: the role of interaction goals

Decoding others' intentions is a crucial aspect of social cognition. Neuroimaging studies suggest that inferring immediate goals engages the neural system for action understanding (i.e. mirror system), while the decoding of long-term intentions requires the system subserving the attribution of mental states (i.e. mentalizing). A controversial issue, stimulated by recent inconsistent results, concerns whether the two systems are concurrently vs. exclusively involved in intention understanding. This issue is particularly relevant in the case of social interactions, whose processing has been mostly, but not uncontroversially, associated with the mentalizing system. We tested the alternative hypothesis that the relative contribution of the two systems in intention understanding may also depend on the shared goal of interacting agents. To this purpose, 27 participants observed social interactions differing in their cooperative vs. affective shared goal during functional-Magnetic-Resonance-Imaging. The processing of both types of interactions activated the right temporo-parietal junction involved in mentalizing on action goals. Additionally, whole-brain and regions-of-interest analyses showed that the action understanding system (inferior prefrontal-parietal cortex) was more strongly activated by cooperative interactions, while the mentalizing-proper system (medial prefrontal cortex) was more strongly engaged by affective interactions. These differences were modulated by individual differences in empathizing. Both systems can thus be involved in understanding social intentions, with a relative weighting depending on the specific shared goal of the interaction.     

The insulin receptor substrate 1 (IRS1) in intestinal epithelial differentiation and in colorectal cancer

Colorectal cancer (CRC) is associated with lifestyle factors that affect insulin/IGF signaling, of which the insulin receptor substrate 1 (IRS1) is a key transducer. We investigated expression, localization and pathologic correlations of IRS1 in cancer-uninvolved colonic epithelium, primary CRCs with paired liver metastases and in vitro polarizing Caco2 and HT29 cells. IRS1 mRNA and protein resulted higher, relative to paired mucosa, in adenomas of familial adenomatous polyposis patients and in CRCs that overexpressed c-MYC, ß-catenin, InsRß, and IGF1R. Analysis of IRS1 immunostaining in 24 cases of primary CRC with paired colonic epithelium and hepatic metastasis showed that staining intensity was significantly higher in metastases relative to both primary CRC (P<0.01) and colonic epithelium (P<0.01). Primary and metastatic CRCs, compared to colonic epithelium, contained significantly higher numbers of IRS1-positive cells (P = 0.013 and P = 0.014, respectively). Pathologic correlations in 163 primary CRCs revealed that diffuse IRS1 staining was associated with tumors combining differentiated phenotype and aggressive markers (high Ki67, p53, and ß-catenin). In Caco 2 IRS1 and InsR were maximally expressed after polarization, while IGF1R was highest in pre-polarized cells. No nuclear IRS1 was detected, while, with polarization, phosphorylated IRS1 (pIRS1) shifted from the lateral to the apical plasma membrane and was expressed in surface cells only. In HT29, that carry mutations constitutively activating survival signaling, IRS1 and IGF1R decreased with polarization, while pIRS1 localized in nuclear spots throughout the course. Overall, these data provide evidence that IRS1 is modulated according to CRC differentiation, and support a role of IRS1 in CRC progression and liver metastatization.     

Pharmacological targeting of mitochondrial complex I deficiency: the cellular level and beyond

Complex I (CI) represents a major entry point of electrons in the mitochondrial electron transport chain (ETC). It consists of 45 different subunits, encoded by the mitochondrial (mtDNA) and nuclear DNA (nDNA). In humans, mutations in nDNA-encoded subunits cause severe neurodegenerative disorders like Leigh Syndrome with onset in early childhood. The pathophysiological mechanism of these disorders is still poorly understood. Here we summarize the current knowledge concerning the consequences of nDNA-encoded CI mutations in patient-derived cells, present mouse models for human CI deficiency, and discuss potential treatment strategies for CI deficiency.     

Generation of skeletal muscle cells from embryonic and induced pluripotent stem cells as an in vitro model and for therapy of muscular dystrophies

Muscular dystrophies (MDs) are a heterogeneous group of inherited disorders characterized by progressive muscle wasting and weakness likely associated with exhaustion of muscle regeneration potential. At present, no cures or efficacious treatments are available for these diseases, but cell transplantation could be a potential therapeutic strategy. Transplantation of myoblasts using satellite cells or other myogenic cell populations has been attempted to promote muscle regeneration, based on the hypothesis that the donor cells repopulate the muscle and contribute to its regeneration. Embryonic stem cells (ESCs) and more recently induced pluripotent stem cells (iPSCs) could generate an unlimited source of differentiated cell types, including myogenic cells. Here we review the literature regarding the generation of myogenic cells considering the main techniques employed to date to elicit efficient differentiation of human and murine ESCs or iPSCs into skeletal muscle. We also critically analyse the possibility of using these cellular populations as an alternative source of myogenic cells for cell therapy of MDs.