Random mutagenesis of PDZOmi domain and selection of mutants that specifically bind the Myc proto-oncogene and induce apoptosis

peer reviewedOmi is a mammalian serine protease that is localised in the mitochondria and released to the cytoplasm in response to apoptotic stimuli. Omi induces cell death in a caspase-dependent manner by interacting with the Xchromosome linked inhibitor of apoptosis protein, as well as in a caspase-independent way that relies on its proteolytic activity. Omi is synthesized as a precursor polypeptide and is processed to an active serene protease with a unique PDZ domain. PDZ domains recognise the extreme carboxyl terminus of target proteins. Internal peptides that are able to fold into a b-finger are also reported to bind some PDZ domains. Using a modified yeast two-hybrid system, PDZOmi mutants were isolated by their ability to bind the carboxyl terminus of human Myc oncoprotein in yeast as well as in mammalian cells. One such PDZm domain (PDZ-M1), when transfected into mammalian cells, was able to bind to endogenous Myc protein and induce cell death. PDZ-M1-induced apoptosis was entirely dependent on the presence of Myc protein and was not observed when c-myc null fibroblasts were used. Our studies indicate that the PDZ domain of Omi can provide a prototype that could easily be exploited to target specifically and inactivate oncogenes by binding to their unique carboxyl terminus

Low-Molecular-Weight Protein Tyrosine Phosphatases of Bacillus subtilis

In gram-negative organisms, enzymes belonging to the low-molecular-weight protein tyrosine phosphatase (LMPTP) family are involved in the regulation of important physiological functions, including stress resistance and synthesis of the polysaccharide capsule. LMPTPs have been identified also in gram-positive bacteria, but their functions in these organisms are presently unknown. We cloned two putative LMPTPs from Bacillus subtilis, YfkJ and YwlE, which are highly similar to each other in primary structure as well as to LMPTPs from gram-negative bacteria. When purified from overexpressing Escherichia coli strains, both enzymes were able to dephosphorylate p-nitrophenyl-phosphate and phosphotyrosine-containing substrates in vitro but showed significant differences in kinetic parameters and sensitivity to inhibitors. Transcriptional analyses showed that yfkJ was transcribed at a low level throughout the growth cycle and underwent a σB-dependent transcriptional upregulation in response to ethanol stress. The transcription of ywlE was growth dependent but stress insensitive. Genomic deletion of each phosphatase-encoding gene led to a phenotype of reduced bacterial resistance to ethanol stress, which was more marked in the ywlE deletion strain. Our study suggests that YfkJ and YwlE play roles in B. subtilis stress resistance

Oral Antiplatelet Therapy for Secondary Prevention of Non-Cardioembolic Ischemic Cerebrovascular Events

Stroke is the leading cause of disability and mortality worldwide. After an acute cerebrovascular ischemia, recurrent vascular events, including recurrent stroke or transient ischemic accidents (TIA), occur in around 20% of cases within the first 3 months. In order to minimize this percentage, antiplatelet therapy may play a key role in the management of non-cardioembolic cerebrovascular events. This review will focus on the current evidence of antiplatelet therapies most commonly discussed in practice guidelines and used in clinical practice for the treatment of stroke/TIA complications. The antiplatelet therapies most commonly used and discussed are as follows: aspirin, clopidogrel, and ticagrelor

Synthesis of ticagrelor analogues belonging to 1,2,3-triazolo[4,5-d]pyrimidines and study of their antiplatelet and antibacterial activity.

peer reviewedBased on the recent observation that the antiplatelet agent ticagrelor and one of its metabolite exert bactericidal activity against gram-positive bacteria, a series of 1,2,3-triazolo[4,5-d]pyrimidines structurally related to ticagrelor were synthesized and examined as putative antiplatelet and antibacterial agents. The aim was to assess the possibility of dissociating the two biological properties and to find novel 1,2,3-triazolo[4,5-d]pyrimidines expressing antiplatelet activity and devoid of in vitro antibacterial activity. The new compounds synthesized were known metabolites of ticagrelor as well as structurally simplified analogues. Some of them were found to express antiplatelet activity and to lose the antibacterial activity, supporting the view that the two activities were not necessarily linked

M48U1 and Tenofovir combination synergistically inhibits HIV infection in activated PBMCs and human cervicovaginal histocultures

Microbicides are considered a promising strategy for preventing human immunodeficiency virus (HIV-1) transmission and disease. In this report, we first analyzed the antiviral activity of the miniCD4 M48U1 peptide formulated in hydroxyethylcellulose (HEC) hydrogel in activated peripheral blood mononuclear cells (PBMCs) infected with R5-and X4-Tropic HIV-1 strains. The results demonstrate that M48U1 prevented infection by several HIV-1 strains including laboratory strains, and HIV-1 subtype B and C strains isolated from the activated PBMCs of patients. M48U1 also inhibited infection by two HIV-1 transmitted/founder infectious molecular clones (pREJO.c/2864 and pTHRO.c/2626). In addition, M48U1 was administered in association with tenofovir, and these two antiretroviral drugs synergistically inhibited HIV-1 infection. In the next series of experiments, we tested M48U1 alone or in combination with tenofovir in HEC hydrogel with an organ-like structure mimicking human cervicovaginal tissue. We demonstrated a strong antiviral effect in absence of significant tissue toxicity. Together, these results indicate that co-Treatment with M48U1 plus tenofovir is an effective antiviral strategy that may be used as a new topical microbicide to prevent HIV-1 transmission

SI113, a Specific Inhibitor of the Sgk1 Kinase Activity that Counteracts Cancer Cell Proliferation

Background/Aims: Published observations on serum and glucocorticoid regulated kinase 1 (Sgk1) knockout murine models and Sgk1-specific RNA silencing in the RKO human colon carcinoma cell line point to this kinase as a central player in colon carcinogenesis and in resistance to taxanes. Methods: By in vitro kinase activity inhibition assays, cell cycle and viability analysis in human cancer model systems, we describe the biologic effects of a recently identified kinase inhibitor, SI113, characterized by a substituted pyrazolo[3,4-d]pyrimidine scaffold, that shows specificity for Sgk1. Results: SI113 was able to inhibit in vitro cell growth in cancer cells derived from tumors with different origins. In RKO cells, this kinase inhibitor blocked insulin-dependent phosphorylation of the Sgk1 substrate Mdm2, the main regulator of p53 protein stability, and induced necrosis and apoptosis when used as a single agent. Finally, SI113 potentiated the effects of paclitaxel on cell viability. Conclusion: Since SI113 appears to be effective in inducing cell death in RKO cells, potentiating paclitaxel sensitivity, we believe that this new molecule could be efficiently employed, alone or in combination with paclitaxel, in colon cancer chemotherapy

Primary mitochondrial myopathy: Clinical features and outcome measures in 118 cases from Italy

Objective: To determine whether a set of functional tests, clinical scales, patient-reported questionnaires, and specific biomarkers can be considered reliable outcome measures in patients with primary mitochondrial myopathy (PMM), we analyzed a cohort of Italian patients. Methods: Baseline data were collected from 118 patients with PMM, followed by centers of the Italian network for mitochondrial diseases. We used the 6-Minute Walk Test (6MWT), Timed Up-and-Go Test (x3) (3TUG), Five-Times Sit-To-Stand Test (5XSST), Timed Water Swallow Test (TWST), and Test of Masticating and Swallowing Solids (TOMASS) as functional outcome measures; the Fatigue Severity Scale and West Haven-Yale Multidimensional Pain Inventory as patient-reported outcome measures; and FGF21, GDF15, lactate, and creatine kinase (CK) as biomarkers. Results: A total of 118 PMM cases were included. Functional outcome measures (6MWT, 3TUG, 5XSST, TWST, and TOMASS) and biomarkers significantly differed from healthy reference values and controls. Moreover, functional measures correlated with patients' perceived fatigue and pain severity. Patients with either mitochondrial or nuclear DNA point mutations performed worse in functional measures than patients harboring single deletion, even if the latter had an earlier age at onset but similar disease duration. Both the biomarkers FGF21 and GDF15 were significantly higher in the patients compared with a matched control population; however, there was no relation with severity of disease. Conclusions: We characterized a large cohort of PMM by evaluating baseline mitochondrial biomarkers and functional scales that represent potential outcome measures to monitor the efficacy of treatment in clinical trials; these outcome measures will be further reinvestigated longitudinally to define the natural history of PMM

Chitotriosidase expression in monocyte-derived dendritic cells

Chitotriosidase (CHIT1) belongs to 18 glycosyl-hydrolase family, an ancient gene family that is widely expressed from prokaryotes to eukaryotes [1]. CHIT1 is a very critical enzyme to regulate the susceptibility to infection of organisms containing chitin as structural components. Conversely, during the development of acute/chronic inflammatory disorders, the enzymatic activity of CHIT1 increases significantly. The CHIT1 is expressed in activated macrophages as well in different lines monocyte-derived such as Kupffer cells and osteoclasts [2]. So far, it is unknown whether CHIT1 is expressed in other cells involved in the immune response such as monocyte-derived DCs. In this study we have investigated whether CHIT1 is produced in monocyte-derived DCs (moDCs) and the differential expression of CHIT1 during the different stage of moDCs differentiation. The presence of CHIT1 were examined by real time RT-PCR, Western Blot and Confocal Immunofluorescence, in Immature Dendritic cells (iDCs), generated from human monocytes by stimulation with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) and in mature Dendritic cells (mDCs), obtained by using lipopolysaccharide (LPS) and interferon-gamma (IFN-g). We observed that CHIT1 was expressed during the DCs differentiation and maturation process in time dependent manner. The maturation of DCs showed a significantly increased expression of CHIT1 mRNA and protein. Furthermore, the CHIT1 was evenly distributed in cytoplasm both in iDCs and in mDCs. The enzymatic activity confirmed that CHIT1 could play a role in moDCs function. Taken together, our data confirm the crucial role of CHIT1 in primary immune responses and indicate that could be correlated with the immunogenicity of DCs

Expression and localization of CHI3L1 in monocyte derived dendritic cells

Chitinase-3-like-1 protein (CHI3L1) also called YKL-40, is a 40 kDa mammalian glycoprotein which is a heparin, chitin and collagen binding member of the mammalian chitinase-like proteins. Biological activities of CHI3L1 embrace regulation of cell proliferation, adhesion, angiogenesis, migration and activation. CHI3L1 is produced by variety of cells, including neutrophils, monocytes/macrophages, osteoclasts and Kupffer cells [1]. CHI3L1 secretion is induced by interferon (INF)-g and interleukin (IL)-6 and is an acute phase reactant associated with disease severity and mortality in a variety of infectious [2]. In this study, we have examined the expression and localization of CHI3L1 during the differentiation and maturation of monocyte derived dendritic cells by real time RT-PCR, Western Blot, Confocal Immunofluorescence, and Immunocytochemical assays. Potential nuclear localization signal (NLS) was determinated using the open source software cNLS Mapper and Chimera. Peripheral blood monocytes were differentiated toward immature DCs (iDC) and mature DCs (mDCs) through a combination of factors and cytokines. Our result showed, for the first time, that CHI3L1 is expressed during the process of differentiation and maturation of DCs in time dependent manner. Furthermore, CHI3L1 is evenly distributed in cytoplasm and in the nucleus of both the iDCs and mDCs. In conclusion, the discovery of CHI3L1 expression in DCs has opened new dilemma for designing DC-based cancer immunotherapeutic. In fact, on the light of these results one can’t exclude that as well as activated Tumor-associated macrophages (TAMs) also DCs infiltration could to be a significant unfavorable prognostic factor for cancer patients