7196 research outputs found
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Strategies to Prevent and Elimination of Corynebacterium bovis from Animal Research Facility
No full textWith the development of innovative drug discovery, various of immunodeficiency mice or severe combined immunodeficiency mice was more widely used in each research institutions. The newly raised problem is that the barrier environment and animal populations of more animal research facilities be contaminated by Corynebacterium bovis (C.bovis). At present, the C.bovis has not been enrolled into China SPF Laboratory animal-Microbiologic standards, although this opportunistic pathogen has great threat to immunodeficiency animals. As rapid spread contamination and extremely difficult to eliminate of C.bovis, it is an extensive disaster to immunodeficiency animal facilities, and there was no appropriate prevention and elimination solutions in the past. In this paper, based on research progress and experience of two animal research facilities in past six years, a feasible strategy to prevent and eliminate C.bovis from barrier facilities was proposed
New Chemical Modalities and Strategic Thinking in Early Drug Discovery
No full textAbstract: The classical toolbox for drug discovery is continuously expanding beyond traditional small molecules. New chemical modalities including RNA therapeutics, protein degraders, cyclopeptides, antibody drug conjugates and gene therapy have matured with clinical successes and are now considered early in target appraisal. In this viewpoint, we highlight recent progress in the field
Activins as dual specificity TGF-β family molecules: SMAD-activation via activin- and BMP-type I receptors
No full textActivins belong to the transforming growth factor (TGF)-β family of multifunctional cytokines and signal via the activin receptors ALK4 or ALK7 to activate the SMAD2/3 pathway. In some cases, activins also signal via the bone morphogenetic protein (BMP) receptor ALK2 causing activation of the SMAD1/5/8 pathway. We here aimed to describe more carefully activation of the two main SMAD branches by activin A and activin B homodimers, and activin AB and activin AC heterodimers. We compared the activin-induced signaling kinetics of ALK4/7-SMAD2/3 and ALK2-SMAD1/5 in a multiple myeloma cell line. Signaling via ALK2 to SMAD1/5 varied more between ligands than signaling via ALK4/ALK7 to SMAD2/3. Interestingly, activin B and activin AB very potently activated SMAD1/5, resembling the activation commonly seen with BMPs. SMAD1/5 was also activated by activins in other cell types, indicating a general mechanism. The antagonist follistatin inhibited signaling by all the tested activins, whereas cerberus specifically antagonized activin B. Interestingly, ALK2-mediated activation of SMAD1/5 was blunted by mutations in the follistatin-binding region of activin A, whereas ALK4-mediated SMAD2/3 activation remained unchanged. Taken together, we propose that activins may be considered dual-specificity TGF-β family members and that this may affect the way activins are targeted clinically
Applying MAPPs assays to assess immunogenicity
No full textImmunogenicity against biotherapeutic proteins (BPs) and the outcome for the patient are difficult to predict. In vitro assays that can help to assess the immunogenic potential of BPs are not yet used routinely during drug development. MAPPs (MHC associated peptide proteomics) is one of the assays best characterized regarding its value for immunogenicity potential assessment. This review is focusing on recent studies that have employed human HLA class II-MAPPs assays to rank biotherapeutic candidates, investigate clinical immunogenicity and understand mechanistic root causes of immunogenicity. Advantages and challenges of the technology are discussed as well as the different areas of application
A Strategy to Assess the Cellular Activity of E3 Ligases against Neo-Substrates using Electrophilic Probes
No full textTargeted protein degradation promises to enable small molecule-mediated modulation of currently undrugged proteins. While the well-characterized E3 ligases CRBN and VHL have successfully promoted the degradation of many proteins of interest, there are approximately 600 additional E3 ligase family members that may offer improved activity, substrate selectivity, or tissue distribution; however, characterizing the ability of these many ligases to promote targeted protein degradation has proven challenging. Here, we report the development of a rapid method to evaluate the ability of recombinant E3 ligase components to support the degradation of neo-substrates. Bypassing the need for hit finding to identify specific E3 ligase binders, this approach makes use of simple chemistry for Covalent Functionalization Followed by E3 Electroporation into live cells (COFFEE). We demonstrate this method using covalent E3-target binder complexes of VHL-JQ1 and VHL-dasatinib and show the degradation of Brd4 and Lyn kinase, respectively. Applying COFFEE to SPSB2, a SOCS box and SPRY-domain E3 ligase not previously shown to degrade neo-substrates, we demonstrated the ability of this method to rapidly validate an uncharacterized ligase for degradation of neo-substrates
Toxicologic Pathology Forum Opinion Piece: Current Use of Non-blinded vs. Blinded Histopathologic Evaluation in Animal Toxicity Studies
No full textThe Society of Toxicologic Pathology (STP) explored current institutional practices for selecting between non-blinded vs. blinded histopathologic evaluation during Good Laboratory Practice (GLP)-compliant, regulatory-type animal toxicity studies using a multi-question survey and STP-wide discussion at the 2019 STP annual meeting. Survey responses were received from 107 individuals representing 87 institutions that collectively employ 589 toxicologic pathologists. Most responses came from industry (N = 46, mainly biopharmaceutical or contract research organizations) and consultants (N = 24). For GLP-compliant animal toxicity studies, histopathologic evaluation usually involves initial (primary) non-blinded analysis, with post hoc informal blinded re-examination at the study pathologist’s discretion to confirm subtle findings or establish thresholds. Initial blinded histopathologic evaluation sometimes is elected by study pathologists to test formal hypotheses and/or by sponsors to address non-pathologist expectations about histopathology data objectivity. Current practice is that a blinded histopathologic evaluation is documented only if a formal blinding (i.e., using slides with coded labels) is employed, using simple statements without detailed methodology in the Study Protocol (or an amendment) and/or pathology report. In general, blinding is an inappropriate strategy for the histopathologic evaluation during pathology peer reviews of GLP-compliant animal toxicity studies
An integrated assessment of the ADME properties of the CDK4/6 Inhibitor ribociclib utilizing preclinical in vitro, in vivo and human ADME data.
No full textRibociclib (LEE011, Kisqali ®) is a highly selective small molecule inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), which has been approved for the treatment of advanced or metastatic breast cancer. A human ADME study was conducted in healthy male volunteers following a single oral dose of 600 mg [14C]-ribociclib. Mass balance, blood and plasma radioactivity, and plasma ribociclib concentrations were measured. Metabolite profiling and identification was conducted in plasma, urine and feces. An assessment integrating the human ADME results with relevant in vitro and in vivo non-clinical data was conducted to provide an estimate of the relative contributions of various clearance pathways of the compound. Ribociclib is moderately to highly absorbed across species (approx. 59% in human), and is extensively metabolized in vivo, predominantly by oxidative pathways mediated by CYP3A4 (ultimately forming N-demethylated metabolite M4) and, to a lesser extent, by FMO3 (N-hydroxylated metabolite M13). It is extensively distributed in rats, based on QWBA data, and is eliminated rapidly from most tissues with the exception of melanin-containing structures. Ribociclib passed the placental barrier in rats and rabbits and into milk of lactating rats. In human 69.1% and 22.6% of the radiolabeled dose was excreted in feces and urine, respectively, with 17.3% and 6.75% of the 14C dose attributable to ribociclib, respectively. The remainder was attributed to numerous metabolites. Taking into account all available data, ribociclib is estimated to be eliminated by hepatic metabolism (approx. 84% of total), renal excretion (7%), intestinal excretion (8%) and biliary elimination (1%)
Stage-Specific Requirement for Eomes in Mature NK Cell Homeostasis and Cytotoxicity.
No full textNatural killer (NK) cells are cytotoxic innate lymphoid cells (ILCs) that mediate antiviral and antitumor responses and require the transcriptional regulator Eomesodermin (Eomes) for early development. However, the role of Eomes and its molecular program in mature NK cell biology is unclear. To address this, we develop a tamoxifen-inducible, type-1-ILC-specific (Ncr1-targeted) cre mouse and combine this with Eomes-floxed mice. Eomes deletion after normal NK cell ontogeny results in a rapid loss of NK cells (but not ILC1s), with a particularly profound effect on penultimately mature stage III NK cells. Mechanisms responsible for stage III reduction include increased apoptosis and impaired maturation from stage II precursors. Induced Eomes deletion also decreases NK cell cytotoxicity and abrogates in vivo rejection of major histocompatibility complex (MHC)-class-I-deficient cells. However, other NK cell functional responses, and stage IV NK cells, are largely preserved. These data indicate that mature NK cells have distinct Eomes-dependent and -independent stages