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Slough is a well‐known feature of non‐healing wounds. This pilot study aims to determine the proteomic and microbiologic components of slough as well as interrogate the associations between wound slough components and wound healing. Ten subjects with slow‐to‐heal wounds and visible slough were enrolled. Aetiologies included venous stasis ulcers, post‐surgical site infections and pressure ulcers. Patient co‐morbidities and wound healing outcome at 3‐months post‐sample collection was recorded. Debrided slough was analysed microscopically, through untargeted proteomics, and high‐throughput bacterial 16S‐ribosomal gene sequencing. Microscopic imaging revealed wound slough to be amorphous in structure and highly variable. 16S‐profiling found slough microbial communities to associate with wound aetiology and location on the body. Across all subjects, slough largely consisted of proteins involved in skin structure and formation, blood‐clot formation and immune processes. To predict variables associated with wound healing, protein, microbial and clinical datasets were integrated into a supervised discriminant analysis. This analysis revealed that healing wounds were enriched for proteins involved in skin barrier development and negative regulation of immune responses. While wounds that deteriorated over time started off with a higher baseline Bates‐Jensen Wound Assessment Score and were enriched for anaerobic bacterial taxa and chronic inflammatory proteins. To our knowledge, this is the first study to integrate clinical, microbiome, and proteomic data to systematically characterise wound slough and integrate it into a single assessment to predict wound healing outcome. Collectively, our findings underscore how slough components can help identify wounds at risk of continued impaired healing and serves as an underutilised biomarker. [ABSTRACT FROM AUTHOR]

More than 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publicly available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment, called the Public Repository of Xenografts (PRoXe). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional, and proteomic biomarkers in both treatment-naive and relapsed/refractory disease.

Background Increased microbial translocation (MT) into the systemic circulation is associated with liver disease progression. Microbial translocation has yet to be completely defined in chronic hepatitis B virus (HBV) and chronic hepatitis delta virus (HDV). Methods Our aim was to characterize MT and associated immune response in chronic HBV and HDV at various stages of disease. Serum from 53 HBV, 43 HDV, and 36 healthy control (HC) subjects was obtained. Subjects were categorized by aspartate aminotransferase-to-platelet ratio index into mild (<0.5), moderate, and severe (>1.0) disease. Cytokines, microbial products, and microbial deoxyribonucleic acid (DNA) levels were assessed in a single treatment-naive time point for each patient. Next-generation sequencing identified bacterial species present within patient sera. Results The HBV and HDV subjects display higher serum concentrations of Gram-negative (G−) bacterial lipopolysaccharide and fungal beta-glucan compared with HC (all P <.01). Gram-positive (G+) bacterial peptidoglycan is higher in HBV compared to HDV and HC (both P <.0001). Within both disease cohorts, peptidoglycan correlates with interleukin (IL)-1b, IL-8, IL-12p70, and IL-13 (all Spearman's rho >0.45; P <.05). Next-generation sequencing from 7 subjects with detectable serum bacterial DNA revealed changes in abundance of bacterial taxa and a higher proportion of Gram-positive genera in severe disease. Greater G+/G− taxa ratio is associated with higher cytokine levels and disease markers. Conclusions The HBV and HDV patients display increased translocation of bacterial and fungal products into serum. An increased proportion of Gram-positive genera is associated with disease progression. Correlations of peptidoglycan with antimicrobial cytokines suggest that particular microbial classes may contribute to systemic inflammation and possibly disease progression. [ABSTRACT FROM AUTHOR]

Mixed lineage leukemia 1 (MLL1) is a histone H3 lysine 4 (H3K4) methyltransferase, and targeting the MLL1 enzymatic activity has been proposed as a novel therapeutic strategy for the treatment of acute leukemia harboring MLL1 fusion proteins. The MLL1/WDR5 protein-protein interaction is essential for MLL1 enzymatic activity. In the present study, we designed a large number of peptidomimetics to target the MLL1/WDR5 interaction based upon -CO-ARA-NH-, the minimum binding motif derived from MLL1. Our study led to the design of high-affinity peptidomimetics, which bind to WDR5 with Ki < 1 nM and function as potent antagonists of MLL1 activity in a fully reconstituted in vitro H3K4 methyltransferase assay. Determination of co-crystal structures of two potent peptidomimetics in complex with WDR5 establishes their structural basis for high-affinity binding to WDR5. Evaluation of one such peptidomimetic, MM-102, in bone marrow cells transduced with MLL1-AF9 fusion construct shows that the compound effectively decreases the expression of HoxA9 and Meis-1, two critical MLL1 target genes in MLL1 fusion protein mediated leukemogenesis. MM-102 also specifically inhibits cell growth and induces apoptosis in leukemia cells harboring MLL1 fusion proteins. Our study provides the first proof-of-concept for the design of small-molecule inhibitors of the WDR5/MLL1 protein-protein interaction as a novel therapeutic approach for acute leukemia harboring MLL1 fusion proteins. [ABSTRACT FROM AUTHOR]

Down syndrome confers a 20-fold increased risk of B cell acute lymphoblastic leukemia (B-ALL)1 and polysomy 21 is the most frequent somatic aneuploidy amongst all B-ALLs2. Yet, the mechanistic links between chr.21 triplication and B-ALL remain undefined. Here we show that germline triplication of only 31 genes orthologous to human chr.21q22 confers murine progenitor B cell self-renewal in vitro, maturation defects in vivo, and B-ALL with either BCR-ABL or CRLF2 with activated JAK2. Chr.21q22 triplication suppresses H3K27me3 in progenitor B cells and B-ALLs, and “bivalent” genes with both H3K27me3 and H3K4me3 at their promoters in wild-type progenitor B cells are preferentially overexpressed in triplicated cells. Strikingly, human B-ALLs with polysomy 21 are distinguished by their overexpression of genes marked with H3K27me3 in multiple cell types. Finally, overexpression of HMGN1, a nucleosome remodeling protein encoded on chr.21q223–5, suppresses H3K27me3 and promotes both B cell proliferation in vitro and B-ALL in vivo.

MLL1 is a histone 3 lysine 4 (H3K4) methyltransferase and a promising new cancer therapeutic target. The catalytic activity of MLL1 is regulated by the formation of a core complex consisting of MLL1, WDR5, RbBP5, and Ash2L. The interaction between WDR5 and MLL1 plays an essential role in regulation of the H3K4 methyltransferase activity of MLL1 and targeting this interaction using small molecules may represent an attractive therapeutic strategy. In this study, we have defined the essential elements in MLL1 required for its high-affinity binding to WDR5. Our data showed that the minimal elements crucial for high-affinity binding of MLL1 to WDR5 are -CO-ARA-NH- motif and two intramolecular hydrogen bonds that stabilize the conformation of this motif. Two 3-mer peptides, Ac-ARA-NH(2) and Ac-ART-NH(2), were designed based upon MLL1 and H3 sequences and achieved K(i) values of 120 and 20 nM to WDR5, respectively. Our study provides a concrete basis for the design of potent peptidomimetics and nonpeptidic compounds to inhibit MLL1 activity by targeting the MLL1 and WDR5 interaction.