The Effects of Diethyldithiocarbamate (DDC) on the Astrocytic Cytoskeleton

The dithiocarbamates are a group of compounds that are used extensively in industry, agriculture and medicine. Exposure to these compounds has caused deleterious effects to both the central and peripheral nervous systems. Cultured rat hippocampal astroglia treated with 35 μg/ml diethyldithiocarbamate (DDC) in media were studied for alterations to the cytoskeleton. Examination by both immunohistochemistry and scanning electron microscopy revealed disruption of the cytoskeletal elements. This occurred in a progressive time-dependent manner. Electrophoretic patterns demonstrated two cytoskeletal protein alterations. The microtubular protein, β-tubulin, appeared to have an altered mobility while the major intermediate filament protein, glial fibrillary acidic protein (GF AP), was decreased. The cytoskeleton appears to be an important cellular target for injury by DDC exposure. This study has demonstrated that DDC induces alterations in the architecture of the cytoskeleton of astroglia and suggests that these changes involve microtubular and intermediate filament proteins

Single-cell RNA-seq highlights intratumoral heterogeneity in primary glioblastoma

Human cancers are complex ecosystems composed of cells with distinct phenotypes, genotypes, and epigenetic states, but current models do not adequately reflect tumor composition in patients. We used single-cell RNA sequencing (RNA-seq) to profile 430 cells from five primary glioblastomas, which we found to be inherently variable in their expression of diverse transcriptional programs related to oncogenic signaling, proliferation, complement/immune response, and hypoxia. We also observed a continuum of stemness-related expression states that enabled us to identify putative regulators of stemness in vivo. Finally, we show that established glioblastoma subtype classifiers are variably expressed across individual cells within a tumor and demonstrate the potential prognostic implications of such intratumoral heterogeneity. Thus, we reveal previously unappreciated heterogeneity in diverse regulatory programs central to glioblastoma biology, prognosis, and therapy.National Institutes of Health (U.S.) (U24 CA180922

Chrysin Ameliorates Cyclosporine-A-Induced Renal Fibrosis by Inhibiting TGF-β1-Induced Epithelial–Mesenchymal Transition

Cyclosporine A (CsA) is a nephrotoxicant that causes fibrosis via induction of epithelial–mesenchymal transition (EMT). The flavonoid chrysin has been reported to have anti-fibrotic activity and inhibit signaling pathways that are activated during EMT. This study investigated the nephroprotective role of chrysin in the prevention of CsA-induced renal fibrosis and elucidated a mechanism of inhibition against CsA-induced EMT in proximal tubule cells. Treatment with chrysin prevented CsA-induced renal dysfunction in Sprague Dawley rats measured by blood urea nitrogen (BUN), serum creatinine and creatinine clearance. Chrysin inhibited CsA-induced tubulointerstitial fibrosis, characterized by reduced tubular damage and collagen deposition. In vitro, chrysin significantly inhibited EMT in LLC-PK1 cells, evidenced by inhibition of cell migration, decreased collagen expression, reduced presence of mesenchymal markers and elevated epithelial junction proteins. Furthermore, chrysin co-treatment diminished CsA-induced TGF-β1 signaling pathways, decreasing Smad 3 phosphorylation which lead to a subsequent reduction in Snail expression. Chrysin also inhibited activation of the Akt/ GSK-3β pathway. Inhibition of both pathways diminished the cytosolic accumulation of β-catenin, a known trigger for EMT. In conclusion, flavonoids such as chrysin offer protection against CsA-induced renal dysfunction and interstitial fibrosis. Chrysin was shown to inhibit CsA-induced TGF-β1-dependent EMT in proximal tubule cells by modulation of Smad-dependent and independent signaling pathways

Discovery and Structure–Activity Relationship of Novel 2,3-Dihydrobenzofuran-7-carboxamide and 2,3-Dihydrobenzofuran-3(2<i>H</i>)‑one-7-carboxamide Derivatives as Poly(ADP-ribose)polymerase‑1 Inhibitors

Novel substituted 2,3-dihydrobenzofuran-7-carboxamide (DHBF-7-carboxamide) and 2,3-dihydrobenzofuran-3­(2<i>H</i>)-one-7-carboxamide (DHBF-3-one-7-carboxamide) derivatives were synthesized and evaluated as inhibitors of poly­(ADP-ribose)­polymerase-1 (PARP-1). A structure-based design strategy resulted in lead compound <b>3</b> (DHBF-7-carboxamide; IC₅₀ = 9.45 μM). To facilitate synthetically feasible derivatives, an alternative core was designed, DHBF-3-one-7-carboxamide (<b>36</b>, IC₅₀ = 16.2 μM). The electrophilic 2-position of this scaffold was accessible for extended modifications. Substituted benzylidene derivatives at the 2-position were found to be the most potent, with 3′,4′-dihydroxybenzylidene <b>58</b> (IC₅₀ = 0.531 μM) showing a 30-fold improvement in potency. Various heterocycles attached at the 4′-hydroxyl/4′-amino of the benzylidene moiety resulted in significant improvement in inhibition of PARP-1 activity (e.g., compounds <b>66</b>–<b>68</b>, <b>70</b>, <b>72</b>, and <b>73</b>; IC₅₀ values from 0.718 to 0.079 μM). Compound <b>66</b> showed selective cytotoxicity in <i>BRCA</i>2-deficient DT40 cells. Crystal structures of three inhibitors (compounds (<b>−</b>)<b>-13c</b>, <b>59</b>, and <b>65</b>) bound to a multidomain PARP-1 structure were obtained, providing insights into further development of these inhibitors