SETDB1 regulates microtubule dynamics.

OBJECTIVES: SETDB1 is a methyltransferase responsible for the methylation of histone H3-lysine-9, which is mainly related to heterochromatin formation. SETDB1 is overexpressed in various cancer types and is associated with an aggressive phenotype. In agreement with its activity, it mainly exhibits a nuclear localization; however, in several cell types a cytoplasmic localization was reported. Here we looked for cytoplasmic functions of SETDB1. METHODS: SETDB1 association with microtubules was detected by immunofluorescence and co-sedimentation. Microtubule dynamics were analysed during recovery from nocodazole treatment and by tracking microtubule plus-ends in live cells. Live cell imaging was used to study mitotic kinetics and protein-protein interaction was identified by co-immunoprecipitation. RESULTS: SETDB1 co-sedimented with microtubules and partially colocalized with microtubules. SETDB1 partial silencing led to faster polymerization and reduced rate of catastrophe events of microtubules in parallel to reduced proliferation rate and slower mitotic kinetics. Interestingly, over-expression of either wild-type or catalytic dead SETDB1 altered microtubule polymerization rate to the same extent, suggesting that SETDB1 may affect microtubule dynamics by a methylation-independent mechanism. Moreover, SETDB1 co-immunoprecipitated with HDAC6 and tubulin acetylation levels were increased upon silencing of SETDB1. CONCLUSIONS: Taken together, our study suggests a model in which SETDB1 affects microtubule dynamics by interacting with both microtubules and HDAC6 to enhance tubulin deacetylation. Overall, our results suggest a novel cytoplasmic role for SETDB1 in the regulation of microtubule dynamics.

Phytochemical Screening, Quantification, FT-IR Analysis, and In Silico Characterization of Potential Bio-active Compounds Identified in HR-LC/MS Analysis of the Polyherbal Formulation from Northeast India.

Diabetes is a group of metabolic disorders characterized by elevated blood sugar levels, leading to many undesirable health consequences. There are many herbal formulations, traditionally used by the Northeast Indian population for disease management. These formulations require scientific validations to optimize their efficacy and increase their popularity. In this study, we attempt to scientifically validate a polyherbal formulation traditionally used for the management of diabetes through preliminary phytochemicals investigation, characterization of potential phytochemicals using Fourier transform infrared (FT-IR) spectroscopy, high-resolution liquid chromatography mass spectrometry (HR-LC/MS) analysis, and in silico characterization of physiochemical, drug-likeness, and pharmacokinetic properties of identified phytochemical compounds. Qualitative phytochemical screening of various extracts of the formulation confirmed the presence of alkaloids, phenols and tannins, flavonoids, fats, and oils. Phytochemical quantification of the various extracts showed that the highest total phenolic content is present in the ethanolic extract (35.61 ± 0.15 mg GAE/g), while the highest total flavonoid content is present in the chloroform extract (76.33 ± 2.96 mg QE/g) of the formulation. FT-IR spectroscopic analysis revealed various characteristic band values with various functional groups in the formulation extract such as amines, alcohol, fluoro compounds, phenol, alkane, alkene, and conjugated acid groups. HR-LC/MS analyses identified nearly 51 compounds including 9 small peptides and 42 potential phytochemical compounds. In silico SwissADME analysis of identified compounds revealed 25 potential compounds following Lipinski's rule and showing drug-like characteristics, and out of them, 16 compounds exhibited good oral bioavailability, as revealed in the bioavailability radar. The overall study showed that the presented polyherbal formulation is enriched with bio-active phytochemical compounds with good pharmaceutical values.

Cobalt oxide (Co3O4) nanoparticles induced genotoxicity in Chinese hamster lung fibroblast (V79) cells through modulation of reactive oxygen species.

Incessant production, pervasive applications in different fields, and eventually unintended exposure of cobalt oxide nanoparticles (Co3O4 NPs) lead to rise in their toxicity studies toward human health. However, the information regarding the potential toxicity mechanisms of Co3O4 NPs especially genotoxicity is still sparse with missing interconnections. So far, only solitary reports on Co3O4 NPs are at hand, bearing witness to reactive oxygen species (ROS)-mediated DNA damage in lung cells. To address this, we evaluated the Co3O4 NP-induced cytotoxic and genotoxic potential in Chinese hamster lung fibroblast cell line (V79). Our preliminary results demonstrate that Co3O4 NPs at concentrations of 20-100 µg/ml induced moderate mortality after 24-h exposure. However, these low concentrations caused a significant reduction in various organelles' activity in a concentration-dependent manner. Mitochondrial activity and membrane potential were found to be compromised due to NP exposure in a concentration-dependent manner. The study affirms that Co3O4 NPs inhibited lysosomal activity in V79 cells. In addition to this, Co3O4 NPs are also found to stimulate free oxygen radical generation. Genotoxicity studies revealed a potent and dose-dependent effect of non-cytotoxic concentrations of Co3O4 NPs in the induction of DNA lesions. Interestingly, N-acetylcysteine, a free oxygen radical scavenger (5, 10 mM, pretreatment) inhibited the progression of free oxygen radicals and induction of Co3O4 NP-mediated DNA lesions. This suggests the ROS-mediated genotoxic potential of Co3O4 NPs.