The transcriptional activity of hepatocyte nuclear factor 4 alpha is inhibited via phosphorylation by ERK1/2

Hepatocyte nuclear factor 4 alpha (HNF4alpha) nuclear receptor is a master regulator of hepatocyte development, nutrient transport and metabolism. HNF4alpha is regulated both at the transcriptional and post-transcriptional levels by different mechanisms. Several kinases (PKA, PKC, AMPK) were shown to phosphorylate and decrease the activity of HNF4alpha. Activation of the ERK1/2 signalling pathway, inducing proliferation and survival, inhibits the expression of HNF4alpha. However, based on our previous results we hypothesized that HNF4alpha is also regulated at the post-transcriptional level by ERK1/2. Here we show that ERK1/2 is capable of directly phosphorylating HNF4alpha in vitro at several phosphorylation sites including residues previously shown to be targeted by other kinases, as well. Furthermore, we also demonstrate that phosphorylation of HNF4alpha leads to a reduced trans-activational capacity of the nuclear receptor in luciferase reporter gene assay. We confirm the functional relevance of these findings by demonstrating with ChIP-qPCR experiments that 30-minute activation of ERK1/2 leads to reduced chromatin binding of HNF4alpha. Accordingly, we have observed decreasing but not disappearing binding of HNF4alpha to the target genes. In addition, 24-hour activation of the pathway further decreased HNF4alpha chromatin binding to specific loci in ChIP-qPCR experiments, which confirms the previous reports on the decreased expression of the HNF4a gene due to ERK1/2 activation. Our data suggest that the ERK1/2 pathway plays an important role in the regulation of HNF4alpha-dependent hepatic gene expression

The effect of processing on the mechanical properties of the polycarbonate composites with glass fiber

Celem przeprowadzonych badań było określenie wpływu przetwórstwa na właściwości mechaniczne kompozytu na osnowie poliwęglanu modyfikowanego włóknem szklanym. Kompozyt został poddany przetwórstwu dwiema metodami wytłaczania jedno oraz dwuślimakowego współbieżnego w celu otrzymania zróżnicowanych warunków obciążeń termomechanicznych. Wpływ warunków przetwórczych na właściwości wtryskiwanych wyrobów oceniono na podstawie przeprowadzonej próby statycznego rozciągania oraz udarności metodą DYNSTAT. Badania uzupełnione zostały o ocenę struktury kompozytów poddanych obciążeniom termomechanicznym za pomocą Skaningowej Mikroskopii Elektronowej (SEM).The aim of the study was to determine the effect of processing on the mechanical properties of the polycarbonate composites with glass fiber. The composite material was processed by two various extrusion methods: one and twin-screw extrusion using in the secondmethod the co-extruder, in order to obtain different thermo-mechanical loading conditions. Influence of processing conditions on the properties of injection-molded products has been evaluated on the basis of static tensile and the DYNSTAT impact tests. Tests were supplemented by an assessment of structures of polycarbonate compositestreated by thermo-mechanical loads using the Scanning Electron Microscopy (SEM)

Anticancer imidazoacridinone C-1311 is effective in androgen-dependent and androgen-independent prostate cancer cells

The androgen receptor (AR) plays a critical role in prostate cancer (PCa) development and metastasis. Thus, blocking AR activity and its downstream signaling constitutes a major strategy for PCa treatment. Here, we report on the potent anti-PCa activity of a small-molecule imidazoacridinone, C-1311. In AR-positive PCa cells, C-1311 was found to inhibit the transcriptional activity of AR, uncovering a novel mechanism that may be relevant for its anticancer effect. Mechanistically, C-1311 decreased the AR binding to the prostate-specific antigen (<i>PSA</i>) promoter, reduced the PSA protein level, and, as shown by transcriptome sequencing, downregulated numerous AR target genes. Importantly, AR-negative PCa cells were also sensitive to C-1311, suggesting a promising efficacy in the androgen-independent PCa sub-type. Irrespective of AR status, C-1311 induced DNA damage, arrested cell cycle progression, and induced apoptosis. RNA sequencing indicated significant differences in the transcriptional response to C-1311 between the PCa cells. Gene ontology analysis showed that in AR-dependent PCa cells, C-1311 mainly affected the DNA damage response pathways. In contrast, in AR-independent PCa cells, C-1311 targeted the cellular metabolism and inhibited the genes regulating glycolysis and gluconeogenesis. Together, these results indicate that C-1311 warrants further development for the treatment of PCa

NFAT primes the human RORC locus for RORγt expression in CD4 + T cells

International audienceT helper 17 (Th17) cells have crucial functions in mucosal immunity and the pathogenesis of several chronic inflammatory diseases. The lineage-specific transcription factor, RORγt, encoded by the RORC gene modulates Th17 polarization and function, as well as thymocyte development. Here we define several regulatory elements at the human RORC locus in thy-mocytes and peripheral CD4 + T lymphocytes, with CRISPR/Cas9-guided deletion of these genomic segments supporting their role in RORγt expression. Mechanistically, T cell receptor stimulation induces cyclosporine A-sensitive histone modifications and P300/CBP acetylase recruitment at these elements in activated CD4 + T cells. Meanwhile, NFAT proteins bind to these regulatory elements and activate RORγt transcription in cooperation with NF-kB. Our data thus demonstrate that NFAT specifically regulate RORγt expression by binding to the RORC locus and promoting its permissive conformation