PP2A-dependent TFEB activation is blocked by PIKfyve-induced mTORC1 activity

Transcriptional factor EB (TFEB) is a master regulator of genes required for autophagy and lysosomal function. The nuclear localization of TFEB is blocked by the mechanistic target of rapamycin complex 1 (mTORC1)-dependent phosphorylation of TFEB at multiple sites including Ser-211. Here we show that inhibition of PIKfyve, which produces phosphatidylinositol 3,5-bisphosphate on endosomes and lysosomes, causes a loss of Ser-211 phosphorylation and concomitant nuclear localization of TFEB. We found that while mTORC1 activity toward S6K1, as well as other major mTORC1 substrates, is not impaired, PIKfyve inhibition specifically impedes the interaction of TFEB with mTORC1. This suggests that mTORC1 activity on TFEB is selectively inhibited due to loss of mTORC1 access to TFEB. In addition, we found that TFEB activation during inhibition of PIKfyve relies on the ability of protein phosphatase 2A (PP2A) but not calcineurin/PPP3, to dephosphorylate TFEB Ser-211. Thus, when PIKfyve is inhibited, PP2A is dominant over mTORC1 for control of TFEB phosphorylation at Ser-S211. Together these findings suggest that mTORC1 and PP2A have opposing roles on TFEB via phosphorylation and dephosphorylation of Ser-211, respectively, and further, that PIKfyve inhibits TFEB activity by facilitating mTORC1-dependent phosphorylation of TFEB.

Transcriptomic changes in the pituitary of female mice with androgen excess through dihydrotestosterone (DHT) treatment

Androgen excess in women is associated with the development of PCOS and its abnormalities. The Hypothalamus Pituitary Ovarian axis signaling is altered with excessed androgens, leading to anovulation and infertility. Previous studies have shown that AR signaling in the pituitary alters gonadotrophin release. Hence, the present pioneering study was an approach to determine the transcriptomic changes responsible to the phenotype seen with DHT excess. RNA seq data showed that 583 genes were differentially regulated by DHT in pituitary, of which 344 were upregulated and 239 downregulated. Meanwhile, Transcriptional factor analysis showed that majority of the genes changed had Androgen responsive elements.

Checkpoints That Regulate Balanced Biosynthesis of Lipopolysaccharide and Its Essentiality in Escherichia coli

The outer membrane (OM) of Gram-negative bacteria, such as Escherichia coli, is essential for their viability. Lipopolysaccharide (LPS) constitutes the major component of OM, providing the permeability barrier, and a tight balance exists between LPS and phospholipids amounts as both of these essential components use a common metabolic precursor. Hence, checkpoints are in place, right from the regulation of the first committed step in LPS biosynthesis mediated by LpxC through its turnover by FtsH and HslUV proteases in coordination with LPS assembly factors LapB and LapC. After the synthesis of LPS on the inner leaflet of the inner membrane (IM), LPS is flipped by the IM-located essential ATP-dependent transporter to the periplasmic face of IM, where it is picked up by the LPS transport complex spanning all three components of the cell envelope for its delivery to OM. MsbA exerts its intrinsic hydrocarbon ruler function as another checkpoint to transport hexa-acylated LPS as compared to underacylated LPS. Additional checkpoints in LPS assembly are: LapB-assisted coupling of LPS synthesis and translocation; cardiolipin presence when LPS is underacylated; the recruitment of RfaH transcriptional factor ensuring the transcription of LPS core biosynthetic genes; and the regulated incorporation of non-stoichiometric modifications, controlled by the stress-responsive RpoE sigma factor, small RNAs and two-component systems.

A d-2-hydroxyglutarate biosensor based on specific transcriptional regulator DhdR

Abstractd-2-Hydroxyglutarate (d-2-HG) is a metabolite involved in many physiological metabolic processes. When d-2-HG is aberrantly accumulated due to mutations in isocitrate dehydrogenase or d-2-HG dehydrogenase, it functions in a pro-oncogenic manner and is thus considered a therapeutic target and biomarker in many cancers. In this study, DhdR from Achromobacter denitrificans NBRC 15125 is identified as an allosteric transcriptional factor that negatively regulates d-2-HG dehydrogenase expression and responds to the presence of d-2-HG. Based on the allosteric effect of DhdR, a d-2-HG biosensor is developed by combining DhdR with amplified luminescent proximity homogeneous assay (AlphaScreen) technology. The biosensor is able to detect d-2-HG in serum, urine, and cell culture medium with high specificity and sensitivity. Additionally, this biosensor is used to identify the role of d-2-HG metabolism in lipopolysaccharide biosynthesis of Pseudomonas aeruginosa, demonstrating its broad usages.

Activation of transcriptional factor ZBTB16 expression during osteogenic differentiation of mesenchymal stem cells

Aim. Calcified aortic valve stenosis is the third leading cause of cardiovascular disease. The mechanisms underlying this process remain unclear, however, it is known that they are largely similar to the formation of bone tissue during embryonic development, as well as in the postnatal period during regeneration. There is evidence for the involvement of Zinc Finger and BTB Domain Containing 16 (ZBTB16) in skeletal development. At the same time, a number of studies carried out on different types of cell cultures indicate a contradictory and ambiguous effect of ZBTB16 on RUNX2 expression. Thus, the aim of this study was to investigate the dynamic variability of ZBTB16 expression, as well as its role in aortic valve calcification.Methods. The study used different types of mesenchymal cells cultures - aortic valve interstitial cells, umbilical cord mesenchymal stem cells, ligament stem cells and dental pulp stem cells. Changes in ZBTB16 and RUNX2 expression levels under the influence of osteogenic stimuli, as well as during exogenous activation of ZBTB16, were analyzed using real-time PCR. Expression levels of some osteogenic markers - BMP2,4, COL1A1, IBSP, DLX2, PDK4 - were analyzed in the interstitial cells of the aortic valve.Results. The results of the study indicate that a significant increase in the expression of ZBTB16 is observed during the induction of osteogenic differentiation of various cell cultures - interstitial cells of the aortic valve, mesenchymal stem cells of the umbilical cord, stem cells of the ligaments and dental pulp. Apparently, the processes of osteogenic differentiation of aortic valve interstitial cells, in the presence of dexamethasone in cultivation medium, are provided through RUNX2-dependent signaling for the further activation of osteogenic markers.Conclusion. The study of modulation of cellular signals by ZBTB16, when activating or suppressing the work of a transcriptional factor, in the future may bring us closer to the ability to enhance the regenerative abilities of bone tissue cells or, conversely, prevent calcification of the aortic valve tissues.

Genetic Relationship of Transcriptional Factor Genes in the Regulation of Cells Death in Arabidopsis: A Review

The leaf yellowing is the first visible sign of senescence, which starts at the margins of the leaf and progresses to the blade. Although, transcriptional factor family genes generally encode meticulous regulators which perform a range of functions in turns regulating the physiological and developmental mechanism of plant stature. However, the genetic relationship of TFs genes in regulating the cell death of Arabidopsis is well not understood to date. TFs family in a plant regulates various developmental and stress responses in underline pathways. In our review we observed the genetic relationship of TFs genes in regulations of cell death in Arabidopsis. Given that, programmed cell death (PCD) being an active process that includes the expression of hundreds of genes. It is speculated that many TFs are involved in the core elements of the regulatory network. There are only a few factors that are being demonstrated in involving the regulation of cell death, by evaluating the leaf senescence appearances of knocking of mutants and by identifying downstream target genes. In this review, we have focused on the manifold roles of TFs during genetic relationships and the regulation of cell death in Arabidopsis. We also deliberated how the transcription factors family gene regulates the cells’ death by different hormonal stress, environmental strain and their role in retrograde signaling. For deep understanding of regulatory molecular mechanisms of cell death in the plant, future research may be hypothesized to collect appropriate evidence and a detailed study may be implemented on the upstream pathway with a specific targeted gene that recognizes the stress signals involved in cell death in plants. Also, crosstalk between mitochondria and chloroplast is mainly being focused to better understand the regulations of cell death in plants. Present review concludes that regulating the cell death of Arabidopsis is very important for meeting future global food needs, crop yields. Overexpression of ERF transcription factors genes relating cell death of Arabidopsis confers broad-spectrum resistance to pathogens and other abiotic stresses and can also make transgenic plants resistant to drought, salinity and freezing.

Harnessing the Therapeutic Potential of Decoys in Non-Atherosclerotic Cardiovascular Diseases: State of the Art

Cardiovascular disease (CVD) is the main cause of global death, highlighting the fact that conventional therapeutic approaches for the treatment of CVD patients are insufficient, and there is a need to develop new therapeutic approaches. In recent years, decoy technology, decoy oligodeoxynucleotides (ODN), and decoy peptides show promising results for the future treatment of CVDs. Decoy ODN inhibits transcription by binding to the transcriptional factor, while decoy peptide neutralizes receptors by binding to the ligands. This review focused on studies that have investigated the effects of decoy ODN and decoy peptides on non-atherosclerotic CVD.

Design and Prototyping of Genetically Encoded Arsenic Biosensors Based on Transcriptional Regulator AfArsR

Genetically encoded biosensors based on engineered fluorescent proteins (FPs) are essential tools for monitoring the dynamics of specific ions and molecules in biological systems. Arsenic ion in the +3 oxidation state (As3+) is highly toxic to cells due to its ability to bind to protein thiol groups, leading to inhibition of protein function, disruption of protein–protein interactions, and eventually to cell death. A genetically encoded biosensor for the detection of As3+ could potentially facilitate the investigation of such toxicity both in vitro and in vivo. Here, we designed and developed two prototype genetically encoded arsenic biosensors (GEARs), based on a bacterial As3+ responsive transcriptional factor AfArsR from Acidithiobacillus ferrooxidans. We constructed FRET-based GEAR biosensors by insertion of AfArsR between FP acceptor/donor FRET pairs. We further designed and engineered single FP-based GEAR biosensors by insertion of AfArsR into GFP. These constructs represent prototypes for a new family of biosensors based on the ArsR transcriptional factor scaffold. Further improvements of the GEAR biosensor family could lead to variants with suitable performance for detection of As3+ in various biological and environmental systems.