Project description:During heat stress cyto-protective genes including heat shock proteins are transcriptionally up-regulated and post-transcriptional splicing is inhibited. In contrast, co-transcriptional mRNA-splicing is maintained. These factors closely resemble the proteotoxic stress response during tumor development. The bromodomain protein BRD4 has been identified as an integral member of the oxidative stress as well as of the inflammatory response. Furthermore, there is evidence for BRD4's role in splicing regulation; Using RNA-Seq analyses we indeed found a significant increase in splicing inhibition, in particular intron retentions, during heat treatment in BRD4-deficient cells, but not under normal conditions. Subsequent experiments revealed that heat stress leads to the recruitment of BRD4 to nuclear stress bodies, to the interaction with the heat shock factor 1 (HSF1) and to the transcriptional up-regulation of non-coding Sat III RNA transcripts. These findings implicate BRD4 as a central regulator of splicing during heat stress. Since BRD4 is a potent target for anti-cancer therapies, our data linking BRD4 to the splicing machinery and the heat stress response - give additional insight into the mode of action of BRD4 inhibitors. WI38 cells have been treated by heatshock and anti BRD4 siRNA and combination.
Project description:During heat stress cyto-protective genes including heat shock proteins are transcriptionally up-regulated and post-transcriptional splicing is inhibited. In contrast, co-transcriptional mRNA-splicing is maintained. These factors closely resemble the proteotoxic stress response during tumor development. The bromodomain protein BRD4 has been identified as an integral member of the oxidative stress as well as of the inflammatory response. Furthermore, there is evidence for BRD4's role in splicing regulation; Using RNA-Seq analyses we indeed found a significant increase in splicing inhibition, in particular intron retentions, during heat treatment in BRD4-deficient cells, but not under normal conditions. Subsequent experiments revealed that heat stress leads to the recruitment of BRD4 to nuclear stress bodies, to the interaction with the heat shock factor 1 (HSF1) and to the transcriptional up-regulation of non-coding Sat III RNA transcripts. These findings implicate BRD4 as a central regulator of splicing during heat stress. Since BRD4 is a potent target for anti-cancer therapies, our data linking BRD4 to the splicing machinery and the heat stress response - give additional insight into the mode of action of BRD4 inhibitors.
Project description:By targeted depletion of Cohesin (RAD21 subunit) or BRD4 alone or together, we have established that cohesin alone or with BRD4 regulates the alternative splicing of a large subset of genes under both physiological and heat shock conditions.
Project description:Bromodomain-containing Protein 4 (BRD4) is a transcriptional regulator associated with cancer biology, inflammation, and fibrosis. In airway viral infection, non-toxic BRD4-specific inhibitors (BRD4i) block the release of pro- inflammatory cytokines and prevent downstream remodeling. Although the chromatin modifying functions of BRD4 in inducible gene expression have been extensively investigated, its roles in post-transcriptional regulation are not as well understood. Based on its interaction with transcriptional elongation complex and spiceosome, we hypothesize that BRD4 is a functional regulator of RNA processing. To address this question, we combine data-independent analysis - parallel accumulation-serial fragmentation (diaPASEF) with RNA-sequencing to achieve deep coverage of the proteomic and transcriptomic landscape of human small airway epithelial cells exposed to viral challenge and treated with BRD4i. The transcript-level data was further interrogated for alternative splicing analysis, and the resulting data sets were correlated to identify pathways subject to post-transcriptional regulation. We discover that BRD4 regulates alternative splicing of key genes, including Interferon-related Developmental Regulator 1 (IFRD1) and X-Box Binding Protein 1 (XBP1), related to the innate immune response and the unfolded protein response, respectively. These findings extend the actions of BRD4 in control of post-transcriptional RNA processing.
Project description:Proctor2005 - Actions of chaperones and their
role in ageing
This model is described in the article:
Modelling the actions of
chaperones and their role in ageing.
Proctor CJ, Soti C, Boys RJ,
Gillespie CS, Shanley DP, Wilkinson DJ, Kirkwood TB.
Mech. Ageing Dev. 2005 Jan; 126(1):
119-131
Abstract:
Many molecular chaperones are also known as heat shock
proteins because they are synthesised in increased amounts
after brief exposure of cells to elevated temperatures. They
have many cellular functions and are involved in the folding of
nascent proteins, the re-folding of denatured proteins, the
prevention of protein aggregation, and assisting the targeting
of proteins for degradation by the proteasome and lysosomes.
They also have a role in apoptosis and are involved in
modulating signals for immune and inflammatory responses.
Stress-induced transcription of heat shock proteins requires
the activation of heat shock factor (HSF). Under normal
conditions, HSF is bound to heat shock proteins resulting in
feedback repression. During stress, cellular proteins undergo
denaturation and sequester heat shock proteins bound to HSF,
which is then able to become transcriptionally active. The
induction of heat shock proteins is impaired with age and there
is also a decline in chaperone function. Aberrant/damaged
proteins accumulate with age and are implicated in several
important age-related conditions (e.g. Alzheimer's disease,
Parkinson's disease, and cataract). Therefore, the balance
between damaged proteins and available free chaperones may be
greatly disturbed during ageing. We have developed a
mathematical model to describe the heat shock system. The aim
of the model is two-fold: to explore the heat shock system and
its implications in ageing; and to demonstrate how to build a
model of a biological system using our simulation system
(biology of ageing e-science integration and simulation
(BASIS)).
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000091.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:Developmental transitions are guided by master regulatory transcription factors. During adipogenesis, a transcriptional cascade culminates in expression of PPARg and C/EBPa, which orchestrate activation of the adipocyte gene expression program. However, the coactivators controlling PPARg and C/EBPa expression are less well characterized. Here we show the bromodomain-containing protein, BRD4, regulates transcription of PPARg and C/EBPa. Analysis of BRD4 chromatin occupancy reveals that induction of adipogenesis in 3T3L1 fibroblasts provokes dynamic redistribution of BRD4 to de novo super enhancers proximal to genes controlling adipocyte differentiation. BET bromodomain inhibition impedes BRD4 occupancy at these de novo enhancers and disrupts transcription of Pparg and Cebpa, thereby blocking adipogenesis. Furthermore, silencing of these BRD4-occupied distal regulatory elements at the Pparg locus by CRISPRi demonstrates a critical role for these enhancers in the control of Pparg gene expression and adipogenesis in 3T3L1s. Together, these data establish BET bromodomain proteins as time- and context-dependent coactivators of the adipocyte cell state transition.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.