Project description:BACKGROUND Antithrombotic medications target coagulation factors. Their use is associated with an increased bleeding risk. Safer drugs are needed. We described that the heat shock protein 70 (Hsp70) exhibits antithrombotic properties that do not influence bleeding. OBJECTIVES By using murine models, we want to test the hypothesis that overexpressing Hsp70 with CM-695, a dual inhibitor of HDAC6 and phosphodiesterase 9, protects against thrombosis while leaves bleeding tendency unaltered. METHODS CM-695 was used to induce Hsp70 overexpression. Hsp70 overexpressing mice were submitted to three thrombosis-triggering procedures. The ferric chloride carotid artery model was used to compare the antithrombotic role of CM-695 and rivaroxaban, a direct oral anticoagulant. The mouse tail transection model was used to compare the bleeding tendency upon CM-695 or rivaroxaban administration. RESULTS Intraperitoneal (i.p.) 20 mg/kg CM-695 increased Hsp70 expression markedly in the murine aortic tissue. This treatment delayed thrombosis in the collagen/epinephrine [P=0.04 (Log-Rank test), n=10], Rose Bengal/laser [median vessel occlusion time (OT): 58.6 vs. 39.0 minutes (min) in the control group (CG), P=0.008, n≥10] and ferric chloride (OT: 14.7 vs. 9.2 min in the CG, P=0.032, n≥10) models. I.p. 80 mg/kg CM-695 (n≥9) and intravenous 3 mg/kg rivaroxaban (n≥8) significantly delayed thrombosis. CM-695 did not induce bleeding [median bleeding time (BT): 8.5 vs. 7.5 min in the CG, n≥10]. However, this was dramatically increased by rivaroxaban (BT: 30.0 vs. 13.7 min in the CG, P=0.001, n=10). CONCLUSIONS CM-695 is a new antithrombotic drug devoid of bleeding risk that may be envisioned as a useful clinical tool.
Project description:Atrial fibrillation (AF) is a major risk factor for cardioembolic stroke. Anticoagulant drugs are effective in preventing AF-related stroke. However, the high frequency of anticoagulant-associated major bleeding is a major concern particularly when antiplatelet treatment is simultaneously administered. Here, microarray analysis in peripheral blood cells in eight patients with AF and stroke and eight AF subjects without stroke identified a stroke related gene expression pattern. HSPA1B, which encodes for heat-shock protein 70 kDa (Hsp70), was the most differentially expressed gene. This gene was downregulated in stroke subjects, a finding confirmed further in an independent AF cohort of 200 individuals. Hsp70 knock-out (KO) mice subjected to different thrombotic challenges developed thrombosis significantly earlier than their wild-type (WT) counterparts. In WT mice, Hsp70 inducers (TRC051384, or tubastatin A) delayed thrombus formation. Remarkably, Hsp70 inducers did not increase the bleeding risk even when aspirin was concomitantly administered. Hsp70 induction was associated with an increased vascular thrombomodulin expression, higher circulating levels of activated protein C (APC) upon thrombotic stimulus and increased protection against endothelial apoptosis. Thus, Hsp70 induction is a novel approach to delay thrombus formation with minimal bleeding risk, being especially promising in situations where there is a major bleeding hazard. Microarray analysis in peripheral blood cells includes eight patients with AF and stroke and eight AF subjects without stroke
Project description:Atrial fibrillation (AF) is a major risk factor for cardioembolic stroke. Anticoagulant drugs are effective in preventing AF-related stroke. However, the high frequency of anticoagulant-associated major bleeding is a major concern particularly when antiplatelet treatment is simultaneously administered. Here, microarray analysis in peripheral blood cells in eight patients with AF and stroke and eight AF subjects without stroke identified a stroke related gene expression pattern. HSPA1B, which encodes for heat-shock protein 70 kDa (Hsp70), was the most differentially expressed gene. This gene was downregulated in stroke subjects, a finding confirmed further in an independent AF cohort of 200 individuals. Hsp70 knock-out (KO) mice subjected to different thrombotic challenges developed thrombosis significantly earlier than their wild-type (WT) counterparts. In WT mice, Hsp70 inducers (TRC051384, or tubastatin A) delayed thrombus formation. Remarkably, Hsp70 inducers did not increase the bleeding risk even when aspirin was concomitantly administered. Hsp70 induction was associated with an increased vascular thrombomodulin expression, higher circulating levels of activated protein C (APC) upon thrombotic stimulus and increased protection against endothelial apoptosis. Thus, Hsp70 induction is a novel approach to delay thrombus formation with minimal bleeding risk, being especially promising in situations where there is a major bleeding hazard.
Project description:Caloric restriction (CR) without malnutrition is one of the most consistent strategies for increasing mean and maximal lifespan and delaying the onset of age-associated diseases. Stress resistance is a common trait of many long-lived mutants and life-extending interventions, including CR. Indeed, better protection against heat shock and other genotoxic insults have helped explain the pro-survival properties of CR. In this study, both in vitro and in vivo responses to heat shock were investigated using two different models of CR. Murine B16F10 melanoma cells treated with serum from CR-fed rats showed lower proliferation, increased tolerance to heat shock and enhanced HSP-70 expression, compared to serum from ad libitum-fed animals. Similar effects were observed in B16F10 cells implanted subcutaneously in male C57BL/6 mice subjected to CR. Microarray analysis identified a number of genes and pathways whose expression profile were similar in both models. These results suggest that the use of an in vitro model could be a good alternative to study the mechanisms by which CR exerts its anti-tumorigenic effects. KEY WORDS: caloric restriction, heat shock, stress response, tumorigenesis, aging
Project description:The goal of this study was the identification of a novel mode of action for this unmet need. Pharmacological tool compounds: suberoylanilide hydroxamic acid (SAHA) and tadalafil, targeting histone deacetylases (HDAC) and phosphodiesterase 5 (PDE5) respectively, were utilized simultaneously for in-vitro and in-vivo Proof-of-Concept (PoC). A synergistic effect was observed in the amelioration of AD signs using the combination therapy in Tg2576 mice. Finally, a therapeutic agent, CM-414, inhibiting simultaneously HDAC2/6 and PDE5 was generated and tested in Tg2576 mice. CM-414 reversed cognitive impairment, reduced amyloid and tau pathology, and rescued dendritic spine density loss in the hippocampus in AD mice. Importantly, the effect obtained was present after a 4-weeks wash-out period.However, to obtain a compound with a safer profile we designed a new compound, CM-695, targeting HDAC6 and PDE9. CM-695 showed similar effect to that of CM-414 after chronic administration to Tg2576 although the effect was not mantained when CM-695 was no longer administered.
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:We hypothesized that broad-scale expression profiling would provide insight into the regulatory pathways that control gene expression in response to stress, and potentially identify novel heat-responsive genes. HEp2 cells were heated at 37 to 43 °C for 60 min to gauge the heat shock response, using as a proxy inducible HSP-70 quantified by western blot analysis. Based on these results, microarray experiments were conducted at 37, 40, 41, 42 and 43°C (3 replicates/temperature x 5 groups = 15 U95Aver2 GeneChips). Using linear modeling, we compared the sets of microarrays at 40, 41, 42 and 43°C with the 37°C baseline temperature and took the union of the genes exhibiting differential gene expression signal to create two sets of “heat shock response” genes, each set reflecting either increased or decreased RNA abundance. Leveraging human and mouse orthologous alignments, we used the two lists of co-expressed genes to predict transcription factor binding sites in silico, including those for heat shock factor 1 (HSF1) and heat shock factor 2 (HSF2) transcription factors. We discovered HSF1 and HSF2 binding sites in 15 genes not previously associated with the heat shock response. We conclude that microarray experiments coupled with upstream promoter analysis can be used to identify novel genes that respond to heat shock. Additional experiments are required to validate these putative heat shock proteins and facilitate a deeper understanding of the mechanisms involved during the stress response. Keywords: stress response, temperature, human epithelial cells
Project description:We found that heat stress induces a strong and rapid YAP dephosphorylation and activation. To determin what is the physiological functions of YAP in response to heat stress, we performed RNA-SEQ analysis on siCon and siYAP/TAZ knockdown tumor cells with or without heat shock. Results indicated that 95% of heat inducible genes is blocked (83% completely and 12% partially) by YAP/TAZ knockdown in the B16-OVA melanoma cells whereas only 5% of heat inducible genes were unaffected, supporting a previously unrecognized prominent role of YAP/TAZ in the expression of the heat shock transcriptome and cell survival.
Project description:Mutants of the Mnn1 gene are hyper-sensitive to several stresses and display increased genome instability when subjected to conditions, such as heat shock, generally regarded as non-genotoxic. We describe a role for Menin as a global regulator of heat shock gene expression and critical factor in the maintenance of genome integrity 2-colour microarray design using 36 microarrays testing shock vs non shock in Drosophila melanogaster. Using a test of loss-of-heterozygosity, we show that Drosophila strains lacking a functional Mnn1 gene or expressing a Mnn1 dsRNAi are characterized by increased genome instability in response to short, repeated but non-lethal heat shock or hypoxia treatments. The same was true for strains lacking all Hsp70 genes.
Project description:Voit2003 - Trehalose Cycle
This model is described in the article:
Biochemical and genomic
regulation of the trehalose cycle in yeast: review of
observations and canonical model analysis.
Voit EO.
J. Theor. Biol. 2003 Jul; 223(1):
55-78
Abstract:
The physiological hallmark of heat-shock response in yeast
is a rapid, enormous increase in the concentration of
trehalose. Normally found in growing yeast cells and other
organisms only as traces, trehalose becomes a crucial protector
of proteins and membranes against a variety of stresses,
including heat, cold, starvation, desiccation, osmotic or
oxidative stress, and exposure to toxicants. Trehalose is
produced from glucose 6-phosphate and uridine diphosphate
glucose in a two-step process, and recycled to glucose by
trehalases. Even though the trehalose cycle consists of only a
few metabolites and enzymatic steps, its regulatory structure
and operation are surprisingly complex. The article begins with
a review of experimental observations on the regulation of the
trehalose cycle in yeast and proposes a canonical model for its
analysis. The first part of this analysis demonstrates the
benefits of the various regulatory features by means of
controlled comparisons with models of otherwise equivalent
pathways lacking these features. The second part elucidates the
significance of the expression pattern of the trehalose cycle
genes in response to heat shock. Interestingly, the genes
contributing to trehalose formation are up-regulated to very
different degrees, and even the trehalose degrading trehalases
show drastically increased activity during heat-shock response.
Again using the method of controlled comparisons, the model
provides rationale for the observed pattern of gene expression
and reveals benefits of the counterintuitive trehalase
up-regulation.
To
induce a heat shock, set the parameter heat_shock from 0 to 1. This
changes the parameter values of X8 to X19 from 1 to the values
given in table 3 of the original publication.
As
this is an S-systems model, it does not contain any reactions
encoded in SBML.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000266.
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.