HSF1 Overexpression Research Articles

Activation of the heat shock response as a therapeutic strategy for tau toxicity.

Alzheimer's disease is associated with the misfolding and aggregation of two distinct proteins, beta-amyloid and tau. Previously, it has been shown that activation of the cytoprotective heat shock response (HSR) pathway reduces beta-amyloid toxicity. Here, we show that activation of the HSR is also protective against tau toxicity in a cell-autonomous manner. Overexpression of HSF-1, the master regulator of the HSR, ameliorates the motility defect and increases the lifespan of transgenic C. elegans expressing human tau. By contrast, RNA interference of HSF-1 exacerbates the motility defect and shortens lifespan. Targeting regulators of the HSR also affects tau toxicity. Additionally, two small-molecule activators of the HSR, Geranylgeranylacetone (GGA) and Arimoclomol (AC), have substantial beneficial effects. Taken together, this research expands the therapeutic potential of HSR manipulation to tauopathies and reveals that the HSR can impact both beta-amyloid and tau proteotoxicity in Alzheimer's disease.

Spliceosome component Usp39 contributes to hepatic lipid homeostasis through the regulation of autophagy

Regulation of alternative splicing (AS) enables a single transcript to yield multiple isoforms that increase transcriptome and proteome diversity. Here, we report that spliceosome component Usp39 plays a role in the regulation of hepatocyte lipid homeostasis. We demonstrate that Usp39 expression is downregulated in hepatic tissues of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) subjects. Hepatocyte-specific Usp39 deletion in mice leads to increased lipid accumulation, spontaneous steatosis and impaired autophagy. Combined analysis of RNA immunoprecipitation (RIP-seq) and bulk RNA sequencing (RNA-seq) data reveals that Usp39 regulates AS of several autophagy-related genes. In particular, deletion of Usp39 results in alternative 5’ splice site selection of exon 6 in Heat shock transcription factor 1 (Hsf1) and consequently its reduced expression. Importantly, overexpression of Hsf1 could attenuate lipid accumulation caused by Usp39 deficiency. Taken together, our findings indicate that Usp39-mediated AS is required for sustaining autophagy and lipid homeostasis in the liver.

An Increase in HSF1 Expression Directs Human Mammary Epithelial Cells toward a Mesenchymal Phenotype.

HSF1 is a well-known heat shock protein expression regulator in response to stress. It also regulates processes important for growth, development or tumorigenesis. We studied the HSF1 influence on the phenotype of non-tumorigenic human mammary epithelial (MCF10A and MCF12A) and several triple-negative breast cancer cell lines. MCF10A and MCF12A differ in terms of HSF1 levels, morphology, growth in Matrigel, expression of epithelial (CDH1) and mesenchymal (VIM) markers (MCF10A are epithelial cells; MCF12A resemble mesenchymal cells). HSF1 down-regulation led to a reduced proliferation rate and spheroid formation in Matrigel by MCF10A cells. However, it did not affect MCF12A proliferation but led to CDH1 up-regulation and the formation of better organized spheroids. HSF1 overexpression in MCF10A resulted in reduced CDH1 and increased VIM expression and the acquisition of elongated fibroblast-like morphology. The above-mentioned results suggest that elevated levels of HSF1 may direct mammary epithelial cells toward a mesenchymal phenotype, while a lowering of HSF1 could reverse the mesenchymal phenotype to an epithelial one. Therefore, HSF1 may be involved in the remodeling of mammary gland architecture over the female lifetime. Moreover, HSF1 levels positively correlated with the invasive phenotype of triple-negative breast cancer cells, and their growth was inhibited by the HSF1 inhibitor DTHIB.

HSF1 enhances the attenuation of exosomes from mesenchymal stem cells to hemorrhagic shock induced lung injury by altering the protein profile of exosomes

Severe hemorrhagic shock (HS) leads to lung injury, resulting in respiratory insufficiency. Mesenchymal stem cell (MSC)-derived exosomes have therapeutic effects on the organ injury. HSF1 has been reported to protect the lung against injury. In this study, the role of exosomes from HSF1-overexpressed MSCs (HSF1-EVs) in HS-induced lung injury was investigated. We constructed a mouse model of lung injury by induction with HS and pre-treated it with HSF1-EVs. It was clarified that HSF1-EVs manifested better protective effects on HS-induced lung injury compared with the exosomes derived from control MSCs. Inhalation of HSF1-EVs declined the ratio of wet to dry and total protein concentration in bronchoalveolar lavage fluids. Besides, HSF1-EVs greatly inhibited the production of inflammatory cytokines (IL-1β, IL-6, MCP-1 and HMGB1), and constrained the pulmonary neutrophilic infiltration induced by HS. A reduction of oxidative stress was observed in HSF1-EV-treated mice. HSF1-EVs suppressed the HS-induced apoptosis of lung cell and downregulated Bcl-2 expression, while promoting Bax expression. The key proteins of pulmonary epithelial barrier, E-cadherin, ZO-1 and Occludin, were all upregulated in HS-treated mice after HSF1-EV inhalation, suggesting that HSF1-EVs played a protective role in the epithelial barrier of lung. Additionally, the results of proteomics showed that HSF1 overexpression altered the protein profile of MSC-derived exosomes, which might explain the more significant relief effect of HSF1-EVs on lung injury compared with that of Plasmid-EVs. These new findings demonstrated that the exosomes secreted by HSF1-overexpressed MSCs can be an effective precautionary measure for lung injury induced by HS.

Genome-wide analysis reveals Hsf1 maintains high transcript abundance of target genes controlled by strong constitutive promoter in Saccharomyces cerevisiae

BackgroundIn synthetic biology, the strength of promoter elements is the basis for precise regulation of target gene transcription levels, which in turn increases the yield of the target product. However, the results of many researches proved that excessive transcription levels of target genes actually reduced the yield of the target product. This phenomenon has been found in studies using different microorganisms as chassis cells, thus, it becomes a bottleneck problem to improve the yield of the target product.ResultsIn this study, promoters PGK1p and TDH3p with different strengths were used to regulate the transcription level of alcohol acetyl transferase encoding gene ATF1. The results demonstrated that the strong promoter TDH3p decreased the production of ethyl acetate. The results of Real-time PCR proved that the transcription level of ATF1 decreased rapidly under the control of TDH3p, and the unfolded protein reaction was activated, which may be the reason for the abnormal production caused by the strong promoter. RNA-sequencing analysis showed that the overexpression of differential gene HSP30 increased the transcriptional abundance of ATF1 gene and production of ethyl acetate. Interestingly, deletion of the heat shock protein family (e.g., Hsp26, Hsp78, Hsp82) decreased the production of ethyl acetate, suggesting that the Hsp family was also involved in the regulation of ATF1 gene transcription. Furthermore, the results proved that the Hsf1, an upstream transcription factor of Hsps, had a positive effect on alleviating the unfolded protein response and that overexpression of Hsf1 reprogramed the pattern of ATF1 gene transcript levels. The combined overexpression of Hsf1 and Hsps further increased the production of ethyl acetate. In addition, kinase Rim15 may be involved in this regulatory pathway. Finally, the regulation effect of Hsf1 on recombinant strains constructed by other promoters was verified, which confirmed the universality of the strategy.ConclusionsOur results elucidated the mechanism by which Rim15–Hsf1–Hsps pathway reconstructed the repression of high transcription level stress and increased the production of target products, thereby providing new insights and application strategies for the construction of recombinant strains in synthetic biology.

Expression profiling of heat shock protein genes in whole blood of Romosinuano cattle breed

Background and Aim: Heat shock proteins are highly conserved proteins that work as molecular chaperones expressed in response to thermal stress. This study aimed to determine the expression profile of genes related to the heat stress response in whole blood obtained from the Romosinuano creole breed. Materials and Methods: Real-time polymerase chain reaction was performed to analyze the transcript of hsp90, hsp70, hsp60, and hsf1 in the whole blood of Romosinuano under different temperature-humidity indices (THIs). Results: The expression levels of the hsp70 and hsf1 genes at the high-THI level were higher (p = 0.0011 and p = 0.0003, respectively) than those at the low-THI level. In addition, no differences in the expression levels of the hsp60 and hsP90 genes were detected between the two THIs. Conclusion: The overexpression of hsf1 and hsp70 genes play an important role in protecting cells from damage induced by heat stress. Keywords: climate change, external environment, heat shock proteins, heat stress, mRNA, temperature-humidity index.

Expression profiling of heat shock protein genes in whole blood of Romosinuano cattle breed.

Heat shock proteins are highly conserved proteins that work as molecular chaperones expressed in response to thermal stress. This study aimed to determine the expression profile of genes related to the heat stress response in whole blood obtained from the Romosinuano creole breed. Real-time polymerase chain reaction was performed to analyze the transcript of hsp90, hsp70, hsp60, and hsf1 in the whole blood of Romosinuano under different temperature-humidity indices (THIs). The expression levels of the hsp70 and hsf1 genes at the high-THI level were higher (p = 0.0011 and p = 0.0003, respectively) than those at the low-THI level. In addition, no differences in the expression levels of the hsp60 and hsP90 genes were detected between the two THIs. The overexpression of hsf1 and hsp70 genes play an important role in protecting cells from damage induced by heat stress.

Glia of C. elegans coordinate a protective organismal heat shock response independent of the neuronal thermosensory circuit.

Aging organisms lose the ability to induce stress responses, becoming vulnerable to protein toxicity and tissue damage. Neurons can signal to peripheral tissues to induce protective organelle-specific stress responses. Recent work shows that glia can independently induce such responses. Here, we show that overexpression of heat shock factor 1 (hsf-1) in the four astrocyte-like cephalic sheath cells of Caenorhabditis elegans induces a non-cell-autonomous cytosolic unfolded protein response, also known as the heat shock response (HSR). These animals have increased lifespan and heat stress resistance and decreased protein aggregation. Glial HSR regulation is independent of canonical thermosensory circuitry and known neurotransmitters but requires the small clear vesicle release protein UNC-13. HSF-1 and the FOXO transcription factor DAF-16 are partially required in peripheral tissues for non-cell-autonomous HSR, longevity, and thermotolerance. Cephalic sheath glial hsf-1 overexpression also leads to pathogen resistance, suggesting a role for this signaling pathway in immune function.

MicroRNA-455-3p inhibits osteosarcoma progression via HSF1 downregulation

ObjectiveThis study was conducted to dissect the role and potential mechanism of microRNA (miR)-455-3p on osteosarcoma (OS) development. MethodsmiR-455-3p and HSF1 expression in OS tissues were detected by RT-qPCR and western blot. Later, gain- and loss-of-function assays were implemented in OS cells U–2OS and MNNG. The expression of apoptosis-related genes was measured by RT-qPCR and western blot. MTT, Transwell, scratch test, and flow cytometry were utilized to test OS cell viability, invasion, migration, and apoptosis. The targeting relationship between miR-455-3p and HSF1 was assessed with a dual-luciferase reporter gene assay. The transplantation tumor experiment in nude mice was utilized for in vivo confirmation. ResultsDownregulated miR-455-3p and upregulated HSF1 were displayed in OS tissues and cells. Mechanistically, miR-455-3p negatively targeted HSF1. MiR-455-3p inhibition or HSF1 overexpression increased MNNG and U–2OS cell proliferative, invasive, and migrating capabilities, while diminishing U–2OS cell apoptosis. Moreover, HSF1 overexpression negated the impacts of miR-455-3p upregulation on OS cell proliferative, invasive, migrating, and apoptotic abilities. Likewise, overexpressing miR-455-3p curtailed the growth of transplanted OS tumors through HSF1 repression. ConclusionMiR-455-3p inhibits the development of OS cells by downregulating HSF1, highlighting the possibility of miR-455-3p as an innovative indicator of prognosis and a therapeutic target for OS.

Mechanism of miR-455-3 in suppressing epithelial-mesenchymal transition and angiogenesis of non-small cell lung cancer cells.

The tumor-suppressing role of miR-455-3p has been reported in lung cancer, but the working mechanism remains to be fully elucidated. This study aims to explore the possible mechanism of miR-455-3p in regulating epithelial-mesenchymal transition (EMT) progression and angiogenesis in non-small cell lung cancer (NSCLC) cells.The expressions of miR-455-3p, HSF1, GLS1, and EMT-related proteins (E-cadherin, N-cadherin, vimentin, and Snail-1) in both NSCLC tissues and cell lines were determined by RT-qPCR and western blot. After cell transfection, cell proliferation and angiogenesis ability on NSCLC cells were assessed by MTT and tube formation assay. The binding of miR-455-3p with HSF1 was measured by luciferase reporter gene assay, while the interaction between HSF1 and GLS1 was determined by co-immunoprecipitation assay (Co-IP).HSF1 was highly expressed in NSCLC tissues and cells. Inhibition of HSF1 expression or overexpression of miR-455-3p in NSCLC cells can suppress cell proliferation, angiogenesis ability, and EMT progression. miR-455-3p was found to negatively regulate HSF1 expression. Co-transfection of miR-455-3p overexpression and HSF1 inhibition in NSCLC cells showed that miR-455-3p can partially counteract the effect of HSF1 in NSCLC cells. HSF1 can interact with GLS1 and elevate the expression of GLS1. GLS1 can partially abolish the suppressive effect of miR-455-3p in NSCLC cells.miR-455-3p can bind HSF1 to suppress the GLS1 in NSCLC cells, therefore suppressing EMT progression and angiogenesis of NSCLC cells.

Vinyl-Stilbene Inhibits Human Norovirus RNA Replication by Activating Heat-Shock Factor-1.

Norovirus (NV) is the most common cause of viral gastroenteritis, with the potential to develop into a fatal disease in those who are immuno-compromised, and effective vaccines and treatments are still non-existent. In this study, we aimed to elucidate the molecular mechanism of the previously identified NV replication inhibitor utilizing a vinyl-stilbene backbone, AC-1858. First, we confirmed the inhibition of the NV RNA replication by a structural analog of AC-1858, AC-2288 with its exclusive cytoplasmic subcellular localization. We further validated the induction of one specific host factor, the phosphorylated form of heat shock factor (HSF)-1, and its increased nuclear localization by AC-1858 treatment. Finally, we verified the positive and negative impact of the siRNA-mediated downregulation and lentivirus-mediated overexpression of HSF-1 on NV RNA replication. In conclusion, these data suggest the restrictive role of the host factor HSF-1 in overall viral RNA genome replication during the NV life cycle.

HSF1-Dependent Autophagy Activation Contributes to the Survival of Melanocytes Under Oxidative Stress in Vitiligo

Autophagy plays a protective role in oxidative stress‒induced melanocyte death. Dysregulated autophagy increases the sensitivity of melanocytes in response to oxidative damage and promotes melanocyte degeneration in vitiligo. However, the molecular mechanism underlying this process is not fully understood. In this study, using RNA-sequencing technology, we compared the transcriptome change between normal and vitiligo melanocytes with or without treatment of oxidative stress. We found that ATG5 and ATG12, the critical components for autophagosome formation, were significantly reduced in vitiligo melanocytes under oxidative stress. Mechanistically, HSF1 is the prime transcription factor for both ATG5 and ATG12, accounting for the reduced level of ATG5 and ATG12 in vitiligo melanocytes. Deficiency of HSF1 led to accumulation of intracellular ROS, imbalance of mitochondrion membrane potential, and apoptosis in melanocytes exposure to oxidative stress. Furthermore, overexpression of HSF1 could ameliorate oxidative stress‒induced melanocytes death through the activation of autophagy by upregulating ATG5 and ATG12. These findings suggested that targeting HSF1-ATG5/12 axis could prevent oxidative stress‒induced melanocyte death and may be used as a therapeutic strategy for vitiligo treatment.

Chronic temperature stress inhibits reproduction and disrupts endocytosis via chaperone titration in Caenorhabditis elegans

BackgroundTemperature influences biology at all levels, from altering rates of biochemical reactions to determining sustainability of entire ecosystems. Although extended exposure to elevated temperatures influences organismal phenotypes important for human health, agriculture, and ecology, the molecular mechanisms that drive these responses remain largely unexplored. Prolonged, mild temperature stress (48 h at 28 °C) has been shown to inhibit reproduction in Caenorhabditis elegans without significantly impacting motility or viability.ResultsAnalysis of molecular responses to chronic stress using RNA-seq uncovers dramatic effects on the transcriptome that are fundamentally distinct from the well-characterized, acute heat shock response (HSR). While a large portion of the genome is differentially expressed ≥ 4-fold after 48 h at 28 °C, the only major class of oogenesis-associated genes affected is the vitellogenin gene family that encodes for yolk proteins (YPs). Whereas YP mRNAs decrease, the proteins accumulate and mislocalize in the pseudocoelomic space as early as 6 h, well before reproduction declines. A trafficking defect in a second, unrelated fluorescent reporter and a decrease in pre-synaptic neuronal signaling indicate that the YP mislocalization is caused by a generalized defect in endocytosis. Molecular chaperones are involved in both endocytosis and refolding damaged proteins. Decreasing levels of the major HSP70 chaperone, HSP-1, causes similar YP trafficking defects in the absence of stress. Conversely, increasing chaperone levels through overexpression of the transcription factor HSF-1 rescues YP trafficking and restores neuronal signaling.ConclusionsThese data implicate chaperone titration during chronic stress as a molecular mechanism contributing to endocytic defects that influence multiple aspects of organismal physiology. Notably, HSF-1 overexpression improves recovery of viable offspring after exposure to stress. These findings provide important molecular insights into understanding organismal responses to temperature stress as well as phenotypes associated with chronic protein misfolding.

The Ubiquitin Gene Expression Pattern and Sensitivity to UBB and UBC Knockdown Differentiate Primary 23132/87 and Metastatic MKN45 Gastric Cancer Cells.

Gastric cancer (GC) is one of the most common and lethal cancers. Alterations in the ubiquitin (Ub) system play key roles in the carcinogenetic process and in metastasis development. Overexpression of transcription factors YY1, HSF1 and SP1, known to regulate Ub gene expression, is a predictor of poor prognosis and shorter survival in several cancers. In this study, we compared a primary (23132/87) and a metastatic (MKN45) GC cell line. We found a statistically significant higher expression of three out of four Ub coding genes, UBC, UBB and RPS27A, in MKN45 compared to 23132/87. However, while the total Ub protein content and the distribution of Ub between the conjugated and free pools were similar in these two GC cell lines, the proteasome activity was higher in MKN45. Ub gene expression was not affected upon YY1, HSF1 or SP1 small interfering RNA (siRNA) transfection, in both 23132/87 and MKN45 cell lines. Interestingly, the simultaneous knockdown of UBB and UBC mRNAs reduced the Ub content in both cell lines, but was more critical in the primary GC cell line 23132/87, causing a reduction in cell viability due to apoptosis induction and a decrease in the oncoprotein and metastatization marker β-catenin levels. Our results identify UBB and UBC as pro-survival genes in primary gastric adenocarcinoma 23132/87 cells.

Cloning and identification of grass carp transcription factor HSF1 and its characterization involving the production of fish HSP70.

In mammals, heat shock transcription factor 1 (HSF1) is well documented as the critical transcript factor to regulate heat shock protein 70 (HSP70) expression under different stresses, such as heat shock or bacterial infection. In fish, Hsf1 responses to physiological and environmental stresses and regulates Hsp70 expression under thermal exposure. However, the functional role of Hsf1 in Hsp70 production is still elusive under bacterial infection. In the present study, a coding sequence of grass carp hsf1 (gchsf1) gene was cloned and identified. Using Ctenopharyngodon idellus kidney (CIK) cells as the model, we found that lipopolysaccharide (LPS) exerted stimulatory effects on the expression of grass carp hsp70 (gchsp70) and hsf1, implying possible relationship of Hsp70 and Hsf1 under immune stimulation in fish. To validate the hypothesis, overexpression of gcHsf1 was performed in CIK cells, and the effects of overexpressing gcHsf1 on the expression of gcHsp70 in the absence or presence of LPS were examined. Results showed that LPS significantly upregulated the transcription and protein synthesis of gcHsp70, and these stimulatory effects were further amplified when overexpression of gcHsf1 was performed. Furthermore, luciferase reporter assays in CIK cells revealed that both overexpression of Hsf1 and LPS upregulated gchsp70 transcription, and their combined treatment further enhanced the gchsp70 promoter activity. Moreover, the regions responsive to these treatments were mapped to the promoter of gchsp70. Besides transcriptional level and cellular protein contents, gcHsp70 secretion was measured by competitive ELISA, uncovering that gcHsf1 enhanced the release of gcHsp70 induced by LPS in the same cells. These data not only demonstrated the enhancement of Hsf1 in Hsp70 production but also initially revealed the involvement of Hsf1-Hsp70 axis in mediating inflammatory response in fish.

721 Abnormal autophagosome formation increased melanocyte sensitivity to H2O2-induced oxidative stress in vitiligo

Autophagy is a controlled self-digestion process which can protect cells against oxidative damage. Dysregulated autophagy has been demonstrated to increase melanocyte sensitivity to oxidative stress in vitiligo. However, the exact mechanism is still not clear. This study aimed to determine the implications of autophagy for melanocyte survival in response to oxidative stress. Our results demonstrated that the autophagic flux in PIG1 exposure to H2O2 was significantly enhanced compared with that in PIG3V, which were accompanied by high level of ROS accumulation, membrane potential changes, and increased apoptosis. It indicates that vitiligo melanocytes exhibited hypersensitivity to H2O2-induced oxidative injury due to dysregulated autophagy. To further explore the mechanism, we performed RNA sequencing to compare the RNA expression in PIG1 and PIG3V cells exposed to H2O2, the bioinformatic analysis indicate that autophagosome formation was impaired in vitiligo melanocytes, our in vitro study also showed that inhibition of autolysosome degradation can not lead to autophagosome accumulation in vitiligo melanocytes, confirming that the impairment of autophagosome formation is responsible for the defects of autophagy in vitiligo melanocytes, the further study also showed that overexpression of HSF1, the main transcription factor for Atg5 and Atg12, could reduce H2O2-induced oxidative damage of vitiligo melanocytes. Our data demonstrated that owing to the deficiency of HSF1 expression, the autophagosome formation was blocked, which resulted in autophagy impairment and further increase the sensitivity of vitiligo melanocytes to oxidative stress. Our results indicating that targeting autophagy may be a potential therapy option.

HSF1 promotes the viability of islet β-cells via upregulating SIRPα expression.

Increasing evidence has shown that HSF1 is involved in glycemia regulation, and SIRPα plays a pivotal role in islet β-cell viability. However, it is still unknown whether SIRPα is associated with HSF1 in regulating the cell viability and cell death of islet β-cells. Western blot and qPCR were applied to determine protein and mRNA levels of HSF1 and SIRPα. Cell viability and death were investigated by cell counting kit-8 and trypan blue exclusion assay. Meanwhile, cell apoptosis was analyzed by detecting caspase3 activity. Moreover, luciferase reporter assay was applied to explore the mechanism by which HSF1 transcriptionally upregulated SIRPα expression. Our study reveals that HSF1 expression was lower in islets from T1DM compared to normal mice. We found that overexpression of HSF1 decreased the apoptosis of islet β-cell lines. Moreover, we demonstrated that overexpression of HSF1 decreased the apoptosis of islet β-cells through increasing the expression of SIRPα. In terms of mechanism, luciferase reporter assays showed that HSF1 upregulated SIRPα expression by activating its gene promoter region. The binding site (-1809 to -1795) was required for HSF1-induced increase of SIRPα gene promoter activity. These results indicate that the low expression of HSF1/SIRPα may be one of the mechanisms of islet β-cell death and targeting HSF1/SIRPα may be a novel strategy for the treatment of T1DM.

Transcription Factor YY1 Inhibits the Expression of THY1 to Promote Interstitial Pulmonary Fibrosis by Activating the HSF1/miR-214 Axis

Background: Pulmonary fibrosis is an inflammatory disease of pulmonary interstitium caused by many reasons. Recent studies have reported aberrant expression of microRNAs (miRNAs) in human embryonic pulmonary fibroblasts (HEPF), but their underlying mechanism remains to be further explored. In this study, we explored effect of YY1/HSF1/miR-214/THY1 axis on interstitial pulmonary fibrosis (IPF). Methods: IPF related microarray GSE24206 was downloaded from GEO database. Loss and gain of function tests were conducted to identify roles of YY1, HSF1, miR-214 and THY1 in IPF. The related expression of related indexes in tissues or cells was measured by qRT-PCR or western blot assay. Cell survival rate was detected by CCK8. Binding relationship between miR-214 and THY1 was verified using dual-luciferase reporter assay. Subsequently, IPF model in mice was induced by bleomycin. And the pathological changes of the lung tissues were assessed by HE and Masson staining, while the amount of collagen in the lung tissues of mice was measured by hydroxyproline assay. Results: In HEPF, YY1 promoted HSF1 and miR-214 expression, while miR-214 could promote the transformation HEPF by downregulating THY1. Silencing YY1 or HSF1 could inhibit the proliferation of HEPF and the expression of Ki67 and biomarkers of fibrosis, while overexpression of HSF1 or miR-214 could reverse this effect. Conclusion: Our study demonstrated the facilitating role of YY1/HSF1/miR-214/THY1 axis in the transformation of IPF. Funding Statement: The authors stated: None. Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: Animals were treated humanely using approved procedures in compliance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. The protocol was approved by the Institutional Animal Care and Use Committee of Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China.

HSB-1 Inhibition and HSF-1 Overexpression Trigger Overlapping Transcriptional Changes To Promote Longevity in Caenorhabditis elegans.

Heat shock factor 1 (HSF-1) is a component of the heat shock response pathway that is induced by cytoplasmic proteotoxic stress. In addition to its role in stress response, HSF-1 also acts as a key regulator of the rate of organismal aging. Overexpression of HSF-1 promotes longevity in C. elegans via mechanisms that remain less understood. Moreover, genetic ablation of a negative regulator of HSF-1, termed as heat shock factor binding protein 1 (HSB-1), results in hsf-1-dependent life span extension in animals. Here we show that in the absence of HSB-1, HSF-1 acquires increased DNA binding activity to its genomic target sequence. Using RNA-Seq to compare the gene expression profiles of the hsb-1 mutant and hsf-1 overexpression strains, we found that while more than 1,500 transcripts show ≥1.5-fold upregulation due to HSF-1 overexpression, HSB-1 inhibition alters the expression of less than 500 genes in C. elegans. Roughly half of the differentially regulated transcripts in the hsb-1 mutant have altered expression also in hsf-1 overexpressing animals, with a strongly correlated fold-expression pattern between the two strains. In addition, genes that are upregulated via both HSB-1 inhibition and HSF-1 overexpression include numerous DAF-16 targets that have known functions in longevity regulation. This study identifies how HSB-1 acts as a specific regulator of the transactivation potential of HSF-1 in non-stressed conditions, thus providing a detailed understanding of the role of HSB-1/HSF-1 signaling pathway in transcriptional regulation and longevity in C. elegans.

Salvianolic Acid A Attenuates Endoplasmic Reticulum Stress and Protects Against Cholestasis-Induced Liver Fibrosis via the SIRT1/HSF1 Pathway.

Background: Endoplasmic reticulum stress (ER stress) plays a critical role in the pathogenesis of liver fibrosis; thus, it can be a potential therapeutic target of fibrosis. However, the mechanism of ER stress regulation in fibrosis, particularly through sirtuin 1 (SIRT1), remains unclear. The objective of this study was to investigate the effect of SIRT1-mediated inhibition of ER stress in bile duct ligation (BDL)-induced liver fibrosis, and to explore the effect of salvianolic acid A (SalA) on BDL-induced liver fibrosis through SIRT1/heat shock factor 1 (HSF1) signaling.Materials and Methods: We explored the effects of SalA on liver fibrosis and ER stress in BDL-induced liver fibrosis in rats and the human hepatic stellate cell line LX2 cells. The LX2 cells were treated with 20 ng of platelet-derived growth factor-BB homodimer (PDGF-BB) for 24 h, and then incubated in the absence or presence of SalA (25 μM) for 24 h.Results: In vivo, SalA treatment alleviated BDL-induced liver injury and ER stress. Importantly, SalA treatment increased HSF1 expression and activity using a SIRT1-dependent mechanism. In LX2 cells, PDGF-BB induced ER stress and fibrosis were blocked by HSF1 overexpression. Furthermore, SIRT1 siRNA abrogated the SalA-mediated promotion of HSF1 deacetylation and expression, suggesting that SalA-mediated protection occurs by SIRT1 targeting HSF1 for deacetylation.Conclusion: This is the first study to identify the SIRT1/HSF1 pathway as a key therapeutic target for controlling BDL-induced liver fibrosis and to show that SalA confers protection against BDL- and PDGF-BB-induced hepatic fibrosis and ER stress through SIRT1-mediated HSF1 deacetylation.