HSF1 at a glance

Searching for LINCS to Stress: Using Text Mining to Automate Reference Chemical Curation

Adaptive stress response pathways (SRPs) restore cellular homeostasis following perturbation but may activate terminal outcomes like apoptosis, autophagy, or cellular senescence if disruption exceeds critical thresholds. Because SRPs hold the key to vital cellular tipping points, they are targeted for therapeutic interventions and assessed as biomarkers of toxicity. Hence, we are developing a public database of chemicals that perturb SRPs to enable new data-driven tools to improve public health. Here, we report on the automated text-mining pipeline we used to build and curate the first version of this database. We started with 100 reference SRP chemicals gathered from published biomarker studies to bootstrap the database. Second, we used information retrieval to find co-occurrences of reference chemicals with SRP terms in PubMed abstracts and determined pairwise mutual information thresholds to filter biologically relevant relationships. Third, we applied these thresholds to find 1206 putative SRP perturbagens within thousands of substances in the Library of Integrated Network-Based Cellular Signatures (LINCS). To assign SRP activity to LINCS chemicals, domain experts had to manually review at least three publications for each of 1206 chemicals out of 181,805 total abstracts. To accomplish this efficiently, we implemented a machine learning approach to predict SRP classifications from texts to prioritize abstracts. In 5-fold cross-validation testing with a corpus derived from the 100 reference chemicals, artificial neural networks performed the best (F1-macro = 0.678) and prioritized 2479/181,805 abstracts for expert review, which resulted in 457 chemicals annotated with SRP activities. An independent analysis of enriched mechanisms of action and chemical use class supported the text-mined chemical associations (p < 0.05): heat shock inducers were linked with HSP90 and DNA damage inducers to topoisomerase inhibition. This database will enable novel applications of LINCS data to evaluate SRP activities and to further develop tools for biomedical information extraction from the literature.

Osteogenesis imperfecta type 10 and the cellular scaffolds underlying common immunological diseases

Osteogenesis imperfecta type 10 (OI10) is caused by loss of function codon variants in the gene SERPINH1 that encodes heat shock protein 47 (HSP47), rather than in a gene specifying bone formation. The HSP47 variants disrupt the folding of both collagen and the endonuclease IRE1α (inositol-requiring enzyme 1α) that splices X-Box Binding Protein 1 (XBP1) mRNA. Besides impairing bone development, variants likely affect osteoclast differentiation. Three distinct biochemical scaffold play key roles in the differentiation and regulated cell death of osteoclasts. These scaffolds consist of non-templated protein modifications, ordered lipid arrays, and protein filaments. The scaffold components are specified genetically, but assemble in response to extracellular perturbagens, pathogens, and left-handed Z-RNA helices encoded genomically by flipons. The outcomes depend on interactions between RIPK1, RIPK3, TRIF, and ZBP1 through short interaction motifs called RHIMs. The causal HSP47 nonsynonymous substitutions occur in a novel variant leucine repeat region (vLRR) that are distantly related to RHIMs. Other vLRR protein variants are causal for a variety of different mendelian diseases. The same scaffolds that drive mendelian pathology are associated with many other complex disease outcomes. Their assembly is triggered dynamically by flipons and other context-specific switches rather than by causal, mendelian, codon variants.

pH Dependence of HSF1 trimerization is shaped by intramolecular interactions

Heat shock factor 1 (HSF1) primarily regulates various cellular stress responses. Previous studies have shown that low pH within the physiological range directly activates HSF1 function in vitro. However, the detailed molecular mechanisms remain unclear. This study proposes a molecular mechanism based on the trimerization behavior of HSF1 at different pH values. Extensive mutagenesis of human and goldfish HSF1 revealed that the optimal pH for trimerization depended on the identity of residue 103. In particular, when residue 103 was occupied by tyrosine, a significant increase in the optimal pH was observed, regardless of the rest of the sequence. This behavior can be explained by the protonation state of the neighboring histidine residues, His101 and His110. Residue 103 plays a key role in trimerization by forming disulfide or non-covalent bonds with Cys36. If tyrosine resides at residue 103 in an acidic environment, its electrostatic interactions with positively charged histidine residues prevent effective trimerization. His101 and His110 are neutralized at a higher pH, which releases Tyr103 to interact with Cys36 and drives the effective trimerization of HSF1. This study showed that the protonation state of a histidine residue can regulate the intramolecular interactions, which consequently leads to a drastic change in the oligomerization behavior of the entire protein.

Intermolecular Interactions between Cysteine and Aromatic Amino Acids with a Phenyl Moiety in the DNA-Binding Domain of Heat Shock Factor 1 Regulate Thermal Stress-Induced Trimerization

In this study, we investigated the trimerization mechanism and structure of heat shock factor 1 (HSF1) using western blotting, tryptophan (Trp) fluorescence spectroscopy, and molecular modeling. First, we examined the DNA-binding domains of human (Homo sapiens), goldfish (Carassius auratus), and walleye pollock (Gadus chalcogrammus) HSF1s by mutating key residues (36 and 103) that are thought to directly affect trimer formation. Human, goldfish, and walleye pollock HSF1s contain cysteine at residue 36 but cysteine (C), tyrosine (Y), and phenylalanine (F), respectively, at residue 103. The optimal trimerization temperatures for the wild-type HSF1s of each species were found to be 42, 37, and 20 °C, respectively. Interestingly, a mutation experiment revealed that trimerization occurred at 42 °C when residue 103 was cysteine, at 37 °C when it was tyrosine, and at 20 °C when it was phenylalanine, regardless of the species. In addition, it was confirmed that when residue 103 of the three species was mutated to alanine, trimerization did not occur. This suggests that in addition to trimerization via disulfide bond formation between the cysteine residues in human HSF1, trimerization can also occur via the formation of a different type of bond between cysteine and aromatic ring residues such as tyrosine and phenylalanine. We also confirmed that at least one cysteine is required for the trimerization of HSF1s, regardless of its position (residue 36 or 103). Additionally, it was shown that the trimer formation temperature is related to growth and survival in fish.

Proteostasis in neurodegenerative diseases

Proteostasis is essential for normal function of proteins and vital for cellular health and survival. Proteostasis encompasses all stages in the "life" of a protein, that is, from translation to functional performance and, ultimately, to degradation. Proteins need native conformations for function and in the presence of multiple types of stress, their misfolding and aggregation can occur. A coordinated network of proteins is at the core of proteostasis in cells. Among these, chaperones are required for maintaining the integrity of protein conformations by preventing misfolding and aggregation and guide those with abnormal conformation to degradation. The ubiquitin-proteasome system (UPS) and autophagy are major cellular pathways for degrading proteins. Although failure or decreased functioning of components of this network can lead to proteotoxicity and disease, like neuron degenerative diseases, underlying factors are not completely understood. Accumulating misfolded and aggregated proteins are considered major pathomechanisms of neurodegeneration. In this chapter, we have described the components of three major branches required for proteostasis-chaperones, UPS and autophagy, the mechanistic basis of their function, and their potential for protection against various neurodegenerative conditions, like Alzheimer's, Parkinson's, and Huntington's disease. The modulation of various proteostasis network proteins, like chaperones, E3 ubiquitin ligases, proteasome, and autophagy-associated proteins as therapeutic targets by small molecules as well as new and unconventional approaches, shows promise.

Expression and localization of apelin and apelin receptor protein in the oviduct of letrozole-induced hyperandrogenized mice

Apelin and its receptor (APJ) are expressed in the reproductive organs of some mammalian females. The function of oviduct has also been suggested to be compromised in the hyperandrogenism condition. However, expression of apelin and APJ has not been shown in the oviduct of hyperandrogenized mice. Thus, the present study has investigated the localization and expression of apelin and APJ in the letrozole-induced hyperandrogenized mice oviduct. Histomorphometric analysis showed decreased lumen of oviduct in the hyperandrogenized mice. Our results showed elevated expression of APJ and decreased abundance of apelin in the hyperandrogenized mice oviduct. This finding suggests impaired apelin signaling in the oviduct of hyperandrogenized mice. The expression of androgen receptor was upregulated while estrogen receptors were downregulated in the hyperandrogenized mice. The expression of HSP70 was also downregulated along with increased expression of active caspase 3 and BAX and decreased expression of BCL2 in hyperandrogenized mice. Furthermore, the phosphorylation of phospho-Ser473-Akt and phospho-Thr308-Akt also showed differential levels in the oviduct of hyperandrogenized mice. Whether this differential phosphorylation of Akt was solely due to impaired apelin signaling in the oviduct, remains unclear. Moreover, increased androgen signaling and suppressed estrogen signaling coincides with elevated apoptosis. In conclusion, hyperandrogenized conditions could also impair the gamete transport and fertilization process due to apoptosis in the oviduct. However, further study would be required to unravel the exact role of apelin signaling in the oviduct in relation to apoptosis.

Heat shock proteins as a key defense mechanism in poultry production under heat stress conditions

Over the past years, the poultry industry has been assigned to greater production performance but has become highly sensitive to environmental changes. The average world temperature has recently risen and is predicted to continue rising. In open-sided houses, poultry species confront high outside temperatures, which cause heat stress (HS) problems. Cellular responses are vital in poultry, as they may lead to identifying confirmed HS biomarkers. Heat shock proteins (HSP) are highly preserved protein families that play a significant role in cell function and cytoprotection against various stressors, including HS. The optimal response in which the cell survives the HS elevates HSP levels that prevent cellular proteins from damage caused by HS. The HSP have chaperonic action to ensure that stress-denatured proteins are folded, unfolded, and refolded. The HSP70 and HSP90 are the primary HSP in poultry with a defensive function during HS. HSP70 was the optimal biological marker for assessing HS among the HSP studied. The current review attempts to ascertain the value of HSP as a heat stress defense mechanism in poultry.

Targeting the heat shock response induced by modulated electro-hyperthermia (mEHT) in cancer

The Heat Shock Response (HSR) is a cellular stress reaction crucial for cell survival against stressors, including heat, in both healthy and cancer cells. Modulated electro-hyperthermia (mEHT) is an emerging non-invasive cancer therapy utilizing electromagnetic fields to selectively target cancer cells via temperature-dependent and independent mechanisms. However, mEHT triggers HSR in treated cells. Despite demonstrated efficacy in cancer treatment, understanding the underlying molecular mechanisms for improved therapeutic outcomes remains a focus. This review examines the HSR induced by mEHT in cancer cells, discussing potential strategies to modulate it for enhanced tumor-killing effects. Approaches such as HSF1 gene-knockdown and small molecule inhibitors like KRIBB11 are explored to downregulate the HSR and augment tumor destruction. We emphasize the impact of HSR inhibition on cancer cell viability, mEHT sensitivity, and potential synergistic effects, addressing challenges and future directions. This understanding offers opportunities for optimizing treatment strategies and advancing precision medicine in cancer therapy.

Deletion of the transcription factors Hsf1, Msn2 and Msn4 in yeast uncovers transcriptional reprogramming in response to proteotoxic stress

The response to proteotoxic stresses such as heat shock allows organisms to maintain protein homeostasis under changing environmental conditions. We asked what happens if an organism can no longer react to cytosolic proteotoxic stress. To test this, we deleted or depleted, either individually or in combination, the stress-responsive transcription factors Msn2, Msn4, and Hsf1 in Saccharomyces cerevisiae. Our study reveals a combination of survival strategies, which together protect essential proteins. Msn2 and 4 broadly reprogram transcription, triggering the response to oxidative stress, as well as biosynthesis of the protective sugar trehalose and glycolytic enzymes, while Hsf1 mainly induces the synthesis of molecular chaperones and reverses the transcriptional response upon prolonged mild heat stress (adaptation).

The dance of proteostasis and metabolism: Unveiling the caloristatic controlling switch

The heat shock response (HSR) is an ancient and evolutionarily conserved mechanism designed to restore cellular homeostasis following proteotoxic challenges. However, it has become increasingly evident that disruptions in energy metabolism also trigger the HSR. This interplay between proteostasis and energy regulation is rooted in the fundamental need for ATP to fuel protein synthesis and repair, making the HSR an essential component of cellular energy management. Recent findings suggest that the origins of proteostasis-defending systems can be traced back over 3.6 billion years, aligning with the emergence of sugar kinases that optimized glycolysis around 3.594 billion years ago. This evolutionary connection is underscored by the spatial similarities between the nucleotide-binding domain of HSP70, the key player in protein chaperone machinery, and hexokinases. The HSR serves as a hub that integrates energy metabolism and resolution of inflammation, further highlighting its role in maintaining cellular homeostasis. Notably, 5'-adenosine monophosphate-activated protein kinase emerges as a central regulator, promoting the HSR during predominantly proteotoxic stress while suppressing it in response to predominantly metabolic stress. The complex relationship between 5'-adenosine monophosphate-activated protein kinase and the HSR is finely tuned, with paradoxical effects observed under different stress conditions. This delicate equilibrium, known as caloristasis, ensures that cellular homeostasis is maintained despite shifting environmental and intracellular conditions. Understanding the caloristatic controlling switch at the heart of this interplay is crucial. It offers insights into a wide range of conditions, including glycemic control, obesity, type 2 diabetes, cardiovascular and neurodegenerative diseases, reproductive abnormalities, and the optimization of exercise routines. These findings highlight the profound interconnectedness of proteostasis and energy metabolism in cellular function and adaptation.

Resolution of inflammation in chronic disease via restoration of the heat shock response (HSR)

Effective resolution of inflammation via the heat shock response (HSR) is pivotal in averting the transition to chronic inflammatory states. This transition characterizes a spectrum of debilitating conditions, including insulin resistance, obesity, type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular ailments. This manuscript explores a range of physiological, pharmacological, and nutraceutical interventions aimed at reinstating the HSR in the context of chronic low-grade inflammation, as well as protocols to assess the HSR. Monitoring the progression or suppression of the HSR in patients and laboratory animals offers predictive insights into the organism's capacity to combat chronic inflammation, as well as the impact of exercise and hyperthermic treatments (e.g., sauna or hot tub baths) on the HSR. Interestingly, a reciprocal correlation exists between the expression of HSR components in peripheral blood leukocytes (PBL) and the extent of local tissue proinflammatory activity in individuals afflicted by chronic inflammatory disorders. Therefore, the Heck index, contrasting extracellular 70 kDa family of heat shock proteins (HSP70) (proinflammatory) and intracellular HSP70 (anti-inflammatory) in PBL, serves as a valuable metric for HSR assessment. Our laboratory has also developed straightforward protocols for evaluating HSR by subjecting whole blood samples from both rodents and human volunteers to ex vivo heat challenges. Collectively, this discussion underscores the critical role of HSR disruption in the pathogenesis of chronic inflammatory states and emphasizes the significance of simple, cost-effective tools for clinical HSR assessment. This understanding is instrumental in the development of innovative strategies for preventing and managing chronic inflammatory diseases, which continue to exert a substantial global burden on morbidity and mortality.

Heat Shock Protein 90 in Parkinson's Disease: Profile of a Serial Killer

Parkinson's disease (PD) is the second most common neurodegenerative disease, characterized by abnormal α-synuclein misfolding and aggregation, mitochondrial dysfunction, oxidative stress, as well as progressive death of dopaminergic neurons in the substantia nigra. Molecular chaperones play a role in stabilizing proteins and helping them achieve their proper structure. Previous studies have shown that overexpression of heat shock protein 90 (HSP90) can lead to the death of dopaminergic neurons associated with PD. Inhibiting HSP90 is considered a potential treatment approach for neurodegenerative disorders, as it may reduce protein aggregation and related toxicity, as well as suppress various forms of regulated cell death (RCD). This review provides an overview of HSP90 and its role in PD, focusing on its modulation of proteostasis and quality control of LRRK2. The review also explores the effects of HSP90 on different types of RCD, such as apoptosis, chaperone-mediated autophagy (CMA), necroptosis, and ferroptosis. Additionally, it discusses HSP90 inhibitors that have been tested in PD models. We will highlight the under-investigated neuroprotective effects of HSP90 inhibition, including modulation of oxidative stress, mitochondrial dysfunction, PINK/PARKIN, heat shock factor 1 (HSF1), histone deacetylase 6 (HDAC6), and the PHD2-HSP90 complex-mediated mitochondrial stress pathway. By examining previous literature, this review uncovers overlooked neuroprotective mechanisms and emphasizes the need for further research on HSP90 inhibitors as potential therapeutic strategies for PD. Finally, the review discusses the potential limitations and possibilities of using HSP90 inhibitors in PD therapy.

MUC1 promotes lymph node metastasis in esophageal squamous cell carcinoma by downregulating DNAJB6 expression

BACKGROUND

Aberrant expression of MUC1 correlates with the progression of esophageal squamous cell carcinoma (ESCC), this study aimed to explore the effect of targeting MUC1 by Go-203 on malignant behavior of ESCC and the underlying mechanism.

METHODS AND RESULTS

IHC was used to examine the expression of MUC1 and DNAJB6 in ESCC samples. qRT-PCR and western blotting were used to examine the expression of MUC1 and DNAJB6 in ESCC cell lines. CCK8, wound healing, and transwell assays were used to determine the effect of regulating MUC1/DNAJB6 on the proliferation, migration, and invasion of ESCC cells. The effect of overexpressing/targeting MUC1 on the activation of the AKT/HSF-1 pathway was determined by western blotting. A negative correlation was confirmed between the expression of DNAJB6 and MUC1 in ESCC tissue samples by IHC, and high expression of MUC1 and low expression of DNAJB6 correlated with lymph node metastasis in ESCC patients. Overexpressing MUC1 downregulated the expression of DNAJB6, promoted ESCC proliferation, invasion, migration and activated the AKT pathway, while targeting MUC1 suppressed proliferation, invasion, migration, and the AKT pathway and up-regulated DNAJB6 expression in vitro. Moreover, MUC1 increased the phosphorylation of HSF-1 via the AKT pathway, and inhibiting AKT-HSF-1 increased the expression of DNAJB6 in vitro.

CONCLUSIONS

This study indicated that MUC1 could promote tumorigenesis and metastasis in ESCC by downregulating DNAJB6 expression through AKT-HSF-1 pathway.

ERK2-topoisomerase II regulatory axis is important for gene activation in immediate early genes

The function of the mitogen-activated protein kinase signaling pathway is required for the activation of immediate early genes (IEGs), including EGR1 and FOS, for cell growth and proliferation. Recent studies have identified topoisomerase II (TOP2) as one of the important regulators of the transcriptional activation of IEGs. However, the mechanism underlying transcriptional regulation involving TOP2 in IEG activation has remained unknown. Here, we demonstrate that ERK2, but not ERK1, is important for IEG transcriptional activation and report a critical ELK1 binding sequence for ERK2 function at the EGR1 gene. Our data indicate that both ERK1 and ERK2 extensively phosphorylate the C-terminal domain of TOP2B at mutual and distinctive residues. Although both ERK1 and ERK2 enhance the catalytic rate of TOP2B required to relax positive DNA supercoiling, ERK2 delays TOP2B catalysis of negative DNA supercoiling. In addition, ERK1 may relax DNA supercoiling by itself. ERK2 catalytic inhibition or knock-down interferes with transcription and deregulates TOP2B in IEGs. Furthermore, we present the first cryo-EM structure of the human cell-purified TOP2B and etoposide together with the EGR1 transcriptional start site (-30 to +20) that has the strongest affinity to TOP2B within -423 to +332. The structure shows TOP2B-mediated breakage and dramatic bending of the DNA. Transcription is activated by etoposide, while it is inhibited by ICRF193 at EGR1 and FOS, suggesting that TOP2B-mediated DNA break to favor transcriptional activation. Taken together, this study suggests that activated ERK2 phosphorylates TOP2B to regulate TOP2-DNA interactions and favor transcriptional activation in IEGs. We propose that TOP2B association, catalysis, and dissociation on its substrate DNA are important processes for regulating transcription and that ERK2-mediated TOP2B phosphorylation may be key for the catalysis and dissociation steps.

Hsf1 and the molecular chaperone Hsp90 support a 'rewiring stress response' leading to an adaptive cell size increase in chronic stress

Cells are exposed to a wide variety of internal and external stresses. Although many studies have focused on cellular responses to acute and severe stresses, little is known about how cellular systems adapt to sublethal chronic stresses. Using mammalian cells in culture, we discovered that they adapt to chronic mild stresses of up to two weeks, notably proteotoxic stresses such as heat, by increasing their size and translation, thereby scaling the amount of total protein. These adaptations render them more resilient to persistent and subsequent stresses. We demonstrate that Hsf1, well known for its role in acute stress responses, is required for the cell size increase, and that the molecular chaperone Hsp90 is essential for coupling the cell size increase to augmented translation. We term this translational reprogramming the 'rewiring stress response', and propose that this protective process of chronic stress adaptation contributes to the increase in size as cells get older, and that its failure promotes aging.

Heat stress adaptation in cows - Physiological responses and underlying molecular mechanisms

Heat stress is a key abiotic stressor for dairy production in the tropics which is further compounded by the ongoing climate change. Heat stress not only adversely impacts the production and welfare of dairy cows but severely impacts the economics of dairying due to production losses and increased cost of rearing. Over the years, selection has ensured development of high producing breeds, however, the thermotolerance ability of animals has been largely overlooked. In the past decade, the ill effects of climate change have made it pertinent to rethink the selection strategies to opt for climate resilient breeds, to ensure optimum production and reproduction. This has led to renewed interest in evaluation of the impacts of heat stress on cows and the underlying mechanisms that results in their acclimatization and adaptation to varied thermal ambience. The understanding of heat stress and associated responses at various level of animal is crucial to device amelioration strategies to secure optimum production and welfare of cows. With this review, an effort has been made to provide an overview on temperature humidity index as an important indicator of heat stress, general effect of heat stress in dairy cows, and impact of heat stress and subsequent response at physiological, haematological, molecular and genetic level of dairy cows.

Transcriptional responses of cancer cells to heat shock-inducing stimuli involve amplification of robust HSF1 binding

Responses of cells to stimuli are increasingly discovered to involve the binding of sequence-specific transcription factors outside of known target genes. We wanted to determine to what extent the genome-wide binding and function of a transcription factor are shaped by the cell type versus the stimulus. To do so, we induced the Heat Shock Response pathway in two different cancer cell lines with two different stimuli and related the binding of its master regulator HSF1 to nascent RNA and chromatin accessibility. Here, we show that HSF1 binding patterns retain their identity between basal conditions and under different magnitudes of activation, so that common HSF1 binding is globally associated with distinct transcription outcomes. HSF1-induced increase in DNA accessibility was modest in scale, but occurred predominantly at remote genomic sites. Apart from regulating transcription at existing elements including promoters and enhancers, HSF1 binding amplified during responses to stimuli may engage inactive chromatin.

PRO-IP-seq tracks molecular modifications of engaged Pol II complexes at nucleotide resolution

RNA Polymerase II (Pol II) is a multi-subunit complex that undergoes covalent modifications as transcription proceeds through genes and enhancers. Rate-limiting steps of transcription control Pol II recruitment, site and degree of initiation, pausing duration, productive elongation, nascent transcript processing, transcription termination, and Pol II recycling. Here, we develop Precision Run-On coupled to Immuno-Precipitation sequencing (PRO-IP-seq), which double-selects nascent RNAs and transcription complexes, and track phosphorylation of Pol II C-terminal domain (CTD) at nucleotide-resolution. We uncover precise positional control of Pol II CTD phosphorylation as transcription proceeds from the initiating nucleotide (+1 nt), through early (+18 to +30 nt) and late (+31 to +60 nt) promoter-proximal pause, and into productive elongation. Pol II CTD is predominantly unphosphorylated from initiation until the early pause-region, whereas serine-2- and serine-5-phosphorylations are preferentially deposited in the later pause-region. Upon pause-release, serine-7-phosphorylation rapidly increases and dominates over the region where Pol II assembles elongation factors and accelerates to its full elongational speed. Interestingly, tracking CTD modifications upon heat-induced transcriptional reprogramming demonstrates that Pol II with phosphorylated CTD remains paused on thousands of heat-repressed genes. These results uncover dynamic Pol II regulation at rate-limiting steps of transcription and provide a nucleotide-resolution technique for tracking composition of engaged transcription complexes.

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.

HSF1 protects cells from cadmium toxicity by governing proteome integrity

BACKGROUND

Cadmium toxicity has been associated with disruption of protein homeostasis by interfering with protein folding processes. Heat shock factor 1 (HSF1) coordinates the rapid and extensive cellular response to maintain proteomic balance facing the challenges from many environmental stressors. Thus, we suspect that HSF1 may shield cells from cadmium toxicity by conserving proteome integrity.

RESULTS

Here, we demonstrate that cadmium, a highly poisonous metal, induces aggregation of cytosolic proteins in human cells, which disrupts protein homeostasis and activates HSF1. Cadmium exposure increases HSF1's phosphorylation, nuclear translocation and DNA bindings. Aside from this, HSF1 goes through liquid-liquid phase separation to form small nuclear condensates upon cadmium exposure. A specific regulatory domain of HSF1 is critical for HSF1's phase separation capability. Most importantly, human cells with impaired HSF1 are sensitized to cadmium, however, cells with overexpressed HSF1 are protected from cadmium toxicity. Overexpression of HSF1 in human cells reduces protein aggregates, amyloid fibrils and DNA damages to antagonize cadmium toxicity.

CONCLUSIONS

HSF1 protects cells from cadmium toxicity by governing the integrity of both proteome and genome. Similar mechanisms may enable HSF1 to alleviate cellular toxicity caused by other heavy metals. HSF1's role in cadmium exposure may provide important insights into the toxic effects of heavy metals on human cells and body organs, allowing us to better manage heavy metal poisoning.

The tumour-promoting role of protein homeostasis: Implications for cancer immunotherapy

Protein homeostasis, an important aspect of cellular fitness that encompasses the balance of production, folding and degradation of proteins, has been linked to several diseases of the human body. Multiple interconnected pathways coordinate to maintain protein homeostasis within the cell. Recently, the role of the protein homeostasis network in tumorigenesis and tumour progression has gradually come to light. Here, we summarize the involvement of the most prominent components of the protein quality control mechanisms (HSR, UPS, autophagy, UPR and ERAD) in tumour development and cancer immunity. In addition, evidence for protein quality control mechanisms and targeted drugs is outlined, and attempts to combine these drugs with cancer immunotherapy are discussed. Altogether, combination therapy represents a promising direction for future investigations, and this exciting insight will be further illuminated by the development of drugs that can reach a balance between the benefits and hazards associated with protein homeostasis interference.

Epigenetic mechanisms of lncRNA in response to thermal stress during embryogenesis of allotetraploid Cyprinus carpio

Embryogenesis and epigenetic mechanisms of lncRNA may play an important role in the formation of temperature tolerance in allotetraploid Cyprinus carpio. To investigate the response of lncRNA to thermal stress during embryogenesis of C. carpio, transcriptome sequencing was performed on 81 embryo or larva samples from different early development stages and temperatures. We identified 45,097 lncRNAs and analyzed transcriptome variation during embryogenesis. Stage-specific and temperature-specific DE lncRNAs and DEGs were screened. GO and KEGG analysis identified numerous pathways involved in thermal stress. Temperature-specific regulation of cis-/trans-/antisense lncRNAs was analyzed. Interaction network analysis identified 6 hub lncRNAs and many hub genes, such as cdk1 and hsf1. Decreased expression of many essential genes regulated by lncRNAs may lead to the death of embryos at 33 °C. Our findings provide new insights into the regulation of lncRNA in thermal stress response during embryogenesis and contribute to the understanding of environmental adaptation of allotetraploid species.

Proteotoxic stress response in atherosclerotic cardiovascular disease: Emerging role of heat shock factor 1

Atherosclerosis is a major risk factor for cardiovascular diseases. Hypercholesterolemia has been both clinically and experimentally linked to cardiovascular disease and is involved in the initiation of atherosclerosis. Heat shock factor 1 (HSF1) is involved in the control of atherosclerosis. HSF1 is a critical transcriptional factor of the proteotoxic stress response that regulates the production of heat shock proteins (HSPs) and other important activities such as lipid metabolism. Recently, HSF1 is reported to directly interact with and inhibit AMP-activated protein kinase (AMPK) to promote lipogenesis and cholesterol synthesis. This review highlights roles of HSF1 and HSPs in critical metabolic pathways of atherosclerosis, including lipogenesis and proteome homeostasis.

Regulation of germline proteostasis by HSF1 and insulin/IGF-1 signaling

Protein homeostasis (proteostasis) is essential for cellular function and organismal health and requires the concerted actions of protein synthesis, folding, transport, and turnover. In sexually reproducing organisms, the immortal germline lineage passes genetic information across generations. Accumulating evidence indicates the importance of proteome integrity for germ cells as genome stability. As gametogenesis involves very active protein synthesis and is highly energy-demanding, it has unique requirements for proteostasis regulation and is sensitive to stress and nutrient availability. The heat shock factor 1 (HSF1), a key transcriptional regulator of cellular response to cytosolic and nuclear protein misfolding has evolutionarily conserved roles in germline development. Similarly, insulin/insulin-like growth factor-1 (IGF-1) signaling, a major nutrient-sensing pathway, impacts many aspects of gametogenesis. Here, we focus on HSF1 and IIS to review insights into their roles in germline proteostasis and discuss the implications on gamete quality control during stress and aging.

Revealing the potential regulatory relationship between HSP70, HSP90 and HSF genes under temperature stress

Heat Shock Protein (HSPs) gene family members play fundamental roles in different environmental stress tolerances, protect the structure and function of cells, and perform a significant task in cellular homeostasis. In this study, we conducted a genome-wide identification, evolutionary relationship analysis and gene expression analysis of the HSP70, HSP90, and HSF gene families in Ruditapes philippinarum. We identified 83 RpHSP70, 6 RpHSP90, and 3 RpHSF genes in R. philippinarum. The structural characteristics, chromosomal localization, and the gene structure map were constructed to reveal the characteristics of protein structures. Furthermore, the expression profiling of transcriptome data showed the expression pattern of HSP70, HSP90 and HSF genes in Manila clam from different populations, and under high and low temperature stress. In addition, we performed protein-protein interaction network analysis between HSP70, HSP90, and HSF gene family which enabled us to recognize the regulatory relationship between the two HSP gene families and the HSF gene family. Furthermore, the predicted sub-cellular location revealed a diversified subcellular distribution of HSP70, HSP90, and HSF proteins, which may be directly or indirectly associated with functional diversification under heat stress condition.

HSF1 Attenuates the Release of Inflammatory Cytokines Induced by Lipopolysaccharide through Transcriptional Regulation of Atg10

Autophagy plays an important role in endotoxemic mice, and heat shock factor 1 (HSF1) plays a crucial protective role in endotoxemic mice. However, the protective mechanisms of HSF1 are poorly understood. In this text, bioinformatics analysis, chromatin immunoprecipitation, and electrophoresis mobility shift assay were employed to investigate the underlying mechanisms. The results showed that the release of inflammatory cytokines increased and autophagy decreased significantly in Hsf1^-/- endotoxemic mice compared with those in Hsf1^+/+ endotoxemic mice. HSF1 could directly bind to the noncoding promoter region of the autophagy-related gene 10 (Atg10). The expression of ATG10 and the ratio of LC3-II/LC3-I were obviously decreased in LPS-treated Hsf1^-/- peritoneal macrophages (PM) versus those in LPS-treated Hsf1^+/+ PM. Overexpression of HSF1 increased the level of the ATG10 protein and enhanced the ratio of LC3-II/LC3-I in RAW264.7 cells. In contrast, silencing of HSF1 decreased the expression of ATG10 and markedly lowered the ratio of LC3-II/LC3-I. In a cotransfected cell experiment, the upregulation of autophagy by overexpression HSF1 was reversed by small interfering RNA (siRNA)-ATG10. Compared with the overexpression HSF1, the release of inflammatory cytokines induced by lipopolysaccharide (LPS) was decreased in pcDNA3.1-HSF1 with siRNA-ATG10 cotransfected RAW264.7 cells. On the other hand, the decrease of autophagy by siRNA-HSF1 was compensated by overexpression of ATG10. Compared with siRNA-HSF1, the release of inflammatory cytokines induced by LPS was increased in siRNA-HSF1 with pcDNA3.1-ATG10 cotransfected RAW264.7 cells. These results presented a novel mechanism that HSF1 attenuated the release of inflammatory cytokines induced by LPS through transcriptional regulation of Atg10. Targeting of HSF1-Atg10-autophagy might be an attractive strategy in endotoxemia therapeutics. IMPORTANCE HSF1 plays an important protective role in endotoxemic mice. However, the protective mechanisms of HSF1 are poorly understood. In the present study, we demonstrated that HSF1 upregulated ATG10 through specifically binding Atg10 promoter's noncoding region in LPS-treated PM and RAW264.7 cells. By depletion of HSF1, the expression of ATG10 was significantly decreased, leading to aggravate releasing of inflammatory cytokines in LPS-treated RAW264.7 cells. These findings provided a new mechanism of HSF1 in endotoxemic mice.

Pharmacologic Targeting of the C-Terminus of Heat Shock Protein 90 Improves Neuromuscular Function in Animal Models of Charcot Marie Tooth X1 Disease

Charcot-Marie-Tooth X1 (CMTX1) disease is an inherited peripheral neuropathy that arises from loss-of-function mutations in the protein connexin 32 (Cx32). CMTX1 currently lacks a pharmacologic approach toward disease management, and we have previously shown that modulating the expression of molecular chaperones using novologue therapy may provide a viable disease-modifying approach to treat metabolic and demyelinating neuropathies. Cemdomespib is an orally bioavailable novologue that manifests neuroprotective activity by modulating the expression of heat shock protein 70 (Hsp70). We examined if 1 to 5 months of daily cemdomespib therapy may improve neuropathic symptoms in three mouse models of CMTX1 (Cx32 deficient (Cx32def), T55I-Cx32def, and R75W-Cx32 mice). Daily drug therapy significantly improved motor nerve conduction velocity (MNCV) and grip strength in all three models, but the compound muscle action potential was only improved in Cx32def mice. Drug efficacy required Hsp70 as improvements in MNCV, and the grip strength was abrogated in Cx32def × Hsp70 knockout mice. Five months of novologue therapy was associated with improved neuromuscular junction morphology, femoral motor nerve myelination, reduction in foamy macrophages, and a decrease in Schwann cell c-jun levels. To determine if c-jun may be downstream of Hsp70 and necessary for drug efficacy, c-jun expression was specifically deleted in Schwann cells of Cx32def mice. While the deletion of c-jun worsened the neuropathy, cemdomespib therapy remained effective in improving MNCV and grip strength. Our data show that cemdomespib therapy improves CMTX1-linked neuropathy in an Hsp70-dependent but a c-jun-independent manner and without regard to the nature of the underlying Cx32 mutation.

Specific Activation of Yamanaka Factors via HSF1 Signaling in the Early Stage of Zebrafish Optic Nerve Regeneration

In contrast to the case in mammals, the fish optic nerve can spontaneously regenerate and visual function can be fully restored 3-4 months after optic nerve injury (ONI). However, the regenerative mechanism behind this has remained unknown. This long process is reminiscent of the normal development of the visual system from immature neural cells to mature neurons. Here, we focused on the expression of three Yamanaka factors (Oct4, Sox2, and Klf4: OSK), which are well-known inducers of induced pluripotent stem (iPS) cells in the zebrafish retina after ONI. mRNA expression of OSK was rapidly induced in the retinal ganglion cells (RGCs) 1-3 h after ONI. Heat shock factor 1 (HSF1) mRNA was most rapidly induced in the RGCs at 0.5 h. The activation of OSK mRNA was completely suppressed by the intraocular injection of HSF1 morpholino prior to ONI. Furthermore, the chromatin immunoprecipitation assay showed the enrichment of OSK genomic DNA bound to HSF1. The present study clearly showed that the rapid activation of Yamanaka factors in the zebrafish retina was regulated by HSF1, and this sequential activation of HSF1 and OSK might provide a key to unlocking the regenerative mechanism of injured RGCs in fish.

Characterizing Primary transcriptional responses to short term heat shock in paired fraternal lymphoblastoid lines with and without Down syndrome

Heat shock stress induces genome wide changes in transcription regulation, activating a coordinated cellular response to enable survival. Using publicly available transcriptomic and proteomic data sets comparing individuals with and without trisomy 21, we noticed many heat shock genes are up-regulated in blood samples from individuals with trisomy 21. Yet no major heat shock response regulating transcription factor is encoded on chromosome 21, leaving it unclear why trisomy 21 itself would cause a heat shock response, or how it would impact the ability of blood cells to subsequently respond when faced with heat shock stress. To explore these issues in a context independent of any trisomy 21 associated co-morbidities or developmental differences, we characterized the response to heat shock of two lymphoblastoid cell lines derived from brothers with and without trisomy 21. To carefully compare the chromatin state and the transcription status of these cell lines, we measured nascent transcription, chromatin accessibility, and single cell transcript levels in the lymphoblastoid cell lines before and after acute heat shock treatment. The trisomy 21 cells displayed a more robust heat shock response after just one hour at 42°C than the matched disomic cells. We suggest multiple potential mechanisms for this increased heat shock response in lymphoblastoid cells with trisomy 21 including the possibility that cells with trisomy 21 may exist in a hyper-reactive state due to chronic stresses. Whatever the mechanism, abnormal heat shock response in individuals with Down syndrome may hobble immune responses during fever and contribute to health problems in these individuals.

Flt3- and Tie2-Cre tracing identifies regeneration in sepsis from multipotent progenitors but not hematopoietic stem cells

In response to infections and stress, hematopoiesis rapidly enhances blood and immune cell production. The stage within the hematopoietic hierarchy that accounts for this regeneration is unclear under natural conditions in vivo. We analyzed by differentiation tracing, using inducible Tie2- or Flt3-driven Cre recombinase, the roles of mouse hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs). During polymicrobial sepsis, HSCs responded transcriptionally and increased their proliferation and cell death, yet HSC differentiation rates remained at steady-state levels. HSC differentiation was also independent from the ablation of various cellular compartments-bleeding, the antibody-mediated ablation of granulocytes or B lymphocytes, and genetic lymphocyte deficiency. By marked contrast, the fate mapping of MPPs in polymicrobial sepsis identified these cells as a major source for accelerated myeloid cell production. The regulation of blood and immune cell homeostasis by progenitors rather than stem cells may ensure a rapid response while preserving the integrity of the HSC population.

Cisplatin-induced HSF1-HSP90 axis enhances the expression of functional PD-L1 in oral squamous cell carcinoma

Immune checkpoint inhibitor-based cancer immunotherapy has provided an additional therapeutic option for oral squamous cell carcinoma (OSCC) with recurrence or distant metastases. However, further improvement of OSCC treatment is required to develop the optimal combination or order for chemoradiotherapy and immunotherapy. Along with the accumulation of clinical knowledge and evidence, it is also essential to clarify the biological impact of chemo-radiotherapeutic agents on the cancer immune microenvironment. In this study, we investigated the effects of cisplatin (CDDP), a key therapeutic agent for OSCC, on programmed death-ligand 1 (PD-L1) expression in OSCC lines. Although CDDP treatment increased the surface levels of PD-L1 on OSCC cell lines, the gene and total protein expression levels of PD-L1 were not altered. We also demonstrated that the phosphorylation of heat shock factor 1 and heat shock protein 90 was involved in this process. In addition, CDDP-induced PD-L1 attenuated the target-specific cytotoxic T lymphocyte reaction to OSCC. These results provide an immunobiological basis for the response of OSCC to CDDP and will contribute to our biological understanding of the action of novel combination therapy including immunotherapy together with platinum-based chemotherapy for OSCC.

Analysis of Potential Genes and Economic Parameters Associated with Growth and Heat Tolerance in Sheep (Ovis aries)

This study explored the potential genes and economic factors that might be associated with growth and heat tolerance in two sheep breeds. Data on growth performance from the third month to six months of age were obtained based on records. In comparison to Aboudeleik lambs, Barki lambs developed considerably greater starting body weight, final body weight, final body weight gain, daily weight gain, and percentage increase in BW/month. Single nucleotide polymorphisms (SNPs) were found between lambs of the two breeds using PCR-DNA sequencing of CAST, LEP, MYLK4, MEF2B, STAT5A, TRPV1, HSP90AB1, HSPB6, HSF1, ST1P1, and ATP1A1 genes. Lambs from each breed were divided into groups based on detected SNPs in genes related to growth. The least squares means of the differentiated groups revealed a significant correlation of detected SNPs with growth and heat tolerance attributes (p ≤ 0.05). Barki lambs elicited greater total variable costs, total costs, total return, and net return values. The Barki sheep provided the best economic efficiency value when comparing the percentage difference between net profit and economic efficiency. Together with economic considerations, SNPs found may be used as proxies for marker-assisted selection of the best breed of sheep for traits related to growth and heat tolerance.

HSF1, Aging, and Neurodegeneration

Heat shock factor 1 (HSF1) is a master transcription regulator that mediates the induction of heat shock protein chaperones for quality control (QC) of the proteome and maintenance of proteostasis as a protective mechanism in response to stress. Research in this particular area has accelerated dramatically over the past three decades following successful isolation, cloning, and characterization of HSF1. The intricate multi-protein complexes and transcriptional activation orchestrated by HSF1 are fundamental processes within the cellular QC machinery. Our primary focus is on the regulation and function of HSF1 in aging and neurodegenerative diseases (ND) which represent physiological and pathological states of dysfunction in protein QC. This chapter presents an overview of HSF1 structural, functional, and energetic properties in healthy cells while addressing the deterioration of HSF1 function viz-à-viz age-dependent and neuron-specific vulnerability to ND. We discuss the structural domains of HSF1 with emphasis on the intrinsically disordered regions and note that disease proteins associated with ND are often structurally disordered and exquisitely sensitive to changes in cellular environment as may occur during aging. We propose a hypothesis that age-dependent changes of the intrinsically disordered proteome likely hold answers to understand many of the functional, structural, and organizational changes of proteins and signaling pathways in aging - dysfunction of HSF1 and accumulation of disease protein aggregates in ND included.Structured AbstractsIntroduction: Heat shock factor 1 (HSF1) is a master transcription regulator that mediates the induction of heat shock protein chaperones for quality control (QC) of the proteome as a cyto-protective mechanism in response to stress. There is cumulative evidence of age-related deterioration of this QC mechanism that contributes to disease vulnerability.

OBJECTIVES

Herein we discuss the regulation and function of HSF1 as they relate to the pathophysiological changes of protein quality control in aging and neurodegenerative diseases (ND).

METHODS

We present an overview of HSF1 structural, functional, and energetic properties in healthy cells while addressing the deterioration of HSF1 function vis-à-vis age-dependent and neuron-specific vulnerability to neurodegenerative diseases.

RESULTS

We examine the impact of intrinsically disordered regions on the function of HSF1 and note that proteins associated with neurodegeneration are natively unstructured and exquisitely sensitive to changes in cellular environment as may occur during aging.

CONCLUSIONS

We put forth a hypothesis that age-dependent changes of the intrinsically disordered proteome hold answers to understanding many of the functional, structural, and organizational changes of proteins - dysfunction of HSF1 in aging and appearance of disease protein aggregates in neurodegenerative diseases included.

Understanding the molecular mechanisms that regulate pancreatic cancer stem cell formation, stemness and chemoresistance: A brief overview

Pancreatic cancer is one of the most aggressive cancers worldwide due to the resistances to conventional therapies and early metastasis. Recent research has shown that cancer stem cell populations modulate invasiveness, recurrence, and drug resistance in various cancers, including pancreatic cancer. Pancreatic cancer stem cells (PaCSCs) are characterized by their high plasticity and self-renewal capacities that endow them with unique metabolic, metastatic, and chemoresistant properties. Understanding the exact molecular and signaling mechanisms that underlay malignant processes in PaCSCs is instrumental for developing novel therapeutic modalities that overcome the limitations of current therapeutic regimens. In this paper, we provide an updated review of the latest research in the field and summarize the current knowledge of PaCSCs characteristics, cellular metabolism, stemness, and drug resistance. We explore how the crosstalk between the TME and PaCSCs influences stemness. We also highlight some of the key signalling pathways involved in PaCSCs stemness and drug evasion. The aim of this review is to explore how PaCSCs develop, maintain their properties, and drive tumor relapse in PC. The last section explores some of the latest therapeutic strategies aimed at targeting PaCSCs.

Hyper-transcription of heat shock factors and heat shock proteins safeguard caprine cardiac cells against heat stress

The present study was undertaken to document the transcriptional abundance of heat shock factors and heat shock proteins and their role in survivability of caprine cardiac cells during heat stress. Cardiac tissues were collected from different goats (n = 6) and primary cardiac cell culture was done in an atmosphere of 5% CO₂ and 95% air at 38.5 °C. Cardiac cells accomplished 70-75% confluence after 72 h of incubation. Confluent cardiac cells were exposed to heat stress at 42 °C for 0 (control), 20, 60, 100 and 200 min. Quantitative RT-PCR for β2m (internal control), heat shock factors (HSF1, HSF2, HSF4, HSF5), heat shock proteins (HSP10, HSP40), and Caspase-3 was done and their transcriptional abundance was assessed by Pfaffl method. Transcriptional abundance of HSF1, HSF2, and HSF4 did not change at 20 min, increased (P < 0.05) from 60 to 200 min and reached zenith at 200 min of heat exposure. However, transcriptional abundance of HSF5 was gradually escalated (P < 0.05) from 20 to 200 min and registered highest at 200 min of heat exposure. Transcriptional abundance of HSP10 and HSP40 followed an similar pattern like that of HSF5. Transcriptional abundance of Caspase-3 was significantly down-regulated at 200 min of heat exposure. It could be speculated that over-expression of HSFs and HSPs might have reduced Caspase-3 expression at 200 min of heat exposure suggesting their involvement in cardiac cells survival under heat stress. Moreover, hyper-expression of HSFs and HSPs could maintain the integrity and endurance of cardiac tissues of goats under heat stress.

HSF1 expression in tumor-associated macrophages promotes tumor cell proliferation and indicates poor prognosis in esophageal squamous cell carcinoma

PURPOSE

Tumor-associated macrophages (TAMs), are crucial for the survival and development of tumor cells. Heat shock factor 1 (HSF1) is a potent, complex carcinogenesis modulator, and esophageal cancer (EC) patients have a bad prognosis when HSF1 is highly expressed. HSF1's clinical importance and biological role in TAMs are still unknown.

METHODS

The HSF1 expression profile and patient survival information were analyzed from the TCGA database. The infiltration of different types of immune cells in EC was evaluated based on HSF1 gene expression by Sangerbox 3.0. Immunochemistry was employed to assess HSF1 protein expression in 134 individuals with esophageal squamous cell carcinoma (ESCC), proceeded by association with clinicopathological variables. The role of macrophage-driven HSF1 were observed using HSF1-knockdown THP1 cells.

RESULTS

High level of HSF1 have a poorer prognosis in individuals with EC. The expressing level of HSF1 was positively related to infiltration of M2 macrophages (P < 0.05). The expression of HSF1 in macrophages was an independent factor for DFS (P = 0.002) and OS (P = 0.002) in ESCC cases. HSF1 was up-regulated in IL-4 stimulation THP1 cells in a time-dependent manner. Under the heat stimulation condition, THP1-derived macrophages were more sensitive than tumor cells. Compared to IL-4 induced-THP1 cells control, the HSF1 knockdown in THP1 cell inhibited the growth and proliferation of ESCC cells.

CONCLUSIONS

The up-regulation of HSF1 was more rapid and could affect the proliferation of tumor cells in IL4-induced macrophages. The expression of HSF1 in TAMs can also serve as a marker for ESCC prognosis.

Transcriptomic Analysis on the Effects of Altered Water Temperature Regime on the Fish Ovarian Development of Coreius guichenoti under the Impact of River Damming

Field investigation indicated that the reduction in fish spawning was associated with the alteration in water temperatures, even a 2-3 °C monthly difference due to reservoir operations. However, the physiological mechanism that influences the development of fish ovary (DFO) remains unclear. Thus, experiments of Coreius guichenoti were conducted at three different temperatures, optimal temperature (~20 °C, N) for fish spawning, lower (~17 °C, L), and higher (~23 °C, H), to reveal the effects of altered water temperature on the DFO. Comparisons were made between the L and N (LvsN) conditions and H and N (HvsN) conditions. Transcriptomic analysis differentially expressed transcripts (DETs) related to heat stress were observed only in LvsN conditions, indicating that the DFO showed a stronger response to changes in LvsN than in HvsN conditions. Upregulation of DETs of vitellogenin receptors in N temperature showed that normal temperature was conducive to vitellogenin entry into the oocytes. Other temperature-sensitive DETs, including microtubule, kinesin, dynein, and actin, were closely associated with cell division and material transport. LvsN significantly impacted cell division and nutrient accumulation in the yolk, whereas HvsN only influenced cell division. Our results highlight the impact of altered water temperature on the DFO, thereby providing insights for future reservoir operations regarding river damming and climate change and establishing fish conservation measures.

The Thermal Stress Coping Network of the Nematode Caenorhabditis elegans

Response to hyperthermia, highly conserved from bacteria to humans, involves transcriptional upregulation of genes involved in battling the cytotoxicity caused by misfolded and denatured proteins, with the aim of proteostasis restoration. C. elegans senses and responds to changes in growth temperature or noxious thermal stress by well-defined signaling pathways. Under adverse conditions, regulation of the heat shock response (HSR) in C. elegans is controlled by a single transcription factor, heat-shock factor 1 (HSF-1). HSR and HSF-1 in particular are proven to be central to survival under proteotoxic stress, with additional roles in normal physiological processes. For years, it was a common belief that upregulation of heat shock proteins (HSPs) by HSF-1 was the main and most important step toward thermotolerance. However, an ever-growing number of studies have shown that targets of HSF-1 involved in cytoskeletal and exoskeletal integrity preservation as well as other HSF-1 dependent and independent pathways are equally important. In this review, we follow the thermal stimulus from reception by the nematode nerve endings till the activation of cellular response programs. We analyze the different HSF-1 functions in HSR as well as all the recently discovered mechanisms that add to the knowledge of the heat stress coping network of C. elegans.

Natural Products Targeting Hsp90 for a Concurrent Strategy in Glioblastoma and Neurodegeneration

Glioblastoma multiforme (GBM) is one of the most common aggressive, resistant, and invasive primary brain tumors that share neurodegenerative actions, resembling many neurodegenerative diseases. Although multiple conventional approaches, including chemoradiation, are more frequent in GBM therapy, these approaches are ineffective in extending the mean survival rate and are associated with various side effects, including neurodegeneration. This review proposes an alternative strategy for managing GBM and neurodegeneration by targeting heat shock protein 90 (Hsp90). Hsp90 is a well-known molecular chaperone that plays essential roles in maintaining and stabilizing protein folding to degradation in protein homeostasis and modulates signaling in cancer and neurodegeneration by regulating many client protein substrates. The therapeutic benefits of Hsp90 inhibition are well-known for several malignancies, and recent evidence highlights that Hsp90 inhibitors potentially inhibit the aggressiveness of GBM, increasing the sensitivity of conventional treatment and providing neuroprotection in various neurodegenerative diseases. Herein, the overview of Hsp90 modulation in GBM and neurodegeneration progress has been discussed with a summary of recent outcomes on Hsp90 inhibition in various GBM models and neurodegeneration. Particular emphasis is also given to natural Hsp90 inhibitors that have been evidenced to show dual protection in both GBM and neurodegeneration.

Association of HSF1 gene copy number variation with growth traits in the Ashidan yak

Copy Number Variation (CNV) is the major manner for the variation of genome structure, which is associated with numerous important traits. The heat shock factor 1 (HSF1) gene is a stress response transcriptional regulator. It participates in the heat shock response, simultaneously participated in the development of tissue. The objective of this research was to explore the influence of CNV of the HSF1 gene on the growth traits of the Ashidan yak. In this study, the growth traits (withers height, body weight, chest girth, and body length) of 274 Ashidan yaks were divided into four stages (6, 12, 18, and 30 months old). Moreover, quantitative polymerase chain reaction (qPCR) was exploited for determining the HSF1 gene relative expression level, and SPSS software was utilized for the statistical analysis. The outcomes indicated that HSF1-CNV was significantly associated with body length (p < 0.05) and was extremely significant associated with withers height (p < 0.01) of 18-month-old Ashidan yaks. Besides, the HSF1 relative expression in heart and muscle was higher than that existed in other tissues (p < 0.01). The outcomes suggested that the CNV of HSF1 gene would affect the growth and development of the Ashidan yak, which is conducive to the early breeding of yak.

Antitumor Activities of Aqueous Cinnamon Extract on 5637 Cell Line of Bladder Cancer through Glycolytic Pathway

Background

Pharmacotherapy with medicinal plants is a promising approach to treat cancer. Cinnamon is a medicinal plant whose properties have been proven in various fields of medical sciences. Among its biological activities, its antioxidant and antiviral effects can be mentioned. In this study, the antitumor effects of Cinnamon with a focus on glucose metabolism in bladder cancer carcinoma cell-line 5637 were investigated.

Methods

Aqueous extract of Cinnamon was prepared from Cinnamon bark. Bladder cancer 5637cell line were treated with different concentrations of aqueous extract of Cinnamon. MTT was used to evaluate cell viability at 24, 48, and 72 h. The concentration of 1.25, 2.50, and 5 mg/ml was used. Apoptosis was assessed with Hochest33258 staining. For evaluating of aqueous extract of Cinnamon effect on glycolysis, the gene expression of epidermal growth factor receptor 2 (ErbB2), heat shock protein transcription factor1 (HSF1), and lactate dehydrogenase A (LDHA), as well as protein levels of HSF1 and LDHA, LDH activity, glucose consumption, and lactate production, were measured.

Results

Aqueous extract of Cinnamon significantly decreased ErbB2, HSF1, and LDHA gene expression and also decreased the protein level of HSF1 and LDHA, LDH activity, glucose consumption, and lactate production dose-dependently (p < 0.05).

Conclusion

Our finding showed that the aqueous extract of Cinnamon can inhibit proliferation in 5637 cells by inhibition of glycolysis and induction of apoptosis.

Characterization of thermo-physiological, hematological, and molecular changes in response to seasonal variations in two tropically adapted native cattle breeds of Bos indicus lineage in hot arid ambience of Thar Desert

The selection of climate resilient animal is necessary to secure the future of sustainable animal production. The present investigation therefore was an effort to unravel answers to the adaptation at physiological, hematological, and molecular levels in cows of hot arid region that helps them to survive harsh environment, to continue production and reproduction. This investigation was carried out in indicine cows over a period of one year, encompassing four seasons, wherein physiological data of 50 animals, hematological data of 15 animals, and gene expression profile of 5 animals from each of Sahiwal and Kankrej breeds per season was generated. In total, 5600 physiological observations, 1344 hematological observations, and 480 molecular samples were processed. The meteorological data revealed a high diurnal variation of temperature across seasons, with THI exceeding 80 during the months of summer and hot-humid seasons, indicating significant heat stress (HS). The physiological parameters showed an increasing trend with the incremental THI, with significantly (p < 0.05) higher values of rectal temperature (RT), respiration rate (RR), pulse rate (PR), and body surface temperature (BST) at ventral (VT), lateral (LT), dorsal (DT), and frontal (FT), in both breeds recorded during HS. The hematological pictures also revealed significant (p < 0.05) seasonal perturbations in erythrocytic and leucocytic parameters. Moreover, the molecular response was driven by a significant (p < 0.05) upregulation of all the key HSPs, HSP70, HSP90, HSP60, and HSP40, except HSP27 during the hotter months of summer and hot-humid seasons. The expression of HSF1, an important transcriptional regulator of  HSP70 was also significantly (p < 0.05) upregulated during summer season in both breeds. All the molecular chaperones revealed a significant upregulation during the summer season, followed by a decreasing trend by hot-humid season. The study indicated a well-developed thermotolerance mechanism in animals of both breeds, with Kankrej cows exhibiting better thermotolerance compared to Sahiwal cows.

Role of HSP70 chaperone in protein aggregate phenomenon of GNE mutant cells: Therapeutic lead for GNE Myopathy

Limited treatment options and research in understanding the pathomechanisms of rare diseases has raised concerns about their therapeutic development. One such poorly understood ultra-rare neuromuscular disorder is GNE Myopathy (GNEM) which is caused due to mutation in key sialic acid biosynthetic enzyme, GNE. Treatment with sialic acid or its derivatives/precursors slows the disease progression, but curative strategies need to be explored further. Pathologically, muscle biopsy samples of GNEM patients reveal rimmed vacuole formation due to aggregation of β-amyloid, Tau, presenilin proteins with unknown mechanism. The present study aims to understand the mechanism of protein aggregate formation in GNE mutant cells to decipher role of chaperones in disease phenotype. The pathologically relevant GNE mutations expressed as recombinant proteins in HEK cells was used as a model system for GNEM to estimate extent of protein aggregation. We identified HSP70, a chaperone, as binding partner of GNE. Downregulation of HSP70 with altered BAG3, JNK, BAX expression levels was observed in GNE mutant cells. The cell apoptosis was observed in GNE mutation specific manner. An activator of HSP70 chaperone, BGP-15, rescued the phenotypic defects due to GNE mutation, thereby, reducing protein aggregation significantly. The results were further validated in rat skeletal muscle cell lines carrying single Gne allele. Our study suggests that HSP70 activators can be a promising therapeutic target in the treatment of ultra-rare GNE Myopathy disease.

Copy Number Variation of Circulating Tumor DNA (ctDNA) Detected Using NIPT in Neoadjuvant Chemotherapy-Treated Ovarian Cancer Patients

Analysis of circulating tumor DNA (ctDNA) can be used to characterize and monitor cancers. Recently, non-invasive prenatal testing (NIPT) as a new next-generation sequencing (NGS)-based approach has been applied for detecting ctDNA. This study aimed to investigate the copy number variations (CNVs) utilizing the non-invasive prenatal testing in plasma ctDNA from ovarian cancer (OC) patients who were treated with neoadjuvant chemotherapy (NAC). The plasma samples of six patients, including stages II–IV, were collected during the pre- and post-NAC treatment that were divided into NAC-sensitive and NAC-resistant groups during the follow-up time. CNV analysis was performed using the NIPT via two methods “an open-source algorithm WISECONDORX and NextGENe software.” Results of these methods were compared in pre- and post-NAC of OC patients. Finally, bioinformatics tools were used for data mining from The Cancer Genome Atlas (TCGA) to investigate CNVs in OC patients. WISECONDORX analysis indicated fewer CNV changes on chromosomes before treatment in the NAC-sensitive rather than NAC-resistant patients. NextGENe data indicated that CNVs are not only observed in the coding genes but also in non-coding genes. CNVs in six genes were identified, including HSF1, TMEM249, MROH1, GSTT2B, ABR, and NOMO2, only in NAC-resistant patients. The comparison of these six genes in NAC-resistant patients with The Cancer Genome Atlas data illustrated that the total alteration frequency is amplification, and the highest incidence of the CNVs (≥35% based on TCGA data) is found in MROH1, TMEM249, and HSF1 genes on the chromosome (Chr) 8. Based on TCGA data, survival analysis showed a significant reduction in the overall survival among chemotherapy-resistant patients as well as a high expression level of these three genes compared to that of sensitive samples (all, p < 0.0001). The continued Chr8 study using WISECONDORX revealed CNV modifications in NAC-resistant patients prior to NAC therapy, but no CNV changes were observed in NAC-sensitive individuals. Our findings showed that low coverage whole-genome sequencing analysis used for NIPT could identify CNVs in ctDNA of OC patients before and after chemotherapy. These CNVs are different in NAC-sensitive and -resistant patients highlighting the potential application of this approach in cancer patient management.

Auxin-Inducible Degron System Reveals Temporal-Spatial Roles of HSF-1 and Its Transcriptional Program in Lifespan Assurance

HSF-1 is a key regulator of cellular proteotoxic stress response and is required for animal lifespan. In C. elegans, HSF-1 mediated heat shock response (HSR) declines sharply on the first day of adulthood, and HSF-1 was proposed to function primarily during larval stages for lifespan assurance based on studies using RNAi. The tissue requirement for HSF-1 in lifespan, however, is not well understood. Using the auxin-inducible degron (AID) system, we manage to uncouple the roles of HSF-1 in development and longevity. In wild-type animals, we find HSF-1 is required during the whole self-reproductive period for lifespan. This period is extended in long-lived animals that have arrested germline stem cells (GSC) or reduced insulin/IGF-1 signaling (IIS). While depletion of HSF-1 from any major somatic tissues during development results in severe defects, HSF-1 primarily functions in the intestine and likely neural system of adults to support lifespan. Finally, by combining AID and genome-wide transcriptional analyses, we find HSF-1 directly activates the transcription of constitutively-expressed chaperone and co-chaperone genes among others in early adulthood, which underlies its roles in longevity assurance.

Effects of pH alterations on stress- and aging-induced protein phase separation

Upon stress challenges, proteins/RNAs undergo liquid–liquid phase separation (LLPS) to fine-tune cell physiology and metabolism to help cells adapt to adverse environments. The formation of LLPS has been recently linked with intracellular pH, and maintaining proper intracellular pH homeostasis is known to be essential for the survival of organisms. However, organisms are constantly exposed to diverse stresses, which are accompanied by alterations in the intracellular pH. Aging processes and human diseases are also intimately linked with intracellular pH alterations. In this review, we summarize stress-, aging-, and cancer-associated pH changes together with the mechanisms by which cells regulate cytosolic pH homeostasis. How critical cell components undergo LLPS in response to pH alterations is also discussed, along with the functional roles of intracellular pH fluctuation in the regulation of LLPS. Further studies investigating the interplay of pH with other stressors in LLPS regulation and identifying protein responses to different pH levels will provide an in-depth understanding of the mechanisms underlying pH-driven LLPS in cell adaptation. Moreover, deciphering aging and disease-associated pH changes that influence LLPS condensate formation could lead to a deeper understanding of the functional roles of biomolecular condensates in aging and aging-related diseases.

Sirt3-Sod2-mROS-Mediated Manganese Triggered Hepatic Mitochondrial Dysfunction and Lipotoxicity in a Freshwater Teleost

Exposure to excessive manganese (Mn) is toxic to humans and animals. However, the toxic effects and mechanisms of excessive Mn influencing the vertebrates have been highly overlooked. In the present study, dietary Mn overload significantly increased hepatic lipid and Mn contents, decreased superoxide dismutase 2 (Sod2) activity, increased the Sod2 acetylation level, and induced mitochondrial dysfunction; Mn induced mitochondrial dysfunction through Mtf1/sirtuin 3 (Sirt3)-mediated acetylation of Sod2 at the sites K55 and K70. Meanwhile, mitochondrial oxidative stress was involved in Mn-induced lipotoxicity. Mechanistically, Mn-induced lipotoxicity was via oxidative stress-induced Hsf1 nucleus translocation and its DNA binding capacity to the regions of a peroxisome proliferator-activated receptor g (pparg) promoter, which in turn induced the transcription of lipogenic-related target genes. For the first time, our study demonstrated that Mn-induced hepatic lipotoxicity via a mitochondrial oxidative stress-dependent Hsf1/Pparg pathway and Mtf1/sirt3-mediated Sod2 acetylation participated in mitochondrial dysfunction. Considering that lipid metabolism and lipotoxicity are widely used as the biomarkers for environmental assessments of pollutants, our study provided innovative and important insights into Mn toxicological and environmental evaluation in aquatic environments.

Binding of the HSF-1 DNA-binding domain to multimeric C. elegans consensus HSEs is guided by cooperative interactions

The protein HSF-1 is the controlling transcription factor of the heat-shock response (HSR). Its binding to the heat-shock elements (HSEs) induces the strong upregulation of conserved heat-shock proteins, including Hsp70s, Hsp40s and small HSPs. Next to these commonly known HSPs, more than 4000 other HSEs are found in the promoter regions of C. elegans genes. In microarray experiments, few of the HSE-containing genes are specifically upregulated during the heat-shock response. Most of the 4000 HSE-containing genes instead are unaffected by elevated temperatures and coexpress with genes unrelated to the HSR. This is also the case for several genes related to the HSP chaperone system, like dnj-12, dnj-13, and hsp-1. Interestingly, several promoters of the dedicated HSR-genes, like F44E5.4p, hsp-16.48p or hsp-16.2p, contain extended HSEs in their promoter region, composed of four or five HSE-elements instead of the common trimeric HSEs. We here aim at understanding how HSF-1 interacts with the different promoter regions. To this end we purify the nematode HSF-1 DBD and investigate the interaction with DNA sequences containing these regions. EMSA assays suggest that the HSF-1 DBD interacts with most of these HSE-containing dsDNAs, but with different characteristics. We employ sedimentation analytical ultracentrifugation (SV-AUC) to determine stoichiometry, affinity, and cooperativity of HSF-1 DBD binding to these HSEs. Interestingly, most HSEs show cooperative binding of the HSF-1 DBD with up to five DBDs being bound. In most cases binding to the HSEs of inducible promoters is stronger, even though the consensus scores are not always higher. The observed high affinity of HSF-1 DBD to the non-inducible HSEs of dnj-12, suggests that constitutive expression may be supported from some promoter regions, a fact that is evident for this transcription factor, that is essential also under non-stress conditions.

Divergent regulatory roles of NuRD chromatin remodeling complex subunits GATAD2 and CHD4 in Caenorhabditis elegans

During proteotoxic stress, a pathway known as the heat shock response is induced to maintain protein-folding homeostasis or proteostasis. Previously, we identified the Caenorhabditis elegans GATAD2 ortholog, dcp-66, as a novel regulator of the heat shock response. Here, we extend these findings to show that dcp-66 positively regulates the heat shock response at the cellular, molecular, and organismal levels. As GATAD2 is a subunit of the nucleosome remodeling and deacetylase chromatin remodeling complex, we examined other nucleosome remodeling and deacetylase subunits and found that the let-418 (CHD4) nucleosome repositioning core also regulates the heat shock response. However, let-418 acts as a negative regulator of the heat shock response, in contrast to positive regulation by dcp-66. The divergent effects of these two nucleosome remodeling and deacetylase subunits extend to the regulation of other stress responses including oxidative, genotoxic, and endoplasmic reticulum stress. Furthermore, a transcriptomic approach reveals additional divergently regulated pathways, including innate immunity and embryogenesis. Taken together, this work establishes new insights into the role of nucleosome remodeling and deacetylase subunits in organismal physiology. We incorporate these findings into a molecular model whereby different mechanisms of recruitment to promoters can result in the divergent effects of nucleosome remodeling and deacetylase subunits.

Stress-responsive regulation of extracellular proteostasis

Genetic, environmental, and aging-related insults can promote the misfolding and subsequent aggregation of secreted proteins implicated in the pathogenesis of numerous diseases. This has led to considerable interest in understanding the molecular mechanisms responsible for regulating proteostasis in extracellular environments such as the blood and cerebrospinal fluid (CSF). Extracellular proteostasis is largely dictated by biological pathways comprising chaperones, folding enzymes, and degradation factors localized to the ER and extracellular space. These pathways limit the accumulation of nonnative, potentially aggregation-prone proteins in extracellular environments. Many reviews discuss the molecular mechanisms by which these pathways impact the conformational integrity of the secreted proteome. Here, we instead focus on describing the stress-responsive mechanisms responsible for adapting ER and extracellular proteostasis pathways to protect the secreted proteome from pathologic insults that challenge these environments. Further, we highlight new strategies to identify stress-responsive pathways involved in regulating extracellular proteostasis and describe the pathologic and therapeutic implications for these pathways in human disease.