Bioactive TNIIIA2 Sequence in Tenascin-C Is Responsible for Macrophage Foam Cell Transformation; Potential of FNIII14 Peptide Derived from Fibronectin in Suppression of Atherosclerotic Plaque Formation.

One of the extracellular matrix proteins, tenascin-C (TN-C), is known to be upregulated in age-related inflammatory diseases such as cancer and cardiovascular diseases. Expression of this molecule is frequently detected, especially in the macrophage-rich areas of atherosclerotic lesions; however, the role of TN-C in mechanisms underlying the progression of atherosclerosis remains obscure. Previously, we found a hidden bioactive sequence termed TNIIIA2 in the TN-C molecule and reported that the exposure of this sequence would be carried out through limited digestion of TN-C by inflammatory proteases.

Heat shock-induced heme oxygenase-1 expression in a mouse hepatoma cell line is dependent on HSF1 and modified by NRF2 and BACH1.

The induction mechanism of heme oxygenase-1 (HO-1) by heat shock (HS) is still unknown. Here, we discovered that HS activates the HO-1 expression in a mouse hepatoma cell line (Hepa 1-6). Knockdown experiments showed that the HS-induced HO-1 expression was dependent on HS factor 1 (HSF1).

Heme oxygenase-1 induction by heat shock in rat hepatoma cell line is regulated by the coordinated function of HSF1, NRF2 and BACH1.

The mechanism of heme oxygenase-1 (HO-1) induction by heat shock (HS) loading remains unclear. Here, we investigated the contribution of transcription factors to HS-induced HO-1 expression, using a rat hepatoma cell line (H-4-II-E). Our results demonstrated that HS treatment resulted in a marked induction of HO-1.

Visualization of the Redox Status of Cytosolic Glutathione Using the Organelle- and Cytoskeleton-Targeted Redox Sensors.

Glutathione is a small thiol-containing peptide that plays a central role in maintaining cellular redox homeostasis. Glutathione serves as a physiologic redox buffer by providing thiol electrons for catabolizing harmful oxidants and reversing oxidative effects on biomolecules. Recent evidence suggests that the balance of reduced and oxidized glutathione (GSH/GSSG) defines the redox states of Cys residues in proteins and fine-tunes their stabilities and functions.

NRF2 and HSF1 coordinately regulate heme oxygenase-1 expression.

Heme oxygenase-1 (HO-1) is an inducible enzyme responding to various stresses and has cytoprotective activities. Although HO-1 has been referred to as heat shock protein (HSP) 32, the heat-mediated induction of HO-1 varies among different species and cell lines. We examined the effects of heat shock on HO-1 expression in mouse embryonic fibroblast (MEF) cells deficient in heat shock factor 1 (HSF1) or nuclear factor-erythroid-2-related factor 2 (NRF2).

Local redox environment beneath biological membranes probed by palmitoylated-roGFP.

Production of reactive oxygen species (ROS) and consequent glutathione oxidation are associated with various physiological processes and diseases, including cell differentiation, senescence, and inflammation. GFP-based redox sensors provide a straight-forward approach to monitor ROS levels and glutathione oxidation within a living cell at the subcellular resolution. We utilized palmitoylated versions of cytosolic glutathione and hydrogen peroxide sensors (Grx1-roGFP2 and roGFP2-Orp1, respectively) and demonstrated a unique redox environment near biological membranes.

Thiol-based copper handling by the copper chaperone Atox1.

Human antioxidant protein 1 (Atox1) plays a crucial role in cellular copper homeostasis. Atox1 captures cytosolic copper for subsequent transfer to copper pumps in trans Golgi network, thereby facilitating copper supply to various copper-dependent oxidereductases matured within the secretory vesicles. Atox1 and other copper chaperones handle cytosolic copper using Cys thiols which are ideal ligands for coordinating Cu(I).

Prevention of Barrier Disruption by Heme Oxygenase-1 in Intestinal Bleeding Model.

In this study we investigated the effect of free heme, the local level of which was increased by bleeding, on the intestinal barrier function, using human epithelial colorectal adenocarcinoma cells (Caco-2). Our results show that the addition of hemin to the culture medium markedly disrupted the barrier function, which was significantly improved by glutamine supplementation. Although hemin treatment caused the increased expression of heme oxygenase (HO)-1, the inhibition of HO activity resulted in the aggravation of hemin-induced barrier dysfunction.

Chicken IL-6 is a heat-shock gene.

The febrile response is elicited by pyrogenic cytokines including IL-6 in response to microorganism infections and diseases in vertebrates. Mammalian HSF1, which senses elevations in temperature, negatively regulates the response by suppressing pyrogenic cytokine expression. We here showed that HSF3, an avian ortholog of mammalian HSF1, directly binds to and activates IL-6 during heat shock in chicken cells.

Glutamine protects intestinal barrier function of colon epithelial cells from ethanol by modulating Hsp70 expression.

In this study, we investigated the protective effect of glutamine on barrier dysfunction induced by ethanol, by using human epithelial colorectal adenocarcinoma cells (Caco-2). Our results show that addition of glutamine to culture medium significantly improved the disruption of integrity caused by ethanol, which was associated with increased expression of heat shock protein 70 (Hsp70). Ethanol exposure moderately activates heat shock factor 1 (HSF1), which was characterized by increased DNA-binding activity and phosphorylation status of HSF1.

Heat shock factor 2 is required for maintaining proteostasis against febrile-range thermal stress and polyglutamine aggregation.

Heat shock response is characterized by the induction of heat shock proteins (HSPs), which facilitate protein folding, and non-HSP proteins with diverse functions, including protein degradation, and is regulated by heat shock factors (HSFs). HSF1 is a master regulator of HSP expression during heat shock in mammals, as is HSF3 in avians. HSF2 plays roles in development of the brain and reproductive organs.

Heat shock transcription factor 1 inhibits expression of IL-6 through activating transcription factor 3.

The febrile response is a complex physiological reaction to disease, including a cytokine-mediated increase in body temperature and the activation of inflammatory systems. Fever has beneficial roles in terms of disease prognosis, partly by suppressing the expression of inflammatory cytokines. However, the molecular mechanisms underlining the fever-mediated suppression of inflammatory gene expression have not been clarified.

A novel mouse HSF3 has the potential to activate nonclassical heat-shock genes during heat shock.

The heat-shock response is characterized by the expression of a set of classical heat-shock genes, and is regulated by heat-shock transcription factor 1 (HSF1) in mammals. However, comprehensive analyses of gene expression have revealed very large numbers of inducible genes in cells exposed to heat shock. It is believed that HSF1 is required for the heat-inducible expression of these genes although HSF2 and HSF4 modulate some of the gene expression.

Analysis of HSF4 binding regions reveals its necessity for gene regulation during development and heat shock response in mouse lenses.

Heat shock transcription factors (HSFs) regulate gene expression in response to heat shock and in physiological conditions. In mammals, HSF1 is required for heat-mediated induction of classic heat shock genes; however, we do not know the molecular mechanisms by which HSF4 regulates gene expression or the biological consequences of its binding to chromatin. Here, we identified that HSF4 binds to various genomic regions, including the introns and distal parts of protein-coding genes in vivo in mouse lenses, and a substantial numbers of the regions were also occupied by HSF1 and HSF2.

Attenuation of progressive hearing loss in a model of age-related hearing loss by a heat shock protein inducer, geranylgeranylacetone.

Mechanisms of age-related hearing loss (ARHL) have not been elucidated as aging processes are extremely complex. Although oxidative stress and apoptotic cell death are involved in progression of ARHL, number of trial to treat ARHL is limited. Heat shock response is characterized by induction of heat shock proteins (HSPs) in response to stresses such as heat shock, which diminishes during aging.

Heat shock transcription factor 1 is required for maintenance of ciliary beating in mice.

Heat shock transcription factors (HSFs) maintain protein homeostasis through regulating expression of heat shock proteins, especially in stressed conditions. In addition, HSFs are involved in cellular differentiation and development by regulating development-related genes, as well as heat shock genes. Here, we showed chronic sinusitis and mild hydrocephalus in postnatal HSF1-null mice, which are associated with impaired mucociliary clearance and cerebrospinal flow, respectively.

Heat shock transcription factor 1 opens chromatin structure of interleukin-6 promoter to facilitate binding of an activator or a repressor.

Heat shock transcription factor 1 (HSF1) not only regulates expression of heat shock genes in response to elevated temperature, but is also involved in developmental processes by regulating genes such as cytokine genes. However, we did not know how HSF1 regulates non-heat shock genes. Here, we show that constitutive HSF1 binding to the interleukin (IL)-6 promoter is necessary for its maximal induction by lipopolysaccharide (LPS) stimulation in mouse embryo fibroblasts and peritoneal macrophages.

A novel HSF1-mediated death pathway that is suppressed by heat shock proteins.

Heat shock response is an adoptive response to proteotoxic stress, and a major heat shock transcription factor 1 (HSF1) has been believed to protect cells from cell death by inducing heat shock proteins (Hsps) that assist protein folding and prevent protein denaturation. However, it is revealed recently that HSF1 also promotes cell death of male germ cells. Here, we found a proapoptotic Tdag51 (T-cell death associated gene 51) gene as a direct target gene of HSF1.

Maintenance of olfactory neurogenesis requires HSF1, a major heat shock transcription factor in mice.

Heat shock transcription factors (HSFs) play roles not only in heat shock response but also in development of the reproductive organs, brain, and lens. Here, we analyzed sensory organs and found abnormalities of the olfactory epithelium in adult HSF1-null mice, which is developmentally related to the lens. The olfactory epithelium was normal until postnatal 3 weeks but was not maintained later than 4 weeks in HSF1-null mice.

Active HSF1 significantly suppresses polyglutamine aggregate formation in cellular and mouse models.

Polyglutamine diseases are inherited neurodegenerative diseases characterized by misfolding and aggregation of proteins possessing expanded polyglutamine repeats. As overexpression of some heat shock protein (Hsp) suppresses polyglutamine aggregates and cell death, it is assumed that combined overexpression of Hsps will suppress that more effectively. Here, we examined the impact of active forms of heat shock transcription factor 1 (HSF1), which induces a set of Hsps, on polyglutamine inclusion formation and disease progression.

HSF4 is required for normal cell growth and differentiation during mouse lens development.

The heat shock transcription factor (HSF) family consists of three members in mammals and regulates expression of heat shock genes via a heat shock element. HSF1 and HSF2 are required for some developmental processes, but it is unclear how they regulate these processes. To elucidate the mechanisms of developmental regulation by HSFs, we generated mice in which the HSF4 gene is mutated.

Feeding induces expression of heat shock proteins that reduce oxidative stress.

Heat shock proteins (Hsps) are induced in response to various kinds of environmental and physiological stresses. However, it is unclear whether Hsps play roles in protecting cells in the digestive organs against xenobiotic chemicals. Here, we found that feeding induces expression of a set of Hsps specifically in the mouse liver and intestine by activating heat shock transcription factor 1 (HSF1).

Impaired IgG production in mice deficient for heat shock transcription factor 1.

Heat shock factor 1 (HSF1) is a major transactivator of heat shock proteins in response to heat shock, and it is also involved in oogenesis, spermatogenesis, and placental development. However, we do not know the molecular mechanisms controlling developmental processes. In this study, we found that HSF1-null mice exhibited a significant decrease in the T cell-dependent B cell response.

Hsp25, a member of the Hsp30 family, promotes inclusion formation in response to stress.

Protein aggregates are oligomeric complexes of misfolded proteins, and serve as the seeds of inclusion bodies termed aggresomes in the cells. Heat shock proteins (Hsps) prevent misfolding and aggregate formation. Here, we found that only avian Hsp25 dominantly accumulated in the aggresomes induced by proteasome inhibition.