Role Of Heat Shock Protein 27 Research Articles

Mechanistic insights into heat shock protein 27, a potential therapeutic target for cardiovascular diseases.

Heat shock protein 27 (HSP27) is a small chaperone protein that is overexpressed in a variety of cellular stress states. It is involved in regulating proteostasis and protecting cells from multiple sources of stress injury by stabilizing protein conformation and promoting the refolding of misfolded proteins. Previous studies have confirmed that HSP27 is involved in the development of cardiovascular diseases and plays an important regulatory role in this process. Herein, we comprehensively and systematically summarize the involvement of HSP27 and its phosphorylated form in pathophysiological processes, including oxidative stress, inflammatory responses, and apoptosis, and further explore the potential mechanisms and possible roles of HSP27 in the diagnosis and treatment of cardiovascular diseases. Targeting HSP27 is a promising future strategy for the treatment of cardiovascular diseases.

Discovery of Novel HSP27 Inhibitors as Prospective Anti-Cancer Agents Utilizing Computer-Assisted Therapeutic Discovery Approaches.

Heat shock protein 27 (HSP27) is a protein that works as a chaperone and an antioxidant and is activated by heat shock, environmental stress, and pathophysiological stress. However, HSP27 dysregulation is a characteristic of many human cancers. HSP27 suppresses apoptosis and cytoskeletal reorganization. As a result, it is recognized as a critical therapeutic target for effective cancer therapy. Despite the effectiveness of multiple HSP27 inhibitors in pre-clinical investigations and clinical trials, no HSP27 inhibitor has progressed to the anticancer phase of the development. These difficulties have mostly been attributable to existing anticancer therapies’ inability to target oncogenic HSP27. Highly selective HSP27 inhibitors with higher effective-ness and low toxicity led to the development of combination techniques that include computer-aided assisted therapeutic discovery and design. This study emphasizes the most recent results and roles of HSP27 in cancer and the potential for utilizing an anticancer chemical database to uncover novel compounds to inhibit HSP27.

TAT-HSP27 Peptide Improves Neurologic Deficits via Reducing Apoptosis After Experimental Subarachnoid Hemorrhage.

Cell apoptosis plays an important role in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Heat shock protein 27 (HSP27), a member of the small heat shock protein (HSP) family, is induced by various stress factors and exerts protective role on cells. However, the role of HSP27 in brain injury after SAH needs to be further clarified. Here, we reported that HSP27 level of cerebrospinal fluid (CSF) is increased obviously at day 1 in patients with aneurysmal SAH (aSAH) and related to the grades of Hunt and Hess (HH), World Federation of Neurological Surgeons (WFNS), and Fisher score. In rat SAH model, HSP27 of CSF is first increased and then obviously declined; overexpression of HSP27, not knockdown of HSP27, attenuates SAH-induced neurological deficit and cell apoptosis in the basal cortex; and overexpression of HSP27 effectively suppresses SAH-elevated activation of mitogen-activated protein Kinase Kinase 4 (MKK4), the c-Jun N-terminal kinase (JNK), c-Jun, and caspase-3. In an in vitro hemolysate-damaged cortical neuron model, HSP2765−90 peptide effectively inhibits hemolysate-induced neuron death. Furthermore, TAT-HSP2765−90 peptide, a fusion peptide consisting of trans-activating regulatory protein (TAT) of HIV and HSP2765−90 peptide, effectively attenuates SAH-induced neurological deficit and cell apoptosis in the basal cortex of rats. Altogether, our results suggest that TAT-HSP27 peptide improves neurologic deficits via reducing apoptosis.

Protective Effect of Trehalose Against H2O2-induced Cytotoxicity and Oxidative Stress in PC-12 Cell Line and the Role of Heat Shock Protein-27

Background: Oxidative stress has been shown to be an important factor, which plays a significant role in the pathogenesis of neurodegenerative disorders. Heat Shock Protein-27 (HSP-27) has been implicated in antioxidant responses against oxidative stress. Trehalose is a natural disaccharide widely used in a variety of food products with demonstrated protective effects against several neurodegenerative diseases. This study investigated the effects of trehalose on antioxidant responses, and the gene expressions for HSP-27 and caspase-3 against hydrogen peroxide (H2O2) induced oxidative injury in PC-12 cell line. Methods: The PC-12 cells were treated with various concentrations of H2O2 and trehalose for 24hr. The cell viability was assessed, using MTT and Lactate Dehydrogenase (LDH) release assays. Moreover, the activity of Catalase (CAT) and Glutathione Peroxidase (GPx) enzymes, and the Malondialdehyde (MDA) levels were determined. In addition, the levels of HSP-27 and caspase-3 gene expressions were measured. Results: The results indicated that the pretreatment with trehalose increased cell survival against the H2O2-induced oxidative injury. Furthermore, trehalose elevated the CAT and GPx activities and reduced MDA levels compared to that of control group (P˂0.05). Moreover, trehalose upregulated the HSP-27 gene expression, while reducing the expression of caspase-3 gene compared to that of the untreated cells (P˂0.05). All of these biochemical changes were found to be dose-dependent for trehalose. Conclusion: Based on the study findings, trehalose had the capacity to attenuate the oxidative stress and cell injury. Therefore, trehalose may be suggested as a therapeutic agent to treat neurodegenerative disorders caused by oxidative stress damages.

Promotion of the Differentiation of Dental Pulp Stem Cells into Oligodendrocytes by Knockdown of Heat Shock Protein 27

Stem cell-based therapy has been evaluated in many different clinical trials for various diseases. This capability was applied in various neurodegenerative diseases, such as multiple sclerosis, which is characterized by demyelination, axonal injury, and neuronal loss. Dental pulp stem cells (DPSCs) are mesenchymal stem cells from the oral cavity that have been studied with potential application for the regeneration of different tissues. Heat shock protein 27 (HSP27) regulates neurogenesis in the process of neural differentiation of placenta multipotent stem cells. Here, we hypothesize that HSP27 expression is also critical for the neural differentiation of DPSCs. An evaluation of the possible role of HSP27 in the differentiation of DPSCs was performed using gene knockdown and neural immunofluorescent staining. We found that HSP27 played a role in the differentiation of DPSCs and that knockdown of HSP27 in DPSCs rendered cells to oligodendrocyte progenitors; i.e., small hairpin specific for HSP27 DPSCs exhibited NG2-positive immunoreactivity and gave rise to oligodendrocytes or type-2 astrocytes. This neural differentiation of DPSCs may have clinical significance in the treatment of patients with neurodegenerative diseases. In conclusion, our data provide an example of the oligodendrocyte differentiation of a DPSC model, which may be applied in human regenerative medicine.

Targeting Heat Shock Protein 27 in Cancer: A Druggable Target for Cancer Treatment?

Heat shock protein 27 (HSP27), induced by heat shock, environmental, and pathophysiological stressors, is a multi-functional protein that acts as a protein chaperone and an antioxidant. HSP27 plays a significant role in the inhibition of apoptosis and actin cytoskeletal remodeling. HSP27 is upregulated in many cancers and is associated with a poor prognosis, as well as treatment resistance, whereby cells are protected from therapeutic agents that normally induce apoptosis. This review highlights the most recent findings and role of HSP27 in cancer, as well as the strategies for using HSP27 inhibitors for therapeutic purposes.

Heat shock protein 27 influences the anti-cancer effect of curcumin in colon cancer cells through ROS production and autophagy activation

The problem of therapeutic resistance and chemotherapeutic efficacy is tricky and critical in the management of colorectal cancer (CRC). Curcumin is a promising anti-cancer agent. Heat shock protein 27 (HSP27) is correlated with CRC progression and is said to affect CRC response to different therapies. However, the role of HSP27 on the therapeutic efficacy of curcumin remains unknown. HSP27 was silenced using small hairpin RNA (shRNA) technique. The cytotoxic and apoptotic effects of curcumin were assessed by sulforhodamine B (SRB) colorimetric assay, flow cytometric cell cycle analysis, and annexin V/propidium iodide (PI) double-labeling assays. Total reactive oxygen species (ROS)/superoxide and autophagy detection were performed, and the levels of apoptosis-related proteins were examined by Western blotting. It was found that the silencing of HSP27 (HSP27-KD) resulted in increased treatment resistance to curcumin in CRC cells. In addition, cell cycle analysis showed that the curcumin treatment caused cell cycle arrest at the G2/M phase in the control group, and apoptosis was reduced in the HSP27-KD group. Curcumin treatment also resulted in a decrease in anti-apoptotic proteins, p-Akt, Akt, Bcl-2 and p-Bad, and increase in pro-apoptotic proteins Bad and c-PARP levels in the control cells but not in the HSP27-KD cells. This was also followed by low reactive oxygen/nitrogen species (ROS/RNS), superoxide and autophagy induction levels in the HSP27-KD cells as compared to the control cells. Therefore, as silencing of HSP27 increases curcumin resistance by reducing apoptosis and reactive oxidative stress production, HSP27 is a potential selective target for curcumin treatment in CRC.

HSP27 regulates TGF-β mediated lung fibroblast differentiation through the Smad3 and ERK pathways.

Idiopathic pulmonary fibrosis(IPF) is a chronic lethal interstitial lung disease with unknown etiology. Recent studies have indicated that heat-shock protein27(HSP27) contributes to the pathogenesis of IPF through the regulation of epithelial-mesenchymal transition(EMT). However, the expression and role of HSP27 in fibroblasts during pulmonary fibrogenesis has not been investigated to date, at least to the best of our knowledge. In this study, we examined the expression of HSP27 in fibrotic lung tissue and fibroblasts from bleomycin(BLM)-challenged mice and human lung fibroblasts treated with transforming growth factor-β(TGF-β). The results revealed that the expression of HSP27 was significantly increased in fibrotic lung tissue and fibroblasts from BLM-challenged mice. Invitro, TGF-β stimulated HSP27 expression in and the differentiation of human lung fibroblasts. The knockdown of Smad3 expression or nuclear factor-κBp65 subunit attenuated the TGF-β-induced increase in HSP27 expression and the differentiation of human lung fibroblasts. In addition, the knockdown of HSP27 expression attenuated the TGF-β-induced activation of ERK and Smad3, and inhibited the differentiation of human lung fibroblasts. On the whole, the findings of our study demonstrate that HSP27 expression is upregulated in lung fibroblasts during pulmonary fibrosis, and subsequently, HSP27 modulates lung fibroblast differentiation through the Smad3 and ERK pathways.

Extracellular Release and Signaling by Heat Shock Protein 27: Role in Modifying Vascular Inflammation.

Heat shock protein 27 (HSP27) is traditionally viewed as an intracellular chaperone protein with anti-apoptotic properties. However, recent data indicate that a number of heat shock proteins, including HSP27, are also found in the extracellular space where they may signal via membrane receptors to alter gene transcription and cellular function. Therefore, there is increasing interest in better understanding how HSP27 is released from cells, its levels and composition in the extracellular space, and the cognate cell membrane receptors involved in effecting cell signaling. In this paper, the knowledge to date, as well as some emerging paradigms about the extracellular function of HSP27 is presented. Of particular interest is the role of HSP27 in attenuating atherogenesis by modifying lipid uptake and inflammation in the plaque. Moreover, the abundance of HSP27 in serum is an emerging new biomarker for ischemic events. Finally, HSP27 replacement therapy may represent a novel therapeutic opportunity for chronic inflammatory disorders, such as atherosclerosis.

Abstract 2905: HSP27 as a potential factor to determine the fate of Gemcitabine- induced autophagy in osteosarcoma: Survival vs. death

Abstract Lung metastasis constitutes the main cause of death in osteosarcoma (OS) patients. Survival has not improved in the past ten years. Therefore, new therapeutic strategies are needed. We previously reported that aerosol Gemcitabine (GCB) has a significant therapeutic effect against OS lung metastases. There was however, a subset of cells that fail to respond to GCB treatment resulting in persistent small isolated lung metastases that led to relapse and death. The mechanisms underlying OS resistance to GCB have remained elusive. Autophagy, a catabolic process involved in cellular homeostasis, has emerged as an important mechanism involved in cancer cells response to treatment. However, whether autophagy plays a role in OS resistance to GCB is unknown. Thus, the purpose of this study is to investigate the role of autophagy in OS lung metastases resistance to GCB. In this study, LM7 and CCH-OS-D human OS cells were treated with GCB and induction of autophagy was evaluated. GCB-induced autophagy was demonstrated by formation of acidic vesicular organelles (AVOs), conversion of microtubule-associated light chain 3 (LC3I/LC3II), increase in Beclin 1 (BECN1) and decrease in p62/SQSTM1 protein expression. Additionally, formation of autophagic vacuoles was confirmed by electron microscopy. GCB-induced autophagy also resulted in the inhibition of AKT /mTOR phosphorylation, suggesting this signaling pathway as a possible underlying mechanism responsible for GCB-induced autophagy in OS. To test whether autophagy contributes to OS cells survival to GCB, we determined the impact of autophagy inhibition on the sensitivity of OS cells to GCB. Sensitivity of LM7 cells to GCB was greatly enhanced after autophagy inhibition by the pharmacologic inhibitor hydroxychloroquine (HCQ) and shRNA targeting BECN1, suggesting autophagy as a pro-survival mechanism. Interestingly, inhibition of autophagy in CCH-OS-D cells decreased cell sensitivity to GCB, suggesting that GCB-induced autophagy contributed to cell death. Better understanding of the molecular pathways that govern the process of autophagy will allow identification of new strategies to enhance chemotherapeutic efficacy. Our preliminary work showed that the phosphorylation of Heat Shock protein 27 (HSP27) was significantly higher in GCB-treated LM7 cells when compared to CCH-OS-D GCB-treated cells, indicating a potential role of HSP27 in outlining the role of autophagy in osteosarcoma cells. Taken together, these results suggest that autophagy can be induced by GCB in OS cells and that inhibition of autophagy can lead to either increase or decrease OS cells sensitivity to Gemcitabine. Citation Format: Janice M. Santiago-O'Farrill, Mario Hollomon, Eugenie Kleinerman, Nancy Gordon. HSP27 as a potential factor to determine the fate of Gemcitabine- induced autophagy in osteosarcoma: Survival vs. death. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2905. doi:10.1158/1538-7445.AM2015-2905

Expression of one important chaperone protein, heat shock protein 27, in neurodegenerative diseases

IntroductionMany neurodegenerative diseases are characterised by accumulations of misfolded proteins that can colocalise with chaperone proteins (for example, heat shock protein 27 (HSP27)), which might act as modulators of protein aggregation.MethodsThe role of HSP27 in the pathogenesis of neurodegenerative disorders such as frontotemporal lobar degeneration (FTLD), Alzheimer’s disease (AD) and motor neuron disease (MND) was investigated. We used immunohistochemical and Western blot analysis to determine the distribution and amount of this protein in the frontal and temporal cortices of diseased and control subjects.ResultsHSP27 immunostaining presented as accumulations of granules within neuronal and glial cell perikarya. Patients with AD and FTLD were affected more often, and showed greater immunostaining for HSP27, than patients with MND and controls. In FTLD, there was no association between HSP27 and histological type. The neuropathological changes of FTLD, AD and MND were not immunoreactive to HSP27. Western blot analysis revealed higher HSP27 expression in FTLD than in controls, but without qualitative differences in banding patterns.ConclusionsThe pattern of HSP27 immunostaining observed may reflect the extent of ongoing neurodegeneration in affected brain areas and is not specific to FTLD, AD or MND. It may represent an accumulation of misfolded, damaged or unwanted proteins, awaiting or undergoing degradation.

An investigation of heat shock protein 27 and P-glycoprotein mediated multi-drug resistance in breast cancer using liquid chromatography-tandem mass spectrometry-based targeted proteomics.

LC/MS/MS-based targeted proteomics turns out to be a promising quantification approach for the study of proteins in the preclinical and clinical environment. Unfortunately, rare studies applied this technology to detect multiple associated proteins or protein modification in one experiment. This study demonstrated the potential of LC/MS/MS-based targeted proteomics to understand the cell events in a more accurate context of biological system. By the quantitative time-course analysis of HSP27 and its phosphorylated forms at sites of Ser15 and Ser82, the possible role of HSP27 in P-gp mediated MDR was suggested. Further development of targeted proteomics in future may provide more insight into signal transduction pathways upon perturbation of a protein network or changes to a panel of proposed biomarkers in a given disease state.

Heat shock protein 27 regulates human prostate cancer cell motility and metastatic progression

Prostate cancer (PCa) is the most common form of cancer in American men. Mortality from PCa is caused by the movement of cancer cells from the primary organ to form metastatic tumors at distant sites. Heat shock protein 27 (HSP27) is known to increase human PCa cell invasion and its overexpression is associated with metastatic disease. The role of HSP27 in driving PCa cell movement from the prostate to distant metastatic sites is unknown. Increased HSP27 expression increased metastasis as well as primary tumor mass. In vitro studies further examined the mechanism of HSP27-induced metastatic behavior. HSP27 did not affect cell detachment, adhesion, or migration, but did increase cell invasion. Cell invasion was dependent upon matrix metalloproteinase 2 (MMP-2), whose expression was increased by HSP27. In vivo, HSP27 induced commensurate changes in MMP-2 expression in tumors. These findings demonstrate that HSP27 drives metastatic spread of cancer cells from the prostate to distant sites, does so across a continuum of expression levels, and identifies HSP27-driven increases in MMP-2 expression as functionally relevant. These findings add to prior studies demonstrating that HSP27 increases PCa cell motility, growth and survival. Together, they demonstrate that HSP27 plays an important role in PCa progression.

Heat shock protein 27 attenuates neointima formation and accelerates reendothelialization after arterial injury and stent implantation: importance of vascular endothelial growth factor up‐regulation

Elevated serum heat shock protein 27 (HSP27) levels are atheroprotective; however, the role of HSP27 after arterial injury is unknown. Human endothelial progenitor cells (EPCs) were treated with recombinant (r)HSP27 (50 μg/ml) or its inactive C1 terminus, and gene expression was characterized before functional studies were performed in vitro and in vivo. Vascular endothelial growth factor (VEGF) was markedly up-regulated by rHSP27 (10- and 6-fold increases in mRNA and secretion, respectively). Pretreatment of EPCs with rHSP27 resulted in a 60% reduction in reendothelialization (RE) time in a scratch assay, an effect that was blocked with VEGF-neutralizing antibodies. Mice overexpressing HSP27 demonstrated more robust mobilization of EPCs at the time of arterial injury, as well as a 67% increase in RE and a 45% reduction in neointima (NI) formation at 28 d. Implantation of rHSP27-eluting stents in rabbit carotid arteries resulted in a marked improvement in RE at 7 and 28 d and transient attenuation of NI formation by 42% at 7 d. Hence, extracellular HSP27 up-regulated VEGF and improved EPC migration in vitro. Augmented systemic or local levels of HSP27 markedly improved RE after vascular injury, an effect that is of particular relevance to the safety profile of vascular stents.

Role of heat shock protein-27 in breast cancer genesis and development

Role of heat shock protein-27 in breast cancer genesis and development

HSP27 Protects the Blood-Brain Barrier Against Ischemia-Induced Loss of Integrity

Loss of integrity of the blood-brain barrier (BBB) in stroke victims initiates a devastating cascade of events including extravasation of blood-borne molecules, water, and inflammatory cells deep into brain parenchyma. Thus, it is important to identify mechanisms by which BBB integrity can be maintained in the face of ischemic injury in experimental stroke. We previously demonstrated that the phylogenetically conserved small heat shock protein 27 (HSP27) protects against transient middle cerebral artery occlusion (tMCAO). Here we show that HSP27 transgenic overexpression also maintains the integrity of the BBB in mice subjected to tMCAO. Extravasation of endogenous IgG antibodies and exogenous FITC-albumin into the brain following tMCAO was reduced in transgenic mice, as was total brain water content. HSP27 overexpression abolished the appearance of TUNEL-positive profiles in microvessel walls. Transgenics also exhibited less loss of microvessel proteins following tMCAO. Notably, primary endothelial cell cultures were rescued from oxygen-glucose deprivation (OGD) by lentiviral HSP27 overexpression according to four viability assays, supporting a direct effect on this cell type. Finally, HSP27 overexpression reduced the appearance of neutrophils in the brain and inhibited the secretion of five cytokines. These findings reveal a novel role for HSP27 in attenuating ischemia/reperfusion injury - the maintenance of BBB integrity. Endogenous upregulation of HSP27 after ischemia in wild-type animals may exert similar protective functions and warrants further investigation. Exogenous enhancement of HSP27 by rational drug design may lead to future therapies against a host of injuries, including but not limited to a harmful breach in brain vasculature.

Heat shock protein 27 and its role in retinal ganglion cell apoptosis in rat high intraocular pressure model

Background Glaucoma is common blinding eye diseases characterized by chronic loss of retinal ganglion cells(RGCs).Currently glaucoma pathogenesis is not completely understood,heat shock protein 27 ( HSP27 )may be associated with the pathogenesis of glaucomatous optic neuropathy. Objective Through the establishment of a rat model of high intraocular pressure,detection of the expression of HSP27 antibody in serum and RGCs apoptosis to investigate the role of HSP27 in RGCs apoptosis. Methods Fifty-one clean Wistar rats were divided into high intraocular pressure group (34 rats)and sham operation group( 17 rats)using a random number table.An animal model of high intraocular pressure was established in the right eye by the application of bipolar underwater electrocoagulation on vein of sclera surface in the experimental group,and rats with conjunctiva incision only without electric coagulation were served as sham operation (control).The intraocular pressure of rats of the both groups including experimental and control rats was measured 1,2,4,6,8 weeks after operation and then the rats were sacrificed.1 ml serum was collected from these rats to determine the concentration of HSP27 antibody.The retinas of the rats were isolated and homogenated for the extraction and analysis of the retinal protein by Western blot.Apoptosis of RGCs were assayed by TUNEL.The use of the experimental animals followed the Regulations for the Administration of Affair Concerning Experimental Animals by Kunming Medical Collegc. Results Intraocular pressure was elevated significantly after modeling and remained a high value during the expcrimental duration,showing a significant difference among the different groups ( F =318.502,P＜0.01 ).However,no significant change in intraocular pressure before and after operation in the sham-operation group ( F =2.076,P ＞ 0.05 ).The serum concentration of HSP27 antibody was increased significantly overtime from 1,2,4,6 to 8 weeks after the surgery applied,with a significant difference among various time points( F =154.221,P＜0.01 ),but no obvious difference was seen in the shamoperation group( F =0.422,P＞0.05 ).Importantly,Apoptosis rate of RGCs in the experimental eyes was significant higher as the time prolong after intraocular elevated(x2=856.12,P＜0.05 ).The positive rate of RGCs apoptosis in the rats with high intraocular pressure group was elevated significantly compared to the rats in the sham operation group(P＜0.05). Conclusions High intraocular pressure induces the expressions of HSP27 in retina and the accumulation of HSP27 antibody in rats serum;the elevated HSP27 is associated with the increased cell death in RGCs. Key words: Glaucoma; Heat shock protein 27 antibody; Retina ganglion cell; Apoptosis

Tissue microarray analysis to evaluate the role of heat shock protein 27 as a potential biomarker in pancreatic cancer.

e21053 Background: Heat shock protein 27 (HSP27) is a stress-inducible protein preventing the accumulation of misfolded proteins and participating in the regulation of apoptosis. The role of HSP27 as a biomarker has been investigated in a variety of tumor entities, but little is known about its significance in pancreatic cancer. Applying tissue microarray (TMA) analysis, we correlated HSP27 protein expression with clinical-pathological parameters in surgical specimen from 86 pancreatic cancer patients. Methods: Immunohistochemistry, TMA, database analysis. Results: We found HSP27 expression in 49% of pancreatic cancer samples. HSP27 was predominantly expressed in the cytoplasm. Additionally, membranous staining was observed in single cases. There was no association between HSP27 expression and gender, age, grading, lymph node status, metastases, resection status or tumor size. However, HSP27 expression was strongly correlated with better post-operative survival. Consistently, Kaplan-Meier analyses confirmed a significant influence of HSP27 expression on survival. Other parameters affecting survival were expectedly lymph node status, metastases, and tumor size. The univariate analyses regarding HSP27 expression were reproducible using multivariate Cox-regression analyses adjusted for age, gender, grading, resection status, lymph node status, metastases, and tumor size. Finally, backward selection, excluding the least significant factor one at a time, further supported HSP27 expression to be an independent survival factor in pancreatic cancer. Conclusions: Applying TMA analyses of 86 patients with pancreatic cancer, we identified HSP27 as an independent prognostic biomarker in this tumor type. Additional clinical implications could arise from future studies clarifying the underlying mechanism for this observation, especially in regard to a potential association between HSP27 expression and response to chemotherapy. No significant financial relationships to disclose.

Transduction of recombinant heat shock protein 27 increases contractility of vascular smooth muscle

Heat shock protein 27 (HSP27) is a stress induced cytoprotective protein, which has been shown be involved in contraction, stress fiber formation, and reorganization of actin cytoskeleton. In this study, the role of HSP27 on contractility in rat aortic vascular smooth muscle (VSM) tissue was examined by using a transducible recombinant HSP27 (rPTDHSP27). Human HSP27 cDNA, that was fused with a protein transduction domain and 6x Histidine tag at the N terminal end, was expressed in Escherichia coli and purified using a metal chelating affinity column. The purified protein was verified through Western blot and HPLC ESI MS/MS. VSM rings were equilibrated in a muscle bath, and contracted with norepinephrine (NE) (1–1000 nM) with or without 3.8 μM rPTDHSP27 and force generated was measured. Norepinephrine induced a dose dependent contraction, which was enhanced with the pretreatment of rPTDHSP27 (84.1% compared to 16.9% in the control with 16 nM NE). The concentration needed to produce maximal contraction was 10 fold lower when the tissue was pretreated with rPTDHSP27 (88% at 666 nM compared to 96% at 66 nM, for control and rPTDHSP27 treated rings respectively). NIH RO1 70715

Heat shock protein 27 interacts with vimentin and prevents insolubilization of vimentin subunits induced by cadmium

Vimentin is an intermediate filament that regulates cell attachment and subcellular organization. In this study, vimentin filaments were morphologically altered, and its soluble subunits were rapidly reduced via cadmium chloride treatment. Cadmium chloride stimulated three major mitogen-activated protein kinases (MAPKs): extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, and led apoptotic pathway via caspase-9 and caspase-3 activations. In order to determine whether MAPKs were involved in this cadmium-induced soluble vimentin disappearance, we applied MAPK-specific inhibitors (PD98059, SP600125, SB203580). These inhibitors did not abolish the cadmium-induced soluble vimentin disappearance. Caspase and proteosome degradation pathway were also not involved in soluble vimentin disappearance. When we observed vimentin levels in soluble and insoluble fractions, soluble vimentin subunits shifted to an insoluble fraction. As we discovered that heat-shock protein 27 (HSP27) was colocalized and physically associated with vimentin in unstressed cells, the roles of HSP27 with regard to vimentin were assessed. HSP27-overexpressing cells prevented morphological alterations of the vimentin filaments, as well as reductions of soluble vimentin, in the cadmium-treated cells. Moreover, HSP27 antisense oligonucleotide augmented these cadmium-induced changes in vimentin. These findings indicate that HSP27 prevents disruption of the vimentin intermediate filament networks and soluble vimentin disappearance, by virtue of its physical interaction with vimentin in cadmium-treated SK-N-SH cells.