Hsp22 ameliorates lipopolysaccharide-induced myocardial injury by inhibiting inflammation, oxidative stress, and apoptosis.

Sepsis-induced myocardial dysfunction (SIMD) is ubiquitous in septic shock patients and is associated with high morbidity and mortality rates. Heat shock protein 22 (Hsp22), which belongs to the small HSP family of proteins, is involved in several biological functions. However, the function of Hsp22 in lipopolysaccharide (LPS)-induced myocardial injury is not yet established. This study was aimed at investigating the underlying mechanistic aspects of Hsp22 in myocardial injury induced by LPS. In this study, following the random assignment of male C57BL/6 mice into control, LPS-treated, and LPS + Hsp22 treated groups, relevant echocardiograms and staining were performed to scrutinize the cardiac pathology. Plausible mechanisms were proposed based on the findings of the enzyme-linked immunosorbent assay and Western blotting assay. A protective role of Hsp22 against LPS-induced myocardial injury emerged, as evidenced from decreased levels of creatinine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and enhanced cardiac function. The post-LPS administration-caused spike in inflammatory cytokines (IL-1ß, IL-6, TNF-α and NLRP3) was attenuated by the Hsp22 pre-treatment. In addition, superoxide dismutase (SOD) activity and B-cell lymphoma-2 (Bcl2) levels were augmented by Hsp22 treatment resulting in lowering of LPS-induced oxidative stress and cardiomyocyte apoptosis. In summary, the suppression of LPS-induced myocardial injury by Hsp22 overexpression via targeting of inflammation, oxidative stress, and apoptosis in cardiomyocytes paves the way for this protein to be employed in the therapy of SIMD.

Heat shock protein 22 modulates NRF1/TFAM-dependent mitochondrial biogenesis and DRP1-sparked mitochondrial apoptosis through AMPK-PGC1α signaling pathway to alleviate the early brain injury of subarachnoid hemorrhage in rats.

Mitochondrial dysfunction has been widely accepted as a detrimental factor in subarachnoid hemorrhage (SAH)-induced early brain injury (EBI), which is eminently related to poor neurologic function outcome. Previous studies have revealed that enhancement of heat shock protein 22 (hsp22) under conditions of stress is a friendly mediator of mitochondrial homeostasis, oxidative stress and apoptosis, thus accelerating neurological recovery. However, no study has confirmed whether hsp22 attenuates mitochondrial stress and apoptosis in the setting of SAH-induced EBI. Our results indicated that endogenous hsp22, p-AMPK/AMPK, PGC1α, TFAM, Nrf1 and Drp1 were significantly upregulated in cortical neurons in response to SAH, accompanied by neurologic impairment, brain edema, neuronal degeneration, lower level of mtDNA and ATP, mitochondria-cytosol translocation of cytochrome c, oxidative injury and caspase 3-involved mitochondrial apoptosis. However, exogenous hsp22 maintained neurological function, reduced brain edema, improved oxidative stress and mitochondrial apoptosis, these effects were highly dependent on PGC1α-related mitochondrial biogenesis/fission, as evidenced by co-application of PGC1α siRNA. Furthermore, we demonstrated that blockade of AMPK with dorsomorphin also compromised the neuroprotective actions of hsp22, along with the alterations of PGC1α and its associated pathway molecules. These data revealed that hsp22 exerted neuroprotective effects by salvaging mitochondrial function in an AMPK-PGC1α dependent manner, which modulates TFAM/Nrf1-induced mitochondrial biogenesis with positive feedback and DRP1-triggered mitochondrial apoptosis with negative feedback, further reducing oxidative stress and brain injury. Boosting the biogenesis and repressing excessive fission of mitochondria by hsp22 may be an efficient treatment to relieve SAH-elicited EBI.

Hsp22 with an N-Terminal Domain Truncation Mediates a Reduction in Tau Protein Levels.

Misfolding, aggregation and accumulation of proteins are toxic elements in the progression of a broad range of neurodegenerative diseases. Molecular chaperones enable a cellular defense by reducing or compartmentalizing these insults. Small heat shock proteins (sHsps) engage proteins early in the process of misfolding and can facilitate their proper folding or refolding, sequestration, or clearance. Here, we evaluate the effects of the sHsp Hsp22, as well as a pseudophosphorylated mutant and an N-terminal domain deletion (NTDΔ) variant on tau aggregation in vitro and tau accumulation and aggregation in cultured cells. Hsp22 wild-type (WT) protein had a significant inhibitory effect on heparin-induced aggregation in vitro and the pseudophosphorylated mutant Hsp22 demonstrated a similar effect. When co-expressed in a cell culture model with tau, these Hsp22 constructs significantly reduced soluble tau protein levels when transfected at a high ratio relative to tau. However, the Hsp22 NTDΔ protein drastically reduced the soluble protein expression levels of both tau WT and tau P301L/S320F even at lower transfection ratios, which resulted in a correlative reduction of the triton-insoluble tau P301L/S320F aggregates.

Role of heat shock protein 22 in the protective effect of geranylgeranylacetone in response to oxidized-LDL.

OBJECTIVE: The aim was to investigate the role and potential mechanism of geranylgeranylacetone (GGA) in the development of atherosclerosis, and to explore the role of heat shock protein 22 (HSP22) in mediating GGA effect. METHODS: Human coronary artery endothelial cell (HCAEC) was used for in vitro study. RNA interference was applied to suppress HSP22 in the cells. Cellular apoptosis and intracellular level of reactive oxygen species (ROS) were detected by flow cytometer, and proteins of HSP22, NF-κB, eNOS, and ICAM-1 were assessed by immunoblotting. HSP22-/-//ApoE-/-, and HSP22+/+//ApoE-/- mice were used to investigate the effect of GGA in the animal model of atherosclerosis. Atherosclerotic lesion of the mice aortas was evaluated by Oil Red O staining and H&E staining. RESULTS: GGA significantly inhibited HCAEC apoptosis in response to oxidized-LDL (ox-LDL), but stimulated HSP22 synthesis in the cells. Transfection of HSP22-siRNA in the cells resulted in complete blockage of the GGA effect on apoptosis. GGA also significantly inhibited ROS, NF-κB, and ICAM-1 in the cells transfected control siRNA, but not in the cells transfected with HSP22-siRNA. Atherosclerotic plaque in the aorta was significantly less in the wild type (WT) animals treated with GGA as stained either by Oil Red O or by H&E staining, but not in the HSP22-KO mice. GGA significantly inhibited expression of NF-κB and ICAM-1 in the WT mice, but not in the HSP22-KO mice. CONCLUSION: GGA-induced HSP22, and inhibited ox-LDL-induced apoptosis as well as expression of NF-κB and ICAM-1 in the HCAECs. GGA also attenuated formation of atherosclerotic plaques in mice aorta. Suppression of HSP22 by siRNA resulted in blockage of the GGA inhibition on apoptosis or stimulation on NF-κB and ICAM-1. These findings suggested that GGA protects endothelial cells from injury in response to ox-LDL and block atherosclerotic development in mice aorta through induction of HSP22.

Heat shock protein 22 reduces phenylephrine-induced cardiomyocytes hypertrophy / 中华急诊医学杂志

Objective To investigate the effect of Hsp22 on phenylephrine-induced cardiomyocytes hypertrophy.Methods Primary rat myocardial cells were isolated and cultured in Department of Cardiology,the First Affiliated Hospital of Zhengzhou University.Cells were divided into four groups randomly:Control group,model group,treatment group with 1 μg/mL Hsp22,and treatment group with 10 μg/mL Hsp22.Phenylephrine stimuli was used to induce cardiomyocytes hypertrophy model.Cell viability was measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Cardiomyocytes surface area was evaluated by α-actin immunofluorescence staining.Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the transcription level of hypertrophic markers.Reactive oxygen species level was detected by 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probe.Apoptosis was detected by TUNEL staining.Signal pathway protein expression was detected by Western blot.SPSS 13.0 was used for statistical analysis.Data were expressed as mean + standard deviation.All data were analyzed by one-way ANOVA between groups.Comparisons between two groups were performed using LSD-t test.A P＜0.05 was considered statistically significant.Results Different concentrations of Hsp22 had no effect on cardiomyocytes viability (F=6.622;P＞0.05).Phenylephrine stimulation significantly increased cardiomyocytes area (t=10.80;P＜0.05),increased the transcription level of hypertrophy markers atrial natriuretic peptide (t=37.72;P＜0.05),type B natriuretic peptide (t=16.85;P＜0.05),and myosin heavy chain beta (t=41.53;P＜0.05).Different concentrations of Hsp22 significantly reduced cardiomyocytes area (PE+ 1 μg/mL Hsp22 t=4.018;P＜0.05;PE+10 μg/mL Hsp22 t=10.80;P＜0.05),reduced the transcription level of hypertrophic markers atrial natriuretic peptide (PE+1 μg/mL Hsp22 t=27.12,P＜0.05;PE+10 μg/mL Hsp22 t=37.72,P＜0.05),type B natriuretic peptide (PE+1 μg/mL Hsp22 t=4.82,P＜0.05;PE+10 μg/mL Hsp22 t=12.74,P＜0.05),and myosin heavy chain beta (PE+1 μg/mL Hsp22 t=23.68,P＜0.05;PE+10 μg/mL Hsp22 t=30.54,P＜0.05).Westem blot showed that Hsp22 increased the activation of AMP-activated protein kinase α (PE+1 μg/mL Hsp22 t=5.89,P＜0.05;PE+10 μg/mL Hsp22 t=5.88,P＜0.05),reduced mTOR phosphorylation level (PE+1 μg/mL Hsp22 t=16.80,P＜0.05;PE+10.μg/mL Hsp22 t=20.46,P＜0.05).Conclusions Hsp22 inhibits cardiomyocytes hypertrophy by activating AMP-activated protein kinase α.Hsp22 may become a potential anti-hypertrophic drug.

Role of HSP22 in atherosclerosis induced by high-fat diet and effects of statin / 中国病理生理杂志

AIM:To evaluate the role of heat shock protein 22(HSP22)in atherosclerosis(AS)induced by high-fat diet and in the intervention with atorvastatin(Ator).METHODS: Total 3 groups of 8 ~9-week-old ApoE-/-, HSP22-/-ApoE-/-and HSP22 +ApoE-/-male mice were used,with 18 mice in each group.After 1 week of adaptive feeding, the mice in each group were randomly divided into 2 subgroups: control group, and Ator group, HSP22 knockout group (KO group)and HSP22 knockout with Ator treatment group(KO+Ator group),and HSP22 overexpression group(Tg group)and HSP22 overexpression with Ator treatment group(Tg+Ator group).Atro at 10 mg· kg-1-d-1was administered to the mice in all Ator groups from the 5th week.The mice in the control groups were given saline.All these mice were fed for 13 weeks.Oil red O staining and HE staining of the aortic wall of the mice were used to measure the atherosclerotic le-sion burdens.The protein levels of HSP22,NF-κB, eNOS, ICAM-1 and IL-6 in the aorta and serum were examined by Western blot,immunohistochemistry and ELISA.RESULTS:Aortic Oil red O staining and HE staining showed that the relative area of aorta plaque in Tg group was less than that in KO group(P<0.05).The protein expression of HSP22 in Tg group was significantly higher than that in control group and KO group,and its expression in control group was signifi-cantly higher than that in KO group.The protein expression of eNOS in Tg group and control group was significantly higher than that in KO group.The protein expression of NF-κB and ICAM-1 in control group was significantly decreased as com-pared with KO group,and their expression was significantly higher than that in Tg group.No difference of serum IL-6 level was found among Tg group,KO group and control group.CONCLUSION:HSP22 gene deletion up-regulates the expres-sion of NF-κB and ICAM-1,and down-regulates the expression of eNOS,leading to accelerating AS.HSP22 overexpression decreases the expression of NF-κB and ICAM-1 and increases the expression of eNOS,thus attenuating AS development. HSP22 gene deletion partially limits the role of Ator in the expression of NF-κB,ICAM-1 and eNOS.HSP22 overexpression amplifies the reduced expression of ICAM-1 by the intervention with Ator,and further attenuates AS development.

Heat shock protein 22 (HSPB8) reduces the migration of hepatocellular carcinoma cells through the suppression of the phosphoinositide 3-kinase (PI3K)/AKT pathway.

Small heat shock proteins (HSPs) regulate a variety of cell functions. Among them, HSP22 and HSP20 are recognized to be ubiquitously expressed in various tissues. With regard to hepatocellular carcinoma (HCC) cells, we previously reported that phosphorylated HSP20 plays a suppressive role in transforming growth factor (TGF)-α-induced cell migration and invasion. In the present study, we investigated whether or not HSP22 is implicated in HCC cell migration. We detected HSP22 protein expression both in human HCC tumor (189.9±68.4ng/mg protein) and the adjacent non-tumor liver tissues (167.9±94.6ng/mg protein). The cases of low-quantity HSP22 protein level group (88.3≧ng/mg protein, the optimum cut-off value of HSP22) were increased in tumor tissues compared with the adjacent non-tumor tissues. The migration of human HCC-derived HuH-7 cells stimulated by TGF-α or hepatocyte growth factor (HGF) was significantly enhanced by the knockdown of HSP22 expression. Down-regulation of HSP22 protein in the cells markedly strengthened the AKT phosphorylation induced by TGF-α or HGF. Inhibitors of the phosphoinositide 3-kinase (PI3K)/AKT pathway, which suppressed the TGF-α-induced migration, significantly reduced the amplification by HSP22 knockdown. PI3K but not AKT was coimmunoprecipitated with HSP22 in HuH-7 cells. In addition, in human HCC tissues, a significantly lower HSP22 protein level in tumor tissues than in adjacent non-tumor tissues was observed more frequently in cases of moderately or poorly differentiated HCC than well-differentiated HCC. Taken together, our results strongly suggest that HSP22 represses HCC progression, especially HCC cell migration, by the down-regulation of the PI3K/AKT signaling pathway.

Heat shock protein 22 (HSPB8) limits TGF-ß-stimulated migration of osteoblasts.

Heat shock proteins (HSPs) are induced in response to various physiological and environmental conditions such as chemical and heat stress, and recognized to function as molecular chaperones. HSP22 (HSPB8), a low-molecular weight HSP, is ubiquitously expressed in many cell types. However, the precise role of HSP22 in bone metabolism remains to be clarified. In the present study, we investigated whether HSP22 is implicated in the transforming growth factor-ß (TGF-ß)-stimulated migration of osteoblast-like MC3T3-E1 cells. Although protein levels of HSP22 were clearly detected in unstimulated MC3T3-E1 cells, TGF-ß failed to induce the protein levels. The TGF-ß-stimulated migration was significantly up-regulated by knockdown of HSP22 expression. The cell migration stimulated by platelet-derived growth factor-BB was also enhanced by HSP22 knockdown. SB203580, an inhibitor of p38 mitogen-activated protein kinase, PD98059, an inhibitor of MEK1/2, or SP600125, an inhibitor of stress-activated protein kinase/c-Jun N-terminal kinase had no effects on the TGF-ß-induced migration. SIS3, a specific inhibitor of TGF-ß-dependent Smad3 phosphorylation, significantly reduced the migration with or without TGF-ß stimulation. Smad2, Smad3, Smad4 or Smad7 was not coimmunoprecipitated with HSP22. On the other hand, the TGF-ß-induced Smad2 phosphorylation was enhanced by HSP22 down-regulation. The protein levels of TGF-ß type II receptor (TGF-ß RII) but not TGF-ß type I receptor (TGF-ß RI) was significantly up-regulated in HSP22 knockdown cells compared with those in the control cells. However, the levels of TGF-ß RII mRNA in HSP22 knockdown cells were little different from those of the control cells. Neither TGF-ß RI nor TGF-ß RII was coimmunoprecipitated with HSP22. SIS3 reduced the amplification by HSP22 knockdown of the TGF-ß-stimulated cell migration almost to the basal level. Our results strongly suggest that HSP22 functions as a negative regulator in the TGF-ß-stimulated migration of osteoblasts via suppression of the Smad-dependent pathway, resulting from modulating the protein levels of TGF-ß RII.

Aortic expression of HSP22, TNF-αand eNOS in rats with hyperlipi-demia and effects of atorvastatin / 中国病理生理杂志

AIM:To establish a rat hyperlipidemia model for studying the aortic expression of heat shock protein 22 (HSP22), tumor necrosis factor alpha (TNF-α) and endothelial nitric oxide synthase (eNOS) and the effect of atorvasta-tin intervention.METHODS:Hyperlipidemia model was established in SD rats.Afterwards, the rats were divided into nor-mal control group, high fat group and high fat+atorvastatin intervention group.The expression of HSP22 and TNF-αin the rat aortas was detected by immunohistochemical assay and the expression of eNOS was assessed by Western blotting.RE-SULTS:No detectable expression of HSP22 and TNF-αin the normal control group was observed.However, the expression of HSP22 and TNF-αwas positive in the high fat group and the atorvastatin intervention group.The mean densities of HSP22 and TNF-αpositive particles were significant lower in the atorvastatin intervention group as compared with high fat group ( both P<0.05) .The expression of eNOS protein in the high fat group and atorvastatin intervention group was significantly lower than that in normal control group (P<0.01).However, no marked difference of eNOS protein expression between high fat group and atorvastatins intervention group was observed.CONCLUSION:The expression of HSP22 and TNF-αin the rat aortas is increased in the hyperlipidemia rat model.This effect can be restored by atorvastatin treatment.The expression of eNOS in the rat aortas is decreased in the hyperlipidemia rat model, but this tendency could not be attenuated by atorvastatin.

Salvianolate increases heat shock protein expression in a cerebral ischemia-reperfusion injury model.

Stroke remains a worldwide health problem. Salvianolate exerts a protective effect in various mi-crocirculatory disturbance-related diseases, but studies of the mechanisms underlying its protective action have mainly focused on the myocardium, whereas little research has been carried out in brain tissue following ischemia-reperfusion. We assessed the neuroprotective effects of salvianolate in a rat model of cerebral ischemia-reperfusion injury induced using the suture method. At onset and 24 and 48 hours after reperfusion, rats were intraperitoneally injected with salvianolate (18 mg/kg) or saline. Neurological deficit scores at 72 hours showed that the neurological functions of rats that had received salvianolate were significantly better than those of the rats that had received saline. 2,3,5-Triphenyltetrazolium chloride was used to stain cerebral tissue to determine the extent of the infarct area. A significantly smaller infarct area and a significantly lower number of apoptotic cells were observed after treatment with salvianolate compared with the saline treatment. Expression of heat shock protein 22 and phosphorylated protein kinase B in ischemic brain tissue was significantly greater in rats treated with salvianolate compared with rats treated with saline. Our findings suggest that salvianolate provides neuroprotective effects against cerebral ischemia-reperfusion injury by upregulating heat shock protein 22 and phosphorylated protein kinase B expression.

Overexpression of heat shock protein 22 inhibits the growth of hematopoietic malignant tumor cells / 白血病·淋巴瘤

Objective To investigate the effects of overexpression of heat shock protein 22(HSP22) in hematopoietic malignant tumor cell lines.Methods A lentiviral system was used to mediate transduction of HSP22 complementary DNA-containing expression vector or empty vector into K562 and Namalwa cells.The transduction effeciency was tested by fluorescence microscope scan and flow cytometry.Semi-quantitative RT-PCR and Western blot were used to identify the expression levels of HSP22 mRNA and protein.Growth curve analysis,cell cycle analysis,colony-forming assay,tumor growth in nude mice and apoptosis analysis were used to evaluate the role of HSP22 in K562 and Namalwa cells.Results Lentivector expression systemmediated delivery of HSP22 into K562 and Namalwa cells can inhibit colony forming of K562 and Namalwa cells,the average numbers of colonies per well were 108,72,125 and 80 for K562-V,K562-H,Namalwa-V and Namalwa-H respectively (P =0.000 16 and 0.000 37 for K562 and Namalwa respectively).HSP22 transduction can also inhibit proliferation of Namalwa cells in vitro (P =0.015,0.042 and 0.048 for day 5,6 and 7 respectively) and K562 cells in vivo (P =0.022 for day 21).No significant difference in cell cycle and apoptosis was found in K562 and Namalwa cells compared with controls (all P ＞ 0.05).Conclusion Overexpression of HSP22 could inhibit the growth of hematopoietic malignant tumor cell lines K562 and Namalwa.

Effects of decitabine on heat-shock protein 22 expression in malignant hematopoietic cells / 白血病·淋巴瘤

Objective To investigate the effects and possible mechanisms of decitabine on heat-shock protein 22 (HSP22) expression in hematopoietic tumor cell lines and bone marrow samples from patients with hematopoietic tumor.Methods The expression of HSP22 in 13 hematopoietic tumor cell lines,20 primary patients' samples and 10 normal donor' samples were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR).After HSP22 induction with a demethylating agent decitabine (2 μmol/L),the methylation of the HSP22 promoters in hematopoietic tumor cell lines,healthy donors and bone marrow samples from patients with hematopoietic tumor were detected by methylation specific PCR (MSP).Results Expression of HSP22 was not detected in 13 hematopoietic tumor cell lines,20 primary patients' samples or 10 healthy donors' samples.Decitabine can induce the expression of HSP22 in hematopoietic tumor cell lines and bone marrow samples from patients with hematopoietic tumor.Decitabine can maintain partially demethylation of HSP22 promoters in hematopoietic tumor cell lines.HSP22 promoters were highly methylated in BMMC of the healthy donors and patients with hcmatopoictic tumor.Conclusion Decitabine can induce the expression of HSP22 in hematopoietic tumor cells partly by demethylation of HSP22 promoters.