Nondamaging Retinal Laser Therapy: Rationale and Applications to the Macula

PURPOSE

Retinal photocoagulation and nondamaging laser therapy are used for treatment of macular disorders, without understanding of the response mechanism and with no rationale for dosimetry. To establish a proper titration algorithm, we measured the range of tissue response and damage threshold. We then evaluated safety and efficacy of nondamaging retinal therapy (NRT) based on this algorithm for chronic central serous chorioretinopathy (CSCR) and macular telangiectasia (MacTel).

METHODS

Retinal response to laser treatment below damage threshold was assessed in pigmented rabbits by expression of the heat shock protein HSP70 and glial fibrillary acidic protein (GFAP). Energy was adjusted relative to visible titration using the Endpoint Management (EpM) algorithm. In clinical studies, 21 eyes with CSCR and 10 eyes with MacTel were treated at 30% EpM energy with high spot density (0.25-diameter spacing). Visual acuity, retinal and choroidal thickness, and subretinal fluid were monitored for 1 year.

RESULTS

At 25% EpM energy and higher, HSP70 was expressed acutely in RPE, and GFAP upregulation in Müller cells was observed at 1 month. Damage appeared starting at 40% setting. Subretinal fluid resolved completely in 81% and partially in 19% of the CSCR patients, and visual acuity improved by 12 ± 3 letters. Lacunae in the majority of MacTel patients decreased while preserving the retinal thickness, and vision improved by 10 letters.

CONCLUSIONS

Heat shock protein expression in response to hyperthermia helps define the therapeutic window for NRT. Lack of tissue damage enables high-density treatment to boost clinical efficacy, therapy in the fovea, and retreatments to manage chronic diseases.

Heat exposure induces tissue stress in heat-intolerant, but not heat-tolerant, mice

We investigated the association of systemic and local tissue stress responses with heat-tolerant (TOL) levels in mice. Thirty-eight mice were assigned into control and three heat exposure groups-TOL, moderately tolerant, and intolerant (INT), based on their overall thermal responses. Real-time core temperature, blood pressure, and heart rate (HR) were assessed during heat exposure (39.5 °C) under conscious condition. Tissue samples were collected 18-22 h following heat exposure. INT mice had significantly higher peak mean arterial pressure and HR than TOL mice during heat exposure. Plasma corticosterone levels were significantly higher in INT than in control mice. No significant changes in plasma cytokines or markers of oxidative status were observed. INT mice showed significant increases in HSP72 and HSP90 protein and mRNA levels in liver, heart, and gastrocnemius muscles compared to TOL and control mice. In contrast, INT mice had significantly lower heat shock factor 1 and glucocorticoid receptor protein and mRNA levels in these tissues than TOL and control mice. These results indicate that acute heat exposure induces stress responses in various tissues of INT mice, but not TOL mice. Upregulation of stress proteins by acute heat exposure involves both transcriptional and translational pathways.

Anandamide enhances expression of heat shock protein 72 to protect against ischemia-reperfusion injury in rat heart

Anandamide (AEA), one of endocannabinoids, has been reported to exhibit a cardioprotective ability to limit the damage produced by ischemia-reperfusion injury. AEA reportedly enhanced heat shock protein 72 (HSP72) and HSP25 expression in lungs to protect against lung inflammation. This study tested the hypothesis that intravenously injected AEA would induce HSP72 in the heart and thus render cardioprotection against ischemia-reperfusion injury in rats. Cardiac expression of HSPs was quantitatively evaluated in rats by Western blot analysis. That intravenously injected AEA 1 mg/kg in vivo induced expression of HSP72, which peaked at 24 h after administration. The enhancement of HSP72 by AEA was blocked by cannabinoid 2 (CB(2)) receptor antagonist AM630, but not cannabinoid 1 (CB(1)) receptor antagonist AM251. Therefore, the rats were induced with a 30-min coronary occlusion followed by a 120-min reperfusion in vivo at 24 h after administration of drugs or vehicle, and then the infarct size was measured. AEA reduced myocardial infarct size compared to control group. Pretreatment with AM630 but not AM251 abolished the infarct size-limiting effect of AEA. Further study demonstrated pretreatment with phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin, Akt inhibitor MK-2206 and AM630 attenuated phosphorylation of Akt and AEA-induced HSP72 expression. The results suggest that AEA is cardioprotective against ischemia-reperfusion insult through its induction of HSP72, which might be mediated by the PI3K/Akt signaling pathway. These effects were mediated by CB(2) but not CB(1) receptors.

HSP27 expression in primary colorectal cancers is dependent on mutation of KRAS and PI3K/AKT activation status and is independent of TP53

Colorectal adenomas display features of senescence, but these are often lost upon progression to carcinoma, indicating that oncogene induced senescence (OIS) could be a roadblock in colorectal cancer (CRC) development. Heat shock proteins (HSPs) have been implicated in the prognosis of CRC and HSP based therapy is a current interest for drug development. Recent cell culture studies have suggested that in the absence of a TP53 mutation, OIS mediated by PI3K/AKT activation can be circumvented by high expression of HSPs. Furthermore, while PI3K/AKT activation and KRAS mutations are independent inducers of OIS, PI3K/AKT activation can suppress KRAS-induced OIS when both are present in cultured cells. As KRAS mutations, PI3K/AKT activation and TP53 mutations are all common features of CRC, it is possible that the requirement for HSP to inhibit OIS in CRC is dependent on the mutation spectrum of a tumour. However, work on HSP that utilised mutation profiled human tumour tissues has been limited. Here, we characterised the expression of two major HSP proteins (HSP27 and 72) by immunohistochemistry (IHC), the mutation status of TP53, KRAS and PIK3CA genes by direct sequencing and the activation status of AKT by IHC in a cohort of unselected primary CRC (n=74). We compare our data with findings generated from cell-based studies. Expression of HSP27 and HSP72 was correlated to clinicopathological and survival data but no significant association was found. We also established the mutation status of TP53, KRAS and PIK3CA genes and the activation status of AKT in our CRC panel. We did not detect any associations between HSP27 or HSP72 expression with TP53 mutation status. However, HSP27 expression in CRCs was strongly associated with the co-presence of wildtype KRAS and activated PI3K/AKT (p=0.004), indicating a possible role of HSP27 in overcoming PI3K/AKT induced OIS in tumours. Our studies suggest a role for using archival tissues in validating hypotheses generated from cell culture based investigations.

Human hepatoma cell line (HepG2) cellular response to hypothermic stress with recovery. Induction of Hsp70, Hsp60 and Hsf1 expression

The cell response of human HepG2 cells exposed to hypothermia with rewarming was analyzed. Ultrastructural findings in hypothermic stressed cells showed swollen mitochondria, dispersed chromatin, vacuoles and ring-shape nucleolar reorganization. These changes were coupled with significative differences in the induction of Hsp60, inducible Hsp70 and monomeric Hsfl in all treated samples, but not in Hsc 70 expression. Cellular response to hypothermia could be associated with the synergistic induction of Hsp expression.

The relationship between heat shock protein 72 expression in skeletal muscle and insulin sensitivity is dependent on adiposity

Decreased gene expression of heat shock protein 72 (HSP72) in skeletal muscle is associated with insulin resistance in humans. We aimed to determine whether HSP72 protein expression in insulin-sensitive tissues is related to criterion standard measures of adiposity and insulin resistance in a young healthy human population free of hyperglycemia. Healthy participants (N = 17; age, 30 ± 3 years) underwent measurement of body composition (dual-energy x-ray absorptiometry), a maximum aerobic capacity test (VO(2max)), an oral glucose tolerance test, and a hyperinsulinemic-euglycemic clamp (M) to access insulin sensitivity. Skeletal muscle and subcutaneous adipose tissue biopsies were obtained by percutaneous needle biopsy. HSP72 protein expression in skeletal muscle was inversely related to percentage body fat (r = -0.54, P < .05) and remained significant after adjustment for age and sex (P < .05). Insulin sensitivity was also related to HSP72 protein expression in skeletal muscle (r = 0.52, P < .05); however, this relationship disappeared after adjustment for percentage body fat (P = .2). In adipose tissue, HSP72 protein expression was not related to adiposity or insulin sensitivity. Physical activity and aerobic fitness did not show any association with HSP72 protein expression in either tissue studied. A lower expression of HSP72 protein in human skeletal muscle was associated with increased adiposity and decreased insulin sensitivity in healthy individuals. These findings are consistent with rodent data suggesting that HSP72 stimulates fat oxidation with consequent reduction in fat storage and adiposity.

Heat stress elicits different responses in peripheral blood mononuclear cells from Brown Swiss and Holstein cows

This study was undertaken to assess whether peripheral blood mononuclear cells (PBMC) isolated from Brown Swiss (Br) and Holstein (Ho) cows and stimulated with concanavalin A differ in response to chronic exposure to incubation temperatures simulating conditions of hyperthermia. Five multiparous Br and 5 Ho cows were utilized as blood donors. Peripheral blood mononuclear cells were subjected for 65 h to each of 5 treatments (T). Cells were exposed to 39 degrees C continuously (T39) and three 13-h cycles at 40 (T40), 41 (T41), 42 (T42) or 43 degrees C (T43), respectively, which were interspersed with two 13-h cycles at 39 degrees C. Treatment T39 was adopted to mimic normothermia; T40, T41, T42, and T43 mimicked conditions of more severe hyperthermia alternating with normothermia. Measures evaluated at the end of the incubation period were proliferative response (DNA synthesis), intracellular reactive oxygen species (ROS) concentrations, and mRNA abundance of the 72-kDa heat-shock protein (Hsp72). In Br cows, DNA synthesis began to decline when PBMC were repeatedly exposed to 41 degrees C (-22%), whereas DNA synthesis in cells isolated from Ho cows did not begin to decline until 42 degrees C (-40%). Furthermore, under T41 and T42, DNA synthesis from Br cows was lower than in Ho(-24 and -54%, respectively). In both breeds, increased incubation temperatures caused a reduction of intracellular ROS (from -39.6 and -69.7%). Increase in incubation temperatures enhanced Hsp72 mRNA levels only in PBMC isolated from Br cows. The Hsp72 mRNA in Br cows increased significantly under T41 and T43 compared with T39. In both breeds, DNA synthesis was positively and negatively correlated with intracellular ROS and Hsp72 mRNA abundance, respectively (r = 0.85 and r = -0.70, respectively). Results indicated that PBMC from Br cows are less tolerant to chronic heat exposure than those from Ho cows, and that the lower tolerance is associated with higher expression of Hsp72, suggesting that the same level of hyperthermia may be associated with a differential decline of immune function in the 2 breeds.

Nitric oxide induces heat shock protein 72 production and delayed protection against myocardial ischemia in rabbits via activating protein kinase C

BACKGROUND

Nitric oxide (NO) is a biologically active molecule which has been reported to protect the heart against ischemia and reperfusion injury in different species. This study aimed to test the hypothesis that nitric oxide may induce the expression of heat shock protein 72 (HSP72) which may protect the heart against ischemia.

METHODS

Rabbits were given intravenous saline or S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide donor, or Zaprinast, an inhibitor of cyclic guanosine monophosphate (GMP)-phosphodiesterase, which may increase myocardial cyclic GMP content. Twenty-four hours later, the rabbits were either sampled to measure HSP72, or induced with a 30-minute coronary occlusion followed by a 120-minute reperfusion, and then the infarct size was measured. Meanwhile, chelerythrine (CHE, an inhibitor of protein kinase C) was given intravenously 5 minutes before SNAP injection and the effect on HSP72 expression and infarct size was determined.

RESULTS

Twenty-four hours after pretreatment, immunoblotting showed HSP72 expression increased in the SNAP group compared with control groups, and this was blocked by CHE. Myocardial infarct size in the SNAP group was smaller than that of the control group ((32.4 +/- 5.8)% vs (51.1 +/- 4.7)%, P < 0.05). Pretreated with CHE abolished the infarct size-limiting effect of SNAP ((46.0 +/- 5.1)%). Pretreatment with Zaprinast neither induced HSP72 expression nor reduced infarct size ((55.4 +/- 5.4)%).

CONCLUSION

NO induced HSP72 expression and a delayed protection to the heart via the activities of protein kinase C by a cyclic GMP-independent pathway.

Rapamycin conditionally inhibits Hsp90 but not Hsp70 mRNA translation in Drosophila: implications for the mechanisms of Hsp mRNA translation

Rapamycin inhibits the activity of the target of rapamycin (TOR)-dependent signaling pathway, which has been characterized as one dedicated to translational regulation through modulating cap-dependent translation, involving eIF4E binding protein (eIF4E-BP) or 4E-BP. Results show that rapamycin strongly inhibits global translation in Drosophila cells. However, Hsp70 mRNA translation is virtually unaffected by rapamycin treatment, whereas Hsp90 mRNA translation is strongly inhibited, at normal growth temperature. Intriguingly, during heat shock Hsp90 mRNA becomes significantly less sensitive to rapamycin-mediated inhibition, suggesting the pathway for Hsp90 mRNA translation is altered during heat shock. Reporter mRNAs containing the Hsp90 or Hsp70 mRNAs' 5' untranslated region recapitulate these rapamycin-dependent translational characteristics, indicating this region regulates rapamycin-dependent translational sensitivity as well as heat shock preferential translation. Surprisingly, rapamycin-mediated inhibition of Hsp90 mRNA translation at normal growth temperature is not caused by 4E-BP-mediated inhibition of cap-dependent translation. Indeed, no evidence for rapamycin-mediated impaired eIF4E function is observed. These results support the proposal that preferential translation of different Hsp mRNA utilizes distinct translation mechanisms, even within a single species.

Nuclear heat shock protein 72 as a negative regulator of oxidative stress (hydrogen peroxide)-induced HMGB1 cytoplasmic translocation and release

In response to inflammatory stimuli (e.g., endotoxin, proinflammatory cytokines) or oxidative stress, macrophages actively release a ubiquitous nuclear protein, high-mobility group box 1 (HMGB1), to sustain an inflammatory response to infection or injury. In this study, we demonstrated mild heat shock (e.g., 42.5 degrees C, 1 h), or enhanced expression of heat shock protein (Hsp) 72 (by gene transfection) similarly rendered macrophages resistant to oxidative stress-induced HMGB1 cytoplasmic translocation and release. In response to oxidative stress, cytoplasmic Hsp72 translocated to the nucleus, where it interacted with nuclear proteins including HMGB1. Genetic deletion of the nuclear localization sequence (NLS) or the peptide binding domain (PBD) from Hsp72 abolished oxidative stress-induced nuclear translocation of Hsp72-DeltaNLS (but not Hsp72-DeltaPBD), and prevented oxidative stress-induced Hsp72-DeltaPBD-HMGB1 interaction in the nucleus. Furthermore, impairment of Hsp72-DeltaNLS nuclear translocation, or Hsp72-DeltaPBD-HMGB1 interaction in the nucleus, abrogated Hsp72-mediated suppression of HMGB1 cytoplasmic translocation and release. Taken together, these experimental data support a novel role for nuclear Hsp72 as a negative regulator of oxidative stress-induced HMGB1 cytoplasmic translocation and release.

The short-term effects of electrosurgical ablation on proinflammatory mediator production by intervertebral disc cells in tissue culture

BACKGROUND CONTEXT

Percutaneous discectomy can be performed by a variety of methods. One method, electrosurgical ablation, has been shown in a chronic animal model to alter the expression of inflammatory cytokines in degenerated discs.

PURPOSE

To determine whether electrosurgical ablation has an acute direct effect on proinflammatory mediator production by disc cells.

STUDY DESIGN

A short-term in vitro study using normal and interleukin (IL)-1alpha stimulated porcine disc cells cultured in alginate gel to evaluate the biochemical effects of electrosurgical ablation.

METHODS

Porcine annulus and nucleus cells were embedded into alginate gels and cultured using control culture media or IL-1alpha-treated media for 6 days before ablation treatment. Treated gels were ablated by using a radiofrequency-based electrosurgical device for 5 seconds and cultured an additional 3 or 6 days. IL-1beta, IL-6, IL-8, tumor necrosis factor alpha (TNF-alpha), prostaglandin E2 (PGE2), nitric oxide (NO), and heat shock protein-70 (Hsp70) levels in culture medium were measured. Levels were normalized to DNA and compared between ablated and shams.

RESULTS

For normal annulus cells, there were no significant changes in cytokine levels between ablation and sham groups. For normal nucleus cells, ablation produced significantly greater levels of IL-8 at 3 days and 6 days, Hsp70 at 3 days but not 6 days, and NO at 6 days. PGE2 was also increased at 3 days and 6 days but not significantly. For IL-1-stimulated annulus cells, IL-6 and NO in the ablation group were decreased at 3 days relative to the control group. However, IL-6, IL-8, PGE2, and Hsp70 were significantly increased in the 6-day ablation group. For degenerated nucleus cells, IL-6, IL-8, and TNF-alpha were significantly decreased in the ablation group at both 3 days and 6 days. Ablation resulted in reduced PGE2 at 3 days but not 6 and reduced Hsp70 and NO at 6 days.

CONCLUSIONS

The results show that electrosurgical ablation has an acute direct effect on proinflammatory mediator production by disc cells. The effect produced depends on disc cell phenotype, the mediator, and time. These direct biologic effects may be a mechanism of pain relief after percutaneous discectomy using electrosurgical ablation. However, the measured responses are limited to the short-term (1 week), and the existence of a prolonged effect remains to be determined.

Geranylgeranylaceton induces heat shock protein 72 in skeletal muscle cells

Effects of an antiulcer drug, geranylgeranylaceton (GGA), and/or heat-stress on 72 kDa heat shock protein (HSP72) expression and protein content in cultured skeletal muscle cells were studied. Mouse skeletal muscle cells (C(2)C(12)) were subjected to either 1) control (cultured at 37 degrees C without GGA), 2) GGA administration (10(-11) - 10(-8) M), 3) heat-stress at 41 degrees C for 60 min, or 4) GGA administration combined with heat-stress. Expression of HSP72 was up-regulated by GGA administration. Heat-stress further enhanced the GGA-related up-regulation of HSP72. Administration of GGA caused an increase of muscular protein content as a dose-dependent manner. Protein synthesis was also stimulated by heat-stress alone in myotubes. It was suggested that GGA stimulates the differentiation of myoblasts and protein synthesis. These observations may also suggest that the administration of GGA could be one of the useful tools to gain muscular mass not only in athletes, but also in patients during rehabilitation.

Heat Shock Protein Expression in Rat Skeletal Muscle After Repeated Applications of Pulsed and Continuous Ultrasound

OBJECTIVE

To determine whether repeated ultrasound treatments are capable of increasing the expression of heat shock protein (HSP) 72 and HSP 25 in rat skeletal muscles.

DESIGN

In vivo, experimental, controlled study.

SETTING

Animal laboratory.

ANIMALS

Male Sprague-Dawley rats (n=9).

INTERVENTIONS

Ultrasound (1MHz, 15 min, 2.0 cm2 transducer) continuous at 1.0 W/cm2 spatial average temporal average intensity (CONTUS) or pulsed at 2.0 W/cm2 spatial average temporal peak intensity 50% duty cycle (PULS50) was applied on 4 consecutive days to the lower leg muscles of 1 hindlimb in each rat (n=9).

MAIN OUTCOME MEASURES

Twenty-four hours after the final ultrasound application, hindlimb muscles were removed, weighed, and assessed for HSP 72 and HSP 25 content by Western blotting. Bands from blots were quantified and data were assessed using t tests (alpha=.05).

RESULTS

Ultrasound did not affect core or contralateral hindlimb muscle temperature. Average muscle temperatures during the final day ultrasound treatments were 38.71 degrees +/-0.30 degrees C when using PULS50 and 38.16 degrees +/-0.57 degrees C when using CONTUS. PULS50 significantly increased HSP 25 content in the plantaris and soleus muscles and HSP 72 content in the plantaris muscles. CONTUS significantly increased HSP 72 content in the white gastrocnemius muscle.

CONCLUSIONS

HSPs can be induced in skeletal muscle when ultrasound is used on a repeated basis to treat soft tissue.

Expression of heat shock protein 72 in peritoneal leukocytes is induced by peritoneal dialysis

BACKGROUND

One of the main limitations of peritoneal dialysis (PD) is deterioration of functional and morphological characteristics of the peritoneum. This complication appears to be related to the low biocompatibility profile of PD fluids. Recently, induction of the heat shock protein (HSP) stress response was demonstrated in cultured human mesothelial cells exposed to PD fluid in vitro. We investigated whether expression of heat shock protein 72 (HSP-72) in peritoneal macrophages is induced upon exposure to PD fluid during continuous ambulatory PD.

METHODS

Peritoneal leukocytes were isolated from 4-hour dwell dialysate; peripheral blood mononuclear cells (PBMC) and peripheral blood monocytes isolated from the same patients were used as a control. In separate experiments, PBMC from healthy individuals were exposed in vitro to different PD fluids or to culture media. Expression of HSP-72 was assessed by Western immunoblotting, flow cytometry, and reverse-transcription polymerase chain reaction analysis.

RESULTS

Macrophages and leukocytes isolated from dialysis effluent expressed significantly increased HSP-72 and mRNA levels compared to blood monocytes and PBMC of the same patients. In vitro exposure of PBMC to fresh PD fluids resulted in significantly higher expression of HSP-72 compared to those incubated in culture medium. PBMC exposed in vitro to standard lactate-buffered dialysis fluids also expressed significantly more HSP-72 compared to cells exposed to bicarbonate/lactate-buffered fluids.

CONCLUSION

Our results indicate that exposure to PD fluids during dialysis triggers a shock response in peritoneal cells, which is manifested by significantly increased HSP-72 expression at both protein and mRNA levels. Analysis of this protein expression in peritoneal macrophages could be a new, convenient, and relevant way to assess the biocompatibility of PD fluids ex vivo.

Heat stress attenuates ATP-depletion and pH-decrease during cardioplegic arrest

BACKGROUND

The capacity of heat stress induction to improve myocardial tolerance against ischemia is well known. We investigated cardiac energy metabolism after hsp 72(+)/73(+) induction in isolated perfused neonatal rabbit hearts subjected to prolonged cold cardioplegic ischemia.

METHODS

Hearts from neonatal rabbits were excised, isolated perfused and arrested by 2-h cold cardioplegic ischemia. Rectal temperature of eight neonatal rabbits was raised to 42.0 to 42.5 degrees C for heat shock protein expression in a whole body water bath for 15 min before the onset of arrest. Another set of eight rabbits without hyperthermia pretreatment served as control. Recovery of left ventricle function was assessed by aortic flow, cardiac output, and max dP/dt. Status of high-energy phosphates was measured by (31)phosphorus nuclear magnetic resonance-spectroscopy.

RESULTS

Immunoblot analysis revealed clear hsp 72+/73+ induction after a brief period of systemic hyperthermia. Heat stress pretreatment resulted in a better recovery of left ventricular function (aortic flow and cardiac output improvement P < 0.05, max dP/dt P < 0.01) than in controls at 60 min after reperfusion. During ischemia and reperfusion, myocardial energy metabolism was better preserved in hearts after hsp induction as a consequence of increased gamma-, alpha-, and beta-ATP as well as phosphocreatine-values over controls. The ischemia-induced pH-decrease was attenuated.

CONCLUSION

These data contribute to the evidence of heat stress mediated beneficial effects on functional myocardial recovery and improved cardiac energy metabolism after prolonged cold cardioplegic ischemia. More importantly, the attenuation of ischemic pH reduction and better restoration suggest an involvement of mitochondrial membrane potential alterations.

Preoperative unstable angina causes venous adaptation to surgical graft injury

Ischemic preconditioning may provide a systemic organ protection, evident as the phenomenon known as remote preconditioning. Unstable angina may be a clinical analogue to ischemic preconditioning. Vein graft harvesting induces inflammation of the graft wall. We hypothesized that preoperative unstable angina preconditions vein grafts and reduces the inflammatory response to graft harvesting. Consecutive patients with stable or unstable angina undergoing open heart surgery (n = 12 in each group) were studied. Saphenous vein biopsies were collected at the start of graft harvesting, and when the last proximal anastomosis to the aorta was finished (average 112 minutes later). Gene expression of inflammatory mediators (tumor necrosis factor alpha, interleukin-1beta (IL-1beta), E-selectin (CD62E), intercellular leukocyte adhesion molecule 1, inducible nitric oxide synthase, endothelin-1) increased after surgical handling (semiquantitative RT-PCR). In vein grafts from unstable patients the increase was attenuated for Il-1beta (p < 0.004) and CD62E (p < 0.001). In stable patients the protein expression of IkappaBalpha and heat shock protein72 was reduced by surgical handling (p < 0.04), but was not influenced in unstable patients (immunoblotting). In vitro relaxation to acetylcholine was enhanced, and contractions to phenylephrine and endothelin-1 were attenuated in veins rings from unstable patients (p < 0.003). In conclusion, surgical handling of vein grafts induces inflammation of the vessel wall. This response was reduced in grafts from patients with unstable angina, indicating a possible systemic preconditioning-like effect of acute coronary syndromes.

Functional alterations in macrophages after hypoxia selection

Regions of low oxygen tension are common features of inflamed and infected tissues and provide physiologic selective pressure for the expansion of cells with enhanced hypoxia tolerance. The aim of this study was to investigate whether macrophages resistant to death induced by hypoxia were accompanied by functional alterations. A mouse macrophage cell line (J774 cells) was used to obtain subpopulations of death-resistant macrophages induced by long-term exposure to severe hypoxia (<1% O(2)). The results indicated that exposing J774 macrophages to periods of severe hypoxia results in the selection of cells with phenotypes associated with the modulation of heat-shock protein 70 kDa (HSP70) expression, tumor necrosis factor-alpha (TNF-alpha), and nitric oxide (NO) production and reduced susceptibility to parasite Leishmania infection. Thus, we suggest that hypoxia-selected macrophages may influence the outcome of inflammation and infection.

Increased temperature, not cardiac load, activates heat shock transcription factor 1 and heat shock protein 72 expression in the heart

The expression of myocardial heat shock protein 72 (HSP72) postexercise is initiated by the activation of heat shock transcription factor 1 (HSF1). However, it remains unknown which physiological stimuli govern myocardial HSF1 activation during exercise. These experiments tested the hypothesis that thermal stress and mechanical load, concomitant with simulated exercise, provide independent stimuli for HSF1 activation and ensuing cardiac HSP72 gene expression. To elucidate the independent roles of increased temperature and cardiac workload in the exercise-mediated upregulation of left-ventricular HSP72, hearts from adult male Sprague-Dawley rats were randomly assigned to one of five simulated exercise conditions. Upon reaching a surgical plane of anesthesia, each experimental heart was isolated and perfused using an in vitro working heart model, while independently varying temperatures (i.e., 37°C vs. 40°C) and cardiac workloads (i.e., low preload and afterload vs. high preload and afterload) to mimic exercise responses. Results indicate that hyperthermia, independent of cardiac workload, promoted an increase in nuclear translocation and phosphorylation of HSF1 compared with normothermic left ventricles. Similarly, hyperthermia, independent of workload, resulted in significant increases in cardiac levels of HSP72 mRNA. Collectively, these data suggest that HSF1 activation and HSP72 gene transcriptional competence during simulated exercise are linked to elevated heart temperature and are not a direct function of increased cardiac workload.

Heat stress facilitates the regeneration of injured skeletal muscle in rats

BACKGROUND

Skeletal muscle stem cells, so-called muscle satellite cells, are responsible for the repair and the regeneration of adult skeletal muscle tissues. Heat stress can facilitate the proliferation and the differentiation of myoblasts in vitro and can enhance their proliferative potential, which may stimulate the regrowth of atrophied skeletal muscle. The purpose of this study was to investigate the effect of heat stress on the regeneration of skeletal muscle injury induced by cardiotoxin.

METHODS

Male Wistar rats, aged 7 weeks, were randomly divided into six groups: a nonheated control group that received a physiological saline injection, a group heat stressed before physiological saline injection, a group heat stressed after physiological saline injection, a group injected with cardiotoxin without heat stress, a group heat stressed before cardiotoxin injection, and a group heat stressed after cardiotoxin injection (25 in each group). To initiate muscle injury and regeneration, 0.5 ml of 10 microM cardiotoxin was injected into the left tibialis anterior muscle. Conscious rats in some groups were exposed to environmental heat stress (41 degrees C for 60 min) in a heat chamber 24 h before or immediately after cardiotoxin or physiological saline injection. The heating protocol in the present study causes an increase in the colonic temperature to 41 degrees C. The left tibialis anterior muscles were dissected 1, 3, 7, 14, and 28 days after injection of cardiotoxin or physiological saline.

RESULTS

The wet weight and water content of muscles increased 1 day after cardiotoxin injection regardless of the application of heat stress, but normalized after 7-14 days. The muscle protein content in control rats had increased 7 days after heat stress. Although the muscle protein content decreased on cardiotoxin injection, heat stress caused a significant recovery in protein level. Expression of heat shock protein 72 (HSP72) and the number of Pax7-positive nuclei decreased after cardiotoxin injection but increased on the application of heat stress in both normal control and cardiotoxin-injected groups.

CONCLUSIONS

Heat stress stimulated not only the proliferation of satellite cells but also protein synthesis during the regeneration of injured skeletal muscle. It is thus strongly suggested that the heating of injured skeletal muscle may facilitate recovery. There was no direct relationship between the level of HSP72 expression and muscle protein content, suggesting that HSP72 expression may not be the key signal for protein synthesis in the necrosis-regeneration process.

Zinc l-carnosine protects colonic mucosal injury through induction of heat shock protein 72 and suppression of NF-κB activation

In this study, we investigated the effects of zinc L-carnosine, an anti-ulcer drug, on acetic acid-induced colonic mucosal injury and the correlation of these effects with expression of 72-kDa heat shock proteins (HSP72) and nuclear factor kappa B (NF-kappaB) activation in rat colonic mucosa in vivo. After intrarectal administration of zinc L-carnosine, the rats received intrarectal infusion of 5% acetic acid (1 ml). The colonic mucosal damage was evaluated by macroscopic assessments 24 h after the intrarectal infusion of acetic acid. Expression of HSP72 in rat colonic mucosa was evaluated by Western blot analysis before and after zinc L-carnosine administration. NF-kappaB activation was evaluated by electrophoretic mobility shift assays (EMSA). Zinc L-carnosine inhibited visible damage in rat colonic mucosa by acetic acid. Expression of HSP72 was significantly increased at 6 h after zinc L-carnosine administration. Furthermore, NF-kappaB activation in colonic mucosa was suppressed 6 h after zinc L-carnosine treatment. These results suggested that zinc L-carnosine protects the colonic mucosa against acetic acid by induction of HSP72 and suppression of NF-kappaB activation and zinc L-carnosine may be a novel therapeutic agent for the therapy of inflammatory bowel disease.

Basal forebrain cholinergic lesions reduce heat shock protein 72 response but not pathology induced by the NMDA antagonist MK-801 in the rat cingulate cortex

Non-competitive N-methyl-D-aspartate (NMDA) antagonists, in addition to their neuroprotective potential, possess neurotoxic properties and induce seizures and psychosis. MK-801 induces cytoplasmic vacuoles and heat shock protein in pyramidal neurones in the rodent posterior cingulate and retrosplenial cortex. The mechanism of this neurotoxicity is unclear, involving many neurotransmitter systems. The aim of this study was to investigate the role of cholinergic pathways from the nucleus basalis of Meynert in mediating MK-801-induced neurotoxicity. Cholinergic projections from the nucleus basalis of Meynert were lesioned by focal injection of 192-IgG-saporin (80 ng), which after 7 days reduced the number of cholinergic cell bodies by 70% in the lesioned nucleus compared to the uninjected nucleus. Following a unilateral cholinergic lesion, MK-801 (5 mg/kg s.c.) induced expression of hsp72 mRNA (6 h) and HSP72 protein immunoreactivity (24 h) was reduced by 42 and 60%, respectively in the ipsilateral compared to the contralateral posterior cingulate. Despite this apparent protective effect, the unilateral cholinergic lesion did not affect the degree of neuronal vacuolation (6 h), necrosis (24 h) or the large and prolonged increase in cerebral blood flow which occurred over the first 9h following MK-801 administration. These results demonstrate that cholinergic neurones in the nucleus basalis of Meynert play an important role in the heat shock response to NMDA antagonist-induced neurotoxicity but also reveal an unexpected divergence between the heat shock response and the pathophysiological response. This suggests that other cholinergic pathways or non-cholinergic mechanisms are responsible for the pathological changes induced by MK-801.

[Relationship between dust exposure and chronic obstructive pulmonary diseases and heat shock protein 72 and 73 in lymphocytes among coal miners]

OBJECTIVE

To assess the expression of Hsp72 and Hsp73 in chronic obstructive pulmonary disease (COPD) and to evaluate their roles in damage from coal dust exposure.

METHODS

A case control study of 50 coal miners suffering from COPD and 50 healthy coal miners were selected from one coal mine. The levels of Hsp72 and Hsp73 in peripheral blood lymphocytes were determined by flow cytometry for all subjects.

RESULTS

(1) The expression of basic Hsp72 of peripheral blood lymphocytes for patients and controls was not different from that inducible expressed Hsp72 by 42 degrees C heat stress or by BPDE exposure. (2) The expression of Hsp72 in COPD patients (17.7 +/- 4.9) was significantly lower than that in healthy coal miners (22.6 +/- 10.0) (P < 0.01). On the other hand, the expression of Hsp73 in COPD patients (33.5 +/- 11.7) was higher than that in healthy coal miners (19.6 +/- 5.9) (P < 0.01). (3) A-positive relationship between the expression of Hsp72 and cumulative inhaling coal dust exposure was observed. No relationship was found between Hsp73 and cumulative inhaling coal dust exposure.

CONCLUSION

The decreased expressions of Hsp72 in peripheral blood lymphocytes of COPD coal miners.

[Preparation and identification of polyclonal antiserum against heat shock protein 72]

OBJECTIVE

To express fusion protein of histamine (His) and human heat shock protein 72 (hHSP72) in Escherichia coli (E. coli), and to prepare hHSP72 antiserum in rabbit.

METHODS

hHSP72 gene was inserted into pPROEX-1. The recombinant vector was identified by restriction endonuclease digestion analysis and sequence. Fusion protein His-hHSP72 was expressed in E. coli under isopropyl-beta-D-thiogalactoside (IPTG) induction. The rabbit antibody against His-hHSP72 was prepared by using purified His-hHSP72 protein as immunogen, and the specificity and sensitivity of polyclonal antibody were identified by Western blot.

RESULTS

The restriction endonuclease digestion analysis of recombinant plasmid and sequence demonstrated that the hHSP72 gene had been exactly inserted into pPROEX-1. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the relative molecular mass of the fusion protein was about 73 ku. Western blot result proved that the rabbit polyclonal antiserum could fuse with over 20 ng hHSP72 protein when diluted to 1:100,000.

CONCLUSION

The polyclonal antibody against hHSP72 can be prepared in E. coli, it is a new reagent with high specificity and sensitivity for the research of hHSP72.

Expression of HSP72 in the gastric mucosa is regulated by gastric acid in rats-correlation of HSP72 expression with mucosal protection

BACKGROUND AND AIM

The real mechanism of adaptive cytoprotection in the gastric mucosa is not well established. In the present study, we investigated the effect of acid suppressing agents on a 72-kDa heat shock protein (HSP72) expression, which is known as endogenous cytoprotective factor, in the gastric mucosa. Also, the association of gastric mucosal protective function against HCl-challenge was compared between HSP72-induced and -reduced group.

MATERIALS AND METHODS

Expression of HSP72 was measured by Western blotting in the gastric mucosa before and after administration of famotidine or omeprazole. The gastric mucosal protective function against 0.6 N HCl was compared between control group and HSP72-reduced group. Also, the effect of increased expression of gastric HSP72 by additional administration of zinc sulfate or zinc L-carnosine, which is known as HSP72-inducer, on mucosal protective function was studied.

RESULTS

HSP72 expression in the gastric mucosa was reduced by acid suppressing agents. The lowest expression level of HSP72 was observed 12 h (famotidine, H2-receptor antagonist) or 48 h (omeprazole, proton pump inhibitor) after administration. The gastric mucosal protective ability against 0.6 N HCl was also reduced when HSP72 expression was decreased by famotidine or omeprazole. This phenomenon was reversed by HSP72 induction by additional administration of zinc derivatives.

CONCLUSION

Our results might indicate that the expression of HSP72 in the gastric mucosa is physiologically regulated by gastric acid, and that HSP72 induction could be important in view of mucosal protection especially when HSP72 expression is reduced by administration of acid suppressing agents such as proton pump inhibitor or H2 receptor antagonist.

Expression of COX-2 and hsp72 in peritoneal macrophages after an acute ochratoxin A treatment in mice

Ochratoxin A (OTA) is a secondary fungal metabolite produced by Aspergillus and Penicillium strains that elicits a broad spectrum of toxicological effects in animals and man. A single oral OTA administration (10 mg/kg) in mice induced after 24 h oxidative damage and polymorphonuclear leukocyte (PMN) infiltration in parenchymal organs. In fact, OTA treatment increased lipid peroxidation (via malondialdehyde formation) in kidney and liver and PMN accumulation in duodenum, as shown by myeloperoxidase activity. Following in vivo OTA treatment an increase of cyclooxygenase-2 and of heat shock protein 72 expression was evidenced in peritoneal macrophage lysates by Western blot. That OTA modulates these proteins involved in the inflammatory process indicates that the mycotoxin is able to activate immune cells. This study suggests that the oxidative stress, the neutrophil accumulation in parenchymal tissues and the modulation of inflammatory parameters in peritoneal macrophages induced by OTA are involved in its toxicity, and represent early events related to several aspects of OTA mycotoxicosis.

Stress proteins (Hsp72/73, Grp94) expression pattern in rat organs following metavanadate administration. Effect of green tea drinking

Expression pattern of heat shock proteins (Hsp) 72/73 and glucose regulated protein (Grp) 94 was studied in liver, kidney and testis of rats injected with sublethal doses of ammonium metavanadate (5 mg/kg/day). In addition, some batches of animals were given green tea decoction, known to be rich in anti-oxidative compounds, as sole beverage in order to evaluate its protective properties. In control animals, the stress proteins expression was found to be organ-dependent: anti-Grp94 antibody revealed two bands at 96 and 98 kDa in kidney and liver whereas the 98 kDa band only was found in testis; anti-Hsp72/73 antibody revealed that the constitutive Hsp73 was present in all organs whereas the inducible Hsp72 was only present in kidney and testis. In kidney of vanadium-treated rats, Hsp73 was over-expressed by about 50% whereas Hsp72 was down-regulated by 50-80%. No such effects were observed in liver and testis. In liver and kidney of vanadium-treated rats, Grp94 was over-expressed by 50% and 150% respectively whereas no change was found in testis. In rats given green tea as sole beverage, the 96 kDa protein expression level in liver was reduced both in controls and in vanadium-treated animals. However, green tea drinking failed to prevent the vanadium-induced Hsp72 under-expression in kidney of vanadium-treated rats.

Tubular stress proteins and nitric oxide synthase expression in rat kidney exposed to mercuric chloride and melatonin

Stress proteins such as HSP70 members (HSP72 and GRP75) and metallothionein (MT) protect the kidney against oxidative damage and harmful metals, whereas inducible nitric oxide synthase (iNOS) regulates tubular functions. A single dose of mercuric chloride (HgCl(2)) can cause acute renal failure in rats, its main target being the proximal tubule. Oxidative damage has been proposed as one of its pathogenic mechanisms. In this study we tested whether melatonin (MEL), a powerful antioxidant compound, is effective against HgCl(2) nephrotoxicity. Rats were treated with saline, HgCl(2) (3.5 mg/kg), MEL (5 mg/kg), and MEL + HgCl(2) and examined after 24 hr for HSP72, GRP75, MT, and iNOS by immunohistochemistry and immunoblotting. Tubular effects of the treatment were then characterized by ultrastructure. In the HgCl(2) group, all markers were overexpressed in convoluted proximal tubules and sometimes in distal tubules. In the MEL + HgCl(2) group, GRP75 and iNOS decreased in convoluted and straight proximal tubules, whereas HSP72 and MT persisted more than the saline and MEL-only groups. Tubular damage and mitochondrial morphometry were improved by MEL pretreatment. In conclusion, the beneficial effect of MEL against HgCl(2) nephrotoxicity was outlined morphologically and by the reduction of the tubular expression of stress proteins and iNOS. These markers could represent sensitive recovery index against mercury damage.

Increased expression of heat shock protein (HSP)72 in a human proximal tubular cell line (HK-2) with gentamicin-induced injury

Gentamicin (GM) has been widely used as an antibiotic and its nephrotoxicity has been recognized. However, the alternation of heat shock protein (HSP) 72 as an inductive protein in proximal tubular cells treated with GM is still unclear. In this study, GM cytotoxicity and its effect on the expression of HSP72 in human kidney proximal tubular (HK-2) cells were measured. HK-2 cells were incubated for 24 hr, 48 hr, 72 hr, and 96 hr with GM only and GM plus MnCl2, respectively. Cytotoxicity was determined by the release of lactate dehydrogenase (LDH). Activity of N-acetyl-beta-D-glucosaminidase (NAG) and effects of GM on oxidation in HK-2 cells were investigated by measurements of malondialdehyde (MDA) content and superoxide dismutase (SOD) activity, and the ability of viable cells to reduce a tetrazolium-based compound (MTT). The expression of HSP72 was measured by immunocytochemistry, Western blotting and RT-PCR. Cells were exposed to GM at a concentration of 100 microg/ml. After 24 hr MTT uptake decreased significantly and then gradually until 96 hr. LDH release increased time-dependently from 24 hr to 72 hr, but decreased at 96 hr compared with the data at 72 hr when cells were treated with GM only. Both results of NAG and SOD activities and results of MDA content were similar to that of the LDH release. The amount of HSP72 positive cells increased at 24 hr after exposure to GM up to 72 hr. HSP72 expression increased significantly from 24 hr, and reached its peak at 72 hr when cells were treated with GM only. Furthermore, the change of the HSP72 gene transcription was similar to the expression of HSP72. These results demonstrated that GM treatment could induce damage to HK-2 cells and that the expression of HSP72 increased when cells were injured by GM.

Phosphatidylinositol 3-kinase-dependent activation of akt, an essential signal for hyperthermia-induced heat-shock protein 72, is attenuated in streptozotocin-induced diabetic heart

We tested the hypothesis that phosphatidylinositol 3-kinase (PI 3-kinase)-dependent activation of Akt is essential for the expression of cardiac heat-shock protein 72 (HSP72) and that this pathway is impaired in the streptozotocin (STZ)-induced diabetic heart. STZ-induced male diabetic rats were treated with insulin (STZ-insulin group, n = 26) or vehicle (STZ-vehicle group, n = 61) for 3 weeks. Whole-body hyperthermia (43 degrees C for 20 min) was applied, and the heart was isolated 24 h later. Compared with control heart, hyperthermia-induced HSP72 expression and phosphorylation of Akt were attenuated in the STZ-vehicle heart. Pretreatment with wortmannin attenuated hyperthermia-induced HSP72 expression and phosphorylation of Akt. In isolated perfused heart experiments, the hyperthermia-treated STZ-vehicle heart showed poor left ventricular functional recovery during reperfusion after no-flow global ischemia compared with hyperthermia-treated control heart. Insulin treatment restored HSP72 expression and reperfusion-induced functional recovery. In cultured neonatal rat cardiomyocytes, hyperthermia-induced HSP72 expression was enhanced by insulin, together with tolerance against hypoxia-reoxygenation injury. Wortmannin and LY294002 inhibited hyperthermia-induced HSP72 expression and phosphorylation of Akt. Our results indicate that activation of Akt, in a PI 3-kinase-dependent manner, is essential for hyperthermia-induced HSP72 expression in association with cardioprotection, suggesting impairment of this signaling pathway in the STZ-induced diabetic heart, probably due to insulin deficiency.

Surface expression of HSP72 by LPS-stimulated neutrophils facilitates gammadeltaT cell-mediated killing

During inflammation and sepsis, accumulation of activated neutrophils causes lung tissue damage and organ failure. Effective clearance of neutrophils reduces the risk of organ failure; however, its mechanisms are poorly understood. Because lungs are rich in gammadeltaT cells, we investigated the physiological role of these cells in the protection of lung tissue from infiltrating neutrophils. In a mouse model of sepsis, we found that the lungs of survivors contained significantly higher numbers of gammadeltaT cells than those of mice that died from sepsis. The number of gammadeltaT cells correlated inversely with the number of neutrophils in the lungs and with the degree of lung tissue damage. LPS rapidly elicited the expression of heat shock protein (HSP) 72 on the surface of human neutrophils. Inhibitors of transcription, protein synthesis, and intracellular protein transport blocked HSP72 expression, indicating that de novo synthesis is required. gammadeltaT cells targeted and rapidly killed LPS-treated neutrophils through direct cell-to-cell contact. Pre-treatment with neutralizing antibodies to HSP72 diminished neutrophil killing. Our data indicate that HSP72 expression on the cell surface predisposes inflamed neutrophils to killing by gammadeltaT cells. This intercellular exchange may allow gammadeltaT cells to resolve inflammation and limit host tissue damage during sepsis.

[The protective effect of heat shock protein 72 by Doxorubicin in cold ischemia-reperfusion injury of the rat liver]

OBJECTIVE

To observe induction of heat shock reaction by pretreatment of Doxorubicin (DXR) in long-term cold preservation-reperfusion injury of the rat liver.

METHODS

The rats were administered intravenously by DXR at a dose of 1 mg/kg body weight in DXR group and by saline in control group. After 48 hours, the rat liver was perfused by using cold University of Wisconsin (UW) solutions and was preserved in UW solution at 4 degrees C for 48 hours. Recipient liver was perfused for 1 and 3 hours after orthotopic liver transplantation. Tumor necrosis factor-alpha (TNF-alpha) mRNA, cytokine-induced neutrophil chemoattractant (CINC) mRNA, macrophage inflammatory protein (MIP-2) mRNA was measured by RT-PCR and heat shock protein 72 (HSP72), nuclear factor-kappaB (NF-kappaB) by Western blot. The serum levels of TNF-alpha, CINC, MIP-2 by ELISA and AST were measured. The survival rate of 7 days was observed.

RESULTS

The expression of TNF-alpha mRNA, CINC mRNA and MIP-2 mRNA was stronger in control group than in DXR group. HSP72 was expressed in SA group but not in control group and oppositely NF-kappaB was expressed in control group but not in DXR group. Serum AST, TNF-alpha, CINC and MIP-2 concentrations were significantly lower in DXR group than in control group (P < 0.05). The survival rate of 7 days was significantly higher in DXR group than in control group (50% vs. 0%, P < 0.05).

CONCLUSIONS

These data suggested that long-term cold ischemia-reperfusion injury was attenuated in liver graft with pretreatment of DXR. The induction of HSP72 may offer protection to hepatocytes by restraining the activation of NF-kappaB and inflammation.

Inhibitory effect of Patrinia scabiosaefolia on acute pancreatitis

AIM: To investigate the effect of Patrinia scabiosaefolia (PS) on the cholecystokinin (CCK) octapeptide- induced acute pancreatitis (AP) in rats.

METHODS: Wistar rats weighing 240-260 g were divided into three groups: (1) Normal saline-treated group; (2) treatment with PS at 100 mg/kg group, in which PS was administered orally, followed by subcutaneous administration of 75 µg/kg CCK octapeptide three times after 1, 3 and 5 h, and this whole procedure was repeated for 5 d; (3) treatment with saline group, in which the protocols were the same as in treatment group with PS. We determined the pancreatic weight/body weight ratio, the levels of pancreatic HSP60, HSP72 and the secretion of pro-inflammatory cytokines. Repeated CCK octapeptide treatment resulted in the typical laboratory findings of experimentally induced pancreatitis.

RESULTS: PS reduced the pancreatic weight/body weight ratio, the levels of serum amylase and lipase, and inhibited expressions of pro-inflammatory cytokines in the CCK octapeptide-induced AP. Furthermore, PS pretreatment increased the pancreatic levels of HSP60 and HSP72.

CONCLUSION: Pretreatment with PS has an anti-inflammatory effect on CCK octapeptide-induced AP.

Radiofrequency radiation does not induce stress response in human T-lymphocytes and rat primary astrocytes

Heat shock proteins (HSPs) are rapidly induced by a variety of stressors, including heat shock, ethanol, heavy metals, UV, and gamma-radiation. Mitogen-activated protein kinases (MAPKs) are also involved in the stress transduction pathways in all eukaryotes. In this study, we attempted to determine whether radiofrequency (RF) radiation is able to induce a non-thermal stress response. Human T-lymphocyte Jurkat cells and rat primary astrocytes were exposed to 1763 MHz of RF radiation at an average specific absorption rate (SAR) of either 2 W/kg or 20 W/kg, for 30 min or 1 h. Temperature was completely controlled at 37 +/- 0.2 degrees C throughout the exposure period. The sham exposures were performed under exactly identical experimental conditions without exposure to RF radiation. We assessed alterations in the expression of HSPs and the activation of MAPKs in the RF-exposed cells. No detectable difference was observed in the expression levels of HSP90, HSP70, and HSP27. The phosphorylation status of MAPKs, extracellular signal-regulated kinases (ERK1/2), c-Jun N-terminal protein kinases (JNK1/2), or p38, did not change significantly. In order to determine whether RF radiation can promote the effects of 12-O-tetradecanoylphorbol 13-acetate (TPA) on stress response, cells were exposed to RF radiation coupled with TPA treatment. When TPA alone was applied, the MAPKs were found to be phosphorylated in a dose-dependent manner. However, RF radiation did not result in any enhancement of TPA-induced MAPK phosphorylation. Neither TPA nor RF radiation exerted any detectable effect on the induction of HSPs. These results indicate that 1763 MHz RF radiation alone did not elicit any stress response, nor did it have any effect on TPA-induced MAPK phosphorylation, under our experimental conditions.

Expression of matrix metalloproteinase 2 and heat shock protein-72 in immobilized muscle in rats

Metalloproteinases (MMPs) are proteolytic enzymes that function in the extracellular matrix to degrade connective tissues. While it is clear that certain induced skeletal muscle pathologies promote increased expression of MMP-2 and heat shock protein- 72 (HSP-72), the relationship between muscle disuse and expression of MMP-2 and HSP-72 in muscles is unknown. These experiments tested the hypothesis that knee immobilization induced expression of MMP-2 and HSP-72 is disuse-dependent in a way that short-term joint immobilization increases HSP-72 expression, whereas long-term joint immobilization increases MMP-2 expression in skeletal muscles. Male rats (8 months old) completed 1, 2, 3, and 4 weeks of knee joint immobilization. Muscle mRNA and protein levels of MMP-2 and HSP-72 were assessed in Gastrocnemius (Gast), Superficial and Deep Quadriceps, and Soleus (Sol) muscles by reverse transcriptase-polymerase chain reaction and western blotting, respectively. Results reveal that during the first two weeks of immobilization there is increased protein levels of HSP-72 and expression of mRNA of HSP-72 mainly in slow twitch muscle fibers. However, 3 and 4 weeks of joint immobilization increased both mRNA and protein levels of MMP-2 in skeletal muscles containing a high percentage of fast type II fibers (i.e., Gast and superficial quadriceps). These results support the hypothesis that different periods of muscle disuse induced different proteins expression, and that the influence of joint immobilization on the expression of HSP-72 in the short-term, and MMP-2 in the long ran is associated to fiber types.

Increased expression of 70 kD heat shock protein in cultured primary human keratinocytes induced by human papillomavirus 16 E6/E7 gene

BACKGROUND

Heat shock protein 70 (HSP70) is expressed highly in epithelial tumours associated closely with human papillomavirus 16 (HPV16) infections. However, evidence about the direct relationship between HSP70 expression and HPVs infections are still lacking. In the present study, we examined the expression of HSP70 in keratinocytes introduced with HPV16 E6/E7 oncogenes.

METHODS

Stable transfected cells were established by transfection of the plasmids pLXSN16E6/E7 into cultured primary keratinocytes and subsequently selected by plasmid specific selection antibiotic (G418) at the required concentration. The expression of HSP70 in pLXSN16E6/E7 transfected keratinocytes was determined by Western blot. The correlation of HSP70 expression and E6/E7 transfection was further confirmed by doubly labelled immunofluorescent staining.

RESULTS

Compared to non-transfected keratinocytes, there was a significant trend for higher levels of HSP70 in pLXSN16E6/E7 transfected keratinocytes. Doubly labelled immunofluorescent staining experiment showed that the co-localization of HPV16 E6/E7 and HSP70 in transfected keratinocytes was observed and increased expression of HSP70 was strongly associated with the transfection of HPV16 E6/E7.

CONCLUSIONS

Our studies demonstrated increased levels of HSP70 proteins in keratinocytes stably transfected by HPV16 E6/E7 oncogenes. It suggests that the expression of HSP70 is modulated by HPV16 E6/E7 proteins, which may be involved in HPV16 E6/E7 induced immortalization.

Immunohistochemical detection of the inducible heat shock protein hsp70: a methodological study

Stress-inducible Hsp70i and constitutively expressed Hsc70 are highly related heat shock proteins. Aberrant expression levels and intracellular localization of these proteins has been suggested as a potential marker in certain tumors. The aim of our study was to work out a reliable, immunohistochemical detection of the stress-inducible Hsp70i protein and enabling discrimination between Hsp70i and Hsc70 proteins in paraffin-embedded human tissues. We tested the effect of several fixative procedures and antigen retrieval on the effectiveness of the Hsp70i detection in murine cells cultured in vitro and in liver of rats subjected to heat shock. For cells grown in vitro, specific Hsp70i immunoreactivity was obtained with all fixatives used. However, samples fixed in 10% formalin and 4% paraformaldehyde required antigen retrieval. In liver tissue embedded in paraffin, regardless the fixative used, positive Hsp70i staining could be visible only if antigen retrieval was applied. We applied this procedure for detection of Hsp70i in routine sections of breast and lung cancers fixed with 10% formalin and found that the application of thermal antigen retrieval significantly enhanced the SPA810 immunoreactivity and reduced background staining. This procedure enabled also the differential detection of Hsp70i and Hsc70 in routine histopathological preparations.

[Effect of Xingding Injection on expression of heat shock protein 72 in vascular endothelial cells]

OBJECTIVE

To study the effect of Xingding Injection on the expression of heat shock protein 72 (HSP 72) in vascular endothelial cells after ultraviolet radiation.

METHODS

Porcine aortic endothelial cells were cultured for 72 hours in culture mediums with different concentrations (0.1, 0.5, 1.0, 5.0, 10 mg/ml) of Xingding Injection. Ultraviolet radiation was administered to the cultured cells for 30 minutes. Western-blot assay was used to measure the expression of HSP 72 in the vascular endothelial cells.

RESULTS

There was no expression of HSP 72 in the cultured vascular endothelial cells without ultraviolet radiation, but there was some expression of HSP 72 after ultraviolet radiation. Xingding Injection of different concentrations could significantly improve the expression of HSP 72. The expression of HSP 72 in the vascular endothelial cells cultured in culture medium with 1.0 mg/ml Xingding Injection was the highest, and there was no more increase of expression when the concentration was higher, instead the expression decreased.

CONCLUSION

Xingding Injection can protect the vascular endothelial cells from injury during stress. It may be one of its mechanisms in preventing and treating cardio-cerebrovascular disorders.

The HSP expression of passive repetitive plyometric trained skeletal muscle

This study aims to understand the effect of ten-week passive repetitive plyometric (PRP) training on human skeletal muscle and the application of PRP training for performance. Vastus lateralis of nine candidates were aspirated before (pre) and after (post) PRP training. Histochemical approaches with regular hematoxylene-eosin (HE) and Mallory's phosphotungstic acid hematoxylin (PTAH) stains were used to demonstrate the changes of muscle fibers. Immunohistochemical studies with heat shock protein (anti-hsp72, Stressgen, Canada) were employed to display cellular activities. Each set of slides was quantitatively analyzed by using a modified morphometric method (Russ and Dehoff, 1999) on a Nikon ECLIPSE 80i microscope, equipped with an Evolution VF COOLED color video camera, and the Image-Pro Plus software (5.0 for Win; Media Cybernetics, USA). Finally, hsp72 mRNAs of both pre-PRP and post-PRP specimens were amplified through RT-PCR. Signal intensities were read by a densitometer and analyzed through the SPSS (11.0 for Win) statistically. Post-PRP muscle cells demonstrated hypertrophic change with increased cellular content and a narrowed inter-cellular space according to both HE and PTAH profiles. Post-PRP cellular hsp72 proteins were higher by up to five percent, as measured by a gray-scale reading. Further, after a training period of 10 weeks, hsp72 mRNA expression was several times higher.