The 70-kDa heat shock protein (Hsp70) as a therapeutic target for stroke

The Effect of Human HSP70 Administration on a Mouse Model of Alzheimer's Disease Strongly Depends on Transgenicity and Age

In humans, heat shock protein 70 is a key component of the machinery that protects neuronal cells from various stress conditions and whose production significantly declines during aging. Herein, we investigated the protective effect of sub-chronic intranasal administration of human Hsp70 on the state of neurons in the temporal cortex and areas of the hippocampus of old transgenic (Tg) 5XFAD mice (11-13 months), representing a late-onset model of hereditary Alzheimer's disease. Quantitative analysis of the various neuronal pathologies between the two groups (Tg versus nTg) revealed maximal levels of abnormalities in the brains of aged Tg mice. Importantly, intranasal application of HSP70 had profound beneficial effects on neuron morphology in the temporal cortex and hippocampal regions when applied to the aged Tg mice but not in the case of age-matched, non-transgenic, littermate animals. Furthermore, the effect of HSP70 administration on neurons in the hippocampus and temporal cortex differed characteristically between the groups. Using RNA-Seq, we identified a lot of differentially expressed genes in the hippocampus of old Tg mice compared with those of nTg mice. Most importantly, we observed HSP70-induced upregulation of multiple genes participating in antigen processing and presentation especially the members of major histocompatibility complex (class I and II) in the brains of old 5XFAD Tg animals, suggesting that Hsp70 executes its beneficial role via activation of adaptive immunity. Overall, our data enable to conclude that Hsp70 treatment may be a safe and effective therapeutic application against Alzheimer-type neuropathologies manifested at the late stages of the disease.

Extracellular Vesicles Derived from Neural Progenitor Cells--a Preclinical Evaluation for Stroke Treatment in Mice

Stem cells such as mesenchymal stem cells (MSCs) enhance neurological recovery in preclinical stroke models by secreting extracellular vesicles (EVs). Since previous reports have focused on the application of MSC-EVs only, the role of the most suitable host cell for EV enrichment and preclinical stroke treatment remains elusive. The present study aimed to evaluate the therapeutic potential of EVs derived from neural progenitor cells (NPCs) following experimental stroke. Using the PEG technique, EVs were enriched and characterized by electron microscopy, proteomics, rt-PCR, nanosight tracking analysis, and Western blotting. Different dosages of NPC-EVs displaying a characteristic profile in size, shape, cargo protein, and non-coding RNA contents were incubated in the presence of cerebral organoids exposed to oxygen-glucose deprivation (OGD), significantly reducing cell injury when compared with control organoids. Systemic administration of NPC-EVs in male C57BL6 mice following experimental ischemia enhanced neurological recovery and neuroregeneration for as long as 3 months. Interestingly, the therapeutic impact of such NPC-EVs was found to be not inferior to MSC-EVs. Flow cytometric analyses of blood and brain samples 7 days post-stroke demonstrated increased blood concentrations of B and T lymphocytes after NPC-EV delivery, without affecting cerebral cell counts. Likewise, a biodistribution analysis after systemic delivery of NPC-EVs revealed the majority of NPC-EVs to be found in extracranial organs such as the liver and the lung. This proof-of-concept study supports the idea of EVs being a general concept of stem cell–induced neuroprotection under stroke conditions, where EVs contribute to reverting the peripheral post-stroke immunosuppression.

Natural genetic variation in Stim1 creates stroke in the spontaneously hypertensive rat

Similar to humans, the risk of cerebrovascular disease in stroke-prone spontaneously hypertensive rats (SHR-A3/SHRSP) arises from naturally occurring genetic variation. In the present study, we show the involvement of genetic variation affecting the store-operated calcium signaling gene, Stim1, in the pathogenesis of stroke in SHR. Stim1 is a key lymphocyte activation signaling molecule and contains functional variation in SHR-A3 that diverges from stroke-resistant SHR-B2. We created a SHR-A3 congenic line in which Stim1 was substituted with the corresponding genomic segment from SHR-B2. Compared with SHR-A3 rats, Stim1 congenic SHR-A3 (SHR-A3(Stim1-B2)) have reduced cerebrovascular disease in response to salt loading including lower neurological deficit scores and cerebral edema. Microbleeds and major hemorrhages occurred in over half of SHR-A3 rats. These lesions were absent in SHR-A3(Stim1-B2) rats. Loss of Stim1 function in mice and humans is associated with antibody-mediated autoimmunity due to defects in T lymphocyte helper function to B cells. We investigated autoantibody formation using a high-density protein array to detect the presence of IgG and IgM autoantibodies in SHR-A3. Autoantibodies to key cerebrovascular stress proteins were detected that were reduced in the congenic line.

Chaperone-Based Therapeutic Target Innovation: Heat Shock Protein 70 (HSP70) for Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is still a global health problem. Current T2DM treatments are limited to curing the symptoms and have not been able to restore insulin sensitivity in insulin-sensitive tissues that have become resistant. In the past decade, some studies have shown the significant role of a chaperone family, heat shock protein 70 (HSP70), in insulin resistance pathogenesis that leads to T2DM. HSP70 is a cytoprotective molecular chaperone that functions in protein folding and degradation. In general, studies have shown that decreased concentration of HSP70 is able to induce inflammation process through JNK activation, inhibit fatty acid oxidation by mitochondria through mitophagy decrease and mitochondrial biogenesis, as well as activate SREBP-1c, one of the lipogenic gene transcription factors in ER stress. The overall molecular pathways are potentially leading to insulin resistance and T2DM. Increased expression of HSP70 in brain tissues is able to improve insulin sensitivity and glycemic control specifically. HSP70 modulation-targeting strategies (including long-term physical exercise, hot tub therapy (HTT), and administration of alfalfa-derived HSP70 (aHSP70)) in subjects with insulin resistance are proven to have therapeutic and preventive potency that are promising in T2DM management.

Proteomics Analysis of Brain Tissue in a Rat Model of Ischemic Stroke in the Acute Phase

Background: Stroke is a leading health issue, with high morbidity and mortality rates worldwide. Of all strokes, approximately 80% of cases are ischemic stroke (IS). However, the underlying mechanisms of the occurrence of acute IS remain poorly understood because of heterogeneous and multiple factors. More potential biomarkers are urgently needed to reveal the deeper pathogenesis of IS.

Methods: We identified potential biomarkers in rat brain tissues of IS using an iTRAQ labeling approach coupled with LC-MS/MS. Furthermore, bioinformatrics analyses including GO, KEGG, DAVID, and Cytoscape were used to present proteomic profiles and to explore the disease mechanisms. Additionally, Western blotting for target proteins was conducted for further verification.

Results: We identified 4,578 proteins using the iTRAQ-based proteomics method. Of these proteins, 282 differentiated proteins, comprising 73 upregulated and 209 downregulated proteins, were observed. Further bioinformatics analysis suggested that the candidate proteins were mainly involved in energy liberation, intracellular protein transport, and synaptic plasticity regulation during the acute period. KEGG pathway enrichment analysis indicated a series of representative pathological pathways, including energy metabolite, long-term potentiation (LTP), and neurodegenerative disease-related pathways. Moreover, Western blotting confirmed the associated candidate proteins, which refer to oxidative responses and synaptic plasticity.

Conclusions: Our findings highlight the identification of candidate protein biomarkers and provide insight into the biological processes involved in acute IS.

Cofilin-actin rod formation in experimental stroke is attenuated by therapeutic hypothermia and overexpression of the inducible 70 kD inducible heat shock protein (Hsp70)

BACKGROUND AND PURPOSE

Cofilin-actin rods are covalently linked aggregates of cofilin-1 and actin. Under ischemic conditions, these rods have been observed in neuronal dendrites and axons and may contribute to the loss of these processes. Hypothermia (Hypo) and the 70 kD inducible heat shock protein (Hsp70) are both known to improve outcomes after stroke, but the mechanisms are uncertain. Here, we evaluated the effect of these factors on cofilin-actin rod formation in a mouse model of stroke.

MATERIALS AND METHODS

Mice were subjected to distal middle cerebral artery occlusion (dMCAO) and treated with Hypo using a paradigm previously shown to be neuroprotective. We similarly studied mice that overexpressed transgenic (Tg) or were deficient knockout (Ko) in the inducible 70 kDa heat shock protein (Hsp70), also previously shown to be protective by our group and others. Cofilin-actin rod formation was assessed by histological analysis at 4 and 24 h after dMCAO. Its expression was analyzed in three different regions, namely, infarct core (the center of the infarct), middle cerebral artery (MCA) borderzone (the edge of the brain regions supplied by the MCA), and the ischemic borderzone (border of ischemic lesion). Ischemic lesion size and neurological deficits were also assessed.

RESULTS

Both Hypo-treated and Hsp70 Tg mice had smaller lesion sizes and improved neurological outcomes, whereas Hsp70 Ko mice had larger lesion sizes and worsened neurological outcomes. Cofilin-actin rods were increased after stroke, but were reduced by therapeutic Hypo and in Hsp70 Tg mice. In contrast, cofilin-actin rods were increased in ischemic brains of Hsp70 Ko mice.

CONCLUSIONS

Cofilin-actin rod formation was suppressed under the conditions of neuroprotection and increased under circumstances where outcome was worsened. This suggests that cofilin-actin rods may act to participate in or exacerbate ischemic pathology and warrants further study as a potential therapeutic target.

Effects of Pseudomonas aeruginosa on Microglial-Derived Extracellular Vesicle Biogenesis and Composition

The packaging of molecular constituents inside extracellular vesicles (EVs) allows them to participate in intercellular communication and the transfer of biological molecules, however the role of EVs during bacterial infection is poorly understood. The goal of this study was to examine the effects of Pseudomonas aeruginosa (P. aeruginosa) infection on the biogenesis and composition of EVs derived from the mouse microglia cell line, BV-2. BV-2 cells were cultured in exosome-free media and infected with 0, 1.3 × 10⁴, or 2.6 × 10⁴ colony forming units per milliliter P. aeruginosa for 72 h. The results indicated that compared with the control group, BV-2 cell viability significantly decreased after P. aeruginosa infection and BV-2-derived EVs concentration decreased significantly in the P. aeruginosa-infected group. P. aeruginosa infection significantly decreased chemokine ligand 4 messenger RNA in BV-2-derived infected EVs, compared with the control group (p ≤ 0.05). This study also revealed that heat shock protein 70 (p ≤ 0.05) and heat shock protein 90β (p ≤ 0.001) levels of expression within EVs increased after P. aeruginosa infection. EV treatment with EVs derived from P. aeruginosa infection reduced cell viability of BV-2 cells. P. aeruginosa infection alters the expression of specific proteins and mRNA in EVs. Our study suggests that P. aeruginosa infection modulates EV biogenesis and composition, which may influence bacterial pathogenesis and infection.

Heat shock protein signaling in brain ischemia and injury

Heat shock proteins (HSPs) are chaperones that catalyze the refolding of denatured proteins. In addition to their ability to prevent protein denaturation and aggregation, the HSPs have also been shown to modulate many signaling pathways. Among HSPs, the inducible 70 kDa HSP (HSP70) has especially been shown to improve neurological outcome in experimental models of brain ischemia and injury. HSP70 can modulate various aspects of the programmed cell death pathways and inflammation. This review will focus on potential mechanisms of the neuroprotective effects of HSP70 in stroke and brain trauma models. We also comment on potential ways in which HSP70 could be translated into clinical therapies.

Effect of thermal preconditioning on Hsp70 expression in the medulla oblongata and on hemodynamics during passive hyperthermia

A short-term episode of elevated core body temperature that induces Hsp70 expression (thermal preconditioning) may protect against heatstroke during subsequent hyperthermia. The protective effects of thermal preconditioning may involve several cellular and immunological mechanisms and improvements in baroreflex sensitivity. To substantiate the hypothesis that the protective effect of thermal preconditioning also occurs in conditions with intact thermoregulation, we examined the evolution of spontaneous cardiovagal baroreflex sensitivity and the protective effect of Hsp70 expression after thermal preconditioning in nonanesthetized Wistar-Kyoto rats with implanted telemetric transmitters. In the baroreflex centers of the medulla oblongata, thermal preconditioning induced Hsp70 in perineuronal and perivascular oligodendrocytes, microglia, and endothelial cells but not in neurons. The maximal Hsp70 expression was detected 4 h after preconditioning, but a significant number of Hsp70-positive cells was still present 72 h after preconditioning. Increased c-Fos expression in the neurons of baroreflex centers was detectable only 4 h after preconditioning. The mean values of cardiovagal baroreflex sensitivity did not show significant differences during the 72-hour follow-up period after thermal preconditioning. Similarly, cardiovascular variability measures of the autonomic nervous system activity were also not significantly affected by thermal preconditioning. During passive hyperthermia, thermal preconditioning had no statistically significant effect on thermoregulation and the onset of arterial pressure decline. Our data suggest that thermal preconditioning induces a glial type of Hsp70 expression in the baroreflex centers of the medulla oblongata. However, this response was not associated with cardiovagal baroreflex sensitization and protection against hemodynamic instability during passive hyperthermia.

Epigenetic Alterations of Heat Shock Proteins (HSPs) in Cancer

Heat shock proteins (HSPs) are associated with various physiological processes (protein refolding and degradation) involved in the responses to cellular stress, such as cytotoxic agents, high temperature, and hypoxia. HSPs are overexpressed in cancer cells and play roles in their apoptosis, invasion, proliferation, angiogenesis, and metastasis. The regulation or translational modification of HSPs is recognized as a therapeutic target for the development of anticancer drugs. Among the regulatory processes associated with HSP expression, the epigenetic machinery (miRNAs, histone modification, and DNA methylation) has key functions in cancer. Moreover, various epigenetic modifiers of HSP expression have also been reported as therapeutic targets and diagnostic markers of cancer. Thus, in this review, we describe the epigenetic alterations of HSP expression in cancer cells and suggest that HSPs be clinically applied as diagnostic and therapeutic markers in cancer therapy via controlled epigenetic modifiers.

HSPA8/HSC70 in Immune Disorders: A Molecular Rheostat that Adjusts Chaperone-Mediated Autophagy Substrates

HSPA8/HSC70 is a molecular chaperone involved in a wide variety of cellular processes. It plays a crucial role in protein quality control, ensuring the correct folding and re-folding of selected proteins, and controlling the elimination of abnormally-folded conformers and of proteins daily produced in excess in our cells. HSPA8 is a crucial molecular regulator of chaperone-mediated autophagy, as a detector of substrates that will be processed by this specialized autophagy pathway. In this review, we shortly summarize its structure and overall functions, dissect its implication in immune disorders, and list the known pharmacological tools that modulate its functions. We also exemplify the interest of targeting HSPA8 to regulate pathological immune dysfunctions.

Molecular chaperones in the brain endothelial barrier: neurotoxicity or neuroprotection?

Brain microvascular endothelial cells (BMECs) interact with astrocytes and pericytes to form the blood-brain barrier (BBB). Their compromised function alters the BBB integrity, which is associated with early events in the pathogenesis of cancer, neurodegenerative diseases, and epilepsy. Interestingly, these conditions also induce the expression of heat shock proteins (HSPs). Here we review the contribution of major HSP families to BMEC and BBB function. Although investigators mainly report protective effects of HSPs in brain, contrasted results were obtained in BMEC, which depend both on the HSP and on its location, intra- or extracellular. The therapeutic potential of HSPs must be scrupulously analyzed before targeting them in patients to reduce the progression of brain lesions and improve neurologic outcomes in the long term.-Thuringer, D., Garrido, C. Molecular chaperones in the brain endothelial barrier: neurotoxicity or neuroprotection?

Combined Cyclosporin A and Hypothermia Treatment Inhibits Activation of BV-2 Microglia but Induces an Inflammatory Response in an Ischemia/Reperfusion Hippocampal Slice Culture Model

Introduction

Hypothermia attenuates cerebral ischemia-induced neuronal cell death associated with neuroinflammation. The calcineurin inhibitor cyclosporin A (CsA) has been shown to be neuroprotective by minimizing activation of inflammatory pathways. Therefore, we investigated whether the combination of hypothermia and treatment with CsA has neuroprotective effects in an oxygen-glucose deprivation/reperfusion (OGD/R) injury model in neuronal and BV-2 microglia monocultures, as well as in an organotypic hippocampal slice culture (OHSC).

Methods

Murine primary neurons, BV-2 microglia, and OHSC were pretreated with CsA and exposed to 1 h OGD (0.2% O₂) followed by reperfusion at normothermia (37°C) or hypothermia (33.5°C). Cytotoxicity was measured by lactate dehydrogenase and glutamate releases. Damage-associated molecular patterns (DAMPs) high mobility group box 1 (HMGB1), heat shock protein 70 (Hsp70), and cold-inducible RNA-binding protein (CIRBP) were detected in cultured supernatant by western blot analysis. Interleukin-6 (IL-6), Interleukin-1α and -1β (IL-1α/IL1-β), tumor necrosis factor-α (TNF-α), monocyte chemotactic protein 1 (MCP1), inducible nitric oxide synthase (iNOS), glia activation factors ionized calcium-binding adapter molecule 1 (Iba1), and transforming growth factor β1 (TGF-β1) gene expressions were analyzed by RT-qPCR.

Results

Exposure to OGD plus 10 μM CsA was sufficient to induce necrotic cell death and subsequent release of DAMPs in neurons but not BV-2 microglia. Moreover, OGD/R-induced secondary injury was also observed only in the neurons, which was not attenuated by cooling and no increased toxicity by CsA was observed. BV-2 microglia were not sensitive to OGD/R-induced injury but were susceptible to CsA-induced toxicity in a dose dependent manner, which was minimized by hypothermia. CsA attenuated IL-1β and Iba1 expressions in BV-2 microglia exposed to OGD/R. Hypothermia reduced IL-1β and iNOS expressions but induced TNF-α and Iba1 expressions in the microglia. However, these observations did not translate to the ex vivo OHCS model, as general high expressions of most cytokines investigated were observed.

Conclusion

Treatment with CsA has neurotoxic effects on primary neurons exposed to OGD but could inhibit BV-2 microglia activation. However, CsA and hypothermia treatment after ischemia/reperfusion injury results in cytotoxic neuroinflammation in the complex ex vivo OHSC.

Tat-HSP70 protects neurons from oxidative damage in the NSC34 cells and ischemic damage in the ventral horn of rabbit spinal cord

Heat shock protein 70 (HSP70) is an ATP-dependent molecular chaperone, and it has been shown that its levels increase after exposure to various types of stress, including ischemia. In the present study, we investigated the effects of HSP70 against H₂O₂-induced neuronal stress in NSC34 cells and against spinal cord ischemia in rabbits. Tat-HSP70 proteins facilitated the intracellular delivery of HSP70 into the NSC34 cells and enabled them to cross the blood-brain barrier in the rabbit spinal cord. Tat-HSP70 was effectively transduced into NSC34 cells in a concentration- and time-dependent manner, while control-HSP70 protein could not be delivered intracellularly at any concentration or time after treatment. Treatment with Tat-HSP70 reduced the generation of reactive oxygen species and cell death induced by H₂O₂, while the control-HSP70 did not show any significant effect on the NSC34 cells exposed to H₂O₂. In rabbit spinal cord, the administration of Tat-HSP70 showed significant amelioration of neurological defects and neuronal death in the ventral horn of spinal cord. In addition, Tat-HSP70 treatment significantly reduced lipid peroxidation and increased Cu, Zn-superoxide dismutase activities in the spinal cord, but glutathione peroxidase and Mn-superoxide dismutase activities remained unchanged. These results suggest that Tat-HSP70, not control-HSP70, decreases cell damage by reducing oxidative stress in NSC34 cells and rabbit spinal cord, and it can be employed for the reduction of neuronal damage caused after spinal cord ischemia.

Tóth O, Török Z, Varga DP, Menyhárt Á, Frank R, Hantosi D, Hunya Á, Bari F, Horváth I, Vigh L, Farkas E. The impact of dihydropyridine derivatives on the cerebral blood flow response to somatosensory stimulation and spreading depolarization

BACKGROUND AND PURPOSE

A new class of dihydropyridine derivatives, which act as co-inducers of heat shock protein but are devoid of calcium channel antagonist and vasodilator effects, has recently been developed with the purpose of selectively targeting neurodegeneration. Here, we evaluated the action of one of these novel compounds LA1011 on neurovascular coupling in the ischaemic rat cerebral cortex. As a reference, we applied nimodipine, a vasodilator dihydropyridine and well-known calcium channel antagonist.

EXPERIMENTAL APPROACH

Rats were treated with LA1011 or nimodipine, either by chronic, systemic (LA1011), or acute, local administration (LA1011 and nimodipine). In the latter treatment group, global forebrain ischaemia was induced in half of the animals by bilateral common carotid artery occlusion under isoflurane anaesthesia. Functional hyperaemia in the somatosensory cortex was created by mechanical stimulation of the contralateral whisker pad under α-chloralose anaesthesia. Spreading depolarization (SD) events were elicited subsequently by 1 M KCl. Local field potential and cerebral blood flow (CBF) in the parietal somatosensory cortex were monitored by electrophysiology and laser Doppler flowmetry.

KEY RESULTS

LA1011 did not alter CBF, but intensified SD, presumably indicating the co-induction of heat shock proteins, and, perhaps an anti-inflammatory effect. Nimodipine attenuated evoked potentials and SD. In addition to the elevation of baseline CBF, nimodipine augmented hyperaemia in response to both somatosensory stimulation and SD, particularly under ischaemia.

CONCLUSIONS AND IMPLICATIONS

In contrast to the CBF improvement achieved with nimodipine, LA1011 seems not to have discernible cerebrovascular effects but may up-regulate the stress response.

Genetic and Pharmacological Targeting of Heat Shock Protein 70 in the Mouse Amygdala-Kindling Model

Inflammatory responses involving Toll-like receptor signaling represent a key factor contributing to epileptogenesis. Thus, it is of particular interest to explore the relevance of toll-like receptor ligands and modulators, such as heat shock protein 70 (HSP70). Motivated by recent findings demonstrating an upregulation of HSP70 in a model of epileptogenesis, we analyzed the consequences of genetic and pharmacological targeting of HSP70 expression in a mouse kindling paradigm. Lack of inducible HSP70 resulted in increased prekindling seizure thresholds. However, at threshold stimulation the deficiency-promoted seizure spread, as indicated by an increased seizure severity. Subsequent kindling stimulations elicited more severe seizures in knockout mice, whereas endogenous termination of seizure activity remained unaffected with duration of behavioral and electrographic seizure activity comparable to that of wild-type mice. Interestingly, HSP70 deficiency resulted in enhanced microglia activation in the CA1 region. Next, we assessed a pharmacological targeting approach aiming to promote HSP70 expression. Celastrol treatment had no impact on kindling progression but reduced postkindling seizure thresholds and enhanced microglia activation in CA1 and CA3. In conclusion, the findings from HSP70-knockout mice support a protective role of HSP70 with an effect on microglia activation and spread of seizure activity. Unexpectedly, celastrol administration resulted in detrimental consequences. These findings should be considered as a warning about the general safety of celastrol as a drug candidate. The impact of pathophysiological mechanisms on the quality of celastrol effects requires comprehensive future studies exploring influencing factors. Moreover, alternate strategies to increase HSP70 expression should be further developed and validated.

The Ethanolic Extract of Caesalpinia sappan Heartwood Inhibits Cerebral Ischemia/Reperfusion Injury in a Rat Model Through a Multi-Targeted Pharmacological Mechanism

Background: Caesalpinia sappan L. (C. sappan) is a traditional Chinese medicinal plant. The dried heartwood of C. sappan (also known as Sappan wood) has been widely used for the folkloric medical treatment of ischemic cerebral stroke in China. However, the detailed underlying pharmacological mechanism still remains largely unexplored. Methods: In this study, a middle cerebral artery occlusion (MCAO) rat model was employed to elucidate the mechanism of the anti-cerebral ischemic effects of C. sappan ethanolic extract (CEE). Moreover, systemic multi-target identification coupled with gene ontology biological process (GO BP) and reactome pathway analysis was used to investigate the potential neuroprotective mechanism. Furthermore, the presumed mechanism was confirmed through biological analysis by determining the effects of CEE on the identified signaling pathways in PC12 cells model-induced by oxygen-glucose deprivation/reperfusion (OGD/R). Results: Our study demonstrates that CEE (both through in vivo administration at a dosage of 300 mg/kg and through in vitro incubation at a dosage of 2.4 μg/mL) is a neuroprotective agent that can effectively inhibit neuronal damage, promote synaptic generation, and suppress the activation of neutrophils, microglia, and astrocytes. Moreover, the neuroprotective mechanism of CEE is mediated via regulating 150 potential target proteins, which are associated with 6 biological processes and 10 pathways, including JAK-STAT, HSP90 and DNA damage/telomere stress. Conclusion: CEE can exert neuroprotective effect through multi-target pharmacological mechanisms to prevent ischemia/reperfusion-induced cerebral injury.

The Effects of Mouse Recombinant Resistin on mRNA Expression of Proinflammatory and Anti-Inflammatory Cytokines and Heat Shock Protein-70 in Experimental Stroke Model

BACKGROUND

Our recent research showed that resistin has a neuroprotective effect against stroke-induced injury through suppressing apoptosis and oxidative stress. However, the molecular mechanism of neuroprotection of resistin is unclear. This work was designed to examine the effect of mouse recombinant resistin on mRNA expression of Tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), Interleukin-10 (IL-10), Transforming growth factor-β1 (TGF- β1), and Heat shock protein-70 (HSP-70) in mouse model of stroke.

MATERIALS AND METHODS

Transient focal cerebral ischemia was induced by the middle cerebral artery occlusion (MCAO) in mice. TNF-α, IL-1β, IL-10, TGF-β1, and HSP-70 mRNA were detected at sham (0 hour), 3 hours, 6 hours, 12 hours, and 24 hours after MCAO using real-time QRT-PCR method. Moreover, animals were treated with resistin at the dose of 400ng/mouse at the commencement of MCAO, and mRNA expression of the cytokines and HSP-70 was measured 24 hours after MCAO.

RESULTS

Tumor necrosis factor-α and IL-1β mRNA expression markedly increased at 12-hour time point and then returned to the basal level at 24 hours after MCAO; but HSP-70 mRNA expression increased at 24-hour time point. Furthermore, resistin (400 ng/mouse) significantly increased TGF-β1 and IL-10 and decreased HSP-70 gene expression at 24 hours after MCAO.

CONCLUSIONS

Our findings revealed that a molecular mechanism of attenuating ischemic damage by resistin administration probably is increased mRNA expression of anti-inflammatory cytokines. However, applying resistin in the clinical settings for the treatment of stroke deserves further researches in the future.