Brain-derived heat shock protein 70-peptide complexes induce NK cell-dependent tolerance to experimental autoimmune encephalomyelitis

Extracellular vesicle-associated small heat shock proteins as therapeutic agents in neurodegenerative diseases and beyond

Increasing evidence points towards using extracellular vesicles (EVs) as a therapeutic strategy in neurodegenerative diseases such as multiple sclerosis, Parkinson's, and Alzheimer's disease. EVs are nanosized carriers that play an essential role in intercellular communication and cellular homeostasis by transporting an active molecular cargo, including a large variety of proteins. Recent publications demonstrate that small heat shock proteins (HSPBs) exhibit a beneficial role in neurodegenerative diseases. Moreover, it is defined that HSPBs target the autophagy and the apoptosis pathway, playing a prominent role in chaperone activity and cell survival. This review elaborates on the therapeutic potential of EVs and HSPBs, in particular HSPB1 and HSPB8, in neurodegenerative diseases. We conclude that EVs and HSPBs positively influence neuroinflammation, central nervous system (CNS) repair, and protein aggregation in CNS disorders. Moreover, we propose the use of HSPB-loaded EVs as advanced nanocarriers for the future development of neurodegenerative disease therapies.

Comparative peptidome profiling reveals critical roles for peptides in the pathology of pancreatic cancer

BACKGROUNDS/AIMS

Pancreatic cancer is a digestive system tumour disease with a notably poor prognosis and a 5-year survival rate of less than 10 %. In recent years, peptide drugs have shown great clinical value in antitumour applications. We aim to identify differentially expressed peptides by using peptidomics techniques to explore the mechanisms involved in the development and pathology of pancreatic cancer.

METHODS

We performed peptidomic analysis of pancreatic cancer and paired paracancerous tissues by using ITRAQ labelling technology and conducted in-depth bioinformatics analysis and functional studies on differentially expressed peptides.

RESULTS

A total of 2,881 peptides were identified, of which 133 were differentially expressed (116 were upregulated and 17 were downregulated). By using GO analysis, the differentially expressed peptides were found to be closely related to the tumour microenvironment and extracellular matrix. KEGG enrichment analysis revealed that precursor proteins were closely related to the T2DM and RAS signalling pathways. The endogenous peptide P1DG can significantly inhibit the proliferation, migration and invasion of pancreatic cancer cells.

CONCLUSION

P1DG and its precursor GAPDH may be closely related to the proliferation, migration and invasion of pancreatic cancer. Peptidomics can aid in understanding the pathogenesis of pancreatic cancer more comprehensively.

NK Cell Induced T Cell Anergy Depends on GRAIL Expression

NK cells (natural killer cells) being a part of the innate immune system have been shown to be involved in immunoregulation of autoimmune diseases. Previously we have shown that HINT1/Hsp70 treatment induced regulatory NK cells ameliorating experimental autoimmune encephalomyelitis (EAE) course and CD4+ T cells proliferation. NK cells were isolated from mice treated with HINT1/Hsp70 and co-cultured with proteolipid protein (PLP)-stimulated CD4+ T cells isolated from EAE mice. Cell proliferation was assessed by thymidine uptake, cytotoxicity by lactate dehydrogenase (LDH) release assay and fluorescence activated cell sorting (FACS) analysis, protein expression by Western blot, mRNA by quantitative RT-PCR. Gene related to anergy in lymphocytes (GRAIL) expression was downregulated by specific siRNA and GRAIL overexpression was induced by pcDNA-GRAIL transfection. HINT1/Hsp70 pretreatment of EAE SJL/J mice ameliorated EAE course, suppressed PLP-induced T cell proliferation by enhancing T cell expression of GRAIL as GRAIL downregulation restored T cell proliferation. HINT1/Hsp70 treatment induced immunoregulatory NK cells which inhibited PLP-stimulated T cell proliferation not depending on T cell necrosis and apoptosis. This immunoregulatory NK cell function depended on NK cell expression of GRAIL as GRAIL downregulation diminished inhibition of NK cell suppression of T cell proliferation. Similarly GRAIL overexpression in NK cells induced their regulatory function. HINT1/Hsp70 treatment generated regulatory NK cells characterized by expression of GRAIL.

Stage-Specific Role of Interferon-Gamma in Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis

The role of interferon (IFN)-γ in multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), has remained as an enigmatic paradox for more than 30 years. Several studies attribute this cytokine a prominent proinflammatory and pathogenic function in these pathologies. However, accumulating evidence shows that IFN-γ also plays a protective role inducing regulatory cell activity and modulating the effector T cell response. Several innate and adaptive immune cells also develop opposite functions strongly associated with the production of IFN-γ in EAE. Even the suppressive activity of different types of regulatory cells is dependent on IFN-γ. Interestingly, recent data supports a stage-specific participation of IFN-γ in EAE providing a plausible explanation for previous conflicting results. In this review, we will summarize and discuss such literature, emphasizing the protective role of IFN-γ on immune cells. These findings are fundamental to understand the complex role of IFN-γ in the pathogenesis of these diseases and can provide basis for potential stage-specific therapy for MS targeting IFN-γ-signaling or IFN-γ-producing immune cells.

Positive or negative involvement of heat shock proteins in multiple sclerosis pathogenesis: an overview

Multiple sclerosis (MS) is the most diffuse chronic inflammatory disease of the central nervous system. Both immune-mediated and neurodegenerative processes apparently play roles in the pathogenesis of this disease. Heat shock proteins (HSPs) are a family of highly evolutionarily conserved proteins; their expression in the nervous system is induced in a variety of pathologic states, including cerebral ischemia, neurodegenerative diseases, epilepsy, and trauma. To date, investigators have observed protective effects of HSPs in a variety of brain disease models (e.g. of Alzheimer disease and Parkinson disease). In contrast, unequivocal data have been obtained for their roles in MS that depend on the HSP family and particularly on their localization (i.e. intracellular or extracellular). This article reviews our current understanding of the involvement of the principal HSP families in MS.

Antigen-specific immune reactions to ischemic stroke

Brain proteins are detected in the cerebrospinal fluid (CSF) and blood of stroke patients and their concentration is related to the extent of brain damage. Antibodies against brain antigens develop after stroke, suggesting a humoral immune response to the brain injury. Furthermore, induced immune tolerance is beneficial in animal models of cerebral ischemia. The presence of circulating T cells sensitized against brain antigens, and antigen presenting cells (APCs) carrying brain antigens in draining lymphoid tissue of stroke patients support the notion that stroke might induce antigen-specific immune responses. After stroke, brain proteins that are normally hidden from the periphery, inflammatory mediators, and danger signals can exit the brain through several efflux routes. They can reach the blood after leaking out of the damaged blood-brain barrier (BBB) or following the drainage of interstitial fluid to the dural venous sinus, or reach the cervical lymph nodes through the nasal lymphatics following CSF drainage along the arachnoid sheaths of nerves across the nasal submucosa. The route and mode of access of brain antigens to lymphoid tissue could influence the type of response. Central and peripheral tolerance prevents autoimmunity, but the actual mechanisms of tolerance to brain antigens released into the periphery in the presence of inflammation, danger signals, and APCs, are not fully characterized. Stroke does not systematically trigger autoimmunity, but under certain circumstances, such as pronounced systemic inflammation or infection, autoreactive T cells could escape the tolerance controls. Further investigation is needed to elucidate whether antigen-specific immune events could underlie neurological complications impairing recovery from stroke.

HINT1 peptide/Hsp70 complex induces NK-cell-dependent immunoregulation in a model of autoimmune demyelination

Heat shock proteins (Hsps) interact with the immune system and have been shown to contribute to immunoregulation. As efficient chaperones, Hsps bind many peptides and these complexes have many yet-to-be-clarified functions. We have shown that Hsp70 is complexed within the mouse CNS with peptide CLAFHDISPQAPTHFLVIPK derived from histidine triad nucleotide-binding protein-1 (HINT1₃₈₋₅₇/Hsp70). Only this complex, in contrast to other peptides complexed with Hsp70, was able to prevent experimental autoimmune encephalomyelitis (EAE) by induction of immunoregulatory mechanisms dependent on NK cells. Pretreatment of proteolipid protein peptide ₁₃₉₋₁₅₁(PLP₁₃₉₋₁₅₁) sensitized SJL/J mice with HINT1₃₈₋₅₇/Hsp70 prevented the development of EAE, suppressed PLP₁₃₉₋₁₅₁-induced T-cell proliferation, and blocked secretion of IL-17. HINT1₃₈₋₅₇ /Hsp70 stimulation of NK cells depended on synergistic activation of two NK-cell receptors, CD94 and NKG2D. NK cells with depleted CD94 or with blocked NKG2D did not inhibit PLP₁₃₉₋₁₅₁-induced spleen cell (SC) proliferation. The HINT1₃₈₋₅₇/Hsp70 complex enhanced surface expression of the NKG2D ligand-H60. Downstream signaling of CD94 and NKG2D converged at the adaptor proteins DAP10 and DAP12, and in response to HINT1₃₈₋₅₇ /Hsp70 stimulation, expression of DAP10 and DAP12 was significantly increased in NK cells. Thus, we have shown that the HINT1₃₈₋₅₇ /Hsp70 complex affects NK-cell function by enhancing NK-cell-dependent immunoregulation in the EAE model of autoimmune demyelination.

Gene therapy with mitochondrial heat shock protein 70 suppresses visual loss and optic atrophy in experimental autoimmune encephalomyelitis

PURPOSE

To rescue visual loss and optic neuropathy in experimental autoimmune encephalomyelitis (EAE).

METHODS

Encephalomyelitis was induced in mice that received intravitreal injections of AAV2-mtHSP70Flag or AAV2-Cox8-mCherry. Additional mice were injected with AAV2-Cox8-mCherry, but not sensitized for EAE. Visual function was assessed by pattern electroretinograms (PERG) at 1, 3, and 6 months post injection (MPI). Optical coherence tomography (OCT) evaluated the thickness of the inner plexiform layer + nerve fiber layers at 1, 3, and 6 MPI. Retinas and optic nerves (ONs) of mice euthanized 6 MPI were processed for light and electron microscopy. Expression of mtHSP70Flag in the retina and ONs was evaluated by RT-PCR, immunofluorescence, and Western blotting. The activities of respiratory complexes I and III, as well as mitochondrial protein import were quantitated.

RESULTS

Expression: immunofluorescence revealed punctate and perinuclear expression of mtHSP70Flag that colocalized with mitochondrial porin in thy1.2 labeled retinal ganglion cells (RGCs). Immunoblotting and RT-PCR confirmed mtHSP70Flag expression in the retina and ON. Rescue: treatment with mtHSP70Flag resulted in a 44% increase in PERG amplitude and less delays in latency relative to the EAE-mCherry group that also showed progressive inner retinal thinning. At 6 MPI, the almost 50% loss of RGCs and optic nerve axons in EAE mice was suppressed by mtHSP70Flag. In addition, retinas of EAE-mtHSP70Flag mice showed nearly complete rescue of complex I and III activities that was reduced by one-third in the EAE-mCherry retinas. Lastly, reductions in import of COX8-mCherry into mitochondria of mice sensitized for EAE improved by 30% with mtHSP70Flag gene therapy.

CONCLUSIONS

Mitochondrial HSP70 ameliorates mitochondrial dysfunction that culminates in irreversible visual loss and atrophy of the optic nerve in EAE suggesting that it may be useful to prevent irreversible disability in patients with optic neuritis and multiple sclerosis (MS).

Heat shock protein 70: roles in multiple sclerosis

Heat shock proteins (HSP) have long been considered intracellular chaperones that possess housekeeping and cytoprotective functions. Consequently, HSP overexpression was proposed as a potential therapy for neurodegenerative diseases characterized by the accumulation or aggregation of abnormal proteins. Recently, the discovery that cells release HSP with the capacity to trigger proinflammatory as well as immunoregulatory responses has focused attention on investigating the role of HSP in chronic inflammatory autoimmune diseases such as multiple sclerosis (MS). To date, the most relevant HSP is the inducible Hsp70, which exhibits both cytoprotectant and immunoregulatory functions. Several studies have presented contradictory evidence concerning the involvement of Hsp70 in MS or experimental autoimmune encephalomyelitis (EAE), the MS animal model. In this review, we dissect the functions of Hsp70 and discuss the controversial data concerning the role of Hsp70 in MS and EAE.

Natural killer cells and their receptors in multiple sclerosis

The immune system has crucial roles in the pathogenesis of multiple sclerosis. While the adaptive immune cell subsets, T and B cells, have been the main focus of immunological research in multiple sclerosis, it is now important to realize that the innate immune system also has a key involvement in regulating autoimmune responses in the central nervous system. Natural killer cells are innate lymphocytes that play vital roles in a diverse range of infections. There is evidence that they influence a number of autoimmune conditions. Recent studies in multiple sclerosis and its murine model, experimental autoimmune encephalomyelitis, are starting to provide some understanding of the role of natural killer cells in regulating inflammation in the central nervous system. Natural killer cells express a diverse range of polymorphic cell surface receptors, which interact with polymorphic ligands; this interaction controls the function and the activation status of the natural killer cell. In this review, we discuss evidence for the role of natural killer cells in multiple sclerosis and experimental autoimmune encephalomyelitis. We consider how a change in the balance of signals received by the natural killer cell influences its involvement in the ensuing immune response, in relation to multiple sclerosis.

Hsp70 and its molecular role in nervous system diseases

Heat shock proteins (HSPs) are induced in response to many injuries including stroke, neurodegenerative disease, epilepsy, and trauma. The overexpression of one HSP in particular, Hsp70, serves a protective role in several different models of nervous system injury, but has also been linked to a deleterious role in some diseases. Hsp70 functions as a chaperone and protects neurons from protein aggregation and toxicity (Parkinson disease, Alzheimer disease, polyglutamine diseases, and amyotrophic lateral sclerosis), protects cells from apoptosis (Parkinson disease), is a stress marker (temporal lobe epilepsy), protects cells from inflammation (cerebral ischemic injury), has an adjuvant role in antigen presentation and is involved in the immune response in autoimmune disease (multiple sclerosis). The worldwide incidence of neurodegenerative diseases is high. As neurodegenerative diseases disproportionately affect older individuals, disease-related morbidity has increased along with the general increase in longevity. An understanding of the underlying mechanisms that lead to neurodegeneration is key to identifying methods of prevention and treatment. Investigators have observed protective effects of HSPs induced by preconditioning, overexpression, or drugs in a variety of models of brain disease. Experimental data suggest that manipulation of the cellular stress response may offer strategies to protect the brain during progression of neurodegenerative disease.

Heat shock proteins HSP27 and HSP70 are present in the skin and are important mediators of allergic contact hypersensitivity

Proteomic analysis of murine skin has shown that a variety of heat shock proteins (HSPs) are constitutively expressed in the skin. Using murine allergic contact hypersensitivity as a model, we investigated the role of two heat shock proteins, HSP27 and HSP70, in the induction of cutaneous cell-mediated immune responses. Immunohistochemical examination of skin specimens showed that HSP27 was present in the epidermis and HSP70 was present in both the epidermis and dermis. Inhibition of HSP27 and HSP70 produced a reduction in the 1-fluoro-2,4-dinitrobenzene contact hypersensitivity response and resulted in the induction of Ag-specific unresponsiveness. Treatment of dendritic cell cultures with recombinant HSP27 caused in the up-regulation of IL-1beta, TNF-alpha, IL-6, IL-12p70, and IL-12p40 but not IL-23p19, which was inhibited when Abs to HSP27 were added. The 1-fluoro-2,4-dinitrobenzene-conjugated dendritic cells that had been treated with HSP27 had an increased capacity to initiate contact hypersensitivity responses compared with control dendritic cells. This augmented capacity required TLR4 signaling because neither cytokine production by dendritic cells nor the increased induction of contact hypersensitivity responses occurred in TLR4-deficient C3H/HeJ mice. Our findings indicate that a cascade of events occurs following initial interaction of hapten with the skin that includes increased activity of HSPs, their interaction with TLR4, and, in turn, increased production of cytokines that are known to enhance Ag presentation by T cells. The results suggest that HSPs form a link between adaptive and innate immunity during the early stages of contact hypersensitivity.

Beyond Stressed Self: Evidence for NKG2D Ligand Expression on Healthy Cells

The activity of cytotoxic lymphocytes is regulated by the opposing function of stimulatory and inhibitory cell surface receptors. According to the now classical model of Natural Killer (NK) cell activity, the ligands for inhibitory receptors are constitutively expressed on healthy cells but can be lost on infection and on malignant cells. Loss of inhibitory checks will then allow activating signals to predominate, forming the basis of 'missing self recognition'. Natural Killer Group 2D (NKG2D) is an important member of the cohort of activating receptors expressed on Natural Killer (NK) cells and subsets of T cells. Ligands for the NKG2D receptor comprise a diverse array of self-proteins structurally related to MHC class I molecules. Expression of NKG2D ligands can be induced in cells during infection with pathogens, tumourigenesis, and by stimuli such as DNA damage, oxidative stress, and heat shock. Consequently NKG2D has been widely described as participating in 'stressed self' or 'damaged self' recognition. However, a body of evidence has recently emerged to suggest that this intuitive model of NKG2D function may be an oversimplification. NKG2D ligand expression has now widely been reported on cells that could not be described as stressed or damaged. For example activated T cells can express NKG2D ligands, and constitutive expression of NKG2D ligands has been reported on normal myelomonocytic cells, dendritic cells, and epithelial cells of the gut mucosa. In this article we will review the literature suggesting that NKG2D may function to recognise non-stressed cells and discuss the role NKG2D ligands could be playing in apparently healthy cells.

HLA-DQ6 (DQB1*0601)-restricted T cells protect against experimental autoimmune encephalomyelitis in HLA-DR3.DQ6 double-transgenic mice by generating anti-inflammatory IFN-gamma

The human MHC class II genes are associated with genetic susceptibility to multiple sclerosis (MS), a chronic inflammatory demyelinating disease of the CNS of presumed autoimmune origin. These genes encode for proteins responsible for shaping immune response. The exact role of HLA-DQ and -DR genes in disease pathogenesis is not well-understood due to the high polymorphism, linkage disequilibrium, and heterogeneity of human populations. The advent of HLA class II-transgenic (Tg) mice has helped in answering some of these questions. Previously, using single-Tg mice (expressing the HLA-DR or -DQ gene), we showed that proteolipid protein (PLP)(91-110) peptide induced classical experimental autoimmune encephalomyelitis only in DR3.Abeta degrees mice, suggesting that DR3 (DRB1*0301) is a disease susceptible gene in the context of PLP. Human population studies have suggested that HLA-DQ6 (DQB1*0601) may be a protective gene in MS. To test this disease protection in an experimental model, we generated double-Tg mice expressing both HLA-DR3 and -DQ6. Introduction of DQ6 onto DR3-Tg mice led to a decrease in disease incidence on immunization with PLP(91-110) peptide indicating a dominant protective role of DQ6. This protective effect is due to high levels of IFN-gamma produced by DQ6-restricted T cells, which suppressed proliferation of encephalitogenic DR3-restricted T cells by inducing apoptosis. Our study indicates that DQ6 modifies the PLP(91-110)-specific T cell response in DR3 through anti-inflammatory effects of IFN-gamma, which is protective for experimental autoimmune encephalomyelitis. Thus, our double-Tg mouse provides a novel model in which to study epistatic interactions between HLA class II molecules in MS.

Deficient heat shock protein 70 response to stress in leukocytes at onset of type 1 diabetes

Type 1 diabetes is caused by the immune-mediated destruction of pancreatic beta cells. Animal models of the disease demonstrate an increased susceptibility of beta cells to immunological attacks due to their defective stress-responsiveness. To investigate the stress-responsiveness in human type 1 diabetes we analyzed the heat-inducibility of the dominant stress protein heat shock protein (Hsp)70 in diabetic patients at different disease stages. At diabetes-manifestation heat-induced Hsp70 levels in peripheral blood mononuclear cells (PBMC) reached only about 25% of the levels expressed by heat-treated PBMC from non-diabetic subjects (p<0.05). Heat-responsiveness improved with disease duration and was re-established at more than eight months after disease-manifestation. Hyperthermia-induced Hsp70 expression was decreased by the T-helper 1-associated cytokine interferon-gamma and increased by the T-helper 2-associated transforming growth factor-beta. We conclude that impaired cellular stress-responsiveness, aggravated by the inflammatory milieu at the onset of type 1 diabetes, contributes to disease manifestation.

Tat-Hsp70 protects dopaminergic neurons in midbrain cultures and in the substantia nigra in models of Parkinson's disease

Parkinson's disease is characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra. The heat-shock protein 70 (Hsp70) reduces protein misfolding and aggregation. It has been shown to protect cells against oxidative stress and apoptotic stimuli in various neurodegenerative disease models. To deliver Hsp70 across cellular membranes and into the brain, we linked it to a cell-penetrating peptide derived from the HIV trans-activator of transcription (Tat) protein. In vitro, Tat-Hsp70 transduced neuroblastoma cells and protected primary mesencephalic DA neurons and their neurites against MPP+-mediated degeneration. In vivo, the systemic application of cell-permeable Hsp70 protected DA neurons of the substantia nigra pars compacta against subacute toxicity of MPTP. Furthermore, Tat-Hsp70 diminished the MPTP induced decrease in DA striatal fiber density. Thus, we demonstrate that systemically applied Tat-Hsp70 effectively prevents neuronal cell death in in vitro and in vivo models of Parkinson's disease. The use of Tat-fusion proteins might therefore be a valuable tool to deliver molecular chaperones like Hsp70 into the brain and may be the starting point for new protective strategies in neurodegenerative diseases.

EAE tolerance induction with Hsp70-peptide complexes depends on H60 and NKG2D activity

Inflammation leads to induction of tissue stress conditions that might contribute to the generation of mechanisms limiting ongoing immune responses. We have shown previously that peptides derived from brain tissue of mice with experimental autoimmune encephalomyelitis (EAE) complexed with the chaperone heat shock protein 70 (Hsp70-pc) induce an NK-cell-dependent tolerance for subsequent EAE sensitization. We now present data that showed that the MHC class I-related glycoprotein H60 determines Hsp70-pc-induced EAE inhibition. Hsp70-pc led to significant and selective up-regulation of H60 expression in SJL/J mice, and Ab-blocking of H60 expression led to loss of EAE tolerance. Similarly, blocking of the NK cell receptor for H60, NKG2D, also reversed the Hsp70-pc-induced EAE inhibition. In contrast, in C57BL/6 mice H60 was not expressed, and Hsp70-pc-induced tolerance was not detected. The NK cell mediated Hsp70-pc-induced tolerance to EAE was dependent on modulation of dendritic cells function leading to diminished T cell reactivity to PLP. As, no increase of H60 expression on T cells from EAE mice immunized with PLP was detected, and no enhanced loss of CD3+ H60+ over CD3+ H60- cells in Hsp70-pc-induced EAE tolerance was found direct killing of H60+ PLP-reactive cells seems not to be involved in the Hsp70-pc-induced tolerance induction. We have provided evidence that Hsp70-pc-induced tolerance for EAE, mediated by NK cells, involves induction of H60 ligand and its interaction with NKG2D receptor. NK cells tolerization of EAE depends on altered dendritic cells activity leading to enhanced death of Ag reactive cells.

The role of natural killer cells in curbing neuroinflammation

Natural killer (NK) cells are evolutionarily early lymphocytes that lack antigen-specific receptors and, hence, are considered to be part of the innate immune system. The majority of research on NK cells has focused on their ability to lyse "target cells", generally identified by low or absent MHC Class I expression, such as tumor cells and virus infected cells. However, an alternative role of these leukocytes as regulators of adaptive (and potentially destructive) immune responses, in particular organ-specific autoimmune diseases, has been increasingly recognized. Here we discuss the growing body of evidence that NK cells limit damage in autoimmune demyelinating disease by inhibiting autoreactive T cell responses without harming resident neurons or glia.

Pharmacological induction of heat shock protein exerts neuroprotective effects in experimental intracerebral hemorrhage

Heat shock proteins (HSPs) are reported to reduce inflammation and apoptosis in a variety of brain insults. Geranylgeranylacetone (GGA), developed as an antiulcer in Japan, has been known to induce HSP70 and to exert cytoprotective effects. In this study, we investigated whether GGA, as a specific HSP inducer, exerts therapeutic effects in experimentally induced intracerebral hemorrhage (ICH). ICH was induced with male Sprague-Dawley rats via the collagenase infusion. GGA (800 mg/kg) was administered via oral tube according to various schedules of treatment. The treatment with GGA, beginning before the induction of ICH and continuing until day 3, showed the reduction of brain water content and the increased level of HSP70 protein, as compared to the treatment with vehicle, although GGA started after the induction of ICH or administered as a single dose before ICH failed to up-regulate HSP70 and to reduce brain edema. The rats treated with GGA exhibited better functional recovery than those treated with vehicle. In the pre- and post- treatment group, inflammatory cells and cell death in the perihematomal regions were found to have been decreased. The treatment of GGA inhibited the mRNA expression of MMP-9, uPA, IL-6 and MIP-1, with concomitant increment of eNOS and phosphorylated STAT3 and Akt after ICH. We demonstrated that GGA induced a reduction in the brain edema along with marked inhibitory effects on inflammation and cell death after ICH.