IL-33 and its receptor ST2 play crucial roles in tissue repair and homeostasis. However, their involvement in optic neuropathy due to trauma and glaucoma remains unclear. Here, we report that IL-33 and ST2 were highly expressed in the mouse optic nerve and retina. Deletion of IL-33 or ST2 exacerbated retinal ganglion cell (RGC) loss, retinal thinning, and nerve fiber degeneration following optic nerve (ON) injury. This heightened retinal neurodegeneration correlated with increased neurotoxic astrocytes in Il33^-/- mice. In vitro, rIL-33 mitigated the neurotoxic astrocyte phenotype and reduced the expression of pro-inflammatory factors, thereby alleviating the RGC death induced by neurotoxic astrocyte-conditioned medium in retinal explants. Exogenous IL-33 treatment improved RGC survival in Il33^-/- and WT mice after ON injury, but not in ST2^-/- mice. Our findings highlight the role of the IL-33/ST2 axis in modulating reactive astrocyte function and providing neuroprotection for RGCs following ON injury.
Animals ; Interleukin-33/genetics* ; Interleukin-1 Receptor-Like 1 Protein/genetics* ; Optic Nerve Injuries/pathology* ; Retinal Ganglion Cells/pathology* ; Astrocytes/pathology* ; Mice ; Mice, Knockout ; Mice, Inbred C57BL ; Neuroprotection/physiology*

We have previously reported that Cystatin C (CysC) is a pivotal mediator in the neuroprotection induced by hyperbaric oxygen (HBO) preconditioning; however, the underlying mechanism and how CysC changes after stroke are not clear. In the present study, we demonstrated that CysC expression was elevated as early as 3 h after reperfusion, and this was further enhanced by HBO preconditioning. Concurrently, LC3-II and Beclin-1, two positive-markers for autophagy induction, exhibited increases similar to CysC, while knockdown of CysC blocked these elevations. As a marker of autophagy inhibition, p62 was downregulated by HBO preconditioning and this was blocked by CysC knockdown. Besides, the beneficial effects of preserving lysosomal membrane integrity and enhancing autolysosome formation induced by HBO preconditioning were abolished in CysC rats. Furthermore, we demonstrated that exogenous CysC reduced the neurological deficits and infarct volume after brain ischemic injury, while 3-methyladenine partially reversed this neuroprotection. In the present study, we showed that CysC is biochemically and morphologically essential for promoting autophagic flux, and highlighted the translational potential of HBO preconditioning and CysC for stroke treatment.
Animals ; Autophagy ; physiology ; Beclin-1 ; metabolism ; Brain ; metabolism ; pathology ; Brain Ischemia ; metabolism ; pathology ; therapy ; Cystatin C ; genetics ; metabolism ; Disease Models, Animal ; Gene Expression ; Gene Knockdown Techniques ; Hyperbaric Oxygenation ; Lysosomes ; metabolism ; pathology ; Male ; Microtubule-Associated Proteins ; metabolism ; Neurons ; metabolism ; pathology ; Neuroprotection ; physiology ; Oxygen ; therapeutic use ; Random Allocation ; Rats, Sprague-Dawley ; Rats, Transgenic ; Reperfusion Injury ; metabolism ; pathology ; therapy

OBJECTIVETo study the effect of astrocyte exosomes on hypoxic-ischemic neurons.

METHODSRat astrocytes were cultured in vitro, and differential centrifugation was used to obtain the exosomes from the cell supernatant. Transmission electron microscopy, Nanosight, and Western blot were used for the identification of exosomes. BCA method was used to measure the concentration of exosomes. Rat neurons were cultured in vitro and then divided into control group, exosome group, oxygen glucose deprivation (OGD) group, and OGD+exosome group (n=3 each). The OGD and OGD+exosome groups were cultured in glucose-free medium under the hypoxic condition. The exosome and OGD+exosome groups were treated with exosomes at a final concentration of 22 μg/mL. The control and OGD groups were given an equal volume of phosphate-buffered saline. ELISA was used to measure the level of lactate dehydrogenase (LDH) in neurons. The terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling was used to measure the apoptotic index of neurons.

RESULTSThe identification of exosomes showed that the exosomes extracted by differential centrifugation had the features of exosomes. Compared with the control and exosome groups, the OGD group had significant increases in LDH level and apoptotic index (P<0.05). Compared with the OGD group, the OGD+exosome group had significant reductions in LDH level and apoptotic index (P<0.05).

CONCLUSIONSThe exosomes from astrocytes have a protective effect on neurons with hypoxic-ischemic injury.

Animals ; Apoptosis ; Astrocytes ; physiology ; Cell Hypoxia ; Cells, Cultured ; Exosomes ; physiology ; Glucose ; deficiency ; Hydro-Lyases ; analysis ; Neuroprotection ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe whether adenosine Al receptor (Al R) mediated neuroprotection of Shenmai Injection (SI) on rat cerebral ischemia/reperfusion (I/R) injury.

METHODSThe focal cerebral I/R model was established by middle cerebral artery occlusion (MCAO). Totally 60 successfully modeled rats was divided into 5 groups according to randomized block principle, i.e., the model group, the SI group, the SI + AlR antagonist (1,3-dipropyl-8-cyclopentylxanthine, DPCPX) group, the AlR antagonist control group, and the dimethyl sulfoxide (DMSO) control group, 12 in each group. Besides, a sham-operation group was set up (n =12). SI at 15 mL/kg was peritoneally injected to mice in the SI group immediately after cerebral I/R. Equal volume of normal saline was injected to mice in the model group and the sham-operation group. DPCPX at 1 mg/mL was peritoneally injected to mice in the Al R antagonist control group 30 min before peritoneal injecting SI. DPCPX at 1 mg/kg and DMSO at 1 mL/kg were peritoneally injected to mice in the AlR antagonist control group and the DMSO control group 30 min immediately before cerebral I/R. Rats' neurobehavioral scores were assessed after 24 h reperfusion. The volume of cerebral infarction and Bcl-2 protein expression of cerebral infarction penumbra were also detected. Results Compared with the sham-operation group, neurobehavioral scores, the volume of cerebral infarction, and Bcl-2 protein expression increased (all P <0. 05). Compared with the model group, neurobehavioral scores and the volume of cerebral infarction obviously decreased, but Bcl-2 protein expression increased in the SI group (all P <0. 05). Compared with the SI group, neurobehavioral scores increased, the volume of cerebral infarction was obviously enlarged, and Bcl-2 protein expression was obviously reduced in the A1R antagonist control group (all P <0. 05).

CONCLUSIONSSI's neurobehavioral scores could be partially reversed in the Al R antagonist control group, the volume of cerebral infarction and Bcl-2 protein expression improved. AlR might possibly meditate neuroprotection of SI on MACO mire

Adenosine ; Animals ; Brain Ischemia ; drug therapy ; Drug Combinations ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Infarction, Middle Cerebral Artery ; Mice ; Neuroprotection ; physiology ; Neuroprotective Agents ; pharmacology ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Receptor, Adenosine A1 ; metabolism ; Reperfusion Injury ; drug therapy ; Xanthines

Neurodegenerative disease is characterized by progressive loss of neurons in specific brain regions that results in neuronal dysfunction of the central nervous system. Although the pathological mechanism is not fully established, the activation of glial cells mediated neuroinflammation appears to be involved. Heat shock protein 70 (HSP70) is originally described as intracellular chaperone, which plays an important role in protein quality control in cells. However, recent study showed that up-regulation of HSP70 had anti-inflammatory effects in the brain. HSP70 protected neurons from damage and improved neurological function by decreasing inflammatory response as indicated by inactivation of glial cells and inhibition of pro-inflammatory cytokine release. So it is of great significance to find new compounds targeting at HSP70 as neuroprotective agents to delay the progress of neurodegenerative disease. This review will focus on the role of HSP70 in neuroinflammation and the recent advances in using HSP70 as a target for the treatment of neurodegenerative disease.
Brain ; physiopathology ; Cytokines ; HSP70 Heat-Shock Proteins ; physiology ; Humans ; Inflammation ; pathology ; Neurodegenerative Diseases ; physiopathology ; Neurons ; pathology ; Neuroprotection ; Up-Regulation