A New Role Discovered for IGTP: The Protective Effect of IGTP in ICH-Induced Neuronal Apoptosis

Echinocystic acid provides a neuroprotective effect via the PI3K/AKT pathway in intracerebral haemorrhage mice

Background

Echinocystic acid (EA), a natural extract from plants of Gleditsia sinensis Lam, exhibits anti-inflammatory, antioxidant and analgesic activities in different diseases. In this study, we explored the pharmacological effects of EA on intracerebral haemorrhage (ICH) in a collagenase-induced ICH mouse model.

Methods

EA (50 mg/kg, i.p. q.d) was injected after the establishment of ICH, and we measured the amount of degraded neurons in brain tissue with Fluoro-Jade C staining and the haemorrhagic injury volume with Luxol fast blue staining on day 3 after ICH. We also assessed animal behaviour by rotarod test, claw force test and modified neurological severity score (mNSS) score. The expression of apoptosis-related proteins such as Bcl-2, Bax and cleaved caspase-3 was analysed by Western blot.

Results

EA reduced both the death of neurons and the volume of haemorrhagic injury after ICH. The haemorrhage infarct volume of the ICH+EA group was 9.84%±3.32% lower than that in the ICH group of mice (P<0.01). The mNSS score of the ICH+EA treated group was 4.75±0.55 lower than that in the ICH group (P<0.01). With the administration of EA after ICH, the expression of Bcl-2 was upregulated while the Bax level was downregulated. The cleaved caspase-3 level was also significantly decreased. We further investigated the neuroprotective mechanism of EA. Western blot results showed that the expression of P-AKT increased after EA treatment and decreased after LY294002, an inhibitor of the PI3K/AKT pathway, treatment.

Conclusions

EA may provide neuroprotection via activation of the PI3K/AKT pathway. Given the safety of EA has been proven, further studies are required to investigate whether EA is a potential agent for the treatment of ICH.

Increased expression of HERPUD1 involves in neuronal apoptosis after intracerebral hemorrhage

Homocysteine-inducible endoplasmic reticulum stress-inducible ubiquitin-like domain member 1 protein (HERPUD1) is involved in endoplasmic reticulum stress response. Immense amounts of research showed HERPUD1 plays multiple roles in various models. In this work, we explored the role of HERPUD1 during the pathophysiological processes of intracerebral hemorrhage (ICH). Rat ICH model was established and verified by behavioral test. Western blot and immunohistochemistry revealed a significant up-regulation of HERPUD1 expression around the hematoma after ICH. Besides, the expression of cytochrome c (cyt c) and active caspase-3 increased accompanied to HERPUD1 expression. Double-labeled immunofluorescence indicated HERPUD1 mainly colocalized with neurons. Further study showed HERPUD1 silence brought about up-regulation of apoptosis markers including cyt c and active caspase-3 coupled with increased cell apoptosis in vitro model. All these findings suggested that HERPUD1 might play a protective role in ICH-induced neuronal apoptosis in rat models.

OTUB1 attenuates neuronal apoptosis after intracerebral hemorrhage

OTUB1 is a member of deubiquitinating enzymes, which was shown as a proteasome-associated DUB to be involved in the proteins Ub-dependent degradation. Previous studies have indicated that OTUB1 was expressed in brain. But its distribution and function in the brain remain unclear. In this study, we explored the roles of OTUB1 protein in the pathophysiology of intracerebral hemorrhage (ICH). From the results of Western blot, immunohistochemistry, and immunofluorescence, we found an obvious up-regulation of OTUB1 in neurons adjacent to the hematoma after ICH. Furthermore, we also found that the increase of OTUB1 expression was accompanied by the enhanced expression of Bax and active caspase-3, and decreased expression of Bcl-2 in the pathological process of rat ICH. What's more, our in vitro study, using OTUB1 RNA interference in PC12 cells, suggested that OTUB1 might exert its anti-apoptotic function in neuronal apoptosis. Therefore, OTUB1 may play a role in protecting the brain from secondary damage following ICH.