Periplaneta Americana (L.) extract activates the ERK/CREB/BDNF pathway to promote post-stroke neuroregeneration and recovery of neurological functions in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Periplaneta americana (L.) (PA) has been used in traditional Chinese medicine for thousands of years for the effect of invigorating blood circulation and removing blood stasis. Modern pharmacological research shown that PA extract exhibits promising effects in promoting wound healing and regeneration, as well as in brain diseases such as Parkinson's disease (PD). However, whether it is effective for neuroregeneration and neurological function recovery after stroke still unknown. AIM OF THE STUDY: This study aims to investigate the potential effect of PA extract to promote brain remodeling through the activation of endogenous neurogenesis and angiogenesis, in addition, preliminary exploration of its regulatory mechanism. METHODS: Firstly, BrdU proliferation assay and immunofluorescence (IF) staining were used to evaluate the effect of PA extract on the neurogenesis and angiogenesis in vitro and in vivo. Subsequently, the effects of PA extract on brain injury in stroke rats were assessed by TTC and HE. While mNSS score, adhesive removal test, rota-rod test, and morris water maze test were used to assess the impact of PA extract on neurological function in post-stroke rats. Finally, the molecular mechanisms of PA extract regulation were explored by RNA-Seq and western blotting. RESULTS: The number of BrdU+ cells in C17.2 cells, NSCs and BMECs dramatically increased, as well as the expression of astrocyte marker protein GFAP and neuronal marker protein Tuj-1 in C17.2 and NSCs. Moreover, PA extract also increased the number of BrdU+DCX+, BrdU+GFAP+, BrdU+CD31+ cells in the SGZ area of transient middle cerebral artery occlusion model (tMCAO) rats. TTC and HE staining revealed that PA extract significantly reduced the infarction volume and ameliorated the pathological damage. Behavioral tests demonstrated that treatment with PA extract reduced the mNSS score and the time required to remove adhesive tape, while increasing the time spent on the rotarod. Additionally, in the morris water maze test, the frequency of crossing platform and the time spent in the platform quadrant increased. Finally, RNA-Seq and Western blot revealed that PA extract increased the expression of p-ERK, p-CREB and BDNF. Importantly, PA extract mediated proliferation and differentiation of C17.2 and NSCs reversed by the ERK inhibitor SCH772984 and the BDNF inhibitor ANA-12, respectively. CONCLUSION: Our study demonstrated that PA extract promoted neurogenesis and angiogenesis by activating the CREB/ERK signaling pathway and upregulating BDNF expression, thereby recovering neurological dysfunction in post-stroke.

Facilitating Mitophagy via Pink1/Parkin2 Signaling Is Essential for the Neuroprotective Effect of ß-Caryophyllene against CIR-Induced Neuronal Injury.

Mitophagy is an important mechanism for maintaining mitochondrial homeostasis through elimination of damaged or dysfunctional mitochondria following cerebral ischemia-reperfusion (CIR) injury. ß-Caryophyllene (BCP) is a natural sesquiterpene compound found in the essential oil of plants and has been shown to ameliorate CIR injury. However, whether BCP protects neurons from CIR injury by activating mitophagy is still unclear, and the underlying mechanism remains unknown. In the present study, a mouse neuron HT-22 cell of oxygen-glucose deprivation/reoxygenation (OGD/R) and C57BL/6 male mouse of transient middle artery occlusion followed by 24 h reperfusion (MCAO/R) were established the model of CIR injury. Our results show that BCP remarkably protected against cell death and apoptosis induced by OGD/R, and decreased neurologic injury, infarct volume, and the injury of neurons in CA1 region on MCAO/R mice. In addition, BCP accelerated mitophagy by regulating expression of mitochondrial autophagy marker molecules and the mt-Atp6/Rpl13 ratio (reflecting the relative number of mitochondria), and promoting autophagosome formation compared with OGD/R and MCAO/R groups both in vitro and in vivo. Furthermore, this study revealed that BCP pre-treatment could activate the Pink1/Parkin2 signaling pathway, also with mitophagy activation. To explore the mechanisms, mitochondrial division inhibitor-1 (Mdivi-1) was used to investigate the role of BCP in CIR injury. We found that Mdivi-1 not only decreased BCP-induced facilitation of mitophagy, but also significantly weakened BCP-induced protection against OGD/R and MCAO/R models, which was consistent with levels of Pink1/Parkin2 signaling pathway. Taken together, these results suggest that facilitating mitophagy via Pink1/Parkin2 signaling is essential for the neuroprotective effect of BCP against CIR injury.

Differentially expressed genes induced by ß-caryophyllene in a rat model of cerebral ischemia-reperfusion injury.

Experimental studies have shown that ß-caryophyllene (BCP) improved neurological deficits of cerebral ischemia-reperfusion injury (CIRI) rats resulting from Middle Cerebral Artery Occlusion (MCAO). However, research on targets of BCP on CIRI has not been completed. In this study, the mRNA sequencing was used to distinguish various therapeutic multiple targets of BCP on CIRI. Differentially expressed genes (DEGs) were identified from RNA-seq analysis. CIRI induced up-regulated genes (CIRI vs. Sham) and BCP -induced down-regulated genes (BCP vs CIRI) were identified. Significant DEGs were identified only that expressed in each of all samples. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis of significant DEGs were determined by cluster Profiler. Protein interactive network (PPI) was analyzed using the String tool and Hub genes was identified by cytoHubba. Transcription factor (TF) regulatory network for the potential Hub genes was constructed. Western blot and ELISA were used to verified hub genes and relative inflammatory cytokines. After mRNA sequencing, a total of 411 DEGs were filtered based on the 2 series (CIRI vs. Sham and CIRI vs. BCP), with Pax1, Cxcl3 and Ccl20 are the most remarkable ones reversed by BCP. GO analysis was represented by DEGs involved in multiple biological process such as extra-cellular matrix organization, leukocyte migration, regulation of angiogenesis, reactive oxygen species metabolic process, etc. KEGG analysis showed that DEGs participated several signaling pathways including MAPK signaling pathway (rno04010), Cytokine-cytokine receptor interaction (rno04060), JAK-STAT signaling pathway (rno04630), and others. The protein-protein interaction (PPI) network consisted of 339 nodes and 1945 connections, and top ten Hub genes were identified by cytoHubba such as TIMP1, MMP-9, and STAT3. Subsequently, a TFs-miRNAs-targets regulatory network was established, involving 6 TFs, 5 miRNAs, and 10 hub genes, consisting of several regulated models such as Brd4 - rno-let-7e - Mmp9, Brd4 - rno-let-7i - Stat3, and Hnf4a- rno-let-7b -Timp1. Finally, western blot demonstrated that BCP could inhibit the increased TIMP1, MMP-9 and STAT3 expression in rat brains after I/R. ELISA represented that BCP could suppress inflammatory cytokines caused by CIRI and present anti-oxidative property. In conclusion, this study shows that the intervention of BCP can significantly reduce neurologic deficit, improve the cerebral ischemia, and a total of ten hub genes were found closely related to the treatment of BCP on CIRI. Prudent experimental validation suggests that the BCP might have the neuro-protective effects in CIRI by decreasing the expression of MMP-9 and TIMP-1, STAT3. In a sense, this study reveals that the MMP-9/TIMP-1 signaling pathway may be involved in the injury after CIRI and thus provides a new treatment strategy as well as a researching method for stroke.

[ß-caryophyllene alleviates cerebral ischemia/ reperfusion injury in mice by activating autophagy].

Cerebral ischemia-reperfusion(I/R) injury is an important cause of acute ischemic stroke. Timely elimination of damaged proteins and organelles by regulating autophagy during cerebral ischemia-reperfusion plays an important role in relieving brain damage. In order to investigate whether ß-caryophyllene(BCP) could protect neurons from cerebral I/R injury by regulating auto-phagy, C57 BL/6 J male mice were randomly divided into sham operation group, model group, and drug-administered group. After intra-gastric administration was given for 5 days, the middle cerebral artery occlusion(MCAO) model was established by suture method. Twenty four hours after surgery, the infarct volume and neurological function were assessed; the pathological changes of cortical tissue were observed by HE staining; Western blot was used to detect the expression of autophagy-related proteins beclin1, p62, LC3 B and apoptosis-related protein Bcl-2; immunofluorescence was used to observe the expression of LC3 B in the ischemic cortex. The autophagy of cortical tissue in the ischemic area was observed by transmission electron microscopy. The experimental results showed that as compared with the model group, the BCP pretreatment significantly reduced the neurological deficit, decreased the percentage of cerebral infarction volume, reduced the death of brain tissue cells in the ischemic area, up-regulated the expression of beclin1, LC3 B and Bcl-2 protein, down-regulated p62 protein expression, and significantly increased the number of autophagosomes in the cortical tissue of the ischemic area. It was finally determined that BCP could protect neurons from cerebral ischemia-reperfusion injury by activating autophagy.

Dendrobium Alkaloids Promote Neural Function After Cerebral Ischemia-Reperfusion Injury Through Inhibiting Pyroptosis Induced Neuronal Death in both In Vivo and In Vitro Models.

Pyroptosis is a newly identified lytic form of programmed cell death which is characterized by plasma membrane blebbing and rupture. Pyroptosis occurs in cerebral ischemia injury, and contributes to the activation and secretion of the inflammatory cytokines interleukin (IL)-1ß, IL-18, and IL-6. Previous reports have found that Dendrobium alkaloids (DNLA) can exert neuroprotective effects against oxygen-glucose deprivation/reperfusion (OGD/R) damage in vitro, but the mechanisms underlying these effects remain elusive. In this study, we investigated whether DNLA exerted therapeutic benefits against cerebral ischemia-reperfusion (CIR) damage via ameliorating pyroptosis and inflammation. OGD/R damage was induced in HT22 cells pretreated with DNLA (0.03, 0.3, or 3 mg/ml, 24 h prior to OGD/R), MCC950 (10 ng/ml, 1 h prior), and VX765 (10 ng/ml, 1 h prior). Neuronal apoptosis, necrosis, pyroptosis, and pathological changes were analyzed 24 h following OGD/R. Further to this, male C57/BL mice pretreated with different concentrations of DNLA (0.5 or 5 mg/kg, ip.) for 24 h and VX765 (50 mg/kg, ip., 1 h before CIR) underwent transient middle cerebral artery occlusion and reperfusion. We found that DNLA pretreatment resulted in a lower neurologic deficit score, a reduced infarct volume, fewer pyroptotic cells, and reduced levels of inflammatory factors 24 h after CIR. Furthermore, DNLA administration also reduced the levels of the pyroptosis-associated proteins Caspase-1 and gasdermin-D, particularly in the hippocampal CA1 region. Similar decreases were observed in the levels of the inflammatory factors IL-1ß, IL-6, and IL-18. OGD/R-associated ultrastructural damage was seen to improve following DNLA administration, likely due to the regulation of the tight junction protein Pannexin-1 by DNLA. Overall, these findings demonstrate that DNLA can protect against CIR damage through inhibiting pyroptosis-induced neuronal death, providing new therapeutic insights for CIR injury.

Bexarotene Attenuates Focal Cerebral Ischemia-Reperfusion Injury via the Suppression of JNK/Caspase-3 Signaling Pathway.

Apolipoprotein E (APOE) is implicated not only in chronic degenerative neurological diseases, such as Alzheimer's disease, but also in acute brain disorders, including traumatic brain injury. Bexarotene, a selective agonist of the retinoid X receptor, has been reported to enhance markedly the expression of APOE. Previous studies have indicated that bexarotene exerts neuroprotective effects in animal models of ischemic stroke by modulating the peripheral immune response and autophagy. However, the role of this drug in neuronal apoptosis and the potential mechanisms involved have yet to be elucidated. The present study employed transient middle cerebral artery occlusion (t-MCAO) as a model of acute cerebral ischemia/reperfusion injury. The experiments were performed in wild-type C57BL/6 mice and APOE gene knockout (APOE-KO) mice. After t-MCAO, mice received intraperitoneal injection of bexarotene (5 mg/kg) or an equal volume of the vehicle. The outcome measurements included neurological deficits, learning ability, spatial memory, infarct volume, histopathology, magnitude of apoptosis, and the level of expression of proteins of the JNK/caspase-3 signaling pathway. The obtained results demonstrated that bexarotene administration significantly improved neurological function, learning ability, and spatial memory in C57BL/6 mice, but not in APOE-KO mice. Infarct volume, tissue damage, neuronal apoptosis rate, and the expression of proteins involved in the JNK/caspase-3 signaling pathway were markedly increased after t-MCAO in both C57BL/6 and APOE-KO mice. Importantly, bexarotene treatment significantly ameliorated all these changes in C57BL/6, but not in APOE-KO mice. In conclusion, bexarotene markedly alleviates the neurological deficits, improves the histological outcome, and inhibits cell apoptosis in mice after t-MCAO. This effect is mediated, at least in part, by up-regulation of APOE. Thus, bexarotene may be a candidate drug for the treatment of cerebral ischemia patients.