Shenmai Injection Exerts Neuroprotective Functions by Down-regulating MicroRNA-19a in H 2 O 2 -induced PC12 Cells

Background: Acute ischemic stroke (AIS) and following reperfusion therapy-induced cerebral ischemia reperfusion (I/R) injury have been recognized as an important subject of cerebrovascular disease with high mortality. Oxidative stress is an important pathological process of cerebral I/R injury. microRNA-19a (miR-19a) is involved in I/R. As the organ protectant agent, Shenmai Injection (SMI) is widely used in the clinical treatment of cerebral infarction. Purpose: This study aims to explore whether SMI can reduce oxidative stress by regulating miR-19a, thereby treating I/R injury. Methods: The oxidative stress state of PC12 cells was induced by H2O2, and then the cells were cultured with SMI. The therapeutic effect of SMI was evaluated by detecting cellular superoxide dismutase (SOD), malondialdehyde (MDA) and other oxidative markers with the kit. Western blot, PCR, immunofluorescence and other techniques were used to elucidate the potential mechanism of SMI. Results: Cell viability assay results showed that SMI could improve the viability of PC12 cells stimulated by H2O2. Compared with the H2O2 group, after SMI treatment, the contents of MDA and reactive oxygen species (ROS) were significantly reduced, while the activity of SOD was significantly increased, and SMI could reduce apoptosis by increasing the content of adenosine 5'-triphosphate (ATP) in cells and enhancing the mitochondrial membrane potential (∆Ψm). Western blot and qRT-PCR results showed that these effects were partially achieved through the AMPK/Sirt1/PGC-1α pathway. The level of miR-19a was significantly increased in H2O2 group, and SMI could protect the cells by reducing miR-19a. Further investigated the target of miR-19a, and transfected cells with miR-19a mimic and inhibitor respectively. We found that AdipoR2 was a direct target of miR-19a, and miR-19a could inhibit AdipoR2/PI3K/Akt/mTOR pathway. Conclusion:SMI can activate AMPK/Sirt1/PGC-1α and AdipoR2/PI3K/Akt/mTOR pathways by reducing miR-19a levels, and protect PC12 cells stimulated by H2O2.

Exploring the Mechanism of Panax notoginseng Saponins against Alzheimer’s Disease by Network Pharmacology and Experimental Validation

Background. Panax notoginseng saponins (PNS) have been used for neurodegenerative disorders such as cerebral ischemia and Alzheimer’s disease (AD). Although increasing evidences show the neuron protective effects of PNS, the vital compounds and their functional targets remain elusive. To explore the potential functional ingredients of PNS for the AD treatment and their molecular mechanisms, an in vitro neuron injured model induced by Aβ was investigated, and the potential mechanism was predicted by network pharmacology approach and validated by molecular biology methods. Methods. Network pharmacology approach was used to reveal the relationship between ingredient-target disease and function-pathway of PNS on the treatment of AD. The active ingredients of PNS were collected from TCMSP, PubChem database, and literature mining in PubMed database. DrugBank and GeneCards database were used to predict potential targets for AD. The STRING database was performed to reveal enrichment of these target proteins, protein-protein interactions, and related pathways. Networks were visualized by utilizing Cytoscape software. The enrichment analysis was performed by the DAVID database. Finally, neuroprotective effect and predictive mechanism of PNS were investigated in an in vitro AD model established by Aβ25–35-treated PC12 cells. Results. An ingredient-target disease and function-pathway network demonstrated that 38 active ingredients were derived from PNS modulated 364 common targets shared by PNS and AD. GO and KEGG analysis, further clustering analysis, showed that mTOR signaling targets were associated with the neuroprotective effects of PNS. In Aβ-treated PC12 cells, PNS treatment improved neuroprotective effect, including mTOR inhibition and autophagy activation. Conclusions. Collectively, the protective effects of PNS on AD-neuron injury are related to the inhibition of mTOR and autophagy activation.

Huangdi Anxiao Attenuated High Glucose-Induced PC12 Cells Neurotoxicity via Inhibiting Apoptosis Pathway of Endoplasmic Reticulum Stress

Background Huangdi Anxiao (HDAX) is mainly used to treat diabetes and its complications for many years and has a remarkable curative effect. However, the improvement effect of HDAX in the diabetic cognitive dysfunction (DCD) model and the related mechanism is not clear. This study was aimed to explore the neuroprotective effects of HDAX and its possible mechanisms in DCD. Methods A DCD cell model was established by high glucose-induced PC12 cells, and the effect of HDAX on the cell viability was examined by MTT. Additionally, the expression of relevant genes and proteins in the apoptosis pathway of endoplasmic reticulum (ER) stress was detected. Results The results showed that HDAX increased cell viability, reduced GRP78, CHOP, Bax, procaspase-12, procaspase-9, procaspase-3 mRNA levels and GRP78, CHOP, Bax, Caspase-12, Caspase-9, Caspase-3 protein expressions, and decreased Bcl-2 mRNA level and protein expression. Conclusions These results suggested that HDAX had neuroprotective effects in the DCD cell model, which may be associated with the inhibition of the apoptosis pathway of ER stress.

Interactive Responses of Enkephalin, δ-opioid Receptor and Dopamine Receptor D1/D2 to Hypoxia and/or MPP+ Stress in PC12 Cells

Hypoxic/ischemic brain injury is a potential etiology of Parkinson’s disease (PD). There is evidence suggesting that the up-regulation of enkephalin, an endogenous opioid, in the midbrain may have a compensatory effect against Parkinson’s disease (PD) related motor symptoms. To explore the potential mechanism underlying this action, we investigated the effects of hypoxia and MPP+, a pathological inducer PD, on enkephalin, δ-opioid receptor (DOR, an enkephalin receptor), and prohormone convertases 1 and 2 (PC1/PC2) on in- vitro PD model of PC12 cells. We found that (1) short-term hypoxia could inducing cell protection by up-regulating the level of enkephalin, accompanied by the synergistic up-regulation of δ-opioid receptor (DOR) ; (2) a longer period of hypoxia or MPP+ insult accelerated the proteolysis of proenkephalin by up-regulating PC1/PC2 which might produce more active enkephalin and thus activating DOR for cell protection; (3) The levels of enkephalin and DOR decreased significantly after a prolonged hypoxia or MPP+ insult; and (4) a certain degree of hypoxia improved cell viability and enhance the transcription of dopamine D1/D2 receptorby increasing their mRNA level. Our findings suggest that hypoxia may induce an interactive reaction of enkephalin, DOR and dopamine receptor D1/D2, which is potentially beneficial for cell surviving to severe/prolonged hypoxia and PD condition.