Trilobatin attenuates cerebral ischaemia/reperfusion-induced blood-brain barrier dysfunction by targeting matrix metalloproteinase 9: The legend of a food additive.

BACKGROUND AND PURPOSE: Blood-brain barrier (BBB) breakdown is one of the crucial pathological changes of cerebral ischaemia-reperfusion (I/R) injury. Trilobatin (TLB), a naturally occurring food additive, exerts neuroprotective effects against cerebral I/R injury as demonstrated in our previous study. This study was designed to investigate the effect of TLB on BBB disruption after cerebral I/R injury. EXPERIMENTAL APPROACH: Rats with focal cerebral ischaemia caused by transient middle cerebral artery occlusion were studied along with brain microvascular endothelial cells and human astrocytes to mimic BBB injury caused by oxygen and glucose deprivation/reoxygenation (OGD/R). KEY RESULTS: The results showed that TLB effectively maintained BBB integrity and inhibited neuronal loss following cerebral I/R challenge. Furthermore, TLB increased tight junction proteins including ZO-1, Occludin and Claudin 5, and decreased the levels of apolipoprotein E (APOE) 4, cyclophilin A (CypA) and phosphorylated nuclear factor kappa B (NF-κB), thereby reducing proinflammatory cytokines. TLB also decreased the Bax/Bcl-2 ratio and cleaved-caspase 3 levels along with a reduced number of apoptotic neurons. Molecular docking and transcriptomics predicted MMP9 as a prominent gene evoked by TLB treatment. The protective effects of TLB on cerebral I/R-induced BBB breakdown was largely abolished by overexpression of MMP9, and the beneficial effects of TLB on OGD/R-induced loss of BBB integrity in human brain microvascular endothelial cells and astrocyte co-cultures was markedly reinforced by knockdown of MMP9. CONCLUSIONS AND IMPLICATIONS: Our findings reveal a novel property of TLB: preventing BBB disruption following cerebral I/R via targeting MMP9 and inhibiting APOE4/CypA/NF-κB axis.

Icariside II mitigates myocardial infarction by balancing mitochondrial dynamics and reducing oxidative stress through the activation of Nrf2/SIRT3 signaling pathway.

Nuclear factor erythroid 2-related factor 2 (Nrf2)/silent mating type information regulation 2 homolog 3 (SIRT3) signaling pathway plays a pivotal role in regulating mitochondrial dynamics and oxidative stress, which are considered to be the principal pathogenesis of myocardial infarction (MI). Our previous study proved that pretreatment with icariside II (ICS II), a major active ingredient of Herbal Epimedii, exerts cardioprotective effect on MI, however, whether post-treatment with ICS II can alleviate MI and its underlying mechanism are still uncertain. Therefore, the present study was designed to investigate the therapeutic effect and the possible mechanism of ICS II on MI both in vivo and in vitro. The results revealed that post-treatment with ICS II markedly ameliorated myocardial injury in MI-induced mice and mitigated oxygen and glucose deprivation (OGD)-elicited cardiomyocyte injury. Further researches showed that ICS II promoted mitochondrial fusion, and suppressed mitochondrial fission and oxidative stress, which were achieved by facilitating the nuclear translocation of Nrf2 and activation of SIRT3. In summary, our findings indicate that ICS II mitigates MI-induced mitochondrial dynamics disorder and oxidative stress via activating the Nrf2/SIRT3 signaling pathway.

Icariside II Exerts Anti-Type 2 Diabetic Effect by Targeting PPARα/γ: Involvement of ROS/NF-κB/IRS1 Signaling Pathway.

Type 2 diabetes mellitus (T2DM) is a multisystem and complex metabolic disorder which is associated with insulin resistance and impairments of pancreatic ß-cells. Previous studies have shown that icariside II (ICS II), one of the main active ingredients of Herba Epimedii, exerts potent anti-inflammatory and anti-oxidative properties. In this study, we investigated whether ICS II exerted anti-T2DM profile and further explored its possible underlying mechanism both in vivo and in vitro. db/db mice were administered ICS II (10, 20, 40 mg·kg-1) for 7 weeks. We found that ICS II dose-dependently attenuated hyperglycemia and dyslipidemia, as well as inhibited hepatic steatosis and islet architecture damage in db/db mice. Moreover, ICS II not only dramatically reduced inflammatory cytokines and oxidative stress, but also up-regulated PPARα/γ protein expressions, phosphorylation of Akt, GSK3ß and IR, meanwhile, down-regulated phosphorylation of NF-κB(p65) and IRS1 in db/db mice. In palmitic acid (PA)-treated HepG2 or MIN6 cells, ICS II (5-20 µM) concentration-dependently promoted the cell viability via mediating PPARα/γ/NF-κB signaling pathway. PPARα/γ knockout by CRISPR-Cas9 system partly abolished the protective effects of ICS II on HepG2 or MIN6 cells following PA insults. These findings reveal that ICS II effectively confer anti-T2DM property by targeting PPARα/γ through mediation of ROS/NF-κB/IRS1 signaling pathway.

Icariside II, a Naturally Occurring SIRT3 Agonist, Protects against Myocardial Infarction through the AMPK/PGC-1α/Apoptosis Signaling Pathway.

Myocardial infarction (MI) refers to the death of cardiomyocytes triggered by a lack of energy due to myocardial ischemia and hypoxia, and silent mating type information regulation 2 homolog 3 (SIRT3) plays an essential role in protecting against myocardial oxidative stress and apoptosis, which are deemed to be the principal causes of MI. Icariside II (ICS II), one of the main active ingredients of Herbal Epimedii, possesses extensive pharmacological activities. However, whether ICS II can protect against MI is still unknown. Therefore, this study was designed to investigate the effect and possible underlying mechanism of ICS II on MI both in vivo and in vitro. The results showed that pretreatment with ICS II not only dramatically mitigated MI-induced myocardial damage in mice but also alleviated H9c2 cardiomyocyte injury elicited by oxygen and glucose deprivation (OGD), which were achieved by suppressing mitochondrial oxidative stress and apoptosis. Furthermore, ICS II elevated the phosphorylation level of adenosine monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) expression, thereby activating SIRT3. However, these protective effects of ICS II on MI injury were largely abolished in SIRT3-deficient mice, manifesting that ICS II-mediated cardioprotective effects are, at least partly, due to the presence of SIRT3. Most interestingly, ICS II directly bound with SIRT3, as reflected by molecular docking, which indicated that SIRT3 might be a promising therapeutic target for ICS II-elicited cardioprotection in MI. In conclusion, our findings illustrate that ICS II protects against MI-induced oxidative injury and apoptosis by targeting SIRT3 through regulating the AMPK/PGC-1α pathway.

Icariside II, a phosphodiesterase 5 inhibitor, attenuates cerebral ischaemia/reperfusion injury by inhibiting glycogen synthase kinase-3ß-mediated activation of autophagy.

BACKGROUND AND PURPOSE: Cerebral ischaemia/reperfusion causes exacerbated neuronal damage involving excessive autophagy and neuronal loss. The present study was designed to investigate the effect of icariside II, one of main active ingredients of Herba Epimedii on this loss and whether this is related to its PDE 5 inhibitory action. EXPERIMENTAL APPROACH: Focal cerebral ischaemia was induced in the rat by transient middle cerebral artery occlusion over 2 hr, followed by reperfusion with icariside II, 3-methylamphetamine or rapamycin. The effect of icariside II was determined measuring behaviour changes and the size of the infarction. The expressions of PDE 5, autophagy-related proteins and the level of phosphorylation of glycogen synthase kinase-3ß (GSK-3ß) were determined. Cultured primary cortical neurons were subjected to oxygen and glucose deprivation followed by reoxygenation in the presence and absence of icariside II. A surface plasmon resonance assay and molecular docking were used to explore the interactions of icariside II with PDE 5 or GSK-3ß. KEY RESULTS: Icariside II not only protected against induced ischaemic reperfusion injury in rats but also attenuated such injury in primary cortical neurons. The neuroprotective effects of icariside II on such injury were attributed to interfering with the PKG/GSK-3ß/autophagy axis by directly bounding to PDE 5 and GSK-3ß. CONCLUSIONS AND IMPLICATIONS: These findings indicate that icariside II attenuates cerebral I/R-induced injury via interfering with PKG/GSK-3ß/autophagy axis. This study raises the possibility that icariside II and other PDE 5 inhibitors maybe effective in the treatment ischaemia stroke.

Icariside II alleviates oxygen-glucose deprivation and reoxygenation-induced PC12 cell oxidative injury by activating Nrf2/SIRT3 signaling pathway.

Cerebral ischemia-reperfusion (I/R) injury is a key contributing factor to the pathogenic mechanisms involved in ischemic stroke. The present study was designed to explore the effects of icariside II (ICS II) on oxygen-glucose deprivation/reoxygenation (OGD/R)-induced PC12 cell oxidative injury. The results showed that ICS II ameliorated OGD/R-induced PC12 cell injury at the concentrations of 12.5, 25, and 50 µM, as evidenced by both the increase of cell viability and the decrease of LDH leakage from 33.96% ±â€¯0.48% to 16.78% ±â€¯0.78%, 13.12% ±â€¯0.17%, 12.96% ±â€¯0.10%, respectively. Moreover, ICS II not only attenuated the reactive oxygen species (ROS) from 212.2% ±â€¯5.45%, 168.6% ±â€¯5.29%, 148.7% ±â€¯9.37%, 142.7% ±â€¯7.76%, respectively, but also decreased the overproduction of mitochondrial ROS, as well as recovered the mitochondrial membrane potential (MMP) from 60.68% ±â€¯7.90% to 76.71% ±â€¯2.87%, 93.69% ±â€¯4.41%, 95.92% ±â€¯3.97%, respectively. Furthermore, OGD/R accelerated neuronal oxidative injury and apoptosis along with reduced nucleus-Nrf2, NQO-1, HO-1, Bcl-2 protein expressions, and increased Keap1, Bax and cleaved caspase-3 contents, whereas ICS II significantly reversed the abovementioned changes. Interestingly, ICS II also restrained the OGD/R-induced decrease in SIRT3 and IDH2 expressions. In conclusion, this study indicates that ICS II alleviates OGD/R-induced oxidative injury in PC12 cells, and its underlying mechanisms are due to the regulation of Nrf2/SIRT3 signaling pathway.

Effect of leukemia inhibitory factor on embryonic stem cell differentiation: implications for supporting neuronal differentiation.

AIM: Leukemia inhibitory factor (LIF), a pleiotropic cytokine, has been used extensively in the maintenance of mouse embryonic stem cell pluripotency. In this current work, we examined the effect of the LIF signaling pathway in embryonic stem (ES) cell differentiation to a neural fate. METHODS: In the presence of LIF (1000 U/mL), the production of neuronal cells derived from embryoid bodies (EB) was tested under various culture conditions. Inhibition of the LIF pathway was examined with specific inhibitors. The effects of cell apoptosis and proliferation on neural differentiation were examined. ES cell differentiation into three-germ layers was compared. RESULTS: Under various culture conditions, neuronal differentiation was increased in the presence of LIF. Blocking the LIF-activated STAT3 signaling pathway with specific inhibitors abolished the neuronal differentiation of ES cells, whereas inhibition of the LIF-activated MEK signaling pathway impaired the differentiation of ES cells toward a glial fate. LIF suppressed cell apoptosis and promoted cell proliferation during ES cell differentiation. LIF inhibited the differentiation of ES cells to both mesoderm and extraembryonic endoderm fates, but enhanced the determination of neural progenitors. CONCLUSION: These results suggest that LIF plays a positive role during the differentiation of ES cells into neuronal cells.

Knockdown of p53 by RNAi in ES cells facilitates RA-induced differentiation into muscle cells.

The p53 gene is widely expressed in embryo, tissues, and tumors, and its deficiency can rescue embryonic defects in certain genes null embryos. However, it is still poorly understood whether p53 is involved in myoblast and neuronal fate determination during embryogenesis. We established the ES cell clone in which p53 protein was persistently suppressed by stable expression of p53 RNAi, and GFP was expressed in a p53 RNAi transcription-independent manner. With the classical protocol in which the differentiation of ES cells into either neural or muscle cell is specifically modulated by different dosage retinoic acid (RA), we evaluated the function of p53 during myoblast and neuronal commitment. With RA treatment, silencing of p53 by RNAi in ES cells leads to dominant muscle cell production but lack of neuronal cell, indicating that p53 indeed plays a role during muscle and neuronal fate commitment. It thus provides a good model for investigating cross-talk between RA and p53 pathways during myogenesis and neurogenesis from ES cells.