SMND-309 promotes neuron survival through the activation of the PI3K/Akt/CREB-signalling pathway

Identification of hypoxia-related genes and exploration of their relationship with immune cells in ischemic stroke

Ischemic stroke (IS) is a major threat to human health, and it is the second leading cause of long-term disability and death in the world. Impaired cerebral perfusion leads to acute hypoxia and glucose deficiency, which in turn induces a stroke cascade response that ultimately leads to cell death. Screening and identifying hypoxia-related genes (HRGs) and therapeutic targets is important for neuroprotection before and during brain recanalization to protect against injury and extend the time window to further improve functional outcomes before pharmacological and mechanical thrombolysis. First, we downloaded the GSE16561 and GSE58294 datasets from the NCBI GEO database. Bioinformatics analysis of the GSE16561 dataset using the limma package identified differentially expressed genes (DEGs) in ischemic stroke using adj. p. values < 0.05 and a fold change of 0.5 as thresholds. The Molecular Signature database and Genecards database were pooled to obtain hypoxia-related genes. 19 HRGs associated with ischemic stroke were obtained after taking the intersection. LASSO regression and multivariate logistic regression were applied to identify critical biomarkers with independent diagnostic values. ROC curves were constructed to validate their diagnostic efficacy. We used CIBERSORT to analyze the differences in the immune microenvironment between IS patients and controls. Finally, we investigated the correlation between HRGs and infiltrating immune cells to understand molecular immune mechanisms better. Our study analyzed the role of HRGs in ischemic stroke. Nineteen hypoxia-related genes were obtained. Enrichment analysis showed that 19 HRGs were involved in response to hypoxia, HIF-1 signaling pathway, autophagy, autophagy of mitochondrion, and AMPK signaling pathway. Because of the good diagnostic properties of SLC2A3, we further investigated the function of SLC2A3 and found that it is closely related to immunity. We have also explored the relevance of other critical genes to immune cells. Our findings suggest that hypoxia-related genes play a crucial role in the diversity and complexity of the IS immune microenvironment. Exploring the association between hypoxia-related critical genes and immune cells provides innovative insights into the therapeutic targets for ischemic stroke.

The PI3K/AKT Pathway-The Potential Key Mechanisms of Traditional Chinese Medicine for Stroke

Stroke is associated with a high disability and fatality rate, and adversely affects the quality of life of patients and their families. Traditional Chinese Medicine (TCM) has been used effectively in the treatment of stroke for more than 2000 years in China and surrounding countries and regions, and over the years, this field has gleaned extensive clinical treatment experience. The Phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) pathway is important for regulation of cell migration, proliferation, differentiation, and apoptosis, and plays a vital role in vascularization and oxidative stress in stroke. Current Western medicine treatment protocols for stroke include mainly pharmacologic or mechanical thrombectomy to restore blood flow. This review collates recent advances in the past 5 years in the TCM treatment of stroke involving the PI3K/AKT pathway. TCM treatment significantly reduces neuronal damage, inhibits cell apoptosis, and delays progression of stroke via various PI3K/AKT-mediated downstream pathways. In the future, TCM can provide new perspectives and directions for exploring the key factors, and effective activators or inhibitors that affect occurrence and progression of stroke, thereby facilitating treatment.

Mechanism of SMND-309 against lung injury induced by chronic intermittent hypoxia

INTRODUCTION

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common sleep disorder that causes severe physiological disturbance. Evidence showed that OSAHS is an important associated comorbidity that can affect the survival of patients with pulmonary fibrosis. Until now, the potential mechanisms by which OSAHS accelerates the progression of lung fibrosis remain unclear. By constructing a pathological model of chronic intermittent hypoxia (CIH), the present study aimed to explore the pathological progress and potential mechanism of lung injury caused by OSAHS. Meanwhile, SMND-309 was given for treatment to evaluate its potential therapeutic role in CIH-induced lung injury.

METHODS

Mice were randomly divided into (C57BL/6 wild-type) WT+(room air) RA, WT + CIH, SMND-309 + RA, and SMND-309 + CIH groups. The WT + CIH and SMND-309 + CIH groups were exposed to CIH condition for 12 weeks, while the other groups were processed in normal oxygen at the same time. The SMND-309 + RA and SMND-309 + CIH groups were intraperitoneally injected with SMND-309 at the last week of the modeling period. After 12 weeks of treatment, three mice from each group were perfused through the heart. Lung tissues were isolated, fixed, sectioned, and stained with H&E, Masson, and immunofluorescence stain. The rest of the lung tissues were harvested for Western blot and ELISA assays.

RESULTS

CIH treatment increased the expression of pro-inflammatory factors (TNF-α and IL-6), resulting in lung tissue structure disorder, inflammatory cell infiltration, increased pulmonary capillary permeability, and pulmonary edema. The activation of the NF-κB signaling pathway played a crucial role in the process of inflammation. Noticeably, we observed M2 macrophage accumulation in the lung after CIH exposure, which promoted epithelial-mesenchymal transition (EMT) and pulmonary tissue fibrosis. ELISA assays showed the increased expression of TGF-β, IL-10, and IL-4 in the CIH group. SMND-309 inhibited pulmonary inflammation, reduced the accumulation of M2 macrophage, alleviated collagen deposition andlung damage.

CONCLUSION

CIH could induce chronic lung inflammation, promote the activation of M2 macrophages, trigger the occurrence of EMT, and accelerate the deposition of lung collagen, eventually leading to lung tissue damage. This study presents a possible explanation by which interstitial lung diseases, particularly idiopathic pulmonary fibrosis (IPF) with OSAHS, are usually associated with fast progress and poor prognosis. SMND-309 showed a good protective effect on CIH-induced lung damage.

Abnormal lipid droplets accumulation induced cognitive deficits in obstructive sleep apnea syndrome mice via JNK/SREBP/ACC pathway but not through PDP1/PDC pathway

The mechanisms of chronic intermittent hypoxia (CIH)-induced cognitive deficits remain unclear. Here, our study found that about 3 months CIH treatment induced lipid droplets (LDs) accumulation in hippocampal nerve and glia cells of C57BL/6 mice, and caused severe neuro damage including neuron lesions, neuroblast (NB) apoptosis and abnormal glial activation. Studies have shown that the neuronal metabolism disorders might contribute to the CIH induced-hippocampal impairment. Mechanistically, the results showed that pyruvate dehydrogenase complex E1ɑ subunit (PDHA1) and the pyruvate dehydrogenase complex (PDC) activator pyruvate dehydrogenase phosphatase 1 (PDP1) did not noticeable change after intermittent hypoxia. Consistent with those results, the level of Acetyl-CoA in hippocampus did not significantly change after CIH exposure. Interestingly, we found that CIH produced large quantities of ROS, which activated the JNK/SREBP/ACC pathway in nerve and glia cells. ACC catalyzed the carboxylation of Acetyl-CoA to malonyl-CoA and then more lipid acids were synthesized, which finally caused aberrant LDs accumulation. Therefore, the JNK/SREBP/ACC pathway played a crucial role in the cognitive deficits caused by LDs accumulation after CIH exposure. Additionally, LDs were peroxidized by the high level of ROS under CIH conditions. Together, lipid metabolic disorders contributed to nerve and glia cells damage, which ultimately caused behavioral dysfunction. An active component of Salvia miltiorrhiza, SMND-309, dramatically alleviated these injuries and improved cognitive deficits of CIH mice.

Tetramethylpyrazine induces the release of BDNF from BM-MSCs through activation of the PI3K/AKT/CREB pathway

Compelling evidences suggest that transplantation of bone marrow-derived mesenchymal stem cells (BM-MSCs) can be therapeutically effective for central nervous system (CNS) injuries and neurodegenerative diseases. The therapeutic effect of BM-MSCs mainly attributes to their differentiation into neuron-like cells which replace injured and degenerative neurons. Importantly, the neurotrophic factors released from BM-MSCs can also rescue injured and degenerative neurons, which plays a biologically pivotal role in enhancing neuroregeneration and neurological functional recovery. Tetramethylpyrazine (TMP), the main bioactive ingredient extracted from the traditional Chinese medicinal herb Chuanxiong, has been reported to promote the neuronal differentiation of BM-MSCs. This study aimed to investigate whether TMP regulates the release of neurotrophic factors from BM-MSCs. We examined the effect of TMP on brain-derived neurotrophic factor (BDNF) released from BM-MSCs and elucidated the underlying molecular mechanism. Our results demonstrated that TMP at concentrations of lower than 200 μM increased the release of BDNF in a dose-dependent manner. Furthermore, the effect of TMP on increasing the release of BDNF from BM-MSCs was blocked by inhibiting the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT)/cAMP-response element binding protein (CREB) pathway. Therefore, we concluded that TMP could induce the release of BDNF from BM-MSCs through activation of the PI3K/AKT/CREB pathway, leading to the formation of neuroprotective and proneurogenic microenvironment. These findings suggest that TMP possesses novel therapeutic potential to promote neuroprotection and neurogenesis through improving the neurotrophic ability of BM-MSCs, which provides a promising nutritional prevention and treatment strategy for CNS injuries and neurodegenerative diseases via the transplantation of TMP-treated BM-MSCs.

Neuroprotective effects of macamide from maca (Lepidium meyenii Walp.) on corticosterone-induced hippocampal impairments through its anti-inflammatory, neurotrophic, and synaptic protection properties

The present study aims to investigate the protective effects of N-(3-methoxybenzyl)-(9Z,12Z,15Z)-octadecatrienamide (M 18:3) on corticosterone-induced neurotoxicity. A neurotoxic model was established by subcutaneous injection of corticosterone (40 mg per kg bw) for 21 days. Depressive behaviors (the percentage of sucrose consumption, the immobility time in the forced swimming test, and the total distance in the open field test) were observed. The levels of the brain-derived neurotrophic factor, the contents of tumor necrosis factor-α and interleukin-6, and the numbers of positive cells of doublecortin and bromodeoxyuridine in the hippocampus were measured. The density of hippocampal neurons was calculated. The morphological changes of hippocampal neurons (the density of dendritic spines, the dendritic length, and the area and volume of dendritic cell bodies) were observed. The expression levels of synaptophysin, synapsin I, and postsynaptic density protein 95 were measured. Behavioral experiments showed that M 18:3 (5 and 25 mg per kg bw) could remarkably improve the depressive behaviors. The enzyme-linked immunosorbent assay showed that M 18:3 could considerably reduce hippocampal neuroinflammation and increase hippocampal neurotrophy. Nissl staining showed that M 18:3 could remarkably improve the corticosterone-induced decrease in the hippocampal neuron density. Immunofluorescence analysis showed that M 18:3 could considerably promote hippocampal neurogenesis. Golgi staining showed that M 18:3 could remarkably improve the corticosterone-induced changes in the hippocampal dendritic structure. Western blotting showed that M 18:3 could considerably increase the expression levels of synaptic-structure-related proteins in the hippocampus. In conclusion, the protective effects of M 18:3 may be attributed to the anti-inflammatory, neurotrophic, and synaptic protection properties.

Medicarpin Protects Cerebral Microvascular Endothelial Cells Against Oxygen-Glucose Deprivation/Reoxygenation-Induced Injury via the PI3K/Akt/FoxO Pathway: A Study of Network Pharmacology Analysis and Experimental Validation

Medicarpin, a pterocarpan class of naturally occurring phytoestrogen possesses various biological functions. However, the effect of medicarpin on oxygen-glucose deprivation-reoxygenation (OGD/R)-induced injury in human cerebral microvascular endothelial cells (HCMECs) remains largely unknown. Target genes of medicarpin were predicted from PharmMapper. Target genes of ischemic stroke were predicted from public databases GeneCards and DisGeNET. Kyoto Encyclopedia of Genes and Genomes pathway enrichment of the intersecting targets was analyzed via DAVID 6.8. Cell viability was evaluated using CCK-8 assay. Malondialdehyde content, superoxide dismutase activity, and glutathione level were detected using corresponding commercially available kits. Cell death was assessed by TUNEL assays. Expression of protein kinase B (Akt), phosphorylated-Akt, forkhead box protein O1, phosphorylated-FoxO1, FoxO3a, and phosphorylated-FoxO3a (p-FoxO3a) was detected by western blot analysis. The intersecting targets of medicarpin and ischemic stroke were significantly enriched in phosphatidylinositol 3-kinase (PI3K)/Akt and FoxO pathways. Medicarpina attenuated OGD/R-evoked viability inhibition, oxidative stress, and cell death in HCMECs. Additionally, medicarpin activated the PI3K/Akt and FoxO pathways in OGD/R-induced HCMECs. Inhibition of PI3K/Akt pathway abrogated the neuroprotective effect of medicarpin on OGD/R-induced injury and activation of FoxO pathway in HCMECs. In conclusion, medicarpin suppressed OGD/R-induced injury in HCMECs by activating PI3K/Akt/FoxO pathway.

Cyclic Strain and Electrical Co-stimulation Improve Neural Differentiation of Marrow-Derived Mesenchymal Stem Cells

The current study investigated the combinatorial effect of cyclic strain and electrical stimulation on neural differentiation potential of rat bone marrow-derived mesenchymal stem cells (BMSCs) under epidermal growth factor (EGF) and fibroblast growth factor 2 (FGF2) inductions in vitro. We developed a prototype device which can provide cyclic strain and electrical signal synchronously. Using this system, we demonstrated that cyclic strain and electrical co-stimulation promote the differentiation of BMCSs into neural cells with more branches and longer neurites than strain or electrical stimulation alone. Strain and electrical co-stimulation can also induce a higher expression of neural markers in terms of transcription and protein level. Neurotrophic factors and the intracellular cyclic AMP (cAMP) are also upregulated with co-stimulation. Importantly, the co-stimulation further enhances the calcium influx of neural differentiated BMSCs when responding to acetylcholine and potassium chloride (KCl). Finally, the phosphorylation of extracellular-signal-regulated kinase (ERK) 1 and 2 and protein kinase B (AKT) was elevated under co-stimulation treatment. The present work suggests a synergistic effect of the combination of cyclic strain and electrical stimulation on BMSC neuronal differentiation and provides an alternative approach to physically manipulate stem cell differentiation into mature and functional neural cells in vitro.

ERO1α inhibits cell apoptosis and regulates steroidogenesis in mouse granulosa cells

ER oxidoreduclin 1α (ERO1α), an oxidase that exists in the ER, participates in protein folding and secretion and inhibiting apoptosis, and regulates tumor progression, which is a novel factor of poor cancer prognosis. However, the other physiological functions of ERO1α remain undiscovered. Although our preliminary results of this study indicated that ERO1α revealed the robust expression in ovary, especially in granulosa cells, the role of ERO1α in follicular development is not well known. Therefore, the aims of the present study were to explore the role of ERO1α and the possible mechanisms in regulating cell apoptosis and steroidogenesis in ovarian granulosa cells. ERO1α was mainly localized in granulosa cells and oocytes in the adult ovary by immunohistochemistry. Western blot analysis showed that the expression of ERO1α was highest at oestrous stage during the estrous cycle. The effect of ERO1α on cell apoptosis and steroidogenesis was detected by transduction of ERO1α overexpression and knockdown lentiviruses into primary cultured granulosa cells. Flow cytometry analysis showed that ERO1α decreased granulosa cells apoptosis. Western bolt and RT-qPCR analysis found that ERO1α increased the ratio of BCL-2/BAX, and decreased BAD and Caspase-3 expression. ELISA analysis showed that ERO1α enhanced estrogen (E2) secretion. Western bolt and RT-qPCR analysis found that ERO1α increased StAR, CYP11A1, 3β-HSD, CYP17A1, and CYP19A1 expression, and decreased CYP1B1 expression. Furthermore, Western bolt analysis found that ERO1αincreased PDI and PRDX 4 expression, and activated the PI3K/AKT/mTOR signaling pathway through increasing the phosphorylation of AKT and P70 S6 kinase. In summary, these results suggested that ERO1α might play an anti-apoptotic role and regulate steroidogenesis in granulosa cells, at least partly, via activation of the PI3K/AKT/mTOR signaling pathway.

A Novel Compound YS-5-23 Exhibits Neuroprotective Effect by Reducing β-Site Amyloid Precursor Protein Cleaving Enzyme 1's Expression and H2O2-Induced Cytotoxicity in SH-SY5Y Cells

The abnormally accumulated amyloid-β (Aβ) and oxidative stress contribute to the initiation and progression of Alzheimer's disease (AD). β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is the rate-limiting enzyme for the production of Aβ. Furthermore, Aβ was reported to increase oxidative stress; then the overproduced oxidative stress continues to increase the expression and activity of BACE1. Consequently, inhibition of both BACE1 and oxidative stress is a better strategy for AD therapy compared with those one-target treatment methods. In the present study, our novel small molecule YS-5-23 was proved to possess both of the activities. Specifically, we found that YS-5-23 reduces BACE1's expression in both SH-SY5Y and Swedish mutated amyloid precursor protein (APP) overexpressed HEK293 cells, and it can also suppress BACE1's expression induced by H₂O₂. Moreover, YS-5-23 decreases H₂O₂-induced cytotoxicity including alleviating H₂O₂-induced apoptosis and loss of mitochondria membrane potential (MMP) because it attenuates the reactive oxygen species (ROS) level elevated by H₂O₂. Meanwhile, PI3K/Akt signaling pathway is involved in the anti-H₂O₂ and BACE1 inhibition effect of YS-5-23. Our findings indicate that YS-5-23 may develop as a drug candidate in the prevention and treatment of AD.

Protection of the Geum japonicum Thunb. var. chinense extracts against oxygen-glucose deprivation and re-oxygenation induced astrocytes injury via BDNF/PI3K/Akt/CREB pathway

Geum japonicum Tunb. var. chinense (GJ) is a traditional Chinese medicine usually used for the alleviation of dizziness and headache. Previous studies have reported that the GJ extracts could alleviate cerebral I/R injury by reducing apoptosis in vivo. To further elucidate the positive role and underlying mechanism of the GJ extracts in cerebral I/R injury, the current study investigated the effects of the GJ extracts on oxygen-glucose deprivation and re-oxygenation (OGD/R)-induced astrocytes injury in light of BDNF/PI3K/Akt/CREB signaling pathway with seropharmacological method. In the present study, the LC-MS profiling of the GJ extracts, obtain by reflux extraction, led to the identification of three possible active components were 5-desgalloylstachyurin, tellimagrandin II (TG II) and 3,4,5-Trihydroxybenzaldehyde (THBA). Drug-containing serum was collected from rats given different doses of the GJ extracts (0, 1.75 g/kg, 7 g/kg). Data indicated that the GJ extracts could increase the cell viability and decrease apoptosis and the expression of glial fibrillary acidic protein (GFAP) in OGD/R-induced astrocytes. In addition, the detection of apoptosis-related factors showed that the GJ extracts could obviously increase the expression of Bcl-2 and reduce the expression of Bax, Caspase-3 and cleaved-Caspase-3. Furthermore, the GJ extracts markedly increased the expression of BDNF, TrkB, PI3K, p-Akt and p-CREB. All these effects of the GJ extracts could be significantly reversed by LY294002, an inhibitor of PI3K. These data indicated that the GJ extracts could protect astrocytes against OGD/R-induced injury by inhibiting astrocytes reactivity and apoptosis, owing to the activation of the BDNF/PI3K/Akt/CREB pathway. The results support the application of the GJ extracts in the treatment of ischemic stroke and other ischemic encephalopathy.

Involvement of chronic unpredictable mild stress-induced hippocampal LRP1 up-regulation in microtubule instability and depressive-like behavior in a depressive-like adult male rat model

Low-density lipoprotein receptor-related protein 1 (LRP1) and tau play an important role in developing Alzheimer's disease. This study aimed to explore the involvement of LRP1 in microtubule dynamic and depressive-like behavior in a depressive-like rat model. It also investigated whether fluoxetine blocked the change induced by chronic unpredictable mild stress (CUMS). Sprague-Dawley rats (200-250 g) were exposed to CUMS and fluoxetine for 4 weeks respectively. The body weight was determined, and behavior tests, including sucrose preference test, forced swimming test and open field test were performed. Western blot analysis was conducted to determine the protein levels of LRP1, tubulin, Acet-tub, Tyr-tub and PI3K/Akt/GSK-3β. Real-time quantitative polymerase chain reaction was used for mRNA expression levels of LRP1. Immunohistochemical staining was applied for LRP1 and immunofluorescence staining for the co-location of p-tau (404,262) and Acet-tub. The CUMS group presented a decreased body weight and depressive-like behavior, which was improved by fluoxetine. The protein and mRNA expression levels of LRP1 were elevated in the CUMS group. The levels of Acet-tub increased following CUMS, accompanied by elevated levels of p-tau (404,262). The binding of p-tau and Acet-tub significantly decreased in depressive-like rats, and fluoxetine attenuated microtubule instability. Finally, the inhibition of CUMS-induced PI3K/Akt activated GSK-3β, and fluoxetine reversed the change in the signaling pathway. Hence, LRP1 might impair the microtubule dynamics accompanied by depressive-like behavior via the PI3K/ Akt /GSK3β pathway in adult depressive-like rats, and hippocampal LRP1 might be involved in the development of depression.

The neuroprotective effect and action mechanism of polyphenols in diabetes mellitus-related cognitive dysfunction

BACKGROUND

Diabetes mellitus (DM) is a complex and prevalent metabolic disorder worldwide. Strong evidence has emerged that DM is a risk factor for the accelerated rate of cognitive decline and the development of dementia. Though traditional pharmaceutical agents are efficient for the management of DM and DM-related cognitive decrement, long-term use of these drugs are along with undesired side effects. Therefore, tremendous studies have focused on the therapeutic benefits of natural compounds at present. Ample evidence exists to prove that polyphenols are capable to modulate diabetic neuropathy with minimal toxicity and adverse effects.

PURPOSE

To describe the benefits and mechanisms of polyphenols on DM-induced cognitive dysfunction. In this review, we introduce an updated overview of associations between DM and cognitive dysfunction. The risk factors as well as pathological and molecular mechanisms of DM-induced cognitive dysfunction are summarized. More importantly, many active polyphenols that possess preventive and therapeutic effects on DM-induced cognitive dysfunction and the potential signaling pathways involved in the action are highlighted.

CONCLUSIONS

The therapeutic effects of polyphenols on DM-related cognitive dysfunction pave a novel way for the management of diabetic encephalopathy.

Protective effects of macamides from Lepidium meyenii Walp. against corticosterone-induced neurotoxicity in PC12 cells

Maca has attracted considerable attention owing to its neuroprotective effects in vitro and vivo. Macamides, a series of nonpolar and long-chain fatty acid N-benzylamides, are considered unique constituents in maca. This study investigated the protective effects of ethanol extracts of maca (EEM) and macamides on corticosterone-induced (CORT) neurotoxicity in rat pheochromocytoma (PC12) cells. CORT reduced cell viability and increased LDH release, intracellular ROS levels, and MMP decline rate, and induced mitochondrial apoptosis. However, pretreatment with EEM and macamides ameliorated CORT-induced neurotoxicity. EEM increased the cell viability and reduced the LDH release. M 18:1, M 18:2, and M 18:3 increased cell viability and reduced LDH release and intracellular ROS generation. M 18:2 and M 18:3 inhibited MMP reduction and reduced the Bax/Bcl-2 ratios. M 18:1 reduced the intracellular ROS without affecting other factors. Moreover, M 18:3 prevented CORT-induced mitochondrial apoptosis, restrained the expression levels of pro-apoptotic proteins, namely, Bax, cytochrome C, cleaved-caspase-3, and cleaved-PARP, and increased the expression levels of Bcl-2. In addition, M 18:3 increased Akt phosphorylation and the ability of M 18:3 to protect against CORT-induced cytotoxicity was remarkably reduced by LY294002, a PI3K phosphorylation inhibitor. M 18:3 also elevated the phosphorylation of CREB and activated the BDNF protein levels in CORT-induced PC12 cells. In conclusion, macamides, especially M 18:3, exert protective effects on CORT-induced PC12 cells. The cellular mechanism of M 18:3 against CORT-induced cytotoxicity may involve inhibition of mitochondrial apoptosis, and activation of Akt and CREB phosphorylation. Overall, macamides may potentially treat neuronal damage induced by CORT.

Neuroprotection of macamides is probably associated with inhibition of the mitochondrial apoptotic and the activation of the phosphorylation of Akt and CREB.

ERK1/2 and JNK signaling synergistically modulate mitogenic effect of fibroblast growth factor 2 on liver cell

Proliferation of the adult hepatocyte population represents a central feature of tissue regeneration after liver injury and resection. This process could be driven by a diverse range of mitogens, such as hepatocyte growth factor (HGF) and fibroblast growth factor (FGF). Among FGF family, FGF2 is closely related to wound repair and cell proliferation. FGF2 does function in the process of angiogenesis in regenerating liver, while fewer reports are concerned with the impact and underlying mechanism of FGF2 on liver cell proliferation. To this end, an immortalized human normal hepatocyte L02 and mouse primary hepatocytes were exposed to FGF2 in this study. We demonstrate that FGF2 significantly enhances liver cell proliferation. Treatment with FGF2 obviously increases the phosphorylation level of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and c-Jun N-terminal kinase (JNK). Activity inhibition or expression down-regulation prove that both ERK1/2 and JNK signaling are required for FGF2-mediated effect on liver cell proliferation. Interestingly, interfering of ERK1/2 signaling results in marked decrease of JNK activation under FGF2 treatment, and JNK signaling is also involved in regulation of FGF2-induced ERK1/2 activation, suggesting that cross-talk between ERK1/2 and JNK signaling is important for FGF2 mitogenic activity. Both ERK1/2 and JNK signal via CREB to function in proliferation impact of FGF2 on liver cells. Taken together, this study reveals that ERK and JNK pathways synergistically regulate FGF2-induced liver cell proliferation via phosphorylating CREB, which will contribute to the understanding of FGF2 impact on liver cell proliferation and liver regeneration.

Diterpene ginkgolides protect against cerebral ischemia/reperfusion damage in rats by activating Nrf2 and CREB through PI3K/Akt signaling

Diterpene ginkgolides meglumine injection (DGMI) is a therapeutic extract of Ginkgo biloba L, which has been used for the treatment of cerebral ischemic stroke in China. Ginkgolides A, B and C are the main components of DGMI. This study was designed to investigate the neuroprotective effects of DGMI components against ischemic stroke in vivo and in vitro. Acute cerebral ischemic injury was induced in rats by occlusion of the middle cerebral artery (MCA) for 1.5 h followed by 24 h reperfusion. The rats were treated with DGMI (1, 3 and 10 mg/kg, iv) at the onset of reperfusion and 12 h after reperfusion. Administration of DGMI significantly decreased rat neurological deficit scores, reduced brain infarct volume, and induced protein kinase B (Akt) phosphorylation, which prompted the nuclear translocation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and phosphorylation of the survival regulatory protein cyclic AMP-responsive element binding protein (CREB). Nrf2 activation led to expression of the downstream protein heme oxygenase-1 (HO-1). In addition, PC12 cells were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) in vitro, treatment with DGMI (1, 10 and 20 μg/mL) or ginkgolides A, B or C (10 μmol/L for each) significantly reduced PC12 cell death and increased phosphorylation of Akt, nuclear translocation of Nrf2 and activation of CREB. Activation of Nrf2 and CREB could be reversed by co-treatment with a phosphoinositide-3-kinase (PI3K) inhibitor LY294002. These observations suggest that ginkgolides act as novel extrinsic regulators activating both Akt/Nrf2 and Akt/CREB signaling pathways, protecting against cerebral ischemia/reperfusion (I/R) damage in vivo and in vitro.

RP105 protects PC12 cells from oxygen‑glucose deprivation/reoxygenation injury via activation of the PI3K/AKT signaling pathway

Radioprotective 105 kDa protein (RP105) has been reported to produce favorable outcomes in various cardiovascular disorders via a toll‑like receptor 4‑dependent or ‑independent manner. However, whether RP105 exerts neuroprotective effects against oxygen‑glucose deprivation (OGD)/reoxygenation (OGD/R) injury remains to be elucidated. In the present study, the PC12 neuronal cell line was exposed to 4 h of OGD followed by 24 h of reoxygenation. Adenoviral vectors encoding RP105 were utilized to upregulate the level of RP105 in PC12 cells prior to OGD/R induction. The results demonstrated that OGD/R reduced the expression of RP105 at the mRNA and protein levels. The overexpression of RP105 significantly reversed OGD/R‑induced neuronal injuries, as demonstrated by the reduced release of lactate dehydrogenate and enhanced cellular viability, in addition to decreased inflammation, apoptosis and reactive oxygen species. The mechanistic evaluations indicated that the neuroprotective functions of RP105 were, in part, a result of activation of the phosphatidylinositol 3‑kinase (PI3K)/protein kinase B (AKT) pathway. In addition, elimination of the PI3K/AKT axis via the use of a pharmacological inhibitor inhibited the OGD/R‑inhibitory effects induced by the overexpression of RP105. Taken together, RP105 protected PC12 cells from OGD/R injury through promotion of the PI3K/AKT pathway; therefore, the RP105‑PI3K‑AKT axis may provide a novel therapeutic target for the prevention of cerebral ischemia/reperfusion injury.

Botanicals as Modulators of Neuroplasticity: Focus on BDNF

The involvement of brain-derived neurotrophic factor (BDNF) in different central nervous system (CNS) diseases suggests that this neurotrophin may represent an interesting and reliable therapeutic target. Accordingly, the search for new compounds, also from natural sources, able to modulate BDNF has been increasingly explored. The present review considers the literature on the effects of botanicals on BDNF. Botanicals considered were Bacopa monnieri (L.) Pennell, Coffea arabica L., Crocus sativus L., Eleutherococcus senticosus Maxim., Camellia sinensis (L.) Kuntze (green tea), Ginkgo biloba L., Hypericum perforatum L., Olea europaea L. (olive oil), Panax ginseng C.A. Meyer, Rhodiola rosea L., Salvia miltiorrhiza Bunge, Vitis vinifera L., Withania somnifera (L.) Dunal, and Perilla frutescens (L.) Britton. The effect of the active principles responsible for the efficacy of the extracts is reviewed and discussed as well. The high number of articles published (more than one hundred manuscripts for 14 botanicals) supports the growing interest in the use of natural products as BDNF modulators. The studies reported strengthen the hypothesis that botanicals may be considered useful modulators of BDNF in CNS diseases, without high side effects. Further clinical studies are mandatory to confirm botanicals as preventive agents or as useful adjuvant to the pharmacological treatment.