Effect of genetic polymorphisms on the pharmacokinetics of gefitinib in healthy Chinese volunteers.

Gefitinib is the first-generation drug of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) metabolised by the cytochrome P450 and transported by P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2). In the present study, the pharmacokinetics of gefitinib in healthy Chinese volunteers was investigated and the effect of genetic polymorphisms on its variability was evaluted.Forty-five healthy volunteers were administered a single dose of gefitinib and the blood samples were used for quantifying the concentration of gefitinib and genotyping fifteen single-nucleotide polymorphisms of cytochrome P450 enzymes (CYP3A4, CYP3A5, CYP2D6, CYP2C9 and CYP2C19) and drug transporters (ABCB1 and ABCG2).CYP3A5*3 (rs776746) polymorphism showed a significant influence, with higher gefitinib AUC0-t in carrier of CC genotype than in CT/TT genotype (BH-adjusted p value <0.05). For CYP2C9*3 (rs1057910), significant differences in pharmacokinetics of gefitinib were detected between carriers of AA and AC genotypes, with higher AUC0-t, AUC0-∞ and Cmax in carrier of AC genotype than in AA gen-otype (BH-adjusted p value <0.05). No associations were found between SNPs in CYP3A4, CYP2D6, CYP2C19, ABCB1, ABCG2 and the pharmacokinetics of gefitinib.The SNPs in CYP3A5*3 (rs776746) and CYP2C9*3 (rs1057910) were found to be associated with altered gefitinib pharmacokinetics in healthy Chinese volunteers.

DL-3-n-butylphthalide ameliorates diabetes-associated cognitive decline by enhancing PI3K/Akt signaling and suppressing oxidative stress.

DL-3-n-Butylphthalide (DL-NBP), a small molecular compound extracted from the seeds of Apium graveolens Linn (Chinese celery), has been shown to exert neuroprotective effects due to its anti-inflammatory, anti-oxidative and anti-apoptotic activities. DL-NBP not only protects against ischemic cerebral injury, but also ameliorates vascular cognitive impairment in dementia patients including AD and PD. In the current study, we investigated whether and how DL-NBP exerted a neuroprotective effect against diabetes-associated cognitive decline (DACD) in db/db mice, a model of type-2 diabetes. db/db mice were orally administered DL-NBP (20, 60, 120 mg· kg-1· d-1) for 8 weeks. Then the mice were subjected to behavioral test, their brain tissue was collected for morphological and biochemical analyses. We showed that oral administration of DL-NBP significantly ameliorated the cognitive decline with improved learning and memory function in Morris water maze testing. Furthermore, DL-NBP administration attenuated diabetes-induced morphological alterations and increased neuronal survival and restored the levels of synaptic protein PSD95, synaptophysin and synapsin-1 as well as dendritic density in the hippocampus, especially at a dose of 60 mg/kg. Moreover, we revealed that DL-NBP administration suppressed oxidative stress by upregulating Nrf2/HO-1 signaling, and increased brain-derived neurotrophic factor (BDNF) expression by activating PI3K/Akt/CREB signaling in the hippocampus. These beneficial effects of DL-NBP were observed in high glucose-treated PC12 cells. Our results suggest that DL-NBP may be a potential pharmacologic agent for the treatment of DACD.

Regulation of Caveolin-1 and Junction Proteins by bFGF Contributes to the Integrity of Blood-Spinal Cord Barrier and Functional Recovery.

The blood-spinal cord barrier (BSCB) plays important roles in the recovery of spinal cord injury (SCI), and caveolin-1 is essential for the integrity and permeability of barriers. Basic fibroblast growth factor (bFGF) is an important neuroprotective protein and contributes to the survival of neuronal cells. This study was designed to investigate whether bFGF is beneficial for the maintenance of junction proteins and the integrity of the BSCB to identify the relations with caveolin-1 regulation. We examined the integrity of the BSCB with Evans blue dye and fluorescein isothiocyanate-dextran extravasation, measured the junction proteins and matrix metalloproteinases, and evaluated the locomotor function recovery. Our data indicated that bFGF treatment improved the recovery of BSCB and functional locomotion in contusive SCI model rats, reduced the expression and activation of matrix metalloproteinase-9, and increased the expressions of caveolin-1 and junction proteins, including occludin, claudin-5, p120-catenin, and ß-catenin. In the brain, in microvascular endothelial cells, bFGF treatment increased the levels of junction proteins, caveolin-1 small interfering RNA abolished the protective effect of bFGF under oxygen-glucose deprivation conditions, and the expression of fibroblast growth factor receptor 1 and co-localization with caveolin-1 decreased significantly, which could not be reversed by bFGF treatment. These findings provide a novel mechanism underlying the beneficial effects of bFGF on the BSCB and recovery of SCI, especially the regulation of caveolin-1.

bFGF Protects Against Blood-Brain Barrier Damage Through Junction Protein Regulation via PI3K-Akt-Rac1 Pathway Following Traumatic Brain Injury.

Many traumatic brain injury (TBI) survivors sustain neurological disability and cognitive impairments due to the lack of defined therapies to reduce TBI-induced blood-brain barrier (BBB) breakdown. Exogenous basic fibroblast growth factor (bFGF) has been shown to have neuroprotective function in brain injury. The present study therefore investigates the beneficial effects of bFGF on the BBB after TBI and the underlying mechanisms. In this study, we demonstrate that bFGF reduces neurofunctional deficits and preserves BBB integrity in a mouse model of TBI. bFGF suppresses RhoA and upregulates tight junction proteins, thereby mitigating BBB breakdown. In vitro, bFGF exerts a protective effect on BBB by upregulating tight junction proteins claudin-5, occludin, zonula occludens-1, p120-catenin, and ß-catenin under oxygen glucose deprivation/reoxygenation (OGD) in human brain microvascular endothelial cells (HBMECs). Both the in vivo and in vitro effects are related to the activation of the downstream signaling pathway, PI3K/Akt/Rac-1. Inhibition of the PI3K/Akt or Rac-1 by specific inhibitors LY294002 or si-Rac-1, respectively, partially reduces the protective effect of bFGF on BBB integrity. Overall, our results indicate that the protective role of bFGF on BBB involves the regulation of tight junction proteins and RhoA in the TBI model and OGD-induced HBMECs injury, and that activation of the PI3K/Akt /Rac-1 signaling pathway underlies these effects.

Gelatin Nanostructured Lipid Carriers Incorporating Nerve Growth Factor Inhibit Endoplasmic Reticulum Stress-Induced Apoptosis and Improve Recovery in Spinal Cord Injury.

Clinical translation of growth factor therapies faces multiple challenges; the most significant one is the short half-life of the naked protein. Gelatin nanostructured lipid carriers (GNLs) had previously been used to encapsulate the basic fibroblast growth factor to enhance the functional recovery in hemiparkinsonian rats. In this research, we comparatively study the enhanced therapy between nerve growth factor (NGF) loaded GNLs (NGF-GNLs) and NGF only in spinal cord injury (SCI). The effects of NGF-GNLs and NGF only were tested by the Basso-Beattie-Bresnahan (BBB) locomotion scale, inclined plane test, and footprint analysis. Western blot analysis and immunofluorescent staining were further performed to identify the expression of ER stress-related proteins, neuron-specific marker neuronal nuclei (NeuN), and growth-associated protein 43 (GAP43). Correlated downstream signals Akt/GSK-3ß and ERK1/2 were also analyzed with or without inhibitors. Results showed that NGF-GNLs, compared to NGF only, enhanced the neuroprotection effect in SCI rats. The ER stress-induced apoptosis response proteins CHOP, GRP78 and caspase-12 inhibited by NGF-GNL treatment were more obvious. Meanwhile, NGF-GNLs in the recovery of SCI are related to the inhibition of ER stress-induced cell death via the activation of downstream signals PI3K/Akt/GSK-3ß and ERK1/2.

Endoplasmic reticulum stress: relevance and therapeutics in central nervous system diseases.

Endoplasmic reticulum (ER) stress plays an important role in a range of neurological disorders, such as neurodegenation diseases, cerebral ischemia, spinal cord injury, sclerosis, and diabetic neuropathy. Protein misfolding and accumulation in the ER lumen initiate unfolded protein response in energy-starved neurons which are relevant to toxic effects. In neurological disorders, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, ER dysfunction is well recognized, but the mechanisms remain unclear. In stroke and ischemia, spinal cord injury, and amyotrophic lateral sclerosis, chronic activation of ER stress is considered as main pathogeny which causes neuronal disorders. By targeting components of these ER signaling responses, to explore clinical treatment strategies or new drugs in CNS neurological diseases might become possible and valuable in the future.