Zhiying Hu

Triptolide Down-regulates COX-2 Expression and PGE2 Release by Suppressing the Activity of NF-κB and MAP kinases in Lipopolysaccharide-treated PC12 Cells

As an active compound extracted from the Chinese herb Tripterygium wilfordii, triptolide (TP) was demonstrated to have potent antiinflammatory and immunosuppressive properties in previous studies. Recently, it has been shown that TP prevented the loss of dopaminergic neurons in the substantia nigra of rats in a model of Parkinsons disease, but little is known about the precise neuroprotective mechanism of TP. This study was designed to elucidate whether the neuroprotective effect of TP is partially based on its direct inhibition of inflammatory molecules by investigating the effects of TP on the expression of cyclooxygenase (COX)‐2 and prostaglandin E2 (PGE2) related to the nuclear factor (NF)‐κB pathway in lipopolysaccharide (LPS)‐stimulated PC12 cells. The activation of related upstream molecules such as NF‐κB, P38, extracellular signal‐regulated kinase (ERK)1/2, and beta‐alanyl‐alpha‐ketoglutarate transaminase (AKT), in PC12 cells were investigated by real time polymerase chain reaction (PCR), western blotting and enzyme‐linked immunosorbent assay (ELISA). Our results showed that TP directly inhibited the expression of both mRNA and protein of COX‐2 (p < 0.01), decreased PGE2 production (p < 0.01) in a dose‐dependent manner, down‐regulated NF‐κB activity (p < 0.01), and significantly inhibited the phosphorylation of p38, ERK1/2 (p42/p44) and AKT in PC12 cells after LPS challenge. This suggests that the neuroprotective effects of TP may be partially mediated by direct inhibition of the expression of COX‐2, activation of NF‐κB, and phosphorylation of p38, ERK1/2 (p42/p44) and AKT proteins of neuronal cells. Copyright

Exogenous progesterone: a potential therapeutic candidate in CNS injury and neurodegeneration.

The role of progesterone (PROG) in the regulation of reproductive behavior is well understood, but a large and growing body of evidence indicates that this hormone also exerts neuroprotective effects on the central nervous system (CNS), i.e. in spinal cord injuries, traumatic brain injuries and in the age-related pathological process. Its neuroprotective actions, now well documented by experimental studies, make it a particularly promising therapeutic agent for neuroinjury and neurodegenerative diseases. The purpose of this article is to review recent preclinical and epidemiological evidences that exogenous administration of PROG or its metabolites plays an important role in the CNS. The diverse signaling mechanisms and the dose- dependent neuroprotective actions of PROG are also summarized. Awareness of the pleiotropic effects of PROG may open a novel perspective for the treatment of injuries and diseases in the nervous system. PROG could be produced in the brain by neurons and glial cells in the CNS of both male and female. Laboratories around the world have reported that administering relatively large doses of PROG during the first few hours or even days after injury significantly limits CNS damage, reduces loss of neuronal tissue and improves functional recovery. PROG appears to exert its protective effects by protecting or rebuilding the blood-brain barrier, decreasing the development of cerebral edema, down-regulating the inflammatory cascade, and limiting cellular necrosis and apoptosis. All these are plausible mechanisms of neuroprotection.

Autophagy Upregulation and Apoptosis Downregulation in DAHP and Triptolide Treated Cerebral Ischemia

It has previously been demonstrated that ischemic stroke activates autophagy pathways; however, the mechanism remains unclear. The aim of this study is to further investigate the role that autophagy plays in cerebral ischemia. 2, 4-diamino-6-hydroxy-pyrimidine (DAHP), for its nitric oxide synthase (NOS) inhibiting neuroprotective effect, and triptolide (TP), for its anti-inflammatory property, were selected to administer pre middle cerebral artery occlusion (MCAO). The drugs were administered 12 hours prior to MCAO. Both magnetic resonance imaging (MRI) and 2, 3, 5-triphenyltetrazolium chloride (TTC) staining showed that the drugs reduce the area of infarction. Immunoblotting analysis revealed increases in Beclin-1 and myeloid cell leukelia-1(Mcl-1) in treated rats. This could be a contributing factor to the reduction in autophagy induced damage. Immunochemistry and western blot showed that mTOR expression in treated rats was marginally different 24 h after injury, and this could also be significant in the mechanism. Furthermore, terminal deoxynucleotidyl transferase- (TdT-) mediated dUTP nick end labeling (TUNEL) staining proved that the drugs are effective in reducing apoptosis. The upregulation of Beclin-1 and Mcl-1 and downregulation of Bcl-2, caspase-3, and the Bcl-2/Beclin-1 ratio infer that the neuroprotective effect of DAHP and TP act via the mediation of autophagy and apoptosis pathways.

Neuroprotective effects of DAHP and Triptolide in Focal Cerebral Ischemia via Apoptosis Inhibition and PI3K/Akt/mTOR pathway Activation

Triptolide (TP), one of the major active components of the traditional Chinese herb Tripterygium wilfordii Hook F, and 2, 4-diamino-6-hydroxypyrimidine (DAHP), an inhibitor of tetrahydrobiopterin (BH4) synthesis, have been reported to have potent anti-inflammatory and immunosuppressive properties. However, the protective effects of TP and DAHP on cerebral ischemia have not been reported yet. In this study, we investigated the neuroprotective effects of TP and DAHP in a middle cerebral artery occlusion (MCAO) rat model. Furthermore, we examined whether the neuroprotective effects of TP and DAHP were associated with the inhibition of apoptosis through suppressing BH4 and inducible NOS (iNOS) synthesis or the activation of the phosphoinositide-3-kinase/serine-threonine kinase Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway. Our results showed that pretreatments with TP (0.2 mg/kg) and DAHP (0.5 g/kg) significantly reduced ischemic lesion volume, water content, and neuronal cell death compared with the vehicle MCAO rats. In addition, compared with the MCAO group, TP, and DAHP pretreatment groups significantly reduced astrocyte numbers, caspase-3, cleaved caspase-3, and NF-κB up-regulation, while increased Bcl-2 expression. Moreover, protein expressions of PI3K, Akt, and mTOR increased, while extracellular signal-regulated protein kinases 1 and 2 (ERK1 and ERK2) phosphorylation decreased in both the TP-treated rats and DAHP-treated rats. These results demonstrate that TP and DAHP can decrease cell apoptosis in focal cerebral ischemia rat brains and that the mechanism may be related to the activation of the PI3K/Akt/mTOR pathway and inactivation of the ERK1/2 pathway. Thus our hypothesis was reached PI3K/Akt/mTOR and ERK1/2 pathways may provide distinct cellular targets for a new generation of therapeutic agents for the treatment of stroke, and TP and DAHP may be potential neuroprotective agents for cerebral ischemia/reperfusion injury.

Mifepristone: a potential clinical agent based on its anti-progesterone and anti-glucocorticoid properties.

Abstract Nowadays, unwanted pregnancy is a major globe tragedy for millions of women, associated with significant direct and indirect costs, no matter for individuals or society. The progesterone receptor antagonist steroid, mifepristone has been widely and effectively using throughout the world for medical abortion, but to a lesser extent for emergency contraception. In this review, we hope to explore the role of mifepristone as a contraceptive, particularly for emergency contraception. Studies of mifepristone have also been expanding to the fields of endometriosis and uterine fibroids. Furthermore, this initially considered reproductive medicine has been investigated in some psychotic diseases and various disorders of hypercortisolism, because of its glucocorticoid receptor antagonism. Mifepristone was approved suitable for patients with hyperglycemia secondary to Cushing’s syndrome by the United States Food and Drug Administration (FDA) in 2012. The aim of this article is to review published reports on the anti-progesterone and anti-glucocorticoid properties of mifepristone as a clinical agent. There is a new insight into systematically describing and evaluating the potential efficiency of mifepristone administrated in the field of endocrine and neuroendocrine, not only in obstetrics and gynecology.

C16 peptide shown to prevent leukocyte infiltration and alleviate detrimental inflammation in acute allergic encephalomyelitis model

Integrins are important adhesion receptors for leukocytes binding to endothelial cellular adhesion molecules. Previous studies have suggested that blocking relevant integrins might prevent leukocyte infiltration and suppress clinical and pathological features of neuroinflammatory disease. Experimental autoimmune encephalomyelitis (EAE), a rodent model of Multiple sclerosis (MS), is characterized by chronic inflammatory disorder of the central nervous system in which circulating leukocytes enter the brain and spinal cord leading to inflammation, myelin damage and subsequent paralysis. To prove this hypothesis and explore a promising application for MS treatment, the effects of C16, an ανβ3 integrin-binding peptide, were tested in vitro and in vivo by transendothelial assay, electron microscopy observation, multiple histological and immunohistochemical staining. The results showed C16 inhibited transendothelial migration of the C8166-CD4 lymphoblast cells, and alleviated extensive spinal cord and brain infiltration of leukocytes and macrophages in the EAE model. Furthermore, a significant amelioration of astrogliosis and a dramatic decrease in demyelination and axonal loss were observed in C16 treated animals. The attenuating inflammatory progression may improve the regional environment and trigger further neuroprotective effects on myelin and axons, all this suggests that C16 peptide may be a promising therapeutic agent for multiple sclerosis.

Anti-Inflammatory and Neuroprotective Effects of Triptolide via the NF-κB Signaling Pathway in a Rat MCAO Model.

Stroke is the leading cause of neurological disability in humans. Middle cerebral artery occlusion (MCAO) followed by reperfusion is widely accepted to mimic stroke in basic medical research. Triptolide is one of the major active components of the traditional Chinese herb Tripterygium wilfordii Hook F, and has been reported to have potent anti‐inflammatory and immunosuppressive properties. Since its preclinical effects on stroke were still unclear, we decided to study the effects of Triptolide on focal cerebral ischemia/reperfusion injury in this study. The results showed that Triptolide treatment significantly attenuates brain infarction volume, water content, neurological deficits, and neuronal cell death rate, which were increased in the MCAO model rats. Immunohistochemistry was used to analyze the expression of glial fibrillary acidic protein (GFAP), Cyclooxygenase‐2 (COX‐2), inducible nitric oxide (iNOS), and NF‐κB in the ischemic brains. The administration of Triptolide showed down‐regulation of the iNOS, COX‐2, GFAP, and NF‐κB expression in MCAO rats. It also increased the expression of bcl‐2, and suppressed levels of bax and caspase‐3 compared with the MCAO group. Our findings revealed that Triptolide exerts its neuroprotective effects against inflammation with the involvement of inhibition of NF‐κB activation. Anat Rec, 299:256–266, 2016.

Anti-neuroinflammatory and neurotrophic effects of combined therapy with annexin II and Reg-2 on injured spinal cord.

The present study was designed to investigate the neuroprotective effects of Ca2+-dependent phospholipid-binding protein annexin II and a secreted protein Reg-2 (regeneration gene protein 2) in spinal cord injury (SCI) model produced by contusion SCI at T9 using the weight drop method. The agents were delivered intrathecally with Alzet miniosmotic pumps. We found that annexin II and Reg-2 remarkably reduced neuronal death, attenuated tissue damage and alleviated detrimental inflammation in vivo; meanwhile, a significant increase in white matter sparing and myelination area was observed. The propriospinal axons and long-distance supraspinal pathways were protected by the treatments as revealed by retrograde tracing. Basso Beattie Bresnahan locomotor rating scores also revealed a measurable behavioral improvement. However, no evident behavioral improvements in locomotor performance were achieved by the combined treatment with annexin II and Reg-2, compared with the separate treatment with annexin II and Reg-2.

The neuroprotective effects of Reg-2 following spinal cord transection injury.

This study was designed to elucidate the potential neuroprotective effects of Reg‐2 (regeneration gene protein 2) in a rodent model of spinal cord transection injury at the ninth thoracic level. Reg‐2 at 100 and 500 μg, recombinant rat ciliary neurotrophic factor, or vehicle were delivered intrathecally using Alzet miniosmotic pumps. We found that Reg‐2 treatment significantly reduced neuronal death in the spinal cord. There was also an attenuation of inflammation at the injury site and an increase in white matter sparing and retained myelination. Retrograde tracing revealed that Reg‐2 protected axons of long descending pathways at 6 weeks post‐SCI, and the number of FluoroGold‐labeled neurons in spinal and supraspinal regions was also significantly increased. Immunofluorescent staining confirmed that the spared white matter contained neurofilament‐positive axons. Moreover, behavioral improvements were revealed by Basso Beattie Bresnahan locomotor rating scores and grid‐walk analysis. These results suggest that Reg‐2 might promote functional recovery by increasing axonal growth, inhibiting neuronal apoptosis, and attenuating spinal cord secondary injury after SCI. Anat Rec, 2010.

The Recent Updates of Therapeutic Approaches Against Aβ for the Treatment of Alzheimer's Disease

One of the main neuropathological lesions observed in brain autopsy of Alzheimers disease (AD) patients is the extracellular senile plaques mainly composed of amyloid‐beta (Aβ) peptide. Recently, treatment strategies have focused on modifying the formation, clearance, and accumulation of this potentially neurotoxic peptide. β‐ and γ‐secretase are responsible for the cleavage of amyloid precursor protein (APP) and the generation of Aβ peptide. Treatments targeting these two critical secretases may therefore reduce Aβ peptide levels and positive impact on AD. Vaccination is also an advanced approach against Aβ. This review focuses on recent advances of our understanding of this key peptide, with emphasis on Aβ peptide synthesis, accumulation and neurotoxicity, and current therapies including vaccination and two critical secretase inhibitors. MicroRNAs (miRNAs) are a class of conserved endogenous small noncoding RNAs, known to regulate the expression of complementary messenger RNAs, involved in AD development. We therefore address the relationship of miRNAs in the brain and Aβ generation, as a novel therapeutic approach to the treatment of AD while also providing new insights on the etiology of this neurological disorder. Anat Rec, 2011.