Henry Davies

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.

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.

Dose-Dependent Anti-Inflammatory and Neuroprotective Effects of an ανβ3 Integrin-Binding Peptide

Previous studies have shown that prevention of leukocyte infiltration by targeting integrins involved in transendothelial migration may suppress the clinical and pathological features of neuroinflammatory disease. This study was designed to investigate the effects of C16, an α ν β3 integrin-binding peptide, in an acute experimental allergic encephalomyelitis (EAE) rat model. Multiple histological and immunohistochemical staining, electron microscopy observation, ELISA assay, Western blot, and magnetic resonance imaging (MRI) were employed to assess the degree of inflammation, axonal loss, neuronal apoptosis, white matter demyelination, and extent of gliosis in the brain and spinal cord of differently treated EAE models. The results showed that C16 treatment could inhibit extensive leukocyte and macrophage accumulation and infiltration and reduce cytokine tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) expression levels. A significantly lower clinical score at the peak time of disease was also demonstrated in the C16 treated group. Moreover, astrogliosis, demyelination, neuronal death, and axonal loss were all alleviated in C16 treated EAE animals, which may be attributed to the improvement of microenvironment. The data suggests that C16 peptide may act as a protective agent by attenuating inflammatory progression and thus affecting the expression of some proinflammatory cytokines during neuroinflammatory disease.

Contribution of Rag1 to spatial memory ability in rats

Rag1 plays a critical role in the development and maturation of lymphocytes, and is related to immune memory functions. Deletion of Rag1 results in a lack of mature functional B and T lymphocytes. Rag1 transcription is most apparent in regions of the postnatal brain with high neuronal cell density--the cerebellum and the hippocampal formation, both of which are relevant to learning and memory function. In this research, three pairs of shRNA targeting Rag1 and a pair of scrambled sequences were constructed, packaged within a lentiviral vector system, and transferred into the cultured rat hippocampal neuron cells in vitro. Meanwhile, the lentivirus was injected stereotaxically into CA3 of the rat hippocampus, where the positive immunofluorescence for GFP expression was located. Rag1 mRNA expression was detected by RT-PCR 7, 14 and 28 days after stereotaxic injection. Assessment in the Morris water maze test 28 days post stereotaxic injection showed a loss of spatial learning and memory in the experimental rats. In long-term potentiation research, the experimental group did not display remarkable disparity in comparison with the control group. These findings indicate that the knockdown of Rag1 expression in the hippocampus may impair spatial learning and memory ability in rats.

miR-16 and Fluoxetine Both Reverse Autophagic and Apoptotic Change in Chronic Unpredictable Mild Stress Model Rats

In the clinic selective serotonin reuptake inhibitors (SSRIs), like Fluoxetine, remain the primary treatment for major depression. It has been suggested that miR-16 regulates serotonin transporters (SERT) via raphe nuclei and hippocampal responses to antidepressants. However, the underlying mechanism and regulatory pathways are still obtuse. Here, a chronic unpredicted mild stress (CUMS) depression model in rats was established, and then raphe nuclei miR-16 and intragastric Fluoxetine injections were administered for a duration of 3 weeks. An open field test and sucrose preference quantification displayed a significant decrease in the CUMS groups when compare to the control groups, however these changes were attenuated by both miR-16 and Fluoxetine treatments. A dual-luciferase reporter assay system verified that hsa-miR-16 inhibitory effects involve the targeting of 3′UTR on the 5-HTT gene. Expression levels of miR-16 and BDNF in the hippocampus were examined with RT-PCR, and it was found that increased 5-HT2a receptor expression induced by CUMS can be decreased by miR-16 and Fluoxetine administration. Immunofluorescence showed that expression levels of neuron NeuN and MAP-2 in CUMS rats were lower. Apoptosis and autophagy levels were evaluated separately through relative expression of Bcl-2, Caspase-3, Beclin-1, and LC3II. Furthermore, CUMS was found to decrease levels of hippocampal mTOR, PI3K, and AKT. These findings indicate that apoptosis and autophagy related pathways could be involved in the effectiveness of antidepressants, in which miR-16 participates in the regulation of, and is likely to help integrate rapid therapeutic strategies to alleviate depression clinically. These findings indicate that miR-16 participates in the regulation of apoptosis and autophagy and could account for some part of the therapeutic effect of SSRIs. This discovery has the potential to further the understanding of SSRIs and accelerate the development of new treatments for depression.

The alteration of 5-HT2A and 5-HT2C receptors is involved in neuronal apoptosis of goldfish cerebellum following traumatic experience

5-HT receptor changes remain controversial in posttraumatic stress disorder (PTSD) models. This study looks at the relationship between traumatic injuries and the alterations in 5-HT(2A) and 5-HT(2C) receptors in the goldfish brain. The effect of treatment with doxepin and fluoxetine, known to be selective serotonin reuptake inhibitor (SSRI) antidepressants, on 5-HT receptor expression in goldfish with fin ablation was also investigated. We demonstrated that fin ablation induced anxiety-like behavioural alterations and significant up-regulation of c-fos expression in goldfish cerebellum. The behavioural alterations correlated well with an increased expression of 5-HT(2A) receptors in the cerebellum of the fish with traumatic injury. An increase in the number of apoptotic cells and a higher caspase-8 protein level was present in the brains of goldfish with fin ablation compared to the control. Our findings suggest that neuronal apoptosis occured in the cerebellum as a result of fin ablation and may be related to the alterations of 5-HT(2A) and 5-HT(2C) levels and that the beneficial clinical effects of doxepin/fluoxetine treatment are due to the down-regulation of 5-HT(2A) and up-regulation of 5-HT(2C) receptors in the brain.

Improved Neural Regeneration with Olfactory Ensheathing Cell Inoculated PLGA Scaffolds in Spinal Cord Injury Adult Rats.

Background/Aims: Every year, around the world, between 250000 and 500000 people suffer from spinal cord injury (SCI). This study investigated the potential for poly (lactic-co-glycolic acid) (PLGA) complex inoculated with olfactory ensheathing cells (OECs) to treat spinal cord injury in a rat model. Methods: OECs were identified by immunofluorescence based on the nerve growth factor receptor (NGFR) p75. The Basso, Beattie, and Bresnahan (BBB) score, together with an inclined plane (IP) test were used to detect functional recovery. Nissl staining along with the luxol fast blue (LFB) staining were independently employed to illustrate morphological alterations. More so, immunofluorescence labeling of the glial fibrillary acidic protein (GFAP) and the microtubule-associated protein-2 (MAP-2), representing astrocytes and neurons respectively, were investigated at time points of weeks 2 and 8 post-operation. Results: The findings showed enhanced locomotor recovery, axon myelination and better protected neurons post SCI when compared with either PLGA or untreated groups (P < 0.05). Conclusion: PLGA complexes inoculated with OECs improve locomotor functional recovery in transected spinal cord injured rat models, which is most likely due to the fact it is conducive to a relatively benevolent microenvironment, has nerve protective effects, as well as the ability to enhance remyelination, via a promotion of cell differentiation and inhibition of astrocyte formation.

Altered Morphologies and Functions of the Olfactory Bulb and Hippocampus Induced by miR-30c.

Adult neurogenesis is considered to contribute to a certain degree of plasticity for the brain. However, the effects of adult-born neurons on the brain are still largely unknown. Here, we specifically altered the expression of miR-30c in the subventricular zone (SVZ) and dentate gyrus (DG) by stereotaxic injection with their respective up- and down-regulated lentiviruses. Results showed an increased level of miR-30c enhanced adult neurogenesis by prompting cell-cycles of stem cells, whereas down-regulated miR-30c led to the opposite results. When these effects of miR-30c lasted for 3 months, we detected significant morphological changes in the olfactory bulb (OB) and lineage alteration in the hippocampus. Tests of olfactory sensitivity and associative and spatial memory showed that a certain amount of adult-born neurons are essential for the normal functions of the OB and hippocampus, but there also exist redundant newborn neurons that do not further improve the functioning of these areas. Our study revealed the interactions between miRNA, adult neurogenesis, brain morphology and function, and this provides a novel insight into understanding the role of newborn neurons in the adult brain.

Prospective Role of MicroRNAs in Depression

BACKGROUND Depression is a debilitating disease that is affecting a growing number of patients, both physically and mentally. In addition to mood changes, depression results in cognitive impairment. Although depression studies have been going on for decades, the underlying mechanism still remains unclear. MicroRNAs (miRNAs), a type of small non-coding RNAs, predominantly control the expression of their target mRNAs to exert their functions. Some evidences have revealed the importance of miRNAs in the mechanism of depression,however, these studies are still in their infancy. Alterations in brain regions, synaptic plasticity, hypothalamic-pituitary-adrenal (HPA) axis, changes in the levels of serotonin and glucocorticoids, together with stress response have been proven to be involved in depression. These alterations can influence cognition, learning and memory, with recent evidences demonstrating the involvement of miRNAs in several aspects of stress response, neural plasticity and neurogenesis as well as pathogenesis of depression. OBJECTIVE In light of these theories of depression, this review was aimed at elucidating the role of miRNAs in the underlying mechanisms of depression resulting in cognitive, learning and memory impairments. METHOD/RESULTS Both PubMed and Scopus databases were employed in scouring for research reports pertaining to this area of study. A total of 180 articles were obtained from these two databases. CONCLUSION With the probing of classical theories of depression as well as the connection between miRNAs and depression, more studies,nevertheless, are needed to ascertain the full mechanism of depression along with its resultant cognitive, learning and memory impediments.