Formaldehyde exposure alters miRNA expression profiles in the olfactory bulb.

It has been reported that inhaling formaldehyde (FA) causes damage to the central nervous system. However, it is unclear whether FA can disturb the function of the olfactory bulb. Using a microarray, we found that FA inhalation altered the miRNA expression profile. Functional enrichment analysis of the predicted targets of the changed miRNA showed that the enrichment canonical pathways and networks associated with cancer and transcriptional regulation. FA exposure disrupts miRNA expression profiles within the olfactory bulb.

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.

17ß-estradiol protects human eyelid-derived adipose stem cells against cytotoxicity and increases transplanted cell survival in spinal cord injury.

Stem cell transplantation represents a promising strategy for the repair of spinal cord injury (SCI). However, the low survival rate of the grafted cells is a major obstacle hindering clinical success because of ongoing secondary injury processes, which includes excitotoxicity, inflammation and oxidative stress. Previous studies have shown that 17b-estradiol (E2) protects several cell types against cytotoxicity. Thus, we examined the effects of E2 on the viability of human eyelid adipose-derived stem cells (hEASCs) in vitro with hydrogen peroxide (H2O2)-induced cell model and in vivo within a rat SCI model. Our results showed that E2 protected hEASCs against H2O2-induced cell death in vitro, and enhanced the survival of grafted hEASCs in vivo by reducing apoptosis. Additionally, E2 also enhanced the secretion of growth factors by hEASCs, thereby making the local microenvironment more conducive for tissue regeneration. Overall, E2 administration enhanced the therapeutic efficacy of hEASCs transplantation and facilitated motor function recovery after SCI. Hence, E2 administration may be an intervention of choice for enhancing survival of transplanted hEASCs after SCI.

Systematic hypothesis for post-stroke depression caused inflammation and neurotransmission and resultant on possible treatments.

Post-stroke depression (PSD) is a prevalent complex psychiatric disorder that causes delay to functional recovery from rehabilitation and also increases cognitive impairment. The etiology of PSD remains controversial and appears to be physical and psycho-social in origin, alone or in combination. The causes of PSD as well as the mechanisms conferring beneficial antidepressant effects in the context of ischemic brain injury are still unknown. In addition, appropriate treatment strategies for therapy to prevent stroke-induced depression-like behavior remain to be developed. This paper, therefore, proposes two hypotheses for post-stroke depression: The inflammatory hypothesis, which is the increased production of proinflammatory cytokines resulting from brain ischemia in cerebral areas causing the pathogenesis of post-stroke depression and the glutamate hypothesis, where the excess glucocorticoids released from stress-induced over-activation of hypothalamus-pituitary-adrenal (HPA) lead to dysfunction of glutamatergic transmission. Neurotrophins, especially brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) both play various roles in the central nervous system (CNS), attenuate apoptosis in cultured neurons, stimulate neurogenesis and increase survival and protect neuronal tissues from cell death induced by ischemia or depression. We also touch upon recent treatment strategies including inhibition of pro-inflammatory cytokines, SSRI, neurotrophins and cell-based therapies. In the present review, we provide an overview of recent evidence concerning the mechanisms of post-stroke depression and propose four prospective treatment strategies so as to provide references for clinical evidence-based medications.

[Research progress of external tufted cells in olfactory glomerulus].

External tufted (ET) cells are the major excitatory elements coordinating the activities of glomerulars and mediating the input from the olfactory neurons to mitral cells. The ET cells participate in inter-and intra-glomerular microcircuits in the olfactory bulb, link the isofunctional odor columns within the same olfactory bulb, and play an important role in olfactory information processing. This paper reviews the research progress of the anatomy and physiological properties and electrophysiological modeling of ET cells, elaborate the problems and defects in the field. And then it further gives some proposals for the future research of electrophysiological properties, development of olfactory information coding and performance of modeling of ET cells.

[GAD67-GFP expression and co-localization with bNOS in main olfactory bulb of GAD67-GFP knock-in mouse].

OBJECTIVE: To investigate the distribution of GAD67 and the co-localization with bNOS in the main olfactory bulb of GAD67-GFP knock-in mouse. METHODS: Polymerase chain reaction was applied to identify the genotype of GAD67-GFP knock-in mouse, the animals were sacrificed and frozen sections of olfactory bulb were prepared. The Nissl-staining was performed to show an framework of the neuron in the olfactory bulb. The distribution of GAD67 and co-localization with bNOS were detected by immunofluorescence technique. RESULTS: The proportion of GAD67-positive cells among DAPI-positive cells were (42.98 ± 0.92)% in glomerular layer, (23.64 ± 0.84)% in mitral cell layer and (77.75 ± 0.84)% in granule cell layer; the bNOS-positive cells mainly existed in glomerular layer and mitral cell layer, very few in granule cell layer. No co-localization of GAD67 and bNOS in granule cell layer and mitral cell layer was found, but there was dispersed distribution in glomerular layer. CONCLUSION: GAD67-positive neurons mainly appear in glomerular layer and granule cell layer, and the bNOS is mostly expressed in glomerular layer and mitral cell layer; while the co-localization of GAD67 and bNOS only occurs in glomerular layer of olfactory bulb.

Decreased purinergic inhibition of synaptic activity in a mouse model of Niemann-Pick disease type C.

Niemann-Pick disease type C (NPC) is a progressive neurodegenerative disorder characterized by accumulation of free cholesterol in lysosomes, mainly due to a mutation in the NPC1 gene. The pathophysiological basis of the neural disorders in NPC, however, is not well understood. We found that the hippocampal field excitatory postsynaptic potential (fEPSP) was enhanced in NPC1 mutant mice. A1-receptor antagonist or adenosine degrading enzyme enhanced the fEPSP in both types of mice, but had a much weaker effect in the mutant mice, suggesting less tonic inhibition of synaptic transmission by endogenous adenosine in the mutant. Further evidence showed impaired hippocampal long term potentiation (LTP) in mutant mice. Supplement of A1 agonist N6-Cyclopentyladenosine (CPA) partially rescued the impaired LTP in mutant mice. Moreover, adenosine release from hippocampal slices was significantly decreased in the mutant. The enhanced excitatory synaptic transmission and the decreased synaptic plasticity due to the decreased adenosine release in NPC brain may partially contribute to the neural disorders of NPC disease, such as seizures, neurodegeneration, and dementia.

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 Ca(2+)-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 T(9) 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.

Expression changes of transforming growth factor-beta1 and thrombospondin-1 in cavernous tissues of diabetic rats.

OBJECTIVE: To assess transforming growth factor-beta1 (TGF-beta1) and thrombospondin-1 (TSP-1) expression in the cavernous tissue of rats with streptozotocin (STZ)-induced diabetes. MATERIALS AND METHODS: Twenty male Sprague-Dawley rats were randomly divided into 2 groups: diabetics and controls. We injected STZ intraperitoneally to induce diabetes, and studied the alterations in TGF-beta1 and TSP-1 expression in the cavernous tissue of the 2 groups by immunohistochemistry and real-time quantitative reverse transcription polymerase chain reaction. HE staining was also applied to determine morphological changes. Weight, blood sugar and urine sugar were measured before and after model induction in both groups. RESULTS: Expression of TGF-beta1 and TSP-1 increased significantly in the cavernous tissue of the diabetic rats compared to the control group. CONCLUSIONS: TGF-beta1 and TSP-1 expression changes in cavernous tissues may play an important role in diabetic erectile dysfunction.

[Formaldehyde inhalation may damage olfactory bulb and hippocampus in rats].

OBJECTIVE: To investigate the effects of formaldehyde inhalation on the morphological damage, and Glu, GABA and NOS contents in olfactory bulb and hippocampus of rats. METHODS: Twenty SD rats were equally divided into two groups: rats in the control group inhaled fresh air, while the animals in experimental group were exposed to the air containing formaldehyde (12.5 mg/m(3), 4 h/d) for 7 days. Then rats were sacrificed and frozen sections of olfactory bulb and hippocampus were prepared. The morphological changes were examined and the Glu, GABA and NOS contents were detected using Nissl-staining, immunohistochemistry and Western blot, respectively. RESULT: Compared with the control group, there was a significant confusion and shrink of neuron morphology in experimental group, the number and staining intensity of Glu and NOS positive cells and protein contents were reduced. The protein expression of GABA was also decreased in the formaldehyde group. CONCLUSION: Formaldehyde inhalation can cause a severe morphological damage of olfactory bulb and hippocampus in SD rats,which may further impair memory and learning ability through the reduction of Glu, GABA and NOS expression.

Nestin positive cells in the retina and spinal cord of the sturgeon after hypoxia.

Sturgeon is an archaic fish which first evolved 100-200 million years ago and has changed very little morphologically since then. In the current study, we are interested in the effects of hypoxia on the retina and spinal cord of this archaic fish. Immunohistochemistry was used to detect the expression pattern of nestin, an intermediate neurofilament, after 10 min and 30 min of hypoxia. Our results showed that nestin-expression in these two neural regions are very different. In the normal retina, nestin was widely distributed throughout the retina while it was absent in the normal spinal cord. However, once the sturgeon was exposed to hypoxic condition, even one of short duration, the pattern of nestin expression was reversed and it is now absent in the hypoxic retina but is present in the hypoxic spinal cord. These results suggest that nestin expression, which is usually associated with glial reactivation, may be further influenced by other undetermined factors in this archaic fish.

Olfactory deficit is associated with mitral cell dysfunction in the olfactory bulb of P301S tau transgenic mice.

Neurofibrillary tangles consisting of hyperphosphorylated tau (P-tau) are the neuropathological hallmark of Alzheimer's disease (AD), and olfaction disorder is an early symptom of AD. However, the link between P-tau aggregation and olfaction disorder remains unclear. In this study, the expression of P-tau in the olfactory bulb (OB), particularly in the mitral cell layer (MCL), external plexiform layer (EPL), and granule cell layer (GCL), of AD patients was found to be significantly higher than that in the OB of normal aging subjects, which suggested that these layers in the OB were susceptible to P-tau. The P301S tau transgenic mice (P301S mice) exhibit AD-like features, which can be characterized by olfactory dysfunction that precedes cognitive disorder. Importantly, the excessive P-tau expression in the OB of P301S mice, particularly in MCs, was associated with MC loss at 9 months of age, and decreased MC firing activities started to be observed at 2 months of age. Our results revealed that MCs might contribute to olfactory dysfunction in P301S mice. Furthermore, we described an aberrant dendro-dendritic synaptic structure between granule cells (GCs) and MCs and abnormal gamma oscillations in the EPL of the OB, and these findings indicated that P-tau might disrupt the regulation of MCs by GCs in P301S mice starting at 5 months of age. These data showed that the reduction in the MC firing frequency at 2 months of age might not be caused by GC suppression. Based on these findings, we speculated that MCs are a putative target for the treatment of P-tau-induced early olfactory dysfunction, and thus, an exploration of the specific causes and mechanisms of MC functional changes in P301S mice is crucial.

Impairment of Dendrodendritic Inhibition in the Olfactory Bulb of APP/PS1 Mice.

Olfactory dysfunction is an early event in Alzheimer's disease (AD). However, the mechanism underlying the AD-related changes in the olfactory bulb (OB) remains unknown. Granule cells (GCs) in the OB regulate the activity of mitral cells (MCs) through reciprocal dendrodendritic synapses, which is crucial for olfactory signal processing and odor discrimination. Nevertheless, the relationships between the morphological and functional changes of dendrodendritic synapses, particularly the local field potentials (LFPs) as a consequence of olfactory disorders in patients with AD have not been investigated. Here, we studied the morphological and functional changes induced by dendrodendritic inhibition in GCs onto MCs in the OB of amyloid precursor protein (APP)/PS1 mice and age-matched control mice during aging, particular, we focused on the effects of olfactory disorder in the dendrodendritic synaptic structures and the LFPs. We found that olfactory disorder was associated with increased amyloid-ß (Aß) deposits in the OB of APP/PS1 mice, and those mice also exhibited abnormal changes in the morphology of GCs and MCs, a decreased density of GC dendritic spines and impairments in the synaptic interface of dendrodendritic synapses between GCs and MCs. In addition, the aberrant enhancements in the γ oscillations and firing rates of MCs in the OB of APP/PS1 mice were recorded by multi-electrode arrays (MEAs). The local application of a GABAAR agonist nearly abolished the aberrant increase in γ oscillations in the external plexiform layer (EPL) at advanced stages of AD, whereas a GABAAR antagonist aggravated the γ oscillations. Based on our findings, we concluded that the altered morphologies of the synaptic structures of GCs, the dysfunction of reciprocal dendrodendritic synapses between MCs and GCs, and the abnormal γ oscillations in the EPL might contribute to olfactory dysfunction in AD.

The expression and the functional roles of tissue factor and protease-activated receptor-2 on SW620 cells.

Tissue factor (TF) is believed to play an important role in tissue repair, inflammation, angiogenesis, and tumor metastasis. Protease-activated receptors (PARs) are widely expressed on various cells including tumor cells and associated with many pathological mechanisms. In the present study, the expression of TF and PAR1, PAR2 on human colon cancer cells (SW620 and SW480) was investigated and their functional roles on the behavior of tumor cells were evaluated. It was demonstrated that SW620 and SW480 cells expressed TF at antigen, activity and mRNA levels. However, the highly metastatic cell line SW620 showed slightly higher TF expression than the low metastatic cell line SW480. The PAR2 antigen was strongly expressed on the membrane of SW620 cells, but not on SW480 cells. The PAR1 antigen was not observed in SW620 or SW480 cells, while PAR1 and PAR2 mRNA was detected in SW620 and SW480 cells. The migratory potential of SW620 was stronger than that of SW480 seen in Boyden chambers. PAR2 agonist (SLIGKV-NH2) and factor VIIa significantly stimulated SW620 cell proliferation, migratory activity, and interleukin 8 (IL-8) secretion compared to control. The stimulating effects of factor VIIa could be inhibited by anti-TF and anti-PAR2 but not anti-PAR1 antibodies. In summary, this study demonstrates that TF and PAR2 are strongly expressed on highly metastatic colonic tumor cells and are closely associated with the proliferation and migration of the cells. TF may elucidate its roles in colonic cancer invasion and metastasis via PAR2 pathway.

[Cortical neuron apoptosis induced by beta-amyloid peptide and protective effect of panoxadiol in mice].

OBJECTIVE: To investigate the apoptosis of cortical neurons induced by beta-amyloid peptide (Abeta(1-40)) and the protective effect of panoxadiol. METHODS: The Abeta(1-40) induced damage of primarily cultured mouse cortical neurons was examined with morphological observation, MTT assay, DNA agarose gel electrophoresis and Western-blot. RESULT: After 48 h treated with 12 mumol/L Abeta(1-40), the cortical neurons showed apoptotic characteristics: including decreased OD570 value in MTT assay, DNA cleavage fragment in electrophoresis and increased apoptotic cells. Western-blot showed that the expression of bcl-2 reduced significantly (P<0.05). Cell apoptosis was significantly attenuated in 40 mg/L panoxadiol treated group. CONCLUSION: Panoxadiol can protect cultured cortical neurons from apoptosis induced by Abeta(1-40) in mice.

[Expression of RAG-1 in brain during mouse development].

OBJECTIVE: To investigate the expression of recombination activating gene-1 (RAG-1) and its localization in the mouse brain during the embryonic development. METHODS: The brain tissues of E (embryonic day) 11, E13, E15, E17, E19, P0 (the birth day) and adult mice were taken, the total RNA of brains were extracted and the changes of RAG-1 expression were detected with the method of RT-PCR. The freeze sections of brain tissues from each group were stained with immunohistochemistry method. RESULT: The expression of RAG-1 persisted from E11 to P0 brain and was steadily increased from E11 to E19; the results of RT-PCR were similar to that of immunohistochemistry. The positive-cells mainly appeared in the nucleus amygdalae, hypothalamus, thalamus and hippocampus at developmental stage. The expression began to appear in ventricular zone (VZ) and intermediate zone (IZ) of telecephalic vesicle, then gradually increased in subventricular zone (SVZ), corticle plate (CP) and subcorticle plate (SP). CONCLUSION: The expression of RAG-1 in mouse embryonic brain tissue is higher than that in the adult mouse, which may be related to the process of neuron development.

[Substance P and/or calcitonin gene-related peptide immunoreactive neurons in dorsal root ganglia possibly involved in the transmission of nociception in rat penile frenulum].

OBJECTIVE: To study the relationship between substance P (SP) and/or calcitonin gene-related peptide (CGRP) immunoreactive neurons in dorsal root ganglia (DRG) and the transmission of nociception in the penile frenulum of rats. METHODS: The fluoro-gold (FG) retrograde tracing method was used to trace the origin of nerve terminals in the penile frenulum of rats. And SP and/or CGRP immunofluorescence labeling was employed to detect the distribution of SP and/or CGRP immunoreactive neurons in DRG. RESULTS: FG retrograde tracing showed that the FG retrolabeled neurons were localized in L6-DRG and S1-DRG. SP and/or CGRP immunofluorescence labeling indicated that a large number of DRG neurons were SP- and CGRP-immunoreactive, different in size, bright red and bright green respectively in color, and arranged in rows or spots among nerve bundles. All the FG/SP and FG/CGRP double-labeled neurons were medium or small-sized. One third of the FG-labeled neurons were SP-immunoreactive, and a half of them CGRP-immunoreactive in L6-DRG and S1-DRG respectively. The FG/SP/CGRP-labeled neurons accounted for one fifth of the FG retro labeled neurons. CONCLUSION: SP- and CGRP-immunoreactive neurons in L6-DRG and SI-DRG of rats may be involved in the transmission of nociception in rat penile frenulum.

MiR-124 Promotes Newborn Olfactory Bulb Neuron Dendritic Morphogenesis and Spine Density.

Using microarray analysis, we detected microRNA-124 (miR-124) to be abundantly expressed in the olfactory bulb (OB). miR-124 regulates adult neurogenesis in the subventricular zone (SVZ). However, much less is known about its role in newborn OB neurons. Here, using both gain-of-function and loss-of-function approaches, we demonstrate that brain-specific miR-124 affects dendritic morphogenesis and spine density in newborn OB neurons. Functional Annotation Clustering of miR-124 targets was enriched in "cell morphogenesis involved in neuron differentiation."

miR-30c and semaphorin 3A determine adult neurogenesis by regulating proliferation and differentiation of stem cells in the subventricular zones of mouse.

OBJECTIVES: Mechanisms that regulate proliferation of adult neural stem cells are largely unknown. Here, we have investigated the role of microR-30c (miR-30c) and its target, semaphoring 3A (sema3A), in regulating adult neurogenesis and mechanisms underlying this process. MATERIALS AND METHODS: In situ hybridization, immunofluorescence and quantitative real-time PCR were used to assess complementary expression patterns of miR-30c and sema3A in mice. Effects of miR-30c in the subventricular zone (SVZ) were examined by stereotaxic injection of up- and down-regulating lentiviruses. 5'-bromo-2'-deoxyuridine labelling was performed to investigate effects of miR-30c and sema3A on adult neurogenesis. Real-time cell assays, morphological analysis and cell cycle measurements were used to reveal the mechanisms by which miR-30c and sema3A regulate adult neurogenesis. RESULTS: Expression of miR-30c negatively correlated with that of sema3A in neurons, and levels of miR-30c and sema3A correlated positively with numbers of newborn cells in the SVZ and rostral migration stream. miR-30c and sema3A affected adult neurogenesis by regulating proliferation and differentiation, as well as cycles of stem cells in the SVZ. CONCLUSIONS: miR-30c and sema3A regulate adult neurogenesis by controlling proliferation and differentiation of stem cells in the SVZ. This finding reveals a novel regulatory mechanism of adult neurogenesis.

microRNA Profiling of Amniotic Fluid: Evidence of Synergy of microRNAs in Fetal Development.

Amniotic fluid (AF) continuously exchanges molecules with the fetus, playing critical roles in fetal development especially via its complex components. Among these components, microRNAs are thought to be transferred between cells loaded in microvesicles. However, the functions of AF microRNAs remain unknown. To date, few studies have examined microRNAs in amniotic fluid. In this study, we employed miRCURY Locked Nucleotide Acid arrays to profile the dynamic expression of microRNAs in AF from mice on embryonic days E13, E15, and E17. At these times, 233 microRNAs were differentially expressed (p< 0.01), accounting for 23% of the total Mus musculus microRNAs. These differentially-expressed microRNAs were divided into two distinct groups based on their expression patterns. Gene ontology analysis showed that the intersectional target genes of these differentially-expressed microRNAs were mainly distributed in synapse, synaptosome, cell projection, and cytoskeleton. Pathway analysis revealed that the target genes of the two groups of microRNAs were synergistically enriched in axon guidance, focal adhesion, and MAPK signaling pathways. MicroRNA-mRNA network analysis and gene- mapping showed that these microRNAs synergistically regulated cell motility, cell proliferation and differentiation, and especially the axon guidance process. Cancer pathways associated with growth and proliferation were also enriched in AF. Taken together, the results of this study are the first to show the functions of microRNAs in AF during fetal development, providing novel insights into interpreting the roles of AF microRNAs in fetal development.