Ya-Lin Huang

Fudan University, Shanghai, Shanghai Shi, China

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Publications (10)30.04 Total impact

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    ABSTRACT: Our previous experiments suggest that treatment with Bcl-2 increases proliferation and differentiation of neuronal progenitors induced by ischemic injury and ameliorates neurological functional deficits after stroke. However, in addition to its traditional anti-apoptotic effect, little is known about the concrete molecular modulation mechanism. In this study, Bcl-2-expressing plasmids were injected into the lateral ventricle of rat brains immediately following a 30-min occlusion of the middle cerebral artery to determine the role of Bcl-2 in adult neurogenesis. Bcl-2 overexpression reduced ischemic infarct and astrogenesis, and enhanced ischemia-induced striatal neurogenesis. We further found that Bcl-2 increased β-catenin, a key mediator of canonical Wnt/β-catenin signaling pathway, and reduced bone morphogenetic proteins-4 (BMP-4) expression in the ipsilateral striatum following ischemia. Treatment of stroke with β-catenin siRNA (i.c.v.) showed that β-catenin siRNA antagonized Bcl-2 neuroprotection against ischemic brain injury. More interestingly, β-catenin siRNA simultaneously abolished Bcl-2-mediated reduction of BMP-4 expression and enhancement of neurogenesis in the ipsilateral striatum. This effect is independent of Noggin, the known BMP antagonist. These findings highlight a new regulatory mechanism that Bcl-2 elevates ischemia-induced striatal neurogenesis by down-regulating expression of BMP-4 via activation of the Wnt/β-catenin signaling pathway in adult rat brains.
    Neurochemistry International 04/2012; 61(1):34-42. · 2.66 Impact Factor
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    ABSTRACT: Vascular endothelial growth factor (VEGF) protects neurons against ischemic injury. An overload of intracellular calcium ions (Ca(2+)) caused by the excessive release of glutamate is widely considered to be one of the molecular mechanisms of ischemic neuronal death. In the present study, we investigated whether VEGF could modulate the activity of Ca(2+) channels on the neuronal membrane. We used the Fluo-3 image method assisted by confocal laser scan microscopy to detect any Ca(2+) influx in primary cultured hippocampal neurons. Whole-cell patch-clamp techniques were used to record the activity of the high-voltage-activated (HVA) Ca(2+) currents in the CA1 pyramidal neurons of hippocampal slices that were freshly prepared from neonatal brains of rats. The results obtained from the Fluo-3 image experiments showed that VEGF pretreatment of cultured neurons at a final concentration of 50, 100, or 200 ng/ml acutely and dose dependently attenuated the Ca(2+) influx induced by application of KCl (60 mM) or glutamate (50 microM). This effect was blocked by SU1498, an antagonist of Flk-1 VEGF receptor. The influx of Ca(2+) returned to basal levels after removal of VEGF. Furthermore, electrophysiological recording data showed that VEGF could acutely reduce the amplitudes of the HVA Ca(2+) currents in a dose- and voltage-dependent manner. The HVA Ca(2+) currents also returned to the levels of the control after removal of VEGF from the system. Taken together, the results obtained from the present study demonstrated that VEGF specifically reduced the influx of Ca(2+) via the inhibitory activity of the HVA Ca(2+) channels in hippocampal neurons.
    Journal of Neuroscience Research 10/2008; 87(2):393-402. · 2.97 Impact Factor
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    ABSTRACT: In this study, we tested if caspase-3 inhibition decreased ischemia-induced Abeta elevation by reducing beta-secretase (BACE1) activity. Changes in caspase-3, Abeta and BACE1 levels were detected in rat striatum on different days after middle cerebral artery occlusion using immunostaining. We found that the positive labeled cells of activated caspase-3, Abeta, and BACE1 were significantly and time-dependently increased in the ipsilateral striatum. The results of Western blotting and RT-PCR showed that caspase-3 inhibitor Z-DEVD-FMK reduced BACE1 mRNA and protein levels, and inhibited its protease activity, thereby decreasing the amount of APP C99 and Abeta in ischemic brains. Moreover, Z-DEVD-FMK reduced BACE1 and GFAP double-labeled cells, but not GFAP protein levels or GFAP-labeled cells, in the ipsilateral striatum. Thus, we demonstrated that caspase-3 inhibition attenuated ischemia-induced Abeta formation by reducing BACE1 production and activity. This finding provides a therapeutic strategy for preventing Abeta accumulation and reducing the risk of neurodegeneration after stroke.
    Neurobiology of Disease 10/2008; 32(3):433-41. · 5.62 Impact Factor
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    Ming He, Ya-Lin Huang, Lin Zhang, Tai Yao, Li-Min Lu
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    ABSTRACT: The renin/prorenin receptor (RnR) has recently been cloned and demonstrated to exist in different cells in the cardiovascular and renal systems, playing an important role in physiological and pathophysiological situations. In the present study, we used immunofluorescence method to identify whether and where the RnR expressed in cultured rat renal mesangial cells (MCs) and rat kidney. By using the prorenin handle region peptide (HRP) as a decoy peptide of the RnR, we observed the distribution of the HRP-RnR complex in the MCs. Our results showed that the RnR was localized in the perinuclear zone and plasma membrane of the MCs. At the organ level, the RnR was observed in the mesangium of cortical glomeruli in rat kidney. The FITC-labeled HRP (FITC-HRP) translocated from cell culture medium into the cytoplasm within 30 s. Colocalization of the HRP and RnR was observed mainly on the cell membrane and in the perinuclear zone of cytoplasm by using immunofluorescence and confocal microscopy. At 30 min the FITC-HRP was mainly observed in the nucleus while the RnR remained in the perinuclear zone of cytoplasm. Taken together, our results confirm the expression of RnR in the renal MCs. It is suggested that internalization of the RnR after binding with its ligand is at least one of the pathways through which the RnR exerts its biological actions.
    Sheng li xue bao: [Acta physiologica Sinica] 01/2008; 59(6):796-804.
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    ABSTRACT: To determine whether Bcl-2 could influence adult neurogenesis and prevent apoptosis of newborn neurons, we injected Bcl-2 expressing plasmid into the lateral ventricle of rat brain immediately following a 30-min occlusion of the middle cerebral artery (MCAO). We found that Bcl-2 increased neural progenitor cells (BrdU+-DCX+) in the ipsilateral striatum, newborn immature neurons (BrdU+-Tuj-1+) and newborn mature neurons (BrdU+-MAP-2+) in the ipsilateral striatum and frontal cortex at 1 to 4 weeks following MCAO. Bcl-2 overexpression promoted development of newborn neurons into GABAergic and cholinergic neurons in the ipsilateral striatum. Moreover, Bcl-2 significantly decreased the apoptosis of newborn neurons, determined by double staining of Tuj-1 and activated caspase-3 (Tuj-1+-Casp+). These results indicate that overexpression of Bcl-2 in adult rat brain enhances neurogenesis and survival of newborn neurons. Increasing neurogenesis and preventing the death of newborn neuron may be a strategy to aid in the repair of adult brain after stroke.
    Neurobiology of Disease 12/2006; 24(2):345-56. · 5.62 Impact Factor
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    ABSTRACT: Increasing lines of evidence indicate that estrogen acts as a neuroprotective agent through a nongenomic mechanism. We tested the hypothesis that 17beta-estradiol could rapidly attenuate glutamate-induced calcium (Ca2+) overload in rat primary hippocampal neurons via a membrane receptor-dependent mechanism. The bulk cytosolic intracellular Ca2+ level was measured in neurons with fluorescent Ca2+ probe fluo3. Preexposure of primary cultured hippocampal neurons to 17beta-estradiol for 3 min attenuated intracellular Ca2+ increase induced by glutamate in a concentration-dependent manner. The action of 17beta-estradiol was reversible after washout. Administration of membrane-impermeable 17beta-estradiol conjugated to bovine serum albumin (E2-BSA) produced the same effect, suggesting possible involvement of cell membrane receptors. ICI 182,780, a specific estrogen receptor (ER) antagonist, blocked the neuronal response to 17beta-estradiol and estradiol BSA, indicating a role of specific ERs. The present study demonstrates that 17beta-estradiol acutely reduces glutamate-stimulated intracellular Ca2+ increase via ERs probably on the cell surface of the hippocampal neurons.
    Brain Research 12/2004; 1026(2):254-60. · 2.88 Impact Factor
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    ABSTRACT: The antisense knockdown technique and confocal laser scanning microscopic analysis were used to elucidate vascular endothelial growth factor (VEGF) induction and its effect on DNA damage and repair in rat brain following a transient middle cerebral artery occlusion. Immunohistochemical study and in situ hybridization showed that the expression of VEGF and its mRNA was enhanced in the ischemic core and penumbra of ischemic brain. Western blot analysis further illustrated that VEGF induction was time-dependently changed in these areas. Double-staining analysis indicated that VEGF-positive staining existed in the neuron, but not in the glia, and it colocalized with excision repair cross-complementing group 6 (ERCC6) mRNA, a DNA repair factor. VEGF antisense oligodeoxynucleotide infusion reduced VEGF induction and resulted in an enlargement of infarct volume of the brain caused by ischemia. Moreover, it also increased the number of DNA damaged cells and lessened the induction of ERCC6 mRNA in ischemic brains. These results suggest that the induction of endogenous VEGF in ischemic neurons plays a neuroprotective role probably associated with the expression of ERCC6 mRNA.
    Journal of Neuroscience Research 11/2002; 70(2):140-9. · 2.97 Impact Factor
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    ABSTRACT: To study the relationship between tau hyperphosphorylation and the function of glutamate transporter okadaic acid (OA), a protein phosphatase inhibitor, 20 ng in a 0.5 microl volume, was injected into the frontal cortex of rat brain and immunostaining was used to observe the phosphorylation of tau protein and the expression of excitatory amino acid transporter 1 (EAAT1) in the brain following the injection. The results showed that (1) the neurons in the center of the injection region displayed cytoplasmic shrinkage, swelling, nuclear pyknosis, and dislocation at the early stage, and necrosis appeared 3 d after the injection. However, most neurons in the peri-injected areas showed normal morphological characters with immuno positive reaction for AT8, a tau phosphorylated marker; (2) morphological analysis showed that tau hyperphosphorylation caused by OA treatment was mainly observed in the axons and dendrites of neuronal cells at 6 h in the cell body at 1 d, which brought about dystrophic neurites and neurofibrillary tangle (NFT)-like pathological changes; (3) the induction of glutamate transporter EAAT1 was observed in the involved areas corresponding to that with AT8 immunopositive staining, and the number of EAAT1-positive staining cells markedly increased at 12 h (P<0.01), peaked at 1 d (P<0.001), then decreased at 3 d following the injection. Combined with a confocal laser scanning microscopic analysis, double fluorescent immunostaining showed that EAAT1 positive staining appeared in neurons as well as astrocytes in the peri-injected areas of the frontal cortex. These results demonstrate that OA increases glutamate transporter EAAT1 expression in neurons while it induces tau hyperphosphorylation. However, the mechanism and significance of the induction of glutamate transporter EAAT1 expression remain to be further elucidated.
    Sheng li xue bao: [Acta physiologica Sinica] 09/2002; 54(4):287-93.
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    ABSTRACT: In the present study, double fluorescence staining combined with confocal laser scanning microscopy analysis were used to examine the effects of melatonin on ischemia-induced neuronal DNA strand breaks and its possible mechanisms in a transient middle cerebral artery (MCA) occlusion model. Results showed that melatonin dose-dependently reduced infarct areas and decreased both DNA double and single strand breaks (DSB and SSB) and enhanced cell viability in the peri-ischemic brain regions. Furthermore, Bcl-2 induction in the ischemic brain was further enhanced by melatonin treatment. Double staining analysis indicated that the cells costained for Bcl-2 and TdT-mediated-deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL), a DSB marker, displayed a relative regular morphology compared with the cells only stained with TUNEL. Transient ischemia induced an expression of excision repair cross-complementing factor 6 (ERCC6) mRNA, a gene essential for the preferential repair of nuclear excision repair, in the injured neurons. Double labeling showed that ERCC6 only co-localized with proliferating cell nuclear antigen (PCNA), a member of the nuclear excision repair complex, but not with TUNEL. Melatonin further and statistical significantly up-regulated ERCC6 mRNA expression in the peri-ischemic region of rat brains. The results suggest that neuroprotection by melatonin against ischemic injury may be related to modulation of apoptosis and DNA repair capacity.
    Journal of Pineal Research 09/2002; 33(1):48-56. · 7.30 Impact Factor
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    ABSTRACT: Immunohistochemistry and double immunofluorescent labeling techniques combined with confocal laser scanning microscope analysis were used to investigate the characteristic spatial induction profile of nestin following a transient middle cerebral artery occlusion in adult rat brain. The results showed that nestin was induced in ischemic core at 1 day after reperfusion. In addition to ischemic core, the expression of nestin increased in peri-ischemic I, II and III regions at 3 days and 1 week, then it decreased and narrowed along the rim of ischemic core 2 weeks after reperfusion. Double immunofluorescent labeling showed that nestin positive cells were mostly co-stained with GFAP,a astrocyte marker, in peri-ischemic I region 3 days after reperfusion. At 2 weeks, however nestin cells showed a long process and the cells double stained with nestin and NSE,a neuonal specific marker,increased in the ischemic brain. The results suggest that cerebral ischemia induces nestin expression in damaged neurons which might favor the neuroprotection against ischemic damage.
    Sheng li xue bao: [Acta physiologica Sinica] 09/2002; 54(4):294-9.