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76 result(s) for "Fan, Yan-Ying"
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Delayed CO2 postconditioning promotes neurological recovery after cryogenic traumatic brain injury by downregulating IRF7 expression
AimsFew treatments are available in the subacute phase of traumatic brain injury (TBI) except rehabilitation training. We previously reported that transient CO2 inhalation applied within minutes after reperfusion has neuroprotective effects against cerebral ischemia/reperfusion injury. In this study, it was hypothesized that delayed CO2 postconditioning (DCPC) starting at the subacute phase may promote neurological recovery of TBI.MethodsUsing a cryogenic TBI (cTBI) model, mice received DCPC daily by inhaling 5%/10%/20% CO2 for various time-courses (one/two/three cycles of 10-min inhalation/10-min break) at Days 3–7, 3–14 or 7–18 after cTBI. Beam walking and gait tests were used to assess the effect of DCPC. Lesion size, expression of GAP-43 and synaptophysin, amoeboid microglia number and glia scar area were detected. Transcriptome and recombinant interferon regulatory factor 7 (Irf7) adeno-associated virus were applied to investigate the molecular mechanisms.ResultsDCPC significantly promoted recovery of motor function in a concentration and time-course dependent manner with a wide therapeutic time window of at least 7 days after cTBI. The beneficial effects of DCPC were blocked by intracerebroventricular injection of NaHCO3. DCPC also increased puncta density of GAP-43 and synaptophysin, and reduced amoeboid microglia number and glial scar formation in the cortex surrounding the lesion. Transcriptome analysis showed many inflammation-related genes and pathways were altered by DCPC, and Irf7 was a hub gene, while overexpression of IRF7 blocked the motor function improvement of DCPC.ConclusionsWe first showed that DCPC promoted functional recovery and brain tissue repair, which opens a new therapeutic time window of postconditioning for TBI. Inhibition of IRF7 is a key molecular mechanism for the beneficial effects of DCPC, and IRF7 may be a potential therapeutic target for rehabilitation after TBI.
Activation of the Central Histaminergic System is Involved in Hypoxia-Induced Stroke Tolerance in Adult Mice
We hypothesized that activation of the central histaminergic system is required for neuroprotection induced by hypoxic preconditioning. Wild-type (WT) and histidine decarboxylase knockout (HDC-KO) mice were preconditioned by 3 hours of hypoxia (8% O2) and, 48 hours later, subjected to 30 minutes of middle cerebral artery (MCA) occlusion, followed by 24 hours of reperfusion. Hypoxic preconditioning improved neurologic function and decreased infarct volume in WT or HDC-KO mice treated with histamine, but not in HDC-KO or WT mice treated with α-fluoromethylhistidine (α-FMH, an inhibitor of HDC). Laser-Doppler flowmetry analysis showed that hypoxic preconditioning ameliorated cerebral blood flow (CBF) in the periphery of the MCA territory during ischemia in WT mice but not in HDC-KO mice. Histamine decreased in the cortex of WT mice after 2, 3, and 4 hours of hypoxia, and HDC activity increased after 3 hours of hypoxia. Vascular endothelial growth factor (VEGF) mRNA and protein expressions showed a greater increase after hypoxia than those in HDC-KO or α-FMH-treated WT mice. In addition, the VEGF receptor-2 antagonist SU1498 prevented the protective effect of hypoxic preconditioning in infarct volume and reversed increased peripheral CBF in WT mice. Therefore, endogenous histamine is an essential mediator of hypoxic preconditioning. It may function by enhancing hypoxia-induced VEGF expression.
Diurnal Characteristics of the Orexin System Genes and Its Effects on Pathology at Early Stage in 3xTg-AD Mice
Orexin and its receptors are closely related to the pathogenesis of Alzheimer’s disease (AD). Although the expression of orexin system genes under physiological condition has circadian rhythm, the diurnal characteristics of orexin system genes, and its potential role in the pathogenesis in AD are unknown. In the present study, we hope to elucidate the diurnal characteristics of orexin system genes at the early stage of AD, and to investigate its potential role in the development of AD neuropathology. We firstly detected the mRNA levels of orexin system genes, AD risk genes and core clock genes (CCGs) in hypothalamus and hippocampus in 6-month-old male 3xTg-AD mice and C57BL/6J (wild type, WT) control mice, then analyzed diurnal expression profiles of all genes using JTK_CYCLE algorithm, and did the correlation analysis between expression of orexin system genes and AD risk genes or CCGs. In addition, the expression of β-amyloid protein (Aβ) and phosphorylated tau (p-tau) protein were measured. The results showed that the diurnal mRNA expression profiles of PPO, OX1R, OX2R, Bace2, Bmal1, Per1, Per2 and Cry1 in the hypothalamus, and gene expression of OX1R, OX2R, Bace1, Bmal1, Per1 and Cry2 in the hippocampus in 3xTg-AD mice were different from that in WT mice. Furthermore, there is positive correlation between orexin system genes and AD risk genes or CCGs in the brain in 3xTg-AD mice. In addition, the expression of Aβ and p-tau in hippocampus in 3xTg-AD mice were significantly increased, and the expression of p-tau is higher in night than in day. These results indicate that the abnormal expression profiles of orexin system genes and its interaction with AD risk genes or CCGs might exert important role in the pathogenesis of AD, which will increase the expression of Aβ and p-tau, and accelerate the development of AD.
A Novel Neuroprotective Strategy for Ischemic Stroke: Transient Mild Acidosis Treatment by CO2 Inhalation at Reperfusion
Acidosis is one of the key components in cerebral ischemic postconditioning that has emerged recently as an endogenous strategy for neuroprotection. We set out to test whether acidosis treatment at reperfusion can protect against cerebral ischemia/reperfusion injury. Adult male C57BL/6 J mice were subjected to 60-minute middle cerebral arterial occlusion followed by 24-hour reperfusion. Acidosis treatment by inhaling 10%, 20%, or 30% CO2 for 5 or 10 minutes at 5, 50, or 100 minutes after reperfusion was applied. Our results showed that inhaling 20% CO2 for 5 minutes at 5 minutes after reperfusion-induced optimal neuroprotection, as revealed by reduced infarct volume. Attenuating brain acidosis with NaHCO3 significantly compromised the acidosis or ischemic postconditioning-induced neuroprotection. Consistently, both acidosis-treated primary cultured cortical neurons and acute corticostriatal slices were more resistant to oxygen–glucose deprivation/reperfusion insult. In addition, acidosis inhibited ischemia/reperfusion-induced apoptosis, caspase-3 expression, cytochrome c release to cytoplasm, and mitochondrial permeability transition pore (mPTP) opening. The neuroprotection of acidosis was inhibited by the mPTP opener atractyloside both in vivo and in vitro. Taken together, these findings indicate that transient mild acidosis treatment at reperfusion protects against cerebral ischemia/reperfusion injury. This neuroprotection is likely achieved, at least partly, by inhibiting mPTP opening and mitochondria-dependent apoptosis.
Delayed Chronic Acidic Postconditioning Improves Poststroke Motor Functional Recovery and Brain Tissue Repair by Activating Proton-Sensing TDAG8
Acidic postconditioning by transient CO 2 inhalation applied within minutes after reperfusion has neuroprotective effects in the acute phase of stroke. However, the effects of delayed chronic acidic postconditioning (DCAPC) initiated during the subacute phase of stroke or other acute brain injuries are unknown. Mice received daily DCAPC by inhaling 5%/10%/20% CO 2 for various durations (three cycles of 10- or 20-min CO 2 inhalation/10-min break) at days 3–7, 7–21, or 3–21 after photothrombotic stroke. Grid-walk, cylinder, and gait tests were used to assess motor function. DCAPC with all CO 2 concentrations significantly promoted motor functional recovery, even when DCAPC was delayed for 3–7 days. DCAPC enhanced the puncta density of GAP-43 (a marker of axon growth and regeneration) and synaptophysin (a marker of synaptogenesis) and reduced the amoeboid microglia number, glial scar thickness and mRNA expression of CD16 and CD32 (markers of proinflammatory M1 microglia) compared with those of the stroke group. Cerebral blood flow (CBF) increased in response to DCAPC. Furthermore, the mRNA expression of TDAG8 (a proton-activated G-protein-coupled receptor) was increased during the subacute phase of stroke, while DCAPC effects were blocked by systemic knockout of TDAG8, except for those on CBF. DCAPC reproduced the benefits by re-expressing TDAG8 in the peri-infarct cortex of TDAG8-/- mice infected with HBAAV2/9-CMV-TDAG8-3flag-ZsGreen. Taken together, we first showed that DCAPC promoted functional recovery and brain tissue repair after stroke with a wide therapeutic time window of at least 7 days after stroke. Brain-derived TDAG8 is a direct target of DCAPC that induces neuroreparative effects.
Delayed CO 2 postconditioning promotes neurological recovery after cryogenic traumatic brain injury by downregulating IRF7 expression
Few treatments are available in the subacute phase of traumatic brain injury (TBI) except rehabilitation training. We previously reported that transient CO inhalation applied within minutes after reperfusion has neuroprotective effects against cerebral ischemia/reperfusion injury. In this study, it was hypothesized that delayed CO postconditioning (DCPC) starting at the subacute phase may promote neurological recovery of TBI. Using a cryogenic TBI (cTBI) model, mice received DCPC daily by inhaling 5%/10%/20% CO for various time-courses (one/two/three cycles of 10-min inhalation/10-min break) at Days 3-7, 3-14 or 7-18 after cTBI. Beam walking and gait tests were used to assess the effect of DCPC. Lesion size, expression of GAP-43 and synaptophysin, amoeboid microglia number and glia scar area were detected. Transcriptome and recombinant interferon regulatory factor 7 (Irf7) adeno-associated virus were applied to investigate the molecular mechanisms. DCPC significantly promoted recovery of motor function in a concentration and time-course dependent manner with a wide therapeutic time window of at least 7 days after cTBI. The beneficial effects of DCPC were blocked by intracerebroventricular injection of NaHCO . DCPC also increased puncta density of GAP-43 and synaptophysin, and reduced amoeboid microglia number and glial scar formation in the cortex surrounding the lesion. Transcriptome analysis showed many inflammation-related genes and pathways were altered by DCPC, and Irf7 was a hub gene, while overexpression of IRF7 blocked the motor function improvement of DCPC. We first showed that DCPC promoted functional recovery and brain tissue repair, which opens a new therapeutic time window of postconditioning for TBI. Inhibition of IRF7 is a key molecular mechanism for the beneficial effects of DCPC, and IRF7 may be a potential therapeutic target for rehabilitation after TBI.
Characterization of SARS-CoV-specific memory T cells from recovered individuals 4 years after infection
SARS-CoV infection of human results in antigen-specific cellular and humoral immune responses. However, it is critical to determine whether SARS-CoV-specific memory T cells can persist for long periods of time. In this study, we analyzed the cellular immune response from 21 SARS-recovered individuals who had been diagnosed with SARS in 2003 by using ELISA, CBA, ELISpot and multiparameter flow cytometry assays. Our results demonstrated that low levels of specific memory T cell responses to SARS-CoV S, M, E and N peptides were detected in a proportion of SARS-recovered patients, and IFN-γ was the predominant cytokine produced by T cells after stimulation with peptides. Cytometry analysis indicated that the majority of memory CD8⁺ T cells produced IFN-γ, whereas memory CD4⁺ T cells produced IFN-γ, IL-2 or TNF-α. These results might provide valuable information on the cellular immune response in recovered SARS-CoV patients for the rational design of vaccines against SARS-CoV infection.
Oocyte-expressed yes-associated protein is a key activator of the early zygotic genome in mouse
In early mammalian embryos, the genome is transcriptionally quiescent until the zygotic genome activation (ZGA) which occurs 2-3 days after fertilization. Despite a long-standing effort, maternal transcription factors regulating this crucial developmental event remain largely elusive. Here, using maternal and paternal mouse models of Yapl deletion, we show that maternally accumulated yes-associated protein (YAP) in oocyte is essential for ZGA. Maternal Yapl-knoekout embryos exhibit a prolonged two-cell stage and develop into the four-cell stage at a much slower pace than the wild-type controls. Transcriptome analyses identify YAP target genes in early blastomeres; two of which, Rp113 and Rrm2, are required to mediate maternal YAP's effect in conferring developmental competence on preim- plantation embryos. Furthermore, the physiological YAP activator, lysophosphatidic acid, can substantially improve early development of wild-type, but not maternal Yapl-knockout embryos in both oviduct and culture. These obser- vations provide insights into the mechanisms of ZGA, and suggest potentials of YAP activators in improving the de- velopmental competence of cultured embryos in assisted human reproduction and animal biotechnology.
Neuroprotection by sodium ferulate against glutamate-induced apoptosis is mediated by ERK and P13 kinase pathways
Aim: To investigate whether sodium ferulate (SF) can protect cortical neurons from glutamate-induced neurotoxicity and the mechanisms responsible for this protection. Methods: Cultured cortical neurons were incubated with 50 μmol/L glutamate for either 30 min or 24 h, with or without pre-incubation with SF (100, 200, and 500 pmol/L, respectively). LY294002, wortmannin, PD98059, and U0126 were added respectively to the cells 1 h prior to SF treatment. After incubation with glutamate for 24 h, neuronal apoptosis was quantified by scoring the per- centage of cells with apoptotic nuclear morphology after Hoechst 33258 staining. After incubation with glutamate for either 30 rain or 24 h, cellular extracts were prepared for Western blotting of active caspase-3, poly (ADP-ribose) polymerase (PARP), μ-calpain, Bcl-2, phospho-Akt, phosphorylated ribosomal protein S6 pro- tein kinase (p70S6K), phospho-mitogen-activated protein kinase kinase (MEK1/2) and phosphorylated extracellular signal-regulated kinase (ERK) 1/2. Results: SF reduced glutamate-evoked apoptotic morphology, active caspase-3 protein expression, and PARP cleavage and inhibited the glutamate-induced upregulation of the ~-calpain protein level. The inhibition of the phosphatidylinositol 3-kinase (P13K) and the MEK/ERK1/2 pathways partly abrogated the protective effect of SF against glutamate-induced neuronal apoptosis. SF prevented the glutamate- induced decrease in the activity of the PI3K/Akt/p70S6K and the MEK/ERK1/2 pathways. Moreover, incubation of cortical neurons with SF for 30 min inhibited the reduction of the Bcl-2 expression induced by glutamate. Conclusion: The results indicate that PI3K/Akt/p70S6K and the MEK/ERK signaling pathways play important roles in the protective effect of SF against glutamate toxicity in cortical neurons.
A novel neuroprotective strategy for ischemic stroke: transient mild acidosis treatment by CO sub(2) inhalation at reperfusion
Acidosis is one of the key components in cerebral ischemic postconditioning that has emerged recently as an endogenous strategy for neuroprotection. We set out to test whether acidosis treatment at reperfusion can protect against cerebral ischemia/reperfusion injury. Adult male C57BL/6 J mice were subjected to 60-minute middle cerebral arterial occlusion followed by 24-hour reperfusion. Acidosis treatment by inhaling 10%, 20%, or 30% CO sub(2) for 5 or 10 minutes at 5, 50, or 100 minutes after reperfusion was applied. Our results showed that inhaling 20% CO sub(2) for 5 minutes at 5 minutes after reperfusion-induced optimal neuroprotection, as revealed by reduced infarct volume. Attenuating brain acidosis with NaHCO sub(3) significantly compromised the acidosis or ischemic postconditioning-induced neuroprotection. Consistently, both acidosis-treated primary cultured cortical neurons and acute corticostriatal slices were more resistant to oxygen-glucose deprivation/reperfusion insult. In addition, acidosis inhibited ischemia/reperfusion-induced apoptosis, caspase-3 expression, cytochrome c release to cytoplasm, and mitochondrial permeability transition pore (mPTP) opening. The neuroprotection of acidosis was inhibited by the mPTP opener atractyloside both in vivo and in vitro. Taken together, these findings indicate that transient mild acidosis treatment at reperfusion protects against cerebral ischemia/reperfusion injury. This neuroprotection is likely achieved, at least partly, by inhibiting mPTP opening and mitochondria-dependent apoptosis.