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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
391

HSPA12B Promotes Functional Recovery After Ischaemic Stroke Through an eNOS-Dependent Mechanism

Zhao, Yanlin, Liu, Chang, Liu, Jiali, Kong, Qiuyue, Mao, Yu, Cheng, Hao, Li, Nan, Zhang, Xioajin, Li, Chuanfu, Li, Yuehua, Liu, Li, Ding, Zhengnian 01 April 2018 (has links)
Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine. Stroke is the leading cause of disability worldwide. HSPA12B, a heat-shock protein recently identified expression specifically in endothelial cells, is able to promote angiogenesis. Here, we have investigated its effects on functional recovery at chronic phase of ischaemic stroke. Ischaemic stroke was induced by 60 min. of middle cerebral artery occlusion in transgenic mice with overexpression of HSPA12B (HSPA12B Tg) and wild-type littermates (WT). HSPA12B Tg mice demonstrated a significant higher survival rate than WT mice within 28 days post-stroke. Significant improved neurological functions, increased spontaneous locomotor activity and decreased anxiety were detected inHSPA12B Tg mice compared with WT controls within 21 days post-stroke. Stroke-induced hippocampal degeneration was attenuated in HSPA12B Tg mice examined at day 28 post-stroke. Interestingly, HSPA12B Tg mice showed enhanced peri-infarct angiogenesis (examined 28 days post-stroke) and hippocampal neurogenesis (examined 7 days post-stroke), respectively, compared to WT mice. The stroke-induced eNOS phosphorylation and TGF-β1 expression were augmented in HSPA12B Tg mice. However, administration with eNOS inhibitor L-NAME diminished the HSPA12B-induced protection in neurological functional recovery and mice survival post-stroke. The data suggest that HSPA12B promoted functional recovery and survival after stroke in an eNOS-dependent mechanism. Targeting HSPA12B expression may have a therapeutic potential for the stroke-evoked functional disability and mortality.
392

Effects of Environmental Factors on Circadian Activity in the Flesh Fly, Sarcophaga Crassipalpis

Joplin, Karl H., Moore, Darrell 01 March 1999 (has links)
The diel locomotor activity patterns of wandering larvae in the flesh fly, Sarcophaga crassipalpis Macquart (Diptera: Sarcophagidae), were examined using a novel apparatus and shown to be primarily diurnal, but with a minority (37%) showing nocturnal activity. In response to the environmental stress of heat shock, a significantly larger proportion (72%) of the larvae became nocturnal. In comparison, adult circadian activity also was predominantly diurnal, but not correlated with the larval activity patterns. In addition, adult patterns showed age-related changes in entrainment and free running period. Finally, the phase of circadian-gated adult eclosion was shown to be entrained by a 3-day exposure to light-dark cycles delivered prior to pupariation, with the phase maintained throughout pupal-adult metamorphosis under constant dark conditions. These results demonstrate that environmental changes may have profound effects on the expression of 24-h activity patterns and circadian rhythms during different life stages throughout development.
393

HSPA12B Attenuates Cardiac Dysfunction and Remodelling After Myocardial Infarction Through an Enos-Dependent Mechanism

Li, Jingjin, Zhang, Yangyang, Li, Chuanfu, Xie, Jian, Liu, Ying, Zhu, Weina, Zhang, Xiaojin, Jiang, Surong, Liu, Li, Ding, Zhengnian 01 September 2013 (has links)
AimsHSPA12B is a newly discovered and endothelial-cell-specifically expressed heat shock protein. We have reported recently that overexpression of HSPA12B increased endothelial nitric oxide synthase (eNOS) expression in mouse cardiac tissues during endotoxemia. Endothelial NOS has been shown to protect heart from ischaemic injury. We hypothesized that overexpression of HSPA12B will attenuate cardiac dysfunction and remodelling after myocardial infarction (MI) through an eNOS-dependant mechanism.Methods and resultsMI was induced by permanent ligation of the left anterior descending coronary artery in the transgenic mice (Tg) overexpressing hspa12b gene and its wild-type (WT) littermates. Echocardiographic analysis revealed that Tg mice exhibited improvements in cardiac dysfunction and remodelling at 1 and 4 weeks after MI. These improvements were accompanied by a significant decrease in cardiomyocyte apoptosis and increase in capillary and arteriolar densities. Significant up-regulation of eNOS, VEGF, Ang-1, and Bcl-2 was also observed in Tg hearts compared with WT hearts after MI. However, pharmacological inhibition of eNOS abolished the HSPA12B-induced decrease in cardiomyocyte apoptosis and increase in capillary formation after MI. Most importantly, inhibition of eNOS abrogated the protection of HSPA12B against cardiac dysfunction and remodelling after MI.ConclusionsThese data demonstrate for the first time that the overexpression of HSPA12B attenuates cardiac dysfunction and remodelling after MI. This action of HSPA12B was mediated, at least in part, by prevention of cardiomyocyte apoptosis and promotion of myocardial angiogenesis via an eNOS-dependent mechanism. HSPA12B could be a novel target for the management of patients with post-MI cardiac dysfunction and remodelling.
394

Overexpression of HSPA12B Protects Against Cerebral Ischemia/Reperfusion Injury via a PI3K/Akt-Dependent Mechanism

Ma, Yujie, Lu, Chen, Li, Chuanfu, Li, Rongrong, Zhang, Yangyang, Ma, He, Zhang, Xiaojin, Ding, Zhengnian, Liu, Li 01 January 2013 (has links)
Background and purpose: HSPA12B is a newly discovered member of the Hsp70 family proteins. This study investigated the effects of HSPA12B on focal cerebral ischemia/reperfusion (I/R) injury in mice. Methods: Transgenic mice overexpressing human HSPA12B (Tg) and wild-type littermates (WT) were subjected to 60. min of middle cerebral artery occlusion to induce ischemia and followed by reperfusion (I/R). Neurological deficits, infarct volumes and neuronal death were examined at 6 and 24. hrs after reperfusion. Blood-brain-barrier (BBB) integrity and activated cellular signaling were examined at 3. hrs after reperfusion. Results: After cerebral I/R, Tg mice exhibited improvement in neurological deficits and decrease in infarct volumes, when compared with WT I/R mice. BBB integrity was significantly preserved in Tg mice following cerebral I/R. Tg mice also showed significant decreases in cell injury and apoptosis in the ischemic hemispheres. We observed that overexpression of HSPA12B activated PI3K/Akt signaling and suppressed JNK and p38 activation following cerebral I/R. Importantly, pharmacological inhibition of PI3K/Akt signaling abrogated the protection against cerebral I/R injury in Tg mice. Conclusions: The results demonstrate that HSPA12B protects the brains from focal cerebral I/R injury. The protective effect of HSPA12B is mediated though a PI3K/Akt-dependent mechanism. Our results suggest that HSPA12B may have a therapeutic potential against ischemic stroke.
395

Differential Translocation or Phosphorylation of Alpha B Crystallin Cannot Be Detected in Ischemically Preconditioned Rabbit Cardiomyocytes

Armstrong, Stephen C., Shivell, Christine L., Ganote, Charles E. 01 January 2000 (has links)
Alpha B Crystallin (αBC) is a putative effector protein of ischemic preconditioning (IPC). that is phosphorylated on Ser 45 by ERK1/2 and Set 59 by the p38 MAPK substrate, MAPKAPK-2. Translocation and phosphorylation of αBC was determined in cytosolic and cytoskeletal fractions by 1D SDS-PAGE and IEF, or using Ser 45 and Set 59 phospho-specific antibodies in: (1) control rabbit cardiomyocytes; (2) cells preconditioned by 10 min in vitro ischemia; or after pre-treatment with specific inhibitors of (3) Ser/Thr protein phosphatase 1/2A (calyculin A); (4) p38 MAPK (SB203580); or (5) ERK 1/2 (PD98059); all prior to 180 min ischemia. Ischemia induced a cytosolic to cytoskeletal translocation of αBC, which was similar in all the groups. Highly phosphorylated isoforms (D1/2) of αBC were present in cytosolic but not cytoskeletal fractions at 0 min ischemia. By 60-90 min ischemia. D1/2 isoforms had translocated to the cytoskeletal fraction. Calyculin A maintained D1/2 levels throughout prolonged ischemia. SB203580 decreased αBC phosphorylation. Neither PD98059 nor IPC altered αBC phosphorylation during prolonged ischemia. It is concluded that αBC phosphorylation during ischemia is regulated by p38 MAPK but not by ERK 1/2. The inability to detect a correlation between IPC protection and either αBC translocation or phosphorylation suggests that the proteins in the highly phosphorylated isoform bands of αBC quantitated in this study are not protective end effectors of classical IPC.
396

HSPA12B Attenuates Cardiac Dysfunction and Remodelling After Myocardial Infarction Through an Enos-Dependent Mechanism

Li, Jingjin, Zhang, Yangyang, Li, Chuanfu, Xie, Jian, Liu, Ying, Zhu, Weina, Zhang, Xiaojin, Jiang, Surong, Liu, Li, Ding, Zhengnian 01 September 2013 (has links)
AimsHSPA12B is a newly discovered and endothelial-cell-specifically expressed heat shock protein. We have reported recently that overexpression of HSPA12B increased endothelial nitric oxide synthase (eNOS) expression in mouse cardiac tissues during endotoxemia. Endothelial NOS has been shown to protect heart from ischaemic injury. We hypothesized that overexpression of HSPA12B will attenuate cardiac dysfunction and remodelling after myocardial infarction (MI) through an eNOS-dependant mechanism.Methods and resultsMI was induced by permanent ligation of the left anterior descending coronary artery in the transgenic mice (Tg) overexpressing hspa12b gene and its wild-type (WT) littermates. Echocardiographic analysis revealed that Tg mice exhibited improvements in cardiac dysfunction and remodelling at 1 and 4 weeks after MI. These improvements were accompanied by a significant decrease in cardiomyocyte apoptosis and increase in capillary and arteriolar densities. Significant up-regulation of eNOS, VEGF, Ang-1, and Bcl-2 was also observed in Tg hearts compared with WT hearts after MI. However, pharmacological inhibition of eNOS abolished the HSPA12B-induced decrease in cardiomyocyte apoptosis and increase in capillary formation after MI. Most importantly, inhibition of eNOS abrogated the protection of HSPA12B against cardiac dysfunction and remodelling after MI.ConclusionsThese data demonstrate for the first time that the overexpression of HSPA12B attenuates cardiac dysfunction and remodelling after MI. This action of HSPA12B was mediated, at least in part, by prevention of cardiomyocyte apoptosis and promotion of myocardial angiogenesis via an eNOS-dependent mechanism. HSPA12B could be a novel target for the management of patients with post-MI cardiac dysfunction and remodelling.
397

Overexpression of HSPA12B Protects Against Cerebral Ischemia/Reperfusion Injury via a PI3K/Akt-Dependent Mechanism

Ma, Yujie, Lu, Chen, Li, Chuanfu, Li, Rongrong, Zhang, Yangyang, Ma, He, Zhang, Xiaojin, Ding, Zhengnian, Liu, Li 01 January 2013 (has links)
Background and purpose: HSPA12B is a newly discovered member of the Hsp70 family proteins. This study investigated the effects of HSPA12B on focal cerebral ischemia/reperfusion (I/R) injury in mice. Methods: Transgenic mice overexpressing human HSPA12B (Tg) and wild-type littermates (WT) were subjected to 60. min of middle cerebral artery occlusion to induce ischemia and followed by reperfusion (I/R). Neurological deficits, infarct volumes and neuronal death were examined at 6 and 24. hrs after reperfusion. Blood-brain-barrier (BBB) integrity and activated cellular signaling were examined at 3. hrs after reperfusion. Results: After cerebral I/R, Tg mice exhibited improvement in neurological deficits and decrease in infarct volumes, when compared with WT I/R mice. BBB integrity was significantly preserved in Tg mice following cerebral I/R. Tg mice also showed significant decreases in cell injury and apoptosis in the ischemic hemispheres. We observed that overexpression of HSPA12B activated PI3K/Akt signaling and suppressed JNK and p38 activation following cerebral I/R. Importantly, pharmacological inhibition of PI3K/Akt signaling abrogated the protection against cerebral I/R injury in Tg mice. Conclusions: The results demonstrate that HSPA12B protects the brains from focal cerebral I/R injury. The protective effect of HSPA12B is mediated though a PI3K/Akt-dependent mechanism. Our results suggest that HSPA12B may have a therapeutic potential against ischemic stroke.
398

Class III PI3K-Mediated Prolonged Activation of Autophagy Plays a Critical Role in the Transition of Cardiac Hypertrophy to Heart Failure

Yu, Peng, Zhang, Yangyang, Li, Chuanfu, Li, Yuehua, Jiang, Surong, Zhang, Xiaojin, Ding, Zhengnian, Tu, Fei, Wu, Jun, Gao, Xiang, Li, Liu 01 July 2015 (has links)
Pathological cardiac hypertrophy often leads to heart failure. Activation of autophagy has been shown in pathological hypertrophic hearts. Autophagy is regulated positively by Class III phosphoinositide 3-kinase (PI3K). However, it is unknown whether Class III PI3K plays a role in the transition of cardiac hypertrophy to heart failure. To address this question, we employed a previously established cardiac hypertrophy model in heat shock protein 27 transgenic mice which shares common features with several types of human cardiomyopathy. Age-matched wild-type mice served as control. Firstly, a prolonged activation of autophagy, as reflected by autophagosome accumulation, increased LC3 conversion and decreased p62 protein levels, was detected in hypertrophic hearts from adaptive stage to maladaptive stage. Moreover, morphological abnormalities in myofilaments and mitochondria were presented in the areas accumulated with autophagosomes. Secondly, activation of Class III PI3K Vacuolar protein sorting 34 (Vps34), as demonstrated by upregulation of Vps34 expression, increased interaction of Vps34 with Beclin-1, and deceased Bcl-2 expression, was demonstrated in hypertrophic hearts from adaptive stage to maladaptive stage. Finally, administration with Wortmaninn, a widely used autophagy inhibitor by suppressing Class III PI3K activity, significantly decreased autophagy activity, improved morphologies of intracellular apartments, and most importantly, prevented progressive cardiac dysfunction in hypertrophic hearts. Collectively, we demonstrated that Class III PI3K plays a central role in the transition of cardiac hypertrophy to heart failure via a prolonged activation of autophagy in current study. Class III PI3K may serve as a potential target for the treatment and management of maladaptive cardiac hypertrophy.
399

HSPA12B Inhibits Lipopolysaccharide-Induced Inflammatory Response in Human Umbilical Vein Endothelial Cells

Wu, Jun, Li, Xuehan, Huang, Lei, Jiang, Surong, Tu, Fei, Zhang, Xiaojin, Ma, He, Li, Rongrong, Li, Chuanfu, Li, Yuehua, Ding, Zhengnian, Liu, Li 01 January 2015 (has links)
Heat shock protein A12B (HSPA12B) is a newly discovered member of the HSP70 protein family. This study investigated the effects of HSPA12B on lipopolysaccharide (LPS)-induced inflammatory responses in human umbilical vein endothelial cells (HUVECs) and the possible mechanisms involved. A HUVECs inflammatory model was induced by LPS. Overexpression of HSPA12B in HUVECs was achieved by infection with recombinant adenoviruses encoding green fluorescence protein-HSPA12B. Knockdown of HSPA12B was achieved by siRNA technique. Twenty four hours after virus infection or siRNA transfection, HUVECs were stimulated with 1 μg/ml LPS for 4 hrs. Endothelial cell permeability ability was determined by transwell permeability assay. The binding rate of human neutrophilic polymorphonuclear leucocytes (PMN) with HUVECs was examined using myeloperoxidase assay. Cell migrating ability was determined by the wound-healing assay. The mRNA and protein expression levels of interested genes were analyzed by RT-qPCR and Western blot, respectively. The release of cytokines interleukin-6 and tumour necrosis factor-α was measured by ELISA. HSPA12B suppressed LPS-induced HUVEC permeability and reduced PMN adhesion to HUVECs. HSPA12B also inhibited LPS-induced up-regulation of adhesion molecules and inflammatory cytokine expression. By contrast, knockdown of HSPA12B enhanced LPS-induced increases in the expression of adhesion molecules and inflammatory cytokines. Moreover, HSPA12B activated PI3K/Akt signalling pathway and pharmacological inhibition of this pathway by Wortmannin completely abrogated the protection of HSPA12B against inflammatory response in HUVECs. Our results suggest that HSPA12B attenuates LPS-induced inflammatory responses in HUVECs via activation of PI3K/Akt signalling pathway.
400

Over-Expression of Heat Shock Protein 27 Attenuates Doxorubicin-Induced Cardiac Dysfunction in Mice

Liu, Li, Zhang, Xiaojin, Qian, Bo, Min, Xiaoyan, Gao, Xiang, Li, Chuanfu, Cheng, Yunlin, Huang, Jun 01 August 2007 (has links)
Background: Oxidative stress and myocyte apoptosis are thought to play an important role in the pathogenesis, progression and prognosis of heart failure (HF). Heat shock protein 27 (Hsp27) has been found to confer resistance to oxidative stress in cultured cells; however, the role of Hsp27 in in-vivo hearts remains to be determined. Aim: To investigate the effects of Hsp27 over-expression on doxorubicin-induced HF. Methods and Results: Transgenic mice (TG) with cardiac specific over-expression of Hsp27 and their wild type littermates (WT) were challenged with doxorubicin (25 mg/kg, IP) to induce HF. At day 5, TG mice had significantly improved cardiac function and viability and decreased loss of heart weight following doxorubicin exposure compared with WT. In another parallel experiment, doxorubicin-induced increased levels of reactive oxygen species, protein carbonylation, apoptosis and morphologic changes were detected in the mitochondria in WT hearts, whereas these effects were markedly attenuated in TG hearts. In addition, upregulation of heat shock protein 70 and heme oxygenase-1 was present in the TG hearts after doxorubicin stimulation in comparison to WT hearts. Conclusion: These findings indicate that Hsp27 may play a key role in resistance to doxorubicin-induced cardiac dysfunction.

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