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Chi OZ, Mellender SJ, Kiss GK, Liu X, Weiss HR. Blood -brain barrier disruption was less under isoflurane than pentobarbital anesthesia via a PI3K/Akt pathway in early cerebral ischemia. Brain Res Bull 2017; 131:1-6. [PMID: 28238830 DOI: 10.1016/j.brainresbull.2017.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/19/2017] [Accepted: 02/21/2017] [Indexed: 01/07/2023]
Abstract
One of the important factors altering the degree of blood-brain barrier (BBB) disruption in cerebral ischemia is the anesthetic used. The phosphoinositide 3-kinase (PI3K)/Akt signaling pathway has been reported to be involved in modulating BBB permeability and in isoflurane induced neuroprotection. This study was performed to compare the degree of BBB disruption in focal cerebral ischemia under isoflurane vs pentobarbital anesthesia and to determine whether inhibition of PI3K/Akt would affect the disruption in the early stage of focal cerebral ischemia. Permanent middle cerebral artery (MCA) occlusion was performed in rats under 1.4% isoflurane or pentobarbital (50mg/kg i.p.) anesthesia with controlled ventilation. In half of each group LY294002, which is a PI3K/Akt inhibitor, was applied on the ischemic cortex immediately after MCA occlusion. After one hour of MCA occlusion, the transfer coefficient (Ki) of 14C-α-aminoisobutyric acid (14C-AIB) was determined to quantify the degree of BBB disruption. MCA occlusion increased the Ki both in the isoflurane and pentobarbital anesthetized rats. However, the value of Ki was lower under isoflurane (11.5±6.0μL/g/min) than under pentobarbital (18.3±7.1μL/g/min) anesthesia. The Ki of the contralateral cortex of the pentobarbital group was higher (+74%) than that of the isoflurane group. Application of LY294002 on the ischemic cortex increased the Ki (+99%) only in the isoflurane group. The degree of BBB disruption by MCA occlusion was significantly lower under isoflurane than pentobarbital anesthesia in the early stage of cerebral ischemia. Our data demonstrated the importance of choice of anesthetics and suggest that PI3K/Akt signaling pathway plays a significant role in altering BBB disruption in cerebral ischemia during isoflurane but not during pentobarbital anesthesia.
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Affiliation(s)
- Oak Z Chi
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, 125 Paterson Street, Suite 3100, New Brunswick, NJ, 08901-1977, USA.
| | - Scott J Mellender
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, 125 Paterson Street, Suite 3100, New Brunswick, NJ, 08901-1977, USA
| | - Geza K Kiss
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, 125 Paterson Street, Suite 3100, New Brunswick, NJ, 08901-1977, USA
| | - Xia Liu
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, 125 Paterson Street, Suite 3100, New Brunswick, NJ, 08901-1977, USA
| | - Harvey R Weiss
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ, 08854, USA
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Li J, Chen G, Gao X, Shen C, Zhou P, Wu X, Che X, Xie R. p53 participates in the protective effects of ischemic post-conditioning against OGD-reperfusion injury in primary cultured spinal cord neurons. Neurosci Lett 2017; 638:129-134. [DOI: 10.1016/j.neulet.2016.12.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/10/2016] [Accepted: 12/15/2016] [Indexed: 12/25/2022]
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ConBr, A Lectin Purified from the Seeds of Canavalia brasiliensis, Protects Against Ischemia in Organotypic Culture of Rat Hippocampus: Potential Implication of Voltage-Gated Calcium Channels. Neurochem Res 2016; 42:347-359. [DOI: 10.1007/s11064-016-2078-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 09/22/2016] [Accepted: 10/04/2016] [Indexed: 12/13/2022]
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54
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The mTOR signalling cascade: paving new roads to cure neurological disease. Nat Rev Neurol 2016; 12:379-92. [PMID: 27340022 DOI: 10.1038/nrneurol.2016.81] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Defining the multiple roles of the mechanistic (formerly 'mammalian') target of rapamycin (mTOR) signalling pathway in neurological diseases has been an exciting and rapidly evolving story of bench-to-bedside translational research that has spanned gene mutation discovery, functional experimental validation of mutations, pharmacological pathway manipulation, and clinical trials. Alterations in the dual contributions of mTOR - regulation of cell growth and proliferation, as well as autophagy and cell death - have been found in developmental brain malformations, epilepsy, autism and intellectual disability, hypoxic-ischaemic and traumatic brain injuries, brain tumours, and neurodegenerative disorders. mTOR integrates a variety of cues, such as growth factor levels, oxygen levels, and nutrient and energy availability, to regulate protein synthesis and cell growth. In line with the positioning of mTOR as a pivotal cell signalling node, altered mTOR activation has been associated with a group of phenotypically diverse neurological disorders. To understand how altered mTOR signalling leads to such divergent phenotypes, we need insight into the differential effects of enhanced or diminished mTOR activation, the developmental context of these changes, and the cell type affected by altered signalling. A particularly exciting feature of the tale of mTOR discovery is that pharmacological mTOR inhibitors have shown clinical benefits in some neurological disorders, such as tuberous sclerosis complex, and are being considered for clinical trials in epilepsy, autism, dementia, traumatic brain injury, and stroke.
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Chen WY, Mao FC, Liu CH, Kuan YH, Lai NW, Wu CC, Chen CJ. Chromium supplementation improved post-stroke brain infarction and hyperglycemia. Metab Brain Dis 2016; 31:289-97. [PMID: 26477944 DOI: 10.1007/s11011-015-9749-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/11/2015] [Indexed: 12/17/2022]
Abstract
Hyperglycemia is common after acute stroke and is associated with a worse outcome of stroke. Thus, a better understanding of stress hyperglycemia is helpful to the prevention and therapeutic treatment of stroke. Chromium is an essential nutrient required for optimal insulin activity and normal carbohydrate and lipid metabolism. Beyond its nutritional effects, dietary supplement of chromium causes beneficial outcomes against several diseases, in particular diabetes-associated complications. In this study, we investigated whether post-stroke hyperglycemia involved chromium dynamic mobilization in a rat model of permanent focal cerebral ischemia and whether dietary supplement of chromium improved post-stroke injury and alterations. Stroke rats developed brain infarction, hyperglycemia, hyperinsulinemia, glucose intolerance, and insulin resistance. Post-stroke hyperglycemia was accompanied by elevated secretion of counter-regulatory hormones including glucagon, corticosterone, and norepinephrine, decreased insulin signaling in skeletal muscles, and increased hepatic gluconeogenesis. Correlation studies revealed that counter-regulatory hormone secretion showed a positive correlation with chromium loss and blood glucose increased together with chromium loss. Daily chromium supplementation increased tissue chromium levels, attenuated brain infarction, improved hyperglycemia, and decreased plasma levels of glucagon and corticosterone in stroke rats. Our findings suggest that stroke rats show disturbance of tissue chromium homeostasis with a net loss through urinary excretion and chromium mobilization and loss might be an alternative mechanism responsible for post-stroke hyperglycemia.
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Affiliation(s)
- Wen-Ying Chen
- Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Frank Chiahung Mao
- Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Chia-Hsin Liu
- Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Yu-Hsiang Kuan
- Department of Pharmacology, Chung Shan Medical University, Taichung, Taiwan
| | - Nai-Wei Lai
- Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Chih-Cheng Wu
- Department of Anesthesiology, Taichung Veterans General Hospital, Taichung, Taiwan
- Department of Financial and Computational Mathematics, Providence University, Taichung, Taiwan
| | - Chun-Jung Chen
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.
- Department of Medical Research, Taichung Veterans General Hospital, No. 1650, Sec. 4, Taiwan Boulevard, Taichung City, 407, Taiwan.
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Chi OZ, Mellender SJ, Barsoum S, Liu X, Damito S, Weiss HR. Effects of rapamycin pretreatment on blood-brain barrier disruption in cerebral ischemia-reperfusion. Neurosci Lett 2016; 620:132-6. [PMID: 27037216 DOI: 10.1016/j.neulet.2016.03.053] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 03/12/2016] [Accepted: 03/28/2016] [Indexed: 02/06/2023]
Abstract
The mammalian target of rapamycin (mTOR) pathway is essential in neuronal survival and repair in cerebral ischemia. Decreases in blood-brain barrier (BBB) disruption are associated with a decrease in neuronal damage in cerebral ischemia. This study was performed to investigate how pre-inhibition of the mTOR pathway with rapamycin would affect BBB disruption and the size of the infarcted cortical area in the early stage of focal cerebral ischemia-reperfusion using quantitative analysis of BBB disruption. Rats were treated with 20mg/kg of rapamycin i.p. once a day for 2days (Rapamycin Group) or vehicle (Control Group) before transient middle cerebral artery (MCA) occlusion. After one hour of MCA occlusion and two hours of reperfusion, the transfer coefficient (Ki) of (14)C-α-aminoisobutyric acid ((14)C-AIB) to measure the degree of BBB disruption and the size of the cortical infarct were determined. Ischemia-reperfusion increased the Ki in the Rapamycin treated (+15%) as well as in the untreated control group (+13%). However, rapamycin pretreatment moderately decreased Ki in the contralateral (-30%) as well as in the ischemic-reperfused (-29%) cortex when compared with the untreated control group. Rapamycin pretreatment substantially increased the percentage of cortical infarct compared with the control group (+56%). Our data suggest that activation of mTOR pathway is necessary for neuronal survival in the early stage of cerebral ischemia-perfusion and that the reason for the enlarged cortical infarct by rapamycin pretreatment may be related to its non-BBB effects on the mTOR pathway.
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Affiliation(s)
- Oak Z Chi
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
| | - Scott J Mellender
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Sylviana Barsoum
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Xia Liu
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Stacey Damito
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Harvey R Weiss
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
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Yuan H, Denton K, Liu L, Li XJ, Benashski S, McCullough L, Li J. Nuclear translocation of histone deacetylase 4 induces neuronal death in stroke. Neurobiol Dis 2016; 91:182-93. [PMID: 26969532 DOI: 10.1016/j.nbd.2016.03.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 02/08/2016] [Accepted: 03/07/2016] [Indexed: 10/22/2022] Open
Abstract
Mounting evidence suggests that epigenetic modifications play critical roles in the survival/death of stressed neurons. Chief among these modifications is the deacetylation of histones within the chromatin by histone deacetylases (HDACs). HDAC4 is highly expressed in neurons and is usually trapped in cytosol. However, tightly regulated signal-dependent shuttling of this molecule between cytosol and nucleus occurs. Here, we studied the intracellular trafficking of HDAC4 and regulatory mechanisms during stroke. HDAC4 translocated from the cytosol into the nucleus of neurons in response to stroke induced by middle cerebral artery occlusion (MCAO) in mice. Similar translocation was seen after oxygen-glucose deprivation (OGD) in cultured mouse neurons. Expression of nuclear-restricted HDAC4 increased neuronal death after OGD and worsened infarcts and functional deficits in mice following MCAO; however, expression of cytosolic-restricted HDAC4 did not affect outcome after ischemia. In contrast, HDAC4 knockdown with siRNA improved neuronal survival after OGD. Furthermore, expression of nuclear-restricted HDAC4 reduced the acetylation of histones 3 and 4 as well as the levels of pro-survival downstream molecules after OGD. Finally, genetic deletion of calcium/calmodulin-dependent protein kinase IV (CaMKIV) increased the nuclear accumulation of HDAC4 in MCAO model, while overexpression of CaMKIV reduced the levels of nuclear HDAC4 following OGD. When HDAC4 was inhibited, the neuroprotection provided by CaMKIV overexpression was absent during OGD. Our data demonstrate a detrimental role of the nuclear accumulation of HDAC4 following stroke and identify CaMKIV as a key regulator of neuronal intracellular HDAC4 trafficking during stroke.
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Affiliation(s)
- Hui Yuan
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Kyle Denton
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Lin Liu
- Department of Neurology, University of Texas Health Science Center, Houston, TX, United States
| | - Xue-Jun Li
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Sharon Benashski
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Louise McCullough
- Department of Neurology, University of Texas Health Science Center, Houston, TX, United States
| | - Jun Li
- Department of Neurology, University of Texas Health Science Center, Houston, TX, United States.
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58
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Specific inhibition of mTOR pathway induces anti-proliferative effect and decreases the hormone secretion in cultured pituitary adenoma cells. J Neurooncol 2015; 125:79-89. [DOI: 10.1007/s11060-015-1895-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 08/14/2015] [Indexed: 02/02/2023]
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59
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Nowak DG, Cho H, Herzka T, Watrud K, DeMarco DV, Wang VMY, Senturk S, Fellmann C, Ding D, Beinortas T, Kleinman D, Chen M, Sordella R, Wilkinson JE, Castillo-Martin M, Cordon-Cardo C, Robinson BD, Trotman LC. MYC Drives Pten/Trp53-Deficient Proliferation and Metastasis due to IL6 Secretion and AKT Suppression via PHLPP2. Cancer Discov 2015; 5:636-51. [PMID: 25829425 DOI: 10.1158/2159-8290.cd-14-1113] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/26/2015] [Indexed: 01/24/2023]
Abstract
UNLABELLED We have recently recapitulated metastasis of human PTEN/TP53-mutant prostate cancer in the mouse using the RapidCaP system. Surprisingly, we found that this metastasis is driven by MYC, and not AKT, activation. Here, we show that cell-cell communication by IL6 drives the AKT-MYC switch through activation of the AKT-suppressing phosphatase PHLPP2, when PTEN and p53 are lost together, but not separately. IL6 then communicates a downstream program of STAT3-mediated MYC activation, which drives cell proliferation. Similarly, in tissues, peak proliferation in Pten/Trp53-mutant primary and metastatic prostate cancer does not correlate with activated AKT, but with STAT3/MYC activation instead. Mechanistically, MYC strongly activates the AKT phosphatase PHLPP2 in primary cells and prostate cancer metastasis. We show genetically that Phlpp2 is essential for dictating the proliferation of MYC-mediated AKT suppression. Collectively, our data reveal competition between two proto-oncogenes, MYC and AKT, which ensnarls the Phlpp2 gene to facilitate MYC-driven prostate cancer metastasis after loss of Pten and Trp53. SIGNIFICANCE Our data identify IL6 detection as a potential causal biomarker for MYC-driven metastasis after loss of PTEN and p53. Second, our finding that MYC then must supersede AKT to drive cell proliferation points to MYC inhibition as a critical part of PI3K pathway therapy in lethal prostate cancer.
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Affiliation(s)
- Dawid G Nowak
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | - Hyejin Cho
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | - Tali Herzka
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | - Kaitlin Watrud
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | | | | | - Serif Senturk
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | | | - David Ding
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | | | - David Kleinman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | - Muhan Chen
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | | | - John E Wilkinson
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | | | - Carlos Cordon-Cardo
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Brian D Robinson
- Department of Pathology, NewYork-Presbyterian Hospital, Weill Cornell Medical College, New York, New York
| | - Lloyd C Trotman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York.
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60
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Li X, Gu S, Ling Y, Shen C, Cao X, Xie R. p53 inhibition provides a pivotal protective effect against ischemia-reperfusion injury in vitro via mTOR signaling. Brain Res 2015; 1605:31-8. [PMID: 25681550 DOI: 10.1016/j.brainres.2015.02.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 02/06/2023]
Abstract
Tumor suppressor p53 has recently been reported to have numerous functions independent of tumorigenesis, including neuronal survival during ischemia. The mammalian target of rapamycin (mTOR) signaling pathway plays a central role in the regulation of metabolism, cell growth, development, and cell survival. Our recent work has demonstrated the neuroprotective effects of the mTOR pathway. Considering that p53 is also an important regulator of mTOR, to further clarify the role of p53 and the mTOR signaling pathway in neuronal ischemic-reperfusion injury, we used mouse primary mixed cultured neurons with an oxygen glucose deprivation (OGD) model to mimic an ischemic-reperfusion injury in vitro. A lentiviral system was also used to inhibit or overexpress p53 to determine whether p53 alteration affects OGD and reperfusion injury. Our results show that activated p53 was induced and it suppressed mTOR expression in primary mixed cultured neurons after OGD and reperfusion. Inhibiting p53, using either a chemical inhibitor or lentiviral-mediated shRNA, exhibited neuroprotective effects in primary cultured neurons against OGD and reperfusion injury through the upregulation of mTOR activity. Such protective effects could be reversed by rapamycin, an mTOR inhibitor. Conversely, p53 overexpression tended to exacerbate the detrimental effects of OGD injury by downregulating mTOR activity. These results suggest that p53 inhibition has a pivotal protective effect against an in vitro ischemia-reperfusion injury via mTOR signaling and provides a potential and promising therapeutic target for stroke treatment.
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Affiliation(s)
- Xiaomu Li
- Department of Endocrinology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Shixin Gu
- Department of Neurosurgery, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China
| | - Yan Ling
- Department of Endocrinology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Chao Shen
- Department of Neurosurgery, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China
| | - Xiaoyun Cao
- Department of Neurosurgery, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China
| | - Rong Xie
- Department of Neurosurgery, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China.
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61
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Chi W, Meng F, Li Y, Li P, Wang G, Cheng H, Han S, Li J. Impact of microRNA-134 on neural cell survival against ischemic injury in primary cultured neuronal cells and mouse brain with ischemic stroke by targeting HSPA12B. Brain Res 2014; 1592:22-33. [DOI: 10.1016/j.brainres.2014.09.072] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 09/11/2014] [Accepted: 09/29/2014] [Indexed: 01/23/2023]
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62
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Tang H, Chen J, Fraidenburg DR, Song S, Sysol JR, Drennan AR, Offermanns S, Ye RD, Bonini MG, Minshall RD, Garcia JGN, Machado RF, Makino A, Yuan JXJ. Deficiency of Akt1, but not Akt2, attenuates the development of pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2014; 308:L208-20. [PMID: 25416384 DOI: 10.1152/ajplung.00242.2014] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Pulmonary vascular remodeling, mainly attributable to enhanced pulmonary arterial smooth muscle cell proliferation and migration, is a major cause for elevated pulmonary vascular resistance and pulmonary arterial pressure in patients with pulmonary hypertension. The signaling cascade through Akt, comprised of three isoforms (Akt1-3) with distinct but overlapping functions, is involved in regulating cell proliferation and migration. This study aims to investigate whether the Akt/mammalian target of rapamycin (mTOR) pathway, and particularly which Akt isoform, contributes to the development and progression of pulmonary vascular remodeling in hypoxia-induced pulmonary hypertension (HPH). Compared with the wild-type littermates, Akt1(-/-) mice were protected against the development and progression of chronic HPH, whereas Akt2(-/-) mice did not demonstrate any significant protection against the development of HPH. Furthermore, pulmonary vascular remodeling was significantly attenuated in the Akt1(-/-) mice, with no significant effect noted in the Akt2(-/-) mice after chronic exposure to normobaric hypoxia (10% O2). Overexpression of the upstream repressor of Akt signaling, phosphatase and tensin homolog deleted on chromosome 10 (PTEN), and conditional and inducible knockout of mTOR in smooth muscle cells were also shown to attenuate the rise in right ventricular systolic pressure and the development of right ventricular hypertrophy. In conclusion, Akt isoforms appear to have a unique function within the pulmonary vasculature, with the Akt1 isoform having a dominant role in pulmonary vascular remodeling associated with HPH. The PTEN/Akt1/mTOR signaling pathway will continue to be a critical area of study in the pathogenesis of pulmonary hypertension, and specific Akt isoforms may help specify therapeutic targets for the treatment of pulmonary hypertension.
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Affiliation(s)
- Haiyang Tang
- Department of Medicine, Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, Arizona; Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona; Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Jiwang Chen
- Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Dustin R Fraidenburg
- Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Shanshan Song
- Department of Medicine, Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, Arizona; Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona; Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Justin R Sysol
- Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois; Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois; and
| | - Abigail R Drennan
- Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Richard D Ye
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois; and
| | - Marcelo G Bonini
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois; and
| | - Richard D Minshall
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois; and
| | - Joe G N Garcia
- Department of Medicine, Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, Arizona
| | - Roberto F Machado
- Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Ayako Makino
- Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona
| | - Jason X-J Yuan
- Department of Medicine, Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, Arizona; Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona; Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois; Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois; and
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63
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Ratilal BO, Rocha JPF, Fernandes AMA, Arroja MMC, Barateiro AP, Brites DMTO, Pinto RMA, Sepodes BMN, Mota-Filipe HD. TDZD-8 pre-treatment in transient middle cerebral artery occlusion. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.biomag.2014.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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64
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Selvamani A, Williams MH, Miranda RC, Sohrabji F. Circulating miRNA profiles provide a biomarker for severity of stroke outcomes associated with age and sex in a rat model. Clin Sci (Lond) 2014; 127:77-89. [PMID: 24428837 PMCID: PMC4386587 DOI: 10.1042/cs20130565] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Small non-coding RNA [miRNA (microRNA)] found in the circulation have been used successfully as biomarkers and mechanistic targets for chronic and acute disease. The present study investigated the impact of age and sex on miRNA expression following ischaemic stroke in an animal model. Adult (6 month) and middle-aged (11-12 months) female and male rats were subject to MCAo (middle cerebral artery occlusion) using ET-1 (endothelin-1). Circulating miRNAs were analysed in blood samples at 2 and 5 days post-stroke, and brain miRNAs were analysed at 5 days post-stroke. Although stroke-associated infarction was observed in all groups, infarct volume and sensory-motor deficits were significantly reduced in adult females compared with middle-aged females, adult males or middle-aged males. At 2 days post-stroke, 21 circulating miRNAs were differentially regulated and PCA (principal component analysis) confirmed that most of the variance was due to age. At 5 days post-stroke, 78 circulating miRNAs exhibited significantly different regulation, and most of the variance was associated with sex. A small cohort (five) of miRNAs, miR-15a, miR-19b, miR-32 miR-136 and miR-199a-3p, were found to be highly expressed exclusively in adult females compared with middle-aged females, adult males and middle-aged males. Predicted gene targets for these five miRNAs analysed for KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways revealed that the top ten KEGG pathways were related to growth factor signalling, cell structure and PI3K (phosphoinositide 3-kinase)/Akt and mTOR (mammalian target of rapamycin) signalling. Overall, the pattern of circulating miRNA expression suggests an early influence of age in stroke pathology, with a later emergence of sex as a factor for stroke severity.
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Affiliation(s)
- Amutha Selvamani
- Women's Health in Neuroscience Program, Neuroscience and Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, U.S.A
| | - Madison H. Williams
- Women's Health in Neuroscience Program, Neuroscience and Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, U.S.A
| | - Rajesh C. Miranda
- Women's Health in Neuroscience Program, Neuroscience and Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, U.S.A
| | - Farida Sohrabji
- Women's Health in Neuroscience Program, Neuroscience and Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, U.S.A
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65
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Blood brain barrier and neuroinflammation are critical targets of IGF-1-mediated neuroprotection in stroke for middle-aged female rats. PLoS One 2014; 9:e91427. [PMID: 24618563 PMCID: PMC3949985 DOI: 10.1371/journal.pone.0091427] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 02/10/2014] [Indexed: 01/06/2023] Open
Abstract
Ischemia-induced cerebral infarction is more severe in older animals as compared to younger animals, and is associated with reduced availability of insulin-like growth factor (IGF)-1. This study determined the effect of post-stroke IGF-1 treatment, and used microRNA profiling to identify mechanisms underlying IGF-1’s neuroprotective actions. Post-stroke ICV administration of IGF-1 to middle-aged female rats reduced infarct volume by 39% when measured 24h later. MicroRNA analyses of ischemic tissue collected at the early post-stroke phase (4h) indicated that 8 out of 168 disease-related miRNA were significantly downregulated by IGF-1. KEGG pathway analysis implicated these miRNA in PI3K-Akt signaling, cell adhesion/ECM receptor pathways and T-and B-cell signaling. Specific components of these pathways were subsequently analyzed in vehicle and IGF-1 treated middle-aged females. Phospho-Akt was reduced by ischemia at 4h, but elevated by IGF-1 treatment at 24h. IGF-1 induced Akt activation was preceded by a reduction of blood brain barrier permeability at 4h post-stroke and global suppression of cytokines including IL-6, IL-10 and TNF-α. A subset of these cytokines including IL-6 was also suppressed by IGF-1 at 24h post-stroke. These data are the first to show that the temporal and mechanistic components of post-stroke IGF-1 treatment in older animals, and that cellular components of the blood brain barrier may serve as critical targets of IGF-1 in the aging brain.
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Xiong X, Xie R, Zhang H, Gu L, Xie W, Cheng M, Jian Z, Kovacina K, Zhao H. PRAS40 plays a pivotal role in protecting against stroke by linking the Akt and mTOR pathways. Neurobiol Dis 2014; 66:43-52. [PMID: 24583056 DOI: 10.1016/j.nbd.2014.02.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 01/08/2014] [Accepted: 02/19/2014] [Indexed: 11/16/2022] Open
Abstract
The proline-rich Akt substrate of 40kDa (PRAS40) protein is not only a substrate of the protein kinase Akt but also a component of the mTOR complex 1 (mTORC1), thus it links the Akt and the mTOR pathways. We investigated the potential protective role of PRAS40 in cerebral ischemia and its underlying mechanisms by using rats with lentiviral over-expression of PRAS40 and mice with PRAS40 gene knockout (PRAS40 KO). Our results show that gene transfer of PRAS40 reduced infarction size in rats by promoting phosphorylation of Akt, FKHR (FOXO1), PRAS40, and mTOR. In contrast, PRAS40 KO increased infarction size. Although the PRAS40 KO under normal condition did not alter baseline levels of phosphorylated proteins in the Akt and mTOR pathways, PRAS40 KO that underwent stroke exhibited reduced protein levels of p-S6K and p-S6 in the mTOR pathway but not p-Akt, or p-PTEN in the Akt pathway. Furthermore, co-immunoprecipitation suggests that there were less interactive effects between Akt and mTOR in the PRAS40 KO. In conclusion, PRAS40 appears to reduce brain injury by converting cell signaling from Akt to mTOR.
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Affiliation(s)
- Xiaoxing Xiong
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Rong Xie
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Hongfei Zhang
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Lijuan Gu
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Weiying Xie
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Michelle Cheng
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Zhihong Jian
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Kristina Kovacina
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Heng Zhao
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA.
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