Abstract 297: GJA1-20k Protects the Heart From Ischemic Injury by Inducing Mitochondrial Metabolic Quiescence

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Ying Fu ◽  
Wassim Basheer ◽  
Baiming Sun ◽  
Sosse Agvanian ◽  
Shaohua Xiao ◽  
...  
Keyword(s):  
Connexin 43 ◽  
Ischemic Injury ◽  
Full Length ◽  
Protein Isoforms ◽  
Control Group ◽  
Myocardial Infarct Size ◽  
Junction Protein ◽  
Alternative Translation

The mRNA of the GJA1 gene that encodes gap junction protein connexin 43 (Cx43) undergoes alternative translation, producing N-terminal truncated smaller protein isoforms. Unlike the well-characterized full-length Cx43 (GJA1-43k), little is known about the function and regulation of the smaller isoforms. Here, we report that global ischemia/reperfusion injury in Langendorff-perfused mouse hearts upregulates endogenous GJA1-20k, the most abundant isoform of alternative translation. Biochemical fractionation indicates that the induced GJA1-20k is preferentially enriched in cardiomyocyte mitochondria. When introduced in vitro through adenovirus-medicated gene expression, exogenous GJA1-20k, but not full length protein GJA1-43k, localizes to mitochondria and improves the survival and viability of adult cardiomyocytes when subjected to oxidative stress. In vivo gene transfer of GJA1-20k through retro-orbital injection of AAV9 virus results in lower mitochondria-dependent basal oxygen consumption as well as maximal respiratory capacity in cardiomyocytes, unlike GFP or GJA1-43k controls. Thus GJA1-20k, but not GJA1-43k, protects the heart against ischemic injury induced by permanent LAD ligation. As compared to GFP control group, myocardial infarct size in GJA1-20k treated hearts is reduced by 30% at 72 hours post LAD ligation. These results indicate that endogenous GJA1-20k is induced upon stress and has strong tropism to mitochondria. Increased GJA1-20k induces mitochondrial metabolic quiescence and affords cardioprotection in vitro and in vivo. Alternatively translated GJA1-20k acts as a novel mitochondrial stress protein and demonstrates therapeutic potential against ischemic injury.

scholarly journals Overexpression of SERCA2a Alleviates Cardiac Microvascular Ischemic Injury by Suppressing Mfn2-Mediated ER/Mitochondrial Calcium Tethering

2021 ◽  
Vol 9 ◽  
Author(s):  
Feng Tian ◽  
Ying Zhang
Keyword(s):  
Endoplasmic Reticulum ◽  
Infarct Size ◽  
Myocardial Infarct ◽  
Ischemic Injury ◽  
Calcium Overload ◽  
Mitochondrial Calcium ◽  
Myocardial Infarct Size ◽  
Hypoxic Injury

Our previous research has shown that type-2a Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) undergoes posttranscriptional oxidative modifications in cardiac microvascular endothelial cells (CMECs) in the context of excessive cardiac oxidative injury. However, whether SERCA2a inactivity induces cytosolic Ca2+ imbalance in mitochondrial homeostasis is far from clear. Mitofusin2 (Mfn2) is well known as an important protein involved in endoplasmic reticulum (ER)/mitochondrial Ca2+ tethering and the regulation of mitochondrial quality. Therefore, the aim of our study was to elucidate the specific mechanism of SERCA2a-mediated Ca2+ overload in the mitochondria via Mfn2 tethering and the survival rate of the heart under conditions of cardiac microvascular ischemic injury. In vitro, CMECs extracted from mice were subjected to 6 h of hypoxic injury to mimic ischemic heart injury. C57-WT and Mfn2KO mice were subjected to a 1 h ischemia procedure via ligation of the left anterior descending branch to establish an in vivo cardiac ischemic injury model. TTC staining, immunohistochemistry and echocardiography were used to assess the myocardial infarct size, microvascular damage, and heart function. In vitro, ischemic injury induced irreversible oxidative modification of SERCA2a, including sulfonylation at cysteine 674 and nitration at tyrosine 294/295, and inactivation of SERCA2a, which initiated calcium overload. In addition, ischemic injury-triggered [Ca2+]c overload and subsequent [Ca2+]m overload led to mPTP opening and ΔΨm dissipation compared with the control. Furthermore, ablation of Mfn2 alleviated SERCA2a-induced mitochondrial calcium overload and subsequent mito-apoptosis in the context of CMEC hypoxic injury. In vivo, compared with that in wild-type mice, the myocardial infarct size in Mfn2KO mice was significantly decreased. In addition, the findings revealed that Mfn2KO mice had better heart contractile function, decreased myocardial infarction indicators, and improved mitochondrial morphology. Taken together, the results of our study suggested that SERCA2a-dependent [Ca2+]c overload led to mitochondrial dysfunction and activation of Mfn2-mediated [Ca2+]m overload. Overexpression of SERCA2a or ablation of Mfn2 expression mitigated mitochondrial morphological and functional damage by modifying the SERCA2a/Ca2+-Mfn2 pathway. Overall, these pathways are promising therapeutic targets for acute cardiac microvascular ischemic injury.

scholarly journals Connexin 43 confers chemoresistance through activating PI3K

Oncogenesis ◽  
2022 ◽  
Vol 11 (1) ◽  
Author(s):  
Kevin J. Pridham ◽  
Farah Shah ◽  
Kasen R. Hutchings ◽  
Kevin L. Sheng ◽  
Sujuan Guo ◽  
...  
Keyword(s):  
Poor Prognosis ◽  
Connexin 43 ◽  
Therapeutic Potential ◽  
Mrna Levels ◽  
Phosphatidylinositol 3 Kinase ◽  
Junction Protein ◽  
Gap Junction Protein ◽  
Cx43 Mrna

AbstractCircumventing chemoresistance is crucial for effectively treating cancer including glioblastoma, a lethal brain cancer. The gap junction protein connexin 43 (Cx43) renders glioblastoma resistant to chemotherapy; however, targeting Cx43 is difficult because mechanisms underlying Cx43-mediated chemoresistance remain elusive. Here we report that Cx43, but not other connexins, is highly expressed in a subpopulation of glioblastoma and Cx43 mRNA levels strongly correlate with poor prognosis and chemoresistance in this population, making Cx43 the prime therapeutic target among all connexins. Depleting Cx43 or treating cells with αCT1–a Cx43 peptide inhibitor that sensitizes glioblastoma to the chemotherapy temozolomide–inactivates phosphatidylinositol-3 kinase (PI3K), whereas overexpression of Cx43 activates this signaling. Moreover, αCT1-induced chemo-sensitization is counteracted by a PI3K active mutant. Further research reveals that αCT1 inactivates PI3K without blocking the release of PI3K-activating molecules from membrane channels and that Cx43 selectively binds to the PI3K catalytic subunit β (PIK3CB, also called PI3Kβ or p110β), suggesting that Cx43 activates PIK3CB/p110β independent of its channel functions. To explore the therapeutic potential of simultaneously targeting Cx43 and PIK3CB/p110β, αCT1 is combined with TGX-221 or GSK2636771, two PIK3CB/p110β-selective inhibitors. These two different treatments synergistically inactivate PI3K and sensitize glioblastoma cells to temozolomide in vitro and in vivo. Our study has revealed novel mechanistic insights into Cx43/PI3K-mediated temozolomide resistance in glioblastoma and demonstrated that targeting Cx43 and PIK3CB/p110β together is an effective therapeutic approach for overcoming chemoresistance.

scholarly journals Neuroprotective Effects of Ginsenosides against Cerebral Ischemia

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1102 ◽  
Author(s):  
Zhekang Cheng ◽  
Meng Zhang ◽  
Chengli Ling ◽  
Ying Zhu ◽  
Hongwei Ren ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Ischemic Injury ◽  
Neurological Dysfunction ◽  
Control Group ◽  
Protective Effects ◽  
Ginsenoside Rb1 ◽  
Neuroprotective Effects

Ginseng has been used worldwide as traditional medicine for thousands of years, and ginsenosides have been proved to be the main active components for their various pharmacological activities. Based on their structures, ginsenosides can be divided into ginseng diol-type A and ginseng triol-type B with different pharmacological effects. In this study, six ginsenosides, namely ginsenoside Rb1, Rh2, Rg3, Rg5 as diol-type ginseng saponins, and Rg1 and Re as triol-type ginseng saponins, which were reported to be effective for ischemia-reperfusion (I/R) treatment, were chosen to compare their protective effects on cerebral I/R injury, and their mechanisms were studied by in vitro and in vivo experiments. It was found that all ginsenosides could reduce reactive oxygen species (ROS), inhibit apoptosis and increase mitochondrial membrane potential in cobalt chloride-induced (CoCl2-induced) PC12 cells injury model, and they could reduce cerebral infarction volume, brain neurological dysfunction of I/R rats in vivo. The results of immunohistochemistry and western blot showed that the expression of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), silencing information regulator (SIRT1) and nuclear transcription factor P65 (NF-κB) in hippocampal CA1 region of some ginsenoside groups were also reduced. In general, the effect on cerebral ischemia of Rb1 and Rg3 was significantly improved compared with the control group, and was the strongest among all the ginsenosides. The effect on SIRT1 activation of ginsenoside Rb1 and the inhibition effect of TLR4/MyD88 protein expression of ginsenoside Rb1 and Rg3 were significantly stronger than that of other groups. The results indicated that ginsenoside Rg1, Rb1, Rh2, Rg3, Rg5 and Re were effective in protecting the brain against ischemic injury, and ginsenoside Rb1 and Rg3 have the strongest therapeutic activities in all the tested ginsenosides. Their neuroprotective mechanism is associated with TLR4/MyD88 and SIRT1 activation signaling pathways, and they can reduce cerebral ischemic injury by inhibiting NF-κB transcriptional activity and the expression of proinflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6).

scholarly journals Expression profile and subcellular localization of Torque teno sus virus proteins

2011 ◽  
Vol 92 (10) ◽  
pp. 2446-2457 ◽  
Author(s):  
Laura Martínez-Guinó ◽  
Maria Ballester ◽  
Joaquim Segalés ◽  
Tuija Kekarainen
Keyword(s):  
Subcellular Localization ◽  
Splice Variants ◽  
Full Length ◽  
Protein Isoforms ◽  
Kidney Cells ◽  
Porcine Kidney ◽  
New Information ◽  
Torque Teno Sus Virus

In the present study, the expression, generation and subcellular localization of Torque teno sus virus (TTSuV) proteins were characterized into two genetically distinct TTSuV species (TTSuV1 and TTSuV2). Following transfection of three TTSuV1 and TTSuV2 full-length ORF (ORF1, ORF2 and ORF3) expression constructs into porcine kidney cells, alternative splice variants encoding new TTSuV protein isoforms were identified for the first time. Proteins encoded from ORF1 and ORF3 were localized in the nucleoli of porcine kidney cells and that of ORF2 in the cytoplasm and nucleus excluding the nucleoli. The subcellular localization of the different protein isoforms was not only similar between distinct TTSuV species but also to the ones described in human Torque teno virus (TTV). Results of the present in vitro study were not based on full-length viral clones but suggested that alternative splicing strategy to generate TTSuV protein isoforms probably occurs in vivo. Obtained data provide new information on molecular biology of TTSuV and anelloviruses, which until now has been solely based on results obtained from human TTV.

scholarly journals Human endometrium-derived stem cell improves cardiac function after myocardial ischemic injury by enhancing angiogenesis and myocardial metabolism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuemei Fan ◽  
Sheng He ◽  
Huifang Song ◽  
Wenjuan Yin ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cardiac Function ◽  
Premenopausal Women ◽  
Ischemic Injury ◽  
Cardiac Repair ◽  
Human Endometrium ◽  
Control Group ◽  
Fdg Uptake

Abstract Background The human endometrium in premenopausal women is an active site of physiological angiogenesis, with regenerative cells present, suggesting that the endometrium contains adult angiogenic stem cells. In the context of cardiac repair after ischemic injury, angiogenesis is a crucial process to rescue cardiomyocytes. We therefore investigated whether human endometrium-derived stem cells (hEMSCs) can be used for cardiac repair after ischemic injury and their possible underlying mechanisms. Methods Comparisons were made between hEMSCs successfully isolated from 22 premenopausal women and human bone marrow mesenchymal stem cells (hBMSCs) derived from 25 age-matched patients. Cell proliferation, migration, differentiation, and angiogenesis were evaluated through in vitro experiments, while the ability of hEMSCs to restore cardiac function was examined by in vivo cell transplantation into the infarcted nude rat hearts. Results In vitro data showed that hEMSCs had greater proliferative and migratory capacities, whereas hBMSCs had better adipogenic differentiation ability. Human umbilical cord vein endothelial cells, treated with conditioned medium from hEMSCs, had significantly higher tube formation than that from hBMSCs or control medium, indicating greater angiogenic potentials for hEMSCs. In vivo, hEMSC transplantation preserved cardiac function, decreased infarct size, and improved tissue repair post-injury. Cardiac metabolism, assessed by 18F-FDG uptake, showed that 18F-FDG uptake at the infarction area was significantly higher in both hBMSC and hEMSC groups, compared to the PBS control group, with hEMSCs having the highest uptake, suggesting hEMSC treatment improves cardiomyocyte metabolism and survival after injury. Mechanistic assessment of the angiogenic potential for hEMSCS revealed that angiogenesis-related factors angiopoietin 2, Fms-like tyrosine kinase 1, and FGF9 were significantly upregulated in hEMSC-implanted infarcted hearts, compared to the PBS control group. Conclusion hEMSCs, compared to hBMSCs, have greater capacity to induce angiogenesis, and improved cardiac function after ischemic injury.

scholarly journals Cell type specific profiling of alternative translation identifies novel protein isoforms in the mouse brain

2018 ◽  
Author(s):  
Darshan Sapkota ◽  
Allison M. Lake ◽  
Wei Yang ◽  
Chengran Yang ◽  
Hendrik Wesseling ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Stop Codon ◽  
Affinity Purification ◽  
Protein Isoforms ◽  
Cell Type ◽  
Alternative Translation ◽  
Cell Type Specific ◽  
Ribosome Footprinting

AbstractTranslation canonically begins at a single AUG and terminates at the stop codon, generating one protein species per transcript. However, some transcripts may use alternative initiation sites or sustain translation past their stop codon, generating multiple protein isoforms. Through other mechanisms such as alternative splicing, both neurons and glia exhibit remarkable transcriptional diversity, and these other forms of post-transcriptional regulation are impacted by neural activity and disease. Here, using ribosome footprinting, we demonstrate that alternative translation is likewise abundant in the central nervous system and modulated by stimulation and disease. First, in neuron/glia mixed cultures we identify hundreds of transcripts with alternative initiation sites and confirm the protein isoforms corresponding to a subset of these sites by mass spectrometry. Many of them modulate their alternative initiation in response to KCl stimulation, indicating activity-dependent regulation of this phenomenon. Next, we detect several transcripts undergoing stop codon readthrough thus generating novel C-terminally-extended protein isoforms in vitro. Further, by coupling Translating Ribosome Affinity Purification to ribosome footprinting to enable cell-type specific analysis in vivo, we find that several of both neuronal and astrocytic transcripts undergo readthrough in the mouse brain. Functional analyses of one of these transcripts, Aqp4, reveals readthrough confers perivascular localization, indicating readthrough can be a conserved mechanism to modulate protein function. Finally, we show that AQP4 readthrough is disrupted in multiple gliotic disease models. Our study demonstrates the extensive and regulated use of alternative translational events in the brain and indicates that some of these events alter key protein properties.

scholarly journals Connexin 43 confers chemoresistance through activating PI3K

2020 ◽  
Author(s):  
Kevin J Pridham ◽  
Farah Shah ◽  
Kevin L Sheng ◽  
Sujuan Guo ◽  
Min Liu ◽  
...  
Keyword(s):  
Connexin 43 ◽  
Carboxyl Terminus ◽  
Phosphatidylinositol 3 Kinase ◽  
Poor Patient ◽  
Junction Protein ◽  
Gap Junction Protein ◽  
Targeting Peptide ◽  
Patient Prognosis

ABSTRACTCircumventing chemoresistance is crucial for effectively treating glioblastoma due to limited therapeutic options. The gap junction protein connexin 43 (Cx43) renders glioblastoma resistant to the frontline chemotherapy temozolomide; however, targeting Cx43 is difficult because mechanisms underlying Cx43-mediated chemoresistance remain elusive. Here we show that Cx43, but not other connexins, is highly expressed in glioblastoma and strongly correlates with poor patient prognosis and chemoresistance, making Cx43 the prime therapeutic target among all connexins. The intracellular carboxyl terminus of Cx43 binds to phosphatidylinositol 3-kinase (PI3K) catalytic subunit β (PIK3CB, also called PI3Kβ or p110β), thereby activating PI3K signaling independent of Cx43-channels and subsequently inducing temozolomide resistance. A combination of αCT1, a Cx43-targeting peptide inhibitor, and PIK3CB-selective inhibitors restores temozolomide sensitivity in vitro and in vivo. This study not only reveals novel mechanistic insights into chemoresistance in glioblastoma, but also demonstrates that targeting Cx43 and PIK3CB/p110β is an effective approach for overcoming chemoresistance.

In-vitro- und In-vivo-Wirkung von Schilddrüsenhormon auf das Wachstum von Neuroblastomzellen

1990 ◽  
Vol 29 (03) ◽  
pp. 120-124
Author(s):  
R. P. Baum ◽  
E. Rohrbach ◽  
G. Hör ◽  
B. Kornhuber ◽  
E. Busse
Keyword(s):  
Cell Differentiation ◽  
Neuroblastoma Cells ◽  
Control Group ◽  
Initial Value ◽  
Initial Rise ◽  
Biphasic Effect ◽  
Contrast Microscopy ◽  
Morphological Sign

The effect of triiodothyronine (T3) on the differentiation of cultured neuroblastoma (NB) cells was studied after 9 days of treatment with a dose of 10-4 M/106 cells per day. Using phase contrast microscopy, 30-50% of NB cells showed formation of neurites as a morphological sign of cellular differentiation. The initial rise of the mitosis rate was followed by a plateau. Changes in cyclic nucleotide content, in the triphosphates and in the activity of the enzyme ornithine decarboxylase (ODC) were assessed in 2 human and 2 murine cell lines to serve as biochemical parameters of the cell differentiation induced by T3. Whereas the cAMP level increased significantly (3 to 7 fold compared with its initial value), the cGMP value dropped to 30 to 50% of that of the control group. ATP and GTP increased about 200%, the ODC showed a decrease of about 50%. The present studies show a biphasic effect of T3 on neuroblastoma cells: the initial rise of mitotic activity is followed by increased cell differentiation starting from day 4 of the treatment.

Protective Effect of Boswellic Resin Against Memory Loss and Alzheimer’s Induced by Aluminum Tetrachloride and D-Galactose (Experimental study in Mice)

2020 ◽  
Author(s):  
K. Zerrouki ◽  
N. Djebli ◽  
L. Gadouche ◽  
I. Erdogan Orhan ◽  
F. SezerSenol Deniz ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Protective Effect ◽  
Cell Damage ◽  
Memory Loss ◽  
Control Group ◽  
Total Extract ◽  
Swiss Mice ◽  
Octyl Acetate

Nowadays, because of the industrialization, a lot of contaminant were available ; the consequences of this availability are apparition of diseases including neurodegeneration. Neurodegenerative diseases of the human brain comprise a variety of disorders that affect an increasing percentage of the population. This study is based on the effect of the Boswellic resin, which is from a medicinal plant and known for its antioxidant effects on nerve cell damage. The objective of this work was to evaluate the in vitro and in vivo effects of the Boswellic resin on anticholinesterase activity and Alzheimer’s disease (AD) induced by D-galactose and aluminum tetrachloride in Swiss mice. Chemical composition of the resin essential oil was identified by the CG-MS analysis. The antioxidant activity was also assessed by the DMPD and metal chelation methods. In order to understand the mechanism of memory improvement, the acetylcholinesterase, AChE, and butyrylcholinesterase, BChE, inhibitory assays were performed. In vivo part of the study was achieved on Swiss mice divided into four groups: control, AD model, treated AD, and treated control group. The identification of chemical composition by CG-MS reach the 89.67% of the total extract compounds presented some very important molecules (p-Cymene, n-Octyl acetate, α-Pinene…). The present study proves that Boswellic resin improves memory and learning in treated Alzheimer’s group, modulates the oxidative stress and be involved in the protective effect against amyloid deposition and neurodegeneration, and stimulates the immune system in mice’s brain.

Sign in / Sign up

Export Citation Format

Share Document