β-Adrenergic Receptor Mediated Protection against Doxorubicin-Induced Apoptosis in Cardiomyocytes: The Impact of High Ambient Glucose

Recent studies have demonstrated that the β2-adrenergic receptor (β2AR)-Gαi signaling pathway exerts a cardiac antiapoptotic effect. The goals of this study were to determine the intracellular signaling factors involved in β2AR-mediated protection against doxorubicin-induced apoptosis in H9c2 cardiomyocyte and explore the impact of high ambient glucose on the antiapoptotic effect. Under physiological glucose environment (100 mg/dl), β2AR stimulation prevented doxorubicin-induced apoptosis, which was attenuated by cotreatment with wortmannin, a phosphoinositide 3-kinase (PI3K) inhibitor, or transfection of a dominant-negative Akt. Inhibition of Src kinase with 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d] pyrimidine or cSrc small interfering RNA 32 also attenuated the antiapoptotic effect. Inhibition of platelet-derived growth factor receptor (PDGFR) with AG1296 reversed the β2AR-induced antiapoptotic effect. Transfection of an active Src cDNA (Y529F) alone was sufficient to render the cells resistant to apoptosis, and the resistance was blocked by wortmannin. Transfection of an active PI3K minigene (iSH2-p110) alone also induced resistance to apoptosis, and the resistance was reversed by an Akt-inhibitor but not by AG1296. High ambient glucose (450 mg/dl) caused two major effects: 1) it significantly reduced βAR-induced PDGFR phosphorylation, Src kinase activity, and activation of PI3K signaling pathway; and 2) it partially attenuated β2AR-induced antiapoptotic effect. These data provide in vitro evidence supporting a signaling cascade by which β2AR exerts a protective effect against doxorubicin-induced apoptosis via sequential involvement of Gαi, Gβγ, Src, PDGFR, PI3K, and Akt. High ambient glucose significantly attenuates β2AR-mediated cardioprotection by suppressing factors involved in this cascade including PDGFR, Src, and PI3K/Akt.

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Akt Inhibitor Akt-IV Blocks Virus Replication through an Akt-Independent Mechanism

Journal of Virology ◽

10.1128/jvi.01092-09 ◽

2009 ◽

Vol 83 (22) ◽

pp. 11665-11672 ◽

Cited By ~ 21

Author(s):

Ewan F. Dunn ◽

Rachel Fearns ◽

John H. Connor

Keyword(s):

Signaling Pathway ◽

Virus Replication ◽

Intracellular Signaling ◽

Akt Pathway ◽

Akt Inhibitor ◽

Antiviral Compound ◽

Intracellular Signaling Pathway ◽

Cytopathic Effects ◽

Syncytial Virus

ABSTRACT Many viruses activate the phosphatidylinositol 3′-kinase (PI3k)/Akt intracellular signaling pathway to promote viral replication. We have analyzed whether a rapidly replicating rhabdovirus, vesicular stomatitis virus (VSV), requires the PI3k/Akt signaling pathway for its replication. Through the use of chemical inhibitors of PI3k and Akt, we show that VSV replication and cytopathic effects do not require activation of these kinases. Inhibitors that block the activating phosphorylations of Akt at threonine 308 (Thr308) and serine 473 (Ser473) did not inhibit VSV protein expression or the induction of the cytopathic effects of VSV. One compound, Akt inhibitor Akt-IV, inhibited the replication of VSV, respiratory syncytial virus, and vaccinia virus but increased the phosphorylation of Akt at positions Thr308 and Ser473 and did not inhibit Akt kinase activity in vitro. Together, our data suggest that the PI3k/Akt pathway is of limited relevance to the replication of VSV but that Akt inhibitor Akt-IV is a novel broad-spectrum antiviral compound with a mechanism differing from that of its previously reported effect on the PI3k/Akt pathway. Identification of other targets for this compound may define a new approach for blocking virus replication.

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Dexamethasone Induces Apoptosis in Proliferative Chondrocytes through Activation of Caspases and Suppression of the Akt-Phosphatidylinositol 3′-Kinase Signaling Pathway

Endocrinology ◽

10.1210/en.2004-1152 ◽

2005 ◽

Vol 146 (3) ◽

pp. 1391-1397 ◽

Cited By ~ 92

Author(s):

Dionisios Chrysis ◽

Farasat Zaman ◽

Andrei S. Chagin ◽

Masaharu Takigawa ◽

Lars Sävendahl

Keyword(s):

Signaling Pathway ◽

Pi3k Pathway ◽

Caspase 8 ◽

Phosphatidylinositol 3 Kinase ◽

Akt Inhibitor ◽

Growth Plate Chondrocytes ◽

Igf I ◽

Induced Apoptosis ◽

Phosphatidylinositol 3

Although glucocorticoids are known to induce apoptosis in chondrocytes, the mechanisms for this effect and the potential antiapoptotic role of IGF-I are unknown. To address this, we studied the effects of dexamethasone (Dexa) on apoptosis in the HCS-2/8 chondrocytic cell line. Dexa (25 μm) increased apoptosis (cell death ELISA) by 39% and 45% after 48 and 72 h, respectively (P < 0.01 and P < 0.05, respectively). IGF-I (100 ng/ml) decreased Dexa-induced apoptosis to levels similar to control cells. Apoptosis was associated with cleavage of poly-ADP-ribose polymerase (PARP) and α-fodrin and activation of caspases-8, -9, and -3 (Western), an effect that was counteracted when chondrocytes were cocultured with Dexa + IGF-I. Inhibitors for caspases-8, -9, and -3 (50 μm each) equally suppressed Dexa-induced apoptosis (P < 0.01). Time-response experiments showed that caspase-8 was activated earlier (at 12 h) than caspase-9 (at 36 h). We studied the phosphatidylinositol 3′-kinase (PI3K) pathway to further investigate the mechanisms of Dexa-induced apoptosis. Dexa decreased Akt phosphorylation by 93% (P < 0.001) without affecting total Akt and increased the p85α subunit 4-fold. The Akt inhibitor SH-6 (10 μm) increased apoptosis by 54% (P < 0.001). When combining Dexa with SH-6, apoptosis was not further increased, showing that Dexa-induced apoptosis is mediated through inhibition of the PI3K pathway. Addition of IGF-I to SH-6- or Dexa + SH-6-treated cells decreased apoptosis by 21.2% (P < 0.001) and 20.6% (P < 0.001), respectively. We conclude that Dexa-induced apoptosis is caspase dependent with an early activation of caspase-8. IGF-I can rescue chondrocytes from Dexa-induced apoptosis partially through the activation of other pathways than the PI3K signaling pathway. Based on our in vitro data, we speculate that in vivo treatment with glucocorticoids may diminish longitudinal growth by increasing apoptosis of proliferative growth plate chondrocytes.

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VDAC1 Mediated Anticancer Activity of Gallic Acid in Human Lung Adenocarcinoma A549 Cells

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520617666170912115441 ◽

2018 ◽

Vol 18 (2) ◽

pp. 255-262 ◽

Cited By ~ 5

Author(s):

Aikebaier Maimaiti ◽

Amier Aili ◽

Hureshitanmu Kuerban ◽

Xuejun Li

Keyword(s):

Western Blot ◽

Cell Viability ◽

Gallic Acid ◽

Molecular Mechanisms ◽

A549 Cells ◽

Dependent Manner ◽

Lung Carcinoma Cells ◽

Induced Apoptosis ◽

The Impact

Aims: Gallic acid (GA) is generally distributed in a variety of plants and foods, and possesses cell growth-inhibiting activities in cancer cell lines. In the present study, the impact of GA on cell viability, apoptosis induction and possible molecular mechanisms in cultured A549 lung carcinoma cells was investigated. Methods: In vitro experiments showed that treating A549 cells with various concentrations of GA inhibited cell viability and induced apoptosis in a dose-dependent manner. In order to understand the mechanism by which GA inhibits cell viability, comparative proteomic analysis was applied. The changed proteins were identified by Western blot and siRNA methods. Results: Two-dimensional electrophoresis revealed changes that occurred to the cells when treated with or without GA. Four up-regulated protein spots were clearly identified as malate dehydrogenase (MDH), voltagedependent, anion-selective channel protein 1(VDAC1), calreticulin (CRT) and brain acid soluble protein 1(BASP1). VDAC1 in A549 cells was reconfirmed by western blot. Transfection with VDAC1 siRNA significantly increased cell viability after the treatment of GA. Further investigation showed that GA down regulated PI3K/Akt signaling pathways. These data strongly suggest that up-regulation of VDAC1 by GA may play an important role in GA-induced, inhibitory effects on A549 cell viability.

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Isorhynchophylline Protects PC12 Cells Against Beta-Amyloid-Induced Apoptosis via PI3K/Akt Signaling Pathway

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2013/163057 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 19

Author(s):

Yan-Fang Xian ◽

Zhi-Xiu Lin ◽

Qing-Qiu Mao ◽

Jian-Nan Chen ◽

Zi-Ren Su ◽

...

Keyword(s):

Signaling Pathway ◽

Pc12 Cells ◽

Molecular Mechanisms ◽

Glycogen Synthase ◽

Neuroprotective Effect ◽

Protective Action ◽

Protective Effects ◽

Phosphorylated Akt ◽

Induced Apoptosis

The neurotoxicity of amyloid-β(Aβ) has been implicated as a critical cause of Alzheimer’s disease. Isorhynchophylline (IRN), an oxindole alkaloid isolated fromUncaria rhynchophylla,exerts neuroprotective effect againstAβ25–35-induced neurotoxicityin vitro. However, the exact mechanism for its neuroprotective effect is not well understood. The present study aimed to investigate the molecular mechanisms underlying the protective action of IRN againstAβ25–35-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. Pretreatment with IRN significantly increased the cell viability, inhibited the release of lactate dehydrogenase and the extent of DNA fragmentation inAβ25–35-treated cells. IRN treatment was able to enhance the protein levels of phosphorylated Akt (p-Akt) and glycogen synthase kinase-3β(p-GSK-3β). Lithium chloride blockedAβ25–35-induced cellular apoptosis in a similar manner as IRN, suggesting that GSK-3βinhibition was involved in neuroprotective action of IRN. Pretreatment with LY294002 completely abolished the protective effects of IRN. Furthermore, IRN reversedAβ25–35-induced attenuation in the level of phosphorylated cyclic AMP response element binding protein (p-CREB) and the effect of IRN could be blocked by the PI3K inhibitor. These experimental findings unambiguously suggested that the protective effect of IRN againstAβ25–35-induced apoptosis in PC12 cells was associated with the enhancement of p-CREB expression via PI3K/Akt/GSK-3βsignaling pathway.

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Macamide B Pretreatment Attenuates Neonatal Hypoxic-Ischemic Brain Damage of Mice Induced Apoptosis by Regulates Autophagy Via The PI3K/AKT Signaling Pathway

10.21203/rs.3.rs-952715/v1 ◽

2021 ◽

Author(s):

Xiaoxia Yang ◽

Mengxia Wang ◽

Qian Zhou ◽

Yanxian Bai ◽

Jing Liu ◽

...

Keyword(s):

Signaling Pathway ◽

Brain Damage ◽

Infarct Volume ◽

Neuroprotective Effect ◽

Akt Signaling ◽

Akt Signaling Pathway ◽

Ischemic Brain Damage ◽

Ischemic Brain ◽

Induced Apoptosis ◽

The Impact

Abstract Lepidium meyenii (Maca) is an annual or biennial herb from South America that is a member of the genus Lepidium L. in the family Cruciferae. This herb has antioxidant, anti-apoptotic, and enhances autophagy functions and can prevent cell death, and protect neurons from ischemic damage. Macamide B, an effective active ingredient of maca, has a neuroprotective role in neonatal hypoxic-ischemic brain damage (HIBD), and the underlying mechanism of its neuroprotective effect is not yet known. The purpose of this study is to explore the impact of macamide B on HIBD-induced autophagy and apoptosis and its potential mechanism for neuroprotection. The modified Rice-Vannucci method was used to induce HIBD on 7-day-old (P7) macamide B and vehicle-pretreated pups. TTC staining was used to evaluate the cerebral infarct volume of pups, brain water content was measured to evaluate the neurological function of pups, neurobehavioral testing was used to assess functional recovery after HIBD, TUNEL and FJC staining was used to detect cell autophagy and apoptosis, and western blot analysis was used to detect the expression levels of the pro-survival signaling pathway phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and autophagy and the apoptosis-related proteins. The results show that macamide B pretreatment can significantly decrease brain damage, improve the recovery of neural function after HIBD. At the same time, macamide B pretreatment can induce the activation of PI3K/AKT signaling pathway after HIBD, enhance autophagy, and reduce hypoxic-ischemic (HI)-induced apoptosis. In addition, 3-methyladenine (3-MA), an inhibitor of PI3K/AKT signaling pathway, significantly inhibits the increase in autophagy levels, aggravates HI-induced apoptosis, and reverses the neuroprotective effect of macamide B on HIBD. Our data indicate that macamide B pretreatment might regulate autophagy through PI3K/AKT signaling pathway, thereby reducing HIBD-induced apoptosis and exerting neuroprotective effects on neonatal HIBD. Macamide B may become a new drug for the prevention and treatment of HIBD.

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Mouse Receptor Interacting Protein 3 Does Not Contain a Caspase-Recruiting or a Death Domain but Induces Apoptosis and Activates NF-κB

Molecular and Cellular Biology ◽

10.1128/mcb.19.10.6500 ◽

1999 ◽

Vol 19 (10) ◽

pp. 6500-6508 ◽

Cited By ~ 39

Author(s):

Nanette J. Pazdernik ◽

David B. Donner ◽

Mark G. Goebl ◽

Maureen A. Harrington

Keyword(s):

Sequence Similarity ◽

Kinase Domain ◽

Dominant Negative ◽

Dominant Negative Mutant ◽

Death Domain ◽

Interacting Protein ◽

C Terminus ◽

Catalytically Active ◽

Induced Apoptosis

ABSTRACT The death domain-containing receptor superfamily and their respective downstream mediators control whether or not cells initiate apoptosis or activate NF-κB, events critical for proper immune system function. A screen for upstream activators of NF-κB identified a novel serine-threonine kinase capable of activating NF-κB and inducing apoptosis. Based upon domain organization and sequence similarity, this novel kinase, named mRIP3 (mouse receptor interacting protein 3), appears to be a new RIP family member. RIP, RIP2, and mRIP3 contain an N-terminal kinase domain that share 30 to 40% homology. In contrast to the C-terminal death domain found in RIP or the C-terminal caspase-recruiting domain found in RIP2, the C-terminal tail of mRIP3 contains neither motif and is unique. Despite this feature, overexpression of the mRIP3 C terminus is sufficient to induce apoptosis, suggesting that mRIP3 uses a novel mechanism to induce death. mRIP3 also induced NF-κB activity which was inhibited by overexpression of either dominant-negative NIK or dominant-negative TRAF2. In vitro kinase assays demonstrate that mRIP3 is catalytically active and has autophosphorylation site(s) in the C-terminal domain, but the mRIP3 catalytic activity is not required for mRIP3 induced apoptosis and NF-κB activation. Unlike RIP and RIP2, mRIP3 mRNA is expressed in a subset of adult tissues and is thus likely to be a tissue-specific regulator of apoptosis and NF-κB activity. While the lack of a dominant-negative mutant precludes linking mRIP3 to a known upstream regulator, characterizing the expression pattern and the in vitro functions of mRIP3 provides insight into the mechanism(s) by which cells modulate the balance between survival and death in a cell-type-specific manner.

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GSK-3 is an RNA polymerase II phospho-CTD kinase

Nucleic Acids Research ◽

10.1093/nar/gkaa322 ◽

2020 ◽

Vol 48 (11) ◽

pp. 6068-6080 ◽

Cited By ~ 1

Author(s):

Nicolás Nieto Moreno ◽

Florencia Villafañez ◽

Luciana E Giono ◽

Carmen Cuenca ◽

Gastón Soria ◽

...

Keyword(s):

Dna Damage ◽

Rna Polymerase ◽

Rna Polymerase Ii ◽

Glycogen Synthase ◽

Dominant Negative ◽

Dominant Negative Mutant ◽

Transcriptional Elongation ◽

Induced Apoptosis ◽

Carboxy Terminal

Abstract We have previously found that UV-induced DNA damage causes hyperphosphorylation of the carboxy terminal domain (CTD) of RNA polymerase II (RNAPII), inhibition of transcriptional elongation and changes in alternative splicing (AS) due to kinetic coupling between transcription and splicing. In an unbiased search for protein kinases involved in the AS response to DNA damage, we have identified glycogen synthase kinase 3 (GSK-3) as an unforeseen participant. Unlike Cdk9 inhibition, GSK-3 inhibition only prevents CTD hyperphosphorylation triggered by UV but not basal phosphorylation. This effect is not due to differential degradation of the phospho-CTD isoforms and can be reproduced, at the AS level, by overexpression of a kinase-dead GSK-3 dominant negative mutant. GSK-3 inhibition abrogates both the reduction in RNAPII elongation and changes in AS elicited by UV. We show that GSK-3 phosphorylates the CTD in vitro, but preferentially when the substrate is previously phosphorylated, consistently with the requirement of a priming phosphorylation reported for GSK-3 efficacy. In line with a role for GSK-3 in the response to DNA damage, GSK-3 inhibition prevents UV-induced apoptosis. In summary, we uncover a novel role for a widely studied kinase in key steps of eukaryotic transcription and pre-mRNA processing.

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Targeting neuropilin-1 suppresses the stability of CD4+CD25+ regulatory T cells via the NF-κB signaling pathway in sepsis

Infection and Immunity ◽

10.1128/iai.00399-20 ◽

2020 ◽

Author(s):

Yu-lei Gao ◽

Chun-xue Wang ◽

Zi-yi Wang ◽

Wen-jie Li ◽

Yan-cun Liu ◽

...

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Signaling Pathway ◽

Binding Activity ◽

Dna Binding Activity ◽

Sepsis Model ◽

The Stability ◽

The Impact ◽

Tgf Β1

Neuropilin (Nrp)-1 contributes to maintain the stability of CD4+CD25+ regulatory T cells (Tregs). We investigated the impact of Nrp-1 on the stability of CD4+CD25+ Tregs, and the underlying signaling pathways, in a sepsis model. Splenic CD4+CD25+ Tregs were treated with anti-Nrp-1, or transfected to silence Nrp-1 and ikkβ, or administered with PDTC, followed by rSema3A in sepsis simulation. After creation of a sepsis model in mice, anti-Nrp-1 was administered. Expression of foxp3- TSDR, apoptosis rate, Foxp-3/CTLA-4/TGF-β1, IL-10 and TGF-β1, and NF-κB signaling activity of CD4+CD25+ Tregs were determined. Sepsis simulation with or without rSema3A increased the stability of CD4+CD25+ Tregs, including an increase in the expression of Foxp-3/CTLA-4/TGF-β1, decrease in apoptosis and methylation of foxp3- TSDR, increase in the secretion of TGF-β1 and IL-10, and increase in the immunosuppressive effect on CD4+T lymphocytes. silencing of Nrp-1 or anti-Nrp-1 treatment interdicted LPS stimulation with or without a rSema3A-mediated effect. Sepsis simulation increased the DNA-binding activity of NF-κB, as well as the p-ikkβ/ikkβ and p-P65/P65 ratios in vitro and vivo. Silencing of ikkβ expression or PDTC treatment suppressed the stability of CD4+CD25+ Tregs in LPS-induced sepsis. Weakening Nrp-1 reduced the stability of CD4+CD25+ Tregs by regulating the NF-κB signaling pathway, and could be a new target for immunoregulation in sepsis.

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Sensing through Non-Sensing Ocular Ion Channels

International Journal of Molecular Sciences ◽

10.3390/ijms21186925 ◽

2020 ◽

Vol 21 (18) ◽

pp. 6925

Author(s):

Meha Kabra ◽

Bikash Ranjan Pattnaik

Keyword(s):

Ion Channels ◽

Visual Processing ◽

Signal Transmission ◽

Dominant Negative ◽

Dominant Negative Effect ◽

Cone Dystrophy ◽

Wide Range ◽

The Impact

Ion channels are membrane-spanning integral proteins expressed in multiple organs, including the eye. In the eye, ion channels are involved in various physiological processes, like signal transmission and visual processing. A wide range of mutations have been reported in the corresponding genes and their interacting subunit coding genes, which contribute significantly to an array of blindness, termed ocular channelopathies. These mutations result in either a loss- or gain-of channel functions affecting the structure, assembly, trafficking, and localization of channel proteins. A dominant-negative effect is caused in a few channels formed by the assembly of several subunits that exist as homo- or heteromeric proteins. Here, we review the role of different mutations in switching a “sensing” ion channel to “non-sensing,” leading to ocular channelopathies like Leber’s congenital amaurosis 16 (LCA16), cone dystrophy, congenital stationary night blindness (CSNB), achromatopsia, bestrophinopathies, retinitis pigmentosa, etc. We also discuss the various in vitro and in vivo disease models available to investigate the impact of mutations on channel properties, to dissect the disease mechanism, and understand the pathophysiology. Innovating the potential pharmacological and therapeutic approaches and their efficient delivery to the eye for reversing a “non-sensing” channel to “sensing” would be life-changing.

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Identification of the functional domain of p21WAF1/CIP1 that protects cells from cisplatin cytotoxicity

AJP Renal Physiology ◽

10.1152/ajprenal.00101.2005 ◽

2005 ◽

Vol 289 (3) ◽

pp. F514-F520 ◽

Cited By ~ 39

Author(s):

Fang Yu ◽

Judit Megyesi ◽

Robert L. Safirstein ◽

Peter M. Price

Keyword(s):

Dominant Negative ◽

Nuclear Antigen ◽

Functional Domain ◽

Binding Domains ◽

Cdk2 Activity ◽

Localization Signal ◽

Induced Apoptosis ◽

Proliferating Cell

The p21 cyclin-dependent kinase (cdk) inhibitor protects cells from cisplatin cytotoxicity in vivo and in vitro. However, the mechanism of protection is not known. Separate p21 domains are known to interact with several different proteins having proapoptotic functions. To investigate the mechanism of protection by p21, we have constructed adenoviruses encoding the different domains of p21. We were able to localize the protective activity to a region of 54 amino acids containing the cyclin-cdk interacting moiety. Other protein binding domains of p21, including the NH2-terminal procaspase-3 interactive region and the COOH-terminal region containing the proliferating cell nuclear antigen binding domain and the nuclear localization signal, had little protective effect on cisplatin cytotoxicity. The dependence of cisplatin cytotoxicity on cdk2 activity was also demonstrated because 1) cisplatin caused a marked increase in cdk2 activity, which was prevented by the p21 expression adenovirus, and 2) a cdk2 dominant-negative adenovirus also protected cells from cisplatin-induced apoptosis. Thus the data suggest that the mechanism of p21 protection is by direct inhibition of cdk2 activity and that cisplatin-induced apoptosis is caused by a cdk2-dependent pathway.

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