scholarly journals PI3K–AKT Pathway Protects Cardiomyocytes Against Hypoxia-Induced Apoptosis by MitoKATP-Mediated Mitochondrial Translocation of pAKT

2018 ◽  
Vol 49 (2) ◽  
pp. 717-727 ◽  
Author(s):  
Hua-Pei Song ◽  
Zhi-Gang Chu ◽  
Dong-Xia Zhang ◽  
Yong-Ming Dang ◽  
Qiong Zhang

Background/Aims: The phosphatidylinositol-3-kinase -AKT (PI3K-AKT) is an important intracellular signal pathway in regulating cell proliferation, differentiation and apoptosis. In previous studies, we’ve demonstrated that PI3K–AKT pathway protects cardiomyocytes from ischemic and hypoxic apoptosis through mitochondrial function. However, the molecular mechanisms underlying hypoxia-induced cardiomyocyte apoptosis via PI3K-AKT pathway remain ill-defined. Here, we addressed this question. Methods: Cardiomyocytes were exposed to hypoxia, with/without different inhibitors and then protein levels were assessed by Western blotting. Results: We found that the PI3K–AKT pathway was activated in cardiomyocytes that were exposed to hypoxia. Moreover, the phospho-AKT (pAKT) translocated from cytosol to mitochondria via mitochondrial adenosine triphosphate-dependent potassium (mitoKATP), leading to an increase in cytochrome c oxidase (CcO) activity to suppress apoptosis. On the other hand, the mitoKATP specific blocker, 5-hydroxydecanote (5-HD), or suppression of CcO using siRNA, inhibited the pAKT mitochondrial translocation to maintain the CcO activity, resulting in mitochondrial dysfunction and cellular apoptosis induced by hypoxia. Conclusion: These findings suggest that the anti-apoptotic effect of the PI3K-AKT pathway through pAKT translocation to mitochondrial via mitoKATP may be conducted through modification of CcO activity.

2020 ◽  
Vol 15 (1) ◽  
pp. 274-283
Author(s):  
Bo Zheng ◽  
Tao Chen

AbstractAmong astrocyte tumors, glioblastoma (GBM) is the most malignant glioma, highly aggressive and invasive, with extremely poor prognosis. Previous research has reported that microRNAs (miRNAs) participate in the progression of many cancers. Thus, this study aimed to explore the role and the underlying mechanisms of microRNA (miR)-489-3p in GBM progression. The expression of miR-489-3p and brain-derived neurotrophic factor (BDNF) mRNA was measured by quantitative real-time polymerase chain reaction. Western blot analysis was used to detect BDNF protein and the PI3K/AKT pathway-related protein. Cell proliferation, apoptosis, migration, and invasion were analyzed using CKK-8 assay, flow cytometry, and transwell assay, respectively. The interaction between BDNF and miR-489-3p was explored by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. MiR-489-3p was down-regulated and BDNF was up-regulated in GBM tissues and cells. MiR-489-3p re-expression or BDNF knockdown inhibited GBM cell proliferation, migration, and invasion, and promoted apoptosis. BDNF was a target of miR-489-3p, and BDNF up-regulation reversed the effects of miR-489-3p on GBM cells. The protein levels of p-AKT and p-PI3K were notably reduced in GBM cells by overexpression of miR-489-3p, but were rescued following BDNF up-regulation. Therefore, miR-489-3p inhibited proliferation, migration, and invasion, and induced apoptosis, by targeting the BDNF-mediated PI3K/AKT pathway in GBM, providing new strategies for clinical treatment of GBM.


2022 ◽  
Vol 12 (5) ◽  
pp. 947-952
Author(s):  
Jun Zhang ◽  
Yuying Gao ◽  
Peng Chen ◽  
Yu Zhou ◽  
Sheng Guo ◽  
...  

This study was to explore the mechanism by how exosomes (exo) derived from BMSCs affects cardiomyocyte apoptosis. BMSCs were isolated and incubated with cardiomyocytes while the cardiomyocytes were exposed to sevoflurane or DMSO treatment. Apoptotic cells were calculated and level of apoptosis related proteins was detected by Western blot. Through transfection with microRNA-(miRNA)-312 inhibitor, we evaluated the effect of BMSC-exo on the sevoflurane-induced apoptosis. Sevoflurane significantly inhibited the viability of cardiomyocytes and induced cardiomyocyte apoptosis. Besides, sevoflurane decreased the expression of miR-312 and enhanced Bax expression in cardiomyocytes through restraining the phosphorylation of MAPK/ERK. Treatment with BMSC-exo, however, activated MAPK/ERK signaling by up-regulating miR-312, thereby inhibiting cardiomyocyte apoptosis, promoting cardiomyocyte proliferation, and elevating the level of Bcl-2. In conclusion, BMSC-exo-derived miR-312 inhibits sevoflurane-induced cardiomyocyte apoptosis by activating PI3K/AKT signaling pathway.


2018 ◽  
Vol 50 (6) ◽  
pp. 2086-2096 ◽  
Author(s):  
Xiaohong  Zhang ◽  
Can Xiao ◽  
Hong Liu

Background/Aims: Ganoderic acid A (GAA) isolated from Ganoderma lucidum, shows various benefit activities, such as anti-tumor activity, anti-HIV activity and hepatoprotective activity. However, the potential effects of GAA on hypoxia-induced injury of cardiomyocytes are still unclear. In this study, we aimed to reveal the effects of GAA on hypoxic-induced H9c2 cell injury, as well as potential underlying molecular mechanisms. Methods: Rat H9c2 cardiomyocytes were cultured in hypoxia condition with different doses of GAA. Cell viability and apoptosis were detected by CCK-8 assay and flow cytometry, respectively. qRT-PCR was performed to assess the expression levels of microRNA-182-5p (miR-182-5p) and phosphatase and tensin homologue (PTEN). Cell transfection was conducted to change the expression levels of miR-182-5p and PTEN in H9c2 cells. Finally, protein levels of key factors involved in cell proliferation, cell apoptosis and PTEN/PI3K/AKT pathway were evaluated using western blotting. Results: Hypoxia treatment significantly induced H9c2 cell viability loss and apoptosis. GAA incubation remarkably protected H9c2 cells from hypoxia-induced viability loss, proliferation inhibition and apoptosis. In addition, GAA obviously enhanced the expression level of miR-182-5p in H9c2 cells. Suppression of miR-182-5p notably alleviated the protective effects of GAA on hypoxia-treated H9c2 cells. Furthermore, miR-182-5p negatively regulated the mRNA and protein levels of PTEN in H9c2 cells. GAA attenuated hypoxia-induced inactivation of PI3K/AKT pathway in H9c2 cells by up-regulating miR-182-5p and then down-regulating PTEN. Conclusion: GAA protected rat H9c2 cardiomyocytes from hypoxia-induced injury might via up-regulating miR-182-5p, down-regulating PTEN and then activating PI3K/AKT signaling pathway.


2019 ◽  
Vol 30 (10) ◽  
pp. 1182-1197 ◽  
Author(s):  
Jing Song ◽  
Yaqi Wang ◽  
Xiao Yuan ◽  
Qiuxia Ji ◽  
Cunhui Fan ◽  
...  

Previously, we had shown that high magnitude stretch (HMS), rather than low magnitude stretch (LMS), induced significant apoptosis of skeletal muscle C2C12 myoblasts. However, the molecular mechanism remains obscure. In this study, we found that p53 protein accumulated in the nucleus of LMS-loaded cells, whereas it translocated into mitochondria of HMS-loaded cells. Knocking down endogenous p53 by shRNA abrogated HMS-induced apoptosis. Furthermore, we demonstrated that overaccumulation of reactive oxygen species (ROS) during HMS-inactivated AKT that was activated in LMS-treated cells, which accounted for the distinct p53 subcellular localizations under HMS and LMS. Blocking ROS generation by N-acetylcysteine (NAC) or overexpressing constitutively active AKT vector (CA-AKT) inhibited HMS-incurred p53 mitochondrial translocation and promoted its nuclear targeting. Moreover, both NAC and CA-AKT significantly attenuated HMS-induced C2C12 apoptosis. Finally, we found that Ser389 phosphorylation of p53 was a downstream event of ROS-inactivated AKT pathway, which was critical to p53 mitochondrial trafficking during HMS stimuli. Transfecting p53-shRNA C2C12s with the mutant p53 (S389A) that was unable to target p53 to mitochondria underwent significantly lower apoptosis than transfection with wild-type p53. Altogether, our study uncovered that mitochondrial localization of p53, resulting from p53 Ser389 phosphorylation through ROS-inactivated AKT pathway, prompted C2C12 myoblast apoptosis during HMS stimulation.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1415
Author(s):  
Shanshan Chen ◽  
Changping Deng ◽  
Wenyun Zheng ◽  
Shihui Li ◽  
Yuping Liu ◽  
...  

Cannabidiol (CBD), a primary bioactive phytocannabinoid extracted from hemp, is reported to possess potent anti-tumorigenic activity in multiple cancers. However, the effects of CBD on bladder cancer (BC) and the underlying molecular mechanisms are rarely reported. Here, several experiments proved that CBD promoted BC cells (T24, 5637, and UM-UC-3) death. For example, T24 cells were treated with 12 µM CBD for 48 h, flow cytometry analysis demonstrated that early and late apoptotic cells were accounted for by 49.91%, indicating CBD enhanced cell apoptosis ability. To deeper explore molecular mechanisms, the CBD-treated T24 cell transcriptome libraries were established. KEGG analysis implied that the significantly changed genes were enriched in the PI3K/Akt pathway. qRT-PCR and Western blot assays verified that CBD regulated BC cells growth and migration and induced apoptosis by inactivating the PI3K/Akt pathway. Meanwhile, the developed chitosan to wrap CBD-loaded PLGA nanoparticles can significantly enhance the adhesion of the material to the mouse bladder wall, and the binding efficiency of mucin to chitosan-PLGA nanoparticles reached 97.04% ± 1.90%. In summary, this work demonstrates that CBD may become a novel reliable anticancer drug and the developed intravesical adhesion system is expected to turn into a potential means of BC chemotherapy drug delivery.


2021 ◽  
Author(s):  
Roderick C Slieker ◽  
Louise A Donnelly ◽  
Hugo Fitipaldi ◽  
Gerard A Bouland ◽  
Giuseppe N. Giordano ◽  
...  

Type 2 diabetes is a multifactorial disease with multiple underlying aetiologies. To address this heterogeneity a previous study clustered people with diabetes into five diabetes subtypes. The aim of the current study is to investigate the aetiology of these clusters by comparing their molecular signatures. In three independent cohorts, in total 15,940 individuals were clustered based on five clinical characteristics. In a subset, genetic- (N=12828), metabolomic- (N=2945), lipidomic- (N=2593) and proteomic (N=1170) data were obtained in plasma. In each datatype each cluster was compared with the other four clusters as the reference. The insulin resistant cluster showed the most distinct molecular signature, with higher BCAAs, DAG and TAG levels and aberrant protein levels in plasma enriched for proteins in the intracellular PI3K/Akt pathway. The obese cluster showed higher cytokines. A subset of the mild diabetes cluster with high HDL showed the most beneficial molecular profile with opposite effects to those seen in the insulin resistant cluster. This study showed that clustering people with type 2 diabetes can identify underlying molecular mechanisms related to pancreatic islets, liver, and adipose tissue metabolism. This provides novel biological insights into the diverse aetiological processes that would not be evident when type 2 diabetes is viewed as a homogeneous disease


2021 ◽  
Author(s):  
Abhishek Pandeya ◽  
Anup Mishra ◽  
Raj Kumar Khalko ◽  
Sukhveer Singh ◽  
Nishant Singh ◽  
...  

Abstract Human Cytomegalovirus (HCMV), a prototypic member of the Beta-herpesvirinae subfamily, mainly responsible for congenital disabilities in newborns, cause opportunistic infections in immunocompromised individuals. Its seroprevalence varies across the globe ranging from 50–70 percent in developed countries to 90–100 percent in developing countries. Causing latent infections in the immunocompetent host suggests that it employs several strategies to escape the wrath of the host’s antiviral mechanisms. Apoptosis is an innate cellular response to viral infection, and downregulation of this mechanism by HCMV is a well-established phenomenon. HCMV utilizes its proteins, RNA and miRNA in regulating this response to establish a productive infection in the host. The role of HCMV miRNAs on cellular apoptosis is very interesting, where some miRNAs downregulate but a few upregulate this process. In the present study, we report the antiapoptotic activity of HCMV miRNA, miR-UL-70-3p, on H2O2 induced apoptosis in HEK293T cells. The ectopic expression of this HCMV miRNA in HEK293T cells downregulate the apoptosis, and continuing studies reveal that the proapoptotic gene, Modulator of Apoptosis Protein-1 (MOAP1), is a functional target for this miRNA. We verified the functionality of the binding site predicted in the 3'UTR of MOAP1 in our earlier studies through dual luciferase-based assays using both the wild and mutant 3'UTR’s of MOAP1. The MOAP1 protein levels were significantly downregulated by the miR-UL70-3p, suggesting that the MOAP1 mRNA was degraded after binding with the miR-UL70-3p. Further, the extent of MOAP1 mRNA and its protein inhibitions by HCMV miR-UL70-3p and siRNA of MOAP1 were compared and found that the siRNA of MOAP1 inhibits 69.52 percent of mRNA and 35.67 percent of MOAP1 protein; while the miR-UL70-3p inhibits 46.66 percent MOAP1 mRNA and 21.05 percent MOAP1 protein. Though the inhibitory activity of miR-UL70-3p is not equal to the siRNA of MOAP1, but it was significant enough in reversing the H2O2 induced apoptosis in HEK293T cells. These results confirm that hcmv-miR-UL70-3p downregulates H2O2 induced apoptosis in HEK293T cells by targeting the 3'UTR of MOAP1 mRNA.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2102-2102
Author(s):  
Medhat Shehata ◽  
Susanne Schnabl ◽  
Dita Demirtas ◽  
Josef D. Schwarzmeier ◽  
Martin Hilgarth ◽  
...  

Abstract Inhibition of apoptosis and long survival leads to accumulation of the leukemic cells in B cell chronic lymphocytic leukemia (B-CLL). This could be due to activation of anti-apoptotic cascades in CLL cells through interaction with their lymphoid microenvironment. Therefore, we investigated the role of tumor microenvironment in prolongation of survival of B-CLL cells and activation of the potent anti-apoptotic PI3-K/Akt pathway. Stromal fibroblasts of bone marrow (BMFs), spleen (SF) and lymph gland (LGF) were used as an in vitro model for lymphoid microenvironment and we tested their ability to inhibit spontaneous apoptosis of B-CLL cells. Co-culture of B-CLL cells with human BMFs, LGF, and SF significantly inhibited apoptosis and prolonged survival of the leukemic cells in comparison to suspension cultures and to co-cultures with fibroblasts obtained from non-lymphoid organs. Trans-well culture experiments indicated that cell-cell interaction and soluble mediators are essential for this supportive effect. To explore the involvement of PI3-K/Akt pathway in the anti-apoptotic effect of stromal fibroblasts, co-cultures were performed in presence of PI3-K inhibitors (wortmannin or Ly294002) or siRNAs against PI3-K (p110ß subunit) and Akt1. These inhibitors significantly reduced the supportive effect of stromal fibroblasts and induced apoptosis in B-CLL cells. Interestingly, the leukemic cells were far more sensitive to PI3-K inhibition than T cells, monocytes and fibroblasts. Induction of apoptosis was associated with a significant decrease in the intracellular PIP3, PI3-K, PDK1 and Akt1, NF-kappa B, IKK and de-phosphorylation/activation of tumor suppressor protein PTEN. Studies using phosphospecific anti-PTEN antibody demonstrated that PBMC of CLL patients (n=40) highly express a phosphorylated form of PTEN. The results demonstrate that the PI3-K/Akt pathway is involved in inhibition of apoptosis of B-CLL cells and suggest that interaction of the leukemic cells with lymphoid microenvironment maintains the activation of this pathway. The data also suggest that targeting this pathway represents a new option for designing novel therapeutic strategies in B-CLL.


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