scholarly journals Prunetin Protects Against Dexamethasone-Induced Pancreatic Β-Cell Apoptosis via Modulation of p53 Signaling Pathway

2020 ◽  
Vol 15 (4) ◽  
pp. 1934578X2091632
Author(s):  
Suwattanee Kooptiwut ◽  
Kanokwan Samon ◽  
Namoiy Semprasert ◽  
Kanchana Suksri ◽  
Pa-Thai Yenchitsomanus
Keyword(s):  
Signaling Pathway ◽  
Cell Apoptosis ◽  
Caspase 3 ◽  
Control Level ◽  
B Cell Lymphoma ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
P53 Signaling ◽  
Protein Expressions ◽  
P53 Signaling Pathway

Long-term administration of dexamethasone results in insulin resistance and pancreatic β-cell apoptosis. Prunetin (an O-methylated isoflavone, a type of flavonoid) is demonstrated to protect diabetes, but the molecular mechanism of this protection is still unclear. This study thus aims to investigate how prunetin protects against dexamethasone-induced pancreatic β-cell apoptosis. Rat insulinoma (INS-1) cells were cultured in medium with or without dexamethasone in the presence or absence of prunetin or pifithrin-α, a p53 inhibitor. Cell apoptosis was measured by Annexin V/propidium iodide staining. Dexamethasone significantly induced INS-1 apoptosis but dexamethasone plus prunetin significantly reduced INS-1 apoptosis. Dexamethasone-treated INS-1 upregulated p53 protein expression; the induction of p53 was also reduced in the presence of RU486, a glucocorticoid receptor (GR) inhibitor. This suggested that dexamethasone induced P53 via GR. Dexamethasone-treated INS-1 significantly increased p53, Bax, and Rb protein expressions, whereas treatments of dexamethasone plus prunetin or pifithrin-α significantly decreased these protein expressions. In addition, dexamethasone significantly decreased B-cell lymphoma 2 (Bcl2), while dexamethasone plus prunetin or pifithrin-α significantly increased Bcl2. Dexamethasone significantly increased caspase-3 activity while co-treatment of dexamethasone plus prunetin or pifithrin-α significantly decreased caspase-3 activity to the control level. Taken together, our results revealed that prunetin protected against dexamethasone-induced pancreatic β-cells apoptosis via modulation of the p53 signaling pathway.

scholarly journals Intermittent-Hypoxia-Induced Autophagy Activation Through the ER-Stress-Related PERK/eIF2α/ATF4 Pathway is a Protective Response to Pancreatic β-Cell Apoptosis

2018 ◽  
Vol 51 (6) ◽  
pp. 2955-2971 ◽  
Author(s):  
Shuling Song ◽  
Jin Tan ◽  
Yuyang Miao ◽  
Zuoming Sun ◽  
Qiang  Zhang
Keyword(s):  
Er Stress ◽  
Signaling Pathway ◽  
Cell Apoptosis ◽  
Intermittent Hypoxia ◽  
Autophagic Vacuole ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Protective Response

Background/Aims: Intermittent hypoxia (IH) causes apoptosis in pancreatic β-cells, but the potential mechanisms remain unclear. Endoplasmic reticulum (ER) stress, autophagy, and apoptosis are interlocked in an extensive crosstalk. Thus, this study aimed to investigate the contributions of ER stress and autophagy to IH-induced pancreatic β-cell apoptosis. Methods: We established animal and cell models of IH, and then inhibited autophagy and ER stress by pharmacology and small interfering RNA (siRNA) in INS-1 cells and rats. The levels of biomarkers for autophagy, ER stress, and apoptosis were evaluated by immunoblotting and immunofluorescence. The number of autophagic vacuoles was observed by transmission electron microscopy. Results: IH induced autophagy activation both in vivo and in vitro, as evidenced by increased autophagic vacuole formation and LC3 turnover, and decreased SQSTM1 level. The levels of ER-stress-related proteins, including GRP78, CHOP, caspase 12, phosphorylated (p)-protein kinase RNA-like ER kinase (PERK), p-eIF2α, and activating transcription factor 4 (ATF4) were increased under IH conditions. Inhibition of ER stress with tauroursodeoxycholic acid or 4-phenylbutyrate partially blocked IH-induced autophagy in INS-1 cells. Furthermore, inhibition of PERK with GSK2606414 or siRNA blocked the ERstress-related PERK/eIF2α/ATF4 signaling pathway and inhibited autophagy induced by IH, which indicates that IH-induced autophagy activation is dependent on this signaling pathway. Promoting autophagy with rapamycin alleviated IH-induced apoptosis, whereas inhibition of autophagy with chloroquine or autophagy-related gene (Atg5 and Atg7) siRNA aggravated pancreatic β-cell apoptosis caused by IH. Conclusion: IH induces autophagy activation through the ER-stress-related PERK/eIF2α/ATF4 signaling pathway, which is a protective response to pancreatic β-cell apoptosis caused by IH.

scholarly journals Nodal induces apoptosis through activation of the ALK7 signaling pathway in pancreatic INS-1 β-cells

2012 ◽  
Vol 303 (1) ◽  
pp. E132-E143 ◽  
Author(s):  
Fang Zhao ◽  
Fengjie Huang ◽  
Mengxiong Tang ◽  
Xiaoming Li ◽  
Nina Zhang ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Cell Apoptosis ◽  
Caspase 3 ◽  
Biological Effects ◽  
Cell Mass ◽  
Type I ◽  
Β Cells ◽  
Β Cell ◽  
Akt Phosphorylation ◽  
Induced Apoptosis

We demonstrated previously that the activation of ALK7 (activin receptor-like kinase-7), a member of the type I receptor serine/threonine kinases of the TGF-β superfamily, resulted in increased apoptosis and reduced proliferation through suppression of Akt signaling and the activation of Smad2-dependent signaling pathway in pancreatic β-cells. Here, we show that Nodal activates ALK7 signaling and regulates β-cell apoptosis. We detected Nodal expression in the clonal β-cell lines and rodent islet β-cells. Induction of β-cell apoptosis by treatment with high glucose, palmitate, or cytokines significantly increased Nodal expression in clonal INS-1 β-cells and isolated rat islets. The stimuli induced upregulation of Nodal expression levels were associated with elevation of ALK7 protein and enhanced phosphorylated Smad3 protein. Nodal treatment or overexpression of Nodal dose- or time-dependently increased active caspase-3 levels in INS-1 cells. Nodal-induced apoptosis was associated with decreased Akt phosphorylation and reduced expression level of X-linked inhibitor of apoptosis (XIAP). Remarkably, overexpression of XIAP or constitutively active Akt, or ablation of Smad2/3 activity partially blocked Nodal-induced apoptosis. Furthermore, siRNA-mediated ALK7 knockdown significantly attenuated Nodal-induced apoptosis of INS-1 cells. We suggest that Nodal-induced apoptosis in β-cells is mediated through ALK7 signaling involving the activation of Smad2/3-caspase-3 and the suppression of Akt and XIAP pathways and that Nodal may exert its biological effects on the modulation of β-cell survival and β-cell mass in an autocrine fashion.

scholarly journals Downregulating Serine Hydroxymethyltransferase 2 Deteriorates Hepatic Ischemia-Reperfusion Injury through ROS/JNK/P53 Signaling in Mice

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Hao Wu ◽  
He Bai ◽  
Shigang Duan ◽  
Fangchao Yuan
Keyword(s):  
Signaling Pathway ◽  
Cell Apoptosis ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Liver Weight ◽  
Serine Hydroxymethyltransferase ◽  
Hepatic Ischemia ◽  
P53 Signaling ◽  
Hepatic Ischemia Reperfusion ◽  
P53 Signaling Pathway

Background. Serine hydroxymethyltransferase 2 (SHMT2) activity ensures that cells have a survival advantage in ischemic conditions and regulates redox homeostasis. In this study, we aimed to investigate the role of SHMT2 after hepatic ischemia-reperfusion (IR), which involves hypoxia, ischemic conditions, and cell apoptosis. Methods. A 70% IR model was established in C57BL/6J mice with or without SHMT2 knockdown. H&E staining, liver weight/body weight, serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels and cell apoptosis were tested to analyze liver damage and function. Then, the related cellular signals were probed. Results. The level of SHMT2 protein was significantly increased at 24 h and 48 h after IR (p<0.001). Mice in the shSHMT2 group showed more necrotic areas and histological damage at 24 h (p<0.01) after IR and higher levels of serum ALT and AST (p<0.05) compared with those of mice in the scramble group. After IR for 24 h, the expression of TUNEL in the shSHMT2 group was significantly higher than that in the scramble group, as shown by histological analysis (p<0.01). Mechanistically, the JNK/P53 signaling pathway was activated by IR, and knockdown of SHMT2 exacerbated hepatocyte apoptosis. Conclusions. Knockdown of SHMT2 worsens IR injury through the ROS/JNK/P53 signaling pathway. Our discovery expands the understanding of both molecular and metabolic mechanisms involved in IR. SHMT2 is a possible therapeutic target to improve the prognosis of liver transplantation (LT) and subtotal hepatectomy.

scholarly journals PPM1D Knockdown Suppresses Cell Proliferation, Promotes Cell Apoptosis, and Activates p38 MAPK/p53 Signaling Pathway in Acute Myeloid Leukemia

2020 ◽  
Vol 19 ◽  
pp. 153303382094231
Author(s):  
Bin Li ◽  
Jie Hu ◽  
Di He ◽  
Qi Chen ◽  
Suna Liu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Acute Myeloid Leukemia ◽  
Signaling Pathway ◽  
P38 Mapk ◽  
Protein Phosphatase ◽  
Cell Apoptosis ◽  
Myeloid Leukemia ◽  
P53 Signaling ◽  
P53 Signaling Pathway ◽  
Acute Myeloid

Objectives: This study was to explore the effect of protein phosphatase, Mg2+/Mn2+ dependent 1D knockdown on proliferation and apoptosis as well as p38 MAPK/p53 signaling pathway in acute myeloid leukemia. Methods: The expression of protein phosphatase, Mg2+/Mn2+ dependent 1D was detected in acute myeloid leukemia cell lines including SKM-1, KG-1, AML-193, and THP-1 cells, and normal bone marrow mononuclear cells isolated from healthy donors. The knockdown of protein phosphatase, Mg2+/Mn2+ dependent 1D was conducted by transfecting small interfering RNA into AML-193 cells and KG-1 cells. Results: The relative messenger RNA/protein expressions of protein phosphatase, Mg2+/Mn2+ dependent 1D were higher in SKM-1, KG-1, AML-193, and THP-1 cells compared with control cells (normal bone marrow mononuclear cells). After transfecting protein phosphatase, Mg2+/Mn2+ dependent 1D small interfering RNA into AML-193 cells and KG-1 cells, both messenger RNA and protein expressions of protein phosphatase, Mg2+/Mn2+ dependent 1D were significantly reduced, indicating the successful transfection. Most importantly, knockdown of protein phosphatase, Mg2+/Mn2+ dependent 1D suppressed cell proliferation and promoted cell apoptosis in AML-193 cells and KG-1 cells. In addition, knockdown of protein phosphatase, Mg2+/Mn2+ dependent 1D enhanced the expressions of p-p38 and p53 in AML-193 cells and KG-1 cells. The above observation suggested that protein phosphatase, Mg2+/Mn2+ dependent 1D knockdown suppressed cell proliferation, promoted cell apoptosis, and activated p38 MAPK/p53 signaling pathway in acute myeloid leukemia cells. Conclusion: Protein phosphatase, Mg2+/Mn2+ dependent 1D is implicated in acute myeloid leukemia carcinogenesis, which illuminates its potential role as a treatment target for acute myeloid leukemia.

scholarly journals Peroxiredoxin I deficiency increases pancreatic β‑cell apoptosis after streptozotocin stimulation via the AKT/GSK3β signaling pathway

2020 ◽  
Vol 22 (3) ◽  
pp. 1831-1838
Author(s):  
Mei‑Hua Jin ◽  
Gui‑Nan Shen ◽  
Ying‑Hua Jin ◽  
Hu‑Nan Sun ◽  
Xing Zhen ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Cell Apoptosis ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Peroxiredoxin I

scholarly journals Bcl-2 Modulation in p53 Signaling Pathway by Flavonoids: A Potential Strategy towards the Treatment of Cancer

2021 ◽  
Vol 22 (21) ◽  
pp. 11315
Author(s):  
Noor Rahman ◽  
Haroon Khan ◽  
Asad Zia ◽  
Asifullah Khan ◽  
Sajad Fakhri ◽  
...  
Keyword(s):  
Side Effects ◽  
Secondary Metabolites ◽  
Signaling Pathway ◽  
Antitumor Agents ◽  
Biological Activities ◽  
Human Life ◽  
B Cell Lymphoma ◽  
Cancer Etiology ◽  
P53 Signaling ◽  
P53 Signaling Pathway

Cancer is a major cause of death, affecting human life in both developed and developing countries. Numerous antitumor agents exist but their toxicity and low efficacy limits their utility. Furthermore, the complex pathophysiological mechanisms of cancer, serious side effects and poor prognosis restrict the administration of available cancer therapies. Thus, developing novel therapeutic agents are required towards a simultaneous targeting of major dysregulated signaling mediators in cancer etiology, while possessing lower side effects. In this line, the plant kingdom is introduced as a rich source of active phytochemicals. The secondary metabolites produced by plants could potentially regulate several dysregulated pathways in cancer. Among the secondary metabolites, flavonoids are hopeful phytochemicals with established biological activities and minimal side effects. Flavonoids inhibit B-cell lymphoma 2 (Bcl-2) via the p53 signaling pathway, which is a significant apoptotic target in many cancer types, hence suppressing a major dysregulated pathway in cancer. To date, there have been no studies reported which extensively highlight the role of flavonoids and especially the different classes of flavonoids in the modulation of Bcl-2 in the P53 signaling pathway. Herein, we discuss the modulation of Bcl-2 in the p53 signaling pathway by different classes of flavonoids and highlight different mechanisms through which this modulation can occur. This study will provide a rationale for the use of flavonoids against different cancers paving a new mechanistic-based approach to cancer therapy.

scholarly journals Doxycycline Induces Apoptosis of Brucella Suis S2 Strain-Infected HMC3 Microglial Cells by Activating Calreticulin-Dependent JNK/p53 Signaling Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Zhao Wang ◽  
Yanbai Wang ◽  
Huan Yang ◽  
Jiayu Guo ◽  
Zhenhai Wang
Keyword(s):  
Protein Expression ◽  
Signaling Pathway ◽  
Cell Apoptosis ◽  
Human Brucellosis ◽  
Protein Levels ◽  
P53 Signaling ◽  
Brucella Suis ◽  
The Central Nervous System ◽  
Infected Cells ◽  
P53 Signaling Pathway

Neurobrucellosis is a chronic complication of human brucellosis that is caused by the presence of Brucella spp in the central nervous system (CNS) and the inflammation play a key role on the pathogenesis. Doxycycline (Dox) is a widely used antibiotic that induces apoptosis of bacteria-infected cells. However, the mechanisms of Brucella inhibition of microglial apoptosis and Dox induction of apoptosis are still poorly understood. In this study, we found that Brucella suis S2 strain (B. suis S2) increased calreticulin (CALR) protein levels and inhbited HMC3 cell apoptosis. Hence, we constructed two HMC3 cell line variants, one with stable overexpression (HMC3-CALR) and one with low expression of CALR (HMC3-sh-CALR). CALR was found to decrease levels of p-JNK and p-p53 proteins, as well as suppress apoptosis in HMC3 cells. These findings suggest that CALR suppresses apoptosis by inhibiting the JNK/p53 signaling pathway. Next, we treated HMC3, HMC3-CALR and HMC3-sh-CALR cell lines with B. suis S2 or Dox. Our results demonstrate that B. suis S2 restrains the JNK/p53 signaling pathway to inhibit HMC3 cell apoptosis via increasing CALR protein expression, while Dox plays the opposite role. Finally, we treated B. suis S2-infected HMC3 cells with Dox. Our results confirm that Dox induces JNK/p53-dependent apoptosis in B. suis S2-infected HMC3 cells through inhibition of CALR protein expression. Taken together, these results reveal that CALR and the JNK/p53 signaling pathway may serve as novel therapeutic targets for treatment of neurobrucellosis.

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