scholarly journals The role of activating transcription factor 6 in hydroxycamptothecin-induced fibroblast autophagy and apoptosis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jin Tao ◽  
Hui Chen ◽  
Xiaolei Li ◽  
Jingcheng Wang

Abstract Background The over-proliferation of fibroblasts is considered to be the main cause of scar adhesion after joint surgery. Hydroxycamptothecin (HCPT), though as a potent antineoplastic drug, shows preventive effects on scar adhesion. This study aimed to investigate the role of activating transcription factor 6 (ATF-6) in the HCPT-induced inhibition of fibroblast viability. Methods The cell counting kit-8 (CCK-8) assay, western blot analysis, lentivirus-mediated gene silencing, transmission electron microscopy (TEM) analysis, immunofluorescent staining for autophagy-related protein light chain 3 (LC3) were used to explore the effect of HCPT on triggering fibroblast apoptosis and inhibiting fibroblast proliferation, and the involvement of possible signaling pathways. Results It was found that HCPT exacerbated fibroblast apoptosis and repressed its proliferation. Subsequently, endoplasmic reticulum stress (ERS)-related proteins were determined by western blot prior to ATF6 p50 was screened out and reexamined after it was silenced. As a result, ATF6-mediated ERS played a role in HCPT-induced fibroblast apoptosis. Autophagy-related proteins and autophagosomes were detected after the HCPT administration using western blot and TEM analyses, respectively. Autophagy was activated after the HCPT treatment. With the co-treatment of autophagy inhibitor 3-methyladenine (3-MA), both the western blot analysis and the CCK-8 assay showed inhibited autophagy, which indicated that the effect of HCPT on fibroblast proliferation was partially reversed. Besides, the LC3 immunofluorescence staining revealed suppressed autophagy after silencing ATF6 p50. Conclusion Our results demonstrate that HCPT acts as a facilitator of fibroblast apoptosis and inhibitor of fibroblast proliferation for curbing the postoperative scar adhesion, in which the ATF6-mediated ERS pathway and autophagy are involved.

2006 ◽  
Vol 290 (4) ◽  
pp. G729-G736 ◽  
Author(s):  
Atsushi Masamune ◽  
Masahiro Satoh ◽  
Jun Hirabayashi ◽  
Kenichi Kasai ◽  
Kennichi Satoh ◽  
...  

Galectin-1 is a β-galactoside-binding lectin. Previous studies have shown that galectin-1 was expressed in fibroblasts of chronic pancreatitis and of desmoplastic reaction associated with pancreatic cancer. These fibroblasts are now recognized as activated pancreatic stellate cells (PSCs). Here, we examined the role of galectin-1 in cell functions of PSCs. PSCs were isolated from rat pancreatic tissue and used in their culture-activated phenotype unless otherwise stated. Expression of galectin-1 was assessed by Western blot analysis, RT-PCR, and immunofluorescent staining. The effects of recombinant galectin-1 on chemokine production and proliferation were evaluated. Activation of transcription factors was assessed by EMSA. Activation of MAPKs was examined by Western blot analysis using anti-phosphospecific antibodies. Galectin-1 was strongly expressed in culture-activated but not freshly isolated PSCs. Recombinant galectin-1 increased proliferation and production of monocyte chemoattractant protein-1 and cytokine-induced neutrophil chemoattractant-1. Galectin-1 activated ERK, JNK, activator protein-1, and NF-κB, but not p38 MAPK or Akt. Galectin-1 induced proliferation through ERK and chemokine production mainly through the activation of NF-κB and in part by JNK and ERK pathways. These effects of galectin-1 were abolished in the presence of thiodigalactosie, an inhibitor of β-galactoside binding. In conclusion, our results suggest a role of galectin-1 in chemokine production and proliferation through its β-galactoside binding activity in activated PSCs.


Reproduction ◽  
2020 ◽  
Vol 160 (2) ◽  
pp. 293-305
Author(s):  
Hui-Qin Mo ◽  
Fu-Ju Tian ◽  
Xiao-Ling Ma ◽  
Yu-Chen Zhang ◽  
Cheng-Xi Zhang ◽  
...  

Protein disulfide isomerase 3 (PDIA3) is a chaperone protein that modulates the folding of newly synthesized glycoproteins, has isomerase and redox activity, and has been implicated in the pathogenesis of many diseases. However, the role of PDIA3 in pregnancy-associated diseases remains largely unknown. Our present study reveals a key role for PDIA3 in the biology of placental trophoblasts from women with preeclampsia (PE). Immunohistochemistry and Western blot analysis revealed that PDIA3 expression was decreased in villous trophoblasts from women with PE compared to normotensive pregnancies. Further, using a Cell Counting Kit-8 assay, flow cytometry, and 5-ethynyl-2’-deoxyuridine (EdU) staining, we found that siRNA-mediated PDIA3 knockdown significantly promoted apoptosis and inhibited proliferation in the HTR8/SVneo cell line, while overexpression of PDIA3 reversed these effects. Furthermore, RNA sequencing and Western blot analysis demonstrated that knockdown of PDIA3 inhibited MDM2 protein expression in HTR8 cells, concurrent with marked elevation of p53 and p21 expression. Conversely, overexpression of PDIA3 had the opposite effects. Immunohistochemistry and Western blot further revealed that MDM2 protein expression was downregulated and p21 was increased in trophoblasts of women with PE compared to women with normotensive pregnancies. Our findings indicate that PDIA3 expression is decreased in the trophoblasts of women with PE, and decreased PDIA3 induces trophoblast apoptosis and represses trophoblast proliferation through regulating the MDM2/p53/p21 pathway.


2019 ◽  
Vol 52 (1) ◽  
Author(s):  
Hao Hu ◽  
Jiawei Wu ◽  
Xiaofan Yu ◽  
Junling Zhou ◽  
Hua Yu ◽  
...  

Abstract Background Our previous study showed that knockdown of long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) attenuated myocardial apoptosis in mouse acute myocardial infarction (AMI). This study aims to explore whether MALAT1 enhanced cardiomyocyte apoptosis via autophagy regulation and the underlying mechanisms of MALAT1 regulating autophagy. Methods Cardiomyocytes were isolated from neonatal mice and then stimulated with hypoxia/reoxygenation (H/R) injury to mimic AMI. The autophagy level was assessed using GFP-LC3 immunofluorescence and western blot analysis of autophagy-related proteins. RNA pull-down and RNA immunoprecipitation (RIP) was performed to analyze the binding of MALAT1 and EZH2. Chromatin immunoprecipitation (ChIP) assay was performed to analyze the binding of TSC2 promoter and EZH2. The cell apoptosis was evaluated using TUNEL staining and western blot analysis of apoptosis-related proteins. Results H/R injury increased MALAT1 expression in cardiomyocytes. Furthermore, MALAT1 overexpression inhibited, whereas MALAT1 knockdown enhanced the autophagy of cardiomyocytes. Moreover, MALAT1 overexpression recruited EZH2 to TSC2 promoter regions to elevate H3K27me3 and epigenetically inhibited TSC2 transcription. Importantly, TSC2 overexpression suppressed mTOR signaling and then activated the autophagy. Further results showed that MALAT1 inhibited proliferation and enhanced apoptosis of cardiomyocytes through inhibiting TSC2 and autophagy. Conclusion These findings demonstrate that the increased MALAT1 expression induced by H/R injury enhances cardiomyocyte apoptosis through autophagy inhibition by regulating TSC2-mTOR signaling.


2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Rebekah Sian Hwee Yu ◽  
Daryll Baker ◽  
David Abraham ◽  
Janice Tsui

Objectives Erythropoietin (Epo) has tissue-protective effects in response to injury, acting through the EpoR-βcR heteroreceptor. We have previously demonstrated the presence and interaction of the EpoR and βcR in human skeletal muscle. Here we aim to investigate the potential cytoprotective effects of Epo and an Epo-derivative (ARA-290) in a human in vitro model of skeletal muscle and establish a potential downstream signalling pathway utilised in protecting cells from apoptosis (including Jak-2, PI3k/Akt, NFkB). Methods Gastrocnemius muscle biopsies were obtained from patients with critical limb ischaemia and control samples were obtained from non-ischaemic patients. Human myoblasts were isolated from muscle biopsies, cultured, and allowed to differentiate into myotubes in order to investigate the cytoprotective effects of Epo and ARA-290 on myotubes subjected to simulated ischaemia. The PI3k inhibitors, LY294002 and wortmannin, were then used to determine the role of PI3k/Akt pathway in mediating cytoprotection. Following this, inhibitors against the upstreatm (Jak-2) and downstream (NFkB) molecules were also investigated. Western blot analysis, using the pro-apoptotic marker cleaved caspase-3 was performed and compared with levels of Akt and phosphorylated-Akt, using western blot analysis. Results Exogenous administration of Epo and ARA-290 were able to ameliorate the ischaemia-induced apoptosis on isolated human myotubes as shown by a significant reduction in cleaved caspase-3 expression. Addition of all inhibitors, to ARA-290 or Epo pre-treated cells, abolished the reduction in apoptosis. Conclusion The ability of ARA-290 to attenuate apoptosis in human myotubes undergoing ischaemic insult suggests a potential role in tissue protection in skeletal muscle injury. We propose that the PI3k/Akt signalling pathway is involved in mediating this cytoprotection.


2019 ◽  
Vol 51 (10) ◽  
pp. 1008-1015 ◽  
Author(s):  
Shusheng Qiu ◽  
Wei Hu ◽  
Qiuhong Ma ◽  
Yi Zhao ◽  
Liang Li ◽  
...  

Abstract Tumor necrosis factor α-induced protein 8-like-1 (TIPE1) functions as an activator or a repressor in a tumor cell type-specific manner. However, the role of TIPE1 in breast cancer, especially regarding metastasis, is unknown. In this study, we aimed to investigate the TIPE1 expression in breast cancer tissues, the biological functions, and the underlying mechanisms of TIPE1 regarding the metastatic properties of breast cancer cells. The results of immunohistochemical staining and western blot analysis indicated that TIPE1 expression was associated with tumor size and lymph node metastasis, and the expression of TIPE1 was downregulated in the tissues of patients with lymph node metastasis. Transwell and wound healing assay results showed that TIPE1 inhibited the invasive and migratory capacities of breast cancer cells. Moreover, the epithelial-mesenchymal transition (EMT) was suppressed in TIPE1-overexpressing cells, as demonstrated by western blot analysis. In addition, western blot analysis also showed that TIPE1 reduced the expression levels of MMP2 and MMP9 and decreased the phosphorylation level of ERK. These results suggested that TIPE1 might suppress the invasion and migration of breast cancer cells and inhibit EMT primarily via the ERK signaling pathway. Our findings revealed the anti-tumor metastasis role of TIPE1 in breast cancer and TIPE1 might be a new candidate prognostic indicator and a potential molecular target for the treatment of breast cancer.


2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Dong Leng ◽  
Xiaoxi Huang ◽  
Jiawen Yi ◽  
Hongying Zhao ◽  
Yuhui Zhang

Background. Idiopathic pulmonary fibrosis (IPF), the most common interstitial lung disease, arises from transforming growth factor beta 1- (TGFβ1-) induced aberrant fibroproliferation in response to epithelial injury. The TGFβ1 antagonists—hyaluronidases (HYALs)—have been used to clinically treat pulmonary fibrosis. This study focused on characterizing the effect of HYAL1, the main enzyme in hyaluronan degradation, on human lung fibroblast proliferation and apoptosis, and elucidating its potential underlying mechanism of action. Methods. We first performed microarray data mining of previously published gene expression datasets to identify key gene signatures in IPF lung tissues. HYAL1 expression levels in IPF and normal lung tissues were then characterized using immunohistochemistry followed by real-time quantitative reverse transcription-PCR (qRT-PCR) and western blot analysis on isolated fibroblasts from fresh lung tissues of IPF and healthy donors. A human fetal lung fibroblast HFL-1 cell line, which was used in place of primary lung fibroblasts, was used to assess the proliferative or apoptotic effects associated with lentiviral-induced HYAL1 overexpression using CCK-8 cell proliferation assay and Annexin V-APC staining. The identification of potentially associated molecular pathways was performed using microarray analysis followed by qRT-PCR and western blot analysis. Results. Lung tissue microarray data mining and immunohistochemistry revealed significantly downregulation of HYAL1 in IPF lung tissue. However, HYAL1 expression level in IPF fibroblasts was significantly upregulated at the mRNA level, but not altered at the protein level. HYAL1 overexpression in HFL-1 fibroblasts reduced fibroproliferation modestly but did not promote apoptosis. In addition, HYAL1 overexpression led to concomitant transcription factor downregulation, bone morphogenetic protein receptor 2 (BMPR2) signaling activation, but had no effect on TGFβ receptor 2 (TGFβR2) signaling. Conclusions. We showed that HYAL1 overexpression could prevent HFL-1 fibroproliferation. Furthermore, our findings suggest that transcriptional regulators and BMP receptor signaling may be involved in HYAL1 modulation in IPF therapy.


2020 ◽  
Vol 318 (1) ◽  
pp. C73-C82 ◽  
Author(s):  
Yan-Hui Li ◽  
Dong Zhu ◽  
Zongbing Cao ◽  
Yanwei Liu ◽  
Jian Sun ◽  
...  

Our objective was to investigate the role of primary cilia in low-magnitude, high-frequency vibration (LMHFV) treatment of MC3T3-E1 osteoblasts (OBs). We used chloral hydrate (CH), which has a well-characterized function in chemically removing primary cilia, to elucidate the role of primary cilia in LMHFV-induced OB osteogenic responses through cell viability assay, Western blot analysis, real-time quantitative RT-PCR, and histochemical staining methods. We observed a significant, 30% decrease in the number of MC3T3-E1 OBs with primary cilia (reduced from 64.3 ± 5%) and an approximately 50% reduction in length of primary cilia (reduced from 3 ± 0.8 μm) after LMHFV stimulation. LMHFV stimulation upregulated protein expression of the bone matrix markers collagen 1 (COL-1), osteopontin (OPN), and osteoclacin(OCN) in MC3T3-E1 OBs, indicating that LMHFV induces osteogenesis. High-concentration or long-duration CH exposure resulted in inhibition of MC3T3-E1 OB survival. In addition, Western blot analysis and RT-PCR revealed that CH treatment prevented LMHFV-induced osteogenesis. Furthermore, decreased alkaline phosphate activity, reduced OB differentiation, mineralization, and maturation were observed in CH-pretreated and LMHFV-treated OBs. We showed that LMHFV induces morphological changes in primary cilia that may fine-tune their mechanosensitivity. In addition, we demonstrated the significant inhibition by CH of LMHFV-induced OB mineralization, maturation, and differentiation, which might reveal the critical role of primary cilia in the process.


2021 ◽  
Author(s):  
Yue Li ◽  
Mingxu Fu ◽  
Ling Guo ◽  
Xiaoxiao Sun ◽  
Yuhang Chen ◽  
...  

Abstract Background: Metastases and recurrence of ovarian cancer after surgery and chemotherapy account for most cancer-related deaths, yet the mechanism underlying metastases and recurrence remains poorly understood. Recent evidence demonstrates that although long-lasting cells were considered tumor suppressors, senescent cancer cells, can induce the metastases and recurrence. In this study, we focused on the fate of ovarian cancer cells treated with carboplatin and explored the mechanism underlying ovarian cancer cell recovery from chemotherapy-induced senescence. Methods: SÁ-β-galactosidase staining was used to detect the impact of carboplatin on senescence of ovarian cancer cells. Cell proliferation was determined using direct cell counting, clone formation assay and 3D tumor spheroid formation assay. Lentivirus-mediated transduction was used to silence or upregulate EGFR expression. Quantitative real-time PCR and western blot analysis validated the efficacy of the knockdown or overexpression effect. Immunofluorescence staining and western blot analysis were used to examined the expression of EGFR and NF-KB. Cell death was determined using trypan blue staining assay. Results: Ovarian cancer cells treated by carboplatin exhibit a senescence-like phenotype indicated by SA-β-galactosidase positive staining. Importantly, carboplatin-induced senescence-like phenotype is reversible. In ovarian cancer cells, EGFR positively regulated cells proliferation, decreased carboplatin-induced senescence and upregulated the NF-κB1 protein level. EGFR/NF-κB1 upregulation promoted the recovery of ovarian cancer cells from senescence and chemoresistance to carboplatin. Conclusions: Ovarian cancer cells treated with carboplatin displayed a reversible senescence-like phenotype that could be combined with EGFR or NF-κB1 inhibitors to improve treatment effects.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Muneera R Kapadia ◽  
Jason W Eng ◽  
Jozef Murar ◽  
Qun Jiang ◽  
Melina R Kibbe

Introduction: Nitric oxide (NO) is known to inhibit vascular smooth muscle cell (VSMC) proliferation by modulating cell cycle proteins. The 26S proteasome tightly regulates the degradation of most cell cycle proteins. Therefore, we previously studied the relationship between NO and the 26S proteasome, and found that NO directly inhibits 26S proteasome catalytic activity. The purpose of this study was two-fold: to determine the effect of NO on 26S proteasome subunit expression, and to determine the intracellular localization of these subunits. Methods: Protein expression was examined using western blot analysis conducted on rat aortic VSMC exposed to varying concentrations of the NO donor S-nitroso-N-acetylpenicillamine (SNAP, 125–1000 μM) for 24 hours. Intracellular localization was conducted with immunofluorescent staining of VSMC ± exposure to SNAP (500 μM). VSMC were also fractionated into their nuclear and cytoplasmic components and western blot analysis was conducted to confirm localization. Results: Of the 26S proteasome subunits examined, the α5, α6, β1, and inducible β1 subunits demonstrated increased protein expression with increasing concentrations of NO. However, β2, inducible β2, β5, and inducible β5 protein expression did not change with NO exposure. Immunofluorescent staining of VSMC for these subunits confirmed these results. Additionally, each of these subunits showed a distinct pattern of staining: the α5 subunit was mostly perinuclear, the α6 subunit appeared mostly nuclear, and the β1 and inducible β1 subunits were mostly cytoplasmic. Western blot analysis following nuclear and cytoplasmic separation confirmed that α5, β1, and inducible β1 subunits were mostly in the cytoplasmic fraction. Interestingly, while the α6 subunit localizes to the nucleus by immunofluorescent staining, western blotting showed it to be mostly in the cytoplasmic fraction, indicating that its cellular distribution is perinuclear. Conclusion: Our data indicate that the 26S proteasome subunits have distinct patterns of intracellular localization, and are differentially regulated by NO. Understanding the relationship between NO and the 26S proteasome provides insight into the mechanism by which NO inhibits VSMC proliferation.


Author(s):  
Nur Basirah Ghazali ◽  
Michael Steele ◽  
David Koh ◽  
Adi Idris

Abstract Disruption in circadian rhythm affects the production of inflammatory cytokines. Understanding how it behaves in diseased conditions is essential. Despite the role of the interleukin-1β (IL-1β), a potent inflammatory cytokine, in human diseases, little is known about the steady-state circadian rhythm of IL-1β in healthy individuals. This short study investigates the diurnal pattern of salivary IL-1β throughout the day in healthy young adults. Twelve participants provided saliva samples at various times throughout the day. Salivary IL-1β were assessed using enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Salivary IL-1β levels were highest at 0430 h and lowest at 0000 h and shared a similar diurnal pattern to that of salivary IL-6. Western blot analysis showed that these levels correspond to the mature form of IL-1β. Our findings are important as it established the diurnal pattern of salivary IL-1β is fluctuating normally throughout the day. The findings also open an incredible opportunity for developing research conducted in the field with saliva as the diagnostic tool.


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