1.Arsenic trioxide preconditioning attenuates hepatic ischemia- reperfusion injury in mice: Role of ERK/AKT and autophagy.
Chaoqun WANG ; Hongjun YU ; Shounan LU ; Shanjia KE ; Yanan XU ; Zhigang FENG ; Baolin QIAN ; Miaoyu BAI ; Bing YIN ; Xinglong LI ; Yongliang HUA ; Zhongyu LI ; Dong CHEN ; Bangliang CHEN ; Yongzhi ZHOU ; Shangha PAN ; Yao FU ; Hongchi JIANG ; Dawei WANG ; Yong MA
Chinese Medical Journal 2025;138(22):2993-3003
BACKGROUND:
Arsenic trioxide (ATO) is indicated as a broad-spectrum medicine for a variety of diseases, including cancer and cardiac disease. While the role of ATO in hepatic ischemia/reperfusion injury (HIRI) has not been reported. Thus, the purpose of this study was to identify the effects of ATO on HIRI.
METHODS:
In the present study, we established a 70% hepatic warm I/R injury and partial hepatectomy (30% resection) animal models in vivo and hepatocytes anoxia/reoxygenation (A/R) models in vitro with ATO pretreatment and further assessed liver function by histopathologic changes, enzyme-linked immunosorbent assay, cell counting kit-8, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. Small interfering RNA (siRNA) for extracellular signal-regulated kinase (ERK) 1/2 was transfected to evaluate the role of ERK1/2 pathway during HIRI, followed by ATO pretreatment. The dynamic process of autophagic flux and numbers of autophagosomes were detected by green fluorescent protein-monomeric red fluorescent protein-LC3 (GFP-mRFP-LC3) staining and transmission electron microscopy.
RESULTS:
A low dose of ATO (0.75 μmol/L in vitro and 1 mg/kg in vivo ) significantly reduced tissue necrosis, inflammatory infiltration, and hepatocyte apoptosis during the process of hepatic I/R. Meanwhile, ATO obviously promoted the ability of cell proliferation and liver regeneration. Mechanistically, in vitro studies have shown that nontoxic concentrations of ATO can activate both ERK and phosphoinositide 3-kinase-serine/threonine kinase (PI3K-AKT) pathways and further induce autophagy. The hepatoprotective mechanism of ATO, at least in part, relies on the effects of ATO on the activation of autophagy, which is ERK-dependent.
CONCLUSION
Low, non-toxic doses of ATO can activate ERK/PI3K-AKT pathways and induce ERK-dependent autophagy in hepatocytes, protecting liver against I/R injury and accelerating hepatocyte regeneration after partial hepatectomy.
Animals
;
Arsenic Trioxide
;
Autophagy/physiology*
;
Reperfusion Injury/prevention & control*
;
Mice
;
Male
;
Proto-Oncogene Proteins c-akt/physiology*
;
Arsenicals/therapeutic use*
;
Oxides/therapeutic use*
;
Liver/metabolism*
;
Extracellular Signal-Regulated MAP Kinases/metabolism*
;
Mice, Inbred C57BL
2.SMUG1 promoted the progression of pancreatic cancer via AKT signaling pathway through binding with FOXQ1.
Zijian WU ; Wei WANG ; Jie HUA ; Jingyao ZHANG ; Jiang LIU ; Si SHI ; Bo ZHANG ; Xiaohui WANG ; Xianjun YU ; Jin XU
Chinese Medical Journal 2025;138(20):2640-2656
BACKGROUND:
Pancreatic cancer is a lethal malignancy prone to gemcitabine resistance. The single-strand selective monofunctional uracil DNA glycosylase (SMUG1), which is responsible for initiating base excision repair, has been reported to predict the outcomes of different cancer types. However, the function of SMUG1 in pancreatic cancer is still unclear.
METHODS:
Gene and protein expression of SMUG1 as well as survival outcomes were assessed by bioinformatic analysis and verified in a cohort from Fudan University Shanghai Cancer Center. Subsequently, the effect of SMUG1 on proliferation, cell cycle, and migration abilities of SMUG1 cells were detected in vitro . DNA damage repair, apoptosis, and gemcitabine resistance were also tested. RNA sequencing was performed to determine the differentially expressed genes and signaling pathways, followed by quantitative real-time polymerase chain reaction and Western blotting verification. The cancer-promoting effect of forkhead box Q1 (FOXQ1) and SMUG1 on the ubiquitylation of myelocytomatosis oncogene (c-Myc) was also evaluated. Finally, a xenograft model was established to verify the results.
RESULTS:
SMUG1 was highly expressed in pancreatic tumor tissues and cells, which also predicted a poor prognosis. Downregulation of SMUG1 inhibited the proliferation, G1 to S transition, migration, and DNA damage repair ability against gemcitabine in pancreatic cancer cells. SMUG1 exerted its function by binding with FOXQ1 to activate the Protein Kinase B (AKT)/p21 and p27 pathway. Moreover, SMUG1 also stabilized the c-Myc protein via AKT signaling in pancreatic cancer cells.
CONCLUSIONS
SMUG1 promotes proliferation, migration, gemcitabine resistance, and c-Myc protein stability in pancreatic cancer via protein kinase B signaling through binding with FOXQ1. Furthermore, SMUG1 may be a new potential prognostic and gemcitabine resistance predictor in pancreatic ductal adenocarcinoma.
Humans
;
Pancreatic Neoplasms/pathology*
;
Forkhead Transcription Factors/genetics*
;
Signal Transduction/genetics*
;
Animals
;
Cell Line, Tumor
;
Proto-Oncogene Proteins c-akt/metabolism*
;
Cell Proliferation/physiology*
;
Mice
;
Uracil-DNA Glycosidase/genetics*
;
Female
;
Male
;
Gemcitabine
;
Mice, Nude
;
Apoptosis/physiology*
;
Deoxycytidine/analogs & derivatives*
;
Cell Movement/genetics*
3.Endothelial Cell Integrin α6 Regulates Vascular Remodeling Through the PI3K/Akt-eNOS-VEGFA Axis After Stroke.
Bing-Qiao WANG ; Yang-Ying DUAN ; Mao CHEN ; Yu-Fan MA ; Ru CHEN ; Cheng HUANG ; Fei GAO ; Rui XU ; Chun-Mei DUAN
Neuroscience Bulletin 2025;41(9):1522-1536
The angiogenic response is essential for the repair of ischemic brain tissue. Integrin α6 (Itga6) expression has been shown to increase under hypoxic conditions and is expressed exclusively in vascular structures; however, its role in post-ischemic angiogenesis remains poorly understood. In this study, we demonstrate that mice with endothelial cell-specific knockout of Itga6 exhibit reduced neovascularization, reduced pericyte coverage on microvessels, and accelerated breakdown of microvascular integrity in the peri-infarct area. In vitro, endothelial cells with ITGA6 knockdown display reduced proliferation, migration, and tube-formation. Mechanistically, we demonstrated that ITGA6 regulates post-stroke angiogenesis through the PI3K/Akt-eNOS-VEGFA axis. Importantly, the specific overexpression of Itga6 in endothelial cells significantly enhanced neovascularization and enhanced the integrity of microvessels, leading to improved functional recovery. Our results suggest that endothelial cell Itga6 plays a crucial role in key steps of post-stroke angiogenesis, and may represent a promising therapeutic target for promoting recovery after stroke.
Animals
;
Nitric Oxide Synthase Type III/metabolism*
;
Mice
;
Proto-Oncogene Proteins c-akt/metabolism*
;
Integrin alpha6/genetics*
;
Endothelial Cells/metabolism*
;
Phosphatidylinositol 3-Kinases/metabolism*
;
Stroke/pathology*
;
Vascular Remodeling/physiology*
;
Vascular Endothelial Growth Factor A/metabolism*
;
Mice, Knockout
;
Signal Transduction/physiology*
;
Mice, Inbred C57BL
;
Male
;
Neovascularization, Physiologic/physiology*
4.p53 regulates primordial follicle activation through the mTOR signaling pathway.
Huan LIN ; Tian-He REN ; Yun-Tong TONG ; Gui-Feng WU ; Tuo ZHANG ; Teng-Xiang CHEN ; Guo-Qiang XU
Acta Physiologica Sinica 2023;75(3):339-350
This paper aimed to investigate the role and potential mechanism of p53 on primordial follicle activation. Firstly, the p53 mRNA expression in the ovary of neonatal mice at 3, 5, 7 and 9 days post-partum (dpp) and the subcellular localization of p53 were detected to confirm the expression pattern of p53. Secondly, 2 dpp and 3 dpp ovaries were cultured with p53 inhibitor Pifithrin-μ (PFT-μ, 5 μmol/L) or equal volume of dimethyl sulfoxide for 3 days. The function of p53 in primordial follicle activation was determined by hematoxylin staining and whole ovary follicle counting. The proliferation of cell was detected by immunohistochemistry. The relative mRNA levels and protein levels of the key molecules involved in the classical pathways associated with the growing follicles were examined by immunofluorescence staining, Western blot and real-time PCR, respectively. Finally, rapamycin (RAP) was used to intervene the mTOR signaling pathway, and ovaries were divided into four groups: Control, RAP (1 μmol/L), PFT-μ (5 μmol/L), PFT-μ (5 μmol/L) + RAP (1 μmol/L) groups. The number of follicles in each group was determined by hematoxylin staining and whole ovary follicle counting. The results showed that the expression of p53 mRNA was decreased with the activation of primordial follicles in physiological condition. p53 was expressed in granulosa cells and oocyte cytoplasm of the primordial follicles and growing follicles, and the expression of p53 in the primordial follicles was higher than that in the growing follicles. Inhibition of p53 promoted follicle activation and reduced the primordial follicle reserve. Inhibition of p53 promoted the proliferation of the granulosa cells and oocytes. The mRNA and protein expression levels of key molecules in the PI3K/AKT signaling pathway including AKT, PTEN, and FOXO3a were not significantly changed after PFT-μ treatment, while the expression of RPS6/p-RPS6, the downstream effectors of the mTOR signaling pathway, was upregulated. Inhibition of both p53 and mTOR blocked p53 inhibition-induced primordial follicle activation. Collectively, these findings suggest that p53 may inhibit primordial follicle activation through the mTOR signaling pathway to maintain the primordial follicle reserve.
Female
;
Animals
;
Mice
;
Tumor Suppressor Protein p53/metabolism*
;
Proto-Oncogene Proteins c-akt/metabolism*
;
Phosphatidylinositol 3-Kinases/metabolism*
;
Hematoxylin
;
Signal Transduction/physiology*
;
TOR Serine-Threonine Kinases
;
Sirolimus
;
RNA, Messenger
5.The expression and function of PD-L1 in CD133(+) human liver cancer stem-like cells.
Yu Di BAI ; Mao Lin SHI ; Si Qi LI ; Xiao Li WANG ; Jing Jing PENG ; Dai Jun ZHOU ; Fei Fan SUN ; Hua LI ; Chao WANG ; Min DU ; Tao ZHANG ; Dong LI
Chinese Journal of Oncology 2023;45(2):117-128
Objective: To investigate the expression of programmed death protein-ligand 1 (PD-L1) in liver cancer stem-like cells (LCSLC) and its effect on the characteristics of tumor stem cells and tumor biological function, to explore the upstream signaling pathway regulating PD-L1 expression in LCSLC and the downstream molecular mechanism of PD-L1 regulating stem cell characteristics, also tumor biological functions. Methods: HepG2 was cultured by sphere-formating method to obtain LCSLC. The expressions of CD133 and other stemness markers were detected by flow cytometry, western blot and real-time quantitative polymerase chain reaction (RT-qPCR) were used to detect the expressions of stemness markers and PD-L1. The biological functions of the LCSLC were tested by cell function assays, to confirm that the LCSLC has the characteristics of tumor stem cells. LCSLC was treated with cell signaling pathway inhibitors to identify relevant upstream signaling pathways mediating PD-L1 expression changes. The expression of PD-L1 in LCSLC was down regulated by small interfering RNA (siRNA), the expression of stem cell markers, tumor biological functions of LCSLC, and the changes of cell signaling pathways were detected. Results: Compared with HepG2 cells, the expression rate of CD133 in LCSLC was upregulated [(92.78±6.91)% and (1.40±1.77)%, P<0.001], the expressions of CD133, Nanog, Oct4A and Snail in LCSLC were also higher than those in HepG2 cells (P<0.05), the number of sphere-formating cells increased on day 7 [(395.30±54.05) and (124.70±19.30), P=0.001], cell migration rate increased [(35.41±6.78)% and (10.89±4.34)%, P=0.006], the number of transmembrane cells increased [(75.77±10.85) and (20.00±7.94), P=0.002], the number of cloned cells increased [(120.00±29.51) and (62.67±16.77), P=0.043]. Cell cycle experiments showed that LCSLC had significantly more cells in the G(0)/G(1) phase than those in HepG2 [(54.89±3.27) and (32.36±1.50), P<0.001]. The tumor formation experiment of mice showed that the weight of transplanted tumor in LCSLC group was (1.32±0.17)g, the volume is (1 779.0±200.2) mm(3), were higher than those of HepG2 cell [(0.31±0.06)g and (645.6±154.9)mm(3), P<0.001]. The expression level of PD-L1 protein in LCSLC was 1.88±0.52 and mRNA expression level was 2.53±0.62, both of which were higher than those of HepG2 cells (P<0.05). The expression levels of phosphorylation signal transduction and transcription activation factor 3 (p-STAT3) and p-Akt in LCSLC were higher than those in HepG2 cells (P<0.05). After the expression of p-STAT3 and p-Akt was down-regulated by inhibitor treatment, the expression of PD-L1 was also down-regulated (P<0.05). In contrast, the expression level of phosphorylated extracellular signal-regulated protein kinase 1/2 (p-ERK1/2) in LCSLC was lower than that in HepG2 cells (P<0.01), there was no significant change in PD-L1 expression after down-regulated by inhibitor treatment (P>0.05). After the expression of PD-L1 was knockdown by siRNA, the expressions of CD133, Nanog, Oct4A and Snail in LCSLC were decreased compared with those of siRNA-negative control (NC) group (P<0.05). The number of sphere-formating cells decreased [(45.33±12.01) and (282.00±29.21), P<0.001], the cell migration rate was lower than that in siRNA-NC group [(20.86±2.74)% and (46.73±15.43)%, P=0.046], the number of transmembrane cells decreased [(39.67±1.53) and (102.70±11.59), P=0.001], the number of cloned cells decreased [(57.67±14.57) and (120.70±15.04), P=0.007], the number of cells in G(0)/G(1) phase decreased [(37.68±2.51) and (57.27±0.92), P<0.001], the number of cells in S phase was more than that in siRNA-NC group [(30.78±0.52) and (15.52±0.83), P<0.001]. Tumor formation in mice showed that the tumor weight of shRNA-PD-L1 group was (0.47±0.12)g, the volume is (761.3±221.4)mm(3), were lower than those of shRNA-NC group [(1.57±0.45)g and (1 829.0±218.3)mm(3), P<0.001]. Meanwhile, the expression levels of p-STAT3 and p-Akt in siRNA-PD-L1 group were decreased (P<0.05), while the expression levels of p-ERK1/2 and β-catenin did not change significantly (P>0.05). Conclusion: Elevated PD-L1 expression in CD133(+) LCSLC is crucial to maintain stemness and promotes the tumor biological function of LCSLC.
Humans
;
Animals
;
Mice
;
Proto-Oncogene Proteins c-akt/metabolism*
;
B7-H1 Antigen/metabolism*
;
Ligands
;
Liver Neoplasms/pathology*
;
RNA, Small Interfering/metabolism*
;
Neoplastic Stem Cells/physiology*
;
Cell Line, Tumor
;
Cell Proliferation
6.Sleep deprivation affects sex hormones secretion by regulating the expression of the circadian clock gene in the hypothalamus and pituitary via the PI3K/Akt signaling pathway in pregnant rats.
Acta Physiologica Sinica 2022;74(4):534-540
Sleep deprivation (SD) has many deleterious health effects and occurs in more than 70% of pregnant women. However, the changes in sex hormones and relevant mechanisms after SD have not been well clarified. The aim of the present study was to explore the effects of SD on the secretion of sex hormones and the underlying mechanisms. Twelve pregnant Wistar rats were divided into control (CON, n = 6) and SD (n = 6) groups. Pregnant rats in the SD group were deprived of sleep for 18 h, and allowed free rest for 6 h, and then the above procedures were repeated until delivery. The CON group lived in a 12 h light/dark light cycle environment. Estradiol (E2) and progesterone (P4) levels were detected by enzyme-linked immunosorbent assay (ELISA), and the expression of circadian clock genes, Bmal1, Clock and Per2, in hypothalamus and pituitary gland tissues were evaluated by immunohistochemistry (IHC) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The PI3K and Akt phosphorylation levels in the hypothalamic and pituitary tissues were determined by Western blot. The results showed that, compared with the CON group, the SD group exhibited significantly reduced serum E2 and P4 levels, down-regulated Bmal1, Clock and Per2 expression, as well as decreased phosphorylation levels of PI3K and Akt. But there was no significant difference of the total PI3K and Akt protein expression levels between the two groups. These results suggest that SD might affect the expression of the circadian clock genes in the hypothalamus and pituitary via PI3K/Akt pathway, and subsequently regulate the secretion of sex hormones in the pregnant rats, which hints the important roles of SD-induced changes of serum sex hormone levels in the pregnant rats.
ARNTL Transcription Factors/metabolism*
;
Animals
;
Circadian Clocks/physiology*
;
Circadian Rhythm/genetics*
;
Female
;
Gene Expression Regulation/genetics*
;
Gonadal Steroid Hormones/metabolism*
;
Hypothalamus/metabolism*
;
Phosphatidylinositol 3-Kinases/metabolism*
;
Pituitary Gland/metabolism*
;
Pregnancy
;
Progesterone
;
Proto-Oncogene Proteins c-akt/metabolism*
;
Rats
;
Rats, Wistar
;
Signal Transduction
;
Sleep Deprivation/metabolism*
7.NEK2 promotes the progression of liver cancer by resisting the cellular senescence.
Qian LEI ; Jiliang XIA ; Xiangling FENG ; Jiaojiao GUO ; Guancheng LI ; Wen ZHOU
Journal of Central South University(Medical Sciences) 2022;47(2):153-164
OBJECTIVES:
Liver cancer is the sixth most common malignant tumor in the world. Hepatocellular carcinoma (HCC) accounts for 85%-90% of all patients with liver cancer. It possesses the characteristics of insidious onset, rapid progression, early recurrence, easy drug resistance, and poor prognosis. NIMA related kinase 2 (NEK2) is a cell cycle regulating kinases, which regulates cell cycle in mitosis. Cellular senescence is a complex heterogeneous process, and is a stable form of cell cycle arrest that limits the proliferative potential of cells. This study aims to investigate the relationship between the expression level of NEK2 and the senescence in hepatoma cells, and to explore the effect of NEK2 expression on hepatoma cell senescence and the underlying molecular mechanism.
METHODS:
A total of 581 senescence-relevant genes were obtained from the GenAge website. The gene expression data of tumor tissues of 370 HCC patients were downloaded from the Cancer Genome Atlas database. The co-expression of NEK2 and aging-related genes was analyzed by R-package. KEGG was used to analyze the significant gene enrichment pathway of differentially expressed genes in NEK2 overexpression HEK293. The stable transfected cell lines with overexpression and knockdown of NEK2 were constructed in hepatoma cell line SMMC-7721 and HepG2, and senescence-associated β-galactosidase (SA-β-gal) staining was used to detect senescence, the cell proliferation was detected by CCK-8 method and clone formation experiment, the cell cycle was analyzed by flow cytometry, and the expression of proteins related to p53/p21, p16/Rb, and phosphatase and tensin homolog deleted on chromosome ten (PTEN)/Akt signal transduction pathway was detected by Western blotting.
RESULTS:
There were 320 senescence related genes co-expressed with NEK2. KEGG analysis showed that the senescence signaling pathway was significantly enriched in HEK293 cells with overexpression of NEK2.Compared with SMMC-7721 or HepG2 without knockdown of NEK2, the senescent cells of SMMC-7721 and HepG2 with knockdown of NEK2 were increased, cell proliferation and clone formation were decreased significantly, the percentage of cells in G0/G1 phase was increased, the expression levels of phospho-Akt (p-Akt) and phospho-Rb (p-Rb) protein were decreased significantly, and the expression level of p16 protein was increased significantly (all P<0.05). Compared with SMMC-7721 or HepG2 transfected with blank plasmid, the senescent cells of SMMC-7721 and HepG2 overexpressing NEK2 were decreased, the cell proliferation and clone formation were increased significantly, the percentage of cells in G0/G1 phase were decreased, the expression levels of p-Akt and p-Rb protein were increased significantly, and the expression level of p16 protein was decreased significantly (all P<0.05).
CONCLUSIONS
NEK2 may mediate the anti-aging effect of hepatoma cells through p16/Rb and PTEN/Akt signal transduction pathways, which provides a new theoretical basis for NEK2 to promote the progress of liver cancer and a new idea for the targeting treatment for liver cancer.
Carcinoma, Hepatocellular/pathology*
;
Cell Line, Tumor
;
Cell Proliferation/physiology*
;
Cellular Senescence/genetics*
;
HEK293 Cells
;
Humans
;
Liver Neoplasms/pathology*
;
NIMA-Related Kinases/genetics*
;
Proto-Oncogene Proteins c-akt/metabolism*
8.Salvianolic Acid A Protects Neonatal Cardiomyocytes Against Hypoxia/Reoxygenation-Induced Injury by Preserving Mitochondrial Function and Activating Akt/GSK-3β Signals.
Xue-Li LI ; Ji-Ping FAN ; Jian-Xun LIU ; Li-Na LIANG
Chinese journal of integrative medicine 2019;25(1):23-30
OBJECTIVE:
To investigate the effects of salvianolic acid A (SAA) on cardiomyocyte apoptosis and mitochondrial dysfunction in response to hypoxia/reoxygenation (H/R) injury and to determine whether the Akt signaling pathway might play a role.
METHODS:
An in vitro model of H/R injury was used to study outcomes on primary cultured neonatal rat cardiomyocytes. The cardiomyocytes were treated with 12.5, 25, 50 μg/mL SAA at the beginning of hypoxia and reoxygenation, respectively. Adenosine triphospate (ATP) and reactive oxygen species (ROS) levels were assayed. Cell apoptosis was evaluated by flow cytometry and the expression of cleaved-caspase 3, Bax and Bcl-2 were detected by Western blotting. The effects of SAA on mitochondrial dysfunction were examined by determining the mitochondrial membrane potential (△Ψm) and mitochondrial permeability transition pore (mPTP), followed by the phosphorylation of Akt (p-Akt) and GSK-3β (p-GSK-3β), which were measured by Western blotting.
RESULTS:
SAA significantly preserved ATP levels and reduced ROS production. Importantly, SAA markedly reduced the number of apoptotic cells and decreased cleaved-caspase 3 expression levels, while also reducing the ratio of Bax/Bcl-2. Furthermore, SAA prevented the loss of △Ψm and inhibited the activation of mPTP. Western blotting experiments further revealed that SAA significantly increased the expression of p-Akt and p-GSK-3β, and the increase in p-GSK-3β expression was attenuated after inhibition of the Akt signaling pathway with LY294002.
CONCLUSION
SAA has a protective effect on cardiomyocyte H/R injury; the underlying mechanism may be related to the preservation of mitochondrial function and the activation of the Akt/GSK-3β signaling pathway.
Adenosine Triphosphate
;
analysis
;
Animals
;
Animals, Newborn
;
Caffeic Acids
;
pharmacology
;
Cell Hypoxia
;
Cells, Cultured
;
Glycogen Synthase Kinase 3 beta
;
physiology
;
Lactates
;
pharmacology
;
Mitochondria, Heart
;
drug effects
;
physiology
;
Mitochondrial Membrane Transport Proteins
;
drug effects
;
Myocytes, Cardiac
;
drug effects
;
Proto-Oncogene Proteins c-akt
;
physiology
;
Rats
;
Rats, Sprague-Dawley
;
Reactive Oxygen Species
;
metabolism
;
Signal Transduction
;
physiology
9.The effect of noise exposure on insulin sensitivity in mice may be mediated by the JNK/IRS1 pathway.
Lijie LIU ; Cong FANG ; Jing YANG ; Hongyu ZHANG ; Yi HUANG ; Chuanying XUAN ; Yongfang WANG ; Shengwei LI ; Jun SHA ; Mingming ZHA ; Min GUO
Environmental Health and Preventive Medicine 2018;23(1):6-6
BACKGROUND:
Epidemiological studies have suggested that noise exposure may increase the risk of type 2 diabetes mellitus (T2DM), and experimental studies have demonstrated that noise exposure can induce insulin resistance in rodents. The aim of the present study was to explore noise-induced processes underlying impaired insulin sensitivity in mice.
METHODS:
Male ICR mice were randomly divided into four groups: a control group without noise exposure and three noise groups exposed to white noise at a 95-dB sound pressure level for 4 h/day for 1, 10, or 20 days (N1D, N10D, and N20D, respectively). Systemic insulin sensitivity was evaluated at 1 day, 1 week, and 1 month post-noise exposure (1DPN, 1WPN, and 1MPN) via insulin tolerance tests (ITTs). Several insulin-related processes, including the phosphorylation of Akt, IRS1, and JNK in the animals' skeletal muscles, were examined using standard immunoblots. Biomarkers of inflammation (circulating levels of TNF-α and IL-6) and oxidative stress (SOD and CAT activities and MDA levels in skeletal muscles) were measured via chemical analyses.
RESULTS:
The data obtained in this study showed the following: (1) The impairment of systemic insulin sensitivity was transient in the N1D group but prolonged in the N10D and N20D groups. (2) Noise exposure led to enhanced JNK phosphorylation and IRS1 serine phosphorylation as well as reduced Akt phosphorylation in skeletal muscles in response to exogenous insulin stimulation. (3) Plasma levels of TNF-α and IL-6, CAT activity, and MDA concentrations in skeletal muscles were elevated after 20 days of noise exposure.
CONCLUSIONS
Impaired insulin sensitivity in noise-exposed mice might be mediated by an enhancement of the JNK/IRS1 pathway. Inflammation and oxidative stress might contribute to insulin resistance after chronic noise exposure.
Animals
;
Biomarkers
;
metabolism
;
Inflammation
;
physiopathology
;
Insulin Receptor Substrate Proteins
;
genetics
;
metabolism
;
Insulin Resistance
;
genetics
;
immunology
;
MAP Kinase Signaling System
;
physiology
;
Male
;
Mice
;
Mice, Inbred ICR
;
Mitogen-Activated Protein Kinase 8
;
genetics
;
metabolism
;
Noise
;
adverse effects
;
Oxidative Stress
;
physiology
;
Proto-Oncogene Proteins c-akt
;
genetics
;
metabolism
;
Random Allocation
;
Time Factors
10.Molecular mechanisms of androgens regulating the eNOS expression in rat corpus cavernosum.
Guo-Ping XIE ; Ji-Yi XIA ; Jun LIU ; Rui JIANG
National Journal of Andrology 2017;23(1):11-20
Objective:
To investigate whether androgens can regulate the expression of eNOS in rat corpus cavernosum through AKT3, PIK3CA, CALM, and CAV1 and influence erectile function.
METHODS:
Thirty-six 8-week-old male SD rats were randomly divided into groups A (4-week control), B (6-week control), C (4-week castration), D (6-week castration), E (4-week castration + testosterone replacement), and F (6-week castration + testosterone replacement). Both the testis and epididymis were removed from the rats in groups C, D, E and F, and on the second day after surgery, the animals of groups E and F were subcutaneously injected with testosterone propionate at 3 mg per kg of the body weight qd alt while all the others with isodose oil instead. At 4 weeks (for groups A, C and E) and 6 weeks (for groups B, D and F) after treatment, we detected the maximum intracavernous pressure (ICPmax), the mean carotid arterial pressure (MAP) and their ratio (ICPmax/MAP), measured the level of serum testosterone (T), and determined the expressions of eNOS, P-eNOS, AKT3, PIK3CA, CALM and CAV1 in the corpus cavernosum by Western blot and immunohistochemistry.
RESULTS:
No statistically significant differences were observed in the body weight and MAP among different groups. The serum T level and ICPmax/MAP were remarkably lower in groups C and D than in the other four groups (P<0.01) as well as in groups E and F than in A and B (P<0.05) but exhibited no significant differences either between E and F or between A and B. Immunohistochemistry showed that eNOS and P-eNOS were mainly expressed in the vascular endothelial cell membrane and cavernous vascular lumen, while AKT3, PIK3CA, CALM and CAV1 chiefly in the vascular endothelial cell cytoplasm and membrane, with a few in the smooth muscle cells. Western blot analysis manifested that the expressions of eNOS, P-eNOS, AKT3, PIK3CA, CALM and CAV1 were markedly lower in groups C and D than in A, B, E and F (P<0.01) as well as in D than in C (P<0.05) but those in groups E and F did not showed any significant difference from those in A and B, nor E from F or A from B.
CONCLUSIONS
Androgens can improve erectile function by upregulating the expressions of AKT3, PIK3CA, CALM and CAV1 protein molecules and activating eNOS after its phosphorylation, though the exact molecular mechanisms are yet to be further studied.
Animals
;
Blood Pressure
;
Blotting, Western
;
Caveolin 1
;
metabolism
;
Class I Phosphatidylinositol 3-Kinases
;
metabolism
;
Erectile Dysfunction
;
Hormone Replacement Therapy
;
Male
;
Monomeric Clathrin Assembly Proteins
;
metabolism
;
Myocytes, Smooth Muscle
;
Nitric Oxide Synthase Type III
;
metabolism
;
Orchiectomy
;
Penile Erection
;
physiology
;
Penis
;
enzymology
;
metabolism
;
Proto-Oncogene Proteins c-akt
;
metabolism
;
Random Allocation
;
Rats
;
Rats, Sprague-Dawley
;
Testosterone Propionate
;
administration & dosage

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