scholarly journals Sirt-1 Regulates Physiological Process and Exerts Protective Effects against Oxidative Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lei Liu ◽  
Guangyuan Xia ◽  
Peifan Li ◽  
Yiming Wang ◽  
Qian Zhao
Keyword(s):  
Oxidative Stress ◽  
Transcriptional Activity ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Therapeutic Drug ◽  
Mrna Levels ◽  
P53 Expression ◽  
Protein Levels ◽  
Gene Assay

Background. Recent studies suggest a correlation between the reduced Sirt-1 expression with Alzheimer’s diseases (AD) and depression, respectively, suggesting a possible pathogenic role of the altered Sirt-1 expression in neuronal degenerative diseases, such as AD and depression. However, the molecular mechanisms underlying how Sirt-1 reduction impairs neuronal functions remain unknown. Methods. We used the SK-N-SH neuroblastoma cells to study the role of Sirt-1 expression on physiological roles in neuronal cells. Gain of Sirt-1 was achieved by transiently transfecting Sirt-1 expression plasmid. Sirt-1-specific shRNA was used to elucidate the role of Sirt-1 loss of function. CCK-8 (Cell Counting Kit-8) assay and flow cytometry were used to evaluate cell proliferation. Semiquantitative western blotting was used to detect relative protein levels. A further luciferase reporter gene assay was employed to examine the effect of Sirt-1 expression on the transcriptional activity of p53. RT-qPCR was used to determine the mRNA levels of p21, Bax, and Bcl-2, which were the downstream target genes of p53. Results. Sirt-1 suppressed the p53 downstream gene p21 transcription, while shRNA-mediated Sirt-1 knockdown resulted in a significant increase in p21 expression, implying a possibility that Sirt-1 promotes neuron proliferation through suppressing p53 transcriptional activity. The mRNA and protein levels of p53 were not affected by the altered Sirt-1 expression, suggesting that Sirt-1 regulates the transcriptional regulatory activity of p53 rather than p53 expression. Indeed, we further confirmed that Sirt-1 appeared to inhibit p53 transcriptional activity by attenuating its acetylation and resulted in a decrease of p53’s binding to the p21 promoter. Overexpressed Sirt-1 scavenged reactive oxygen species (ROS) production in SK-N-SH with H2O2. Knockdown of Sirt-1 presented opposite effect; the addition of EX527 (Sirt-1 inhibitor) increased ROS accumulation. Conclusions. Oxidative stress induces Sirt-1 in neuron cells, and Sirt-1 promotes proliferation in SK-N-SH cells, which protects them from oxidative stress-induced cell death, potentially via suppressing the transcriptional activity of p53. These results provide a molecular explanation underlying how the reduced Sirt-1 potentially causes the AD and depression-related diseases, supporting the idea that Sirt-1 can possibly be used as a diagnostic biomarker and/or therapeutic drug target for the AD and depression-related diseases.

scholarly journals The Role of the FOXO1/β2-AR/p-NF-κB p65 Pathway in the Development of Endometrial Stromal Cells in Pregnant Mice under Restraint Stress

2021 ◽  
Vol 22 (3) ◽  
pp. 1478
Author(s):  
Jiayin Lu ◽  
Yaoxing Chen ◽  
Zixu Wang ◽  
Jing Cao ◽  
Yulan Dong
Keyword(s):  
Oxidative Stress ◽  
Stromal Cells ◽  
Restraint Stress ◽  
Target Genes ◽  
Mrna Levels ◽  
Endometrial Stromal Cells ◽  
Protein Levels ◽  
Pregnant Mice

Restraint stress causes various maternal diseases during pregnancy. β2-Adrenergic receptor (β2-AR) and Forkhead transcription factor class O 1 (FOXO1) are critical factors not only in stress, but also in reproduction. However, the role of FOXO1 in restraint stress, causing changes in the β2-AR pathway in pregnant mice, has been unclear. The aim of this research was to investigate the β2-AR pathway of restraint stress and its impact on the oxidative stress of the maternal uterus. In the study, maternal mice were treated with restraint stress by being restrained in a transparent and ventilated device before sacrifice on Pregnancy Day 5 (P5), Pregnancy Day 10 (P10), Pregnancy Day 15 (P15), and Pregnancy Day 20 (P20) as well as on Non-Pregnancy Day 5 (NP5). Restraint stress augmented blood corticosterone (CORT), norepinephrine (NE), and blood glucose levels, while oestradiol (E2) levels decreased. Moreover, restraint stress increased the mRNA levels of the FOXO family, β2-AR, and even the protein levels of FOXO1 and β2-AR in the uterus and ovaries. Furthermore, restraint stress increased uterine oxidative stress level. In vitro, the protein levels of FOXO1 were also obviously increased when β2-AR was activated in endometrial stromal cells (ESCs). In addition, phosphorylated-nuclear factor kappa-B p65 (p-NF-κB p65) and its target genes decreased significantly when FOXO1 was inhibited. Overall, it can be said that the β2-AR/FOXO1/p-NF-κB p65 pathway was activated when pregnant mice were under restraint stress. This study provides a scientific basis for the origin of psychological stress in pregnant women.

microRNA-422a Inhibits DCC Expression in a Manner Dependent on SNP rs12607853

2020 ◽  
Vol 160 (2) ◽  
pp. 63-71
Author(s):  
Yunxiao Li ◽  
Xugang Shi ◽  
Xintong Cai ◽  
Yongsheng Zhu ◽  
Yuanyuan Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Opioid Addiction ◽  
Heroin Addiction ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Protein Levels ◽  
Gene Assay ◽  
New Biomarkers ◽  
And Function

DCC netrin 1 receptor (DCC) affects the structure and function of the dopamine circuitry, which in turn affects the susceptibility to developing addiction. In a previous study, we found that single nucleotide polymorphism (SNP) rs12607853 in the 3′ untranslated region (3′-UTR) of DCC was significantly associated with heroin addiction. In the current study, we first used bioinformatics prediction to identify the DCC rs12607853 C allele as a potential hsa-miR-422a and hsa-miR-378c target site. We then used vector construction and dual-luciferase reporter assays to investigate the targeting relationship of DCC rs12607853 with hsa-miR-422a and hsa-miR-378c. The dual-luciferase reporter gene assay confirmed that the C allele of rs12607853 in combination with hsa-miR-422a led to repressed dual-luciferase gene expression. Moreover, gene expression assays disclosed that hsa-miR-422a inhibited DCC expression at both the mRNA and protein levels. We also found that morphine inhibited the expression of hsa-miR-422a but increased the expression of DCC mRNA, and this change in the expression of hsa-miR-422a could not be reversed by naloxone, which suggested that the role of DCC in opioid addiction might be regulated by hsa-miR-422a. In summary, this study improves our understanding of the role of hsa-miR-422a and identifies the genetic basis of rs12607853, which might contribute to the discovery of new biomarkers or therapeutic targets for opioid addiction.

scholarly journals Circ_0124644 Serves as a ceRNA for miR-590-3p to Promote Hypoxia-Induced Cardiomyocytes Injury via Regulating SOX4

2021 ◽  
Vol 12 ◽  
Author(s):  
Juan Tan ◽  
Weinan Pan ◽  
Huilin Chen ◽  
Yafang Du ◽  
Peiyong Jiang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Circular Rna ◽  
Suppressive Effect ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Protein Levels ◽  
Stress Markers ◽  
Transcription Factor 4

Circular RNA (circRNA) is an important factor for regulating the progression of many cardiovascular diseases, including acute myocardial infarction (AMI). However, the role of circ_0124644 in AMI progression remains unclear. Hypoxia was used to induce cardiomyocytes injury. The expression of circ_0124644, microRNA (miR)-590-3p, and SRY-box transcription factor 4 (SOX4) mRNA was measured by qRT-PCR. Cell counting kit 8 (CCK8) assay and flow cytometry were utilized to detect cell viability, cell cycle progression, and apoptosis. The protein levels of apoptosis markers and SOX4 were determined by western blot (WB) analysis, and the levels of oxidative stress markers were assessed using commercial Assay Kits. Dual-luciferase reporter assay, RIP assay, and RNA pull-down assay were employed to confirm the interaction between miR-590-3p and circ_0124644 or SOX4. Circ_0124644 was upregulated in AMI patients and hypoxia-induced cardiomyocytes. Hypoxia could inhibit cardiomyocytes viability, cell cycle process, and promote apoptosis and oxidative stress, while silencing circ_0124644 could alleviate hypoxia-induced cardiomyocytes injury. In terms of mechanism, circ_0124644 could target miR-590-3p. MiR-590-3p overexpression could relieve hypoxia-induced cardiomyocytes injury. Also, the suppressive effect of circ_0124644 knockdown on hypoxia-induced cardiomyocytes injury could be reversed by miR-590-3p inhibitor. Moreover, SOX4 was found to be a target of miR-590-3p, and its overexpression also could reverse the regulation of miR-590-3p on hypoxia-induced cardiomyocytes injury. Circ_0124644 silencing could alleviate hypoxia-induced cardiomyocytes injury by regulating the miR-590-3p/SOX4 axis, suggesting that it might be a target for alleviating AMI.

scholarly journals H19/miR-194/E2F3 regulating loop promotes gastric cancer growth and metastasis

2020 ◽  
Author(s):  
Wanxiang Qin ◽  
Ying Shi ◽  
Dan Zhu ◽  
Yaohua Chen ◽  
Yuping Li ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Lines ◽  
Competitive Binding ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Mrna Levels ◽  
Ags Cells ◽  
Qrt Pcr ◽  
Gene Assay

Abstract Background: Gastric cancer (GC) is one of the most frequent malignant digestive tumors and second fatal cancer. This study was to investigate whether lncRNA-H19 can regulate E2F3 expression through competitive binding to microRNA-194 (miR-194), thus regulating GC growth and metastasis. Methods: H19, miR-194, and E2F3 expression levels in GC tissues and cell lines were investigated using quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR). Meanwhile, the mRNA levels of H19 and E2F3 in gastric cancer tissues were also analyzed through the GEPIA web tool. The binding condition of miR-194 with H19 and E2F3 was investigated using a dual-luciferase reporter gene assay. The regulatory effects of H19 on proliferative, migratory, and invasive abilities of AGS cells and SGC-7901 cells were detected by transwell assay and cell counting kit-8 (CCK-8). Genes involved in proliferation, migration, and invasion (PCNA, Vimentin, and N-cadherin) were determined using QRT-PCR and western blot. The regulatory interaction between H19 and miR-194, miR-194, and E2F3 were investigated using rescue experiments. Results: The results revealed that H19 was highly expressed in GC tissues and cell lines than those of controls. Downregulated H19 decreased the proliferation, migration, and invasion of AGS cells and SGC-7901 cells. H19 was demonstrated that being the molecular sponge of miR-194 in regulating the growth of the GC cells. The level of E2F3 expression was also found significantly higher in GC tissues and cell lines than those of controls. And then, the mimics of miR-194 inhibited the expression of E2F3 in the GC cells. CCK-8 assay showed decreased proliferative ability induced by miR-194 mimics were reversed by E2F3 overexpression. Transwell assays showed decreased migratory and invasive ability induced by miR-194 mimics were reversed by E2F3 overexpression. Conclusions: This study demonstrates that H19 promotes GC growth and metastasis by regulating E2F3 via competitive binding to miRNA-194.

scholarly journals GATA1-induced upregulation of LINC01503 promotes carboplatin resistance in ovarian carcinoma by upregulating PD-L1 via sponging miR-766-5p

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yao Li ◽  
Yan Zhai ◽  
Yuxuan Chen
Keyword(s):  
Ovarian Carcinoma ◽  
Inhibitory Concentration ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Invasive Ability ◽  
Protein Levels ◽  
Reverse Transcription Quantitative Pcr ◽  
Non Coding Rnas ◽  
Dual Luciferase Reporter Assay

Abstract Background Ovarian Carcinoma (OCa) is a high-mortality malignancy derived from female reproductive system. Increasing evidence has identified long non-coding RNAs (lncRNAs) as important regulators in OCa chemoresistance. In this study, we intended to explore the role of LINC01503 in OCa resistance to carboplatin (CBP). Methods Gene expression was measured by reverse transcription-quantitative PCR (RT-qPCR) in OCa cells. Western blot was adopted to detect protein levels of GATA1, PD-L1, E-cadherin, N-cadherin, Vimentin, Bcl-2, Bax, cleaved caspase-3. To assess the effects of LINC01503 on the resistance of OCa cells to CBP, Cell Counting Kit-8 (CCK-8), colony formation, Transwell, and flow cytometry experiments were performed to evaluate half-maximal inhibitory concentration (IC50), cell viability, migrative and invasive ability, as well as cell apoptosis. Dual-luciferase reporter assay was employed to assess the associations between the genes. Results LINC01503 was upregulated in CBP-resistant OCa cells. LINC01503 knockdown reduced CBP resistance in OCa cells. Besides, GATA-binding protein 1 (GATA1) activated LINC01503 transcription in CBP-resistant OCa cells. MiR-766-5p was lowly expressed in CBP-resistant cells and confirmed as a target for LINC01503. In addition, miR-766-5p overexpression increased CBP sensitivity in OCa cells. PD-L1 was verified as the target of miR-766-5p. Besides, LINC01503 upregulated PD-L1 level by regulating miR-766-5p. Furthermore, rescue experiments showed that PD-L1 overexpression abrogated the inhibited impacts of blocking LINC01503 on CBP resistance in OCa cells. Conclusion GATA1-induced LINC01503 expedited CBP resistance in OCa cells via the miR-766-5p/PD-L1 axis, providing a new target for improving the efficacy of OCa chemotherapy. Graphical Abstract

Bioengineered microRNA-1291 effects on pancreatic cancer cell proliferation and xenograft tumor growth.

2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 307-307
Author(s):  
Mei-Juan Tu ◽  
Zhijian Duan ◽  
Qianyu Zhang ◽  
Jing-Xin Qiu ◽  
Frank J Gonzalez ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Tumor Growth ◽  
Therapeutic Potential ◽  
Xenograft Model ◽  
Luciferase Reporter ◽  
Mrna Levels ◽  
Luciferase Reporter Gene ◽  
Protein Levels ◽  
Gene Assay

307 Background: MicroRNAs (miR) have proved to be vital regulators in the control of tumor progression. Our recent studies have revealed miR-1291 is downregulated in patient pancreatic cancer (PC) specimens and re-introduction of miR-1291 suppresses tumorigenesis of PC cells. We have developed a novel ncRNA bioengineering technology to produce a miR-1291 prodrug. In this study, we aimed to assess the effectiveness of this miR-1291 prodrug as a monotherapy, as well as in combination with chemotherapy, for treatment of PC. Methods: Sensitivity of PC cells to miR-1291 prodrug alone, gemcitabine plus nab-paclitaxel (Gem-nP) alone, and their combination was evaluated by CellTiter-Glo assay. Mature miR-1291 and ARID3B mRNA levels were determined by quantitative real-time PCR (q-PCR) assay. A luciferase reporter gene assay was used to validate interaction between miR-1291 and ARID3B 3’UTR. Target protein expression was examined by Western blot and immunofluorescence analyses. PANC-1 and PC patient-derived xenograft (PDX) mouse models were established and used to assess anti-tumor effects of miR-1291 monotherapy and combination therapy with Gem-nP. Results: Cytotoxicity assays showed that miR-1291 prodrug enhanced the sensitivity of PANC-1 and AsPC-1 cells to Gem-nP. Luciferase assays confirmed ARID3B as a target for miR-1291 as predicted by computational analysis. qPCR analysis demonstrated that miR-1291 prodrug was readily processed to mature miR-1291 and subsequently upregulated ARID3B mRNA levels. miR-1291 prodrug also elevated the protein levels of ARID3B. Co-administration of miR-1291 prodrug and Gem-nP increased caspase-3/7 and γH2AX levels in PC cells, compared to miR-1291 or Gem-nP treatment alone. In addition, systemic administration of in vivo-jet PEI formulated miR-1291 prodrug suppressed tumor growth in both a PANC-1 xenograft model and three PDX models, and largely enhanced the efficacy of Gem-nP. All treatments were well tolerated in mice in vivo. Conclusions: Our bioengineered miR-1291 prodrug has therapeutic potential as a monotherapy but also can act as a sensitizing agent to chemotherapy. This novel treatment approach should be further explored for PC.

scholarly journals H19/miR-194/E2F3 regulating loop promotes gastric cancer growth and metastasis

2020 ◽  
Author(s):  
Wanxiang Qin ◽  
Ying Shi ◽  
Dan Zhu ◽  
Yaohua Chen ◽  
Yuping Li ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Lines ◽  
Competitive Binding ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Mrna Levels ◽  
Ags Cells ◽  
Qrt Pcr ◽  
Gene Assay

Abstract Background Gastric cancer (GC) is one of the most frequent malignant digestive tumors and second fatal cancer. This study was to investigate whether lncRNA-H19 can regulate E2F3 expression through competitive binding to microRNA-194 (miR-194), thus regulating GC growth and metastasis. Methods H19, miR-194, and E2F3 expression levels in GC tissues and cell lines were investigated using quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR). Meanwhile, the mRNA levels of H19 and E2F3 in gastric cancer tissues were also analyzed through the GEPIA web tool. The binding condition of miR-194 with H19 and E2F3 was investigated using a dual-luciferase reporter gene assay. The regulatory effects of H19 on proliferative, migratory, and invasive abilities of AGS cells and SGC-7901 cells were detected by transwell assay and cell counting kit-8 (CCK-8). Genes involved in proliferation, migration, and invasion (PCNA, Vimentin, and N-cadherin) were determined using QRT-PCR and western blot. The regulatory interaction between H19 and miR-194, miR-194, and E2F3 were investigated using rescue experiments. Results The results revealed that H19 was highly expressed in GC tissues and cell lines than those of controls. Downregulated H19 decreased the proliferation, migration, and invasion of AGS cells and SGC-7901 cells. H19 was demonstrated that being the molecular sponge of miR-194 in regulating the growth of the GC cells. The level of E2F3 expression was also found significantly higher in GC tissues and cell lines than those of controls. And then, the mimics of miR-194 inhibited the expression of E2F3 in the GC cells. CCK-8 assay showed decreased proliferative ability induced by miR-194 mimics were reversed by E2F3 overexpression. Transwell assays showed decreased migratory and invasive ability induced by miR-194 mimics were reversed by E2F3 overexpression. Conclusions This study demonstrates that H19 promotes GC growth and metastasis by regulating E2F3 via competitive binding to miRNA-194.

Plantamajoside Ameliorates Inflammatory Response of Chondrocytes via Regulating NF-κB/NLRP3 Inflammasome Pathway

2021 ◽  
Vol 11 (5) ◽  
pp. 997-1002
Author(s):  
Chi Zhang ◽  
Yuanhe Wang ◽  
Chuan Hu ◽  
Kang Sun ◽  
Dingzhu Yu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Inflammatory Response ◽  
Cell Viability ◽  
Nlrp3 Inflammasome ◽  
Underlying Mechanism ◽  
Cell Counting ◽  
Enzyme Linked Immunosorbent Assay ◽  
Apoptotic Cells ◽  
Protein Levels

The damage of articular cartilage in osteoarthritis involves the oxidative stress and inflammation. The aim of the present study was to explore the role of plantamajoside (PM) in chondrocytes and elucidate the underlying mechanism. The cell viability following treatment with PM or lipopolysac-charide (LPS) was assessed by cell counting kit-8 (CCK-8). Enzyme-Linked Immunosorbent Assay (ELISA) was supplied to determine the levels of pro-inflammatory cytokines. Moreover, the oxidative stress-related markers were evaluated via assay kits. TUNEL assay was employed to stain the apoptotic cells. The components of nuclear factor-κB (NF-κB) pathway and NLRP3 inflammasome were estimated by western blot analysis. LPS-insulted cell viability of ATDC5 was restored by PM. PM alleviated the inflammatory response and oxidative stress of ATDC5 cells induced by LPS. Furthermore, it was found that the apoptotic cells were reduced following PM treatment. The protein levels of NF-κB, IκB kinase β (IKKβ) and NLRP3 inflammasome were decreased by PM. These results suggested that PM protected the ATDC5 cells from LPS stimulation, alleviated the inflammatory response may through regulating the NF-κB and NLRP3 inflammasome.

scholarly journals Upregulation of Extracellular Vesicles-Encapsulated miR-132 Released From Mesenchymal Stem Cells Attenuates Ischemic Neuronal Injury by Inhibiting Smad2/c-jun Pathway via Acvr2b Suppression

2021 ◽  
Vol 8 ◽  
Author(s):  
Bin Feng ◽  
Lei Meng ◽  
Liming Luan ◽  
Zhihao Fang ◽  
Peng Zhao ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Extracellular Vesicles ◽  
Neuronal Cell ◽  
Neuronal Injury ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Gene Assay ◽  
Ischemic Neuronal Injury

Ischemic cerebrovascular disease is a significant and common public health issue worldwide. The emerging roles of mesenchymal stem cells (MSCs)-derived extracellular vesicles (EVs) in ischemic neuronal injury continue to be investigated. The current study aimed to investigate the role of EV-derived miR-132 from MSCs in ischemic neuronal injury. EVs were initially isolated from bone MSCs (BMSCs) and subsequently evaluated. A middle cerebral artery occlusion (MCAO) mouse model was constructed with the neurological function evaluated through a series of neurological scores, a pole test, and a foot fault test. Histopathological changes, neuron viability, and apoptosis, as well as cerebral infarction, were detected by hematoxylin and eosin (HE) staining and 2,3,5-triphenyltetrazolium hydrochloride (TTC) staining. The targeting relationship between microRNA (miR)-132 and Activin receptor type IIB (Acvr2b) was further confirmed based on dual-luciferase reporter gene assay results. Loss- and gain-of-function assays were conducted to elucidate the role of miR-132, EV-derived miR-132, Acvr2b, and Smad2 in oxygen-glucose deprivation (OGD)-treated neurons, and in mice models. Neuronal cell viability and apoptosis were evaluated via Cell Counting kit-8 (CCK-8) and flow cytometry. Our results indicated that Acvr2b was highly expressed, while miR-132 was poorly expressed in the MCAO mice and OGD-treated neurons. Acvr2b silencing or upregulation of miR-132 led to an elevation in neuronal activity, decreased neuronal apoptosis, reduced expression of Bax, and cleaved-caspase 3, as well as increased Bcl-2 expression. Acvr2b expression was targeted and inhibited by miR-132. EV-derived Acvr2b promoted activation of phosphorylated-Smad2 (p-Smad2)/c-jun signaling pathway, ultimately inducing neuronal injury. Our study provides evidence demonstrating that the overexpression of c-jun inhibits the protective role of MSCs-derived EV-miR-132 in neuronal injury. Upregulation of EV-derived miR-132 released from MSCs attenuates ischemic neuronal injury by inhibiting Smad2/c-jun pathways via the suppression of Acvr2b.

scholarly journals Oxidative stress induces cell death partially by decreasing both mRNA and protein levels of nicotinamide phosphoribosyltransferase in PC12 cells

2020 ◽  
Author(s):  
Cuiyan Zhou ◽  
Weihai Ying
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Pc12 Cells ◽  
Mrna Levels ◽  
Salvage Pathway ◽  
Nicotinamide Phosphoribosyltransferase ◽  
Protein Levels ◽  
Pathological Conditions ◽  
Important Enzyme

AbstractNumerous studies have indicated critical roles of NAD+ deficiency in both aging and multiple major diseases. It is critical to investigate the mechanisms underlying the NAD+ deficiency under the pathological conditions. It has been reported that there was a decreased level of Nicotinamide phosphoribosyltransferase (Nampt) – an important enzyme in the salvage pathway of NAD+ synthesis – under certain pathological conditions, while the mechanisms underlying the Nampt decrease require investigation. In this study we used differentiated PC12 cells as a cellular model to investigate the effects of oxidative stress on both the mRNA and protein levels of Nampt, as well as the role of this effect in oxidative stress-induced cell death: First, Nampt plays significant roles in both the NAD+ synthesis and survival of the cells under basal conditions; second, H2O2 produced significant decreases in both the mRNA levels and the protein levels of Nampt; and third, H2O2 induced cell death partially by producing the decreases in the mRNA and protein levels of Nampt, since the Nampt inhibitor or the Nampt activator significantly exacerbated or attenuated the H2O2-induced cell death, respectively. Collectively, our study has indicated that oxidative stress can decrease both the mRNA and protein levels of Nampt, which has indicated a novel mechanism underlying the NAD+ deficiency in aging and under multiple pathological conditions. Our study has also indicated that the decreased Nampt levels contribute to the H2O2-induced cell death, suggesting a new mechanism underlying oxidative cell death.

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