-
[show abstract]
[hide abstract]
ABSTRACT: AIMS: Nucleolin plays important roles in a variety of cellular processes. In this study, we aimed to investigate the role of nucleolin in cardiac ischemia/reperfusion injury.Methods and ResultsWe investigated the expression pattern of nucleolin in hearts subjected to ischemia/reperfusion (I/R), or neonatal rat cardiomyocytes subjected to hypoxia/reoxygenation (H/R). We found that nucleolin expression was significantly down regulated and the cleaved protein was present, both in vivo and in vitro. Gene transfection and RNA interference approaches were employed in cardiomyocytes to investigate the function of nucleolin. Overexpression of nucleolin was cytoprotective, whereas nucleolin ablation enhanced both hypoxia- and H2O2-induced cardiomyocyte death. Furthermore, transgenic mice with cardiac-specific overexpression of nucleolin were resistant to I/R injury as indicated by decreased cellular necrosis and decreased infarct size. The cardio-protective roles of nucleolin in cardiomyocytes, are attributable to the interaction of nucleolin with the mRNA of Hsp32, resulting in an increase of Hsp32 mRNA stability, and subsequent upregulation of Hsp32 expression. The selective Hsp32 inhibitor, ZnPP, abrograted the cardiac protection mediated by nucleolin. CONCLUSIONS: This study has demonstrated that nucleolin is involved in the regulation of I/R-induced cardiac injury and dysfunction via regulation of Hsp32, and may be a novel therapeutic target for ischemic heart diseases.
Cardiovascular research 04/2013; · 5.80 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor family of ligand-inducible transcription factors. Our previous study has shown that in human umbilical vein endothelial cells PPARbeta initiates a protective mechanism that limits the extent of damage due to H2O2-induced injury. Although fibroblasts are one of the main cell types involved in wound repair, the role of PPARbeta in the fibroblast response to heat injury has not been investigated. Thus, in this study, we examined possible protective role of PPARbeta in fibroblasts from heat injury. We developed a novel dermal fibroblast heat injury model to characterize the mechanisms of the heat injury healing response that involved PPARbeta. The specific PPARbeta ligand GW0742, a PPARbeta activator and a short hairpin RNA (shRNA) plasmid against PPARbeta were used to reveal the action mechanism of PPARbeta in heat injury-induced fibroblast changes in morphology and increased proliferation. In response to heat injury (52 degrees C for 30 s), fibroblast activation of PPARbeta increased 1.56-fold. Administration of GW0742 significantly induced a protective effect on heat injury-induced fibroblasts by minimizing the structural damage and increasing the cell proliferation response. Likewise, inhibition of PPARbeta using shRNA exacerbated the damage by inhibiting the de novo synthesis of PPARbeta. These results indicated that heat injury enhanced PPARbeta expression and PPARbeta protected fibroblast structure and proliferation.
Indian journal of biochemistry & biophysics 08/2012; 49(4):219-27. · 1.14 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Denatured dermis is a part of the dermis in deep burn wound and has the ability to restore normal morphology and function. Skin grafting with the preservation of denatured dermis is a new kind of surgical procedure and has reported satisfactory clinical effects, such as lessened scar contracture and a better restoration of the appearance and function. However, the underlying mechanism of the recovery of denatured dermal function remains unclear. MicroRNAs (miRNAs) are a new class of regulatory noncoding single-stranded RNAs, which play a key role in normal development and physiology, as well as in disease development. This study analysed the profile of miRNAs in denatured dermis from patients and further investigated the possible roles of miRNAs played in the functional recovery of denatured dermis by prediction of the potential target genes of differentially expressed miRNAs.
The denatured dermis and paired normal skin were collected and analysed by miRNA array. The miRNA profiling results were validated by real-time reverse transcriptase polymerase chain reaction (RT-PCR), and bioinformatics' analysis was employed to further predict the miRNA targets.
A total of 66 miRNAs were differentially expressed in denatured dermis compared with those in normal skin, among which 34 were down-regulated while 32 are up-regulated. The most significantly up-regulated miRNA was miR-663, and the most significantly down-regulated one was miR-203. Differentially expressed miRNAs were predicted to be related with several signalling pathways in wound healing.
The differential miRNA expression identified in this study supplies experimental basis for further understanding the mechanisms of functional recovery of the denatured dermis.
Burns: journal of the International Society for Burn Injuries 02/2012; 38(4):534-40. · 1.95 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We have previously shown that heat shock protein 70 (HSP70) markedly inhibits H(2)O(2)-induced apoptosis in mouse C2C12 myogenic cells by reducing the release of Smac. However, the molecular mechanism by which HSP70 interferes with Smac release during oxidative stress-induced apoptosis is not understood. In the current study, we showed that HSP70 increased the stability of Bcl-2 during oxidative stress. An antisense phosphorothioate oligonucleotide against Bcl-2 caused selective inhibition of Bcl-2 protein expression induced by HSP70 and significantly attenuated HSP70-mediated cell protection against H(2)O(2)-induced release of Smac and apoptosis. Taken together, our results indicate that there are important relationships among HSP70, Bcl-2, release of Smac, and induction of apoptosis by oxidative stress.
Cell Stress and Chaperones 10/2010; 16(2):143-52. · 3.01 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although heat shock protein 70 (Hsp70) has been shown to markedly inhibit H(2)O(2)-induced apoptosis in C2C12 cells, and nucleolin/C23 has also been implicated in apoptosis, the relationship of these two molecules is still largely unknown. The aim of the current study was to investigate the potential involvement of nucleolin/C23 in the antiapoptotic mechanism of Hsp70. We found that primary cultures of neonatal rat cardiomyocytes underwent apoptosis upon H(2)O(2) treatment, and in these cells nucleolin/C23 protein was highly unstable and had a half-life of less than 4 h. However, transfection with Hsp70 greatly stabilized nucleolin/C23 and also protected the cells from H(2)O(2)-induced apoptosis. When nucleolin/C23 was knocked down with an antisense oligomer, H(2)O(2)-induced apoptosis became more severe, even in Hsp70-overexpressed cells, demonstrating an essential role of nucleolin/C23 in the antiapoptotic effects of Hsp70. Similar results were obtained by both nuclear morphology observation and caspase-3 activity assay. Therefore, these data provide evidence that nucleolin/C23 is an essential downstream effecter of Hsp70 in the protection of cardiomyocytes against oxidative stress-induced apoptosis.
FEBS Journal 02/2010; 277(3):642-52. · 3.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Nucleolin plays important roles in chromatin structure, rDNA transcription, rRNA maturation, nucleocytoplasmic transport, and ribosome assembly. Although it has been shown to be anti-apoptotic, the underlying mechanisms remain unclear. In the current study, we first examined endogenous nucleolin expression in response to oxidative stress-induced apoptosis in human umbilical vascular endothelial cells (HUVECs). Flow cytometry and caspase activity assays showed that H(2)O(2) treatment caused apoptosis of the cells; reverse-transcription polymerase chain reaction and Western blotting revealed the downregulation of nucleolin expression and increased protein cleavage during this process. Overexpression of nucleolin protein by transfecting cells with the full-length nucleolin cDNA inhibited apoptosis, but nucleolin deficiency brought about by transfection with antisense oligonucleotide increased apoptosis of HUVECs. Concurrently, the expression of the apoptotic protein gene Bax was also downregulated following nucleolin overexpression. All these results indicate an important negative regulatory role for nucleolin in the apoptosis of endothelial cells, likely involving the Bax pathway.
Cell Stress and Chaperones 09/2009; 15(3):249-57. · 3.01 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Hydrogen peroxide (H(2)O(2)) is a well known oxidative stress inducer causing apoptosis of many cells. Previously, we have shown that heat shock pretreatment blocked the release of the second mitochondria-derived activator of caspase (Smac) to the cytosol and inhibited apoptosis of C2C12 myoblast cells in response to H(2)O(2). The present study aimed to elucidate the underlying mechanism by over-expressing a major stress-inducible protein, heat shock protein (HSP) 70, and characterizing the resulting cellular changes. We demonstrate that HSP70 over-expression markedly inhibited the release of Smac and prevented the activation of caspases-9 and -3 and apoptosis in C2C12 cells under H(2)O(2) treatment. However, no direct interaction between HSP70 and Smac was observed by co-immunoprecipitation. Mutational analysis demonstrated that the ATP-binding domain of HSP70, rather than the peptide-binding domain, was essential for these observed HSP functions. Taken together, our results provide evidence supporting the role of HSP70 in the protection of C2C12 cells from H(2)O(2)-induced and Smac-promoted apoptosis by preventing the release of Smac from mitochondria, thereby inhibiting activation of caspases-9 and -3. This mechanism of HSP70 action is dependent on its ATP-binding domain but independent of its interaction with Smac protein.
FEBS Journal 06/2009; 276(9):2615-24. · 3.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Repetitive stress has been shown to up-regulate antioxidant defense and increase survival after subsequent oxidative injury. The up-regulation of antioxidant defense has been identified as an underlying cause of the apoptosis-inhibitory effects exerted by repetitive stress. However, it remains unclear what the important signaling mechanisms are by which cells preexposed to low-grade stress deal with apoptosis-inducing stress. In this study, we repetitively stressed human umbilical vein endothelial cells (HUVECs) through multiple exposures to a low dose (30 microM) of H(2)O(2) in culture for 4 weeks. We then examined the effects of repetitive stress on PPAR-beta expression and activity as well as the role of PPAR-beta in the protective potency of repetitive stress. Our results show that repetitive stress enhances PPAR-beta expression and activity, thereby inhibiting oxidative stress-induced apoptosis. Further, PPAR-beta-directed antisense oligonucleotides reduced the PPAR-beta protein content, enhanced the H(2)O(2)-mediated apoptosis, and ablated the protective effect of repetitive low-grade H(2)O(2) stress. The specific PPAR-beta agonist L-165041 significantly potentiated the apoptosis induced by H(2)O(2) (p<0.05) and increased the protective effect of repetitive stress. These findings indicate that repetitive low-grade H(2)O(2) stress protects HUVECs from subsequent oxidative stress-induced apoptosis by enhancing PPAR-beta expression and activity.
Free radical biology & medicine 12/2008; 46(5):555-63. · 5.42 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Peroxisome proliferator-activated receptor beta (PPAR-beta) is a ligand activated transcription factor belonging to the nuclear receptor superfamily. Recent evidence suggests that PPAR-beta has clearly defined roles in skin wound healing, inflammation and cell proliferation. However, little is known about the role of PPAR-beta in oxidative stress-induced apoptosis in human umbilical vein endothelial cells (HUVECs). In this study, a specific PPAR-beta ligand, L-165041, and antisense phosphorothioate oligodeoxynucleotides (asODNs) against PPAR-beta were used to reveal the role of PPAR-beta in oxidative stress-induced apoptosis. The results showed that H(2)O(2) at 0.5mM resulted in a marked increase of apoptosis and a significant down-regulation of PPAR-beta expression and activation in HUVECs. Moreover, L-165041 significantly inhibited H(2)O(2)-induced apoptosis (P<0.05) and asODNs against PPAR-beta markedly inhibited the de novo synthesis of PPAR-beta, which was accompanied by enhanced apoptosis induced by H(2)O(2) (P<0.05). These data demonstrated that H(2)O(2) down-regulated the expression and activation of PPAR-beta, which played important roles in H(2)O(2)-induced apoptosis in HUVECs.
Atherosclerosis 09/2008; 204(2):353-8. · 3.79 Impact Factor
-
Pengfei Liang,
Bimei Jiang,
Xinghua Yang,
Xianzhong Xiao,
Xu Huang,
Jianhong Long,
Pihong Zhang,
Minghua Zhang,
Muzhang Xiao,
Tinghong Xie,
Xiaoyuan Huang
[show abstract]
[hide abstract]
ABSTRACT: Epidermal growth factor (EGF) has been shown to be a potent mitogen for epidermal cells both in vitro and in vivo, thus contributing to the development of an organism. It has recently become clear that peroxisome proliferator-activated receptor-beta/delta (PPARbeta/delta) expression and activation is involved in the cell proliferation. However, little is known about the role of PPARbeta/delta in EGF-induced proliferation of HaCaT keratinocytes. In this study, HaCaT cells were cultured in the presence and absence of EGF and we identified that EGF induced an increase of PPARbeta/delta mRNA and protein level expression in time-dependent and dose-dependent manner, and AG1487, an EGF receptor (EGFR) special inhibitor, caused attenuation of PPARbeta/delta protein expression. Electrophoretic mobility shift assay (EMSA) revealed that EGF significantly increased PPARbeta/delta binding activity in HaCaT keratinocytes. Antisense phosphorothioate oligonucleotides (asODNs) against PPARbeta/delta caused selectively inhibition of PPARbeta/delta protein content induced by EGF and significantly attenuated EGF-mediated cell proliferation. Treatment of the cells with L165041, a specific synthetic ligand for PPARbeta/delta, significantly enhanced EGF-mediated cell proliferation. Finally, c-Jun ablation inhibited PPARbeta/delta up-regulation induced by EGF, and chromatin immunoprecipitation (ChIP) showed that c-Jun bound to the PPARbeta/delta promoter and the binding increased in EGF-stimulated cells. These results demonstrate that EGF induces PPARbeta/delta expression in a c-Jun-dependent manner and PPARbeta/delta plays a vital role in EGF-stimulated proliferation of HaCaT cells.
Experimental Cell Research 07/2008; 314(17):3142-51. · 3.58 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Starch, one of the most commonly used polysaccharides, has been adopted for the first time as morphology-directing agent to the electrochemical synthesis of polypyrrole (PPy) nanowires on various electrodes.
Chemical Communications 07/2007; · 6.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Established methods for kidney dialysis do not work for liver failure because kidney dialysis removes only water-soluble toxins, while the liver normally removes albumin-bound toxins. In the present study, a polysulfone dialysis membrane with a -OH reactive group was prepared by hydrolyzing the chloromethylated polysulfone membrane, and the bovine serum albumin molecules were fixed into the membrane with 1,1'-carbonyldiimidazole activation. The content of albumin of the albumin-fixed membrane was 121.3 mg (g membrane)(-1). The albumin-fixed dialysis membranes were used to remove protein-bound toxins, bilirubin, from the bilirubin-albumin solution. The transfer rate of bilirubin of the albumin-fixed membrane was obviously higher compared to the normal dialysis membrane. The clearance of bilirubin with the albumin-fixed membrane was 49.8%. The albumin-fixed membrane can easily be regenerated by the bovine serum albumin and NaOH solution. Regeneration of the membrane suggested good mechanical and chemical stability, as well as good clearance of bilirubin. In addition, the effects of membrane thickness and bilirubin initial concentration on the removal of bilirubin were discussed.
Biomedical Materials 10/2006; 1(3):170-4. · 2.16 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Repetitive stress has been shown to up-regulate antioxidant defense and increase survival after subsequent oxidative injury. The up-regulation of antioxidant defense has been identified as an underlying cause of the apoptosis-inhibitory effects exerted by repetitive stress. However, it remains unclear what the important signaling mechanisms are by which cells preexposed to low-grade stress deal with apoptosis-inducing stress. In this study, we repetitively stressed human umbilical vein endothelial cells (HUVECs) through multiple exposures to a low dose (30 μM) of H2O2 in culture for 4 weeks. We then examined the effects of repetitive stress on PPAR-β expression and activity as well as the role of PPAR-β in the protective potency of repetitive stress. Our results show that repetitive stress enhances PPAR-β expression and activity, thereby inhibiting oxidative stress-induced apoptosis. Further, PPAR-β-directed antisense oligonucleotides reduced the PPAR-β protein content, enhanced the H2O2-mediated apoptosis, and ablated the protective effect of repetitive low-grade H2O2 stress. The specific PPAR-β agonist L-165041 significantly potentiated the apoptosis induced by H2O2 (p < 0.05) and increased the protective effect of repetitive stress. These findings indicate that repetitive low-grade H2O2 stress protects HUVECs from subsequent oxidative stress-induced apoptosis by enhancing PPAR-β expression and activity.
Free Radical Biology and Medicine.
-
[show abstract]
[hide abstract]
ABSTRACT: Epidermal growth factor (EGF) plays an important role in epithelial cell proliferation and apoptosis. Our recent studies found that EGF-attenuated tumor necrosis factor-alpha induced HaCaT keratinocyte apoptosis, and this effect was accompanied by up-regulation of the expression of peroxisome proliferator-activated receptor beta (PPARbeta). However, little is known about whether PPARbeta is functionally involved in the inhibition of keratinocyte apoptosis by EGF. Here, we showed that EGF up-regulated the DNA-binding and transcriptional regulation activities of PPARbeta. Antisense phosphorothioate oligonucleotides against PPARbeta markedly inhibited de novo synthesis of PPARbeta and attenuated the protective effect of EGF on tumor necrosis factor-alpha-induced apoptosis. L165041, a specific PPARbeta ligand, significantly enhanced the transcriptional regulation activity of PPARbeta and increased the protective effect of EGF. These results suggest a molecular mechanism by which EGF protects HaCaT keratinocytes against apoptosis in a PPARbeta-dependent manner.
Wound Repair and Regeneration 16(5):691-8. · 2.91 Impact Factor
