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Xin Cong,
Yan Zhang,
Ning-Yan Yang,
Jing Li,
Chong Ding,
Qian-Wen Ding,
Yun-Chao Su,
Mei Mei,
Xiao-Hong Guo,
Li-Ling Wu,
Guang-Yan Yu
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ABSTRACT: Occludin plays an important role in maintaining tight junction barrier function in many types of epithelia. We previously reported that activation of transient receptor potential vanilloid subtype 1 (TRPV1) in rabbit submandibular gland promoted salivary secretion partly via an increase in paracellular permeability. Here we explored the role of occludin in TRPV1-modulated paracellular permeability in a rat submandibular gland cell line SMG-C6. Both TRPV1 and occludin were expressed in SMG-C6 cells, and capsaicin induced redistribution of occludin, but not claudin-3, claudin-4, or E-cadherin, from cell membrane into cytoplasm. Capsaicin also decreased transepithelial electrical resistance (TER) and increased the trypan blue and FITC-dextran flux. Capsazepine (CPZ), a TRPV1 antagonist, inhibited the capsaicin-induced occludin redistribution and TER decrease. Moreover, occludin knockdown by shRNA suppressed while occludin re-expression restored the TER response to capsaicin. Mechanistically, TRPV1 activation increased ERK1/2 and MLC2 phosphorylation. PD98059, an ERK1/2 kinase inhibitor, abolished the capsaicin-induced MLC2 phosphorylation, while ML-7, an MLC2 kinase inhibitor, did not affect ERK1/2 phosphorylation, suggesting that ERK1/2 was the upstream signaling molecule of MLC2. Capsaicin also induced F-actin reorganization, which was abolished by CPZ, PD98059, and ML-7, indicating that TRPV1 activation altered F-actin organization in an ERK1/2- and MLC2-dependent manner. Furthermore, either PD98059 or ML-7 could abolish the capsaicin-induced TER response and occludin redistribution, while knockdown of ERK1/2 further confirmed that the TRPV1-modulated paracellular permeability was ERK1/2-dependent. Taken together, these results identified a critical role of occludin in submandibular epithelial cells, and more importantly, demonstrated that occludin was required to mediate TRPV1-modulated paracellular permeability.
Journal of Cell Science 01/2013; · 6.11 Impact Factor
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Xiao-Hong Guo,
Jin-Yu Wang,
Yan Gao,
Min Gao,
Guang-Yan Yu,
Ruo-Lan Xiang,
Li Li,
Ning-Yan Yang, Xin Cong,
Xiao-Yan Xu,
Sheng-Lin Li,
Xin Peng,
Li-Ling Wu
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ABSTRACT: Circulating adiponectin levels are inversely associated with risk of various obesity-related cancers. However, the effect of adiponectin on carcinogenesis and progression of tongue squamous cell carcinoma (TSCC) remains unknown. We measured serum adiponectin levels in 59 patients with TSCC and 50 healthy controls. Expression of adiponectin and its receptors in paired tumor and paracancerous specimens were determined by immunohistochemical staining (n = 37) and western blot (n = 30), respectively. Serum adiponectin level was lower in patients than controls (5.0 ± 2.4 vs 8.4 ± 3.5 μg/mL, P < 0.01), and was inversely associated with histological grade and lymph node metastasis but not tumor size. Local adiponectin levels in tumor tissue gradually decreased as tumor-node-metastasis (TNM) stage increased, while the expression of adiponectin receptors was unchanged. Additionally, serum adiponectin levels in the TSCC patients without metabolic and cardiovascular diseases, or without smoking and drinking habits, were still lower than controls. Furthermore, adiponectin inhibited the migration, but not proliferation, of SCC15 cells in vitro. These results indicate that decreased adiponectin level is associated with risk of TSCC. Hypoadiponectinemia might be used as a biomarker to predict an aggressive phenotype of TSCC.
Cancer Science 11/2012; · 3.33 Impact Factor
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Sheng li ke xue jin zhan [Progress in physiology] 06/2012; 43(3):193-7.
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ABSTRACT: BACKGROUND: Ischemic preconditioning (IPC) can reduce ischemia/reperfusion (I/R) injury in multiple organs and species. However, the effect of IPC on transplanted submandibular glands remains unknown. We explored the protection of IPC in transplanted submandibular glands in the rabbit and the underlying mechanism. METHODS: IPC was performed by clamping the lingual artery for 10 min, with 10 min of reperfusion before transplantation. Male rabbits were randomly divided into control, transplantation, and IPC groups (n = 6 each). Saliva secretion, oxidative stress, pro-inflammatory cytokine levels, and apoptosis-related protein levels were determined at 1, 12, and 24 h after reperfusion. RESULTS: Salivary flow was significantly increased at 12 h and decreased at 24 h in the transplanted glands. IPC treatment prevented the reduced saliva secretion at 24 h after reperfusion (P < 0.01). The mRNA levels of tumor necrosis factor-α, interleukin-1β, and reactive oxygen species, as well as malondialodehyde (MDA) and myeloperoxidase activity, were significantly increased and superoxide dismutase activity was decreased in the transplanted glands. However, these changes were all attenuated with IPC treatment (all P < 0.05). Also, acinar cell apoptosis and Bax protein expression were decreased and Bcl-2 protein expression was increased in the IPC-treated glands at 1 and 12 h after reperfusion (all P < 0.05). CONCLUSIONS: IPC protects the secretory function of transplanted submandibular gland in the rabbit by reducing the inflammatory response, attenuating oxidative stress, and an anti-apoptosis process.
Journal of Surgical Research 03/2012; · 2.25 Impact Factor
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Xin Cong,
Yan Zhang,
Liang Shi,
Ning-Yan Yang,
Chong Ding,
Jing Li,
Qian-Wen Ding,
Yun-Chao Su,
Ruo-Lan Xiang,
Li-Ling Wu,
Guang-Yan Yu
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ABSTRACT: Tight junction (TJ) is an important structure that regulates material transport through the paracellular pathway across the epithelium, but its significance in salivary physiology and pathogenesis of salivary dysfunctional diseases is not fully understood. We previously demonstrated that a functional transient receptor potential vanilloid subtype 1 (TRPV1) expresses in submandibular gland (SMG). However, association of TRPV1-induced saliva secretion with TJ remains unknown. Here we explored the effect of TRPV1 activation on expression and function of TJ of rabbit SMG in vitro and in vivo. RT-PCR and western blot analysis revealed that capsaicin upregulated expression of zonula occludin-1 (ZO-1), claudin (Cldn)-3, and -11, but not Cldn-1, -2, -4, -5, and -7 in cultured SMG cells. Capsaicin also increased the entering of 4 kDa FITC-dextran into the acinar lumen, induced redistribution of cytoskeleton F-actin under confocal microscope, and these effects were abolished by preincubation of capsazepine, a TRPV1 antagonist, indicating that activation of TRPV1 increases expression and permeability of TJ in SMG. Additionally, in a hyposecretory model induced by rabbit SMG transplantation, the expression of ZO-1, Cldn-3, and -11 was decreased, whereas other TJs remained unaltered. The structure of TJ was impaired and the width of apical TJs was reduced under transmission electron microscope, concomitant with diminished immunofluorescence of F-actin in peri-apicolateral region, indicating impaired TJ expression and decreased paracellular permeability in the transplanted SMG. Moreover, topical capsaicin cream increased secretion, decreased TJ structural injury, reversed TJ expression levels, and protected F-actin morphology from disarrangement in transplanted SMGs. These data provide the first evidence to demonstrate that TJ components, particularly ZO-1, Cldn-3, and -11 have important roles in secretion of SMG under both physiological and pathophysiological conditions. The injury in TJ integrity was involved in the hypofunctional SMGs, and TRPV1 might be a potential target to improve saliva secretion through modulating expression and function of TJs.
Laboratory Investigation 03/2012; 92(5):753-68. · 3.64 Impact Factor
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ABSTRACT: Submandibular gland autotransplantation is effective for treating severe dry eye syndrome. However, more than 40% of patients show epiphora within 3-6 months after treatment. The mechanism underlying the hypersecretion in epiphora remains to be elucidated for developing novel interventions. Since salivary gland secretion is dependent on a variety of proteins, we analyzed the changes in protein expression in transplanted glands of epiphora patients with 2-D gel electrophoresis and electrospray ionization quadrupole/time-of-flight mass spectrometry and evaluated their possible roles in epiphora. There were 23 proteins that showed altered expression in the glands of epiphora patients, 15 being up-expressed and 8 being down-expressed. The expression of secretory proteins was decreased in these glands, including alpha-amylase, cystatin S, SA, and SN. In contrast, cytoskeletal proteins were all up-regulated, including actin and vimentin. Immunofluorescence revealed that the intensity ratio of F-actin in apical and lateral cytoplasm to total F-actin in acini was decreased in the glands of epiphora patients. Carbachol stimulation induced a similar redistribution of F-actin in the control glands. Phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) was increased in both carbachol-stimulated and epiphora glands. Preincubation of submandibular glands with ERK1/2 inhibitors PD98059 or U0126 inhibited carbachol-induced F-actin redistribution. These results indicated that differentially expressed proteins participated in the hypersecretion of transplanted submandibular glands and the redistribution of F-actin might be involved in this hypersecretion in an ERK1/2-dependent manner.
Journal of Proteome Research 03/2011; 10(5):2206-15. · 5.11 Impact Factor
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ABSTRACT: Hyposecretion occurs in most patients early after submandibular gland autotransplantation for severe keratoconjunctivitis sicca. Endogenous transient receptor potential vanilloid subtype 1 (TRPV1) has been recently demonstrated in rabbit submandibular glands, and activation of TRPV1 by capsaicin increases secretion in isolated glands, but the TRPV1-mediated secretory mechanism remains to be elucidated. The purpose of this study was to verify whether activation of TRPV1 by capsaicin could improve the secretion of transplanted gland and its underlying mechanism. The salivary flow of the transplanted glands was significantly decreased, and the mRNA and protein levels of TRPV1 and aquaporin 5 (AQP5) were downregulated in the transplanted glands. Topical capsaicin cream increased secretion and upregulated levels of TRPV1 and AQP5 in transplanted glands. Moreover, in cultured submandibular gland cells, capsaicin increased the mRNA expression of AQP5 and led to redistribution of AQP5 from the cytoplasm to the plasma membrane via TRPV1 activation. Capsaicin enhanced the phosphorylation of extracellular signal-regulated kinase (ERK). Preincubation of cells with PD98059, an inhibitor of ERK kinase, suppressed the capsaicin-induced mRNA expression of AQP5. In summary, the capsaicin-induced secretory mechanism involved activation of TRPV1 and upregulation of AQP5 in an ERK-dependent manner and promoted the redistribution of AQP5 in submandibular gland cells. Activation of TRPV1 may provide a new therapeutic strategy to improve submandibular gland hypofunction.
AJP Gastrointestinal and Liver Physiology 04/2010; 299(1):G54-62. · 3.43 Impact Factor
