Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and ...Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and regulatory mechanism of tricellulin in the development of salivary gland hypofunction in Sjögren’s syndrome(SS).Employing a multifaceted approach involving patient biopsies,non-obese diabetic(NOD)mice as a SS model,salivary gland acinar cell-specific tricellulin conditional knockout(TricCKO)mice,and IFN-γ-stimulated salivary gland epithelial cells,we investigated the role of tricellulin in SS-related hyposalivation.Our data revealed diminished levels of tricellulin in salivary glands of SS patients.Similarly,NOD mice displayed a reduction in tricellulin expression from the onset of the disease,concomitant with hyposecretion and an increase in salivary albumin content.Consistent with these findings,TricCKO mice exhibited both hyposecretion and leakage of macromolecular tracers when compared to control animals.Mechanistically,the JAK/STAT1/miR-145 axis was identified as mediating the IFN-γ-induced downregulation of tricellulin.Treatment with AT1001,a TJ sealer,ameliorated epithelial barrier dysfunction,restored tricellulin expression,and consequently alleviated hyposalivation in NOD mice.Importantly,treatment with miR-145 antagomir to specifically recover the expression of tricellulin in NOD mice significantly alleviated hyposalivation and macromolecular leakage.Collectively,we identified that tricellulin deficiency in salivary glands contributed to hyposalivation in SS.Our findings highlight tricellulin as a potential therapeutic target for hyposecretion,particularly in the context of reinforcing epithelial barrier function through preventing leakage of macromolecules in salivary glands.展开更多
Autologous submandibular gland（SMG） transplantation has been proved to ameliorate the discomforts in patients with severe keratoconjunctivitis sicca. The transplanted glands underwent a hypofunctional period and the...Autologous submandibular gland（SMG） transplantation has been proved to ameliorate the discomforts in patients with severe keratoconjunctivitis sicca. The transplanted glands underwent a hypofunctional period and then restored secretion spontaneously.This study aims to investigate whether autonomic nerves reinnervate the grafts and contribute to the functional recovery, and further determine the origin of these nerves. Parts of the transplanted SMGs were collected from the epiphora patients, and a rabbit SMG transplantation model was established to fulfill the serial observation on the transplanted glands with time. The results showed that autonomic nerves distributed in the transplanted SMGs and parasympathetic ganglionic cells were observed in the stroma of the glands. Low-dense and unevenly distributed cholinergic axons, severe acinar atrophy and fibrosis were visible in the patients＇ glands 4–6 months post-transplantation, whereas the cholinergic axon density and acinar area were increased with time. The acinar area or the secretory flow rate of the transplanted glands was statistically correlated with the cholinergic axon density in the rabbit model, respectively. Meanwhile, large cholinergic nerve trunks were found to locate in the temporal fascia lower to the gland, and sympathetic plexus concomitant with the arteries was observed both in the adjacent fascia and in the stroma of the glands. In summary, the transplanted SMGs are reinnervated by autonomic nerves and the cholinergic nerves play a role in the morphological and functional restoration of the glands. Moreover, these autonomic nerves might originate from the auriculotemporal nerve and the sympathetic plexus around the supplying arteries.展开更多
Immunoglobulin G4-related sialadenitis(IgG4-RS)is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood.The aim of this study was to explore the role and mechanism of interle...Immunoglobulin G4-related sialadenitis(IgG4-RS)is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood.The aim of this study was to explore the role and mechanism of interleukin-13(IL-13)in the cellular senescence during the progress of IgG4-RS.We found that the expression of IL-13 and IL-13 receptorα1(IL-13Rα1)as well as the number of senescent cells were significantly higher in the submandibular glands(SMGs)of IgG4-RS patients.IL-13 directly induced senescence as shown by the elevated activity of senescence-associatedβ-galactosidase(SA-β-gal),the decreased cell proliferation,and the upregulation of senescence markers(p53 and p16)and senescence-associated secretory phenotype(SASP)factors(IL-1βand IL-6)in SMG-C6 cells.Mechanistically,IL-13 increased the level of phosphorylated signal transducer and activator of transcription 6(p-STAT6)and mitochondrial-reactive oxygen species(mt ROS),while decreased the mitochondrial membrane potential,ATP level,and the expression and activity of superoxide dismutase 2(SOD2).Notably,the IL-13-induced cellular senescence and mitochondrial dysfunction could be inhibited by pretreatment with either STAT6 inhibitor AS1517499 or mitochondria-targeted ROS scavenger Mito TEMPO.Moreover,IL-13 increased the interaction between p-STAT6 and c AMP-response element binding protein(CREB)-binding protein(CBP)and decreased the transcriptional activity of CREB on SOD2.Taken together,our findings revealed a critical role of IL-13 in the induction of salivary gland epithelial cell senescence through the elevated mitochondrial oxidative stress in a STAT6–CREB–SOD2-dependent pathway in IgG4-RS.展开更多
Autophagy is a catabolic process which is involved in the development of many diseases including diabetes mellitus and its complications. Hyposalivation is a common complication of diabetes mellitus, whereas its mecha...Autophagy is a catabolic process which is involved in the development of many diseases including diabetes mellitus and its complications. Hyposalivation is a common complication of diabetes mellitus, whereas its mechanism remains unclear. Here, we observed that the stimulated salivary flow rate of SMG was significantly decreased in db/db mice, a diabetic mice model. The expressions of aquaporin 5(AQP5), a water channel protein, were decreased, whereas the m RNA level of AQP5 was increased in SMGs of both diabetic patients and mice. Under transmission electron microcope, more autophagosomes were detected in diabetic SMGs. Expressions of autophagy related proteins LC3 II, Beclin-1 and ATG5 were increased, meanwhile autophagy substrate p62 was decreased in SMGs of diabetic patients and mice, indicating that autophagy was activated in diabetic SMG.Double immunofluorescence staining showed that the colocalization of AQP5 and LC3 was increased in SMGs of diabetic mice.In cultured SMG-C6 cells, high glucose(HG), but not high osmotic pressure, reduced AQP5 protein expression and induced autophagy. Moreover, inhibition of autophagy by 3-methyladenin, an autophagy inhibitor, or by autophagy-related gene 5 siRNA, decreased HG-induced AQP5 reduction in SMG-C6 cells. Additionally, the expression of p-p85, p-Akt and p-mTOR were decreased in HG-treated SMG-C6 cells. Pretreatment with 740 Y-P, a PI3 K agonist, significantly suppressed HG-induced autophagy and AQP5 degradation. Taken together, these results indicate that autophagy plays a crucial role in AQP5 degradation in diabetic SMG via PI3 K/Akt/mTOR signaling pathway, which contributes to the dysfunction of diabetic SMG. Our study provides a novel mechanism of diabetic hyposalivation.展开更多
Background:Sjögren’s syndrome(SS)is an autoimmune disorder characterized by sicca syndrome and/or systemic manifestations.The treatment is still challenging.This study aimed to explore the therapeutic role and m...Background:Sjögren’s syndrome(SS)is an autoimmune disorder characterized by sicca syndrome and/or systemic manifestations.The treatment is still challenging.This study aimed to explore the therapeutic role and mechanism of exosomes obtained from the supernatant of stem cells derived from human exfoliated deciduous teeth(SHED-exos)in sialadenitis caused by SS.Methods:SHED-exos were administered to the submandibular glands(SMGs)of 14-week-old non-obese diabetic(NOD)mice,an animal model of the clinical phase of SS,by local injection or intraductal infusion.The saliva flow rate was measured after pilocarpine intraperitoneal injection in 21-week-old NOD mice.Protein expression was examined by western blot analysis.Exosomal microRNA(miRNAs)were identified by microarray analysis.Paracellular permeability was evaluated by transepithelial electrical resistance measurement.Results:SHED-exos were injected into the SMG of NOD mice and increased saliva secretion.The injected SHED-exos were taken up by glandular epithelial cells,and further increased paracellular permeability mediated by zonula occluden-1(ZO-1).A total of 180 exosomal miRNAs were identified from SHED-exos,and Kyoto Encyclopedia of Genes and Genomes analysis suggested that the phosphatidylinositol 3 kinase(PI3K)/protein kinase B(Akt)pathway might play an important role.SHED-exos treatment down-regulated phospho-Akt(p-Akt)/Akt,phospho-glycogen synthase kinase 3b(p-GSK-3b)/GSK-3b,and Slug expressions and up-regulated ZO-1 expression in SMGs and SMG-C6 cells.Both the increased ZO-1 expression and paracellular permeability induced by SHED-exos were abolished by insulin-like growth factor 1,a PI3K agonist.Slug bound to the ZO-1 promoter and suppressed its expression.For safer and more effective clinical application,SHED-exos were intraductally infused into the SMGs of NOD mice,and saliva secretion was increased and accompanied by decreased levels of p-Akt/Akt,p-GSK-3b/GSK-3b,and Slug and increased ZO-1 expression.Conclusion:Local application of SHED-exos in SMGs can ameliorate Sjögren syndrome-induced hyposalivation by increasing the paracellular permeability of glandular epithelial cells through Akt/GSK-3b/Slug pathway-mediated ZO-1 expression.展开更多
基金supported by the National Natural Science Foundation of China(grants 31972908,81991500,81991502,and 32030010)Beijing Natural Science Foundation(grant 7202082).
文摘Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and regulatory mechanism of tricellulin in the development of salivary gland hypofunction in Sjögren’s syndrome(SS).Employing a multifaceted approach involving patient biopsies,non-obese diabetic(NOD)mice as a SS model,salivary gland acinar cell-specific tricellulin conditional knockout(TricCKO)mice,and IFN-γ-stimulated salivary gland epithelial cells,we investigated the role of tricellulin in SS-related hyposalivation.Our data revealed diminished levels of tricellulin in salivary glands of SS patients.Similarly,NOD mice displayed a reduction in tricellulin expression from the onset of the disease,concomitant with hyposecretion and an increase in salivary albumin content.Consistent with these findings,TricCKO mice exhibited both hyposecretion and leakage of macromolecular tracers when compared to control animals.Mechanistically,the JAK/STAT1/miR-145 axis was identified as mediating the IFN-γ-induced downregulation of tricellulin.Treatment with AT1001,a TJ sealer,ameliorated epithelial barrier dysfunction,restored tricellulin expression,and consequently alleviated hyposalivation in NOD mice.Importantly,treatment with miR-145 antagomir to specifically recover the expression of tricellulin in NOD mice significantly alleviated hyposalivation and macromolecular leakage.Collectively,we identified that tricellulin deficiency in salivary glands contributed to hyposalivation in SS.Our findings highlight tricellulin as a potential therapeutic target for hyposecretion,particularly in the context of reinforcing epithelial barrier function through preventing leakage of macromolecules in salivary glands.
基金supported by grants from the National Natural Science Foundation of China(No.81671005 and 81470756)
文摘Autologous submandibular gland（SMG） transplantation has been proved to ameliorate the discomforts in patients with severe keratoconjunctivitis sicca. The transplanted glands underwent a hypofunctional period and then restored secretion spontaneously.This study aims to investigate whether autonomic nerves reinnervate the grafts and contribute to the functional recovery, and further determine the origin of these nerves. Parts of the transplanted SMGs were collected from the epiphora patients, and a rabbit SMG transplantation model was established to fulfill the serial observation on the transplanted glands with time. The results showed that autonomic nerves distributed in the transplanted SMGs and parasympathetic ganglionic cells were observed in the stroma of the glands. Low-dense and unevenly distributed cholinergic axons, severe acinar atrophy and fibrosis were visible in the patients＇ glands 4–6 months post-transplantation, whereas the cholinergic axon density and acinar area were increased with time. The acinar area or the secretory flow rate of the transplanted glands was statistically correlated with the cholinergic axon density in the rabbit model, respectively. Meanwhile, large cholinergic nerve trunks were found to locate in the temporal fascia lower to the gland, and sympathetic plexus concomitant with the arteries was observed both in the adjacent fascia and in the stroma of the glands. In summary, the transplanted SMGs are reinnervated by autonomic nerves and the cholinergic nerves play a role in the morphological and functional restoration of the glands. Moreover, these autonomic nerves might originate from the auriculotemporal nerve and the sympathetic plexus around the supplying arteries.
基金supported by the National Natural Science Foundation of China(Nos.81974151,31972908,81991500,and 81991502)。
文摘Immunoglobulin G4-related sialadenitis(IgG4-RS)is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood.The aim of this study was to explore the role and mechanism of interleukin-13(IL-13)in the cellular senescence during the progress of IgG4-RS.We found that the expression of IL-13 and IL-13 receptorα1(IL-13Rα1)as well as the number of senescent cells were significantly higher in the submandibular glands(SMGs)of IgG4-RS patients.IL-13 directly induced senescence as shown by the elevated activity of senescence-associatedβ-galactosidase(SA-β-gal),the decreased cell proliferation,and the upregulation of senescence markers(p53 and p16)and senescence-associated secretory phenotype(SASP)factors(IL-1βand IL-6)in SMG-C6 cells.Mechanistically,IL-13 increased the level of phosphorylated signal transducer and activator of transcription 6(p-STAT6)and mitochondrial-reactive oxygen species(mt ROS),while decreased the mitochondrial membrane potential,ATP level,and the expression and activity of superoxide dismutase 2(SOD2).Notably,the IL-13-induced cellular senescence and mitochondrial dysfunction could be inhibited by pretreatment with either STAT6 inhibitor AS1517499 or mitochondria-targeted ROS scavenger Mito TEMPO.Moreover,IL-13 increased the interaction between p-STAT6 and c AMP-response element binding protein(CREB)-binding protein(CBP)and decreased the transcriptional activity of CREB on SOD2.Taken together,our findings revealed a critical role of IL-13 in the induction of salivary gland epithelial cell senescence through the elevated mitochondrial oxidative stress in a STAT6–CREB–SOD2-dependent pathway in IgG4-RS.
基金supported by National Natural Science Foundation of China (81570993, 81671005)Beijing Natural Science Foundation of China (7162100)
文摘Autophagy is a catabolic process which is involved in the development of many diseases including diabetes mellitus and its complications. Hyposalivation is a common complication of diabetes mellitus, whereas its mechanism remains unclear. Here, we observed that the stimulated salivary flow rate of SMG was significantly decreased in db/db mice, a diabetic mice model. The expressions of aquaporin 5(AQP5), a water channel protein, were decreased, whereas the m RNA level of AQP5 was increased in SMGs of both diabetic patients and mice. Under transmission electron microcope, more autophagosomes were detected in diabetic SMGs. Expressions of autophagy related proteins LC3 II, Beclin-1 and ATG5 were increased, meanwhile autophagy substrate p62 was decreased in SMGs of diabetic patients and mice, indicating that autophagy was activated in diabetic SMG.Double immunofluorescence staining showed that the colocalization of AQP5 and LC3 was increased in SMGs of diabetic mice.In cultured SMG-C6 cells, high glucose(HG), but not high osmotic pressure, reduced AQP5 protein expression and induced autophagy. Moreover, inhibition of autophagy by 3-methyladenin, an autophagy inhibitor, or by autophagy-related gene 5 siRNA, decreased HG-induced AQP5 reduction in SMG-C6 cells. Additionally, the expression of p-p85, p-Akt and p-mTOR were decreased in HG-treated SMG-C6 cells. Pretreatment with 740 Y-P, a PI3 K agonist, significantly suppressed HG-induced autophagy and AQP5 degradation. Taken together, these results indicate that autophagy plays a crucial role in AQP5 degradation in diabetic SMG via PI3 K/Akt/mTOR signaling pathway, which contributes to the dysfunction of diabetic SMG. Our study provides a novel mechanism of diabetic hyposalivation.
基金supported by grants from the National Natural Science Foundation of China(Nos.81974151 and 81771088)Peking University-Tason Stomatology Development Fund.
文摘Background:Sjögren’s syndrome(SS)is an autoimmune disorder characterized by sicca syndrome and/or systemic manifestations.The treatment is still challenging.This study aimed to explore the therapeutic role and mechanism of exosomes obtained from the supernatant of stem cells derived from human exfoliated deciduous teeth(SHED-exos)in sialadenitis caused by SS.Methods:SHED-exos were administered to the submandibular glands(SMGs)of 14-week-old non-obese diabetic(NOD)mice,an animal model of the clinical phase of SS,by local injection or intraductal infusion.The saliva flow rate was measured after pilocarpine intraperitoneal injection in 21-week-old NOD mice.Protein expression was examined by western blot analysis.Exosomal microRNA(miRNAs)were identified by microarray analysis.Paracellular permeability was evaluated by transepithelial electrical resistance measurement.Results:SHED-exos were injected into the SMG of NOD mice and increased saliva secretion.The injected SHED-exos were taken up by glandular epithelial cells,and further increased paracellular permeability mediated by zonula occluden-1(ZO-1).A total of 180 exosomal miRNAs were identified from SHED-exos,and Kyoto Encyclopedia of Genes and Genomes analysis suggested that the phosphatidylinositol 3 kinase(PI3K)/protein kinase B(Akt)pathway might play an important role.SHED-exos treatment down-regulated phospho-Akt(p-Akt)/Akt,phospho-glycogen synthase kinase 3b(p-GSK-3b)/GSK-3b,and Slug expressions and up-regulated ZO-1 expression in SMGs and SMG-C6 cells.Both the increased ZO-1 expression and paracellular permeability induced by SHED-exos were abolished by insulin-like growth factor 1,a PI3K agonist.Slug bound to the ZO-1 promoter and suppressed its expression.For safer and more effective clinical application,SHED-exos were intraductally infused into the SMGs of NOD mice,and saliva secretion was increased and accompanied by decreased levels of p-Akt/Akt,p-GSK-3b/GSK-3b,and Slug and increased ZO-1 expression.Conclusion:Local application of SHED-exos in SMGs can ameliorate Sjögren syndrome-induced hyposalivation by increasing the paracellular permeability of glandular epithelial cells through Akt/GSK-3b/Slug pathway-mediated ZO-1 expression.
