Background:The cornea composes the outer surface of the eye and its transparency is required to allow light transmission to the retina.However,because of its position,the cornea is subjected to chemical and mechanical...Background:The cornea composes the outer surface of the eye and its transparency is required to allow light transmission to the retina.However,because of its position,the cornea is subjected to chemical and mechanical injuries that may lead to blindness.Our studies conducted using the human tissue-engineered cornea(hTEC)as a model provided evidence that the cyclic-AMP-response element binding protein(CREB)pathway is repressed during closure of corneal wounds.Based on these results,we hypothesized that closure of corneal wounds can be enhanced by preventing activation of CREB with the pharmacological inhibitor C646.Our goals were to proceed to the pharmacological inhibition of CREB(I)in vitro using the hTECs as a model,and then(II)in vivo using the rabbit as a model.Methods:The self-assembly approach was used to create hTECs,that were then wounded with an 8-mm diameter biopsy punch to create an epithelial defect.The tissues were then incubated with 10μM of C646(n=8).DMSO was used alone as a negative control(n=4).Closure of the wounds was monitored over a period of 5 days.Besides,the cornea of New Zealand white rabbits was debrided with an ethanol 70%solution to create an epithelial defect of 8-mm diameter.Several concentrations of C646(1,10,100μM et 1 mM)were applied as eye drops 3 times a day for up to 7 days.The wounded corneas(n=4 per concentration)were stained with fluorescein and photographed every day.Results:In vitro pharmacological inhibition of CREB with C646 considerably accelerated wound closure of all treated hTECs(4 days)compared to the control group(7 days).Moreover,the in vivo C646 treatment also accelerated wound healing of the corneas compared to the control group.The most effective concentration of C646 tested was the lowest(1μM),as it considerably enhanced the wound healing process.Conclusions:This study demonstrates that wound healing both in vitro and in vivo can be enhanced by preventing activation of CREB using a pharmacological inhibition approach.Most of all,this experiment suggests mediators from the CREB pathway as potential therapeutic targets on which we may influence to alter the wound healing dynamic of the cornea.We believe this study will lead to significant advancements in the clinical field of corneal defects.展开更多
In fasting mammals,the liver is the primary source of glucose production for maintenance of normoglycemia.In this setting,circulating peptide hormones and catecholamines cause hepatic glucose output by stimulating gly...In fasting mammals,the liver is the primary source of glucose production for maintenance of normoglycemia.In this setting,circulating peptide hormones and catecholamines cause hepatic glucose output by stimulating glycogen breakdown as well as de novo glucose production through gluconeogenesis.Fasting gluconeogenesis is regulated by a complex transcriptional cascade culminating in elevated expression of hepatic enzymes that promote gluconeogenesis and glucose export to the blood.The cAMP response element binding protein CREB and its co-activator CRTC2 play crucial roles in signal-dependent transcriptional regulation of gluconeogenesis.Recent work has identified a family of serine/threonine kinases,the salt inducible kinases(SIKs),which are subject to hormonal control and constrain gluconeogenic and lipogenic gene expression in liver.As normal regulation of gluconeogenesis and lipogenesis is disrupted in diabetic states,SIK kinases are poised to serve as therapeutic targets to modulate metabolic disturbances in diabetic patients.The purpose of this review is to 1)describe the identification of CRTCs CREB co-activators and their regulation by SIKs,2)discuss recent progress toward understanding regulation and function of SIKs in metabolism and 3)examine the potential clinical impact of therapeutics that target SIK kinase function.展开更多
文摘Background:The cornea composes the outer surface of the eye and its transparency is required to allow light transmission to the retina.However,because of its position,the cornea is subjected to chemical and mechanical injuries that may lead to blindness.Our studies conducted using the human tissue-engineered cornea(hTEC)as a model provided evidence that the cyclic-AMP-response element binding protein(CREB)pathway is repressed during closure of corneal wounds.Based on these results,we hypothesized that closure of corneal wounds can be enhanced by preventing activation of CREB with the pharmacological inhibitor C646.Our goals were to proceed to the pharmacological inhibition of CREB(I)in vitro using the hTECs as a model,and then(II)in vivo using the rabbit as a model.Methods:The self-assembly approach was used to create hTECs,that were then wounded with an 8-mm diameter biopsy punch to create an epithelial defect.The tissues were then incubated with 10μM of C646(n=8).DMSO was used alone as a negative control(n=4).Closure of the wounds was monitored over a period of 5 days.Besides,the cornea of New Zealand white rabbits was debrided with an ethanol 70%solution to create an epithelial defect of 8-mm diameter.Several concentrations of C646(1,10,100μM et 1 mM)were applied as eye drops 3 times a day for up to 7 days.The wounded corneas(n=4 per concentration)were stained with fluorescein and photographed every day.Results:In vitro pharmacological inhibition of CREB with C646 considerably accelerated wound closure of all treated hTECs(4 days)compared to the control group(7 days).Moreover,the in vivo C646 treatment also accelerated wound healing of the corneas compared to the control group.The most effective concentration of C646 tested was the lowest(1μM),as it considerably enhanced the wound healing process.Conclusions:This study demonstrates that wound healing both in vitro and in vivo can be enhanced by preventing activation of CREB using a pharmacological inhibition approach.Most of all,this experiment suggests mediators from the CREB pathway as potential therapeutic targets on which we may influence to alter the wound healing dynamic of the cornea.We believe this study will lead to significant advancements in the clinical field of corneal defects.
基金supported by grants from the Muscular Dystrophy Association(MDA 68640)the American Heart Association(AHA 09BGIA2261362)the University of Texas Health Science Center,Houston.
文摘In fasting mammals,the liver is the primary source of glucose production for maintenance of normoglycemia.In this setting,circulating peptide hormones and catecholamines cause hepatic glucose output by stimulating glycogen breakdown as well as de novo glucose production through gluconeogenesis.Fasting gluconeogenesis is regulated by a complex transcriptional cascade culminating in elevated expression of hepatic enzymes that promote gluconeogenesis and glucose export to the blood.The cAMP response element binding protein CREB and its co-activator CRTC2 play crucial roles in signal-dependent transcriptional regulation of gluconeogenesis.Recent work has identified a family of serine/threonine kinases,the salt inducible kinases(SIKs),which are subject to hormonal control and constrain gluconeogenic and lipogenic gene expression in liver.As normal regulation of gluconeogenesis and lipogenesis is disrupted in diabetic states,SIK kinases are poised to serve as therapeutic targets to modulate metabolic disturbances in diabetic patients.The purpose of this review is to 1)describe the identification of CRTCs CREB co-activators and their regulation by SIKs,2)discuss recent progress toward understanding regulation and function of SIKs in metabolism and 3)examine the potential clinical impact of therapeutics that target SIK kinase function.