Dataset Information

Long-term agonist exposure induces upregulation of beta 3-adrenergic receptor expression via multiple cAMP response elements.

ABSTRACT: During continuous stimulation by agonist, beta 1- and beta 2-adrenergic receptors (ARs) undergo processes that lead to decreases in receptor expression. This receptor down-regulation serves to limit the cellular cAMP response during chronic agonist exposure. In the recently described third subtype of the beta AR, denoted beta 3AR, we found four potential cAMP response elements in the 5' flanking region, suggesting that expression of this receptor might be positively regulated by agonists. These elements were cloned into the vector pA10CAT2, which contains a chloramphenicol acetyltransferase reporter gene, and transiently expressed in VERO cells. Three of these elements, TGACTCCA, TGAGGTCT, and CGAGGTCA (located 518, 622, and 1125 bases upstream of the beta 3AR coding block, respectively) were found to increase transcription of the chloramphenicol acetyltransferase gene in response to cAMP analogues and agents that increase intracellular cAMP. 3T3-F442A cells, when differentiated into the adipocyte phenotype by insulin, expressed beta 3AR, and nuclear runoff studies from such cells confirmed cAMP enhancement of beta 3AR mRNA transcription. In these cells, beta 3AR mRNA increased in response to exposure to the beta 3AR agonist isoproterenol and remained elevated during exposures of up to 24-30 hr. During prolonged exposure to agonist, no downregulation of beta 3AR expression in 3T3-F442A cells occurred. Indeed, beta 3AR expression increased during agonist exposure to approximately 165% of basal expression. In marked contrast, beta 1AR expression declined by approximately 70% in response to chronic agonist exposure. These studies reveal a subtype-specific prolonged transcriptional regulation of a beta AR gene by the end product of its signal transduction pathway. Thus, the beta 3AR undergoes a paradoxical increase in receptor expression during chronic agonist exposure.

SUBMITTER: Thomas RF

PROVIDER: S-EPMC49108 | biostudies-other | 1992 May

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Long-term agonist exposure induces upregulation of beta 3-adrenergic receptor expression via multiple cAMP response elements.

Thomas R F RF Holt B D BD Schwinn D A DA Liggett S B SB

Proceedings of the National Academy of Sciences of the United States of America 19920501 10

During continuous stimulation by agonist, beta 1- and beta 2-adrenergic receptors (ARs) undergo processes that lead to decreases in receptor expression. This receptor down-regulation serves to limit the cellular cAMP response during chronic agonist exposure. In the recently described third subtype of the beta AR, denoted beta 3AR, we found four potential cAMP response elements in the 5' flanking region, suggesting that expression of this receptor might be positively regulated by agonists. These ...[more]

PMID: 1374904

Shared Molecules

Only show the datasets with similarity scores above: 0.5

Threshold

0.5

Similar Datasets

Project description:Purpose: Features of cellular senescence have been described in diabetic retinal vasculature. The aim of this study was to investigate how the high glucose microenvironment impacts on the senescence program of retinal endothelial cells. Methods: Human retinal microvascular endothelial cells were cultured under control and high glucose conditions of 5 mM and 25 mM D-glucose, respectively. Isomeric l-glucose was used as the osmotic control. Cells were counted using CASY technology until they reached their Hayflick limit. Senescence-associated β-Galactosidase was used to identify senescent cells. Endothelial cell functionality was evaluated by the clonogenic, 3D tube formation, and barrier formation assays. Cell metabolism was characterized using the Seahorse Bioanalyzer. Gene expression analysis was performed by bulk RNA sequencing. Retinal tissues from db/db and db/+ mice were evaluated for the presence of senescent cells. Publicly available scRNA-sequencing data for retinas from Akimba and control mice was used for gene set enrichment analysis. Results: Long term exposure to 25 mM D-Glucose accelerated the establishment of cellular senescence in human retinal endothelial cells when compared to 5 mM D-glucose and osmotic controls. This was shown from 4 weeks, by a significant slower growth, higher percentages of cells positive for senescence-associated β-galactosidase, an increase in cell size, and lower expression of pRb and HMGB2. These senescence features were associated with decreased clonogenic capacity, diminished tubulogenicity, and impaired barrier function. Long term high glucose-cultured cells exhibited diminished glycolysis, with lower protein expression of GLUT1, GLUT3, and PFKFB3. Transcriptomic analysis, after 4 weeks of culture, identified downregulation of ALDOC, PFKL, and TPI1, in cells cultured with 25 mM D-glucose when compared to controls. The retina from db/db mice showed a significant increase in acellular capillaries associated with a significant decrease in vascular density in the intermediate and deep retinal plexuses, when compared to db/+ mice. Senescent endothelial cells within the db/db retinal vasculature were identified by senescence-associated β-galactosidase staining. Analysis of single cell transcriptomics data for the Akimba mouse retina highlighted an enrichment of senescence and senescence-associated secretory phenotype gene signatures when compared to control mice. Conclusion: A diabetic-like microenvironment of 25 mM D-glucose was sufficient to accelerate the establishment of cellular senescence in human retinal microvascular endothelial cells.

Dataset Information

Long-term agonist exposure induces upregulation of beta 3-adrenergic receptor expression via multiple cAMP response elements.

Publications

Long-term agonist exposure induces upregulation of beta 3-adrenergic receptor expression via multiple cAMP response elements.

Shared Molecules

Only show the datasets with similarity scores above: 0.5

Threshold

0.5

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets