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Adrenergic sensitivity of cultured murine trisomy 16 cells
Abstract:
Murine trisomy 16 (Ts16) has been proposed as a model to study Down's syndrome (DS), because mouse chromosome 16 carries several genes homologous to loci on the human chromosome 21. A characteristic of DS is an increased sensitivity to adrenergic ligands. We have tested the sensitivity of murine Ts16 fibroblasts and embryonic cells to epinephrine and isoproterenol. A 2-4-fold reduction in the accumulated cyclic AMP (cAMP) was observed in response to these beta 1-adrenergic ligands. Since these cells also accumulated a 2-4-fold reduced amount of cAMP in response to prostaglandin E1, the data suggest that a change in the adenylcyclase of these cells exists which is not seen in cells derived from DS individuals. Therefore, murine Ts16 cells do not appear to constitute an appropriate model to study the altered adrenergic function of DS.
Insights
Murine trisomy 16 (Ts16) cells show reduced cyclic AMP (cAMP) response to adrenergic ligands, unlike Down
Area of Science:
- Genetics
- Pharmacology
- Cell Biology
Background:
- Murine trisomy 16 (Ts16) is a model for Down's syndrome (DS) due to gene homology with human chromosome 21.
- Down's syndrome is characterized by altered sensitivity to adrenergic ligands.
Purpose of the Study:
- To investigate the adrenergic ligand sensitivity in murine Ts16 fibroblasts and embryonic cells.
- To determine if Ts16 is an appropriate model for studying altered adrenergic function in DS.
Main Methods:
- Exposure of Ts16 cells to epinephrine and isoproterenol.
- Measurement of cyclic AMP (cAMP) accumulation in response to adrenergic ligands and prostaglandin E1.
Main Results:
- Ts16 cells exhibited a 2-4 fold reduction in cAMP accumulation upon stimulation with beta 1-adrenergic ligands (epinephrine, isoproterenol).
- A similar reduction in cAMP was observed in response to prostaglandin E1, suggesting a broader adenylcyclase issue.
- This response differs from that observed in cells from DS individuals.
Conclusions:
- Murine Ts16 cells do not accurately model the specific adrenergic dysfunction seen in Down's syndrome.
- The observed changes in Ts16 cells point to a generalized adenylcyclase alteration, not specific to DS-related adrenergic sensitivity.