scholarly journals Role of hypothalamic MAPK/ERK signaling in diabetes remission induced by the central action of fibroblast growth factor 1

2020 ◽  
Author(s):  
Jenny M. Brown ◽  
Marie A. Bentsen ◽  
Dylan M. Rausch ◽  
Bao Anh Phan ◽  
Danielle Wieck ◽  
...  

SummaryThe capacity of the brain to elicit sustained remission of hyperglycemia in rodent models of type 2 diabetes following intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1) is well established. Here, we show that following icv FGF1 injection, hypothalamic signaling by extracellular signal-regulated kinases 1 and 2 (ERK1/2), members of the mitogen-activated protein kinase (MAPK) family is induced for at least 24h. Further, we show that in diabetic Lepob/ob mice, this prolonged response is required for the sustained antidiabetic action of FGF1, since it is abolished by sustained (but not acute) pharmacologic blockade of hypothalamic MAPK/ERK signaling. We also demonstrate that FGF1 R50E, a FGF1 mutant that activates FGF receptors but induces only transient hypothalamic MAPK/ERK signaling, fails to mimic the sustained glucose lowering induced by FGF1. These data identify sustained activation of hypothalamic MAPK/ERK signaling as playing an essential role in the mechanism underlying diabetes remission induced by icv FGF1 administration.

2001 ◽  
Vol 281 (4) ◽  
pp. L766-L775 ◽  
Author(s):  
Isabel Carreras ◽  
Celeste B. Rich ◽  
Julie A. Jaworski ◽  
Sandra J. Dicamillo ◽  
Mikhail P. Panchenko ◽  
...  

Previously, we have demonstrated that basic fibroblast growth factor (bFGF) decreases elastin gene transcription in confluent rat lung fibroblasts via the binding of a Fra-1-c-Jun heterodimer to an activator protein-1-cAMP response element in the distal region of the elastin promoter. In the present study, we show that bFGF activates the mitogen-activated protein kinase extracellular signal-regulated kinase 1/2, resulting in the translocation of phosphorylated extracellular signal-regulated kinase 1/2 into the nucleus followed by increased binding of Elk-1 to the serum response element of the c-Fos promoter, transient induction of c-Fos mRNA, and sustained induction of Fra-1 mRNA. The addition of PD-98059, an inhibitor of mitogen-activated protein kinase kinase, abrogates the bFGF-dependent repression of elastin mRNA expression. Comparative analyses of confluent and subconfluent fibroblast cultures reveal significant differences in elastin mRNA levels and activator protein-1 protein factors involved in the regulation of elastin transcription. These findings suggest that bFGF modulates specific cellular events that are dependent on the state of the cell and provide a rationale for the differential responses that can be expected in development and injury or repair situations.


2021 ◽  
Author(s):  
Jenny M. Brown ◽  
Marie A. Bentsen ◽  
Dylan M. Rausch ◽  
Bao Anh Phan ◽  
Danielle Wieck ◽  
...  

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 214-OR
Author(s):  
JENNY M. BROWN ◽  
BAO ANH N. PHAN ◽  
HUZAIFA WASANWALA ◽  
MILES E. MATSEN ◽  
ANNA SECHER ◽  
...  

2004 ◽  
Vol 24 (13) ◽  
pp. 5657-5666 ◽  
Author(s):  
Betty Lamothe ◽  
Masashi Yamada ◽  
Ute Schaeper ◽  
Walter Birchmeier ◽  
Irit Lax ◽  
...  

ABSTRACT The docking protein Gab1 has been implicated as a mediator of multiple signaling pathways that are activated by a variety of receptor tyrosine kinases and cytokines. We have previously proposed that fibroblast growth factor 1 (FGF1) stimulation of tyrosine phosphorylation of Gab1 and recruitment of phosphatidylinositol (PI) 3-kinase are mediated by an indirect mechanism in which the docking protein fibroblast receptor substrate 2α (FRS2α) plays a critical role. In this report, we explore the role of Gab1 in FGF1 signaling by using mouse embryo fibroblasts (MEFs) derived from Gab1−/− or FRS2α−/− mice. We demonstrate that Gab1 is essential for FGF1 stimulation of both PI 3-kinase and the antiapoptotic protein kinase Akt, while FGF1-induced mitogen-activated protein kinase (MAPK) stimulation is not affected by Gab1 deficiency. To test the indirect mechanism for FGF1 stimulation of PI 3-kinase and Akt, we use a chimeric docking protein composed of the membrane targeting signal and the phosphotyrosine-binding domain of FRS2α fused to the C-terminal portion of Gab1, the region including the binding sites for the complement of signaling proteins that are recruited by Gab1. We demonstrate that expression of the chimeric docking protein in Gab1−/− MEFs rescues PI 3-kinase and the Akt responses, while expression of the chimeric docking protein in FRS2α−/− MEFs rescues stimulation of both Akt and MAPK. These experiments underscore the essential role of Gab1 in FGF1 stimulation of the PI 3-kinase/Akt signaling pathway and provide further support for the indirect mechanism for FGF1 stimulation of PI 3-kinase involving regulated assembly of a multiprotein complex.


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