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Project description:Glucagon (GCG) analogues are gaining attention as promising components in incretin-based therapeutics for obesity and metabolic dysfunction-associated steatohepatitis. However, the biology of chronic glucagon treatment, in particular, the molecular underpinnings of GCG-induced energy expenditure and lipid metabolism, remain poorly defined. We utilized a long-acting GCG analogue (LA-GCG) in conjunction with hepatic and adipose glucagon receptor knockout mouse models. Through an integrative approach that combined metabolic, biochemical and omics techniques, we investigated the molecular mechanisms underlying GCG-induced energy expenditure and metabolic benefits. We demonstrate that the LA-GCG enhances energy expenditure in diet-induced obese mice with an essential role of hepatic, but not adipose, GCGR signaling. Intriguingly, the enhancement in energy expenditure is observed only in obese but not in lean mice. The preferential efficacy is plausibly found in a prolonged activation of cAMP/PKA signaling through PDE4B/4D downregulation by LA-GCG. Conversely, the cAMP/PKA signaling is promptly attenuated by the PDE4B/4D activity in lean mice. Interestingly, unlike the EE phenotype, the lipid-clearing capacity of LA-GCG is independent of the PDE4/cAMP/PKA axis. These findings provide the molecular basis for GCG-induced energy expenditure and metabolic benefits and suggest the phenotypic segregation of cAMP/PKA-dependent and independent effects.
2025-06-24 | PXD062962 | Pride
Project description:Background & Aims: Glucagon (GCG) analogues are gaining attention as promising components in incretin-based therapeutics for obesity and metabolic dysfunction-associated steatohepatitis. However, the biology of chronic glucagon treatment, in particular, the molecular underpinnings of GCG-induced energy expenditure and lipid metabolism, remain poorly defined. Methods: We utilized a long-acting GCG analogue (LA-GCG) in conjunction with hepatic and adipose glucagon receptor knockout mouse models. Through an integrative approach that combined metabolic, biochemical and omics techniques, we investigated the molecular mechanisms underlying GCG-induced energy expenditure and metabolic benefits. Results: We demonstrate that the LA-GCG enhances energy expenditure in diet-induced obese mice with an essential role of hepatic, but not adipose, GCGR signaling. Intriguingly, the enhancement in energy expenditure is observed only in obese but not in lean mice. The preferential efficacy is plausibly found in a prolonged activation of cAMP/PKA signaling through PDE4B/4D downregulation by LA-GCG. Conversely, the cAMP/PKA signaling is promptly attenuated by the PDE4B/4D activity in lean mice. Interestingly, unlike the EE phenotype, the lipid-clearing capacity of LA-GCG is independent of the PDE4/cAMP/PKA axis. Conclusions: These findings provide the molecular basis for GCG-induced energy expenditure and metabolic benefits and suggest the phenotypic segregation of cAMP/PKA-dependent and independent effects.
2025-06-23 | GSE291380 | GEO
Project description:Background & Aims: Glucagon (GCG) analogues are gaining attention as promising components in incretin-based therapeutics for obesity and metabolic dysfunction-associated steatohepatitis. However, the biology of chronic glucagon treatment, in particular, the molecular underpinnings of GCG-induced energy expenditure and lipid metabolism, remain poorly defined. Methods: We utilized a long-acting GCG analogue (LA-GCG) in conjunction with hepatic and adipose glucagon receptor knockout mouse models. Through an integrative approach that combined metabolic, biochemical and omics techniques, we investigated the molecular mechanisms underlying GCG-induced energy expenditure and metabolic benefits. Results: We demonstrate that the LA-GCG enhances energy expenditure in diet-induced obese mice with an essential role of hepatic, but not adipose, GCGR signaling. Intriguingly, the enhancement in energy expenditure is observed only in obese but not in lean mice. The preferential efficacy is plausibly found in a prolonged activation of cAMP/PKA signaling through PDE4B/4D downregulation by LA-GCG. Conversely, the cAMP/PKA signaling is promptly attenuated by the PDE4B/4D activity in lean mice. Interestingly, unlike the EE phenotype, the lipid-clearing capacity of LA-GCG is independent of the PDE4/cAMP/PKA axis. Conclusions: These findings provide the molecular basis for GCG-induced energy expenditure and metabolic benefits and suggest the phenotypic segregation of cAMP/PKA-dependent and independent effects.
2025-06-23 | GSE291381 | GEO
Project description:Glucagon controls obesity-specific energy expenditure via persistent cAMP/PKA signaling
| PRJNA1233268 | ENA
Project description:Glucagon controls obesity-specific energy expenditure via persistent cAMP/PKA signaling [RNA-Seq 2]
| PRJNA1233272 | ENA
Project description:Glucagon controls obesity-specific energy expenditure via persistent cAMP/PKA signaling [RNA-Seq 1]
| PRJNA1233269 | ENA
Project description:Many protein kinases are key nodal signaling molecules that regulate a wide range of cellular functions. These functions may require complex spatiotemporal regulation of kinase activities. Here, we show that protein kinase A (PKA), Ca(2+) and cyclic AMP (cAMP) oscillate in sync in insulin-secreting MIN6 beta cells, forming a highly integrated oscillatory circuit. We found that PKA activity was essential for this oscillatory circuit and was capable of not only initiating the signaling oscillations but also modulating their frequency, thereby diversifying the spatiotemporal control of downstream signaling. Our findings suggest that exquisite temporal control of kinase activity, mediated via signaling circuits resulting from cross-regulation of signaling pathways, can encode diverse inputs into temporal parameters such as oscillation frequency, which in turn contribute to proper regulation of complex cellular functions in a context-dependent manner.
| S-EPMC3073414 | biostudies-other
Project description:The fidelity of intracellular signaling hinges on the organization of dynamic activity architectures. Spatial compartmentation was first proposed over 30 years ago to explain how diverse G protein-coupled receptors achieve specificity despite converging on a ubiquitous messenger, cyclic adenosine monophosphate (cAMP). However, the mechanisms responsible for spatially constraining this diffusible messenger remain elusive. Here, we reveal that the type I regulatory subunit of cAMP-dependent protein kinase (PKA), RIα, undergoes liquid-liquid phase separation (LLPS) as a function of cAMP signaling to form biomolecular condensates enriched in cAMP and PKA activity, critical for effective cAMP compartmentation. We further show that a PKA fusion oncoprotein associated with an atypical liver cancer potently blocks RIα LLPS and induces aberrant cAMP signaling. Loss of RIα LLPS in normal cells increases cell proliferation and induces cell transformation. Our work reveals LLPS as a principal organizer of signaling compartments and highlights the pathological consequences of dysregulating this activity architecture.
| S-EPMC7502557 | biostudies-literature
Project description:Memory consolidation is defined by the stabilization of a memory trace after acquisition, and consists of numerous molecular cascades that mediate synaptic plasticity. Commonly, a distinction is made between an early and a late consolidation phase, in which early refers to the first hours in which labile synaptic changes occur, whereas late consolidation relates to stable and long-lasting synaptic changes induced by de novo protein synthesis. How these phases are linked at a molecular level is not yet clear. Here we studied the interaction of the cyclic nucleotide-mediated pathways during the different phases of memory consolidation in rodents. In addition, the same pathways were studied in a model of neuronal plasticity, long-term potentiation (LTP). We demonstrated that cGMP/protein kinase G (PKG) signaling mediates early memory consolidation as well as early-phase LTP, whereas cAMP/protein kinase A (PKA) signaling mediates late consolidation and late-phase-like LTP. In addition, we show for the first time that early-phase cGMP/PKG signaling requires late-phase cAMP/PKA-signaling in both LTP and long-term memory formation.
| S-EPMC4207334 | biostudies-literature
Project description:BackgroundCystic fibrosis (CF) is characterized by reduced growth and lower body weight, which are multifactorial. CF mouse models lack key disease characteristics that predispose to a negative energy balance, such as pulmonary infections or exocrine pancreatic insufficiency, and yet they still exhibit a growth defect and an abnormally increased energy expenditure. Whether adipocyte thermogenesis contributes to the elevated resting energy expenditure in CF mice is unknown.MethodsWe examined the expression of CFTR in thermogenic brown adipose tissue (BAT) and investigated a functional role for CFTR using BAT-specific CFTR null mice (CFTRBATKO).ResultsThe CFTR protein is expressed in mouse BAT at levels comparable to those in the lungs. BAT-specific inactivation of CFTR in mice increases whole-body energy expenditure associated with sympathetic stimulation by cold exposure. Weight gain on a high-fat diet is attenuated in these mice. However, CFTR-deficient brown adipocytes themselves have impaired, rather than enhanced, thermogenic responses. These cells feature decreased lipolysis and blunted activation of the cAMP/PKA signaling pathway in response to adrenergic stimulation. This suggests that compensatory heat production in other tissues likely accounts for the increased systemic energy expenditure seen in CFTRBATKO mice.ConclusionsOur data reveal a new role for CFTR in the regulation of adipocyte thermogenesis.
| S-EPMC10332805 | biostudies-literature