38 research outputs found
Activation of Crtc2/Creb1 in skeletal muscle enhances weight loss during intermittent fasting
The Creb-Regulated Transcriptional Coactivator (Crtc) family of transcriptional coregulators drive Creb1-mediated transcription effects on metabolism in many tissues, but the in vivo effects of Crtc2/Creb1 transcription on skeletal muscle metabolism are not known. Skeletal muscle-specific overexpression of Crtc2 (Crtc2 mice) induced greater mitochondrial activity, metabolic flux capacity for both carbohydrates and fats, improved glucose tolerance and insulin sensitivity, and increased oxidative capacity, supported by upregulation of key metabolic genes. Crtc2 overexpression led to greater weight loss during alternate day fasting (ADF), selective loss of fat rather than lean mass, maintenance of higher energy expenditure during the fast and reduced binge-eating during the feeding period. ADF downregulated most of the mitochondrial electron transport genes, and other regulators of mitochondrial function, that were substantially reversed by Crtc2-driven transcription. Glucocorticoids acted with AMPK to drive atrophy and mitophagy, which was reversed by Crtc2/Creb1 signaling. Crtc2/Creb1-mediated signaling coordinates metabolic adaptations in skeletal muscle that explain how Crtc2/Creb1 regulates metabolism and weight loss
The SARS-CoV-2 spike protein binds and modulates estrogen receptors
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein binds angiotensin-converting enzyme 2 as its primary infection mechanism. Interactions between S and endogenous proteins occur after infection but are not well understood. We profiled binding of S against >9000 human proteins and found an interaction between S and human estrogen receptor alpha (ER alpha). Using bioinformatics, supercomputing, and experimental assays, we identified a highly conserved and functional nuclear receptor coregulator (NRC) LXD-like motif on the S2 sub-unit. In cultured cells, S DNA transfection increased ER alpha cytoplasmic accumulation, and S treatment induced ER-dependent biological effects. Non-invasive imaging in SARS-CoV-2-infected hamsters localized lung pathology with increased ER alpha lung levels. Postmortem lung experiments from infected hamsters and humans confirmed an increase in cytoplasmic ER alpha and its colocalization with S in alveolar macrophages. These findings describe the discovery of a S-ER alpha interaction, imply a role for S as an NRC, and advance knowledge of SARS-CoV-2 biology and coronavirus disease 2019 pathology
CBP Is a Dosage-Dependent Regulator of Nuclear Factor-κB Suppression by the Estrogen Receptor
The estrogen receptor (ER) protects against debilitating effects of the inflammatory response by inhibiting the proinflammatory transcription factor nuclear factor-κB (NFκB). Heretofore cAMP response element-binding protein (CREB)-binding protein (CBP) has been suggested to mediate inhibitory cross talk by functioning either as a scaffold that links ER and NFκB or as a required cofactor that competitively binds to one or the other transcriptional factor. However, here we demonstrate that ER is recruited to the NFκB response element of the MCP-1 (monocyte chemoattractant protein-1) and IL-8 promoters and displaces CBP, but not p65, in the MCF-7 breast cancer cell line. In contrast, ER displaced p65 and associated coregulators from the IL-6 promoter, demonstrating a gene-specific role for CBP in integrating inflammatory and steroid signaling. Further, RNA interference and overexpression studies demonstrated that CBP dosage regulates estrogen-mediated suppression of MCP-1 and IL-8, but not IL-6, gene expression. This work further demonstrates that CBP dosage is a critical regulator of gene-specific signal integration between the ER- and NFκB-signaling pathways
Exploring the Structural Compliancy versus Specificity of the Estrogen Receptor Using Isomeric Three-Dimensional Ligands
Exploring the Structural Compliancy versus Specificity of the Estrogen Receptor Using Isomeric Three-Dimensional Ligands
The
estrogen receptors (ERs) bind with high affinity to many structurally
diverse ligands by significantly distorting the contours of their
ligand-binding pockets. This raises a question: To what degree is
ER able to distinguish between structurally related regioisomers and
enantiomers? We have explored the structural compliance and specificity
of ERα with a set of ligands having a 7-oxa-bicyclo[2.2.1]hept-5-ene
sulfonate core and basic side chains typical of selective ER modulators
(SERMs). These ligands have two regioisomers, each of which is a racemate
of enantiomers. Using orthogonal protecting groups and chiral HPLC,
we isolated all 4 isomers and assigned their absolute stereochemistry
by X-ray analysis. The 1S,2R,4S isomer has a 80–170-fold higher
affinity for ERα than the others, and it profiles as a partial
agonist/antagonist in cellular reporter gene assays and in suppressing
proliferation of MCF-7 breast cancer cells with subnanomolar potency,
far exceeding that of the other isomers. It is the only isomer found
bound to ERα by X-ray analysis after crystallization with four-isomer
mixtures of closely related analogs. Thus, despite the general compliance
of this receptor for binding a large variety of ligand structures,
ER demonstrates marked structural specificity and stereospecificity
by selecting a single component from a mixture of structurally related
isomers to drive ER-regulated cellular activity. Our findings lay
the necessary groundwork for seeking unique ER-mediated pharmacological
profiles by rational structural perturbations of two different types
of side chains in this unprecedented class of ER ligands, which may
prove useful in developing more effective endocrine therapies for
breast cancer