Metabolites of an Epac-Selective cAMP Analog Induce Cortisol Synthesis by Adrenocortical Cells through a cAMP-Independent Pathway

Adrenal zona fasciculata (AZF) cells express a cAMP-activated guanine nucleotide exchange protein (Epac2) that may function in ACTH-stimulated cortisol synthesis. Experiments were done to determine whether cAMP analogs that selectively activate Epacs could induce cortisol synthesis and the expression of genes coding for steroidogenic proteins in bovine AZF cells. Treatment of AZF cells with the Epac-selective cAMP analog (ESCA) 8CPT-2′-OMe-cAMP induced large (>100 fold), concentration-dependent, delayed increases in cortisol synthesis and the expression of mRNAs coding for the steroid hydroxylases CYP11a1, CYP17, CYP21, and the steroid acute regulatory protein (StAR). However, a non-hydrolyzable analog of this ESCA, Sp-8CPT-2′-OMe-cAMP, failed to stimulate cortisol production even at concentrations that activated Rap1, a downstream effector of Epac2. Accordingly, putative metabolites of 8CPT-2′-OMe-cAMP, including 8CPT-2′-OMe-5′AMP, 8CPT-2′-OMe-adenosine, and 8CPT-adenine all induced cortisol synthesis and steroid hydroxylase mRNA expression with a temporal pattern, potency, and effectiveness similar to the parent compound. At concentrations that markedly stimulated cortisol production, none of these metabolites significantly activated cAMP-dependent protein kinase (PKA). These results show that one or more metabolites of the ESCA 8CPT-2′-OMe-cAMP induce cortico-steroidogenesis by activating a panel of genes that code for steroidogenic proteins. The remarkable increases in cortisol synthesis observed in this study appear to be mediated by a novel cAMP-, Epac- and PKA-independent signaling pathway

Trieste and Louis Adamic’s Transnational Identities

Članek s pomočjo prizadevanj slovenskega priseljenca v Združene države in svetovno znanega pisatelja Louisa Adamiča, da bi krmaril med svojima dvema identitetama, jugoslovansko in ameriško, kaže, kaj v praksi pomeni transnacionalna identiteta. Na podlagi Adamičevih splošnih zapisov o Trstu in Italiji osvetljuje njegov prehod od vodje diaspore med drugo svetovno vojno do antikolonialista v letih 1946–1951. Analiza Adamičeve aktivistične drže do Trsta omogoča lažje razumevanje transnacionalizma onkraj posameznikovega čezmejnega premika oziroma posameznikove trenutne identitetne opredelitve. Adamičeva prizadevanja, da bi vlado ZDA prepričal o nujnosti jugoslovanskega nadzora Trsta, omogočajo vpogled v delovanje transnacionalizma kot identitete v gibanju.By examining Slovene immigrant to the United States and world-renowned author Louis Adamic’s effort to mediate between his Yugoslav and American identities, this article helps us to think what having a transnational identity means. By focusing on Adamic’s writings about Trieste and Italy in general, the article shows how he transitioned from being a disaporic leader during World War II to an anti-colonialist from 1946–1951. Examining Adamic’s activist stances regarding Trieste helps us to think about transnationalism beyond a single cross-border movement or an individual’s identity claim at a specific moment. Adamic’s effort to convince the U.S. government that Yugoslavia should control Trieste allows us to see how transnationalism operated as an identity in flux

ACTH Inhibits bTREK-1 K+ Channels through Multiple cAMP-dependent Signaling Pathways

Bovine adrenal zona fasciculata (AZF) cells express bTREK-1 K+ channels that set the resting membrane potential and function pivotally in the physiology of cortisol secretion. Inhibition of these K+ channels by adrenocorticotropic hormone (ACTH) or cAMP is coupled to depolarization and Ca2+ entry. The mechanism of ACTH and cAMP-mediated inhibition of bTREK-1 was explored in whole cell patch clamp recordings from AZF cells. Inhibition of bTREK-1 by ACTH and forskolin was not affected by the addition of both H-89 and PKI(6–22) amide to the pipette solution at concentrations that completely blocked activation of cAMP-dependent protein kinase (PKA) in these cells. The ACTH derivative, O-nitrophenyl, sulfenyl-adrenocorticotropin (NPS-ACTH), at concentrations that produced little or no activation of PKA, inhibited bTREK-1 by a Ca2+-independent mechanism. Northern blot analysis showed that bovine AZF cells robustly express mRNA for Epac2, a guanine nucleotide exchange protein activated by cAMP. The selective Epac activator, 8-pCPT-2′-O-Me-cAMP, applied intracellularly through the patch pipette, inhibited bTREK-1 (IC50 = 0.63 μM) at concentrations that did not activate PKA. Inhibition by this agent was unaffected by PKA inhibitors, including RpcAMPS, but was eliminated in the absence of hydrolyzable ATP. Culturing AZF cells in the presence of ACTH markedly reduced the expression of Epac2 mRNA. 8-pCPT-2′-O-Me-cAMP failed to inhibit bTREK-1 current in AZF cells that had been treated with ACTH for 3–4 d while inhibition by 8-br-cAMP was not affected. 8-pCPT-2′-O-Me-cAMP failed to inhibit bTREK-1 expressed in HEK293 cells, which express little or no Epac2. These findings demonstrate that, in addition to the well-described PKA-dependent TREK-1 inhibition, ACTH, NPS-ACTH, forskolin, and 8-pCPT-2′-O-Me-cAMP also inhibit these K+ channels by a PKA-independent signaling pathway. The convergent inhibition of bTREK-1 through parallel PKA- and Epac-dependent mechanisms may provide for failsafe membrane depolarization by ACTH

Death to Fascism : Louis Adamic\u27s Fight for Democracy

Born to Slovenian peasants, Louis Adamic commanded crowds, met with FDR and Truman, and built a prolific career as an author and journalist. Behind the scenes, he played a leading role in a coalition of black intellectuals and writers, working-class militants, ethnic activists, and others that worked for a multiethnic America and against fascism. John P. Enyeart restores Adamic\u27s life to the narrative of American history. Dogged and energetic, Adamic championed causes that ranged from ethnic and racial equality to worker\u27s rights to anticolonialism. Adamic defied the consensus that equated being American with Anglo-Protestant culture. Instead, he insisted newcomers and their ideas kept the American identity in a state of dynamism that pushed it from strength to strength. In time, Adamic\u27s views put him at odds with an establishment dedicated to cold war aggression and white supremacy. He increasingly fought smear campaigns and the distortion of his views—both of which continued after his probable murder in 1951. -- publisherhttps://digitalcommons.bucknell.edu/books/1056/thumbnail.jp