Therapeutic melanoma inhibition by local micelle-mediated cyclic nucleotide repression
Ontology highlight
ABSTRACT: The acidic tumor microenvironment in melanoma drives immune evasion by up-regulating cyclic adenosine monophosphate (cAMP) in tumor-infiltrating monocytes..Melanoma growth can be suppressed by releasing non-toxic concentrations of an adenylate cyclase (AC) inhibitor from polypept(o)id micelles at the tumor site in an immune cell-dependent manner.
Project description:Adenylate cyclase signaling pathway is suggested to be a key regulator of immune system functions. However, specific effects of cyclic adenosine monophosphate on T helper cell differentiation and functions are unclear. Involvement of cAMP in Th cell differentiation program, in particular development of Th1, Th2, and Th17 subsets, was evaluated employing forskolin (FSK), a labdane diterpene well known as AC activator.
Project description:Acetylation of lysine residues is conserved across organisms and plays important roles in various cellular functions. Maintaining intracellular pH homeostasis is crucial for the survival of enteric bacteria in acidic gastric tract. However, it remains unkown whether bacteria can utilize reversible protein acetylation system to adapt to acidic environment. Here we demonstrate that the protein acetylation/deacetylation is critical for Salmonella Typhimurium to survive in acidic environment. We first used RNA-seq to analyze the transcriptome patterns under acid stress, and found that the transcriptional levels of genes involved in NAD+/NADH metabolism were significantly changed, leading to the increase of intracellular NAD+/NADH ratio. Moreover, acid stress down-regulated the transcriptional level of pat (encoding an acetyltranseferase) and genes encoding adenylate cyclase and cAMP-regulatory protein (CRP) which regulates pat positively. Acid signal also affects TCA cycle to promote the consumption of Ac-CoA, which reduced the donor of acetylation. Lowered acetylation level is not only bacterial’s response to acid stress, but also positively regulates the survival rate of S. Typhimurium. The deletion mutant of pat had more stable intracellular pH, which paralleled with higher survival rate after acid treatment compared with the wild type strain and deletion mutant of cobB. Our data suggest that bacteria can down-regulate protein acetylation level to prevent intracellular pH further falling in acid stress, and this work may provide a new perspective to understand the bacterial acid resistance mechanism. To use RNA-seq to analyze the transcriptome patterns under acid stress
Project description:Acetylation of lysine residues is conserved across organisms and plays important roles in various cellular functions. Maintaining intracellular pH homeostasis is crucial for the survival of enteric bacteria in acidic gastric tract. However, it remains unkown whether bacteria can utilize reversible protein acetylation system to adapt to acidic environment. Here we demonstrate that the protein acetylation/deacetylation is critical for Salmonella Typhimurium to survive in acidic environment. We first used RNA-seq to analyze the transcriptome patterns under acid stress, and found that the transcriptional levels of genes involved in NAD+/NADH metabolism were significantly changed, leading to the increase of intracellular NAD+/NADH ratio. Moreover, acid stress down-regulated the transcriptional level of pat (encoding an acetyltranseferase) and genes encoding adenylate cyclase and cAMP-regulatory protein (CRP) which regulates pat positively. Acid signal also affects TCA cycle to promote the consumption of Ac-CoA, which reduced the donor of acetylation. Lowered acetylation level is not only bacterial’s response to acid stress, but also positively regulates the survival rate of S. Typhimurium. The deletion mutant of pat had more stable intracellular pH, which paralleled with higher survival rate after acid treatment compared with the wild type strain and deletion mutant of cobB. Our data suggest that bacteria can down-regulate protein acetylation level to prevent intracellular pH further falling in acid stress, and this work may provide a new perspective to understand the bacterial acid resistance mechanism.
Project description:The Bordetella adenylate cyclase toxinhemolysin (CyaA) and the α-hemolysin (HlyA) of Escherichia coli both belong to the family of cytolytic pore-forming Repeats in ToXin (RTX) cytotoxins. HlyA preferentially binds the αLβ2 integrin LFA-1 (CD11a/CD18) of leukocytes and can promiscuously bind and permeabilize also a variety of other cells. CyaA bears an Nterminal adenylyl cyclase enzyme (AC) domain linked to a pore-forming RTX cytolysin (Hly) moiety and binds the complement receptor 3 (CR3, αMβ2, CD11b/CD18 or Mac-1) of myeloid phagocytes, penetrates their plasma membrane and delivers into cytosol the AC enzyme. We constructed a set of CyaA/HlyA chimeras and show that the CyaC-acylated segment and the CR3-binding RTX domain of CyaA can be functionally replaced by the much shorter HlyCacylated and LFA-1-binding RTX moiety of HlyA. Instead of binding CR3, a CyaA1710/HlyA411-1024 chimera bound the LFA-1 receptor and effectively delivered the AC enzyme into Jurkat lymphoblastoma T cells. At high chimera concentrations (25 nM), the interaction with LFA-1 was not required for CyaA1-710/HlyA411-1024 binding to CHO cells. However, interaction with the LFA-1 receptor strongly enhanced the specific capacity of the bound CyaA1-710/HlyA411-1024 chimera to penetrate cells and deliver the AC enzyme into their cytosol. Hence, interaction of the acylated RTX moiety of HlyA with LFA-1 promoted a productive membrane interaction of the chimera. These results allow to delimit the residues 400 to 710 of CyaA as the 'AC translocon' sufficient for translocation of the AC enzyme polypeptide across the plasma membrane of target cells
Project description:The whooping cough agent, Bordetella pertussis, subverts dendritic cell (DCs) functions through powerful immunomodulatory activities of its toxins. Here we focused on the signaling action of the adenylate cyclase toxin (CyaA) that targets myeloid cells expressing the αMβ2 integrin CD11b/CD18 (known as complement receptor 3 (CR3) or Mac-1). CyaA delivers an extremely catalytically potent adenylyl cyclase enzyme domain into the cytosol of phagocytes and disrupts their innate and adaptive immune functions through unregulated production of the key signaling molecule cAMP. Here we describe the global phosphoproteomic analysis of cAMP signaling in murine bone marrow-derived DCs exposed to CyaA. Gathered data reveal toxin-triggered alternations of phosphorylation status of proteins regulating actin cytoskeleton, chromatin remodeling, mTOR activity and IL-10 gene expression. The reported findings highlight the complexity of subversive physiological manipulation that is exerted on myeloid phagocytes by the cAMP-generating adenylate cyclase toxin of Bordetellae.
Project description:The aim of this study was to evaluate changes in the transcriptome due to the lack of adenylate cyclase in light or darkness. As the cAMP pathway represents an output pathway of heterotrimeric G-protein signaling ACY1 is likely to be important for regulation of enzymes in response to different nutrient conditions. Also, a light dependent effect was found earlier.