The t-SNARE Syntaxin 4 Is Regulated during Macrophage Activation to Function in Membrane Traffic and Cytokine Secretion

Pagan, Julia K.; Wylie, Fiona G.; Joseph, Shannon R.; Widberg, Charlotte; Bryant, Nia J.; James, David E.; Stow, Jennifer L.

doi:10.1016/s0960-9822(03)00006-x

Cited by 109 publications

(129 citation statements)

References 25 publications

(2 reference statements)

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“…Targeting SNAP23 by a substrate modified BoNT may reduce the secretion processes of hypersecretion syndromes. A SNAP23-specific BoNT may also be targeted for other therapeutic applications that include diabetes and inflammatory and immune disorders which include a hypersecretory component (27,28).…”

Section: Discussionmentioning

confidence: 99%

Engineering botulinum neurotoxin to extend therapeutic intervention

Chen

Barbieri

2009

Proc. Natl. Acad. Sci. U.S.A.

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Clostridium botulinum neurotoxins (BoNTs) are effective therapeutics for a variety of neurological disorders, such as strabismus, blepharospam, hemificial spasm, and cervical dystonia, because of the toxin's tropism for neurons and specific cleavage of neuronal soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptors (SNARE) proteins. Modifying BoNT to bind nonneuronal cells has been attempted to extend therapeutic applications. However, prerequisite to develop nonneuronal therapies requires the retargeting the catalytic activity of BoNTs to nonneuronal SNARE isoforms. Here, we reported the engineering of a BoNT derivative that cleaves SNAP23, a nonneuronal SNARE protein. SNAP23 mediates vesicle-plasma membrane fusion processes, including secretion of airway mucus, antibody, insulin, gastric acids, and ions. This mutated BoNT/E light chain LC/E(K 224 D) showed extended substrate specificity to cleave SNAP23, and the natural substrate, SNAP25, but not SNAP29 or SNAP47. Upon direct protein delivery into cultured human epithelial cells, LC/E(K 224 D) cleaved endogenous SNAP23, which inhibited secretion of mucin and IL-8. These studies show the feasibility of genetically modifying LCs to target a nonneuronal SNARE protein that extends therapeutic potential for treatment of human hypersecretion diseases.Clostridium botulinum neurotoxins (BoNTs) are the most potent protein toxins for humans (1). BoNTs elicit neuronal-specific flaccid paralysis by targeting neurons and cleaving neuronspecific soluble N-ethylmaleimide-sensitive fusion proteinattachment protein receptors (SNARE) proteins. BoNTs are organized into 3 functional domains: an N-terminal zinc-metalloprotease light chain (LC), a translocation domain (HCT), and a C-terminal receptor binding domain (HCR) (1, 2). BoNTs bind luminal domains of synaptic vesicle proteins, upon the fusion of synaptic vesicles with the plasma membrane (3-5). BoNTs are internalized into endosomes and upon acidification, the LC is translocated into the cytoplasm, where SNARE proteins are cleaved (1, 2).Mammalian neuronal exocytosis is driven by the formation of protein complexes between the vesicle SNARE, VAMP2, and the plasma membrane SNAREs, SNAP25 and syntaxin 1a (6). There are 7 serotypes of BoNTs (termed A-G) that cleave specific residues on 1 of 3 SNARE proteins: serotypes B, D, F, and G cleave VAMP-2, serotypes A and E cleave SNAP25, and serotype C cleaves SNAP25 and syntaxin 1a (1). Thus, neuronal specificity is based upon BoNT binding to neurons and cleaving neuronal isoforms of the SNARE proteins. For example, BoNT/A cleaves human SNAP25, but not the human nonneuronal isoform SNAP23 (7,8). The nonneuronal SNARE isoforms are involved in divergent cellular processes, including fusion reactions in cell growth, membrane repair, cytokinesis, and synaptic transmission (reviewed in 9).The reversible nature of muscle function after BoNT intoxication that replace toxin-affected nerves with new nerves (10) has turned the BoNT from a deadly agent to therapies for neu...

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Section: Discussionmentioning

confidence: 99%

Engineering botulinum neurotoxin to extend therapeutic intervention

Chen

Barbieri

2009

Proc. Natl. Acad. Sci. U.S.A.

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“…TNF staining was performed as described (38). Cells were fixed and incubated with rabbit polyclonal anti-mouse TNF Ab (Calbiochem), followed by an Alexa Fluor 555-conjugated anti-rabbit Ab (Invitrogen).…”

Section: Fluorescence Microscopymentioning

confidence: 99%

RP105 Engages Phosphatidylinositol 3-Kinase p110δ To Facilitate the Trafficking and Secretion of Cytokines in Macrophages during Mycobacterial Infection

Micaroni

Puyskens

et al. 2015

The Journal of Immunology

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Cytokines are key regulators of adequate immune responses to infection with Mycobacterium tuberculosis. We demonstrate that the p110δ catalytic subunit of PI3K acts as a downstream effector of the TLR family member RP105 (CD180) in promoting mycobacteria-induced cytokine production by macrophages. Our data show that the significantly reduced release of TNF and IL-6 by RP105−/− macrophages during mycobacterial infection was not accompanied by diminished mRNA or protein expression. Mycobacteria induced comparable activation of NF-κB and p38 MAPK signaling in wild-type (WT) and RP105−/− macrophages. In contrast, mycobacteria-induced phosphorylation of Akt was abrogated in RP105−/− macrophages. The p110δ-specific inhibitor, Cal-101, and small interfering RNA–mediated knockdown of p110δ diminished mycobacteria-induced TNF secretion by WT but not RP105−/− macrophages. Such interference with p110δ activity led to reduced surface-expressed TNF in WT but not RP105−/− macrophages, while leaving TNF mRNA and protein expression unaffected. Activity of Bruton’s tyrosine kinase was required for RP105-mediated activation of Akt phosphorylation and TNF release by mycobacteria-infected macrophages. These data unveil a novel innate immune signaling axis that orchestrates key cytokine responses of macrophages and provide molecular insight into the functions of RP105 as an innate immune receptor for mycobacteria.

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“…LPS and IFN-␥, which both regulate gpnmb mRNA, also cause profound changes in post-Golgi trafficking (31,32). We therefore examined whether treatment of RAW264.7/gpnmb cells with these proinflammatory agents might provoke changes in GPNMB localization.…”

Section: Lps and Ifn-␥ Synergistically Induced Changes In The Localizmentioning

confidence: 99%

Gpnmb Is Induced in Macrophages by IFN-γ and Lipopolysaccharide and Acts as a Feedback Regulator of Proinflammatory Responses

Ripoll

Irvine

Ravasi

et al. 2007

The Journal of Immunology

189

187

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The process of inflammation requires the selective expression of a suite of genes in cells of the macrophage lineage. To identify candidate regulators of inflammation, we used cDNA microarrays to compare the transcriptome of inflammatory macrophages (thioglycolate-elicited peritoneal macrophages), bone marrow-derived macrophages, nonadherent spleen cells, and fibroblasts. We identified genes that were macrophage restricted and further elevated in inflammatory macrophages, and characterized the function of one such gene, gpnmb. Gpnmb mRNA expression was enriched in myelomonocytic cell lines and macrophage-related tissues and strongly up-regulated during macrophage differentiation. Epitope-tagged GPNMB expressed in RAW264.7 cells exhibited a perinuclear distribution and colocalized with the Golgi marker coat protein β. Upon activation of macrophages with IFN-γ and LPS, GPNMB translocated from the Golgi apparatus to vesicular compartments scattered toward the periphery. Gpnmb overexpression in RAW264.7 cells caused a 2-fold reduction in the production of the cytokines IL-6 and IL-12p40 and the inflammatory mediator NO in response to LPS. DBA mice, which have an inactivating point mutation in the gpnmb gene, exhibited reduced numbers of myeloid cells, elevated numbers of thioglycolate-elicited peritoneal macrophages, and higher levels of proinflammatory cytokines in response to LPS. Thus, GPNMB acts as a negative regulator of macrophage inflammatory responses.

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The t-SNARE Syntaxin 4 Is Regulated during Macrophage Activation to Function in Membrane Traffic and Cytokine Secretion

Cited by 109 publications

References 25 publications

Engineering botulinum neurotoxin to extend therapeutic intervention

Engineering botulinum neurotoxin to extend therapeutic intervention

RP105 Engages Phosphatidylinositol 3-Kinase p110δ To Facilitate the Trafficking and Secretion of Cytokines in Macrophages during Mycobacterial Infection

Gpnmb Is Induced in Macrophages by IFN-γ and Lipopolysaccharide and Acts as a Feedback Regulator of Proinflammatory Responses

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