Affinity Purification and Partial Characterization of the Zonulin/Zonula Occludens Toxin (Zot) Receptor from Human Brain

Lu, Ruliang; Wang, W.; Uzzau, Sergio; Vigorito, Robert; Zielke, H. Ronald; Fasano, Alessio

doi:10.1046/j.1471-4159.2000.0740320.x

Cited by 57 publications

(38 citation statements)

References 28 publications

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“…These data were partially presented at the American Academy of Neurology 2004 annual meeting. (110,111,137) and the blood-brain barrier (96,84,116). Because of its ubiquitous distribution and its function, we hypothesized that dysregulation of the zonulin pathway may contribute to disease states that involve disordered intercellular communication, including malignant transformation and metastasis.…”

Section: Gliomamentioning

confidence: 99%

Zonulin and Its Regulation of Intestinal Barrier Function: The Biological Door to Inflammation, Autoimmunity, and Cancer

Fasano

2011

Physiological Reviews

776

633

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The primary functions of the gastrointestinal tract have traditionally been perceived to be limited to the digestion and absorption of nutrients and to electrolytes and water homeostasis. A more attentive analysis of the anatomic and functional arrangement of the gastrointestinal tract, however, suggests that another extremely important function of this organ is its ability to regulate the trafficking of macromolecules between the environment and the host through a barrier mechanism. Together with the gut-associated lymphoid tissue and the neuroendocrine network, the intestinal epithelial barrier, with its intercellular tight junctions, controls the equilibrium between tolerance and immunity to non-self antigens. Zonulin is the only physiological modulator of intercellular tight junctions described so far that is involved in trafficking of macromolecules and, therefore, in tolerance/immune response balance. When the finely tuned zonulin pathway is deregulated in genetically susceptible individuals, both intestinal and extraintestinal autoimmune, inflammatory, and neoplastic disorders can occur. This new paradigm subverts traditional theories underlying the development of these diseases and suggests that these processes can be arrested if the interplay between genes and environmental triggers is prevented by reestablishing the zonulin-dependent intestinal barrier function. This review is timely given the increased interest in the role of a “leaky gut” in the pathogenesis of several pathological conditions targeting both the intestine and extraintestinal organs.

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Section: Gliomamentioning

confidence: 99%

Zonulin and Its Regulation of Intestinal Barrier Function: The Biological Door to Inflammation, Autoimmunity, and Cancer

Fasano

2011

Physiological Reviews

776

633

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“…Both ZOT and zonulin activities on tjs are blocked by an inactive peptide that is derived from the N terminus of the secreted fragment of ZOT (7,9,12). This same sequence also shares strong sequence homology with the protease-activated receptor-2-like signature signaling peptide (11,13).…”

Section: Eliac Disease (Cd)mentioning

confidence: 99%

Gliadin Stimulation of Murine Macrophage Inflammatory Gene Expression and Intestinal Permeability Are MyD88-Dependent: Role of the Innate Immune Response in Celiac Disease

Thomas¹,

Sapone

Fasano

et al. 2006

The Journal of Immunology

200

153

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Recent studies have demonstrated the importance of TLR signaling in intestinal homeostasis. Celiac disease (CD) is an autoimmune enteropathy triggered in susceptible individuals by the ingestion of gliadin-containing grains. In this study, we sought to test the hypothesis that gliadin initiates this response by stimulating the innate immune response to increase intestinal permeability and by up-regulating macrophage proinflammatory gene expression and cytokine production. To this end, intestinal permeability and the release of zonulin (an endogenous mediator of gut permeability) in vitro, as well as proinflammatory gene expression and cytokine release by primary murine macrophage cultures, were measured. Gliadin and its peptide derivatives, 33-mer and p31-43, were found to be potent inducers of both a zonulin-dependent increase in intestinal permeability and macrophage proinflammatory gene expression and cytokine secretion. Gliadin-induced zonulin release, increased intestinal permeability, and cytokine production were dependent on myeloid differentiation factor 88 (MyD88), a key adapter molecule in the TLR/IL-1R signaling pathways, but were neither TLR2- nor TLR4-dependent. Our data support the following model for the innate immune response to gliadin in the initiation of CD. Gliadin interaction with the intestinal epithelium increases intestinal permeability through the MyD88-dependent release of zonulin that, in turn, enables paracellular translocation of gliadin and its subsequent interaction with macrophages within the intestinal submucosa. There, the interaction of gliadin with macrophages elicits a MyD88-dependent proinflammatory cytokine milieu that facilitates the interaction of T cells with APCs, leading ultimately to the Ag-specific adaptive immune response seen in patients with CD.

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“…The discovery of Zot shed some light on the intricate mechanisms that govern the permeability of tj and led to the discovery of zonulin, the natural ligand of the Zot target receptor. The partial characterization of this zonulin receptor revealed that it is a 45-kDa glycoprotein containing multiple sialic acid residues with structural similarities to myeloid-related protein, a member of the calcium-binding protein family possibly linked to cytoskeletal rearrangements (18).…”

Section: Construction Of Zot Deletionmentioning

confidence: 99%

“…To clarify the Zot bifunctional activity, we analyzed the structure-function properties of the toxin by constructing a series of deletion mutants that were tested for their ability to both modulate tj and bind to the Zot/zonulin receptor (18). The results provide evidence that the active domain responsible for Zot enterotoxic activity resides toward the carboxyl-terminal region of the toxin.…”

mentioning

confidence: 99%

Zonula Occludens Toxin Structure-Function Analysis

Pierro

Lu²,

Uzzau

et al. 2001

Journal of Biological Chemistry

179

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Zonula occludens toxin (Zot) is an enterotoxin elaborated by Vibrio cholerae that increases intestinal permeability by interacting with a mammalian cell receptor with subsequent activation of intracellular signaling leading to the disassembly of the intercellular tight junctions. Zot localizes in the bacterial outer membrane of V. cholerae with subsequent cleavage and secretion of a carboxyl-terminal fragment in the host intestinal milieu. To identify the Zot domain(s) directly involved in the protein permeating effect, several zot gene deletion mutants were constructed and tested for their biological activity in the Ussing chamber assay and their ability to bind to the target receptor on intestinal epithelial cell cultures. The Zot biologically active domain was localized toward the carboxyl terminus of the protein and coincided with the predicted cleavage product generated by V. cholerae. This domain shared a putative receptor-binding motif with zonulin, the Zot mammalian analogue involved in tight junction modulation. Amino acid comparison between the Zot active fragment and zonulin, combined with site-directed mutagenesis experiments, confirmed the presence of an octapeptide receptor-binding domain toward the amino terminus of the processed Zot.Vibrio cholerae produces a variety of extracellular products including zonula occludens toxin (Zot) 1 (1). The zot gene, along with other genes encoding virulence factors such as ctxA, ctxB (2, 3), and ace (4), is part of the chromosomally integrated genome of a filamentous phage designated CTX⌽ (5-10). The zot product seems to be involved in the CTX⌽ morphogenesis because Zot mutagenesis studies demonstrated the inability of CTX elements to be self-transmissible under appropriate conditions (5). The high concurrence among V. cholerae strains of the zot gene and the ctx genes (11, 12) also suggests a possible synergistic role of Zot in the causation of acute dehydrating diarrhea typical of cholera. The recently completed genomic sequence of V. choleare El Tor N16961 revealed that the CTX⌽ filamentous phage is integrated in one of the two circular chromosomes of the bacterium (13).Beside its role in phage morphogenesis, Zot also increases the permeability of the small intestine by affecting the structure of the intercellular tight junctions (tj) (1). This effect was initially described on rabbit ileal tissues mounted in Ussing chambers by using filtered supernatants from V. cholerae O1 strains, suggesting that Zot is secreted (1, 14). Zot also possesses a cell specificity related to the toxin interaction with a specific receptor whose surface expression differs on various cells (15-17). Zot induces modifications of cytoskeletal organization that lead to the opening of tj secondary to the transmembrane phospholipase C and subsequent protein kinase C␣-dependent polymerization of actin filaments strategically localized to regulate the paracellular pathway (15). Furthermore, in vivo experiments suggested that the effect of Zot on tj might lead to intestinal secretion after...

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Affinity Purification and Partial Characterization of the Zonulin/Zonula Occludens Toxin (Zot) Receptor from Human Brain

Cited by 57 publications

References 28 publications

Zonulin and Its Regulation of Intestinal Barrier Function: The Biological Door to Inflammation, Autoimmunity, and Cancer

Zonulin and Its Regulation of Intestinal Barrier Function: The Biological Door to Inflammation, Autoimmunity, and Cancer

Gliadin Stimulation of Murine Macrophage Inflammatory Gene Expression and Intestinal Permeability Are MyD88-Dependent: Role of the Innate Immune Response in Celiac Disease

Zonula Occludens Toxin Structure-Function Analysis

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