Calcium depletion-mediated protease inhibition and apical-junctional- complex disassembly via an EGTA-conjugated carrier for oral insulin delivery

Er-Tuan Chuang, Kun Ju Lin, Fang Yi Su, Hsin Lung Chen, Barnali Maiti, Yi Cheng Ho, Tzu Chen Yen, Nilendu Panda, Hsing Wen Sung

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Calcium (Ca2+) has a crucial role in maintaining the intestinal protease activity and in forming the apical junctional complex (AJC) that preserves epithelial barrier function. Ethylene glycol tetraacetic acid (EGTA) is a Ca2+-specific chelating agent. To maintain the concentration of this chelator in areas where enzyme inhibition and paracellular permeation enhancement are needed, this study synthesized a poly(γ-glutamic acid)-EGTA conjugate (γPGA-EGTA) to form nanoparticles (NPs) with chitosan (CS) for oral insulin delivery. The results of our molecular dynamic (MD) simulations indicate that Ca2+ ions could be specifically chelated to the nitrogen atoms, ether oxygen atoms, and carboxylate oxygen atoms in [Ca(EGTA)]2- anions. By che-lating Ca2+, γPGA-EGTA conferred a significant insulin protection effect against proteases in intestinal tracts isolated from rats. Additionally, calcium depletion by γPGA-EGTA could stimulate the endocytosis of AJC components in Caco-2 cell monolayers, which led to a reversible opening of AJCs and thus increased their paracellular permeability. Single-photon emission computed tomography images performed in the biodistribution study clearly show the 123I-insulin orally delivered by CS/γPGA-EGTA NPs in the heart, aorta, renal cortex, renal pelvis and liver, which ultimately produced a significant and prolonged hypoglyce-mic effect in diabetic rats. The above results confirm that this γPGA-EGTA conjugate is a promising candidate for oral insulin delivery.

Original languageEnglish
Pages (from-to)296-305
Number of pages10
JournalJournal of Controlled Release
Volume169
Issue number3
DOIs
Publication statusPublished - 2013
Externally publishedYes

Fingerprint

Egtazic Acid
Peptide Hydrolases
Insulin
Calcium
Glutamic Acid
Chitosan
Chelating Agents
Nanoparticles
Oxygen
Kidney Pelvis
Caco-2 Cells
Molecular Dynamics Simulation
Endocytosis
Single-Photon Emission-Computed Tomography
Ether
Anions
Aorta
Permeability
Nitrogen
Ions

Keywords

  • Apical junctional complex
  • Calcium depletion
  • Chelating agent
  • Enzyme inhibition
  • Oral protein delivery

ASJC Scopus subject areas

  • Pharmaceutical Science

Cite this

Calcium depletion-mediated protease inhibition and apical-junctional- complex disassembly via an EGTA-conjugated carrier for oral insulin delivery. / Chuang, Er-Tuan; Lin, Kun Ju; Su, Fang Yi; Chen, Hsin Lung; Maiti, Barnali; Ho, Yi Cheng; Yen, Tzu Chen; Panda, Nilendu; Sung, Hsing Wen.

In: Journal of Controlled Release, Vol. 169, No. 3, 2013, p. 296-305.

Research output: Contribution to journalArticle

Chuang, Er-Tuan ; Lin, Kun Ju ; Su, Fang Yi ; Chen, Hsin Lung ; Maiti, Barnali ; Ho, Yi Cheng ; Yen, Tzu Chen ; Panda, Nilendu ; Sung, Hsing Wen. / Calcium depletion-mediated protease inhibition and apical-junctional- complex disassembly via an EGTA-conjugated carrier for oral insulin delivery. In: Journal of Controlled Release. 2013 ; Vol. 169, No. 3. pp. 296-305.
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