Effect of the presence of cholesterol in the interfacial microenvironment on the modulation of the alkaline phosphatase activity during in vitro mineralization

Author(s)

Favarin, B. Z. ; Andrade, M. A. R. ; Bolean, M. ; Simao, A. M. S. ; Ramos, A. P. ; Hoylaerts, M. F. ; Millan, J. L. ; Ciancaglini, P.

• Document type: Journal article
• Source: COLLOIDS AND SURFACES B-BIOINTERFACES; v. 155, p. 466-476, JUL 1 2017.
• Web of Science Citations: 9

Abstract

Mineralization of the skeleton starts within cell-derived matrix vesicles (MVs); then, minerals propagate to the extracellular collagenous matrix. Tissue-nonspecific alkaline phosphatase (TNAP) degrades inorganic pyrophosphate (PPi), a potent inhibitor of mineralization, and contributes P-i (Phosphate) from ATP to initiate mineralization. Compared to the plasma membrane, MVs are rich in Cholesterol (Chol) (similar to 32%) and TNAP, but how Chol influences TNAP activity remains unclear. We have reconstituted TNAP in liposomes of dipalmitoylphosphatidylcholine (DPPC) or dioleoylphosphatidylcholine (DOPC) combined with Chol or its derivatives Cholestenone (Achol) and Ergosterol (Ergo). DPPC plus 36% sterols in liposome increased the catalytic activity of TNAP toward ATP. The presence of Chol also increased the propagation of minerals by 3.4-fold. The catalytic efficiency of TNAP toward ATP was fourfold lower in DOPC proteoliposomes as compared to DPPC proteoliposomes. DOPC proteoliposomes also increased biomineralization by 2.8-fold as compared to DPPC proteoliposomes. TNAP catalyzed the hydrolysis of ATP more efficiently in the case of the proteoliposome consisting of DOPC with 36% Chol. The same behavior emerged with Achol and Ergo. The organization of the lipid and the structure of the sterol influenced the surface tension (gamma), the TNAP phosphohydrolytic activity in the monolayer, and the TNAP catalytic efficiency in the bilayers. Membranes in the Lot phase (Achol) provided better kinetic parameters as compared to membranes in the Lo phase (Chol and Ergo). In conclusion, the physical properties and the lateral organization of lipids in proteoliposomes are crucial to control mineral propagation mediated by TNAP activity during mineralization. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 16/21236-0 - Extracellular matrix vesicles (MVs) mimetic systems to study the regulation of the biomineralization process: proteoliposomes containing NPP1 and Annexin V
• Grantee: Pietro Ciancaglini
• Support Opportunities: Regular Research Grants
• FAPESP's process: 15/00345-3 - Lipid microdomains in Langmuir-Blodgett films rich in alkaline phosphatase to obtain a Ti surface osteoinductive
• Grantee: Marco Aurélio Raz de Andrade
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 12/20946-3 - Study of the growth of calcium phosphates and carbonates on organic matrices deposited on mettalic supports: obtainment of osteoinductive biomaterials
• Grantee: Ana Paula Ramos
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/11941-3 - Are collagen and Annexin V responsible for the control in the biomineralization process?
• Grantee: Pietro Ciancaglini
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/00371-1 - Are the interactions between collagen and proteins/enzymes present in the matriz vesicles responsible for the control in the biomineralization process?
• Grantee: Maytê Bolean Correia
• Support Opportunities: Scholarships in Brazil - Post-Doctoral