Annexin A5 stabilizes matrix vesicle-biomimetic lipid membranes: unravelling a new role of annexins in calcification

Autor(es)

Ferreira, Claudio R. ; Cruz, Marcos Antonio E. ; Bolean, Mayte ; Andrilli, Luiz Henrique da S. ; Millan, Jose Luis ; Ramos, Ana Paula ; Bottini, Massimo ; Ciancaglini, Pietro

• Tipo de documento: Artigo Científico
• Fonte: EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS; v. 52, n. 8, p. 13-pg., 2023-11-08.

Resumo

Matrix vesicles are a special class of extracellular vesicles thought to actively contribute to both physiologic and pathologic mineralization. Proteomic studies have shown that matrix vesicles possess high amounts of annexin A5, suggesting that the protein might have multiple roles at the sites of calcification. Currently, Annexin A5 is thought to promote the nucleation of apatitic minerals close to the inner leaflet of the matrix vesicles' membrane enriched in phosphatidylserine and Ca2+. Herein, we aimed at unravelling a possible additional role of annexin A5 by investigating the ability of annexin A5 to adsorb on matrix-vesicle biomimetic liposomes and Langmuir monolayers made of dipalmitoylphosphatidylserine (DPPS) and dipalmitoylphosphatidylcholine (DPPC) in the absence and in the presence of Ca2+. Differential scanning calorimetry and dynamic light scattering measurements showed that Ca2+ at concentrations in the 0.5-2.0 mM range induced the aggregation of liposomes probably due to the formation of DPPS-enriched domains. However, annexin A5 avoided the aggregation of liposomes at Ca2+ concentrations lower than 1.0 mM. Surface pressure versus surface area isotherms showed that the adsorption of annexin A5 on the monolayers made of a mixture of DPPC and DPPS led to a reduction in the area of excess compared to the theoretical values, which confirmed that the protein favored attractive interactions among the membrane lipids. The stabilization of the lipid membranes by annexin A5 was also validated by recording the changes with time of the surface pressure. Finally, fluorescence microscopy images of lipid monolayers revealed the formation of spherical lipid-condensed domains that became unshaped and larger in the presence of annexin A5. Our data support the model that annexin A5 in matrix vesicles is recruited at the membrane sites enriched in phosphatidylserine and Ca2+ not only to contribute to the intraluminal mineral formation but also to stabilize the vesicles' membrane and prevent its premature rupture. (AU)

• Processo FAPESP: 19/08568-2 - Investigação do papel de vesículas extracelulares (VEs) na iniciação, propagação, regeneração e modelação da mineralização biológica
• Beneficiário: Pietro Ciancaglini
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 21/13140-1 - Estudo da interação de PHOSPHO1 e nSMase2 com membranas modelo: uma possível correlação na secreção de vesículas da matriz
• Beneficiário: Luiz Henrique da Silva Andrilli
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 19/25054-2 - Nanopartículas contendo estrôncio e sua versatilidade na fabricação de biomateriais: implicações e aplicações em biomineralização
• Beneficiário: Ana Paula Ramos
• Modalidade de apoio: Auxílio à Pesquisa - Regular