Topographic analysis by atomic force microscopy of proteoliposomes matrix vesicle mimetics harboring TNAP and AnxA5

Autor(es)

Bolean, Mayte ; Bonin, Ivana A. ; Simao, Ana M. S. ; Bottini, Massimo ; Bagatolli, Luis A. ; Hoylaerts, Marc F. ; Millan, Jose L. ; Ciancaglini, Pietro

• Tipo de documento: Artigo Científico
• Fonte: BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES; v. 1859, n. 10, p. 1911-1920, OCT 2017.
• Citações Web of Science: 9

Resumo

Atomic force microscopy (AFM) is one of the most commonly used scanning probe microscopy techniques for nanoscale imaging and characterization of lipid-based particles. However, obtaining images of such particles using AFM is still a challenge. The present study extends the capabilities of AFM to the characterization of proteoliposomes, a special class of liposomes composed of lipids and proteins, mimicking matrix vesicles (MVs) involved in the biomineralization process. To this end, proteoliposomes were synthesized, composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine (DPPS), with inserted tissue-nonspecific alkaline phosphatase (TNAP) and/or annexin V (AnxA5), both characteristic proteins of osteoblast-derived MVs. We then aimed to study how TNAP and AnxA5 insertion affects the proteoliposomes' membrane properties and, in turn, interactions with type II collagen, thus mimicking early MV activity during biomineralization. AFM images of these proteoliposomes, acquired in dynamic mode, revealed the presence of surface protrusions with distinct viscoelasticity, thus suggesting that the presence of the proteins induced local changes in membrane fluidity. Surface protrusions were measurable in TNAP-proteoliposomes but barely detectable in AnxA5-proteoliposomes. More complex surface structures were observed for proteoliposomes harboring both TNAP and AnxA5 concomitantly, resulting in a lower affinity for type II collagen fibers compared to proteoliposomes harboring AnxA5 alone. The present study achieved the topographic analysis of lipid vesicles by direct visualization of structural changes, resulting from protein incorporation, without the need for fluorescent probes. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 14/11941-3 - Colágeno e annexina são responsáveis pelo controle do processo de biomineralização?
• Beneficiário: Pietro Ciancaglini
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/00371-1 - Interações entre colágeno e proteínas/enzimas presentes nas vesículas da matriz são responsáveis pelo controle do processo de biomineralização?
• Beneficiário: Maytê Bolean Correia
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado