Influence of the Bilayer Composition on the Binding and Membrane Disrupting Effect of Polybia-MP1, an Antimicrobial Mastoparan Peptide with Leukemic T-Lymphocyte Cell Selectivity

Author(s)

dos Santos Cabrera, Marcia Perez ^[1] ; Arcisio-Miranda, Manoel ^[2] ; Gorjao, Renata ^[3] ; Leite, Natalia Bueno ^[4] ; de Souza, Bibiana Monson ^[1] ; Curi, Rui ^[5] ; Procopio, Joaquim ^[5] ; Ruggiero Neto, Joao ^[4] ; Palma, Mario Sergio ^[1]

Affiliation

^[1] UNESP Sao Paulo State Univ, Ctr Studies Social Insects, Inst Biosci, BR-13506900 Rio Claro, SP - Brazil

^[2] UNIFESP Univ Fed Sao Paulo, Dept Biophys, BR-04923062 Sao Paulo - Brazil

^[3] Univ Cruzeiro Sul, Inst Sci Phys Educ & Sports, Postgrad Program Human Movement Sci, BR-01506000 Sao Paulo - Brazil

^[4] UNESP Sao Paulo State Univ, Dept Phys, IBILCE, BR-15054000 Sao Jose Do Rio Preto, SP - Brazil

^[5] Univ Sao Paulo, Dept Physiol & Biophys, Inst Biomed Sci, BR-05508900 Sao Paulo - Brazil

• Document type: Journal article
• Source: BIOCHEMISTRY; v. 51, n. 24, p. 4898-4908, JUN 19 2012.
• Web of Science Citations: 18

Abstract

This study shows that MP-1, a peptide from the venom of the Polybia paulista wasp, is more toxic to human leukemic T-lymphocytes than to human primary lymphocytes. By using model membranes and electrophysiology measurements to investigate the molecular mechanisms underlying this selective action, the porelike activity of MP-1 was identified with several bilayer compositions. The highest average conductance was found in bilayers formed by phosphatidylcholine or a mixture of phosphatidylcholine and phosphatidylserine (70:30). The presence of cholesterol or cardiolipin substantially decreases the MP-1 pore activity, suggesting that the membrane fluidity influences the mechanism of selective toxicity. The determination of partition coefficients from the anisotropy of Tip indicated higher coefficients for the anionic bilayers. The partition coefficients were found to be 1 order of magnitude smaller when the bilayers contain cholesterol or a mixture of cholesterol and sphingomyelin. The blue shift fluorescence, anisotropy values, and Stern-Volmer constants are indications of a deeper penetration of MP-1 into anionic bilayers than into zwitterionic bilayers. Our results indicate that MP-1 prefers to target leukemic cell membranes, and its toxicity is probably related to the induction of necrosis and not to DNA fragmentation. This mode of action can be interpreted considering a number of bilayer properties like fluidity, lipid charge, and domain formation. Cholesterol-containing bilayers are less fluid and less charged and have a tendency to form domains. In comparison to healthy cells, leukemic T-lymphocyte membranes are deprived of this lipid, resulting in decreased peptide binding and lower conductance. We showed that the higher content of anionic lipids increases the level of binding of the peptide to bilayers. Additionally, the absence of cholesterol resulted in enhanced pore activity. These findings may drive the selective toxicity of MP-1 to Jurkat cells. (AU)

• FAPESP's process: 06/57122-7 - Searching for lead compounds for rational development of new drugs and pesticides through bioprospecting in Brazilian arthropods
• Grantee: Mario Sergio Palma
• Support type: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 10/52077-9 - Molecular aspects of the voltage sensor of ionic channels: structure, kinetics and evolution
• Grantee: Manoel de Arcisio Miranda Filho
• Support type: Regular Research Grants
• FAPESP's process: 10/11823-0 - Mechanisms of interactions of lipid bilayers and amphiphilic substances of therapeutic interest
• Grantee: Marcia Perez dos Santos Cabrera
• Support type: Scholarships in Brazil - Post-Doctorate