Compositional Effects on Phase Transition Behaviors of Myelin - PowerPoint PPT Presentation

Compositional Effects on Phase Transition Behaviors of Myelin Monolayers Antonio Ortiz, Ventura College Chemical Engineering Graduate Mentor: Younjin Min Faculty Advisor: J. Israelachvili & J. Zasadzinski UCSB Chemical Engineering Department

Myelin Sheath & Multiple Sclerosis (MS) Cause remains unknown • Treatments not fully effective • Structure, composition, & • interactions of healthy myelin not fully understood Studying these characteristics • should lead to the advancem ent of finding cure … Healthy Myelin Diseased Myelin

Research Goals Mechanism by which MS develops not understood therefore research will be fundamental in nature: Myelin composed of 7 constituents • Pick two of those components and study the • stability/ instability of lipid mixtures of various mole ratios: -Isotherm Experiments (In Progress) -Confocal Microscopy (Coming Soon!!!) Lipids studied this Summer: 1) Cholesterol (CHOL), Bovine 2) Phosphatidylethanolamine (PE), Porcine

Why CHOL & PE ? • CHOL most abundant component • PE known to show adhesive forces in myelin multilayer • Ultimately few Research Studies done with CHOL and PE MW 746.06 MW 386.66 Cholesterol PE

Isotherm Experiments � Employs Langmuir Trough � MOPS Buffer pH 7.2 imitates physiological environments Pressure Movable Sensor Barrier � Place sample… and compress � Computer collects data MOPS Buffer Solution

COLLAPSE!!! Phase Transitions

Data CHOL:PE 60 50 Surface Pressure (mN/m) CHOL:PE 1:0 40 CHOL:PE 0:1 30 CHOL:PE 0.50:0.50 CHOL:PE 0.85:0.15 20 CHOL:PE 0.15:0.85 10 0 0 20 40 60 80 100 120 -10 Molecular Area(A^2 /mol)

Data (Con’t) � Pure CHOL collapses much quicker than pure PE � Lipid Mixtures take on characteristics of BOTH pure lipids � Data gives us something to compare to REAL myelin composition

Summary of Achievements • Identified a lipid that potentially could reinforce integrity of myelin • Different Mole Ratios than Previously Studied Tested all nine lipid mixtures • Adds to the foundation on which we can build on.

Future Plans o Conduct many isotherms to be able to compare to real myelin lipid compositions o Different Temperatures (+ / - Body Temperature) o Confocal Microscopy

Acknowledgements Jens & Dr. Nick, INSET • Younjin Min, Mentor • Prajna Dhar, Step-Mentor • “Joe’s Group” • THANK YOU!!!