Julian M Menter
Morehouse School of Medicine, USA
Title: Some ground and excited state interactions among extracellular matrix, simple sugars and type I collagens in the dermis
Biography
Biography: Julian M Menter
Abstract
Dermal collagen and the surrounding extracellular matrix (ECM) have been described as the respective “bricks and mortar” of mammalian skin. Proteoglycans are glycosylated proteins with covalently attached anionic sulfated glycosaminoglycans (GAG). These in turn are attached to a hyaluronate (HA) backbone. Although the ECM macromolecules are best known for their architectural support of tissues, recent work indicates many other important cell functions. e.g. The ECM and collagen are both suscepible to environmental that can result in altered properties.
We have arbitarily divided the ECM into two sections (1) the collagen – PG complex itself, including the external membrane – bound PG, (e.g. aggrecans and decorin) and (2) the perturbations caused by the effects of the surrounding internal and external environment. Examples are age, mechanical loading, ECM disruption, internal and external effects of UV, temperature, and glycation by abnormal amounts of simple sugars.
We are interested in the effects of UV radiation on type I collagen. In simple in vitro work, UV causes collagen concomitant degradation and cross-linking that changes its basic properties and results in abnormal fibers, altered gelation and fluorescence properties, altered photochemical kinetics, and altered susceptibility to collagenase.
More recently, we have commenced a study of the effect of hyaluronate on collagen photochemistry. Using a model in vitro system of collagen - HA 1:2 mixtures For T < Tm ( ~36 C) HA retards the rate of photolysis by ~ 20 – 30 %. At T > Tm, where the coiled form predominates, there seems to be no such effect. Thus, stabilization of collagen helical structure seems to be one important function of the ECM. We envision further studies with added model proteoglycans.
References
1. JM Menter, L Freeman and O Edukuye (2015), Thermal and Photochemical Effects on the Fluorescence Properties of Type I Calf Skin Solutions at Physiological pH Open Journal of Physical Chemistry, 5, 21-27
2. JM Menter, AM Patta, RM Sayre, J Dowdy, and I Willis (2001). Effect of UV irradiation on Type I Collagen Fibril Formation in Neutral Collagen Solutions. Photodermatol. Photoimmunol. Photomed. 17:114-120.
3. J.M.Menter, L.M. Cornelison, L Cannick, A.M. Patta, J.C.Dowdy, R.M. Sayre, I.K. Abukhalaf, N.S. Silvestrov, and I. Willis. (2003) Effect of UV on the Susceptibility of Acid – Soluble Skh – 1 Hairless Mouse Collagen to Collagenase. Photochem. Photoimmunol. Photomed: 19 : 28 – 34
4. J. M. Menter (2006). Temperature Dependence of Collagen Fluorescence. Photochemical and Photobiological Sciences 5: 403 – 410.
5. J.M. Menter, I.K. Abukhalaf , A.M. Patta, N.A. Silvestrov, and I Willis (2007). Fluorescence of Putative Chromophores in Skh – 1 and Citrate – Soluble Calf Skin Collagens. Photochem. Photoimmunol. Photomed: 23 : 222 – 228.