**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
M. Alejandra Tricerri, Instituto de Investigaciones Bioquímicas de La Plata Dr. Prof Rodolfo R. Brenner, (INIBIOLP), La Plata, Buenos Aires, Argentina

**Main Body of the Abstract**
The extracellular matrix (ECM) is a complex tridimensional scaffold that actively participates in physiological and pathological events. The objective of this study was to test whether structural proteins of the ECM and glycosaminoglycans (GAGs) may favor the retention of human apolipoprotein A-I (apoA-I) variants associated with amyloidosis and atherosclerosis. Biopolymeric matrices containing collagen type I (Col, a main macromolecular component of the ECM) with or without heparin (Hep, a model of GAGs) were constructed and characterized, and used to compare the binding of apoA-I having the native sequence (Wt) or Arg173Pro, a natural variant inducing cardiac amyloidosis. Protein binding was observed by fluorescence microscopy and unbound proteins quantified by a colorimetric assay.
We observed that both, Wt and Arg173Pro bound to the scaffolds containing Col, but the presence of Hep diminished the binding efficiency. Col-Hep matrices retained Arg173Pro more than the Wt. The retained protein was only partially removed from the matrices with saline solutions, indicating that electrostatic interactions may occur but are not the main driving force. Using in addition thermodynamic molecular simulations and size exclusion chromatography approaches, we suggest that the binding of apoA-I variants to the biopolymeric matrices is driven by many low affinity interactions.
We conclude that under this scenario Col-Hep scaffolds contribute to the binding of Arg173Pro, as a cooperative platform which could modify the native protein conformation affecting protein folding. We show that the composition of the ECM may be key to the protein retention before the deposition as amyloid fibers.



Interactions of variants of human apolipoprotein A-I with biopolymeric model matrices. Effect of collagen and heparin. OC18 (#155)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.