Amyloid protein-misfolding diseases such as Alzheimer's (AD) and light chain amyloidosis (AL) remain intractable diseases with high morbidity and mortality. In AL, a plasma cell malignancy from clonal overproduction of immunoglobulin light chain proteins (LC) that misfold, and deposit in the heart, vessels and other tissues, median survival is 4 months if left untreated. AL is a malignancy that the VA recognizes as being related to Agent Orange exposure, pointing to its specific relevance in the veteran population. Chemotherapystem cell transplantation, the only treatment available, has high treatment- related mortality and incomplete success rate. We currently lack options to directly treat or protect cells against amyloid protein injury. Amyloid diseases (AL and AD) share common pathophysiology involving oxidative stress and apoptotic injury that occur early in microvessels and tissues exposed to soluble prefibrillar amyloid proteins (now recognized as a major path to injury). Nanoliposomes (NLs) are artificial phospholipid vesicles with a diameter of <100 nm that have great potential for treating amyloid protein disease. Unlike other nanoparticles, NLs are ideal for human treatment because they are non- toxic, non-immunogenic, fully biodegradable and structurally versatile. They can bind amyloid proteins with high affinity in vivo, reducing cell exposure to amyloid proteins. Their surface can be chemically modified to allow tissue targeting and intracellular and even organelle-specific delivery of therapeutic cargo. Among many therapeutic cargos that can be conjugated to NLs, clusterin (also known as apolipoprotein J) has promising potential to protect against amyloid protein cell injury. Clusterin is a constitutively expressed chaperone glycoprotein that has major dual roles of transporting abnormal proteins and is also an important pro-survival protein. It has abnormal metabolism in both AL and AD. Our overall goal is to test nanoliposome-based treatment of amyloid protein disease by developing and testing nanoliposomes alone (unconjugated) or functionalized with clusterin (conjugated) as protective agents against LC-induced toxicity to human vascular tissue. We will test the hypothesis that NLs composed of cholesterol, sphingomyelin (SM), phosphatidylcholine (PC) and phosphatidic acid (PA) will bind LC derived from AL patients thereby reducing toxicity to ex-vivo human adipose arterioles. Second, we will test the hypothesis that NLs functionalized to carry clusterin (both through non-covalent and covalent methods) will allow pericellular and intracellular delivery of clusterin that will also protect against LC injury. To test these hypotheses, in aim 1 we will develop NLs that will efficiently bind LC and quantify NLs' protective effect against LC induced toxicity.
In aim 2, we will develop functionalized NLs through conjugation with clusterin for use in intracellular clusterin delivery and test protective effect of conjugated NLs against LC toxicity. In both aims, we will probe key mechanisms underlying the protective effects of NLs. The proposal represents a novel approach to the treatment of amyloid protein disease using nanoparticles that might be useful for the treatment of veterans and patients with AL amyloidosis and other amyloid diseases such as Alzheimer's disease in the future.
Light chain amyloidosis is an often fatal disease and it is caused by the production and deposition of abnormal immunoglobulin light chain proteins in various organs such as the heart, blood vessels, and kidneys, gut and liver. It is one of the causes of heart failure. Among the Veteran population, it has also been linked to exposure to Agent Orange and other herbicides. There is currently no direct treatment to reverse the toxicity of light chain proteins. The project will develop nanoliposomes which are <100 nM artificial phospholipid vesicles that could reverse the injury induced by light chain proteins on human vascular tissue. The research may provide important new tools to address the toxicity of light chain proteins that may be useful in the future to improve the survival of patients with the disease. 1
