FAIM Proteostasis in ALS - Summary
The broad, long term objectives of this project are to elucidate the mechanisms by which abnormal protein
aggregation is handled at the cellular level, and to determine the relationship between abnormal protein
aggregation/disaggregation and neurodegenerative disease. The specific focus of the present proposal is to
study the inter-relationships among a unique proteostatic agent (FAIM), abnormal protein aggregation, and
ALS disease. The clinical picture of ALS is grim, with motor neuron loss, progressive paralysis, and death,
all occurring during a brief course of 2-5 years duration. The etiology of ALS remains unknown, and no
inciting insult or preceding illness has been identified. Elucidation of ALS pathogenesis is hampered by the
sporadic nature of most cases, although a minority (familial ALS or FALS) is attributable to mutation in one
of several genes such as the gene encoding SOD1. Importantly, regardless of sporadic or familial origin, all
cases of ALS are characterized by the presence of abnormal protein aggregates. Because such aggregates
are known to be toxic, this dysfunctional protein behavior is thought to be a key pathogenic element in ALS.
It has been suggested that discovery of an agent that prevents or reverses protein aggregation could
constitute a means to ameliorate disease in ALS.
FAIM may be such an agent. Although originally cloned as Fas Apoptosis Inhibitory Molecule, we
recently reported that FAIM manifests important proteostatic activity. In the face of various forms of stress,
FAIM inhibits endogenous protein aggregation and, in keeping with this, FAIM counteracts loss of viability in
stressed cells and animals. Moreover, FAIM specifically inhibits aggregation of mutant SOD1 and disas-
sembles established mutant SOD1 aggregates in cell-free systems.
We now propose further study of FAIM in relation to ALS. 1) We will examine the capacity of FAIM to
influence aggregation of ALS-associated mutant SOD1 protein in human motor neuron cells differentiated
from healthy control iPSC in which FAIM has been deleted or overexpressed. 2) We will examine the
capacity of FAIM to improve ALS, by studying disease onset, severity and outcome, plus tissue histologic
examination, in mutant SOD1 ALS disease model mice in which FAIM has been deleted or overexpressed,
both generally and in neurons. These studies will likely show that FAIM can oppose mutant protein
aggregation in human neurons and can improve ALS disease in mice. Such results would provide proof-of-
principle and support for the hypothesis that FAIM can benefit other familial, and non-familial, forms of ALS
through its proteostatic activity. Further, such results would fuel important continued study of FAIM in
cellular stress conditions and in other neurodegenerative diseases. This work could suggest a potential
therapeutic role for FAIM in ameliorating ALS and possibly other neurodegenerative diseases.