FENIB (familial encephalopathy with neuroserpin inclusion bodies) is a genetic, protein-misfolding disease characterised by progressive neurodegeneration and dementia. FENIB is caused by mutations in neuroserpin (NS) that lead to its polymerisation and accumulation within the ER of neurons. To date, FENIB has been an incurable disease, mainly due to I) incomplete understanding of NS polymer structure and formation, II) poor insight on the mechanisms of polymer toxicity, and III) the lack of appropriate NS polymerisation inhibitors.
In recent years we have shed light on the structural and biophysical aspects of NS pathological conformers. In particular, we biophysically characterised the NS conformers and provided a model of polymer formation. Recently, we identified embelin (EMB) as the first (and only) low molecular weight compound inhibiting polymer formation and triggering polymer disaggregation in vitro.
Recent data indicate that N-glycosylation plays a key role in NS polymerisation, while non-glycosylated NS has been the standard for biochemical analyses so far; thus, during the past year we have been working to set up a system for the production of glycosylated NS (gNS).
We now propose:
i) to biochemically and biophysically characterize gNS in vitro, and
ii) exploit gNS for a new series of polymerisation and polymerization-inhibition assays coupled to inhibitor search/testing. To this end,
iii) we will perform a systematic chemical evolution approach starting from the EMB scaffold, and building on our preliminary results;
iv) in parallel, we will identify the gNS/EMB binding site, and develop a rational drug design search for improved inhibitors;
v) the most promising molecules will be tested in cell and mouse models of FENIB.
Taken together, these activities define the main aim of our project: a directed/rational search and production of synthetic inhibitors of NS polymerisation that are active in vitro and in vivo, based on a physiologically relevant gNS.