Nanobodies as novel potential drugs to target cardiac light chain amyloidosis

Autor: L Broggini, M Giono, V Speranzini, MM Barzago, G Palladini, L Diomede, C Pappone, S Ricagno
Rok vydání: 2022
Předmět:
Zdroj: Cardiovascular Research. 118
ISSN: 1755-3245
0008-6363
DOI: 10.1093/cvr/cvac066.233
Popis: Funding Acknowledgements Type of funding sources: Private hospital(s). Main funding source(s): IRCCS GRUPPO SAN DONATO Light chain amyloidosis (AL) is a systemic disease where fibrillar deposition of misfolded immunoglobulin light chains (LCs) severely affects organ functions. Cardiac involvement (75% of all AL cases) results in the worst prognosis for patients (1). Current AL therapies rely on repurposing of chemotherapeutic drugs targeting plasma cells as the source of LCs; however patients with cardiac damage are often too compromised to sustain such regiments. Alternative approaches aimed at destroying AL fibrils are being evaluated in clinical trials. Nevertheless, none of these treatments offer reliable solutions to counteract the life-threatening cardiac involvement in AL (2). Here, we propose an alternative approach targeting soluble toxic LCs: these immunoglobulin fragments are frequently overexpressed in patients with cardiac damage and have been found to exert toxicity to cardiac cells, making them an ideal candidate as new drug targets for cardiac AL (3). We combined a multidisciplinary approach to scout for and probe next generation AL drugs based on nanobodies designed to specifically bind soluble toxic LCs. Compared to conventional monoclonal antibodies, nanobodies consist of just two heavy chains, with a single variable domain (VHH, ~15kDa) as the antigen-binding region. These nanoscale VHHs can retain full antigen-binding potential upon isolation, establishing them as the smallest, naturally-derived antigen-binding fragment (4). To reach our aim, 11 different nanobodies against a cardiotoxic light chain (H3), derived from patient suffering from AL (5), were produced and characterized. To identify the most promising among the pool, a detailed characterization of the in vitro binding between H3 and each nanobody was performed, using a series of biophysical techniques, including isothermal titration calorimetry, microscale thermophoresis, bio-layer interferometry, and multi-angle light scattering. Notably, all the nanobodies efficiently bind to H3 forming stable complexes. Then, to investigate the capability of nanobodies to prevent H3 cardiotoxicity, we used the nematode C. elegans as in vivo model. Indeed, in C. elegans the administration of cardiotropic LCs causes a profound functional and structural damage on the pharynx, considered an "ancestral heart" (6). Interestingly, we found that some of our nanobodies prevented H3 from exerting its toxic activity, as their presences preserve nematode functional parameters. Collectively, our data pinpointed the novel potential role of nanobodies in the development of alternative treatments of AL patients with cardiac involvement.
Databáze: OpenAIRE
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