Biology subjects

Rivera-de-Torre, E.

Publications and source records attributed to Rivera-de-Torre, E..

3 recordsLinked to original sources

bioRxiv2024

The action mechanism of actinoporins revealed through the structure of pore-forming intermediates

Pore-forming proteins exemplify the transformative potential of biological molecules. Initially produced in a monomeric, water-soluble form, they spontaneously assemble into multimeric integral membrane proteins in the presence of suitable target lipids. Their functions include roles in apoptosis, cell signaling, immunity, as well as attack and defense systems between different organisms. This latter group encompasses actinoporins, a family of pore-forming toxins from sea anemones that kill target cells by perforating their plasma membrane. Here, we have determined the structures of two such toxins, fragaceatoxin C and sticholysin II, in a membrane environment using cryogenic electron microscopy. The structures reveal how dozens of lipid molecules interact in an orderly manner, forming an intrinsic part of the pore. We have also isolated different pore-forming intermediates, where only a fraction of the constituent monomers is incorporated, exhibiting non-closed, arc-shaped structures. Based on these structures we propose a mechanism of action where the sequential assembly of toxin monomers onto the membrane, accompanied by conformational changes, triggers pore formation and membrane perforation. Our results contribute to a better understanding of the transforming capacity of these pore-forming proteins, which are becoming increasingly important for their diverse biotechnological applications.

biochemistry↗

bioRxiv2024

mRNA-delivered consensus allergens induce a neutralizing IgG response against food and pollen allergens

Pollen-food allergy syndrome (PFAS) affects a significant proportion of the global population with a major health and socioeconomic impact. Patients are generally treated against the major sensitized allergen which does not warrant protection against cross-reactive allergens, leading to long and ineffective treatment regimens. For food allergies, patient guidelines rely on source avoidance, leading to dietary restrictions and reduced quality of life - in particular for those suffering from PFAS. To overcome these limitations, we introduce a novel allergy immunotherapy (AIT) approach utilizing consensus allergens and mRNA technology to achieve broader, safer, and faster desensitization in PFAS patients. We first designed a consensus allergen of orthologs of non-specific Lipid Transfer Proteins (cnsLTP-1) representing a broad spectrum of nsLTP allergens prevalent in food and pollen sources. CnsLTP-1 was delivered to naive BALB/c mice using mRNA-lipid nanoparticles (mRNA-LNP) as vehicle, or by a traditional protein formulation, to assess if it elicits broad protection against allergens from different sources. Immunization with both mRNA-LNP and protein formulations demonstrated that cnsLTP-1-specific IgGs could be induced, whilst the mRNA-LNP formulation notably avoided the induction of allergen-specific IgEs. The induced antibodies were capable of recognizing and binding to a variety of nsLTPs, and effectively blocked the binding of allergens by allergic patient serum IgEs. This study thus demonstrates that the presented AIT strategy, based on mRNA-LNP technology and consensus allergens, could find clinical utility by addressing the limitations of current AIT. Further development of this technology platform could pave the way for more effective and patient-friendly treatments for PFAS and other cross-reactive allergies.

bioengineering↗

bioRxiv2023

Discovery of broadly-neutralizing antibodies against brown recluse spider and Gadim scorpion sphingomyelinases using consensus toxins as antigens

Broadly-neutralizing monoclonal antibodies are becoming increasingly important tools for treating infectious diseases and animal envenomings. However, designing and developing broadly-neutralizing antibodies can be cumbersome using traditional low-throughput iterative protein engineering methods. Here, we present a new high-throughput approach for the standardized discovery of broadly-neutralizing monoclonal antibodies relying on phage display technology and consensus antigens representing an average sequence of related proteins. We showcase the utility of this approach by applying it to toxic sphingomyelinases from the venoms of very distant orders of the animal kingdom, the recluse spider and Gadim scorpion. First, we designed a consensus sphingomyelinase and performed three rounds of phage display selection, followed by DELFIA-based screening and ranking, and benchmarked this to a similar campaign involving cross-panning against recombinant versions of the native toxins. Second, we identified two scFvs that not only bind the consensus toxins, but which can also neutralize sphingomyelinase activity in vitro. Finally, we conclude that the phage display campaign involving the use of the consensus toxin was more successful in yielding cross-neutralizing scFvs than the phage display campaign involving cross-panning.

bioengineering↗