Blocking phospholamban with VHH intrabodies enhances contractility and relaxation in heart failure
Erwin De Genst, Kylie S. Foo, Yao Xiao, Eduarde Rohner, Emma de Vries, Jesper Sohlmér, Nevin Witman, Alejandro Hidalgo, Terje R. Kolstad, William E. Louch, S. KENNETH PEHRSSON, Andrew Park, Yasuhiro Ikeda, Xidan Li, Lorenz M. Mayr, Kate F. Wickson, Karin Jennbacken, Kenny M. Hansson, Regina Fritsche‐Danielson, James Hunt, Kenneth R. Chien
Abstract
ATPase and its reversible inhibitor phospholamban, induces heart failure by inhibiting calcium cycling. While phospholamban is a bona-fide therapeutic target, approaches to selectively inhibit this protein remain elusive. Here, we report the in vivo application of intracellular acting antibodies (intrabodies), derived from the variable domain of camelid heavy-chain antibodies, to modulate the function of phospholamban. Using a synthetic VHH phage-display library, we identify intrabodies with high affinity and specificity for different conformational states of phospholamban. Rapid phenotypic screening, via modified mRNA transfection of primary cells and tissue, efficiently identifies the intrabody with most desirable features. Adeno-associated virus mediated delivery of this intrabody results in improvement of cardiac performance in a murine heart failure model. Our strategy for generating intrabodies to investigate cardiac disease combined with modified mRNA and adeno-associated virus screening could reveal unique future therapeutic opportunities.