CASPR2 autoimmune antibodies modify the developmental trajectory and network activity in human brain organoids

• Autor(a) principal: Oliveira, Ana Rafaela Gomes Soares
• Data de Publicação: 2023
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: http://hdl.handle.net/10362/159886
• topic: neurodevelopmental disorders; hiPSCs; reprogramming; human brain models; brain organoids; anti-CASPR2 antibodies; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

Recent decades have seen great expansion on our understanding on how neurons communicate and process information, however, limited access to human brain samples is a critical aspect preventing a greater understanding on the cellular and molecular mechanisms underlying brain diseases. Additionally, animal models and in vitro two-dimensional (2D) cell cultures fail to mimic the unique cellular and molecular physiology of the human brain. Recently, the development of human brain organoids has presented a new tool that may facilitate the study of functional human synapses and neuronal networks, that may further our understanding of disease mechanisms. Gestational transfer of brain-reactive antibodies is an important environmental risk factor triggering neurodevelopmental disorders. CASPR2 is encoded by CNTNAP2, an autism susceptibility gene and is a known target for pathogenic maternal autoantibodies that can interfere with fetal neurodevelopment. CASPR2 was originally described to be involved in the stabilization of voltage-gated potassium channels (Kv1.1 and Kv1.2) in myelinated axons, and later to have a role in earlier phases of rodent brain development. However, the effects induced by the presence of anti-CASPR2 antibodies (anti-CASPR2- Ab) during human brain development have not yet been addressed. To tackle this gap in knowledge we cultured human brain organoids for a period of up to 6-months in media containing human anti-CASPR2-Ab. We found that this challenge produced a decrease in CASPR2 and Contactin-2 protein levels, altered spontaneous synaptic activity, and led to an increase in the frequency of action potential firing upon current injection. These alterations were consistent with change in action potential kinetics, suggestive of altered function in voltage-gated potassium channels. In line with these observations, we also observed an overall increase in network activity in acute brain organoid slices. In parallel with this work, we also produced brain organoids from human induced pluripotent stem cells (hiPSCs) generated de novo from individuals carrying a genetic mutation associated with a neurological disease. The resulting mutated organoids recapitulated the genetic and molecular features of the original patients’ cells and offer a platform for further studying the mechanisms associated with the disease. Therefore, our data highlights the value of using brain organoids as robust models to study brain development and neurological disorders. These models may ultimately allow us to interpret the underlying neurobiological mechanisms associated with several disorders and lay the groundwork for identifying and testing novel therapeutic approaches.