Giovanni Meli

Amyloid Beta: conformational studies and subcellular targetingdetails-imagesre

A major line of research pursued in the lab, and pursued by Giovanni Meli, as a Junior Project Leader, is aimed at targeting Alzheimer' Amyloid-β (Aβ) peptide oligomers (AβOs) with recombinant intrabodies. A distinctive approach of Cattaneo's lab has been the use of antibodies as genes, rather than as proteins, which allows expressing them in different cells and in different compartments for silencing at the protein level (intrabodies). We isolate antibodies from ad hoc engineered libraries by the “Intracellular Antibody Capture Technology” (IACT), an approach that allows to address questions that cannot be by other silencing techniques, such as RNA interference.

We have undertaken the intrabody approach to dissect the cellular pathways leading to AβOs formation and actions.

Amyloid-β (Aβ) peptide, derived from abnormal processing of its APP precursor protein, is crucially involved in AD pathogenesis. In particular, soluble multimeric assemblies of Aβ, called Aβ oligomers (AβOs), are considered the most synaptotoxic Aβ species in the brains of AD patients and of AD transgenic mice models. Although increasing evidence supports the role of intracellular Aβ oligomerization and accumulation, as an early event in AD pathogenesis in humans and in transgenic mice, little is known about the intracellular processing and trafficking events of the different forms of AβOs.

Targeting the pathological assemblies of Aβ with specific probes, for mechanistic studies, for intracellular imaging or for therapeutic purposes, is therefore very important. Moreover, the intracellular targeting of AβOs would require the availability of antibody domains suitable for intracellular expression.

We have selected anti-AβOs recombinant antibody fragments (scFvs) that show unique properties in terms of sequence, epitope recognition, conformational selectivity, immunoreactivity towards naturally-produced Aβ deposits in AD brains, inhibition of synaptic binding of Aβ oligomers (ADDLs) and neutralization of their-induced cyto-toxicity These novel anti-AβOs are being expressed as intrabodies to study the subcellular traffic, dynamics and functions of AβOs.