Anti-NPTX2 (full length) polyclonal antibody

Memory loss in Alzheimers disease (AD) is attributed to pervasive weakening and loss of synapses. Here, we present findings supporting a special role for excitatory synapses connecting pyramidal neurons of the hippocampus and cortex with fast-spiking parvalbumin (PV) interneurons that control network excitability and rhythmicity. Excitatory synapses on PV interneurons are dependent on the AMPA receptor subunit GluA4, which is regulated by presynaptic expression of the synaptogenic immediate early gene NPTX2 by pyramidal neurons. In a mouse model of AD amyloidosis, Nptx2(-/-) results in reduced GluA4 expression, disrupted rhythmicity, and increased pyramidal neuron excitability. Postmortem human AD cortex shows profound reductions of NPTX2 and coordinate reductions of GluA4. NPTX2 in human CSF is reduced in subjects with AD and shows robust correlations with cognitive performance and hippocampal volume. These findings implicate failure of adaptive control of pyramidal neuron-PV circuits as a pathophysiological mechanism contributing to cognitive failure in AD.

Neuronal pentraxins (NPTX) and their corresponding receptors (NPTXR) have been studied as synapse-associated proteins in the nervous system, but their role in cancer is largely unknown. By applying a multidisciplinary, high-throughput proteomic approach, we have recently identified a peptide ligand motif for targeted drug delivery to neuroblastoma. Here, we report the sequence similarity between this peptide and a conserved portion of the pentraxin domain that is involved in the homo-and hetero-oligomerization of NPTX2 and NPTXR. We show that, in comparison with normal tissues, NPTX2 and NPTXR are overexpressed in vivo in mouse models, as well as in human Schwannian stroma-poor, stage IV neuroblastoma. Both proteins are concentrated in the vicinity of tumor blood vessels, with NPTXR also present on neuroblastic tumor cells. In vivo targeting ofNPTX2 and NPTXR with the selected peptide or with specific antibodies reduces tumor burden in orthotopic mouse models of human neuroblastoma. In vitro interference with this ligand/receptor system inhibits the organization of neuroblastoma cells in tumor-like masses in close contact with vascular cells, as well as their adhesion to normal microenvironment-derived cells, suggesting a role in the cross-talk between tumor and normal cells in the early steps of neuroblastoma development. Finally, we show that NPTX2 is a marker of poor prognosis for neuroblastoma patients. (C) 2015 AACR.