SynapseJ: An Automated, Synapse Identification Macro for ImageJ.

Autor:	Moreno Manrique JF; Department of Biology, Trinity University, San Antonio, TX, United States., Voit PR; Department of Biology, Trinity University, San Antonio, TX, United States., Windsor KE; Department of Biology, Trinity University, San Antonio, TX, United States., Karla AR; Department of Biology, Trinity University, San Antonio, TX, United States., Rodriguez SR; Department of Biology, Trinity University, San Antonio, TX, United States., Beaudoin GMJ 3rd; Department of Biology, Trinity University, San Antonio, TX, United States.
Jazyk:	angličtina
Zdroj:	Frontiers in neural circuits [Front Neural Circuits] 2021 Oct 04; Vol. 15, pp. 731333. Date of Electronic Publication: 2021 Oct 04 (Print Publication: 2021).
DOI:	10.3389/fncir.2021.731333
Abstrakt:	While electron microscopy represents the gold standard for detection of synapses, a number of limitations prevent its broad applicability. A key method for detecting synapses is immunostaining for markers of pre- and post-synaptic proteins, which can infer a synapse based upon the apposition of the two markers. While immunostaining and imaging techniques have improved to allow for identification of synapses in tissue, analysis and identification of these appositions are not facile, and there has been a lack of tools to accurately identify these appositions. Here, we delineate a macro that uses open-source and freely available ImageJ or FIJI for analysis of multichannel, z-stack confocal images. With use of a high magnification with a high NA objective, we outline two methods to identify puncta in either sparsely or densely labeled images. Puncta from each channel are used to eliminate non-apposed puncta and are subsequently linked with their cognate from the other channel. These methods are applied to analysis of a pre-synaptic marker, bassoon, with two different post-synaptic markers, gephyrin and N-methyl-d-aspartate (NMDA) receptor subunit 1 (NR1). Using gephyrin as an inhibitory, post-synaptic scaffolding protein, we identify inhibitory synapses in basolateral amygdala, central amygdala, arcuate and the ventromedial hypothalamus. Systematic variation of the settings identify the parameters most critical for this analysis. Identification of specifically overlapping puncta allows for correlation of morphometry data between each channel. Finally, we extend the analysis to only examine puncta overlapping with a cytoplasmic marker of specific cell types, a distinct advantage beyond electron microscopy. Bassoon puncta are restricted to virally transduced, pedunculopontine tegmental nucleus (PPN) axons expressing yellow fluorescent protein. NR1 puncta are restricted to tyrosine hydroxylase labeled dopaminergic neurons of the substantia nigra pars compacta (SNc). The macro identifies bassoon-NR1 overlap throughout the image, or those only restricted to the PPN-SNc connections. Thus, we have extended the available analysis tools that can be used to study synapses in situ . Our analysis code is freely available and open-source allowing for further innovation. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2021 Moreno Manrique, Voit, Windsor, Karla, Rodriguez and Beaudoin.)
Databáze:	MEDLINE
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