WIS-NeuroMath enables versatile high throughput analyses of neuronal processes.

Automated analyses of neuronal morphology are important for quantifying connectivity and circuitry in vivo, as well as in high content imaging of primary neuron cultures. The currently available tools for quantification of neuronal morphology either are highly expensive commercial packages or cannot provide automated image quantifications at single cell resolution. Here, we describe a new software package called WIS-NeuroMath, which fills this gap and provides solutions for automated measurement of neuronal processes in both in vivo and in vitro preparations. Diverse image types can be analyzed without any preprocessing, enabling automated and accurate detection of neurites followed by their quantification in a number of application modules. A cell morphology module detects cell bodies and attached neurites, providing information on neurite length, number of branches, cell body area, and other parameters for each cell. A neurite length module provides a solution for images lacking cell bodies, such as tissue sections. Finally, a ganglion explant module quantifies outgrowth by identifying neurites at different distances from the ganglion. Quantification of a diverse series of preparations with WIS-NeuroMath provided data that were well matched with parallel analyses of the same preparations in established software packages such as MetaXpress or NeuronJ. The capabilities of WIS-NeuroMath are demonstrated in a range of applications, including in dissociated and explant cultures and histological analyses on thin and whole-mount sections. WIS-NeuroMath is freely available to academic users, providing a versatile and cost-effective range of solutions for quantifying neurite growth, branching, regeneration, or degeneration under different experimental paradigms.

Axonal degeneration is regulated by the apoptotic machinery or a NAD+-sensitive pathway in insects and mammals.

Selective degeneration of neuronal projections and neurite pruning are critical for establishment and maintenance of functional neural circuits in both insects and mammals. However, the molecular mechanisms that govern developmental neurite pruning versus injury-induced neurite degeneration are still mostly unclear. Here, we show that the effector caspases 6 and 3 are both expressed within axons and that, on trophic deprivation, they exhibit distinct modes of activation. Surprisingly, inhibition of caspases is not sufficient for axonal protection and a parallel modulation of a NAD(+)-sensitive pathway is required. The proapoptotic protein BAX is a key element in both pathways as its genetic ablation protected sensory axons against developmental degeneration both in vitro and in vivo. Last, we demonstrate that both pathways are also involved in developmental dendritic pruning in Drosophila. More specifically, the mouse Wld(S) (Wallerian degeneration slow) protein, which is mainly composed of the full-length sequence of the NAD(+) biosynthetic Nmnat1 enzyme, can suppress dendritic pruning in C4da (class IV dendritic arborization) sensory neurons in parallel to the fly effector caspases. These findings indicate that two distinct autodestruction pathways act separately or in concert to regulate developmental neurite pruning.