The primate-specific peptide Y-P30 regulates morphological maturation of neocortical dendritic spines

Abstract

The 30-amino acid peptide Y-P30 corresponds to the N-terminus of the primate-specific, sweat gland-derived dermcidin prepropeptide. Previous work has revealed that Y-P30 enhances the interaction of pleiotrophin and syndecans-2/3, and thus represents a natural ligand to study this signaling pathway. In immature neurons, Y-P30 activates the c-Src and p42/44 ERK kinase pathway, increases the amount of F-actin in axonal growth cones, and promotes neuronal survival, cell migration and axonal elongation. The action of Y-P30 on axonal growth requires syndecan-3 and heparan sulfate side chains. Whether Y-P30 has the potential to influence dendrites and dendritic protrusions has not been explored. The latter is suggested by the observations that syndecan-2 expression increases during postnatal development, that syndecan-2 becomes enriched in dendritic spines, and that overexpression of syndecan-2 in immature neurons results in a premature morphological maturation of dendritic spines. Here, analysing rat cortical pyramidal and non-pyramidal neurons in organotypic cultures, we show that Y-P30 does not alter the development of the dendritic arborization patterns. However, Y-P30 treatment decreases the density of apical, but not basal dendritic protrusions at the expense of the filopodia. Analysis of spine morphology revealed an unchanged mushroom/stubby-to-thin spine ratio and a shortening of the longest decile of dendritic protrusions. Whole-cell recordings from cortical principal neurons in dissociated cultures grown in the presence of Y-P30 demonstrated a decrease in the frequency of glutamatergic mEPSCs. Despite these differences in protrusion morphology and synaptic transmission, the latter likely attributable to presynaptic effects, calcium event rate and amplitude recorded in pyramidal neurons in organotypic cultures were not altered by Y-P30 treatment. Together, our data suggest that Y-P30 has the capacity to decelerate spinogenesis and to promote morphological, but not synaptic, maturation of dendritic protrusions.

GluN2B but Not GluN2A for Basal Dendritic Growth of Cortical Pyramidal Neurons

“…We have previously reported that GluN1, GluN2A, and GluN2B are expressed in OTC at DIV 5, DIV 10, and DIV 15-20 and the expression level of the three proteins increases with age (Engelhardt et al, 2018;Neumann et al, 2019). First, we confirmed that young neurons in OTC have functional NMDARs on the cell surface.…”

“…The developmental decrease of GluN2B protein is relative (Williams et al, 1993;Traynelis et al, 2010;Sanz-Clemente et al, 2013), and in fact the assembly of GluN1/GluN2B raises quite steadily until P20 in rat cortex as determined by immunoprecipitation (Babb et al, 2005) with surface expression of GluN2B being independent of activity. GluN2A protein increases strongly during the first postnatal week, and this proceeds also in OTC (Neumann et al, 2019). Given the presence of spontaneous activity, GluN2A efficiently replaces GluN2B in GluN2B-containing receptors at the cell surface (Barth and Malenka, 2001; Barria and Malinow, 2002).…”

“…Lysates and blots were performed as described (Engelhardt et al, 2018;Neumann et al, 2019) with OTC from 3 preparations that were exposed to ifenprodil, and allowed to recover from ifenprodil treatment for 12h and 24h. Using membrane strips placed over the molecular weight range of the target protein of interest several proteins of distinct kDa can be assessed per lysate.…”

Distinct Regulation of Bioenergetics and Translation by Group I mGluR and NMDAR

“…Since an optimal response to a stimulation depends on the spontaneous activity within the neuronal network [31], we recorded the spontaneous neurotransmission at the baseline of our high-density neuronal culture by whole-cell patch-clamp technique. The resting membrane potential and other passive membrane properties such as capacitance and input resistance values were comparable to previous reports ( Figure EV 1I ) [32–35]. The neurons fired bursts of matured action potential spontaneously detected both in the current-clamp and voltage-clamp mode ( Figure 1D and 1E ) at day in-vitro 15.…”

“…The action potential properties calculated through injecting a series of 500ms depolarizing current steps (−40pA to +540pA) were comparable to previously published reports ( Figure EV 1H, 1J, and 1K ) [33,34,36,37]. The presence of robust mEPSCs recorded at the baseline supports the presence of spontaneous excitatory neurotransmission ( Figure 1F and 1G ) [35]. Since the recording experiments were done with different batches of cultures, we sought to verify our observations in figure 1B in the same batch of cultures used for recording experiments.…”