Copper Modulates Adult Neurogenesis in Brain Subventricular Zone

Abstract

The subventricular zone (SVZ) in lateral ventricles is the largest neurogenic region in adult brain containing high amounts of copper (Cu). This study aims to define the role of Cu in adult neurogenesis by chelating labile Cu ions using a well-established Cu chelator D-Penicillamine (D-Pen). A neurosphere model derived from adult mouse SVZ tissues was established and characterized for its functionality with regards to neural stem/progenitor cells (NSPCs). Applying D-Pen in cultured neurospheres significantly reduced intracellular Cu levels and reversed the Cu-induced suppression of NSPC’s differentiation and migration. An in vivo intracerebroventricular (ICV) infusion model was subsequently established to infuse D-Pen directly into the lateral ventricle. Metal analyses revealed a selective reduction of Cu in SVZ by 13.1% (p = 0.19) and 21.4% (p < 0.05) following D-Pen infusions at low (0.075 μg/h) and high (0.75 μg/h) doses for 28 days, respectively, compared to saline-infused controls. Immunohistochemical studies revealed that the 7-day, low-dose D-Pen infusion significantly increased Ki67(+)/Nestin(+) cell counts in SVZ by 28% (p < 0.05). Quantification of BrdU(+)/doublecortin (DCX)(+) newborn neuroblasts in the rostral migration stream (RMS) and olfactory bulb (OB) further revealed that the short-term, low-dose D-Pen infusion, as compared with saline-infused controls, resulted in more newborn neuroblasts in OB, while the high-dose D-Pen infusion showed fewer newborn neuroblasts in OB but with more arrested in the RMS. Long-term (28-day) infusion revealed similar outcomes. The qPCR data from neurosphere experiments revealed altered expressions of mRNAs encoding key proteins known to regulate SVZ adult neurogenesis, including, but not limited to, Shh, Dlx2, and Slit1, in response to the changed Cu level in neurospheres. Further immunohistochemical data indicated that Cu chelation also altered the expression of high-affinity copper uptake protein 1 (CTR1) and metallothionein-3 (MT3) in the SVZ as well as CTR1 in the choroid plexus, a tissue regulating brain Cu homeostasis. Taken together, this study provides first-hand evidence that a high Cu level in SVZ appears likely to maintain the stability of adult neurogenesis in this neurogenic zone.

Grafting of electrically stimulated subventricular neural stem cells embedded in a nutritional hydrogel into the stroke cavity improved cell survival and behavioural recovery in mice

“…Understanding neural stem cell regulation is essential to improve our stem cell therapy for stroke for stroke [26]. Nestin and DCX are well known markers of cell proliferation in the SVZ [27]. In a recent study, it was shown that nestin is expandable in vitro and its expression persists in neurospheres grown in vitro after 7 days in culture derived from the subventricular zone of adult mice.…”

Choroid Plexus Modulates Subventricular Zone Adult Neurogenesis and Olfaction Through Secretion of Small Extracellular Vesicles

“…Primary neurospheres, which were formed 6 days after the initial seeding, were collected for Trypsin dissociation and the cell suspension was then reseeded into a 96-well U-shaped-bottom microplate (0.1 mL/well, 1.0 × 10 4 cells/mL in NBM enriched with growth factors and heparin) for secondary neurosphere formation. After 24 hrs, the secondary neurospheres were formed with nearly identical diameters (Liu et al 2022b). These secondary neurospheres were collected and resuspended in NBM for subsequent plating onto the PLO-coated glass bottom in the lower chamber.…”

“…qPCR was performed as previously described (Liu et al 2022b). Briefly, total RNA was extracted from samples using TRIzol reagent and Direct-zol RNA Microprep kit.…”

“…Immunocytochemistry was performed as previously described (Liu et al 2022b) to characterize the neurosphere growth and the impact of co-culture with CP tissues. Fixed neurosphere samples were blocked/permeabilized in PBST containing 5% normal goat serum and 0.3% TritonX-100.…”

“…The SVZ harbors neural stem/progenitor cells (NSPCs) and supplies newborn neurons to the olfactory bulb (OB) for normal olfaction (Lim and Alvarez-Buylla 2016). The interaction between the CP and SVZ has recently attracted attention due to the CP's regulation of NSPC dynamics in the adult brain (Lepko et al 2019;Liu et al 2022b;Planques et al 2019…”