Pannexin 1 regulates postnatal neural stem and progenitor cell proliferation

Abstract

BackgroundPannexin 1 forms ion and metabolite permeable hexameric channels and is abundantly expressed in the brain. After discovering pannexin 1 expression in postnatal neural stem and progenitor cells we sought to elucidate its functional role in neuronal development.ResultsWe detected pannexin 1 in neural stem and progenitor cells in vitro and in vivo. We manipulated pannexin 1 expression and activity in Neuro2a neuroblastoma cells and primary postnatal neurosphere cultures to demonstrate that pannexin 1 regulates neural stem and progenitor cell proliferation likely through the release of adenosine triphosphate (ATP).ConclusionsPermeable to ATP, a potent autocrine/paracine signaling metabolite, pannexin 1 channels are ideally suited to influence the behavior of neural stem and progenitor cells. Here we demonstrate they play a robust role in the regulation of neural stem and progenitor cell proliferation. Endogenous postnatal neural stem and progenitor cells are crucial for normal brain health, and their numbers decline with age. Furthermore, these special cells are highly responsive to neurological injury and disease, and are gaining attention as putative targets for brain repair. Therefore, understanding the fundamental role of pannexin 1 channels in neural stem and progenitor cells is of critical importance for brain health and disease.

Analysis of a pannexin 2-pannexin 1 chimeric protein supports divergent roles for pannexin C-termini in cellular localization

“…Western blot analysis was performed as described (Wicki-Stordeur et al, 2012). Samples were homogenized in RIPA buffer (10 mM PBS [150 mM NaCl, 9.1 mM dibasic sodium phosphate, 1.7 mM monobasic sodium phosphate], 1% IGEPAL, 0.5% sodium deoxycholate, and 0.1% SDS) supplemented with protease inhibitor cocktail at 1 μ L/10 6 cells (stock: 0.104 mM 4-(2-aminoethyl)benzenesulfonyl fl uoride hydrochloride, 0.08 mM aprotinin, 4 mM bestatin hydrochloride, 1.4 mM N-(trans-epoxysuccinyl)-L-leucine 4-guanidinobutylamide, 2 mM leupeptin hemisulfate salt, and 1.5 mM pepstatin-A; Sigma-Aldrich), PMSF at 2 μ L/10 6 cells and 1 mM EDTA for 30 min and centrifuged for 20 min at 12,000 rpm to remove debris.…”

“…Hoechst 33342 was used as a nuclear counterstain. Confocal immunofl uorescence imaging was performed as described (Wicki-Stordeur et al, 2012) on Zeiss and Olympus confocal microscopes.…”

“…They have a predicted four-transmembrane domain structure, with intracellular N-and C-termini, and oligomerize into pore-forming multimers (Panx1 -hexamers and Panx2 -octamers; Ambrosi et al, 2010) in cellular membranes. Our laboratory is primarily interested in Panx1 and Panx2, which are both expressed in certain cells of the nervous system, including neural stem and progenitor cells, as well as in neural tumour cells such as neuroblastoma cells (see Swayne et al, 2010;Wicki-Stordeur et al, 2012 and recently reviewed by Penuela et al, 2012). Panx1 can be found in the plasma membrane (Chekeni et al, 2010) and/or in intracellular membranes (Vanden Abeele et al, 2006); its localization seems to depend on the cell-type.…”

Pannexin1 and Pannexin3 Exhibit Distinct Localization Patterns in Human Skin Appendages and are Regulated during Keratinocyte Differentiation and Carcinogenesis

“…In addition to the plasma membrane, Panx are also detected in the Golgi apparatus and in intracellular compartment such as the ER where they may function as intracellular Ca 2 ϩ -leak channel (D ' Hondt et al, 2011). There is now increasing evidence that Panx may play a role in long-range Ca 2 ϩ -wave propagation (Locovei et al, 2006b), vasodilatation (Locovei et al, 2006a), infl ammatory responses Surprenant, 2006, Silverman et al, 2009), postnatal neural stem and progenitor cell proliferation (Wicki-Stordeur et al, 2012), neuronal commitment (Swayne et al, 2010), ischemic death of neurons (Thompson et al, 2006) and death of enteric neurons during colitis (Gulbransen et al, 2012), epilepsy (Thompson et al, 2008), and apoptosis (Chekeni et al, 2010, Qu et al, 2011. A role for Panx1 and Panx2 in carcinogenesis has also been suggested (Lai et al, 2007(Lai et al, , 2009.…”

The more the merrier: The pannexin family just got a new branch (Comment on DOI 10.1002/bies.201100173)

“…A cursory look into the current crop of publications -in year 2012, alone -clearly demonstrates that novel study avenues are sprouting like the tentacles of an octopus. Pannexin 1 forms ion and metabolite permeable hexameric channels abundantly expressed in the brain where they regulate the proliferation of neural stem and progenitor cells [2]. In the colon, these channels are activated by inflammation that opens them up, thus, causing the death of the neurons and the loss of gut motility [3].…”