Promoted neuronal differentiation after activation of alpha4/beta2 nicotinic acetylcholine receptors in undifferentiated neural progenitors.

BACKGROUND: Neural progenitor is a generic term used for undifferentiated cell populations of neural stem, neuronal progenitor and glial progenitor cells with abilities for proliferation and differentiation. We have shown functional expression of ionotropic N-methyl-D-aspartate (NMDA) and gamma-aminobutyrate type-A receptors endowed to positively and negatively regulate subsequent neuronal differentiation in undifferentiated neural progenitors, respectively. In this study, we attempted to evaluate the possible functional expression of nicotinic acetylcholine receptor (nAChR) by undifferentiated neural progenitors prepared from neocortex of embryonic rodent brains. METHODOLOGY/PRINCIPAL FINDINGS: Reverse transcription polymerase chain reaction analysis revealed mRNA expression of particular nAChR subunits in undifferentiated rat and mouse progenitors prepared before and after the culture with epidermal growth factor under floating conditions. Sustained exposure to nicotine significantly inhibited the formation of neurospheres composed of clustered proliferating cells and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction activity at a concentration range of 1 µM to 1 mM without affecting cell survival. In these rodent progenitors previously exposed to nicotine, marked promotion was invariably seen for subsequent differentiation into cells immunoreactive for a neuronal marker protein following the culture of dispersed cells under adherent conditions. Both effects of nicotine were significantly prevented by the heteromeric α4β2 nAChR subtype antagonists dihydro-β-erythroidine and 4-(5-ethoxy-3-pyridinyl)-N-methyl-(3E)-3-buten-1-amine, but not by the homomeric α7 nAChR subtype antagonist methyllycaconitine, in murine progenitors. Sustained exposure to nicotine preferentially increased the expression of Math1 among different basic helix-loop-helix proneural genes examined. In undifferentiated progenitors from embryonic mice defective of NMDA receptor subunit-1, nicotine was still effective in significantly inhibiting the proliferation. CONCLUSIONS/SIGNIFICANCE: Functional α4β2 nAChR subtype would be constitutively expressed to play a role in the mechanism underlying the determination of proliferation and subsequent differentiation fate into a neuronal lineage in association with preferential promotion of Math1 expression in undifferentiated neural progenitors of developing rodent neocortex independently of NMDA receptor activation

Surface Properties of Air-Exposed α-Ti–Pd Alloys via XPS and Cross-Coupling Reaction

To identify the reasons why Ti–Pd alloys for hydrogen storage materials show good hydrogenation properties, X-ray photoelectron spectroscopy and the Suzuki–Miyaura cross-coupling reaction were used to investigate a small amount of Pd added Ti–Pd alloys. Pd in or on Ti oxide films is in a valence state of 0 (Pd0). Catalytic activity was shown by Pd0 in the Suzuki–Miyaura cross-coupling reaction. Therefore, the enhanced hydrogenation properties of Ti–Pd alloys for hydrogen storage materials is due to Pd0\u27s catalytic activity in dissociating hydrogen molecules. In addition, the potential catalytic activity of Ti–Pd alloys was shown to be based on a Pd catalyst.This research was financially supported by the Japan Science and Technology Agency\u27s Matching PlannerProgram, the Kansai University Fund for Supporting Young Scholars (2015) and JSPS KAKENHI Grant Number 17K14837

Effects of nicotine on differentiation of mouse progenitors.

<p>(A) Cells were cultured with EGF in either the presence or absence of 10 µM nicotine, 10 µM DHβE, 10 µM TC2559 and 10 µM MLA for 10 days, followed by dispersion after removal of EGF and subsequent double immunocytochemistry analysis along with Hechst33342 staining for counting the number of immunoreactive cells. (B) Cells were cultured with EGF for 10 days in either the presence or absence of 10 µM nicotine, followed by extraction of total RNA and subsequent RT-PCR analysis on different bHLH genes. (C) Cells were cultured with EGF in either the presence or absence of 10 µM nicotine and 10 µM DHβE, followed by extraction of total RNA and subsequent RT-PCR analysis on <i>Math1</i> gene. *P<0.05, **P<0.01, significantly different from each control value obtained in cells not exposed to nicotine. ^##P<0.01, significantly different from the control value obtained in cells exposed to nicotine alone.</p

Neural progenitors prepared from NMDAR1-null mice.

<p>Neocortex was dissected from WT (NR1^+/+) and NMDAR1-null (NR1^−/−) mice, followed by culture with EGF for 10 days and subsequent determination of (A) the total size of neurospheres and (B) the number of individual immunoreactive cells on double immunocytochemistry analysis along with Hechst33342 staining. *P<0.05, **P<0.01, significantly different from the value obtained cells from WT mice. Cells from WT and NMDAR1-null mice were also cultured with EGF in either the presence or absence of 10 µM nicotine, 10 µM DHβE and 10 µM MLA for 10 days, followed by determination of (C) MTT reduction, (D) neurosphere size and (E) PI-positive dead cells. *P<0.05, **P<0.01, significantly different from each control value obtained in cells not exposed to nicotine. ^##P<0.01, significantly different from the control value obtained in cells exposed to nicotine alone.</p

Effects of nicotine on differentiation of rat progenitors.

<p>Cells were dispersed after the culture with EGF in either the presence or absence of 10 µM nicotine for 12 days, followed by further culture in (A) the absence and (B) presence of differentiation inducers such as ATRA and CNTF for an additional 6 days. Cells were then fixed for double immunocytochemical detection of both MAP2 and GFAP, followed by counting of the number of individual immunoreactive cells. *P<0.05, **P<0.01, significantly different from each control value obtained in cells not exposed to nicotine. ^##P<0.01, significantly different from the value obtained in cells exposed to nicotine alone.</p