Hydrogen sulfide potently promotes neuronal differentiation of adipose tissue-derived stem cells involving nitric oxide-mediated signaling cascade with the aid of cAMP-elevating agents.

Neuronal differentiation of adipose tissue-derived stem cells (ASCs) is potently promoted by valproic acid (VPA) through a gaseous signaling molecule, nitric oxide (NO). Here, we investigated the involvement of hydrogen sulfide (H2S), another gaseous signaling molecule, in neuronal differentiation of ASCs. VPA-promoted neuronal differentiation of ASCs was accompanied by increased intracellular H2S and sulfane sulfur with increased mRNA expression of enzymes synthesizing sulfane sulfur including cystathionine ß-synthase (CBS), of which inhibition reduced the differentiation efficiency. H2S donors, GYY4137 (GYY) or NaHS, potently promoted neuronal differentiation of ASCs when cAMP-elevating agents, dibutyryl cyclic adenosine monophosphate and isobutyl methyl-xanthine, were added as neuronal induction medium (NIM). Neuronal differentiation of ASCs promoted by NaHS or GYY was accompanied by Ca2+ entry and increased mRNA expression of voltage-gated Ca2+ channels. NaHS or GYY also increased mRNA expression of enzymes of the NO-citrulline cycle including inducible NO synthase (iNOS). It was concluded from these results that H2S potently promoted differentiation of ASCs into neuronal cells expressing functional voltage-gated Ca2+ channels with the aid of cAMP-elevating agents, involving NO-mediated signaling cascade. These effects of H2S were also considered as a partial mechanism for the VPA-promoted neuronal differentiation of ASCs.

Valproic acid promotes differentiation of adipose tissue-derived stem cells to neuronal cells selectively expressing functional N-type voltage-gated Ca2+ channels.

The differentiation of adipose tissue-derived stem cells (ASCs) to neuronal cells is greatly promoted by valproic acid (VPA), and is synergistically enhanced by the following treatment with neuronal induction medium (NIM) containing cAMP-elevating agents. In the present study, we investigated the synergism between VPA and NIM in neuronal differentiation of ASCs, assessed by the expression of neurofilament medium polypeptide (NeFM), with respect to Ca2+ entry. VPA (2 mM) treatment for 3 days followed by NIM for 2 h synergistically increased the incidence of neuronal cells differentiated from ASCs to an extent more than VPA alone treatment for 6 days, shortening the time required for the differentiation. VPA increased intracellular Ca2+ and the mRNAs of voltage-gated Ca2+ channels, Cacna1b (Cav2.2) and Cacna1h (Cav3.2), in ASCs. Inward currents through Ca2+ channels were evoked electrophysiologically at high voltage potential in ASCs treated with VPA. NIM reduced the mRNAs of NeFM and Cacna1b in VPA-promoted neuronal differentiation of ASCs. It was concluded that functional N-type voltage-gated Ca2+ channels (Cav2.2) are selectively expressed in VPA-promoted neuronal differentiation of ASCs. NIM seems to enhance the mRNA translation of molecules required for the differentiation. Neuronal cells obtained from ASCs by this protocol will be used as a cell source for regenerative therapy of neurological disorders associated with altered Cav2.2 activity.

Pyrolytic and non-pyrolytic boron nitride platforms in electrothermal AAS for the determination of cadmium in sea and estuarine water without chemical modification.

The analytical performance of pyrolytic and non-pyrolytic boron nitride (PBN and NBN) platforms, attached to a commercially available graphite tube furnace, in electrothermal atomic absorption spectrometry (ETAAS) for Cd was studied. Although the tolerable pyrolysis temperature was 300 degrees C with the conventional pyrolytic graphite platform, it increased to 600 and 950 degrees C with the PBN and NBN platforms, respectively. The lifetime of the ceramic platform was 500 firings. The NBN platform provided an enhanced sensitivity with a better reproducibility than others. Using the NBN platform allowed the LOD, based on the variability of the blank (3sigma), to be 0.1 microg l(-1) within a seawater matrix (20,000 mg NaCl l(-1)) and a constant sensitivity in the range 0-30,000 mg NaCl l(-1). Good recovery in the range of 90-105% was observed for Cd (2.0 microg l(-1)) spiked into sea, estuarine and river water samples using the recommended procedure. This work proposes that using the NBN platform allows the direct monitoring and control of contaminated water for Cd by ETAAS without any chemical modification.