Sodium butyrate decreases histamine-stimulated calcium mobilization in C6 glioma cells

Increasing histone acetylation of cloned embryos, but not donor cells, by sodium butyrate improves their in vitro development in pigs

Previous studies have demonstrated that increased histone acetylation in donor cells or cloned embryos, by applying a histone deacetylase inhibitor (HDACi) such as trichostatin A (TSA), significantly enhances their developmental competence. However, its effect may vary with the type of HDACi and the target species, with some research showing nonsignificant or detrimental effects of TSA on in vitro and in vivo development of embryos. In this study, we show that sodium salt of butyric acid, a short-chain fatty acid produced naturally in the body by bacterial degradation of dietary fibers in the colon and rectum, increases histone acetylation in pig fibroblast and embryos at a concentration of 1.0 and 5.0 mM, respectively. However, treatment of donor cells with NaBu did not affect the rate of blastocyst formation or embryo quality in terms of histone acetylation and total nuclei per blastocyst (p > 0.05). On the contrary, treatment of cloned pig embryos with NaBu for 4 h significantly enhanced (p < 0.01) the rate of blastocyst formation (18.3 +/- 2.1 vs. 11.2 +/- 3.0%), although the total nuclei number per blastocyst did not differ. More importantly, blastocysts generated from NaBu-treated cloned embryos had increased levels of histone acetylation that was comparable to those of in vitro fertilized (IVF) embryos (36.7 +/- 3.6 vs. 45.9 +/- 2.5). In conclusion, our data suggest that histone hyperacetylation by NaBu treatment of cloned embryos, but not donor cell, enhances their in vitro development up to blastocyst stage.

Role of Ca2+ in induction of neurotransmitter-related gene expression by butyrate

We examined the effect of butyrate on neurotransmitter-related gene expression and calcium homeostasis in PC12 cells. Pretreatment with Ca2+ chelators (EGTA or BAPTA-AM) attenuated the butyrate-triggered accumulation of TH and ppEnk mRNA indicating that Ca2+ plays a role in butyrate-induced regulation of neuronal genes. Butyrate alone did not alter intracellular Ca2+ levels as determined by Fura-PE3 fluorescence; however, pretreatment with butyrate (18-24 h) reduced the first Ca2+ peak and prevented the second sustained rise in [Ca2+]i as induced by nicotine or ryanodine. In contrast, butyrate had no effect on Ca2+ transients when added shortly before or during nicotine or ryanodine stimulation. These results suggest that chronic butyrate exposure can modulate cell responses by affecting intracellular Ca2+ signaling.

ATP-stimulated Ca2+ influx and phospholipase D activities of a rat brain-derived type-2 astrocyte cell line, RBA-2, are mediated through P2X7 receptors

This study characterizes and examines the P2 receptor-mediated signal transduction pathway of a rat brain-derived type 2 astrocyte cell line, RBA-2. ATP induced Ca2+ influx and activated phospholipase D (PLD). The ATP-stimulated Ca2+ influx was inhibited by pretreating cells with P2 receptor antagonist, pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), in a concentration-dependent manner. The agonist 2'- and 3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate (BzATP) stimulated the largest increases in intracellular Ca2+ concentrations ([Ca2+]i); ATP, 2-methylthioadenosine triphosphate tetrasodium, and ATPgammaS were much less effective, whereas UTP, ADP, alpha,beta-methylene-ATP, and beta,gamma-methylene-ATP were ineffective. Furthermore, removal of extracellular Mg2+ enhanced the ATP- and BzATP-stimulated increases in [Ca2+]i. BzATP stimulated PLD in a concentration- and time-dependent manner that could be abolished by removal of extracellular Ca2+ and was inhibited by suramin, PPADS, and oxidized ATP. In addition, PLD activities were activated by the Ca2+ mobilization agent, ionomycin, in an extracellular Ca2+ concentration-dependent manner. Both staurosporine and prolonged phorbol ester treatment inhibited BzATP-stimulated PLD activity. Taken together, these data indicate that activation of the P2X7 receptors induces Ca2+ influx and stimulates a Ca2+-dependent PLD in RBA-2 astrocytes. Furthermore, protein kinase C regulates this PLD.