Melatonin inhibits voltage-gated potassium K4.2 channels and negatively regulates melatonin secretion in rat pineal glands.

Melatonin is synthesized in and secreted from the pineal glands and regulates circadian rhythms. Although melatonin has been reported to modulate the activity of ion channels in several tissues, its effects on pineal ion channels remain unclear. In the present study, the effects of melatonin on voltage-gated K (K) channels, which play a role in regulating the resting membrane potential, were examined in rat pinealocytes.

Involvement of small-conductance Ca-activated K (SK2) channels in spontaneous Ca oscillations in rat pinealocytes.

Melatonin secretion from the pineal glands regulates circadian rhythms in mammals. Melatonin production is decreased by an increase in cytosolic Ca concentration following the activation of nicotinic acetylcholine receptors in parasympathetic systems. We previously reported that pineal Ca oscillations were regulated by voltage-dependent Ca channels and large-conductance Ca-activated K (BK) channels, which inhibited melatonin production.

Rh(III)-Catalyzed Reaction of α-Carbonyl Sulfoxonium Ylides and Alkenes: Synthesis of Indanones via [4 + 1] Cycloaddition.

The synthesis of indanone derivatives by the Rh(III)-catalyzed reaction of α-carbonyl sulfoxonium ylides with activated alkenes is reported. The reaction shows a high tolerance for functional groups and furnishes a variety of substituted indanone derivatives via a formal [4 + 1] cycloaddition. Highly stable sulfoxonium ylides were used as substrates in this C-H functionalization, and their bifunctional character could be effectively exploited using Rh(III) catalysis via sequential double C-C bond formation.

Induced pluripotent stem cell generation-associated point mutations arise during the initial stages of the conversion of these cells.

A large number of point mutations have been identified in induced pluripotent stem cell (iPSC) genomes to date. Whether these mutations are associated with iPSC generation is an important and controversial issue. In this study, we approached this critical issue in different ways, including an assessment of iPSCs versus embryonic stem cells (ESCs), and an investigation of variant allele frequencies and the heterogeneity of point mutations within a single iPSC clone.

Negligible immunogenicity of terminally differentiated cells derived from induced pluripotent or embryonic stem cells.

The advantages of using induced pluripotent stem cells (iPSCs) instead of embryonic stem (ES) cells in regenerative medicine centre around circumventing concerns about the ethics of using ES cells and the likelihood of immune rejection of ES-cell-derived tissues. However, partial reprogramming and genetic instabilities in iPSCs could elicit immune responses in transplant recipients even when iPSC-derived differentiated cells are transplanted. iPSCs are first differentiated into specific types of cells in vitro for subsequent transplantation.

Generation of genome integration-free induced pluripotent stem cells from fibroblasts of C57BL/6 mice without c-Myc transduction.

Although the induction of genome integration-free induced pluripotent stem cells (iPSCs) has been reported, c-Myc was still required for the efficient generation of these cells. Herein, we report mouse strain-dependent differences in the c-Myc dependence for iPSC generation and the successful generation of genome integration-free iPSCs without c-Myc transduction using C57BL/6 mouse embryonic fibroblasts. We performed 49 independent experiments and obtained a total of 24 iPSC clones, including 18 genome integration-free iPSC clones.

Conversion of ancestral fibroblasts to induced pluripotent stem cells.

The emergence of induced pluripotent stem cells (iPSCs) from an ancestral somatic cell is one of the most important processes underlying their generation, but the mechanism has yet to be identified. This is principally because these cells emerge at a low frequency, about 0.1% in the case of fibroblasts, and in a stochastic manner.