The enantiomer pair of 24S- and 24R-hydroxycholesterol differentially alter activity of large-conductance Ca -dependent K (slo1 BK) channel.

24S-hydroxycholesterol (HC) is most abundant oxysterols in the brain, passes through blood brain barrier, and is therefore regarded as an intermediary for brain cholesterol elimination. We reported that large-conductance Ca - and voltage-activated K (slo1 BK) channels are suppressed by this oxysterol, which is presumably intercalated into cell membrane to access the outer surface of the channel. Such an outer approach would make it difficult to interact with the inner, ion-conducting part of the channel.

24S-hydroxycholesterol alters activity of large-conductance Ca-dependent K (slo1 BK) channel through intercalation into plasma membrane.

Oxysterols, oxidization products of cholesterol, are regarded as bioactive lipids affecting various physiological functions. However, little is known of their effects on ion channels. Using inside-out patch clamp recording, we found that naturally occurring side-chain oxidized oxysterols, 20S‑hydroxycholesterol, 22R‑hydroxycholesterol, 24S‑hydroxycholestero, 25‑hydroxycholesterol, and 27‑hydroxycholesterol, induced current reduction of large-conductance Ca- and voltage-activated K (slo1 BK) channels heterologously expressed in HEK293T cells.

A2B5+/GFAP+ Cells of Rat Spinal Cord Share a Similar Lipid Profile with Progenitor Cells: A Comparative Lipidomic Study.

The central nervous system (CNS) harbors multiple glial fibrillary acidic protein (GFAP) expressing cell types. In addition to the most abundant cell type of the CNS, the astrocytes, various stem cells and progenitor cells also contain GFAP+ populations. Here, in order to distinguish between two types of GFAP expressing cells with or without the expression of the A2B5 antigens, we performed lipidomic analyses on A2B5+/GFAP+ and A2B5-/GFAP+ cells from rat spinal cord.

Learning impairment by minimal cortical injury in a mouse model of Alzheimer's disease.

Brain injury accelerates amyloid-β (Aβ) deposits and exacerbates Alzheimer's disease (AD). Accumulation of intracellular soluble Aβ impairs cognition prior to emergence of Aβ plaques. However, it is not known whether brain injury affects learning impairment attributable to intracellular soluble Aβ.

Omega-3 fatty acids lower blood pressure by directly activating large-conductance Ca²⁺-dependent K⁺ channels.

Long-chain polyunsaturated omega-3 fatty acids such as docosahexaenoic acid (DHA), found abundantly in oily fish, may have diverse health-promoting effects, potentially protecting the immune, nervous, and cardiovascular systems. However, the mechanisms underlying the purported health-promoting effects of DHA remain largely unclear, in part because molecular signaling pathways and effectors of DHA are only beginning to be revealed. In vascular smooth muscle cells, large-conductance Ca(2+)- and voltage-activated K(+) (BK) channels provide a critical vasodilatory influence.

Activity of BK(Ca) channel is modulated by membrane cholesterol content and association with Na+/K+-ATPase in human melanoma IGR39 cells.

Interaction of large conductance Ca(2+)- and voltage-activated K(+) (BK(Ca)) channels with Na(+)/K(+)-ATPase, caveolin-1, and cholesterol was studied in human melanoma IGR39 cells. Functional BK(Ca) channels were enriched in caveolin-rich and detergent-resistant membranes, i.e.

TLX activates MASH1 for induction of neuronal lineage commitment of adult hippocampal neuroprogenitors.

The orphan nuclear receptor TLX has been proposed to act as a repressor of cell cycle inhibitors to maintain the neural stem cells in an undifferentiated state, and prevents commitment into astrocyte lineages. However, little is known about the mechanism of TLX in neuronal lineage commitment and differentiation. A majority of adult rat hippocampus-derived progenitors (AHPs) cultured in the presence of FGF express a high level of TLX and a fraction of these cells also express the proneural gene MASH1.

Neuronal differentiation of neural progenitor cells by intracellular delivery of synthetic oligopeptide derived from Von Hippel-Lindau protein.

Intracellular delivery of synthetic oligopeptides has the potential to promote the occurrence of various cellular events such as cell death, proliferation, growth inhibition, metabolic changes, and morphological changes. However, the regulation of cellular differentiation by intracellular delivery of synthetic oligopeptides has been little studied. Von Hippel-Lindau protein (pVHL) is one of the proteins that functions to induce the differentiation of neural progenitor cells (NPCs).

Ca2+-activated K+ channels in human melanoma cells are up-regulated by hypoxia involving hypoxia-inducible factor-1alpha and the von Hippel-Lindau protein.

Under chronic hypoxia, tumour cells undergo adaptive changes involving hypoxia-inducible factors (HIFs). Here we report that ion currents mediated by Ca2+-activated K+ (K(Ca)) channels in human melanoma IGR1 cells are increased by chronic hypoxia (3% O2), as well as by hypoxia mimetics. This increase involves the HIF system as confirmed by overexpression of HIF-1alpha or the von Hippel-Lindau tumour suppressor gene.

Specific induction of neuronal cells from bone marrow stromal cells and application for autologous transplantation.

Bone marrow stromal cells (MSCs) have the capability under specific conditions of differentiating into various cell types such as osteocytes, chondrocytes, and adipocytes. Here we demonstrate a highly efficient and specific induction of cells with neuronal characteristics, without glial differentiation, from both rat and human MSCs using gene transfection with Notch intracellular domain (NICD) and subsequent treatment with bFGF, forskolin, and ciliary neurotrophic factor. MSCs expressed markers related to neural stem cells after transfection with NICD, and subsequent trophic factor administration induced neuronal cells.

Free-flow electrophoresis in a microfabricated chamber with a micromodule fraction separator. Continuous separation of proteins.

Continuous free flow electrophoresis of proteins was carried out in a microfabricated free flow electrophoresis (mFFE) module with the 30-microm thick slit of the separation. The newly developed micromodule fraction separator (MFS) was attached to the down-stream end site of the separation chamber of mFFE. By using the MFS, electrolyte solution from the separation chamber was introduced to the peristaltic pump without disturbing the electrolyte solution flow at the bottom side of the chamber.

Von Hippel-Lindau tumor suppressor protein transforms human neuroblastoma cells into functional neuron-like cells.

Von Hippel-Lindau (VHL) tumor suppressor protein is expressed in neurons of the central nervous system and plays an important role during the neuronal differentiation of central nervous system progenitor cells. To elucidate the neuronal differentiating potential of VHL protein in neuroblastoma cells, we overexpressed or inhibited VHL protein in human neuroblastoma cells (SY-SH5Y), and examined the morphological change, expressions of neuronal markers, and electrophysiological functions. Here we show that with VHL gene transduction SY-SH5Y cells stably expressing the VHL protein had neurite-like processes with varicosities, showed the distinct expression of the neuronal markers neuropeptide Y and neurofilament 200, acquired regulated neurosecretion competence in response to depolarizing and cholinergic stimuli, and had large voltage-gated fast sodium currents and delayed rectifier potassium (Kv) currents compatible with those of functional neurons.