Porphyromonas gingivalis lipopolysaccharide rapidly activates trigeminal sensory neurons and may contribute to pulpal pain.

AIM: To determine whether Porphyromonas gingivalis lipopolysaccharide (LPS) can directly activate trigeminal neurons, to identify which receptors are involved and to establish whether activation leads to secretion of the neuropeptide calcitonin gene-related peptide (CGRP) and/or the translocation of NF-κB. METHODOLOGY: Mouse trigeminal ganglion (TG) cells were cultured in vitro for 2 days. The effect of P. gingivalis LPS (20 µg mL-1 ) on calcium signalling was assessed (by calcium imaging using Cal-520 AM) in comparison with the transient receptor potential channel A1 (TRPA1) agonist cinnamaldehyde (CA; 100 µmol L-1 ), the TRP channel V1 (TRPV1) agonist capsaicin (CAP; 1 µmol L-1 ) and high potassium (60 mmol L-1 KCl). TG cultures were pre-treated with either 1 µmol L-1 CLI-095 to block Toll-like receptor 4 (TLR4) signalling or with 3 µmol L-1 HC-030031 to block TRPA1 signalling. CGRP release was determined using ELISA, and nuclear translocation of NF-κB was investigated using immunocytochemistry. Data were analysed by one-way analysis of variance, followed by Bonferroni's post hoc test as appropriate. RESULTS: Porphyromonas gingivalis LPS directly exerted a rapid excitatory response on sensory neurons and non-neuronal cells (P < 0.001 to P < 0.05). The effects on neurons appear to be mediated via TLR4- and TRPA1-dependent pathways. The responses were accompanied by an increased release of CGRP (P < 0.001) and by NF-κB nuclear translocation (P < 0.01). CONCLUSIONS: Porphyromonas gingivalis LPS directly activated trigeminal sensory neurons (via TLR4 and TRPA1 receptors) and non-neuronal cells, resulting in CGRP release and NF-κB nuclear translocation. This indicates that P. gingivalis can directly influence activity in trigeminal sensory neurons and this may contribute to acute and chronic inflammatory pain.

CRISPR-based gene editing enables FOXP3 gene repair in IPEX patient cells.

The prototypical genetic autoimmune disease is immune dysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome, a severe pediatric disease with limited treatment options. IPEX syndrome is caused by mutations in the forkhead box protein 3 (FOXP3) gene, which plays a critical role in immune regulation. As a monogenic disease, IPEX is an ideal candidate for a therapeutic approach in which autologous hematopoietic stem and progenitor (HSPC) cells or T cells are gene edited ex vivo and reinfused. Here, we describe a CRISPR-based gene correction permitting regulated expression of FOXP3 protein. We demonstrate that gene editing preserves HSPC differentiation potential, and that edited regulatory and effector T cells maintain their in vitro phenotype and function. Additionally, we show that this strategy is suitable for IPEX patient cells with diverse mutations. These results demonstrate the feasibility of gene correction, which will be instrumental for the development of therapeutic approaches for other genetic autoimmune diseases.

Repetitive Ca2+ spikes in a unicellular green alga.

Cytosolic Ca2+ activity ([Ca2+]cy) and membrane potential were measured simultaneously in the unicellular green alga Eremosphaera viridis. Steady state [Ca2+]cy was about 160 nM. A 'light-off' stimulus induced a transient elevation of [Ca2+]cy ([Ca2+]cy spike) in parallel with a transient hyperpolarization of the plasma membrane. Caffeine and Sr2+, known to release Ca2+ from intracellular stores in animal cells, induced repetitive [Ca2+]cy spikes in Eremosphaera which were always accompanied by parallel repetitive transient hyperpolarizations. These transient hyperpolarizations could be used as an indicator for [Ca2+]cy spikes. Repetitive [Ca2+]cy spikes in Eremosphaera were similar to repetitive [Ca2+]cy spikes in excitable animal cells. The mechanisms underlying these [Ca2+]cy oscillations seem to be comparable in animal and plant cells.

Voltage- and Ca2+-dependent burst generation in neuroendocrine Dahlgren cells in the teleost Platichthys flesus.

The neuroendocrine Type 1 Dahlgren cells of the caudal neurosecretory system of the flounder display characteristic bursting activity, which may increase secretion efficiency. The firing activity pattern in these cells was voltage-dependent; when progressively depolarized, cells moved from silent (approximately -70 mV), through bursting and phasic to tonic firing (< -65 mV). Brief (10 s) evoked bursts of spikes were followed by a slow after-depolarization (ADP; amplitude up to 10 mV, duration 10-200 s), which was also voltage-dependent and could trigger a prolonged burst. The ADP was significantly reduced in the absence of external Ca(2+) ions or the presence of the L-type Ca(2+) channel blocker, nifedipine. BayK 8644 (which increases L-type channel open times) significantly increased ADP duration, whereas the Ca(2+)-activated nonselective cation channel blocker, flufenamic acid, had no effect. Pharmacological blockade of Ca(2+)-activated K(+) channels, using apamin and charybdotoxin, increased the duration of both ADP and evoked bursts. However, action potential waveform was unaffected by either apamin/charybdotoxin, nifedipine, BayK 8644 or removal of external Ca(2+). The short duration (approximately 100 ms), hyperpolarization-activated, postspike depolarizing afterpotentials (DAP), were significantly reduced by nifedipine. We propose that long duration ADPs underlie bursts and that short duration DAPs play a role in modulation of spike frequency.

Altered expression of the voltage-gated calcium channel subunit α2δ-1: a comparison between two experimental models of epilepsy and a sensory nerve ligation model of neuropathic pain.

The auxiliary α2δ-1 subunit of voltage-gated calcium channels is up-regulated in dorsal root ganglion neurons following peripheral somatosensory nerve damage, in several animal models of neuropathic pain. The α2δ-1 protein has a mainly presynaptic localization, where it is associated with the calcium channels involved in neurotransmitter release. Relevant to the present study, α2δ-1 has been shown to be the therapeutic target of the gabapentinoid drugs in their alleviation of neuropathic pain. These drugs are also used in the treatment of certain epilepsies. In this study we therefore examined whether the level or distribution of α2δ-1 was altered in the hippocampus following experimental induction of epileptic seizures in rats, using both the kainic acid model of human temporal lobe epilepsy, in which status epilepticus is induced, and the tetanus toxin model in which status epilepticus is not involved. The main finding of this study is that we did not identify somatic overexpression of α2δ-1 in hippocampal neurons in either of the epilepsy models, unlike the upregulation of α2δ-1 that occurs following peripheral nerve damage to both somatosensory and motor neurons. However, we did observe local reorganization of α2δ-1 immunostaining in the hippocampus only in the kainic acid model, where it was associated with areas of neuronal cell loss, as indicated by absence of NeuN immunostaining, dendritic loss, as identified by areas where microtubule-associated protein-2 immunostaining was missing, and reactive gliosis, determined by regions of strong OX42 staining.

Effect of Prepodyne as a perineal cleansing agent for clean catch specimens.

In a study to determine a safe cleansing agent for collection of midstream urine specimens, 35 pregnant women (25 experimental subjects who cleansed the periurethal area three times with Prepodyne and 10 control subjects who did not cleanse the area), Prepodyne was found to be satisfactory. Although iodine was detected in the urine of women who used Prepodyne, the amount was not in sufficient quantity to alter bacterial colony counts or to inhibit growth.

Differential expression and regulation of K(+) channels in the maize coleoptile: molecular and biophysical analysis of cells isolated from cortex and vasculature.

UNLABELLED: Recently, two K(+) channel genes, ZMK1 and ZMK2, were isolated from maize coleoptiles. They are expressed in the cortex and vasculature, respectively. Expression in Xenopus oocytes characterized ZMK1 as an inwardly rectifying K(+) channel activated by external acidification, while ZMK2 mediates voltage-independent and proton-inhibited K(+) currents. In search of the related gene products in planta, we applied the patch-clamp technique to protoplasts isolated from the cortex and vasculature of Zea mays coleoptiles and mesocotyls. In the cortex, a 6-8 pS K(+) channel gave rise to inwardly rectifying K(+) currents. Like ZMK1, this channel was activated by apoplastic acidification. In contrast, protoplasts from vascular tissue expressing the sucrose transporter ZmSUT1 were dominated by largely voltage-independent K(+) currents with a single-channel conductance of 22 pS. The pronounced sensitivity to the extracellular protons Ca(2+), Cs(+) and Ba(2+) is reminiscent of ZMK2 properties in oocytes. Thus, the dominant K(+) channels in cortex and vasculature most likely represent the gene products of ZMK1 and ZMK2. Our studies on the ZMK2-like channels represent the first in planta analysis of a K+ channel that shares properties with the AKT3 K(+) channel family. KEYWORDS: K(+) channel, voltage-independent, proton block, maize coleoptile.

Aluminum activates a citrate-permeable anion channel in the aluminum-sensitive zone of the maize root apex. A comparison between an aluminum- sensitive and an aluminum-resistant cultivar.

In search for the cellular and molecular basis for differences in aluminum (Al) resistance between maize (Zea mays) cultivars we applied the patch-clamp technique to protoplasts isolated from the apical root cortex of two maize cultivars differing in Al resistance. Measurements were performed on protoplasts from two apical root zones: The 1- to 2-mm zone (DTZ), described as most Al-sensitive, and the main elongation zone (3-5 mm), the site of Al-induced inhibition of cell elongation. Al stimulated citrate and malate efflux from intact root apices, revealing cultivar differences. In the elongation zone, anion channels were not observed in the absence and presence of Al. Preincubation of intact roots with 90 microM Al for 1 h induced a citrate- and malate-permeable, large conductance anion channel in 80% of the DTZ protoplasts from the resistant cultivar, but only 30% from the sensitive cultivar. When Al was applied to the protoplasts in the whole-cell configuration, anion currents were elicited within 10 min in the resistant cultivar only. La3+ was not able to replace or counteract with Al3+ in the activation of this channel. In the presence of the anion-channel blockers, niflumic acid and 4, 4'-dinitrostilbene-2, 2'disulfonic acid, anion currents as well as exudation rates were strongly inhibited. Application of cycloheximide did not affect the Al response, suggesting that the channel is activated through post-translational modifications. We propose that the Al-activated large anion channel described here contributes to enhanced genotypical Al resistance by facilitating the exudation of organic acid anions from the DTZ of the maize root apex.

Auxin-induced K+ channel expression represents an essential step in coleoptile growth and gravitropism.

Auxin-induced growth of coleoptiles depends on the presence of potassium and is suppressed by K+ channel blockers. To evaluate the role of K+ channels in auxin-mediated growth, we isolated and functionally expressed ZMK1 and ZMK2 (Zea mays K+ channel 1 and 2), two potassium channels from maize coleoptiles. In growth experiments, the time course of auxin-induced expression of ZMK1 coincided with the kinetics of coleoptile elongation. Upon gravistimulation of maize seedlings, ZMK1 expression followed the gravitropic-induced auxin redistribution. K+ channel expression increased even before a bending of the coleoptile was observed. The transcript level of ZMK2, expressed in vascular tissue, was not affected by auxin. In patch-clamp studies on coleoptile protoplasts, auxin increased K+ channel density while leaving channel properties unaffected. Thus, we conclude that coleoptile growth depends on the transcriptional up-regulation of ZMK1, an inwardly rectifying K+ channel expressed in the nonvascular tissue of this organ.