Level Of Depolarization Research Articles

Synthesis of novel hydrophilic celastrol nanoformulation by entrapment within calcium phosphate nanoparticle and study of its antioxidant activity against neurotoxin-induced damage in human neuroblastoma cells

Celastrol, a pentacyclic triterpenoid found in Chinese herb Tripterygium wilfordii, is considered as one of the top-five natural medicinal compounds with high antioxidant property. However, celastrol has poor aqueous solubility and thereby low bioavailability, restricting its clinical application as drug. To overcome this problem, we nanonized celastrol by entrapping it within hydrophilic nanocarrier – calcium phosphate nanoparticle. The synthesized calcium phosphate celastrol nanoparticle (CPCN) had average size of 35 nm, spherical shape, significant stability with (−) 37 mV zeta potential, celastrol entrapment efficiency around 75 % and low celastrol release kinetics spanning over 7 days, as measured by different techniques like FESEM, AFM, DLS, and spectrophotometry. Studies on the antioxidant potency of CPCN by flow cytometry and fluorescence microscopy depicted that the toxicity developed in human neuroblastoma cells SH-SY5Y by treatment with the selective neurotoxin MPP+ iodide (N-Methyl-4-phenylpyridinium iodide) got reduced by pretreatment of the cells with CPCN. Determination of cellular ROS content, depolarization level of mitochondrial membrane potential, cell cycle analysis and nuclear damage in MPP+-exposed cells demonstrated that CPCN had about 65 % more antioxidant efficacy over that of bulk celastrol. Thus, the nanonization process transformed hydrophobic celastrol into hydrophilic CPCN, having high potentiality to be developed as an effective antioxidant drug.

LOFAR Deep Fields: Probing the sub-mJy regime of polarized extragalactic sources in ELAIS-N1. I. The catalog

Quantifying the number density and physical characteristics of extragalactic polarized sources is important for the successful planning of future studies based on Faraday rotation measure (RM) grids of polarized sources to probe foreground Galactic and intergalactic magnetic fields. However, it is proving very hard to detect polarized signal from the population of very faint (sub-mJy) polarized sources at low radio frequencies, and their properties are mostly unknown. LOFAR can play an important role in such studies thanks to its sensitivity and angular resolution, combined with the precision on the inferred RM values that can be achieved through low-frequency broad-band polarimetry. The aim of this study is to probe the sub-mJy polarized source population with LOFAR. In this first paper, we present the method used to stack LOFAR polarization datasets, the resulting catalog of polarized sources, and the derived polarized source counts. The European Large Area ISO Survey-North 1 (ELAIS-N1) field, one of the deepest of the LOFAR Two-Metre Sky Survey (LoTSS) Deep Fields so far, was selected for a polarimetric study at 114.9–177.4 MHz. A total area of 25 deg$^2$ was imaged at 6"-resolution in the Stokes $Q$ and $U$ parameters. Alignment of polarization angles was done both in frequency and in Faraday space before stacking datasets from 19 eight-hour-long epochs taken in two different LOFAR observing cycles. A search for polarized sources was carried out in the final, stacked dataset, and the properties of the detected sources were examined. The depolarization level of sources known to be polarized at 1.4 GHz was quantified. A one-sigma noise level, $ QU $, of 19 mu Jy/beam was reached in the central part of the field after stacking. Twenty-five polarized sources were detected above 8$ QU $, five of which had not been detected in polarization at any other radio frequencies before. Seven additional polarized components were found by lowering the threshold to 6$ QU $ at positions corresponding to sources known to be polarized at 1.4 GHz. In two radio galaxies, polarization was detected from both radio lobes, so the final number of associated radio continuum sources is 31. The detected sources are weakly polarized, with a median degree of polarization of 1.75<!PCT!> for the sample of sources detected in polarized emission. For the 10 polarized sources previously identified in a pilot LOFAR study of the ELAIS-N1 field at 20"-resolution, the RM values are consistent but the degrees of polarization are higher in the 6"-resolution data. The sources previously detected in polarization at 1.4 GHz are significantly depolarized at 150 MHz. The catalog is used to derive the polarized source counts at 150 MHz. This is the deepest and highest-resolution polarization study at 150 MHz to date. A full characterization of the sources and an analysis of the catalog will be presented in Paper II.

The LiaSR Two-Component System Regulates Resistance to Chlorhexidine in Streptococcus mutans.

Chlorhexidine (CHX) is widely considered to be the gold standard for preventing dental caries. However, it is possible to induce resistance to CHX. The LiaSR two-component system has been identified that contributed to CHX resistance in Streptococcus mutans, which is one of the major pathogens in dental caries. However, the underlying mechanisms remain unclear. In this study, an MIC assay and a viability assessment demonstrated that after deleting the liaS and liaR genes, the sensitivity of mutants could increase. The Nile Red efflux assay exhibited that the efflux rates of mutants were significantly decreased. The RT-qPCR results indicated that the LiaSR two-component system-mediating influence on the expression of lmrB in S. mutans contributed to the efflux rate. The hydrophobicity assay and membrane potential assay showed that the mutants had higher levels of hydrophobicity and depolarization, suggesting that their membranes were more easily disturbed. The TEM graphs revealed that the border of the cell membrane was unclear in mutants compared with the wild-type strain, indicating that the cell envelope's stress response may have been inhibited. While the surface charge of mutants showed no significant difference in the wild-type strain according to the result of cytochrome c-based charged determination. This study provides valuable novel insights into the mechanisms of the LiaSR two-component system in the CHX resistance of S. mutans.

Changes in arterial myocyte excitability induced by subarachnoid hemorrhage in a rat model

Aneurismal subarachnoid hemorrhage (aSAH) is a neurovascular disease produced by the rupture of the cerebral arteries and the extravasation of blood to the subarachnoid space and is accompanied by severe comorbidities. Secondarily associated vasospasm is one of the main side effects after hydrocephalus and possible rebleeding. Here, we analyze the alterations in function in the arteries of a rat model of SAH.For this, autologous blood was injected into the cisterna magna. We performed electrophysiological, microfluorimetric, and molecular biology experiments at different times after SAH to determine the functional and molecular changes induced by the hemorrhage. Our results confirmed that in SAH animals, arterial myocytes were depolarized on days 5 and 7, had higher [Ca2+]i on baseline, peaks and plateaus, and were more excitable at low levels of depolarization on day 7, than in the control and sham animals. Microarray analysis showed that, on day 7, the sets of genes related to voltage-dependent Ca2+ channels and K+ dynamics in SAH animals decreased, while the voltage-independent Ca2+ dynamics genes were over-represented. In conclusion, after SAH, several mechanisms involved in arterial reactivity were altered in our animal model, suggesting that there is no unique cause of vasospasm and alterations in several signaling pathways are involved in its development.

Striated preferentially expressed gene deficiency leads to mitochondrial dysfunction in developing cardiomyocytes.

A deficiency of striatedpreferentially expressed gene (Speg), a member of the myosin light chain kinase family, results in abnormal myofibril structure and function of immature cardiomyocytes (CMs), corresponding with a dilated cardiomyopathy, heart failure and perinatal death. Mitochondrial development plays a role in cardiomyocyte maturation. Therefore, this study investigated whether Speg deficiency ( - / - ) in CMs would result in mitochondrial abnormalities. Speg wild-type and Speg-/- C57BL/6 littermate mice were utilized for assessment of mitochondrial structure by transmission electron and confocal microscopies. Speg was expressed in the first and second heart fields at embryonic (E) day 7.5, prior to the expression of mitochondrial Na+/Ca2+/Li+ exchanger (NCLX) at E8.5. Decreases in NCLX expression (E11.5) and the mitochondrial-to-nuclear DNA ratio (E13.5) were observed in Speg-/- hearts. Imaging of E18.5 Speg-/- hearts revealed abnormal mitochondrial cristae, corresponding with decreased ATP production in cells fed glucose or palmitate, increased levels of mitochondrial superoxide and depolarization of mitochondrial membrane potential. Interestingly, phosphorylated (p) PGC-1α, a key mediator of mitochondrial development, was significantly reduced in Speg-/- hearts during screening for targeted genes. Besides Z-line expression, Speg partially co-localized with PGC-1α in the sarcomeric region and was found in the same complex by co-immunoprecipitation. Overexpression of a Speg internal serine/threonine kinase domain in Speg-/- CMs promoted translocation of pPGC-1α into the nucleus, and restored ATP production that was abolished by siRNA-mediated silencing of PGC-1α. Our results demonstrate a critical role of Speg in mitochondrial development and energy metabolism in CMs, mediated in part by phosphorylation of PGC-1α.

Vagus Nerve Stimulation Provides Neuroprotection Against Doxorubicin‐induced Chemobrain Via Activations of Both Muscarinic and Nicotinic Acetylcholine Receptors

AbstractBackgroundChemotherapy, particularly treatment with doxorubicin (Dox), is known to cause neurotoxicity in the brain known as chemobrain. Dox administration causes neuroinflammation, mitochondrial dysfunction, and subsequent cognitive decline (1). Additionally, cancer survivors who received Dox were found to have an increased risk of developing dementia (2). Interestingly, the activation of the parasympathetic nervous system by vagus nerve stimulation (VNS) exerted neuroprotective effects on Alzheimer’s disease (3). However, the neuroprotective effects of VNS against Dox‐induced chemobrain have never been investigated. Moreover, whether the therapeutic effects of VNS are achieved via stimulation of nicotinic acetylcholine receptors (AChRs) or muscarinic acetylcholine receptors (mAChRs) needs further investigation.MethodTwenty male Wistar rats were divided into sham‐operated and VNS device‐implanted groups. After 2 weeks of recovery, all sham‐operated rats were divided and received either 0.9% NSS (Control; n = 4) or 3 mg/kg Dox for 6 doses (Sham; n = 4) via intraperitoneal injection. In addition, all VNS device‐implanted rats were treated with 3 mg/kg Dox for 6 doses and then randomly divided into 3 groups to receive either 0.9% NSS (VNS; n = 4), a mAChR antagonist (atropine; 1 mg/kg/day, VNS+Atro; n = 4), or a nAChR antagonist (mecamylamine; 7.5 mg/kg/day, VNS+Mec; n = 4). At the end of treatment protocol, cognitive function was assessed using the novel object location (NOL) task. The brains were obtained for further molecular studies.ResultDox treatment impaired cognitive performance in rats, as demonstrated by a decrease in the preference index in the NOL task (Figure A). Microglia in the CA1 region of Dox‐treated rats exhibited decreased process complexity and increased microglial volume, indicating reactivation of microglia (Figure B and C). Notably, Dox administration caused mitochondrial dysfunction in the brain, as evidenced by increased levels of mitochondrial reactive oxygen species (ROS) and mitochondrial membrane depolarization (Figure D and E). Importantly, the intervention with VNS rescued long‐term cognitive function in Dox‐treated rats by ameliorating all chemobrain pathologies (Figure A‐E). In contrast, the therapeutic effects of VNS were completely abolished by blocking either mAChRs or nAChRs using their antagonists (Figure A‐E).ConclusionThe findings suggested that VNS protected against Dox‐induced chemobrain through activations of both nAChRs and mAChRs.

Silver(I) Bromide Phosphines Induce Mitochondrial-Mediated Apoptosis in Malignant Human Colorectal Cells.

Due to its emerging resistance to current therapies, colon cancer remains one of the most difficult types of cancer to treat. Silver, a non-invasive metal, is well-known for its antimicrobial and anti-cancer properties. Two novel silver(I) phosphine complexes, [silver(I) diphenyl-2-pyridylphosphine]Br (1) and [silver(I) is 4-(dimethylamino)phenyldiphenylphosphine]Br (2), were synthesized and characterized by elemental analysis, infrared spectroscopy, and nuclear magnetic resonance (1H, 13C, 31P). To assess the complexes' potentials as antiproliferative agents, experiments were conducted on human colorectal cancer cells (HT-29) in vitro. The evaluation involved the analysis of morphological changes, the performance of an alamarBlue® proliferation assay, and the undertaking of flow cytometric analyses to detect mitochondrial alterations. Complex 1 displayed superior selectivity and significant inhibitory effects on malignant HT-29 cells while exhibiting minimal toxicity towards two non-malignant HEK-293 and MRHF cells. Moreover, after 24 h of treatment, complex 1 (IC50, 7.49 µM) demonstrated higher efficacy in inhibiting cell proliferation compared with complex 2 (IC50, 21.75 µM) and CDDP (IC50, 200.96 µM). Flow cytometric studies indicated that complex 1 induced regulated cell death, likely through mitochondrial-mediated apoptosis. Treatment with complex 1 induced morphological changes indicative of apoptosis, which includes membrane blebbing, PS externalization, increased levels of reactive oxygen species (ROS) and mitochondrial membrane depolarization (ΔΨm). These observations suggest that complex 1 targets the mitochondria and holds promise as a novel metal-based anti-cancer therapeutic for the selective treatment of colorectal cancer.

History of electrophysiological research from “Animal Electricity” by L. Galvani to electrical potentials by V. Chagovts

The development of physiology as an independent science is closely related to electrophysiology. The regularities formulated in this section are important for understanding the regularities of the functioning of internal organs. The section of electrophysiology includes the study of excitability processes, the formation of rest and action potentials, the mechanisms of muscle contraction, the conduction of excitation along nerve fibers, the mechanisms of conduction of excitation through synapses. The work of all internal organs is based on electrophysiological principles, since excitable tissues are part of the functioning internal organs. Both students of medical universities and working doctors will find it useful to get acquainted with this material, which determines the relevance of the work. We set the aim of the article is to analise the historical stages in the formation of electrophysiology as an independent section of physiology. Metodology of the study is realized mainly with the help of descriptive and historical methods. The novelty of the study. The article states that the presence of “animal electricity” was first noticed by Luigi Galvani. Further studies conducted by Volt, Matteucci, Dubois-Raymond expanded the understanding of the mechanisms of conducting excitations on the neuromuscular elements of the body. Attention is drawn to the role of Ukrainian physiologists who made an important contribution to the scientific heritage. Thus, V. Chagovts discovered the fundamental laws of potential formation and the basis of excitability, the concept of a critical level of depolarization. Conclusions. The resulting patterns are fundamental even today. The data presented in the article expand knowledge of the physiology of excitable tissues and provide an opportunity to form a more complete picture from this section.

Mechanisms of initiation of cortical spreading depression

BackgroundThere is increasing evidence from human and animal studies that cortical spreading depression (CSD) is the neurophysiological correlate of migraine aura and a trigger of migraine pain mechanisms. The mechanisms of initiation of CSD in the brain of migraineurs remain unknown, and the mechanisms of initiation of experimentally induced CSD in normally metabolizing brain tissue remain incompletely understood and controversial. Here, we investigated the mechanisms of CSD initiation by focal application of KCl in mouse cerebral cortex slices.MethodsHigh KCl puffs of increasing duration up to the threshold duration eliciting a CSD were applied on layer 2/3 whilst the membrane potential of a pyramidal neuron located very close to the site of KCl application and the intrinsic optic signal were simultaneously recorded. This was done before and after the application of a specific blocker of either NMDA or AMPA glutamate receptors (NMDARs, AMPARs) or voltage-gated Ca2+ (CaV) channels. If the drug blocked CSD, stimuli up to 12–15 times the threshold were applied.ResultsBlocking either NMDARs with MK-801 or CaV channels with Ni2+ completely inhibited CSD initiation by both CSD threshold and largely suprathreshold KCl stimuli. Inhibiting AMPARs with NBQX was without effect on the CSD threshold and velocity. Analysis of the CSD subthreshold and threshold neuronal depolarizations in control conditions and in the presence of MK-801 or Ni2+ revealed that the mechanism underlying ignition of CSD by a threshold stimulus (and not by a just subthreshold stimulus) is the CaV-dependent activation of a threshold level of NMDARs (and/or of channels whose opening depends on the latter). The delay of several seconds with which this occurs underlies the delay of CSD initiation relative to the rapid neuronal depolarization produced by KCl.ConclusionsBoth NMDARs and CaV channels are necessary for CSD initiation, which is not determined by the extracellular K+ or neuronal depolarization levels per se, but requires the CaV-dependent activation of a threshold level of NMDARs. This occurs with a delay of several seconds relative to the rapid depolarization produced by the KCl stimulus. Our data give insights into potential mechanisms of CSD initiation in migraine.

Downregulation of TRPM7, TRPM8, and TRPV1 channels modulate apoptotic parameters and neurodegenerative markers: Focus on neuronal differentiation and Parkinson's disease model

The transient receptor potential channel (TRP) channels are expressed in neuronal tissues and involved in neurological diseases such as pain, epilepsy, neuronal apoptosis, and neurodegenerative diseases. Formerly, we have investigated how neuronal differentiation changes TRP channels expression profile and how Parkinson's disease model is related with this expression levels. We have found that transient receptor potential channel melastatin subtype 7 (TRPM7), transient receptor potential channel melastatin subtype 8 and transient receptor potential channel vanilloid subtype 1 (TRPV1) channels have pivotal effects on differentiation and 1-Methyl-4-phenylpyridinium (MPP+ )-induced Parkinson's disease model in SH-SY5Y cells. In this study, we have investigated that downregulation of the TRP channels to evaluate how differentiation status changes to Parkinson's disease pathological hallmarks. We have also performed to other analyses to elucidate these TRP channels' function in MPP+ -induced neurotoxicity related apoptosis, cell viability, caspase 3 and 9 enzyme activities, intracellular reactive oxygen species production, mitochondrial depolarization levels, Ca2+ signaling, Alpha-synuclein and Dopamine levels, mono amino oxidase A and B enzymatic activities, both in differentiated and undifferentiated neuronal cells. Herein we have concluded that especially TRPM7 and TRPV1 channels have distinct role in Parkinson's disease pathology via their activity changings in pathological state, and downregulation of these channels or specific antagonists can be useful for the possible treatment strategy for Parkinson's disease and related markers.

Rutin Attenuates Oxidative Stress Via PHB2-Mediated Mitophagy in MPP+-Induced SH-SY5Y Cells.

Oxidative stress plays a crucial role in the occurrence and development of Parkinson's disease (PD). Rutin, a natural botanical ingredient, has been shown to have antioxidant properties. Therefore, the aim of this study was to investigate the neuroprotective effects of rutin on PD and the underlying mechanisms. MPP+(1-methyl-4-phenylpyridinium ions)-treated SH-SY5Y cells were used as an in vitro model of PD. Human PHB2-shRNA lentiviral particles were transfected into SH-SY5Y cells to interfere with the expression of Prohibitin2 (PHB2). The oxidative damage of cells was analyzed by detecting intracellular reactive oxygen species (ROS), malondialdehyde (MDA), and mitochondrial membrane potential (MMP). Western blotting was used to detect the protein expression of antioxidant factors such as nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NADPH quinone oxidoreductase-1 (NQO-1), and mitophagy factors PHB2, translocase of outer mitochondrial membrane 20 (TOM20), and LC3II/LC3I (microtubule-associated protein II light chain 3 (LC3II) to microtubule-associated protein I light chain 3 (LC3I)). In addition, we also examined the expression of PHB2 and LC3II/LC3I by immunofluorescence staining. MPP+ treatment significantly increased the generation of ROS and MDA and the level of MMP depolarization and decreased the protein expression of Nrf2, HO-1, NQO1, TOM20, PHB2, and LC3II/LC3I. In MPP+-treated SH-SY5Y cells, rutin significantly decreased the generation of ROS and MDA and the level of MMP depolarization and increased the protein expression of Nrf2, HO-1, NQO-1, TOM20, PHB2, and LC3II/LC3I. However, the protective role of rutin was inhibited in PHB2-silenced cells. Rutin attenuates oxidative damage which may be associated with PHB2-mediated mitophagy in MPP+-induced SH-SY5Y cells. Rutin might be used as a potential drug for the prevention and treatment of PD.

Cec4-Derived Peptide Inhibits Planktonic and Biofilm-Associated Methicillin Resistant Staphylococcus epidermidis.

Staphylococcus epidermidis is part of the normal microbiota that colonizes the skin and mucosal surfaces of human beings. Previous studies suggested that S. epidermidis possessed low virulence, but recent studies confirmed that it can acquire high virulence from Staphylococcus aureus and with the increasing detection of methicillin-resistant S. epidermidis. It has become a major pathogen of graft-associated and hospital-acquired infections. In previous studies, we modified the antimicrobial peptide Cec4 (41 amino acids) and obtained the derived peptide C9 (16 amino acids) showing better antimicrobial activity against S. epidermidis with an MIC value of 8 μg/mL. The peptide has rapid bactericidal activity without detectable high-level resistance, showing certain inhibition and eradication ability on S. epidermidis biofilms. The damage of cell membrane structures by C9 was observed by scanning emission microscopy (SEM) and transmission electron microscopy (TEM). In addition, C9 altered the S. epidermidis cell membrane permeability, depolarization levels, fluidity, and reactive oxygen species (ROS) accumulation and possessed the ability to bind genomic DNA. Analysis of the transcriptional profiles of C9-treated cells revealed changes in genes involved in cell wall and ribosome biosynthesis, membrane protein transport, oxidative stress, and DNA transcription regulation. At the same time, the median lethal dose of C9 in mice was more than 128 mg/kg, and the intraperitoneal administration of 64 mg/kg was less toxic to the liver and kidneys of mice. Furthermore, C9 also showed a certain therapeutic effect on the mouse bacteremia model. In conclusion, C9 may be a candidate drug against S. epidermidis, which has the potential to be further developed as an antibacterial therapeutic agent. IMPORTANCE S. epidermidis is one of the most important pathogens of graft-related infection and hospital-acquired infection. The growing problem of antibiotic resistance, as well as the emergence of bacterial pathogenicity, highlights the need for antimicrobials with new modes of action. Antimicrobial peptides have been extensively studied over the past 30 years as ideal alternatives to antibiotics, and we report here that the derived peptide C9 is characterized by rapid bactericidal and antibiofilm activity, avoiding the development of resistance by acting on multiple nonspecific targets of the cell membrane or cell components. In addition, it has therapeutic potential against S. epidermidis infection in vivo. This study provides a rationale for the further development and application of C9 as an effective candidate antibiotic.

Apoptosis in platelets is independent of the actin cytoskeleton.

Homeostasis between platelet production and clearance is essential for human health. A critical facet of the balance that facilitates platelet clearance from the circulation is apoptosis (programmed cell death). The precise cellular mechanisms that underpin platelet apoptosis are not defined. In nucleated cells, reorganization of the actin cytoskeleton is known to regulate platelet apoptosis. However, the role of the actin cytoskeleton in regulating apoptosis in platelets has not been extensively studied as they are anucleate and exhibit a distinctive physiology. Here, apoptosis was induced in washed human platelets using ABT-737, a BH3-mimetic drug. Mitochondrial depolarization was measured using the ratiometric dye JC-1; surface phosphatidylserine (PS) exposure was measured by annexin V binding; caspase-3 activation was measured by Western blotting. All three apoptotic markers were unaffected by the presence of either the actin depolymerizing drug cytochalasin D or the actin polymerizing drug jasplakinolide. Moreover, platelets were isolated from wild-type (WT) mice and mice deficient in gelsolin (Gsn), an actin-binding protein that is essential for normal cytoskeletal remodeling. In response to ABT-737, gelsolin-null (Gsn-/-) platelets initially showed accelerated PS exposure relative to WT platelets, however, both WT and Gsn-/- platelets exhibited similar levels of mitochondrial depolarization and caspase-3 activation in response to ABT-737. We conclude that ABT-737 induces established markers of platelet apoptosis in an actin-independent manner.

Presynaptic Acetylcholine Receptors Modulate the Time Course of Action Potential-Evoked Acetylcholine Quanta Secretion at Neuromuscular Junctions.

For effective transmission of excitation in neuromuscular junctions, the postsynaptic response amplitude must exceed a critical level of depolarization to trigger action potential spreading along the muscle-fiber membrane. At the presynaptic level, the end-plate potential amplitude depends not only on the acetylcholine quanta number released from the nerve terminals in response to the nerve impulse but also on a degree of synchronicity of quanta releases. The time course of stimulus-phasic synchronous quanta secretion is modulated by many extra- and intracellular factors. One of the pathways to regulate the neurosecretion kinetics of acetylcholine quanta is an activation of presynaptic autoreceptors. This review discusses the contribution of acetylcholine presynaptic receptors to the control of the kinetics of evoked acetylcholine release from nerve terminals at the neuromuscular junctions. The timing characteristics of neurotransmitter release is nowadays considered an essential factor determining the plasticity and efficacy of synaptic transmission.

Network States Classification based on Local Field Potential Recordings in the Awake Mouse Neocortex.

Recent studies using intracellular recordings in awake behaving mice revealed that cortical network states, defined based on membrane potential features, modulate sensory responses and perceptual outcomes. Single-cell intracellular recordings are difficult and have low yield compared to extracellular recordings of population signals, such as local field potentials (LFPs). However, it is currently unclear how to identify these behaviorally-relevant network states from the LFP. We used simultaneous LFP and intracellular recordings in the somatosensory cortex of awake mice to design a network state classification from the LFP, the Network State Index (NSI). We used the NSI to analyze the relationship between single-cell (intracellular) and population (LFP) signals over different network states of wakefulness. We found that graded levels of population signal faithfully predicted the levels of single-cell depolarization in nonrhythmic regimes whereas, in δ ([2–4 Hz]) oscillatory regimes, the graded levels of rhythmicity in the LFP mapped into a stereotypical oscillatory pattern of membrane potential. Finally, we showed that the variability of network states, beyond the occurrence of slow oscillatory activity, critically shaped the average correlations between single-cell and population signals. Application of the LFP-based NSI to mouse visual cortex data showed that this index increased with pupil size and during locomotion and had a U-shaped dependence on population firing rates. NSI-based characterization provides a ready-to-use tool to understand from LFP recordings how the modulation of local network dynamics shapes the flexibility of sensory processing during behavior.

Study of the synergistic effect of singlet oxygen with other plasma-generated ROS in fungi inactivation during water disinfection

Cold atmospheric plasma (CAP) possesses the ability of high-efficiency disinfection. It is reported that mixtures of reactive oxygen species (ROS) including ·OH, 1O2, O2− and H2O2 generated from CAP have better antimicrobial ability than mimicked solution of mixture of single ROS type, but the reason is not clear. In this study, CAP was applied to treat yeasts in water in order to investigate the fungal inactivation efficiency and mechanism. The results showed that plasma treatment for 5 min could result in >2-log reduction of yeast cells, and application of varied ROS scavengers could significantly increase the yeast survival rate, indicating that ·OH and 1O2 played the pivotal role in yeast inactivation. Moreover, the synergistic effect of 1O2 with other plasma-generated ROS was revealed. 1O2 could diffuse into cells and induce the depolarization of mitochondrial membrane potential (MMP), and different levels of MMP depolarization determined different cell death modes. Mild damage of mitochondria during short-term plasma treatment could lead to apoptosis. For long-term plasma treatment, the cell membrane could be severely damaged by the plasma-generated ·OH, so a large amount of 1O2 could induce more depolarization of MMP, leading to increase of intracellular O2− and Fe2+ which subsequently caused cell inactivation. 1O2 could also induce protein aggregation and increase of RIP1/RIP3 necrosome, leading to necroptosis. With participation of 1O2, endogenous ·OH could also be generated via Fenton and Haber-Weiss reactions during plasma treatment, which potentiated necroptosis. Adding l-His could mitigate membrane damage, inhibit the drop of MMP and the formation of necrosome, and thus prevent the happening of necroptosis. These findings may deepen the understanding of plasma sterilization mechanisms and provide guidance for microbial killing in the environment.

IL-22 Protects against Biliary Ischemia-Reperfusion Injury after Liver Transplantation via Activating STAT3 and Reducing Apoptosis and Oxidative Stress Levels In Vitro and In Vivo.

Biliary complications are currently one of the leading causes of liver failure and patient death after liver transplantation and need to be solved urgently. Biliary ischemia-reperfusion injury (IRI) is one of the important causes of biliary complications. IL-22 has a protective effect on liver injury and hepatitis diseases, and its safety and efficacy in the treatment of hepatitis have also been proved in human clinical experiments. Furthermore, multiple studies have confirmed that IL-22 promotes the proliferation and repair of epithelial cells in various organs. Still, its function in the bile duct after transplantation has not been explored. This study was aimed at investigating the effects of IL-22 on cholangiocyte IRI in vitro and in vivo and exploring its underlying mechanisms. We simulated the hypoxia process of bile duct epithelial cells through in vitro experiments to investigate the protective function and molecular mechanism of IL-22 on bile duct epithelial cells. Subsequently, the function and mechanism of IL-22 in the biliary IRI model of autologous orthotopic liver transplantation in rats were assessed. This study confirmed that IL-22 could promote cholangiocyte proliferation, decrease the apoptosis rate of cholangiocytes and tissues, decrease MDA levels, and increase SOD levels by activating STAT3. In addition, IL-22 can also reduce the level of mitochondrial membrane depolarization, protect mitochondria, reduce ROS production, and play a role in protecting bile ducts. These findings provide evidence for IL-22 as a novel and effective treatment for biliary IRI after liver transplantation.

Effectiveness of Hyperthermia as Monotherapy and Adjuvant Therapy Approaches Against an In Vitro Model of Colorectal Carcinoma.

Despite improvement in current therapies, the 5-year overall survival rate of colorectal carcinoma is still low especially in its metastatic form. On the other hand, hyperthermia has been utilized as a cancer treatment approach to improve overall therapeutic efficacy. In the present study, we have aimed to develop an optimized hyperthermic protocol against an in vitro model of human colon carcinoma, as a single and/or adjuvant treatment approach. We have utilized an in vitro model of human colorectal carcinoma consisting of colorectal carcinoma (HT29, CaCo2) and normal colon epithelial (CCD841CoN) cell lines. Cells were exposed to 45°C, over 120 min, in the presence or absence of chemotherapeutic (5-Fluorouracil, Capecitabine) and targeted (Bevacizumab, Cetuximab) drugs. Cell viability levels were determined by the Alamar-blue assay while determination of cell death, reactive oxygen species (ROS) production, mitochondrial membrane depolarization (ΔΨμ) levels and cell cycle progression were performed by flow cytometry. CaCo2 and HT29 cells showed a differential response towards i) cell viability, ii) cell death, iii) ROS and ΔΨμ levels as well as iv) cell cycle distribution, in the presence of hyperthermia alone (monotherapy) or in combination with the above-mentioned drugs (adjuvant therapy). Finally, normal colon epithelial (CCD841CoN) cells remained minimally affected. We have developed an optimized experimental hyperthermic protocol, as a promising monotherapy and/or adjuvant therapy approach, with the capacity to potentiate chemotherapeutic as well as targeted drug-induced cytotoxicity against a model of colorectal carcinoma, to a variable degree.

Antifungal activity of dexamethasone against fluconazole-resistant Candida albicansand its activity against biofilms.

Objective: The present study investigated the antifungal action of dexamethasone disodium phosphate (Dex). Methodology: Susceptibility testing was performed using the Clinical & Laboratory Standards Institute protocol; M27-A3, checkerboard test and biofilm were evaluated with two isolates of Candida albicans, hyphal production test, molecular docking analysis and flow cytometry analysis. Result: Dex and fluconazole (FLC) together had a synergistic effect. Mature biofilm wasreducedwhen treated with Dex alone or in combination. Dex and FLC promoted a decrease in the production of hyphae and changes in the level of mitochondrial depolarization, increased generation of reactive oxygen species, loss of membrane integrity, increased phosphatidylserine externalization and molecular docking; there was interaction with ALS3 and SAP5 targets. Conclusion: Dex showed antifungal activity against FLC-resistant C. albicans strains.

Protective effects of dietary curcumin and astaxanthin against heat-induced ROS production and skeletal muscle injury in male and female C57BL/6J mice

AimsThis study aimed to: 1) investigate sex differences in heat-induced mitochondrial dysfunction, ROS production, and skeletal muscle injury in mice; 2) evaluate whether curcumin and astaxanthin, alone or together, would prevent those heat-induced changes. Main methodsMale and female C57BL/6J mice were treated with curcumin and astaxanthin for 10 days, then exposed to 39.5 °C heat for up to 3 h. Heat-induced hyperthermia, changes in mitochondrial morphology and function, and oxidative damage to skeletal muscle were evaluated. Key findingsAlthough female mice had a slightly higher basal core body temperature (Tc) than male mice, peak Tc during heat exposure was significantly lower in females than in males. Heat increased ROS levels in skeletal muscle in both sexes; interestingly, the increases in ROS were greater in females than in males. Despite the above-mentioned differences, heat induced similar levels of mitochondrial fragmentation and membrane potential depolarization, caspase 3/7 activation, and injury in male and female skeletal muscle. Individual treatment of curcumin or astaxanthin did not affect basal and peak Tc but prevented heat-induced mitochondrial dysfunction, ROS increases, and apoptosis in a dose-dependent manner. Moreover, a low-dose combination of curcumin and astaxanthin, which individually showed no effect, reduced the heat-induced oxidative damage to skeletal muscle. SignificanceBoth male and female mice can develop mitochondrial dysfunction and oxidative stress in skeletal muscle when exposed to heat stress. High doses of either curcumin or astaxanthin limit heat-induced skeletal muscle injury, but a low-dose combination of these ingredients may increase their efficacy.