Electrophysiological Mechanisms and Validation of Ferritin-Based Magnetogenetics for Remote Control of Neurons.

Magnetogenetics was developed to remotely control genetically targeted neurons. A variant of magnetogenetics uses magnetic fields to activate transient receptor potential vanilloid (TRPV) channels when coupled with ferritin. Stimulation with static or radiofrequency (RF) magnetic fields of neurons expressing these channels induces Ca2+ transients and modulates behavior. However, the validity of ferritin-based magnetogenetics has been questioned due to controversies surrounding the underlying mechanisms and deficits in reproducibility. Here, we validated the magnetogenetic approach FeRIC using electrophysiological and imaging techniques. Previously, interference from RF stimulation rendered patch-clamp recordings inaccessible for magnetogenetics. We solved this limitation for FeRIC, and we studied the bioelectrical properties of neurons expressing TRPV4 (non-selective cation channel) and TMEM16A (chloride permeable channel) coupled to ferritin (FeRIC channels) under RF stimulation. We used cultured neurons obtained from rat hippocampus of either sex. We show that RF decreases the membrane resistance and depolarizes the membrane potential in neurons expressing TRPV4FeRIC RF does not directly trigger action potential firing but increases the neuronal basal spiking frequency. In neurons expressing TMEM16AFeRIC, RF decreases the membrane resistance, hyperpolarizes the membrane potential, and decreases the spiking frequency. Additionally, we corroborated the previously described biochemical mechanism responsible for RF-induced activation of ferritin-coupled ion channels. We solved an enduring problem for ferritin-based magnetogenetics, obtaining direct electrophysiological evidence of RF-induced activation of ferritin-coupled ion channels. We found that RF does not yield instantaneous changes in neuronal membrane potentials. Instead, RF produces responses that are long-lasting and moderate, but effective in controlling the bioelectrical properties of neurons.Significance statement Cell-specific and non-invasive stimulation can be a powerful tool for modulating neuronal circuits and functions. Magnetogenetic techniques that are fully genetically encoded provide such tools. However, there have been significant controversies surrounding the efficacy and underlying mechanisms of magnetogenetics. Here, we demonstrate that by employing a fully genetically encoded magnetogenetic approach called FeRIC, we can modulate neuronal voltage, inducing either depolarization or hyperpolarization through the activation of ion channels with magnetic fields; we validate this modulation mechanism with the gold-standard patch-clamp technique. We further discover that this neuronal modulation is not achieved by instantaneously triggering action potentials as previously assumed, but by modulating neuronal excitability.

Sound production biomechanics in three-spined toadfish and potential functional consequences of swim bladder morphology in the Batrachoididaea).

The relationship between sound complexity and the underlying morphology and physiology of the vocal organ anatomy is a fundamental component in the evolution of acoustic communication, particularly for fishes. Among vertebrates, the mammalian larynx and avian syrinx are the best-studied vocal organs, and their ability to produce complex vocalizations has been modeled. The range and complexity of the sounds in mammalian lineages have been attributed, in part, to the bilateral nature of the vocal anatomy. Similarly, we hypothesize that the bipartite swim bladder of some species of toadfish (family Batrachoididae) is responsible for complex nonlinear characters of the multiple call types that they can produce, supported by nerve transection experiments. Here, we develop a low-dimensional coupled-oscillator model of the mechanics underlying sound production by the two halves of the swim bladder of the three-spined toadfish, Batrachomoeus trispinosus. Our model was able to replicate the nonlinear structure of both courtship and agonistic sounds. The results provide essential support for the hypothesis that fishes and tetrapods have converged in an evolutionary innovation for complex acoustic signaling, namely, a relatively simple bipartite mechanism dependent on sonic muscles contracting around a gas filled structure.

Accurate Microwave Circuit Co-Simulation Method Based on Simplified Equivalent Circuit Modeling.

A new co-simulation method is proposed for active devices and electromagnetic resonant circuits at microwave frequency range. For the measured and extracted device parameters, three steps of equivalent circuit models are processed of the general, simplified, and EM RLC models. To overcome the limited lumped element simulation in an electromagnetic simulator, the simplified equivalent circuit model is established by mathematical computation. The co-simulation procedures are described and experimentally verified for commercial diodes. The application circuit is designed and implemented using the proposed co-simulation method. The experimental results verify that design using the proposed co-simulated method presented excellent agreement for a wideband frequency range of 0-4 GHz, compared with that using a conventional design method. The proposed co-simulation method can be applied to any commercial EM simulation tools without active model error.

Rapid Immunodot AQP4 Assay for Neuromyelitis Optica Spectrum Disorder.

Importance: Immunoglobulin G autoantibodies for aquaporin 4 (AQP4-IgG) serve as diagnostic biomarkers for neuromyelitis optica spectrum disorder (NMOSD), and the most sensitive and specific laboratory tests for their detection are cell-based assays (CBAs). Nevertheless, the limited availability of special instruments limits the widespread use of CBAs in routine laboratories. Objective: To validate an enzyme immunodot assay for simple and rapid detection of AQP4-IgG. Design, Setting, and Participants: This multicenter case-control study, conducted from May 2020 to February 2023, involved 4 medical centers (3 in China and 1 in Korea). The study included patients with AQP4-IgG-positive NMOSD, patients with other immune-related diseases, and healthy control individuals. Participants were excluded if they did not agree to participate or if their serum sample had turbidity. Exposures: Serum AQP4 antibodies measured with immunodot assay. Main Outcomes and Measures: The main outcome was performance of the immunodot assay compared with the gold standard CBA for detecting AQP4-IgG. To examine generalizability, cross-validation in Korea and at a second site in China, validation of patients with other immune-related diseases, and follow-up validation of the original cohort were performed. Results: A total of 836 serum samples were collected; 400 were included in the diagnostic study and 436 in the validation sets. In a head-to-head diagnostic study involving 200 patients with NMOSD with AQP4-IgG (mean [SD] age, 43.1 [13.5] years; 188 [94%] female) and 200 healthy controls, use of an immunodot assay demonstrated antibody detection performance comparable to that of the gold standard (κ = 98.0%). The validation sets included 47 patients with NMOSD and 26 patients with other autoimmune diseases from Korea, 31 patients with NMOSD at a second site in China, 275 patients with other diseases, and 57 patients with NMOSD at follow-up. In the validation study, of 436 cases, 2 (<1%) were false positive and none were false negative. The CBA identified 332 AQP4-IgG-positive samples and 504 negative samples (200 [40%] in controls and 304 [60%] in patients with other diseases); 2 of the positive cases (<1%) were false negative and 4 of the negative cases (<1%) were false positive. The overall sensitivity of the immunodot assay was 99.4% (95% CI, 97.8%-99.9%), and the specificity was 99.2% (95% CI, 98.0%-99.8%). Conclusions and Relevance: This case-control study found that the immunodot assay was comparable to CBA for detecting AQP4-IgG. With its time- and cost-efficient characteristics, the immunodot assay may be a practical option for AQP4-IgG detection.

Antigen-independent IL-17A production by bystander-activated CD4+IL-1R1+ cells in patients with multiple sclerosis.

Multiple sclerosis (MS) is a demyelinating disease caused by auto-antigen recognizing CD4+ T cells. However, IL-17A-producing CD4+ T cells that are bystander-activated by IL-1ß and IL-23, and T cell receptors independently, could contribute to experimental autoimmune encephalomyelitis. Here, we studied the differences in the frequency and function of bystander-activated CD4+ T cells in patients with MS. A significantly higher frequency of CD4 + IL-1Rl + T cells was found in memory than in naïve CD4+ T cells and in Th17/Th17.1 than in Th1/Th2 subtypes in both MS and healthy controls (HC). Following IL-1ß and IL-23 stimulation, IL-1Rl expression was markedly increased in both memory and Th17/Th17.1 cells, and their IL-17A-production was increased after bystander-activation, which was significantly higher in MS compared with HC. Our study suggests a potential role of IL-17A-producing bystander-activated CD4+IL-1Rl+ T cells in MS.

Short- and long-term exposure to air pollution increases the risk of stroke.

OBJECTIVE: Many epidemiological studies have observed the association of air pollutant exposure with the onset, progression, and mortality of stroke. The aim of this study was to investigate the associations of air pollutants, including SO2, NO2, O3, CO, and PM10, with stroke according to exposure duration. METHODS: Data from the Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2015 were obtained. The 21,240 patients who were admitted for or died due to stroke were 1:4 matched for age, sex, income, and region of residence with 84,960 control participants. The meteorological factors of mean, highest, and lowest temperatures; relative humidity; ambient atmospheric pressure; and air pollutant concentrations (SO2, NO2, O3, CO, and PM10) were analyzed to determine their associations with stroke. The odds ratios for stroke after exposure to each meteorological factor and air pollutant at 7 and 30 days were calculated in the stroke and control groups. Subgroup analyses were conducted according to age, sex, income, and region of residence. RESULTS: The odds ratio associated with seven days of exposure to CO was 1.16 (95% CI = 1.04-1.31) in stroke patients. For 30 days of exposure, the odds ratio associated with CO was 1.16 (95% CI = 1.02-1.32) in stroke patients. Seven and 30 days of NO2 exposure were inversely associated with stroke. The odds ratio associated with seven days of exposure to O3 was 1.16 (95% CI = 1.01-1.32) in ischemic stroke patients. Both ischemic and hemorrhagic stroke had negative associations with 7 and 30 days of NO2 exposure. CONCLUSION: Both short- and long-term exposure to CO were related to stroke.

Functional impairment of CD19+CD24hiCD38hi B cells in neuromyelitis optica spectrum disorder is restored by B cell depletion therapy.

The role of B cells in immune response regulation is context dependent. In some cases, bystander B cell activation leads to interleukin-10 (IL-10) production, suppressing inappropriate immune responses. However, the role of B cells in regulation of autoimmune diseases, including neuromyelitis optica spectrum disorder (NMOSD), is incompletely understood. NMOSD is an autoimmune disease of the central nervous system with a relapsing-remitting course in which acute attacks lead to severe disability. B cell depletion therapy (BCDT) has shown clinical efficacy in NMOSD by eliminating pathogenic B cells; however, its effect on regulatory B (Breg) cells remains elusive. Here, we evaluated the B cell subsets, Breg cell function, and the effect of BCDT on these cells in patients with NMOSD. We showed that CD24hiCD38hi B cells from patients with NMOSD did not inhibit CD4+ T cell production of interferon-γ (IFN-γ), IL-17, or IL-21 and failed to inhibit follicular helper T cell expansion or induce regulatory T cells. This cellular impairment in patients with NMOSD can be explained by deficient Breg cell numbers and Breg cell­intrinsic deficits in IL-10 production specifically in response to B cell bystander activation. Using cross-sectional and 3-year longitudinal studies, we showed that BCDT treatment restored the numerical deficiency of Breg cells. Moreover, the post-BCDT repopulated CD24hiCD38hi B cells restored IL-10 production and suppressed IFN-γ and IL-17 production by CD4+ T cells. Our results suggest that both numerical deficiency of CD24hiCD38hi B cells and their impaired regulatory function contribute to NMOSD pathophysiology, and function is restored after BCDT.

Efficacy and Safety of Bioabsorbable Bone Hemostatic Agent in Total Knee Arthroplasty: A Prospective Randomized Controlled Trial.

Although a bioabsorbable bone hemostatic agent (BBHA) was developed approximately 20 years ago to overcome the shortcomings of conventional bone wax, its bleeding control capacity has not yet been studied. This study was aimed at investigating the efficacy and safety of BBHA in total knee arthroplasty (TKA). Sixty-two patients who underwent unilateral primary TKA for knee osteoarthritis were included and randomized to the control or BBHA group. Before releasing the tourniquet, BBHA was applied on the bone-cut surface that was not covered by implants. The primary variable was the drainage volume during the postoperative period. The secondary outcomes were total estimated blood loss (EBL), hemoglobin level, hematocrit level, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, range of motion (ROM), pain visual analog scale (VAS) score, and rate of complications. There were no significant differences in drainage volume or EBL between the 2 groups. Hemoglobin and hematocrit levels were higher in the BBHA group during the 4-week postoperative period; however, the intergroup differences were not significant. The ESR, CRP, ROM, and pain VAS scores in the BBHA group were not significantly different from the corresponding values in the control group. No specific complications were observed. Although BBHA was found to be safe without complications, it did not decrease bleeding after TKA in general cases. Further studies are necessary to evaluate the efficacy of BBHA in patients with coagulation problems.

Short and long term exposure to air pollution increases the risk of ischemic heart disease.

Previous studies have suggested an increased risk of ischemic heart disease related to air pollution. This study aimed to explore both the short-term and long-term effects of air pollutants on the risk of ischemic heart disease after adjusting for meteorological factors. The Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2013 was used. Overall, 2155 participants with ischemic heart disease and 8620 control participants were analyzed. The meteorological data and air pollution data, including SO2 (ppm), NO2 (ppm), O3 (ppm), CO (ppm), and particulate matter (PM)10 (µg/m3), were analyzed using conditional logistic regression. Subgroup analyses were performed according to age, sex, income, and region of residence. One-month exposure to SO2 was related to 1.36-fold higher odds for ischemic heart disease (95% confidence interval [95% CI] 1.06-1.75). One-year exposure to SO2, O3, and PM10 was associated with 1.58- (95% CI 1.01-2.47), 1.53- (95% CI 1.27-1.84), and 1.14 (95% CI 1.02-1.26)-fold higher odds for ischemic heart disease. In subgroup analyses, the ≥ 60-year-old group, men, individuals with low income, and urban groups demonstrated higher odds associated with 1-month exposure to SO2. Short-term exposure to SO2 and long-term exposure to SO2, O3, and PM10 were related to ischemic heart disease.

Short- and long-term exposure to air pollution and lack of sunlight are associated with an increased risk of depression: A nested case-control study using meteorological data and national sample cohort data.

Previous studies have suggested an increased risk of depression related to air pollutants. This study investigated the relationship of air pollutant exposure and meteorological factors with depression. The Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2013 was analyzed. In total, 25,589 depression participants were 1:4 matched with 102,356 control participants for age, sex, income, and region of residence. Depression was defined based on a diagnosis (ICD-10: F31-33) by a psychiatric physician. Meteorological factors and air pollutants including sulfur dioxide (SO2) (ppm), nitrogen dioxide (NO2) (ppm), ozone (O3) (ppm), carbon monoxide (CO) (ppm), and particulate matter with an aerodynamic diameter <10 µm (PM10) (µg/m3) during the 30 days and 365 days before the index date were analyzed for associations with depression using conditional logistic regression. Subgroup analyses were performed according to age, sex, income, and region of residence. The odds ratios (ORs) for depression were 1.05 (95% CI = 1.02-1.08) at 365 days for 1 h less of sunshine. The ORs for depression were 1.02 (95% CI = 1.01-1.03) and 1.03 (95% CI = 1.00-1.05) at 30 days and 365 days for PM10 (10 µg/m3), respectively. The ORs for depression were 1.18 (95% CI = 1.04-1.35) and 1.25 (95% CI = 1.07-1.47) at 30 days and 365 days for CO (ppm), respectively. In the subgroup analyses, the overall results were consistent. However, statistical significance diminished in the younger, high-income, and urban resident subgroups. Both short- and long-term exposure to PM10 and CO and a reduced duration of sunshine were related to an increased risk of depression.

Production and Its Anti-hyperglycemic Effects of γ-Aminobutyric Acid from the Wild Yeast Strain Pichia silvicola UL6-1 and Sporobolomyces carnicolor 402-JB-1.

This study was done to produce γ-aminobutyric acid (GABA) from wild yeast as well as investigate its anti-hyperglycemic effects. Among ten GABA-producing yeast strains, Pichia silvicola UL6-1 and Sporobolomyces carnicolor 402-JB-1 produced high GABA concentration of 134.4 µg/mL and 179.2 µg/mL, respectively. P. silvicola UL6-1 showed a maximum GABA yield of 136.5 µg/mL and 200.8 µg/mL from S. carnicolor 402-JB-1 when they were cultured for 30 hr at 30℃ in yeast extract-peptone-dextrose medium. The cell-free extract from P. silvicola UL6-1 and S. carnicolor 402-JB-1 showed very high anti-hyperglycemic α-glucosidase inhibitory activity of 72.3% and 69.9%, respectively. Additionally, their cell-free extract-containing GABA showed the anti-hyperglycemic effect in streptozotocin-induced diabetic Sprague-Dawley rats.

Isolation and Identification of Yeasts from Wild Flowers Collected around Jangseong Lake in Jeollanam-do, Republic of Korea, and Characterization of the Unrecorded Yeast Bullera coprosmaensis.

Several types of yeasts were isolated from wild flowers around Jangseong Lake in Jeollanam-do, Republic of Korea and identified by comparing the nucleotide sequences of the PCR amplicons for the D1/D2 variable domain of the 26S ribosomal DNA using Basic Local Alignment Search Tool (BLAST) analysis. In total, 60 strains from 18 species were isolated, and Pseudozyma spp. (27 strains), which included Pseudozyma rugulosa (7 strains) and Pseudozyma aphidis (6 strains), was dominant species. Among the 60 strains, Bullera coprosmaensis JS00600 represented a newly recorded yeast strain in Korea, and its microbiological characteristics were investigated. The yeast cell has an oval-shaped morphology measuring 1.4 × 1.7 µm in size. Bullera coprosmaensis JS00600 is an asporous yeast that exhibits no pseudomycelium formation. It grew well in vitamin-free medium as well as in yeast extract-malt extract broth and yeast extract-peptone-dextrose (YPD) broth, and it is halotolerant growing in 10% NaCl-containing YPD broth.