Requirement of ß subunit for the reduced voltage-gated Na+ current of a Brugada syndrome patient having novel double missense mutation (p.A385T/R504T) of SCN5A.

Mutations within the SCN5A gene, which encodes the α-subunit 5 (NaV1.5) of the voltage-gated Na+ channel, have been linked to three distinct cardiac arrhythmia disorders: long QT syndrome type 3, Brugada syndrome (BrS), and cardiac conduction disorder. In this study, we have identified novel missense mutations (p.A385T/R504T) within SCN5A in a patient exhibiting overlap arrhythmia phenotypes. This study aims to elucidate the functional consequences of SCN5A mutants (p.A385T/R504T) to understand the clinical phenotypes. Whole-cell patch-clamp technique was used to analyze the NaV1.5 current (INa) in HEK293 cells transfected with the wild-type and mutant SCN5A with or without SCN1B co-expression. The amplitude of INa was not altered in mutant SCN5A (p.A385T/R504T) alone. Furthermore, a rightward shift of the voltage-dependent inactivation and faster recovery from inactivation was observed, suggesting a gain-of-function state. Intriguingly, the coexpression of SCN1B with p.A385T/R504T revealed significant reduction of INa and slower recovery from inactivation, consistent with the loss-of-function in Na+ channels. The SCN1B dependent reduction of INa was also observed in a single mutation p.R504T, but p.A385T co-expressed with SCN1B showed no reduction. In contrast, the slower recovery from inactivation with SCN1B was observed in A385T while not in R504T. The expression of SCN1B is indispensable for the electrophysiological phenotype of BrS with the novel double mutations; p.A385T and p.R504T contributed to the slower recovery from inactivation and reduced current density of NaV1.5, respectively.

Regulation of T Lymphocyte Functions through Calcium Signaling Modulation by Nootkatone.

Recent advancements in understanding the intricate molecular mechanisms underlying immunological responses have underscored the critical involvement of ion channels in regulating calcium influx, particularly in inflammation. Nootkatone, a natural sesquiterpenoid found in Alpinia oxyphylla and various citrus species, has gained attention for its diverse pharmacological properties, including anti-inflammatory effects. This study aimed to elucidate the potential of nootkatone in modulating ion channels associated with calcium signaling, particularly CRAC, KV1.3, and KCa3.1 channels, which play pivotal roles in immune cell activation and proliferation. Using electrophysiological techniques, we demonstrated the inhibitory effects of nootkatone on CRAC, KV1.3, and KCa3.1 channels in HEK293T cells overexpressing respective channel proteins. Nootkatone exhibited dose-dependent inhibition of channel currents, with IC50 values determined for each channel. Nootkatone treatment did not significantly affect cell viability, indicating its potential safety for therapeutic applications. Furthermore, we observed that nootkatone treatment attenuated calcium influx through activated CRAC channels and showed anti-proliferative effects, suggesting its role in regulating inflammatory T cell activation. These findings highlight the potential of nootkatone as a natural compound for modulating calcium signaling pathways by targeting related key ion channels and it holds promise as a novel therapeutic agent for inflammatory disorders.

SAK3 confers neuroprotection in the neurodegeneration model of X-linked Dystonia-Parkinsonism.

Background X-linked Dystonia-Parkinsonism(XDP) is an adult-onset neurodegenerative disorder that results in the loss of striatal medium spiny neurons (MSNs). XDP is associated with disease-specific mutations in and around the TAF1 gene. This study highlights the utility of directly reprogrammed MSNs from fibroblasts of affected XDP individuals as a platform that captures cellular and epigenetic phenotypes associated with XDP-related neurodegeneration. In addition, the current study demonstrates the neuroprotective effect of SAK3 currently tested in other neurodegenerative diseases. Methods XDP fibroblasts from three independent patients as well as age- and sex-matched control fibroblasts were used to generate MSNs by direct neuronal reprogramming using miRNA-9/9*-124 and thetranscription factors CTIP2 , DLX1 -P2A- DLX2 , and MYT1L . Neuronal death, DNA damage, and mitochondrial health assays were carried out to assess the neurodegenerative state of directly reprogrammed MSNs from XDP patients (XDP-MSNs). RNA sequencing and ATAC sequencing were performed to infer changes in the transcriptomic and chromatin landscapesof XDP-MSNs compared to those of control MSNs (Ctrl-MSNs). Results Our results show that XDP patient fibroblasts can be successfully reprogrammed into MSNs and XDP-MSNs display several degenerative phenotypes, including neuronal death, DNA damage, and mitochondrial dysfunction, compared to Ctrl-MSNs reprogrammed from age- and sex-matched control individuals' fibroblasts. In addition, XDP-MSNs showed increased vulnerability to TNFα -toxicity compared to Ctrl-MSNs. To dissect the altered cellular state in XDP-MSNs, we conducted transcriptomic and chromatin accessibility analyses using RNA- and ATAC-seq. Our results indicate that pathways related to neuronal function, calcium signaling, and genes related to other neurodegenerative diseases are commonly altered in XDP-MSNs from multiple patients. Interestingly, we found that SAK3, a T-type calcium channel activator, that may have therapeutic values in other neurodegenerative disorders, protected XDP-MSNs from neuronal death. Notably, we found that SAK3-mediated alleviation of neurodegeneration in XDP-MSNs was accompanied by gene expression changes toward Ctrl-MSNs.

Challenges in the Therapeutic Targeting of KCa Channels: From Basic Physiology to Clinical Applications.

Calcium-activated potassium (KCa) channels are ubiquitously expressed throughout the body and are able to regulate membrane potential and intracellular calcium concentrations, thereby playing key roles in cellular physiology and signal transmission. Consequently, it is unsurprising that KCa channels have been implicated in various diseases, making them potential targets for pharmaceutical interventions. Over the past two decades, numerous studies have been conducted to develop KCa channel-targeting drugs, including those for disorders of the central and peripheral nervous, cardiovascular, and urinary systems and for cancer. In this review, we synthesize recent findings regarding the structure and activating mechanisms of KCa channels. We also discuss the role of KCa channel modulators in therapeutic medicine. Finally, we identify the major reasons behind the delay in bringing these modulators to the pharmaceutical market and propose new strategies to promote their application.

Atmospheric environment and persistence of pediatric asthma: A population-based cohort study.

BACKGROUND: Asthma is a heterogeneous disease with different outcomes. For children with asthma at the age of 7 years, 67-75% are symptom-free as adults. Data on the important link between childhood and adult asthma are sparse. OBJECTIVE: We aimed to investigate factors associated with persistence of childhood asthma over three years of follow-up by linking data between Korea childhood Asthma Study (KAS) and their matched claims data from Health Insurance Review and Assessment Service (HIRA). METHODS: We analyzed data from 450 preadolescent children aged 7 to 10 years and classified them into remission or persistence groups. Baseline clinical characteristics and exposure to air pollution materials including PM2.5 and PM10 during three years of follow-up were compared. The main outcome was asthma persistence which was defined as the presence of asthma episodes with healthcare utilization and prescription of asthma medications within three years after KAS enrollment. RESULTS: At the third year of follow-up, after stepwise regression analysis, lower age at enrollment (adjusted odds ratio (aOR): 0.79; 95% confidence interval (CI): 0.64-0.96), male sex (aOR: 1.66; 95%CI: 1.05-2.63), proximity from an air-polluting facility (aOR: 2.4; 95%CI: 1.34-4.29), higher level outdoor PM2.5 (aOR: 1.1; 95%CI: 1.02-1.20), and higher rate of doctor-diagnosed food allergy (FA) (aOR: 2.33; 95%CI: 1.06-5.12) were significantly associated with persistence. CONCLUSION: We discovered various independent risk factors for the persistence of childhood asthma. By linking HIRA claims data, we could clarify risk factors for persistence in a well-defined study population.

Anti-Inflammatory Effects of Alphitolic Acid Isolated from Agrimonia coreana Nakai Extracts Are Mediated via the Inhibition of ICRAC Activity in T Cells.

Agrimonia pilosa Ledeb., an important medicinal herb in traditional East Asian medicine, is primarily used to treat abdominal pain, dysentery, and hemostasis. There are ten other reported species of Agrimonia plants, including Agrimonia coreana Nakai-a naturally growing species in South Korea-and Agrimonia eupatoria Linn. Although recent studies have isolated numerous active constituents and investigated their effects, the medicinal utility of this herb is not yet fully explored. Through patch-clamp recording, a previous study reported that Agrimonia plant extracts inhibit the function of Ca2+ release-activated Ca2+ channels (CRACs). Herein, we aimed to identify and isolate the main compounds in A. coreana responsible for CRAC inhibition while assessing the anti-inflammatory effects mediated by this inhibition. We demonstrated for the first time that alphitolic acid isolated from A. coreana has a dose-dependent inhibitory effect on CRAC activity and, thus, an inhibitory effect on intracellular calcium increase. Furthermore, analysis of human CD4+ T cell proliferation via the carboxyfluorescein diacetate succinimidyl ester method revealed that alphitolic acid inhibited T cell proliferation in a concentration-dependent manner. Our findings provide a theoretical basis for the potential therapeutic use of alphitolic acid in the treatment of inflammatory diseases.

Risk factors for renal involvement in Henoch-Schönlein purpura

Abstract Objective: Henoch-Schönlein purpura is a systemic vasculitis that mainly occurs in children. Renal impairment is a major complication of Henoch-Schönlein purpura, but there is no established predictive marker for renal involvement. Thus, in this study, we investigated the risk factors for renal involvement in children with Henoch-Schönlein purpura. Method: The medical records of children newly diagnosed as having Henoch-Schönlein purpura between 2005 and 2020 were reviewed retrospectively. Selected laboratory data were recorded before treatment initiation. The date and the age at diagnosis; sex; and the presence of arthralgia, gastrointestinal and renal involvement were obtained retrospectively. Results: This study included a total of 186 patients with Henoch-Schönlein purpura. Among them, 36.0% had renal involvement; 28.4% had only microscopic hematuria, 53.7% had nonnephrotic range proteinuria, and 17.9% had nephrotic-range proteinuria during follow-up. The mean age was higher (p = 0.016) and female sex was predominant (p = 0.001) in patients with renal involvement than in those without renal involvement. Blood neutrophil/lymphocyte ratio (p = 0.002) and platelet/lymphocyte ratio (p = 0.002) were significantly higher than that of the patients without renal involvement. No statistically significant differences were observed in the hemoglobin concentration, platelet count, presence of arthralgia, and gastrointestinal involvement between patients with and without renal involvement. Logistic regression analysis revealed female sex (odd ratio = 3.213) and neutrophil/lymphocyte ratio (odd ratio = 1.329) as risk factors for renal involvement. Conclusions: Female sex and high neutrophil/lymphocyte ratio were risk factors for renal involvement in Henoch-Schönlein purpura.