The Inhibition Effect and Mechanism of Staurosporine Isolated from Streptomyces sp. SNC087 Strain on Nasal Polyp.

This study aims to explore the potential inhibition effects of staurosporine isolated from a Streptomyces sp. SNC087 strain obtained from seawater on nasal polyps. Staurosporine possesses antimicrobial and antihypertensive activities. This research focuses on investigating the effects of staurosporine on suppressing the growth and development of nasal polyps and elucidating the underlying mechanisms involved. The experimental design includes in vitro and ex vivo evaluations to assess the inhibition activity and therapeutic potential of staurosporine against nasal polyps. Nasal polyp-derived fibroblasts (NPDFs) were stimulated with TGF-ß1 in the presence of staurosporine. The levels of α-smooth muscle actin (α-SMA), collagen type-I (Col-1), fibronectin, and phosphorylated (p)-Smad 2 were investigated using Western blotting. VEGF expression levels were analyzed in nasal polyp organ cultures treated with staurosporine. TGF-ß1 stimulated the production of Col-1, fibronectin, and α-SMA and was attenuated by staurosporine pretreatment. Furthermore, these inhibitory effects were mediated by modulation of the signaling pathway of Smad 2 in TGF-ß1-induced NPDFs. Staurosporine also inhibits the production of VEGF in ex vivo NP tissues. The findings from this study will contribute to a better understanding of staurosporine's role in nasal polyp management and provide insights into its mechanisms of action.

Lurasidone blocks the voltage-gated potassium channels of coronary arterial smooth muscle cells.

Lurasidone is a second-generation antipsychotic drug used to treat schizophrenia, mania, and bipolar disorder. The drug is an antagonist of the 5-HT2A and D2 receptors. No effect of lurasidone on the voltage-gated K+ (Kv) channels has yet been identified. Here, we show that lurasidone inhibits the vascular Kv channels of rabbit coronary arterial smooth muscle cells in a dose-dependent manner with an IC50 of 1.88 ± 0.21 µM and a Hill coefficient of 0.98 ± 0.09. Although lurasidone (3 µM) did not affect the activation kinetics, the drug negatively shifted the inactivation curve, suggesting that the drug interacted with the voltage sensors of Kv channels. Application of 1 or 2 Hz train steps in the presence of lurasidone significantly increased Kv current inhibition. The recovery time after channel inactivation increased in the presence of lurasidone. These results suggest that the inhibitory action of lurasidone is use (state)-dependent. Pretreatment with a Kv 1.5 subtype inhibitor effectively reduced the inhibitory effect of lurasidone. However, the inhibitory effect on Kv channels did not markedly change after pretreatment with a Kv 2.1 or a Kv7 subtype inhibitor. In summary, lurasidone inhibits vascular Kv channels (primarily the Kv1.5 subtype) in a concentration- and use (state)-dependent manner by shifting the steady-state inactivation curve.

Inhibition of voltage-dependent K+ currents of rabbit coronary arterial smooth muscle cells by the atypical antipsychotic paliperidone.

Paliperidone, an atypical antipsychotic, is widely used to treat schizophrenia. In this study, we explored whether paliperidone inhibited the voltage-dependent K+ (Kv) channels of rabbit coronary arterial smooth muscle cells. Paliperidone reduced Kv channel activity in a concentration-dependent manner with a half-maximal inhibitory concentration (IC50 ) of 16.58 ± 3.03 µM and a Hill coefficient of 0.60 ± 0.04. It did not significantly shift the steady-state activation or inactivation curves, suggesting that the drug did not affect the gating properties of Kv channels. In the presence of paliperidone, the application of 20 repetitive depolarizing pulses at 1 and 2 Hz gradually increased the inhibition of the Kv current. Further, the recovery time constant after Kv channel inactivation was increased by paliperidone, indicating that it inhibited the Kv channel in a use (state)-dependent manner. Its inhibitory effects were reduced by pretreatment with a Kv1.5 subtype inhibitor. However, pretreatment with a Kv2.1 or Kv7 inhibitor did not reduce its inhibitory effect. We conclude that paliperidone inhibits Kv channels (mainly Kv1.5 subtype channels) in a concentration- and use (state)-dependent manner without changing channel gating.

Antidiabetic omarigliptin dilates rabbit aorta by activating voltage-dependent K+ channels and the sarco/endoplasmic reticulum Ca2+ -ATPase pump.

We investigated the vasodilatory effect of omarigliptin, an oral antidiabetic drug in the dipeptidyl peptidase-4 inhibitor class, and its related mechanisms using phenylephrine (Phe)-induced pre-contracted aortic rings. Omarigliptin dilated aortic rings pre-constricted with Phe in a dose-dependent manner. Pretreatment with the voltage-dependent K+ channel inhibitor 4-aminopyridine significantly attenuated the vasodilatory effect of omarigliptin, whereas pretreatment with the inwardly rectifying K+ channel inhibitor Ba2+ , ATP-sensitive K+ channel inhibitor glibenclamide, and large-conductance Ca2+ -activated K+ channel inhibitor paxilline did not alter its vasodilation. Pretreatment with the sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA) pump inhibitors thapsigargin and cyclopiazonic acid significantly reduced the vasodilatory effect of omarigliptin. Neither cAMP/PKA-related signaling pathway inhibitors nor cGMP/PKG-related signaling pathway inhibitors modulated the vasodilatory effect of omarigliptin. Removal of endothelium did not diminish the vasodilatory effect of omarigliptin. Furthermore, pretreatment with the nitric oxide synthase inhibitor L-NAME or small-conductance Ca2+ -activated K+ channel inhibitor apamin, together with the intermediate-conductance Ca2+ -activated K+ channel inhibitor TRAM-34, did not influence the vasodilatory effect of omarigliptin. In conclusion, omarigliptin induced vasodilation in rabbit aortic smooth muscle by activating voltage-dependent K+ channels and the SERCA pump independently of other K+ channels, cAMP/PKA- and cGMP/PKG-related signaling pathways, and the endothelium.

Antifibrosis Efficacy of Apo-9-Fucoxanthinone-Contained Sargassum horneri Ethanol Extract on Nasal Polyp: An In Vitro and Ex Vivo Organ Culture Assay.

Sargassum horneri is a seaweed species with diverse bioactivities. However, its antifibrotic effects during nasal polyp (NP) formation are not clearly understood. Therefore, we investigated the inhibitory effect of S. horneri on fibrosis progression in NP-derived fibroblasts (NPDFs) and NP tissues ex vivo. NPDFs were stimulated with TGF-ß1 in the presence or absence of S. horneri ethanol extract (SHE). The extracellular matrix (ECM) protein production levels, myofibroblast differentiation (α-smooth muscle actin, α-SMA), and phosphorylation of Smad 2/3 and -ERK in TGF-ß1-stimulated NPDFs were investigated using western blotting. Further, the contractile activity of SHE was assessed by performing a collagen gel contraction assay. The expression levels of collagen-1, fibronectin, and α-SMA were investigated in NP organ cultures treated with SHE. TGF-ß1 stimulated ECM protein expression, myofibroblast differentiation, and collagen contractile activity while these were attenuated by pretreatment with SHE. We also found antifibrotic effect of SHE on ex vivo NP tissues. The antifibrotic effects of SHE were modulated through the attenuation of Smad 2/3 and ERK signaling pathways in TGF-ß1-stimulated NPDFs. In conclusion, SHE inhibited ECM protein accumulation and myofibroblast differentiation during NP remodeling. Thus, SHE may be helpful as a treatment for NP recurrence after endoscopic sinus surgery.

Marine Biological Macromolecules and Chemically Modified Macromolecules; Potential Anticoagulants.

Coagulation is a potential defense mechanism that involves activating a series of zymogens to convert soluble fibrinogen to insoluble fibrin clots to prevent bleeding and hemorrhagic complications. To prevent the extra formation and diffusion of clots, the counterbalance inhibitory mechanism is activated at levels of the coagulation pathway. Contrariwise, this system can evade normal control due to either inherited or acquired defects or aging which leads to unusual clots formation. The abnormal formations and deposition of excess fibrin trigger serious arterial and cardiovascular diseases. Although heparin and heparin-based anticoagulants are a widely prescribed class of anticoagulants, the clinical use of heparin has limitations due to the unpredictable anticoagulation, risk of bleeding, and other complications. Hence, significant interest has been established over the years to investigate alternative therapeutic anticoagulants from natural sources, especially from marine sources with good safety and potency due to their unique chemical structure and biological activity. This review summarizes the coagulation cascade and potential macromolecular anticoagulants derived from marine flora and fauna.

Asenapine, an atypical antipsychotic, blocks voltage-gated potassium channels in rabbit coronary artery smooth muscle cells.

We investigated the effect of asenapine, a commonly used atypical antipsychotic, on voltage-dependent K+ (Kv) channels in rabbit coronary artery smooth muscle cells. Asenapine inhibited the Kv current in a concentration-dependent manner, with an half-inhibitory concentration (IC50) value of 8.59 ± 2.25 µM and Hill coefficient of 0.64 ± 0.06. Although asenapine did not affect the steady-state activation curve of Kv channels, it shifted the voltage dependence of the steady-state inactivation curve toward a more negative potential. Asenapine increased the recovery time constant of channel inactivation and produced use (state)-dependent inhibition of Kv channels at a stimulation frequency of 1 or 2 Hz. Pretreatment with the Kv1.5 subtype inhibitor DPO-1 reduced the Kv current; however, additional application of asenapine did not further inhibit the Kv current. Pretreatment with the Kv2.1 subtype inhibitor guangxitoxin and Kv7 inhibitor linopirdine also reduced the Kv current. However, additional application of asenapine further reduced the Kv current, similar to the application of asenapine alone. Asenapine induced membrane depolarization and vasoconstriction. Based on these results, we conclude that asenapine inhibits the Kv current in concentration- and use (state)-dependent manners by shifting the inactivation curve. The major target of asenapine is the Kv1.5 subtype channel.

Inhibitory effects of the atypical antipsychotic, clozapine, on voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells.

To investigate the adverse effects of clozapine on cardiovascular ion channels, we examined the inhibitory effect of clozapine on voltage-dependent K+ (Kv) channels in rabbit coronary arterial smooth muscle cells. Clozapine-induced inhibition of Kv channels occurred in a concentration-dependent manner with an half-inhibitory concentration value of 7.84 ± 4.86 µM and a Hill coefficient of 0.47 ± 0.06. Clozapine did not shift the steady-state activation or inactivation curves, suggesting that it inhibited Kv channels regardless of gating properties. Application of train pulses (1 and 2 Hz) progressively augmented the clozapine-induced inhibition of Kv channels in the presence of the drug. Furthermore, the recovery time constant from inactivation was increased in the presence of clozapine, suggesting that clozapine-induced inhibition of Kv channels is use (state)-dependent. Pretreatment of a Kv1.5 subtype inhibitor decreased the Kv current amplitudes, but additional application of clozapine did not further inhibit the Kv current. Pretreatment with Kv2.1 or Kv7 subtype inhibitors partially blocked the inhibitory effect of clozapine. Based on these results, we conclude that clozapine inhibits arterial Kv channels in a concentrationand use (state)-dependent manner. Kv1.5 is the major subtype involved in clozapine-induced inhibition of Kv channels, and Kv2.1 and Kv7 subtypes are partially involved.

Benzyl Isothiocyanate Attenuates Inflammasome Activation in Pseudomonas aeruginosa LPS-Stimulated THP-1 Cells and Exerts Regulation through the MAPKs/NF-κB Pathway.

Inflammasomes are a group of intracellular multiprotein platforms that play important roles in immune systems. Benzyl isothiocyanate (BITC) is a constituent of cruciferous plants and has been confirmed to exhibit various biological activities. The modulatory effects of BITC on inflammasome-mediated interleukin (IL)-1ß expression and its regulatory mechanisms in Pseudomonas aeruginosa (P. aeruginosa) LPS/ATP-stimulated THP-1 cells was investigated. Monocytic THP-1 cells were treated with phorbol myristate acetate (PMA) to induce differentiation into macrophages. Enzyme-linked immunosorbent assays (ELISA) were performed to measure the levels of IL-1ß produced in P. aeruginosa LPS/ATP-exposed THP-1 cells. Western blotting was performed to examine the BITC modulatory mechanisms in inflammasome-mediated signaling pathways. BITC inhibited IL-1ß production in P. aeruginosa LPS/ATP-induced THP-1 cells. BITC also inhibited activation of leucine-rich repeat protein-3 (NLRP3) and caspase-1 in P. aeruginosa LPS/ATP-induced THP-1 cells. Furthermore, we show that mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) activation in P. aeruginosa LPS was attenuated by BITC. These BITC-mediated modulatory effects on IL-1ß production may have therapeutic potential for inflammasome-mediated disorders such as a nasal polyp.

A phlorotannins-loaded homogeneous acellular matrix film modulates post-implantation inflammatory responses.

Peritendinous adhesion mainly occurs between proliferating fibrous tissues and adjacent normal organs after surgery. Many physical barriers are applied to the implanted site to prevent peritendinous adhesion. However, these barriers often trigger inflammatory responses. Therefore, our study sought to develop phlorotannins-loaded cartilage acellular matrix (CAM) films as a physical barrier and investigate their inhibitory effect on inflammatory responses, which are associated with the induction of postoperative peritendinous adhesion (PAA). Our findings indicated that incorporating phlorotannin into the CAM film did not affect its unique characteristics including its thermal and spectroscopic properties. Moreover, the phlorotannins-loaded CAM films suppressed the expression of inflammatory mediators on RAW 264.7 macrophages stimulated using Escherichia coli lipopolysaccharides and exhibited an anti-inflammatory effect when implanted subcutaneously in rats. Therefore, our results highlight the potential of phlorotannins-loaded CAM films as a promising physical barrier to prevent PAA.

Dieckol induces cell cycle arrest by down-regulating CDK2/cyclin E in response to p21/p53 activation in human tracheal fibroblasts.

The phlorotannin derivative dieckol isolated from Ecklonia cava has been shown to exhibit anti-inflammatory, anti-bacterial, anti-oxidative anti-adipogenic and anti-stenosis activity. However, the role of dieckol in cyclin-dependent kinase 2 (CDK2)/cyclin E signalling, which regulates fibrosis development, has not yet been determined. In this study, we report that dieckol-suppressed cell proliferation through the cell cycle arrest of Hs680.Tr human tracheal fibroblasts. Following consecutive purification, dieckol was identified as a potent bioactive compound. The results showed that dieckol had significant anti-proliferative activity against Hs680.Tr human tracheal fibroblastsWestern blotting analysis also found that dieckol dose-dependently induced the cell cycle arrest of Hs680.Tr fibroblasts in the G0/G1 phase, accompanied by the downregulation of CDK2 and cyclin E and the upregulation of p21 and p53. As attested by molecular docking study, the dieckol interacted with the core interface residues in transforming growth factor-ß receptor with high affinity. These findings suggest that dieckol from E. cava inhibits the cell proliferation of Hs680.Tr, potentially through p21- and p53-mediated G0/G1 cell cycle arrest.

Anti-Allergic Effect of Low Molecular Weight Digest from Abalone Viscera on Atopic Dermatitis-Induced NC/Nga.

Abalone viscera (AV) is one of the byproducts of the seafood processing industry. The low molecular weight (<5 kDa) peptides (LMW-AV) obtained from gastrointestinal digestion of AV could suppress allergenic responses on activated HMC-1 human mast cells in our previous study. Regarding the allergenic response of LMW-AV, in the present study, we further investigated the potential of oral administration of LMW-AV against atopic dermatitis (AD) in a dermatitis-induced model stimulated with Dermatophagoides farinae. The results demonstrated that the LMW-AV reduced a number of clinical symptoms, such as the severity of the dermatitis and serum immunoglobulin E levels. Moreover, LMW-AV could inhibit the expression of chemokines and cytokines. The histological analysis indicated that the LMW-AV has suppressed the eosinophil count and the mast cell infiltration into the upper dermis. The results suggest that LMW-AV can be considered as a promising candidate for AD treatment.

Atypical antipsychotic olanzapine inhibits voltage-dependent K+ channels in coronary arterial smooth muscle cells.

BACKGROUND: Olanzapine, an FDA-approved atypical antipsychotic, is widely used to treat schizophrenia and bipolar disorder. In this study, the inhibitory effect of olanzapine on voltage-dependent K+ (Kv) channels in rabbit coronary arterial smooth muscle cells was investigated. METHODS: Electrophysiological recordings were performed in freshly isolated coronary arterial smooth muscle cells. RESULTS: Olanzapine inhibited the Kv channels in a concentration-dependent manner with an IC50 value of 7.76 ± 1.80 µM and a Hill coefficient of 0.82 ± 0.09. Although olanzapine did not change the steady-state activation curve, it shifted the inactivation curve to a more negative potential, suggesting that it inhibited Kv currents by affecting the voltage sensor of the Kv channel. Application of 1 or 2 Hz train pulses did not affect the olanzapine-induced inhibition of Kv channels, suggesting that its effect on Kv channels occurs in a use (state)-independent manner. Pretreatment with DPO-1 (Kv1.5 subtype inhibitor) reduced the olanzapine-induced inhibition of Kv currents. In addition, pretreatment with guangxitoxin (Kv2.1 subtype inhibitor) and linopirdine (Kv7 subtype inhibitor) partially decreased the degree of Kv current inhibition. Olanzapine induced membrane depolarization. CONCLUSION: From these results, we suggest that olanzapine inhibits the Kv channels in a concentration-dependent, but state-independent, manner by affecting the gating properties of Kv channels. The primary Kv channel target of olanzapine is the Kv1.5 subtype.

The anti-diabetic drug alogliptin induces vasorelaxation via activation of Kv channels and SERCA pumps.

In the present study, we investigated the vasorelaxant effects of alogliptin, an oral antidiabetic drug in the dipeptidyl peptidase-4 (DPP-4) inhibitor class, using phenylephrine (Phe)-induced pre-contracted aortic rings. Alogliptin induced vasorelaxation in a dose-dependent manner. Pre-treatment with the voltage-dependent K+ (Kv) channel inhibitor 4-aminopyridine (4-AP) significantly decreased the vasorelaxant effect of alogliptin, whereas pre-treatment with the inwardly rectifying K+ (Kir) channel inhibitor Ba2+, ATP-sensitive K+ (KATP) channel inhibitor glibenclamide, and large-conductance Ca2+-activated K+ (BKCa) channel inhibitor paxilline did not alter the effects of alogliptin. Although pre-treatment with the Ca2+ channel inhibitor nifedipine did not affect the vasorelaxant effect of alogliptin, pre-treatment with the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump inhibitors thapsigargin and cyclopiazonic acid effectively attenuated the vasorelaxant response of alogliptin. Neither cGMP/protein kinase G (PKG)-related signaling pathway inhibitors (guanylyl cyclase inhibitor ODQ and PKG inhibitor KT 5823) nor cAMP/protein kinase A (PKA)-related signaling pathway inhibitors (adenylyl cyclase inhibitor SQ 22536 and PKA inhibitor KT 5720) reduced the vasorelaxant effect of alogliptin. Similarly, the vasorelaxant effect of alogliptin was not changed by endothelium removal or pre-treatment with the nitric oxide (NO) synthase inhibitor L-NAME or the small- and intermediate-conductance Ca2+-activated K+ (SKCa and IKCa) channel inhibitors apamin and TRAM-34. Based on these results, we suggest that alogliptin induced vasorelaxation in rabbit aortic smooth muscle by activating Kv channels and the SERCA pump independent of other K+ channels, cGMP/PKG-related or cAMP/PKA-related signaling pathways, and the endothelium.

The effects of tegaserod, a gastrokinetic agent, on voltage-gated K+ channels in rabbit coronary arterial smooth muscle cells.

Tegaserod, a gastroprokinetic agent, is used to treat irritable bowel syndrome. Despite its extensive clinical use, little is known about the effects of tegaserod on vascular ion channels, especially K+ channels. Therefore, we examined the effects of tegaserod on voltage-gated K+ (Kv) channels in rabbit coronary arterial smooth muscle cells using the whole-cell patch-clamp technique. Tegaserod inhibited Kv channels in a concentration-dependent manner with an IC50 value of 1.26 ± 0.31 µmol/L and Hill coefficient of 0.81 ± 0.10. Although tegaserod had no effect on the steady-state activation curves of the Kv channels, the steady-state inactivation curve was shifted toward a more negative potential. These results suggest that tegaserod inhibits Kv channels by influencing their voltage sensors. The recovery time constant of channel inactivation was extended in the presence of tegaserod. Furthermore, application of train steps (1 and 2 Hz) in the presence of tegaserod progressively increased the inhibition of Kv currents suggesting that tegaserod-induced Kv channel inhibition is use (state)-dependent. Pretreatment with a Kv1.5 subtype inhibitor suppressed the Kv current. However, additional application of tegaserod did not induce further inhibition. Pretreatment with a Kv2.1 or Kv7 inhibitor did not affect the inhibitory effect of tegaserod on Kv channels. Based on these results, we conclude that tegaserod inhibits vascular Kv channels in a concentration- and use (state)-dependent manner independent of its own functions. Furthermore, the major Kv channel target of tegaserod is the Kv1.5 subtype.

3D PCL/fish collagen composite scaffolds incorporating osteogenic abalone protein hydrolysates for bone regeneration application: in vitro and in vivo studies.

Three-dimensional (3 D) printing is an effective technology that has shown considerable potential for use in tissue regeneration. Of the many materials that have been proposed for this purpose, poly (ε-caprolactone) (PCL) 3 D scaffolds have been received significant attention in the bone tissue engineering field due to its advantageous mechanical properties and biocompatibility. In this study, a novel method was developed for tissue-engineered bone that combines PCL 3 D scaffolds with fish collagen (Col) and the osteogenic abalone intestine gastro-intestinal digests (AIGIDs) from Haliotis discus hannai. And then, mouse mesenchymal stem cells (MSCs) were seeded onto the fabricated scaffolds. After in vitro culturing, the proliferation of the MSCs on the scaffolds, alkaline phosphatase (ALP) activity, and the amount of deposited calcium were investigated. The results indicated that the ALP activity and mineralization in PCL/AIGIDs/Col was higher than that of the other scaffolds. In an in vivo experiment, the two fabricated scaffolds were implanted in a rabbit tibia. PCL/AIGIDs/Col group exhibited strong osteoinduction capability in the rabbit tibia defect model. These stimulated biological responses in vitro and in vivo suggest that the PCL/AIGIDs/Col scaffold are promising material for use in tissue implants and bone regeneration.

Suppression of voltage-gated K+ channels by darifenacin in coronary arterial smooth muscle cells.

Darifenacin, an anticholinergic agent, has been used to treat overactive bladder syndrome. Despite its extensive clinical use, there is little information about the effect of darifenacin on vascular ion channels, specifically K+ channels. This study aimed to investigate the effect of the anti-muscarinic drug darifenacin on voltage-gated K+ (Kv) channels, vascular contractility, and coronary blood flow in rabbit coronary arteries. We used the whole-cell patch-clamp technique to evaluate the effect of darifenacin on Kv channels. Darifenacin inhibited the Kv current in a concentration-dependent manner. Applying 1 µM darifenacin shifted the activation and inactivation curves toward a more positive and negative potential, respectively. Darifenacin slowed the time constants of recovery from inactivation. Furthermore, blockade of the Kv current with darifenacin was increased gradually by applying a train of pulses, indicating that darifenacin inhibited Kv currents in a use- (state)-dependent manner. The darifenacin-mediated inhibition of Kv currents was associated with the Kv1.5 subtype, not the Kv2.1 or Kv7 subtype. Applying another anti-muscarinic drug atropine or ipratropium did not affect the Kv current or change the inhibitory effect of darifenacin. Isometric organ bath experiments using isolated coronary arteries were applied to evaluate whether darifenacin-induced inhibition of the Kv channel causes vasocontraction. Darifenacin substantially induced vasocontraction. Furthermore, darifenacin caused membrane depolarization and decreased coronary blood flow. From these results, we concluded that darifenacin inhibits the Kv currents in concentration- and use- (state)-dependent manners. Inhibition of the Kv current with darifenacin occurred by shifting the steady-state activation and inactivation curves regardless of its anti-muscarinic effect.

Inhibition by Imipramine of the Voltage-Dependent K+ Channel in Rabbit Coronary Arterial Smooth Muscle Cells.

Imipramine, a tricyclic antidepressant, is used in the treatment of depressive disorders. However, the effect of imipramine on vascular ion channels is unclear. Therefore, using a patch-clamp technique we examined the effect of imipramine on voltage-dependent K+ (Kv) channels in freshly isolated rabbit coronary arterial smooth muscle cells. Kv channels were inhibited by imipramine in a concentration-dependent manner, with an IC50 value of 5.55 ± 1.24 µM and a Hill coefficient of 0.73 ± 0.1. Application of imipramine shifted the steady-state activation curve in the positive direction, indicating that imipramine-induced inhibition of Kv channels was mediated by influencing the voltage sensors of the channels. The recovery time constants from Kv-channel inactivation were increased in the presence of imipramine. Furthermore, the application of train pulses (of 1 or 2 Hz) progressively augmented the imipramine-induced inhibition of Kv channels, suggesting that the inhibitory effect of imipramine is use (state) dependent. The magnitude of Kv current inhibition by imipramine was similar during the first, second, and third depolarizing pulses. These results indicate that imipramine-induced inhibition of Kv channels mainly occurs in the closed state. The imipramine-mediated inhibition of Kv channels was associated with the Kv1.5 channel, not the Kv2.1 or Kv7 channel. Inhibition of Kv channels by imipramine caused vasoconstriction. From these results, we conclude that imipramine inhibits vascular Kv channels in a concentration- and use (closed-state)-dependent manner by changing their gating properties regardless of its own function.

Inhibitory Effects of a Sargassum miyabei Yendo on Cutibacterium acnes-Induced Skin Inflammation.

Acne vulgaris is a chronic inflammatory condition of skin sebaceous follicles. To explore its effects on acne vulgaris, we investigated the antibacterial and anti-inflammatory activities of Sargassum miyabei Yendo (a brown alga) ethanolic extract (SMYEE) on Cutibacterium acnes (C. acnes)-stimulated inflammatory responses, both in vivo and in vitro. To induce inflammation in vivo, C. acnes was intradermally injected into the dorsal skin of mice, to which SMYEE was applied. The antimicrobial activity of SMYEE was evaluated by the determination of minimum inhibitory concentrations (MICs). To explore in vitro anti-inflammatory effects, HaCaT cells were stimulated with C. acnes after treatment with SMYEE. The levels of IL-8 and the underlying molecular effects in C. acnes-stimulated HaCaT cells were assessed by enzyme-linked immunosorbent assay, Western blotting, and an electrophoretic mobility shift assay. Mouse skin lesions improved after treatment with SMYEE (50 µg/mouse). Neutrophil infiltration was significantly reduced in SMYEE-treated compared to SMYEE-untreated skin lesions. SMYEE reversed the C. acnes-induced increase in IL-8 levels in HaCaT cells and suppressed dHL-60 cell migration. SMYEE also inhibited C. acnes-induced phosphorylation of the extracellular signal-regulated kinase and inhibited activator protein-1 signaling. SMYEE may be a useful treatment for C. acnes-induced acne vulgaris.

Antithrombin III-mediated blood coagulation inhibitory activity of chitosan sulfate derivatized with different functional groups.

Acylated chitosan sulfate (ChS1), a sulfated polysaccharide with high anticoagulant activity, was chemically synthesized and structurally characterized using FT-IR analysis. The beneficial structural properties and high availability of the sulfate group in ChS1 led to greater anticoagulant activity through both the intrinsic and common pathways with antithrombin III (AT III)-mediated inhibition, particularly involving coagulation factors FXa and FIIa. The analysis of the binding affinities using surface plasma resonance found that the equilibrium dissociation constant (KD) of ChS1 for FXa and FIIa in the presence of AT III was 67.4 nM and 112.6 nM, respectively, indicating the stronger interaction of the AT III/ChS1 complex with the ligands and the inhibition of activated FX and FII. The results of amidolytic assays further demonstrated the stronger inhibition of the proteolytic conversion of factor X by the intrinsic FXase complex and of FII by the prothrombinase complex. Molecular docking analysis further validated the protein-ligand interactions of ChS1 with AT III and their binding affinity.