Mechanism of essential oil from Schizonepeta tenuifolia in treatment of depression based on network pharmacology and experimental verification / 中国中药杂志

This paper aimed to explore the antidepressant effect of the essential oil from Schizonepeta tenuifolia Briq.(EOST) on the treatment of depression and its mechanism by using a combination of network pharmacology and the mouse model of lipopolysaccharide(LPS)-induced depression. The chemical components in EOST were identified using gas chromatography-mass spectrometer(GC-MS), and 12 active components were selected as the study objects. The targets related to EOST were obtained by Traditional Chinese Medicines Systems Pharmacology(TCMSP) and SwissTargetPrediction database. The targets related to depression were screened out through GeneCards, Therapeutic Target Database(TTD), and Online Mendelian Inheritance in Man(OMIM) database. The Venny 2.1 was applied to screen out the common targets of EOST and depression. The targets were imported into Cytoscape 3.7.2 to generate "drug-active component-diease-target" network diagram. The protein-protein interaction(PPI) network was constructed using STRING 11.5 database and Cytoscape 3.7.2, and the core targets were screened out. DAVID 6.8 database was used for Gene Ontology(GO) func-tional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis, and subsequently the enrichment results were visualized through the bioinformatics platform. The mouse model of depression was induced by intraperitoneally injecting with LPS in mice. Before modeling, mice were administrated orally with EOST. The antidepressant effect of EOST was evalua-ted by tail suspension test(TST), forced swimming test(FST), and novelty suppressed feeding test(NSFT) after modeling. The content of interleukin(IL)-1β was determined by enzyme-linked immunosorbent assay(ELISA), and the protein expression levels of IL-1β and pro IL-1β in the hippocampus were determined by Western blot. There were 12 main components and 179 targets in EOAT, of which, 116 targets were related to depression, mainly involved in neuroactive ligand-receptor interaction, calcium signaling pathway, and cyclic adenosine monophosphate(cAMP) signaling pathway. Biological processes such as synaptic signal transduction, G-protein coupled receptor signaling pathway, and chemical synaptic transmission were involved. Molecular functions such as neurotransmitter receptor activity, RNA polymerase Ⅱ transcription factor activity, and heme binding were involved. In mice experiments, the results showed that EOST at 100 mg·kg~(-1) and 50 mg·kg~(-1) significantly shortened the immobility time in TST and FST as well as the feeding latency in NSFT compared with the model group, decreased the levels of serum IL-1β and NO, and reduced the protein expression levels of IL-1β and pro IL-1β in the hippocampus. In conclusion, EOST shows a good antidepressant effect in a multi-component, multi-target, and multi-pathway manner. The mechanism may be attributed to the fact that EOST can down-regulate the protein expression levels of IL-1β and pro IL-1β, decrease the release of inflammatory factors, and reduce neuroinflammation response.

Inhibitory Effect of Rosae Multiflorae Fructus Extracts on the Receptor Activator of NF-κB Ligand-Induced Osteoclastogenesis through Modulation of P38- and Ca2⁺-Mediated Nuclear Factor of Activated T-Cells Cytoplasmic 1 Expression

BACKGROUND: Rosae Multiflorae fructus (RMF), known to have anti-inflammatory and antioxidant properties, has been used as a traditional remedy for inflammatory diseases such as arthritis in Eastern Asia. However, its effect on osteoclasts, which play a crucial role in resorptive inflammatory bone diseases, is yet to be elucidated.METHODS: The effect of extract of RMF (RMF-E) on receptor activator of nuclear factor-κB ligand (RANKL)-mediated osteoclastogenesis was examined by tartrate-resistant acid phosphatase (TRAP) staining, real-time polymerase chain reaction and western blot analysis. In addition, RANKL-induced Ca2⁺-oscillation was also investigated.RESULTS: RMF-E remarkably inhibited TRAP+-osteoclast and resorptive pit formation in a dose-dependent manner. In addition, the expression of c-Fos and nuclear factor of activated T-cells cytoplasmic, known as pivotal transcription factors for osteoclast formation in vitro and in vivo, and that of the osteoclast differentiation markers such as Acp5, Oscar, CtsK, Atp6v0d2, Tm7sf4, and Nfatc1 were significantly decreased by RMF-E treatment during osteoclastogenesis. The inhibitory effect of RMF-E on RANKL-induced osteoclastogenesis was caused by the suppression of p38 mitogen-activated protein kinase activation, and RANKL-induced Ca2⁺-oscillation removal via inactivation of Bruton's tyrosine kinase (BTK), and subsequently phospholipase C-γ2.CONCLUSIONS: RMF-E negatively regulates osteoclast differentiation and formation. These findings suggest the possibility of RMF-E as a traditional therapeutic agent against osteoclast-related bone disorders such as osteoporosis, rheumatoid arthritis, and periodontitis.

Osteoclasts in the Inflammatory Arthritis: Implications for Pathologic Osteolysis

The enhanced differentiation and activation of osteoclasts (OCs) in the inflammatory arthritis such as rheumatoid arthritis (RA) and gout causes not only local bone erosion, but also systemic osteoporosis, leading to functional disabilities and morbidity. The induction and amplification of NFATc1, a master regulator of OC differentiation, is mainly regulated by receptor activator of NF-κB (RANK) ligand-RANK and calcium signaling which are amplified in the inflammatory milieu, as well as by inflammatory cytokines such as TNFα, IL-1β and IL-6. Moreover, the predominance of CD4+ T cell subsets, which varies depending on the condition of inflammatory diseases, can determine the fate of OC differentiation. Anti-citrullinated peptide antibodies which are critical in the pathogenesis of RA can bind to the citrullinated vimentin on the surface of OC precursors, and in turn promote OC differentiation and function via IL-8. In addition to adaptive immunity, the activation of innate immune system including the nucleotide oligomerization domain leucine rich repeat with a pyrin domain 3 inflammasome and TLRs can regulate OC maturation. The emerging perspectives about the diverse and close interactions between the immune cells and OCs in inflammatory milieu can have a significant impact on the future direction of drug development.

Next-Generation Tools to Study Autonomic Regulation In Vivo / 神经科学通报·英文版

The recent development of tools to decipher the intricacies of neural networks has improved our understanding of brain function. Optogenetics allows one to assess the direct outcome of activating a genetically-distinct population of neurons. Neurons are tagged with light-sensitive channels followed by photo-activation with an appropriate wavelength of light to functionally activate or silence them, resulting in quantifiable changes in the periphery. Capturing and manipulating activated neuron ensembles, is a recently-designed technique to permanently label activated neurons responsible for a physiological function and manipulate them. On the other hand, neurons can be transfected with genetically-encoded Ca indicators to capture the interplay between them that modulates autonomic end-points or somatic behavior. These techniques work with millisecond temporal precision. In addition, neurons can be manipulated chronically to simulate physiological aberrations by transfecting designer G-protein-coupled receptors exclusively activated by designer drugs. In this review, we elaborate on the fundamental concepts and applications of these techniques in research.

Rictor regulates mitochondrial calcium signaling in mouse embryo stem cell-derived cardiomyocytes / 浙江大学学报·医学版

OBJECTIVE@#To explore the expression, localization and regulatory effect on mitochondrial calcium signaling of Rictor in embryonic stem cell-derived cardiomyocytes (ESC-CMs).@*METHODS@#Classical embryonic stem cell cardiomyogenesis model was used for differentiation of mouse embryonic stem cells into cardiomyocytes. The location of Rictor in ESC-CMs was investigated by immunofluorescence and Western blot. The expression of Rictor in mouse embryonic stem cells was interfered with lentiviral technology, then the superposition of mitochondria and endoplasmic reticulum (ER) in ESC-CMs was detected with immunofluorescence method; the cellular ultrastructure of ESC-CMs was observed by transmission electron microscope; the mitochondrial calcium transients of ESC-CMs was detected by living cell workstation;immunoprecipitation was used to detect the interaction between 1,5,5-trisphosphate receptor (IP3 receptor, IP3R), glucose-regulated protein 75 (Grp75) and voltage-dependent anion channel 1 (VDAC1) in mitochondrial outer membrane; the expression of mitochondrial fusion protein (mitonusin-2, Mfn2) was detected by Western blot.@*RESULTS@#Rictor was mainly localized in the endoplasmic reticulum and mitochondrial-endoplasmic reticulum membrane (MAM) in ESC-CMs. Immunofluorescence results showed that Rictor was highly overlapped with ER and mitochondria in ESC-CMs. After mitochondrial and ER were labeled with Mito-Tracker Red and ER-Tracker Green, it was demonstrated that the mitochondria of the myocardial cells in the Rictor group were scattered, and the superimposition rate of mitochondria and ER was lower than that of the negative control group (<0.01). The MAM structures were decreased in ESC-CMs after knockdown of Rictor. The results of the living cell workstation showed that the amplitude of mitochondrial calcium transients by ATP stimulation in ESC-CMs was decreased after knockdown of Rictor (<0.01). The results of co-immunoprecipitation showed that the interaction between IP3R, Grp75 and VDAC1 in the MAM structure of the cardiomyocytes in the Rictor group was significantly attenuated (<0.01); the results of Western blot showed that the expression of Mfn2 protein was significantly decreased (<0.01).@*CONCLUSIONS@#Using lentiviral technology to interfere Rictor expression in mouse embryonic stem cells, the release of calcium from the endoplasmic reticulum to mitochondria in ESC-CMs decreases, which may be affected by reducing the interaction of IP3R, Grp75, VDAC1 and decreasing the expression of Mfn2, leading to the damage of MAM structure.

Long-term dexamethasone treatment diminishes store-operated Ca entry in salivary acinar cells / 国际口腔科学杂志·英文版

Corticosteroids are used in the treatment of many diseases; however, they also induce various side effects. Dexamethasone is one of the most potent corticosteroids, and it has been reported to induce the side effect of impaired salivary gland function. This study aimed to evaluate the effects of dexamethasone on mouse submandibular gland function to gain insight into the mechanism of dexamethasone-induced salivary hypofunction. The muscarinic agonist carbachol (CCh) induced salivary secretion and was not affected by short-term dexamethasone treatment but was decreased following long-term dexamethasone administration. The expression levels of the membrane proteins Na-K-2Cl cotransporter, transmembrane member 16A, and aquaporin 5 were comparable between the control and long-term dexamethasone treatment groups. The CCh-induced increase in calcium concentration was significantly lower in the presence of extracellular Ca in the long-term dexamethasone treatment group compared to that in the control group. Furthermore, CCh-induced salivation in the absence of extracellular Ca and Ca ionophore A23187-induced salivation was comparable between the control and long-term dexamethasone treatment groups. Moreover, salivation induced by the Ca-ATPase inhibitor thapsigargin was diminished in the long-term dexamethasone treatment group. In summary, these results demonstrate that short-term dexamethasone treatment did not impair salivary gland function, whereas long-term dexamethasone treatment diminished store-operated Ca entry, resulting in hyposalivation in mouse submandibular glands.

Long-term Fiber Photometry for Neuroscience Studies / 神经科学通报·英文版

Fiber photometry is a sensitive and easy way to detect changes in fluorescent signals. The combination of fiber photometry with various fluorescent biomarkers has substantially advanced neuroscience research over the last decade. Despite the wide use of fiber photometry in biomedical fields, the lack of a detailed and comprehensive protocol has limited progress and sometimes complicated the interpretation of data. Here, we describe detailed procedures of fiber photometry for the long-term monitoring of neuronal activity in freely-behaving animals, including surgery, apparatus setup, data collection, and analysis.

Melatonin inhibits nicotinic acetylcholine receptor functions in bovine chromaffin cells

Melatonin is a neurotransmitter that modulates various physiological phenomena including regulation and maintenance of the circadian rhythm. Nicotinic acetylcholine receptors (nAChRs) play an important role in oral functions including orofacial muscle contraction, salivary secretion, and tooth development. However, knowledge regarding physiological crosstalk between melatonin and nAChRs is limited. In the present study, the melatonin-mediated modulation of nAChR functions using bovine adrenal chromaffin cells, a representative model for the study of nAChRs, was investigated. Melatonin inhibited the nicotinic agonist dimethylphenylpiperazinium (DMPP) iodide-induced cytosolic free Ca²⁺ concentration ([Ca²⁺](i)) increase and norepinephrine secretion in a concentration-dependent manner. The inhibitory effect of melatonin on the DMPP-induced [Ca²⁺](i) increase was observed when the melatonin treatment was performed simultaneously with DMPP. The results indicate that melatonin inhibits nAChR functions in both peripheral and central nervous systems.

Xylitol stimulates saliva secretion via muscarinic receptor signaling pathway

Xylitol is well-known to have an anti-caries effect by inhibiting the replication of cariogenic bacteria. In addition, xylitol enhances saliva secretion. However, the precise molecular mechanism of xylitol on saliva secretion is yet to be elucidated. Thus, in this study, we aimed to investigate the stimulatory effect of xylitol on saliva secretion and to further evaluate the involvement of xylitol in muscarinic type 3 receptor (M3R) signaling. For determining these effects, we measured the saliva flow rate following xylitol treatment in healthy individuals and patients with dry mouth. We further tested the effects of xylitol on M3R signaling in human salivary gland (HSG) cells using real-time quantitative reverse-transcriptase polymerase chain reaction, immunoblotting, and immunostaining. Xylitol candy significantly increased the salivary flow rate and intracellular calcium release in HSG cells via the M3R signaling pathway. In addition, the expressions of M3R and aquaporin 5 were induced by xylitol treatment. Lastly, we investigated the distribution of M3R and aquaporin 5 in HSG cells. Xylitol was found to activate M3R, thereby inducing increases in Ca²⁺ concentration. Stimulation of the muscarinic receptor induced by xylitol activated the internalization of M3R and subsequent trafficking of aquaporin 5. Taken together, these findings suggest a molecular mechanism for secretory effects of xylitol on salivary epithelial cells.

Profiling of remote skeletal muscle gene changes resulting from stimulation of atopic dermatitis disease in NC/Nga mouse model

Although atopic dermatitis (AD) is known to be a representative skin disorder, it also affects the systemic immune response. In a recent study, myoblasts were shown to be involved in the immune regulation, but the roles of muscle cells in AD are poorly understood. We aimed to identify the relationship between mitochondria and atopy by genome-wide analysis of skeletal muscles in mice. We induced AD-like symptoms using house dust mite (HDM) extract in NC/Nga mice. The transcriptional profiles of the untreated group and HDM-induced AD-like group were analyzed and compared using microarray, differentially expressed gene and functional pathway analyses, and protein interaction network construction. Our microarray analysis demonstrated that immune response-, calcium handling-, and mitochondrial metabolism-related genes were differentially expressed. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology pathway analyses, immune response pathways involved in cytokine interaction, nuclear factor-kappa B, and T-cell receptor signaling, calcium handling pathways, and mitochondria metabolism pathways involved in the citrate cycle were significantly upregulated. In protein interaction network analysis, chemokine family-, muscle contraction process-, and immune response-related genes were identified as hub genes with many interactions. In addition, mitochondrial pathways involved in calcium signaling, cardiac muscle contraction, tricarboxylic acid cycle, oxidation-reduction process, and calcium-mediated signaling were significantly stimulated in KEGG and Gene Ontology analyses. Our results provide a comprehensive understanding of the genome-wide transcriptional changes of HDM-induced AD-like symptoms and the indicated genes that could be used as AD clinical biomarkers.

The role of calmodulin in regulating calcium-permeable PKD2L1 channel activity

Polycystic kidney disease 2-like-1 (PKD2L1), polycystin-L or transient receptor potential polycystin 3 (TRPP3) is a TRP superfamily member. It is a calcium-permeable non-selective cation channel that regulates intracellular calcium concentration and thereby calcium signaling. Although the calmodulin (CaM) inhibitor, calmidazolium, is an activator of the PKD2L1 channel, the activating mechanism remains unclear. The purpose of this study is to clarify whether CaM takes part in the regulation of the PKD2L1 channel, and if so, how. With patch clamp techniques, we observed the current amplitudes of PKD2L1 significantly reduced when coexpressed with CaM and CaMΔN. This result suggests that the N-lobe of CaM carries a more crucial role in regulating PKD2L1 and guides us into our next question on the different functions of two lobes of CaM. We also identified the predicted CaM binding site, and generated deletion and truncation mutants. The mutants showed significant reduction in currents losing PKD2L1 current-voltage curve, suggesting that the C-terminal region from 590 to 600 is crucial for maintaining the functionality of the PKD2L1 channel. With PKD2L1608Stop mutant showing increased current amplitudes, we further examined the functional importance of EF-hand domain. Along with co-expression of CaM, ΔEF-hand mutant also showed significant changes in current amplitudes and potentiation time. Our findings suggest that there is a constitutive inhibition of EF-hand and binding of CaM C-lobe on the channel in low calcium concentration. At higher calcium concentration, calcium ions occupy the N-lobe as well as the EF-hand domain, allowing the two to compete to bind to the channel.

Physical Exercise and Regulation of Intracellular Calcium in Cardiomyocytes of Hypertensive Rats / Exercício Físico e Regulação de Cálcio Intracelular em Cardiomiócitos de Ratos Hipertensos

Abstract Background: Regulation of intracellular calcium (Ca2+) in cardiomyocytes is altered by hypertension; and aerobic exercise brings benefits to hypertensive individuals. Objective: To verify the effects of aerobic exercise training on contractility and intracellular calcium (Ca2+) transients of cardiomyocytes and on the expression of microRNA 214 (miR-214) in the left ventricle of spontaneously hypertensive rats (SHR). Methods: SHR and normotensive Wistar rats of 16 weeks were divided into 4 groups -sedentary hypertensive (SH); trained hypertensive (TH); sedentary normotensive (SN); and trained normotensive (TN). Animals of the TH and TN groups were subjected to treadmill running program, 5 days/week, 1 hour/day at 60-70% of maximum running velocity for 8 weeks. We adopted a p ≤ 0.05 as significance level for all comparisons. Results: Exercise training reduced systolic arterial pressure in hypertensive rats. In normotensive rats, exercise training reduced the time to 50% cell relaxation and the time to peak contraction and increased the time to 50% decay of the intracellular Ca2+ transients. In SHR, exercise increased the amplitude and reduced the time to 50% decay of Ca2+ transients. Exercise training increased the expression of miR-214 in hypertensive rats only. Conclusion: The aerobic training applied in this study increased the availability of intracellular Ca2+ and accelerated the sequestration of these ions in left ventricular myocytes of hypertensive rats, despite increased expression of miR-214 and maintenance of cell contractility.

Resumo Fundamento: A regulação intracelular de cálcio (Ca2+) em cardiomiócitos é alterada pela hipertensão, e o exercício físico aeróbico traz benefícios para hipertensos. Objetivo: Verificar os efeitos do treinamento físico aeróbico sobre a contratilidade e a concentração intracelular de Ca2+ transitória em miócitos e a expressão do microRNA 214 no ventrículo esquerdo (VE) de ratos espontaneamente hipertensos (SHR). Métodos: SHR e ratos Wistar normotensos com 16 semanas de idade foram divididos em 4 grupos de 13 animais cada: hipertenso sedentário (HS); hipertenso treinado (HT); normotenso sedentário (NS); normotenso treinado (NT). Os animais dos grupos HT e NT foram submetidos a um programa de treinamento progressivo de corrida em esteira, 5 dias/semana, 1 hora/dia, em intensidade de 60-70% da velocidade máxima de corrida, durante 8 semanas. Adotou-se p ≤ 0,05 como nível de significância em todas as comparações. Resultados: O treinamento físico reduziu a pressão arterial sistólica nos animais hipertensos. Nos animais normotensos, o treinamento físico reduziu o tempo para 50% de relaxamento celular e o tempo para o pico de contração celular, mas aumentou o tempo para 50% de decaimento da concentração intracelular de Ca2+ transitória. Nos animais SHR, o treinamento físico aumentou a amplitude e reduziu o tempo para 50% de decaimento da concentração intracelular de Ca2+ transitória, sem alterar a contratilidade celular. O treinamento físico aumentou a expressão do miR-214 apenas nos animais hipertensos. Conclusão: O treinamento aeróbico utilizado aumenta a disponibilidade e acelera o sequestro de Ca2+ intracelular em miócitos do VE de ratos hipertensos, apesar do aumento da expressão de miR-214 e da manutenção da contratilidade celular.

Effects of tetramethylypyrazine nitrone on proliferation and differentiation of neural stem cells / 中国应用生理学杂志

OBJECTIVES@#To investigate the role of tetramethylpyrazine(TMP) nitrone in proliferation and differentiation of neural stem cells (NSCs).@*METHODS@#We separated and cultivated the original generation of NSCs from cerebral cortex of 14 days rat embryo, and the phenotype characteristics of the third-generation NSCs was tested by immunofluorescence. The experiment was divided into control group, β-mercaptoethanol positive control group, tetramethylpyrazine nitrone group and tetramethylpyrazine nitrone + ethylene glycol tetraacetic acid(EGTA) group (=4). The third-generation cultivation of NSCs was used in the experiment. The effect of tetramethylpyrazine nitrone on the number of NSCs proliferation was determined by BrdU and MTT, and the differentiation of NSCs was determined by Western blot.@*RESULTS@#The primary NSCs was isolated successfully, neurospheres with typical NSCs morphology and expressing nestin was formed at 3-5 days. As BrdU and MTT assay results shown, compared with the control group andβ-mercaptoethanol positive control group, the NSCs proliferation numbers of tetramethylpyrazine nitrone group increased significantly(<0.05). The results of Western blot showed that the neuronal differentiation rate of NSCs was increased significantly in both the tetramethylpyrazine nitrone group and tetramethylpyrazine nitrone + EGTA group, and the differentiation rate of NSCs in tetramethylpyrazine nitrone + EGTA group increased more significantly(<0.05).@*CONCLUSIONS@#Tetramethylpyrazine nitrone can significantly enhance the proliferation and neuronal differentiation rate of NSCs. Decrease in extracellular Ca can promote the differentiation of NSCs into neurons induced by tetramethylpyrazine nitrone. Ca signaling plays an important role in the differentiation of NSCs into neurons.

Investigation of Pain Mechanisms by Calcium Imaging Approaches / 神经科学通报·英文版

Due to the complex circuitry and plethora of cell types involved in somatosensation, it is becoming increasingly important to be able to observe cellular activity at the population level. In addition, since cells rely on an intricate variety of extracellular factors, it is important to strive to maintain the physiological environment. Many electrophysiological techniques require the implementation of artificially-produced physiological environments and it can be difficult to assess the activity of many cells simultaneously. Moreover, imaging Ca transients using Ca-sensitive dyes often requires in vitro preparations or in vivo injections, which can lead to variable expression levels. With the development of more sensitive genetically-encoded Ca indicators (GECIs) it is now possible to observe changes in Ca transients in large populations of cells at the same time. Recently, groups have used a GECI called GCaMP to address fundamental questions in somatosensation. Researchers can now induce GCaMP expression in the mouse genome using viral or gene knock-in approaches and observe the activity of populations of cells in the pain pathway such as dorsal root ganglia (DRG), spinal neurons, or glia. This approach can be used in vivo and thus maintains the organism's biological integrity. The implementation of GCaMP imaging has led to many advances in our understanding of somatosensation. Here, we review the current findings in pain research using GCaMP imaging as well as discussing potential methodological considerations.

Increased store-operated Ca²⁺ entry mediated by GNB5 and STIM1

Recent human genetic studies have shown that Gβ5 is related to various clinical symptoms, such as sinus bradycardia, cognitive disability, and attention deficit hyperactivity disorder. Although the calcium signaling cascade is closely associated with a heterotrimeric G-protein, the function of Gβ5 in calcium signaling and its relevance to clinical symptoms remain unknown. In this study, we investigated the in vitro changes of store-operated calcium entry (SOCE) with exogenous expression of Gβ5. The cells expressing Gβ5 had enhanced SOCE after depletion of calcium ion inside the endoplasmic reticulum. Gβ5 also augmented Stim1- and Orai1-dependent SOCE. An ORAI1 loss-of-function mutant did not show inhibition of Gβ5-induced SOCE, and a STIM1-ERM truncation mutant showed no enhancement of SOCE. These results suggested a novel role of GNB5 and Stim1, and provided insight into the regulatory mechanism of SOCE.

Calcium Signaling in Salivary Secretion

Calcium has versatile roles in diverse physiological functions. Among these functions, intracellular Ca²⁺ plays a key role during the secretion of salivary glands. In this review, we introduce the diverse cellular components involved in the saliva secretion and related dynamic intracellular Ca²⁺ signals. Calcium acts as a critical second messenger for channel activation, protein translocation, and volume regulation, which are essential events for achieving the salivary secretion. In the secretory process, Ca²⁺ activates K⁺ and Cl⁻ channels to transport water and electrolyte constituting whole saliva. We also focus on the Ca²⁺ signals from intracellular stores with discussion about detailed molecular mechanism underlying the generation of characteristic Ca²⁺ patterns. In particular, inositol triphosphate signal is a main trigger for inducing Ca²⁺ signals required for the salivary gland functions. The biphasic response of inositol triphosphate receptor and Ca²⁺ pumps generate a self-limiting pattern of Ca²⁺ efflux, resulting in Ca²⁺ oscillations. The regenerative Ca²⁺ oscillations have been detected in salivary gland cells, but the exact mechanism and function of the signals need to be elucidated. In future, we expect that further investigations will be performed toward better understanding of the spatiotemporal role of Ca²⁺ signals in regulating salivary secretion.

Force-dependent calcium signaling and its pathway of human neutrophils on P-selectin in flow

P-selectin engagement of P-selectin glycoprotein ligand-1 (PSGL-1) causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector (Fluo-4 AM), the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demonstrated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellular calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neutrophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase (Syk). These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectin-induced calcium signaling of neutrophils in flow.

Activation of transient receptor potential vanilloid 3 by the methanolic extract of Schisandra chinensis fruit and its chemical constituent γ-schisandrin

Transient receptor potential vanilloid 3 (TRPV3) is a non-selective cation channel with modest permeability to calcium ions. It is involved in intracellular calcium signaling and is therefore important in processes such as thermal sensation, skin barrier formation, and wound healing. TRPV3 was initially proposed as a warm temperature sensor. It is activated by synthetic small-molecule chemicals and plant-derived natural compounds such as camphor and eugenol. Schisandra chinensis (Turcz.) Baill (SC) has diverse pharmacological properties including antiallergic, anti-inflammatory, and wound healing activities. It is extensively used as an oriental herbal medicine for the treatment of various diseases. In this study, we investigated whether SC fruit extracts and seed oil, as well as four compounds isolated from the fruit can activate the TRPV3 channel. By performing whole-cell patch clamp recording in HEK293T cells overexpressing TRPV3, we found that the methanolic extract of SC fruit has an agonistic effect on the TRPV3 channel. Furthermore, electrophysiological analysis revealed that γ-schisandrin, one of the isolated compounds, activated TRPV3 at a concentration of 30 µM. In addition, γ-schisandrin (~100 µM) increased cytoplasmic Ca²⁺ concentrations by approximately 20% in response to TRPV3 activation. This is the first report to indicate that SC extract and γ-schisandrin can modulate the TRPV3 channel. This report also suggests a mechanism by which γ-schisandrin acts as a therapeutic agent against TRPV3-related diseases.

Dust particles-induced intracellular Ca²⁺ signaling and reactive oxygen species in lung fibroblast cell line MRC5

Epidemiologic interest in particulate matter (PM) is growing particularly because of its impact of respiratory health. It has been elucidated that PM evoked inflammatory signal in pulmonary epithelia. However, it has not been established Ca²⁺ signaling mechanisms involved in acute PM-derived signaling in pulmonary fibroblasts. In the present study, we explored dust particles PM modulated intracellular Ca²⁺ signaling and sought to provide a therapeutic strategy by antagonizing PM-induced intracellular Ca²⁺ signaling in human lung fibroblasts MRC5 cells. We demonstrated that PM10, less than 10 µm, induced intracellular Ca²⁺ signaling, which was mediated by extracellular Ca²⁺. The PM10-mediated intracellular Ca²⁺ signaling was attenuated by antioxidants, phospholipase blockers, polyADPR polymerase 1 inhibitor, and transient receptor potential melastatin 2 (TRPM2) inhibitors. In addition, PM-mediated increases in reactive oxygen species were attenuated by TRPM2 blockers, clotrimazole (CLZ) and N-(p-amylcinnamoyl) anthranilic acid (ACA). Our results showed that PM10 enhanced reactive oxygen species signal by measuring DCF fluorescence and the DCF signal attenuated by both TRPM2 blockers CLZ and ACA. Here, we suggest functional inhibition of TRPM2 channels as a potential therapeutic strategy for modulation of dust particle-mediated signaling and oxidative stress accompanying lung diseases.

Calcium Signaling of Lysophosphatidylethanolamine through LPA1 in Human SH-SY5Y Neuroblastoma Cells

Lysophosphatidylethanolamine (LPE), a lyso-type metabolite of phosphatidylethanolamine, has been reported to be an intercellular signaling molecule. LPE mobilizes intracellular Ca²⁺ through G-protein-coupled receptor (GPCR) in some cells types. However, GPCRs for lysophosphatidic acid (LPA) were not implicated in the LPE-mediated activities in LPA GPCR overexpression systems or in SK-OV3 ovarian cancer cells. In the present study, in human SH-SY5Y neuroblastoma cells, experiments with LPA₁ antagonists showed LPE induced intracellular Ca²⁺ increases in an LPA₁ GPCR-dependent manner. Furthermore, LPE increased intracellular Ca²⁺ through pertussis-sensitive G proteins, edelfosine-sensitive-phospholipase C, 2-APB-sensitive IP₃ receptors, Ca²⁺ release from intracellular Ca²⁺ stores, and subsequent Ca²⁺ influx across plasma membranes, and LPA acted on LPA₁ and LPA₂ receptors to induce Ca²⁺ response in a 2-APB-sensitive and insensitive manner. These findings suggest novel involvements for LPE and LPA in calcium signaling in human SH-SY5Y neuroblastoma cells.