Colonic Dysmotility in Murine Partial Colonic Obstruction Due to Functional Changes in Interstitial Cells

Qianqian Wang,Jingyu Zang,Xu Huang,Hongli Lu,Wenxie Xu,Jie Chen 대한소화기 기능성질환∙운동학회 2019 Journal of Neurogastroenterology and Motility (JNM Vol.25 No.4

Background/Aims Interstitial cells play important roles in gastrointestinal (GI) neuro-smooth muscle transmission. The underlying mechanisms of colonic dysmotility have not been well illustrated. We established a partial colon obstruction (PCO) mouse model to investigate the changes of interstitial cells and the correlation with colonic motility. Methods Western blot technique was employed to observe the protein expressions of Kit, platelet-derived growth factor receptor-α (Pdgfra), Ca2+-activated Cl− (Ano1) channels, and small conductance Ca2+- activated K+ (SK) channels. Colonic migrating motor complexes (CMMCs) and isometric force measurements were employed in control mice and PCO mice. Results PCO mice showed distended abdomen and feces excretion was significantly reduced. Anatomically, the colon above the obstructive silicone ring was obviously dilated. Kit and Ano1 proteins in the colonic smooth muscle layer of the PCO colons were significantly decreased, while the expression of Pdgfra and SK3 proteins were significantly increased. The effects of a nitric oxide synthase inhibitor (L-NAME) and an Ano1 channel inhibitor (NPPB) on CMMC and colonic spontaneous contractions were decreased in the proximal and distal colons of PCO mice. The SK agonist, CyPPA and antagonist, apamin in PCO mice showed more effect to the CMMCs and colonic smooth muscle contractions. Conclusions Colonic transit disorder may be due to the downregulation of the Kit and Ano1 channels and the upregulation of SK3 channels in platelet-derived growth factor receptor-α positive (PDGFRα+) cells. The imbalance between interstitial cells of Cajal-Ano1 and PDGFRα-SK3 distribution might be a potential reason for the colonic dysmotility. Background/Aims Interstitial cells play important roles in gastrointestinal (GI) neuro-smooth muscle transmission. The underlying mechanisms of colonic dysmotility have not been well illustrated. We established a partial colon obstruction (PCO) mouse model to investigate the changes of interstitial cells and the correlation with colonic motility. Methods Western blot technique was employed to observe the protein expressions of Kit, platelet-derived growth factor receptor-α (Pdgfra), Ca2+-activated Cl− (Ano1) channels, and small conductance Ca2+- activated K+ (SK) channels. Colonic migrating motor complexes (CMMCs) and isometric force measurements were employed in control mice and PCO mice. Results PCO mice showed distended abdomen and feces excretion was significantly reduced. Anatomically, the colon above the obstructive silicone ring was obviously dilated. Kit and Ano1 proteins in the colonic smooth muscle layer of the PCO colons were significantly decreased, while the expression of Pdgfra and SK3 proteins were significantly increased. The effects of a nitric oxide synthase inhibitor (L-NAME) and an Ano1 channel inhibitor (NPPB) on CMMC and colonic spontaneous contractions were decreased in the proximal and distal colons of PCO mice. The SK agonist, CyPPA and antagonist, apamin in PCO mice showed more effect to the CMMCs and colonic smooth muscle contractions. Conclusions Colonic transit disorder may be due to the downregulation of the Kit and Ano1 channels and the upregulation of SK3 channels in platelet-derived growth factor receptor-α positive (PDGFRα+) cells. The imbalance between interstitial cells of Cajal-Ano1 and PDGFRα-SK3 distribution might be a potential reason for the colonic dysmotility.

Calcium-activated chloride channels: a new target to control the spiking pattern of neurons

( Go Eun Ha ),( Eunji Cheong ) 생화학분자생물학회(구 한국생화학분자생물학회) 2017 BMB Reports Vol.50 No.3

The nature of encoded information in neural circuits is determined by neuronal firing patterns and frequencies. This paper discusses the molecular identity and cellular mecha-nisms of spike-frequency adaptation in the central nervous system (CNS). Spike-frequency adaptation in thalamocortical (TC) and CA1 hippocampal neurons is mediated by the Ca²⁺-activated Cl^- channel (CACC) anoctamin-2 (ANO2). Knockdown of ANO2 in these neurons results in increased number of spikes, in conjunction with significantly reduced spike-frequency adaptation. No study has so far demonstrated that CACCs mediate afterhyperpolarization currents, which result in the modulation of neuronal spike patterns in the CNS. Our study therefore proposes a novel role for ANO2 in spike-frequency adaptation and transmission of information in the brain. [BMB Reports 2017; 50(3): 109-110]

Gender-specific Association of the ANO1 Genetic Variations with Hypertension

Hyun-Seok Jin,Dongju Jung 대한의생명과학회 2015 Biomedical Science Letters Vol.21 No.3

Development of hypertension is caused by complex contributions of genetic and environmental factors. In spite of the increased understanding of hypertension, genetic factors that contribute to hypertension largely remain elusive. ANO1 gene encoding a calcium-activated chloride channel has recently been reported to affect spontaneous hypertension in the animal model. In this report, we investigated possible association of the ANO1 gene with hypertension in human with ANO1 variants found in Korean population. Fourteen polymorphisms of ANO1 gene were analyzed to be associated with hypertension. Interestingly, the six polymorphisms that showed statistically significant association were all the male subjects. The highest significant SNP was rs7127129 (OR=1.14, CI: 1.02~1.28, additive P=0.023; OR=1.24, CI: 1.03~1.49, dominant P=0.025), and other five SNPs (rs2509153, rs11235473, rs10751200, rs10898827 and rs10899928) were also statistically associated with hypertension. Consequently, we found that the genetic variants of ANO1 present statistically significant associations with hypertension in human, especially, in male. To the best of our knowledge, this study is the first report describing association of genetic polymorphisms of ANO1 with hypertension in human.

Characterization of zinc-dependent metalloprotease motif on rat brain calcium-activated chloride channel accessory 1 (rbCLCA1) processing and localization

RaMi LEE,SangMin JEONG 한국생물공학회 2015 한국생물공학회 학술대회 Vol.2015 No.4

Intracellular Loop in the Brain Isoforms of Anoctamin 2 Channels Regulates Calcium-dependent Activation

이동수,Lim Hocheol,Lee Jungryun,하고은,No Kyoung Tai,정은지 한국뇌신경과학회 2023 Experimental Neurobiology Vol.32 No.3

Anoctamin 2 (ANO2 or TMEM16B), a calcium-activated chloride channel (CaCC), performs diverse roles in neurons throughout the central nervous system. In hippocampal neurons, ANO2 narrows action potential width and reduces postsynaptic depolarization with high sensitivity to Ca2+ at relatively fast kinetics. In other brain regions, including the thalamus, ANO2 mediates activity-dependent spike frequency adaptations with low sensitivity to Ca2+ at relatively slow kinetics. How this same channel can respond to a wide range of Ca2+ levels remains unclear. We hypothesized that splice variants of ANO2 may contribute to its distinct Ca2+ sensitivity, and thus its diverse neuronal functions. We identified two ANO2 isoforms expressed in mouse brains and examined their electrophysiological properties: isoform 1 (encoded by splice variants with exons 1a, 2, 4, and 14) was expressed in the hippocampus, while isoform 2 (encoded by splice variants with exons 1a, 2, and 4) was broadly expressed throughout the brain, including in the cortex and thalamus, and had a slower calcium-dependent activation current than isoform 1. Computational modeling revealed that the secondary structure of the first intracellular loop of isoform 1 forms an entrance cavity to the calcium-binding site from the cytosol that is relatively larger than that in isoform 2. This difference provides structural evidence that isoform 2 is involved in accommodating spike frequency, while isoform 1 is involved in shaping the duration of an action potential and decreasing postsynaptic depolarization. Our study highlights the roles and molecular mechanisms of specific ANO2 splice variants in modulating neuronal functions.

<i>Flos Magnoliae</i> Inhibits Chloride Secretion via ANO1 Inhibition in Calu-3 Cells

Kim, Hyun Jong,Nam, Yu Ran,Nam, Joo Hyun Institute for Advanced Research in Asian Science a 2018 The American journal of Chinese medicine Vol.46 No.5

<P><I>Flos Magnoliae</I> (FM, Chinese name: Xin-yi) is an oriental medicinal herb commonly used for symptomatic relief from allergic rhinitis, sinusitis, and headache, including in traditional Chinese and Korean medicine formulations. FM inhibits histamine release from mast cells and cytokine secretion from T cells. However, the mechanism of action of FM on the anoctamin-1 (ANO1) ion channel, which is responsible for nasal hypersecretion in allergic rhinitis, has not been elucidated. Therefore, in this study, we investigated the effect of a 30% ethanolic extract of FM (FM<SUB>EtOH</SUB>) and its chemical constituents on ANO1 activity. We used high-performance liquid chromatography analysis to identify five major chemical constituents of FM<SUB>EtOH</SUB>: vanillic acid, tiliroside, eudesmin, magnolin, and fargesin. Using a conventional whole-cell patch clamp method, we found that FM<SUB>EtOH</SUB> (30, 100, and 300<TEX>$ \,$</TEX><TEX>$ \mu $</TEX>g/mL) and its chemical constituent tiliroside inhibited ANO1 activity in ANO1-overexpressing HEK293T cells. In addition, we found that the treatment of the airway epithelial cell line Calu-3 with interleukin 4 significantly increased Ca<TEX>$ ^{2+}$</TEX> activated Cl<TEX>$ ^{-}$</TEX> current (I<SUB>CaCC</SUB>), but not cystic fibrosis transmembrane conductance regulator (CFTR)-mediated chloride current (I<SUB>CFTR</SUB>). FM<SUB>EtOH</SUB> and tiliroside specifically inhibited I<SUB>CaCC</SUB>. Thus, in this study, we identified a novel mechanism underlying the alleviation of allergic rhinitis by FM<SUB>EtOH</SUB>. Our results indicate that FM<SUB>EtOH</SUB> and its chemical constituent tiliroside are promising and potent agents for the prevention and treatment of allergic rhinitis.</P>

Spike Frequency Adaptation in Neurons of the Central Nervous System

Ha, Go Eun,Cheong, Eunji The Korean Society for Brain and Neural Science 2017 Experimental Neurobiology Vol.26 No.4

<P>Neuronal firing patterns and frequencies determine the nature of encoded information of the neurons. Here we discuss the molecular identity and cellular mechanisms of spike-frequency adaptation in central nervous system (CNS) neurons. Calcium-activated potassium (K<SUB>Ca</SUB>) channels such as BK<SUB>Ca</SUB> and SK<SUB>Ca</SUB> channels have long been known to be important mediators of spike adaptation via generation of a large afterhyperpolarization when neurons are hyper-activated. However, it has been shown that a strong hyperpolarization via these K<SUB>Ca</SUB> channels would cease action potential generation rather than reducing the frequency of spike generation. In some types of neurons, the strong hyperpolarization is followed by oscillatory activity in these neurons. Recently, spike-frequency adaptation in thalamocortical (TC) and CA1 hippocampal neurons is shown to be mediated by the Ca<SUP>2+</SUP>-activated Cl- channel (CACC), anoctamin-2 (ANO2). Knockdown of ANO2 in these neurons results in significantly reduced spike-frequency adaptation accompanied by increased number of spikes without shifting the firing mode, which suggests that ANO2 mediates a genuine form of spike adaptation, finely tuning the frequency of spikes in these neurons. Based on the finding of a broad expression of this new class of CACC in the brain, it can be proposed that the ANO2-mediated spike-frequency adaptation may be a general mechanism to control information transmission in the CNS neurons.</P>

Calcium Signaling in Salivary Secretion

Jin Man Kim,Sang-Woo Lee,Kyungpyo Park 대한치의학회 2017 Journal of korean dental science Vol.10 No.2

Calcium Signaling in Salivary Secretion

Kim, Jin Man,Lee, Sang-Woo,Park, Kyungpyo Korean Academy of Dental Science 2017 Journal of korean dental science Vol.10 No.2

Calcium has versatile roles in diverse physiological functions. Among these functions, intracellular $Ca^{2+}$ 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 $Ca^{2+}$ 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, $Ca^{2+}$ activates $K^+$ and $Cl^-$ channels to transport water and electrolyte constituting whole saliva. We also focus on the $Ca^{2+}$ signals from intracellular stores with discussion about detailed molecular mechanism underlying the generation of characteristic $Ca^{2+}$ patterns. In particular, inositol triphosphate signal is a main trigger for inducing $Ca^{2+}$ signals required for the salivary gland functions. The biphasic response of inositol triphosphate receptor and $Ca^{2+}$ pumps generate a self-limiting pattern of $Ca^{2+}$ efflux, resulting in $Ca^{2+}$ oscillations. The regenerative $Ca^{2+}$ 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 $Ca^{2+}$ signals in regulating salivary secretion.

Calcium Signaling in Salivary Secretion

김진만,이상우,박경표 대한치의학회 2017 Journal of korean dental science Vol.10 No.2

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.