Channels (Austin, Tex.)最新文献

{"title":"Evaluation of four <i>KCNMA1</i> channelopathy variants on BK channel current under Ca_V1.2 activation.","authors":"Ria L Dinsdale, Andrea L Meredith","doi":"10.1080/19336950.2024.2396346","DOIUrl":"10.1080/19336950.2024.2396346","url":null,"abstract":"<p><p>Variants in <i>KCNMA1</i>, encoding the voltage- and calcium-activated K⁺ (BK) channel, are associated with human neurological disease. The effects of gain-of-function (GOF) and loss-of-function (LOF) variants have been predominantly studied on BK channel currents evoked under steady-state voltage and Ca²⁺ conditions. However, in their physiological context, BK channels exist in partnership with voltage-gated Ca²⁺ channels and respond to dynamic changes in intracellular Ca²⁺ (Ca²⁺_i). In this study, an L-type voltage-gated Ca²⁺ channel present in the brain, Ca_V1.2, was co-expressed with wild type and mutant BK channels containing GOF (D434G, N999S) and LOF (H444Q, D965V) patient-associated variants in HEK-293T cells. Whole-cell BK currents were recorded under Ca_V1.2 activation using buffering conditions that restrict Ca²⁺_i to nano- or micro-domains. Both conditions permitted wild type BK current activation in response to Ca_V1.2 Ca²⁺ influx, but differences in behavior between wild type and mutant BK channels were reduced compared to prior studies in clamped Ca²⁺_i. Only the N999S mutation produced an increase in BK current in both micro- and nano-domains using square voltage commands and was also detectable in BK current evoked by a neuronal action potential within a microdomain. These data corroborate the GOF effect of N999S on BK channel activity under dynamic voltage and Ca²⁺ stimuli, consistent with its pathogenicity in neurological disease. However, the patient-associated mutations D434G, H444Q, and D965V did not exhibit significant effects on BK current under Ca_V1.2-mediated Ca²⁺ influx, in contrast with prior steady-state protocols. These results demonstrate a differential potential for <i>KCNMA1</i> variant pathogenicity compared under diverse voltage and Ca²⁺ conditions.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2396346"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11370921/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142115579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel benzoylurea derivative decreases TRPM7 channel function and inhibits cancer cells migration.","authors":"Xiaoding Zhang, Rui Zong, Yu Han, Xiaoming Li, Shuangyu Liu, Yixue Cao, Nan Jiang, Pingping Chen, Haixia Gao","doi":"10.1080/19336950.2024.2396339","DOIUrl":"10.1080/19336950.2024.2396339","url":null,"abstract":"<p><p>The transient receptor potential melastatin 7 channel (TRPM7) is a nonselective cation channel highly expressed in some human cancer tissues. TRPM7 is involved in the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of cancer cells. Modulation of TRPM7 could be a promising therapeutic strategy for treating cancer; however, efficient and selective pharmacological TRPM7 modulators are lacking. In this study we investigated N- [4- (4, 6-dimethyl- 2-pyrimidinyloxy) - 3- methylphenyl] -N' - [2 -(dimethylamino)] benzoylurea (SUD), a newly synthesized benzoylurea derivative, for its effects on cancer cell migration and EMT and on functional expression of TRPM7. Our previous studies showed that SUD induces cell cycle arrest and apoptosis of MCF-7 and BGC-823 cells (human breast cancer and gastric cancer cell lines, respectively). Here, we show that SUD significantly decreased the migration of both types of cancer cells. Moreover, SUD decreased vimentin expression and increased E-cadherin expression in both cell types, indicating that EMT is also decreased by SUD. Importantly, SUD potentially reduced the TRPM7-like current in a concentration-dependent manner and decreased TRPM7 expression through the PI3K/Akt signaling pathway. Finally, molecular docking simulations were used to investigate potential SUD binding sites on TRPM7. In summary, our research demonstrated that SUD is an effective TRPM7 inhibitor and a potential agent to suppress the metastasis of breast and gastric cancer by inhibiting TRPM7 expression and function.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2396339"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11370923/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142115580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel insights into voltage-gated ion channels: Translational breakthroughs in medical oncology.","authors":"Minas Sakellakis, Sung Mi Yoon, Jashan Reet, Athanasios Chalkias","doi":"10.1080/19336950.2023.2297605","DOIUrl":"10.1080/19336950.2023.2297605","url":null,"abstract":"<p><p>Preclinical evidence suggests that voltage gradients can act as a kind of top-down master regulator during embryogenesis and orchestrate downstream molecular-genetic pathways during organ regeneration or repair. Moreover, electrical stimulation shifts response to injury toward regeneration instead of healing or scarring. Cancer and embryogenesis not only share common phenotypical features but also commonly upregulated molecular pathways. Voltage-gated ion channel activity is directly or indirectly linked to the pathogenesis of cancer hallmarks, while experimental and clinical studies suggest that their modulation, e.g., by anesthetic agents, may exert antitumor effects. A large recent clinical trial served as a proof-of-principle for the benefit of preoperative use of topical sodium channel blockade as a potential anticancer strategy against early human breast cancers. Regardless of whether ion channel aberrations are primary or secondary cancer drivers, understanding the functional consequences of these events may guide us toward the development of novel therapeutic approaches.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2297605"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10761148/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139059243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cell size induced bias of current density in hypertrophic cardiomyocytes.","authors":"Elena Lilliu, Benjamin Hackl, Eva Zabrodska, Stefanie Gewessler, Tobias Karge, Jessica Marksteiner, Jakob Sauer, Eva M Putz, Hannes Todt, Karlheinz Hilber, Xaver Koenig","doi":"10.1080/19336950.2024.2361416","DOIUrl":"10.1080/19336950.2024.2361416","url":null,"abstract":"<p><p>Alterations in ion channel expression and function known as \"electrical remodeling\" contribute to the development of hypertrophy and to the emergence of arrhythmias and sudden cardiac death. However, comparing current density values - an electrophysiological parameter commonly utilized to assess ion channel function - between normal and hypertrophied cells may be flawed when current amplitude does not scale with cell size. Even more, common routines to study equally sized cells or to discard measurements when large currents do not allow proper voltage-clamp control may introduce a selection bias and thereby confound direct comparison. To test a possible dependence of current density on cell size and shape, we employed whole-cell patch-clamp recording of voltage-gated sodium and calcium currents in Langendorff-isolated ventricular cardiomyocytes and Purkinje myocytes, as well as in cardiomyocytes derived from trans-aortic constriction operated mice. Here, we describe a distinct inverse relationship between voltage-gated sodium and calcium current densities and cell capacitance both in normal and hypertrophied cells. This inverse relationship was well fit by an exponential function and may be due to physiological adaptations that do not scale proportionally with cell size or may be explained by a selection bias. Our study emphasizes the need to consider cell size bias when comparing current densities in cardiomyocytes of different sizes, particularly in hypertrophic cells. Conventional comparisons based solely on mean current density may be inadequate for groups with unequal cell size or non-proportional current amplitude and cell size scaling.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2361416"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11155701/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141249093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of the Ca_V1.2 distal carboxy terminus in the regulation of L-type current.","authors":"Felipe Arancibia, Daniela De Giorgis, Franco Medina, Tamara Hermosilla, Felipe Simon, Diego Varela","doi":"10.1080/19336950.2024.2338782","DOIUrl":"https://doi.org/10.1080/19336950.2024.2338782","url":null,"abstract":"<p><p>L-type calcium channels are essential for the excitation-contraction coupling in cardiac muscle. The Ca_V1.2 channel is the most predominant isoform in the ventricle which consists of a multi-subunit membrane complex that includes the Ca_V1.2 pore-forming subunit and auxiliary subunits like Ca_Vα₂δ and Ca_Vβ_2b. The Ca_V1.2 channel's C-terminus undergoes proteolytic cleavage, and the distal C-terminal domain (DC_termD) associates with the channel core through two domains known as proximal and distal C-terminal regulatory domain (PCRD and DCRD, respectively). The interaction between the DC_termD and the remaining C-terminus reduces the channel activity and modifies voltage- and calcium-dependent inactivation mechanisms, leading to an autoinhibitory effect. In this study, we investigate how the interaction between DCRD and PCRD affects the inactivation processes and Ca_V1.2 activity. We expressed a 14-amino acid peptide miming the DCRD-PCRD interaction sequence in both heterologous systems and cardiomyocytes. Our results show that overexpression of this small peptide can displace the DC_termD and replicate the effects of the entire DC_termD on voltage-dependent inactivation and channel inhibition. However, the effect on calcium-dependent inactivation requires the full DC_termD and is prevented by overexpression of calmodulin. In conclusion, our results suggest that the interaction between DCRD and PCRD is sufficient to bring about the current inhibition and alter the voltage-dependent inactivation, possibly in an allosteric manner. Additionally, our data suggest that the DC_termD competitively modifies the calcium-dependent mechanism. The identified peptide sequence provides a valuable tool for further dissecting the molecular mechanisms that regulate L-type calcium channels' basal activity in cardiomyocytes.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2338782"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11067984/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140873666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cardiac L-type calcium channel regulation by Leucine-Rich Repeat-Containing Protein 10.","authors":"Natthaphat Siri-Angkul, Timothy J Kamp","doi":"10.1080/19336950.2024.2355121","DOIUrl":"10.1080/19336950.2024.2355121","url":null,"abstract":"<p><p>L-type calcium channels (LTCCs), the major portal for Ca²⁺ entry into cardiomyocytes, are essential for excitation-contraction coupling and thus play a central role in regulating overall cardiac function. LTCC function is finely tuned by multiple signaling pathways and accessory proteins. Leucine-rich repeat-containing protein 10 (LRRC10) is a little studied cardiomyocyte-specific protein recently identified as a modulator of LTCCs. LRRC10 exerts a remarkable effect on LTCC function, more than doubling L-type Ca²⁺ current (I_Ca,L) amplitude in a heterologous expression system by altering the gating of the channels without changing their surface membrane expression. Genetic ablation of LRRC10 expression in mouse and zebrafish hearts leads to a significant reduction in I_Ca,L density and a slowly progressive dilated cardiomyopathy in mice. Rare sequence variants of LRRC10 have been identified in dilated cardiomyopathy and sudden unexplained nocturnal cardiac death syndrome, but these variants have not been clearly linked to disease. Nevertheless, the DCM-associated variant, I195T, converted LRRC10 from a I_Ca,L potentiator to a I_Ca,L suppressor, thus illustrating the wide dynamic range of LRRC10-mediated I_Ca,L regulation. This review focuses on the contemporary knowledge of LTCC modulation by LRRC10 and discusses potential directions for future investigations.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2355121"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11110685/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141066100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The activation thresholds and inactivation kinetics of poking-evoked PIEZO1 and PIEZO2 currents are sensitive to subtle variations in mechanical stimulation parameters.","authors":"Nadja Zeitzschel, Stefan G Lechner","doi":"10.1080/19336950.2024.2355123","DOIUrl":"10.1080/19336950.2024.2355123","url":null,"abstract":"<p><p>PIEZO1 and PIEZO2 are mechanically activated ion channels that confer mechanosensitivity to various cell types. PIEZO channels are commonly examined using the so-called poking technique, where currents are recorded in the whole-cell configuration of the patch-clamp technique, while the cell surface is mechanically stimulated with a small fire-polished patch pipette. Currently, there is no gold standard for mechanical stimulation, and therefore, stimulation protocols differ significantly between laboratories with regard to stimulation velocity, angle, and size of the stimulation probe. Here, we systematically examined the impact of variations in these three stimulation parameters on the outcomes of patch-clamp recordings of PIEZO1 and PIEZO2. We show that the inactivation kinetics of PIEZO1 and, to a lesser extent, of PIEZO2 change with the angle at which the probe that is used for mechanical stimulation is positioned and, even more prominently, with the size of its tip. Moreover, we found that the mechanical activation threshold of PIEZO2, but not PIEZO1, decreased with increasing stimulation speeds. Thus, our data show that two key outcome parameters of PIEZO-related patch-clamp studies are significantly affected by common variations in the mechanical stimulation protocols, which calls for caution when comparing data from different laboratories and highlights the need to establish a gold standard for mechanical stimulation to improve comparability and reproducibility of data obtained with the poking technique.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2355123"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11734767/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140961341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reducing agents facilitate membrane patch seal integrity and longevity.","authors":"Damayantee Das, Anson Wong, Timothy N Friedman, Bradley J Kerr, Harley T Kurata, Shawn M Lamothe","doi":"10.1080/19336950.2023.2297621","DOIUrl":"10.1080/19336950.2023.2297621","url":null,"abstract":"<p><p>The patch clamp method is a widely applied electrophysiological technique used to understand ion channel activity and cellular excitation. The formation of a high resistance giga-ohm seal is required to obtain high-quality recordings but can be challenging due to variables including operator experience and cell preparation. Therefore, the identification of methods to promote the formation and longevity of giga-ohm seals may be beneficial. In this report, we describe our observation that the application of reducing agents (DTT and TCEP) to the external bath solution during whole-cell patch clamp recordings of heterologous cells (HEK and LM) and cultured primary cells (DRG neurons) enhanced the success of giga-ohm seal formation. Reducing agents also maintained the integrity of the seal for longer periods of time at strong hyperpolarizing voltages, whereas an oxidizing agent (H₂O₂) appeared to have the opposite effect. In summary, we report a useful tool to improve the quality of patch clamp recordings that may be helpful in certain experimental contexts.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2297621"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10761044/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139059244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Binding kinetics of quaternary ammonium ions in Kcv potassium channels.","authors":"Tobias Korn, Ulf-Peter Hansen, Tobias Sebastian Gabriel, Oliver Rauh, Nils Drexler, Indra Schroeder","doi":"10.1080/19336950.2024.2402749","DOIUrl":"10.1080/19336950.2024.2402749","url":null,"abstract":"<p><p>Kcv channels from plant viruses represent the autonomous pore module of potassium channels, devoid of any regulatory domains. These small proteins show very reproducible single-channel behavior in planar lipid bilayers. Thus, they are an optimum system for the study of the biophysics of ion transport and gating. Structural models based on homology modeling have been used successfully, but experimental structural data are currently not available. Here we determine the size of the cytosolic pore entrance by studying the blocker kinetics. Blocker binding and dissociation rate constants ranging from 0.01 to 1000 ms^-1 were determined for different quaternary ammonium ions. We found that the cytosolic pore entrance of Kcv_NTS must be at least 11 Å wide. The results further indicate that the residues controlling a cytosolic gate in one of the Kcv isoforms influence blocker binding/dissociation as well as a second gate even when the cytosolic gate is in the open state. The voltage dependence of the rate constant of blocker release is used to test, which blockers bind to the same binding site.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2402749"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11575739/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142395703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ion channel-mediated mitochondrial volume regulation and its relationship with mitochondrial dynamics.","authors":"Yujia Zhuang, Wenting Jiang, Zhe Zhao, Wencui Li, Zhiqin Deng, Jianquan Liu","doi":"10.1080/19336950.2024.2335467","DOIUrl":"10.1080/19336950.2024.2335467","url":null,"abstract":"<p><p>The mitochondrion, one of the important cellular organelles, has the major function of generating adenosine triphosphate and plays an important role in maintaining cellular homeostasis, governing signal transduction, regulating membrane potential, controlling programmed cell death and modulating cell proliferation. The dynamic balance of mitochondrial volume is an important factor required for maintaining the structural integrity of the organelle and exerting corresponding functions. Changes in the mitochondrial volume are closely reflected in a series of biological functions and pathological changes. The mitochondrial volume is controlled by the osmotic balance between the cytoplasm and the mitochondrial matrix. Thus, any disruption in the influx of the main ion, potassium, into the cells can disturb the osmotic balance between the cytoplasm and the matrix, leading to water movement between these compartments and subsequent alterations in mitochondrial volume. Recent studies have shown that mitochondrial volume homeostasis is closely implicated in a variety of diseases. In this review, we provide an overview of the main influencing factors and research progress in the field of mitochondrial volume homeostasis.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":"18 1","pages":"2335467"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10984129/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140308160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}