RESUMO
An increasing body of evidence suggests that acylphosphatase-2 (ACYP2) polymorphisms are correlated with an increased susceptibility to a range of malignancies. Nevertheless, its potential functions, molecular mechanisms in hepatocellular carcinoma (HCC) and whether it can be act as a therapeutic target remain uninvestigated. Herein, ACYP2 was found to be lowly expressed in HCC and was negatively correlated with tumor size, tumor differentiation, microvascular invasion and the prognosis of HCC patients. Functional investigations revealed that overexpression of ACYP2 inhibited the proliferation and metastasis of HCC cells while promoting apoptosis; knockdown of ACYP2 had the exact opposite effect. Additionally, it was observed that ACYP2 was distributed in both the cytoplasm and nucleus of HCC cells. According to the mechanistic studies, the expression of potassium calcium-activated channel subfamily N member 4 (KCNN4) was negatively regulated by cytoplasmic ACYP2, resulting in the inhibition of K+ outflow and subsequent inactivation of the ERK pathway, which impeded the growth and metastasis of HCC. Furthermore, the activity of telomerase reverse transcriptase (TERT) was inhibited by nuclear ACYP2, leading to the reduction in length of telomeres and consequent reversal of HCC cell immortalization. Additionally, a novel targeted nanotherapy strategy was developed wherein the pcDNA-ACYP2 vector was encapsulated within polyetherimide nanoparticles (PEI/NPs), which were subsequently coated with HCC cell membranes (namely pcDNA/PEI/NPs@M). Safety and targeting characteristics abound for these nanocomposites, in both subcutaneous graft tumor models and orthotopic mouse models, they inhibited the progression of HCC by impeding TERT activity and the KCNN4/ERK pathway. In conclusion, our research identifies novel molecular mechanisms involving cytoplasmic and nuclear ACYP2 that inhibit the progression of HCC. Moreover, pcDNA/PEI/NPs@M represents a targeted therapeutic strategy for HCC that holds great promising.
Assuntos
Carcinoma Hepatocelular , Proliferação de Células , Canais de Potássio Ativados por Cálcio de Condutância Intermediária , Neoplasias Hepáticas , Sistema de Sinalização das MAP Quinases , Telomerase , Humanos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Telomerase/metabolismo , Telomerase/genética , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Camundongos , Masculino , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/antagonistas & inibidores , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos Nus , Apoptose/efeitos dos fármacos , Feminino , Progressão da Doença , Camundongos Endogâmicos BALB C , Nanopartículas/química , Pessoa de Meia-IdadeRESUMO
Peripheral nerve injury-induced neuronal hyperactivity in the dorsal root ganglion (DRG) participates in neuropathic pain. The calcium-activated potassium channel subfamily N member 1 (KCNN1) mediates action potential afterhyperpolarization (AHP) and gates neuronal excitability. However, the specific contribution of DRG KCNN1 to neuropathic pain is not yet clear. We report that chronic constriction injury (CCI) of the unilateral sciatic nerve or unilateral ligation of the fourth lumbar nerve produced the downregulation of Kcnn1 mRNA and KCNN1 protein in the injured DRG. This downregulation was partially attributed to a decrease in DRG estrogen-related receptor gamma (ESRRG), a transcription factor, which led to reduced binding to the Kcnn1 promoter. Rescuing this downregulation prevented CCI-induced decreases in total potassium voltage currents and AHP currents, reduced excitability in the injured DRG neurons, and alleviated CCI-induced development and maintenance of nociceptive hypersensitivities, without affecting locomotor function and acute pain. Mimicking the CCI-induced DRG KCNN1 downregulation resulted in augmented responses to mechanical, heat, and cold stimuli in naive mice. Our findings indicate that ESRRG-controlled downregulation of DRG KCNN1 is likely essential for the development and maintenance of neuropathic pain. Thus, KCNN1 may serve as a potential target for managing this disorder.
Assuntos
Regulação para Baixo , Gânglios Espinais , Neuralgia , Células Receptoras Sensoriais , Animais , Masculino , Camundongos , Potenciais de Ação , Modelos Animais de Doenças , Gânglios Espinais/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Camundongos Endogâmicos C57BL , Neuralgia/metabolismo , Neuralgia/genética , Traumatismos dos Nervos Periféricos/metabolismo , Traumatismos dos Nervos Periféricos/genética , Nervo Isquiático/lesões , Nervo Isquiático/metabolismo , Células Receptoras Sensoriais/metabolismoRESUMO
The tumor suppressor gene F-box and WD repeat domain-containing (FBXW) 7 reduces cancer stemness properties by promoting the protein degradation of pluripotent stem cell markers. We recently demonstrated the transcriptional repression of FBXW7 by the three-dimensional (3D) spheroid formation of several cancer cells. In the present study, we found that the transcriptional activity of FBXW7 was promoted by the inhibition of the Ca2+-activated K+ channel, KCa1.1, in a 3D spheroid model of human prostate cancer LNCaP cells through the Akt-Nrf2 signaling pathway. The transcriptional activity of FBXW7 was reduced by the siRNA-mediated inhibition of the CCAAT-enhancer-binding protein C/EBP δ (CEBPD) after the transfection of miR223 mimics in the LNCaP spheroid model, suggesting the transcriptional regulation of FBXW7 through the Akt-Nrf2-CEBPD-miR223 transcriptional axis in the LNCaP spheroid model. Furthermore, the KCa1.1 inhibition-induced activation of FBXW7 reduced (1) KCa1.1 activity and protein levels in the plasma membrane and (2) the protein level of the cancer stem cell (CSC) markers, c-Myc, which is a molecule degraded by FBXW7, in the LNCaP spheroid model, indicating that KCa1.1 inhibition-induced FBXW7 activation suppressed CSC conversion in KCa1.1-positive cancer cells.
Assuntos
Proteína 7 com Repetições F-Box-WD , Regulação Neoplásica da Expressão Gênica , Fator 2 Relacionado a NF-E2 , Neoplasias da Próstata , Transdução de Sinais , Esferoides Celulares , Humanos , Proteína 7 com Repetições F-Box-WD/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Masculino , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Esferoides Celulares/metabolismo , Linhagem Celular Tumoral , Regulação para Cima , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/antagonistas & inibidores , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismoRESUMO
Anomalous expression of potassium channels in cancer tissues is associated with several cancer hallmarks that support deregulated proliferation and tumor progression. Ion channels seem to influence cell proliferation; however, the crucial molecular mechanisms involved remain elusive. Some results show how extracellular mitogenic signals modulate ion channel activity through intracellular secondary messengers. It is relevant because we are beginning to understand how potassium channels can affect the proliferative capacity of cells, either in normal mitogen-dependent proliferation or in mitogen-unresponsive proliferation. Calciumdependent potassium channels have been implicated in cell cycle signaling in many cancerous cell lines. In particular, the so-called intermediate conductance KCa3.1 (IKCa) is reported to play a significant role in uncontrolled cell cycle signaling, among other malignant processes driven by cancer hallmarks. In addition to these features, this channel can be subjected to specific pharmacological regulation, making it a promising cornerstone for understanding the signaling behavior of several types of cancer and as a target for chemotherapeutic approaches. This review is dedicated to the connection of KCa3.1 activity, in canonical and non-canonical ways, to the cell cycle signaling, including the cooperation with calcium channels to generate calcium signals and its role as a mediator of proliferative signals.
Assuntos
Canais de Potássio Ativados por Cálcio de Condutância Intermediária , Neoplasias , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Mitógenos , Proliferação de Células , Canais IônicosRESUMO
The expression of IKCa (SK4) channel subunits overlaps with that of SK channel subunits, and it has been proposed that the two related subunits prefer to co-assemble to form heteromeric hSK1:hIKCa channels. This implicates hSK1:hIKCa heteromers in physiological roles that might have been attributed to activation of SK channels. We have used a mutation approach to confirm formation of heterometric hSK1:hIKCa channels. Introduction of residues within hSK1 that were predicted to impart sensitivity to the hIKCa current blocker TRAM-34 changed the pharmacology of functional heteromers. Heteromeric channels formed between wildtype hIKCa and mutant hSK1 subunits displayed a significantly higher sensitivity and maximum block to addition of TRAM-34 than heteromers formed between wildtype subunits. Heteromer formation was disrupted by a single point mutation within one COOH-terminal coiled-coil domain of the hIKCa channel subunit. This mutation only disrupted the formation of hSK1:hIKCa heteromeric channels, without affecting the formation of homomeric hIKCa channels. Finally, the Ca2+ gating sensitivity of heteromeric hSK1:hIKCa channels was found to be significantly lower than the Ca2+ gating sensitivity of homomeric hIKCa channels. These data confirmed the preferred formation of heteromeric channels that results from COOH-terminal interactions between subunits. The distinct sensitivity of the heteromer to activation by Ca2+ suggests that heteromeric channels fulfil a distinct function within those neurons that express both subunits.
Assuntos
Canais de Potássio Ativados por Cálcio de Condutância Intermediária , Neurônios , Canais de Potássio Ativados por Cálcio de Condutância Baixa , Mutação , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/fisiologia , Canais de Potássio Ativados por Cálcio de Condutância Baixa/genética , Canais de Potássio Ativados por Cálcio de Condutância Baixa/fisiologiaRESUMO
Gene therapy offers a potential alternative to the surgical treatment of epilepsy, which affects millions of people and is pharmacoresistant in ~30% of cases. Aimed at reducing the excitability of principal neurons, the engineered expression of K+ channels has been proposed as a treatment due to the outstanding ability of K+ channels to hyperpolarize neurons. However, the effects of K+ channel overexpression on cell physiology remain to be investigated. Here we report an adeno-associated virus (AAV) vector designed to reduce epileptiform activity specifically in excitatory pyramidal neurons by expressing the human Ca2+-gated K+ channel KCNN4 (KCa3.1). Electrophysiological and pharmacological experiments in acute brain slices showed that KCNN4-transduced cells exhibited a Ca2+-dependent slow afterhyperpolarization that significantly decreased the ability of KCNN4-positive neurons to generate high-frequency spike trains without affecting their lower-frequency coding ability and action potential shapes. Antiepileptic activity tests showed potent suppression of pharmacologically induced seizures in vitro at both single cell and local field potential levels with decreased spiking during ictal discharges. Taken together, our findings strongly suggest that the AAV-based expression of the KCNN4 channel in excitatory neurons is a promising therapeutic intervention as gene therapy for epilepsy.
Assuntos
Epilepsia , Neurônios , Humanos , Neurônios/metabolismo , Potenciais de Ação/fisiologia , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/farmacologiaRESUMO
The intermediate-conductance calcium-activated potassium channel KCa3.1 has been proposed to be a new potential target for glioblastoma treatment. This study analyzed the effect of combined irradiation and KCa3.1-targeting with TRAM-34 in the syngeneic, immune-competent orthotopic SMA-560/VM/Dk glioma mouse model. Whereas neither irradiation nor TRAM-34 treatment alone meaningfully prolonged the survival of the animals, the combination significantly prolonged the survival of the mice. We found an irradiation-induced hyperinvasion of glioma cells into the brain, which was inhibited by concomitant TRAM-34 treatment. Interestingly, TRAM-34 did neither radiosensitize nor impair SMA-560's intrinsic migratory capacities in vitro. Exploratory findings hint at increased TGF-ß1 signaling after irradiation. On top, we found a marginal upregulation of MMP9 mRNA, which was inhibited by TRAM-34. Last, infiltration of CD3+, CD8+ or FoxP3+ T cells was not impacted by either irradiation or KCa3.1 targeting and we found no evidence of adverse events of the combined treatment. We conclude that concomitant irradiation and TRAM-34 treatment is efficacious in this preclinical glioma model.
Assuntos
Glioblastoma , Glioma , Camundongos , Animais , Glioma/tratamento farmacológico , Glioma/radioterapia , Modelos Animais de Doenças , Pirazóis/farmacologia , Pirazóis/uso terapêutico , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genéticaRESUMO
BACKGROUND: S1P (sphingosine-1-phosphate) has been reported to possess vasodilatory properties, but the underlying pathways are largely unknown. METHODS: Isolated mouse mesenteric artery and endothelial cell models were used to determine S1P-induced vasodilation, intracellular calcium, membrane potentials, and calcium-activated potassium channels (KCa2.3 and KCa3.1 [endothelial small- and intermediate-conductance calcium-activated potassium channels]). Effect of deletion of endothelial S1PR1 (type 1 S1P receptor) on vasodilation and blood pressure was evaluated. RESULTS: Mesenteric arteries subjected to acute S1P stimulation displayed a dose-dependent vasodilation response, which was attenuated by blocking endothelial KCa2.3 or KCa3.1 channels. In cultured human umbilical vein endothelial cells, S1P stimulated immediate membrane potential hyperpolarization following activation of KCa2.3/KCa3.1 with elevated cytosolic Ca2+. Further, chronic S1P stimulation enhanced expression of KCa2.3 and KCa3.1 in human umbilical vein endothelial cells in dose- and time-dependent manners, which was abolished by disrupting either S1PR1-Ca2+ signaling or downstream Ca2+-activated calcineurin/NFAT (nuclear factor of activated T-cells) signaling. By combination of bioinformatics-based binding site prediction and chromatin immunoprecipitation assay, we revealed in human umbilical vein endothelial cells that chronic activation of S1P/S1PR1 promoted NFATc2 nuclear translocation and binding to promoter regions of KCa2.3 and KCa3.1 genes thus to upregulate transcription of these channels. Deletion of endothelial S1PR1 reduced expression of KCa2.3 and KCa3.1 in mesenteric arteries and exacerbated hypertension in mice with angiotensin II infusion. CONCLUSIONS: This study provides evidence for the mechanistic role of KCa2.3/KCa3.1-activated endothelium-dependent hyperpolarization in vasodilation and blood pressure homeostasis in response to S1P. This mechanistic demonstration would facilitate the development of new therapies for cardiovascular diseases associated with hypertension.
Assuntos
Hipertensão , Vasodilatação , Camundongos , Humanos , Animais , Pressão Sanguínea , Endotélio/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Homeostase , Canais de Potássio Ativados por Cálcio de Condutância Baixa/genética , Canais de Potássio Ativados por Cálcio de Condutância Baixa/metabolismoRESUMO
Small- and intermediate-conductance Ca2+-activated K+ (KCa2.x/KCa3.1 also called SK/IK) channels are gated exclusively by intracellular Ca2+. The Ca2+ binding protein calmodulin confers sub-micromolar Ca2+ sensitivity to the channel-calmodulin complex. The calmodulin C-lobe is constitutively associated with the proximal C-terminus of the channel. Interactions between calmodulin N-lobe and the channel S4-S5 linker are Ca2+-dependent, which subsequently trigger conformational changes in the channel pore and open the gate. KCNN genes encode four subtypes, including KCNN1 for KCa2.1 (SK1), KCNN2 for KCa2.2 (SK2), KCNN3 for KCa2.3 (SK3), and KCNN4 for KCa3.1 (IK). The three KCa2.x channel subtypes are expressed in the central nervous system and the heart. The KCa3.1 subtype is expressed in the erythrocytes and the lymphocytes, among other peripheral tissues. The impact of dysfunctional KCa2.x/KCa3.1 channels on human health has not been well documented. Human loss-of-function KCa2.2 mutations have been linked with neurodevelopmental disorders. Human gain-of-function mutations that increase the apparent Ca2+ sensitivity of KCa2.3 and KCa3.1 channels have been associated with Zimmermann-Laband syndrome and hereditary xerocytosis, respectively. This review article discusses the physiological significance of KCa2.x/KCa3.1 channels, the pathophysiology of the diseases linked with KCa2.x/KCa3.1 mutations, the structure-function relationship of the mutant KCa2.x/KCa3.1 channels, and potential pharmacological therapeutics for the KCa2.x/KCa3.1 channelopathy.
Assuntos
Canalopatias , Canais de Potássio Ativados por Cálcio de Condutância Baixa , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Baixa/genética , Canais de Potássio Ativados por Cálcio de Condutância Baixa/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Calmodulina/genética , Calmodulina/metabolismo , MutaçãoRESUMO
Ion channels are non-conventional, druggable oncological targets. The intermediate-conductance calcium-dependent potassium channel (KCa3.1) is highly expressed in the plasma membrane and in the inner mitochondrial membrane (mitoKCa3.1) of various cancer cell lines. The role mitoKCa3.1 plays in cancer cells is still undefined. Here we report the synthesis and characterization of two mitochondria-targeted novel derivatives of a high-affinity KCa3.1 antagonist, TRAM-34, which retain the ability to block channel activity. The effects of these drugs were tested in melanoma, pancreatic ductal adenocarcinoma and breast cancer lines, as well as in vivo in two orthotopic models. We show that the mitochondria-targeted TRAM-34 derivatives induce release of mitochondrial reactive oxygen species, rapid depolarization of the mitochondrial membrane, fragmentation of the mitochondrial network. They trigger cancer cell death with an EC50 in the µM range, depending on channel expression. In contrast, inhibition of the plasma membrane KCa3.1 by membrane-impermeant Maurotoxin is without effect, indicating a specific role of mitoKCa3.1 in determining cell fate. At sub-lethal concentrations, pharmacological targeting of mitoKCa3.1 significantly reduced cancer cell migration by enhancing production of mitochondrial reactive oxygen species and nuclear factor-κB (NF-κB) activation, and by downregulating expression of Bcl-2 Nineteen kD-Interacting Protein (BNIP-3) and of Rho GTPase CDC-42. This signaling cascade finally leads to cytoskeletal reorganization and impaired migration. Overexpression of BNIP-3 or pharmacological modulation of NF-κB and CDC-42 prevented the migration-reducing effect of mitoTRAM-34. In orthotopic models of melanoma and pancreatic ductal adenocarcinoma, the tumors at sacrifice were 60% smaller in treated versus untreated animals. Metastasis of melanoma cells to lymph nodes was also drastically reduced. No signs of toxicity were observed. In summary, our results identify mitochondrial KCa3.1 as an unexpected player in cancer cell migration and show that its pharmacological targeting is efficient against both tumor growth and metastatic spread in vivo.
Assuntos
Carcinoma Ductal Pancreático , Melanoma , Neoplasias Pancreáticas , Canais de Potássio Cálcio-Ativados , Animais , NF-kappa B/metabolismo , Cálcio/metabolismo , Canais de Cálcio , Canais de Potássio , Espécies Reativas de Oxigênio/metabolismo , Morte Celular , Mitocôndrias/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Neoplasias PancreáticasRESUMO
Peptide Lv is a small endogenous secretory peptide that is expressed in various tissues and conserved across different species. Patients with diabetic retinopathy, an ocular disease with pathological angiogenesis, have upregulated peptide Lv in their retinas. The pro-angiogenic activity of peptide Lv is in part through promoting vascular endothelial cell (EC) proliferation, migration, and sprouting, but its molecular mechanism is not completely understood. This study aimed to decipher how peptide Lv promotes EC-dependent angiogenesis by using patch-clamp electrophysiological recordings, Western immunoblotting, quantitative PCR, and cell proliferation assays in cultured ECs. Endothelial cells treated with peptide Lv became significantly hyperpolarized, an essential step for EC activation. Treatment with peptide Lv augmented the expression and current densities of the intermediate-conductance calcium-dependent potassium (KCa3.1) channels that contribute to EC hyperpolarization but did not augment other potassium channels. Blocking KCa3.1 attenuated peptide Lv-elicited EC proliferation. These results indicate that peptide Lv-stimulated increases of functional KCa3.1 in ECs contributes to EC activation and EC-dependent angiogenesis.
Assuntos
Células Endoteliais , Canais de Potássio Ativados por Cálcio de Condutância Intermediária , Humanos , Células Endoteliais/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Cálcio/metabolismo , Neovascularização Patológica/metabolismo , Peptídeos/metabolismo , Potássio/metabolismoRESUMO
Red cell volume is a major determinant of HbS concentration in sickle cell disease. Cellular deoxy-HbS concentration determines the delay time, the interval between HbS deoxygenation and deoxy-HbS polymerization. Major membrane transporter protein determinants of sickle red cell volume include the SLC12/KCC K-Cl cotransporters KCC3/SLC12A6 and KCC1/SLC12A4, and the KCNN4/KCa3.1 Ca2+-activated K+ channel (Gardos channel). Among standard inhibitors of KCC-mediated K-Cl cotransport, only [(dihydroindenyl)oxy]acetic acid (DIOA) has been reported to lack inhibitory activity against the related bumetanide-sensitive erythroid Na-K-2Cl cotransporter NKCC1/SLC12A2. DIOA has been often used to inhibit K-Cl cotransport when studying the expression and regulation of other K+ transporters and K+ channels. We report here that DIOA at concentrations routinely used to inhibit K-Cl cotransport can also abrogate activity of the KCNN4/KCa3.1 Gardos channel in human and mouse red cells and in human sickle red cells. DIOA inhibition of A23187-stimulated erythroid K+ uptake (Gardos channel activity) was chloride-independent and persisted in mouse red cells genetically devoid of the principal K-Cl cotransporters KCC3 and KCC1. DIOA also inhibited YODA1-stimulated, chloride-independent erythroid K+ uptake. In contrast, DIOA exhibited no inhibitory effect on K+ influx into A23187-treated red cells of Kcnn4-/- mice. DIOA inhibition of human KCa3.1 was validated (IC50 42 µM) by whole cell patch clamp in HEK-293 cells. RosettaLigand docking experiments identified a potential binding site for DIOA in the fenestration region of human KCa3.1. We conclude that DIOA at concentrations routinely used to inhibit K-Cl cotransport can also block the KCNN4/KCa3.1 Gardos channel in normal and sickle red cells.
Assuntos
Anemia Falciforme , Simportadores , Ácido Acético , Anemia Falciforme/tratamento farmacológico , Animais , Calcimicina , Cloretos/metabolismo , Células HEK293 , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Camundongos , Potássio/metabolismo , Membro 2 da Família 12 de Carreador de Soluto , Simportadores/metabolismoRESUMO
Small- and intermediate-conductance Ca2+-activated potassium (KCa2.x and KCa3.1, also called SK and IK) channels are activated exclusively by a Ca2+-calmodulin gating mechanism. Wild-type KCa2.3 channels have a Ca2+ EC50 value of â¼0.3 µM, while the apparent Ca2+ sensitivity of wild-type KCa3.1 channels is â¼0.27 µM. Heterozygous genetic mutations of KCa2.3 channels have been associated with Zimmermann-Laband syndrome and idiopathic noncirrhotic portal hypertension, while KCa3.1 channel mutations were reported in hereditary xerocytosis patients. KCa2.3_S436C and KCa2.3_V450L channels with mutations in the S45A/S45B helices exhibited hypersensitivity to Ca2+. The corresponding mutations in KCa3.1 channels also elevated the apparent Ca2+ sensitivity. KCa3.1_S314P, KCa3.1_A322V and KCa3.1_R352H channels with mutations in the HA/HB helices are hypersensitive to Ca2+, whereas KCa2.3 channels with the equivalent mutations are not. The different effects of the equivalent mutations in the HA/HB helices on the apparent Ca2+ sensitivity of KCa2.3 and KCa3.1 channels may imply distinct modulation of the two channel subtypes by the HA/HB helices. AP14145 reduced the apparent Ca2+ sensitivity of the hypersensitive mutant KCa2.3 channels, suggesting the potential therapeutic usefulness of negative gating modulators.
Assuntos
Canalopatias , Canais de Potássio Ativados por Cálcio de Condutância Intermediária , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Mutação/genética , Canais de Potássio Ativados por Cálcio de Condutância Baixa/genéticaRESUMO
Calcium signaling plays a vital role in the regulation of various cellular processes, including activation, proliferation, and differentiation of T-lymphocytes, which is mediated by ORAI1 and potassium (K+) channels. These channels have also been identified as highly attractive therapeutic targets for immune-related diseases. Licochalcone A is a licorice-derived chalconoid known for its multifaceted beneficial effects in pharmacological treatments, including its anti-inflammatory, anti-asthmatic, antioxidant, antimicrobial, and antitumorigenic properties. However, its anti-inflammatory effects involving ion channels in lymphocytes remain unclear. Thus, the present study aimed to investigate whether licochalcone A inhibits ORAI1 and K+ channels in T-lymphocytes. Our results indicated that licochalcone A suppressed all three channels (ORAI1, Kv1.3, and KCa3.1) in a concentration-dependent matter, with IC50 values of 2.97 ± 1.217 µM, 0.83 ± 1.222 µM, and 11.21 ± 1.07 µM, respectively. Of note, licochalcone A exerted its suppressive effects on the IL-2 secretion and proliferation in CD3 and CD28 antibody-induced T-cells. These results indicate that the use of licochalcone A may provide an effective treatment strategy for inflammation-related immune diseases.
Assuntos
Anti-Inflamatórios/farmacologia , Chalconas/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/antagonistas & inibidores , Canal de Potássio Kv1.3/antagonistas & inibidores , Proteína ORAI1/antagonistas & inibidores , Linfócitos T/efeitos dos fármacos , Cálcio/metabolismo , Sinalização do Cálcio , Células HEK293 , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Células Jurkat , Canal de Potássio Kv1.3/genética , Canal de Potássio Kv1.3/metabolismo , Proteína ORAI1/genética , Proteína ORAI1/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismoRESUMO
We have shown that calcium-activated potassium (KCa)-channels regulate fundamental progenitor-cell functions, including proliferation, but their contribution to cell-therapy effectiveness is unknown. Here, we test the participation of KCa-channels in human heart explant-derived cell (EDC) physiology and therapeutic potential. TRAM34-sensitive KCa3.1-channels, encoded by the KCNN4 gene, are exclusively expressed in therapeutically bioactive EDC subfractions and maintain a strongly polarized resting potential; whereas therapeutically inert EDCs lack KCa3.1 channels and exhibit depolarized resting potentials. Somatic gene transfer of KCNN4 results in membrane hyperpolarization and increases intracellular [Ca2+], which boosts cell-proliferation and the production of pro-healing cytokines/nanoparticles. Intramyocardial injection of EDCs after KCNN4-gene overexpression markedly increases the salutary effects of EDCs on cardiac function, viable myocardium and peri-infarct neovascularization in a well-established murine model of ischemic cardiomyopathy. Thus, electrophysiological engineering provides a potentially valuable strategy to improve the therapeutic value of progenitor cells for cardioprotection and possibly other indications.
Assuntos
Cálcio/metabolismo , Terapia Baseada em Transplante de Células e Tecidos/métodos , Fenômenos Eletrofisiológicos , Coração , Canais de Potássio Cálcio-Ativados/metabolismo , Potássio/metabolismo , Animais , Proliferação de Células/efeitos dos fármacos , Citocinas , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Regulação da Expressão Gênica , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Isquemia , Potenciais da Membrana/fisiologia , Camundongos , Miocárdio/metabolismo , Nanopartículas , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Cálcio-Ativados/genética , Células-TroncoRESUMO
OBJECTIVE: In order to find new strategies for the prevention of vascular calcification in uremic individuals especially treated by dialysis and develop novel therapeutic targets in vascular calcification, we explore the role of KCa3.1 in alkalinization-induced VSMCs calcification in vitro. METHOD: Rat VSMCs calcification model was established by beta-glycerophosphate (ß-GP, 10 mM) induction. The pH of Dulbecco's modified Eagle's medium (DMEM) was adjusted every 24 h with 10 mM HCl or 10 mM NaHCO3 . The mineralization was measured by Alizarin Red staining and O-cresolphthalein complex one method. mRNA and protein expression were detected by RT-PCR and Western blot or immunofluorescence. Ca2+ influx was measured by Elisa. RESULT: The results indicated that alkalization induced an increase in Ca2+ influx to enhance VSMCs calcification. Furthermore, the increase of calcification was associated with the expression of KCa3.1 via advanced expression of osteoblastic differentiation markers alkaline phosphatase (ALP) and Runt-related transcription factor 2 (Runx2). Blocking KCa3.1 with TRAM-34 or shRNA vector can significantly lowered the effects of calcification in the activity of ALP and Runx2 expression. CONCLUSION: Together all, our studies suggested that alkalinization can promote vascular calcification by upregulating KCa3.1 channel and enhancing osteogenic/chondrogenic differentiation by upregulating Runx2. The specific inhibitor TRAM-34 and KCa3.1-shRNA ameliorated VSMCs calcification by downregulating KCa3.1.
Assuntos
Aorta/patologia , Calcinose/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Fosfatase Alcalina/metabolismo , Animais , Aorta/efeitos dos fármacos , Aorta/metabolismo , Calcinose/induzido quimicamente , Calcinose/tratamento farmacológico , Cálcio/metabolismo , Células Cultivadas , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Glicerofosfatos/toxicidade , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/antagonistas & inibidores , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Masculino , Músculo Liso Vascular/química , Músculo Liso Vascular/citologia , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Pirazóis/farmacologia , Ratos Sprague-DawleyAssuntos
Canalopatias/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Trombose/genética , Anemia Hemolítica Congênita/complicações , Anemia Hemolítica Congênita/genética , Anemia Hemolítica Congênita/patologia , Canalopatias/complicações , Canalopatias/patologia , Eritrócitos/patologia , Mutação com Ganho de Função , Hemólise , Humanos , Masculino , Pessoa de Meia-Idade , Mutação Puntual , Trombose/complicações , Trombose/patologiaRESUMO
The population of regulatory T cells (Tregs) is critical for immunological self-tolerance and homeostasis. Proper ion regulation contributes to Treg lineage identity, regulation, and effector function. Identified ion channels include Ca2+ release-activated Ca2+, transient receptor potential, P2X, volume-regulated anion and K+ channels Kv1.3 and KCa3.1. Ion channel modulation represents a promising therapeutic approach for the treatment of autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. This review summarizes studies with gene-targeted mice and pharmacological modulators affecting Treg number and function. Furthermore, participation of ion channels is illustrated and the power of future research possibilities is discussed.
Assuntos
Artrite Reumatoide/tratamento farmacológico , Cálcio/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Moduladores de Transporte de Membrana/farmacologia , Esclerose Múltipla/tratamento farmacológico , Linfócitos T Reguladores/efeitos dos fármacos , Animais , Artrite Reumatoide/genética , Artrite Reumatoide/imunologia , Artrite Reumatoide/metabolismo , Cálcio/imunologia , Canais de Cálcio Ativados pela Liberação de Cálcio/genética , Canais de Cálcio Ativados pela Liberação de Cálcio/imunologia , Sinalização do Cálcio , Modelos Animais de Doenças , Regulação da Expressão Gênica/imunologia , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/imunologia , Canal de Potássio Kv1.3/genética , Canal de Potássio Kv1.3/imunologia , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Moduladores de Transporte de Membrana/química , Camundongos , Esclerose Múltipla/genética , Esclerose Múltipla/imunologia , Esclerose Múltipla/metabolismo , Receptores Purinérgicos P2X/genética , Receptores Purinérgicos P2X/imunologia , Receptores Purinérgicos P2X7/genética , Receptores Purinérgicos P2X7/imunologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/patologia , Canais de Potencial de Receptor Transitório/genética , Canais de Potencial de Receptor Transitório/imunologiaRESUMO
Hypertrophic scars are the most common post-burn complications characterized by fibroblast proliferation and excessive extracellular matrix deposition. The intermediate-conductance Ca2+-activated K+ channel (KCa3.1) mediates fibroblast activation, resulting in several fibrotic diseases; however, this channel's role in the formation of post-burn hypertrophic skin scars remains unknown. Herein, we investigated the role of KCa3.1 and the therapeutic potential of TRAM-34, a selective inhibitor of KCa3.1, in hypertrophic skin scar formation following burn injury. Cytosolic Ca2+ levels, the expression of KCa3.1 and hypertrophic markers, and the proliferation of skin fibroblasts obtained directly from patients with third-degree burns who consequently developed post-burn hypertrophic scars were assessed. The anti-fibrotic effect of KCa3.1 inhibition by TRAM-34 was evaluated in vitro (fibroblasts) and in vivo (mouse burn models). Fibroblasts from burn wounds exhibited remarkably higher levels of cytosolic Ca2+ than normal cells. KCa3.1 expression was markedly higher in the membrane fraction but lower in the cytosolic fraction of burn wound fibroblasts than in normal cells. Selective inhibition of KCa3.1 by TRAM-34 markedly reduced not only the proliferation of burn wound fibroblasts but also the expression of hypertrophic markers in these cells. Anti-scarring molecular, histological, and visual effects of TRAM-34 were confirmed in murine burn models. Altered subcellular expression of KCa3.1 is a novel mechanism underlying the cellular response to burn injury. Our results suggest that selective inhibition of KCa3.1 by TRAM-34 has therapeutic potential against post-burn hypertrophic scar formation.