LncRNA-LncDACH1 mediated phenotypic switching of smooth muscle cells during neointimal hyperplasia in male arteriovenous fistulas.

Arteriovenous fistulas (AVFs) are the most common vascular access points for hemodialysis (HD), but they have a high incidence of postoperative dysfunction, mainly due to excessive neointimal hyperplasia (NIH). Our previous studies have revealed a highly conserved LncRNA-LncDACH1 as an important regulator of cardiomyocyte and fibroblast proliferation. Herein, we find that LncDACH1 regulates NIH in AVF in male mice with conditional knockout of smooth muscle cell-specific LncDACH1 and in male mice model of AVF with LncDACH1 overexpression by adeno-associated virus. Mechanistically, silence of LncDACH1 activates p-AKT through promoting the expression of heat shock protein 90 (HSP90) and serine/arginine-rich splicing factor protein kinase 1 (SRPK1). Moreover, LncDACH1 is transcriptionally activated by transcription factor KLF9 that binds directly to the promoter region of the LncDACH1 gene. In this work, during AVF NIH, LncDACH1 is downregulated by KLF9 and promotes NIH through the HSP90/ SRPK1/ AKT signaling axis.

Effects of traditional Chinese exercises in fibromyalgia syndrome: A meta-analysis of randomized controlled trials.

OBJECTIVES: To explore the efficacy and safety of five traditional Chinese exercises (TCEs) in patients with fibromyalgia syndrome (FMS). METHODS: The PubMed, Embase, Scopus, ProQuest, Web of Science, Cochrane, CNKI, WanFang, and VIP databases were comprehensively searched for randomized controlled trials (RCTs) related to TCEs published from inception until February 2023. Standardized mean differences (SMD) and 95% confidence intervals (CI) were used to determine the combined effects of the intervention, and the Cochrane risk-of-bias assessment tool and Review 5.2 software were used to assess methodological quality. The data were extracted and analyzed by the Stata15.0 random effects model. RESULTS: Nineteen RCTs including 1315 participants were included in the analysis. The studies were found to be heterogeneous (I2 =86.2, P = 0.000), and thus a random effects model was used to combine the data. The results showed that traditional Chinese exercises had potentially beneficial effects on reducing pain (SMD =-0.66,95% CI [-1.08, -0.25], P = 0.002), improving sleep (SMD = -0.35,95% CI [-0.68,0. 01], P = 0.041) and relieving depression (SMD= -0.24,95% CI [-0.47, -0.02], P = 0.034) in FMS patients. However, no significant effects were found on improved quality of life (SMD =-0.20,95% CI [-0.48,0.09], P = 0.176). CONCLUSIONS: TCEs can improve pain, sleep quality and depression in patients with FMS and are safe. However, they do not improve the quality of life significantly. Further large-scale, high-quality, and multi-center RCTs are required to verify the efficacy of TCEs.

Bone marrow-derived exosomes promote inflammation and osteoclast differentiation in high-turnover renal osteodystrophy.

Introduction: Renal osteodystrophy (ROD) is a type of bone metabolic disorder in patients with chronic kidney disease (CKD). Inflammation is associated with bone loss in ROD. However, its precise mechanism has not yet been elucidated. The present study was conducted to investigate whether exosomes (Exos) in bone marrow (BM) are involved in the pathogenesis of high-turnover ROD.Methods: Bone mass, osteoclast number, and pro-inflammatory cytokines levels of BM supernatant were detected in adenine-induced ROD rats. The effect of Exos derived from BM (BM-Exos) of ROD (ROD-Exos) on inflammatory genes and osteoclast differentiation of BM-derived macrophages (BMMs) were further examined. Then, exosomal miRNA sequencing was performed and an miRNA-mRNA-pathway network was constructed.Results: we found increased osteoclasts and decreased bone mass in ROD rats, as well as inflammatory activation in the BM niche. Furthermore, BMMs from ROD rats displayed overproduction of proinflammatory cytokines and increased osteoclast differentiation, accompanied by nuclear factor κB (NF-κB) signaling activation. Mechanistically, we found that ROD-Exos activates NF-κB signaling to promote the release of proinflammatory cytokines and increase osteoclast differentiation of BMMs. Meanwhile, a total of 24 differentially expressed miRNAs were identified between BM-Exos from ROD and normal control (NC). The miRNA-mRNA-pathway network suggests that rno-miR-9a-5p, rno-miR-133a-3p, rno-miR-30c-5p, rno-miR-206-3p, and rno-miR-17-5p might play pivotal roles in inflammation and osteoclast differentiation. Additionally, we validated that the expression of miR-9a-5p is upregulated in ROD-Exos.Conclusion: The BM niche of ROD alters the miRNA cargo of BM-Exos to promote inflammation and osteoclast differentiation of BMMs, at least partially contributing to the pathogenesis of high-turnover ROD.

Identification of biomarkers and drug repurposing candidates based on an immune-, inflammation- and membranous glomerulonephritis-associated triplets network for membranous glomerulonephritis.

BACKGROUND: Membranous glomerulonephritis (MGN) is a common kidney disease. Despite many evidences support that many immune and inflammation-related genes could serve as effective biomarkers and treatment targets for MGN patients, the potential associations among MGN-, immune- and inflammation-related genes have not been sufficiently understood. METHODS: Here, a global immune-, inflammation- and MGN-associated triplets (IIMATs) network is constructed and analyzed. An integrated and computational approach is developed to identify dysregulated IIMATs for MGN patients based on expression and interaction data. RESULTS: 45 dysregulated IIMATs are identified in MGN by above method. Dysregulated patterns of these dysregulated IIMATs are complex and various. We identify four core clusters from dysregulated IIMATs network and some of these clusters could distinguish MGN and normal samples. Specially, some anti-cancer drugs including Tamoxifen, Bosutinib, Ponatinib and Nintedanib could become candidate drugs for MGN based on drug repurposing strategy follow IIMATs. Functional analysis shows these dysregulated IIMATs are associated with some key functions and chemokine signaling pathway. CONCLUSIONS: The present study explored the associations among immune, inflammation and MGN. Some effective candidate drugs for MGN were identified based on immune and inflammation. Overall, these comprehensive results provide novel insights into the mechanisms and treatment of MGN.

Formin mDia1 contributes to migration and epithelial-mesenchymal transition of tubular epithelial cells exposed to TGF-ß1.

Renal tubular epithelial cells may undergo epithelial-mesenchymal transition (EMT) in response to stimuli, such as transforming growth factor (TGF)-ß1, leading to myofibroblast activation and renal fibrosis. The formin mDia1 is required for nucleation and polymerization of actin and the microtubule cytoskeleton. The present study sought to explore the role of mDia1 in EMT of tubular epithelial cells. A rat model of unilateral ureteral obstruction (UUO) was established. The expression of TGF-ß1, collagen I, collagen III, and mDia1 in the kidneys was examined at day 7 after surgery. The effect of mDia1 on EMT was explored in NRK-52E cells by exposing them to TGF-ß1. Increased expression of TGF-ß1, collagen I, collagen III, and mDia1 was found in obstructive kidneys of UUO model rats. Exposing rat tubular epithelial cells to TGF-ß1 promoted collagen I and collagen III expression but had no effect on mDia1 expression. Silencing mDia1 expression impeded epithelial cell migration as well as reduced TGF-ß1, collagen, and Profilin1 expression, whereas mDia1 overexpression exerted an opposite effect. Furthermore, mDia1 regulated the expression of vimentin, α-smooth muscle actin, and E-cadherin and focal adhesion-kinase (FAK)/Src activation through Profilin1. Inhibition of the mDia1 activator RhoA by fasudil reversed EMT, and FAK/Src activation induced by mDia1. In conclusion, mDia1 regulated tubular epithelial cell migration, collagen expression, and EMT in NRK-52E cells exposed to TGF-ß1. Thus, suppression of mDia1 activation might be a strategy to counteract renal fibrosis.

TRPC6-Mediated Ca2+ Signaling is Required for Hypoxia-Induced Autophagy in Human Podocytes.

BACKGROUND/AIMS: Intracellular Ca2+ signaling plays an important role in the regulation of autophagy. However, very little is known about the role of Ca2+ influx, which is induced by plasma membrane Ca2+ channels. Our previous study showed that transient receptor potential canonical channel-6 (TRPC6), a major Ca2+ influx pathway in podocytes, was activated by hypoxia. Here, we investigated whether TRPC6 is involved in hypoxia-induced autophagy in cultured human podocytes. METHODS: In the present study, an immortalized human podocyte cell line was used. Fluo-3 fluorescence was utilized to determine intracellular Ca2+ concentration ([Ca2+]i), and western blotting was used to measure autophagy and protein expression. RESULTS: We found that blockade TRPC6 by using either TRPC6 siRNA or a TRPC6 blocker attenuated hypoxia-induced autophagy, while enhancement of TRPC6 activity with a TRPC6 activator enhanced hypoxia-induced autophagy. Furthermore, TRPC6-dependent Ca2+ signaling is responsible for hypoxia-induced autophagy since both an intracellular and extracellular Ca2+ chelator abolished hypoxia-induced autophagy. Moreover, we found that blockade of TRPC6 by using either TRPC6 siRNA or a TRPC6 blocker decreased the expression of adenosine monophosphate-activated protein kinase (AMPK), an important signaling molecule in Ca2+-dependent autophagy activation, which is activated under hypoxic conditions. These data suggest that the involvement of TRPC6 in hypoxia-induced autophagy is associated with AMPK signaling. CONCLUSION: TRPC6 is essential for hypoxia-induced autophagy in podocytes.

Risk Factor Analysis for AKI Including Laboratory Indicators: a Nationwide Multicenter Study of Hospitalized Patients.

BACKGROUND/AIMS: Risk factor studies for acute kidney injury (AKI) in China are lacking, especially those regarding non-traditional risk factors, such as laboratory indicators. METHODS: All adult patients admitted to 38 tertiary and 22 secondary hospitals in China in any one month between July and December 2014 were surveyed. AKI patients were screened according to the Kidney Disease: Improving Global Outcomes' definition of AKI. Logistic regression was used to analyze the risk factors for AKI, and Cox regression was used to analyze the risk of in-hospital mortality for AKI patients; additionally, a propensity score analysis was used to reconfirm the risk factors among laboratory indicators for mortality. RESULTS: The morbidity of AKI was 0.97%. Independent risk factors for AKI were advancing age, male gender, hypertension, and chronic kidney disease. All-cause mortality was 16.5%. The predictors of mortality in AKI patients were advancing age, tumor, higher uric acid level and increases in Acute Physiologic Assessment and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores. The hazard ratio (HR) for mortality with uric acid levels > 9.1 mg/dl compared with ≤ 5.2 mg/dl was 1.78 (95% CI: 1.23 to 2.58) for the AKI patients as a group, and was 1.73 (95% CI: 1.24 to 2.42) for a propensity score-matched set. CONCLUSION: In addition to traditional risk factors, uric acid level is an independent predictor of all-cause mortality after AKI.

Calcium-Sensing Receptor Stimulation in Cultured Glomerular Podocytes Induces TRPC6-Dependent Calcium Entry and RhoA Activation.

BACKGROUND/AIMS: Recent studies provided compelling evidence that stimulation of the calcium sensing receptor (CaSR) exerts direct renoprotective action at the glomerular podocyte level. This protective action may be attributed to the RhoA-dependent stabilization of the actin cytoskeleton. However, the underlying mechanisms remain unclear. METHODS: In the present study, an immortalized human podocyte cell line was used. Fluo-3 fluorescence was utilized to determine intracellular Ca2+ concentration ([Ca2+]i), and western blotting was used to measure canonical transient receptor potential 6 (TRPC6) protein expression and RhoA activity. Stress fibers were detected by FITC-phalloidin. RESULTS: Activating CaSR with a high extracellular Ca2+ concentration ([Ca2+]o) or R-568 (a type II CaSR agonist) induces an increase in the [Ca2+]i in a dose-dependent manner. This increase in [Ca2+]i is phospholipase C (PLC)-dependent and is smaller in the absence of extracellular Ca2+ than in the presence of 0.5 mM [Ca2+]o. The CaSR activation-induced [Ca2+]i increase is attenuated by the pharmacological blockage of TRPC6 channels or siRNA targeting TRPC6. These data suggest that TRPC6 is involved in CaSR activation-induced Ca2+ influx. Consistent with a previous study, CaSR stimulation results in an increase in RhoA activity. However, the knockdown of TRPC6 significantly abolished the RhoA activity increase induced by CaSR stimulation, suggesting that TRPC6-dependent Ca2+ entry is required for RhoA activation. The activated RhoA is involved in the formation of stress fibers and focal adhesions in response to CaSR stimulation because siRNA targeting RhoA attenuated the increase in the stress fiber mediated by CaSR stimulation. Moreover, this effect of CaSR activation on the formation of stress fibers is also abolished by the knockdown of TRPC6. CONCLUSION: TRPC6 is involved in the regulation of stress fiber formation and focal adhesions via the RhoA pathway in response to CaSR activation. This may explain the direct protective action of CaSR agonists.

The role of TRPC6 in oxidative stress-induced podocyte ischemic injury.

Increasing evidence suggests that ischemia and hypoxia serve important functions in the development of renal diseases. However, the underlying mechanism of ischemic injury has not been fully understood. In this study, we found that renal ischemia-reperfusion injury induced podocyte effacement and the upregulation of TRPC6 mRNA and protein expression. In in vitro experiments, oxygen glucose deprivation (OGD) treatment enhanced the expression of TRPC6 and TRPC6-dependent Ca(2+) influx. TRPC6 knockdown by siRNA interference attenuated the OGD-induced [Ca(2+)]i and actin assembly. OGD treatment also increased ROS production. Furthermore, inhibition of ROS activity by N-acetyl-l-cysteine (NAC) eliminated the OGD-induced increase in TRPC6 expression and Ca(2+) influx. H2O2 treatment, which results in oxidative stress, also increased TRPC6 expression and Ca(2+) influx. We conclude that TRPC6 upregulation is involved in Ca(2+) signaling and actin reorganization in podocytes after OGD. These findings provide new insight into the mechanisms underlying the cellular response of podocytes to ischemic injury.

Ulinastatin attenuates renal interstitial inflammation and inhibits fibrosis progression in rats under unilateral ureteral obstruction.

The aim of the present study was to examine the protective effects of the urinary trypsin inhibitor ulinastatin (UTI) on renal interstitial inflammation and fibrosis in rats subjected to unilateral ureteral obstruction (UUO). A total of 24 male Wistar rats were randomly divided into the three groups; the sham operation (SOR) group (n=8), the UUO group (n=8) and the UUO+UTI group (post­UUO UTI treatment, n=8). UUO was performed with complete ligation of the left ureter. As a medical intervention, saline (4 ml kg­1 d­1) and UTI (40000 units kg­1 d­1) were injected, respectively, into the animals of the corresponding groups on day one following surgery. The rats in all three groups were euthanized on day seven post surgery. Blood samples were harvested for blood urea nitrogen (BUN) and serum creatinine (Scr) content measurements. The degree of interstitial pathological changes in the tissues from the obstructed kidneys were observed through hematoxylin and eosin (H&E) and Masson staining. The CD68+ macrophage amount, tumor necrosis factor­α (TNF­α), interleukin 1ß (IL­1ß), nuclear factor­κB (NF­κB), transforming growth factor­ß1 (TGF­ß1) and type I collagen (Col­I) levels were examined immunohistochemically. The protein expression levels of NF­κB were examined using western blot analysis. Total superoxide dismutase (SOD) activity and malondialdehyde (MDA) content of homogenates were measured spectrophotometrically. The results revealed that ulinastatin had no statistically significant effect on the BUN and Scr levels (P>0.05). However, in comparison with the SOR group, the UUO group exhibited significantly more severe renal interstitial pathological injury in terms of tubular dilation, epithelial atrophy, renal interstitial inflammatory cell infiltration and proliferation of fibrous tissues, as well as significantly elevated levels of interstitial CD68+ macrophages, IL­1ß, TNF­α, NF­κB, TGF­ß1 and Col­I (P<0.01). UTI treatment significantly reduced UUO­induced renal interstitial damage with reduced levels of interstitial CD68+ macrophages, IL­1ß, TNF­α, NF­κB, TGF­ß1 and Col­I and MDA (P<0.05), and increased SOD levels (P<0.05). In conclusion, the present study indicated that UTI is able to effectively inhibit UUO­side renal interstitial inflammatory reaction and fibrosis in UUO­inflicted rats.

High glucose-induced apoptosis in cultured podocytes involves TRPC6-dependent calcium entry via the RhoA/ROCK pathway.

Increasing evidence indicates that podocyte apoptosis is a key event in the development of diabetic nephrology. However, the underlying mechanism of this apoptosis remains poorly understood. In this study, we report that high levels of glucose enhanced the expression of TRPC6 and TRPC6-dependent Ca(2+) influx, but glucose levels did not affect TRPC1 and TRPC5 expression. TRPC6 knockdown by siRNA interference attenuated the observed increase in glucose-induced podocyte apoptosis. High glucose levels also increased the generation of ROS; inhibition of ROS activity by N-acetyl-l-cysteine attenuated the high glucose-induced increase in TRPC6 expression and Ca(2+) influx. Exogenous treatment with H2O2 mimicked the high glucose response, resulting in an increase in TRPC6 expression and Ca(2+) influx. Taken together, these data suggest that high glucose levels induce ROS, thereby mediating TRPC6 expression and Ca(2+) influx. Because RhoA activity is increased following TRPC6 activation, we investigated whether TRPC6 is involved in high glucose-induced apoptosis via the RhoA/ROCK pathway. We report that high glucose levels produced an increase in RhoA activity, and this effect was abolished by the knockdown of TRPC6. Moreover, inhibition of the RhoA/ROCK pathway by a ROCK inhibitor, Y27632, also attenuated high glucose-induced apoptosis. We conclude that TRPC6 is involved in high glucose-induced podocyte apoptosis through the RhoA/ROCK pathway.

Effect of ANEPIII, a novel recombinant neurotoxic polypeptide, on sodium channels in primary cultured rat hippocampal and cortical neurons.

Previous studies have shown that the recombinant neurotoxic polypeptide BmK ANEP (ANEPIII) displayed good anti-neuroexcitation activity as demonstrated by pharmacological tests of the blockade of chemical-induced convulsive seizures. In order to search for further anticonvulsant mechanism of action of ANEPIII, the effects of ANEPIII on sodium channels were assessed using the whole-cell patch clamp recordings in primary cultures of rat hippocampal and cortical neurons. ANEPIII decreased the sodium currents in a voltage-dependent manner, which appeared as a shift of the current-voltage relation to positive potentials. The effect was reversible after washing. The concentration-responsiveness measured in hippocampal and cortical neurons revealed an IC(50) value of 124.6 nM and 192.7 nM, respectively. Furthermore, ANEPIII 1000 nM significantly shifted the activation curves of sodium current in hippocampal and cortical neurons to more positive potentials and the recovery from inactivation of sodium current was significantly slower. Voltage-dependent inactivation curves of sodium channels in hippocampal and cortical neurons did not change in the presence of 1000 nM ANEPIII. Thus, our results demonstrated that ANEPIII in submicromolar concentrations was a voltage-dependent, reversible blocker of sodium current in hippocampal and cortical neurons. It is concluded that these phenomena may explain, at least in part, the anti-neuroexciting properties of this peptide.

Circulating microRNA-1 as a potential novel biomarker for acute myocardial infarction.

Recent studies have revealed the role of microRNAs (miRNAs) in a variety of basic biological and pathological processes and the association of miRNA signatures with human diseases. Circulating miRNAs have been proposed as sensitive and informative biomarkers for multiple cancers diagnosis. We have previously documented aberrant up-regulation of miR-1 expression in ischemic myocardium and the consequent slowing of cardiac conduction. However, whether miR-1 could be a biomarker for predicting acute myocardial infarction (AMI) is unclear. In the present study, we recruited 159 patients with or without AMI for quantification of miR-1 level in plasma using real-time RT-PCR method. We performed Wilcoxon rank sum and signed rank tests for comparison. Univariable linear regression and logistics regression analyses were performed to assess the potential correlation between miR-1 and known AMI markers. We also conducted receiver-operator characteristic curve (ROC) analysis to evaluate the diagnostic ability of miR-1. We found that: miR-1 level was significantly higher in plasma from AMI patients compared with non-AMI subjects and the level was dropped to normal on discharge following medication. Increased circulating miR-1 was not associated with age, gender, blood pressure, diabetes mellitus or the established biomarkers for AMI. However, miR-1 level was well correlated with QRS by both univariable linear and logistics regression analyses. The area under ROC curve (AUC) was 0.7740 for separation between non-AMI and AMI patients and 0.8522 for separation AMI patients under hospitalization and discharge. Collectively, our results revealed that circulating miR-1 may be a novel, independent biomarker for diagnosis of AMI.

Regulation of ATP-sensitive K+ channels by caveolin-enriched microdomains in cardiac myocytes.

AIMS: ATP-sensitive potassium (K(ATP)) channels in the heart are critical regulators of cellular excitability and action potentials during ischaemia. However, little is known about subcellular localization of these channels and their regulation. The present study was designed to explore the potential role of caveolae in the regulation of K(ATP) channels in cardiac ventricular myocytes. METHODS AND RESULTS: Both adult and neonatal rat cardiomyocytes were used. Subcellular fractionation by density gradient centrifugation, western blotting, co-immunoprecipitation, and immunofluorescence confocal microscopy were employed in combination with whole-cell voltage clamp recordings and siRNA gene silencing. We detected that the majority of K(ATP) channels on the plasma membrane of cardiac myocytes were localized in caveolin-3-enriched microdomains by cell fractionation and ultracentrifugation followed by western blotting. Immunofluorescence confocal microscopy revealed extensive colocalization of K(ATP) channel pore-forming subunit Kir6.2 and caveolin-3 along the plasma membrane. Co-immunoprecipitation of cardiac myocytes showed significant association of Kir6.2, adenosine A(1) receptors, and caveolin-3. Furthermore, whole-cell voltage clamp studies suggested that adenosine A(1) receptor-mediated activation of K(ATP) channels was largely eliminated by disrupting caveolae with methyl-beta-cyclodextrin or by small interfering RNA, whereas pinacidil-induced K(ATP) activation was not altered. CONCLUSION: We demonstrate that K(ATP) channels are localized to caveolin-enriched microdomains. This microdomain association is essential for adenosine receptor-mediated regulation of K(ATP) channels in cardiac myocytes.

Protein kinase C-epsilon induces caveolin-dependent internalization of vascular adenosine 5'-triphosphate-sensitive K+ channels.

Vascular ATP-sensitive K(+) (K(ATP)) channels are critical regulators of arterial tone and, thus, blood flow in response to local metabolic needs. They are important targets for clinically used drugs to treat hypertensive emergency and angina. It is known that protein kinase C (PKC) activation inhibits K(ATP) channels in vascular smooth muscles. However, the mechanism by which PKC inhibits the channel remains unknown. Here we report that caveolin-dependent internalization is involved in PKC-epsilon-mediated inhibition of vascular K(ATP) channels (Kir6.1 and SUR2B) by phorbol 12-myristate 13-acetate or angiotensin II in human embryonic kidney 293 cells and human dermal vascular smooth muscle cells. We showed that Kir6.1 substantially overlapped with caveolin-1 at the cell surface. Cholesterol depletion with methyl-beta-cyclodextrin significantly reduced, whereas overexpression of caveolin-1 largely enhanced, PKC-induced inhibition of Kir6.1/SUR2B currents. Importantly, we demonstrated that activation of PKC-epsilon caused internalization of K(ATP) channels, the effect that was blocked by depletion of cholesterol with methyl-beta-cyclodextrin, expression of dominant-negative dynamin mutant K44E, or knockdown of caveolin-1 with small interfering RNA. Moreover, patch-clamp studies revealed that PKC-epsilon-mediated inhibition of the K(ATP) current induced by PMA or angiotensin II was reduced by a dynamin mutant, as well as small interfering RNA targeting caveolin-1. The reduction in the number of plasma membrane K(ATP) channels by PKC activation was further confirmed by cell surface biotinylation. These studies identify a novel mechanism by which the levels of vascular K(ATP) channels could be rapidly downregulated by internalization. This finding provides a novel mechanistic insight into how K(ATP) channels are regulated in vascular smooth muscle cells.

Indapamide induces apoptosis of GH3 pituitary cells independently of its inhibition of voltage-dependent K+ currents.

Indapamide blocks multiple voltage-dependent K+ currents (Kv) in the heart and Kv have an important role in cell proliferation and apoptosis, so the aim of this work was to study the effects of indapamide on Kv and the viability of GH3 cells. Indapamide inhibited Kv of GH3 cells and the inhibition was irreversible after a 10-min washout when more than 250 microM indapamide was used. Indapamide reduced the viability of GH3 cells in a concentration-dependent manner. The decreased cell viability was because indapamide induced cell apoptosis, or even necrosis at higher concentrations. HepG2 cells, which express no apparent Kv, were used to determine the association between inhibition of Kv and the apoptotic action of indapamide. Indapamide had a similar action on cell viability and apoptosis of HepG2 cells. 4-Aminopyridine, the voltage-dependent K+ channel blocker, inhibited Kv of GH3 cells but did not induce the cell apoptosis. We concluded that while indapamide inhibited Kv and induced apoptosis of GH3 cells, the apoptotic action of indapamide was not associated with its inhibition of Kv.

ANEPIII, a new recombinant neurotoxic polypeptide derived from scorpion peptide, inhibits delayed rectifier, but not A-type potassium currents in rat primary cultured hippocampal and cortical neurons.

A new recombinant neurotoxic polypeptide ANEPIII (BmK ANEPIII) derived from Scorpion peptide, which was demonstrated with antineuroexcitation properties in animal models, was examined for its action on K+ currents in primary cultured rat hippocampal and cortical neurons using the patch clamp technique in the whole-cell configuration. The delayed rectifier K+ current (I(k)) was inhibited by externally applied recombinant BmK ANEPIII, while the transient A-current (I(A)) remained virtually unaffected. BmK ANEPIII 3 microM, reduced the delayed rectifier current by 28.2% and 23.6% in cultured rat hippocampal and cortical neurons, respectively. The concentration of half-maximal block was 155.1 nM for hippocampal neurons and 227.2 nM for cortical neurons, respectively. These results suggest that BmK ANEPIII affect K+ currents, which may lead to a reduction in neuronal excitability.