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Background: Fibroblast-derived exosomes can regulate the electrical remodeling of cardiomyocytes, and the intermediate-conductance calcium-activated potassium channel (KCa3.1) is important in atrial electrical remodeling. However, the underlying molecular mechanisms remain unclear. This study aimed to investigate the regulation of cardiac electrophysiology by exosomes linked to KCa3.1. Methods: Atrial myocytes (AMs) and atrial fibroblasts were isolated from Sprague-Dawley suckling rats and cultured individually. The cellular atrial fibrillation (AF) model was established via electrical stimulation (1.0 v/cm, 10 Hz), and fibroblast-derived exosomes were isolated via ultracentrifugation. Exosomes were co-cultured with AMs to investigate their influences on KCa3.1 and the underlying mechanisms. Nanoparticle tracking analysis and transmission electron microscopy were used to measure exosome particle sizes and concentrations. Whole-cell patch clamp was applied to record the current density of KCa3.1 and action potential duration (APD). The expression of miR-21-5p was detected by reverse-transcription polymerase chain reaction (RT-PCR). Western blotting or immunofluorescence was used to measure the expression of exosomal markers, Akt phosphorylation, and KCa3.1. Results: Rapid pacing promoted the secretion of exosomes from atrial fibroblasts and miR-21-5p expression in atrial fibroblasts and exosomes. KCa3.1 protein expression and current density significantly increased, and APD50 and APD90 were sharply shortened after rapid pacing in AMs. TRAM-34 (KCa3.1 blocker) extended APD and reduced susceptibility to AF. KCa3.1 and P-AKT expressions were amplified after co-culturing AMs with exosomes secreted by atrial fibroblasts. In contrast, the increase in KCa3.1 expression was reversed after the cells were co-cultured with exosomes secreted by atrial fibroblasts that were transfected with miR-21-5p inhibitors or after the use of LY294002, a PI3K/Akt pathway inhibitor. Conclusions: Rapid pacing promoted the secretion of exosomes from fibroblasts, and miR-21-5p was upregulated in exosomes. Moreover, the miR-21-5p-enriched exosomes upregulated KCa3.1 expression in AMs via the PI3K/Akt pathway.
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AIM: To explore the variance in efficacy between botulinum toxin A(BTA)injection and extraocular muscle surgery in managing large-angle(≥+60 PD)acute acquired concomitant esotropia(AACE).METHODS: A retrospective analysis was conducted on clinical data of 60 patients with AACE treated at our hospital from June 2020 to December 2022. Patients were divided into three groups based on different treatments: 2.5 IU BTA injection group(14 cases), 5.0 IU BTA injection group(29 cases), and surgical group(17 cases). Follow-up was conducted for 6 mo after treatment to observe the degree of strabismus after the correction of refractive error, visual function, treatment effectiveness, and occurrence of complications after BTA injection.RESULTS: At 6 mo post-treatment, the degree of strabismus in the surgical group and the 5.0 IU BTA injection group was lower than that in the 2.5 IU BTA injection group(P<0.017). However, there was no significant difference in the degree of strabismus between the surgical group and the 5.0 IU BTA injection group(P>0.017). The effective rate of the 5.0 IU BTA injection group was higher than that of the 2.5 IU BTA injection group(86% vs 43%, P<0.017). There was no difference in visual function among the three groups(P>0.05). The incidence of complications after treatment was not significantly different between the 2.5 IU BTA injection group and the 5.0 IU BTA injection group(43% vs 52%, P>0.05).CONCLUSION: For AACE patients with esotropia degree ≥+60 PD, bilateral medial rectus injection of 5.0 IU BTA can yield outcomes comparable to traditional extraocular muscle surgery, with the advantages of minimal trauma and simple and convenient operation.
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The leucine-rich repeat kinase 2 (LRRK2) gene was discovered to encode a member of an evolutionarily conserved family of proteins marked by GTPase domains usually in combination with kinase domains. Missense mutations in both the kinase and GTPase domains in LRRK2 have been found to cause late-onset Parkinson's disease (PD). In this study, we investigated the effects of the LRRK2 on endothelial inflammation. We first demonstrated that the LRRK2 is expressed in endothelial cells. We also report here that IL-1ß can possibly increase LRRK2 expression in human umbilical vein endothelial cells (HUVECs). Wild-type LRRK2 (LRRK2(wt)) expression induces expression of vascular cell adhesion molecule 1 (VCAM-1) which is further exacerbated in cells expressing PD-associated LRRK2 G2019S mutants (LRRK2(G2019S)). Importantly, induction of VCAM-1 is almost completely blocked in cells expressing the GTP-binding-deficient mutant K1347A of LRRK2 (LRRK2(K1347A)). In addition, overexpression of LRRK2(wt) and LRRK2(G2019S) were found to cause an increase in monocyte attachment to endothelial cells. Mechanistically, we found that LRRK2 increases the transcriptional activity of nuclear factor κB (NF-κB) by increasing phosphorylation levels of IκBα. These findings suggest that inhibition of LRRK2 kinase activity may be a potential target for treatment of endothelial dysfunction.
