Geriatric Department of The First Hospital Affiliated To AMU, Chongqing, China.
Eur Rev Med Pharmacol Sci. 2019 Apr;23(7):3021-3033. doi: 10.26355/eurrev_201904_17584.
Cardiomyocyte hypertrophy is considered to be a compensatory process of heart suffering from pathological damages. This study aimed to evaluate effects of Na+/K+ APTaseα2 (NAKα2) on isoprenaline (ISO) induced cardiomyocyte hypertrophy.
Mouse atrial cardiomyocytes were cultured and treated with ISO to establish cardiomyocyte hypertrophy model. NAKα2 over-expression and small interfere RNA (siRNA) plasmids were constructed and transfected to cardiomyocytes. Influx Ca2+ ([Ca2+]i) was measured using flow cytometry method. Fibrosis formation was examined with Masson staining. Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) staining was used to examine apoptosis. Major histocompatibility complex β (β-MHC), atrial natriuretic peptides (ANP), B-type natriuretic peptides (BNP) were evaluated with quantitative Real-time PCR (qRT-PCR). Western blot was used to detect β-MHC, ANP, BNP, Na+/Ca2+ exchanger (NCX) and L-type calcium channel (LTCC).
NAKα2 significantly inhibited NCX and LTCC expression compared to that in ISO-treated cardiomyocytes (p<0.05). NAKα2 significantly suppressed expression of β-MHC, ANP and BNP compared to that in ISO-treated cardiomyocytes (p<0.05). NAKα2 significantly alleviated fibrosis formation and inhibited apoptosis compared to that in ISO-treated cardiomyocytes (p<0.05). NAKα2 reduced intracellular calcineurin and activated phosphorylation of calcineurin-nuclear factor of activated T cells (NFAT) compared to ISO-treated cardiomyocytes (p<0.05). NAKα2 significantly strengthened effects of Klotho on ISO-induced up-regulation of hypertrophy associated molecules (p<0.05) by activating LTCC and NCX. Comparing to ISO-treated cardiomyocytes, NAKα2 combining Klotho treatment exhibited significantly better improvement of Ca2+ influx, alleviation of fibrosis and reduction of apoptosis by triggering LTCC/NCX signaling pathway.
Over-expression of NKAα2 suppressed fibrosis formation and protected against cardiomyocyte hypertrophy by inhibiting hypertrophy associated molecules, alleviating apoptosis and activating LTCC/NCX signaling pathway.
心肌细胞肥大被认为是心脏遭受病理性损伤时的一种代偿过程。本研究旨在评估钠钾三磷酸酶α2（NAKα2）对异丙肾上腺素（ISO）诱导的心肌细胞肥大的影响。
培养小鼠心房心肌细胞并使用 ISO 处理以建立心肌细胞肥大模型。构建 NAKα2 过表达和小干扰 RNA（siRNA）质粒并转染至心肌细胞。使用流式细胞术测量细胞内钙离子浓度([Ca2+]i)。使用 Masson 染色法检测纤维化形成。使用 TUNEL 染色法检测细胞凋亡。使用定量实时 PCR（qRT-PCR）评估主要组织相容性复合体β（β-MHC）、心房利钠肽（ANP）、脑利钠肽（BNP）。使用 Western blot 检测β-MHC、ANP、BNP、钠钙交换体（NCX）和 L 型钙通道（LTCC）。
与 ISO 处理的心肌细胞相比，NAKα2 显著抑制 NCX 和 LTCC 的表达（p<0.05）。与 ISO 处理的心肌细胞相比，NAKα2 显著抑制β-MHC、ANP 和 BNP 的表达（p<0.05）。与 ISO 处理的心肌细胞相比，NAKα2 显著减轻纤维化形成并抑制细胞凋亡（p<0.05）。与 ISO 处理的心肌细胞相比，NAKα2 降低钙调磷酸酶和激活钙调磷酸酶-激活 T 细胞核因子（NFAT）的磷酸化（p<0.05）。与 ISO 处理的心肌细胞相比，NAKα2 通过激活 LTCC 和 NCX 显著增强 Klotho 对 ISO 诱导的肥大相关分子的上调作用（p<0.05）。与 ISO 处理的心肌细胞相比，NAKα2 联合 Klotho 治疗通过触发 LTCC/NCX 信号通路显著改善 Ca2+ 内流、减轻纤维化和减少细胞凋亡。
过表达 NKAα2 通过抑制肥大相关分子、减轻细胞凋亡和激活 LTCC/NCX 信号通路，抑制纤维化形成并保护心肌细胞免受心肌肥大的影响。
