Regulation of Na+-K+-ATPase leads to disturbances of isoproterenol-induced cardiac dysfunction via interference of Ca2+-dependent cardiac metabolism.

Reductions in Na+-K+-ATPase (NKA) activity and expression are often observed in the progress of various reason-induced heart failure (HF). However, NKA α1 mutation or knockdown cannot cause spontaneous heart disease. Whether the abnormal NKA α1 directly contributes to HF pathogenesis remains unknown. Here, we challenge NKA α1+/- mice with isoproterenol to evaluate the role of NKA α1 haploinsufficiency in isoproterenol (ISO)-induced cardiac dysfunction. Genetic knockdown of NKA α1 accelerated ISO-induced cardiac cell hypertrophy, heart fibrosis, and dysfunction. Further studies revealed decreased Krebs cycle, fatty acid oxidation, and mitochondrial OXPHOS in the hearts of NKA α1+/- mice challenged with ISO. In ISO-treated conditions, inhibition of NKA elevated cytosolic Na+, further reduced mitochondrial Ca2+ via mNCE, and then finally down-regulated cardiac cell energy metabolism. In addition, a supplement of DRm217 alleviated ISO-induced heart dysfunction, mitigated cardiac remodeling, and improved cytosolic Na+ and Ca2+ elevation and mitochondrial Ca2+ depression in the NKA α1+/- mouse model. The findings suggest that targeting NKA and mitochondria Ca2+ could be a promising strategy in the treatment of heart disease.

Quercitrin alleviates lipid metabolism disorder in polycystic ovary syndrome-insulin resistance by upregulating PM20D1 in the PI3K/Akt pathway.

BACKGROUND: Abnormal endocrine metabolism caused by polycystic ovary syndrome combined with insulin resistance (PCOS-IR) poses a serious risk to reproductive health in females. Quercitrin is a flavonoid that can efficiently improve both endocrine and metabolic abnormalities. However, it remains unclear if this agent can exert therapeutic effect on PCOS-IR. METHODS: The present study used a combination of metabolomic and bioinformatic methods to screen key molecules and pathways involved in PCOS-IR. A rat model of PCOS-IR and an adipocyte IR model were generated to investigate the role of quercitrin in regulating reproductive endocrine and lipid metabolism processes in PCOS-IR. RESULTS: Peptidase M20 domain containing 1 (PM20D1) was screened using bioinformatics to evaluate its participation in PCOS-IR. PCOS-IR regulation via the PI3K/Akt signaling pathway was also investigated. Experimental analysis showed that PM20D1 levels were reduced in insulin-resistant 3T3-L1 cells and a letrozole PCOS-IR rat model. Reproductive function was inhibited, and endocrine metabolism was abnormal. The loss of adipocyte PM20D1 aggravated IR. In addition, PM20D1 and PI3K interacted with each other in the PCOS-IR model. Furthermore, the PI3K/Akt signaling pathway was shown to participate in lipid metabolism disorders and PCOS-IR regulation. Quercitrin reversed these reproductive and metabolic disorders. CONCLUSION: PM20D1 and PI3K/Akt were required for lipolysis and endocrine regulation in PCOS-IR to restore ovarian function and maintain normal endocrine metabolism. By upregulating the expression of PM20D1, quercitrin activated the PI3K/Akt signaling pathway, improved adipocyte catabolism, corrected reproductive and metabolic abnormalities, and had a therapeutic effect on PCOS-IR.

DRm217 attenuates myocardial ischemia-reperfusion injury via stabilizing plasma membrane Na+-K+-ATPase, inhibiting Na+-K+-ATPase/ROS pathway and activating PI3K/Akt and ERK1/2.

Na+-K+-ATPase has close relationship with myocardial ischemia/reperfusion (IR) injury. Activation of Na+-K+-ATPase with its DR region specific antibody produces cardioprotective effect. In this study, we aimed to explore whether DRm217, a proved DR region specific antibody, could protect myocardial cells against IR injury and uncover the mechanisms under it. By employing H9c2 myocardial cell and SD rat, we found that DRm217 protected cardiac cells against IR-induced cell injury and apoptosis. DRm217 produced protective effect via stabilizing Na+-K+-ATPase membrane expression and inhibiting Na+-K+-ATPase/Src/NADPH oxidase dependent ROS accumulation. PI3K/Akt and ERK1/2 participated in DRm217-induced cardiomyocyte survival, but not in DRm217-related ROS reduction. Therefore, DRm217 can be used as a potential cardioprotective adjuvant in myocardial IR therapy and interference of Na+-K+-ATPase/ROS pathway will be a promising modality for clinical myocardial IR therapy.