Performance declination of nanofiltration (NF) membranes
caused by concentration polarization (CP) and membrane fouling has
severely restricted their practical application in many fields. This
work reports the construction of a novel interlayer between the substrate
and the selective layer of conventional composite membranes by coordinating
regulation of carbon quantum dots (CQDs) and polydopamine (PDA). Unlike
traditional methods that treat CP and fouling separately, the new
strategy grants the membrane with dual functions at one time. First,
the insertion of the PDA–CQDs layer reformulates the interfacial
polymerization process that reduces the solute transport resistance
and mitigates the CP issue. Second, the sandwiched photoactive CQDs
can degrade organic molecules adsorbed on the membrane surface under
visible light, which is promising for low-cost fouling remediation.
This study may offer valuable insights into the preparation of durable
self-cleaning NF membranes for the effective treatment of complex
wastewater in various industries.
Background
Cardiac hypertrophy and heart failure are characterized by increased late sodium current and abnormal Ca2+ handling. Ranolazine, a selective inhibitor of the late sodium current, can reduce sodium accumulation and Ca
2+ overload. In this study, we investigated the effects of ranolazine on pressure overload‐induced cardiac hypertrophy and heart failure in mice.
Methods and Results
Inhibition of late sodium current with the selective inhibitor ranolazine suppressed cardiac hypertrophy and fibrosis and improved heart function assessed by echocardiography, hemodynamics, and histological analysis in mice exposed to chronic pressure overload induced by transverse aortic constriction (TAC). Ca2+ imaging of ventricular myocytes from TAC mice revealed both abnormal SR Ca
2+ release and increased SR Ca
2+ leak. Ranolazine restored aberrant SR Ca
2+ handling induced by pressure overload. Ranolazine also suppressed Na
+ overload induced in the failing heart, and restored Na
+‐induced Ca
2+ overload in an sodium‐calcium exchanger (NCX)‐dependent manner. Ranolazine suppressed the Ca
2+‐dependent calmodulin (CaM)/CaMKII/myocyte enhancer factor‐2 (MEF2) and CaM/CaMKII/calcineurin/nuclear factor of activated T‐cells (NFAT) hypertrophy signaling pathways triggered by pressure overload. Pressure overload also prolonged endoplasmic reticulum (ER) stress leading to ER‐initiated apoptosis, while inhibition of late sodium current or NCX relieved ER stress and ER‐initiated cardiomyocyte apoptosis.
Conclusions
Our study demonstrates that inhibition of late sodium current with ranolazine improves pressure overload‐induced cardiac hypertrophy and systolic and diastolic function by restoring Na+ and Ca
2+ handling, inhibiting the downstream hypertrophic pathways and ER stress. Inhibition of late sodium current may provide a new treatment strategy for cardiac hypertrophy and heart failure.
Background: Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acids (AA) to form epoxyeicosatrienoic acids (EETs), which exert beneficial roles in the treatment of cardiovascular diseases, but little is known about its role on adventitial remodeling. Methods: We used C57BL/6J mice in vivo and primary rat adventitial fibroblasts (AFs) in vitro treated with Angiotensin II to investigate the effects of CYP2J2 gene delivery and exogenous EETs administration on adventitial remodeling. Results: CYP/sEH system was found to exist in human adventitia, and involved in adventitial remodeling process. Exogenous EETs administration significantly inhibited Ang II-induced AFs activation, characterized by differentiation, proliferation, migration, and collagen synthesis. These protective effects were partially reversed by PPARγ antagonist GW9662 pretreatment or SOCS3 siRNA transfection. EETs suppressed Ang II-induced IκBα phosphorylation, subsequent NF-κB nuclear translocation via PPARγ dependent signaling pathway in AFs. Additionally, EETs reduced Ang II-induced JAK2, STAT3 phosphorylation and subsequent phosphor-STAT3 nuclear translocation, which were mediated by SOCS3 induction but independent of PPARγ activation. Furthermore, rAAV-CYP2J2 gene delivery reduced vessel wall thickening, AFs differentiation, proliferation and collagen deposition in aortic adventitia induced by Ang II infusion, which were mediated by NF-κB and SOCS3/JAK/STAT signaling pathways in blood pressure dependent and independent manner, respectively. Conclusion: We concluded that CYP2J2 overexpression attenuated Ang II-induced adventitial remodeling via PPARγ-dependent NF-κB and PPARγ-independent SOCS3/JAK/STAT inflammatory signaling pathways.
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