Chemotactic NO/H2S Nanomotors Realizing Cardiac Targeting of G-CSF against Myocardial Ischemia-Reperfusion Injury.

Recombinant granulocyte colony-stimulating factor (G-CSF), with a direct repair effect on injured cardiomyocytes against myocardial infarction ischemia-reperfusion-injury (IRI), displays a poor effect owing to the limited cardiac targeting efficacy. There are almost no reports of nanomaterials that deliver G-CSF to the IRI site. Herein, we propose a way to protect G-CSF by constructing one layer of nitric oxide (NO)/hydrogen sulfide (H2S) nanomotors on its outside. NO/H2S nanomotors with specific chemotactic ability to high expression of reactive oxygen species (ROS)/induced nitric oxide synthase (iNOS) at the IRI site can deliver G-CSF to the IRI site efficiently. Meanwhile, superoxide dismutase is covalently bound to the outermost part, reducing ROS at the IRI site through a cascade effect with NO/H2S nanomotors. The synergistic effect between NO and H2S on the effective regulation of the IRI microenvironment can not only avoid toxicity caused by excessive concentration of a single gas but also reduce inflammation level and relieve calcium overload, so as to promote G-CSF to play a cardioprotective role.

Optimization of Strategy for Modified mRNA Inducing Cardiac-Specific Expression in Mice.

Lipid nanoparticle (LNP)-coated-modified RNA(modRNA) has been developed for enhancing the stability of modRNA, but it tends to accumulate in liver. The current study aimed to optimize strategy for increasing cardiac expression efficiency of modRNA. We synthesized Luciferase (Luc)-modRNA, and also developed 122Luc modRNA, a liver silencing Luc modRNA. Intramyocardial injection of naked Luc modRNA induced high bioluminescence signal in heart, but very low in other organs including liver. Luc modRNA-LNP injection showed the signal was increased by 5 folds in the heart and by 15,000 folds in the liver, compared to naked Luc modRNA group. In comparison with Luc modRNA-LNP group, the liver signal was decreased to 0.17%, while cardiac signal showed a slight drop by intramyocardial injection of 122Luc-modRNA-LNP. Our data revealed that intramyocardial injection of naked modRNA could effectively induced cardiac-specific expression. For cardiac delivery of Luc modRNA-LNP, 122modRNA-LNP enhances specificity of cardiac expression by abolishing liver signal.

Elevated Wnt2 and Wnt4 activate NF-κB signaling to promote cardiac fibrosis by cooperation of Fzd4/2 and LRP6 following myocardial infarction.

BACKGROUND: Acute myocardial infarction (AMI)-induced excessive myocardial fibrosis exaggerates cardiac dysfunction. However, serum Wnt2 or Wnt4 level in AMI patients, and the roles in cardiac fibrosis are largely unkown. METHODS: AMI and non-AMI patients were enrolled to examine serum Wnt2 and Wnt4 levels by ELISA analysis. The AMI patients were followed-up for one year. MI mouse model was built by ligation of left anterior descending branch (LAD). FINDINGS: Serum Wnt2 or Wnt4 level was increased in patients with AMI, and the elevated Wnt2 and Wnt4 were correlated to adverse outcome of these patients. Knockdown of Wnt2 and Wnt4 significantly attenuated myocardial remodeling and cardiac dysfunction following experimental MI. In vitro, hypoxia enhanced the secretion and expression of Wnt2 and Wnt4 in neonatal rat cardiac myocytes (NRCMs) or fibroblasts (NRCFs). Mechanistically, the elevated Wnt2 or Wnt4 activated ß-catenin /NF-κB signaling to promote pro-fibrotic effects in cultured NRCFs. In addition, Wnt2 or Wnt4 upregulated the expression of these Wnt co-receptors, frizzled (Fzd) 2, Fzd4 and (low-density lipoprotein receptor-related protein 6 (LRP6). Further analysis revealed that Wnt2 or Wnt4 activated ß-catenin /NF-κB by the co-operation of Fzd4 or Fzd2 and LRP6 signaling, respectively. INTERPRETATION: Elevated Wnt2 and Wnt4 activate ß-catenin/NF-κB signaling to promote cardiac fibrosis by cooperation of Fzd4/2 and LRP6 in fibroblasts, which contributes to adverse outcome of patients with AMI, suggesting that systemic inhibition of Wnt2 and Wnt4 may improve cardiac dysfunction after MI.

Cardiac Wnt5a and Wnt11 promote fibrosis by the crosstalk of FZD5 and EGFR signaling under pressure overload.

Progressive cardiac fibrosis accelerates the development of heart failure. Here, we aimed to explore serum Wnt5a and Wnt11 levels in hypertension patients, the roles of Wnt5a and Wnt11 in cardiac fibrosis and potential mechanisms under pressure overload. The pressure overload mouse model was built by transverse aortic constriction (TAC). Cardiac fibrosis was analyzed by Masson's staining. Serum Wnt5a or Wnt11 was elevated and associated with diastolic dysfunction in hypertension patients. TAC enhanced the expression and secretion of Wnt5a or Wnt11 from cardiomyocytes (CMs), cardiac fibroblasts (CFs), and cardiac microvascular endothelial cells (CMECs). Knockdown of Wnt5a and Wnt11 greatly improved cardiac fibrosis and function at 4 weeks after TAC. In vitro, shWnt5a or shWnt11 lentivirus transfection inhibited pro-fibrotic effects in CFs under mechanical stretch (MS). Similarly, conditional medium from stretched-CMs transfected with shWnt5a or shWnt11 lentivirus significantly suppressed the pro-fibrotic effects induced by conditional medium from stretched-CMs. These data suggested that CMs- or CFs-derived Wnt5a or Wnt11 showed a pro-fibrotic effect under pressure overload. In vitro, exogenous Wnt5a or Wnt11 activated ERK and p38 (fibrotic-related signaling) pathway, promoted the phosphorylation of EGFR, and increased the expression of Frizzled 5 (FZD5) in CFs. Inhibition or knockdown of EGFR greatly attenuated the increased FZD5, p-p38, and p-ERK levels, and the pro-fibrotic effect induced by Wnt5a or Wnt11 in CFs. Si-FZD5 transfection suppressed the increased p-EGFR level, and the fibrotic-related effects in CFs treated with Wnt5a or Wnt11. In conclusion, pressure overload enhances the secretion of Wnt5a or Wnt11 from CMs and CFs which promotes cardiac fibrosis by activation the crosstalk of FZD5 and EGFR. Thus, Wnt5a or Wnt11 may be a novel therapeutic target for the prevention of cardiac fibrosis under pressure overload.

Triple-localized WHIRLY2 Influences Leaf Senescence and Silique Development via Carbon Allocation.

Coordination of gene expression in mitochondria, plastids, and nucleus is critical for plant development and survival. Although WHIRLY2 (WHY2) is involved in mitochondrial genome repair and affects the DNA copy number of the mitochondrial genome, the detailed mechanism of action of the WHY2 protein is still elusive. In this study, we found that WHY2 was triple-localized among the mitochondria, plastids, and the nucleus during Arabidopsis (Arabidopsis thaliana) aging. Overexpressing WHY2 increased starch granule numbers in chloroplasts of pericarp cells, showing a partially dry, yellowing silique and early senescence leaves. Accordingly, WHY2 protein could directly activate the expression of jasmonic acid carboxyl methyltransferase and senescence associated gene 29 (SWEET15) gene expression and repress SWEET11 gene expression in the nucleus, leading to alteration of starch accumulation and transport in pericarp cells. In contrast, loss of WHY2 decreased starch and sugar content in pericarp cells but promoted starch accumulation in leaves and seeds. These phenotypes of WHY2-overexpressing plants were enhanced in response to methyl jasmonate. Our results suggest that WHY2 in plastids, mitochondria, and the nucleus plays a vital role in alteration of carbon reallocation from maternal tissue to filial tissue.