Search

Background: As a pattern recognition receptor, Toll‐like receptor 7 (TLR7) widely presented in the endosomal membrane of various cells. However, the precise role and mechanism of TLR7 in septic cardiomyopathy remain unknown. This study aims to determine the role of TLR7 in cardiac dysfunction during sepsis and explore the mechanism of TLR7 in septic cardiomyopathy. Methods: We generated a mouse model of septic cardiomyopathy by challenging with lipopolysaccharide (LPS). TLR7‐knockout (TLR7−/−), wild‐type (WT) mice, cardiac‐specific TLR7‐transgenic (cTG‐TLR7) overexpression, and littermates WT (LWT) mice were subjected to septic model. Additionally, to verify the role and mechanism of TLR7 in vitro, we transfected neonatal rat ventricular myocytes (NRVMs) with Ad‐TLR7 and TLR7 siRNA before LPS administration. The effects of TLR7 were assessed by Ca2+ imaging, western blotting, immunostaining, and quantitative real‐time polymerase chain reaction (qPCR). Results: We found that TLR7 knockout markedly exacerbated sepsis‐induced systolic dysfunction. Moreover, cardiomyocytes isolated from TLR7−/− mice displayed weaker Ca2+ handling than that in WT mice in response to LPS. Conversely, TLR7 overexpression alleviated LPS‐induced systolic dysfunction, and loxoribine (TLR7‐specific agonist) improved LPS‐induced cardiac dysfunction. Mechanistically, these optimized effects were associated with enhanced the adenosine (cAMP)‐protein kinase A (PKA) pathway, which upregulated phosphorylate‐phospholamban (p‐PLN) (Ser16) and promoted sarco/endoplasmic reticulum Ca2+ ATPase (Serca) and Ryanodine Receptor 2 (RyR2) expression in the sarcoplasmic reticulum (SR), and ultimately restored Ca2+ handling in response to sepsis. While improved Ca2+ handling was abrogated after H89 (a specific PKA inhibitor) pretreatment in cardiomyocytes isolated from cTG‐TLR7 mice. Consistently, TLR7 overexpression improved LPS‐induced Ca2+‐handling decrement in NRVMs. Nevertheless, TLR7 knockdown showed a deteriorative phenotype. Conclusions: Our data demonstrated that activation of TLR7 protected against sepsis‐induced cardiac dysfunction through promoting cAMP‐PKA‐PLN pathway, and we revealed that TLR7 might be a novel therapeutic target to block the septic cardiomyopathy and support systolic function during sepsis. [ABSTRACT FROM AUTHOR]

Background and Aim: MicroRNAs are a class of small non-coding RNAs that negatively regulate the expression of their target genes. The aim of the present study was to explore the effects of microRNA on biological behaviors of HepG2 cells and further analyze its characteristics. Methods: We detected different expression profiles of miRNAs in HepG2 and L02 cell lines by microRNA microarray. Northern blot, quantitative real-time polymerase chain reaction, methylthiazolyl tetrazolium, fluorescence-activated cell sorting, scratch wound, transwell migration and Matrigel invasion assays and western blot were carried out to determine whether or not microRNA-224 ( miR-224) can influence the biological behaviors of HepG2 cells. Results: MiR-224 was significantly upregulated in HepG2 cells. Cell proliferation, migration and invasion, but not cell cycles, were altered after changing the expression of miR-224. Taking invasion and migration as a breakthrough, a close relationship between the expression of miR-224 and its proteins such as PAK4 and MMP9, which were involved in the invasion of tumor, was found. Conclusions: Overexpression of miR-224 was involved in the malignant phenotype of HepG2 cells, and it may be an important factor in regulating the migration and invasion of HepG2 cells. [ABSTRACT FROM AUTHOR]

Examines the molecular regulation of nectary development. Use of reverse transcriptase-polymerase chain reaction in cloning of NEC1, a gene expressed in the nectaries of Petunia hybrida; Presence of NEC1 protein in the nectaries; Role of NEC1 gene in sugar metabolism and nectar secretion.