Background/Aims: Epigallocatechin gallate (EGCG) has established protective actions against myocardial ischemia/reperfusion (I/R) injury by regulating autophagy. However, little is known about the mechanisms of EGCG in posttranscriptional regulation in the process of cardioprotection. Here we studied whether microRNAs play a role in EGCG-induced cardioprotection. Methods: The myocardial I/R injury in vitro and in vivo model were made, with or without EGCG pretreatment. The upregulation and silencing of microRNA-384-5p (miR-384) and Beclin-1 in H9c2 cell lines were established. Rats were transfected with miR-384 specific shRNA. Dual-luciferase reporter gene assay was conducted to verify the relationship between miR-384 and Beclin-1. TTC staining was performed to analyze the area of myocardial infarct size. Cell viability was monitored by cell counting kit-8 (CCK-8). The release of cardiac troponin-I (cTnI) was examined by ELISA. The levels of autophagy-related genes or proteins expression were evaluated by qRT-PCR or Western blotting. Autophagosomes of myocardial cells were detected by transmission electron microscopy and laser scanning confocal microscope. Results: I/R increased both autophagosomes and autolysosomes, thereby increasing autophagic flux both in vitro and in vivo. Pretreatment with EGCG attenuated I/R-induced autophagic flux expression, accompanied by an increase in cell viability and a decrease in the size of myocardial infarction. MiR-384 expression was down-regulated in H9c2 cell lines when subjected to I/R, while this suppression could be reversed by EGCG pretreatment. The dual-luciferase assay verified that Beclin-1 was a target of miR-384. Both overexpression of miR-384 and knocking down of Beclin-1 significantly inhibited I/R-induced autophagy, accompanied by the activation of PI3K/Akt pathway, thus enhanced the protective effect of EGCG. However, these functions were abrogated by the PI3K inhibitor, LY294002. Conclusion: We confirmed that EGCG has a protective role in microRNA-384-mediated autophagy by targeting Beclin-1 via activating the PI3K/Akt signaling pathway. Our results unveiled a novel role of EGCG in myocardial protection, involving posttranscriptional regulation with miRNA-384.

Serum amyloid A1 (SAA1) is an acute phase protein produced mainly by the liver to participate in immunomodulation in both sterile and non-sterile inflammation. However, non-hepatic tissues can also synthesize SAA1. It remains to be determined whether SAA1 synthesized locally in the placenta participates in parturition via eliciting inflammatory reactions. In this study, we investigated this issue by using human placenta and a mouse model. We found that SAA1 mRNA and protein were present in human placental villous trophoblasts, which was increased upon syncytialization as well as treatments with lipopolysaccharides (LPS), tumor necrosis factor-α (TNF-α), and cortisol. Moreover, significant increases in SAA1 abundance were observed in the placental tissue or in the maternal blood in spontaneous deliveries without infection at term and in preterm birth with histological chorioamnionitis. Serum amyloid A1 treatment significantly increased parturition-pertinent inflammatory gene expression including interleukin-1β (IL-1β), IL-8, TNF-α, and cyclooxygenase-2 (COX-2), along with increased PGF2α production in syncytiotrophoblasts. Mouse study showed that SAA1 was present in the placental junctional zone and yolk sac membrane, which was increased following intraperitoneal administration of LPS. Intraperitoneal injection of SAA1 not only induced preterm birth but also increased the abundance of IL-1β, TNF-α, and COX-2 in the mouse placenta. Conclusively, SAA1 can be synthesized in the human placenta, which is increased upon trophoblast syncytialization. Parturition is accompanied with increased SAA1 abundance in the placenta. Serum amyloid A1 may participate in parturition in the presence and absence of infection by inducing the expression of inflammatory genes in the placenta.

Background: Ischemia-derived exosomes can restrict excessive autophagy by transferring microRNA-30a (miR30a) to cells. Reports have confirmed that epigallocatechin gallate (EGCG) alleviates acute myocardial infarction (AMI) by regulating autophagy; however, research evaluating the communication with cardiomyocytes and exosomes is lacking. This study aimed to explore whether exosomes derived from EGCGtreated cardiomyocytes mitigated AMI by adjusting miR30a to inactivate apoptosis and autophagy. Methods: Exosomes were extracted from cardiomyocytes, cultured either in control or AMI condition, with or without EGCG pretreatment. The exosome characteristics were analyzed by nanoparticle tracking analyses and transmission electron microscopy. The change in miR30a in cells and exosomes was demonstrated by qRT-PCR. H9c2 or stable miR30a knockdown (miR30a KD) cell lines were incubated with exosomes derived from EGCG-treated cardiomyocytes in vitro or in vivo. The effect of EGCG and exosomes on I/ R-induced cardiomyocyte apoptosis and autophagy was assessed. Results: EGCG improved the activity of cardiomyocytes, and increased average diameter, concentration, miR30a mRNA level, and specific protein expression in AMIderived exosomes produced by cardiomyocytes. Moreover, the coincubation of AMI cells with EGCG or exosomes derived from EGCG-treated cardiomyocytes attenuated cardiomyocyte apoptosis and autophagy. Conclusions: The findings showed that EGCG upregulates miR30a, which was efficiently transferred via exosomes between cardiomyocytes, thereby contributing to the suppression of apoptosis and autophagy. By focusing on the cardiomyocyte microenvironment, we identified a new target of EGCG alleviating AMI by regulating apoptosis and autophagy.

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