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Cardiac remodeling is the major pathological change of heart failure. And let-7 family has been implicated in the development and pathogenesis of cardiovascular diseases. However, the mechanisms underlying let-7b-5p-mediated cellular pathogenesis of cardiac remodeling are not well understood. The present study aimed to explore the effects of let-7b-5p on cardiac remodeling and the corresponding regulatory mechanism. In vivo results indicated that cardiac let-7b-5p was upregulated in the mouse model of Angiotensin II (Ang II)-induced cardiac remodeling. Additionally, let-7b-5p knockdown ameliorated the effects of Ang II-induced cardiac remodeling, whereas let-7b-5p overexpression facilitated cardiac remodeling. In vitro, let-7b-5p mimics induced cardiomyocyte hypertrophy, fibroblast transdifferentiation, and the expression of inflammatory factors in neonatal mouse cardiomyocytes (NMCMs), neonatal mouse cardiac fibroblasts (NMCFs), and bone marrow-derived macrophages (BMDMs), respectively. Furthermore, let-7b-5p exerted its cardiac pro-remodeling effects at least partially through a small extracellular vesicle (SEV)-based delivery strategy. We found that let-7b-5p was enriched in SEVs derived from Ang II-treated NMCMs (NMCM-SEV) but not from Ang II-treated NMCFs (NMCF-SEV). Mechanistic analyses revealed that NMCM-SEV promoted TLR7 and MyD88 expression, which increased NF-κB phosphorylation levels. Knockdown of let-7b-5p, TLR7 or MyD88 in NMCMs, NMCFs, and BMDMs abolished the cardiac pro-remodeling effects of NMCM-SEV. These results uncover that let-7b-5p-containing NMCM-SEVs promote cardiac remodeling via the TLR7/MyD88/NF-κB pathway, implicating let-7b-5p as a potential therapeutic target for heart failure., (© 2024 Federation of American Societies for Experimental Biology.)

Background: A grim prognosis of pancreatic cancer (PCa) was attributed to the difficulty in early diagnosis of the disease., Aims: Identifying novel biomarkers for early detection of PCa is thus urgent to improve the overall survival rates of patients., Methods: The study was performed firstly by identification of candidate microRNAs (miRNAs) in formalin-fixed, paraffin-embedded tissues using microarray profiles, and followed by validation in a serum-based cohort study to assess clinical utility of the candidates. In the cohorts, a total of 1273 participants from four centers were retrospectively recruited as two cohorts including training and validation cohort. The collected serum specimens were analyzed by real-time polymerase chain reaction., Results: We identified 27 miRNAs expressed differentially in PCa tissues as compared to the benign. Of which, the top-four was selected as a panel whose diagnostic efficacy was fully assessed in the serum specimens. The panel exhibited superior to CA19-9, CA125, CEA and CA242 in discriminating patients with early stage PCa from healthy controls or non-PCa including chronic pancreatitis as well as pancreatic cystic neoplasms, with the area under the curves (AUC) of 0.971 (95% CI 0.956-0.987) and 0.924 (95% CI 0.899-0.949), respectively. Moreover, the panel eliminated interference from other digestive tumors with a specificity of 90.2%., Conclusions: A panel of four serum miRNAs was developed showing remarkably discriminative ability of early stage PCa from either healthy controls or other pancreatic diseases, suggesting it may be developed as a novel, noninvasive approach for early screening of PCa in clinic., (© 2024. The Author(s).)

In previous chapters, we know that high-density lipoproteins (HDLs) could act at multiple cell lines and then trigger intracellular molecular pathway to prevent several metabolic diseases. Besides the classic genes regulating cholesterol efflux and reverse cholesterol transport (RCT), microRNAs (miRNAs) could also affect HDLs biogenesis, metabolism, and functions. This chapter summarizes the miRNAs, which regulate HDLs functions in table. In addition, HDLs are good vectors for miRNAs. They could carry miRNAs in circulation and take them into several cells such as macrophages and endothelial cells. Complete understanding of the miRNAs associated with HDL regulation would give us broader insights to prevent and treat metabolic diseases., (© 2022. Springer Nature Singapore Pte Ltd.)