LncRNA DLEU1 contributes to the progression of septic myocardial dysfunction by targeting miR-381-3p

Abstract

Introduction: Cardiac dysfunction is a common complication of sepsis. This study aimed to elucidate the regulatory effect of DLEU1 on sepsis-induced myocardial injury.

Material and methods: HL-1 cardiomyocytes were treated with lipopolysaccharide (LPS) to mimic sepsis-induced myocardial injury in vitro, and the mouse septic model was established through cecum ligation and perforation (CLP). Cell viability was evaluated using Cell Counting Kit-8 (CCK-8), while apoptosis was assessed via Annexin-V staining. Pro-inflammatory factors including tumor necrosis factor α (TNF-α), interleukin (IL)-1 β, IL-6, and oxidative stress indicators were detected by ELISA kits. Cardiac function in mice was determined using cardiac ultrasound, and myocardial indices were detected by ELISA.

Results: DLEU1 levels were up-regulated gradually in HL-1 cardiomyocytes after LPS treatment in a dose-dependent manner, along with the overactivation of inflammatory responses and oxidative stress. DLEU1 downregulation alleviated LPS-induced cell apoptosis, inflammatory response and oxidative stress. In vivo, DLEU1 knockdown improved the cardiac function of septic mice, and alleviated inflammation and oxidative stress. MiR-381-3p, acting as a competing endogenous RNA (ceRNA) of DLEU1, reversed the effects of DLEU1 in both septic cell and mouse models.

Conclusions: The results indicate that the DLEU1/miR-381-3p axis is an intrinsic regulator of myocardial injury in sepsis.

Keywords: DLEU1; inflammation; miR-381-3p; myocardial injury; sepsis.

Fig. 1

Expression of DLEU1 induced by LPS. A) The DLEU1 content increased with the increase in dose of LPS. B) DLEU1 expression increased with the increase in time of LPS treatment. *p < 0.05, **p < 0.01, ***p < 0.001

Fig. 2

Role of DLEU1 on HL-1 cells. A) DLEU1 expression levels were upregulated in the LPS group and partially downregulated in LPS + sh-DLEU1. B, C) Downregulation of DLEU1 reversed the LPS-induced elevation of apoptosis and reduction in viability. D-G) Inflammatory factors and oxidative stress indicators are regulated by DLEU1. ***p < 0.001, compared to the blank group; ###p < 0.001, compared to the LPS group

Fig. 3

Role of DLEU1 in myocardial injury. A) sh-DLEU1 successfully inhibited its expression in mice. B-D) LVSP, LVEDP, and ± dp/dtmax were regulated by DLEU1. ***p < 0.001, compared to the sham group; ###p < 0.001, compared to the CLP group

Fig. 4

A, B) sh-DLEU1 suppressed the CK-MB and cTnI levels steered by CLP. C) The inflammatory factors were influenced by DLEU1. D-F) The oxidative situation was affected by DLEU1. ***p < 0.001, compared to the sham group; ###p < 0.001, compared to the CLP group

Fig. 5

CeRNA of DLEU1. A) Putative targeting sequences. B) Identification of the targeting relationship between DLEU1 and miR-381-3p. C) Silencing of DLEU1 changed the levels of miR-381-3p. ***p < 0.001, compared to the NC group or blank group; ###p < 0.001, compared to the LPS group

Fig. 6

miR-381-3p was involved in DLEU1 regulation of cardiomyocytes. A) Co-transfection reduced miR-381-3p expression. B-G) Apoptosis, viability, inflammation level, and oxidative stress are regulated by miR-381-3p expression. **p < 0.01, ***p < 0.001

Fig. 7

Regulation of miR-381-3p in a mouse model. A, B) Effects of sh-DLEU1, sh-DLEU1, and miR-381-3p inhibitor on miR-381-3p expression levels in mouse models. C-E) The alteration of miR-381-3p levels changed the LVSP, LVEDP, and ± dp/dtmax levels. **p < 0.01, ***p < 0.001, compared to the sham group or CLP + sh-DLEU1 group; ###p < 0.001, compared to the CLP group

Fig. 8

miR-381-3p affected myocardial indices, inflammatory factors, and oxidative stress in a mouse model. A, B) Down-regulation of miR-381-3p altered the effects of DLEU1 on cellular damage. C-F) The inflammatory factors and oxidative situation were mediated by miR-381-3p. ***p < 0.001