miR-331 inhibits CLDN2 expression and may alleviate the vascular endothelial injury induced by sepsis

Claudin-2 upregulation enhances intestinal permeability, immune activation, dysbiosis, and mortality in sepsis

Intestinal epithelial expression of the tight junction protein claudin-2, which forms paracellular cation and water channels, is precisely regulated during development and in disease. Here, we show that small intestinal epithelial claudin-2 expression is selectively upregulated in septic patients. Similar changes occurred in septic mice, where claudin-2 upregulation coincided with increased flux across the paracellular pore pathway. In order to define the significance of these changes, sepsis was induced in claudin-2 knockout (KO) and wild-type (WT) mice. Sepsis-induced increases in pore pathway permeability were prevented by claudin-2 KO. Moreover, claudin-2 deletion reduced interleukin-17 production and T cell activation and limited intestinal damage. These effects were associated with reduced numbers of neutrophils, macrophages, dendritic cells, and bacteria within the peritoneal fluid of septic claudin-2 KO mice. Most strikingly, claudin-2 deletion dramatically enhanced survival in sepsis. Finally, the microbial changes induced by sepsis were less pathogenic in claudin-2 KO mice as survival of healthy WT mice injected with cecal slurry collected from WT mice 24 h after sepsis was far worse than that of healthy WT mice injected with cecal slurry collected from claudin-2 KO mice 24 h after sepsis. Claudin-2 upregulation and increased pore pathway permeability are, therefore, key intermediates that contribute to development of dysbiosis, intestinal damage, inflammation, ineffective pathogen control, and increased mortality in sepsis. The striking impact of claudin-2 deletion on progression of the lethal cascade activated during sepsis suggests that claudin-2 may be an attractive therapeutic target in septic patients.

MiR-107-3p Knockdown Alleviates Endothelial Injury in Sepsis via Kallikrein-Related Peptidase 5

INTRODUCTION

Endothelial injury is a major characteristic of sepsis and contributes to sepsis-induced multiple-organ dysfunction. In this study, we investigated the role of miR-107-3p in sepsis-induced endothelial injury.

METHODS

Human umbilical vein endothelial cells (HUVECs) were exposed to 20 μg/mL of lipopolysaccharide (LPS) for 6-48 h. The levels of miR-107-3p and kallikrein-related peptidase 5 (KLK5) were examined. HUVECs were treated with LPS for 12 h and subsequently transfected with miR-107-3p inhibitor, KLK5 siRNA, or cotransfected with KLK5 siRNA and miR-107-3p inhibitor/negative control inhibitor. Cell survival, apoptosis, invasion, cell permeability, inflammatory response, and the Toll-like receptor 4/nuclear factor κB signaling were evaluated. In addition, the relationship between miR-107-3p and KLK5 expression was predicted and verified.

RESULTS

LPS significantly elevated miR-107-3p levels, which peaked at 12 h. Conversely, the KLK5 level was lower in the LPS group than in the control group and was lowest at 12 h. MiR-107-3p knockdown significantly attenuated reductions in cell survival and invasion, apoptosis promotion, hyperpermeability and inflammation induction, and activation of the NF-κB signaling caused by LPS. KLK5 knockdown had the opposite effect. Additionally, KLK5 was demonstrated as a target of miR-107-3p. MiR-107-3p knockdown partially reversed the effects of KLK5 depletion in LPS-activated HUVECs.

CONCLUSIONS

Our findings indicate that miR-107-3p knockdown may protect against sepsis-induced endothelial cell injury by targeting KLK5. This study identified a novel therapeutic target for sepsis-induced endothelial injury.

NLRP3 inflammasome involves in the pathophysiology of sepsis-induced myocardial dysfunction by multiple mechanisms

Sepsis-induced myocardial dysfunction (SIMD) is one of the serious health-affecting problems worldwide. At present, the mechanisms of SIMD are still not clearly elucidated. The NOD-like receptor protein 3 (NLRP3) inflammasome has been assumed to be involved in the pathophysiology of SIMD by regulating multiple biological processes. NLRP3 inflammasome and its related signaling pathways might affect the regulation of inflammation, autophagy, apoptosis, and pyroptosis in SIMD. A few molecular specific inhibitors of NLRP3 inflammasome (e.g., Melatonin, Ulinastatin, Irisin, Nifuroxazide, and Ginsenoside Rg1, etc.) have been developed, which showed a promising anti-inflammatory effect in a cellular or animal model of SIMD. These experimental findings indicated that NLRP3 inflammasome could be a promising therapeutic target for SIMD treatment. However, the clinical translation of NLRP3 inhibitors for treating SIMD still requires robust in vivo and preclinical trials.

LncRNA UCA1 Accelerates the Progression of Ulcerative Colitis via Mediating the miR-331-3p/BRD4 Axis

Background

Ulcerative colitis (UC) has become one of the fastest-growing severe diseases worldwide with high morbidity. This research aimed to explore the function of lncRNA UCA1 in UC progression.

Methods

RT-qPCR analysis was used to examine the expression of UCA1 level in colonic mucosa tissues of UC patients. Then, fetal human cells (FHCs) were stimulated by LPS to induce inflammatory injury. CCK-8, flow cytometry and ELISA were adopted to determine the influence of UCA1 depletion on cell viability, apoptosis and pro-inflammatory factors levels in LPS-induced FHCs. The interaction between UCA1 and miR-331-3p or BRD4 was confirmed by luciferase reporter assay. The expressions of key factors involved in NF-κB pathway were assessed by Western blotting.

Results

LncRNA UCA1 level was elevated in colonic mucosa tissues of UC patients. LPS stimulation restrained cell viability and promoted the apoptosis and inflammatory factors levels, thus inducing FHCs inflammatory injury, while these effects were partially abolished by UCA1 knockdown. Moreover, it was found that UCA1 silence improved LPS-triggered cell injury via miR-331-3p. In addition, BRD4 was directly targeted by miR-331-3p, and BRD4 deficiency neutralized the effects of miR-331-3p repression on LPS-triggered injury in LPS-treated FHCs.

Conclusion

Our data determined that UCA1 knockdown attenuated UC development via targeting the miR-331-3p/BRD4/NF-κB pathway.

LncRNA NKILA knockdown promotes cell viability and represses cell apoptosis, autophagy and inflammation in lipopolysaccharide-induced sepsis model by regulating miR-140-5p/CLDN2 axis

BACKGROUND

Long non-coding RNAs (lncRNAs) play vital roles in human diseases, including sepsis-induced acute kidney injury (AKI). Here, we aimed to investigate the functions of lncRNA NKILA in sepsis-engendered AKI.

METHODS

HK2 cells stimulated with LPS were used to mimic sepsis-induced AKI in vitro. qRT-PCR was conducted for lncRNA NKILA and miR-140-5p levels. Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis were employed to analyze cell viability and apoptosis. Western blot assay was utilized to measured protein levels. ELISA kits were used to examine the concentrations of IL-6, IL-1β and TNF-α. Dual-luciferase reporter assay was utilized to analyze the relationships among lncRNA NKILA, miR-140-5p and claudin 2 (CLDN2).

RESULTS

LPS restrained HK2 cell viability and accelerated cell apoptosis and autophagy. LncRNA NKILA was increased in LPS-treated HK2 cells. LncRNA NKILA silencing reversed the promotional influence of LPS on cell progression in HK2 cells. miR-140-5p inhibition ameliorated lncRNA NKILA knockdown-mediated cell injury in LPS-mediated HK2 cells. CLDN2 was the target of miR-140-5p. MiR-140-5p elevation promoted cell viability and suppressed cell apoptosis, autophagy and inflammation in LPS-induced HK2 cells, with CLDN2 elevation overturned the effects.

CONCLUSION

LncRNA NKILA silencing protected HK2 cells from LPS-induced impairments by reducing CLDN2 through sponging miR-140-5p.