CIRC_0001818 TARGETS MIR-136-5P TO INCREASE LIPOPOLYSACCHARIDE-INDUCED HK2 CELL INJURIES BY ACTIVATING TXNIP/NLRP3 INFLAMMASOME PATHWAY.

ABSTRACT: Background: The implication of circular RNAs (circRNAs) in sepsis-related complications arouses much attention, which provides additional treatment options for sepsis-related complications. The purpose of this study is to unveil the function and functional mechanism of circ_0001818 in cell models of septic acute kidney injury (AKI). Methods: Septic AKI cell models were constructed using HK2 cells treated with lipopolysaccharide (LPS). The expression levels of circ_0001818, miR-136-5p, and thioredoxin interacting protein (TXNIP) mRNA were examined by quantitative real-time polymerase chain reaction. Cell viability and death were explored by CCK-8 and flow cytometry assays. The activity of oxidative stress-related markers was examined using commercial kits. The secretion of inflammatory factors was examined using ELISA kits. The binding between miR-136-5p and circ_0001818 or TXNIP was validated by dual-luciferase reporter test and pull-down assay. The receiver operating characteristic curve was depicted to assess the diagnostic value of circ_0001818, miR-136-5p, and TXNIP in serumal exosomes from patients with septic AKI. Results: Circ_0001818 expression was elevated in LPS-treated HK2 cells. Loss-of-function assays displayed that circ_0001818 downregulation alleviated LPS-induced HK2 cell death, oxidative stress, inflammatory release, and inflammasome activation. MiR-136-5p was targeted by circ_0001818, and inhibition of miR-136-5p attenuated the effects of circ_0001818 downregulation, thus recovering LPS-induced HK2 cell injuries. MiR-136-5p targeted the downstream TXNIP, and circ_0001818 dysregulation could affect TXNIP expression via targeting miR-136-5p. Overexpression of TXNIP overturned the effects of circ_0001818 downregulation. Moreover, circ_0001818, miR-136-5p, and TXNIP in serumal exosomes had diagnostic values. Conclusions: Circ_0001818 targets miR-136-5p to activate TXNIP expression, leading to the contribution of LPS-induced HK2 cell injury.

YY1 PROMOTES MICROGLIA M2 POLARIZATION THROUGH THE MIR-130A-3P/TREM-2 AXIS TO ALLEVIATE SEPSIS-ASSOCIATED ENCEPHALOPATHY.

ABSTRACT: Purpose: Sepsis-associated encephalopathy (SAE) induces cognitive dysfunction via mechanisms that commonly involve neuroinflammation. Yin Yang 1 (YY1) is an important transcription factor that acts as a key role in sepsis and neuroepithelium development. However, the function of YY1 in SAE remains unclear. Our study aimed to probe the intrinsic and concrete molecular mechanism of YY1 in SAE. Methods: SAE cell model and SAE animal model were constructed by lipopolysaccharide (LPS) treatment and cecal ligation and puncture surgery, respectively. Behavioral tests were performed to analyze the cognitive function. The polarization state of mouse microglia (BV-2 cells) was assessed by flow cytometry assay. The mRNA and protein expressions were assessed by qRT-PCR and western blot. Finally, the binding relationships between YY1, miR-130a-3p, andTREM-2were verified by dual luciferase reporter gene assay and/or ChIP assay. Results: Here our results described that YY1 and TREM-2 were downregulated and miR-130a-3p was upregulated in SAE. YY1 overexpression could promote M2 polarization of microglia, and alleviate neuroinflammation and behavioral deficits in vitro and in vivo. YY1 could inhibit miR-130a-3p promoter activity. As expected, miR-130a-3p overexpression abolished the effects of YY1 overexpression on LPS-treated BV-2 cells. Besides, TREM-2 was identified as the target of miR-130a-3p. TREM-2 silencing could reverse the effects of miR-130a-3p inhibition on LPS-treated BV-2 cells. Conclusion: Taken together, YY1 promoted microglia M2 polarization via upregulating TREM-2 by interacting with miR-130a-3p promoter, suggesting YY1 overexpression might be a novel therapeutic strategy of SAE.

Relationships between genetic polymorphisms of triggering receptor expressed on myeloid cells-1 and septic shock in a Chinese Han population.

BACKGROUND: Triggering receptor expressed on myeloid cells-1 (TREM-1) is a cell surface receptor expressed on neutrophils and monocytes. TREM-1 acts to amplify inflammation and serves as a critical mediator of inflammatory response in the context of sepsis. To date, the predisposition of TREM-1 gene polymorphisms to septic shock has not been reported. This study was designed to investigate whether TREM-1 genomic variations are associated with the development of septic shock. METHODS: We genotyped two TREM-1 single nucleotide polymorphisms (SNPs, rs2234237 and rs2234246) and evaluated the relationships between these SNPs and septic shock on susceptibility and prognosis. RESULTS: TREM-1 rs2234246 A allele in the promoter region was significantly associated with the susceptibility of septic shock in recessive model (AA, OR=3.10, 95%CI 1.15 to 8.32, P=0.02), and in codominant model (AG, OR=0.72, 95%CI 0.43-1.19, P=0.02; AA, OR=2.71, 95%CI 1.00-7.42; P=0.03). However, in three inherited models (dominant model, recessive model, and codominant model), none of the assayed loci was significantly associated with the prognosis of septic shock. The non-survivor group demonstrated higher plasma IL-6 levels (99.7±34.7 pg/mL vs. 61.2±26.5 pg/mL, P<0.01) than the survivor group. Plasma concentrations of IL-6 among the three genotypes of rs2234246 were AA 99.4±48.9 pg/mL, AG 85.4±43 pg/mL, and GG 65.3±30.7 pg/mL (P<0.01). The plasma concentrations of IL-6 in patients with AA genotypes were significantly higher than those in patients with GG genotypes (P<0.01). CONCLUSION: TREM-1 genetic polymorphisms rs2234246 may be significantly correlated only with susceptibility to septic shock in the Chinese Han population.

Association of serum myeloid cells of soluble triggering receptor-1 level with myocardial dysfunction in patients with severe sepsis.

OBJECTIVE: To investigate the association of serum sTREM-1 with myocardial dysfunction in patients with severe sepsis. METHODS: A total of 85 patients with severe sepsis were divided into severe sepsis group (n = 40) and septic shock group (n = 45). Serum levels of sTREM-1, NT-proBNP, APACHE II score, SOFA score, cardiac index, cardiac function index, global ejection fraction, and left ventricular contractility index were measured on days 1, 3, and 7 after admission to ICU. RESULTS: Serum sTREM-1 levels of patients with septic shock were significantly higher than those with severe sepsis on days 1, 3, and 7. Serum sTREM-1 was positively correlated with APACHE II scores, SOFA scores, and NT-proBNP. However, The sTREM-1 level was markedly negatively correlated with CI, CFI, GEF, and dP/dt max, respectively. Multiple logistic regression analysis showed that sTREM-1 was independent risk factor to NT-proBNP increasing. The optimal cut-off point of sTREM-1 for detecting patients with myocardial dysfunction was 468.05 ng/mL with sensitivity (80.6%) and specificity (75.7%). There is no difference in TREM-1-mRNA expression between the two groups. CONCLUSIONS: Serum sTREM-1 is significantly associated with myocardial dysfunction and may be a valuable tool for determining the presence of myocardial dysfunction in patients with severe sepsis.