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 infl ammation and serves as a critical mediator of infl ammatory 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 signifi cantly 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 signif icantly associated with the prognosis of septic shock. The nonsurvivor 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/m L, AG 85.4±43 pg/m L, and GG 65.3±30.7 pg/m L(P<0.01). The plasma concentrations of IL-6 in patients with AA genotypes were signifi cantly 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.

Relationship between expression of triggering receptor-1 on myeloid cells in intestinal tissue and intestinal barrier dysfunction in severe acute pancreatitis

BACKGROUND：Triggering receptor expressed on myeloid cells-1 （TREM-1） in the intestine was upregulated and correlated with disease activity in inflammatory bowel diseases. Membrane- bound TREM-1 protein is increased in the pancreas, liver and kidneys of patients with severe acute pancreatitis （SAP）, suggesting that TREM-1 may act as an important mediator of inflammation and subsequent extra-pancreatic organ injury. This study aimed to investigate the relationship between the expression of TREM-1 in intestinal tissue and intestinal barrier dysfunction in SAP. METHODS： Sixty-four male Wistar rats were randomly divided into a sham operation group （SO group, n=32） and a SAP group （n=32）. A SAP model was established by retrograde injection of 5% sodium deoxycholate into the bile-pancreatic duct. Specimens were taken from blood and intestinal tissue 2, 6, 12, and 48 hours after operation respectively. The levels of D-lactate, diamine oxidase （DAO） and endotoxin in serum were measured using an improved spectro-photometric method. The expression levels of TREM-1, interleukin-1β （IL-1β）, and tumor necrosis factor-α （TNF-α） mRNA in terminal ileum were detected by real-time reverse transcription-polymerase chain reaction （RT-PCR）. Specimens of the distal ileum were taken to determine pathological changes by a validated histology score. The serum levels of D-lactate, DAO and endotoxin were significantly increased in each subgroup of SAP compared with the SO group （P〈0.01, P〈0.05）. The expression levels of TREM-1, IL-1β and TNF-a mRNA in the terminal ileum in each subgroup of SAP were significantly higher than those in the SO group （P〈0.01, P〈0.05）. The expression level of TREM-lmRNA was positively correlated with IL-1βand TNF-α mRNA （r=0.956, P=0.044; r=0.986, P=0.015）, but the correlation was not found between IL-1β mRNA and TNF-a mRNA （P=0.133）. Compared to the SO group, the pathological changes were aggravated significantly in the SAP group. CONCLUSIONS： The expression level of TREM-1 in intestinal tissue of rats with SAP was elevated, leading to the release of inflammatory mediators and intestinal mucosal injury. This finding indicates that TREM-I might play an important role in the development of intestinal barrier dysfunction in rats with SAP.

TREM-1 expression in rat corneal epithelium with Aspergillus fumigatus infection

AIM: To investigate the expression of triggering receptor expressed on myeloid cells-1(TREM-1) in the aberrant inflammation within the corneal epithelium at early period of fungal infection.METHODS: A total of 65 Wistar rats were randomly divided into control group, sham group and fungal keratitis(FK) group, in which the cornea was infected by Aspergillus fumigatus(A. fumigatus). After executed randomly at 8, 16, 24, 48 and 72 h after experimental model being established, the severity of keratomycosis in rats was scored visually with the aid of a dissecting microscope and slit lamp. Then corneas in three groups were collected to assess the expression of TREM-1through quantitative reverse transcription-polymerase chain reaction(RT-PCR), immunofluorescence technique and Western blot analysis. The correlation between FK inflammation and expression of TREM-1 was also analyzed.RESULTS: Corneal inflammation scores increased with time after fungal infection(F =49.74, P =0.000). The inflammation scores in FK group were obviously higher than those in sham group on the whole(F =137.78, P =0.000). Levels of TREM-1 in the infected rat corneal epithelium had elevated at 8h and peaked at 48h(P 【0.001,compared with control group). Western blot analysis also showed an obviously elevated TREM-1 level in rat corneal epithelium at 24 h and 48 h after fungal infection.Immunofluorescence technique showed that TREM-1mainly existed in corneal epithelium and infected corneal stoma of rat. TREM-1 protein expression was enhanced after fungal infection. Moreover, severity of FK inflammation was significantly related to TREM-1expression in FK(r =0.942, P =0.000).CONCLUSION: TREM-1 may contribute to amplify theinflammation in the cornea infected with A. fumigatus and play critical roles in the battle against A. fumigatus in the innate immune responses.

TREM-1 siRNA对内毒素刺激巨噬细胞株RAW264.7分泌炎性因子影响

目的探讨靶向小鼠髓样细胞触发受体1(triggering receptor expressed on myeloid cells-1,TREM-1)的小分子干扰RNA(small interfering RNA,siRNA)在体外对内毒素刺激小鼠巨噬细胞株RAW264.7分泌肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白细胞介素1β(interleukin 1β,IL-1β)的抑制作用。方法合成1条靶向小鼠TREM-1分子的siRNA序列,以增强型绿色荧光蛋白(EGFP)作为报告因子,荧光显微镜观察EGFP的荧光强度,验证siRNA序列的干扰率。以pLKO1.1为载体构建针对TREM-1的pLKO1.1-TREM1-shRNA干扰质粒。将小鼠巨噬细胞株RAW264.7分为4组:空白组;内毒素组(LPS组);空质粒组(pLKO1.1组):采用脂质体法将pLKO1.1转染细胞;干扰组(siRNA组):将pLKO1.1-TREM1-shRNA转染细胞;转染72 h后用内毒素刺激24 h,并以实时定量PCR分别检测TREM-1、TNF-α与IL-1β的表达;以ELISA分别检测上清液中TNF-α、IL-1β含量。结果与LPS组比较,siRNA组中TREM-1、TNF-α、IL-1β的mRNA显著下降(P<0.01),上清液中TNF-α、IL-1β含量明显降低(P<0.01)。结论小分子干扰RNA可能通过抑制TREM-1基因的表达而减少内毒素诱导小鼠巨噬细胞264.7中TNF-α、IL-1β的分泌。

Application of TREM-1 in peripheral blood as a switching point for sequential ventilation of patients with chronic obstructive pulmonary disease complicated with respiratory failure

Objective:To investigate the application of peripheral blood triggering receptor expressed on myeloid cells-1(TREM-1)for sequential treatment switching points in patients with chronic obstructive pulmonary disease(COPD)complicated with respiratory failure.Methods:A total of 120 cases of COPD patients with respiratory failure from June 2017 to December 2018 were randomly divided into two groups:60 cases in the control group and 60 cases in the observation group.The control group received spontaneous breathing trials for 2 h to select the time for non-invasive positive pressure ventilation,while the observation group received peripheral blood TREM-1(≤90.0 pg/mL)to select the time for non-invasive positive pressure ventilation.The stress hormones,clinical pulmonary infection score and vital signs of two groups after 24 h of mechanical ventilation were detected.The treatment time and the adverse reactions of the two groups were recorded.Results:There was no significant difference in rennin,adrenaline,noradrenaline and angiotensin II between two groups(P>0.05).Compared with the control group,the clinical pulmonary infection score was decreased in the observation group(P<0.05).There was no significant difference in heart rate,respiratory rate,pH,partial pressure of carbon dioxide and partial pressure of oxygen between two groups(P>0.05).There was no significant difference in intensive care monitoring time between two groups(P>0.05).Compared with the control group,the observation group had no significant difference in invasive ventilation time and total mechanical ventilation.The time of hospitalization and hospitalization had significantly decreased(P<0.05).There was no significant difference in mortality,ventilator-associated pneumonia and re-intubation between two groups(P>0.05).Conclusion:TREM-1 can be used as a switching point during invasive-noninvasive sequential ventilation for COPD patients with respiratory failure,which can shorten the time of invasive ventilation,total mechanical ventilation and hospitalization.

Soluble Triggering Receptor Expressed on Myeloid Cells-1 and Inflammatory Markers in Colorectal Cancer Surgery： A Prospective Cohort Study

Background： Major abdominal surgery, including colorectal cancer （CRC） surgery, leads to systemic inflammatory response syndrome that can be detected and monitored with inflammatory markers testing. The aims of the study were to evaluate the usefulness of soluble triggering receptor expressed on myeloid cells-l （sTREM-1 ）, interleukin-6 （IL-6）, procalcitonin （PCT）, and C-reactive protein （CRP） in following the inflammatory response in CRC surgery and postoperative period, as well as to determine if duration of the surgery and the time that the colon has been opened during the surgery （open colon time [OCT]） refect a larger surgical stress through inflammatory markers rise. Methods： The study included 20 patients who underwent CRC surgery and 19 healthy volunteers from June 2011 to September 2012. We determined inflammatory markers 1 day before surgery （T0）, 24 h （T1）, 48 h （T2）, and 7 days after the surgery （T3）. All statistical analyses were calculated using MedCalc Statistical Software version 14.8.1 （MedCalc Software bvba, Ostend, Belgium）. Results： Concentrations ofCRP, PCT, and I L-6 in all measurement times were statistically different and sTREM- 1 did not yield statistical significance. A weak positive correlation was/bund between l L-6 in T 1 and T2 with the duration of the surgery （T 1 ： r= 0.4060, P 〈 0.0001 ; T2：r =0.3430, P〈0.0001）andOCT（T1：r= 0.3640, P〈0.0001,T2：r=0.3430, P〈0.0001）.AweakpositivecorrelationbetweenCRP in T2 and OCT （r = 0.4210, P 〈 0.0001 ） was also found. The interconnectivity of tested parameters showed a weak positive correlation between CRP and IL-6 in T1 （r= 0.3680; P 〈 0.0001 ）, moderate positive correlation in T2 （r = 0.6770; P 〈 0.0001）, and a strong positive correlation in T3 （r = 0.8651; P 〈 0.0001）. Conclusions： CRP, IL-6, and PCT were shown to be reliable for postoperative monitoring. Simultaneous determination of CRP and IL-6 might not be useful as they follow similar kinetics, sTREM- 1 might not be useful in CRC postoperative monitoring.

小分子干扰RNA沉默髓样细胞触发受体1对内毒素诱导小鼠巨噬细胞株RAW264.7分泌炎性因子的影响

目的利用小分子干扰RNA探讨髓样细胞触发受体1在内毒素刺激小鼠巨噬细胞株RAW264.7分泌肿瘤坏死因子α、白细胞介素1β中的作用。方法设计并合成干扰率高的小分子干扰RNA,以pLKO1.1为载体构建pLKO1.1-髓样细胞触发受体1干扰质粒。将小鼠巨噬细胞株RAW264.7分为4组:空白组;内毒素组;空质粒组(pLKO1.1组):采用脂质体法将pL-KO1.1转染细胞;干扰组(小分子干扰RNA组):将pLKO1.1-髓样细胞触发受体1转染细胞,内毒素刺激24 h后实时定量PCR分别检测髓样细胞触发受体1、肿瘤坏死因子α与白细胞介素1β的mRNA水平;以ELISA法分别检测细胞上清液中肿瘤坏死因子α、白细胞介素1β含量。结果与内毒素组比较,小分子干扰RNA组细胞中髓样细胞触发受体1、肿瘤坏死因子α、白细胞介素1β的mRNA含量显著下降(P<0.01);细胞培养上清液中肿瘤坏死因子α、白细胞介素1β含量明显降低(P<0.01)。结论小分子干扰RNA可能通过抑制髓样细胞触发受体1基因的表达而减少内毒素诱导的小鼠巨噬细胞RAW264.7中肿瘤坏死因子α、白细胞介素1β的分泌。