Dysregulation of FTX/miR‐545 signaling pathway downregulates Tim‐3 and is responsible for the abnormal activation of macrophage in cirrhosis

Abstract

Background Accumulating evidence has suggested the involvement of miR‐545 and long noncoding RNA (lncRNA) FTX in a wide range of diseases. Therefore, this study aimed to investigate the molecular mechanism underlying the function of miR‐545 and lncRNA FTX in hepatitis B virus (HBV)‐related cirrhosis. Method The level of Tim‐3, TLR‐4, and endotoxin was detected in CD14+, CD14 +CD16 +, and CD14 +CD16 − monocytes isolated from both patients with cirrhosis and healthy controls. ELISA assays were performed to detect the effect of Lipopolysaccharide (LPS) or FTX on the expression of tumor necrosis factor alpha (TNF‐a), interleukin‐6 (IL‐6), IL‐1β, and Nuclear factor kB (NF‐kB). In‐silico analysis, luciferase assay, real‐time polymerase chain reaction (PCR), and Western blot analysis were utilized to determine the regulatory relationship between miR‐545 and Tim‐3. Results The levels of Tim‐3, Tim‐3 MIF and endotoxin were reduced in the CD14+ monocytes isolated from patients with cirrhosis. In addition, the level of Tim‐3 was also decreased in the CD14 +CD16 − monocytes isolated from patients with cirrhosis, whereas the level of Tim‐3 in CD14 +CD16 + monocytes showed no evident difference between healthy controls and patients with cirrhosis. Furthermore, TLR‐4 was highly expressed in CD14 +CD16 + monocytes isolated from patients with cirrhosis, whereas Tim‐3 was negatively regulated by endotoxin and the correlation coefficient was ‐0.5287. After the LPS stimulation, although the level of TNF‐a, IL‐6, IL‐1β, and NF‐kB was higher in both patients with cirrhosis and healthy controls, the effect of LPS in patients with cirrhosis was much more significant. In addition, the cirrhosis group showed a lower level of FTX and Tim‐3, but a higher level of miR‐545. Moreover, miR‐545 directly bound to the 3′untranslated region (3′UTR) of Tim‐3 and inhibited the luciferase activity of cells cotransfected with miR‐545 mimics and wild‐type 3′UTR of Tim‐3. Furthermore, FTX downregulated the expression of miR‐545, TNF‐a, IL‐6, IL‐1β, and NF‐kB, but upregulated the expression of Tim‐3. Conclusion The results of this study confirmed the effect of FTX, miR‐545, and Tim‐3 on the expression of inflammatory cytokines, the lymphocyte/monocyte ratio, and the severity and prognosis of HBV‐related cirrhosis.

Long noncoding RNAs in hepatitis B virus replication and oncogenesis

“…LncRNA FTX downregulates the expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β, and nuclear factor kB (NF-kB) but upregulates the expression of Tim-3. This result demonstrated the effect of FTX on the expression of inflammatory cytokines through FTX-miR-545-TIM3 axis[ 22 ].…”

“…LncRNA Ftx is transcribed within the X-inactivation center[ 67 ]. Ftx encodes four miRNA clusters in its introns, among them, miR-545/374a located in intron b of Ftx has been implicated in HBV-associated HCC[ 22 ]. Expression of miR-374a and miR-545 was significantly higher in tumor tissues of HBV-related HCC.…”

Current State and Progress of Research on the Role of lncRNA in HBV-Related Liver Cancer

“…The expression of miR-545/374a clusters was significantly upregulated in HBV-related HCC tissue, promoting the proliferation, migration, and invasion of HCC cells and being associated with a poor prognosis in HCC patients. The molecular mechanism of miR-545 and lncRNA FTX in HBV-associated cirrhosis has been explored ( Liu et al., 2018 ). An important regulatory pathway has been discovered and confirmed in which lncRNA FTX/microRNA-545 regulates Tim-3 expression and affects the secretion of multiple inflammatory factors mainly by binding to ligand galactagglutinin-9 (galectin-9).…”

CircPRKCI relieves lipopolysaccharide‐induced HK2 cell injury by upregulating the expression of miR‐545 target gene ZEB2

“…15,16 miR-545 was reported to be an important signal in mediating the inflammatory macrophage reactions of cirrhosis by targeting Tim-3. 17 But few reports show the correlation of miR-545 in sepsis. However, Cheng et al proved that circPRKCI regulates the peroxide-induced neuron injury by sponging miR-545.…”