KLF4 Inhibits the Activation of Human Hepatic Stellate Cell In Vitro.

OBJECTIVE: Hepatic stellate cells (HSCs) play a crucial role in liver fibrosis. Early-stage liver fibrosis is reversible and intimately associated with the state of HSCs. Kruppel-like factor 4 (KLF4) plays a pivotal role in a wide array of physiological and pathological processes. This study aimed to investigate the effect of KLF4 on the proliferation, apoptosis and phenotype of quiescent HSCs METHODS: We designed a KLF4 lentiviral vector and a KLF4 siRNA lentiviral vector, to upregulate and silence KLF4 expression in human HSC LX-2 cells via transfection. Cell proliferation was assessed using the CCK-8 assay. Flow cytometry was used to detect the cell cycle distribution and apoptosis rate. Western blotting was used to determine the levels of some quiescence and activation markers of HSCs RESULTS: Overexpression of KLF4 significantly increased the levels of E-cadherin and ZO-1, which are quiescent HSC markers, while significantly decreased the levels of N-cadherin and a-SMA, known activated HSC markers. In contrast, cell proliferation and apoptosis rates were elevated in LX-2 cells in which KLF4 expression was silenced CONCLUSION: KLF4 inhibits the proliferation and activation of human LX-2 HSCs. It might be a key regulatory protein in the maintenance of HSC quiescence and may serve as a target for the inhibition of hepatic fibrosis.

Overexpression of miR-24 Is Involved in the Formation of Hypocoagulation State after Severe Trauma by Inhibiting the Synthesis of Coagulation Factor X.

BACKGROUND: Dysregulation of microRNAs may contribute to the progression of trauma-induced coagulopathy (TIC). We aimed to explore the biological function that miRNA-24-3p (miR-24) might have in coagulation factor deficiency after major trauma and TIC. METHODS: 15 healthy volunteers and 36 severe trauma patients (Injury Severity Score ≥ 16 were enrolled. TIC was determined as the initial international normalized ratio >1.5. The miR-24 expression and concentrations of factor X (FX) and factor XII in plasma were measured. In vitro study was conducted on L02 cell line. RESULTS: The plasma miR-24 expression was significantly elevated by 3.17-fold (P = 0.043) in major trauma patients and reduced after 3 days (P < 0.01). The expression level was significantly higher in TIC than in non-TIC patients (P = 0.040). Multivariate analysis showed that the higher miR-24 expression was associated with TIC. The plasma concentration of FX in TIC patients was significantly lower than in the non-TIC ones (P = 0.030) and controls (P < 0.01). A negative correlation was observed between miR-24 and FX. miR-24 transduction significantly reduced the FX level in the supernatant of L02 cells (P = 0.030). CONCLUSIONS: miR-24 was overexpressed in major trauma and TIC patients. The negative correlation of miR-24 with FX suggested the possibility that miR-24 might inhibit the synthesis of FX during TIC.

Effect of Kruppel-like factor 4 on Notch pathway in hepatic stellate cells.

The relationship between Kruppel-like factor 4 (KLF4) and the Notch pathway was determined to investigate the effect of KLF4 on the activation of hepatic stellate cells and underlying mechanisms. Fifty SPF BALB/c mice were randomly divided into two groups. A liver fibrosis model was established in 25 mice as the experimental group, and the remaining 25 mice served as controls. On the day 0, 7, 14, and 35, liver tissues were removed for immunofluorescent detection. The Notch pathway inhibitor DAPT was added to the primary original hepatic stellate cells, and KLF4 and Notch-associated factor expression was detected by qRT-PCR. Additionally, the hepatic stellate cell line LX-2 was used to establish control and experimental groups, and was cultured in vitro. LX-2 cells in the experimental groups were treated with DAPT and the Notch activator transforming growth factor-beta 1 separately, whereas those in the control group were given isotonic culture medium. After 48 h, KLF4 expression was examined by Western blotting. After transient transfection of LX-2 cells to increase KLF4, the expression of Notch factor was examined. Immunofluorescence analysis showed that, with the aggravation of liver fibrosis, the absorbance (A) values of KLF4 were decreased (day 0: 980.73±153.19; day 7: 1087.99±230.23; day 14: 390.95±93.56; day 35: 245.99±87.34). The expression of Notch pathway- related factors (Notch-1, Notch-2, and Jagged-1) in the hepatic stellate cell membrane was negatively correlated to KLF4 expression. With the increase of KLF4 expression, Notch-2 (0.73±0.13) and Jagged-1 (0.43±0.12) expression decreased, whereas Notch-1 level was not detectable. When the Notch pathway was inhibited, KLF4 levels generally increased (18.12±1.31). Our results indicate that KLF4 expression is negatively correlated to the Notch pathway in hepatic stellate cells, which may provide a reference for the treatment of hepatic fibrosis.

Inhibition of complement C3 might rescue vascular hyporeactivity in a conscious hemorrhagic shock rat model.

BACKGROUND: Vascular hyporeactivity in severe hemorrhagic shock could induce refractory hypotension and is an important cause of death. The global acute inflammatory response induced in shock triggers the over-expression of reactive oxygen species, NO, ET1 and TNF-α, which play essential roles in the pathology of vascular hyporeactivity. This leads to a hypothesis that inhibition of the complement system, the mediator of the inflammatory cascade, might be a promising therapeutic exploration for vascular hyporeactivity. METHODS: We use cobra venom factor (CVF) and the soluble form of CR1 (sCR1) which deplete or inhibit complement C3 respectively to examine its role in vascular hyporeactivity in a conscious hemorrhagic shock rat model. RESULTS: We first confirmed the over-activation of C3 during shock and the down-regulation effects of CVF and sCR1 on C3. Then, both CVF and sCR1 could significantly mitigate the over-expression of serum NO, ET-1, TNF-α and reactive oxygen species. Finally, the vascular reactivity of superior mesenteric arteries (SMA) was examined in vitro, which confirmed the massive reduction of vascular reactivity in shock, which was significantly rescued by both CVF and sCR1. CONCLUSIONS: Inhibition of C3 might improve the reactivity of SMA to norepinephrine during hemorrhagic shock possibly through the downregulation of NO, ET1, TNF-α and reactive oxygen radicals.