[LIMR is involved in the inhibitory effect of antiflammin-1 on epithelial-mesenchymal transition in A549 cells].

Epithelial-mesenchymal transition (EMT) occurring in alveolar epithelial cells plays an important role in the development and progression of pulmonary fibrosis. Previous studies showed that antiflammin-1 (the active fragment of uteroglobin) effectively inhibited bleomycin-induced pulmonary fibrosis. However, its mechanism is still far from being clarified. In this study, we investigated the effects of antiflammin-1 on EMT in A549 cells induced by transforming growth factor-ß1 (TGF-ß1) and the underlying mechanism by using morphological observation and Western blot. The results showed that the expression of α-smooth muscle actin (α-SMA) increased significantly while the expression of E-cadherin decreased significantly in A549 cells following treatment with TGF-ß1 concomitant with morphological change of A549 cells from pebble-like shape epithelial cells to spindle-like mesenchymal shape. This process of EMT in A549 cells induced by TGF-ß1 was significantly inhibited when A549 cells were co-incubated with TGF-ß1 and antiflammin-1. Furthermore, the anti-lipocalin interacting membrane receptor (LIMR) antibody and PD98059 (an ERK signaling pathway blocker) attenuated the inhibitory effect of antiflammin-1 on TGF-ß1-induced EMT, respectively. Our findings indicate that antiflammin-1 can inhibit EMT in A549 cells induced by TGF-ß1, which is related to LIMR and its downstream ERK signaling pathway.

A Sustained Activation of Pancreatic NMDARs Is a Novel Factor of ß-Cell Apoptosis and Dysfunction.

Type 2 diabetes, which features ß-cell failure, is caused by the decrease of ß-cell mass and insulin secretory function. Current treatments fail to halt the decrease of functional ß-cell mass. Strategies to prevent ß-cell apoptosis and dysfunction are highly desirable. Recently, our group and others have reported that blockade of N-methyl-d-aspartate receptors (NMDARs) in the islets has been proposed to prevent the progress of type 2 diabetes through improving ß-cell function. It suggests that a sustained activation of the NMDARs may exhibit deleterious effect on ß-cells. However, the exact functional impact and mechanism of the sustained NMDAR stimulation on islet ß-cells remains unclear. Here, we identify a sustained activation of pancreatic NMDARs as a novel factor of apoptotic ß-cell death and function. The sustained treatment with NMDA results in an increase of intracellular [Ca2+] and reactive oxygen species, subsequently induces mitochondrial membrane potential depolarization and a decrease of oxidative phosphorylation expression, and then impairs the mitochondrial function of ß-cells. NMDA specifically induces the mitochondrial-dependent pathway of apoptosis in ß-cells through upregulation of the proapoptotic Bim and Bax, and downregulation of antiapoptotic Bcl-2. Furthermore, a sustained stimulation of NMDARs impairs ß-cell insulin secretion through decrease of pancreatic duodenal homeobox-1 (Pdx-1) and adenosine triphosphate synthesis. The activation of nuclear factor-κB partly contributes to the reduction of Pdx-1 expression induced by overstimulation of NMDARs. In conclusion, we show that the sustained stimulation of NMDARs is a novel mediator of apoptotic signaling and ß-cell dysfunction, providing a mechanistic insight into the pathological role of NMDARs activation in diabetes.

Antiflammin-1 attenuates bleomycin-induced pulmonary fibrosis in mice.

BACKGROUND: Antiflammin-1 (AF-1), a derivative of uteroglobin (UG), is a synthetic nonapeptide with diverse biological functions. In the present study, we investigated whether AF-1 has a protective effect against bleomycin-induced pulmonary fibrosis. METHODS: C57BL/6 mice were injected with bleomycin intratracheally to create an animal model of bleomycin-induced pulmonary fibrosis. On Day 7 and Day 28, we examined the anti-inflammatory effect and antifibrotic effect, respectively, of AF-1 on the bleomycin-treated mice. The effects of AF-1 on the transforming growth factor-beta 1 (TGF-ß1)-induced proliferation of murine lung fibroblasts (NIH3T3) were examined by a bromodeoxycytidine (BrdU) incorporation assay and cell cycle analysis. RESULTS: Severe lung inflammation and fibrosis were observed in the bleomycin-treated mice on Day 7 and Day 28, respectively. Administration of AF-1 significantly reduced the number of neutrophils in the bronchoalveolar lavage fluid (BALF) and the levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1ß) in the lung homogenates on Day 7. Histological examination revealed that AF-1 markedly reduced the number of infiltrating cells on Day 7 and attenuated the collagen deposition and destruction of lung architecture on Day 28. The hydroxyproline (HYP) content was significantly decreased in the AF-1-treated mice. In vitro, AF-1 inhibited the TGF-ß1-induced proliferation of NIH3T3 cells, which was mediated by the UG receptor. CONCLUSIONS: AF-1 has anti-inflammatory and antifibrotic actions in bleomycin-induced lung injury. We propose that the antifibrotic effect of AF-1 might be related to its suppression of fibroblast growth in bleomycin-treated lungs and that AF-1 has potential as a new therapeutic tool for pulmonary fibrosis.