Foxm1 transcription factor is required for lung fibrosis and epithelial-to-mesenchymal transition

Alveolar epithelial cells (AECs) participate in the pathogenesis of pulmonary fibrosis, producing pro-inflammatory mediators and undergoing epithelial-to-mesenchymal transition (EMT). Herein, we demonstrated the critical role of Forkhead Box M1 (Foxm1) transcription factor in radiation-induced pulmonary fibrosis. Foxm1 was induced in AECs following lung irradiation. Transgenic expression of an activated Foxm1 transcript in AECs enhanced radiation-induced pneumonitis and pulmonary fibrosis, and increased the expression of IL-1β, Ccl2, Cxcl5, Snail1, Zeb1, Zeb2 and Foxf1. Conditional deletion of Foxm1 from respiratory epithelial cells decreased radiation-induced pulmonary fibrosis and prevented the increase in EMT-associated gene expression. siRNA-mediated inhibition of Foxm1 prevented TGF-β-induced EMT in vitro. Foxm1 bound to and increased promoter activity of the Snail1 gene, a critical transcriptional regulator of EMT. Expression of Snail1 restored TGF-β-induced loss of E-cadherin in Foxm1-deficient cells in vitro. Lineage-tracing studies demonstrated that Foxm1 increased EMT during radiation-induced pulmonary fibrosis in vivo. Foxm1 is required for radiation-induced pulmonary fibrosis by enhancing the expression of genes critical for lung inflammation and EMT.

Ethanol-induced impairment of spatial memory and brain matrix metalloproteinases

The formation of spatial memory appears to be dependent upon an intact hippocampus capable of the specific biochemical changes associated with synaptic remodeling. Hippocampal damage results in the disruption of synaptic remodeling and the acquisition of spatial memory tasks. Ethanol also disrupts normal hippocampal functioning and spatial memory. The present investigation established a dose-response relationship between ethanol treatment and impairment of spatial memory as measured using the circular water maze task. Intraperitoneal ethanol doses of 1.5 and 2 g/kg significantly increased the latency and distance swam to find the submerged pedestal as compared with a 1 g/kg dose, and 0.15 M NaCl vehicle control treatments. On days 2, 4, and 6 of acquisition animals were sacrificed and brain tissues were retained from the hippocampus, prefrontal neocortex, and cerebellum for measurement of matrix metalloproteinases (MMPs). The results indicated that ethanol treatment interfered with MMP-9, but not MMP-2, activity in the hippocampus, and to a lesser degree in the prefrontal cortex. No changes in the cerebellum were measured. Elevations in MMP activity appear to be a prerequisite to reconfiguration of extracellular matrix cell adhesion molecules thought to be important in the process of synaptic plasticity, which in turn appears to be necessary for memory consolidation. Thus, ethanol-induced impairment in the acquisition of spatial memory tasks may, in part, be due to disruption of brain MMP activity.