RESUMEN
Acute lung injury is a common complication of sepsis in intensive care unit patients with an extremely high mortality. The present study investigated the effects of calcitriol, the active form of vitamin D, on tumor necrosis factor alpha (TNF-α) and macrophage inflammatory protein-2 (MIP-2) in sepsis-induced acute lung injury. Mice were intraperitoneally (i.p.) injected with lipopolysaccharide (LPS, 1.0mg/kg) to establish the animal model of sepsis-induced acute lung injury. Some mice were i.p. injected with calcitriol (1.0µg/kg) before LPS injection. An obvious infiltration of inflammatory cells in the lungs was observed beginning at 1h after LPS injection. Correspondingly, TNF-α and MIP-2 in sera and lung homogenates were markedly elevated in LPS-treated mice. Interestingly, calcitriol obviously alleviated LPS-induced infiltration of inflammatory cells in the lungs. Moreover, calcitriol markedly attenuated LPS-induced elevation of TNF-α and MIP-2 in sera and lung homogenates. Further analysis showed that calcitriol repressed LPS-induced p38 mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) phosphorylation. In addition, calcitriol blocked LPS-induced nuclear translocation of nuclear factor kappa B (NF-κB) p65 and p50 subunit in the lungs. Taken together, these results suggest that calcitriol inhibits inflammatory cytokines production in LPS-induced acute lung injury.
Asunto(s)
Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/tratamiento farmacológico , Calcitriol/farmacología , Calcitriol/uso terapéutico , Quimiocina CXCL2/metabolismo , Lipopolisacáridos/toxicidad , Factor de Necrosis Tumoral alfa/metabolismo , Lesión Pulmonar Aguda/sangre , Lesión Pulmonar Aguda/metabolismo , Animales , Quimiocina CXCL2/sangre , Ensayo de Inmunoadsorción Enzimática , Immunoblotting , Masculino , Ratones , Factor de Necrosis Tumoral alfa/sangreRESUMEN
Early pulmonary inflammation and epithelial-mesenchymal transition (EMT) play important roles during lung fibrosis. Increasing evidence demonstrates that calcitriol, the active form of vitamin D3, has anti-inflammatory activities. The aim of this study was to investigate the effects of calcitriol on bleomycin (BLM)-induced early pulmonary inflammation and subsequent EMT. Mice were intratracheally injected with BLM (3.0mg/kg). In three calcitriol+BLM groups, mice were intraperitoneal (i.p.) injected with different doses of calcitriol (0.2, 1.0 or 5.0 µg/kg) daily, beginning at 48 h before BLM injection. Twenty-four hours, seven and fourteen days after BLM injection, pulmonary inflammation and EMT were evaluated. As expected, BLM-induced infiltration of inflammatory cells in the lungs was attenuated by calcitriol. BLM-induced pulmonary inflammatory cytokines were repressed by calcitriol. Moreover, BLM-induced nuclear translocation of nuclear factor kappa B (NF-κB) p65 was blocked by calcitriol. In addition, BLM-induced phosphorylation of pulmonary p38 MAPK and protein kinase B (Akt) was inhibited by calcitriol. Further analysis showed that BLM-induced α-smooth muscle actin (α-SMA), a marker for EMT in the lungs, was significantly attenuated by calcitriol. BLM-induced transforming growth factor-beta 1 (TGF-ß1) up-regulation and Smad phosphorylation were attenuated by calcitriol. In conclusion, calcitriol inhibits BLM-induced early pulmonary inflammation and subsequent EMT.
Asunto(s)
Bleomicina/toxicidad , Calcitriol/farmacología , Transición Epitelial-Mesenquimal/efectos de los fármacos , Actinas/genética , Actinas/metabolismo , Animales , Antiinflamatorios/farmacología , Marcadores Genéticos , Pulmón/efectos de los fármacos , Pulmón/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Fosforilación , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Fibrosis Pulmonar/inducido químicamente , Fibrosis Pulmonar/tratamiento farmacológico , Factor de Transcripción ReIA/antagonistas & inhibidores , Factor de Transcripción ReIA/genética , Factor de Transcripción ReIA/metabolismo , Factor de Crecimiento Transformador beta1/antagonistas & inhibidores , Factor de Crecimiento Transformador beta1/genética , Factor de Crecimiento Transformador beta1/metabolismo , Regulación hacia Arriba , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidores , Proteínas Quinasas p38 Activadas por Mitógenos/genética , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
A recent report showed that unfolded protein response (UPR) signaling was activated during bleomycin (BLM)-induced pulmonary fibrosis. Phenylbutyric acid (PBA) is an endoplasmic reticulum (ER) chemical chaperone that inhibits the UPR signaling. The present study investigated the effects of PBA on BLM-induced epithelial-mesenchymal transition (EMT) and pulmonary fibrosis. For induction of pulmonary fibrosis, all mice except controls were intratracheally injected with a single dose of BLM (3.0mg/kg). In PBA+BLM group, mice were intraperitoneally injected with PBA (150mg/kg) daily. Three weeks after BLM injection, EMT was measured and pulmonary fibrosis was evaluated. BLM-induced pulmonary UPR activation was inhibited by PBA. Moreover, BLM-induced pulmonary nuclear factor kappa B (NF-κB) p65 activation was blocked by PBA. In addition, BLM-induced up-regulation of pulmonary inflammatory cytokines was repressed by PBA. Further analysis showed that BLM-induced α-smooth muscle actin (α-SMA), a marker for EMT, was significantly attenuated by PBA. Moreover, BLM-induced pulmonary collagen (Col1α1 and Col1α2) was obviously inhibited by PBA. Importantly, BLM-induced pulmonary fibrosis, as determined using Sirius red staining, was obviously alleviated by PBA. Taken together, these results suggest that PBA alleviates ER stress-mediated EMT in the pathogenesis of BLM-induced pulmonary fibrosis.