The production of pulmonary surfactant, a complex of phospholipids and lung-specific surfactant proteins, is a primary function of alveolar type II cells. Although previous studies have demonstrated a role for cell-extracellular matrix interactions and normal cell shape in the maintenance of differentiated function in primary cultures of adult rat type II cells, a positive role for growth factors in surfactant protein gene expression in isolated normal adult type II cells has not been reported. In the present study, we have examined the effects of a panel of hormones, growth factors, and cytokines on the expression of mRNAs for surfactant proteins A, B, and C (SP-A, SP-B, and SP-C). Our results show that keratinocyte growth factor (KGF) induced a two- to threefold increase in steady-state levels of mRNAs for SP-A and SP-B, but had no effect on or decreased SP-C mRNA. The increase in SP-A mRNA was accompanied by an increase in SP-A protein. The effects of KGF were both dose and time dependent, and they could be neutralized by a monoclonal antibody against KGF. The effects of KGF were mimicked by acidic fibroblast growth factor, which will bind the KGF receptor. We conclude that KGF can support differentiation of alveolar type II cells as well as act as a mitogen, thus suggesting an important role for KGF in maintenance of the alveolar epithelium.

This study suggests that there is a strong indication for LMCT for HCCs measuring 40 mm or less in diameter and those located on the liver surface even if they are as large as 50 mm, but not for those located close to the gallbladder or in contact with the diaphragm. LMCT appears to be applicable in patients with impaired liver function.

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Although alveolar reorganization after acute lung injury depends on regeneration of alveolar epithelial cells, there is little knowledge of regulation of pulmonary healing process. Transcription factors may play key roles in this regulation. To investigate whether the CCAAT enhancer binding protein (C/EBP) family, alpha, beta, and delta, were involved in alveolar reorganization after injury, we examined expression of C/EBP proteins and mRNAs in lung injuries induced by lipopolysaccharide (LPS) or bleomycin (Bleo) and in cell proliferation by keratinocyte growth factor (KGF). By immunohistochemistry, we demonstrated that C/EBP alpha and C/EBP beta were expressed in alveolar type II cells and alveolar macrophages, but C/EBP delta was expressed restrictedly in some of alveolar type II cells in a spatial pattern in the control lungs. Further, these three C/EBP family members were differentially expressed in alveolar cell proliferation and in acute lung injury, in which, interestingly, C/EBP alpha and C/EBP delta were reciprocally expressed in alveolar type II cell proliferation and in pulmonary fibrosis. However, expressions of their mRNAs by in situ hybridization were dramatically increased in the affected lesions of the lungs by LPS and Bleo, and Northern blot analysis showed an increased abundance of the mRNA for C/EBP beta in LPS-treated lungs and for C/EBP delta in Bleo-treated lungs, compared with those in the control lungs. Thus, differential expression of the C/EBP family may be required to maintain and reorganize the basic integrity of alveolar structure during pathological states, which suggests an important role for the C/EBP family in maintaining normal alveolar architecture and function and in repairing the damaged epithelium after injury.

The lung-specific surfactant proteins (SP) are essential for normal respiratory function. Transcription factors may play an important role in the regulation of surfactant proteins. The CCAAT/enhancer-binding protein (C/EBP) family consists of transcription factors that can stimulate expression of genes in lipid-metabolizing epithelial cells. C/EBPα-deficient mice have been shown to exhibit abnormal pulmonary histopathology. Recently, we demonstrated that C/EBP family members are differentially expressed in alveolar type II cell proliferation and in pulmonary fibrosis. In the present study, to investigate whether the C/EBP family would be involved in the regulation of surfactant proteins, we examined the protein expression of SP-A, and SP-C, and mRNA expression of SP-A, SP-B, and SP-C in the lungs from newborn C/EBPα-deficient mice. Using immunohistochemistry, we demonstrated that positive cells for SP-C, specific to alveolar type II cells, in the lungs were more abundant in the newborn C/EBPα-deficient mice than in control mice, which suggests the hyperproliferation of alveolar type II cells in the lungs of the C/EBPα-deficient mice. In situ hybridization analysis revealed that expression of SP-A, SP-B, and SP-C mRNAs were increased in the lungs of newborn C/EBPα-deficient mice. Northern blot analysis revealed that surfactant protein mRNAs were also increased. Thus, these results suggest that C/EBPα may play a key role in the proliferation of alveolar type II cells and the regulation of genes of surfactant protein.

The active transcellular transport of electrolytes across the alveolar epithelium probably plays an important role in alveolar fluid homeostasis by helping to maintain the alveolus relatively free of fluid. To better understand the factors regulating active ion transport across alveolar epithelial cells, we examined the effect of a number of pharmacologically active agents on the bioelectric properties of alveolar type II cells in primary culture. Alveolar type II cells were isolated from adult male rats and cultured on collagen-coated Millipore filters for 6-14 days. The bioelectric properties of these monolayers were determined in Ussing-type chambers. The addition of 10(-3) M 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) increased the short-circuit current (Isc) from 2.9 +/- 0.75 to 6.9 +/- 0.73 microA/cm2 (means +/- SE; n = 8) and decreased the transepithelial resistance. Cholera toxin, 3-isobutyl-1-methylxanthine, and terbutaline sulfate produced similar increases in Isc and decreases in resistance. The Isc stimulated by 8-BrcAMP was Na but not Cl dependent and could be blocked by amiloride but not by furosemide. Thus 8-BrcAMP and agents that increase intracellular cAMP can stimulate a Na-dependent net active ion transport across alveolar type II cell monolayers. Similar regulatory mechanisms may be involved in controlling solute and fluid movement across the alveolar epithelium in vivo.

Background Spasticity and rigidity are serious complications associated with spinal traumatic or ischemic injury. Clinical studies show that Tizanidine (Tiz) is an effective anti-spasticity agent, however, the mechanism of this effect is still not clear. Tiz binds not only to α2-adrenoreceptors (AR) but also to imidazoline (I) receptors. Both receptor systems (AR+I) are present in the spinal cord interneurons and α-motoneurons. The aim of the present study was to evaluate the therapeutic potency of systematically or spinally (intrathecally) delivered Tiz on stretch reflex activity (SRA) in animals with ischemic spasticity, and to delineate supraspinal or spinal sites of Tiz action. Methods Animals were exposed to 10 min of spinal ischemia to induce an increase in SRA. Increase in SRA was identified by simultaneous increase in recorded EMG activity and ankle resistance measured during computer-controlled ankle dorsiflexion (40°/3 sec) in fully awake animals. Animals with increased SRA were divided into several experimental subgroups and treated as follows: i) Tiz administered systemically at the dose of 1 mg kg-1, or intrathecally (IT) at 10 μg or 50 μg delivered as a single dose; ii) Treatment with systemic Tiz was followed by the systemic injection of vehicle, or by non-selective AR antagonist without affinity for imidazoline receptors; Yohimbine (Yoh), α2A AR antagonist; BRL44408 (BRL), α2B AR antagonist; ARC239 (ARC), non-selective AR and I1 receptor antagonist; Efaroxan (Efa), or non-selective AR and I2 receptor antagonist; Idazoxan (Ida); iii) Treatment with IT Tiz was followed by the IT injection of selective α2A AR antagonist; Atipamezole (Ati). In a separate group of spastic animals the effect of systemic Tiz treatment (1 mg/kg) or isoflurane anesthesia on H-reflex activity was also studied. Results Systemic and/or IT treatment with Tiz significantly suppressed SRA. This Tiz-mediated anti-SRA effect was reversed by BRL (5 mg kg-1), Efa (1 mg kg-1) and Ida (1 mg kg-1). No reversal was seen after Yoh (3 mg kg-1) or ARC (5 mg kg-1) treatment. Anti-SRA induced by IT Tiz (50 μg) was reversed by IT injection of Ati (50 μg). Significant suppression of H-reflex was measured after systemic Tiz treatment (1mg/kg) or isoflurane (2%) anesthesia, respectively. Immunofluoresecene staining of spinal cord sections taken from animals with spasticity showed upregulation of α-2A receptor in activated astrocytes. Conclusions These data suggest that α2A AR and I receptors, but not α2B AR primarily mediate the Tiz-induced anti-spasticity effect. This effect involves spinal and potentially supraspinal sites and likely targets α2A receptor present on spinal neurons, primary afferents and activated astrocytes Further studies using highly selective antagonists are needed to elucidate the involvement of specific subtypes of the AR and imidazoline receptors in the anti-spasticity effect seen after Tiz treatment.

Toll-like receptor 5 (TLR5) recognizes bacterial flagellin and activates host inflammatory responses, mainly through activation of the NF-κB pathway. Although pulmonary fibrosis occurs in some cases of lung infection by flagellated bacteria, the pathological roles of TLR5 stimulation in pulmonary fibrosis have yet to be elucidated. In the present study, we first confirmed that flagellin activated the NF-κB pathway in cultured A549 alveolar epithelial cells. Next, we examined the types of genes whose expression was modulated by flagellin in the cells. Microarray analysis of gene expression indicated that flagellin induced a change in gene expression that had a similar trend to transforming growth factor-β1 (TGF-β(1)), a key factor in the induction of epithelial-mesenchymal transition (EMT). Biochemical analysis revealed that TGF-β(1) and flagellin increased the level of fibronectin protein, while they reduced the level of E-cadherin protein after 30 h of treatment. Interestingly, simultaneous treatment with TGF-β(1) and flagellin significantly augmented these EMT-related changes. Flagellin strongly activated p38 MAP kinase, and the activation was sustained for longer than 30 h. SB203580, an inhibitor of p38 MAP kinase, inhibited the upregulation of fibronectin by both flagellin and TGF-β(1). Simultaneous treatment with TGF-β(1) and flagellin augmented the activation of p38 MAP kinase by TGF-β(1) or flagellin alone. These results strongly suggest that flagellin cooperates with TGF-β(1) in the induction of EMT in alveolar epithelial cells.