Oncostatin M and TNF-α Induce Alpha-1 Antitrypsin Production in Undifferentiated Adipose Stromal Cells

α1-Antitrypsin Binds to the Glucocorticoid Receptor with Anti-Inflammatory and Antimycobacterial Significance in Macrophages

α1-Antitrypsin (AAT), a serine protease inhibitor, is the third most abundant protein in plasma. Although the best-known function of AAT is irreversible inhibition of elastase, AAT is an acute-phase reactant and is increasingly recognized to have a panoply of other functions, including as an anti-inflammatory mediator and a host-protective molecule against various pathogens. Although a canonical receptor for AAT has not been identified, AAT can be internalized into the cytoplasm and is known to affect gene regulation. Because AAT has anti-inflammatory properties, we examined whether AAT binds the cytoplasmic glucocorticoid receptor (GR) in human macrophages. We report the finding that AAT binds to GR using several approaches, including coimmunoprecipitation, mass spectrometry, and microscale thermophoresis. We also performed in silico molecular modeling and found that binding between AAT and GR has a plausible stereochemical basis. The significance of this interaction in macrophages is evinced by AAT inhibition of LPS-induced NF-κB activation and IL-8 production as well as AAT induction of angiopoietin-like 4 protein, which are, in part, dependent on GR. Furthermore, this AAT-GR interaction contributes to a host-protective role against mycobacteria in macrophages. In summary, this study identifies a new mechanism for the gene regulation, anti-inflammatory, and host-defense properties of AAT.

Alpha-1 Antitrypsin Induces Epithelial-to-Mesenchymal Transition, Endothelial-to-Mesenchymal Transition, and Drug Resistance in Lung Cancer Cells

Purpose

Alpha-1 antitrypsin (A1AT) is a secreted protein that plays an important role in various diseases. However, the role of A1AT in non-small cell lung cancer is obscure.

Materials and Methods

A1AT expression in non-small cell lung cancer was analyzed using quantitative reverse transcription PCR, Western blotting (WB), immunohistochemistry (IHC), and ELISA. WB and IF were used to analyze markers of epithelial-to-mesenchymal transition (EMT), EndoMT, and cancer stem cell (CSC). Transwell and cell wound healing assays were used to analyze migration and invasion abilities. Colony formation and CCK-8 assays were used to analyze cell proliferation following cisplatin treatment.

Results

A1AT expression was higher in lung cancer samples than in normal tissues and the increased expression was correlated with poor overall survival of patients. In vitro experiments showed that A1AT overexpressed by plasmid transfection significantly promoted migration, invasion, EMT, EndoMT, stemness, and colony formation in lung cancer cell lines, as opposed to A1AT downregulation by siRNA transfection, which significantly inhibited all these variables.

Conclusion

A1AT is a novel therapeutic target and might be associated with tumor metastasis in lung carcinoma.

Immunosuppressive Drugs Alter α1-Antitrypsin Production in Hepatocytes: Implications for Epithelial Gap Repair

Immunosuppressive drugs are an inherent component of hematopoietic stem cell transplantation (HSCT) for the prevention of acute graft-versus-host disease (GVHD). Circulating α1-antitrypsin (AAT), a serine-protease inhibitor produced predominantly by hepatocytes that rises during acute phase responses, is lost in patient's stool due to gastrointestinal GVHD, and its augmentation has been found to attenuate GVHD. Here we explored the effect of immunosuppressive drugs on hepatocyte production of AAT and intestinal epithelial gap repair. The effect of commonly used immunosuppressants on AAT production was examined in vitro using HepG2 cells and primary mouse hepatocytes, and their impact on human intestinal epithelial cell line gap repair was evaluated. Sera from 12 allogeneic HSCT recipients, obtained at 14 days post-transplantation, predating the diagnosis of GVHD (n = 6), were examined for reepithelialization, with added clinical-grade AAT. Rapamycin compromised AAT production under inflammatory conditions. Mycophenolate mofetil and cyclosporine A (CSA) inhibited reepithelialization; AAT minimized the effect of CSA. Patient sera displayed superior gap repair with exogenous AAT. Functional insufficiency in circulating AAT may be the result of drug toxicities leading to ineffective gut reepithelization and compromised gut lining. Taken together, our data strengthen the rationale for incorporating AAT augmentation therapy into immunosuppressive treatment protocols.

Rapid clearance of heavy chain-modified hyaluronan during resolving acute lung injury

BACKGROUND

Several inflammatory lung diseases display abundant presence of hyaluronic acid (HA) bound to heavy chains (HC) of serum protein inter-alpha-inhibitor (IαI) in the extracellular matrix. The HC-HA modification is critical to neutrophil sequestration in liver sinusoids and to survival during experimental lipopolysaccharide (LPS)-induced sepsis. Therefore, the covalent HC-HA binding, which is exclusively mediated by tumor necrosis factor α (TNFα)-stimulated-gene-6 (TSG-6), may play an important role in the onset or the resolution of lung inflammation in acute lung injury (ALI) induced by respiratory infection.

METHODS

Reversible ALI was induced by a single intratracheal instillation of LPS or Pseudomonas aeruginosa in mice and outcomes were studied for up to six days. We measured in the lung or the bronchoalveolar fluid HC-HA formation, HA immunostaining localization and roughness, HA fragment abundance, and markers of lung inflammation and lung injury. We also assessed TSG-6 secretion by TNFα- or LPS-stimulated human alveolar macrophages, lung fibroblast Wi38, and bronchial epithelial BEAS-2B cells.

RESULTS

Extensive HC-modification of lung HA, localized predominantly in the peri-broncho-vascular extracellular matrix, was notable early during the onset of inflammation and was markedly decreased during its resolution. Whereas human alveolar macrophages secreted functional TSG-6 following both TNFα and LPS stimulation, fibroblasts and bronchial epithelial cells responded to only TNFα. Compared to wild type, TSG-6-KO mice, which lacked HC-modified HA, exhibited modest increases in inflammatory cells in the lung, but no significant differences in markers of lung inflammation or injury, including histopathological lung injury scores.

CONCLUSIONS

Respiratory infection induces rapid HC modification of HA followed by fragmentation and clearance, with kinetics that parallel the onset and resolution phase of ALI, respectively. Alveolar macrophages may be an important source of pulmonary TSG-6 required for HA remodeling. The formation of HC-modified HA had a minor role in the onset, severity, or resolution of experimental reversible ALI induced by respiratory infection with gram-negative bacteria.