Transforming growth factor-beta activity in commercially available pasteurized cow milk provides protection against inflammation in mice.

Cow milk contains a large amount of an immunoregulatory cytokine, transforming growth factor-beta (TGFbeta). The present study investigated whether commercially available pasteurized cow milk retains TGFbeta activity both in vitro and in vivo. Some commercial cow milk increased TGFbeta/Smad-responsive reporter activity and induced Smad2 phosphorylation and the transcription of the TGFbeta/Smad target genes TGFbeta itself and Smad7 in vitro. Mice treated orally with 500 microL of cow milk containing TGFbeta (3 microg/L) daily for 2 wk had increased phosphorylation of Smad2 and TGFbeta and Smad7 mRNA expression in the intestine. These mice also had significantly greater serum TGFbeta concentrations than the mice treated orally with PBS. Furthermore, oral administration of 500 microL of cow milk containing TGFbeta (3 microg/L) daily for 2 wk before the induction of dextran sodium sulfate colitis and lipopolysaccharide-induced endotoxemia ameliorated tissue damage and mortality, respectively, in mice. These in vivo effects of cow milk were abrogated by the simultaneous administration of TGFbeta type I receptor kinase inhibitor with the cow milk, and they were not observed after the oral administration of cow's milk containing little TGFbeta. In humans, 1 oral challenge of 10 mL/kg cow milk containing TGFbeta (3 microg/L) increased the plasma TGFbeta concentrations at 4 h after the challenge. Thus, some commercially available pasteurized cow milk retains TGFbeta activity, which may be able to provide protection against experimental colitis and endotoxemia associated with increased intestinal and circulating TGFbeta levels.

Grape seed extract acting on astrocytes reveals neuronal protection against oxidative stress via interleukin-6-mediated mechanisms.

Grape polyphenols are known to protect neurons against oxidative stress. We used grape seed extract (GSE) from "Koshu" grapes (Vitis vinifera) containing a variety of polyphenols, and performed transcriptome analysis to determine the effects of GSE on primary cultures of astrocytes in the hippocampus. GSE upregulated various mRNAs for cytokines, among which interleukin-6 (IL-6) showed the biggest increase after treatment with GSE. The GSE-evoked increase in IL-6 mRNAs was confirmed by quantitative RT-PCR. We also detected IL-6 proteins by ELISA in the supernatant of GSE-treated astrocytes. We made an oxidative stress-induced neuronal cell death model in vitro using a neuron rich culture of the hippocampus. Treatment of the neurons with H(2)O(2) caused neuronal cell death in a time- and concentration-dependent manner. Exogenously applied IL-6 protected against the H(2)O(2)-induced neuronal cell death, which was mimicked by endogenous IL-6 produced by GSE-treated astrocytes. Taken together, GSE acting on astrocytes increased IL-6 production, which functions as a neuroprotective paracrine, could protect neuronal cells from death by oxidative stress.

Thymic stromal lymphopoietin secretion of synovial fibroblasts is positively and negatively regulated by Toll-like receptors/nuclear factor-kappaB pathway and interferon-gamma/dexamethasone.

Thymic stromal lymphopoietin (TSLP) is an interleukin (IL)-7-like cytokine produced by epithelial cells and triggers dendritic cell-mediated Th2 type allergic inflammatory responses. This study investigated whether Toll-like receptor (TLR) ligands, lipopolysaccharide (LPS) and poly-IC affect TSLP production in synovial fibroblasts. Enzyme-linked immunosorbent assay showed that LPS and poly-IC upregulated TSLP production in synovial fibroblasts obtained from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). In addition, we found that nuclear factor (NF)-kappaB inhibitor IMD-0354, dexamethasone, and interferon (IFN)-gamma inhibited the LPS- and poly-IC-induced TSLP production in RA and OA synovial fibroblasts. Thus, LPS and poly-IC can upregulate TSLP via a NF-kappaB pathway in synovial fibroblasts, which is downregulated by dexamethasone and interferon (IFN)-gamma. The current findings suggest that TSLP may be involved in the pathophysiology of inflammatory arthritis as well as allergic disease.

A possible role for TSLP in inflammatory arthritis.

Thymic stromal lymphopoietin (TSLP) is an IL-7-like cytokine that triggers dendritic cell-mediated Th2-type inflammatory responses and is considered as a master switch for allergic inflammation. In this study, we found increased levels of TSLP and, also TNF-alpha as previously reported, in synovial fluid specimens derived from patients with rheumatoid arthritis (RA) when compared with those from patients with osteoarthritis (OA). In addition, TNF-alpha up-regulated TSLP expression in RA- and OA-derived synovial fibroblasts, which was inhibited by IFN-gamma. Furthermore, anti-TSLP neutralizing antibody ameliorated a TNF-alpha-dependent experimental arthritis induced by anti-type II collagen antibody in mice. Collectively, these results suggest that TSLP, as a downstream molecule of TNF-alpha, may be involved in the pathophysiology of inflammatory arthritis. TSLP might thus play a role not only in allergic diseases but also in inflammatory arthritis such as RA.