Microfluidic skin chip with vasculature for recapitulating the immune response of the skin tissue.

There is a considerable need for cell-based in vitro skin models for studying dermatological diseases and testing cosmetic products, but current in vitro skin models lack physiological relevance compared to human skin tissue. For example, many dermatological disorders involve complex immune responses, but current skin models are not capable of recapitulating the phenomena. Previously, we reported development of a microfluidic skin chip with a vessel structure and vascular endothelial cells. In this study, we cocultured dermal fibroblasts and keratinocytes with vascular endothelial cells, human umbilical vascular endothelial cells. We verified the formation of a vascular endothelium in the presence of the dermis and epidermis layers by examining the expression of tissue-specific markers. As the vascular endothelium plays a critical role in the migration of leukocytes to inflammation sites, we incorporated leukocytes in the circulating media and attempted to mimic the migration of neutrophils in response to external stimuli. Increased secretion of cytokines and migration of neutrophils was observed when the skin chip was exposed to ultraviolet irradiation, showing that the microfluidic skin chip may be useful for studying the immune response of the human tissue.

Rhamnogalacturonan-I-Type Polysaccharide Purified from Broccoli Exerts Anti-Metastatic Activities Via Innate Immune Cell Activation.

To examine the anti-metastatic activities of polysaccharides in broccoli, purified polysaccharides (BCE-I, -II, and -III) were isolated by fractionation of broccoli enzyme extracts and subsequent ethanol precipitation. BCE-I mainly consisted of galactose and arabinose, whereas BCE-II mainly consisted of galacturonic acid and rhamnose, and BCE-III mainly consisted of rhamnose and galactose. Of the three fractions, stimulation of murine peritoneal macrophages by BCE-I showed the greatest enhancement of tumor necrosis factor-α, interleukin (IL)-12, and IL-6 secretion. In addition, intravenous (i.v.) administration of BCE-I enhanced the lethal activity of natural killer (NK) cells on YAC-1 tumor cells significantly and dose-dependently in an ex vivo experiment of NK cell activity. In an experimental model using lung metastasis of Colon26-M3.1 carcinoma cells, prophylactic i.v. and oral administration of BCE-I significantly and dose-dependently inhibited lung metastatic activity. Furthermore, the inhibitory activity of BCE-1 on lung metastasis partially disappeared when NK cell function was removed through treatment of rabbit anti-asialo GM1. These results indicated that BCE-I has potent antitumor metastatic activity, and that its anti-metastatic activity has relevance to the stimulation of NK and other immune cells.

Structural features of immunostimulatory polysaccharide purified from pectinase hydrolysate of barley leaf.

Four polysaccharide fractions were isolated from young barley leaves treated with or without pectinase followed by ethanol fractionation. Among the polysaccharide fractions, BLE-P isolated from pectinase digested with a high molecular weight had the most enhanced macrophage stimulatory activity, indicating that pectinase digestion of barley leaf is a useful method for enhancement of its activity. BLE-P was further purified by column chromatography to identify the chemical and structural properties. BLE-P-I eluted in void volume fraction showed potent macrophage stimulatory activity. Monosaccharide composition and linkage analysis indicated that at least three kinds of polysaccharide, that is, glucuronoarabinoxylan (GAX; 40-45%), rhamnogalacturonan-I (RG-I) with branching mainly involving a type II arabinogalactan (AG-II) side chain (30-35%), and linear glucan such as starch and cellulose (less than 10%) coexisted in BLE-P-I. Given the association with macrophage stimulatory activity, it is likely that the GAX and to the RG-I polysaccharide branched with an AG-II side chain may be important for expression of the activity in barley leaf.