Generalized pustular psoriasis (GPP) is a rare inflammatory skin disease that can be life-threatening. Recently, it has been reported that familial GPP is caused by homozygous or compound heterozygous mutations of IL36RN. However, the majority of GPP cases are sporadic and it is controversial whether IL36RN mutations are a causative/predisposing factor for sporadic GPP. We searched for IL36RN mutations in two groups of GPP patients in the Japanese population in this study: GPP without psoriasis vulgaris (PV), and GPP with PV. Eleven cases of GPP without PV (GPP alone) and 20 cases of GPP accompanied by PV (GPP with PV) were analyzed. Surprisingly, 9 out of 11 cases of GPP alone had homozygous or compound heterozygous mutations in IL36RN. In contrast, only 2 of 20 cases of GPP with PV had compound heterozygous mutations in IL36RN. The two cases of GPP with PV who had compound heterozygous mutations in IL36RN are siblings, and both cases had PV-susceptible HLA-A*0206. We determined that GPP alone is a distinct subtype of GPP and is etiologically distinguished from GPP with PV, and that the majority of GPP alone is caused by deficiency of the interleukin-36 receptor antagonist due to IL36RN mutations.

Intestinal glucose uptake is mainly performed by the sodium-dependent glucose transporter, SGLT1. The transport activity of SGLT1 was markedly inhibited by green tea polyphenols, this inhibitory activity being most pronounced in polyphenols having galloyl residues such as epicatechin gallate (ECg) and epigallocatechin gallate (EGCg). Experiments using brush-border membrane vesicles obtained from the rabbit small intestine demonstrated that ECg inhibited SGLT1 in a competitive manner, although ECg itself was not transported via SGLT1. The present results suggest that tea polyphenols such as ECg interact with SGLT1 as antagonist-like molecules, possibly playing a role in controlling the dietary glucose uptake in the intestinal tract.

Some of the food-derived tripeptides with angiotensin converting enzyme (ACE)-inhibitory activity have been reported to be hypotensive after being orally administered. The mechanism for the intestinal transport of these tripeptides was studied by using monolayer-cultured human intestinal Caco-2 cells which express many enterocyte-like functions including the peptide transporter (PepT1)-mediated transport system. Val-Pro-Pro, an ACE-inhibitory peptide from fermented milk, was used as a model tripeptide. A significant amount of intact Val-Pro-Pro was transported across the Caco-2 cell monolayer. This transport was hardly inhibited by a competitive substrate for PepT1. Since no intact Val-Pro-Pro was detected in the cells, Val-Pro-Pro apically taken by Caco-2 cells via PepT1 was likely to have been quickly hydrolyzed by intracellular peptidases, producing free Val and Pro. These findings suggest that PepT1-mediated transport was not involved in the transepithelial transport of intact Val-Pro-Pro. Paracellular diffusion is suggested to have been the main mechanism for the transport of intact Val-Pro-Pro across the Caco-2 cell monolayer.

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Objective. To investigate the mechanism of the inhibitory action of hyaluronan (HA) on interleukin-1␤ (IL-1␤)-stimulated production of matrix metalloproteinases (MMPs) in human articular cartilage.Methods. IL-1␤ was added to normal and osteoarthritic (OA) human articular cartilage in explant culture to stimulate MMP production. Articular cartilage was incubated or preincubated with a clinically used form of 800-kd HA to assess its effect on IL-1␤-induced MMPs. Levels of secreted MMPs 1, 3, and 13 in conditioned media were detected by immunoblotting; intracellular MMP synthesis in chondrocytes was evaluated by immunofluorescence microscopy. Penetration of HA into cartilage tissue and its binding to CD44 were analyzed by fluorescence microscopy using fluoresceinated HA. Blocking experiments with anti-CD44 antibody were performed to investigate the mechanism of action of HA.Results. Treatment and pretreatment with 800-kd HA at 1 mg/ml resulted in significant suppression of IL-1␤-stimulated production of MMPs 1, 3, and 13 in normal and OA cartilage explant culture. Fluorescence histocytochemistry revealed that HA penetrated cartilage tissue and localized in the pericellular matrix around chondrocytes. HA-binding blocking experiments using anti-CD44 antibody demonstrated that the association of HA with chondrocytes was mediated by CD44. Preincubation with anti-CD44 antibody, which suppressed IL-1␤-stimulated MMPs, reversed the inhibitory effect of HA on MMP production that was induced by IL-1␤ in normal and OA cartilage.Conclusion. This study demonstrates that HA effectively inhibits IL-1␤-stimulated production of MMP-1, MMP-3, and MMP-13, which supports the clinical use of HA in the treatment of OA. The action of HA on IL-1␤ may involve direct interaction between HA and CD44 on chondrocytes.Osteoarthritis (OA) is the most prevalent disease of articular joints and is the major cause of disability in the elderly. Pathophysiologic changes occur in OA cartilage due to the excessive expression of cartilagedegrading proteinases, the resultant progressive breakdown of collagen fibers, and the degradation of proteoglycan, mainly aggrecan (1).Matrix metalloproteinases (MMPs) are zinccontaining, calcium-dependent proteinases, which collectively degrade all components of the extracellular matrix. MMPs are considered to be important in the chondrolytic processes that contribute to the degenerative changes in OA cartilage (2-4). Recent studies have identified the messenger RNA (mRNA) for some MMPs, such as MMP-1, in human OA cartilage (4,5), and other investigators have reported specific MMP proteins and collagenasemediated type II collagen degradation products (6,7). There is a consensus that these enzymes play a critical role in intrinsic chondrocyte-mediated degenerative changes of the cartilage matrix in OA. Proinflammatory cytokines such as interleukin-1 (IL-1) strongly stimulate the expression of MMPs by chondrocytes in arthritis (8).Hyaluronan (HA) is a major component of synovial fluid and cartilage matrix, and it play...

Long-term changes in structure of fish communities on coral reefs infested by the coralfeeding starfish Acanthasterplanci were determined using 20 mZ visual transects. We censused a living coral reef consisting mainly of staghorn Acropora spp. at Saluyama Bay and a dead coral reef with low structural complexlty of coral branches (about 2 yr after A. planci infestation) at Amitori Bay, Iriomote Island (Ryukyu Islands, Japan) in September 1984. Two yr later, we recensused the dead coral reef, which had changed into a flat plain of unstructured coral rubble ('rubble reef'). Mean numbers of species and individuals per transect severely decreased in the following order of reef types: (1) living reef (1984). (2) dead reef (1984), and (3) rubble reef (1986). Correlated with these decreases in numbers were several patterns: (1) coral-polyp feeders completely &sappeared on both dead and rubble reefs, probably due to absence of food; (2) numbers of resident species and individuals decreased on the dead reef, perhaps due to decrease in living space or shelter associated with the reduction in structural complexity of coral branches; and (3) numbers of species and individuals of both resident and visitor fishes declined on the unstructured rubble reef, likely due to shortage of living space and food.

Peroxisome proliferator-activated receptor (PPAR)-γ γ γ γ 2, a member of the nuclear hormone receptor superfamily, plays a key role in adipocyte differentiation. Its amino-terminal region carries a ligandindependent gene-activating function, AF-1, and is composed of activation as well as repression domains. We have found PPARγ γ γ γ 2 and its isoform, PPARγ γ γ γ 1, to be modified by small ubiquitin-related modifier (SUMO)-1 in vivo , at a lysine residue in the repression domain. In reporter assays, a sumoylation-defective K107R mutant of PPARγ γ γ γ 2 exhibited much stronger transactivation than the wild-type, comparable with that of a mutant deleted for the repression domain. A close inverse correlation was observed between the levels of sumoylation and transactivation by PPARγ γ γ γ 2, in analyses employing PPARγ γ γ γ 2 forms with mutations in the sumoylation motif and a dominantnegative mutant of the SUMO conjugating enzyme, Ubc9. Studies with phosphorylation-defective mutants suggested that phosphorylation at S112 of PPARγ γ γ γ 2 promotes K107 sumoylation, and this latter exerts the more potent repressive effects. The K107R mutant PPARγ γ γ γ 2, when infected into NIH3T3 cells with a viral vector, promoted differentiation into adipocytes more efficiently than the wild-type. These observations provide evidence that sumoylation is involved in negative regulation of the transactivating function of PPARγ γ γ γ 2.

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