No abstract

To elucidate the association between killer cell immunoglobulin-like receptors (KIRs) and psoriasis vulgaris (PV), we typed 14 KIR genes in 96 Japanese cases and 50 healthy controls using PCR with sequence-specific primers (PCR-SSP). Here we report an interesting association between certain KIRs and Japanese cases with PV. The frequencies of KIR2DS1 and KIR2DL5 were significantly increased in PV cases compared with controls (KIR2DS1, 43 of 96 (45%) in cases vs 14 of 50 (28%) in controls; KIR2DL5, 46 of 96 (48%) in cases vs 15 of 50 (30%) in controls, p<0.05 for both), and the frequency of carriage of at least one presumed "B" haplotype, inferred from patterns including KIR2DL2, KIR2DL5, and/or various combinations of activating KIRs, was also statistically increased in the PV cases (53 of 96 (55%) in cases vs 18 of 50 (36%) in controls, p<0.04). The increase in KIR2DS1 has also been observed in psoriatic arthritis, another HLA-Cw6-associated disease (Martin et al, 2002). Accordingly, KIR2DS1 may be a common denominator of both diseases.

A novel bone-resorbing factor was cloned using an expression cloning technique, which involved a Xenopus oocyte expression system and an assay for osteoclast formation. A candidate clone was isolated from a BW5147 mouse T-lymphoma cell cDNA library. Sequencing analysis identified the factor as ␥-glutamyltranspeptidase (GGT), which is an enzyme involved in glutathione metabolism. The addition of purified GGT protein to mouse bone marrow culture effectively induced formation of osteoclasts. An antibody against GGT inhibited osteoclast formation but not the enzymatic activity. We also demonstrated that an inactive form of GGT, the enzymatic activity of which had been blocked by chemical modification with a specific inhibitor, acivicin, supported osteoclast formation. These results indicate that GGT acts on osteoclast formation independent of its own enzymatic activity. Furthermore, both native GGT and inactive GGT stimulated the expression of the receptor activator of nuclear factor-B ligand (RANKL) mRNA and protein from bone marrow stromal cells. This report is the first demonstration of a novel biological activity of GGT protein in a manner independent of its enzymatic activity.

The authors identified eight patients with Ullrich disease in whom collagen VI was present in the interstitium but was absent from the sarcolemma. By electron microscopy, collagen VI in the interstitium was never linked to the basal lamina. These findings suggest that in these patients it is not the total absence of collagen VI from the muscle but the failure of collagen VI to anchor the basal lamina to the interstitium that is the cause of Ullrich disease. Only one of the patients had a mutation in the collagen VI gene, suggesting that the primary abnormality in most of the patients involved some other molecules.

Gamma-aminobutyric acid (GABA) is an important neurotransmitter, but recent reports have revealed the expression of GABAergic components in peripheral, non-neural tissues. GABA administration induces natriuresis and lowers blood pressure, suggesting renal GABA targets. However, systematic evaluation of renal GABAergic components has not been reported. In this study, kidney cortices of Wistar-Kyoto rats (WKY) were used to assay for messenger RNAs of GABA-related molecules using RT-PCR. In WKY kidney cortex, GABAA receptor subunits, α1, β3, δ, ε and π, in addition to both types of GABAB receptors, R1 and R2, and GABAC receptor ρ1 and ρ2 subunit mRNAs were detected. Kidney cortex also expressed mRNAs of glutamate decarboxylase (GAD) 65, GAD67, 4-aminobutyrate aminotransferase and GABA transporter, GAT2. Western blot and/or immunohistochemistry were performed for those molecules detected by RT-PCR. By immunofluorescent observation, co-staining of α1, β3, and π subunits was observed mainly on the apical side of cortical tubules, and immunoblot of kidney protein precipitated with π subunit antibody revealed α1 and β3 subunit co-assembly. This is the first report of GABAA receptor π subunit in the kidney. In summary, unique set of GABA receptor subunits and subtypes were found in rat kidney cortex. As GABA producing enzymes, transporters and degrading enzyme were also detected, a possible existence of local renal GABAergic system with an autocrine/paracrine mechanism is suggested.