The identification of genes with selective expression in specific organs or cell types provides an entry point for understanding biological processes that occur uniquely within a particular tissue. Using a subtraction approach designed to identify genes preferentially expressed in specific tissues, we have identified prostase, a human serine protease with prostate-restricted expression. The prostase cDNA encodes a putative 254-aa polypeptide with a conserved serine protease catalytic triad and an amino-terminal pre-propeptide sequence, indicating a potential secretory function. The genomic sequence comprises five exons and four introns and contains multiple copies of a chromosome 19q-specific minisatellite repeat. Northern analysis indicates that prostase mRNA is expressed in hormonally responsive normal and neoplastic prostate epithelial tissues, but not in prostate stromal constituents. Prostase shares 35% amino acid identity with prostate-specific antigen (PSA) and 78% identity with the porcine enamel matrix serine proteinase 1, an enzyme involved in enamel matrix degradation and with a putative role in the disruption of intercellular junctions. Radiation-hybrid-panel mapping localized prostase to chromosome 19q13, a region containing several other serine proteases, including protease M, pancreatic͞renal kallikrein hK1, and the prostate-specific kallikreins hK2 and hK3 (PSA). The sequence homology between prostase and other well-characterized serine proteases suggests several potential functional roles for the prostase protein that include the degradation of extracellular matrix and the activation of PSA and other proteases.

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Inflammatory stimulants such as bacterial endotoxin (lipopolysaccharide (LPS)) are known to induce tissue damage and injury partly through the induction of reactive oxygen species (ROS). Although it is recognized that the induction of ROS in macrophages byReactive oxygen species (ROS) 2 play a critical role in the regulation of inflammatory processes causing the oxidation of lipids and proteins and eventually leading to tissue damage and organ failure. The generation of ROS is modulated by two families of opposing enzymes, oxidative enzymes such as NADPH oxidase and antioxidative enzymes, including glutathione peroxidase, catalase, and superoxide dismutase. Bacterial products such as lipopolysaccharide (LPS) selectively induce the expression and activation of oxidative enzymes, while decreasing the expression of antioxidative enzymes (1, 2). Taken together, LPS challenge significantly contributes to the production of ROS and the pathogenesis of diverse inflammatory diseases.Most of the published studies regarding NADPH oxidase have been specifically focused on the regulation and activation of NOX-2, the enzymatic NADPH oxidase component primarily expressed in neutrophils (3, 4). NOX-2 protein is constitutively expressed and is not regulated transcriptionally (3). LPS challenge causes rapid translocation of the functional NOX-2 containing NADPH oxidase to the membrane complex, leading to its activation (3). In contrast, NOX-1, the primary NADPH oxidase in macrophages, can be both transcriptionally induced and post-transcriptionally activated by LPS. However, the molecular mechanism for LPS-induced expression and activation of NOX-1 is poorly defined. Based on studies done in other cell types (5, 6), it is conceivable that LPS may contribute to the activation of NOX-1 containing NADPH oxidase via the small GTPase Rac1 in macrophages (7). However, the detailed molecular mechanism underlying LPS-mediated activation of Rac1 in macrophages is not known.On the other hand, LPS treatment decreases the levels of nuclear receptor family transcription factors such as PPAR␣ and PGC-1, which are responsible for the sustained expression of antioxidative enzymes, including glutathione peroxidase and catalase (8 -11). Collectively, the LPS-triggered up-regulation of oxidative enzymes and concurrent down-regulation of antioxidases leads to the generation and accumulation of ROS and tissue damage.IRAK-1 is one of many intracellular signaling components downstream of the LPS receptor (TLR4) (12)(13)(14). A series of studies have revealed that IRAK-1 positively contributes to the activation of NFB, STAT1/3, and IRF5/7, while negatively regulating the activities of nuclear factor of activated T-cells and nuclear receptors (15)(16)(17)(18)(19)(20). Despite the prominent role that IRAK-1 plays within the TLR4 signaling pathway, its involve-

Subclinical levels of circulating endotoxin are associated with the pathogenesis of diverse human inflammatory diseases, by mildly inducing the expression of proinflammatory mediators. In this study, we examined the molecular mechanism responsible for the effect of low-dose LPS in macrophages. In contrast to high-dose LPS, which activates NF-κB and induces the robust expression of proinflammatory mediators, we observed that low-dose LPS failed to activate NF-κB. Instead, it selectively activated C/EBPδ and removed nuclear repressors, including peroxisome proliferator-activated receptor α and retinoic acid receptor α, enabling a mild and leaky expression of proinflammatory mediators. The effect of low-dose LPS required IRAK-1, which interacts with and acts upstream of IκB kinase ε to contribute to LPS-mediated induction of C/EBPδ and proinflammatory mediators. Additionally, mice fed a high-fat diet acquired elevated levels of endotoxin and proinflammatory mediators in an IRAK-1–dependent fashion. Taken together, these data reveal a distinct pathway preferentially used by low-dose endotoxin in initiating low-grade inflammation.

We expand the already large number of known trypsinogen nucleotide and amino acid sequences by presenting additional trypsinogen sequences from the tunicate (Boltenia villosa), the lamprey (Petromyzon marinus), the pufferfish (Fugu rubripes), and the frog (Xenopus laevis). The current array of known trypsinogen sequences now spans the entire vertebrate phylogeny. Phylogenetic analysis is made difficult by the presence of multiple isozymes within species and rates of evolution that vary highly between both species and isozymes. We nevertheless present a Fitch-Margoliash phylogeny constructed from pairwise distances. We employ this phylogeny as a vehicle for speculation on the evolution of the trypsinogen gene family as well as the general modes of evolution of multigene families. Unique attributes of the lamprey and tunicate trypsinogens are noted.