Neprilysin Is Identical to Skin Fibroblast Elastase

Abstract

Although human skin fibroblast (HSF) elastase has been characterized as a membrane-bound metalloproteinase, little is known about its structure, amino acid sequence, and encoding gene. As there are similarities in the molecular weights and inhibitory profiles of HSF elastase and neprilysin (neutral endopeptidase 24.11 (NEP)), in this study we tested the hypothesis that they are identical using immunoprecipitation and transfection methods. An immunoprecipitation study demonstrated that HSF elastase activity co-immunoprecipitated with anti-NEP in lysates of cultured HSF. Transfection of an NEP cDNA expression vector into COS-1 cells elicited the expression of HSF elastase and NEP activities in the transfected cells. These findings strongly suggest that HSF elastase is identical to NEP, which functions mainly in neuron-associated cells to degrade neuropeptides. Analysis of the expression pattern of NEP revealed that its expression was remarkably up-regulated at the gene, protein, and enzymatic activity levels during the replicative senescence of cultured HSF. Further, the activity of NEP was markedly enhanced in a pattern similar to elastase activity during the intrinsic aging of mouse skin, in UVA-exposed HSF as well as in HSF treated with conditioned medium from UVBexposed human keratinocytes. Analysis of the cytokine profile for the stimulation of NEP and HSF elastase activities in HSF demonstrated that among the 11 cytokines tested, IL-1␣, IL-1␤, IL-6, IL-8, and GM-CSF had the potential to significantly stimulate both activities similarly, again supporting the identity of HSF elastase and NEP.Cumulative exposure to sunlight elicits the formation of wrinkles, which are associated with marked decreases in skin elasticity (1-3). We demonstrated previously that skin elasticity is remarkably diminished in an early phase of long term UV irradiation at a dose of less than 1 minimal erythemal dose (MED), which is accompanied by degeneration of the elastic fiber network (consisting of premature oxytalan, elaunin fibers, and mature elastic fibers) (1, 2). We also reported that elastase activity is gradually and markedly increased in the wrinkling process prior to the onset of wrinkle formation in UVB-exposed hairless mouse skin (4), which suggests the deep involvement of elastases in the damage of the elastic fiber network. The evidence that the exposure of animal skin to UVB at less than a suberythemal dose can cause wrinkles, despite the lack of inflammatory cell infiltration (5), led us to speculate that skin fibroblast elastase is mainly responsible for the degradation of elastic fibers. While characterizing the elastase-like enzyme derived from skin fibroblasts, we found that fibroblast elastase, which exhibits the characteristics of a metalloproteinase, is remarkably inhibited by metalloproteinase inhibitors but not by other inhibitors, which indicates that the fibroblast elastase belongs to the metalloproteinase family. To determine the contribution of fibroblast elastase activity to the deterioration of elastins ...

Tumoral CD10 expression correlates with high-grade histology and increases risk of recurrence in patients with stage I lung adenocarcinoma

“…In addition to the peptidase activity of CD10, 10,11,31 it also has elastase activity that degrades elastic fibers. 32 One possibility is that the elastase activity of CD10 may facilitate tumor invasiveness, thereby degrading elastic fibers in the lung parenchyma. Additionally, Maguer-Satta et al suggested that upregulation of CD10 enzymatic activity may inhibit epithelial differentiation of stem cells into mature cells or maintain cancer stem cells by cleaving peptides for differentiating signaling.…”

The Role of Neprilysin in Regulating the Hair Cycle

“…NEP can degrade a wide variety of bioactive peptides, for example enkephalins [22], bradykinin [23], neurotensin, substance P [23], [24], CGRP [25], natriuretic peptide [26], fMet-Leu-Phe [27], endothelin [26], [28], and galanin [29]. We previously showed that NEP also has elastase activity and plays important roles during intrinsic and UV-induced skin aging [18]. We now report the role of NEP in regulating the hair cycle.…”

“…Previously we determined that NEP has an elastin degrading activity [18]. It wouldn’t be a surprise if elastin, which is a component of the ECM, has some involvement in hair cycle control, because the hair cycle is considered as a kind of process of tissue remodeling.…”

“…However, only a few matrix degrading enzymes have been reported to be associated with the hair cycle so far, such as type IV collagenase [16], matrix metalloproteinase (MMP)-2 and TIMP-1 [1], [17]. Since we previously identified neprilysin (NEP) as dermal fibroblast elastase [18], we focused on the potential role of NEP in the regulation of the hair cycle.…”

Hypoxia increases membrane metallo-endopeptidase expression in a novel lung cancer ex vivo model – role of tumor stroma cells

“…It also possesses elastase activity [48]. MME is a membrane-bound protein, however, as was recently shown, MME can be released to the microenvironment of cells in exosomes [49].…”