Proteinase inhibitor 6 (PI-6) expression in human skin: induction of PI-6 and a PI-6/proteinase complex during keratinocyte differentiation

Korean Red Ginseng Up-regulates C21-Steroid Hormone Metabolism via Cyp11a1 Gene in Senescent Rat Testes

Ginseng (Panax ginseng Meyer) has been shown to have anti-aging effects in animal and clinical studies. However, the molecular mechanisms by which ginseng exerts these effects remain unknown. Here, the anti-aging effect of Korean red ginseng (KRG) in rat testes was examined by system biology analysis. KRG water extract prepared in feed pellets was administered orally into 12 month old rats for 4 months, and gene expression in testes was determined by microarray analysis. Microarray analysis identified 33 genes that significantly changed. Compared to the 2 month old young rats, 13 genes (Rps9, Cyp11a1, RT1-A2, LOC365778, Sv2b, RGD1565959, RGD1304748, etc.) were up-regulated and 20 genes (RT1-Db1, Cldn5, Svs5, Degs1, Vdac3, Hbb, LOC684355, Svs5, Tmem97, Orai1, Insl3, LOC497959, etc.) were down-regulated by KRG in the older rats. Ingenuity Pathway Analysis of untreated aged rats versus aged rats treated with KRG showed that the affected most was Cyp11a1, responsible for C21-steroid hormone metabolism, and the top molecular and cellular functions are organ morphology and reproductive system development and function. When genes in young rat were compared with those in the aged rat, sperm capacitation related genes were down-regulated in the old rat. However, when genes in the old rat were compared with those in the old rat treated with KRG, KRG treatment up-regulated C21-steroid hormone metabolism. Taken together, Cyp11a1 expression is decreased in the aged rat, however, it is up-regulated by KRG suggesting that KRG seems enhance testes function via Cyp11a1.

Engineered human skin substitutes undergo large-scale genomic reprogramming and normal skin-like maturation after transplantation to athymic mice

Bioengineered skin substitutes can facilitate wound closure in severely burned patients, but deficiencies limit their outcomes compared with native skin autografts. To identify gene programs associated with their in vivo capabilities and limitations, we extended previous gene expression profile analyses to now compare engineered skin after in vivo grafting with both in vitro maturation and normal human skin. Cultured skin substitutes were grafted on full-thickness wounds in athymic mice, and biopsy samples for microarray analyses were collected at multiple in vitro and in vivo time points. Over 10,000 transcripts exhibited large-scale expression pattern differences during in vitro and in vivo maturation. Using hierarchical clustering, 11 different expression profile clusters were partitioned on the basis of differential sample type and temporal stage-specific activation or repression. Analyses show that the wound environment exerts a massive influence on gene expression in skin substitutes. For example, in vivo-healed skin substitutes gained the expression of many native skin-expressed genes, including those associated with epidermal barrier and multiple categories of cell-cell and cell-basement membrane adhesion. In contrast, immunological, trichogenic, and endothelial gene programs were largely lacking. These analyses suggest important areas for guiding further improvement of engineered skin for both increased homology with native skin and enhanced wound healing.

Expression of serpinb6 serpins in germ and somatic cells of mouse gonads

The serpin superfamily of serine protease inhibitors is implicated in the regulation of numerous physiological processes. In mice, Spi3/Serpinb6 has a broad tissue distribution. We have investigated the expression of Serpinb6 family members in embryonic and adult gonads. In male and female mice, Spi3/Serpinb6 and NK13/Serpinb6b were expressed in developing gonads and in both somatic and germ cells of adult gonads. By contrast, gonadal expression of Spi3C/Serpinb6c was sexually dimorphic and restricted to male germ cells and female somatic cells. These observations raise the question of the possible role(s) of the Serpinb6 family members in gonad development, gametogenesis, and/or fertilization.

Expression of cathepsin L and its inhibitor hurpin in inflammatory and neoplastic skin diseases

Cathepsin (Cat) L is an important lysosomal proteinase involved in a variety of cellular functions including intracellular protein turnover, epidermal homeostasis and hair development. Hurpin (serpinB13) is a cross-class specific serine protease inhibitor of Cat L. We have analysed the expression and localization of Cat L and hurpin in various inflammatory and neoplastic diseases by immunohistochemistry. Whereas Cat L expression in normal skin was below detection limit, immunoreactivity was detected in chronic inflammatory dermatoses. The highest expression of Cat L was found in psoriasis, atopic eczema and squamous cell carcinoma (SCC) samples. Samples of Lupus erythematosus, folliculitis, acne inversa, chronic leg ulcers and pyoderma gangrenosum demonstrated similar but lower expression for Cat L. In malignant cells of SCC, basal cell carcinoma and malignant melanoma, characteristic staining patterns were observed for Cat L, with more abundant expression at the periphery of the tumor. Expanding our previous work, we found that the expression of hurpin was confined mainly to the basal layer in normal skin samples, whereas hurpin was overexpressed and redistributed in diseased skin. The localization of hurpin in dermatoses and neoplasias differed from that in normal skin in that the highest expression was found in the outermost layers of the granular and upper spinous layers. Similarly to Cat L, the highest expression for hurpin was found in psoriasis and SCC. The results presented here summarize for the first time the expression of the protease Cat L and its inhibitor hurpin in a broad spectrum of skin diseases.

Wounding activates p38 map kinase and activation transcription factor 3 in leading keratinocytes

Quiescent epidermis anchors to laminin 5 in the basement membrane via integrin alpha6beta4. Wounding elevates expression of laminin 5, generating leading keratinocytes (LKs) that migrate via beta1 integrins. Laminin 5 was evaluated as a regulator of cell signaling, and mRNA and protein expression in LKs. An in vitro wound model was developed based on suspension and re-adhesion of quiescent human keratinocytes (HKs). DNA microarrays identified multiple mRNAs elevated 1.5 hours after suspension and re-adhesion including activation transcription factor 3 (ATF3). In vitro and in vivo, levels of ATF3 protein elevate in nuclei of LKs, but not in nuclei of the following cells, 2 hours after suspension or wounding but decline by 12-18 hours post injury. Significantly, null defects in laminin 5 or integrin beta4 that inhibit anchorage chronically elevate ATF3 in vivo. This suggests that adhesion to laminin 5, but not other ligands, suppresses activation. On suspension, ATF3 and other transcripts in the microarrays are elevated by phosphorylated p38 mitogen-activated protein kinase (P-p38), a stress kinase that regulates mRNA and cell motility. Inhibition of P-p38 with SB203580 prevents phosphorylation of ATF2, a transcription factor for ATF3 in LKs. Re-adhesion to laminin 5 via alpha6beta4 dephosphorylates P-p38 and suppresses ATF3 protein relative to cells in suspension. Thus, wounding of quiescent HKs disrupts laminin 5 adhesion to activate p38, generating mRNA transcripts that define LKs. Adhesion to deposits of laminin 5 via alpha6beta4 suppresses P-p38 and activation mRNAs including ATF3. Defects in laminin 5 and alpha6beta4 sustain P-p38 with probable pathological effects on transcription and migration.

Intracellular serpin SERPINB6 (PI6) is abundantly expressed by human mast cells and forms complexes with beta-tryptase monomers

SERPINB6 (PI6) is a member of the intracellular serine protease inhibitors (serpins). Previous studies showed that SERPINB6 is localized mainly in the cytoplasm of endothelial cells, some epithelial cells, monocytes, and neutrophils. In these cells SERPINB6 is thought to prevent cellular damage by scavenging leaking lysosomal proteases. We show here, using novel, well-defined monoclonal antibodies, that SERPINB6 is abundantly expressed by mast cells in all organs and by the human mast cell line HMC-1. Gel filtration experiments revealed that the latter cells contain a high-molecular-weight form of SERPINB6, which consists of sodium dodecyl sulfate (SDS)-stable complexes of this inhibitor with monomeric beta-tryptase. Expression of SERPINB6 by mast cells was compared with those of tryptase and CD117 (c-kit) in biopsies from patients with different forms of mast cell disease. In all cases the lesional mast cells expressed SERPINB6, and, in diffuse cutaneous mastocytosis and mastocytoma, SERPINB6 was expressed by a substantially higher number of mast cells when compared with tryptase. In conclusion, SERPINB6 is abundantly expressed by normal mast cells and by mast cells in mastocytoma lesions. We suggest that in mast cells, SERPINB6 serves to regulate the activity of endogenous beta-tryptase in the cytoplasm.

Regulation of trespin expression by modulators of cell growth, differentiation, and apoptosis in prostatic epithelial cells

We recently identified a novel rat ov-serpin, Trespin, which inhibits the trypsin-like serine proteinase plasmin and is expressed in several tissues, including prostate. In this report Trespin expression was studied in prostatic cell lines, NRP-152, NRP-154, and DP-153, derived from the Lobund-Wistar rat. Northern blots revealed Trespin mRNA is expressed in NRP-152 and DP-153 basal epithelial cell lines but not in the luminal line, NRP-154. Similarly, Trespin levels drop >30-fold following transdifferentiation of NRP-152 cells toward a luminal variant, further suggesting Trespin expression is specific for basal prostatic epithelial cells. Trespin expression in NRP-152 cells is up-regulated by dexamethasone (Dex) and insulin-like growth factor-I (IGF-I), each of which stimulate growth and prevent differentiation and apoptosis. However, Dex (alone) facilitates loss of Trespin by TGF-beta, yet enhances the ability of LR(3)-IGF-I to reverse such loss, similar to the pattern of apoptosis induced by TGF-beta. Likewise, several apoptosis inducers markedly decrease Trespin mRNA levels. HEK293 cells stably overexpressing Trespin display increased cell proliferation and partial resistance to growth inhibition and phosphorylation of c-Jun induced by the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA). Together these data strongly suggest that Trespin has critical functions tied to the regulation of growth, differentiation, and apoptosis of prostatic epithelial cells.

The intracellular granzyme B inhibitor, proteinase inhibitor 9, is up-regulated during accessory cell maturation and effector cell degranulation, and its overexpression enhances CTL potency

Granzyme B (grB) is a serine proteinase released by cytotoxic lymphocytes (CLs) to kill abnormal cells. GrB-mediated apoptotic pathways are conserved in nucleated cells; hence, CLs require mechanisms to protect against ectopic or misdirected grB. The nucleocytoplasmic serpin, proteinase inhibitor 9 (PI-9), is a potent inhibitor of grB that protects cells from grB-mediated apoptosis in model systems. Here we show that PI-9 is present in CD4(+) cells, CD8(+) T cells, NK cells, and at lower levels in B cells and myeloid cells. PI-9 is up-regulated in response to grB production and degranulation, and associates with grB-containing granules in activated CTLs and NK cells. Intracellular complexes of PI-9 and grB are evident in NK cells, and overexpression of PI-9 enhances CTL potency, suggesting that cytoplasmic grB, which may threaten CL viability, is rapidly inactivated by PI-9. Because dendritic cells (DCs) acquire characteristics similar to those of target cells to activate naive CD8(+) T cells and therefore may also require protection against grB, we investigated the expression of PI-9 in DCs. PI-9 is evident in thymic DCs (CD3(-), CD4(+), CD8(-), CD45(+)), tonsillar DCs, and DC subsets purified from peripheral blood (CD16(+) monocytes and CD123(+) plasmacytoid DCs). Furthermore, PI-9 is expressed in monocyte-derived DCs and is up-regulated upon TNF-alpha-induced maturation of monocyte-derived DCs. In conclusion, the presence and subcellular localization of PI-9 in leukocytes and DCs are consistent with a protective role against ectopic or misdirected grB during an immune response.

Distribution of the human intracellular serpin protease inhibitor 8 in human tissues

Ovalbumin-like serine protease inhibitors are mainly localized intracellularly and their in vivo functions are largely unknown. To elucidate their physiological role(s), we studied the expression of one of these inhibitors, protease inhibitor 8 (PI-8), in normal human tissues by immunohistochemistry using a PI-8-specific monoclonal antibody. PI-8 was strongly expressed in the nuclei of squamous epithelium of mouth, pharynx, esophagus, and epidermis, and by the epithelial layer of skin appendages, particularly by more differentiated epithelial cells. PI-8 was also expressed by monocytes and by neuroendocrine cells in the pituitary gland, pancreas, and digestive tract. Monocytes showed nuclear and cytoplasmic localization of PI-8, whereas neuroendocrine cells showed only cytoplasmic staining. In vitro nuclear localization of PI-8 was confirmed by confocal analysis using serpin-transfected HeLa cells. Furthermore, mutation of the P(1) residue did not affect the subcellular distribution pattern of PI-8, indicating that its nuclear localization is independent of the interaction with its target protease. We conclude that PI-8 has a unique distribution pattern in human tissues compared to the distribution patterns of other intracellular serpins. Additional studies must be performed to elucidate its physiological role.

Comparison of human chromosome 6p25 with mouse chromosome 13 reveals a greatly expanded ov-serpin gene repertoire in the mouse

Ov-serpins are intracellular proteinase inhibitors implicated in the regulation of tumor progression, inflammation, and cell death. The 13 human ov-serpin genes are clustered at 6p25 (3 genes) and 18q21 (10 genes), and share common structures. We show here that a 1-Mb region on mouse chromosome 13 contains at least 15 ov-serpin genes compared with the three ov-serpin genes within 0.35 Mb at human 6p25 (SERPINB1 (MNEI), SERPINB6 (PI-6), SER-PINB9 (PI-9)). The mouse serpins have characteristics of functional inhibitors and fall into three groups on the basis of similarity to MNEI, PI-6, or PI-9. The genes map between the mouse orthologs of the Werner helicase interacting protein and NAD(P)H menadioine oxidoreductase 2 genes, in a region that contains the markers D13Mit136 and D13Mit116. They have the seven-exon structure typical of human 6p25 ov-serpin genes, with identical intron phasing. Most show restricted patterns of expression, with common sites of synthesis being the placenta and immune tissue. Compared with human, this larger mouse serpin repertoire probably reflects the need to regulate a larger proteinase repertoire arising from differing evolutionary pressures on the reproductive and immune systems.

Accelerated skin wound healing in plasminogen activator inhibitor-1-deficient mice

Components of the fibrinolytic system have been implicated in cell migratory events associated with tissue remodeling. Studies in plasminogen-deficient mice (PG(-/-)) indicated that skin wound healing is impaired, but is resolved with an additional fibrinogen deficiency. Plasminogen activator inhibitor-1 (PAI-1) expression by keratinocytes has been identified shortly after wound injury. PAI-1 expression could affect wound healing by regulating the fibrinolytic environment of the wounded area, as well as influencing events associated with cell attachment and detachment through interactions with matrix proteins. The present study directly assesses PAI-1 involvement in skin wound healing through analyses of a dermal biopsy punch model in PAI-1-deficient (PAI-1(-/-) mice. While the cellular events associated with the healing process are similar between wild-type (WT) and PAI-1(-/-) mice, the rate of wound closure is significantly accelerated in PAI-1(-/-) mice.

The spectrum of pathogenic mutations in SPINK5 in 19 families with Netherton syndrome: implications for mutation detection and first case of prenatal diagnosis

The Comèl-Netherton syndrome is an autosomal recessive multisystemic disorder characterized by localized or generalized congenital ichthyosis, hair shaft abnormalities, immune deficiency, and markedly elevated IgE levels. Life-threatening complications during infancy include temperature and electrolyte imbalance, recurrent infections, and failure to thrive. To study the clinical presentations of the Comèl-Netherton syndrome and its molecular cause, we ascertained 19 unrelated families of various ethnic backgrounds. Results of initial linkage studies mapped the Comèl-Netherton syndrome in 12 multiplex families to a 12 cM interval on 5q32, thus confirming genetic homogeneity of Comèl-Netherton syndrome across families of different origins. The Comèl-Netherton syndrome region harbors the SPINK5 gene, which encodes a multidomain serine protease inhibitor (LEKTI) predominantly expressed in epithelial and lymphoid tissues. Recently, recessive mutations in SPINK5 were identified in several Comèl-Netherton syndrome patients from consanguineous families. We used heteroduplex analysis followed by direct DNA sequencing to screen all 33 exons and flanking intronic sequences of SPINK5 in the affected individuals of our cohort. Mutation analysis revealed 17 distinct mutations, 15 of which were novel, segregating in 14 Comèl-Netherton syndrome families. The nucleotide changes included four non-sense mutations, eight small deletions or insertions leading to frameshift, and five splice site defects, all of which are expected to result in premature terminated or altered translation of SPINK5. Almost half of the mutations clustered between exons 2 and 8, including two recurrent mutations. Genotype-phenotype correlations suggested that homozygous nucleotide changes resulting in early truncation of LEKT1 are associated with a severe phenotype. For the first time, we used molecular data to perform prenatal testing, thus demonstrating the feasibility of molecular diagnosis in the Comèl-Netherton syndrome.

Evidence for intracellular cleavage of plasminogen activator inhibitor type 2 (PAI-2) in normal epidermal keratinocytes

Plasminogen activator inhibitor type 2 (PAI-2) is a serine proteinase inhibitor (serpin), present in high quantities in stratified squamous epithelia. Detergent extracts of human epidermis or cultured keratinocytes contain primarily active, nonglycosylated PAI-2. In keratinocytes, the vast majority of PAI-2 is retained within the cell, supporting the hypothesis that PAI-2 may serve specific intracellular function(s) through interaction with an unknown cytoplasmic proteinase. During interaction with the target proteinase, cleavage of PAI-2 within its reactive site loop leads to the formation of a more stable, "relaxed" conformation (PAI-2r). Using a monoclonal antibody specific for PAI-2r, we demonstrate here that PAI-2r is present in keratinocytes of the granular and basal layers of normal human epidermis. In addition, PAI-2r is detectable in cultured human epidermal keratinocytes, where it is concentrated in a detergent-insoluble fraction within differentiating cells. These data provide evidence for the presence of an endogenous, keratinocyte-derived proteinase that constitutively cleaves intracellular PAI-2 in normal human epidermal keratinocytes. Cleavage of PAI-2 by this proteinase may reflect specific intracellular action of PAI-2 in normal cells. Finally, we demonstrate that a commercially available anti-PAI-2 monoclonal antibody (#3750, American Diagnostica, Greenwich, CT), under native experimental conditions, preferentially recognizes the uncleaved, active form of PAI-2 and does not efficiently detect PAI-2r.

Cloning and characterization of hurpin (protease inhibitor 13): A new skin-specific, UV-repressible serine proteinase inhibitor of the ovalbumin serpin family

Epidermal keratinocytes are the primary target of the midrange ultraviolet part (UVB, 280-320 nm) of terrestrial sunlight. Analysis of the resulting UV response at the transcriptional level by differential display PCR identified a formerly unrecognized large group of repressed genes. Among those UV-repressible genes, a novel serine proteinase inhibitor (serpin) termed hurpin (HaCaT UV-repressible serpin) has been identified. The isolated full-length cDNAs harbour a 1176 bp open reading frame encoding a potential protein with 391 amino acid residues and a predicted molecular mass of approximately 44 kDa. The novel serpin has nearly 59 % amino acid identity with the squamous cell carcinoma antigen 1 (SCCA1) and squamous cell carcinoma antigen 2 (SCCA2). In addition, it displays all of the structural features unique to the ovalbumin family of serpins (ov-serpins). The amino acid sequence of the hinge region in the reactive site loop suggests that hurpin has the potential for protease inhibition. The putative reactive center P1-P1'residues were identified as Thr356-Ser357 by alignment with other ov-serpins. The physiological target protease is unknown and the in vitro translated hurpin does not form SDS-stable complexes with a variety of known serine proteases. Expression of hurpin is restricted to epidermal cells where two distinct transcripts of 3.0 and 3.4 kb are detectable. Furthermore, expression of hurpin appears to be related to the activation or proliferation state of keratinocytes, since hurpin transcripts are more abundant in immortalized keratinocytes (HaCaT) and in cultured normal human keratinocytes, compared to the expression in normal skin. Moreover, in psoriasis, a skin disease characterized by hyperproliferation of keratinocytes and responsive to therapeutic UV irradiation, overexpression of hurpin is noted in psoriatic skin lesions compared to non-lesional skin.

The Intracellular Serpin Proteinase Inhibitor 6 Is Expressed in Monocytes and Granulocytes and Is a Potent Inhibitor of the Azurophilic Granule Protease, Cathepsin G

The monocyte and granulocyte azurophilic granule proteinases elastase, proteinase 3, and cathepsin G are implicated in acute and chronic diseases thought to result from an imbalance between the secreted proteinase(s) and circulating serpins such as 1-proteinase inhibitor and 1-antichymotrypsin. We show here that the intracellular serpin, proteinase inhibitor 6 (PI-6), is present in monocytes, granulocytes, and myelomonocytic cell lines. In extracts from these cells, PI-6 bound an endogenous membrane-associated serine proteinase to form an sodium dodecyl sulfate (SDS)-stable complex. Using antibodies to urokinase, elastase, proteinase 3, or cathepsin G, we demonstrated that the complex contains cathepsin G. Native cathepsin G and recombinant PI-6 formed an SDS-stable complex in vitro similar in size to that observed in the extracts. Further kinetic analysis demonstrated that cathepsin G and PI-6 rapidly form a tight 1:1 complex (ka = 6.8 ± 0.2 × 106mol/L−1s−1 at 17°C;Ki = 9.2 ± 0.04 × 10−10 mol/L). We propose that PI-6 complements 1-proteinase inhibitor and 1-antichymotrypsin (which control extracellular proteolysis) by neutralizing cathepsin G that leaks into the cytoplasm of monocytes or granulocytes during biosynthesis or phagocytosis. Control of intracellular cathepsin G may be particularly important, because it has recently been shown to activate the proapoptotic proteinase, caspase-7.