- Email: [email protected]
Expression of Neutrophil Gelatinase-Associated Lipocalin in Skin Epidermis
LETTER TO THE EDITOR
Expression of Neutrophil Gelatinase-Associated Lipocalin in Skin Epidermis Journal of Investigative Dermatology (2006) 126, 510–512. doi:10.1038/sj.jid.5700035; published online 29 December 2005
TO THE EDITOR Neutrophil gelatinase-associated lipocalin (NGAL), a member of the lipocalin family proteins, was originally identified as a 25-kDa protein that is covalently associated with the 92-kDa neutrophil gelatinase (gelatinase B, matrix metalloproteinase-9) (Kjeldsen et al., 1993; Bundgaard et al., 1994). Crystallographic analysis shows that the ligands of NGAL are a variety of bacterial ferric siderophores, which transport iron to bacteria (Goetz et al., 2002). By taking the iron away from bacteria, NGAL acts as a potent bacteriostatic agent under iron-limiting conditions (Flo et al., 2004). In addition, NGAL delivers iron to kidney cells, where it activates or represses iron-responsive genes, thereby playing an important role in mesenchymal–epithelial transition during the development of the mammalian nephron (Yang et al., 2002). We previously performed suppression subtractive hybridization to identify the genes related to keratinocyte differentiation, and found that NGAL was markedly induced by calcium in normal human epidermal keratinocytes cultured in vitro (Seo et al., 2004). To localize NGAL expression in the skin, we performed in situ hybridization. All skin samples were obtained with the written informed consent of donors, in accordance with the ethical committee approval process of Chungnam National University Hospital. The study was conducted according to the Declaration of Helsinki Principles. As shown in Figure 1a, the expression of NGAL, however, was not detected in normal skin tissue, inconsistent with Northern data from calcium-induced keratinocyte differentiation in vitro (Seo et al., 2004). In contrast, the
510
expression of NGAL was markedly increased at the upper granular layer of a psoriatic lesion, a prototype disease of disturbed keratinocyte differentiation. Particularly, the increased NGAL expression was restricted to the involved skin only, and there was no detectable signal in the uninvolved skin of psoriatic patients (Figure 1a, lower panel). Interestingly, NGAL expression was also detected in the inner root sheath of a hair follicle residing in the uninvolved portion of psoriatic skin (Figure 1a, open arrow), well matched to the result of Mallbris et al. (2002). Furthermore, we found that NGAL expression was increased in the infundibulum of a hair follicle (Figure 1a, closed arrow), suggesting that it has a potential role in the interface between organism and environment. Immunohistochemical staining also showed that NGAL was rarely detectable in normal skin, but highly increased in psoriatic lesions (Figure 1b). As it has been suggested that NGAL expression may be related to dysregulated keratinocyte differentiation (Mallbris et al., 2002), we further examined whether NGAL was expressed in atopic dermatitis, another skin disease showing abnormal keratinocyte differentiation. However, there was no increased expression of NGAL in atopic dermatitis (Figure 1b). RT-PCR and Western blot analyses repeatedly confirmed that NGAL expression was increased in psoriatic lesions at both the transcriptional and translational levels, but not in normal and atopic dermatitis skins (Figure 1c). Evidence indicates that lipopolysaccharide, a well-known pathogen-associated molecular pattern, induces NGAL secretion in macrophages cultured in vitro as well as in blood and
Abbreviation: NGAL, neutrophil gelatinase-associated lipocalin
peritoneal cells in vivo (Flo et al., 2004). This finding led us to assess whether the bacterial cell wall components could induce the expression of NGAL in epithelial cells. To this end, cultured normal human epidermal keratinocytes were exposed to the cell wall components of Gram-negative (lipopolysaccharide) and Gram-positive (lipoteichoic acid and peptidoglycan) bacteria. RT-PCR analysis clearly showed that all bacterial cell wall components increase NGAL mRNA level in cultured keratinocytes (Figure 2a). Immunocytochemistry analysis also confirmed that NGAL expression was markedly increased by several pathogen-associated molecular patterns (Figure 2b). Although we originally isolated NGAL as a calcium-induced gene in normal human epidermal keratinocytes cultured in vitro (Seo et al., 2004), the expression of NGAL in normal skin tissue was not detected by in situ hybridization and immunohistochemistry analyses, except for the inner root sheath and infundibulum of the hair follicle. These results reveal that the status of keratinocytes is somewhat different between in vivo and in vitro conditions, suggesting substantial changes in gene expression and/or alteration of a cell’s responses to extracellular stimuli. Interestingly, the expression pattern of several genes is very similar to that of NGAL, showing a difference between in vivo and in vitro conditions. For instance, a well-known psoriasis marker S100A7 (psoriasin) appears to have limited expression in normal tissue and a marked increase in cultured keratinocytes by calcium treatment (Martinsson et al., 2005). Another example includes human keratinocyte proline-rich protein, which shows remarkable induction in psoriatic lesions and cultured keratinocytes, however modest the expression in normal skin
Journal of Investigative Dermatology (2006), Volume 126
& 2005 The Society for Investigative Dermatology
SJ Seo et al. Expression of NGAL in Skin Epidermis
a
Normal
b
Psoriasis
Normal
Psoriasis
Atopy
Antisense
Normal Atopy
Psoriasis
NGAL
Sense
GAPDH
Normal Atopy Antisense NGAL Actin 100 m
Psoriasis
NGAL/actin ratio
c
NGAL/GAPDH ratio
100 m
Psoriasis
1.2 0.9
*
0.6 0.3 0
N
A
1.2
P
*
0.9 0.6 0.3 0
N
A
P
PGN
LTA
LPS
CTL
a
Calcium
Figure 1. Expression of NGAL in skin epidermis. (a) In situ hybridization. Sections (14 mm) of human normal skin and psoriatic lesions were hybridized with NGAL riboprobes. The NGAL-specific hybridization signals are strongly detected in the granular layer of the epidermis of psoriatic skin. In the hair follicle (lower panel, uninvolved region), NGAL is expressed at the inner root sheath (open arrow) and infundibulum (closed arrow). All experiments were performed with at least three different skin specimens with similar results. (b) Immunohistochemistry. Paraffin-embedded tissue sections of skin specimens were stained with antiNGAL antibody. Strong expression of NGAL is seen in the upper granular layer of psoriatic epidermis, but not in normal and atopic dermatitis. (c) Upper panel: RT-PCR analysis of NGAL expression in normal, atopic dermatitis and psoriasis skin tissues. Two micrograms of total RNAs extracted from the skin specimens were reverse transcribed with M-MLV reverse transcriptase and used for PCR amplification. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal control. Lower panel: Western blot analysis. Proteins extracted from skin specimens were separated on duplicate 15% polyacrylamide gels, and transferred onto nitrocellulose membranes. Each membrane was reacted with anti-NGAL antibody, and antiactin antibody as a loading control, respectively. All experiments were performed with at least three different skin specimens with similar results. Data are represented as the mean7standard error of mean (SEM) (*Po0.01 vs normal control). N: normal; A: atopy; P: psoriasis.
b LPS
CTL
NGAL
NGAL/GAPDH ratio
GAPDH LTA
0.8 0.6 0.4 0.2
* *
PGN
Calcium
* *
0
Figure 2. Induction of NGAL expression by bacterial cell wall components. (a) RT-PCR analysis. Normal human epidermal keratinocytes were treated with 10 mg/ml lipopolysaccharide (LPS), 10 mg/ml lipoteichoic acid (LTA), and 10 mg/ml peptidoglycan (PGN) for 24 h. Calcium (1.2 mM) was included as a positive control. Two micrograms of total RNAs were reverse transcribed with M-MLV reverse transcriptase and used for PCR amplification. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal control. The lower panel shows the result of triplicate measurements (mean values7standard error of mean (SEM), *Po0.01 vs control). (b) Immunocytochemistry. Cells were cultured on coverslips. After fixation and permeabilization, cells were stained with anti-NGAL antibody.
(Lee et al., 2005). Based on these results, we speculate that cultured keratinocytes reflect somehow the characteristics of psoriasis, in terms of gene
expression similarity. The precise characterization of cell status between in vivo and in vitro conditions will be an interesting further study.
It has been demonstrated that NGAL is expressed in a variety of normal and pathological human tissues, including the stomach, liver, kidney and colon (Cowland and Borregaard, 1997; Friedl et al., 1999). Furthermore, NGAL is expressed in most tissues normally exposed to microorganisms and its synthesis is induced in epithelial cells during inflammation, indicating either a microbicidal activity of NGAL or a role in the regulation of inflammation (Kjeldsen et al., 2000). This is supported by the finding that NGAL tightly binds bacterial catecholate-type ferric siderophores and is a potent bacteriostatic agent in iron-limiting conditions; secreted NGAL limits bacterial growth by sequestrating the iron-laden siderophore (Goetz et al., 2002; Flo et al., 2004). In our study, NGAL expression in cultured skin keratinocytes was convincingly increased by several bacterial cell wall components of Gram-negative (lipopolysaccharide) and Gram-positive www.jidonline.org
511
SJ Seo et al. Expression of NGAL in Skin Epidermis
(lipoteichoic acid and peptidoglycan) bacteria, raising the possibility that NGAL may have a broad-spectrum antimicrobial property and participate in the protection of skin against infection. This notion is partly supported by the fact that NGAL expression was increased in the involved psoriatic lesion, but not in atopic dermatitis; atopic dermatitis patients, in general, are more vulnerable to skin infection than psoriasis patients. The pattern of NGAL expression is in this respect similar to the expression of another antimicrobial protein hCAP-18 (Ong et al., 2002). Another interesting finding that supports the putative role of NGAL as a guardian for skin infection is the localization of NGAL expression in normal skin tissue. Consistent with the result of Mallbris et al. (2002), we found that NGAL expression is restricted to the hair follicle compartments in normal tissue (uninvolved portion of psoriasis in Figure 1a, lower panel), especially in the inner root sheath and infundibulum. As the infundibulum is the opening interface between organism and environment, we speculate that potent bacteriostatic agents are expressed in this site for effective protection of skin infection. The precise protective role of NGAL in skin epidermis, however, should be investigated further. Overall, we showed the distinct expression pattern of NGAL in skin epidermis, suggesting that NGAL may have multifunctional roles in the maintenance of skin homeostasis.
512
ACKNOWLEDGMENTS This study was supported by a grant from the Oriental Medicine R&D Project, Ministry of Health & Welfare, Republic of Korea (0405OD00-0815-0010).
Seong Jun Seo1, Ji-Young Ahn1, Chang-Kwun Hong1, Eun-Young Seo2, Kyung-Chae Kye2, Woong-Hee Lee2, Sang-Keun Lee3, Jong-Soon Lim3, Myong-Joon Hahn4, Lars Kjeldsen5, Niels Borregaard5, Chang Deok Kim2, Jang-Kyu Park2 and Jeung-Hoon Lee2 1
Department of Dermatology, College of Medicine, Chung Ang University Hospital, Seoul, Korea; 2Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea; 3Institute of Traditional Medicine and Bioscience, Daejeon University, Daejeon, Korea; 4Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea and 5Granulocyte Research Laboratory, Department of Hematology, Rigshospitalet, Copenhagen, Denmark. E-mail: [email protected] REFERENCES Bundgaard JR, Sengelov H, Borregaard N, Kjeldsen L (1994) Molecular cloning and expression of a cDNA encoding NGAL: a lipocalin expressed in human neutrophils. Biochem Biophys Res Commun 202:1468–75 Cowland JB, Borregaard N (1997) Molecular characterization and pattern of tissue expression of the gene for neutrophil gelatinaseassociated lipocalin from humans. Genomics 45:17–23 Flo TH, Smith KD, Sato S, Rodriguez DJ, Holmes MA, Strong RK et al. (2004) Lipocalin 2 mediates an innate immune response to bacterial infection by sequestrating iron. Nature 432:917–21 Friedl A, Stoesz SP, Buckley P, Gould MN (1999) Neutrophil gelatinase-associated lipocalin
Journal of Investigative Dermatology (2006), Volume 126
in normal and neoplastic human tissues. Cell type-specific pattern of expression. Histochem J 31:433–41 Goetz DH, Holmes MA, Borregaard N, Bluhm ME, Raymond KN, Strong RK (2002) The neutrophil lipocalin NGAL is a bacteriostatic agent that interferes with siderophore-mediated iron acquisition. Mol Cell 10:1033–43 Kjeldsen L, Cowland JB, Borregaard N (2000) Human neutrophil gelatinase-associated lipocalin and homologous proteins in rat and mouse. Biochim Biophys Acta 1482:272–83 Kjeldsen L, Johnsen AH, Sengelov H, Borregaard N (1993) Isolation and primary structure of NGAL, a novel protein associated with human neutrophil gelatinase. J Biol Chem 268:10425–32 Lee WH, Jang S, Lee JS, Lee Y, Seo EY, You KH et al. (2005) Molecular cloning and expression of human keratinocyte proline-rich protein (hKPRP), an epidermal marker isolated from calcium-induced differentiating keratinocytes. J Invest Dermatol 125: 995–1000 Mallbris L, O’Brien KP, Hulthen A, Sandstedt B, Cowland JB, Borregaard N et al. (2002) Neutrophil gelatinase-associated lipocalin is a marker for dysregulated keratinocyte differentiation in human skin. Exp Dermatol 11: 584–91 Martinsson H, Yhr M, Enerback C (2005) Expression patterns of S100A7 (psoriasin) and S100A9 (calgranulin-B) in keratinocyte differentiation. Exp Dermatol 14:161–8 Ong PY, Ohtake T, Brandt C, Strickland I, Boguniewicz M, Ganz T et al. (2002) Endogenous antimicrobial peptides and skin infections in atopic dermatitis. N Engl J Med 347:1151–60 Seo EY, Lee WH, Piao YJ, Kim KH, Lee KM, Ahn KS et al. (2004) Identification of calciuminducible genes in primary keratinocytes using suppression-subtractive hybridization. Exp Dermatol 13:163–9 Yang J, Goetz D, Li JY, Wang W, Mori K, Setlik D et al. (2002) An iron delivery path way mediated by a lipocalin. Mol Cell 10: 1045–56
Expression of Neutrophil Gelatinase-Associated Lipocalin in Skin Epidermis Journal of Investigative Dermatology (2006) 126, 510–512. doi:10.1038/sj.jid.5700035; published online 29 December 2005
TO THE EDITOR Neutrophil gelatinase-associated lipocalin (NGAL), a member of the lipocalin family proteins, was originally identified as a 25-kDa protein that is covalently associated with the 92-kDa neutrophil gelatinase (gelatinase B, matrix metalloproteinase-9) (Kjeldsen et al., 1993; Bundgaard et al., 1994). Crystallographic analysis shows that the ligands of NGAL are a variety of bacterial ferric siderophores, which transport iron to bacteria (Goetz et al., 2002). By taking the iron away from bacteria, NGAL acts as a potent bacteriostatic agent under iron-limiting conditions (Flo et al., 2004). In addition, NGAL delivers iron to kidney cells, where it activates or represses iron-responsive genes, thereby playing an important role in mesenchymal–epithelial transition during the development of the mammalian nephron (Yang et al., 2002). We previously performed suppression subtractive hybridization to identify the genes related to keratinocyte differentiation, and found that NGAL was markedly induced by calcium in normal human epidermal keratinocytes cultured in vitro (Seo et al., 2004). To localize NGAL expression in the skin, we performed in situ hybridization. All skin samples were obtained with the written informed consent of donors, in accordance with the ethical committee approval process of Chungnam National University Hospital. The study was conducted according to the Declaration of Helsinki Principles. As shown in Figure 1a, the expression of NGAL, however, was not detected in normal skin tissue, inconsistent with Northern data from calcium-induced keratinocyte differentiation in vitro (Seo et al., 2004). In contrast, the
510
expression of NGAL was markedly increased at the upper granular layer of a psoriatic lesion, a prototype disease of disturbed keratinocyte differentiation. Particularly, the increased NGAL expression was restricted to the involved skin only, and there was no detectable signal in the uninvolved skin of psoriatic patients (Figure 1a, lower panel). Interestingly, NGAL expression was also detected in the inner root sheath of a hair follicle residing in the uninvolved portion of psoriatic skin (Figure 1a, open arrow), well matched to the result of Mallbris et al. (2002). Furthermore, we found that NGAL expression was increased in the infundibulum of a hair follicle (Figure 1a, closed arrow), suggesting that it has a potential role in the interface between organism and environment. Immunohistochemical staining also showed that NGAL was rarely detectable in normal skin, but highly increased in psoriatic lesions (Figure 1b). As it has been suggested that NGAL expression may be related to dysregulated keratinocyte differentiation (Mallbris et al., 2002), we further examined whether NGAL was expressed in atopic dermatitis, another skin disease showing abnormal keratinocyte differentiation. However, there was no increased expression of NGAL in atopic dermatitis (Figure 1b). RT-PCR and Western blot analyses repeatedly confirmed that NGAL expression was increased in psoriatic lesions at both the transcriptional and translational levels, but not in normal and atopic dermatitis skins (Figure 1c). Evidence indicates that lipopolysaccharide, a well-known pathogen-associated molecular pattern, induces NGAL secretion in macrophages cultured in vitro as well as in blood and
Abbreviation: NGAL, neutrophil gelatinase-associated lipocalin
peritoneal cells in vivo (Flo et al., 2004). This finding led us to assess whether the bacterial cell wall components could induce the expression of NGAL in epithelial cells. To this end, cultured normal human epidermal keratinocytes were exposed to the cell wall components of Gram-negative (lipopolysaccharide) and Gram-positive (lipoteichoic acid and peptidoglycan) bacteria. RT-PCR analysis clearly showed that all bacterial cell wall components increase NGAL mRNA level in cultured keratinocytes (Figure 2a). Immunocytochemistry analysis also confirmed that NGAL expression was markedly increased by several pathogen-associated molecular patterns (Figure 2b). Although we originally isolated NGAL as a calcium-induced gene in normal human epidermal keratinocytes cultured in vitro (Seo et al., 2004), the expression of NGAL in normal skin tissue was not detected by in situ hybridization and immunohistochemistry analyses, except for the inner root sheath and infundibulum of the hair follicle. These results reveal that the status of keratinocytes is somewhat different between in vivo and in vitro conditions, suggesting substantial changes in gene expression and/or alteration of a cell’s responses to extracellular stimuli. Interestingly, the expression pattern of several genes is very similar to that of NGAL, showing a difference between in vivo and in vitro conditions. For instance, a well-known psoriasis marker S100A7 (psoriasin) appears to have limited expression in normal tissue and a marked increase in cultured keratinocytes by calcium treatment (Martinsson et al., 2005). Another example includes human keratinocyte proline-rich protein, which shows remarkable induction in psoriatic lesions and cultured keratinocytes, however modest the expression in normal skin
Journal of Investigative Dermatology (2006), Volume 126
& 2005 The Society for Investigative Dermatology
SJ Seo et al. Expression of NGAL in Skin Epidermis
a
Normal
b
Psoriasis
Normal
Psoriasis
Atopy
Antisense
Normal Atopy
Psoriasis
NGAL
Sense
GAPDH
Normal Atopy Antisense NGAL Actin 100 m
Psoriasis
NGAL/actin ratio
c
NGAL/GAPDH ratio
100 m
Psoriasis
1.2 0.9
*
0.6 0.3 0
N
A
1.2
P
*
0.9 0.6 0.3 0
N
A
P
PGN
LTA
LPS
CTL
a
Calcium
Figure 1. Expression of NGAL in skin epidermis. (a) In situ hybridization. Sections (14 mm) of human normal skin and psoriatic lesions were hybridized with NGAL riboprobes. The NGAL-specific hybridization signals are strongly detected in the granular layer of the epidermis of psoriatic skin. In the hair follicle (lower panel, uninvolved region), NGAL is expressed at the inner root sheath (open arrow) and infundibulum (closed arrow). All experiments were performed with at least three different skin specimens with similar results. (b) Immunohistochemistry. Paraffin-embedded tissue sections of skin specimens were stained with antiNGAL antibody. Strong expression of NGAL is seen in the upper granular layer of psoriatic epidermis, but not in normal and atopic dermatitis. (c) Upper panel: RT-PCR analysis of NGAL expression in normal, atopic dermatitis and psoriasis skin tissues. Two micrograms of total RNAs extracted from the skin specimens were reverse transcribed with M-MLV reverse transcriptase and used for PCR amplification. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal control. Lower panel: Western blot analysis. Proteins extracted from skin specimens were separated on duplicate 15% polyacrylamide gels, and transferred onto nitrocellulose membranes. Each membrane was reacted with anti-NGAL antibody, and antiactin antibody as a loading control, respectively. All experiments were performed with at least three different skin specimens with similar results. Data are represented as the mean7standard error of mean (SEM) (*Po0.01 vs normal control). N: normal; A: atopy; P: psoriasis.
b LPS
CTL
NGAL
NGAL/GAPDH ratio
GAPDH LTA
0.8 0.6 0.4 0.2
* *
PGN
Calcium
* *
0
Figure 2. Induction of NGAL expression by bacterial cell wall components. (a) RT-PCR analysis. Normal human epidermal keratinocytes were treated with 10 mg/ml lipopolysaccharide (LPS), 10 mg/ml lipoteichoic acid (LTA), and 10 mg/ml peptidoglycan (PGN) for 24 h. Calcium (1.2 mM) was included as a positive control. Two micrograms of total RNAs were reverse transcribed with M-MLV reverse transcriptase and used for PCR amplification. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal control. The lower panel shows the result of triplicate measurements (mean values7standard error of mean (SEM), *Po0.01 vs control). (b) Immunocytochemistry. Cells were cultured on coverslips. After fixation and permeabilization, cells were stained with anti-NGAL antibody.
(Lee et al., 2005). Based on these results, we speculate that cultured keratinocytes reflect somehow the characteristics of psoriasis, in terms of gene
expression similarity. The precise characterization of cell status between in vivo and in vitro conditions will be an interesting further study.
It has been demonstrated that NGAL is expressed in a variety of normal and pathological human tissues, including the stomach, liver, kidney and colon (Cowland and Borregaard, 1997; Friedl et al., 1999). Furthermore, NGAL is expressed in most tissues normally exposed to microorganisms and its synthesis is induced in epithelial cells during inflammation, indicating either a microbicidal activity of NGAL or a role in the regulation of inflammation (Kjeldsen et al., 2000). This is supported by the finding that NGAL tightly binds bacterial catecholate-type ferric siderophores and is a potent bacteriostatic agent in iron-limiting conditions; secreted NGAL limits bacterial growth by sequestrating the iron-laden siderophore (Goetz et al., 2002; Flo et al., 2004). In our study, NGAL expression in cultured skin keratinocytes was convincingly increased by several bacterial cell wall components of Gram-negative (lipopolysaccharide) and Gram-positive www.jidonline.org
511
SJ Seo et al. Expression of NGAL in Skin Epidermis
(lipoteichoic acid and peptidoglycan) bacteria, raising the possibility that NGAL may have a broad-spectrum antimicrobial property and participate in the protection of skin against infection. This notion is partly supported by the fact that NGAL expression was increased in the involved psoriatic lesion, but not in atopic dermatitis; atopic dermatitis patients, in general, are more vulnerable to skin infection than psoriasis patients. The pattern of NGAL expression is in this respect similar to the expression of another antimicrobial protein hCAP-18 (Ong et al., 2002). Another interesting finding that supports the putative role of NGAL as a guardian for skin infection is the localization of NGAL expression in normal skin tissue. Consistent with the result of Mallbris et al. (2002), we found that NGAL expression is restricted to the hair follicle compartments in normal tissue (uninvolved portion of psoriasis in Figure 1a, lower panel), especially in the inner root sheath and infundibulum. As the infundibulum is the opening interface between organism and environment, we speculate that potent bacteriostatic agents are expressed in this site for effective protection of skin infection. The precise protective role of NGAL in skin epidermis, however, should be investigated further. Overall, we showed the distinct expression pattern of NGAL in skin epidermis, suggesting that NGAL may have multifunctional roles in the maintenance of skin homeostasis.
512
ACKNOWLEDGMENTS This study was supported by a grant from the Oriental Medicine R&D Project, Ministry of Health & Welfare, Republic of Korea (0405OD00-0815-0010).
Seong Jun Seo1, Ji-Young Ahn1, Chang-Kwun Hong1, Eun-Young Seo2, Kyung-Chae Kye2, Woong-Hee Lee2, Sang-Keun Lee3, Jong-Soon Lim3, Myong-Joon Hahn4, Lars Kjeldsen5, Niels Borregaard5, Chang Deok Kim2, Jang-Kyu Park2 and Jeung-Hoon Lee2 1
Department of Dermatology, College of Medicine, Chung Ang University Hospital, Seoul, Korea; 2Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea; 3Institute of Traditional Medicine and Bioscience, Daejeon University, Daejeon, Korea; 4Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea and 5Granulocyte Research Laboratory, Department of Hematology, Rigshospitalet, Copenhagen, Denmark. E-mail: [email protected] REFERENCES Bundgaard JR, Sengelov H, Borregaard N, Kjeldsen L (1994) Molecular cloning and expression of a cDNA encoding NGAL: a lipocalin expressed in human neutrophils. Biochem Biophys Res Commun 202:1468–75 Cowland JB, Borregaard N (1997) Molecular characterization and pattern of tissue expression of the gene for neutrophil gelatinaseassociated lipocalin from humans. Genomics 45:17–23 Flo TH, Smith KD, Sato S, Rodriguez DJ, Holmes MA, Strong RK et al. (2004) Lipocalin 2 mediates an innate immune response to bacterial infection by sequestrating iron. Nature 432:917–21 Friedl A, Stoesz SP, Buckley P, Gould MN (1999) Neutrophil gelatinase-associated lipocalin
Journal of Investigative Dermatology (2006), Volume 126
in normal and neoplastic human tissues. Cell type-specific pattern of expression. Histochem J 31:433–41 Goetz DH, Holmes MA, Borregaard N, Bluhm ME, Raymond KN, Strong RK (2002) The neutrophil lipocalin NGAL is a bacteriostatic agent that interferes with siderophore-mediated iron acquisition. Mol Cell 10:1033–43 Kjeldsen L, Cowland JB, Borregaard N (2000) Human neutrophil gelatinase-associated lipocalin and homologous proteins in rat and mouse. Biochim Biophys Acta 1482:272–83 Kjeldsen L, Johnsen AH, Sengelov H, Borregaard N (1993) Isolation and primary structure of NGAL, a novel protein associated with human neutrophil gelatinase. J Biol Chem 268:10425–32 Lee WH, Jang S, Lee JS, Lee Y, Seo EY, You KH et al. (2005) Molecular cloning and expression of human keratinocyte proline-rich protein (hKPRP), an epidermal marker isolated from calcium-induced differentiating keratinocytes. J Invest Dermatol 125: 995–1000 Mallbris L, O’Brien KP, Hulthen A, Sandstedt B, Cowland JB, Borregaard N et al. (2002) Neutrophil gelatinase-associated lipocalin is a marker for dysregulated keratinocyte differentiation in human skin. Exp Dermatol 11: 584–91 Martinsson H, Yhr M, Enerback C (2005) Expression patterns of S100A7 (psoriasin) and S100A9 (calgranulin-B) in keratinocyte differentiation. Exp Dermatol 14:161–8 Ong PY, Ohtake T, Brandt C, Strickland I, Boguniewicz M, Ganz T et al. (2002) Endogenous antimicrobial peptides and skin infections in atopic dermatitis. N Engl J Med 347:1151–60 Seo EY, Lee WH, Piao YJ, Kim KH, Lee KM, Ahn KS et al. (2004) Identification of calciuminducible genes in primary keratinocytes using suppression-subtractive hybridization. Exp Dermatol 13:163–9 Yang J, Goetz D, Li JY, Wang W, Mori K, Setlik D et al. (2002) An iron delivery path way mediated by a lipocalin. Mol Cell 10: 1045–56