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Palmoplantar keratoderma along with neuromuscular and metabolic phenotypes in Slurp1-deficient mice.

Adeyo O, Allan BB, Barnes RH, Goulbourne CN, Tatar A, Tu Y, Young LC, Weinstein MM, Tontonoz P, Fong LG, Beigneux AP, Young SG - J. Invest. Dermatol. (2014)

Bottom Line: SLURP1 is a secreted protein that is expressed highly in keratinocytes but has also been identified elsewhere (e.g., spinal cord neurons).In addition, Slurp1(-/-) mice exhibited reduced adiposity, protection from obesity on a high-fat diet, low plasma lipid levels, and a neuromuscular abnormality (hind-limb clasping).Initially, it was unclear whether the metabolic and neuromuscular phenotypes were due to Slurp1 deficiency, because we found that the targeted Slurp1 mutation reduced the expression of several neighboring genes (e.g., Slurp2, Lypd2).

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.

ABSTRACT
Mutations in SLURP1 cause mal de Meleda, a rare palmoplantar keratoderma (PPK). SLURP1 is a secreted protein that is expressed highly in keratinocytes but has also been identified elsewhere (e.g., spinal cord neurons). Here, we examined Slurp1-deficient mice (Slurp1(-/-)) created by replacing exon 2 with β-gal and neo cassettes. Slurp1(-/-) mice developed severe PPK characterized by increased keratinocyte proliferation, an accumulation of lipid droplets in the stratum corneum, and a water barrier defect. In addition, Slurp1(-/-) mice exhibited reduced adiposity, protection from obesity on a high-fat diet, low plasma lipid levels, and a neuromuscular abnormality (hind-limb clasping). Initially, it was unclear whether the metabolic and neuromuscular phenotypes were due to Slurp1 deficiency, because we found that the targeted Slurp1 mutation reduced the expression of several neighboring genes (e.g., Slurp2, Lypd2). We therefore created a new line of knockout mice (Slurp1X(-/-) mice) with a simple nonsense mutation in exon 2. The Slurp1X mutation did not reduce the expression of adjacent genes, but Slurp1X(-/-) mice exhibited all of the phenotypes observed in the original line of knockout mice. Thus, Slurp1 deficiency in mice elicits metabolic and neuromuscular abnormalities in addition to PPK.

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Immunochemical detection of SLURP1(A) Western blot of extracts of paw skin from wild-type (Slurp1+/+) and Slurp1−/− mice with an antibody against a mouse SLURP1 peptide. CHO cells transfected with a flag-tagged mouse SLURP1 expression vector were used as a control. SLURP1, like nearly all other Ly6 proteins, has an N-linked glycosylation site, and the two SLURP1 bands likely reflect glycosylated and nonglycosylated versions of the protein (Beigneux et al., 2008). The SLURP1 antibody did not cross-react with SLURP2. (B) The specificity of the human SLURP1 antibody (green) in these studies was assessed by immunocytochemistry. CHO-K1 cells were transiently transfected with an empty vector or an S-protein–tagged human SLURP1 expression vector. Cells that had been transiently transfected with the S-protein–tagged SLURP1 vector were identified with an S-protein–specific antibody (red). (C) Detection of SLURP1 (green) in human skin by immunohistochemistry with a human SLURP1 antibody. Keratin 14 (red) was used as a marker of basal keratinocytes; DNA was stained with DAPI (blue). Scale bars = 20 µm.
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Figure 2: Immunochemical detection of SLURP1(A) Western blot of extracts of paw skin from wild-type (Slurp1+/+) and Slurp1−/− mice with an antibody against a mouse SLURP1 peptide. CHO cells transfected with a flag-tagged mouse SLURP1 expression vector were used as a control. SLURP1, like nearly all other Ly6 proteins, has an N-linked glycosylation site, and the two SLURP1 bands likely reflect glycosylated and nonglycosylated versions of the protein (Beigneux et al., 2008). The SLURP1 antibody did not cross-react with SLURP2. (B) The specificity of the human SLURP1 antibody (green) in these studies was assessed by immunocytochemistry. CHO-K1 cells were transiently transfected with an empty vector or an S-protein–tagged human SLURP1 expression vector. Cells that had been transiently transfected with the S-protein–tagged SLURP1 vector were identified with an S-protein–specific antibody (red). (C) Detection of SLURP1 (green) in human skin by immunohistochemistry with a human SLURP1 antibody. Keratin 14 (red) was used as a marker of basal keratinocytes; DNA was stained with DAPI (blue). Scale bars = 20 µm.

Mentions: SLURP1 could be documented in the paw skin of wild-type mice but was absent in Slurp1−/− mice (Fig. 2 A). Our mouse SLURP1 antibodies were not useful for immunohistochemistry (and the lacZ cassette was not expressed), making it impossible to visualize SLURP1 expression in mouse skin. However, a human SLURP1-specific antibody detected SLURP1 in the suprabasal layers (including the spinous and granular layers) of human skin (Fig. 2 C), confirming earlier reports (Favre et al., 2007; Mastrangeli et al., 2003).


Palmoplantar keratoderma along with neuromuscular and metabolic phenotypes in Slurp1-deficient mice.

Adeyo O, Allan BB, Barnes RH, Goulbourne CN, Tatar A, Tu Y, Young LC, Weinstein MM, Tontonoz P, Fong LG, Beigneux AP, Young SG - J. Invest. Dermatol. (2014)

Immunochemical detection of SLURP1(A) Western blot of extracts of paw skin from wild-type (Slurp1+/+) and Slurp1−/− mice with an antibody against a mouse SLURP1 peptide. CHO cells transfected with a flag-tagged mouse SLURP1 expression vector were used as a control. SLURP1, like nearly all other Ly6 proteins, has an N-linked glycosylation site, and the two SLURP1 bands likely reflect glycosylated and nonglycosylated versions of the protein (Beigneux et al., 2008). The SLURP1 antibody did not cross-react with SLURP2. (B) The specificity of the human SLURP1 antibody (green) in these studies was assessed by immunocytochemistry. CHO-K1 cells were transiently transfected with an empty vector or an S-protein–tagged human SLURP1 expression vector. Cells that had been transiently transfected with the S-protein–tagged SLURP1 vector were identified with an S-protein–specific antibody (red). (C) Detection of SLURP1 (green) in human skin by immunohistochemistry with a human SLURP1 antibody. Keratin 14 (red) was used as a marker of basal keratinocytes; DNA was stained with DAPI (blue). Scale bars = 20 µm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4214150&req=5

Figure 2: Immunochemical detection of SLURP1(A) Western blot of extracts of paw skin from wild-type (Slurp1+/+) and Slurp1−/− mice with an antibody against a mouse SLURP1 peptide. CHO cells transfected with a flag-tagged mouse SLURP1 expression vector were used as a control. SLURP1, like nearly all other Ly6 proteins, has an N-linked glycosylation site, and the two SLURP1 bands likely reflect glycosylated and nonglycosylated versions of the protein (Beigneux et al., 2008). The SLURP1 antibody did not cross-react with SLURP2. (B) The specificity of the human SLURP1 antibody (green) in these studies was assessed by immunocytochemistry. CHO-K1 cells were transiently transfected with an empty vector or an S-protein–tagged human SLURP1 expression vector. Cells that had been transiently transfected with the S-protein–tagged SLURP1 vector were identified with an S-protein–specific antibody (red). (C) Detection of SLURP1 (green) in human skin by immunohistochemistry with a human SLURP1 antibody. Keratin 14 (red) was used as a marker of basal keratinocytes; DNA was stained with DAPI (blue). Scale bars = 20 µm.
Mentions: SLURP1 could be documented in the paw skin of wild-type mice but was absent in Slurp1−/− mice (Fig. 2 A). Our mouse SLURP1 antibodies were not useful for immunohistochemistry (and the lacZ cassette was not expressed), making it impossible to visualize SLURP1 expression in mouse skin. However, a human SLURP1-specific antibody detected SLURP1 in the suprabasal layers (including the spinous and granular layers) of human skin (Fig. 2 C), confirming earlier reports (Favre et al., 2007; Mastrangeli et al., 2003).

Bottom Line: SLURP1 is a secreted protein that is expressed highly in keratinocytes but has also been identified elsewhere (e.g., spinal cord neurons).In addition, Slurp1(-/-) mice exhibited reduced adiposity, protection from obesity on a high-fat diet, low plasma lipid levels, and a neuromuscular abnormality (hind-limb clasping).Initially, it was unclear whether the metabolic and neuromuscular phenotypes were due to Slurp1 deficiency, because we found that the targeted Slurp1 mutation reduced the expression of several neighboring genes (e.g., Slurp2, Lypd2).

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.

ABSTRACT
Mutations in SLURP1 cause mal de Meleda, a rare palmoplantar keratoderma (PPK). SLURP1 is a secreted protein that is expressed highly in keratinocytes but has also been identified elsewhere (e.g., spinal cord neurons). Here, we examined Slurp1-deficient mice (Slurp1(-/-)) created by replacing exon 2 with β-gal and neo cassettes. Slurp1(-/-) mice developed severe PPK characterized by increased keratinocyte proliferation, an accumulation of lipid droplets in the stratum corneum, and a water barrier defect. In addition, Slurp1(-/-) mice exhibited reduced adiposity, protection from obesity on a high-fat diet, low plasma lipid levels, and a neuromuscular abnormality (hind-limb clasping). Initially, it was unclear whether the metabolic and neuromuscular phenotypes were due to Slurp1 deficiency, because we found that the targeted Slurp1 mutation reduced the expression of several neighboring genes (e.g., Slurp2, Lypd2). We therefore created a new line of knockout mice (Slurp1X(-/-) mice) with a simple nonsense mutation in exon 2. The Slurp1X mutation did not reduce the expression of adjacent genes, but Slurp1X(-/-) mice exhibited all of the phenotypes observed in the original line of knockout mice. Thus, Slurp1 deficiency in mice elicits metabolic and neuromuscular abnormalities in addition to PPK.

Show MeSH
Related in: MedlinePlus