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Toll-like receptor 3 activation is required for normal skin barrier repair following UV damage.

Borkowski AW, Kuo IH, Bernard JJ, Yoshida T, Williams MR, Hung NJ, Yu BD, Beck LA, Gallo RL - J. Invest. Dermatol. (2014)

Bottom Line: UV damage to the skin leads to the release of noncoding RNA (ncRNA) from necrotic keratinocytes that activates Toll-like receptor 3 (TLR3).This release of ncRNA triggers inflammation in the skin following UV damage.Combined, these data further validate the conclusion that recognition of endogenous RNA by TLR3 is an important step in the program of skin barrier repair.

View Article: PubMed Central - PubMed

Affiliation: Division of Dermatology, Department of Medicine, University of California, San Diego, La Jolla, California, USA.

ABSTRACT
UV damage to the skin leads to the release of noncoding RNA (ncRNA) from necrotic keratinocytes that activates Toll-like receptor 3 (TLR3). This release of ncRNA triggers inflammation in the skin following UV damage. Recently, TLR3 activation was also shown to aid wound repair and increase the expression of genes associated with permeability barrier repair. Here, we sought to test whether skin barrier repair after UVB damage is dependent on the activation of TLR3. We observed that multiple ncRNAs induced expression of skin barrier repair genes, that the TLR3 ligand Poly (I:C) also induced expression and function of tight junctions, and that the ncRNA U1 acts in a TLR3-dependent manner to induce expression of skin barrier repair genes. These observations were shown to have functional relevance as Tlr3-/- mice displayed a delay in skin barrier repair following UVB damage. Combined, these data further validate the conclusion that recognition of endogenous RNA by TLR3 is an important step in the program of skin barrier repair.

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Related in: MedlinePlus

U1 RNA stimulates skin barrier genes in a TLR3-dependent mannerTLR3 was silenced in normal human epidermal keratinocytes (NHEKs) for 48 hours before treatment with 1 μg/ml U1 RNA or 1 μg/ml Poly(I:C) for 24 hours. Real-time PCR was used to quantify (a) ABCA12, (b) GBA, (c) SMPD1, and (d) TNFα mRNA levels and fold change values are calculated relative to and normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression. Data are mean +/− SEM, n = 3, and are representative of at least three independent experiments. * = P < 0.05, ** = P < 0.01, *** = P < 0.001. Two-tailed t-test.
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Figure 3: U1 RNA stimulates skin barrier genes in a TLR3-dependent mannerTLR3 was silenced in normal human epidermal keratinocytes (NHEKs) for 48 hours before treatment with 1 μg/ml U1 RNA or 1 μg/ml Poly(I:C) for 24 hours. Real-time PCR was used to quantify (a) ABCA12, (b) GBA, (c) SMPD1, and (d) TNFα mRNA levels and fold change values are calculated relative to and normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression. Data are mean +/− SEM, n = 3, and are representative of at least three independent experiments. * = P < 0.05, ** = P < 0.01, *** = P < 0.001. Two-tailed t-test.

Mentions: U1 spliceosomal RNA (U1 RNA) is a noncoding, small nuclear RNA (snRNA) that is increased in UVB-treated keratinocytes and stimulates inflammation in human keratinocytes and mouse skin in a TLR3-dependent manner (Bernard et al. 2012). In order to determine the effects of U1 RNA and TLR3 activation on skin barrier genes, TLR3 was knocked down using small interfering RNA (siRNA) and NHEK were then treated with 1 μg/ml U1 RNA for 24 hours. U1 RNA caused a significant increase in transcripts of ABCA12, GBA, SMPD1 and TNFα, while the induction of these genes was significantly decreased in NHEK pretreated with TLR3 siRNA (Figure 3).


Toll-like receptor 3 activation is required for normal skin barrier repair following UV damage.

Borkowski AW, Kuo IH, Bernard JJ, Yoshida T, Williams MR, Hung NJ, Yu BD, Beck LA, Gallo RL - J. Invest. Dermatol. (2014)

U1 RNA stimulates skin barrier genes in a TLR3-dependent mannerTLR3 was silenced in normal human epidermal keratinocytes (NHEKs) for 48 hours before treatment with 1 μg/ml U1 RNA or 1 μg/ml Poly(I:C) for 24 hours. Real-time PCR was used to quantify (a) ABCA12, (b) GBA, (c) SMPD1, and (d) TNFα mRNA levels and fold change values are calculated relative to and normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression. Data are mean +/− SEM, n = 3, and are representative of at least three independent experiments. * = P < 0.05, ** = P < 0.01, *** = P < 0.001. Two-tailed t-test.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4289479&req=5

Figure 3: U1 RNA stimulates skin barrier genes in a TLR3-dependent mannerTLR3 was silenced in normal human epidermal keratinocytes (NHEKs) for 48 hours before treatment with 1 μg/ml U1 RNA or 1 μg/ml Poly(I:C) for 24 hours. Real-time PCR was used to quantify (a) ABCA12, (b) GBA, (c) SMPD1, and (d) TNFα mRNA levels and fold change values are calculated relative to and normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression. Data are mean +/− SEM, n = 3, and are representative of at least three independent experiments. * = P < 0.05, ** = P < 0.01, *** = P < 0.001. Two-tailed t-test.
Mentions: U1 spliceosomal RNA (U1 RNA) is a noncoding, small nuclear RNA (snRNA) that is increased in UVB-treated keratinocytes and stimulates inflammation in human keratinocytes and mouse skin in a TLR3-dependent manner (Bernard et al. 2012). In order to determine the effects of U1 RNA and TLR3 activation on skin barrier genes, TLR3 was knocked down using small interfering RNA (siRNA) and NHEK were then treated with 1 μg/ml U1 RNA for 24 hours. U1 RNA caused a significant increase in transcripts of ABCA12, GBA, SMPD1 and TNFα, while the induction of these genes was significantly decreased in NHEK pretreated with TLR3 siRNA (Figure 3).

Bottom Line: UV damage to the skin leads to the release of noncoding RNA (ncRNA) from necrotic keratinocytes that activates Toll-like receptor 3 (TLR3).This release of ncRNA triggers inflammation in the skin following UV damage.Combined, these data further validate the conclusion that recognition of endogenous RNA by TLR3 is an important step in the program of skin barrier repair.

View Article: PubMed Central - PubMed

Affiliation: Division of Dermatology, Department of Medicine, University of California, San Diego, La Jolla, California, USA.

ABSTRACT
UV damage to the skin leads to the release of noncoding RNA (ncRNA) from necrotic keratinocytes that activates Toll-like receptor 3 (TLR3). This release of ncRNA triggers inflammation in the skin following UV damage. Recently, TLR3 activation was also shown to aid wound repair and increase the expression of genes associated with permeability barrier repair. Here, we sought to test whether skin barrier repair after UVB damage is dependent on the activation of TLR3. We observed that multiple ncRNAs induced expression of skin barrier repair genes, that the TLR3 ligand Poly (I:C) also induced expression and function of tight junctions, and that the ncRNA U1 acts in a TLR3-dependent manner to induce expression of skin barrier repair genes. These observations were shown to have functional relevance as Tlr3-/- mice displayed a delay in skin barrier repair following UVB damage. Combined, these data further validate the conclusion that recognition of endogenous RNA by TLR3 is an important step in the program of skin barrier repair.

Show MeSH
Related in: MedlinePlus