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Toll-like receptor-4 deficiency enhances repair of UVR-induced cutaneous DNA damage by nucleotide excision repair mechanism.

Ahmad I, Simanyi E, Guroji P, Tamimi IA, delaRosa HJ, Nagar A, Nagar P, Katiyar SK, Elmets CA, Yusuf N - J. Invest. Dermatol. (2013)

Bottom Line: When cytokine levels were compared in these strains after UVB exposure, BMDCs from UV-irradiated TLR4(-/-) mice produced significantly more interleukin (IL)-12 and IL-23 cytokines (P<0.05) than BMDCs from TLR4(+/+) mice.Addition of anti-IL-12 and anti-IL-23 antibodies to BMDCs of TLR4(-/-) mice (before UVB exposure) inhibited repair of CPDs, with a concomitant decrease in XPA expression.Addition of TLR4 agonist to TLR4(+/+) BMDC cultures decreased XPA expression and inhibited CPD repair.

View Article: PubMed Central - PubMed

Affiliation: Department of Dermatology, Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA.

ABSTRACT
UVB-induced DNA damage has a critical role in the development of photoimmunosuppression. The purpose of this study was to determine whether repair of UVB-induced DNA damage is regulated by Toll-like receptor-4 (TLR4). When TLR4 gene knockout (TLR4(-/-)) and TLR4-competent (TLR4(+/+)) mice were subjected to 90 mJ cm(-2) UVB radiation locally, DNA damage in the form of cyclobutane pyrimidine dimers (CPDs) was repaired more efficiently in the skin and bone marrow-derived dendritic cells (BMDCs) of TLR4(-/-) mice in comparison to TLR4(+/+) mice. Expression of DNA repair gene XPA (xeroderma pigmentosum complementation group A) was significantly lower in skin and BMDCs of TLR4(+/+) mice than TLR4(-/-) mice after UVB exposure. When cytokine levels were compared in these strains after UVB exposure, BMDCs from UV-irradiated TLR4(-/-) mice produced significantly more interleukin (IL)-12 and IL-23 cytokines (P<0.05) than BMDCs from TLR4(+/+) mice. Addition of anti-IL-12 and anti-IL-23 antibodies to BMDCs of TLR4(-/-) mice (before UVB exposure) inhibited repair of CPDs, with a concomitant decrease in XPA expression. Addition of TLR4 agonist to TLR4(+/+) BMDC cultures decreased XPA expression and inhibited CPD repair. Thus, strategies to inhibit TLR4 may allow for immunopreventive and immunotherapeutic approaches for managing UVB-induced cutaneous DNA damage and skin cancer.

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TLR4 deficiency augments IL-12 and IL-23 mRNA expression in mouse BMDCBMDC were prepared as described in the Methods section. BMDC were exposed to acute UVB (3 mJ/cm2) radiation and thereafter harvested at 0-48 h. BMDC were obtained and analyzed for IL-12p35 and IL-23p19 expression as mentioned in the Methods section. There was an increase in (a) IL-12p35 and (b) IL-23p19 mRNA expression with increase in time post UV exposure as determined by quantitative real time PCR (qPCR), and this increase was more prominent in the BMDC of TLR4-/- mice than in the UV-exposed BMDC of TLR4+/+ mice. Similar results were obtained for (c) IL-12p35 and (d) IL-23p19 protein expression by ELISA. Experiments were conducted and repeated separately in triplicates in each group with identical results. Scale bar = 50 μm. The experiments were repeated twice with similar results. (**p<0.01 and ***p<0.001)
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Figure 3: TLR4 deficiency augments IL-12 and IL-23 mRNA expression in mouse BMDCBMDC were prepared as described in the Methods section. BMDC were exposed to acute UVB (3 mJ/cm2) radiation and thereafter harvested at 0-48 h. BMDC were obtained and analyzed for IL-12p35 and IL-23p19 expression as mentioned in the Methods section. There was an increase in (a) IL-12p35 and (b) IL-23p19 mRNA expression with increase in time post UV exposure as determined by quantitative real time PCR (qPCR), and this increase was more prominent in the BMDC of TLR4-/- mice than in the UV-exposed BMDC of TLR4+/+ mice. Similar results were obtained for (c) IL-12p35 and (d) IL-23p19 protein expression by ELISA. Experiments were conducted and repeated separately in triplicates in each group with identical results. Scale bar = 50 μm. The experiments were repeated twice with similar results. (**p<0.01 and ***p<0.001)

Mentions: Since both IL-12 and IL-23 have been reported to play an important role in DNA repair through stimulation of NER, BMDC from TLR4-/- and WT mice were exposed to UVB (3 mJ/cm2) and mRNA expression for IL-12p35 and IL-23p19 was determined. BMDC from TLR4-/- mice had higher expression of IL-12p35 and IL-23p19 at 30 minutes (**p<0.01), 24 hours (**p<0.01), and 48 hours (***p<0.001) than TLR4+/+ mice after UVB exposure (Figs. 3a, b). Similar results were obtained for IL-12p35 and IL-23p19 proteins as detected by ELISA (Figs. 3c, d).


Toll-like receptor-4 deficiency enhances repair of UVR-induced cutaneous DNA damage by nucleotide excision repair mechanism.

Ahmad I, Simanyi E, Guroji P, Tamimi IA, delaRosa HJ, Nagar A, Nagar P, Katiyar SK, Elmets CA, Yusuf N - J. Invest. Dermatol. (2013)

TLR4 deficiency augments IL-12 and IL-23 mRNA expression in mouse BMDCBMDC were prepared as described in the Methods section. BMDC were exposed to acute UVB (3 mJ/cm2) radiation and thereafter harvested at 0-48 h. BMDC were obtained and analyzed for IL-12p35 and IL-23p19 expression as mentioned in the Methods section. There was an increase in (a) IL-12p35 and (b) IL-23p19 mRNA expression with increase in time post UV exposure as determined by quantitative real time PCR (qPCR), and this increase was more prominent in the BMDC of TLR4-/- mice than in the UV-exposed BMDC of TLR4+/+ mice. Similar results were obtained for (c) IL-12p35 and (d) IL-23p19 protein expression by ELISA. Experiments were conducted and repeated separately in triplicates in each group with identical results. Scale bar = 50 μm. The experiments were repeated twice with similar results. (**p<0.01 and ***p<0.001)
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Related In: Results  -  Collection

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Figure 3: TLR4 deficiency augments IL-12 and IL-23 mRNA expression in mouse BMDCBMDC were prepared as described in the Methods section. BMDC were exposed to acute UVB (3 mJ/cm2) radiation and thereafter harvested at 0-48 h. BMDC were obtained and analyzed for IL-12p35 and IL-23p19 expression as mentioned in the Methods section. There was an increase in (a) IL-12p35 and (b) IL-23p19 mRNA expression with increase in time post UV exposure as determined by quantitative real time PCR (qPCR), and this increase was more prominent in the BMDC of TLR4-/- mice than in the UV-exposed BMDC of TLR4+/+ mice. Similar results were obtained for (c) IL-12p35 and (d) IL-23p19 protein expression by ELISA. Experiments were conducted and repeated separately in triplicates in each group with identical results. Scale bar = 50 μm. The experiments were repeated twice with similar results. (**p<0.01 and ***p<0.001)
Mentions: Since both IL-12 and IL-23 have been reported to play an important role in DNA repair through stimulation of NER, BMDC from TLR4-/- and WT mice were exposed to UVB (3 mJ/cm2) and mRNA expression for IL-12p35 and IL-23p19 was determined. BMDC from TLR4-/- mice had higher expression of IL-12p35 and IL-23p19 at 30 minutes (**p<0.01), 24 hours (**p<0.01), and 48 hours (***p<0.001) than TLR4+/+ mice after UVB exposure (Figs. 3a, b). Similar results were obtained for IL-12p35 and IL-23p19 proteins as detected by ELISA (Figs. 3c, d).

Bottom Line: When cytokine levels were compared in these strains after UVB exposure, BMDCs from UV-irradiated TLR4(-/-) mice produced significantly more interleukin (IL)-12 and IL-23 cytokines (P<0.05) than BMDCs from TLR4(+/+) mice.Addition of anti-IL-12 and anti-IL-23 antibodies to BMDCs of TLR4(-/-) mice (before UVB exposure) inhibited repair of CPDs, with a concomitant decrease in XPA expression.Addition of TLR4 agonist to TLR4(+/+) BMDC cultures decreased XPA expression and inhibited CPD repair.

View Article: PubMed Central - PubMed

Affiliation: Department of Dermatology, Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA.

ABSTRACT
UVB-induced DNA damage has a critical role in the development of photoimmunosuppression. The purpose of this study was to determine whether repair of UVB-induced DNA damage is regulated by Toll-like receptor-4 (TLR4). When TLR4 gene knockout (TLR4(-/-)) and TLR4-competent (TLR4(+/+)) mice were subjected to 90 mJ cm(-2) UVB radiation locally, DNA damage in the form of cyclobutane pyrimidine dimers (CPDs) was repaired more efficiently in the skin and bone marrow-derived dendritic cells (BMDCs) of TLR4(-/-) mice in comparison to TLR4(+/+) mice. Expression of DNA repair gene XPA (xeroderma pigmentosum complementation group A) was significantly lower in skin and BMDCs of TLR4(+/+) mice than TLR4(-/-) mice after UVB exposure. When cytokine levels were compared in these strains after UVB exposure, BMDCs from UV-irradiated TLR4(-/-) mice produced significantly more interleukin (IL)-12 and IL-23 cytokines (P<0.05) than BMDCs from TLR4(+/+) mice. Addition of anti-IL-12 and anti-IL-23 antibodies to BMDCs of TLR4(-/-) mice (before UVB exposure) inhibited repair of CPDs, with a concomitant decrease in XPA expression. Addition of TLR4 agonist to TLR4(+/+) BMDC cultures decreased XPA expression and inhibited CPD repair. Thus, strategies to inhibit TLR4 may allow for immunopreventive and immunotherapeutic approaches for managing UVB-induced cutaneous DNA damage and skin cancer.

Show MeSH
Related in: MedlinePlus