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The role of the skin barrier in modulating the effects of common skin microbial species on the inflammation, differentiation and proliferation status of epidermal keratinocytes.

Duckney P, Wong HK, Serrano J, Yaradou D, Oddos T, Stamatas GN - BMC Res Notes (2013)

Bottom Line: S. aureus induced complete keratinocyte cell death.On the contrary, topically applied S. epidermidis and P. acnes caused no inflammatory response even when tested at high concentrations, while topical S. aureus induced a weak reaction.None of the tested species were able to alter the expression of keratinocyte differentiation or expression markers, when applied topically.

View Article: PubMed Central - HTML - PubMed

Affiliation: Johnson & Johnson Santé Beauté France, 1 rue Camille Desmoulins, Issy-les-Moulineaux 92787, France. GStamata@its.jnj.com.

ABSTRACT

Background: Skin resident microbial species are often thought of either as pathogenic or commensal. However, little is known about the role of the skin barrier in modulating their potential for causing disease. To investigate this question we measured the effects of three microbial species commonly found on the skin (Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium acnes) on a reconstructed human epidermal model by either applying the bacteria on the model surface (intact barrier) or adding them to the culture medium (simulating barrier breach).

Results: When added to the medium, all of the tested species induced inflammatory responses and keratinocyte cell death with species-specific potency. P. acnes and S. epidermidis induced specific alterations in the expression of keratinocyte differentiation and proliferation markers, suggesting a barrier reparation response. S. aureus induced complete keratinocyte cell death. On the contrary, topically applied S. epidermidis and P. acnes caused no inflammatory response even when tested at high concentrations, while topical S. aureus induced a weak reaction. None of the tested species were able to alter the expression of keratinocyte differentiation or expression markers, when applied topically.

Conclusions: We show that the skin barrier prevents the effects of common skin bacteria on epidermal keratinocyte inflammation, differentiation and proliferation and highlight the importance of skin barrier in defending against the pathogenic effects of common skin bacteria.

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Related in: MedlinePlus

P. acnes and S. epidermidis added to the medium of reconstructed human epidermal equivalents induce dose-dependent proinflammatory and cytotoxic reactions. After 24 hrs incubation with bacteria at 1 × 107, 1 × 108 and 1 × 109 CFU, the interleukin (IL)-1α (A), IL-8 (B) and TNFα (C) levels in the RHE growth medium were measured. The cell viability (D) was assessed by measuring leakage of cytoplasmic Lactate Dehydrogenase (LDH) into the RHE growth medium. Data are expressed as percentage of untreated control (UnC = 100%) and are presented as mean ± one standard deviation. Single and double asterisks indicate statistically significant differences (P < 0.05 and P < 0.01) versus the untreated control.
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Figure 1: P. acnes and S. epidermidis added to the medium of reconstructed human epidermal equivalents induce dose-dependent proinflammatory and cytotoxic reactions. After 24 hrs incubation with bacteria at 1 × 107, 1 × 108 and 1 × 109 CFU, the interleukin (IL)-1α (A), IL-8 (B) and TNFα (C) levels in the RHE growth medium were measured. The cell viability (D) was assessed by measuring leakage of cytoplasmic Lactate Dehydrogenase (LDH) into the RHE growth medium. Data are expressed as percentage of untreated control (UnC = 100%) and are presented as mean ± one standard deviation. Single and double asterisks indicate statistically significant differences (P < 0.05 and P < 0.01) versus the untreated control.

Mentions: We tested the effects of bacteria added to the RHE medium, essentially underneath the RHE keratinocytes in order to mimic a scenario in which the bacteria had penetrated the epidermal barrier. Following treatment, the RHE culture medium was screened for pro-inflammatory cytokines and LDH as previously described. All of the tested species induced significant increases in the release of pro-inflammatory cytokines from the RHE keratinocytes and LDH (Figures 1, 2), indicating a pro-inflammatory and cytotoxic effect of the bacteria upon breaching of the epidermal barrier. We observed differential inflammatory and cytotoxic potency between species: P. acnes for example was least potent, inducing statistically significant increases in pro-inflammatory cytokine and LDH release only at the highest concentration tested. S. epidermidis had a greater pro-inflammatory and cytotoxic effect upon the RHE keratinocytes than P. acnes, inducing greater relative increases in cytokine and LDH release at each tested concentration, and induced statistically significant increases in cytokine and LDH release at lower concentrations than P. acnes (Figure 1). S. aureus was the most cytotoxic and pro-inflammatory of the species added to the RHE medium and stimulated a large and statistically significant increase in IL-1α and LDH release when added at just 1 × 107 CFU (Figure 2). Higher concentrations of S. aureus did not elicit greater increases in LDH, suggesting that maximal RHE keratinocyte cell death had been induced. S. aureus was even able to stimulate statistically significant increases in IL-1α and LDH release when added to the RHE medium at 1 × 102 CFU (data not shown), showing that it is highly cytotoxic. All RHEs treated with S. aureus detached from their basement filters, indicating total keratinocyte cell death. It is likely that the cytotoxicity of S. aureus in the medium induced cell death, causing the release of stored IL-1α before synthesis of IL-8 and TNFα could occur and the levels of IL-8 and TNFα released remained unaltered by S. aureus in the medium.


The role of the skin barrier in modulating the effects of common skin microbial species on the inflammation, differentiation and proliferation status of epidermal keratinocytes.

Duckney P, Wong HK, Serrano J, Yaradou D, Oddos T, Stamatas GN - BMC Res Notes (2013)

P. acnes and S. epidermidis added to the medium of reconstructed human epidermal equivalents induce dose-dependent proinflammatory and cytotoxic reactions. After 24 hrs incubation with bacteria at 1 × 107, 1 × 108 and 1 × 109 CFU, the interleukin (IL)-1α (A), IL-8 (B) and TNFα (C) levels in the RHE growth medium were measured. The cell viability (D) was assessed by measuring leakage of cytoplasmic Lactate Dehydrogenase (LDH) into the RHE growth medium. Data are expressed as percentage of untreated control (UnC = 100%) and are presented as mean ± one standard deviation. Single and double asterisks indicate statistically significant differences (P < 0.05 and P < 0.01) versus the untreated control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4225502&req=5

Figure 1: P. acnes and S. epidermidis added to the medium of reconstructed human epidermal equivalents induce dose-dependent proinflammatory and cytotoxic reactions. After 24 hrs incubation with bacteria at 1 × 107, 1 × 108 and 1 × 109 CFU, the interleukin (IL)-1α (A), IL-8 (B) and TNFα (C) levels in the RHE growth medium were measured. The cell viability (D) was assessed by measuring leakage of cytoplasmic Lactate Dehydrogenase (LDH) into the RHE growth medium. Data are expressed as percentage of untreated control (UnC = 100%) and are presented as mean ± one standard deviation. Single and double asterisks indicate statistically significant differences (P < 0.05 and P < 0.01) versus the untreated control.
Mentions: We tested the effects of bacteria added to the RHE medium, essentially underneath the RHE keratinocytes in order to mimic a scenario in which the bacteria had penetrated the epidermal barrier. Following treatment, the RHE culture medium was screened for pro-inflammatory cytokines and LDH as previously described. All of the tested species induced significant increases in the release of pro-inflammatory cytokines from the RHE keratinocytes and LDH (Figures 1, 2), indicating a pro-inflammatory and cytotoxic effect of the bacteria upon breaching of the epidermal barrier. We observed differential inflammatory and cytotoxic potency between species: P. acnes for example was least potent, inducing statistically significant increases in pro-inflammatory cytokine and LDH release only at the highest concentration tested. S. epidermidis had a greater pro-inflammatory and cytotoxic effect upon the RHE keratinocytes than P. acnes, inducing greater relative increases in cytokine and LDH release at each tested concentration, and induced statistically significant increases in cytokine and LDH release at lower concentrations than P. acnes (Figure 1). S. aureus was the most cytotoxic and pro-inflammatory of the species added to the RHE medium and stimulated a large and statistically significant increase in IL-1α and LDH release when added at just 1 × 107 CFU (Figure 2). Higher concentrations of S. aureus did not elicit greater increases in LDH, suggesting that maximal RHE keratinocyte cell death had been induced. S. aureus was even able to stimulate statistically significant increases in IL-1α and LDH release when added to the RHE medium at 1 × 102 CFU (data not shown), showing that it is highly cytotoxic. All RHEs treated with S. aureus detached from their basement filters, indicating total keratinocyte cell death. It is likely that the cytotoxicity of S. aureus in the medium induced cell death, causing the release of stored IL-1α before synthesis of IL-8 and TNFα could occur and the levels of IL-8 and TNFα released remained unaltered by S. aureus in the medium.

Bottom Line: S. aureus induced complete keratinocyte cell death.On the contrary, topically applied S. epidermidis and P. acnes caused no inflammatory response even when tested at high concentrations, while topical S. aureus induced a weak reaction.None of the tested species were able to alter the expression of keratinocyte differentiation or expression markers, when applied topically.

View Article: PubMed Central - HTML - PubMed

Affiliation: Johnson & Johnson Santé Beauté France, 1 rue Camille Desmoulins, Issy-les-Moulineaux 92787, France. GStamata@its.jnj.com.

ABSTRACT

Background: Skin resident microbial species are often thought of either as pathogenic or commensal. However, little is known about the role of the skin barrier in modulating their potential for causing disease. To investigate this question we measured the effects of three microbial species commonly found on the skin (Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium acnes) on a reconstructed human epidermal model by either applying the bacteria on the model surface (intact barrier) or adding them to the culture medium (simulating barrier breach).

Results: When added to the medium, all of the tested species induced inflammatory responses and keratinocyte cell death with species-specific potency. P. acnes and S. epidermidis induced specific alterations in the expression of keratinocyte differentiation and proliferation markers, suggesting a barrier reparation response. S. aureus induced complete keratinocyte cell death. On the contrary, topically applied S. epidermidis and P. acnes caused no inflammatory response even when tested at high concentrations, while topical S. aureus induced a weak reaction. None of the tested species were able to alter the expression of keratinocyte differentiation or expression markers, when applied topically.

Conclusions: We show that the skin barrier prevents the effects of common skin bacteria on epidermal keratinocyte inflammation, differentiation and proliferation and highlight the importance of skin barrier in defending against the pathogenic effects of common skin bacteria.

Show MeSH
Related in: MedlinePlus