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Innate defense regulator peptide 1018 in wound healing and wound infection.

Steinstraesser L, Hirsch T, Schulte M, Kueckelhaus M, Jacobsen F, Mersch EA, Stricker I, Afacan N, Jenssen H, Hancock RE, Kindrachuk J - PLoS ONE (2012)

Bottom Line: IDR-1018 was significantly less cytotoxic in vitro as compared to either LL-37 or HB-107.Furthermore, administration of IDR-1018 resulted in a dose-dependent increase in fibroblast cellular respiration.However, no significant differences in bacterial colonization were observed.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany. lars.steinstraesser@ruhr-uni-bochum.de

ABSTRACT
Innate defense regulators (IDRs) are synthetic immunomodulatory versions of natural host defense peptides (HDP). IDRs mediate protection against bacterial challenge in the absence of direct antimicrobial activity, representing a novel approach to anti-infective and anti-inflammatory therapy. Previously, we reported that IDR-1018 selectively induced chemokine responses and suppressed pro-inflammatory responses. As there has been an increasing appreciation for the ability of HDPs to modulate complex immune processes, including wound healing, we characterized the wound healing activities of IDR-1018 in vitro. Further, we investigated the efficacy of IDR-1018 in diabetic and non-diabetic wound healing models. In all experiments, IDR-1018 was compared to the human HDP LL-37 and HDP-derived wound healing peptide HB-107. IDR-1018 was significantly less cytotoxic in vitro as compared to either LL-37 or HB-107. Furthermore, administration of IDR-1018 resulted in a dose-dependent increase in fibroblast cellular respiration. In vivo, IDR-1018 demonstrated significantly accelerated wound healing in S. aureus infected porcine and non-diabetic but not in diabetic murine wounds. However, no significant differences in bacterial colonization were observed. Our investigation demonstrates that in addition to previously reported immunomodulatory activities IDR-1018 promotes wound healing independent of direct antibacterial activity. Interestingly, these effects were not observed in diabetic wounds. It is anticipated that the wound healing activities of IDR-1018 can be attributed to modulation of host immune pathways that are suppressed in diabetic wounds and provide further evidence of the multiple immunomodulatory activities of IDR-1018.

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Lack of IDR-1018 toxicity.The effects of IDR-1018, LL-37 and HB-107 on viability/metabolic activity were determined using an MTT-Assay with HaCaT cells (left) and primary human fibroblasts (HFB; right) at the indicated concentrations. Cells were incubated with peptides for 24 hours. Standard deviation was calculated out of three independent experiments and assessed as SEM (Statistical significance IDR-1018 vs. LL-37: *  = p<0.05; **  = p<0.01; ***  = p<0.005; IDR-1018 vs. HB-107+ = p<0.05).
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pone-0039373-g001: Lack of IDR-1018 toxicity.The effects of IDR-1018, LL-37 and HB-107 on viability/metabolic activity were determined using an MTT-Assay with HaCaT cells (left) and primary human fibroblasts (HFB; right) at the indicated concentrations. Cells were incubated with peptides for 24 hours. Standard deviation was calculated out of three independent experiments and assessed as SEM (Statistical significance IDR-1018 vs. LL-37: *  = p<0.05; **  = p<0.01; ***  = p<0.005; IDR-1018 vs. HB-107+ = p<0.05).

Mentions: To investigate of effects of IDR-1018 on cell oxidative metabolism, an MTT-Assay was performed on HaCaT (immortalized human keratinocyte cell line) and primary human fibroblasts (HFB). In this assay, toxicity is assessed as residual metabolic activity through the production of MTT formazan crystals by mitochondrial dehydrogenases in living cells. The HDPs LL-37 and HB-107 served as peptide controls for naturally occurring and synthetic HDPs with wound healing activity [21], [30]. IDR-1018 treated HaCaT cells maintained cell viability better than those treated with LL-37 or HB-107 at all concentrations analyzed in this study (Fig. 1). In all samples, cell viability was affected in a concentration dependent manner. LL-37 showed a significant decrease in cell viability at higher concentrations (10% compared to untreated cells at 200 µg/ml (p<0.0001), consistent with literature data demonstrating that this peptide is cytotoxic at higher concentrations. Moreover, HB-107 exhibited a reduction in HaCaT cell viability of up to 50% compared to untreated cells (p<0.0001). In contrast, IDR-1018 administration had very little effect on the metabolic activity of HaCaT cells as compared to LL-37 and HB-107 (78% residual metabolic activity at 200 µg/ml; p<0.0001 compared to LL-37 and or p<0.001 compared to HB-107 or p = 0.0013 compared to untreated cells).


Innate defense regulator peptide 1018 in wound healing and wound infection.

Steinstraesser L, Hirsch T, Schulte M, Kueckelhaus M, Jacobsen F, Mersch EA, Stricker I, Afacan N, Jenssen H, Hancock RE, Kindrachuk J - PLoS ONE (2012)

Lack of IDR-1018 toxicity.The effects of IDR-1018, LL-37 and HB-107 on viability/metabolic activity were determined using an MTT-Assay with HaCaT cells (left) and primary human fibroblasts (HFB; right) at the indicated concentrations. Cells were incubated with peptides for 24 hours. Standard deviation was calculated out of three independent experiments and assessed as SEM (Statistical significance IDR-1018 vs. LL-37: *  = p<0.05; **  = p<0.01; ***  = p<0.005; IDR-1018 vs. HB-107+ = p<0.05).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3412849&req=5

pone-0039373-g001: Lack of IDR-1018 toxicity.The effects of IDR-1018, LL-37 and HB-107 on viability/metabolic activity were determined using an MTT-Assay with HaCaT cells (left) and primary human fibroblasts (HFB; right) at the indicated concentrations. Cells were incubated with peptides for 24 hours. Standard deviation was calculated out of three independent experiments and assessed as SEM (Statistical significance IDR-1018 vs. LL-37: *  = p<0.05; **  = p<0.01; ***  = p<0.005; IDR-1018 vs. HB-107+ = p<0.05).
Mentions: To investigate of effects of IDR-1018 on cell oxidative metabolism, an MTT-Assay was performed on HaCaT (immortalized human keratinocyte cell line) and primary human fibroblasts (HFB). In this assay, toxicity is assessed as residual metabolic activity through the production of MTT formazan crystals by mitochondrial dehydrogenases in living cells. The HDPs LL-37 and HB-107 served as peptide controls for naturally occurring and synthetic HDPs with wound healing activity [21], [30]. IDR-1018 treated HaCaT cells maintained cell viability better than those treated with LL-37 or HB-107 at all concentrations analyzed in this study (Fig. 1). In all samples, cell viability was affected in a concentration dependent manner. LL-37 showed a significant decrease in cell viability at higher concentrations (10% compared to untreated cells at 200 µg/ml (p<0.0001), consistent with literature data demonstrating that this peptide is cytotoxic at higher concentrations. Moreover, HB-107 exhibited a reduction in HaCaT cell viability of up to 50% compared to untreated cells (p<0.0001). In contrast, IDR-1018 administration had very little effect on the metabolic activity of HaCaT cells as compared to LL-37 and HB-107 (78% residual metabolic activity at 200 µg/ml; p<0.0001 compared to LL-37 and or p<0.001 compared to HB-107 or p = 0.0013 compared to untreated cells).

Bottom Line: IDR-1018 was significantly less cytotoxic in vitro as compared to either LL-37 or HB-107.Furthermore, administration of IDR-1018 resulted in a dose-dependent increase in fibroblast cellular respiration.However, no significant differences in bacterial colonization were observed.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany. lars.steinstraesser@ruhr-uni-bochum.de

ABSTRACT
Innate defense regulators (IDRs) are synthetic immunomodulatory versions of natural host defense peptides (HDP). IDRs mediate protection against bacterial challenge in the absence of direct antimicrobial activity, representing a novel approach to anti-infective and anti-inflammatory therapy. Previously, we reported that IDR-1018 selectively induced chemokine responses and suppressed pro-inflammatory responses. As there has been an increasing appreciation for the ability of HDPs to modulate complex immune processes, including wound healing, we characterized the wound healing activities of IDR-1018 in vitro. Further, we investigated the efficacy of IDR-1018 in diabetic and non-diabetic wound healing models. In all experiments, IDR-1018 was compared to the human HDP LL-37 and HDP-derived wound healing peptide HB-107. IDR-1018 was significantly less cytotoxic in vitro as compared to either LL-37 or HB-107. Furthermore, administration of IDR-1018 resulted in a dose-dependent increase in fibroblast cellular respiration. In vivo, IDR-1018 demonstrated significantly accelerated wound healing in S. aureus infected porcine and non-diabetic but not in diabetic murine wounds. However, no significant differences in bacterial colonization were observed. Our investigation demonstrates that in addition to previously reported immunomodulatory activities IDR-1018 promotes wound healing independent of direct antibacterial activity. Interestingly, these effects were not observed in diabetic wounds. It is anticipated that the wound healing activities of IDR-1018 can be attributed to modulation of host immune pathways that are suppressed in diabetic wounds and provide further evidence of the multiple immunomodulatory activities of IDR-1018.

Show MeSH
Related in: MedlinePlus