- Email: [email protected]
Upregulation of Toll-Like Receptors (TLRs) 6, 7, and 8 in Keloid Scars
LETTERS TO THE EDITOR
Upregulation of Toll-Like Receptors (TLRs) 6, 7, and 8 in Keloid Scars Journal of Investigative Dermatology (2011) 131, 2128–2130; doi:10.1038/jid.2011.163; published online 16 June 2011
TO THE EDITOR Keloid scar (KS) is a benign fibroproliferative dermal tumor of unknown origin that develops in genetically susceptible individuals (Shih and Bayat, 2009). KS commonly occurs following
trauma to the skin, which is likely to facilitate inoculation of infectious agents. Interestingly, it has been repeatedly observed that KS develops after clinical evidence of viral infection, such as chicken pox (Gathse et al.,
2003) and zoster (Manikhas et al., 1986; Koley et al., 2009). In addition, it has been reported that some skin tumors such as Merkel cell carcinoma are associated with viruses (Masahiro et al., 2009). On this basis, it has been
Papillary dermis 40
40
30 25 20 15 10
25 20 15 10
0 TLR-2
TLR-3
TLR-6
TLR-7
TLR-8
Epidermis 50
** **
45 40
TLR-2
TLR-9
TLR-3
TLR-6
TLR-8
** *
TLR-6** TLR-7*
TLR-6** TLR-7**
35 TLR-6 TLR-7
25
TLR-9
Schematic model
d
30
TLR-7
Epidermis
0
Intensity in epidermis (AU µm–1)
30
5
5
c
* *
35 Intensity in ret. dermis (AU µm–1)
35 Intensity in pap. dermis (AU µm–1)
Reticular dermis
b
* *
20 15
TLR-8*
TLR-8*
10 5 0 TLR-2
TLR-3
TLR-6
TLR-7
TLR-8
Intralesional
TLR-9
Perilesional
Extralesional
Extralesional
Perilesional
Keloid
Dermis
a
Intralesional
Normal skin
Figure 1. Toll-like receptor (TLR) protein expression in keloid scar in situ. Quantitative immunohistochemistry of expression of TLRs 2, 3, and 6–9 in papillary dermis (a) reticular dermis (b), and epidermis (c) in comparison with normal skin, and a schematic model illustrating the increased TLR expression at keloid scar-defined sites (d). Paraffin-embedded tissues for keloid (n ¼ 9) and normal skin (n ¼ 7) were sectioned at 5 mm, dewaxed, and dehydrated. TLRs antigens were then detected using fluorescence: Alexa 488/564 (Invitrogen, Paisley, UK). Images were captured using a light microscope (Olympus, Essex, UK). Morphometric analysis was performed for epidermis, papillary, and reticular dermis in three random fields using Image J software (version1.42). Statistical significance was calculated using independent t-test. Error bars represent mean±SEM. *Pp0.05 and **Pp0.01. AU, arbitrary units; pap., papillary; ret., reticular.
Abbreviations: KS, keloid scar; QRT-PCR, quantitative real-time RT-PCR; TLR, Toll-like receptor
2128 Journal of Investigative Dermatology (2011), Volume 131
& 2011 The Society for Investigative Dermatology
RA Bagabir et al. Upregulation of TLRs 6, 7, and 8 in Keloid Scars
extralesional KS or normal skin (Supplementary Table S3 online). This protein expression pattern corresponded well with the substantial upregulation in the TLR-8 mRNA in intra- and perilesional sites of KS, as measured by QRTPCR with 4.2- and 2.1-fold change, respectively, relative to normal skin (Figure 2). Although there was no obvious increase in TLR-8 protein expression in situ in extralesional skin of KS patients (Figure 1a and b), transcription of TLR-8 was increased by 2.5-fold change compared with normal control skin (Figure 2). With respect to the immunoreactivity of TLR-2, -3, -6, -7, and -9, no significant immunoreactivity differences were observed in the dermis of KS lesion compared with control dermis (Figure 1a and b; and Supplementary Figure S2 online). The trans-
cript steady-state level of TLR-9 within the keloid lesion was significantly upregulated (intralesional P ¼ 0.02 and perilesional P ¼ 0.04) relative to normal skin (Figure 2). However, TLR-9 protein expression was not significantly changed (Figure 1a–c). TLR-6 transcription was slightly upregulated in intralesional sites, whereas TLR-7 transcription was upregulated across the different keloid lesional sites (Figure 2). There was a significant increase in TLR-6 (P ¼ 0.01) and TLR-7 (Pp0.02) immunoreactivity in situ when the epidermis only was compared between KS and normal control skin (Figure 1c, Supplementary Figure S1 online). In the epidermis, TLR-2 and TLR-3 gene expressions were upregulated within KS, whereas the in situ immunoreactivity was decreased (Figures 1 and 2). The antibody specificity of TLRs 6–8 was also confirmed
100
* 10
*
*
1 0
Intralesional Perilesional Extralesional
TLR-2 3.1 1.6 0.5
TLR-3 1.8 1.1 0.5
TLR-6 1.1 0.5 0.9
TLR-7 1.6 1.4 1.9
TLR-8 4.2 2.1 2.5
TLR-9 14.4 4.8 1.4
TLR-8* TLR-9* TLR-7 TLR-6 Keloid
Dermis
TLR-8 TLR-9 TLR-7
TLR-8 TLR-9 TLR-7
Extralesional
Perilesional
Intralesional
Full-thickness mRNA
Schematic model
b
Epidermis
a
Gene fold expression relative to normal skin
speculated that KS might be induced by viral infection (Alonso et al., 2008); nonetheless, there is no experimental evidence in support of this hypothesis. A previous attempt at identifying viral DNA directly in KS was unsuccessful, as it failed to identify human herpesvirus-8 or Epstein–Barr virus DNA in seven keloid cases (Pantanowitz and Duke, 2008). However, it is possible that the experimental technique employed in this study was neither sensitive nor searched for the appropriate viral particle. Thus, not knowing the identity of the viral agent, we have approached this question using an alternative approach. In this pilot study, we asked whether any evidence could be identified that points to a viral encounter by the skin immune system in KS. To this end, we specifically investigated the in situ expression of Toll-like receptors (TLRs) known to recognize single- or doublestranded viral particles, i.e., TLRs 2, 3, and 6-9 (Delaloye et al., 2009; O’Neill and Bowie, 2010) by fluorescence and assessed by quantitative immunohistomorphometry (Kloepper et al., 2009). These expressions were followed-up by quantitative real-time RT-PCR (QRT-PCR; see Supplementary Table S1 online for primer sequences and gene bank accession numbers). The expression of these TLRs was compared with carefully defined sites (Supplementary Figure S1 online) within and immediately outside the keloid lesion (‘‘intralesional’’: core of keloid, ‘‘perilesional’’: keloid’s margin, and ‘‘extralesional’’: normal uninvolved skin adjacent to KSs), obtained from 13 KS patients (see demographic data in Supplementary Table S2 online). This was compared with normal skin (nine patients) from the vicinity of a normal scar (patients with no history of raised scarring). As shown in Figure 1a and b, immunoreactivity for TLR-8 was significantly increased (Po0.05) in intra- and perilesional sites of KS (see Supplementary Figure S2 online for representative images) relative to normal dermis. The increased intensity of TLR-8 immunoreactivity was associated with scattered positive cells within the intraand perilesional sites of KS, whereas no TLR-positive cells were observed in
Figure 2. Toll-like receptor (TLR) transcription in keloid scar. Fold change of transcripts of TLRs 2, 3, and 6–9 in keloid scar (KS)-defined lesional sites relative to normal skin (a) and a schematic model illustrating the increased TLR expression at KS-defined sites (b). Primers for TLRs were designed by and purchased from Roche Diagnostics, West Sussex, UK (Supplementary Table S1 online). mRNA was extracted from full-thickness tissue derived from defined KS sites (n ¼ 7) and normal skin (n ¼ 7). In all, 2 mg of mRNA was reverse transcribed and quantitative real-time RT-PCR reactions were carried out. The cycle threshold (Ct) values were normalized to the geometric mean of two housekeeping genes (SDHA (succinate dehydrogenase complex subunit A) and RPL32 (60S ribosomal protein L32)) and analyzed by fold change (2DDCT) relative to normal skin. Error bars represent mean±SEM. *Po0.05 and **Pp0.01.
www.jidonline.org 2129
RA Bagabir et al. Upregulation of TLRs 6, 7, and 8 in Keloid Scars
by using the corresponding blocking peptide for each TLR (Supplementary Figure S4 online). As these findings suggest a heightened responsiveness of the skin innate immune system toward classical viral infection-associated TLR ligands (Delaloye et al., 2009; O’Neill and Bowie, 2010), this preliminary study offers indirect support for the viral hypothesis of KS pathogenesis (Alonso et al., 2008). The increased epidermal protein expression for TLR-6 and -7 in KS is noteworthy, as keloid keratinocytes may have a role in stimulating keloid fibroblast activity (Lim et al., 2002). Although a previous study has failed to demonstrate TLR-7 expression in normal human keratinocytes (Lebre et al., 2006), TLR-7 expression has recently been detected in normal and virally infected human keratinocytes (Ku et al., 2008). This is well in line with our current results. The markedly increased upregulation of the TLR-8 gene and protein levels in keloid dermis may reflect the possible encounter of intradermal immunocytes, such as dermal dendrocytes, and/or macrophages with virus-associated ligands (Heydtmann, 2009). Viruses such as influenza virus, parechovirus 1, and modified vaccinia virus Ankara have been identified as triggers of antiviral pathways through activation of TLRs 6–8 (Triantafilou et al., 2005; Delaloye et al., 2009). However, it is uncertain whether viral ligands are responsible for the observed upregulation of TLR-6, -7, and -8 in KS. It also remains to be further investigated whether non-viral ligands of TLRs 6–8 may influence keloid etiopathogenesis by stimulating TLR receptors. Given that viral infection is among the most potent stimuli for upregulating TLRs (Alonso et al., 2008; Delaloye et al., 2009), it is reasonable to systematically explore the involvement of either viral or non-viral stimuli in keloid pathogenesis. Existing KS
organ culture models may be utilized to investigate whether antagonizing TLRs 6–8-mediated signaling and/or downregulation of these receptors may impact on keloid progression and resolution. NHS local and regional ethical approval as well as institutional approval from University Hospital South Manchester was obtained for carrying out this research. All patients and controls gave full ethically approved informed consent. The study was carried out with strict adherence to the Declaration of Helsinki protocols. CONFLICT OF INTEREST The authors state no conflict of interest.
ACKNOWLEDGMENTS We thank Professor Werner Mu¨ller for his expert advice. This study was partially supported by a grant from the Ministry of Higher Education in Saudi Arabia.
Rania A. Bagabir1,2, Farhatullah Syed1,2, Riina Rautemaa3,4,5, Duncan Angus McGrouther1,6, Ralf Paus2,7 and Ardeshir Bayat1,2,6 1 Plastic and Reconstructive Surgery Research, Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, UK; 2 Dermatological Sciences, Inflammation Sciences, School of Translational Medicine, University of Manchester, Manchester, UK; 3 Department of Bacteriology and Immunology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland; 4 Department of Oral and Maxillofacial Diseases, Surgical Hospital, Helsinki University Central Hospital, Helsinki, Finland; 5School of Translational Medicine, Manchester Academic Health Science Centre, University of Manchester and South Manchester University Hospital, Manchester, UK; 6Plastic and Reconstructive Surgery Research, South Manchester University Hospital, Manchester, UK and 7Department of Dermatology, University of Luebeck, Luebeck, Germany. E-mail: [email protected]
SUPPLEMENTARY MATERIAL Supplementary material is linked to the online version of the paper at http://www.nature.com/jid
2130 Journal of Investigative Dermatology (2011), Volume 131
REFERENCES Alonso PE, Rioja LF, Pera C (2008) Keloids: a viral hypothesis. Med Hypotheses 70:156–66 Delaloye J, Roger T, Steiner-Tardivel QG et al. (2009) Innate immune sensing of modified vaccinia virus Ankara (MVA) is mediated by TLR2-TLR6, MDA-5 and the NALP3 inflammasome. PLoS Pathog 5:e1000480 Gathse A, Ibara JR, Obengui P et al. (2003) Gigantic keloı¨ds after chicken-pox. A case report. Bull Soc Pathol Exot 96:401–2 Heydtmann M (2009) Macrophages in hepatitis B and hepatitis C virus infections. J Virol 83:2796–802 Kloepper JE, Koji S, Yusur A-N et al. (2009) Methods in hair research: how to objectively distinguish between anagen and catagen in human hair follicle organ culture. Exp Dermatol 19:305–12 Koley S, Saoji V, Salodkar A (2009) Unusual formation of keloids after each episode of recurrent herpes zoster in an HIV positive patient. Indian J Sex Transm Dis 30:109–11 Ku JK, Kwon HJ, Kim M-Y et al. (2008) Expression of Toll-like receptors in verruca and molluscum contagiosum. J Korean Med Sci 23:307–14 Lebre MC, van der Aar AMG, van Baarsen L et al. (2006) Human keratinocytes express functional Toll-like receptor 3, 4, 5, and 9. J Invest Dermatol 127:331–41 Lim IJ, Phan T-T, Bay B-H et al. (2002) Fibroblasts cocultured with keloid keratinocytes: normal fibroblasts secrete collagen in a keloidlike manner. Am J Physiol Cell Physiol 283: C212–22 Manikhas MG, Egorova MA, Orlova EV (1986) Keloid scars as a sequel of herpes zoster. Vestn Dermatol Venerol 9:54–5 Masahiro S, Reety A, Hyun Jin K et al. (2009) Human Merkel cell polyomavirus infection I. MCV T antigen expression in Merkel cell carcinoma, lymphoid tissues and lymphoid tumors. Int J Cancer 125: 1243–9 O’Neill LAJ, Bowie AG (2010) Sensing and signaling in antiviral innate immunity. Curr Biol 20:R328–33 Pantanowitz L, Duke WH (2008) Keloids do not harbor EBV or HHV8. Med Hypotheses 70:704 Shih B, Bayat A (2009) Genetics of keloid scarring. Arch Dermatol Res 302:319–39 Triantafilou K, Vakakis E, Orthopoulos G et al. (2005) TLR8 and TLR7 are involved in the host’s immune response to human parechovirus 1. Eur J Immunol 35:2416–23
Copyright of Journal of Investigative Dermatology is the property of Nature Publishing Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Upregulation of Toll-Like Receptors (TLRs) 6, 7, and 8 in Keloid Scars Journal of Investigative Dermatology (2011) 131, 2128–2130; doi:10.1038/jid.2011.163; published online 16 June 2011
TO THE EDITOR Keloid scar (KS) is a benign fibroproliferative dermal tumor of unknown origin that develops in genetically susceptible individuals (Shih and Bayat, 2009). KS commonly occurs following
trauma to the skin, which is likely to facilitate inoculation of infectious agents. Interestingly, it has been repeatedly observed that KS develops after clinical evidence of viral infection, such as chicken pox (Gathse et al.,
2003) and zoster (Manikhas et al., 1986; Koley et al., 2009). In addition, it has been reported that some skin tumors such as Merkel cell carcinoma are associated with viruses (Masahiro et al., 2009). On this basis, it has been
Papillary dermis 40
40
30 25 20 15 10
25 20 15 10
0 TLR-2
TLR-3
TLR-6
TLR-7
TLR-8
Epidermis 50
** **
45 40
TLR-2
TLR-9
TLR-3
TLR-6
TLR-8
** *
TLR-6** TLR-7*
TLR-6** TLR-7**
35 TLR-6 TLR-7
25
TLR-9
Schematic model
d
30
TLR-7
Epidermis
0
Intensity in epidermis (AU µm–1)
30
5
5
c
* *
35 Intensity in ret. dermis (AU µm–1)
35 Intensity in pap. dermis (AU µm–1)
Reticular dermis
b
* *
20 15
TLR-8*
TLR-8*
10 5 0 TLR-2
TLR-3
TLR-6
TLR-7
TLR-8
Intralesional
TLR-9
Perilesional
Extralesional
Extralesional
Perilesional
Keloid
Dermis
a
Intralesional
Normal skin
Figure 1. Toll-like receptor (TLR) protein expression in keloid scar in situ. Quantitative immunohistochemistry of expression of TLRs 2, 3, and 6–9 in papillary dermis (a) reticular dermis (b), and epidermis (c) in comparison with normal skin, and a schematic model illustrating the increased TLR expression at keloid scar-defined sites (d). Paraffin-embedded tissues for keloid (n ¼ 9) and normal skin (n ¼ 7) were sectioned at 5 mm, dewaxed, and dehydrated. TLRs antigens were then detected using fluorescence: Alexa 488/564 (Invitrogen, Paisley, UK). Images were captured using a light microscope (Olympus, Essex, UK). Morphometric analysis was performed for epidermis, papillary, and reticular dermis in three random fields using Image J software (version1.42). Statistical significance was calculated using independent t-test. Error bars represent mean±SEM. *Pp0.05 and **Pp0.01. AU, arbitrary units; pap., papillary; ret., reticular.
Abbreviations: KS, keloid scar; QRT-PCR, quantitative real-time RT-PCR; TLR, Toll-like receptor
2128 Journal of Investigative Dermatology (2011), Volume 131
& 2011 The Society for Investigative Dermatology
RA Bagabir et al. Upregulation of TLRs 6, 7, and 8 in Keloid Scars
extralesional KS or normal skin (Supplementary Table S3 online). This protein expression pattern corresponded well with the substantial upregulation in the TLR-8 mRNA in intra- and perilesional sites of KS, as measured by QRTPCR with 4.2- and 2.1-fold change, respectively, relative to normal skin (Figure 2). Although there was no obvious increase in TLR-8 protein expression in situ in extralesional skin of KS patients (Figure 1a and b), transcription of TLR-8 was increased by 2.5-fold change compared with normal control skin (Figure 2). With respect to the immunoreactivity of TLR-2, -3, -6, -7, and -9, no significant immunoreactivity differences were observed in the dermis of KS lesion compared with control dermis (Figure 1a and b; and Supplementary Figure S2 online). The trans-
cript steady-state level of TLR-9 within the keloid lesion was significantly upregulated (intralesional P ¼ 0.02 and perilesional P ¼ 0.04) relative to normal skin (Figure 2). However, TLR-9 protein expression was not significantly changed (Figure 1a–c). TLR-6 transcription was slightly upregulated in intralesional sites, whereas TLR-7 transcription was upregulated across the different keloid lesional sites (Figure 2). There was a significant increase in TLR-6 (P ¼ 0.01) and TLR-7 (Pp0.02) immunoreactivity in situ when the epidermis only was compared between KS and normal control skin (Figure 1c, Supplementary Figure S1 online). In the epidermis, TLR-2 and TLR-3 gene expressions were upregulated within KS, whereas the in situ immunoreactivity was decreased (Figures 1 and 2). The antibody specificity of TLRs 6–8 was also confirmed
100
* 10
*
*
1 0
Intralesional Perilesional Extralesional
TLR-2 3.1 1.6 0.5
TLR-3 1.8 1.1 0.5
TLR-6 1.1 0.5 0.9
TLR-7 1.6 1.4 1.9
TLR-8 4.2 2.1 2.5
TLR-9 14.4 4.8 1.4
TLR-8* TLR-9* TLR-7 TLR-6 Keloid
Dermis
TLR-8 TLR-9 TLR-7
TLR-8 TLR-9 TLR-7
Extralesional
Perilesional
Intralesional
Full-thickness mRNA
Schematic model
b
Epidermis
a
Gene fold expression relative to normal skin
speculated that KS might be induced by viral infection (Alonso et al., 2008); nonetheless, there is no experimental evidence in support of this hypothesis. A previous attempt at identifying viral DNA directly in KS was unsuccessful, as it failed to identify human herpesvirus-8 or Epstein–Barr virus DNA in seven keloid cases (Pantanowitz and Duke, 2008). However, it is possible that the experimental technique employed in this study was neither sensitive nor searched for the appropriate viral particle. Thus, not knowing the identity of the viral agent, we have approached this question using an alternative approach. In this pilot study, we asked whether any evidence could be identified that points to a viral encounter by the skin immune system in KS. To this end, we specifically investigated the in situ expression of Toll-like receptors (TLRs) known to recognize single- or doublestranded viral particles, i.e., TLRs 2, 3, and 6-9 (Delaloye et al., 2009; O’Neill and Bowie, 2010) by fluorescence and assessed by quantitative immunohistomorphometry (Kloepper et al., 2009). These expressions were followed-up by quantitative real-time RT-PCR (QRT-PCR; see Supplementary Table S1 online for primer sequences and gene bank accession numbers). The expression of these TLRs was compared with carefully defined sites (Supplementary Figure S1 online) within and immediately outside the keloid lesion (‘‘intralesional’’: core of keloid, ‘‘perilesional’’: keloid’s margin, and ‘‘extralesional’’: normal uninvolved skin adjacent to KSs), obtained from 13 KS patients (see demographic data in Supplementary Table S2 online). This was compared with normal skin (nine patients) from the vicinity of a normal scar (patients with no history of raised scarring). As shown in Figure 1a and b, immunoreactivity for TLR-8 was significantly increased (Po0.05) in intra- and perilesional sites of KS (see Supplementary Figure S2 online for representative images) relative to normal dermis. The increased intensity of TLR-8 immunoreactivity was associated with scattered positive cells within the intraand perilesional sites of KS, whereas no TLR-positive cells were observed in
Figure 2. Toll-like receptor (TLR) transcription in keloid scar. Fold change of transcripts of TLRs 2, 3, and 6–9 in keloid scar (KS)-defined lesional sites relative to normal skin (a) and a schematic model illustrating the increased TLR expression at KS-defined sites (b). Primers for TLRs were designed by and purchased from Roche Diagnostics, West Sussex, UK (Supplementary Table S1 online). mRNA was extracted from full-thickness tissue derived from defined KS sites (n ¼ 7) and normal skin (n ¼ 7). In all, 2 mg of mRNA was reverse transcribed and quantitative real-time RT-PCR reactions were carried out. The cycle threshold (Ct) values were normalized to the geometric mean of two housekeeping genes (SDHA (succinate dehydrogenase complex subunit A) and RPL32 (60S ribosomal protein L32)) and analyzed by fold change (2DDCT) relative to normal skin. Error bars represent mean±SEM. *Po0.05 and **Pp0.01.
www.jidonline.org 2129
RA Bagabir et al. Upregulation of TLRs 6, 7, and 8 in Keloid Scars
by using the corresponding blocking peptide for each TLR (Supplementary Figure S4 online). As these findings suggest a heightened responsiveness of the skin innate immune system toward classical viral infection-associated TLR ligands (Delaloye et al., 2009; O’Neill and Bowie, 2010), this preliminary study offers indirect support for the viral hypothesis of KS pathogenesis (Alonso et al., 2008). The increased epidermal protein expression for TLR-6 and -7 in KS is noteworthy, as keloid keratinocytes may have a role in stimulating keloid fibroblast activity (Lim et al., 2002). Although a previous study has failed to demonstrate TLR-7 expression in normal human keratinocytes (Lebre et al., 2006), TLR-7 expression has recently been detected in normal and virally infected human keratinocytes (Ku et al., 2008). This is well in line with our current results. The markedly increased upregulation of the TLR-8 gene and protein levels in keloid dermis may reflect the possible encounter of intradermal immunocytes, such as dermal dendrocytes, and/or macrophages with virus-associated ligands (Heydtmann, 2009). Viruses such as influenza virus, parechovirus 1, and modified vaccinia virus Ankara have been identified as triggers of antiviral pathways through activation of TLRs 6–8 (Triantafilou et al., 2005; Delaloye et al., 2009). However, it is uncertain whether viral ligands are responsible for the observed upregulation of TLR-6, -7, and -8 in KS. It also remains to be further investigated whether non-viral ligands of TLRs 6–8 may influence keloid etiopathogenesis by stimulating TLR receptors. Given that viral infection is among the most potent stimuli for upregulating TLRs (Alonso et al., 2008; Delaloye et al., 2009), it is reasonable to systematically explore the involvement of either viral or non-viral stimuli in keloid pathogenesis. Existing KS
organ culture models may be utilized to investigate whether antagonizing TLRs 6–8-mediated signaling and/or downregulation of these receptors may impact on keloid progression and resolution. NHS local and regional ethical approval as well as institutional approval from University Hospital South Manchester was obtained for carrying out this research. All patients and controls gave full ethically approved informed consent. The study was carried out with strict adherence to the Declaration of Helsinki protocols. CONFLICT OF INTEREST The authors state no conflict of interest.
ACKNOWLEDGMENTS We thank Professor Werner Mu¨ller for his expert advice. This study was partially supported by a grant from the Ministry of Higher Education in Saudi Arabia.
Rania A. Bagabir1,2, Farhatullah Syed1,2, Riina Rautemaa3,4,5, Duncan Angus McGrouther1,6, Ralf Paus2,7 and Ardeshir Bayat1,2,6 1 Plastic and Reconstructive Surgery Research, Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, UK; 2 Dermatological Sciences, Inflammation Sciences, School of Translational Medicine, University of Manchester, Manchester, UK; 3 Department of Bacteriology and Immunology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland; 4 Department of Oral and Maxillofacial Diseases, Surgical Hospital, Helsinki University Central Hospital, Helsinki, Finland; 5School of Translational Medicine, Manchester Academic Health Science Centre, University of Manchester and South Manchester University Hospital, Manchester, UK; 6Plastic and Reconstructive Surgery Research, South Manchester University Hospital, Manchester, UK and 7Department of Dermatology, University of Luebeck, Luebeck, Germany. E-mail: [email protected]
SUPPLEMENTARY MATERIAL Supplementary material is linked to the online version of the paper at http://www.nature.com/jid
2130 Journal of Investigative Dermatology (2011), Volume 131
REFERENCES Alonso PE, Rioja LF, Pera C (2008) Keloids: a viral hypothesis. Med Hypotheses 70:156–66 Delaloye J, Roger T, Steiner-Tardivel QG et al. (2009) Innate immune sensing of modified vaccinia virus Ankara (MVA) is mediated by TLR2-TLR6, MDA-5 and the NALP3 inflammasome. PLoS Pathog 5:e1000480 Gathse A, Ibara JR, Obengui P et al. (2003) Gigantic keloı¨ds after chicken-pox. A case report. Bull Soc Pathol Exot 96:401–2 Heydtmann M (2009) Macrophages in hepatitis B and hepatitis C virus infections. J Virol 83:2796–802 Kloepper JE, Koji S, Yusur A-N et al. (2009) Methods in hair research: how to objectively distinguish between anagen and catagen in human hair follicle organ culture. Exp Dermatol 19:305–12 Koley S, Saoji V, Salodkar A (2009) Unusual formation of keloids after each episode of recurrent herpes zoster in an HIV positive patient. Indian J Sex Transm Dis 30:109–11 Ku JK, Kwon HJ, Kim M-Y et al. (2008) Expression of Toll-like receptors in verruca and molluscum contagiosum. J Korean Med Sci 23:307–14 Lebre MC, van der Aar AMG, van Baarsen L et al. (2006) Human keratinocytes express functional Toll-like receptor 3, 4, 5, and 9. J Invest Dermatol 127:331–41 Lim IJ, Phan T-T, Bay B-H et al. (2002) Fibroblasts cocultured with keloid keratinocytes: normal fibroblasts secrete collagen in a keloidlike manner. Am J Physiol Cell Physiol 283: C212–22 Manikhas MG, Egorova MA, Orlova EV (1986) Keloid scars as a sequel of herpes zoster. Vestn Dermatol Venerol 9:54–5 Masahiro S, Reety A, Hyun Jin K et al. (2009) Human Merkel cell polyomavirus infection I. MCV T antigen expression in Merkel cell carcinoma, lymphoid tissues and lymphoid tumors. Int J Cancer 125: 1243–9 O’Neill LAJ, Bowie AG (2010) Sensing and signaling in antiviral innate immunity. Curr Biol 20:R328–33 Pantanowitz L, Duke WH (2008) Keloids do not harbor EBV or HHV8. Med Hypotheses 70:704 Shih B, Bayat A (2009) Genetics of keloid scarring. Arch Dermatol Res 302:319–39 Triantafilou K, Vakakis E, Orthopoulos G et al. (2005) TLR8 and TLR7 are involved in the host’s immune response to human parechovirus 1. Eur J Immunol 35:2416–23
Copyright of Journal of Investigative Dermatology is the property of Nature Publishing Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.