An In Vivo Mouse Model of Human Skin Substitute Containing Spontaneously Sorted Melanocytes Demonstrates Physiological Changes after UVB Irradiation

Llames

The American Journal of Pathology

et al. 2010

In vivo studies of UVB effects on human skin are precluded by ethical and technical arguments on volunteers and inconceivable in cancer-prone patients such as those affected with Xeroderma Pigmentosum (XP). Establishing reliable models to address mechanistic and therapeutic matters thus remains a challenge. Here we have used the skin-humanized mouse system that circumvents most current model constraints. We assessed the UVB radiation effects including the sequential changes after acute exposure with respect to timing, dosage, and the relationship between dose and degree-sort of epidermal alteration. On Caucasian-derived regenerated skins , UVB irradiation (800 J/m 2 ) induced DNA damage (cyclobutane pyrimidine dimers) and p53 expression in exposed keratinocytes. Epidermal disorganization was observed at higher doses. In contrast, in African descent-derived regenerated skins, physiological hyperpigmentation prevented tissue alterations and DNA photolesions. The acute UVB effects seen in Caucasian-derived engrafted skins were also blocked by a physical sunscreen, demonstrating the suitability of the system for photoprotection studies. We also report the establishment of a photosensitive model through the transplantation of XP-C patient cells as part of a bioengineered skin. The inability of XP-C engrafted skin to remove DNA damaged cells was confirmed in vivo. Both the normal and XP-C versions of the skin-humanized mice proved proficient models to assess UVB-mediated DNA repair responses and provide a strong platform to test novel therapeutic strategies.

Section: Discussionmentioning

confidence: 99%

In Vivo Assessment of Acute UVB Responses in Normal and Xeroderma Pigmentosum (XP-C) Skin-Humanized Mouse Models

Llames

The American Journal of Pathology

et al. 2010

“…The majority of skin grafts lead to hypopigmented skin compared to normal uninjured skin[146]. The addition of melanocytes into skin substitutes has been effective in being able to alter the healed skin’s natural colour[147]. Therefore melanocyte incorporation provides potential in improving aesthetic outcomes in wounds healed with skin substitutes.…”

Section: Components Of a Skin Substitutementioning

confidence: 99%

Methodologies in creating skin substitutes

Nicholas

Jeschke

Amini-Nik

2016

Cell. Mol. Life Sci.

The creation of skin substitutes has significantly decreased morbidity and mortality of skin wounds. Although there are still a number of disadvantages of currently available skin substitutes, there has been a significant decline in research advances over the past several years in improving these skin substitutes. Clinically most skin substitutes used are acellular and do not use growth factors to assist wound healing, key areas of potential in this field of research. This article discusses the five necessary attributes of an ideal skin substitute. It comprehensively discusses the three major basic components of currently available skin substitutes: scaffold materials, growth factors, and cells, comparing and contrasting what has been used so far. It then examines a variety of techniques in how to incorporate these basic components together to act as a guide for further research in the field to create cellular skin substitutes with clinically better results.

Journal of Investigative Dermatology

“…Melanin pigment was visualized using Fontana–Masson staining with an eosin counterstain as described previously (Hachiya et al, 2005). …”

Section: Methodsmentioning

confidence: 99%

Variation in Hsp70-1A Expression Contributes to Skin Color Diversity

Murase

Hachiya

Fullenkamp³

et al. 2016

Self Cite

The wide range in human skin color results from varying levels of the pigment melanin. Genetic mechanisms underlying coloration differences have been explored, but identified genes do not account for all variation seen in the skin color spectrum. Post-transcriptional and post-translational regulation of factors that determine skin color, including melanin synthesis in epidermal melanocytes, melanosome transfer to keratinocytes and melanosome degradation, is also critical for pigmentation. We therefore investigated proteins that are differentially expressed in melanocytes derived from either White or African American (AA) skin. Two dimensional gel electrophoresis (2-DGE) and mass spectrometry demonstrated that Heat Shock Protein 70-1A (Hsp70-1A) protein levels were significantly higher in AA melanocytes compared to White melanocytes. Hsp70-1A expression significantly correlated with levels of tyrosinase, the rate-limiting melanogenic enzyme, consistent with a proposed role for Hsp70-family members in tyrosinase post-translational modification. Additionally, pharmacologic inhibition and siRNA-mediated down-regulation of Hsp70-1A correlated with pigmentation changes in cultured melanocytes, modified human skin substitutes and ex vivo skin. Furthermore, Hsp70-1A inhibition led to increased autophagy-mediated melanosome degradation in keratinocytes. Our data thus reveal that epidermal Hsp70-1A contributes to the diversity of skin color by regulating the amount of melanin synthesized in melanocytes and modulating autophagic melanosome degradation in keratinocytes.