In this study, we investigated the expression and putative role of Sox9 in epidermal keratinocyte. Immunohistochemical staining showed that Sox9 is predominantly expressed in the basal layer of normal human skin epidermis, and highly expressed in several skin diseases including psoriasis, basal cell carcinoma, keratoacanthoma and squamous cell carcinoma. In calcium-induced keratinocyte differentiation model, the expression of Sox9 was decreased in a time dependent manner. When Sox9 was overexpressed using a recombinant adenovirus, cell growth was enhanced, while the expression of differentiation-related genes such as loricrin and involucrin was markedly decreased. Similarly, when rat skin was intradermally injected with the adenovirus expressing Sox9, the epidermis was thickened with increase of PCNA positive cells, while the epidermal differentiation was decreased. Finally, UVB irradiation induced Sox9 expression in cultured human epidermal keratinocytes, and keratinocytes are protected from UVB-induced apoptosis by Sox9 overexpression. Together, these results suggest that Sox9 is an important regulator of epidermal keratinocytes with putative pro-proliferation and/or pro-survival functions, and may be related to several cutaneous diseases that are characterized by abnormal differentiation and hyperproliferation.
References
[1]
Kalinin AE, Kajava AV, Steinert PM (2002) Epithelial barrier function: assembly and structural features of the cornified cell envelope. Bioessays 24: 789–800.
[2]
Hennings H, Michael D, Cheng C, Steinert P, Holbrook K, et al. (1980) Calcium regulation of growth and differentiation of mouse epidermal cells in culture. Cell 19: 245–254.
[3]
Bikle DD (2011) Vitamin D metabolism and function in the skin. Mol Cell Endocrinol 347: 80–89.
[4]
Piao MS, Choi JY, Lee DH, Yun SJ, Lee JB, et al. (2011) Differentiation-dependent expression of NADP(H):quinone oxidoreductase-1 via NF-E2 related factor-2 activation in human epidermal keratinocytes. J Dermatol Sci 62: 147–153.
[5]
Koster MI, Kim S, Mills AA, DeMayo FJ, Roop DR (2004) p63 is the molecular switch for initiation of an epithelial stratification program. Genes Dev 18: 126–131.
[6]
Nguyen BC, Lefort K, Mandinova A, Antonini D, Devgan V, et al. (2006) Cross-regulation between Notch and p63 in keratinocyte commitment to differentiation, Genes Dev. 20: 1028–1042.
[7]
Moriyama M, Durham AD, Moriyama H, Hasegawa K, Nishikawa S, et al. (2008) Multiple roles of Notch signaling in the regulation of epidermal development. Dev Cell 14: 594–604.
[8]
Rangarajan A, Talora C, Okuyama R, Nicolas M, Mammucari C, et al. (2001) Notch signaling is a direct determinant of keratinocyte growth arrest and entry into differentiation. EMBO J 20: 3427–3436.
[9]
Eckert RL, Crish JF, Efimova T, Dashti SR, Deucher A, et al. (2004) Regulation of involucrin gene expression. J Invest Dermatol 123: 13–22.
[10]
Slominski A, Wortsman J (2000) Neuroendocrinology of the skin. Endocr Rev 21: 457–487.
[11]
Slominski A, Tobin DJ, Shibahara S, Wortsman J (2004) Melanin pigmentation in mammalian skin and its hormonal regulation. Physiol Rev 84: 1155–1228.
[12]
Schepers GE, Teasdale RD, Koopman P (2002) Twenty pairs of sox: extent, homology, and nomenclature of the mouse and human sox transcription factor gene families. Dev Cell 3: 167–170.
[13]
Lefebvre V, Dumitriu B, Penzo-Méndez A, Han Y, Pallavi B (2007) Control of cell fate and differentiation by Sry-related high-mobility-group box (Sox) transcription factors. Int J Biochem Cell Biol 39: 2195–2214.
[14]
Foster JW, Dominguez-Steglich MA, Guioli S, Kwok C, Weller PA, et al. (1994) Campomelic dysplasia and autosomal sex reversal caused by mutations in an SRY-related gene. Nature 372: 525–530.
[15]
Vidal VP, Ortonne N, Schedl A (2008) Sox9 expression is a general marker of basal cell carcinoma and adnexal-related neoplasm. J Cutan Pathol 35: 373–379.
[16]
Chen W, Yang CC, Liao CY, Hung CL, Tsai SJ, et al. (2006) Expression of sex-determining genes in human seaceous glands and their possible role in the pathogenesis of acne. J Eur Acad Dermatol Venereol 20: 846–852.
[17]
Vidal VP, Chaboissier MC, Lützkendorf S, Cotsarelis G, Mill P, et al. (2005) Sox9 is essential for outer root sheath differentiation and the formation of the hair stem cell compartment. Curr Biol 15: 1340–1351.
[18]
Nowak JA, Polak L, Pasolli HA, Fuchs E (2008) Hair follicle stem cells are specified and function in early skin morphogenesis. Cell stem Cell 3: 33–43.
[19]
Seo EY, Namkung JH, Lee KM, Lee WH, Im M, et al. (2005) Analysis of calcium-inducible genes in keratinocytes using suppression subtractive hybridization and cDNA microarray. Genomics 86: 528–538.
[20]
Shi G, Sohn KC, Choi DK, Kim YJ, Kim SJ, et al. (2010) Brn2 is a transcription factor regulating keratinocyte differentiation with a possible role in the pathogenesis of lichen planus. PLoS One 5: e13216.
[21]
Shi G, Sohn KC, Choi TY, Choi DK, Lee SS, et al. (2010) Expression of paired-like homeodomain transcription factor 2c (PITX2c) in epidermal keratinocytes. Exp Cell Res 316: 3263–3271.
[22]
Missero C, Calautti E, Eckner R, Chin J, Tsai LH, et al. (1995) Involvement of the cell-cycle inhibitor Cip1/WAF1 and the E1A-associated p300 protein in terminal differentiation. Proc Natl Acad Sci USA 92: 5451–5455.
[23]
Nishi K, Inoue H, Schnier JB, Rice RH (2009) Cyclin D1 downregulation is important for permanent cell cycle exit and initiation of differentiation induced by anchorage-deprivation in human keratinocytes. J Cell Biochem 10: 63–72.
[24]
Passeron T, Valencia JC, Bertolotto C, Hoashi T, Le Pape E, et al. (2007) Sox9 is a key player in ultraviolet B-induced melanocyte differentiation and pigmentation. Proc Natl Acad Sci USA 104: 13984–13989.
[25]
Garcia-Borron JC (2007) Sox9 and the tanning response: something new under the sun. Pigment Cell Melanoma Res 21: 3–4.
[26]
Decker P, Muller S (2002) Modulating poly (ADP-ribose) polymerase activity: potential for the prevention and therapy of pathogenic situations involving DNA damage and oxidative stress. Curr Pharm Biotechnol 3: 275–283.
[27]
Yano F, Kugimiya F, Ohba S, Ikeda T, Chikuda H, et al. (2005) The canonical Wnt signaling pathway promotes chondrocyte differentiation in a Sox9-dependent manner. Biochem Biophys Res Commun 333: 1300–1308.
[28]
Blache P, van de Wetering M, Duluc I, Domon C, Berta P, et al. (2004) SOX9 is an intestine crypt transcription factor, is regulated by the Wnt pathway, and represses the CDX2 and MUC2 genes. J Cell Biol 166: 37–47.
[29]
Shi G, Sohn KC, Kim SY, Ryu EK, Park YS, et al. (2011) Sox9 increases the proliferation and colony-forming activity of outer root sheath cells cultured in vitro. Ann Dermatol 23: 138–143.
[30]
Dessinioti C, Antoniou C, Katsambas A, Stratigos AJ (2010) Basal cell carcinoma: what’s new under the sun. Photochem Photobiol 86: 481–491.
[31]
Feldman SR, Fleischer AB Jr (2011) Progression of actinic keratosis to squamous cell carcinoma revisited: clinical and treatment implications. Cutis 87: 201–207.
[32]
Iwasaki JK, Srivastava D, Moy RL, Lin HJ, Kouba DJ (2012) The molecular genetics underlying basal cell carcinoma pathogenesis and links to targeted therapeutics. J Am Acad Dermatol 66: e167–e178.
[33]
Iwai S, Yonekawa A, Harada C, Hamada M, Katagiri W, et al. (2010) Involvement of the Wnt-β-catenin pathway in invasion and migration of oral squamous carcinoma cells. Int J Oncol 37: 1095–1103.
[34]
Yoon HK, Sohn KC, Lee JS, Kim YJ, Bhak J, et al. (2008) Prediction and evaluation of protein-protein interaction in keratinocyte differentiation. Biochem Biophys Res Commun 377: 662–667.
[35]
Tollefson AE, Kuppuswamy M, Shashkova EV, Doronin K, Wold WS (2007) Preparation and titration of CsCl-banded adenovirus stocks. Methods Mol Med 130: 223–235.
