β-catenin activation is necessary and sufficient to specify the dorsal dermal fate in the mouse

“Brown fat is a thermogenic or heat-producing tissue found only in eutherian mammals (Cannon and Nedergaard, 2004; Nicol et al., 1997; Rothwell and Stock, 1985).”

“…contributes to brown fat, dermis, and muscle The fate of cells that express En1 in the mouse central dermomyotome was determined with an allele of En1 with Cre recombinase coding sequences inserted (En1Cre) (Hanks et al., 1995) and the Rosa-floxed Stop-LacZ Reporter allele (RR) (Soriano, 1999).”

“Mice mutant for the myogenic transcription factor myogenin have a deficit of epaxial muscle and an excess of brown fat bundles in the cervical and interscapular region (Hasty et al., 1993).”

“…β-catenin conditional loss-of-function mutants where excision is driven by Cre expressed from the En1 locus, loss of β-catenin should occur after dermal specification in the flank. β-catenin is required within the other layer of the skin, the epidermis, for placodes to form (Huelsken et al., 2001).”

“, 2001), and β-catenin conditional gain-of-function (Harada et al., 1999) mice and embryos were genotyped as described.”

“Recently, it has been shown conclusively that the “dermatome” also contributes to fetal and postnatal epaxial skeletal muscle and to adult muscle satellite cells in both chick and mouse (Ben-Yair and Kalcheim, 2005; Gros et al., 2005; Kassar-Duchossoy et al., 2005; Relaix et al., 2005).”

“5 embryos were fixed in 4% paraformaldehyde in PBS overnight and then processed as described (Henrique et al., 1995), except that the protease treatment was 7.”

“5 day fetuses were probed for Ptch1 mRNA by whole-mount in situ hybridization to mark hair placodes (Oro et al., 1997).”

“To determine whether the specification of muscle progenitors was altered in the β-catenin mutants, we assayed muscle specification by staining for the bHLH myogenic transcription factor myogenin (Sassoon et al., 1989; Smith et al., 1994).”

“Recently, it has been shown conclusively that the “dermatome” also contributes to fetal and postnatal epaxial skeletal muscle and to adult muscle satellite cells in both chick and mouse (Ben-Yair and Kalcheim, 2005; Gros et al., 2005; Kassar-Duchossoy et al., 2005; Relaix et al., 2005).”

“Wnts are important in several earlier steps of somite and dermomyotomal development, including segmentation, somite epithelialization, dermomyotome proliferation, and expression of Pax3, Pax7, and En1 in the dermomyotome (Aulehla et al., 2003; Linker et al., 2005; Nakaya et al., 2004; Schmidt et al., 2004; Galli et al…”

“Wnts are important in several earlier steps of somite and dermomyotomal development, including segmentation, somite epithelialization, dermomyotome proliferation, and expression of Pax3, Pax7, and En1 in the dermomyotome (Aulehla et al., 2003; Linker et al., 2005; Nakaya et al., 2004; Schmidt et al., 2004; Galli et al…”

“Recently, it has been shown conclusively that the “dermatome” also contributes to fetal and postnatal epaxial skeletal muscle and to adult muscle satellite cells in both chick and mouse (Ben-Yair and Kalcheim, 2005; Gros et al., 2005; Kassar-Duchossoy et al., 2005; Relaix et al., 2005).”

“Hair follicles develop from the epidermis but their formation depends on interactions with dermis (Schmidt-Ullrich and Paus, 2005).”

“…et al., 2001; Lo Celso et al., 2004; Silva-Vargas et al., 2005), and it has been suggested that the dermal condensations participating in early stages of hair follicle development might require Wnt signal transduction (DasGupta and Fuchs, 1999; Kishimoto et al., 2000; Ridanpaa et al., 2001).”

“For immunocytochemistry, frozen sections were treated as described (Yamada et al., 1993).”

“…contributes to brown fat, dermis, and muscle The fate of cells that express En1 in the mouse central dermomyotome was determined with an allele of En1 with Cre recombinase coding sequences inserted (En1Cre) (Hanks et al., 1995) and the Rosa-floxed Stop-LacZ Reporter allele (RR) (Soriano, 1999).”

“En1Cre (Kimmel et al., 2000), En1LacZ (Loomis et al.”

“…Wnt signal transduction in the epidermis is necessary for the development of hair and feathers (Chang et al., 2004; Huelsken et al., 2001; Lo Celso et al., 2004; Silva-Vargas et al., 2005), and it has been suggested that the dermal condensations participating in early stages of hair…”

“Similarly, fetuses mutant for both Myf5 and MyoD have an excess of bundles of fat cells in the place of some epaxial muscles (Kablar et al., 2003), although it was not said if this ectopic fat is brown or white.”

“The timing of expression of En1 and Dermo1, a marker of dermal specification (Houzelstein et al., 2000; Li et al., 1995), was compared.”

“Somites segment from the anterior end of the presomitic mesoderm and form epithelial units (Pourquie, 2001).”

“…in the epidermis is necessary for the development of hair and feathers (Chang et al., 2004; Huelsken et al., 2001; Lo Celso et al., 2004; Silva-Vargas et al., 2005), and it has been suggested that the dermal condensations participating in early stages of hair follicle development might…”

“With these alleles, cells which express En1 and their progeny are marked by β-galactosidase expression (Zinyk et al., 1998).”

“The ventromedial portion of the somites become mesenchymal again to form the sclerotome and the remainder of the somite persists as an epithelial dermomyotome (Christ et al., 2004; Gossler and Hrabe de Angelis, 1998; Hirsinger et al., 2000; Scaal and Christ, 2004).”

“, 2005), Rosa-floxed Stop-LacZ Reporter (Soriano, 1999), TCF/ Lef-LacZ reporter (Liu et al., 2003), β-catenin conditional loss-of-function (Brault et al.”

“Recently, it has been shown conclusively that the “dermatome” also contributes to fetal and postnatal epaxial skeletal muscle and to adult muscle satellite cells in both chick and mouse (Ben-Yair and Kalcheim, 2005; Gros et al., 2005; Kassar-Duchossoy et al., 2005; Relaix et al., 2005).”

“, 1998), En1Cre-ER (Sgaier et al., 2005), Rosa-floxed Stop-LacZ Reporter (Soriano, 1999), TCF/ Lef-LacZ reporter (Liu et al.”

“Wnts are important in several earlier steps of somite and dermomyotomal development, including segmentation, somite epithelialization, dermomyotome proliferation, and expression of Pax3, Pax7, and En1 in the dermomyotome (Aulehla et al., 2003; Linker et al., 2005; Nakaya et al., 2004; Schmidt et al., 2004; Galli et al…”

“Similarly, fetuses mutant for both Myf5 and MyoD have an excess of bundles of fat cells in the place of some epaxial muscles (Kablar et al., 2003), although it was not said if this ectopic fat is brown or white.”

“Wnts are important in several earlier steps of somite and dermomyotomal development, including segmentation, somite epithelialization, dermomyotome proliferation, and expression of Pax3, Pax7, and En1 in the dermomyotome (Aulehla et al., 2003; Linker et al., 2005; Nakaya et al., 2004; Schmidt et al., 2004; Galli et al…”

“Wnts are important in several earlier steps of somite and dermomyotomal development, including segmentation, somite epithelialization, dermomyotome proliferation, and expression of Pax3, Pax7, and En1 in the dermomyotome (Aulehla et al., 2003; Linker et al., 2005; Nakaya et al., 2004; Schmidt et al., 2004; Galli et al…”

“, 2002), and blocking Wnts with Dkk in the chick results in a thinner dermis (Chang et al., 2004) and loss of feather follicles (our unpublished studies).”

“…segmentation, somite epithelialization, dermomyotome proliferation, and expression of Pax3, Pax7, and En1 in the dermomyotome (Aulehla et al., 2003; Linker et al., 2005; Nakaya et al., 2004; Schmidt et al., 2004; Galli et al., 2004; Capdevila et al., 1998; Fan et al., 1997; Fan and…”

“At the intermediate stage when the central dermomyotome generates dermal progenitors, it has been hypothesized, but not tested, that Wnt signaling is necessary for dermal specification (Scaal and Christ, 2004).”

“To determine whether the specification of muscle progenitors was altered in the β-catenin mutants, we assayed muscle specification by staining for the bHLH myogenic transcription factor myogenin (Sassoon et al., 1989; Smith et al., 1994).”

“The marking of dermis was more widespread and it is different from what has been observed in the fate maps of the chick central dermomyotome (Mauger, 1972; Nowicki et al., 2003; Scaal and Christ, 2004), suggesting that En1 is expressed in dermal precursors or mature dermis.”

“Wnts are expressed in the surface ectoderm (Parr et al., 1993; RodriguezNiedenfuhr et al., 2003; Schubert et al., 2002), and blocking Wnts with Dkk in the chick results in a thinner dermis (Chang et al., 2004) and loss of feather follicles (our unpublished studies).”

“Frozen sections at the forelimb level were processed for in situ hybridization (Holmes and Niswander, 2001).”

“Wnts are important in several earlier steps of somite and dermomyotomal development, including segmentation, somite epithelialization, dermomyotome proliferation, and expression of Pax3, Pax7, and En1 in the dermomyotome (Aulehla et al., 2003; Linker et al., 2005; Nakaya et al., 2004; Schmidt et al., 2004; Galli et al…”

“The expression of En1 in the central dermomyotome requires Wnts from the dorsal neural tube in the mouse (Ikeya and Takada, 1998), and from the dorsal neural tube and the surface ectoderm in the chick (Cheng et al., 2004; Olivera-Martinez et al., 2001).”

“The ventromedial portion of the somites become mesenchymal again to form the sclerotome and the remainder of the somite persists as an epithelial dermomyotome (Christ et al., 2004; Gossler and Hrabe de Angelis, 1998; Hirsinger et al., 2000; Scaal and Christ, 2004).”

“In one map of somite-derived dermis, the cells which form dermis are present first in the medial presomitic mesoderm and then later in the medial portion of epithelial somites (Cheng et al., 2004; Ordahl and Le Douarin, 1992).”

“…dermomyotome proliferation, and expression of Pax3, Pax7, and En1 in the dermomyotome (Aulehla et al., 2003; Linker et al., 2005; Nakaya et al., 2004; Schmidt et al., 2004; Galli et al., 2004; Capdevila et al., 1998; Fan et al., 1997; Fan and Tessier-Lavigne, 1994; Schmidt et al., 2004).”

“Finally, one group has found that both medial and lateral halves of the epithelial somites give rise to dermis (Ben-Yair et al., 2003).”

“Brown fat is a thermogenic or heat-producing tissue found only in eutherian mammals (Cannon and Nedergaard, 2004; Nicol et al., 1997; Rothwell and Stock, 1985).”

“Brown fat is a thermogenic or heat-producing tissue found only in eutherian mammals (Cannon and Nedergaard, 2004; Nicol et al., 1997; Rothwell and Stock, 1985).”

“…et al., 2001; Lo Celso et al., 2004; Silva-Vargas et al., 2005), and it has been suggested that the dermal condensations participating in early stages of hair follicle development might require Wnt signal transduction (DasGupta and Fuchs, 1999; Kishimoto et al., 2000; Ridanpaa et al., 2001).”

“Using genetic fate mapping under control of the homeobox transcription factor Engrailed 1 (En1), Atit et al. (2006) have shown that interscapular brown fat is derived from the paraxial mesoderm.”

“Interestingly, recent fate-mapping experiments in mice show that interscapular brown fat but not white fat arises from a population of Engrailed-1 expressing cells in the dermomyotome, a structure that also gives rise to muscle and skin (Atit et al., 2006).”

“[112], brown fat is largely produced by the paraxial mesoderm [113] , and cranial WAT from the neural crest [114] .”

“The somitic multipotent precursor population is marked by the expression of certain transcription factors, including Pax7, Engrailed-1 (En1), and the myogenic factor, Myf5 (Atit et al., 2006; Lepper and Fan, 2010; Sanchez-Gurmaches et al., 2012; Seale et al., 2008; Wang et al., 2014b) (Figure 1).”

“Hair formation Mesenchymal cells from the dorsal backskin dermis are derived from dermomyotome, in which Wnt signalling specifies their fat”

“…studies in the mouse embryo have shown that the central engrailed-positive domain of the dermomyotome contains early progenitors positive for Pax7, Pax3 and/orMyf5, which will give rise to brown fat (Atit et al., 2006; Lepper and Fan, 2010; Sanchez-Gurmaches and Guertin, 2014; Seale et al., 2008).”

“Recent data suggest that interscapular brown adipocytes derive from a common precursor that is also able to differentiate into skeletal muscle (3, 57, 63).”

“Interestingly, three distinct tissues—the dermis, muscle, and brown fat—originate from the central dermomyotome (Atit et al., 2006).”

“A lineage-tracing study found that engrailed-1–expressing (En1-expressing) cells in the central dermomyotome differentiate to BAT, skeletal muscle, and dermis (31).”

“In vivo fate-mapping has shown that progenitors derived from the central dermomyotome give rise to the interscapular brown fat cell”

“Finally, the function of Wnt/ - catenin signaling has also been studied in the skin mesenchyme by conditional loss- and gain-of-function mutations of -catenin, using an engrailed-1 cre or HoxB6 cre allele (Atit et al. 2006; Ohtola et al. 2008).”

“Classical brown fat and skeletal muscle progenitors share a common progenitor (Atit et al., 2006; Timmons et al., 2007; Seale et al., 2008; Kajimura et al., 2009), whereas precursors within both white fat depots and skeletal muscle can be recruited to express some brown fat properties (Petrovic et al.”

“required for the specification of both murine dorsal [43] and ventral [44] dermis.”

“Adipocytes within BAT depots share a common Myf5-positive precursor with myocytes [30,31].”

“5 is the stage at which BAT becomes visible in mouse embryos [23].”

“dermomyotome give rise to BAT, skeletal muscle, and dermis (30).”

“Similarly, Engrailed-1 (En1)-expressing cells in the central dermomyotome form BAT, skeletal muscle, and dermis (Atit et al., 2006).”

“The major BAT depots in mice arise from a multipotent cell population in the somites that expresses Myf5, Pax7, and En1 at early stages of development (Atit et al., 2006; Lepper and Fan, 2010; Seale et al., 2008).”

“This is consistent with lineage data obtained by using the En1Cre and En1Cre-ER KI alleles (Atit et al., 2006); En1 is expressed in the central dermomyotome and En1-expressing descendant cells give rise to the same three cell types (Atit et al., 2006).”

“…groups using different experimental approaches support the idea that brown-like adipocytes arising in predominantly white fat depots in response to cold exposure are ontogenically different from those in the classic interscapular BAT (Atit et al., 2006; Seale et al., 2008; Petrovic et al., 2010).”

“Furthermore, classical brown adipocytes develop prenatally from a dermomyotome population marked by Engrailed-1, Myf5, and Pax7, whereas beige adipocytes arise postnatally fromprogenitor populations in WAT expressing Ebf2, Pdgfra, and Sca1 (Atit et al., 2006; Lee et al., 2012b; Sanchez-Gurmaches et al., 2012; Schulz e…”

“We currently favor the idea that Myf5-expressing precursors may be more akin to the multipotential Engrailed-1expressing precursors in the central dermomyotome, which are reported to become BAT, skeletal muscle, and dermis (Atit et al., 2006).”

“Transgenic mice overexpressing Wnt10b, or a constitutively active mutant form of β-catenin, develop exuberant wound healing, dermal fibrosis, atrophy of intradermal adipose tissue and collagen accumulation in the skin (87-89).”

“Lineage-tracing experiments have indicated that BAT is derived during embryogenesis from Pax7/Myf5-expressing skeletal muscle precursors located within dermomyotome (Atit et al., 2006; Lepper and Fan, 2010; Seale et al., 2008).”

“Wnt signals appear to direct these precursor cells to the dermal fate (Atit et al. 2006).”

“A number of earlier of studies indicated that brown adipocytes share a developmental origin with skeletal muscle cells (2, 14, 35, 43) but that white and brite adipocytes do not (35, 43).”

“dermomyotome BAT positive [114,144]”

“Mammalian dermal fibroblasts are derived from multiple embryonic tissues: the head dermis derives from neural crest and paraxial mesoderm, the dorsal dermis originates from somitic mesoderm, and the ventral dermis arises from lateral plate mesoderm (Atit et al., 2006; Ohtola et al., 2008; Tran et al., 2010; Yoshida et…”

“BAT and muscle have the capacity to perform adaptive thermogenesis, and recently it has been shown that brown fat cells and muscle cells, but not white fat cells, derive from the same lineage (Atit et al., 2006; Seale et al., 2008; Timmons et al., 2007).”

“Additional studies using lineage-tracing techniques suggested that theremight be a com- mon Engrailed+ precursor that gives rise to both skeletal muscle and brown fat from a common central dermomyotome (Atit et al., 2006).”

“…# 2013 Cold Spring Harbor Laboratory Press; all rights reserved; doi: 10.1101/cshperspect.a008029 Cite this article as Cold Spring Harb Perspect Biol 2013;5:a008029 1 mesoderm and somite-derived cells to form the mesenchymal cells populating the dermis (Atit et al. 2006; Ohtola et al. 2008).”

“Dermis develops from the dermomyotome near the surface ectoderm, and its differentiation is dependent on the expression of Dermo1 and Wnt signalling from the ectoderm (Atit et al., 2006; Gensch et al., 2008; Lepper & Fan, 2010).”

“embryonic mesenchymal precursor cells expressing the transcription factor engrailed 1 (En1) were found to give rise to interscapular brown adipocytes, skeletal muscles, and dermis [53,54].”

“Although the paraxial mesoderm is commonly accepted as the primary source of brown adipocytes (Atit et al., 2006), the developmental origin(s) of subcutaneous white adipocytes are complex and are still incompletely understood.”

“It remains to be seen what happens to cell fate choices in the dermomyotome, which gives rise to brown fat derivatives [6].”

“Recently, it has been shown that brown adipocytes through involvement of PRDM16 (PR-domain-containing 16) transcription factor are derived from Myf5 positive cells which are also precursors for myogenic cells.(45,46) Bone morphogenetic protein 7 (BMP7) promotes brown adipogenesis through promoting PRDM16 expression in…”

“5 are WNT signaling responsive and express nuclear β-CATENIN.(4,22,25,31) Ectodermal WNTS are necessary for dermal WNT signaling responsiveness.”

“Lineage tracing studies revealed that interscapular BAT arises from the dermomyotome (Atit et al., 2006; Seale et al., 2008).”

“However, some researchers tend to separate white from brown adipose cells due essentially to different embryonic origins of the two cell lines (25,26,66).”

“This suggests a developmental relationship close to myocytes (Atit et al., 2006; Seale et al., 2008).”

“Brown adipocytes are derived from the dermomyotome, an engrailed 1 (EN1) (27) and myogenic factor 5 (myf5) positive cell lineage (28), which is the same lineage as that of myocytes.”

“…muscle and BAT progenitor, other groups have reported that (i) BAT and skeletal muscle are derived from a common progenitor in the dermomyotome (Atit et al., 2006), (ii) myogenin-deficient neonatal mice not only have impaired muscle development but also exhibit an accumulation of brown…”

“Lineage-tracing studies suggest that subscapular BAT and WAT are derived from distinct precursors (Atit et al., 2006; Seale et al., 2008).”

“During development, Wnt/ β-catenin are involved in the formation of the epidermis and dermis, in part due to epithelial-mesenchymal transitions [38-41].”

“paraxial mesoderm-derived structure, was permanently marked in developing mice [ 50 ].”

“5 En1+ progenitors do not appear to give rise to sBAT or any of the major white fat depots (Atit et al. 2006) (Atit personal communication) suggesting that some brown and white adipocyte origins may differ and that not all brown adipocytes share a common origin (see below).”

“5, β-catenin expression in fibroblasts is required for the formation of the dorsal and ventral dermis, while ectopic β-catenin activation increases fibroblast density and disturbs epidermal morphogenesis (Atit et al., 2006; Chen et al., 2012; Ohtola et al., 2008).”

“Because Wnt reporter activity is strong throughout the mid-gestation skin, in particular in the dermis (Atit et al., 2006) (data not shown), the tissues were understained to reveal the regions displaying the most prominent Wnt activity.”

“Recent reports suggest that skeletal muscle and brown fat share a developmental ancestry (Atit et al., 2006; Kajimura et al., 2009; Seale et al., 2008).”

“5 give rise to brown adipocytes in anterior depots (Atit et al. 2006).”

“5 dermomyotome, cells demarcated by the expression of homeobox-containing protein Engrailed-1 (EN1) originate muscle, fat and dermis (Atit et al. 2006).”

“Brown adipose tissue arises from Myf5þ precursor cells that may also produce skeletal muscle, whereas white adipose tissue develops predominantly from Myf5 precursors (Atit et al., 2006; Sgaier et al., 2005).”

“Dorsal ectoderm-derived Wnt–β-catenin signaling determines the dorsal dermal fate, but it counteracts myogenic determination [76].”

“190 Together, these results support the notion that b -catenin is required for the induction of hair placodes.”

“In addition, PRDM16 coactivates the transcriptional activity of PGC-1α, PGC-1β, PPARα, and PPARγ through direct interaction and thus drives preadipocytes development into brown adipocytes [43].”

“Rev. G. Roland, 21st century 472 Cell Stem Cell 5, November 6, 2009 ª2009 Elsevier Inc. derives from a muscle-related En1, Myf5 lineage (Atit et al., 2006; Seale et al., 2008).”