毛囊干细胞的迁移性

1、 European Journal of Cell Biology 86(2007355376Hair follicle stem cells:Walking the mazeStephan Tiede a ,Jennifer E.Kloepper a,b ,Eniko Bodoa ,Sanjay Tiwari c ,Charli Kruse d ,Ralf Paus a,ÃaDepartment of Dermatology,University Hospital Schleswig-Holstein,University of Lu ¨beck,Ratzeburger

2、Allee 160,D-23538Lu ¨beck,Germany bDepartment of Molecular Medicine,Max-Planck-Institute for Biochemistry,Martinsried,Germany cDepartment of Surgery,Molecular Oncology Section,University Hospital Schleswig-Holstein,University of Kiel,Kiel,Germany dFraunhofer-Institute of Biomedical Engineering,

3、Group of Cell Differentiation and Cell Technology at the University of Lu ¨beck,Lu ¨beck,GermanyReceived 11December 2006;received in revised form 20March 2007;accepted 21March 2007Abstractr 2007Elsevier GmbH.All rights reserved.Keywords:Hair follicle;Stem cell (SC;Epithelial SC;Mesenchymal

4、 SC;Melanocyte SC;Epidermal neural crest SC;Label-retaining cells;Skin-derived precursorsBasic stem cell characteristicsIn general terms,stem cells (SCsare thought to be capable of dividing indenitely,and of giving rise to more differentiated progeny.Thus,SCs share the dening characteristics of self

5、-renewal,which maintainsÃCorresponding author.Tel.:+494515002543;fax:+494515006595.E-mail address:ralf.pausuk-sh.de (R.Paus.As a core element of their self-renewal feature,and counter-intuitive to what one might suspect at rst glance,SCs actually cycle very rarely (Bickenbach,1981;Cheng,2004.Th

6、is important,slow-cyclingproperty is utilized in pulse-chase experiments to identify the localization of SCs in various tissues:All rapidly dividing cells of a tissue incorporate nucleotide analogs such as 50-bromo-20-deoxyuridine or tritiated 3Hthymidine into newly synthesized DNA.When the label is

7、 chased,only those cells that divide rarely and still reside within the tissue over time will retain their label.It was this technique,which showed that the murine hair follicle bulge is residence to 495%of intracutaneous label-retaining cells (LRCs(Cotsarelis et al.,1990;Morris and Potten,1999;Tayl

8、or et al.,2000;Cotsarelis,2006a .Five terms are frequently used to dene the differ-entiation potential of SCs:totipotent,pluripotent,multipotent,oligopotent,and unipotent (Wagers and Weissman,2004.Cells from a fertilized oocyte,in the S.Tiede et al./European Journal of Cell Biology 86(2007355376356r

9、st few days after fertilization,are totipotent and can give rise to a fully functional organism.During the development of the embryo,the totipotent cells become specialized and are considered to be pluripotent,mean-ing they can give rise to every cell in the body but will not give rise to the placen

10、ta or supporting tissues necessary for fetal development.Pluripotent SCs be-come increasingly restricted in their lineage potential and generate tissue-specic multipotent SCs,which can give rise to the cell types from the tissue they were derived.It is still a matter of debate whether allindividual

11、SC populations in and around the hair follicle are committed to a specic differentiation(i.e., to a specic lineageor whether,given the right signal(s, all these SCs are,at least in principle,multipotent (Lavker and Sun,2000;Cotsarelis,2006b.Multipotent epithelial Stem Cells(eSCs,such as hair follicl

12、e bulge cells,have been shown to be capable of forming hair follicle,epidermis and sebaceous gland(SG(Oshima et al.,2001;Morris,2004;Blanpain and Fuchs,2006; Cotsarelis,2006b.Butat least in murine hair folliclesnestin+cells that apparently arise from the epithelial bulge,can also give rise to non-ep

13、ithelial cells like neurons or Schwann cells(Li et al.,2003;Amoh et al.,2005a,b;Hoffman, 2006(Fig.1.This remodeling event requires the presence of fully functional eSC populations,which are capable of constructing all epithelial differentiation strata.Follow-ing a period of apoptosis-driven epitheli

14、al regression (catagenand a subsequent period of relative quiescence products.Red color denotes a relativestem-ness,green color indicatesincreasing commitment towards a hair follicle-type epithelialdifferentiation pathway.Abbreviations in common use:Lhx2,LIM homeobox protein2(NM_010710;p63,tumor pro

15、teinp73-like(TP73L,NM_003722;NF k B,nuclear factor ofkappa light polypeptide gene enhancer in B-cells inhibitor,epsilon(NFKBIE,NM_518507;Wnt,wingless-type MMTVintegration site family(WNT,NM_003393;Tcf3,transcrip-tion factor3(Tcfe2a,NM_011548;Noggin,bone morphoge-netic protein4(NOG,NM_130851;Bmp,bone

16、morphogenetic protein1(BMP1,NM_006129;Rac1,ras-related C3botulinum toxin substrate1(rho family,small GTPbinding protein Rac1,AJ132695;Shh,sonic hedgehoghomolog(SHH,NM_000193.Modied after Tiede and Paus(2006.S.Tiede et al./European Journal of Cell Biology86(2007355376357(telogen,a new hair matrix,inn

17、er and outer root sheath (IRS and ORS,respectively,companion layer,and hair shaft are generated from these eSCs.This occurs during each new anagen phase under the control of an inductive,specialized mesenchyme(Cotsarelis et al., 1990;Paus and Cotsarelis,1999;Stenn and Paus,2001; Cotsarelis,2006b(Fig

18、.1.Therefore,hair follicle eSCs are programmed during hair follicle development to undergo exclusively hair follicle-type differentiation(Schmidt-Ullrich et al.,2001, 2006,but they can be re-programmed to expand into essentially all pathways of epithelial differentiation (Blanpain et al.,2004;Flinia

19、ux et al.,2004;Pearton et al.,2004,2005.This re-programming should also be possible by nuclear transfer of differentiated somatic cells into undifferentiated embryonic cells(Hochedlinger and Jaenisch,2006.Evidence for a separate population of stem cells comes from the production of pigmented hair fo

20、llicle shafts which requires intrafollicular melanogenesis.This is the specialized task of the hair follicle pigmentary unit,which is made up by neural crest-derived hair follicle melanocytes,which migrate into the hair follicle epithelium in dened developmental waves and differ-entiation patterns v

21、ia the epidermis(Peters et al.,2001. Since most,if not all,of these likely terminally differentiated pigment cells are lost during each hair follicle regression(catagen(Tobin et al.,1998;Tobin and Paus,2001;Slominski et al.,2005,a new hair follicle pigmentary unit must be cyclically regenerated duri

22、ng each anagen IIII phase before full melanin synthesis can resume again during anagen IVVI.This task is mastered by a distinct,neural crest-derived melanocyte SC(melSCpopulation,which appears to be located primarily inside of the secondary hair germ (Nishimura et al.,2002,2005,i.e.,the tiny remnant

23、 of germinativeepithelium,which is retained when mostS.Tiede et al./European Journal of Cell Biology86(2007355376 358Taken together,this introductory overview can be condensed into three key messages:(1Somatic(adultSCs of all lineages are vitallyneeded to cyclically generate pigmented hair shafts an

24、d to generate all cell populations that are required for normal function and remodeling of the hair follicle,a prototypic neuroectodermalmesodermal interaction system(Paus and Cotsarelis,1999;Stenn and Paus,2001;Schmidt-Ullrich and Paus,2005.(2These somatic SCs serve multiple additional pur-poses.Fo

25、llicular eSCs have been termedthe bone marrow of the skin(Brouard and Barrandon, 2003,while hair follicle eSCs have been demon-strated to be critical for re-epithelialization during wound healing in mouse skin.(3Developmentally programmed commitment towardsthe production of a dened,hair follicle-typ

26、e or hair follicle-related cellular progeny in vivo,suggests that hair follicle SC populations can be experimentally re-programmed and dedifferentiated in vitro,and develop a much wider range of differentiation potential after wounding/trauma in vivo.Impor-tantly,under physiological circumstances,al

27、l types of hair follicle SCs are geared towards generatingonly a limited kind of routinely produced progeny, and require special signals to divert from their restricted,lineage production activities.Hair follicle SCs are uniquely interesting targets for regenerative medicineThe ability to purify and

28、 culture autologous,adult epithelial,mesenchymal and/or neuronal hair follicle SCs from a patients own hair follicles offers fascinating therapeutic perspectives.For example,these may be exploited:(1for the preparation of skin equivalents to treat burn victims,(2for promoting the healing of large,ch

29、ronic leg ulcers,(3for the de novo generation of new human hair follicles and/or(4for gene therapy strategies,where,e.g.,inherited structural or enzymatic skin defects are to be lastingly corrected with genetically engineered,fully functional autologous hair follicle SCs, which then gradually replac

30、e the defective tissue (Ghazizadeh and Taichman,2001;Lu and Ghazizadeh, 2005;Richardson et al.,2005;Stenn and Cotsarelis, 2005;Paus,2006.Isolated hair follicle SCs could be used for generating new follicles in alopecic scalp(see(Reynolds et al., 1999;Stenn and Cotsarelis,2005,for the principle feasi

31、bility of hair follicle neogenesis in human skin, even though the practical usefulness of this approach in the management of common hair growth disorders probably is widely over-estimated(Paus,2006.Isolated murine hair follicle bulge epithelial cells induce de novo hair follicle formation after inje

32、ction into immuno-decient mice,when combined with neonatal dermal cells(Blanpain et al.,2004;Morris et al.,2004.Assembly of an appropriate epithelial platform seems to be a key prerequisite for hair follicle neogenesis(Zheng et al., 2005.Hair follicle melSCs,furthermore,may become exploitable to pre

33、vent or revert hair graying and/or to treat disguring epidermal pigmentary disorders such as vitiligo(since lost epidermal melanocytes can be replenished by amelanotic follicular melanocytes.In addition,nestin+hair follicle-associated cells(Amoh et al.,2005a,b;Hoffman,2006,which now can also be isol

34、ated and cultured from human skin and hair follicles (Kruse et al.,2006;Yu et al.,2006,hold enormous promise as a regenerative pool for innovative,cell-based treatment of neurodegenerative disorders and nerve lesions by autologous adult SCs.S.Tiede et al./European Journal of Cell Biology86(200735537

35、6359based on autoaggressive inammatory insults to the bulge region,that ultimately destroy the hair follicles regenerative capacity,could best be halted by better protection of eSCs(Paus and Foitzik,2004;Paus,2006. Tumor SCs among hair follicle SCs?By denition,SCs must be able to self-renew and prod

36、uce differentiated progeny.Asymmetric cell divi-sion can accomplish both.However,many SCs also divide symmetrically,allowing the SC population to increase in number.This type of division may be vital to development and regeneration,but may also confer the risk to develop cancer(Morrison and Kimble,2

37、006. Another related problem is,how we can best sort out prospective tumor SCs(So et al.,2006from normal adult hair follicle-related SCs that can safely be exploited, e.g.,for regenerative medicine and gene therapy purposes.This is an important issue,since several studies suggest that hair follicle

38、eSCs may not only give rise to a large variety of benign skin appendage tumors,incl.pilomatricoma and cylindroma(Massoumi et al.,2006,but also to basal cell carcinomathe most frequent human malignancy(Fan et al.,1997;Tang et al.,2004;Huntzicker et al.,2006;Oro,2006;So et al., 2006.How can we be sure

39、,that these cells never differ-entiate into function-damaging lineages(or even degen-erate malignantly,after hair follicle SCs have been removed from their natural habitat,isolated,cultured, and re-transplanted(Li and Neaves,2006? Phenotypic analyses of tumor cells in human squa-mous carcinomata of

40、head and neck have shown that cells located at the periphery of tumors share molecular signatures with eSCs(Chovanec et al.,2005;Plza k et al., 2004,2005.In normal skin,NF k B signalling is thought to inhibit squamous cell carcinoma development.NF k B activity has been shown to contribute to the sur

41、vival and growth of cultured non-tumorigenic human keratino-cytes(Ren et al.,2006and is critically involved in normal murine hair follicle development(Schmidt-Ullrich et al.,2001,2006.Many adult SC populations contain subpopulations of cells(side population,SP.Murine SP cells are mainly localized in

42、 the epidermis.Surface marker analysis revealed that sorted SP cells expressed higher levels of a6-integrin,b1-integrin,Sca-1,keratin14,and keratin 19,which are proliferating and/or progenitor cell markers,compared to non-SP cells-In addition,SP cells reportedly expressed E-cadherin,CD34,and CD71 at

43、 lower levels(Redvers et al.,2006;Terunuma et al., 2007;Yano et al.,2005.However,Triel et al.(2004, advise that these epidermal human and murine SPs lack SC characteristics.The expression of breast cancer resistance protein1(BCRP1,which participates in dye efux,was expressed at high levels at both t

44、he protein and mRNA level in SP cells.Immunohisto-chemical analysis showed that BCRP1was expressed in the basal layers and hair follicle bulge regions of mouse skin.BCRP1mRNA was found in basal layers and hair follicles of newborn skin by in situ hybridization(Yano et al.,2005.These results suggest

45、that BCRP1-positive cells represent keratinocyte SCs and SP cells,or at least cells,which are closely related to them(Lassalle et al., 2004;Yano et al.,2005.Similar results were obtained with many cancer cells:while the expression of BCRP1 may protect adult SCs from damage,it is thought to be respon

46、sible for the multidrug resistance of cancer cells (Dean et al.,2005.The cells of the bulge region display the greatest in vitro growth capacity and clonogenicity compared to cells from other regions of the hair follicle and epidermis.This suggests that these cells are multipotent. Cell fate experim

47、ents using pulse labeling of nucleotides revealed that the bulge cells give rise to lower follicles,including the ORS,matrix and medulla(Taylor et al., 2000;Tumbar et al.,2004;Ito et al.,2004. Fluorescent marking of bulge cells,employing the promoter activity of the K15gene,revealed thatbulge-derive

48、dcells were found throughout all epithelial cell types of the new lower hair follicle and hair shaft,and were also present in the epidermis and SG(Liu et al., 2003;Morris et al.,2004.Bulge cells isolated from transgenic mice containing a reporter gene and trans-planted into non-marked mice can be de

49、tected in the epidermis,hair follicles and SGs(Oshima et al.,2001. Roh et al.(2005have conrmed that the human hair follicle bulge area contains keratinocyte SCs,whereas the hair matrix represents a proliferating and differ-entiating transit-amplifying(TAcell compartment. Lyle et al.(1998showed that

50、human telogen and anagen follicles express K15and high levels of b1-integrin in the basal layer of cells surrounding the telogen club hair(secondary hair germand in the anagen bulge region,respectively.As the entire lower follicle epithelium,below the isthmus,has degenerated during the catagen phase

51、 of the hair cycle,the telogen follicles represent an enriched source of SCs.The matrix keratinocytes located at the bottom of the anagen hair bulb represent the rapidly proliferating TA cells that differentiate into all the epithelial layers of the hair follicle.These cells do not express K15,and e

52、xpress lower levels of b1-integrin than the telogen bulge(Lyle et al.,1998.Both populations form colonies.Interest-ingly,however,K15+SCs from telogen follicles formed a higher total number of colonies,and it remains unclear whether these cells originated from the bulge or the secondary hair germ.Bas

53、ed on the available data,it cannot be excluded with certainty that,under physiological conditions,hair matrix,IRS and hair shafts cells arise from a second eSC population,which has emanated from the bulge during hair follicle development,but then got deposited in the secondary hair germ with the ons

54、et of hair follicle cycling,asrst proposed by Panteleyev et al.(2001 (Kopan et al.,2002;Legue and Nicolas,2005. Molecular controls of eSC fate decisions and maintenance in the hair follicleTherefore,the transduction of certain intercellular signals,which result in growth and/or differentiation of bu

55、lge cells,must be regulated,since too few SCs in the niche may cause failure to replenish mature skin tissue or loss of hair.On the other hand,an excess of these cells may lead to excess progenitors and susceptibility to cancer.Clues to the mechanism by which the hair follicle bulge maintains a grow

56、th inhibitory environment are obtained by transcriptional proling of human and mouse hair follicle bulge cells(see following chapter summarized in Tables1and2and Figs.2and3. Most obvious transcripts,which are over-represented in the human hair follicle bulge,encode the Wnt inhibitors;WIF1(Wnt inhibi

57、tory factorand DKK3 (Dickkopf.Transcripts encoding the Wnt-inhibitors, DKK3,Dab2(Disabled-2and Sfrp1(secreted frizzled-related proteinare over-represented in the mouse hair follicle bulge.Wnt proteins are involved in organism patterning during development,as well as SC lineage determination and home

58、ostasis in the adult.The Wnt/b-catenin-Lef/Tcf pathway is activated following the binding of a soluble Wnt protein to cell surface receptors of the Frizzled family causing activation of the cytoplasmic protein dishevelled(DSH.Activated DSH prevents b-catenin degradation,allowing it to accumu-late,mi

59、grate to the nucleus,and bind to lymphoid enhancer factor/T-cell factor receptors which activate target genes that promote growth and differentiation (Logan and Nusse,2004;Reya and Clevers,2005.Over-expression of Lef-1or b-catenin in transgenic mice leads to ectopic formation of abnormal hair follicles in interfollicular and oral epithelium,while genetic abla-tion of Lef-1leads to arrested follicle deve