A guide to hair follicle analysis by transmission electron microscopy: technique and practice

Morioka, Kazuyuki

doi:10.1111/j.1600-0625.2009.00879.x

Cited by 29 publications

(61 citation statements)

References 34 publications

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“…Many other KAPs as well as other type I and II hair keratins are expressed primarily in the mid-to upper cortex during the advanced stage of differentiation . TEM studies of follicles have revealed the appearance of hair keratin IF bundles, i.e., proto-macrofibrils (proto-MFs), in the lower cortex (Jones and Pope, 1985;Marshall et al, 1991;Morioka, 2009;Orwin, 1979;Orwin and Woods, 1982). Small proto-MFs reported to date are around 80 nm wide and 300-700 nm long (Marshall et al, 1991;Orwin, 1979), so they are similar in size to the short IF bundles formed by the combination of K35-K85 in this study (Fig.…”

Section: Discussionsupporting

confidence: 62%

“…MFs are the hair keratin IF bundles that are observed in the cortex of hair fibers and wool by transmission electron microscopy (TEM), and have maximum lengths of approximately 10 μm (Bryson et al, 2009;Chapman and Gemmell, 1971;Jones and Pope, 1985;Marshall et al, 1991;Morioka, 2009;Orwin, 1979;Orwin and Woods, 1982;Plowman et al, 2007). In MFs, hair keratin IFs are embedded in a matrix material composed of hair keratinassociated proteins (KAPs) that link each other and to IFs .…”

Section: Introductionmentioning

confidence: 99%

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<i>In vitro</i> Assembly Properties of Human Type I and II Hair Keratins

Honda

Koike

Kubo

et al. 2014

Cell Struct. Funct.

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ABSTRACT. Multiple type I and II hair keratins are expressed in hair-forming cells but the role of each protein in hair fiber formation remains obscure. In this study, recombinant proteins of human type I hair keratins (K35, K36 and K38) and type II hair keratins (K81 and K85) were prepared using bacterial expression systems. The heterotypic subunit interactions between the type I and II hair keratins were characterized using twodimensional gel electrophoresis and surface plasmon resonance (SPR). Gel electrophoresis showed that the heterotypic complex-forming urea concentrations differ depending on the combination of keratins. K35-K85 and K36-K81 formed relatively stable heterotypic complexes. SPR revealed that soluble K35 bound to immobilized K85 with a higher affinity than to immobilized K81. The in vitro intermediate filament (IF) assembly of the hair keratins was explored by negative-staining electron microscopy. While K35-K81, K36-K81 and K35-K36-K81 formed IFs, K35-K85 afforded tight bundles of short IFs and large paracrystalline assemblies, and K36-K85 formed IF tangles. K85 promotes lateral association rather than elongation of short IFs. The in vitro assembly properties of hair keratins depended on the combination of type I and II hair keratins. Our data suggest the functional significance of K35-K85 and K36-K81 with distinct assembly properties in the formation of macrofibrils.

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Section: Discussionsupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

<i>In vitro</i> Assembly Properties of Human Type I and II Hair Keratins

Honda

Koike

Kubo

et al. 2014

Cell Struct. Funct.

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“…It is known that the interface between the Cuh and the inner root sheath cuticle (Cui) form an interlocking structure to anchor the developing hair shaft in the base of the hair follicle, which can be seen from an electron-dense aggregate structures in the outermost layer of the WT Cuh (Fig. 3 E and F) (16). This electron-dense structure is likely to be aggregated keratin filaments as it was found to show positive immunoreactivity to K82 and K32 (Fig.…”

Section: Resultsmentioning

confidence: 99%

The disruption of Sox21-mediated hair shaft cuticle differentiation causes cyclic alopecia in mice

Kiso¹,

Tanaka

Saba³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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Hair is maintained through a cyclic process that includes periodic regeneration of hair follicles in a stem cell-dependent manner. Little is known, however, about the cellular and molecular mechanisms that regulate the layered differentiation of the hair follicle. We have established a mutant mouse with a cyclic alopecia phenotype resulting from the targeted disruption of Sox21, a gene that encodes a HMG-box protein. These mice exhibit progressive hair loss after morphogenesis of the first hair follicle and become completely nude in appearance, but then show hair regrowth. Sox21 is expressed in the cuticle layer and the progenitor cells of the hair shaft in both mouse and human. The lack of this gene results in a loss of the interlocking structures required for anchoring the hair shaft in the hair follicle. Furthermore, the expression of genes encoding the keratins and keratin binding proteins in the hair shaft cuticle are also specifically down-regulated in the Sox21-null mouse. These results indicate that Sox21 is a master regulator of hair shaft cuticle differentiation and shed light on the possible causes of human hair disorders.hair follicle ͉ keratin ͉ epidermal hyperplasia

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“…It is accompanied by multiple biological processes such as a specific expression of different keratins and keratin-associated proteins (KAPs) (19) that lead, together with the reorganization of the keratin network and the loss of water, to a compaction and hardening of the fiber. However, although several complementary studies analyzed the changes in the network architecture accompanying the keratinization process (20)(21)(22), little is known about the consequence, its mechanical hardening.…”

mentioning

confidence: 99%

Keratin network modifications lead to the mechanical stiffening of the hair follicle fiber

Bornschlögl

Bildstein

Thibaut

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The complex mechanical properties of biomaterials such as hair, horn, skin, or bone are determined by the architecture of the underlying fibrous bionetworks. Although much is known about the influence of the cytoskeleton on the mechanics of isolated cells, this has been less studied in tridimensional tissues. We used the hair follicle as a model to link changes in the keratin network composition and architecture to the mechanical properties of the nascent hair. We show using atomic force microscopy that the soft keratinocyte matrix at the base of the follicle stiffens by a factor of ∼360, from 30 kPa to 11 MPa along the first millimeter of the follicle. The early mechanical stiffening is concomitant to an increase in diameter of the keratin macrofibrils, their continuous compaction, and increasingly parallel orientation. The related stiffening of the material follows a power law, typical of the mechanics of nonthermal bending-dominated fiber networks. In addition, we used X-ray diffraction to monitor changes in the (supra)molecular organization within the keratin fibers. At later keratinization stages, the inner mechanical properties of the macrofibrils dominate the stiffening due to the progressive setting up of the cystine network. Our findings corroborate existing models on the sequence of biological and structural events during hair keratinization.atomic force microscopy | elastic modulus | human hair follicle | biomechanics | X-ray diffraction B iological tissues are structurally complex materials with remarkable mechanics and elastic moduli that can range from a few pascals to several gigapascals (1-3). An active field aims at understanding how the local structural and mechanical properties of bionetworks define its macroscopic mechanics from a molecular scale toward a cellular and tissue scale (4-6). One challenge is that the properties of these networks have to be considered over multiple length and force scales with macroscopic mechanical forces being transduced from the whole tissue scale down to the cellular and molecular level and vice versa.At the cellular level, the last decades witnessed for a considerable advancement toward a better understanding of how the cytoskeleton composed of actin, microtubules, and intermediate filaments (IFs) determines cellular mechanics (1,(6)(7)(8). In vitro studies on isolated cells (6) and reconstituted in vitro bionetworks with controllable architecture and composition (9-12) considerably advanced our knowledge of cytoskeletal mechanics. However, these models are only approximations of the complex tridimensional architecture of most tissues. At the tissue level, the mechanical anisotropy together with the variety of mechanically different constituents usually hamper direct correlations between network architecture and mechanical properties (3, 13). Analytical models and computer modeling allow to theoretically link the macroscopic mechanical properties of the network with parameters of the local network architecture (5, 14, 15).The human hair follicle was used here...

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A guide to hair follicle analysis by transmission electron microscopy: technique and practice

Cited by 29 publications

References 34 publications

<i>In vitro</i> Assembly Properties of Human Type I and II Hair Keratins

<i>In vitro</i> Assembly Properties of Human Type I and II Hair Keratins

The disruption of Sox21-mediated hair shaft cuticle differentiation causes cyclic alopecia in mice

Keratin network modifications lead to the mechanical stiffening of the hair follicle fiber

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