open access

Vol 49, No 2 (2011)
Original paper
Published online: 2011-07-11
Submitted: 2011-12-19
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Involucrin, but not filaggrin and Kdap mRNA, expression is downregulated in 3-D cultures of intact rat hair bulbs after calcium stimulation

Justyna Niderla-Bielińska, Stanisław Moskalewski
DOI: 10.5603/FHC.2011.0046
·
Folia Histochem Cytobiol 2011;49(2):335-343.

open access

Vol 49, No 2 (2011)
ORIGINAL PAPERS
Published online: 2011-07-11
Submitted: 2011-12-19

Abstract

The hair follicle consists of several distinctive epidermal cell layers. The hair root, which undergoes keratinization, is surrounded by two sheaths: the inner root sheath (IRS) and the outer root sheath (ORS). The ORS is continuous with the basal layer of the epidermis. Its cells do not keratinize in situ, unlike IRS. We have previously demonstrated that keratinization of the ORS was prevented by contact with the IRS in hair follicle mid-segments (i.e. fragments dissected from skin at the level above the hair bulb and below the opening of the sebaceous gland duct) cultured on agarose layer. The purpose of this study was to determine whether the same applies to the hair bulb. After isolation, intact bulbs or hair bulb-derived cells were incubated in suspension in a low or high calcium medium. The level of mRNA for differentiation markers: involucrin, filaggrin, keratinocyte differentiation associated protein and trichohyalin, was studied by RealTime PCR. We observed increased Ca2+ upregulated expression of involucrin, filaggrin, trichohyalin and Kdap in cultures of bulb-derived cells, but in hair bulbs downregulation of involucrin and trichohyalin was observed. We concluded that the inner root sheath exerts an inhibitory effect on the expression of involucrin and trichohyalin already in the hair bulbs. The observation that downregulation of involucrin expression under Ca2+ influence occurs both in hair bulb and midsegments could simplify future experiments, since their separation does not seem to be necessary. (Folia Histochemica et Cytobiologica 2011, Vol. 49, No. 2, 335–343)

Abstract

The hair follicle consists of several distinctive epidermal cell layers. The hair root, which undergoes keratinization, is surrounded by two sheaths: the inner root sheath (IRS) and the outer root sheath (ORS). The ORS is continuous with the basal layer of the epidermis. Its cells do not keratinize in situ, unlike IRS. We have previously demonstrated that keratinization of the ORS was prevented by contact with the IRS in hair follicle mid-segments (i.e. fragments dissected from skin at the level above the hair bulb and below the opening of the sebaceous gland duct) cultured on agarose layer. The purpose of this study was to determine whether the same applies to the hair bulb. After isolation, intact bulbs or hair bulb-derived cells were incubated in suspension in a low or high calcium medium. The level of mRNA for differentiation markers: involucrin, filaggrin, keratinocyte differentiation associated protein and trichohyalin, was studied by RealTime PCR. We observed increased Ca2+ upregulated expression of involucrin, filaggrin, trichohyalin and Kdap in cultures of bulb-derived cells, but in hair bulbs downregulation of involucrin and trichohyalin was observed. We concluded that the inner root sheath exerts an inhibitory effect on the expression of involucrin and trichohyalin already in the hair bulbs. The observation that downregulation of involucrin expression under Ca2+ influence occurs both in hair bulb and midsegments could simplify future experiments, since their separation does not seem to be necessary. (Folia Histochemica et Cytobiologica 2011, Vol. 49, No. 2, 335–343)
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Keywords

hair follicle; outer root sheath; inner root sheath; hair bulb; involucrin

About this article
Title

Involucrin, but not filaggrin and Kdap mRNA, expression is downregulated in 3-D cultures of intact rat hair bulbs after calcium stimulation

Journal

Folia Histochemica et Cytobiologica

Issue

Vol 49, No 2 (2011)

Article type

Original paper

Pages

335-343

Published online

2011-07-11

DOI

10.5603/FHC.2011.0046

Bibliographic record

Folia Histochem Cytobiol 2011;49(2):335-343.

Keywords

hair follicle
outer root sheath
inner root sheath
hair bulb
involucrin

Authors

Justyna Niderla-Bielińska
Stanisław Moskalewski

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