Voltage-activated ion channels and Ca2+-induced Ca2+ release shape Ca2+ signaling in Merkel cells

Piskorowski, Rebecca A.; Haeberle, Henry; Panditrao, Mayuri V.; Lumpkin, Ellen A.

doi:10.1007/s00424-008-0496-3

Cited by 23 publications

(64 citation statements)

References 69 publications

(103 reference statements)

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“…CD200 was also highly expressed in the dermal Schwann cells (Fig. 1F,G) that support the fibers innervating Ca V 2.1-expressing (Cacna1a -Mouse Genome Informatics) Merkel cells (Piskorowski et al, 2008) (Fig. 1E,G).…”

Section: Results and Discussion Expression Of Tbc1d10c And Cd200 Markmentioning

confidence: 66%

Identification of epidermal progenitors for the Merkel cell lineage

et al. 2010

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Epithelial stem cells in adult mammalian skin are known to maintain epidermal, follicular and sebaceous lineages during homeostasis. Recently, Merkel cell mechanoreceptors were identified as a fourth lineage derived from the proliferative layer of murine skin epithelium; however, the location of the stem or progenitor population for Merkel cells remains unknown. Here, we have identified a previously undescribed population of epidermal progenitors that reside in the touch domes of hairy skin, termed touch dome progenitor cells (TDPCs). TDPCs are epithelial keratinocytes and are distinguished by their unique co-expression of α6 integrin, Sca1 and CD200 surface proteins. TDPCs exhibit bipotent progenitor behavior as they give rise to both squamous and neuroendocrine epidermal lineages, whereas the remainder of the α6+ Sca1+ CD200– epidermis does not give rise to Merkel cells. Finally, TDPCs possess a unique transcript profile that appears to be enforced by the juxtaposition of TDPCs with Merkel cells within the touch dome niche.

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Section: Results and Discussion Expression Of Tbc1d10c And Cd200 Markmentioning

confidence: 66%

Identification of epidermal progenitors for the Merkel cell lineage

et al. 2010

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“…The recent discovery that Merkel cells express vesicular glutamate transporters further supports the presence of glutamatergic synaptic transmission (Hitchcock et al, 2004;Nunzi et al, 2004). Moreover, whole-cell recordings and live-cell imaging of dissociated Merkel cells revealed voltage-activated ion channels and depolarization-evoked Ca 2+ transients (Yamashita et al, 1992;Haeberle et al, 2004;Piskorowski et al, 2008), indicating that Merkel cells are excitable cells. Although these studies collectively suggest that Merkel cells are presynaptic cells, a direct demonstration that depolarization elicits neurotransmitter release from Merkel cells is still lacking.…”

Section: Ultrastructure Of Merkel Cellsmentioning

confidence: 98%

“…By contrast, in serum-free culture conditions, Merkel cells display actin-filled processes (Fig. 4) as well as fine, cytoplasmic tendrils (Haeberle et al, 2008).…”

Section: Do Merkel Cells Contribute To Mechanotransduction?mentioning

confidence: 99%

“…Actin-filled, dendritic processes were visualized by labeling Merkel cells with rhodamine-phalloidin (red). Details of the isolation and culture methods are given in Haeberle et al (2004 and2008).…”

Section: Conclusion and Open Questionsmentioning

confidence: 99%

“…To circumvent these challenges, Lumpkin and colleagues have developed methods to dissociate, purify and culture Merkel cells (Haeberle et al, 2004) by employing transgenic mice that specifically express green fluorescent protein (GFP) in Merkel cells in the skin (Lumpkin et al, 2003). Recent studies confirm that Merkel cells are directly activated by hypotonic-evoked cell swelling and indicate that this stimulus is transduced by Ca 2+ -permeable ion channels (Haeberle et al, 2008). …”

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Merkel Cells in Somatosensation

Haeberle

Lumpkin

2008

Chem. Percept.

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Merkel cells are rare epidermal cells whose function in the skin is still debated. These cells localize to highly touch-sensitive areas of vertebrate epithelia, including palatine ridges, touch domes and finger tips. In most cases, Merkel cells complex with somatosensory afferents to form slowly adapting touch receptors; it is unclear, however, whether mechanosensory transduction occurs in the Merkel cell, the somatosensory afferent or both. Classic anatomical results suggests that Merkel cells are sensory cells that transduce mechanical stimuli and then communicate with sensory afferents via neurotransmission. This model is supported by recent molecular, immunohistochemical and physiological studies of Merkel cells in vitro and in intact tissues. For example, Merkel cells express essential components of presynaptic machinery, including molecules required for release of the excitatory neurotransmitter glutamate. Moreover, Merkel cells in vitro and in vivo are activated by mechanical stimuli, including hypotonic-induced cell swelling. Although these findings support the hypothesis that Merkel cells are sensory receptor cells, a definitive demonstration that Merkel cells are necessary and sufficient to transduce touch awaits future studies. Keywords epidermis; mechanotransduction; somatosensory; touch Somatosensory transduction in the oral cavityAlong with the senses of taste and olfaction, the somatic senses of touch, thermoreception and pain (nociception) contribute to our ingestion and enjoyment of food. In the oral cavity, somatosensory neurons of the trigeminal, glossopharyngeal and vagal nerves encode information about the chemical and physical qualities of foodstuffs (Simon et al., 2006). For example, polymodal nociceptors innervating the tongue and palate are essential for detecting the pungent tastants found in chili peppers and wasabi (Caterina et al., 2000;Bautista et al., 2006;Kwan et al., 2006), as well as cooling agents such as menthol (Daniels and McKemy, 2007). In addition to these chemical irritants, polymodal nociceptors are activated by noxious temperatures, harsh mechanical stimuli and inflammatory mediators.The oral epithelium is also innervated by mechanosensitive neurons that monitor the positions of the tongue and foodstuffs during chewing. In the palate, at least four subtypes of somatosensory receptors have been classified as touch receptors based on morphological similarities to touch-sensitive neurons that innervate the skin. One receptor subtype, the Merkel cell-neurite complex, is particularly abundant in palatine ridges (Tachibana et al., 1997;Nunzi et al., 2004). Although the role of Merkel cell-neurite complexes in innocuous touch is well established, the function of the Merkel cell within the complex is still debated. Here, we present an historical overview of the discovery of somatosensory mechanoreceptors and review progress on the role of Merkel cells in somatosensation. This manuscript is intended to complement excellent reviews of somatosensation in the oral cavity (S...

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