Plasticity in the Melanotrope Neuroendocrine Interface of &lt;i&gt;Xenopus laevis&lt;/i&gt;

Jenks, Bruce G.; Kidane, Adhanet H.; Scheenen, Wim J.J.M.; Roubos, Eric W.

doi:10.1159/000101434

Cited by 31 publications

(34 citation statements)

References 139 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this context, amphibian skin neuroendocrinology (Jackson and Reichlin, 1977;Bolaffi and Jackson, 1979;Vaudry et al, 1999;Vazquez-Martinez et al, 2003;Jenks et al, 2007Jenks et al, , 2010Slominski 2007;Slominski et al, 2008;Galas et al, 2009) promises valuable lessons for the mammalian system that may bear direct relevance for the management of human pigmentary disorders. We show that human HF organ culture and the highly hormone-sensitive HF melanocyte populations provide excellent discovery tools for elucidating ancestral, evolutionarily conserved, and clinically relevant non-classical neurohormone functions in human biology.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, in apparent contrast to amphibian skin melanophores, which are thought to require pituitary-derived signals for stimulation by TRH (Vaudry et al, 1999;VazquezMartinez et al, 2003;Jenks et al, 2007Jenks et al, , 2010, human HF melanocytes in situ are sensitive to TRH even in the absence of pituitary gland-derived melanocortins such as a-MSH. As human hair bulb epithelium expresses TRH on the gene and protein level in situ (Gáspár et al, 2010), it is conceivable www.jidonline.org 2369 that keratinocyte-derived TRH has paracrine effects on melanocytes within the human HF.…”

Section: Trh Stimulates Intrafollicular Tyrosinase Mrna Expression Anmentioning

confidence: 99%

“…On this background, it deserves emphasis that amphibian skin has long provided intriguing, yet insufficiently followed up, pointers to ancestral functions of TRH (Jackson and Reichlin, 1977;Vaudry et al, 1999;Vazquez-Martinez et al, 2003;Jenks et al, 2007Jenks et al, , 2010Galas et al, 2009). Although these have largely been ignored in human biology, TRH may still have an important role in human tissue physiology beyond the well-recognized thyrotropic function of TRH within the hypothalamic-pituitary-thyroid axis.…”

Section: Introductionmentioning

confidence: 99%

“…TRH is also recognized as a potent stimulator of pituitary proopiomelanocortin (POMC) expression and a-melanocyte-stimulating hormone (a-MSH) secretion in frogs (Vaudry et al, 1999;Jenks et al, 2007Jenks et al, , 2010. TRH derived from either the hypothalamus or the skin (Jackson and Reichlin, 1977;Vaudry et al, 1999;Galas et al, 2009) is thought to induce amphibian skin darkening indirectly by stimulating a-MSH release by the pituitary gland, inducing rapid skin darkening through melanophore stimulation (Jackson and Reichlin, 1977;Tonon et al, 1980;Vaudry et al, 1999;Vazquez-Martinez et al, 2003;Jenks et al, 2007Jenks et al, , 2010.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Thyrotropin-Releasing Hormone Selectively Stimulates Human Hair Follicle Pigmentation

Gáspár

Nguyen-Thi

Hardenbicker

et al. 2011

Journal of Investigative Dermatology

View full text Add to dashboard Cite

In amphibians, thyrotropin-releasing hormone (TRH) stimulates skin melanophores by inducing secretion of α-melanocyte-stimulating hormone in the pituitary gland. However, it is unknown whether this tripeptide neurohormone exerts any direct effects on pigment cells, namely, on human melanocytes, under physiological conditions. Therefore, we have investigated whether TRH stimulates pigment production in organ-cultured human hair follicles (HFs), the epithelium of which expresses both TRH and its receptor, and/or in full-thickness human skin in situ. TRH stimulated melanin synthesis, tyrosinase transcription and activity, melanosome formation, melanocyte dendricity, gp100 immunoreactivity, and microphthalmia-associated transcription factor expression in human HFs in a pituitary gland-independent manner. TRH also stimulated proliferation, gp100 expression, tyrosinase activity, and dendricity of isolated human HF melanocytes. However, intraepidermal melanogenesis was unaffected. As TRH upregulated the intrafollicular production of "pituitary" neurohormones (proopiomelanocortin transcription and ACTH immunoreactivity) and as agouti-signaling protein counteracted TRH-induced HF pigmentation, these pigmentary TRH effects may be mediated in part by locally generated melanocortins and/or by MC-1 signaling. Our study introduces TRH as a novel, potent, selective, and evolutionarily highly conserved neuroendocrine factor controlling human pigmentation in situ. This physiologically relevant and melanocyte sub-population-specific neuroendocrine control of human pigmentation deserves clinical exploration, e.g., for preventing or reversing hair graying.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Trh Stimulates Intrafollicular Tyrosinase Mrna Expression Anmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thyrotropin-Releasing Hormone Selectively Stimulates Human Hair Follicle Pigmentation

Gáspár

Nguyen-Thi

Hardenbicker

et al. 2011

Journal of Investigative Dermatology

View full text Add to dashboard Cite

show abstract

“…-dependent a-MSH secretion (for reviews: Jenks et al, 2003Jenks et al, , 2007Jenks et al, , 2011 Roubos et al, 2010a,b).…”

Section: þmentioning

confidence: 99%

Gene expression profiling of pituitary melanotrope cells during their physiological activation

Kuribara

Bakel

Ramekers

et al. 2011

Journal Cellular Physiology

Self Cite

View full text Add to dashboard Cite

The pituitary melanotrope cells of the amphibian Xenopus laevis are responsible for the production of the pigment-dispersing peptide α-melanophore-stimulating hormone, which allows the animal to adapt its skin color to its environment. During adaptation to a dark background the melanotrope cells undergo remarkable changes characterized by dramatic increases in cell size and secretory activity. In this study we performed microarray mRNA expression profiling to identify genes important to melanotrope activation and growth. We show a strong increase in the expression of the immediate early gene (IEG) c-Fos and of the brain-derived neurotrophic factor gene (BDNF). Furthermore, we demonstrate the involvement of another IEG in the adaptation process, Nur77, and conclude from in vitro experiments that the expression of both c-Fos and Nur77 are partially regulated by the adenylyl cyclase system and calcium ions. In addition, we found a steady up-regulation of Ras-like product during the adaptation process, possibly evoked by BDNF/TrkB signaling. Finally, the gene encoding the 105-kDa heat shock protein HSPh1 was transiently up-regulated in the course of black-background adaptation and a gene product homologous to ferritin (ferritin-like product) was >100-fold up-regulated in fully black-adapted animals. We suggest that these latter two genes are induced in response to cellular stress and that they may be involved in changing the mode of mRNA translation required to meet the increased demand for de novo protein synthesis. Together, our results show that microarray analysis is a valuable approach to identify the genes responsible for generating coordinated responses in physiologically activated cells.

show abstract

Brain distribution and evidence for both central and neurohormonal actions of cocaine‐ and amphetamine‐regulated transcript peptide in Xenopus laevis

Roubos¹,

Lázár²,

Calle³

et al. 2008

J of Comparative Neurology

Self Cite

View full text Add to dashboard Cite

We tested the hypothesis that, in the amphibian Xenopus laevis, cocaine- and amphetamine-regulated transcript peptide (CARTp) not only has widespread actions in the brain but also acts as a local factor in endocrine pituitary cells and/or is neurohemally secreted into the circulation to control peripheral targets. CARTp-immunoreactive cells occur in the olfactory bulb, nucleus accumbens, amygdala, septum, striatum, nucleus of Bellonci, ventrolateral nucleus, central thalamic nucleus, preoptic nuclei, and suprachiasmatic nucleus, and particularly in the medial pallium, ventromedial nucleus, hypothalamus, Edinger-Westphal nucleus, optic tectum, raphe nuclei, central gray, nucleus of the solitary tract, and spinal cord. From the hypothalamic magnocellular nucleus, CARTp-containing axons run to the neurohemal median eminence, and to the neural pituitary lobe to form neurohemal terminals, as shown by immunoelectron microscopy. Starvation increases the number of CARTp-cells in the optic tectum by 46% but has no effect on such cells in the torus semicircularis. CARTp does not affect in vitro release of alpha-melanophore-stimulating hormone from pituitary melanotrope cells. Our results support the hypothesis that in X. laevis, CARTp not only has multiple and not exclusively feeding-related actions in the brain but is also secreted as a neurohormone 1) into the portal system to control endocrine targets in the pituitary distal lobe and 2) from neurohemal axon terminals in the neural pituitary lobe to act peripherally. The differences in CARTp distribution between X. laevis and Rana esculenta may be related to different environmental and physiological conditions such as feeding, sensory information processing, and locomotion.

show abstract

Plasticity in the Melanotrope Neuroendocrine Interface of <i>Xenopus laevis</i>

Cited by 31 publications

References 139 publications

Thyrotropin-Releasing Hormone Selectively Stimulates Human Hair Follicle Pigmentation

Thyrotropin-Releasing Hormone Selectively Stimulates Human Hair Follicle Pigmentation

Gene expression profiling of pituitary melanotrope cells during their physiological activation

Brain distribution and evidence for both central and neurohormonal actions of cocaine‐ and amphetamine‐regulated transcript peptide in Xenopus laevis

Contact Info

Product

Resources

About