Melanocytes and Their Diseases

Abstract

Human melanocytes are distributed not only in the epidermis and in hair follicles but also in mucosa, cochlea (ear), iris (eye), and mesencephalon (brain) among other tissues. Melanocytes, which are derived from the neural crest, are unique in that they produce eu-/pheomelanin pigments in unique membrane-bound organelles termed melanosomes, which can be divided into four stages depending on their degree of maturation. Pigmentation production is determined by three distinct elements: enzymes involved in melanin synthesis, proteins required for melanosome structure, and proteins required for their trafficking and distribution. Many genes are involved in regulating pigmentation at various levels, and mutations in many of them cause pigmentary disorders, which can be classified into three types: hyperpigmentation (including melasma), hypopigmentation (including oculocutaneous albinism [OCA]), and mixed hyper-/hypopigmentation (including dyschromatosis symmetrica hereditaria). We briefly review vitiligo as a representative of an acquired hypopigmentation disorder.

Bioactivities in the tamarind seed extracts: A preliminary study

“…Many systemic disorders are known to be associated with hyperpigmentation such as hemochromatosis, Wilson's disease, Gaucher's disease, Niemann-Pick's disease, amyloidosis, ochronosis, acanthosis nigricans, porphyria cutanea tarda, Addison's disease, Cushing syndrome, hyperthyroidism, pellagra, vitamin B 12 deficiency, folic acid deficiency, vagabond's disease, prurigo pigmentosa, mastocytosis, collagen diseases, liver dysfunction, and kidney dysfunction. Similarly, infectious diseases such as measles, syphilis, Malassezia furfur, von Recklinghausen's disease, Sotos syndrome, POEMS syndrome, Naegeli syndrome, Cantu syndrome, McCune-Albright syndrome, Watson syndrome, and Bloom syndrome have been linked to the process of melanogenesis (28)(29). Whereas melanin production has been established as a defense mechanism against environmental stresses, imbalance in pigment production has been linked to melanoma (6-7).…”

“…It is of two types -pheomelanin (yellow -red -light brown) and eumelanin (dark brown -black) (27). Process of melanogenesis is regulated by various factors such as the structural proteins of melanosomes, enzymes required for melanin synthesis, proteins required for melanosome transport and distribution (28) and environmental elements. Highly influenced by stress, it is regulated by stress response proteins mortalin, HSP60 and HSP70 (6).…”

A pluri- és multipotencia határán: a ganglionléc őssejtjei

“…Ugyanakkor a Sox2 fokozott kifejeződése következtében a pigmentsejtek tűnnek el az állatokból. A gliasejt, illetve melanocytasejt-fejlődési sorok tehát viszonylag könnyen átjárhatók [38,39].…”

Melanoma and Associated MicroRNAs

“…However, there are no therapies for the malignant stages of this cancer. Therefore, novel procedures are required for the development of diagnostic and prognostic strategies (7,8).…”