Melanosome Processing in Keratinocytes

Byers, H. Randolph

doi:10.1002/9780470987100.ch9

Cited by 14 publications

(11 citation statements)

References 123 publications

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“…Thus, mature melanosomes formed in the basal melanocyte are transferred via its dendrites to adjacent keratinocytes (Scott 2006). On incorporation into keratinocytes, melanosomes fuse with lysosomes forming secondary lysosomes (Byers 2006). Lysosomal hydrolase degrades melanosomes as the keratinocytes move to the epidermal surface.…”

Section: Definition Classification and Basic Physicochemical Propmentioning

confidence: 99%

Interactions of iron, dopamine and neuromelanin pathways in brain aging and Parkinson's disease

Zucca

Segura‐Aguilar

Ferrari

et al. 2017

Progress in Neurobiology

544

482

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There are several interrelated mechanisms involving iron, dopamine, and neuromelanin in neurons. Neuromelanin accumulates during aging and is the catecholamine-derived pigment of the dopamine neurons of the substantia nigra and norepinephrine neurons of the locus coeruleus, the two neuronal populations most targeted in Parkinson’s disease. Many cellular redox reactions rely on iron, however an altered distribution of reactive iron is cytotoxic. In fact, increased levels of iron in the brain of Parkinson’s disease patients are present. Dopamine accumulation can induce neuronal death; however, excess dopamine can be removed by converting it into a stable compound like neuromelanin, and this process rescues the cell. Interestingly, the main iron compound in dopamine and norepinephrine neurons is the neuromelanin-iron complex, since neuromelanin is an effective metal chelator. Neuromelanin serves to trap iron and provide neuronal protection from oxidative stress. This equilibrium between iron, dopamine, and neuromelanin is crucial for cell homeostasis and in some cellular circumstances can be disrupted. Indeed, when neuromelanin-containing organelles accumulate high load of toxins and iron during aging a neurodegenerative process can be triggered. In addition, neuromelanin released by degenerating neurons activates microglia and the latter cause neurons death with further release of neuromelanin, then starting a self-propelling mechanism of neuroinflammation and neurodegeneration. Considering the above issues, age-related accumulation of neuromelanin in dopamine neurons shows an interesting link between aging and neurodegeneration.

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Section: Definition Classification and Basic Physicochemical Propmentioning

confidence: 99%

Interactions of iron, dopamine and neuromelanin pathways in brain aging and Parkinson's disease

Zucca

Segura‐Aguilar

Ferrari

et al. 2017

Progress in Neurobiology

544

482

View full text Add to dashboard Cite

show abstract

“…Maturation of melanosomes requires various membrane-trafficking factors including small Ras-like GTPases/Rab protein family members RAB- 27A, 32 and 38 (Bultema and Di Pietro, 2013). Melanin-filled melanosomes are translocated through dendrites (Scott, 2006) and transferred to neighboring keratinocytes (Byers, 2006) where they protect against ultraviolet (UV) damage and give skin its color. We have demonstrated correlation between RAB27A expression and human skin substitute pigmentation in vivo (Yoshida-Amano et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Variation in Hsp70-1A Expression Contributes to Skin Color Diversity

Murase

Hachiya

Fullenkamp³

et al. 2016

Journal of Investigative Dermatology

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The wide range in human skin color results from varying levels of the pigment melanin. Genetic mechanisms underlying coloration differences have been explored, but identified genes do not account for all variation seen in the skin color spectrum. Post-transcriptional and post-translational regulation of factors that determine skin color, including melanin synthesis in epidermal melanocytes, melanosome transfer to keratinocytes and melanosome degradation, is also critical for pigmentation. We therefore investigated proteins that are differentially expressed in melanocytes derived from either White or African American (AA) skin. Two dimensional gel electrophoresis (2-DGE) and mass spectrometry demonstrated that Heat Shock Protein 70-1A (Hsp70-1A) protein levels were significantly higher in AA melanocytes compared to White melanocytes. Hsp70-1A expression significantly correlated with levels of tyrosinase, the rate-limiting melanogenic enzyme, consistent with a proposed role for Hsp70-family members in tyrosinase post-translational modification. Additionally, pharmacologic inhibition and siRNA-mediated down-regulation of Hsp70-1A correlated with pigmentation changes in cultured melanocytes, modified human skin substitutes and ex vivo skin. Furthermore, Hsp70-1A inhibition led to increased autophagy-mediated melanosome degradation in keratinocytes. Our data thus reveal that epidermal Hsp70-1A contributes to the diversity of skin color by regulating the amount of melanin synthesized in melanocytes and modulating autophagic melanosome degradation in keratinocytes.

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“…Skin‐bleaching causes are various and complicated and encompasses cultural, aesthetic, medical, socio‐economic such as political matters . No doubt, these products have also found their application to treat skin diseases like inflammatory hyperpigmentation and melasma . Whitening agents, including corticosteroids, hydroquinone and tretinoin may, however, provoke unwanted local effects (ochronosis, irritant dermatitis, leukoderma, post‐inflammatory hyperpigmentation) and systemic toxicity (kidney and liver problems).…”

Section: Introductionmentioning

confidence: 99%

Analysis of salicylic acid, arbutin and corticosteroids in skin whitening creams available in Pakistan using chromatographic techniques

Shams

Khan

Iqbal

2016

Intern J of Cosmetic Sci

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The method results in excellent separation of skin whitening agents in cosmetic creams. The method is specific for salicylic acid, arbutin, cortisone, hydrocortisone, betamethasone valerate and betamethasone dipropionate. The calibration curve of skin whitening agents was linear with the regression analysis showed r(2) ≥ 0.999. %RSD for inter- and intraday precision were determined as 0.461 and 0.329 for salicylic acid, 0.427 and 0.317 for arbutin, 0.360 and 0.346 for cortisone, 0.336 and 0.350 for hydrocortisone, 0.463 and 0.339 for betamethasone valerate and 0.385 and 0.372 for betamethasone dipropionate, respectively. LOD and LOQ were calculated as 0.48 and 1.20 μg mL(-1) for salicylic acid, 0.09 and 0.22 μg mL(-1) for arbutin, 0.07 and 0.18 μg mL(-1) for cortisone, 0.06 and 0.24 μg mL(-1) for hydrocortisone, 0.07 and 0.20 μg mL(-1) for betamethasone valerate and 0.02 and 0.06 μg mL(-1) for betamethasone dipropionate. The recovery of skin whitening agents were 97.18% for salicylic acid, 97.99% for arbutin, 98.30% cortisone, 97.63% for hydrocortisone, 98.65% for betamethasone valerate and 98.18% for betamethasone dipropionate, respectively. According to this study, salicylic acid is present in 87.88% skin whitening creams, arbutin in 96.97%, cortisone in 60.60%, hydrocortisone in 48.48%, betamethasone valerate in 15.15% and betamethasone dipropionate present in 12.12% cosmetic creams available in Pakistan.

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Melanosome Processing in Keratinocytes

Cited by 14 publications

References 123 publications

Interactions of iron, dopamine and neuromelanin pathways in brain aging and Parkinson's disease

Interactions of iron, dopamine and neuromelanin pathways in brain aging and Parkinson's disease

Variation in Hsp70-1A Expression Contributes to Skin Color Diversity

Analysis of salicylic acid, arbutin and corticosteroids in skin whitening creams available in Pakistan using chromatographic techniques

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