NO-induced apoptosis in human melanocytes from lightly and darkly pigmented skin.

Introduction: Nitric oxide (NO) is a potent modulator of programmed cell death, with the ability to both induce and prevent apoptosis. Some of the factors that are capable of triggering apoptosis of skin cells also cause NO overproduction in the epidermis. Unlike keratinocytes, melanin-producing melanocytes are highly resistant to apoptotic death.

The pigmentation phenotype of melanocytes affects their response to nitric oxide .

Introduction: It has been shown that nitric oxide (NO) can modulate the immune properties of epidermal melanocytes, and that overexpression of NO in the skin may contribute to inflammation-related pigmentary disorders. Little is known about whether constitutive cell pigmentation affects the sensitivity of melanocytes to NO.

Aim: To compare the effect of NO on melanin synthesis and the expression of key melanogenesis-related genes in normal human melanocytes of various degrees of constitutive pigmentation.

Differential expression of inflammatory cytokines and chemokines in lipopolysaccharide-stimulated melanocytes from lightly and darkly pigmented skin.

Increasing evidence suggests that human epidermal melanocytes play an important role in the skin immune system; however, a role of their pigmentation in immune and inflammatory responses is poorly examined. In the study, the expression of Toll-like receptor 4 (TLR4) and inflammatory cytokines and chemokines by cultured normal melanocytes derived from lightly and darkly pigmented skin was investigated after cell stimulation with lipopolysaccharide (LPS). The basal TLR4 mRNA level in heavily pigmented cells was higher as compared to their lightly pigmented counterparts.

Secretion of proinflammatory cytokines by normal human melanocytes in response to lipopolysaccharide.

A large body of evidence suggests that epidermal melanocytes are an integral part of the skin immune system and can be considered immunocompetent cells. Recently, it has been reported that human melanocytes constitutively express Toll-like receptors and may be involved in the induction of several inflammatory cytokines. In the study the secretion of IL-1β, IL-6 and TNF-α by cultured normal melanocytes was investigated after stimulation with lipopolysaccharide.

Melanin from epidermal human melanocytes: study by pyrolytic GC/MS.

Pigmentation of human skin is determined by the presence of melanin, the polymeric pigment that is produced in melanocytes and transferred to adjacent keratinocytes. Epidermal melanocytes produce two distinct types of melanin pigments: eumelanin, composed mainly of indole-type monomers, and pheomelanin that contains benzothiazine-type backbone. Eumelanin protects skin against UV-induced damages, whereas pheomelanin is believed to act as a potent UV photosensitizer and promote carcinogenesis.

[The role of neuromelanin in Parkinson's disease--new concepts].

Progressive degeneration of dopaminergic neurons of the substantia nigra and the resulting dopamine deficiency in the striatum are neuropathological basis of the movement disorders in Parkinson's disease (PD). Neuromelanin-containing neurons are particularly susceptible to degeneration and their depigmentation is the hallmark of the advanced disease. The proposed mechanisms underlaying the pathogenesis and progression of neurodegeneration in the substantia nigra include iron-catalyzed oxidative stress, mitochondrial dysfunctions, inflammation and disturbances of protein metabolism.

Alteration of growth and metabolic activity of cells in the presence of propranolol and metoprolol.

Mechanisms of action at the cellular level of a variety of drugs and xenobiotics may be assessed using Chlorella vulgaris cells. Synchronous culture, which consists of cells at the same phase of development, provides the most convenient model for studying processes at the cellular level. Stability of metabolic activity of synchronously growing cells is achieved by conducting cell culturing under strictly controlled conditions.