Transcription of Melanogenesis Enzymes in Melanocytes: Dependence upon Culture Conditions and Co‐Cultivation With Keratinocytes

Abstract

Eumelanogenesis of human skin melanocytes requires at least three enzymes: tyrosinase, TRP 1, and TRP 2. The regulation of these enzymes on transcriptional level was detected in a semiquantitative attempt. The total RNA of melanocytes was reverse-transcripted and followed by a PCR with degenerated primers for all three enzymes. The amplification products were related to each other densitometrically. We examined five different culture conditions: 1) melanocytes in a popular phorbolester containing F-10-medium, 2) melanocytes in a co-culture medium with EGF, 3) melanocytes in a co-culture medium with high calcium, 4) melanocytes co-cultured with keratinocytes in EGF containing co-culture medium, and 5) melanocytes co-cultured with keratinocytes in co-culture medium with high calcium. Melanocytes cultured in phorbolester containing F-10-medium featured transcripts of tyrosinase, TRP 1, and TRP 2 in the ratio 45:45:10. The same results were obtained for melanocytes co-cultured with keratinocytes under the two different culture conditions. In melanocytes cultured alone in co-culture media only TRP 1-transcripts were present. It is likely that under co-culture conditions a keratinocyte-derived factor supports the transcription of all three enzymes. For melanocytes in the phorbolester-containing melanocyte medium a proteinkinase C dependent regulation of transcription seems possible.

Melanocyte-Stimulating Hormone Directly Enhances UV-Induced DNA Repair in Keratinocytes by a Xeroderma Pigmentosum Group A–Dependent Mechanism

“…Normal synthesis of α-MSH and ACTH is crucial for constitutive human pigmentation and the cutaneous response to UV irradiation (10, 34, 35). In addition to being the key factor in UV-induced melanogenesis, α-MSH also has crucial anti-inflammatory effects in response to UV irradiation (36, 37).…”

High‐throughput, high‐content screening for novel pigmentation regulators using a keratinocyte/melanocyte co‐culture system

“…A melanocyte/keratinocyte co‐culture system has been reported to offer advantages of mimicking a more physiologic induction of pigmentation due to the major role of keratinocytes in modulating melanocyte proliferation and differentiation . Keratinocyte‐secreted soluble factors can determine the dendriticity and cell–cell contacts of melanocytes as well as distribution patterns of melanosomes that can contribute to pigmentation . The process of melanosome transfer has been extensively studied , and the importance of a co‐culture system has been raised.…”

Melanocyte Destruction and Repigmentation in Vitiligo: A Model for Nerve Cell Damage and Regrowth

“…The presence of KCs in the vicinity of MCs is thought to play an important role in the regulation of differentiation in MCs [90]. Co-culture of MCs with KCs stimulates the transcription of melanogenesis enzymes, i.e., tyrosinase, TRP-1 and TRP-2 [59].…”