Oculocutaneous albinism: Developing novel antibodies targeting the proteins associated with OCA2 and OCA4

[Oculocutaneous and ocular albinism]

Albinism can be divided into oculocutaneous albinism (OCA) and ocular albinism (OA). In the differential diagnostics these can be distinguished from rarer syndromes with partial albinism, which are frequently associated with susceptibility to infections and neurological symptoms. The OCA is an autosomal recessive inherited disease of melanin biosynthesis, which leads to complete or partial loss of melanin in the skin, hair follicles and eyes. Of the seven currently known subtypes (OCA 1-7), four are well-characterized (OCA 1-4). These are based on gene mutations, which code for tyrosinase, a key enzyme in melanin synthesis and for further proteins. These play an important role in the catalytic activity of tyrosinase and the structure and function of melanosomes. In the presence of these subtypes, the clinical symptoms and the course of the disease show a pronounced variability, especially in the type and extent of pigmentation of the skin and hair as well as the severity of eye involvement, which makes the phenotypic classification difficult. Treatment priorities are a consistent protection from UV light for prophylaxis against skin cancer and regular preventive investigations. The ocular alterations typical for albinism necessitate timely diagnostics and care by institutions specialized in ophthalmology. Novel strategies for systemic treatment of subtypes of albinism are in preclinical testing. The OA without skin involvement shows X‑linked inheritance, is much rarer and is characterized by reduced pigmentation of the retina and iris, nystagmus and macular hypoplasia, sometimes with substantial loss of visual acuity. The typical ocular symptoms of OA can be manifested to a varying extent in all forms of OCA.

MITF-M regulates melanogenesis in mouse melanocytes

BACKGROUND

Although the impact of the microphthalamia-associated transcription factor (Mitf) signaling pathway on melanocytes progression has been extensively studied, the specific molecular mechanisms behind MITF-M-enhanced melanin production in melanocytes still need to be clarified.

METHODS

In this study, we analyzed the levels of Mitf-M in skin tissues of different coat mice in order to further reveal the relationship between Mitf-M and skin pigmentation. To address the function of Mitf-M on melanogenesis, we have used an overexpression system and combined morphological and biochemical methods to investigate its localization in different coat color mice and pigmentation-related genes' expression in mouse melanocytes.

RESULTS

The qRT-PCR assay and Western blotting analysis revealed that Mitf-M mRNA and protein were synthesized in all tested mice skin samples, with the highest expression level in brown skin, a moderate expression level in grey skin and the lowest expression level in black skin. Simultaneously, immunofluorescence staining revealed that MITF-M was mainly expressed in the hair follicle matrix and inner and outer root sheath in the skin tissues with different coat colors. Furthermore, overexpression of MITF-M led to increased melanin content and variable pigmentation-related gene expression.

CONCLUSION

These results directly demonstrate that MITF-M not only influences melanogenesis, but also determines the progression of melanosomal protein in mouse melanocytes.