Melatonin deficiency and fibrous dysplasia: might a relation exist?

Area of Science:

• Endocrinology
• Bone Biology
• Genetics

Background:

• Fibrous dysplasia of bone presents in various forms, including monostotic, polystotic, McCune-Albright syndrome, and Jaffe-Lichtenstein syndrome.
• Activating mutations in the GNAS1 gene are linked to fibrous dysplasia, but cases exist without these mutations.
• Fibrous dysplastic tissue exhibits a deficiency in bone sialoprotein.

Purpose of the Study:

• To explore the potential role of melatonin deficiency in the development of fibrous dysplasia.
• To investigate the relationship between melatonin, cyclic AMP (cAMP), and bone sialoprotein expression.
• To hypothesize a mechanism linking melatonin deficiency to fibrous dysplasia and associated conditions like precocious puberty.

Main Methods:

• In vitro studies demonstrated fibrous dysplastic tissue formation induced by excess exogenous cAMP in human osteogenic cells.
• Analysis of the human bone sialoprotein gene for a RZR/ROR response element, a known melatonin receptor pathway.
• Hypothetical modeling of melatonin's effect on membrane receptors, nuclear cAMP levels, and prostaglandin E group interactions.

Main Results:

• Fibrous dysplastic tissue is characterized by a deficiency in bone sialoprotein.
• The nuclear receptor RZR/ROR for melatonin and its response element in the bone sialoprotein gene suggest a regulatory link.
• Melatonin deficiency may lead to increased cAMP in bone, potentially via prostaglandins of the E group.

Conclusions:

• Melatonin deficiency is hypothesized to play a role in the pathogenesis of fibrous dysplasia, particularly in cases lacking GNAS1 mutations.
• Altered expression of bone sialoprotein may result from changes in nuclear cAMP levels influenced by melatonin.
• Melatonin deficiency could also explain certain clinical features, such as precocious puberty in McCune-Albright syndrome.