27-Hydroxycholesterol

A cholesterol metabolite with various biological roles

27-Hydroxycholesterol is a cholesterol metabolite that plays significant roles in various biological processes. It is an oxysterol, which is a type of oxidized cholesterol derivative. 27-Hydroxycholesterol is involved in the regulation of cholesterol homeostasis and has been implicated in several physiological and pathological processes.

Biosynthesis

27-Hydroxycholesterol is synthesized from cholesterol by the enzyme cholesterol 27-hydroxylase (CYP27A1), which is a member of the cytochrome P450 family. This enzyme is primarily located in the mitochondria of cells in the liver, but it is also expressed in other tissues.

Biological Functions

Cholesterol Homeostasis

27-Hydroxycholesterol is involved in the regulation of cholesterol levels in the body. It acts as a ligand for the liver X receptor (LXR), which is a nuclear receptor that regulates the expression of genes involved in cholesterol efflux, transport, and excretion.

Immune System Modulation

This oxysterol has been shown to modulate the immune system. It can influence the activity of macrophages and other immune cells, potentially affecting inflammatory responses.

Role in Disease

27-Hydroxycholesterol has been implicated in the development of several diseases, including atherosclerosis, breast cancer, and neurodegenerative diseases. Its role in these conditions is an active area of research.

Pathophysiology

Atherosclerosis

In the context of atherosclerosis, 27-hydroxycholesterol may contribute to the formation of atherosclerotic plaques by influencing cholesterol metabolism and inflammatory processes within the arterial wall.

Breast Cancer

Research suggests that 27-hydroxycholesterol may act as an estrogen receptor modulator, potentially promoting the growth of estrogen receptor-positive breast cancer cells.

Neurodegenerative Diseases

There is evidence to suggest that 27-hydroxycholesterol may be involved in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease. It may affect neuronal function and survival.

Research Directions

Ongoing research is focused on understanding the precise mechanisms by which 27-hydroxycholesterol influences various biological processes and its potential as a therapeutic target in disease.

Related pages

• Cholesterol
• Oxysterol
• Liver X receptor
• Cytochrome P450

Gallery

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  Structure of 27-Hydroxycholesterol