Cerebrospinal fluid contains biologically active bone morphogenetic protein-7.

Area of Science:

• Neuroscience
• Molecular Biology
• Developmental Biology

Background:

• Bone morphogenetic proteins (BMPs) are crucial for neuronal development and function.
• The concentration and distribution of BMPs within the brain, particularly in cerebrospinal fluid (CSF), remain largely uncharacterized.

Purpose of the Study:

• To investigate the presence and biological activity of BMPs in bovine cerebrospinal fluid (CSF).
• To determine if BMP-7 in CSF can influence neuronal growth.

Main Methods:

• Western blot analysis to detect BMP-7 forms in CSF.
• Radioimmunoassay to quantify BMP-7 concentration in CSF.
• Bioassay using rat sympathetic neurons to assess CSF's effect on dendritic growth.
• Inhibition studies using follistatin and anti-BMP-7 antibodies.

Main Results:

• BMP-7 was detected in bovine CSF in both dimeric and monomeric forms.
• The concentration of BMP-7 in CSF was approximately 12 ng/ml.
• Bovine CSF induced a dose-dependent increase in sympathetic neuron dendritic growth.
• CSF-induced growth was inhibited by follistatin and BMP-7 antibodies, confirming BMP-7's role.

Conclusions:

• Bone morphogenetic protein-7 (BMP-7) is a component of normal cerebrospinal fluid (CSF).
• The concentration of BMP-7 in CSF is sufficient to elicit significant biological responses in neurons.
• This study identifies BMP-7 as a neurotrophic factor present in CSF, impacting neuronal development.