Neuritogenesis and protective effects activated by Angiotensin 1-7 in astrocytes-neuron interaction

Area of Science:

• Neuroscience
• Endocrinology
• Cell Biology

Background:

• The renin-angiotensin system (RAS) plays a role in neurological disorders.
• Astrocytes express functional receptors for RAS peptides Angiotensin-(1-7) and Angiotensin II.
• Understanding astrocyte-neuron interactions within the central nervous system (CNS) is crucial.

Purpose of the Study:

• To investigate the role of RAS peptides, specifically Angiotensin-(1-7) and Angiotensin II, in astrocyte-derived trophic factor secretion.
• To determine the effects of these factors on hippocampal neurons.
• To elucidate the biochemical mechanisms of RAS in neuron-astrocyte communication.

Main Methods:

• Primary cultures of rat hippocampal astrocytes and neurons were utilized.
• Astrocyte treatment with Angiotensin-(1-7) and Angiotensin II.
• Analysis of astrocyte modulation, including glial fibrillary acidic protein (GFAP) expression.
• Preparation of conditioned medium from treated astrocytes.
• Assessment of neurotrophic factor secretion and neuroprotective effects against excitotoxicity.

Main Results:

• Angiotensin-(1-7) treatment induced reactive astrogliosis in astrocytes, evidenced by increased GFAP expression.
• Conditioned medium from Angiotensin-(1-7)-treated astrocytes promoted neurotrophic factor secretion.
• This conditioned medium demonstrated neuroprotective effects against glutamatergic excitotoxicity.
• Angiotensin II did not induce similar beneficial effects and exacerbated deleterious effects on the brain RAS.

Conclusions:

• Angiotensin-(1-7) modulates astrocytes, enhancing neurotrophic factor secretion and providing neuroprotection.
• Angiotensin II exhibits different effects on astrocytes, potentially detrimental to brain RAS.
• Neuron-astrocyte interactions mediated by RAS are integral to CNS function and offer therapeutic targets.