The neuronal chaperone proSAAS is highly expressed in the retina

Area of Science:

• Neuroscience
• Ophthalmology
• Molecular Biology

Background:

• Neural networks require proteostatic control for protein homeostasis.
• Protein chaperones are crucial for regulating protein homeostasis.
• ProSAAS is a neuronal chaperone with anti-aggregant properties, released upon depolarization.

Purpose of the Study:

• To investigate the potential role of ProSAAS in the retina.
• To determine the expression patterns of ProSAAS in retinal cells.
• To explore the functional implications of ProSAAS in visual signaling.

Main Methods:

• Review of human and mouse retinal RNA sequencing studies.
• Single-cell sequencing analysis.
• Immunohistochemistry using ProSAAS antibodies and retinal cell markers on mouse retinal sections.
• Western blotting of mouse and human retinal extracts.

Main Results:

• ProSAAS expression is abundant in the retina, highest in retinal ganglion cells (RGCs) and horizontal cells.
• Immunohistochemistry confirmed high ProSAAS expression in RGCs and horizontal cells, localized to the ganglion cell layer and inner plexiform layer.
• Western blotting identified two processed forms of ProSAAS in mouse retinal extracts, including a 13 kDa fragment also found in human retinas.

Conclusions:

• Retinal ganglion cells and horizontal cells express high levels of ProSAAS.
• ProSAAS is present in synaptic layers of the retina.
• Data support a role for the ProSAAS chaperone in supporting visual signaling within retinal synapses.