Zebrafish neuroglobin is a cell-membrane-penetrating globin

Area of Science:

• Neuroscience
• Biochemistry
• Cell Biology

Background:

• Neuroglobin (Ngb) is a brain-expressed heme protein involved in neuroprotection against oxidative stress.
• Human Ngb acts as a guanine nucleotide dissociation inhibitor (GDI) for G-proteins (Galphai), correlating with neuroprotection.
• Previous studies utilized protein delivery reagents like Chariot for Ngb's effects.

Purpose of the Study:

• To investigate the neuroprotective potential of a chimeric Ngb (ZHHH Ngb) in PC12 cells.
• To determine if ZHHH Ngb can enter cells independently of external delivery reagents.
• To identify the role of the zebrafish Ngb module M1 in cell membrane penetration.

Main Methods:

• Generation of chimeric ZHHH Ngb by replacing human Ngb module M1 with zebrafish Ngb module M1.
• Exposure of PC12 cells to oxidative stress and treatment with ZHHH Ngb.
• Use of fluorescein isothiocyanate (FITC)-labeled Ngb proteins to track cellular uptake.

Main Results:

• Chimeric ZHHH Ngb demonstrated neuroprotective effects against oxidative stress in PC12 cells without Chariot.
• Both zebrafish Ngb and chimeric ZHHH Ngb exhibited cell membrane penetration in the absence of Chariot.
• The zebrafish Ngb module M1 was identified as responsible for enabling cell translocation.

Conclusions:

• The zebrafish Ngb module M1 confers native cell-membrane-penetrating ability to neuroglobin.
• Chimeric ZHHH Ngb offers a promising therapeutic strategy for neuroprotection by bypassing the need for artificial delivery systems.
• This study reports the first instance of a naturally occurring cell-membrane-penetrating globin.