Anp32a Promotes Neuronal Regeneration after Spinal Cord Injury of Zebrafish Embryos

Abstract

After spinal cord injury (SCI) in mammals, neuronal regeneration is limited; in contrast, such regeneration occurs quickly in zebrafish. Member A of the acidic nuclear phosphoprotein 32 (Anp32a) family is involved in neuronal development, but its function is controversial, and its involvement in zebrafish SCI remains unknown. To determine the role of zebrafish Anp32a in the neuronal regeneration of SCI embryos, we microinjected Anp32a mRNA into embryos from zebrafish transgenic line Tg(mnx1:GFP) prior to SCI. Compared to control SCI embryos, the results showed that the regeneration of spinal cord and resumption of swimming capability were promoted by the overexpression of Anp32a mRNA but reduced by its knockdown. We next combined fluorescence-activated cell sorting with immunochemical staining of anti-GFAP and immunofluorescence staining against anti-PH3 on Tg(gfap:GFP) SCI embryos. The results showed that Anp32a promoted the proliferation and cell number of radial glial cells at the injury epicenter at 24 h post-injury (hpi). Moreover, when we applied BrdU labeling to SCI embryos derived from crossing the Tg(gfap:GFP) and Tg(mnx1:TagRFP) lines, we found that both radial glial cells and motor neurons had proliferated, along with their increased cell numbers in Anp32a-overexpression SCI-embryos. On this basis, we conclude that Anp32a plays a positive role in the regeneration of zebrafish SCI embryos.

Macrophage–Neuroglia Interactions in Promoting Neuronal Regeneration in Zebrafish

“…A previous study reported that radial glial cells (RGs) can promote neuronal regeneration in the CNS of zebrafish [ 67 , 68 , 69 ]. RGs in zebrafish efficiently repair lesions after injury to the telencephalon through the induction of serval processes.…”

The Promising Role of a Zebrafish Model Employed in Neural Regeneration Following a Spinal Cord Injury

“…However, even with axonal regeneration, functional recovery remains limited due to the challenges in integrating regenerative axons into existing neural circuits and reestablishing functional synaptic connections ( Figure 1 ). Zebrafish studies have already yielded valuable information on potential candidate proteins involved in neuroregeneration following SCIs, such as CTGFa [ 132 ], Cav1 [ 51 ], ANP32a [ 133 ], matrix metalloproteinase-9 [ 158 ], and sonic hedgehog [ 159 , 160 ]. Furthermore, in the current zebrafish study, differentially expressed genes were sorted and analyzed in-depth using bioinformatics methods, such as the Notch signaling pathway [ 161 , 162 ], Wnt signaling pathway [ 163 ], and Hippo-Yap/Taz signaling pathway [ 164 ].…”

“…Zeng et al (2021) found that Caveolin 1 (Cav1), a membrane protein, was significantly upregulated in the rostral side of glial cells at the injury region and was responsible for axonal regrowth [51]. Lee et al (2022) discovered that acidic nuclear phosphoprotein 32 family member A (ANP32a) played a positive role in the regeneration of zebrafish embryos with SCIs [133].…”