Striking neuronal thymosin beta 4 expression in the deep layers of the mouse superior colliculus after monocular deprivation

Abstract

Thymosin beta 4 (Tβ4), a small acidic peptide isolated originally from calf thymus, is recognized as a regulator of actin polymerization. It is widely distributed in the brain, in neurons as well as in microglia, and it has been implicated in lesion-induced neuroplasticity. In the present study, we quantitatively analyzed the immunocytochemical expression pattern of Tβ4 in the superior colliculus (SC) of the adult mouse following monocular enucleation. Immunocytochemistry revealed a remarkable neuronal profile in the SC of 2, 5 and 7-week enucleated animals. We investigated the morphology, number and layer-specific localization of these immunoreactive neurons. Neuronal Tβ4-immunoreactive cell bodies were only sparsely found in the deep layers of the SC of control mice and showed only few and short immunoreactive branches, whereas their number increased significantly with post-enucleation survival time, as well as the total extent of the neuritic tree and its degree of branching. Occasionally, some Tβ4-immunoreactive neurons were also detected in the periaqueductal gray. As a regulator of actin metabolism, Tβ4 may influence the remodeling of these collicular neuronal processes, possibly in the context of a re-alignment of the sensory and motor maps in the deep SC as a consequence of the visual deprivation paradigm.

The Current Status of Somatostatin-Interneurons in Inhibitory Control of Brain Function and Plasticity

“…Cross-modal plasticity is not necessarily restricted to critical periods [ 193 ], but can also readily occur in adulthood as is observed in several species (cats: [ 194 – 196 ]; mice: [ 177 , 180 , 197 ]; rats: [ 198 ]; primates: [ 199 , 200 ]; humans: [ 201 – 203 ]). Plastic changes occurring in adulthood are generally less profound and elaborate as in the young, as vast structural remodeling, especially involving subcortical pathways, is more limited due to maturation of structural brakes, but silent corticocortical connections could become functionally unmasked [ 204 – 206 ].…”

Protective effect of Tβ4 on central nervous system tissues and its developmental prospects

“…15 It is also involved in anti-inflammatory and neurodegenerative processes, 16 especially important for the occurrence and repair of the nervous system. [17][18][19][20][21][22][23] At present, synthetic Tβ4 has been widely used in research to explore its mechanism of action in different physiological and pathological activities. Studies have found that Tβ4 messenger RNA (mRNA) is widely expressed in mammalian brains such as the hippocampus, dentate gyrus, cerebral cortex, amygdala, and some microglia.…”

The cross‐modal aspect of mouse visual cortex plasticity induced by monocular enucleation is age dependent

“…Despite being well‐documented for congenital anophthalmic subjects or animals visually deprived shortly after birth (Rauschecker et al, ; Bronchti et al, ; Laemle et al, ; Chabot et al, ; Piché et al, ; Larsen, ; Laramée et al, ; Charbonneau et al, ), research regarding cross‐modal adaptations after late‐onset and partial deprivation is rather limited (mouse: Van Brussel et al, ; He et al, ; Paulussen and Arckens, ; rat: Goel et al, ; Jitsuki et al, ; rabbit: Newton et al, ; ferret: Meredith et al, ). Monocular enucleation (ME) has been put forward as an attractive research model; it induces an irreversible loss of visual input to distinct contralateral monocular cortical target regions (mouse: Paulussen et al, ; Van Brussel et al, ; rat: Toldi et al, , , ; Chow et al, ; rabbit: Nguyen et al, ; cat: Wong‐Riley, ; Bisti and Trimarchi, ; monkey: Horton and Hocking, ; Lalonde and Chaudhuri, ; human: Steeves et al, ; Moro and Steeves, ; Hoover et al, ).…”