Bystin as a novel marker for reactive astrocytes in the adult rat brain following injury

Abstract

Bystin has been identified as a protein which mediates cellular interactions between trophoblastic and endometrial epithelial cells by forming complexes with two partners, trophinin and tastin, during embryo implantation. However, the presence of bystin in the central nervous system has not been demonstrated. Here, we report the cloning of the full-length cDNA of the rat bystin gene from adult brain. Immunohistochemical and RT-PCR analysis showed that the levels of bystin expression were markedly up-regulated in the both 6-hydrodopamine-lesioned rat nigrostriatum and stab-lesioned cerebral cortex in adult rats. Double immunofluorescence staining revealed that most bystin-expressing glial cells were astrocytes (immature or mature). To determine the mechanisms for the up-regulation of bystin expression in glial cells, primary cultures of postnatal cortical astrocytes were employed. Western blot analysis showed that the expression of bystin was elevated by treatment with pro-inflammatory mediators lipopolysaccharide and interleukin-1 beta. Nerve growth factor known to be released after brain injury also induced bystin expression in the cultures. Exposure of astrocyte cultures to the differentiating agent forskolin resulted in up-regulation of bystin followed by a pronounced astrocytic stellation. The results suggest that the injury in the adult brain induces spatiotemporal up-regulation of bystin and it could be influenced, at least in part, by elevation of intracellular cAMP level. Bystin expressed by reactive astrocytes may be involved in their differentiation during the inflammatory processes following brain injury. The reappearance of bystin may also indicate that some reactive astrocytes have the capacity to recapitulate early developmental stages.

Role of Gap Junction Protein Connexin43 in Astrogliosis Induced by Brain Injury

“…The other commonly used markers for reactive astrocytes include other intermediate filaments such as nestin and vimentin [11]. Some recent markers for astrogliosis include S100β, Musashi, Synemin and Bystin [73], [74], [75], [76] which are either cytoplasmic or nuclear proteins. As a membrane protein, Cx43 has an additional advantage due to its accessibility for antibody or peptide binding.…”

Zebrafish midbrain slow-amplifying progenitors exhibit high levels of transcripts for nucleotide and ribosome biogenesis

“…PML cells also express bystin transcripts that have been reported to be expressed in type B SCs and in lesioned rat cerebral cortex (Sheng et al, 2004). Prohibitin (Phb), which is often associated with cancer, is an inhibitor of cell proliferation (Mishra et al, 2006) that could potentially trigger the slowing of progenitor cell divisions.…”

Trophinin: What embryo implantation teaches us about human cancer.

“…31 Yeast bystin was identified as essential nuclear protein 1 (ENP1). 32 Bystin plays essential role in both yeast and mammals in ribosomal biogenesis and cell growth [33][34][35][36] and may play a significant role in cancer since it is a primary MYC target. 37 Bystin is also a marker of adult and embryonal stem cells.…”