There are two degradation systems in mammalian cells, autophagy/lysosomal pathway and ubiquitin-proteasome pathway. Proteasome is consist of multiple protein subunits and plays important roles in degradation of short-lived cellular proteins. Recent studies reveal that proteasomal degradation system is also involved in signal transduction and regulation of various cellular functions. Dysfunction or dysregulation of proteasomal function may thus be an important pathogenic mechanism in certain neurological disorders. This paper reviews the biological functions of proteasome in signal transduction and its potential roles in neurodegenerative diseases.
Inflammation has been implicated as a secondary mechanism underlying neuronal injury induced by ischemia. A variety of experimental models, including thromboembolic stroke, focal and global ischemia, have been used to evaluate contributions of inflammation to neuronal damage. The vasculature endothelium promotes inflammation through upregulation of adhesion molecules such as intercellular adhesion molecule （ICAM）, E-selectin, and P-selectin that bind to circulating leukocytes and facilitate migration of leukocytes into the central nervous system （CNS）. Once being in the CNS, leukocytes produce cytotoxic molecules that promote cell death. The response of macrophages and microglia to injury may either be beneficial by scavenging necrotic debris or be detrimental by facilitating cell death of neurons that would otherwise recover. While many studies have tested these hypotheses, the significance of inflammation in stroke models is inconclusive. This review summarizes data regarding roles of cell adhesion molecules, astrocytes, microglia and leukocytes in stroke.
The recent progress in neural stem cells （NSCs） research has shed lights on possibility of repair and restoration of neuronal function in neurodegenerative diseases using stem cells. Induction of stem cells differentiate into mature neurons is critical to achieve the clinical applications of NSCs. At present, molecular mechanisms modulating NSC differentiation are not fully understood. Differentiation of stem cells into neuronal and glial cells involves an array of changes in expression of transcription factors. Transcription factors then trigger the expression of a variety of central nervous system （CNS） genes that lead NSCs to differentiate towards different cell types. In this paper, we summarized the recent findings on the gene regulation of NSCs differentiation into neuronal cells.
