Temporal changes in prosaposin expression in the rat dentate gyrus after birth

Potential Effects of MSC-Derived Exosomes in Neuroplasticity in Alzheimer's Disease

Alzheimer’s disease (AD) is the most common type of dementia affecting regions of the central nervous system that exhibit synaptic plasticity and are involved in higher brain functions such as learning and memory. AD is characterized by progressive cognitive dysfunction, memory loss and behavioral disturbances of synaptic plasticity and energy metabolism. Cell therapy has emerged as an alternative treatment of AD. The use of adult stem cells, such as neural stem cells and Mesenchymal Stem Cells (MSCs) from bone marrow and adipose tissue, have the potential to decrease cognitive deficits, possibly by reducing neuronal loss through blocking apoptosis, increasing neurogenesis, synaptogenesis and angiogenesis. These processes are mediated primarily by the secretion of many growth factors, anti-inflammatory proteins, membrane receptors, microRNAs (miRNA) and exosomes. Exosomes encapsulate and transfer several functional molecules like proteins, lipids and regulatory RNA which can modify cell metabolism. In the proteomic characterization of the content of MSC-derived exosomes, more than 730 proteins have been identified, some of which are specific cell type markers and others are involved in the regulation of binding and fusion of exosomes with adjacent cells. Furthermore, some factors were found that promote the recruitment, proliferation and differentiation of other cells like neural stem cells. Moreover, within exosomal cargo, a wide range of miRNAs were found, which can control functions related to neural remodeling as well as angiogenic and neurogenic processes. Taking this into consideration, the use of exosomes could be part of a strategy to promote neuroplasticity, improve cognitive impairment and neural replacement in AD. In this review, we describe how exosomes are involved in AD pathology and discuss the therapeutic potential of MSC-derived exosomes mediated by miRNA and protein cargo.

Polysialylated Neural Cell Adhesion Molecule Supports Regeneration of Neurons in the Nucleus Ambiguus After Unilateral Recurrent Laryngeal Nerve Avulsion in Adult Rats

OBJECTIVES

A correlation appears to exist between the expression of the polysialic acid neural cell adhesion molecule (PSA-NCAM) and repair in central nervous system (CNS) diseases. However, the expression of PSA-NCAM in the CNS after peripheral nerve injury remains unclear. This study aimed to evaluate the expression of PSA-NCAM in the ipsilateral nucleus ambiguus (NA) after unilateral recurrent laryngeal nerve (RLN) avulsion.

MATERIALS AND METHODS

The left RLN of adult Sprague Dawley rats were avulsed. The expression of PSA-NCAM, PSA-NCAM/NeuN, and PSA-NCAM/Tuj1 in the brain stem was investigated using immunohistochemistry. The results were subjected to one-way analysis of variance followed by the Tukey post hoc test for statistical analyses.

RESULTS

PSA-NCAM-positive and PSA-NCAM/NeuN and PSA-NCAM/Tuj1 double-labeled positive cells were observed 7 days post injury in the ipsilateral NA. PSA-NCAM/NeuN and PSA-NCAM/Tuj1 double-labeled cells were observed at 21 and 7 days post injury, respectively. PSA-NCAM/NeuN double-labeled cells were also found in the contralateral NA.

CONCLUSIONS

After unilateral avulsion of the RLN, the expression of PSA-NCAM in the ipsilateral NA was correlated with the proliferation and the differentiation of neural cells. PSA-NCAM expression may be used as a predictor of the initiation of repair in neural cells.