Transdifferentiation of rat fetal brain stem cells into penile smooth muscle cells

Abstract

OBJECTIVES To evaluate whether rat fetal brain stem cells can be induced to acquire cell fates outside the nervous system, hypothesising that cell‐based replacement therapy with stem cells can aid in the regeneration of penile smooth musculature and might help to attenuate organic erectile dysfunction (ED), as the degeneration of penile smooth muscle cells leading to subsequent impairment of function is important in organic ED. MATERIALS AND METHODS Fetal brain stem cells (FBSCs) from embryonal 12‐day Fisher 344 rats were isolated and characterized. For in vitro studies, undifferentiated FBSCs were cultured for 21 days in either N2 media (control) or N2 media conditioned in rat penile smooth muscle cell culture. These were then subjected to immunocytochemistry for specific markers of neural stem cells (nestin) and penile smooth muscle cells, i.e. α‐smooth muscle actin (αSMA), penis‐specific myosin light chain (MLC) desmin, calponin, vimentin, phosphodiesterase‐5 (PDE5) and connexin. For in vivo studies, male adult Fisher 344 rats had an intracavernous injection with saline (five rats, control) or FBSCs that were labelled genetically by an expression construct for green fluorescent protein (GFP, nine rats, experimental) and maintained for 6 weeks. The rats were then killed and penile tissue was harvested and subjected to immunocytochemistry for markers of neural stem cells, smooth muscle cells, and sinusoidal endothelium (vascular endothelial growth factor, VEGF). RESULTS Undifferentiated cells exposed to N2 media continued to maintain the characteristic morphological and protein marker features of FBSCs, while the cells exposed to the conditioned media acquired the morphological features of smooth muscle cells. In addition, the differentiated cells (30–40%) expressed smooth muscle markers. Rats implanted with FBSCs had cells that showed double‐labelling for GFP/αSMA, GFP/calponin and GFP/VEGF. The control group had no evidence of such double‐labelling. CONCLUSIONS These results suggest the transdifferentiation of FBSCs into penile smooth muscle cells. Such transdifferentiated cells showed long‐term survival when injected into the cavernous tissue, thus raising the possibility of a novel therapeutic option for organic ED.

Emerging gene and stem cell therapies for the treatment of erectile dysfunction

“…91 Similarly, when injected into corpus cavernosa if healthy 10-week old rats, human neural crest SCs have been shown to express markers of smooth muscle and vascular endothelial cells, 92 suggesting the potential for treating ED. Unfortunately, functional testing was not performed in either of these studies so the erection preserving capacity of these treatments is at this time unclear.…”

mRNA Transfection of Mouse and Human Neural Stem Cell Cultures

“…In situ, NSCs supply progenitors that differentiate into specific neuronal subtypes, depending on their anatomical location. However, neurosphere cultures have been shown to display a high degree of plasticity in their differentiation potential [5]–[8]. In addition to the subventricular zone of the brain, human neurosphere cultures can be established from more accessible neural tissues, such as the olfactory epithelium [9], or from mesenchymal and neural crest-derived stem cells in other tissues, including muscle [10], adipose [11], bone marrow [12] and the ocular limbus [13].…”

Spatial Peculiarities of Stem Cells in Plants and Animals

“…The stem cell progenitors differentiate in the adjacent peripheral zone and in the rib meristem located just beneath the CZ [13] . Yadav et al, [10] did profiling of gene expression from different cell samples of shoot apical meristems further expanded the use of this approach. They isolated three cell type populations from shoot apical meristems and demonstrated that cell-type-expression profiling is sensitive in identifying transcripts expressed in specific subsets of shoot-meristem cells [23] .…”

“…The third main characteristic is the plasticity, ability to give rise to different cell types in a culture. The stem cells in culture have the ability to differentiate into different cell types of the same germ lineage or the ability to transdifferentiate, which is the ability to differentiate into cell types across the lineage [6][7][8][9][10][11] . [12][13][14] .…”