Differentially expressed gene networks in cultured smooth muscle cells from normal and neuropathic bladder

Abstract

Neuropathic bladder dysfunction results from abnormal development of the spine, spinal cord injuries, or diseases such as diabetics. Patients with neuropathic bladders often require surgical intervention such as bladder reconstruction to improve incontinence and prevent renal damage. Tissue engineering with ex-vivo cultured bladder cells has been suggested as one means for improving bladder function. However, we previously demonstrated that cultured bladder smooth muscle cells (SMCs) derived from neuropathic bladder exhibit and maintain altered pathologic phenotypes in culture. To identify genes that are responsible for the abnormal neuropathic phenotypes specifically elevated cell proliferation, the expression levels of 1,185 genes were compared between cultured SMCs derived from normal and neuropathic bladders using a cDNA array consisting of well-annotated genes. The expression data were analyzed using several methods to identify differentially expressed genes. The resulting sets of differentially expressed genes were examined by pathway analysis to identify the networks that remain abnormal in the culture-stable phenotype of neuopathic SMCs. A total of 18 genes that are differentially expressed between cultured normal and neuropathic bladder SMCs were identified. Of these 17 were up-regulated greater than 2-fold in neuropathic bladder SMCs, six of them along with one gene that was not upregulated greater than 2-fold in cultured neuropathic bladder SMCs were confirmed and identified by more stringent analysis methods including significance analysis of microarrays, class comparison, and class prediction analyses. The major dysregulated pathways include fibroblast growth factor signaling, PTEN signaling, and integrin signaling. Our results further suggest that altered neuropathic bladder SMC phenotypes is stable in the culture environments and that SMCs derived from diseased bladders may not be appropriate for tissue engineering purpose without modification of pathologically altered genes expression.

Integrin αv Mediates Contractility Whereas Integrin α4 Regulates Proliferation of Human Bladder Smooth Muscle Cells via FAK Pathway under Physiological Stretch

“…11 Although previous research showed that integrin subunits in BSMCs were up-regulated in response to over stretch injury, 12 to our knowledge it remained unknown which integrin subunit changes under physiological stretch. Data from the current study clearly reveal that the expression of integrin a4 and integrin av was largely increased but integrin subunits a1, a3, a4, av, b1 and b3 were not affected under physiological stretch.…”

Adipose Derived Stem Cells and Smooth Muscle Cells: Implications for Regenerative Medicine

“…A restriction to date has been a reliable source of healthy SMCs, as biopsies normally lead to low cell harvest that needs to be expanded at length before therapeutic use [10]. In addition, previous research has shown that SMCs that are obtained from diseased tissue can differ phenotypically and functionally from normal healthy SMCs, which consequently restricts their use [52,53]. The findings of Rodriguez et al (2006) [10], Jack et al (2009) [42], Kima et al (2008) [45] and Yang et al (2008) [46] describe a source of cells to use for SMC applications, as the results show that ADSCs have the potential to differentiate into functional SMCs and consequently may prove a useful source of autologous cells for reconstruction of diseased human organs and tissues containing smooth muscle.…”

Stem Cells in Functional Bladder Engineering

“…However, several issues currently limit their applicability. Beside their restricted proliferation ability and the loss of contractile phenotype during in vitro culture and expansion [56], there are many obstacles associated with utilizing patients' own SMCs, such as sample size limitation and pathological changes [18,57]. Thus, to overcome these constraints, adult [58], embryonic (ESCs) [59] and induced pluripotent stem cells (iPSCs) [60] have been considered potential candidates for detrusor muscle bioengineering.…”

“…However, the use of primary cells is often limited by their short life span, and they cannot be isolated from diseased tissue, for example urothelial progenitors from bladder cancer patients or smooth muscle cells (SMCs) from neuropathic bladders [17,18]. Based on their ability for multilineage differentiation, plasticity, migration and self-renewal, stem cells are being considered suitable candidates to further improve tissue regeneration and to facilitate faster incorporation of transplanted bioscaffolds into the native tissue without the primary cell drawbacks [19,20].…”