title: Intermittent electrical stimuli for guidance of human mesenchymal stem cell lineage commitment towards neural-like cells on electroconductive substrates.
abstract: In the context of the role of multiple physical factors in dictating stem cell fate, the present paper demonstrates the effectiveness of the intermittently delivered external electric field stimulation towards switching the stem cell fate to specific lineage, when cultured in the absence of biochemical growth factors. In particular, our findings present the ability of human mesenchymal stem cells (hMSCs) to respond to the electric stimuli by adopting extended neural-like morphology on conducting polymeric substrates. Polyaniline (PANI) is selected as the model system to demonstrate this effect, as the electrical conductivity of the polymeric substrates can be systematically tailored over a broad range (10(-9) to 10 S/cm) from highly insulating to conducting by doping with varying concentrations (10(-5) to 1 m) of HCl. On the basis of the culture protocol involving the systematic delivery of intermittent electric field (dc) stimulation, the parametric window of substrate conductivity and electric field strength was established to promote significant morphological extensions, with minimal cellular damage. A time dependent morphological change in hMSCs with significant filopodial elongation was observed after 7 days of electrically stimulated culture. Concomitant with morphological changes, a commensurate increase in the expression of neural lineage commitment markers such as nestin and βIII tubulin was recorded from hMSCs grown on highly conducting substrates, as revealed from the mRNA expression analysis using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) as well as by immune-fluorescence imaging. Therefore, the present work establishes the key role of intermittent and systematic delivery of electric stimuli as guidance cues in promoting neural-like differentiation of hMSCs, when grown on electroconductive substrates.
authors.affiliation: Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Greeshma
authors.initials: G
authors.lastname: Thrivikraman
authors.affiliation: Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Giridhar
authors.initials: G
authors.lastname: Madras
authors.affiliation: Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India. Electronic address: bikram@mrc.iisc.ernet.in.
authors.forename: Bikramjit
authors.initials: B
authors.lastname: Basu
mesh_terms: D000814:Aniline Compounds / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D002452:Cell Count; D019070:Cell Lineage / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004553:Electric Conductivity; D004558:Electric Stimulation; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D008954:Models, Biological; D064231:Nestin / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010641:Phenotype; D056951:Photoelectron Spectroscopy; D013816:Thermodynamics
chemical_list: D000814:Aniline Compounds; D015415:Biomarkers; D064231:Nestin; C416807:polyaniline
keywords: Electric field; Mesenchymal stem cells; Neural-like differentiation; Polyaniline; Substrate conductivity