Chemically-induced RAT mesenchymal stem cells adopt molecular properties of neuronal-like cells but do not have basic neuronal functional properties.
Induction of adult rat bone marrow mesenchymal stem cells (MSC) by means of chemical compounds (beta-mercaptoethanol, dimethyl sulfoxide and butylated hydroxyanizole) has been proposed to lead to neuronal transdifferentiation, and this protocol has been broadly used by several laboratories worldwide. Only a few hours of MSC chemical induction using this protocol is sufficient for the acquisition of neuronal-like morphology and neuronal protein expression. However, given that cell death is abundant, we hypothesize that, rather than true neuronal differentiation, this particular protocol leads to cellular toxic effects. We confirm that the induced cells with neuronal-like morphology positively stained for NF-200, S100, beta-tubulin III, NSE and MAP-2 proteins. However, the morphological and molecular changes after chemical induction are also associated with an increase in the apoptosis of over 50% of the plated cells after 24 h. Moreover, increased intracellular cysteine after treatment indicates an impairment of redox circuitry during chemical induction, and in vitro electrophysiological recordings (patch-clamp) of the chemically induced MSC did not indicate neuronal properties as these cells do not exhibit Na(+) or K(+) currents and do not fire action potentials. Our findings suggest that a disruption of redox circuitry plays an important role in this specific chemical induction protocol, which might result in cytoskeletal alterations and loss of functional ion-gated channels followed by cell death. Despite the neuronal-like morphology and neural protein expression, induced rat bone marrow MSC do not have basic functional neuronal properties, although it is still plausible that other methods of induction and/or sources of MSC can achieve a successful neuronal differentiation in vitro.
Departamento de Fisiologia, Universidade Federal de São Paulo (UNIFESP), São Paulo, São Paulo, Brazil.
Gabriela F
GF
Barnabé
Telma T
TT
Schwindt
Maria E
ME
Calcagnotto
Fabiana L
FL
Motta
Gilberto
G
Martinez
Allan C
AC
de Oliveira
Leda M N
LM
Keim
Vânia
V
D'Almeida
Rosália
R
Mendez-Otero
Luiz E
LE
Mello
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D017209:Apoptosis; D001854:Bone Marrow Cells / Q000187:drug effects* / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D003545:Cysteine / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009930:Organic Chemicals / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects*; D051381:Rats
D009419:Nerve Tissue Proteins; D009930:Organic Chemicals; D003545:Cysteine