Target Cells Promote the Development and Functional Maturation of Neurons Derived from a Sympathetic Precursor Cell Line

Abstract

The role of target interactions in the development and functional maturation of peripheral neurons was investigated using an immortalized sympathetic precursor cell line. bMAH cells underwent neuronal differentiation in response to neurotrophic factors, but maintained an immature neuronal phenotype characterized by small cell bodies and continued cell division. Co-culture with cardiac myocytes, a target of sympathetic innervation, promoted the appearance of large-diameter postmitotic bMAH neurons. Analysis of bMAH maturation in the presence and absence of co-cultured myocytes indicated that myocyte-derived factors promoted the survival of maturing bMAH neurons prior to their acquisition of nerve growth factor dependence. Myocyte interactions also promoted the functional maturation of bMAH neurons, leading to an increase in the localization of synaptic vesicle proteins into neuritic varicosities and the acquisition of sympathetic-like intrinsic electrical properties. Like primary sympathetic neurons, mature bMAH neurons formed functional connections to cardiac myocytes as measured by evoked postsynaptic responses in connected myocytes. The effects of myocyte co-culture on developing bMAH neurons could be mimicked by myocyte conditioned medium, indicating that cardiac myocytes produce soluble factors that promote the appearance of mature neurons. These experiments indicate that targets of innervation play a role in directing the development and final maturation of peripheral neurons.

Functional Coupling with Cardiac Muscle Promotes Maturation of hPSC-Derived Sympathetic Neurons

“…Functional connections between neurons and their target tissues are known to promote neuronal maturation during development (Bharmal et al, 2001; Devay et al, 1999). To test these, we analyzed the ability of the PHOX2B::eGFP+ neurons to release neurotransmitters when co-cultured with or without NMVM.…”

Neurotrophic Factors in Autonomic Nervous System Plasticity and Dysfunction

“…For example, IGF-1 regulates the mitotic cycle in rat sympathetic neural progenitor cells (DiCicco-Bloom and Black 1988), and is a differentiation factor for CNS stem cell-derived neuronal precursor cells (Arsenijevic and Weiss 1998), whereas epidermal growth factor (EGF) maintains sympathetic progenitor cells in a proliferative state (Silani et al 1994). CNTF induces the differentiation of sympathoadrenal precursor cells (Doering et al 1995), and an unidentified myocyte-derived neurotrophic factor promotes the survival and differentiation of sympathetic precursor cells (Bharmal et al 2001). GDNF may play a particularly important role in development of the enteric nervous system because targeted mutation of the GDNF receptor Ret results in a defect in the migration of enteric neural crest cells (Asai et al 2006).…”

Target-dependent inhibition of sympathetic neuron growth via modulation of a BMP signaling pathway

“…Once neurons recognize their appropriate targets, specific neurontarget contacts are established that involve modulation of neurite growth dynamics and the formation of functional synaptic connections (Baird et al, 1996;Mason et al, 1997;Manzini et al, 2006). Developing sympathetic neurons innervate remote targets that include the heart, pineal gland and sweat pad, and factors derived from these targets regulate neuronal growth, neurotransmitter phenotype and synaptic properties (Bharmal et al, 2001;Lockhart et al, 2000;Rowe and Parr, 1980;Cowen, 1996;Stevens and Landis, 1988;Schotzinger et al, 1994). In particular, sympathetic innervation of cardiac tissue has been well-characterized at the morphological and functional levels (Nobin 1997;Lockhart et al, 1997;Lockhart et al, 2000;Carrio 2001), providing an excellent system to examine the initial responses of developing neurons to target contact during development.…”