Effects of IL‐1β, IL‐6 or LIF on rat sensory neurons co‐cultured with fibroblast‐like cells

Abstract

Inflammation may affect the local presence of sensory nerve fibers in situ and inflammatory mediators influence sensory neurons in vitro. In the present study we have investigated effects of the cytokines interleukin-1beta (IL-1beta, interleukin-6 (IL-6), and leukemia inhibitory factor (LIF) on survival of and neurite growth from neonatal rat sensory neurons co-cultured with fibroblast-like cells prepared from neonatal rat skin (sFLCs) or perichondrium (pFLCs). The results showed that both FLC types expressed receptors for all three cytokines. Five ng/ml of either cytokine, but not lower or higher concentrations, supported survival of DRG neurons co-cultured with sFLCs. Neuronal survival was also enhanced by addition of the soluble IL-6 receptor (rsIL-6R) with or without IL-6. In co-cultures with pFLCs neuronal survival was promoted by IL-6, increasing with cytokine concentration. Addition of rsIL-6R without IL-6 did also stimulate neuronal survival. The growth of neurites from DRG neurons co-cultured with sFLCs was stimulated by 0.5 ng/ml LIF, unaffected by 5 ng/ml LIF and inhibited by 50 ng/ml LIF. Considering DRG neurons co-cultured with pFLCs, 50 ng/ml of either of the three cytokines, as well as rsIL-6R conditioned medium, stimulated neurite outgrowth. Some of the cytokine effects observed were reduced by application of antibodies against nerve growth factor (NGF). We conclude that that the cytokines examined affect DRG neurons in terms of survival or neuritogenesis, that the effects are influenced by cytokine concentration and the origin of the FLCs and that some of the effects are indirect, probably being mediated by factors released from FLCs.

Developing an In Vitro Model to Screen Drugs for Nerve Regeneration

“…There is a growing interest in the development of in vitro models that can accurately simulate the natural regeneration process of neurons following a PNI. Monolayer in vitro systems have been developed by co‐culturing neurons with Schwann cells to study the influence of cell‐to‐cell interactions (Clarke et al, ), however, more complex 3D co‐culture systems have been developed to mimic the natural nerve environment more closely such as; explant cultures (Yip et al, ; Miller et al, ; Vikman et al, ; Lesuisse and Martin, ) self‐assembled aggregate cultures (Knoops et al, ; Becq et al, ; Jerregard, ; Lillesaar et al, ; Ruscheweyh and Sandkuhler, ; Edoff and Jerregard, ; Lee et al, ), and scaffold based cell cultures (Borkenhagen et al, ; Dubey et al, ; Backstrom et al, ; Balgude et al, ; Yu and Bellamkonda, ; Georgiou et al, ).…”

Absence of IL-1β positively affects neurological outcome, lesion development and axonal plasticity after spinal cord injury

“…The in vitro effects of IL-1β are very heterogeneous. IL-1β supports survival of dorsal root ganglion neurons [6] and pyramidal neurons in vitro [7], but it also induces depolarization, increases the spike frequency and enhances vulnerability of hippocampal neurons induced by N-methyl- d -aspartate receptor-mediated increase of intracellular calcium [4]. IL-1β also has strong effects on astrocytes, promoting activation, proliferation and production of neurotoxic mediators, as well as survival promoting factors [8].…”

Interleukin-1 beta and neurotrophin-3 synergistically promote neurite growth in vitro

“…In other in vitro models, IL-1β has even been seen to display beneficial effects towards neuronal survival in the CNS [10,11]. This has also been observed in axonal growth in the peripheral nervous system both in vivo following sciatic nerve injury [12,13] and in vitro in adult dorsal root ganglion (DRG) collagen gel explant cultures [14], but not in dissociated single DRG neuron cultures [15]. …”