A New Role for TIMP-1 in Modulating Neurite Outgrowth and Morphology of Cortical Neurons

Abstract

BackgroundTissue inhibitor of metalloproteinases-1 (TIMP-1) displays pleiotropic activities, both dependent and independent of its inhibitory activity on matrix metalloproteinases (MMPs). In the central nervous system (CNS), TIMP-1 is strongly upregulated in reactive astrocytes and cortical neurons following excitotoxic/inflammatory stimuli, but no information exists on its effects on growth and morphology of cortical neurons.Principal FindingsWe found that 24 h incubation with recombinant TIMP-1 induced a 35% reduction in neurite length and significantly increased growth cones size and the number of F-actin rich microprocesses. TIMP-1 mediated reduction in neurite length affected both dendrites and axons after 48 h treatment. The effects on neurite length and morphology were not elicited by a mutated form of TIMP-1 inactive against MMP-1, -2 and -3, and still inhibitory for MMP-9, but were mimicked by a broad spectrum MMP inhibitor. MMP-9 was poorly expressed in developing cortical neurons, unlike MMP-2 which was present in growth cones and whose selective inhibition caused neurite length reductions similar to those induced by TIMP-1. Moreover, TIMP-1 mediated changes in cytoskeleton reorganisation were not accompanied by modifications in the expression levels of actin, βIII-tubulin, or microtubule assembly regulatory protein MAP2c. Transfection-mediated overexpression of TIMP-1 dramatically reduced neuritic arbour extension in the absence of detectable levels of released extracellular TIMP-1.ConclusionsAltogether, TIMP-1 emerges as a modulator of neuronal outgrowth and morphology in a paracrine and autrocrine manner through the inhibition, at least in part, of MMP-2 and not MMP-9. These findings may help us understand the role of the MMP/TIMP system in post-lesion pre-scarring conditions.

Secreted tissue inhibitor of matrix metalloproteinase restricts trans-synaptic signaling to coordinate synaptogenesis

“…Currently, there are relatively few reports concerning Timp loss in the nervous system (Crocker et al, 2004;Rivera et al, 2010). In mice, TIMP-2 knockout causes motor deficits and expanded NMJ branching (Lluri et al, 2006), and TIMP-1 overexpression reduces outgrowth in cortical cells (Ould-yahoui et al, 2009), supporting findings here. In Drosophila, Timp overexpression inhibits NMJ growth , which again complements our findings.…”

Sympathetic Neurons Express and Secrete MMP-2 and MT1-MMP to Control Nerve Sprouting via Pro-NGF Conversion

“…The New Role of TIMP-1 in Sympathetic Nerve Outgrowth As reported by Ould-yahoui et al (2009), TIMP-1 plays a crucial role in modulating neurite outgrowth and morphology of cortical neurons. We here provide first evidence, that SN express and secrete TIMP-1 to regulate nerve outgrowth in a paracrine and autocrine fashion.…”

“…Pharmacological MMP-2 inhibition was performed with a specific MMP-2 inhibitor from Calbiochem at a concentration of 1 lmol/l as described elsewhere (Ould-yahoui et al 2009). …”

“…2 MMP-2 inhibition contributes to an increase in pro-NGF amount in the cell culture supernatant. a Cell cultures of sympathetic neurons were stimulated for 48 h as described in the M&M section and MMP-2 inhibition was performed with a specific pharmacological inhibitor (1 lmol/l) as described elsewhere (Ould-yahoui et al 2009). Measured with the ELISA technique, MMP-2 inhibition resulted in an increase in pro-NGF amount in the cell-culture supernatant (n = 3).…”

“…Furthermore, a current study by Lehmann et al (2009) could show that MMP-2 is associated with the physiological process of myelination in an in vitro model of cultured dorsal root ganglia neurons. Regarding cortical neurons, in addition, a group by Ould-yahoui et al (2009) could demonstrate that MMP-2 inhibition by recombinant TIMP-1 or by a specific pharmacological inhibitor was able to reduce neurite length. Taken together, these data indicate that MMP-2 plays a crucial role in neuronal outgrowth under physiological or pathological conditions.…”