Developmental expression of matrix metalloproteinases 2 and 9 and their potential role in the histogenesis of the cerebellar cortex

Abstract

The development of the cerebellar cortex depends on intrinsic genetic programs and orchestrated cell-cell/cell-matrix interactions. Matrix metalloproteinases (MMPs) are proteolytic enzymes that play an important role in these interactions. MMP-2 and MMP-9 are involved in diverse neuronal functions including migration, process extension, and synaptic plasticity. We investigated the spatiotemporal pattern of expression/activity of MMP-2/MMP-9 in the developing cerebellum and their role in the histogenesis of the cerebellar cortex. The levels of transcripts of MMP-2/MMP-9 were measured with real-time quantitative polymerase chain reaction. An initial decrease in MMP-2/MMP-9 transcripts was observed between postnatal days 3 (PD3) and PD6, and the mRNA levels remained relatively constant thereafter. Zymographic analysis revealed that the expression/activity of MMP-2/MMP-9 persisted longer than their transcripts; the downregulation occurred around PD9, suggesting a mechanism of translational or post-translational regulation. The gelatinase activity was localized in the external granule layer (EGL) and the internal granule layer during PD3-PD12. The immunoreactivity of MMP-2 was mainly localized in the EGL, the Bergmann glial fibers, and the Purkinje cell layer (PCL), whereas MMP-9 immunoreactivity was detected intensively in the PCL and the extracellular space of the molecular layer. Expression of MMP-9 was relatively weak in the EGL. The immunoreactivity of MMP-2/MMP-9 became undetectable after PD21. A similar expression pattern of MMP-2/MMP-9 was observed in organotypic cerebellar slice cultures. Exposure of organotypic slices to a specific MMP-2/MMP-9 inhibitor significantly increased the thickness of the EGL and concurrently decreased the number of migrating granule neurons in the molecular layer. Thus, MMP-2 and MMP-9 play a role in the postnatal cerebellar morphogenesis.

Translocation of Synaptically Connected Interneurons across the Dentate Gyrus of the Early Postnatal Rat Hippocampus

“…Hippocampal slice explants were prepared from P5 rat pups taken from 7 litters as described previously (Ayoub et al, 2005). Briefly, animals were killed and the brains were removed quickly and placed in cold oxygenated artificial CSF [containing the following (in mM): 126.0 NaCl, 3.0 KCl, 1.3 MgSO 4 , 2.5 CaCl 2 , 1.2 NaH 2 PO 4 , 26 NaHCO 3 , 20 dextrose].…”

Human matrix metalloproteinases: An ubiquitarian class of enzymes involved in several pathological processes

“…In the last decade the role of MMP-9 in angiogenesis has represented an important matter of debate: experimental models both in vivo and in vitro have extended the original finding and are now revealing that the enzyme contribute is complex (Ahn and Brown, 2008). Even before originating a metastasis, tumor cells implanted in a mouse model attract VEGF receptor positive pro-inflammatory cells that create a niche wherein tumor cells can proliferate (Kaplan et al, 2005). MMP-9 secreted by these immune cells, by degrading basement membrane and by releasing VEGF and Kit-ligand promote recruitment of a large number of inflammatory cells that ultimately build up the niche and sustain pericytes correct positioning on newly formed blood vessels (Chantrain et al, 2004;Kaplan et al, 2005;Karroum et al, 2010;Zijlstra et al, 2006).…”

“…Even before originating a metastasis, tumor cells implanted in a mouse model attract VEGF receptor positive pro-inflammatory cells that create a niche wherein tumor cells can proliferate (Kaplan et al, 2005). MMP-9 secreted by these immune cells, by degrading basement membrane and by releasing VEGF and Kit-ligand promote recruitment of a large number of inflammatory cells that ultimately build up the niche and sustain pericytes correct positioning on newly formed blood vessels (Chantrain et al, 2004;Kaplan et al, 2005;Karroum et al, 2010;Zijlstra et al, 2006). Notably, MMP-9 modulates also vasculogenesis, helping the implant of stem cells progenitor of endothelial cells in tumor vasculature (Hiratsuka et al, 2006;Shojaei et al, 2007).…”

“…Diseases of the nervous system. In the nervous system, relatively high mRNA and protein levels of MMP-14, MMP-15, and MMP-24 and TIMP-1 and TIMP-3 are found in the perinatal rodent central nervous system (CNS) but generally decline with age (Ayoub et al, 2005;Fager and Jaworski, 2000;Jaworski, 2000;Ranasinghe et al, 2009;Rivera et al, 1997;Ulrich et al, 2005;Vaillant et al, 1999).…”

The extracellular matrix provides directional cues for neuronal migration during cerebellar development

“…Not only the expression and location of extracellular matrix molecules are modified during development, but the expression of extracellular proteases, such as MMP-2 and MMP-9, which are implicated in matrix remodeling, have been shown to be developmentally regulated in the cerebellum (19).…”