Increased metalloproteinase activity in the hippocampus following status epilepticus
Introduction
Epilepsy prevention in high-risk patients has been a challenging problem. Drugs that effectively treat spontaneous seizures have been ineffective in preventing epilepsy. One reason may be that most anti-epileptic drugs dampen excitation or increase inhibition without focusing on the molecular and cellular changes that contribute to the development of epilepsy. Previously we published in a rodent model of epilepsy that perineuronal net (PNN) integrity is lost as animals develop epilepsy and remains diminished in animals with chronic epilepsy (McRae et al., 2012). The loss of the PNN may apply to other brain disorders such as stroke and schizophrenia (Karetko-Sysa et al., 2011, Mauney et al., 2013). The PNN is a multimeric proteoglycan complex that surrounds synapses on the cell body and proximal dendrites and is especially abundant around fast spiking-parvalbumin (FS-PV) interneurons.
The main components of the PNN are hyaluronic acid (HA), hyaluronan synthases (HASs), chondroitin sulfate proteoglycans − primarily lecticans, HA and proteoglycan link protein (HAPLNs), and tenascin-R (Galtrey et al., 2008, Carulli et al., 2010, Kwok et al., 2010, Giamanco and Matthews, 2012). Aggrecan is a PNN specific lectican, having several protein domains for cross linking to tenascin and HA and long stretches of chondroitin sulfate side chains. Hyaluronic acid is synthesized and remains attached to the plasma membrane by HASs (McRae and Porter, 2012). The PNN appears during the 2nd week of postnatal development and its components continue to increase throughout adulthood (McRae et al., 2010). The PNN has multiple functions, including neurotransmitter receptor synaptic stabilization, closing of the ocular dominance sensitive period, and neuroprotection (Cabungcal et al., 2013, Maroto et al., 2013). Proteoglycan degradation has been proposed as a therapeutic strategy to promote neuronal reorganization and recovery following trauma but also might contribute to the development of epilepsy (Kwok et al., 2008). Future studies will be needed to determine if disruption of the PNN contributes to epileptogenesis, memory problems and the changes in the electrophysiology of the FS-PV interneurons that contributes to seizure activity (Zhang and Buckmaster, 2009, Shiri et al., 2015, Toyoda et al., 2015).
Matrix metalloproteinases (MMPs), cleave extracellular proteins including aggrecan, are found throughout the CNS and are necessary for long-term potentiation and regulation of post-synaptic density morphology (Dzwonek et al., 2004). Recently, an increase in the MMP neo-epitopes of aggrecan following status epilepticus (SE) was demonstrated (Rankin-Gee et al., 2015). Only a few of the more than 24 MMPs have been studied in epilepsy, though not all are expressed in the brain. MMP9 and MMP13 are two MMPs found to increase following brain injury, although there are no prior studies exploring their role in degrading PNNs or aggrecan proteolysis in the brain (Nagel et al., 2005). In seizures, MMP9 mRNA and protein levels increase, accompanied by an increase in enzymatic activity (Konopacki et al., 2007, Mizoguchi et al., 2011, Hoehna et al., 2012). Furthermore, pentylenetetrazole (PTZ) kindling is inhibited in MMP9 knockout mice and kindling is increased in MMP9 overexpressing transgenic mice (Wilczynski et al., 2008). Following focal cerebral ischemia, there is up regulation and co-localization of MMP13 with aggrecan, suggesting PNN degradation may occur in response to a variety of brain injuries (Nagel et al., 2005). Another protease family known to cleave aggrecan but less studied in the CNS is ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) proteases known as aggrecanases (Stanton et al., 2011, Gottschall and Howell, 2015). ADAMTS1, 4, 5 and 9, are expressed in the brain and are also candidates for aggrecan degradation following SE.
Here we focus on MMP13 and MMP3, and ADAMTS4 and 5 since they are expressed in the brain and known to specifically cleave aggrecan in cartilage (Fosang et al., 1991, Flannery et al., 1992, Fosang et al., 1996, Dzwonek et al., 2004, Cross et al., 2006, Held-Feindt et al., 2006). The role of the PNN in epileptogenesis or its ability to alter FS-PV cell function is unknown. Identification of proteases involved in degradation of the PNN and extracellular matrix after a brain insult will allow for targeted therapies for prevention of epilepsy in high-risk patients.
Section snippets
Animals
The Institutional Animal Care and Use Committees at the Children's Hospital of Philadelphia and Stanford University approved all the procedures. Male Sprague–Dawley (SD) rats approximately 250 gm in weight, from Charles River (Wilmington, MA, U.S.A.), were randomly assigned into either the control group or the status epilepticus (SE) group. Rats were single- housed in temperature and humidity controlled housing with a 12 h light- 12 h dark cycle and had ad libitum access to food and water.
Seizure induction
Status
Matrix metalloproteinase activity increases in the hippocampus of animals following SE
In a recent study, Rankin-Gee et al. (2015), demonstrated that a MMP cleavage product of aggrecan increases after SE. The MMP cleavage product was concentrated around parvalbumin-positive interneurons. To quantify MMP protease activity after SE we performed a fluorescent protease assay to measure total MMP protease activity in the hippocampal lysates of the SE-induced and control rats. As shown in Fig. 1, there was an increase in the total MMP activity in the hippocampus of SE-induced animals
Discussion
Here we show that there is an increase in global MMP activity and more specifically in MMP13 activity of the hippocampus following status epilepticus. The increase in MMP13 activity is not sufficient to explain the global increase in MMP activity as the time courses differ, total MMP activity increased at both 48 h and 1 week after SE but MMP13 activity only increased at 1 week after SE. MMP3 is a candidate for increased MMP activity following SE as there was a ∼ 5 fold increase in MMP3 mRNA but
Conflict of interest
None
Funding
This work was supported by NIHR01NS056222 grant to BEP and NIH diversity supplement to NIH R01NS056222 and <CURE postdoctoral Taking Flight Award to PAM.
Author contributions
PAM, EKR, DD, LW and EB performed experiments. BEP, DD, PAM and EKR analyzed and interpreted the data. DD, PAM and BEP prepared the manuscript.
References (44)
- et al.
ADAMTS-8 exhibits aggrecanase activity and is expressed in human articular cartilage
Matrix Biol.
(2004) - et al.
Differential expression of ADAMTS-1, −4, −5 and TIMP-3 in rat spinal cord at different stages of acute experimental autoimmune encephalomyelitis
J. Autoimmun.
(2006) - et al.
ADAMTS1, ADAMTS5, ADAMTS9 and aggrecanase-generated proteoglycan fragments are induced following spinal cord injury in mouse
Neurosci. Lett.
(2013) - et al.
CRTC1 nuclear localization in the hippocampus of the pilocarpine-induced status epilepticus model of temporal lobe epilepsy
Neuroscience
(2016) - et al.
Matrix metalloproteinases and their endogenous inhibitors in neuronal physiology of the adult brain
FEBS Lett.
(2004) - et al.
Identification of a stromelysin cleavage site within the interglobular domain of human aggrecan. Evidence for proteolysis at this site in vivo in human articular cartilage
J. Biol. Chem.
(1992) - et al.
Cleavage of cartilage proteoglycan between G1 and G2 domains by stromelysins
J. Biol. Chem.
(1991) - et al.
Degradation of cartilage aggrecan by collagenase-3 (MMP-13)
FEBS Lett.
(1996) - et al.
Deconstructing the perineuronal net: cellular contributions and molecular composition of the neuronal extracellular matrix
Neuroscience
(2012) - et al.
ADAMTS expression and function in central nervous system injury and disorders
Matrix Biol.
(2015)
Matrix metalloproteinase 9 regulates cell death following pilocarpine-induced seizures in the developing brain
Neurobiol. Dis.
Disturbance of perineuronal nets in the perilesional area after photothrombosis is not associated with neuronal death
Exp. Neurol.
Synaptic localization of seizure-induced matrix metalloproteinase-9 mRNA
Neuroscience
Developmental pattern of perineuronal nets in the human prefrontal cortex and their deficit in schizophrenia
Biol. Psychiatry
The perineuronal net component of the extracellular matrix in plasticity and epilepsy
Neurochem. Int.
Aggrecan expression, a component of the inhibitory interneuron perineuronal net, is altered following an early-life seizure
Neurobiol. Dis.
Focal cerebral ischemia induces changes in both MMP-13 and aggrecan around individual neurons
Brain Res.
Doxycycline protects against pilocarpine-induced convulsions in rats, through its antioxidant effect and modulation of brain amino acids
Pharmacol. Biochem. Behav.
Metalloproteinase inhibition prevents inhibitory synapse reorganization and seizure genesis
Neurobiol. Dis.
Modification of seizure activity by electrical stimulation. II. Motor seizure
Electroencephalogr. Clin. Neurophysiol.
Proteoglycan degradation by the ADAMTS family of proteinases
Biochim. Biophys. Acta
Association between protease-specific proteolytic cleavage of brevican and synaptic loss in the dentate gyrus of kainate-treated rats
Neuroscience
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2022, Trends in NeurosciencesCitation Excerpt :Fear conditioning, a model of aversive associative learning, increases MMP9 and MMP2 activity in rodents. Moreover, seizure induction by administration of kainate [31] and pilocarpine [32,33] increases MMP activity in rodents. Psychostimulants such as methamphetamine [34] or cocaine [35] are also known to increase protease activity.
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2020, Brain Research BulletinCitation Excerpt :In pilocarpine-induced epilepsy rat model, it has been reported that aggrecan Cat-315 positive molecules increase in the hippocampus from 2 to 7 days after status epilepticus (Rankin-Gee et al., 2015). Furthermore, studies using rats have shown that enzymes that degrade PNN are elevated in the hippocampus (Dubey et al., 2017; Pollock et al., 2014; Kim et al., 2017). There are various methods, animal species, and stimulation pathways for creating experimental models of epilepsy (Löscher and Ebert, 1996a,b; Kim et al., 2016).
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Co-first Authors.