Figure - available from: Mediators of Inflammation
This content is subject to copyright. Terms and conditions apply.
Representative photomicrographs showing cathepsin S (CatS) immunohistochemistry of tissue from the sham and traumatic brain injury (TBI) groups. In the sham group, almost none of the cells presented a positive morphology, whereas, in the TBI group, many cells were positive for CatS. CatS was present mainly in the cytoplasm. The CatS-positive cells in the TBI group (indicated by arrows) showed two populations of cells with different morphologies.
Source publication
Cathepsin S (CatS) is a cysteine protease normally present in lysosomes. It has long been regarded as an enzyme that is primarily involved in general protein degradation. More recently, mounting evidence has shown that it is involved in Alzheimer disease, seizures, age-related inflammatory processes, and neuropathic pain. In this study, we investig...
Citations
... In this paper, the authors discussed the concept that it is not essential to have a calpain-specific or a cathepsin-specific inhibitor to achieve clinical success in TBI or other neurodegenerative conditions, as both cathepsin and calpain are involved. While cathepsin S has been shown to be involved in the pathological consequences of TBI,43 we did not determine the effects of NA-184 on this cathepsin. Importantly, the protection against mild or severe TBI provided by systemic administration of NA-112 or NA-184 is similar to that provided by deletion of calpain-2 in excitatory neurons of the forebrain.22,40 ...
Our laboratory has shown that calpain‐2 activation in the brain following acute injury is directly related to neuronal damage and the long‐term functional consequences of the injury, while calpain‐1 activation is generally neuroprotective and calpain‐1 deletion exacerbates neuronal injury. We have also shown that a relatively selective calpain‐2 inhibitor, referred to as C2I, enhanced long‐term potentiation and learning and memory, and provided neuroprotection in the controlled cortical impact (CCI) model of traumatic brain injury (TBI) in mice. Using molecular dynamic simulation and Site Identification by Ligand Competitive Saturation (SILCS) software, we generated about 130 analogs of C2I and tested them in a number of in vitro and in vivo assays. These led to the identification of two interesting compounds, NA‐112 and NA‐184. Further analyses indicated that NA‐184, (S)‐2‐(3‐benzylureido)‐ N ‐((R,S)‐1‐((3‐chloro‐2‐methoxybenzyl)amino)‐1,2‐dioxopentan‐3‐yl)‐4‐methylpentanamide, selectively and dose‐dependent inhibited calpain‐2 activity without evident inhibition of calpain‐1 at the tested concentrations in mouse brain tissues and human cell lines. Like NA‐112, NA‐184 inhibited TBI‐induced calpain‐2 activation and cell death in mice and rats, both male and females. Pharmacokinetic and pharmacodynamic analyses indicated that NA‐184 exhibited properties, including stability in plasma and liver and blood–brain barrier permeability, that make it a good clinical candidate for the treatment of TBI.
... For example, proteases aid in food digestion and nutrient absorption. Their physiological role is further highlighted by their involvement in a variety of pathologies, including irritable bowel disease, neuropathic pain, arthritis, myocarditis, systemic muscle pain, and the healing process after surgery [290][291][292][293]. The proteases work by producing or processing molecules through proteolytic cleavage. ...
The largest family of membrane receptors, known as G protein-coupled receptors (GPCRs), are essential to cellular signaling and regulate physiological processes. Presently, ~35%–40% of US FDA-approved medications target GPCRs. A subfamily of GPCRs, Mas-related G protein-coupled receptors (MRGPRs), which belong to the δ-group of the rhodopsin-like GPCRs, was discovered two decades ago. MRGPRs are expressed by small non-myelinated sensory neurons of the dorsal root ganglia and trigeminal ganglia, mast cells, neutrophils, and macrophages and are known to play a role in itch, pain, and pseudo-allergic drug reactions. Moreover, MRGPRs have been identified as mediators in the renin-angiotensin system and cardiovascular biology. In addition, literature suggests that MRGPRs are also involved in inflammatory processes. Despite the fact that humans express eight MRGPRs (MRGPRD to G and X1-X4), information about their activation, signaling pathways, and role in inflammation is insufficient, and most of them are still classified as orphans. Since MRGPRs are involved in itch, pain, and inflammation, which are important physiological processes, the goal of this PhD was to: i) examine the role of MRGPRs in inflammation biology; ii) decipher the activation mechanism of MRGPRs; and iii) elucidate the oligomeric interaction of MRGPRs. Firstly, it was investigated whether β-alanine or alamandine-activated MRGPRD induces interleukin-6 (IL-6) release. It was observed that β-alanine activated MRGPRD-induced IL-6 release via the Gαq/Phospholipase C/NF-kB signaling pathway. Moreover, using IL-6 as a marker for MRGPRD activation, the mechanosensitivity of the MRGPRD and the effect of sterol derivatives, i.e., cholesterol and bile acids, on the activation of MRGPRD were established. Furthermore, it was discovered that the MRGPRD was constitutive (ligand-independent) active. In addition, it was discovered that methyl-β-cyclodextrin, which is known to remove sterols from the plasma membrane, triggered the MRGPRD-mediated IL-6 release. Secondly, in an effort to deorphanize MRGPRs, it was established that cysteine protease cathepsin S activates MRGPRD and MRGPRF. Lastly, using biophysical and biochemical techniques such as luciferase complementation, bioluminescence resonance energy transfer, and co-immunoprecipitation assays, the heteromeric interactions between MRGPRE and MRGPRF were unambiguously detected. Overall, in this doctoral thesis, the primary objective was to improve understanding of the involvement of MRGPRs in inflammatory biology, the activation mechanisms of MRGPRs, and the oligomeric interaction of MRGPRs.
... One point is given for failing to perform each task, thus 0 = minimum deficit and 10 = maximum deficit (Table 1). 20,21 The motor performance of mice was also evaluated at 1 day, 3 days, and 7 days after TBI using the grip test score 18 and neurological score. 22 Both tests were carried out by an investigator who was blinded to the experimental groups. ...
... The brain water content was conducted according to a previous study. 21 Briefly, mouse brain was taken out and placed onto a cooled brain matrix 1 day following TBI. The cerebellum and stem were taken away, and the ipsilateral tissue was weighed to get the wet weight (ww). ...
Aims
Recently, human umbilical cord mesenchymal stem cell (HucMSC)‐derived exosome is a new focus of research in neurological diseases. The present study was aimed to investigate the protective effects of HucMSC‐derived exosome in both in vivo and in vitro TBI models.
Methods
We established both mouse and neuron TBI models in our study. After treatment with HucMSC‐derived exosome, the neuroprotection of exosome was investigated by the neurologic severity score (NSS), grip test score, neurological score, brain water content, and cortical lesion volume. Moreover, we determined the biochemical and morphological changes associated with apoptosis, pyroptosis, and ferroptosis after TBI.
Results
We revealed that treatment of exosome could improve neurological function, decrease cerebral edema, and attenuate brain lesion after TBI. Furthermore, administration of exosome suppressed TBI‐induced cell death, apoptosis, pyroptosis, and ferroptosis. In addition, exosome‐activated phosphatase and tensin homolog‐induced putative kinase protein 1/Parkinson protein 2 E3 ubiquitin–protein ligase (PINK1/Parkin) pathway‐mediated mitophagy after TBI. However, the neuroprotection of exosome was attenuated when mitophagy was inhibited, and PINK1 was knockdown. Importantly, exosome treatment also decreased neuron cell death, suppressed apoptosis, pyroptosis, and ferroptosis and activated the PINK1/Parkin pathway‐mediated mitophagy after TBI in vitro.
Conclusion
Our results provided the first evidence that exosome treatment played a key role in neuroprotection after TBI through the PINK1/Parkin pathway‐mediated mitophagy.
... Ctss is a cysteine protease expressed by diverse immune cells that is responsible for cleaving certain extracellular matrix proteins and cell adhesion molecules to pro-mote immune cell motility [66,67]. In the acute phase after TBI, the upregulation of Ctss expression was mainly observed in microglia; inhibiting Ctss could reduce the level of inflammatory factors, alleviate brain edema, and improve neurobehavioral function [68]. The Cd74 molecule is the cognate receptor of macrophage migration inhibitory factor that is recognized to be a pleiotropic inflammatory cytokine [69,70]. ...
Background:
Traumatic brain injury (TBI) is a common brain injury with a high morbidity and mortality. The complex injury cascade triggered by TBI can result in permanent neurological dysfunction such as cognitive impairment. In order to provide new insights for elucidating the underlying molecular mechanisms of TBI, this study systematically analyzed the transcriptome data of the rat hippocampus in the subacute phase of TBI.
Methods:
Two datasets (GSE111452 and GSE173975) were downloaded from the Gene Expression Omnibus (GEO) database. Systematic bioinformatics analyses were performed, including differentially expressed genes (DEGs) analysis, gene set enrichment analysis (GSEA), Gene Ontology (GO) enrichment analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, protein-protein interaction (PPI) network construction, and hub gene identification. In addition, hematoxylin and eosin (HE), Nissl, and immunohistochemical staining were performed to assess the injured hippocampus in a TBI rat model. The hub genes identified by bioinformatics analyses were verified at the mRNA expression level.
Results:
A total of 56 DEGs were shared in the two datasets. GSEA results suggested significant enrichment in the MAPK and PI3K/Akt pathways, focal adhesion, and cellular senescence. GO and KEGG analyses showed that the common DEGs were predominantly related to immune and inflammatory processes, including antigen processing and presentation, leukocyte-mediated immunity, adaptive immune response, lymphocyte-mediated immunity, phagosome, lysosome, and complement and coagulation cascades. A PPI network of the common DEGs was constructed, and 15 hub genes were identified. In the shared DEGs, we identified two transcription co-factors and 15 immune-related genes. The results of GO analysis indicated that these immune-related DEGs were mainly enriched in biological processes associated with the activation of multiple cells such as microglia, astrocytes, and macrophages. HE and Nissl staining results demonstrated overt hippocampal neuronal damage. Immunohistochemical staining revealed a marked increase in the number of Iba1-positive cells in the injured hippocampus. The mRNA expression levels of the hub genes were consistent with the transcriptome data.
Conclusions:
This study highlighted the potential pathological processes in TBI-related hippocampal impairment. The crucial genes identified in this study may serve as novel biomarkers and therapeutic targets, accelerating the pace of developing effective treatments for TBI-related hippocampal impairment.
... HMOX1 is upregulated in epileptic rats Prakash et al., 2019), and previous studies have found that tissue-type transglutaminase (TGM2) is mostly produced by neurons in the mammalian nervous system and is elevated in neurodegenerative diseases as well as in response to acute CNS injury, which possibly induces neuronal cell death (Tucholski et al., 2006). Cathepsin S (CTSS) is mainly produced by microglia in the hippocampi of kainate-injected mice (Akahoshi et al., 2007), and prohibition of its function resulted in reducing inflammation and alleviating brain edema in a mouse model of traumatic brain injury (Xu et al., 2013). Proliferation cell nuclear antigen (PCNA) is highly expressed in epileptic animal models and in the human brain (Zhang et al., 2005;Liu et al., 2008). ...
Seizures in rodent models that are induced by lithium-pilocarpine mimic human seizures in a highly isomorphic manner. The hippocampus is a brain region that generates and spreads seizures. In order to understand the early phases of seizure events occurring in the hippocampus, global protein expression levels in the hippocampus on day 1 and day 3 were analyzed in lithium-pilocarpine induced acute epileptic rat models using a tandem mass tag-based proteomic approach. Our results showed that differentially expressed proteins were likely to be enhanced rather than prohibited in modulating seizure activity on days 1 and 3 in lithium-pilocarpine induced seizure rats. The differentially regulated proteins differed on days 1 and 3 in the seizure rats, indicating that different molecules and pathways are involved in seizure events occurring from day 1 to day 3 following lithium-pilocarpine administration. In regard to subcellular distribution, the results suggest that post-seizure cellular function in the hippocampus is possibly regulated in a differential manner on seizure progression. Gene ontology annotation results showed that, on day 1 following lithium-pilocarpine administration, it is likely necessary to regulate macromolecular complex assembly, and cell death, while on day 3, it may be necessary to modulate protein metabolic process, cytoplasm, and protein binding. Protein metabolic process rather than macromolecular complex assembly and cell death were affected on day 3 following lithium-pilocarpine administration. The extracellular matrix, receptors, and the constitution of plasma membranes were altered most strongly in the development of seizure events. In a KEGG pathway enrichment cluster analysis, the signaling pathways identified were relevant to sustained angiogenesis and evading apoptosis, and complement and coagulation cascades. On day 3, pathways relevant to Huntington’s disease, and tumor necrosis factor signaling were most prevalent. These results suggest that seizure events occurring in day 1 modulate macromolecular complex assembly and cell death, and in day 3 modulate biological protein metabolic process. In summary, our study found limited evidence for ongoing seizure events in the hippocampus of lithium-pilocarpine induced animal models; nevertheless, evaluating the global differential expression of proteins and their impacts on bio-function may offer new perspectives for studying epileptogenesis in the future.
... Cathepsins are widely involved in various cellular activities in cells, such as the synthesis and activation of hormones, the process of apoptosis and autophagy, etc. Several studies have found that cathepsins B and L are involved in the pathophysiological process of various neurological diseases, such as ischemic stroke, Alzheimer's disease, Parkinson's disease, and traumatic brain injury (Lipton, 1999;Xu et al., 2013;Yamashima, 2013). ...
Ischemic stroke is a serious cerebrovascular event that results in cell death, blood-brain barrier dysfunction, tissue degradation, and inflammation, often leading to permanent disability or death. As the incidence of ischemic stroke continues to rise globally, it is crucial to examine the mechanisms of the various proteins and molecules contributing to worsened patient outcome and recovery. Cathepsin L, a cysteine protease known for degrading tissues in lysosomes and elsewhere, may play a role in brain tissue loss and inflammation after stroke. Studies have suggested that cathepsin L appears in the ischemic core shortly after stroke is induced. Using immunohistochemical staining, mass spectrometry, and other assays, the increase of cathepsin L in the brain was correlated with extracellular matrix and perlecan degradation after ischemic stroke. Additionally, injection of a cathepsin L inhibitor significantly reduced brain infarct size and improved functional scores. More research is needed to elucidate cathepsin L's role in post-stroke inflammation and brain damage, in order to further explore the factors contributing to worsened patient outcome after ischemic stroke and work toward finding better therapeutic interventions.
... siRNA-CatX significantly reduced NO production in co-stimulated cells compared to siRNA-Ctrl (Supplementary Figure S5B). Additionally, to exclude the involvement of other cysteine cathepsins, such as cathepsins B, L, and S, cells were pre-incubated with specific inhibitors against cathepsin B (CA-074; [53]), cathepsin L (CLIK-148; [54]), and cathepsin S (LHVS; [55]). Significant anti-inflammatory effects against LPS/poly(I:C)induced microglia activation were observed for the cathepsin X inhibitor AMS36 (24 h). ...
Microglia are resident macrophages in the central nervous system that are involved in immune responses driven by Toll-like receptors (TLRs). Microglia-mediated inflammation can lead to central nervous system disorders, and more than one TLR might be involved in these pathological processes. The cysteine peptidase cathepsin X has been recognized as a pathogenic factor for inflammation-induced neurodegeneration. Here, we hypothesized that simultaneous TLR3 and TLR4 activation induces synergized microglia responses and that these phenotype changes affect cathepsin X expression and activity. Murine microglia BV2 cells and primary murine microglia were exposed to the TLR3 ligand polyinosinic-polycytidylic acid (poly(I:C)) and the TLR4 ligand lipopolysaccharide (LPS), individually and simultaneously. TLR3 and TLR4 co-activation resulted in increased inflammatory responses compared to individual TLR activation, where poly(I:C) and LPS induced distinct patterns of proinflammatory factors together with different patterns of cathepsin X expression and activity. TLR co-activation decreased intracellular cathepsin X activity and increased cathepsin X localization at the plasma membrane with concomitant increased extracellular cathepsin X protein levels and activity. Inhibition of cathepsin X in BV2 cells by AMS36, cathepsin X inhibitor, significantly reduced the poly(I:C)- and LPS-induced production of proinflammatory cytokines as well as apoptosis. Additionally, inhibiting the TLR3 and TLR4 common signaling pathway, PI3K, with LY294002 reduced the inflammatory responses of the poly(I:C)- and LPS-activated microglia and recovered cathepsin X activity. We here provide evidence that microglial cathepsin X strengthens microglia activation and leads to subsequent inflammation-induced neurodegeneration. As such, cathepsin X represents a therapeutic target for treating neurodegenerative diseases related to excess inflammation.
... Brain water content was quantified as previously described (8). It was measured by the wet-dry weight ration method (18,21). Animals were anesthetized with sodium pentobarbital (50 mg/kg; IP) and the brains were quickly dissected at 24 hr following TBI. ...
Objectives:
Traumatic brain injury (TBI) is a prominent health problem worldwide and it may lead to cognitive dysfunction, disability, and even death. To date, there is no effective treatment for TBI. Our previous study showed that Huperzine A (HupA) improved cognitive function in a mouse model of TBI. However, the detailed mechanism of HupA remains unaddressed. In this study, we investigated the possible mechanism of the neuroprotective effect of HupA.
Materials and methods:
C57BL/6 mice were randomly divided into 3 groups as sham, injured with vehicle treatment, and injured with HupA treatment groups. The Morris water maze task was used to evaluate the impairment of special learning and memory. Brain edema was as-sessed by measuring the wet weight to dry weight ratio. Malondialdehyde (MDA) and glutathione peroxidase (GPx) levels were measured for oxidative stress. Protein expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygen-ase-1(HO-1), and synaptophysin were detected by Western blot. The brain sections were stained with hematoxylin-eosin (H&E) for histology study.
Results:
We found that HupA therapy improved histology and cognitive functional outcomes after TBI. HupA reduced brain edema in TBI mice. furthermore, HupA inhibited ox-idative stress. HupA promoted nuclear factor erythroid 2-related factor 2 (Nrf2) nu-clear translocation and activated Nrf2 after TBI.
Conclusion:
HupA protects against TBI through antioxidative effects via the Nrf2-ARE pathway.
... Brain water content was measured by a wet/dry ration method (Xu et al., 2013). In brief, the brain of a rat was quickly obtained 24 h after SAH, and temporal cortical tissues were weighed immediately to acquire wet weight (WW). ...
Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) has been shown to play a pivotal role in the regulation of mitochondrial biogenesis in diseases. Resveratrol (RSV), a natural polyphenolic reagent, has powerful antioxidant properties and the ability to scavenge mitochondrial reactive oxygen species (ROS) in a variety of central nervous system diseases. However, the underlying molecular mechanisms of RSV on mitochondrial biogenesis in early brain injury (EBI) following subarachnoid hemorrhage (SAH) remain poorly understood. This study aimed to explore the potential neuroprotective effects of RSV on mitochondrial biogenesis and function by activation of the PGC-1α signaling pathway in a prechiasmatic cistern SAH model. PGC-1α expression and related mitochondrial biogenesis were detected. Amounts of nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM) were determined to evaluate the extent of mitochondrial biogenesis. Increased PGC-1α and mitochondrial biogenesis after SAH were observed in the temporal cortex. Resveratrol increased the expression of PGC-1α, NRF1, and TFAM, and promoted PGC-1α nuclear translocation. Moreover, RSV could scavenge excess ROS, increase the activity of superoxide dismutase (SOD), enhance the potential of mitochondrial membrane and ATP levels, reduce the number of mitochondrial DNA copy, and decrease the level of malondialdehyde (MDA). RSV significantly ameliorated the release of apoptosis-related cytokines, namely P53, cleaved caspase-3, cytochrome c, and BAX, leading to the amelioration of neuronal apoptosis, brain edema, and neurological impairment 24 h after SAH. These results indicate that resveratrol promotes mitochondrial biogenesis and function by activation of the PGC-1α signaling pathway in EBI following SAH.
... The D3R Grand Challenge 4 was organized in 2018 and was based on two protein targets: cathepsin S (CatS, Fig. 1b), which was already present in the previous D3R Grand Challenge 3, and beta-secretase 1 (BACE, Fig. 1a). Cathepsin S is a lysosomal cysteine protease involved, inter alia, in antigen presentation, nociception, itch, pain and whose regulation may be important in several diseases as psoriasis, rheumatoid arthritis and glioblastoma [1][2][3][4][5][6][7][8][9]. Beta-secretase 1 is an aspartic acid protease involved in the formation of myelin 1 3 sheaths in peripheral nerve cells and in Alzheimer's disease by cleavage of the amyloid precursor protein, leading, in the end, to amyloid-peptide aggregation [10][11][12][13]. ...
Using the D3R Grand Challenge 4 dataset containing Beta-secretase 1 (BACE) and Cathepsin S (CatS) inhibitors, we have evaluated the performance of our in-house docking workflow that involves in the first step the selection of the most suitable docking software for the system of interest based on structural and functional information available in public databases, followed by the docking of the dataset to predict the binding modes and ranking of ligands. The macrocyclic nature of the BACE ligands brought additional challenges, which were dealt with by a careful preparation of the three-dimensional input structures for ligands. This provided top-performing predictions for BACE, in contrast with CatS, where the predictions in the absence of guiding constraints provided poor results. These results highlight the importance of previous structural knowledge that is needed for correct predictions on some challenging targets. After the end of the challenge, we also carried out free energy calculations (i.e. in a non-blinded manner) for CatS using the pmx software and several force fields (AMBER, Charmm). Using knowledge-based starting pose construction allowed reaching remarkable accuracy for the CatS free energy estimates. Interestingly, we show that the use of a consensus result, by averaging the results from different force fields, increases the prediction accuracy.
