MMPs in learning and memory and neuropsychiatric disorders

Input specificity of NMDA-dependent GABAergic plasticity in the hippocampus

Sensory experiences and learning induce long-lasting changes in both excitatory and inhibitory synapses, thereby providing a crucial substrate for memory. However, the co-tuning of excitatory long-term potentiation (eLTP) or depression (eLTD) with the simultaneous changes at inhibitory synapses (iLTP/iLTD) remains unclear. Herein, we investigated the co-expression of NMDA-induced synaptic plasticity at excitatory and inhibitory synapses in hippocampal CA1 pyramidal cells (PCs) using a combination of electrophysiological, optogenetic, and pharmacological approaches. We found that inhibitory inputs from somatostatin (SST) and parvalbumin (PV)-positive interneurons onto CA1 PCs display input-specific long-term plastic changes following transient NMDA receptor activation. Notably, synapses from SST-positive interneurons consistently exhibited iLTP, irrespective of the direction of excitatory plasticity, whereas synapses from PV-positive interneurons predominantly showed iLTP concurrent with eLTP, rather than eLTD. As neuroplasticity is known to depend on the extracellular matrix, we tested the impact of metalloproteinases (MMP) inhibition. MMP3 blockade interfered with GABAergic plasticity for all inhibitory inputs, whereas MMP9 inhibition selectively blocked eLTP and iLTP in SST-CA1PC synapses co-occurring with eLTP but not eLTD. These findings demonstrate the dissociation of excitatory and inhibitory plasticity co-expression. We propose that these mechanisms of plasticity co-expression may be involved in maintaining excitation-inhibition balance and modulating neuronal integration modes.

From molecules to behavior: Implications for perineuronal net remodeling in learning and memory

Perineuronal nets (PNNs) are condensed extracellular matrix (ECM) structures found throughout the central nervous system that regulate plasticity. They consist of a heterogeneous mix of ECM components that form lattice-like structures enwrapping the cell body and proximal dendrites of particular neurons. During development, accumulating research has shown that the closure of various critical periods of plasticity is strongly linked to experience-driven PNN formation and maturation. PNNs provide an interface for synaptic contacts within the holes of the structure, generally promoting synaptic stabilization and restricting the formation of new synaptic connections in the adult brain. In this way, they impact both synaptic structure and function, ultimately influencing higher cognitive processes. PNNs are highly plastic structures, changing their composition and distribution throughout life and in response to various experiences and memory disorders, thus serving as a substrate for experience- and disease-dependent cognitive function. In this review, we delve into the proposed mechanisms by which PNNs shape plasticity and memory function, highlighting the potential impact of their structural components, overall architecture, and dynamic remodeling on functional outcomes in health and disease.

Matrix metalloproteinase-9: A magic drug target in neuropsychiatry?

Neuropsychiatric conditions represent a major medical and societal challenge. The etiology of these conditions is very complex and combines genetic and environmental factors. The latter, for example, excessive maternal or early postnatal inflammation, as well as various forms of psychotrauma, often act as triggers leading to mental illness after a prolonged latent period (sometimes years). Matrix metalloproteinase-9 (MMP-9) is an extracellularly and extrasynaptic operating protease that is markedly activated in response to the aforementioned environmental insults. MMP-9 has also been shown to play a pivotal role in the plasticity of excitatory synapses, which, in its aberrant form, has repeatedly been implicated in the etiology of mental illness. In this conceptual review, we evaluate the experimental and clinical evidence supporting the claim that MMP-9 is uniquely positioned to be considered a drug target for ameliorating the adverse effects of environmental insults on the development of a variety of neuropsychiatric conditions, such as schizophrenia, bipolar disorder, major depression, autism spectrum disorders, addiction, and epilepsy. We also identify specific challenges and bottlenecks hampering the translation of knowledge on MMP-9 into new clinical treatments for the conditions above and suggest ways to overcome these barriers.

Elevated plasma matrix metalloproteinase 9 in schizophrenia patients associated with poor antipsychotic treatment response and white matter density deficits

Oxidative stress and neuroinflammation contribute to schizophrenia (SCZ) pathology and may influence treatment efficacy. Matrix metalloproteinase 9 (MMP9) is a critical molecular node mediating the interaction between oxidative stress and inflammation, and so may influence treatment efficacy. Here we examined the associations of plasma MMP9 concentration with antipsychotic drug responses, clinical symptoms, and brain structure. A total of 129 healthy controls and 124 patients with SCZ were included in this study. Patients were monitored clinically during 8 weeks of antipsychotic treatment and classified as poor responders (n = 49) or good responders (n = 75). We then compared plasma MMP9 concentrations in healthy controls at baseline and both SCZ responder groups at baseline and after the 8-week antipsychotic treatment regimen. Cognitive function was also examined using the MATRICS Consensus Cognitive Battery. In addition, we extracted regional white matter density from magnetic resonance images of patients. Compared to healthy controls, plasma MMP9 levels were significantly elevated in poor responders at baseline and negatively correlated with both white matter density in the right superior temporal gyrus and the change in cognitive symptoms after treatment. Conversely, there was no significant difference in plasma MMP9 between good responders and healthy controls, and no associations of plasma MMP9 with cognitive symptoms or regional white matter density among good responders. Elevated plasma MMP9 is associated with poor antipsychotic drug efficacy and white matter deficits in SCZ patients, and so may be a useful biomarker to guide personalized treatment.

Bioinformatic Evaluation of KLF13 Genetic Variant: Implications for Neurodevelopmental and Psychiatric Symptoms

The Krüppel-like factor (KLF) family represents a group of transcription factors (TFs) performing different biological processes that are crucial for proper neuronal function, including neuronal development, synaptic plasticity, and neuronal survival. As reported, genetic variants within the KLF family have been associated with a wide spectrum of neurodevelopmental and psychiatric symptoms. In a patient exhibiting attention deficit hyperactivity disorder (ADHD) combined with both neurodevelopmental and psychiatric symptoms, whole-exome sequencing (WES) analysis revealed a de novo heterozygous variant within the Krüppel-like factor 13 (KLF13) gene, which belongs to the KLF family and regulates axonal growth, development, and regeneration in mice. Moreover, in silico analyses pertaining to the likely pathogenic significance of the variant and the impact of the mutation on the KLF13 protein structure suggested a potential deleterious effect. In fact, the variant was localized in correspondence to the starting residue of the N-terminal domain of KLF13, essential for protein-protein interactions, DNA binding, and transcriptional activation or repression. This study aims to highlight the potential involvement of the KLF13 gene in neurodevelopmental and psychiatric disorders. Nevertheless, we cannot rule out that excluded variants, those undetectable by WES, or the polygenic risk may have contributed to the patient's phenotype given ADHD's high polygenic risk. However, further functional studies are required to validate its potential contribution to these disorders.

Preferential and sustained platelet activation in COVID-19 survivors with mental disorders

Pre-existing mental disorders are considered a risk factor for severe COVID-19 outcomes, possibly because of higher vascular burden. Moreover, an unconventional platelet activation characterizes COVID-19 and contributes to inflammatory and thrombotic manifestations. In the light of the inflammation theory of mental disorders, we hypothesized that patients with mental disorders could be sensitive to the SARS-CoV-2 elicited platelet activation. We investigated platelet activation in 141 COVID-19 survivors at one month after clearance of the virus, comparing subjects with or without an established pre-existing diagnosis of mental disorder according to the DSM-5. We found that platelets from patients with a positive history of psychiatric disorder underwent unconventional activation more frequently than conventional activation or no activation at all. Such preferential activation was not detected when platelets from patients without a previous psychiatric diagnosis were studied. When testing the effects of age, sex, and psychiatric history on the platelet activation, GLZM multivariate analysis confirmed the significant effect of diagnosis only. These findings suggest a preferential platelet activation during acute COVID-19 in patients with a pre-existing psychiatric disorder, mediated by mechanisms associated with thromboinflammation. This event could have contributed to the higher risk of severe outcome in the psychiatric population.

Role of inflammatory mediators in intracranial aneurysms: A review

The formation, growth, and rupture of intracranial aneurysms (IAs) involve hemodynamics, blood pressure, external stimuli, and a series of hormonal changes. In addition, inflammatory response causes the release of a series of inflammatory mediators, such as IL, TNF-α, MCP-1, and MMPs, which directly or indirectly promote the development process of IA. However, the specific role of these inflammatory mediators in the pathophysiological process of IA remains unclear. Recently, several anti-inflammatory, lipid-lowering, hormone-regulating drugs have been found to have a potentially protective effect on reducing IA formation and rupture in the population. These therapeutic mechanisms have not been fully elucidated, but we can look for potential therapeutic targets that may interfere with the formation and breakdown of IA by studying the relevant inflammatory response and the mechanism of IA formation and rupture involved in inflammatory mediators.

Bipolar disorder staging and the impact it has on its management: an update

INTRODUCTION

The longitudinal course of bipolar disorder (BD) is associated with an active process of neuroprogression, characterized by structural brain alterations and progressive functional impairment. In the last decades, a growing need of a standardized staging model for BD arose, with the aim of a more appropriate definition of stage-specific clinical manifestations and the identification of more customized therapeutic tools.

AREAS COVERED

The authors review the literature on clinical aspects, neurobiological correlates and treatment issues related to BD progression. Thereafter, they address the definition, constructs, and evolution of the staging concept, focusing on the clinical applications of BD staging models available in literature.

EXPERT OPINION

Although several staging models for BD have been proposed to date, their application in clinical practice is still relatively scant. This may have a detrimental impact on the clinical and therapeutic management of BD, in terms of early and proper diagnosis as well as tailored treatment interventions according to the different stages of illness. Future research efforts should tend to the integration of recent insights on neuroimaging and epigenetic markers, toward a standardized and multidimensional staging model.

Yigansan ameliorates maternal immune activation-induced autism-like behaviours by regulating the IL-17A/TRAF6/MMP9 pathway: Network analysis and experimental validation

BACKGROUND

Maternal immune activation (MIA) is a significant factor inducing to autism spectrum disorder (ASD) in offspring. The fundamental principle underlying MIA is that inflammation during pregnancy impedes fetal brain development and triggers behavioural alterations in offspring. The intricate pathogenesis of ASD renders drug treatment effects unsatisfactory. Traditional Chinese medicine has strong potential due to its multiple therapeutic targets. Yigansan, composed of seven herbs, is one of the few that has been proven to be effective in treating neuro-psychiatric disorders among numerous traditional Chinese medicine compounds, but its therapeutic effect on ASD remains unknown.

HYPOTHESIS

Yigansan improves MIA-induced ASD-like behaviours in offspring by regulating the IL-17 signalling pathway.

METHODS

Pregnant C57BL/6J mice were intraperitoneally injected with poly(I:C) to construct MIA models and offspring ASD models. Network analysis identified that the IL-17A/TRAF6/MMP9 pathway is a crucial pathway, and molecular docking confirmed the binding affinity between the monomer of Yigansan and target proteins. qRT-PCR and Western blot were used to detect the expression levels of inflammatory factors and pathway proteins, immunofluorescence was used to detect the distribution of IL-17A, and behavioural tests were used to evaluate the ASD-like behaviours of offspring.

RESULTS

We demonstrated that Yigansan can effectively alleviate MIA-induced neuroinflammation of adult offspring by regulating the IL-17A/TRAF6/MMP9 pathway, and the expression of IL-17A was reduced in the prefrontal cortex. Importantly, ASD-like behaviours have been significantly improved. Moreover, we identified that quercetin is the effective monomer for Yigansan to exert therapeutic effects.

CONCLUSION

Overall, this study was firstly to corroborate the positive therapeutic effect of Yigansan in the treatment of ASD. We elucidated the relevant molecular mechanism and regulatory pathway involved, determined the optimal therapeutic dose and effective monomer, providing new solutions for the challenges of drug therapy for ASD.

Matrix metalloproteinase 9 (MMP-9) activity, hippocampal extracellular free water, and cognitive deficits are associated with each other in early phase psychosis

Increasing evidence points toward the role of the extracellular matrix, specifically matrix metalloproteinase 9 (MMP-9), in the pathophysiology of psychosis. MMP-9 is a critical regulator of the crosstalk between peripheral and central inflammation, extracellular matrix remodeling, hippocampal development, synaptic pruning, and neuroplasticity. Here, we aim to characterize the relationship between plasma MMP-9 activity, hippocampal microstructure, and cognition in healthy individuals and individuals with early phase psychosis. We collected clinical, blood, and structural and diffusion-weighted magnetic resonance imaging data from 39 individuals with early phase psychosis and 44 age and sex-matched healthy individuals. We measured MMP-9 plasma activity, hippocampal extracellular free water (FW) levels, and hippocampal volumes. We used regression analyses to compare MMP-9 activity, hippocampal FW, and volumes between groups. We then examined associations between MMP-9 activity, FW levels, hippocampal volumes, and cognitive performance assessed with the MATRICS battery. All analyses were controlled for age, sex, body mass index, cigarette smoking, and years of education. Individuals with early phase psychosis demonstrated higher MMP-9 activity (p < 0.0002), higher left (p < 0.05) and right (p < 0.05) hippocampal FW levels, and lower left (p < 0.05) and right (p < 0.05) hippocampal volume than healthy individuals. MMP-9 activity correlated positively with hippocampal FW levels (all participants and individuals with early phase psychosis) and negatively with hippocampal volumes (all participants and healthy individuals). Higher MMP-9 activity and higher hippocampal FW levels were associated with slower processing speed and worse working memory performance in all participants. Our findings show an association between MMP-9 activity and hippocampal microstructural alterations in psychosis and an association between MMP-9 activity and cognitive performance. Further, more extensive longitudinal studies should examine the therapeutic potential of MMP-9 modulators in psychosis.

The impact of doxycycline on human contextual fear memory

RATIONALE

 Previous work identified an attenuating effect of the matrix metalloproteinase (MMP) inhibitor doxycycline on fear memory consolidation. This may present a new mechanistic approach for the prevention of trauma-related disorders. However, so far, this has only been unambiguously demonstrated in a cued delay fear conditioning paradigm, in which a simple geometric cue predicted a temporally overlapping aversive outcome. This form of learning is mainly amygdala dependent. Psychological trauma often involves the encoding of contextual cues, which putatively necessitates partly different neural circuits including the hippocampus. The role of MMP signalling in the underlying neural pathways in humans is unknown.

METHODS

Here, we investigated the effect of doxycycline on configural fear conditioning in a double-blind placebo-controlled randomised trial with 100 (50 females) healthy human participants.

RESULTS

Our results show that participants successfully learned and retained, after 1 week, the context-shock association in both groups. We find no group difference in fear memory retention in either of our pre-registered outcome measures, startle eye-blink responses and pupil dilation. Contrary to expectations, we identified elevated fear-potentiated startle in the doxycycline group early in the recall test, compared to the placebo group.

CONCLUSION

Our results suggest that doxycycline does not substantially attenuate contextual fear memory. This might limit its potential for clinical application.

Epidermal Growth Factor Suppresses the Development of GABAergic Neurons Via the Modulation of Perineuronal Net Formation in the Neocortex of Developing Rodent Brains

Previously, we reported that epidermal growth factor (EGF) suppresses GABAergic neuronal development in the rodent cortex. Parvalbumin-positive GABAergic neurons (PV neurons) have a unique extracellular structure, perineuronal nets (PNNs). PNNs are formed during the development of PV neurons and are mainly formed from chondroitin sulfate (CS) proteoglycans (CSPGs). We examined the effect of EGF on CSPG production and PNN formation as a potential molecular mechanism for the inhibition of inhibiting GABAergic neuronal development by EGF. In EGF-overexpressing transgenic (EGF-Tg) mice, the number of PNN-positive PV neurons was decreased in the cortex compared with that in wild-type mice, as in our previous report. The amount of CS and neurocan was also lower in the cortex of EGF-Tg mice, with a similar decrease observed in EGF-treated cultured cortical neurons. PD153035, an EGF receptor (ErbB1) kinase inhibitor, prevented those mentioned above excess EGF-induced reduction in PNN. We explored the molecular mechanism underlying the effect of EGF on PNNs using fluorescent substrates for matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs). EGF increased the enzyme activity of MMPs and ADAMs in cultured neurons. These enzyme activities were also increased in the EGF-Tg mice cortex. GM6001, a broad inhibitor of MMPs and ADAMs, also blocked EGF-induced PNN reductions. Therefore, EGF/EGF receptor signals may regulate PNN formation in the developing cortex.

Cold atmospheric plasma attenuates skin cancer via ROS induced apoptosis

BACKGROUND

Cold atmospheric plasma (CAP) has been widely used in biomedical research, especially in vitro cancer therapy. Cutaneous squamous cell carcinoma (CSCC) is a malignant tumor originating from epidermal keratinocytes. However, the mechanism of CAP therapy on CSCC remains unclear.

METHODS AND RESULTS

The animal models of CSCC induced by 7,12-dimethylbenz(a) anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA) were constructed. For the CAP treatment group, after each TPA application, CAP was administered for 3 min twice weekly after drying. HE staining were used to detect the pathological status of tumor tissue in each group. The levels of PCNA, Bcl-2, Bax, MMP2 and MMP9 were evaluated by western blot and qPCR. TUNEL staining were used to detect apoptosis in tumor tissues. In vivo, serum samples were used for ELISA of total ROS. MTT assay was used to detect the viability of A431 cells. Western blot and qPCR were used to detect the levels of PCNA, Bcl-2, Bax, MMP2 and MMP9 in A431 cells. A431 cell proliferation was examined by colony formation assay. The proportions of apoptosis of A431 cells were detected by flow cytometry. Transwell assessed the ability of A431 cells migration and proliferation. We found that CAP could induce skin cancer cells apoptosis and inhibit the progress of skin cancer. Through experiments in vitro, reactive oxygen species (ROS) generated by N-acetylcysteine (NAC) and CAP inhibited the proliferation and migration of A431 skin cancer cells while promoting apoptosis.

CONCLUSIONS

These evidences suggest the protective effect of CAP in CSCC, and CAP has the potential clinical application of CSCC.

Depression: Monocytes on my mind

Activation of the peripheral immune system contributes to stress-related neuropsychiatric symptoms. Recently in Nature, Cathomas et al. demonstrate that stress-induced social avoidance is mediated by monocyte-derived MMP8 that remodels the extracellular space of the nucleus accumbens.

Progress in the Treatment of Central Nervous System Diseases Based on Nanosized Traditional Chinese Medicine

Traditional Chinese Medicine (TCM) is widely used in clinical practice to treat diseases related to central nervous system (CNS) damage. However, the blood-brain barrier (BBB) constitutes a significant impediment to the effective delivery of TCM, thus substantially diminishing its efficacy. Advances in nanotechnology and its applications in TCM (also known as nano-TCM) can deliver active ingredients or components of TCM across the BBB to the targeted brain region. This review provides an overview of the physiological and pathological mechanisms of the BBB and systematically classifies the common TCM used to treat CNS diseases and types of nanocarriers that effectively deliver TCM to the brain. Additionally, drug delivery strategies for nano-TCMs that utilize in vivo physiological properties or in vitro devices to bypass or cross the BBB are discussed. This review further focuses on the application of nano-TCMs in the treatment of various CNS diseases. Finally, this article anticipates a design strategy for nano-TCMs with higher delivery efficiency and probes their application potential in treating a wider range of CNS diseases.

Behavioral and transcriptional effects of repeated electroconvulsive seizures in the neonatal MK-801-treated rat model of schizophrenia

RATIONALE

Electroconvulsive therapy (ECT) is an effective treatment modality for schizophrenia. However, its antipsychotic-like mechanism remains unclear.

OBJECTIVES

To gain insight into the antipsychotic-like actions of ECT, this study investigated how repeated treatments of electroconvulsive seizure (ECS), an animal model for ECT, affect the behavioral and transcriptomic profile of a neurodevelopmental animal model of schizophrenia.

METHODS

Two injections of MK-801 or saline were administered to rats on postnatal day 7 (PN7), and either repeated ECS treatments (E10X) or sham shock was conducted daily from PN50 to PN59. Ultimately, the rats were divided into vehicle/sham (V/S), MK-801/sham (M/S), vehicle/ECS (V/E), and MK-801/ECS (M/E) groups. On PN59, prepulse inhibition and locomotor activity were tested. Prefrontal cortex transcriptomes were analyzed with mRNA sequencing and network and pathway analyses, and quantitative real-time polymerase chain reaction (qPCR) analyses were subsequently conducted.

RESULTS

Prepulse inhibition deficit was induced by MK-801 and normalized by E10X. In M/S vs. M/E model, Egr1, Mmp9, and S100a6 were identified as center genes, and interleukin-17 (IL-17), nuclear factor kappa B (NF-κB), and tumor necrosis factor (TNF) signaling pathways were identified as the three most relevant pathways. In the V/E vs. V/S model, mitophagy, NF-κB, and receptor for advanced glycation end products (RAGE) pathways were identified. qPCR analyses demonstrated that Igfbp6, Btf3, Cox6a2, and H2az1 were downregulated in M/S and upregulated in M/E.

CONCLUSIONS

E10X reverses the behavioral changes induced by MK-801 and produces transcriptional changes in inflammatory, insulin, and mitophagy pathways, which provide mechanistic insight into the antipsychotic-like mechanism of ECT.

Epigenetics and suicide: investigating altered H3K14ac unveiled differential expression in ADORA2A, B4GALT2 and MMP14

Background: Environmental factors make an important contribution to suicide. Histone tails are prone to different modifications, leading to changes of chromatin (de)condensation and consequently gene expression. Materials & methods: Level of H3K14ac was studied with chromatin immunoprecipitation followed by high-throughput DNA sequencing. Genes were further validated with RT-qPCR; using hippocampal tissue. Results: We showed lowered H3K14ac levels in individuals who died by suicide. The genes ADORA2A, B4GALT2 and MMP14 showed differential expression in individuals who died by suicide. Identified genetic and protein interactions among genes show interactions with suicide-related genes. Conclusion: Further investigations of histone modifications in association with DNA methylation and miRNA are needed to expand our knowledge of the genes that could significantly contribute to suicide.

System biology approaches to identify hub genes linked with ECM organization and inflammatory signaling pathways in schizophrenia pathogenesis

Schizophrenia (SZ) is a chronic and devastating mental illness that affects around 20 million individuals worldwide. Cognitive deficits and structural and functional changes of the brain, abnormalities of brain ECM components, chronic neuroinflammation, and devastating clinical manifestation during SZ are likely etiological factors shown by affected individuals. However, the pathophysiological events associated with multiple regulatory pathways involved in the brain of this complex disorder are still unclear. This study aimed to develop a pipeline based on bioinformatics and systems biology approaches for identifying potential therapeutic targets involving possible biological mechanisms from SZ patients and healthy volunteers. About 420 overlapping differentially expressed genes (DEGs) from three RNA-seq datasets were identified. Gene ontology (GO), and pathways analysis showed several biological mechanisms enriched by the commonly shared DEGs, including extracellular matrix organization (ECM) organization, collagen fibril organization, integrin signaling pathway, inflammation mediated by chemokines and cytokines signaling pathway, and GABA-B receptor II and IL4 mediated signaling. Besides, 15 hub genes (FN1, COL1A1, COL3A1, COL1A2, COL5A1, COL2A1, COL6A2, COL6A3, MMP2, THBS1, DCN, LUM, HLA-A, HLA-C, and FBN1) were discovered by comprehensive analysis, which was mainly involved in the ECM organization and inflammatory signaling pathway. Furthermore, the miRNA target of the hub genes was analyzed with the random-forest-based approach software miRTarBase. In addition, the transcriptional factors and protein kinases regulating overlapping DEGs in SZ, namely, SUZ12, EZH2, TRIM28, TP53, EGR1, CSNK2A1, GSK3B, CDK1, and MAPK14, were also identified. The results point to a new understanding that the hub genes (fibronectin 1, collagen, matrix metalloproteinase-2, and lumican) in the ECM organization and inflammatory signaling pathways may be involved in the SZ occurrence and pathogenesis.

Effects of minocycline on dendrites, dendritic spines, and microglia in immature mouse brains after kainic acid-induced status epilepticus

PURPOSE

This study aimed to investigate whether minocycline could influence alterations of microglial subtypes, the morphology of dendrites and dendritic spines, the microstructures of synapses and synaptic proteins, or even cognition outcomes in immature male mice following status epilepticus (SE) induced by kainic acid.

METHODS

Golgi staining was performed to visualize the dendrites and dendritic spines of neurons of the hippocampus. The microstructures of synapses and synaptic proteins were observed using transmission electron microscopy and western blotting analysis, respectively. Microglial reactivation and their markers were evaluated using flow cytometry. The Morris water maze (MWM) test was used to analyze spatial learning and memory ability.

RESULTS

Significant partial spines increase (predominate in thin spines) was observed in the dendrites of neurons after acute SE and partial loss (mainly in thin spines) was presented by days 14 and 28 post-SE. The postsynaptic ultrastructure was impaired on the 7th and 14th days after SE. The proportion of M1 microglia increased significantly only after acute SE Similarly, the proportion of M2 microglia increased in the acute stage with high expression levels of all surface markers. In contrast, a decrease in M2 microglia and their markers was noted by day 14 post-SE. Minocycline could reverse the changes in dendrites and synaptic proteins caused by SE, and increase the levels of synaptic proteins. Meanwhile, minocycline could inhibit the reactivation of M1 microglia and the expression of their markers, except for promoting CD200R. In addition, treatment with minocycline could regulate the expression of M2 microglia and their surface markers, as well as ameliorating the impaired spatial learning and memory on the 28th day after SE.

CONCLUSIONS

Dendritic spines and microglia are dynamically changed after SE. Minocycline could ameliorate the impaired cognition in the kainic acid-induced mouse model by decreasing the damage to dendrites and altering microglial reactivation.

Redefining metalloproteases specificity through network proteolysis

Proteolytic processes on cell surfaces and extracellular matrix (ECM) sustain cell behavior and tissue integrity in health and disease. Matrix metalloproteases (MMPs) and a disintegrin and metalloproteases (ADAMs) remodel cell microenvironments through irreversible proteolysis of ECM proteins and cell surface bioactive molecules. Pan-MMP inhibitors in inflammation and cancer clinical trials have encountered challenges due to promiscuous activities of MMPs. Systems biology advances revealed that MMPs initiate multifactorial proteolytic cascades, creating new substrates, activating or suppressing other MMPs, and generating signaling molecules. This review highlights the intricate network that underscores the role of MMPs beyond individual substrate-enzyme activities. Gaining insight into MMP function and tissue specificity is crucial for developing effective drug discovery strategies and novel therapeutics. This requires considering the dynamic cellular processes and consequences of network proteolysis.

Craniofacial and olfactory sensory changes after long-term unilateral nasal obstruction-an animal study using MMP-3-LUC transgenic rats

Nasal obstruction exerts considerable physiological effects on the respiratory system and craniofacial morphology during the developmental stage. This study used MMP-3-LUC transgenic rats for in vivo tracking of long-term expression in the rat nasal region after unilateral nasal obstruction. Skeletal changes of the craniofacial, nasal, and sinus regions were measured through micro-computed tomography examination and analysis with 3D image processing and calculation. Matrix metalloproteinase-3 and olfactory marker protein expression were also investigated through immunohistochemistry (IHC). Unilateral nasal obstruction significantly reduced the MMP-3 signal in the nasal region of MMP-3-LUC transgenic rats, which was mainly expressed in the respiratory epithelium. Long-term obstruction also caused morphological changes of the craniofacial hard tissue, such as nasal septal deviation, longer inter-jaw distance, and increased maxillary molar dental height. It also caused compensatory growth in olfactory nerve bundles and the olfactory epithelium, as confirmed by IHC. In our study, long-term unilateral nasal obstruction caused nasal septal deviation toward the unobstructed side, hyper divergent facial development including longer molar dental height, and reduced MMP-3 production. However, further investigation is necessary to explore the mechanism in depth.

Identification of m6A-Related Biomarkers in Systemic Lupus Erythematosus: A Bioinformation-Based Analysis

Background

Systemic Lupus Erythematosus (SLE), a prototypical autoimmune disorder, presents a challenge due to the absence of reliable biomarkers for discerning organ-specific damage within SLE. A growing body of evidence underscores the pivotal involvement of N6-methyladenosine (m6A) in the etiology of autoimmune conditions.

Methods

The datasets, which primarily encompassed the expression profiles of m6A regulatory genes, were retrieved from the Gene Expression Omnibus (GEO) repository. The optimal model, selected from either Random Forest (RF) or Support Vector Machine (SVM), was employed for the development of a predictive nomogram model. To identify pivotal genes associated with SLE, a comprehensive screening process was conducted utilizing LASSO, SVM-RFE, and RF techniques. Within the realm of SLE susceptibility, Weighted Gene Co-expression Network Analysis (WGCNA) was harnessed to delineate relevant modules and hub genes. Additionally, MeRIP-qPCR assays were performed to elucidate key genes correlated with m6A targets. Furthermore, a Mendelian randomization study was conducted based on genome-wide association studies to assess the causative influence of MMP9 on ischemic stroke (IS), which is not only a severe cerebrovascular event but also a common complication of SLE.

Results

Twelve m6A regulatory genes was identified, demonstrating statistical significance (p < 0.05) and utilized for constructing a nomogram model using the RF algorithm. EPSTI1, USP18, HP, and MMP9, as the hub genes, were identified. MMP9 uniquely correlates with m6A modification and was causally linked to an increased risk of IS, as indicated by our inverse variance weighting analysis showing an odds ratio of 1.0134 (95% CI=1.0004-1.0266, p = 0.0440).

Conclusion

Our study identified twelve m6A regulators, shedding light on the molecular mechanisms underlying SLE risk genes. Importantly, our analysis established a causal relationship between MMP9, a key m6A-related gene, and ischemic stroke, a common complication of SLE, thereby providing critical insights for presymptomatic diagnostic approaches.

Attenuating human fear memory retention with minocycline: a randomized placebo-controlled trial

Pavlovian fear conditioning is widely used as a pre-clinical model to investigate methods for prevention and treatment of anxiety and stress-related disorders. In this model, fear memory consolidation is thought to require synaptic remodeling, which is induced by signaling cascades involving matrix metalloproteinase 9 (MMP-9). Here we investigated the effect of the tetracycline antibiotic minocycline, an inhibitor of MMP-9, on fear memory retention. We conducted a pre-registered, randomized, double-blind, placebo-controlled trial in N = 105 healthy humans (N = 70 female), using a configural fear conditioning paradigm. We administered a single dose of minocycline before configural fear memory acquisition and assessed fear memory retention seven days later in a recall test. To index memory retention, we pre-registered fear-potentially startle (FPS) as our primary outcome, and pupil dilation as the secondary outcome. As control indices of memory acquisition, we analyzed skin conductance responses (SCR) and pupil dilation. We observed attenuated retention of configural fear memory in individuals treated with minocycline compared to placebo, as measured by our primary outcome. In contrast, minocycline did not affect fear memory acquisition or declarative contingency memory. Our findings provide in-vivo evidence for the inhibition of fear memory consolidation by minocycline. This could motivate further research into primary prevention, and given the short uptake time of minocycline, potentially also secondary prevention of PTSD after trauma.

Matrix Metalloproteinase-9 Contributes to Epilepsy Development after Ischemic Stroke in Mice

Epilepsy, a neurological disorder affecting over 50 million individuals globally, is characterized by an enduring predisposition and diverse consequences, both neurobiological and social. Acquired epilepsy, constituting 30% of cases, often results from brain-damaging injuries like ischemic stroke. With one third of epilepsy cases being resistant to existing drugs and without any preventive therapeutics for epileptogenesis, identifying anti-epileptogenic targets is crucial. Stroke being a leading cause of acquired epilepsy, particularly in the elderly, prompts the need for understanding post-stroke epileptogenesis. Despite the challenges in studying stroke-evoked epilepsy in rodents due to poor long-term survival rates, in this presented study the use of an animal care protocol allowed for comprehensive investigation. We highlight the role of matrix metalloproteinase-9 (MMP-9) in post-stroke epileptogenesis, emphasizing MMP-9 involvement in mouse models and its potential as a therapeutic target. Using a focal Middle Cerebral Artery occlusion model, this study demonstrates MMP-9 activation following ischemia, influencing susceptibility to seizures. MMP-9 knockout reduces epileptic features, while overexpression exacerbates them. The findings show that MMP-9 is a key player in post-stroke epileptogenesis, presenting opportunities for future therapies and expanding our understanding of acquired epilepsy.

Network pharmacology and molecular docking to study the potential molecular mechanism of Qi Fu Yin for diabetic encephalopathy

Diabetic encephalopathy is a chronic complication of diabetes that lacks an optimized treatment strategy. The present study sought to elucidate the potential molecular mechanism of Qi Fu Yin in improving diabetic encephalopathy through network pharmacology. The active components and target information of Qi Fu Yin were obtained from the TCMSP and Swiss target databases, while the target information of diabetic encephalopathy was sourced from Gene cards, OMIM, and Pharm Gkb databases. Enrichment analyses of KEGG and GO were conducted utilizing drug-disease common targets, while protein-protein interactions were predicted through the utilization of the STRING database platform. Subsequently, molecular docking was executed via Auto Dock Vina to authenticate the interaction between core components and core targets. The findings revealed that Qi Fu Yin exhibited 178 common targets with diabetic encephalopathy, and the enrichment analyses demonstrated that these targets were associated with lipid and atherosclerosis, AGE-RAGE signaling pathways, and other related pathways. The findings of the molecular docking indicated a favorable binding affinity between the active components of drug and the core targets, with EGF and quercetin exhibiting the most notable docking score. Additionally, the molecular dynamics simulation corroborated this high affinity. These results suggested that the active ingredients of Qi Fu Yin, including quercetin and kaempferol, may modulated the expression of genes such as IL10, TNF, EGF, and MMP2, thereby activating the AGE-RAGE signaling pathways and potentially serving as a therapeutic intervention for diabetic encephalopathy.Communicated by Ramaswamy H. Sarma.

Inhibition of MMP-2 and MMP-9 attenuates surgery-induced cognitive impairment in aged mice

BACKGROUND

The inhibition of matrix metalloproteinases (MMPs) has shown potential in the treatment of various neurodegenerative diseases, and perioperative neurocognitive disorders (PND) is accompanied by the increased expression of MMP-2 and MMP-9 in the hippocampus. However, the effect of inhibiting MMP-2 and MMP-9 on PND is not clear. In this study we aimed to evaluate the effects of inhibiting MMP-2 and MMP-9 on cognitive function in the aged mice after surgery, in order to find a possible target for the prevention and treatment of PND METHODS: In this study, 14-month-old C57BL/6 mice were used to establish a PND model by tibial fracture surgery and sevoflurane anesthesia. Three days later, part of the mice were subjected to cognitive assessment and the other was sacrificed for biochemical analysis. We used the Novel object recognition test and Fear conditioning test to evaluate the postoperative cognitive function of mice. The expression of mmp-2 and MMP-9 was detected by western blotting. We also examined the expression of claudin-5 and occludin using Western blotting, and the activation of microglia and astrocytes using immunofluorescence.

RESULTS

The results showed that surgery increased the expression of MMP-2 and MMP-9 in the hippocampus of mice, accompanied by cognitive impairment, decreased expression of claudin-5 and occludin, and increased activation of microglia and astrocytes. However, inhibition of MMP-2 and MMP-9 expression by SB-3CT reversed these changes.

CONCLUSIONS

Our study shows that inhibition of MMP-2 and MMP-9 alleviates anesthesia/surgery-induced cognitive decline by increasing BBB integrity and inhibiting glial cell activation.

MMP-9 plasma level as biomarker of cochlear implantation outcome in cohort study of deaf children

PURPOSE

If before cochlear implantation it was possible to assay biomarkers of neuroplasticity, we might be able to identify those children with congenital deafness who, later on, were at risk of poor speech and language rehabilitation outcomes.

METHODS

A group of 40 children aged up to 2 years with DFNB1-related congenital deafness was observed in this prospective cohort study over three follow-up intervals (0, 8, and 18 months) after cochlear implant (CI) activation. Children were assessed for auditory development using the LittlEARS Questionnaire (LEAQ) score, and at the same time, measurements were made of matrix metalloproteinase-9 (MMP-9) plasma levels.

RESULTS

There were significant negative correlations between plasma levels of MMP-9 at 8-month follow-up and LEAQ score at cochlear implantation (p = 0.04) and LEAQ score at 18-month follow-up (p = 0.02) and between MMP-9 plasma levels at 18-month follow-up and LEAQ score at cochlear implantation (p = 0.04). As already reported, we confirmed a significant negative correlation between MMP-9 plasma level at cochlear implantation and LEAQ score at 18-month follow-up (p = 0.005). Based on this latter correlation, two clusters of good and poor CI performers could be isolated.

CONCLUSIONS

The study shows that children born deaf who have an MMP-9 plasma level of less than 150 ng/ml at cochlear implantation have a good chance of attaining a high LEAQ score after 18 months of speech and language rehabilitation. This indicates that MMP-9 plasma level at cochlear implantation is a good prognostic marker for CI outcome.

Clinical association study on the matrix metalloproteinase expression in the serum of patients with connective tissue disease complicated with interstitial lung disease

Objectives

This study was implemented to reveal the expression and the clinical correlation of matrix metalloproteinases (MPSs) with connective tissue disease (CTD) complicated with interstitial lung disease (ILD).

Patients and methods

This clinical study was conducted with 260 patients (151 males, 109 females; mean age: 47.3±12.5 years; range, 29 to 67 years) between October 2019 and October 2020. Among the subjects, 100 were CTD patients (CTD group), 80 were CTD patients with ILD (CTD-ILD group) and 80 were healthy individuals (control group). The MMP-2, -3, -7, and -9 levels in the serum of the three groups were detected by enzyme-linked immunosorbent assay.

Results

Serum levels of MMP-3, -7, and -9 in the CTD-ILD group were higher, while the MMP-2 level was lower than those in the CTD group and the control group. The MMP-7 level in the serum of the CTD-ILD group was positively related to C-reactive protein, erythrocyte sedimentation rate, and rheumatoid factor and negatively correlated with immunoglobulin G and complement 3. The MMP-7 expression in the serum was positively correlated with forced expiratory volume in one second (FEV1%), FEV1/forced expiratory volume (FVC), and FVC in CTD-ILD patients. Pearson statistical analysis revealed that there was a significant positive correlation between the MMP-7 expression and the percentage of B cells in the serum of CTD-ILD patients.

Conclusion

Expressions of MMP-3, -7, and -9 are significantly increased in the serum of patients with CTD and related interstitial lung lesions, and the high expression of MMP-7 indicates dynamic lung lesions, which is possible to be used as a possible biomarker for early diagnosis and assessment of disease progression.

Matrix Metalloproteinase-Responsive Drug Delivery Systems

Matrix metalloproteinases (MMPs) are a class of endopeptidases that are dependent on zinc and facilitate the degradation of extracellular matrix (ECM) proteins, thereby playing pivotal parts in human physiology and pathology. MMPs regulate normal tissue and cellular functions, including tissue development, remodeling, angiogenesis, bone formation, and wound healing. Several diseases, including cancer, inflammation, cardiovascular diseases, and nervous system disorders, have been linked to dysregulated expression of specific MMP subtypes, which can promote tumor progression, metastasis, and inflammation. Various MMP-responsive drug delivery and release systems have been developed by harnessing cleavage activities and overexpression of MMPs in affected regions. Herein, we review the structure, substrates, and physiological and pathological functions of various MMPs and highlight the strategies for designing MMP-responsive nanoparticles to improve the targeting efficiency, penetration, and protection of therapeutic payloads.

Bibliometric and visualization analysis of matrix metalloproteinases in ischemic stroke from 1992 to 2022

Background

Matrix metalloproteinases (MMPs) are important players in the complex pathophysiology of ischemic stroke (IS). Recent studies have shown that tremendous progress has been made in the research of MMPs in IS. However, a comprehensive bibliometric analysis is lacking in this research field. This study aimed to introduce the research status as well as hotspots and explore the field of MMPs in IS from a bibliometric perspective.

Methods

This study collected 1,441 records related to MMPs in IS from 1979 to 2022 in the web of science core collection (WoSCC) database, among them the first paper was published in 1992. CiteSpace, VOSviewer, and R package "bibliometrix" software were used to analyze the publication type, author, institution, country, keywords, and other relevant data in detail, and made descriptive statistics to provide new ideas for future clinical and scientific research.

Results

The change in the number of publications related to MMPs in IS can be divided into three stages: the first stage was from 1992 to 2012, when the number of publications increased steadily; the second stage was from 2013 to 2017, when the number of publications was relatively stable; the third stage was from 2018 to 2022, when the number of publications began to decline. The United States and China, contributing more than 64% of publications, were the main drivers for research in this field. Universities in the United States were the most active institutions and contributed the most publications. STROKE is the most popular journal in this field with the largest publications as well as the most co-cited journal. Rosenberg GA was the most prolific writer and has the most citations. "Clinical," "Medical," "Neurology," "Immunology" and "Biochemistry molecular biology" were the main research areas of MMPs in IS. "Molecular regulation," "Metalloproteinase-9 concentration," "Clinical translation" and "Cerebral ischemia-reperfusion" are the primary keywords clusters in this field.

Conclusion

This is the first bibliometric study that comprehensively mapped out the knowledge structure and development trends in the research field of MMPs in IS in recent 30 years, which will provide a reference for scholars studying this field.

A potential relationship between MMP-9 rs2250889 and ischemic stroke susceptibility

Purpose

Ischemic stroke (IS), a serious cerebrovascular disease, greatly affects people's health and life. Genetic factors are indispensable for the occurrence of IS. As a biomarker for IS, the MMP-9 gene is widely involved in the pathophysiological process of IS. This study attempts to find out the relationship between MMP-9 polymorphisms and IS susceptibility.

Methods

A total of 700 IS patients and 700 healthy controls were recruited. The single nucleotide polymorphism (SNP) markers of the MMP-9 gene were genotyped by the MassARRAY analyzer. Multifactor dimensionality reduction (MDR) was applied to generate SNP-SNP interaction. Furthermore, the relationship between genetic variations (allele and genotype) of the MMP-9 gene and IS susceptibility was analyzed by calculating odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Our results demonstrated that rs2250889 could significantly increase the susceptibility to IS in the codominant, dominant, overdominant, and log-additive models (p < 0.05). Further stratification analysis showed that compared with the control group, rs2250889 was associated with IS risk in different case groups (age, female, smoking, and non-drinking) (p < 0.05). Based on MDR analysis, rs2250889 was the best model for predicting IS risk (cross-validation consistency: 10/10, OR = 1.56 (1.26-1.94), p < 0.001).

Conclusion

Our study preliminarily confirmed that SNP rs2250889 was significantly associated with susceptibility to IS.

Dynamic regulation of the extracellular matrix in reward memory processes: a question of time

Substance use disorders are a global health problem with increasing prevalence resulting in significant socioeconomic burden and increased mortality. Converging lines of evidence point to a critical role of brain extracellular matrix (ECM) molecules in the pathophysiology of substance use disorders. An increasing number of preclinical studies highlight the ECM as a promising target for development of novel cessation pharmacotherapies. The brain ECM is dynamically regulated during learning and memory processes, thus the time course of ECM alterations in substance use disorders is a critical factor that may impact interpretation of the current studies and development of pharmacological therapies. This review highlights the evidence for the involvement of ECM molecules in reward learning, including drug reward and natural reward such as food, as well as evidence regarding the pathophysiological state of the brain's ECM in substance use disorders and metabolic disorders. We focus on the information regarding time-course and substance specific changes in ECM molecules and how this information can be leveraged for the development of therapeutic strategies.

Exploring brain glutathione and peripheral blood markers in posttraumatic stress disorder: a combined [1H]MRS and peripheral blood study

Introduction

Oxidative stress has been implicated in psychiatric disorders, including posttraumatic stress disorder (PTSD). Currently, the status of glutathione (GSH), the brain's most abundant antioxidant, in PTSD remains uncertain. Therefore, the current study investigated brain concentrations of GSH and peripheral concentrations of blood markers in individuals with PTSD vs. Healthy Controls (HC).

Methods

GSH spectra was acquired in the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (DLPFC) using MEGA-PRESS, a J-difference-editing acquisition method. Peripheral blood samples were analyzed for concentrations of metalloproteinase (MMP)-9, tissue inhibitors of MMP (TIMP)-1,2, and myeloperoxidase (MPO).

Results

There was no difference in GSH between PTSD and HC in the ACC (n = 30 PTSD, n = 20 HC) or DLPFC (n = 14 PTSD, n = 18 HC). There were no group differences between peripheral blood markers (P > 0.3) except for (non-significantly) lower TIMP-2 in PTSD. Additionally, TIMP-2 and GSH in the ACC were positively related in those with PTSD. Finally, MPO and MMP-9 were negatively associated with duration of PTSD.

Conclusions

We do not report altered GSH concentrations in the ACC or DLPFC in PTSD, however, systemic MMPs and MPO might be implicated in central processes and progression of PTSD. Future research should investigate these relationships in larger sample sizes.

Identification of the matrix metalloproteinase (MMP) gene family in Japanese flounder (Paralichthys olivaceus): Involved in immune response regulation to temperature stress and Edwardsiella tarda infection

The Matrix metalloproteinase (MMP) gene family is responsible for regulating the degradation of Extra Cellular Matrix (ECM) proteins, which are important for physiological processes such as wound healing, tissue remodeling, and stress response. Although MMPs have been studied in many species, their role in immune response in Japanese flounder (Paralichthys olivaceus) is still not fully understood. This study conducted a comprehensive analysis of MMPs in flounder, including gene structures, evolutionary relationships, conserved domains, molecular evolution, and expression patterns. Analysis revealed that MMP genes could be grouped into 17 subfamilies and were evolutionarily conserved and functionally-constrained. Meanwhile, MMP genes were found to express in different embryonic and larval stages and might play the role of sentinel in healthy tissues. Furthermore, expression profiling showed that MMPs had diverse functions in environmental stress, with 60% (9/15) and 73% (11/15) of MMPs showing differential expression patterns under temperature stress and Edwardsiella tarda (E. tarda) infection, respectively. These findings provide a useful resource for understanding the immune functions of MMP genes in Japanese flounder.

Muscarinic Cholinergic Receptor Antagonism Impairs Spatial Memory Retrieval and Minimizes Retrieval-Induced Alterations in Matrix Metalloproteinase-9

Cholinergic dysfunction in the hippocampus causes memory impairment, and degradation of the forebrain cholinergic system has been implicated in several neurological disorders. One such disorder, Alzheimer's Disease (AD) is associated with the abnormal expression of various proteins including matrix metalloproteinase-9 (MMP-9), an enzyme known to regulate hippocampus-dependent memory. Memory involves several stages including acquisition, consolidation, and retrieval, but the neurobiological correlates of retrieval have been studied much less than other stages of memory. We sought to investigate the potential relationship between cholinergic signaling and hippocampal MMP-9 expression and the involvement of each in spatial memory retrieval. We trained rats in the water maze until the task was well-learned, then, seven days later, we allowed some to retrieve the memory after an intracerebroventricular injection of scopolamine or vehicle. Western blot analysis of hippocampal tissue shows elevated levels of a truncated form of MMP-9 associated with spatial memory retrieval. Additionally, our results indicate that centrally administered scopolamine both impairs spatial memory retrieval and prevents retrieval-induced elevations in MMP-9. These findings provide evidence for a potential link between cholinergic dysregulation and abnormal MMP-9 levels seen in the brains of AD patients. An important, yet unresolved question is whether MMP-9 serves to support memory retrieval itself or if it is involved in maintaining the ongoing stability of a retrieved memory.

Potential Biomarkers of Impulsivity in Mild Traumatic Brain Injury: A Pilot Study

Very few studies have investigated cognition and impulsivity following mild traumatic brain injury (mTBI) in the general population. Furthermore, the neurobiological mechanisms underlying post-TBI neurobehavioral syndromes are complex and remain to be fully clarified. Herein, we took advantage of machine learning based-modeling to investigate potential biomarkers of mTBI-associated impulsivity. Twenty-one mTBI patients were assessed within one-month post-TBI and their data were compared to 19 healthy controls on measures of impulsivity (Barratt Impulsiveness Scale - BIS), executive functioning, episodic memory, self-report cognitive failures and blood biomarkers of inflammation, vascular and neuronal damage. mTBI patients were significantly more impulsive than controls in BIS total and subscales. Serum levels of sCD40L, Cathepsin D, IL-4, Neuropilin-1, IFN-α2, and Copeptin were associated with impulsivity in mTBI patients. Besides showing that mTBI are associated with impulsivity in non-military people, we unveiled different pathophysiological pathways potentially implicated in mTBI-related impulsivity.

Environmental conditions of recognition memory testing induce neurovascular changes in the hippocampus in a sex-specific manner in mice

Experiences are linked to emotions impacting memory consolidation and associated brain neuronal circuits. Posttraumatic stress disorder is an example of strong negative emotions affecting memory processes by flashbacks of past traumas. Stress-related memory deficits are also observed in major depressive disorder (MDD). We recently highlighted that sex-specific blood-brain barrier (BBB) alterations underlie stress responses in mice and human depression. However, little is known about the relationship between emotional valence, memory encoding and BBB gene expression. Here, we investigated the effects of novel object recognition (NOR) test, an experience considered of neutral emotional valence, on BBB properties in dorsal vs ventral hippocampus (HIPP) in the context of various environmental conditions (arena size, handling, age). The HIPP is a brain area central for learning and memory processes with the dorsal and ventral subregions being associated with working memory vs reference memory retrieval, respectively. Expression of genes related to BBB integrity are altered in line with learning and memory processes in a region- and sex-specific manner. We observed correlations between poor learning, anxiety, stress-induced corticosterone release and changes in BBB-associated gene expression. Comparison of BBB transcriptomes between sexes also revealed profound differences at baseline in both ventral and dorsal HIPP. Finally, we identified circulating vascular biomarkers, such as sE-selectin and matrix metallopeptidase 9 (MMP-9), altered following NOR exposure supporting that recognition memory formation has an impact on the neurovasculature. Although deemed as a neutral valence test, NOR experimental conditions can shift it toward a negative valence, impacting performance and highlighting the need to minimize anxiety when performing this commonly used test in mice.

Ischemia Reperfusion Injury Induced Blood Brain Barrier Dysfunction and the Involved Molecular Mechanism

Stroke is characterized by the abrupt failure of blood flow to a specific brain region, resulting in insufficient supply of oxygen and glucose to the ischemic tissues. Timely reperfusion of blood flow can rescue dying tissue but can also lead to secondary damage to both the infarcted tissues and the blood-brain barrier, known as ischemia/reperfusion injury. Both primary and secondary damage result in biphasic opening of the blood-brain barrier, leading to blood-brain barrier dysfunction and vasogenic edema. Importantly, blood-brain barrier dysfunction, inflammation, and microglial activation are critical factors that worsen stroke outcomes. Activated microglia secrete numerous cytokines, chemokines, and inflammatory factors during neuroinflammation, contributing to the second opening of the blood-brain barrier and worsening the outcome of ischemic stroke. TNF-α, IL-1β, IL-6, and other microglia-derived molecules have been shown to be involved in the breakdown of blood-brain barrier. Additionally, other non-microglia-derived molecules such as RNA, HSPs, and transporter proteins also participate in the blood-brain barrier breakdown process after ischemic stroke, either in the primary damage stage directly influencing tight junction proteins and endothelial cells, or in the secondary damage stage participating in the following neuroinflammation. This review summarizes the cellular and molecular components of the blood-brain barrier and concludes the association of microglia-derived and non-microglia-derived molecules with blood-brain barrier dysfunction and its underlying mechanisms.

Matrix metalloproteinase-9 overexpression in the hippocampus reduces alcohol-induced conditioned-place preference by regulating synaptic plasticity in mice

Extracellular matrix proteins appear to be necessary for the synaptic plasticity that underlies addiction memory. In the brain, matrix metalloproteinases (MMPs), especially matrix metalloproteinase-9 (MMP-9), have been recently implicated in processes involving alcohol reward and memory. Here, we showed for the first time, the positive effects of MMP-9 on alcohol-induced conditioned place preference (CPP) behavior and hippocampal neuron plasticity in C57BL/6 mice. Using recombinant adeno-associated viruses to overexpress MMP-9 in the hippocampus, we investigated the NMDAR, PSD-95, and cellular cytoskeleton proteins F-actin/G-actin in the modulation of alcohol reward behavior in mice exposed to CPP. We found that hippocampal infusions of MMP-9 decreased alcohol-induced place preference suggesting a reduction in alcohol reward. Western blot analysis demonstrated that protein expression of NMDA receptors (GluN1, GluN2A and GluN2B) in the hippocampus of alcohol-exposed mice were higher than that of the saline group. Further, the expression of these proteins was decreased in MMP-9 overexpressing mice. MMP-9 also regulated the ratio of F-actin/G-actin (dendritic spines cytoskeleton proteins), which might be the key mediator for behavioral changes in mice. Consequently, our results highlight new evidence that MMP-9 may play an important role in the molecular mechanism underlying alcohol reward and preference.

Inhibition of matrix metalloproteinases by HIV-1 integrase strand transfer inhibitors

More than fifteen million women with the human immunodeficiency virus type-1 (HIV-1) infection are of childbearing age world-wide. Due to improved and affordable access to antiretroviral therapy (ART), the number of in utero antiretroviral drug (ARV)-exposed children has exceeded a million and continues to grow. While most recommended ART taken during pregnancy suppresses mother to child viral transmission, the knowledge of drug safety linked to fetal neurodevelopment remains an area of active investigation. For example, few studies have suggested that ARV use can be associated with neural tube defects (NTDs) and most notably with the integrase strand transfer inhibitor (INSTI) dolutegravir (DTG). After risk benefit assessments, the World Health Organization (WHO) made recommendations for DTG usage as a first and second-line preferred treatment for infected populations including pregnant women and those of childbearing age. Nonetheless, long-term safety concerns remain for fetal health. This has led to a number of recent studies underscoring the need for biomarkers to elucidate potential mechanisms underlying long-term neurodevelopmental adverse events. With this goal in mind, we now report the inhibition of matrix metalloproteinases (MMPs) activities by INSTIs as an ARV class effect. Balanced MMPs activities play a crucial role in fetal neurodevelopment. Inhibition of MMPs activities by INSTIs during neurodevelopment could be a potential mechanism for adverse events. Thus, comprehensive molecular docking testing of the INSTIs, DTG, bictegravir (BIC), and cabotegravir (CAB), against twenty-three human MMPs showed broad-spectrum inhibition. With a metal chelating chemical property, each of the INSTI were shown to bind Zn++ at the MMP's catalytic domain leading to MMP inhibition but to variable binding energies. These results were validated in myeloid cell culture experiments demonstrating MMP-2 and 9 inhibitions by DTG, BIC and CAB and even at higher degree than doxycycline (DOX). Altogether, these data provide a potential mechanism for how INSTIs could affect fetal neurodevelopment.

Longitudinal Changes in BDNF and MMP-9 Protein Plasma Levels in Children after Cochlear Implantation

Congenitally deaf children who undergo cochlear implantation before 1 year of age develop their auditory skills faster than children who are implanted later. In this longitudinal study, a cohort of 59 implanted children were divided into two subgroups according to their ages at implantation-below or above 1 year old-and the plasma levels of matrix metalloproteinase-9 (MMP-9), brain-derived neurotrophic factor (BDNF), and pro-BDNF were measured at 0, 8, and 18 months after cochlear implant activation, while auditory development was simultaneously evaluated using the LittlEARs Questionnaire (LEAQ). A control group consisted of 49 age-matched healthy children. We identified statistically higher BDNF levels at 0 months and at the 18-month follow-ups in the younger subgroup compared to the older one and lower LEAQ scores at 0 months in the younger subgroup. Between the subgroups, there were significant differences in the changes in BDNF levels from 0 to 8 months and in LEAQ scores from 0 to 18 months. The MMP-9 levels significantly decreased from 0 to 18 months and from 0 to 8 months in both subgroups and from 8 to 18 months only in the older one. For all measured protein concentrations, significant differences were identified between the older study subgroup and the age-matched control group.

The regulatory function of lncRNA and constructed network in epilepsy

BACKGROUND

Epilepsy is a neurological disease characterized by neural network dysfunction. Although most reports indicate that the pathological process of epilepsy is related to inflammation, synaptic plasticity, cell apoptosis, and ion channel dysfunction, the underlying molecular mechanisms of epilepsy are not fully understood.

METHODS

This review summarizes the latest literature on the roles and characteristics of long noncoding RNAs (lncRNAs) in the pathogenesis of epilepsy.

RESULTS

lncRNAs are a class of long transcripts without protein-coding functions that perform important regulatory functions in various biological processes. lncRNAs are involved in the regulation of the pathological process of epilepsy and are abnormally expressed in both patients and animal models. This review provides an overview of research progress in epilepsy, the multifunctional features of lncRNAs, the lncRNA expression pattern related to epileptogenesis and status epilepticus, and the potential mechanisms for the two interactions contributing to epileptogenesis and progression.

CONCLUSION

lncRNAs can serve as new diagnostic markers and therapeutic targets for epilepsy in the future.

Effect of the Matrix Metalloproteinase Inhibitor Doxycycline on Human Trace Fear Memory

Learning to predict threat is of adaptive importance, but aversive memory can also become disadvantageous and burdensome in clinical conditions such as posttraumatic stress disorder (PTSD). Pavlovian fear conditioning is a laboratory model of aversive memory and thought to rely on structural synaptic reconfiguration involving matrix metalloproteinase (MMP)9 signaling. It has recently been suggested that the MMP9-inhibiting antibiotic doxycycline, applied before acquisition training in humans, reduces fear memory retention after one week. This previous study used cued delay fear conditioning, in which predictors and outcomes overlap in time. However, temporal separation of predictors and outcomes is common in clinical conditions. Learning the association of temporally separated events requires a partly different neural circuitry, for which the role of MMP9 signaling is not yet known. Here, we investigate the impact of doxycycline on long-interval (15 s) trace fear conditioning in a randomized controlled trial with 101 (50 females) human participants. We find no impact of the drug in our preregistered analyses. Exploratory post hoc analyses of memory retention suggested a serum level-dependent effect of doxycycline on trace fear memory retention. However, effect size to distinguish CS+/CS- in the placebo group turned out to be smaller than in previously used delay fear conditioning protocols, which limits the power of statistical tests. Our results suggest that doxycycline effect on trace fear conditioning in healthy individuals is smaller and less robust than anticipated, potentially limiting its clinical application potential.

Circulating Proteins Influencing Psychiatric Disease: A Mendelian Randomization Study

BACKGROUND

There is a pressing need for novel drug targets for psychiatric disorders. Circulating proteins are potential candidates because they are relatively easy to measure and modulate and play important roles in signaling.

METHODS

We performed two-sample Mendelian randomization analyses to estimate the associations between circulating protein abundances and risk of 10 psychiatric disorders. Genetic variants associated with 1611 circulating protein abundances identified in 6 large-scale proteomic studies were used as genetic instruments. Effects of the circulating proteins on psychiatric disorders were estimated by Wald ratio or inverse variance-weighted ratio tests. Horizontal pleiotropy, colocalization, and protein-altering effects were examined to validate the assumptions of Mendelian randomization.

RESULTS

Nine circulating protein-to-disease associations withstood multiple sensitivity analyses. Among them, 2 circulating proteins had associations replicated in 3 proteomic studies. A 1 standard deviation increase in the genetically predicted circulating TIMP4 level was associated with a reduced risk of anorexia nervosa (minimum odds ratio [OR] = 0.83; 95% CI, 0.76-0.91) and bipolar disorder (minimum OR = 0.88; 95% CI, 0.82-0.94). A 1 standard deviation increase in the genetically predicted circulating ESAM level was associated with an increased risk of schizophrenia (maximum OR = 1.32; 95% CI, 1.22-1.43). In addition, 58 suggestive protein-to-disease associations warrant validation with observational or experimental evidence. For instance, a 1 standard deviation increase in the ERLEC1-201-to-ERLEC1-202 splice variant ratio was associated with a reduced risk of schizophrenia (OR = 0.94; 95% CI, 0.90-0.97).

CONCLUSIONS

Prioritized circulating proteins appear to influence the risk of psychiatric disease and may be explored as intervention targets.

Does the functional polymorphism-1562C/T of MMP-9 gene influence brain disorders?

Metalloproteinase-9 (MMP-9) is one of the most strongly expressed matrix metalloproteinases (MMPs) in the brain. The MMP-9 activity in the brain is strictly regulated, and any disruptions in this regulation contribute to a development of many disorders of the nervous system including multiple sclerosis, brain strokes, neurodegenerative disorders, brain tumors, schizophrenia, or Guillain-Barré syndrome. This article discusses a relationship between development of the nervous system diseases and the functional single nucleotide polymorphism (SNP) at position -1562C/T within the MMP-9 gene. A pathogenic influence of MMP-9-1562C/T SNP was observed both in neurological and psychiatric disorders. The presence of the allele T often increases the activity of the MMP-9 gene promoter and consequently the expression of MMP-9 when compared to the allele C. This leads to a change in the likelihood of an occurrence of diseases and modifies the course of certain brain diseases in humans, as discussed below. The presented data indicates that the MMP-9-1562C/T functional polymorphism influences the course of many neuropsychiatric disorders in humans suggesting a significant pathological role of the MMP-9 metalloproteinase in pathologies of the human central nervous system.

Gene Therapy for Neuropsychiatric Disorders: Potential Targets and Tools

Neuropsychiatric disorders that affect the central nervous system cause considerable pressures on the health care system and have a substantial economic burden on modern societies. The present treatments based on available drugs are mostly ineffective and often costly. The molecular process of neuropsychiatric disorders is closely connected to modifying the genetic structures inherited or caused by damage, toxic chemicals, and some current diseases. Gene therapy is presently an experimental concept for neurological disorders. Clinical applications endeavor to alleviate the symptoms, reduce disease progression, and repair defective genes. Implementing gene therapy in inherited and acquired neurological illnesses entails the integration of several scientific disciplines, including virology, neurology, neurosurgery, molecular genetics, and immunology. Genetic manipulation has the power to minimize or cure illness by inducing genetic alterations at endogenous loci. Gene therapy that involves treating the disease by deleting, silencing, or editing defective genes and delivering genetic material to produce therapeutic molecules has excellent potential as a novel approach for treating neuropsychiatric disorders. With the recent advances in gene selection and vector design quality in targeted treatments, gene therapy could be an effective approach. This review article will investigate and report the newest and the most critical molecules and factors in neuropsychiatric disorder gene therapy. Different genome editing techniques available will be evaluated, and the review will highlight preclinical research of genome editing for neuropsychiatric disorders while also evaluating current limitations and potential strategies to overcome genome editing advancements.

A Potential Role for Neuroinflammation in ADHD

Attention deficit hyperactivity disorder (ADHD) is a neurobehavioural disorder in children and adolescents. Although increases in oxidative stress and disturbances of neurotransmitter system such as the dopaminergic and abnormalities in several brain regions have been demonstrated, the pathophysiology of ADHD is not fully understood. Nevertheless, ADHD involves several factors that have been associated with an increase in neuroinflammation. This chapter presents an overview of factors that may increase neuroinflammation and play a potential role in the development and pathophysiology of ADHD. The altered immune response, polymorphisms in inflammatory-related genes, ADHD comorbidity with autoimmune and inflammatory disorders and prenatal exposure to inflammation are associated with alterations in offspring brain development and are a risk factor; genetic and environmental risk factors that may increase the risk for ADHD and medications can increase neuroinflammation. Evidence of an association between these factors has been an invaluable tool for research on inflammation in ADHD. Therefore, evidence studies have made it possible to generate alternative therapeutic interventions using natural products as anti-inflammatories that could have great potential against neuroinflammation in ADHD.

HIV-1 Integrase Strand Transfer Inhibitors and Neurodevelopment

Children born to mothers, with or at risk, of human immunodeficiency virus type-1 (HIV-1) infection are on the rise due to affordable access of antiretroviral therapy (ART) to pregnant women or those of childbearing age. Each year, up to 1.3 million HIV-1-infected women on ART have given birth with recorded mother-to-child HIV-1 transmission rates of less than 1%. Despite this benefit, the outcomes of children exposed to antiretroviral drugs during pregnancy, especially pre- and post- natal neurodevelopment remain incompletely understood. This is due, in part, to the fact that pregnant women are underrepresented in clinical trials. This is underscored by any potential risks of neural tube defects (NTDs) linked, in measure, to periconceptional usage of dolutegravir (DTG). A potential association between DTG and NTDs was first described in Botswana in 2018. Incidence studies of neurodevelopmental outcomes associated with DTG, and other integrase strand transfer inhibitors (INSTIs) are limited as widespread use of INSTIs has begun only recently in pregnant women. Therefore, any associations between INSTI use during pregnancy, and neurodevelopmental abnormalities remain to be explored. Herein, United States Food and Drug Administration approved ARVs and their use during pregnancy are discussed. We provide updates on INSTI pharmacokinetics and adverse events during pregnancy together with underlying mechanisms which could affect fetal neurodevelopment. Overall, this review seeks to educate both clinical and basic scientists on potential consequences of INSTIs on fetal outcomes as a foundation for future scientific investigations.

Promoting Effect and Potential Mechanism of Lactobacillus pentosus LPQ1-Produced Active Compounds on the Secretion of 5-Hydroxytryptophan

5-hydroxytryptophan (5-HTP) is an important substance thought to improve depression. It has been shown that Lactobacillus can promote the secretion of 5-HTP in the body and thus ameliorate depression-like behavior in mice. However, the mechanism by which Lactobacillus promotes the secretion of 5-HTP is unclear. In this study, we investigated the promoting effect and mechanism of Lactobacillus, isolated from Chinese fermented foods, on the secretion of 5-HTP. The results showed that Lactobacillus (L.) pentosus LPQ1 exhibited the strongest 5-HTP secretion-promoting effect ((9.44 ± 0.69)-fold), which was dependent on the mixture of compounds secreted by L. pentosus LPQ1 (termed SLPQ1). In addition, the results of the RNA sequencing (RNA-seq) and quantitative real-time polymerase chain reaction (qRT-PCR) analyses indicated that SLPQ1 alters the TNF and oxidative phosphorylation signaling pathways. Moreover, the SLPQ1 ultrafiltration fraction (>10 kDa) showed a similar 5-HTP promoting effect as SLPQ1. Furthermore, reverse-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) identified 29 compounds of >10 kDa in SLPQ1, including DUF488 domain-containing protein, BspA family leucine-rich repeat surface protein, and 30S ribosomal protein S5, which together accounted for up to 62.51%. This study reports new findings on the mechanism by which L. pentosus LPQ1 promotes 5-HTP production in some cell lines in vitro.

Exploring the Potential Mechanism of Danshen in the Treatment of Concurrent Ischemic Heart Disease and Depression Using Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

Objective: This study aimed to explore the potential targets and mechanism of action of Danshen in treating concurrent ischemic heart disease (IHD) and depression using network pharmacology, molecular docking, and molecular dynamics simulation (MDS). Methods: The Traditional Chinese Medicine Systems Pharmacology (TCMSP) database was used to obtain active ingredients and targets of Danshen. Candidate targets for IHD and depression were obtained from the Genecards and DisGeNet databases. The protein–protein interaction (PPI) network was constructed using the STRING database and the Cytoscape 3.8.2 software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using the Metascape database and the GlueGO package of the Cytoscape 3.8.2 software. Molecular docking was performed using Autodock 1.5.6 and Vina, and the MDS was completed using GROMACS 5.1.2. Results: We obtained 65 active ingredients of Danshen with 131 candidate targets and 39 intersection targets of the active ingredients and diseases. Luteolin, tanshinone IIA, and salviolone were the core active ingredients, and AKT1, TNF, IL-6, MMP9, CASP3, IL-10, PTGS2, STAT3, PPARG, IL-4, EGFR, MAPK14, NOS3, and EDN1 were the core targets. The GO and KEGG pathway enrichment analyses revealed that the intersection targets were mainly enriched in positive regulation of protein phosphorylation, blood circulation, IL-17 signaling pathway, VEGF signaling pathway, and JAK/STAT signaling pathway. The molecular docking revealed that the core active ingredients had a good affinity for the core targets. The results of MDS revealed that the protein-ligand complexes were stable. Conclusions: This study used network pharmacology to analyze the potential mechanism of action of Danshen in the treatment of concurrent IHD and depression. Additionally, the study provided a theoretical basis for further studying the pharmacological mechanisms and targets of Danshen.