MMP-2: A modulator of neuronal precursor activity and cognitive and motor behaviors

Association between elevated serum matrix metalloproteinase-2 and tumor necrosis factor-α, and clinical symptoms in male patients with treatment-resistant and chronic medicated schizophrenia

BACKGROUND

Inflammation has an important role in the pathogenesis of schizophrenia. The aim of this study was to investigate the levels of tumor necrosis factor (TNF) and matrix metalloproteinase-2 (MMP-2) in male patients with treatment-resistant schizophrenia (TRS) and chronic medicated schizophrenia (CMS), and the relationship with psychopathology.

METHODS

The study enrolled 31 TRS and 49 cm male patients, and 53 healthy controls. Serum MMP-2 and TNF-α levels were measured by the Luminex liquid suspension chip detection method. Positive and Negative Syndrome Scale (PANSS) scores were used to evaluate symptom severity and Repeatable Battery for the Assessment of Neuropsychological Status was used to assess cognitive function.

RESULTS

Serum TNF-α and MMP-2 levels differed significantly between TRS, CMS and healthy control patients (F = 4.289, P = 0.016; F = 4.682, P = 0.011, respectively). Bonferroni correction demonstrated that serum TNF-α levels were significantly elevated in CMS patients (P = 0.022) and MMP-2 levels were significantly higher in TRS patients (P = 0.014) compared to healthy controls. In TRS patients, TNF-α was negatively correlated with age (r=-0.435, P = 0.015) and age of onset (r=-0.409, P = 0.022). In CMS patients, MMP-2 and TNF-α were negatively correlated with PANSS negative and total scores, and TNF-α was negatively correlated with PANSS general psychopathology scores (all P < 0.05). MMP-2 levels were positively correlated with TNF-α levels (P < 0.05), but not with cognitive function (P > 0.05).

CONCLUSION

The results indicate the involvement of inflammation in the etiology of TRS and CMS. Further studies are warranted.

Impaired T3 uptake and action in MCT8-deficient cerebral organoids underlie Allan-Herndon-Dudley syndrome

Patients with mutations in the thyroid hormone (TH) cell transporter monocarboxylate transporter 8 (MCT8) gene develop severe neuropsychomotor retardation known as Allan-Herndon-Dudley syndrome (AHDS). It is assumed that this is caused by a reduction in TH signaling in the developing brain during both intrauterine and postnatal developmental stages, and treatment remains understandably challenging. Given species differences in brain TH transporters and the limitations of studies in mice, we generated cerebral organoids (COs) using human induced pluripotent stem cells (iPSCs) from MCT8-deficient patients. MCT8-deficient COs exhibited (i) altered early neurodevelopment, resulting in smaller neural rosettes with thinner cortical units, (ii) impaired triiodothyronine (T3) transport in developing neural cells, as assessed through deiodinase-3-mediated T3 catabolism, (iii) reduced expression of genes involved in cerebral cortex development, and (iv) reduced T3 inducibility of TH-regulated genes. In contrast, the TH analogs 3,5-diiodothyropropionic acid and 3,3',5-triiodothyroacetic acid triggered normal responses (induction/repression of T3-responsive genes) in MCT8-deficient COs, constituting proof of concept that lack of T3 transport underlies the pathophysiology of AHDS and demonstrating the clinical potential for TH analogs to be used in treating patients with AHDS. MCT8-deficient COs represent a species-specific relevant preclinical model that can be utilized to screen drugs with potential benefits as personalized therapeutics for patients with AHDS.

Neuronal actin cytoskeleton gain of function in the human brain

BACKGROUND

While advancements in imaging techniques have led to major strides in deciphering the human brain, successful interventions are elusive and represent some of the most persistent translational gaps in medicine. Human restricted CHRFAM7A has been associated with neuropsychiatric disorders.

METHODS

The physiological role of CHRFAM7A in human brain is explored using multiomics approach on 600 post mortem human brain tissue samples. The emerging pathways and mechanistic hypotheses are tested and validated in an isogenic hiPSC model of CHRFAM7A knock-in medial ganglionic eminence progenitors and neurons.

FINDINGS

CHRFAM7A is identified as a modulator of intracellular calcium dynamics and an upstream regulator of Rac1. Rac1 activation re-designs the actin cytoskeleton leading to dynamic actin driven remodeling of membrane protrusion and a switch from filopodia to lamellipodia. The reinforced cytoskeleton leads to an advantage to tolerate stiffer mechanical properties of the extracellular environment.

INTERPRETATION

CHRFAM7A modifies the actin cytoskeleton to a more dynamic and stiffness resistant state in an α7nAChR dependent manner. CHRFAM7A may facilitate neuronal adaptation to changes in the brain environment in physiological and pathological conditions contributing to risk or recovery. Understanding how CHRFAM7A affects human brain requires human studies in the areas of memory formation and erasure, cognitive reserve, and neuronal plasticity.

FUNDING

This work is supported in part by the Community Foundation for Greater Buffalo (Kinga Szigeti). Also, in part by the International Society for Neurochemistry (ISN) and The Company of Biologists (Nicolas Rosas). ROSMAP is supported by NIA grants P30AG10161, P30AG72975, R01AG15819, R01AG17917. U01AG46152, and U01AG61356.

Olfactory detection of viruses shapes brain immunity and behavior in zebrafish

Olfactory sensory neurons (OSNs) are constantly exposed to pathogens, including viruses. However, serious brain infection via the olfactory route rarely occurs. When OSNs detect a virus, they coordinate local antiviral immune responses to stop virus progression to the brain. Despite effective immune control in the olfactory periphery, pathogen-triggered neuronal signals reach the CNS via the olfactory bulb (OB). We hypothesized that neuronal detection of a virus by OSNs initiates neuroimmune responses in the OB that prevent pathogen invasion. Using zebrafish ( Danio rerio ) as a model, we demonstrate viral-specific neuronal activation of OSNs projecting into the OB, indicating that OSNs are electrically activated by viruses. Further, behavioral changes are seen in both adult and larval zebrafish after viral exposure. By profiling the transcription of single cells in the OB after OSNs are exposed to virus, we found that both microglia and neurons enter a protective state. Microglia and macrophage populations in the OB respond within minutes of nasal viral delivery followed decreased expression of neuronal differentiation factors and enrichment of genes in the neuropeptide signaling pathway in neuronal clusters. Pituitary adenylate-cyclase-activating polypeptide ( pacap ), a known antimicrobial, was especially enriched in a neuronal cluster. We confirm that PACAP is antiviral in vitro and that PACAP expression increases in the OB 1 day post-viral treatment. Our work reveals how encounters with viruses in the olfactory periphery shape the vertebrate brain by inducing antimicrobial programs in neurons and by altering host behavior.

An Alzheimer’s Disease Patient-Derived Olfactory Stem Cell Model Identifies Gene Expression Changes Associated with Cognition

An early symptom of Alzheimer’s disease (AD) is an impaired sense of smell, for which the molecular basis remains elusive. Here, we generated human olfactory neurosphere-derived (ONS) cells from people with AD and mild cognitive impairment (MCI), and performed global RNA sequencing to determine gene expression changes. ONS cells expressed markers of neuroglial differentiation, providing a unique cellular model to explore changes of early AD-associated pathways. Our transcriptomics data from ONS cells revealed differentially expressed genes (DEGs) associated with cognitive processes in AD cells compared to MCI, or matched healthy controls (HC). A-Kinase Anchoring Protein 6 (AKAP6) was the most significantly altered gene in AD compared to both MCI and HC, and has been linked to cognitive function. The greatest change in gene expression of all DEGs occurred between AD and MCI. Gene pathway analysis revealed defects in multiple cellular processes with aging, intellectual deficiency and alternative splicing being the most significantly dysregulated in AD ONS cells. Our results demonstrate that ONS cells can provide a cellular model for AD that recapitulates disease-associated differences. We have revealed potential novel genes, including AKAP6 that may have a role in AD, particularly MCI to AD transition, and should be further examined.

Occlusal problems, mental health issues and non-carious cervical lesions

Non-carious cervical lesions (NCCLs) are characterized by a loss of hard dental tissue near the cement-enamel junction with multifactorial etiology. The aim of this study was to demonstrate that occlusal factors as attrition, malocclusion, and bruxism, and mental disorders as depression, stress, and anxiety are involved in the etiology of NCCLs. Salivary samples and clinical data of 340 individuals selected from 6,112 participants were obtained from the University of Pittsburgh School of Dental Medicine Dental Registry and DNA Repository project. The affected group was formed by individuals with NCCL (34 females, 34 males, mean age 55.34 years). In addition, the comparison group was formed by individuals without NCCL (136 females, 136 males, mean age 55.14 years). Eleven single-nucleotide polymorphisms (SNPs) previously associated with mental disorders were genotyped and tested for association with NCCLs. When all occlusal factors were combined there was found a significant association with NCCL (p = 0.000001/adjusted OR 4.38, 95% CI 2.50-7.69). Attrition (OR 3.56, 95% CI 2.00-6.32) and malocclusion (OR 5.09, 95% CI 1.65-15.68) as separate variables showed statistically significant associations with NCCL. There was a significant difference in stress history between the two groups (OR 2.17, 95% CI 1.08-4.39). No associations between NCCLs and the SNPs selected were found. However, when the occlusal factors were analyzed as covariates, associations were found between bruxism and seven of the selected SNPs. Our results suggest that occlusal factors might be associated with NCCLs.

Transcriptional networks identify synaptotagmin-like 3 as a regulator of cortical neuronal migration during early neurodevelopment

Human brain development is a complex process involving neural proliferation, differentiation, and migration that are directed by many essential cellular factors and drivers. Here, using the NetBID2 algorithm and developing human brain RNA sequencing dataset, we identify synaptotagmin-like 3 (SYTL3) as one of the top drivers of early human brain development. Interestingly, SYTL3 exhibits high activity but low expression in both early developmental human cortex and human embryonic stem cell (hESC)-derived neurons. Knockout of SYTL3 (SYTL3-KO) in human neurons or knockdown of Sytl3 in embryonic mouse cortex markedly promotes neuronal migration. SYTL3-KO causes an abnormal distribution of deep-layer neurons in brain organoids and reduces presynaptic neurotransmitter release in hESC-derived neurons. We further demonstrate that SYTL3-KO-accelerated neuronal migration is modulated by high expression of matrix metalloproteinases. Together, based on bioinformatics and biological experiments, we identify SYTL3 as a regulator of cortical neuronal migration in human and mouse developing brains.

Tumor necrosis factor α, protein gene product 9.5, matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 presence in congenital intra-abdominal adhesions in children under one year of age

INTRODUCTION

The regulatory role of cytokines and extracellular matrix remodeling factors in congenital intra-abdominal adhesions has not yet been defined. The aim of this study was to assess the presence and relative distribution of tumor necrosis factor α (TNF-α), protein gene product 9.5 (PGP 9.5), matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) in adhesions.

MATERIAL AND METHODS

TNF-α, PGP 9.5, MMP-2 and TIMP-2 were detected using immunohistochemical methods and their relative distribution was evaluated by means of the semiquantitative counting method. The results were analyzed using non-parametric statistical methods.

RESULTS

A moderate number of TNF-α positive macrophages and fibroblasts was found. A positive correlation was observed between the immunoreactive structures for TNF-α and PGP 9.5. A positive reaction for PGP 9.5 was observed in nerve fibers and shape modified fibroblasts. In control group tissues, positive structures were seen in significantly higher counts for PGP 9.5. Few to moderate numbers of MMP-2 positive macrophages, epithelioid cells, fibroblasts and endotheliocytes were detected. There was no significant difference between the groups. A positive reaction for TIMP-2 was seen in fibroblasts, macrophages and endotheliocytes. In control group tissues, positive structures were found in significantly higher counts for TIMP-2.

CONCLUSIONS

The positive correlation between the immunoreactive structures for TNF-α and PGP 9.5 suggests that nerve in-growth into intraabdominal adhesions might be induced by TNF-α and PGP 9.5 could have a role in maintaining inflammation. The down-regulation of PGP 9.5 suggests that pathogenesis of congenital intraabdominal adhesions may be related to hypoxia induced damage. The imbalance between MMP-2 and TIMP-2 may prove tissue fibrosis as a response to congenital peritoneal adhesions.

miR-129-3p Targeting of MCU Protects Against Glucose Fluctuation-Mediated Neuronal Damage via a Mitochondrial-Dependent Intrinsic Apoptotic Pathway

INTRODUCTION

Glucose fluctuations have an adverse effect on several diabetes-related complications, especially for the nervous system, but the underlying mechanisms are not clear. MicroRNAs are critical regulators of posttranscription in many physiological processes, such as apoptosis. Our study clarified the neuroprotective effects of miR-129-3p targeting mitochondrial calcium uniporter (MCU) in glucose fluctuation-mediated neuronal damage and the specific mechanisms involved.

METHODS

The expression of MCU and miR-129-3p was examined by real-time PCR and Western blot in the glucose fluctuation cell model. Dual-luciferase reporter assay was performed to confirm the transcriptional regulation of miR-129-3p by MCU. Fluorescent probe and assay kit assay was used to determine oxidative stress condition. Mitochondrial-dependent intrinsic apoptotic factors were examined by flow cytometry assay, enzyme-linked immunosorbent assay (ELISA), and gene and protein expression assays.

RESULTS

We found an upregulation of MCU and downregulation of miR-129-3p in glucose fluctuation-treated primary hippocampal neuronal cells, and miR-129-3p directly targeted MCU. miR-129-3p overexpression produced a dramatic reduction in calcium overload, reactive oxygen species (ROS) generation, GSH-to-GSSG ratio, MMP-2 expression in the mitochondrial-dependent intrinsic apoptosis pathway and an increase in MnSOD activity. Increasing MCU expression rescued the effects of miR-129-3p overexpression. miR-129-3p downregulation produced a significant increase in calcium overload, reactive oxygen species (ROS) generation, MMP-2 expression, cytochrome c release and cell apoptosis, and antioxidant N-acetyl cysteine (NAC) rescued the effects of miR-129-3p downregulation.

CONCLUSION

Therefore, miR-129-3p suppressed glucose fluctuation-mediated neuronal damage by targeting MCU via a mitochondrial-dependent intrinsic apoptotic pathway. The miR-129-3p/MCU axis may be a promising therapeutic target for glucose fluctuation-mediated neuronal damage.

Changes in Gene and Protein Expression of Metalloproteinase-2 and -9 and Their Inhibitors TIMP2 and TIMP3 in Different Parts of Fluoride-Exposed Rat Brain

Fluoride (F) exposure decreases brain receptor activity and neurotransmitter production. A recent study has shown that chronic fluoride exposure during childhood can affect cognitive function and decrease intelligence quotient, but the mechanism of this phenomenon is still incomplete. Extracellular matrix (ECM) and its enzymes are one of the key players of neuroplasticity which is essential for cognitive function development. Changes in the structure and the functioning of synapses are caused, among others, by ECM enzymes. These enzymes, especially matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), are involved in both physiological processes, such as learning or memory, and pathological processes like glia scare formation, brain tissue regeneration, brain-blood barrier damage and inflammation. Therefore, in this study, we examined the changes in gene and protein expression of MMP2, MMP9, TIMP2 and TIMP3 in the prefrontal cortex, hippocampus, striatum and cerebellum of rats (Wistar) exposed to relatively low F doses (50 mg/L in drinking water) during the pre- and neonatal period. We found that exposure to F during pre- and postnatal period causes a change in the mRNA and protein level of MMP2, MMP9, TIMP2 and TIMP3 in the prefrontal cortex, striatum, hippocampus and cerebellum. These changes may be associated with many disorders that are observed during F intoxication. MMPs/TIMPs imbalance may contribute to cognitive impairments. Moreover, our results suggest that a chronic inflammatory process and blood-brain barrier (BBB) damage occur in rats’ brains exposed to F.

The Morphopathogenetic Aspects of Intraabdominal Adhesions in Children under One Year of Age

Background and Objectives: The morphopathogenesis of adhesions is a complex process, characterized by the accumulation of an extracellular matrix, inflammation and hypoxia. The regulatory role between morphopathogenic factors in adhesions has not yet been defined. The aim was to investigate the appearance of transforming growth factor beta (TGFβ), basic fibroblast growth factor (FGF-2), fibroblast growth factor receptor 1 (FGFR1), protein gene product 9.5 (PGP 9.5), chromogranin A (CgA), interleukin-1 alpha (IL-1α), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-7 (IL-7), interleukin-8 (IL-8), interleukin-10 (IL-10), tumor necrosis factor alpha (TNFα), matrix metaloproteinase-2 (MMP-2) and matrix metaloproteinase-2 tissue inhibitor (TIMP-2) in intraabdominal adhesions. Materials and Methods: The study material was obtained from 49 patients under one year of age with total or partial bowel obstruction. All factors were detected using immunohistochemistry methods and their relative distribution was evaluated by means of the semiquantitative counting method. Results: Intraabdominal adhesions are characterized by increased TGFβ, FGFR1 and decreased FGF-2, PGP 9.5, IL-1, IL-4, IL-8, TIMP-2 findings. The most significant changes observed were the remodulation of the extracellular matrix, promotion of neoangiogenesis and the maintenance of a prolonged inflammation. Conclusions: The increase in TGFβ, as well as the disbalance between MMP-2 and TIMP-2 proves an increased fibrosis in intraabdominal adhesions. Less detected FGF-2 and more prominent FGR1 findings points out a compensatory receptor stimulation in response to the lacking same factor. The decrease in PGP 9.5 indicate hypoxic injury and proves the stimulation of neoangiogenesis. An unpronounced IL-1 and marked IL-10 finding indicate the local tissue protection reaction, the decrease in IL-4 could be the direct cause of giant cells, but the decrease of IL-8 could confirm a delayed chemotaxis of inflammatory cells.

Matrix Metalloproteinase 9 and Osteopontin Interact to Support Synaptogenesis in the Olfactory Bulb after Mild Traumatic Brain Injury

Olfactory receptor axons reinnervate the olfactory bulb (OB) after chemical or transection lesion. Diffuse brain injury damages the same axons, but the time course and regulators of OB reinnervation are unknown. Gelatinases (matrix metalloproteinase [MMP]2, MMP9) and their substrate osteopontin (OPN) are candidate mediators of synaptogenesis after central nervous system (CNS) insult, including olfactory axon damage. Here, we examined the time course of MMP9, OPN, and OPN receptor CD44 response to diffuse OB injury. FVBV/NJ mice received mild midline fluid percussion insult (mFPI), after which MMP9 activity and both OPN and CD44 protein expression were measured. Diffuse mFPI induced time-dependent increase in OB MMP9 activity and elevated the cell signaling 48-kD OPN fragment. This response was bimodal at 1 and 7 days post-injury. MMP9 activity was also correlated with 7-day reduction in a second 32-kD OPN peptide. CD44 increase peaked at 3 days, delayed relative to MMP9/OPN response. MMP9 and OPN immunohistochemistry suggested that deafferented tufted and mitral neurons were the principal sites for these molecular interactions. Analysis of injured MMP9 knockout (KO) mice showed that 48-kD OPN production was dependent on OB MMP9 activity, but with no KO effect on CD44 induction. Olfactory marker protein (OMP), used to identify injured olfactory axons, revealed persistent axon damage in the absence of MMP9. MMP9 KO ultrastructure at 21 days post-injury indicated that persistent OMP reduction was paired with delayed removal of degenerated axons. These results provide evidence that diffuse, concussive brain trauma induces a post-injury interaction between MMP9, OPN, and CD44, which mediates synaptic plasticity and reinnervation within the OB.

A single low dose of hydrocortisone enhances cognitive functioning in HIV-infected women

OBJECTIVE

Low-dose hydrocortisone (LDH) enhances aspects of learning and memory in select populations including patients with posttraumatic stress disorder and HIV-infected men. HIV-infected women show impairments in learning and memory, but the cognitive effects of LDH in HIV-infected women are unknown.

DESIGN

Double-blind, placebo-controlled, cross-over study examining the time-dependent effects of a single low-dose administration of hydrocortisone (10 mg oral) on cognition in 36 HIV-infected women. Participants were first randomized to LDH or placebo and then received the opposite treatment one month later.

METHODS

Cognitive performance was assessed 30 min and 4 h after pill administration to assess, respectively, nongenomic and genomic effects. Self-reported stress/anxiety and salivary cortisol were assessed throughout sessions.

RESULTS

LDH significantly increased salivary cortisol levels versus placebo; levels returned to baseline 4-h postadministration. At the 30-min assessment, LDH enhanced verbal learning and delayed memory, working memory, behavioral inhibition, and visuospatial abilities. At the 4-h assessment, LDH enhanced verbal learning and delayed memory compared with placebo. LDH-induced cognitive benefits related to reductions in cytokines and to a lesser extent to increases in cortisol.

CONCLUSION

The extended benefits from 30 min to 4 h of a single administration of LDH on learning and delayed memory suggest that targeting the hypothalamic-pituitary-adrenal axis may have potential clinical utility in HIV-infected women. These findings contrast with our findings in HIV-infected men who showed improved learning only at the 30-min assessment. Larger, longer term studies are underway to verify possible cognitive enhancing effects of LDH and the clinical significance of these effects in HIV.