The gelatinases, MMP-2 and MMP-9, as fine tuners of neuroinflammatory processes

Methamphetamine induces transcriptional changes in cultured HIV-infected mature monocytes that may contribute to HIV neuropathogenesis

HIV-associated neurocognitive impairment (HIV-NCI) persists in 15-40% of people with HIV (PWH) despite effective antiretroviral therapy. HIV-NCI significantly impacts quality of life, and there is currently no effective treatment for it. The development of HIV-NCI is complex and is mediated, in part, by the entry of HIV-infected mature monocytes into the central nervous system (CNS). Once in the CNS, these cells release inflammatory mediators that lead to neuroinflammation, and subsequent neuronal damage. Infected monocytes may infect other CNS cells as well as differentiate into macrophages, thus contributing to viral reservoirs and chronic neuroinflammation. Substance use disorders in PWH, including the use of methamphetamine (meth), can exacerbate HIV neuropathogenesis. We characterized the effects of meth on the transcriptional profile of HIV-infected mature monocytes using RNA-sequencing. We found that meth mediated an upregulation of gene transcripts related to viral infection, cell adhesion, cytoskeletal arrangement, and extracellular matrix remodeling. We also identified downregulation of several gene transcripts involved in pathogen recognition, antigen presentation, and oxidative phosphorylation pathways. These transcriptomic changes suggest that meth increases the infiltration of mature monocytes that have a migratory phenotype into the CNS, contributing to dysregulated inflammatory responses and viral reservoir establishment and persistence, both of which contribute to neuronal damage. Overall, our results highlight potential molecules that may be targeted for therapy to limit the effects of meth on HIV neuropathogenesis.

Liquid Biopsy-Based Biomarkers of Inflammatory Nociception Identified in Male Rats

Physicians are challenged in treating pain patients due to the lack of quantifiable, objective methods of measuring pain in the clinic; pain sensation is multifaceted and subjective to each individual. There is a critical need for point-of-care quantification of accessible biomarkers to provide objective analyses beyond the subjective pain scales currently employed in clinical care settings. In the present study, we employed an animal model to test the hypothesis that circulating regulators of the inflammatory response directly associate with an objective behavioral response to inflammatory pain. Upon induction of localized paw inflammation, we measured the systemic protein expression of cytokines, and activity levels of matrix metalloproteinases (MMPs) that are known to participate in the inflammatory response at the site of injury and investigated their relationship to the behavioral response across a 24 h period. Intraplantar injection with 1% λ-carrageenan induced a significant increase in paw thickness across this timespan with maximal effects observed at the 8 h timepoint when locomotor activity was also impaired. Expression of the chemokines C-X-C motif chemokine ligand 1 (CXCL1) and C-C motif chemokine ligand 2 (CCL2) positively correlated with paw inflammation and negatively correlated with locomotor activity at 8 h. The ratio of MMP9 to MMP2 activity negatively correlated with paw inflammation at the 8 h timepoint. We postulate that the CXCL1 and CCL2 as well as the ratio of MMP9 to MMP2 activity may serve as predictive biomarkers for the timecourse of inflammation-associated locomotor impairment. These data define opportunities for the future development of a point-of-care device to objectively quantify biomarkers for inflammatory pain states.

The Putative Role of Astaxanthin in Neuroinflammation Modulation: Mechanisms and Therapeutic Potential

Neuroinflammation is a protective mechanism against insults from exogenous pathogens and endogenous cellular debris and is essential for reestablishing homeostasis in the brain. However, excessive prolonged neuroinflammation inevitably leads to lesions and disease. The use of natural compounds targeting pathways involved in neuroinflammation remains a promising strategy for treating different neurological and neurodegenerative diseases. Astaxanthin, a natural xanthophyll carotenoid, is a well known antioxidant. Mounting evidence has revealed that astaxanthin is neuroprotective and has therapeutic potential by inhibiting neuroinflammation, however, its functional roles and underlying mechanisms in modulating neuroinflammation have not been systematically summarized. Hence, this review summarizes recent progress in this field and provides an update on the medical value of astaxanthin. Astaxanthin modulates neuroinflammation by alleviating oxidative stress, reducing the production of neuroinflammatory factors, inhibiting peripheral inflammation and maintaining the integrity of the blood-brain barrier. Mechanistically, astaxanthin scavenges radicals, triggers the Nrf2-induced activation of the antioxidant system, and suppresses the activation of the NF-κB and mitogen-activated protein kinase pathways. With its good biosafety and high bioavailability, astaxanthin has strong potential for modulating neuroinflammation, although some outstanding issues still require further investigation.

A Glitch in the Matrix: The Role of Extracellular Matrix Remodeling in Opioid Use Disorder

Opioid use disorder (OUD) and deaths from drug overdoses have reached unprecedented levels. Given the enormous impact of the opioid crisis on public health, a more thorough, in-depth understanding of the consequences of opioids on the brain is required to develop novel interventions and pharmacological therapeutics. In the brain, the effects of opioids are far reaching, from genes to cells, synapses, circuits, and ultimately behavior. Accumulating evidence implicates a primary role for the extracellular matrix (ECM) in opioid-induced plasticity of synapses and circuits, and the development of dependence and addiction to opioids. As a network of proteins and polysaccharides, including cell adhesion molecules, proteases, and perineuronal nets, the ECM is intimately involved in both the formation and structural support of synapses. In the human brain, recent findings support an association between altered ECM signaling and OUD, particularly within the cortical and striatal circuits involved in cognition, reward, and craving. Furthermore, the ECM signaling proteins, including matrix metalloproteinases and proteoglycans, are directly involved in opioid seeking, craving, and relapse behaviors in rodent opioid models. Both the impact of opioids on the ECM and the role of ECM signaling proteins in opioid use disorder, may, in part, depend on biological sex. Here, we highlight the current evidence supporting sex-specific roles for ECM signaling proteins in the brain and their associations with OUD. We emphasize knowledge gaps and future directions to further investigate the potential of the ECM as a therapeutic target for the treatment of OUD.

RNA Binding Motif Protein 3 Promotes Cell Metastasis and Epithelial–Mesenchymal Transition Through STAT3 Signaling Pathway in Hepatocellular Carcinoma

Purpose

RNA binding motif protein 3 (RBM3) has been reported to be dysregulated in various cancers and associated with tumor aggressiveness. Epithelial–mesenchymal transition (EMT) is an important biological process by which tumor cells acquire metastatic abilities. This study aimed to explore the regulatory and molecular mechanisms of RBM3 in EMT process.

Methods

Western blotting, IHC, and qRT-PCR were performed to evaluate the expression of target genes. Transwell assay was used to investigate the migration and invasion. RNA immunoprecipitation and luciferase reporter assay were performed to explore the correlation of RBM3 with STAT3 or microRNA-383. Animal HCC models were used to explore the role of RBM3 in metastasis in vivo.

Results

RBM3 was highly expressed in HCC tissues compared to healthy tissues, and its level was negatively correlated with the prognosis of HCC patients. RBM3 overexpression accelerated migration and invasion, promoted EMT process, and activated STAT3 signaling. EMT induced by RBM3 was not only attenuated by inhibiting pSTAT3 via S3I-201 but also abolished by suppressing STAT3 expression via siRNAs. Mechanistically, RBM3 increased STAT3 expression by stabilizing STAT3 mRNA via binding to its mRNA. As an upstream target of RBM3, microRNA-383 inhibited RBM3 expression by binding to its 3ʹUTR and resulted in the inhibition of the EMT process. Inhibition of RBM3 in HCC animal models prolonged survival and ameliorated malignant phenotypes in mice.

Conclusion

Our findings support that RBM3 promotes HCC metastasis by activating STAT3 signaling.

Uncommon Noninvasive Biomarkers for the Evaluation and Monitoring of the Etiopathogenesis of Alzheimer's Disease

Background:

Alzheimer´s disease (AD) is the most widespread dementia in the world, followed by vascular dementia. Since AD is a heterogeneous disease that shows several varied phenotypes, it is not easy to make an accurate diagnosis, so it arises when the symptoms are clear and the disease is already very advanced. Therefore, it is important to find out biomarkers for AD early diagnosis that facilitate treatment or slow down the disease. Classic biomarkers are obtained from cerebrospinal fluid and plasma, along with brain imaging by positron emission tomography. Attempts have been made to discover uncommon biomarkers from other body fluids, which are addressed in this update.

Objective:

This update aims to describe recent biomarkers from minimally invasive body fluids for the patients, such as saliva, urine, eye fluid or tears.

Methods:

Biomarkers were determined in patients versus controls by single tandem mass spectrometry, and immunoassays. Metabolites were identified by nuclear magnetic resonance, and microRNAs with genome-wide high-throughput real-time polymerase chain reaction-based platforms.

Results:

Biomarkers from urine, saliva, and eye fluid were described, including peptides/proteins, metabolites, and some microRNAs. The association with AD neuroinflammation and neurodegeneration was analyzed, highlighting the contribution of matrix metalloproteinases, the immune system and microglia, as well as the vascular system.

Conclusion:

Unusual biomarkers have been developed, which distinguish each stage and progression of the disease, and are suitable for the early AD diagnosis. An outstanding relationship of biomarkers with neuroinflammation and neurodegeneration was assessed, clearing up concerns of the etiopathogenesis of AD.

Chemical Design of Activatable Photoacoustic Probes for Precise Biomedical Applications

Photoacoustic (PA) imaging technology, a three-dimensional hybrid imaging modality that integrates the advantage of optical and acoustic imaging, has great application prospects in molecular imaging due to its high imaging depth and resolution. To endow PA imaging with the ability for real-time molecular visualization and precise biomedical diagnosis, numerous activatable molecular PA probes which can specifically alter their PA intensities upon reacting with the targets or biological events of interest have been developed. This review highlights the recent developments of activatable PA probes for precise biomedical applications including molecular detection of the biotargets and imaging of the biological events. First, the generation mechanism of PA signals will be given, followed by a brief introduction to contrast agents used for PA probe design. Then we will particularly summarize the general design principles for the alteration of PA signals and activatable strategies for developing precise PA probes. Furthermore, we will give a detailed discussion of activatable PA probes in molecular detection and biomedical imaging applications in living systems. At last, the current challenges and outlooks of future PA probes will be discussed. We hope that this review will stimulate new ideas to explore the potentials of activatable PA probes for precise biomedical applications in the future.

Correlation Between Blood Glucose Variability and Early Therapeutic Effects After Intravenous Thrombolysis With Alteplase and Levels of Serum Inflammatory Factors in Patients With Acute Ischemic Stroke

Objective

To investigate the effects of blood glucose variability on early therapeutic effects after intravenous thrombolysis with alteplase and the levels of serum inflammatory factors in patients with acute ischemic stroke (AIS).

Methods

We enrolled AIS patients who received intravenous thrombolysis within 4.5 h of the onset of symptoms. Clinical data, including the National Institutes of Health Stroke Scale (NIHSS), glycosylated hemoglobin, mean blood glucose, standard deviation of blood glucose, mean amplitude of glycemic excursion, mean variation coefficient of blood glucose, interleukin-6 (IL-6), active matrix metalloproteinase-9 (MMP-9), tumor necrosis factor α (TNF-α), and hypersensitive C-reactive protein (hs-CRP) levels, were compared between a group who showed improvement (the improvement group) and a group who did not show improvement (the non-improvement group). Relevant factors for early neurological improvement after thrombolysis with alteplase were analyzed by using multivariate logistic regression models. A Pearson linear correlation analysis was also performed on blood glucose variation and inflammatory factor levels within the two groups.

Results

A total of 146 patients were included, 63 of which had early symptom improvement (43.15%). The diabetes ratio, atrial fibrillation ratio, baseline NHISS score, random blood glucose at admission, and glycosylated hemoglobin of patients in the improvement group were significantly lower than those in the non-improvement group (P < 0.05 in all cases). The mean blood glucose, standard deviation of blood glucose, mean amplitude of glycemic excursion, and mean blood glucose variation coefficients of patients in the improvement group were significantly lower than those in the non-improvement group (P < 0.05). Serum inflammatory factor levels, including IL-6, MMP-9, TNF-α and hs-CRP, were significantly lower in patients in the improvement group compared to patients in the non-improvement group (P < 0.05). Multivariate logistic regression analysis showed that baseline NIHSS scores (OR = 1.28, 95% CI = 1.05-1.62, P = 0.02), glycosylated hemoglobin scores (OR = 2.57, 95% CI = 1.78-3.98, P = 0.0005), diabetes (OR = 13.10, 95% CI = 1.63~131.45, P = 0.021), the mean amplitude of glycemic excursion (OR = 2.98, 95% CI = 1.92-5.00, P < 0.0001), and the mean variation coefficient of blood glucose (OR = 1.40, 95% CI = 1.26-1.60, P = 0.0078) were significantly correlated with early symptom improvement after thrombolysis. Pearson linear correlation analysis showed that the standard deviation of blood glucose, mean amplitude of glycemic excursion, and the mean variation coefficient of blood glucose were significantly positively correlated with IL-6, MMP-9, TNF-α and hs-CRP levels (P < 0.01).

Conclusions

Blood glucose variability is correlated with early neurological improvement after intravenous thrombolysis with alteplase in AIS patients. With the increase of blood glucose fluctuation range, the inflammatory response is enhanced, which affects the prognosis of patients.

Brain Barriers and Multiple Sclerosis: Novel Treatment Approaches from a Brain Barriers Perspective

Multiple sclerosis (MS) is considered a prototypic organ specific autoimmune disease targeting the central nervous system (CNS). Blood-brain barrier (BBB) breakdown and enhanced immune cell infiltration into the CNS parenchyma are early hallmarks of CNS lesion formation. Therapeutic targeting of immune cell trafficking across the BBB has proven a successful therapy for the treatment of MS, but comes with side effects and is no longer effective once patients have entered the progressive phase of the disease. Beyond the endothelial BBB, epithelial and glial brain barriers establish compartments in the CNS that differ in their accessibility to the immune system. There is increasing evidence that brain barrier abnormalities persist during the progressive stages of MS. Here, we summarize the role of endothelial, epithelial, and glial brain barriers in maintaining CNS immune privilege and our current knowledge on how impairment of these barriers contributes to MS pathogenesis. We discuss how therapeutic stabilization of brain barriers integrity may improve the safety of current therapeutic regimes for treating MS. This may also allow for the development of entirely novel therapeutic approaches aiming to restore brain barriers integrity and thus CNS homeostasis, which may be specifically beneficial for the treatment of progressive MS.

Zanthoxylum bungeanum Seed Oil Attenuates LPS-Induced BEAS-2B Cell Activation and Inflammation by Inhibiting the TLR4/MyD88/NF-κB Signaling Pathway

Background

Zanthoxylum bungeanum seed oil (ZBSO) is a natural essential oil derived from the seeds of the Chinese medicinal plant Zanthoxylum bungeanum, which has been investigated for antitumor and anti-inflammatory effects. However, little is known regarding the effects of ZBSO in chronic obstructive pulmonary disease (COPD).

Methods

In this study, lung epithelial cells (BEAS-2B) were induced by lipopolysaccharide (LPS) to establish an in vitro model of COPD, and cytotoxicity was detected by a cell counting kit 8 (CCK-8) assay. Griess test, enzyme-linked immunosorbent assay (ELISA), reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), western blot, immunofluorescence, and molecular docking analyses were used to investigate the effects of ZBSO and its potential mechanisms.

Results

The results showed that LPS promoted the expression of nitric oxide (NO), reactive oxygen species (ROS), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinase-2 (MMP-2), MMP-9, cyclooxygenase-2 (COX-2), and prostaglandin E₂ (PGE2), suggesting that LPS can induce inflammation and oxidative stress in BEAS-2B cells. ZBSO inhibits the LPS-induced expression of inflammatory mediators and proinflammatory cytokines in BEAS-2B cells. The molecular docking results indicated that active components in ZBSO could successfully dock with toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and p65. Immunofluorescence and western blot analyses further demonstrated that ZBSO repressed protein expression associated with the TLR4/MyD88/nuclear factor-κB (NF-κB) signaling pathway.

Conclusions

ZBSO reduced the inflammatory response and oxidative stress induced by LPS by inhibiting the TLR4/MyD88/NF-κB signaling pathway, thereby suppressing COPD. ZBSO may represent a promising therapeutic candidate for COPD treatment.

Freshly Thawed Cryobanked Human Neural Stem Cells Engraft within Endogenous Neurogenic Niches and Restore Cognitive Function after Chronic Traumatic Brain Injury

Human neural stem cells (hNSCs) have potential as a cell therapy after traumatic brain injury (TBI). While various studies have demonstrated the efficacy of NSCs from ongoing culture, there is a significant gap in our understanding of freshly thawed cells from cryobanked stocks-a more clinically relevant source. To address these shortfalls, the therapeutic potential of our previously validated Shef-6.0 human embryonic stem cell (hESC)-derived hNSC line was tested after long-term cryostorage and thawing before transplant. Immunodeficient athymic nude rats received a moderate unilateral controlled cortical impact (CCI) injury. At four weeks post-injury, 6 × 105 freshly thawed hNSCs were transplanted into six injection sites (two ipsi- and four contra-lateral) with 53.4% of cells surviving three months post-transplant. Interestingly, most hNSCs were engrafted in the meninges and the lining of lateral ventricles, associated with high CXCR4 expression and a chemotactic response to SDF1alpha (CXCL12). While some expressed markers of neuron, astrocyte, and oligodendrocyte lineages, the majority remained progenitors, identified through doublecortin expression (78.1%). Importantly, transplantation resulted in improved spatial learning and memory in Morris water maze navigation and reduced risk taking in an elevated plus maze. Investigating potential mechanisms of action, we identified an increase in ipsilateral host hippocampus cornu ammonis (CA) neuron survival, contralateral dentate gyrus (DG) volume, and DG neural progenitor morphology as well as a reduction in neuroinflammation. Together, these findings validate the potential of hNSCs to improve function after TBI and demonstrate that long-term biobanking of cells and thawing aliquots before use may be suitable for clinical deployment.

Local and Systemic Expression Pattern of MMP-2 and MMP-9 in Complex Regional Pain Syndrome

Matrix metalloproteinases (MMP)-2 and MMP-9 play important roles in inflammation as well as in pain processes. For this reason, we compared the concentrations of these enzymes in skin and serum of patients with complex regional pain syndrome (CRPS), other pain diseases and healthy subjects. We analyzed ipsi- and contralateral skin biopsies of 18 CRPS patients, as well as in 10 pain controls and 9 healthy subjects. Serum samples were analyzed from 20 CRPS, 17 pain controls and 17 healthy subjects. All samples were analyzed with ELISA. Concentrations were then compared to clinical data as well as to quantitative sensory testing data.MMP-2 was increased in both ipsi- and contralateral skin biopsies of CRPS patients compared to healthy subjects. While low ipsilateral MMP-2 was associated with trophic changes, contralateral MMP-2 inversely correlated with the CRPS severity. MMP-9 was also locally increased in ipsilateral CRPS skin, and higher ipsi- and contralateral MMP-9 levels correlated with CRPS severity. We conclude that MMP-2 and MMP-9 are differently expressed depending on the clinical phenotype in CRPS. PERSPECTIVE: This article describes an upregulation of MMPs in CRPS and pain controls and shows different expression of MMP-2 and -9 depending on clinical phenotype in CRPS. These results provide evidence that MMP-2 and -9 play a key role in CRPS pathophysiology.

Glibenclamide Attenuates Neuroinflammation and Promotes Neurological Recovery After Intracerebral Hemorrhage in Aged Rats

Intracerebral hemorrhage (ICH) is a common disease in the elderly population. Inflammation following ICH plays a detrimental role in secondary brain injury, which is associated with a poor prognosis of patients with ICH, and no efficient pharmacological preventions are available. Here, we investigated the effects of glibenclamide (GLC) on neuroinflammation in an autoblood-induced aged rat (18 months old) model of ICH. Rats were randomized into the sham, vehicle, and GLC groups. First, we investigated the expression level of sulfonylurea receptor 1 (Sur1) surrounding the hematoma after ICH. Then, neurological scores were calculated, and water maze tests, brain water content analysis, western blotting, and immunofluorescence assays were implemented to detect the neuroprotective effect of GLC. The expression of the Sur1-Trpm4 channel was significantly increased in the perihematomal tissue following ICH in aged rats. The GLC administration effectively reduced brain edema and improved neurofunction deficits following ICH. In addition, GLC increased the expression of brain-derived neurotrophic factors and decreased the expression of proinflammatory factors [tumor necrosis factor (TNF)-α,interleukin (IL)-1, and IL-6]. Moreover, GLC markedly reduced Ikappa-B (IκB) kinase (IKK) expression in microglia and nuclear factor (NF)-κB-P65 levels in perihematomal tissue. GLC ameliorated ICH-induced neuroinflammation and improved neurological outcomes in aged rats. In part, GLC may exert these effects by regulating the NF-κB signaling pathway through the Sur1-Trpm4 channel.

Role of matrix metalloproteinases and their tissue inhibitors in the pathological mechanisms underlying maxillofacial cystic lesions

Cystic lesions are considered to be one of the most common pathologies of the maxillofacial region, and matrix metalloproteinases (MMPs) may represent potential etiological factors. The aim of the present study was to elucidate the role of MMP-2 and MMP-9, and their endogenous tissue inhibitors, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2, respectively, in the pathogenesis of maxillofacial cystic lesions. A total of 25 patients diagnosed with radicular cysts (RCs; n=20), dentigerous cysts (n=3) and retention cysts (RtCs; n=7) were enrolled in the present study. Gelatin zymography was performed to assess the gelatinolytic activity of MMP-2 and MMP-9, and commercial ELISA kits were used to determine TIMP-1 and TIMP-2 concentrations. Gelatin zymography revealed the presence of both MMP-2 and MMP-9 in all types of samples analyzed. An increase in MMP-9 activity, TIMP-1 concentration and MMP-9/TIMP-1 ratio was observed in the fluid obtained from RCs compared with that obtained from RtCs. In conclusion, MMP-9 may be involved in the pathogenesis of RCs, whereas the activity of MMP-2 in the wall of RtCs was low, and this gelatinase did not appear to significantly affect the development of this type of lesion.

Deficiency in MT5-MMP Supports Branching of Human iPSCs-Derived Neurons and Reduces Expression of GLAST/S100 in iPSCs-Derived Astrocytes

For some time, it has been accepted that the β-site APP cleaving enzyme 1 (BACE1) and the γ-secretase are two main players in the amyloidogenic processing of the β-amyloid precursor protein (APP). Recently, the membrane-type 5 matrix metalloproteinase (MT5-MMP/MMP-24), mainly expressed in the nervous system, has been highlighted as a new key player in APP-processing, able to stimulate amyloidogenesis and also to generate a neurotoxic APP derivative. In addition, the loss of MT5-MMP has been demonstrated to abrogate pathological hallmarks in a mouse model of Alzheimer’s disease (AD), thus shedding light on MT5-MMP as an attractive new therapeutic target. However, a more comprehensive analysis of the role of MT5-MMP is necessary to evaluate how its targeting affects neurons and glia in pathological and physiological situations. In this study, leveraging on CRISPR-Cas9 genome editing strategy, we established cultures of human-induced pluripotent stem cells (hiPSC)-derived neurons and astrocytes to investigate the impact of MT5-MMP deficiency on their phenotypes. We found that MT5-MMP-deficient neurons exhibited an increased number of primary and secondary neurites, as compared to isogenic hiPSC-derived neurons. Moreover, MT5-MMP-deficient astrocytes displayed higher surface area and volume compared to control astrocytes. The MT5-MMP-deficient astrocytes also exhibited decreased GLAST and S100β expression. These findings provide novel insights into the physiological role of MT5-MMP in human neurons and astrocytes, suggesting that therapeutic strategies targeting MT5-MMP should be controlled for potential side effects on astrocytic physiology and neuronal morphology.

A Metalloproteinase Induces an Inflammatory Response in Preadipocytes with the Activation of COX Signalling Pathways and Participation of Endogenous Phospholipases A2

Matrix metalloproteinases (MMPs) are proteolytic enzymes that have been associated with the pathogenesis of inflammatory diseases and obesity. Adipose tissue in turn is an active endocrine organ capable of secreting a range of proinflammatory mediators with autocrine and paracrine properties, which contribute to the inflammation of adipose tissue and adjacent tissues. However, the potential inflammatory effects of MMPs in adipose tissue cells are still unknown. This study investigates the effects of BmooMPα-I, a single-domain snake venom metalloproteinase (SVMP), in activating an inflammatory response by 3T3-L1 preadipocytes in culture, focusing on prostaglandins (PGs), cytokines, and adipocytokines biosynthesis and mechanisms involved in prostaglandin E2 (PGE2) release. The results show that BmooMPα-I induced the release of PGE2, prostaglandin I2 (PGI2), monocyte chemoattractant protein-1 (MCP-1), and adiponectin by preadipocytes. BmooMPα-I-induced PGE2 biosynthesis was dependent on group-IIA-secreted phospholipase A2 (sPLA2-IIA), cytosolic phospholipase A2-α (cPLA2-α), and cyclooxygenase (COX)-1 and -2 pathways. Moreover, BmooMPα-I upregulated COX-2 protein expression but not microsomal prostaglandin E synthase-1 (mPGES-1) expression. In addition, we demonstrate that the enzymatic activity of BmooMPα-I is essential for the activation of prostanoid synthesis pathways in preadipocytes. These data highlight preadipocytes as important targets for metalloproteinases and provide new insights into the contribution of these enzymes to the inflammation of adipose tissue and tissues adjacent to it.

Mild blast wave exposure produces intensity-dependent changes in MMP2 expression patches in rat brains - Findings from different blast severities

Matrix metalloproteinase 2 (MMP2) is a gelatinase with multiple functions at the neurovascular interface, including local modification of the glia limitans to facilitate access of immune cells into the brain and amyloid-beta degradation during responses to injury or disease. This study examines regional changes in immunoreactive MMP2 in the rat brain after a single mild (2.7-7.9 psi peak) or moderate (13-17.5 psi peak) blast overpressure (BOP) exposure. Immunopositive MMP2 expression was examined quantitatively in histological sections of decalcified rat heads as a marker at 2, 24, and 72 h after BOP. The MMP2 immunoreactivity was isolated to patchy deposits in brain parenchyma surrounding blood vessels. Separate analyses were conducted for the cerebellum, brain stem caudal to the thalamo-mesencephalic junction, and the cerebrum (including diencephalon). The deposits varied in number, size, staining homogeneity (standard deviation of immunopositive region), and a cumulative measure, the product of size, average intensity and number, as a function of blast intensity and time. The sequences of changes in MMP2 spots from sham control animals suggested that the mild BOP exposure differences normalized within 72 h. However, the responses to moderate exposure revealed a delayed response at 72 h in the subtentorial brain stem and the cerebrum, but not the cerebellum. Hence, local MMP2 responses may be a contextual biomarker for locally regulated responses to widely distributed brain injury foci.

Brain-Derived Neurotrophic Factor Signaling in the Pathophysiology of Alzheimer's Disease: Beneficial Effects of Flavonoids for Neuroprotection

The function of the brain-derived neurotrophic factor (BDNF) via activation through its high-affinity receptor Tropomyosin receptor kinase B (TrkB) has a pivotal role in cell differentiation, cell survival, synaptic plasticity, and both embryonic and adult neurogenesis in central nervous system neurons. A number of studies have demonstrated the possible involvement of altered expression and action of the BDNF/TrkB signaling in the pathogenesis of neurodegenerative diseases, including Alzheimer’s disease (AD). In this review, we introduce an essential role of the BDNF and its downstream signaling in neural function. We also review the current evidence on the deregulated the BDNF signaling in the pathophysiology of AD at gene, mRNA, and protein levels. Further, we discuss a potential usefulness of small compounds, including flavonoids, which can stimulate BDNF-related signaling as a BDNF-targeting therapy.

Trichinella spiralis excretory-secretory products downregulate MMP-9 in Dark Agouti rats affected by experimental autoimmune encephalomyelitis

Matrix metalloproteinases (MMPs), are implicated in the pathogenesis of multiple sclerosis (MS) and in its animal model, experimental autoimmune encephalomyelitis (EAE). Our aim was to investigate whether amelioration of EAE in Dark Agouti (DA) rats, induced by Trichinella spiralis muscle larvae excretory-secretory products (ES L1), could be related to the level and activity of gelatinases, MMP-9 and MMP-2. Serum levels of MMP-9, MMP-2, NGAL/MMP-9, TIMP-1, and cytokines, evaluated by gel-zymography or ELISA, as well as gelatinases and TIMP-1 expression in the spinal cord (SC), were determined in: i) EAE induced, ii) ES L1-treated EAE induced animals. Milder clinical signs in ES L1-treated EAE induced DA rats were accompanied with lower serum levels of MMP-9 and NGAL/MMP-9 complex. However, the correlation between the severity of EAE and the level of serum MMP-9 was found only in the peak of the disease, with MMP-9/TIMP-1 ratio higher in EAE animals without ES L1 treatment. Lower expression of MMP-9 in SC of ES L1-treated, EAE induced rats, correlated with the reduced number of SC infiltrating cells. In SC infiltrates, in the effector and the recovery phase, production of anti-inflammatory cytokines IL-4 and IL-10 was higher in animals treated with ES L1 prior to EAE induction, compared to untreated EAE animals. Reduced expression of MMP-9 in SC tissue, which correlated with the reduced number of infiltrating cells, might be ascribed to regulatory mechanisms, among which is IL-10.

DNMT3b SUMOylation Mediated MMP-2 Upregulation Contribute to Paclitaxel Induced Neuropathic Pain

Paclitaxel is a common chemotherapeutic agent in cancer treatment, while it often causes chemotherapy-induced peripheral neuropathy (CIPN), which manifested as hyperalgesia and allodynia, and its mechanism remains largely unknown. The previous study has shown that matrix metalloproteinase-2 (MMP-2) plays a pivotal role in spinal nerve ligation (SNL) induced neuropathic pain, but its function in CIPN and exact molecular mechanisms underlying upregulation is not explored. Our present study revealed that MMP-2 is also upregulated in paclitaxel induced neuropathic pain (NP), and knockdown it by siRNA can ameliorate mechanical allodynia. Since DNA methylation is closely related to gene transcription, we explored the methylation status of the MMP-2 gene and demonstrated that MMP-2 upregulation is related to the reduced methylation level of its promoter. DNA methylation is mediated by DNA methyltransferases (DNMTs), and previous studies suggested that three main types of DNMTs can undergo SUMOylation. Our next study revealed that SUMO1 modification of DNMT3b is significantly enhanced. Intrathecal administration of SUMOylation inhibitor, ginkgolic acid (GA), could reverse enhanced SUMO1 modification of DNMT3b and upregulation of MMP-2 in the model rats. Further investigation suggested that DNMT3b binding activity to the promoter region of the MMP-2 gene is significantly decreased in paclitaxel treated rats, and the administration of GA can reverse these effects, which is also accompanied by changes in the promoter methylation status of the MMP-2 gene. Our study demonstrates that MMP-2 up-regulation mediated by DNMT3b SUMOylation is essential for paclitaxel induced NP development, which brings us new therapeutic options for CIPN.

MMP24 Contributes to Neuropathic Pain in an FTO-Dependent Manner in the Spinal Cord Neurons

Nerve injury-induced gene expression change in the spinal cord is critical for neuropathic pain genesis. RNA N⁶-methyladenosine (m⁶A) modification represents an additional layer of gene regulation. We showed that spinal nerve ligation (SNL) upregulated the expression of matrix metallopeptidase 24 (MMP24) protein, but not Mmp24 mRNA, in the spinal cord neurons. Blocking the SNL-induced upregulation of spinal MMP24 attenuated local neuron sensitization, neuropathic pain development and maintenance. Conversely, mimicking MMP24 increase promoted the spinal ERK activation and produced evoked nociceptive hypersensitivity. Methylated RNA Immunoprecipitation Sequencing (MeRIP-seq) and RNA Immunoprecipitation (RIP) assay indicated the decreased m⁶A enrichment in the Mmp24 mRNA under neuropathic pain condition. Moreover, fat-mass and obesity-associated protein (FTO) was colocalized with MMP24 in spinal neurons and shown increased binding to the Mmp24 mRNA in the spinal cord after SNL. Overexpression or suppression of FTO correlates with promotion or inhibition of MMP24 expression in cultured spinal cord neurons. In conclusion, SNL promoted the m⁶A eraser FTO binding to the Mmp24 mRNA, which subsequently facilitated the translation of MMP24 in the spinal cord, and ultimately contributed to neuropathic pain genesis.

Sodium Monoiodoacetate Dose-Dependent Changes in Matrix Metalloproteinases and Inflammatory Components as Prognostic Factors for the Progression of Osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease that primarily affects people over 65 years old. During OA progression irreversible cartilage, synovial membrane and subchondral bone degradation is observed, which results in the development of difficult-to-treat chronic pain. One of the most important factors in OA progression is joint inflammation. Both proinflammatory and anti-inflammatory factors, as well as extracellular matrix degradation enzymes (matrix metalloproteinases (MMPs), play an important role in disease development. One of the most widely used animal OA models involves an intra-articular injection of sodium monoiodoacetate (MIA) directly into the joint capsule, which results in glycolysis inhibition in chondrocytes and cartilage degeneration. This model mimics the degenerative changes observed in OA patients. However, the dose of MIA varies in the literature, ranging from 0.5 to 4.8 mg. The aim of our study was to characterize grading changes after injection of 1, 2 or 3 mg of MIA at the behavioral and molecular levels over a 28-day period. In the behavioral studies, MIA injection at all doses resulted in a gradual increase in tactile allodynia and resulted in abnormal weight bearing during free walking sequences. At several days post-OA induction, cartilage, synovial membrane and synovial fluid samples were collected, and qPCR and Western blot analyses were performed. We observed significant dose- and time-dependent changes in both gene expression and protein secretion levels. Inflammatory factors (CCL2, CXCL1, IL-1β, COMP) increased at the beginning of the experiment, indicating a transient inflammatory state connected to the MIA injection and, in more severe OA, also in the advanced stages of the disease. Overall, the results in the 1 mg MIA group were not consistently clear, indicating that the lowest tested dose may not be sufficient to induce long-lasting OA-like changes at the molecular level. In the 2 mg MIA group, significant alterations in the measured factors were observed. In the 3 mg MIA group, MMP-2, MMP-3, MMP-9, and MMP-13 levels showed very strong upregulation, which may cause overly strong reactions in animals. Therefore, a dose of 2 mg appears optimal, as it induces significant but not excessive OA-like changes in a rat model.

Impact of MMP2 rs243865 and MMP3 rs3025058 Polymorphisms on Clinical Findings in Alzheimer's Disease Patients

Alzheimer's disease (AD) is a chronic neurodegenerative disease of the central nervous system with higher prevalence in elderly people. Despite numerous research studies, the etiopathogenesis of AD remains unclear. Matrix metalloproteinases (MMPs) are endopeptidases involved in the cleavage of extracellular matrix proteins and basement membrane compounds. In the brain, the pathological role of MMPs includes the disruption of the blood-brain barrier leading to the induction of neuroinflammation. Among various MMPs, MMP-2 and MMP-3 belong to candidate molecules related to AD pathology. In our study, we aimed to evaluate the association of MMP2 rs243865 and MMP3 rs3025058 polymorphisms with AD susceptibility and their influence on age at onset and MoCA score in patients from Slovakia. Both MMP gene promoter polymorphisms were genotyped in 171 AD patients and 308 controls by the PCR-RFLP method. No statistically significant differences in the distribution of MMP2 rs243865 (-1306 C>T) and MMP3 rs3025058 (-1171 5A>6A) alleles/genotypes were found between AD patients and the control group. However, correlation with clinical findings revealed later age at disease onset in MMP2 rs243865 CC carriers in the dominant model as compared to T allele carriers (CC vs. CT+TT: 78.44 ± 6.28 vs. 76.36 ± 6.39, p = 0.036). The results of MMP3 rs3025058 analysis revealed that 5A/6A carriers in the overdominant model tended to have earlier age at disease onset as compared to other MMP3 genotype carriers (5A/6A vs. 5A/5A+6A/6A: 76.61 ± 5.88 vs. 78.57 ± 6.79, p = 0.045). In conclusion, our results suggest that MMP2 rs243865 and MMP3 rs3025058 promoter polymorphisms may have influence on age at onset in AD patients.

Effects of metal nanoparticles on tight junction-associated proteins via HIF-1α/miR-29b/MMPs pathway in human epidermal keratinocytes

Background

The increasing use of metal nanoparticles in industry and biomedicine raises the risk for unintentional exposure. The ability of metal nanoparticles to penetrate the skin ranges from stopping at the stratum corneum to passing below the dermis and entering the systemic circulation. Despite the potential health risks associated with skin exposure to metal nanoparticles, the mechanisms underlying the toxicity of metal nanoparticles on skin keratinocytes remain unclear. In this study, we proposed that exposure of human epidermal keratinocytes (HaCaT) to metal nanoparticles, such as nickel nanoparticles, dysregulates tight-junction associated proteins by interacting with the HIF-1α/miR-29b/MMPs axis.

Methods

We performed dose-response and time-response studies in HaCaT cells to observe the effects of Nano-Ni or Nano-TiO₂ on the expression and activity of MMP-2 and MMP-9, and on the expression of tight junction-associated proteins, TIMP-1, TIMP-2, miR-29b, and HIF-1α. In the dose-response studies, cells were exposed to 0, 10, or 20 μg/mL of Nano-Ni or Nano-TiO₂ for 24 h. In the time-response studies, cells were exposed to 20 μg/mL of Nano-Ni for 12, 24, 48, or 72 h. After treatment, cells were collected to either assess the expression of mRNAs and miR-29b by real-time PCR or to determine the expression of tight junction-associated proteins and HIF-1α nuclear accumulation by Western blot and/or immunofluorescent staining; the conditioned media were collected to evaluate the MMP-2 and MMP-9 activities by gelatin zymography assay. To further investigate the mechanisms underlying Nano-Ni-induced dysregulation of tight junction-associated proteins, we employed a HIF-1α inhibitor, CAY10585, to perturb HIF-1α accumulation in one experiment, and transfected a miR-29b-3p mimic into the HaCaT cells before Nano-Ni exposure in another experiment. Cells and conditioned media were collected, and the expression and activities of MMPs and the expression of tight junction-associated proteins were determined as described above.

Results

Exposure of HaCaT cells to Nano-Ni resulted in a dose-dependent increase in the expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 and the activities of MMP-2 and MMP-9. However, exposure of cells to Nano-TiO₂ did not cause these effects. Nano-Ni caused a dose-dependent decrease in the expression of miR-29b and tight junction-associated proteins, such as ZO-1, occludin, and claudin-1, while Nano-TiO₂ did not. Nano-Ni also caused a dose-dependent increase in HIF-1α nuclear accumulation. The time-response studies showed that Nano-Ni caused significantly increased expressions of MMP-2 at 24 h, MMP-9 at 12, 24, and 48 h, TIMP-1 from 24 to 72 h, and TIMP-2 from 12 to 72 h post-exposure. The expression of miR-29b and tight junction-associated proteins such as ZO-1, occludin, and claudin-1 decreased as early as 12 h post-exposure, and their levels declined gradually over time. Pretreatment of cells with a HIF-1α inhibitor, CAY10585, abolished Nano-Ni-induced miR-29b down-regulation and MMP-2/9 up-regulation. Introduction of a miR-29b-3p mimic into HaCaT cells by transfection before Nano-Ni exposure ameliorated Nano-Ni-induced increased expression and activity of MMP-2 and MMP-9 and restored Nano-Ni-induced down-regulation of tight junction-associated proteins.

Conclusion

Our study herein demonstrated that exposure of human epidermal keratinocytes to Nano-Ni caused increased HIF-1α nuclear accumulation and increased transcription and activity of MMP-2 and MMP-9 and down-regulation of miR-29b and tight junction-associated proteins. Nano-Ni-induced miR-29b down-regulation was through Nano-Ni-induced HIF-1α nuclear accumulation. Restoration of miR-29b level by miR-29b-3p mimic transfection abolished Nano-Ni-induced MMP-2 and MMP-9 activation and down-regulation of tight junction-associated proteins. In summary, our results demonstrated that Nano-Ni-induced dysregulation of tight junction-associated proteins in skin keratinocytes was via HIF-1α/miR-29b/MMPs pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-021-00405-2.

Biosensing surfaces and therapeutic biomaterials for the central nervous system in COVID-19

COVID-19 can affect the central nervous system (CNS) indirectly by inflammatory mechanisms and even directly enter the CNS. Thereby, COVID-19 can evoke a range of neurosensory conditions belonging to infectious, inflammatory, demyelinating, and degenerative classes. A broad range of non-specific options, including anti-viral agents and anti-inflammatory protocols, is available with varying therapeutic. Due to the high mortality and morbidity in COVID-19-related brain damage, some changes to these general protocols, however, are necessary for ensuring the delivery of therapeutic(s) to the specific components of the CNS to meet their specific requirements. The biomaterials approach permits crossing the blood-brain barrier (BBB) and drug delivery in a more accurate and sustained manner. Beyond the BBB, drugs can protect neural cells, stimulate endogenous stem cells, and induce plasticity more effectively. Biomaterials for cell delivery exist, providing an efficient tool to improve cell retention, survival, differentiation, and integration. This paper will review the potentials of the biomaterials approach for the damaged CNS in COVID-19. It mainly includes biomaterials for promoting synaptic plasticity and modulation of inflammation in the post-stroke brain, extracellular vesicles, exosomes, and conductive biomaterials to facilitate neural regeneration, and artificial nerve conduits for treatment of neuropathies. Also, biosensing surfaces applicable to the first sensory interface between the host and the virus that encourage the generation of accelerated anti-viral immunity theoretically offer hope in solving COVID-19.

MMP9 and IGFBP1 Regulate Tumor Immune and Drive Tumor Progression in Clear Cell Renal Cell Carcinoma

Immunotherapy is a novel approach and has been used in various diseases, especially in cancers. Recently, immunotherapy has gradually been used to treat advanced clear cell renal cell carcinoma (ccRCC) or metastatic ccRCC. However, the efficacy of immunotherapy is not satisfying due to the influence of the tumor microenvironment. In this study, we mainly focused on the abundance and function of tumor-infiltrating immune cells (TIICs). Monocyte and TNM stage were identified as independent prognostic factors via CIBERSORT and Cox regression analysis. Then, ccRCC patients were divided into high risk/TNMhighMonocyteslow cluster and low risk/TNMlowMonocyteshigh cluster. Further differential gene analysis, protein-protein interaction (PPI) network, and survival analysis screened nine hub genes between the above two clusters. MMP9 and IGFBP1 were selected for further study through sample validation. Moreover, gene set enrichment analysis revealed that MMP9 and IGFBP1 were involved in tumor immune via mediating cell surface receptor signal pathway, cytokine production pathway, or monocyte signal pathway. In conclusion, these findings suggested that monocyte acted as a protective factor and MMP9/IGFBP1 played a vital role in tumor immune, which might become potential novel biomarkers and therapeutic targets for immunotherapy in ccRCC.

Integrated traditional Chinese medicine alleviates sciatica while regulating gene expression in peripheral blood

Background

Although integrated traditional Chinese medicine (TCM) has long been indicated to be effective in the treatment of sciatica and is widely used in the management of this condition, the mechanism by which integrated TCM alleviates sciatica has not yet been fully defined, and the effect of integrated TCM on gene expression in the peripheral blood of patients with sciatica is still unknown. We performed this study to investigate the effect of integrated TCM on peripheral blood gene expression in patients with sciatica and to explore new clues for studying the mechanism of integrated TCM in alleviating sciatica.

Methods

We used a microarray to identify differentially expressed genes (DEGs) in the peripheral blood of patients with sciatica and healthy controls (DEGs-baseline), bioinformatic analysis to reveal the characteristics of DEGs-baseline, and the key genes that contribute to the gene dysregulation. A microarray was also used to identify DEGs in the peripheral blood of patients with sciatica after integrated TCM treatment compared with those at baseline, and the expression levels of DEGs were validated by qRT-PCR.

Results

We identified 153 DEGs-baseline, which included 131 upregulated genes and 22 downregulated genes. Bioinformatic analysis revealed that most of the DEGs-baseline were related to immunity and the inflammatory response and that TLR4, MMP9, MPO, CAMP, RETN, TLR5, and IL1RN were key genes involved in the dysregulation of genes in the peripheral blood of patients with sciatica. The expression levels of TLR5, IL1RN, SLC8A1, RBM20, GPER1, IL27, SOCS1, and GRTP1-AS1 were decreased in the peripheral blood of patients after integrated TCM treatment compared with that at baseline, which was accompanied by relief of pain.

Conclusion

Integrated TCM treatment relieved pain while regulating the gene expression of TLR5, IL1RN, SLC8A1, RBM20, GPER1, IL27, SOCS1, and GRTP1-AS1 in the peripheral blood of patients with sciatica. Our study provides new clues for studying the mechanism of TCM in treating sciatica.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02280-1.

Microarray analysis reveals an inflammatory transcriptomic signature in peripheral blood for sciatica

BACKGROUND

Although the pathology of sciatica has been studied extensively, the transcriptional changes in the peripheral blood caused by sciatica have not been characterized. This study aimed to characterize the peripheral blood transcriptomic signature for sciatica.

METHODS

We used a microarray to identify differentially expressed genes in the peripheral blood of patients with sciatica compared with that of healthy controls, performed a functional analysis to reveal the peripheral blood transcriptomic signature for sciatica, and conducted a network analysis to identify key genes that contribute to the observed transcriptional changes. The expression levels of these key genes were assessed by qRT-PCR.

RESULTS

We found that 153 genes were differentially expressed in the peripheral blood of patients with sciatica compared with that of healthy controls, and 131 and 22 of these were upregulated and downregulated, respectively. A functional analysis revealed that these differentially expressed genes (DEGs) were strongly enriched for the inflammatory response or immunity. The network analysis revealed that a group of genes, most of which are related to the inflammatory response, played a key role in the dysregulation of these DEGs. These key genes are Toll-like receptor 4, matrix metallopeptidase 9, myeloperoxidase, cathelicidin antimicrobial peptide, resistin and Toll-like receptor 5, and a qRT-PCR analysis validated the higher transcript levels of these key genes in the peripheral blood of patients with sciatica than in that of healthy controls.

CONCLUSION

We revealed inflammatory characteristics that serve as a peripheral blood transcriptomic signature for sciatica and identified genes that are essential for mRNA dysregulation in the peripheral blood of patients with sciatica.

Cerebrospinal fluid biomarkers of neuroinflammation in children with hydrocephalus and shunt malfunction

BACKGROUND

Approximately 30% of cerebrospinal fluid (CSF) shunt systems for hydrocephalus fail within the first year and 98% of all patients will have shunt failure in their lifetime. Obstruction remains the most common reason for shunt failure. Previous evidence suggests elevated pro-inflammatory cytokines in CSF are associated with worsening clinical outcomes in neuroinflammatory diseases. The aim of this study was to determine whether cytokines and matrix metalloproteinases (MMPs) contribute towards shunt failure in hydrocephalus.

METHODS

Using multiplex ELISA, this study examined shunt failure through the CSF protein concentration profiles of select pro-inflammatory and anti-inflammatory cytokines, as well as select MMPs. Interdependencies such as the past number of previous revisions, length of time implanted, patient age, and obstruction or non-obstruction revision were examined. The pro-inflammatory cytokines were IL-1β, IL-2, IL-5, IL-6, IL-8, IL-12, IL-17, TNF-α, GM-CSF, IFN-γ. The anti-inflammatory cytokines were IL-4 and IL-10, and the MMPs were MMP-2, MMP-3, MMP-7, MMP-9. Protein concentration is reported as pg/mL for each analyte.

RESULTS

Patient CSF was obtained at the time of shunt revision operation; all pediatric (< 18), totaling n = 38. IL-10, IL-6, IL-8 and MMP-7 demonstrated significantly increased concentrations in patient CSF for the non-obstructed subgroup. Etiological examination revealed IL-6 was increased in both obstructed and non-obstructed cases for PHH and congenital hydrocephalic patients, while IL-8 was higher only in PHH patients. In terms of number of past revisions, IL-10, IL-6, IL-8, MMP-7 and MMP-9 progressively increased from zero to two past revisions and then remained low for subsequent revisions. This presentation was notably absent in the obstruction subgroup. Shunts implanted for three months or less showed significantly increased concentrations of IL-6, IL-8, and MMP-7 in the obstruction subgroup. Lastly, only patients aged six months or less presented with significantly increased concentration of IL-8 and MMP-7.

CONCLUSION

Non-obstructive cases are reported here to accompany significantly higher CSF cytokine and MMP protein levels compared to obstructive cases for IL-10, IL-6, IL-8, MMP-7 and MMP-9. A closer examination of the definition of obstruction and the role neuroinflammation plays in creating shunt obstruction in hydrocephalic patients is suggested.

Natural Marine and Terrestrial Compounds as Modulators of Matrix Metalloproteinases-2 (MMP-2) and MMP-9 in Alzheimer's Disease

Several studies have reported neuroprotective effects by natural products. A wide range of natural compounds have been investigated, and some of these may play a beneficial role in Alzheimer's disease (AD) progression. Matrix metalloproteinases (MMPs), a family of zinc-dependent endopeptidases, have been implicated in AD. In particular, MMP-2 and MMP-9 are able to trigger several neuroinflammatory and neurodegenerative pathways. In this review, we summarize and discuss existing literature on natural marine and terrestrial compounds, as well as their ability to modulate MMP-2 and MMP-9, and we evaluate their potential as therapeutic compounds for neurodegenerative and neuroinflammatory diseases, with a focus on Alzheimer's disease.

The Role of RECK in Hepatobiliary Neoplasia Reveals Its Therapeutic Potential in NASH

Non-alcoholic fatty liver disease (NAFLD) is a multimorbidity disorder ranging from excess accumulation of fat in the liver (steatosis) to steatohepatitis (NASH) and end-stage cirrhosis, and the development of hepatocellular carcinoma (HCC) in a subset of patients. The defining features of NASH are inflammation and progressive fibrosis. Currently, no pharmaceutical therapies are available for NAFLD, NASH and HCC; therefore, developing novel treatment strategies is desperately needed. Reversion Inducing Cysteine Rich Protein with Kazal motifs (RECK) is a well-known modifier of the extracellular matrix in hepatic remodeling and transition to HCC. More recently, its role in regulating inflammatory and fibrogenic processes has emerged. Here, we summarize the most relevant findings that extend our current understanding of RECK as a regulator of inflammation and fibrosis, and its induction as a potential strategy to blunt the development and progression of NASH and HCC.

The Effect of Immunosuppressive Drugs on MMPs Activity in The Walls of Blood Vessels - A Systematic Review

The current study focuses on the role of MMPs in the pathogenesis of the vascular damage and at the same time it offers the review referring to the influence of the immunosuppressive treatment on this interdependence. Contemporary immunosuppressive treatment constitutes of four groups of medications, such as: calcineurin inhibitors including cyclosporine A and tacrolimus; inhibitors of the inosine monophosphate dehydrogenase - the only agent from this group currently used in transplantation is mycophenalate mofetil (MMF); mTOR inhibitors, consisting of everolimus and glucocorticosteroids. Due to the fact that the properties of immunosuppressive drugs still remain unclear and transplant recipients need to use these medicines every day, knowledge of this should be further expanded. The deceases of the patients with the functioning graft who were diagnosed with the cardiovascular system diseases, constitute 50% of all renal transplant recipients. Immunosuppressive treatment leads to many pathological alterations within the organs and tissues and additionally they undoubtedly affect the activity of MMPs in the wall of the vessels.

Recent Advances in Electrochemical Sensors for the Detection of Biomolecules and Whole Cells

Electrochemical sensors are considered an auspicious tool to detect biomolecules (e.g., DNA, proteins, and lipids), which are valuable sources for the early diagnosis of diseases and disorders. Advances in electrochemical sensing platforms have enabled the development of a new type of biosensor, enabling label-free, non-destructive detection of viability, function, and the genetic signature of whole cells. Numerous studies have attempted to enhance both the sensitivity and selectivity of electrochemical sensors, which are the most critical parameters for assessing sensor performance. Various nanomaterials, including metal nanoparticles, carbon nanotubes, graphene and its derivatives, and metal oxide nanoparticles, have been used to improve the electrical conductivity and electrocatalytic properties of working electrodes, increasing sensor sensitivity. Further modifications have been implemented to advance sensor platform selectivity and biocompatibility using biomaterials such as antibodies, aptamers, extracellular matrix (ECM) proteins, and peptide composites. This paper summarizes recent electrochemical sensors designed to detect target biomolecules and animal cells (cancer cells and stem cells). We hope that this review will inspire researchers to increase their efforts to accelerate biosensor progress-enabling a prosperous future in regenerative medicine and the biomedical industry.

Icariside II attenuates cerebral ischemia/reperfusion-induced blood-brain barrier dysfunction in rats via regulating the balance of MMP9/TIMP1

Cerebral ischemia/reperfusion (I/R) results in harmful consequences during ischemic stroke, especially the disruption of the blood-brain barrier (BBB), which leads to severe hemorrhagic transformation through aggravation of edema and brain hemorrhage. Our previous study demonstrated that icariside II (ICS II), which is derived from Herba Epimedii, attenuates cerebral I/R injury by inhibiting the GSK-3β-mediated activation of autophagy both in vitro and in vivo. However, the effect of ICS II on the BBB remains unclear. Thus, in this study, we investigated the regulation of BBB integrity by ICS II after cerebral I/R injury and further explored the underlying mechanism in rats. Cerebral I/R injury was induced by middle cerebral artery occlusion (MCAO), and the treatment groups were administered ICS II at a dose of 16 mg/kg by gavage twice a day for 3 days. The results showed that ICS II effectively prevented BBB disruption, as evidenced by Evans Blue staining. Moreover, ICS II not only significantly reduced the expression of MMP2/9 but also increased TIMP1 and tight junction protein (occludin, claudin 5, and ZO 1) expression. Intriguingly, ICS II may directly bind to both MMP2 and MMP9, as evidenced by molecular docking. In addition, ICS II also inhibited cerebral I/R-induced apoptosis and ameliorated the Bax/Bcl-2 ratio and cleaved-caspase 3 level. Collectively, our findings reveal that ICS II significantly ameliorates I/R-induced BBB disruption and neuronal apoptosis in MCAO rats by regulating the MMP9/TIMP1 balance and inhibiting the caspase 3-dependent apoptosis pathway.

Matrix Metalloproteinases MMP-2 and MMP-9, Their Inhibitors TIMP-1 and TIMP-2, Vascular Endothelial Growth Factor and sVEGFR-2 as Predictive Markers of Ischemic Retinopathy in Patients with Systemic Sclerosis-Case Series Report

Systemic sclerosis (SSc) is an autoimmune connective tissue disorder associated with multiple organ involvement. The aim of the study was to present two SSc patients who were diagnosed with ischemic retinopathy in both eyes. As a background to our case study, we decided to investigate the imbalance of angiogenesis factors in 25 SSc patients in relation to 25 healthy controls. Assays of matrix metalloproteinases-2 and -9 (MMP-2, MMP-9), tissue inhibitor of metalloproteinases-1 (TIMP-1) and -2 (TIMP-2), vascular endothelial growth factor (VEGF), and soluble VEGF receptor-2 (sVEGFR-2) in blood serum and tears were performed. A significantly increased levels of MMP-9 in serum and tears, (p = 0.0375 and p < 0.001, respectively) as well as VEGF/sVEGFR-2 ratio in tears (p < 0.001) were found in the whole SSc patients group compared with controls, while reduced levels of these parameters in patients with ischemic sclerodermic retinopathy were noted. We also observed decreased level MMP-2 in tears and increased levels of TIMP-2 in blood serum and tears of SSc patients with retinal ischemic changes. MMP-9, MMP-2, TIMP-2, and VEGF/sVEGFR-2 may play a crucial role in ischemic retinal degeneration or retinal reorganization in SSc.

miR-21 mediates nickel nanoparticle-induced pulmonary injury and fibrosis

We and other groups have demonstrated that exposure to nickel nanoparticles (Nano-Ni) results in severe and persistent lung inflammation and fibrosis, but the underlying mechanisms remain unclear. Here, we propose that miR-21 may play an important role in Nano-Ni-induced lung inflammation, injury, and fibrosis. Our dose- and time-response studies demonstrated that exposure of C57BL/6J (WT) mice to Nano-Ni resulted in upregulation of miR-21, proinflammatory cytokines, and profibrotic mediators. Histologically, exposure to Nano-Ni caused severe pulmonary inflammation and fibrosis. Based on the dose- and time-response studies, we chose a dose of 50 µg of Nano-Ni per mouse to compare the effects of Nano-Ni on WT with those on miR-21 KO mouse lungs. At day 3 post-exposure, Nano-Ni caused severe acute lung inflammation and injury that were reflected by increased neutrophil count, CXCL1/KC level, LDH activity, total protein concentration, MMP-2/9 protein levels and activities, and proinflammatory cytokines in the BALF or lung tissues from WT mice, which were confirmed histologically. Although Nano-Ni had similar effects on miR-21 KO mice, the above-mentioned levels were significantly lower than those in WT mice. Histologically, lungs from WT mice exposed to Nano-Ni had infiltration of a large number of polymorphonuclear (PMN) cells and macrophages in the alveolar space and interstitial tissues. However, exposure of miR-21 KO mice to Nano-Ni only caused mild acute lung inflammation and injury. At day 42 post-exposure, Nano-Ni caused extensive pulmonary fibrosis and chronic inflammation in the WT mouse lungs. However, exposure of miR-21 KO mice to Nano-Ni only caused mild lung fibrosis and chronic lung inflammation. Our results also showed that exposure to Nano-Ni caused upregulation of TGF-β1, phospho-Smad2, COL1A1, and COL3A1 in both WT and miR-21 KO mouse lungs. However, levels were significantly lower in miR-21 KO mice than in WT mice, except TGF-β1, which was similar in both kinds of mice. Decreased expression of Smad7 was observed in WT mouse lungs, but not in miR-21 KO mice. Our results demonstrated that knocking out miR-21 ameliorated Nano-Ni-induced pulmonary inflammation, injury, and fibrosis, suggesting the important role of miR-21 in Nano-Ni-induced pulmonary toxicity.

Nucleobindin-1 regulates ECM degradation by promoting intra-Golgi trafficking of MMPs

Matrix metalloproteinases (MMPs) degrade several ECM components and are crucial modulators of cell invasion and tissue organization. Although much has been reported about their function in remodeling ECM in health and disease, their trafficking across the Golgi apparatus remains poorly understood. Here we report that the cis-Golgi protein nucleobindin-1 (NUCB1) is critical for MMP2 and MT1-MMP trafficking along the Golgi apparatus. This process is Ca2+-dependent and is required for invasive MDA-MB-231 cell migration as well as for gelatin degradation in primary human macrophages. Our findings emphasize the importance of NUCB1 as an essential component of MMP transport and its overall impact on ECM remodeling.

Homotrimeric MMP-9 is an active hitchhiker on alpha-2-macroglobulin partially escaping protease inhibition and internalization through LRP-1

Proteolysis is a crucial process in life, tightly controlled by numerous natural protease inhibitors. In human blood, alpha-2-macroglobulin is an emergency protease inhibitor preventing coagulation and damage to endothelia and leukocytes. With the use of a unique protease trapping mechanism, alpha-2-macroglobulin lures active proteases into its snap-trap, shields these from potential substrates and 'flags' their complex for elimination by receptor-mediated endocytosis. Matrix metalloprotease-9/gelatinase B is a secreted protease increased in blood of patients with inflammations, vascular disorders and cancers. Matrix metalloprotease-9 occurs as monomers and stable homotrimers, but the reason for their co-existence remains obscure. We discovered that matrix metalloprotease-9 homotrimers undergo reduced anti-proteolytic regulation by alpha-2-macroglobulin and are able to travel as a proteolytically active hitchhiker on alpha-2-macroglobulin. As a comparison, we revealed that monomeric active matrix metalloprotease-9 is efficiently trapped by human plasma alpha-2-macroglobulin and this masks the detection of activated matrix metalloprotease-9 with standard analysis techniques. In addition, we show that alpha-2-macroglobulin/trimer complexes escape clearance through the receptor low-density lipoprotein receptor-related protein 1, also known as the alpha-2-macroglobulin receptor. Thus, the biochemistry and biology of matrix metalloprotease-9 monomers and trimers are completely different as multimerization enables active matrix metalloprotease-9 to partially avoid alpha-2-macroglobulin regulation both by direct protease inhibition and by removal from the extracellular space by receptor-mediated endocytosis. Finally, for the biomarker field, the analysis of alpha-2-macroglobulin/protease complexes with upgraded technology is advocated as a quotum for protease activation in human plasma samples.

Mechanisms in blood-brain barrier opening and metabolism-challenged cerebrovascular ischemia with emphasis on ischemic stroke

Stroke is the leading cause of disability among adults as well as the 2nd leading cause of death globally. Ischemic stroke accounts for about 85% of strokes, and currently, tissue plasminogen activator (tPA), whose therapeutic window is limited to up to 4.5 h for the appropriate population, is the only FDA approved drug in practice and medicine. After a stroke, a cascade of pathophysiological events results in the opening of the blood-brain barrier (BBB) through which further complications, disabilities, and mortality are likely to threaten the patient's health. Strikingly, tPA administration in eligible patients might cause hemorrhagic transformation and sustained damage to BBB integrity. One must, therefore, delineate upon stroke onset which cellular and molecular factors mediate BBB permeability as well as what key roles BBB rupture plays in the pathophysiology of stroke. In this review article, given our past findings of mechanisms underlying BBB opening in stroke animal models, we elucidate cellular, subcellular, and molecular factors involved in BBB permeability after ischemic stroke. The contribution of each factor to stroke severity and outcome is further discussed. Determinant factors in BBB permeability and stroke include mitochondria, miRNAs, matrix metalloproteinases (MMPs), immune cells, cytokines, chemokines, and adhesion proteins. Once these factors are interrogated and their roles in the pathophysiology of stroke are determined, novel targets for drug discovery and development can be uncovered in addition to novel therapeutic avenues for human stroke management.

Selected Matrix Metalloproteinases (MMP-2, MMP-7) and Their Inhibitor (TIMP-2) in Adult and Pediatric Cancer

The tumor microenvironment (TME) consists of numerous biologically relevant elements. One of the most important components of the TME is the extracellular matrix (ECM). The compounds of the ECM create a network that provides structural and biochemical support to surrounding cells. The most important substances involved in the regulation of the ECM degradation process are matrix metalloproteinases (MMPs) and their endogenous inhibitors (tissue inhibitors of metalloproteinases, TIMPs). The disruption of the physiological balance between MMP activation and deactivation could lead to progression of various diseases such as cardiovascular disease, cancer, fibrosis arthritis, chronic tissue ulcers, pathologies of the nervous system (such as stroke and Alzheimer's disease), periodontitis, and atheroma. MMP-TIMP imbalance results in matrix proteolysis associated with various pathological processes such as tumor invasion. The present review discusses the involvement of two MMPs, MMP-2 and MMP-7, in cancer pathogenesis. These two MMPs have been proven in several studies, conducted mostly on adults, to make an important contribution to cancer development and progression. In the current review, several studies that indicate the importance of MMP-TIMP balance determination for the pediatric population are also highlighted. The authors of this review believe that carrying out biochemical and clinical studies focused on metalloproteinases and their inhibitors in tumors in children will be of great relevance for future patient diagnosis, determination of a prognosis, and monitoring of therapy.

Hub Proteins Involved in RAW 264.7 Macrophages Exposed to Direct Current Electric Field

At present, studies on macrophage proteins mainly focus on biological stimuli, with less attention paid to the responses of macrophage proteins to physical stimuli, such as electric fields. Here, we exploited the electric field-sensitive hub proteins of macrophages. RAW 264.7 macrophages were treated with a direct current electric field (dcEF) (200 mV/mm) for four hours, followed by RNA-Seq analysis. Differentially expressed genes (DEGs) were obtained, followed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) and protein–protein interaction (PPI) analysis. Eight qPCR-verified DEGs were selected. Subsequently, three-dimensional protein models of DEGs were modeled by Modeller and Rosetta, followed by molecular dynamics simulation for 200 ns with GROMACS. Finally, dcEFs (10, 50, and 500 mV/mm) were used to simulate the molecular dynamics of DEG proteins for 200 ns, followed by trajectory analysis. The dcEF has no obvious effect on RAW 264.7 morphology. A total of 689 DEGs were obtained, and enrichment analysis showed that the steroid biosynthesis pathway was most affected by the dcEF. Moreover, the three-dimensional protein structures of hub proteins were constructed, and trajectory analysis suggested that the dcEF caused an increase in the atomic motion of the protein in a dcEF-intensity-dependent manner. Overall, we provide new clues and a basis for investigating the hub proteins of macrophages in response to electric field stimulation.

Electrospun Resveratrol-Loaded Polyvinylpyrrolidone/Cyclodextrin Nanofibers and Their Biomedical Applications

Resveratrol is a naturally occurring polyphenol compound which has been shown to possess antioxidant and anti-inflammatory properties. However, its pharmaceutical applications are limited by its poor water solubility. In this study, we used electrospinning technology to synthesize nanofibers of polyvinylpyrrolidone (PVP) and hydroxypropyl-β-cyclodextrin (HPBCD) loaded with resveratrol. We used X-ray diffractometry to analyze crystalline structure, Fourier transform infrared spectroscopy to determine intermolecular hydrogen bonding, antioxidant assays to measure antioxidant activity, and Franz diffusion cells to evaluate skin penetration. Our results showed that the aqueous solubility of resveratrol nanofibers was greatly improved (by more than 20,000-fold) compared to the pure compound. Analysis of physicochemical properties demonstrated that following nanofiber formation, resveratrol was converted from a crystalline to amorphous structure, and resveratrol formed new intermolecular bonds with PVP and HPBCD. Moreover, resveratrol nanofibers showed good antioxidant activity. In addition, the skin penetration ability of resveratrol in the nanofiber formulation was greater than that of pure resveratrol. Furthermore, resveratrol nanofibers suppressed particulate matter (PM)-induced expression of inflammatory proteins (COX-2 and MMP-9) in HaCaT keratinocytes. Therefore, resveratrol-loaded nanofibers can effectively improve the solubility and physicochemical properties of resveratrol, and may have potential applications as an antioxidant and anti-inflammatory formulation for topical skin application.

Matrix Metalloproteinases as New Targets in Alzheimer's Disease: Opportunities and Challenges

Although matrix metalloproteinases (MMPs) are implicated in the regulation of numerous physiological processes, evidence of their pathological roles have also been obtained in the last decades, making MMPs attractive therapeutic targets for several diseases. Recent discoveries of their involvement in central nervous system (CNS) disorders, and in particular in Alzheimer's disease (AD), have paved the way to consider MMP modulators as promising therapeutic strategies. Over the past few decades, diverse approaches have been undertaken in the design of therapeutic agents targeting MMPs for various purposes, leading, more recently, to encouraging developments. In this article, we will present recent examples of inhibitors ranging from small molecules and peptidomimetics to biologics. We will also discuss the scientific knowledge that has led to the development of emerging tools and techniques to overcome the challenges of selective MMP inhibition.

Initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin

BACKGROUND

Calvaria skin has a reduced thickness, and its initial damage produced by irradiation was scarcely reported. We aimed to identify the initial effects of x-ray irradiation in the rat calvaria skin.

METHODS

After approval by the Animal Ethical Committee, calvaria skin sections of five Wistar rats per time point were evaluated on days 4, 9, 14, and 25 following a single 15-Gy x-ray irradiation of the head. The control group was composed of five rats and evaluated on day 4. Sections were assessed using hematoxylin-eosin and Masson's trichrome staining for morphology, inflammation, and fibrosis. Fibrosis was also evaluated by the collagen maturation index from Picrosirius red staining and by cell proliferation using the immunohistochemistry, after 5-bromo-2-deoxyuridine intraperitoneal injection.

RESULTS

In irradiated rats, we observed a reduction in epithelial cell proliferation (p = 0.004) and in matrix metalloproteinase-9 expression (p < 0.001), an increase in the maturation index, and with a predominance in the type I collagen fibers, on days 9 and 14 (1.19 and 1.17, respectively). A progressive disorganization in the morphology of the collagen fibers at all time points and changes in morphology of the sebaceous gland cells and hair follicle were present until day 14.

CONCLUSIONS

The initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin was a change in the normal morphology of collagen fibers to an amorphous aspect, a temporary absence of the sebaceous gland and hair follicles, and without a visible inflammatory process, cell proliferation, or fibrosis process in the dermis.

The Role of Matrix Metalloproteinases (MMP-2 and MMP-9) in Ageing and Longevity: Focus on Sicilian Long-Living Individuals (LLIs)

Extracellular matrix metalloproteinases (MMPs) are a group of proteins that activate substrates by enzymatic cleavage and, on the basis of their activities, have been demonstrated to play a role in ageing. Thus, in order to gain insight into the pathophysiology of ageing and to identify new markers of longevity, we analysed the activity levels of MMP-2 and MMP-9 in association with some relevant haematochemical parameters in a Sicilian population, including long-living individuals (LLIs, ≥95 years old). A cohort of 154 healthy subjects (72 men and 82 women) of different ages (age range 20-112) was recruited. The cohort was divided into five subgroups: the first group with subjects less than 40 years old, the second group ranging from 40 to 64 years old, the third group ranging from 65 to 89 years old, the fourth group ranging from 90 to 94 years old, and the fifth group with subjects more than 95 years old. A relationship was observed between LLIs and MMP-2, but not between LLIs and MMP-9. However, in the LLI group, MMP-2 and MMP-9 values were significantly correlated. Furthermore, in LLIs, we found a positive correlation of MMP-2 with the antioxidant catabolite uric acid and a negative correlation with the inflammatory marker C-reactive protein. Finally, in LLIs MMP-9 values correlated directly both with cholesterol and with low-density lipoproteins. On the whole, our data suggest that the observed increase of MMP-2 in LLIs might play a positive role in the attainment of longevity. This is the first study that shows that serum activity of MMP-2 is increased in LLIs as compared to younger subjects. As far as we are concerned, it is difficult to make wide-ranging conclusions/assumptions based on these observations in view of the relatively small sample size of LLIs. However, this is an important starting point. Larger-scale future studies will be required to clarify these findings including the link with other systemic inflammatory and antioxidant markers.

The Oak-wood Extract Robuvit® Improves Recovery and Oxidative Stress after Hysterectomy: A Randomized, Double-blind, Placebo-controlled Pilot Study

Hysterectomy has a variety of medical indications and improves pre-operative symptoms but might compromise the quality of life during recovery due to symptoms such as fatigue, headache, nausea, depression, or pain. The aim of the present study was to determine the effect of a standardized extract from French oak wood (Quercus robur) containing at least 40% polyphenols of the ellagitannins class, Robuvit^®, on convalescence and oxidative stress of women after hysterectomy. Recovery status was monitored with the SF-36 questionnaire. The supplementation with Robuvit^® (300 mg/day) during 4 weeks significantly improved general and mental health, while under placebo some items significantly deteriorated. Oxidative stress and enhancement of MMP–9 activity was significantly reduced by Robuvit^® versus placebo. After 8 weeks of intervention, the patients’ condition improved independently of the intervention. Our results suggest that the use of Robuvit^® as a natural supplement relieves post-operative symptoms of patients after hysterectomy and reduces oxidative stress. The study was registered with ID ISRCTN 11457040 (13/09/2019).

The effect and mechanism of combination of total paeony glycosides and total ligustici phenolic acids against focal cerebral ischemia

The root of Paeonia lactiflora Pall. (Chishao, CS) and Ligusticum chuanxiong Hort. (Chuanxiong, CX) were widely used as a drug pair in Chinese Medicine, and the combination of CS and CX showed a more significant inhibition on neuronal apoptosis in our previous study. In the present study, total paeony glycosides (TPGs) from CS and total ligustici phenolic acids (TLPAs) from CX were combined to evaluate the synergistic effects against focal cerebral ischemia both in vitro and in vivo. The combination of TPGs and TLPAs at 7:3 had the best anti-oxidative stress and anti-inflammatory effect on OGD-induced HUVEC. Additionally, the infarction area proportion and neuron apoptosis of rats by TPGs:TLPAs (7:3) was significantly lower than their alone in MCAO rats. Moreover, TPGs: TLPAs of 7:3 showed a more significant effect on decreasing the expression of MMP-2 and MMP-9, and increasing the protein expression or mRNA level of TIMP-1 than other combinations. The optimal ratio of TPGs and TLPAs at 7:3 could bring more remarkable protective effects against focal cerebral ischemia in MCAO rats by alleviating oxidative stress, inflammatory and neuronal apoptosis to protect the blood-brain barrier. Overall, the present study provided benefical evidence for clinical application of CS and CX as a "drug pair".

A novel CNS-homing peptide for targeting neuroinflammatory lesions in experimental autoimmune encephalomyelitis

Using phage peptide library screening, we identified peptide-encoding phages that selectively home to the inflamed central nervous system (CNS) of mice with experimental autoimmune encephalomyelitis (EAE), a model of human multiple sclerosis (MS). A phage peptide display library encoding cyclic 9-amino-acid random peptides was first screened ex-vivo for binding to the CNS tissue of EAE mice, followed by in vivo screening in the diseased mice. Phage insert sequences that were present at a higher frequency in the CNS of EAE mice than in the normal (control) mice were identified by DNA sequencing. One of the phages selected in this manner, denoted as MS-1, was shown to selectively recognize CNS tissue in EAE mice. Individually cloned phages with this insert preferentially homed to EAE CNS after an intravenous injection. Similarly, systemically-administered fluorescence-labeled synthetic MS-1 peptide showed selective accumulation in the spinal cord of EAE mice. We suggest that peptide MS-1 might be useful for targeted drug delivery to CNS in EAE/MS.

Microglial NLRP3 inflammasome activation in multiple sclerosis

Multiple sclerosis (MS) is a chronic, autoimmune and neuroinflammatory disease of the central nervous system (CNS) mediated by autoreactive T cells directed against myelin antigens. Although the crucial role of adaptive immunity is well established in MS, the contribution of innate immunity has only recently been appreciated. Microglia are the main innate immune cells of the CNS. Similar to other myeloid cells, microglia recognize both exogenous and host-derived endogenous danger signals through pattern recognition receptors (PRRs) localized on their cell surface such as Toll Like receptor 4, or in the cytosol such as NLRP3. The second one is the sensor protein of the multi-molecular NLRP3 inflammasome complex in activated microglia that promotes the maturation and secretion of proinflammatory cytokines, interleukin-1β and interleukin-18. Overactivation of microglia and aberrant activation of the NLRP3 inflammasome have been implicated in the pathogenesis of MS. Indeed, experimental data, together with post-mortem and clinical studies have revealed an increased expression of NLRP3 inflammasome complex elements in microglia and other immune cells. In this review, we focus on microglial NLRP3 inflammasome activation in MS. First, we overview the basic knowledge about MS, microglia and the NLRP3 inflammasome. Then, we summarize studies about microglial NLRP3 inflammasome activation in MS and its animal models. We also highlight experimental therapeutic approaches that target different steps of NLRP inflammasome activation. Finally, we discuss future research avenues and new methods in this rapidly evolving area.

Matrix metalloproteinase-2: Not (just) a "hero" of the past

The 72-kDa type IV collagenase or gelatinase A is the second member of the matrix metalloproteinase family, MMP-2. Since the discovery of its first two substrates within components of the extracellular matrix, denatured interstitial type I collagen and native type IV collagen, the roles and various levels of regulation of MMP-2 have been intensively studied, mainly in vitro. Its (over)expression in most if not all tumors was considered a hallmark of cancer aggressiveness and boosted investigations aiming at its inhibition. Unfortunately, the enthusiasm subsided like a soufflé after clinical trial failures, mostly because of insufficient knowledge of in vivo MMP-2 activities and detrimental side effects of broad-spectrum MMP inhibition. Nowadays, MMP-2 remains a major topic of interest in research, the second in the MMP family after MMP-9. This review presents a broad overview of the major features of this protease. This knowledge is crucial to identify diagnostic or therapeutic strategies focusing on MMP-2. In this sense, recent publications and clinical trials underline the potential value of measuring circulating or tissular MMP-2 levels as diagnostic or prognostic tools, or as a useful secondary outcome for therapies against other primary targets. Direct MMP-2 inhibition has benefited from substantial progress in the design of more specific inhibitors but their in vivo application remains challenging but certainly worth the efforts it receives.