Edaravone dexborneol alleviates ischemic injury and neuroinflammation by modulating microglial and astrocyte polarization while inhibiting leukocyte infiltration

Poststroke inflammation is essential in the mechanism of secondary injury, and it is orchestrated by resident microglia, astrocytes, and circulating immune cells. Edaravone dexborneol (EDB) is a combination of edaravone and borneol that has been identified as a clinical protectant for stroke management. In this study, we verified the anti-inflammatory effect of EDB in the mouse model of ischemia and investigated its modulatory action on inflammation-related cells. C57BL/6 male mice, which had the transient middle cerebral artery occlusion (tMCAO), were treated (i.p.) with EDB (15 mg/kg). EDB administration significantly reduced the brain infarction and improved the sensorimotor function after stroke. And EDB alleviated the neuroinflammation by restraining the polarization of microglia/macrophages and astrocyte toward proinflammatory phenotype and inhibiting the production of proinflammatory cytokines (such as IL-1β, TNF-α, and IL-6) and chemokines (including MCP-1 and CXCL1). Furthermore, EDB ameliorated the MCAO-induced impairment of Blood-brain barrier (BBB) by suppressing the degradation of tight junction protein and attenuated the accumulation of peripheral leukocytes in the ischemic brain. Additionally, systemic EDB administration inhibited the macrophage phenotypic shift toward the M1 phenotype and the macrophage-dependent inflammatory response in the spleen and blood. Collectively, EDB protects against ischemic stroke injury by inhibiting the proinflammatory activation of microglia/macrophages and astrocytes and through reduction by invasion of circulating immune cells, which reduces central and peripheral inflammation following stroke.

Macrophages coordinate immune response to laser-induced injury via extracellular traps

BACKGROUND

Retinal degeneration results from disruptions in retinal homeostasis due to injury, disease, or aging and triggers peripheral leukocyte infiltration. Effective immune responses rely on coordinated actions of resident microglia and recruited macrophages, critical for tissue remodeling and repair. However, these phagocytes also contribute to chronic inflammation in degenerated retinas, yet the precise coordination of immune response to retinal damage remains elusive. Recent investigations have demonstrated that phagocytic cells can produce extracellular traps (ETs), which are a source of self-antigens that alter the immune response, which can potentially lead to tissue injury.

METHODS

Innovations in experimental systems facilitate real-time exploration of immune cell interactions and dynamic responses. We integrated in vivo imaging with ultrastructural analysis, transcriptomics, pharmacological treatments, and knockout mice to elucidate the role of phagocytes and their modulation of the local inflammatory response through extracellular traps (ETs). Deciphering these mechanisms is essential for developing novel and enhanced immunotherapeutic approaches that can redirect a specific maladaptive immune response towards favorable wound healing in the retina.

RESULTS

Our findings underscore the pivotal role of innate immune cells, especially macrophages/monocytes, in regulating retinal repair and inflammation. The absence of neutrophil and macrophage infiltration aids parenchymal integrity restoration, while their depletion, particularly macrophages/monocytes, impedes vascular recovery. We demonstrate that macrophages/monocytes, when recruited in the retina, release chromatin and granular proteins, forming ETs. Furthermore, the pharmacological inhibition of ETosis support retinal and vascular repair, surpassing the effects of blocking innate immune cell recruitment. Simultaneously, the absence of ETosis reshapes the inflammatory response, causing neutrophils, helper, and cytotoxic T-cells to be restricted primarily in the superficial capillary plexus instead of reaching the damaged photoreceptor layer.

CONCLUSIONS

Our data offer novel insights into innate immunity's role in responding to retinal damage and potentially help developing innovative immunotherapeutic approaches that can shift the immune response from maladaptive to beneficial for retinal regeneration.

Evaluation of the therapeutic effects of oestradiol on the systemic inflammatory response and on lung injury caused by the occlusion of the proximal descending aorta in male rats

OBJECTIVES

Ischaemia and reperfusion-induced microvascular dysfunction is a serious problem encountered during a variety surgical procedures, leading to systemic inflammation and affecting remote organs, specially the lungs. 17β-Oestradiol reduces pulmonary repercussions from various acute lung injury forms. Here, we focused on the 17β-oestradiol therapeutic effects after aortic ischaemia and reperfusion (I/R) by evaluating lung inflammation.

METHODS

Twenty-four Wistar rats were submitted to I/R by insufflation of a 2-F catheter in thoracic aorta for 20 min. Reperfusion took 4 h and 17β-oestradiol (280 µg/kg, i.v.) was administered after 1 h of reperfusion. Sham-operated rats were controls. Bronchoalveolar lavage was performed and lung samples were prepared for histopathological analysis and tissue culture (explant). Interleukin (IL)-1β, IL-10 and tumour necrosis factor-α were quantified.

RESULTS

After I/R, higher number of leukocytes in bronchoalveolar lavage were reduced by 17β-oestradiol. The treatment also decreased leukocytes in lung tissue. I/R increased lung myeloperoxidase expression, with reduction by 17β-oestradiol. Serum cytokine-induced neutrophil chemoattractant 1 and IL-1β increased after I/R and 17β-oestradiol decreased cytokine-induced neutrophil chemoattractant 1. I/R increased IL-1β and IL-10 in lung explants, reduced by 17β-oestradiol.

CONCLUSIONS

Our results showed that 17β-oestradiol treatment performed in the period of reperfusion, modulated the systemic response and the lung repercussions of I/R by thoracic aortic occlusion. Thus, we can suggest that 17β-oestradiol might be a supplementary approach leading the lung deterioration after aortic clamping in surgical procedures.

Thermogels containing sulfated hyaluronan as novel topical therapeutics for treatment of ocular surface inflammation

The development of long lasting therapeutic agents is critically important for efficient treatment of chronic diseases. We herein report a rational strategy to develop a therapeutic thermogel featured with prolonged anti-inflammatory and corneal-protective effects. Specifically, a hyaluronic acid with different sulfation degrees and an amine-terminated poly(N-isopropylacrylamide) are conjugated to achieve the thermogels. In vitro studies reveal that the thermogels are highly biocompatible to statens seruminstitut rabbit cornea cells and their anti-inflammatory properties are strongly dependent on the sulfation degree. In a rabbit model of ocular inflammation, single-dose topical administration of a thermogel formulation could repair defects in corneal epithelium (∼99% thickness restored), prevent corneal cell apoptosis (∼68.3% cells recovered), and suppress ocular surface inflammation (∼4-fold decrease) for a follow-up period of 7 days. This high treatment efficacy of the thermogel can be attributed to its potent inhibition in selectin-mediated leukocyte infiltration as well as effective corneal protection. These findings show a great promise for topical treatment of ocular inflammation and advancement of ophthalmic formulations using the bioactive thermogel as a therapeutic component that is not rapidly cleared from the eye and thus considerably reduces administration times.

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Sulfated hyaluronan thermogels served as intrinsic therapeutic agents.

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Thermogels exert inhibitory effects on selectin-mediated leukocyte infiltration.

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Sulfation degree is a key to achieve superior therapeutic thermogels.

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Highly sulfated agent reveals potent anti-inflammatory/corneal-protective effects.

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Single dose reduces corneal inflammation by 4-folds at 7 days post-instillation.

Inhibition of microsomal prostaglandin E synthase-1 ameliorates acute lung injury in mice

Background

To examine the effects of BI 1029539 (GS-248), a novel selective human microsomal prostaglandin E synthase-1 (mPGES-1) inhibitor, in experimental models of acute lung injury (ALI) and sepsis in transgenic mice constitutively expressing the mPGES1 (Ptges) humanized allele.

Methods

Series 1: Lipopolysaccharide (LPS)-induced ALI. Mice were randomized to receive vehicle, BI 1029539, or celecoxib. Series 2: Cecal ligation and puncture-induced sepsis. Mice were randomized to receive vehicle or BI 1029539.

Results

Series 1: BI 1029539 or celecoxib reduced LPS-induced lung injury, with reduction in neutrophil influx, protein content, TNF-ɑ, IL-1β and PGE₂ levels in bronchoalveolar lavage (BAL), myeloperoxidase activity, expression of mPGES-1, cyclooxygenase (COX)-2 and intracellular adhesion molecule in lung tissue compared with vehicle-treated mice. Notably, prostacyclin (PGI₂) BAL concentration was only lowered in celecoxib-treated mice. Series 2: BI 1029539 significantly reduced sepsis-induced BAL inflammatory cell recruitment, lung injury score and lung expression of mPGES-1 and inducible nitric oxide synthase. Treatment with BI 1029539 also significantly prolonged survival of mice with severe sepsis. Anti-inflammatory and anti-migratory effect of BI 1029539 was confirmed in peripheral blood leukocytes from healthy volunteers.

Conclusions

BI 1029539 ameliorates leukocyte infiltration and lung injury resulting from both endotoxin-induced and sepsis-induced lung injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03016-9.

Recombinant annexin A2 inhibits peripheral leukocyte activation and brain infiltration after traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a significant cause of death and disability worldwide. The TLR4-NFκB signaling cascade is the critical pro-inflammatory activation pathway of leukocytes after TBI, and modulating this signaling cascade may be an effective therapeutic target for treating TBI. Previous studies indicate that recombinant annexin A2 (rA2) might be an interactive molecule modulating the TLR4-NFκB signaling; however, the role of rA2 in regulating this signaling pathway in leukocytes after TBI and its subsequent effects have not been investigated.

METHODS

C57BL/6 mice were subjected to TBI and randomly divided into groups that received intraperitoneal rA2 or vehicle at 2 h after TBI. The peripheral leukocyte activation and infiltrating immune cells were examined by flow cytometry, RT-qPCR, and immunostaining. The neutrophilic TLR4 expression on the cell membrane was examined by flow cytometry and confocal microscope, and the interaction of annexin A2 with TLR4 was assessed by co-immunoprecipitation coupled with Western blotting. Neuroinflammation was measured via cytokine proteome profiler array and RT-qPCR. Neurodegeneration was determined by Western blotting and immunostaining. Neurobehavioral assessments were used to monitor motor and cognitive function. Brain tissue loss was assessed via MAP2 staining.

RESULTS

rA2 administration given at 2 h after TBI significantly attenuates neutrophil activation and brain infiltration at 24 h of TBI. In vivo and in vitro data show that rA2 binds to and reduces TLR4 expression on the neutrophil surface and suppresses TLR4/NFκB signaling pathway in neutrophils at 12 h after TBI. Furthermore, rA2 administration also reduces pro-inflammation of brain tissues within 24 h and neurodegeneration at 48 h after TBI. Lastly, rA2 improves long-term sensorimotor ability and cognitive function, and reduces brain tissue loss at 28 days after TBI.

CONCLUSIONS

Systematic rA2 administration at 2 h after TBI significantly inhibits activation and brain infiltration of peripheral leukocytes, especially neutrophils at the acute phase. Consequently, rA2 reduces the detrimental brain pro-inflammation-associated neurodegeneration and ultimately ameliorates neurological deficits after TBI. The underlying molecular mechanism might be at least in part attributed to rA2 bindings to pro-inflammatory receptor TLR4 in peripheral leukocytes, thereby blocking NFκB signaling activation pathways following TBI.

IL-31 transgenic mice show reduced allergen-induced lung inflammation

Interleukin-31 (IL-31) is a Th2 cell-derived cytokine that has been closely linked to pruritic skin inflammation. More recently, enhanced IL-31 serum levels have also been observed in patients with allergic rhinitis and allergic asthma. Therefore, the main aim of this study was to unravel the contribution of IL-31 to allergen-induced lung inflammation. We analyzed lung inflammation in response to the timothy grass (Phleum pratense) pollen allergen Phl p 5 in C57BL/6 wild-type (wt) mice, IL-31 transgenic (IL-31tg) mice, and IL-31 receptor alpha-deficient animals (IL-31RA-/- ). IL-31 and IL-31RA levels were monitored by qRT-PCR. Cellular infiltrate in bronchoalveolar lavage fluid (BALF) and lung tissue inflammation, mucus production as well as epithelial thickness were measured by flow cytometry and histomorphology. While allergen challenge induced IL-31RA expression in lung tissue of wt and IL-31tg mice, high IL-31 expression was exclusively observed in lung tissue of IL-31tg mice. Upon Phl p 5 challenge, IL-31tg mice showed reduced numbers of leukocytes and eosinophils in BALF and lung tissue as well as diminished mucin expression and less pronounced epithelial thickening compared to IL-31RA-/- or wt animals. These findings suggest that the IL-31/IL-31RA axis may regulate local, allergen-induced inflammation in the lungs.

let-7g counteracts endothelial dysfunction and ameliorating neurological functions in mouse ischemia/reperfusion stroke model

Stroke is a debilitating disease, accounting for almost 20% of all hospital visits, and 8% of all fatalities in the United States in 2017. Following an ischemic attack, inflammatory processes originating from endothelial cells within the brain microvasculature can induce many toxic effects into the impacted area, from both sides of the blood brain barrier (BBB). In addition to increased BBB permeability, impacted brain microvascular endothelial cells can recruit macrophages and other immune cells from the periphery and can also trigger the activation of microglia and astrocytes within the brain. We have identified a key microRNA, let-7g, which levels were drastically diminished as consequence of transient middle cerebral artery occlusion (tMCAO) in vivo and oxygen-glucose deprivation (OGD) in vitro ischemia/reperfusion conditions, respectively. We have observed that let-7g* liposome-based delivery is capable of attenuating inflammation after stroke, reducing BBB permeability, limiting brain infiltration by CD3+CD4+ T-cells and Ly6G+ neutrophils, lessening microglia activation and neuronal death. These effects consequently improved clinical outcomes, shown by mitigating post-stroke gait asymmetry and extremity motor function. Due to the role of the endothelium in propagating the effects of stroke and other inflammation, treatments which can reduce endothelial inflammation and limit ischemic damage and improving recovery after a stroke are required. Our findings demonstrate a critical link between the CNS inflammation and the immune system reaction and lay important groundwork for future stroke pharmacotherapies.

Neuropilin-1 receptor in the rapid and selective estrogen-induced neurovascular remodeling of rat uterus

Sympathetic nerves innervate most organs and regulate organ blood flow. Specifically, in the uterus, estradiol (E2) elicits rapid degeneration of sympathetic axons and stimulates the growth of blood vessels. Both physiological remodeling processes, critical for reproduction, have been extensively studied but as independent events and are still not fully understood. Here, we examine the neuropilin-1 (NRP1), a shared receptor for axon guidance and angiogenic factors. Systemic estradiol or vehicle were chronically injected to prepubertal rats and uterine and sympathetic chain sections immunostained for NRP1. Uterine semaphorin-3A mRNA was evaluated by in situ hybridization. Control sympathetic uterine-projecting neurons (1-month-old) expressed NRP1 in their somas but not in their intrauterine terminal axons. Estradiol did not affect NRP1 in the distal ganglia. However, at the entrance of the organ, some sympathetic NRP1-positive nerves were recognized. Vascular NRP1 was confined to intrauterine small-diameter vessels in both hormonal conditions. Although the overall pattern of NRP1-IR was not affected by E2 treatment, a subpopulation of infiltrated eosinophil leukocytes showed immunoreactivity for NRP1. Sema3A transcripts were detected in this cellular type as well. No NRP1-immunoreactive axons nor infiltrated eosinophils were visualized in other estrogenized pelvic organs. Together, these data suggest the involvement of NRP1/Sema3A signaling in the selective E2-induced uterine neurovascular remodeling. Our data support a model whereby NRP1 could coordinate E2-induced uterine neurovascular remodeling, acting as a positive regulator of growth when expressed in vessels and as a negative regulator of growth when expressed on axons.

Hypertonic saline reduces cell infiltration into the lungs after brain death in rats

BACKGROUND

Lung transplantation is a treatment method for end stage lung disease, but the availability of donor lungs remains a major constraint. Brain death (BD) induces hemodynamic instability with microcirculatory hypoperfusion and increased inflammation, leading to pulmonary dysfunction. Hypertonic saline solution (HSS) is a volume expander possessing immunomodulatory effects. This study evaluated the influence of HSS on pulmonary dysfunction and inflammation in a rat model of BD.

METHODS

BD was induced by inflation of an intracranial balloon catheter. Rats were divided into [1]: Sham, without BD [2]; NS, NaCl treatment (0.9%, 4 mL/kg, i.v.) immediately after BD [3]; HSS₁, HSS treatment (NaCl 7.5%, 4 mL/kg, i.v.) immediately after BD; and [4] HSS₆₀, HSS treatment 60 min post BD. All groups were analyzed after 360 min.

RESULTS

Animals subjected to BD exhibited increased exhaled O₂ and decreased CO₂.The number of leukocytes in the lungs was significantly increased in the NS group (p = 0.002) and the HSS treatment was able to reduce it (HSS₁, p = 0.018 and HSS₆₀ = 0.030). In parallel, HSS-treated rats showed reduced levels of ICAM-1 expression, which was increased in the NS compared to Sham group. Lung edema was found increased in the NS group animals compared to Sham and no effect of the HSS treatment was observed. There were no differences among the groups in terms of TNF-α, VEGF, and CINC-1 lung concentrations.

CONCLUSIONS

HSS is capable of reducing inflammatory cell infiltration into the lung after BD induction, which is associated with the reduction of ICAM-1 expression in organ vessels.

A Novel Modality for Functional Imaging in Acute Intervertebral Disk Herniation via Tracking Leukocyte Infiltration

PURPOSE

Inflammation plays a key role in the progression of intervertebral disk (IVD) herniation and associated low back pain. However, real-time spatial diagnosis of inflammation associated with acute disk herniation has not been investigated. We sought to detect local neutrophil and macrophage infiltration near disk herniation via the formyl peptide receptor 1 (FPR1)-mediated molecular imaging in a disk puncture mouse model to elucidate pathophysiological process of disk herniation.

PROCEDURES

Disk herniation was induced in mouse with an established needle puncture procedure. Degenerative change of disk and infiltration of neutrophils and macrophages were detected with Safranin-O, hematoxylin and eosin (H&E), and immunohistochemical staining after injury. FPR1-specific imaging probes cFLFLF-PEG-Cy7 and [^99mTc]HYNIC-PEG-cFLFLF were administered systemically to sham and disk injury mice. Leukocyte infiltration was tracked by in vivo near-infrared fluorescence (NIRF) and single-photon emission tomography (SPECT) imaging. The peptide-receptor binding specificity was further investigated with FPR1^-/- mice via ex vivo NIRF scan and in vitro binding assays.

RESULTS

Safranin-O staining exhibited disorganized disk structure and loss of proteoglycan after puncture. Massive inflammatory cells were observed in the anterior region of punctured annulus in the injury group. The majority of neutrophils were detected at 1 through 3 days, while infiltration of macrophages appeared the most at 7 days after injury. NIRF and SPECT images revealed preferential accumulation of cFLFLF probes in herniation site in wild-type mice but not in FPR1^-/- mice. Binding of the cFLFLF peptide to FPR1 was also observed in RAW 267.4 cells and macrophages isolated from wild-type mice, whereas much less signal was observed in macrophages from FPR1^-/- mice. The presence of macrophage infiltration was also detected in human-herniated disk samples by immunohistochemistry.

CONCLUSION

For the first time, leukocyte infiltration around acute disk herniation site was detected directly and non-invasively in a timely fashion using FPR1-targeted molecular imaging modalities. Such functional imaging of disk herniation via infiltrated leukocytes would advance the understanding of etiology and facilitate drug delivery and treatment monitoring of disk herniation.

Fluorescein Labeled Leukocytes for in vivo Imaging of Retinal Vascular Inflammation and Infiltrating Leukocytes in Laser-Induced Choroidal Neovascularization Model

Purpose: To study the effect of anti-VEGF treatment on retinal inflammation in a laser-induced CNV rodent model.Methods: Leukocytes labeled with 1% sodium fluorescein were injected into the laser-induced CNV (wild type C57BL/6) mice at days 4 (baseline), 7, 14, and 19. At baseline intravitreally 3 mice received 1× PBS, and 3 mice received anti-VEGF. FFA, OCT, and SLO were performed at each time point to assess the CNV pathophysiology and inflammatory response.Results: Fluorescein leakage, SRF, and leukocyte infiltration were observed at baseline in both the groups before injection. From days 7 to 19, leukocyte infiltration and SRF were noted in the 1× PBS group, but limited or no SRF and leukocyte infiltration was observed in the anti-VEGF group.Conclusions: Leukocyte infiltration was established as an in vivo imaging inflammatory marker and along with FFA and OCT showed response to anti-VEGF therapy in laser-induced CNV model.

Renal allograft rejection, lymphocyte infiltration, and de novo donor-specific antibodies in a novel model of non-adherence to immunosuppressive therapy

Background

Non-adherence has been associated with reduced graft survival. The aim of this study was to investigate the immunological mechanisms underlying chronic renal allograft rejection using a model of non-adherence to immunosuppressive therapy. We used a MHC (major histocompatibility complex) -mismatched rat model of renal transplantation (Brown Norway to Lewis), in which rats received daily oral cyclosporine A. In analogy to non-adherence to therapy, one group received cyclosporine A on alternating days only. Rejection was histologically graded according to the Banff classification. We quantified fibrosis by trichrome staining and intra-graft infiltration of T cells, B cells, and monocytes/macrophages by immunohistochemistry. The distribution of B lymphocytes was assessed using immunofluorescence microscopy. Intra-graft chemokine, chemokine receptor, BAFF (B cell activating factor belonging to the TNF family), and immunoglobulin G transcription levels were analysed by RT-PCR. Finally, we evaluated donor-specific antibodies (DSA) and complement-dependent cytotoxicity using flow cytometry.

Results

After 28 days, cellular rejection occurred during non-adherence in 5/6 animals, mixed with humoral rejection in 3/6 animals. After non-adherence, the number of T lymphocytes were elevated compared to daily immunosuppression. Monocyte numbers declined over time. Accordingly, lymphocyte chemokine transcription was significantly increased in the graft, as was the transcription of BAFF, BAFF receptor, and Immunoglobulin G. Donor specific antibodies were elevated in non-adherence, but did not induce complement-dependent cytotoxicity.

Conclusion

Cellular and humoral rejection, lymphocyte infiltration, and de novo DSA are induced in this model of non-adherence.

Electronic supplementary material

The online version of this article (doi: 10.1186/s12865-017-0236-6) contains supplementary material, which is available to authorized users.

TLR7-mediated skin inflammation remotely triggers chemokine expression and leukocyte accumulation in the brain

Background

The relationship between the brain and the immune system has become increasingly topical as, although it is immune-specialised, the CNS is not free from the influences of the immune system. Recent data indicate that peripheral immune stimulation can significantly affect the CNS. But the mechanisms underpinning this relationship remain unclear. The standard approach to understanding this relationship has relied on systemic immune activation using bacterial components, finding that immune mediators, such as cytokines, can have a significant effect on brain function and behaviour. More rarely have studies used disease models that are representative of human disorders.

Methods

Here we use a well-characterised animal model of psoriasis-like skin inflammation—imiquimod—to investigate the effects of tissue-specific peripheral inflammation on the brain. We used full genome array, flow cytometry analysis of immune cell infiltration, doublecortin staining for neural precursor cells and a behavioural read-out exploiting natural burrowing behaviour.

Results

We found that a number of genes are upregulated in the brain following treatment, amongst which is a subset of inflammatory chemokines (CCL3, CCL5, CCL9, CXCL10, CXCL13, CXCL16 and CCR5). Strikingly, this model induced the infiltration of a number of immune cell subsets into the brain parenchyma, including T cells, NK cells and myeloid cells, along with a reduction in neurogenesis and a suppression of burrowing activity.

Conclusions

These findings demonstrate that cutaneous, peripheral immune stimulation is associated with significant leukocyte infiltration into the brain and suggest that chemokines may be amongst the key mediators driving this response.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0562-2) contains supplementary material, which is available to authorized users.

Ethanol-Induced TLR4/NLRP3 Neuroinflammatory Response in Microglial Cells Promotes Leukocyte Infiltration Across the BBB

We reported that the ethanol-induced innate immune response by activating TLR4 signaling triggers gliosis and neuroinflammation. Ethanol also activates other immune receptors, such as NOD-like-receptors, and specifically NLRP3-inflammasome in astroglial cells, to stimulate caspase-1 cleavage and IL-1β and IL-18 cytokines production. Yet, whether microglia NLRs are also sensitive to the ethanol effects that contribute to neuroinflammation is uncertain. Using cerebral cortexes of the chronic alcohol-fed WT and TLR4(-/-) mice, we demonstrated that chronic ethanol treatment enhanced TLR4 mediated-NLRP3/Caspase-1 complex activation, and up-regulated pro-inflammatory cytokines and chemokines levels. Ethanol-induced NLRP3-inflammasome activation and mitochondria-ROS generation were also observed in cultured microglial cells. The up-regulation of CD45(high)/CD11b(+) cell populations and matrix metalloproteinase-9 levels was also noted in the cortexes of the ethanol-treated WT mice. Notably, elimination of the TLR4 function abolished most ethanol-induced neuroinflammatory effects. Thus, our results demonstrate that ethanol triggers TLR4-mediated NLRP3-inflammasome activation in glial cells, and suggest that microglia stimulation may compromise the permeability of blood-brain barrier events to contribute to ethanol-induced neuroinflammation and brain damage.

Blood-brain barrier dysfunction developed during normal aging is associated with inflammation and loss of tight junctions but not with leukocyte recruitment

Background

Functional loss of blood–brain barrier (BBB) is suggested to be pivotal to pathogenesis and pathology of vascular-based neurodegenerative disorders such as Alzheimer’s disease. We recently reported in wild-type mice maintained on standard diets, progressive deterioration of capillary function with aging concomitant with heightened neuroinflammation. However, the mice used in this study were relatively young (12 months of age) and potential mechanisms for loss of capillary integrity were not investigated per se. The current study therefore extended the previous finding to investigate the effect of aging on BBB integrity in aged mice at 24 months and its potential underlying molecular mechanisms.

Results

Immunomicroscopy analyses confirmed significantly increased capillary permeability with heightened neuroinflammation in naturally aged 24-month old mice compared to young control at 3 months of age. Aged mice showed significant attenuation in the expression of BBB tight junction proteins, occludin-1 and to lesser extent ZO-1 compared to young mice. In addition, TNF-α in cerebral endothelial cells of aged mice was significantly elevated compared to controls and this was associated with heightened peripheral inflammation. The expression of ICAM-1 and VCAM-1 remained unelevated, and no sign of leukocyte recruitment was observed in aged mice.

Conclusion

The BBB breakdown that occurs during ordinary aging is associated with inflammation and disruption of tight junction complex assembly but not through leukocyte trafficking.

Electronic supplementary material

The online version of this article (doi:10.1186/s12979-015-0029-9) contains supplementary material, which is available to authorized users.

Leukocyte infiltration as a surrogate marker for diagnosis of invasion

Dr. YG Man's hypothesis that breast tumor invasion is triggered by the aberrant leukocyte infiltration induced by degeneration of myoepithelial cells holds a lot of truth in our clinical practice, and leukocyte infiltration may be regarded as a surrogate marker for diagnosis of invasion.

Carbon liberated from CO-releasing molecules attenuates leukocyte infiltration in the small intestine of thermally injured mice

AIM: To determine whether Carbon (CO) liberated from CO-releasing molecules attenuates leukocyte infiltration in the small intestine of thermally injured mice.

METHODS: Thirty-six mice were assigned to four groups. Mice in the sham group (n = 9) were underwent to sham thermal injury; mice in the burn group (n = 9) received 15% total body surface area full-thickness thermal injury; mice in the burn + CORM-2 group (n = 9) were underwent to the same thermal injury with immediate administration of tricarbonyldichlororuthenium (II) dimer CORM-2 (8 mg/kg, i.v.); and mice in the burn+DMSO group (n = 9) were underwent to the same thermal injury with immediate administration of 160 μL bolus injection of 0.5% DMSO/saline. Histological alterations and granulocyte infiltration of the small intestine were assessed. Polymorphonuclear neutrophil (PMN) accumulation (myeloperoxidase assay) was assessed in mice mid-ileum. Activation of nuclear factor (NF)-κΒ, expression levels of intercellular adhesion molecule-1 (ICAM-1) and inducible heme oxygenase in mid-ileum were assessed.

RESULTS: Treatment of thermally injured mice with CORM-2 attenuated PMN accumulation and prevented activation of NF-κΒ in the small intestine. This was accompanied by a decrease in the expression of ICAM-1. In parallel, burn-induced granulocyte infiltration in mid-ileum was markedly decreased in the burn mice treated with CORM-2.

CONCLUSION: CORM-released CO attenuates leukocyte infiltration in the small intestine of thermally injured mice by interfering with NF-κΒ activation and protein expression of ICAM-1, and therefore suppressing the pro-adhesive phenotype of endothelial cells.