Agomelatine promotes differentiation of oligodendrocyte precursor cells and preserves white matter integrity after cerebral ischemic stroke.

White matter injury contributes to neurological disorders after acute ischemic stroke (AIS). The repair of white matter injury is dependent on the re-myelination by oligodendrocytes. Both melatonin and serotonin antagonist have been proved to protect against post-stroke white matter injury. Agomelatine (AGM) is a multi-functional treatment which is both a melatonin receptor agonist and selective serotonin receptor antagonist. Whether AGM protects against white matter injury after stroke and the underlying mechanisms remain elusive. Here, using the transient middle cerebral artery occlusion (tMCAO) model, we evaluated the therapeutic effects of AGM in stroke mice. Sensorimotor and cognitive functions, white matter integrity, oligodendroglial regeneration and re-myelination in stroke hemisphere after AGM treatment were analyzed. We found that AGM efficiently preserved white matter integrity, reduced brain tissue loss, attenuated long-term sensorimotor and cognitive deficits in tMCAO models. AGM treatment promoted OPC differentiation and enhanced re-myelination both in vitro, ex vivo and in vivo, although OPC proliferation was unaffected. Mechanistically, AGM activated low density lipoprotein receptor related protein 1 (LRP1), peroxisome proliferator-activated receptor γ (PPARγ) signaling thus promoted OPC differentiation and re-myelination after stroke. Inhibition of PPARγ or knock-down of LRP1 in OPCs reversed the beneficial effects of AGM. Altogether, our data indicate that AGM represents a novel therapy against white matter injury after cerebral ischemia.

Macrophage lineage cells-derived migrasomes activate complement-dependent blood-brain barrier damage in cerebral amyloid angiopathy mouse model.

Accumulation of amyloid beta protein (Aß) in brain vessels damages blood brain barrier (BBB) integrity in cerebral amyloid angiopathy (CAA). Macrophage lineage cells scavenge Aß and produce disease-modifying mediators. Herein, we report that Aß40-induced macrophage-derived migrasomes are sticky to blood vessels in skin biopsy samples from CAA patients and brain tissue from CAA mouse models (Tg-SwDI/B and 5xFAD mice). We show that CD5L is packed in migrasomes and docked to blood vessels, and that enrichment of CD5L impairs the resistance to complement activation. Increased migrasome-producing capacity of macrophages and membrane attack complex (MAC) in blood are associated with disease severity in both patients and Tg-SwDI/B mice. Of note, complement inhibitory treatment protects against migrasomes-mediated blood-brain barrier injury in Tg-SwDI/B mice. We thus propose that macrophage-derived migrasomes and the consequent complement activation are potential biomarkers and therapeutic targets in CAA.

Bone Marrow Mesenchymal Stem Cell-Derived Dermcidin-Containing Migrasomes enhance LC3-Associated Phagocytosis of Pulmonary Macrophages and Protect against Post-Stroke Pneumonia.

Pneumonia is one of the leading causes of death in patients with acute ischemic stroke (AIS). Antibiotics fail to improve prognosis of patients with post-stroke pneumonia, albeit suppressing infection, due to adverse impacts on the immune system. The current study reports that bone marrow mesenchymal stem cells (BM-MSC) downregulate bacterial load in the lungs of stroke mice models. RNA-sequencing of the lung from BM-MSC-treated stroke models indicates that BM-MSC modulates pulmonary macrophage activities after cerebral ischemia. Mechanistically, BM-MSC promotes the bacterial phagocytosis of pulmonary macrophages through releasing migrasomes, which are migration-dependent extracellular vesicles. With liquid chromatography-tandem mass spectrometry (LC-MS/MS), the result shows that BM-MSC are found to load the antibacterial peptide dermcidin (DCD) in migrasomes upon bacterial stimulation. Besides the antibiotic effect, DCD enhances LC3-associated phagocytosis (LAP) of macrophages, facilitating their bacterial clearance. The data demonstrate that BM-MSC is a promising therapeutic candidate against post-stroke pneumonia, with dual functions of anti-infection and immunol modulation, which is more than a match for antibiotics treatment.

FOXP3+ macrophage represses acute ischemic stroke-induced neural inflammation.

Proper termination of cell-death-induced neural inflammation is the premise of tissue repair in acute ischemic stroke (AIS). Macrophages scavenge cell corpses/debris and produce inflammatory mediators that orchestrate immune responses. Here, we report that FOXP3, the key immune-repressive transcription factor of Tregs, is conditionally expressed in macrophages in stroke lesion. FOXP3 ablation in macrophages results in detrimental stroke outcomes, emphasizing the beneficial role of FOXP3+ macrophages. FOXP3+ macrophages are distinct from the M1 or M2 subsets and display superactive efferocytic capacity. With scRNAseq and analysis of FOXP3-bound-DNA isolated with CUT & RUN, we show that FOXP3 facilitates macrophage phagocytosis through enhancing cargo metabolism. FOXP3 expression is controlled by macroautophagic/autophagic protein degradation in resting macrophages, while initiation of LC3-associated phagocytosis (LAP) competitively occupies the autophagic machineries, and thus permits FOXP3 activation. Our data demonstrate a distinct set of FOXP3+ macrophages with enhanced scavenging capability, which could be a target in immunomodulatory therapy against AIS.Abbreviations: ADGRE1/F4/80: adhesion G protein-coupled receptor E1; AIF1/Iba1: allograft inflammatory factor 1; AIS: acute ischemic stroke; ARG1: arginase 1; ATP: adenosine triphosphate; BECN1/Beclin1: Beclin 1, autophagy related; BMDM: bone marrow-derived macrophages; CKO: conditional knockout; CSF1/M-CSF: colony stimulating factor 1 (macrophage); CSF2/GM-CSF: colony stimulating factor 2; CSF3/G-CSF: colony stimulating factor 3; CUT & RUN: cleavage under targets and release using nuclease; CyD: cytochalasin D; DAMP: danger/damage-associated molecular pattern; DIL: dioctadecyl-3,3,3,3-tetramethylin docarbocyanine; ELISA: enzyme linked immunosorbent assay; GO: Gene Ontology; FCGR3/CD16: Fc receptor, IgG, low affinity III; HMGB1: high mobility group box 1; IFNG/IFNγ: interferon gamma; IP: immunoprecipitation; KEGG: Kyoto Encyclopedia of Genes and Genomes; ITGAM/CD11b: integrin subunit alpha M; ITGAX/CD11c: integrin subunit alpha X; LAP: LC3-associated phagocytosis; LC-MS: liquid chromatography-mass spectrometry; LPS: lipopolysaccharide; MRC1/CD206: mannose receptor, C type 1; O4: oligodendrocyte marker O4; PBMC: peripheral blood mononuclear cells; RBC: red blood cells; PTPRC/CD45: protein tyrosine phosphatase, receptor type, C; RBFOX3/NeuN: RNA binding protein, fox 1 homolog (C. elegans) 3; RUBCN/Rubicon: RUN domain and cysteine-rich domain containing, Beclin 1-interacting protein; scRNAseq: single cell RNA sequencing; SQSTM1/p62 (sequestosome 1); TGFB/TGFß: transforming growth factor, beta; tMCAO: transient middle cerebral artery occlusion; TNF/TNFα: tumor necrosis factor; Treg: regulatory T cell.

Melatonin Offers Dual-Phase Protection to Brain Vessel Endothelial Cells in Prolonged Cerebral Ischemia-Recanalization Through Ameliorating ER Stress and Resolving Refractory Stress Granule.

Ischemic-reperfusion injury limits the time window of recanalization therapy in cerebral acute ischemic stroke (AIS). Brain vessel endothelial cells (BVECs) form the first layer of the blood-brain barrier (BBB) and are thus the first sufferer of ischemic-reperfusion disorder. The current study demonstrates that melatonin can reduce infarct volume, alleviate brain edema, ameliorate neurological deficits, and protect BBB integrity in prolonged-stroke mice. Here, we demonstrate that endoplasmic reticulum (ER)-associated injury contributes to BVEC death in the dural phase of reperfusion after prolonged ischemia. When encountering ischemia, ER stress arises, specifically activating PERK-EIF2α signaling and the subsequent programmed cell death. Prolonged ischemia leads stress granules (SGs) to be refractory, which remain unresolved and accumulate in ER during recanalization. During reperfusion, refractory SGs activate PKR-EIF2α and further exacerbate BVEC injury. We report that melatonin treatment downregulates ER stress in the ischemic period and enhances dissociation of the refractory SGs during reperfusion, thus offering dual-phase protection to BVECs in prolonged cerebral stroke. Mechanistically, melatonin enhances autophagy in BVECs, which preserves ER function and resolves refractory SGs. We, therefore, propose that melatonin is a potential treatment to extend the time window of delayed recanalization therapy in AIS.

Hydroxocobalamin: An Effective Treatment for Flushing and Persistent Erythema in Rosacea.

Background: Expression of inducible nitric oxide synthase (NOS) is higher in rosacea skin samples than in normal skin controls. Hydroxocobalamin is a potent inhibitor of all isoforms of NOS, capable of reducing the vasodilatations induced by nitric oxide. Objective: We aimed to evaluate the role of hydroxocobalamin in treating facial flushing and persistent erythema of rosacea. Methods: Thirteen patients with rosacea who displayed facial flushing and persistent erythema received 1 to 4 weekly intramuscular injections of hydroxocobalamin 1 to 2 mg. The outcomes were measured using the Clinician's Erythema Assessment (CEA) by photography and an infrared thermometer to evaluate the difference in skin surface temperature (SST) of the cheeks before and after treatment. Results: Thirty minutes after the first dose of intramuscular injection of hydroxocobalamin, the mean CEA significantly reduced from 2.2± 0.6 to 1.2±0.4 (p<0.001), and average SST also significantly reduced from 36.7±0.70°C to 36.2±0.61°C (p<0.001) on the cheeks. Conclusion: In our patient sample, intramuscular administration of hydroxocobalamin was effective for immediate reduction of facial erythema associated with rosacea.

Rosacea with persistent facial erythema and high Demodex density effectively treated with topical ivermectin alone or combined with oral carvedilol.

Topical ivermectin is effective in treating papulopustular rosacea, but its effect on persistent facial erythema of rosacea with high Demodex densities has not been well documented. We retrospectively reviewed 39 rosacea patients with persistent facial erythema and high Demodex densities. Clinician's erythema assessment (CEA) and Demodex density were evaluated before and after topical ivermectin alone or combined with oral carvedilol. Three patients (all with papulopustular rosacea, in ivermectin group) dropped out due to early ivermectin-induced local flare of rosacea. In the remaining patients (ivermectin group n = 14; ivermectin-carvedilol group n = 22), the CEA grade and Demodex density were significantly reduced, both P < .01. There was no statistically significant difference between the two groups in CEA before and after treatment (P = .07 and P = .23, respectively), and in Demodex density (P = .82 and .10, respectively). Both regimens markedly improved the persistent facial erythema with response being excellent in 26 of 36 patients (72%), good in 2, fair in 4 and none in 4. There was a correlation between the reduction of CEA and Demodex density after treatment (rho = 0.50, P = .002). The results showed that topical ivermectin was effective in reducing persistent facial erythema of rosacea with Demodex overgrowth.

A new superficial needle-scraping method for assessing Demodex density in papulopustular rosacea.

BACKGROUND: Standardized skin surface biopsy (SSSB) is often performed to determine the density of Demodex mites in facial papulopustular eruptions. AIM: We aimed to test the applicability of a new, "superficial needle-scraping" (SNS) method for assessing Demodex density in papulopustular rosacea (PPR). PATIENTS AND METHODS: Using SNS method, we measured the Demodex density in patients with PPR, also enrolling the patients with acne vulgaris as controls. SNS was performed by gently scraping off 5 small pustules with the convex surface of the tip of an 18# needle for examination. For comparison, SSSB was also performed in patients with PPR. Demodex density was expressed as "mites per 5 pustules" for SNS and as "mites per cm2 " for SSSB. RESULTS: A total of 40 patients with PPR and 35 patients with acne vulgaris were recruited. There were no statistically significant differences in age or sex between the PPR and acne groups. The Demodex density was 5.6 ± 4.2 in the PPR group versus 0.3 ± 1.0 in the acne group (P < .001). The cutoff of "≥3 Demodex mites per 5 pustules" gave a sensitivity of 78% and a specificity of 97%, and the area under the receiver operating characteristic curve was 0.89. Moreover, SNS and SSSB gave mutually concordant results (positive or negative) in half of the patients. CONCLUSION: Our study suggests that SNS is a simple and convenient method for assessing Demodex density of pustules in PPR and can be a useful alternative or addition to SSSB for evaluation of Demodex-associated facial papulopustular eruptions.

Role of neuromedin B and its receptor in the innate immune responses against influenza A virus infection in vitro and in vivo.

The peptide neuromedin B (NMB) and its receptor (NMBR) represent a system (NMB/NMBR) of neuromodulation. Here, it was demonstrated that the expression of NMBR in cells or murine lung tissues was clearly upregulated in response to H1N1/PR8 influenza A virus infection. Furthermore, the in vitro and in vivo activities of NMB/NMBR during PR8 infection were investigated. It was observed that A549 cells lacking endogenous NMBR were more susceptible to virus infection than control cells, as evidenced by the increased virus production in the cells. Interestingly, a significant decrease in IFN-α and increased IL-6 expression were observed in these cells. The role of this system in innate immunity against PR8 infection was probed by treating mice with NMB. The NMB-treated mice were less susceptible to virus challenge, as evidenced by increased survival, increased body weight, and decreased viral NP expression compared with the control animals. Additionally, the results showed that exogenous NMB not only enhanced IFN-α expression but also appeared to inhibit the expression of NP and IL-6 in PR8-infected cells and animals. As expected, opposing effects were observed in the NMBR antagonist-treated cells and mice, which further confirmed the effects of NMB. Together, these data suggest that NMB/NMBR may be an important component of the host defence against influenza A virus infection. Thus, these proteins may serve as promising candidates for the development of novel antiviral drugs.