Induction of Siglec-G by RNA viruses inhibits the innate immune response by promoting RIG-I degradation.

RIG-I is a critical RNA virus sensor that serves to initiate antiviral innate immunity. However, posttranslational regulation of RIG-I signaling remains to be fully understood. We report here that RNA viruses, but not DNA viruses or bacteria, specifically upregulate lectin family member Siglecg expression in macrophages by RIG-I- or NF-κB-dependent mechanisms. Siglec-G-induced recruitment of SHP2 and the E3 ubiquitin ligase c-Cbl to RIG-I leads to RIG-I degradation via K48-linked ubiquitination at Lys813 by c-Cbl. By increasing type I interferon production, targeted inactivation of Siglecg protects mice against lethal RNA virus infection. Taken together, our data reveal a negative feedback loop of RIG-I signaling and identify a Siglec-G-mediated immune evasion pathway exploited by RNA viruses with implication in antiviral applications. These findings also provide insights into the functions and crosstalk of Siglec-G, a known adaptive response regulator, in innate immunity.

A new era of cancer immunotherapy: combining revolutionary technologies for enhanced CAR-M therapy.

Significant advancements have been made in the application of chimeric antigen receptor (CAR)-T treatment for blood cancers during the previous ten years. However, its effectiveness in treating solid tumors is still lacking, necessitating the exploration of alternative immunotherapies that can overcome the significant challenges faced by current CAR-T cells. CAR-based immunotherapy against solid tumors shows promise with the emergence of macrophages, which possess robust phagocytic abilities, antigen-presenting functions, and the ability to modify the tumor microenvironment and stimulate adaptive responses. This paper presents a thorough examination of the latest progress in CAR-M therapy, covering both basic scientific studies and clinical trials. This study examines the primary obstacles hindering the realization of the complete potential of CAR-M therapy, as well as the potential strategies that can be employed to overcome these hurdles. With the emergence of revolutionary technologies like in situ genetic modification, synthetic biology techniques, and biomaterial-supported gene transfer, which provide a wider array of resources for manipulating tumor-associated macrophages, we suggest that combining these advanced methods will result in the creation of a new era of CAR-M therapy that demonstrates improved efficacy, safety, and availability.

Nanomaterials-assisted gene editing and synthetic biology for optimizing the treatment of pulmonary diseases.

The use of nanomaterials in gene editing and synthetic biology has emerged as a pivotal strategy in the pursuit of refined treatment methodologies for pulmonary disorders. This review discusses the utilization of nanomaterial-assisted gene editing tools and synthetic biology techniques to promote the development of more precise and efficient treatments for pulmonary diseases. First, we briefly outline the characterization of the respiratory system and succinctly describe the principal applications of diverse nanomaterials in lung ailment treatment. Second, we elaborate on gene-editing tools, their configurations, and assorted delivery methods, while delving into the present state of nanomaterial-facilitated gene-editing interventions for a spectrum of pulmonary diseases. Subsequently, we briefly expound on synthetic biology and its deployment in biomedicine, focusing on research advances in the diagnosis and treatment of pulmonary conditions against the backdrop of the coronavirus disease 2019 pandemic. Finally, we summarize the extant lacunae in current research and delineate prospects for advancement in this domain. This holistic approach augments the development of pioneering solutions in lung disease treatment, thereby endowing patients with more efficacious and personalized therapeutic alternatives.

Modulation of alveolar macrophage and mitochondrial fitness by medicinal plant-derived nanovesicles to mitigate acute lung injury and viral pneumonia.

Acute lung injury (ALI) is generally caused by severe respiratory infection and characterized by overexuberant inflammatory responses and inefficient pathogens-containing, the two major processes wherein alveolar macrophages (AMs) play a central role. Dysfunctional mitochondria have been linked with distorted macrophages and hence lung disorders, but few treatments are currently available to correct these defects. Plant-derive nanovesicles have gained significant attention because of their therapeutic potential, but the targeting cells and the underlying mechanism remain elusive. We herein prepared the nanovesicles from Artemisia annua, a well-known medicinal plant with multiple attributes involving anti-inflammatory, anti-infection, and metabolism-regulating properties. By applying three mice models of acute lung injury caused by bacterial endotoxin, influenza A virus (IAV) and SARS-CoV-2 pseudovirus respectively, we showed that Artemisia-derived nanovesicles (ADNVs) substantially alleviated lung immunopathology and raised the survival rate of challenged mice. Macrophage depletion and adoptive transfer studies confirmed the requirement of AMs for ADNVs effects. We identified that gamma-aminobutyric acid (GABA) enclosed in the vesicles is a major molecular effector mediating the regulatory roles of ADNVs. Specifically, GABA acts on macrophages through GABA receptors, promoting mitochondrial gene programming and bioenergy generation, reducing oxidative stress and inflammatory signals, thereby enhancing the adaptability of AMs to inflammation resolution. Collectively, this study identifies a promising nanotherapeutics for alleviating lung pathology, and elucidates a mechanism whereby the canonical neurotransmitter modifies AMs and mitochondria to resume tissue homeostasis, which may have broader implications for treating critical pulmonary diseases such as COVID-19.

Imazalil resulted in glucolipid metabolism disturbance and abnormal m6A RNA methylation in the liver of dam and offspring mice.

As a fungicide with the characteristics of high effectiveness, internal absorption and broad spectrum, imazalil is widely used to prevent and treat in fruits and vegetables. Here, pregnant C57BL/6 mice were exposed to imazalil at dietary levels of 0, 0.025‰, and 0.25‰ through drinking water during pregnancy and lactation. We then analyzed the phenotype, metabolome, and expression of related genes and proteins in the livers of mice. There was a marked decrease in the body and liver weights of male offspring mice after maternal imazalil exposure, while this effect on the dam and female offspring was slight. Metabolomics analyses revealed that imazalil significantly altered the metabolite composition of liver samples from both dams and offspring. The preliminary results of the analysis indicated that glucolipid metabolism was the pathway most significantly affected by imazalil. We performed a coabundance association analysis of metabolites with significant changes in the pathway of glycolipid metabolism, and IMZ altered the networks of both dams and offspring compared with the network in control mice, especially in male offspring. The hepatic triglyceride, non-esterified fatty acid and glucose levels were increased significantly in the dams but decreased significantly in male offspring after maternal imazalil exposure. Furthermore, the expression levels of genes associated with glycolipid metabolism and m6A RNA methylation were significantly affected by maternal intake of imazalil. Imazalil-induced glucolipid metabolism disturbance was highly correlated with m6A RNA methylation. In conclusion, maternal imazalil exposure resulted in glucolipid metabolism disturbance and abnormal m6A RNA methylation in the livers of dams and offspring mice. We expected that the information acquired in this study will provide novel evidence for understanding the effect of maternal imazalil exposure on potential health risks.

Medicinal plant-derived mtDNA via nanovesicles induces the cGAS-STING pathway to remold tumor-associated macrophages for tumor regression.

Plant-derived nanovesicles (PDNVs) have been proposed as a major mechanism for the inter-kingdom interaction and communication, but the effector components enclosed in the vesicles and the mechanisms involved are largely unknown. The plant Artemisia annua is known as an anti-malaria agent that also exhibits a wide range of biological activities including the immunoregulatory and anti-tumor properties with the mechanisms to be further addressed. Here, we isolated and purified the exosome-like particles from A. annua, which were characterized by nano-scaled and membrane-bound shape and hence termed artemisia-derived nanovesicles (ADNVs). Remarkably, the vesicles demonstrated to inhibit tumor growth and boost anti-tumor immunity in a mouse model of lung cancer, primarily through remolding the tumor microenvironment and reprogramming tumor-associated macrophages (TAMs). We identified plant-derived mitochondrial DNA (mtDNA), upon internalized into TAMs via the vesicles, as a major effector molecule to induce the cGAS-STING pathway driving the shift of pro-tumor macrophages to anti-tumor phenotype. Furthermore, our data showed that administration of ADNVs greatly improved the efficacy of PD-L1 inhibitor, a prototypic immune checkpoint inhibitor, in tumor-bearing mice. Together, the present study, for the first time, to our knowledge, unravels an inter-kingdom interaction wherein the medical plant-derived mtDNA, via the nanovesicles, induces the immunostimulatory signaling in mammalian immune cells for resetting anti-tumor immunity and promoting tumor eradication.

Bcl6 drives stem-like memory macrophages differentiation to foster tumor progression.

Cancer development is a long-lasting process during which macrophages play a pivotal role. However, how macrophages maintain their cellular identity, persistence, expanding and pro-tumor property during malignant progression remains elusive. Inspired by the recent report of the activation of stem cell-like self-renewal mechanism in mature macrophages, we postulate that intra-tumoral macrophages might be trained to assume stem-like properties and memory-like activity favoring cancer development. Herein we demonstrated that tumor infiltrating macrophages rapidly converted into the CD11b+F4/80+Ly6C-Bcl6+ phenotype, and adopted stem cell-like properties involving expression of stemness-related genes, long-term persistence and self-renewing. Importantly, Bcl6+ macrophages stably maintained cell identity, gene signature, metabolic profile, and pro-tumor property even after long-term culture in tumor-free medium, which were hence termed stem cell-like memory macrophages (SMMs). Mechanistically, we showed that transcriptional factor Bcl6 co-opted the demethylase Tet2 and the deacetylase SIRT1 to confer the epigenetic imprinting and mitochondrial metabolic traits to SMMs, bolstering the stability and longevity of trained immunity in tumor-associated macrophages (TAMs). Furthermore, tumor-derived redHMGB1 was identified as the priming signal, which, through TLR4 and mTOR/AKT pathway, induced Bcl6-driven program underpinning SMMs generation. Collectively, our study uncovers a distinct macrophage population with a hybrid of stem cell and memory cell properties, and unveils a regulatory mechanism that integrates transcriptional, epigenetic and metabolic pathways to promote long-lasting pro-tumor immunity.

Transcriptome Landscape Analyses of the Regulatory Network for Zygotic Embryo Development in Paeonia ostii.

Paeonia ostii is a worldwide ornamental flower and an emerging oil crop. Zyotic embryogenesis is a critical process during seed development, and it can provide a basis for improving the efficiency of somatic embryogenesis (SE). In this study, transcriptome sequencing of embryo development was performed to investigate gene expression profiling in P. ostii and identified Differentially expressed genes (DEGs) related to transcription factors, plant hormones, and antioxidant enzymes. The results indicated that IAA (Indole-3-acetic acid), GA (Gibberellin), BR (Brassinosteroid) and ETH (Ethylene) were beneficial to early embryonic morphogenesis, while CTK (Cytokinin) and ABA (Abscisic Acid) promoted embryo morphogenesis and maturation. The antioxidant enzymes' activity was the highest in early embryos and an important participant in embryo formation. The high expression of the genes encoding fatty acid desaturase was beneficial to fast oil accumulation. Representative DEGs were selected and validated using qRT-PCR. Protein-protein interaction network (PPI) was predicted, and six central node proteins, including AUX1, PIN1, ARF6, LAX3, ABCB19, PIF3, and PIF4, were screened. Our results provided new insights into the formation of embryo development and even somatic embryo development in tree peonies.

[Rosmarinic acid bolsters antibacterial immunity activity of macrophages by up-regulating PINK1/Parkin-mediated mitophagy].

This study aims to explore the molecular mechanism through which rosmarinic acid up-regulates mitophagy and enhances antibacterial immunity activity of macrophages. To be specific, RAW264.7 macrophages were treated with rosmarinic acid and then infected with Staphylococcus aureus. The total mRNA and proteins of the cells were then extracted. The mRNA and protein levels of phosphatase and tensin homolog(PTEN)-induced putative kinase 1(PINK1) were detected by q-PCR and Western blot, respectively. Cell mitochondria isolation kit was employed to isolate mitochondria in macrophages. Recruitment of E3 ubiquitin ligase Parkin to mitochondria and the phosphorylation of Parkin were detected by Western blot. Co-immunoprecipitation and laser confocal microscopy were employed to observe the co-localization of PINK1 and Parkin. Mitochondrial division inhibitor 1(Mdivi-1), small interfering RNA(siRNA)-directed gene knockdown, and plate-colony counting were used to detect the levels of inflammatory cytokines and the intracellular antibacterial ability, in an attempt to confirm that rosmarinic acid promotes antibacterial immunity activity of macrophages through strengthening PINK1/Parkin-mediated mitophagy. The results showed that rosmarinic acid up-regulated the mRNA and protein expression of PINK1, promoted the recruitment of Parkin from cytoplasm to mitochondria and the phosphorylation, and enhanced the interaction between PINK1 and Parkin and their co-localization in macrophages. Blocking mitophagy or knocking PINK1 significantly abrogated the promotion of macrophage antibacterial immune response by rosmarinic acid. In summary, rosmarinic acid enhances antibacterial immunity activity of macrophages through up-regulating PINK1/Parkin-mediated mitophagy.

Daphnetin ameliorates experimental colitis by modulating microbiota composition and Treg/Th17 balance.

Inflammatory bowel diseases (IBDs) are characterized by chronic pathologies associated with extensive gut dysbiosis and intestinal inflammation. Hence, endeavors to improve the inflammatory pathology by manipulating gut microbiota are ongoing. Daphnetin (DAPH) is a coumarin derivative extracted from Daphne odora var with anti-inflammatory and immune-regulatory properties that has been widely used in treating inflammatory disorders. Herein, we showed that DAPH remarkably alleviated experimental colitis by reducing colonic inflammation, improving colonic integrity, and reestablishing immune and metabolic homeostasis in the inflicted intestines. Our analysis showed that DAPH modified the composition of gut microbiota and altered the metabolic profiles in dextran sulfate sodium-treated mice. In particular, this agent significantly elevated the abundance of short-chain fatty acid (SCFA)-producing gut microbiota, causatively related with the enhanced development of Treg cells and the reduced proinflammatory Th17 cell differentiation. More critically, the protective effect of DAPH was shown to be transmissible among colitic mice through cohousing or fecal microbiota transplantation, further substantiating the importance of SCFA-producing gut microbiota in DAPH action. We thus for the first time reveal the potential of DAPH in resetting the gut microbiome and reestablishing immune homeostasis in colitic mice, which may have clinical implications for treating IBD.-Ji, J., Ge, X., Chen, Y., Zhu, B., Wu, Q., Zhang, J., Shan, J., Cheng, H., Shi, L. Daphnetin ameliorates experimental colitis by modulating microbiota composition and Treg/Th17 balance.

Daphnetin Ameliorates Experimental Autoimmune Encephalomyelitis Through Regulating Heme Oxygenase-1.

To assess the potential role of daphnetin, a clinically used anti-inflammatory agent, on the development of the inflammatory and neurodegenerative disease, we investigated its immune regulatory function in a murine model of experimental autoimmune encephalomyelitis (EAE). Significantly, lower levels of pro-inflammatory cytokines including interleukin (IL)-17, interferon-γ, Il6, Il12a, and Il23a were observed in brains of daphnetin-treated EAE mice, compared with those in control littermates. We also confirmed that daphnetin suppressed the production of IL-1ß, IL-6, and tumor necrosis factor-α in lipopolysaccharide-stimulated mouse BV2 microglial cells. Mechanistically, heme oxygenase-1 (HO-1), a canonical anti-oxidant and anti-inflammatory factor, was found to be substantially induced by daphnetin treatment in BV2 cells. Also, a significantly higher level of HO-1, accompanied by a decreased level of malondialdehyde, was observed in daphnetin-treated EAE mice. More importantly, the deletion of HO-1 in BV2 microglia largely abrogated daphnetin-mediated inhibition of the inflammatory response. Together, our data demonstrate that daphnetin has an anti-inflammatory and neuroprotective role during the pathogenesis of EAE, which is partially at least, dependent on its regulation of HO-1.

Microbial biomarkers of common tongue coatings in patients with gastric cancer.

PURPOSE: The study aims to explore the characteristic microorganisms of the common tongue coatings in patients with gastric cancer (GC). METHODS: A total of 115 GC patients were assigned to four groups: White-thin coating (W-thin) group, White-thick coating (W-thick) group, Yellow-thin coating (Y-thin) group and Yellow-thick coating (Y-thick) group. Thirty-five healthy volunteers with White-thin coating were recruit as controls. High-throughput sequencing was used to describe the microbial community of the tongue coatings based on 16S rRNA and 18S rRNA genes. Multi-factors statistical analysis was carried out to present the microbial biomarkers of the tongue coating in GC patients. RESULTS: At bacterial phylum level, Saccharibacteria had higher relative abundance in W-thick group than W-thin group, Proteobacteria was more abundant in W-thin group than Y-thick group and less abundant in Y-thick group than Y-thin group. At fungal genus level, Guehomyces and Aspergillus presented to be significantly different among the common tongue coatings. Forteen significantly increased taxa were sorted out as the microbial biomarkers of common tongue coatings by LEfSe and ROC analysis. At species level, bacterial Capnocytophaga leadbetteri and fungal Ampelomyces_sp_IRAN_1 may be the potential biomarkers of W-thin coating, four bacterial species (Megasphaera micronuciformis, Selenomonas sputigena ATCC 35185, Acinetobacter ursingii, Prevotella maculosa) may be the potential biomarkers of W-thick coating. In general, the white coatings held more complex commensal relationship than the yellow coatings. CONCLUSION: The common tongue coating owned characteristic microorganisms and special commensal relationship in the GC patients.

CD200 Modulates S. aureus-Induced Innate Immune Responses Through Suppressing p38 Signaling.

Rapid activation of macrophages plays a central role in eliminating invading bacteria as well as in triggering the inflammatory responses, but how the anti-bacterial and the inflammatory responses are coordinated, in terms of macrophages, is not completely understood. In this study, we demonstrated that Staphylococcus aureus (S. aureus) induced the expression of CD200 in murine macrophages in a dose-dependent manner. We found that CD200 significantly suppressed the S. aureus-induced production of nitric oxide and proinflammatory cytokines in mouse macrophages. Concurrently, the bactericidal capability of macrophages was boosted upon the deletion of CD200. Furthermore, our data demonstrated that p38 mitogen-activated protein kinase (MAPK) was selectively down-regulated by CD200 administration, while enhanced upon CD200 silence in response to staphylococcal infection. The negative effect of CD200 siRNA on NO production in macrophages was largely abrogated upon the inhibition of p38 signaling, implying its critical involvement in this regulation. Together, our data demonstrate that CD200 plays a central role in regulating the inflammatory responses and the anti-bacterial activity of macrophages, at least partially, through suppressing p38 activity.

Understanding immune phenotypes in human gastric disease tissues by multiplexed immunohistochemistry.

BACKGROUND: Understanding immune phenotypes and human gastric disease in situ requires an approach that leverages multiplexed immunohistochemistry (mIHC) with multispectral imaging to facilitate precise image analyses. METHODS: We developed a novel 4-color mIHC assay based on tyramide signal amplification that allowed us to reliably interrogate immunologic checkpoints, including programmed death-ligand 1 (PD-L1), cytotoxic T cells (CD8+T) and regulatory T cells (Foxp3), in formalin-fixed, paraffin-embedded tissues of various human gastric diseases. By observing cell phenotypes within the disease tissue microenvironment, we were able to determine specific co-localized staining combinations and various measures of cell density. RESULTS: We found that PD-L1 was expressed in gastric ulcer and in tumor cells (TCs), as well as in tumor-infiltrating immune cells (TIICs), but not in normal gastric mucosa or other gastric intraepithelial neoplastic tissues. Furthermore, we found no significant reduction in CD8+T cells, whereas the ratio of CD8+T:Foxp3 cells and CD8+T:PD-L1 cells was suppressed in tumor tissues and elevated in adjacent normal tissues. An unsupervised hierarchical analysis also identified correlations between CD8+T and Foxp3+ tumor-infiltrating lymphocyte (TIL) densities and average PD-L1 levels. Three main groups were identified based on the results of CD8+T:PD-L1 ratios in gastric tumor tissues. Furthermore, integrating CD8+T:Foxp3 ratios, which increased the complexity for immune phenotype status, revealed 6-7 clusters that enabled the separation of gastric cancer patients at the same clinical stage into different risk-group subsets. CONCLUSIONS: Characterizing immune phenotypes in human gastric disease tissues via multiplexed immunohistochemistry may help guide PD-L1 clinical therapy. Observing unique disease tissue microenvironments can improve our understanding of immune phenotypes and cell interactions within these microenvironments, providing the ability to predict safe responses to immunotherapies.

Protective Role of Adipose-Derived Stem Cells in Staphylococcus aureus-Induced Lung Injury is Mediated by RegIIIγ Secretion.

Effective and specific therapeutic approaches are still needed for treating acute lung injury caused by severe pneumonia. Adipose-derived stem cells (ADSCs) are well-characterized adult stem cells that have antibacterial and anti-inflammatory effects. In this study, we evaluated the therapeutic effect of ADSCs on Staphylococcus aureus-induced acute lung injury in mice. Our results showed that intratracheal injection of ADSCs could attenuate the severity of lung inflammation, and reduce the bacterial load as well as mortality among infected mice. Our experiments also revealed that the secretion of regenerating islet-derived IIIγ (RegIIIγ) is responsible for the protective effect of ADSCs. Moreover, the expression of RegIIIγ requires TLR2, MyD88, and JAK2/STAT3 activation. In conclusion, ADSCs exhibit a direct antimicrobial activity that is mediated primarily by the TLR2-MyD88-JAK2/STAT3-dependent secretion of RegIIIγ. Stem Cells 2016;34:1947-1956.

Interleukin-1ß impedes oligodendrocyte progenitor cell recruitment and white matter repair following chronic cerebral hypoperfusion.

Subcortical ischemic vascular dementia (SIVD) caused by chronic cerebral hypoperfusion exhibits progressive white matter and cognitive impairments. However, its pathogenetic mechanisms are poorly understood. We investigated the role of interleukin-1ß (IL-1ß) and its receptor IL-1 receptor type 1 (IL-1R1) in an experimental SIVD model generated via right unilateral common carotid arteries occlusion (rUCCAO) in mice. We found that IL-1ß expression was elevated in the corpus callosum at the early stages after rUCCAO. IL-1 receptor antagonist (IL-1Ra), when delivered at an early stage, as well as IL-1R1 knockout, rescued the downregulation of myelin basic protein (MBP) and improved remyelination at the later stage after rUCCAO. Our data suggest that the recruitment of OPCs, but not the proliferation or differentiation of OPCs, is the only compromised step of remyelination following chronic cerebral ischemia. IL-1Ra treatment and IL-1R1 knockout had no effect on the oligodendrocyte progenitor cell (OPC) proliferation, but did promote the recruitment of newly generated OPCs to the corpus callosum, which can be reversed by compensatory expression of IL-1R1 in the SVZ of IL-1R1 knockout mice. Further, we found that recruited OPCs contribute to oligodendrocyte regeneration and functional recovery. In transwell assays, IL-1ß inhibited OPC migration through IL-1R1. Moreover, KdPT which can enter the brain to block IL-1R1 also showed comparable protection when intraperitoneally delivered. Our results suggest that IL-1ß during the early stages following chronic cerebral hypoperfusion impedes OPC recruitment via IL-1R1, which inhibits white matter repair and functional recovery. IL-1R1 inhibitors may have potential uses in the treatment of SIVD.

MiR-127 modulates macrophage polarization and promotes lung inflammation and injury by activating the JNK pathway.

A polarized macrophage response is presumed to have a pivotal role in a variety of immunological pathophysiology. However, the molecular mechanism underlying macrophage functional shaping remains largely unknown. In this study, we reveal a pivotal role of miR-127 in macrophage development and thereby the pathogenesis of inflammation and lung injury. In particular, miR-127 was demonstrated to be prominently induced upon TLR engagement and repressed by the M2-prone cytokines. Enforced expression of miR-127 in macrophages resulted in significantly increased production of proinflammatory cytokines, whereas deletion of miR-127 impaired M1 gene expression and led to a M2-biased response. Accordingly, intratracheal administration of miR-127 resulted in an exaggerated pulmonary inflammation and injury. Conversely, antagonizing of miR-127 suppressed production of the proinflammatory cytokines and rendered the mice more refractory to the inflammation-associated pathology. Mechanistically, miR-127 demonstrated to target B cell lymphoma 6 (Bcl6) and remarkably downregulated its expression and subsequently dual specificity phosphatase 1 (Dusp1), which in turn enhanced the activation of JNK kinase and hence the development of proinflammatory macrophages. Thereby, reconstitution with the expression of Bcl6 or Dusp1 or inhibition of JNK activity impaired miR-127-mediated skewing of M1 proinflammatory macrophages, whereas interference of Bcl6 or Dusp1 expression abrogated the anti-inflammatory property of anti-miR-127. Together, these data establish miR-127 as a molecular switch during macrophage development and as a potential target for treatment of inflammatory diseases.

Reduced neurotrophic factor level is the early event before the functional neuronal deficiency in high-fat diet induced obese mice.

Neurodegeneration is considered one of the possible complications of high fat diet (HFD) induced obesity. Much evidence has shown the close relationship between HFD and dementia at comparatively later stage of neuronal injury. It is so far not clear that the initial events of neuronal injury resulting from HFD and obesity. In the present research, obese mouse model achieved by 3-month HFD was applied for the investigation of the possible neuronal deficiency before the obvious cognitive decline. We found that 3-month HFD has already increased the average level of body weight of mice. But almost no obvious cognitive defect was observed. At such time point, we detected the cleavage of amyloid precursor protein (APP), including the expression and maturation level of α- and ß-secretase and proteolytic fragment soluble APP. Results showed similar readout between HFD and normal diet (ND) mice. Besides, neuronal inflammation and brain-blood barrier permeability were also detected. No obvious changes could be observed between HFD and ND mice. Surprisingly, the first detectable neuronal changes was showed to be the downregulation of some neurotrpic factors, like neuronal growth factor ß and brain derived neurotrophic factor, together with the activity of specific receptors, like Trk receptor phosphorylation. All the data piled up indicated that the early neuronal change in HFD induced obese mice was the downregulation of some neurotrophic factors. The results may provide the potential clue to therapeutic and preventive strategy for HFD induced cognitive decline.

MiR-221 activates the NF-κB pathway by targeting A20.

MicroRNAs play an important role in regulating the inflammatory response, and are critically involved in the development of inflammatory disorders, including those affecting the lungs. While the microRNA miR-221 is involved in embryonic lung branching morphogenesis and epithelial cell development, its importance in lung inflammation has not been previously explored. In our current study, expression of miR-221 was selectively decreased by exposure to lipopolysaccharides (LPS) both in vitro and in vivo. Enforced expression of miR-221 significantly increased the production of proinflammatory cytokines TNF-α and IL-6, and enhanced the activation of NF-κB and MAPKs upon LPS stimulation. Accordingly, intratracheal stimulation of miR-221 was shown to aggravate endotoxin-induced acute lung injuries and inflammation in mice. Mechanistic studies showed that miR-221 directly targets A20, a master regulator of NF-κB and MAPK signaling, and thus represses inflammatory signaling. Restoration of A20 in macrophages abolished the stimulatory effect of miR-221 on production of proinflammatory cytokines. Together, these results indicate the presence of a novel miRNA-mediated feed-back mechanism that controls inflammation, and suggest involvement of aberrant miR-221 expression in the development of inflammatory lung disorders.

A critical time window for the analgesic effect of central histamine in the partial sciatic ligation model of neuropathic pain.

BACKGROUND: It is known that histamine participates in pain modulation. However, the effect of central histamine on neuropathic pain is not fully understood. Here, we report a critical time window for the analgesic effect of central histamine in the partial sciatic nerve ligation model of neuropathic pain. METHODS: Neuropathic pain was induced by partial sciatic nerve ligation (PSL) in rats, wild-type (C57BL/6J) mice and HDC(-/-) (histidine decarboxylase gene knockout) and IL-1R(-/-) (interleukin-1 receptor gene knockout) mice. Histidine, a precursor of histamine that can increase the central histamine levels, was administered intraperitoneally (i.p.). Histidine decarboxylase (HDC) enzyme inhibitor α-fluoromethylhistidine was administered intracerebroventricularly (i.c.v.). Histamine H1 receptor antagonist mepyramine and H2 receptor antagonist cimetidine were given intrathecally (i.t.) and intracisternally (i.c.). Withdrawal thresholds to tactile and heat stimuli were measured with a set of von Frey hairs and infrared laser, respectively. Immunohistochemistry and Western blot were carried out to evaluate the morphology of microglia and IL-1ß production, respectively. RESULTS: Histidine (100 mg/kg, i.p.) administered throughout days 0-3, 0-7, or 0-14 postoperatively (PO) alleviated mechanical allodynia and thermal hyperalgesia in the hindpaw following PSL in rats. Intrathecal histamine reversed PSL-induced thermal hyperalgesia in a dose-dependent manner and intracisternal histamine alleviated both mechanical allodynia and thermal hyperalgesia. Moreover, α-fluoromethylhistidine (i.c.v.) abrogated the analgesic effect of histidine. However, histidine treatment initiated later than the first postoperative day (treatment periods included days 2-3, 4-7, and 8-14 PO) did not show an analgesic effect. In addition, histidine treatment initiated immediately, but not 3 days after PSL, inhibited microglial activation and IL-1ß upregulation in the lumbar spinal cord, in parallel with its effects on behavioral hypersensitivity. Moreover, the inhibitory effects on pain hypersensitivity and spinal microglial activation were absent in HDC(-/-) mice and IL-1R(-/-) mice. H1 receptor antagonist mepyramine (200 ng/rat i.t. or i.c.), but not H2 receptor antagonist cimetidine (200, 500 ng/rat i.t. or 500 ng/rat i.c.), blocked the effects of histidine on pain behavior and spinal microglia. CONCLUSIONS: These results demonstrate that central histamine is analgesic within a critical time window in the PSL model of neuropathic pain via histamine H1 receptors. This effect may partly relate to the inhibition of microglial activation and IL-1ß production in the spinal cord following nerve injury.