We show that an innate defense-regulator peptide (IDR-1) was protective in mouse models of infection with important Gram-positive and Gram-negative pathogens, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus and Salmonella enterica serovar Typhimurium. When given from 48 h before to 6 h after infection, the peptide was effective by both local and systemic administration. Because protection by IDR-1 was prevented by in vivo depletion of monocytes and macrophages, but not neutrophils or B- and T-lymphocytes, we conclude that monocytes and macrophages are key effector cells. IDR-1 was not directly antimicrobial: gene and protein expression analysis in human and mouse monocytes and macrophages indicated that IDR-1, acting through mitogen-activated protein kinase and other signaling pathways, enhanced the levels of monocyte chemokines while reducing pro-inflammatory cytokine responses. To our knowledge, an innate defense regulator that counters infection by selective modulation of innate immunity without obvious toxicities has not been reported previously.
Age-related macular degeneration (AMD) is the leading cause of legal blindness in the elderly in industrialized countries. AMD is a multifactorial disease influenced by both genetic and environmental risk factors. Progression of AMD is characterized by an increase in the number and size of drusen, extracellular deposits, which accumulate between the retinal pigment epithelium (RPE) and Bruch's membrane (BM) in outer retina. The major pathways associated with its pathogenesis include oxidative stress and inflammation in the early stages of AMD. Little is known about the interactions among these mechanisms that drive the transition from early to late stages of AMD, such as geographic atrophy (GA) or choroidal neovascularization (CNV). As part of the innate immune system, inflammasome activation has been identified in RPE cells and proposed to be a causal factor for RPE dysfunction and degeneration. Here, we will first review the classic model of inflammasome activation, then discuss the potentials of AMD-related factors to activate the inflammasome in both nonocular immune cells and RPE cells, and finally introduce several novel mechanisms for regulating the inflammasome activity.
Chronic inflammation is a key pathogenic process in age-related macular degeneration (AMD). Amyloid-beta (Aβ) is a constituent of AMD drusen and promotes the activation of NLRP3 inflammasome which facilitates the production of cytokines. We investigated the role of transcription factor NF-κB in the activation of inflammasome in the RPE and the effect of vinpocetine, a dietary supplement with inhibitory effect on NF-κB. ARPE19/NF-κB-luciferase reporter cells treated with Aβ demonstrated enhanced NF-κB activation that was significantly suppressed by vinpocetine. Intraperitoneal injection of vinpocetine (15 mg/kg) inhibited NF-κB nuclear translocation and reduced the expression and activation of NLRP3, caspase-1, IL-1β, IL-18, and TNF-α in the RPE of adult rats that received intraocular Aβ, as measured by retinal immunohistochemistry and Western blot. Cytokine level in the vitreous was assayed using multiplex suspension arrays and revealed significantly lower concentration of MIP-3α, IL-6, IL-1α, IL-1β, IL-18, and TNF-α in vinpocetine treated animals. These results suggest that the NF-κB pathway is activated by Aβ in the RPE and signals the priming of NLRP3 inflammasome and the expression of pro-inflammatory cytokines including the inflammasome substrates IL-1β and IL-18. NF-κB inhibition may be an effective approach to stem the chronic inflammatory milieu that underlies the development of AMD. Vinpocetine is a potentially useful anti-inflammatory agent that is well-tolerated in long term use.
The elevated systemic levels of selected proinflammatory cytokines, including those representing products of inflammasome activation, were associated with the CC at-risk variant of the Y402H polymorphism and suggest that genetic factors regulate the inflammatory status in dry AMD patients. Our data support the central role of inflammation in the pathogenesis of AMD and provide further evidence of a systemic involvement in AMD etiology.
The 5 and 3 untranslated regions (UTRs) of coxsackievirus B3 (CVB3) RNA form highly ordered secondary structures that have been confirmed to play important regulatory roles in viral cap-independent internal translation initiation and RNA replication. We previously demonstrated that deletions in different regions of the 5 UTR significantly reduced viral RNA translation and infectivity. Such observations suggested strongly that viral RNA translation and replication could be blocked if highly specific antisense oligodeoxynucleotides (AS-ODNs) were applied to target crucial sites within the 5 and 3 UTRs. In this study, seven phosphorothioate AS-ODNs were synthesized, and the antiviral activity was evaluated by Lipofectin transfection of HeLa cells with AS-ODNs followed by infection of CVB3. Analysis by Western blotting, reverse transcription-PCR, and viral plaque assay demonstrated that viral protein synthesis, genome replication, and infectivity of CVB3 were strongly inhibited by the AS-ODNs complementary to different regions of the 5 and 3 UTRs. The most effective sites are located at the proximate terminus of the 5 UTR (AS-1), the proximate terminus of the 3 UTR (AS-7), the core sequence of the internal ribosome entry site (AS-2), and the translation initiation codon region (AS-4). These AS-ODNs showed highly sequence-specific and dose-dependent inhibitory effects on both viral protein synthesis and RNA replication. It is noteworthy that the highest inhibitory activities were obtained with AS-1 and AS-7 targeting the termini of the 5 and 3 UTRs. The percent inhibition values of AS-1 and AS-7 for CVB3 protein VP1 synthesis and RNA replication were 70.6 and 79.6 for AS-1 and 73.7 and 79.7 for AS-7, respectively. These data suggest that CVB3 infectivity can be inhibited effectively by AS-ODNs.
BackgroundThe membrane attack complex (MAC) is a key player in the pathogenesis of age-related macular degeneration (AMD) and is a putative activator of the NLRP3 inflammasome. Amyloid beta (Aβ), a component of drusen deposits, has also been implicated in inflammasome activation by our work and those of others. However, the interactions of MAC and Aβ are still poorly understood, especially their roles in aging and retinal degenerative pathologies. Since inflammasome activation may represent a key cellular pathway underlying age-related chronic inflammation in the eye, the purpose of this study is to identify the effects associated with MAC and inflammasome activation in the retinal pigment epithelium (RPE)/choroid and to evaluate the therapeutic merits of MAC suppression.MethodsAdult Long-Evans rats were divided into treatment and control groups. Treatment groups received oral aurin tricarboxylic acid complex (ATAC), a MAC inhibitor, in drinking-water, and control groups received drinking-water alone (No ATAC). Groups were sacrificed at 7.5 or 11.5 months, after approximately 40 days of ATAC treatment. To study age-related changes of Aβ and MAC in RPE/choroid, naive animals were sacrificed at 2.5, 7.5, and 11.5 months. Eye tissues underwent immunohistochemistry and western blot analysis for MAC, Aβ, NF-κB activation, as well as cleaved caspase-1 and IL-18. Vitreal samples were collected and assessed by multiplex assays for secreted levels of IL-18 and IL-1β. Statistical analyses were performed, and significance level was set at p ≤ 0.05.ResultsIn vivo studies demonstrated an age-dependent increase in MAC, Aβ, and NF-κB activation in the RPE/choroid. Systemic ATAC resulted in a prominent reduction in MAC formation and a concomitant reduction in inflammasome activation measured by cleaved caspase-1 and secreted levels of IL-18 and IL-1β, but not in NF-κB activation. In vitro studies demonstrated Aβ-induced MAC formation on RPE cells.ConclusionsAge-dependent increases in Aβ and MAC are present in the rodent outer retina. Our results suggest that suppressing MAC formation and subsequent inflammasome activation in the RPE/choroid may reduce chronic low-grade inflammation associated with IL-18 and IL-1β in the outer retina.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-015-0337-1) contains supplementary material, which is available to authorized users.
Abstract-Our previous studies, using differential mRNA display, suggested that the mouse Nip21 gene may be involved in myocarditis development in the coxsackievirus B3 (CVB3)-infected mouse heart. Sequence comparison indicated that the mouse Nip21 gene shares high sequence homology to human Nip2. This human protein is known to interact with both the apoptosis inhibitor Bcl-2 and a homologous protein, the adenovirus E1B
Altered expression of TROP2 is observed in various types of human cancers. However, the clinical significance and pathological role of TROP2 in gallbladder cancer (GBC) remains unclear. The main objective of this investigation was to clarify the relationships between TROP2 expression and the clinicopathological features of patients with GBC. Immunohistochemistry was performed to investigate the expression of TROP2 and epithelial-mesenchymal transition (EMT) indicator proteins in 93 patients with GBC. Immunohistochemistry showed that the protein expression level of TROP2 was significantly higher in GBC tissues than in adjacent noncancerous tissues. In addition, immunohistochemistry analysis showed that TROP2 expression was significantly correlated with histologic grade (P=0.038), tumor stage (P=0.015), and lymph node metastasis (P=0.007). Furthermore, high TROP2 expression was significantly associated with a loss of the epithelial marker E-cadherin (P=0.013) and acquisition of expression of the mesenchymal marker vimentin (P=0.031). Kaplan-Meier analysis and Cox proportional hazards regression models were used to investigate the correlation between TROP2 expression and prognosis of GBC patients. Kaplan-Meier analysis indicated that patients with high TROP2 expression had poor overall survival (P<0.001). Multivariate analysis showed that high TROP2 expression was an independent predictor of overall survival. In conclusion, our data suggest for the first time that the increased expression of TROP2 in GBC is associated significantly with aggressive progression and poor prognosis. In conclusion, this study confirmed that TROP2 might be involved in regulating the EMT and malignant progression in GBC. It also provided the first evidence that TROP2 expression in GBC was an independent prognostic factor of patients, which might be a potential diagnostic and therapeutic target of GBC.
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