Interleukin-1β Converting Enzyme Research Articles

RNA-Seq Reveals Transcriptome Changes Following Zika Virus Infection in Fetal Brains in c-Flip Knockdown Mice.

The FADD-like interleukin-1β converting enzyme (FLICE)-inhibitory protein (c-FLIP) plays a crucial role in various biological processes, including apoptosis and inflammation. However, the complete transcriptional profile altered by the c-FLIP is not fully understood. Furthermore, the impact of the c-FLIP deficiency on the transcriptome during a Zika virus (ZIKV) infection, which induces apoptosis and inflammation in the central nervous system (CNS), has not yet been elucidated. In this study, we compared transcriptome profiles between wild-type (WT) and the c-Flip heterozygous knockout mice (c-Flip+/-) fetal heads at embryonic day 13.5 from control and PBS-infected WT dams mated with c-Flip+/- sires. In the non-infected group, we observed differentially expressed genes (DEGs) mainly involved in embryonic development and neuron development. However, the ZIKV infection significantly altered the transcriptional profile between WT and the c-Flip+/- fetal heads. DEGs in pattern recognition receptor (PRR)-related signaling pathways, such as the RIG-I-like receptor signaling pathway and Toll-like receptor signaling pathway, were enriched. Moreover, the DEGs were also enriched in T cells, indicating that the c-FLIP participates in both innate and adaptive immune responses upon viral infection. Furthermore, our observations indicate that DEGs are associated with sensory organ development and eye development, suggesting a potential role for the c-FLIP in ZIKV-induced organ development defects. Overall, we have provided a comprehensive transcriptional profile for the c-FLIP and its modulation during a ZIKV infection.

Deletion of Interleukin-1β Converting Enzyme Alters Mouse Cardiac Structure and Function.

Interleukin-1β converting enzyme (ICE, caspase-1) is a thiol protease that cleaves the pro-inflammatory cytokine precursors of IL-1β and IL-18 into active forms. Given the association between caspase-1 and cardiovascular pathology, we analyzed the hearts of ICE knockout (ICE KO) mice to test the hypothesis that caspase-1 plays a significant role in cardiac morphology and function. We characterized the histological and functional changes in the hearts of ICE KO mice compared to the Wild type. The cardiomyocytes from the neonatal ICE KO mice showed an impaired response to oxidative stress. Subsequently, the hearts from the ICE KO mice were hypertrophied, with a significant increase in the left ventricular and septal wall thickness and a greater LV mass/body weight ratio. The ICE KO mice hearts exhibited irregular myofibril arrangements and disruption of the cristae in the mitochondrial structure. Proapoptotic proteins that were significantly increased in the hearts of ICE KO versus the Wild type included pErk, pJNK, p53, Fas, Bax, and caspase 3. Further, the antiapoptotic proteins Bag-1 and Bcl-2 are activated in ICE KO hearts. Functionally, there was an increase in the left ventricular epicardial diameter and volume in ICE KO. In conclusion, our findings support the important role of caspase-1 in maintaining cardiac health; specifically, a significant decrease in caspase-1 is detrimental to the cardiovascular system.

Neuroinflammation and status epilepticus: a narrative review unraveling a complex interplay

Status epilepticus (SE) is a medical emergency resulting from the failure of the mechanisms involved in seizure termination or from the initiation of pathways involved in abnormally prolonged seizures, potentially leading to long-term consequences, including neuronal death and impaired neuronal networks. It can eventually evolve to refractory status epilepticus (RSE), in which the administration of a benzodiazepine and another anti-seizure medications (ASMs) had been ineffective, and super-refractory status epilepticus (SRSE), which persists for more than 24 h after the administration of general anesthesia. Objective of the present review is to highlight the link between inflammation and SE. Several preclinical and clinical studies have shown that neuroinflammation can contribute to seizure onset and recurrence by increasing neuronal excitability. Notably, microglia and astrocytes can promote neuroinflammation and seizure susceptibility. In fact, inflammatory mediators released by glial cells might enhance neuronal excitation and cause drug resistance and seizure recurrence. Understanding the molecular mechanisms of neuroinflammation could be crucial for improving SE treatment, wich is currently mainly addressed with benzodiazepines and eventually phenytoin, valproic acid, or levetiracetam. IL-1β signal blockade with Anakinra has shown promising results in avoiding seizure recurrence and generalization in inflammatory refractory epilepsy. Inhibiting the IL-1β converting enzyme (ICE)/caspase-1 is also being investigated as a possible target for managing drug-resistant epilepsies. Targeting the ATP-P2X7R signal, which activates the NLRP3 inflammasome and triggers inflammatory molecule release, is another avenue of research. Interestingly, astaxanthin has shown promise in attenuating neuroinflammation in SE by inhibiting the ATP-P2X7R signal. Furthermore, IL-6 blockade using tocilizumab has been effective in RSE and in reducing seizures in patients with febrile infection-related epilepsy syndrome (FIRES). Other potential approaches include the ketogenic diet, which may modulate pro-inflammatory cytokine production, and the use of cannabidiol (CBD), which has demonstrated antiepileptic, neuroprotective, and anti-inflammatory properties, and targeting HMGB1-TLR4 axis. Clinical experience with anti-cytokine agents such as Anakinra and Tocilizumab in SE is currently limited, although promising. Nonetheless, Etanercept and Rituximab have shown efficacy only in specific etiologies of SE, such as autoimmune encephalitis. Overall, targeting inflammatory pathways and cytokines shows potential as an innovative therapeutic option for drug-resistant epilepsies and SE, providing the chance of directly addressing its underlying mechanisms, rather than solely focusing on symptom control.

An IL-1β homologue induced inflammation and antibacterial immune defense in Siberian sturgeon (Acipenser baeri)

Interleukin-1β is a key pro-inflammatory cytokine functioning in initiation of inflammatory responses against bacterial- and viral-infections. In the present study, a putative IL-1β counterpart was identified from Siberian sturgeon (Acipenser baeri) and designated as AbIL-1β. The Abil-1β cDNA sequence consists of 1130 bp with an open reading frame (ORF) of 585 bp, which encodes a 194 amino acid (aa) protein. Multiple amino acid sequence alignment revealed that a possible mature peptide could start at Leu18, although no cut site for ICE (IL-1β converting enzyme) enzyme was present in Siberian sturgeon IL-1β. Even if AbIL-1β shares a relative low identity (33.6%) with another sturgeon type II IL-1β gene from Acipenser dabryanus, they still clustered together in phylogenetic tree. Endogenous Abil-1β was highly expressed in brain, blood, head kidney and spleen of healthy Siberian sturgeon, and remarkably up regulated in head kidney, spleen, and liver upon Aeromonas hydrophila (A.h) challenge. Consistently, in vitro stimulation test using heat-killed A.h and LPS significantly increased Abil-1β transcripts of primary spleen cells. To investigate the bactericidal capability of AbIL-1β, recombinant AbIL-1β (rAbIL-1β) was generated by prokaryotes. Pre-injection of rAbIL-1β reduced the bacterial load in sturgeon spleen after A.h infection. Further, rAbIL-1β was served as feed additive and demonstrated to enhance hybrid sturgeon's defense against A.h infection by increased expressional levels of immune-related genes (IL-1β, IL-6, IL-8, IgM and MHCIIβ), elevated activities of serum lysosome, ACH50, and MPO, as well as higher percent survival. In summary, the current results suggested that AbIL-1β functions in immune regulation and could improve sturgeon's resistance to bacterial infection.

CTRP3 promotes TNF-α-induced apoptosis and barrier dysfunction in salivary epithelial cells

BackgroundC1q/tumour necrosis factor-related protein 3 (CTRP3) plays important roles in metabolism and inflammatory responses in various cells and tissues. However, the expression and function of CTRP3 in salivary glands have not been explored. MethodsThe expression and distribution of CTRP3 were detected by western blot, polymerase chain reaction, immunohistochemical and immunofluorescence staining. The effects of CTRP3 on tumour necrosis factor (TNF)-α-induced apoptosis and barrier dysfunction were detected by flow cytometry, western blot, co-immunoprecipitation, and measurement of transepithelial resistance and paracellular tracer flux. ResultsCTRP3 was distributed in both acinar and ductal cells of human submandibular gland (SMG) and was primarily located in the ducts of rat and mouse SMGs. TNF-α increased the apoptotic rate, elevated expression of cleaved caspase 3 and cytochrome C, and reduced B cell lymphoma-2 (Bcl-2) levels in cultured human SMG tissue and SMG-C6 cells, and CTRP3 further enhanced TNF-α-induced apoptosis response. Additionally, CTRP3 aggravated TNF-α-increased paracellular permeability. Mechanistically, CTRP3 promoted TNF-α-enhanced TNF type I receptor (TNFR1) expression, inhibited the expression of cellular Fas-associated death domain (FADD)-like interleukin-1β converting enzyme inhibitory protein (c-FLIP), and increased the recruitment of FADD with receptor-interacting protein kinase 1 and caspase 8. Moreover, CTRP3 was significantly increased in the labial gland of Sjögren's syndrome patients and in the serum and SMG of nonobese diabetic mice. ConclusionsThese findings suggest that the salivary glands are a novel source of CTRP3 synthesis and secretion. CTRP3 might promote TNF-α-induced cell apoptosis through the TNFR1-mediated complex II pathway.

Self-Enhanced Carbonized Polymer Dots for Selective Visualization of Lysosomes and Real-Time Apoptosis Monitoring.

SummaryProtons are highly related to cell viability during physiological and pathological processes. Developing new probes to monitor the pH variation could be extremely helpful to understand the viability of cells and the cell death study. Carbonized polymer dots (CPDs) are superior biocompatible and have been widely applied in bioimaging field. Herein, a new type of extreme-pH suitable CPDs was prepared from citric acid and o-phenylenediamine (CA/oPD-CPDs). Due to the co-existence of hydrophilic and hydrophobic groups, CA/oPD-CPDs tend to aggregate in neutral condition with a dramatic decrease of fluorescence, but disperse well in both acidic and alkaline conditions with brighter emission. This specialty enables them to selectively illuminate lysosomes in cells. Moreover, CA/oPD-CPDs in the cytoplasm could serve as a sustained probe to record intracellular pH variation during apoptosis. Furthermore, CA/oPD-CPDs present a continuous fluorescence increase upon 2-h laser irradiation in living cells, underscoring this imaging system for long-term biological recording.

436 Macrophages promote growth of squamous cancer independent of T cells

We assessed the role of macrophages in squamous cell carcinoma (SCC) behavior. We used mouse SCC cells derived from tumors harboring a Kras12D activation mutation and Smad4 deletion in keratin 15 (K15)-positive stem cells, and a human SCC cell line, FaDu. SCC cells were transplanted into immune-compromised or -competent (syngeneic) recipients. After tumors were established, we profiled tumor infiltrating leukocytes using CyTOF. CD45+ leukocytes comprised 10-25% of the total tumor cells, and tumor-associated macrophages (TAMs) were 5-10% of the CD45+ cells. There were typically 2-3 fold more M2 TAMs than M1 TAMs. We used clodronate liposomes to deplete TAMs. We found that the number of TAMs was not affected by the presence of T cells but differed among tumors derived from different SCC lines. Clodronate significantly reduced TAMs and macrophages in the spleen, resulting in reduced SCC volumes. Tumors with clodronate treatment did not show decreased proliferation, but exhibited increased apoptosis and reduced vascular density. FLIP (Fas-associated via death domain-like interleukin-1β converting enzyme inhibitory protein), an apoptosis inhibitor abundantly produced in tumor cells and TAMs, was reduced in tumor cells of clodronate treated mice. Reduced FLIP levels correlated with reductions in phosphorylated nuclear NFkB p65 and NFkB inhibitor attenuated FLIP protein levels in SCC cells. Further, TGFb1 serum levels and pSmad3 were reduced in clodronate-treated mice, but their reductions were insufficient to reverse epithelial-mesenchymal transition (EMT) or TGFb-mediated angiogenesis in endothelial cells. Consequently, metastasis was not significantly reduced by macrophage reduction. However, reduced pSmad3 correlated with reduction of its transcriptional target, vascular endothelial growth factor A (VEGFA), in clodronate-treated tumor cells. Taken together, our study revealed that macrophages contribute to SCC expansion through interactions with tumor cells but are dispensable for SCC metastasis. Our study provides novel insights into understanding the contributions and limitations of TAMs in SCC progression.

Macrophages Promote Growth of Squamous Cancer Independent of T cells

Oral cancers, primarily squamous cell carcinomas (SCCs), progress either slowly or aggressively. Here we assessed the role of macrophages in SCC behavior. We used mouse SCC cells derived from tumors harboring a KrasG12D activation mutation and Smad4 deletion in keratin 15–positive stem cells and a human oral SCC cell line, FaDu, which has NRAS amplification and SMAD4 deletion. SCC cells were transplanted into immune-compromised or immune-competent (syngeneic) recipients. After tumors were established, we used clodronate liposomes to ablate macrophages. We found that the number of tumor-associated macrophages (TAMs) was not affected by the presence of T cells but differed considerably among tumors derived from different SCC lines. Clodronate significantly reduced TAMs and splenic macrophages, resulting in reduced SCC volumes. Tumors with clodronate treatment did not show decreased proliferation but did exhibit increased apoptosis and reduced vascular density. FLIP (Fas-associated via death domain-like interleukin 1β–converting enzyme inhibitory protein), an apoptosis inhibitor abundantly produced in tumor cells and TAMs, was reduced in tumor cells of clodronate-treated mice. Reduced FLIP levels correlated with reductions in phosphorylated nuclear NFκB p65 and NFκB inhibitor attenuated FLIP protein levels in SCC cells. Furthermore, TGFβ1 serum levels and pSmad3 were reduced in clodronate-treated mice, but their reductions were insufficient to reverse epithelial-mesenchymal transition or TGFβ-mediated angiogenesis in endothelial cells. Consequently, metastasis was not significantly reduced by macrophage reduction. However, reduced pSmad3 correlated with reduction of its transcriptional target, vascular endothelial growth factor A, in clodronate-treated tumor cells, which correlated with reduced vascular density in clodronate-treated tumors. Taken together, our study revealed that macrophages contribute to SCC expansion through interactions with tumor cells but are dispensable for SCC metastasis. Our study provides novel insights into understanding the contributions and limitations of TAMs in SCC progression.

Expression and significance of c-FLIP protein in sepsis mice with acute kidney injury

To observe the expression of cellular Fas-associated death domain-like interleukin-1β converting enzyme inhibit protein (c-FLIP) in sepsis mice with acute kidney injury (SAKI) and explore its significance. Thirty male ICR mice were divided into the normal control group (Normal group), sham operation group (Sham group) and SAKI group by random number table method, with 10 mice in each group. The SAKI model of mice was established by cecal ligation and puncture (CLP); the Sham group was not ligated and the cecum was not punctured, and other surgical procedures were the same as the SAKI group; the Normal group did not experience any treatment. The serum and renal tissues of mice in each group were harvested 24 hours after CLP model establishment. The levels of serum creatinine (SCr) and blood urea nitrogen (BUN) were detected by enzyme linked immunosorbent assay (ELISA). The renal tissues were stained with hematoxylin-eosin (HE), and the pathological changes of renal tissues were observed under light microscope and the severity of injury was determined. The expression of c-FLIP in renal tissues was detected by immunohistochemistry. The expression of c-FLIP, Bax and caspase-3 protein in renal tissue was detected by Western Blot. The correlation between c-FLIP expression and Bax, caspase-3 protein expressions in renal tissues were analyzed by Pearson test. In the Normal group and the Sham group, the renal tubular epithelial cells were regular and intact, and no interstitial inflammatory cell infiltration was observed; the renal injury score was both 1.30±0.48; immunohistochemistry showed a large amount of c-FLIP positive expression in renal tubular epithelial cells (IA: 120.20±3.87, 116.70±3.46); Western Blot showed high expression of c-FLIP in renal tissues (c-FLIP/GAPDH: 0.99±0.01, 0.98±0.02), and low expressions of Bax and caspase-3 (Bax/GAPDH: 0.16±0.04, 0.19±0.03, caspase-3/GAPDH: 0.24±0.04, 0.23±0.05). Compared with the Sham group, in the SAKI group, renal tubular epithelial cells were degenerated and necrosis, and a large number of interstitial inflammatory cells infiltrated, the renal injury score was significantly increased (4.60±0.52 vs. 1.30±0.48, P < 0.01); the levels of SCr and BUN were significantly increased [SCr (μmol/L): 193.90±13.54 vs. 24.50±3.78, BUN (mmol/L): 81.60±7.26 vs. 5.20±0.92, both P < 0.01]; the c-FLIP positive cells in renal tissues was significantly reduced (IA: 17.11±0.82 vs. 116.70±3.46, P < 0.01); the expression of c-FLIP protein in renal tissues was significantly decreased (c-FLIP/GAPDH: 0.29±0.03 vs. 0.98±0.02, P < 0.01), while the expressions of Bax and caspase-3 protein were significantly increased (Bax/GAPDH: 0.87±0.06 vs. 0.19±0.03, caspase-3/GAPDH: 0.88±0.07 vs. 0.23±0.05, both P < 0.01]. The correlation analysis showed that the c-FLIP protein was significantly negatively correlated with Bax (r = -0.468, P = 0.029) and caspase-3 protein expressions (r = -0.663, P = 0.004). The expression level of c-FLIP protein was significantly down-regulated in renal tissue of SAKI, and its down-regulation mechanism was associated with increased apoptosis of renal tubular epithelial cells, which could be an effective target for the treatment of SAKI.

Expression and significance of c-FLIP protein in sepsis mice with acute kidney injury

Objective To observe the expression of cellular Fas-associated death domain-like interleukin-1β converting enzyme inhibit protein (c-FLIP) in sepsis mice with acute kidney injury (SAKI) and explore its significance. Methods Thirty male ICR mice were divided into the normal control group (Normal group), sham operation group (Sham group) and SAKI group by random number table method, with 10 mice in each group. The SAKI model of mice was established by cecal ligation and puncture (CLP); the Sham group was not ligated and the cecum was not punctured, and other surgical procedures were the same as the SAKI group; the Normal group did not experience any treatment. The serum and renal tissues of mice in each group were harvested 24 hours after CLP model establishment. The levels of serum creatinine (SCr) and blood urea nitrogen (BUN) were detected by enzyme linked immunosorbent assay (ELISA). The renal tissues were stained with hematoxylin-eosin (HE), and the pathological changes of renal tissues were observed under light microscope and the severity of injury was determined. The expression of c-FLIP in renal tissues was detected by immunohistochemistry. The expression of c-FLIP, Bax and caspase-3 protein in renal tissue was detected by Western Blot. The correlation between c-FLIP expression and Bax, caspase-3 protein expressions in renal tissues were analyzed by Pearson test. Results In the Normal group and the Sham group, the renal tubular epithelial cells were regular and intact, and no interstitial inflammatory cell infiltration was observed; the renal injury score was both 1. 30±0. 48; immunohistochemistry showed a large amount of c-FLIP positive expression in renal tubular epithelial cells (IA: 120. 20±3. 87, 116. 70±3. 46); Western Blot showed high expression of c-FLIP in renal tissues (c-FLIP/GAPDH: 0. 99±0. 01, 0. 98±0. 02), and low expressions of Bax and caspase-3 (Bax/GAPDH: 0. 16±0. 04, 0. 19±0. 03, caspase-3/GAPDH: 0. 24±0. 04, 0. 23±0. 05). Compared with the Sham group, in the SAKI group, renal tubular epithelial cells were degenerated and necrosis, and a large number of interstitial inflammatory cells infiltrated, the renal injury score was significantly increased (4. 60±0. 52 vs. 1. 30±0. 48, P < 0. 01); the levels of SCr and BUN were significantly increased [SCr (μmol/L): 193. 90±13. 54 vs. 24. 50±3. 78, BUN (mmol/L): 81. 60±7. 26 vs. 5. 20±0. 92, both P < 0. 01]; the c-FLIP positive cells in renal tissues was significantly reduced (IA: 17. 11±0. 82 vs. 116. 70±3. 46, P < 0. 01); the expression of c-FLIP protein in renal tissues was significantly decreased (c-FLIP/GAPDH: 0. 29±0. 03 vs. 0. 98±0. 02, P < 0. 01), while the expressions of Bax and caspase-3 protein were significantly increased (Bax/GAPDH: 0. 87±0. 06 vs. 0. 19±0. 03, caspase-3/GAPDH: 0. 88±0. 07 vs. 0. 23±0. 05, both P < 0. 01]. The correlation analysis showed that the c-FLIP protein was significantly negatively correlated with Bax (r = -0. 468, P = 0. 029) and caspase-3 protein expressions (r = -0. 663, P = 0. 004). Conclusions The expression level of c-FLIP protein was significantly down-regulated in renal tissue of SAKI, and its down-regulation mechanism was associated with increased apoptosis of renal tubular epithelial cells, which could be an effective target for the treatment of SAKI. Key words: c-FLIP; Sepsis; Acute kidney injury; Apoptosis

Structure-based design, synthesis and evaluation of 2,4-diaminopyrimidine derivatives as novel caspase-1 inhibitors

Interleukin-1β converting enzyme contributes in various inflammatory and autoimmune diseases by maturing pro-inflammatory cytokines IL-1β, IL-18 and IL-33. Therefore, inhibition caspase-1 may provide a potential therapeutic strategy for the treatment of chronic inflammatory diseases. Here we have reported structure-based design, synthesis and biological evaluation of 2,4-diaminopyrimidine derivatives (6a-6w) as potential caspase-1 inhibitors. Six compounds 6m, 6n, 6o, 6p, 6q and 6r showed significant enzymatic inhibition with IC50 ranging from 0.022 to 0.078 µM. These compounds also displayed excellent cellular potency at sub-micromolar concentration. Moreover, molecular docking studies provided the useful binding insights specific for caspase-1 inhibition. All these results indicated that compounds 6m, 6n and 6o could be potential leads for the development of newer caspase-1 inhibitors as anti-inflammatory agents.

Inflammasome Activation by Methamphetamine Potentiates Lipopolysaccharide Stimulation of IL-1β Production in Microglia

Methamphetamine (Meth) is an addictive psychostimulant abused worldwide. Ample evidence indicate that chronic abuse of Meth induces neurotoxicity via microglia-associated neuroinflammation and the activated microglia present in both Meth-administered animals and human abusers. The development of anti-neuroinflammation as a therapeutic strategy against Meth dependence promotes research to identify inflammatory pathways that are specifically tied to Meth-induced neurotoxicity. Currently, the exact mechanisms for Meth-induced microglia activation are largely unknown. NLRP3 is a well-studied cytosolic pattern recognition receptor (PRR), which promotes the assembly of the inflammasome in response to the danger-associated molecular patterns (DAMPs). It is our hypothesis that Meth activates NLRP3 inflammasome in microglia and promotes the processing and release of interleukin (IL)-1β, resulting in neurotoxic activity. To test this hypothesis, we studied the effects of Meth on IL-1β maturation and release from rat cortical microglial cultures. Incubation of microglia with physiologically relevant concentrations of Meth after lipopolysaccharide (LPS) priming produced an enhancement on IL-1β maturation and release. Meth treatment potentiated aggregation of inflammasome adaptor apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), induced activation of the IL-1β converting enzyme caspase-1 and produced lysosomal and mitochondrial impairment. Blockade of capase-1 activity, lysosomal cathepsin B activity or mitochondrial ROS production by their specific inhibitors reversed the effects of Meth, demonstrating an involvement of inflammasome in Meth-induced microglia activation. Taken together, our results suggest that Meth triggers microglial inflammasome activation in a manner dependent on both mitochondrial and lysosomal danger-signaling pathways.

Involvement of Nucleotide-Binding and Oligomerization Domain-Like Receptors in the Intestinal Injury of Severe Acute Pancreatitis in Rats.

The aim of the study was to observe the role of nucleotide-binding and oligomerization domain (NOD)-like receptors (NLR) in intestinal injury of severe acute pancreatitis (SAP) in rats. Severe acute pancreatitis was induced by retrograde infusion of sodium taurocholate into the biliopancreatic duct. Rats were divided into the following 6 groups: sham operation, SAP treated with saline, and SAP treated with interleukin 1β (IL-1β)-converting enzyme inhibitor, killed at 6 or 12 hours after operation. Serum IL-18 and IL-1β concentrations were measured. mRNA expression and protein levels of NOD1, NOD2, and NLRP3 in the intestine were measured. Severe acute pancreatitis resulted in significantly higher serum IL-18 and IL-1β concentration, higher mRNA expression, and protein levels of NOD1, NOD2, and NLRP3 in intestine in SAP treated with saline groups compared with sham operation groups. This effect was attenuated by administration of IL-1β-converting enzyme inhibitor. The NLRs, including NOD1, NOD2, and NLRP3, were involved in the intestinal injury in SAP through a caspase-1 pathway.

Apoptosis of Acanthamoeba castellanii Trophozoites Induced by Oleic Acid.

Acanthamoeba spp. can be parasitic in certainsituations and are responsible for serious human infections, including Acanthamoeba keratitis, granulomatous amoebic encephalitis, and cutaneous acanthamoebiasis. We analyzed the fatty acid composition of Acanthamoeba castellanii trophozoites and tested the inhibitory activity of the main fatty acids, oleic acid and arachidonic acid, invitro. Oleic acid markedly inhibited the growth of A.castellanii, with trophozoite viability of 57.4% at a concentration of 200μM. Caspase-3 staining and annexin V assays showed that apoptotic death occurred in A.castellanii trophozoites. Quantitative PCR and dot blot analysis showed increased levels of metacaspase and interleukin-1β converting enzyme, which is also an indication of apoptosis. In contrast, arachidonic acid showed negligible inhibition of growth of A.castellanii trophozoites. Stimulated expression of Atg3, Atg8 and LC3A/B genes and monodansylcadaverine labeling suggested that oleic acid induces apoptosis by triggering autophagy of trophozoites.

MOLECULAR DOCKING, PHARMACOPHORE MODELLING, AND ADME-TOXICITY PREDICTION OF CURCUMIN ANALOG COMPOUNDS AS INFLAMMATORY INHIBITOR ON RHEUMATOID ARTHRITIS

Objective: The objective of this research was to examine the activity and cytokine inhibitory mechanism of curcumin analog compound against multiple protein targets in a patient with rheumatoid arthritis (RA) and identify the absorption, distribution, metabolism, excretion and toxicity (ADME-toxicity).Methods: Identification was carried out by in silico through pharmacophore modelling using Ligand Scout, molecular docking using iGemDock in various protein (tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), transcription factors, signalling kinase, and cyclooxygenase enzyme) and identification of ADME-toxicity based on the physicochemical properties of the compound to simulate, predict and analyze interaction between protein and compound.Results: The obtained results indicated that gamavuton (GVT-0) and penta-gamavuton (PGV) possessed high bioavailability with lower toxicity than curcumin. However, GVT-0, a curcumin analog, possessed high and specific inhibitory activity on tumor necrosis factor-α converting enzyme (TACE) and interleukin converting enzyme (ICE)/Caspase-1.Conclusion: GVT-0 as a curcumin derivate possessed the best inhibitory activity against TNF-α converting enzyme and IL-1β converting enzyme which are the main route of inflammatory mediators in rheumatoid arthritis. In addition, GVT-0 influences less in metabolism of CYP450 enzymes, and has low toxicity.

Differential roles of caspase-1 and caspase-11 in infection and inflammation

Caspase-1, also known as interleukin-1β (IL-1β)-converting enzyme (ICE), regulates antimicrobial host defense, tissue repair, tumorigenesis, metabolism and membrane biogenesis. On activation within an inflammasome complex, caspase-1 induces pyroptosis and converts pro-IL-1β and pro-IL-18 into their biologically active forms. “ICE−/−” or “Casp1−/−” mice generated using 129 embryonic stem cells carry a 129-associated inactivating passenger mutation on the caspase-11 locus, essentially making them deficient in both caspase-1 and caspase-11. The overlapping and unique functions of caspase-1 and caspase-11 are difficult to unravel without additional genetic tools. Here, we generated caspase-1–deficient mouse (Casp1Null) on the C57BL/6 J background that expressed caspase-11. Casp1Null cells did not release IL-1β and IL-18 in response to NLRC4 activators Salmonella Typhimurium and flagellin, canonical or non-canonical NLRP3 activators LPS and ATP, Escherichia coli, Citrobacter rodentium and transfection of LPS, AIM2 activators Francisella novicida, mouse cytomegalovirus and DNA, and the infectious agents Listeria monocytogenes and Aspergillus fumigatus. We further demonstrated that caspase-1 and caspase-11 differentially contributed to the host defense against A. fumigatus infection and to endotoxemia.

Roxatidine attenuates mast cell-mediated allergic inflammation via inhibition of NF-\u03baB and p38 MAPK activation

Roxatidine is an active metabolite of roxatidine acetate hydrochloride which is a histamine H2-receptor antagonist that is used to treat gastric and duodenal ulcers. In this study, we investigated the anti-allergic inflammatory effects and the underlying molecular mechanism of roxatidine in phorbol 12-myristate 13-acetate and calcium ionophore (PMACI)-stimulated human mast cells-1 (HMC-1), compound 48/80-induced anaphylactic animal model and chemical allergen-induced contact hypersensitivity (CHS) models. Roxatidine suppressed the mRNA and protein expression of inflammatory cytokines such as TNF-α, IL-6, and IL-1β in PMACI-stimulated HMC-1 and compound 48/80-induced anaphylactic mice. In addition, roxatidine attenuated PMACI-induced nuclear translocation of NF-κB and the phosphorylation of MKK3/6 and MK2, which are both involved in the p38 MAPK pathway. Furthermore, we observed that roxatidine suppressed the activation of caspase-1, an IL-1β converting enzyme, in PMACI-stimulated HMC-1 and compound 48/80-induced anaphylactic mice. In CHS model, roxatidine significantly reduced ear swelling, increased number of mast cells, production levels of cytokines and migration of dendritic cells. Our findings provide evidence that the anti-allergic inflammatory properties of roxatidine are mediated by the inhibition of NF-κB and caspase-1 activation, p38 MAPK pathway and mast cell-derived cytokine production. Taken together, the in vitro and in vivo anti-allergic inflammatory effects suggest a possible therapeutic application of roxatidine in allergic inflammatory diseases.

Interferon regulatory factor 1 attenuates vascular remodeling; roles of angiotensin II type 2 receptor

We previously reported interferon regulatory factor (IRF) 1 plays physiological roles in “growth”-regulated angiotensin II type 2 (AT2) receptor expression in fibroblasts. Here, we investigated whether IRF-1 is involved in attenuation of vascular remodeling in association with AT2 receptor upregulation. Neointimal area in injured artery after 14 days of cuff placement was significantly increased in IRF-1 knockout mice (IRF-1KO) and AT2 receptor knockout mice (AT2KO) compared with wild-type mice (WT: C57BL/6J). Treatment with compound 21 attenuated neointima formation in both WT and IRF-1KO. AT2 receptor mRNA expression after 7 days of cuff placement was significantly decreased in IRF-1KO compared with WT; however, IRF-1 expression did not differ between AT2KO and WT. Apoptotic changes in injured artery after 14 days of cuff placement were significantly attenuated in IRF-1KO, with a decrease in interleukin-1β–converting enzyme and inducible nitric oxide synthase mRNA levels. These results indicate IRF-1 is one of the key transcriptional factors for the prevention of neointimal formation involving AT2 receptors.

Dibutyltin-induced alterations of interleukin 1beta secretion from human immune cells.

Dibutyltin (DBT) is used to stabilize polyvinyl chloride plastics (including pipes that distribute drinking water) and as a de-worming agent in poultry. DBT is found in human blood, and DBT exposures alter the secretion of tumor necrosis factor alpha and interferon gamma from lymphocytes. Interleukin (IL)-1β is a proinflammatory cytokine that regulates cellular growth, tissue restoration and immune response regulation. IL-1β plays a role in increasing invasiveness of certain tumors. This study reveals that exposures to DBT (24 h, 48 h and 6 days) modify the secretion of IL-1β from increasingly reconstituted preparations of human immune cells (highly enriched human natural killer cells, monocyte-depleted [MD] peripheral blood mononuclear cells [PBMCs], PBMCs, granulocytes and a preparation combining both PBMCs and granulocytes). DBT altered IL-1β secretion from all cell preparations. Higher concentrations of DBT (5 and 2.5 μm) decreased the secretion of IL-1β, while lower concentrations of DBT (0.1 and 0.05 μm) increased the secretion of IL-1β. Selected signaling pathways were examined in MD-PBMCs to determine if they play a role in DBT-induced elevations of IL-1β secretion. Pathways examined were IL-1β converting enzyme (caspase 1), mitogen-activated protein kinases and nuclear factor kappa B. Caspase 1 and mitogen-activated protein kinase pathways appear to be utilized by DBT in increasing IL-1β secretion. These results indicate that DBT alters IL-1β secretion from human immune cells in an ex. vivo system utilizing several IL-1β regulating signaling pathways. Thus, DBT may have the potential to alter IL-1β secretion in an in vivo system. Copyright © 2016 John Wiley & Sons, Ltd.

Identification and Functional Analysis of Interleukin-1β in the Chinese Soft-Shelled Turtle Pelodiscus sinensis.

Chinese soft-shelled turtle (Pelodiscus sinensis) is commercially cultured in East and Southeast Asia for its nutritional and medicinal values. In this study, we identified interleukin-1β (IL-1β) from Chinese soft-shelled turtle. The full-length cDNA of Pelodiscus sinensis IL-1β (tIL-1β) consists of 1529 base pairs with an 831-base-pair open reading frame, encoding 277 amino acids. The guanine-cytosine (GC) content in the coding sequence and 3’ untranslated region of tIL-1β is considerably higher than that of other vertebrates. Its mRNA expression level increased significantly during Aeromonas hydrophila infection. The tIL-1β lacks the typical IL-1β-converting enzyme (ICE) cut site found in mammalian IL-1β, but still could be cleaved by turtle caspase-1. By mutating the potential cleavage sites, we identified aspartic acid (Asp/D) 130 as the ICE cut site in tIL-1β. The peptide truncated at D130 was expressed using the baculovirus expression system; its bioactivity is confirmed by the ability to induce cyclooxygenase-2 (COX-2) and tIL-1β itself in peripheral blood monocytes. In conclusion, we characterized IL-1β from Chinese soft-shelled turtle and identified its D130 as a non-typical ICE cut size.