Preclinical evidence of sphingosine kinase 1 inhibition in alleviation of intestinal epithelial injury in polymicrobial sepsis Abstract Background Intestinal epithelial injury in septic patients predicts subsequent development of multiple organ failure, but its regulation by host factors remains unclear. Sphingosine kinase 1 is an enzyme-regulating inflammatory response. Methods Cecal ligation and puncture was used to induce sepsis in C57BL/6 mice with and without N,N-dimethylsphingosine, a SphK1 inhibitor. Symptom severity was monitored by murine sepsis severity score. The intestinal barrier function was determined using 4KDa fluorescein-dextran. Bacterial load in the bloodstream was determined by 16S rRNA gene amplification. Results and conclusions Our preliminary experimental data showed that expression of sphingosine kinase 1 in ileum was increased by sixfold in septic mice. Pharmacological blockade of sphingosine kinase 1 alleviated septic symptoms. The intestinal permeability and bacterial load in the bloodstream were also reduced in these animals. We hypothesized that inhibition of sphingosine kinase 1 may reduce pro-inflammatory cytokine production, and alleviate intestinal epithelial injury during sepsis. Further mechanistic studies and clinical specimen analyses are warranted.

Macrophage lipid accumulation in the presence of immunosuppressive drugs mycophenolate mofetil and cyclosporin A Abstract Objective Mycophenolate (MPA) and cyclosporin A (CsA) are two immunosuppressive agents currently used for the treatment of autoimmune diseases. However, reports regarding their effects on inflammation and lipid handling are controversial. Here, we compare the effect of these two drugs on the expression of proteins involved in cholesterol handling and lipid accumulation in a macrophage cell system utilizing M0, M1 and M2 human macrophages and in murine bone marrow-derived macrophages (BMDM). Methods Differentiated M0, M1 and M2 subsets of THP-1 human macrophages were subjected to various concentrations of either MPA or CsA. Expression of proteins involved in reverse cholesterol transport (ABCA1 and 27-hydroxylase) and scavenger receptors, responsible for uptake of modified lipids (CD36, ScR-A1, CXCL16 and LOX-1), were evaluated by real-time PCR and confirmed with Western blot. DiI-oxidized LDL internalization assay was used to assess foam cell formation. The influence of MPA was also evaluated in BMDM obtained from atherosclerosis-prone transgenic mice, ApoE−/− and ApoE−/−Fas−/−. Results In M0 macrophages, MPA increased expression of ABCA1 and CXCL16 in a concentration-dependent manner. In M1 THP-1 macrophages, MPA caused a significant increase of 27-hydroxylase mRNA and CD36 and SR-A1 receptor mRNAs. Exposure of M2 macrophages to MPA also stimulated expression of 27-hydroxylase, while downregulating all evaluated scavenger receptors. In contrast, CsA had no impact on cholesterol efflux in M0 and M1 macrophages, but significantly augmented expression of ABCA1 and 27-hydroxylase in M2 macrophages. CsA significantly increased expression of the LOX1 receptor in naïve macrophages, downregulated expression of CD36 and SR-A1 in the M1 subpopulation and upregulated expression of all evaluated scavenger receptors. However, CsA enhanced foam cell transformation in M0 and M2 macrophages, while MPA had no effect on foam cell formation unless used at a high concentration in the M2 subtype. Conclusions Our results clearly underline the importance of further evaluation of the effects of these drugs when used in atherosclerosis-prone patients with autoimmune or renal disease.

Inhibition of JAK2/STAT3 signaling pathway protects mice from the DDP-induced acute kidney injury in lung cancer Abstract Objective To explore AG490 (the inhibitor of Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 pathway) in cisplatin (DDP)-induced acute kidney injury (AKI) in mice with lung cancer. Methods Mice were randomly divided into normal, model, AG490, DDP and DDP + AG490 groups. The lung cancer models were established except for Normal group. The levels of blood urea nitrogen (BUN) and creatinine and the status of oxidative stress were detected. Then, histological changes were assessed by HE and PAS staining and apoptosis by TUNEL experiment. The molecule expressions were detected by qRT-PCR and western blot, and immunohistochemistry, respectively. Results DDP inhibited the tumor growth in mice with lung cancer, which was further promoted by the combination with AG490. Mice in the DDP group had elevated levels of BUN and creatinine than those in the Normal group with the increased inflammatory cytokines (TNF-α, IL-6, MCP-1 and CXCL-1) and malondialdehyde (MDA) level and the decreased glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). In addition, DDP could activate the JAK2/STAT3 pathway to promote the apoptosis by upregulating Bax, cleaved caspase-9 and cleaved caspase-3 while downregulating the Bcl-2 in the kidney tissues. DDP + AG490 group showed the alleviated AKI and the improvements in oxidative stress, inflammatory responses and apoptosis in the kidney tissues, as compared to DDP group. Conclusion AG490 alleviated DDP-induced AKI in lung cancer mice with improved oxidative stress and inflammation, and the suppression of JAK2/STAT3 pathway.

Activation of the Notch signaling pathway disturbs the CD4 + /CD8 + , Th17/Treg balance in rats with experimental autoimmune uveitis Abstract Objective and design The present study aimed to investigate the relationship between the disturbed balance of CD4+/CD8+, Th17/Treg and the activation of the Notch signaling pathway in experimental autoimmune uveitis (EAU). Methods An EAU rat model was induced in Lewis rats, and pathology analysis was performed by hematoxylin and eosin (H&E) staining. CD4+, CD8+, Th17, and Treg levels in spleen, lymph nodes and eye tissues were determined by flow cytometry. Meanwhile, the expression of Notch1, DLL4, IL-10, and IL-17 was determined by quantitative polymerase chain reaction (Q-PCR) and enzyme-linked immunosorbent assay (ELISA). In addition, the inhibitory effect of N-(N-(3,5-difluorophenacetyl-l-alanyl))-S-phenylglycine t-butyl ester (DAPT) on Th17 differentiation by Notch signaling in vitro was further investigated using T lymphocytes from EAU rats on day 12 post-immunization by flow cytometry. Results The pathological results showed that inflammatory cell infiltration occurred in ocular tissues in EAU rats. The CD4+/CD8+ and Th17/Treg ratios in EAU rats were apparently higher than those in normal control individuals. Q-PCR and ELISA analyses indicated the expression of Notch1, DLL4, IL-10, and IL-17 in EAU rats gradually increased on day 6 after immunization, peaked on day 12, and then gradually decreased. The dynamic trends in Notch1 and DLL4 expression in EAU rats were identical to those of CD4+/CD8+and Th17/Treg levels. DAPT can significantly inhibit the activation of Notch signaling, decrease Th17 cell differentiation, and attenuate the level of the Th17 cell lineage, contributing to the balance of the Th17/Treg ratio. Conclusion The activation of the Notch signaling pathway can regulate Th17 and Treg cell differentiation, disrupt the CD4+/CD8+ and Th17/Treg balance, and aggravate the severity of EAU; inactivation of the Notch signaling pathway contributes to the CD4+/CD8+ and Th17/Treg balance in EAU rats. Our findings highlighted that the dynamic change in the CD4+/CD8+ and Th17/Treg ratio was consistent with the expression trend of Notch signaling in EAU rats, suggesting that Notch signaling may be a potentially important therapeutic target in clinical practice.

Neferine inhibits LPS-ATP-induced endothelial cell pyroptosis via regulation of ROS/NLRP3/Caspase-1 signaling pathway Abstract Background Oxidative stress-induced endothelial dysfunction and pyroptosis play an important role during chronic kidney disease (CKD) progression. Neferine, which is an alkaloid ingredient from the lotus seed embryo, has many biological actions such as anti-inflammatory, anticancer and antioxidant. However, the role of neferine in endothelial cell pyroptosis and the involved mechanism remain obscure. The aim is to probe the protective effects of neferine on cell pyroptosis and the involved underlying mechanism. Methods After the HUVECs were primed with neferine treatment for 2 h prior to LPS and ATP exposure for 24 h, the cell proliferation was determined by BrdU; the cell LDH release was detected by LDH kits; the levels of intracellular ROS, MDA and SOD were tested by detection kits; Caspase-1 activity kit was used to determine caspase-1 activity; the contents of NLRP3, ASC, caspase-1, IL-1β, IL-18 and GSDMD were tested by RT-PCR and western blot. Results We found that neferine could inhibit LPS-ATP-induced oxidative stress and the activation of NLRP3 inflammasome signaling, and increased the endothelial cell viability and SOD production. siRNA which mediated the knockdown of NLRP3 promoted the neferine-induced inhibition effects of cell pyroptosis. Furthermore, these neferine-induced effects were reversed by the over-expression of NLRP3. Conclusions Our findings indicated neferine may reduce ROS by anti-oxidation and inhibit LPS-ATP-induced endothelial cell pyroptosis via blocking ROS/NLRP3/Caspase-1 signaling pathway, which provides the evidence for therapeutic effect in CKD.

Common variants of genes encoding TLR4 and TLR4 pathway members TIRAP and IRAK1 are effective on MCP1, IL6, IL1β, and TNFα levels in type 2 diabetes and insulin resistance Abstract Objective and design Type 2 diabetes is a pandemic disease characterized by hyperglycemia, ineffective insulin use, and insulin resistance and affecting 1 in 11 people worldwide. Inflammation-related insulin resistance is thought to play an important role in the etiology of the disease. TLR4 is the central receptor of the natural immune system and has an important role as a trigger of the inflammatory response. The IRAK1 and TIRAP are members of the TLR4 pathway and involved in the TLR4-mediated inflammatory response. Genetic variants in the TLR4 gene or in the IRAK1 and TIRAP genes may have an important role in the development of insulin resistance and type 2 diabetes by disrupting the inflammatory response. In this direction, we aimed to investigate the relationship among TLR4 and IRAK1, TIRAP gene variants, and type 2 diabetes and insulin resistance, and investigate how these variants affect inflammatory factors (TNF-α, IL-6, MCP-1, and IL-1β). Subjects and methods In our study, a total of seven variations on the genes of TLR4 (rs4986790, rs4986791), IRAK1 (rs1059703, rs3027898, rs7061789), and TIRAP (rs8177374, rs8177400) were genotyped by the MassARRAY® Iplex GOLD SNP genotyping in 100 type 2 diabetic patients and 100 non-diabetic individual. The TLR4 rs4986790 and rs4986791 variation was confirmed by PCR–RFLP method also. The serum IL1-β, IL6, MCP-1, and TNF-α levels were measured using enzyme-linked immunosorbent assay kits. Results and conclusion As a result of our study, no correlation was found among TLR4, IRAK1, and TIRAP gene variants and the risk of type 2 diabetes and insulin resistance. However, TNF-α, IL-6, MCP-1, and IL-1β levels were also associated with diabetes and insulin resistance (p > 0.05). Although the gene variants were not significant in type 2 diabetes and insulin resistance groups, IRAK1, TLR4, and TIRAP gene variants were found to be associated with TNF-α, IL-6, MCP-1, and IL-1β levels.

ER stress abrogates the immunosuppressive effect of IL-10 on human macrophages through inhibition of STAT3 activation Abstract Objective and design To determine whether ER stress affects the inhibitory pathways of the human immune system, particularly the immunosuppressive effect of IL-10 on macrophages. Material or subjects In vitro stimulation of human monocyte-derived macrophages. Treatment Cells were stimulated with TLR ligands and IL-10, while ER stress was induced using thapsigargin or tunicamycin. Methods mRNA expression was determined using qPCR, while cytokine protein production was measured using ELISA. Protein expression of receptors and transcription factors was determined using flow cytometry. Student’s t test was used for statistics. Results While under normal conditions IL-10 potently suppresses pro-inflammatory cytokine production by LPS-stimulated macrophages, we demonstrate that ER stress counteracts the immunosuppressive effects of IL-10, leading to increased pro-inflammatory cytokine production. We identified that ER stress directly interferes with IL-10R signaling by reducing STAT3 phosphorylation on Tyr705, which thereby inhibits the expression of SOCS3. Moreover, we show that ER stress also inhibits STAT3 activation induced by other receptors such as IL-6R. Conclusions Combined, these data uncover a new general mechanism by which ER stress promotes inflammation. Considering its potential involvement in the pathogenesis of diseases such as Crohn’s disease and spondyloarthritis, targeting of this mechanism may provide new opportunities to counteract inflammation.

STAT3-induced SMYD3 transcription enhances chronic lymphocytic leukemia cell growth in vitro and in vivo Abstract Objective and design The purpose of this study was to investigate the roles of SMYD3 and STAT3 in chronic lymphocytic leukemia (CLL) and the possible underlying mechanisms. Materials Blood samples were collected from 20 patients with CLL and 20 hematologically normal donors. Human cell lines K562, HL-60, MEG-1, and BALL-1 were performed in vitro and BALB/c nude mouse was used in subcutaneous tumor experiments. Treatment WP1066 (30 mg/kg) was also injected intratumorally two days after the first lentivirus treatment and then every four days for a total of four injections and 3 µM WP1066 was carried out for 48 h to downregulate STAT3 phosphorylation. Methods We performed studies using the human CLL cell line MEG-1 in vitro and nude mouse subcutaneous tumor experiments in vivo. Differential expression of RNAs was determined using qRT-PCR. The CCK-8 assay and colony formation assay were conducted to evaluate cell proliferation. Flow cytometry was performed to assess cell apoptosis. The relative protein levels were detected using western blotting. Chromatin immunoprecipitation (ChIP) assays, luciferase reporter assays and WP1066, a STAT3 inhibitor, were used to explore the regulatory mechanisms of proteases and transcription factors. A subcutaneous tumor model was constructed to verify the results in vivo. Results SMYD3 and STAT3 expressions positively correlated with the progression of CLL. Upregulation of SMYD3 significantly promoted the proliferation and inhibited the expression of apoptosis-related genes. The results of the ChIP assays and luciferase reporter assays suggested that STAT3 targeted the promoter region of SMYD3 and, thus, promoted SMYD3 transcription. Downregulation of the phosphorylation of STAT3 by WP1066 notably inhibited the binding of STAT3 to the SMYD3 promoter, and subsequently downregulated SMYD3 transcription. The STAT3 inhibitor inhibited CLL cell growth in vivo, and overexpression of SMYD3 promoted CLL cell growth. Furthermore, overexpression of SMYD3 reversed the inhibitory effects of the STAT3 inhibitor on CLL cell growth. Conclusions The STAT3-mediated transcription of SMYD3 plays a role in promoting the progression of chronic lymphocytic leukemia.

HMGB1 decreases CCR-2 expression and migration of M2 macrophages under hypoxia Abstract Objective The hypoxic milieu at tumor microenvironment is able to drive the behavior of infiltrating tumor cells. Considering that hypoxia-mediated HMGB1 release is known to promote tumor growth, as well to enhance the pro-tumoral profile of M2 macrophages by a RAGE-dependent mechanism, it is tempting to evaluate the potential contribution of HMGB1 under hypoxia to restrain M2 macrophages mobility. Methods CCR-2 expression was evaluated in M2 polarized macrophages by western blotting and immunocytochemistry. The secreted levels of CCL-2 and the migration capability were evaluated using an ELISA and a chemotaxis assay, respectively. Results HMGB1, under hypoxic conditions, markedly reduce both the production of CCL-2 and the expression of its receptor CCR-2; and reduced the migration capacity of M2 macrophages. Conclusions These results provided new insights into the mechanisms that regulate M2 macrophages mobility at the tumor microenvironment.

Salsalate ameliorates the atherosclerotic response through HO-1- and SIRT1-mediated suppression of ER stress and inflammation Abstract Objective and design Inflammation plays a causative role in atherosclerosis development. Salsalate is an anti-inflammatory drug used to treat atherosclerosis, but the mechanisms by which it affects atherosclerotic progression remain unclear. Methods Human umbilical vascular endothelial cells (HUVECs) and THP-1 human monocytes were treated with salsalate. Heme oxygenase 1 (HO-1) and sirtuin 1 (SIRT1) small interfering RNAs (siRNAs) were used to suppress each gene expression. Protein analyses were performed for measuring the expression of HO-1, SIRT1, nuclear factor kappa B (NFκB), cell adhesion molecules, and endoplasmic reticulum (ER) stress markers. Furthermore, cell adhesion assay, caspase 3 activity assay, and ELISA were also performed. Results In this study, we show that salsalate increases the expression of HO-1 and SIRT1 in HUVEC and suppresses lipopolysaccharide (LPS)-induced atherosclerotic responses via HO-1- and SIRT1-mediated pathways. Salsalate treatment of HUVEC and THP-1 cells reduced LPS-induced phosphorylation of NFκB and secretion of the proinflammatory cytokines TNFα and MCP-1. Salsalate treatment of HUVEC reduced the expression of the adhesion molecules ICAM, VCAM, and E-selectin and the LPS-induced adhesion of THP-1 cells to HUVEC. Salsalate treatment also attenuated LPS-induced ER stress and cell apoptosis. These anti-atherosclerotic effects were reversed by treating cells with siRNA for HO-1 and SIRT1. Conclusions Salsalate ameliorates LPS-induced atherosclerotic reactions via HO-1 and SIRT1-dependent reduction of inflammation and ER stress. Activation of these pathways by salsalate may provide therapeutic strategies for treating atherosclerosis.