Glucosylation endows nanoparticles with TLR4 agonist capability to trigger macrophage polarization and augment antitumor immunity

Carbohydrates have emerged as promising candidates for immunomodulation, however, how to present them to immune cells and achieve potent immunostimulatory efficacy remains challenging. Here, we proposed and established an effective way of designing unique glyconanoparticles that can amplify macrophage-mediated immune responses through structural mimicry and multiple stimulation. We demonstrate that surface modification with glucose can greatly augment the immunostimulatory efficacy of nanoparticles, comparing to mannose and galactose. In vitro studies show that glucosylation improved the pro-inflammatory efficacy of iron oxide nanoparticles (IONPs) by up to 300-fold, with the immunostimulatory activity of glucosylated IONPs even surpassing that of LPS under certain conditions. In vivo investigation show that glucosylated IONPs elicited increased antitumor immunity and achieved favorable therapeutic outcomes in multiple murine tumor models. Mechanistically, we proposed that glucosylation potentiated the immunostimulatory effect of IONPs by amplifying toll-like receptors 4 (TLR4) activation. Specifically, glucosylated IONPs directly interacted with the TLR4-MD2 complex, resulting in M1 macrophage polarization and enhanced antitumor immunity via activation of NF-κB, MAPK, and STAT1 signaling pathways. Our work provides a simple modification strategy to endow nanoparticles with potent TLR4 agonist effects, which may shed new light on the development of artificial immune modulators for cancer immunotherapy.

Regulation of Nur77-TLR4/MyD88 signaling pathway is required for Ginsenoside Rc ameliorates hepatic fibrosis regression by deactivating hepatic stellate cells

HSCs (hepatic stellate cells) contribute to the excessive extracellular matrix (ECM) deposition plays a key role in the progression of hepatic fibrosis. The present study focused on the hepatoprotective effect of Ginsenoside Rc (Rc), one of the protopanaxadiol type ginsenoside, which has contributed to reverse activated HSCs to improve hepatic fibrosis via regulating Nur77-TLR4/MyD88 signaling pathway. We established the hepatic fibrosis model by intraperitoneal injection of carbon tetrachloride (CCl4). And HSCs were stimulated with TGF-β, followed by silencing of Nur77, and then incubated in Rc. Rc significantly alleviated histopathological changes, reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Rc could upregulate the Nur77 and downregulate fibrosis markers in the liver of mice, including decreasing the expressions of α-SMA, Collagen-I, the ratio of TIMP-1/MMP-13. Rc significantly increased the expression of Nur77 and suppressed the production of ECM in HSCs. Rc inhibited TLR4 signaling pathway, consequently reversing the inflammatory response, including the production of MyD88, IRAK1, IRAK4 and IL-23. When Nur77 was knocked in TGF-β-stimulated HSCs, TLR4 and α-SMA production were increased. Rc suppressed these activatory effects in Nur77 knockdown HSCs. Rc reduced inflammatory reaction by regulating the Nur77-TLR4 signaling pathway while suppressing the fibrogenesis suggesting, underscoring a promising approach of Rc for the treatment in hepatic fibrosis. Targeting Nur77-TLR4 signaling in HSCs would be the potential strategy for Rc against hepatic fibrosis.

[Mechanism of electroacupuncture penetration needling for relieving synovial inflammation of knee osteoarthritis through TLR4/MyD88/NF-κB signal pathway]

OBJECTIVE

To observe the effects of electroacupuncture (EA) penetration needling on Toll-like receptors 4/myeloid differentiation factor 88/nuclear factor-kappa B (TLR4/MyD88/NF-κB) signaling pathway in rat synovium and the serum-related inflammatory factors, so as to explore the mechanism of EA penetration needling on synovial inflammation in rats with knee osteoarthritis (KOA).

METHODS

SD male rats were randomly divided into sham-operation group, model group, EA+penetration needling group, and conventional EA group, with 16 rats in each group. The rats model was prepared by anterior cruciate ligment transection and these rats were forced to exercise for 8 weeks after operation. After successful modeling, in the EA+penetration needling group, the needles were inserted at "Dubi" (ST35) "Neixiyan" (EX-LE4), and at "Xuehai"(SP10) "Liangqiu"(ST34) on the right hind limb, towards each other, 5-8 mm in depth, respectively. In the conventional EA group, the needles were inserted at ST35 and EX-LE4 on the right hind limb, obliquely, at 30° angle to the skin, 3-5 mm in depth; and were inserted at SP10 and ST34 on the right hind limb perpendicularly, 3-5 mm in depth. In these two groups, electric stimulation was operated with dense-disperse wave, 2 Hz/10 Hz in frequency and 0.5-1.5 mA in intensity, retained for 20 min in each treatment. The treatment was given once daily, 10 days as 1 course of treatment, and 2 courses were required at the interval of 2 days. After the intervention, the knee joint effusion was observed by musculoskeletal ultrasound; the contents of IL-1β, IL-6 and TNF-α in serum were determined by ELISA; the morphological changes in the synovium were observed after H.E. staining; the positive expression of NF-κB p65 in the synovial membrane was detected by immunohistochemical method; the expression levels of TLR4, MyD88, TRAF-6 and NF-κB p65 proteins in the synovial membrane were determined by Western blot.

RESULTS

Compared with the sham-operation group, in the model group, the knee joint effusion was obviously increased, the synovial lining cells were distributed irregularly, the cells were disarranged, the pannus was formed largely, and a great number of the inflammatory cells were infiltrated; the contents of serum IL-1β, IL-6 and TNF-α, the positive expression of NF-κB p65, the protein expression levels of TLR4, MyD88, TRAF-6 and NF-κB p65 in the synovial tissue were increased (P<0.05). Compared with the model group, the knee joint effusion was reduced, the synovial lining cells were proliferated, a small number of the inflammatory cells were infiltrated, and the pannus was formed lightly; the contents of serum IL-1β, IL-6 and TNF-α, the positive expression of NF-κB p65, the protein expression levels of TLR4, MyD88, TRAF-6 and NF-κB p65 in the synovial tissue were lower (P<0.05) in the EA+penetration needling group and the conventional EA group. In the conventional EA group, the knee joint effusion was increased, the synovial lining cells were proliferated, the inflammatory cells were infiltrated largely, and the pannus was formed increasingly; the contents of serum IL-1β, IL-6 and TNF-α, and the protein expression levels of TLR4, MyD88 and NF-κB p65 in the synovial tissue were increased when compared with the EA+penetration needling group (P<0.05).

CONCLUSION

The EA+penetration needling can significantly relieve the synovial inflammatory reaction and the knee joint effusion in KOA rats. The mechanism is probably related to down-regulating the downstream inflammatory cascade through inhibiting the transduction of TLR4/MyD88/NF-κB signaling pathway.

Assessing cell chimerism in an acute graft-versus-host disease model established in TLR4 knockout mice

BACKGROUND

Graft-versus-host disease (GVHD) is a major complication after allogeneic hematopoietic stem cell transplantation.

OBJECTIVE

To elucidate the role of Toll-like receptor 4 (TLR4), the major receptor for bacterial lipopolysaccharide, in the development of GVHD, we constructed a GVHD model in TLR4 knockout (TLR4-/-) mice and monitored the cell chimerism.

METHODS

In this study, we used polymerase chain reaction to identify whether TLR4 knockout (TLR4-/-) mice were established. Before transplantation, we pretreated mice with irradiation so as to obtain an appropriate irradiation dose. Flow cytometry was applied to measure the chimerism status, the distributions of antigen-presenting cells (APCs), and T-cells in TLR4+/+ and TLR4-/- recipient mice.

RESULTS

The general condition of TLR4-/- recipients was better than that of TLR4+/+ recipients, and the TLR4-/- recipient mice showed less severe GVHD manifestations than the TLR4+/+ recipient mice. Most of the APCs and T-cells in the host mouse spleen were derived from donor cells, and CD4+ T-cells, including memory T-cells, were in the majority in host mice.

CONCLUSION

In general, our data show that TLR4 deletion attenuated GVHD development, which suggests that TLR4 could be used as a novel target and therapeutic paradigm in GVHD therapies.

Regulation of SIRT1-TLR2/TLR4 pathway in cell communication from macrophages to hepatic stellate cells contribute to alleviates hepatic fibrosis by Luteoloside

Regulating macrophage-hepatic stellate cells (HSCs) crosstalk through SIRT1-TLR2/TLR4 has contributed to the essence of new pharmacologic strategies to improve hepatic fibrosis. We investigated how Luteoloside (LUT), one of the flavonoid monomers isolated from Eclipta prostrata (L.) L., modulates macrophage-HSCs crosstalk during hepatic fibrosis. HSC-T6 or rat peritoneal macrophages were activated by TGF-β or LPS/ATP, and then treated with LUT or Sirtinol (SIRT1 inhibitor) for 6 h. Further, HSCs were cultured with the conditioned medium from the LPS/ATP activated peritoneal macrophages. In HSC-T6 or peritoneal macrophages, LUT could decrease the expressions of α-SMA, Collagen-I, the ratio of TIMP-1/MMP-13. LUT also significantly increased the expressions of SIRT1 and ERRα. And LUT significantly suppressed the releases of pro-inflammatory cytokines, including NLRP3, ASC, caspase-1, IL-1β, and regulated signaling TLR2/TLR4-MyD88 activation. The expressions of TLR2, TLR4, NLRP3, caspase-1, IL-1β, α-SMA were increased and the expression of ERRα was decreased by Sirtinol, indicated that LUT might mediate SIRT1 to regulate TLR4 expression and further alleviate inflammation and fibrosis. LUT could regulate SIRT1-mediated TLR4 and ECM in HSCs was reduced, when HSCs were cultured with conditioned medium. Hence, LUT could decrease the expressions of fibrosis markers, reduce the releases of inflammatory cytokines in activated HSCs or macrophages. In conclusion, LUT might be a promising candidate that regulating SIRT1-TLR2/TLR4 signaling in macrophages interacting with HSCs during hepatic fibrosis.

Remifentanil modulates the TLR4‑mediated MMP‑9/TIMP1 balance and NF‑κB/STAT3 signaling in LPS‑induced A549 cells

Remifentanil is a widely used in general anesthetic that has been found to suppress the inflammatory response in aortic endothelial cells. Therefore, it was hypothesized that remifentanil can inhibit inflammatory dysfunction in lung epithelial cells to alleviate acute lung injury (ALI). The present study aimed to examine the effects of remifentanil on inflammatory injury, MMP-9/tissue inhibitor of metalloproteinase 1 (TIMP1) balance and the potential associated regulatory pathways in A549 cells. Lipopolysaccharide (LPS) was used to treat A549 cells to establish ALI models. The possible roles of different concentrations of remifentanil in cell viability was then determined by CCK-8 and Lactate dehydrogenase release assay. Apoptosis was assessed by flow cytometry analysis and western blotting. Inflammation and oxidative stress were measured by ELISA and corresponding kits respectively. Subsequently, the effects of remifentanil on Toll-like receptor 4 (TLR4) expression and the MMP-9/TIMP1 balance were assessed by western blotting and ELISA. In addition, the effects of remifentanil on NF-κB/STAT3 signaling were evaluated by measuring the protein expression levels of associated pathway components and the degree of NF-κB nuclear translocation using western blotting and immunofluorescence respectively. Remifentanil was found to increase cell viability whilst reducing apoptosis, inflammation and oxidative stress in the LPS-treated cells. In addition, TLR4 inhibitor CLI-095 suppressed MMP-9 expression and secretion while potentiating TIMP1 expression and secretion in LPS-challenged cells. Remifentanil treatment was able to modulate TLR4 to mediate LPS-induced MMP-9/TIMP1 imbalance and suppress the phosphorylation of NF-κB/STAT3 signaling components, in addition to inhibiting NF-κB nuclear translocation. Taken together, remifentanil downregulated TLR4 to reduce MMP-9/TIMP1 imbalance to inhibit inflammatory dysfunction in LPS-treated A549 cells, by regulating NF-κB/STAT3 signaling.

Ligustilide inhibits the proliferation of human osteoblastoma MG63 cells through the TLR4-ERK pathway

OBJECTIVE

To study the proapoptotic effect of ligustilide on osteoblastoma (OS) and the relative related molecular mechanism.

METHODS AND MATERIALS

An MTT was used to examine the proliferation of OS cells, and Flow cytometry was used to analyze apoptosis and the cell cycle. Western blotting was used to detect the signaling pathway of apoptosis, and immunohistochemical (IH) staining was used to detect the apoptosis status of OS cells. A TLR4 inhibitor was used to study the effect of ligustilide on OS.

RESULTS

Ligustilide inhibited OS cell proliferation but had no inhibitory effect on normal bone marrow cells. Flow cytometry results showed that ligustilide induced apoptosis in OS cells, and the cell cycle was arrested at the M/G2 phase. Western blot results showed that ERK, P53, P21, Caspase 9, Caspase 8 and Caspase 3 were all activated; cytochrome C and Bax increased; and Bcl-2 decreased when OS was treated with ligustilide. When an ERK or Caspase inhibitor was added to the culture medium, the apoptosis of OS cells decreased to some degree. When OS cells were pretreated with CLI-095, which is a TLR4 inhibitor, the percentage of apoptotic cells and cell cycle arrest were both reversed. IH results also showed that ligustilide induced apoptosis in OS cells, and the effect was blocked by the TLR4 inhibitor.

CONCLUSION

Ligustilide selectively inhibited the proliferation of OS cells by inducing apoptosis, which possibly included endogenous and exogenous apoptosis through TLR4.

Critical role of TLR4 in uncovering the increased rewarding effects of cocaine and ethanol induced by social defeat in male mice

BACKGROUND

Substance use disorders and social stress are currently associated with changes in the immune system response by which they induce a proinflammatory state in neurons and glial cells that eventually modulates the reward system.

AIMS

The aim of the present work was to assess the role of the immune TLR4 (Toll-like receptors 4) and its signaling response in the increased contextual reinforcing effects of cocaine and reinforcing effects of ethanol (EtOH) induced by social defeat (SD) stress.

METHODS

Adult male C57BL/6 J wild-type (WT) mice and mice deficient in TLR4 (TLR4-KO) were assigned to experimental groups according to stress condition (exploration or SD). Three weeks after the last SD, conditioned place preference (CPP) was induced by a subthreshold cocaine dose (1 mg/kg), while another set underwent EtOH 6% operant self-administration (SA). Several inflammatory molecules were analyzed in the hippocampus and the striatum.

RESULTS

SD induced higher vulnerability to the conditioned rewarding effects of cocaine only in defeated WT mice. Similarly, defeated WT mice exhibited higher 6% EtOH consumption, an effect that was not observed in the defeated TLR4-KO group. However, the motivation to obtain the drug was observed in both genotypes of defeated animals. Notably, a significant upregulation of the protein proinflammatory markers NFkBp-p65, IL-1β, IL-17 A and COX-2 were observed only in the defeated WT mice, but not in their defeated TLR4-KO counterparts.

CONCLUSIONS

These results suggest that TLR4 receptors mediate the neuroinflammatory response underlying the increase in the rewarding effects of cocaine and EtOH induced by social stress.

Sevoflurane-induced cognitive decline in aged mice: Involvement of toll-like receptors 4

Toll-like receptors 4 (TLR4) contributes to the pathogenesis of some neurodegenerative diseases. However, little is known about whether TLR4 is associated with sevoflurane-induced cognitive decline. This investigation aims to address the effect of global TLR4 gene knockout on cognitive decline following sevoflurane exposure to mice. Wild-type and TLR4^-/- mice were exposed to 3% sevoflurane. Novel object recognition test and Y-maze test were used to analyze cognitive function. Tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in plasma and hippocampus were measured by ELISA. Peripheral administration of recombinant TNF-α to TLR4^-/- mice was used to observed the role of TNF-α in cognitive function following sevoflurane. Our results showed that, in contrast to wild-type mice, TLR4 deficiency protected against the cognitive function impairment following sevoflurane exposure, and abrogated IL-1β, IL-6 and TNF-α response to sevoflurane in the system and the hippocampus. Subcutaneous administration of recombinant TNF-α elevated these cytokine levels in the hippocampus, and resulted in cognitive decline in TLR4^-/- mice exposed to sevoflurane. Taken together, our results identify the crucial role of TLR4 in sevoflurane-induced cognitive decline, and showed that TLR4 mediated pro-inflammatory cytokine response to sevoflurane, and consequent cognitive decline in aged mice exposed to sevoflurane, and imply a novel target for improvement and therapy of sevoflurane-associated cognitive decline.

Toll-like receptors as diagnostic targets in pellucid marginal degeneration

The main purpose of this study is to evaluate the diagnostic role of Toll-like receptors 2 (TLR2) and 4 (TLR4) expression in corneal and conjunctival epithelial cells of eyes with pellucid marginal degeneration (PMD) compared to keratoconus patients (KC) and control subjects. A prospective case-control study in 29 PMD eyes, 109 KC eyes and 72 healthy eyes was done. All participants were subjected to a clinical, topographic, aberrometric and tomographic exam with extraction of corneal and conjunctival epithelial cells through scraping. The TLR2 and TLR4 expression was measured with flow cytometry. Receiver operating characteristic (ROC) curve analysis was used to determine the most appropriate cutoff point for predicting the risk of PMD and KC. Correlations between TLR2/TLR4 expression and the severity of PMD/KC were evaluated. A TLRs follow-up review was made 19 ± 4 months after to the first review. As result, mean expression of TLR2 and TLR4 in both corneal and conjunctival epithelial cells was significantly higher in eyes with corneal ectasia (PMD and KC) than in control eyes (all p < 0.05). Conjunctival TLR4 expression showed the highest capacity to diagnose the existence of PMD (odd ratio 42.84; 95% confidence interval:6.20-296.20; p < 0.0001) after adjusting by eye rubbing and steeper corneal meridian. Moreover, we found an association between the TLR2/TLR4 overexpression with the severity of the PMD and KC measured by corneal topographic, aberrometric and tomographic quantitative parameters (all p < 0.05). Differences on TLR2/TLR4 expression between study groups were maintained during the follow-up period. In conclusion, the TLR2/TLR4 overexpression in corneal and conjunctival epithelial cells of PMD and KC patients compared to healthy control subjects have demonstrated their role as diagnostic target in both corneal ectatic disorders.

Acute glucose load induced islet β cells dysfunction in TLR4 dependent manner in male mice

Recent studies highlighted the significance of chronic inflammation, which is mediated in part by toll-like receptors 4 (TLR4), in islet β cell dysfunction by high-glucose exposure. However, about it is unclear whether islet β cell dysfunction in response to high glucose is associated with TLR4. This investigation was designed to address the effect of TLR4 deficiency on insulin secretion in mice in response to acute intravenous glucose load. Hyperglycemic clamp was used to impair insulin secretion, and intraperitoneal glucose tolerance test was carried out to analyze insulin secretion function of islet β cells. Our results showed that TLR4 deficiency repressed insulin secretion impairment in response to acute intravenous glucose load. Compared to wild-type mice, TLR4^-/- mice did not exhibit increase of IL-1β and TNF-α level in plasma and pancreatic tissue in response to acute intravenous load of high glucose. However, recombinant IL-1β or TNF-α administration restored insulin secretion impairment induced by high glucose in TLR4^-/- mice. Taken together, our results demonstrated that TLR4 activation and subsequent IL-1β and TNF-α production contribute to islet β cell dysfunction in mice in response to acute intravenous load of high glucose, which may provide a theoretical basis for diabetes complication improvement by physical exercise.

[Effects of TLR4-PI3K-Rac1 pathway on cytoskeleton rearrangement and phagocytosis of macrophage]

Objective: To investigate the effects of Toll-like receptor 4 (TLR4)-phosphatidylinositol 3-kinase (PI3K) -Ras-related C3 botulinum toxin 1 (Rac1) signaling pathway on macrophage cytoskeleton rearrangement and phagocytosis. Methods: Mouse macrophage cell line RAW264.7 was divided into blank group, negative control group and TLR4-RNA interference (RNAi) group. The lentivirus carrying TLR4 short hairpin RNA (shRNA) and nonsense control sequence were respectively transfected into TLR4-RNAi group and negative control group. The cells in blank group were not transfected. The silencing efficiency of TLR4 was detected by Western blot. Real-time fluorescence quantitative PCR was used to detect the expression of PI3K and Rac1 mRNA in each group. The expressions of PI3K, p-Rac1 and Rac1 protein were detected by Western blot. Cytoskeleton was observed by laser scanning confocal microscopy. Mean fluorescence intensity (MFI) and the percentage of cells phagocytosing flurescein inothiocyanate-labeled Eseherichina coli (FITC-E.coli) (Phagocytosed cell %) were detected by flow cytometry. Results: The RAW264.7 cells can be successfully transfected by TLR4-shRNA lentivirus, and the transfection efficiency ranged from 80% to 90%. The silencing efficiency of TLR4 gene was (63±4)%. After silencing the TLR4 gene, the relative expression of TLR4 mRNA and protein (0.20±0.03, 0.37±0.04), PI3K mRNA and protein (0.64±0.06, 0.75±0.06), Rac1 mRNA, protein and p-Rac1 protein (0.75±0.04, 0.76±0.01, 0.74±0.05) in TLR4-RNAi group were significantly lower than those in negative control group and blank group (all P<0.01). The change of cytoskeleton: after silencing the TLR4 gene, the celluar pseudopods were short and stiff, with the impaired capacity of phagocytosing FITC-E.coli. Cells in blank group and negative control group extended good pseudopodia, and the capacity of phagocytosing FITC-E.coli was normal. The MFI and Phagocytosed cells % of TLR4-RNAi group[(7 453±564), (70.20±2.27)%]were significantly lower than those in the blank group and the negative control group (all P<0.01). Positive correlations were existed between mRNA, protein expression of TLR4, PI3K, Rac1 and MFI, Phagocytosed cells% (all P<0.05) in all groups. Conclusion: TLR4-PI3K-Rac1 pathway involves in the cytoskeleton rearrangement and impairs the phagocytosis of macrophages.

[The effect of Toll-like receptor 4 in nicotine suppressing the osteogenic potential of periodontal ligament stem cells]

Objective To explore the impact of nicotine on proliferation and osteogenic capability of periodontal ligament stem cells (PDLSCs), and the role of Toll-like receptor 4 (TLR4) in nicotine, suppressing the osteogenic capability of PDLSCs. Methods PDLSCs were cultured in vitro, and the flow cytometer was used to identify the surface antigen markers of PDLSCs. WST-1 was used to detect the proliferation ability of PDLSCs, which were stimulated by different concentrations of nicotine. Alizarin red staining was used to observe the formation of mineralized nodules after PDLSCs stimulation with different concentrations of nicotine. Real-time polymerase chain reaction (RT-PCR) and Western blot were used to detect the change in osteogenic potential of PDLSCs stimulated by nicotine, after TAK-242, and with the inhibitor of TLR4. Results PDLSCs expressed mesenchymal stem cell-associated markers CD90 and CD105. When the concentration of nicotine was 10⁻⁴ mol·L⁻¹, the PDLSC proliferation could be suppressed after 3 d compared with the control group (P<0.05). The amount of mineralized nodules reduced after osteogenic differentiation at 21 d by alizarin red staining. RT-PCR and Western blot showed the expression levels of alkaline phosphatase (ALP), and osteocalcin (OCN), and the Runt-related transcription factor-2 (Runx-2) were lower than in the control group when nicotine suppressed the PDLSCs (P<0.05). This effect was attenuated after TAK-242 was added. Conclusion Nicotine suppresses the proliferation and osteogenic capability of PDLSCs, which may be regulated by TLR4.

Immunoregulatory Role of MicroRNA-21 in Macrophages in Response to Bacillus Calmette-Guerin Infection Involves Modulation of the TLR4/MyD88 Signaling Pathway

BACKGROUND/AIMS

The purpose of this study is to explore the immunoregulatory role of microRNA-21 (miR-21) targeting of the TLR4/MyD88 signaling pathway in macrophages in response to Bacillus Calmette-Guerin (BCG) infection.

METHODS

After infection with BCG, mouse RAW246.7 cells were assigned into control, BCG, miR-21 mimic + BCG, mimic-negative control (NC) + BCG, miR-21 inhibitor + BCG, inhibitor-NC + BCG, BCG + TAK242 (an inhibitor of the TLR4 signaling pathway), and miR-21 inhibitor + TAK242 + BCG groups. Western blotting and qRT-PCR were used to detect the expression of miR-21, TLR4 and MyD88. The levels of TNF-a, IL-6 and IL-10 were detected by enzyme-linked immunosorbent assay (ELISA). Cell viability was measured using an MTT assay. Cell apoptosis and necrosis rates were detected using flow cytometry.

RESULTS

Compared with the control group, miR-21 expression and levels of TNF-a, IL-6 and IL-10, as well as cell apoptosis and necrosis rates, were elevated, while expression of TLR4 and MyD88, as well as cell viability, were reduced in BCG infection groups. Compared with the BCG group, miR-21 expression was increased in the miR-21 mimic + BCG group but decreased in the miR-21 inhibitor + BCG and miR-21 inhibitor + TAK242 + BCG groups. The expression of TLR4 and MyD88, as well as the cell viability, were decreased, while levels of TNF-a, IL-6 and IL-10, as well as cell apoptosis and necrosis rates, were increased in the miR-21 mimic + BCG and TAK242 + BCG groups. The opposite trends were found in the miR-21 inhibitor + BCG group. Compared with the TAK242 + BCG group, the miR-21 inhibitor + TAK242 + BCG group had higher expression of TLR4 and MyD88 as well as higher cell viability and lower levels of TNF-a, IL-6, IL-10, cell apoptosis and necrosis rates. However, the miR-21 inhibitor + TAK242 + BCG group exhibited the opposite trends when compared with the miR-21 inhibitor + BCG group.

CONCLUSION

Our results suggest that miR-21 can negatively modulate the TLR4/MyD88 signaling pathway, resulting in decreased cell viability, increased cell apoptosis and increased levels of inflammatory factors following BCG infection in macrophages.

Lipopolysaccharide activated TLR4/NF-κB signaling pathway of fibroblasts from uterine fibroids

Uterine fibroids (UF) are the most common benign tumor of the female reproductive tract. The aim of this study was to explore the role of lipopolysaccharide (LPS)-induced activation of TLR4/NF-κB signaling pathway on stromal fibroblasts in the pathogenesis of UF. Here, TLR4/NF-κB signaling pathway was more activated in UF, and UF cells (UFC) and UF derived fibroblasts (TAF) than in smooth muscle tissues, smooth muscle cell (SMC) and myometrial fibroblasts (fib) respectively. After lipopolysaccharide (LPS) stimulation, the activity of fib was enhanced, characterized by the increased expression of fibroblast activation protein (FAP), and increased secretion of collagen I and transforming growth factor-β (TGF-β). Moreover, TLR4 inhibitor (VIPER) and siTLR4 can represses LPS-activated fibroblasts and TLR4/NF-κB signaling transduction pathways in fib and UFC cells. Co-cultured with LPS-activated fibroblast enhanced fibroblast activation and TLR4/NF-κB signaling. In conclusion, LPS treatment activated TLR4/NF-κB signaling pathway on fibroblasts, which may involve in the development of UF. Our study indicated reproductive tract infection may be associated with fibroid pathogenesis through TLR4/NF-κB signaling. Targeting NF-κB with inhibitors may hold promises of treating uterine fibroid.

Amelioration of experimentally induced diabetic nephropathy and renal damage by nilotinib

Diabetes mellitus is an ever growing world-wide health problem. The patient has to stick to a firm life-long therapeutic regimen, otherwise diabetic complications will develop. Diabetic nephropathy (DN) is one of the most common diabetic complications and it requires careful medical attendance. Nilotinib hydrochloride is a protein tyrosine kinase inhibitor reported to have numerous therapeutic efficacies besides being an anticancer. In the current study, single I.P. streptozotocin (50 mg/kg) injection was used to induce type I diabetes mellitus in male Sprague-Dawley rats. After 8 weeks, significant deterioration of renal function with urinary excretion of nephrin, podocalyxin, and albumin was observed. Daily oral administration of nilotinib (20 mg/kg) for 8 weeks significantly improved signs of DN on all investigated scales. On a biochemical scale, kidney functions, albuminuria, urinary nephrin, podocalyxin excretion, and host oxidant/antioxidant balance significantly improved. Kidney content of nitric oxide, expression of toll-like receptors 4 and NF-κB/p65 activity significantly declined as well. On a histopathological scale, α-smooth muscle actin and nestin expression significantly declined. Meanwhile, area of fibrosis significantly declined as seen with significant reduction in accumulation of extracellular matrix components and kidney content of collagen. Ultimately, such improvements were accompanied by significant restoration of normal kidney physiology and function. In conclusion, nilotinib can hinder progression of DN through various mechanisms. Reduction of oxidative stress, enhancement of host antioxidant defense system, reduction of inflammation, angiogenesis, tissue hypoxia, and pro-fibrogenic biomarker expression can be implicated in the beneficial therapeutic outcome observed with nilotinib therapy.

Toll-like receptor expression and signaling in human diabetic wounds

AIM: To examine the contribution of toll-like receptors (TLRs) expression and activation to the prolonged inflammation often seen in human diabetic wounds.

METHODS: Debridement wound tissue was collected from diabetic patients with informed consent. Total RNA and protein were isolated and subjected to real-time polymerase chain reaction and Western blot analyses.

RESULTS: TLR1, 2, 4, and 6 mRNA expressions were increased significantly in wounds of diabetic patients compared with non-diabetic wounds (P < 0.05). MyD88 protein expression was significantly increased in diabetic wounds compared to non-diabetic wounds. Interleukin-1beta, tumor necrosis factor-alpha concentration nuclear factor-kappa B activation, and thiobarbituric acid reactive substances were increased in diabetic wounds compared to non-diabetic wounds (P < 0.01).

CONCLUSION: Collectively, our novel findings show that increased TLR expression, signaling, and activation may contribute to the hyper inflammation in the human diabetic wounds.