Low concentration of lipopolysaccharide acts on MC3T3-E1 osteoblasts and induces proliferation via the COX-2-independent NFκB pathway

The replication of spring viraemia of carp virus can be regulated by reactive oxygen species and NF-κB pathway

Different viruses could induced ROS generation to alter intracellular redox state in the host cells, and unbalanced redox state was suggested to have various effects on viral replication. In this study, we investigated the influence of reactive oxygen species (ROS) on replication of spring viraemia of carp virus (SVCV) in fish cells. After SVCV infection, there existed a time-dependent increase in ROS generation. The present results revealed that antioxidant N-acetyl-l-cysteine (NAC) resulted in a lower ROS levels and increased SVCV replication in EPC cell. In contrast, a GSH synthesis inhibitor buthionine sulfoximine (BSO) induced ROS generation and decreased SVCV replication. In addition, activation of NF-κB suppressed SVCV replication by using two inhibitors of cytokine-induced IκBα phosphorylation. More importantly, enhancement of the activity of NF-κB was found in BSO treatment, which indicated that dropped SVCV replication likely occurred via ROS activation of NF-κB. Overall, our results revealed that the SVCV infection and replication could generate ROS and be affected by the redox state, where this progression was associated with the alteration in NF-κB pathway induced by oxidative stress.

Mechanical stretch regulates microRNA expression profile via NF-κB activation in C2C12 myoblasts

MicroRNAs (miRNAs/miRs) and nuclear factor (NF)-κB activation are involved in mechanical stretch-induced skeletal muscle regeneration. However, there are a small number of miRNAs that have been reported to be associated with NF‑κB activation during mechanical stretch-induced myogenesis. In the present study, C2C12 myoblasts underwent cyclic mechanical stretch in vitro, to explore the relationship between miRNA expression and NF‑κB activation during stretch-mediated myoblast proliferation. The results revealed that 10% deformation, 0.125 Hz cyclic mechanical stretch could promote myoblast proliferation. The miRNA expression profile was subsequently altered; miR‑500, ‑1934, ‑31, ‑378, ‑331 and ‑5097 were downregulated, whereas miR‑1941 was upregulated. These miRNAs were all involved in stretch‑mediated myoblast proliferation. Notably, the expression of these miRNAs was reversed following treatment of 0.125 Hz mechanically stretched C2C12 cells with NF‑κB inhibitors, which was accompanied by C2C12 cell growth suppression. Therefore, the present study is the first, to the best of our knowledge, to demonstrate that the NF‑κB‑dependent miRNA profile is associated with mechanical stretch-induced myoblast proliferation.

Hepatocyte growth factor-induced differentiation of bone mesenchymal stem cells toward hepatocyte-like cells occurs through nuclear factor-kappa B signaling in vitro

Hepatocyte growth factor (HGF) is multifaceted cytokine that regulates proliferation, differentiation, morphology, and motility within numerous stem cells. More recently, HGF has been reported to induce the differentiation of bone mesenchymal stem cells (BMSCs) into mature hepatocytes, but the underlying biochemical and molecular signaling is largely unknown. We isolated BMSC from the bone marrow of rats, which were then cultured and exposed to HGF for 15 days. We subsequently assayed these cells for liver functionality and markers, and blocked NF-кB signaling at various stages of the pathway. The present results demonstrate that HGF induces the differentiation of BMSCs toward hepatocyte-like cells through the NF-кB signaling. More specifically, HGF upregulated the translocation of NF-кB to the nucleus.

Hyperoside exerts anti-inflammatory and anti-arthritic effects in LPS-stimulated human fibroblast-like synoviocytes in vitro and in mice with collagen-induced arthritis

AIM

Hyperoside is a flavonol glycoside mainly found in plants of the genera Hypericum and Crataegus, which has shown anti-oxidant, anti-cancer and anti-inflammatory activities. In this study, we investigated the effects of hyperoside on human rheumatoid fibroblast-like synoviocytes (FLSs) in vitro and on mouse collagen-induced arthritis (CIA) in vivo.

METHODS

FLSs were isolated from primary synovial tissues obtained from rheumatoid arthritis (RA) patients and exposed to LPS (1 μg/mL). Cell viability and proliferation were measured with MTT and BrdU assay. Cell migration was assessed using wound-healing assay and Transwell assay. DNA binding of NF-κB was measured using a TransAM-NFkappaB kit. The localization of p65 subunit was detected with immunocytochemistry. CIA was induced in mice by primary immunization with Bovine Type II collagen (CII) emulsified in CFA, followed by a booster injection 3 weeks later. The arthritic mice were treated with hyperoside (25, 50 mg·kg(-1)·d(-1), ip) for 3 weeks, and the joint tissues were harvested for histological analysis.

RESULTS

Hyperoside (10, 50, 100 μmol/L) dose-dependently inhibited LPS-induced proliferation and migration of human RA FLSs in vitro. Furthermore, hyperoside decreased LPS-stimulated production of TNF-α, IL-6, IL-1 and MMP-9 in the cells. Moreover, hyperoside inhibited LPS-induced phosphorylation of p65 and IκBα, and suppressed LPS-induced nuclear translocation of p65 and DNA biding of NF-κB in the cells. Three-week administration of hyperoside significantly decreased the clinical scores, and alleviated synovial hyperplasia, inflammatory cell infiltration and cartilage damage in mice with CIA.

CONCLUSION

Hyperoside inhibits LPS-induced proliferation, migration and inflammatory responses in human RA FLSs in vitro by suppressing activation of the NF-κB signaling pathway, which contributes to the therapeutic effects observed in mice with CIA.

Renal interstitial fibrosis induced by high-dose mesoporous silica nanoparticles via the NF-κB signaling pathway

Previous studies have indicated that the nephrotoxicity induced by mesoporous silica nanoparticles (MSNs) is closely related to inflammation. Nuclear factor kappa B (NF-κB), a common rapid transcription factor associated with inflammation, plays an important role in the process of many kidney diseases. Acute toxicity assessment with a high-dose exposure is critical for the development of nanoparticle, as a part of standardized procedures for the evaluation of their toxicity. The present study was undertaken to observe the acute toxicity, predict the potential target organs of MSNs injury, and test the hypothesis that the NF-κB pathway plays a role in mediating the acute kidney injury and renal interstitial fibrosis in mice induced by MSNs. Balb/c mice were intraperitoneally injected with MSNs at concentrations of 150, 300, or 600 mg/kg. All of the animals were euthanized 2 and 12 days after exposure, and the blood and kidney tissues were collected for further studies. In vitro, the cytotoxicity, fibrosis markers, and NF-κB pathway were measured in a normal rat kidney cell line (NRK-52E). Acute kidney injury was induced by MSNs in mice after 2 days, some renal tubules regenerated and renal interstitial fibrosis was also observed. The expression of fibrosis markers and the nuclear translocation of NF-κB p65 in the kidney homogenates increased after exposure to MSNs. The in vitro study showed that MSNs cause cytotoxicity in NRK-52E cells and increased the expression of fibrosis markers. In addition, the NF-κB pathway could be induced, and inhibition of the NF-κB pathway could alleviate the fibrosis caused by MSNs. We conclude that inflammation is a major effector of the acute kidney toxicity induced by MSNs and results in renal interstitial fibrosis, which is mediated by the NF-κB signaling pathway.

Low-level diode laser therapy reduces lipopolysaccharide (LPS)-induced bone cell inflammation

In this study, the aim is to investigate the cytologic effects of inflammatory bone cells after in vitro low-level laser therapy (LLLT). A human osteosarcoma cell line (MG63) was cultured, infected with lipopolysaccharide (LPS) and exposed to low-level laser treatment at 5 or 10 J/cm(2) using a 920 nm diode laser. MG63 cell attachment was observed under a microscope, and cell viability was quantified by mitochondrial colorimetric assay (MTT). LPS-treated MG63 cells were irradiated with LLLT, and the inflammatory markers iNOS, TNF-α and IL-1, were analyzed by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. The data were collected and analyzed by one-way analysis of variance (ANOVA); p < 0.05 indicated a statistically significant difference. Low-level laser treatment on MG63 cells increased their ability to attach and survive. After irradiation, the expression levels of iNOS, TNF-α and IL-1 in LPS-infected MG63 cells decreased over time (p < 0.05).

CONCLUSIONS

low-level diode laser treatment increased the MG63 cell proliferative ability and decreased the expression of inflammatory mediators in MG63 cells.

Variation in the Cox-2 Gene May Modify the Effect of Alendronate on Vertebral Fracture Prevention

Bisphosphonates such as alendronate, which are potent specific inhibitors of osteoclast-mediated bone resorption, are widely used for treatment of postmenopausal osteoporosis as well as other diseases related to bone remodeling. We evaluated whether the reportedly functional PTGS2 (prostaglandin-endoperoxide synthase 2/cyclooxygenase [COX] 2) genotypes influence the efficacy of alendronate on vertebral fracture prevention. Sixty postmenopausal osteoporotic women participated in this interventional study. The extent of vertebral fracture was evaluated in all participants before and after intervention using X-ray imaging. Alendronate (10mg/day), calcium (1gr/day) and vitamin D (400mg/day) were given to participants for 2 years. Laboratory measurements included circulating crosslaps, osteocalcin, PTH, osteoporotegrin, RANKL, vitamin D, TNF-α, IL-6, IL-1 levels. Hip and spine BMD (bone mass density) were measured using DEXA. Genotyping for cox-2 gene SNP (−765G/C) was performed using PCR- RFLP method. Genotype frequency of homozygous major allele (GG), heterozygous (GC) and homozygous minor allele (CC) were 61.7%, 33.3% and 5% respectively. Evaluation of vertebral fracture before alendronate therapy in participants demonstrated no significant difference between carriers of G and C alleles, although the difference appeared near to significant after alendronate therapy at the end of 2 years. Serum PTH level and L2-L4 BMD were significantly different between subjects with different alleles. Moreover, IL-1 had prominently higher concentration in C allele carries. Furthermore, there was a significant difference in terms of the extent of vertebral fracture between two allelic groups after two years of treatment. Since bone remodeling process has been proved to be affected by inflammatory factors; it appears that variation in COX-2 genotypes may influence alendronate efficacy in fracture prevention among postmenopausal osteoporotic women.