Nuclear Factor kappa-B Ligand Signaling Research Articles

MicroRNA-363-3p/sphingosine-1-phosphate receptor 1 axis inhibits sepsis-induced acute lung injury via the inactivation of nuclear factor kappa-B ligand signaling.

Infection-associated inflammation and coagulation are critical pathologies in sepsis-induced acute lung injury (ALI). This study aimed to investigate the effects of microRNA-363-3p (miR-363-3p) on sepsis-induced ALI and explore the underlying mechanisms. A cecal ligation and puncture-induced septic mouse model was established. The results of this study suggested that miR-363-3p was highly expressed in lung tissues of septic mice. Knockdown of miR-363-3p attenuated sepsis-induced histopathological damage, the inflammation response and oxidative stress in lung tissues. Furthermore, knockdown of miR-363-3p reduced the formation of platelet-derived microparticles and thrombin generation in blood samples of septic mice. Downregulation of miR-363-3p suppressed sphingosine-1-phosphate receptor 1 (S1PR1) expression in lung tissues and subsequently inactivated the nuclear factor kappa-B ligand (NF-κB) signaling. A luciferase reporter assay confirmed that miR-363-3p directly targeted the 3’-untranslated region of the mouse S1pr1 mRNA. Collectively, our study suggests that inactivation of NF-κB signaling is involved in the miR-363-3p/S1PR1 axis-mediated protective effect on septic ALI.

Effect of MicroRNA-26a Targeting mCTGF on Calcification of Vascular Smooth Muscle Cells Through Regulating Osteoprotegerin/Receptor Activator of NF-kB/Receptor Activator of Nuclear Factor Kappa-B Ligand Signaling Pathway

To explore the effect of microRNA-26a targeting mCTGF on inhibiting the calcification of vascular smooth muscle cells (VSMCs) through OPG/RANK/RANKL signaling pathway. VSMCs were isolated and cultured by adherent method. The morphology of VSMCs was observed under microscope and the surface antigen was identified by flow cytometry. The calcification of VSMCs was detected using alizarin red S staining and oil red O staining. microRNA-26a level in supernatant of cultured VSMCs was detected by ultracentrifugation method. The binding site between microRNA-26a and 3′-UTR of mCTGF was predicted by bioinformatics software; VSMCs were induced to be calcified and verified by the luciferase reporter gene assay. The mRNA and protein expressions of OPG/RANK/RANKL signaling pathway were measured by qRT-PCR and Western blotting. Normal VSMCs were assigned into normal group (normal VSMCs were treated with the exosomes secreted by normal VSMCs), CKD group (normal VSMCs were treated with the exosomes secreted by VSMCs in mice with chronic kidney disease (CKD)) and CKD/overexpressed mCTGF group (normal VSMCs were treated with the exosomes secreted by VSMCs in CKD mice and meanwhile treated with overexpressed mCTGF) followed by analysis of OPG/RANK/RANKL signaling level by qRT-PCR and ALP activity. VSMCs grew against the wall and showed a long fusiform shape. Calcification and adipogenesis of VSMCs was found under different induction conditions. microRNA-26a level in the supernatant of VSMCs in CKD group was significantly higher than normal group; after microRNA-26a bound to of mCTGF, mCTGF level in the CKD/overexpressed mCTGF group was significantly lower. The expression of OPG/RANK/RANKL signaling pathway was significantly decreased in the CKD/overexpressed mCTGF group. Meanwhile, OPG/RANK/RANKL signaling protein was increased significantly after treatment of exosomes secreted by VSMCs in CKD mice. mCTGF is the target gene of microRNA-26a and microRNA-26a can target mCTGF to regulate exosomes secretion by VSMCs and OPG/RANK/RANKL signaling to inhibit the calcification of VSMCs.

Efficiency of Estrogen Replacement Therapy in Osteoporosis

Estrogen therapy has been taken as a settled approach for both prevention and treatment of osteoporosis, especially in post-menopausal women as well as for the treatment of symptoms associated with menopause. Recent studies suggest that nuclear factor kappa-B ligand/receptor activator of nuclear factor kappa-B/osteoprotegerin system plays a signi cant role in osteoclastic activity regulation, with receptor activator of nuclear factor kappa-B ligand signaling in the presence of macrophage colony stimulating factor leading to increase in osteoclastic differentiation and functioning while osteoprotegerin neutralizing receptor activator of nuclear factor kappa-B ligand. Estrogen acts by increasing osteoprotegerin levels, and decreasing macrophage colony stimulating factor and receptor activator of nuclear factor kappa-B, thereby reducing bone resorption. Furthermore, estrogen is also known to be causing increased calcium absorption through gut and kidneys. The use of estrogen therapy in patients of osteoporosis is also considered to be highly cost effective. On the negative side, studies have shown that oral estrogen therapy can lead to complications like cholelithiasis, thrombophlebitis and pulmonary embolism, the most detrimental being endometrial cancer. But studies have shown that it can be virtually eliminated with the addition of progesterone in the cyclic combined regimen. Majority of bene cial effects occur with long term use of estrogen therapy, but the compliance by most of women appears to be poor and is usually due to lack of awareness, misconceptions, advice of physician and phobia of side effects. Additional studies should therefore be conducted to evaluate in detail the causes of non-compliance and strategies to improve compliance. The bene t of quality of life improvement with estrogen therapy should be taken into account and further evaluated via studies.

Vitamin E as an Antiosteoporotic Agent via Receptor Activator of Nuclear Factor Kappa-B Ligand Signaling Disruption: Current Evidence and Other Potential Research Areas

Osteoporosis is a growing healthcare burden that affects the quality of life in the aging population. Vitamin E is a potential prophylactic agent that can impede the progression of osteoporosis. Various in vivo studies demonstrated the antiosteoporotic potential of vitamin E, but evidence on its molecular mechanism of action is limited. A few in vitro studies showed that various forms of vitamin E can affect the receptor activator of nuclear factor kappa-B ligand (RANKL) signaling and their molecular targets, thus preventing the formation of osteoclasts in the early stage of osteoclastogenesis. Various studies have also shown that the effects of the different isoforms of vitamin E differ. The effects of single isoforms and combinations of isoforms on bone metabolism are also different. Vitamin E may affect bone metabolism by disruption of free radical-mediated RANKL signaling, by its oestrogen-like effects, by its effects on the molecular mechanism of bone formation, by the anti-inflammatory effects of its long-chain metabolites on bone cells, and by the inhibition of 3-hydroxyl-3-methyglutaryl coenzyme A (HMG-CoA). In conclusion, the vitamin E isoforms have enormous potential to be used as prophylactic and therapeutic agents in preventing osteoporosis, but further studies should be conducted to elucidate their mechanisms of action.

PPAR-γ regulates osteoclastogenesis in mice

Osteoclasts are bone-resorbing cells derived from hematopoietic precursors of the monocyte-macrophage lineage. Regulation of osteoclast function is central to the understanding of bone diseases such as osteoporosis, rheumatoid arthritis and osteopetrosis. Although peroxisome proliferator-activated receptor-gamma (PPAR-gamma) has been shown to inhibit osteoblast differentiation, its role, if any, in osteoclasts is unknown. This is a clinically crucial question because PPAR-gamma agonists, "such as thiazolidinediones-" a class of insulin-sensitizing drugs, have been reported to cause a higher rate of fractures in human patients. Here we have uncovered a pro-osteoclastogenic effect of PPAR-gamma by using a Tie2Cre/flox mouse model in which PPAR-gamma is deleted in osteoclasts but not in osteoblasts. These mice develop osteopetrosis characterized by increased bone mass, reduced medullary cavity space and extramedullary hematopoiesis in the spleen. These defects are the result of impaired osteoclast differentiation and compromised receptor activator of nuclear factor-kappaB ligand signaling and can be rescued by bone marrow transplantation. Moreover, ligand activation of PPAR-gamma by rosiglitazone exacerbates osteoclast differentiation in a receptor-dependent manner. Our examination of the underlying mechanisms suggested that PPAR-gamma functions as a direct regulator of c-fos expression, an essential mediator of osteoclastogenesis. Therefore, PPAR-gamma and its ligands have a previously unrecognized role in promoting osteoclast differentiation and bone resorption.

Pathogenesis of psoriatic arthritis.

Psoriatic arthritis is an inflammatory arthritis associated with psoriasis that is more common and severe than initially appreciated. The success of biologic agents in psoriatic arthritis has sparked great interest in this disorder, although the disease pathogenesis is poorly understood. This review focuses on recent advances in the genetic factors and immune pathways that have been implicated in susceptibility to disease. In addition, recent studies examining the mechanisms that underlie angiogenesis, enthesitis, and bone resorption in psoriatic arthritis are discussed. Studies performed on several different populations indicate that the MHC class I allele Cw6 is associated with both early-onset psoriasis and psoriatic arthritis. Mutations in the caspase-activating recruitment domain 15 locus on chromosome 16 are also associated with psoriatic arthritis, providing support for a model involving innate immune mechanisms. Evidence for a CD8 antigen-driven acquired immune response in psoriatic synovium and blood was reported. The finding of elevated levels of vascular endothelial growth factor and angiopoietin 2 in psoriatic arthritis synovial vasculature may provide insights into events responsible for the tortuous vessel morphology, a histologic feature characteristic of psoriatic joints. Tumor necrosis factor (TNF)-alpha is a critical factor mediating inflammation in the synovium, enthesis, and bone. In particular, osteoclasts resorb bone via a receptor activator of nuclear factor kappaB-receptor activator of nuclear factor kappaB ligand signaling pathway that is potentiated by TNF-alpha. The lessening of bone marrow edema after anti-TNF therapy provides further support for the importance of this cytokine in disease pathogenesis. Recent studies provide additional support for distinct pathogenetic mechanisms in psoriatic arthritis that arise from a complex interplay between genetic and environmental factors. Histopathologic data and results from clinical trials highlight the predominance of TNF-mediated inflammation in psoriatic joint tissues.