Since their discovery, matrix vesicles (MVs) containing minerals have received considerable attention for their role in the mineralization of bone, dentin and calcified cartilage. Additionally, MVs' association with collagen fibrils, which serve as the scaffold for calcification in the organic matrix, has been repeatedly highlighted. The primary purpose of the present study was to establish a MVs–mimicking model (PEG-S-ACP/micelle) in vitro for studying the exact mechanism of MVs-mediated extra/intra fibrillar mineralization of collagen in vivo. In this study, high-concentration serine was used to stabilize the amorphous calcium phosphate (S-ACP), which was subsequently mixed with polyethylene glycol (PEG) to form PEG-S-ACP nanoparticles. The nanoparticles were loaded in the polysorbate 80 micelle through a micelle self-assembly process in an aqueous environment. This MVs–mimicking model is referred to as the PEG-S-ACP/micelle model. By adjusting the pH and surface tension of the PEG-S-ACP/micelle, two forms of minerals (crystalline mineral nodules and ACP nanoparticles) were released to achieve the extrafibrillar and intrafibrillar mineralization, respectively. This in vitro mineralization process reproduced the mineral nodules mediating in vivo extrafibrillar mineralization and provided key insights into a possible mechanism of biomineralization by which in vivo intrafibrillar mineralization could be induced by ACP nanoparticles released from MVs. Also, the PEG-S-ACP/micelle model provides a promising methodology to prepare mineralized collagen scaffolds for repairing bone defects in bone tissue engineering. 相似文献
One criterion for microRNA identification is based on their conservation across species, and prediction of miRNA targets by empirical approaches using computational analysis relies on the presence of conservative mRNA 3′UTR. Because most miRNA target sites identified are highly conserved across different species, it is not clear whether miRNA targeting is species-specific. To predict miRNA targeting, we aligned all available fibronectin 3′UTRs and observed significant conservation of all 20 species. Twelve miRNAs were predicted to target most fibronectin 3′UTRs, but rodent fibronectin showed potential binding sites specific for five different miRNAs. One of them, the miR-378a-5p, contained a complete matching seed-region for all rodent fibronectin, which could not be found in any other species. We designed experiments to test whether the species-specific targeting possessed biological function and found that expression of miR-378a-5p decreased cancer cell proliferation, migration, and invasion, resulting in inhibition of tumor growth. Silencing fibronectin expression produced similar effects as miR-378a-5p, while transfection with a construct targeting miR-378-5p produced opposite results. Tumor formation assay showed that enhanced expression of fibronectin in the stromal tissues as a background environment suppressed tumor growth, while increased fibronectin expression inside the tumor cells promoted tumor growth. This was likely due to the different signaling direction, either inside-out or outside-in signal. Our results demonstrated that species-specific targeting by miRNA could also exert functional effects. Thus, one layer of regulation has been added to the complex network of miRNA signaling. 相似文献
Ecosystems - Vegetation restoration can dramatically affect soil carbon (C), nitrogen (N) pools and microbial communities. Yet, it is uncertain what effects of vegetation restoration have on... 相似文献
Science China Life Sciences - Diabetic cardiomyopathy (DCM) is a common complication in diabetic patients. The molecular mechanisms of DCM remain to be fully elucidated. The intronic long noncoding... 相似文献
Necrotizing enterocolitis (NEC) is one of the most widespread and devastating gastrointestinal diseases in neonates. Destruction of the intestinal barrier is the main underlying cause of NEC. The aim of this study was to determine the role of lactadherin in preventing NEC in a neonatal rat model and investigate the molecular mechanism of lactadherin-mediated protection of the intestinal barrier. Neonatal rats were divided into three groups: dam feeding (DF), NEC (NEC), and NEC supplemented with 10 μg/(g·day) recombinant human lactadherin (NEC+L). Intestinal permeability, tissue damage, and cell junction protein expression and localization were evaluated. We found that lactadherin reduced weight loss caused by NEC, reduced the incidence of NEC from 100% to 46.7%, and reduced the mean histological score for tissue damage to 1.40 compared with 2.53 in the NEC group. Intestinal permeability of lactadherin-treated rats was significantly reduced when compared with that of the NEC group. In addition, the expression levels of JAM-A, claudin 3, and E-calcium in the ileum of NEC group animals increased compared with those in the ileum of DF group animals, and these levels decreased in the NEC+L group. Lactadherin changed the localization of claudin 3, occludin, and E-cadherin in epithelial cells. The mechanism underlying lactadherin-mediated protection of the intestinal barrier might be restoring the correct expression levels and localization of tight junction and adherent junction proteins. These findings suggest a new candidate agent for the prevention of NEC in newborns. 相似文献
Diabetic cognitive impairment (DCI) is a common diabetic complication with hallmarks of loss of learning ability and disorders of memory and behavior. Glucocorticoid receptor (GR) dysfunction is a main reason for neuronal impairment in brain of diabetic patients. Here, we determined that ipriflavone (IP) a clinical anti‐osteoporosis drug functioned as a non‐steroidal GR antagonist and efficiently ameliorated learning and memory dysfunction in both type 1 and 2 diabetic mice. The underlying mechanism has been intensively investigated by assay against the diabetic mice with GR‐specific knockdown in the brain by injection of adeno‐associated virus (AAV)‐ePHP‐si‐GR. IP suppressed tau hyperphosphorylation through GR/PI3K/AKT/GSK3β pathway, alleviated neuronal inflammation through GR/NF‐κB/NLRP3/ASC/Caspase‐1 pathway, and protected against synaptic impairment through GR/CREB/BDNF pathway. To our knowledge, our work might be the first to expound the detailed mechanism underlying the amelioration of non‐steroidal GR antagonist on DCI‐like pathology in mice and report the potential of IP in treatment of DCI. 相似文献
The H1N1 influenza virus causes acute respiratory tract infection, and its clinical symptoms are very similar to those of ordinary influenza. The disease develops rapidly. If the flu is not treated, complications such as pneumonia, respiratory failure, and multiple organ damage can occur, resulting in a high fatality rate. Influenza virus mutates rapidly. At present, there is no specific drug for H1N1, so it is an urgent need for clinical care to find new drugs to treat H1N1.
Materials and methods
The polysaccharide derived from Durvillaea Antarctica green algae has a certain antiviral effect. In this study, the results of CCK-8, apoptosis cycle detection, JC-1 and Western blotting proved that Duvira Antarctic polysaccharide (DAPP) has the ability to inhibit H1N1 infection.
Results
CCK-8 test showed that the DAPP with concentration at 32 μg/mL had no toxicity to MDCK cells. In addition, DAPP reduced cell apoptosis by inhibiting the ERK signaling pathway. Meanwhile, DAPP could increase the expression of STAT3 and significantly inhibited proinflammatory cytokines.
Conclusions
In summary, these results suggested that DAPP may be potential with the ability to resist the H1N1 influenza virus.
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Clostridium novyi(C.novyi)is a spore-forming anaerobic bacterium and opportunistic pathogen causing severe infectious diseases in humans and animal... 相似文献