Rod-like Cellulose Regenerated by Bottom-Up Assembly in Natural Rubber Latex and Its Reinforcement.

As a renewable biomass material, nano-cellulose has been investigated as a reinforcing filler in rubber composites but has seen little success because of its strong inclination towards aggregating. Here, a bottom-up self-assembly approach was proposed by regenerating cellulose crystals from a mixture of cellulose solution and natural rubber (NR) latex. Different co-coagulants of both cellulose solution and natural rubber latex were added to break the dissolution equilibrium and in-situ regenerate cellulose in the NR matrix. The SEM images showed that the sizes and morphologies of regenerated cellulose (RC) varied greatly with the addition of different co-coagulants. Only when a 5 wt% acetic acid aqueous solution was used, the RC particles showed an ideal rod-like structure with small sizes of about 100 nm in diameter and 1.0 µm in length. The tensile test showed that rod-like RC (RRC)-endowed NR vulcanizates with pronounced reinforcement had a drastic upturn in stress after stretching to 200% strain. The results of XRD and the Mullins effect showed that this drastic upturn in stress was mainly attributed to the formation of rigid RRC-RRC networks during stretching instead of the strain-induced crystallization of NR. This bottom-up approach provided a simple way to ensure the effective utilization of cellulosic materials in the rubber industry.

Role of ferroptosis-related genes in periodontitis based on integrated bioinformatics analysis.

BACKGROUND: Cell survival or death is one of the key scientific issues of inflammatory response. To regulate cell death during the occurrence and development of periodontitis, various forms of programmed cell death, such as pyroptosis, ferroptosis, necroptosis, and apoptosis, have been proposed. It has been found that ferroptosis characterized by iron-dependent lipid peroxidation is involved in cancer, degenerative brain diseases and inflammatory diseases. Furthermore, NCOA4 is considered one of ferroptosis-related genes (FRGs) contributing to butyrate-induced cell death in the periodontitis. This research aims to analyze the expression of FRGs in periodontitis tissues and to explore the relationship between ferroptosis and periodontitis. METHOD: Genes associated with periodontitis were retrieved from two Gene Expression Omnibus datasets. Then, we normalized microarray data and removed the batch effect using the R software. We used R to convert the mRNA expression data and collected the expression of FRGs. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), transcription factor (TF) and protein-protein interaction (PPI) network analyses were used. In addition, we constructed a receiver operating characteristic curve and obtained relative mRNA expression verified by quantitative reverse-transcription polymerase chain reaction (PCR). RESULTS: Eight and 10 FRGs related to periodontitis were upregulated and downregulated, respectively. GO analysis showed that FRGs were enriched in the regulation of glutathione biosynthetic, glutamate homeostasis, and endoplasmic reticulum-nucleus signaling pathway. The top TFs included CEBPB, JUND, ATF2. Based on the PPI network analysis, FRGs were mainly linked to the negative regulation of IRE1-mediated unfolded protein response, regulation of type IIa hypersensitivity, and regulation of apoptotic cell clearance. The expression levels of NCOA4, SLC1A5 and HSPB1 using PCR were significantly different between normal gingival samples and periodontitis samples. Furthermore, the diagnostic value of FRGs for periodontitis were "Good". CONCLUSIONS: We found significant associations between FRGs and periodontitis. The present study not only provides a new possible pathomechanism for the occurrence of periodontitis but also offers a new direction for the diagnosis and treatment of periodontitis.

Vestigial-Like 3 Plays an Important Role in Osteoblast Differentiation by Regulating the Expression of Osteogenic Transcription Factors and BMP Signaling.

Our previous gene profiling analysis showed that the transcription cofactor vestigial-like 3 (VGLL3) gene expression was upregulated by mechanical tension in the mouse cranial suture, coinciding with accelerated osteoblast differentiation. Therefore, we hypothesized that VGLL3 plays a significant role in osteogenic differentiation. To clarify the function of VGLL3 in osteoblasts, we examined its expression characteristics in mouse bone tissue and the osteoblastic cell line MC3T3-E1. We further examined the effects of Vgll3 knockdown on osteoblast differentiation and bone morphogenetic protein (BMP) signaling. In the mouse cranial suture, where membranous ossification occurs, VGLL3 was immunohistochemically detected mostly in the nucleus of osteoblasts, preosteoblasts, and fibroblastic cells. VGLL3 expression in MC3T3-E1 cells was transient and peaked at a relatively early stage of differentiation. RNA sequencing revealed that downregulated genes in Vgll3-knockdown cells were enriched in gene ontology terms associated with osteoblast differentiation. Interestingly, most of the upregulated genes were related to cell division. Targeted Vgll3 knockdown markedly suppressed the expression of major osteogenic transcription factors (Runx2, Sp7/osterix, and Dlx5) and osteoblast differentiation. It also attenuated BMP signaling; moreover, exogenous BMP2 partially restore osteogenic transcription factors' expression in Vgll3-knockdown cells. Furthermore, overexpression of Vgll3 increased the expression of osteogenic transcription factors. These results suggest that VGLL3 plays a critical role in promoting osteoblast differentiation and that part of the process is mediated by BMP signaling. Further elucidation of VGLL3 function will increase our understanding of osteogenesis and skeletal disease etiology.

The effect and mechanism of gene Fam20a on the development and function of salivary glands in mice.

OBJECTIVE: The influence of the knockout of gene Fam20a on mice salivary glands was studied in this research, to provide a potential gene therapeutic target for salivary gland dysfunction. DESIGN: The control group with genotype Fam20af/f and conditional knockout (cKO) group with Fam20af/f;K14-Cre were constructed with Cre-Loxp. The influence of Fam20a on the salivary glands was studied in terms of morphology, functionality and molecular mechanism. RESULTS: In terms of morphology, the cross-sectional area ratio of ductal to the total was reduced in the cKO mice, while that of extracellular matrix to the total was increased. At the sub-microscopic level, the knockout of Fam20a led to abnormal sub-microscopic structure of the duct cells. Functionally, saliva flow rate was significantly reduced in cKO mice. The result was consistent with the change of acinar cell marker Aquaporin 5 which was abnormally diffusely expressed in the cytoplasm of acinar cells. Meanwhile, the expression of ductal cell markers Cytokeratin 7 and nerve growth factor ß were significantly decreased, suggesting the abnormal development and function of the duct cells. The research on the mechanism reveals that the loss of Fam20a led to the decreased expression and varied localization of bone morphogenetic protein 4 (BMP4), and a significant decrease of the proportion of phosphorylated extracellular signal-regulated protein1/2 (ERK1/2) to total ERK1/2. These changes suggested that the loss of Fam20a attenuated the activity of the BMP/ERK signaling pathway. CONCLUSIONS: Fam20a affects the morphology and function of salivary glands, probably by attenuating the activity of the BMP/ERK signaling pathway.

N-(3-oxododecanoyl)-homoserine lactone regulates osteoblast apoptosis and differentiation by mediating intracellular calcium.

Pseudomonas aeruginosa (P. aeruginosa) is associated with periapical periodontitis. The lesions are characterized by a disorder in osteoblast metabolism. Quorum sensing molecular N-(3-oxododecanoyl)-homoserine lactone (AHL) is secreted by P. aeruginosa and governs the expression of numerous virulence factors. AHL can trigger intracellular calcium ([Ca2+]i) fluctuations in many host cells. However, it is unclear whether AHL can regulate osteoblast metabolism by affecting [Ca2+]i changes or its spatial correlation. We explored AHL-induced apoptosis and differentiation in pre-osteoblastic MC3T3-E1 cells and evaluated [Ca2+]i mobilization using several extraction methods. The spatial distribution pattern of [Ca2+]i among cells was investigated by Moran's I, an index of spatial autocorrelation. We found that 30 µM and 50 µM AHL triggered opposing osteoblast fates. At 50 µM, AHL inhibited osteoblast differentiation by promoting mitochondrial-dependent apoptosis and negatively regulating osteogenic marker genes, including Runx2, Osterix, bone sialoprotein (Bsp), and osteocalcin (OCN). In contrast, prolonged treatment with 30 µM AHL promoted osteoblast differentiation concomitantly with cell apoptosis. The elevation of [Ca2+]i levels in osteoblasts treated with 50 µM AHL was spatially autocorrelated, while no such phenomenon was observed in 30 µM AHL-treated osteoblasts. The blocking of cell-to-cell spatial autocorrelation in the osteoblasts provoked by 50 µM AHL significantly inhibited apoptosis and partially restored differentiation. Our observations suggest that AHL affects the fate of osteoblasts (apoptosis and differentiation) by affecting the spatial correlation of [Ca2+]i changes. Thus, AHL acts as a double-edged sword for osteoblast function.

Inhibitory effect of retinoic acid receptor agonists on in vitro chondrogenic differentiation.

Retinoic acid (RA), an active metabolite of vitamin A, plays pivotal roles in a wide variety of biological processes, such as body patterning, organ development, and cell differentiation and proliferation. RA signaling is mediated by nuclear retinoic acid receptors, α, ß, and γ (RARα, RARß, and RARγ). RA is a well-known regulator of cartilage and skeleton formation and RARs are also essential for skeletal growth and hypertrophic chondrocyte-specific gene expression. These important roles of RA and RARs in chondrogenesis have been widely investigated using in vivo mouse models. However, few reports are available on the function of each subtype of RARs on in vitro chondrocyte differentiation. Here, we examined the effect of specific agonists of RARs on chondrogenic differentiation of ATDC5 and C3H10T1/2 cells. Subtype-specific RAR agonists as well as RA decreased the expressions of chondrogenic differentiation marker genes and inhibited chondrogenic differentiation, which was accompanied with morphological change to spindle-shaped cells. Among RAR agonists, RARα and RARγ agonists revealed a strong inhibitory effect on chondrogenic differentiation. RARα and RARγ agonists also hampered viability of ATDC5 cells. These observations suggested that RARα and RARγ are dominant receptors of RA signaling that negatively regulate chondrogenic differentiation.

Loss of Fam20c causes defects in the acinar and duct structure of salivary glands in mice.

Family with sequence similarity 20­member C (FAM20C), a recently characterized Golgi kinase, performs numerous biological functions by phosphorylating more than 100 secreted proteins. However, the role of FAM20C in the salivary glands remains undefined. The present study demonstrated that FAM20C is mainly located in the cytoplasm of duct epithelial cells in the salivary glands. Fam20cf/f; Mmtv­Cre mice were created in which Fam20c was inactivated in the salivary gland cells and observed that the number of ducts and the ductal cross­sectional area increased significantly, while the number of acinar cells was reduced. The granular convoluted tubules (GCTs) exhibited an accumulation of aberrant secretory granules, along with a reduced expression and altered distribution patterns of ß nerve growth factor, α­amylase and bone morphogenetic protein (BMP) 4. This abnormality suggested that the GCT cells were immature and exhibited defects in developmental and secretory functions. In accordance with the morphological alterations and the reduced number of acinar cells, FAM20C deficiency in the salivary glands significantly decreased the salivary flow rate. The Na+, Cl- and K+ concentrations in the saliva were all significantly increased due to dysfunction of the ducts. Furthermore, Fam20c deficiency significantly increased BMP2 and BMP7 expression, decreased BMP4 expression, and attenuated the canonical and noncanonical BMP signaling pathways in the salivary glands. Collectively, the results of the present study demonstrate that FAM20C is a key regulator of acinar and duct structure and duct maturation and provide a novel avenue for investigating novel therapeutic targets for oral diseases including xerostomia.