Silicosis, a progressive inflammatory lung disease attributed mainly to occupational exposure to silica dust, shows loss of lung function even after cessation of exposure. In addition to conventional ...evaluation methods such as chest X-ray, computed tomography, and spirometry, we identified heme oxygenase (HO)-1, an inducible antioxidant, as a potential biomarker to identify at-risk patients. We found that HO-1 was critical in attenuating the disease progression of silicosis; however, the key signaling pathway has not yet been elucidated. Here, we report the critical pathway after silica exposure, focusing on the role of silica-derived reactive oxygen species (ROS) signaling and its attenuation, which is mediated by HO-1 induction, in vivo and in vitro.
Normal bronchial epithelial cells and a macrophage cell line, as well as a murine silicosis model generated by intratracheal administration of 2.5 mg of crystalline silica, were used in this study. The pathways activated in response to silica exposure, including the mitogen-activated protein kinase (MAPK) signaling pathway, were examined and compared with or without super-induction of HO-1.
The murine silicosis model was first assessed for the evaluation of activated pathways after silica exposure, focusing on ROS-MAPK activation. In the murine model, increased expression of HO-1 in the lungs was observed after silica-instillation. Moreover, silica-medicated activation of extracellular signal-regulated kinase (ERK) in the lungs was attenuated in response to silica-induced HO-1 upregulation. Activation of other MAPKs, such as p38 and c-Jun N-terminal kinase pathways, after silica exposure was not significantly different irrespective of HO-1 induction. Further in vitro studies showed that 1) silica-induced HO-1 was significantly attenuated by inhibiting ERK activation, and 2) carbon monoxide and bilirubin as final byproducts of HO-1 could inhibit ERK activation. Taken together, silica-induced HO-1 upregulation was mediated by ERK activation, and HO-1 further regulates ERK activation via its final byproducts, carbon monoxide and bilirubin.
This is the first study to demonstrate the regulatory role of HO-1 in silicosis. This finding could contribute to the development of a treatment strategy of monitoring HO-1 levels as a marker of therapeutic intervention.
A computational knee model facilitates efficient component design evaluations and preclinical testing under various dynamic loadings. However, the development of a highly mimicked dynamic whole knee ...model with specified ligament constraints that provides high predictive accuracy with in-vivo experiments remains a challenge.
In the present study, a musculoskeletal integrated force-driven explicit finite-element knee model with tibiofemoral and patellofemoral joints constrained with detailed soft tissue was developed. A proportional-integral-derivative controller was concurrently added to the knee model to track the boundary conditions. The actuations of the quadriceps and hamstrings were predicted via a subject-specific musculoskeletal model and matched with electromyography results.
Compared to in-vivo fluoroscopic results in a gait cycle, the predicted results of the kinematics of the tibiofemoral joint exhibited an agreement in terms of tendency and magnitude (anterior–posterior translation: RMSE = 1.1 mm, r2 = 0.87; inferior–superior translation: RMSE = 0.83 mm, r2 = 0.84; medial–lateral translation: RMSE = 0.82 mm, r2 = 0.05; flexion–extension rotation: RMSE = 0.23°, r2 = 1; internal-external rotation: RMSE = 1.85°, r2 = 0.65; varus–valgus rotation: RMSE = 1.39°, r2 = 0.08). Contact mechanics, including the contact area, pressure, and stress, were synchronously simulated on the tibiofemoral and patellofemoral joints.
The study provides a calibrated knee model and a kinematical validation approach that can be widely used in preclinical testing and knee prosthesis design.
•A musculoskeletal integrated force-driven finite element knee model was developed and verified by experiments.•The predicted results of kinematics of the tibiofemoral joint exhibited an agreement with in-vivo fluoroscopic results.•Contact mechanics including the contact area, pressure, and stress can be synchronously simulated by the proposed knee model.
Physically unclonable functions (PUFs) are important primitives in the field of hardware security. Their applications can be further broadened if PUFs are fabricated using organic thin-film ...transistors (OTFTs). Examples include smart packaging that proves authenticity of a contained product and privacy protection for information gathered by organic sensors. This paper proposes an organic current mirror PUF (OCM-PUF) that can be fabricated on a flexible substrate. The proposed OCM-PUF adapts a current mirror structure to achieve self-compensation of the device performance degradation of OTFTs, which is unavoidable in most organic materials. Two types of OCM-PUFs were designed using a low supply voltage OTFT to evaluate the metrics as a PUF. The fabricated OCM-PUFs maintained a reliability of nearly 95% over few weeks, thereby showing that the proposed PUF achieved a high tolerance against response changes caused by device aging.
•A tandem mass spectrometer for photodissociation spectroscopy of temperature-controlled hydrogen-bonded cluster ions was developed.•Enantiomer-specific CαCβ bond cleavage exhibited a clear ...dependence on temperature.•Enantiomer-selective photolysis of cold amino acids on chiral substances in the gas phase could induce an excess of l-amino acids.
Enantiomer-selective ultraviolet photolysis of temperature-controlled protonated tryptophan (TrpH+) on the chiral crown ether, (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18C6TA), was examined using a tandem mass spectrometer containing a temperature-variable 22-pole ion trap. The spectra of d-TrpH+-(+)-18C6TA at 9–320K showed that the loss of NH2CH2COOH due to CαCβ bond cleavage decreased gradually with increasing temperature. The spectrum at room temperature was similar to that of l-TrpH+-(+)-18C6TA, which showed no temperature dependence on photolysis. The chiral-specific photolysis of cold d-TrpH+-(+)-18C6TA was attributed to the structures involving the chiral-dependent interactions of the CαH group of TrpH+ with the oxygen atoms of (+)-18C6TA.
Granulation tissue formation during skin wound healing requires the migration and proliferation of dermal fibroblasts in the wound site, where a subsequent remodeling of extracellular matrices (ECM) ...occurs. An abnormality of ECM remodeling within the healing wound leads to fibrosis and a contracted scar. To evaluate whether acteoside, a phenylethanoid glycoside isolated from the leaves of Rehmannia glutinosa LIBOSCH., exhibits wound-healing actions, we examined the effect of acteoside on the expression of matrix metalloproteinases (MMPs) in normal human dermal fibroblasts (NHDF). Acteoside dose- and time-dependently augmented the activation of the precursor of MMP-2 (proMMP-2/progelatinase A) in untreated- and interleukin-1β-treated NHDF, while the alteration of the MMP-2 gene expression was negligible. The acteoside-induced proMMP-2 activation was associated with the augmented membrane-type 1 MMP (MT1-MMP) expression in the NHDF. In addition, the proMMP-2 activation was enhanced by two aglycones in acteoside: caffeic acid and 3,4-dihydroxyphenylethanol, which consist of catechol. However, there was no change in the proMMP-2 activation in other catechol derivatives: homovanillyl alcohol- and homovanillic acid-treated NHDF, indicating that catechols in acteoside were requisite for the regulation of the MMP activation and expression in NHDF. Furthermore, the proMMP-2 activation by acteoside was selectively inhibited by LY294002, a potent phosphatidylinositol-3-kinase (PI3K) inhibitor. These results provide novel evidence that acteoside augments proMMP-2 activation along with an increase in MT1-MMP expression through a PI3K signal pathway in NHDF. Thus, acteoside is likely to be an attractive candidate that facilitates ECM remodeling in the skin wound repair process.
A number of proteins are known to be involved in apical/basolateral transport of proteins in polarized epithelial cells. The small GTP-binding protein Rab8 was thought to regulate basolateral ...transport in polarized kidney epithelial cells through the AP1B-complex-mediated pathway. However, the role of Rab8 (Rab8A) in cell polarity in vivo remains unknown. Here we show that Rab8 is responsible for the localization of apical proteins in intestinal epithelial cells. We found that apical peptidases and transporters localized to lysosomes in the small intestine of Rab8-deficient mice. Their mislocalization and degradation in lysosomes led to a marked reduction in the absorption rate of nutrients in the small intestine, and ultimately to death. Ultrastructurally, a shortening of apical microvilli, an increased number of enlarged lysosomes, and microvillus inclusions in the enterocytes were also observed. One microvillus inclusion disease patient who shows an identical phenotype to Rab8-deficient mice expresses a reduced amount of RAB8 (RAB8A; NM_005370). Our results demonstrate that Rab8 is necessary for the proper localization of apical proteins and the absorption and digestion of various nutrients in the small intestine.
A single-chain variable fragment (scFv) antibody is a recombinant protein in which a peptide linker connects the variable regions of the heavy chain and light chain. Due to its smaller molecular ...size, an scFv can be expressed using Escherichia coli. The presence of two disulphide bonds in the molecule often prevents expression of correctly folded scFv in the E. coli cytoplasm, making a refolding process necessary to regenerate scFv activity. The refolding process is time-consuming and requires large amounts of expensive reagents, such as guanidine hydrochloride, l-arginine and glutathione. Here, to conveniently obtain scFv proteins, we devised a simple and systematic method to optimize the co-expression of chaperone proteins and to combine them with specially engineered E. coli strains that permit the formation of stable disulphide bonds within the cytoplasm. Several scFv proteins were successfully obtained in a soluble form from E. coli cytoplasm. Thermal denaturation experiments and/or surface plasmon resonance measurements revealed that the thus-obtained scFvs possessed a stable tertiary structure and antigen-binding activity. The combined use of engineered E. coli with the simplified and systematic chaperone optimization can be useful for the production of scFv proteins.
Patients with non-small cell lung cancer (NSCLC) that harbors epidermal growth factor receptor (EGFR) mutations initially respond to EGFR-tyrosine kinase inhibitors (TKI) but eventually experience ...relapse. Acquired resistance to EGFR-TKIs is strongly associated with patient mortality. Thus, elucidation of the mechanism of acquired resistance to EGFR-TKIs is of great importance. In this study, gefitinib-resistant cell line models were established by long-term exposure to gefitinib using the gefitinib-sensitive lung cancer cell lines, PC9 and HCC827. Expression analyses indicated that both FGFR1 and FGF2 were increased in PC9 gefitinib-resistant (PC9 GR) cells as compared with PC9 naïve (PC9 na) cells. Importantly, proliferation of gefitinib-resistant cells was dependent on the FGF2 -FGFR1 pathway. Mechanistically, inhibition of either FGF2 or FGFR1 by siRNA or FGFR inhibitor (PD173074) restored gefitinib sensitivity in PC9 GR cells. These data suggest that FGF2 -FGFR1 activation through an autocrine loop is a novel mechanism of acquired resistance to EGFR-TKIs.
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