The Regulatory Role of PRRX1 in Cancer Epithelial-Mesenchymal Transition.

PRRX1 (paired related homeobox 1), a member of the paired homeobox family, exhibits an important role in tumor. It is closely correlated to the occurrence of epithelial-mesenchymal transition (EMT). PRRX1 is an important transcription factor regulating EMT and plays an important role in tumor progression. In the process of tumor metastasis, PRRX1 mainly regulates the occurrence of EMT in tumor cells through TGF-ß signaling pathway, Wnt/ß-catenin signaling pathway and Notch signaling pathway. PRRX1 is not only closely related to the tumor cell stemness but also involved in miRNA regulation of EMT. Therefore, PRRX1 may be a target for inhibiting the proliferation, metastasis and stemness of tumor cells. The current review provides a systemic profile of the regulatory role of PRRX1 in cancer epithelial-mesenchymal transition.

Source identification of PM2.5 at a port and an adjacent urban site in a coastal city of China: Impact of ship emissions and port activities.

Daily PM2.5 samples were collected simultaneously at an urban site (UB) and a nearby port-industrial site (PI) on the coast of southeastern China from April 2015 to January 2016. The PM2.5 mass concentration at the PI (51.9µgm-3) was significantly higher than that at the UB. The V concentration at the PI was also significantly higher and well-correlated to the urban value, which suggests that shipping emissions had a significant impact on the PI and, to a lesser extent, on the urban area. A positive matrix factorization (PMF) analysis showed that secondary aerosols were the dominant contribution of PM2.5 at both sites (36.4% at the PI and 27.2% at the UB), while the contribution of industry and ship emissions identified by V, Mn, and Ba at the PI (26.1%) were double those at the UB. The difference in each source contribution among the trajectory clusters that included significant differences and insignificant differences from the UB to the PI provided insight into the role of local impacts. With regards to the UB, local potential sources play important roles in industry and ship emissions, traffic emissions, fugitive dust, and in their contributions to secondary aerosols. A conditional probability function further revealed that the ship emissions and port activities distributed in the NE, E, and SSE wind sectors were responsible for the source contributions of industry and ship emissions and secondary aerosols at the UB. This study provides an example of investigating the impact of ship emissions and port activities on the surrounding air environment using land-based measurements.

Spatiotemporal distribution and source apportionment of low molecular weight organic acids in wet precipitation at a coastal city, China.

To investigate the characteristics and sources of low molecular weight (LMW) organic acids in wet precipitation at a coastal city, Xiamen, a total of 313 rainwater samples were collected at seven different functional areas from September 2012 to August 2013. Spatiotemporal characteristics of LMW organic acids as well as pH and electrical conductivity were analyzed. Meanwhile, air mass clusters in different seasons and the positive matrix factorization (PMF) source apportion model were comprehensively used to identify the sources of organic acids. In conclusion, the volume-weighted mean (VWM) concentration of formic (3.20 µmol/L), acetic (1.84 µmol/L), lactic (0.44 µmol/L), and oxalic acid (0.53 µmol/L) were obtained, which jointly contributed to 4.33% of the total free acidity (TFA). At the same time, the highest wet deposition flux of LMW organic acids and contribution of that to TFA were achieved at the forest protection area during growing season in Xiamen. In addition, biogenic emissions (77.12%), sea salts (13.77%), regional agriculture activities (3.92%), soil emissions (2.56%), biomass burning (1.47%), and secondary aerosols (1.15%) were determined as the source of LMW organic acids. Besides, the dominancy of biomass burning via long-range transport in non-growing season (NGS) and the contribution of biogenic emission in growing season (GS) were recognized. Finally, the considerable influence of sea salts on the LMW organic acids (13.77%) in Xiamen was quantified, especially for oxalic acid.

Chemical composition, structural properties, and source apportionment of organic macromolecules in atmospheric PM10 in a coastal city of Southeast China.

Particulate matter (PM10) associated with the fractions of organic macromolecules, including humic acid (HA), kerogen + black carbon (KB), and black carbon (BC), was determined during summer and winter at urban and suburban sites in a coastal city of southeast China. The organic macromolecules were characterized by elemental analysis (EA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR), and their sources were identified by using stable carbon/nitrogen isotope (δ13C/δ15N) and the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model. The results showed that HA, kerogen (K), and BC accounted for the range of 3.89 to 4.55 % in PM10, while they were the dominant fractions of total organic carbon (TOC), ranging from 64.70 to 84.99 %. SEM analysis indicated that BC particles were porous/nonporous and consisted of spherical and non-spherical (i.e., cylindrical and elongate) structures. The FTIR spectra of HA, KB, and BC exhibited similar functional groups, but the difference of various sites and seasons was observed. HA in PM10 contained a higher fraction of aliphatic structures, such as long-chain fatty and carbohydrates with a carboxylic extremity. The C/N ratio, SEM, and δ13C/δ15N values provided reliable indicators of the sources of HA, K, and BC in PM10. The results suggested that HA and K majorly originated from terrestrial plants, and BC came from the mixture of combustion of terrestrial plants, fossil fuel, and charcoal. The air masses in winter originated from Mongolia (4 %), the northern area of China (48 %), and northern adjacent cities (48 %), suggesting the influence of anthropogenic sources through long-range transport, while the air masses for the summer period came from South China Sea (34 %) and Western Pacific Sea (66 %), representing clean marine air masses with low concentrations of organic macromolecules.

[Pollution Characteristics of Heavy Metals in PM2.5 and Their Human Health Risks Among the Coastal City Group Along Western Taiwan Straits Region, China].

PM2.5 samples were collected from 11 sampling sites in the coastal city group along western Taiwan Straits region, China, and these heavy metal elements (Zn, Cu, Pb, Ni, Cr, As) were detected using particle-induced X-ray emission (PIXE) method. The pollution characteristics, enrichment factors and source apportionment of heavy metals in PM2.5 were analyzed, and furthermore, their human health risks were determined. The result showed concentration distribution was obviously different between PM2.5 and heavy metals in the city group, for the main sources (e.g. construction dust and ground dust) for PM2.5 were not the main contribution to these heavy metals. The enrichment factors of Zn, Cu, Pb, Mn, Ni, Cr, As exceeded 10, which suggested these metals were enriched and significantly impacted by anthropogenic pollution. Three main groups of heavy metals in PM2.5 were identified by principal component analysis (PCA-MLR), such as coal combustion and traffic emissions (70.59%), multiple sources (coal and oil combustion, pyrometallurgical process, 17.55%) and other industry (11.86%). The risk levels for carcinogenic heavy metals (Ni, Cr, As) and non-carcinogenic heavy metals (Zn, Cu, Pb, Mn) were lower than the average level of risk acceptance (10-6), which suggested these heavy metals did not cause harm to human health in these cities.

Optical properties of PM2.5 and the impacts of chemical compositions in the coastal city Xiamen in China.

Continuous in situ measurements of optical properties of fine aerosols (PM2.5) were conducted in the urbanized coastal city Xiamen in Southeast China from November 2013 to January 2014. PM2.5 samples were also collected and chemical compositions including organic carbon (OC), elemental carbon (EC) and water-soluble inorganic ions were determined to investigate the impacts of chemical compositions on aerosol optical properties. Average values of scattering coefficient (bscat), absorption coefficient (babs), extinction coefficient (bext) and single scattering albedo (SSA) were 164.0Mm(-1), 22.4Mm(-1), 187.0Mm(-1) and 0.88, respectively. bscat, babs and bext showed obvious bi-modal diurnal variations with high values in the morning and at night while low value in the early afternoon, whereas SSA exhibited an opposite diurnal variation. Average bscat and babs were largest in the wind direction of southwest and were larger with slower wind. babs was mainly affected by EC, while bscat was affected by ammonium, sulfate, nitrate and OC. The IMPROVE formula was applied to estimate bext based on the chemical species. Results shows that ammonium sulfate was the largest contributor, accounting for 36.4% of bext, followed by organic matter (30.6%), ammonium nitrate (20.1%), EC (9.0%) and sea salt (3.9%). The deterioration in visibility was mainly led by increases in secondary aerosols including sulfate and nitrate. Backward trajectories analysis showed that during the sampling period Xiamen was significantly affected by the air masses originating from the Northern and Northeastern areas. Air masses from the Northern associated with relative higher bext and less relative contribution from ammonium sulfate and more relative contribution from ammonium nitrate, organic matter and sea salt.

Increase in hypotonic stress-induced endocytic activity in macrophages via ClC-3.

Extracellular hypotonic stress can affect cellular function. Whether and how hypotonicity affects immune cell function remains to be elucidated. Macrophages are immune cells that play key roles in adaptive and innate in immune reactions. The purpose of this study was to investigate the role and underlying mechanism of hypotonic stress in the function of bone marrow-derived macrophages (BMDMs). Hypotonic stress increased endocytic activity in BMDMs, but there was no significant change in the expression of CD80, CD86, and MHC class II molecules, nor in the secretion of TNF-α or IL-10 by BMDMs. Furthermore, the enhanced endocytic activity of BMDMs triggered by hypotonic stress was significantly inhibited by chloride channel-3 (ClC-3) siRNA. Our findings suggest that hypotonic stress can induce endocytosis in BMDMs and that ClC-3 plays a central role in the endocytic process.

Extracellular acidosis modulates the endocytosis and maturation of macrophages.

Extracellular acidosis is involved in various pathological situations of central nervous system and the effects are largely mediated by acid sensing ion channels (ASICs). However, it remains unclear whether extracellular acidosis affects immune cells. Macrophages are immune cells that play important role in immune reactions. In this study we investigated the impact of extracellular acidosis on the function of bone marrow derived macrophages (BMMs). The results showed that extracellular acidosis upregulated the endocytosis, surface molecular expression and interleukin-10 secretion of BMMs, in which the expression of ASIC1 and ASIC3 was detected. Notably, extracellular acidosis stimulated endocytosis and upregulation of surface molecules expression in BMMs could be abolished by amiloride, a blocker of ASICs, and nonsteroid anti-inflammatory drugs. Our findings provide new insight into the role of extracellular acidosis in the regulation of immune function and suggest ASICs as new targets for the modulation of immune response.

Acid-sensing ion channels contribute to the effect of acidosis on the function of dendritic cells.

As an H(+)-gated subgroup of the degenerin/epithelial Na(+) channel family, acid-sensing ion channels (ASICs) were reported to be involved in various physiological and pathological processes in neurons. However, little is known about the role of ASICs in the function of dendritic cells (DCs). In this study, we investigated the expression of ASICs in mouse bone marrow-derived DCs and their possible role in the function of DCs. We found that ASIC1, ASIC2, and ASIC3 are expressed in DCs at the mRNA and protein levels, and extracellular acid can evoke ASIC-like currents in DCs. We also demonstrated that acidosis upregulated the expression of CD11c, MHC class II, CD80, and CD86 and enhanced the Ag-presenting ability of DCs via ASICs. Moreover, the effect of acidosis on DCs can be abolished by the nonsteroidal anti-inflammatory drugs ibuprofen and diclofenac. These results suggest that ASICs are involved in the acidosis-mediated effect on DC function.