14-3-3ζ inhibits maladaptive repair in renal tubules by regulating YAP and reduces renal interstitial fibrosis.

Acute kidney injury (AKI) refers to a group of common clinical syndromes characterized by acute renal dysfunction, which may lead to chronic kidney disease (CKD), and this process is called the AKI-CKD transition. The transcriptional coactivator YAP can promote the AKI-CKD transition by regulating the expression of profibrotic factors, and 14-3-3 protein zeta (14-3-3ζ), an important regulatory protein of YAP, may prevent the AKI-CKD transition. We established an AKI-CKD model in mice by unilateral renal ischemia-reperfusion injury and overexpressed 14-3-3ζ in mice using a fluid dynamics-based gene transfection technique. We also overexpressed and knocked down 14-3-3ζ in vitro. In AKI-CKD model mice, 14-3-3ζ expression was significantly increased at the AKI stage. During the development of chronic disease, the expression of 14-3-3ζ tended to decrease, whereas active YAP was consistently overexpressed. In vitro, we found that 14-3-3ζ can combine with YAP, promote the phosphorylation of YAP, inhibit YAP nuclear translocation, and reduce the expression of fibrosis-related proteins. In an in vivo intervention experiment, we found that the overexpression of 14-3-3ζ slowed the process of renal fibrosis in a mouse model of AKI-CKD. These findings suggest that 14-3-3ζ can affect the expression of fibrosis-related proteins by regulating YAP, inhibit the maladaptive repair of renal tubular epithelial cells, and prevent the AKI-CKD transition.

The changes in glucose metabolism and cell proliferation in the kidneys of polycystic kidney disease mini-pig models.

The pathogenic mechanism of polycystic kidney disease (PKD) is unclear. Abnormal glucose metabolism is maybe involved in hyper-proliferation of renal cyst epithelial cells. Mini-pigs are more similar to humans than rodents and therefore, are an ideal large animal model. In this study, for the first time, we systematically investigated the changes in glucose metabolism and cell proliferation signaling pathways in the kidney tissues of chronic progressive PKD mini-pig models created by knock-outing PKD1gene. The results showed that in the kidneys of PKD mini-pigs, the glycolysis is increased and the expressions of key oxidative phosphorylation enzymes Complexes I and IV significantly decreased. The activities of mitochondrial respiration chain Complexes I and IV significantly decreased; the phosphorylation level of key metabolism-modulating molecule AMP-activated protein kinase (AMPK) significantly decreased; and the mammalian target of rapamycin (mTOR) and extracellular signal-regulated kinase (ERK) signaling pathway are activated obviously. This study showed that in the kidneys of PKD mini-pigs, the level of glycolysis significantly increased, oxidative phosphorylation significantly decreased, and cell proliferation signaling pathways significantly activated, suggesting that metabolic changes in PKD may result in the occurrence and development of PKD through the activation of proliferation signaling pathways.

Anti-Inflamm-Aging Effects of Long-Term Caloric Restriction via Overexpression of SIGIRR to Inhibit NF-κB Signaling Pathway.

BACKGROUND: Chronic inflammation is thought to be a determinant of the aging rate and longevity. Caloric restriction (CR) attenuates age-related increases in the systemic levels of several pro-inflammatory mediators, but the anti-inflammatory mechanisms of CR in the aging process remain unclear. METHODS: Fisher 344 rats in a CR group were fed an amount of food corresponding to 60% of that fed to an ad libitum-fed (AL) group for 8 months. Biochemical analyses and renal pathological grading were used to analyze physiological status. Important signaling molecules in the Toll-like receptor/nuclear factor kappa-light-chain-enhancer of activated B cells (TLR/NF-κB) pathway were also analyzed by western blotting, immunofluorescence and immunohistochemistry. RESULTS: 1) Compared with AL feeding, CR decreased aging-mediated increases in both biochemical marker levels and renal pathological grading. 2) Single immunoglobulin IL-1 (IL-1)-related receptor (SIGIRR) expression decreased with increasing age, but CR led to overexpression. 3) The expression of TLR4 was significantly higher in the CR group than in the AL group. 4) SIGIRR overexpression decreased the expression of the adaptor molecules myeloid differentiation factor 88 (MyD88), IL-1 receptor-associated kinase 4 (IRAK4) and tumor necrosis factor receptor-associated factor 6 (TRAF6). 5) The levels of the inflammatory markers phospho-IκBα and phospho-NF-κB p65 decreased in the CR group. CONCLUSIONS: The inflammatory response might be alleviated by SIGIRR via blockade of the TLR4/NF-κB signaling pathway. Therefore, CR can decrease inflammation via SIGIRR overexpression, and SIGIRR might be a new target to delay aging.

miR-34a regulates mesangial cell proliferation via the PDGFR-ß/Ras-MAPK signaling pathway.

The main pathological characteristic of glomerulonephritis is diffuse mesangial cell proliferation. MiR-34a is associated with the proliferation of various organs and cancer cells. However, the role of miR-34a in renal proliferation diseases is not clear. Therefore, this study aimed to elucidate the mechanism of miR-34a in the regulation of renal mesangial cell proliferation. The miR-34a expression level at different time points in an anti-Thy1 mesangial proliferative nephritis rat model was determined by qRT-PCR. The cell proliferation rate and cell cycle changes were measured in the in vitro cultured rat mesangial cells (RMCs). Our results suggested that miR-34a expression was negatively correlated with the degree of cell proliferation in the anti-Thy1 nephritis model. MiR-34a could extend the G0/G1 phase and block cell proliferation in RMCs. Dual-luciferase assay results showed that there were binding sites of miR-34a at 3'-UTR of platelet-derived growth factor receptor-ß (PDGFR-ß). MiR-34a can inhibit PDGFR-ß protein expression at a post-transcriptional level, suppress Ras/MAPK signaling pathways, and down-regulate expression of cell cycle proteins at the G0/G1 phase, such as cyclin D1, CDK4/CDK6. In addition, miR-34a may also inhibit RMC proliferation by directly targeting cyclin E and CDK2. MiR-34a inhibits exogenous stimuli-induced proliferation of mesangial cells. Expression levels of phospho-PDGFR-ß and phospho-MEK1 (an important downstream molecule in PDGFR-ß-induced signaling pathway) were significantly increased in the anti-Thy-1 nephritis rat model. These results suggest that miR-34a may regulate RMC proliferation by directly inhibiting expressions of PDGFR-ß, MEK1, and cell cycle proteins, cyclin E and CDK2.

Single-Cell Sequencing Informs That Mesenchymal Stem Cell Alleviates Renal Injury Through Regulating Kidney Regional Immunity in Lupus Nephritis.

Lupus nephritis (LN) is the common complication of systemic lupus erythematosus. The pathogenesis of LN kidney injury is unclear. In addition to systemic (extrarenal) immune cells, local (intrarenal) immune cells residing in "kidney regional immunity" are momentous in LN. Mesenchymal stem cell (MSC) therapy is effective for LN. However, mechanisms of MSC therapy remains unclear. In this study, we first systematically investigated the effects of MSC on immune cells in kidney regional immunity in LN using single-cell sequencing. We found that MSC reduced proinflammatory central memory CD4+ T cells, cytotoxic tissue-resident memory CD8+ T cells and exhausted CD8+ T cells, increased anti-inflammatory Naive/Effector CD8+ T cells and type 1 regulatory T cells; reduced infiltrating proinflammatory Ly6c hi/inter/lo era2+ macrophages, increased anti-inflammatory resident macrophage and Ly6c lo ear2- macrophage; and reduced long-lived plasma cells and proinflammatory neutrophils and dendritic cells. This study laid a foundation for clinical applications of MSC.

miR-335 and miR-34a Promote renal senescence by suppressing mitochondrial antioxidative enzymes.

The molecular basis for aging of the kidney is not well understood. MicroRNAs (miRNAs) contribute to processes such as development, differentiation, and apoptosis, but their contribution to the aging process is unknown. Here, we analyzed the miRNA expression profile of young (3-month) and old (24-month) rat kidneys and identified the biologic pathways and genes regulated by differentially expressed miRNAs. We observed upregulation of 18 miRNAs with aging, mainly regulating the genes associated with energy metabolism, cell proliferation, antioxidative defense, and extracellular matrix degradation; in contrast, we observed downregulation of 7 miRNAs with aging, principally targeting the genes associated with the immune inflammatory response and cell-cycle arrest. Bioinformatics analysis suggested that superoxide dismutase 2 (SOD2) and thioredoxin reductase 2 (Txnrd2), located in the mitochondria, are potential targets of miR-335 and miR-34a, respectively. Aging mesangial cells exhibited significant upregulation of miR-335 and miR-34a and marked downregulation of SOD2 and Txnrd2. miR-335 and miR-34a inhibited expression of SOD2 and Txnrd2 by binding to the 3'-untranslated regions of each gene, respectively. Overexpression of miR-335 and miR-34a induced premature senescence of young mesangial cells via suppression of SOD2 and Txnrd2 with a concomitant increase in reactive oxygen species (ROS). Conversely, antisense miR-335 and miR-34a inhibited senescence of old mesangial cells via upregulation of SOD2 and Txnrd2 with a concomitant decrease in ROS. In conclusion, these results suggest that miRNAs may contribute to renal aging by inhibiting intracellular pathways such as those involving the mitochondrial antioxidative enzymes SOD2 and Txnrd2.

Strategies for the induction of anti-inflammatory mesenchymal stem cells and their application in the treatment of immune-related nephropathy.

Mesenchymal stem cells (MSCs) have potent immunomodulatory functions. Animal studies and clinical trials have demonstrated that MSCs can inhibit immune/inflammatory response in tissues and have good therapeutic effects on a variety of immune-related diseases. However, MSCs currently used for treatment are a mixed, undefined, and heterogeneous cell population, resulting in inconsistent clinical treatment effects. MSCs have dual pro-inflammatory/anti-inflammatory regulatory functions in different environments. In different microenvironments, the immunomodulatory function of MSCs has plasticity; therefore, MSCs can transform into pro-inflammatory MSC1 or anti-inflammatory MSC2 phenotypes. There is an urgent need to elucidate the molecular mechanism that induces the phenotypic transition of MSCs to pro-inflammatory or anti-inflammatory MSCs and to develop technical strategies that can induce the transformation of MSCs to the anti-inflammatory MSC2 phenotype to provide a theoretical basis for the future clinical use of MSCs in the treatment of immune-related nephropathy. In this paper, we summarize the relevant strategies and mechanisms for inducing the transformation of MSCs into the anti-inflammatory MSC2 phenotype and enhancing the immunosuppressive function of MSCs.

Establishment of PLAFMCi007-A, an induced pluripotent stem cell line, from peripheral blood mononuclear cells (PBMCs) of a healthy adult woman.

Induced pluripotent stem cell (iPSC) lines for studies investigating many diseases can be established from peripheral blood mononuclear cells; here, an iPSC line was established from CD34+ cells isolated from the peripheral blood of a healthy woman. The cells were electrotransfected with three different recombinant plasmids to generate a normal-karyotype iPSC line that expresses characteristic surface markers and other pluripotent stem cell genes and can differentiate into all three germ layers in vivo. These newly established iPSC lines, a normal human cell line, can serve as a control line in studies investigating the pathogenesis of various diseases and meet the conditions for organoid studies.

Establishment of the induced pluripotent stem cell line PLAFMCi006-A from peripheral blood mononuclear cells of polycystic kidney disease patients with PKD2 gene mutation.

Polycystic kidney disease (PKD) caused by PKD2 mutation is an important type of autosomal dominant PKD. In this study, peripheral blood mononuclear cells from a patient with PKD2 polycystic kidney disease were reprogrammed to obtain induced pluripotent stem cells (iPSCs). After stable amplification, the pluripotency of the iPSCs was determined by identifying their cell-surface markers, their expression of pluripotency-related genes, and their ability to form teratomas with three germ layers in vivo. The establishment of the iPSC line could provide a basis for a kidney-like organ model of human PKD caused by PKD2 mutation for use in studying the pathogenesis of PKD along with relevant screening and testing intervention drugs.

Effects of NaCl-assisted regulation on the emulsifying properties of heat-induced type I collagen.

Although collagen is widely used as an emulsifier in the food industry, its emulsifying properties are strongly influenced by processing conditions. This research investigated the effects of NaCl on the emulsifying properties of type I collagen after heating. Before heating, the solubility, emulsifying activity index (EAI), emulsifying stability index (ESI), and viscosity of type I collagen initially increased after adding NaCl (0.2 M), after which decreased with increasing NaCl concentration (0.4 M and 0.6 M) due to salt-in effect and the salt-out effects of the protein. While after heating (90℃, 30 min), the collagen became more soluble, with improved EAI and ESI, viscosity, and reduced particle size in response to increasing NaCl concentrations. It was found that NaCl increased the EAI of type I collagen twice after heating, and the EAI reached its maximum at 0.6 M NaCl concentration. We concluded that the improved emulsifying properties may due to thermal denaturation of the protein, resulting in an unfolded and disordered structure with increase of hydrogen bonds with water, rupture of disulfide bonds, and exposure of hydrophobic groups, leading to the increase of adsorption at the oil/water interface. Meanwhile, the Raman spectra analysis and Atomic Force Microscope (AFM) images showed that unfolding of the collagen triple helix was gradually destroyed after NaCl addition and heating, with emulsifying properties improved. The specific outcomes of present study can be adapted towards the requirements to improve the quality of emulsified meat products in the food industry.

Transient upregulation of EGR1 signaling enhances kidney repair by activating SOX9+ renal tubular cells.

Background: Acute kidney injury (AKI) is associated with damage to the nephrons and tubular epithelial cells (TECs), which can lead to chronic kidney disease and end-stage renal disease. Identifying new biomarkers before kidney dysfunction will offer crucial insight into preventive and therapeutic options for the treatment of AKI. Early growth response 1 (EGR1) has been found to be a pioneer transcription factor that can sequentially turn on/off key downstream genes to regulate whole-body regeneration processes in the leopard worm. Whether EGR1 modulates renal regeneration processes in AKI remains to be elucidated. Methods: AKI models of ischemia-reperfusion injury (IRI) and folic acid (FA) were developed to investigate the roles of EGR1 in kidney injury and regeneration. To further determine the function of EGR1, Egr1-/- mice were applied. Furthermore, RNA sequencing of renal TECs, Chromatin Immunoprecipitation (ChIP) assay, and Dual-luciferase reporter assay were carried out to investigate whether EGR1 affects the expression of SOX9. Results: EGR1 is highly expressed in the kidney after AKI both in humans and mice through analysis of the Gene Expression Omnibus (GEO) database. Furthermore, we verified that EGR1 rapidly up-regulates in the very early stage of IRI and nephrotoxic models of AKI, and validation studies confirmed the essential roles of EGR1 in renal tubular cell regeneration. Further experiments affirmed that genetic inhibition of Egr1 aggravates the severity of AKI in mouse models. Furthermore, our results revealed that EGR1 could increase SOX9 expression in renal TECs by directly binding to the promoter of the Sox9 gene, thus promoting SOX9+ cell proliferation by activating the Wnt/ß-catenin pathway. Conclusions: Together, our results demonstrated that rapid and transient induction of EGR1 plays a renoprotective role in AKI, which highlights the prospects of using EGR1 as a potential therapeutic target for the treatment of AKI.

[Effects of deer tendons collagen on osteoporosis rats induced by retinoic acid].

OBJECTIVE: To study the effects of deer tendons collagen on osteoporosis rats induced by retinoic acid. METHODS: Male Wistar rats were randomly divided into normal control group, model control group, deer tendons collagen high, medium and low-dose groups, osteoporosis rats of retinoic acid-induced were set up. Changes of body weight, bone weight, bone mineral density, bone histomorphometry, plasma phosphorus, calcium, alkaline phosphatase (ALP), bone mechanics were measured before and after treatment of deer tendons collagen. RESULTS: Compared with model control group,after treated by deer tendons collagen, body weight, bone mineral density, bone weight was increased in varying degrees, bone histomorphometry parameters were significantly different, the ALP in plasma was significantly reduced, contents of Ca, P were increased, all indicators of bone mechanics were significantly higher. CONCLUSION: Deer tendons collagen can prevent and treat retinoic acid-induced osteoporosis of rats.

N-Acetylcysteine Ameliorates Gentamicin-Induced Nephrotoxicity by Enhancing Autophagy and Reducing Oxidative Damage in Miniature Pigs.

The clinical use of gentamicin over prolonged periods is limited because of dose and time-dependent nephrotoxicity, in which intracellular oxidative stress and heightened inflammation have been implicated. Macroautophagy/autophagy is an essential and highly conserved self-digestion pathway that plays important roles in the maintenance of cellular function and viability under stress. The aim of this study was to determine changes in autophagy in response to the antioxidant N-acetylcysteine (NAC), via its effects on oxidative stress, inflammation, apoptosis, and renal function, following treatment with gentamicin in mini pigs. Adult mini pigs were divided into isotonic saline solution, gentamicin, and gentamicin plus NAC combination treatment groups. Gentamicin-induced histopathological changes, including inflammatory cell infiltration and tubular necrosis, were attenuated by NAC. NAC ameliorated the gentamicin-induced decreases in the levels of autophagy-related proteins, such as LC3 (microtubule-associated protein 1 light chain 3), PINK1 (phosphatase and tensin homologue deleted on chromosome10-induced kinase 1), phospho-parkin, AMBRA1 (activatingmolecule in Beclin 1-regulated autophagy), p62/SQSTM1 (sequestosome protein 1), and polyubiquitinated protein aggregates. NAC also caused a significant reduction in oxidative damage markers, including 4-hydroxy-2-nonenal, protein carbonyls, γ-H2AX (gamma histone variant H2AX), and 8-hydroxy-2'-deoxyguanosine, in gentamicin-treated animals. These data show that the protective effects of NAC might be related, at least in part, to a reduced inflammatory response, as observed in animals treated with both gentamicin and NAC. These results suggest that autophagy could be a new therapeutic target for preventing gentamicin-induced kidney injury, and that NAC might ameliorate gentamicin-induced nephrotoxicity by autophagy.

A pilot study of metabolites of organophosphorus flame retardants in paired maternal urine and amniotic fluid samples: potential exposure risks of tributyl phosphate to pregnant women.

Organophosphorus flame retardants (OPs) are of wide concern due to their presence in human urine and their considerable endocrine disruption and neuro-development toxicity. It has been confirmed that electronic waste (e-waste) dismantling activities have contributed to human exposure to OPs. However, assessments of OP exposure and the health risks for pregnant women and fetuses living in areas associated with e-waste dismantling have been impeded by a lack of data. In this study, six OP metabolites (mOPs) were measured in paired maternal urine and amniotic fluid samples collected from an e-waste dismantling area in Guangdong Province, China. All mOPs were detectable in maternal urine, whereas two were found in amniotic fluid. Dibutyl phosphate (DBP) was the predominant mOP in both maternal urine (geometric mean (GM): 2.9 ng ml-1) and amniotic fluid (1.3 ng ml-1); and diphenyl phosphate (DPHP) was the secondary one found (0.94 ng ml-1 in maternal urine, 0.12 ng ml-1 in amniotic fluid). The GM urinary concentrations of DBP and DPHP were two and seven times higher than those in amniotic fluid, respectively. The estimated daily intakes (EDIs) of triphenyl phosphate (TPHP) and tributyl phosphate (TnBP) by pregnant women were calculated from their daily urine excretion rate as fractions of OP metabolized to the corresponding metabolite (FUE). Our results showed high exposure levels to TPHP (median: 273 or 613 ng per kg bw per day) and TnBP (404 ng per kg bw per day) for pregnant women living in the e-waste associated area. Most importantly, 13% of mothers had EDITnBP levels that exceeded the reference dose (RfD: 2400 ng per kg bw per day), suggesting potential health risks from TnBP exposure for pregnant women living in areas associated with e-waste dismantling. This study, as a pilot study, presents the first measurements of mOPs in human amniotic fluid.

Low-dose 2-deoxyglucose and metformin synergically inhibit proliferation of human polycystic kidney cells by modulating glucose metabolism.

Polycystic kidney disease (PKD) is a common hereditary kidney disease with abnormal proliferation and apoptosis of kidney cystic epithelial cells, eventually leading to chronic renal failure. Currently, there are no effective treatment methods. Similar to tumor cells, cystic epithelial cells have abnormal glycolysis and over-activation of proliferation signaling pathways. In the present study, for the first time, we investigated the effects of low-dose combinational use of 2-deoxyglucose (2-DG) and metformin (MET) on the proliferation and apoptosis in the human cystic kidney epithelial cells. Cystic epithelia cells were divided into control group, 2-DG group, MET group and 2-DG+MET group. Cell Proliferation, apoptosis and glucose metabolism were measured in each group. The results showed that low-dose combinational treatment of 2-DG and MET significantly inhibited the proliferation of renal cystic epithelial cells by suppressing the activities of PKA, mTOR and ERK signaling pathways and upregulating PI3K/Akt pathway. Combination of both drugs increased the apoptosis rates of cystic epithelial cells. Two drugs inhibited glucose metabolic phenotypes, glycolysis and oxidative phosphorylation, and significantly lowered the intracellular ATP level in cystic epithelial cells. 2-DG could also neutralize excessive production of lactate (lactic acidosis) caused by MET and both drugs had complementary effect for cystic epithelial cells. These results reveal that combinational use of low-dose 2-DG and MET can markedly inhibit proliferation via modulating glucose metabolic phenotypes in human polycystic kidney epithelial cells, low-dose combinational use of both drugs can also lower the toxic effects of each drug, and is a novel strategy for future treatment of human polycystic kidney disease.

The combination of metformin and 2-deoxyglucose significantly inhibits cyst formation in miniature pigs with polycystic kidney disease.

BACKGROUND AND PURPOSE: The pathogenic mechanism of autosomal dominant polycystic kidney disease (ADPKD) is unclear. Similar to tumour cells, polycystic kidney cells are primarily dependent on aerobic glycolysis for ATP production. Compared with rodents, miniature pigs are more similar to humans. This study is the first time to investigate the effects of the combination of metformin and 2-deoxyglucose (2DG) in a pig model of chronic progressive ADPKD. EXPERIMENTAL APPROACH: A miniature pig ADPKD model was established by inducible deletion of the PKD1 gene. Blood, urine and kidney biopsy specimens were collected for analysis at specific times. The renal vesicle index was analysed by three-dimensional reconstruction of CT scans. Markers of the mammalian target of rapamycin (mTOR) and ERK signalling pathways and associated metabolism were detected by Western blots and colorimetry. KEY RESULTS: The three-dimensional reconstruction of CT scans indicated a markedly lower renal vesicle index in the combination therapy group. Each drug intervention group showed a significantly lower serum creatinine and urinary protein/creatinine ratio. This treatment regimen also inhibited the activities of markers of the proliferation-related mTOR and ERK pathways, and the expression of key enzymes involved in glycolysis, as well as reducing the production of ATP and lactic acid. CONCLUSIONS AND IMPLICATIONS: This study showed that the combination of metformin and 2DG blocked the formation of renal cysts and improved the renal function in ADPKD miniature pigs. Our results indicate that the combination of metformin and 2DG may be a promising therapeutic strategy in human ADPKD.

Membrane topology structure of human high-affinity, sodium-dependent dicarboxylate transporter.

High-affinity, sodium-dependent dicarboxylate transporter (NaDC3) is responsible for transport of Krebs cycle intermediates and may involve in regulation of aging and life span. Hydropathy analysis predicts that NaDC3 contains 11 or 12 hydrophobic transmembrane (TM) domains. However, the actual membrane topological structure of NaDC3 remains unknown. In this study, confocal immunofluorescence microscopy and membrane biotinylation of epitope-tagged N and C termini of NaDC3 provide evidence of an extracellular C terminus and an intracellular N terminus, indicating an odd number of transmembrane regions. The position of hydrophilic loops within NaDC3 was identified with antibodies against the loops domains combined with cysteine accessibility methods. A confocal image of membrane localization and transport activity assay of the cysteine insertion mutants show behavior similar to that of wild-type NaDC3 in transfected HEK293 cells, suggesting that these mutants retain a native protein configuration. We find that NaDC3 contains 11 transmembrane helices. The loops 1, 3, 5, 7, and 9 face the extracellular side, and loops 2, 4, 6, and 10 face the cytoplasmic side. A re-entrant loop-like structure between TM8 and TM9 may protrude into the membrane. Our results support the topography of 11 transmembrane domains with an extracellular C terminus and an intracellular N terminus of NaDC3, and for the first time provide experimental evidence for a novel topological model for NaDC3.

Urinary benzophenone-type UV filters in people living in South China: rural versus urban areas.

Benzophenone (BP)-type UV filters are widely used in sunscreen products to protect human skin from UV radiation. However, only a few studies have been conducted to determine the level of human exposure to BPs in rural areas of China. In this study, we evaluated the exposure levels of people living in three villages and a city in South China to five major BPs (BP-1, BP-2, BP-3, BP-8, and 4-OH-BP). The detection rates of BP-1, BP-3, and 4-OH-BP were 66%, 72%, and 75%, respectively, in rural areas and 85%, 75%, and 80%, correspondingly, in urban areas. BP-2 and BP-8 were rarely detected. The results indicated that people living in South China are extensively exposed to BPs, regardless of sampling sites (rural and urban areas). The observed concentrations of BP-1 (urban vs. rural = 1.04 ng mL-1vs. 0.21 ng mL-1) and BP-3 (0.37 ng mL-1vs. 0.16 ng mL-1) were significantly (one-way ANOVA, p < 0.01) lower in the rural areas than in the urban areas. BP-1 (59%) based on composition profile analysis was the dominant BP derivative in urine samples of urban residents, whereas 4-OH-BP (36%) was the most prevalent BP in rural areas. In the rural areas, significant positive correlations between urinary BP-1 and BP-3 (r = 0.529, p < 0.01) and between urinary BP-1 and 4-OH-BP (r = 0.323, p < 0.05) concentrations were obtained; in the urban areas, we only observed a clear correlation (p < 0.01) between BP-1 and 4-OH-BP. The different composition profiles and associations among urinary BPs indicated that exposure sources of BPs might be different between rural and urban areas. The distribution profiles of BP-1 and its parent compound (i.e., BP-3) in urine decreased with the age of adults (r = -0.410, p < 0.01) in the rural areas.

Modulation of Macrophage Polarization by Human Glomerular Mesangial Cells in Response to the Stimuli in Renal Microenvironment.

Mesangial cell (MC) activation and macrophage infiltration are 2 major events closely related with each other in mesangial proliferative glomerulonephritis. In the anti-Thy 1 nephritis model, macrophages mediate the damage and also the expansion of mesangium through secreting various inflammatory factors; however, in glomerular microenvironment how MCs affect macrophage activity in the presence of various stimuli have not yet been understood. In the present study, we found that resting human MCs (HMCs) constitutively expressed chemokine [C-C motif] ligand 2 (CCL-2) and interleukin (IL)-6 and induced M2 polarization of macrophages in the coculture system. HMC proliferation and migration and expression of IL-6, CCL-2, and macrophage colony-stimulating factor in HMCs were enhanced after platelet-derived growth factor (PDGF)-BB stimulation, among which CCL-2 was responsible for inducing the M2 polarization of macrophages. Furthermore, PDGF-BB-stimulated HMCs alleviated the classical activation of macrophages and drove more intensified M2 polarization of macrophages than resting HMCs did. However, lipopolysaccharide and interferon-γ (IFN-γ) stimulated HMCs maintained the M1 phenotype of cocultured macrophages. In conclusion, MCs actively participated in glomerular inflammation through influencing macrophage polarization. The interplay between MCs and infiltrated macrophages is finely modulated by secretory factors such as PDGF-BB and IFN-γ in response to the renal inflammatory microenvironment.

Urinary metabolites of organophosphate flame retardants in China: Health risk from tris(2-chloroethyl) phosphate (TCEP) exposure.

Organophosphate esters (OPs) are substitutes for polybrominated diphenyl ether (PBDE) flame retardants. China is the largest producer of OPs globally, with the production rate increasing at 15% annually. Since some OPs are neurodevelopmental and/or carcinogenic toxicants, human exposure is a concern. In this study, concentrations of eight OP metabolites (mOPs) were measured in human urine samples collected from 13 cities located in Northern, Eastern, Southern, and Southwestern China. All target mOPs were frequently detected with detection rates of 50% to 100%, indicating widespread human exposure to OPs. Bis(2-chloroethyl) phosphate (BCEP; median: 0.68 ng/mL), bis(1-chloro-2-propyl) phosphate (BCIPP; 0.30 ng/mL), diphenyl phosphate (DPHP; 0.30 ng/mL), and dibutyl phosphate (DBP; 0.29 ng/mL) were the dominant mOPs across all participants. Regional differences in concentrations (ΣmOPs varied from 0.86 to 3.7 ng/mL) and composition profiles (contribution of chlorinated mOPs to ΣmOPs varied from 35% to 95%) of mOPs were observed within China. In comparison to the concentrations reported worldwide, urinary DPHP and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) levels in China were lower, whereas BCEP and DBP levels were comparable or higher. The total daily intake (TDI) of tris(2-chloroethyl) phosphate (TCEP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP) were estimated from daily urine excretion rate and the fraction of OP metabolized in human liver microsomes (TDIHLM) or S9 fraction (TDIS9). The intake estimates showed that Chinese residents were exposed to TCEP from 96.9 to 46,700 (or 52.2 to 25,200) ng/kg bw/day. Depending on the reference dose, we found that approximately 5% of the individuals exceeded the limit (i.e., 2200 ng/kg bw/day) for TCEP intake. To our knowledge, this is the first nationwide baseline survey to determine urinary levels of mOPs in Chinese residents.