Environmental perchlorate, thiocyanate, and nitrate exposures and bone mineral density: a national cross-sectional study in the US adults.

Associations of perchlorate, thiocyanate, and nitrate exposures with bone mineral density (BMD) in adults have not previously been studied. This study aimed to estimate the associations of individual and concurrent exposure of the three chemicals with adult BMD. Based on National Health and Nutrition Examination Survey (NHANES, 2011-2018), 1618 non-pregnant adults (age ≥ 20 years and 47.0% female) were included in this study. Survey-weighted linear regression models were used to estimate individual urinary perchlorate, thiocyanate, and nitrate concentrations with lumbar spine BMD and total BMD in adults. Then, weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) models were conducted to evaluate associations of co-occurrence of the three chemicals with adult BMD. In all participants, nitrate exposure was inversely associated with lumbar spine BMD (ß = - 0.054, 95%CI: - 0.097, - 0.010). In stratification analyses, significant inverse associations were observed in female and participants older than 40 years old. In WQS regressions, significant negative associations of the weighted sum of the three chemicals with total and lumbar spine BMD (ß = - 0.014, 95%CI: - 0.021, - 0.007; ß = - 0.011, 95%CI: - 0.019, - 0.004, respectively) were found, and the dominant contributor was nitrate. In the BKMR models, non-linear dose-response associations of nitrate exposure with lumbar spine and total BMD were observed. These findings suggested that environmental perchlorate, thiocyanate, and nitrate exposure may reduce adult BMD and nitrate is the main contributor.

Airborne fine particles drive H1N1 viruses deep into the lower respiratory tract and distant organs.

Mounting data suggest that environmental pollution due to airborne fine particles (AFPs) increases the occurrence and severity of respiratory virus infection in humans. However, it is unclear whether and how interactions with AFPs alter viral infection and distribution. We report synergetic effects between various AFPs and the H1N1 virus, regulated by physicochemical properties of the AFPs. Unlike infection caused by virus alone, AFPs facilitated the internalization of virus through a receptor-independent pathway. Moreover, AFPs promoted the budding and dispersal of progeny virions, likely mediated by lipid rafts in the host plasma membrane. Infected animal models demonstrated that AFPs favored penetration of the H1N1 virus into the distal lung, and its translocation into extrapulmonary organs including the liver, spleen, and kidney, thus causing severe local and systemic disorders. Our findings revealed a key role of AFPs in driving viral infection throughout the respiratory tract and beyond. These insights entail stronger air quality management and air pollution reduction policies.

Computer-Aided Discovery of Potent Broad-Spectrum Vaccine Adjuvants.

Adjuvants stimulate the immune system to vigorously respond to a vaccine. While current adjuvants such as aluminum salts and oil-in-water emulsions have been used for decades, they do not generate broad and long-lasting responses in many vaccines. Consequently, more potent adjuvants are needed. Here, using computer-aided molecule design and machine learning, we discovered 2 new, broad-spectrum adjuvants that can boost vaccine responses. Our library containing 46 toll-like receptor (TLR)-targeting agonist ligands were assembled on Au nanoparticles. Comprehensive in vitro, ex vivo and in vivo studies showed both leads promoted dendritic cell activation via multiple TLRs and enhanced antigen presentation to T cells. When used together with tumor-specific antigens to immunize mice against B16-OVA melanoma and 4T1-PD1 breast cancer, both adjuvants unleashed strong immune responses that suppressed tumor growth and lung metastases. Our results show computer-aided design and screening can rapidly uncover potent adjuvants for tackling waning immunity in current vaccines.

Newly identified lncRNA-45 promotes breast cancer metastasis through activating the mTOR signaling pathway.

BACKGROUND: Metastasis, a complex multi-stage process, is the primary cause of breast cancer-related death. Unfortunately, the molecular mechanisms underlying tumor metastasis have not been fully elucidated thus far. Long noncoding RNAs (lncRNAs) dictate the behaviours of tumor cells via multiple signaling pathways, resulting in tumor cell migration and invasion, as well as all stages of cancer progression. LncRNAs function as regulators in shaping cellular activities directly through influencing key genes involved in biological processes of the tumor, and representing promising novel targets in cancer diagnosis and therapy. We therefore sought to define the correlations between lncRNA expression and breast cancer metastasis, especially to investigate the functional pathway underlying lncRNA-mediated tumor invasion and metastasis process. RESULTS: In this study, we compared the lncRNA transcriptome profiles between primary breast cancer 4T1 cells and high metastatic 4T1-LG12 cells. We found that many differently expressed lncRNAs greatly correlated to the metastatic propensity of 4T1-LG12 cells, particularly lncRNA-45, a new lncRNA without functional annotations, which was found to be the most upregulated lncRNA transcribed by an internal region within the regulatory associated with protein of mechanistic target of rapamycin kinase (mTOR) complex 1 (Rptor) gene. LncRNA-45 was uncovered to be involved in the epithelial-to-mesenchymal transition process of breast cancer cells, as evidenced by the observation that lncRNA-45 knockdown significantly suppressed the invasive capability of parental 4T1-LG12 cells. Molecular mechanistic investigation showed that reduced activity of mTORC1-associated pathway led to a decrease of total ribosomal protein S6 kinase, polypeptide 1 (S6K1) content and enhancement of autophagy, consequently compromising the metastatic propensity in lncRNA-45 knockdown cells. CONCLUSIONS: Overall, our experiments uncovered that the newly identified lncRNA-45 played a regulatory role in breast cancer cell metastasis.

Endothelial Dysfunction and Platelet Hyperactivation in Diabetic Complications Induced by Glycemic Variability.

The development and progression of the complications of chronic diabetes mellitus are attributed not only to increased blood glucose levels but also to glycemic variability. Therefore, a deeper understanding of the role of glycemic variability in the development of diabetic complications may provide more insight into targeted clinical treatment strategies in the future. Previously, the mechanisms implicated in glycemic variability-induced diabetic complications have been comprehensively discussed. However, endothelial dysfunction and platelet hyperactivation, which are two newly recognized critical pathogenic factors, have not been fully elucidated yet. In this review, we first evaluate the assessment of glycemic variability and then summarise the roles of endothelial dysfunction and platelet hyperactivation in glycemic variability-induced complications of diabetes, highlighting the molecular mechanisms involved and their interconnections.

Binding of Benzo[a]pyrene Alters the Bioreactivity of Fine Biochar Particles toward Macrophages Leading to Deregulated Macrophagic Defense and Autophagy.

Contaminant-bearing fine biochar particles (FBPs) may exert significantly different toxicity profiles from their contaminant-free counterparts. While the role of FBPs in promoting contaminant uptake has been recognized, it is unclear whether the binding of contaminants can modify the biochemical reactivity and toxicological profiles of FBPs. Here, we show that binding of benzo[a]pyrene (B(a)P, a model polycyclic aromatic hydrocarbon) at environmentally relevant exposure concentrations markedly alters the cytotoxicity of FBPs to macrophages, an important line of innate immune defense against airborne particulate matters (PMs). Specifically, B(a)P-bearing FBPs elicit more severe disruption of the phospholipid membrane, endocytosis, oxidative stress, autophagy, and compromised innate immune defense, as evidenced by blunted proinflammatory effects, compared with B(a)P-free FBPs. Notably, the altered cytotoxicity cannot be attributed to the dissolution of B(a)P from the B(a)P-bearing FBPs, but appears to be related to B(a)P adsorption-induced changes of FBPs bioreactivity toward macrophages. Our findings highlight the significance of environmental chemical transformation in altering the bioreactivity and toxicity of PMs and call for further studies on other types of carbonaceous nanoparticles and additional exposure scenarios.

A Designed α-GalCer Analog Promotes Considerable Th1 Cytokine Response by Activating the CD1d-iNKT Axis and CD11b-Positive Monocytes/Macrophages.

Selective helper T cell 1 (Th1) priming agonists are a promising area of investigation for immunotherapeutic treatment of various diseases. α-galactosylceramide (α-GalCer, KRN7000), a well-studied Th1-polarizer, simultaneously induces helper T cell 2 (Th2)-type responses, which is a major drawback for its clinical applications. Based on surflex-docking computation, α-GalCer-diol, with added hydroxyl groups in the acyl chain, is designed and synthesized. Structural analyses reveal stronger affinity between α-GalCer-diol and cluster of differentiation 1d (CD1d), leading to enhanced antigen presentation by dendritic cells (DCs) and self-activation, as reflected by tight binding of the T-cell receptor (TCR)/KRN7000/CD1d ternary complex and elevated production of interleukin 12 (IL-12) and interferon-γ (IFN-γ). Consequently, invariant natural killer T cells (iNKTs) are activated and exhibit an improved Th1-type cytokine profile ex vivo and in vivo. Different from KRN7000, α-GalCer-diol markedly boosts the expansion of the CD11b+ subpopulation and enhances IFN-γ content in CD11b+ cells. These reinforced Th1-type responses collectively endow α-GalCer-diol more robust antitumor activity in a xenograft animal model using B16-F10 melanoma cells. Together, the data demonstrate a new mechanism through which α-GalCer-diol induces stronger Th1-type responses by stimulating CD11b+ leukocyte expansion and DC-conducted CD1d-restricted and TCR-mediated iNKT activation. Hence, this study may facilitate the development of novel Th1 priming agonists.

Nanoscale perfluorocarbon expediates bone fracture healing through selectively activating osteoblastic differentiation and functions.

BACKGROUND AND RATIONALE: Fracture incidence increases with ageing and other contingencies. However, the strategy of accelerating fracture repair in clinical therapeutics remain a huge challenge due to its complexity and a long-lasting period. The emergence of nano-based drug delivery systems provides a highly efficient, targeted and controllable drug release at the diseased site. Thus far, fairly limited studies have been carried out using nanomedicines for the bone repair applications. Perfluorocarbon (PFC), FDA-approved clinical drug, is received increasing attention in nanomedicine due to its favorable chemical and biologic inertness, great biocompatibility, high oxygen affinity and serum-resistant capability. In the premise, the purpose of the current study is to prepare nano-sized PFC materials and to evaluate their advisable effects on promoting bone fracture repair. RESULTS: Our data unveiled that nano-PFC significantly enhanced the fracture repair in the rabbit model with radial fractures, as evidenced by increased soft callus formation, collagen synthesis and accumulation of beneficial cytokines (e.g., vascular endothelial growth factor (VEGF), matrix metalloprotein 9 (MMP-9) and osteocalcin). Mechanistic studies unraveled that nano-PFC functioned to target osteoblasts by stimulating their differentiation and activities in bone formation, leading to accelerated bone remodeling in the fractured zones. Otherwise, osteoclasts were not affected upon nano-PFC treatment, ruling out the potential target of nano-PFC on osteoclasts and their progenitors. CONCLUSIONS: These results suggest that nano-PFC provides a potential perspective for selectively targeting osteoblast cell and facilitating callus generation. This study opens up a new avenue for nano-PFC as a promising agent in therapeutics to shorten healing time in treating bone fracture.

Neonatal exposure to organophosphorus flame retardant TDCPP elicits neurotoxicity in mouse hippocampus via microglia-mediated inflammation in vivo and in vitro.

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is a phosphorus-based flame retardant common in consumer goods and baby products. Concerns have been raised about TDCPP exposure and neurodevelopmental toxicity. However, the mechanism and early response for TDCPP-induced neurotoxicity are poorly understood. This study investigates the role of microglia-mediated neuroinflammation in TDCPP-induced neurotoxicity in mice and primary cells. TDCPP was administered to C57BL/6 pups (0, 5, or 50 mg/kg/day) via an oral gavage from postnatal days 10-38 (28 days). The results showed that TDCPP exposure for 28 days altered the gene expression of neuronal markers Tubb3, Nefh, and Nes, and led to apoptosis in the hippocampus. The mRNA levels of pro-inflammatory factors Il-1ß, Tnfα and Ccl2 dose dependently increased in the hippocampus at both 24 h and 28 days following exposure, accompanied by microglia activation characterized by an amoeboid-like phenotype. In in vitro studies using the primary microglia isolated from neonatal mice, exposure to TDCPP (0-100 µM) for 24 h resulted in cellular activation. It also increased the expression of genes responsible for inflammatory responses including surface markers and pro-inflammatory cytokines. These changes occurred in a dose-dependent fashion. Neurite outgrowth of primary mouse hippocampal neurons was inhibited by treatment with the conditioned medium harvested from microglia exposed to TDCPP. These results reveal that neonatal exposure to TDCPP induces neuronal damage through microglia-mediated inflammation. This provides insight into the mechanism of TDCPP's neurodevelopmental toxicity, and suggests that microglial cell is a sensitive responder for OPFRs exposure.

Developmental exposure to BDE-99 hinders cerebrovascular growth and disturbs vascular barrier formation in zebrafish larvae.

Polybrominated diphenyl ethers (PBDEs) are distributed throughout the environment. Despite a moratorium on their use, concentrations of PBDEs in the atmosphere and in residential environments remain high due to their persistence. The environmental health risks remain concerning and one of the major adverse effects is neurodevelopmental toxicity. However, the early response and effects of PBDEs exposure on the developing brain remain unknown. In the present study, we investigated the impacts of 2,2',4,4',5-pentabrominated diphenyl ether (BDE-99) on vascular growth and vascular barrier function with an emphasis on cerebral blood vessels, in the early life stages, using a zebrafish model. No general toxicity was observed in exposing zebrafish larvae to 0-0.5 µM BDE-99 at 72 hpf. BDE-99 exposure resulted in neither general toxicity nor pronounced developmental impairment in somatic blood vessels, including intersegmental vessels (ISV) and common cardinal veins (CCV). Meanwhile, both 0.05 µM and 0.5 µM of BDE-99 reduced cerebrovascular density as well as down-regulation of VEGFA and VEGFR2 in the head. In addition, BDE-99 exposure increased vascular leakage, both in cerebral and truncal vasculature at 72 hpf. The accentuated vascular permeability was observed in the head. The mRNA levels of genes encoding tight junction molecules decreased in the BDE-99-exposed larvae, and more robust reductions in Cldn5, Zo1 and Jam were detected in the head than in the trunk. Moreover, proinflammatory factors including TNF-α, IL-1ß and ICAM-1 were induced, and the expression of neurodevelopment-related genes was suppressed in the head following BDE-99 exposure. Taken together, these results reveal that developmental exposure to BDE-99 impedes cerebrovascular growth and disturbs vascular barrier formation. The cerebral vasculature in developing zebrafish, a more sensitive target for BDE-99, may be a promising tool for the assessment of the early neurodevelopmental effects due to PBDEs exposure.

Exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCPP) induces vascular toxicity through Nrf2-VEGF pathway in zebrafish and human umbilical vein endothelial cells.

The growing production and extensive use of organophosphate flame retardants (OPFRs) have led to an increase in their environmental distribution and human exposure. Developmental toxicity is a major concern of OPFRs' adverse health effects. However, the impact of OPFRs exposure on vascular development and the toxicity pathway for developmental defects are poorly understood. In this study, we investigated the effects of exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCPP), a frequently detected OPFR, on early vascular development, and the possible role of nuclear factor erythroid 2-related factor (Nrf2)-dependent angiogenic pathway in TDCPP's vascular toxicity. TDCPP exposure at 300 and 500 µg/L impeded the growth of intersegmental vessels (ISV), a type of microvessels, as early as 30 hpf. Consistently, a similar pattern of decreased extension and remodeling of common cardinal vein (CCV), a typical macrovessel, was observed in zebrafish at 48 hpf and 72 hpf. Developing vasculature in zebrafish was more sensitive than general developmental parameters to TDCPP exposure. The expression of genes related to VEGF signaling pathway dose-dependently decreased in TDCPP-treated larvae. In in vitro experiments using human umbilical vein endothelial cells (HUVECs), the increased cell proliferation induced by VEGF was suppressed by TDCPP exposure in a dose-dependent fashion. In addition, we found a repression of Nrf2 expression and activity in TDCPP-treated larvae and HUVECs. Strikingly, the application of CDDO-Im, a potent Nrf2 activator, enhanced VEGF and protected against defective vascular development in zebrafish. Our results reveal that vascular impairment is a sensitive index for early exposure to TDCPP, which could be considered in the environmental risk assessment of OPFRs. The identification of Nrf2-mediating VEGF pathway provides new insight into the adverse outcome pathway (AOP) of OPFRs.

Waterborne exposure to low concentrations of BDE-47 impedes early vascular development in zebrafish embryos/larvae.

Polybrominated diphenyl ethers (PBDEs) are persistent flame retardants ubiquitously existing in various environment matrices. In spite of a recent reduction in use according to the phase-out policy, high levels of PBDEs are still found in both environmental and biological samples due to their persistent property and large-scale production over a long history. Developmental toxicity is a major health concern of PBDEs. However, the impact of PBDE exposure on vascular development remains poorly understood. In this study, we investigated the effect of low concentrations of 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47), a predominant PBDE congener, in environmental matrices and biota, on early vascular development using zebrafish. Zebrafish embryos were continuously exposed to waterborne BDE-47 at 0.06, 0.2, 0.6 µM starting from 2 h post-fertilization (hpf). Fluorescent images of vasculatures in Tg(kdrl:eGFP) zebrafish were acquired using a confocal microscope. The results indicated that BDE-47 exposure had no effect on hatching rate, survival, body weight, body length or heart rate in the early stage within 72 hpf, whereas zebrafish exposed to BDE-47 exhibited impairments in the growth of multiple types of blood vessels. The percentage of completed intersegmental vessels (ISV) at 30 hpf decreased in embryos treated with BDE-47 in a dose-dependent fashion. BDE-47 exposure led to a slight decrease in the growth of common cardinal vein (CCV), while dramatically hindered CCV remodeling process reflected by the larger CCV area and wider ventral diameter. BDE-47 exposure significantly reduced sub-intestinal vessels (SIV) area as well as the vascularized yolk area in zebrafish larvae at 72 hpf. In addition, the expression of genes related to vascular growth and remodeling was markedly suppressed in BDE-47-exposed zebrafish. These findings demonstrate the adverse effects of BDE-47 on early vascular development, and confirm the vascular toxicity of PBDEs in vivo. The results indicate that developing vasculature in zebrafish is sensitive to BDE-47 exposure, and may serve as a powerful tool for the assessment of early exposure to PBDEs.