Neutrophil extracellular trap-mediated impairment of meningeal lymphatic drainage exacerbates secondary hydrocephalus after intraventricular hemorrhage.

Rationale: Hydrocephalus is a substantial complication after intracerebral hemorrhage (ICH) or intraventricular hemorrhage (IVH) that leads to impaired cerebrospinal fluid (CSF) circulation. Recently, brain meningeal lymphatic vessels (mLVs) were shown to serve as critical drainage pathways for CSF. Our previous studies indicated that the degradation of neutrophil extracellular traps (NETs) after ICH/IVH alleviates hydrocephalus. However, the mechanisms by which NET degradation exerts beneficial effects in hydrocephalus remain unclear. Methods: A mouse model of hydrocephalus following IVH was established by infusing autologous blood into both wildtype and Cx3cr1-/- mice. By studying the features and processes of the model, we investigated the contribution of mLVs and NETs to the development and progression of hydrocephalus following secondary IVH. Results: This study observed the widespread presence of neutrophils, fibrin and NETs in mLVs following IVH, and the degradation of NETs alleviated hydrocephalus and brain injury. Importantly, the degradation of NETs improved CSF drainage by enhancing the recovery of lymphatic endothelial cells (LECs). Furthermore, our study showed that NETs activated the membrane protein CX3CR1 on LECs after IVH. In contrast, the repair of mLVs was promoted and the effects of hydrocephalus were ameliorated after CX3CR1 knockdown and in Cx3cr1-/- mice. Conclusion: Our findings indicated that mLVs participate in the development of brain injury and secondary hydrocephalus after IVH and that NETs contribute to acute LEC injury and lymphatic thrombosis. CX3CR1 is a key molecule in NET-induced LEC damage and meningeal lymphatic thrombosis, which leads to mLV dysfunction and exacerbates hydrocephalus and brain injury. NETs may be a critical target for preventing the obstruction of meningeal lymphatic drainage after IVH.

[Effects of interleukin-17 antibody on polarization of macrophages in adipose tissue of high-fat diet fed mice exposed to bisphenol A].

OBJECTIVE: To investigate the effects of interleukin-17(IL-17) antibody on polarization of adipose tissue macrophages(ATM) in mice fed with high-fat diet(HFD) exposed to bisphenol A(BPA). METHODS: Four week-old male C57 BL/6 mice were divided into control group, IgG group, IL-17 antibody group, 1000 nmol/L BPA group, 1000 nmol/L BPA+IgG group, and 1000 nmol/L BPA+IL-17 antibody group according to random number table method. Eight mice per group were fed with HFD and BPA was exposed by drinking water. The IgG group and the 1000 nmol/L BPA+IgG group were intraperitoneally injected with 100 µg IgG antibody once a week, and the IL-17 group and the 1000 nmol/L BPA+IL-17 antibody group were intraperitoneally injected with 100 µg IL-17 antibody once a week. After 16 weeks, the mice were sacrificed, and serum samples were collected for serum separation. Leptin level was measured by enzyme-linked immunosorbent assay(ELISA). The expression of IL-1ß, IL-6 and monocyte chemoattractant protein-1(MCP-1)inflammatory cytokines were observed by immunohistochemistry(IHC) of adipose tissue of epididymis. The activity of inducible nitric oxide synthase(iNOS)and arginase-1(Arg-1)was measured by ELISA, and the proportion of M1 and M2 ATMs was measured by flow cytometry(FCM). The expression of CD11 c and CD206 mRNA was measured by qRT-PCR. RESULTS: Compared with the control group, serum leptin, the expressions of inflammatory cytokines IL-6, IL-1ß and MCP-1 in adipose tissue were increased in 1000 nmol/L BPA group, the proportion of M1 type ATM was increased(22.000%±0.500% vs. 31.467%±0.379%), iNOS activity was increased, CD11 c mRNA expression was increased, Arg-1 activity was decreased, CD206 mRNA expression was decreased, the differences were statistically significant(P<0.05), but the proportion of M2 type ATM was decreased insignificantly(P>0.05). There was no significant change in IgG group. Compared with 1000 nmol/L BPA group, IgG+1000 nmol/L BPA group had no significant change. In 1000 nmol/L BPA+IL-17 antibody group, serum leptin was decreased, the expressions of inflammatory factors IL-6, IL-1ß and MCP-1 in adipose tissue were down-regulated, and the proportion of M1 type ATM was decreased(31.467%±0.379% vs. 22.933%±0.153%), iNOS activity was decreased, CD11 c mRNA expression was decreased, and the proportion of M2 type ATM was increased(4.847%±0.655% vs. 7.840%±0.555%), Arg-1 activity was enhanced, and CD206 mRNA expression was up-regulated, the differences were statistically significant(P<0.05). CONCLUSION: IL-17 antibody may reduce the secretion of ATM inflammatory factors by inhibiting the polarization of ATM to M1 type, thus improving the inflammation of adipose tissue in BPA-infected HFD-fed mice.

Maternal vitamin D supplementation inhibits bisphenol A-induced proliferation of Th17 cells in adult offspring.

Bisphenol A (BPA) exposure can increase the risk of immune-related diseases in later life. Vitamin D3 (Vit D3) has been shown to have multiple immunomodulatory actions and has been used to treat immune diseases. However, the potential beneficial effects of Vit D3 on BPA-induced adverse effects in the immune system have not explored. We hypothesize that VitD3 may ameliorate BPA-induced side effects in the immune system, even in offspring of VitD3-supplemented mothers. Here, we established our experimental model by exposing pregnant dams with 1000 nM BPA with or without VitD3 (0.25 µg/kg, 1 µg/kg and 4 µg/kg) treatment. We show that mother's exposure to BPA increases proliferation of the spleen T helper 17 (Th17) cells and serum protein level of IL-17 in the offspring; however, VitD3 supplementation in mothers dose-dependently ameliorated these BPA-induced side effects on the immune system in the offspring as evidenced by attenuated upregulation of Th17 proliferation, and RORγt, IL-17, IL-6, and IL-23 expressions in the offspring. Our data provide the first evidence that maternal VitD3 supplementation offers benefits to the offspring by attenuating BPA-induced side effects on the immune system through vitamin D receptor (VDR)-dependent regulation of transcription factors and cytokines, suggesting its translational potential.

[Effects of bisphenol A on inflammation and Th17 cells in adipose tissue of high-fat fed mice].

OBJECTIVE: To study the effects of bisphenol A( BPA) on inflammation and Th17 cells in adipose tissue of high-fat fed mice. METHODS: 4-week-old male C57 BL /6mice were fed on high fat diet( HFD) and were administered 10, 100 and 1000 nmol / L BPA by drinking water. The normal diet( ND) and HFD control groups were set as well. Body weight of mice was recorded weekly. Mice were sacrificed at eighth and sixteenth week and epididymal fat pad was obtained. Hematoxylin-eosin( HE) staining was used to observe the cells morphological changes and inflammation in epididymal adipose tissue. Enzyme linked immunosorbent assay( ELISA) was used to detect TNF-α level in epididymal adipose tissue. Flow cytometry( FCM) was used to detect the proportion of Th17 cells in epididymal fat pad stromal vascular fractions( SVF). Immunohistochemistry( IHC) was used to detect the expression of IL-17 in epididymal adipose tissue. RESULTS: Compared with ND control groups, HFD increased body weight of mice, enhanced theinfiltration of inflammatory cells and the expression of TNF-α in adipose tissue. Also, the proportion of Th17 cells and the expression of IL-17 in adipose tissue were elevated. Compared with HFD control groups, BPA exposure enhanced the infiltration of inflammatory cells and the expression of TNF-α in adipose tissue. Also, the proportion of Th17 cells and the expression of IL-17 in adipose tissue were elevated in a dose-dependent way. And the effects at sixteenth week was more obvious than that at eighth week. CONCLUSION: BPA exposure can promote inflammation in adipose tissue of high-fat fed mice and elevate the proportion of Th17 cells and the expression of IL-17. Th17 cells may play an important role in the effects BPA on adipose tissue inflammation.

Gestational and lactational exposure to low-dose bisphenol A increases Th17 cells in mice offspring.

Increasing evidence demonstrates that perinatal exposure to Bisphenol A (BPA) can cause immune disorders throughout the life span. However, the biological basis for these immune disorders is poorly understood and the effects of exposure to BPA on Th17 development are unknown. The present study sought to characterize alterations of Th17 cells in childhood and adulthood following gestational and lactational exposure to environmentally relevant low-dose of BPA and the underlying mechanisms. Pregnant dams were exposed to BPA (10, 100 or 1000nM) via drinking water from gestational day (GD) 0 to postnatal day (PND) 21. At PNDs 21 and 42, offspring mice were anesthetized, blood was obtained for cytokine assay and spleens were collected for Th17 cell frequency and RORγt mRNA expression analysis. Perinatal exposure to low-dose BPA resulted in a dose-dependent and gender-specific persistent rise in Th17 cells accompanied by an increase of RORγt mRNA expression in the offsprings. The contents of major Th17 cell-derived cytokines (IL-17 and IL-21) and those essential for Th17 cell differentiation (IL-6 and IL-23) were also increased compared to those in controls. These changes were more pronounced in female than in male offsprings. However, perinatal exposure to low-dose BPA had little effect on serum TGF-ß, another key regulator for Th17 cell development. Our results suggest that gestational and lactational exposure to a low-dose of BPA can affect Th17 cell development via an action on its transcription factor and the regulatory cytokines. These findings provide novel insight into sustained immune disorders by BPA exposure during development.