Inorganic arsenic exposure induces E2F-dependent G0/G1 arrest via an increase in retinoblastoma family protein p130 in B-cell lymphoma A20 cells

Arsenic-induced transition of thymic inflammation-to-fibrosis involves Stat3-Twist1 interaction: Melatonin to the rescue

Groundwater arsenic is a notorious toxicant and exposure to environmentally relevant concentrations persists as a healthcare burden across the world. Arsenic has been reported to jeopardize the normal functioning of the immune system, but there are still gaps in the understanding of thymic T cell biology. Immunotoxic influence of arsenic in thymic integrity demands a potent restorative molecule. The objectives of this study were to examine key signaling cross-talks associated with arsenic-induced immune alterations in the thymus and propose melatonin as a potential candidate against immunological complications arising from arsenic exposure. Swiss albino mice were exposed to sodium arsenite (0.05 mg/L; in drinking water) and melatonin (IP:10 mg/kg BW) for 28 days. Melatonin successfully protected thymus from arsenic-mediated tissue degeneration and maintained immune homeostasis including T cell maturation and proliferation by mitigating oxidative stress through Nrf2 upregulation. Additionally, melatonin exerted ameliorative effect against arsenic-induced apoptosis and inflammation by inhibiting p53-mediated mitochondrial cell death pathway and NF-κB-p65/STAT3-mediated proinflammatory pathway, respectively. For the first time, we showed that arsenic-induced profibrotic changes were inhibited by melatonin through targeting of inflammation-associated EMT. Our findings clearly demonstrate that melatonin can be a viable and promising candidate in combating arsenic-induced immune toxicity with no collateral damage, making it an important research target.

Unveiling the link between arsenic toxicity and diabetes: an in silico exploration into the role of transcription factors

Arsenic-induced diabetes, despite being a relatively newer finding, is now a growing area of interest, owing to its multifaceted nature of development and the diversity of metabolic conditions that result from it, on top of the already complicated manifestation of arsenic toxicity. Identification and characterization of the common and differentially affected cellular metabolic pathways and their regulatory components among various arsenic and diabetes-associated complications may aid in understanding the core molecular mechanism of arsenic-induced diabetes. This study, therefore, explores the effects of arsenic on human cell lines through 14 transcriptomic datasets containing 160 individual samples using in silico tools to take a systematic, deeper look into the pathways and genes that are being altered. Among these, we especially focused on the role of transcription factors due to their diverse and multifaceted roles in biological processes, aiming to comprehensively investigate the underlying mechanism of arsenic-induced diabetes as well as associated health risks. We present a potential mechanism heavily implying the involvement of the TGF-β/SMAD3 signaling pathway leading to cell cycle alterations and the NF-κB/TNF-α, MAPK, and Ca2+ signaling pathways underlying the pathogenesis of arsenic-induced diabetes. This study also presents novel findings by suggesting potential associations of four transcription factors (NCOA3, PHF20, TFDP1, and TFDP2) with both arsenic toxicity and diabetes; five transcription factors (E2F5, ETS2, EGR1, JDP2, and TFE3) with arsenic toxicity; and one transcription factor (GATA2) with diabetes. The novel association of the transcription factors and proposed mechanism in this study may serve as a take-off point for more experimental evidence needed to understand the in vivo cellular-level diabetogenic effects of arsenic.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-024-00255-y.

Single-cell RNA sequencing reveals placental response under environmental stress

The placenta is crucial for fetal development, yet the impact of environmental stressors such as arsenic exposure remains poorly understood. We apply single-cell RNA sequencing to analyze the response of the mouse placenta to arsenic, revealing cell-type-specific gene expression, function, and pathological changes. Notably, the Prap1 gene, which encodes proline-rich acidic protein 1 (PRAP1), is significantly upregulated in 26 placental cell types including various trophoblast cells. Our study shows a female-biased increase in PRAP1 in response to arsenic and localizes it in the placenta. In vitro and ex vivo experiments confirm PRAP1 upregulation following arsenic treatment and demonstrate that recombinant PRAP1 protein reduces arsenic-induced cytotoxicity and downregulates cell cycle pathways in human trophoblast cells. Moreover, PRAP1 knockdown differentially affects cell cycle processes, proliferation, and cell death depending on the presence of arsenic. Our findings provide insights into the placental response to environmental stress, offering potential preventative and therapeutic approaches for environment-related adverse outcomes in mothers and children.

Arsenite exposure induces premature senescence and senescence-associated secretory phenotype (SASP) in human hepatocyte-derived cell line Huh-7

BACKGROUND

Chronic arsenite exposure has been known to induce cancer in various organs; however, the underlying mechanisms remain elusive. The characteristic feature of carcinogenesis due to arsenic exposure is that the disease develops after a prolonged latent period, even after cessation of exposure. Our previous study revealed that arsenite exposure induces premature senescence in hepatic stellate cells and suggests that the senescence-associated secretory phenotype (SASP) factors from the senescent cells promote hepatic carcinogenesis. However, arsenite exposure in the liver occurs not only in hepatic stellate cells, but also in hepatocytes. Therefore, we examined whether arsenite exposure in hepatocytes also causes premature senescence and the enhancement of SASP factors. We also assessed whether those effects remained after cessation of arsenite exposure.

METHODS

Human hepatocyte-derived cell line Huh-7 was exposed to sodium arsenite for 72 hours to determine the concentration at which cell proliferation was inhibited. In the 5 µM of exposure, various cellular senescence markers and SASP factors were analyzed and compared with unexposed cells. We also examined whether those senescence markers and SASP factors were maintained after cessation of arsenite exposure. Finally, we explored whether the increased expression of SASP factor, which was upregulated in hepatocytes by arsenic exposure in this study, is related to the prognosis of human hepatocellular carcinoma.

RESULTS

After exposure to 5 µM of sodium arsenite for 72 hours, various senescent features, such as the induction of P21 mRNA, the reduction of LAMINB1 mRNA, morphological changes, phosphorylation of P53, and the presence of SA-β-gal positive cells were observed. Those changes were maintained after cessation of arsenite exposure. In addition, mRNA levels of SASP factors (MMP1, MMP3, MMP10, GDF15, PAI-1, and IL-6) were increased after arsenite exposure, and their high expression levels were maintained after cessation of arsenite exposure. Furthermore, by analyzing the TCGA database, we found that the increased expression levels of many SASP factors negatively correlated with prognosis.

CONCLUSIONS

Arsenite exposure induces premature senescence in hepatocyte-derived cells and increases SASP factors that are related to hepatic tumorigenesis. Once arsenite exposure induces premature senescence, the senescent cells remain even after cessation of exposure.

Conformal Nanoencapsulation of Allogeneic T Cells Mitigates Graft-versus-Host Disease and Retains Graft-versus-Leukemia Activity

Allogeneic transplantation of hematopoietic stem cells (HSC) in combination with T cells has a curative potential for hematopoietic malignancies through graft-versus-leukemia (GVL) effects, but is often compromised by the notorious side effect of graft-versus-host disease (GVHD) resulting from alloreactivity of the donor T cells. Here, we tested if temporary immunoisolation achieved by conformally encapsulating the donor T cells within a biocompatible and biodegradable porous film (∼450 nm in thickness) of chitosan and alginate could attenuate GVHD without compromising GVL. The nanoencapsulation was found not to affect the phenotype of T cells in vitro in terms of size, viability, proliferation, cytokine secretion, and cytotoxicity against tumor cells. Moreover, the porous nature of the nanoscale film allowed the encapsulated T cells to communicate with their environment, as evidenced by their intact capability of binding to antibodies. Lethally irradiated mice transplanted with bone marrow cells (BMCs) and the conformally encapsulated allogeneic T cells exhibited significantly improved survival and reduced GVHD together with minimal liver damage and enhanced engraftment of donor BMCs, compared to the transplantation of BMCs and non-encapsulated allogeneic T cells. Moreover, the conformal nanoencapsulation did not compromise the GVL effect of the donor T cells. These data show that conformal nanoencapsulation of T cells within biocompatible and biodegradable nanoscale porous materials is a potentially safe and effective approach to improve allogeneic HSC transplantation for treating hematological malignancies and possibly other diseases.

Clinical significance of expression of ZIC1 and P130 in cholangiocarcinoma

AIM: To investigate the expression of zicfamilymember1 (ZIC1) and P130 in cholangiocarcinoma and their correlation with the biological behavior of cholangiocarcinoma.

METHODS: The protein expression of ZIC1 and P130 was detected by immunohistochemistry in 43 cases of cholangiocarcinoma and 20 cases of normal bile duct tissue.

RESULTS: The positive rate of ZIC1 expression was significantly higher in cholangiocarcinoma than in normal bile duct tissue (53.49% vs 25.00%, P < 0.05). The positive rate of P130 expression in cholangiocarcinoma was significantly lower than that in normal bile duct tissue (55.81 vs 85.00%, P < 0.05). The expression of ZIC1 and P130 protein was related to pathological grade and neoplasm metastasis (both P < 0.05), but not to sex or Nevin stage (both P > 0.05). There was a negative correlation between ZIC1 and P130 expression (r = -0.360, P < 0.05) in cholangiocarcinoma. The expression of ZIC1 and P130 proteins was related to the 3-year survival rate (both P < 0.05).

CONCLUSION: The abnormal expression of ZIC1 and P130 proteins may be involved in the development and progression of cholangiocarcinoma.