Effects of developmental exposures to Bisphenol-A and Bisphenol-S on hepatocellular function in male Long-Evans rats

Bisphenol-S (BPS) is a current substitute for Bisphenol-A (BPA) in various commercial products (paper, plastics, protective can-coatings, etc.) used by all age groups globally. The current literature indicates that a drastic surge in pro-oxidants, pro-apoptotic, and pro-inflammatory biomarkers in combination with diminished mitochondrial activity can potentially decrease hepatic function leading to morbidity and mortality. Consequently, there are increasing public health concerns that substantial Bisphenol-mediated effects may impact hepatocellular functions, particularly in newborns exposed to BPA and BPS postnatally. However, the acute postnatal impact of BPA and BPS and the molecular mechanisms affecting hepatocellular functions are unknown. Therefore, the current study investigated the acute postnatal effect of BPA and BPS on the biomarkers of hepatocellular functions, including oxidative stress, inflammation, apoptosis, and mitochondrial activity in male Long-Evans rats. BPA and BPS (5 and 20 microgram/Liter (μg/L) of drinking water) were administered to 21-day-old male rats for 14 days. BPS had no significant effect on apoptosis, inflammation, and mitochondrial function but significantly reduced the reactive oxygen species (51-60 %, **p < 0.01) and nitrite content (36 %, *p < 0.05), exhibiting hepatoprotective effects. As expected, based on the current scientific literature, BPA induced significant hepatoxicity, as seen by significant glutathione depletion (50 %, *p < 0.05). The in-silico analysis indicated that BPS is effectively absorbed in the gastrointestinal tract without crossing the blood-brain barrier (whereas BPA crosses the blood-brain barrier) and is not a substrate of p-Glycoprotein and Cytochrome P450 enzymes. Thus, the current in-silico and in vivo findings revealed that acute postnatal exposure to BPS had no significant hepatotoxicity.

Gefitinib Inhibits Rifampicin-Induced CYP3A4 Gene Expression in Human Hepatocytes

During multidrug combination chemotherapy, activation of the nuclear receptor and the transcription factor human pregnane xenobiotic receptor (hPXR) has been shown to play a role in the development of chemoresistance. Mechanistically, this could occur due to the cancer drug activation of hPXR and the subsequent upregulation of hPXR target genes such as the drug metabolism enzyme, cytochrome P450 3A4 (CYP3A4). In the context of hPXR-mediated drug resistance, hPXR antagonists would be useful adjuncts to PXR-activating chemotherapy. However, there are currently no clinically approved hPXR antagonists in the market. Gefitinib (GEF), a tyrosine kinase inhibitor used for the treatment of advanced non-small-cell lung cancer and effectively used in combinational chemotherapy treatments, is a promising candidate owing to its hPXR ligand-like features. We, therefore, investigated whether GEF would act as an hPXR antagonist when combined with a known hPXR agonist, rifampicin (RIF). At therapeutically relevant concentrations, GEF successfully inhibited the RIF-induced upregulation of endogenous CYP3A4 gene expression in human primary hepatocytes and human hepatocells. Additionally, GEF inhibited the RIF induction of hPXR-mediated CYP3A4 promoter activity in HepG2 human liver carcinoma cells. The computational modeling of molecular docking predicted that GEF could bind to multiple sites on hPXR including the ligand-binding pocket, allowing for potential as a direct antagonist as well as an allosteric inhibitor. Indeed, GEF bound to the ligand-binding domain of the hPXR in cell-free assays, suggesting that GEF directly interacts with the hPXR. Taken together, our results suggest that GEF, at its clinically relevant therapeutic concentration, can antagonize the hPXR agonist-induced CYP3A4 gene expression in human hepatocytes. Thus, GEF could be a potential candidate for use in combinational chemotherapies to combat hPXR agonist-induced chemoresistance. Further studies are warranted to determine whether GEF has sufficient hPXR inhibitor abilities to overcome the hPXR agonist-induced chemoresistance.

Early transcriptomic response of mouse adrenal gland and Y-1 cells to dexamethasone

Glucocorticoids have short- and long-term effects on adrenal gland function and development. RNA sequencing (RNA-seq) was performed to identify early transcriptomic responses to the synthetic glucocorticoid, dexamethasone (Dex), in vitro and in vivo. In total, 1711 genes were differentially expressed in the adrenal glands of the 1-h Dex-treated mice. Among them, only 113 were also considered differentially expressed genes (DEGs) in murine adrenocortical Y-1 cells treated with Dex for 1 h. Gene ontology analysis showed that the upregulated DEGs in the adrenal gland of the 1-h Dex-treated mice were highly associated with the development of neuronal cells, suggesting the adrenal medulla had a rapid response to Dex. Interestingly, only 4.3% of Dex-responsive genes in the Y-1 cell line under Dex treatment for 1 h were differentially expressed under Dex treatment for 24 h. The heatmaps revealed that most early responsive DEGs in Y-1 cells during 1 h of treatment exhibited a transient response. The expression of these genes under treatment for 24 h returned to basal levels similar to that during control treatment. In summary, this research compared the rapid transcriptomic effects of Dex stimulation in vivo and in vitro. Notably, adrenocortical Y-1 cells had a transient early response to Dex treatment. Furthermore, the DEGs had a minimal overlap in the 1-h Dex-treated group in vivo and in vitro.

Cardioprotective Effects of Oroxylum indicum Extract Against Doxorubicin and Cyclophosphamide-Induced Cardiotoxicity

Administration of Chemotherapeutics, especially doxorubicin (DOX) and cyclophosphamide (CPS), is commonly associated with adverse effects such as myelosuppression and cardiotoxicity. At this time, few approved therapeutic options are currently available for the management of chemotherapy-associated cardiotoxicity. Thus, identification of novel therapeutics with potent cardioprotective properties and minimal adverse effects are pertinent in treating Doxorubicin and Cyclophosphamide-induced cardiotoxicity. Oroxylum indicum extract (OIE, Sabroxy®) is a natural product known to possess several beneficial biological functions including antioxidant, anti-inflammatory and cytoprotective effects. We therefore set to investigate the cardioprotective effects of OIE against Doxorubicin and Cyclophosphamide-induced cardiotoxicity and explore the potential cardioprotective mechanisms involved. Adult male mice were treated with DOX and CPS in combination, OIE alone, or a combination of OIE and DOX & CPS. Swimming test was performed to assess cardiac function. Markers of oxidative stress were assessed by levels of reactive oxygen species (ROS), nitrite, hydrogen peroxide, catalase, and glutathione content. The activity of interleukin converting enzyme and cyclooxygenase was determined as markers of inflammation. Mitochondrial function was assessed by measuring Complex-I activity. Apoptosis was assessed by Caspase-3 and protease activity. Mice treated with DOX and CPS exhibited reduced swim rate, increased oxidative stress, increased inflammation, and apoptosis in the heart tissue. These cardiotoxic effects were significantly reduced by co-administration of OIE. Furthermore, computational molecular docking studies revealed potential binding of DOX and CPS to tyrosine hydroxylase which validated our in vivo findings regarding the inhibition of tyrosine hydroxylase activity. Our current findings indicated that OIE counteracts Doxorubicin and Cyclophosphamide-induced cardiotoxicity-through inhibition of ROS-mediated apoptosis and by blocking the effect on tyrosine hydroxylase. Taken together, our findings suggested that OIE possesses cardioprotective effects to counteract potentially fatal cardiac complications associated with chemotherapy treatment.

A clinically relevant combination treatment with doxorubicin and cyclophosphamide does not induce hepatotoxicity in C57BL/6J mice

BACKGROUND AND AIM

Chronic exposure to chemotherapeutics can lead to severe adverse events including hepatotoxicity. A combination chemotherapy regimen of doxorubicin (DOX) and cyclophosphamide (CPS) is employed in treatment of several cancers such as leukemia, lymphoma, and breast cancer. It is not well understood whether a combination therapy of DOX and CPS can induce hepatotoxicity. We therefore sought to determine whether co-administration of DOX and CPS at their clinically relevant doses and frequency results in hepatotoxicity.

METHODS

Male C57BL/6J mice received one intraperitoneal injection of saline or DOX-2mg /kg and CPS-50mg/kg once a week for 4 weeks. After the treatment period, liver histology and various serum biomarkers of hepatotoxicity were assessed.

RESULTS

Co-treatment of DOX and CPS did not alter the serum levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), bilirubin, albumin, globulin, or total protein. Similarly, co-administration of DOX and CPS did not result in a noticeable change in liver histology. However, it was notable that the concomitant treatment with DOX and CPS resulted in a significant increase in serum levels of aspartate aminotransferase (AST). Elevated serum AST levels were also associated with increased serum creatinine kinase (CK) levels, suggesting that the elevated serum AST levels are likely due to muscle injury following the co-administration of DOX and CPS.

CONCLUSION

Taken together, our results, for the first time, suggest that co-administration of DOX and CPS, at their clinically relevant doses and frequency does not induce a significant hepatotoxicity in the mice.

Oroxylum indicum extract, at a physiologically relevant dosage, does not induce hepatotoxicity in C57BL/6J mice

Background

Botanical supplements have been proven to provide beneficial health effects. However, they can induce unintended adverse events such as hepatotoxicity. Oroxylum indicum extract (OIE, Sabroxy®) has several health benefits including anti-inflammatory, anti-arthritic, antifungal, antibacterial, and neuroprotective effects. It is currently unknown whether OIE has the potential to induce hepatotoxicity.

Purpose

In the current study, we sought to determine whether OIE can induce hepatotoxicity in C57BL/6J mouse model.

Methods

The male mice were fed powdered rodent food (control group) or powdered rodent food mixed with OIE (Sabroxy®, 500mg/kg) daily for 4 weeks. Following the treatment, we assessed liver histology and serum levels of biomarkers commonly associated with liver damage, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP).

Results

No significant alterations were observed in liver histology, and serum levels of ALT, AST, ALP, bilirubin, albumin, globulin and total protein in the OIE fed mice compared to the control mice.

Conclusion

Taken together, our results suggest that OIE, when fed at its physiologically relevant dosage, does not induce hepatotoxicity in C57BL/6J mice.

Dysregulation of Endobiotic Homeostasis Mechanisms: Novel Insights into Adverse Pharmacokinetic Interactions between Illicit Substances and Clinical Drugs

Many patients with a variety of medical conditions take illicit substances concomitantly with clinical drugs. This concomitant usage can lead to life-threatening adverse events. Despite the evidence that these adverse events can be caused by pharmacokinetic interactions, the underlying mechanisms are poorly understood. Investigation of mechanisms involved in dysregulation of endobiotic homeostasis during the concomitant usage of illicit substances with clinical drugs could provide novel insights into pharmacokinetic mechanisms of adverse interactions between illicit substances and clinical drugs.