Abcb1a and Abcb1b genes function differentially in blood-testis barrier dynamics in the rat

Unveiling the role of sex in the metabolism of indoxyl sulfate and apixaban

Chronic Kidney Disease (CKD) is associated with heightened risk of thrombosis. Prescription of anticoagulants is key to manage it; however, CKD patients have shown an increased risk of bleeding under anticoagulation therapy compared to non-CKD patients. We hypothesized that the sex could modify the metabolism of indoxyl sulfate (IS), a uremic toxin and Apixaban. Our intoxication model shows that higher doses of IS and apixaban accumulate in the plasma of female mice because of expression differences in efflux transporters and cytochromes in the liver, ileum and kidneys, when compared to males. Furthermore, we found that accumulation of apixaban in females contributes to increased bleeding. Transcriptional analysis of liver samples revealed elevated Sult1a1 but reduced Abcg2 and Cyp3a11 in female mice, while in the kidneys the expression rates of Oat1 and Oat3 were respectively lower and higher than those observed in males, potentially affecting drug clearance. Whole proteomics liver analysis confirmed the previous transcriptional results at the protein level and revealed that sex had a major influence in regulating both coagulation and drug metabolism pathways. Thus, our findings underline the need for inclusive clinical and preclinical trials to accurately reflect sex-specific metabolic variations, and to consider CKD-specific changes to optimize dosing, minimize side effects, and improve patient outcomes.

Abcb1 is involved in the efflux of trivalent inorganic arsenic from brain microvascular endothelial cells

Arsenic (As) can penetrate brain tissue through the blood-brain barrier (BBB), and the ATP-binding cassette subfamily B member 1 (Abcb1) has been shown to facilitate the transport of inorganic arsenic (iAs) in animal liver, small intestine, and yeast. However, the relationship between Abcb1 and BBB has not been reported, and the mechanism of brain microvascular endothelial cells Abcb1 on the transport of iAs needs to be further studied. Increased arsenic levels were observed in mice exposed to 25 mg/L or 50 mg/L of sodium arsenite (NaAsO2) in drinking water, and both arsenic uptake and efflux were detected in bEnd.3 cells treated with 16 μmol/L NaAsO2. Elevated levels of Abcb1 protein were found in the NaAsO2-exposed mouse brain microvascular endothelium and in NaAsO2-treated bEnd.3 cells. Inhibition of Abcb1's efflux function significantly reduced the 2-hour arsenic efflux rate in bEnd.3 cells loaded arsenic. Conversely, overexpression of either Abcb1a or Abcb1b significantly increased the 2-hour arsenic efflux rate in these cells loaded arsenic. These findings suggest that Abcb1 may play a crucial role in mediating arsenic efflux from mouse brain microvascular endothelial cells.

Integration of transcriptomics and metabolomics reveals toxicological mechanisms of ZhuRiHeng drop pill in the 180-day repeated oral toxicity study

Background: ZhuRiHeng Drop Pill (ZRH) is a traditional Mongolian medicinal preparation. Despite its long history of use for the treatment of coronary heart disease, there have been few toxicological studies of the safety profile of ZRH. Purpose: In order to comprehensively elucidate the underlying mechanisms behind the observed toxicity of ZRH on rat livers in the 180-day repeated oral toxicity study, we conducted a comprehensive analysis by integrating transcriptomic and metabolomic data. Methods: High-resolution mass spectrometry was conducted to evaluate the constituents of ZRH. For the acute oral toxicity study, mice were administered a dose of 32 g/(kg·d) of ZRH, while rats were instead orally administered 0.934, 1.868, or 3.736 g/(kg·d) of ZRH over a 180-day period in a 180-day repeated oral toxicity study. Conventional index and organ weights/histology were then monitored to detect any potential ZRH treatment-related toxicity. To identify key genes and metabolites involved in ZRH toxicological processes, we performed transcriptomic and metabolomic analyses of liver tissue upon ZRH treatment using RNA-seq techniques, qPCR and liquid chromatography-mass spectrometry analyses. Results: A total of 60 compounds in ZRH were identified and speculated in positive and negative ion modes. Mice in the acute toxicity study exhibited no signs of ZRH-related toxicity. In a protracted oral toxicity investigation spanning 180 days, discernible elevations in liver ratios were noted in both male and female rats across all three dose cohorts, relative to the control group (p < 0.05 or p < 0.01). Upon subjecting to ZRH treatment, our transcriptomic and qPCR analyses unveiled notable upregulation of crucial genes, exemplified by Abcb1b and Cyp2b2, known for theirs involvement in liver drug transport and metabolism function. Furthermore, our untargeted metabolomic analysis provided supplementary insights, revealing significant regulation in pyrimidine metabolism, as well as alanine, aspartate, and glutamate metabolism pathways. Conclusion: Our study unveils a panoramic understanding of the temporal, dosage-specific, and gene dimensions surrounding the metabolic and transcriptional shifts induced by ZRH exposure. As we peer into the future, recommendations emerge for further exploration, encompassing aspects such as time dynamics, dosage considerations, and gene-centric avenues to enhance therapeutic efficacy.

A critical role for host-derived cystathionine-β-synthase in Staphylococcus aureus-induced udder infection

Cystathionine-β-synthase (CBS) catalyzes the first step of the transsulfuration pathway. The role of host-derived CBS in Staphylococcus aureus (S. aureus)-induced udder infection remains elusive. Herein, we report that S. aureus infection enhances the expression of CBS in mammary epithelial cells in vitro and in vivo. A negative correlation is present between the expression of CBS and inflammation after employing a pharmacological inhibitor/agonist of CBS. In addition, CBS achieves a fine balance between eliciting sufficient protective innate immunity and preventing excessive damage to cells and tissues preserving the integrity of the blood-milk barrier (BMB). CBS/H2S reduces bacterial load by promoting the generation of antibacterial substances (ROS, RNS) and inhibiting apoptosis, as opposed to relying solely on intense inflammatory reactions. Conversely, H2S donor alleviate inflammation via S-sulfhydrating HuR. Finally, CBS/H2S promotes the expression of Abcb1b, which in turn strengthens the integrity of the BMB. The study described herein demonstrates the importance of CBS in regulating the mammary immune response to S. aureus. Increased CBS in udder tissue modulates excessive inflammation, which suggests a novel target for drug development in the battle against S. aureus and other infections.

Sildenafil aggravates adriamycin-induced testicular toxicity in rats; a preliminary investigation

Male reproductive toxicity is a well-established side effect of the chemotherapeutic drug adriamycin (ADR). Sildenafil (SIL) is a phosphodiesterase inhibitor known to enhance the chemosensitivity of cancer cells to ADR. However, there is a scarcity of information on the effect of SIL on ADR-induced testicular toxicity. In this study, SIL (5, 10, or 20 mg/kg/day) was administered to male rats for 7 days, followed by a single intraperitoneal injection of ADR (20 mg/kg) on day 7. Control rats received either ADR, SIL, or normal saline for 7 days. Epididymal sperm were collected from the testes to assess the effects on sperm quality, quantity, and serum testosterone concentration was also determined. ADR treatment caused a decrease in sperm motility and elevated the percentage of sperms with tail defects which worsened in combination with SIL (20 mg/kg). Furthermore, ADR alone or in combination with SIL dose-dependently increased total sperm abnormalities. SIL (20 mg/kg) plus ADR also decreased sperm count and lowered testosterone level compared to ADR-only rats. In conclusion, exposure of rats to SIL before ADR treatment has the potential to worsen ADR-induced testicular toxicity.

The ATP-binding cassette proteins ABCB1 and ABCC1 as modulators of glucocorticoid action

Responses to hormones that act through nuclear receptors are controlled by modulating hormone concentrations not only in the circulation but also within target tissues. The role of enzymes that amplify or reduce local hormone concentrations is well established for glucocorticoid and other lipophilic hormones; moreover, transmembrane transporters have proven critical in determining tissue responses to thyroid hormones. However, there has been less consideration of the role of transmembrane transport for steroid hormones. ATP-binding cassette (ABC) proteins were first shown to influence the accumulation of glucocorticoids in cells almost three decades ago, but observations over the past 10 years suggest that differential transport propensities of both exogenous and endogenous glucocorticoids by ABCB1 and ABCC1 transporters provide a mechanism whereby different tissues are preferentially sensitive to different steroids. This Review summarizes this evidence and the new insights provided for the physiology and pharmacology of glucocorticoid action, including new approaches to glucocorticoid replacement.

The role of different compounds on the integrity of blood-testis barrier: A concise review based on in vitro and in vivo studies

Sertoli cells are "nurturing cells'' in the seminiferous tubules of the testis which have essential roles in the development, proliferation and differentiation of germ cells. These cells also divide the seminiferous epithelium into a basal and an adluminal compartment and establish the blood-testis barrier (BTB). BTB shields haploid germ cells from recognition by the innate immune system. Moreover, after translocation of germ cells into the adluminal compartment their nutritional source is separated from the circulatory system being only supplied by the Sertoli cells. The integrity of BTB is influenced by several organic/ organometallic, hormonal and inflammatory substances. Moreover, several environmental contaminants such as BPA have hazardous effects on the integrity of BTB. In the current review, we summarize the results of studies that assessed the impact of these agents on the integrity of BTB. These studies have implications in understanding the molecular mechanism of male infertility and also in the male contraception.

Effects of oral exposure to arsenite on arsenic metabolism and transport in rat kidney

Nephrotoxicity is within the recognized toxic effects of arsenic. In this study we assessed the effect of arsenite on the renal capacity to metabolize and handle arsenicals in rats exposed to drinking water with 0, 1, 5, or 10 ppm sodium arsenite for ten days. Arsenite treatment did not affect the gene expression of the main enzyme catalyzing methylation of arsenite, As3mt, while it reduced the expression of GSTO1 mRNA and protein. Arsenite decreased the expression of Aqp3, Mrp1, Mrp4, and Mdr1b (i.e., transporters and channels used by arsenic), but not that of Aqp7, Glut1, Mrp2, and Mdr1a. The protein abundance of AQP3 was also reduced by arsenite. Arsenite increased urinary NGAL and FABP3 and decreased Klotho plasma levels, without alteration of creatinine, which evidenced early tubular damage. Renal Klotho mRNA and protein expressions were also downregulated, which may exacerbate renal damage. No effect was observed in selected miRNAs putatively associated with renal injury. Plasma PTH and FGF23 were similar between groups, but arsenite decreased the renal expression of Fgfr1 mRNA. In conclusion, exposure to arsenite alters the gene expression of proteins involved in the cellular handling of arsenical species and elicits tubular damage.