ATP-binding Cassette Research Articles

Effects of flavonoids on yeast ABC transporters activity

Flavonoids are known to be effective biomodulators of various processes in eukaryotic cells. As these compounds are present in wine and beer raw materials, they can influence the qualitative characteristics of the ethanol content in wine-making and brewing products, including directly through the mechanisms of regulation of gene expression and the activity of ATP-binding cassette (ABC) proteins. The main function of ABC transporters in yeast cells is to transport various substrates, including ethanol. This process ensures the survival of yeast cells under conditions of ethanol stress. It has been found that flavonoids, as well as their Schiff base derivatives, are effective stimulators and inhibitors of mRNA expression and activity of ABC proteins both in logarithmic and stationary phases of growth, which has a direct impact on bioethanol production by yeast.

Transcriptome and Metabolome Analysis of BmFAMeT6 Overexpression in Bombyx mori.

Background/Objectives: The gene-encoding farnesyl diphosphate O-methyltransferase 6 (FAMeT 6) is a member of the farnesyl diphosphate O-methyltransferase family. Our previous studies have demonstrated its influence on juvenile hormone levels in third instar silkworm larvae. Methods: we utilized transcriptomic and metabolomic techniques to investigate the changes in third instar larvae at 0, 12, and 24 h following BmFAMeT6 overexpression. Results: (1) The differentially expressed homologous genes were enriched in detoxification-related pathways at all three time points. (2) Transcription factor analysis of DEGs indicated a predominant presence of ZF-C2H2. (3) The metabolite-related network suggested that BmFAMeT6 may influence the metabolism of silkworm larvae through the ABC transporters, purine metabolism, and tyrosine metabolism pathways. (4) The differential gene count, differential metabolite count, and types of metabolites at the three time points indicated a shift in the regulatory focus within the larvae as time progresses, with the inflection point of regulation occurring at the third instar larval stage, 12 h. Conclusion: In summary, our research indicates that the regulatory role of BmFAMeT6 occurs within the context of the domestic silkworm's own growth and development regulation.

Expanding the spectrum of progressive familial intrahepatic cholestasis: A report of 3 cases.

Progressive familial intrahepatic cholestasis (PFIC) is a group of autosomal recessive disorders caused by defects in bile secretion or transport usually presenting as cholestasis in pediatric age. Herewith, we describe 3 PFIC cases with diagnostic challenges and highlight the role of genetic analysis. The clinical history, laboratory data, liver biopsy, and molecular analysis for each case were reviewed. Case 1, a Hispanic male from Puerto Rico with hepatomegaly since age 2 months, was eventually diagnosed with PFIC3 following identification of a homozygous splice site variant in ATP binding cassette subfamily B member 4 (ABCB4) (c.2784-12T>C) at age 17 years by whole-exome sequencing (WES). Case 2 was a 37-year-old man with a history of alcoholism, abnormal liver function tests, and ductopenia on biopsy. Molecular testing revealed a pathogenic heterozygous ABCB4 mutation (c.1633C>T) variant leading to a diagnosis of PFIC3. Case 3 was a 2-year-old female initially presenting as a drug-induced liver injury but was diagnosed with PFIC10 following identification of a heterozygous frameshift mutation (p.Asp300Trpfs*19) and a heterozygous missense mutation (c.1357T>C) in myosin VB (MYO5B) by WES. These PFIC cases highlight the heterogenous presentation and diagnostic challenges, and they emphasize the role of next-generation sequencing, particularly the utility of WES.

Characterization of ATP-binding cassette transporters associated with emamectin benzoate tolerance: from the model insect Drosophila melanogaster to the agricultural pest Spodoptera frugiperda.

Multiple families of detoxification genes, including the increasingly recognized family of ATP-binding cassette (ABC) transporters, work together to influence the toxicity of synthetic insecticides and thus their resistance. Effective management of insecticide resistance requires identification of all toxicity-affecting members from each family of toxicity-related genes. Here, we used emamectin benzoate (EB), ABC transporters and Spodoptera frugiperda as a working case to test whether the strategy of 'from the model insect Drosophila melanogaster to agricultural pests' can identify all or most ABC transporter members related to EB tolerance in S. frugiperda. After confirming the involvement of ABC transporters in the toxicity of EB against fruit fly with the ABC inhibitor verapamil, four ABC transporter genes (DmCG3327, DmCG11147, DmCG4822, and DmCG7627) were found to be involved in EB tolerance using RNA interference-based family-wide functional screening. A combination of phylogenic analysis and a reciprocal TBLASTN search identified five S. frugiperda ABC transporter members as homologs (SfABCC4, SfABCG1, and SfABCG23) or one-way best hits (SfABCG4 and SfABCG20) of the four fly ABC genes. Real-time quantitative polymerase chain reaction (qPCR) analysis found that all five S. frugiperda ABC transporter genes were inducible by EB, and expressed in all the developmental stages and larval tissues, but with significant quantitative differences among stages and tissues. A cytotoxicity assay of ABC-overexpressing Sf9 cell lines showed that all the five S. frugiperda ABC transporter genes made Sf9 cells tolerant to EB. This study not only identifies nine ABC transporter genes related to EB tolerance from D. melanogaster (four genes) and S. frugiperda (five genes), but also demonstrates the utility and effectiveness of the 'model to pests' strategy to identify most toxicity-affecting members from a given family of toxicity-related genes. © 2024 Society of Chemical Industry.

Two Half-Size ATP-Binding Cassette Transporters Are Implicated in Aluminum Tolerance in Soybean.

Aluminum (Al) toxicity severely restricts plant production in acidic soils. ATP-binding cassette (ABC) transporters participate in plant tolerance to various environmental stresses. However, ABC transporters implicated in soybean Al tolerance are still rare. Here, we functionally characterized two half-size ABC transporters (GmABCB48 and GmABCB52) in soybean. Expression analysis showed that GmABCB48 and GmABCB52 were induced only in the roots, especially in the root tips. Both GmABCB48 and GmABCB52 were localized at the plasma membrane. Overexpression of GmABCB48 or GmABCB52 in Arabidopsis reduced Al accumulation in roots and enhanced Al tolerance. However, expression of GmABCB48 or GmABCB52 in yeast cells did not affect Al uptake. Furthermore, transgenic lines expressing GmABCB48 or GmABCB52 had lower Al content in root cell walls than wild-type plants under Al stress. Further investigation showed that the Al content in cell wall fractions (pectin and hemicellulose 1) of transgenic lines was significantly lower than that of wild-type plants, which was coincident with the changes of pectin and hemicellulose 1 content under Al exposure. These results indicate that GmABCB48 and GmABCB52 confer Al tolerance by regulating the cell wall polysaccharides metabolism to reduce Al accumulation in roots.

Toxicity mechanism of organosilicon adjuvant in combination with S-metolachlor on Vigna angularis

The widespread use of S-metolachlor (ME) in agriculture to suppress weeds and boost crop yields, particularly in cultivating Vigna angularis, is well established. However, the application of organosilicon adjuvants with herbicides has potential threats to non-target crops. This study investigates the toxicity symptoms and mechanisms when V. angularis is exposed to ME in conjunction with a common organosilicon adjuvant. Results indicate that ME inhibits the growth of V. angularis seedlings, and adding adjuvants could aggravate the negative effects of ME. According to the growth index of seedlings, the adjuvant increased the toxicity of ME by 84–96 %. Additionally, the chlorophyll content, root permeability, and antioxidant indicators in the seedlings were also adversely affected. Integrated metabolomics and transcriptomics analyses reveal that differentially abundant metabolites (DAMs) and differentially expressed genes (DEGs) are mainly enriched in four ways: "lysine degradation," "ABC transporters," "phenylalanine metabolism," and "monoterpenoid biosynthesis." The metabolic pathways and gene regulatory network involving 11 DAMs and 22 DEGs are associated with the physiological processes affected by ME and the adjuvant. This study provides guidance for the application of herbicides and their adjuvants in agricultural production to minimize adverse effects on non-target crops.

Membrane-Targeting Amphiphilic Honokiol Derivatives Containing an Oxazole Moiety as Potential Antibacterials against Methicillin-Resistant Staphylococcus aureus.

Infections with methicillin-resistant Staphylococcus aureus (MRSA) are becoming increasingly serious, making the development of novel antimicrobials urgent. Here, we synthesized some amphiphilic honokiol derivatives bearing an oxazole moiety and investigated their antibacterial and hemolytic activities. Bioactivity evaluation showed that E17 possessed significant in vitro antibacterial activity against S. aureus and MRSA, along with low hemolytic activity. Moreover, E17 exhibited rapid bactericidal properties and was not susceptible to resistance. Mechanistic studies indicated that E17 interacts with phosphatidylglycerol and cardiolipin of bacterial cell membranes, leading to changes in cell membrane permeability and polarization, increased intracellular ROS, and leakage of DNA and proteins, thus accelerating bacterial death. Transcriptome analysis further demonstrated that E17 has membrane-targeting effects, affecting the expression of genes related to cell membranes and ABC transporter proteins. Notably, in vivo activity showed that E17 has prominent anti-MRSA efficacy, comparable to vancomycin, and is expected to be a new anti-MRSA drug candidate.

Identification of NanoLuciferase Substrates Transported by Human ABCB1 and ABCG2 and their Zebrafish Homologs at the Blood-Brain Barrier.

ATP-binding cassette (ABC) transporters expressed at the blood-brain barrier (BBB) impede delivery of therapeutic agents to the brain, including agents to treat neurodegenerative diseases and primary and metastatic brain cancers. Two transporters, P-glycoprotein (P-gp, ABCB1) and ABCG2, are highly expressed at the BBB and are responsible for the efflux of numerous clinically useful chemotherapeutic agents, including irinotecan, paclitaxel, and doxorubicin. Based on a previous mouse model, we have generated transgenic zebrafish where expression of NanoLuciferase (NanoLuc) is controlled by the promoter of glial fibrillary acidic protein, leading to expression in zebrafish glia. To identify agents that disrupt the BBB including inhibitors of ABCB1 and ABCG2, we identified NanoLuc substrates that are also transported by P-gp, ABCG2, and their zebrafish homologs. These substrates will elevate the amount of bioluminescent light produced in the transgenic zebrafish with BBB disrpution. We transfected HEK-293 cells with both NanoLuc and human ABCB1 or ABCG2, or their zebrafish homologs Abcb4 and Abcg2a, which are functionally homologous to human P-gp and ABCG2, respectively, and expressed at the zebrafish BBB. We evaluated the brightness of ten NanoLuc substrates, then screened the eight brightest for their ability to be effluxed by the ABC transporters. We identified one ABCB1 substrate, two Abcb4 substrates, six ABCG2 substrates, and four Abcg2a substrates. These data will aid in the development of a transgenic zebrafish model of the BBB to identify novel BBB disruptors and should prove useful in the development of other animal models that use NanoLuc as a reporter. Significance Statement The ATP-Binding Cassette (ABC) transporters ABCB1 and ABCG2 at the blood-brain barrier (BBB) hinder pharmacological treatment of brain-related diseases. Consequently, there is a need for tools to identify BBB disruptors. We conducted a screen of ten NanoLuciferase substrates, identifying the brightest and those that were transported by human and zebrafish ABC transporters at the BBB. This work supports and complements our development of a transgenic zebrafish model, in which NanoLuciferase is expressed within glial cells, enabling detection of BBB disruption.

Genetic analysis of the X-linked Adrenoleukodystrophy ABCD1 gene in Drosophila uncovers a role in Peroxisomal dynamics.

X-linked adrenoleukodystrophy (X-ALD) is a progressive neurodegenerative disorder caused by a loss-of-function (LOF) mutation in the ATP-binding cassette subfamily D member 1 (ABCD1) gene, leading to the accumulation of very long-chain fatty acids (VLCFAs). This disorder exhibits striking heterogeneity; some male patients develop an early childhood neuroinflammatory demyelination disorder, while other patients, including adult males and most affected female carriers, experience a chronic progressive myelopathy. Adrenocortical failure is observed in almost all male patients, with age of onset varying sometimes being the first diagnostic finding. The gene underlying this spectrum of disease encodes an ATP-binding cassette (ABC) transporter that localizes to peroxisomes and facilitates VLCFA transport. X-ALD is considered a single peroxisomal component defect and does not play a direct role in peroxisome assembly. Drosophila models of other peroxisomal genes have provided mechanistic insight into some of the neurodegenerative mechanisms with reduced lifespan, retinal degeneration, and VLCFA accumulation. Here, we perform a genetic analysis of the fly ABCD1 ortholog Abcd1 (CG2316). Knockdown or deficiency of Abcd1 leads to VLCFA accumulation, salivary gland defects, locomotor impairment and retinal lipid abnormalities. Interestingly, there is also evidence of reduced peroxisomal numbers. Flies overexpressing the human cDNA for ABCD1 display a wing crumpling phenotype characteristic of the pex2 loss-of-function. Surprisingly, overexpression of human ABCD1 appears to inhibit or overwhelm peroxisomal biogenesis to levels similar to null mutations in fly pex2, pex16 and pex3. Drosophila Abcd1 is therefore implicated in peroxisomal number, and overexpression of the human ABCD1 gene acts a potent inhibitor of peroxisomal biogenesis in flies.

Betaine Induces Apoptosis and Inhibits Invasion in OSCC Cell Lines.

Betaine, known as trimethylglycine, is a non-toxic natural substance reported to affect cancer cell responses. This study delves into the impact of betaine on the survival, proliferation, and invasion of oral squamous cell carcinoma (OSCC) cells in vitro. Human OSCC cells (HSC-4 and HSC-7) were subjected to varying concentrations of betaine, and their viability and proliferation were assessed through colourimetric MTT and colony-forming unit assays. Cell cycle progression and cell apoptosis were also investigated using flow cytometry, while cell migration and invasion were examined using a transwell migration assay, and the mRNA expression was evaluated by a quantitative polymerase chain reaction. Finally, proteomic analysis was conducted through liquid chromatography-tandem mass spectrometry on the extracted protein component of the cells. Results indicate that betaine effectively suppressed OSCC proliferation and colony formation. It triggered early apoptosis without disrupting cell cycle progression, reduced cell migration, and inhibited invasion. Betaine exposure led to significantly decreased mRNA levels of MMP1, MMP2, and MMP9 while downregulating FN1, a gene linked to epithelial-to-mesenchymal transition. Proteomic analysis revealed 9240 differentially expressed up/downregulated proteins in cells treated with betaine. The significantly upregulated proteins were associated with ATP-binding cassette (ABC) transporters, while the down-regulated proteins were associated with G protein-coupled receptors (GPCR) ligand binding. In conclusion, betaine exhibits potent anti-cancer properties by attenuating OSCC cell proliferation and mitigating invasion. Exploring this natural product as an adjunct for managing oral squamous cell carcinoma shows promise, although further investigations are needed to fully elucidate its functionality.

Human trophoblast organoids for improved prediction of placental ABC transporter-mediated drug transport

ATP-binding cassette (ABC) transporters, the important transmembrane efflux transporters, play an irreplaceable role in the placenta barrier. The disposition and drug-drug interaction of clinical drugs are also closely related to the functions of ABC transporters. The trophoblast is a unique feature of the placenta, which is crucial for normal placentation and maintenance during pregnancy. ABC transporters are abundantly expressed in placental syncytiotrophoblast, especially P-gp, BCRP, and MRPs. However, due to the lack of appropriate modeling systems, the molecular mechanisms of regulation between ABC transporters and trophoblast remains unclear. In this report, trophoblast organoids were cultured from human placental villi and developed into three-dimension structures with cavities. Trophoblast organoids exhibited transporter expression and localization comparable to that in villous tissue, indicating their physiological relevance for modeling drug transport. Moreover, fluorescent substrates can accumulate in organoids and be selectively inhibited by inhibitors, indicating the efflux function of ABC transporters (P-gp, BCRP, MRP1, and MRP2) in organoids. Two commonly used hypertension drugs and three antipsychotics were chosen to further validate this drug transport model and demonstrate varying degrees of inhibitory effects on ABC transporters. Overall, a new drug transport model mediated by ABC transporter has been successfully established based on human trophoblast organoids, which can be used to study drug transport in the placenta.

Comparative Study on Growth and Metabolomic Profiles of Six Lactobacilli Strains by Sodium Selenite

Selenium (Se) has garnered increasing attention in the field of nutrition, as it is essential for both humans and animals. Certain microorganisms can enrich inorganic selenium and convert it into organic selenium. The growth and metabolomic profiles of six lactobacilli strains exposed to 50 μg/mL of sodium selenite were performed using gas chromatography tandem time-off light mass spectrometry (GC-TOF-MS) analysis. The addition of selenium significantly increased both the population and weight of the Lacticaseibacillus rhamnosus PS5, Lbs. rhamnosus RT-B, Limosilactobacillus reuteri 3630, and Lmb. reuteri 1663 strains, while those of the other two strains decreased. A total of 271 metabolites were determined, with their concentrations ranked from highest to lowest as follows: organic acids and derivatives, oxygen compounds, lipids and lipid-like molecules, and benzenoids. In certain groups, the concentrations of serine, aspartic acid, trehalose, palmitic acid, methylthreonine, and melibiose increased significantly, whereas glucuronic acid, ribose, ornithine, and methionine were downregulated. The metabolic pathways were significantly associated with ABC transporters, glycine, serine, threonine metabolism, and aminobenzoate degradation and other pathways. Based on these findings, we concluded that the transport, absorption, assimilation, and stress response to selenium by lactobacilli in metabolomic changed. Furthermore, the metabolomic alterations among different types of lactobacilli varied primarily due to their distinct properties.

KaiXinSan improves learning and memory impairment by regulating cholesterol homeostasis in mice overloaded with 27-OHC

Cholesterol and its oxidative products—oxysterols homeostasis— play a crucial role in maintaining cognitive function. Chinese medicine KaiXinSan (KXS) has demonstrated effectiveness in treating mental illness and regulating cognitive dysfunction of Alzheimer's disease (AD). The purpose of this article is to explore whether the KXS can enhance cognitive function by regulating cholesterol homeostasis. Employing the 27-hydroxy cholesterol (27-OHC) induced mice model of cognitive dysfunction and coculture model of assessment neurocyte damage, we investigated learning and memory abilities while concurrently addressing the reduction of neuronal cell damage through the regulation of cholesterol metabolism. 21 days of KXS treatment improved the learning and memory ability in mice 27-OHC-overloading by alleviating the exacerbated deposition of amyloid-β (Aβ), reducing inflammatory reactions, and mitigating synaptic plasticity damage. Additionally, it repaired myelin sheath function. More importantly, KXS significantly affects the metabolism of central cholesterol by substantially inhibiting the expression of liver X receptor (LXR), ATP-binding cassette transporter (ABCA1, ABCG1), apolipoprotein E (ApoE) and upregulated cytochrome P450 46A1(CYP46A1). Furthermore, KXS may alleviate 27-OHC-induced neuronal inflammation and apoptosis by promoting the conversion of cholesterol to 24-hydroxycholesterol (24-OHC) via CYP46A1 and suppressing cholesterol release from astrocyte cells. Altogether, our results demonstrate that KXS can prevent learning and memory impairments induced by 27-OHC loading. This effect may be related to its multitarget capability in promoting the conversion of excessive cholesterol to 24-OHC and maintaining a balance in cholesterol homeostasis and metabolism between neurons and astrocyte cells.

The Systemic Effect of Ischemia Training and Its Impact on Bone Marrow-Derived Monocytes.

Monocytes are innate immune cells that play a central role in inflammation, an essential component during neovascularization. Our recent publication demonstrated that ischemia training by 24 h unilateral occlusion of the femoral artery (FA) can modify bone marrow-derived monocytes (BM-Mono), allowing them to improve collateral remodeling in a mouse model of hindlimb ischemia. Here, we expand on our previous findings, investigating a potential systemic effect of ischemia training and how this training can impact BM-Mono. BM-Mono from mice exposed to ischemia training (24 h) or Sham (same surgical procedure without femoral artery occlusion-ischemia training) procedures were used as donors in adoptive transfer experiments where recipients were subjected to hindlimb ischemia. Donor cells were divided corresponding to the limb from which they were isolated (left-limb previously subjected to 24 h ischemia and right-contralateral limb). Recipients who received 24 h ischemic-trained monocytes isolated from either limb had remarkable blood flow recovery compared to recipients with Sham monocytes (monocytes isolated from Sham group-no ischemia training). Since these data suggested a systemic effect of ischemic training, circulating extracellular vesicles (EVs) were investigated as potential players. EVs were isolated from both groups, 24 h-trained and Sham, and the former showed increased expression of histone deacetylase 1 (HDAC1), which is known to downregulate 24-dehydrocholesterol reductase (Dhcr24) gene expression. Since we previously revealed that ischemia training downregulates Dhcr24 in BM-Mono, we incubated EVs from 24 h-trained and Sham groups with wild-type (WT) BM-Mono and demonstrated that WT BM-Mono incubated with 24 h-trained EVs had lower gene expression of Dhcr24 and an HDAC1 inhibitor blunted this effect. Next, we repeated the adoptive transfer experiment using Dhcr24 KO mice as donors of BM-Mono for WT mice subjected to hindlimb ischemia. Recipients who received Dhcr24 KO BM-Mono had greater limb perfusion than those who received WT BM-Mono. Further, we focused on the 24 h-trained monocytes (which previously showed downregulation of Dhcr24 gene expression and higher desmosterol) to test the expression of a few genes downstream of the desmosterol pathway, confirm the Dhcr24 protein level and assess its differentiation in M2-like macrophage phenotype. We found that 24 h-trained BM-Mono had greater expression of key genes in the desmosterol pathway, such as liver X receptors (LXRs) and ATP-binding cassette transporter (ABCA1), and we confirmed low protein expression of Dhcr24. Further, we demonstrated that ischemic-trained BM-Mono polarized towards an anti-inflammatory M2 macrophage phenotype. Finally, we demonstrated that 24 h-trained monocytes adhere less to endothelial cells, and the same pattern was shown by WT BM-Mono treated with Dhcr24 inhibitor. Ischemia training leads to a systemic effect that, at least in part, involves circulating EVs and potential epigenetic modification in BM-Mono. These ischemic-trained BM-Mono demonstrated an anti-inflammatory phenotype towards M2 macrophage differentiation and less ability to adhere to endothelial cells, which is associated with the downregulation of Dhcr24 in those cells. These data together suggest that Dhcr24 might be an important target within monocytes to improve the outcomes of hindlimb ischemia.

An in vitro set-up to study Pdr5-mediated substrate translocation.

Pdr5 is the most abundant ABC transporter in Saccharomyces cerevisiae and plays a major role in the pleiotropic drug resistance (PDR) network, which actively prevents cell entry of a large number of structurally unrelated compounds. Due to a high level of asymmetry in one of its nucleotide binding sites (NBS), Pdr5 serves as a perfect model system for asymmetric ABC transporter such as its medical relevant homologue Cdr1 from Candida albicans. In the past 30 years, this ABC transporter was intensively studied in vivo and in plasma membrane vesicles. Nevertheless, these studies were limited since it was not possible to isolate and reconstitute Pdr5 in a synthetic membrane system while maintaining its activity. Here, the functional reconstitution of Pdr5 in a native-like environment in an almost unidirectional inside-out orientation is described. We demonstrate that reconstituted Pdr5 is capable of translocating short-chain fluorescent NBD lipids from the outer to the inner leaflet of the proteoliposomes. Moreover, this transporter revealed its ability to utilize other nucleotides to accomplish transport of substrates in a reconstituted system. Besides, we were also able to estimate the NTPase activity of reconstituted Pdr5 and determine the kinetic parameters for ATP, GTP, CTP, and UTP.

Differential Selectivity of Human and Mouse ABCC4/Abcc4 for Arsenic Metabolites.

Millions of people globally are exposed to the proven human carcinogen arsenic at unacceptable levels in drinking water. In contrast, arsenic is a poor rodent carcinogen, requiring >100-fold higher doses for tumour induction, which may be explained by toxicokinetic differences between humans and mice. The human ATP-binding cassette (ABC) transporter hABCC4 mediates the cellular efflux of a diverse array of metabolites, including the GSH conjugate of the highly toxic monomethylarsonous acid (MMAIII), MMA(GS)2, and the major human urinary arsenic metabolite dimethylarsinic acid (DMAV). Our objective was to determine if mouse Abcc4 (mAbcc4) protected against and/or transported the same arsenic species as hABCC4. The anti-ABCC4 antibody M4I-10 epitope was first mapped to an octapeptide (411HVQDFTA418F) present in both hABCC4 and mAbcc4, enabling quantification of relative amounts of hABCC4/mAbcc4. mAbcc4 expressed in HEK293 cells did not protect against any of the six arsenic species tested [arsenite, arsenate, MMAIII, monomethylarsonic acid, dimethylarsinous acid or DMAV], despite displaying remarkable resistance against the antimetabolite 6-mercaptopurine (>9-fold higher than hABCC4). Furthermore, mAbcc4-enriched membrane vesicles prepared from transfected HEK293 cells did not transport MMA(GS)2 or DMAV, despite a >3-fold higher transport activity than hABCC4-enriched vesicles for the prototypic substrate 17β-estradiol-17-(β-D-glucuronide). Abcc4(+/+) mouse embryonic fibroblasts (MEFs) were ~3-fold more resistant to arsenate than Abcc4(-/-) MEFs; however, further characterization indicated this was not mAbcc4 mediated. Thus, under the conditions tested, arsenicals are not transported by mAbcc4, and differences between the substrate selectivity of hABCC4 and mAbcc4 seem likely to contribute to differences in human and mouse arsenic toxicokinetics. Significance Statement Toxicokinetics of the carcinogen arsenic differ among animal species. Arsenic methylation is known to contribute to this, whereas arsenic transporters have not been considered. The human ATP-binding cassette transporter hABCC4 is a high affinity transporter of toxicologically important arsenic metabolites. Here we used multiple cell models to demonstrate that mouse Abcc4 does not protect cells against, or transport, any arsenic species tested. Thus, differences between hABCC4 and mAbcc4 substrate selectivity likely contribute to differences in human and mouse arsenic toxicokinetics.

Aged garlic oligosaccharides modulate host metabolism and gut microbiota to alleviate high-fat and high-cholesterol diet-induced atherosclerosis in ApoE−/− mice

Atherosclerosis (AS) is a cardiovascular disease caused by excessive accumulation of lipids in arterial walls. In this study, we developed an AS model in ApoE−/− mice using a high-fat, high-cholesterol diet and investigated the anti-AS mechanism of aged garlic oligosaccharides (AGOs) by focusing on the gut microbiota. Results revealed that AGOs exhibited significant anti-AS effects, reduced trimethylamine N-oxide levels from 349.9 to 189.2 ng/mL, and reduced aortic lipid deposition from 31.7 % to 9.5 %. AGOs significantly increased the levels of short-chain fatty acids in feces, in which acetic, propionic, and butyric acids were increased from 1.580, 0.364, and 0.469 mg/g to 2.233, 0.774, and 0.881 mg/g, respectively. An analysis of the gut microbiota indicated that AGOs restored alpha and beta diversity, decreased the Firmicutes/Bacteroidetes ratio, and promoted the dominance of the genus Akkermansia. A metagenomic analysis revealed that AGOs alleviated AS through the ABC transporter pathway and the lipopolysaccharide biosynthesis pathway.

Abstract C050: Breast cancer in Ghana: assessment of multidrug-resistant genes among breast cancer patients

Abstract Breast cancer (BC) is the most frequently diagnosed cancer among women globally and chemotherapy plays a crucial role in its management in sub-Saharan Africa. The long-term BC survival rate remains poor due to chemoresistance. Over 80% of currently used chemotherapy drugs are substrates of ABC transporter genes, ABCB1, ABCC1 and ABCG2. Possessing the wild-type genotype and alleles of these genes reduces intracellular drug accumulation and leads to poorer treatment outcomes due to the upregulation of efflux function. This study therefore determined the allelic and genotype frequencies of three variant alleles, rs1045642, rs28706727 and rs2231142 in these transporter genes, and assessed the association between the variant statuses and BC recurrence or metastasis in the Ghanaian BC population. A quantitative, observational, case-control study was conducted using a purposive and convenience sampling method. Sociodemographic and clinical data were collected from study participants using questionnaires and a review of medical records. Extracted blood DNA from participants was used to determine the gene variants in ABCB1, ABCC1 and ABCG2 genes using the TaqMan Allelic Discrimination assays. A significantly high frequency (p ≤ 0.001) of the homozygous wild-type genotypes and alleles (ABCB1 had 77.3%/88% for CC/C, ABCC1 had 95.3%/97.7% for GG/G and ABCG2 had 100%/100% for CC/C) was found in both case and control groups. The wild-type genotypes and alleles of ABCB1, ABCC1 and ABCG2 may contribute to poor BC treatment outcomes among Ghanaian BC patients receiving chemotherapy. Citation Format: Gloria Agyekum Boaitey, Rachel Martini, Nourddine Dean Djeddar, Brian Stonaker, Stevens M. Patino, Jason White, Ernest Osei Bonsu, Yaw Agyekum Boaitey, Christian Obirikorang, Melissa B. Davis, Linda Ahenkorah Fondjo. Breast cancer in Ghana: assessment of multidrug-resistant genes among breast cancer patients [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C050.

MAPK signaling pathway enhances tolerance of Mytilus galloprovincialis to co-exposure of sulfamethoxazole and polyethylene microplastics

Microplastics (MPs) and antibiotics often coexist in complex marine environments, yet their combined detrimental effects on marine organisms remain underexplored. This study evaluated the effects of polyethylene microplastics (PE, 200 μg/L) and sulfamethoxazole (SMX, 50 μg/L), both individually and in combination, on Mytilus galloprovincialis. The exposure lasted 6 days, followed by a 6-day recovery period. Bioaccumulation, DNA damage, pollutants transport/metabolism related responses and responding alterations of mitogen-activated protein kinase (MAPK) signaling pathway were detected in gills and digestive glands. Bioaccumulation of SMX/PE in mussels occurred in a tissue-specific manner, co-exposure altered SMX contents in investigated tissues. Co-exposure did not induce extra DNA damage, elevated DNA damage was alleviated during the recovery period in all treated groups. The exposure of SMX/PE exerted different alterations in pollutants transport/metabolism related responses, characterized by multixenobiotic resistance and relative expression of key genes (cytochrome P450 monooxygenase, glutathione S-transferase, ATP-binding cassette transporters). Key molecules (p38 MAPK, c-jun N-terminal kinase, extracellular regulated protein kinase, nuclear factor-κB and tumor protein p53) in MAPK signaling pathway were activated at transcriptional and translational levels after SMX/PE and co-exposure. Co-regulation between MAPK members and pollutants transport/metabolism related factors was revealed, suggesting MAPK signaling pathway served as a regulating hub in exposed mussels to conquer SMX/PE stress. Overall, this study provides new insights on SMX/PE induced health risks in marine mussels and potential mechanism through MAPK cascades regulation.

Lignin-derived compounds assisted with Kocuria marina H-2 and Pseudomonas putida B6-2 co-culture enhanced naphthalene biodegradation

The implementation of environmentally friendly and sustainable remediation strategies positively impacts solid waste management. In this study, the Kocuria marina H-2 and Pseudomonas putida B6-2 co-culture system demonstrated enhanced naphthalene biodegradation efficiency compared to single-strain cultures. Under optimal conditions of 35 °C, 200 rpm/min, and a 1:1 ratio of the co-culture system, the naphthalene biodegradation potential was further increased. Notably, the addition of both ethylenediamine-pretreated lignin and p-hydroxybenzoic acid significantly elevated naphthalene degradation rates to 68.5 %. In addition, the oil-liquid surface tension decreased, while cell surface hydrophobicity and colony-forming units increased with the addition of lignin-derived compounds. The modification of naphthalene bioavailability by ethylenediamine-pretreated lignin would accelerate the uptake and transport of hydrocarbons via ABC transporters and flagellar assembly. Importantly, genes related to bacterial chemotaxis and fatty acid biosynthesis were upregulated during the co-metabolism of naphthalene and p-hydroxybenzoic acid, further enhancing naphthalene bioconversion.