Role of ABC transporters in lipid transport and human disease

lncRNAs: New players of cancer drug resistance via targeting ABC transporters

Cancer drug resistance poses a significant obstacle to successful chemotherapy, primarily driven by the activity of ATP-binding cassette (ABC) transporters, which actively efflux chemotherapeutic agents from cancer cells, reducing their intracellular concentrations and therapeutic efficacy. Recent studies have highlighted the pivotal role of long noncoding RNAs (lncRNAs) in regulating this resistance, positioning them as crucial modulators of ABC transporter function. lncRNAs, once considered transcriptional noise, are now recognized for their complex regulatory capabilities at various cellular levels, including chromatin modification, transcription, and post-transcriptional processing. This review synthesizes current research demonstrating how lncRNAs influence cancer drug resistance by modulating the expression and activity of ABC transporters. lncRNAs can act as molecular sponges, sequestering microRNAs that would otherwise downregulate ABC transporter genes. Additionally, they can alter the epigenetic landscape of these genes, affecting their transcriptional activity. Mechanistic insights reveal that lncRNAs contribute to the activity of ABC transporters, thereby altering the efflux of chemotherapeutic drugs and promoting drug resistance. Understanding these interactions provides a new perspective on the molecular basis of chemoresistance, emphasizing the regulatory network of lncRNAs and ABC transporters. This knowledge not only deepens our understanding of the biological mechanisms underlying drug resistance but also suggests novel therapeutic strategies. In conclusion, the intricate interplay between lncRNAs and ABC transporters is crucial for developing innovative solutions to combat cancer drug resistance, underscoring the importance of continued research in this field.

MiRNA-seq and mRNA-seq revealed the mechanism of fluoride-induced cauda epididymal injury

The widespread presence of fluoride in water, food, and the environment continues to exacerbate the impact of fluoride on the male reproductive health. However, as a critical component of the male reproductive system, the intrinsic mechanism of fluoride-induced cauda epididymis damage and the role of miRNAs in this process are still unclear. This study established a mouse fluorosis model and employed miRNA and mRNA sequencing; Evans blue staining, Oil Red O staining, TEM, immunofluorescence, western blotting, and other technologies to investigate the mechanism of miRNA in fluoride-induced cauda epididymal damage. The results showed that fluoride exposure increased the fluoride concentration in the hard tissue and cauda epididymis, altered the morphology and ultrastructure of the cauda epididymis, and reduced the motility rate, normal morphology rate, and hypo-osmotic swelling index of the sperm in the cauda epididymis. Furthermore, sequencing results revealed that fluoride exposure resulted in differential expression of 17 miRNAs and 4725 mRNAs, which were primarily enriched in the biological processes of tight junctions, inflammatory response, and lipid metabolism, with miR-742-3p, miR-141-5p, miR-878-3p, and miR-143-5p serving as key regulators. Further verification found that fluoride damaged tight junctions, raised oxidative stress, induced an inflammatory response, increased lipid synthesis, and reduced lipid decomposition and transport in the cauda epididymis. This study provided a theoretical basis for developing miRNA as potential diagnostic markers and therapeutic target drugs for this injury.

Unveiling the Influence of Copy Number Variations on Genetic Diversity and Adaptive Evolution in China's Native Pig Breeds via Whole-Genome Resequencing

Copy number variations (CNVs) critically influence individual genetic diversity and phenotypic traits. In this study, we employed whole-genome resequencing technology to conduct an in-depth analysis of 50 pigs from five local swine populations [Rongchang pig (RC), Wuzhishan pig (WZS), Tibetan pig (T), Yorkshire (YL) and Landrace (LR)], aiming to assess their genetic potential and explore their prospects in the field of animal model applications. We identified a total of 96,466 CNVs, which were subsequently integrated into 7112 non-redundant CNVRs, encompassing 1.3% of the swine genome. Functional enrichment analysis of the genes within these CNVRs revealed significant associations with sensory perception, energy metabolism, and neural-related pathways. Further selective scan analyses of the local pig breeds RC, T, WZS, along with YL and LR, uncovered that for the RC variety, the genes PLA2G10 and ABCA8 were found to be closely related to fat metabolism and cardiovascular health. In the T breed, the genes NCF2 and CSGALNACT1 were associated with immune response and connective tissue characteristics. As for the WZS breed, the genes PLIN4 and CPB2 were primarily linked to fat storage and anti-inflammatory responses. In summary, this research underscores the pivotal role of CNVs in fostering the diversity and adaptive evolution of pig breeds while also offering valuable insights for further exploration of the advantageous genetic traits inherent to China's local pig breeds. This facilitates the creation of experimental animal models tailored to the specific characteristics of these breeds, contributing to the advancement of livestock and biomedical research.

Palmitic acid induces lipid droplet accumulation and senescence in nucleus pulposus cells via ER-stress pathway

Intervertebral disc degeneration (IDD) is a highly prevalent musculoskeletal disorder affecting millions of adults worldwide, but a poor understanding of its pathogenesis has limited the effectiveness of therapy. In the current study, we integrated untargeted LC/MS metabolomics and magnetic resonance spectroscopy data to investigate metabolic profile alterations during IDD. Combined with validation via a large-cohort analysis, we found excessive lipid droplet accumulation in the nucleus pulposus cells of advanced-stage IDD samples. We also found abnormal palmitic acid (PA) accumulation in IDD nucleus pulposus cells, and PA exposure resulted in lipid droplet accumulation and cell senescence in an endoplasmic reticulum stress-dependent manner. Complementary transcriptome and proteome profiles enabled us to identify solute carrier transporter (SLC) 43A3 involvement in the regulation of the intracellular PA level. SLC43A3 was expressed at low levels and negatively correlated with intracellular lipid content in IDD nucleus pulposus cells. Overexpression of SLC43A3 significantly alleviated PA-induced endoplasmic reticulum stress, lipid droplet accumulation and cell senescence by inhibiting PA uptake. This work provides novel integration analysis-based insight into the metabolic profile alterations in IDD and further reveals new therapeutic targets for IDD treatment.

Deciphering the functional role of clinical mutations in ABCB1, ABCC1, and ABCG2 ABC transporters in endometrial cancer

ATP-binding cassette transporters represent a superfamily of dynamic membrane-based proteins with diverse yet common functions such as use of ATP hydrolysis to efflux substrates across cellular membranes. Three major transporters-P-glycoprotein (P-gp or ABCB1), multidrug resistance protein 1 (MRP1 or ABCC1), and breast cancer resistance protein (BCRP or ABCG2) are notoriously involved in therapy resistance in cancer patients. Despite exhaustive individual characterizations of each of these transporters, there is a lack of understanding in terms of the functional role of mutations in substrate binding and efflux, leading to drug resistance. We analyzed clinical variations reported in endometrial cancers for these transporters. For ABCB1, the majority of key mutations were present in the membrane-facing region, followed by the drug transport channel and ATP-binding regions. Similarly, for ABCG2, the majority of key mutations were located in the membrane-facing region, followed by the ATP-binding region and drug transport channel, thus highlighting the importance of membrane-mediated drug recruitment and efflux in ABCB1 and ABCG2. On the other hand, for ABCC1, the majority of key mutations were present in the inactive nucleotide-binding domain, followed by the drug transport channel and membrane-facing regions, highlighting the importance of the inactive nucleotide-binding domain in facilitating indirect drug efflux in ABCC1. The identified key mutations in endometrial cancer and mapped common mutations present across different types of cancers in ABCB1, ABCC1, and ABCG2 will facilitate the design and discovery of inhibitors targeting unexplored structural regions of these transporters and re-engineering of these transporters to tackle chemoresistance.

Emerging Role of ABC Transporters in Glia Cells in Health and Diseases of the Central Nervous System

ATP-binding cassette (ABC) transporters play a crucial role for the efflux of a wide range of substrates across different cellular membranes. In the central nervous system (CNS), ABC transporters have recently gathered significant attention due to their pivotal involvement in brain physiology and neurodegenerative disorders, such as Alzheimer's disease (AD). Glial cells are fundamental for normal CNS function and engage with several ABC transporters in different ways. Here, we specifically highlight ABC transporters involved in the maintenance of brain homeostasis and their implications in its metabolic regulation. We also show new aspects related to ABC transporter function found in less recognized diseases, such as Huntington's disease (HD) and experimental autoimmune encephalomyelitis (EAE), as a model for multiple sclerosis (MS). Understanding both their impact on the physiological regulation of the CNS and their roles in brain diseases holds promise for uncovering new therapeutic options. Further investigations and preclinical studies are warranted to elucidate the complex interplay between glial ABC transporters and physiological brain functions, potentially leading to effective therapeutic interventions also for rare CNS disorders.

Machine learning unveils immune-related signature in multicenter glioma studies

In glioma molecular subtyping, existing biomarkers are limited, prompting the development of new ones. We present a multicenter study-derived consensus immune-related and prognostic gene signature (CIPS) using an optimal risk score model and 101 algorithms. CIPS, an independent risk factor, showed stable and powerful predictive performance for overall and progression-free survival, surpassing traditional clinical variables. The risk score correlated significantly with the immune microenvironment, indicating potential sensitivity to immunotherapy. High-risk groups exhibited distinct chemotherapy drug sensitivity. Seven signature genes, including IGFBP2 and TNFRSF12A, were validated by qRT-PCR, with higher expression in tumors and prognostic relevance. TNFRSF12A, upregulated in GBM, demonstrated inhibitory effects on glioma cell proliferation, migration, and invasion. CIPS emerges as a robust tool for enhancing individual glioma patient outcomes, while IGFBP2 and TNFRSF12A pose as promising tumor markers and therapeutic targets.

On the Importance of Acidity in Cancer Cells and Therapy

Cancer cells are associated with high glycolytic activity, which results in acidification of the tumor microenvironment. The occurrence of this stressful condition fosters tumor aggressiveness, with the outcome of invasiveness and metastasis that are linked to a poor clinical prognosis. Acidosis can be both the cause or consequence of alterations in the functions and expressions of transporters involved in intracellular acidity regulation. This review aims to explore the origin of acidity in cancer cells and the various mechanisms existing in tumors to resist, survive, or thrive in the acidic environment. It highlights the difficulties in measuring the intracellular pH evolution that impedes our understanding of the many regulatory and feedback mechanisms. It finally presents the consequences of acidity on tumor development as well as the friend or foe role of acidity in therapy.

Transcriptomic and metabolomic analysis of the mechanisms underlying stress responses of the freshwater snail, Pomacea canaliculata, exposed to different levels of arsenic

Arsenic (As) pollution poses an important problem, but limited information is available about the physiological effects of As on freshwater invertebrates. Here, we investigated the physiological effects of chronic As exposure on Pomacea canaliculata, a freshwater invertebrate. High level of As (Ⅲ, 5 mg/L) inhibited the growth of P. canaliculata, whereas low level of As (Ⅲ, 2 mg/L) promoted growth. Pathological changes in shell and cellular ultrastructure due to As accumulation likely explain the growth inhibition at high As level. Low level of As simulated the expression of genes related to DNA replication and chitosan biosynthesis, potentially accounting for the growth promotion observed. High level of As enrichment pathways primarily involved cytochrome P450, glutathione, and arachidonic acid-mediated metabolism of xenobiotics. ATP-binding cassette (ABC) transporters, specifically the ABCB and ABCC subfamilies, were involved in As transport. Differential metabolites were mainly associated with the metabolism and biosynthesis of amino acids. These findings elucidate the dose-dependent effects of As stress on P. canaliculata growth, with low levels promoting and high levels inhibiting. Additionally, our findings also provide insights into As metabolism and transport in P. canaliculata.

Blood-brain barrier transporters: An overview of function, dysfunction in Alzheimer's disease and strategies for treatment

The blood-brain-barrier (BBB) has a major function in maintaining brain homeostasis by regulating the entry of molecules from the blood to the brain. Key players in BBB function are BBB transporters which are highly expressed in brain endothelial cells (BECs) and critical in mediating the exchange of nutrients and waste products. BBB transporters can also influence drug delivery into the brain by inhibiting or facilitating the entry of brain targeting therapeutics for the treatment of brain disorders, such as Alzheimer's disease (AD). Recent studies have shown that AD is associated with a disrupted BBB and transporter dysfunction, although their roles in the development in AD are not fully understand. Modulation of BBB transporter activity may pose a novel approach to enhance the delivery of drugs to the brain for enhanced treatment of AD. In this review, we will give an overview of key functions of BBB transporters and known changes in AD. In addition, we will discuss current strategies for transporter modulation for enhanced drug delivery into the brain.

Correlation between ABCB1 and OLIG2 polymorphisms and the severity and prognosis of patients with cerebral infarction

This study investigated the relationship between ATP-binding cassette sub-family B member 1 (ABCB1) and OLIG2 single nucleotide polymorphism (SNP) and neurological injury severity and outcome in cerebral infarction (CI). The neurological injury severity of 298 CI patients was evaluated by the National Institutes of Health Stroke Scale. The prognosis of CI patients at 30 days after admission was evaluated by the modified Rankin Scale. And 322 healthy people were selected as the control group. The SNPs of the ABCB1 gene (rs1045642) and OLIG2 gene (rs1059004 and rs9653711) were detected by TaqMan probe PCR, and the distribution of SNPs genotype was analyzed. SNP rs9653711 was correlated with CI. Recessive models of rs1045642 and rs9653711 were correlated with CI. The genotypes of rs1045642 and rs9653711 and genetic models were associated with CI severity. rs1045642 had no correlation with CI prognosis, while rs9653711 had less correlation. The genotype distribution and recessive model were associated with CI prognosis. SNP rs1059004 was not associated with CI severity and prognosis. Alcohol consumption, hypertension, diabetes, hyperlipidemia, and high levels of homocysteine (HCY) were independent risk factors for CI, while hypertension, hyperlipidemia, and HCY were associated with poor prognosis of CI. ABCB1 rs1045642 and OLOG2 rs9653711 are associated with CI severity.

Electrostatic switch mechanisms of membrane protein trafficking and regulation

Lipid-protein interactions are normally classified as either specific or general. Specific interactions refer to lipid binding to specific binding sites within a membrane protein, thereby modulating the protein's thermal stability or kinetics. General interactions refer to indirect effects whereby lipids affect membrane proteins by modulating the membrane's physical properties, e.g., its fluidity, thickness, or dipole potential. It is not widely recognized that there is a third distinct type of lipid-protein interaction. Intrinsically disordered N- or C-termini of membrane proteins can interact directly but nonspecifically with the surrounding membrane. Many peripheral membrane proteins are held to the cytoplasmic surface of the plasma membrane via a cooperative combination of two forces: hydrophobic anchoring and electrostatic attraction. An acyl chain, e.g., myristoyl, added post-translationally to one of the protein's termini inserts itself into the lipid matrix and helps hold peripheral membrane proteins onto the membrane. Electrostatic attraction occurs between positively charged basic amino acid residues (lysine and arginine) on one of the protein's terminal tails and negatively charged phospholipid head groups, such as phosphatidylserine. Phosphorylation of either serine or tyrosine residues on the terminal tails via regulatory protein kinases allows for an electrostatic switch mechanism to control trafficking of the protein. Kinase action reduces the positive charge on the protein's tail, weakening the electrostatic attraction and releasing the protein from the membrane. A similar mechanism regulates many integral membrane proteins, but here only electrostatic interactions are involved, and the electrostatic switch modulates protein activity by altering the stabilities of different protein conformational states.

Oral Porphyromonas gingivalis infection affects intestinal microbiota and promotes atherosclerosis

AIM

The link between periodontitis and intestinal dysbiosis, two factors that contribute to atherosclerosis, has not been clearly defined. We investigated the integrative effects of oral infection with Porphyromonas gingivalis (PG), the major pathogen for periodontitis, on intestinal microbiota and atherosclerosis.

MATERIALS AND METHODS

ApoE-/- mice were fed a normal chow diet (NC), a Western diet (WD) or a WD with oral PG infection (PG). The PG infection was investigated by placing a total of 109 CFUs of live PG into the oral cavity of each mouse using a feeding needle five times a week for 3 weeks. Atherosclerotic lesions of the aortae were measured, and blood lipoproteins and the expression of molecules related to lipid metabolism in the liver were analysed. We also performed 16S RNA sequencing and a microbiome analysis using faeces.

RESULTS

En face bloc preparation of the aortae showed that the PG group had a 1.7-fold increase in atherosclerotic lesions compared with the WD group (p < .01). Serum analyses showed that oral PG infection induced a significant decrease in high-density lipoprotein (HDL) and triglyceride. Western blots of hepatic tissue lysates revealed that PG infection reduced the expression of scavenger receptor class B type 1 (SR-B1) in the liver by 50%. Faecal microbiota analysis revealed that species richness estimates (Chao1, ACE) decreased immediately after PG infection. PG infection also induced a significant decrease in Shannon diversity and an increase in Simpson's indices in the WD-fed mice. PG infection significantly increased the phyla Actinobacteria and Deferribacteres, along with the species Mucispirillum schaedleri and Lactobacillus gasseri, in the mice. The functional study showed that PG infection increased the expression of proteins that function in carbohydrate and glucose metabolism, including phosphotransferase system (PTS) proteins and the GntR family transcriptional regulator.

CONCLUSIONS

Oral PG infection promotes atherosclerosis and induces significant metabolic changes, including reduced serum HDL and reduced hepatic SR-B1 and ABCA1 expression, as well as changes in intestinal microbiota. Our study suggests that intestinal dysbiosis accompanies periodontitis and could play a role in atherosclerosis.

Dysregulation of cholesterol metabolism in cancer progression

Cholesterol homeostasis has been implicated in the regulation of cellular and body metabolism. Hence, deregulated cholesterol homeostasis leads to the development of many diseases such as cardiovascular diseases, and neurodegenerative diseases, among others. Recent studies have unveiled the connection between abnormal cholesterol metabolism and cancer development. Cholesterol homeostasis at the cellular level dynamically circulates between synthesis, influx, efflux, and esterification. Any dysregulation of this dynamic process disrupts cholesterol homeostasis and its derivatives, which potentially contributes to tumor progression. There is also evidence that cancer-related signals, which promote malignant progression, also regulate cholesterol metabolism. Here, we described the relationship between cholesterol metabolism and cancer hallmarks, with particular focus on the molecular mechanisms, and the anticancer drugs that target cholesterol metabolism.

The β Isoform of Human ATP-Binding Cassette B5 Transporter, ABCB5β, Localizes to the Endoplasmic Reticulum

ABCB5β is a member of the ABC transporter superfamily cloned from melanocytes. It has been reported as a marker of skin progenitor cells and melanoma stem cells. ABCB5β has also been shown to exert an oncogenic activity and promote cancer metastasis. However, this protein remains poorly characterized. To elucidate its subcellular localization, we tested several anti-ABCB5 antibodies and prepared several tagged ABCB5β cDNA constructs. We then used a combination of immunofluorescence and biochemical analyses to investigate the presence of ABCB5β in different subcellular compartments of HeLa and MelJuSo cell lines. Treatment of the cells with the proteasome inhibitor MG132 showed that part of the population of newly synthesized ABCB5β is degraded by the proteasome system. Interestingly, treatment with SAHA, a molecule that promotes chaperone-assisted folding, largely increased the expression of ABCB5β. Nevertheless, the overall protein distribution in the cells remained similar to that of control conditions; the protein extensively colocalized with the endoplasmic reticulum marker calnexin. Taken together with cell surface biotinylation studies demonstrating that the protein does not reach the plasma membrane (even after SAHA treatment), the data indicate that ABCB5β is a microsomal protein predominantly localized to the ER.

Plasma lipidomic analysis to investigate putative biomarkers of P-glycoprotein activity in healthy volunteers

P-glycoprotein (P-gp) is an efflux transporter involved in the bioavailability of many drugs currently on the market. P-gp is responsible for several drug-drug interactions encountered in clinical practice leading to iatrogenic hospital admissions, especially in polypharmacy situations. ABCB1 genotyping only reflects an indirect estimate of P-gp activity. Therefore, it would be useful to identify endogenous biomarkers to determine the P-gp phenotype to predict in vivo activity prior to the initiation of treatment and to assess the effects of drugs on P-gp activity. The objective of this study was to assess changes in plasma lipidome composition among healthy volunteers selected on the basis of their ABCB1 genotype and who received clarithromycin, a known inhibitor of P-gp. Untargeted lipidomic analysis based on liquid chromatography-tandem mass spectrometry was performed before and after clarithromycin administration. Our results revealed changes in plasma levels of some ceramides (Cers) {Cer(d18:1/22:0), Cer(d18:1/22:1), and Cer(d18:1/20:0) by ~38% (p < 0.0001), 13% (p < 0.0001), and 13% (p < 0.0001), respectively} and phosphatidylcholines (PCs) {PC(17:0/14:1), PC(16:0/18:3), and PC(14:0/18:3) by ~24% (p < 0.001), 10% (p < 0.001), and 23.6% (p < 0.001)} associated with both ABCB1 genotype and clarithromycin intake. Through the examination of plasma lipids, our results highlight the relevance of untargeted lipidomics for studying in vivo P-gp activity and, more generally, to safely phenotyping transporters.

Functional analysis of bacterial genes accidentally packaged in rhizospheric phageome of the wild plant species Abutilon fruticosum

The study aimed to reveal the structure and function of phageome existing in soil rhizobiome of Abutilon fruticosum in order to detect accidentally-packaged bacterial genes that encode Carbohydrate-Active enZymes (or CAZymes) and those that confer antibiotic resistance (e.g., antibiotic resistance genes or ARGs). Highly abundant genes were shown to mainly exist in members of the genera Pseudomonas, Streptomyces, Mycobacterium and Rhodococcus. Enriched CAZymes belong to glycoside hydrolase families GH4, GH6, GH12, GH15 and GH43 and mainly function in D-glucose biosynthesis via 10 biochemical passages. Another enriched CAZyme, e.g., alpha-galactosidase, of the GH4 family is responsible for the wealth of different carbohydrate forms in rhizospheric soil sink of A. fruticosum. ARGs of this phageome include the soxR and OleC genes that participate in the "antibiotic efflux pump" resistance mechanism, the parY mutant gene that participates in the "antibiotic target alteration" mechanism and the arr-1, iri, and AAC(3)-Ic genes that participate in the "antibiotic inactivation" mechanism. It is claimed that the genera Streptomyces, which harbors phages with oleC and parY mutant genes, and Pseudomonas, which harbors phages with soxR and AAC(3)-Ic genes, are approaching multidrug resistance via newly disseminating phages. These ARGs inhibit many antibiotics including oleandomycin, tetracycline, rifampin and aminoglycoside. The study highlights the possibility of accidental packaging of these ARGs in soil phageome and the risk of their horizontal transfer to human gut pathogens through the food chain as detrimental impacts of soil phageome of A. fruticosum. The study also emphasizes the beneficial impacts of phageome on soil microbiome and plant interacting in storing carbohydrates in the soil sink for use by the two entities upon carbohydrate deprivation.

Reconstitution of ATP-dependent lipid transporters: gaining insight into molecular characteristics, regulation, and mechanisms

Lipid transporters play a crucial role in supporting essential cellular processes such as organelle assembly, vesicular trafficking, and lipid homeostasis by driving lipid transport across membranes. Cryo-electron microscopy has recently resolved the structures of several ATP-dependent lipid transporters, but functional characterization remains a major challenge. Although studies of detergent-purified proteins have advanced our understanding of these transporters, in vitro evidence for lipid transport is still limited to a few ATP-dependent lipid transporters. Reconstitution into model membranes, such as liposomes, is a suitable approach to study lipid transporters in vitro and to investigate their key molecular features. In this review, we discuss the current approaches for reconstituting ATP-driven lipid transporters into large liposomes and common techniques used to study lipid transport in proteoliposomes. We also highlight the existing knowledge on the regulatory mechanisms that modulate the activity of lipid transporters, and finally, we address the limitations of the current approaches and future perspectives in this field.

Importance of ABC Transporters in the Survival of Parasitic Nematodes and the Prospect for the Development of Novel Control Strategies

ABC transporters, a family of ATP-dependent transmembrane proteins, are responsible for the active transport of a wide range of molecules across cell membranes, including drugs, toxins, and nutrients. Nematodes possess a great diversity of ABC transporters; however, only P-glycoproteins have been well-characterized compared to other classes. The ABC transport proteins have been implicated in developing resistance to various classes of anthelmintic drugs in parasitic nematodes; their role in plant and human parasitic nematodes still needs further investigation. Therefore, ABC transport proteins offer a potential opportunity to develop nematode control strategies. Multidrug resistance inhibitors are becoming more attractive for controlling nematodes due to their potential to increase drug efficacy in two ways: (i) by limiting drug efflux from nematodes, thereby increasing the amount of drug that reaches its target site, and (ii) by reducing drug excretion by host animals, thereby enhancing drug bioavailability. This article reviews the role of ABC transporters in the survival of parasitic nematodes, including the genes involved, their regulation and physiological roles, as well as recent developments in their characterization. It also discusses the association of ABC transporters with anthelmintic resistance and the possibility of targeting them with next-generation inhibitors or nutraceuticals (e.g., polyphenols) to control parasitic infections.

Role of bacterial efflux pumps in antibiotic resistance, virulence, and strategies to discover novel efflux pump inhibitors

The problem of antibiotic resistance among pathogenic bacteria has reached a crisis level. The treatment options against infections caused by multiple drug-resistant bacteria are shrinking gradually. The current pace of the discovery of new antibacterial entities is lagging behind the rate of development of new resistance. Efflux pumps play a central role in making a bacterium resistant to multiple antibiotics due to their ability to expel a wide range of structurally diverse compounds. Besides providing an escape from antibacterial compounds, efflux pumps are also involved in bacterial stress response, virulence, biofilm formation, and altering host physiology. Efflux pumps are unique yet challenging targets for the discovery of novel efflux pump inhibitors (EPIs). EPIs could help rejuvenate our currently dried pipeline of antibacterial drug discovery. The current article highlights the recent developments in the field of efflux pumps, challenges faced during the development of EPIs and potential approaches for their development. Additionally, this review highlights the utility of resources such as natural products and machine learning to expand our EPIs arsenal using these latest technologies.

Prandial state and biological sex modulate clinically relevant efflux transporters to different extents in Wistar and Sprague Dawley rats

P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 2 (MRP2) are clinically relevant efflux transporters implicated in the oral absorption of many food and drug substrates. Here, we hypothesised that food intake could influence protein and mRNA intestinal expression of P-gp/abcb1a, BCRP/abcg2, and MRP2/abcc2 differently in male and female Wistar and Sprague Dawley rats. To test this hypothesis, we used enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (PCR) to quantify the protein and mRNA intestinal expression of these transporters, respectively. Our study found food and sex differences in P-gp expression, whereby in the fed state P-gp expression decreased in male Wistar rats, but P-gp expression increased in females. In the fed state, BCRP expression increased in both male and female Wistar rats, compared with the fasted state. In contrast, no sex differences or food effect differences were seen in Sprague Dawley rats for P-gp and BCRP expression. On the other hand, in the fed state, MRP2 expression was higher in male and female Wistar and Sprague Dawley rats when compared with the fasted state. Sex differences were also observed in the fasted state. Overall, significant strain differences were reported for P-gp, BCRP and MRP2 expression. Strong to moderate positive linear correlations were found between ELISA and PCR quantification methods. ELISA may be more useful than PCR as it reports protein expression as opposed to transcript expression. Researchers must consider the influence of sex, strain and feeding status in preclinical studies of P-gp, BCRP and MRP2 drug substrates.

Myoinositol and methyl stearate increases rifampicin susceptibility among drug-resistant Mycobacterium tuberculosis expressing Rv1819c

The alarming increase in multidrug resistance, which includes Bedaquiline and Delamanid, stumbles success in Tuberculosis treatment outcome. Mycobacterium tuberculosis gains resistance to rifampicin, which is one of the less toxic and potent anti-TB drugs, through genetic mutations predominantly besides efflux pump mediated drug resistance. In recent decades, scientific interventions are being carried out to overcome this hurdle using novel approaches to save this drug by combining it with other drugs/molecules or by use of high dose rifampicin. This study reports five small molecules namely Ellagic acid, Methyl Stearate, Myoinositol, Rutin, and Shikimic acid that exhibit synergistic inhibitory activity with rifampicin against resistant TB isolates. In-silico examinations revealed possible blocking of Rv1819c-an ABC transporter efflux pump that was known to confer resistance in M. tuberculosis to rifampicin. The synergistic anti-TB activity was assessed using a drug combination checkerboard assay. Efflux pump inhibition activity of ellagic acid, myoinositol, and methyl stearate was observed through ethidium bromide accumulation assay in the drug-resistant M. tuberculosis clinical strains and recombinant Mycobacterium smegmatis expressing Rv1819c in coherence with the significant reduction in the minimum inhibitory concentration of rifampicin. Cytotoxicity of the active efflux inhibitors was tested using in silico and ex vivo methods. Myoinositol and methyl stearate were completely non-toxic to the hematological and epithelial cells of different organs under ex vivo conditions. Based on these findings, these molecules can be considered for adjunct TB therapy; however, their impact on other drugs of anti-TB regimen needs to be tested.

ATP-binding cassette efflux transporters and MDR in cancer

Of the many known multidrug resistance (MDR) mechanisms, ATP-binding cassette (ABC) transporters expelling drug molecules out of cells is a major factor limiting the efficacy of present-day anticancer drugs. In this review, we highlights updated information on the structure, function, and regulatory mechanisms of major MDR-related ABC transporters, such as P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), and breast cancer resistance protein (BCRP), and the effect of modulators on their functions. We also provide focused information on different modulators of ABC transporters that could be utilized against the emerging MDR crisis in cancer treatment. Finally, we discuss the importance of ABC transporters as therapeutic targets in light of future strategic planning for translating ABC transporter inhibitors into clinical practice.

The Role of ABC Transporters in Skin Cells Exposed to UV Radiation

ABC transporters are expressed in skin cells to protect them against harmful xenobiotics. Moreover, these transmembrane proteins have a number of additional functions that ensure skin homeostasis. This review summarizes the current knowledge about the role of specific ABC proteins in the skin, including multi-drug resistance transporters (MDR1/3), the transporter associated with antigen processing 1/2 (TAP1/2), the cystic fibrosis transmembrane conductance regulator (CFTR), sulfonylurea receptors (SUR1/2), and the breast cancer resistance protein (BCRP). Additionally, the effect of UV radiation on ABC transporters is shown. The exposure of skin cells to UV radiation often leads to increased activity of ABC transporters-as has been observed in the case of MDRs, TAPs, CFTR, and BCRP. A different effect of oxidative stress has been observed in the case of mitochondrial SURs. However, the limited data in the literature-as indicated in this article-highlights the limited number of experimental studies dealing with the role of ABC transporters in the physiology and pathophysiology of skin cells and the skin as a whole. At the same time, the importance of such knowledge in relation to the possibility of daily exposure to UV radiation and xenobiotics, used for both skin care and the treatment of its diseases, is emphasized.

Integrative methylome and transcriptome analysis of porcine abdominal fat indicates changes in fat metabolism and immune responses during different development

Fat is involved in synthesizing fatty acids (FAs), FA circulation, and lipid metabolism. Various genetic studies have been conducted on porcine fat but understanding the growth and specific adipose tissue is insufficient. The purpose of this study is to investigate the epigenetic difference in abdominal fat according to the growth of porcine. The samples were collected from the porcine abdominal fat of different developmental stages (10 and 26 weeks of age). Then, the samples were sequenced using MBD-seq and RNA-seq for profiling DNA methylation and RNA expression. In 26 weeks of age pigs, differentially methylated genes (DMGs) and differentially expressed genes (DEGs) were identified as 2,251 and 5,768, compared with 10 weeks of age pigs, respectively. Gene functional analysis was performed using GO and KEGG databases. In functional analysis results of DMGs and DEGs, immune responses such as chemokine signaling pathways, B cell receptor signaling pathways, and lipid metabolism terms such as PPAR signaling pathways and fatty acid degradation were identified. It is thought that there is an influence between DNA methylation and gene expression through changes in genes with similar functions. The effects of DNA methylation on gene expression were investigated using cis-regulation and trans-regulation analysis to integrate and interpret different molecular layers. In the cis-regulation analysis using 629 overlapping genes between DEGs and DMGs, immune response functions were identified, while in trans-regulation analysis through the TF-target gene network, the co-expression network of lipid metabolism-related functions was distinguished. Our research provides an understanding of the underlying mechanisms for epigenetic regulation in porcine abdominal fat with aging.

The oleaginous yeast Starmerella bombicola reveals limitations of Saccharomyces cerevisiae as a model for fatty acid transport studies

Saccharomyces cerevisiae is the model organism to most yeast researchers, and information obtained from its physiology is generally extrapolated to other yeasts. Studies on fatty acid transport in S. cerevisiae are based on the expression of both native fatty acid export genes as well as heterologous proteins. Starmerella bombicola, on the other hand, is an oleaginous yeast of industrial relevance but its fatty acid transport mechanisms are unknown. In this study, we attempt to use existing knowledge from S. cerevisiae to study fatty acid transport in S. bombicola, but the obtained results differ from those observed in S. cerevisiae. First, we observed that deletion of SbPRY1 in S. bombicola leads to higher fatty acid export, the opposite effect to the one previously observed for the Pry homologues in S. cerevisiae. Second, following reports that human FATP1 could export fatty acids and alcohols in S. cerevisiae, we expressed FATP1 in a fatty acid-accumulating S. bombicola strain. However, FATP1 reduced fatty acid export in S. bombicola, most likely due to its acyl-CoA synthetase activity. These results not only advance knowledge on fatty acid physiology of S. bombicola, but also improve our understanding of S. cerevisiae and its limitations as a model organism.

Fatty acid uptake in Trypanosoma brucei: Host resources and possible mechanisms

Trypanosoma brucei spp. causes African Sleeping Sickness in humans and nagana, a wasting disease, in cattle. As T. brucei goes through its life cycle in its mammalian and insect vector hosts, it is exposed to distinct environments that differ in their nutrient resources. One such nutrient resource is fatty acids, which T. brucei uses to build complex lipids or as a potential carbon source for oxidative metabolism. Of note, fatty acids are the membrane anchoring moiety of the glycosylphosphatidylinositol (GPI)-anchors of the major surface proteins, Variant Surface Glycoprotein (VSG) and the Procyclins, which are implicated in parasite survival in the host. While T. brucei can synthesize fatty acids de novo, it also readily acquires fatty acids from its surroundings. The relative contribution of parasite-derived vs. host-derived fatty acids to T. brucei growth and survival is not known, nor have the molecular mechanisms of fatty acid uptake been defined. To facilitate experimental inquiry into these important aspects of T. brucei biology, we addressed two questions in this review: (1) What is known about the availability of fatty acids in different host tissues where T. brucei can live? (2) What is known about the molecular mechanisms mediating fatty acid uptake in T. brucei? Finally, based on existing biochemical and genomic data, we suggest a model for T. brucei fatty acid uptake that proposes two major routes of fatty acid uptake: diffusion across membranes followed by intracellular trapping, and endocytosis of host lipoproteins.

ATP-Binding Cassette Protein ABCC10 Deficiency Prevents Diet-Induced Obesity but Not Atherosclerosis in Mice

Excess plasma lipid levels are a risk factor for various cardiometabolic disorders. Studies have shown that improving dyslipidemia lowers the progression of these disorders. In this study, we investigated the role of ATP-binding cassette transporter C10 (ABCC10) in regulating lipid metabolism. Our data indicate that deletion of the Abcc10 gene in male mice results in lower plasma and intestinal triglycerides by around 38% and 36%, respectively. Furthermore, deletion of ABCC10 ameliorates diet-induced obesity in mice and leads to a better response during insulin and glucose tolerance tests. Unexpectedly, ABCC10 deficiency does not affect triglyceride levels or atherosclerosis in ApoE-deficient mice. In addition, our studies demonstrate low oleate uptake by enterocytes (~25-30%) and less absorption (~37%) of triglycerides in the small intestine of ABCC10 knockout mice. Deletion of the Abcc10 gene also alters several lipid metabolism genes in the intestine, suggesting that ABCC10 regulates dietary fat absorption, which may contribute to diet-induced obesity in mice.

The Importance of the Plasma Membrane in Atherogenesis

Atherosclerotic cardiovascular diseases are an important medical problem due to their high prevalence, impact on quality of life and prognosis. The pathogenesis of atherosclerosis is an urgent medical and social problem, the solution of which may improve the quality of diagnosis and treatment of patients. Atherosclerosis is a complex chain of events, which proceeds over many years and in which many cells in the bloodstream and the vascular wall are involved. A growing body of evidence suggests that there are complex, closely linked molecular mechanisms that occur in the plasma membranes of cells involved in atherogenesis. Lipid transport, innate immune system receptor function, and hemodynamic regulation are linked to plasma membranes and their biophysical properties. A better understanding of these interrelationships will improve diagnostic quality and treatment efficacy.

Sphingosine-1-Phosphate (S1P) Lyase Inhibition Aggravates Atherosclerosis and Induces Plaque Rupture in ApoE−/− Mice

Altered plasma sphingosine-1-phosphate (S1P) concentrations are associated with clinical manifestations of atherosclerosis. However, whether long-term elevation of endogenous S1P is pro- or anti-atherogenic remains unclear. Here, we addressed the impact of permanently high S1P levels on atherosclerosis in cholesterol-fed apolipoprotein E-deficient (ApoE^−/−) mice over 12 weeks. This was achieved by pharmacological inhibition of the S1P-degrading enzyme S1P lyase with 4-deoxypyridoxine (DOP). DOP treatment dramatically accelerated atherosclerosis development, propagated predominantly unstable plaque phenotypes, and resulted in frequent plaque rupture with atherothrombosis. Macrophages from S1P lyase-inhibited or genetically deficient mice had a defect in cholesterol efflux to apolipoprotein A-I that was accompanied by profoundly downregulated cholesterol transporters ATP-binding cassette transporters ABCA1 and ABCG1. This was dependent on S1P signaling through S1PR3 and resulted in dramatically enhanced atherosclerosis in ApoE^−/−/S1PR3^−/− mice, where DOP treatment had no additional effect. Thus, high endogenous S1P levels promote atherosclerosis, compromise cholesterol efflux, and cause genuine plaque rupture.

Targeting ABCC6 in Mesenchymal Stem Cells: Impairment of Mature Adipocyte Lipid Homeostasis

Mutations in ABCC6, an ATP-binding cassette transporter with a so far unknown substrate mainly expressed in the liver and kidney, cause pseudoxanthoma elasticum (PXE). Symptoms of PXE in patients originate from the calcification of elastic fibers in the skin, eye, and vessels. Previous studies suggested an involvement of ABCC6 in cholesterol and lipid homeostasis. The intention of this study was to examine the influence of ABCC6 deficiency during adipogenic differentiation of human bone marrow-derived stem cells (hMSCs). Induction of adipogenic differentiation goes along with significantly elevated ABCC6 gene expression in mature adipocytes. We generated an ABCC6-deficient cell culture model using clustered regulatory interspaced short palindromic repeat Cas9 (CRISPR–Cas9) system to clarify the role of ABCC6 in lipid homeostasis. The lack of ABCC6 in hMSCs does not influence gene expression of differentiation markers in adipogenesis but results in a decreased triglyceride content in cell culture medium. Protein and gene expression analysis of mature ABCC6-deficient adipocytes showed diminished intra- and extra-cellular lipolysis, release of lipids, and fatty acid neogenesis. Therefore, our results demonstrate impaired lipid trafficking in adipocytes due to ABCC6 deficiency, highlighting adipose tissue and peripheral lipid metabolism as a relevant target for uncovering systemic PXE pathogenesis.

Ether lipid transfer across the blood-brain and placental barriers does not improve by inactivation of the most abundant ABC transporters

Phospholipid transport from the periphery to the brain is an understudied topic. When certain lipid species are deficient due to impaired synthesis, though, transfer across the blood-brain barrier is essential for replenishing lipids in the brain. For example, the deficiency in plasmalogens, the most abundant ether lipids in mammals, has detrimental effects on the brain, which is a major issue in inherited peroxisomal disorders but also contributes to more common disorders like Alzheimer's disease. Oral administration of alkylglycerols like batyl alcohol, which carry a pre-formed ether bond, enables replenishment of ether lipids in various peripheral tissues. However, plasmalogen deficiency in the brain cannot be overcome by this approach. Here, we tried to increase cerebral plasmalogen uptake by modulating the efflux transport across the blood-brain barrier. We hypothesized, based on previous literature, that at least some ether lipid species readily enter endothelial cells of the barrier through the transporter MFSD2A but are re-exported by ATP-binding cassette (ABC) transporters. By crossbreeding Mdr1a^-/-/Mdr1b^-/-/Bcrp^-/- and ether lipid-deficient Gnpat^-/- mice as well as pharmacological inhibition with MK-571 to inactivate the major ABC transporters at the blood-brain barrier, we evaluated the potential of combined ABC transporter inhibition and oral batyl alcohol administration for the treatment of plasmalogen deficiency. We found that even in the absence of the most abundant ABC transporters, batyl alcohol supplementation did not restore plasmalogen levels in the brain, despite the presence of a wide spectrum of ether lipid subspecies in the plasma as demonstrated by lipidomic analysis. Surprisingly, batyl alcohol treatment of pregnant Gnpat^+/- dams had beneficial effects on the plasmalogen levels of Gnpat^-/- offspring with defective ether lipid biosynthesis, independently of ABC transporter status at the placental barrier. Our results underline the autonomy of brain lipid homeostasis and indicate that peripheral supplementation of ether lipids is not sufficient to supply the brain with larger amounts of plasmalogens. Yet, the findings suggest that alkylglycerol treatment during pregnancy may pose a viable option to ameliorate some of the severe developmental defects of inborn ether lipid deficiency.

ABC transporters in breast cancer: their roles in multidrug resistance and beyond

ATP-binding cassette (ABC) transporters are membrane-spanning proteins involved in cholesterol homeostasis, transport of various molecules in and out of cells and organelles, oxidative stress, immune recognition, and drug efflux. They are long implicated in the development of multidrug resistance in cancer chemotherapy. Existing clinical and molecular evidence has also linked ABC transporters with cancer pathogenesis, prognostics, and therapy. In this review, we aim to provide a comprehensive update on all ABC transporters and their roles in drug resistance in breast cancer (BC). For solid tumours such as BC, various ABC transporters are highly expressed in less differentiated subtypes and metastases. ABCA1, ABCB1 and ABCG2 are key players in BC chemoresistance. Restraining these transporters has evolved as a possible mechanism to reverse this phenomenon. Further, ABCB1 and ABCC1 are important in BC prognosis. Newer therapeutic approaches have been developed to target all these molecules to dysregulate their effect, reduce cell viability, induce apoptosis, and increase drug sensitivity. In the future, targeted therapy for specific genetic variations and upstream or downstream molecules can help improve patient prognosis.

Identification of ABCA5 among ATP-Binding Cassette Transporter Family as a New Biomarker for Colorectal Cancer

Background

The increasing incidence and mortality of colorectal cancer (CRC) urgently requires updated biomarkers. The ABC transporter family is a widespread family of membrane-bound proteins involved in the transportation of substrates associated with ATP hydrolysis, including metabolites, amino acids, peptides and proteins, sterols and lipids, organic and inorganic ions, sugars, metals, and drugs. They play an important role in the maintenance of homeostasis in the body.

Purpose

This study aims to search for new markers in the ABC transporter gene family for diagnostic and prognostic purposes through data mining of The Cancer Genome Atlas (TCGA) and GEO (Gene Expression Omnibus) datasets.

Methods

A total of 980 samples, including 684 CRC patients and 296 controls from five different datasets, were included for analysis. The construction of the PPI (protein-protein interaction) network and pathway analysis were performed in STRING database and DAVID (database for annotation, visualization, and integrated discovery), respectively. In addition, GSEA (gene set enrichment analysis) and WGCNA (weighted gene co-expression network analysis) were also used for functional analysis.

Results

After several rounds of screening and validation, only the ABCB5 gene was retained among the 49 genes.

Conclusions

The results demonstrated that ABCA5 expression is reduced in CRC and patients with high ABCA5 expression have better OS, which can provide guidance for better management and treatment of CRC in the future.

Early seed development requires the A-type ATP-binding cassette protein ABCA10

A-type ATP-binding cassette (ABCA) proteins transport lipids and lipid-based molecules in humans, and their malfunction is associated with various inherited diseases. Although plant genomes encode many ABCA transporters, their molecular and physiological functions remain largely unknown. Seeds are rapidly developing organs that rely on the biosynthesis and transport of large quantities of lipids to generate new membranes and storage lipids. In this study, we characterized the Arabidopsis (Arabidopsis thaliana) ABCA10 transporter, which is selectively expressed in female gametophytes and early developing seeds. By 3 d after flowering (DAF), seeds from the abca10 loss-of-function mutant exhibited a smaller chalazal endosperm than those of the wild-type. By 4 DAF, their endosperm nuclei occupied a smaller area than those of the wild-type. The endosperm nuclei of the mutants also failed to distribute evenly inside the seed coat and stayed aggregated instead, possibly due to inadequate expansion of abca10 endosperm. This endosperm defect might have retarded abca10 embryo development. At 7 DAF, a substantial portion of abca10 embryos remained at the globular or earlier developmental stages, whereas wild-type embryos were at the torpedo or later stages. ABCA10 is likely involved in lipid metabolism, as ABCA10 overexpression induced the overaccumulation of triacylglycerol but did not change the carbohydrate or protein contents in seeds. In agreement, ABCA10 localized to the endoplasmic reticulum (ER), the major site of lipid biosynthesis. Our results reveal that ABCA10 plays an essential role in early seed development, possibly by transporting substrates for lipid metabolism to the ER.

Gut Microbiota Dysbiosis and Altered Bile Acid Catabolism Lead to Metabolic Disorder in Psoriasis Mice

Patients with psoriasis tend to have significant comorbidities, such as hyperlipemia, diabetes mellitus, and obesity, which belong to metabolic disorders. The specific mechanism through which psoriasis increases the metabolic disorder risk is uncertain. In this study, we demonstrated that the dysbiotic gut microbiota of 6-month-old psoriasis-like model mice (K14-VEGF-A-transgenic) exacerbated psoriasis disease and induced metabolic disorder when transferred into 2-month-old mice. By 16S rRNA gene sequencing, we confirmed that the Parabacteroides distasonis decreased with age in K14-VEGF mice, and P. distasonis also decreased in the transferred mice. Metabolomic screening identified an altered bile acid profile, including a decrease in chenodeoxycholic acid (CDCA) in the feces of transferred mice. Additionally, CDCA supplements prevented metabolic disorders in K14-VEGF-A-transgenic mice. Consequently, we found that aberrant bile acid metabolism may contribute to metabolic disorder in K14-VEGF-A-transgenic mice, indicating the possibility to prevent and treat the metabolic disorder in psoriasis mice by targeting gut microbial metabolites.

A cellular and molecular atlas reveals the basis of chytrid development

The chytrids (phylum Chytridiomycota) are a major fungal lineage of ecological and evolutionary importance. Despite their importance, many fundamental aspects of chytrid developmental and cell biology remain poorly understood. To address these knowledge gaps, we combined quantitative volume electron microscopy and comparative transcriptome profiling to create an 'atlas' of the cellular and molecular basis of the chytrid life cycle, using the model chytrid Rhizoclosmatium globosum. From our developmental atlas, we describe the transition from the transcriptionally inactive free-swimming zoospore to the more biologically complex germling, and show that lipid processing is multifaceted and dynamic throughout the life cycle. We demonstrate that the chytrid apophysis is a compartmentalised site of high intracellular trafficking, linking the feeding/attaching rhizoids to the reproductive zoosporangium, and constituting division of labour in the chytrid cell plan. We provide evidence that during zoosporogenesis, zoospores display amoeboid morphologies and exhibit endocytotic cargo transport from the interstitial maternal cytoplasm. Taken together, our results reveal insights into chytrid developmental biology and provide a basis for future investigations into non-dikaryan fungal cell biology.

Lipid Metabolism and Epigenetics Crosstalk in Prostate Cancer

Prostate cancer (PCa) is the most commonly diagnosed malignant neoplasm in men in the Western world. Localized low-risk PCa has an excellent prognosis thanks to effective local treatments; however, despite the incorporation of new therapeutic strategies, metastatic PCa remains incurable mainly due to disease heterogeneity and the development of resistance to therapy. The mechanisms underlying PCa progression and therapy resistance are multiple and include metabolic reprogramming, especially in relation to lipid metabolism, as well as epigenetic remodelling, both of which enable cancer cells to adapt to dynamic changes in the tumour. Interestingly, metabolism and epigenetics are interconnected. Metabolism can regulate epigenetics through the direct influence of metabolites on epigenetic processes, while epigenetics can control metabolism by directly or indirectly regulating the expression of metabolic genes. Moreover, epidemiological studies suggest an association between a high-fat diet, which can alter the availability of metabolites, and PCa progression. Here, we review the alterations of lipid metabolism and epigenetics in PCa, before focusing on the mechanisms that connect them. We also discuss the influence of diet in this scenario. This information may help to identify prognostic and predictive biomarkers as well as targetable vulnerabilities.

Integrated Transcriptomics and Metabolomics Analyses of Stress-Induced Murine Hair Follicle Growth Inhibition

Psychological stress plays an important role in hair loss, but the underlying mechanisms are not well-understood, and the effective therapies available to regrow hair are rare. In this study, we established a chronic restraint stress (CRS)-induced hair growth inhibition mouse model and performed a comprehensive analysis of metabolomics and transcriptomics. Metabolomics data analysis showed that the primary and secondary metabolic pathways, such as carbohydrate metabolism, amino acid metabolism, and lipid metabolism were significantly altered in skin tissue of CRS group. Transcriptomics analysis also showed significant changes of genes expression profiles involved in regulation of metabolic processes including arachidonic acid metabolism, glutathione metabolism, glycolysis gluconeogenesis, nicotinate and nicotinamide metabolism, purine metabolism, retinol metabolism and cholesterol metabolism. Furthermore, RNA-Seq analyses also found that numerous genes associated with metabolism were significantly changed, such as Hk-1, in CRS-induced hair growth inhibition. Overall, our study supplied new insights into the hair growth inhibition induced by CRS from the perspective of integrated metabolomics and transcriptomics analyses.

Identification of Antibacterial Components in the Methanol-Phase Extract from Edible Herbaceous Plant Rumex madaio Makino and Their Antibacterial Action Modes

Outbreaks and prevalence of infectious diseases worldwide are some of the major contributors to morbidity and morbidity in humans. Pharmacophageous plants are the best source for searching antibacterial compounds with low toxicity to humans. In this study, we identified, for the first time, antibacterial components and action modes of methanol-phase extract from such one edible herbaceous plant Rumex madaio Makino. The bacteriostatic rate of the extract was 75% against 23 species of common pathogenic bacteria. The extract was further purified using the preparative high-performance liquid chromatography (Prep-HPLC) technique, and five separated componential complexes (CC) were obtained. Among these, the CC 1 significantly increased cell surface hydrophobicity and membrane permeability and decreased membrane fluidity, which damaged cell structure integrity of Gram-positive and -negative pathogens tested. A total of 58 different compounds in the extract were identified using ultra-HPLC and mass spectrometry (UHPLC-MS) techniques. Comparative transcriptomic analyses revealed a number of differentially expressed genes and various changed metabolic pathways mediated by the CC1 action, such as down-regulated carbohydrate transport and/or utilization and energy metabolism in four pathogenic strains tested. Overall, the results in this study demonstrated that the CC1 from R. madaio Makino are promising candidates for antibacterial medicine and human health care products.

Transcriptional downregulation of ABC transporters is related to follicular degeneration after vitrification and in vitro culture of ovine ovarian tissue

ATP-binding cassette (ABC) transporters perform multiple functions in reproductive tissues. During ovarian tissue vitrification, the plasma membrane has important functions in the influx or efflux of water, and substances such as cryoprotectants and channel proteins that are required in this process. Thus, the present study aimed to verify the relative abundance of mRNA transcript of ABC transporters ABCB1, ABCG2, and MRP2 after vitrification and in vitro culture (IVC) of ovine ovarian tissue. For this study, the ovarian cortex fragments were proportioned into four groups as fresh control, vitrified control, fresh culture, and vitrified culture groups. After vitrification and in vitro culture, the ovarian tissue was evaluated using morphological procedures. Further, relative abundance of ABCB1, ABCG2, and MRP2 transporter mRNA transcripts in the ovarian cortex subjected to aforementioned treatment conditions were evaluated using qPCR. Our results showed a negative association between degenerated follicles and mRNA transcript abundances of ABCB1 and ABCG2. In addition, the percentage of growing follicles in the ovine ovarian cortex after vitrification was similar to that of the fresh control tissue without in vitro culture. The in vitro culture of fresh and vitrified tissue however, showed a significant decrease in the percentage of growing follicles. To the best of our knowledge, we believe that our data for the first time has studied the relative abundances of ABCB1 and ABCG2 mRNA transcripts in the ovine ovarian cortex. In addition, alterations of these protein channels may be indicative of a deleterious effect of osmotic stress on follicular survival during vitrification. Furthermore, these effects were detectable only after the IVC of the ovarian tissues. Nonetheless, further studies are required to investigate the functions of ABC transporters in ovine folliculogenesis, especially after in vitro culture of ovarian tissue.

ABCA7, a Genetic Risk Factor Associated with Alzheimer's Disease Risk in African Americans

African American/Black adults are twice as likely to have Alzheimer's disease (AD) compared to non-Hispanic White adults. Genetics partially contributes to this disparity in AD risk, among other factors, as there are several genetic variants associated with AD that are more prevalent in individuals of African or European ancestry. The phospholipid-transporting ATPase ABCA7 (ABCA7) gene has stronger associations with AD risk in individuals with African ancestry than in individuals with European ancestry. In fact, ABCA7 has been shown to have a stronger effect size than the apolipoprotein E (APOE) ɛ4 allele in African American/Black adults. ABCA7 is a transmembrane protein involved in lipid homeostasis and phagocytosis. ABCA7 dysfunction is associated with increased amyloid-beta production, reduced amyloid-beta clearance, impaired microglial response to inflammation, and endoplasmic reticulum stress. This review explores the impact of ABCA7 mutations that increase AD risk in African American/Black adults on ABCA7 structure and function and their contributions to AD pathogenesis. The combination of biochemical/biophysical and 'omics-based studies of these variants needed to elucidate their downstream impact and molecular contributions to AD pathogenesis is highlighted.

Neuronal ROS-induced glial lipid droplet formation is altered by loss of Alzheimer's disease-associated genes

A growing list of Alzheimer's disease (AD) genetic risk factors is being identified, but the contribution of each variant to disease mechanism remains largely unknown. We have previously shown that elevated levels of reactive oxygen species (ROS) induces lipid synthesis in neurons leading to the sequestration of peroxidated lipids in glial lipid droplets (LD), delaying neurotoxicity. This neuron-to-glia lipid transport is APOD/E-dependent. To identify proteins that modulate these neuroprotective effects, we tested the role of AD risk genes in ROS-induced LD formation and demonstrate that several genes impact neuroprotective LD formation, including homologs of human ABCA1, ABCA7, VLDLR, VPS26, VPS35, AP2A, PICALM, and CD2AP Our data also show that ROS enhances Aβ42 phenotypes in flies and mice. Finally, a peptide agonist of ABCA1 restores glial LD formation in a humanized APOE4 fly model, highlighting a potentially therapeutic avenue to prevent ROS-induced neurotoxicity. This study places many AD genetic risk factors in a ROS-induced neuron-to-glia lipid transfer pathway with a critical role in protecting against neurotoxicity.

Structure and function of ABCA4 and its role in the visual cycle and Stargardt macular degeneration

ABCA4 is a member of the superfamily of ATP-binding cassette (ABC) transporters that is preferentially localized along the rim region of rod and cone photoreceptor outer segment disc membranes. It uses the energy from ATP binding and hydrolysis to transport N-retinylidene-phosphatidylethanolamine (N-Ret-PE), the Schiff base adduct of retinal and phosphatidylethanolamine, from the lumen to the cytoplasmic leaflet of disc membranes. This ensures that all-trans-retinal and excess 11-cis-retinal are efficiently cleared from photoreceptor cells thereby preventing the accumulation of toxic retinoid compounds. Loss-of-function mutations in the gene encoding ABCA4 cause autosomal recessive Stargardt macular degeneration, also known as Stargardt disease (STGD1), and related autosomal recessive retinopathies characterized by impaired central vision and an accumulation of lipofuscin and bis-retinoid compounds. High resolution structures of ABCA4 in its substrate and nucleotide free state and containing bound N-Ret-PE or ATP have been determined by cryo-electron microscopy providing insight into the molecular architecture of ABCA4 and mechanisms underlying substrate recognition and conformational changes induced by ATP binding. The expression and functional characterization of a large number of disease-causing missense ABCA4 variants have been determined. These studies have shed light into the molecular mechanisms underlying Stargardt disease and a classification that reliably predicts the effect of a specific missense mutation on the severity of the disease. They also provide a framework for developing rational therapeutic treatments for ABCA4-associated diseases.

Characterization of tick salivary gland and saliva alphagalactome reveals candidate alpha-gal syndrome disease biomarkers

BACKGROUND

Ticks are obligate hematophagous arthropods that synthesize the glycan Galα1-3Galβ1-(3)4GlcNAc-R (α-Gal) associated with the alpha-gal syndrome (AGS) or allergy to mammalian meat consumption.

RESEARCH DESIGN AND METHODS

In this study, we used a proteomics approach to characterize tick proteins in salivary glands (sialome SG), secreted saliva (sialome SA) and with α-Gal modification (alphagalactome SG and SA) in model tick species associated with the AGS in the United States (Amblyomma americanum) and Australia (Ixodes holocyclus). Selected proteins reactive to sera (IgE) from patients with AGS were identified to advance in the identification of possible proteins associated with the AGS. For comparative analysis, the α-Gal content was measured in various tick species.

RESULTS

The results confirmed that ticks produce proteins with α-Gal modifications and secreted into saliva during feeding. Proteins identified in tick alphagalactome SA by sera from patients with severe AGS symptomatology may constitute candidate disease biomarkers.

CONCLUSIONS

The results support the presence tick-derived proteins with α-Gal modifications in the saliva with potential implications in AGS and other disorders and protective capacity against tick infestations and pathogen infection. Future research should focus on the characterization of the function of tick glycoproteins with α-Gal in tick biology and AGS.

Diagnostic and prognostic value of ABC transporter family member ABCG1 gene in clear cell renal cell carcinoma

As the most common histologic subtype of renal cancer, clear cell renal cell carcinoma (ccRCC) poses a serious threat to public health. However, there are no specific molecular-targeted drugs for ccRCC at present. Human ATP-binding cassette (ABC) transporter family plays an important role in homeostasis maintenance. This study aimed to evaluate the potential diagnostic value of ABC genes in ccRCC. A total of 952 samples of ccRCC patients (707) and controls (245) from three different datasets were included for analysis. Receiver operating characteristic analysis and t-test were used to analyze the differential expression of ABC genes in ccRCC patients and control samples at mRNA level during screening and validations. The Cancer Genome Atlas (TCGA-ccRCC) dataset was utilized to investigate the correlation between ABC genes expression and prognostic value in ccRCC. We then investigated the interactions between ABCG1 and proteins in the Comparative Toxicogenomics Database (CTD). Finally, we found that ATP-binding cassette transporter G member 1 (ABCG1) was over-expressed in ccRCC patients compared with healthy samples at mRNA level. Cox regression analysis and Kaplan-Meier analysis showed that ccRCC patients with high ABCG1 expression had better overall survival (OS) than those patients with low expression (hazard ratio (HR) = 0.662, p = 0.007). This study demonstrated that ABCG1 is a potential diagnostic and prognostic biomarker in ccRCC and discussed the molecular mechanisms underlying the relationship between ccRCC and ABCG1, which might provide guidance for better management and treatment of ccRCC in the future.

Analysis of ABC Transporter Gene Expression in Atherosclerosis

ABC transporters are a large family of membrane proteins that transport chemically diverse substrates across the cell membrane. Disruption of transport mechanisms mediated by ABC transporters causes the development of various diseases, including atherosclerosis. Methods: A bioinformatic analysis of a dataset from Gene Expression Omnibus (GEO) was performed. A GEO dataset containing data on gene expression levels in samples of atherosclerotic lesions and control arteries without atherosclerotic lesions from carotid, femoral, and infrapopliteal arteries was used for analysis. To evaluate differentially expressed genes, a bioinformatic analysis was performed in comparison groups using the limma package in R (v. 4.0.2) and the GEO2R and Phantasus tools (v. 1.11.0). Results: The obtained data indicate the differential expression of many ABC transporters belonging to different subfamilies. The differential expressions of ABC transporter genes involved in lipid transport, mechanisms of multidrug resistance, and mechanisms of ion exchange are shown. Differences in the expression of transporters in tissue samples from different arteries are established. Conclusions: The expression of ABC transporter genes demonstrates differences in atherosclerotic samples and normal arteries, which may indicate the involvement of transporters in the pathogenesis of atherosclerosis.

Regulatory mechanisms of the bile salt export pump (BSEP/ABCB11) and its role in related diseases

The bile salt export pump (BSEP/ABCB11) is located on the apical membrane and mediates the secretion of bile salts from hepatocytes into the bile. BSEP-mediated bile salt efflux is the rate-limiting step of bile salt secretion and the main driving force of bile flow. BSEP drives and maintains the enterohepatic circulation of bile salts. In recent years, research efforts have been focused on understanding the physiological and pathological functions and regulatory mechanisms of BSEP. These studies elucidated the roles of farnesoid X receptor (FXR), AMP-activated protein kinase (AMPK), liver receptor homolog-1(LRH-1) and nuclear factor erythroid 2-related factor 2 (Nrf-2) in BSEP expression and discovered some regulatory factors which participate in its post-transcriptional regulation. A series of liver diseases have also been shown to be related to BSEP expression and dysfunction, such as cholestasis, drug-induced liver injury, and gallstones. Here, we systematically review and summarize recent literature on BSEP structure, physiological functions, regulatory mechanisms, and related diseases.