Tetrabenazine, a vesicular monoamine transporter 2 inhibitor, inhibits vesicular storage capacity and release of monoamine transmitters in mouse brain tissue.

BACKGROUND AND PURPOSE: Tetrabenazine (TBZ), used for treating hyperkinetic disorders, inhibits vesicular monoamine transporter-2 (VMAT-2), which sequesters monoamines into vesicles for exocytosis. However, our knowledge of the effect of TBZ on monoaminergic transmission is limited. Herein, we provide neurochemical evidence regarding the effect of VMAT-2 inhibition on vesicular neurotransmitter release from the prefrontal cortex (PFC) and striatum (STR) (brain regions involved in characteristic TBZ treatment side effects). The interaction between TBZ and MDMA was also assessed regarding motor behaviour in mice. EXPERIMENTAL APPROACH: Vesicular storage capacity and release of [3H]-noradrenaline ([3H]-NA), [3H]-dopamine ([3H]-DA), [3H]-serotonin ([3H]-5-HT), and [3H]-acetylcholine ([3H]-ACh) was studied in mouse PFC and STR ex vivo slice preparations using electrical field stimulation. Additionally, locomotor activity was assessed in vehicle-treated mice and compared with that of MDMA, TBZ, and co-administered animals (n = 6) using the LABORAS system. KEY RESULTS: TBZ lowered the storage capacity and inhibited the vesicular release of [3H]-NA and [3H]-DA from the PFC, and [3H]-DA and [3H]-5-HT from the STR in a concentration-dependent manner. Unlike vesamicol (vesicular ACh uptake inhibitor), TBZ failed to inhibit the vesicular release of [3H]-ACh from the PFC. When the vesicular storage of the investigated monoamines was inhibited by TBZ in the PFC and STR, MDMA induced the release of transmitters through transporter reversal; MDMA dose dependently increased locomotor activity in vivo. CONCLUSION AND IMPLICATIONS: Our observations provide neurochemical evidence explaining the mechanism of VMAT-2 inhibitors in the brain and support the involvement of dopaminergic and noradrenergic transmission in hyperkinetic movement disorders.

Altered copper transport in oxidative stress-dependent brain endothelial barrier dysfunction associated with Alzheimer's disease.

Oxidative stress and blood-brain barrier (BBB) disruption due to brain endothelial barrier dysfunction contribute to Alzheimer's Disease (AD), which is characterized by beta-amyloid (Aß) accumulation in senile plaques. Copper (Cu) is implicated in AD pathology and its levels are tightly controlled by several Cu transport proteins. However, their expression and role in AD, particularly in relation to brain endothelial barrier function remains unclear. In this study, we examined the expression of Cu transport proteins in the brains of AD mouse models as well as their involvement in Aß42-induced brain endothelial barrier dysfunction. We found that the Cu uptake transporter CTR1 was upregulated, while the Cu exporter ATP7A was downregulated in the hippocampus of AD mouse models and in Aß42-treated human brain microvascular endothelial cells (hBMECs). In the 5xFAD AD mouse model, Cu levels (assessed by ICP-MS) were elevated in the hippocampus. Moreover, in cultured hBMECs, Aß42-induced reactive oxygen species (ROS) production, ROS-dependent loss in barrier function (measured by transendothelial electrical resistance), and tyrosine phosphorylation of CDH5 were all inhibited by either a membrane permeable Cu chelator or by knocking down CTR1 expression. These findings suggest that dysregulated expression of Cu transport proteins may lead to intracellular Cu accumulation in the AD brain, and that Aß42 promotes ROS-dependent brain endothelial barrier dysfunction and CDH5 phosphorylation in a CTR1-Cu-dependent manner. Our study uncovers the critical role of Cu transport proteins in oxidative stress-related loss of BBB integrity in AD.

Association between 5-HT1A receptor C-1019G, 5-HTTLPR polymorphisms and panic disorder: a meta-analysis.

HTR1A C-1019G polymorphism (rs6295) and serotonin transporter promoter polymorphism (5-HTTLPR) have been linked with panic disorder (PD) in different ethnic backgrounds. Both these polymorphisms are in the promoter regions. However, results are inconsistent and contrasting evidence makes reliable conclusions even more challenging. A meta-analysis was conducted to test whether C-1019G polymorphism and 5-HTTLPR were involved in the etiology of PD. Articles researching the link between C-1019G, 5-HTTLPR polymorphisms, and PD were retrieved by database searching and systematically selected on the basis of selected inclusion parameters. 21 studies were included that examined the relationship of rs6295,5-HTTLPR polymorphisms with PD risk susceptibility (rs62957 polymorphism - 7 articles, and 5-HTTLPR polymorphism - 14 articles). A significant association was seen between the rs6295 polymorphism and PD pathogenesis, especially in Caucasian PD patients. No significant genetic linkage was found between the 5-HTTLPR polymorphism and PD. C-1019G polymorphism was involved in the etiology of PD in Caucasian patients. The 5-HTTLPR polymorphism was not a susceptibility factor of PD.

Coenzyme A biosynthesis in Bacillus subtilis: discovery of a novel precursor metabolite for salvage and its uptake system.

The Gram-positive model bacterium Bacillus subtilis is used for many biotechnological applications, including the large-scale production of vitamins. For vitamin B5, a precursor for coenzyme A synthesis, there is so far no established fermentation process available, and the metabolic pathways that involve this vitamin are only partially understood. In this study, we have elucidated the complete pathways for the biosynthesis of pantothenate and coenzyme A in B. subtilis. Pantothenate can not only be synthesized but also be taken up from the medium. We have identified the enzymes and the transporter involved in the pantothenate biosynthesis and uptake. High-affinity vitamin B5 uptake in B. subtilis requires an ATP-driven energy coupling factor transporter with PanU (previously YhfU) as the substrate-specific subunit. Moreover, we have identified a salvage pathway for coenzyme A acquisition that acts on complex medium even in the absence of pantothenate synthesis. This pathway requires rewiring of sulfur metabolism resulting in the increased expression of a cysteine transporter. In the salvage pathway, the bacteria import cysteinopantetheine, a novel naturally occurring metabolite, using the cystine transport system TcyJKLMN. This work lays the foundation for the development of effective processes for vitamin B5 and coenzyme A production using B. subtilis. IMPORTANCE: Vitamins are essential components of the diet of animals and humans. Vitamins are thus important targets for biotechnological production. While efficient fermentation processes have been developed for several vitamins, this is not the case for vitamin B5 (pantothenate), the precursor of coenzyme A. We have elucidated the complete pathway for coenzyme A biosynthesis in the biotechnological workhorse Bacillus subtilis. Moreover, a salvage pathway for coenzyme A synthesis was found in this study. Normally, this pathway depends on pantetheine; however, we observed activity of the salvage pathway on complex medium in mutants lacking the pantothenate biosynthesis pathway even in the absence of supplemented pantetheine. This required rewiring of metabolism by expressing a cystine transporter due to acquisition of mutations affecting the regulation of cysteine metabolism. This shows how the hidden "underground metabolism" can give rise to the rapid formation of novel metabolic pathways.

Establishment of a prognostic model for pancreatic cancer based on vesicle-mediated transport protein-related genes.

This study attempted to build a prognostic riskscore model for pancreatic cancer (PC) patients based on vesicle-mediated transport protein-related genes (VMTGs). We initially conducted differential expression analysis and Cox regression analysis, followed by the construction of a riskscore model to classify PC patients into high-risk (HR) and low-risk (LR) groups. The GEO GSE62452 dataset further validated the model. Kaplan-Meier survival analysis was employed to analyze the survival rate of the HR group and LR group. Cox analysis confirmed the independent prognostic ability of the riskscore model. Additionally, we evaluated immune status in both HR and LR groups, utilizing data from the GDSC database to predict drug response among PC patients. We identified six PC-specific genes from 724 VMTGs. Survival analysis revealed that the survival rate of the HR group was lower than that of the LR group (P<0.05). Cox analysis confirmed that the prognostic riskscore model could independently predict the survival status of PC patients (P<0.001). Immunological analysis revealed that the ESTIMATE score, immune score, and stroma score of the HR group were considerably lower than those of the LR group, and the tumor purity score of the HR group was higher. The IC50 values of Gemcitabine, Irinotecan, Oxaliplatin, and Paclitaxel in the LR group were considerably lower than those in the HR group (P<0.001). In summary, the VMTG-based prognostic riskscore model could stratify PC risk and effectively predict the survival of PC patients.

Enterocyte-specific FATP4 deficiency elevates blood lipids via a shift from polar to neutral lipids in distal intestine.

Fatty acid transport protein (FATP)4 was thought to mediate intestinal lipid absorption, which was disputed by a study using keratinocyte-Fatp4-rescued Fatp4-/- mice. These knockouts when fed with a Western diet showed elevated intestinal triglyceride (TG) and fatty acid levels. To investigate a possible role of FATP4 on intestinal lipid processing, ent-Fatp4 (KO) mice were generated by Villin-Cre-specific inactivation of the Fatp4 gene. We aimed to measure circulating and intestinal lipids in control and KO mice after acute or chronic fat intake or during aging. Remarkably, ent-Fatp4 mice displayed an approximately 30% decrease in ileal behenic, lignoceric, and nervonic acids, ceramides containing these FA, as well as, ileal sphingomyelin, phosphatidylcholine, and phosphatidylinositol levels. Such decreases were concomitant with an increase in jejunal cholesterol ester. After a 2-wk recovery from high lipid overload by tyloxapol and oral-lipid treatment, ent-Fatp4 mice showed an increase in plasma TG and chylomicrons. Upon overnight fasting followed by an oral fat meal, ent-Fatp4 mice showed an increase in plasma TG-rich lipoproteins and the particle number of chylomicrons and very low-density lipoproteins. During aging or after feeding with a high-fat high-cholesterol (HFHC) diet, ent-Fatp4 mice showed an increase in plasma TG, fatty acids, glycerol, and lipoproteins as well as intestinal lipids. HFHC-fed KO mice displayed an increase in body weight, the number of lipid droplets with larger sizes in the ileum, concomitant with a decrease in ileal ceramides and phosphatidylcholine. Thus, enterocyte FATP4 deficiency led to a metabolic shift from polar to neutral lipids in distal intestine rendering an increase in plasma lipids and lipoproteins.NEW & NOTEWORTHY Enterocyte-specific Fatp4 deficiency in mice increased intestinal lipid absorption with elevation of blood lipids during fasting and aging, as well as after an acute oral fat-loading or chronic HFHC feeding. Lipidomics revealed that knockout mice displayed a shift from very long-chain to long-chain fatty acids, and from polar to neutral lipids, predominantly in the ileum. Thus, FATP4 may have a physiological function in the control of blood lipids via metabolic shifts in distal intestine.

Randomized Evaluation of a Remote Management Program to Improve Guideline-Directed Medical Therapy: The DRIVE Trial.

BACKGROUND: Several SGLT2i (sodium-glucose transport protein 2 inhibitors) and GLP1-RA (glucagon-like peptide-1 receptor agonists) reduce cardiovascular events and improve kidney outcomes in patients with type 2 diabetes; however, utilization remains low despite guideline recommendations. METHODS: A randomized, remote implementation trial in the Mass General Brigham network enrolled patients with type 2 diabetes with increased cardiovascular or kidney risk. Patients eligible for, but not prescribed, SGLT2i or GLP1-RA were randomly assigned to simultaneous virtual patient education with concurrent prescription of SGLT2i or GLP1-RA (ie, Simultaneous) or 2 months of virtual education followed by medication prescription (ie, Education-First) delivered by a multidisciplinary team driven by nonlicensed navigators and clinical pharmacists who prescribed SGLT2i or GLP1-RA using a standardized treatment algorithm. The primary outcome was the proportion of patients with prescriptions for either SGLT2i or GLP1-RA by 6 months. RESULTS: Between March 2021 and December 2022, 200 patients were randomized. The mean age was 66.5 years; 36.5% were female, and 22.0% were non-White. Overall, 30.0% had cardiovascular disease, 5.0% had cerebrovascular disease, and 1.5% had both. Mean estimated glomerular filtration rate was 77.9 mL/(min‧1.73 m2), and mean urine/albumin creatinine ratio was 88.6 mg/g. After 2 months, 69 of 200 (34.5%) patients received a new prescription for either SGLT2i or GLP1-RA: 53.4% of patients in the Simultaneous arm and 8.3% of patients in the Education-First arm (P<0.001). After 6 months, 128 of 200 (64.0%) received a new prescription: 69.8% of patients in the Simultaneous arm and 56.0% of patients in Education-First (P<0.001). Patient self-report of taking SGLT2i or GLP1-RA within 6 months of trial entry was similarly greater in the Simultaneous versus Education-First arm (69 of 116 [59.5%] versus 37 of 84 [44.0%]; P<0.001) Median time to first prescription was 24 (interquartile range [IQR], 13-50) versus 85 days (IQR, 65-106), respectively (P<0.001). CONCLUSIONS: In this randomized trial, a remote, team-based program identifies patients with type 2 diabetes and high cardiovascular or kidney risk, provides virtual education, prescribes SGLT2i or GLP1-RA, and improves guideline-directed medical therapy. These findings support greater utilization of virtual team-based approaches to optimize chronic disease management. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT06046560.

Structure, Functions, and Implications of Selected Lipocalins in Human Disease.

The lipocalin proteins are a large family of small extracellular proteins that demonstrate significant heterogeneity in sequence similarity and have highly conserved crystal structures. They have a variety of functions, including acting as carrier proteins, transporting retinol, participating in olfaction, and synthesizing prostaglandins. Importantly, they also play a critical role in human diseases, including cancer. Additionally, they are involved in regulating cellular homeostasis and immune response and dispensing various compounds. This comprehensive review provides information on the lipocalin family, including their structure, functions, and implications in various diseases. It focuses on selective important human lipocalin proteins, such as lipocalin 2 (LCN2), retinol binding protein 4 (RBP4), prostaglandin D2 synthase (PTGDS), and α1-microglobulin (A1M).

An Insider's Perspective about the Pathogenic Relevance of Gut Bacterial Transportomes.

BACKGROUND: The gut microbiome is integral to host health, hosting complex interactions between the host and numerous microbial species in the gastrointestinal tract. Key among the molecular mechanisms employed by gut bacteria are transportomes, consisting of diverse transport proteins crucial for bacterial adaptation to the dynamic, nutrient-rich environment of the mammalian gut. These transportomes facilitate the movement of a wide array of molecules, impacting both the host and the microbial community. SUMMARY: This communication explores the significance of transportomes in gut bacteria, focusing on their role in nutrient acquisition, competitive interactions among microbes, and potential pathogenicity. It delves into the transportomes of key gut bacterial species like E. coli, Salmonella, Bacteroides, Lactobacillus, Clostridia, and Bifidobacterium, examining the functions of predicted transport proteins. The overview synthesizes recent research efforts, highlighting how these transportomes influence host-microbe interactions and contribute to the microbial ecology of the gut. KEY MESSAGES: Transportomes are vital for the survival and adaptation of bacteria in the gut, enabling the import and export of various nutrients and molecules. The complex interplay of transport proteins not only supports bacterial growth and competition but also has implications for host health, potentially contributing to pathogenic processes. Understanding the pathogenic potential of transportomes in major gut bacterial species provides insights into gut health and disease, offering avenues for future research and therapeutic strategies.

Iron Dysregulation in Alzheimer's Disease: LA-ICP-MS Bioimaging of the Distribution of Iron and Ferroportin in the CA1 Region of the Human Hippocampus.

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by cognitive decline and neuropathological hallmarks, including ß-amyloid (Aß) plaques, Tau tangles, synaptic dysfunction and neurodegeneration. Emerging evidence suggests that abnormal iron (Fe) metabolism plays a role in AD pathogenesis, but the precise spatial distribution of the Fe and its transporters, such as ferroportin (FPN), within affected brain regions remains poorly understood. This study investigates the distribution of Fe and FPN in the CA1 region of the human hippocampus in AD patients with a micrometer lateral resolution using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). For this purpose, we visualized and quantified Fe and FPN in three separated CA1 layers: stratum molecular-radial (SMR), stratum pyramidal (SP) and stratum oriens (SO). Additionally, chromogenic immunohistochemistry was used to examine the distribution and colocalization with Tau and Aß proteins. The results show that Fe accumulation was significantly higher in AD brains, particularly in SMR and SO. However, FPN did not present significantly changes in AD, although it showed a non-uniform distribution across CA1 layers, with elevated levels in SP and SO. Interestingly, minimal overlap was observed between Fe and FPN signals, and none between Fe and areas rich in neurofibrillary tangles (NFTs) or neuritic plaques (NP). In conclusion, the lack of correlation between Fe and FPN signals suggests complex regulatory mechanisms in AD Fe metabolism and deposition. These findings highlight the complexity of Fe dysregulation in AD and its potential role in disease progression.

Imaging metabolic mechanisms and the binding behavior of nutrients/transporters of edible Matricaria flowers VOCs.

To promote the consumption of flowers and to utilize the nutritional value of proteins, the efficacy of the beneficial components of flowers has been intensively studied. Anthemis nobilis was used as the study object, and all its volatile components (VOCs) were fingerprinted using headspace solid-phase micro-extraction gas-mass spectrometry (HS-SPME/GC-MS). GC-MS fingerprints of five parts of Anthemis nobilis were established using three proteins, bovine lactoferrin (BLF), bovine lactoglobulin (ß-Lg), and human serum albumin (HSA), as nutrient transporters. The interactions between the volatile components from different parts of the mother chrysanthemum plant and the nutrient/transport proteins were investigated. The results of fingerprinting showed that the flavor components were dominated by alkenes. In addition, this study revealed that among the three nutrient transporters, the strongest binding to the adsorbed volatile components was HSA, followed by BLF, and ß-Lg was second. In addition, a characteristic molecule, camphene, was screened. Integrated molecular simulation using fluorescence spectroscopy was used to validate the results of the interaction of the nutrient/transport proteins systems with characteristic molecule. The properties of the characteristic molecules such as absorption, distribution, metabolism, excretion and toxicity in vivo were analyzed using ADMET to provide a theoretical basis for the preparation of flower-flavored dairy products.

Structural and biophysical analysis of a Haemophilus influenzae tripartite ATP-independent periplasmic (TRAP) transporter.

Tripartite ATP-independent periplasmic (TRAP) transporters are secondary-active transporters that receive their substrates via a soluble-binding protein to move bioorganic acids across bacterial or archaeal cell membranes. Recent cryo-electron microscopy (cryo-EM) structures of TRAP transporters provide a broad framework to understand how they work, but the mechanistic details of transport are not yet defined. Here we report the cryo-EM structure of the Haemophilus influenzae N-acetylneuraminate TRAP transporter (HiSiaQM) at 2.99 Å resolution (extending to 2.2 Å at the core), revealing new features. The improved resolution (the previous HiSiaQM structure is 4.7 Å resolution) permits accurate assignment of two Na+ sites and the architecture of the substrate-binding site, consistent with mutagenic and functional data. Moreover, rather than a monomer, the HiSiaQM structure is a homodimer. We observe lipids at the dimer interface, as well as a lipid trapped within the fusion that links the SiaQ and SiaM subunits. We show that the affinity (KD) for the complex between the soluble HiSiaP protein and HiSiaQM is in the micromolar range and that a related SiaP can bind HiSiaQM. This work provides key data that enhances our understanding of the 'elevator-with-an-operator' mechanism of TRAP transporters.

Microbial membrane transport proteins and their biotechnological applications.

Because of the hydrophobic nature of the membrane lipid bilayer, the majority of the hydrophilic solutes require special transportation mechanisms for passing through the cell membrane. Integral membrane transport proteins (MTPs), which belong to the Major Intrinsic Protein Family, facilitate the transport of these solutes across cell membranes. MTPs including aquaporins and carrier proteins are transmembrane proteins spanning across the cell membrane. The easy handling of microorganisms enabled the discovery of a remarkable number of transport proteins specific to different substances. It has been realized that these transporters have very important roles in the survival of microorganisms, their pathogenesis, and antimicrobial resistance. Astonishing features related to the solute specificity of these proteins have led to the acceleration of the research on the discovery of their properties and the development of innovative products in which these unique properties are used or imitated. Studies on microbial MTPs range from the discovery and characterization of a novel transporter protein to the mining and screening of them in a large transporter library for particular functions, from simulations and modeling of specific transporters to the preparation of biomimetic synthetic materials for different purposes such as biosensors or filtration membranes. This review presents recent discoveries on microbial membrane transport proteins and focuses especially on formate nitrite transport proteins and aquaporins, and advances in their biotechnological applications.

Therapeutic targeting of nuclear export and import receptors in cancer and their potential in combination chemotherapy.

Systemic modalities are crucial in the management of disseminated malignancies and liquid tumours. However, patient responses and tolerability to treatment are generally poor and those that enter remission often return with refractory disease. Combination therapies provide a methodology to overcome chemoresistance mechanisms and address dose-limiting toxicities. A deeper understanding of tumorigenic processes at the molecular level has brought a targeted therapy approach to the forefront of cancer research, and novel cancer biomarkers are being identified at a rapid rate, with some showing potential therapeutic benefits. The Karyopherin superfamily of proteins is soluble receptors that mediate nucleocytoplasmic shuttling of proteins and RNAs, and recently, nuclear transport receptors have been recognized as novel anticancer targets. Inhibitors against nuclear export have been approved for clinical use against certain cancer types, whereas inhibitors against nuclear import are in preclinical stages of investigation. Mechanistically, targeting nucleocytoplasmic shuttling has shown to abrogate oncogenic signalling and restore tumour suppressor functions through nuclear sequestration of relevant proteins and mRNAs. Hence, nuclear transport inhibitors display broad spectrum anticancer activity and harbour potential to engage in synergistic interactions with a wide array of cytotoxic agents and other targeted agents. This review is focussed on the most researched nuclear transport receptors in the context of cancer, XPO1 and KPNB1, and highlights how inhibitors targeting these receptors can enhance the therapeutic efficacy of standard of care therapies and novel targeted agents in a combination therapy approach. Furthermore, an updated review on the therapeutic targeting of lesser characterized karyopherin proteins is provided and resistance to clinically approved nuclear export inhibitors is discussed.

Effect of sevoflurane on Ca 2+ transporter expression in cardiomyocytes during right ventricular remodeling in rats with pulmonary arterial hypertension / 中华麻醉学杂志

Objective:To evaluate the effect of sevoflurane on Ca 2+ transporter expression in cardiomyocytes during right ventricular remodeling in rats with pulmonary arterial hypertension. Methods:Twenty-four clean-grade healthy male Sprague-Dawley rats, aged 8-10 weeks, weighing 200-250 g, were divided into 4 groups ( n=6 each) by the random number table method: control group (CM group), sevoflurane group (CS group), monocrotaline group (M group) and sevoflurane + monocrotaline group (S group). Monocrotaline 60 mg/kg was intraperitoneally injected in group M and group S, and monocrotaline lysate was intraperitoneally injected in group CM. The rats in S and CS groups inhaled 2.5% sevoflurane for 1 h, twice a week, at an interval of 3 days starting from the first day after injection of monocrotaline. Pulmonary artery acceleration time and pulmonary artery ejection time were measured by transthoracic echocardiography at 6 weeks after monocrotaline injection. The chest was exposed under 3% sevoflurane anesthesia, the heart was perfused, and the pulmonary artery branch and right ventricular myocardial tissues were retained. The wall thickness of pulmonary arterioles and cross-section area of right ventricular cardiomyocytes were observed by HE staining. The expression of Ca 2+ transporter in right ventricular cardiomyocytes was detected by Western blot. Results:Compared with CM group, the ratio of pulmonary artery acceleration time to pulmonary artery ejection time was significantly decreased, the cross-section area of right ventricular cardiomyocytes was increased, the wall thickness of pulmonary arteriole was increased, the expression of type 1 sodium-calcium exchange and inositol triphosphate receptor was up-regulated, and the expression of voltage-dependent L-type calcium channel α1C subunit, type 2 ryanodine receptor, sarcoplasmic reticulum calcium pump 2α and proteinphilin-2 was down-regulated in M group ( P<0.01). Compared with group M, the ratio of pulmonary artery acceleration time to pulmonary artery ejection time was significantly increased, the cross-section area of right ventricular cardiomyocytes was decreased, the wall thickness of pulmonary arteriole was decreased, the expression of type 1 sodium-calcium exchange and inositol triphosphate receptor was down-regulated, and the expression of voltage-dependent L-type calcium channel α1C subunit, type 2 ryanodine receptor, sarcoplasmic reticulum calcium pump 2α and proteinphilin-2 was up-regulated in group S ( P<0.01). Conclusions:The mechanism by which sevoflurane improves right ventricular remodeling is related to regulating the expression of Ca 2+ transporter in cardiomyocytes of rats with pulmonary arterial hypertension.

CNS Drug Delivery in Stroke: Improving Therapeutic Translation From the Bench to the Bedside.

Drug development for ischemic stroke is challenging as evidenced by the paucity of therapeutics that have advanced beyond a phase III trial. There are many reasons for this lack of clinical translation including factors related to the experimental design of preclinical studies. Often overlooked in therapeutic development for ischemic stroke is the requirement of effective drug delivery to the brain, which is critical for neuroprotective efficacy of several small and large molecule drugs. Advancing central nervous system drug delivery technologies implies a need for detailed comprehension of the blood-brain barrier (BBB) and neurovascular unit. Such knowledge will permit the innate biology of the BBB/neurovascular unit to be leveraged for improved bench-to-bedside translation of novel stroke therapeutics. In this review, we will highlight key aspects of BBB/neurovascular unit pathophysiology and describe state-of-the-art approaches for optimization of central nervous system drug delivery (ie, passive diffusion, mechanical opening of the BBB, liposomes/nanoparticles, transcytosis, intranasal drug administration). Additionally, we will discuss how endogenous BBB transporters represent the next frontier of drug delivery strategies for stroke. Overall, this review will provide cutting edge perspective on how central nervous system drug delivery must be considered for the advancement of new stroke drugs toward human trials.

Transport proteins and their differential roles in the accumulation of phenanthrene in wheat.

The study focuses on the uptake, accumulation, and translocation of polycyclic aromatic hydrocarbons (PAHs) in cereals, specifically exploring the role of peroxidase (UniProt accession: A0A3B5XXD0, abbreviation: PX1) and unidentified protein (UniProt accession: A0A3B6LUC6, abbreviation: UP1) in phenanthrene solubilization within wheat xylem sap. This research aims to clarify the interactions between these proteins and phenanthrene. Employing both in vitro and in vivo analyses, we evaluated the solubilization capabilities of recombinant transport proteins for phenanthrene and examined the relationship between protein expression and phenanthrene concentration. UP1 displayed greater transport efficiency, while PX1 excelled at lower concentrations. Elevated PX1 levels contributed to phenanthrene degradation, marginally diminishing its transport. Spectral analyses and molecular dynamics simulations validated the formation of stable protein-phenanthrene complexes. The study offers crucial insights into PAH-related health risks in crops by elucidating the mechanisms of PAH accumulation facilitated by transport proteins.

Screening of Saccharomyces cerevisiae metabolite transporters by 13C isotope substrate labeling.

The transportome of Saccharomyces cerevisiae comprises approximately 340 membrane-bound proteins, of which very few are well-characterized. Elucidating transporter proteins' function is essential not only for understanding central cellular processes in metabolite exchange with the external milieu but also for optimizing the production of value-added compounds in microbial cell factories. Here, we describe the application of 13C-labeled stable isotopes and detection by targeted LC-MS/MS as a screening tool for identifying Saccharomyces cerevisiae metabolite transporters. We compare the transport assay's sensitivity, reproducibility, and accuracy in yeast transporter mutant cell lines and Xenopus oocytes. As proof of principle, we analyzed the transport profiles of five yeast amino acid transporters. We first cultured yeast transporter deletion or overexpression mutants on uniformly labeled 13C-glucose and then screened their ability to facilitate the uptake or export of an unlabeled pool of amino acids. Individual transporters were further studied by heterologous expression in Xenopus oocytes, followed by an uptake assay with 13C labeled yeast extract. Uptake assays in Xenopus oocytes showed higher reproducibility and accuracy. Although having lower accuracy, the results from S. cerevisiae indicated the system's potential for initial high-throughput screening for native metabolite transporters. We partially confirmed previously reported substrates for all five amino acid transporters. In addition, we propose broader substrate specificity for two of the transporter proteins. The method presented here demonstrates the application of a comprehensive screening platform for the knowledge expansion of the transporter-substrate relationship for native metabolites in S. cerevisiae.

FATP4 deletion in liver cells induces elevation of extracellular lipids via metabolic channeling towards triglycerides and lipolysis.

Evidence from mice with global deletion of fatty-acid transport protein4 (FATP4) indicates its role on ß-oxidation and triglycerides (TG) metabolism. We reported that plasma glycerol and free fatty acids (FA) were increased in liver-specific Fatp4 deficient (L-FATP4-/-) mice under dietary stress. We hypothesized that FATP4 may mediate hepatocellular TG lipolysis. Here, we demonstrated that L-FATP4-/- mice showed an increase in these blood lipids, liver TG, and subcutaneous fat weights. We therefore studied TG metabolism in response to oleate treatment in two experimental models using FATP4-knockout HepG2 (HepKO) cells and L-FATP4-/- hepatocytes. Both FATP4-deificient liver cells showed a significant decrease in ß-oxidation products by ∼30-35% concomitant with marked upregulation of CD36, FATP2, and FATP5 as well as lipoprotein microsomal-triglyceride-transfer protein genes. By using 13C3D5-glycerol, HepKO cells displayed an increase in metabolically labelled TG species which were further increased with oleate treatment. This increase was concomitant with a step-wise elevation of TG in cells and supernatants as well as the secretion of cholesterol very low-density and high-density lipoproteins. Upon analyzing TG lipolytic enzymes, both mutant liver cells showed marked upregulated expression of hepatic lipase, while that of hormone-sensitive lipase and adipose-triglyceride lipase was downregulated. Lipolysis measured by extracellular glycerol and free FA was indeed increased in mutant cells, and this event was exacerbated by oleate treatment. Taken together, FATP4 deficiency in liver cells led to a metabolic shift from ß-oxidation towards lipolysis-directed TG and lipoprotein secretion, which is in line with an association of FATP4 polymorphisms with blood lipids.

Internalization and trafficking of zinc transporters.

In huma, two transporter families, the zinc transporters (ZNT/solute carrier 30 family [SLC30A]) and the Zrt- and Irt-like proteins (ZIP/solute carrier 39 family [SLC39A]), play vital roles in maintaining zinc homeostasis. ZIPs could increase the concentration of cytosolic Zn2+ by importing zinc from the extracellular environment or organelles into the cytosol, while ZnTs work in the opposite direction as they mediate the export of zinc from the cytosol into organelles or out of the cells. Mammalian cells express 10 ZnT exporters and 14 ZIP importers, and zinc or other transition metal ions may modulate their gene expression. The localization and post-translational trafficking of zinc transporters within the cells are often controlled in response to varying zinc concentrations, which likely impact the regulation of cellular zinc homeostasis. This chapter briefly summarizes the progress made on the intracellular trafficking of ZIPs and outlines the protocols used to study the endocytosis and trafficking of a representative human zinc transporter, ZIP4.