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1.
World J Gastroenterol ; 30(19): 2575-2602, 2024 May 21.
Article En | MEDLINE | ID: mdl-38817665

BACKGROUND: Lactate, previously considered a metabolic byproduct, is pivotal in cancer progression and maintaining the immunosuppressive tumor microenvironment. Further investigations confirmed that lactate is a primary regulator, introducing recently described post-translational modifications of histone and non-histone proteins, termed lysine lactylation. Pancreatic adenocarcinomas are characterized by increased glycolysis and lactate accumulation. However, our understanding of lactylation-related genes in pancreatic adenocarcinomas remains limited. AIM: To construct a novel lactylation-related gene signature to predict the survival of patients with pancreatic cancer. METHODS: RNA-seq and clinical data of pancreatic adenocarcinoma (PDAC) were obtained from the GTEx (Genotype-Tissue Expression) and TCGA (The Cancer Genome Atlas) databases via Xena Explorer, and GSE62452 datasets from GEO. Data on lactylation-related genes were obtained from publicly available sources. Differential expressed genes (DEGs) were acquired by using R package "DESeq2" in R. Univariate COX regression analysis, LASSO Cox and multivariate Cox regressions were produced to construct the lactylation-related prognostic model. Further analyses, including functional enrichment, ESTIMATE, and CIBERSORT, were performed to analyze immune status and treatment responses in patients with pancreatic cancer. PDAC and normal human cell lines were subjected to western blot analysis under lactic acid intervention; two PDAC cell lines with the most pronounced lactylation were selected. Subsequently, RT-PCR was employed to assess the expression of LRGs genes; SLC16A1, which showed the highest expression, was selected for further investigation. SLC16A1-mediated lactylation was analyzed by immunofluorescence, lactate production analysis, colony formation, transwell, and wound healing assays to investigate its role in promoting the proliferation and migration of PDAC cells. In vivo validation was performed using an established tumor model. RESULTS: In this study, we successfully identified 10 differentially expressed lactylation-related genes (LRGs) with prognostic value. Subsequently, a lactylation-related signature was developed based on five OS-related lactylation-related genes (SLC16A1, HLA-DRB1, KCNN4, KIF23, and HPDL) using Lasso Cox hazard regression analysis. Subsequently, we evaluated the clinical significance of the lactylation-related genes in pancreatic adenocarcinoma. A comprehensive examination of infiltrating immune cells and tumor mutation burden was conducted across different subgroups. Furthermore, we demonstrated that SLC16A1 modulates lactylation in pancreatic cancer cells through lactate transport. Both in vivo and in vitro experiments showed that decreasing SLC16A1 Level and its lactylation significantly inhibited tumor progression, indicating the potential of targeting the SLC16A1/Lactylation-associated signaling pathway as a therapeutic strategy against pancreatic adenocarcinoma. CONCLUSION: We constructed a novel lactylation-related prognostic signature to predict OS, immune status, and treatment response of patients with pancreatic adenocarcinoma, providing new strategic directions and antitumor immunotherapies.


Gene Expression Regulation, Neoplastic , Pancreatic Neoplasms , Tumor Microenvironment , Humans , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Pancreatic Neoplasms/mortality , Pancreatic Neoplasms/immunology , Pancreatic Neoplasms/metabolism , Prognosis , Cell Line, Tumor , Tumor Microenvironment/immunology , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Monocarboxylic Acid Transporters/genetics , Monocarboxylic Acid Transporters/metabolism , Protein Processing, Post-Translational , Adenocarcinoma/genetics , Adenocarcinoma/pathology , Adenocarcinoma/mortality , Adenocarcinoma/immunology , Adenocarcinoma/metabolism , Lactic Acid/metabolism , Symporters/genetics , Symporters/metabolism , Cell Proliferation/genetics , Gene Expression Profiling , Male , Carcinoma, Pancreatic Ductal/genetics , Carcinoma, Pancreatic Ductal/mortality , Carcinoma, Pancreatic Ductal/pathology , Carcinoma, Pancreatic Ductal/immunology , Carcinoma, Pancreatic Ductal/therapy , Female , Animals , Transcriptome
2.
J Cell Mol Med ; 28(10): e18409, 2024 May.
Article En | MEDLINE | ID: mdl-38769917

Farnesoid X receptor (FXR), a ligand-activated transcription factor, plays an important role in maintaining water homeostasis by up-regulating aquaporin 2 (AQP2) expression in renal medullary collecting ducts; however, its role in the survival of renal medullary interstitial cells (RMICs) under hypertonic conditions remains unclear. We cultured primary mouse RMICs and found that the FXR was expressed constitutively in RMICs, and that its expression was significantly up-regulated at both mRNA and protein levels by hypertonic stress. Using luciferase and ChIP assays, we found a potential binding site of nuclear factor kappa-B (NF-κB) located in the FXR gene promoter which can be bound and activated by NF-κB. Moreover, hypertonic stress-induced cell death in RMICs was significantly attenuated by FXR activation but worsened by FXR inhibition. Furthermore, FXR increased the expression and nuclear translocation of hypertonicity-induced tonicity-responsive enhance-binding protein (TonEBP), the expressions of its downstream target gene sodium myo-inositol transporter (SMIT), and heat shock protein 70 (HSP70). The present study demonstrates that the NF-κB/FXR/TonEBP pathway protects RMICs against hypertonic stress.


Kidney Medulla , NF-kappa B , Signal Transduction , Animals , NF-kappa B/metabolism , Mice , Kidney Medulla/metabolism , Kidney Medulla/cytology , Osmotic Pressure , Aquaporin 2/metabolism , Aquaporin 2/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Male , Mice, Inbred C57BL , HSP70 Heat-Shock Proteins/metabolism , HSP70 Heat-Shock Proteins/genetics , Promoter Regions, Genetic , Cells, Cultured , Gene Expression Regulation , Symporters/metabolism , Symporters/genetics , Receptors, Cytoplasmic and Nuclear
3.
Nat Commun ; 15(1): 4386, 2024 May 23.
Article En | MEDLINE | ID: mdl-38782953

Sialin, a member of the solute carrier 17 (SLC17) transporter family, is unique in its ability to transport not only sialic acid using a pH-driven mechanism, but also transport mono and diacidic neurotransmitters, such as glutamate and N-acetylaspartylglutamate (NAAG), into synaptic vesicles via a membrane potential-driven mechanism. While most transporters utilize one of these mechanisms, the structural basis of how Sialin transports substrates using both remains unclear. Here, we present the cryogenic electron-microscopy structures of human Sialin: apo cytosol-open, apo lumen-open, NAAG-bound, and inhibitor-bound. Our structures show that a positively charged cytosol-open vestibule accommodates either NAAG or the Sialin inhibitor Fmoc-Leu-OH, while its luminal cavity potentially binds sialic acid. Moreover, functional analyses along with molecular dynamics simulations identify key residues in binding sialic acid and NAAG. Thus, our findings uncover the essential conformational states in NAAG and sialic acid transport, demonstrating a working model of SLC17 transporters.


Cryoelectron Microscopy , Molecular Dynamics Simulation , Humans , N-Acetylneuraminic Acid/metabolism , N-Acetylneuraminic Acid/chemistry , Lysosomes/metabolism , HEK293 Cells , Protein Conformation , Organic Anion Transporters/metabolism , Organic Anion Transporters/chemistry , Organic Anion Transporters/antagonists & inhibitors , Dipeptides/chemistry , Dipeptides/metabolism , Dipeptides/pharmacology , Symporters
4.
Sci Rep ; 14(1): 10689, 2024 05 09.
Article En | MEDLINE | ID: mdl-38724641

Homeostatic plasticity, the ability of neurons to maintain their averaged activity constant around a set point value, is thought to account for the central hyperactivity after hearing loss. Here, we investigated the putative role of GABAergic neurotransmission in this mechanism after a noise-induced hearing loss larger than 50 dB in high frequencies in guinea pigs. The effect of GABAergic inhibition is linked to the normal functioning of K + -Cl- co-transporter isoform 2 (KCC2) which maintains a low intracellular concentration of chloride. The expression of membrane KCC2 were investigated before and after noise trauma in the ventral and dorsal cochlear nucleus (VCN and DCN, respectively) and in the inferior colliculus (IC). Moreover, the effect of gabazine (GBZ), a GABA antagonist, was also studied on the neural activity in IC. We show that KCC2 is downregulated in VCN, DCN and IC 3 days after noise trauma, and in DCN and IC 30 days after the trauma. As expected, GBZ application in the IC of control animals resulted in an increase of spontaneous and stimulus-evoked activity. In the noise exposed animals, on the other hand, GBZ application decreased the stimulus-evoked activity in IC neurons. The functional implications of these central changes are discussed.


Hearing Loss, Noise-Induced , K Cl- Cotransporters , Symporters , gamma-Aminobutyric Acid , Animals , Symporters/metabolism , Symporters/antagonists & inhibitors , Guinea Pigs , Hearing Loss, Noise-Induced/metabolism , Hearing Loss, Noise-Induced/physiopathology , gamma-Aminobutyric Acid/metabolism , Male , Cochlear Nucleus/metabolism , Pyridazines/pharmacology , Neurons/metabolism
5.
Cancer J ; 30(3): 194-201, 2024.
Article En | MEDLINE | ID: mdl-38753754

ABSTRACT: Differentiated thyroid carcinoma (DTC) has been increasing in incidence in the United States over the last several decades, although mortality rates have remained low. Radioactive iodine therapy (RAI-T) has been a mainstay of treatment for DTC since the 1940s. Imaging of DTC before and after RAI-T primarily focuses on molecular imaging of the sodium iodide symporter. The expanding understanding of the molecular profile of DTC has increased available treatment options. Incorporation of risk stratification to treatment approaches has led to deintensification of both surgical and nonsurgical treatments, leading to decreased morbidity without compromising disease control.


Iodine Radioisotopes , Molecular Imaging , Thyroid Neoplasms , Humans , Thyroid Neoplasms/therapy , Thyroid Neoplasms/diagnosis , Thyroid Neoplasms/pathology , Thyroid Neoplasms/diagnostic imaging , Molecular Imaging/methods , Iodine Radioisotopes/therapeutic use , Adult , Symporters/genetics , Symporters/metabolism
6.
Cell Mol Life Sci ; 81(1): 206, 2024 May 06.
Article En | MEDLINE | ID: mdl-38709307

The epithelial-mesenchymal transformation (EMT) process of alveolar epithelial cells is recognized as involved in the development of pulmonary fibrosis. Recent evidence has shown that lipopolysaccharide (LPS)-induced aerobic glycolysis of lung tissue and elevated lactate concentration are associated with the pathogenesis of sepsis-associated pulmonary fibrosis. However, it is uncertain whether LPS promotes the development of sepsis-associated pulmonary fibrosis by promoting lactate accumulation in lung tissue, thereby initiating EMT process. We hypothesized that monocarboxylate transporter-1 (MCT1), as the main protein for lactate transport, may be crucial in the pathogenic process of sepsis-associated pulmonary fibrosis. We found that high concentrations of lactate induced EMT while moderate concentrations did not. Besides, we demonstrated that MCT1 inhibition enhanced EMT process in MLE-12 cells, while MCT1 upregulation could reverse lactate-induced EMT. LPS could promote EMT in MLE-12 cells through MCT1 inhibition and lactate accumulation, while this could be alleviated by upregulating the expression of MCT1. In addition, the overexpression of MCT1 prevented LPS-induced EMT and pulmonary fibrosis in vivo. Altogether, this study revealed that LPS could inhibit the expression of MCT1 in mouse alveolar epithelial cells and cause lactate transport disorder, which leads to lactate accumulation, and ultimately promotes the process of EMT and lung fibrosis.


Epithelial-Mesenchymal Transition , Lactic Acid , Lipopolysaccharides , Monocarboxylic Acid Transporters , Pulmonary Fibrosis , Symporters , Monocarboxylic Acid Transporters/metabolism , Monocarboxylic Acid Transporters/genetics , Monocarboxylic Acid Transporters/antagonists & inhibitors , Animals , Epithelial-Mesenchymal Transition/drug effects , Lipopolysaccharides/pharmacology , Symporters/metabolism , Symporters/genetics , Symporters/antagonists & inhibitors , Mice , Lactic Acid/metabolism , Pulmonary Fibrosis/metabolism , Pulmonary Fibrosis/pathology , Pulmonary Fibrosis/chemically induced , Mice, Inbred C57BL , Cell Line , Male , Alveolar Epithelial Cells/metabolism , Alveolar Epithelial Cells/pathology , Alveolar Epithelial Cells/drug effects , Up-Regulation/drug effects
7.
J Neurosci Res ; 102(5): e25355, 2024 May.
Article En | MEDLINE | ID: mdl-38808645

Gamma aminobutyric acid (GABA) is a critical inhibitory neurotransmitter in the central nervous system that plays a vital role in modulating neuronal excitability. Dysregulation of GABAergic signaling, particularly involving the cotransporters NKCC1 and KCC2, has been implicated in various pathologies, including epilepsy, schizophrenia, autism spectrum disorder, Down syndrome, and ischemia. NKCC1 facilitates chloride influx, whereas KCC2 mediates chloride efflux via potassium gradient. Altered expression and function of these cotransporters have been associated with excitotoxicity, inflammation, and cellular death in ischemic events characterized by reduced cerebral blood flow, leading to compromised tissue metabolism and subsequent cell death. NKCC1 inhibition has emerged as a potential therapeutic approach to attenuate intracellular chloride accumulation and mitigate neuronal damage during ischemic events. Similarly, targeting KCC2, which regulates chloride efflux, holds promise for improving outcomes and reducing neuronal damage under ischemic conditions. This review emphasizes the critical roles of GABA, NKCC1, and KCC2 in ischemic pathologies and their potential as therapeutic targets. Inhibiting or modulating the activity of these cotransporters represents a promising strategy for reducing neuronal damage, preventing excitotoxicity, and improving neurological outcomes following ischemic events. Furthermore, exploring the interactions between natural compounds and NKCC1/KCC2 provides additional avenues for potential therapeutic interventions for ischemic injury.


Brain Ischemia , Cell Death , K Cl- Cotransporters , Solute Carrier Family 12, Member 2 , Symporters , gamma-Aminobutyric Acid , Animals , Humans , gamma-Aminobutyric Acid/metabolism , Symporters/metabolism , Solute Carrier Family 12, Member 2/metabolism , Cell Death/physiology , Cell Death/drug effects , Brain Ischemia/metabolism , Brain Ischemia/drug therapy
8.
Biochim Biophys Acta Mol Cell Res ; 1871(5): 119740, 2024 Jun.
Article En | MEDLINE | ID: mdl-38697303

γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system. The termination of GABA transmission is through the action of GABA transporters (GATs). mGAT4 (encoded by Slc6a11) is another GAT besides GAT1 (encoded by Slc6a1) that functions in GABA reuptake in CNS. Research on the function of mGAT4 is still in its infancy. We developed an mGat4 knockout mouse model (mGat4-/- mice) and performed a series of behavioral analyses for the first time to study the effect of mGat4 on biological processes in CNS. Our results indicated that homozygous mGat4-/- mice had less depression, anxiety-like behavior and more social activities than their wild-type littermate controls. However, they had weight loss and showed motor incoordination and imbalance. Meanwhile, mGat4-/- mice showed increased pain threshold and hypoalgesia behavior in nociceptive stimulus and learning and memory impairments. The expression of multiple components of the GABAergic system including GAD67, GABAA and KCC2 was altered. There is little or no compensatory change in mGat1. In a word, mGat4 may play a key role in normal motor coordination, sensation, emotion, learning and memory and could be the potential target of neurological disorders.


GABA Plasma Membrane Transport Proteins , Mice, Knockout , Animals , GABA Plasma Membrane Transport Proteins/genetics , GABA Plasma Membrane Transport Proteins/metabolism , Mice , gamma-Aminobutyric Acid/metabolism , Male , Glutamate Decarboxylase/metabolism , Glutamate Decarboxylase/genetics , Anxiety/genetics , Anxiety/metabolism , Symporters/genetics , Symporters/metabolism , K Cl- Cotransporters , Behavior, Animal , Mice, Inbred C57BL , Depression/genetics , Depression/metabolism
9.
Int J Mol Sci ; 25(10)2024 May 12.
Article En | MEDLINE | ID: mdl-38791314

Obesity is associated with alterations in lipid metabolism and gut microbiota dysbiosis. This study investigated the effects of puerarin, a bioactive isoflavone, on lipid metabolism disorders and gut microbiota in high-fat diet (HFD)-induced obese mice. Supplementation with puerarin reduced plasma alanine aminotransferase, liver triglyceride, liver free fatty acid (FFA), and improved gut microbiota dysbiosis in obese mice. Puerarin's beneficial metabolic effects were attenuated when farnesoid X receptor (FXR) was antagonized, suggesting FXR-mediated mechanisms. In hepatocytes, puerarin ameliorated high FFA-induced sterol regulatory element-binding protein (SREBP) 1 signaling, inflammation, and mitochondrial dysfunction in an FXR-dependent manner. In obese mice, puerarin reduced liver damage, regulated hepatic lipogenesis, decreased inflammation, improved mitochondrial function, and modulated mitophagy and ubiquitin-proteasome pathways, but was less effective in FXR knockout mice. Puerarin upregulated hepatic expression of FXR, bile salt export pump (BSEP), and downregulated cytochrome P450 7A1 (CYP7A1) and sodium taurocholate transporter (NTCP), indicating modulation of bile acid synthesis and transport. Puerarin also restored gut microbial diversity, the Firmicutes/Bacteroidetes ratio, and the abundance of Clostridium celatum and Akkermansia muciniphila. This study demonstrates that puerarin effectively ameliorates metabolic disturbances and gut microbiota dysbiosis in obese mice, predominantly through FXR-dependent pathways. These findings underscore puerarin's potential as a therapeutic agent for managing obesity and enhancing gut health, highlighting its dual role in improving metabolic functions and modulating microbial communities.


Diet, High-Fat , Gastrointestinal Microbiome , Isoflavones , Liver , Obesity , Receptors, Cytoplasmic and Nuclear , Animals , Isoflavones/pharmacology , Gastrointestinal Microbiome/drug effects , Diet, High-Fat/adverse effects , Receptors, Cytoplasmic and Nuclear/metabolism , Mice , Obesity/metabolism , Obesity/drug therapy , Liver/metabolism , Liver/drug effects , Male , Dysbiosis , Mice, Obese , Mice, Inbred C57BL , ATP Binding Cassette Transporter, Subfamily B, Member 11/metabolism , ATP Binding Cassette Transporter, Subfamily B, Member 11/genetics , Cholesterol 7-alpha-Hydroxylase/metabolism , Cholesterol 7-alpha-Hydroxylase/genetics , Mice, Knockout , Organic Anion Transporters, Sodium-Dependent/metabolism , Organic Anion Transporters, Sodium-Dependent/genetics , Symporters/metabolism , Symporters/genetics , Lipid Metabolism/drug effects , Hepatocytes/metabolism , Hepatocytes/drug effects , Akkermansia
10.
Cell Rep Med ; 5(5): 101543, 2024 May 21.
Article En | MEDLINE | ID: mdl-38697101

Cognitive impairment in the elderly is associated with alterations in bile acid (BA) metabolism. In this study, we observe elevated levels of serum conjugated primary bile acids (CPBAs) and ammonia in elderly individuals, mild cognitive impairment, Alzheimer's disease, and aging rodents, with a more pronounced change in females. These changes are correlated with increased expression of the ileal apical sodium-bile acid transporter (ASBT), hippocampal synapse loss, and elevated brain CPBA and ammonia levels in rodents. In vitro experiments confirm that a CPBA, taurocholic acid, and ammonia induced synaptic loss. Manipulating intestinal BA transport using ASBT activators or inhibitors demonstrates the impact on brain CPBA and ammonia levels as well as cognitive decline in rodents. Additionally, administration of an intestinal BA sequestrant, cholestyramine, alleviates cognitive impairment, normalizing CPBAs and ammonia in aging mice. These findings highlight the potential of targeting intestinal BA absorption as a therapeutic strategy for age-related cognitive impairment.


Aging , Ammonia , Bile Acids and Salts , Cognitive Dysfunction , Intestinal Absorption , Animals , Bile Acids and Salts/metabolism , Cognitive Dysfunction/metabolism , Cognitive Dysfunction/pathology , Intestinal Absorption/drug effects , Male , Female , Humans , Mice , Aging/metabolism , Ammonia/metabolism , Aged , Mice, Inbred C57BL , Cholestyramine Resin/pharmacology , Symporters/metabolism , Organic Anion Transporters, Sodium-Dependent/metabolism , Organic Anion Transporters, Sodium-Dependent/genetics , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Hippocampus/metabolism , Hippocampus/pathology , Rats , Aged, 80 and over
11.
J Med Chem ; 67(8): 6687-6704, 2024 Apr 25.
Article En | MEDLINE | ID: mdl-38574002

In the face of escalating metabolic disease prevalence, largely driven by modern lifestyle factors, this study addresses the critical need for novel therapeutic approaches. We have identified the sodium-coupled citrate transporter (NaCT or SLC13A5) as a target for intervention. Utilizing rational drug design, we developed a new class of SLC13A5 inhibitors, anchored by the hydroxysuccinic acid scaffold, refining the structure of PF-06649298. Among these, LBA-3 emerged as a standout compound, exhibiting remarkable potency with an IC50 value of 67 nM, significantly improving upon PF-06649298. In vitro assays demonstrated LBA-3's efficacy in reducing triglyceride levels in OPA-induced HepG2 cells. Moreover, LBA-3 displayed superior pharmacokinetic properties and effectively lowered triglyceride and total cholesterol levels in diverse mouse models (PCN-stimulated and starvation-induced), without detectable toxicity. These findings not only spotlight LBA-3 as a promising candidate for hyperlipidemia treatment but also exemplify the potential of targeted molecular design in advancing metabolic disorder therapeutics.


Hyperlipidemias , Humans , Animals , Mice , Hyperlipidemias/drug therapy , Hep G2 Cells , Structure-Activity Relationship , Symporters/antagonists & inhibitors , Symporters/metabolism , Male , Hypolipidemic Agents/pharmacology , Hypolipidemic Agents/chemistry , Hypolipidemic Agents/therapeutic use , Hypolipidemic Agents/pharmacokinetics , Drug Discovery , Mice, Inbred C57BL , Triglycerides/blood , Triglycerides/metabolism , Drug Design
12.
Invest Ophthalmol Vis Sci ; 65(4): 18, 2024 Apr 01.
Article En | MEDLINE | ID: mdl-38587441

Purpose: Fuchs endothelial corneal dystrophy (FECD) is a progressive blinding disorder, characterized by increased corneal endothelial excrescences (guttae), corneal endothelial cell loss, and edema. These symptoms are hypothesized to be caused by changes in the extracellular matrix (ECM) and mitochondrial dysfunction in the corneal endothelium. Despite this clinical and biological relevance, a comprehensive animal model that recapitulates all the major disease characteristics is currently unavailable. In this study, we develop such a model to improve our understanding of the signaling pathways involved in the FECD progression and develop strategies for early intervention. Method: To generate a comprehensive FECD model, we generated a double mutant mouse bearing tamoxifen-inducible knockdown of Slc4a11 and the Col8a2 (Q455K) mutation. We performed optical coherence tomography (OCT) and in vivo confocal microscopy using the Heidelberg Retinal Tomography 3 - Rostock Cornea module (HRT3-RCM) on the mice at 5 weeks of age before tamoxifen feeding to establish baseline values for corneal thickness, endothelial cell density, and test for the presence of guttae. We measured these parameters again post-tamoxifen treatment at 16 weeks of age. We collected corneas at 16 weeks to perform histopathology, immunofluorescence staining for tight junctions, adherens junctions, and oxidative stress. We evaluated endothelial pump function using a lactate assay. Results: The double mutant tamoxifen-fed animals showed the presence of guttae, and displayed increased corneal thickness and decreased endothelial cell density. Endothelial cells showed altered morphology with disrupted adherens junctions and elevated reactive oxygen species (ROS). Finally, we found that stromal lactate concentrations were elevated in the double mutant mice, indicative of compromised endothelial pump function. Conclusions: Overall, this mouse model recapitulates all the important phenotypic features associated with FECD.


Fuchs' Endothelial Dystrophy , Symporters , Animals , Mice , Fuchs' Endothelial Dystrophy/genetics , Endothelial Cells , Disease Models, Animal , Lactic Acid , Tamoxifen/pharmacology , Anion Transport Proteins
14.
Biol Pharm Bull ; 47(4): 764-770, 2024.
Article En | MEDLINE | ID: mdl-38569835

L-Lactate transport via monocarboxylate transporters (MCTs) in the central nervous system, represented by the astrocyte-neuron lactate shuttle (ANLS), is crucial for the maintenance of brain functions, including memory formation. Previously, we have reported that MCT1 contributes to L-lactate transport in normal human astrocytes. Therefore, in this study, we aimed to identify transporters that contribute to L-lactate transport in human neurons. SH-SY5Y cells, which are used as a model for human neurons, were differentiated using all-trans-retinoic acid. L-Lactate uptake was measured using radiolabeled L-lactate, and the expression of MCT proteins was confirmed Western blotting. L-Lactate transport was pH-dependent and saturated at high concentrations. Kinetic analysis suggested that L-lactate uptake was biphasic. Furthermore, MCT1, 2 selective inhibitors inhibited L-lactate transport. In addition, the expression of MCT1 and 2 proteins, but not MCT4, was confirmed. In this study, we demonstrated that MCT1 and 2 are major contributors to L-lactate transport in differentiated human neuroblastoma SH-SY5Y cells from the viewpoint of kinetic analysis. These results lead to a better understanding of ANLS in humans, and further exploration of the factors that can promote MCT1 and 2 functions is required.


Neuroblastoma , Symporters , Humans , Kinetics , Biological Transport , Carrier Proteins/metabolism , Lactic Acid/metabolism , Membrane Transport Proteins/metabolism , Monocarboxylic Acid Transporters/metabolism , Symporters/metabolism
15.
Biomolecules ; 14(4)2024 Mar 25.
Article En | MEDLINE | ID: mdl-38672410

Inflammation is a physiological condition characterized by a complex interplay between different cells handled by metabolites and specific inflammatory-related molecules. In some pathological situations, inflammation persists underlying and worsening the pathological state. Over the years, two membrane transporters namely OCTN1 (SLC22A4) and OCTN2 (SLC22A5) have been shown to play specific roles in inflammation. These transporters form the OCTN subfamily within the larger SLC22 family. The link between these proteins and inflammation has been proposed based on their link to some chronic inflammatory diseases such as asthma, Crohn's disease (CD), and rheumatoid arthritis (RA). Moreover, the two transporters show the ability to mediate the transport of several compounds including carnitine, carnitine derivatives, acetylcholine, ergothioneine, and gut microbiota by-products, which have been specifically associated with inflammation for their anti- or proinflammatory action. Therefore, the absorption and distribution of these molecules rely on the presence of OCTN1 and OCTN2, whose expression is modulated by inflammatory cytokines and transcription factors typically activated by inflammation. In the present review, we wish to provide a state of the art on OCTN1 and OCTN2 transport function and regulation in relationships with inflammation and inflammatory diseases focusing on the metabolic signature collected in different body districts and gene polymorphisms related to inflammatory diseases.


Inflammation , Organic Cation Transport Proteins , Solute Carrier Family 22 Member 5 , Symporters , Humans , Inflammation/metabolism , Solute Carrier Family 22 Member 5/metabolism , Solute Carrier Family 22 Member 5/genetics , Animals , Organic Cation Transport Proteins/metabolism , Organic Cation Transport Proteins/genetics , Ergothioneine/metabolism , Crohn Disease/metabolism , Crohn Disease/genetics , Crohn Disease/pathology , Arthritis, Rheumatoid/metabolism , Arthritis, Rheumatoid/genetics , Gastrointestinal Microbiome , Carnitine/metabolism , Asthma/metabolism , Asthma/genetics , Acetylcholine/metabolism
16.
Sci Rep ; 14(1): 9355, 2024 04 23.
Article En | MEDLINE | ID: mdl-38654093

Thyroid hormones (TH) play critical roles during nervous system development and patients carrying coding variants of MCT8 (monocarboxylate transporter 8) or THRA (thyroid hormone receptor alpha) present a spectrum of neurological phenotypes resulting from perturbed local TH action during early brain development. Recently, human cerebral organoids (hCOs) emerged as powerful in vitro tools for disease modelling recapitulating key aspects of early human cortex development. To begin exploring prospects of this model for thyroid research, we performed a detailed characterization of the spatiotemporal expression of MCT8 and THRA in developing hCOs. Immunostaining showed MCT8 membrane expression in neuronal progenitor cell types including early neuroepithelial cells, radial glia cells (RGCs), intermediate progenitors and outer RGCs. In addition, we detected robust MCT8 protein expression in deep layer and upper layer neurons. Spatiotemporal SLC16A2 mRNA expression, detected by fluorescent in situ hybridization (FISH), was highly concordant with MCT8 protein expression across cortical cell layers. FISH detected THRA mRNA expression already in neuroepithelium before the onset of neurogenesis. THRA mRNA expression remained low in the ventricular zone, increased in the subventricular zone whereas strong THRA expression was observed in excitatory neurons. In combination with a robust up-regulation of known T3 response genes following T3 treatment, these observations show that hCOs provide a promising and experimentally tractable model to probe local TH action during human cortical neurogenesis and eventually to model the consequences of impaired TH function for early cortex development.


Cerebral Cortex , Monocarboxylic Acid Transporters , Neurogenesis , Organoids , RNA, Messenger , Symporters , Thyroid Hormone Receptors alpha , Female , Humans , Pregnancy , Cerebral Cortex/embryology , Cerebral Cortex/metabolism , Gene Expression Regulation, Developmental , Monocarboxylic Acid Transporters/genetics , Monocarboxylic Acid Transporters/metabolism , Neural Stem Cells/metabolism , Neural Stem Cells/cytology , Neurogenesis/genetics , Neurons/metabolism , Organoids/metabolism , Pregnancy Trimester, First/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Symporters/genetics , Symporters/metabolism , Thyroid Hormone Receptors alpha/genetics , Thyroid Hormone Receptors alpha/metabolism , Thyroid Hormones/metabolism , Thyroid Hormones/genetics
17.
J Cell Mol Med ; 28(9): e18352, 2024 May.
Article En | MEDLINE | ID: mdl-38685685

Gliomas, the most lethal tumours in brain, have a poor prognosis despite accepting standard treatment. Limited benefits from current therapies can be attributed to genetic, epigenetic and microenvironmental cues that affect cell programming and drive tumour heterogeneity. Through the analysis of Hi-C data, we identified a potassium-chloride co-transporter SLC12A5 associated with disrupted topologically associating domain which was downregulated in tumour tissues. Multiple independent glioma cohorts were included to analyse the characterization of SLC12A5 and found it was significantly associated with pathological features, prognostic value, genomic alterations, transcriptional landscape and drug response. We constructed two SLC12A5 overexpression cell lines to verify the function of SLC12A5 that suppressed tumour cell proliferation and migration in vitro. In addition, SLC12A5 was also positively associated with GABAA receptor activity and negatively associated with pro-tumour immune signatures and immunotherapy response. Collectively, our study provides a comprehensive characterization of SLC12A5 in glioma and supports SLC12A5 as a potential suppressor of disease progression.


Brain Neoplasms , Cell Proliferation , Gene Expression Regulation, Neoplastic , Glioma , K Cl- Cotransporters , Symporters , Humans , Glioma/genetics , Glioma/pathology , Glioma/metabolism , Cell Proliferation/genetics , Cell Line, Tumor , Brain Neoplasms/genetics , Brain Neoplasms/pathology , Brain Neoplasms/metabolism , Symporters/genetics , Symporters/metabolism , Cell Movement/genetics , Prognosis , Receptors, GABA-A/metabolism , Receptors, GABA-A/genetics
18.
eNeuro ; 11(4)2024 Apr.
Article En | MEDLINE | ID: mdl-38604775

A sublethal ischemic episode [termed preconditioning (PC)] protects neurons in the brain against a subsequent severe ischemic injury. This phenomenon is known as brain ischemic tolerance and has received much attention from researchers because of its robust neuroprotective effects. We have previously reported that PC activates astrocytes and subsequently upregulates P2X7 receptors, thereby leading to ischemic tolerance. However, the downstream signals of P2X7 receptors that are responsible for PC-induced ischemic tolerance remain unknown. Here, we show that PC-induced P2X7 receptor-mediated lactate release from astrocytes has an indispensable role in this event. Using a transient focal cerebral ischemia model caused by middle cerebral artery occlusion, extracellular lactate levels during severe ischemia were significantly increased in mice who experienced PC; this increase was dependent on P2X7 receptors. In addition, the intracerebroventricular injection of lactate protected against cerebral ischemic injury. In in vitro experiments, although stimulation of astrocytes with the P2X7 receptor agonist BzATP had no effect on the protein levels of monocarboxylate transporter (MCT) 1 and MCT4 (which are responsible for lactate release from astrocytes), BzATP induced the plasma membrane translocation of these MCTs via their chaperone CD147. Importantly, CD147 was increased in activated astrocytes after PC, and CD147-blocking antibody abolished the PC-induced facilitation of astrocytic lactate release and ischemic tolerance. Taken together, our findings suggest that astrocytes induce ischemic tolerance via P2X7 receptor-mediated lactate release.


Astrocytes , Ischemic Preconditioning , Lactic Acid , Mice, Inbred C57BL , Monocarboxylic Acid Transporters , Receptors, Purinergic P2X7 , Animals , Astrocytes/metabolism , Astrocytes/drug effects , Ischemic Preconditioning/methods , Lactic Acid/metabolism , Lactic Acid/pharmacology , Receptors, Purinergic P2X7/metabolism , Male , Monocarboxylic Acid Transporters/metabolism , Basigin/metabolism , Brain Ischemia/metabolism , Symporters/metabolism , Infarction, Middle Cerebral Artery/metabolism , Disease Models, Animal , Muscle Proteins/metabolism , Adenosine Triphosphate/metabolism , Adenosine Triphosphate/pharmacology , Mice , Cells, Cultured , Brain/metabolism , Mice, Knockout
19.
Exp Neurol ; 377: 114782, 2024 Jul.
Article En | MEDLINE | ID: mdl-38641126

Elevated transport of Caveolin-1 (CAV-1) vesicles within vascular endothelial cells constitutes a significant secondary pathogenic event contributing to the compromise of the blood-brain barrier (BBB) post-traumatic brain injury (TBI). While Wnt/ß-catenin signaling is recognized for its critical involvement in angiogenesis and the maintenance of BBB integrity, its influence on vascular endothelial transcytosis in the aftermath of TBI is not well-defined. This study aims to elucidate the impact of Wnt/ß-catenin signaling on cerebrovascular vesicular transcytosis following TBI. In this experiment, adult male wild-type (WT) C57BL/6 mice underwent various interventions. TBI was induced utilizing the controlled cortical impact technique. Post-TBI, mice were administered either an inhibitor or an agonist of Wnt signaling via intraperitoneal injection. Recombinant adeno-associated virus (rAAV) was administered intracerebroventricularly to modulate the expression of the CAV-1 inhibitory protein, Major facilitator superfamily domain-containing 2a (Mfsd2a). This research utilized Evans blue assay, Western blot analysis, immunofluorescence, transmission electron microscopy, and neurobehavioral assessments. Post-TBI observations revealed substantial increases in macromolecule (Evans blue and albumin) leakage, CAV-1 transport vesicle count, astrocyte end-feet edema, and augmented aquaporin-4 (AQP4) expression, culminating in BBB disruption. The findings indicate that Wnt signaling pathway inhibition escalates CAV-1 transport vesicle activity and aggravates BBB compromise. Conversely, activating this pathway could alleviate BBB damage by curtailing CAV-1 vesicle presence. Post-TBI, there is a diminution in Mfsd2a expression, which is directly influenced by the modulation of WNT signals. Employing a viral approach to regulate Mfsd2a, we established that its down-regulation undermines the protective benefits derived from reducing CAV-1 transport vesicles through WNT signal enhancement. Moreover, we verified that the WNT signaling agonist LiCl notably ameliorates neurological deficits following TBI in mice. Collectively, our data imply that Wnt/ß-catenin signaling presents a potential therapeutic target for safeguarding against BBB damage and enhancing neurological function after TBI.


Blood-Brain Barrier , Brain Injuries, Traumatic , Caveolin 1 , Mice, Inbred C57BL , Transcytosis , Wnt Signaling Pathway , Animals , Blood-Brain Barrier/metabolism , Blood-Brain Barrier/pathology , Blood-Brain Barrier/drug effects , Brain Injuries, Traumatic/metabolism , Brain Injuries, Traumatic/pathology , Mice , Male , Wnt Signaling Pathway/drug effects , Wnt Signaling Pathway/physiology , Transcytosis/drug effects , Transcytosis/physiology , Caveolin 1/metabolism , Symporters
20.
Viruses ; 16(4)2024 04 05.
Article En | MEDLINE | ID: mdl-38675909

Adjuvant systemic therapies effectively reduce the risk of breast cancer recurrence and metastasis, but therapy resistance can develop in some patients due to breast cancer stem cells (BCSCs). Oncolytic adenovirus (OAd) represents a promising therapeutic approach as it can specifically target cancer cells. However, its potential to target BCSCs remains unclear. Here, we evaluated a Cox-2 promoter-controlled, Ad5/3 fiber-modified OAd designed to encode the human sodium iodide symporter (hNIS) in breast cancer models. To confirm the potential of OAds to target BCSCs, we employed BCSC-enriched estrogen receptor-positive (ER+) paclitaxel-resistant (TaxR) cells and tumorsphere assays. OAd-hNIS demonstrated significantly enhanced binding and superior oncolysis in breast cancer cells, including ER+ cells, while exhibiting no activity in normal mammary epithelial cells. We observed improved NIS expression as the result of adenovirus death protein deletion. OAd-hNIS demonstrated efficacy in targeting TaxR BCSCs, exhibiting superior killing and hNIS expression compared to the parental cells. Our vector was capable of inhibiting tumorsphere formation upon early infection and reversing paclitaxel resistance in TaxR cells. Importantly, OAd-hNIS also destroyed already formed tumorspheres seven days after their initiation. Overall, our findings highlight the promise of OAd-hNIS as a potential tool for studying and targeting ER+ breast cancer recurrence and metastasis.


Adenoviridae , Breast Neoplasms , Drug Resistance, Neoplasm , Neoplastic Stem Cells , Oncolytic Virotherapy , Oncolytic Viruses , Paclitaxel , Humans , Neoplastic Stem Cells/drug effects , Neoplastic Stem Cells/metabolism , Breast Neoplasms/therapy , Breast Neoplasms/drug therapy , Paclitaxel/pharmacology , Adenoviridae/genetics , Adenoviridae/physiology , Oncolytic Viruses/genetics , Oncolytic Viruses/physiology , Oncolytic Virotherapy/methods , Female , Cell Line, Tumor , Animals , Mice , Symporters/metabolism , Symporters/genetics , Genetic Vectors/genetics
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