Search Results (136)

Bone marrow-derived mononuclear cells (BMMCs) have shown beneficial effects on tissue repair, largely attributed to the paracrine action of bioactive mediators such as lysophosphatidic acid (LPA). This study aimed to evaluate the effects of BMMC treatment in a rat model of renal ischemia/reperfusion (I/R) injury, focusing on LPA-related molecular pathways. Male Wistar rats were divided into three groups: control; I/R, subjected to bilateral renal artery clamping for 30 min followed by 24 h of reperfusion; and I/R + BMMC, which received 1 × 10⁶ BMMCs per kidney directly into the renal capsule post-ischemia. During reperfusion, the rats were placed in metabolic cages for urine collection, renal function and protein expression. BMMC treatment did not reverse the I/R-induced increase in urine volume or decrease in glomerular filtration rate, serum potassium, or filtered sodium load. However, it prevented proteinuria, increased blood urea nitrogen, and enhanced urinary potassium excretion. Mechanistically, BMMC treatment prevented I/R-induced upregulation of LPAR1, downregulated LPAR2 and LPAR3, restored plasma LPA levels, and reduced renal autotaxin content. These results suggest that BMMCs modulate harmful LPA-related signaling and may contribute to renal protection through paracrine mechanisms in the setting of acute I/R injury. Full article

Ceramide 1-phosphate (C1P) is a key regulator of cell proliferation and survival in both normal and transformed cells. Major pathways implicated in the mitogenic actions of C1P include activation of the mitogen-activated protein kinases (MAPKs) ERK1-2 and JNK, as well as stimulation of the phosphatidylinositol 3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, the product of retinoblastoma, or the sphingomyelin synthase (SMS)/diacylglycerol (DAG)/protein kinase C-alpha (PKC-α) pathway. C1P-stimulated cell proliferation can also be mediated through enhanced secretion of vascular endothelial growth factor (VEGF) in macrophages or by releasing lysophosphatidic acid (LPA) in myoblasts. Also, the production of low levels of reactive oxygen species (ROS) can mediate the stimulation of cell growth by C1P, particularly in macrophages. Upregulation of the PI3K/Akt/mTOR pathway is also involved in the inhibition of cell death by C1P, which can also contribute to cell survival by blocking the activity of the ceramide-generating enzymes acid sphingomyelinase (ASMase) and serine palmitoyl transferase (SPT). Moreover, C1P-promoted cell survival involves upregulation of inducible nitric oxide synthase (iNOS) and the subsequent production of nitric oxide (NO). Using photosensitive C1P analogues, it could be concluded that promotion of cell growth and inhibition of cell death were elicited by intracellularly generated C1P in a receptor-independent manner. The aim of the present review is to evaluate in detail the implication of the CerK/C1P axis in controlling cell proliferation and survival in mammalian cells, as well as to discuss and update on the molecular mechanisms by which C1P can accomplish these actions. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-β plaques, tau hyperphosphorylation, and chronic neuroinflammation. Emerging evidence suggests a crucial role of lipid signaling pathways in AD pathogenesis, particularly those mediated by autotaxin (ATX) and lysophosphatidic acid (LPA). ATX, an enzyme responsible for LPA production, has been implicated in neuroinflammatory processes, blood–brain barrier dysfunction, and neuronal degeneration. LPA signaling, through its interaction with specific G-protein-coupled receptors, influences neuroinflammation, synaptic plasticity, and tau pathology, all of which contribute to AD progression. This review synthesizes recent findings on the ATX/LPA axis in AD, exploring its potential as a biomarker and therapeutic target. Understanding the mechanistic links between ATX, LPA, and AD pathology may open new avenues for disease-modifying strategies. Full article

Lysophosphatidic acid (LPA), a key bioactive lipid, modulates cellular functions through interactions with LPA receptors (LPAR1-6) of the G protein-coupled receptor (GPCR) family, participating in both physiological and pathological processes. While LPA/LPAR signaling typically promotes cancer progression by regulating angiogenesis and cancer cell metastasis, our study unexpectedly reveals that LPA exhibits an inhibitory effect on cellular activity in hepatocellular carcinoma (HCC). We further investigate the specific receptor subtypes mediating these effects and elucidate the underlying mechanisms at the cellular, tissue, and organismal levels. Pharmacological studies demonstrated that LPA predominantly inhibits HCC progression through activation of LPAR6. Mechanistically, LPA/LPAR6 activation suppresses HCC proliferation, migration, and epithelial–mesenchymal transition (EMT). In vivo, LPAR6 overexpression in a nude mouse xenograft model significantly reduced tumor growth rate and volume, accompanied by decreased Ki-67 expression in tumor tissues, as shown by immunohistochemical analysis. Transcriptomic analysis combined with Western blot experiments demonstrated that LPA/LPAR6 inhibits YAP/TAZ nuclear translocation, thereby suppressing HCC cell proliferation and migration. In conclusion, these findings suggest that enhancing LPAR6 expression or developing LPAR6 agonists may offer a promising therapeutic strategy for adjuvant cancer treatment. Full article

Comparative studies using lysophosphatidic acid (LPA) and the synthetic agonist, oleoyl-methoxy glycerophosphothionate (OMPT), in cells expressing the LPA₃ receptor revealed differences in the action of these agents. The possibility that more than one recognition cavity might exist for these ligands in the LPA₃ receptor was considered. We performed agonist docking studies exploring the whole protein to obtain tridimensional details of the ligand–receptor interaction. Functional in cellulo experiments using mutants were also executed. Our work includes blind docking using the unrefined and refined proteins subjected to hot spot predictions. Distinct ligand protonation (charge −1 and −2) states were evaluated. One LPA recognition cavity is located near the lower surface of the receptor close to the cytoplasm (Lower Cavity). OMPT displayed an affinity for an additional identification cavity detected in the transmembrane and extracellular regions (Upper Cavity). Docking targeted to Trp102 favored binding of both ligands in the transmembrane domain near the extracellular areas (Upper Cavity), but the associating amino acids were not identical due to close sub-cavities. A receptor model was generated using AlphaFold3, which properly identified the transmembrane regions of the sequence and co-modeled the lipid environment accordingly. These two models independently generated (with and without the membrane) and adopted essentially the same conformation, validating the data obtained. A DeepSite analysis of the model predicted two main binding pockets, providing additional confidence in the predicted ligand-binding regions and support for the relevance of the docking-based interaction models. In addition, mutagenesis was performed of the amino acids of the two detected cavities. In the in cellulo studies, LPA action was much less affected by the distinct mutations than that of OMPT (which was almost abolished). Therefore, docking and functional data indicate the presence of distinct agonist binding cavities in the LPA₃ receptor. Full article

The lysophosphatidic acid receptor 1 (LPAR1) is one of the six cognate G protein-coupled receptors of the bioactive, growth factor-like phospholipid lysophosphatidic acid (LPA). LPAR1 is widely expressed in different cell types and mediates many LPA effects. LPAR1 has been implicated in several chronic inflammatory diseases, and especially pulmonary fibrosis, where it has been established as a promising therapeutic target. Herein, we present the generation of several Lpar1 mouse strains through genetic recombination. These strains include an initial versatile Lpar1 strain (tm1a) from which three other strains derive: an Lpar1 reporter knockout strain (tm1b) where LacZ has replaced exon 3 of Lpar1; a “floxed” Lpar1 strain (tm1c), where exon 3 is flanked by two loxP sites allowing conditional, cell-specific Lpar1 inactivation; and a complete KO strain of Lpar1 (tm1d), where exon 3 has been deleted. The generated strains are novel genetic tools, that can have various applications in studying LPA-LPAR1 signaling and its role in normal physiology and disease. Full article

Lysophosphatidic acid (LPA) is a small bioactive phospholipid which plays an important role during embryonic development and promotes developmental potential of in-vitro-produced (IVP) embryos in several species, including sheep and pigs. In bovines, LPA accelerates IVP blastocyst formation through the Hippo/YAP pathway. However, other LPA effects and its potential receptors during bovine embryo development are less clear. In this study, we used enzyme-linked immunosorbent assay (ELISA) to assess the presence of LPA in bovine oviductal fluid and determine cell apoptosis in embryos after LPA stimulation by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and quantitative reverse transcription polymerase chain reaction (qRT-PCR). We further evaluated potential receptors of LPA through molecular docking, RNA-seq data analysis and quantitative RT-PCR. LPA was found to be present in oviductal fluid. An increase in total cell number and a decrease in apoptosis levels were detected in day 7 blastocysts after LPA treatment. Among eight LPA receptors (LPARs), GPR87 and LPAR2 showed the highest affinity with LPA and their transcripts were expressed in embryos after the 16-cell stage in RNA-seq and qRT-PCR analysis. However, only the expression of LPAR2 was significantly increased in day 6 blastocysts after LPA stimulation, indicating its potential role in LPA-mediated signaling pathways. Our data highlight the positive effects of LPA on embryos and enrich information of related signaling mediators of LPA during embryonic development. Full article

Ginseng, a traditional herbal medicine with a long history of use, is known to support human health, particularly by influencing brain function. Recent studies have identified gintonin, a lysophosphatidic acid (LPA) receptor ligand derived from ginseng, as a key bioactive. However, the specific LPA receptor subtypes targeted by gintonin in the human brain to exert its anti-Alzheimer’s (AD) effects remain unclear. This study aimed to elucidate the LPA receptor subtype targeted by gintonin in the human cortex. Using a fluorescent gintonin conjugate, we investigated receptor binding in cortical samples from healthy individuals (n = 4) and AD patients (n = 4). Our results demonstrated that fluorescent gintonin selectively binds to human cortical neurons rather than glial cells and that gintonin-binding sites are co-localized with the LPA4 receptor subtype. Furthermore, the expression of LPA4 receptors was significantly reduced in the cortical neurons of AD patients. These results suggest that the LPA4 receptor may serve as a novel histopathological marker for AD and represent a promising therapeutic target for gintonin-based prevention and treatment strategies. Full article

The autotaxin–lysophosphatidic acid receptor (ATX-LPAR) signaling axis is pivotal in various clinical conditions, including cancer and autoimmune disorders. This axis promotes tumorigenicity by interacting with the tumor microenvironment, facilitating metastasis, and conceding antitumor immunity, thereby fostering resistance to conventional cancer therapies. Recent studies highlight the promise of ATX/LPAR inhibitors in combination with conventional chemotherapeutic drugs to overcome some forms of this resistance, representing a novel therapeutic strategy. In the current study, we employed structure-based virtual screening, integrating pharmacophore modeling and molecular docking, to identify MolPort-137 as a novel ATX inhibitor with an IC₅₀ value of 1.6 ± 0.2 μM in an autotaxin enzyme inhibition assay. Molecular dynamics simulations and binding free energy calculations elucidated the binding mode of MolPort-137 and its critical amino acid interactions. Remarkably, MolPort-137 exhibited no cytotoxicity as a single agent but enhanced the effectiveness of paclitaxel in 4T1 murine breast carcinoma cells and resensitized taxol-resistant cells to paclitaxel treatment, which highlights its potential in combination therapy. Full article

The active metabolite of vitamin D3, calcitriol (1,25D), is widely recognised for its direct anti-proliferative and pro-differentiation effects. However, 1,25D is calcaemic, which restricts its clinical use for cancer treatment. Non-calcaemic agonists of the vitamin D receptor (VDR) could be better candidates for cancer treatment. In this study, we examined the influence of the hydroxylated lithocholic acid derivative CAR-R on osteosarcoma (OS) cell (MG63) growth and differentiation. Treatment of MG63 cells with CAR-R inhibited growth under conventional and hypoxic conditions. Co-treating cells with CAR-R and a lysophosphatidic acid (LPA) analogue resulted in their differentiation, as supported by synergistic increases in alkaline phosphatase (ALP) activity. Under hypoxic conditions, however, this differentiation response was attenuated. The importance of observed increases in hypoxia inducible factors (HIFs) were investigated through targeted disruption using pharmacological and genetic approaches. Disruption elicited a reduction in ALP activity, suggesting an important role for HIFs in OS differentiation. Finally, we examined the expression of the VDR protein. Hypoxic MG63s expressed less VDR, with the levels increasing with CAR-R exposure. Whilst these findings are encouraging, future studies aimed at bolstering the pro-differentiating effect of CAR-R under hypoxic conditions are warranted if this agent is to gain traction in the treatment of OS. Full article

Background: Lysophosphatidic acid (LPA) receptor 3 (LPA₃) is involved in many physiological and pathophysiological actions of this bioactive lipid, particularly in cancer. The actions of LPA and oleoyl-methoxy glycerophosphothionate (OMPT) were compared in LPA₃-transfected HEK 293 cells. Methods: Receptor phosphorylation, ERK 1/2 activation, LPA₃-β-arrestin 2 interaction, and changes in intracellular calcium were analyzed. Results: Our data indicate that LPA and OMPT increased LPA₃ phosphorylation, OMPT being considerably more potent than LPA. OMPT was also more potent than LPA to activate ERK 1/2. In contrast, OMPT was less effective in increasing intracellular calcium than LPA. The LPA-induced LPA₃-β-arrestin 2 interaction was fast and robust, whereas that induced by OMPT was only detected at 60 min of incubation. LPA- and OMPT-induced receptor internalization was fast, but that induced by OMPT was more marked. LPA-induced internalization was blocked by Pitstop 2, whereas OMPT-induced receptor internalization was partially inhibited by Pitstop 2 and Filipin and entirely by the combination of both. When LPA-stimulated cells were rechallenged with 1 µM LPA, hardly any response was detected, i.e., a “refractory” state was induced. However, a conspicuous and robust response was observed if OMPT was used as the second stimulus. Conclusions: The differences in these agents’ actions suggest that OMPT is a biased agonist. These findings suggest that two binding sites for these agonists might exist in the LPA₃ receptor, one showing a very high affinity for OMPT and another likely shared by LPA and OMPT (structural analogs) with lower affinity. Full article

Ginseng has anti-hyperglycemic effects. Gintonin, a glycolipoprotein derived from ginseng, also stimulates insulin release from pancreatic beta cells. However, the role of gintonin in glucose metabolism within skeletal muscle is unknown. Here, we showed the effect of gintonin on glucose uptake, glycogen content, glucose transporter (GLUT) 4 expression, and adenosine triphosphate (ATP) content in C2C12 myotubes. Gintonin (3–30 μg/mL) dose-dependently stimulated glucose uptake in myotubes. The expression of GLUT4 on the cell membrane was increased by gintonin treatment. Treatment with 1–3 μg/mL of gintonin increased glycogen content in myotubes, but the content was decreased at 30 μg/mL of gintonin. The ATP content in myotubes increased following treatment with 10–100 μg/mL gintonin. Gintonin transiently elevated intracellular calcium concentrations and increased the phosphorylation of extracellular signal-regulated kinase (ERK). Gintonin-induced transient calcium increases were inhibited by treatment with the lysophosphatidic acid receptor inhibitor Ki16425, the phospholipase C inhibitor U73122, and the inositol 1,4,5-trisphosphate receptor antagonist 2-aminoethoxydiphenyl borate. Gintonin-stimulated glucose uptake was decreased by treatment with U73122, the intracellular calcium chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetra(acetoxymethyl) ester, and the ERK inhibitor PD98059. These results show that gintonin plays a role in glucose metabolism by increasing glucose uptake through transient calcium increases and ERK signaling pathways. Thus, gintonin may be beneficial for glucose metabolism control. Full article

Background: The Autotaxin (ATX)-lysophosphatidic acid (LPA) axis is involved in decreasing radiation sensitivity of breast tumor cells. This study aims to further elucidate the effect of irradiation on the ATX-LPA axis and cytokine secretion in different breast cancer cell lines to identify suitable breast cancer subtypes for targeted therapies. Methods: Different breast cancer cell lines (MCF-7 (luminal A), BT-474 (luminal B), SKBR-3 (HER2-positive), MDA-MB-231 and MDA-MB-468 (triple-negative)) and the breast epithelial cell line MCF-10A were irradiated. The influence of irradiation on LPA receptor (LPAR) expression, ATX expression, and Interleukin (IL)-6 and IL-8 secretion was analyzed. Further, the effect of IL-6 and IL-8 on ATX expression of adipose-derived stem cells (ADSC) was investigated. Results: Irradiation increased ATX and LPAR2 expression in MDA-MB-231 cells. Additionally, IL-6 secretion was enhanced in MDA-MB-231, and IL-8 secretion in MDA-MB-231 and MDA-MB-468. Stimulation of ADSC with IL-6 and IL-8 increased ATX expression in ADSC. Conclusions: Targeting ATX or its downstream signaling pathways might enhance the sensitivity of triple-negative breast cancer cells to radiation. Further exploration of the interplay between irradiation, the ATX-LPA axis, and inflammatory cytokines may elucidate novel pathways for overcoming radioresistance and improving individual treatment outcomes. Full article

The development of drug resistance in cancer cells poses a significant challenge for treatment, with nearly 90% of cancer-related deaths attributed to it. Over 50% of ovarian cancer patients and 30–40% of breast cancer patients exhibit resistance to therapies such as Taxol. Previous literature has shown that cytotoxic cancer therapies and ionizing radiation damage tumors, prompting cancer cells to exploit the autotaxin (ATX)–lysophosphatidic acid (LPA)–lysophosphatidic acid receptor (LPAR) signaling axis to enhance survival pathways, thus reducing treatment efficacy. Therefore, targeting this signaling axis has become a crucial strategy to overcome some forms of cancer resistance. Addressing this challenge, we identified and assessed ATX-1d, a novel compound targeting ATX, through computational methods and in vitro assays. ATX-1d exhibited an IC₅₀ of 1.8 ± 0.3 μM for ATX inhibition and demonstrated a significant binding affinity for ATX, as confirmed by MM-GBSA, QM/MM-GBSA, and SAPT in silico methods. ATX-1d significantly amplified the potency of paclitaxel, increasing its effectiveness tenfold in 4T1 murine breast carcinoma cells and fourfold in A375 human melanoma cells without inducing cytotoxic effects as a single agent. Full article

Irritable bowel syndrome (IBS) is a gastrointestinal (GI) disease accompanied by changes in bowel habits without any specific cause. Gintonin is a newly isolated glycoprotein from ginseng that is a lysophosphatidic acid (LPA) receptor ligand. To investigate the efficacy and mechanisms of action of gintonin in IBS, we developed a zymosan-induced IBS murine model. In addition, electrophysiological experiments were conducted to confirm the relevance of various ion channels. In mice, gintonin restored colon length and weight to normal and decreased stool scores, whilst food intake remained constant. Colon mucosal thickness and inflammation-related tumor necrosis factor-α levels were decreased by gintonin, along with a reduction in pain-related behaviors. In addition, the fecal microbiota from gintonin-treated mice had relatively more Lactobacillaceae and Lachnospiraceae and less Bacteroidaceae than microbiota from the control mice. Moreover, gintonin inhibited transient receptor potential vanilloid (TRPV) 1 and TRPV4 associated with visceral hypersensitivity and voltage-gated Na⁺ 1.5 channels associated with GI function. These results suggest that gintonin may be one of the effective components in the treatment of IBS. Full article