Lysophosphatidic acid signalling in development

Skin Metabolic Signatures of Psoriasis and Psoriasis Concurrent with Metabolic Syndrome

Purpose

Psoriasis is a complex inflammatory skin disorder that is closely associated with metabolic syndrome (MetS). Limited information is available on skin metabolic changes in psoriasis; the effect of concurrent MetS on psoriatic skin metabolite levels is unknown. We aimed to expand this information through skin metabolomic analysis.

Patients and Methods

Untargeted metabolomics was conducted using skin samples from 38 patients with psoriasis vulgaris with MetS (PVMS), 23 patients with psoriasis vulgaris without MetS (PVNMS), and 10 healthy controls (HC). Data analyses, including multivariate statistical analysis, KEGG pathway enrichment analysis, correlation analysis, and receiver operating characteristic curve analysis, were performed.

Results

Significant discrepancies were found between skin metabolites in the HC and PVNMS groups, particularly those involved in nucleotide and glycerophospholipid metabolism. Fifteen of these metabolites were positively correlated with psoriasis severity. Furthermore, MetS was found to affect the metabolic profiles of patients with psoriasis. There were some metabolites with consistent alterations in both the PVNMS/HC and PVMS/PVNMS comparisons.

Conclusion

This study may provide new insights into the link between skin metabolism and psoriatic inflammation and the mechanism underlying the interaction between psoriasis and MetS.

Inhibition of lysophosphatidic acid receptor 2 attenuates neonatal chronic lung disease in mice by preserving vascular and alveolar development

AIM

Bronchopulmonary dysplasia (BPD) is a common morbidity in extremely premature infants. Previous studies demonstrated the important role of lysophosphatidic acid (LPA) in inflammation in BPD. However, the role of LPA and its receptors in hyperoxia-induced vascular malformations in BPD remains to be elucidated.

METHODS AND RESULTS

Elevated plasma LPA levels were observed in mice with BPD compared to controls (792 vs. 607 ng/mL, p < 0.05). Inhibition of LPA signaling protected against hyperoxia-induced lung injury in neonatal mice, demonstrated by a 2.8-fold increase in pulmonary vascular density and a 14% reduction in alveolar enlargement. In vitro studies showed that LPA suppressed tube formation in human umbilical vein endothelial cells (HUVECs) by approximately 50%. LPA receptor 2 (LPA2) was identified as a functional LPA receptor in primary endothelial cells from the lungs of hyperoxic mice and in HUVECs under hyperoxic conditions. The LPA2 antagonist H2L5186303 enhanced the tube formation ability of HUVECs exposed to LPA, both under normoxia (4-fold) and hyperoxia (5-fold). Moreover, H2L5186303 significantly protected against hyperoxia-induced vascular malformation (2-fold) and improved alveolarization in neonatal mice (12% decrease in mean linear intercept, MLI). Early growth response 1 (EGR1) was characterized as a downstream target of LPA2, silencing EGR1 restored tube formation in HUVECs exposed to LPA and hyperoxia.

CONCLUSIONS

Our in vitro and in vivo findings demonstrate that the inhibition of LPA/LPA2 signaling mitigates hyperoxia-induced pulmonary vascular malformations, suggesting the LPA/LPA2-dependent signaling pathway has therapeutic potential for extremely premature infants with BPD.

Discovery of GS-2278, a Potent and Selective LPAR1 Antagonist for the Treatment of Idiopathic Pulmonary Fibrosis

We describe the discovery and preclinical characterization of a potent and selective lysophosphatidic acid receptor 1 (LPAR1) antagonist with a direct-acting antifibrotic mechanism. 18a was initially identified as a potent non-carboxylic acid LPAR1 antagonist in an LPA-induced myocardin-related transcription factor A (MRTF-A) nuclear translocation assay. Modifications to the aromatic elements in the structure allowed for improvements in metabolic stability and the mitigation of GSH adduct formation, but in vitro to in vivo clearance disconnects were observed with several potent sulfonamides (e.g., 27b) across preclinical species. Through modification of the sulfonamide, 42 (GS-2278) emerged as a potent LPAR1 antagonist with a suitable in vitro profile and desirable pharmacokinetic properties for oral QD dosing. GS-2278 dose-dependently blocked LPA-induced histamine release and demonstrated efficacy in an interventional model of bleomycin-induced lung fibrosis. However, CNS-related toxicity was observed in dogs, and based on these findings, the clinical development of GS-2278 for IPF was halted.

Study on the Therapeutic Effects and Mechanisms of Gintonin in Irritable Bowel Syndrome and Its Relationship with TRPV1, TRPV4, and NaV1.5

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.

Exploring lipid signaling in plant physiology: From cellular membranes to environmental adaptation

Lipids have evolved as versatile signaling molecules that regulate a variety of physiological processes in plants. Convincing evidence highlights their critical role as mediators in a wide range of plant processes required for survival, growth, development, and responses to environmental conditions such as water availability, temperature changes, salt, pests, and diseases. Understanding lipid signaling as a critical process has helped us expand our understanding of plant biology by explaining how plants sense and respond to environmental cues. Lipid signaling pathways constitute a complex network of lipids, enzymes, and receptors that coordinate important cellular responses and stressing plant biology's changing and adaptable traits. Plant lipid signaling involves a wide range of lipid classes, including phospholipids, sphingolipids, oxylipins, and sterols, each of which contributes differently to cellular communication and control. These lipids function not only as structural components, but also as bioactive molecules that transfer signals. The mechanisms entail the production of lipid mediators and their detection by particular receptors, which frequently trigger downstream cascades that affect gene expression, cellular functions, and overall plant growth. This review looks into lipid signaling in plant physiology, giving an in-depth look and emphasizing its critical function as a master regulator of vital activities.

Cell type-specific and subcellular expression of phospholipid phosphatase-related proteins to modulate lyso-phosphatidic acid synaptic signaling in the developing and adult CNS

Lysophosphatidic acid (LPA) is a bioactive phospholipid that participates in critical processes in neural development and adult brain function and is implicated in various pathophysiological conditions. Along with its six well-characterized receptors, atypical regulators of LPA signaling have also been suggested, including phospholipid phosphatase-related proteins (PLPPRs). PLPPRs have been mostly studied in the developing brain where they control LPA-dependent axon guidance, cortical network hyperexcitability, and glutamatergic neurotransmission. PLPPR4 and PLPPR3 represent two closely related proteins reported to localize predominantly in dendrites and axons, respectively, and differ in their developmental expression patterns. Herein, we have revised the expression patterns of PLPPRs in the cerebellum, dorsal and ventral hippocampus, prefrontal cortex (PFC), nucleus accumbens, and striatum during development and in the adult using quantitative PCR. Expression patterns of Plppr2,4 and 5 were consistent with previous studies, whereas Plppr3 and Plppr1 exhibited a unique expression profile in nucleus accumbens (NAc) and striatum in later developmental and adult stages, which we verified at the protein level for PLPPR3. To investigate neuron type-specific expression at the single cell level, we developed a bioinformatic tool to analyze recent single-cell RNA-sequencing data in the cerebral cortex and hippocampus of adult mice. Our analysis revealed a widespread but also selective adult neuron-type expression with higher expression levels of Plppr3, Plppr1, and Plppr5 in GABAergic and Plppr4 and Plppr2 in glutamatergic neurons. PLPPR4 has been identified as a post-synaptic modulator of LPA levels in glutamatergic synapses operating via an uptake mechanism, to control LPA-dependent cortical network hyperexcitability. Using subcellular fractionation experiments, we found that both PLPPR4 and PLPPR3 are co-expressed in adult synaptosomal membranes. Furthermore, flow cytometry experiments in HEK293 cells showed comparable LPA uptake by PLPPR4 and PLPPR3, whereas PLPRR3, but not PLPPR4, induced also uptake of monoacylglycerol, the dephosphorylation product of LPA. We propose that synaptic LPA may be subject to both pre-synaptic and post-synaptic mechanisms of regulation by PLPPRs in addition to LPARs in developing and adult synapses.

Phosphatidic acid is an endogenous negative regulator of PIEZO2 channels and mechanical sensitivity

Mechanosensitive PIEZO2 ion channels play roles in touch, proprioception, and inflammatory pain. Currently, there are no small molecule inhibitors that selectively inhibit PIEZO2 over PIEZO1. The TMEM120A protein was shown to inhibit PIEZO2 while leaving PIEZO1 unaffected. Here we find that TMEM120A expression elevates cellular levels of phosphatidic acid and lysophosphatidic acid (LPA), aligning with its structural resemblance to lipid-modifying enzymes. Intracellular application of phosphatidic acid or LPA inhibits PIEZO2 but not PIEZO1 activity. Extended extracellular exposure to the non-hydrolyzable phosphatidic acid and LPA analog carbocyclic phosphatidic acid (ccPA) also inhibits PIEZO2. Optogenetic activation of phospholipase D (PLD), a signaling enzyme that generates phosphatidic acid, inhibits PIEZO2 but not PIEZO1. Conversely, inhibiting PLD leads to increased PIEZO2 activity and increased mechanical sensitivity in mice in behavioral experiments. These findings unveil lipid regulators that selectively target PIEZO2 over PIEZO1, and identify the PLD pathway as a regulator of PIEZO2 activity.

The Role of Lysophospholipid Metabolites LPC and LPA in the Pathogenesis of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition characterized by persistent respiratory symptoms and airflow limitation. While there are some available treatment options, the effectiveness of treatment varies depending on individual differences and the phenotypes of the disease. Therefore, exploring or identifying potential therapeutic targets for COPD is urgently needed. In recent years, there has been growing evidence showing that lysophospholipids, namely lysophosphatidylcholine (LPC) and lysophosphatidic acid (LPA), can play a significant role in the pathogenesis of COPD. Exploring the metabolism of lysophospholipids holds promise for understanding the underlying mechanism of COPD development and developing novel strategies for COPD treatment. This review primarily concentrates on the involvement and signaling pathways of LPC and LPA in the development and progression of COPD. Furthermore, we reviewed their associations with clinical manifestations, phenotypes, and prognosis within the COPD context and discussed the potential of the pivotal signaling molecules as viable therapeutic targets for COPD treatment.

The Emerging Role of LPA as an Oncometabolite

Lysophosphatidic acid (LPA) is a phospholipid that displays potent signalling activities that are regulated in both an autocrine and paracrine manner. It can be found both extra- and intracellularly, where it interacts with different receptors to activate signalling pathways that regulate a plethora of cellular processes, including mitosis, proliferation and migration. LPA metabolism is complex, and its biosynthesis and catabolism are under tight control to ensure proper LPA levels in the body. In cancer patient specimens, LPA levels are frequently higher compared to those of healthy individuals and often correlate with poor responses and more aggressive disease. Accordingly, LPA, through promoting cancer cell migration and invasion, enhances the metastasis and dissemination of tumour cells. In this review, we summarise the role of LPA in the regulation of critical aspects of tumour biology and further discuss the available pre-clinical and clinical evidence regarding the feasibility and efficacy of targeting LPA metabolism for effective anticancer therapy.

Effects of Regulating Hippo and Wnt on the Development and Fate Differentiation of Bovine Embryo

The improvement of in vitro embryo development is a gateway to enhance the output of assisted reproductive technologies. The Wnt and Hippo signaling pathways are crucial for the early development of bovine embryos. This study investigated the development of bovine embryos under the influence of a Hippo signaling agonist (LPA) and a Wnt signaling inhibitor (DKK1). In this current study, embryos produced in vitro were cultured in media supplemented with LPA and DKK1. We comprehensively analyzed the impact of LPA and DKK1 on various developmental parameters of the bovine embryo, such as blastocyst formation, differential cell counts, YAP fluorescence intensity and apoptosis rate. Furthermore, single-cell RNA sequencing (scRNA-seq) was employed to elucidate the in vitro embryonic development. Our results revealed that LPA and DKK1 improved the blastocyst developmental potential, total cells, trophectoderm (TE) cells and YAP fluorescence intensity and decreased the apoptosis rate of bovine embryos. A total of 1203 genes exhibited differential expression between the control and LPA/DKK1-treated (LD) groups, with 577 genes upregulated and 626 genes downregulated. KEGG pathway analysis revealed significant enrichment of differentially expressed genes (DEGs) associated with TGF-beta signaling, Wnt signaling, apoptosis, Hippo signaling and other critical developmental pathways. Our study shows the role of LPA and DKK1 in embryonic differentiation and embryo establishment of pregnancy. These findings should be helpful for further unraveling the precise contributions of the Hippo and Wnt pathways in bovine trophoblast formation, thus advancing our comprehension of early bovine embryo development.

Phosphatidic acid is an endogenous negative regulator of PIEZO2 channels and mechanical sensitivity

Mechanosensitive PIEZO2 ion channels play roles in touch, proprioception, and inflammatory pain. Currently, there are no small molecule inhibitors that selectively inhibit PIEZO2 over PIEZO1. The TMEM120A protein was shown to inhibit PIEZO2 while leaving PIEZO1 unaffected. Here we find that TMEM120A expression elevates cellular levels of phosphatidic acid and lysophosphatidic acid (LPA), aligning with its structural resemblance to lipid-modifying enzymes. Intracellular application of phosphatidic acid or LPA inhibited PIEZO2, but not PIEZO1 activity. Extended extracellular exposure to the non-hydrolyzable phosphatidic acid and LPA analogue carbocyclic phosphatidic acid (ccPA) also inhibited PIEZO2. Optogenetic activation of phospholipase D (PLD), a signaling enzyme that generates phosphatidic acid, inhibited PIEZO2, but not PIEZO1. Conversely, inhibiting PLD led to increased PIEZO2 activity and increased mechanical sensitivity in mice in behavioral experiments. These findings unveil lipid regulators that selectively target PIEZO2 over PIEZO1, and identify the PLD pathway as a regulator of PIEZO2 activity.

Discovery of a Novel Orally Active, Selective LPA Receptor Type 1 Antagonist, 4-(4-(2-Isopropylphenyl)-4-((2-methoxy-4-methylphenyl)carbamoyl)piperidin-1-yl)-4-oxobutanoic Acid, with a Distinct Molecular Scaffold

Lysophosphatidic acid receptor 1 (LPAR1) antagonists show promise as potentially novel antifibrotic treatments. In a human LPAR1 β-arrestin recruitment-based high-throughput screening campaign, we identified urea 19 as a hit with a LPAR1 IC50 value of 5.0 μM. Hit-to-lead activities revealed that one of the urea nitrogen atoms can be replaced by carbon and establish the corresponding phenylacetic amide as a lead structure for further optimization. Medicinal chemistry efforts led to the discovery of piperidine 18 as a potent and selective LPAR1 antagonist with oral activity in a mouse model of LPA-induced skin vascular leakage. The molecular scaffold of 18 shares no obvious structural similarity with any other LPAR1 antagonist disclosed so far.

Functional modulation of lysophosphatidic acid type 2 G-protein coupled receptor facilitates alveolar bone formation

Lipid biosynthesis is recently studied its functions in a range of cellular physiology including differentiation and regeneration. However, it still remains to be elucidated in its precise function. To reveal this, we evaluated the roles of lysophosphatidic acid (LPA) signaling in alveolar bone formation using the LPA type 2 receptor (LPAR2) antagonist AMG-35 (Amgen Compound 35) using tooth loss without periodontal disease model which would be caused by trauma and usually requires a dental implant to restore masticatory function. In this study, in vitro cell culture experiments in osteoblasts and periodontal ligament fibroblasts revealed cell type-specific responses, with AMG-35 modulating osteogenic differentiation in osteoblasts in vitro. To confirm the in vivo results, we employed a mouse model of tooth loss without periodontal disease. Five to 10 days after tooth extraction, AMG-35 facilitated bone formation in the tooth root socket as measured by immunohistochemistry for differentiation markers KI67, Osteocalcin, Periostin, RUNX2, transforming growth factor beta 1 (TGF-β1) and SMAD2/3. The increased expression and the localization of these proteins suggest that AMG-35 elicits osteoblast differentiation through TGF-β1 and SMAD2/3 signaling. These results indicate that LPAR2/TGF-β1/SMAD2/3 represents a new signaling pathway in alveolar bone formation and that local application of AMG-35 in traumatic tooth loss can be used to facilitate bone regeneration and healing for further clinical treatment.

Gintonin Alleviates HCl/Ethanol- and Indomethacin-Induced Gastric Ulcers in Mice

Gintonin, newly extracted from ginseng, is a glycoprotein that acts as an exogenous lysophosphatidic acid (LPA) receptor ligand. This study aimed to demonstrate the in vivo preventive effects of gintonin on gastric damage. ICR mice were randomly assigned to five groups: a normal group (received saline, 0.1 mL/10 g, p.o.); a control group (administered 0.3 M HCl/ethanol, 0.1 mL/10 g, p.o.) or indomethacin (30 mg/kg, p.o.); gintonin at two different doses (50 mg/kg or 100 mg/kg, p.o.) with either 0.3 M HCl/ethanol or indomethacin; and a positive control (Ranitidine, 40 mg/kg, p.o.). After gastric ulcer induction, the gastric tissue was examined to calculate the ulcer index. The expression of gastric damage markers, such as tumor necrosis factor (TNF)-α, cyclooxygenase 2 (COX-2), and LPA2 and LPA5 receptors, were measured by Western blotting. Interleukin-6 (IL-6) and prostaglandin E2 (PGE2) levels were measured by enzyme-linked immunosorbent assay. The platelet endothelial cell adhesion molecule (PECAM-1), Evans blue, and occludin levels in gastric tissues were measured using immunofluorescence analysis. Both HCl/ethanol- and indomethacin-induced gastric ulcers showed increased TNF-α, IL-6, Evans blue permeation, and PECAM-1, and decreased COX-2, PGE2, occludin, and LPA5 receptor expression levels. However, oral administration of gintonin alleviated the gastric ulcer index induced by HCl/ethanol and indomethacin in a dose-dependent manner. Gintonin suppressed TNF-α and IL-6 expression, but increased COX-2 expression and PGE2 levels in mouse gastric tissues. Gintonin intake also increased LPA5 receptor expression in mouse gastric tissues. These results indicate that gintonin can play a role in gastric protection against gastric damage induced by HCl/ethanol or indomethacin.

Targeting fatty acid uptake and metabolism in cancer cells: A promising strategy for cancer treatment

Despite scientific development, cancer is still a fatal disease. The development of cancer is thought to be significantly influenced by fatty acids. Several mechanisms that control fatty acid absorption and metabolism are reported to be altered in cancer cells to support their survival. Cancer cells can use de novo synthesis or uptake of extracellular fatty acid if one method is restricted. This factor makes it more difficult to target one pathway while failing to treat the disease properly. Side effects may also arise if several inhibitors simultaneously target many targets. If a viable inhibitor could work on several routes, the number of negative effects might be reduced. Comparative investigations against cell viability have found several potent natural and manmade substances. In this review, we discuss the complex roles that fatty acids play in the development of tumors and the progression of cancer, newly discovered and potentially effective natural and synthetic compounds that block the uptake and metabolism of fatty acids, the adverse side effects that can occur when multiple inhibitors are used to treat cancer, and emerging therapeutic approaches.

Regulation of CD8 T-cell signaling, metabolism, and cytotoxic activity by extracellular lysophosphatidic acid

Lysophosphatidic acid (LPA) is an endogenous bioactive lipid that is produced extracellularly and signals to cells via cognate LPA receptors, which are G-protein coupled receptors (GPCRs). Mature lymphocytes in mice and humans express three LPA receptors, LPA2 , LPA5, and LPA6 , and work from our group has determined that LPA5 signaling by T lymphocytes inhibits specific antigen-receptor signaling pathways that ultimately impair lymphocyte activation, proliferation, and function. In this review, we discuss previous and ongoing work characterizing the ability of an LPA-LPA5 axis to serve as a peripheral immunological tolerance mechanism that restrains adaptive immunity but is subverted during settings of chronic inflammation. Specifically, LPA-LPA5 signaling is found to regulate effector cytotoxic CD8 T cells by (at least) two mechanisms: (i) regulating the actin-microtubule cytoskeleton in a manner that impairs immunological synapse formation between an effector CD8 T cell and antigen-specific target cell, thus directly impairing cytotoxic activity, and (ii) shifting T-cell metabolism to depend on fatty-acid oxidation for mitochondrial respiration and reducing metabolic efficiency. The in vivo outcome of LPA5 inhibitory activity impairs CD8 T-cell killing and tumor immunity in mouse models providing impetus to consider LPA5 antagonism for the treatment of malignancies and chronic infections.

Inhibition of autotaxin alleviates pathological features of hepatic encephalopathy at the level of gut-liver-brain axis: an experimental and bioinformatic study

There is accumulating evidence that the circulatory levels of autotaxin (ATX) and lysophosphatidic acid (LPA) are increased in patients with severe liver disease. However, the potential role of the ATX-LPA axis in hepatic encephalopathy (HE) remains unclear. Our study aimed to investigate the role of the ATX-LPA signaling pathway in mice with thioacetamide (TAA) induced acute HE. To show the role of the ATX-LPA axis in the context of HE, we first measured the involvement of ATX-LPA in the pathogenesis of TAA-induced acute HE. Then, we compared the potential effects of ATX inhibitor (HA130) on astrocyte responses at in vitro and gut-liver-brain axis at in vivo levels. The inflammatory chemokine (C-C motif) ligand 3 was significantly increased in the hyperammonemic condition and could be prevented by ATX inhibition in astrocytes at in vitro level. Further statistical tests revealed that plasma and tissue pro-inflammatory cytokines were inhibited by HA130 in mice. Furthermore, the stage of HE was significantly improved by HA130. The most surprising result was that HA130 alleviated immune infiltrating cells in the liver and intestine and decreased mucus-secreting cells in the intestine. Further analysis showed that the levels of liver enzymes in serum were significantly decreased in response to ATX inhibition. Surprisingly, our data indicated that HA130 could recover permeabilization of the blood-brain barrier, neuroinflammation, and recognition memory. Besides that, we found that the changes of Interleukin-1 (IL-1) and aquaporin-4 (AQP4) in HE might have a connection with the glymphatic system based on bioinformatics analyses. Taken together, our data showed that the ATX-LPA axis contributes to the pathogenesis of HE and that inhibition of ATX improves HE.

Thrombogenesis-associated genetic determinants as predictors of thromboembolism and prognosis in cervical cancer

Venous thromboembolism (VTE) is a leading cause of death among cancer patients. Khorana score (KS) is the most studied tool to predict cancer-related VTE, however, it exerts poor sensitivity. Several single-nucleotide polymorphisms (SNPs) have been associated with VTE risk in the general population, but whether they are predictors of cancer-related VTE is a matter of discussion. Compared to other solid tumours, little is known about VTE in the setting of cervical cancer (CC) and whether thrombogenesis-related polymorphisms could be valuable biomarkers in patients with this neoplasia. This study aims to analyse the effect of VTE occurrence on the prognosis of CC patients, explore the predictive capability of KS and the impact of thrombogenesis-related polymorphisms on CC-related VTE incidence and patients' prognosis regardless of VTE. A profile of eight SNPs was evaluated. A retrospective hospital-based cohort study was conducted with 400 CC patients under chemoradiotherapy. SNP genotyping was carried on by using TaqMan® Allelic Discrimination methodology. Time to VTE occurrence and overall survival were the two measures of clinical outcome evaluated. The results indicated that VTE occurrence (8.5%) had a significant impact on the patient's survival (log-rank test, P < 0.001). KS showed poor performance (KS ≥ 3, χ², P = 0.191). PROCR rs10747514 and RGS7 rs2502448 were significantly associated with the risk of CC-related VTE development (P = 0.021 and P = 0.006, respectively) and represented valuable prognostic biomarkers regardless of VTE (P = 0.004 and P = 0.010, respectively). Thus, thrombogenesis-related genetic polymorphisms may constitute valuable biomarkers among CC patients allowing a more personalized clinical intervention.

Transplantation-based screen identifies inducers of muscle progenitor cell engraftment across vertebrate species

Stem cell transplantation presents a potentially curative strategy for genetic disorders of skeletal muscle, but this approach is limited by the deleterious effects of cell expansion in vitro and consequent poor engraftment efficiency. In an effort to overcome this limitation, we sought to identify molecular signals that enhance the myogenic activity of cultured muscle progenitors. Here, we report the development and application of a cross-species small-molecule screening platform employing zebrafish and mice, which enables rapid, direct evaluation of the effects of chemical compounds on the engraftment of transplanted muscle precursor cells. Using this system, we screened a library of bioactive lipids to discriminate those that could increase myogenic engraftment in vivo in zebrafish and mice. This effort identified two lipids, lysophosphatidic acid and niflumic acid, both linked to the activation of intracellular calcium-ion flux, which showed conserved, dose-dependent, and synergistic effects in promoting muscle engraftment across these vertebrate species.

Is fat the future for saving sight? Bioactive lipids and their impact on glaucoma

Glaucoma is characterized by a continuous loss of retinal ganglion cells. The cause of glaucoma is associated with an increase in intraocular pressure (IOP), but the underlying pathophysiology is diverse and, in most cases, unknown. There is an indisputable unmet need to identify new pathways involved in glaucoma pathogenesis. Increasing evidence suggests that bioactive lipids may be critical in the development and progression of glaucoma. Preclinical and clinical bioactive lipid targets exist and are being developed. In this review, we aim to shed light on the potential of bioactive lipids for the prevention, diagnosis, prognosis, and treatment of glaucoma by asking the question "is fat the future for saving sight".

Functions and interaction of plant lipid signalling under abiotic stresses

Lipids are the primary form of energy storage and a major component of plasma membranes, which form the interface between the cell and the extracellular environment. Several lipids - including phosphoinositide, phosphatidic acid, sphingolipids, lysophospholipids, oxylipins, and free fatty acids - also serve as substrates for the generation of signalling molecules. Abiotic stresses, such as drought and temperature stress, are known to affect plant growth. In addition, abiotic stresses can activate certain lipid-dependent signalling pathways that control the expression of stress-responsive genes and contribute to plant stress adaptation. Many studies have focused either on the enzymatic production and metabolism of lipids, or on the mechanisms of abiotic stress response. However, there is little information regarding the roles of plant lipids in plant responses to abiotic stress. In this review, we describe the metabolism of plant lipids and discuss their involvement in plant responses to abiotic stress. As such, this review provides crucial background for further research on the interactions between plant lipids and abiotic stress.

The Autotaxin-LPA Axis Emerges as a Novel Regulator of Smooth Muscle Cell Phenotypic Modulation during Intimal Hyperplasia

Neointimal hyperplasia is characterized by a loss of the contractile phenotype of vascular smooth muscle cells (VSMCs). Our group has recently shown that VSMC proliferation and migration are mediated by lysophosphatidic acid (LPA) during restenosis, but the role of autotaxin (ATX; lysophospholipase D), which produces LPA, remains unclear. Endothelial denudation of the mouse carotid artery was performed to induce neointimal hyperplasia, and the extent of damage caused by the ATX-LPA axis was assessed in VSMCs. We observed the upregulation of ATX activity (p < 0.0002) in the injured carotid artery using an AR2 probe fluorescence assay. Further, the tissue carotid LPA levels were elevated 2.7-fold in carotid vessels, augmenting neointimal hyperplasia. We used an electrical cell-substrate impedance sensor (ECIS) to measure VSMC proliferation and migration. Treatment with an ATX inhibitor (PF8380) or LPA receptor inhibitor (Ki16425) attenuated VSMC proliferation (extracellular signal-regulated kinases) activity and migration in response to recombinant ATX. Indeed, PF8380 treatment rescued the aggravated post-wire injury neointima formation of carotid arteries. The upregulation of ATX following vessel injury leads to LPA production in VSMCs, favoring restenosis. Our observations suggest that inhibition of the ATX-LPA axis could be therapeutically targeted in restenosis to minimize VSMC phenotypic modulation and inflammation after vascular injury.

In Vitro Animal Model for Estimating the Time since Death with Attention to Early Postmortem Stage

Estimating the postmortem interval (PMI) has remained the subject of investigations in forensic medicine for many years. Every kind of death results in changes in metabolites in body tissues and fluids due to lack of oxygen, altered circulation, enzymatic reactions, cellular degradation, and cessation of anabolic production of metabolites. Metabolic changes may provide markers determining the time since death, which is challenging in current analytical and observation-based methods. The study includes metabolomics analysis of blood with the use of an animal model to determine the biochemical changes following death. LC-MS is used to fingerprint postmortem porcine blood. Metabolites, significantly changing in blood after death, are selected and identified using univariate statistics. Fifty-one significant metabolites are found to help estimate the time since death in the early postmortem stage. Hypoxanthine, lactic acid, histidine, and lysophosphatidic acids are found as the most promising markers in estimating an early postmortem stage. Selected lysophosphatidylcholines are also found as significantly increased in blood with postmortal time, but their practical utility as PMI indicators can be limited due to a relatively low increasing rate. The findings demonstrate the great potential of LC-MS-based metabolomics in determining the PMI due to sudden death and provide an experimental basis for applying this attitude in investigating various mechanisms of death. As we assume, our study is also one of the first in which the porcine animal model is used to establish PMI metabolomics biomarkers.

Plasma membrane phospholipid phosphatase-related proteins as pleiotropic regulators of neuron growth and excitability

Neuronal plasma membrane proteins are essential for integrating cell extrinsic and cell intrinsic signals to orchestrate neuronal differentiation, growth and plasticity in the developing and adult nervous system. Here, we shed light on the family of plasma membrane proteins phospholipid phosphatase-related proteins (PLPPRs) (alternative name, PRGs; plasticity-related genes) that fine-tune neuronal growth and synaptic transmission in the central nervous system. Several studies uncovered essential functions of PLPPRs in filopodia formation, axon guidance and branching during nervous system development and regeneration, as well as in the control of dendritic spine number and excitability. Loss of PLPPR expression in knockout mice increases susceptibility to seizures, and results in defects in sensory information processing, development of psychiatric disorders, stress-related behaviors and abnormal social interaction. However, the exact function of PLPPRs in the context of neurological diseases is largely unclear. Although initially described as active lysophosphatidic acid (LPA) ecto-phosphatases that regulate the levels of this extracellular bioactive lipid, PLPPRs lack catalytic activity against LPA. Nevertheless, they emerge as atypical LPA modulators, by regulating LPA mediated signaling processes. In this review, we summarize the effects of this protein family on cellular morphology, generation and maintenance of cellular protrusions as well as highlight their known neuronal functions and phenotypes of KO mice. We discuss the molecular mechanisms of PLPPRs including the deployment of phospholipids, actin-cytoskeleton and small GTPase signaling pathways, with a focus on identifying gaps in our knowledge to stimulate interest in this understudied protein family.

A type IV Autotaxin inhibitor ameliorates acute liver injury and nonalcoholic steatohepatitis

The lysophosphatidic acid (LPA) signaling axis is an important but rather underexplored pathway in liver disease. LPA is predominantly produced by Autotaxin (ATX) that has gained significant attention with an impressive number of ATX inhibitors (type I-IV) reported. Here, we evaluated the therapeutic potential of a (yet unexplored) type IV inhibitor, Cpd17, in liver injury. We first confirmed the involvement of the ATX-LPA signaling axis in human and murine diseased livers. Then, we evaluated the effects of Cpd17, in comparison with the classic type I inhibitor PF8380, in vitro, where Cpd17 showed higher efficacy. Thereafter, we characterized the mechanism-of-action of both inhibitors and found that Cpd17 was more potent in inhibiting RhoA-mediated cytoskeletal remodeling, and phosphorylation of MAPK/ERK and AKT/PKB. Finally, the therapeutic potential of Cpd17 was investigated in CCl4 -induced acute liver injury and diet-induced nonalcoholic steatohepatitis, demonstrating an excellent potential of Cpd17 in reducing liver injury in both disease models in vivo. We conclude that ATX inhibition, by type IV inhibitor in particular, has an excellent potential for clinical application in liver diseases.

Effect of BBT-877, a novel inhibitor of ATX, on a mouse model of type 1 diabetic nephropathy

Diabetic nephropathy (DN) is one of the common microvascular complications of diabetes. Autotaxin (ATX) is an enzyme with lysophospholipase D activity, producing lysophosphatidic acid (LPA). LPA signaling has been implicated in renal fibrosis, thereby inducing renal dysfunction. BBT-877 is an orally administered small molecule inhibitor of ATX. However, its effect on DN has not been studied so far. In this study, we investigated the effect of BBT-877, a novel inhibitor of ATX, on the pathogenesis of DN in a mouse model of streptozotocin (STZ)-induced diabetes. BBT-877 treatment significantly reduced albuminuria, albumin-to-creatinine ratio (ACR), neutrophil gelatinase-associated lipocalin (NGAL), and glomerular volume compared to the STZ-vehicle group. Interestingly, BBT-877 treatment attenuated hyperglycemia and dyslipidemia in STZ-induced diabetes mice. In the liver, the expression levels of β-oxidation-related genes such as PPAR α and CPT1 were significantly decreased in STZ-induced diabetic mice. However, this effect was reversed by BBT-877 treatment. BBT-877 treatment also suppressed mRNA levels of pro-inflammatory cytokines IL-6, MCP-1, and TNF-α and protein levels of fibrotic factors (TGF-β, fibronectin, CTGF, and collagen type Ι alpha Ι (COL1A1)) in the kidneys of STZ-induced diabetic mice. In conclusion, our results indicate that BBT-877 is effective in preventing the pathogenesis of DN by reducing systemic blood glucose levels and inhibiting inflammation and fibrosis in the renal tissue of diabetes mice. These novel findings suggest that inhibition of ATX may be a potential therapeutic target for DN.

Autotaxin/Lysophosphatidic Acid Axis: From Bone Biology to Bone Disorders

Lysophosphatidic acid (LPA) is a natural bioactive phospholipid with pleiotropic activities affecting multiple tissues, including bone. LPA exerts its biological functions by binding to G-protein coupled LPA receptors (LPA_1-6) to stimulate cell migration, proliferation, and survival. It is largely produced by autotaxin (ATX), a secreted enzyme with lysophospholipase D activity that converts lysophosphatidylcholine (LPC) into active LPA. Beyond its enzymatic activity, ATX serves as a docking molecule facilitating the efficient delivery of LPA to its specific cell surface receptors. Thus, LPA effects are the result of local production by ATX in a given tissue or cell type. As a consequence, the ATX/LPA axis should be considered as an entity to better understand their roles in physiology and pathophysiology and to propose novel therapeutic strategies. Herein, we provide not only an extensive overview of the relevance of the ATX/LPA axis in bone cell commitment and differentiation, skeletal development, and bone disorders, but also discuss new working hypotheses emerging from the interplay of ATX/LPA with well-established signaling pathways regulating bone mass.

Elevated level of lysophosphatidic acid among patients with HNF1B mutations and its role in RCAD syndrome: a multiomic study

INTRODUCTION

Patients with hepatocyte nuclear factor-1 beta (HNF1B) mutations present a variable phenotype with two main symptoms: maturity onset diabetes of the young (MODY) and polycystic kidney disease (PKD).

OBJECTIVES

Identification of serum metabolites specific for HNF1Bmut and evaluation of their role in disease pathogenesis.

METHODS

We recruited patients with HNF1Bmut (N = 10), HNF1Amut (N = 10), PKD: non-dialyzed and dialyzed (N = 8 and N = 13); and healthy controls (N = 12). Serum fingerprinting was performed by LC-QTOF-MS. Selected metabolite was validated by ELISA (enzyme-linked immunosorbent assay) measurements and then biologically connected with HNF1B by in silico analysis. HepG2 were stimulated with lysophosphatidic acid (LPA) and HNF1B gene was knocked down (kd) by small interfering RNA. Transcriptomic analysis with microarrays and western blot measurements were performed.

RESULTS

Serum levels of six metabolites including: arachidonic acid, hydroxyeicosatetraenoic acid, linoleamide and three LPA (18:1, 18:2 and 20:4), had AUC (the area under the curve) > 0.9 (HNF1Bmut vs comparative groups). The increased level of LPA was confirmed by ELISA measurements. In HepG2^HNF1Bkd cells LPA stimulation lead to downregulation of many pathways associated with cell cycle, lipid metabolism, and upregulation of steroid hormone metabolism and Wnt signaling. Also, increased intracellular protein level of autotaxin was detected in the cells. GSK-3alpha/beta protein level and its phosphorylated ratio were differentially affected by LPA stimulation in HNF1Bkd and control cells.

CONCLUSIONS

LPA is elevated in sera of patients with HNF1Bmut. LPA contributes to the pathogenesis of HNF1B-MODY by affecting Wnt/GSK-3 signaling.

Lysophosphatidic acid shifts metabolic and transcriptional landscapes to induce a distinct cellular state in human pluripotent stem cells

Pluripotent stem cells (PSCs) can be maintained in a continuum of cellular states with distinct features. Exogenous lipid supplements can relieve the dependence on de novo lipogenesis and shift global metabolism. However, it is largely unexplored how specific lipid components regulate metabolism and subsequently the pluripotency state. In this study, we report that the metabolic landscape of human PSCs (hPSCs) is shifted by signaling lipid lysophosphatidic acid (LPA), which naturally exists. LPA leads to a distinctive transcriptome profile that is not associated with de novo lipogenesis. Although exogenous lipids such as cholesterol, common free fatty acids, and LPA can affect cellular metabolism, they are not necessary for maintaining primed pluripotency. Instead, LPA induces distinct and reversible phenotypes in cell cycle, morphology, and mitochondria. This study reveals a distinct primed state that could be used to alter cell physiology in hPSCs for basic research and stem cell applications.

Effect of Lysophosphatidic Acid on the Vascular Endothelial Growth Factor Expression in Autotransplanted Mouse Ovaries Encapsulated in Sodium Alginate

Objective: The aim of this study was to evaluate the effect of lysophosphatidic acid (LPA) supplementation during in vitro culture and transplantation of mouse ovaries on the follicular development and expression of vascular endothelial growth factor (VEGF) as an angiogenesis factor at the mRNA and protein levels. Materials and methods: Three weeks old mice ovaries were cultured in the presence and absence of LPA for 24 hours, then they were capsulated in sodium alginate in the presence and absence of LPA as four experimental groups. After transplantation the vaginal smears were performed daily to evaluate the initiation of the estrous cycle. The morphology and follicular distribution were analyzed at the first and fourth estrous cycles using hematoxylin and eosin staining. Then in the groups that showed higher and lower follicular development the immunohistochemistry assay was conducted to identify VEGF protein expression, and the real time RT-PCR was done to analyze the expression of Vegf gene at the first estrus cycle. Results: The large size follicles and also the corpus luteum were prominent in all transplanted groups at fourth estrus cycle in comparison with intact control groups. The statistically lowest percentage of small size follicles and the highest percentages of large size follicles were seen in LPA⁺/LPA^- group (p<0.05). The expression ratio of Vegf to β-actin was significantly higher in this group in comparison with non-LPA treated and intact control groups (p <0.05). Conclusion: LPA as an angiogenesis factor increases the follicular development in transplanted ovaries but it causes early discharge of ovarian reserve.

Transcriptome Profiling of Dysregulated GPCRs Reveals Overlapping Patterns across Psychiatric Disorders and Age-Disease Interactions

G-protein-coupled receptors (GPCRs) play an integral role in the neurobiology of psychiatric disorders. Almost all neurotransmitters involved in psychiatric disorders act through GPCRs, and GPCRs are the most common targets of therapeutic drugs currently used in the treatment of psychiatric disorders. However, the roles of GPCRs in the etiology and pathophysiology of psychiatric disorders are not fully understood. Using publically available datasets, we performed a comprehensive analysis of the transcriptomic signatures of G-protein-linked signaling across the major psychiatric disorders: autism spectrum disorder (ASD), schizophrenia (SCZ), bipolar disorder (BP), and major depressive disorder (MDD). We also used the BrainSpan transcriptomic dataset of the developing human brain to examine whether GPCRs that exhibit chronological age-associated expressions have a higher tendency to be dysregulated in psychiatric disorders than age-independent GPCRs. We found that most GPCR genes were differentially expressed in the four disorders and that the GPCR superfamily as a gene cluster was overrepresented in the four disorders. We also identified a greater amplitude of gene expression changes in GPCRs than other gene families in the four psychiatric disorders. Further, dysregulated GPCRs overlapped across the four psychiatric disorders, with SCZ exhibiting the highest overlap with the three other disorders. Finally, the results revealed a greater tendency of age-associated GPCRs to be dysregulated in ASD than random GPCRs. Our results substantiate the central role of GPCR signaling pathways in the etiology and pathophysiology of psychiatric disorders. Furthermore, our study suggests that common GPCRs' signaling may mediate distinct phenotypic presentations across psychiatric disorders. Consequently, targeting these GPCRs could serve as a common therapeutic strategy to treat specific clinical symptoms across psychiatric disorders.

The novel ORFV protein ORFV113 activates LPA-p38 signaling

Viruses have evolved mechanisms to subvert critical cellular signaling pathways that regulate a wide range of cellular functions, including cell differentiation, proliferation and chemotaxis, and innate immune responses. Here, we describe a novel ORFV protein, ORFV113, that interacts with the G protein-coupled receptor Lysophosphatidic acid receptor 1 (LPA1). Consistent with its interaction with LPA1, ORFV113 enhances p38 kinase phosphorylation in ORFV infected cells in vitro and in vivo, and in cells transiently expressing ORFV113 or treated with soluble ORFV113. Infection of cells with virus lacking ORFV113 (OV-IA82Δ113) significantly decreased p38 phosphorylation and viral plaque size. Infection of cells with ORFV in the presence of a p38 kinase inhibitor markedly diminished ORFV replication, highlighting importance of p38 signaling during ORFV infection. ORFV113 enhancement of p38 activation was prevented in cells in which LPA1 expression was knocked down and in cells treated with LPA1 inhibitor. Infection of sheep with OV-IA82Δ113 led to a strikingly attenuated disease phenotype, indicating that ORFV113 is a major virulence determinant in the natural host. Notably, ORFV113 represents the first viral protein that modulates p38 signaling via interaction with LPA1 receptor.

Maternal serum lipidomics identifies lysophosphatidic acid as a predictor of small for gestational age neonates

To discover lipidomic alterations during pregnancy in mothers who subsequently delivered small for gestational age (SGA) neonates and identify predictive lipid markers that can help recognize and manage these mothers, we carried out untargeted lipidomics on maternal serum samples collected between 24-28 weeks of gestation. We used a nested case-control study design and serum from mothers who delivered SGA and appropriate for gestational age babies. We applied untargeted lipidomics using mass spectrometry to characterize lipids and discover changes associated with SGA births during pregnancy. Multivariate pattern recognition software Collaborative Laboratory Integrated Reports (CLIR) was used for the post-analytical recognition of range differences in lipid ratios that could differentiate between SGA and control mothers and their integration for complete separation between the two groups. Here, we report changes in lipids from serum collected during pregnancy in mothers who delivered SGA neonates. In contrast to normal pregnancies where lysophosphatidic acid increased over the course of the pregnancy owing to increased activity of lysophospholipase D, we observed a decrease (32%; P = 0.05) of 20:4-lysophosphatidic acid in SGA mothers, which could potentially compromise fetal growth and development. Integration of lipid ratios in an interpretive tool (CLIR) could completely separate SGA mothers from controls demonstrating the power of untargeted lipidomic analyses for identifying novel predictive biomarkers. Additional studies are required for further assessment of the lipid biomarkers identified in this report.

Identification of GOLPH3 Partners in Drosophila Unveils Potential Novel Roles in Tumorigenesis and Neural Disorders

Golgi phosphoprotein 3 (GOLPH3) is a highly conserved peripheral membrane protein localized to the Golgi apparatus and the cytosol. GOLPH3 binding to Golgi membranes depends on phosphatidylinositol 4-phosphate [PI(4)P] and regulates Golgi architecture and vesicle trafficking. GOLPH3 overexpression has been correlated with poor prognosis in several cancers, but the molecular mechanisms that link GOLPH3 to malignant transformation are poorly understood. We recently showed that PI(4)P-GOLPH3 couples membrane trafficking with contractile ring assembly during cytokinesis in dividing Drosophila spermatocytes. Here, we use affinity purification coupled with mass spectrometry (AP-MS) to identify the protein-protein interaction network (interactome) of Drosophila GOLPH3 in testes. Analysis of the GOLPH3 interactome revealed enrichment for proteins involved in vesicle-mediated trafficking, cell proliferation and cytoskeleton dynamics. In particular, we found that dGOLPH3 interacts with the Drosophila orthologs of Fragile X mental retardation protein and Ataxin-2, suggesting a potential role in the pathophysiology of disorders of the nervous system. Our findings suggest novel molecular targets associated with GOLPH3 that might be relevant for therapeutic intervention in cancers and other human diseases.

Lysophosphatidic Acid Regulates Rho Family of GTPases in Lungs

The bio-active lipid, lysophosphatidic acid (LPA) interacts with various lysophosphatidic acid receptors (LPARs) to affect a variety of cellular functions, including proliferation, differentiation, survival, migration, morphogenesis and others. The Rho family of small GTPases, is well-known downstream signaling pathways activated by LPA. Among the Rho GTPases, RhoA, Rac1, and Cdc42 are best characterized and LPA-induced activation of the GTPases RhoA, Rac1, and Cdc42 influences a wide range of cellular processes and functions such as cell differentiation, contractile movements, cellular migration, or infiltration. In this review, we will briefly discuss the interplay between LPA and each of these three Rho family proteins, summarizing the main interactions between them. Our discussion will focus mainly on their interplay within lung endothelial and epithelial cells, drawing attention to how these interactions may contribute to pro-inflammatory processes.

Generation of an Lpar1-EGFP Fusion Knock-in Transgenic Mouse Line

Lysophosphatidic acid (LPA) is a lysophospholipid that acts as an extracellular signal through the activation of cognate G protein-coupled receptors (GPCRs). There are six known LPA receptors (LPA1-6). The first such receptor, LPA1, was identified in the embryonic brain and has been studied extensively for gene expression throughout the body, including through studies of receptor-null mice. However, identifying receptor protein expression in situ and in vivo within living cells and tissues has been difficult because of biologically low receptor expression and variable antibody specificity. To visualize native LPA1 receptor expression in situ, we generated a knock-in mouse produced by homologous recombination in murine embryonic stem (ES) cells to replace a wildtype Lpar1 allele with a mutant allele created by in-frame fusion of EGFP to the 4th exon of Lpar1 (Lpar1-EGFP knock-in allele). Homozygous knock-in mice appeared normal and the expected mendelian ratios of knock-in allele transmission were present in females and males. Histological assessments of the fetal and adult central nervous system (CNS) demonstrated expression patterns that were consistent with prior in situ hybridization studies. This new mouse line will be useful for studies of LPA1 in the developing and adult CNS, as well as other tissues, and for receptor assessments in living tissues and disease models.

Decidualized endometrial stromal cells present with altered androgen response in PCOS

Hyperandrogenic women with PCOS show disrupted decidualization (DE) and placentation. Dihydrotestosterone (DHT) is reported to enhance DE in non-PCOS endometrial stromal cells (eSC_Ctrl); however, this has not been assessed in PCOS cells (eSC_PCOS). Therefore, we studied the transcriptome profile of non-decidualized (non-DE) and DE eSCs from women with PCOS and Ctrl in response to short-term estradiol (E2) and/or progesterone (P4) exposure with/without (±) DHT. The non-DE eSCs were subjected to E2 ± DHT treatment, whereas the DE (0.5 mM 8-Br-cAMP, 96 h) eSCs were post-treated with E2 and P4 ± DHT, and RNA-sequenced. Validation was performed by immunofluorescence and immunohistochemistry. The results showed that, regardless of treatment, the PCOS and Ctrl samples clustered separately. The comparison of DE vs. non-DE eSC_PCOS without DHT revealed PCOS-specific differentially expressed genes (DEGs) involved in mitochondrial function and progesterone signaling. When further adding DHT, we detected altered responses for lysophosphatidic acid (LPA), inflammation, and androgen signaling. Overall, the results highlight an underlying defect in decidualized eSC_PCOS, present with or without DHT exposure, and possibly linked to the altered pregnancy outcomes. We also report novel factors which elucidate the mechanisms of endometrial dysfunction in PCOS.

Cyclophosphamide Exposure Causes Long-Term Detrimental Effect of Oocytes Developmental Competence Through Affecting the Epigenetic Modification and Maternal Factors' Transcription During Oocyte Growth

Cyclophosphamide (CTX) is widely used in various cancer therapies and in immunosuppression, and patients can still have babies after CTX chemotherapy. CTX directly causes primordial follicle loss with overactivation and DNA damage-induced apoptosis. Previous studies have shown that maternal exposure to CTX before conception increases the incidence of birth abnormalities and alters the methylation of genes in the oocytes of offspring. Mice were treated with a single dose of CTX (100 mg/kg) at post-natal day 21 and sacrificed 47 days later when primordial follicles surviving chemotherapy developed to the antral stage. Acute DNA damage and acceleration of the activation of primordial follicles after CTX treatment were repaired within several days, but the remaining follicle numbers remarkably decrease. Although partial surviving primordial follicle were developed to mature oocyte, oocyte quality hemostasis was impaired exhibiting aberrant meiosis progression, abnormal spindle and aneuploidy, mitochondrial dysfunction and increased endoplasmic reticulum stress. Thereafter, embryo development competency significantly decreased with fewer blastocyst formation after CTX exposure. CTX treatment resulted in alteration of DNA methylations and histone modifications in fully grown GV oocytes. Single-cell RNA-seq revealed CTX treatment suppressed multiple maternal genes’ transcription including many methyltransferases and maternal factor YAP1, which probably accounts for low quality of CTX-repaired oocyte. In vitro addition of lysophosphatidic acid (LPA) to embryo culture media to promote YAP1 nuclear localization improved CTX-repaired embryo developmental competence. This study provides evidence for the consistent toxic effect of CTX exposure during follicle development, and provide a new mechanism and new insights into future clinical interventions for fertility preservation.

Lysophosphatidic acid (LPA) receptor modulators: Structural features and recent development

Lysophosphatidic acid (LPA) activates six LPA receptors (LPAR_1-6) and regulates various cellular activities such as cell proliferation, cytoprotection, and wound healing. Many studies elucidated the pathological outcomes of LPA are due to the alteration in signaling pathways, which include migration and invasion of cancer cells, fibrosis, atherosclerosis, and inflammation. Current pathophysiological research on LPA and its receptors provides a means that LPA receptors are new therapeutic targets for disorders associated with LPA. Various chemical modulators are developed and are under investigation to treat a wide range of pathological complications. This review summarizes the physiological and pathological roles of LPA signaling, development of various LPA modulators, their structural features, patents, and their clinical outcomes.

Lysophosphatidic Acid Accelerates Bovine In Vitro-Produced Blastocyst Formation through the Hippo/YAP Pathway

The segregation of trophectoderm (TE) and inner cell mass in early embryos is driven primarily by the transcription factor CDX2. The signals that trigger CDX2 activation are, however, less clear. In mouse embryos, the Hippo-YAP signaling pathway is important for the activation of CDX2 expression; it is less clear whether this relationship is conserved in other mammals. Lysophosphatidic acid (LPA) has been reported to increase YAP levels by inhibiting its degradation. In this study, we cultured bovine embryos in the presence of LPA and examined changes in gene and protein expression. LPA was found to accelerate the onset of blastocyst formation on days 5 and 6, without changing the TE/inner cell mass ratio. We further observed that the expression of TAZ and TEAD4 was up-regulated, and YAP was overexpressed, in LPA-treated day 6 embryos. However, LPA-induced up-regulation of CDX2 expression was only evident in day 8 embryos. Overall, our data suggest that the Hippo signaling pathway is involved in the initiation of bovine blastocyst formation, but does not affect the cell lineage constitution of blastocysts.

Fight Hard or Die Trying: Current Status of Lipid Signaling during Plant-Pathogen Interaction

Plant diseases pose a substantial threat to food availability, accessibility, and security as they account for economic losses of nearly $300 billion on a global scale. Although various strategies exist to reduce the impact of diseases, they can introduce harmful chemicals to the food chain and have an impact on the environment. Therefore, it is necessary to understand and exploit the plants' immune systems to control the spread of pathogens and enable sustainable agriculture. Recently, growing pieces of evidence suggest a functional myriad of lipids to be involved in providing structural integrity, intracellular and extracellular signal transduction mediators to substantial cross-kingdom cell signaling at the host-pathogen interface. Furthermore, some pathogens recognize or exchange plant lipid-derived signals to identify an appropriate host or development, whereas others activate defense-related gene expression. Typically, the membrane serves as a reservoir of lipids. The set of lipids involved in plant-pathogen interaction includes fatty acids, oxylipins, phospholipids, glycolipids, glycerolipids, sphingolipids, and sterols. Overall, lipid signals influence plant-pathogen interactions at various levels ranging from the communication of virulence factors to the activation and implementation of host plant immune defenses. The current review aims to summarize the progress made in recent years regarding the involvement of lipids in plant-pathogen interaction and their crucial role in signal transduction.

CG11426 gene product negatively regulates glial population size in the Drosophila eye imaginal disc

Glial cells play essential roles in the nervous system. Although glial populations are tightly regulated, the mechanisms regulating the population size remain poorly understood. Since Drosophila glial cells are similar to the human counterparts in their functions and shapes, rendering them an excellent model system to understand the human glia biology. Lipid phosphate phosphatases (LPPs) are important for regulating bioactive lipids. In Drosophila, there are three known LPP-encoding genes: wunen, wunen-2, and lazaro. The wunens are important for germ cell migration and survival and septate junction formation during tracheal development. Lazaro is involved in phototransduction. In the present study, we characterized a novel Drosophila LPP-encoding gene, CG11426. Suppression of CG11426 increased glial cell number in the eye imaginal disc during larval development, while ectopic CG11426 expression decreased it. Both types of mutation also caused defects in axon projection to the optic lobe in larval eye-brain complexes. Moreover, CG11426 promoted apoptosis via inhibiting ERK signaling in the eye imaginal disc. Taken together, these findings demonstrated that CG11426 gene product negatively regulates ERK signaling to promote apoptosis for proper maintenance of the glial population in the developing eye disc.

O-GlcNAc modification of MYPT1 modulates lysophosphatidic acid-induced cell contraction in fibroblasts

Thousands of proteins have been found to be modified by O-GlcNAc, a common glycosylation modification of serine and threonine residues throughout the cytosol and nucleus. O-GlcNAc is enzymatically added and removed from proteins, making it a potential dynamic regulator of cell signaling. However, compared with other posttranslational modifications like phosphorylation, relatively few O-GlcNAc-regulated pathways have been discovered and biochemically characterized. We previously discovered one such pathway, where O-GlcNAc controls the contraction of fibroblasts initiated by the signaling lipid sphingosine-1-phosphate. Specifically, we found that O-GlcNAc modification of the phosphatase MYPT1 maintains its activity, resulting in dephosphorylation and deactivation of the myosin light chain of the actinomyosin complex. Another signaling lipid that leads to contraction of fibroblasts is lysophosphatidic acid, and this signaling pathway also converges on MYPT1 and actinomyosin. We therefore rationalized that O-GlcNAc would also control this pathway. Here, we used a combination of small molecule inhibitors, 2D and 3D cell cultures, and biochemistry to confirm our hypothesis. Specifically, we found that O-GlcNAc levels control the sensitivity of mouse and primary human dermal fibroblasts to lysophosphatidic acid–induced contraction in culture and the phosphorylation of MLC and that MYPT1 O-GlcNAc modification is responsible. These findings further solidify the importance of O-GlcNAc in regulating the biology of fibroblasts in response to procontractile stimuli.

Lysophosphatidic Acid and IL-6 Trans-signaling Interact via YAP/TAZ and STAT3 Signaling Pathways in Human Trabecular Meshwork Cells

Purpose

Lysophosphatidic acid (LPA) and soluble interleukin-6 receptor (sIL6R) are elevated in primary open angle glaucoma (POAG). LPA and IL6 modulate in response to biomechanical stimuli and converge on similar fibrotic phenotypes. Thus, we determined whether LPA and IL6 trans-signaling (IL6/sIL6R) interact via Yes-associated protein (YAP)/Transcriptional coactivator with a PDZ-binding motif (TAZ) or Signal transducer and activator of transcription 3 (STAT3) pathways in human trabecular meshwork (hTM) cells.

Methods

Confluent primary hTM cells were serum starved for 24 hours, and treated with vehicle, LPA (20 µM), IL6 (100 ng/mL)/sIL6R (200 ng/mL), or both (LPA + IL6/sIL6R) for 24 hours, with or without a YAP inhibitor (verteporfin; 2 µM) or STAT3 inhibitor (2 µM). Expression of key receptors and ligands, signaling mediators, actomyosin machinery, cell contractility, and extracellular matrix (ECM) targets of both signaling pathways was determined by immunocytochemistry, RT-qPCR, and Western blotting.

Results

LPA and IL6 trans-signaling coupling overexpressed/activated receptors and ligands, glycoprotein-130, IL6, and autotaxin; signaling mediators, YAP, TAZ, Pan-TEAD, and phosphorylated STAT3 (pSTAT3); actomyosin and contractile machinery components, myosin light chain 2 (MLC2), phosphorylated MLC2, rho-associated protein kinase 1, filamentous actin, and α-smooth muscle actin; and fibrotic ECM proteins, collagen I and IV, fibronectin, laminin, cysteine-rich angiogenic inducer 61, and connective tissue growth factor in hTM cells; mostly beyond LPA or IL6 trans-signaling alone. Verteporfin inhibited YAP, TAZ, and pSTAT3, with concomitant abrogation of aforementioned fibrotic targets; the STAT3 inhibitor was only partially effective.

Conclusions

These data suggest synergistic crosstalk between LPA and IL6 trans-signaling, mediated by YAP, TAZ, and pSTAT3. By completely inhibiting these mediators, verteporfin may be more efficacious in ameliorating LPA and/or IL6 trans-signaling–induced ocular hypertensive phenotypes in hTM cells.

Lysophosphatidic acid (LPA)-antibody (504B3) engagement detected by interferometry identifies off-target binding

Background

Lysophosphatidic acid (LPA) is a bioactive lysophospholipid that acts through its six cognate G protein-coupled receptors. As a family, lysophospholipids have already produced medicines (e.g., sphingosine 1-phosphate) as is being pursued for LPA through the use of specific antibodies that reduce ligand availability.

Methods

The binding properties of a commercially available, reportedly specific, monoclonal LPA antibody named 504B3 that is related to the clinical candidate Lpathomab/LT3015 were reexamined using a free solution assay (FSA) measured in a compensated interferometric reader (CIR).

Results

Measurement of 504B3 binding properties with an FSA-CIR approach revealed similar binding affinities for 504B3 against LPA as well as the non-LPA lipids, phosphatidic acid (PA) and lysophosphatidylcholine (LPC).

Conclusions

Antibody binding specificity and sensitivity, particularly involving lipid ligands, can be assessed in solution and without labels using FSA-CIR. These findings could affect interpretations of both current and past basic and clinical studies employing 504B3 and related anti-LPA antibodies.

Gintonin mitigates experimental autoimmune encephalomyelitis by stabilization of Nrf2 signaling via stimulation of lysophosphatidic acid receptors

Gintonin (GT), a glycolipoprotein fraction isolated from ginseng, exerts neuroprotective effects in models of neurodegenerative diseases such as Alzheimer's disease. However, the in vivo role of GT in multiple sclerosis (MS) has not been clearly resolved. We investigated the effect of GT in myelin oligodendrocyte glycoprotein (MOG_35-55)-induced experimental autoimmune encephalomyelitis (EAE), an animal model of MS. GT alleviated behavioral symptoms of EAE associated with reduced demyelination, diminished infiltration and activation of immune cells (microglia and macrophage), and decreased expression of inflammatory mediators in the spinal cord of the EAE group compared to that of the sham group. GT reduced the percentages of CD4⁺/IFN-γ⁺ (Th1) and CD4⁺/IL-17⁺ (Th17) cells but increased the population of CD4⁺/CD25⁺/Foxp3⁺ (Treg) cells in the spinal cord, in agreement with altered mRNA expression of IFN-γ, IL-17, and TGF-ß in the spinal cord in concordance with mitigated blood-brain barrier disruption. The underlying mechanism is related to inhibition of the ERK and p38 mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) pathways and the stabilization of nuclear factor erythroid 2-related factor 2 (Nrf2) via increased expression of lysophosphatidic acid receptor (LPAR) 1-3. Impressively, these beneficial effects of GT were completely neutralized by inhibiting LPARs with Ki16425, a LPAR1/3 antagonist. Our results strongly suggest that GT may be able to alleviate EAE due to its anti-inflammatory and antioxidant activities through LPARs. Therefore, GT is a potential therapeutic option for treating autoimmune disorders including MS.

Role of lysophosphatidic acid and its receptors in health and disease: novel therapeutic strategies

Lysophosphatidic acid (LPA) is an abundant bioactive phospholipid, with multiple functions both in development and in pathological conditions. Here, we review the literature about the differential signaling of LPA through its specific receptors, which makes this lipid a versatile signaling molecule. This differential signaling is important for understanding how this molecule can have such diverse effects during central nervous system development and angiogenesis; and also, how it can act as a powerful mediator of pathological conditions, such as neuropathic pain, neurodegenerative diseases, and cancer progression. Ultimately, we review the preclinical and clinical uses of Autotaxin, LPA, and its receptors as therapeutic targets, approaching the most recent data of promising molecules modulating both LPA production and signaling. This review aims to summarize the most update knowledge about the mechanisms of LPA production and signaling in order to understand its biological functions in the central nervous system both in health and disease.

Expanding the clinical and metabolic phenotype of DPM2 deficient congenital disorders of glycosylation

Pathogenic alterations in the DPM2 gene have been previously described in patients with hypotonia, progressive muscle weakness, absent psychomotor development, intractable seizures, and early death. We identified biallelic DPM2 variants in a 23-year-old male with truncal hypotonia, hypertonicity, congenital heart defects, intellectual disability, and generalized muscle wasting. His clinical presentation was much less severe than that of the three previously described patients. This is the second report on this ultra-rare disorder. Here we review the characteristics of previously reported individuals with a defect in the DPM complex while expanding the clinical phenotype of DPM2-Congenital Disorders of Glycosylation. In addition, we offer further insights into the pathomechanism of DPM2-CDG disorder by introducing glycomics and lipidomics analysis.

Lysophosphatidic acid mediated PI3K/Akt activation contributed to esophageal squamous cell cancer progression

Lysophosphatidic acid (LPA) and its G-protein-coupled receptors (Lpar1-Lpar6) mediate a plethora of activities associated with cancer growth and progression. However, there is no systematic study about whether and how LPA promotes esophageal squamous cell carcinoma (ESCC). Here, we show that autotaxin (ATX), a primary LPA-producing enzyme, is highly expressed in ESCC, and overexpressed ATX is associated with the poor outcome of ESCC patients. Meanwhile, the expression of Lpar1 was much higher in ESCC cells compared with Het-1a (human esophagus normal epithelial cells). Functional experiments showed that LPA remarkably increased the proliferation and migration of ESCC cells. Furthermore, Lpar1 knockdown abolished the effect of LPA on ESCC cell proliferation and migration. Mechanistic studies revealed that LPA promoted ESCC cell lines proliferation and migration through PI3K/Akt pathway. Treatment of KYSE30 cell xenografts with Lpar1 inhibitor BMS-986020 significantly repressed tumor growth. Our results shed light on the important role of LPA in ESCC, and Lpar1 might be a potential treatment target for ESCC.