The lipid kinase PIP5K1C regulates pain signaling and sensitization.
Ontology highlight
ABSTRACT:
SUBMITTER: Wright BD
PROVIDER: S-EPMC4074510 | biostudies-literature | 2014 May
REPOSITORIES: biostudies-literature
Publications
The lipid kinase PIP5K1C regulates pain signaling and sensitization.
Wright Brittany D BD Loo Lipin L Street Sarah E SE Ma Anqi A Taylor-Blake Bonnie B Stashko Michael A MA Jin Jian J Janzen William P WP Frye Stephen V SV Zylka Mark J MJ
Neuron 20140501 4
Numerous pain-producing (pronociceptive) receptors signal via phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis. However, it is currently unknown which lipid kinases generate PIP2 in nociceptive dorsal root ganglia (DRG) neurons and if these kinases regulate pronociceptive receptor signaling. Here, we found that phosphatidylinositol 4-phosphate 5 kinase type 1C (PIP5K1C) is expressed at higher levels than any other PIP5K and, based on experiments with Pip5k1c(+/-) mice, generates at least ...[more]
Similar Datasets
Project description:Somatosensory neurons mediate responses to diverse mechanical stimuli, from innocuous touch to noxious pain. While recent studies have identified distinct populations of A mechanonociceptors (AMs) that are required for mechanical pain, the molecular underpinnings of mechanonociception remain unknown. Here, we show that the bioactive lipid sphingosine 1-phosphate (S1P) and S1P Receptor 3 (S1PR3) are critical regulators of acute mechanonociception. Genetic or pharmacological ablation of S1PR3, or blockade of S1P production, significantly impaired the behavioral response to noxious mechanical stimuli, with no effect on responses to innocuous touch or thermal stimuli. These effects are mediated by fast-conducting A mechanonociceptors, which displayed a significant decrease in mechanosensitivity in S1PR3 mutant mice. We show that S1PR3 signaling tunes mechanonociceptor excitability via modulation of KCNQ2/3 channels. Our findings define a new role for S1PR3 in regulating neuronal excitability and establish the importance of S1P/S1PR3 signaling in the setting of mechanical pain thresholds.
| S-EPMC5896955 | biostudies-literature
Project description:Neutrophils are important in innate immunity and acute inflammatory responses. However, the regulation of their recruitment to sites of inflammation has not been well characterized. Here, we investigated the kinase PIP5K1C and showed that PIP5K1C deficiency impaired neutrophil recruitment because of an adhesion defect. PIP5K1C regulated the adhesion through facilitating RhoA GTPase and integrin activation by chemoattractants. Integrins could induce polarization of an isoform of PIP5K1C, PIP5K1C-90, in neutrophils through intracellular vesicle transport independently of exogenous chemoattractant. PIP5K1C-90 polarization was required for polarized RhoA activation at uropods and provided an initial directional cue for neutrophil polarization on the endothelium. Importantly, the polarization was also required for circumventing the inhibition of lamellipodium formation by RhoA so that neutrophils could form leading edges required for transendothelial migration. Because integrins are not known to regulate neutrophil polarization, our study revealed a previously underappreciated role of integrin signaling in neutrophil regulation.
| S-EPMC2947797 | biostudies-literature
Project description:BACKGROUND:Nociceptive sensitization is a tissue damage response whereby sensory neurons near damaged tissue enhance their responsiveness to external stimuli. This sensitization manifests as allodynia (aversive withdrawal to previously nonnoxious stimuli) and/or hyperalgesia (exaggerated responsiveness to noxious stimuli). Although some factors mediating nociceptive sensitization are known, inadequacies of current analgesic drugs have prompted a search for additional targets. RESULTS:Here we use a Drosophila model of thermal nociceptive sensitization to show that Hedgehog (Hh) signaling is required for both thermal allodynia and hyperalgesia following ultraviolet irradiation (UV)-induced tissue damage. Sensitization does not appear to result from developmental changes in the differentiation or arborization of nociceptive sensory neurons. Genetic analysis shows that Hh signaling acts in parallel to tumor necrosis factor (TNF) signaling to mediate allodynia and that distinct transient receptor potential (TRP) channels mediate allodynia and hyperalgesia downstream of these pathways. We also demonstrate a role for Hh in analgesic signaling in mammals. Intrathecal or peripheral administration of cyclopamine (CP), a specific inhibitor of Sonic Hedgehog signaling, blocked the development of analgesic tolerance to morphine (MS) or morphine antinociception in standard assays of inflammatory pain in rats and synergistically augmented and sustained morphine analgesia in assays of neuropathic pain. CONCLUSIONS:We demonstrate a novel physiological role for Hh signaling, which has not previously been implicated in nociception. Our results also identify new potential therapeutic targets for pain treatment.
| S-EPMC3262399 | biostudies-literature
Project description:Phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks) regulate a variety of cellular processes, including signaling through G protein-coupled receptors (GPCRs), endocytosis, exocytosis, and cell migration. These lipid kinases synthesize phosphatidylinositol 4,5-bisphosphate (PIP2) from phosphatidylinositol 4-phosphate [PI(4)P]. Because small-molecule inhibitors of these lipid kinases did not exist, molecular and genetic approaches were predominantly used to study PIP5K1 regulation of these cellular processes. Moreover, standard radioisotope-based lipid kinase assays cannot be easily adapted for high-throughput screening. Here, we report a novel, high-throughput, microfluidic mobility shift assay to identify inhibitors of PIP5K1C. This assay uses fluorescently labeled phosphatidylinositol 4-phosphate as the substrate and recombinant human PIP5K1C. Our assay exhibited high reproducibility, had a calculated adenosine triphosphate Michaelis constant (Km) of 15 µM, performed with z' values >0.7, and was used to screen a kinase-focused library of ~4700 compounds. From this screen, we identified several potent inhibitors of PIP5K1C, including UNC3230, a compound that we recently found can reduce nociceptive sensitization in animal models of chronic pain. This novel assay will allow continued drug discovery efforts for PIP5K1C and can be adapted easily to screen additional lipid kinases.
| S-EPMC4610143 | biostudies-literature
Project description:Enhancer of zeste homolog 2 (EZH2) regulates stem cells renewal, maintenance, and differentiation into different cell lineages including neuron. Changes in intracellular Ca(2+) concentration play a critical role in the differentiation of neurons. However, whether EZH2 modulates intracellular Ca(2+) signaling in regulating neuronal differentiation from human mesenchymal stem cells (hMSCs) still remains unclear. When hMSCs were treated with a Ca(2+) chelator or a PLC inhibitor to block IP(3)-mediated Ca(2+) signaling, neuronal differentiation was disrupted. EZH2 bound to the promoter region of PIP5K1C to suppress its transcription in proliferating hMSCs. Interestingly, knockdown of EZH2 enhanced the expression of PIP5K1C, which in turn increased the amount of PI(4,5)P(2), a precursor of IP(3), and resulted in increasing the intracellular Ca(2+) level, suggesting that EZH2 negatively regulates intracellular Ca(2+) through suppression of PIP5K1C. Knockdown of EZH2 also enhanced hMSCs differentiation into functional neuron both in vitro and in vivo. In contrast, knockdown of PIP5K1C significantly reduced PI(4,5)P(2) contents and intracellular Ca(2+) release in EZH2-silenced cells and resulted in the disruption of neuronal differentiation from hMSCs. Here, we provide the first evidence to demonstrate that after induction to neuronal differentiation, decreased EZH2 activates the expression of PIP5K1C to evoke intracellular Ca(2+) signaling, which leads hMSCs to differentiate into functional neuron lineage. Activation of intracellular Ca(2+) signaling by repressing or knocking down EZH2 might be a potential strategy to promote neuronal differentiation from hMSCs for application to neurological dysfunction diseases.
| S-EPMC3059014 | biostudies-literature
Project description:BackgroundThe gene encoding phosphatidylinositol-4-phosphate 5-kinase (PIP5K1C) has been recently implicated in pain regulation. Interestingly, a recent cross-tissue and cross-phenotypic epigenetic analysis identified the same gene in alcohol use disorder (AUD). Given the high comorbidity between AUD and chronic pain, we hypothesized that genetic variation in PIP5K1C might contribute to susceptibility to AUD.MethodsWe conducted a case-control association study of genetic variants in PIP5K1C. Association analyses of 16 common PIP5K1C single nucleotide polymorphisms (SNPs) were conducted in cases and controls of African (427 cases and 137 controls) and European ancestry (488 cases and 324 controls) using standard methods. In addition, given the prominent role of the opioid system in pain signaling, we investigated the effects of acute alcohol exposure on PIP5K1C expression in humanized transgenic mice for the μ-opioid receptor that included the OPRM1 A118G polymorphism, a widely used mouse model to study analgesic response to opioids in pain. PIP5K1C expression was measured in the thalamus and basolateral amygdala (BLA) in mice after short-term administration (single 2 g/kg dose) of alcohol or saline using immunohistochemistry and analyzed by 2-way analysis of variance.ResultsIn the case-control association study using an NIAAA discovery sample, 8 SNPs in PIP5K1C were significantly associated with AUD in the African ancestry (AA) group (p < 0.05 after correction; rs4807493, rs10405681, rs2074957, rs10432303, rs8109485, rs1476592, rs10419980, and rs4432372). However, a replication analysis using an independent sample (N = 3,801) found no significant associations after correction for multiple testing. In the humanized transgenic mouse model with the OPRM1 polymorphism, PIP5K1C expression was significantly different between alcohol and saline-treated mice, regardless of genotype, in both the thalamus (p < 0.05) and BLA (p < 0.01).ConclusionsOur discovery sample shows that genetic variants in PIP5K1C are associated with AUD in the AA group, and acute alcohol exposure leads to up-regulation of PIP5K1C, potentially explaining a mechanism underlying the increased risk for chronic pain conditions in individuals with AUD.
| S-EPMC6134400 | biostudies-literature
Project description:Research backgroundThe role of osteocytes in maintaining bone mass has been progressively emphasized. Pip5k1c is the most critical isoform among PIP5KIs, which can regulate cytoskeleton, biomembrane, and Ca2+ release of cells and participate in many processes, such as cell adhesion, differentiation, and apoptosis. However, its expression and function in osteocytes are still unclear.Materials and methodsTo determine the function of Pip5k1c in osteocytes, the expression of Pip5k1c in osteocytes was deleted by breeding the 10-kb mouse Dmp1-Cre transgenic mice with the Pip5k1cfl/fl mice. Bone histomorphometry, micro-computerized tomography analysis, immunofluorescence staining and western blotting were used to determine the effects of Pip5k1c loss on bone mass. In vitro, we explored the mechanism by siRNA knockdown of Pip5k1c in MLO-Y4 cells.ResultsPip5k1c expression was decreased in osteocytes in senescent and osteoporotic tissues both in humans and mice. Loss of Pip5k1c in osteocytes led to a low bone mass in long bones and spines and impaired biomechanical properties in femur, without changes in calvariae. The loss of Pip5k1c resulted in the reduction of the protein level of type 1 collagen in tibiae and MLO-Y4 cells. Osteocyte Pip5k1c loss reduced the osteoblast and bone formation rate with high expression of sclerostin, impacting the osteoclast activities at the same time. Moreover, Pip5k1c loss in osteocytes reduced expression of focal adhesion proteins and promoted apoptosis.ConclusionOur studies demonstrate the critical role and mechanism of Pip5k1c in osteocytes in regulating bone remodeling.The translational potential of this articleOsteocyte has been considered to a key role in regulating bone homeostasis. The present study has demonstrated that the significance of Pip5k1c in bone homeostasis by regulating the expression of collagen, sclerostin and focal adhesion expression, which provided a possible therapeutic target against human metabolic bone disease.
| S-EPMC10943313 | biostudies-literature
Project description:ObjectiveNonalcoholic fatty liver disease (NAFLD), defined by excessive lipid storage in hepatocytes, has recently emerged as a leading global cause of chronic liver disease. The aim of this study was to examine the role of STE20-type protein kinase TAOK3, which has previously been shown to associate with hepatic lipid droplets, in the initiation and aggravation of human NAFLD.MethodsThe correlation between TAOK3 mRNA expression and the severity of NAFLD was investigated in liver biopsies from 62 individuals. In immortalized human hepatocytes, intracellular fat deposition, lipid metabolism, and oxidative and endoplasmic reticulum stress were analyzed when TAOK3 was overexpressed or knocked down by small interfering RNA. Subcellular localization of TAOK3 was characterized in human and mouse hepatocytes by immunofluorescence microscopy.ResultsWe found that the TAOK3 transcript levels in human liver biopsies were positively correlated with the key lesions of NAFLD (i.e., hepatic steatosis, inflammation, and ballooning). Overexpression of TAOK3 in cultured human hepatocytes exacerbated lipid storage by inhibiting β-oxidation and triacylglycerol secretion while enhancing lipid synthesis. Conversely, silencing of TAOK3 attenuated lipid deposition in human hepatocytes by stimulating mitochondrial fatty acid oxidation and triacylglycerol efflux while suppressing lipogenesis. We also found aggravated or decreased oxidative/endoplasmic reticulum stress in human hepatocytes with increased or reduced TAOK3 levels, respectively. The subcellular localization of TAOK3 in human and mouse hepatocytes was confined to intracellular lipid droplets.ConclusionsThis study provides the first evidence that hepatic lipid droplet-coating kinase TAOK3 is a critical regulatory node controlling liver lipotoxicity and susceptibility to NAFLD.
| S-EPMC8567304 | biostudies-literature
Project description:Although PIKFYVE phosphoinositide kinase inhibitors can selectively eliminate PIKFYVE-dependent human cancer cells in vitro and in vivo, the basis for this selectivity has remained elusive. Here we show that the sensitivity of cells to the PIKFYVE inhibitor WX8 is not linked to PIKFYVE expression, macroautophagic/autophagic flux, the BRAFV600E mutation, or ambiguous inhibitor specificity. PIKFYVE dependence results from a deficiency in the PIP5K1C phosphoinositide kinase, an enzyme required for conversion of phosphatidylinositol-4-phosphate (PtdIns4P) into phosphatidylinositol-4,5-bisphosphate (PtdIns[4,5]P2/PIP2), a phosphoinositide associated with lysosome homeostasis, endosome trafficking, and autophagy. PtdIns(4,5)P2 is produced via two independent pathways. One requires PIP5K1C; the other requires PIKFYVE and PIP4K2C to convert PtdIns3P into PtdIns(4,5)P2. In PIKFYVE-dependent cells, low concentrations of WX8 specifically inhibit PIKFYVE in situ, thereby increasing the level of its substrate PtdIns3P while suppressing PtdIns(4,5)P2 synthesis and inhibiting lysosome function and cell proliferation. At higher concentrations, WX8 inhibits both PIKFYVE and PIP4K2C in situ, which amplifies these effects to further disrupt autophagy and induce cell death. WX8 did not alter PtdIns4P levels. Consequently, inhibition of PIP5K1C in WX8-resistant cells transformed them into sensitive cells, and overexpression of PIP5K1C in WX8-sensitive cells increased their resistance to WX8. This discovery suggests that PIKFYVE-dependent cancers could be identified clinically by low levels of PIP5K1C and treated with PIKFYVE inhibitors.Abbreviations: DMSO: dimethylsulfoxide; ELISA: enzyme-linked immunosorbent assay; LC3-I: microtubule associated protein light chain 3-I; LC3-II: microtubule associated protein light chain 3-II; MS: mass spectrometry; PtdIns: phosphatidylinositol; PtdIns3P: PtdIns-3-phosphate; PtdIns4P: PtdIns-4-phosphate; PtdIns5P: PtdIns-5-phosphate; PtdIns(3,5)P2: PtdIns-3,5-bisphosphate; PtdIns(4,5)P2/PIP2: PtdIns-4,5-bisphosphate; PtdIns(3,4,5)P3/PIP3: PtdIns-3,4,5-trisphosphate; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PI4KA: phosphatidylinositol 4-kinase alpha; PI4KB: phosphatidylinositol 4-kinase beta; PI4K2A: phosphatidylinositol 4-kinase type 2 alpha; PI4K2B: phosphatidylinositol 4-kinase type 2 beta; PIP4K2A: phosphatidylinositol-5-phosphate 4-kinase type 2 alpha; PIP4K2B: phosphatidylinositol-5-phosphate 4-kinase type 2 beta; PIP4K2C: phosphatidylinositol-5-phosphate 4-kinase type 2 gamma; PIP5K1A: phosphatidylinositol-4-phosphate 5-kinase type 1 alpha; PIP5K1B: phosphatidylinositol-4-phosphate 5-kinase type 1 beta; PIP5K1C: phosphatidylinositol-4-phosphate 5-kinase type 1 gamma; WX8: 1H-indole-3-carbaldehyde (4-anilino-6-[4-morpholinyl]-1,3,5-triazin-2-yl)hydrazone.
| S-EPMC10392749 | biostudies-literature
Project description:In many patients, the sympathetic nervous system supports pain and other features of complex regional pain syndrome (CRPS). Accumulating evidence suggests that interleukin (IL)-6 also plays a role in CRPS, and that catecholamines stimulate production of IL-6 in several tissues. We hypothesized that norepinephrine acting through specific adrenergic receptors expressed on keratinocytes stimulates the production of IL-6 and leads to nociceptive sensitization in a rat tibial fracture/cast model of CRPS. Our approach involved catecholamine depletion using 6-hydroxydopamine or, alternatively, guanethidine, to explore sympathetic contributions. Both agents substantially reduced nociceptive sensitization and selectively reduced the production of IL-6 in skin. Antagonism of IL-6 signaling using TB-2-081 also reduced sensitization in this model. Experiments using a rat keratinocyte cell line demonstrated relatively high levels of ?2-adrenergic receptor (?2-AR) expression. Stimulation of this receptor greatly enhanced IL-6 expression when compared to the expression of IL-1?, tumor necrosis factor (TNF)-?, or nerve growth factor. Stimulation of the cells also promoted phosphorylation of the mitogen-activated protein kinases P38, extracellular signal-regulated kinase, and c-Jun amino-terminal kinase. Based on these in vitro results, we returned to animal testing and observed that the selective ?2-AR antagonist butoxamine reduced nociceptive sensitization in the CRPS model, and that local injection of the selective ?2-AR agonist terbutaline resulted in mechanical allodynia and the production of IL-6 in the cells of the skin. No increases in IL-1?, TNF-?, or nerve growth factor levels were seen, however. These data suggest that in CRPS, norepinephrine released from sympathetic nerve terminals stimulates ?2-ARs expressed on epidermal keratinocytes, resulting in local IL-6 production, and ultimately, pain sensitization.
| S-EPMC3713848 | biostudies-literature