Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 17 de 17
Filter
Add more filters










Publication year range
1.
Mar Drugs ; 20(9)2022 Aug 31.
Article in English | MEDLINE | ID: mdl-36135748

ABSTRACT

N-methyl-D-aspartate (NMDA) receptors play a critical role in activity-dependent dendritic arborization, spinogenesis, and synapse formation by stimulating calcium-dependent signaling pathways. Previously, we have shown that brevetoxin 2 (PbTx-2), a voltage-gated sodium channel (VGSC) activator, produces a concentration-dependent increase in intracellular sodium [Na+]I and increases NMDA receptor (NMDAR) open probabilities and NMDA-induced calcium (Ca2+) influxes. The objective of this study is to elucidate the downstream signaling mechanisms by which the sodium channel activator PbTx-2 influences neuronal morphology in murine cerebrocortical neurons. PbTx-2 and NMDA triggered distinct Ca2+-influx pathways, both of which involved the NMDA receptor 2B (GluN2B). PbTx-2-induced neurite outgrowth in day in vitro 1 (DIV-1) neurons required the small Rho GTPase Rac1 and was inhibited by both a PAK1 inhibitor and a PAK1 siRNA. PbTx-2 exposure increased the phosphorylation of PAK1 at Thr-212. At DIV-5, PbTx-2 induced increases in dendritic protrusion density, p-cofilin levels, and F-actin throughout the dendritic arbor and soma. Moreover, PbTx-2 increased miniature excitatory post-synaptic currents (mEPSCs). These data suggest that the stimulation of neurite outgrowth, spinogenesis, and synapse formation produced by PbTx-2 are mediated by GluN2B and PAK1 signaling.


Subject(s)
Neurons , Receptors, N-Methyl-D-Aspartate , p21-Activated Kinases , Actin Depolymerizing Factors/metabolism , Actins/metabolism , Animals , Calcium/metabolism , Marine Toxins , Mice , N-Methylaspartate , Neuronal Outgrowth , Neurons/drug effects , Neurons/metabolism , Oxocins , RNA, Small Interfering/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Sodium/metabolism , Sodium Channel Agonists/metabolism , Voltage-Gated Sodium Channels/metabolism , p21-Activated Kinases/metabolism , rho GTP-Binding Proteins/metabolism
2.
Pharmacol Res ; 183: 106391, 2022 09.
Article in English | MEDLINE | ID: mdl-35944805

ABSTRACT

The 2018 marine pharmacology literature review represents a continuation of the previous 11 reviews of a series initiated in 1998. Preclinical marine pharmacology research during 2018 was performed by investigators in 44 countries and contributed novel pharmacology for 195 marine compounds. The peer-reviewed marine natural products pharmacology literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 53 compounds, 73 compounds which presented antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 69 compounds were reported to show miscellaneous mechanisms of action which may contribute upon further investigation to several pharmacological classes. Thus, in 2018, the preclinical marine natural product pharmacology pipeline continued to report novel pharmacology as well as new lead compounds for the clinical marine pharmaceutical pipeline, which currently contributes to therapeutic strategies for several disease categories.


Subject(s)
Antiprotozoal Agents , Biological Products , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Antifungal Agents , Antiprotozoal Agents/pharmacology , Antiprotozoal Agents/therapeutic use , Antitubercular Agents/pharmacology , Antitubercular Agents/therapeutic use , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Biological Products/pharmacology , Biological Products/therapeutic use , Hypoglycemic Agents/pharmacology , Hypoglycemic Agents/therapeutic use , Marine Biology , Nervous System
3.
ACS Chem Biol ; 17(7): 1910-1923, 2022 07 15.
Article in English | MEDLINE | ID: mdl-35761435

ABSTRACT

Columbamides are chlorinated acyl amide natural products, several of which exhibit cannabinomimetic activity. These compounds were originally discovered from a culture of the filamentous marine cyanobacterium Moorena bouillonii PNG5-198 collected from the coastal waters of Papua New Guinea. The columbamide biosynthetic gene cluster (BGC) had been identified using bioinformatics, but not confirmed by experimental evidence. Here, we report the heterologous expression in Anabaena (Nostoc) PCC 7120 of the 28.5 kb BGC that encodes for columbamide biosynthesis. The production of columbamides in Anabaena is investigated under several different culture conditions, and several new columbamide analogs are identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and nuclear magnetic resonance (NMR). In addition to previously characterized columbamides A, B, and C, new columbamides I-M are produced in these experiments, and the structure of the most abundant monochlorinated analog, columbamide K (11), is fully characterized. The other new columbamide analogs are produced in only small quantities, and structures are proposed based on high-resolution-MS, MS/MS, and 1H NMR data. Overexpression of the pathway's predicted halogenases resulted in increased productions of di- and trichlorinated compounds. The most significant change in production of columbamides in Anabaena is correlated with the concentration of NaCl in the medium.


Subject(s)
Anabaena , Nostoc , Anabaena/chemistry , Anabaena/genetics , Chromatography, Liquid , Multigene Family , Nostoc/genetics , Tandem Mass Spectrometry
4.
J Nat Prod ; 85(3): 562-571, 2022 03 25.
Article in English | MEDLINE | ID: mdl-35239341

ABSTRACT

Voltage-gated sodium channel (VGSC) activators promote neurite outgrowth by augmenting intracellular Na+ concentration ([Na+]i) and upregulating N-methyl-d-aspartate receptor (NMDAR) function. NMDAR activation stimulates calcium (Ca2+) influx and increases brain-derived neurotrophic factor (BDNF) release and activation of tropomyosin receptor kinase B (TrkB) signaling. The BDNF-TrkB pathway has been implicated in activity-dependent neuronal development. We have previously shown that antillatoxin (ATX), a novel lipopeptide isolated from the cyanobacterium Moorea producens, is a VGSC activator that produces an elevation of [Na+]i. Here we address the effect of ATX on the synthesis and release of BDNF and determine the signaling mechanisms by which ATX enhances neurite outgrowth in immature cerebrocortical neurons. ATX treatment produced a concentration-dependent release of BDNF. Acute treatment with ATX also resulted in increased synthesis of BDNF. ATX stimulation of neurite outgrowth was prevented by pretreatment with a TrkB inhibitor or transfection with a dominant-negative Trk-B. The ATX activation of TrkB and Akt was blocked by both a NMDAR antagonist (MK-801) and a VGSC blocker (tetrodotoxin). These results suggest that VGSC activators such as the structurally novel ATX may represent a new pharmacological strategy to promote neuronal plasticity through a NMDAR-BDNF-TrkB-dependent mechanism.


Subject(s)
Brain-Derived Neurotrophic Factor , Tropomyosin , Lipopeptides/pharmacology , Neuronal Outgrowth , Peptides, Cyclic , Receptors, N-Methyl-D-Aspartate/metabolism , Signal Transduction , Tropomyosin/metabolism
5.
Mar Drugs ; 18(7)2020 Jul 21.
Article in English | MEDLINE | ID: mdl-32708077

ABSTRACT

Emerging literature suggests that after a stroke, the peri-infarct region exhibits dynamic changes in excitability. In rodent stroke models, treatments that enhance excitability in the peri-infarct cerebral cortex promote motor recovery. This increase in cortical excitability and plasticity is opposed by increases in tonic GABAergic inhibition in the peri-infarct zone beginning three days after a stroke in a mouse model. Maintenance of a favorable excitatory-inhibitory balance promoting cerebrocortical excitability could potentially improve recovery. Brevetoxin-2 (PbTx-2) is a voltage-gated sodium channel (VGSC) gating modifier that increases intracellular sodium ([Na+]i), upregulates N-methyl-D-aspartate receptor (NMDAR) channel activity and engages downstream calcium (Ca2+) signaling pathways. In immature cerebrocortical neurons, PbTx-2 promoted neuronal structural plasticity by increasing neurite outgrowth, dendritogenesis and synaptogenesis. We hypothesized that PbTx-2 may promote excitability and structural remodeling in the peri-infarct region, leading to improved functional outcomes following a stroke. We tested this hypothesis using epicortical application of PbTx-2 after a photothrombotic stroke in mice. We show that PbTx-2 enhanced the dendritic arborization and synapse density of cortical layer V pyramidal neurons in the peri-infarct cortex. PbTx-2 also produced a robust improvement of motor recovery. These results suggest a novel pharmacologic approach to mimic activity-dependent recovery from stroke.


Subject(s)
Cerebral Cortex/drug effects , Excitatory Amino Acid Agonists/administration & dosage , Marine Toxins/administration & dosage , Motor Activity/drug effects , Neuronal Plasticity/drug effects , Oxocins/administration & dosage , Thrombotic Stroke/drug therapy , Animals , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Cerebral Cortex/metabolism , Cerebral Cortex/pathology , Cerebral Cortex/physiopathology , Disease Models, Animal , Injections , Luminescent Proteins/genetics , Luminescent Proteins/metabolism , Mice, Transgenic , Recovery of Function , Thrombotic Stroke/metabolism , Thrombotic Stroke/pathology , Thrombotic Stroke/physiopathology
6.
Biomed Pharmacother ; 126: 110060, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32145592

ABSTRACT

Arginine vasopressin (AVP) and oxytocin (OT) are nonapeptides that bind to G-protein coupled receptors and influence social behaviors. Consensus mammalian AVP and OT (Leu8-OT) sequences are highly conserved. In marmosets, an amino acid change in the 8th position of the peptide (Pro8-OT) exhibits unique structural and functional properties. There is ∼85 % structural homology between the OT receptor (OTR) and vasopressin 1a receptor (V1aR) resulting in significant cross-reactivity between the ligands and receptors. Chinese hamster ovary (CHO) cells expressing marmoset (mV1aR), macaque (qV1aR), or human vasopressin receptor 1a (hV1aR) were used to assess AVP, Leu8-OT and Pro8-OT pharmacological profiles. To assess activation of Gq, functional assays were performed using Fluo-3 to measure ligand-induced Ca2+ mobilization. In all three V1aR-expressing cell lines, AVP was more potent than the OT ligands. To assess ligand-induced hyperpolarization, FLIPR Membrane Potential (FMP) assays were performed. In all three V1aR lines, AVP was more potent than the OT analogs. The distinctive U-shaped concentration-response curve displayed by AVP may reflect enhanced desensitization of the mV1aR and hV1aR, which is not observed with qV1aR. Evaluation of Ca2+-activated potassium (K+) channels using the inhibitors apamin, paxilline, and TRAM-34 demonstrated that both intermediate and large conductance Ca2+-activated K+ channels contributed to membrane hyperpolarization, with different pharmacological profiles identified for distinct ligand-receptor combinations. Taken together, these data suggest differences in ligand-receptor signaling that may underlie differences in social behavior. Integrative studies of behavior, genetics and ligand-receptor interaction will help elucidate the connection between receptor pharmacology and social behaviors.


Subject(s)
Arginine Vasopressin , Oxytocin , Receptors, Oxytocin/metabolism , Receptors, Vasopressin/metabolism , Animals , Arginine Vasopressin/analogs & derivatives , Arginine Vasopressin/pharmacology , CHO Cells , Calcium/metabolism , Callithrix , Cricetulus , Humans , Ligands , Macaca , Oxytocin/analogs & derivatives , Oxytocin/pharmacology , Potassium Channels, Calcium-Activated/metabolism , Receptors, G-Protein-Coupled/metabolism , Receptors, Oxytocin/genetics , Receptors, Vasopressin/genetics , Social Behavior , Species Specificity
7.
Biomed Pharmacother ; 125: 109832, 2020 May.
Article in English | MEDLINE | ID: mdl-32018219

ABSTRACT

The oxytocin-arginine vasopressin (OT-AVP) ligand-receptor family influences a variety of physiological, behavioral, and social behavioral processes in the brain and periphery. The OT-AVP family is highly conserved in mammals, but recent discoveries have revealed remarkable diversity in OT ligands and receptors in New World Monkeys (NWMs) providing a unique opportunity to assess the effects of genetic variation on pharmacological signatures of peptide ligands. The consensus mammalian OT sequence has leucine in the 8th position (Leu8-OT), whereas a number of NWMs, including the marmoset, have proline in the 8th position (Pro8-OT) resulting in a more rigid tail structure. OT and AVP bind to OT's cognate G-protein coupled receptor (OTR), which couples to various G-proteins (Gi/o, Gq, Gs) to stimulate diverse signaling pathways. CHO cells expressing marmoset (mOTR), titi monkey (tOTR), macaque (qOTR), or human (hOTR) OT receptors were used to compare AVP and OT analog-induced signaling. Assessment of Gq-mediated increase in intracellular calcium (Ca2+) demonstrated that AVP was less potent than OT analogs at OTRs from species whose endogenous ligand is Leu8-OT (tOTR, qOTR, hOTR), relative to Pro8-OT. Likewise, AVP-induced membrane hyperpolarization was less potent at these same OTRs. Evaluation of (Ca2+)-activated potassium (K+) channels using the inhibitors apamin, paxilline, and TRAM-34 demonstrated that both intermediate and large conductance Ca2+-activated K+ channels contributed to membrane hyperpolarization, with different pharmacological profiles identified for distinct ligand-receptor combinations. Understanding more fully the contributions of structure activity relationships for these peptide ligands at vasopressin and OT receptors will help guide the development of OT-mediated therapeutics.


Subject(s)
Arginine Vasopressin/pharmacology , Calcium/metabolism , Membrane Potentials/physiology , Oxytocin/pharmacology , Receptors, Vasopressin/metabolism , Animals , CHO Cells , Callicebus , Callithrix , Cricetinae , Cricetulus , Humans , Macaca , Pertussis Toxin/pharmacology , Receptors, Vasopressin/chemistry , Thapsigargin/pharmacology
8.
J Nat Prod ; 83(3): 617-625, 2020 03 27.
Article in English | MEDLINE | ID: mdl-31916778

ABSTRACT

A thiazole-containing cyclic depsipeptide with 11 amino acid residues, named pagoamide A (1), was isolated from laboratory cultures of a marine Chlorophyte, Derbesia sp. This green algal sample was collected from America Samoa, and pagoamide A was isolated using guidance by MS/MS-based molecular networking. Cultures were grown in a light- and temperature-controlled environment and harvested after several months of growth. The planar structure of pagoamide A (1) was characterized by detailed 1D and 2D NMR experiments along with MS and UV analysis. The absolute configurations of its amino acid residues were determined by advanced Marfey's analysis following chemical hydrolysis and hydrazinolysis reactions. Two of the residues in pagoamide A (1), phenylalanine and serine, each occurred twice in the molecule, once in the d- and once in the l-configuration. The biosynthetic origin of pagoamide A (1) was considered in light of other natural products investigations with coenocytic green algae.


Subject(s)
Biological Products/chemistry , Chlorophyta/chemistry , Depsipeptides/chemistry , American Samoa , Amino Acids , Animals , Biological Products/isolation & purification , Depsipeptides/isolation & purification , Female , Molecular Structure , Rats , Tandem Mass Spectrometry
9.
Mol Neurobiol ; 57(1): 358-371, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31359323

ABSTRACT

MicroRNAs (miRNAs, miRs) are short noncoding RNAs that act to repress expression of proteins from target mRNA transcripts. miRNAs influence many cellular processes including stemness, proliferation, differentiation, maintenance, and survival, and miRNA mutations or misexpression are associated with a variety of disease states. The miR-183 family gene cluster including miR-183, miR-96, and miR-182 is highly conserved among vertebrate and invertebrate organisms, and the miRNAs are coordinately expressed with marked specificity in sensory neurons and sensory epithelial cells. The crucial functions of these miRNAs in normal cellular processes are not yet fully understood, but expectedly dependent upon the transcriptomes of specific cell types at different developmental stages or in various maintenance circumstances. This article provides an overview of evidence supporting roles for miR-183 family members in normal biology of the nervous system, including mechanoreception for auditory and vestibular function, electroreception, chemoreception, photoreception, circadian rhythms, sensory ganglia and pain, and memory formation.


Subject(s)
MicroRNAs/metabolism , Sensation/genetics , Sensory Receptor Cells/metabolism , Animals , Base Sequence , Circadian Rhythm/genetics , Humans , MicroRNAs/genetics , Pain/genetics
10.
Mol Pharmacol ; 95(4): 376-385, 2019 04.
Article in English | MEDLINE | ID: mdl-30739093

ABSTRACT

The neurohypophyseal hormone oxytocin (OT) regulates biologic functions in both peripheral tissues and the central nervous system. In the central nervous system, OT influences social processes, including peer relationships, maternal-infant bonding, and affiliative social relationships. In mammals, the nonapeptide OT structure is highly conserved with leucine in the eighth position (Leu8-OT). In marmosets (Callithrix), a nonsynonymous nucleotide substitution in the OXT gene codes for proline in the eighth residue position (Pro8-OT). OT binds to its cognate G protein-coupled receptor (OTR) and exerts diverse effects, including stimulation (Gs) or inhibition (Gi/o) of adenylyl cyclase, stimulation of potassium channel currents (Gi), and activation of phospholipase C (Gq). Chinese hamster ovary cells expressing marmoset or human oxytocin receptors (mOTRs or hOTRs, respectively) were used to characterize OT signaling. At the mOTR, Pro8-OT was more efficacious than Leu8-OT in measures of Gq activation, with both peptides displaying subnanomolar potencies. At the hOTR, neither the potency nor efficacy of Pro8-OT and Leu8-OT differed with respect to Gq signaling. In both mOTR- and hOTR-expressing cells, Leu8-OT was more potent and modestly more efficacious than Pro8-OT in inducing hyperpolarization. In mOTR cells, Leu8-OT-induced hyperpolarization was modestly inhibited by pretreatment with pertussis toxin (PTX), consistent with a minor role for Gi/o activation; however, the Pro8-OT response in mOTR and hOTR cells was PTX insensitive. These findings are consistent with membrane hyperpolarization being largely mediated by a Gq signaling mechanism leading to Ca2+-dependent activation of K+ channels. Evaluation of the influence of apamin, charybdotoxin, paxilline, and TRAM-34 demonstrated involvement of both intermediate and large conductance Ca2+-activated K+ channels.


Subject(s)
Calcium/metabolism , Leucine/metabolism , Oxytocin/metabolism , Potassium Channels, Calcium-Activated/metabolism , Potassium/metabolism , Proline/metabolism , Receptors, Oxytocin/metabolism , Animals , CHO Cells , Cricetulus , Humans , Membrane Potentials/physiology , Signal Transduction/physiology , Type C Phospholipases/metabolism
11.
Sci Rep ; 8(1): 3569, 2018 02 23.
Article in English | MEDLINE | ID: mdl-29476110

ABSTRACT

Germline mutations in Mir96, one of three co-expressed polycistronic miRNA genes (Mir96, Mir182, Mir183), cause hereditary hearing loss in humans and mice. Transgenic FVB/NCrl- Tg(GFAP-Mir183,Mir96,Mir182)MDW1 mice (Tg1MDW), which overexpress this neurosensory-specific miRNA cluster in the inner ear, were developed as a model system to identify, in the aggregate, target genes and biologic processes regulated by the miR-183 cluster. Histological assessments demonstrate Tg1MDW/1MDW homozygotes have a modest increase in cochlear inner hair cells (IHCs). Affymetrix mRNA microarray data analysis revealed that downregulated genes in P5 Tg1MDW/1MDW cochlea are statistically enriched for evolutionarily conserved predicted miR-96, miR-182 or miR-183 target sites. ABR and DPOAE tests from 18 days to 3 months of age revealed that Tg1MDW/1MDW homozygotes develop progressive neurosensory hearing loss that correlates with histologic assessments showing massive losses of both IHCs and outer hair cells (OHCs). This mammalian miRNA misexpression model demonstrates a potency and specificity of cochlear homeostasis for one of the dozens of endogenously co-expressed, evolutionally conserved, small non-protein coding miRNA families. It should be a valuable tool to predict and elucidate miRNA-regulated genes and integrated functional gene expression networks that significantly influence neurosensory cell differentiation, maturation and homeostasis.


Subject(s)
Hearing Loss, Sensorineural/genetics , MicroRNAs/genetics , Animals , Cell Differentiation/genetics , Disease Models, Animal , Ear, Inner/metabolism , Ear, Inner/pathology , Gene Expression Regulation , Hair Cells, Auditory, Inner/metabolism , Hair Cells, Auditory, Inner/pathology , Hearing Loss, Sensorineural/pathology , Homeostasis/genetics , Humans , Mice , Mice, Transgenic , Microarray Analysis , RNA, Messenger/genetics
12.
J Nat Prod ; 80(8): 2328-2334, 2017 08 25.
Article in English | MEDLINE | ID: mdl-28783331

ABSTRACT

A recent untargeted metabolomics investigation into the chemical profile of 10 organic extracts from cf. Symploca spp. revealed several interesting chemical leads for further natural product drug discovery. Subsequent target-directed isolation efforts with one of these, a Panamanian marine cyanobacterium cf. Symploca sp., yielded a phenethylamide metabolite that terminates in a relatively rare gem-dichlorovinylidene moiety, caracolamide A (1), along with a known isotactic polymethoxy-1-alkene (2). Detailed NMR and HRESIMS analyses were used to determine the structures of these molecules, and compound 1 was confirmed by a three-step synthesis. Pure compound 1 was shown to have in vitro calcium influx and calcium channel oscillation modulatory activity when tested as low as 10 pM using cultured murine cortical neurons, but was not cytotoxic to NCI-H460 human non-small-cell lung cancer cells in vitro (IC50 > 10 µM).


Subject(s)
Cyanobacteria/chemistry , Ion Channels/chemistry , Phenethylamines/chemistry , Carcinoma, Non-Small-Cell Lung , Drug Screening Assays, Antitumor , Humans , Lung Neoplasms , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Phenethylamines/isolation & purification , Phenethylamines/pharmacology
13.
Indian J Hum Genet ; 18(3): 310-9, 2012 Sep.
Article in English | MEDLINE | ID: mdl-23716939

ABSTRACT

BACKGROUND: Orofacial clefts are common worldwide and result from insufficient growth and/or fusion during the genesis of the derivatives of the first pharyngeal arch and the frontonasal prominence. Recent studies in mice carrying conditional and tissue-specific deletions of the human ortholog Dicer1, an RNAse III family member, have highlighted its importance in cell survival, differentiation, proliferation, and morphogenesis. Nevertheless, information regarding Dicer1 and its dependent microRNAs (miRNAs) in mammalian palatogenesis and orofacial development is limited. AIMS: To describe the craniofacial phenotype, gain insight into potential mechanisms underlying the orofacial defects in the Pax2-Cre/Dicer1 CKO mouse, and shed light on the role of Dicer1 in mammalian palatogenesis. MATERIALS AND METHODS: Histological and molecular assays of wild type (WT) and Pax2-Cre/Dicer1(loxP/loxP) (Dicer1 CKO) mice dissected tissues have been performed to characterize and analyze the orofacial dysmorphism in Pax2-Cre/Dicer1(loxP/loxP) mouse. RESULTS: Dicer1 CKO mice exhibit late embryonic lethality and severe craniofacial dysmorphism, including a secondary palatal cleft. Further analysis suggest that Dicer1 deletion neither impacts primary palatal development nor the initial stages of secondary palatal formation. Instead, Dicer1 is implicated in growth, differentiation, mineralization, and survival of cells in the lateral palatal shelves. Histological and molecular analysis demonstrates that secondary palatal development becomes morphologically arrested prior to mineralization around E13.5 with a significant increase in the expression levels of apoptotic markers (P < 0.01). CONCLUSIONS: Pax2-Cre-mediated Dicer1 deletion disrupts lateral palatal outgrowth and bone mineralization during palatal shelf development, therefore providing a mammalian model for investigating the role of miRNA-mediated signaling pathways during palatogenesis.

14.
Dev Dyn ; 240(4): 808-19, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21360794

ABSTRACT

MicroRNAs (miRNAs) post-transcriptionally repress complementary target gene expression and can contribute to cell differentiation. The coordinate expression of miRNA-183 family members (miR-183, miR-96, and miR-182) has been demonstrated in sensory cells of the mouse inner ear and other vertebrate sensory organs. To further examine hair cell miRNA expression in the mouse inner ear, we have analyzed miR-183 family expression in wild type animals and various mutants with defects in neurosensory development. miR-183 family member expression follows neurosensory cell specification, exhibits longitudinal (basal-apical) gradients in maturating cochlear hair cells, and is maintained in sensory neurons and most hair cells into adulthood. Depletion of hair cell miRNAs resulting from Dicer1 conditional knockout (CKO) in Atoh1-Cre transgenic mice leads to more disparate basal-apical gene expression profiles and eventual hair cell loss. Results suggest that hair cell miRNAs subdue cochlear gradient gene expression and are required for hair cell maintenance and survival.


Subject(s)
Cell Differentiation/genetics , Cell Proliferation , Hair Cells, Auditory/physiology , MicroRNAs/physiology , Animals , Cell Survival/genetics , Cell Survival/physiology , Cells, Cultured , Cluster Analysis , Embryo, Mammalian , Gene Expression Profiling , Gene Expression Regulation, Developmental , Hair Cells, Auditory/metabolism , Humans , Mice , Mice, Knockout , MicroRNAs/genetics , MicroRNAs/metabolism , Microarray Analysis , Multigene Family/genetics , Multigene Family/physiology , Neuroepithelial Cells/metabolism , Neuroepithelial Cells/physiology
15.
Dev Biol ; 328(2): 328-41, 2009 Apr 15.
Article in English | MEDLINE | ID: mdl-19389351

ABSTRACT

Inner ear development requires coordinated transformation of a uniform sheet of cells into a labyrinth with multiple cell types. While numerous regulatory proteins have been shown to play critical roles in this process, the regulatory functions of microRNAs (miRNAs) have not been explored. To demonstrate the importance of miRNAs in inner ear development, we generated conditional Dicer knockout mice by the expression of Cre recombinase in the otic placode at E8.5. Otocyst-derived ganglia exhibit rapid neuron-specific miR-124 depletion by E11.5, degeneration by E12.5, and profound defects in subsequent sensory epithelial innervations by E17.5. However, the small and malformed inner ear at E17.5 exhibits residual and graded hair cell-specific miR-183 expression in the three remaining sensory epithelia (posterior crista, utricle, and cochlea) that closely corresponds to the degree of hair cell and sensory epithelium differentiation, and Fgf10 expression required for morphohistogenesis. The highest miR-183 expression is observed in near-normal hair cells of the posterior crista, whereas the reduced utricular macula demonstrates weak miR-183 expression and develops presumptive hair cells with numerous disorganized microvilli instead of ordered stereocilia. The correlation of differential and delayed depletion of mature miRNAs with the derailment of inner ear development demonstrates that miRNAs are crucial for inner ear neurosensory development and neurosensory-dependent morphogenesis.


Subject(s)
DEAD-box RNA Helicases/physiology , Ear, Inner/embryology , Endoribonucleases/physiology , MicroRNAs/biosynthesis , Animals , Cell Differentiation , Cochlea/cytology , Cochlea/embryology , Cochlea/innervation , DEAD-box RNA Helicases/genetics , Ear, Inner/abnormalities , Ear, Inner/cytology , Ear, Inner/innervation , Endoribonucleases/genetics , Epithelium/embryology , Epithelium/innervation , Fibroblast Growth Factor 10/metabolism , Hair Cells, Auditory/cytology , Mice , Mice, Knockout , Organogenesis , Ribonuclease III
16.
Evol Dev ; 10(1): 106-13, 2008.
Article in English | MEDLINE | ID: mdl-18184361

ABSTRACT

MicroRNAs (miRNAs) are an integral component of the metazoan genome and affect posttranscriptional repression of target messenger RNAs. The extreme phylogenetic conservation of certain miRNAs suggests their ancient origin and crucial function in conserved developmental processes. We demonstrate that highly conserved miRNA-183 orthologs exist in both deuterostomes and protostomes and their expression is predominant in ciliated ectodermal cells and organs. The miRNA-183 family members are expressed in vertebrate sensory hair cells, in innervated regions of invertebrate deuterostomes, and in sensilla of Drosophila and C. elegans. Thus, miRNA-183 family member expression is conserved in possibly homologous but morphologically distinct sensory cells and organs. The results suggest that miR-183 family members contribute specifically to neurosensory development or function, and that extant metazoan sensory organs are derived from cells that share genetic programs of common evolutionary origin.


Subject(s)
Evolution, Molecular , Invertebrates/genetics , MicroRNAs/metabolism , Sense Organs/metabolism , Vertebrates/genetics , Animals , Cilia/genetics , Cilia/metabolism , Conserved Sequence , Epithelial Cells/metabolism , Humans , In Situ Hybridization , Invertebrates/metabolism , MicroRNAs/chemistry , Phylogeny , Sense Organs/cytology , Sequence Alignment , Synteny , Vertebrates/metabolism
17.
Brain Res ; 1111(1): 95-104, 2006 Sep 21.
Article in English | MEDLINE | ID: mdl-16904081

ABSTRACT

MicroRNAs (miRNAs) are small non-coding RNAs that function through the RNA interference (RNAi) pathway and post-transcriptionally regulate gene expression in eukaryotic organisms. While miRNAs are known to affect cellular proliferation, differentiation, and morphological development, neither their expression nor roles in mammalian inner ear development have been characterized. We have investigated the extent of miRNA expression at various time points throughout maturation of the postnatal mouse inner ear by microarray analysis. Approximately one third of known miRNAs are detected in the inner ear, and their expression persists to adulthood. Expression of such miRNAs is validated by quantitative PCR and northern blot analysis. Further analysis by in situ hybridization demonstrates that certain miRNAs exhibit cell-specific expression patterns in the mouse inner ear. Notably, we demonstrate that miRNAs previously associated with mechanosensory cells in zebrafish are also expressed in hair cells of the auditory and vestibular endorgans. Our results demonstrate that miRNA expression is abundant in the mammalian inner ear and that certain miRNAs are evolutionarily associated with mechanosensory cell development and/or function. The data suggest that miRNAs contribute substantially to genetic programs intrinsic to development and function of the mammalian inner ear and that specific miRNAs might influence formation of sensory epithelia from the primitive otic neuroepithelium.


Subject(s)
Ear, Inner/growth & development , Ear, Inner/metabolism , Gene Expression Regulation, Developmental/genetics , Hair Cells, Auditory/growth & development , Hair Cells, Auditory/metabolism , MicroRNAs/genetics , Animals , Cell Differentiation/genetics , Ear, Inner/cytology , Hair Cells, Auditory/cytology , Labyrinth Supporting Cells/cytology , Labyrinth Supporting Cells/metabolism , Mice , MicroRNAs/analysis , MicroRNAs/metabolism , Nerve Tissue Proteins/biosynthesis , Nerve Tissue Proteins/genetics , Oligonucleotide Array Sequence Analysis , Organ of Corti/cytology , Organ of Corti/growth & development , Organ of Corti/metabolism , Vestibule, Labyrinth/cytology , Vestibule, Labyrinth/growth & development , Vestibule, Labyrinth/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...