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The 13 Hsp70 proteins in humans act on unique sets of substrates with diversity often being attributed to J-domain-containing protein (Hsp40 or JDP) cofactors. We were therefore surprised to find drastically different binding affinities for Hsp70-peptide substrates, leading us to probe substrate specificity among the 8 canonical Hsp70s from humans. We used peptide arrays to characterize Hsp70 binding and then mined these data using machine learning to develop an algorithm for isoform-specific prediction of Hsp70 binding sequences. The results of this algorithm revealed recognition patterns not predicted based on local sequence alignments. We then showed that none of the human isoforms can complement heat-shocked DnaK knockout Escherichia coli cells. However, chimeric Hsp70s consisting of the human nucleotide-binding domain and the substrate-binding domain of DnaK complement during heat shock, providing further evidence in vivo of the divergent function of the Hsp70 substrate-binding domains. We also demonstrated that the differences in heat shock complementation among the chimeras are not due to loss of DnaJ binding. Although we do not exclude JDPs as additional specificity factors, our data demonstrate substrate specificity among the Hsp70s, which has important implications for inhibitor development in cancer and neurodegeneration.
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Proteínas de Escherichia coli , Proteínas de Choque Térmico , Humanos , Proteínas de Choque Térmico/metabolismo , Proteínas de Escherichia coli/química , Sitios de Unión , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas del Choque Térmico HSP40/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Péptidos/metabolismo , Unión ProteicaRESUMEN
Transmembrane Cav2.2 (N-type) voltage-gated calcium channels are genetically and pharmacologically validated, clinically relevant pain targets. Clinical block of Cav2.2 (e.g., with Prialt/Ziconotide) or indirect modulation [e.g., with gabapentinoids such as Gabapentin (GBP)] mitigates chronic pain but is encumbered by side effects and abuse liability. The cytosolic auxiliary subunit collapsin response mediator protein 2 (CRMP2) targets Cav2.2 to the sensory neuron membrane and regulates their function via an intrinsically disordered motif. A CRMP2-derived peptide (CBD3) uncouples the Cav2.2-CRMP2 interaction to inhibit calcium influx, transmitter release, and pain. We developed and applied a molecular dynamics approach to identify the A1R2 dipeptide in CBD3 as the anchoring Cav2.2 motif and designed pharmacophore models to screen 27 million compounds on the open-access server ZincPharmer. Of 200 curated hits, 77 compounds were assessed using depolarization-evoked calcium influx in rat dorsal root ganglion neurons. Nine small molecules were tested electrophysiologically, while one (CBD3063) was also evaluated biochemically and behaviorally. CBD3063 uncoupled Cav2.2 from CRMP2, reduced membrane Cav2.2 expression and Ca2+ currents, decreased neurotransmission, reduced fiber photometry-based calcium responses in response to mechanical stimulation, and reversed neuropathic and inflammatory pain across sexes in two different species without changes in sensory, sedative, depressive, and cognitive behaviors. CBD3063 is a selective, first-in-class, CRMP2-based peptidomimetic small molecule, which allosterically regulates Cav2.2 to achieve analgesia and pain relief without negative side effect profiles. In summary, CBD3063 could potentially be a more effective alternative to GBP for pain relief.
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Dolor Crónico , Peptidomiméticos , Ratas , Animales , Dolor Crónico/tratamiento farmacológico , Dolor Crónico/metabolismo , Ratas Sprague-Dawley , Peptidomiméticos/farmacología , Calcio/metabolismo , Canales de Calcio Tipo N/genética , Canales de Calcio Tipo N/metabolismo , Células Receptoras Sensoriales/metabolismo , Ganglios Espinales/metabolismoRESUMEN
Small molecules directly targeting the voltage-gated sodium channel (VGSC) NaV1.7 have not been clinically successful. We reported that preventing the addition of a small ubiquitin-like modifier onto the NaV1.7-interacting cytosolic collapsin response mediator protein 2 (CRMP2) blocked NaV1.7 function and was antinociceptive in rodent models of neuropathic pain. Here, we discovered a CRMP2 regulatory sequence (CRS) unique to NaV1.7 that is essential for this regulatory coupling. CRMP2 preferentially bound to the NaV1.7 CRS over other NaV isoforms. Substitution of the NaV1.7 CRS with the homologous domains from the other eight VGSC isoforms decreased NaV1.7 currents. A cell-penetrant decoy peptide corresponding to the NaV1.7-CRS reduced NaV1.7 currents and trafficking, decreased presynaptic NaV1.7 expression, reduced spinal CGRP release, and reversed nerve injury-induced mechanical allodynia. Importantly, the NaV1.7-CRS peptide did not produce motor impairment, nor did it alter physiological pain sensation, which is essential for survival. As a proof-of-concept for a NaV1.7 -targeted gene therapy, we packaged a plasmid encoding the NaV1.7-CRS in an AAV virus. Treatment with this virus reduced NaV1.7 function in both rodent and rhesus macaque sensory neurons. This gene therapy reversed and prevented mechanical allodynia in a model of nerve injury and reversed mechanical and cold allodynia in a model of chemotherapy-induced peripheral neuropathy. These findings support the conclusion that the CRS domain is a targetable region for the treatment of chronic neuropathic pain.
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Dolor Crónico , Neuralgia , Animales , Hiperalgesia/inducido químicamente , Dolor Crónico/genética , Dolor Crónico/terapia , Macaca mulatta/metabolismo , Neuralgia/genética , Neuralgia/terapia , Canal de Sodio Activado por Voltaje NAV1.7/genética , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Ganglios Espinales/metabolismo , Canal de Sodio Activado por Voltaje NAV1.8RESUMEN
Pontocerebellar Hypoplasia 1B (PCH1B) is a severe autosomal recessive neurological disorder that is associated with mutations in the exosome complex component RRP40 (EXOSC3) gene. We generated and characterized an iPSC line from an individual with PCH1B that harbors a recessive homozygous c.395 A > C mutation in EXOSC3 and a family matched control from the probands unaffected mother. Each iPSC line presents with normal morphology and karyotype and express high levels of pluripotent markers. UAZTi009-A and UAZTi011-A are capable of directed differentiation and can be used as a vital experimental tool to study the development of PCH1B.
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Complejo Multienzimático de Ribonucleasas del Exosoma , Proteínas de Unión al ARN , Humanos , Mutación/genética , Células Madre Pluripotentes Inducidas , Línea CelularRESUMEN
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with no cure or effective treatment in which TAR DNA Binding Protein of 43 kDa (TDP-43) abnormally accumulates into misfolded protein aggregates in affected neurons. It is widely accepted that protein misfolding and aggregation promotes proteotoxic stress. The molecular chaperones are a primary line of defense against proteotoxic stress, and there has been long-standing interest in understanding the relationship between chaperones and aggregated protein in ALS. Of particular interest are the heat shock protein of 70 kDa (Hsp70) family of chaperones. However, defining which of the 13 human Hsp70 isoforms is critical for ALS has presented many challenges. To gain insight into the specific Hsp70 that modulates TDP-43, we investigated the relationship between TDP-43 and the Hsp70s using proximity-dependent biotin identification (BioID) and discovered several Hsp70 isoforms associated with TDP-43 in the nucleus, raising the possibility of an interaction with native TDP-43. We further found that HspA5 bound specifically to the RNA-binding domain of TDP-43 using recombinantly expressed proteins. Moreover, in a Drosophila strain that mimics ALS upon TDP-43 expression, the mRNA levels of the HspA5 homologue (Hsc70.3) were significantly increased. Similarly we observed upregulation of HspA5 in prefrontal cortex neurons from human ALS patients. Finally, overexpression of HspA5 in Drosophila rescued TDP-43-induced toxicity, suggesting that upregulation of HspA5 may have a compensatory role in ALS pathobiology.
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Esclerosis Amiotrófica Lateral , Enfermedades Neurodegenerativas , Esclerosis Amiotrófica Lateral/metabolismo , Animales , Proteínas de Unión al ADN/metabolismo , Drosophila/metabolismo , Chaperón BiP del Retículo Endoplásmico , Proteínas HSP70 de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Chaperonas MolecularesRESUMEN
Neurodegenerative diseases represent a formidable challenge to global health. As advances in other areas of medicine grant healthy living into later decades of life, aging diseases such as Alzheimer's disease (AD) and other neurodegenerative disorders can diminish the quality of these additional years, owed largely to the lack of efficacious treatments and the absence of durable cures. Alzheimer's disease prevalence is predicted to more than double in the next 30 years, affecting nearly 15 million Americans, with AD-associated costs exceeding $1 billion by 2050. Delaying onset of AD and other neurodegenerative diseases is critical to improving the quality of life for patients and reducing the burden of disease on caregivers and healthcare systems. Significant progress has been made to model disease pathogenesis and identify points of therapeutic intervention. While some researchers have contributed to our understanding of the proteins and pathways that drive biological dysfunction in disease using in vitro and in vivo models, others have provided mathematical, biophysical, and computational technologies to identify potential therapeutic compounds using in silico modeling. The most exciting phase of the drug discovery process is now: by applying a target-directed approach that leverages the strengths of multiple techniques and validates lead hits using Drosophila as an animal model of disease, we are on the fast-track to identifying novel therapeutics to restore health to those impacted by neurodegenerative disease.
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Neurodegeneration is a progressive deterioration of neural structures leading to cognitive or motor impairment of the affected patient. There is still no effective therapy for any of the most common neurodegenerative diseases (NDs) such as Alzheimer's or Parkinson's disease. Although NDs exhibit distinct clinical characteristics, many are characterized by the accumulation of misfolded proteins or peptide fragments in the brain and/or spinal cord. The presence of similar inclusion bodies in patients with diverse NDs provides a rationale for developing therapies directed at overlapping disease mechanisms. A novel targeting strategy involves the use of aptamers for therapeutic development. Aptamers are short nucleic acid ligands able to recognize molecular targets with high specificity and high affinity. Despite the fact that several academic groups have shown that aptamers have the potential to be used in therapeutic and diagnostic applications, their clinical translation is still limited. In this study, we describe aptamers that have been developed against proteins relevant to NDs, including prion protein and amyloid beta (Aß), cell surface receptors and other cytoplasmic proteins. This review also describes advances in the application of these aptamers in imaging, protein detection, and protein quantification, and it provides insights about their accelerated clinical use for disease diagnosis and therapy.
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Aptámeros de Nucleótidos , Priones , Péptidos beta-Amiloides/genética , Aptámeros de Nucleótidos/química , Aptámeros de Nucleótidos/genética , Aptámeros de Nucleótidos/uso terapéutico , Humanos , Ligandos , Fragmentos de PéptidosRESUMEN
The voltage-gated sodium NaV1.7 channel, critical for sensing pain, has been actively targeted by drug developers; however, there are currently no effective and safe therapies targeting NaV1.7. Here, we tested whether a different approach, indirect NaV1.7 regulation, could have antinociceptive effects in preclinical models. We found that preventing addition of small ubiquitin-like modifier (SUMO) on the NaV1.7-interacting cytosolic collapsin response mediator protein 2 (CRMP2) blocked NaV1.7 functions and had antinociceptive effects in rodents. In silico targeting of the SUMOylation site in CRMP2 (Lys374) identified >200 hits, of which compound 194 exhibited selective in vitro and ex vivo NaV1.7 engagement. Orally administered 194 was not only antinociceptive in preclinical models of acute and chronic pain but also demonstrated synergy alongside other analgesicswithout eliciting addiction, rewarding properties, or neurotoxicity. Analgesia conferred by 194 was opioid receptor dependent. Our results demonstrate that 194 is a first-in-class protein-protein inhibitor that capitalizes on CRMP2-NaV1.7 regulation to deliver safe analgesia in rodents.
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Dolor Crónico , Canal de Sodio Activado por Voltaje NAV1.7 , Analgésicos/farmacología , Analgésicos/uso terapéutico , Animales , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Roedores/metabolismo , SumoilaciónRESUMEN
The pathogenicity of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been attributed to its ability to enter through the membrane-bound angiotensin-converting enzyme 2 (ACE2) receptor. Therefore, it has been heavily speculated that angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) therapy may modulate SARS-CoV-2 infection. In this study, exposure of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) and human endothelial cells (hECs) to SARS-CoV-2 identified significant differences in protein coding genes involved in immunity, viral response, and cardiomyocyte/endothelial structure. Specifically, transcriptome changes were identified in the tumor necrosis factor (TNF), interferon α/ß, and mitogen-activated protein kinase (MAPK) (hPSC-CMs) as well as nuclear factor kappa-B (NF-κB) (hECs) signaling pathways. However, pre-treatment of hPSC-CMs or hECs with two widely prescribed antihypertensive medications, losartan and lisinopril, did not affect the susceptibility of either cell type to SARS-CoV-2 infection. These findings demonstrate the toxic effects of SARS-CoV-2 in hPSC-CMs/hECs and, taken together with newly emerging multicenter trials, suggest that antihypertensive drug treatment alone does not alter SARS-CoV-2 infection.
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Antihipertensivos/farmacología , Tratamiento Farmacológico de COVID-19 , Células Endoteliales/efectos de los fármacos , Miocitos Cardíacos/efectos de los fármacos , COVID-19/genética , Células Cultivadas , Susceptibilidad a Enfermedades , Células Endoteliales/metabolismo , Interacciones Huésped-Patógeno/efectos de los fármacos , Humanos , Lisinopril/farmacología , Losartán/farmacología , Miocitos Cardíacos/metabolismo , SARS-CoV-2/efectos de los fármacos , SARS-CoV-2/fisiología , Transcriptoma/efectos de los fármacosRESUMEN
Tar DNA binding (TDP)-43 proteinopathy, typically described as cytoplasmic accumulation of highly modified and misfolded TDP-43 molecules, is characteristic of several neurodegenerative diseases such as Amyotrophic Lateral Sclerosis (ALS) and limbic-predominant age-related TDP-43 encephalopathy (LATE). TDP-43 proposed proteinopathies include homeostatic imbalance between nuclear and cytoplasmic localization, aggregation of ubiquitinated and hyper-phosphorylated TDP-43, and an increase in protein truncation of cytoplasmic TDP-43. Given the therapeutic interest of targeting TDP-43, this review focuses on the current landscape of strategies, ranging from biologics to small molecules, that directly target TDP-43. Antibodies, peptides and compounds have been designed or found to recognize specific TDP-43 sequences but alleviate TDP-43 toxicity through different mechanisms. While two antibodies described here were able to induce degradation of pathological TDP-43, the peptides and small molecules were primarily designed to reduce aggregation of TDP-43. Furthermore, we discuss promising emerging therapeutic targets.
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RNA targeting has gained traction over the past decade. It has become clear that dysregulation of RNA can be linked to many diseases, leading to a need for new scaffolds recognizing RNA specifically. Long noncoding RNAs are emerging as key controllers of gene expression and potential therapeutic targets. However, traditional targeting methods have overwhelmingly been focused on proteins. In this study, we used a protein computational tool and found several possible targetable pockets in a structurally characterized long noncoding RNA, MALAT1. Screening against those identified pockets revealed several hit compounds. We tested the binding of those compounds to MALAT1 RNA and tRNA as a negative control, using SPR. While several compounds were nonspecific binders, others were able to recognize MALAT1 specifically. One of them, MTC07, has an apparent affinity of 400.2 ± 14.4 µM. Although it has weak affinity, MTC07 is the first compound targeting MALAT1 originating from in silico docking.
RESUMEN
In this study, we targeted the N-terminal domain (NTD) of transactive response (TAR) DNA binding protein (TDP-43), which is implicated in several neurodegenerative diseases. In silico docking of 50K compounds to the NTD domain of TDP-43 identified a small molecule (nTRD22) that is bound to the N-terminal domain. Interestingly, nTRD22 caused allosteric modulation of the RNA binding domain (RRM) of TDP-43, resulting in decreased binding to RNA in vitro. Moreover, incubation of primary motor neurons with nTRD22 induced a reduction of TDP-43 protein levels, similar to TDP-43 RNA binding-deficient mutants and supporting a disruption of TDP-43 binding to RNA. Finally, nTRD22 mitigated motor impairment in a Drosophila model of amyotrophic lateral sclerosis. Our findings provide an exciting way of allosteric modulation of the RNA-binding region of TDP-43 through the N-terminal domain.
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Regulación Alostérica/efectos de los fármacos , Proteínas de Unión al ADN/metabolismo , Dominios Proteicos/efectos de los fármacos , ARN/metabolismo , Bibliotecas de Moléculas Pequeñas/farmacología , Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Esclerosis Amiotrófica Lateral/metabolismo , Esclerosis Amiotrófica Lateral/fisiopatología , Animales , Sitios de Unión/efectos de los fármacos , Proteínas de Unión al ADN/química , Modelos Animales de Enfermedad , Drosophila , Humanos , Simulación del Acoplamiento Molecular , Bibliotecas de Moléculas Pequeñas/químicaRESUMEN
[This corrects the article DOI: 10.3389/fnmol.2019.00301.].
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Anti-apoptotic Bcl-2 family proteins are overexpressed in a wide spectrum of cancers and have become well validated therapeutic targets. Cancer cells display survival dependence on individual or subsets of anti-apoptotic proteins that could be effectively targeted by multimodal inhibitors. We designed a 2,5-substituted benzoic acid scaffold that displayed equipotent binding to Mcl-1 and Bfl-1. Structure-based design was guided by several solved cocrystal structures with Mcl-1, leading to the development of compound 24, which binds both Mcl-1 and Bfl-1 with Ki values of 100 nM and shows appreciable selectivity over Bcl-2/Bcl-xL. The selective binding profile of 24 was translated to on-target cellular activity in model lymphoma cell lines. These studies lay a foundation for developing more advanced dual Mcl-1/Bfl-1 inhibitors that have potential to provide greater single agent efficacy and broader coverage to combat resistance in several types of cancer than selective Mcl-1 inhibitors alone.
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Antineoplásicos/farmacología , Ácido Benzoico/farmacología , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Animales , Antineoplásicos/química , Apoptosis/efectos de los fármacos , Ácido Benzoico/química , Línea Celular Tumoral , Humanos , Linfoma/tratamiento farmacológico , Linfoma/metabolismo , Ratones , Ratones Transgénicos , Antígenos de Histocompatibilidad Menor/metabolismo , Simulación del Acoplamiento Molecular , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismoRESUMEN
Naringenin (2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-4-one is a natural flavonoid found in fruits from the citrus family. Because (2S)-naringenin is known to racemize, its bioactivity might be related to one or both enantiomers. Computational studies predicted that (2R)-naringenin may act on voltage-gated ion channels, particularly the N-type calcium channel (CaV2.2) and the NaV1.7 sodium channel-both of which are key for pain signaling. Here we set out to identify the possible mechanism of action of naringenin. Naringenin inhibited depolarization-evoked Ca2+ influx in acetylcholine-, ATP-, and capsaicin-responding rat dorsal root ganglion (DRG) neurons. This was corroborated in electrophysiological recordings from DRG neurons. Pharmacological dissection of each of the voltage-gated Ca2+ channels subtypes could not pinpoint any selectivity of naringenin. Instead, naringenin inhibited NaV1.8-dependent and tetrodotoxin (TTX)-resistant while sparing tetrodotoxin sensitive (TTX-S) voltage-gated Na+ channels as evidenced by the lack of further inhibition by the NaV1.8 blocker A-803467. The effects of the natural flavonoid were validated ex vivo in spinal cord slices where naringenin decreased both the frequency and amplitude of sEPSC recorded in neurons within the substantia gelatinosa. The antinociceptive potential of naringenin was evaluated in male and female mice. Naringenin had no effect on the nociceptive thresholds evoked by heat. Naringenin's reversed allodynia was in mouse models of postsurgical and neuropathic pain. Here, driven by a call by the National Center for Complementary and Integrative Health's strategic plan to advance fundamental research into basic biological mechanisms of the action of natural products, we advance the antinociceptive potential of the flavonoid naringenin.
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Analgésicos/farmacología , Flavanonas/farmacología , Ganglios Espinales/citología , Canal de Sodio Activado por Voltaje NAV1.8/efectos de los fármacos , Nocicepción/efectos de los fármacos , Células Receptoras Sensoriales/efectos de los fármacos , Bloqueadores de los Canales de Sodio/farmacología , Sodio/metabolismo , Analgésicos/química , Analgésicos/uso terapéutico , Animales , Canales de Calcio/efectos de los fármacos , Señalización del Calcio/efectos de los fármacos , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Femenino , Flavanonas/química , Flavanonas/metabolismo , Flavanonas/uso terapéutico , Hiperalgesia/tratamiento farmacológico , Péptidos y Proteínas de Señalización Intercelular/química , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Masculino , Ratones , Modelos Moleculares , Proteínas del Tejido Nervioso/química , Proteínas del Tejido Nervioso/metabolismo , Neuralgia/tratamiento farmacológico , Dolor Postoperatorio/tratamiento farmacológico , Conformación Proteica , Mapeo de Interacción de Proteínas , Ratas , Ratas Sprague-Dawley , Células Receptoras Sensoriales/clasificación , Células Receptoras Sensoriales/metabolismo , Bloqueadores de los Canales de Sodio/química , Bloqueadores de los Canales de Sodio/uso terapéutico , Organismos Libres de Patógenos Específicos , Relación Estructura-ActividadRESUMEN
We have previously reported that the microtubule-associated collapsin response mediator protein 2 (CRMP2) is necessary for the expression of chronic pain. CRMP2 achieves this control of nociceptive signaling by virtue of its ability to regulate voltage-gated calcium and sodium channels. To date, however, no drugs exist that target CRMP2. Recently, the small molecule edonerpic maleate (1 -{3-[2-(1-benzothiophen-5-yl)ethoxy]propyl}azetidin-3-ol maleate), a candidate therapeutic for Alzheimer's disease was reported to be a novel CRMP2 binding compound with the potential to decrease its phosphorylation level in cortical tissues in vivo. Here we sought to determine the mechanism of action of edonerpic maleate and test its possible effect in a rodent model of chronic pain. We observed: (i) no binding between human CRMP2 and edonerpic maleate; (ii) edonerpic maleate had no effect on CRMP2 expression and phosphorylation in dorsal root ganglion (DRG) neurons; (iii) edonerpic maleate-decreased calcium but increased sodium current density in DRG neurons; and (iv) edonerpic maleate was ineffective in reversing post-surgical allodynia in male and female mice. Thus, while CRMP2 inhibiting compounds remain a viable strategy for developing new mechanism-based pain inhibitors, edonerpic maleate is an unlikely candidate.
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Hiperalgesia/tratamiento farmacológico , Maleatos/administración & dosificación , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Tiofenos/administración & dosificación , Animales , Calcio/metabolismo , Evaluación Preclínica de Medicamentos , Femenino , Ganglios Espinales/metabolismo , Humanos , Hiperalgesia/genética , Hiperalgesia/metabolismo , Péptidos y Proteínas de Señalización Intercelular/genética , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Masculino , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , FosforilaciónRESUMEN
RNA dysregulation likely contributes to disease pathogenesis of amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. A pathological form of the transactive response (TAR) DNA binding protein (TDP-43) binds to RNA in stress granules and forms membraneless, amyloid-like TDP-43 aggregates in the cytoplasm of ALS motor neurons. In this study, we hypothesized that by targeting the RNA recognition motif (RRM) domains of TDP-43 that confer a pathogenic interaction between TDP-43 and RNA, motor neuron toxicity could be reduced. In silico docking of 50000 compounds to the RRM domains of TDP-43 identified a small molecule (rTRD01) that (i) bound to TDP-43's RRM1 and RRM2 domains, (ii) partially disrupted TDP-43's interaction with the hexanucleotide RNA repeat of the disease-linked c9orf72 gene, but not with (UG)6 canonical binding sequence of TDP-43, and (iii) improved larval turning, an assay measuring neuromuscular coordination and strength, in an ALS fly model based on the overexpression of mutant TDP-43. Our findings provide an instructive example of a chemical biology approach pivoted to discover small molecules targeting RNA-protein interactions in neurodegenerative diseases.
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Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Fármacos Neuroprotectores/uso terapéutico , Piperidinas/uso terapéutico , Unión Proteica/efectos de los fármacos , Pirazinas/uso terapéutico , Animales , Secuencia de Bases , Sitios de Unión , Proteínas de Unión al ADN/química , Proteínas de Drosophila/química , Drosophila melanogaster/química , Drosophila melanogaster/efectos de los fármacos , Locomoción/efectos de los fármacos , Simulación del Acoplamiento Molecular , Fármacos Neuroprotectores/metabolismo , Piperidinas/metabolismo , Dominios Proteicos/efectos de los fármacos , Pirazinas/metabolismo , ARN/metabolismo , Bibliotecas de Moléculas Pequeñas/metabolismoRESUMEN
Inhibition of voltage-gated calcium (CaV) channels is a potential therapy for many neurological diseases including chronic pain. Neuronal CaV1/CaV2 channels are composed of α, ß, γ and α2δ subunits. The ß subunits of CaV channels are cytoplasmic proteins that increase the surface expression of the pore-forming α subunit of CaV. We targeted the high-affinity protein-protein interface of CaVß's pocket within the CaVα subunit. Structure-based virtual screening of 50,000 small molecule library docked to the ß subunit led to the identification of 2-(3,5-dimethylisoxazol-4-yl)-N-((4-((3-phenylpropyl)amino)quinazolin-2-yl)methyl)acetamide (IPPQ). This small molecule bound to CaVß and inhibited its coupling with N-type voltage-gated calcium (CaV2.2) channels, leading to a reduction in CaV2.2 currents in rat dorsal root ganglion sensory neurons, decreased presynaptic localization of CaV2.2 in vivo, decreased frequency of spontaneous excitatory postsynaptic potentials and miniature excitatory postsynaptic potentials, and inhibited release of the nociceptive neurotransmitter calcitonin gene-related peptide from spinal cord. IPPQ did not target opioid receptors nor did it engage inhibitory G protein-coupled receptor signaling. IPPQ was antinociceptive in naive animals and reversed allodynia and hyperalgesia in models of acute (postsurgical) and neuropathic (spinal nerve ligation, chemotherapy- and gp120-induced peripheral neuropathy, and genome-edited neuropathy) pain. IPPQ did not cause akinesia or motor impairment, a common adverse effect of CaV2.2 targeting drugs, when injected into the brain. IPPQ, a quinazoline analog, represents a novel class of CaV2.2-targeting compounds that may serve as probes to interrogate CaVα-CaVß function and ultimately be developed as a nonopioid therapeutic for chronic pain.
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Analgésicos/uso terapéutico , Bloqueadores de los Canales de Calcio/uso terapéutico , Canales de Calcio Tipo N/efectos de los fármacos , Canales de Calcio/efectos de los fármacos , Quinazolinas/uso terapéutico , Animales , Células CHO , Péptido Relacionado con Gen de Calcitonina/metabolismo , Simulación por Computador , Cricetulus , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Ganglios Espinales/citología , Ganglios Espinales/efectos de los fármacos , Hiperalgesia/tratamiento farmacológico , Masculino , Neuralgia/tratamiento farmacológico , Cultivo Primario de Células , Ratas , Ratas Sprague-Dawley , Médula Espinal/efectos de los fármacos , Médula Espinal/metabolismoRESUMEN
TAR DNA-binding protein 43 (TDP-43) is a ubiquitously expressed nuclear protein that influences diverse cellular processes by regulating alternative splicing of RNA and microRNA biogenesis. It is also a pathological protein found in sporadic ALS and in the most common subtype of frontotemporal lobar degeneration with ubiquitinated inclusions (FLTD-U). TDP-43 has two tandem RNA-binding domains, RRM1 and RRM2. The NMR structure of TDP-43 was solved in the presence of UG-rich RNA sequences bound to the RRM1 and RRM2 domains. Here we report the backbone assignment of apo TDP-43. The chemical shift (HN, N, C, Cα and Cß) analysis shows the predicted regions of secondary structure are in good agreement with those observed for TDP-43 in complex with RNA. However, our data show that the apo structure of TPD-43 has increased flexibility in the regions that would normally have been used to anchor the RNA bases. The backbone chemical shifts assignments will prove useful in the study of TDP-43 interaction with non-canonical RNA and RRM-binding proteins.
Asunto(s)
Apoproteínas/química , Proteínas de Unión al ADN/química , Resonancia Magnética Nuclear Biomolecular , Motivo de Reconocimiento de ARN , Secuencia de Aminoácidos , Isótopos de Carbono , Humanos , Isótopos de Nitrógeno , Estructura Secundaria de Proteína , ProtonesRESUMEN
For an affliction that debilitates an estimated 50 million adults in the United States, the current chronic pain management approaches are inadequate. The Centers for Disease Control and Prevention have called for a minimization in opioid prescription and use for chronic pain conditions, and thus, it is imperative to discover alternative non-opioid based strategies. For the realization of this call, a library of natural products was screened in search of pharmacological inhibitors of both voltage-gated calcium channels and voltage-gated sodium channels, which are excellent targets due to their well-established roles in nociceptive pathways. We discovered (-)-hardwickiic acid ((-)-HDA) and hautriwaic acid (HTA) isolated from plants, Croton californicus and Eremocarpus setigerus, respectively, inhibited tetrodotoxin-sensitive sodium, but not calcium or potassium, channels in small diameter, presumptively nociceptive, dorsal root ganglion (DRG) neurons. Failure to inhibit spontaneous postsynaptic excitatory currents indicated a preferential targeting of voltage-gated sodium channels over voltage-gated calcium channels by these extracts. Neither compound was a ligand at opioid receptors. Finally, we identified the potential of both (-)-HDA and HTA to reverse chronic pain behavior in preclinical rat models of HIV-sensory neuropathy, and for (-)-HDA specifically, in chemotherapy-induced peripheral neuropathy. Our results illustrate the therapeutic potential for (-)-HDA and HTA for chronic pain management and could represent a scaffold, that, if optimized by structure-activity relationship studies, may yield novel specific sodium channel antagonists for pain relief.