DSpace Collection:https://hdl.handle.net/10316/1472024-03-29T10:25:08Z2024-03-29T10:25:08ZThe World of GPCR dimers - Mapping dopamine receptor D2 homodimers in different activation states and configuration arrangementsBueschbell, BeatrizMagalhães, Pedro R.Barreto, Carlos A. V.Melo, RitaSchiedel, Anke C.Machuqueiro, MiguelMoreira, Irina S.https://hdl.handle.net/10316/1144882024-03-28T11:58:27Z2023-01-01T00:00:00ZTitle: The World of GPCR dimers - Mapping dopamine receptor D2 homodimers in different activation states and configuration arrangements
Authors: Bueschbell, Beatriz; Magalhães, Pedro R.; Barreto, Carlos A. V.; Melo, Rita; Schiedel, Anke C.; Machuqueiro, Miguel; Moreira, Irina S.
Abstract: G protein-coupled receptors (GPCRs) are known to dimerize, but the molecular and structural basis of GPCR dimers is not well understood. In this study, we developed a computational framework to generate models of symmetric and asymmetric GPCR dimers using different monomer activation states and identified their most likely interfaces with molecular details. We chose the dopamine receptor D2 (D2R) homodimer as a case study because of its biological relevance and the availability of structural information. Our results showed that transmembrane domains 4 and 5 (TM4 and TM5) are mostly found at the dimer interface of the D2R dimer and that these interfaces have a subset of key residues that are mostly nonpolar from TM4 and TM5, which was in line with experimental studies. In addition, TM2 and TM3 appear to be relevant for D2R dimers. In some cases, the inactive configuration is unaffected by the partnered protomer, whereas in others, the active protomer adopts the properties of an inactive receptor. Additionally, the β-arrestin configuration displayed the properties of an active receptor in the absence of an agonist, suggesting that a switch to another meta-state during dimerization occurred. Our findings are consistent with the experimental data, and this method can be adapted to study heterodimers and potentially extended to include additional proteins such as G proteins or β-arrestins. In summary, this approach provides insight into the impact of the conformational status of partnered protomers on the overall quaternary GPCR macromolecular structure and dynamics.2023-01-01T00:00:00ZTranscriptome analysis reveals the high ribosomal inhibitory action of 1,4-naphthoquinone on Meloidogyne luci infective second-stage juvenilesCardoso, Joana M. S.Esteves, IvâniaEgas, ConceiçãoBraga, Mara E. M.Sousa, Herminio C. deAbrantes, IsabelMaleita, Carlahttps://hdl.handle.net/10316/1144782024-03-28T10:04:56Z2023-01-01T00:00:00ZTitle: Transcriptome analysis reveals the high ribosomal inhibitory action of 1,4-naphthoquinone on Meloidogyne luci infective second-stage juveniles
Authors: Cardoso, Joana M. S.; Esteves, Ivânia; Egas, Conceição; Braga, Mara E. M.; Sousa, Herminio C. de; Abrantes, Isabel; Maleita, Carla
Abstract: The root-knot nematode (RKN) Meloidogyne luci presents a threat to the production of several important crops. This nematode species was added to the European Plant Protection Organization Alert list in 2017. The scarce availability of efficient nematicides to control RKN and the phasing out of nematicides from the market have intensified the search for alternatives, such as phytochemicals with bionematicidal properties. The nematicidal activity of 1,4-naphthoquinone (1,4-NTQ) against M. luci has been demonstrated; however, knowledge of the potential mode(s) of action of this compound is still scarce. In this study, the transcriptome profile of M. luci second-stage juveniles (J2), the infective stage, in response to 1,4-NTQ exposure was determined by RNA-seq to identify genes and pathways that might be involved in 1,4-NTQ's mode(s) of action. Control treatments, consisting of nematodes exposed to Tween® 80 (1,4-NTQ solvent) and to water, were included in the analysis. A large set of differentially expressed genes (DEGs) was found among the three tested conditions, and a high number of downregulated genes were found between 1,4-NTQ treatment and water control, reflecting the inhibitory effect of this compound on M. luci, with a great impact on processes related to translation (ribosome pathway). Several other nematode gene networks and metabolic pathways affected by 1,4-NTQ were also identified, clarifying the possible mode of action of this promising bionematicide.2023-01-01T00:00:00ZExtracellular vesicles improve GABAergic transmission in Huntington's disease iPSC-derived neuronsBeatriz, MargaridaRodrigues, Ricardo J.Vilaça, RitaEgas, ConceiçãoPinheiro, Paulo S.Daley, George Q.Schlaeger, Thorsten M.Raimundo, NunoRego, A. CristinaLopes, Carlahttps://hdl.handle.net/10316/1144182024-03-27T11:20:49Z2023-01-01T00:00:00ZTitle: Extracellular vesicles improve GABAergic transmission in Huntington's disease iPSC-derived neurons
Authors: Beatriz, Margarida; Rodrigues, Ricardo J.; Vilaça, Rita; Egas, Conceição; Pinheiro, Paulo S.; Daley, George Q.; Schlaeger, Thorsten M.; Raimundo, Nuno; Rego, A. Cristina; Lopes, Carla
Abstract: Background: Extracellular vesicles (EVs) carry bioactive molecules associated with various biological
processes, including miRNAs. In both Huntington’s disease (HD) models and human samples, altered
expression of miRNAs involved in synapse regulation was reported. Recently, the use of EV cargo to
reverse phenotypic alterations in disease models with synaptopathy as the end result of the
pathophysiological cascade has become an interesting possibility.
Methods: Here, we assessed the contribution of EVs to GABAergic synaptic alterations using a human
HD model and studied the miRNA content of isolated EVs.
Results: After differentiating human induced pluripotent stem cells into electrophysiologically active
striatal-like GABAergic neurons, we found that HD-derived neurons displayed reduced density of
inhibitory synapse markers and GABA receptor-mediated ionotropic signaling. Treatment with EVs
secreted by control (CTR) fibroblasts reversed the deficits in GABAergic synaptic transmission and
increased the density of inhibitory synapses in HD-derived neuron cultures, while EVs from HD-derived
fibroblasts had the opposite effects on CTR-derived neurons. Moreover, analysis of miRNAs from
purified EVs identified a set of differentially expressed miRNAs between manifest HD, premanifest, and
CTR lines with predicted synaptic targets.
Conclusion: The EV-mediated reversal of the abnormal GABAergic phenotype in HD-derived neurons
reinforces the potential role of EV-miRNAs on synapse regulation.2023-01-01T00:00:00ZRoot-knot nematode assessment: species identification, distribution, and new host records in PortugalRusinque, LeidyCamacho, Maria JoãoSerra, ClaraNóbrega, FilomenaInácio, Maria L.https://hdl.handle.net/10316/1144142024-03-27T10:23:48Z2023-01-01T00:00:00ZTitle: Root-knot nematode assessment: species identification, distribution, and new host records in Portugal
Authors: Rusinque, Leidy; Camacho, Maria João; Serra, Clara; Nóbrega, Filomena; Inácio, Maria L.
Abstract: Considered one of the most devastating plant parasitic nematodes worldwide, Meloidogyne spp. (commonly known as the root-knot nematodes (RKNs)) are obligate sedentary endoparasites that establish in the roots, causing hyperplasia and hypertrophy of surrounding cells, triggering the formation of galls. These galls will affect root development and physiology, leading to substantial yield losses. During 2017-2022, an extensive survey of Meloidogyne species was undertaken in Portugal (mainland and islands). A total of 1,071 samples were collected by the National Plant Protection Organization (DGAV) and private farmers from different regions of the country and were analysed at the Laboratory of Nematology (NemaINIAV). Samples in which the presence of Meloidogyne sp. was detected were used to perform bioassays to obtain females and juveniles for further studies. Since the accurate identification of RKNs is an important aspect of crop management, morphological and biochemical characterisation was performed. The most common morphological features were observed, showing consistency with previous descriptions of the genus. The biochemical identification using the esterase (EST) phenotype revealed the phenotypes of Meloidogyne arenaria, M enterolobi, M. hispanica, M. hapla, M. incognita, M javanica, and M. luci. Meloidogyne incognita and M. javanica were found to be the most prevalent species in the different regions followed by M. arenaria and M. hapla. This is the first distribution report performed in Portugal on RKNs, contributing to the development of management strategies and to updated information on the status of these pests in Europe.2023-01-01T00:00:00Z