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1.
JAMA Neurol ; 80(6): 578-587, 2023 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-37126322

RESUMEN

Importance: Mesial temporal lobe epilepsy (MTLE) is the most common focal epilepsy subtype and is often refractory to antiseizure medications. While most patients with MTLE do not have pathogenic germline genetic variants, the contribution of postzygotic (ie, somatic) variants in the brain is unknown. Objective: To test the association between pathogenic somatic variants in the hippocampus and MTLE. Design, Setting, and Participants: This case-control genetic association study analyzed the DNA derived from hippocampal tissue of neurosurgically treated patients with MTLE and age-matched and sex-matched neurotypical controls. Participants treated at level 4 epilepsy centers were enrolled from 1988 through 2019, and clinical data were collected retrospectively. Whole-exome and gene-panel sequencing (each genomic region sequenced more than 500 times on average) were used to identify candidate pathogenic somatic variants. A subset of novel variants was functionally evaluated using cellular and molecular assays. Patients with nonlesional and lesional (mesial temporal sclerosis, focal cortical dysplasia, and low-grade epilepsy-associated tumors) drug-resistant MTLE who underwent anterior medial temporal lobectomy were eligible. All patients with available frozen tissue and appropriate consents were included. Control brain tissue was obtained from neurotypical donors at brain banks. Data were analyzed from June 2020 to August 2022. Exposures: Drug-resistant MTLE. Main Outcomes and Measures: Presence and abundance of pathogenic somatic variants in the hippocampus vs the unaffected temporal neocortex. Results: Of 105 included patients with MTLE, 53 (50.5%) were female, and the median (IQR) age was 32 (26-44) years; of 30 neurotypical controls, 11 (36.7%) were female, and the median (IQR) age was 37 (18-53) years. Eleven pathogenic somatic variants enriched in the hippocampus relative to the unaffected temporal neocortex (median [IQR] variant allele frequency, 1.92 [1.5-2.7] vs 0.3 [0-0.9]; P = .01) were detected in patients with MTLE but not in controls. Ten of these variants were in PTPN11, SOS1, KRAS, BRAF, and NF1, all predicted to constitutively activate Ras/Raf/mitogen-activated protein kinase (MAPK) signaling. Immunohistochemical studies of variant-positive hippocampal tissue demonstrated increased Erk1/2 phosphorylation, indicative of Ras/Raf/MAPK activation, predominantly in glial cells. Molecular assays showed abnormal liquid-liquid phase separation for the PTPN11 variants as a possible dominant gain-of-function mechanism. Conclusions and Relevance: Hippocampal somatic variants, particularly those activating Ras/Raf/MAPK signaling, may contribute to the pathogenesis of sporadic, drug-resistant MTLE. These findings may provide a novel genetic mechanism and highlight new therapeutic targets for this common indication for epilepsy surgery.


Asunto(s)
Epilepsia Refractaria , Epilepsia del Lóbulo Temporal , Epilepsia , Neocórtex , Humanos , Femenino , Adulto , Persona de Mediana Edad , Masculino , Epilepsia del Lóbulo Temporal/cirugía , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Estudios Retrospectivos , Hipocampo/patología , Epilepsia/patología
2.
Nat Chem Biol ; 18(12): 1341-1350, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36229685

RESUMEN

Patients with castration-resistant prostate cancer inevitably acquire resistance to antiandrogen therapies in part because of androgen receptor (AR) mutations or splice variants enabling restored AR signaling. Here we show that ligand-activated AR can form transcriptionally active condensates. Both structured and unstructured regions of AR contribute to the effective phase separation of AR and disordered N-terminal domain plays a predominant role. AR liquid-liquid phase separation behaviors faithfully report transcriptional activity and antiandrogen efficacy. Antiandrogens can promote phase separation and transcriptional activity of AR-resistant mutants in a ligand-independent manner. We conducted a phase-separation-based phenotypic screen and identified ET516 that specifically disrupts AR condensates, effectively suppresses AR transcriptional activity and inhibits the proliferation and tumor growth of prostate cancer cells expressing AR-resistant mutants. Our results demonstrate liquid-liquid phase separation as an emerging mechanism underlying drug resistance and show that targeting phase separation may provide a feasible approach for drug discovery.


Asunto(s)
Neoplasias de la Próstata Resistentes a la Castración , Neoplasias de la Próstata , Masculino , Humanos , Receptores Androgénicos/genética , Antagonistas de Andrógenos/farmacología , Antagonistas de Andrógenos/uso terapéutico , Ligandos , Resistencia a Antineoplásicos , Neoplasias de la Próstata/tratamiento farmacológico , Línea Celular Tumoral , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/genética , Neoplasias de la Próstata Resistentes a la Castración/patología
3.
Biochem Biophys Res Commun ; 600: 150-155, 2022 04 16.
Artículo en Inglés | MEDLINE | ID: mdl-35219918

RESUMEN

SHP1 is a non-receptor protein tyrosine phosphatase that is widely expressed in hematopoietic cells such as white blood cells, neutrophils, and immune cells. SHP1 can regulate the occurrence and differentiation of immune cells and plays an important role as a tumor suppressor. Previous studies have suggested that SHP2, the homologous protein of phosphatase SHP1, can undergo liquid-liquid phase separation (LLPS). Therefore, in this study, we investigated if SHP1 is also capable of LLPS. To the best of our knowledge, our study is the first to reveal that SHP1 has the ability to undergo LLPS. In addition, we identified an important residue, SHP1-R360E, that can completely inhibit the LLPS ability of SHP1, but this mutation has no remarkable effect on SHP1's enzymatic activity. This allows us to explore the phosphatase activity and phase separation ability of SHP1 separately, providing a basis for future exploration of the phase separation mechanism of phosphatases.


Asunto(s)
Proteína Tirosina Fosfatasa no Receptora Tipo 11 , Diferenciación Celular , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genética , Proteína Tirosina Fosfatasa no Receptora Tipo 11/metabolismo , Proteína Tirosina Fosfatasa no Receptora Tipo 6/genética , Proteína Tirosina Fosfatasa no Receptora Tipo 6/metabolismo
4.
Cell ; 183(2): 490-502.e18, 2020 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-33002410

RESUMEN

The non-receptor protein tyrosine phosphatase (PTP) SHP2, encoded by PTPN11, plays an essential role in RAS-mitogen-activated protein kinase (MAPK) signaling during normal development. It has been perplexing as to why both enzymatically activating and inactivating mutations in PTPN11 result in human developmental disorders with overlapping clinical manifestations. Here, we uncover a common liquid-liquid phase separation (LLPS) behavior shared by these disease-associated SHP2 mutants. SHP2 LLPS is mediated by the conserved well-folded PTP domain through multivalent electrostatic interactions and regulated by an intrinsic autoinhibitory mechanism through conformational changes. SHP2 allosteric inhibitors can attenuate LLPS of SHP2 mutants, which boosts SHP2 PTP activity. Moreover, disease-associated SHP2 mutants can recruit and activate wild-type (WT) SHP2 in LLPS to promote MAPK activation. These results not only suggest that LLPS serves as a gain-of-function mechanism involved in the pathogenesis of SHP2-associated human diseases but also provide evidence that PTP may be regulated by LLPS that can be therapeutically targeted.


Asunto(s)
Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteína Tirosina Fosfatasa no Receptora Tipo 11/metabolismo , Células A549 , Animales , Niño , Preescolar , Femenino , Mutación con Ganancia de Función/genética , Células HEK293 , Células Endoteliales de la Vena Umbilical Humana , Humanos , Sistema de Señalización de MAP Quinasas/fisiología , Masculino , Ratones , Células Madre Embrionarias de Ratones , Mutación/genética , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genética , Transducción de Señal , Dominios Homologos src/genética
5.
ChemMedChem ; 13(17): 1763-1770, 2018 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-30084216

RESUMEN

The Bcl-2 family proteins are key regulators of the intrinsic apoptotic pathway and are among the validated targets for developing anticancer drugs. Protein-protein interactions between the pro- and antiapoptotic members of this family determine mitochondrial outer-membrane permeabilization. Elucidating such protein-protein interactions in a quantitative way is helpful for network pharmacology studies on the Bcl-2 family, which, in turn, will provide valuable guidance for developing new anticancer therapies. In this study, the binding affinities of the BH3 peptides derived from eight proapoptotic BH3-only proteins (i.e., Bid, Bim, Puma, Noxa, Bad, Bmf, Bik, Hrk) against five well-studied antiapoptotic proteins (i.e., Bcl-xL , Bcl-2, Mcl-1, Bcl-w, Bfl-1) in the Bcl-2 family have been measured. Three different types of binding assay (i.e., surface plasmon resonance, fluorescence polarization, and homogeneous time-resolved fluorescence) were employed for cross-validation. The results confirmed that each proapoptotic BH3 peptide exhibited a distinct binding profile against the five antiapoptotic proteins. The binding data obtained herein serve as a fresh update or correction to existing knowledge. It is expected that such binding data will be helpful for building more accurate mathematical network models for depicting the complex protein-protein interactions within the Bcl-2 family.


Asunto(s)
Fragmentos de Péptidos/farmacología , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/farmacología , Sitios de Unión/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Estructura Molecular , Fragmentos de Péptidos/síntesis química , Fragmentos de Péptidos/química , Proteínas Proto-Oncogénicas/síntesis química , Proteínas Proto-Oncogénicas/química , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Relación Estructura-Actividad
6.
Front Microbiol ; 9: 198, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29527193

RESUMEN

Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans, and that EFG1-Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC), the fungal burden and the levels of pro-inflammatory cytokines, IL-1ß, IL-6 and TNF-α showed a increase on co-infection with S. agalactiae, while the level of TH17 T cells and IL-17 in the cervicovaginal lavage fluid were significantly decreased. Our results indicate that S. agalactiae inhibits C. albicans hyphal development by downregulating the expression of EFG1-Hwp1. The interaction between S. agalactiae and C. albicans may attenuate host vaginal mucosal TH17 immunity and contribute to mucosal colonization by C. albicans.

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