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Background: T-cell leukemia originating from large granular lymphocytes (T-LGL leukemia) is a rare lymphoid neoplasia characterized by clonal proliferation of large granular T lymphocytes expressing αß or γδ T-cell receptor (TCR) on the cell membrane. γδT-LGL leukemia, accounting for approximately 17% of all T-LGL leukemia cases, is associated with autoimmune diseases. However, the features of γδT-LGL leukemia in patients with rheumatologic diseases are still insufficiently characterized. Methods: In this retrospective study, 15 patients with rheumatologic disease-associated γδT-LGL leukemia were included. The patients were obtained from a single center from 2008 to 2023. Data related to clinical characteristics and rheumatologic diagnoses were collected. Immunophenotype evaluations as well as T-lymphocyte clonality (based on TCR-γ, TCR-ß, and TCR-δ gene rearrangements), and signal transducer and activator of transcription (STAT) three and STAT5B mutation analyses (by next-generation sequencing) were performed on blood, bone marrow, and spleen samples. Results: All but one patient had rheumatoid arthritis (RA). In 36% of patients, manifestations of γδT-LGL leukemia were present before or concurrently with clinical manifestations of RA. Splenomegaly was observed in 60% of patients and neutropenia (<1.5 × 109/L) was detected in 93% of cases. CD4-/CD8- and CD4-/CD8+ subtypes were detected in seven cases each. Mutations in STAT3 were detected in 80% of patients; however, STAT5B mutations were not detected. Evaluations of T-cell clonality and variant allele frequencies at STAT3 in the blood, bone marrow, and spleen tissue revealed an unusual variant of CD4-/CD8- γδT-LGL leukemia with predominant involvement of the spleen, involvement of the bone marrow to a less extent, and no tumor cells in peripheral blood. Conclusion: The mechanism by which γδT-LGL leukemia may induce the development of RA in some patients requires further investigation. Cases of RA-associated γδT-LGL leukemia with neutropenia and splenomegaly but no detectable tumor-associated lymphocytes in peripheral blood (the so-called splenic variant of T-LGL leukemia) are difficult to diagnose and may be misdiagnosed as Felty syndrome or hepatosplenic T-cell lymphoma.
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OBJECTIVES: Neutropenia is a key presentation of Felty syndrome (FS) and rheumatoid arthritis (RA)-associated T-cell large granular lymphocytic (T-LGL) leukaemia. Clonal rearrangement of T-cell receptor (TCR) gene supports the diagnosis of T-LGL leukaemia but not FS. Mutations in the signal transducer and activator of transcription 3 (STAT3) gene are highly specific for T-LGL leukaemia, but their prevalence in FS remains poorly clarified. METHODS: The study included 100 patients with RA and unexplained neutropenia. TCR rearrangements were examined in blood (100 cases), bone marrow (47 cases), and spleen (12 cases) using the BIOMED-2 protocol. Patients were stratified into RA-associated T-LGL leukaemia cohort if a clonal TCR rearrangement was identified in any of the tested patient samples, and into FS cohort in other cases. Mutations in the STAT3 were examined using next-generation sequencing (NGS) technology in blood (100 cases), bone marrow (37 cases), and spleen (7 cases). RESULTS: STAT3 mutations were identified in 71% (49/69) patients with RA-associated T-LGL leukaemia and in 10% (3/31) patients with FS (p=4.7×10-8). Three samples from the RA-associated T-LGL leukaemia cohort and 5 samples from the FS cohort had STAT3 mutations in the absence of clonal TCR rearrangement. CONCLUSIONS: The results suggest that STAT3 mutations are significantly less common in FS than in RA-associated T-LGL leukaemia. Moreover, NGS can detect clones undetectable by fragment analysis. We speculate that in patients with RA and neutropenia, the detection of STAT3 mutations can point to T-LGL leukaemia even in the absence of clonal TCR rearrangement.
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Artritis Reumatoide , Síndrome de Felty , Leucemia Linfocítica Granular Grande , Neutropenia , Humanos , Leucemia Linfocítica Granular Grande/diagnóstico , Leucemia Linfocítica Granular Grande/epidemiología , Leucemia Linfocítica Granular Grande/genética , Síndrome de Felty/diagnóstico , Síndrome de Felty/epidemiología , Síndrome de Felty/genética , Factor de Transcripción STAT3/genética , Prevalencia , Artritis Reumatoide/diagnóstico , Artritis Reumatoide/epidemiología , Artritis Reumatoide/genética , Receptores de Antígenos de Linfocitos T/genética , MutaciónRESUMEN
Background: Opioids are efficacious and safe analgesic drugs in short-term use for acute pain but chronic use can lead to tolerance and dependence. Opioid-induced microglial activation may contribute to the development of tolerance and this process may differ between males and females. A link is suggested between this microglial activation and inflammation, disturbances of circadian rhythms, and neurotoxic effects. We set out to further delineate the effects of chronic morphine on pain behaviour, microglial and neuronal staining, and the transcriptome of spinal microglia, to better understand the role of microglia in the consequences of long-term high-dose opioid administration. Experimental Approach: In two experiments, we administered increasing subcutaneous doses of morphine hydrochloride or saline to male and female rats. Thermal nociception was assessed with the tail flick and hot plate tests. In Experiment I, spinal cord (SC) samples were prepared for immunohistochemical staining for microglial and neuronal markers. In Experiment II, the transcriptome of microglia from the lumbar SC was analysed. Key Results: Female and male rats had similar antinociceptive responses to morphine and developed similar antinociceptive tolerance to thermal stimuli following chronic increasing high doses of s.c. morphine. The area of microglial IBA1-staining in SC decreased after 2 weeks of morphine administration in both sexes. Following morphine treatment, the differentially expressed genes identified in the microglial transcriptome included ones related to the circadian rhythm, apoptosis, and immune system processes. Conclusions: Female and male rats showed similar pain behaviour following chronic high doses of morphine. This was associated with decreased staining of spinal microglia, suggesting either decreased activation or apoptosis. High-dose morphine administration also associated with several changes in gene expression in SC microglia, e.g., those related to the circadian rhythm (Per2, Per3, Dbp). These changes should be considered in the clinical consequences of long-term high-dose administration of opioids.
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Analgésicos Opioides , Morfina , Ratas , Masculino , Femenino , Animales , Morfina/uso terapéutico , Analgésicos Opioides/farmacología , Analgésicos Opioides/uso terapéutico , Microglía , Transcriptoma/genética , Analgésicos/farmacología , Dolor/metabolismo , Médula Espinal/metabolismoRESUMEN
BT44 is a novel, second-generation glial cell line-derived neurotropic factor mimetic with improved biological activity and is a lead compound for the treatment of neurodegenerative disorders. Like many other small molecules, it suffers from intrinsic poor aqueous solubility, posing significant hurdles at various levels for its preclinical development and clinical translation. Herein, we report a poly(2-oxazoline)s (POx)-based BT44 micellar nanoformulation with an ultrahigh drug-loading capacity of 47 wt %. The BT44 nanoformulation was comprehensively characterized by 1H NMR spectroscopy, differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), dynamic light scattering (DLS), and cryo-transmission/scanning electron microscopy (cryo-TEM/SEM). The DSC, XRD, and redispersion studies collectively confirmed that the BT44 formulation can be stored as a lyophilized powder and can be redispersed upon need. The DLS suggested that the redispersed formulation is suitable for parenteral administration (Dh ≈ 70 nm). The cryo-TEM measurements showed the presence of wormlike structures in both the plain polymer and the BT44 formulation. The BT44 formulation retained biological activity in immortalized cells and in cultured dopamine neurons. The micellar nanoformulation of BT44 exhibited improved absorption (after subcutaneous injection) and blood-brain barrier (BBB) penetration, and no acute toxic effects in mice were observed. In conclusion, herein, we have developed an ultrahigh BT44-loaded aqueous injectable nanoformulation, which can be used to pave the way for its preclinical and clinical development for the management of neurodegenerative disorders.
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Barrera Hematoencefálica , Enfermedades Neurodegenerativas , Animales , Ratones , Polvos , Solubilidad , Difracción de Rayos X , Agua/química , Micelas , Enfermedades Neurodegenerativas/tratamiento farmacológico , Rastreo Diferencial de CalorimetríaRESUMEN
Parkinson's disease (PD) is the most common age-related movement disorder characterized by the progressive loss of nigrostriatal dopaminergic neurons. To date, PD treatment strategies are mostly based on dopamine replacement medicines, which can alleviate motor symptoms but do not slow down the progression of neurodegeneration. Thus, there is a need for disease-modifying PD therapies. The aim of this work was to evaluate the neuroprotective effects of the novel compound PA96 on dopamine neurons in vivo and in vitro, assess its ability to alleviate motor deficits in MPTP- and haloperidol-based PD models, as well as PK profile and BBB penetration. PA96 was synthesized from (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl) cyclohex-3-ene-1,2-diol (Prottremin) using the original three-step stereoselective procedure. We found that PA96: (1) supported the survival of cultured näive dopamine neurons; (2) supported the survival of MPP+-challenged dopamine neurons in vitro and in vivo; (3) had chemically appropriate properties (synthesis, solubility, etc.); (4) alleviated motor deficits in MPTP- and haloperidol-based models of PD; (5) penetrated the blood-brain barrier in vivo; and (6) was eliminated from the bloodstream relative rapidly. In conclusion, the present article demonstrates the identification of PA96 as a lead compound for the future development of this compound into a clinically used drug.
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Intoxicación por MPTP , Fármacos Neuroprotectores , Enfermedad de Parkinson , Animales , Ratones , Humanos , Neuronas Dopaminérgicas , Intoxicación por MPTP/tratamiento farmacológico , Monoterpenos/farmacología , Ratones Endogámicos C57BL , Modelos Animales de Enfermedad , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Enfermedad de Parkinson/tratamiento farmacológico , Haloperidol/farmacología , Sustancia NegraRESUMEN
The relationship between Sjögren syndrome (SS) and T-cell large granular lymphocytic (T-LGL) leukemia remains unclear. In this paper, we report for the first time a large case series of 21 patients with primary and secondary SS associated with T-LGL leukemia. Our results suggest the importance of considering T-LGL leukemia in the diagnostic evaluation of SS patients, particularly when neutropenia occurs. We also postulate that elevated antinuclear antibody titers in patients with T-LGL leukemia indicate the need for the clinical assessment of SS. To assess whether SS affects the frequency of the signal transducer and activator of transcription 3 (STAT3) gene mutations in T-LGL leukemia, we examined STAT3 mutations by next-generation sequencing in two cohorts of patients: with SS-associated T-LGL leukemia and T-LGL leukemia in the setting of rheumatic diseases but without SS. While our results suggest that SS, per se, is not associated with an increased frequency of STAT3 mutations in T-LGL leukemia, further studies are needed to better assess the role of the STAT pathway in the development of concomitant SS and T-LGL leukemia.
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Leucemia Linfocítica Granular Grande , Neutropenia , Síndrome de Sjögren , Humanos , Leucemia Linfocítica Granular Grande/genética , Leucemia Linfocítica Granular Grande/diagnóstico , Síndrome de Sjögren/complicaciones , Síndrome de Sjögren/genética , Mutación , Secuenciación de Nucleótidos de Alto RendimientoRESUMEN
A persistently increased T-cell large granular lymphocyte (T-LGL) count in the blood of more than 2 × 109/L for at least 6 months is necessary for a reliable diagnosis of T-LGL leukemia. In cases with LGL counts of approximately 0.5-2 × 109/L, a diagnosis of T-LGL leukemia can be made if clonal rearrangement of T-cell receptor (TCR) genes is present and if the patient shows typical manifestations of T-LGL leukemia, such as cytopenia, splenomegaly, or concomitant autoimmune disease. However, in cases with LGL counts of less than 0.5 × 109/L, the diagnosis of T-LGL leukemia is questionable (termed as "gray-zone" cases). Although mutations in signal transducer and activator of transcription 3 (STAT3) gene are the molecular hallmark of T-LGL leukemia, their diagnostic value in the "gray-zone" cases of T-LGL leukemia has not been evaluated - our study has been aimed to examine the prevalence of STAT3 mutations in these cases. Herein, we describe 25 patients with autoimmune rheumatic diseases, neutropenia, clonal rearrangement of TCR genes, and circulating LGL count of less than 0.5 × 109/L. Splenomegaly was observed in 19 (76%) patients. Mutations in the STAT3 were detected in 56% of patients using next-generation sequencing. Importantly, in 3 patients, no involvement of the blood and bone marrow by malignant LGLs was noted, but examination of splenic tissue revealed infiltration by clonal cytotoxic T-lymphocytes within the red pulp, with greater prominence in the cords. We suggest using the term "splenic variant of T-LGL leukemia" for such cases.
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Well-known effects of neurotrophic factors are related to supporting the survival and functioning of various neuronal populations in the body. However, these proteins seem to also play less well-documented roles in glial cells, thus, influencing neuroinflammation. This article summarizes available data on the effects of glial cell line derived neurotrophic factor (GDNF) family ligands (GFLs), proteins providing trophic support to dopaminergic, sensory, motor and many other neuronal populations, in non-neuronal cells contributing to the development and maintenance of neuropathic pain. The paper also contains our own limited data describing the effects of small molecules targeting GFL receptors on the expression of the satellite glial marker IBA1 in dorsal root ganglia of rats with surgery- and diabetes-induced neuropathy. In our experiments activation of GFLs receptors with either GFLs or small molecule agonists downregulated the expression of IBA1 in this tissue of experimental animals. While it can be a secondary effect due to a supportive role of GFLs in neuronal cells, growing body of evidence indicates that GFL receptors are expressed in glial and peripheral immune system cells. Thus, targeting GFL receptors with either proteins or small molecules may directly suppress the activation of glial and immune system cells and, therefore, reduce neuroinflammation. As neuroinflammation is considered to be an important contributor to the process of neurodegeneration these data further support research efforts to modulate the activity of GFL receptors in order to develop disease-modifying treatments for neurodegenerative disorders and neuropathic pain that target both neuronal and glial cells.
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T cell large granular lymphocytic (T-LGL) leukemia is a rare type of mature T cell neoplasm. The typical features of T-LGL leukemia include an increased number of large granular lymphocytes in the peripheral blood, cytopenia (most commonly neutropenia), and mild-to-moderate splenomegaly. Up to 28% of patients with T-LGL leukemia have rheumatoid arthritis (RA). This study reports ten atypical cases (seven women and three men, median age 60.5 years) of RA-associated T-LGL leukemia presenting with lymphopenia, severe neutropenia, and marked splenomegaly. The weight of the spleens ranged from 892 to 2100 g (median 1100 g). Bone marrow histology and differential counts of bone marrow aspirates revealed no peculiarities in nine of ten cases. The red pulp of the spleen was expanded and showed moderate to strong infiltration by medium-sized slightly pleomorphic lymphocytes in nine cases and subtle infiltration in one. Although lymphocytic infiltration involved both cords and sinusoids, it was more apparent within the splenic cords. The white pulp was preserved and contained prominent germinal centers in eight patients and was atrophic in two patients. Immunohistochemically, malignant lymphocytes were CD3+, CD43+, and CD4- in all cases and TIA-1+ in nine out of ten. TCRαß positivity and TCRγδ positivity was observed in six and four cases out of ten, respectively. All ten patients had T cell clonality in the spleen tissue, but in three cases it was absent in both blood and bone marrow. STAT3 mutations in the spleen tissue were detected in three of ten cases. In all eight cases studied, neither isochromosome 7q nor trisomy 8 was detected in the spleen tissue. Cases of RA-associated T-LGL leukemia with low LGL count in the peripheral blood, neutropenia, and marked splenomegaly present a diagnostic challenge and can be misdiagnosed as Felty's syndrome or hepatosplenic T cell lymphoma.
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BACKGROUND: Parkinson's disease (PD) is a progressive neurological disorder where loss of dopamine neurons in the substantia nigra and dopamine depletion in the striatum cause characteristic motor symptoms. Currently, no treatment is able to halt the progression of PD. Glial cell line-derived neurotrophic factor (GDNF) rescues degenerating dopamine neurons both in vitro and in animal models of PD. When tested in PD patients, however, the outcomes from intracranial GDNF infusion paradigms have been inconclusive, mainly due to poor pharmacokinetic properties. OBJECTIVE: We have developed drug-like small molecules, named BT compounds that activate signaling through GDNF's receptor, the transmembrane receptor tyrosine kinase RET, both in vitro and in vivo and are able to penetrate through the blood-brain barrier. Here we evaluated the properties of BT44, a second generation RET agonist, in immortalized cells, dopamine neurons and rat 6-hydroxydopamine model of PD. METHODS: We used biochemical, immunohistochemical and behavioral methods to evaluate the effects of BT44 on dopamine system in vitro and in vivo. RESULTS: BT44 selectively activated RET and intracellular pro-survival AKT and MAPK signaling pathways in immortalized cells. In primary midbrain dopamine neurons cultured in serum-deprived conditions, BT44 promoted the survival of the neurons derived from wild-type, but not from RET knockout mice. BT44 also protected cultured wild-type dopamine neurons from MPP+-induced toxicity. In a rat 6-hydroxydopamine model of PD, BT44 reduced motor imbalance and seemed to protect dopaminergic fibers in the striatum. CONCLUSION: BT44 holds potential for further development into a novel, possibly disease-modifying, therapy for PD.
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Fármacos Neuroprotectores , Enfermedad de Parkinson , Animales , Dopamina , Neuronas Dopaminérgicas/metabolismo , Factor Neurotrófico Derivado de la Línea Celular Glial , Humanos , Ratones , Fármacos Neuroprotectores/farmacología , Oxidopamina/toxicidad , Proteínas Proto-Oncogénicas c-ret , Ratas , Sustancia Negra/metabolismoRESUMEN
T-cell large granular lymphocytic leukemia (T-LGLL) is a lymphoproliferative disorder characterized by a persistent increase in the number of large granular lymphocytes (LGLs), neutropenia, and splenomegaly. Clinical manifestations of T-LGLL in the setting of rheumatoid arthritis (RA) are often identical to those in which one would suspect Felty's syndrome (FS). These disorders are distinguished by the presence of T-cell clonality, which is present in T-LGLL but not in FS. Mutations in the signal transducer and activator of transcription 3 (STAT3) and 5b (STAT5b) genes can be used as molecular markers of T-LGLL, but their prevalence in FS is unknown.Eighty-one patients with RA and unexplained neutropenia or/and an increase in the number of LGLs above 2 × 109/L were stratified into RA-associated T-LGLL (N = 56) or FS (N = 25) groups based on the presence or absence of T-cell clonality. STAT3 and STAT5b gene mutations were assessed in each group by means of allele-specific polymerase chain reaction assays. Clinical, immunological, laboratory data and the results of immunophenotyping of blood and bone marrow lymphocytes were also evaluated.Mutations of the STAT3 gene and an increase in the number of LGLs above 2 × 109/L were detected in RA-associated T-LGLL, but not in FS (39% vs 0% and 21% vs 0%, respectively). Mutations in the STAT5b gene were not observed in either group. Expression of CD57, CD16, and CD5-/dim on CD3+CD8+ T-lymphocytes was observed in both RA-associated T-LGLL and FS.STAT3 gene mutations or LGL counts over 2 × 109/L in RA patients are indicative of T-LGLL.
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Artritis Reumatoide/complicaciones , Leucemia Linfocítica Granular Grande/genética , Adulto , Biomarcadores de Tumor/genética , Células de la Médula Ósea/patología , Diagnóstico Diferencial , Síndrome de Felty/diagnóstico , Síndrome de Felty/genética , Femenino , Humanos , Leucemia Linfocítica Granular Grande/complicaciones , Leucemia Linfocítica Granular Grande/diagnóstico , Masculino , Persona de Mediana Edad , Mutación , Neutropenia , Estudios Retrospectivos , Factor de Transcripción STAT3 , Factor de Transcripción STAT5RESUMEN
Growth factors (GFs) hold considerable promise for disease modification in neurodegenerative disorders because they can protect and restore degenerating neurons and also enhance their functional activity. However, extensive efforts applied to utilize their therapeutic potential in humans have achieved limited success so far. Multiple clinical trials with GFs were performed in Parkinson's disease (PD) patients, in whom diagnostic symptoms of the disease are caused by advanced degeneration of nigrostriatal dopamine neurons (DNs), but the results of these trials are controversial. This review discusses recent developments in the field of therapeutic use of GFs, problems and obstacles related to this use, suggests the ways to overcome these issues, and alternative approaches that can be used to utilize the potential ofGFsin PD management.
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Péptidos y Proteínas de Señalización Intercelular , Enfermedades Neurodegenerativas , Enfermedad de Parkinson , Neuronas Dopaminérgicas , Humanos , Péptidos y Proteínas de Señalización Intercelular/uso terapéutico , Enfermedad de Parkinson/tratamiento farmacológicoRESUMEN
The peculiar features of T-cell large granular lymphocytic leukemia (T-LGLL) are its association with autoimmune disorders (particularly with rheumatoid arthritis (RA)) and a broad spectrum of B-cell lymphoproliferative disorders. However, association of T-LGLL with mantle cell lymphoma (MCL) is extremely rare. Here, we describe a case of an 80-year-old man admitted with suspected Felty's syndrome. The blood count showed white blood cells at 2.2×109/L, with 3% neutrophils, 88% lymphocytes, and at 0.66×109/L LGLs. The spleen had been removed 43 months prior to the admission due to suspected B-cell splenic lymphoma. Re-examination of the spleen revealed cyclin D1+ and SOX11- lymphocytes in the inner part of the unexpanded mantle zones of the white pulp follicles, thus displaying a so-called in situ histologic pattern of MCL, and in small clusters in the red pulp. The splenic cords were moderately expanded by lymphocytes expressing CD3, TIA1, and granzyme B but not CD4 and CD8. Monoclonal rearrangements of the immunoglobulin heavy chain gene and the T-cell receptor (TCR) gamma and delta chain genes, polyclonal rearrangements of the TCR beta chain gene, mutation of the signal transducer and activator of transctiption 3 gene (c.1940A>T; p.N647I), and t(11;14)(q13;q32) translocation were identified in the spleen sample. Flow cytometry of bone marrow revealed a population of TCR γδ+, CD3+, CD4-, CD5-, CD7+, CD8-, CD16-, CD56-, and CD57- lymphocytes. Fragment analysis demonstrated identical TCR gene clonal rearrangement patterns in the spleen and bone marrow samples. In this study, we describe the first case of simultaneous presentation of γδ T-LGLL and leukemic non-nodal MCL (L-NN-MCL) in a patient with RA and present morphological findings of L-NN-MCL in the spleen.
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Rearranged during transfection (RET) is the tyrosine kinase receptor that under normal circumstances interacts with ligand at the cell surface and mediates various essential roles in a variety of cellular processes such as proliferation, differentiation, survival, migration, and metabolism. RET plays a pivotal role in the development of both peripheral and central nervous systems. RET is expressed from early stages of embryogenesis and remains expressed throughout all life stages. Mutations either activating or inhibiting RET result in several aggressive diseases, namely cancer and Hirschsprung disease. However, the physiological ligand-dependent activation of RET receptor is important for the survival and maintenance of several neuronal populations, appetite, and weight gain control, thus providing an opportunity for the development of disease-modifying therapeutics against neurodegeneration and obesity. In this review, we describe the structure of RET, its signaling, and its role in both normal conditions as well as in several disorders. We highlight the differences in the signaling and outcomes of constitutive and ligand-induced RET activation. Finally, we review the data on recently developed small molecular weight RET agonists and their potential for the treatment of various diseases.
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Neoplasias/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Obesidad/metabolismo , Proteínas Proto-Oncogénicas c-ret/metabolismo , Animales , Enfermedad de Hirschsprung/genética , Enfermedad de Hirschsprung/metabolismo , Enfermedad de Hirschsprung/patología , Humanos , Mutación , Neoplasias/genética , Neoplasias/patología , Enfermedades Neurodegenerativas/genética , Enfermedades Neurodegenerativas/patología , Neuronas/metabolismo , Neuronas/patología , Obesidad/genética , Obesidad/patología , Proteínas Proto-Oncogénicas c-ret/análisis , Proteínas Proto-Oncogénicas c-ret/genética , Retinitis Pigmentosa/genética , Retinitis Pigmentosa/metabolismo , Retinitis Pigmentosa/patologíaRESUMEN
Oxidative stress is prominent in many neurodegenerative diseases. Along with mitochondrial dysfunction and pathological protein aggregation, increased levels of reactive oxygen and nitrogen species, together with impaired antioxidant defense mechanisms, are frequently observed in Alzheimer's, Parkinson's, Huntington's disease and amyotrophic lateral sclerosis. The presence of oxidative stress markers in patients' plasma and cerebrospinal fluid may aid early disease diagnoses, as well as provide clues regarding the efficacy of experimental disease-modifying therapies in clinical trials. In preclinical animal models, the detection and localization of oxidatively damaged lipids, proteins and nucleic acids helps to identify most vulnerable neuronal populations and brain areas, and elucidate the molecular pathways and the timeline of pathology progression. Here, we describe the protocol for the detection of oxidative stress markers using immunohistochemistry on formaldehyde-fixed, paraffin-embedded tissue sections, applicable to the analysis of postmortem samples and tissues from animal models. In addition, we provide a simple method for the detection of malondialdehyde in tissue lysates and body fluids, which is useful for screening and the identification of tissues and structures in the nervous system which are most affected by oxidative stress.
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Glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) are able to promote the survival of multiple neuronal populations in the body and, therefore, hold considerable promise for disease-modifying treatments of diseases and conditions caused by neurodegeneration. Available data reveal the potential of GFLs for the therapy of Parkinson's disease, neuropathic pain and diseases caused by retinal degeneration but, also, amyotrophic lateral sclerosis and, possibly, Alzheimer's disease. Despite promising data collected in preclinical models, clinical translation of GFLs is yet to be conducted. The main reasons for the limited success of GFLs clinical development are the poor pharmacological characteristics of GFL proteins, such as the inability of GFLs to cross tissue barriers, poor diffusion in tissues, biphasic dose-response and activation of several receptors in the organism in different cell types, along with ethical limitations on patients' selection in clinical trials. The development of small molecules selectively targeting particular GFL receptors with improved pharmacokinetic properties can overcome many of the difficulties and limitations associated with the clinical use of GFL proteins. The current review lists several strategies to target the GFL receptor complex with drug-like molecules, discusses their advantages, provides an overview of available chemical scaffolds and peptides able to activate GFL receptors and describes the effects of these molecules in cultured cells and animal models.
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Sistemas de Liberación de Medicamentos/métodos , Receptores del Factor Neurotrófico Derivado de la Línea Celular Glial/efectos de los fármacos , Péptidos/farmacología , Animales , Células Cultivadas , Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Receptores del Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Humanos , Ligandos , Neuralgia/metabolismo , Neuritas/metabolismo , Enfermedades Neurodegenerativas/tratamiento farmacológico , Neuroglía/efectos de los fármacos , Neuroglía/metabolismo , Neuronas/metabolismo , Receptores de Factor de Crecimiento Nervioso/efectos de los fármacos , Receptores de Factor de Crecimiento Nervioso/metabolismo , Transducción de Señal/efectos de los fármacos , Bibliotecas de Moléculas Pequeñas/farmacologíaRESUMEN
The glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) alleviate symptoms of experimental neuropathy, protect and stimulate regeneration of sensory neurons in animal models of neuropathic pain, and restore their functional activity. However, clinical development of GFL proteins is complicated by their poor pharmacokinetic properties and multiple effects mediated by several receptors. Previously, we have identified a small molecule that selectively activates the major signal transduction unit of the GFL receptor complex, receptor tyrosine kinase RET, as an alternative to GFLs, for the treatment of neuropathic pain. We then introduced a series of chemical changes to improve the biological activity of these compounds and tested an optimized compound named BT44 in a panel of biological assays. BT44 efficiently and selectively stimulated the GFL receptor RET and activated the intracellular mitogene-activated protein kinase/extracellular signal-regulated kinase pathway in immortalized cells. In cultured sensory neurons, BT44 stimulated neurite outgrowth with an efficacy comparable to that of GFLs. BT44 alleviated mechanical hypersensitivity in surgery- and diabetes-induced rat models of neuropathic pain. In addition, BT44 normalized, to a certain degree, the expression of nociception-related neuronal markers which were altered by spinal nerve ligation, the neuropathy model used in this study. Our results suggest that the GFL mimetic BT44 is a promising new lead for the development of novel disease-modifying agents for the treatment of neuropathy and neuropathic pain.
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Biomimética/métodos , Neuralgia/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-ret/agonistas , Proteínas Proto-Oncogénicas c-ret/metabolismo , Células Receptoras Sensoriales/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Nervios Espinales/efectos de los fármacos , Animales , Escala de Evaluación de la Conducta , Línea Celular , Neuropatías Diabéticas/tratamiento farmacológico , Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Receptores del Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Factores Neurotróficos Derivados de la Línea Celular Glial , Inmunohistoquímica , Masculino , Proteínas del Tejido Nervioso/metabolismo , Neuralgia/metabolismo , Nocicepción/efectos de los fármacos , Fosforilación , Ratas , Ratas Wistar , Células Receptoras Sensoriales/metabolismo , Nervios Espinales/lesionesRESUMEN
Rearranged during transfection (RET), in complex with glial cell line-derived (GDNF) family receptor alpha (GFRα), is the canonical signaling receptor for GDNF family ligands (GFLs) expressed in both central and peripheral parts of the nervous system and also in non-neuronal tissues. RET-dependent signaling elicited by GFLs has an important role in the development, maintenance and survival of dopamine and sensory neurons. Both Parkinson's disease and neuropathic pain are devastating disorders without an available cure, and at the moment are only treated symptomatically. GFLs have been studied extensively in animal models of Parkinson's disease and neuropathic pain with remarkable outcomes. However, clinical trials with recombinant or viral vector-encoded GFL proteins have produced inconclusive results. GFL proteins are not drug-like; they have poor pharmacokinetic properties and activate multiple receptors. Targeting RET and/or GFRα with small molecules may resolve the problems associated with using GFLs as drugs and can result in the development of therapeutics for disease-modifying treatments against Parkinson's disease and neuropathic pain.
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Neuralgia/terapia , Enfermedad de Parkinson/genética , Proteínas Proto-Oncogénicas c-ret/genética , Animales , Diseño de Fármacos , Humanos , Ratones , Transducción de SeñalRESUMEN
Glial cell line-derived neurotrophic factor (GDNF) binds the GFRα1 receptor, and the GDNF-GFRα1 complex binds to and activates the transmembrane RET tyrosine kinase to signal through intracellular Akt/Erk pathways. To dissect the GDNF-GFRα1-RET signaling complex, agents that bind and activate RET directly and independently of GFRα1 expression are valuable tools. In a focused naphthalenesulfonic acid library from the National Cancer Institute database, we identified small molecules that are genuine ligands binding to the RET extracellular domain. These ligands activate RET tyrosine kinase and afford trophic signals irrespective of GFRα1 coexpression. However, RET activation by these ligands is constrained by GFRα1, likely via an allosteric mechanism that can be overcome by increasing RET ligand concentration. In a mouse model of retinitis pigmentosa, monotherapy with a small-molecule RET agonist activates survival signals and reduces neuronal death significantly better than GDNF, suggesting therapeutic potential. SIGNIFICANCE STATEMENT: A genuine ligand of RET receptor ectodomain was identified, which acts as an agonist. Binding and agonism are independent of a coreceptor glial cell line-derived neurotrophic factor family receptor α, which is required by the natural growth factor glial cell line-derived neurotrophic factor, and are selective for cells expressing RET. The lead agent protects neurons from death in vivo. This work validates RET receptor as a druggable therapeutic target and provides for potential leads to evaluate in neurodegenerative states. We also report problems that arise when screening chemical libraries.
Asunto(s)
Receptores del Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Naftalenosulfonatos/administración & dosificación , Proteínas Proto-Oncogénicas c-ret/química , Proteínas Proto-Oncogénicas c-ret/metabolismo , Retinitis Pigmentosa/tratamiento farmacológico , Bibliotecas de Moléculas Pequeñas/farmacología , Regulación Alostérica , Animales , Apoptosis/efectos de los fármacos , Línea Celular , Modelos Animales de Enfermedad , Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Humanos , Ligandos , Ratones , Naftalenosulfonatos/farmacología , Dominios Proteicos , Proteínas Proto-Oncogénicas c-ret/agonistas , Retinitis Pigmentosa/metabolismo , Transducción de Señal , Bibliotecas de Moléculas Pequeñas/administración & dosificaciónRESUMEN
Glial cell line-derived neurotrophic factor (GDNF) is a growth factor that regulates the health and function of neurons and other cells. GDNF binds to GDNF family receptor α1 (GFRa1), and the resulting complex activates the RET receptor tyrosine kinase and subsequent downstream signals. This feature restricts GDNF activity to systems in which GFRa1 and RET are both present, a scenario that may constrain GDNF breadth of action. Furthermore, this co-dependence precludes the use of GDNF as a tool to study a putative functional cross-talk between GFRa1 and RET. Here, using biochemical techniques, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and immunohistochemistry in murine cells, tissues, or retinal organotypic cultures, we report that a naphthoquinone/quinolinedione family of small molecules (Q compounds) acts as RET agonists. We found that, like GDNF, signaling through the parental compound Q121 is GFRa1-dependent. Structural modifications of Q121 generated analogs that activated RET irrespective of GFRa1 expression. We used these analogs to examine RET-GFRa1 interactions and show that GFRa1 can influence RET-mediated signaling and enhance or diminish AKT Ser/Thr kinase or extracellular signal-regulated kinase signaling in a biased manner. In a genetic mutant model of retinitis pigmentosa, a lead compound, Q525, afforded sustained RET activation and prevented photoreceptor neuron loss in the retina. This work uncovers key components of the dynamic relationships between RET and its GFRa co-receptor and provides RET agonist scaffolds for drug development.