RESUMO
Medical evaluation for military applicants is an intricate process that requires an understanding of the terminology, standards, and guidelines. Allergy providers are often called to provide medical evaluations for patients who desire to join the military services. Without understanding the complexities and nuances of military medical evaluations, a provider may delay or not be able to assist their patient in obtaining the desired goal of joining the services. This article reviews the terminology of military medical evaluations and the guidelines and processes for these evaluations. We also focus our discussion on common allergic conditions that may be disqualifying for service and provide expert opinions of the subtleties of these conditions to provide the allergist with a practical approach to medical evaluations. Finally, we provide a list of resources that are accessible to any provider engaged in military medical evaluations for accessions.
Assuntos
Hipersensibilidade , Militares , Humanos , Hipersensibilidade/diagnóstico , Guias de Prática Clínica como AssuntoRESUMO
BACKGROUND: Sesame allergy has been characterized in the Middle East for some time. However, it has become more widely recognized as foods containing sesame and sesame seeds have become increasingly available in Australia, Europe, and North America. With the passage of the Food Allergy Safety, Treatment, Education, and Research Act in 2021, the United States will join other countries in identifying sesame as a major food allergen and require sesame to be labeled as a food allergen beginning in 2023. OBJECTIVE: To review the literature related to sesame allergy as an increasingly recognized food allergen around the world. DATA SOURCES: English-language articles retrieved by PubMed searches with relevance to sesame allergy. STUDY SELECTIONS: Articles were included using the search terms "sesame allergy" and "sesame seed allergy." RESULTS: A total of 69 relevant articles regarding sesame allergy, relating to its prevalence, clinical presentation, natural history, allergenic epitopes, diagnosis, and treatment, were selected. CONCLUSION: In recent decades, considerable gains have been made in determining prevalence and natural history of sesame allergy. With increased recognition and prevalence come the need for reliable methods of identification of sesame allergy and approaches for management.
Assuntos
Hipersensibilidade Alimentar , Sesamum , Humanos , Alérgenos , Sesamum/efeitos adversos , Hipersensibilidade Alimentar/diagnóstico , Hipersensibilidade Alimentar/epidemiologia , Hipersensibilidade Alimentar/terapia , Europa (Continente) , América do Norte/epidemiologiaRESUMO
Glioblastoma multiforme (GBM) is the most deadly brain tumor, and currently lacks effective treatment options. Brain tumor-initiating cells (BTICs) and orthotopic xenografts are widely used in investigating GBM biology and new therapies for this aggressive disease. However, the genomic characteristics and molecular resemblance of these models to GBM tumors remain undetermined. We used massively parallel sequencing technology to decode the genomes and transcriptomes of BTICs and xenografts and their matched tumors in order to delineate the potential impacts of the distinct growth environments. Using data generated from whole-genome sequencing of 201 samples and RNA sequencing of 118 samples, we show that BTICs and xenografts resemble their parental tumor at the genomic level but differ at the mRNA expression and epigenomic levels, likely due to the different growth environment for each sample type. These findings suggest that a comprehensive genomic understanding of in vitro and in vivo GBM model systems is crucial for interpreting data from drug screens, and can help control for biases introduced by cell-culture conditions and the microenvironment in mouse models. We also found that lack of MGMT expression in pretreated GBM is linked to hypermutation, which in turn contributes to increased genomic heterogeneity and requires new strategies for GBM treatment.
Assuntos
Biomarcadores Tumorais/genética , Neoplasias Encefálicas/patologia , Regulação Neoplásica da Expressão Gênica , Genômica/métodos , Glioblastoma/patologia , Células-Tronco Neoplásicas/patologia , Microambiente Tumoral/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Apoptose , Neoplasias Encefálicas/genética , Estudos de Casos e Controles , Proliferação de Células , Metilação de DNA , Resistencia a Medicamentos Antineoplásicos , Feminino , Perfilação da Expressão Gênica , Glioblastoma/genética , Humanos , Masculino , Camundongos , Camundongos SCID , Pessoa de Meia-Idade , Células-Tronco Neoplásicas/metabolismo , Transcriptoma , Células Tumorais Cultivadas , Sequenciamento Completo do Genoma , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Astrocytic brain tumours, including glioblastomas, are incurable neoplasms characterized by diffusely infiltrative growth. Here we show that many tumour cells in astrocytomas extend ultra-long membrane protrusions, and use these distinct tumour microtubes as routes for brain invasion, proliferation, and to interconnect over long distances. The resulting network allows multicellular communication through microtube-associated gap junctions. When damage to the network occurred, tumour microtubes were used for repair. Moreover, the microtube-connected astrocytoma cells, but not those remaining unconnected throughout tumour progression, were protected from cell death inflicted by radiotherapy. The neuronal growth-associated protein 43 was important for microtube formation and function, and drove microtube-dependent tumour cell invasion, proliferation, interconnection, and radioresistance. Oligodendroglial brain tumours were deficient in this mechanism. In summary, astrocytomas can develop functional multicellular network structures. Disconnection of astrocytoma cells by targeting their tumour microtubes emerges as a new principle to reduce the treatment resistance of this disease.
Assuntos
Astrocitoma/patologia , Neoplasias Encefálicas/patologia , Junções Comunicantes/metabolismo , Animais , Astrocitoma/metabolismo , Astrocitoma/radioterapia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/radioterapia , Comunicação Celular/efeitos da radiação , Morte Celular/efeitos da radiação , Proliferação de Células/efeitos da radiação , Extensões da Superfície Celular/metabolismo , Extensões da Superfície Celular/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , Conexina 43/metabolismo , Progressão da Doença , Proteína GAP-43/metabolismo , Junções Comunicantes/efeitos da radiação , Glioma/metabolismo , Glioma/patologia , Glioma/radioterapia , Humanos , Masculino , Camundongos , Camundongos Nus , Invasividade Neoplásica , Tolerância a Radiação/efeitos dos fármacosRESUMO
The PI3K/AKT/mTOR pathway activation plays a central role in glioblastoma multiforme (GBM) development and progression, and in resistance to anti-cancer therapies. Inhibition of the PI3K pathway has been shown to sensitize cultured glioma cells and tumor xenografts to the effects of temozolomide (TMZ) and radiation. Vistusertib is an oral inhibitor of mTORC1/2 complexes. The primary objective of this Canadian Cancer Trials Group phase I study was to determine the recommended phase II dose (RP2D) of vistusertib in patients with GBM receiving TMZ at first progression following primary treatment. Vistusertib was administered at a starting dose of 100 mg bid 2 days on/5 days off weekly with TMZ 150 mg/m2 daily for 5 days/28-days cycle. Dose escalation was according to a 3 + 3 design. Secondary objectives included assessment of vistusertib safety and toxicity profile, and preliminary efficacy. 15 patients were enrolled in the study (median age 66 (range 51-77), females 8). Vistusertib 125 mg BID in combination with TMZ 150 mg/m2 daily for 5 days was well tolerated. Vistusertib treatment-related adverse events were generally grade 1-2, with the most frequently reported being fatigue, gastrointestinal symptoms, and rash. Of 13 response evaluable patients, 1 patient (8%) had a partial response ongoing at 7.6 months of follow-up, and 5 patients had stable disease (38%) as best response (median duration 9.6 months, range 3.7-not yet reached). Six-month progression-free survival (PFS) rate was 26.6%. Combination of vistusertib with TMZ in GBM patients at first recurrence demonstrated a favorable safety profile at the tested dose levels.
Assuntos
Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Benzamidas/administração & dosagem , Neoplasias Encefálicas/tratamento farmacológico , Glioblastoma/tratamento farmacológico , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Alvo Mecanístico do Complexo 2 de Rapamicina/antagonistas & inibidores , Morfolinas/administração & dosagem , Pirimidinas/administração & dosagem , Temozolomida/administração & dosagem , Idoso , Antineoplásicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Benzamidas/efeitos adversos , Feminino , Humanos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Morfolinas/efeitos adversos , Pirimidinas/efeitos adversos , Temozolomida/efeitos adversosRESUMO
IDH1 mutation is the earliest genetic alteration in low-grade gliomas (LGGs), but its role in tumor recurrence is unclear. Mutant IDH1 drives overproduction of the oncometabolite d-2-hydroxyglutarate (2HG) and a CpG island (CGI) hypermethylation phenotype (G-CIMP). To investigate the role of mutant IDH1 at recurrence, we performed a longitudinal analysis of 50 IDH1 mutant LGGs. We discovered six cases with copy number alterations (CNAs) at the IDH1 locus at recurrence. Deletion or amplification of IDH1 was followed by clonal expansion and recurrence at a higher grade. Successful cultures derived from IDH1 mutant, but not IDH1 wild type, gliomas systematically deleted IDH1 in vitro and in vivo, further suggestive of selection against the heterozygous mutant state as tumors progress. Tumors and cultures with IDH1 CNA had decreased 2HG, maintenance of G-CIMP, and DNA methylation reprogramming outside CGI. Thus, while IDH1 mutation initiates gliomagenesis, in some patients mutant IDH1 and 2HG are not required for later clonal expansions.
Assuntos
Epigenômica , Amplificação de Genes , Glioma/genética , Isocitrato Desidrogenase/genética , Mutação , Recidiva Local de Neoplasia/genética , Deleção de Sequência , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Variações do Número de Cópias de DNA , Metilação de DNA , Perfilação da Expressão Gênica , Glioma/patologia , Glutaratos/metabolismo , Humanos , Isocitrato Desidrogenase/metabolismo , Recidiva Local de Neoplasia/metabolismo , Recidiva Local de Neoplasia/patologia , Células Tumorais CultivadasRESUMO
The identification of succinate dehydrogenase (SDH), fumarate hydratase (FH) and isocitrate dehydrogenase (IDH) mutations in human cancers has rekindled the idea that altered cellular metabolism can transform cells. Inactivating SDH and FH mutations cause the accumulation of succinate and fumarate, respectively, which can inhibit 2-oxoglutarate (2-OG)-dependent enzymes, including the EGLN prolyl 4-hydroxylases that mark the hypoxia inducible factor (HIF) transcription factor for polyubiquitylation and proteasomal degradation. Inappropriate HIF activation is suspected of contributing to the pathogenesis of SDH-defective and FH-defective tumours but can suppress tumour growth in some other contexts. IDH1 and IDH2, which catalyse the interconversion of isocitrate and 2-OG, are frequently mutated in human brain tumours and leukaemias. The resulting mutants have the neomorphic ability to convert 2-OG to the (R)-enantiomer of 2-hydroxyglutarate ((R)-2HG). Here we show that (R)-2HG, but not (S)-2HG, stimulates EGLN activity, leading to diminished HIF levels, which enhances the proliferation and soft agar growth of human astrocytes. These findings define an enantiomer-specific mechanism by which the (R)-2HG that accumulates in IDH mutant brain tumours promotes transformation and provide a justification for exploring EGLN inhibition as a potential treatment strategy.
Assuntos
Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/metabolismo , Dioxigenases/metabolismo , Glutaratos/química , Glutaratos/farmacologia , Proteínas Nucleares/metabolismo , Pró-Colágeno-Prolina Dioxigenase/metabolismo , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Dioxigenases/genética , Ativação Enzimática/efeitos dos fármacos , Glioma/enzimologia , Glioma/genética , Glioma/metabolismo , Glioma/patologia , Glutaratos/metabolismo , Humanos , Fator 1 Induzível por Hipóxia/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Proteínas Nucleares/genética , Oncogenes , Pró-Colágeno-Prolina Dioxigenase/genéticaRESUMO
Previous work has demonstrated that the hormone prolactin promotes oligodendrocyte precursor proliferation and remyelination following lysolecithin-induced demyelination of the mouse spinal cord. Prolactin, however, can elicit pro-inflammatory responses, and its use in the prototypical demyelinating and inflammatory condition, multiple sclerosis (MS), should thus be approached cautiously. Here, we sought to determine whether recombinant prolactin could alter the course of experimental autoimmune encephalomyelitis (EAE), an inflammatory animal model of MS. Consistent with previous literature, we found that prolactin activated leukocytes in vitro. Daily treatment with prolactin from around the time of onset of clinical signs, for 9 (days 9 to 17) or 25 (days 9 to 33) days did not increase clinical or histological signs of EAE over that of vehicle-treated mice. Instead, the combination of prolactin and a suboptimal dose of recombinant murine interferon-ß resulted in (days 9 to 17 group) or trended towards (days 9 to 33 group), a greater amelioration of clinical signs of EAE, compared to either treatment alone or to vehicle controls. Histological analyses corroborated the clinical EAE data. These results suggest that prolactin may be beneficial when administered in combination with interferon-ß in MS.
Assuntos
Fatores Imunológicos/uso terapêutico , Interferon beta/uso terapêutico , Esclerose Múltipla/tratamento farmacológico , Prolactina/uso terapêutico , Animais , Células Apresentadoras de Antígenos/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Quimioterapia Combinada , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/induzido quimicamente , Esclerose Múltipla/patologia , Glicoproteína Mielina-Oligodendrócito/toxicidade , Fragmentos de Peptídeos/toxicidade , Medula Espinal/patologia , Fatores de TempoRESUMO
There is increasing pressure for neuroscientists to communicate their research and the societal implications of their findings to the public. Communicating science is challenging, and the transformation of communication by digital and interactive media increases the complexity of the challenge. To facilitate dialogue with the public in this new media landscape, we suggest three courses of action for the neuroscience community: a cultural shift that explicitly recognizes and rewards public outreach, the identification and development of neuroscience communication experts, and ongoing empirical research on the public communication of neuroscience.
Assuntos
Comunicação , Relações Interprofissionais , Neurociências , Pesquisadores , Animais , Humanos , Relações InterinstitucionaisRESUMO
A population of neural stem cells (NSCs) resides adjacent to the lateral ventricles in the adult mammalian brain. Despite knowledge of their existence since the early 1990s, their identity remains controversial, with evidence suggesting that they may be ependymal cells, glial fibrillary acidic protein (GFAP)-expressing subventricular zone (SVZ) cells or several distinct NSC populations. This issue has major implications for the therapeutic use of NSCs as well as for the study and treatment of brain cancers. Recent studies have both shed light on the issue and added to the controversy.
Assuntos
Células-Tronco Adultas/metabolismo , Ventrículos Cerebrais/citologia , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Animais , Astrócitos/metabolismo , Biomarcadores/metabolismo , Epêndima/citologia , Epêndima/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Modelos BiológicosRESUMO
Delayed pressure urticaria (DPU) is a subset of chronic inducible urticaria. It is characterized by the formation of wheals anytime between 30 minutes and 24 hours after stimulus exposure of localized pressure application. In this case report, we discuss a military flight crew member with no significant past medical history who developed DPU following rapid decompression in an altitude chamber. The chamber training included an uneventful ascent to 45,000 feet, higher than he had been previously, and a rapid decompression. About 16 hours later, he developed pruritic swelling of his hands and feet, along with diffuse deep nodular swelling, erythematous plaques, and erythematous nodules. His DPU was refractory to monotherapy treatment with antihistamines, and he continued to develop lesions in weight-bearing areas. Control of symptoms was achieved through combination treatment of a second-generation antihistamine, a leukotriene receptor antagonist, and an immunosuppressant (cyclosporine). His waiver to return to flight status was denied while on cyclosporine. He was transitioned to a monoclonal antibody that binds free immunoglobin E (omalizumab) with resolution of symptoms and was cleared to return to active duty.
RESUMO
Oligodendroglioma is characterized by mutations of IDH and CIC, 1p/19q loss, and slow growth. We found that NHE-1 on 1p is silenced in oligodendrogliomas secondary to IDH-associated hypermethylation and 1p allelic loss. Silencing lowers intracellular pH and attenuates acid load recovery in oligodendroglioma cells. Others have shown that rapid tumor growth cannot occur without NHE-1-mediated neutralization of the acidosis generated by the Warburg glycolytic shift. Our findings show for the first time that the pH regulator NHE-1 can be silenced in a human cancer and also suggest that pH deregulation may contribute to the distinctive biology of human oligodendroglioma.
Assuntos
Neoplasias Encefálicas/genética , Deleção Cromossômica , Cromossomos Humanos Par 1/genética , Metilação de DNA , Mutação/genética , Oligodendroglioma/genética , Trocadores de Sódio-Hidrogênio/genética , Neoplasias Encefálicas/patologia , Humanos , Oligodendroglioma/patologia , Prótons , Células Tumorais CultivadasRESUMO
Multiple sclerosis (MS) is more common among women than men. MS often goes into remission during pregnancy, when prolactin (PRL) levels are known to be high. In an animal model of demyelination, PRL promoted myelin repair, suggesting it has potential as a remyelinating therapy in MS. In this systematic review, we examined the known associations between PRL and MS, in order to elucidate its potential role in the pathophysiology and treatment of MS. A systematic search was performed in the electronic databases PubMed and EMBASE, using the keywords "prolactin" AND "multiple sclerosis." The inclusion criteria were met by 23 studies. These studies suggested to us that elevated PRL may be more common in MS patients than in controls. Hyperprolactinemia may also be associated with clinical relapse in MS, especially among patients with hypothalamic lesions or optic neuritis; however, it is unknown if this is a cause or consequence of a relapse. Overall, most people with MS have normal PRL levels. The impact of PRL on MS outcomes remains unclear.
Assuntos
Esclerose Múltipla/sangue , Prolactina/sangue , Animais , Feminino , Humanos , MasculinoRESUMO
Oligodendroglioma is characterized by unique clinical, pathological, and genetic features. Recurrent losses of chromosomes 1p and 19q are strongly associated with this brain cancer but knowledge of the identity and function of the genes affected by these alterations is limited. We performed exome sequencing on a discovery set of 16 oligodendrogliomas with 1p/19q co-deletion to identify new molecular features at base-pair resolution. As anticipated, there was a high rate of IDH mutations: all cases had mutations in either IDH1 (14/16) or IDH2 (2/16). In addition, we discovered somatic mutations and insertions/deletions in the CIC gene on chromosome 19q13.2 in 13/16 tumours. These discovery set mutations were validated by deep sequencing of 13 additional tumours, which revealed seven others with CIC mutations, thus bringing the overall mutation rate in oligodendrogliomas in this study to 20/29 (69%). In contrast, deep sequencing of astrocytomas and oligoastrocytomas without 1p/19q loss revealed that CIC alterations were otherwise rare (1/60; 2%). Of the 21 non-synonymous somatic mutations in 20 CIC-mutant oligodendrogliomas, nine were in exon 5 within an annotated DNA-interacting domain and three were in exon 20 within an annotated protein-interacting domain. The remaining nine were found in other exons and frequently included truncations. CIC mutations were highly associated with oligodendroglioma histology, 1p/19q co-deletion, and IDH1/2 mutation (p < 0.001). Although we observed no differences in the clinical outcomes of CIC mutant versus wild-type tumours, in a background of 1p/19q co-deletion, hemizygous CIC mutations are likely important. We hypothesize that the mutant CIC on the single retained 19q allele is linked to the pathogenesis of oligodendrogliomas with IDH mutation. Our detailed study of genetic aberrations in oligodendroglioma suggests a functional interaction between CIC mutation, IDH1/2 mutation, and 1p/19q co-deletion.
Assuntos
Biomarcadores Tumorais/genética , Neoplasias Encefálicas/genética , Isocitrato Desidrogenase/genética , Oligodendroglioma/genética , Proteínas Repressoras/genética , Biomarcadores Tumorais/análise , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Cromossomos Humanos Par 1/genética , Cromossomos Humanos Par 19/genética , Intervalo Livre de Doença , Humanos , Estimativa de Kaplan-Meier , Mutação , Gradação de Tumores , Oligodendroglioma/mortalidade , Oligodendroglioma/patologiaRESUMO
We present the case of a patient who was unable to tolerate rapid drug desensitization protocol to receive a continuous penicillin (PCN) G infusion for the treatment of neurosyphilis. A 38-year-old male with past medical history for human immunodeficiency virus, migraines, PCN allergy, doxycycline allergy, shellfish allergy, and untreated latent syphilis presented to the emergency room for a posterior migraine with associated nausea, vomiting, photophobia, right-sided paresthesias, and "shaky" vision. He was diagnosed with neurosyphilis and underwent rapid drug desensitization with the goal to receive a continuous infusion of PCN G. The patient's hospital course was complicated by intermittent drug reactions consisting of tachycardia, rash, and dyspnea, followed by periods of being able to tolerate the infusion. After being able to tolerate the recommended dose of PCN infusion, the patient was discharged home to complete the course. However, he returned almost immediately after a recurrence of symptoms at home requiring the use of intramuscular epinephrine. Ultimately, the patient was transitioned to ceftriaxone and completed the infusion course as an inpatient because of continued intermittent recurrence of drug reaction symptoms.
Assuntos
Hipersensibilidade a Drogas , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Hipersensibilidade , Neurossífilis , Masculino , Humanos , Adulto , Hipersensibilidade a Drogas/complicações , Hipersensibilidade a Drogas/diagnóstico , Penicilinas/uso terapêutico , Neurossífilis/complicações , Neurossífilis/diagnóstico , Neurossífilis/tratamento farmacológico , Ceftriaxona/uso terapêutico , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/complicações , Hipersensibilidade/complicaçõesRESUMO
Histone deacetylases are important epigenetic regulators that have been reported to play essential roles in cancer stem cell functions and are promising therapeutic targets in many cancers including glioblastoma. However, the functionally relevant roles of specific histone deacetylases, in the maintenance of key self-renewal and growth characteristics of brain tumour stem cell (BTSC) sub-populations of glioblastoma, remain to be fully resolved. Here, using pharmacological inhibition and genetic loss and gain of function approaches, we identify HDAC2 as the most relevant histone deacetylase for re-organization of chromatin accessibility resulting in maintenance of BTSC growth and self-renewal properties. Furthermore, its specific interaction with the transforming growth factor-ß pathway related proteins, SMAD3 and SKI, is crucial for the maintenance of tumorigenic potential in BTSCs in vitro and in orthotopic xenograft models. Inhibition of HDAC2 activity and disruption of the coordinated mechanisms regulated by the HDAC2-SMAD3-SKI axis are thus promising therapeutic approaches for targeting BTSCs.
Assuntos
Neoplasias do Tronco Encefálico , Glioblastoma , Humanos , Glioblastoma/genética , Encéfalo , Histona Desacetilases/genética , Células-Tronco Neoplásicas , Epigênese Genética , Proteína Smad3/genética , Histona Desacetilase 2/genéticaRESUMO
Overlapping principles of embryonic and tumor biology have been described, with recent multi-omics campaigns uncovering shared molecular profiles between human pluripotent stem cells (hPSCs) and adult tumors. Here, using a chemical genomic approach, we provide biological evidence that early germ layer fate decisions of hPSCs reveal targets of human cancers. Single-cell deconstruction of hPSCs-defined subsets that share transcriptional patterns with transformed adult tissues. Chemical screening using a unique germ layer specification assay for hPSCs identified drugs that enriched for compounds that selectively suppressed the growth of patient-derived tumors corresponding exclusively to their germ layer origin. Transcriptional response of hPSCs to germ layer inducing drugs could be used to identify targets capable of regulating hPSC specification as well as inhibiting adult tumors. Our study demonstrates properties of adult tumors converge with hPSCs drug induced differentiation in a germ layer specific manner, thereby expanding our understanding of cancer stemness and pluripotency.
Assuntos
Neoplasias , Células-Tronco Pluripotentes , Humanos , Diferenciação Celular/fisiologia , Neoplasias/tratamento farmacológico , Neoplasias/genética , GenômicaRESUMO
Jackson et al. (2006) have reported that adult glial fibrillary acid protein (GFAP)-expressing neural stem cells (NSCs) also express platelet-derived growth factor (PDGF) receptor-α (PDGFRα), and that their stimulation by PDGF induced the formation of a glioma-like mass. Here, we reexamined the relationship between PDGFRα and GFAP expression within the three-dimensional organization of the adult periventricular area. Using four independent PDGFRα antibodies, we found that adult mouse GFAP-expressing NSCs and PDGFRα-expressing cells represent two distinct populations of neural precursors. Examination of the adult periventricular area in a mouse line that expresses nuclear-localized enhanced green fluorescent protein under the control of the PDGFRα promoter confirmed that GFAP-expressing NSCs do not express PDGFRα. Furthermore, PDGF-responsive neural precursors were found at least one cell layer subjacent to the ependymal layer, and were evenly distributed across the lateral ventricular wall, which contrasts with the reported patchy and often ependymal localization of adult GFAP-expressing NSCs. Adult human PDGFRα-expressing neural precursors were also found not to express GFAP. PDGF-responsive neural precursors, but not GFAP-expressing NSCs, responded to infusions of PDGF by generating glioma-like masses. Our results do not support the view that GFAP-expressing NSCs are the origin of glioma-like masses that form after intraventricular PDGF infusion.
Assuntos
Proteína Glial Fibrilar Ácida/metabolismo , Hipotálamo/metabolismo , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Adolescente , Adulto , Animais , Astrócitos/metabolismo , Humanos , Imuno-Histoquímica , Camundongos , Camundongos TransgênicosRESUMO
The formation of oligodendrocytes (oligodendrogenesis) and myelin is regulated by several neurotrophic factors. Strategies to increase the level of these trophic molecules may facilitate repair in demyelinating conditions, such as multiple sclerosis (MS). Because leukocytes are a source of neurotrophic factors, and as glatiramer acetate (GA) generates T helper 2 (Th2) lymphocytes that are not known to be harmful, we tested the hypothesis that GA regulates oligodendrogenesis and myelin formation. First, we generated GA-reactive Th2 cells and determined that they produced transcripts for neurotrophic factors, including insulin-like growth factor-1 (IGF-1). The conditioned medium from GA-reactive T cells elevated IGF-1 protein and promoted the formation of oligodendrocyte precursor cells (OPCs) from embryonic brain-derived forebrain cells in culture. We next subjected mice to lysolecithin-induced demyelination of the spinal cord. At 7 days after the insult, the number of OPCs in the demyelinated dorsal column was higher than that in uninjured controls, and was further increased by the daily s.c. injection with GA. Increased OPC generation by GA was associated temporally with the elevation of IGF-1 and brain-derived neurotrophic factor (BDNF) in the spinal cord. Finally, the resultant remyelination at 28 days was higher in mice treated with GA during the first 7 days of injury compared with vehicle controls. These results indicate that GA promotes oligodendrogenesis and remyelination through mechanisms that involve the elevation of growth factors conducive for repair.
Assuntos
Esclerose Múltipla/tratamento farmacológico , Bainha de Mielina/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Oligodendroglia/efeitos dos fármacos , Peptídeos/farmacologia , Animais , Meios de Cultivo Condicionados , Citocinas/metabolismo , Acetato de Glatiramer , Humanos , Imunossupressores/farmacologia , Técnicas In Vitro , Mediadores da Inflamação/metabolismo , Lisofosfatidilcolinas/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/imunologia , Esclerose Múltipla/patologia , Esclerose Múltipla/fisiopatologia , Bainha de Mielina/imunologia , Bainha de Mielina/fisiologia , Fatores de Crescimento Neural/biossíntese , Fatores de Crescimento Neural/genética , Neurogênese/fisiologia , Oligodendroglia/citologia , Oligodendroglia/imunologia , Oligodendroglia/fisiologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/patologia , Medula Espinal/fisiopatologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/fisiologiaRESUMO
Spinal cord injury (SCI) results in substantial oligodendrocyte death and subsequent demyelination leading to white-matter defects. Cell replacement strategies to promote remyelination are under intense investigation; however, the optimal cell for transplantation remains to be determined. We previously isolated a platelet-derived growth factor (PDGF)-responsive neural precursor (PRP) from the ventral forebrain of fetal mice that primarily generates oligodendrocytes, but also astrocytes and neurons. Importantly, human PRPs were found to possess a greater capacity for oligodendrogenesis than human epidermal growth factor- and/or fibroblast growth factor-responsive neural stem cells. Therefore, we tested the potential of PRPs isolated from green fluorescent protein (GFP)-expressing transgenic mice to remyelinate axons in the injured rat spinal cord. PRPs were transplanted 1 week after a moderate thoracic (T9) spinal cord contusion in adult male rats. After initial losses, PRP numbers remained stable from 2 weeks posttransplantation onward and those surviving cells integrated into host tissue. Approximately one-third of the surviving cells developed the typical branched phenotype of mature oligodendrocytes, expressing the marker APC-CC1. The close association of GFP cells with myelin basic protein as well as with Kv1.2 and Caspr in the paranodal and juxtaparanodal regions of nodes of Ranvier indicated that the transplanted cells successfully formed mature myelin sheaths. Transplantation of PRPs into dysmyelinated Shiverer mice confirmed the ability of PRP-derived cells to produce compact myelin sheaths with normal periodicity. These findings indicate that PRPs are a novel candidate for CNS myelin repair, although PRP-derived myelinating oligodendrocytes were insufficient to produce behavioral improvements in our model of SCI.