RESUMO
To study the estrogen regulated transcription of the uteroglobin (UG) gene, the founding member of the secretoglobin family widely expressed in many different mammalian species, we re-created functional estrogen response elements (EREs) in the UG gene promoter from a species where UG expression is not regulated by estrogens: the hamster Mesocricetus auratus (Ma), to ascertain if the lack of functional EREs is the real cause of its estrogen insensitivity. Functional EREs in the hamster promoter, including the consensus ERE (cERE), failed to respond to an appropriate estrogen stimulus compared with its estrogen regulated ortholog from the brown hare Lepus capensis (Lc). As the nucleotide sequence is the only difference between genetic constructs from these two species, we suspected that the UG promoter from the hamster probably contains cis-acting genetic elements that negatively impairs the estrogen-regulated transcription mediated by the functional ERE. Accordingly, we prepared chimeric DNA constructs which eventually allowed to identify a region located 29 base pairs (bp) downstream of the ERE as responsible for the lack of estrogen-responsiveness of the Ma-UG gene in the breast cancer cell line MCF-7. This region contains the sequence ACACCCC which has been identified as the core sequence of the Sp/ Krüppel-like factor (KLF) family of transcription factors. This finding is relevant, not only due to the observation on a novel mechanism that control estrogen-induced transcription, but also because it may encourage further investigation for better defining specific genes with an ERE that do not respond to estrogen signaling in MCF-7 cells, a cell line widely employed as an in vitro model in breast cancer research.
Assuntos
Neoplasias da Mama , Lebres , Cricetinae , Animais , Humanos , Feminino , Células MCF-7 , Uteroglobina/genética , Sequência de Bases , Estrogênios/farmacologia , Estrogênios/metabolismo , Neoplasias da Mama/genética , Lebres/metabolismo , Transcrição Gênica , Estradiol/farmacologiaRESUMO
RESUMO Objetivo: Avaliar a expressão sérica da proteína 1 relacionada à uteroglobulina na fase inicial após lesões por inalação de fumaça e sua associação com a gravidade da lesão por inalação em pacientes queimados. Métodos: A lesão por inalação de fumaça ou produtos químicos se associa com morbidade e mortalidade. As consequências da inalação resultam de uma resposta inflamatória. A proteína 1 relacionada à uteroglobulina é anti-inflamatória e pode melhorar a inflamação pulmonar. Nossa hipótese é que os níveis de proteína 1 relacionada à uteroglobulina podem refletir a gravidade da doença e predizer o desfecho em pacientes com lesão por inalação. Incluíram-se prospectivamente neste estudo 16 pacientes com diagnóstico de síndrome do desconforto respiratório agudo decorrente de lesão por inalação de fumaça. Em todos os pacientes, colheu-se amostra de plasma quando da admissão à unidade de terapia intensiva, para avaliar a gravidade da lesão por inalação dentro de 72 horas. Os níveis plasmáticos de proteína 1 relacionada à uteroglobulina foram determinados em duplicata por meio de ensaio de imunoabsorção ligado à enzima. Resultados: A média de idade foi de 23 ± 5 anos, e a distribuição da lesão por inalação foi: três em grau 1, quatro em grau 2 e nove em grau 3. O nível de proteína 1 relacionada à uteroglobulina foi relacionado ao grau de severidade (grau 1: 0,389 ± 0,053 unidade arbitrária versus grau 2: 0,474 ± 0,0423 unidade arbitrária versus grau 3: 0,580 ± 0,094 unidade arbitrária; p = 0,007). Conclusão: Os níveis plasmáticos de proteína 1 relacionada à uteroglobulina se associam com o grau da lesão pulmonar por inalação.
ABSTRACT Objective: To evaluate serum uteroglobin-related protein 1 expression early after smoke inhalation injuries and its association with the severity of inhalation injury in burned patients. Methods: Smoke or chemical inhalation injury is associated with morbidity and mortality. The consequences of inhalation result from an inflammatory response. Uteroglobin-related protein 1 is an anti-inflammatory protein and may improve lung inflammation. We hypothesized that uteroglobin-related protein 1 levels could reflect disease severity and predict outcome in patients with inhalation injury. Sixteen patients diagnosed with acute respiratory distress syndrome secondary to smoke inhalation injury were prospectively included in the study. Plasma was collected upon intensive care unit admission and within 24 hours of the inhalation injury. Bronchoscopies were carried out in all patients to assess the severity of inhalation injury within 72 hours. Uteroglobin-related protein 1 plasma levels were determined in duplicate with enzyme-linked immunosorbent assay. Results: The mean age was 23 ± 5 years, and the inhalation injury distribution was as follows: three of grade 1, four of grade 2, and nine of grade 3. The level of uteroglobin-related protein 1 was related to inhalation severity (grade 1: 0.389 ± 0.053 arbitrary units versus grade 2: 0.474 ± 0.0423 arbitrary units versus grade 3: 0.580 ± 0.094 arbitrary units; p = 0.007). Conclusion: Plasma levels of uteroglobin-related protein 1 are associated with the degree of lung inhalation injury.
Assuntos
Humanos , Adolescente , Adulto , Adulto Jovem , Síndrome do Desconforto Respiratório do Recém-Nascido , Queimaduras , Lesão por Inalação de Fumaça , Uteroglobina , Unidades de Terapia IntensivaRESUMO
To get further insights on the estrogen regulation of the uteroglobin (UG) gene, the 5'-flanking region of the UG gene from the brown hare (Lepus capensis) (Lc) was cloned and compared with those from two phylogenetically related species: the rabbit (Orictolagus cuniculus) (Oc) and the volcano rabbit (Romerolagus diazi) (Rd). The Lc-UG gene is very similar to those from rabbits (94%) and volcano rabbits (95%), and shares a number of genetic elements, including an estrogen response element (ERE). The estrogen-regulated transcription of a series of progressive 5'-deletion mutants of the Lc-UG gene, identified a functional ERE in the promoter region exhibiting the same orientation and relative position than that previously described in rabbits. The Lc-ERE is identical to the Oc-ERE, but different from both the Rd-ERE and the consensus ERE (c-ERE) by one nucleotide. We also detected important species-specific differences in the estrogen-regulated transcription of the UG gene. A luciferase reporter driven by 333 base pairs (bp) of the Lc-UG promoter elicited a higher response to estradiol than its related counterparts when expressed in estrogen-sensitive MCF-7 cells. Several ERE-like motifs which failed to act as functional EREs were also identified; one of them exhibited two mismatches in its palindromic sequence, a characteristic exhibited in many other natural occurring EREs, including the Rd-ERE.