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Background: Approximately 20% of adults in Vietnam have hypertension, and management of this chronic condition remains challenging. This study aimed to assess the effectiveness of a multicomponent intervention in reducing blood pressure (BP) in adults with uncontrolled hypertension. Methods: This cluster randomised controlled trial was conducted in sixteen communities (8 intervention and 8 comparison) in a rural setting in Vietnam (2017-2022). Consenting adults (aged ≥ 18 years) with uncontrolled hypertension were enrolled. Sixteen communities were equally randomised to an intervention or comparison group stratified by district. Consenting adults were assigned to study groups by community. The comparison arm received training sessions about hypertension prevention and management for health workers, and patient education materials. The intervention arm received training sessions about hypertension prevention and management for health workers, and patient education materials and three enhancement components including a storytelling intervention, home BP self-monitoring, and expanded community health worker services. The primary outcome was the difference in changes in patient's levels of systolic BP between the study groups over a 12-month follow-up period. Patients and outcome assessors were masked. Findings: A total of 671 patients (340: intervention, 331: comparison) were enrolled in the trial. The mean age was 66 years and 45% were men. At the 12-month follow-up, the mean systolic BP declined by 18.4 mmHg in the intervention group and 3.7 mmHg in the comparison group (differential decline of 14.7 mmHg [95% CI: 11.8-17.6]). The intervention group also achieved better BP control and medication adherence than the comparison group. There were no serious adverse events related to study participation. Interpretation: The results of this trial demonstrate that a multicomponent intervention can effectively reduce elevated BP in individuals with uncontrolled hypertension in Vietnam. Trial registration: This trial was registered at ClinicalTrials.gov, NCT03590691. Funding: National Heart, Lung, and Blood Institute.
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Cutaneous collagenous vasculopathy (CCV) is a rare idiopathic dermal microangiopathy. Clinically, it presents as diffuse cutaneous telangiectasias that are indistinguishable from other benign vascular entities, thereby posing a diagnostic challenge. We present a case of CCV successfully treated with pulsed dye laser (PDL). A 27-year-old male presented with generalized erythematous macules, diagnosed as CCV via histopathology. After a successful test spot, PDL treatment resulted in significant improvement. The pathogenesis of CCV involves altered dermal microvasculature and veil cell activation. Epidemiologically, it primarily affects Caucasians, most often in the middle-aged adult population. A negative family history of similar lesions can help narrow down the differential diagnosis. Diagnosis requires biopsy, with histopathological examination demonstrating vessel ectasia and collagenous vessel wall thickening. Given its rarity, CCV presents diagnostic and management challenges though PDL emerges as a promising treatment modality for this condition.
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PURPOSE: Gut microbiota play an important role in human health, including cancer. Cancer and its treatment, in turn, may alter the gut microbiome. To understand this complex relationship, we profiled the gut microbiome of 356 Vietnamese patients with breast cancer. MATERIALS AND METHODS: Stool samples were collected before chemotherapy, with 162 pre- and 194 postsurgery. The gut microbiome was measured by shotgun metagenomic sequencing. Associations of gut microbial diversity, taxa abundance, and gut microbiome health index (GMHI) with sociodemographic, clinical factors, and tumor characteristics were evaluated. RESULTS: Postsurgery samples were associated with significantly lower α- and ß-diversities (P < .001) and showed significant differences in the abundance of 15% of 2,864 investigated taxa (false discovery rate [FDR] <0.1) compared with presurgery samples. An unhealthy gut microbiome was prevalent among patients with breast cancer, with a mean GMHI of -0.79 and -2.81 in pre- and postsurgery stool samples, respectively. In an analysis of 162 presurgery stool samples, diagnosis delay was significantly associated with lower α-diversity, variation in ß-diversity, an increased abundance of species Enorma massiliensis, and a decreased abundance of Faecalicoccus pleomorphus. High intake of fiber was significantly associated with lower α-diversity and a higher abundance of species belonging to Bifidobacterium, Prevotella, and Bacteroides gena (FDR < 0.1). We did not find that cancer stage and subtype, menopausal status, comorbidity, antibiotic use during 3 months before stool collection, or physical activity was significantly associated with α- and ß-diversities or GMHI although a few significant differences were observed in taxa abundance. CONCLUSION: Our study revealed that diagnosis delay, high fiber intake, and breast cancer surgery, which is always followed by antibiotic prophylaxis in Vietnam, led to a less diverse and unhealthy gut microbiome among patients with breast cancer.
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Neoplasias da Mama , Microbioma Gastrointestinal , Humanos , Feminino , Vietnã/epidemiologia , Fezes/microbiologia , MetagenomaRESUMO
Noniatrogenically acquired foreign bodies in the nipple-areola complex or breast skin are rare and can have variable imaging features, depending on the nature of the foreign material. We present the case of a 41-year-old female who had numerous apparent round and punctate calcifications in the right periareolar breast, predominantly within the skin. The biopsy showed multiple glass shards on a background of scar tissue. Further discussion with the patient confirmed that the glass shards were acquired during a motor vehicle accident several years earlier. We also review the types of foreign body material observed in the breast, the imaging appearance of glass foreign bodies in soft tissue, and methods of removal.
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Neurodevelopmental psychopathology seeks to understand higher-order emotion regulation circuitry to develop new therapies for adolescents with depression. Depressed (N = 34) and healthy youth (N = 19) completed neurofeedback (NF) training and exhibited increased bilateral amygdala and hippocampus activity in the region of interest (ROI) analyses by recalling positive autobiographical memories. We tested factors supportive of the engagement of emotion regulation's neural areas during NF (i.e., parental support, medication, and gender effects upon anterior cingulate cortex (ACC) engagement). Whole-brain analyses yielded effects of NF vs. control condition and effects of diagnosis. Youth showed higher amygdala and hippocampus (AMYHIPPO) activity during the NF vs. control condition, particularly in the left hippocampus. ACC's activity was also higher during NF vs. control. Higher average ACC activity was linked to better parental support, absent depression, female gender, and absent medication. Control youth showed higher average AMYHIPPO and ACC activity throughout the task and a faster decline in activity vs. depressed youths. Whole-brain level analyses showed higher activity in the frontotemporal network during the NF vs. control conditions, suggesting targeting their connectivity in future neurofeedback trials.
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Recent advancements in stem cell technology open a new door for patients suffering from diseases and disorders that have yet to be treated. Stem cell-based therapy, including human pluripotent stem cells (hPSCs) and multipotent mesenchymal stem cells (MSCs), has recently emerged as a key player in regenerative medicine. hPSCs are defined as self-renewable cell types conferring the ability to differentiate into various cellular phenotypes of the human body, including three germ layers. MSCs are multipotent progenitor cells possessing self-renewal ability (limited in vitro) and differentiation potential into mesenchymal lineages, according to the International Society for Cell and Gene Therapy (ISCT). This review provides an update on recent clinical applications using either hPSCs or MSCs derived from bone marrow (BM), adipose tissue (AT), or the umbilical cord (UC) for the treatment of human diseases, including neurological disorders, pulmonary dysfunctions, metabolic/endocrine-related diseases, reproductive disorders, skin burns, and cardiovascular conditions. Moreover, we discuss our own clinical trial experiences on targeted therapies using MSCs in a clinical setting, and we propose and discuss the MSC tissue origin concept and how MSC origin may contribute to the role of MSCs in downstream applications, with the ultimate objective of facilitating translational research in regenerative medicine into clinical applications. The mechanisms discussed here support the proposed hypothesis that BM-MSCs are potentially good candidates for brain and spinal cord injury treatment, AT-MSCs are potentially good candidates for reproductive disorder treatment and skin regeneration, and UC-MSCs are potentially good candidates for pulmonary disease and acute respiratory distress syndrome treatment.
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Células-Tronco Mesenquimais , Tecido Adiposo , Diferenciação Celular/genética , Humanos , Medicina Regenerativa , Cordão UmbilicalRESUMO
Pharmacies represent a key health system entry point for people with TB in Viet Nam, but high fragmentation hinders their broader engagement. Professional networking apps may be able to facilitate pharmacy engagement for systematic TB screening and referral. Between September and December 2019, we piloted the use of a social networking app, SwipeRx, to recruit pharmacists for a TB referral scheme across four districts of Ho Chi Minh City, Viet Nam. We measured chest X-ray (CXR) referrals and TB detection yields at participating pharmacies and fielded 100 acceptability surveys, divided into pharmacists who did and did not make a CXR referral. We then fitted mixed-effect odds proportional models to explore acceptability factors that were associated with making a CXR referral. 1,816 push notifications were sent to pharmacists via the SwipeRx app and 78 indicated their interest in participating; however, only one was within the pilot's intervention area. Additional in-person outreach resulted in the recruitment of 146 pharmacists, with 54 (37.0%) making at least one CXR referral. A total of 182 pharmacy customers were referred, resulting in a total of 64 (35.2%) CXR screens and seven people being diagnosed with TB. Compared to pharmacists who did not make any CXR referrals, pharmacists making at least one CXR referral understood the pilot's objectives more clearly (aOR = 2.6, 95% CI: 1.2-5.8) and they believed that TB screening increased customer trust (aOR = 2.7, 95% CI: 1.2-5.8), benefited their business (aOR = 2.8, 95% CI: 1.3-6.2) and constituted a competitive advantage (aOR = 4.4, 95% CI: 1.9-9.9). They were also more confident in using mHealth apps (aOR = 3.1, 95 CI%: 1.4-6.8). Pharmacies can play an important role in early and increased TB case finding. It is critical to highlight the value proposition of TB referral schemes to their business during recruitment. Digital networking platforms, such as SwipeRx, can facilitate referrals for TB screening by pharmacists, but their ability to identify and recruit pharmacists requires optimization, particularly when targeting specific segments of a nation-wide digital network.
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BACKGROUND: The COVID-19 pandemic has had a profound worldwide impact. Vietnam, a lower middle-income country with limited resources, has successfully slowed this pandemic. The objectives of this report are to explore the impact of the COVID-19 pandemic on the research activities of an ongoing hypertension trial using a storytelling intervention in Vietnam. METHODS: Data were collected in a mixed-methods study among 86 patients and 10 health care workers participating in a clinical trial designed to improve hypertension control. Several questions related to the impact of COVID-19 on patient's daily activities and adherence to the study interventions were included in the follow-up visits. A focus group discussion was conducted among health care workers to discuss the impact of COVID-19 on research related activities. RESULTS: Fewer patients in the intervention group reported that they faced difficulties in adhering to prescribed study interventions, wanted to receive a call from a dedicated hotline, or have a visit from a community health worker as compared with those in the comparison group. Most study patients are willing to participate in future health research studies. When asked about the potential use of mobile phones in health research studies, fewer patients in the intervention group felt comfortable using a mobile phone for the delivery of intervention and interviews compared with those in the comparison condition. Community health workers shared that they visited patient's homes more often than previously due to the pandemic and health care workers had to perform more virus containment activities without a corresponding increase in ancillary staff. CONCLUSIONS: Both patients and health care workers in Vietnam faced difficulties in adhering to recommended trial interventions and procedures. Multiple approaches for intervention delivery and data collection are needed to overcome these difficulties during future health crises and enhance the implementation of future research studies. TRIAL REGISTRATION: ClinicalTrials.gov. Registration number: https://clinicaltrials.gov/ct2/show/NCT03590691 (registration date July 17, 2018).
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COVID-19/epidemiologia , Serviços de Laboratório Clínico/normas , Ensaios Clínicos como Assunto , Pessoal de Laboratório Médico/psicologia , Pacientes/psicologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Serviços de Laboratório Clínico/estatística & dados numéricos , Feminino , Humanos , Hipertensão/epidemiologia , Masculino , Pessoa de Meia-Idade , Cooperação do Paciente , VietnãRESUMO
BACKGROUND: Vietnam has been experiencing an epidemiologic transition to that of a lower-middle income country with an increasing prevalence of non-communicable diseases. The key risk factors for cardiovascular disease (CVD) are either on the rise or at alarming levels in Vietnam, particularly hypertension (HTN). Inasmuch, the burden of CVD will continue to increase in the Vietnamese population unless effective prevention and control measures are put in place. The objectives of the proposed project are to evaluate the implementation and effectiveness of two multi-faceted community and clinic-based strategies on the control of elevated blood pressure (BP) among adults in Vietnam via a cluster randomized trial design. METHODS: Sixteen communities will be randomized to either an intervention (8 communities) or a comparison group (8 communities). Eligible and consenting adult study participants with HTN (n = 680) will be assigned to intervention/comparison status based on the community in which they reside. Both comparison and intervention groups will receive a multi-level intervention modeled after the Vietnam National Hypertension Program including education and practice change modules for health care providers, accessible reading materials for patients, and a multi-media community awareness program. In addition, the intervention group only will receive three carefully selected enhancements integrated into routine clinical care: (1) expanded community health worker services, (2) home BP self-monitoring, and (3) a "storytelling intervention," which consists of interactive, literacy-appropriate, and culturally sensitive multi-media storytelling modules for motivating behavior change through the power of patients speaking in their own voices. The storytelling intervention will be delivered by DVDs with serial installments at baseline and at 3, 6, and 9 months after trial enrollment. Changes in BP will be assessed in both groups at several follow-up time points. Implementation outcomes will be assessed as well. DISCUSSION: Results from this full-scale trial will provide health policymakers with practical evidence on how to combat a key risk factor for CVD using a feasible, sustainable, and cost-effective intervention that could be used as a national program for controlling HTN in Vietnam. TRIAL REGISTRATION: ClinicalTrials.gov NCT03590691 . Registered on July 17, 2018. Protocol version: 6. Date: August 15, 2019.
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Doenças Cardiovasculares , Hipertensão , Adulto , Agentes Comunitários de Saúde , Análise Custo-Benefício , Humanos , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Vietnã/epidemiologiaAssuntos
Glucocorticoides/uso terapêutico , Antígenos HLA-B/genética , Infliximab/uso terapêutico , Metazolamida/efeitos adversos , Síndrome de Stevens-Johnson/tratamento farmacológico , Síndrome de Stevens-Johnson/etiologia , Adulto , Povo Asiático , China , Quimioterapia Combinada , Glaucoma/diagnóstico , Glaucoma/tratamento farmacológico , Humanos , Masculino , Metazolamida/uso terapêutico , Prognóstico , Índice de Gravidade de Doença , Síndrome de Stevens-Johnson/genética , Resultado do TratamentoRESUMO
The Werner syndrome (WS) is a prototypic adult Mendelian progeroid syndrome in which signs of premature aging are associated with genomic instability and an elevated risk of cancer. The WRN RECQ helicase protein binds and unwinds G-quadruplex (G4) DNA substrates in vitro, and we identified significant enrichment in G4 sequence motifs at the transcription start site and 5' ends of first introns (false discovery rate < 0.001) of genes down-regulated in WS patient fibroblasts. This finding provides strong evidence that WRN binds G4 DNA structures at many chromosomal sites to modulate gene expression. WRN appears to bind a distinct subpopulation of G4 motifs in human cells, when compared with the related Bloom syndrome RECQ helicase protein. Functional annotation of the genes and miRNAs altered in WS provided new insight into WS disease pathogenesis. WS patient fibroblasts displayed altered expression of multiple, mechanistically distinct, senescence-associated gene expression programs, with altered expression of disease-associated miRNAs, and dysregulation of canonical pathways that regulate cell signaling, genome stability and tumorigenesis. WS fibroblasts also displayed a highly statistically significant and distinct gene expression signature, with coordinate overexpression of nearly all of the cytoplasmic tRNA synthetases and associated ARS-interacting multifunctional protein genes. The 'non-canonical' functions of many of these upregulated tRNA charging proteins may together promote WS disease pathogenesis. Our results identify the human WRN RECQ protein as a G4 helicase that modulates gene expression in G4-dependent fashion at many chromosomal sites and provide several new and unexpected mechanistic insights into WS disease pathogenesis.
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Proteínas de Ligação a DNA/genética , Instabilidade Genômica/genética , Neoplasias/genética , RecQ Helicases/genética , Síndrome de Werner/genética , Carcinogênese/genética , Proteínas de Ligação a DNA/metabolismo , Fibroblastos , Quadruplex G , Regulação da Expressão Gênica , Genoma Humano , Humanos , MicroRNAs , Neoplasias/patologia , Motivos de Nucleotídeos , RecQ Helicases/metabolismoRESUMO
BACKGROUND: Histiocytoid Sweet's syndrome was originally described as cutaneous lesions of Sweet's syndrome where the infiltrate is mostly composed of histiocytoid mononuclear cells. The putative cell has been interpreted as an immature neutrophil based on the intense expression of myeloperoxidase. METHODS: To better understand the nature of the infiltrate and potential mechanisms leading to this distinct form of cutaneous inflammatory cell influx, thirteen cases of histiocytoid Sweet's syndrome, encountered in the routine and consult practice of one of the authors, were studied. The clinical features and microscopic findings are summarized. RESULTS: The study comprised eight men and five women aged from 23 to 80. There was a significant association with underlying myeloproliferative disease. In particular, five patients had underlying myelodysplastic syndrome. One patient had unspecified chronic myeloproliferative disorder and another had AML. Two cases were triggered by drug therapy (Cox-2 inhibitors). One patient had familial Mediterranean fever. The eruption was asymptomatic and an aggressive clinical course was not observed in most cases. Skin biopsies were composed of striking angiocentric and intersititial mononuclear cell infiltrates, often accentuated in the deeper dermis and subcutaneous fat. There was marked leukocytoclasia. Neutrophils were sparce or absent. These cells were strongly positive for CD163 and either expressed CD16 or myeloperoxidase. Variable positivity for myeloid dendritic cell markers including CD11c, BDCA-3, TCL1 oncogene, MXA and CD123 was observed. CONCLUSION: The histiocytoid cells of histiocytoid Sweet's syndrome define a novel subset of activated monocytes. This variant of Sweet's syndrome has a significant association with underlying myeloproliferative disease.
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Histiócitos/química , Síndromes Mielodisplásicas/complicações , Transtornos Mieloproliferativos/complicações , Síndrome de Sweet/complicações , Síndrome de Sweet/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos CD/análise , Antígenos de Diferenciação Mielomonocítica/análise , Antígenos de Superfície/análise , Antígeno CD11c , Células Dendríticas/química , Células Dendríticas/patologia , Feminino , Proteínas Ligadas por GPI/análise , Histiócitos/patologia , Humanos , Subunidade alfa de Receptor de Interleucina-3/análise , Leucemia Mieloide Aguda/complicações , Leucócitos Mononucleares , Masculino , Pessoa de Meia-Idade , Proteínas de Resistência a Myxovirus/análise , Neutrófilos , Peroxidase/análise , Fenótipo , Proteínas Proto-Oncogênicas/análise , Receptores de Superfície Celular/análise , Receptores de IgG/análise , Trombomodulina , Adulto JovemRESUMO
The microRNA-34 family (miR-34a, -34b and -34c) have been reported to be tumor suppressor microRNAs (miRNAs) that are regulated by the TP53 and DNA hypermethylation. However, the expression, regulation, and prognostic value of the miR-34 family have not been systematically studied in colon cancer. To elucidate the roles of miR-34 family in colon carcinogenesis, miR-34a/b/c were measured in tumors and adjacent noncancerous tissues from 159 American and 113 Chinese colon cancer patients using quantitative RT-PCR, and we examined associations between miR-34a/b/c expression with TNM staging, cancer-specific mortality, TP53 mutation status and Affymetrix microarray data. All miR-34 family members were significantly increased in colon tumors, counter to the proposed tumor suppressor role for these miRNAs. Increased miR-34b/c were observed in more advanced tumors in two independent cohorts and increased expression of miR-34b/c was associated with poor cancer-specific mortality. While the expression of miR-34 family was not associated with TP53 mutation status, TP53 transcriptional activity was associated with miR-34a/b/c expression that is consistent with the proposed regulation of miR-34a/b/c by TP53. To examine where the miR-34 family is expressed, the expression of miR-34 family was compared between epitheliums and stromal tissues using laser microdissection technique. The expression of miR-34b/c was increased significantly in stromal tissues, especially in cancer stroma, compared with epithelial tissue. In conclusion, increased miR-34b/c predominantly expressed in stromal tissues is associated with poor prognosis in colon cancer. MiR-34 may contribute to cancer-stromal interaction associated with colon cancer progression.
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Neoplasias do Colo/diagnóstico , Neoplasias do Colo/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Colo/patologia , Feminino , Humanos , Mucosa Intestinal/metabolismo , Masculino , Pessoa de Meia-Idade , Mutação , Prognóstico , Células Estromais/metabolismo , Proteína Supressora de Tumor p53/genética , Regulação para CimaRESUMO
Human cells utilize a variety of complex DNA repair mechanisms in order to combat constant mutagenic and cytotoxic threats from both exogenous and endogenous sources. The RecQ family of DNA helicases, which includes Bloom helicase (BLM), plays an important function in DNA repair by unwinding complementary strands of duplex DNA as well as atypical DNA structures such as Holliday junctions. Mutations of the BLM gene can result in Bloom syndrome, an autosomal recessive disorder associated with cancer predisposition. BLM-deficient cells exhibit increased sensitivity to DNA damaging agents indicating that a selective BLM inhibitor could be useful in potentiating the anticancer activity of these agents. In this work, we describe the medicinal chemistry optimization of the hit molecule following a quantitative high-throughput screen of >355,000 compounds. These efforts lead to the identification of ML216 and related analogs, which possess potent BLM inhibition and exhibit selectivity over related helicases. Moreover, these compounds demonstrated cellular activity by inducing sister chromatid exchanges, a hallmark of Bloom syndrome.
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Aminas/química , Inibidores Enzimáticos/síntese química , Compostos de Fenilureia/síntese química , RecQ Helicases/antagonistas & inibidores , Tiadiazóis/química , Aminas/síntese química , Aminas/farmacologia , Células CACO-2 , Permeabilidade da Membrana Celular/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Compostos de Fenilureia/química , Compostos de Fenilureia/farmacologia , RecQ Helicases/metabolismo , Relação Estrutura-Atividade , Tiadiazóis/síntese química , Tiadiazóis/farmacologiaRESUMO
microRNA (miRNA) are small non-coding RNA targeting mRNAs leading to their instability and diminished translation. Altered expression of miRNA is associated with cancer. Inflammation and nitric oxide modulates the development of lymphomas in p53 knockout mice and there exists a negative feedback loop between p53 and NOS2. Using a genetic strategy, we tested the hypothesis that inflammation-induced oxidative and nitrosative stress modulates miRNA expression in mouse model deficient in either p53 or NOS2. Mice treated with Corynebacterium parvum (C. parvum), to induce inflammation, clearly separated from controls by their miRNA profiles in wild-type, p53- and NOS2-knockout genetic backgrounds. C. parvum-induced inflammation significantly (p < 0.005) increased miR-21, miR-29b and miR-34a/b/c and decreased (p < 0.005) mir-29c and mir-181a/c expression in the spleen of C57BL mice. However, p53-knockout C57BL mice did not show a significant increase in the mir-34b/c or a decrease in mir-29c expression following C. parvum-induced inflammation. Expression of mir-21, mir-29b and mir-181a was independent of p53-status. NOS2-knockout C57BL mice showed a significant increase in miR-21 and miR-34a/b/c and decrease in miR-181a similar to the wild-type (WT) mice following C. parvum-induced inflammation. However, in contrast to the WT mice, miR-29b/c expression was not affected following C. parvum-induced inflammation in NOS2 knockout mice. N-acetyl cysteine, an anti-oxidant, reduced the expression of miR-21 and miR-29b in C. parvum-treated WT mice (p < 0.005) as compared with control C. parvum-treated mice. These data are consistent with the hypothesis that inflammation modulates miRNA expression in vivo and the alteration in specific miRNA under an inflammatory microenvironment, can be influenced by p53 (miR-34b/c) and NO(â¢) (29b/c).
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Inflamação/genética , MicroRNAs/metabolismo , Óxido Nítrico/metabolismo , Estresse Oxidativo , Proteína Supressora de Tumor p53/metabolismo , Animais , Linfoma/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/genética , Óxido Nítrico Sintase Tipo II/deficiência , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Nitrosação , Propionibacterium acnes/imunologia , Proteína Supressora de Tumor p53/deficiência , Proteína Supressora de Tumor p53/genéticaRESUMO
The finite proliferative potential of normal human cells leads to replicative cellular senescence, which is a critical barrier to tumour progression in vivo. We show that the human p53 isoforms Delta133p53 and p53beta function in an endogenous regulatory mechanism for p53-mediated replicative senescence. Induced p53beta and diminished Delta133p53 were associated with replicative senescence, but not oncogene-induced senescence, in normal human fibroblasts. The replicatively senescent fibroblasts also expressed increased levels of miR-34a, a p53-induced microRNA, the antisense inhibition of which delayed the onset of replicative senescence. The siRNA (short interfering RNA)-mediated knockdown of endogenous Delta133p53 induced cellular senescence, which was attributed to the regulation of p21(WAF1) and other p53 transcriptional target genes. In overexpression experiments, whereas p53beta cooperated with full-length p53 to accelerate cellular senescence, Delta133p53 repressed miR-34a expression and extended the cellular replicative lifespan, providing a functional connection of this microRNA to the p53 isoform-mediated regulation of senescence. The senescence-associated signature of p53 isoform expression (that is, elevated p53beta and reduced Delta133p53) was observed in vivo in colon adenomas with senescent phenotypes. The increased Delta133p53 and decreased p53beta isoform expression found in colon carcinoma may signal an escape from the senescence barrier during the progression from adenoma to carcinoma.
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Senescência Celular , Proteína Supressora de Tumor p53/metabolismo , Linhagem Celular Tumoral , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , MicroRNAs/metabolismo , Mutação/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteína Supressora de Tumor p53/genéticaRESUMO
Since the molecular cloning of the vzg-1/Edg-2/LPA1 gene, studies have attempted to characterize LPA1 receptor functionality into a single categorical role, different from the other Edg-family LPA receptors. The desire to categorize LPA1 function has highlighted its complexity and demonstrated that the LPA1 receptor does not have one absolute function throughout every system. The central nervous system is highly enriched in the LPA1 receptor, suggesting an integral role in neuronal processes. Metastatic and invasive breast cancer also appears to have LPA-mediated LPA1 receptor functions that enhance phenotypes associated with tumorigenesis. LPA1 possesses a number of motifs conserved among G protein-coupled receptors (GPCRs): a DRY-like motif, a PDZ domain, Ser/Thr predicted sites of phosphorylation, a di-leucine motif, double cysteines in the tail and conserved residues that stabilize structure and determine ligand binding. The third intracellular loop of the LPA1 receptor may be the crux of receptor signaling and attenuation with phosphorylation of Thr-236 potentially a key determinant of basal LPA1 signaling. Mutagenesis data supports the notion that Thr-236 regulates this process since mutating Thr-236 to Ala-236 increased basal and LPA-mediated serum response factor (SRF) signaling activity and Lys-236 further increased this basal signaling. Here we describe progress on defining the major functions of the LPA1 receptor, discuss a context dependent dualistic role as both a negative regulator in cancer and a proto-oncogene, outline its structural components at the molecular amino acid level and present mutagenesis data on the third intracellular loop of the receptor.