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BACKGROUND: Breast cancer (BC) is known to be the most common malignancy in females whereas colorectal cancer (CRC) incidence also higher in both genders in Sri Lanka. TP53 is an important tumour suppressor gene and its somatic mutations are reported in approximately 27% of BC and 43% of CRC cases. Analysis of TP53 gene variants not only provides clues for the aetiology of the tumour formation, but also has an impact on treatment efficacy. The current study was conducted to investigate the pattern of TP53 variants in patients with BC and CRC from Sri Lanka. METHODS: 30 patients with BC, 21 patients with CRC and an equal number of healthy controls were screened for mutational status of TP53 by polymerase chain reaction (PCR) followed by direct sequencing. In addition, a subset of these samples were analysed for the protein expression of p53 and comparison made with the mutational status of TP53. We also analysed the protein expression of p21 and MDM2 as potential indicators of p53 functional status and compared it with the protein expression of p53. Additionally, hotspot codons of the KRAS, BRAF and PIK3CA genes were also analysed in a subset of CRC patients. RESULTS: Twenty seven sequence variants, including several novel variants in the TP53 gene were found. Nine BC and seven CRC tumour samples carried pathogenic TP53 variants. Pathogenic point missense variants were associated with strong and diffuse positive staining for p53 by immunohistochemistry (IHC), whereas, wild type TP53 showed complete absence of positive IHC staining or rare positive cells, regardless of the type of cancer. There was no direct correlation between p21 or MDM2 expression and p53 expression in either BCs or CRCs. Four of the CRC patients had pathogenic hotspot variants in KRAS; three of them were on codon 12 and one was on codon 61. CONCLUSION: The prevalence of pathogenic somatic TP53 variants was 31 and 33.33% in the studied BC and CRC cohorts respectively. All of them were located in exons 5-8 and the pathogenic missense variants were associated with strong immuno-positive staining for p53.
Assuntos
Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/genética , Regulação Neoplásica da Expressão Gênica , Variação Genética , Proteína Supressora de Tumor p53/genética , Adulto , Idoso , Alelos , Sequência de Aminoácidos , Biomarcadores Tumorais , Estudos de Casos e Controles , Bases de Dados Factuais , Feminino , Expressão Gênica , Genótipo , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Vigilância em Saúde Pública , Sri Lanka/epidemiologia , Relação Estrutura-Atividade , Proteína Supressora de Tumor p53/químicaRESUMO
Leptin and visfatin are implicated in breast cancer risk but studies accounting for bioavailability of leptin are sparse. Reports on the association of leptin gene (LEP) and leptin receptor gene (LEPR) polymorphisms with breast cancer are also inconsistent. Only a very few studies have examined biochemical and genetic variables concomitantly in the same cohort. A matched pairs study was carried out to ascertain whether plasma leptin, soluble leptin receptor, free leptin index (leptin/soluble leptin receptor), serum visfatin and selected LEP and LEPR polymorphisms are risk factors for sporadic breast cancer. Newly diagnosed sporadic breast cancer patients (N=80) were matched for age, body mass index (BMI) and menopausal status with healthy controls. Plasma leptin, soluble leptin receptor and serum visfatin were measured by enzyme-immunoassay. LEP -2548 A/G and LEPR K109R, LEPR Q223R polymorphisms were determined by genotyping. Leptin (p=0.0234), leptin/BMI (p=0.0468), free leptin index (p<0.0001) and visfatin (p=0.0002) were significantly higher and soluble leptin receptor (p<0.0001) was significantly lower in patients. LEPR gene K109R A/G polymorphism increased breast cancer risk (odds ratio: 4.125). Multivariate analysis confirmed that leptin, soluble leptin receptor, free leptin index and G109 (R109) allele of the LEPR gene K109R polymorphism are risk factors for breast cancer. When stratified by menopausal status free leptin index and soluble leptin receptor remained as risk factors irrespective of menopausal status while LEPR gene K109R A/G polymorphism remained as a risk factor only in the postmenopausal group.
Assuntos
Neoplasias da Mama/genética , Citocinas/sangue , Leptina/sangue , Leptina/genética , Nicotinamida Fosforribosiltransferase/sangue , Receptores para Leptina/sangue , Receptores para Leptina/genética , Adulto , Idoso , Neoplasias da Mama/sangue , Estudos de Casos e Controles , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Humanos , Menopausa/sangue , Menopausa/genética , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Adulto JovemRESUMO
Understanding the nature of interactions between engineered nanomaterials and plants is crucial in comprehending the impact of nanotechnology on the environment and agriculture with a focus on toxicity concerns, plant disease treatment, and genetic engineering. To date, little progress has been made in studying nanoparticle-plant interactions at single nanoparticle and genetic levels. Here, we introduce an advanced platform integrating genetic, Raman, photothermal, and photoacoustic methods. Using this approach, we discovered that multiwall carbon nanotubes induce previously unknown changes in gene expression in tomato leaves and roots, particularly, up-regulation of the stress-related genes, including those induced by pathogens and the water-channel LeAqp2 gene. A nano-bubble amplified photothermal/photoacoustic imaging, spectroscopy, and burning technique demonstrated the detection of multiwall carbon nanotubes in roots, leaves, and fruits down to the single nanoparticle and cell level. Thus, our integrated platform allows the study of nanoparticles' impact on plants with higher sensitivity and specificity, compared to existing assays.
Assuntos
Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Solanum lycopersicum/metabolismo , Aquaporina 2/metabolismo , Citometria de Varredura a Laser , Lasers , Análise em Microsséries , Reação em Cadeia da Polimerase , Análise Espectral/métodosRESUMO
Breast cancer is the commonest malignancy in women and the majority occurs sporadically with no hereditary predisposition. However, sporadic breast cancer has been studied less intensively than the hereditary form and to date hardly any predictive biomarkers exist for the former. Furthermore, although mitochondrial DNA variants have been reported to be associated with breast cancer, findings have been inconsistent across populations. Thus we carried out a case control study on sporadic breast cancer patients and healthy controls of Sinhalese ethnicity (N = 60 matched pairs) in order to characterize coding region variants associated with the disease and to identify any potential biomarkers. Mitochondrial genome was fully sequenced in 30 pairs and selected regions were sequenced in the remaining 30 pairs. Several in-silico tools were used to assess functional significance of the variants observed. A number of variants were identified among the patients and the controls. Missense variants identified were either polymorphisms or rare variants. Their prevalence did not significantly differ between patients and the healthy controls (matched for age, body mass index and menopausal status). MT-CYB, MT-ATP6 and MT-ND2 genes showed a higher mutation rate. A higher proportion of pre-menopausal patients carried missense and pathogenic variants. Unique combinations of missense variants were seen within genes and these occurred mostly in MT-ATP6 and MT-CYB genes. Such unique combinations that occurred exclusively among the patients were common in obese patients. Mitochondrial DNA variants may have a role in breast carcinogenesis in obesity and pre-menopause. Molecular dynamic simulations suggested the mutants, G78S in MT-CO3 gene and T146A in MT-ATP6 gene are likely to be more stable than their wild type counterparts.
Assuntos
Neoplasias da Mama , Genoma Mitocondrial , Humanos , Feminino , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Sri Lanka/epidemiologia , Estudos de Casos e Controles , Proteômica , DNA Mitocondrial/genética , BiomarcadoresRESUMO
BACKGROUND: Oral squamous cell cancer (OSCC) is one of the commonest cancers in Sri Lanka. OBJECTIVES: This study aimed to determine the use of alcohol, its duration and consuming pattern in relation to the risk of developing OSCC in patients attending the National Cancer Institute of Sri Lanka. METHODS: A case-control study was carried out on 105 patients with a histologically confirmed primary OSCC and 210 age-sex matched controls. Information on alcohol consumption was obtained via an interviewer-administered questionnaire. RESULTS: Participants who had consumed alcohol at some point in their life had a 3.8-fold risk of developing OSCC (p=0.000). Current consumers had a higher risk compared to who have consumed previously. Former consumers had a lower risk of developing OSCC compared to current consumers. Individuals who had consumed alcohol for more than 20 years had a greater risk [Odds ratio (OR)=4.69] of developing OSCC compared to those who had consumed alcohol for less than ten years (OR=3.25). Those who consumed the locally-made illicit liquor (Kasippu) had the greatest risk (OR=8.45; p<0.05) of developing OSCC when considering the type of alcohol consumed. CONCLUSIONS: Alcohol consumption is a risk factor for OSCC. The OSCC risk increased with longer duration of alcohol use, the consumption of locally-made illicit liquor and current consumers of alcohol.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Estados Unidos , Humanos , Sri Lanka/epidemiologia , Estudos de Casos e Controles , National Cancer Institute (U.S.) , Fumar , Consumo de Bebidas Alcoólicas/efeitos adversos , Consumo de Bebidas Alcoólicas/epidemiologia , Fatores de Risco , Neoplasias Bucais/etiologia , Neoplasias Bucais/complicações , Medição de Risco , Carcinoma de Células Escamosas de Cabeça e Pescoço , Carcinoma de Células Escamosas/patologiaRESUMO
The incidence of oral squamous cell carcinoma (OSCC), and its precursor, oral epithelial dysplasia (OED), is on the rise, especially in South Asia. OSCC is the leading cancer in males in Sri Lanka, with >80% diagnosed at advanced clinical stages. Early detection is paramount to improve patient outcome, and saliva testing is a promising non-invasive tool. The aim of this study was to assess salivary interleukins (lL1ß, IL6, and IL8) in OSCC, OED and disease-free controls in a Sri Lankan study cohort. A case-control study with OSCC (n = 37), OED (n = 30) patients and disease-free controls (n = 30) was conducted. Salivary lL1ß, IL6, and IL8 were quantified using enzyme-linked immuno-sorbent assay. Comparisons between different diagnostic groups and potential correlations to risk factors were assessed. Salivary levels for the three tested interleukins increased from disease-free controls through OED, and were highest in OSCC samples. Furthermore, the levels of IL1ß, IL6, and IL8 increased progressively with OED grade. The discrimination between patients (OSCC and OED) and controls, as assessed by AUC of receiver operating characteristic curves, was 0.9 for IL8 (p = 0.0001) and 0.8 for IL6 (p = 0.0001), while IL1ß differentiated OSCC from controls (AUC 0.7, p = 0.006). No significant associations were found between salivary interleukin levels and smoking, alcohol, and betel quid risk factors. Our findings suggest that salivary IL1ß, IL6, and IL8 are associated with disease severity of OED, and are potential biomarkers for predicting disease progression in OED, and the screening of OSCC.
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An important part of realizing a carbon-neutral society using ammonia will be the development of an inexpensive yet efficient catalyst for ammonia synthesis under mild reaction conditions (<400 °C, <10â MPa). Here, we report Fe/K(3)/MgO, fabricated via an impregnation method, as a highly active catalyst for ammonia synthesis under mild reaction conditions (350 °C, 1.0â MPa). At the mentioned conditions, the activity of Fe/K(3)/MgO (17.5â mmol h-1 gcat -1 ) was greater than that of a commercial fused iron catalyst (8.6â mmol h-1 gcat -1 ) currently used in the Haber-Bosch process. K doping was found to increase the ratio of Fe0 on the surface and turnover frequency of Fe in our Fe/K(3)/MgO catalyst. In addition, increasing the pressure to 3.0â MPa at the same temperature led to a significant improvement of the ammonia synthesis rate to 29.6â mmol h-1 gcat -1 , which was higher than that of two more expensive, benchmark Ru-based catalysts, which are also potential alternative catalysts. A kinetics analysis revealed that the addition of K enhanced the ammonia synthesis activity at ≥300 °C by changing the main adsorbed species from NH to N which can accelerate dissociative adsorption of nitrogen as the rate limiting step in ammonia synthesis.
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BACKGROUND: The incidence of oral squamous cell carcinoma (OSCC) is very high in South Asia and Vascular endothelial growth factor (VEGF) is one of the key factors essential for cancer growth. The importance of VEGF-A and VEGF Receptor 2(VEGFR-2) in oral cancer pathophysiology is yet to be decided. Vascular Endothelial Growth Factor A (VEGF-A) is the main factor concerned in angiogenesis in tumors, but its role in Oral Squamous Cell Carcinoma (OSCC) is still debatable. Our study aimed to determine the role of VEGF-A and VEGFR-2 in OSCC. METHODS: Blood from 30 patients with primary OSCC and 1:1 age-sex-matched controls was subjected to qPCR and ELISA to detect VEGF-A gene expression and serum level. Tumors of the 30 patients were investigated for VEGF Receptor-2 (VEGFR-2) expression and were analyzed using Image J software version 1.52 for DAB percentage (DAB-P) area and optical density (OD). RESULTS: VEGF-A relative gene expression among patients was 2.43-fold higher compared to the healthy control group. Well-differentiated had a 1.98-fold increment, while poorly differentiated had a 3.58-fold increment. Serum VEGF-A was significantly elevated among the patients compared to controls (458.7 vs 253.2, p=0.0225). Poorly differentiated had a higher serum VEGF concentration (1262.0±354.7pg/ml) compared with other two. Mean VEGFR-2 DAB-P level in OSCC was 42.41±5.61(p=0.15). Well-differentiated had a DAB-P of 41.20±5.32 while poorly differentiated had DAB-P 46.21±3.78. The mean OD in OSCC was 0.54±0.16. VEGFR-2 OD in well and poorly differentiated OSCC were 0.48±0.12 and 0.68±0.17, respectively. CONCLUSIONS: VEGF-A gene expression, serum levels, and tissue VEGFR-2 levels correlated linearly with the stage and grade of the tumor. This study justifies the value of VEGF-A as a potential biomarker in OSCC in early detection of OSCC. More studies are needed to accept the use of VEGF-A.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Humanos , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/irrigação sanguínea , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço , Neoplasias Bucais/metabolismo , Sri Lanka , Biomarcadores , Fatores de Crescimento do Endotélio Vascular , Neovascularização Patológica/metabolismo , Receptor 1 de Fatores de Crescimento do Endotélio Vascular , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
Specific properties of carbon nanotubes, such as their level of agglomeration in the medium and their surface characteristics, can be critical for the physiological response of plants upon application of carbon nanotubes. The correlations among the level of aggregation, the type of functional group on the surface of the carbon nanotubes, and the growth performance of tomato plants are documented.
Assuntos
Aquaporinas/metabolismo , Nanotubos de Carbono/química , Proteínas de Plantas/metabolismo , Solanum lycopersicum/crescimento & desenvolvimento , Solanum lycopersicum/metabolismo , ImmunoblottingRESUMO
The phosphoinositol pathway is one of the major eukaryotic signalling pathways. The metabolite of the phosphoinositol pathway, inositol- (1,4,5) trisphosphate (InsP(3)), is a regulator of plant responses to a wide variety of stresses, including light, drought, cold, and salinity. It was found that the expression of InsP 5-ptase, the enzyme that hydrolyses InsP(3), also dramatically affects the levels of inositol phosphate metabolites and the secondary metabolites in transgenic tomato plants. Tomato plants expressing InsP 5-ptase exhibited a reduction in the levels of several important inositol phosphates, including InsP(1), InsP(2), InsP(3), and InsP(4). Reduced levels of inositol phosphates accompanied an increase in the accumulation of phenylpropanoids (rutin, chlorogenic acid) and ascorbic acid (vitamin C) in the transgenic fruits of tomato plants. The enhanced accumulation of these metabolites in transgenic tomato plants was in direct correspondence with the observed up-regulation of the genes that express the key enzymes of ascorbic acid metabolism (myo-inositol oxygenase, MIOX; L-galactono-γ-lactone dehydrogenase, GLDH) and phenylpropanoid metabolism (chalcone synthase, CHS1; cinnamoyl-CoA shikimate/quinate transferase, HCT). To understand the molecular links between the activation of different branches of plant metabolism and InsP(3) reduction in tomato fruits, the expression of transcription factors known to be involved in light signalling was analysed by real-time RT-PCR. The expression of LeHY5, SIMYB12, and LeELIP was found to be higher in fruits expressing InsP 5-ptase. These results suggest possible interconnections between phosphoinositol metabolism, light signalling, and secondary metabolism in plants. Our study also revealed the biotechnological potential for the genetic improvement of crop plants by the manipulation of the phosphoinositol pathway.
Assuntos
Inositol 1,4,5-Trifosfato/metabolismo , Fosfatos de Inositol/metabolismo , Transdução de Sinal Luminoso/fisiologia , Monoéster Fosfórico Hidrolases/metabolismo , Solanum lycopersicum/fisiologia , Ácido Ascórbico/metabolismo , Secas , Flavonoides/análise , Flavonoides/metabolismo , Frutas/enzimologia , Frutas/genética , Frutas/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Inositol 1,4,5-Trifosfato/análise , Fosfatos de Inositol/análise , Inositol Polifosfato 5-Fosfatases , Solanum lycopersicum/enzimologia , Solanum lycopersicum/genética , Modelos Biológicos , Monoéster Fosfórico Hidrolases/genética , Plantas Geneticamente Modificadas , Estresse Fisiológico/fisiologia , Regulação para Cima/genéticaRESUMO
Background: The global incidence of oral squamous cell carcinoma (OSCC) is on the rise with no improvement seen in survival rates. Tobacco consumption varies depending on geographic location, ethnicity and culture. The present case-controlled study aimed to determine the relative risk of OSCC for different tobacco consumption patterns in a selected Sri Lankan population. Methods: One hundred and five patients with histopathologically confirmed OSCC attending the National Cancer Institute (Apeksha Hospital) of Sri Lanka and 210 age and gender-matched controls from the community responded to an interviewer-administered questionnaire regarding their smoking and betel-quid chewing (with/ without smokeless tobacco) habits were included in the study. The odds ratios (OR) and 95% confidence intervals (CI) were calculated. p<0.05 was considered as statistically significant. Results: The overall risk of OSCC increased 2.93-fold for smokers. Those smoking two packets of cigarettes or more per day (OR=5.56; 95% CI-2.822- 10.984; p=0.000) had more than double the risk of OSCC than those smoking 1-2 packets per day. Smoking for more than 20 years had a 3.4-fold risk of OSCC. Consumption of betel quid containing tobacco (smokeless tobacco) had a 4.26-fold higher risk for OSCC (OR=4.26; 95% CI-2.21-8.21; p=0.000), and the risk increased when all four ingredients (betel leaf, slaked lime, areca nut, and tobacco) were consumed together (OR=4.26; 95% CI-2.34-7.74; p=0.000). The combined effect from concurrent smoking and betel chewing emerged as the highest risk for OSCC (OR=15.34) which significantly exceeded the risks evident for the two habits practised in isolation from each other. Conclusions: Use of smokeless tobacco, consumption of all four ingredients together, duration of smoking, the number of cigarettes smoked per day and combined consumption of betel quid and smoking are significant risk factors in the development of OSCC among Sri Lankans.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Areca/efeitos adversos , Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/etiologia , Humanos , Neoplasias Bucais/epidemiologia , Neoplasias Bucais/etiologia , Neoplasias Bucais/patologia , Fatores de Risco , Carcinoma de Células Escamosas de Cabeça e Pescoço , Sri Lanka/epidemiologia , Nicotiana , Fumar Tabaco/efeitos adversos , Fumar Tabaco/epidemiologiaRESUMO
Ca(2+) is an important second messenger in plant signal transduction pathways regulating stress-induced gene expression. Functional analysis of plant proteins containing Ca(2+)-binding domains (C2 domains) will help us understand the mechanisms behind the role of transcriptional regulators in the Ca(2+) signalling pathway and open new perspectives for crop genetic improvement. We identified a novel transcriptional regulator, a Ca(2+)-dependent lipid-binding protein (AtCLB) containing a C2 domain. AtCLB binds specifically to the promoter of the Arabidopsis thalianol synthase gene (AtTHAS1), whose expression is induced by gravity and light. Here we describe the role of the Atclb gene encoding the AtCLB protein. Expression of the Atclb gene was documented in all analysed tissues of Arabidopsis (leaf, root, stem, flower, and silique) by real-time PCR analysis. Immunofluorescence analysis revealed that AtCLB protein is localized in the nucleus of cells in Arabidopsis root tips. We demonstrated that the AtCLB protein was capable of binding to the membrane lipid ceramide. The role of the Atclb gene in negatively regulating responses to abiotic stress in Arabidopsis thaliana was identified. The loss of the Atclb gene function confers an enhanced drought and salt tolerance and a modified gravitropic response in T-DNA insertion knockout mutant lines. Expression of AtTHAS1 in Atclb knockout mutant lines was increased compared with wild type and a 35S-Atclb overexpression line suggesting AtCLB as a transcriptional repressor of AtTHAS1.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas Repressoras/metabolismo , Estresse Fisiológico , Sequência de Aminoácidos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Ceramidas/metabolismo , DNA Bacteriano/genética , DNA de Plantas/metabolismo , Secas , Ensaio de Desvio de Mobilidade Eletroforética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas/genética , Gravitropismo/efeitos dos fármacos , Gravitropismo/genética , Dados de Sequência Molecular , Mutação/genética , Especificidade de Órgãos/efeitos dos fármacos , Especificidade de Órgãos/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Proteínas Repressoras/química , Proteínas Repressoras/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tolerância ao Sal/efeitos dos fármacos , Tolerância ao Sal/genética , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genéticaRESUMO
Evisceration of bowel through the stoma is a rare complication and only few cases have been reported. Although most cases occur in the context of long-standing parastomal hernias, early evisceration may also occur causing significant morbidity to patients. The reported patient is a 53-year-old male with bronchial asthma who was diagnosed to have metastatic colonic cancer underwent a trephine loop ileostomy for intestinal obstruction. On post-operative Day 7, he developed small bowel evisceration through the ileostomy site. The patient underwent an emergency laparotomy and found to have non-viable prolapsed small bowel segment at the stoma site. Furthermore, there were extensive peritoneal deposits and large para aortic lymph node mass and ascites compromising the peritoneal space. Resection of non-viable small bowel and ileostomy refashioning was carried out. The patient was managed in the intensive care unit and he gained function of the ileostomy on post-operative Day 2. On Day 5, he died due to subsequent pneumonia and worsening acute respiratory distress syndrome. Early parastomal evisceration is an extremely infrequent life-threatening complication that requires urgent treatment. Disseminated cancer, bowel obstruction, poor nutritional status, ascites and exacerbation of bronchial asthma were additional risk factors in our patient.
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During aging and neuromuscular diseases, there is a progressive loss of skeletal muscle volume and function impacting mobility and quality of life. Muscle loss is often associated with denervation and a loss of resident muscle stem cells (satellite cells or MuSCs); however, the relationship between MuSCs and innervation has not been established. Herein, we administered severe neuromuscular trauma to a transgenic murine model that permits MuSC lineage tracing. We show that a subset of MuSCs specifically engraft in a position proximal to the neuromuscular junction (NMJ), the synapse between myofibers and motor neurons, in healthy young adult muscles. In aging and in a mouse model of neuromuscular degeneration (Cu/Zn superoxide dismutase knockout - Sod1-/-), this localized engraftment behavior was reduced. Genetic rescue of motor neurons in Sod1-/- mice reestablished integrity of the NMJ in a manner akin to young muscle and partially restored MuSC ability to engraft into positions proximal to the NMJ. Using single cell RNA-sequencing of MuSCs isolated from aged muscle, we demonstrate that a subset of MuSCs are molecularly distinguishable from MuSCs responding to myofiber injury and share similarity to synaptic myonuclei. Collectively, these data reveal unique features of MuSCs that respond to synaptic perturbations caused by aging and other stressors.
Assuntos
Envelhecimento , Músculo Esquelético/lesões , Mioblastos Esqueléticos/fisiologia , Junção Neuromuscular/fisiologia , Superóxido Dismutase-1/deficiência , Animais , Feminino , Masculino , Camundongos KnockoutRESUMO
During aging, there is a progressive loss of volume and function in skeletal muscle that impacts mobility and quality of life. The repair of skeletal muscle is regulated by tissue-resident stem cells called satellite cells (or muscle stem cells [MuSCs]), but in aging, MuSCs decrease in numbers and regenerative capacity. The transcriptional networks and epigenetic changes that confer diminished regenerative function in MuSCs as a result of natural aging are only partially understood. Herein, we use an integrative genomics approach to profile MuSCs from young and aged animals before and after injury. Integration of these datasets reveals aging impacts multiple regulatory changes through significant differences in gene expression, metabolic flux, chromatin accessibility, and patterns of transcription factor (TF) binding activities. Collectively, these datasets facilitate a deeper understanding of the regulation tissue-resident stem cells use during aging and healing.
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Senescência Celular/genética , Células Satélites de Músculo Esquelético/metabolismo , Células-Tronco/metabolismo , Envelhecimento/metabolismo , Animais , Linhagem Celular , Feminino , Genômica/métodos , Camundongos , Camundongos Endogâmicos C57BL , Células Musculares/metabolismo , Músculo Esquelético/metabolismo , Mioblastos/metabolismo , Regeneração/fisiologiaRESUMO
Head and neck cancer (HNC) is the leading cancer in Sri Lankan males and second most common cancer among Sri Lankan females. This is the first study, to the best of our knowledge, that has focused on investigating the association between TP53 somatic DNA variants, with p53 protein expression and risk factors in a cohort of Sri Lankan patients with HNC. A total of 44 patients with cancer and 20 healthy controls were studied. In total, 36 genomic DNA sequence variants were found, including several novel variants (two deletions in exons 4 and 6, two in the 3' untranslated region and several intronic variants). A total of 14 tumour samples carried pathogenic TP53 mutations. A random selection of 24 samples was analysed immunohistochemically for p53 protein expression. All the samples with point missense variants were strongly immunopositive, whereas, samples with nonsense and frameshift TP53 variants were immunonegative for p53 immunohistochemical staining. Although, the human papilloma virus is a known risk factor for HNC, results from the present study identified an absence or lower level of infection in the Sri Lankan cohort.
Assuntos
Expressão Gênica , Variação Genética , Neoplasias de Cabeça e Pescoço/etiologia , Neoplasias de Cabeça e Pescoço/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Adulto , Idoso , Alelos , Estudos de Coortes , Feminino , Predisposição Genética para Doença , Genótipo , Neoplasias de Cabeça e Pescoço/epidemiologia , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Prevalência , Sri Lanka/epidemiologia , Adulto JovemRESUMO
Women with breast carcinoma diagnosed before 40 years of age with a strong familial risk have a greater prevalence of germline BRCA1 or BRCA2 variants than late onset breast cancer. Previously germline variants in BRCA1 and BRCA2 genes were characterized in a cohort of Sri Lankan breast cancer patients unselected for age of onset. This study focused on young breast cancer patients who were screened for previously identified hotspot regions in BRCA2 gene. A total of 48 young breast cancer patients with family history of cancer and 25 healthy controls were studied. Direct sequencing was used to detect pathogenic and other sequence variants in the hotspot regions of BRCA2 gene. Thirty-six sequence variants including seven pathogenic (c.2411_2412delAA/p.Glu804Valfs*2, c.2500_2501insG/p.Leu834Cysfs*4, c.3881T>G/p.Leu1294*, c.4768A>T/p.Lys1590*, c.5645C>G/p.Ser1882*, c.5747delC/p.His1916Phefs*3, c.6728C>T/p.Ser2243Phe) and two likely pathogenic (c.1922C>T and c.3378A>T) variants, two intronic variants of unknown significance (c.1910-74T>C, c.1910-51G>T), two variants of uncertain significance (c.2324C>T c.5104C>T) and 23 benign variants were detected. Among them, seven were novel (pathogenic 5 and likely pathogenic 2). Prevalence of pathogenic and likely pathogenic variants in the hotspots regions of BRCA2 was 23 and 6.3 % respectively in this cohort. This justifies BRCA2 variant testing in young breast cancer patients with family history of cancer in Sri Lanka.
Assuntos
Proteína BRCA2/genética , Neoplasias da Mama/genética , Predisposição Genética para Doença/genética , Adulto , Éxons/genética , Feminino , Genes BRCA2 , Humanos , Linhagem , Sri Lanka , Adulto JovemRESUMO
Carbon nanotubes have shown promise as regulators of seed germination and plant growth. Here, we demonstrate that multiwalled carbon nanotubes (MWCNTs) have the ability to enhance the growth of tobacco cell culture (55-64% increase over control) in a wide range of concentrations (5-500 µg/mL). Activated carbon (AC) stimulated cell growth (16% increase) only at low concentrations (5 µg/mL) while dramatically inhibited the cellular growth at higher concentrations (100-500 µg/mL). We found a correlation between the activation of cells growth exposed to MWCNTs and the upregulation of genes involved in cell division/cell wall formation and water transport. The expression of the tobacco aquaporin (NtPIP1) gene, as well as production of the NtPIP1 protein, significantly increased in cells exposed to MWCNTs compared to control cells or those exposed to AC. The expression of marker genes for cell division (CycB) and cell wall extension (NtLRX1) was also up-regulated in cells exposed to MWCNTs compared to control cells or those exposed to activated carbon only.