RESUMO
The ATP-dependent chromatin remodeling proteins play an important role in DNA repair. The energy released by ATP hydrolysis is used for myriad functions ranging from nucleosome repositioning and nucleosome eviction to histone variant exchange. In addition, the distant member of the family, SMARCAL1, uses the energy to reanneal stalled replication forks in response to DNA damage. Biophysical studies have shown that this protein has the unique ability to recognize and bind specifically to DNA structures possessing double-strand to single-strand transition regions. Mutations in SMARCAL1 have been linked to Schimke immuno-osseous dysplasia, an autosomal recessive disorder that exhibits variable penetrance and expressivity. It has long been hypothesized that the variable expressivity and pleiotropic phenotypes observed in the patients might be due to the ability of SMARCAL1 to co-regulate the expression of a subset of genes within the genome. Recently, the role of SMARCAL1 in regulating transcription has been delineated. In this review, we discuss the biophysical and functional properties of the protein that help it to transcriptionally co-regulate DNA damage response as well as to bind to the stalled replication fork and stabilize it, thus ensuring genomic stability. We also discuss the role of SMARCAL1 in cancer and the possibility of using this protein as a chemotherapeutic target.
Assuntos
DNA Helicases/fisiologia , Replicação do DNA , Motivos de Aminoácidos , Animais , Arteriosclerose/genética , Bovinos , DNA Helicases/química , DNA Helicases/genética , DNA Helicases/metabolismo , Reparo do DNA/fisiologia , Instabilidade Genômica , Histonas/genética , Histonas/metabolismo , Humanos , Mutação , Neoplasias/genética , Síndrome Nefrótica/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Osteocondrodisplasias/genética , Doenças da Imunodeficiência Primária/genética , Embolia Pulmonar/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ativação TranscricionalRESUMO
BACKGROUND/AIM: Helicobacter pylori (H. pylori) colonization affects the gastric microbiome, causing gastrointestinal (GI) diseases. Modern sequencing technology provides insights into GI microbe interaction with H. pylori and their metabolic pathways in causing GI diseases. We aim to compare the gastric microbiota alteration due to H. pylori infection in patients suffering from GI diseases. MATERIALS AND METHODS: Genomic DNA were isolated from gastric antrum tissue from 37 H.pylori-infected patients diagnosed with GERD, duodenal ulcers, and gastritis. We conducted the genomic library preparation and sequencing of the amplified product using 16S rRNA NGS analysis. Using microbiome analyst tool diversity analysis, random forest analysis and ANOVA were conducted to find out the comparison of microbial abundance. We have also conducted functional pathway prediction analysis using PICRUSt. RESULTS: Metagenomic analysis shows high bacterial diversity in H. pylori-positive gastritis patients. Streptococcus infantis and Neisseria subflava were significantly higher in duodenal ulcer (DU) and gastritis groups. Acinetobacter lwoffii and Helicobacter pullorum were significantly high in the gastritis group only. The functional metabolic pathway analyses revealed that gastroesophageal reflux disease (GERD) samples were significantly enriched with the energy metabolism and xenobiotic biodegradation and metabolism pathways, whereas fructose-1,6-bisphosphatase III was found less in gastritis and DU groups. CONCLUSION: There is a difference in microbiota composition in different disease outcomes. We found positive association between microbial diversity and H. pylori in gastritis group only, whereas negative association was found in DU and GERD groups. The functional metabolic pathway analysis revealed significant differences in various disease outcomes.
RESUMO
Cell-based therapy has been used to treat stroke related disorders, which have no treatment options available 4.5 hours after onset. Although the administration of tissue plasminogen activator and mechanical thrombectomy are potent treatments, their clinical implementation is limited within the available time. Here, we aimed to use induced pluripotent stem cell-derived neural progenitor cells (NPCs) for stroke treatment with higher delivery efficiency in stroke areas, which will improve the therapeutic effect. E-selectin binding oligopeptide (Esbp) was conjugated with poly(ethylene glycol)-conjugated-lipid (Esbp-PEG-lipid) with different molecular weights of PEG (5 and 40 kDa) for cell surface modification. Then, we optimized the cell surface modification of NPCs by studying cell-binding ability onto the model surfaces of stroke areas, such as recombinant E-selectin-immobilized surfaces and TNF-α activated endothelium. As a result, the cell surface modification of NPCs with Esbp-PEG-lipid was found to induce specific intercellular interactions with the activated endothelium through the binding of Esbp with E-selectin. Additionally, the shorter PEG spacer was suitable for intercellular interactions. Thus, our technique shows potential for use in cell therapy with enhanced cell accumulation in infarct areas.
Assuntos
Células-Tronco Pluripotentes Induzidas , Células-Tronco Neurais , Células Endoteliais , Oligopeptídeos , Ativador de Plasminogênio TecidualRESUMO
BACKGROUND: Cardiac complications are a leading cause of maternal death. Cardiac imaging with echocardiography is important for prompt diagnosis, but it is not available in many low-resource settings. The aim of this study was to determine whether focused cardiac ultrasound performed by trained obstetricians and interpreted remotely by experts can identify cardiac abnormalities in pregnant women in low-resource settings. METHODS: A cross-sectional study was conducted among 301 pregnant and postpartum women recruited from 10 hospitals across three states in India. Twenty-two obstetricians were trained in image acquisition using a portable cardiac ultrasound device following a simplified protocol adapted from focus-assessed transthoracic echocardiography protocol. It included parasternal long-axis, parasternal short-axis, and apical four-chamber views on two-dimensional and color Doppler. Independent image interpretation was performed remotely by two experts, in the United Kingdom and India, using a standard semiquantitative assessment protocol. Interrater agreement between the experts was examined using Cohen's κ. Diagnostic accuracy of the method was examined in a subsample for whom both focused and conventional scans were available. RESULTS: Cardiac abnormalities identified using the focused method included valvular abnormalities (27%), rheumatic heart disease (6.6%), derangements in left ventricular size (4.7%) and function (22%), atrial dilatation (19.5%), and pericardial effusion (30%). There was substantial agreement on the cardiac parameters between the two experts, ranging from 93.6% (κ = 0.84) for left ventricular ejection fraction to 100% (κ = 1) for valvular disease. Image quality was graded as good in 79% of parasternal long-axis, 77% of parasternal short-axis and 64% of apical four-chamber views. The chance-corrected κ coefficients indicated fair to moderate agreement (κ = 0.28-0.51) for the image quality parameters. There was good agreement on diagnosis between the focused method and standard echocardiography (78% agreement), compared in 36 participants. CONCLUSIONS: The focused method accurately identified cardiac abnormalities in pregnant women and could be used for screening cardiac problems in obstetric settings.
Assuntos
Insuficiência Cardíaca , Derrame Pericárdico , Gravidez , Feminino , Humanos , Volume Sistólico , Função Ventricular Esquerda , Gestantes , Estudos Transversais , Ecocardiografia/métodos , Insuficiência Cardíaca/diagnóstico por imagemRESUMO
OBJECTIVES: Following a surge in cases of coronavirus disease 2019 (COVID-19) in June 2020, India became the third-worst affected country worldwide. This study aims to analyse the underlying epidemiological situation in India and explain possible impacts of policy and technological changes. METHODS: Secondary data were utilized, including recently published literature from government sources, the COVID-19 India website and local media reports. These data were analysed, with a focus on the impact of policy and technological interventions. RESULTS: The spread of COVID-19 in India was initially characterized by fewer cases and lower case fatality rates compared with numbers in many developed countries, primarily due to a stringent lockdown and a demographic dividend. However, economic constraints forced a staggered lockdown exit strategy, resulting in a spike in COVID-19 cases. This factor, coupled with low spending on health as a percentage of gross domestic product (GDP), created mayhem because of inadequate numbers of hospital beds and ventilators and a lack of medical personnel, especially in the public health sector. Nevertheless, technological advances, supported by a strong research base, helped contain the damage resulting from the pandemic. CONCLUSIONS: Following nationwide lockdown, the Indian economy was hit hard by unemployment and a steep decline in growth. The early implementation of lockdown initially decreased the doubling rate of cases and allowed time to upscale critical medical infrastructure. Measures such as asymptomatic testing, public-private partnerships, and technological advances will be essential until a vaccine can be developed and deployed in India. PUBLIC INTEREST SUMMARY: The spread of COVID-19 in India was initially characterized by lower case numbers and fewer deaths compared with numbers in many developed countries. This was mainly due to a stringent lockdown and demographic factors. However, economic constraints forced a staggered lockdown exit strategy, resulting in a spike in COVID-19 cases in June 2020. Subsequently, India became the third-worst affected country worldwide. Low spending on health as a percentage of gross domestic product (GDP) meant there was a shortage of hospital beds and ventilators and a lack of medical personnel, especially in the public health sector. Nevertheless, technological advances, supported by a strong research base, helped contain the health and economic damage resulting from the pandemic. In the future, measures such as asymptomatic testing, public-private partnerships, and technological advances will be essential until a vaccine against COVID-19 can be developed and rolled-out in India.
RESUMO
Ischemic stroke is a major cause of death and disability worldwide and is expected to increase in the future with the aging population. Currently, there are no clinically available treatments for damage sustained during an ischemic stroke, but much research is being conducted in this area. In this review, we will introduce current ischemic stroke treatments along with their limitations, as well as research on potential short and long-term future treatments. There are advantages and disadvantages in these potential treatments, but our understanding of these methods and their effectiveness in clinical trials are improving. We are confident that some future treatments introduced in this review will become commonly used in clinical settings in the future.
RESUMO
Cell fusion is a fundamental event in various biological processes and has been applied to a number of biotechnologies. However, cell fusion efficiency is still low and strongly depends on cell lines and skills, though some improvements have been made. Our hypothesis is that two distinct cell membranes need to be brought together for cell membrane fusion, which is important for mimicking cell fusion in vitro. Here, we aimed to improve the homogeneous and heterogeneous cell fusion efficiency using a cell-cell attachment technique. We modified cellular membranes with two distinctive poly(ethylene glycol)-lipids (PEG-lipids) carrying oligopeptide, three repeated units of the EIAALEK and KIAALKE sequences (fuE3 and fuK3, respectively), which induce cell-cell attachment. The ratio and area of cell-cell attachment can be controlled through surface modification with fuE3-and fuK3-PEG-lipids by changing the number of each incorporated peptide. By combining this technique with the PEG-induced method, the cell fusion efficiency was significantly improved for homogeneous and heterogeneous cell fusion compared to conventional PEG-induced methods. For homogeneous CCRF-CEM cell fusion, the efficiency increased up to 64% from the 8.4% with the PEG-induced method. In addition, for heterogeneous cell fusion of myeloma cells and splenocytes, the efficiency increased up to 18% from almost zero. Thus, cell membrane fusion could be promoted effectively between closely contacted cell membranes induced by the cell-cell attachment technique.
Assuntos
Lipídeos , Fusão de Membrana , Membrana Celular , Peptídeos , PolietilenoglicóisRESUMO
Metallic materials are used for clinical medical devices such as vascular stents and coils to treat both ischemic and hemorrhagic vascular diseases. An antiplatelet drug is required to avoid thromboembolic complication until metallic surface is covered with a neo-endothelial cell layer. It is important to identify endothelial cell coverage on the metallic surface. However, it is difficult since there are no selective ligands. Here, we used the phage display method to identify peptide ligands that had high affinity for the metallic surface of Ni-Ti stents, Pt-W coils, and Co-Cr stents. The binding assay using fluorescence labeling revealed that several synthetic peptides could bind onto those surfaces. We also chose some oligopeptides for the conjugation onto superparamagnetic iron oxide (SPIO) nanoparticles and liposome-encapsulating SPIO nanoparticles and studied their ability to bind to the stent and coils. By SEM and fluorophotometry, we found that those modified SPIOs and liposomes were selectively bound onto those surfaces. In addition, both treated stents and coils could be detected by magnetic resonance imaging due to the magnetic artifact through the SPIOs and liposomes that were immobilized onto the surface. Thus, we identified metal-binding peptides which may enable to stop antiplatelet therapy after vascular stenting or coiling.
Assuntos
Proteínas de Transporte/metabolismo , Lipossomos/química , Nanopartículas Magnéticas de Óxido de Ferro/química , Metais Pesados/metabolismo , Peptídeos/metabolismo , Stents , Sequência de Aminoácidos , Proteínas de Transporte/química , Técnicas de Visualização da Superfície Celular , Colesterol/química , Metais Pesados/química , Peptídeos/química , Fosfatidiletanolaminas/química , Polietilenoglicóis/química , Ligação ProteicaRESUMO
The ATP-dependent chromatin remodeling factors regulate gene expression. However, it is not known whether these factors regulate each other. Given the ability of these factors to regulate the accessibility of DNA to transcription factors, we postulate that one ATP-dependent chromatin remodeling factor should be able to regulate the transcription of another ATP-dependent chromatin remodeling factor. In this paper, we show that BRG1 and SMARCAL1, both members of the ATP-dependent chromatin remodeling protein family, regulate each other. BRG1 binds to the SMARCAL1 promoter, while SMARCAL1 binds to the brg1 promoter. During DNA damage, the occupancy of SMARCAL1 on the brg1 promoter increases coinciding with an increase in BRG1 occupancy on the SMARCAL1 promoter, leading to increased brg1 and SMARCAL1 transcripts respectively. This is the first report of two ATP-dependent chromatin remodeling factors regulating each other.
Assuntos
DNA Helicases/genética , DNA Helicases/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Dano ao DNA , Regulação da Expressão Gênica , Células HeLa , Humanos , Regiões Promotoras Genéticas , Elementos Reguladores de TranscriçãoRESUMO
SMARCAL1, a member of the SWI2/SNF2 protein family, stabilizes replication forks during DNA damage. In this manuscript, we provide the first evidence that SMARCAL1 is also a transcriptional co-regulator modulating the expression of c-Myc, a transcription factor that regulates 10-15% genes in the human genome. BRG1, SMARCAL1 and RNAPII were found localized onto the c-myc promoter. When HeLa cells were serum starved, the occupancy of SMARCAL1 on the c-myc promoter increased while that of BRG1 and RNAPII decreased correlating with repression of c-myc transcription. Using Active DNA-dependent ATPase A Domain (ADAAD), the bovine homolog of SMARCAL1, we show that the protein can hydrolyze ATP using a specific region upstream of the CT element of the c-myc promoter as a DNA effector. The energy, thereby, released is harnessed to alter the conformation of the promoter DNA. We propose that SMARCAL1 negatively regulates c-myc transcription by altering the conformation of its promoter region during differentiation.