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1.
Biomicrofluidics ; 18(1): 014106, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38420041

ABSTRACT

Droplet digital PCR (ddPCR) is a technique in which PCR reaction is divided into thousands of nanoliter-sized droplets and has proven to be a great tool in virus diagnostics. Compared to the gold standard system quantitative real-time PCR (RT-qPCR), ddPCR functions particularly well when dealing with samples with low template counts, such as viral concentration. This feature makes the technique suitable for early detection of the virus. In this study, a novel portable PDMS ddPCR chip is introduced. The chip functions without external pumps using manual pressurization with a multichannel pipet. The created droplets are monodispersed and form a monolayer on the chip's collection chamber, from where they can be effortlessly imaged. Droplets were analyzed and counted using artificial intelligence. The use of the manually pressurized chip was demonstrated for a SARS-CoV-2 assay, which takes advantage of isothermal strand invasion-based amplification (SIBA) technology, allowing quick and accurate, even point-of-care analysis of the sample. The results demonstrate that SIBA assays can be divided into nanoliter-sized droplets and used as quantitative assays, giving an approximation of the samples' viral count.

2.
Haematologica ; 109(4): 1171-1183, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-37646663

ABSTRACT

The transcription factor MYC is a well-described oncogene with an important role in lymphomagenesis, but its significance for clinical outcome in mantle cell lymphoma (MCL) remains to be determined. We performed an investigation of the expression of MYC protein in a cohort of 251 MCL patients complemented by analyses of structural aberrations and mRNA, in a sub-cohort of patients. Fourteen percent (n=35) of patients showed high MYC protein expression with >20% positive cells (MYChigh), among whom only one translocation was identified, and 86% (n=216) of patients showed low MYC protein expression. Low copy number gains of MYC were detected in ten patients, but with no correlation to MYC protein levels. However, MYC mRNA levels correlated significantly to MYC protein levels with a R2 value of 0.76. Patients with a MYChigh tumor had both an independent inferior overall survival and an inferior progression-free survival (hazard ratio [HR]=2.03, 95% confidence interval [95% CI]: 1.2-3.4 and HR=2.2, 95% CI: 1.04-4.6, respectively) when adjusted for additional high-risk features. Patients with MYChigh tumors also tended to have additional high-risk features and to be older at diagnosis. A subgroup of 13 patients had concomitant MYChigh expression and TP53/p53 alterations and a substantially increased risk of progression (HR=16.9, 95% CI: 7.4-38.3) and death (HR=7.8, 95% CI: 4.4-14.1) with an average overall survival of only 0.9 years. In summary, we found that at diagnosis a subset of MCL patients (14%) overexpressed MYC protein, and had a poor prognosis but that MYC rearrangements were rare. Tumors with concurrent MYC overexpression and TP53/p53 alterations pinpointed MCL patients with a dismal prognosis with a median overall survival of less than 3 years. We propose that MYC needs to be assessed beyond the current high-risk factors in MCL in order to identify cases in need of alternative treatment.


Subject(s)
Lymphoma, Mantle-Cell , Adult , Humans , Cell Proliferation , Lymphoma, Mantle-Cell/diagnosis , Lymphoma, Mantle-Cell/genetics , Prognosis , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-myc/metabolism , RNA, Messenger , Translocation, Genetic , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
3.
Molecules ; 28(23)2023 Nov 24.
Article in English | MEDLINE | ID: mdl-38067489

ABSTRACT

Pharmaceutical companies are investigating more source matrices for natural bioactive chemicals. Friedelin (friedelan-3-one) is a pentacyclic triterpene isolated from various plant species from different families as well as mosses and lichen. The fundamental compounds of these friedelane triterpenoids are abundantly found in cork tissues and leaf materials of diverse plant genera such as Celastraceae, Asteraceae, Fabaceae, and Myrtaceae. They possess many pharmacological effects, including anti-inflammatory, antioxidant, anticancer, and antimicrobial activities. Friedelin also has an anti-insect effect and the ability to alter the soil microbial ecology, making it vital to agriculture. Ultrasound, microwave, supercritical fluid, ionic liquid, and acid hydrolysis extract friedelin with reduced environmental impact. Recently, the high demand for friedelin has led to the development of CRISPR/Cas9 technology and gene overexpression plasmids to produce friedelin using genetically engineered yeast. Friedelin with low cytotoxicity to normal cells can be the best phytochemical for the drug of choice. The review summarizes the structural interpretation, biosynthesis, physicochemical properties, quantification, and various forms of pharmacological significance.


Subject(s)
Triterpenes , Humans , Triterpenes/chemistry , Anti-Inflammatory Agents , Antioxidants/pharmacology , Phytochemicals
4.
Diagnostics (Basel) ; 13(14)2023 Jul 10.
Article in English | MEDLINE | ID: mdl-37510069

ABSTRACT

Breast cancer is the most prevalent neoplasia among women, with early and accurate diagnosis critical for effective treatment. In clinical practice, however, the subjective nature of histological grading of infiltrating ductal adenocarcinoma of the breast (DAC-NOS) often leads to inconsistencies among pathologists, posing a significant challenge to achieving optimal patient outcomes. Our study aimed to address this reproducibility problem by leveraging artificial intelligence (AI). We trained a deep-learning model using a convolutional neural network-based algorithm (CNN-bA) on 100 whole slide images (WSIs) of DAC-NOS from the Cancer Genome Atlas Breast Invasive Carcinoma (TCGA-BRCA) dataset. Our model demonstrated high precision, sensitivity, and F1 score across different grading components in about 17.5 h with 19,000 iterations. However, the agreement between the model's grading and that of general pathologists varied, showing the highest agreement for the mitotic count score. These findings suggest that AI has the potential to enhance the accuracy and reproducibility of breast cancer grading, warranting further refinement and validation of this approach.

5.
Pak J Med Sci ; 39(4): 956-960, 2023.
Article in English | MEDLINE | ID: mdl-37492295

ABSTRACT

Objective: To determine correlation of HbA1c with serum iron and transferrin saturation in non-diabetic patients with iron deficiency. Methods: This cross-sectional comparative study was conducted at Dr Ruth KM Pfau Civil Hospital Karachi from 15th September 2021 to 14th March 2022, on non-diabetic patients based on fasting blood sugar (FBS) of <100 mg/dl. Patients were divided into two groups. Group one included patients having iron deficiency anemia (ID), whereas group two included same number of age and sex matched healthy subjects taken as controls, without ID. Blood sample was taken for HbA1c, CBC, serum iron and total iron binding capacity. Transferrin saturation (TSAT) was calculated. Comparison of quantitative variables with ID and non-ID group was done by Student's t-test. Correlation of HbA1c with iron &TSAT was done in both groups using Kendal tau-b test, as data was not normally distributed. Results: Out of 230 patients, 83 (36.1%) were males while 147(63.9%) were females. Mean age of patients was 43.7±13.28 years. Mean HbA1c level was significantly high in ID group (5.89±0.43) as compared to non-ID group (5.52±0.50) with a p-value <.001. The HbA1c levels correlated negatively with hemoglobin, serum iron levels and transferrin saturation with a p-value <.001. Conclusion: Low serum Iron and TSAT was related to elevation in HbA1c value. Iron deficiency needs to be corrected before HbA1c interpretation.

6.
Front Mol Neurosci ; 16: 1140785, 2023.
Article in English | MEDLINE | ID: mdl-37415832

ABSTRACT

The activity-regulated cytoskeleton-associated (Arc) protein is essential for synaptic plasticity and memory formation. The Arc gene, which contains remnants of a structural GAG retrotransposon sequence, produces a protein that self-assembles into capsid-like structures harboring Arc mRNA. Arc capsids, released from neurons, have been proposed as a novel intercellular mechanism for mRNA transmission. Nevertheless, evidence for intercellular transport of Arc in the mammalian brain is still lacking. To enable the tracking of Arc molecules from individual neurons in vivo, we devised an adeno-associated virus (AAV) mediated approach to tag the N-terminal of the mouse Arc protein with a fluorescent reporter using CRISPR/Cas9 homologous independent targeted integration (HITI). We show that a sequence coding for mCherry can successfully be knocked in at the 5' end of the Arc open reading frame. While nine spCas9 gene editing sites surround the Arc start codon, the accuracy of the editing was highly sequence-dependent, with only a single target resulting in an in-frame reporter integration. When inducing long-term potentiation (LTP) in the hippocampus, we observed an increase of Arc protein highly correlated with an increase in fluorescent intensity and the number of mCherry-positive cells. By proximity ligation assay (PLA), we demonstrated that the mCherry-Arc fusion protein retains the Arc function by interacting with the transmembrane protein stargazin in postsynaptic spines. Finally, we recorded mCherry-Arc interaction with presynaptic protein Bassoon in mCherry-negative surrounding neurons at close proximity to mCherry-positive spines of edited neurons. This is the first study to provide support for inter-neuronal in vivo transfer of Arc in the mammalian brain.

7.
Am J Pathol ; 193(8): 1072-1080, 2023 08.
Article in English | MEDLINE | ID: mdl-37236505

ABSTRACT

The incidence of nonalcoholic fatty liver disease is a continuously growing health problem worldwide, along with obesity. Therefore, novel methods to both efficiently study the manifestation of nonalcoholic fatty liver disease and to analyze drug efficacy in preclinical models are needed. The present study developed a deep neural network-based model to quantify microvesicular and macrovesicular steatosis in the liver on hematoxylin-eosin-stained whole slide images, using the cloud-based platform, Aiforia Create. The training data included a total of 101 whole slide images from dietary interventions of wild-type mice and from two genetically modified mouse models with steatosis. The algorithm was trained for the following: to detect liver parenchyma, to exclude the blood vessels and any artefacts generated during tissue processing and image acquisition, to recognize and differentiate the areas of microvesicular and macrovesicular steatosis, and to quantify the recognized tissue area. The results of the image analysis replicated well the evaluation by expert pathologists and correlated well with the liver fat content measured by EchoMRI ex vivo, and the correlation with total liver triglycerides was notable. In conclusion, the developed deep learning-based model is a novel tool for studying liver steatosis in mouse models on paraffin sections and, thus, can facilitate reliable quantification of the amount of steatosis in large preclinical study cohorts.


Subject(s)
Deep Learning , Non-alcoholic Fatty Liver Disease , Mice , Animals , Non-alcoholic Fatty Liver Disease/diagnostic imaging , Liver , Neural Networks, Computer , Algorithms , Disease Models, Animal
8.
Sensors (Basel) ; 23(1)2022 Dec 30.
Article in English | MEDLINE | ID: mdl-36616998

ABSTRACT

In this paper, we report a fast, linear wide-range hybrid flexible sensor based on a novel composite of strontium titanate (SrTiO3) and poly 3,4 ethylenedioxythiophene polystyrene sulfonate (PEDOT: PSS) as a sensing layer. Inter-digitate electrodes (IDEs) were printed for humidity monitoring (finger: 250 µm; spacing: 140 µm; length: 8 mm) whilst a meander-based pattern was printed for the temperature measurement (meander thickness: 180 µm; spacing: 400 µm) on each side of the PET substrate using silver ink. Moreover, active layers with different concentration ratios were coated on the electrodes using a spray coating technique. The as-developed sensor showed an excellent performance, with a humidity measurement range of (10-90% RH) and temperature measurement range of (25-90 °C) with a fast response (humidity: 5 s; temperature: 4.2 s) and recovery time (humidity: 8 s; temperature: 4.4 s). The reliability of the sensor during mechanical bending of up to 5.5 mm was validated with a reliable performance. The sensor was also used in real-world applications to measure human respiration. For this, a suggested sensor-based autonomous wireless node was included in a 3D-printed mask. The manufactured sensor was an excellent contender for wearable and environmental applications because of its exceptional performance, which allowed for the simultaneous measurement of both quantities by a single sensing device.


Subject(s)
Printing, Three-Dimensional , Wearable Electronic Devices , Humans , Humidity , Reproducibility of Results , Temperature
9.
Mol Biol Cell ; 32(12): 1158-1170, 2021 06 01.
Article in English | MEDLINE | ID: mdl-33826365

ABSTRACT

The endoplasmic reticulum (ER) is composed of a controlled ratio of sheets and tubules, which are maintained by several proteins with multiple functions. Reticulons (RTNs), especially RTN4, and DP1/Yop1p family members are known to induce ER membrane curvature. RTN4B is the main RTN4 isoform expressed in nonneuronal cells. In this study, we identified FAM134C as a RTN4B interacting protein in mammalian, nonneuronal cells. FAM134C localized specifically to the ER tubules and sheet edges. Ultrastructural analysis revealed that overexpression of FAM134C induced the formation of unbranched, long tubules or dense globular structures composed of heavily branched narrow tubules. In both cases, tubules were nonmotile. ER tubulation was dependent on the reticulon homology domain (RHD) close to the N-terminus. FAM134C plays a role in the autophagy pathway as its level elevated significantly upon amino acid starvation but not during ER stress. Moreover, FAM134C depletion reduced the number and size of autophagic structures and the amount of ER as a cargo within autophagic structures under starvation conditions. Dominant-negative expression of FAM134C forms with mutated RHD or LC3 interacting region also led to a reduced number of autophagic structures. Our results suggest that FAM134C provides a link between regulation of ER architecture and ER turnover by promoting ER tubulation required for subsequent ER fragmentation and engulfment into autophagosomes.


Subject(s)
Autophagy-Related Proteins/physiology , Autophagy , Endoplasmic Reticulum/metabolism , Membrane Proteins/physiology , Nogo Proteins/metabolism , Autophagy-Related Proteins/genetics , Cell Line , Endoplasmic Reticulum/physiology , HEK293 Cells , HeLa Cells , Humans , Membrane Proteins/genetics , Protein Domains
10.
Pak J Pharm Sci ; 33(4(Supplementary)): 1771-1777, 2020 Jul.
Article in English | MEDLINE | ID: mdl-33612460

ABSTRACT

CYP2C9 is an important member of the cytochrome P450 gene family involved in the metabolism of 15% of the drugs including an oral antidiabetic agent sulfonylurea. This study aims to investigate the frequency of CYP2C9*2 and CYP2C9*3 alleles of the gene in the sulfonylurea treated diabetic subjects in Pakistan. Briefly, total 105 patients were included in the study and segregated as control (24) and test (81) based on the clinical manifestations after taking sulfonylurea. Genomic DNA was extracted from blood of the subjects and amplified using CYP2C9 specific primers for exon 3 and exon 7 and then subjected to DNA sequencing. Alignment of the sequences with the reference sequence shows presence of CYP2C9*3/*3, CYP2C9*1/*3 and CYP2C9*1/*2 genotypes in the test cases but only the latter two were found in the control cases. In addition a novel allele, CYP2C9*61 in the heterozygous state, was also identified frequently in the test cases. Molecular structure comparison also showed variations in the structural features of protein encoded by the allelic variants. To the best of our knowledge, the present data is the first report for CYP2C9 allelic variations in the indigenous diabetic subjects and also report the existence of novel allelic variant of CYP2C9, CYP2C9*61.


Subject(s)
Cytochrome P-450 CYP2C9/genetics , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/genetics , Polymorphism, Genetic/genetics , Sulfonylurea Compounds/therapeutic use , Adult , Aged , Alleles , Case-Control Studies , Female , Gene Frequency/genetics , Genotype , Humans , Hypoglycemia/drug therapy , Hypoglycemia/genetics , Hypoglycemic Agents/therapeutic use , Male , Middle Aged , Pakistan , Pharmacogenetics/methods
11.
Mol Biol Cell ; 30(12): 1377-1389, 2019 06 01.
Article in English | MEDLINE | ID: mdl-30995177

ABSTRACT

The endoplasmic reticulum (ER) is extensively remodeled during metazoan open mitosis. However, whether the ER becomes more tubular or more cisternal during mitosis is controversial, and dedicated factors governing the morphology of the mitotic ER have remained elusive. Here, we describe the ER membrane proteins REEP3 and REEP4 as major determinants of ER morphology in metaphase cells. REEP3/4 are specifically required for generating the high-curvature morphology of mitotic ER and promote ER tubulation through their reticulon homology domains (RHDs). This ER-shaping activity of REEP3/4 is distinct from their previously described function to clear ER from metaphase chromatin. We further show that related REEP proteins do not contribute to mitotic ER shaping and provide evidence that the REEP3/4 carboxyterminus mediates regulation of the proteins. These findings confirm that ER converts to higher curvature during mitosis, identify REEP3/4 as specific and crucial morphogenic factors mediating ER tubulation during mitosis, and define the first cell cycle-specific role for RHD proteins.


Subject(s)
Endoplasmic Reticulum/metabolism , Membrane Transport Proteins/metabolism , Mitosis , Amino Acid Sequence , Chromatin/metabolism , Endoplasmic Reticulum/ultrastructure , HeLa Cells , Humans , Membrane Transport Proteins/chemistry , Metaphase , Protein Domains
12.
Sci Rep ; 6: 35969, 2016 10 27.
Article in English | MEDLINE | ID: mdl-27786289

ABSTRACT

Reticulons (RTNs) are a large family of membrane associated proteins with various functions. NOGO-A/RTN4A has a well-known function in limiting neurite outgrowth and restricting the plasticity of the mammalian central nervous system. On the other hand, Reticulon 4 proteins were shown to be involved in forming and maintaining endoplasmic reticulum (ER) tubules. Using comparative transcriptome analysis and qPCR, we show here that NOGO-B/RTN4B and NOGO-A/RTN4A are simultaneously expressed in cultured epithelial, fibroblast and neuronal cells. Electron tomography combined with immunolabelling reveal that both isoforms localize preferably to curved membranes on ER tubules and sheet edges. Morphological analysis of cells with manipulated levels of NOGO-B/RTN4B revealed that it is required for maintenance of normal ER shape; over-expression changes the sheet/tubule balance strongly towards tubules and causes the deformation of the cell shape while depletion of the protein induces formation of large peripheral ER sheets.


Subject(s)
Endoplasmic Reticulum/metabolism , Nogo Proteins/genetics , Animals , Cell Line , Cell Shape , Cells, Cultured , Endoplasmic Reticulum/ultrastructure , Epithelial Cells/metabolism , Epithelial Cells/ultrastructure , Fibroblasts/metabolism , Fibroblasts/ultrastructure , Gene Expression Profiling , Humans , Mice , Microscopy, Immunoelectron , NIH 3T3 Cells , Neurons/metabolism , Neurons/ultrastructure , Nogo Proteins/antagonists & inhibitors , Nogo Proteins/metabolism , Protein Isoforms/genetics , Real-Time Polymerase Chain Reaction
13.
PLoS Biol ; 14(1): e1002340, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26727152

ABSTRACT

Understanding the structure-function relationship of cells and organelles in their natural context requires multidimensional imaging. As techniques for multimodal 3-D imaging have become more accessible, effective processing, visualization, and analysis of large datasets are posing a bottleneck for the workflow. Here, we present a new software package for high-performance segmentation and image processing of multidimensional datasets that improves and facilitates the full utilization and quantitative analysis of acquired data, which is freely available from a dedicated website. The open-source environment enables modification and insertion of new plug-ins to customize the program for specific needs. We provide practical examples of program features used for processing, segmentation and analysis of light and electron microscopy datasets, and detailed tutorials to enable users to rapidly and thoroughly learn how to use the program.


Subject(s)
Image Processing, Computer-Assisted , Software , Microscopy
14.
Pak J Med Sci ; 31(2): 462-6, 2015.
Article in English | MEDLINE | ID: mdl-26101512

ABSTRACT

OBJECTIVES: To determine outcome in primary and secondary glomerular diseases at one year follow up. METHODS: Study design is observational cohort, done in out-patient department, Dow Iinternational Medical College, DUHS. All information gathered on a proforma. All patients with dipstick positive proteinuria and clinical glomerular disease were included in study. Patients with no proteinuria were excluded so were patients with stage 5 CKD. Patients were followed for proteinuria and renal insufficiency at completion of one year follow up. Statistical analysis was done on SPSS version 16. RESULT: Total number of patients who completed one year follow up was 173. Mean age of patients was 51.67+ 10.16 (range 15 to 75 years). Ninety two (53.2%), were males and 81(46.8%) were females, ratio being 1.1: 1.0. Mean weight of our patients was 67.43+ 14.13 Kg, (35 to 107 kg). Commonest cause of glomerular disease in our patient was diabetic nephropathy which was seen in 94.2% patients. Commonest associated problem with glomerular disease was hypertension seen in 66.5% of patients. Four out of 173 patients had stage 5 CKD at end of follow up at one year while quantitativ proteinuria remained same at one year follow up. CONCLUSION: One year follow up is critical for patients with glomerular disease associated with stage 4 CKD as progression to end stage renal failure may be seen within one year in these patients.

15.
Pak J Med Sci ; 31(1): 95-9, 2015.
Article in English | MEDLINE | ID: mdl-25878622

ABSTRACT

OBJECTIVE: Vacuum assisted closure is a reported technique to manage complex wounds. We have utilized this technique by using simple locally available material in the management of our patients on outpatient basis. The objective of this study is to present our experience. METHODS: This study was conducted from June 2011 to June 2013 at Dow University Hospital and Aga Khan University Hospital, Karachi. There were 38 patients managed with vacuum assisted closure. Mean age was 56±7.8 years. Twenty three patients presented with necrotizing fasciitis and 15 patients with gangrene. Lower limbs were involved in majority of the patients. Debridement or amputations were done. Vacuum dressing was changed twice weekly in outpatient department. Wounds were closed secondarily if possible or covered with split thickness skin graft in another admission. RESULTS: All the wounds were successfully granulated at the end of vacuum therapy. Mean hospital stay was 7.5 days. Vacuum dressing was applied for a mean of 20 days. There was reduction in the size of the wound. Thirteen patients underwent secondary closure of the wound under local anesthesia, 18 patients required coverage with split thickness skin graft and 7 patients healed with secondary intention. CONCLUSION: Vacuum assisted closure appeared to be an effective method to manage complex diabetic wounds requiring sterile wound environment.

16.
Pak J Med Sci ; 30(1): 77-80, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24639835

ABSTRACT

OBJECTIVES: (1) To determine frequency of urinary tract infection among pyuric diabetic patients. (2) To determine sterile pyuria frequency among pyuric diabetic patients. (3) To determine factors predisposing to urinary tract infection. METHODS: This is a non randomized, prospective observational study done in tertiary care set up of Dow University of Health Sciences, Karachi. Data collection done from June 2013 till August 2013. Sampling was done by convenient method, sample size of 97. Inclusion criteria was all adult (above 16) patients with diabetes mellitus and pyuria (more than 4 pus cells /HPF) whose urine culture report was also available. Verbal consent was sought from patients. All data was collected on a Performa. Data was maintained and analyzed on SPSS version 16. RESULTS: Total number of pyuric diabetic patients in study was 97. Frequency of Urinary tract infection was 59/97 (60.82%), prevalence of culture negative sterile pyuria was found 38/97 (39.17%). Urinary tract infection was found to be more in females with lower urinary tract symptoms and flank pains. Stone disease, obstructed pelvicalyceal system, proteinuria, high serum creatinine and positive nitrites were found more in culture positive patients than in culture negative pyuric patients. CONCLUSIONS: Pyuric diabetic patients in our study population were found to have culture positive UTI in 60.82% and culture negative sterile pyuria among 39.17% of patients. UTI was found more in females, in symptomatic patient and with abnormal urinary tract anatomy and function.

17.
Neuromuscul Disord ; 22(5): 406-17, 2012 May.
Article in English | MEDLINE | ID: mdl-22284942

ABSTRACT

The genetic defect of mdx mice resembles that of Duchenne muscular dystrophy, although their functional performance and life expectancy is nearly normal. By contrast, mice lacking utrophin and dystrophin (mdx/utrn -/-) are severely affected and die prematurely. Mice with one utrophin allele (mdx/utrn +/-) are more severely affected than mdx mice, but outlive mdx/utrn -/- mice. We subjected mdx/utrn +/+, +/-, -/- and wild type males to a 12week functional test regime of four different functional tests. Mdx/utrn +/+ and +/- mice completed the regime, while mdx/utrn -/- mice died prematurely. Mdx/utrn +/- mice performed significantly worse compared to mdx/utrn +/+ mice in functional tests. Creatine kinase levels, percentage of fibrotic/necrotic tissue, morphology of neuromuscular synapses and expression of biomarker genes were comparable, whereas mdx/utrn +/- and -/- mice had increased levels of regenerating fibers. This makes mdx/utrn +/- mice valuable for testing the benefit of potential therapies on muscle function parameters.


Subject(s)
Dystrophin/metabolism , Motor Activity , Muscle, Skeletal/pathology , Muscular Dystrophy, Animal/genetics , Muscular Dystrophy, Duchenne/genetics , Utrophin/metabolism , Animals , Disease Models, Animal , Dystrophin/deficiency , Mice , Mice, Inbred mdx , Mice, Knockout , Muscle, Skeletal/metabolism , Muscular Dystrophy, Animal/pathology , Muscular Dystrophy, Animal/physiopathology , Muscular Dystrophy, Duchenne/pathology , Muscular Dystrophy, Duchenne/physiopathology , Survival Analysis , Utrophin/deficiency
18.
mBio ; 2(5)2011.
Article in English | MEDLINE | ID: mdl-21972238

ABSTRACT

UNLABELLED: All positive-strand RNA viruses induce membrane structures in their host cells which are thought to serve as suitable microenvironments for viral RNA synthesis. The structures induced by enteroviruses, which are members of the family Picornaviridae, have so far been described as either single- or double-membrane vesicles (DMVs). Aside from the number of delimiting membranes, their exact architecture has also remained elusive due to the limitations of conventional electron microscopy. In this study, we used electron tomography (ET) to solve the three-dimensional (3-D) ultrastructure of these compartments. At different time points postinfection, coxsackievirus B3-infected cells were high-pressure frozen and freeze-substituted for ET analysis. The tomograms showed that during the exponential phase of viral RNA synthesis, closed smooth single-membrane tubules constituted the predominant virus-induced membrane structure, with a minor proportion of DMVs that were either closed or connected to the cytosol in a vase-like configuration. As infection progressed, the DMV number steadily increased, while the tubular single-membrane structures gradually disappeared. Late in infection, complex multilamellar structures, previously unreported, became apparent in the cytoplasm. Serial tomography disclosed that their basic unit is a DMV, which is enwrapped by one or multiple cisternae. ET also revealed striking intermediate structures that strongly support the conversion of single-membrane tubules into double-membrane and multilamellar structures by a process of membrane apposition, enwrapping, and fusion. Collectively, our work unravels the sequential appearance of distinct enterovirus-induced replication structures, elucidates their detailed 3-D architecture, and provides the basis for a model for their transformation during the course of infection. IMPORTANCE: Positive-strand RNA viruses hijack specific intracellular membranes and remodel them into special structures that support viral RNA synthesis. The ultrastructural characterization of these "replication structures" is key to understanding their precise role. Here, we resolved the three-dimensional architecture of enterovirus-induced membranous compartments and their transformation in time by applying electron tomography to cells infected with coxsackievirus B3 (CVB3). Our results show that closed single-membrane tubules are the predominant initial virus-induced structure, whereas double-membrane vesicles (DMVs) become increasingly abundant at the expense of these tubules as infection progresses. Additionally, more complex multilamellar structures appear late in infection. Based on compelling intermediate structures in our tomograms, we propose a model for transformation from the tubules to DMVs and multilamellar structures via enwrapping events. Our work provides an in-depth analysis of the development of an unsuspected variety of distinct replication structures during the course of CVB3 infection.


Subject(s)
Cell Transformation, Viral , Enterovirus B, Human/physiology , Enterovirus Infections/virology , Intracellular Membranes/ultrastructure , Intracellular Membranes/virology , Virus Replication , Animals , Chlorocebus aethiops , Electron Microscope Tomography , Enterovirus B, Human/genetics , Humans , Vero Cells
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