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Azizi E, Bachireddy P, Nguyen VN, Li S, Neuberg DS, Soiffer RJ, Ritz J, Alyea EP, Pe'er D, Wu CJ. Abstract 3371: Mapping the evolution of T cell states during DLI response and resistance using single-cell data and computational tools. Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-3371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Donor lymphocyte infusion (DLI) is a standard of care and potentially curative immunotherapy for relapsed leukemia after allogeneic hematopoietic stem cell transplant (allo-SCT). Despite low response rates for many leukemias, chronic myelogenous leukemia (CML) has historically exhibited an exquisite DLI sensitivity, and we previously reported that durable response to DLI was associated with reversal of exhaustion of bone marrow (BM) -infiltrating T cells (Bachireddy et al., Blood 2014). Critical questions remain, however, regarding the exact transcriptional states of those T cell subtypes mediating exhaustion, anti-leukemia responses, and resistance to DLI.
To map evolving phenotypic T cell states in situ at single cell resolution, we profiled viable cells isolated from cryopreserved BM mononuclear cells from a median of 3 timepoints before and after DLI from 12 patients with relapsed CML after allo-SCT, including 6 long-term responders to DLI (R’s) and 6 nonresponders (NR’s), using single cell RNA sequencing (scRNA-seq). Using our computational tools for processing and analyzing scRNA-seq data (Azizi et al., Cell 2018), we detected 381,462 cells in total derived from 43 unique patient-timepoints that met our quality metrics.
Because DLI’s anti-leukemic efficacy derives in large part from T cell activity, we sought a more refined characterization of T cells using our tool Biscuit (Azizi et al., Cell 2018) to merge, normalize and cluster T cells. We observed a marked increase in the number of T cell clusters in post-DLI samples compared to matched pre-DLI samples (p<0.001). Both R and NR cases exhibited increases in phenotypic volume induced by DLI (p<1x10-6), suggesting DLI induces multiple, independent gene expression components in both clinical outcomes. However, at both pre- and post-DLI timepoints, phenotypic volumes in R cases were higher than that of NR cases.
Comparing T cell exhaustion between R vs NR cases, we confirmed increased T cell exhaustion signatures in R-pre T cells. Using factor analysis techniques we found that anergy, dysfunction and tolerance are shared factors driving a subset of T cells that are enriched in NRs, suggesting multiple forms of T cell dysfunction in DLI resistance. We found that the clusters dominated by post-DLI R T cells were characterized by greater diversity of T helper subsets (Th1, Tfh, Th2, Th9, and Th22) and enrichment for exhaustion, type I and II IFN pathways, proinflammatory gene sets and CD8 T cell activation. Clusters dominated by NR T cells displayed increases in Th17 and Treg signatures, anergy and tolerance.
These data suggest that (1) pretreatment T cell phenotypic diversity may be important for DLI response; (2) that DLI increases such diversity differently in R’s than in NR’s; (3) while T cell subsets exhibit some overlap pre-therapy, responders and non-responders become increasingly dissimilar post therapy.
Citation Format: Elham Azizi, Pavan Bachireddy, Vinhkhang N. Nguyen, Shuqiang Li, Donna S. Neuberg, Robert J. Soiffer, Jerome Ritz, Edwin P. Alyea III, Dana Pe'er, Catherine J. Wu. Mapping the evolution of T cell states during DLI response and resistance using single-cell data and computational tools [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3371.
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Diallo AB, Nguifo EM, Dhifli W, Azizi E, Prabhakaran S, Tansey W. Selected Papers from the Workshop on Computational Biology: Joint with the International Joint Conference on Artificial Intelligence and the International Conference on Machine Learning, 2018. J Comput Biol 2019; 26:507-508. [DOI: 10.1089/cmb.2019.29020.abd] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Clay FJ, Kuriakose A, Lesche D, Hicks AJ, Zaman H, Azizi E, Ponsford JL, Jayaram M, Hopwood M. Klüver-Bucy Syndrome Following Traumatic Brain Injury: A Systematic Synthesis and Review of Pharmacological Treatment From Cases in Adolescents and Adults. J Neuropsychiatry Clin Neurosci 2019; 31:6-16. [PMID: 30376788 DOI: 10.1176/appi.neuropsych.18050112] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Klüver-Bucy syndrome (KBS) is a rare clinical presentation following traumatic brain injury (TBI). Symptoms include visual agnosia, placidity, hyperorality, sexual hyperactivity, changes in dietary behavior, and hypermetamorphosis. The purpose of this article was to identify and synthesize the available evidence from case reports and case series on the treatment profile of KBS among adolescents and adults after TBI. Four bibliographic databases (MEDLINE OVID, EMBASE, PsycINFO, and SCOPUS) were searched for relevant literature. No date or language restrictions were applied. All case reports containing original data on KBS following TBI among adolescents and adults were included. Articles were evaluated, and data were extracted according to predefined criteria. The literature search identified 24 case reports of KBS post-TBI published between 1968 and 2017. Most case subjects were male (70.1%), and the mean age at injury was 25.1 years (range, 13-67 years). Injury to one or both temporal lobes occurred in most cases. Inappropriate sexual hyperactivity was the most common KBS symptom, followed by a change in dietary behavior and hyperorality. Visual agnosia was the least reported. In 50% of cases, the patient fully recovered from KBS. One-half of all participants described pharmacological management; the most common medication prescribed was carbamazepine. Overall, there was a lack of data available on pharmacotherapy initiation and duration. The complex presentation of KBS presents challenges in terms of treatment options. Although overall individuals who were prescribed carbamazepine had positive outcomes, given the reliance on case reports, it is difficult to make a definitive recommendation to guide clinical practice.
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Bachireddy P, Azizi E, Nguyen VN, Li S, Neuberg D, Soiffer RJ, Ritz J, Alyea EP, Pe'er D, Wu C. Single Cell T Cell Maps of Donor Lymphocyte Infusion (DLI) Response and Resistance. Biol Blood Marrow Transplant 2019. [DOI: 10.1016/j.bbmt.2018.12.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Azizi E, Naji M, Shabani-Nashtaei M, Aligholi A, Najafi A, Amidi F. Association of serum content of 25-hydroxy vitamin D with semen quality in normozoospermic and oligoasthenoteratozoospermic men. Int J Reprod Biomed 2018; 16:689-696. [PMID: 30775684 PMCID: PMC6350849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 07/17/2018] [Accepted: 07/28/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Vitamin D has multifaceted function in human reproductive physiology. It has been revealed that vitamin D is involved in spermatogenesis, and semen quality can be linked to vitamin D status in men. OBJECTIVE Evaluating the correlation of 25-hydroxy vitamin D (25-OHD) levels in serum with basic and advanced semen parameters and essential determinants of spermatozoa function. MATERIALS AND METHODS Participants were categorized, based on semen parameters, into normozoospermic (NS) and oligoasthenoteratozoospermic (OAT) men. Serum level of 25-OHD was measured. Apoptotic status of spermatozoa, mitochondrial membrane potential and reactive oxygen species content of semen were assessed. RESULTS Difference of 25-OHD concentration in serum of NS men versus OAT ones did not meet significance threshold. DNA fragmentation, reactive oxygen species content of semen and mitochondrial membrane potential state revealed significant difference between NS and OAT subjects. There were no significant differences in basic and functional semen parameters when men were stratified based on serum 25-OHD level. Taking both 25-OHD and semen categories (NS and OAT) into consideration did not indicate any significant difference in studied parameters. Total motility of spermatozoa was positively correlated with serum concentration of 25-OHD in all studied subjects. In addition, normal morphology of spermatozoa in NS men revealed a positive and significant correlation with levels of 25-OHD in serum. CONCLUSION Vitamin D may affect motility and morphology of spermatozoa. Lower content of serum vitamin D may affect fertility of men and should be considered in examination of men with abnormal spermogram.
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Azizi E, Stainer MJ, Abel LA. Is experience in multi-genre video game playing accompanied by impulsivity? Acta Psychol (Amst) 2018; 190:78-84. [PMID: 30031355 DOI: 10.1016/j.actpsy.2018.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 06/14/2018] [Accepted: 07/15/2018] [Indexed: 01/27/2023] Open
Abstract
Developing impulsivity has been one of the main concerns thought to arise from the increasing popularity of video gaming. Most of the relevant literature has treated gamers as pure-genre players (i.e. those who play only a specific genre of game). However, it is not clear how impulsivity is associated with different genres of games in multi-genre gamers, given that there is increasing diversity in the games played by individuals. In this study, we compared 33 gamers to 23 non-gamers in a go/no-go task: the Continuous Performance Test (CPT). To evaluate whether or not impulsivity occurs as a trade-off between speed and accuracy, we emphasised fast performance to all participants. Then, to examine the ability to predict impulsivity from game genre-hours, we fitted separate multiple regression models to several dependent variables. As an additional measure, we also compared groups in an antisaccade task. In the CPT, gamers showed a trend towards significantly faster reaction time (RT), accompanied by higher false alarm rate (FAR) and more risk-taking response bias (β), suggesting impulsive responses. Interestingly, there was a significant negative correlation between RT and FAR across all participants, suggesting an overall speed-accuracy trade-off strategy, perhaps driven by the emphasis on speed during task instruction. Moreover, time spent on role playing games (RPG) and real-time strategy (RTS) games better predicted FAR and β than did time spent on action and puzzle games. In the antisaccade task; however, gamers showed a shorter antisaccade latency but a comparable error rate in comparison with non-gamers. There was no specific game genre which could predict performance in the antisaccade task. Altogether, there was no evidence of oculomotor impulsivity in gamers; however, the CPT results suggested the presence of impulsive responses in gamers, which might be the result of a speed-accuracy trade-off. Furthermore, there was a difference in game genres, with time spent on RPG and RTS games being accompanied by greater probability of impulsive responses. Training studies are required to investigate the causality of different video game genres on the development of impulsivity.
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Azizi E, Borzouei S, Soltanian AR. A Nonparametric Bootstrap Confidence Interval for the Prevalence of Undiagnosed Type 2 Diabetes Mellitus in Hamadan, West of Iran. J Res Health Sci 2018; 18:e00421. [PMID: 30270214 PMCID: PMC6941640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/01/2018] [Accepted: 07/23/2018] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The prevalence of type 2 diabetes mellitus (T2DM) is increasing in Iran. This study determined the prevalence of undiagnosed type 2 diabetes mellitus in apparently normal individuals in Hamadan, west of Iran. STUDY DESIGN A cross-sectional study. METHODS A sample of 106 apparently normal volunteers aged 18 yr and more were enrolled, and T2DM was diagnosed using hemoglobin A1c (HbA1c) levels from 2015-2016. The nonparametric bootstrap method was used to eliminate the undesirable effect of small sample size on the estimation of standard error of multiple logistic regression coefficients and confidence interval for the prevalence of undiagnosed T2DM. RESULTS Overall, 23 (21.69%) were male. The mean (±sd) age of the participants was 43.76 ±14.01 year. In 78.3% of individuals, HbA1c level was within normal range (<5.7), 13.21% was in the range of 5.7-6.4 (undiagnosed pre-T2DM), and 8.49% was ≥6.5 (undiagnosed T2DM). Multiple logistic regression gave the characteristic distribution of volunteers such as sedentary hour (P=0.001), family history of diabetes (P=0.001), smoking (P=0.002), and age (P=0.012) had the odds on the significant effect on undiagnosed T2DM. CONCLUSIONS The prevalence of undiagnosed T2DM among apparently normal individuals in Hamadan was relatively high. Addition to age, factors such as sedentary, exposure to smoking and having a history of diabetes in family can be a prognosis for undiagnosed T2DM in apparently normal individuals.
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Naji M, Nekoonam S, Aleyasin A, Arefian E, Mahdian R, Azizi E, Shabani Nashtaei M, Amidi F. Expression of miR-15a, miR-145, and miR-182 in granulosa-lutein cells, follicular fluid, and serum of women with polycystic ovary syndrome (PCOS). Arch Gynecol Obstet 2017; 297:221-231. [PMID: 29071578 DOI: 10.1007/s00404-017-4570-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 10/16/2017] [Indexed: 12/12/2022]
Abstract
PURPOSE Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies that affects women in reproductive age. MicroRNAs (miRNAs) play crucial roles in normal function of female reproductive system and folliculogenesis. Deregulated expression of miRNAs in PCOS condition may be significantly implicated in the pathogenesis of PCOS. We determined relative expression of miR-15a, miR-145, and miR-182 in granulosa-lutein cells (GLCs), follicular fluid (FF), and serum of PCOS patients. METHODS Human subjects were divided into PCOS (n = 20) and control (n = 21) groups. GLCs, FF, and serum were isolated and stored. RNA isolation was performed and cDNA was reversely transcribed using specific stem-loop RT primers. Relative expression of miRNAs was calculated after normalization against U6 expression. Correlation of miRNAs' expression level with basic clinical features and predictive value of miRNAs in FF and serum were appraised. RESULTS Relative expression of miR-145 and miR-182 in GLCs was significantly decreased in PCOS, but miR-182 in FF of PCOS patients revealed up-regulated levels. Significant correlations between level of miRNAs in FF and serum and hormonal profile of subjects were observed. MiR-182 in FF showed a significant predictive value with AUC of 0.73, 76.4% sensitivity, and 70.5% specificity which was improved after combination of miR-182 and miR-145. CONCLUSIONS A significant dysregulation of miR-145 and miR-182 in GLCs of PCOS may indicate their involvement in pathogenesis of PCOS. Differential up-regulation of miR-182 in FF of PCOS patients with its promising predictive values for discrimination of PCOS reinforced the importance of studying miRNAs' profile in FF.
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Inzelberg R, Friedman E, Azizi E. Cutaneous squamous cell carcinoma and the PARK2 gene. Br J Dermatol 2017; 177:323-324. [PMID: 28301044 DOI: 10.1111/bjd.15465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Azizi E, Prabhakaran S, Carr A, Pe'er D. Bayesian Inference for Single-cell Clustering and Imputing. ACTA ACUST UNITED AC 2017. [DOI: 10.18547/gcb.2017.vol3.iss1.e46] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Single-cell RNA-seq gives access to gene expression measurements for thousands of cells, allowing discovery and characterization of cell types. However, the data is noise-prone due to experimental errors and cell type-specific biases. Current computational approaches for analyzing single-cell data involve a global normalization step which introduces incorrect biases and spurious noise and does not resolve missing data (dropouts). This can lead to misleading conclusions in downstream analyses. Moreover, a single normalization removes important cell type-specific information. We propose a data-driven model, BISCUIT, that iteratively normalizes and clusters cells, thereby separating noise from interesting biological signals. BISCUIT is a Bayesian probabilistic model that learns cell-specific parameters to intelligently drive normalization. This approach displays superior performance to global normalization followed by clustering in both synthetic and real single-cell data compared with previous methods, and allows easy interpretation and recovery of the underlying structure and cell types.
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Dekhang R, Wu C, Smith KM, Lamb TM, Peterson M, Bredeweg EL, Ibarra O, Emerson JM, Karunarathna N, Lyubetskaya A, Azizi E, Hurley JM, Dunlap JC, Galagan JE, Freitag M, Sachs MS, Bell-Pedersen D. The Neurospora Transcription Factor ADV-1 Transduces Light Signals and Temporal Information to Control Rhythmic Expression of Genes Involved in Cell Fusion. G3 (BETHESDA, MD.) 2017; 7:129-142. [PMID: 27856696 PMCID: PMC5217103 DOI: 10.1534/g3.116.034298] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/01/2016] [Indexed: 12/20/2022]
Abstract
Light and the circadian clock have a profound effect on the biology of organisms through the regulation of large sets of genes. Toward understanding how light and the circadian clock regulate gene expression, we used genome-wide approaches to identify the direct and indirect targets of the light-responsive and clock-controlled transcription factor ADV-1 in Neurospora crassa A large proportion of ADV-1 targets were found to be light- and/or clock-controlled, and enriched for genes involved in development, metabolism, cell growth, and cell fusion. We show that ADV-1 is necessary for transducing light and/or temporal information to its immediate downstream targets, including controlling rhythms in genes critical to somatic cell fusion. However, while ADV-1 targets are altered in predictable ways in Δadv-1 cells in response to light, this is not always the case for rhythmic target gene expression. These data suggest that a complex regulatory network downstream of ADV-1 functions to generate distinct temporal dynamics of target gene expression relative to the central clock mechanism.
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Rezaee K, Azizi E, Haddadnia J. Optimized Seizure Detection Algorithm: A Fast Approach for Onset of Epileptic in EEG Signals Using GT Discriminant Analysis and K-NN Classifier. J Biomed Phys Eng 2016; 6:81-94. [PMID: 27672628 PMCID: PMC5022758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Indexed: 06/06/2023]
Abstract
BACKGROUND Epilepsy is a severe disorder of the central nervous system that predisposes the person to recurrent seizures. Fifty million people worldwide suffer from epilepsy; after Alzheimer's and stroke, it is the third widespread nervous disorder. OBJECTIVE In this paper, an algorithm to detect the onset of epileptic seizures based on the analysis of brain electrical signals (EEG) has been proposed. 844 hours of EEG were recorded form 23 pediatric patients consecutively with 163 occurrences of seizures. Signals had been collected from Children's Hospital Boston with a sampling frequency of 256 Hz through 18 channels in order to assess epilepsy surgery. By selecting effective features from seizure and non-seizure signals of each individual and putting them into two categories, the proposed algorithm detects the onset of seizures quickly and with high sensitivity. METHOD In this algorithm, L-sec epochs of signals are displayed in form of a third-order tensor in spatial, spectral and temporal spaces by applying wavelet transform. Then, after applying general tensor discriminant analysis (GTDA) on tensors and calculating mapping matrix, feature vectors are extracted. GTDA increases the sensitivity of the algorithm by storing data without deleting them. Finally, K-Nearest neighbors (KNN) is used to classify the selected features. RESULTS The results of simulating algorithm on algorithm standard dataset shows that the algorithm is capable of detecting 98 percent of seizures with an average delay of 4.7 seconds and the average error rate detection of three errors in 24 hours. CONCLUSION Today, the lack of an automated system to detect or predict the seizure onset is strongly felt.
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Holt NC, Azizi E. The effect of activation level on muscle function during locomotion: are optimal lengths and velocities always used? Proc Biol Sci 2016; 283:rspb.2015.2832. [PMID: 26817770 DOI: 10.1098/rspb.2015.2832] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/04/2016] [Indexed: 11/12/2022] Open
Abstract
Skeletal muscle exhibits broad functional diversity, despite its inherent length and velocity constraints. The observed variation in morphology and physiology is assumed to have evolved to allow muscle to operate at its optimal length and velocity during locomotion. Here, we used the variation in optimum lengths and velocities that occurs with muscle activation level to experimentally test this assumption. Muscle ergometry and sonomicrometry were used to characterize force-length and power-velocity relationships, and in vivo operating lengths and velocities, at a range of activation levels. Operating lengths and velocities were mapped onto activation level specific force-length and power-velocity relationships to determine whether they tracked changing optima. Operating velocities decreased in line with decreased optimal velocities, suggesting that optimal velocities are always used. However, operating lengths did not change with changing optima. At high activation levels, fibres used an optimal range of lengths. However, at lower activation levels, fibres appeared to operate on the ascending limb of sub-maximally activated force-length relationships. This suggests that optimal lengths are only used when demand is greatest. This study provides the first mapping of operating lengths to activation level-specific optima, and as such, provides insight into our assumptions about the factors that determine muscle performance during locomotion.
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Prabhakaran S, Azizi E, Carr A, Pe'er D. Dirichlet Process Mixture Model for Correcting Technical Variation in Single-Cell Gene Expression Data. JMLR WORKSHOP AND CONFERENCE PROCEEDINGS 2016; 48:1070-1079. [PMID: 29928470 PMCID: PMC6004614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We introduce an iterative normalization and clustering method for single-cell gene expression data. The emerging technology of single-cell RNA-seq gives access to gene expression measurements for thousands of cells, allowing discovery and characterization of cell types. However, the data is confounded by technical variation emanating from experimental errors and cell type-specific biases. Current approaches perform a global normalization prior to analyzing biological signals, which does not resolve missing data or variation dependent on latent cell types. Our model is formulated as a hierarchical Bayesian mixture model with cell-specific scalings that aid the iterative normalization and clustering of cells, teasing apart technical variation from biological signals. We demonstrate that this approach is superior to global normalization followed by clustering. We show identifiability and weak convergence guarantees of our method and present a scalable Gibbs inference algorithm. This method improves cluster inference in both synthetic and real single-cell data compared with previous methods, and allows easy interpretation and recovery of the underlying structure and cell types.
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Holt NC, Azizi E. What drives activation-dependent shifts in the force-length curve? Biol Lett 2015; 10:rsbl.2014.0651. [PMID: 25252838 DOI: 10.1098/rsbl.2014.0651] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Skeletal muscles are rarely recruited maximally during movement. However, much of our understanding of muscle properties is based on studies using maximal activation. The effect of activation level on skeletal muscle properties remains poorly understood. Muscle optimum length increases with decreased activation; however, the mechanism responsible is unclear. Here, we attempted to determine whether length-dependent calcium effects, or the effect of absolute force underpin this shift. Fixed-end contractions were performed in frog plantaris muscles at a range of lengths using maximal tetanic (high force, high calcium), submaximal tetanic (low force, high calcium) and twitch (low force, low calcium) stimulation conditions. Peak force and optimum length were determined in each condition. Optimum length increased with decreasing peak force, irrespective of stimulation condition. Assuming calcium concentration varied as predicted, this suggests that absolute force, rather than calcium concentration, underpins the effect of activation level on optimum length. We suggest that the effect of absolute force is due to the varying effect of the internal mechanics of the muscle at different activation levels. These findings have implications for our understanding of in vivo muscle function and suggest that mechanical interactions within muscle may be important determinants of force at lower levels of activation.
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Azizi E, Deslauriers AR. Regional heterogeneity in muscle fiber strain: the role of fiber architecture. Front Physiol 2014; 5:303. [PMID: 25161626 PMCID: PMC4129366 DOI: 10.3389/fphys.2014.00303] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/25/2014] [Indexed: 11/13/2022] Open
Abstract
The force, mechanical work and power produced by muscle fibers are profoundly affected by the length changes they undergo during a contraction. These length changes are in turn affected by the spatial orientation of muscle fibers within a muscle (fiber architecture). Therefore any heterogeneity in fiber architecture within a single muscle has the potential to cause spatial variation in fiber strain. Here we examine how the architectural variation within a pennate muscle and within a fusiform muscle can result in regional fiber strain heterogeneity. We combine simple geometric models with empirical measures of fiber strain to better understand the effect of architecture on fiber strain heterogeneity. We show that variation in pennation angle throughout a muscle can result in differences in fiber strain with higher strains being observed at lower angles of pennation. We also show that in fusiform muscles, the outer/superficial fibers of the muscle experience lower strains than central fibers. These results show that regional variation in mechanical output of muscle fibers can arise solely from architectural features of the muscle without the presence of any spatial variation in motor recruitment.
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Gomes ALC, Abeel T, Peterson M, Azizi E, Lyubetskaya A, Carvalho L, Galagan J. Decoding ChIP-seq with a double-binding signal refines binding peaks to single-nucleotides and predicts cooperative interaction. Genome Res 2014; 24:1686-97. [PMID: 25024162 PMCID: PMC4199365 DOI: 10.1101/gr.161711.113] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The comprehension of protein and DNA binding in vivo is essential to understand gene regulation. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) provides a global map of the regulatory binding network. Most ChIP-seq analysis tools focus on identifying binding regions from coverage enrichment. However, less work has been performed to infer the physical and regulatory details inside the enriched regions. This research extends a previous blind-deconvolution approach to develop a post-peak-calling algorithm that improves binding site resolution and predicts cooperative interactions. At the core of our new method is a physically motivated model that characterizes the binding signal as an extreme value distribution. This model suggests a mathematical framework to study physical properties of DNA shearing from the ChIP-seq coverage. The model explains the ChIP-seq coverage with two signals: The first considers DNA fragments with only a single binding event, whereas the second considers fragments with two binding events (a double-binding signal). The model incorporates motif discovery and is able to detect multiple sites in an enriched region with single-nucleotide resolution, high sensitivity, and high specificity. Our method improves peak caller sensitivity, from less than 45% up to 94%, at a false positive rate < 11% for a set of 47 experimentally validated prokaryotic sites. It also improves resolution of highly enriched regions of large-scale eukaryotic data sets. The double-binding signal provides a novel application in ChIP-seq analysis: the identification of cooperative interaction. Predictions of known cooperative binding sites show a 0.85 area under an ROC curve.
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Astley HC, Abbott EM, Azizi E, Marsh RL, Roberts TJ. Chasing maximal performance: a cautionary tale from the celebrated jumping frogs of Calaveras County. ACTA ACUST UNITED AC 2014; 216:3947-53. [PMID: 24133149 DOI: 10.1242/jeb.090357] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Maximal performance is an essential metric for understanding many aspects of an organism's biology, but it can be difficult to determine because a measured maximum may reflect only a peak level of effort, not a physiological limit. We used a unique opportunity provided by a frog jumping contest to evaluate the validity of existing laboratory estimates of maximum jumping performance in bullfrogs (Rana catesbeiana). We recorded video of 3124 bullfrog jumps over the course of the 4-day contest at the Calaveras County Jumping Frog Jubilee, and determined jump distance from these images and a calibration of the jump arena. Frogs were divided into two groups: 'rental' frogs collected by fair organizers and jumped by the general public, and frogs collected and jumped by experienced, 'professional' teams. A total of 58% of recorded jumps surpassed the maximum jump distance in the literature (1.295 m), and the longest jump was 2.2 m. Compared with rental frogs, professionally jumped frogs jumped farther, and the distribution of jump distances for this group was skewed towards long jumps. Calculated muscular work, historical records and the skewed distribution of jump distances all suggest that the longest jumps represent the true performance limit for this species. Using resampling, we estimated the probability of observing a given jump distance for various sample sizes, showing that large sample sizes are required to detect rare maximal jumps. These results show the importance of sample size, animal motivation and physiological conditions for accurate maximal performance estimates.
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Gillis G, Ekstrom L, Azizi E. Biomechanics and Control of Landing in Toads. Integr Comp Biol 2014; 54:1136-47. [DOI: 10.1093/icb/icu053] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Azizi E. Locomotor function shapes the passive mechanical properties and operating lengths of muscle. Proc Biol Sci 2014; 281:20132914. [PMID: 24718759 DOI: 10.1098/rspb.2013.2914] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Locomotor muscles often perform diverse roles, functioning as motors that produce mechanical energy, struts that produce force and brakes that dissipate mechanical energy. In many vertebrate muscles, these functions are not mutually exclusive and a single muscle often performs a range of mechanically diverse tasks. This functional diversity has obscured the relationship between a muscle's locomotor function and its mechanical properties. I use hopping in toads as a model system for comparing muscles that primarily produce mechanical energy with muscles that primarily dissipate mechanical energy. During hopping, hindlimb muscles undergo active shortening to produce mechanical energy and propel the animal into the air, whereas the forelimb muscles undergo active lengthening to dissipate mechanical energy during landing. Muscles performing distinct mechanical functions operate on different regions of the force-length curve. These findings suggest that a muscle's operating length may be shaped by potential trade-offs between force production and sarcomere stability. In addition, the passive force-length properties of hindlimb and forelimb muscles vary, suggesting that passive stiffness functions to restrict the muscle's operating length in vivo. These results inform our understanding of vertebrate muscle variation by providing a clear link between a muscle's locomotor function and its mechanical properties.
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Etemad-Moghadam S, Fouladdel S, Azizi E, Alaeddini M. In vitro study on the effect of doxorubicin on the proliferation markers MCM3 and Ki-67. JOURNAL OF B.U.ON. : OFFICIAL JOURNAL OF THE BALKAN UNION OF ONCOLOGY 2013; 18:1062-1068. [PMID: 24344040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
PURPOSE Aberrant proliferation is an essential feature of cancer cells, which can be caused by alterations in components of the cell cycle, such as minichromosome maintenance protein-3 (MCM3) and Ki-67. Doxorubicin is a cytotoxic/cytostatic anticancer agent commonly used in chemotherapy. We investigated the effect of this drug on MCM3 and Ki-67 in the KB cell line, which is considered a subline of HeLa cell line. METHODS KB cells were treated with doxorubicin and its effect on apoptosis, mRNA levels and protein expression of MCM3 and Ki-67 was determined by flow cytometry (annexin V-FITC/PI assay), quantitative real-time RT-PCR (qRT-PCR) and immunocytochemistry, respectively. Cytotoxicity was assessed using the MTT assay. One-way analysis of variance (ANOVA) was used for comparing groups and differences were assessed by a Tukey's post hoc test. RESULTS Protein expression of both biomarkers and MCM3 mRNA were not affected by doxorubicin, but Ki-67 mRNA significantly increased after treatment (p=0.049). CONCLUSIONS Considering that doxorubicin can influence certain biochemical events that lead to modifications in Ki- 67, this factor might be useful in evaluating the impact of anthracycline-based chemotherapeutic agents. Changes in MCM3 following doxorubicin treatment require further investigation.
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Karami-Mohajeri S, Hadian MR, Fouladdel S, Azizi E, Ghahramani MH, Hosseini R, Abdollahi M. Mechanisms of muscular electrophysiological and mitochondrial dysfunction following exposure to malathion, an organophosphorus pesticide. Hum Exp Toxicol 2013; 33:251-63. [PMID: 23774768 DOI: 10.1177/0960327113493300] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Muscle dysfunction in acute organophosphorus (OP) poisoning is a cause of death in human. The present study was conducted to identify the mechanism of action of OP in terms of muscle mitochondrial dysfunction. Electromyography (EMG) was conducted on rats exposed to the acute oral dose of malathion (400 mg/kg) that could inhibit acetylcholinesterase activity up to 70%. The function of mitochondrial respiratory chain and the rate of production of reactive oxygen species (ROS) from intact mitochondria were measured. The bioenergetic pathways were studied by measurement of adenosine triphosphate (ATP), lactate, and glycogen. To identify mitochondrial-dependent apoptotic pathways, the messenger RNA (mRNA) expression of bax and bcl-2, protein expression of caspase-9, mitochondrial cytochrome c release, and DNA damage were measured. The EMG confirmed muscle weakness. The reduction in activity of mitochondrial complexes and muscular glycogen with an elevation of lactate was in association with impairment of cellular respiration. The reduction in mitochondrial proapoptotic stimuli is indicative of autophagic process inducing cytoprotective effects in the early stage of stress. Downregulation of apoptotic signaling may be due to reduction in ATP and ROS, and genotoxic potential of malathion. The maintenance of mitochondrial integrity by means of artificial electron donors and increasing exogenous ATP might prevent toxicity of OPs.
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Rezvan F, Khabazkhoob M, Fotouhi A, Hashemi H, Ostadimoghaddam H, Heravian J, Azizi E, Khorasani AA, Yekta AA. Prevalence of refractive errors among school children in Northeastern Iran. Ophthalmic Physiol Opt 2011; 32:25-30. [DOI: 10.1111/j.1475-1313.2011.00879.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Dalili D, Fouladdel S, Rastkari N, Samadi N, Ahmadkhaniha R, Ardavan A, Azizi E. Prodigiosin, the red pigment of Serratia marcescens, shows cytotoxic effects and apoptosis induction in HT-29 and T47D cancer cell lines. Nat Prod Res 2011; 26:2078-83. [PMID: 21985476 DOI: 10.1080/14786419.2011.622276] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In this study, a red pigment of Serratia marcescens PTCC 1111 was purified and identified for antiproliferative activities in HT-29 and T47D cancer cell lines. (1)H-NMR spectroscopy and LC/MS analysis confirmed prodigiosin structure. The antiproliferative effects of prodigiosin were determined by employing the MTT assay. The changes in cell cycle pattern were studied with 4',6-diamidino-2-phenylindole (DAPI) reagent using flow cytometry assay, and Annexin V-PI method was used for apoptotic analysis. Results of MTT assay showed that HT-29 cells were more sensitive to prodigiosin than T47D cells. Prodigiosin-treated HT-29 cells showed increase in S phase and decrease in G2/M, but treated T47D cells showed cell cycle pattern relatively similar to Roswell Park Memorial Institute medium (RPMI). Apoptotic effect of prodigiosin was higher than doxorubicin in HT-29 cells. The data reported here indicate that prodigiosin is a promising antineoplastic agent that triggers apoptosis in different cancer cell lines.
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Rezaei PF, Fouladdel S, Cristofanon S, Ghaffari SM, Amin GR, Azizi E. Comparative cellular and molecular analysis of cytotoxicity and apoptosis induction by doxorubicin and Baneh in human breast cancer T47D cells. Cytotechnology 2011; 63:503-12. [PMID: 21818667 DOI: 10.1007/s10616-011-9373-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 06/21/2011] [Indexed: 12/21/2022] Open
Abstract
It is now widely accepted that dietary phytochemicals inhibit cancer progression and enhance the effects of conventional chemotherapy. In this report, we comparatively studied the cellular and molecular aspects of apoptosis induction by the methanolic extract of Baneh fruit skin in comparison to Doxorubicin (Dox), a well-known anticancer drug, in human breast cancer T47D cells. The MTT assay was used to determine the antiproliferative effects. The flow cytometric and microscopic analyses were done to evaluate the apoptosis induction. Furthermore, western blot analyses have been done to study the role of key molecular players of apoptosis including caspase 3 and PARP. The Baneh extract showed strong antiproliferative activity against T47D cells in a dose- and time-dependent manner that was comparable to and even stronger than Dox in certain concentrations. Analysis of Baneh-treated cells by flow cytometry and fluorescence microscopy indicated strong apoptosis induction and nuclear morphological alterations similar to or greater than Dox. Finally, molecular analysis of apoptosis by western blotting proved activation of caspase 3 followed by poly ADP ribose polymerase (PARP) cleavage more efficiently in Baneh than in Dox treated cancer cells. These findings indicate that Baneh extract contains phytochemicals which act as inhibitor of cell proliferation and inducer of apoptosis in human breast cancer T47D cells that makes it a potentially good candidate for new anticancer drug development.
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