Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 60
Filter
1.
Circulation ; 148(15): 1165-1178, 2023 10 10.
Article in English | MEDLINE | ID: mdl-37681311

ABSTRACT

BACKGROUND: Clonal hematopoiesis (CH), which results from an array of nonmalignant driver gene mutations, can lead to altered immune cell function and chronic disease, and has been associated with worse outcomes in patients with heart failure (HF) with reduced ejection fraction. However, the role of CH in the prognosis of HF with preserved ejection fraction (HFpEF) has been understudied. This study aimed to characterize CH in patients with HFpEF and elucidate its causal role in a murine model. METHODS: Using a panel of 20 candidate CH driver genes and a variant allele fraction cutoff of 0.5%, ultradeep error-corrected sequencing identified CH in a cohort of 81 patients with HFpEF (mean age, 71±6 years; ejection fraction, 63±5%) and 36 controls without a diagnosis of HFpEF (mean age, 74±7 years; ejection fraction, 61.5±8%). CH was also evaluated in a replication cohort of 59 individuals with HFpEF. RESULTS: Compared with controls, there was an enrichment of TET2-mediated CH in the HFpEF patient cohort (12% versus 0%, respectively; P=0.02). In the HFpEF cohort, patients with CH exhibited exacerbated diastolic dysfunction in terms of E/e' (14.9 versus 11.7, respectively; P=0.0096) and E/A (1.69 versus 0.89, respectively; P=0.0206) compared with those without CH. The association of CH with exacerbated diastolic dysfunction was corroborated in a validation cohort of individuals with HFpEF. In accordance, patients with HFpEF, an age ≥70 years, and CH exhibited worse prognosis in terms of 5-year cardiovascular-related hospitalization rate (hazard ratio, 5.06; P=0.042) compared with patients with HFpEF and an age ≥70 years without CH. To investigate the causal role of CH in HFpEF, nonconditioned mice underwent adoptive transfer with Tet2-wild-type or Tet2-deficient bone marrow and were subsequently subjected to a high-fat diet/L-NAME (Nω-nitro-l-arginine methyl ester) combination treatment to induce features of HFpEF. This model of Tet2-CH exacerbated cardiac hypertrophy by heart weight/tibia length and cardiomyocyte size, diastolic dysfunction by E/e' and left ventricular end-diastolic pressure, and cardiac fibrosis compared with the Tet2-wild-type condition. CONCLUSIONS: CH is associated with worse heart function and prognosis in patients with HFpEF, and a murine experimental model of Tet2-mediated CH displays greater features of HFpEF.


Subject(s)
Heart Failure , Ventricular Dysfunction, Left , Humans , Mice , Animals , Aged , Aged, 80 and over , Heart Failure/diagnosis , Heart Failure/genetics , Heart Failure/drug therapy , Stroke Volume , Ventricular Function, Left , Clonal Hematopoiesis/genetics , Ventricular Dysfunction, Left/genetics
3.
Int J Mol Sci ; 23(17)2022 Aug 23.
Article in English | MEDLINE | ID: mdl-36076915

ABSTRACT

Streptococcus pyogenes, or group A Streptococcus (GAS), a gram-positive bacterium, is implicated in a wide range of clinical manifestations and life-threatening diseases. One of the key virulence factors of GAS is streptopain, a C10 family cysteine peptidase. Since its discovery, various homologs of streptopain have been reported from other bacterial species. With the increased affordability of sequencing, a significant increase in the number of potential C10 family-like sequences in the public databases is anticipated, posing a challenge in classifying such sequences. Sequence-similarity-based tools are the methods of choice to identify such streptopain-like sequences. However, these methods depend on some level of sequence similarity between the existing C10 family and the target sequences. Therefore, in this work, we propose a novel predictor, C10Pred, for the prediction of C10 peptidases using sequence-derived optimal features. C10Pred is a support vector machine (SVM) based model which is efficient in predicting C10 enzymes with an overall accuracy of 92.7% and Matthews' correlation coefficient (MCC) value of 0.855 when tested on an independent dataset. We anticipate that C10Pred will serve as a handy tool to classify novel streptopain-like proteins belonging to the C10 family and offer essential information.


Subject(s)
Cysteine Proteases , Cysteine , Machine Learning , Proteins , Support Vector Machine
4.
Genomics Inform ; 18(1): e6, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32224839

ABSTRACT

Acute leukemia represents the most common pediatric malignancy comprising diverse subtypes with varying prognosis and treatment outcomes. New and targeted treatment options are warranted for this disease. Patient-derived xenograft (PDX) models are increasingly being used for preclinical testing of novel treatment modalities. A novel approach involving targeted error-corrected RNA sequencing using ArcherDX HemeV2 kit was employed to compare 25 primary pediatric acute leukemia samples and their corresponding PDX samples. A comparison of the primary samples and PDX samples revealed a high concordance between single nucleotide variants and gene fusions whereas other complex structural variants were not as consistent. The presence of gene fusions representing the major driver mutations at similar allelic frequencies in PDX samples compared to primary samples and over multiple passages confirms the utility of PDX models for preclinical drug testing. Characterization and tracking of these novel cryptic fusions and exonal variants in PDX models is critical in assessing response to potential new therapies.

5.
BMC Med Genomics ; 13(1): 32, 2020 03 04.
Article in English | MEDLINE | ID: mdl-32131829

ABSTRACT

BACKGROUND: Pediatric leukemias have a diverse genomic landscape associated with complex structural variants, including gene fusions, insertions and deletions, and single nucleotide variants. Routine karyotype and fluorescence in situ hybridization (FISH) techniques lack sensitivity for smaller genomic alternations. Next-generation sequencing (NGS) assays are being increasingly utilized for assessment of these various lesions. However, standard NGS lacks quantitative sensitivity for minimal residual disease (MRD) surveillance due to an inherently high error rate. METHODS: Primary bone marrow samples from pediatric leukemia (n = 32) and adult leukemia subjects (n = 5), cell line MV4-11, and an umbilical cord sample were utilized for this study. Samples were sequenced using molecular barcoding with targeted DNA and RNA library enrichment techniques based on anchored multiplexed PCR (AMP®) technology, amplicon based error-corrected sequencing (ECS) or a human cancer transcriptome assay. Computational analyses were performed to quantitatively assess limit of detection (LOD) for various DNA and RNA lesions, which could be systematically used for MRD assays. RESULTS: Matched leukemia patient samples were analyzed at three time points; diagnosis, end of induction (EOI), and relapse. Similar to flow cytometry for ALL MRD, the LOD for point mutations by these sequencing strategies was ≥0.001. For DNA structural variants, FLT3 internal tandem duplication (ITD) positive cell line and patient samples showed a LOD of ≥0.001 in addition to previously unknown copy number losses in leukemia genes. ECS in RNA identified multiple novel gene fusions, including a SPANT-ABL gene fusion in an ALL patient, which could have been used to alter therapy. Collectively, ECS for RNA demonstrated a quantitative and complex landscape of RNA molecules with 12% of the molecules representing gene fusions, 12% exon duplications, 8% exon deletions, and 68% with retained introns. Droplet digital PCR validation of ECS-RNA confirmed results to single mRNA molecule quantities. CONCLUSIONS: Collectively, these assays enable a highly sensitive, comprehensive, and simultaneous analysis of various clonal leukemic mutations, which can be tracked across disease states (diagnosis, EOI, and relapse) with a high degree of sensitivity. The approaches and results presented here highlight the ability to use NGS for MRD tracking.


Subject(s)
High-Throughput Nucleotide Sequencing , Leukemia/diagnosis , Leukemia/genetics , Mutation , Adolescent , Cell Line, Tumor , Child , Female , Humans , Leukemia/therapy , Male , Neoplasm, Residual
6.
Sci Transl Med ; 12(526)2020 01 15.
Article in English | MEDLINE | ID: mdl-31941826

ABSTRACT

Clonal hematopoiesis is associated with various age-related morbidities. Error-corrected sequencing (ECS) of human blood samples, with a limit of detection of ≥0.0001, has demonstrated that nearly every healthy individual >50 years old harbors rare hematopoietic clones below the detection limit of standard high-throughput sequencing. If these rare mutations confer survival or proliferation advantages, then the clone(s) could expand after a selective pressure such as chemotherapy, radiotherapy, or chronic immunosuppression. Given these observations and the lack of quantitative data regarding clonal hematopoiesis in adolescents and young adults, who are more likely to serve as unrelated hematopoietic stem cell donors, we completed this pilot study to determine whether younger adults harbored hematopoietic clones with pathogenic mutations, how often those clones were transferred to recipients, and what happened to these clones over time after transplantation. We performed ECS on 125 blood and marrow samples from 25 matched unrelated donors and recipients. Clonal mutations, with a median variant allele frequency of 0.00247, were found in 11 donors (44%; median, 36 years old). Of the mutated clones, 84.2% of mutations were predicted to be molecularly pathogenic and 100% engrafted in recipients. Recipients also demonstrated de novo clonal expansion within the first 100 days after hematopoietic stem cell transplant (HSCT). Given this pilot demonstration that rare, pathogenic clonal mutations are far more prevalent in younger adults than previously appreciated, and they engraft in recipients and persist over time, larger studies with longer follow-up are necessary to correlate clonal engraftment with post-HSCT morbidity.


Subject(s)
Hematopoietic Stem Cell Transplantation/methods , Mutation/genetics , Adult , Female , Graft vs Host Disease , Humans , Male , Middle Aged , Mutation, Missense , Pilot Projects
7.
FASEB J ; 33(5): 6354-6364, 2019 05.
Article in English | MEDLINE | ID: mdl-30786218

ABSTRACT

A central question in cell biology is how cells respond to stress signals and biochemically regulate apoptosis. One critical pathway involves the change of mitochondrial function and release of cytochrome c to initiate apoptosis. In response to apoptotic stimuli, we found that maspin-a noninhibitory member of the serine protease inhibitor superfamily-translocates from the cytosol to mitochondria and binds to cardiolipin in the inner mitochondrial membrane. Biolayer interferometry assay revealed that recombinant maspin binds cardiolipin with an apparent Kd,of ∼15.8 µM and competes with cytochrome c (apparent Kd of ∼1.31 µM) for binding to cardiolipin-enriched membranes. A hydrophobic, lysine-rich domain in maspin consists of 27 aa, is located at position 268-294, and is responsible for the interaction of this protein with cardiolipin. Depletion of cardiolipin in cells significantly prevents maspin binding to the inner mitochondrial membrane and decreases cytochrome c release and apoptosis. Alteration to maspin's cardiolipin binding domain changes its ability to bind cardiolipin, and tumor cells expressing this mutant have a low frequency of apoptosis. We propose a model of apoptosis in which maspin binds to cardiolipin, displaces cytochrome c from the membrane, and facilitates its release to the cytoplasm.-Mahajan, N., Hoover, B., Rajendram, M., Shi, H. Y., Kawasaki, K., Weibel, D. B., Zhang, M. Maspin binds to cardiolipin in mitochondria and triggers apoptosis.


Subject(s)
Apoptosis , Cardiolipins/metabolism , Mitochondria/metabolism , Mitochondrial Membranes/metabolism , Serpins/metabolism , Animals , CHO Cells , Cardiolipins/genetics , Cricetulus , Cytochromes c/genetics , Cytochromes c/metabolism , Mice , Mitochondria/genetics , Protein Binding , Serpins/genetics
8.
FASEB Bioadv ; 1(7): 404-414, 2019 Jul.
Article in English | MEDLINE | ID: mdl-32095781

ABSTRACT

The orphan small nucleolar RNA (snoRNA) ACA11 is overexpressed as a result of the t(4;14) chromosomal translocation in multiple myeloma (MM), increases reactive oxygen species, and drives cell proliferation. Like other snoRNAs, ACA11 is predominantly localized to a sub-nuclear organelle, the nucleolus. We hypothesized that increased ACA11 expression would increase ribosome biogenesis and protein synthesis. We found that ACA11 overexpression in MM cells increased nucleolar area and number as well as silver-binding nucleolar organizing regions (AgNORs). Supporting these data, samples from t(4;14)-positive patients had higher AgNORs scores than t(4;14)-negative samples. ACA11 also upregulated ribosome production, pre-47S rRNA synthesis, and protein synthesis in a ROS-dependent manner. Lastly, ACA11 overexpression enhanced the response to proteasome inhibitor in MM cells, while no effect was found in response to high doses of melphalan. Together, these data demonstrate that ACA11 stimulates ribosome biogenesis and influences responses to chemotherapy. ACA11 may be a useful target to individualize the treatment for t(4;14)-positive myeloma patients.

9.
Glob Heart ; 13(4): 267-274.e2, 2018 12.
Article in English | MEDLINE | ID: mdl-30197242

ABSTRACT

BACKGROUND: Despite the high prevalence of rheumatic heart disease (RHD) in developing countries such as India, data on characteristics, complications, and treatment practices are lacking. The HP-RHD (Himachal Pradesh Rheumatic Heart Disease) registry aimed at reporting these parameters in patients with RHD from a northern state of India. METHODS: A total of 2,005 consecutive patients of RHD were enrolled over a period of 6 years (2011 to 2016) in the present study. The clinical characteristics, complications, and treatment practices were systematically recorded. RESULTS: The mean age for patients with RHD was 40.3 ± 14.3 (range 5 to 83 years). RHD predominantly affected females (72.3%) and population from rural background (92%). Multivalvular involvement was frequent (43.2%), mitral valve was the commonest affected valve (83.3%). The majority of the patients had moderate-to-severe valvular dysfunction (69.3%). Mitral and tricuspid valve involvement was more frequent in female subjects compared with more frequent aortic valve involvement in male subjects (p < 0.001). The major adverse cardiovascular events were recorded in 23.4% patients at the time of registry and comprised mainly advanced heart failure (15.6%), peripheral embolism (4.1%), and stroke (3.9%). The independent risk determinants of major adverse cardiovascular events (were advanced age (odds ratio [OR]: 1.01; 95% confidence interval [CI]: 1.00-1.02), severe mitral stenosis (OR: 1.73; 95% CI: 1.34-2.20), severe tricuspid regurgitation (OR: 2.11; 95% CI: 1.48-3.02), presence of pulmonary artery hypertension (OR: 1.33; 95% CI: 1.04-1.69), and atrial fibrillation (OR: 1.64; 95% CI: 1.28-2.11). Evidence-based use of oral anticoagulant therapy was documented in 77.7% of high-risk patients. Only 28.5% of study population was receiving secondary prophylaxis. CONCLUSIONS: Complications in patients with RHD increase with age and worsening valvular dysfunction. Programs focused on early detection and evidence-based management will assist in improving outcomes.


Subject(s)
Antirheumatic Agents/therapeutic use , Heart Valve Diseases/prevention & control , Registries , Rheumatic Heart Disease/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Follow-Up Studies , Heart Valve Diseases/epidemiology , Heart Valve Diseases/etiology , Humans , India/epidemiology , Middle Aged , Prevalence , Prognosis , Prospective Studies , Rheumatic Heart Disease/complications , Rheumatic Heart Disease/therapy , Time Factors , Young Adult
11.
Int J Cardiol ; 248: 1-6, 2017 Dec 01.
Article in English | MEDLINE | ID: mdl-28942868

ABSTRACT

INTRODUCTION: Data from high-income countries suggest that women receive less intensive diagnostic and therapeutic management than men for acute coronary syndrome (ACS). There is a paucity of such data in the Indian population, which is 69% rural and prior studies focused mostly on urban populations. The objective of the present study was to identify the gender based differences in ACS management, if any, in a predominantly rural population. METHODS: Data from 35 hospitals across Himachal Pradesh covering >90% of state population were collected for one year (July 2015-June 2016). A total of 2118 ACS subjects met inclusion criteria and baseline characteristics, in-hospital treatments and mortality rates were analyzed. RESULTS: Women constituted less than one-third of ACS population. Women were older compared to men and were more likely to present with NSTEMI/UA. Misinterpretation of initial symptoms and late presentation were also common in women. Fewer women received optimal guideline based treatment and PCI (0.9% vs 4.2%, p<0.01). Compare to men, women more often had Killip class >1 (27.3% vs 20.4%, p<0.01) and higher in-hospital mortality (8.5% vs 5.6%, p=0.009). On multivariate analysis the association between female gender and mortality was attenuated (adjusted odds ratio [OR]=1.36 [0.77-2.38]). CONCLUSION: The present study from India, is the first of its kind to evaluate the gender based differences among ACS patients, in a predominantly rural population. Our analysis demonstrates a significant gender based difference between symptom awareness and delay in presentation, management and in-hospital outcome. Further studies are warranted across other parts of country to investigate this gender disparity.


Subject(s)
Acute Coronary Syndrome/diagnosis , Acute Coronary Syndrome/therapy , Disease Management , Hospitalization/trends , Registries/standards , Acute Coronary Syndrome/epidemiology , Aged , Female , Humans , India/epidemiology , Male , Middle Aged , Retrospective Studies , Rural Population/trends , Sex Factors
12.
J Oral Biol Craniofac Res ; 7(2): 127-133, 2017.
Article in English | MEDLINE | ID: mdl-28706788

ABSTRACT

AIM: The aim is to review the English literature for post-traumatic superolateral dislocation of mandibular condyle (SDMC),discuss their dynamics and clinical management and to propose to modify the existing classification of SDMC. PATIENTS AND METHODS: A literature search was carried at Pubmed, Sciencedirect, Google and references from reported articles were crosschecked to look for the cases of SDMC from 1969 to 2015 in English language. Also, we have reviewed 11 of our patients with total of 18 superolateral dislocated intact or sagittal split condyles ,who visited our unit in the previous two years. RESULTS: In our retrospective analysis 58 cases of SDMC were found in the literature, of which 38 had intact mandibular condyles and 20 had sagittal split. Early and intact SDMC were successfully managed conservatively with closed reduction, whereas old cases and largely fractured condyles necessitated open reduction. Additionally, we observed an unusual dislocation associated with fracture of contralateral posterior mandible(angle) in our series which did not gratify the existing classification. CONCLUSION: Alteration of the existing classification was required to accommodate the unusual type of dislocation.

13.
Am J Cardiol ; 120(2): 304-308, 2017 Jul 15.
Article in English | MEDLINE | ID: mdl-28550931

ABSTRACT

Existing metrics for grading mitral regurgitation (MR) are limited and fraught with high interobserver variability. We developed and evaluated a Doppler-based, semiquantitative novel index (Mitral Regurgitation Severity Index [MRSI]) of MR severity. In a total of 125 patients (70 in the derivation cohort and 55 in the validation cohort), MRSI was calculated as a ratio of time velocity integral of mitral inflow (continuous-wave Doppler-TVI MV) to the time velocity integral of the left ventricle outflow (pulse-wave Doppler-TVI LVOT). Inter-rater agreement for MRSI and predictive ability of the MRSI were then assessed. In the derivation cohort, MRSI differed significantly between patients with severe MR (2.6 ± 0.51) and mild-moderate (nonsevere) MR (1.4 ± 0.18) and a cutoff of ≥1.8 was associated with optimal diagnostic accuracy. In the validation cohort, MRSI exhibited excellent agreement between a level II and a level III reader with a mean difference of -0.14 (95% confidence limit of agreement: -0.80 to 0.53), correlation coefficient of 0.88 (p <0.001), and 16% CV; and using the cut point of 1.8, it exhibited good inter-rater reproducibility with a kappa coefficient of 0.72 (p <0.001). In conclusion, MRSI appears to be a simple, quantitative, practical, color-independent metric to differentiate severe MR from nonsevere MR.


Subject(s)
Blood Flow Velocity/physiology , Echocardiography, Doppler, Color/methods , Echocardiography, Transesophageal/methods , Mitral Valve Insufficiency/diagnosis , Mitral Valve/diagnostic imaging , Chronic Disease , Female , Follow-Up Studies , Humans , Male , Middle Aged , Mitral Valve Insufficiency/physiopathology , Predictive Value of Tests , ROC Curve , Reproducibility of Results , Retrospective Studies , Severity of Illness Index
14.
FASEB J ; 31(2): 482-490, 2017 02.
Article in English | MEDLINE | ID: mdl-28148777

ABSTRACT

Overexpression of the multiple myeloma set domain (MMSET) Wolf-Hirschhorn syndrome candidate 1 gene, which contains an orphan box H/ACA class small nucleolar RNA, ACA11, in an intron, is associated with several cancer types, including multiple myeloma (MM). ACA11 and MMSET are overexpressed cotranscriptionally as a result of the t(4;14) chromosomal translocation in a subset of patients with MM. RNA sequencing of CD138+ tumor cells from t(4;14)-positive and -negative MM patient bone marrow samples revealed an enhanced oxidative phosphorylation mRNA signature. Supporting these data, ACA11 overexpression in a t(4;14)-negative MM cell line, MM1.S, demonstrated enhanced reactive oxygen species (ROS) levels. In addition, an enhancement of cell proliferation, increased soft agar colony size, and elevated ERK1/2 phosphorylation were observed. This ACA11-driven hyperproliferative phenotype depended on increased ROS levels as exogenously added antioxidants attenuate the increased proliferation. A major transcriptional regulator of the cellular antioxidant response, nuclear factor (erythroid-derived 2)-like 2 (NRF2), shuttled to the nucleus, as expected, in response to ACA11-driven increases in ROS; however, transcriptional up-regulation of some of NRF2's antioxidant target genes was abrogated in the presence of ACA11 overexpression. These data show for the first time that ACA11 promotes proliferation through inhibition of NRF2 function resulting in sustained ROS levels driving cancer cell proliferation.-Mahajan, N., Wu, H.-J., Bennett, R. L., Troche, C., Licht, J. D., Weber, J. D., Maggi, L. B., Jr., Tomasson, M. H. Sabotaging of the oxidative stress response by an oncogenic noncoding RNA.


Subject(s)
Fibroblasts/physiology , Gene Expression Regulation/physiology , Oncogenes/physiology , RNA, Untranslated/metabolism , Animals , Cell Line, Tumor , Cell Proliferation , Cells, Cultured , Humans , Mice , Multiple Myeloma/metabolism , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Oxidative Stress , RNA, Untranslated/genetics , Reactive Oxygen Species
15.
Tumour Biol ; 37(11): 14335-14340, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27612480

ABSTRACT

The Ets proteins are a family of transcription factors characterized by an evolutionarily conserved DNA-binding domain and have diverse biological functions including tumor suppressor as well as tumor promoter functions. They are regulated via a complex and diverse number of mechanisms and control key cellular processes. Prostate-derived Ets transcription factor (PDEF), a unique member of the ETS family, is present in tissues with high epithelial content are hormone-regulated, such as prostate, breast, salivary glands, ovaries, colon, airways, and stomach tissues. PDEF (prostate-derived Ets factor) is also referred to as SPDEF (SAM pointed domain containing Ets transcription factor), PSE (mouse homolog), or hPSE (human PSE) in the literature and is the sole member of the PDEF ETS sub-family. The role of PDEF in cancer development is still not fully elucidated though. The present article focuses on the key findings about the PDEF's biological functions, interacting proteins, and its target genes. There is a strong urge to focus on the clinical studies in larger cohort, which elucidate the regulation of PDEF and its target genes, to determine the potential of PDEF as biomarker. Based on the studies discussed in the present article, one can anticipate that PDEF offers a great potential for developing therapeutics against cancer.


Subject(s)
Gene Expression Regulation, Neoplastic/genetics , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , Proto-Oncogene Proteins c-ets/metabolism , Tumor Suppressor Proteins/metabolism , Carcinogenesis/genetics , Cell Line, Tumor , Humans , Male , Prostate/pathology , Protein Structure, Tertiary , Proto-Oncogene Proteins c-ets/genetics , Tumor Suppressor Proteins/genetics
16.
Genetics ; 203(2): 749-62, 2016 06.
Article in English | MEDLINE | ID: mdl-27029730

ABSTRACT

Dis3 encodes a conserved RNase that degrades or processes all RNA species via an N-terminal PilT N terminus (PIN) domain and C-terminal RNB domain that harbor, respectively, endonuclease activity and 3'-5' exonuclease activity. In Schizosaccharomyces pombe, dis3 mutations cause chromosome missegregation and failure in mitosis, suggesting dis3 promotes cell division. In humans, apparently hypomorphic dis3 mutations are found recurrently in multiple myeloma, suggesting dis3 opposes cell division. Except for the observation that RNAi-mediated depletion of dis3 function drives larval arrest and reduces tissue growth in Drosophila, the role of dis3 has not been rigorously explored in higher eukaryotic systems. Using the Drosophila system and newly generated dis3 null alleles, we find that absence of dis3 activity inhibits cell division. We uncover a conserved CDK1 phosphorylation site that when phosphorylated inhibits Dis3's exonuclease, but not endonuclease, activity. Leveraging this information, we show that Dis3's exonuclease function is required for mitotic cell division: in its absence, cells are delayed in mitosis and exhibit aneuploidy and overcondensed chromosomes. In contrast, we find that modest reduction of dis3 function enhances cell proliferation in the presence of elevated Ras activity, apparently by accelerating cells through G2/M even though each insult by itself delays G2/M. Additionally, we find that dis3 and ras genetically interact in worms and that dis3 can enhance cell proliferation under growth stimulatory conditions in murine B cells. Thus, reduction, but not absence, of dis3 activity can enhance cell proliferation in higher organisms.


Subject(s)
Cell Cycle/genetics , Evolution, Molecular , Exosome Multienzyme Ribonuclease Complex/genetics , ras Proteins/genetics , Animals , Caenorhabditis elegans/genetics , Cells, Cultured , Drosophila/genetics , Exosome Multienzyme Ribonuclease Complex/metabolism , Mice , Mice, Inbred C57BL , Schizosaccharomyces/genetics , ras Proteins/metabolism
17.
Exp Hematol ; 44(3): 161-5.e4, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26607597

ABSTRACT

The retinoblastoma gene (RB1) has been implicated as a tumor suppressor in multiple myeloma (MM), yet its role remains unclear because in the majority of cases with 13q14 deletions, un-mutated RB1 remains expressed from the retained allele. To explore the role of Rb1 in MM, we examined the functional consequences of single- and double-copy Rb1 loss in germinal center B cells, the cells of origin of MM. We generated mice without Rb1 function in germinal center B cells by crossing Rb1(Flox/Flox) with C-γ-1-Cre (Cγ1) mice expressing the Cre recombinase in class-switched B cells in a p107(-/-) background to prevent p107 from compensating for Rb1 loss (Cγ1-Rb1(F/F)-p107(-/-)). All mice developed normally, but B cells with two copies of Rb1 deleted (Cγ1-Rb1(F/F)-p107(-/-)) exhibited increased proliferation and cell death compared with Cγ1-Rb1(+/+)-p107(-/-) controls ex vivo. In vivo, Cγ1-Rb1(F/F)-p107(-/-) mice had a lower percentage of splenic B220+ cells and reduced numbers of bone marrow antigen-specific secreting cells compared with control mice. Our data indicate that Rb1 loss induces both cell proliferation and death in germinal center B cells. Because no B-cell malignancies developed after 1 year of observation, our data also suggest that Rb1 loss is not sufficient to transform post-germinal center B cells and that additional, specific mutations are likely required to cooperate with Rb1 loss to induce malignant transformation.


Subject(s)
B-Lymphocytes/metabolism , Cell Proliferation , Cell Transformation, Neoplastic/metabolism , Germinal Center/metabolism , Mutation , Retinoblastoma Protein/deficiency , Animals , B-Lymphocytes/pathology , Cell Death , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/pathology , Germinal Center/pathology , Mice , Mice, Knockout
18.
Int J Cardiovasc Imaging ; 31(8): 1503-9, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26245470

ABSTRACT

Hypertrophic cardiomyopathy (HCM) affects the right ventricle (RV) because of the anatomically hypertrophied septum and plausibly by extension of the myopathic process to the RV. We sought to investigate RV strain in patients with left ventricular hypertrophy secondary to either HCM or hypertension (H-LVH). Our cross-sectional study included 32 patients with HCM, 21 patients with H-LVH, and 11 healthy subjects, who were evaluated with transthoracic echocardiography. Using a dedicated software package, bi-dimensional acquisitions were analyzed to measure segmental longitudinal strain in apical views. Right ventricular global longitudinal strain (GLS) was calculated by averaging septal and right free wall strains. The HCM and H-LVH groups were comparable for age and demographic characteristics. Right ventricular tricuspid annular plane systolic excursion was not significantly different between HCM and H-LVH subjects. Moreover, RV GLS, septal and lateral RV myocardial strain were significantly impaired in patients with HCM (all p < 0.001). Regional and global RV strain parameters were not significantly impaired in H-LVH compared to healthy controls An RV GLS cut-off value of >14.9% differentiated HCM and H-LVH with a 90% sensitivity and a 95% specificity (p < 0.001). RV strain parameters are impaired in patients with HCM. Assessment of two-dimensional RV strain parameters could help differentiate between HCM and H-LVH.


Subject(s)
Cardiomyopathy, Hypertrophic/diagnostic imaging , Echocardiography, Doppler, Color , Hypertension/diagnostic imaging , Hypertrophy, Left Ventricular/diagnostic imaging , Myocardial Contraction , Ventricular Dysfunction, Right/diagnostic imaging , Ventricular Function, Right , Adult , Aged , Cardiomyopathy, Hypertrophic/complications , Cardiomyopathy, Hypertrophic/physiopathology , Cross-Sectional Studies , Diagnosis, Differential , Female , Humans , Hypertension/complications , Hypertension/physiopathology , Hypertrophy, Left Ventricular/etiology , Hypertrophy, Left Ventricular/physiopathology , Image Interpretation, Computer-Assisted , Male , Middle Aged , Observer Variation , Predictive Value of Tests , Reproducibility of Results , Retrospective Studies , Risk Factors , Software , Ventricular Dysfunction, Right/etiology , Ventricular Dysfunction, Right/physiopathology
19.
Biomed Res Int ; 2014: 827105, 2014.
Article in English | MEDLINE | ID: mdl-25276821

ABSTRACT

Takayasu's arteritis (TA) was reported as an eye disease in the year 1905 and later was confirmed as a vasculitis. Since then, the etiology of the disease remains unknown; however, characteristic clinical features suggest multiple causative factors. Recent progress in vascular biology and other disciplines enlightens the pathophysiology of TA and demonstrated induction of various nonspecific inflammatory symptoms and destruction of the arterial wall, which leads to aneurysms and rupture of the affected arteries. Matrix metalloproteinases (MMPs) as an enzyme family have well-established roles in several vascular pathologies including intima formation, atherosclerosiss and aneurysms. MMPs have been proposed to be one of the molecules with a potential of having dual role in the course of TA, first as an active participant in pathophysiology and secondly as a diagnostic biomarker for TA disease. The desire to improve our understanding of the importance of MMPs and their endogenous inhibitors (TIMPs) in TA disease and for the development of therapeutic agents has inspired basic and clinical scientists for over a decade. In the present paper, we summarized the scientific rationale which highlights the signatures of matrix metalloproteinases and their endogenous inhibitors in pathophysiology as well as their being a potential candidate as biomarker for Takayasu's arteritis.


Subject(s)
Matrix Metalloproteinases/metabolism , Takayasu Arteritis/enzymology , Animals , Biomarkers/metabolism , Humans , Matrix Metalloproteinases/chemistry , Takayasu Arteritis/physiopathology , Tissue Inhibitor of Metalloproteinases/metabolism
20.
Am J Cardiol ; 114(2): 290-3, 2014 Jul 15.
Article in English | MEDLINE | ID: mdl-24874163

ABSTRACT

The current definition of peripartum cardiomyopathy (PC) is restricted to patients with left ventricular systolic dysfunction (ejection fraction [EF]<45%). Data on peripartum heart failure (HF) with normal EF are sparse. We describe clinical characteristics of patients with normal (≥55%) and patients with low (<45%) left ventricular ejection fractions (LVEFs). Electronic medical records (2006 to 2013) of our tertiary care center were retrospectively screened to identify peripartum HF with normal EF, defined as an entity meeting Framingham criteria for HF with symptom onset during the last month of pregnancy or up to 5 months after delivery and with an EF of ≥55%. Clinical characteristics, echocardiographic parameters, and outcomes of these patients were compared with age-matched control patients with traditionally defined PC (EF<45%). A total of 25 patients with PC and EF≥55% were identified. Exclusion of hypertension (n=9), preeclampsia (n=1), and diabetes mellitus (n=2) yielded 13 patients with PC and EF≥55%. Age-matched patients with traditional PC (EF<45%) constituted controls (n=16). Compared with patients with PC and low LVEF, patients with PC and normal LVEF had lower B-type natriuretic peptide levels, systolic and diastolic left ventricular dimensions, left atrial size, and incidence of decompensated HF during delivery (p<0.05). Compared with historical age-matched controls, patients with normal LVEF exhibited attenuated E' mitral annular velocities. On follow-up, these patients were associated with a lower New York Heart Association functional class. In conclusion, peripartum HF with normal LVEF appears to be a distinct entity.


Subject(s)
Heart Failure, Systolic/physiopathology , Peripartum Period , Pregnancy Complications, Cardiovascular , Stroke Volume , Ventricular Function, Left/physiology , Adult , Echocardiography , Female , Follow-Up Studies , Heart Failure, Systolic/diagnostic imaging , Heart Failure, Systolic/epidemiology , Humans , Incidence , Pregnancy , Retrospective Studies , United States/epidemiology , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...