148 research outputs found
sj-docx-1-gae-10.1177_25168657231184665 – Supplemental material for SARS-CoV-2 Covid-19 Infection During Pregnancy and Differential DNA Methylation in Human Cord Blood Cells From Term Neonates
No full textSupplemental material, sj-docx-1-gae-10.1177_25168657231184665 for SARS-CoV-2 Covid-19 Infection During Pregnancy and Differential DNA Methylation in Human Cord Blood Cells From Term Neonates by Pedro Urday, Suhita Gayen nee’ Betal, Rochelle Sequeira Gomes, Huda B Al-Kouatly, Kolawole Solarin, Joanna SY Chan, Dongmei Li, Irfan Rahman, Sankar Addya, Rupsa C Boelig and Zubair H Aghai in Epigenetics Insights</p
Ethanol potentiates HIV-1 gp120-induced apoptosis in human neurons via both the death receptor and NMDA receptor pathways
No full textNeuronal loss is a hallmark of AIDS dementia syndromes. Human immunodeficiency virus type I (HIV-1)-specific proteins may induce neuronal apoptosis, but the signal transduction of HIV-1 gp120-induced, direct neuronal apoptosis remains unclear. Ethanol (EtOH) is considered to be an environmental co-factor in AIDS development. However, whether EtOH abuse in patients with AIDS increases neuronal dysfunction is still uncertain. Using pure, differentiated, and post-mitotic NT2.N-derived human neurons, we investigated the mechanisms of HIV-1 and/or EtOH-related direct neuronal injury and the molecular interactions between HIV-1-specific proteins and EtOH. It was demonstrated that NT2.N neurons were susceptible to HIV-1 Bal (R5-tropic strain) gp120-induced direct cell death. Of importance, EtOH induced cell death in human neurons in a clinically-relevant dose range and EtOH strongly potentiated HIV-1 gp120-induced neuronal injury at low and moderate concentrations. Furthermore, this potentiation of neurotoxicity could be blocked by N-methyl-d-aspartate (NMDA) receptor subunit 2B (NR2B) antagonists. We analyzed human genomic profiles in these human neurons, using Affymetrix genomics technology, to elucidate the apoptotic pathways involved in HIV-1- and EtOH-related neurodegeneration. Our findings indicated significant over-expression of selected apoptosis functional genes. Significant up-regulation of TRAF5 gene expression may play an essential role in triggering potentiation by EtOH of HIV-1 gp120-induced neuronal apoptosis at early stages of interaction. These studies suggested that two primary apoptotic pathways, death receptor (extrinsic) and NMDA receptor (intrinsic)-related programmed cell-death pathways, are both involved in the potentiation by EtOH of HIV-1 gp120-induced direct human neuronal death. Thus, these data suggest rationally-designed, molecular targets for potential anti-HIV-1 neuroprotection
Regulation of miR106b cluster through the RB pathway: mechanism and functional targets.
No full textThe RB pathway plays a critical role in proliferation control that is commonly subverted in tumor development. However, restoration of RB pathway function can be elicited in many tumor cells by the inhibition of CDK4/6 activity that leads to dephosphorylation of RB and subsequent repression of E2F-mediated transcription. In this context, active RB/E2F complexes inhibit the expression of a critical program of coding genes that promote cell cycle progression. However, the non-coding RNA target genes downstream from RB that could be relevant for tumor biology remain obscure. Here, miRNA gene expression profiling identified the miR106b cluster as being efficiently repressed with CDK4/6 inhibition in an E2F and RB-dependent manner. Importantly, the miR106B-cluster is intragenic of MCM7, and through a series of functional studies, the basis of MCM7 regulation and concordant expression of the miRNA species within the 106b cluster was determined. Importantly, RB-mediated repression of the 106b cluster enhances the transcript levels of p21Cip1 and PTEN. These data provide a mechanistic basis for cross-talk between the RB pathway and p21 and PTEN through the regulation of the MCM7/miR106b locus. © 2013 Landes Bioscience
Mechanisms of Endothelial Cell Attachment, Proliferation, and Differentiation on 4 Types of Platinum-Based Endovascular Coils
No full textObjective: A subarachnoid hemorrhage is neurologically devastating, with 50% of patients becoming disabled or deceased. Advent of Guglielmi detachable coils in 1995 permitted endovascular treatment of cerebral aneurysms. Coiling is efficacious and safe, but durability needs improvement, as nearly 20% of patients require further invasive intervention secondary to aneurysm recurrence. The aim of this study is to develop an in vitro model of endothelial cell (EC) proliferation and differentiation on four types of platinum-based coils, using gene expression profiling to understand EC biology as they colonize and differentiate on coils. Methods: Human umbilical vein ECs were grown in vitro on platinum coil segments. Growth patterns were assessed as a function of coil type. Gene expression profiles for coil attached versus coil unattached ECs were determined using immunohistochemistry and gene array analysis. Results: ECs showed rapid, robust attachment to all coil types. Some detachment occurred within 24-48 hours. Significant growth of remaining attached cells occurred during the next week, creating a confluence on coils and within coil grooves. Similar growth curve results were obtained with human brain ECs on platinum-based coil surfaces. Differentiation markers in attached cells (α1, α2, β1 integrins) were expressed on immunostaining, whereas microarray gene expression revealed 48 up-regulated and 68 down-regulated genes after 24-hour growth on coils. Major pathways affected as a function of time of colonization on coils and coil type included those involved in regulation of cell cycle and cell signaling. Conclusions: We developed an in vitro model for evaluating endothelialization of platinum coils to optimize coil design to support robust EC colonization and differentiation. © 2014 Elsevier Inc. All rights reserved
Four-laser scanning confocal system for microarray analysis.
No full textWe have constructed a confocal scanner suitable for routine microarray analysis from commercially available parts. We have outlined the details that should be considered when designing such an instrument and listed some of the specific components comprising the system [the full list of system components is available on CD from the corresponding author (D.J.G.) at no charge]. Here, we describe the methods used to test the linearity and sensitivity of the instrument. Performance was evaluated with two commonly used dyes, fluorescein and Cy5. While the instrument had a linear correlation between the dye concentration and fluorescence intensity, the observed deviation from a slope of 1.0 underscores the importance of running multipoint calibration experiments to obtain accurate dye quantitation over the full dynamic range of the scanner. This method has utility in testing commercial instruments in addition to the scanner described here. An array with over 300 spots dyed with Cy3 was scanned with our instrument and a high-end commercial instrument. The agreement between the two instruments was very good over a 1000-fold intensity range. Our scanner is a cost-effective alternative to more costly commercial scanners with similar capabilities
A de novo supernumerary genomic discontinuous ring chromosome 21 in a child with mild intellectual disability
No full textSmall supernumerary marker chromosomes (sSMCs) are structurally abnormal extra chromosomes that cannot be unambiguously identified or characterized by conventional banding techniques alone, and they are generally equal in size or smaller than chromosome 20 of the same metaphase spread. Small supernumerary ring chromosomes (sSRCs), a smaller class of marker chromosomes, comprise about 10% of the cases. For various reasons these marker chromosomes have been the most difficult to characterize; although specific syndromes have not yet been defined, 60% of cases are associated with an abnormal phenotype. The chromosomal material involved, the degree and tissutal distribution of mosaicism, and the possible presence of uniparental disomy, are the important factors determining whether or not the ring chromosome will give rise to symptoms. Using conventional and molecular cytogenetics approaches we identified a de novo chromosome 21 sSRC in a child with speech delay and mild intellectual disability. By using aCGH analysis and SNP arrays, we report the presence of two discontinuous regions of chromosome 21 and the paternal origin of the sSRC. A thorough neuropsychiatric evaluation is also provided. Only few other cases of complex discontinuous ring chromosomes have been described in detail. © 2011 Wiley-Liss, Inc
Roles of β-catenin signaling in phenotypic expression and proliferation of articular cartilage superficial zone cells.
No full textThe superficial zone (SFZ) of articular cartilage has unique structural and biomechanical features, is thought to promote self-renewal of articular cartilage, and is thus important for joint long-term function, but the mechanisms regulating its properties remain unclear. Previous studies revealed that Wnt/β-catenin signaling is continuously active in SFZ, indicating that it may be essential for SFZ function. Thus, we examined whether Wnt/β-catenin signaling regulates proliferation and phenotypic expression in SFZ cells. Using transgenic mice, we found that acute activation of Wnt/β-catenin signaling increases SFZ thickness, Proteoglycan 4 (Prg4, also called lubricin) expression and the number of slow-cell cycle cells, whereas conditional ablation of β-catenin causes the opposite. We developed a novel method to isolate SFZ cell-rich populations from the epiphyseal articular cartilage of neonatal mice, and found that the SFZ cells in culture exhibit a fibroblastic cytoarchitecture and higher Prg4 and Ets-related gene (Erg) expression and lower aggrecan expression compared with chondrocyte cultures. Gene array analyses indicated that SFZ cells have distinct gene expression profiles compared with underlying articular chondrocytes. Treatment of Wnt3a strongly stimulated SFZ cell proliferation and maintained strong expression of Prg4 and Erg, whereas ablation of β-catenin strongly impaired proliferation and phenotypic expression. When the cells were transplanted into athymic mice, they formed Prg4- and aggrecan-expressing cartilaginous masses attesting to their autonomous phenotypic capacity. Ablation of β-catenin caused a rapid loss of Prg4 gene expression and strong increases in expression of aggrecan and collagen 10, the latter being a trait of hypertrophic chondrocytes. Together, the data reveal that Wnt/β-catenin signaling is a key regulator of SFZ cell phenotype and proliferation, and may be as important for articular cartilage long-term function
Transcription factor Stat3 stimulates metastatic behavior of human prostate cancer cells in vivo, whereas Stat5b has a preferential role in the promotion of prostate cancer cell viability and tumor growth.
No full textIdentification of the molecular changes that promote viability and metastatic behavior of prostate cancer is critical for the development of improved therapeutic interventions. Stat5a/b and Stat3 are both constitutively active in locally-confined and advanced prostate cancer, and both transcription factors have been reported to be critical for the viability of prostate cancer cells. We recently showed that Stat3 promotes metastatic behavior of human prostate cancer cells not only in vitro but also in an in vivo experimental metastases model. In this work, we compare side-by-side Stat5a/b versus Stat3 in the promotion of prostate cancer cell viability, tumor growth, and induction of metastatic colonization in vivo. Inhibition of Stat5a/b induced massive death of prostate cancer cells in culture and reduced both subcutaneous and orthotopic prostate tumor growth, whereas Stat3 had a predominant role over Stat5a/b in promoting metastases formation of prostate cancer cells in vivo in nude mice. The molecular mechanisms underlying the differential biological effects induced by these two transcription factors involve largely different sets of genes regulated by Stat5a/b versus Stat3 in human prostate cancer model systems. Of the two Stat5 homologs, Stat5b was more important for supporting growth of prostate cancer cells than Stat5a. This work provides the first mechanistic comparison of the biological effects induced by transcription factors Stat5a/b versus Stat3 in prostate cancer
Caveolin-1 overexpression enhances androgen-dependent growth and proliferation in the mouse prostate
No full textProstate cancer (PCa) continues to be one of the leading causes of cancer-related deaths among American men. The prostate relies upon the androgen receptor (AR) to mediate the effects of androgens on normal growth, a reliance that is maintained during malignant prostate growth. Caveolin-1 (Cav-1), the main structural component of caveolae, has been shown to promote the malignant growth and invasion of prostate tumors. In vitro work has shown that Cav-1 can act as an AR coactivator by enhancing its transciptional activity. However, it is unknown how Cav-1 affects androgen-dependent growth and signaling in vivo. To explore this role, a novel mouse model of Cav-1 overexpression was developed with a hormone-insensitive promoter. Cav-1 transgenic (Tg) mice subjected to castration and androgen stimulation display enlarged prostate weights and increased DNA synthesis. Through gene transcript and proteomic profiling, we demonstrate that Cav-1 overexpression favors androgen-regulated responses and enhances processes involved in transcription, cell cycle progression and protein synthesis. Interestingly, Cav-1 overexpression was associated with an increase in the phosphorylation of AR on serine 210, a post-translational modification linked to its activity under androgen-stimulated conditions. In addition, these mice exhibited an increase in the phosphorylation of ribosomal S6 protein on serine 235/236 (pS6), a marker of protein synthesis and a downstream component of the mTOR pathway. Thus, Cav-1 Tg mice could serve as a novel model for studying AR-regulated pathways involved in prostate growth and proliferation. © 2011 Elsevier Ltd. All rights reserved
ChIP sequencing of cyclin D1 reveals a transcriptional role in chromosomal instability in mice.
No full textChromosomal instability (CIN) in tumors is characterized by chromosomal abnormalities and an altered gene expression signature; however, the mechanism of CIN is poorly understood. CCND1 (which encodes cyclin D1) is overexpressed in human malignancies and has been shown to play a direct role in transcriptional regulation. Here, we used genome-wide ChIP sequencing and found that the DNA-bound form of cyclin D1 occupied the regulatory region of genes governing chromosomal integrity and mitochondrial biogenesis. Adding cyclin D1 back to Ccnd1-/- mouse embryonic fibroblasts resulted in CIN gene regulatory region occupancy by the DNA-bound form of cyclin D1 and induction of CIN gene expression. Furthermore, increased chromosomal aberrations, aneuploidy, and centrosome abnormalities were observed in the cyclin D1-rescued cells by spectral karyotyping and immunofluorescence. To assess cyclin D1 effects in vivo, we generated transgenic mice with acute and continuous mammary gland-targeted cyclin D1 expression. These transgenic mice presented with increased tumor prevalence and signature CIN gene profiles. Additionally, interrogation of gene expression from 2,254 human breast tumors revealed that cyclin D1 expression correlated with CIN in luminal B breast cancer. These data suggest that cyclin D1 contributes to CIN and tumorigenesis by directly regulating a transcriptional program that governs chromosomal stability
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