INTRODUCTION. Fixation with formalin, a widely adopted procedure to preserve tissue samples, leads to extensive degradation of nucleic acids and thereby compromises procedures like microarray-based gene expression profiling. We hypothesized that RNA fragmentation is caused by activation of RNAses during the interval between formalin penetration and tissue fixation. To prevent RNAse activation, a series of tissue samples were kept under-vacuum at 4C until fixation and then fixed at 4C, for 24 hours, in formalin followed by 4 hours in ethanol 95%.
Formalin fixation at low temperature better preserves nucleic acid integrity.
Specimen part
View SamplesProgressive tissue fibrosis is a major cause of morbidity, and idiopathic pulmonary fibrosis (IPF) is a terminal illness characterized by unremitting matrix deposition in the lung with very limited choice of therapies. The imcomplete understanding of the mechanisms of progressive fibrosis curbs the progress in therapeutics development. Of which, the origin of fibrotic fibroblasts has been poorly defined during the pathogenesis of tissue fibrosis. Here, we fate-mapped a early embryonic transcription factor T-box gene 4 (Tbx4)-derived mesenchymal progenitors in injured adult lung and found that Tbx4+ lineage cells are the major source of myofibroblasts. The ablation of Tbx4+ cells or disruption of Tbx4 signaling attenuated lung fibrosis in bleomycin injury model in mice in vivo. Furthermore, Tbx4+ fibroblasts are more invasive and the regulation of fibroblast invasiveness by Tbx4 is through mediating hyaluronan synthase 2 (HAS2). This study identified a major mesenchymal transcription factor driving the development of fibrotic fibroblasts during lung fibrosis. Understanding the origin, signaling, and functions of these fibroblasts would prove pivotal in the development of therapeutics for patients with progressive fibrotic diseases.
Transcription factor TBX4 regulates myofibroblast accumulation and lung fibrosis.
Specimen part
View SamplesTuberous Sclerosis Complex (TSC) is a disease caused by autosomal dominant mutations in the TSC1 or TSC2 genes, and is characterized by tumor susceptibility, brain lesions, seizures and behavioral impairments. The TSC1 and TSC2 genes encode proteins forming a complex (TSC), which is a major regulator and suppressor of mammalian target of rapamycin (mTOR) in complex 1 (mTORC1), a signaling complex that promotes cell growth and proliferation. TSC1/2 loss of heterozygosity (LOH) and the subsequent complete loss of TSC regulatory activity in null cells causes mTORC1 dysregulation and TSC-associated brain lesions or other tissue tumors. However, it is not clear whether TSC1/2 heterozygous brain cells are abnormal and contribute to TSC neuropathology. To investigate this issue, we generated induced pluripotent stem cells (iPSCs) from TSC patients and unaffected controls, and utilized these to obtain neural progenitor cells (NPCs) and differentiated neurons in vitro. These patient-derived TSC2 heterozygous NPCs were delayed in their ability to differentiate into neurons. Patient-derived progenitor cells also exhibited a modest activation of mTORC1 signaling downstream of TSC, and a marked attenuation of upstream PI3K/AKT signaling. We further show that pharmacologic AKT inhibition, but not mTORC1 inhibition, causes a neuronal differentiation delay, mimicking the patient phenotype. Together these data suggest that heterozygous TSC2 mutations disrupt neuronal development, potentially contributing to the disease neuropathology, and that this defect may result from dysregulated AKT signaling in neural progenitor cells. Overall design: Two replicates each of TSC#1 and CON#1 NPC cell RNA were prepared for sequencing library preparation and seqeuencing.
Neural progenitors derived from Tuberous Sclerosis Complex patients exhibit attenuated PI3K/AKT signaling and delayed neuronal differentiation.
Specimen part, Subject
View SamplesChronic obstructive pulmonary disease (COPD), the fourth leading cause of death globally, is influenced by both cigarette smoking and genetic determinants. We have previously identified iron-responsive element binding protein 2 (IRP2) as a candidate COPD susceptibility gene based on genetic association studies, with IRP2 increased in the lungs of COPD patients. Here we demonstrate that mice deficient in IRP2 are protected from cigarette smoke (CS)-induced COPD. Using RIP-Seq, RNA-Seq, gene expression and pathway analysis, we identify IRP2 as a regulator of mitochondrial function in the lung. We show that an increase in IRP2 results in a cytochrome c oxidase (COX)-dependent alteration in oxidative capacity and mitochondrial-iron dysfunction involving frataxin. We demonstrate that mice with impaired COX or frataxin activity have altered responses to CS and show that overexpressing IRP2 in vivo alters mitochondrial dynamics. These data suggest a critical role of the mitochondria-iron axis in mediating the pathogenesis of COPD.
Mitochondrial iron chelation ameliorates cigarette smoke-induced bronchitis and emphysema in mice.
Sex, Specimen part
View SamplesMicroarray based mRNA profiling was used to identify the mechanism of action for the small molecule b-AP15.
Inhibition of proteasome deubiquitinating activity as a new cancer therapy.
Cell line, Treatment
View SamplesJunction Adhesion Molecule-A (JAM-A) is present on leukocytes and platelets where it promotes cell adhesion and motility. We are interested in an interaction between JAM-A and tumor progression/metastases. To address this point, we mated JAM-A-/- mice and mouse mammary tumor model MMTV-PyMT mice which, which express polyoma middle T antigen under the control of mouse mammary tumor virus. MMTV-PyMT mice show 100% penetration of mammary tumor and highly metastases to lung. MMTV-PyMT mice without JAM-A show less primary tumor progression, therefore JAM-A enhance primary tumor progression. Then we are addressing the molecular mechanism of this phenomenon by in vivo. Furthermore, we would like to examine JAM-A deficient MMTV tumor signature.
Abrogation of junctional adhesion molecule-A expression induces cell apoptosis and reduces breast cancer progression.
Specimen part
View SamplesMicroarray based mRNA profiling was used to identify the mechanism of action for the small molecule VLX600.
Iron chelators target both proliferating and quiescent cancer cells.
Disease, Cell line, Treatment
View SamplesMicroarray based mRNA profiling was used to charactarize and compare the gene expression in cells grown as monolayer or spheroids.
Induction of mitochondrial dysfunction as a strategy for targeting tumour cells in metabolically compromised microenvironments.
Cell line
View SamplesMicroarray based mRNA profiling was used to charactarize the response to the compound VLX600 in cells grown as spheroids. Cells used was colon cancer cells HCT116 and HCT116HIF1a knock-out.
Induction of mitochondrial dysfunction as a strategy for targeting tumour cells in metabolically compromised microenvironments.
Cell line, Treatment
View SamplesFollowing androgen ablation therapy (AAT), the vast majority of prostate cancer patients develop treatment resistance with a median time of 18-24 months to disease progression. To identify molecular targets that aid in prostate cancer cell survival and contribute to the androgen independent phenotype, we evaluated changes in LNCaP cell gene expression during 12 months of androgen deprivation. At time points reflecting critical growth and phenotypic changes, we performed Affymetrix expression array analysis to examine the effects of androgen deprivation during the acute response, during the period of apparent quiescence, and during the emergence of highly proliferative, androgen-independent prostate cancer cells (LNCaP-AI). We discovered alterations in gene expression for a host of molecules associated with promoting prostate cancer cell growth and survival, regulating cell cycle progression, apoptosis and adrenal androgen metabolism, in addition to AR co-regulators and markers of neuroendocrine disease. These findings illustrate the complexity and unpredictable nature of cancer cell biology and contribute greatly to our understanding of how prostate cancer cells likely survive AAT. The value of this longitudinal approach lies in the ability to examine gene expression changes throughout the cellular response to androgen deprivation; it provides a more dynamic illustration of those genes which contribute to disease progression in addition to specific genes which constitute a malignant androgen-independent phenotype. In conclusion, it is of great importance that we employ new approaches, such as the one proposed here, to continue exploring the cellular mechanisms of therapy resistance and identify promising targets to improve cancer therapeutics.
Longitudinal analysis of androgen deprivation of prostate cancer cells identifies pathways to androgen independence.
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