ABSTRACT: Gene array experiment to identify genes that are upregulated by saturating creatine levels in vitro and potentially inhibiting creatine transporter (CrT) activity
Project description:We sought to investigate the mechanisms of CrT modulation by saturating extracellular Cr. For this purpose, we used an in vitro system of 3T3 fibroblasts stably overexpressing CrT and followed a global gene array approach to test the hypothesis that saturating intracellular [Cr] increases the expression of candidate molecules that inhibit CrT activity. In this way, we would elucidate mechanisms of redox regulation in cases of fluctuating energy demands. 3T3-CrT cells were grown on 6-well plates to 70% confluency. n=3 replicate wells were treated with 5mM creatine monohydrate in growth media and n=3 wells remained untreated (controls).
Project description:We sought to investigate the mechanisms of CrT modulation by saturating extracellular Cr. For this purpose, we used an in vitro system of 3T3 fibroblasts stably overexpressing CrT and followed a global gene array approach to test the hypothesis that saturating intracellular [Cr] increases the expression of candidate molecules that inhibit CrT activity. In this way, we would elucidate mechanisms of redox regulation in cases of fluctuating energy demands.
Project description:The identification of surrogate single nucleotide polymorphism (SNP) markers that can predict responses to preoperative chemoradiotherapy (CRT) in rectal cancer patients. Genome-wide association studies in clinical populations are theoretically capable of identifying markers that are capable of tumor regression after CRT. We used Affymetrix’s SNP Array 6.0 to detail genetic polymorphism of patient’s group showing differential responsiveness to preoperative CRT and profiled SNP biomarkers.
Project description:Neoadjuvant chemoradiotherapy (CRT) is used in locally advanced rectal cancer when tumours threaten the circumferential resection margin. A variable response to treatment remains, notwithstanding potentially significant morbidity, and no clinically routinely used predictive biomarkers guide decision making. This experimental study aimed to identify significantly differentially expressed proteins between patients responding or not to CRT, using novel temporal proteomic profiling, and to validate any proteins of interest.
Project description:Next-generation proteomics of human brain organoids derived from individuals with creatine transporter deficiency in order to assess their characteristics as models of the pathophysiology.
Project description:α-1-antitrypsin (AAT) regulates protease activity in the lungs and liver. The presence of one or more copies of a mutant Z allele (AAT (E342K), called ATZ), results in low serum levels of ATZ along with intracellular inclusions of polymeric forms, causing lung emphysema and liver cirrhosis. Our experiments show that calreticulin (CRT), an endoplasmic reticulum (ER) glycoprotein chaperone, promotes the secretory trafficking of ATZ, enhancing the media to cell ratio. This effect is more specific for ATZ compared with AAT, and is only partially dependent on the glycan-binding site of CRT. The CRT-related chaperone calnexin (CNX) does not promote enhanced ATZ secretory trafficking, despite the higher cellular abundance of CNX-ATZ complexes. CRT deficiency alters the distributions of ATZ-ER chaperone complexes, increasing ATZ-BiP binding and inclusion body (IB) formation, and reducing ATZ interactions with components required for ER-Golgi trafficking. These findings indicate a novel role for CRT in promoting the secretory trafficking of a polymerogenic protein. Inefficient secretory trafficking of ATZ in the absence of CRT is coincident with enhanced accumulation of ER-derived ATZ IBs.
Project description:Purpose: Adding losartan (LOS) to FOLFIRINOX (FFX) chemotherapy followed by chemoradiation (CRT) resulted in 61% R0 surgical resection in our phase II trial in patients with locally advanced pancreatic cancer (LAPC). Here we identify potential mechanisms of benefit by assessing the effects of neoadjuvant losartan on the stromal tumor microenvironment. Experimental Design: We performed a gene expression and immunofluorescence (IF) analysis using archived surgical samples from patients treated with LOS+FFX+CRT (NCT01821729), FFX+CRT (NCT01591733) or surgery upfront, without any neoadjuvant therapy. We also conducted a longitudinal analysis of multiple biomarkers in the plasma of treated patients. Results: In comparison to FFX+CRT, LOS+FFX+CRT downregulated immunosuppression and pro-invasion genes. Overall survival (OS) was associated with DC and antigen presentation genes for patients treated with FFX+CRT, and with immunosuppression and invasion genes or DC– and blood vessel-related genes for those treated with LOS+FFX+CRT. Furthermore, losartan induced specific changes in circulating levels of IL-8, sTie2 and TGF-. IF revealed significantly less residual disease in lesions treated with LOS+FFX+CRT. Lastly, patients with a complete/near complete pathological response in the LOS+FFX+CRT-treated group had reduced CD4+FOXP3+ regulatory T cells (Tregs), fewer immunosuppressive FOXP3+ cancer cells (C-FOXP3) and increased CD8+ T cells in PDAC lesions. Conclusions: Adding losartan to FFX+CRT reduced pro-invasion and immunosuppression related genes which were associated with improved survival in patients with LAPC. Lesions from responders in the LOS+FFX+CRT-treated group had reduced Tregs, decreased C-FOXP3 and increased CD8+ T cells. These findings suggest that losartan may potentiate the benefit of FFX+CRT by reducing immunosuppression.
Project description:Biallelic mutations in the DCPS gene that disrupt the decapping activity of the DcpS scavenger decapping enzyme lead to neurodevelopmental deficiencies and intellectual disability. However, how the neurogenesis defects arise in these individuals remains unknown. Here we show that cells derived from DCPS mutant individuals have a metabolic deficiency in their creatine biosynthetic pathway. The cells possess reduced levels of creatine and a corresponding elevation of the creatine precursor, guanidinoacetate (GAA), due to reduced levels of guanidinoacetate methyltransferase mRNA and protein. Importantly, the compromised neurogenesis as well as neurite outgrowth observed in DcpS mutant induced pluripotent stem cell differentiation into neurons was reversed upon supplementation of creatine monohydrate into the culture medium. These findings suggest creatine deficiency as the underlying etiology of the neurogenetic defect in DcpS mutant cells and a potential driver of the neurological deficienciesin affected individuals.
