Project description:Apolipoprotein E4 (APOE4) is the strongest genetic risk factor for late-onset Alzheimer’s disease (LOAD), leading to earlier age of clinical onset and exacerbating pathologies. There is a critical need to identify protective targets. Recently, a rare APOE variant, APOE3-R136S (Christchurch), was found to protect against early-onset AD in a PSEN1-E280A carrier. We sought to determine if the R136S mutation also protects against APOE4-driven effects in LOAD. We generated tauopathy mouse and human iPSC-derived neuron models carrying human APOE4 with the homozygous or heterozygous R136S mutation. We found that the homozygous R136S mutation rescued APOE4-driven Tau pathology, neurodegeneration, and neuroinflammation. The heterozygous R136S mutation partially protected against APOE4-driven neurodegeneration and neuroinflammation, but not Tau pathology. Single-nucleus RNA-sequencing revealed that the APOE4-R136S mutation increased disease-protective and diminished disease-associated cell populations in a gene dose-dependent manner. Thus, the APOE-R136S mutation protects against APOE4-driven AD pathologies, providing a target for therapeutic development against AD.
Project description:Non-inflamed (cold) tumors such as leiomyosarcoma (LMS) do not benefit from immune checkpoint blockade (ICB) monotherapy. Combining ICB with angiogenesis-, or poly-ADP ribose polymerase (PARP) inhibitors may increase tumor immunogenicity by altering the immune cell composition of the tumor microenvironment (TME). The DAPPER phase II study evaluated the safety, immunologic, and clinical activity of ICB-based combinations in pre-treated LMS patients.
Project description:Neuroinflammation plays a role in the progression of several neurodegenerative disorders. We used a lipolysaccharide (LPS) model of neuroinflammation to characterize the gene expression changes underlying the inflammatory and behavioral effects of neuroinflammation. A single intracerebroventricular injection of LPS (5 ug) was administered into the lateral ventricle of mice and, 24 hours later, we examined gene expression in the cerebral cortex and hippocampus using microarray technology. Gene Ontology (GO) terms for inflammation and the ribosome were significantly enriched by LPS, whereas GO terms associated with learning and memory had decreased expression. We detected 224 changed transcripts in the cerebral cortex and 170 in the hippocampus. Expression of Egr1 (also known as Zif268) and Arc, two genes associated with learning and memory, was significantly lower in the cortex, but not hippocampus, of LPS-treated animals. Overall, altered expression of these genes may underlie some of the inflammatory and behavioral effects of neuroinflammation. Mice were given intracerebroventricular injections of saline vehicle (n = 4) or lipopolysaccharide (n = 4). Twenty-four hours later, we dissected the hippocampus and cerebral cortex and processed the tissue for microarray analysis. Gene expression changes observed in the microaray data were validated with quantitative real-time PCR.
Project description:Interorgan crosstalk via secreted hormones and metabolites is a fundamental aspect of mammalian metabolic physiology. Beyond the highly specialized endocrine cells, peripheral tissues are emerging as an important source of metabolic hormones that influence energy and nutrient metabolism and contribute to disease pathogenesis. Neuregulin 4 (Nrg4) is a fat-derived hormone that protects mice from nonalcoholic steatohepatitis (NASH) and NASH-associated liver cancer by shaping hepatic lipid metabolism and the liver immune microenvironment. Despite its enriched expression in brown fat, whether NRG4 plays a role in thermogenic response and mediates the metabolic benefits of cold exposure remain unexplored. Here we show that Nrg4 expression in inguinal white adipose tissue (iWAT) is highly responsive to chronic cold exposure. Nrg4 deficiency impairs beige fat induction and renders mice more susceptible to diet-induced metabolic disorders under mild cold conditions. Using mice with adipocyte and hepatocyte-specific Nrg4 deletion, we reveal that adipose tissue-derived NRG4, but not hepatic NRG4, is essential for beige fat induction following cold acclimation. Furthermore, treatment with recombinant NRG4-Fc fusion protein promotes beige fat induction in iWAT and improves metabolic health in diet-induced obese mice. These findings highlight a critical role of NRG4 in mediating beige fat induction and preserving metabolic health under mild cold conditions.
Project description:Research in recent years has focused on environmental effects that control tissue functionality and systemic metabolism. We show here in a retrospective analysis that presence of brown adipocytes and date of birth are correlated and linked to BMI. In a mouse model system, we demonstrate that pre-conception cold exposure leads to improved systemic metabolism and protects from diet induced obesity, through the sperm via the paternal lineage. Using a brown fat ablation model, we show that this effect is mediated by brown adipose tissue. Furthermore, through RNAseq and DNA methylation analysis we identify Adrb3 as a putative signaling mechanism which could mediate the effects of pre-conception cold exposure and could account for the heterogeneity of brown adipose tissue responsiveness. Taken together, our results identify paternal cold exposure as a stimulus which induces a hyper-active state in brown adipose tissue leading to improved adaptation to overnutrition and hypothermia in the offspring.
Project description:<br><br>Annual heart allograft failure in humans rates about 3-5%. The main reason after the first postoperative year is chronic rejection. Myointimal hyperplasia, the hellmark of chronic rejection, results in a specific type of ischemic heart disease. The lack of angina pectoris symptoms allow ventricular arrythmias, sudden cardiac death or heart failure to occur without warning. In addition, diagnostic tools such as endomyocardial biopsy, coronary angiography or intracoronary ultrasound fail to predict the individual risk for myocardial dysfunction.<br><br>The mechanisms responsible for chronic rejection are predominantly alloimmune mediated with activated T cells, macrophages, B cell mediated antibody formation and secreted cytokines responding to HLA and other endothelial cell antigens. In addition, non immunologic risk factors such as recipient age, metabolic factors, hypertension and ischemia contribute to development of this disease. Previous studies have demonstrated that ischemia has a profound influence on short term allograft survival but the underlaying mechanisms remain largely unknown. Apoptosis seems to play a crucial role in ischemia/reperfusion injury and several mechanisms for programmed cell death have been described. However, consequences on long term cell function of viability have not been investigated. <br><br>The aim of this study was to investigate the implication and the mechanism of prolonged cold organ storage as a non immunologic risk factor in the pathogenesis of chronic rejection in a cardiac allograft model. <br><br>We aimed for answering the following specific questions:<br><br>How does cold ischemia affect the alloimmue response short and long term? <br><br>How does prolonged cold ischemia affect gene expression at later time points after transplantation? <br><br>Does it influence gene expression during chronic rejection?<br><br><br><br>
Project description:Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by progressive paralysis resulting from specific degeneration of upper and lower motor neurons (MNs). Chronic neuroinflammation, mediated by activated microglia, is a hallmark of patients diagnosed with ALS, and correlates with disease pathogenesis. Protecting MNs, particularly from toxic insults caused by neuroinflammation, could lead to effective treatments of ALS patient. Here, we report a screening campaign identifying a series of pyrazolotriazines that cell-autonomously protect MNs against neuroinflammation. We demonstrate that these compounds inhibit Cyclin-dependent kinase 5 (CDK5) and Glycogen synthase kinase 3 (GSK3), and we use phospho-proteomics to show that neuroprotection is linked to alterations in microtubule dynamics.
Project description:We applied a deep-sequencing based method – digital gene expression profiling (DGEP), to investigate gene expression in interscapular brown adipose tissue (iBAT), inguinal white adipose tissue (iWAT) and epididymal white adipose tissue (eWAT) in acute cold exposure Examination of gene expression level in 3 different adipose tissues in 3 time points, day0, day2 and day4 in cold exposure.