Project description:Gouty Arthritis (GA) is caused by urate deposition in the joint capsule, cartilage, bone, and surrounding tissues to trigger recurrent attacks of acute joint inflammation. However, the clearance mechanism of urate deposition is still not clear. We aimed to investigate whether lymphatics vessels can drain monosodium and involve in the immune process of GA. Methods: Inguinal lymph nodes (LNs) in 4 normal volunteers and 4 patients with acute flare of GA were examined by ultrasound. Acute and chronic GA flare mouse models were established by intra-footpad administrations of monosodium urate (MSU) for 1 week or 1 month. Mice were treated with VEGFR-3 inhibitor or undergone popliteal lymph node (PLN) excision or PLN macrophage depletion. The severity of foot inflammation, lymphatic draining function, concentration of uric acid (UA), and macrophage population were examined. Macrophages were co-cultured with MSU-treated lymphatic endothelial cells (LECs) and differential gene expression of LECs was assessed by Agilent gene expression microarray. Results: 1) Draining LNs were enlarged in patients with GA flare and GA mouse models. 2) The lymphatic function and structure were abnormal in GA mouse models. 3) Acute GA mice had elevated UA levels in draining LNs, but not in the serum, while chronic GA mice had elevated UA levels in both LNs and serum. 4) Blockade of VEGFR-3 reduced foot inflammation in chronic GA mice. 5) MSU induces pro-inflammatory polarization of macrophages by inducing LEC inflammation. 6) PLN local depletion of macrophages or removal of PLNs alleviated foot inflammation in GA. Conclusions: Lymphatics drain MSU to the draining LNs to clear deposited urate in the distal extremity and induce LECs to stimulate macrophage pro-inflammatory response during GA. We have identified a novel mechanism about MSU clearance and pro-inflammatory macrophage activation, and provided possible therapeutic approach for GA.
Project description:Aim of the study was to characterize at a molecular level (changes in transcriptomes) the effect of monosodium urate crystal (MSU) on HaCaT keratinocyte cell line. This was adressed by using a culture model. The HaCaT cell line (human keratinocytes) was stimulated by MSU (1mg/mL) vs control for 12 hrs. By using genome-wide expression profiling, we identified deregulation of functionally relevant gene networks.
Project description:We used I-BET 151, an isoxazoloquinoline that specifically inhibits interaction of BET proteins with acetylated histones to restrict inflammatory tissue priming in a mouse model of iterated monosodium urate (MSU) crystal-induced arthritis. Systemic administration of I-BET 151 abolished the enhancement of arthritis upon repeated injection of MSU crystals.
Project description:Lymphogenous metastasis is an important event in the progression of many human cancers, and is associated with expression of vascular endothelial growth factor-D (VEGF-D). Changes to the lymphatic vasculature can occur during metastasis, and may aid metastatic spread. We investigated the effect of tumour derived VEGFD on the endothelium of the collecting lymphatic vessels draining primary tumors. We used microarrays to detail the changes in gene expression in the collecting lymphatic endothelium of mice with 293EBNA xenografts compared to 293EBNA xenografts overexpressing VEGFD. Mice were injected with 293EBNA cells (transfected with either empty APEX vector, or vector containing VEGFD) and tumours were allowed to grow to size. Mice were sacrificed and collecting lymphatic vessels were dissected. The endothelial cell population was isolated and RNA was extracted and hybridized on Affymetrix microarrays.
Project description:Aim of the study was to characterize at a molecular level (changes in transcriptomes) the effect of monosodium urate crystal (MSU) on HaCaT keratinocyte cell line. This was adressed by using a culture model. The HaCaT cell line (human keratinocytes) was stimulated by MSU (1mg/mL) vs control for 12 hrs. By using genome-wide expression profiling, we identified deregulation of functionally relevant gene networks. HaCaT were obtained from Cell Lines Service (Eppelheim, Germany) and grown in DMEM medium (PAN biotech, Aidenbach, Germany) supplemented with 10% FBS (Life Technology, Grand Island, NY, USA), L-glutamine and non-essential amino acid. Before the treatment HaCaT cells were cultured in serum-free medium for 12hrs. HaCaT were treated with MSU (1mg/ml) vs DMEM control for 12hrs then submitted to RNA extration and gene expression profiling. Triplicate experiments were performed: HaCaT control (n=3), MSU-treated (n=3).
Project description:Lymphogenous metastasis is an important event in the progression of many human cancers, and is associated with expression of vascular endothelial growth factor-D (VEGF-D). Changes to the lymphatic vasculature can occur during metastasis, and may aid metastatic spread. We investigated the effect of tumour derived VEGFD on the endothelium of the collecting lymphatic vessels draining primary tumors. We used microarrays to detail the changes in gene expression in the collecting lymphatic endothelium of mice with 293EBNA xenografts compared to 293EBNA xenografts overexpressing VEGFD.
Project description:Objective. To identify novel monosodium urate (MSU) crystal-induced mRNAs by transcript profiling of isolated murine air pouch membranes. Methods. Nine hours after injecting crystals into air pouches, membranes were meticulously dissected away from the adjacent soft tissues. mRNA expression differences between inflamed and control membranes were determined by oligonucleotide microarray analysis. Induction of selected mRNAs was validated by real-time relative quantitative reverse transcriptase PCR (qPCR) in pouch membranes and murine peritoneal macrophages. Results. Eleven of the 12 most highly upregulated mRNAs related to innate immunity and inflammation. They included mRNAs encoding histidine decarboxylase (the enzyme that synthesizes histamine), interleukin (IL)-6, the cell surface receptors PUMA-g and TREM-1, and the polypeptides Irg1 and PROK-2. MSU crystals induced dramatic rises in these mRNAs in the pouch membrane within 3-8 hours after the surge in pro-inflammatory cytokine (IL-6, IL-1beta and TNFalpha) and immediate early gene (Egr-1) transcription, which occurred 1h after crystal injection. MSU crystals induced these mRNAs in cultured macrophages with similar kinetics but lower fold changes. In keeping with their downregulation by MSU crystals according to the microarrays, qPCR confirmed that TREM-2 and granzyme D mRNAs decreased 79% and 94%, respectively, in MSU crystal inflamed membranes. Conclusions. This analysis disclosed several genes previously not implicated in MSU crystal inflammation. Their rise after the early surge in cytokine mRNAs suggests that they may, for instance, amplify or perpetuate inflammation. Transcript profiling of the isolated air pouch membrane promises to be a powerful tool to identify genes acting at different stages of inflammation.
Project description:The lineage and developmental trajectory of a cell are key determinant s of cellular identity. In the vascular system, endothelial cells (ECs) of blood and lymphatic vessels (LVs) differentiate and diversify to cater the different physiological demands of each organ . While LVs are known to originate from multiple origins , lymphatic ECs (LECs) themselves are not known to generate other cell - types . Here, we u s e recurrent imaging and lineage - tracing of ECs in zebrafish anal fins (AF) from early development through adulthood , to uncover an unexpected mechanism of specialized blood vessel formation through transdifferentiation of LECs . Moreover, we demonstrate distinct functional implications for deriving AF vessels from either LECs or blood ECs, uncovering a link between cell ontogeny and functionality. We further use scRNA - seq to characterize the different cellular populations and transition states involved in the transdifferentiation process . Finally, we show that akin to its normal development, the vasculature is re - derived from lymphatics during AF regeneration, demonstr ating that LECs in adult fish retain both potency and plasticity for generating blood ECs . Overall, our work highlights a new innate mechanism of blood vess el formation through LEC trans differentiation, and provides in vivo evidence for a link between cell ontogeny and functionality in ECs