BackgroundThe Duffy antigen receptor for chemokines (DARC) shows high affinity binding to multiple inflammatory CC and CXC chemokines and is expressed by erythrocytes and endothelial cells. Recent evidence suggests that endothelial DARC facilitates chemokine transcytosis to promote neutrophil recruitment. However, the mechanism of chemokine endocytosis by DARC remains unclear.Methodology/Principal FindingsWe investigated the role of several endocytic pathways in DARC-mediated ligand internalization. Here we report that, although DARC co-localizes with caveolin-1 in endothelial cells, caveolin-1 is dispensable for DARC-mediated 125I-CXCL1 endocytosis as knockdown of caveolin-1 failed to inhibit ligand internalization. 125I-CXCL1 endocytosis by DARC was also independent of clathrin and flotillin-1 but required cholesterol and was, in part, inhibited by silencing Dynamin II expression. 125I-CXCL1 endocytosis was inhibited by amiloride, cytochalasin D, and the PKC inhibitor Gö6976 whereas Platelet Derived Growth Factor (PDGF) enhanced ligand internalization through DARC. The majority of DARC-ligand interactions occurred on the endothelial surface, with DARC identified along plasma membrane extensions with the appearance of ruffles, supporting the concept that DARC provides a high affinity scaffolding function for surface retention of chemokines on endothelial cells.Conclusions/SignificanceThese results show DARC-mediated chemokine endocytosis occurs through a macropinocytosis-like process in endothelial cells and caveolin-1 is dispensable for CXCL1 internalization.
Background Respiratory failure in severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection appears related to cytokine release syndrome (CRS) that often results in mechanical ventilation (MV). We investigated the role of tocilizumab (TCZ) on interleukin‐6 (IL‐6) trends and MV in SARS‐CoV‐2 patients. Methods In this longitudinal observational study, 112 patients were evaluated from 2/1/2020 ‐ 5/31/2020. TCZ was administered followed by methylprednisolone to patients with > 3L oxygen (O2) requirement and pneumonia severity index (PSI) score ≤ 130 with CT scan changes. IL‐6, C‐reactive protein (CRP), ferritin, lactate dehydrogenase (LDH), D‐dimer, and procalcitonin were monitored on days 0, 3, and 6 of therapy. Statistical analyses were performed with significance ≤ 0.05. Results 80/112 SARS‐CoV‐2‐positive patients (45 males, 56.96%; 34 females, 43.04%) were included in this study. Seven patients expired (8.75%) and nine patients required MV (11.25%). Median IL‐6 levels pre‐administration of TCZ was 342.50 (78.25 ‐ 666.25) pg/mL compared to post‐administration on day 3 (563; 162 ‐ 783) pg/mL ( P < 0.00001). On day 6, the median dropped to 545 (333.50 ‐ 678.50) pg/mL compared to day 3 ( P = 0.709). CRP, ferritin, LDH, and D‐dimer levels were reduced following TCZ therapy. Conclusions Early use of TCZ may reduce the need for MV and decrease CRP, ferritin, LDH, and D‐dimer levels. The sequential use of methylprednisolone for 72 hours seems to potentiate the effect and prolong the suppression of the cytokine storm. IL‐6 levels may be helpful as a prognostic tool. This article is protected by copyright. All rights reserved.
Introduction: RNA isolation from tumor tissue is used for biomarker analyses and validation. Limited diagnostic material from small volume biopsies combined with an increasing demand for standard histologic, molecular characterization, and next generation sequencing applications often leads to limited material for research. We sought to evaluate small volume sampling of lung cancer tissue collected from a single needle pass during a diagnostic procedure and determine if it can provide RNA of acceptable quantity and quality. Methods: We enrolled 140 patients with probable primary bronchogenic carcinoma and collected RNA from a dedicated FNA aspiration. Total RNA (ηg), RNA integrity number (RIN), and %Mass in base pairs were evaluated from each patient sample. A customized nanoString nCounter® 95-gene panel was used to profile the expression patterns of feature NSCLC genes. We compared gene expression patterns that distinguish lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) in our cohort with a corresponding Cancer Genome Atlas (TCGA) NSCLC datasets. Results: Of the 149 patients consented. RNA-extraction was performed in 101 eligible patients. A satisfactory total RNA mass and RIN was quantified for all samples with a similar distribution among cellular subtypes. Mean %-Mass over 300 base pairs was noted for all specimens and 96% of samples met criteria to perform genetic evaluation with our commercialized gene expression assay. The FNA-derived transcriptomic results showed excellent consistency with the TCGA counterparts, and the differential expression pattern of LUAD vs LUSC subtypes were highly similar. Discussion: In this study, RNA retrieval from a single-pass FNA regardless of procedural approach showed equivalence and suitability for gene expression assessments. RNA extraction from small volume samples has the potential to provide valuable material for genetic profiling.
Splenic rupture due to any cause is a life-threatening complication and commonly attributed to trauma. Atraumatic splenic rupture is very rarely reported, and the incidence is currently unknown. Anticoagulants and dual anti-platelet medication can increase the chances of a splenic rupture. Surgical removal of the spleen may be warranted to prevent a life-threatening bleeding. Early identification and intervention are required for most patients as only a few qualify for medical management.
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