blocking-lymph-flow-by-suturing-afferent-lymphatic-vessels-in-mice

Blocking Lymph Flow by Suturing Afferent Lymphatic Vessels in Mice

Lymphatic vessels are critical in maintaining tissue fluid balance and optimizing immune protection by transporting antigens, cytokines, and cells to ...

Harbin medical university

University of Calgary

Hepatocellular carcinoma (HCC) is the third most common cause of cancer deaths worldwide. miRNAs have been suggested to have important roles in HCC development. The purpose of this study was to determine the role of miR-139-5p in regulation of epithelial-mesenchymal transition (EMT) and metastasis of HCC cells. Expression levels of miR-139-5p in 49 HCC specimens with adjacent tissues and five HCC cell lines were assessed by quantitative RT-PCR. We found that miR-139-5p was down-regulated in 89.7% of the HCC tissue samples and all of the HCC cell lines. In addition, luciferase reporter assays validated direct binding of miR-139-5p to the 3' untranslated region of zinc finger E-box binding homeobox 1 (ZEB1) and ZEB2. Ectopic expression of miR-139-5p suppressed and miR-139-in promoted EMT, migration, and invasion in Hep3B and SMMC7721 cells. Furthermore, over-expression of ZEB1 and ZEB2 ablated the inhibitory effects of miR-139-5p on migration and invasion in HCC cells. Our study indicates that miR-139-5p functions as a suppressor of HCC EMT and metastasis by targeting ZEB1 and ZEB2, and it may be a therapeutic target for metastatic HCC. 

miR-139-5p inhibits epithelial-mesenchymal transition, migration and invasion of hepatocellular carcinoma cells by targeting ZEB1 and ZEB2.

The spatial and temporal Ag distribution determines the subsequent T cell and B cell activation at the distinct anatomical locations in the lymph node (LN). It is well known that LN conduits facilitate small Ag distribution in the LN, but the mechanism of how Ags travel along LN conduits remains poorly understood. In C57BL/6J mice, using FITC as a fluorescent tracer to study lymph distribution in the LN, we found that FITC preferentially colocalized with LN capsule-associated (LNC) conduits. Images generated using a transmission electron microscope showed that LNC conduits are composed of solid collagen fibers and are wrapped with fibroblastic cells. Superresolution images revealed that high-intensity FITC is typically colocalized with elastin fibers inside the LNC conduits. Whereas tetramethylrhodamine isothiocyanate appears to enter LNC conduits as effectively as FITC, fluorescently-labeled Alexa-555-conjugated OVA labels significantly fewer LNC conduits. Importantly, injection of Alexa-555-conjugated OVA with LPS substantially increases OVA distribution along elastin fibers in LNC conduits, indicating immune stimulation is required for effective OVA traveling along elastin in LN conduits. Finally, elastin fibers preferentially surround lymphatic vessels in the skin and likely guide fluid flow to the lymphatic vessels. Our studies demonstrate that fluid or small molecules are preferentially colocalized with elastin fibers. Although the exact mechanism of how elastin fibers regulate Ag trafficking remains to be explored, our results suggest that elastin can be a potentially new target to direct Ag distribution in the LN during vaccine design.

Elastin Shapes Small Molecule Distribution in Lymph Node Conduits.

Lymphatic vessels remove and transport excess interstitial fluid to lymph nodes (LNs) for fluid balance and immune protection. LNs are typically surrounded by perinodal adipose tissue (PAT). However, PAT is a blood vessel-rich but lymphatic-rare tissue; therefore, how excess fluid in PAT is removed remains unclear. Using C57BL/6 mice, fluorescent dye tracing and transmission electron microscopy results suggest that fluid in PAT can travel to the LN via collagen I channels (PAT-LN conduits), merge into a collagen-rich space between the PAT and LN capsule (PAT-LN sinus), and may enter the LN via the LN capsule-associated conduits. This newly identified route of fluid flow allows fluid to enter the draining LN even when the afferent lymphatic vessels are blocked, indicating that fluid trafficking in PAT-LN conduits is not dependent on functional lymphatic vessels. Similar to lymphatic vessels, PAT-LN conduits can deliver Ags to the LN for immune protection. Additionally,  from intradermal or i.v. infection may use PAT-LN conduits to infect PAT and stimulate PAT immune protection. Our studies revealed a new route of material exchange between PAT and the LN. Ag accumulation and bacterial infection in PAT demonstrate that PAT not only provides energy and regulatory factors, but can also directly participate in immune protection, indicating a new immune function of PAT for host immunity.

Yujia Lin

Department of General Surgery,
The Second Affiliated Hospital of Harbin Medical University,
Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University

Harbin medical university

Blocking Lymph Flow by Suturing Afferent Lymphatic Vessels in Mice

Yujia Lin

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of General Surgery,The Second Affiliated Hospital of Harbin Medical University,Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University

Harbin medical university

Blocking Lymph Flow by Suturing Afferent Lymphatic Vessels in Mice

Department of General Surgery,
The Second Affiliated Hospital of Harbin Medical University,
Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University