Human Lymph Node Derived Fibroblastic Reticular Cells and Their Chemokine Expression Profile After an Inflammatory Stimulus

Abstract

Lymph node is a secondary lymphoid organ with highly organized and compartmentalized structure. Fibroblastic reticular cells (FRC) integrate LN structure, and are characterized by podoplanin expression (PDPN) and lack of CD31. FRCs are involved in several immune response processes but the mechanism is still under investigation. Another cell population present in the lymph node is the one lacking PDPN and CD31, so called, double negative population (DNC). FRCs and DNCs are described as chemokines producers, controlling migratory pattern and positioning of immune cells during homeostasis or inflammation. We evaluate the gene expression of human FRCs and DNCs after an inflammatory stimulus. Lymph nodes were obtained from 04 patients with different clinical diagnosis submitted to surgical procedures. All patients signed an informed consent (Approved by Ethic Committee - CAAE: 07768712.4.0000.0071). All lymph nodes were analyzed by histopathology, they were also enzymatic digested. Cells were characterized and sorted in two populations FRCs and DNCs. These cells were maintained without stimuli or stimulated with TNFα + IL-1β for 24hours. Next, RNA was extracted; gene expression was characterized using DNA Microarray. Our results demonstrate up-regulation of chemokines such as CCL2, CCL3, CCL5, CCL7 CXCL1, CXCL2, CXCL8 and CXL10 (p<0.05) in both cells subsets after inflammatory stimuli, the secretion enhancement of CCL2, CCL20 and CXCL8 was confirmed by ELISA. The up-regulated expression of CCL3L3, CCL11, CCL13, CXCL5, CXCL6 only by FRCs and CCL8, CXCL3 only by DNCs, may link these cells to additional properties that need to be further investigated. These results show that FRC and DNC positively respond to an inflammatory stimulus.