Transcriptomic analysis of early B-cell development in the chicken embryo

Abstract

The chicken bursa of Fabricius is a primary lymphoid tissue important for B-cell development. Our long-term goal is to understand the role of bursal microenvironment in an early B-cell differentiation event initiating repertoire development through immunoglobulin gene conversion in the chick embryo. We hypothesize that early bursal B-cell differentiation is guided by signals through cytokine receptors. Our theory is based on previous evidence for expression of the receptor tyrosine kinase superfamily members and interleukin receptors in unseparated populations of bursal B-cells and bursal tissue. Knowledge of the expressed genes that are responsible for B-cell differentiation is a prerequisite for understanding the bursal microenvironment's function. This project uses transcriptomic analysis to evaluate gene expression across early B-cell development. RNA-seq was performed with total RNA isolated from bursal B-cells at embryonic day (ED) 16 and ED 19 (n = 3). Approximately 90 million high-quality clean reads were obtained from the cDNA libraries. The analysis revealed differentially expressed genes involved in the Jak-STAT pathway, Wnt signaling pathway, MAPK signaling pathway, metabolic pathways including tyrosine metabolism, Toll-like receptor signaling pathway, and cell-adhesion molecules. The genes predicted to encode surface receptors, signal transduction proteins, and transcription factors identified in this study represent gene candidates for controlling B-cell development in response to differentiation factors in the bursal microenvironment.

Physiological crosstalk between the Mel1a and Mel1c pathways modulates melatonin-mediated, monochromatic light combination-induced bursa B-lymphocyte proliferation in chickens

“…This result is consistent with the previous report that Mel1a response is Gi-dependent in NS-1 cells [42], Chinese hamster ovary cells [43], and human embryonic kidney cells [44]. Over the years, the AKT/GSK-3β/β-catenin signaling is essential for B-cell survival and development in the bursa [45]. In our study, we found that G→B and B→G signi cantly promoted AKT, GSK-3β and β-catenin phosphorylation compared with WW, RR, GG, BB, and R→B.…”

A Green and Blue Monochromatic Light Combination Therapy Reduces Oxidative Stress and Enhances B‐Lymphocyte Proliferation through Promoting Melatonin Secretion

“…This result is consistent with the previous report that Mel1a response is Gi-dependent in NS-1 cells [ 46 ], Chinese hamster ovary cells [ 47 ], and human embryonic kidney cells [ 48 ]. Over the years, AKT/GSK-3 β / β -catenin signaling is essential for B cell survival and development in the bursa [ 49 ]. In our study, we found that G→B and B→G significantly promoted AKT, GSK-3 β , and β -catenin phosphorylation compared with WW, RR, GG, BB, and R→B.…”

Blocking of the CXCR4-CXCL12 Interaction Inhibits the Migration of Chicken B Cells Into the Bursa of Fabricius

“…We analyzed the expression of the CXCR4 chemokine receptor on the surface of the migrating B cells. The CXCR4 presence has been previously analyzed in the embryonic spleen and bursa (18,21). An increase of the CXCR4 expression was observed in the bursa during the colonization period (26).…”

“…The same chemokine receptor and ligand have been shown to be key players in many other migration processes, including the mobilization of mammalian hematopoietic stem cells, lymphocytes (14)(15)(16) but also primordial germ cells (17). CXCR4 and its ligand CXCL12 are both expressed in chickens during B cell development (18)(19)(20)(21). It has been suggested that immature B cells might also migrate toward the bursa under the influence of the CXCR4/CXCL12 interaction.…”