The PDE8A Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population, specifically designed for loss-of-function studies of the PDE8A gene in a human B-lymphocyte model. This heterogeneous pool, derived via CRISPR/Cas9-mediated gene disruption, circumvents clonal selection biases and provides a physiologically relevant system for examining PDE8A-dependent cAMP signaling. The targeted disruption abrogates PDE8A expression, enabling precise interrogation of downstream effector pathways in lymphoblastoid cells.
The host cell line, Raji, is a well-characterized human B-lymphocyte line established from a Burkitt lymphoma patient. These cells harbor Epstein-Barr virus (EBV) episomes, maintaining a lymphoblastoid phenotype with high proliferative capacity. They express B-cell surface markers (e.g., CD19, CD20) and retain functional antigen-presenting machinery, making them a versatile model for studying B-cell receptor signaling, immunoglobulin production, and lymphoma biology. Their EBV-positive status also renders them suitable for examining viral-host interactions that influence cell growth and survival.
PDE8A is a membrane-associated phosphodiesterase that preferentially hydrolyzes cAMP with high affinity, functioning as a key negative regulator of PKA-dependent signaling cascades. Upstream, its activity is governed by receptors such as the B-cell receptor and Gs-coupled GPCRs, as well as cytokines that modulate cAMP synthesis via adenylyl cyclase. Key downstream mediators include PKA, which phosphorylates CREB and other targets; Rap1, a small GTPase implicated in cell adhesion and migration; and MAPK/ERK, which controls proliferation. PDE8A also interacts with AKAPs and ??-arrestin, which scaffold it near PKA and GPCRs, respectively, facilitating localized cAMP degradation. In the knockout model, loss of PDE8A leads to cAMP accumulation, sustained PKA activation, and enhanced CREB phosphorylation, ultimately altering gene expression programs and crosstalk with the MAPK and AKT pathways.
Within Raji B cells, PDE8A-mediated cAMP hydrolysis likely dampens PKA signaling downstream of B-cell receptor engagement and cytokine stimulation, thereby modulating cell proliferation, survival, and differentiation. Disruption of PDE8A unleashes cAMP/PKA activity, which may dysregulate cell-cycle progression and apoptotic checkpoints, potentially contributing to or opposing lymphomagenic processes. This model is particularly valuable for dissecting the intersection between cAMP metabolism and oncogenic pathways in Burkitt lymphoma, as well as for evaluating how enhanced PKA activity affects B-cell effector functions such as antibody secretion and antigen presentation.
Researchers can apply this knockout population to investigate GPCR-mediated cAMP modulation, screen selective PDE8 inhibitors, or profile signaling networks by transcriptomics and phosphoproteomics. Representative assays include cAMP ELISA for direct measurement, PKA activity kits, phospho-CREB flow cytometry, and RNA-seq to map global transcriptional changes. Apoptosis and proliferation can be monitored by flow cytometry using annexin V/PI staining or CFSE dilution. Additionally, co-culture assays with T cells or antigen-presentation studies can elucidate the role of PDE8A in adaptive immunity. Together, these approaches facilitate functional annotation of PDE8A and promote the development of cAMP-modulating therapies. For further information or customized cell solutions, please contact Ascent Research.
