Intestinal epithelial cells (IECs) maintain gut epithelial homeostasis and barrier integrity through rapid, continuous renewal. Tight control of proliferation is mediated by a complex network of cell-cycle regulators and effectors. Dysregulation of cell-cycle pathways is a hallmark of colorectal cancer development and progression.
JDP2 (Jun dimerization protein 2) has been implicated in cell-cycle control and associated with diverse cancers. Depending on cellular and disease context, JDP2 can act as a transcription factor or an epigenetic regulator. Prior to this study, the role of JDP2 specifically in colorectal cancer (CRC) and in maintaining cell-cycle homeostasis in colon-derived epithelial cells was not well defined.
The investigators depleted JDP2 in colorectal epithelial cells and assayed proliferative and mitotic markers. JDP2 depletion led to increased EdU incorporation during S phase and elevated PHH3 abundance. These functional readouts are consistent with augmented proliferative and mitotic activity after loss of JDP2.
Details such as exact cell lines, experimental timing, knockdown efficiency, or other assay parameters were not reported in the source beyond these outcome measures.
To resolve cell-state changes at high resolution, the authors applied single-cell RNA sequencing (scRNA-seq) to JDP2-depleted and control colorectal epithelial cells. The single-cell transcriptomic analysis revealed reprogramming of cell-cycle-associated transcriptional states following JDP2 depletion.
The scRNA-seq data allowed assignment of cells to transcriptional states along canonical cell-cycle phases and identification of shifts in state occupancy after JDP2 knockdown. Specific experimental details for sequencing depth, platform, or number of cells captured were not provided in the source text.
Differential-expression and pathway analyses identified altered expression in genes and programs related to mitosis and cell-cycle regulation. Affected categories included cyclins, cyclin-dependent kinases, genes involved in chromosome segregation, and regulators of mitotic progression. These changes align with the functional finding of increased S-phase incorporation and mitotic marker abundance.
The source did not enumerate individual gene names beyond these program-level descriptions, nor did it report exact fold-changes or p-values for the gene-level results except for aggregated observations reported elsewhere in the study.
Trajectory analysis along a G1 → S → G2/M transcriptional axis demonstrated that lower residual JDP2 expression was associated with increased representation in G2/M-related transcriptional states and with transitions toward later states along this trajectory.
Quantitatively, cells classified as low-JDP2 occupied late transcriptional states at a higher frequency than high-JDP2 cells: 33.6% versus 24.0%, with a paired P value reported as 0.048 in the source. This observation supports a model in which reduced JDP2 biases cell populations toward later cell-cycle phases.
Within the population of JDP2-siRNA-treated cells, a subset retained residual JDP2 expression. Analysis of these residual-expressing cells revealed heterogeneous associations of JDP2 with transcriptional programs tied to cell-cycle regulation, survival, apoptosis, and stress responses. The authors interpret these findings as consistent with context-dependent, pleiotropic transcriptional functions of JDP2.
The source did not provide additional mechanistic dissection of how residual JDP2 expression drives these divergent program associations.
Together, the reported functional assays and single-cell transcriptomics identify JDP2 as an important component of intestinal epithelial cell-cycle homeostasis and transcriptional landscape. Depletion of JDP2 perturbs the balance of proliferative cell states, increasing S-phase and G2/M-associated states and altering expression of mitotic and cell-cycle regulatory programs.
The authors also report a clinical association: patients with higher JDP2 expression had significantly worse survival than those with lower expression. The source did not provide detailed cohort parameters or survival-analysis methods in the text provided here.
Implications include the potential relevance of JDP2 to colorectal tumor biology through effects on proliferation and mitotic programs, but further mechanistic and in vivo validation were not described in the available source content.
The work reported funding from the National Institute of General Medical Sciences (5P20GM130456-07; Alam Project ID 9180), the National Institute of Diabetes and Digestive and Kidney Diseases (R56DK136728 and K01DK114391), the American Cancer Society Institutional Research Grant (ACS IRG), and the Elsa U. Pardee Foundation Grant, as declared by the authors.
The authors declared no competing interests.