miRNA-Mediated Regulation of Gene Expression During Early Activation in Jurkat Cells.

BACKGROUND

T cell activation induces substantial changes in gene expression by rapidly increasing transcription and translation. Additionally, microRNAs play a crucial role in regulating protein expression in T cell physiology, adding a layer of complexity by fine-tuning protein levels. While various miRNAs have been implicated in T cell function, a systematic analysis of differentially expressed miRNAs during early T cell activation and identification of their mRNA targets remains mostly unknown.

RESULTS

We investigated dynamic changes in global gene expression during early T cell activation using a multi-omics approach combining small RNA-seq, mRNA-seq and ribosome profiling. Our results show that most differential expression changes occur by 5 hours postactivation, with translational upregulation predominating over downregulation. From 5 to 12 hours, we observed modest transcriptional and translational reprogramming. We identified 9 miRNAs that are differentially expressed (DE) during early activation, with most changes occurring as early as 5 hours. We calculated translation efficiency (TE) and classified genes based on changes in both mRNA abundance and ribosome-protected fragments (RPFs). By integrating TE and miRNA expression data, we examined the relationship between TE group-specific regulation patterns and the number of miRNA binding sites. Interestingly, rather than observing a uniform downregulation of targets with 4 or more predicted DE miRNA binding sites, we found distinct regulatory patterns that varied with both activation time point and TE category.

CONCLUSIONS

Our data provide new insights into how genes associated with key events in T cell activation such as translation, cell proliferation, and immune signaling are regulated at both the transcriptional and translational levels. The observation that most regulatory changes occur within the first 5 hours post-activation highlights the rapid and coordinated nature of T cell responses. The differential patterns of target regulation, based on translation efficiency groups and miRNA binding site density, suggest a context-dependent role for miRNAs in shaping protein output. Future experiments will be required to functionally validate specific miRNA-target interactions and to explore their relevance in primary T cells . This study also lays the groundwork for identifying miRNA-based regulatory circuits for therapeutic modulation of T cell activity.