The eIF4EBP-eIF4E axis regulates CD4+ T cell differentiation through modulation of T cell activation and metabolism

CD4⁺ T cells are critical for adaptive immunity, differentiating into distinct effector and regulatory subsets. Although the transcriptional programs underlying their differentiation are known, recent research has highlighted the importance of mRNA translation in determining protein abundance. We previously conducted genome-wide analysis of translation in CD4⁺ T cells revealing distinct translational signatures distinguishing these subsets, identifying eIF4E as a central differentially translated transcript. As eIF4E is vital for eukaryotic translation, we examined how altered eIF4E activity affected T cell function using mice lacking eIF4E-binding proteins (BP^-/-). BP^-/- effector T cells showed elevated Th1 responses ex vivo and upon viral challenge with enhanced Th1 differentiation observed in vitro. This was accompanied by increased TCR activation and elevated glycolytic activity. This study highlights how regulating T cell-intrinsic eIF4E activity can influence T cell activation and differentiation, suggesting the eIF4EBP-eIF4E axis as a potential therapeutic target for controlling aberrant T cell responses.

scFv-oligopeptide chaperoning system-assisted on-column refolding and purification of human muscle creatine kinase from inclusion bodies

The formation of inclusion bodies in bacterial hosts poses a major challenge for the large-scale recovery of bioactive proteins. The process of obtaining bioactive protein from inclusion bodies is labor intensive, and the yields of recombinant protein are often low. Here, we describe a novel method for the renaturation and purification of inclusion bodies. This method combines a scFv-oligopeptide chaperoning system and an on-column refolding system to help refold human muscle creatine kinase (HCK) inclusion bodies. This method could significantly increase the activity recovery of denatured HCK inclusion bodies and provides an effective method for the production of bioactive proteins from inclusion bodies.

Dynamics of prion proliferation under combined treatment of pharmacological chaperones and interferons

Prions are proteins that cause fatal neurodegenerative diseases. The misfolded conformation adopted by prions can be transmitted to other normally folded proteins. Therapeutics to stop prion proliferation have been studied experimentally; however, it is not clear how the combination of different types of treatments can decrease the growth rate of prions in the brain. In this article, we combine the implementation of pharmacological chaperones and interferons to develop a novel model using a non-linear system of ordinary differential equations and study the quantitative effects of these two treatments on the growth rate of prions. This study aims to identify how the two treatments affect prion proliferation, both individually and in tandem. We analyze the model, and qualitative global results on the disease-free and disease equilibria are proved analytically. Numerical simulations, using parameter values from in vivo experiments that provide a pharmaceutically important demonstration of the effects of these two treatments, are presented here. This mathematical model can be used to identify and optimize the best combination of the treatments within their safe ranges.

Designing an Antibody-Based Chaperoning System through Programming the Binding and Release of the Folding Intermediate

The protein folding pathway consists of sequential intramolecular interactions, while chaperones exert their functions either by stabilizing folding intermediates or by preventing nonspecific intermolecular interactions, which are often associated with aggregation involving exposed hydrophobic residues in folding intermediates. As chaperones do not possess specificity for individual client proteins, we designed an antibody-based chaperoning system to mimic the sequential binding and release of client proteins undergoing folding. The single-chain variable fragment of antibody (scFv) A4 binds to human muscle creatine kinase (HCK) and prevents it from aggregating. The slow dissociation of HCK from A4 resulted in delayed but eventually high-quality refolding, as reflected by the higher recovery of enzymatic activity as well as abolished aggregation. Peptide P6, a sequence in HCK involved in A4 binding, competes with HCK, promotes its dissociation from A4, and accelerates the rate of high-quality refolding. The sequential addition of A4 and P6 is essential for the chaperoning effect. The programmed binding/release method can also be applied to refold HCK from inclusion bodies. Because the association/dissociation of the folding intermediate with the antibody is highly specific, the method can be used to design tailored refolding systems and to investigate chaperoning effects on protein folding/aggregation in a sequence-specific manner.