Makuyana, N. | bioRxiv Science

bioRxiv2025

Immune cell de novo steroidogenesis regulates inflammation resolution and recovery in acute lung injury

Effective resolution of inflammation following acute lung infection or injury is critical for restoring immune and tissue homeostasis to ensure functional recovery. Prolonged or unresolved inflammation can impair lung repair, promote fibrosis, and contribute to pulmonary dysfunction. While systemic steroid signalling is known to modulate general immune responses, the specific role of immune cell-mediated steroidogenesis in regulating lung inflammation and repair remains unknown. Here, we show that immune cell de novo steroidogenesis is essential for resolving inflammation and promoting recovery in a murine model of acute lung injury. During the resolution phase, steroid-synthesizing immune cells, predominantly basophils, are enriched in the lung. Mice with immune cell-specific ablation of de novo steroidogenesis exhibit exacerbated lung injury, impaired resolution of inflammation, and defective tissue repair. These findings reveal a previously unrecognized immunoregulatory function of immune cell-derived steroids and identify immune cell steroidogenesis as a potential therapeutic target for promoting resolution and recovery in inflammatory lung diseases.

immunology↗

bioRxiv2024

Directed disruption of IL2 aggregation sites produces designer biologics with enhanced specificity coupled to improved production capacity

The pleotropic nature of interleukin-2 (IL2) has allowed it to be used as both a pro-inflammatory and anti-inflammatory therapeutic agent, through promotion of regulatory T cell (Treg) responses via the IL2RA receptor or promotion of CD8 T cell responses via the IL2RB receptor, respectively. However, the utility of IL2 as a treatment is limited by this same pleiotropy, and protein engineering to bias specificity towards either the regulatory T cell (Treg) or CD8 T cell lineage often requires a trade-off in protein production or total bioactivity. Here we use SolubiS, a computational algorithm-based method, to predict mutations within the IL2 structure to improve protein production yield while altering cellular selectivity, to generate a mutein with elevated therapeutic potential. The design and testing process identified the V126R (murine) / V111R (human) mutation as a Treg-enhancing mutein, creating a cation repulsion to inhibit primary binding to IL2RB, with a post-IL2RA confirmational shift enabling secondary IL2RB binding, and hence allowing the trimeric receptor complex to form. In human IL2, additional N110R T151R aggregation-protecting mutations could improve protein yield of the V111R mutation. The approach also generated novel CD8 T cell-promoting mutations. Y79K created a cation-cation repulsion with IL2RA, while Q50W enhanced CD8 T cell activity through potential {pi}-stacking enhancing binding to IL2RB, with the combination highly stimulatory for CD8 T cells. For human IL2, Y65K (homolog to murine Y79K) coupled with E82K prevented IL2RA binding, however it required the aggregation-protecting mutations of N110R T151R to rescue production. These muteins, designed with both cellular specificity and protein production features, have potential as both biological tools and therapeutics.

immunology↗