Debora Mostosi

Effective host defense requires coordinated regulation of immune activation, metabolism, and redox balance, yet how these processes are integrated remains unclear. Here, we identify dipeptidyl peptidase 3 (Dpp3) as a regulator of immune activation thresholds during bacterial infection. Dpp3−/− mice display enhanced resistance to Klebsiella pneumoniae, with early divergence in bacterial burden, improved survival, preserved tissue architecture, and reduced systemic inflammation. Adoptive transfer experiments demonstrate that Dpp3-deficient immune cells are sufficient to confer protection, indicating a cell-intrinsic effect. Mechanistically, Dpp3 deficiency impairs inducible Nrf2 stabilization, resulting in amplified ROS accumulation and enhanced NF-κB–associated responses. Integrated metabolomic, bioenergetic, and proteomic analyses reveal coordinated mitochondrial remodeling and activation of inflammatory signaling networks, consistent with a metabolically primed immune state. Collectively, these findings establish Dpp3 as a systems-level regulator integrating redox control and immunometabolism to calibrate antimicrobial responses during infection.

The gut microbiota plays a pivotal role in maintaining the dynamic balance of intestinal epithelial and immune cells, crucial for overall organ homeostasis. Dysfunctions in these intricate relationships can lead to inflammation and contribute to the pathogenesis of various diseases. Recent findings uncovered the existence of a gut–muscle axis, revealing how alterations in the gut microbiota can disrupt regulatory mechanisms in muscular and adipose tissues, triggering immune-mediated inflammation. In the context of Duchenne muscular dystrophy (DMD), alterations in intestinal permeability stand as a potential origin of molecules that could trigger muscle degeneration via various pathways. Metabolites produced by gut bacteria, or fragments of bacteria themselves, may have the ability to migrate from the gut into the bloodstream and ultimately infiltrate distant muscle tissues, exacerbating localized pathologies. These insights highlight alternative pathological pathways in DMD beyond the musculoskeletal system, paving the way for nutraceutical supplementation as a potential adjuvant therapy. Understanding the complex interplay between the gut microbiota, immune system, and muscular health offers new perspectives for therapeutic interventions beyond conventional approaches to efficiently counteract the multifaceted nature of DMD.