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Martino, M. M.

Publications and source records attributed to Martino, M. M..

2 recordsLinked to original sources

Engineered Amphiregulin Promotes Tissue Healing via Dual Regenerative and Immunomodulatory Functions in Tissue-Resident Non-Immune Cells

Amphiregulin (AREG), a growth factor prominently expressed by immune cells, has emerged as an important mediator of tissue healing. However, its therapeutic potential and immunomodulatory effects remain elusive. Here, we engineered an optimized AREG (eAREG) with enhanced signaling and show that it promotes robust skin repair and muscle regeneration in murine models. Beyond its growth factor function, eAREG acts on tissue-resident non-immune cells to suppress inflammation-induced chemokine programs, thereby limiting the recruitment of pro-inflammatory immune cells. We further demonstrate that eAREG constrains chromatin accessibility at regulatory regions of key chemokine genes, revealing an epigenetic mechanism of immune regulation operating within non-immune tissue compartments. Importantly, the regenerative and immunomodulatory effects of eAREG are preserved in diabetic mice with elevated inflammation and impaired healing. Together, these findings identify eAREG as a dual-function regenerative biologic and establish a design principle for regenerative therapies that integrate morphogenic signaling with immunomodulation mediated by tissue-resident cells.

immunology↗

Macrophages provide a transient muscle stem cell niche via NAMPT secretion

Skeletal muscle is paradigmatic of a regenerative tissue that repairs itself via the activation of a resident stem cell1. Termed the satellite cell, these normally quiescent cells are induced to proliferate by ill-defined wound-derived signals2. Identifying the source and nature of these pro-regenerative cues has been hampered by an inability to visualise the complex cellular interactions that occur within the wound environment. We therefore developed a zebrafish muscle injury model to systematically capture satellite cell interactions within the injury site, in real time, throughout the repair process. This analysis identified that a specific subset of macrophages dwells within the injury, establishing a transient but obligate stem cell niche required for stem cell proliferation. Single cell profiling identified specific signals secreted from dwelling macrophages that include the cytokine, Nicotinamide phosphoribosyltransferase (NAMPT/Visfatin/PBEF). Here we show that NAMPT secretion from the macrophage niche is required for muscle regeneration, acting through the C-C motif chemokine receptor type 5 (CCR5) expressed on muscle stem cells. This analysis reveals that along with their well-described ability to modulate the pro-inflammatory and anti-inflammatory phases of wound repair, specific macrophage populations also provide a transient stem cell-activating niche, directly supplying pro-proliferative cues that govern the timing and rate of muscle stem cell-mediated repair processes.

cell biology↗