Biology subjects

Calvano, E.

Publications and source records attributed to Calvano, E..

4 recordsLinked to original sources

bioRxiv2026

Satellite cell glucocorticoid receptor restrains myogenic commitment without mediating the effects of therapeutic glucocorticoids on muscle repair

Glucocorticoids (GCs) exert profound effects on skeletal muscle, but the contribution of satellite cell (SatC) glucocorticoid receptor (GR) signaling to muscle regeneration remains poorly understood. Here, we investigated the role of GR in SatC homeostasis and assessed whether SatC GR mediates the effects of therapeutic GCs on muscle repair. Conditional deletion of GR in SatC reduced the number of PAX7-positive cells during regeneration in young mice, but did not substantially impair muscle repair in either young or aged animals. Transcriptomic and chromatin profiling revealed that GR occupies genes involved in stem cell fate and developmental signaling, with extensive GR binding already established in quiescent SatC. GR-deficient quiescent SatC showed reduced expression of Yap1, Runx1 and Foxo1, together with increased Myog expression. Similarly, GR silencing in human myoblasts induced early myogenic differentiation markers without affecting proliferation, supporting a conserved role for GR in restraining myogenic commitment. We next examined the effects of two therapeutic GCs on muscle regeneration. Chronic prednisone treatment altered the transcriptional landscape of regenerating muscle in an age-dependent manner, without substantially affecting histological repair. In contrast, dexamethasone administration during the early inflammatory phase delayed regeneration, with persistent necrosis and increased collagen deposition. These effects were comparable in control and SatC-specific GR-deficient mice, indicating that they do not require GR in SatC. Together, these findings identify GR as a regulator of the quiescent, undifferentiated state of SatC, while showing that the effects of therapeutic GCs on muscle repair are largely independent of SatC GR. They further highlight the importance of treatment regimen and physiological context in determining the effects of GCs on skeletal muscle regeneration.

physiology↗

bioRxiv2026

Interdependent androgen and glucocorticoid receptor signalling shapes prostate epithelial homeostasis

Androgen signalling is essential for prostate secretory functions and epithelial cell maintenance, yet how this signal is translated into a transcriptional output remains poorly understood. Androgens functions are primarily mediated by the androgen receptor (AR), which binds hormone response elements similar to those of other steroid receptors, including the glucocorticoid receptor (GR). Here we show that AR and GR are co-expressed in the prostate epithelium, and co-located within nuclear foci. Moreover, GR promotes the formation and dynamics of AR nuclear condensates, and heterodimerizes with AR in a ligand-binding domain-dependent manner. In addition, subtle variations within the hormone response element sequence direct the co-recruitment of AR and GR into activator or repressor complexes to activate or repress gene expression. Finally, prostate-specific deletion of GR in mice disrupts AR nuclear distribution, impairs AR-dependent gene networks involved in epithelial maintenance, and promotes the expression of genes involved in metabolism and cell cycle, resulting in altered tissue homeostasis. Thus, these findings identify GR as an integral component of the AR transcriptional machinery in epithelial cells of the healthy prostate, and reveal how shared cis-regulatory elements are interpreted to generate distinct transcriptional outcomes.

cell biology↗

bioRxiv2025

Androgen receptor imprints satellite cells stemness and preserves their reservoir for lifelong regeneration and optimal repair

Skeletal muscle stem cells (MuSC) are the guardians of muscle regeneration, sustaining tissue integrity through a delicate balance of quiescence, activation, and lineage commitment. While numerous molecular cues have been implicated in regulating these processes, the influence of androgen receptor (AR) signaling, an essential hormonal pathway for male muscle physiology, has remained largely unexplored. Here, we show that AR expression defines quiescent MuSC and acts as a safeguard of their dormancy. Integrated multi-omic analyses reveal a redistribution of AR binding from quiescence-maintenance loci to regulatory elements driving activation and metabolic reprogramming during repair. Loss of AR in young adult mice disrupts this balance, precipitating premature cell-cycle entry, skewed division modalities, depletion of the stem cell reservoir, and destabilization of the niche. These defects converge with hallmarks of aging-associated androgen decline, while androgen supplementation restores regenerative competence. Together, our findings establish AR signaling as a pivotal determinant of MuSC fate and a cornerstone of skeletal muscle homeostasis.

developmental biology↗

bioRxiv2025

Glucocorticoid Receptor Signaling in Myeloid Cells Orchestrates Inflammation Resolution and Muscle Repair

Glucocorticoids are key regulators of inflammation and tissue repair, yet their precise role in muscle regeneration remains incompletely understood. Here, we investigate the impact of myeloid-specific glucocorticoid receptor (GR) invalidation on macrophage dynamics and muscle stem cell function following acute injury. We demonstrate that the loss of GR in myeloid cells leads to increased macrophage accumulation, driven by altered proliferation and recruitment, without affecting fibro-adipogenic progenitor differentiation or satellite cell proliferation and differentiation under steady-state conditions. Transcriptomic and cistrome analyses at early regeneration stages reveal that GR directly regulates gene networks involved in efferocytosis and cell cycle control in myeloid cells. Importantly, administration of dexamethasone during the pro-inflammatory phase markedly delays muscle regeneration by impairing monocyte-to-macrophage transition and promoting macrophage proliferation in a myeloid-GR dependent manner, ultimately reducing satellite cell proliferation and myogenesis. In contrast, dexamethasone treatment during the anti-inflammatory phase exerts limited effects on muscle recovery. Together, our findings uncover a critical temporal role of GR signaling in myeloid cells in coordinating inflammatory resolution and stem cell function during muscle repair, and highlight the complexity of glucocorticoid actions in regenerative contexts.

developmental biology↗