TY - JOUR TI - Spatial transcriptomics reveals metabolic changes underly age-dependent declines in digit regeneration AU - Tower, Robert J AU - Busse, Emily AU - Jaramillo, Josue AU - Lacey, Michelle AU - Hoffseth, Kevin AU - Guntur, Anyonya R AU - Simkin, Jennifer AU - Sammarco, Mimi C A2 - Ackert-Bicknell, Cheryl A2 - Cheah, Kathryn Song Eng VL - 11 PY - 2022 DA - 2022/05/26 SP - e71542 C1 - eLife 2022;11:e71542 DO - 10.7554/eLife.71542 UR - https://doi.org/10.7554/eLife.71542 AB - De novo limb regeneration after amputation is restricted in mammals to the distal digit tip. Central to this regenerative process is the blastema, a heterogeneous population of lineage-restricted, dedifferentiated cells that ultimately orchestrates regeneration of the amputated bone and surrounding soft tissue. To investigate skeletal regeneration, we made use of spatial transcriptomics to characterize the transcriptional profile specifically within the blastema. Using this technique, we generated a gene signature with high specificity for the blastema in both our spatial data, as well as other previously published single-cell RNA-sequencing transcriptomic studies. To elucidate potential mechanisms distinguishing regenerative from non-regenerative healing, we applied spatial transcriptomics to an aging model. Consistent with other forms of repair, our digit amputation mouse model showed a significant impairment in regeneration in aged mice. Contrasting young and aged mice, spatial analysis revealed a metabolic shift in aged blastema associated with an increased bioenergetic requirement. This enhanced metabolic turnover was associated with increased hypoxia and angiogenic signaling, leading to excessive vascularization and altered regenerated bone architecture in aged mice. Administration of the metabolite oxaloacetate decreased the oxygen consumption rate of the aged blastema and increased WNT signaling, leading to enhanced in vivo bone regeneration. Thus, targeting cell metabolism may be a promising strategy to mitigate aging-induced declines in tissue regeneration. KW - digit regeneration KW - aging KW - cell metabolism KW - bone regeneration KW - spatial transcriptomics KW - oxaloacetate JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -