| First Author | Katoku-Kikyo N | Year | 2023 |
| Journal | PLoS Biol | Volume | 21 |
| Issue | 12 | Pages | e3002419 |
| PubMed ID | 38048364 | Mgi Jnum | J:343507 |
| Mgi Id | MGI:7566793 | Doi | 10.1371/journal.pbio.3002419 |
| Citation | Katoku-Kikyo N, et al. (2023) The circadian regulator PER1 promotes cell reprogramming by inhibiting inflammatory signaling from macrophages. PLoS Biol 21(12):e3002419 |
| abstractText | Circadian regulation of gene expression is prevalent and plays critical roles in cell differentiation. However, its roles in the reprogramming of differentiated cells remain largely unknown. Here, we found that one of the master circadian regulators PER1 promoted virus-mediated reprogramming of mouse embryonic fibroblasts (MEFs) to induced neurons (iNs) and induced pluripotent stem cells (iPSCs). Unexpectedly, PER1 achieved this by repressing inflammatory activation of contaminating macrophages in the MEF culture, rather than by directly modulating the reprogrammability of MEFs. More specifically, we found that transduced viruses activated inflammatory genes in macrophages, such as Tnf encoding TNFalpha, one of the central inflammatory regulators and an autocrine activator of macrophages. TNFalpha inhibited iN reprogramming, whereas a TNFalpha inhibitor promoted iN reprogramming, connecting the inflammatory responses to iN reprogramming. In addition, macrophages were induced to proliferate and mature by non-macrophage cells serving as feeders, which also supported up-regulation of TNFalpha in macrophages without virus transduction. Furthermore, the 2 inflammatory responses were repressed by the circadian regulator PER1 in macrophages, making reprogrammability dependent on time-of-day of virus transduction. Similar results were obtained with iPSC reprogramming, suggesting a wide occurrence of macrophage-mediated inhibition of cell reprogramming. This study uncovers mechanistic links between cell reprogramming, bystander inflammatory macrophages, and circadian rhythms, which are particularly relevant to in vivo reprogramming and organoid formation incorporating immune cells. |
