Biology subjects

Reyes-Ordonez, A.

Publications and source records attributed to Reyes-Ordonez, A..

3 recordsLinked to original sources

bioRxiv2026

Loss of LanC-like proteins impairs post-injury regeneration of aging muscles

The adult skeletal muscle regenerates robustly upon injury, but this regenerative capacity rapidly declines with age. In this study, we identify the lanthionine synthetase C-Like (LanCL) proteins, mammalian homologs of the bacterial peptide cyclase LanC, as positive regulators of muscle regeneration in middle-aged mice. In a barium chloride-induced injury model, we found the protein levels of LanCL1 and LanCL2 to increase during an early phase of regeneration in middle-aged (12-month-old) but not young adult (4-month-old) mice. Utilizing a mouse line lacking all three LanCL proteins (LanCL triple KO or LTKO), we examined a potential role of LanCL in injury-induced muscle regeneration. Consistent with an age-dependent function of LanCL, we observed a delayed regeneration of the tibialis anterior (TA) muscle after injury, as reflected by reduced sizes of regenerating myofibers in middle-aged (but not young) LTKO compared to age-matched WT mice. Although the pool size of quiescent satellite cells (Pax7+) was comparable between 12-month-old LTKO and WT muscles without injury, the number of Pax7+ cells was significantly higher in regenerating LTKO muscles at day 5 after injury, accompanied by drastically decreased numbers of MyoD+ and MyoG+ cells, as well as increased numbers of proliferating cells. In addition, we detected elevated expression of pro-inflammatory cytokines in regenerating LTKO muscles, while the number of macrophages was similar comparing LTKO and WT muscles. Taken together, our observations suggest that in aging muscles LanCLs are important for proper timing of inflammation resolution and regeneration upon injury.

physiology↗

bioRxiv2020

Redefining the specificity of phosphoinositide-binding by human PH domain-containing proteins

Pleckstrin homology (PH) domains are presumed to bind phosphoinositides (PIPs), but specific interaction with and regulation by PIPs for most PH domain-containing proteins are unclear. Here we employed a single-molecule pulldown assay to study interactions of lipid vesicles with full-length proteins in mammalian whole cell lysates. Of 67 human PH domaincontaining proteins examined, 36 (54%) were found to have affinity for PIPs with various specificity, the majority of which had not been reported before. Further investigation of ARHGEF3 revealed structural requirements and functional relevance of its newly discovered PI(4,5)P2 binding. A recursive-learning algorithm based on the assay results of the 67 proteins was generated to analyze the sequences of 246 human PH domains, which predicted 48% of them to bind PIPs. A collection of the predicted PIP-binding proteins was assayed, with the vast majority found to bind PIPs. Collectively, our findings reveal unexpected lipid-binding specificity of PH domain-containing proteins.

biochemistry↗

bioRxiv2020

ARHGEF3 regulates skeletal muscle regeneration and strength through autophagy

Skeletal muscle regeneration is essential for restoring muscle function upon injury and for the maintenance of muscle health with aging. ARHGEF3, a Rho-specific GEF, negatively regulates myoblast differentiation via mammalian target of rapamycin complex 2 (mTORC2)-Akt signaling in a GEF-independent manner in vitro. Here, we investigated ARHGEF3s role in skeletal muscle regeneration by creating ARHGEF3 KO mice. These mice exhibited no discernible phenotype under normal conditions. Upon injury, however, ARHGEF3 deficiency enhanced the mass, fiber size and function of regenerating muscles in both young and aged mice. Surprisingly, these effects were not mediated by mTORC2-Akt signaling, but by the GEF activity of ARHGEF3. Furthermore, ARHGEF3 KO promoted muscle regeneration through activation of autophagy, a process that is also critical for maintaining muscle strength. Accordingly, in old mice, ARHGEF3 depletion prevented muscle weakness by restoring autophagy flux. Collectively, our findings identify an unexpected link between ARHGEF3 and autophagy-related muscle pathophysiology.

cell biology↗