A predominantly glial origin of axonal ribosomes after nerve injury

• Published in: Glia Vol. 66; no. 8; pp. 1591 - 1610
• Main Authors: Müller, Kerstin, Schnatz, Andrea, Schillner, Miriam, Woertge, Simone, Müller, Christina, von Graevenitz, Ilse, Waisman, Ari, van Minnen, Jan, Vogelaar, Christina F.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.08.2018
• Subjects: Animals; axon; Axonal transport; Axons; Axons - metabolism; Dorsal root ganglia; Ganglia; Ganglia, Spinal - metabolism; Glial cells; Injuries; Mice, Transgenic; mRNA; Nerve Regeneration - physiology; Neuroglia - metabolism; Peripheral Nerve Injuries - metabolism; Peripheral Nerve Injuries - pathology; Protein biosynthesis; Protein synthesis; Protein transport; Proteins; Regeneration; Ribosomal DNA; Ribosomal protein L4; ribosome; Ribosomes; RNA transport; Rodents; Schwann cell; Schwann cells; Schwann Cells - metabolism; Sciatic nerve; Sciatic Nerve - metabolism; transfer; transgenic; Transgenic mice; ribosome; transgenic; transfer; axon; Schwann cell
• ISSN: 0894-1491; 1098-1136
• DOI: 10.1002/glia.23327

Axonal mRNA transport and local protein synthesis are crucial for peripheral axon regeneration. To date, it remains unclear how ribosomes localize to axons. They may be co‐transported with mRNAs or, as suggested by recent studies, transferred from Schwann cells (SC). Here, we generated transgenic “RiboTracker” mice expressing tdTomato‐tagged ribosomal protein L4 in specific cell types when crossed with Cre lines. Two neuronal RiboTracker‐Cre lines displayed extremely low levels of axonal L4‐tdTomato‐positive ribosomes. In contrast, two glial RiboTracker‐Cre lines revealed tagged ribosomes in sciatic nerve (SN) axons with increasing amounts after injury. Furthermore, non‐RiboTracker dorsal root ganglia co‐cultured with L4‐tdTomato‐expressing SCs displayed tagged ribosomes in axons. These data provide unequivocal evidence that SN axons receive ribosomes from SCs upon injury and indicate that glial cells are the main source of axonal ribosomes. Main Points The “RiboTracker” mouse allows in vivo tracking of the origin of axonal ribosomes. Ribosomes are transferred from Schwann cells to axons in culture. Sciatic nerve injury increases axonal localization of predominantly Schwann cell‐derived ribosomes.