LOTUS suppresses axon growth inhibition by blocking interaction between Nogo receptor-1 and all four types of its ligand
Introduction
Neurons fail to re-elongate damaged axons to their original targets in the adult central nervous system (CNS). This failure has been ascribed to repulsive axon guidance molecules (Niclou et al., 2006) and axonal growth inhibitory molecules in the glial scar (Yiu and He, 2006) and in myelin (Schwab, 2010, Yiu and He, 2006). Among these obstacles, the molecular mechanism underlying myelin-associated inhibition of axonal growth has been investigated most extensively (Schwab, 2010, Yiu and He, 2006). Nogo proteins (GrandPré et al., 2000), myelin-associated glycoprotein (MAG) (McKerracher et al., 1994), and oligodendrocyte myelin glycoprotein (OMgp) (K.C. Wang et al., 2002) have been identified as the major inhibitors of axonal growth in myelin. Nogo receptor-1 (NgR1) is the common receptor for all of these axonal growth inhibitors (Domeniconi et al., 2002, Fournier et al., 2001, Wang et al., 2002a) and is expressed in many types of neurons and their axons in the CNS (X. Wang et al., 2002). Recently, B lymphocyte stimulator (BLyS), which is a tumor necrosis factor superfamily member that is expressed in astrocytes in the CNS (Krumbholz et al., 2005), has also been identified as a functional ligand for NgR1 (Zhang et al., 2009). NgR1 forms a receptor complex with leucine-rich repeat and immunoglobulin domain-containing Nogo receptor-interacting protein 1 (LINGO-1) (Mi et al., 2004) and either the 75-kDa neurotrophin receptor (p75NTR) (Yamashita et al., 2002) or tumor necrosis factor receptor superfamily member 19 (TROY) (Park et al., 2005). These co-receptors play a role in transmitting signals to intracellular molecules such as RhoA (Mi et al., 2004, Niederöst et al., 2002, Park et al., 2005, Yamashita et al., 2002) and its effector, Rho-associated, coiled-coil containing protein kinase (ROCK) (Niederöst et al., 2002). Binding of these four glial components to NgR1 triggers signal transduction to downstream molecules via the NgR1 co-receptors to induce growth cone collapse and neurite outgrowth inhibition (Schwab, 2010, Yiu and He, 2006). This signaling pathway, which is called Nogo signaling, enormously restricts the ability of neurons to regenerate their damaged axons in the CNS (Schwab, 2010, Yiu and He, 2006).
Accumulated evidence has shown that neutralizing antibodies against Nogo (Freund et al., 2006), an NgR1 antagonist that is specific for Nogo (GrandPré et al., 2002), soluble NgR1 peptides (Li et al., 2004), and genetic deletion of Nogo (Kim et al., 2003) or NgR1 (Kim et al., 2004) promote the histological and functional regeneration of damaged CNS axons. Furthermore, triple mutation of Nogo, MAG, and OMgp exhibits greater improvement in axonal regeneration in the injured CNS compared with single mutation of Nogo (Cafferty et al., 2010). These reports suggest that inhibition of the function of multiple glial components that bind to NgR1 may more effectively improve the ability of neurons to regenerate their damaged CNS axons, although whether inhibition of BLyS function contributes to the regeneration of damaged CNS axons in vivo remains unknown.
Recently, we identified lateral olfactory tract usher substance (LOTUS)/cartilage acidic protein-1B (Crtac1B) as a novel molecule that functions in axonal bundle formation by antagonizing NgR1 function by Nogo (Sato et al., 2011). However, whether LOTUS exerts antagonistic activity on NgR1 that is bound by the other three ligands remains unknown. We show here that LOTUS suppressed axonal growth inhibition that was mediated by NgR1 function by blocking the binding of these three types of NgR1 ligands. Our findings suggest that LOTUS functions as a potent endogenous antagonist for NgR1 when bound by all the known NgR1 ligands, raising the possibility that LOTUS may overcome the failure of damaged CNS neurons to regenerate due to NgR1 function.
Section snippets
LOTUS blocks the binding of MAG, OMgp, and BLyS to NgR1
We previously showed that LOTUS overexpression together with NgR1 in COS7 cells blocks the binding of Nogo66, which is the functional domain of NogoA involved in axon growth inhibition (GrandPré et al., 2000), to NgR1 (Sato et al., 2011). To examine whether LOTUS blocks the binding of the other three NgR1 ligands to NgR1, we performed a binding assay with alkaline phosphatase (AP)-fused MAG (MAG-AP), OMgp (AP-OMgp), or BLyS (AP-BLyS) to NgR1, which were overexpressed together with LOTUS in COS7
Discussion
The function of Nogo, MAG, OMgp, and BLyS through their binding to NgR1 powerfully prevents neuronal regeneration after injury to the adult CNS (Schwab, 2010, Yiu and He, 2006). This prevention is partially attenuated by inhibition of Nogo function (Freund et al., 2006, GrandPré et al., 2002, Kim et al., 2003). Moreover, this attenuation is more effectively enhanced by inhibition of the function of multiple NgR1 ligands (Cafferty et al., 2010). Recently, we found that LOTUS blocks Nogo66
Animals
Fertilized White Leghorn eggs were purchased from Yamagishi Co. and incubated at 37 °C in a standard egg incubator. The lotus mutant mice were generated as previously described (Sato et al., 2011) and were housed in a standard mouse facility with free access to autoclaved food and water. Genotypes of the offspring of the mutant mice were assessed using polymerase chain reaction (PCR).
Throughout the experimental procedures, all efforts were made to minimize the number of animals used and their
Acknowledgments
This work was supported by a grant-in-aid from the Ministry of Education, Culture, Sports, Science and Technology of Japan (to K.T. and Y.G.) and by grants for Research and Development Project of Yokohama City University (to K.T. and Y.G.). We thank Dr. Stephen M. Strittmatter at Yale University for AP-OMgp plasmid. The authors are grateful to Drs. Fumio Nakamura, Yukio Sasaki, and Naoya Yamashita at Yokohama City University for helpful discussions and Mitsuba Matsuura for technical assistance.
References (34)
- et al.
Myelin-associated glycoprotein interacts with the Nogo66 receptor to inhibit neurite outgrowth
Neuron
(2002) - et al.
LINGO-1 antagonist promotes functional recovery and axonal sprouting after spinal cord injury
Mol. Cell. Neurosci.
(2006) - et al.
Axon regeneration in young adult mice lacking Nogo-A/B
Neuron
(2003) - et al.
Nogo-66 receptor prevents raphespinal and rubrospinal axon regeneration and limits functional recovery from spinal cord injury
Neuron
(2004) - et al.
The carboxyl-terminal region of Crtac1B/LOTUS acts as a functional domain in endogenous antagonism to Nogo receptor-1
Biochem. Biophys. Res. Commun.
(2012) - et al.
Identification of myelin-associated glycoprotein as a major myelin-derived inhibitor of neurite growth
Neuron
(1994) - et al.
A TNF receptor family member, TROY, is a coreceptor with Nogo receptor in mediating the inhibitory activity of myelin inhibitors
Neuron
(2005) - et al.
PirB is a functional receptor for myelin inhibitors of axonal regeneration
Science
(2008) - et al.
Structure and axon outgrowth inhibitor binding of the Nogo-66 receptor and related proteins
EMBO J.
(2003) - et al.
MAG and OMgp synergize with Nogo-A to restrict axonal growth and neurological recovery after spinal cord trauma
J. Neurosci.
(2010)
Rho signaling pathway targeted to promote spinal cord repair
J. Neurosci.
Identification of a receptor mediating Nogo-66 inhibition of axonal regeneration
Nature
Truncated soluble Nogo receptor binds Nogo-66 and blocks inhibition of axon growth by myelin
J. Neurosci.
Rho kinase inhibition enhances axonal regeneration in the injured CNS
J. Neurosci.
Nogo-A-specific antibody treatment enhances sprouting and functional recovery after cervical lesion in adult primates
Nat. Med.
Identification of the Nogo inhibitor of axon regeneration as a Reticulon protein
Nature
Nogo-66 receptor antagonist peptide promotes axonal regeneration
Nature
Cited by (29)
LOTUS overexpression via ex vivo gene transduction further promotes recovery of motor function following human iPSC-NS/PC transplantation for contusive spinal cord injury
2021, Stem Cell ReportsCitation Excerpt :On the other hand, in this experiment, we were unable to easily provide evidence that inhibition of NgR1 signaling by LOTUS expression in hiPSC-NS/PCs directly induced improved functional recovery after SCI. However, in vitro, Takei and coworkers showed that LOTUS binds to NgR1 and blocks NgR1 ligand binding to its receptor (Kurihara et al., 2012, 2014). Therefore, LOTUS suppresses NgR1-induced inhibition of axonal elongation and growth cone collapse (Kurihara et al., 2014).
Axonal regeneration and functional recovery driven by endogenous Nogo receptor antagonist LOTUS in a rat model of unilateral pyramidotomy
2020, Experimental NeurologyCitation Excerpt :Recently, cartilage acidic protein-1B (Crtac1B), also known as lateral olfactory tract usher substance (LOTUS), has been reported as an endogenous Nogo receptor inhibitor (Kurihara et al., 2012; Sato et al., 2011). In vitro, LOTUS has been shown to almost completely antagonize Nogo, MAG, OMgp, chondroitin sulfate proteoglycan, and BlyS as well as NgR1 signaling-mediated axonal growth inhibition (Kawakami et al., 2018a; Kawakami et al., 2018b; Kurihara et al., 2014; Kurihara et al., 2017). In a mouse model of spinal cord injury (SCI), LOTUS expression level correlated with functional recovery, and overexpression of LOTUS enhanced the regeneration in some tracts (Hirokawa et al., 2017; Ito et al., 2018).
The soluble form of LOTUS inhibits Nogo receptor type 1-mediated signaling induced by B lymphocyte stimulator and chondroitin sulfate proteoglycans
2018, Neuroscience LettersCitation Excerpt :We identified LOTUS as an endogenous NgR1 antagonist that exists as a membrane-bound form and a secreted (soluble) form [16,19]. The membrane-bound form of LOTUS binds directly with NgR1 and blocks the binding of these ligands to NgR1, thereby inhibiting NgR1-mediated signaling completely [12,13,16]. On the other hand, we have recently reported that the soluble form of LOTUS (s-LOTUS) suppressed NgR1-mediated signaling induced by myelin-associated inhibitors (MAIs: Nogo, MAG and OMgp), by inhibiting NgR1-p75NTR interaction, and not by competing with these ligands for binding to NgR1 [10].
Blockade of chondroitin sulfate proteoglycans-induced axonal growth inhibition by LOTUS
2017, NeuroscienceCitation Excerpt :We previously identified lateral olfactory tract usher substance (LOTUS) as a novel key molecule for axonal bundling of lateral olfactory tract by interacting with NgR1 and abolishing Nogo-induced axon growth inhibition (Sato et al., 2011). Recently, we found that LOTUS suppresses MAG, OMgp, and BLyS-induced axon growth inhibition (Kurihara et al., 2014). However, it is unknown whether LOTUS also has this suppressive action on CSPG-induced axon growth inhibition.
Decreased plasma cartilage acidic protein 1 in COVID-19
2023, Physiological Reports