Retinal ganglion cells (RGCs) of mammals lose the ability to regenerate injured axons during postnatal maturation, but little is known about the underlying molecular mechanisms.
Objective:
It remains of particular importance to understand the mechanisms of axonal regeneration to develop new therapeutic approaches for nerve injuries.
Methods:
Retinas from newborn to adult monkeys (Callithrix jacchus)
1
were obtained immediately after death and cultured in vitro. Growths of axons were monitored using microscopy and time-lapse video cinematography. Immunohistochemistry, Western blotting, qRT-PCR, and genomics were performed to characterize molecules associated with axonal regeneration and growth. A genomic screen was performed by using retinal explants versus native and non-regenerative explants obtained from eye cadavers on the day of birth, and hybridizing the mRNA with cross-reacting cDNA on conventional human microarrays. Followed the genomic screen, siRNA experiments were conducted to identify the functional involvement of identified candidates.
Results:
Neuron-specific human ribonucleoprotein N (snRPN) was found to be a potential regulator of impaired axonal regeneration during neuronal maturation in these animals. In particular, up-regulation of snRPN was observed during retinal maturation, coinciding with a decline in regenerative ability. Axon regeneration was reactivated in snRPN-knockout retinal ex vivo explants of adult monkey.
Conclusion:
These results suggest that coordinated snRPN-driven activities within the neuron-specific ribonucleoprotein complex regulate the regenerative ability of RGCs in primates, thereby highlighting a potential new role for snRPN within neurons and the possibility of novel postinjury therapies.
BarlowD.P. (2011). Genomic imprinting: A mammalian epigenetic discovery model. Annual Review of Genetics, 45, 379–403.
2.
BattleD.J., KasimM., YongJ., LottiF., LauC.K., MouaikelJ., … DreyfussG. (2006). The SMN complex: An assembly machine for RNPs. Cold Spring Harbor Symposia on Quantitative Biology, 71, 313–320.
3.
BenowitzL.I., HeZ., & GoldbergJ.L. (2017). Reaching the brain: Advances in optic nerve regeneration. Experimental Neurology, 287(Pt 3), 365–373.
4.
BohmM.R., PfrommerS., ChiwittC., BrucknerM., MelkonyanH., & ThanosS. (2012). Crystallin-beta-b2-overexpressing NPCs support the survival of injured retinal ganglion cells and photoreceptors in rats. Investigative Ophthalmology & Visual Science, 53(13), 8265–8279.
5.
CaiD., QiuJ., CaoZ., McAteeM., BregmanB.S., & FilbinM.T. (2001). Neuronal cyclic AMP controls the developmental loss in ability of axons to regenerate. Journal of Neuroscience, 21(13), 4731–4739.
6.
CattanachB.M., BarrJ.A., EvansE.P., BurtenshawM., BeecheyC.V., LeffS.E., … JonesJ. (1992). A candidate mouse model for Prader-Willi syndrome which shows an absence of Snrpn expression. Nature Genetics, 2(4), 270–274.
7.
CavailleJ. (2017). Box C/D small nucleolar RNA genes and the Prader-Willi syndrome: A complex interplay, Wiley Interdisciplinary Reviews: RNA.
8.
ChariA., GolasM.M., KlingenhagerM., NeuenkirchenN., SanderB., EnglbrechtC., … FischerU. (2008). An assembly chaperone collaborates with the SMN complex to generate spliceosomal SnRNPs. Cell, 135(3), 497–509.
9.
CharrouxB., PellizzoniL., PerkinsonR.A., YongJ., ShevchenkoA., MannM., & DreyfussG. (2000). Gemin4. A novel component of the SMN complex that is found in both gems and nucleoli. The Journal of Cell Biology, 148(6), 1177–1186.
10.
ChenD.F., JhaveriS., & SchneiderG.E. (1995). Intrinsic changes in developing retinal neurons result in regenerative failure of their axons. Proceedings of the National Academy of Sciences USA, 92(16), 7287–7291.
11.
ChenD.F., SchneiderG.E., MartinouJ.C., & TonegawaS. (1997). Bcl-2 promotes regeneration of severed axons in mammalian CNS. Nature, 385(6615), 434–439.
12.
CheonC.K. (2016). Genetics of Prader-Willi syndrome and Prader-Will-Like syndrome. Annals of Pediatric Endocrinology & Metabolism, 21(3), 126–135.
13.
ChoK.S., YangL., LuB., Feng MaH., HuangX., PeknyM., & ChenD.F. (2005). Re-establishing the regenerative potential of central nervous system axons in postnatal mice. Journal of Cell Science, 118(Pt 5), 863–872.
14.
Doron-MandelE., FainzilberM., & TerenzioM. (2015). Growth control mechanisms in neuronal regeneration. FEBS Letters, 589(14), 1669–1677.
15.
FalliniC., RouanetJ.P., Donlin-AspP.G., GuoP., ZhangH., SingerR.H., … BassellG.J. (2014). Dynamics of survival of motor neuron (SMN) protein interaction with the mRNA-binding protein IMP facilitates its trafficking into motor neuron axons. Developmental Neurobiology, 74(3), 319–332.
16.
Ferguson-SmithM.A. (2011). Putting medical genetics into practice. Annual Review of Genomics and Human Genetics, 12, 1–23.
17.
GallagherR.C., PilsB., AlbalwiM., & FranckeU. (2002). Evidence for the role of PWCR1/HBII-85 C/D box small nucleolar RNAs in Prader-Willi syndrome. American Journal of Human Genetics, 71(3), 669–678.
18.
GaoY., DengK., HouJ., BrysonJ.B., BarcoA., NikulinaE., … FilbinM.T. (2004). Activated CREB is sufficient to overcome inhibitors in myelin and promote spinal axon regeneration in vivo. Neuron, 44(4), 609–621.
19.
GenainC.P., & HauserS.L. (2001). Experimental allergic encephalomyelitis in the New World monkey Callithrix jacchus. Immunological Reviews, 183, 159–172.
20.
GlazkoG.V., & NeiM. (2003). Estimation of divergence times for major lineages of primate species. Molecular Biology and Evolution, 20(3), 424–434.
21.
GoldbergJ.L., KlassenM.P., HuaY., & BarresB.A. (2002). Amacrine-signaled loss of intrinsic axon growth ability by retinal ganglion cells. Science, 296(5574), 1860–1864.
22.
GouletA., MajorJ., JunY., GrossS.P., RosenfeldS.S., & MooresC.A. (2014). Comprehensive structural model of the mechanochemical cycle of a mitotic motor highlights molecular adaptations in the kinesin family. Proceedings of the National Academy of Sciences USA, 111(5), 1837–1842.
23.
GreenfieldJ.J., & HighS. (1999). The Sec61 complex is located in both the ER and the ER-Golgi intermediate compartment. Journal of Cell Science, 112(Pt 10), 1477–1486.
24.
HergethS.P., & SchneiderR. (2015). The H1 linker histones: Multifunctional proteins beyond the nucleosomal core particle. EMBO Reports, 16(11), 1439–1453.
25.
HohjohH., AkariH., FujiwaraY., TamuraY., HiraiH., & WadaK. (2009). Molecular cloning and characterization of the common marmoset huntingtin gene. Gene, 432(1-2), 60–66.
26.
JanasM.M., KhaledM., SchubertS., BernsteinJ.G., GolanD., VeguillaR.A., … NovinaC.D. (2011). Feed-forward microprocessing and splicing activities at a microRNA-containing intron. PLoS Genetics, 7(10), e1002330.
27.
KimY., LeeH.M., XiongY., SciakyN., HulbertS.W., CaoX., … JiangY.H. (2017). Targeting the histone methyltransferase G9a activates imprinted genes and improves survival of a mouse model of Prader-Willi syndrome. Nature Medicine, 23(2), 213–222.
28.
KishoreS., & StammS. (2006). Regulation of alternative splicing by snoRNAs. Cold Spring Harbor Symposia on Quantitative Biology, 71, 329–334.
LiuJ., GaoH.Y., & WangX.F. (2015). The role of the Rho/ROCK signaling pathway in inhibiting axonal regeneration in the central nervous system. Neural Regeneration Research, 10(11), 1892–1896.
32.
ManzardoA.M., & ButlerM.G. (2016). Examination of Global Methylation and Targeted Imprinted Genes in Prader-Willi Syndrome. Journal of Clinical Epigenetics, 2(3).
33.
MeguroM., MitsuyaK., NomuraN., KohdaM., KashiwagiA., NishigakiR., … OshimuraM. (2001). Large-scale evaluation of imprinting status in the Prader-Willi syndrome region: An imprinted direct repeat cluster resembling small nucleolar RNA genes. Human Molecular Genetics, 10(4), 383–394.
34.
Mertsch S. ThanosS. (2014). Opposing signaling of ROCK1 and ROCK2 determines the switching of substrate specificity and the mode of migration of glioblastoma cells. Molecular Neurobiology, 49(2), 900–915.
35.
MladinicM., WintzerM., Del BelE., CasselerC., LazarevicD., CrovellaS., … NichollsJ. (2005). Differential expression of genes at stages when regeneration can and cannot occur after injury to immature mammalian spinal cord. Cellular and Molecular Neurobiology, 25(2), 407–426.
36.
MooreD.L., BlackmoreM.G., HuY., KaestnerK.H., BixbyJ.L., LemmonV.P., & GoldbergJ.L. (2009). KLF family members regulate intrinsic axon regeneration ability. Science, 326(5950), 298–301.
37.
NeuenkirchenN., EnglbrechtC., OhmerJ., ZiegenhalsT., ChariA., & FischerU. (2015). Reconstitution of the human U snRNP assembly machinery reveals stepwise Sm protein organization. The EMBO Journal, 34(14), 1925–1941.
38.
NichollsJ., & SaundersN. (1996). Regeneration of immature mammalian spinal cord after injury. Trends in Neurosciences, 19(6), 229–234.
NilsenT.W. (2003). The spliceosome: The most complex macromolecular machine in the cell?BioEssays, 25(12), 1147–1149.
41.
ParkK.K., LiuK., HuY., SmithP.D., WangC., CaiB., … HeZ. (2008). Promoting axon regeneration in the adult CNS by modulation of the PTEN/mTOR pathway. Science, 322(5903), 963–966.
42.
PaulerF.M., BarlowD.P., & HudsonQ.J. (2012). Mechanisms of long range silencing by imprinted macro non-coding RNAs. Current Opinion in Genetics & Development, 22(3), 283–289.
43.
PaushkinS., GubitzA.K., MassenetS., & DreyfussG. (2002). The SMN complex, an asemsblyosome of ribonucleoproteins. Current Opinion in Cell Biology, 14(3), 305–312.
44.
PlaggeA. (2012). Non-coding RNAs at the gnas and snrpn-ube3a imprinted gene loci and their involvement in hereditary disorders. Frontiers in Genetics, 3, 264.
45.
PrescottA.R., BalesA., JamesJ., Trinkle-MulcahyL., & SleemanJ.E. (2014). Time-resolved quantitative proteomics implicates the core snRNP protein SmB together with SMN in neural trafficking. Journal of Cell Science, 127(Pt 4), 812–827.
46.
RoseK., SchroerU., VolkG.F., SchlattS., KonigS., FeigenspanA., & ThanosS. (2008). Axonal regeneration in the organotypically cultured monkey retina: Biological aspects, dependence on substrates and age-related proteomic profiling. Restorative Neurology and Neuroscience, 26(4-5), 249–266.
47.
RunteM., VaronR., HornD., HorsthemkeB., & BuitingK. (2005). Exclusion of the C/D box snoRNA gene cluster HBII-52 from a major role in Prader-Willi syndrome. Human Genetics, 116(3), 228–230.
48.
SchuleB., AlbalwiM., NorthropE., FrancisD.I., RowellM., SlaterH.R., … FranckeU. (2005). Molecular breakpoint cloning and gene expression studies of a novel translocation t(4;15)(q27;q11.2) associated with Prader-Willi syndrome. BMC Medical Genetics, 6, 18.
49.
SchwabM.E. (1990). Myelin-associated inhibitors of neurite growth and regeneration in the CNS. Trends in Neurosciences, 13(11), 452–456.
50.
SkryabinB.V., GubarL.V., SeegerB., PfeifferJ., HandelS., RobeckT., … BrosiusJ. (2007). Deletion of the MBII-85 snoRNA gene cluster in mice results in postnatal growth retardation. PLoS Genetics, 3(12), e235.
51.
StefanM., PortisT., LongneckerR., & NichollsR.D. (2005). A nonimprinted Prader-Willi Syndrome (PWS)-region gene regulates a different chromosomal domain in trans but the imprinted pws loci do not alter genome-wide mRNA levels. Genomics, 85(5), 630–640.
52.
TatsumotoS., AdatiN., TohtokiY., SakakiY., BoroviakT., HabuS., … SatakeM. (2013). Development and characterization of cDNA resources for the common marmoset: One of the experimental primate models. DNA Research, 20(3), 255–262.
53.
WillC.L., & LuhrmannR. (2001). Spliceosomal UsnRNP biogenesis, structure and function. Current Opinion in Cell Biology, 13(3), 290–301.
54.
YangT., AdamsonT.E., ResnickJ.L., LeffS., WevrickR., FranckeU., … BrannanC.I. (1998). A mouse model for Prader-Willi syndrome imprinting-centre mutations. Nature Genetics, 19(1), 25–31.
55.
ZhengJ., SunJ., LuX., ZhaoP., LiK., & LiL. (2016). BDNF promotes the axonal regrowth after sciatic nerve crush through intrinsic neuronal capability upregulation and distal portion protection. Neuroscience Letters, 621, 1–8.
