Trehalase Regulates Neuroepithelial Stem Cell Maintenance and Differentiation in the Drosophila Optic Lobe

Abstract

As one of the major hydrolases in Drosophila, trehalase (Treh) catalyzes the hydrolysis of trehalose into glucose providing energy for flight muscle activity. Treh is highly conserved from bacteria to humans, but little is known about its function during animal development. Here, we analyze the function of Treh in Drosophila optic lobe development. In the optic lobe, neuroepithelial cells (NEs) first divide symmetrically to expand the stem cell pool and then differentiate into neuroblasts, which divide asymmetrically to generate medulla neurons. We find that the knockdown of Treh leads to a loss of the lamina and a smaller medulla. Analyses of Treh RNAi-expressing clones and loss-of-function mutants indicate that the lamina and medulla phenotypes result from neuroepithelial disintegration and premature differentiation into medulla neuroblasts. Although the principal role of Treh is to generate glucose, the Treh loss-of-function phenotype cannot be rescued by exogenous glucose. Thus, our results indicate that in addition to being a hydrolase, Treh plays a role in neuroepithelial stem cell maintenance and differentiation during Drosophila optic lobe development.

Adaptation to dietary conditions by trehalose metabolism in Drosophila

“…These results are consistent with our previous report 9 . Because both Treh 18 and Treh 41 have a deletion/insertion within the intron region of the Treh gene, the hypomorphic phenotype of Treh 18 and Treh 41 is likely due to the reduced transcription and/or alterations of Treh mRNA, as reported 17 . Consistent with the pupal lethal phenotype, Treh 18 significantly reduced the expression of c Treh in addition to the reduction in sTreh (Fig.…”

“…IPC neuroepithelial cells are located in the inner and proximal side of the optic lobe and give rise to IPC neuroblasts, which are located on the distal side 19, 20 . It has been reported that Treh mutants exhibit disorganization of the optic lobe neuroepithelia in the central nervous system 17 . This phenotype is likely independent of its catalytic activity, because the increase in dietary glucose levels fails to rescue the mutant phenotype 17 .

Figure 1 Treh mutants do not cause disorganization of the optic lobe in the central nervous system.

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“…It has been reported that Treh mutants exhibit disorganization of the optic lobe neuroepithelia in the central nervous system 17 . This phenotype is likely independent of its catalytic activity, because the increase in dietary glucose levels fails to rescue the mutant phenotype 17 .

Figure 1 Treh mutants do not cause disorganization of the optic lobe in the central nervous system. ( A ) Schematic diagram of the frontal view of the larval optic lobe.

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Is trehalose an autophagic inducer? Unraveling the roles of non-reducing disaccharides on autophagic flux and alpha-synuclein aggregation

“… 25 In terms of human samples, in the skin fibroblasts from healthy subjects and HD patients, trehalose reversed the effects of proteasome inhibitor epoxomicin and inhibited accumulation of huntingtin proteins in cells. 47 …”

Functional characterization of three trehalase genes regulating the chitin metabolism pathway in rice brown planthopper using RNA interference

“…These phenotypes resulted from the silencing of genes involved in the chitin biosynthesis pathway or chitin degradation-related genes, including CHS 30 33 38 66 , Cht 36 , chitin deacetylase gene 34 40 , and β-N-acetylhexosaminidase gene 41 . Except for defaults in chitin metabolism, TRE silencing in Drosophila leads to loss of the lamina and reduction of the medulla 67 .…”