Liao HY

References (4)

Title : Lysophosphatidic Acid Signalling Regulates Human Sperm Viability via the Phosphoinositide 3-Kinase\/AKT Pathway - Liao_2023_Cells_12_
Author(s) : Liao HY , O'Flaherty C
Ref : Cells , 12 : , 2023
Abstract : Lysophosphatidic acid (LPA) signalling is essential for maintaining germ cell viability during mouse spermatogenesis; however, its role in human spermatozoa is unknown. We previously demonstrated that peroxiredoxin 6 (PRDX6) calcium-independent phospholipase A(2) (iPLA(2)) releases lysophospholipids such as LPA or arachidonic acid (AA) and that inhibiting PRDX6 iPLA(2) activity impairs sperm cell viability. The exogenous addition of LPA bypassed the inhibition of PRDX6 iPLA(2) activity and maintained the active phosphoinositide 3-kinase (PI3K)/AKT pathway. Here, we aimed to study PI3K/AKT pathway regulation via LPA signalling and protein kinases in maintaining sperm viability. The localization of LPARs in human spermatozoa was determined using immunocytochemistry, and P-PI3K and P-AKT substrate phosphorylations via immunoblotting. Sperm viability was determined using the hypo-osmotic swelling test. LPAR1, 3, 5 and 6 were located on the sperm plasma membrane. The inhibition of LPAR1-3 with Ki16425 promoted the impairment of sperm viability and decreased the phosphorylation of PI3K AKT substrates. Inhibitors of PKC, receptor-type PTK and PLC impaired sperm viability and the PI3K/AKT pathway. Adding 1-oleoyl-2-acetyl-snglycerol (OAG), a cell-permeable analog of diacylglycerol (DAG), prevented the loss of sperm viability and maintained the phosphorylation of PI3K. In conclusion, human sperm viability is supported by LPAR signalling and regulated by PLC, PKC and RT-PTK by maintaining phosphorylation levels of PI3K and AKT substrates.
ESTHER : Liao_2023_Cells_12_
PubMedSearch : Liao_2023_Cells_12_
PubMedID: 37681929

Title : Loss-of-function variation in the DPP6 gene is associated with autosomal dominant microcephaly and mental retardation - Liao_2013_Eur.J.Med.Genet_56_484
Author(s) : Liao C , Fu F , Li R , Yang WQ , Liao HY , Yan JR , Li J , Li SY , Yang X , Li DZ
Ref : Eur Journal of Medical Genetics , 56 :484 , 2013
Abstract : The molecular basis of autosomal dominant microcephaly, a disorder associated with small head circumferences that results in variable mental retardation, is largely unknown. In the present study, we conducted a variation analysis of the DPP6 gene in patients with autosomal dominant microcephaly and variable mental retardation. The copy number variation analysis of DPP6 was performed on DNA samples from 22 patients with microcephaly using high-resolution, array-based genomic hybridization, and sequence analysis was performed to screen mutations in another 50 microcephalic patients. Two de novo deletions and one missense mutation in familial microcephalic patients were identified. The transfection of plasmids encoding green fluorescent protein-pLLU2G-shDPP6 fusion proteins in mouse brains revealed that the decreased expression of the DPP6 gene slightly reduced the weight of the mouse brains and resulted in mouse learning disabilities compared with their wild-type littermates. Our data indicate that the loss-of-function variations in DPP6 are associated with autosomal dominant microcephaly and mental retardation. DPP6 appears to play a major role in the regulation of proliferation and migration of neurons in neurogenesis, most likely by participating in neuronal electrical excitability, synaptic integration, and plasticity.
ESTHER : Liao_2013_Eur.J.Med.Genet_56_484
PubMedSearch : Liao_2013_Eur.J.Med.Genet_56_484
PubMedID: 23832105
Gene_locus related to this paper: human-DPP6

Title : Alterations of the acetylcholinesterase enzyme in the oriental fruit fly Bactrocera dorsalis are correlated with resistance to the organophosphate insecticide fenitrothion - Hsu_2008_Insect.Biochem.Mol.Biol_38_146
Author(s) : Hsu JC , Wu WJ , Haymer DS , Liao HY , Feng HT
Ref : Insect Biochemistry & Molecular Biology , 38 :146 , 2008
Abstract : Alterations of the structure and activity of the enzyme acetylcholinesterase (AChE) leading to resistance to organophosphate insecticides have been examined in the oriental fruit fly, Bactrocera dorsalis (Hendel), an economic pest of great economic importance in the Asia-Pacific region. We used affinity chromatography to purify AChE isoenzymes from heads of insects from lines showing the phenotypes of resistance and sensitivity to insecticide treatments. The AChE enzyme from a strain selected for resistance to the insecticide fenitrothion shows substantially lower catalytic efficiency for various substrates and 124-, 373- and 5810-fold less sensitivity to inhibition by paraoxon, eserine and fenitroxon, respectively, compared to that of the fenitrothion susceptible line. Using peptide mass fingerprinting, we also show how specific changes in the structure of the AChE enzymes in these lines relate to the resistant and sensitive alleles of the AChE (ace) gene characterized previously in this species (described in Hsu, J.-C., Haymer, D.S., Wu, W.-J., Feng, H.-T., 2006. Mutations in the acetylcholinesterase gene of Bactrocera dorsalis associated with resistance to organophosphorus insecticides. Insect Biochem. Mol. Biol. 36, 396-402). Polyclonal antibodies specific to the purified isoenzymes and real-time PCR were also used to show that both the amount of the isoenzyme present and the expression levels of the ace genes were not significantly different between the R and S lines, indicating that quantitative changes in gene expression were not significantly contributing to the resistance phenotype. Overall, our results support a direct causal relationship between the mutations previously identified in the ace gene of this species and qualitative alterations of the structure and function of the AChE enzyme as the basis for the resistance phenotype. Our results also provide a basis for further comparisons of insecticide resistance phenomena seen in closely related species, such as Bactrocera oleae, as well as in a wide range of more distantly related insect species.
ESTHER : Hsu_2008_Insect.Biochem.Mol.Biol_38_146
PubMedSearch : Hsu_2008_Insect.Biochem.Mol.Biol_38_146
PubMedID: 18207076

Title : Purification and characterization of acetylcholinesterase from oriental fruit fly [Bactrocera dorsalis (Hendel)] (Diptera: Tephritidae) - Hsiao_2004_J.Agric.Food.Chem_52_5340
Author(s) : Hsiao YM , Lai JY , Liao HY , Feng HT
Ref : Journal of Agricultural and Food Chemistry , 52 :5340 , 2004
Abstract : An acetylcholinesterase (AChE, EC was purified from the head of the insecticide susceptible oriental fruit fly, Bactrocera dorsalis (Hendel), by affinity chromatography of Triton X-100 extract. The degree of purification was about 8183-fold with recoveries of 52%. The molecular mass of purified AChE was 116 kDa for its native protein (nonreduced form) and 61 kDa for its subunits (reduced form) as revealed on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), suggesting that the homodimer of AChE linked with disulfide bonds. Nondenaturing PAGE of the purified AChE revealed only one molecular form. The maximum velocities (V(max)) for hydrolyzing acetylthiocholine (ATC), propionylthiocholine, and S-butyrylthiocholine were 833.3, 222.2, and 57.5 micromol/min/mg, and the Michaelis constants (K(m)) were 87.9, 26.9, and 195.3 microM, respectively. More than 97% of AChE activity was inhibited by 10 microM eserine or BW284C51, but only 53% of the activity was inhibited by ethopropazine at the same concentration. On the basis of the substrate and inhibitor specificities, the purified enzyme appeared to be a true AChE. Nevertheless, the purified AChE exhibited some distinctive characteristics including (i) a lack of the substrate inhibition phenomenon when using ATC as the hydrolyzing substrate and (ii) a higher V(m) value for ATC than AChE from other insect species. These biochemical properties may show that AChE purified from the oriental fruit fly may have structural differences from those of other insect species.
ESTHER : Hsiao_2004_J.Agric.Food.Chem_52_5340
PubMedSearch : Hsiao_2004_J.Agric.Food.Chem_52_5340
PubMedID: 15315367