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Wai-Sum O ( 柯慧心 )
Department of Anatomy
Anatomy Office: (852) 2819-9238 (voice)
Reproductive Biologist specialized in oocyte and embryonic development
Using a golden hamster model, we found the antioxidative enzymes in the male accessory sex gland secretions afford protection to the integrity of sperm genome. Moreover, we are the first group to demonstrate that the ASG secretions exert epigenetic modifications in the embryonic genome. Applying various morphological and molecular techniques, we studied demethylation in sperm after fertilization and methylation patterns in the subsequent development of these embryos.
In our laboratory, we have established a follicle culture system to mature oocytes in vitro. The current trend of culturing follicles/oocytes opens up new pathways to infertile patients. We are currently studying cytoplasmic maturity of oocytes especially on mitochondria accumulation during maturation using ATP assays, RT-PCR, confocal microscopy as well as nanotechnology techniques.
Currently my laboratory is interested in the study of adrenomedullin male and female reproduction. Adrenomedullin is a novel vasorelaxant peptide and has been found by our group to play a paracrine role in the regulation of testicular hormone function. We are studying the role of this hormone in the male accessory sex glands. In the female, adrenomedullin hormone also has an important role in folliculogenesis, luteogenesis, implantation and maintenance of pregnancy.
1. Liao SB, Cheung KH, Cheung MP, To YT, O WS, Tang F. Adrenomedullin Increased the Short-Circuit Current in the Pig Oviduct Through Chloride Channels via the CGRP Receptor: Mediation by cAMP and Calcium Ions But Not by Nitric Oxide. Biol Reprod. 2013 Oct 24;89(4):99. doi: 10.1095/biolreprod.113.109934. Print 2013.
2. Sy SM, Jiang J, O WS, Deng Y, Huen MS.The ubiquitin specific protease USP34 promotes ubiquitin signaling at DNA double-strand breaks.Nucleic Acids Res. 2013 Oct 1;41(18):8572-80. doi: 10.1093/nar/gkt622. Epub 2013 Jul 17.
3. O WS. The nasal epithelium provides an easier alternative than the oviduct for the study of ciliary beating. Fertil Steril. 2013 Aug;100(2):e4. doi: 10.1016/j.fertnstert.2013.05.006. Epub 2013 Jun 4. No abstract available.
4. Li L, Ma P, Liu Y, Huang C, O WS, Tang F, Zhang JV.Intermedin attenuates LPS-induced inflammation in the rat testis. PLoS One. 2013 Jun 4;8(6):e65278. doi: 10.1371/journal.pone.0065278. Print 2013.
5. O WS, Li HW, Liao SB, Cheung AN, Ng EH, Yeung WS, Ho JC, Tang F. Decreases in adrenomedullin expression and ciliary beat frequency in the nasal epithelium in tubal pregnancy. Fertil Steril. 2013 Aug;100(2):459-63.e1. doi: 10.1016/j.fertnstert.2013.04.007. Epub 2013 May 10.
6. Wong CW, O WS, Tang F. Intermedin in rat uterus: changes in gene expression and peptide levels across the estrous cycle and its effects on uterine contraction. Reprod Biol Endocrinol. 2013 Feb 25;11:13. doi: 10.1186/1477-7827-11-13.
7. Chen H, Liao SB, Cheung MP, Chow PH, Cheung AL, O WS. Effects of sperm DNA damage on the levels of RAD51 and p53 proteins in zygotes and 2-cell embryos sired by golden hamsters without the major accessory sex glands. Free Radic Biol Med. 2012 Aug 15;53(4):885-92. doi: 10.1016/j.freeradbiomed.2012.06.007. Epub 2012 Jun 15.
8. Liao SB, O WS, Tang F. Adrenomedullin inhibits norepinephrine-induced contraction of rat seminal vesicle. Urology. 2012 Jul;80(1):224.e1-5. doi: 10.1016/j.urology.2012.03.036. Epub 2012 May 23.
9. Liao SB, Li HW, Ho JC, Yeung WS, Ng EH, Cheung AN, Tang F, O WS. Possible role of adrenomedullin in the pathogenesis of tubal ectopic pregnancy. J Clin Endocrinol Metab. 2012 Jun;97(6):2105-12. doi: 10.1210/jc.2011-3290. Epub 2012 Mar 28
10. Li L, Tang F, O WS. Preimplantation antagonism of adrenomedullin action compromises fetoplacental development and reduces litter size. Theriogenology. 2012 Jun;77(9):1846-53. doi: 10.1016/j.theriogenology.2011.12.030. Epub 2012 Feb 25.
11. Wang MJ, Ou JX, Chen GW, Wu JP, Shi HJ, O WS, Martin-DeLeon PA, Chen H. Does prohibitin expression regulate sperm mitochondrial membrane potential, sperm motility, and male fertility? Antioxid Redox Signal. 2012 Aug 1;17(3):513-9. doi: 10.1089/ars.2012.4514. Epub 2012 Mar 20.
12. Wong PF, O WS, Tang F. An ontogenic study of adrenomedullin gene expression in the rat lung, adrenal, kidney, and heart. Endocrine. 2012 Apr;41(2):256-65. doi: 10.1007/s12020-011-9552-4. Epub 2011 Nov 1.
13. Li L, O WS, Tang F. Adrenomedullin in rat follicles and corpora lutea: expression, functions and interaction with endothelin-1. Reprod Biol Endocrinol. 2011 Aug 9;9:111. doi: 10.1186/1477-7827-9-111.
14. Liao SB, Ho JC, Tang F, O WS. Adrenomedullin increases ciliary beat frequency and decreases muscular contraction in the rat oviduct. Reproduction. 2011 Mar;141(3):367-72. doi: 10.1530/REP-10-0230. Epub 2010 Dec 20.
15. Li L, Tang F, O WS. Coexpression of adrenomedullin and its receptor component proteins in the reproductive system of the rat during gestation. Reprod Biol Endocrinol. 2010 Oct 29;8:130. doi: 10.1186/1477-7827-8-130.
16. Li HW, Liao SB, Chiu PC, Tam WW, Ho JC, Ng EH, Ho PC, Yeung WS, Tang F, O WS. Expression of adrenomedullin in human oviduct, its regulation by the hormonal cycle and contact with spermatozoa, and its effect on ciliary beat frequency of the oviductal epithelium. J Clin Endocrinol Metab. 2010 Sep;95(9):E18-25. doi: 10.1210/jc.2010-0273. Epub 2010 Jun 9.
17. Chiu PC, Liao S, Lam KK, Tang F, Ho JC, Ho PC, O WS, Yao YQ, Yeung WS. Adrenomedullin regulates sperm motility and oviductal ciliary beat via cyclic adenosine 5'-monophosphate/protein kinase A and nitric oxide. Endocrinology. 2010 Jul;151(7):3336-47. doi: 10.1210/en.2010-0077. Epub 2010 May 5.
18. Zeng H.T., Yeung W.S.B., Cheung M.P.L., Ho P.C., Lee C.K.F, Zhuang G.L., Liang X.Y., O W.S. (2009) In vitro matured rat oocytes have low mitochondrial DNA, adenosine triphosphate contents and abnormal mitochondrial redistribution. Fertility and Sterility 91, 900-907.
20. Li RHW, Chiu PCN, Cheung MPL, Yeung WSB, O WS (2009) Effect of leptin on sperm motility, capacitation and acrosome reaction. International Journal of Andrology 32, 687-694.
21. Poon HK, Lee KH, Wong CL, O WS, Chow PH (2009) A lack of sperm with accessory sex gland secretuions deregulates DNA methylation and imprinted gene expression in rodent embryos. Systems Biology in Reproductive Medicine 55, 200-213.
22. Wong C.L., Chan O.C., Lee K.H., O W.S., Chow P.H. (2008) Absence of paternal accessory sex glands dysregulates preimplantation embryo cell cycle causes early oviductal-uterine transit in the golden hamster in vivo. Fertility and Sterility 89, 1021-1024.
23. Li Y.Y., O W.S., Tang F. (2008) Effect of ageing on the expression of adrenomedullin and its receptor component proteins in the male reproductive system of the rat. Journal of Gerontology A Biological Science and Medical Science. 62A, 1346,-1351.
24. Chan Y.F., O W.S., Tang F. (2008) Adrenomedullin in the rat testis I: Its production, actions on testosterone secretion, regulation by hCG and its interaction with endothelin 1 in the Leydig cell. Biology of Reproduction 78, 773-779.
25. Chan Y.F., Tang F., O W.S. (2008) Adrenomedullin in the rat testis II: Its production, actions on testosterone secretion, regulation by hCG and its interaction with endothelin 1 in the Sertoli cell. Biology of Reproduction 78, 780-785.
26. Li Y.Y., Li L., Hwang I.S.S., Tang F., O W.S. (2008) Co-expression of adrenomedullin and its receptors in the reproductive system of the rat: effects on steroids secretion in rat ovary. Biology of Reproduction 79, 200-208.