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學歷

美國堪薩斯州立大學腫瘤病毒學博士

專長

腫瘤病毒學、分子生物學、生物化學、細胞生物學

經歷

國立中正大學 分子生物研究所 教授 - 2000.8-迄今

國立中正大學 理學院院長 ─ 2006.6-2009.7

國立中正大學 生物技術暨工程中心主任 ─ 2001.8-2008.7

國立中正大學 分子生物研究所 創所所長 ─ 2000.8-2003.7

中山醫學大學 醫學系微生物暨免疫學科 科主任 ─ 1995.8-2000.7

中山醫學大學 醫學系微生物暨免疫學科 教授 ─ 1996.8-2000.7

中山醫學大學 圖書館 館長 ─ 1997.8-1998.7

中山醫學大學 醫學系微生物暨免疫學科 副教授 ─ 1993.8-1996.7

美國堪薩斯州立大學生物系腫瘤病毒組博士後研究員 ─ 1993.1-1993.7

曾服務之委員會

中華民國細胞及分子生物學學會 第七屆理事

國科會 生物暨醫學學門專題研究計畫 複審委員

國際病毒命名委員會委員(Member of International Viral Taxonomy Committee)

國科會基因體醫學國家型科技計畫“正子斷層掃描基因探針影核心設施”使用者委員會委員兼召集人

神經病毒學期刊(Journal NeuroVirology) 編輯委員

行政院中部聯合服務中心醫療衛生諮詢委員

南部科學工業園區管理局“創新研究發展計畫獎助案審核小組委員”

病毒學期刊、醫學病毒期刊、病毒研究法期刊、神經病毒學期刊以及生物科技期刊審查委員

曾獲獎情形

中山醫學大學 傑出研究獎

國科會 甲種研究獎

中正大學 追求學術卓越研究獎

研究領域

人類多瘤性病毒感染之分子研究

人類多瘤性病毒 (polyomavirus) 屬於DNA腫瘤病毒,包括JC病毒及BK病毒。該病毒為無套膜 (non-envelope) 病毒,病毒顆粒成份含有主要殼體蛋白VP1 (75%)、次要殼體蛋白VP2及VP3 (各約5%) 以及病毒基因組 (genome) 。在病毒感染細胞早期所產生的大腫瘤抗原 (large tumor antigen; LT) 會調控病毒基因組的複製及晚期殼體蛋白的生合成。大腫瘤抗原會與細胞內RB及p53蛋白結合而導致細胞癌化。在長期免疫低下的病人,JC病毒會溶解性地感染人類腦細胞 (oligodendrocyte),引發進行性多病灶腦白質症 (progressive multifocal leukoencephalopathy; PML),因而導致病人死亡。BK病毒會感染腎臟及尿道細胞而引起腎臟炎、出血性膀胱炎及尿道炎等疾病。目前我們實驗室正致力於研究人類多瘤性病毒的致病機轉,企圖瞭解該病毒如何感染人類腦細胞、如何引發細胞病變及病毒如何在細胞內複製。到目前為止對人類多瘤性病毒的研究相當緩慢,病毒在體外培養不易為主要因素之一。在人類多瘤性病毒感染之分子研究,我們證明在還原劑及金屬螯合劑的存在下,重組病毒殼體可被瓦解成次殼體。這些外型與生理特性意味著基因重組的VP1蛋白摺疊構型 (folding) 與原始病毒蛋白構型非常相近。我們更進一步探討DNA包裝的機制,結果發現VP1的DNA包裝訊號位於N-端12個氨基酸區域。在in vivo及in vitro實驗證明該DNA包裝訊號切除後,無法包裝DNA於殼體內而形成空殼體形態。此外,我們更進一步發現VP1 N-端19個胺基酸及C-端17個胺基酸為該病毒殼體組裝所必需之胜肽區域。在JC病毒次要殼體蛋白,VP2及VP3, 我們發現VP2/3 C-端的13個胺基酸為DNA結合區域。以上這些發現對於JC病毒顆粒組裝機轉提供重要訊息。此外,以液相層析串聯式質譜儀鑑定BK病毒蛋白質的修飾之研究,研究結果顯示VP1含有9種修飾; VP2含有5種修飾; VP3含有6種修飾。這些發現將有助於未來瞭解該病毒之複製及導致腎臟衰竭之致病機轉。我們更進一步研究VP1 Ser-80及VP2 Ser-254磷酸化導致BK病毒於腎臟細胞複製之致病機轉,本研究結果證明BK病毒VP1 Ser-80及VP2 Ser-254磷酸化會讓BK病毒再活化,引起BK病毒子代在腎臟組織大量複製,導致溶解性地感染腎臟細胞,造成腎病變,最後導致腎衰竭。

基因治療

人類JC類病毒殼體做為基因治療載體

人類多瘤性病毒,JC病毒,結構蛋白VP1是主要殼體蛋白,約占病毒總蛋白量75 %。將JCV VP1基因選殖至大腸桿菌進行表達,其蛋白質表達後會自行組裝成類病毒顆粒。此類病毒顆粒可以滲透壓震盪法(osmotic shock)體外包裝運送外源性核酸,進入哺乳類細胞,表達或是抑制特定蛋白質,以影響細胞生理。此結果顯示JC病毒顆粒有可能可發展為基因輸送載體。我們利用JC病毒殼體做為人類腦神經膠瘤之基因治療,此研究利用JCV類病毒殼體包裝腫瘤抗原之反義核甘酸可促使人類神經膠原母細胞死亡。我們進一步發展出在大腸桿菌體內,表達組裝病毒殼體的同時,進行外源性的DNA包裝。這種細胞內包裝DNA的表達系統可以對包裝入的DNA有更好的保護性,也相對增加了輸送基因的效率。以此系統所生產的JCV類病毒顆粒經測試,至少可感染腎臟、腦部、肺、卵巢、大腸、骨頭、皮膚及B淋巴球等13種人類的癌細胞株,並可表達轉殖基因之蛋白產物。這些結果暗示著此基因載體可能可輸送治療性基因以治療特定的腫瘤。為增加此基因載體的應用性,我們進一步分析在大腸桿菌表達系統中,JCV類病毒顆粒可以包裹的DNA長度。實驗結果顯示,約10 kb左右的DNA長度可以被包入殼體顆粒內。這結果顯示利用JC類病毒殼體作為基因載體,在治療性基因或組織專一性的啟動子的選擇有更大的彈性。大腸桿菌是一種相當廉價的蛋白質表達系統,在此系統下表達出攜帶有外源性基因的JCV類病毒顆粒,只要以蔗糖或氯化銫梯度進行超高速離心,即可被純化出,製備過程簡單且經濟。我們利用此方法將外源性基因如螢光蛋白質體(pEGFP-N3 plasmid)或人類單純疱疹病毒(HSV-1)自殺性基因質體(pUMVC1-tk),與已含有 JC VP1 基因質體之大腸桿菌直接進行轉染(transformation),使重組性大腸桿菌內同時含有 JC VP1 基因質體及 pEGFP-N3 plasmid 或 pUMVC1-tk ,並在誘發 JC VP1 蛋白表達後,在大腸桿菌中自行組裝成類病毒顆粒時,外源性基因質體可同時包裝進入類病毒殼體內,並將其分別命名為 gfp-VLP 及 tk-VLP。此 gfp-VLP 或 tk-VLP可成功感染人類大腸癌細胞(colon adenocarcinoma cell,COLO-320 HSR),使 GFP 可在COLO-320 HSR細胞內表達,與促使大腸癌細胞在含無毒性病毒治療藥物(ganciclovir,GCV)之培基中造成細胞毒殺效果。而在裸鼠動物實驗模式中,利用尾部靜脈注射方式,注射 gfp-VLP 到 COLO-320 HSR 皮下接種形成腫瘤之裸鼠體內,可在腫瘤區域內觀察到綠色螢光蛋白表達,並且將 tk-VLP 全身性注射到 COLO-320 HSR 皮下腫瘤之裸鼠體內,配合腹腔注射 GCV,可觀察到 COLO-320 HSR 皮下腫瘤之生長受到抑制,腫瘤之體積比控制組明顯減小,此研究之結果證明,未來可利用 JCV VP1 VLP 運送治療基因,做為人類大腸癌基因治療載體。因此,未來我們也將企圖利用該病毒殼體做為基因治療載體進行研究。此基因重組之病毒殼體不僅有助於JC病毒感染之分子研究,而且可應用於疫苗、檢驗試劑及基因治療載體之臨床使用。

論文與著作

  1. Yeh, C-M, P-C Chen, H-Y Hsieh, Y-C Jou, C-T Lin, M-H Tsai, W-Y Huang, Y-T Wang, R-I Lin, S-S Chen, C-L Tung, S-F Wu, D.C. Chang, C-H Shen, C-D Hsu and M W.Y. Chan. 2015. Methylomics analysis identifies ZNF671 as an epigenetically repressed novel tumor suppressor and a potential non-invasive biomarker for the detection of urothelial carcinoma. Oncotarget , 6(30), 29555-72.
  2. Fang, C.-Y., Y.-D. Tsai, M.-C. Lin, M. Wang, P.-L. Chen, C.-N. Chao, Y.-L. Huang, D.C. Chang and C.-H. Shen. 2015. Inhibition of human bladder cancer growth by a suicide gene delivered by JC polyomavirus virus-like particles in a mouse model. Journal of Urology, 193(6), 2100-6.
  3. Fang, C.-Y., C.-H. Shen, M. Wang, P.-L. Chen, M. Chan, P.-H. Hsu and D.C. Chang. 2015. Global Profiling of Histone Modifications in the Polyomavirus BK Virion Minichromosome. Virology, 483, 1-12.
  4. Chao, C.-N., Y.-L. Huang, M.-C. Lin, C.-Y. Fang, C.-H. Shen, P.-L. Chen, M. Wang, D.C. Chang and C.-E. Tseng. 2015. Inhibition of human diffuse large B-cell lymphoma growth by JC polyomavirus-like particles delivering a suicide gene. Journal of Translational Medicine. 27;13(1):29. Epub ahead of print.
  5. Fang, C.-Y., C.-H. Shen, M. Wang, P.-L. Chen, M. Chan, P.-H. Hsu and D.C. Chang (2015). Global Profiling of Histone Modifications in the Polyomavirus BK Virion Minichromosome. Virology. Accepted
  6. Fang, C.-Y., Y.-D. Tsai, M.-C. Lin, M. Wang, P.-L. Chen, C.-N. Chao, Y.-L. Huang, D.C. Chang and C.-H. Shen. 2015. Inhibition of human bladder cancer growth by a suicide gene delivered by JC polyomavirus virus-like particles in a mouse model. The Journal of Urology. Doi:10.1016/j.juro.2015.01.084. Epub ahead of print.
  7. Tseng, C.-E., C.-M. Yeh, C.-Y. Fang, J. Shay, P.-L. Chen, M.-C. Lin, D.C. Chang and M. Wang. 2014. Detection of human JCPyV and BKPyV in diffuse large B-cell lymphoma of the GI tract. European Journal of Clinical Microbiology and Infectious Diseases. 33:665-672.
  8. Lin, M.-C., M. Wang, C.-Y. Fang, P.-L. Chen, C.-H. Shen, D.C. Chang. 2014. Inhibition of BK virus replication in human kidney cells by BK virus large tumor antigen-specific shRNA delivered by JC virus-like particles. Antiviral Research. 103:25–31.
  9. Tsay, G.J.,Y.-F. Hsieh, M. Wang, D.C. Chang, J.T. Chang and M. Zouali. 2013. Targeting the IL-10 pathway by RNA interference has beneficial effects o the development of experimental lupus. European Journal of Inflammation. 11:43-54
  10. Liaw, Y.-C., C.-H. Chen, K.-H. Shu, C.-Y. Fang, W.-C. Ou, P.-L. Chen, Shen, M.-C. Lin, D.C. Chang, M. Wang. 2012. Recombined sequences between the non-coding control regions of JC and BK viruses found in the urine of a renal transplantation patient.Virus Genes. 45:581-584.
  11. Fang, C.-Y., P.-Y. Lin, W.-C. Ou, P.-L. Chen,.C.-H. Shen, D.C. Chang, M. Wang. 2012. Analysis of the size of DNA packaged by the human JC virus-like particle. Journal of Virological Methods. 182:87– 92.
  12. Chang, C.-F., M. Wang, W.-C. Ou, P.-L. Chen, C.-H. Shen, P.-Y. Lin, C.-Y. Fang, D.C. Chang. 2011. Human JC virus-like particles as a gene delivery vector. Expert Opinion on Biological Therapy. 11:1169-1175.
  13. Chen, P.-C. M.-H. Tsai, S. K.H. Yip, Y.-C. Jou, C.-F. Ng, Y. Chen, X. Wang, W. Huang, C.-L. Tung, G.C.-W. Chen, M. M.-S. Huang, J.H.M. Tong, E.-J. Song, D.C. Chang, C.-D. Hsu, K.-F. To, C.-H. Shen and M.W.Y. Chan. 2011. Distinct DNA methylation epigenotypes in bladder cancer from different Chinese sub-populations and its implication in cancer detection using voided urine. BMC Medical Genomics. 4:45.
  14. Shen, C.-H, J.-D. Wu, C.-D. Shu, Y.-C. Jou, C.-T. Lin, M. Wang, S.-F. Wu, M.W.Y. Chan, M.-K. Chiang, C.-Y. Fang, and D.C. Chang. 2011. The high incidence of JC virus infection in urothelial carcinoma tissue in Taiwan. Journal of Medical Virology. 83: 2191–2199.
  15. Chen, P.-L., P.-H. Hsu, C.-Y. Fang, C.-F. Chang, W.-C. Ou, M. Wang and D.C. Chang. 2011. Phosphorylation of Ser-80 of VP1 and Ser-254 of VP2 are essential for human BK virus propagation in tissue culture.Journal of General Virology. 92:2637-2645.
  16. C.-Y. Fang, M. Wang, C.-Y. Fang, P.-L. Chen, S.-F. Wu, M.-W.Y. Chan and D.C. Chang. 2011. Analysis of DNA methylation in human BK virus. Virus Genes. 43, 201-207.
  17. Chen, C.-H., M.-C. Wen, M. Wang, J.-D. Lian, C.-H. Cheng, M.-J. Wu, T.-M. Yu, Y.-W. Chuang, D.C. Chang and K.-H. Shu. 2010. High Incidence of Malignancy in Polyomavirus-Associated Nephropathy in Renal Transplant Recipients. Transplantation Proceedings. 42:817–818.
  18. Chou, M.-I., M. Wang, J.-T. D.C. Chang Chang , Y-F. Hsieh, M. Zoua and G. J. Tsay. 2010.Efficient transfection of IL-10 RNAi by JC virus as a gene delivery vector in both murine macrophage cells and BALB/c mice. The Journal of Biomedical Science. 17:51-59.
  19. Shen, C.-H., H.-Y. Hsieh, Y.-H. Wang, S.-Y. Chen, C.-L. Tung, J.-D. Wu, C.-T. Lin, C.-D. Hsu and D.C. Chang. 2010. High DKK1 expression in patients with urothelial carcinoma.Experimental and Therapeutic Medicine. 1:893-898.
  20. Fang, C.-Y., H.-Y. Chen, M. Wang, P.-L. Chen, C.-F. Chang, L.-S. Chen, C.-H. Shen, W.-C. Ou, M.-D. Tsai, P.-H. Hsu, and D.C. Chang. 2010. Global Analysis of Modifications of the Human BK Virus Structural Proteins by LC-MS/MS. Virology. 402:164-176.
  21. Chen, L.-S., M. Wang, W.-C. Ou, C.-Y. Fung, P.-L. Chen, C.-F. Chang, W.-S. Huang, J.-Y. Wang, P. Y. Lin and D.C. Chang. 2010. Efficient gene transfer using the human JC virus-like particle that inhibits human colon adenocarcinoma growth in a nude mouse model. Gene Therapy. 17:1033-1041.
  22. Chang, T.-L., M.-T. Yu, Y.-C. Ho, C.-H. Shen, D.-W. Liu, Chin Li, D.C. Chang, S.-F. Wu. 2010. Dysfunction of natural killer cells in patients with transitional cell carcinoma. Cancer Letter. 291:39-45.
  23. Lin P.-Y, C.-Y Fung, F.-P. Chang, W.-S. Huang, W.-C. Chen, J.-Y. Wang, D.C. Chang. 2008. Prevalence and genotype identification of human JC virus in colon cancers in Taiwan. Journal of Medical Virology. 80:1828-1834.
  24. Chen, M.-H, S.-H. Chen, Q.-F., Wang, J.-C., Chen, D.C. Chang, S.-L. Hsu, Y.-W. Liu. 2008. The molecular mechanism of gypenosides-induced G1 growth arrest of rat hepatic stellate cells. J. Ethnopharmacol. 117:309-317.
  25. Wen, M.-C., J.-D. Lian, H.-R. Chang, K.-H. Su, M.-J. Wu, C.-H. Chen, Y.-J. Jan, J. Wang, D.C. Chang. 2007. Polyomavirus Nephropathy in renal allograft: prevalence and correlation of histology and graft failure. Nephrology. 12:615-619.
  26. Chang, Y.-Y., M.-.Y. Lan, C.-H. Peng, H.-S. Wu, D.C. Chang, J.-S. Liu. 2007. Progressive multifocal leukoencephalopathy in an lmmunocompetent Taiwanese patient. J. Formos. Med. Assoc. 106:60-64.
  27. Chen M.-H., J.-C. Chen, C.-C. Tsai, W.-C. Wang, D.C. Chang, D.-G.Tu, H.-Y. Hsieh. 2005. The role of TGF-beta 1 and cytokines in the modulation of liver fibrosis by Sho-saiko-to in rat's bile duct ligated model. J. Ethnopharmacol.97:7-13.
  28. Wang, M.-L., T.-S. Tzou, W.-C. Ou, C.-F. Chang, C.-Y. Fung, L.-S. Chen and D.C. Chang. 2004. Inhibition of SV40 LT expression in human fetal glial cells by antisense oligodeoxynucleotide delivered by JCV virus-like-particle. Human Gene Therapy. 15:1077-1090.
  29. Chen, M.-H., J.-C. Chen, C.-C. Tsai, W.-C. Wang, D.C. Chang, C.-C. Lin and H.-Y. Hsieh. 2004. Herbal Medicine: Sho-saiko-to prevents liver fribrosis induced by bile duct ligation in rats. The American Journal of Chinese Medicine. 32:195-207.
  30. Wen, M.-C., C.-L. Wang, M.-L. Wang, C.-H. Cheng, M.-J. Wu, C.-H. Chen, K.-H. Shu and D.C. Chang. 2004. Association of JC virus with tubulointerstitial nephritis in a renal allograft recipient. Journal of Medical Virology. 72:675-678.
  31. D.C. Chang. 2004. Gene delivery by JC virus-like particle.Journal of NeuroVirology. Volume 10, Supplement 2, 26, DOI: 10.1080/13550280490469699
  32. Chen, M.-H., J.-C. Chen, D.C. Chang, W.-C. Wang and H.-Y. Hsieh. 2003. Effect of Xiao-Chai-Hu-Tang on anti-oxidation and suppression of the ito cell induced by bile duct ligation in rats. Journal of International Chinese and Western Medicine. 4:45-52.
  33. Huang, Y.-L., M.-L. Wang, W.-C. Ou, C.-Y. Fung, L.-S. Chen and D.C. Chang. 2003. Analysis of DNA binding activity of the JCV minor capsid protein VP2. Journal of NeuroVirology. 9:21-24.
  34. Chang, H., M.-L. Wang, R.-Tai Tsai, H.-S. Lin, J.-S. Huan, W.-C. Wang, and D.C. Chang. 2002. High incidence of JC viruria in JC seropositive older individuals. Journal of NeuroVirology. 8:1-5.
  35. Ou, W.-C., L.-H. Chen, M.-L. Wang, T.-H. Hseu and D.C. Chang. 2001. Analysis of minimal sequences on JC virus VP1 required for capsid assembly. Journal of NeuroVirology. 7:298-301.
  36. Chen, P.-L. M.-L. Wang, W.-C. OuC.-K. Lii, and D.C. Chang. 2001. Disulfide bonds stabilize JC virus capsid-like structure by protecting calcium ions from chelation. FEBS Letter. 500:109-113.
  37. Ou, W.-C., M. Wang, H. Chang, G. J. Tasy, T.-H. Hseu and D.C. Chang. 2001. Identification of a DNA encapsidation sequence for human polyomavirus pseudovirion formation. Journal of Medical Virology. 64:366-373.
  38. Chen, C.H., M.C. Wen, M.L. Wang, J.D. Lian, M.J. Wu, C.H. Cheng, K.H. Shu and D.C. Chang, 2001. A regulatory region rearranged BKV is associated with tubulointerstitial nephritis in a rejected kidney allograft. Journal of Medical Virology. 64:82-88.
  39. Wang, M.-L., R.-T. Tsai, W.-C. Ou, C.-K. Lin, G. J. Tsay, H. Chang and D.C. Chang. 2000. Treatment with cytotoxic immunosuppression agents increases urinary excretion of JCV in patients with autoimmune disease.” Journal of Medical Virology. 62:505-510.
  40. Wang, G.-Shern, C.-H. Chen, and D.C. Chang. 2000. Application of Molecular Biology in Clinical Medicine. Show-Chwan Medical Journal. 2:59-63.
  41. D.C. Chang 2000. Investigation of human polyomavirus. Life Sciences Newsletter, NSC. 14:3-5.
  42. D.C. Chang, C. Sugimoto, M.-L. Wang, R.-T. Tsai, and Y. Yogo. 1999. JC virus genotypes in the Taiwan aboriginal tribe (Bunun): implication for its population history. Archives of Virology. 144:1081-1090.
  43. Wang, M-L, T.-Y. Tzeng, C.-Y. Fung, W.-C. Ou, R.-T. Tsai, C.-H. Chen and D.C. Chang. 1999. Human anti-JC virus serum reacts with native but not denatured JC virus major capsid protein VP1. Journal of Virological Methods. 78:171-176.
  44. Ou, W.-C., M.-L. Wang, C-Y. Fung, R.-T. Tsai, P-C. Chao, T.-H. Hseu, and D.C. Chang . 1999. The major capsid protein VP1 of human JCV expressed in E. coli is able to self-assemble into a capsid-like particle and deliver exogenous DNA into human kidney cells. Journal of General Virology. 80:39-46.
  45. Tsai, R.-T., M.L. Wang, W.-C. Ou, Y.-L. Lee, S.-Y. Li, C.-Y. Fung, Y.-L. Huang, T.-Y. Tzeng, and D.C. Chang. 1997. Viruria incidence of JC virus is higher than that of BK virus in Taiwan. Journal of Medical Virology. 52:253-257.
  46. Gillock, E.T., S. Rottinghaus, D.C. Chang, X. Cai, S.A. Smiley, and R.A. Consigli. 1997. Polyomavirus major capsid protein VP1 is capable of packaging cellular DNA when expressed in the baculovirus system. Journal of Virology. 71:2857-2865.
  47. D.C. Chang, C-Y. Fung, W-C. Ou, P-C. Chao, S-Y. Li, M-L Wang, Y-L. Huang, T-Y. Tzeng, and R.-T. Tsai. 1997. Self assembly of the JC virus major capsid protein VP1 expressed in insect cells. Journal of General Virology. 78:1435-1439.
  48. Ou, W.-C., R.-T. Tsai, M.-L. Wang, C-Y. Fung, T.-H. Hseu, and D.C. Chang . 1997. Genomic cloning and sequence analysis of Taiwan-3 human polyomavirus JC virus. Journal of The Formosan Medical Association. 96:511-516.
  49. D.C. Chang, W-C. Ou, K.-K. Liao, M-L Wang, and C-Y. Fung. 1996. "Cloning, Expressing and purification of the recombinant polyomavirus VP1 and characterization of its DNA binding domain. The Chung Shan Medical Journal. 7:1-12.
  50. D.C. Chang, Z-M., Liou, W-C. Ou, R.-T. Tsai, K-Z. Wang, M-L Wang, and C-Y. Fung. 1996. Production of the antigen and the antibody of the JC virus major capsid protein VP1. Journal of Virological Methods. 59:177-187.
  51. D.C. Chang, M-L Wang, W-C. Ou, R.-T. Tsai, C.-Y. Fung, and Y.-J. Hwang. 1996. A simple method to detect human polyomavirus DNA in urine by polymerase chain reaction. Journal of Virological Methods. 58:131-136.
  52. D.C. Chang, R-T. Tsai, M-L Wang, and W-C. Ou. 1996. Different genotypes of human polyomaviruses found in patients with autoimmune diseases in Taiwan. Journal of Medical Virology. 48:204-209 .
  53. D.C. Chang, M-L Wang, W-C. Ou, M-S. Lee, H-N. Ho, and R-T. Tsai. 1996. Genotypes of human polyomaviruses in urine samples of pregnant individuals in Taiwan. Journal of Medical Virology. 48:95-101.
  54. Cai, X., D.C. Chang, and R.A. Consigli. 1994. Expression and purification of recombinant polyomavirus VP2 protein and its interactions with polyomavirus proteins. Journal of Virology. 68:7609-7613.
  55. Rodgers, R.E.D., D.C. Chang, X. Cai, and R.A. Consigli. 1994. Purification of Recombinant budgerigar fledgling disease virus VP1 capsid protein and its ability for in vitro Capsid Assembly. Journal. of Virology. 68:3386-3390.
  56. D.C. Chang, X. Cai, and R. A. Consigli. 1993. Characterization of the DNA binding properties of the polyomavirus structural proteins VP1, VP2, and VP3. Journal of Virology. 67:6327-6322.
  57. Haynes, J. I., D.C. Chang, and R.A. Consigli. 1993. Mutagenesis of the putative calcium-binding domain of the polyomavirus major capsid protein VP1. Journal of Virology. 67:2486-2495.
  58. D.C. Chang, A. Paulsen, T.C. Johnson, and R.A. Consigli. 1993. Virus protein assembly in microgravity. Advances of Space Research. 13:251-257.
  59. D.C. Chang, J.I. Haynes, J.H. Brady, and R.A. Consigli. 1993. Identification of an amino acid sequence in the polyomavirus capsid proteins that serve as nuclear localization signals. Transactions of the Kansas Academy of Science. 96:35-39.
  60. D.C. Chang, J.I. Haynes, J.N. Brady, and R.A. Consigli. 1992. Identification of a nuclear localization sequence in the polyomavirus structural protein VP2. Virology. 191:978-983.
  61. D.C. Chang, J.I. Haynes, J.H. Brady, and R.A. Consigli. 1992. The use additive and subtractive approaches to examine the nuclear localization sequence of the polyomavirus major capsid protein VP1. Virology. 189:821-827.
  62. Consigli, R.A., J.H. Haynes, D.C. Chang, L. Grenz, and D. Richter. 1992. Early events in polyoma infection: adsorption, penetration, and nuclear transport. Transactions of the Kansas Academy of Science. 95:62-69.

Our research interests

Throughout the past years, the long term goals of our laboratory are to study the epidemiology, pathology, gene delivery and molecular mechanism(s) of infection of human polyomavirus, JC virus (JCV) and BK virus (BKV). Human polyomavirus, a subfamily of the Polyomaviridae, is a small DNA tumor virus containing a closed, circular, double-stranded DNA genome which is separated into early and late coding sequences by the viral regulatory region. Capsid of polyomavirus contains the major structural protein, VP1, and the minor structural proteins, VP2 and VP3, with a diameter of 42 nm. JCV is the etiological agent of progressive multifocal leukoencephalopathy (PML), which is a fatal, sub-acute and demyelinating disease in humans. BKV is associated with hemorrhagic cystitis and interstitial nephritis in immunocompromised patients. The large tumor antigen (LT) of the virus is involved in tumorigenesis.

Findings of our previous and current studies:

1. Molecular investigation of BK virion maturation:

The viral genome contains double-stranded DNA with approximately 5 kbp and nucleosomes. The genome encodes two early proteins, large T (LT) and small t (st), and four late proteins, namely agnoprotein, VP1, VP2 and VP3. The outer shell of the polyomavirus consists of 72 VP1 pentamers that are arranged as 12 penta-coordinated and 60 hexa-coordinated to form an icosahedral structure.

Since the structural proteins of BKV have features that are needed for interaction with host cells during viral replication, the post-translational modifications (PTMs) may be involved in generating diversity, complexity, and heterogeneity across the structural proteins, which will enable them to adapt to the various interactions that are needed. However, little is known about the characteristics of BK viral proteins in this context. Modifications of BK viral proteins have been analyzed. The VP1 of BKV can be divided into sixteen subspecies by two-dimensional gel electrophoresis. Modifications of VP1, VP2 and VP3 were comprehensively identified by LC-MS/MS. The presence of various modifications including acetylation, cysteinylation, carboxymethylation, carboxyethylation, formylation, methylation, methylthiolation, oxidation, dioxidation and phosphorylation were identified. The identification of these modifications of the structural proteins should facilitate an understanding of the physiology of BKV during its life cycle (Fang et al., 2010, Virology, 402:164-176).

Biological effects of phosphorylation on the BKV structural proteins, VP1, VP2 and VP3, have been further analyzed. Phosphorylation on the BKV structural proteins was demonstrated by [32P]-orthophosphate labeling in vivo. Site-directed mutagenesis was performed to replace all phosphorylated amino acids as identified by LC-MS/MS.

The mutated BKV genomes were transfected into Vero cells for propagation analysis. The results showed that expression of the early protein LT and of the late protein VP1 by the mutants VP1-S80A, VP1-S80-133A, VP1-S80-327A, VP1-S80-133-327A, and VP2-S254A, were abolished. However, propagation of other mutants was similar to that of wild-type BKV. The results suggest that phosphorylation of Ser-80 on VP1 and Ser-254 on VP2 are crucial for BKV propagation (Chen et al., 2011, J. Gen. Virol., 92, 2637-2645).

Human BK virus may cause nephropathy due to viral replication in patients who have undergone renal transplantation. However the mechanism regulating replication of BKV is still not clear. Previous studies have suggested that epigenetic modifications may play a crucial role in virus replication. The DNA methylation profiles of five CpG sites located within promoter/enhancer regions and nine CpG sites located within early and late coding regions of the replicating BKV genome have been investigated. BKV genomic DNA from mature virions and from early and late phase of replicating BKV were examined for DNA methylation by bisulfite sequencing that covered 14 CpG sites. Our results showed that none of the examined BKV DNA from the various different stages of replication was methylated. This is the first report to analyze the methylation of BKV genomic DNA during viral replication. The results seem to indicate that methylation is not involved in regulation of BKV replication (Chang et al., 2011, Virus Genes, 43, 201-207).

2. Gene delivery and gene therapy by using the JCV VLP:

We have previously cloned and expressed the major capsid protein VP1 of JC virus in insect cells (Chang et al., 1997, J. Gen. Virol., 78:1435-1439), E. coli (Ou et al., 1999, J. Gen. Virol., 80:39-46) and yeast (Chen et al., 2001, FEBS Letter, 500:109-11314). The recombinant VP1 protein was able to self-assemble into a virus-like structure. We are able to purify the VLP with abundance and ease for further gene delivery manipulation. The VLP was able to package and deliver exogenous DNA into human kidney cells for expression (Ou et al., 1999, J. Gen. Virol., 80:39-46). For example, we are successfully delivered antisense oligodeoxynucleotide using VLP into human glioma (SVG) cells resulting in growth inhibition (Wang et al., 2004, Human Gene Therapy, 15:1077-1090). More recently, we further demonstrated that the VLP was able to deliver suicide gene (TK) into human colon carcinoma cells for gene expression and inhibiting tumor growth in a mouse model (Chen et al., 2010, Gene Therapy. 17, 1033–1041). The VLP was also able to deliver IL-10 RNAi into macrophage cells to reduce IL10 expression (Chou et al., 2010, J. Biomed. Sci.17, 51-59) for possible systemic lupus erythematosus (SLE) gene therapy. Development of a gene delivery vector using the JC VLP has been reviewed in Expert Opinion on Biological Therapy (Chang et al., 2011, 11, 1169-1175).

3. Pathology of human polyomavirus infection:

Reactivation of human polyomavirus may cause lytic infection and result in PML and nephropathology. Human immunity may play a role in the regulation of viral replication. However, the mechanism for reactivation of human polyomavirus is not fully understood. Our investigations revealed that infection of BKV and JCV was associated with urothelial carcinoma (Shen et al., 2011, J. Med. Virol., 83, 2191–2199) and colon cancers (Lin et al., 2008, J. Med. Virol., 80:1828-1834). Infection of BKV and JCV was involved in nephropathy (Wen et al., 2007, Nephrology. 12:615-619; Chen et al., 2010, Transplant. Proc., 42, 817–818). Furthermore, correlation of JCV infection and PML was also found in a PML patient in Taiwan (Chang et al., 2007, J. Formos. Med. Assoc., 106, 60-64).

In the past few years, epidemiology and clinical pathology of infection of human polyomavirus, JCV and BKV, with various diseases in Taiwan were investigated in my laboratory. Molecular mechanisms of the virus infection during the late phase of lytic infection were also studied. Our findings may provide some significant information to understand the viral pathogenesis. In addition, we also demonstrated that it is possible to develop the JCV VLP as a gene delivery vector for gene therapy in the future. The current accomplishments in my laboratory may allow us to further investigate the subtle mechanisms of human BKV infection and pathogenesis.