Dr. Yen, Jeffrey J.Y. 嚴仲陽 博士

RESEARCH

1) Epithelial Barrier Integrity and Skin Microbiota in Kojak Mice

Atopic dermatitis (AD) is prevalent in modern society, especially in infant and child, and causes a long-term effect in life, development and learning. AD is a complex chronic inflammatory skin disorder that results from intimate interactions among genetic predisposition, host environment, skin barrier defects, and immunological factors. However, a clear genetic roadmap leading to atopic dermatitis remains to be fully explored. From a genome-wide mutagenesis screen, deficiency of ZDHHC13, a palmitoylacyl transferase, has previously been shown to be associated with skin and multitissue inflammatory phenotypes. Genetic and immunological studies revealed that this dermatitis is a keratinocyte-cell autonomous disorder, and is not caused by adaptive immunity, nor by TNF-a, nor IL-1b. To clarify the importance of palmitoylation enzyme activity and its substrates, we generated knock-in mice to destroy the enzymatic site of ZDHHC13 protein and the results suggested that knock-in mice phenocopy the knock-out mice. Further quantitative tandem mass spectra revealed that multiple pathways are regulated by ZDHHC13, including filaggrin degradation and hydrolysis pathways. On the other hand, to study how skin microbiota cross-talk with the defective barrier, we established a cleaner SPF room that can prevent skin inflammation of Kojak mice, like in Germ-free room, and currently is studying the bacterial dysbiosis. Our future goal will include identification of dysbiosis and microbiota functional composition responsible for skin inflammation. Seeking for the underlying mechanism of dysbiosis-associated skin inflammation and development of innovative therapeutics to treat human atopic dermatitis are our final goals.

1. Song IW, Li WR, Chen LY, Shen LF, Liu KM, Yen JJ, Chen YJ, Chen YJ, Kraus VB, Wu JY, Lee MT, Chen YT. Palmitoyl acyltransferase, Zdhhc13, facilitates bone mass acquisition by regulating postnatal epiphyseal development and endochondral ossification: a mouse model. PLoS One. 2014 Mar 17;9(3):e92194. doi:10.1371/journal. pone. 0092194.
 

2. Liu KM, Chen YJ, Shen LF, Haddad AN, Song IW, Chen LY, Chen YJ, Wu JY, Yen JJ, Chen YT. Cyclic Alopecia and Abnormal Epidermal Cornification in Zdhhc13- Deficient Mice Reveal the Importance of Palmitoylation in Hair and Skin Differentiation. J Invest Dermatol. 2015 Nov;135(11):2603-10. doi: 10.1038/jid. 2015.240. 
 

3. Shen LF, Chen YJ, Liu KM, Haddad ANS, Song IW, Roan HY, Chen LY, Yen JJY, Chen YJ, Wu JY, Chen YT. Role of S-Palmitoylation by ZDHHC13 in Mitochondrial function and Metabolism in Liver. Sci Rep. 2017 May 19;7(1):2182. doi: 10.1038/s41598-017-02159-4.
 

4. Chen LY, Yang-Yen HF, Tsai CC, Thio CL, Chuang HL, Yang LT, Shen LF, Song IW, Liu KM, Huang YT, Liu FT, Chang YJ, Chen YT, Yen JJ. Protein Palmitoylation by ZDHHC13 Protects Skin against Microbial-Driven Dermatitis. J Invest Dermatol. 2017 Apr;137(4):894-904. doi: 10.1016/j.jid.2016.12.011. Epub 2016 Dec 23. 

2) CBAP acts as a novel oncoprotein in human T cell acute lymphoblastic leukemia

A relative high frequency of relapse remains a clinical enigma for cure of T-cell acute lymphoblastic leukemia (T-ALL) patients, which has recently been implicated with heterogeneous dysregulated signaling profiles. Recently, we demonstrated that GM-CSF/IL-3/IL-5 receptor common b-chain-associated protein (CBAP) is highly expressed in many human T-ALL cell lines and is required to bolster leukemia cell in vitro proliferation and in vivo leukemogenesis in xenograft mouse model. Down-regulation of CBAP markedly restrains expansion of leukemia cells and alleviates disease aggravation of leukemic mice. Transcriptomic profiling and biochemical analyses reveal that CBAP acts as a key regulator of Raf-MEK-ERK and Akt-mTORC1 signaling pathways to control leukemia cell growth. Here we further found that CBAP physically associates with Akt and TSC2 through independent domains, and serves as a scaffold protein to facilitate Akt-dependent TSC2 phosphorylation, leading to elevated Rheb-GTP loading and subsequent activation of mTORC1 signaling. Disruption of this tripartite complex through ectopic expression of N-terminal 26 residues of CBAP shows a relieve of Akt-mediated TSC2 phosphorylation, resulting in suppression of leukemia cell growth. Taken together, our findings uncover CBAP a novel oncogenic contribution to T-ALL leukemogenesis and a functional role in regulation of Akt-TSC2-mTORC1 signaling for leukemia cell proliferation, and may provide a therapeutic strategy to suppress many types of Akt-TSC2-mediated cancers.

1. Chiang YJ, Ho KC, Liao WT, Liu CS, Chen YG, Ho CL, Huang SF, Shih LY, Yang-Yen HF, Yen JJ. CBAP regulates the Rheb-GAP activity of TSC2 complexes by promoting Akt-dependent TSC2 phosphorylation and TSC1 displacement. 2017. In revision.

研究介紹

1. 皮膚障壁缺陷與皮膚菌相互動在異位性皮膚炎扮演的角色

人類異位性皮膚炎好發於現代化的社會，尤其是嬰幼兒，對於病童造成生活、成長、及學習上不良的影響。異位性皮膚炎是由遺傳性因子、居住環境、皮膚障蔽缺陷及免疫因子密切反應所造成的皮膚慢性發炎疾病，但是確切致病機制仍然不是非常清楚。過去全基因體突變研究指出Zdhhc13基因，生產一個蛋白棕梠酸化酶，缺陷時造成皮膚及其他多種器官發炎症狀。最近我們的研究指出ZDHHC13是完整皮膚障蔽所必需的，缺少ZDHHC13蛋白使得小鼠易受未知環境細菌群聚，造成皮膚發炎及類異位性皮膚炎疾病。遺傳學及免疫學研究顯示皮膚發炎是角質細胞缺陷造成，且非後天免疫也非TNF-a 或 IL-1b引發的。為了進一步了解蛋白棕梠酸化酶的角色及其酵素受質的重要性，我們製造基因踢進小鼠，只破壞酵素活性但保留酵素蛋白。初步分析顯示無活性ZDHHC13小鼠的症狀與傳統基因剔除小鼠幾乎相同。因此我們以定量型蛋白體技術尋找蛋白棕梠酸化酶最重要的酵素受質及生化途徑。目前發現filaggrin 熟成及降解途徑可能是ZDHHC13蛋白的重要標的，我們正在進行實驗證明中。另外體表菌相如何與功能缺陷的皮膚對話，造成乾淨的SPF 房無皮膚病而較低等級的SPF房有皮膚病，是我們未來積極探索的目標。包括將基因剔除的無菌鼠接種不同等級鼠房的菌相或純化的菌種，研究皮膚或免疫細胞的反應，並且進行菌種全基因體定序以探討可能免疫刺激因子或毒性代謝產物的存在。最後純化並分析發炎刺激因子的生化及免疫功能，再證明菌相對於細胞的作用機轉。此新穎發炎機轉的確認可以作為發展治療人類異位性皮膚炎的新標的。

2. CBAP acts as a novel oncoprotein in human T cell acute lymphoblastic leukemia

現今在臨床上對於急性T淋巴白血病（T-ALL）的治療， 發現病患仍有高頻率的復發比例情形，是臨床上面臨的最大挑戰，而最近發現此情形與血癌細胞的多樣性訊息傳遞路徑被活化有相關。我們最近的研究發現， 顆粒性血球細胞/巨噬細胞聚落刺激因子/第三介白素/第五介白素受體共同乙型鏈結合蛋白(CBAP) 在許多急性T淋巴白血病細胞株中有高量的表現，而且CBAP蛋白對於T-ALL細胞與小鼠體內癌化的過程佔有重要不可或缺的角色。干擾或剔除CBAP的表現可以顯著的抑制血癌細胞的生長且緩和小鼠的血癌癌化過程。在基因表現與生化分析中，顯示CBAP在Raf-MEK-ERK與Akt-mTORC1訊息傳遞路徑中是一關鍵的調控者，可透過對此路徑的控制來影響細胞生長功能。在本此期中報告裡，我們進一步發現CBAP蛋白可以透過不同的位置與Akt和TSC2有相互的結合功能，他像是一個鷹架功能蛋白可以協助Akt對於TSC2的磷酸化作用，進而增強Rheb-GTP的量以及下游的mTORC1訊息活化。當我們在細胞裡大量表現CBAP的N端26個氨基酸片段，我們發現他可以破壞Akt-CBAP-TSC2此三體蛋白結合的構造，因而削弱Akt對於TSC2的磷酸化作用，導致血癌細胞的生長受到抑制。總的來說，我們的發現揭開CBAP蛋白的新功能，在急性T淋巴白血病的小鼠模式中是一個新興的癌症基因，並且提供一個訊息傳遞的分子機制來闡明CBAP影響Akt-TSC2-mTOR的活化進而促進血癌疾病的機轉，以及可能的治療策略。

★ Patent Application:

1. PEPTIDES FOR USE IN INTERFERING WITH AKT-TSC2-MTORC1 SIGNAL TRANSDUCTION AND SUPPRESSING TUMOR GROWTH.  (Provisional Patent)

Inventors: Jong-Young Yen and Yun-Jung Chiang; Applicant: Academia Sinica, Taiwan.

Filing date: 06/17/2017. Application number: 62/521,824. Confirmation number: 6823.

2.  JAK AND HDAC DUAL-INHIBITOR COMPOUNDS. (PCT Patent) 2017.

Inventors: Brian William Dymock; Eugene Guorong Yang; Jong-Young Yen; Tan Eng Chong. Assignee: National University of Singapore and Academia Sinica