PTD-hFOXP3 protein acts as an immune regulator to convert human CD4(+)CD25(-) T cells to regulatory T-like cells.
Regulatory T cells (Tregs) are critical for maintaining self-tolerance and homeostasis, and have potential application in clinical disease therapy, such as autoimmune diseases and transplant rejection, but their numbers are limited. FOXP3 is a key transcription factor controlling Tregs development and function. Although transfection of CD4(+)CD25(-) lymphocytes with the FOXP3 gene can convert them to Treg-like cells, there is the risk of insertional mutagenesis and thus an alternative to genetic intervention is sought. The protein transduction domain (PTD) from the HIV transactivator of transcription is a useful tool to deliver protein to the cytoplasm and nucleus. In this study, we generated a fusion protein linking the human FOXP3 to PTD (PTD-hFOXP3), and explored its function in T cells. The results showed that the PTD rapidly and effectively delivered the hFOXP3 protein into cells where it localized not only in the cytoplasm, but also to the nucleus. PTD-hFOXP3-transduced Jurkat cells (human T lymphoma cell line) and CD4(+)CD25(-) T cells failed to proliferate and produce IL-2 and IFN-γ, but produced large amounts of the cytokines IL-4, IL-10, and TGF-β, in response to TCR stimulation in vitro. PTD-hFOXP3-transduced CD4(+)CD25(-) T cells also expressed high levels of CTLA-4 and low levels of CD25 after stimulation. Most importantly, PTD-hFOXP3-transduced T cells inhibited the proliferation of activated CD4(+)CD25(-) T cells. Furthermore, chromatin immunoprecipitation assays demonstrated that PTD-hFOXP3 can bind with the IL-2 gene promoter and repress the expression of IL-2. These results indicate that PTD-hFOXP3 has the capability to convert conventional T cells to Treg-like cells.
Department of Immunology, School of Medical Science and Laboratory Medicine, Key Discipline of Clinical Medical Science of Jiangsu Province, Jiangsu University, Zhenjiang 212013, Jiangsu, China.
Xia
X
Liu
Xun
X
Xu
Xin
X
Lin
Yuxiang
Y
Tian
Baoju
B
Ji
Sheng
S
Xia
Sanrong
S
Xu
Qing
Q
Yin
Miaomiao
M
Zhang
Zhijun
Z
Jiao
Shengjun
S
Wang
Huaxi
H
Xu
Qixiang
Q
Shao
D021581:Active Transport, Cell Nucleus; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D060908:CTLA-4 Antigen / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D047369:Chromatin Immunoprecipitation; D003593:Cytoplasm / Q000378:metabolism; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000276:immunology*; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006678:HIV / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit / Q000235:genetics / Q000378:metabolism; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary / Q000235:genetics; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000166:cytology* / Q000276:immunology; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism*
D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508594:IL2 protein, human; C508017:IL2RA protein, human; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D054322:tat Gene Products, Human Immunodeficiency Virus; D049452:Green Fluorescent Proteins; D007371:Interferon-gamma