Langerhans cells (LCs), the skin residing dendritic cells (DCs), form a contiguous immune network in skin and are involved in allergy, infection, cancer, and autoimmune disease development. However, the regulatory mechanisms involved in the development and functions of LCs have not been completely elucidated. Histone deacetylases (HDACs) are enzymes that regulate gene expression by modifying chromatin structure through removal of acetyl groups from target histones or directly deacetylating non- histone proteins, and represent a key epigenetic regulatory mechanism. HDAC inhibitors (HDI) are shown to have anti-tumor and anti-inflammatory effects in a variety of diseases, in which LCs play an important role. However, the mechanisms underlying the clinical effectiveness of HDI remain largely unknown. We recently reported that the inhibition of Class I/II HDACs by Trichostatin A (TSA) regulates the homeostasis and function of LCs in vitro and in vivo and modulates the non-coding miRNA expressions in LCs, while miRNAs also control LC development and function. Our preliminary data indicate that LCs express all Class I/II HDACs. To evaluate the role of individual HDACs in LC development and function, we generated knockout (KO) mice with selective deletion of HDAC3 (Class I) or HDAC4 (Class II) in epidermal LCs. Interestingly, LC number was significantly reduced in LC-HDAC3KO mice, but unaffected in LC-HDAC4KO mice. Furthermore, LC maturation and function were altered in LC-HDAC3KO mice. Thus, we hypothesize that HDAC3 is a key epigenetic component that controls LC development and function.
In Aim 1, we will investigate the roles of HDAC3 in LC development and homeostasis, using LC-HDAC3KO mice for homeostasis after birth and using constitutive Csf1r-specific HDAC3-deletion mice (Csf1r-HDAC3) and inducible Csf1r- specific HDAC3-deletion (Csfr1.Mer-HDAC3) mice for early embryonic LC development;
Aim 2, we will investigate the roles of HDAC3 in LC function, using inducible LC- ER.HDAC3KO mice.
In Aim 3, we will elucidate the molecular mechanisms and signaling pathways by which HDAC3 regulates LC development and function, by combining cDNA array, miRNA array and ChiP-Seq techniques. The proposed studies will uncover the epigenetic regulatory mechanisms of HDAC3 in LC development and function, and may also elucidate new mechanisms for HDI therapy.

Public Health Relevance

Langerhans cells (LCs), the skin residing dendritic cells that form a contiguous immune network in skin, are involved in a variety of skin disease development, but the detailed molecular pathways regulating LC development and function remain largely unknown. Histone deacetylases (HDAC) are enzymes that regulate gene expression by modifying chromatin structure or directly deacetylating non-histone proteins. HDAC inhibitors (HDI) are shown to have anti-tumor and anti-inflammatory effects in a variety of diseases, including atopic dramatis, in which LCs play an important role. The overall goal of this proposal is to investigate the role of HDAC3 in skin LC development and function, identify HDAC3 direct gargets in LCs. The proposed studies will uncover the epigenetic regulatory mechanisms of HDAC3 in LC development and function, and may also elucidate new mechanisms for HDI therapy.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR069681-04
Application #
9613222
Study Section
Arthritis, Connective Tissue and Skin Study Section (ACTS)
Program Officer
Cibotti, Ricardo
Project Start
2016-02-15
Project End
2020-12-31
Budget Start
2019-01-01
Budget End
2019-12-31
Support Year
4
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Henry Ford Health System
Department
Type
DUNS #
073134603
City
Detroit
State
MI
Country
United States
Zip Code
48202
Wu, Xiaojun; Yang, Bin; Udo-Inyang, Imo et al. (2018) Research Techniques Made Simple: Single-Cell RNA Sequencing and its Applications in Dermatology. J Invest Dermatol 138:1004-1009
Yao, Yi; Liu, Queping; Martin, Carly et al. (2018) Embryonic Fate Mapping Uncovers the Critical Role of microRNAs in the Development of Epidermal ?? T Cells. J Invest Dermatol 138:236-239
Yao, Yi; Martin, Carly; Yin, Congcong et al. (2018) Micro RNAs are required for Langerhans cell, skin- and lung-resident macrophage ontogeny. J Allergy Clin Immunol 142:976-978.e2
Liu, Qing; Wu, Ding-Hong; Han, Ling et al. (2017) Roles of microRNAs in psoriasis: Immunological functions and potential biomarkers. Exp Dermatol 26:359-367
Wu, Dinghong; Bi, Xinling; Qu, Le et al. (2017) miRNA miR-17-92 cluster is differentially regulated in the imiqumod-treated skin but is not required for imiqumod-induced psoriasis-like dermatitis in mice. Exp Dermatol 26:82-84
Zhang, Xilin; Liu, Queping; Wang, Jie et al. (2016) TIM-4 is differentially expressed in the distinct subsets of dendritic cells in skin and skin-draining lymph nodes and controls skin Langerhans cell homeostasis. Oncotarget 7:37498-37512
Li, Guihua; Gao, Xing-Hua; Mi, Qing-Sheng (2016) TGF-?1-Smad signaling pathways are not required for epidermal LC homeostasis. Oncotarget 7:15290-1
Zhang, X; Gu, J; Yu, F-S et al. (2016) TGF-?1-induced transcription factor networks in Langerhans cell development and maintenance. Allergy 71:758-64