Stakkestad Øystein, Heyward Catherine, Lyngstadaas Ståle Petter, Medin Tirill, Vondrasek Jiri, Lian Aina-Mari, Pezeshki Gita, Reseland Janne Elin
Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo, Norway.
Department of Nursing and Health Promotion, Faculty of Health Sciences, OsloMet - Oslo Metropolitan University, Norway.
Heliyon. 2018 Dec 24;4(12):e01075. doi: 10.1016/j.heliyon.2018.e01075. eCollection 2018 Dec.
Transcriptional regulatory elements in the ameloblastin (AMBN) promoter indicate that adipogenesis may influence its expression. The objective here was to investigate if AMBN is expressed in adipose tissue, and have a role during differentiation of adipocytes.
expression was examined in adipose tissue and adipocytes by real-time PCR and ELISA. Distribution of ameloblastin was investigated by immunofluorescence in sections of human subcutaneous adipose tissue. The effect of recombinant proteins resembling AMBN and its processed products on proliferation of primary human pre-adipocytes and murine 3T3-L1 cell lines was measured by [H]-thymidine incorporation. The effect on adipocyte differentiation was evaluated by the expression profile of the adipogenic markers PPARγ and leptin, and the content of lipids droplets (Oil-Red-O staining).
AMBN was found to be expressed in human adipose tissue, human primary adipocytes, and in 3T3-L1 cells. The C-terminus of the AMBN protein and a 45 bp shorter splice variant was identified in human subcutaneous adipose tissue. The expression of AMBN was found to increase four-fold during differentiation of 3T3-L1 cells. Administration of recombinant AMBN reduced the proliferation, and enhanced the expression of PPARγ and leptin in 3T3-L1 and human pre-adipocytes, respectively.
The AMBN C-terminus variant was identified in adipocytes. This variant may be encoded from a short splice variant. Increased expression of AMBN during adipogenesis and its effect on adipogenic factors suggests that AMBN also has a role in adipocyte development.
成釉蛋白（AMBN）启动子中的转录调控元件表明脂肪生成可能影响其表达。本研究旨在探讨AMBN是否在脂肪组织中表达，以及在脂肪细胞分化过程中是否发挥作用。
通过实时聚合酶链反应（PCR）和酶联免疫吸附测定（ELISA）检测脂肪组织和脂肪细胞中的表达情况。通过免疫荧光法研究人皮下脂肪组织切片中成釉蛋白的分布。采用[H] - 胸腺嘧啶核苷掺入法检测重组AMBN及其加工产物对原代人脂肪前体细胞和小鼠3T3 - L1细胞系增殖的影响。通过脂肪生成标志物过氧化物酶体增殖物激活受体γ（PPARγ）和瘦素的表达谱以及脂滴含量（油红O染色）评估对脂肪细胞分化的影响。
发现AMBN在人脂肪组织、人原代脂肪细胞和3T3 - L1细胞中表达。在人皮下脂肪组织中鉴定出AMBN蛋白的C末端和一个短45bp的剪接变体。发现AMBN在3T3 - L1细胞分化过程中表达增加四倍。重组AMBN的施用分别降低了3T3 - L1细胞和人脂肪前体细胞的增殖，并增强了PPARγ和瘦素的表达。
在脂肪细胞中鉴定出AMBN C末端变体。该变体可能由一个短剪接变体编码。脂肪生成过程中AMBN表达增加及其对脂肪生成因子的影响表明AMBN在脂肪细胞发育中也发挥作用。
