1. Obesity causes inflammation which increases DNMT1 expression and activity, leading to DNA hypermethylation of the adiponectin gene promoter and reduced adiponectin expression. 2. Inhibition of DNMT with RG108 prevents obesity-induced hypermethylation of the adiponectin gene, increasing adiponectin levels and improving insulin resistance. 3. RG108 treatment in obese mice reduces adiponectin gene hypermethylation, elevates adiponectin levels, and improves glucose tolerance and insulin signaling without affecting body weight or organ function.

1. NATURE COMMUNICATIONS
Obesity-induced DNA hypermethylation of the adiponectin
gene mediates insulin resistance
IF:11.47, Published online 2015 Jul 3
Xingyun Wang

2. Abstract
1.肥胖——促炎症因子——DNMT1表达/活性升高——脂联素启动子
特定区域DNA高甲基化——脂联素表达减少
2.DNMT抑制剂——抑制肥胖（DNMT1激活）引起的——葡萄糖不
耐受/胰岛素抵抗
3.调节DNMT1活性可以作为肥胖相关疾病治疗的新策略

3. Background
Adiponectin

4. Adiponectin Signaling and Metabolic Syndrome. Prog Mol Biol Transl
Sci. 2014;121:293-319
代谢组织：促进
葡萄糖利用/脂
肪酸氧化
减少脂质聚集、
预防动脉粥样硬
化
6-磷酸葡萄糖激酶、固醇
调节元件、胰岛素受体底
物
保护内皮细胞

5. Plasma adiponectin levels have also been reported to be reduced in obese humans, particularly those with
visceral obesity, and to correlate inversely with insulin resistance. Prospective and longitudinal studies have
shown that lower adiponectin levels are associated with a higher incidence of diabetes.
Adiponectin and Adiponectin Receptors. Endocrine Reviews 26(3):439–451.

6. Result1: Adiponectin promoter is hypermethylated
in obese subjects.
脂联素水平发现显著改变，而脂联素调节因子表达水平变化
无统计学差异。
检测脂联素启动子区域的甲基化水平（BSP法）
？

7. Result1:Adiponectin promoter is hypermethylated in obese subjects.
R2 R1
1.在高脂饮食以及db/db鼠中R2区域明显高甲基化
2.脂联素mRNA表达量与甲基化水平负相关
1.R1区域无明显变化
2.未见相关性

8. (补充材料)
上游的PPARγ, C/ebpα, and TNFα的启动子甲基化水平，均未受到影响

9. Result2: DNMT1 governs adiponectin gene expression via R2 methylation.
检测了3种甲基转移酶：DNMT1，DNMT3A和
DNMT3B（补充材料），仅DNMT1的表达与脂
联素的mRNA表达量相关
人体水平检测BMI与脂肪组织中DNMT1表达量相关性

10. Result2:DNMT1 governs adiponectin gene expression via R2methylation.
R2 R1
3T3-L1细胞中
沉默DNMT1，脂联素表达量增高
过表达DNMT1，~下降
R2区域的甲基化位点

11. Result3:Inflammatory cytokines promote DNA methylation at the R2.
pro-inflammatory cytokines
endoplasmic reticulum stress
mitochondrial dysfunction
hypoxicenvironment
DNMT relative enzymatic
activity.
10 ng/m,24h
10 ng/m,24h
Although the above factors potently suppressed
adiponectin gene expression, only pro-inflammatory
cytokines such as tumour necrosis factor (TNFα) and
interleukin (IL)-1β were able to induce Dnmt1 expression
and activity

12. R2 R1
Result3:Inflammatory cytokines promote DNA methylation at the R2.

13. Result4:DNMT inhibition alleviates the effect of TNFα on adiponectin.
RG108, a DNMT inhibitor.
In adipocytes, RG108 decreased TNFα-induced
DNMT1 activity, while Dnmt1 mRNA level was
elevated by TNFα

14. Result4:DNMT inhibition alleviates the effect of TNFα on adiponectin.
In 3T3-L1 adipocytes, DNMT1 was
suppressed by small interfering RNA.
The cells were then incubated with
or without TNFα (10 ng/ml) for 24 h
(n=3).
mRNA levels of adiponectin, Dnmt1
and Mcp-1 in negative control (NC)
or DNMT1 suppressed 3T3-L1
adipocytes.
Quantification of the 5-
mC levels in the
adiponectin promoter R2
and R1.

15. Result5:RG108 elevates adiponectin levels by the reduction of R2 DNA
methylation in db/db mice.
(vehicle , 1% DMSO)
WAT
Serum
R2 DNA methylation levels
血清脂联素低聚复合物的相对水平
Correlation between R2 DNA methylation and adiponectin mRNA levels

16. Result6:RG108 improves insulin resistance via adiponectin expression.
OGTT. After 16 h fasting Area under the curve (AUC)
Western blot of insulin signalling in liver (d) and skeletal muscle(e)
HE染色 eWAT/liver
lipogenic genes in the liver

17. Result6:RG108 improves insulin resistance via adiponectin expression.
adiponectin and leptin receptor double knockout (DKO) mice
liver,HE

18. RG108 does not influence the body weight, organ weight, and liver function in db/db and adiponectin and
leptin receptor knockout (DKO) mice and cannot suppress adipose tissue inflammation in DKO mice

19. In obesity, increased DNMT1 induces DNA hypermethylation at the particular region (R2) of
adiponectin promoter,resulting in suppression of adiponectin gene expression in adipocytes

20. 体会
思路：
深度：
技术性：
优缺点：DNMT1基因敲除