背景:SH3和多个锚蛋白重复结构域蛋白3(SHANK3)单基因突变或缺乏导致过度的刻板行为和社交能力受损,这经常发生在自闭症病例中。迄今为止,Shank3突变或缺失导致自闭症的潜在机制以及Shank3突变导致自闭症表型的大脑部分研究不足.下丘脑与刻板的行为和社交能力有关。p38α,大脑炎症反应的介质,被认为是某些自闭症发生的潜在基因。然而,目前尚不清楚下丘脑和p38α是否参与由Shank3突变或缺陷引起的自闭症的发展。
方法:使用京都基因和基因组百科全书(KEGG)途径分析和免疫印迹来评估Shank3敲除(Shank3-/-)小鼠下丘脑中的交替信号通路。进行Home-Cage实时监测测试以记录刻板行为,并使用三室测试来监测小鼠的社交能力。使用腺相关病毒9(AAV9)在弓状核(ARC)或刺鼠相关肽(AgRP)神经元中表达p38α。D176A和F327S突变表达组成型活性p38α。T180A和Y182F突变表达无活性的p38α。
结果:我们发现Shank3通过调节AgRP神经元中的p38α活性来控制刻板行为和社交能力。Shank3-/-小鼠下丘脑中磷酸化p38水平显著增强。始终如一,ARC或AgRP神经元中p38α的过表达在野生型(WT)小鼠中引起过度的刻板行为并损害社交能力。值得注意的是,AgRP神经元中激活的p38α会增加刻板行为并损害社交能力。相反,AgRP神经元中的失活p38α可显着改善Shank3-/-小鼠的自闭症行为。相比之下,ppopiomelanocortin(POMC)神经元中激活的p38α不会影响小鼠的刻板行为和社交能力。
结论:我们证明了SHANK3调节下丘脑磷酸化p38水平和AgRP神经元失活p38α,显着改善了Shank3-/-小鼠的自闭症行为。然而,我们没有阐明SHANK3抑制AgRP神经元p38α的生化机制。
结论:这些结果表明,Shank3缺乏通过激活AgRP神经元中的p38α信号而导致自闭症样行为,表明AgRP神经元中的p38α信号是Shank3突变相关自闭症的潜在治疗靶点。
SH3 and multiple ankyrin repeat domains protein 3 (SHANK3) monogenic mutations or deficiency leads to excessive stereotypic behavior and impaired
sociability, which frequently occur in autism cases. To date, the underlying mechanisms by which Shank3 mutation or deletion causes autism and the part of the brain in which Shank3 mutation leads to the autistic phenotypes are understudied. The hypothalamus is associated with stereotypic behavior and
sociability. p38α, a mediator of inflammatory responses in the brain, has been postulated as a potential gene for certain cases of autism occurrence. However, it is unclear whether hypothalamus and p38α are involved in the development of autism caused by Shank3 mutations or deficiency.
Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and immunoblotting were used to assess alternated signaling pathways in the hypothalamus of Shank3 knockout (Shank3-/-) mice. Home-Cage real-time monitoring test was performed to record stereotypic behavior and three-chamber test was used to monitor the sociability of mice. Adeno-associated viruses 9 (AAV9) were used to express p38α in the arcuate nucleus (ARC) or agouti-related peptide (AgRP) neurons. D176A and F327S mutations expressed constitutively active p38α. T180A and Y182F mutations expressed inactive p38α.
We found that Shank3 controls stereotypic behavior and
sociability by regulating p38α activity in AgRP neurons. Phosphorylated p38 level in hypothalamus is significantly enhanced in Shank3-/- mice. Consistently, overexpression of p38α in ARC or AgRP neurons elicits excessive stereotypic behavior and impairs sociability in wild-type (WT) mice. Notably, activated p38α in AgRP neurons increases stereotypic behavior and impairs
sociability. Conversely, inactivated p38α in AgRP neurons significantly ameliorates autistic behaviors of Shank3-/- mice. In contrast, activated p38α in pro-opiomelanocortin (POMC) neurons does not affect stereotypic behavior and
sociability in mice.
We demonstrated that SHANK3 regulates the phosphorylated p38 level in the hypothalamus and inactivated p38α in AgRP neurons significantly ameliorates autistic behaviors of Shank3-/- mice. However, we did not clarify the biochemical mechanism of SHANK3 inhibiting p38α in AgRP neurons.
These results demonstrate that the Shank3 deficiency caused autistic-like behaviors by activating p38α signaling in AgRP neurons, suggesting that p38α signaling in AgRP neurons is a potential therapeutic target for Shank3 mutant-related autism.