Identifying Function Determining Residues in Neuroimmune Semaphorin 4A.
Identifying Function Determining Residues in Neuroimmune Semaphorin 4A.
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DOI：
10.3390/ijms23063024
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发表时间：
2022-03-11
影响因子：
5.6
通讯作者：
Keegan AD
中科院分区：
文献类型：
--
作者：
Chapoval SP;Lee M;Lemmer A;Ajayi O;Qi X;Neuwald AF;Keegan AD
信号蛋白4A （Sema4A）通过参与丛蛋白B1对PBMC和CD4+ T细胞培养中的Treg细胞发挥稳定作用。Sema4A缺陷小鼠表现出过敏性气道炎症增强并伴有Treg细胞减少，而Sema4D缺陷小鼠表现出炎症减轻和Treg细胞数量增加，即使Sema4亚家族成员都参与丛蛋白B1。本研究的主要目的是：1。比较Sema4A和Sema4D蛋白对人Treg细胞的体外作用；和2。基于Sema4D同源性建模，鉴定Sema4A中与Plexin B1结合的关键功能决定残基。我们在这里报道，Sema4A和Sema4D在体外PBMC培养中对人Treg细胞显示相反的作用；Sema4D抑制CD4+CD25+Foxp3+细胞数量和CD25/Foxp3表达。Sema4A和Sema4D在体外与Plexin B1竞争性结合，因此在体内也可能这样做。基于区分可能导致功能差异的序列模式，Bayesian Partitioning with Pattern Selection （BPPS）将来自不同生物的4505个Sema结构域划分为亚群。BPPS将Sema3和Sema4划分为一个家族，并进一步将Sema4A和Sema4D划分为不同的亚家族。Sema3、sem4家族和Sema4A的特殊残基（以及Sema4D的同源性）倾向于聚集在Plexin B1结合位点周围。这表明Sema4A和Sema4D的共同和独特的残基可能介导了与Plexin B1的结合，亚家族残基介导了功能特异性。我们将sema4a特异性残基M198和F223突变为丙氨酸；值得注意的是，Sema4A中的F223与Sema4D中的丙氨酸对应。检测突变蛋白的丛蛋白b1结合和Treg刺激活性。F223A突变体在体外PBMC培养中无法刺激Treg的稳定性，尽管其结合丛蛋白B1的亲和力与WT蛋白相似。这项研究是产生具有刺激Treg细胞功能的强效突变Sema4A分子的第一步，旨在设计哮喘的免疫治疗药物。
Semaphorin 4A (Sema4A) exerts a stabilizing effect on human Treg cells in PBMC and CD4+ T cell cultures by engaging Plexin B1. Sema4A deficient mice display enhanced allergic airway inflammation accompanied by fewer Treg cells, while Sema4D deficient mice displayed reduced inflammation and increased Treg cell numbers even though both Sema4 subfamily members engage Plexin B1. The main objectives of this study were: 1. To compare the in vitro effects of Sema4A and Sema4D proteins on human Treg cells; and 2. To identify function-determining residues in Sema4A critical for binding to Plexin B1 based on Sema4D homology modeling. We report here that Sema4A and Sema4D display opposite effects on human Treg cells in in vitro PBMC cultures; Sema4D inhibited the CD4+CD25+Foxp3+ cell numbers and CD25/Foxp3 expression. Sema4A and Sema4D competitively bind to Plexin B1 in vitro and hence may be doing so in vivo as well. Bayesian Partitioning with Pattern Selection (BPPS) partitioned 4505 Sema domains from diverse organisms into subgroups based on distinguishing sequence patterns that are likely responsible for functional differences. BPPS groups Sema3 and Sema4 into one family and further separates Sema4A and Sema4D into distinct subfamilies. Residues distinctive of the Sema3,4 family and of Sema4A (and by homology of Sema4D) tend to cluster around the Plexin B1 binding site. This suggests that the residues both common to and distinctive of Sema4A and Sema4D may mediate binding to Plexin B1, with subfamily residues mediating functional specificity. We mutated the Sema4A-specific residues M198 and F223 to alanine; notably, F223 in Sema4A corresponds to alanine in Sema4D. Mutant proteins were assayed for Plexin B1-binding and Treg stimulation activities. The F223A mutant was unable to stimulate Treg stability in in vitro PBMC cultures despite binding Plexin B1 with an affinity similar to the WT protein. This research is a first step in generating potent mutant Sema4A molecules with stimulatory function for Treg cells with a view to designing immunotherapeutics for asthma.
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影响因子：
16.6
作者：
Lu N;Li Y;Zhang Z;Xing J;Sun Y;Yao S;Chen L
通讯作者：
Chen L
影响因子：
--
作者：
Chapoval, Svetlana P;Hritzo, Molly;Keegan, Achsah D
通讯作者：
Keegan, Achsah D
影响因子：
9.1
作者：
Morihana, Tetsuo;Goya, Sho;Kikutani, Hitoshi
通讯作者：
Kikutani, Hitoshi
DOI：
10.4049/jimmunol.1300486
发表时间：
2013-08-15
期刊：
Journal of immunology (Baltimore, Md. : 1950)
影响因子：
--
作者：
Dorsey NJ;Chapoval SP;Smith EP;Skupsky J;Scott DW;Keegan AD
通讯作者：
Keegan AD
影响因子：
7.3
作者：
Adi, Sabag D.;Eiza, Nasren;Vadasz, Zahava
通讯作者：
Vadasz, Zahava