Namavari Abed, Chaudhary Shweta, Ozturk Okan, Chang Jin-Hong, Yco Lisette, Sonawane Snehal, Katam Neelima, Khanolkar Vishakha, Hallak Joelle, Sarkar Joy, Jain Sandeep
Corneal Neurobiology Laboratory, Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, College of Medicine, 60612, USA.
Invest Ophthalmol Vis Sci. 2012 Jul 9;53(8):4575-85. doi: 10.1167/iovs.12-9760.
We determined Semaphorin 7a (Sema7a) localization and abundance in naive corneas and in corneas after nerve-transecting lamellar flap surgery, and determined the effect of Sema7a supplementation on corneal nerve regeneration and inflammation.
Immunolocalization and Western blot analyses were performed to evaluate the abundance of Sema7a in naive corneas and corneas undergoing nerve regeneration after lamellar corneal surgery in thy1-YFP+ neurofluorescent mice. We used compartmental cultures of dissociated trigeminal ganglion cells to determine the effect of Sema7a exposure on neurite outgrowth in vitro. Finally, a Sema7a pellet was implanted under the corneal flap after lamellar transection surgery to determine the neuronal and inflammatory effects of Sema7a supplementation in vivo.
Sema7a was expressed in the corneal epithelium and stromal keratocytes, but was more abundant in the epithelium (74.3%) compared to the stroma (25.7%, P = 0.02). Sema7a expression was increased significantly in the cornea after lamellar corneal surgery and was localized to stromal cells near the regenerating nerve fronds. Exposure of trigeminal neurites to Sema7a (20 nM) in the side compartment increased neurite length significantly. The implanted Sema7a pellet increased significantly YFP+ inflammatory cell influx into the cornea as well as increased corneal nerve length.
Sema7a is expressed constitutively in the cornea, and potently stimulates nerve regeneration and inflammatory cell influx. Therefore, this immune semaphorin links nerve regeneration and inflammatory processes in the cornea.
我们确定了在未受损角膜以及神经切断性板层角膜瓣手术后角膜中信号素7a（Sema7a）的定位和丰度，并确定了补充Sema7a对角膜神经再生和炎症的影响。
进行免疫定位和蛋白质印迹分析，以评估在thy1-YFP+神经荧光小鼠的未受损角膜和板层角膜手术后进行神经再生的角膜中Sema7a的丰度。我们使用分离的三叉神经节细胞的分隔培养来确定体外暴露于Sema7a对神经突生长的影响。最后，在板层横断手术后将Sema7a微丸植入角膜瓣下，以确定体内补充Sema7a对神经元和炎症的影响。
Sema7a在角膜上皮和基质角膜细胞中表达，但与基质（25.7%，P = 0.02）相比，在上皮中更丰富（74.3%）。板层角膜手术后角膜中Sema7a表达显著增加，并定位于再生神经纤维附近的基质细胞。在侧室中将三叉神经突暴露于Sema7a（20 nM）可显著增加神经突长度。植入的Sema7a微丸显著增加了YFP+炎症细胞向角膜的流入以及增加了角膜神经长度。
Sema7a在角膜中组成性表达，并有力地刺激神经再生和炎症细胞流入。因此，这种免疫信号素将角膜中的神经再生和炎症过程联系起来。
