SARS-CoVS蛋白功能性受体ACE2在人、兔角膜、结膜中的表达

Expression of SARS coronavirus S protein functional receptor ACE2 in human and rabbit cornea and conjunctiva

目的 SARS冠状病毒 (SARS CoV)的S蛋白介导了病毒与宿主细胞的结合 ,最近已鉴定出SARS CoVS蛋白的功能性受体是血管紧张素转化酶 2 (angiotensin convertingenzyme 2 ,ACE2 )。本研究检测了ACE2在人、兔眼结膜、角膜中的表达 ,由此来初步推断SARS CoV由眼部入侵的可能。方法 分别采取 :(1)成人眼球破裂伤摘除的眼角膜和结膜组织 ;(2 ) 4～ 6月中期引产胎儿的眼角膜、结膜、心、肺组织 ;(3)兔眼角膜、结膜、心、肺组织 ;(4 )培养的人结膜成纤维细胞和兔角膜上皮细胞。分别采用RT PCR和免疫组化方法检测各组织、细胞中ACE2的表达。取尸体解剖的成人心、肺组织作为对照。结果 RT PCR法在上述各种组织和细胞中均检测到ACE2的扩增条带 ,其中胎儿、成人和兔的角膜、结膜扩增条带较心、肺稍弱 ,兔各组织的扩增条带亮度与对应的人体组织的扩增条带亮度相近。ACE2免疫组化反应产物主要位于胞浆和胞膜 ,呈棕黄色或棕褐色。角膜和结膜的上皮细胞及角膜内皮细胞呈明显的阳性表达 ,角膜和结膜的成纤维细胞呈弱阳性表达 ,培养的人结膜成纤维细胞和兔角膜上皮细胞亦可见阳性表达。兔组织中的ACE2表达强度及组织定位与人相近。结论 本研究从mRNA和蛋白质水平证实了眼组织存在SARS冠状病毒S蛋白的功能性受体ACE2 ,由?

Objective The spike proteins of SARS-CoV assoc ia te with cellular receptors of sensitive cells to mediate infection of their tar get cells.Recently,a metallopeptidase named angiotensin-converting enzyme 2( ACE2)has been identified as the functional receptor for SARS-CoV.The present s tudy investigated the expression of ACE2 in human and rabbit cornea and conjunct iva in an attempt to provide evidence about the possible route of SARS-CoV entr y via eyes. Methods ACE2 expression in human and rabbit cornea and conjunctiva was detected by RT-PCR and immunohistochemistry. Results Positive expression of ACE2 was det ected in human and rabbit cornea and conjunctiva.Amplified strands of ACE2 were detected by RT-PCR in corneal and conjunctival tissues and cells.The amplifie d strands were weaker in fetal,adult and rabbit cornea and conjunctiva than in hearts and lungs.Luminosity of the amplif ied strands of various tissues in rabbits was similar to that of the correspondi ng human tissue s.The product of ACE2 immunohistochemical reaction was mainly in the cytoplasm and cytomembrane,looking dark brown.Expression of ACE2 was significantly posit ive in corneal and conjunctival epithelia and corneal endothelia,and weakly pos itive in corneal and conjunctival fibroblasts.Positive expression of ACE2 was also detected in cultured human conjunctival fibroblasts and rabbit corneal epithelia.The strength of ACE2 expression and histological a pposition in the rabbit tissues were similar to those in human tissues. Conclusion These results indicate that there exist SARS-CoV S protein functional receptor -A CE2 in human and rabbit cornea and conjunctiva.So it is possible for SARS-CoV to enter by the cornea and conjunctiva.It is also po ssible to use rabbits as an animal model in investigating the possible route of SARS-CoV transmission.