Abstract
摘要:嗜中性白血球數量豐富並且具有防禦感染的功能。然而癌症以及多種發炎反應異常疾病包括嚴重慢性阻塞性肺病、類風溼性關節炎以及病毒疱疹性結膜炎等,都與組織內累積過多嗜中性白血球數目有關。針對該細胞趨化與移行所發展出的治療性單株抗體或是趨化阻斷劑等,均具有臨床治療的潛力。 過去我們利用表現第 15號細胞激素 (IL-15)異構體 (ASIL-15)的 ENU突變鼠發現,該小鼠經過刮擦刺激後不論皮層細胞增生與破壞程度、調控嗜中性白血球移行的G-CSF和CXCL1生成以及皮膚內嗜中性白血球浸潤數目均顯著地比野生型正常鼠為低。因此,我們推論 ASIL-15應具有抗發炎反應的作用。 皮層細胞產生 IL-15。雖然 IL-15在血中濃度低,但是在牛皮癬病人的組織內的 IL-15卻有增加,顯示它在局部組織有作用。本研究將利用兩種方式將 ASIL-15直接表現在正常小鼠的皮層細胞。研究目的一:首先利用基因槍將表現 ASIL-15的質體送進皮層細胞並且檢測該蛋白表現。研究目的二:利用刮擦刺激或是簡單型疱疹病毒感染表現 ASIL-15的皮膚,分析檢測 ASIL-15對於皮層細胞的增生與活化以及嗜中性白血球浸潤皮膚組織的影響。研究目的三,建立特定表現在皮層細胞的 ASIL-15基因轉殖鼠,以進一步探討 ASIL-15調控皮膚發炎反應的分子機制。提供未來對於研究皮膚發炎性相關疾病新的動物模式與新藥發展。
Abstract: Neutrophils are the most abundant immune cells in the body. Effector functions of neutrophils are essential in the control of invading microbial pathogens but meanwhile could also be detrimental in tissue damages if not resolved properly. Excessive accumulation of neutrophils in tissues has been implicated in cancers and the pathogenesis of many human inflammatory diseases such as severe chronic obstructive pulmonary disease, rheumatoid arthritis and herpetic keratitis. Several therapeutic interventions using monoclonal antibody to neutralize chemoattactant or non-peptide chemokine receptor antagonists in targeting neutrophil mobilization pathway have been developed for clinical investigations. In our previous study, we have observed alleviated neutrophil infiltration in abraded, inflamed skin of the chemical N-ethyl-N-nitrosourea (ENU) mutagenized B6 mice which bore a point mutation in IL-15 gene and predominantly expressed an alternatively spliced isoform (ASIL-15). While stimulation of the epidermis by abrasion caused keratinocyte damages and subsequently induced proliferation and activation of keratinocyte in B6 skin, production of cytokine (G-CSF) and chemokine (CXCL1) involved in neutrophil granulocytogenesis and recruitment was transient and declined rapidly in IL-15 mutant skin. The results have led us to hypothesize that the particular IL-15 isoform could have anti-inflammatory effects through the regulation of keratinocyte homeostasis in skin. The primary source of IL-15 in skin is keratinocytes. Increased expression of IL-15 is found in skin lesions of patients with psoriasis which is a common skin inflammatory disease in human. Since IL-15 is usually detected at very low level in serum, the biological effect mediated by IL-15 is presumed to take place locally. To demonstrate the modulatory function of ASIL-15 in skin as observed in our previous experiments, in this study, we will propose to trans-express ASIL-15 in the epidermis rather than given systemically. The goals of this study will be achieved by two approaches. For a proof-of-concept demonstration, in Aim 1, we will express an ASIL-15 plasmid vector in the epidermis of mouse skin by gene gun technology followed by the investigations on the effects of ASIL-15 on neutrophil recruitment to inflamed skin induced by abrasion or via herpes simplex virus-1 infection as proposed in Aim 2. Lastly in Aim 3, we will establish the transgenic mice which will specifically express ASIL-15 in the epidermis under tissue specific K14 promoter control. The transgenic mouse model will be useful to investigate the molecular mechanisms by which ASIL-15 regulates the homeostasis of keratinocytes and the subsequent outcomes on neutrophil recruitment to skin. The mouse model is also potentially useful for investigations on other skin related inflammatory disorders including psoriasis and allergic skin inflammation. Results from proposed study will demonstrate ASIL-15 a potential therapeutic mediator which blocks the early events in initiating cutaneous inflammation.
Keyword(s)
嗜中性白血球
基因槍技術
基因轉殖鼠
免疫療法
皮膚發炎反應
neutrophils
IL-15
gene gun technology
transgenic mice
immunotherapy
skin inflammation