登革病毒非結構蛋白一對玻尿酸的調控及作用

Effects of dengue virus nonstructural protein 1 on the modulation and function of hyaluronan

林俊祐(Chun-Yu Lin)

指導教授 ： 陳彥旭

高雄醫學大學/醫學院/醫學研究所博士班/博士(2020年)

摘要

嚴重登革熱主要的病理特徵為血管內皮細胞屏障功能缺損，這同時也是其他許多病毒出血熱的特徵。已知玻尿酸及其接受器CD44的訊息傳導異常與血管內皮細胞之功能異常有關；另一方面，登革病毒非結構蛋白一（nonstructural protein 1，NS1）和登革病毒造成的血管滲漏有關，然而，其所牽涉的分子機轉仍未知。藉由分析登革熱病人檢體資料庫，我們發現登革熱病程早期過量製造的玻尿酸，是登革熱病人出現警示徵象及嚴重登革熱的獨立預測因子。在實驗室中，以登革病毒NS1蛋白治療皮膚纖維母細胞及血管內皮細胞，會引發玻尿酸的過度製造，但對於玻尿酸裂解及CD44的影響則隨著細胞不同而異。玻尿酸及CD44的交互作用會影響內皮細胞的分化，並進一步惡化NS1蛋白引發的內皮細胞滲漏。有趣的是，玻尿酸異常增加的胞外基質，會吸引表現CD44的發炎細胞。我們也釐清了部分與製造玻尿酸訊息傳遞有關的訊息傳導途徑。結論來說，高血清玻尿酸濃度值是出現警示徵象與嚴重登革熱的生物標記；針對玻尿酸生合成及CD44接受器的藥理調控，可能可以改善發炎或感染時的血管內皮細胞滲漏現象。

關鍵字

CD44 ； 登革 ； 玻尿酸 ； 血管滲漏 ； VE-cadherin ； 細胞激素 ； 第二型玻尿酸合成酶 ； 第二型玻尿酸裂解酶 ； 乙型轉化生長因子

並列摘要

Background: A main pathological feature of severe dengue virus infection is endothelial hyper-permeability. The dengue virus nonstructural protein 1 (NS1) has been implicated in the vascular leakage that characterizes severe dengue virus infection, however, the molecular mechanisms involved are not known.

Methods: A cohort of 250 dengue patients has been followed from the onset of symptoms to the recovery phase. Serum hyaluronan levels and several other clinical parameters were recorded. The effect of NS1 treatment of cultured fibroblasts and endothelial cells on the expressions of hyaluronan synthetic and catabolic enzymes and the hyaluronan receptor CD44, were determined, as well as the formation of hyaluronan-rich matrices and endothelial permeability.

Findings: Elevated serum hyaluronan levels (≥70 ng/ml) during early infection was found to be an independent predictor for occurrence of warning signs, and thus severe dengue fever. High circulating levels of the viral protein NS1, indicative of disease severity, correlated with high concentration of serum hyaluronan. NS1 exposure decreased the expression of CD44 in differentiating endothelial cells impairing the integrity of vessel-like structures, and promoted the synthesis of hyaluronan in dermal fibroblasts and endothelial cells in synergy with dengue-induced pro-inflammatory mediators. Deposited hyaluronan-rich matrices around cells cultured in vitro recruited CD44-expressing macrophage-like cells, suggesting a mechanism for enhancement of inflammation. In cultured endothelial cells, perturbed hyaluronan-CD44 interactions enhanced endothelial permeability through modulation of VE-cadherin and cytoskeleton re-organization, and exacerbated the NS1-induced disruption of endothelial integrity.

Interpretation: Pharmacological targeting of hyaluronan biosynthesis and/or its CD44-mediated signaling may limit the life-threatening vascular leakiness during moderate-to-severe dengue virus infection.

並列關鍵字

CD44 ； Dengue ； Hyaluronan ； Vascular leakage ； VE-cadherin ； Cytokines ； HAS2 ； HYAL2 ； TGFbeta

參考文獻

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