Key Lab of Transplant Engineering and Immunology, MOH; Regenerative Medical Research Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
Apoptosis. 2020 Feb;25(1-2):105-119. doi: 10.1007/s10495-019-01583-3.
Liver fibrosis usually progresses to liver cirrhosis and even hepatocellular carcinoma. Since activated hepatic stellate cells (aHSCs) are responsible for liver fibrosis, reducing the quantity of aHSCs was considered the essential strategy for clinical antihepatofibrotic therapy. Due to the overexpression of TRAIL receptor 2 (DR5) in aHSCs, human TNF-related apoptosis-inducing ligand (hTRAIL) that could induce aHSCs apoptosis might be feasible for antihepatofibrotic therapy. However, the in vivo aHSCs-apoptosis-induction of hTRAIL is limited by its poor cell-targeting and a short half-life. In this study, we found that platelet-derived growth factor receptor β (PDGFRβ) was co-expressed with DR5 in aHSCs. And the Z affibody with high affinity for PDGFRβ could bind aHSCs and, thus, accumulate in the fibrotic liver. Z was fused to hTRAIL to produce the fusion protein Z-hTRAIL. Compared to hTRAIL, Z-hTRAIL showed greater in vitro cell binding and apoptosis-induction in aHSCs. In addition, Z-hTRAIL induced apoptosis of aHSCs but spared other normal liver cells. In vivo, Z-hTRAIL accumulated preferentially in fibrotic livers and exerted greater effects than hTRAIL in inducing aHSCs apoptosis and reducing extracellular matrix (ECM) deposition. These results demonstrated that the antihepatofibrotic effect of hTRAIL was improved by PDGFRβ-targeted delivery. To enhance its pharmacokinetics, Z-hTRAIL was modified with 10 kDa polyethylene glycol (PEG), which significantly (30-40 times) prolonged its half-life. The PEGylated long-acting Z-hTRAIL was more potent than the native Z-hTRAIL in regressing liver fibrosis. These results suggest that the aHSC-targeting and long-acting Z-hTRAIL might serve as a novel tool for antihepatofibrotic therapy.
肝纤维化通常会进展为肝硬化，甚至肝癌。由于活化的肝星状细胞（aHSCs）是肝纤维化的主要原因，因此减少 aHSCs 的数量被认为是临床抗肝纤维化治疗的关键策略。由于 TRAIL 受体 2（DR5）在 aHSCs 中过度表达，因此能够诱导 aHSCs 凋亡的人 TNF 相关凋亡诱导配体（hTRAIL）可能适用于抗肝纤维化治疗。然而，hTRAIL 在体内诱导 aHSCs 凋亡的效率受到其较差的细胞靶向性和半衰期短的限制。在本研究中，我们发现血小板衍生生长因子受体 β（PDGFRβ）与 DR5 在 aHSCs 中共表达。并且对 PDGFRβ 具有高亲和力的 Z 亲和体可以与 aHSCs 结合，从而在纤维化的肝脏中积累。Z 与 hTRAIL 融合产生融合蛋白 Z-hTRAIL。与 hTRAIL 相比，Z-hTRAIL 在体外显示出更强的 aHSCs 细胞结合和凋亡诱导作用。此外，Z-hTRAIL 诱导 aHSCs 凋亡，但不影响其他正常的肝细胞。在体内，Z-hTRAIL 优先在纤维化肝脏中积累，并在诱导 aHSCs 凋亡和减少细胞外基质（ECM）沉积方面比 hTRAIL 发挥更大的作用。这些结果表明，通过 PDGFRβ 靶向递送，提高了 hTRAIL 的抗肝纤维化作用。为了增强其药代动力学性质，用 10 kDa 的聚乙二醇（PEG）对 Z-hTRAIL 进行修饰，使其半衰期显著延长（30-40 倍）。PEG 化长效 Z-hTRAIL 在逆转肝纤维化方面比天然 Z-hTRAIL 更有效。这些结果表明，aHSC 靶向和长效 Z-hTRAIL 可能成为抗肝纤维化治疗的新工具。
