Borroni Ester, Borsotti Chiara, Cirsmaru Roberta A, Kalandadze Vakhtang, Famà Rosella, Merlin Simone, Brown Brian, Follenzi Antonia
Department of Health Sciences, University of Piemonte Orientale, 28100 Novara, Italy.
Icahn Genomics Institute, Icahn School of Medicine at Mount Sinai, New York 10029, NY, USA.
Mol Ther Nucleic Acids. 2024 Jan 17;35(1):102116. doi: 10.1016/j.omtn.2024.102116. eCollection 2024 Mar 12.
Liver sinusoidal endothelial cells (LSECs) are specialized endocytic cells that clear the body from blood-borne pathogens and waste macromolecules through scavenger receptors (SRs). Among the various SRs expressed by LSECs is stabilin-2 (STAB2), a class H SR that binds to several ligands, among which endogenous coagulation products. Given the well-established tolerogenic function of LSECs, we asked whether the STAB2 promoter (STAB2p) would enable us to achieve LSEC-specific lentiviral vector (LV)-mediated transgene expression, and whether the expression of this transgene would be maintained over the long term due to tolerance induction. Here, we show that STAB2p ensures LSEC-specific green fluorescent protein (GFP) expression by LV in the absence of a specific cytotoxic CD8 T cell immune response, even in the presence of GFP-specific CD8 T cells, confirming the robust tolerogenic function of LSECs. Finally, we show that our delivery system can partially and permanently restore FVIII activity in a mouse model of severe hemophilia A without the formation of anti-FVIII antibodies. Overall, our findings establish the suitability of STAB2p for long-term LSEC-restricted expression of therapeutic proteins, such as FVIII, or to achieve antigen-specific immune tolerance in auto-immune diseases.
肝窦内皮细胞（LSECs）是一种特殊的内吞细胞，可通过清道夫受体（SRs）清除血液传播的病原体和废弃大分子，从而净化机体。LSECs表达的多种SRs中包括稳定素-2（STAB2），它属于H类SR，可与多种配体结合，其中包括内源性凝血产物。鉴于LSECs具有公认的免疫耐受功能，我们探究了STAB2启动子（STAB2p）是否能使我们实现LSEC特异性慢病毒载体（LV）介导的转基因表达，以及由于诱导免疫耐受，该转基因的表达是否能长期维持。在此，我们表明，即使存在GFP特异性CD8 T细胞，在没有特异性细胞毒性CD8 T细胞免疫反应的情况下，STAB2p也能确保LV在LSECs中特异性表达绿色荧光蛋白（GFP），这证实了LSECs强大的免疫耐受功能。最后，我们表明，在严重A型血友病小鼠模型中，我们的递送系统可部分且永久地恢复FVIII活性，且不会形成抗FVIII抗体。总体而言，我们的研究结果证实了STAB2p适用于长期限制LSECs表达治疗性蛋白（如FVIII），或在自身免疫性疾病中实现抗原特异性免疫耐受。
