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Inhibition of HIV replication through siRNA carried by CXCR4-targeted chimeric nanobody


Small interfering RNA (siRNA) application in therapy still faces a major challenge with the lack of an efficient and specific delivery system. Current vehicles are often responsible for poor efficacy, safety concerns, and burden costs of siRNA-based therapeutics. Here, we describe a novel strategy for targeted delivery of siRNA molecules to inhibit human immunodeficiency virus (HIV) infection. Specific membrane translocation of siRNA inhibitor was addressed by an engineered nanobody targeting the HIV co-receptor CXCR4 (NbCXCR4) in fusion with a single-chain variable fragment (4M5.3) that carried the FITC-conjugated siRNA. 4M5.3–NbCXCR4 conjugate (4M5.3X4) efficiently targeted CXCR4+ T lymphocytes, specifically translocating siRNA by receptor-mediated endocytosis. Targeted delivery of siRNA directed to the mRNA of HIV transactivator tat silenced Tat-driven viral transcription and inhibited the replication of distinct virus clades. In summary, we have shown that the engineered nanobody chimera developed in this study constitutes an efficient and specific delivery method of siRNAs through CXCR4 receptor.

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This work was supported by the HIVERA—Harmonizing, Integrating and Vitalizing European Research on AIDS/HIV [Grant number HIVERA/0002/2013], and the Fundação para a Ciência e a Tecnologia—Ministério da Educação e Ciência (FCT-MEC), Portugal [Grant numbers UTAP-ICDT/DTP-FTO/0016/2014, VIH/SAU/0013/2011, VIH/SAU/0020/2011, VIH/SAU/0029/2011, PTDC/SAU-EPI/122400/2010]. CC-S acknowledges FCT-MEC for PhD fellowship SFRH/BD/73838/2010. PRLP acknowledges FCT-MEC for PhD fellowship SFRH/BD/81941/2011. FM acknowledges FCT-MEC for PhD fellowship SFRH/BD/87488/2012.

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CC-S, NT, and JG conceived and designed the experiments. CC-S, PRLP, FM, JGO, MC, and AM performed the experiments and analyzed the data. CC-S drafted the manuscript. All authors read and approved the final manuscript.

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Correspondence to Joao Goncalves.

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Cunha-Santos, C., Perdigao, P.R.L., Martin, F. et al. Inhibition of HIV replication through siRNA carried by CXCR4-targeted chimeric nanobody. Cell. Mol. Life Sci. 77, 2859–2870 (2020).

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  • Small interfering RNA
  • CXCR4
  • Nanobody
  • Delivery
  • HIV