The double edge of anti-CD40 siRNA therapy: It increases renal microcapillar density but favours the generation of an inflammatory milieu in the kidneys of ApoE -/- mice

Miguel Hueso; Angela Casas; Adrian Mallén; Laura de Ramón; Nuria Bolaños; Cristian Varela; Josep M Cruzado; Joan Torras; Estanislao Navarro

doi:10.1186/s12950-019-0228-9

The double edge of anti-CD40 siRNA therapy: It increases renal microcapillar density but favours the generation of an inflammatory milieu in the kidneys of ApoE ^-/- mice

J Inflamm (Lond). 2019 Dec 16:16:25. doi: 10.1186/s12950-019-0228-9. eCollection 2019.

Authors

Miguel Hueso¹, Angela Casas¹, Adrian Mallén², Laura de Ramón², Nuria Bolaños², Cristian Varela², Josep M Cruzado¹, Joan Torras¹, Estanislao Navarro³

Affiliations

¹ 1Department of Nephrology, Hospital Universitari Bellvitge, and Bellvitge Research Institute (IDIBELL). L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
² 2Laboratori de Nefrología Experimental, Bellvitge Research Institute (IDIBELL). L'Hospitalet de Llobregat, Barcelona, Spain.
³ Independent Researcher, Barcelona, Spain.

Abstract

Background: Chronic kidney disease (CKD) is associated with endothelial dysfunctions thus prompting links between microcirculation (MC), inflammation and major cardiovascular risk factors.

Purpose of the study: We have previously reported that siRNA-silencing of CD40 (siCD40) reduced atherosclerosis (ATH) progression. Here, we have deepened on the effects of the siCD40 treatment by evaluating retrospectively, in stored kidneys from the siCD40 treated ApoE^-/- mice, the renal microcirculation (measured as the density of peritubular capillaries), macrophage infiltration and NF-κB activation.

Methods: Kidneys were isolated after 16 weeks of treatment with the anti-CD40 siRNA (siCD40), with a scrambled control siRNA (siSC) or with PBS (Veh. group). Renal endothelium, infiltrating macrophages and activated NF-κB in endothelium were identified by immunohistochemistry, while the density of stained peritubular capillaries was quantified by image analysis.

Results: ATH was associated with a reduction in renal MC, an effect reversed by the anti-CD40 siRNA treatment (3.8 ± 2.7% in siCD40; vs. 1.8 ± 0.1% in siSC; or 1.9 ± 1.6% in Veh.; p < 0.0001). Furthermore, siCD40 treatment reduced the number of infiltrating macrophages compared to the SC group (14.1 ± 5.9 cells/field in siCD40; vs. 37.1 ± 17.8 cells/field in siSC; and 1.3 ± 1.7 cells/field in Veh.; p = 0.001). NF-κB activation also peaked in the siSC group, showing lower levels in the siCD40 and Veh. groups (63 ± 60 positive cells/section in siCD40; vs. 152 ± 44 positive cells/section in siSC; or 26 ± 29 positive cells/section in veh.; p = 0.014). Lastly, serum creatinine was also increased in the siCD40 (3.4 ± 3.3 mg/dL) and siSC (4.6 ± 3.0 mg/dL) groups when compared with Veh. (1.1 ± 0.9 mg/dL, p = 0.1).

Conclusions: Anti-CD40 siRNA therapy significantly increased the density of peritubular capillaries and decreased renal inflammation in the ATH model. These data provide a physiological basis for the development of renal diseases in patients with ATH. Furthermore, our results also highligth renal off-target effects of the siRNA treatment which are discussed.

Keywords: Atherosclerosis; Inflammatory milieu; Innate immunity; Kidney; Macrophage infiltration; Off-target side effects; siRNA therapy.