Macrophages Transfected with Adenovirus to Express IL-4 Reduce Inflammation in Experimental Glomerulonephritis

Abstract

Nephrotoxic nephritis (NTN) is characterized by acute macrophage-dependent inflammation and serves as a model of human glomerulonephritis. In this study we have transfected rat macrophages with recombinant adenovirus expressing IL-4 (Ad-IL4) and demonstrated that these transfected macrophages develop fixed properties as a result of transfection, as shown by reduced NO production in response to IFN-γ and TNF. Ad-IL4-transfected macrophages localized with enhanced efficiency to inflamed glomeruli after renal artery injection in rats with NTN compared with adenovirus expressing β-galactosidase (Ad-βgal)-transfected macrophages and produced elevated levels of the cytokine in glomeruli in vivo for up to 4 days. The delivery of IL-4-expressing macrophages produced a marked reduction in the severity of albuminuria (day 2 albuminuria, 61 ± 15 mg/24 h) compared with unmodified NTN (day 2 albuminuria, 286 ± 40 mg/24 h; p < 0.01), and this was matched by a reduction in the number of ED1-positive macrophages infiltrating the glomeruli. Interestingly, the injection of IL-4-expressing macrophages into single kidney produced a marked reduction in the numbers of ED1-positive macrophages in the contralateral noninjected kidney, an effect that could not be mimicked by systemic delivery of IL-4-expressing macrophages. This implies that the presence of IL-4-expressing macrophages in a single kidney can alter the systemic development of the inflammatory response. Macrophage transfection and delivery provide a valuable system to study and modulate inflammatory disease and highlight the feasibility of macrophage-based gene therapy.

Hydrodynamics-based delivery of the viral interleukin-10 gene suppresses experimental crescentic glomerulonephritis in Wistar–Kyoto rats

“…Macrophages transfected with adenovirus expressing IL-4 ex vivo reduced macrophage infiltration and albuminuria in an experimental model of GN. 31 However, this type of ex vivo gene transfer is both laborious and expensive because it requires the isolation, growth, and transduction of primary macrophages from each rat. Adenovirus vector, moreover, induces an immune response and causes side effects that render its repeated administration problematic.…”

Unique Expression of Suppressor of Cytokine Signaling 3 Is Essential for Classical Macrophage Activation in Rodents In Vitro and In Vivo

“…NTN is a robust model of macrophage-dependent injury in which there are reliable methods for quantifying infiltrating leukocytes and characterizing their phenotype (23,24). It was therefore ideal for analyzing SOCS protein expression in infiltrating macrophages.…”

“…We have previously shown that a high local concentration of IL-4 in the glomerulus, induced by IL-4 over-expressing macrophages, significantly reduced the severity of renal injury as assessed by glomerular macrophage number and albuminuria (24). Kidney sections from these experiments were re-analyzed to determine the total number glomerular macrophages and the number expressing SOCS1 and SOCS3.…”

“…1 wk later with rabbit nephrotoxic serum using our standard protocol (23). To establish high concentrations of IL-4 and IL-10 locally within the inflamed glomerulus, macrophages overexpressing these cytokines were injected directly into the renal artery (23,24) and severity of injury assessed as previously described (24).…”

Macrophage-Mediated Renal Injury Is Dependent on Signaling via the JNK Pathway

“…The transfer of NR8383 macrophages into normal rat glomeruli via renal artery perfusion induces a number of pro-inflammatory responses, which are not seen when the function of the transcription factor nuclear factor-B (NF-B) is inhibited in the transferred macrophages (10). In addition, the transfer of macrophages modified to secrete antiinflammatory cytokines (IL-1ra, IL-4, or IL-10) has been shown to suppress renal injury in animal models of anti-GBM disease (11)(12)(13). However, it is not clear whether this suppression of renal injury is due to modulation of macrophage function and/or effects of the secreted cytokines upon intrinsic renal cells and other leukocytes.…”