Human anti-α3(IV)NC1 antibody drug conjugates target glomeruli to resolve nephritis

Abstract

Current therapies to limit kidney disease progression lack specificity and often have systemic toxicity. To approach this problem, we postulated that a human monoclonal antibody (F1.1), directed against the noncollagenous-1 domain (NC1) of α3(IV) collagen that localizes in glomeruli, could serve as a vehicle for targeted drug delivery. Given enhanced exposure of the NC1 domain of α3(IV) during glomerular diseases, with limited epitope expression in other organs, α3(IV)NC1 provides an ideal target for delivery of disease-modifying agents. As a potential disease-modifying agent, we initially took advantage of recent observations that PGE2 promoted recovery after established injury during the course of nephrotoxic nephritis. To address the general applicability of the approach, the efficacy of glomerular delivery of dexamethasone was also examined. To achieve glomerular targeted therapy, PGE2 and dexamethasone were coupled to F1.1. After confirmation of the composition and activity of the conjugates, both glomerular localization and the capacity of the conjugates to modify disease were evaluated. After injection into mice with established nephritis, resolution of disease was enhanced with both agents, with normalization of histology and improved blood urea nitrogen levels in conjugate-treated mice compared with untreated mice. The results provide a novel means of targeting glomeruli during nephritis, irrespective of cause, by providing efficient drug delivery, with the potential of limiting systemic effects.

The TNF-derived TIP peptide activates the epithelial sodium channel and ameliorates experimental nephrotoxic serum nephritis

“…29 Initially, we assessed whether TIP peptide treatment could blunt pathology and restore renal function during the course of acute nephritis in a murine NTN model and whether this was primarily mediated by renal or systemic activities of the TIP peptide. Our results indicate that, during the course of NTN, TIP peptide, given either systemically, or targeted to glomeruli by conjugation of the peptide with a human monoclonal antibody against the type IV collagen a3NC1 domain, [30][31][32][33] significantly reduced pathology, diminished leukocyte renal infiltration, and improved kidney function, without increasing mean arterial blood pressure. These protective activities were blunted on cotreating mice with the cyclooxygenase inhibitor indomethacin, indicating a role for prostaglandins in recovery.…”

“…High-dose NTS caused mortality in 100% of mice on day 6, whereas 80% of mice treated with the F1.1-TIP peptide complex survived (n ¼ 5) ( Figure 5c). NTS mice treated with unconjugated F1.1 had the same severity of nephritis as NTS mice, indicating that antibody alone was not responsible for the reduction in disease (data not shown and the paper by Kvirkvelia et al 33 ).…”

“…F1.1-TIP peptide conjugation F1.1 human monoclonal antibody, with specificity for Ea and Eb epitopes of a3(IV) collagen, was purified and employed as described. 33 F1.1-TIP peptide conjugates were prepared by a 2-step conjugation procedure, as described. 33 Precise composition of conjugates was determined by high-performance liquid chromatography, using size exclusion columns and by amino acid analysis to calculate the number of peptide molecules linked per Ab.…”

“…To investigate whether there were direct effects of TIP peptide in glomeruli during NTN, we employed a glomerular delivery strategy shown to be effective with other drugs. 33 TIP peptide was chemically linked to the human mAb, F1.1, directed against a3(IV) collagen. 30,31 The conjugate was administered to mice on day 2 and day 4 of NTN (10 mg/kg body weight).…”

“…Because we have previously shown that glomerulartargeted PGE 2 ameliorates nephritis, 32,33 we investigated a role for PGE 2 in TIP-peptide-mediated restoration. PGE 2 generation was measured in supernatants from hTNF-treated hGEC, in the presence or absence of TIP peptide.…”