# Renal macrophage TLR7 signaling in lupus nephritis: from pathogenic mechanisms to therapeutic opportunities

## TL;DR

This review discusses how TLR7 signaling in kidney macrophages contributes to lupus nephritis and explores potential therapeutic strategies.

## Contribution

The paper highlights TLR7's role in macrophages as a novel therapeutic target for lupus nephritis.

## Key findings

- TLR7 activation in macrophages drives inflammation and tissue damage in lupus nephritis.
- Single-strand RNA triggers TLR7 signaling, creating a self-reinforcing feedback loop in the kidney.
- Modulating TLR7 signaling offers potential for new treatments in lupus nephritis.

## Abstract

Recent studies, including reports of rare monogenic Toll-Like Receptor 7 (TLR7) gain-of-function mutations, have established TLR7 as a causal driver in a subset of human systemic lupus erythematosus (SLE) cases. Consequently, TLR7 and its downstream mediators have emerged as promising therapeutic targets. Beyond its role in B cells, TLR7 is also critical within the renal tissue of patients with lupus nephritis (LN), where single strand RNA (ssRNA) drives aberrant TLR7 activation in macrophages. This activation promotes robust inflammatory cytokines production, exacerbating autoantigen generation and inflammatory tissue damage in a self-reinforcing feedback loop that accelerates LN progression. This review explores the role of TLR7 in LN pathogenesis through the lens of macrophage biology, with the goal of identifying novel therapeutic strategies that modulate the TLR7 signaling pathway.