Genetic Deletion of LRP5 and LRP6 in Macrophages Exacerbates Colitis-Associated Systemic Inflammation and Kidney Injury in Response to Intestinal Commensal Microbiota.
Level 5 - mechanism / opinion, no new human data
Animal and cellular mechanistic research with no human data
PubMed 35760519 · doi:10.4049/jimmunol.2101172
What was done
Researchers evaluated the role of Wnt coreceptors LRP5 and LRP6 in macrophages during colitis-associated systemic complications. They generated mice with myeloid-specific conditional deletion of LRP5 and LRP6 (LRP5/6 LysM mice) and subjected them to dextran sodium sulfate (DSS)-induced colitis. They assessed systemic inflammation, acute kidney injury, bacterial translocation, the effect of gut microbiota depletion, and in vitro macrophage responses to Toll-like receptor ligands and downstream mitogen-activated protein kinase activation.
What was found
The abstract reports qualitative findings without numerical data or effect sizes. Conditional deletion of macrophage LRP5/6 in mice worsened susceptibility to DSS colitis-induced systemic inflammation and acute kidney injury. This exacerbation was linked to increased bacterial translocation to extraintestinal sites and microbiota-dependent elevations of renal proinflammatory cytokines; depleting gut microbiota mitigated these injuries. In vitro, LRP5/6-deficient macrophages showed hyperresponsiveness to Toll-like receptor ligands, produced higher levels of proinflammatory cytokines, and showed increased activation of mitogen-activated protein kinases.
Why it matters
These findings identify a gut-kidney crosstalk mechanism in inflammatory bowel disease models, suggesting that macrophage Wnt-LRP5/6 signaling acts as a protective regulator against microbiota-driven systemic inflammation and distant organ injury.
Limits
The study was conducted entirely in murine models and cellular assays, meaning findings may not translate directly to human disease. The abstract provides no quantitative data, sample sizes, effect magnitudes, or variance metrics.
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