# Altered behaviour and immune response in mice with NHLRC2 p.Asp148Tyr variant

## TL;DR

This study explores how a specific NHLRC2 gene variant causes neurodevelopmental and immune issues in mice, offering insights into a rare human disease called FINCA.

## Contribution

The study identifies Rho GTPase signaling as a key pathway affected by the NHLRC2 p.Asp148Tyr variant in both human and mouse models.

## Key findings

- Mice with the NHLRC2 p.Asp148Tyr variant show hyperactivity and reduced exploration in adolescence.
- The variant alters innate immune responses, particularly increasing interferon γ production.
- Rho GTPase signaling is disrupted in both human and mouse cells with the NHLRC2 variant.

## Abstract

Fibrosis, neurodegeneration and cerebral angiomatosis (FINCA) is a childhood-onset neurodevelopmental disorder with multi-organ manifestations, including recurrent infections. It is caused by variants in NHLRC2, initiating a cascade of unknown pathological events.

We investigated the FINCA disease-causing p.Asp148Tyr variant in NHLRC2 by analysing transcriptional changes in mouse embryonic stem cells (mESCs). We conducted behavioural and immunological phenotyping of FINCA mice compound heterozygous for the Nhlrc2 knockout allele and p.Asp148Tyr variant and explored their T cell populations and cytokine production in splenocytes. Additionally, we employed proximity-labelling mass spectrometry to identify changes in protein–protein interactions resulting from the p.Asp148Tyr variant in human embryonic kidney cells.

We discovered significant transcriptional changes in mESCs homozygous for the p.Asp148Tyr variant or Nhlrc2 knockout allele compared to wild-type cells, with genes involved in cell metabolism, adhesion, neurodevelopment and immune response. FINCA mice exhibited hyperactivity and decreased exploration of new object in adolescence, and an altered innate immune response, particularly in interferon γ production. By comparing p.Asp148Tyr-induced changes in gene expression in mouse cells and putative interaction partners in human cells, we identified Rho GTPase signalling as a common affected pathway.

Our study provides insights into the molecular pathways impacted by the p.Asp148Tyr NHLRC2. The FINCA mouse, which recapitulates several features of the human condition, particularly neurodevelopmental and immune response defects, serves as a tool for investigations on the role of environmental triggers in disease pathogenesis. Our results suggest that targeting immune pathways could offer a strategy for therapeutic intervention in FINCA disease.

•FINCA disease is characterized by fibrosis, neurodegeneration, recurrent infections and chronic hemolytic anemia.•Mice carrying NHLRC2 p.Asp148Tyr variant display attention deficit, hyperactivity and decreased exploration in adolescence.•FINCA mouse model exhibit altered innate immune response, particularly IFNγ induction.•Rho GTPase signalling is affected by p.Asp148Tyr in NHLRC2 in both human and mouse cell culture models.

FINCA disease is characterized by fibrosis, neurodegeneration, recurrent infections and chronic hemolytic anemia.

Mice carrying NHLRC2 p.Asp148Tyr variant display attention deficit, hyperactivity and decreased exploration in adolescence.

FINCA mouse model exhibit altered innate immune response, particularly IFNγ induction.

Rho GTPase signalling is affected by p.Asp148Tyr in NHLRC2 in both human and mouse cell culture models.