Journal article
Mice Harboring the Obesity-Associated SNP rs1420185 Exhibit Increased Body Weight and Reveal an IRX3 Neuronal Circuit Regulating Body Weight
Molecular metabolism (Germany), Vol.100, 102234
10/2025
DOI: 10.1016/j.molmet.2025.102234
PMCID: PMC12419104
PMID: 40835181
Abstract
The single nucleotide polymorphism (SNP) rs1421085 has one of the highest associated risks with obesity of any SNP in the human genome. Through the generation of a novel mouse model harboring rs1421085 (OA-SNPrs142/rs142), we examined the impact of this SNP on energy balance. Furthermore, we investigated the role of IRX3, a potential mediator of the metabolic effects of rs1420185, in multiple brain regions.
To explore the impact and mechanisms of rs1420185, we monitored body weight, food intake, energy expenditure, and other metabolic parameters of OA-SNPrs142/rs142 mice under metabolic conditions similar to human obesogenic conditions (thermoneutral housing and 45% high fat diet). We additionally leveraged this model to investigate the impact of rs1421085 on genes that have been suggested to mediate the effects of this SNP on obesity. Finally, we used Irx3-Cre mice in combination with Cre-dependent AAV-Irx3 to determine if localized induction of IRX3 in neurons was sufficient to drive the energetic effects of rs1421085.
OA-SNPrs142/rs142 mice are more susceptible to diet-induced obesity and have increased food intake and decreased energy expenditure under human obesogenic conditions. Additionally, OA-SNPrs142/rs142 mice have elevated Irx3 mRNA expression in the brain with prominent expression in metabolically relevant regions such as the posterior hypothalamus (PH) and dorsal vagal complex (DVC). Increased IRX3 in the PH, but not the DVC, resulted in increased body weight and food intake. Finally, we found that increased expression of IRX3, specifically in IRX3+ neurons, decreases excitability and activity of IRX3+ neurons in the PH but not the DVC. Interestingly, inhibition of IRX3+ PH neurons led to increased body weight and food intake.
These data demonstrate that OA-SNPrs142/rs142 mice recapitulate the body weight phenotype associated with rs1421085 in humans and that increased IRX3 in the posterior hypothalamus, as seen in OA-SNPrs142/rs142 mice, is sufficient to drive some of the metabolic effects of the SNP.
•Mice harboring the obesity-associated SNP, rs1421085, phenocopy human body weight phenotypes.•Obesity-associated SNP mice (OA-SNPrs142/rs142) have elevated Irx3 expression in the CNS.•IRX3+ neurons are located primarily in the posterior hypothalamus and the dorsal vagal complex.•Increased expression of IRX3 in the posterior hypothalamus, but not the DVC, alters body weight.
Details
- Title: Subtitle
- Mice Harboring the Obesity-Associated SNP rs1420185 Exhibit Increased Body Weight and Reveal an IRX3 Neuronal Circuit Regulating Body Weight
- Creators
- Andrew I. Sullivan - University of IowaKyle H. Flippo - University of IowaIltan Aklan - University of OklahomaKristin E. Claflin - University of IowaDonald A. Morgan - University of IowaMeghan C. Naber - University of IowaKamal Rahmouni - University of IowaMatthew J. Potthoff - Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Resource Type
- Journal article
- Publication Details
- Molecular metabolism (Germany), Vol.100, 102234
- DOI
- 10.1016/j.molmet.2025.102234
- PMID
- 40835181
- PMCID
- PMC12419104
- NLM abbreviation
- Mol Metab
- ISSN
- 2212-8778
- eISSN
- 2212-8778
- Publisher
- Elsevier GmbH
- Grant note
- National Institutes of Health (NIH): R01DK106104, R01AG083950, F31DK137587 Veterans Affairs Merit Review Program: I01BX004634 National Institutes of Health: R01 HL162773, R01 HL172944 US Department of Veterans Affairs: I01BX004249, IK6BX006040
This work was funded by the National Institutes of Health (NIH) R01DK106104 (M.J.P.) , R01AG083950 (M.J.P.) , F31DK137587 (A.I. S.) , and the Veterans Affairs Merit Review Program I01BX004634 (M. J.P.) . K.R. is supported by the National Institutes of Health (R01 HL162773 and R01 HL172944) and US Department of Veterans Affairs (I01BX004249 and IK6BX006040) . The authors would like to acknowledge the University of Iowa Central Microscopy Research Facility, the University of Iowa Metabolic Phenotyping Core, and Dr. William Paradee at the University of Iowa Genome Editing Facility.
- Language
- English
- Electronic publication date
- 08/2025
- Date published
- 10/2025
- Academic Unit
- Iowa Neuroscience Institute; Fraternal Order of Eagles Diabetes Research Center; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984948137902771
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