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Updated: May 25, 2026
Generation of a Mouse Spontaneous Autoimmune Thyroiditis Model
Published on: March 17, 2023
Mice deficient in dual oxidase maturation factors are severely hypothyroid
Helmut Grasberger1, Xavier De Deken, Olga Barca Mayo
1Biomedical Science Research Building, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA. hgrasber@gmail.com
Abstract:
Dual oxidases (DUOX1 and DUOX2) are evolutionary conserved reduced nicotinamide adenine dinucleotide phosphate oxidases responsible for regulated hydrogen peroxide (H(2)O(2)) release of epithelial cells. Specific maturation factors (DUOXA1 and DUOXA2) are required for targeting of functional DUOX enzymes to the cell surface. Mutations in the single-copy Duox and Duoxa genes of invertebrates cause developmental defects with reduced survival, whereas knockdown in later life impairs intestinal epithelial immune homeostasis. In humans, mutations in both DUOX2 and DUOXA2 can cause congenital hypothyroidism with partial iodide organification defects compatible with a role of DUOX2-generated H(2)O(2) in driving thyroid peroxidase activity. The DUOX1/DUOXA1 system may account for residual iodide organification in patients with loss of DUOX2, but its physiological function is less clear. To provide a murine model recapitulating complete DUOX deficiency, we simultaneously targeted both Duoxa genes by homologous recombination. Knockout of Duoxa genes (Duoxa(-/-) mice) led to a maturation defect of DUOX proteins lacking Golgi processing of N-glycans and to loss of H(2)O(2) release from thyroid tissue. Postnatally, Duoxa(-/-) mice developed severe goitreous congenital hypothyroidism with undetectable serum T4 and maximally disinhibited TSH levels. Heterozygous mice had normal thyroid function parameters. (125)I uptake and discharge studies and probing of iodinated TG epitopes corroborated the iodide organification defect in Duoxa(-/-) mice. Duoxa(-/-) mice on continuous T4 replacement from P6 showed normal growth without an overt phenotype. Our results confirm in vivo the requirement of DUOXA for functional expression of DUOX-based reduced nicotinamide adenine dinucleotide phosphate oxidases and the role of DUOX isoenzymes as sole source of hormonogenic H(2)O(2).
Insights
Dual oxidases (DUOX) and their maturation factors (DUOXA) are essential for hydrogen peroxide production in epithelial cells. Complete DUOXA deficiency in mice causes congenital hypothyroidism, confirming DUOX enzymes
Area of Science:
- Biochemistry
- Cell Biology
- Endocrinology
Background:
- Dual oxidases (DUOX) and their maturation factors (DUOXA) are crucial for producing hydrogen peroxide (H2O2) in epithelial cells.
- Mutations in DUOX2 and DUOXA2 are linked to congenital hypothyroidism in humans, highlighting DUOX2's role in thyroid hormone synthesis.
- The physiological role of the DUOX1/DUOXA1 system remains less understood, necessitating further investigation.
Purpose of the Study:
- To create a murine model of complete DUOX deficiency by targeting both Duoxa genes.
- To investigate the in vivo function of DUOXA proteins in DUOX enzyme maturation and H2O2 production.
- To elucidate the role of DUOX isoenzymes in thyroid hormone synthesis and overall physiological function.
Main Methods:
- Simultaneous knockout of both Duoxa genes in mice using homologous recombination to generate Duoxa(-/-) mice.
- Assessment of DUOX protein maturation, N-glycan processing, and H2O2 release in thyroid tissue.
- Evaluation of thyroid function in Duoxa(-/-) mice, including serum T4 and TSH levels, (125)I uptake and discharge, and iodinated thyroglobulin epitopes.
Main Results:
- Duoxa(-/-) mice exhibited impaired DUOX protein maturation, lacking Golgi processing of N-glycans, and a complete loss of H2O2 release from thyroid tissue.
- Duoxa(-/-) mice developed severe goitrous congenital hypothyroidism with undetectable serum T4 and elevated TSH levels, confirming a significant iodide organification defect.
- Continuous T4 replacement therapy from postnatal day 6 allowed Duoxa(-/-) mice to grow normally without an overt phenotype, indicating thyroid hormone's critical role.
Conclusions:
- DUOXA is essential for the functional expression of DUOX enzymes, acting as a critical maturation factor.
- DUOX isoenzymes are the primary source of hormonogenic H2O2 required for thyroid hormone synthesis.
- The Duoxa(-/-) mouse model provides a valuable tool for studying DUOX-related disorders and thyroid hormone regulation.
