# Biological functions of Interleukin - 26

> **NIH NIH R21** · UNIVERSITY OF WASHINGTON · 2022 · $221,360

## Abstract

Project Summary/Abstract:
In this proposal, we will define the functions of an understudied cytokine interleukin-26 (IL-26) at the mucosal
barrier using human and zebrafish models. Cytokines have pleiotropic functions for both the adaptive and
innate arms of the immune system to promote antimicrobial immunity, regulate inflammation, and maintain
tissue homeostasis. IL-26, produced by Th17 cells, is associated with inflammatory diseases in humans, such
as rheumatoid arthritis, ulcerative colitis, and psoriasis. The underlying role of IL-26 in these inflammatory
diseases is not well understood. Since mice do not encode the IL26 gene, studies that address the biology of
IL-26 have been lacking. Our understanding of IL-26 biology is primarily restricted to the effect IL-26 has on
epithelial cells, due to apparent tissue and cellular restriction of the IL-26 receptor. Moreover, as IL-26 is
absent in mice and other rodents, it has posed a significant barrier in understanding its biological functions. As
such, studies of IL-26 biology have been limited to in vitro cell culture models. However, we have identified a
homolog of human IL-26 in zebrafish that is characterized by a highly conserved IL-10 family signature motif
and has similar synteny as in humans. There is extensive sequence and functional conservation between
human and zebrafish genomes, including genes involved in innate and adaptive immunity. To this end, we will
(i) define the transcription and signaling networks induced by IL-26 in human keratinocytes and (ii) define the
role of IL-26 in antimicrobial responses at mucosal surfaces in zebrafish. The proposed experiments will
provide unprecedented insight into the biological function of IL-26 in inflammation and antimicrobial immunity,
with important implications for the role of IL-26 in initiation and progression of inflammatory disease.

## Key facts

- **NIH application ID:** 10428646
- **Project number:** 5R21AI156000-02
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** John D Hansen
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $221,360
- **Award type:** 5
- **Project period:** 2021-06-14 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10428646

## Citation

> US National Institutes of Health, RePORTER application 10428646, Biological functions of Interleukin - 26 (5R21AI156000-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10428646. Licensed CC0.

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