ASN's Mission

To create a world without kidney diseases, the ASN Alliance for Kidney Health elevates care by educating and informing, driving breakthroughs and innovation, and advocating for policies that create transformative changes in kidney medicine throughout the world.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

Abstract: PO0631

The Transcription Factor GATA3 Regulates Hyaluronan-Mediated Stromal-Cell Responses During Kidney Injury, Repair, and Fibrosis

Session Information

Category: Development, Stem Cells, and Regenerative Medicine

  • 500 Development, Stem Cells, and Regenerative Medicine

Authors

  • Grigorieva, Irina, Cardiff University, Cardiff, South Glamorgan, United Kingdom
  • Buckby, Sarah, Cardiff University, Cardiff, South Glamorgan, United Kingdom
  • Brown, Charlotte Victoria Maynard, Cardiff University, Cardiff, South Glamorgan, United Kingdom
  • Steadman, Robert, Cardiff University, Cardiff, South Glamorgan, United Kingdom
  • Meran, Soma, Cardiff University, Cardiff, South Glamorgan, United Kingdom
Background

Stromal-mediated processes are critical in determining fibrosis progression. Stromal cells are essential for kidney development and homeostasis, but are also myofibroblast precursors and their maladaptive responses tip the balance from tissue repair to scarring. Our work shows that GATA3 is crucial for developing and mature renal stroma and its expression marks a distinct fibroblast subset associated with improved tissue outcomes following injury. Hyaluronan-(HA), a matrix glycosaminoglycan, is a key regulator fibroblast heterogeneity and predominance of distinct HA synthase (HAS) isoform expression separates fibroblasts into subsets which mediate fibrosis progression or resolution. Here, we investigated GATA3+ fibroblasts in relation to factors that regulate HA-matrix synthesis and metabolism during fibrosis progression versus prevention.

Methods

Immunohistology was performed on rat kidneys with bilateral ischaemia-reperfusion-injury +/- ischemic pre-conditioning (IPC) or BMP7 administration (prevention models). Primary human fibroblasts were used to test the role of GATA3 in BMP7 antagonism of TGFβ1-driven myofibroblast differentiation. siRNA and plasmids were used for knockdown or over-expression. HA levels were correlated with fibrosis profiles using ELISA, RT-qPCR and immunofluorescence.

Results

GATA3+ fibroblasts increased in abundance during regenerative phase following injury, co-stained for PDGFRβ and surrounded repairing tubules. More GATA3+PDGFRβ+ fibroblasts were observed in prevention models suggesting a protective, anti-fibrotic role. In prevention models, prominent co-localisation was observed between GATA3 and HAS1 in VSMCs, distal tubules and a distinct stromal population. In contrast, GATA3 expression was attenuated in α-SMA+ myofibroblasts in chronic fibrotic lesions where HAS2 was prominent. In vitro, BMP7 induced GATA3 expression and GATA3 knockdown attenuated BMP7-driven antagonism of TGFβ1-driven myofibroblast differentiation, in part by increasing HAS2 expression and pericellular HA. HAS2 promoter analysis confirmed enrichment of GATA binding motifs.

Conclusion

GATA3 is critical for maintaining a distinct stromal subset and mediating the reno-protective effects of IPC and BMP7 on IRI-induced renal damage by modulation of HA-matrix and HAS isoform expression.