Background: Salivary gland (SG) hypofunction is a characteristic feature of the autoimmune condition Sjögren’s Disease (SjD). SG hypofunction leads to xerostomia, a common disorder that severely hampers patient quality of life. Artificial saliva and many pharmacological approaches have been used, but do not restore salivary gland function. Salivary gland stem/progenitor cells (SGPCs) are normally responsible for the maintenance of SG function through their proliferation and differentiation into saliva producing acinar cells, are prematurely aged in SjD. Therefore, a promising regenerative strategy is the generation of pluripotent-stem cell (PSC)-derived SGPCs, for transplantation into SjD patients.

Objectives: This project aimed to develop a differentiation protocol that can yield transplantable SGPCs using embryonic stem cells (hES cells) as a starting point.

Methods: Standard hES cell lines were differentiated using combinations of small molecule pharmacological drugs and recombinant proteins to trigger signaling cascades present in the developing salivary gland during organogenesis. The differentiating cells were then characterized at the transcriptional level at various stages of maturation.

Results: A sequential downregulation of pluripotent, endoderm, and mesoderm markers, coupled with the prominent upregulation of non-neural ectoderm markers was observed, which characterizes committment of cells to the correct germ layer.By day 17 of differentiation, gene expression of non-neuronal/oral ectoderm markers was ~1000-fold higher than that of neural ectoderm, confirming committment to the ectoderm sublineage. To test if our day 17 cultures contained populations of SGPCs, we employed compared these to our standardized adult-stem cell donor-derived SG organoids (SGOs). In comparison to SGOs derived from healthy adult paroid, those from hES-‘SGPCs’ were similar but did not contain mature acinar cells, when exposed to our acinar-cell differentiation assay. In order to dissect the cell types present at the day 17 time point, we performed bulk RNASeq analysis. Day 17 differentiated cells, undifferentiated hES cells and SGO controls separated clearly from each other in PCA analysis. Heatmap analysis suggests that our cells at day 17 of differentiation may resemble earlier populations of basal epithelial progenitors, striated duct cells and SGPCs, based on marker genes reported in a recent study.

Conclusion: We have developed an hES differentiation protocol capable of yielding a heterogenous population of cells, likely containing various epithelial progenitor cell types. For the development of an hES-SGPC therapy for hyposalivation in SjD, we plan to utilise this knowledge to isolate the most potent SGPCs from our cultures.

REFERENCES: NIL.

Acknowledgements: This project was funded by ReumaNL and the Dutch Cancer Foundation KWF.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.