Title

Effects of lipoteichoic acid and lipopolysaccharide on SHED

Lead Author Affiliation

Biomedical Sciences, Thomas J. Long School of Pharmacy

Second Author Affiliation

Biomedical Sciences

Third Author Affiliation

Biomedical Sciences

Introduction/Context

Stem cells from human exfoliated deciduous teeth (SHED) are a readily accessible source of stem cells. SHED are exposed to pathogen associated molecular patterns (PAMPs), such as lipoteichoic acid (LTA) and lipopolysaccharide (LPS) during pulpal inflammation and subsequent tissue regeneration. However, little is known about effects of PAMPs on SHED. We examine effects of PAMPs on SHED viability and proliferation, we also report on SHED expression of Toll-like receptors (TLRs) and SHED growth factor secretion in response to LTA.

Method

Viability, proliferation, TLR expression, and growth factor modulation were determined by trypan blue exclusion, WST-1 assay, flow cytometry, and antibody array, respectively. Statistics: ANOVA and Dunnett’s post-hoc test, n≥3 for all samples except antibody array.

Results

There was no significant reduction in viability over 48hrs for SHED exposed to graded doses of either LTA or LPS. SHED displayed no mitogenic effect from either LTA or LPS 48hr exposure. However, SHED proliferation was significantly inhibited by increasing doses of LPS but not LTA over the 48hr period (p<0.05). Flow cytometric analysis demonstrated SHED expression of TLR2 and TLR4. Interestingly, LTA 100ng/ml did modulate growth factor related protein secretion. Only 5 proteins were increased greater than 10% relative to controls, vascular endothelial growth factor receptor 3 (10%), insulin-like growth factor-1 (12%), vascular endothelial growth factor D (13%), placenta growth factor (17%) and stem cell factor (SCF, 29%). The majority of proteins were downregulated. Notably, the most highly downregulated protein was c-Kit, SCF cognate receptor (93%).

Significance/Conclusions

In summary, there was no significant mitogenic response of SHED to LTA or LPS. Furthermore, we believe we are first to demonstrate TLR2 and TLR4 expression in SHED. We also identify a potential stem cell-specific regulatory response of SHED to LTA stimulation involving SCF and its soluble receptor.

Comments

We thank University of Pacific Arthur A. Dugoni School of Dentistry for support through an intramural pilot grant. This work was presented at the 2017 AADR Annual Meeting, March 22-25, 2017, San Francisco, CA.

Location

University of the Pacific, Dugoni Dental School, San Francisco, CA

Format

Poster

Poster Session

Faculty, Student, and Staff Presentations

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Effects of lipoteichoic acid and lipopolysaccharide on SHED

University of the Pacific, Dugoni Dental School, San Francisco, CA

Stem cells from human exfoliated deciduous teeth (SHED) are a readily accessible source of stem cells. SHED are exposed to pathogen associated molecular patterns (PAMPs), such as lipoteichoic acid (LTA) and lipopolysaccharide (LPS) during pulpal inflammation and subsequent tissue regeneration. However, little is known about effects of PAMPs on SHED. We examine effects of PAMPs on SHED viability and proliferation, we also report on SHED expression of Toll-like receptors (TLRs) and SHED growth factor secretion in response to LTA.