Abstract
Purpose : Baicalein is a natural flavonoid derived from the dried roots of Scutellaria baicalensis Georgi. We have previously demonstrated that baicalein lowers intraocular pressure (IOP) by increasing trabecular meshwork (TM) outflow facility. In this study, we investigated the mechanistic effects underlying the baicalein-mediated increase in outflow facility.
Methods : Five independent strains of primary human TM (hTM) cells were used. The effects of baicalein on hTM cell volume regulation, cell contractility and cell migration were determined by electronic cell sorting, collagen gel assay and scratch assay, respectively. Measurements of phosphorylated myosin light chain (pMLC) were conducted by Western blot analysis. Differential protein expression profile after baicalein treatment for 3 hours was assessed using isobaric tag for relative and absolute quantitation (iTRAQ) based quantitative proteomics.
Results : Our results showed that baicalein (1-100 µM) had no effect on cell volume under iso-osmotic condition, but caused a concentration-dependent inhibition of regulatory volume decrease (RVD) by up to 70% under hypotonic condition. Similarly, baicalein exhibited a concentration-dependent hTM cell relaxation and retarded cell migration when compared to the vehicle control. At 100 µM, baicalein reduced MLC phosphorylation by 18±9% (n=4, p
Conclusions : These findings suggest that baicalein triggers cell relaxation via MLC phosphorylation along with inhibiting RVD and migratory behavior in hTM cells. The baicalein-mediated changes in protein expression support the notion of altered extracellular matrix homeostasis, potentially contributing to a reduction of outflow resistance and thereby IOP.
Methods : Five independent strains of primary human TM (hTM) cells were used. The effects of baicalein on hTM cell volume regulation, cell contractility and cell migration were determined by electronic cell sorting, collagen gel assay and scratch assay, respectively. Measurements of phosphorylated myosin light chain (pMLC) were conducted by Western blot analysis. Differential protein expression profile after baicalein treatment for 3 hours was assessed using isobaric tag for relative and absolute quantitation (iTRAQ) based quantitative proteomics.
Results : Our results showed that baicalein (1-100 µM) had no effect on cell volume under iso-osmotic condition, but caused a concentration-dependent inhibition of regulatory volume decrease (RVD) by up to 70% under hypotonic condition. Similarly, baicalein exhibited a concentration-dependent hTM cell relaxation and retarded cell migration when compared to the vehicle control. At 100 µM, baicalein reduced MLC phosphorylation by 18±9% (n=4, p
Conclusions : These findings suggest that baicalein triggers cell relaxation via MLC phosphorylation along with inhibiting RVD and migratory behavior in hTM cells. The baicalein-mediated changes in protein expression support the notion of altered extracellular matrix homeostasis, potentially contributing to a reduction of outflow resistance and thereby IOP.
| Original language | English |
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| Title of host publication | Investigative Ophthalmology & Visual Science |
| Pages | 449 |
| Volume | 63 |
| ISBN (Electronic) | 1552-5783 |
| Publication status | Published - Jun 2022 |
| Event | Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting 2022 - Denver, United States Duration: 1 May 2022 → 4 May 2022 |
Conference
| Conference | Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting 2022 |
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| Abbreviated title | ARVO 2022 |
| Country/Territory | United States |
| City | Denver |
| Period | 1/05/22 → 4/05/22 |