Date of Award
Master of Science in Biomedical Sciences
Richard E. White, Ph.D., FAHA
Shu Zhu, MD, Ph.D.
Harold Komiskey, Ph.D.
Lori Redmond, Ph.D.
INTRODUCTION: The World Health Organization (WHO) indicates that deaths from noncommunicable diseases (NCDs) are projected to increase to approximately 52 million by the year 2030. Of these NCDs, cardiovascular diseases (CVDs) constitute the number one cause of death globally and are the major source of morbidity and mortality associated with diabetes mellitus (DM). CVD manifests early in individuals with DM by way of vascular dysfunction, characterized by depressed nitric oxide (NO) production. As such, interventions to mediate the comorbidities associated with DM are being investigated.
OBJECTIVES: The primary objective of this study was to investigate the mechanism of action for allicin, a naturally-occurring compound in dietary garlic, to increase nitric oxide (NO) production in type-I diabetic donor coronary artery endothelial cells (DHCAEC-I).
METHODS: Endogenous H2S production following healthy donor coronary artery endothelial cell (HCAEC) and DHCAEC-I treatment with allicin was measured by way of fluorescence microscopy using the cell-trappable fluorogenic probe SF7-AM. Similarly, DAF-FM DA was used to measure NO production in the presence of allicin with and without wortmannin, an inhibitor targeting PI3K. To confirm the findings of DAF-FM DA fluorescence microscopy, immunoblots targeting p-eNOSSer1177, eNOS, p-AktSer473, and Akt were employed.
RESULTS: Treatment of HCAEC and DHCAEC-I with allicin resulted in increases in H2S by 126% and 85%, respectively (p < 0.01). NO production following allicin treatment increased in DHCAEC-I by 66% (p < 0.0001), the effect of which was diminished by the use of wortmannin (p < 0.0001). eNOSSer1177 phosphorylation in DHCAEC-I increased 89% from baseline after treatment with allicin (p < 0.05), the effect of which was also reversed by the use of wortmannin (p < 0.01). Allicin had no statistically-significant effects on NO production or eNOSSer1177 phosphorylation in HCAEC, and had no statistically-significant effects on AktSer473 phosphorylation in HCAEC or DHCAEC-I.
CONCLUSION: These data strongly support the hypothesis that allicin-mediated NO production is dependent on PI3K in DHCAEC-I. Future experiments are needed to determine the specific involvement of H2S and the targeted proteins downstream of PI3K.
Vásquez, Hunter Alberto, "Allicin stimulates the phosphorylation of eNOSSer1177 via a PI3K-dependent mechanism in type-I diabetic donor coronary artery endothelial cells" (2021). PCOM Biomedical Studies Student Scholarship. 206.