(548.15) Chloride Intracellular Channel Protein 1 (CLIC1) Inhibitor (IAA94) Decreases Contractile Force in Rat Uterine Arteries

Poster Board Number: E31

Stephanie Wilczynski (University of South Carolina School of Medicine, University of South Carolina), Olufunke Arishe (University of South Carolina School of Medicine, University of South Carolina), Fernanda Priviero (University of South Carolina, University of South Carolina), R. Webb (University of South Carolina School of Medicine, University of South Carolina)

Objective

The objective of this study was to determine the effects of the Chloride Intracellular Channel Protein 1 (CLIC1) inhibitor, IAA94, on uterine arteries in rats.

Hypothesis

This study tested the hypothesis that the inhibition of CLIC1 with IAA94 decreases contractility of the uterine artery.

Methods

Uterine arteries were harvested from 12-week-old female Wistar Rats. The arterial rings were mounted in a wire myograph and kept at 37ºC in Krebs solution, constantly aerated with a 95% O2 + 5% CO2 gas mix. Concentration-response curves to Phenylephrine (PE, -9M to -4.5M). After washout, the arterial rings were incubated with the CLIC1 inhibitor (IAA94, 50 µM) for 30 minutes and then, concentration-responses curves to PE were repeated. The curves were analyzed using nonlinear regression analysis and pEC50 and Emax were calculated with an Nf8 for both groups. Data was analyzed by GraphPad Prism 9.2.0., and is presented as Mean ± SEM (n=8).

Summary of Results

In the Wistar uterine arterial rings, the potency of PE was decreased in the presence of the CLIC1 inhibitor IAA94 (pEC50: 5.64 ± 0.28 vs. 6.59 ± 0.30 for IAA94 vs control, respectively; p lt;0.0001). Similarly, Emax to PE was decreased after incubation with IAA94 (105 ± 2% vs 128 ± 5%, for IAA94 vs control, respectively; p lt;0.001). These data show that the inhibition of CLIC1 plays a role in the contraction induced by PE. Further experiments are necessary to understand the mechanisms underlying this effect.

Conclusion

The addition of the CLIC1 inhibitor, IAA94, elicits a decreased contractile response to PE. CLIC1 has been identified to be dysregulated in certain cancer types and aging. There are numerous overlaps between cell senescence/cancer morphology and the pathophysiology of preeclampsia. These preliminary experiments shed light on the uterine artery’s reactivity to a CLIC1 inhibitor and would be an interesting topic to pursue in pregnant rats in both SHR and Wistar strains. With hypertensive patients, we see an increase in peripheral contractility and a decrease in responsiveness to vasodilators. CLIC1 could be a possible target in vasoconstrictive pathways, especially those that occur during pregnancy and in preeclamptic patients.



Figure 1- Uterine Artery Contraction to PE The arterial rings were contracted with serial dilutions of PE, beginning with -9M until -4.5M (A). The pEC50s were calculated and the difference between the contractile response in the control versus the IAA94 treatment has a p<0.0001 after a 2-tailed paired t-test; pEC50: control 6.59 ± 0.30 vs. IAA94 treated 5.64 ± 0.28 (B). The EMax was calculated to compare the control versus IAA94 treated; 128.47 ± 14.38 vs. 104.89 ± 5.55 with a p=0.0034(C). N=8.