Differential effects of integrin‐linked kinase inhibitor Cpd22 on severe pulmonary hypertension in male and female rats

Abstract

Pulmonary arterial hypertension (PAH) is a progressive fatal disease with no cure. Inhibition of integrin-linked kinase (ILK) reverses experimental pulmonary hypertension (PH) in male mice, but its effect on severe experimental PH in either male or female animals is unknown. We examined effects of ILK inhibitor Cpd22 on rats with SU5416/hypoxia-induced PH; treatment was performed at six to eight weeks after PH initiation. Five weeks after PH initiation, male and female rats developed similar levels of PH. Eight weeks after PH induction, vehicle-treated male rats had more severe PH than females. Cpd22-treated males, but not females, showed complete suppression of phospho-Akt in small pulmonary arteries (PAs), significantly lower PA medial thickness and percentage of fully occluded arteries, decreased systolic right ventricle (RV) pressure, PA pressure, RV hypertrophy, RV end-diastolic pressure, and improved RV contractility index compared to vehicle-treated group. Cpd22 suppressed proliferation of human male and female PAH pulmonary artery vascular smooth muscle cell (PAVSMC). 17β-estradiol had no effect as a single agent but significantly attenuated Cpd22-dependent inhibition of proliferation in female, but not male, PAH PAVSMC. Taken together, these data demonstrate that male rats develop more severe PH than females but respond better to Cpd22 treatment by reducing pulmonary vascular remodeling, PH, and RV hypertrophy and improving RV functional outcomes. 17β-estradiol diminishes anti-proliferative effect of Cpd22 in female, but not male, human PAH PAVSMC. These findings suggest potential attractiveness of ILK inhibition to reduce established PH in males and suggest that the combination with estrogen-lowering drugs could be considered to maximize anti-proliferative and anti-remodeling effects of ILK inhibitors in females.

Current Understanding of the Right Ventricle Structure and Function in Pulmonary Arterial Hypertension

“…While PAH is more prevalent among females than males (Badesch et al, 2010), sex differences exist in the survival rates of PAH patients, with females demonstrating better outcomes (Jacobs et al, 2014;Lahm et al, 2014;Shen et al, 2020). The protective effects of the female sex hormone 17β-estradiol (estrogen; also known as E 2 ) has been investigated in animal models of PAH (Liu et al, 2014(Liu et al, , 2017bLahm et al, 2016).…”

“…Integrinlinked kinase (ILK) is an enzyme upregulated in PA vascular smooth muscle cells in PAH, resulting in PA remodeling and proliferation. ILK inhibition was shown to result in reduced PA and RV hypertrophy, decreased RV systolic and end-diastolic pressures, and improved contractility in male, but not female rats in a SuHx model (Shen et al, 2020). This was attributed to estrogen-mediated effects in females, as co-culture of human PA vascular smooth muscle cells with estrogen and ILK inhibitors, hindered the anti-proliferative effects of ILK inhibition (Shen et al, 2020).…”

TSC2-extracellular matrix crosstalk controls pulmonary vascular proliferation and pulmonary hypertension

“…Cell proliferation was examined using DNA synthesis analysis (bromodeoxyuridine (BrdU) incorporation assay) or Ki67 detection with specific antibody (Cell Signaling Technology, Danvers, MA) as described previously (7,8,48,49). For the BrdU incorporation assay, cells, serumdeprived for 48 hours, were incubated with 10μM BrdU (Abcam, Cambridge, MA) for 18 hours, fixed with 4% paraformaldehyde in PBS (Santa Cruz Biotechnology, Dallas, TX), permeabilized by 2M HCl, and stained with anti-BrdU antibody (BD Biosciences, San Jose, CA).…”

The Future Application of Organ-on-a-Chip Technologies as Proving Grounds for MicroBioRobots

“…MBRs, carrying pharmaceuticals expected to alter disease pathogenesis, would then be introduced to the system ( Figure 5 ). One candidate drug for the MBRs is Cpd22, a signaling inhibitor that has shown promise as a potential therapeutic for reducing vascular remodeling in existing PH experimental models [ 61 ]. As this inhibitor has only been shown to have an effect on smooth muscle cells, the organ-on-a-chip’s ECM would need to be penetrated.…”

“…This device is inspired by a previously published device used by Schuerle et al [ 45 ]. Next, a magnetically actuated microbiorobot carrying Cpd22, an inhibitor of SMC-driven remodeling [ 61 ], could be engineered to maneuver within an endothelialized lumen representing the vasculature. By employing a SMC-sensitive polymer cap [ 46 ], the robot would release the inhibitor upon contact with SMCs.…”