The P21-Activated Kinase 1 and 2 As Potential Therapeutic Targets for the Management of Cardiovascular Disease

Targeting P21-Activated Kinase 2 as a Novel Therapeutic Approach to Mitigate Endoplasmic Reticulum Stress in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is linked to prolonged endoplasmic reticulum (ER) stress. P21-activated kinase 2 (Pak2) facilitates a protective ER stress response. This study explores the mechanism and role of Pak2 in HFpEF pathology.

METHODS AND RESULTS

The HFpEF mouse model was established using a high-fat diet combined with the nitric oxide synthase inhibitor Nω-Nitro-l-arginine methyl ester (high-fat diet+Nω-Nitro-l-arginine methyl ester). The model exhibited the typical characteristics of HFpEF (cardiac hypertrophy, diastolic dysfunction with preserved systolic function, and lung edema) as determined by echocardiography and hemodynamic analysis. Terminal deoxynucleotidyl transferase dUTP nick end labeling and dihydroethidium staining results showed that cell death and reactive oxygen species generation were higher in the high-fat diet+Nω-Nitro-l-arginine methyl ester-treated group. Transmission electron microscopy revealed disruption of the ER subcellular structures in the HFpEF mouse model, while western blot analysis confirmed reduced Pak2 phosphorylation and impaired inositol-requiring enzyme 1/X-box binding protein 1 splicing ER stress response signaling. Furthermore, H9c2 cells subjected to the palmitic acid-mediated metabolic stress developed temporal changes in unfolded protein response proteins and Pak2 activity. The inositol requiring enzyme 1/X-box binding protein 1 splicing branch of unfolded protein response was impaired earlier than other branches. Overexpression of Pak2 by adenovirus in H9c2 cells sustained the activation of inositol requiring enzyme 1/X-box binding protein 1 splicing. Pak2 deficiency in the mouse heart accelerated the HFpEF progression, and this phenomenon occurred as early as 10 weeks in Pak2 cardiomyocyte-specific knockout mice. Conversely, adeno-associated virus serotype 9-mediated Pak2 overexpression mitigated HFpEF symptoms, underscoring its protective role against HFpEF progression.

CONCLUSIONS

Pak2 prevents HFpEF progression, exerting cardioprotective effects against ER stress. These insights underscore the therapeutic value of Pak2 in HFpEF.

Regulation of Vascular Injury and Repair by P21-Activated Kinase 1 and P21-Activated Kinase 2: Therapeutic Potential and Challenges

The PAK (p21-activated kinases) family is a class of intracellular signal transduction protein kinases that regulate various cellular functions, mainly through their interactions with small GTP enzymes. PAK1 and PAK2 in the PAK kinase family are key signal transduction molecules that play important roles in various biological processes, including morphological changes, migration, proliferation, and apoptosis, and are involved in the progression of many diseases. Abnormal expression or dysregulation of PAK1 and PAK2 may be associated with several diseases, including cancer, neurological diseases, etc. The current research mainly focuses on studying the role of PAK and PAK inhibitors in the regulation of cancer progression, but relatively few reports are available that explore their potential role in cardiovascular diseases. Vascular injury and repair are complex processes involved in many cardiovascular conditions, including atherosclerosis, restenosis, and hypertension. Emerging research suggests that PAK1 and PAK2 have pivotal roles in vascular endothelial cell functions, including migration, proliferation, and angiogenesis. These kinases also modulate vascular smooth muscle relaxation, vascular permeability, and structural alterations, which are critical in the development of atherosclerosis and vascular inflammation. By targeting these activities, PAK proteins are essential for both normal vascular physiology and the pathogenesis of vascular diseases, highlighting their potential as therapeutic targets for vascular health. This review focuses on recent studies that offer experimental insights into the mechanisms by which PAK1 and PAK2 regulate the biological processes of vascular injury and repair and the therapeutic potential of the current existing PAK inhibitors in vascular-related diseases. The limitations of treatment with some PAK inhibitors and the ways that future development can overcome these challenges are also discussed.