Impact and mechanisms of drag-reducing polymers on shear stress regulation in pulmonary hypertension

Article type: Research Article

Authors: Wang, Yali^{a; *} | Ye, Qing^a | Cui, Yongqi^a | Wu, Yunjiang^b | Cao, Sipei^{c; d} | Hu, Feng^{e; *}

Affiliations: [a] Department of Respiratory Medicine, School of Medicine, Renji Hospital, Shanghai Jiaotong University, Shanghai, China | [b] Department of Thoracic Surgery, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China | [c] Department of Respiratory Medicine, The Third People’s Hospital of Hefei, Hefei, China | [d] Clinical Medical College, Yangzhou University, Yangzhou, China | [e] Department of Cardiology, School of Medicine, Renji Hospital, Shanghai Jiaotong University, Shanghai, China

Correspondence: [*] Corresponding authors: Yali Wang, Department of Respiratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China; E-mail: [email protected] and Feng Hu, Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pujian Road, Shanghai 200127, China; E-mail: [email protected].

Abstract: BACKGROUND:Pulmonary hypertension (PH) is a refractory disease characterized by elevated pulmonary artery pressure and resistance. Drag-reducing polymers (DRPs) are blood-soluble macromolecules that reduce vascular resistance by altering the blood dynamics and rheology. Our previous work indicated that polyethylene oxide (PEO) can significantly reduce the medial wall thickness and vascular resistance of the pulmonary arteries, but the specific mechanism is still unclear. METHODS:This study was designed to investigate the role and mechanism of PEO on intracellular calcium [Ca2 +] i and cytoskeletal proteins of endothelial cells (ECs) induced by low shear stress (LSS) in PH. Primary Pulmonary Artery Endothelial Cells (PAECs) were subjected to steady LSS (1 dyn/cm2) or physiological shear stress (SS) (10 dyn/cm2) for 20 h in a BioFlux 200 flow system. Calcium influx assays were conducted to evaluate the mechanisms of PEO on [Ca2 +] i. Subsequently, taking the key protein that induces cytoskeletal remodeling, the regulatory light chain (RLC) phosphorylation, as the breakthrough point, this study focused on the two key pathways of PEO that regulate phosphorylation of RLC: Myosin light chain kinase (MLCK) and Rho-associated kinase (ROCK) pathways. RESULTS:Our current research revealed that PEO at LSS (1 dyn/cm2) significantly suppressed LSS-induced [Ca2 +] i and the expression level of transient receptor potential channel 1(TRPC1). In addition, ECs convert LSS stimuli into the upregulation of cytoskeletal proteins, including filamentous actin (F-actin), MLCK, ROCK, p-RLC, and pp-RLC. Further experiments using pharmacological inhibitors demonstrated that PEO at the LSS downregulated cytoskeleton-related proteins mainly through the ROCK and MLCK pathways. CONCLUSIONS:This study considered intracellular calcium and cytoskeleton rearrangement as entry points to study the application of PEO in the biomedical field, which has important theoretical significance and practical application value for the treatment of PH.

Keywords: Pulmonary hypertension, drag-reducing polymers, shear stress, myosin light chain kinase, Rho-associated kinase

DOI: 10.3233/CH-242281

Journal: Clinical Hemorheology and Microcirculation, vol. 88, no. 2, pp. 247-261, 2024