Targeting Rho kinase to restore endothelial barrier function following vascular scaffold implantation

FLRT3 Overexpression Attenuates Ischemia-Reperfusion Induced Vascular Hyperpermeability and Lung Injury Through RND3

PURPOSE

Pulmonary ischemia/reperfusion injury (IRI) causes endothelial barrier dysfunction and increased vascular permeability. Fibronectin leucine-rich transmembrane protein-3 (FLRT3) is known to regulate endothelial cell function, but its role in pulmonary IRI remains unexplored.

METHODS

We established both a mouse lung I/R model and a hypoxia/reoxygenation (H/R) cell culture model using human pulmonary microvascular endothelial cells (HPMECs). The effects of FLRT3 manipulation were assessed through lentiviral-mediated overexpression and knockdown approaches. Lung injury was evaluated by histological analysis, immunohistochemistry, and lung injury scoring. Endothelial barrier function was assessed using transmission electron microscopy, Evans blue extravasation, and endothelial permeability assays.

RESULTS

FLRT3 expression was predominantly localized in pulmonary endothelial cells and was downregulated following I/R injury. Lentiviral vectors overexpressing FLRT3 (LV-FLRT3, 1 × 109 TU/ml) via tail vein injection before I/R surgery. FLRT3 overexpression effectively protected against lung injury by maintaining vascular integrity and reducing edema formation in I/R-challenged mice. In H/R-treated HPMECs, we identified that FLRT3 protein underwent autophagic-lysosomal degradation. Mechanistically, FLRT3 preserved endothelial barrier function through interaction with Rho family GTPase 3 (RND3), which prevented RhoA pathway-mediated cytoskeletal disruption. FLRT3 overexpression in HPMECs promoted cell migration, maintained cytoskeletal structure, and reduced endothelial hyperpermeability under H/R conditions. Importantly, RND3 knockdown in vivo significantly attenuated FLRT3's protective effects against I/R injury, as evidenced by increased lung injury scores, vascular permeability, and RhoA pathway activation.

CONCLUSIONS

Our findings reveal FLRT3, a critical regulator of endothelial barrier function during IRI through the RND3-RhoA pathway, is a potential therapeutic target for pulmonary IRI.

Kurarinone regulates Th17/Treg balance and ameliorates autoimmune uveitis via Rac1 inhibition

INTRODUCTION

Autoimmune uveitis (AU) is a severe intraocular autoimmune disorder with a chronic disease course and a high rate of blindness. Kurarinone (KU), a major component of the traditional Chinese medicine Sophorae Flavescentis Radix, possesses a wide spectrum of activities and has been used to treat several inflammation-related diseases.

OBJECTIVE

We aimed to investigate the effects of KU on AU and its modulatory mechanisms.

METHODS

We used an experimental autoimmune uveitis (EAU) animal model and characterized the comprehensive immune landscape of KU-treated EAU mice using single-cell RNA sequencing (scRNA-seq). The retina and lymph nodes were analyzed. The siRNAs and selective inhibitors were used to study the signaling pathway. The effect of KU on peripheral blood mononuclear cells (PBMCs) from uveitis patients was also examined.

RESULTS

We found that KU relieved chorioretinal lesions and immune cell infiltration in EAU model mice. Subsequent single-cell analysis revealed that KU downregulated the EAU-upregulated expression of inflammatory and autoimmune-related genes and suppressed pathways associated with immune cell differentiation, activation, and migration in a cell-specific manner. KU was implicated in restoring T helper 17 (Th17)/regulatory T (Treg) cell balance by alleviating inflammatory injury and elevating the expression of modulatory mediators in Tregs, while simultaneously ameliorating excessive inflammation by Th17 cells. Furthermore, Rac1 and the Id2/Pim1 axis potentiated the pathogenicity of Th17 cells during EAU, which was inhibited by KU treatment, contributing to the amelioration of EAU-induced inflammation and treatment of AU. In addition, KU suppressed inflammatory cytokine production in activated human PBMCs by inhibiting Rac1. Integration of the glucocorticoid-treated transcriptome suggests that KU has immunomodulatory effects on lymphocytes.

CONCLUSION

Our study constructed a high-resolution atlas of the immunoregulatory effects of KU treatment on EAU and identified its potential therapeutic mechanisms, which hold great promise in treating autoimmune disorders.

Drug- and Cell-Type-Specific Effects of ROCK Inhibitors as a Potential Cause of Reticular Corneal Epithelial Edema

Rho-associated kinase (ROCK) inhibitors have gained popularity as novel treatment options in the management of glaucoma and corneal endothelial disorders. Among the various ocular side effects, reticular corneal epithelial edema has been most frequently reported, mainly after treatment with netarsudil. To explain the potential mechanisms, we comparatively analyzed the effects of ripasudil and netarsudil on corneal endothelial and epithelial function in vitro. Primary human corneal endothelial and epithelial cells were incubated with netarsudil dihydrochloride and ripasudil hydrochloride dihydrate for up to 7 days. Gene and protein expression analyses were performed by real-time PCR and immunocytochemistry. Functional assays assessed the cell migration, proliferation, viability, Na+/K+-ATPase activity, transcellular electrical resistance, and FITC-dextran permeability. Reticular bullous corneal epithelial edema was observed in a patient following netarsudil 0.02%/latanoprost 0.005% ophthalmic solution (Roclanda®) for elevated intraocular pressure. In the subsequent laboratory analyses, both netarsudil and ripasudil were found to improve the corneal endothelial pump and barrier function, but they showed differential effects on corneal epithelial cells. Whereas ripasudil improved the epithelial barrier function by upregulating major components of the tight and adherens junctions and reducing paracellular permeability, netarsudil had no or even adverse effects on the epithelial barrier properties by downregulating the expression levels of cell-junction-associated genes. The expression changes normalized after discontinuation of ROCK inhibitors. The findings support the concept that ROCK inhibitors can act as a double-edged sword by having beneficial effects on corneal endothelial cells and adverse effects on epithelial cells.

An overview of recent advancements in small molecules suppression of oncogenic signaling of K-RAS: an updated review

RAS (rat sarcoma) oncoproteins are crucial for the growth of some human cancers, including lung, colorectal, and pancreatic adenocarcinomas. The RAS family contains three known human isoforms H(Harvey)-RAS, N(Neuroblastoma)-RAS, and K(Kirsten)-RAS. Mutations in RAS proteins cause up to ~ 30% of cancer cases. For almost 30 years, mutant proteins druggable pockets remained undiscovered, they are nearly identical to their essential, wild-type counterparts and cause cancer. Recent research has increased our knowledge of RAS's structure, processing, and signaling pathways and revealed novel insights into how it works in cancer cells. We highlight several approaches that inhibit RAS activity with small compounds in this review: substances that blocked farnesyltransferase (FTase), isoprenylcysteine carboxyl methyltransferase (Icmt), and RAS-converting enzyme 1 (Rce1) three important enzymes required for RAS localization. Inhibitors block the son of sevenless (SOS) protein's role in nucleotide exchange activity, small molecules that interfered with the phosphodiesterase (PDEδ)-mediated intracellular RAS transport processes, substances that focused on inhibiting RAS-effector interactions. Inhibitors are made to suppress the oncogenic K-RAS G12C mutant only when the nucleophilic cysteine residue at codon 12 is present and many inhibitors with various mechanisms like breaking the organization membrane of K-RAS nano-clustering. So, this is a thorough analysis of the most recent advancements in K-RAS-targeted anticancer techniques, hopefully offering insight into the field's future.