Dengue virus non-structural protein 1 (DENV-NS1) plays a key role in the vascular leakage associated with severe dengue; however, the molecular mechanisms by which NS1 induces endothelial dysfunction remain poorly understood. This study aimed to identify a new aspect of the pathogenic strategy: the post-transcriptional reprogramming of host endothelial cells via microRNAs (miRNAs) in NS1-induced DENV pathogenesis. Small RNA sequencing and subsequent bioinformatic analysis identified novel miRNA-gene regulatory networks responsive to DENV-NS1 in human brain microvascular endothelial cells. Multiple dysregulated novel miRNAs were identified as potential regulators of critical antiviral components (STAT1, SOCS1-6, OAS1), suggesting suppressed interferon signaling. Downregulation of identified novel miRNAs targeting IL-6, IL-10, IL-1α, IL-17A, CXCR4, and CXCR5 indicates increased pro-inflammatory cytokine production and chemokine-driven immune cell recruitment, thereby worsening endothelial inflammation and vascular leakage. The simultaneous targeting of cytoskeletal regulators (RAC1, ROCK1/2) and tight junction proteins (CLDN1, CLDN2, CLDN16, CLDN22) suggests a two-phase disruption of endothelial stability, characterized by cytoskeletal remodeling and compromised tight junction integrity as a bystander effect of DENV-NS1. The downregulation of several miRNAs targeting XIAP, MDM2/4, and SMAD family genes established the involvement of novel miRNAs in apoptosis regulation and TGF-β/SMAD-mediated endothelial cell signaling. Our findings suggest that DENV-NS1 alters endothelial miRNA networks, leading to reduced antiviral immunity, increased inflammation, and compromised vascular integrity. This study identifies novel miRNA-mediated regulatory nodes that could function as therapeutic targets to prevent or mitigate dengue-associated vascular leakage.
Wound healing is a dynamic and multifactorial process involving coordinated interactions among extracellular matrix (ECM) components, growth factors, proteolytic enzymes, and immune and stromal cells. An essential yet often underappreciated aspect of this process is restoration of the epithelial permeability barrier, which prevents fluid loss and microbial invasion following injury. Disruption of this coordination contributes to chronic, non-healing wounds such as diabetic ulcers and venous leg ulcers, which remain major clinical challenges. Recent advances identify cathepsins, particularly cathepsin D, as key proteases that extend beyond lysosomal degradation to regulate critical events in tissue repair. Cathepsin D modulates keratinocyte proliferation, fibroblast invasion, angiogenesis, and ECM remodeling, and supports re-epithelialization through processing of structural proteins such as transglutaminase 1. Emerging evidence indicates that cathepsin D indirectly influences junctional remodeling, including tight and adherens junction dynamics, thereby facilitating permeability barrier reformation during wound closure. Its activity is regulated by oxidative stress, advanced glycation end products, inflammatory mediators, and iron metabolism - factors highly relevant to chronic wound microenvironments. Beyond proteolysis, cathepsin D shapes fibroblast and macrophage phenotypes and processes vascular endothelial growth factor (VEGF), integrating metabolic and signaling pathways essential for tissue regeneration. Collectively, these findings position cathepsin D as a mechanistic regulator and promising therapeutic target in wound biology. This review synthesizes mechanistic insights linking cathepsin D-mediated proteolysis to epithelial junction reorganization and permeability barrier recovery, and highlights emerging therapeutic strategies for improving chronic wound healing.
The glomerular filtration barrier (GFB) is a size- and charge-selective filter regulating the passage of blood-borne solutes into the urinary space. However, solutes within the GFB may also originate from podocyte secretion, including extracellular matrix (ECM) components and signaling molecules. We developed a two-dimensional computational solute transport model incorporating two cross-sectional GFB geometries: one based on averaged rodent data and one reconstructed from a healthy adult human glomerular image. Four cases were examined, defined by the solute's source and its ability to pass the podocyte slit diaphragm. To account for a wide range of solute types, solute mobility, described by the effective diffusion coefficient (Deff), was varied over six orders of magnitude. For blood-borne solutes unable to pass the slit diaphragm, a steep concentration gradient forms, with the highest concentration adjacent to the podocytes. This gradient becomes steeper as Deff decreases, corresponding to larger or less mobile solutes. This finding has implications for barrier clogging and for mechanisms that may increase Deff, including the role of ECM fixed charge density or ECM turnover. For podocyte-synthesized solutes to move against filtrate flow, without being rapidly lost to the urinary space, the model suggests solutes must possess properties preventing passage through the slit diaphragm. This result provides context for the relatively large signaling molecule complexes and ECM components. Together, these findings suggest that the structural organization of the GFB, particularly the slit diaphragm, enables solute distribution and directional transport, and therefore provides insight into GFB maintenance and pathology.
The use of cannabinoid has been implicated in the treatment of various skin disorders with obscure mechanism of action. This study aimed to investigate the physiological roles of GPR55 in regenerating skin wounds and protecting keratinocyte apoptosis induced by UVB radiation. Here, we found that O1602, a GPR55 agonist, accelerated wound healing in keratinocyte-like HaCaT cells, and this effect was suppressed by pretreatment with inhibitors of protein kinase A (PKA), AMP-activated protein kinase (AMPK), sirtuin-1 (SIRT-1), and extracellular signal-regulated kinase (ERK). Although O1602 treatment promoted keratinocyte proliferation in HaCaT cell line but its proliferative effect did not contribute to enhancing wound healing. Indeed, O1602 upregulated expression of MMP-9, suggesting the stimulation of cell migration. O1602 treatment protected against UVB-induced keratinocyte apoptosis, and this effect was abolished by pretreatment with inhibitors belonging to the same class as that which suppressed the wound-healing response. Furthermore, western blotting analyses revealed that O1602 treatment induced AMPK phosphorylation, and this effect was inhibited by pretreatment of PKA inhibitor. Moreover, O1602 promoted ERK phosphorylation, and this effect was aborted by pretreatment of either AMPK inhibitor or SIRT-1 inhibitor. Enzymatic activation of SIRT-1 induced by O1602 was absent in AMPK inhibitor-pretreated HaCaT cells. Altogether, GPR55 mediates keratinocyte regeneration and exhibits its protective effect against UVB exposure via PKA/AMPK/SIRT-1/ERK-dependent mechanism.
