Tissue Barriers最新文献

Claudin-18.2 is a promising therapeutic target for gastrointestinal cancer. However, its expression pattern in pancreatic ductal adenocarcinoma, especially the concordance between biopsy and resection specimens, is unknown. This study aimed to evaluate the consistency of claudin-18.2 positivity across different specimen types using the clinically validated antibody clone 43-14A employed in ongoing zolbetuximab trials. Immunohistochemical analysis for claudin-18 was conducted on 211 resected pancreatic cancer tissues, 133 matched preoperative biopsy samples, and 60 samples from recurrent lesions. The concordance between the biopsy and resection specimens was 92.5% using a 75% staining threshold. However, this high concordance likely reflects the large proportion of claudin-18.2-negative cases, as the biopsy sensitivity for detecting claudin-18.2-positive tumors was only 54.6%. This raises concerns about underdiagnosis and suggests that biopsy alone may miss patients eligible for zolbetuximab therapy. Receiver operating characteristic analysis showed that lowering the threshold to 20% in biopsy samples improved the sensitivity to 100%. However, patients meeting this threshold would still not qualify for therapy under the current trial criteria, highlighting a potential clinical dilemma. Claudin-18.2 expression was generally preserved in recurrent lesions (83.3% concordance with primary tumors), although reductions were noted in local recurrence and liver metastasis. These findings suggest that although biopsy-based assessments may be a practical initial tool, they should be interpreted with caution. Confirmatory studies on resection specimens using the same clinical trial protocol may be necessary to ensure the accurate identification of patients eligible for claudin-18.2-targeted therapy.

Exosomes^, (EXs) competence in reproductive medicine has been proven, particularly in cases of ischemia reperfusion (IR) injury models. Testicular torsion is a major clinical concern affecting male fertility and results in ischemic reperfusion injury. To the best of our knowledge, up to date, comparative studies using different routes of EXs application have not been investigated. Thus, we aimed to investigate the effect of local versus systemic EXs administration on both testes; ipsilaterally and contralaterally and to explore the involved underlying mechanisms. Rats were allocated into four groups; the control, the ischemia reperfusion group (IR group) in which unilateral testicular IR was performed, then rats were subdivided equally into two subgroups; IR-ipsi group; in which the ipsilateral testes were investigated and the IR-contra group in which the contralateral testes were examined. Group III and group IV in which unilateral IR was performed, then injected intravenously or intratesticularly consequently with EXs and finally divided in to two subgroups IR-ipsi and IR-contra. The results revealed that testicular IR resulted in functional and structural disorders with reduction in serum testosterone and sperm indices. Interestingly, both testes showed structural histopathological changes and defects in blood testis barrier. There was also an increase in oxidative stress, inflammatory, and apoptosis markers. EXs administration improved the affected parameters probably via modulation of TLR4/MyD88/NF-κB signaling pathway. In conclusion, EXs defended against testicular IR injury. Intratesticular administration had better effects on the ipsilateral testes, whereas Intravenous route had more obvious better effects on the contralateral ones.

Madecassoside, one of the main bioactive compounds found in Centella asiatica extract, has long been used in the cosmetic regime for skin care with doubtful effects. The main objectives of this study are to investigate the effects of Madecassoside on skin wound healing, UVB-induced keratinocyte damages, and to search for its pharmacological mechanism. Here, using fully differentiated keratinocyte-like HaCaT cell monolayers as an in vitro model, we found that Madecassoside enhanced wound healing and protected against UVB-induced keratinocyte apoptosis and reduction of cell viability. Indeed, these pharmacological effects of Madecassoside were completely abolished by pretreatment of an intracellular Ca²⁺ chelator (BAPTA), inhibitors of AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), and extracellular signal-regulated kinase (ERK). In addition, our Western blotting analyses strongly indicated that Madecassoside-induced ERK phosphorylation was suppressed by pretreatment of BAPTA, inhibitors of AMPK and mTOR signaling. Collectively, these data suggested that Madecassoside promotes wound healing and reduces keratinocyte apoptosis after being damaged by UVB radiation, at least in part, via Ca²⁺/AMPK- and mTOR-dependent ERK phosphorylation.

This review describes similarities between the biological actions of cell adhesion molecule antagonists and pan-growth factor receptor tyrosine kinase (GF-RTK) antagonists. In particular, the biological consequences of the interaction between the cell adhesion molecule, neural (N)-cadherin (CDH2) and the fibroblast GF-RTK (FGF-RTK) are discussed. Intercellular adhesion mediated by N-cadherin stimulates FGF-RTK activity triggering intracellular signaling pathways (e.g. PI3/Akt/mTOR pathway) that regulate various morphogenetic processes (e.g. apoptosis). Antagonists of either N-cadherin or GF-RTKs modulate these processes. N-cadherin antagonists can be regarded as a previously unappreciated class of FGF-RTK inhibitors. These antagonists, similar to GF-RTK antagonists should be capable of serving as therapeutics for treating a variety of fibrotic diseases and cancers.

Claudins are essential components of tight junctions, and their abnormal expression is linked to cancer development. Claudin-6 (CLDN6) and Claudin-9 (CLDN9) are claudins whose expression is suppressed post-development but reinduced in various malignancies. This review highlights the distinct yet complementary roles of CLDN6 and CLDN9 during epithelial-mesenchymal transition (EMT) and their contributions to cell migration and invasion in cancer. CLDN9 primarily enhances cell migration by inducing cytoskeletal rearrangement and activating pathways, including MAPK and Tyk2/STAT3. Moreover, CLDN9 overexpression is associated with pseudopodia formation, glycolytic remodeling, and immune evasion. Conversely, CLDN6 is more strongly linked to cell invasiveness and matrix degradation, primarily through the induction of MMPs via the EGFR/mTOR and PI3K/AKT pathways. CLDN6 also plays a role in stemness and therapy resistance in specific cancers. While CLDN6 and CLDN9 can function independently, their co-expression is connected with aggressive tumor behavior and poor prognosis, suggesting a synergistic process that promotes migration and invasion.

Diabetes mellitus is a systemic disease characterized by chronic hyperglycemia, persistent inflammation, and oxidative stress. While the vascular complications of diabetes are well-documented, their impact on lung barrier integrity remains underexplored. In this study, we investigated the molecular mechanisms by which advanced glycation end-products (AGE) compromise the integrity of lung endothelial and epithelial barriers. Using human lung microvascular endothelial cells and epithelial (A549) cells, we assessed the impact of AGE on the tight junction protein claudin-5, adherens junction protein VE-cadherin, and key signaling molecules including the receptor for AGE (RAGE), phosphorylated Akt, and p38 MAPK as well as a panel of pro-inflammatory cytokines. Our findings demonstrated that AGE exposure (50 μg/mL) significantly activated Akt and p38 MAPK, upregulated Claudin-5 and RAGE, and downregulated VE-cadherin, correlating with reduced transendothelial electrical resistance in vitro. Notably, we observed similar effects on lung epithelial cells. Moreover, AGE-treated conditioned media from THP-1 macrophages induced a pronounced increase in inflammatory cytokines, amplifying the disruption of lung barrier integrity. These findings reveal a potential mechanism linking diabetes-induced vascular dysfunction and immune activation to compromised lung barrier function, emphasizing the need for further research into diabetes-associated lung complications.

This comprehensive review delves into the pivotal role of intestinal epithelial cells in the context of various diseases. It provides an in-depth analysis of the diverse types and functions of these cells, explores the influence of multiple signaling pathways on their differentiation, and elucidates their critical roles in a spectrum of diseases. The significance of the gastrointestinal tract in maintaining overall health is extremely important and cannot be exaggerated. This complex and elongated organ acts as a crucial link between the internal and external environments, making it vulnerable to various harmful influences. Preserving the normal structure and function of the gut is essential for well-being. Intestinal epithelial cells serve as the primary defense mechanism within the gastrointestinal tract and play a crucial role in preventing harmful substances from infiltrating the body. As the main components of the digestive system, they not only participate in the absorption and secretion of nutrients and the maintenance of barrier function but also play a pivotal role in immune defense. Therefore, the health of intestinal epithelial cells is of vital importance for overall health.

Vascular endothelial barrier disruption is a critical determinant of morbidity and mortality in sepsis. Whole blood represents a key source of paracrine signaling molecules inducing vascular endothelial barrier disruption in sepsis. This study analyzes whole-genome transcriptome data from sepsis patients' whole blood available in the NCBI GEO database to identify paracrine mediators of vascular endothelial barrier dysfunction, uncovering novel insights that may guide drug repositioning strategies. This study identifies the regulated expression of paracrine signaling molecules TFPI, MMP9, PROS1, JAG1, S1PR1, and S1PR5 which either disrupt or protect vascular endothelial barrier function in sepsis and could serve as potential targets for repositioning existing drugs. Specifically, TFPI (barrier protective), MMP9 (barrier destructive), PROS1 (barrier protective), and JAG1 (barrier destructive) are upregulated, while S1PR1 (barrier protective) and S1PR5 (barrier protective) are downregulated. Our observations highlight the importance of considering both protective and disruptive mediators in the development of therapeutic strategies to restore endothelial barrier integrity in septic patients. Identifying TFPI, MMP9, PROS1, JAG1, S1PR1, and S1PR5 as druggable paracrine regulators of vascular endothelial barrier function in sepsis could pave the way for precision medicine approaches, enabling personalized treatments that target specific mediators of endothelial barrier disruption to improve patient outcomes in sepsis.

The ubiquitin-proteasome system (UPS) carries immense significance concerning cellular homeostasis that encompasses both ubiquitination and deubiquitination as key facets for maintaining protein stability. The deubiquitinating enzymes (DUBs) have emerged as critical regulators of proteostasis, neuroinflammation and blood-brain barrier (BBB) integrity by controlling the fate of crucial proteins associated with barrier architectures in CNS and neurodegenerative disorders (NDs) alike. However, a concrete understanding of their specific neurodevelopmental and neuroprotective functions is yet to be discerned. This article discusses the multifaceted roles of DUBs in the maintenance of BBB integrity, neuroprotection and various NDs and also underscores the therapeutic prospects targeting the same. While DUBs like USP7, USP9X, USP27X, UCHL1, etc. participate in neural stem cell maintenance and neurogenesis, including BBB function, USP13, USP14, USP25, BRCC3 and CYLD, among others, are associated with BBB dysfunction and NDs. The mechanistic underpinning concerning their hitherto unexplored mode of action, DUB-substrate interactions and specificity would facilitate developing the therapeutic agonists and small-molecule inhibitors to prevent or reverse neuroinflammation, BBB impairment and developmental disorders. Recent innovations concerning DUB-targeting chimaeras (DUBTACs) and proteolysis-targeting chimaeras (PROTACs) can be explored further for their plausible administration via nanoparticle-based delivery approaches to alleviate the progressive neurodegeneration.

Breakdown of blood-brain barrier (BBB) represents a key pathology in hyperglycemia-mediated cerebrovascular damage after an ischemic stroke. As changes in the level and nature of vasoactive agents released by endothelial cells (ECs) may contribute to BBB dysfunction, this study first explored the specific impact of hyperglycemia on EC characteristics and secretome. It then assessed whether secretome obtained from ECs subjected to normoglycaemia or hyperglycemia might regulate pericytic cytokine profile differently. Using a triple cell culture model of human BBB, composed of brain microvascular EC (BMEC), astrocytes and pericytes, this study showed that exposure to hyperglycemia (25 mM D-glucose) for 72 h impaired the BBB integrity and function as evidenced by decreases in transendothelial electrical resistance and increases in paracellular flux of sodium fluorescein. Dissolution of zonula occludens-1, a tight junction protein, and appearance of stress fibers appeared to play a key role in this pathology. Despite elevations in angiogenin, endothelin-1, interleukin-8 and basic fibroblast growth factor levels and a decrease in placental growth factor levels in BMEC subjected to hyperglycemia vs normoglycaemia (5.5 mM D-glucose), tubulogenic capacity of BMECs remained similar in both settings. Similarly, pericytes subjected to secretome obtained from hyperglycemic BMEC released higher quantities of macrophage migration inhibitory factor and serpin and lower quantities of monocyte chemoattractant protein-1, intercellular adhesion molecule, interleukin-6 and interleukin-8. Taken together these findings indicate the complexity of the mechanisms leading to BBB disruption in hyperglycemic settings and emphasize the importance of endothelial cell-pericyte axis in the development of novel therapeutic strategies.