Tissue Barriers最新文献

Small extracellular vesicles (sEVs) are an important part of intercellular communication. They are phospholipid bilayer particles that carry active biomolecules such as proteins, various nucleic acids, and lipids. In recipient cells, sEVs can alter cellular functions, including cancer development and premetastatic niche formation in distant organs. Moreover, sEVs can carry cancer-specific features, which makes them promising biomarker candidates. However, the interactions of sEVs with biological barriers and consequences thereof, are not clarified yet. The blood-saliva barrier is crucial for preventing the entry of pathogens and (in)organic substances into the bloodstream, as well as molecule filtration from blood to saliva. The effects of brain derived DU145 prostate cancer (PCa) sEVs on a human submandibular salivary gland barrier (SSGB) in vitro were investigated. Small EVs were harvested from normoxic (N, atmospheric O₂) or hypoxic (H, 1% O₂) conditions, fluorescently labeled with CellTracker^TM Orange and thoroughly characterized. HTB-41 B2 cells were used as SSGB model cultured on 24-well ThinCert® inserts. After model optimization indicating effects of serum and serum-sEVs on barrier properties, PCa sEVs were applied to the basolateral (blood) side in either 10% serum, or serum-free conditions, and barrier integrity was continuously monitored for 40 hours. This study found that H and N PCa sEVs were uptaken by the SSGB in vitro model in similar quantities regardless of the media composition in the basolateral compartment. Permeation of fluorescent PCa sEVs into the apical compartment was not detectable with the applied methods. However, treatment with H and N sEVs under different serum conditions revealed distinct molecular clusters after hierarchical analysis of mRNA data measured by high-throughput qPCR, which were partly reflected at the protein level. For example, serum-reduction dependent decrease of barrier properties was accompanied with the decrease of CDH1 or Claudin-7 expression. Interestingly, the presence of H sEVs significantly increased the number of sEV-sized particles in the apical compartment of the SSGB model compared to basolaterally added N sEVs. This functional effect on the number of particles in the saliva (apical) compartment induced by different sEVs applied in the blood (basolateral) compartment might be a new approach to understand one possible mechanism how differences of salivary EVs might occur which then could be used as biomarker.

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.

Background: Gastric adenocarcinoma represents an aggressive type of cancer and an important cause of cancer mortality. Progress in gastric cancer therapeutics has resulted from a better understanding of the molecular pathogenesis of the disease and introduction of targeted therapies, but most gastric cancer patients still rely on non-targeted chemotherapy as the mainstay of treatment for advanced disease.

Methods: An analysis of publicly available series from The Cancer Genome Atlas (TCGA) gastric cancer cohort was undertaken to delineate the clinical and genomic landscape of gastric cancers with suppressed expression of claudin 18 compared with cancers with non-suppressed claudin 18. Claudin 18 suppressed cancers were defined as having an mRNA expression z-score relative to normal samples (log RNA Seq V2) of less than -1. Claudin 18 non-suppressed cancers were defined as having an mRNA expression z-score relative to normal samples (log RNA Seq V2) above 0.5.

Results: Gastric cancers with claudin 18 mRNA suppression represented 7.7% of the gastric adenocarcinomas of TCGA cohort, while non-suppressed cancers represented 46.6% of the cases. The two groups did not differ in clinical and genomic characteristics, such as mean age, histology, grade, and stage. The mutation landscape of claudin 18 suppressed cases included high mutation rates of TP53, of genes of the WNT/β-catenin pathway and of ubiquitin ligase FBXW7. Moreover, a subset of both claudin 18 suppressed and non-suppressed cancers displayed mutations in Mismatch Repair (MMR) associated genes or a high tumor mutation burden (TMB). At the mRNA expression level, claudin 18 suppressed gastric cancers showed up-regulation of EMT core transcription factor Snail 2 and down-regulation of genes of HLA cluster. The survival of gastric cancer patients with claudin 18 mRNA suppression was not significantly different compared with patients with non-suppressed claudin 18.

Conclusion: Sub-sets of gastric cancers with claudin 18 mRNA suppression displayed characteristics of potential therapeutic interest, such as mutations in WNT and PI3K pathways and MMR defects. These may guide the development of alternative targeted therapies, in this sub-set of gastric cancers which are not candidates for claudin 18 targeting therapies.

Celiac disease (CD) is characterized by the disruption of the intestinal barrier integrity and alterations in the microbiota composition. This study aimed to evaluate the changes in the fecal microbiota profile and mRNA expressions of intracellular junction-related genes in pediatric patients with CD compared to healthy controls (HCs). Thirty treated CD patients, 10 active CD, and 40 HCs were recruited. Peripheral blood (PB) and fecal samples were collected. Microbiota analysis was performed using quantitative real-time PCR (qPCR) test. The mRNA expressions of ZO-1, occludin, β-catenin, E-cadherin, and COX-2 were also evaluated. In active and treated CD patients, the PB expression levels of ZO-1 (p = 0.04 and 0.002, respectively) and β-catenin (p = 0.006 and 0.02, respectively) were lower than in HCs. PB Occludin's level was upregulated in both active and treated CD patients compared to HCs (p = 0.04 and 0.02, respectively). However, PB E-cadherin and COX-2 expression levels and fecal mRNA expressions of ZO-1, occludin, and COX-2 did not differ significantly between cases and HCs (P˃0.05). Active CD patients had a higher relative abundance of the Firmicutes (p = 0.04) and Actinobacteria (p = 0.03) phyla compared to treated subjects. The relative abundance of Veillonella (p = 0.04) and Staphylococcus (p = 0.01) genera was lower in active patients in comparison to HCs. Researchers should explore the precise impact of the gut microbiome on the molecules and mechanisms involved in intestinal damage of CD. Special attention should be given to Bifidobacteria and Enterobacteriaceae, as they have shown a significant correlation with the expression of tight junction-related genes.

Disruptions in polyamine metabolism have been identified as contributing factors to various central nervous system disorders. Our laboratory has previously highlighted the crucial role of polyamine oxidation in retinal disease models, specifically noting elevated levels of spermine oxidase (SMOX) in inner retinal neurons. Our prior research demonstrated that inhibiting SMOX with MDL 72527 protected against vascular injury and microglial activation induced by hyperoxia in the retina. However, the effects of SMOX inhibition on retinal neovascularization and vascular permeability, along with the underlying molecular mechanisms of vascular protection, remain incompletely understood. In this study, we utilized the oxygen-induced retinopathy (OIR) model to explore the impact of SMOX inhibition on retinal neovascularization, vascular permeability, and the molecular mechanisms underlying MDL 72527-mediated vasoprotection in the OIR retina. Our findings indicate that inhibiting SMOX with MDL 72527 mitigated vaso-obliteration and neovascularization in the OIR retina. Additionally, it reduced OIR-induced vascular permeability and Claudin-5 expression, suppressed acrolein-conjugated protein levels, and downregulated P38/ERK1/2/STAT3 signaling. Furthermore, our results revealed that treatment with BSA-Acrolein conjugates significantly decreased the viability of human retinal endothelial cells (HRECs) and activated P38 signaling. These observations contribute valuable insights into the potential therapeutic benefits of SMOX inhibition by MDL 72527 in ischemic retinopathy.

Blood barriers serve as key points of transport for essential molecules as well as lines of defense to protect against toxins. In vitro modeling of these barriers is common practice in the study of their physiology and related diseases. This review describes a common method of using an adaptable, low cost, semipermeable, suspended membrane to experimentally model three blood barriers in the human body: the blood-brain barrier (BBB), the gut-blood barrier (GBB), and the air-blood barrier (ABB). The GBB and ABB both protect from the outside environment, while the BBB protects the central nervous system from potential neurotoxic agents in the blood. These barriers share several commonalities, including the formation of tight junctions, polarized cellular monolayers, and circulatory system contact. Cell architectures used to mimic barrier anatomy as well as applications to study function, dysfunction, and response provide an overview of the versatility enabled by these cultural systems.

The maintenance of body homeostasis relies heavily on physiological barriers. Dysfunction of these barriers can lead to various pathological processes, including increased exposure to toxic materials and microorganisms. Various methods exist to investigate barrier function in vivo and in vitro. To investigate barrier function in a highly reproducible manner, ethically, and high throughput, researchers have turned to non-animal techniques and micro-scale technologies. In this comprehensive review, the authors summarize the current applications of organ-on-a-chip microfluidic devices in the study of physiological barriers. The review covers the blood-brain barrier, ocular barriers, dermal barrier, respiratory barriers, intestinal, hepatobiliary, and renal/bladder barriers under both healthy and pathological conditions. The article then briefly presents placental/vaginal, and tumour/multi-organ barriers in organ-on-a-chip devices. Finally, the review discusses Computational Fluid Dynamics in microfluidic systems that integrate biological barriers. This article provides a concise yet informative overview of the current state-of-the-art in barrier studies using microfluidic devices.

The development of novel strategies to counteract diseases related to barrier dysfunction is a priority, since sepsis and acute respiratory distress syndrome are still associated with high mortality rates. In the present study, we focus on the effects of the unfolded protein response suppressor (UPR) 4-Phenylbutyrate (4-PBA) in Lipopolysaccharides (LPS)-induced endothelial injury, to investigate the effects of that compound in the corresponding damage. 4-PBA suppressed binding immunoglobulin protein (BiP) - a UPR activation marker - and potentiated LPS - induced signal transducer and activator of transcription 3 (STAT3) and extracellular signal‑regulated protein kinase (ERK) 1/2 activation. In addition to those effects, 4-PBA enhanced paracellular hyperpermeability in inflamed bovine pulmonary endothelial cells, and did not affect cell viability in moderate concentrations. Our observations suggest that UPR suppression due to 4-PBA augments LPS-induced endothelial injury, as well as the corresponding barrier disruption.

Intestinal organoid technology has revolutionized our approach to in vitro cell culture due in part to their three-dimensional structures being more like the native tissue from which they were derived with respect to cellular composition and architecture. For this reason, organoids are becoming the new gold standard for undertaking intestinal epithelial cell research. Unfortunately, their otherwise advantageous three-dimensional geometry prevents easy access to the apical epithelium, which is a major limitation when studying interactions between dietary or microbial components and host tissues. To overcome this problem, we developed porcine colonoid-derived monolayers cultured on both permeable Transwell inserts and tissue culture treated polystyrene plates. We found that seeding density and culture format altered the expression of genes encoding markers of specific cell types (stem cells, colonocytes, goblets, and enteroendocrine cells), and barrier maturation (tight junctions). Additionally, we found that changes to the formulation of the culture medium altered the cellular composition of colonoids and of monolayers derived from them, resulting in cultures with an increasingly differentiated phenotype that was similar to that of their tissue of origin.