Intercellular Connections Research Articles

Mechanisms of pulmonary microvascular endothelial cells barrier dysfunction induced by LPS: The roles of ceramides and the Txnip/NLRP3 inflammasome.

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are characterized by pulmonary microvascular endothelial cells (PMVECs) barrier dysfunction and proinflammatory cytokine influx into lung tissue, resulting in pulmonary oedema. Ceramide overproduction is an important mediator of pulmonary hyperinflammation and pulmonary oedema in Acute lung injury (ALI). Ceramides induce NLRP3 inflammasome activation are essential for the hyperinflammatory response. However, the roles and specific mechanisms of ceramide-induced NLRP3 inflammasome activation, proinflammatory cytokine manufacturing and PMVECs barrier dysfunction in ALI are unclear. Herein, pretreatment with the acid sphingomyelinase (ASMase) inhibitor imipramine (but not a neutral sphingomyelinase (NSMase) inhibitor or de novo pathway inhibitor) significantly inhibited ceramide early production in rats with lipopolysaccharide (LPS)-induced ALI; Furthermore, the Txnip/NLRP3 inflammasome activation, proinflammatory cytokine release, increased PMVECs permeability and lung injury were significantly decreased. Verapamil, a Txnip inhibitor, substantially inhibited Txnip/NLRP3 inflammasome activation, proinflammatory cytokine release, increased PMVECs permeability and lung injury in rats with C8-ceramide-induced ALI. In vitro, short hairpin RNA-mediated Txnip silencing significantly inhibited C8-ceramide-induced Txnip/NLRP3 inflammasome activation in NR8383 alveolar macrophages (AMs) and early secretion of the proinflammatory cytokines IL-1β (4-12h) as well as IL-6 and TNF-α at subsequent times (later than 12h). However, C8-ceramide significantly increased the early secretion (within 8h) of the proinflammatory cytokines IL-1β, IL-6 and TNF-α in a co-culture model of NR8383 AMs and PMVECs, and Txnip silencing of NR8383 AMs inhibited the secretion of pro-inflammatory cytokines and reduced cytoskeletal rearrangements, intercellular connection breakage and hyperpermeability in PMVECs. Overall, our results suggest that in LPS-induced ALI, ceramide-mediated Txnip/NLRP3 inflammasome activation in NR8383 AMs leads to early IL-1β release, subsequently inducing PMVECs injury and release of the proinflammatory cytokines IL-6 and TNF-α, ultimately leading to PMVECs barrier dysfunction and ALI.

Overview of junctional complexes during mammalian early embryonic development.

Cell-cell junctions form strong intercellular connections and mediate communication between blastomeres during preimplantation embryonic development and thus are crucial for cell integrity, polarity, cell fate specification and morphogenesis. Together with cell adhesion molecules and cytoskeletal elements, intercellular junctions orchestrate mechanotransduction, morphokinetics and signaling networks during the development of early embryos. This review focuses on the structure, organization, function and expressional pattern of the cell-cell junction complexes during early embryonic development. Understanding the importance of dynamic junction formation and maturation processes will shed light on the molecular mechanism behind developmental abnormalities of early embryos during the preimplantation period.

Cytotoxic properties of fac-Re(CO)3 complexes with quinoline coligands: Insights on the mode of cell death and DNA fragmentation

Four tricarbonyl rhenium(I) complexes featuring quinoline ligands (1–4) were examined for their potential cytotoxicity properties against three malignant cell lines and one normal cell line of different origins. The most cytotoxic compound among the synthesized complexes was complex 2, which was formed when [ReBr(CO)3(N∧O)] (N∧O = quinoline-2-carboxaldehyde) (1) and para-amino phenol reacted. Its IC50 values are in the range of 26.05–30.33 μg/mL. Complex 4, decorated with benzimidazole moiety, has been demonstrated to be harmless to normal mice splenocytes. The cellular localization of 1–4 was investigated using fluorescence microscopy to provide insight into their biotargets, cellular localization, and modes of action. Among the evaluated malignant cell lines, complex 2 exhibited the highest levels of apoptotic and necrotic alterations in the MCF-7 cell line. Re(I) complexes appeared to gather inside intercellular connections and around cellular membranes, as seen in the fluorescence microscopy images. Along the cell membrane, the compounds accumulated as well, anticipating their entry.

3D reconstruction of the cerebellar germinal layer reveals tunneling connections between developing granule cells.

The difficulty of retrieving high-resolution, in vivo evidence of the proliferative and migratory processes occurring in neural germinal zones has limited our understanding of neurodevelopmental mechanisms. Here, we used a connectomic approach using a high-resolution, serial-sectioning scanning electron microscopy volume to investigate the laminar cytoarchitecture of the transient external granular layer (EGL) of the developing cerebellum, where granule cells coordinate a series of mitotic and migratory events. By integrating image segmentation, three-dimensional reconstruction, and deep-learning approaches, we found and characterized anatomically complex intercellular connections bridging pairs of cerebellar granule cells throughout the EGL. Connected cells were either mitotic, migratory, or transitioning between these two cell stages, displaying a chronological continuum of proliferative and migratory events never previously observed in vivo at this resolution. This unprecedented ultrastructural characterization poses intriguing hypotheses about intercellular connectivity between developing progenitors and its possible role in the development of the central nervous system.

Abstract 331: Mitochondrial transfer from astrocytes drives glioblastoma tumorigenicity

Abstract Mitochondrial transfer in the central nervous system occurs from astrocytes to neurons in stroke. Mitochondrial exchange has also been reported among tumor cells in glioblastoma (GBM), the most common primary brain tumor. However, the role of mitochondrial transfer from non-neoplastic cells in the surrounding microenvironment to GBM remains poorly understood. We hypothesized that mitochondrial transfer from these non-neoplastic to GBM cells supports tumor metabolism and growth. Using transgenic mice expressing fluorophore-tagged mitochondria, we found that ~50% of orthotopically-implanted mouse GBM cells acquire host mitochondria. Brain-resident cells, mainly astrocytes, but not infiltrating immune cells were the primary mitochondrial donors in vivo and in vitro. Mitochondrial transfer also occurred from immortalized human astrocytes to a broad array of patient-derived xenograft (PDX) models of GBM in vitro at rates of 15-35%. GBM cells that acquired mitochondria expressed higher levels of the ATP-synthase subunit ATP5A and produced more ATP, while metabolomics revealed upregulated amino acid metabolism in recipient cells. In vivo, mouse GBM cells that acquired mitochondria were more likely to be in G2/M proliferative cell cycle phases. We observed a similar effect in PDX that acquired astrocyte mitochondria from co-cultures in vitro. To mechanistically link increased proliferation specifically to mitochondrial transfer, we isolated astrocyte mitochondria by differential centrifugation and found that addition and uptake of cell-free mitochondria in human GBM cells recapitulated the increased proliferation. Using sorted mouse and human GBM cells with/without astrocyte mitochondrial acquisition, we further found that mitochondrial transfer promoted in vitro self-renewal and in vivo tumorigenicity, leading to significant reduction in survival and increased penetrance in orthotopic GBM models. Transfer in mouse and human systems was contact-dependent and was abrogated by physical separation of donor and recipient cells by transwell inserts. We visualized contact-dependent transfer across actin-based intercellular connections consistent with previously reported microtubes. We confirmed the critical role of actin and the actin-associated protein, growth-associated protein 43 (GAP43) in facilitating mitochondrial transfer by showing that pharmacologic inhibition and genetic knockdown (respectively) significantly decreased the rate of mitochondrial transfer. Taken together, mitochondrial transfer comprises a fundamental, protumorigenic mechanism of GBM, enhancing metabolic activity and driving tumor cell proliferation. Further elucidating the molecular machinery regulating astrocyte mitochondrial transfer and its downstream protumorigenic effects will lead to therapeutic opportunities targeting this understudied tumor microenvironment interaction. Citation Format: Dionysios C. Watson, Defne Bayik, Simon Storevik, Shannon S. Moreino, Samuel S. Sprowls, Gauravi Deshpande, Palavalasa Sravya, Costas A. Lyssiotis, Daniel R. Wahl, Hrvoje Miletic, Justin D. Lathia. Mitochondrial transfer from astrocytes drives glioblastoma tumorigenicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 331.

Intestinal permeability and its role in the pathogenesis of metabolic disorders (metabolic syndrome). Literature review

The article highlights the role of intestinal barrier permeability in the pathogenesis of «metabolic diseases» (diabetes, obesity, etc.). It has been shown that normal intestinal microbiota plays an important role in maintaining the integrity of the intestinal epithelial barrier, and disruption of its homeostasis significantly affects not only intestinal permeability, but also systemic inflammatory processes, immune function, insulin resistance, and lipid metabolism. It was determined that the «Western» diet provides the microbiota with the tools necessary to counteract the host’s immune system and that these changes can destroy the intestinal barrier and contribute to the development of metabolic endotoxinemia. The increased intestinal permeability to endotoxin plays a key role in the development of metabolic changes due to increased translocation of bacterial waste products and contributes to the development of both local and systemic low‑grade inflammation. Intestinal microbiota, affecting metabolic processes in adipose tissue and liver due to impaired intestinal permeability, can ultimately affect systemic insulin resistance and glucose dysregulation. Alterations in the relationship between intestinal immune cells and the microbiome result in the aberrant inflammatory distortions, they are associated with intestinal barrier disruption, metabolic disease progression, and insulin resistance. Intestinal immune cells make an additional contribution to the metabolic disease by regulating the bioavailability of gastrointestinal hormones, which subsequently control blood glucose levels and also affect intestinal barrier permeability. Abnormalities in the tight junctions of intercellular connections in the intestine are associated with metabolic and inflammatory diseases. Disturbance of the intestinal barrier function has been confirmed both in animal models of metabolic‑associated diseases and in human studies, and it is indicated that this barrier dysfunction is an important cause of the metabolic syndrome. Data on the effect of lifestyle adjustments (dietary changes, exercise) and therapeutic strategies (metformin, pre‑ and probiotics, bariatric surgery) on intestinal permeability have been presented.

Role of pectinate muscle in the morphofunctional regulation of the contractile activity of the heart: a review

The pectinate muscles are located on the inner surface of the right and left atria, but their functional significance remains unknown. This review describes the development of pectinate muscles at the molecular-genetic level, the features of ion channels and intercellular connections that allow pectinate to provide rapid conduction of excitation for the coordinated work of the atria and examines the influence of pectinate muscles on the development of atrial fibrillation.

Effects of drying treatment-induced changes in the physicochemical properties of starch on the textural characteristics of Ginkgo seed crisps

Changes in the physicochemical behavior of starch affect texture formation during the processing of Ginkgo seeds. Novel Ginkgo seed crisps come from explosion puffing drying combined with freeze drying (EPD-FD) or from freeze drying combined with explosion-puffing drying (FD-EPD). During EPD-FD, puffing power decreased due to higher tissue resistance, and tighter intercellular connections of starch due to the generation of a new diffraction peak during explosion puffing pre-drying (EPPD). The crystal structure of starch was destroyed during further FD, resulting in low porosity and quality. In the FD-EPD process, freeze pre-drying (FPD) prompted the generation of loose starch particles, crystal structure changes, and large pores and water migration channels. Further, EPD produces a more significant puffing force, which causes greater damage to starch granules and breaks the hydrogen bonds. It forms large pores and high porosity and brittleness, concomitant with a better texture structure.

Nanostructure Mediated Piezoelectric Effect of Tetragonal BaTiO3 Coatings on Bone Mesenchymal Stem Cell Shape and Osteogenic Differentiation.

In recent years, porous titanium (Ti) scaffolds with BaTiO3 coatings have been designed to promote bone regeneration. However, the phase transitions of BaTiO3 have been understudied, and their coatings have yielded low effective piezoelectric coefficients (EPCs < 1 pm/V). In addition, piezoelectric nanomaterials bring many advantages in eliciting cell-specific responses. However, no study has attempted to design a nanostructured BaTiO3 coating with high EPCs. Herein, nanoparticulate tetragonal phase BaTiO3 coatings with cube-like nanoparticles but different effective piezoelectric coefficients were fabricated via anodization combining two hydrothermal processes. The effects of nanostructure-mediated piezoelectricity on the spreading, proliferation, and osteogenic differentiation of human jaw bone marrow mesenchymal stem cells (hJBMSCs) were explored. We found that the nanostructured tetragonal BaTiO3 coatings exhibited good biocompatibility and an EPC-dependent inhibitory effect on hJBMSC proliferation. The nanostructured tetragonal BaTiO3 coatings of relatively smaller EPCs (<10 pm/V) exhibited hJBMSC elongation and reorientation, broad lamellipodia extension, strong intercellular connection and osteogenic differentiation enhancement. Overall, the improved hJBMSC characteristics make the nanostructured tetragonal BaTiO3 coatings promising for application on implant surfaces to promote osseointegration.

Tryptase activates enteric glial cells followed by affecting neuronal properties possibly via the stimuli-associated mediators

ObjectivesMast cell-derived tryptase causes neuronal elongation/sensitization leading to visceral hypersensitivity. However, effects of tryptase on enteric glial cells (EGCs) and subsequent interaction between EGCs and neurons remain unknown. MethodsWe evaluated proteins and mRNA expressions in EGC (CRL-2690, ATCC) after tryptase stimulation: nerve growth factor (NGF), netrin-1, and glial cell-derived neurotrophic factor (GDNF). We examined morphological changes in neurons (PC12 cells, CRL-1721.1) by co-incubation with the conditioned medium of EGCs after tryptase stimulation. ResultsEGC was activated by tryptase, and proliferated (by 1.8-fold) with cytoplasmic expansion and process elongation. Intercellular connections of EGC were more complexed. Tryptase induced mRNA expression (2.5-fold) and protein expression of NGF. Netrin-1 (3-fold) and GDNF (3-fold) mRNA expressions were increased at 30 min. Increase in netrin-1 continued until 6 h, whereas the latter decreased by 3 h. The conditioned medium of EGC after tryptase stimulation expanded neuronal cytoplasm (round or ramified shapes) and neurite outgrowth with elongation of cytoskeletal filaments in time-dependent and dose-dependent manners. These changes were similar to those after NGF stimulation. Growth cone proteins of neurons were also increased by the conditioned medium. ConclusionEGC activated by tryptase changes neuronal morphology (process elongation and cytoplasm expansion) possibly via the stimuli-associated mediators.

Conduction of excitation waves and reentry drift on cardiac tissue with simulated photocontrol-varied excitability.

The development of new approaches to suppressing cardiac arrhythmias requires a deep understanding of spiral wave dynamics. The study of spiral waves is possible in model systems, for example, in a monolayer of cardiomyocytes. A promising way to control cardiac excitability in vitro is the noninvasive photocontrol of cell excitability mediated by light-sensitive azobenzene derivatives, such as azobenzene trimethylammonium bromide (AzoTAB). The trans-isomer of AzoTAB suppresses spontaneous activity and excitation propagation speed, whereas the cis isomer has no detectable effect on the electrical properties of cardiomyocyte monolayers; cis isomerization occurs under the action of near ultraviolet (UV) light, and reverse isomerization occurs when exposed to blue light. Thus, AzoTAB makes it possible to create patterns of excitability in conductive tissue. Here, we investigate the effect of a simulated excitability gradient in cardiac cell culture on the behavior and termination of reentry waves. Experimental data indicate a displacement of the reentry wave, predominantly in the direction of lower excitability. However, both shifts in the direction of higher excitability and shift absence were also observed. To explain this effect, we reproduced these experiments in a computer model. Computer simulations showed that the explanation of the mechanism of observed drift to a lower excitability area requires not only a change in excitability coefficients (ion currents) but also a change in the diffusion coefficient; this may be the effect of the substance on intercellular connections. In addition, it was found that the drift direction depended on the observation time due to the meandering of the spiral wave. Thus, we experimentally proved the possibility of noninvasive photocontrol and termination of spiral waves with a mechanistic explanation in computer models.

The expression and significance of protease activated receptor 2 in ovarian epithelial carcinoma

Objective: To investigate the expression and significance of protease activated receptor 2 (PAR2) in ovarian epithelial carcinoma. Methods: PAR2 mRNA expression levels in 410 cases of epithelial ovarian carcinoma and 88 cases of human normal ovary were analyzed from cancer Genome Atlas (TCGA) database and tissue genotypic expression database (GTEx). Immunohistochemical (IHC) staining of PAR2 protein was performed in 149 patients with ovarian cancer who underwent primary surgical treatment at Cancer Hospital of Chinese Academy of Medical Sciences. Then the relationship between mRNA/protein expression of PAR2 and clinicopathological features and prognosis was analyzed. Gene functions and related signaling pathways involved in PAR2 were studied by enrichment analysis. Results: The mRNA expression of PAR2 in epithelial ovarian carcinoma was significantly higher than that in normal ovarian tissue (3.05±0.72 vs. 0.33±0.16, P=0.004). There were 77 cases showing positive and 19 showing strong positive of PAR2 IHC staining among the 149 patients, accounting for 64.4% in total. PAR2 mRNA/protein expression was closely correlated with tumor reduction effect and initial therapeutic effect (P<0.05). Survival analysis showed that the progression free survival time (P=0.033) and overall survival time (P=0.011) in the group with high PAR2 mRNA expression was significantly lower than that in the low PAR2 mRNA group. Multivariate analysis showed tumor reduction effect, initial therapeutic effect were independent prognostic factors on both progression-free survival and overall survival (P<0.05). The progression-free survival (P=0.016) and overall survival (P=0.038) of the PAR2 protein high expression group was significantly lower than that of the low group. Multivariate analysis showed PAR2 expression, initial treatment effect and chemotherapy resistance were independent prognostic factors on both progression-free survival and overall survival (P<0.05). Based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), PAR2 target genes were mainly enriched in function related to intercellular connection, accounting for 40%. Gene enrichment analysis (GSEA) showed that the Wnt/β-catenin signaling pathway (P=0.023), the MAPK signaling pathway (P=0.029) and glycolysis related pathway (P=0.018) were enriched in ovarian cancer patients with high PAR2 mRNA expression. Conclusions: PAR2 expression is closely related to tumor reduction effect, initial treatment effect and survival of ovarian cancer patients. PAR2 may be involved in Wnt/β-catenin signaling pathway and intercellular connection promoting ovarian cancer invasion and metastasis.

Phototaxis of Chlamydomonas arises from a tuned adaptive photoresponse shared with multicellular Volvocine green algae.

A fundamental issue in biology is the nature of evolutionary transitions from unicellular to multicellular organisms. Volvocine algae are models for this transition, as they span from the unicellular biflagellate Chlamydomonas to multicellular species of Volvox with up to 50,000 Chlamydomonas-like cells on the surface of a spherical extracellular matrix. The mechanism of phototaxis in these species is of particular interest since they lack a nervous system and intercellular connections; steering is a consequence of the response of individual cells to light. Studies of Volvox and Gonium, a 16-cell organism with a plate-like structure, have shown that the flagellar response to changing illumination of the cellular photosensor is adaptive, with a recovery time tuned to the rotation period of the colony around its primary axis. Here, combining high-resolution studies of the flagellar photoresponse of micropipette-held Chlamydomonas with 3D tracking of freely swimming cells, we show that such tuning also underlies its phototaxis. A mathematical model is developed based on the rotations around an axis perpendicular to the flagellar beat plane that occur through the adaptive response to oscillating light levels as the organism spins. Exploiting a separation of timescales between the flagellar photoresponse and phototurning, we develop an equationof motion that accurately describes the observed photoalignment. In showing that the adaptive timescales in Volvocine algae are tuned to the organisms' rotational periods across three orders of magnitude in cell number, our results suggest a unified picture of phototaxis in green algae in which the asymmetry in torques that produce phototurns arise from the individual flagella of Chlamydomonas, the flagellated edges of Gonium, and the flagellated hemispheres of Volvox.

Effects of docosahexaenoic acid or arachidonic acid supplementation on the behavior of cardiomyocytes derived from human pluripotent stem cells

<b>Background:</b> Human heart changes its energetic substrates from lactate and glucose to fatty acids during the neonatal period. Noticing the lack of fatty acids in media for the culture of cardiomyocytes derived from human pluripotent stem cells (hiPS-CM), researchers have supplemented mixtures of fatty acids to hiPS-CM and reported the enhancement in the maturation of hiPS-CM. In our previous studies, we separately supplemented two polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA) or arachidonic acid (AA), to rat fetal cardiomyocytes and found that the supplementations upregulated the expressions of mRNAs for cardiomyocyte differentiation, fatty acid metabolism, and cellular adhesion. The enhancement in cellular contractility was attributed to the improvement in intercellular connection rather than a direct enhancement of the contractile force. <b>Methods:</b> This study reports the successive results of the effects of DHA or AA supplementation on hiPS-CM. In addition to the contractile force and mRNA measurements used in the previous study, we further investigated the effect of different cellular aggregations on the contractile force output by means of finite element analysis, measured glucose and fatty acids metabolites, and assessed cTNT and MLC2v expressions through immunofluorecsence evaluation. <b>Results:</b> It showed that the sole supplementation of albumin-conjugated DHA or AA can be taken up by hiPS-CM without other uptake-enhancing factors, and the supplementations may activate the CD36_­ERRγ metabolic pathway. DHA or AA supplementation increased the cellular contractile ratio on collagen gels and AA supplementation stimulated hiPS-CM aggregation to form cellular clusters. The enhancement effect on the hiPS-CM contractile force was modest since the increase in contractile force was not significant. AA supplementation was more effective than DHA supplementation because it significantly upregulated mRNA expressions of <i>P300</i> and <i>CD36</i>. However, finite element analysis showed that the formation of clusters on a collagen gel attenuated the contractile force exerted by the gel on its surroundings. <b>Conclusion:</b> DHA and AA, as having been supplemented in infant formulas, have no direct and significant enhancement effect on the performance of the hiPS-CM when they were supplemented individually, although they were able to enter the cellular metabolic system. The AA supplementation showed some auxiliary effect on the maturation of hiPS-CM, which is worthy of further investigation under the consideration of membrane composition alteration and remodeling of membrane molecules.

Disease-associated oligodendrocyte signatures in neurodegenerative disease: the known and unknown.

Disease-associated oligodendrocyte signatures in neurodegenerative disease: the known and unknown.

Exploring cell surface markers and cell-cell interactions of human breast milk stem cells.

Breakthrough studies have shown that pluripotent stem cells are present in human breast milk. The expression of pluripotency markers by breast milk cells is heterogeneous, relating to cellular hierarchy, from early-stage multi-lineage stem cells to fully differentiated mammary epithelial cells, as well as weeks of gestation and days of lactation. Here, we qualitatively analyze cell marker expression in freshly isolated human breast milk cells, without any manipulation that could influence protein expression. Moreover, we use electron microscopy to investigate cell-cell networks in breast milk for the first time, providing evidence of active intercellular communication between cells expressing different cellular markers. The immunocytochemistry results of human breast milk cells showed positive staining in all samples for CD44, CD45, CD133, and Ki67 markers. Variable positivity was present with P63, Tβ4 and CK14 markers. No immunostaining was detected for Wt1, nestin, Nanog, OCT4, SOX2, CK5, and CD34 markers. Cells isolated from human breast milk form intercellular connections, which together create a cell-to-cell communication network. Cells freshly isolated form human breast milk, without particular manipulations, show heterogeneous expression of stemness markers. The studied milk staminal cells show "pluripotency" at different stages of differentiation, and are present as single cells or grouped cells. The adjacent cell interactions are evidenced by electron microscopy, which showed the formation of intercellular connections, numerous contact regions, and thin pseudopods.

Incidental nanoparticles in black tea alleviate DSS-induced ulcerative colitis in BALB/c mice.

As the dominant herbal drink consumed worldwide, black tea exhibits various health promoting benefits including amelioration of inflammatory bowel diseases. Despite extensive studies on the tea's components, little is known about the bioactivities of nanoparticles (NPs) which were incidentally assembled in the tea infusion and represent the major components. This study investigated the alleviative effects of black tea infusion, the isolated black tea NPs, and a mixture of caffeine, epigallocatechin-3-gallate, gallic acid and epicatechin gallate on dextran sodium sulfate (DSS)-induced ulcerative colitis. The results showed that both the black tea infusion and the NPs significantly alleviated colitis, suppressed the mRNA levels of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β, and suppressed the DSS-induced loss of cell-cell junction proteins (e.g., E-cadherin, ZO-1, and claudin-1) and increase of p-STAT3. The mixture of four tea components, which is the analogue of bioactive payloads carried by the NPs, was much less effective than the tea infusion and NPs. It shows that the NPs elevate the efficiency of polyphenols and caffeine in black tea in restoring the intercellular connection in the intestine, inhibiting mucosal inflammation, and alleviating ulcerative colitis. This work may inspire the development of tea-based therapeutics for treating inflammatory bowel diseases and have wide influences on value-added processing, quality evaluation, functionalization, and innovation of tea and other plant-based beverages.

Observation of topological action potentials in engineered tissues

The interface between two tissues can have very different bioelectrical properties compared to either tissue on its own. Here we show that an interface between non-excitable tissues can be electrically excitable because of an interaction between the currents passing through the gap junctions—electrically resistive intercellular connections—and the non-linear current–voltage dependence in the ion channels on either side of the interface. Our theory shows that this topologically robust excitability occurs over a far larger range of ion channel expression levels than can support excitability in the bulk. The corresponding interfacial action potentials can cause local elevations in calcium concentration, possibly providing a bioelectrical mechanism for interface sensing. The observed topological action potentials point to the possibility of other types of topological effect in electrophysiology and at other diffusively coupled interfaces. Interfaces between non-excitable tissues can be electrically excitable, suggesting a possible bioelectrical mechanism for interface sensing.

Effects of different preservation methods of human iliac veins.

With the progress of vascular anastomosis technology, the radical resection surgery of cancer combining with vascular resection and reconstruction has been focused by surgeon. As a natural substitute material for blood vessel, vascular allografts have good vascular compliance and histocompatibility. Generally, the donated veins could not be used immediately, and need to be well preserved. So, it is greatly significant to do research in the preservation effects of different preservation methods on veins. In this study, the effects of different preservative methods of human iliac veins were compared and analyzed in terms of cell viability, vascular wall structure and tension resistance. The donated human iliac veins were randomly divided into three groups: Cold Storage Group (4 °C) (CSG), Frozen Storage Group (-186 °C) (FSG)and Fresh Control Group (FCG). Six detection time-points of preservation for 1, 3, 5, 7, 14, 28days were set respectively. There are ten samples in each group and each time-point separately. Survival and apoptosis of vascular cell were evaluated by MTT assay and Tunel fluorescence staining. Tensile test was used to evaluate mechanical properties of vessels. The changes of vascular endothelial cells, smooth muscle cells, collagen fibers and elastic fibers were evaluated by HE staining, Masson staining and EVG staining. Furthermore, the changes of organelles were observed by transmission electron microscope. With the extension of preservation period, the vascular cell viability and tension resistance of two groups decreased, and the apoptotic cells increased gradually. The apoptosis index of CSG was higher than FSG at each time point (P < 0.05). In terms of cell viability, CSG was higher within 3days (P < 0.05), both groups were same between 3 and 14days, and then CSG lower than FSG after 14days (P < 0.05). In terms of tension resistance, CSG was stronger than FSG (P < 0.05) in first 7days, both groups were same in 2nd week, and then CSG was weaker in 4th week (P < 0.05). In terms of vascular wall structure, in CSG, vascular endothelial cells were damaged and shed, smooth muscle cells were edema after 14days, but the cell membrane and intercellular connection were still intact. In 4th week, endothelial cells were completely damaged and shed, the boundary of smooth muscle cell membrane was unclear, intercellular connection was damaged. Moreover, organelles were destroyed and disappeared, perinuclear condensation of chromatin was observed, and some cells had incomplete nuclear membrane or nuclear fragmentation; However, there were no obvious changes in the FSG within 28days. Finally, local exfoliation and destruction of endothelial cells and edema-like changes of organelles were observed; the collagen fibers and elastic fibers of blood vessels in the two groups had no obvious damage and change within 28days. For excised human iliac vein, cold and frozen storage can effectively preserve the cell viability, wall structure and tension resistance of blood vessels. With the extension of preservation time, the related performance of vessels declined in varying degrees. Within first week, the effect of cold storage is better than frozen storage, but frozen storage is significantly better than cold storage after 2weeks.

Single-cell transcriptomic, transcriptomic, and metabolomic characterization of human atherosclerosis

Atherosclerosis is the main cause of many cardiovascular and cerebrovascular diseases (CVDs), and gaining a deeper understanding of the intercellular connections and key central genes which mediate formation of atherosclerotic plaques is required. We performed a comprehensive bioinformatics analysis of differential genetic screening, Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway annotation, protein-protein interactions (PPIs), pseudo-timing, intercellular communication, transcription factors on carotid single-cell sequencing data, and aortic bulk transcriptome and metabolomic data. Ten cell types were identified in the data: T cells, monocytes, smooth muscle cells, endothelial cells, B cells, fibroblasts, plasma cells, mast cells, dendritic cells, and natural killer cells. Endothelial, fibroblast, macrophage, and smooth muscle cell subtype differentiation trajectories, interaction networks, and important transcription factors were characterized in detail. Finally, using this information combined with transcriptome and metabolome analyses, we found the key genes and signaling pathways of atherosclerosis, especially the advanced glycation end products and receptor for advanced glycation end products signaling pathway (AGE-RAGE signaling pathway) in diabetic complications, linked the differential metabolites with fibroblasts and atherosclerosis and contributed to it in patients with diabetes. Collectively, this study provides key genes, signaling pathways, cellular communication, and transcription factors among endothelial cells, fibroblasts, macrophages, and smooth muscle cells for the study of atherosclerotic plaques, and provides a basis for the diagnosis and treatment of atherosclerosis-like sclerosis.