Adhesion Proteins Research Articles

Does rAj-Tspin, a novel peptide from A. japonicus, exert antihepatocellular carcinoma effects via the ITGB1/ZYX/FAK/AKT signaling pathway?

rAj-Tspin, a soluble recombinant peptide from Apostichopus japonicus, can inhibit the integrin β1 (ITGB1)/FAK/AKT signaling pathway in hepatocellular carcinoma (HCC) via cell epithelial–mesenchymal transition (EMT) and apoptosis. Zyxin (ZYX) is a focal adhesion protein that is considered a novel mediator of EMT and apoptosis. However, the inhibitory mechanisms of rAj-Tspin in HCC and whether it is related to ZYX are unclear. We examined the antitumor effect of rAj-Tspin on the Huh7 human HCC cell line and on a nude mouse model generated via subcutaneous injection or orthotopic intrahepatic transplantation of Huh7 cells. Our results revealed that rAj-Tspin strikingly reduced the viability and promoted the apoptosis of Huh7 cells and inhibited HCC tumor growth in nude mice. rAj-Tspin inhibited ITGB1 and ZYX protein expression in vivo and in vitro in a dose-dependent manner. Mechanistically, the FAK/AKT signaling pathway and the proliferation and invasion of HCC cells were suppressed upon ITGB1 and ZYX knockdown. Moreover, the effect of ITGB1 overexpression on the growth of HCC cells was inhibited by rAj-Tspin. In contrast, the promoting effect of ITGB1 overexpression could be inhibited by ZYX knockdown. ZYX knockdown had no effect on ITGB1 expression. These findings suggest that ZYX is required for the indispensable role of ITGB1 in rAj-Tspin‐alleviated HCC and provide an important therapeutic target for HCC. In summary, the anti-HCC effect of rAj-Tspin potentially involves the regulation of the ITGB1/ZYX/FAK/AKT pathway, which in turn impacts EMT and apoptosis.Graphical

Recyclable thermo-responsive elastin-based adhesives with tough underwater adhesion and rapid hemostasis ability

Protein-based underwater adhesives have attracted tremendous attention due to their excellent biocompatibility compared to adhesives prepared with synthetic polymers. However, the fabrication of protein-based adhesives always requires multiple successive steps, and their underwater adhesion is quite limited. Inspired by the human elastic fibers, bone matrix, and marine adhesive proteins, a thermo-responsive underwater adhesive was fabricated through a facial one-step complexation of elastin (ELN), hydroxyapatite (HAP), and tannic acid (TA) based on multiple non-covalent molecular interactions. During underwater adhesion, the adhesive can perform sufficient flowability to adhere seamlessly and strongly to the substrates upon heating at 37 ℃ and then significantly increase its cohesion through cooling down to 25 ℃ to sustain adhesion. The regulation of the balance between adhesion and cohesion in response to temperature change enables the adhesive to exhibit a robust underwater adhesion ranging from 0.3 to 1.1 MPa to the substrates with low, medium, or high surface energy, outperforming most protein-based adhesives. Importantly, the adhesive can be further processed into powders with well-maintained underwater adhesion by a simple drying and grinding method, facilitating adhesion onto irregular-shaped target sites, reusability, and closed-loop recycling. The adhesive powder also possesses a rapid in vivo hemostatic property, suggesting a potential biomedical application.

Discovery of essential kinetoplastid-insect adhesion proteins and their function in Leishmania-sand fly interactions

Leishmania species, members of the kinetoplastid parasites, cause leishmaniasis, a neglected tropical disease, in millions of people worldwide. Leishmania has a complex life cycle with multiple developmental forms, as it cycles between a sand fly vector and a mammalian host; understanding their life cycle is critical to understanding disease spread. One of the key life cycle stages is the haptomonad form, which attaches to insect tissues through its flagellum. This adhesion, conserved across kinetoplastid parasites, is implicated in having an important function within their life cycles and hence in disease transmission. Here, we discover the kinetoplastid-insect adhesion proteins (KIAPs), which localise in the attached Leishmania flagellum. Deletion of these KIAPs impairs cell adhesion in vitro and prevents Leishmania from colonising the stomodeal valve in the sand fly, without affecting cell growth. Additionally, loss of parasite adhesion in the sand fly results in reduced physiological changes to the fly, with no observable damage of the stomodeal valve and reduced midgut swelling. These results provide important insights into a comprehensive understanding of the Leishmania life cycle, which will be critical for developing transmission-blocking strategies.

Anchorless Bacterial Moonlighting Metabolic Enzymes Modulate the Immune System and Contribute to Pathogenesis.

Moonlighting proteins (MPs), characterized by their ability to perform multiple physiologically unrelated functions without alterations to their primary structures, represent a fascinating class of biomolecules with significant implications for host-pathogen interactions. This Review highlights the emerging importance of metabolic moonlighting proteins (MetMPs) in bacterial pathogenesis, focusing on their non-canonical secretion and unconventional surface anchoring mechanisms. Despite lacking typical signal peptides and anchoring motifs, MetMPs such as acetaldehyde alcohol dehydrogenase (AdhE) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) are secreted and localized to the bacterial surface under stress conditions, facilitating host colonization and immune evasion. The secretion of MetMPs, often observed during conditions such as resource scarcity or infection, suggests a complex regulation akin to the overexpression of heat shock proteins in response to environmental stresses. This Review proposes two potential pathways for MetMP secretion: membrane damage-induced permeability and co-transportation with traditionally secreted proteins, highlighting a remarkable bacterial adaptability. Biophysically, surface anchoring of MetMPs is driven by electrostatic interactions, bypassing the need for conventional anchoring sequences. This mechanism is exemplified by the interaction between the bifunctional enzyme AdhE (known as Listeria adhesion protein, LAP) and the internalin B (InlB) in Listeria monocytogenes, which is mediated by charged residues facilitating adhesion to host tissues. Furthermore, MetMPs play critical roles in iron homeostasis, immune modulation, and evasion, underscoring their multifaceted roles in bacterial pathogenicity. The intricate dynamics of MetMP secretion and anchoring underline the need for further research to unravel the molecular mechanisms underpinning these processes, offering potential new targets for therapeutic intervention against bacterial infections.

Molecular signatures of normal pressure hydrocephalus: a large-scale proteomic analysis of cerebrospinal fluid

Given the persistent challenge of differentiating idiopathic Normal Pressure Hydrocephalus (iNPH) from similar clinical entities, we conducted an in-depth proteomic study of cerebrospinal fluid (CSF) in 28 shunt-responsive iNPH patients, 38 Mild Cognitive Impairment (MCI) due to Alzheimer’s disease, and 49 healthy controls. Utilizing the Olink Explore 3072 panel, we identified distinct proteomic profiles in iNPH that highlight significant downregulation of synaptic markers and cell-cell adhesion proteins. Alongside vimentin and inflammatory markers upregulation, these results suggest ependymal layer and transependymal flow dysfunction. Moreover, downregulation of multiple proteins associated with congenital hydrocephalus (e.g., L1CAM, PCDH9, ISLR2, ADAMTSL2, and B4GAT1) points to a possible shared molecular foundation between congenital hydrocephalus and iNPH. Through orthogonal partial least squares discriminant analysis (OPLS-DA), a panel comprising 13 proteins has been identified as potential diagnostic biomarkers of iNPH, pending external validation. These findings offer novel insights into the pathophysiology of iNPH, with implications for improved diagnosis.

ECM components are essential for proper in vitro myogenesis

Objective: In vitro models of skeletal muscle often utilize primary myoblast cells or myoblast cell lines. Myoblasts require adhesion to the extracellular matrix (ECM) to grow, proliferate, migrate, and differentiate in their natural environments in vivo. To meet the adhesion needs of adhesive cells under in vitro conditions, culture surfaces are coated with various biological or synthetic compounds. Within the scope of the study, the differentiation potential of H2K myoblasts, a cell line resembling primary myoblasts, were comparatively evaluated through morphological analysis on culture surfaces coated with various ECM and synthetic materials. Methods: The culture surfaces were coated with fibronectin and laminin, the major adhesion proteins of ECM; gelatin, a molecular derivative of collagen; matrigel, an ECM extract; and PLL, a synthetic poly-amino acid. Cells were allowed to differentiate in each culture medium for 4 days and their capacity to adhere to the surface and differentiation rates from myoblast to myotube were evaluated by morphological analysis. Results: In the uncoated culture environment, cells could only attach to 30-50% of the culture surface and myotube development was limited and not aligned with each other. On surfaces coated with PLL, no myotube development was observed and cells could only attach to 30-40% of the culture surface. Myotube development and alignment were similar on all surfaces coated with ECM components. On surfaces coated with ECM components laminin, fibronectin and matrigel, cells covered the entire culture surface and exhibited similar myotube development. However, on surfaces coated with gelatin, both cell adhesion to the surface and myotube development were limited compared to other ECM components. The mean myotube diameters of fibronectin, laminin, matrigel, PLL+laminin and gelatin were 49.71µm (±16.3µm), 52.31µm (±15.7µm), 51.9µm (±15.3µm), 53.06µm (±14.2µm) and 35.25µm (±11.4µm), respectively. Conclusion: Within the scope of the study, it was revealed that coating the culture surface with only a cationic material such as PLL does not support myogenesis and ECM components are needed for cell viability and differentiation.

Neuroprotection by ADAM10 inhibition requires TrkB signaling in the Huntington’s disease hippocampus

Synaptic dysfunction is an early pathogenic event leading to cognitive decline in Huntington’s disease (HD). We previously reported that the active ADAM10 level is increased in the HD cortex and striatum, causing excessive proteolysis of the synaptic cell adhesion protein N-Cadherin. Conversely, ADAM10 inhibition is neuroprotective and prevents cognitive decline in HD mice. Although the breakdown of cortico-striatal connection has been historically linked to cognitive deterioration in HD, dendritic spine loss and long-term potentiation (LTP) defects identified in the HD hippocampus are also thought to contribute to the cognitive symptoms of the disease. The aim of this study is to investigate the contribution of ADAM10 to spine pathology and LTP defects of the HD hippocampus. We provide evidence that active ADAM10 is increased in the hippocampus of two mouse models of HD, leading to extensive proteolysis of N-Cadherin, which has a widely recognized role in spine morphology and synaptic plasticity. Importantly, the conditional heterozygous deletion of ADAM10 in the forebrain of HD mice resulted in the recovery of spine loss and ultrastructural synaptic defects in CA1 pyramidal neurons. Meanwhile, normalization of the active ADAM10 level increased the pool of synaptic BDNF protein and activated ERK neuroprotective signaling in the HD hippocampus. We also show that the ADAM10 inhibitor GI254023X restored LTP defects and increased the density of mushroom spines enriched with GluA1-AMPA receptors in HD hippocampal neurons. Notably, we report that administration of the TrkB antagonist ANA12 to HD hippocampal neurons reduced the beneficial effect of GI254023X, indicating that the BDNF receptor TrkB contributes to mediate the neuroprotective activity exerted by ADAM10 inhibition in HD. Collectively, these findings indicate that ADAM10 inhibition coupled with TrkB signaling represents an efficacious strategy to prevent hippocampal synaptic plasticity defects and cognitive dysfunction in HD.

Unveiling the role of RhoA and ferroptosis in vascular permeability: Implications for osteoarthritis.

Abnormal angiogenesis and increased vascular permeability of subchondral bone are key mechanisms related to osteoarthritis (OA). However, the precise mechanisms responsible for heightened vascular permeability in OA remain unclear. The present study used proteomics to identify protein expression in damaged subchondral bone compared with normal subchondral bone. The results suggest that Ras homolog family member A (RhoA) may be associated with the vascular permeability of subchondral bone and ferroptosis in OA. The results of analysis of clinical samples indicated a significant increase in expression of RhoA in the subchondral bone of OA. This were consistent with the proteomics findings. We found through western blotting, RT‑PCR, and immunofluorescence that RhoA significantly increased the permeability of endothelial cells (ECs) by inhibiting inter‑EC adhesion proteins (zona occludens‑1, connexin 43 and Vascular endothelial‑Cadherin) and actin filaments. Furthermore, RhoA induced ferroptosis core proteins (glutathione peroxidase 4, solute carrier family 7 member 11 and acyl‑CoA synthase long‑chain family member 4, ACSL4) by influencing lipid peroxidation and mitochondrial function, leading to ferroptosis of ECs. This suggested an association between RhoA, ferroptosis and vascular permeability. Ferroptosis significantly increased permeability of ECs by inhibiting inter‑EC adhesion proteins. RhoA increased vascular permeability by inducing ferroptosis of ECs. In vivo, inhibition of RhoA and ferroptosis significantly mitigated progression of OA by alleviating cartilage degeneration and subchondral bone remodeling in mice with destabilization of the medial meniscus. In conclusion, the present findings indicated that RhoA enhanced vascular permeability in OA by inducing ferroptosis. This may serve as a novel strategy for the early prevention and treatment of OA.

Abstract We040: Molecular Characterization of Human Highly Proliferative Cells Isolated from Coronary Artery Bypass Graft Surgery Patients Identifies IGFBP3, SOST, and ISLR as Downstream Targets of BMP9/ALK1 Signaling

Stem/progenitor cells are being investigated as a potential cell source to reverse cardiac remodeling and restore cardiac function, but the molecular mechanisms required for improved repair are not well understood. Circulating BMP9 is negatively associated with heart disease risk factors. BMP9/ALK1 signaling is a critical pathway involved in several mechanisms of vascular repair such as angiogenesis and inflammation. We recently identified ALK1 expression in human highly proliferative cells (hHiPCs) with progenitor capabilities isolated from patients undergoing coronary artery bypass graft (CABG) surgery as measured by flow cytometry. We have determined that circulating BMP9 in patients is negatively associated with number of hHiPC (p<0.001) and positively associated with endothelial cell (EC) number (p=0.008) suggesting that BMP9 may play a role in hHiPC differentiation into EC. Further, we found upregulation of novel BMP9 regulated proteins, IGFBP3, SOST, and ISLR, in hHiPC upon BMP9 treatment using LC-MS/MS analysis of the secretome (p<0.01, Fold-change (FC)>2.0) and RT-qPCR (p<0.001, FC>2.0). Conditioned media collected from BMP9 treated hHiPCs or ECs improved tube formation in the tube formation assay. IGFBP3, SOST, and ISLR upregulation by BMP9 is inhibited upon knockdown and pharmacological inhibition of ALK1 as measured by proteomics (p<0.01) and RT-qPCR analysis (p<0.05). ISLR is a novel marker of mesenchymal stem cells found to have an important role in maintaining “stemness” and colony formation. hHiPCs treated with novel BMP9 target, ISLR, were analyzed using LC-MS/MS and STRING. We found ISLR treatment enriched for differential regulation of cell adhesion, cell migration, and angiogenesis proteins such as CXCL12, EMILIN1, and ANXA5 (p<0.05). Together, these data lay the foundation for investigating BMP9/ALK1 autocrine signaling in potential regulation of progenitor cell maintenance and angiogenesis in heart disease.

Abstract We122: Suppression of defender against cell death 1 (Dad1) induces cardiomyocyte death by regulating cell adhesion proteins.

Introduction: Suppression of cardiomyocyte loss is considered a promising strategy for the prevention of the onset of heart failure (HF). Previously, defender against cell death 1 ( Dad1 ) was identified as a cytoprotective gene. Dad1 forms a complex with staurosporine and temperature sensitive 3A (Stt3A), a catalytic subunit of oligosaccharyltransferase (OST) complex which is responsible for N-glycosylation. However, the function of Dad1 in cardiomyocytes remains unknown. Hypothesis: The disruption of cell-extracellular matrix interactions results in cell death, known as anoikis. Because various cell adhesion proteins are N-glycosylated, we hypothesized that Dad1 suppressed anoikis by regulating N-glycosylation of cell adhesion proteins in cardiomyocytes. Methods: Neonatal rat cardiomyocytes were cultured and the expression of Dad1 or Stt3A was knocked down using siRNA. The protein expression was assessed with immunoblot analysis, and cell viability was evaluated using a CellTiter-Blue assay kit. Results: The suppression of Dad1 using siRNAs reduced cardiomyocyte viability ( p <0.01, n=4). Interestingly, suppression of Dad1 impaired the N-glycosylation of integrin β1 and decreased the expression of mature integrin β1 ( p <0.01, n=3). These changes inactivated integrin-mediated signal transduction through dephosphorylation of focal adhesion kinase ( p <0.01, n=5). In addition, enhanced cell-extracellular matrix interactions by using adhesamine rescued the cardiomyocyte death by Dad1 knockdown ( p <0.01, n=4). Next, we pursued the relationship between Dad1 and Stt3A. Dad1 knockdown decreased the expression of Stt3A ( p <0.01, n=6). Suppression of Stt3A induced cardiomyocyte death accompanied by the changes of cell adhesion proteins ( p <0.01, n=4). Finally, double knockdown of Dad1 and Stt3A did not induce a further reduction in cell viability compared with the knockdown of only Dad1 ( p <0.05, n=4), suggesting that cardiomyocyte death by Dad1 knockdown was dependent on Stt3A. Conclusion: Dad1 is required for the stabilization of Stt3A and suppresses cardiomyocyte anoikis by regulating N-glycosylation of cell adhesion proteins in an OST-dependent manner. Dad1-mediated cardiomyocyte survival could be a therapeutic target against HF.

Abstract We102: Synthetic N-Acylurea Derivative Reduces Angiogenesis in Human Endothelial Cells by Talin Modulation

Talin is a focal adhesion protein that activates integrins and recruits other focal adhesion proteins. Talin regulates the interactions between integrins and the extracellular matrix, which are critical for endothelial cells during angiogenesis. In this study, we successfully synthesized a novel talin modulator, N-((2-(1H-indol-3-yl)ethyl)carbamoyl)-2-(benzo[d][1,3]dioxol-5-yloxy)acetamide, referred to as KCH-1521. KCH-1521 was determined to bind talin and modulate downstream signaling molecules of talin. After 24 hrs of treatment, KCH-1521 changed the cell morphology of HUVECs and reduced focal adhesion protein expression including vinculin and paxillin. Talin downstream signaling is regulated via FAK, AKT, and ERK pathways, however, treatment with KCH-1521 decreased phosphorylation of FAK, AKT, and ERK, leading to a reduction of cell proliferation, survival, and angiogenesis. Interestingly, the expression of various angiogenic genes was significantly decreased after treatment with KCH-1521. Also, in vitro tube forming assay revealed that KCH-1521 reduced angiogenic networks in a time-dependent manner. To investigate the reversibility of its effects, KCH-1521 was removed after treatment. HUVECs recovered their morphology through rearrangement of the cytoskeleton and the expression of angiogenic genes was also recovered. By further optimization and in vivo studies of KCH-1521, a novel drug of talin modulation could be used to achieve therapeutic anti-angiogenesis for vascular diseases and cancers.

Abstract Or111: Titin cleavage disrupts sarcomere-adhesion tensional homeostasis triggering cardiomyocyte arrhythmia in vitro

The cardiac tissue experiences several forms of mechanical stress, including contraction of cardiomyocytes and forces derived from the stiffness of extracellular matrix (ECM). Preserving homeostatic mechanical forces is crucial for a healthy heart, yet the mechanisms involved are not well-explored. Our study delves into cardiomyocyte responses following the sudden release of mechanical tension across titin, a giant sarcomere protein crucial for setting cardiomyocyte stiffness. Through the expression of virally transduced TEV protease (TEVp) in neonatal mouse cardiomyocytes (NMCMs), we induced the cleavage of mutant titin including the specific TEV protease recognition site (TEVs) within the mechanically active I-band region of the protein. Titin cleavage was validated by 1.8% polyacrylamide SDS-PAGE electrophoresis, revealing a primary band at ~2.2 MDa in TEV-positive NMCMs, corresponding to digested titin fragment A-M. This cleavage, confirmed at 2 days post-infection (dpi) with ~80% efficiency, reached 100% by 5 dpi. Consequently, the Young’s modulus of affected cardiomyocytes dropped by 50%, as determined by Atomic Force Spectroscopy. Sarcomere disarray increased over time, as evidenced by immunofluorescence, yet this effect did not induce cell death or proliferation. Cell viability was confirmed by the fact that affected cardiomyocytes are able to contract spontaneously, although titin cleavage resulted in reduced beating amplitude and induced arrhythmic behavior. Considering this arrhythmogenic situation, we tested cell-cell adhesion through dissociation assays, which revealed significantly reduced intercellular adhesion in affected cardiomyocytes. RNAseq confirmed involvement of pathways related to heart contraction, anchoring junctions, and cell junctions. Specifically, dysregulated genes associated with gap-junction and costamere complexes were observed at 5 dpi. Alterations of adhesion were further confirmed by reductions in connexin 43 and focal adhesion length in immunofluorescence experiments, which also showed mislocalization of important adhesive proteins. In conclusion, titin cleavage in neonatal cardiomyocytes leads to sarcomere disarray, perturbed cell-cell adhesion and arrhythmia. These findings highlight the importance of full mechanical integrity of the titin filament in living cardiomyocytes.

Correction to: Inhibition of the Plasma SCUBE1, a Novel Platelet Adhesive Protein, Protects Mice Against Thrombosis.

Correction to: Inhibition of the Plasma SCUBE1, a Novel Platelet Adhesive Protein, Protects Mice Against Thrombosis.

AB045. E2F6 promotes temozolomide resistance in glioblastoma by enrichment in CARD6 and POSTN promoter region.

Glioblastoma (GBM) is the most aggressive primary malignant brain tumor. Temozolomide (TMZ) is the most used first-line chemotherapeutic agent for GBM after surgery, but acquired resistance to TMZ frequently leads to treatment failure and is a major challenge in the clinical treatment of GBM. Increasing evidence suggests that E2F transcription factor 6 (E2F6) is associated with a variety of tumor malignant biological behaviors and drug resistance, but its biological function and underlying molecular mechanisms in GBM are unknown. The study investigated the levels of E2F6 in both TMZ-sensitive and TMZ-resistant GBM cells and tissues using Western blotting and immunofluorescence assays. In vitro experiments were conducted to explore the impact of E2F6 on TMZ resistance and glioma stem cell stemness. These experiments included Western blotting, colony formation assay, flow cytometry assay, and TdT-mediated dUTP nick-end labeling (TUNEL) assay. Bioinformatic analyses were conducted to investigate the mechanism behind the high expression of E2F6 in TMZ-resistant cells and its correlation with caspase recruitment domain 6 (CARD6) and disulfide-linked cell adhesion protein (POSTN). The study employed bioinformatic analyses, messenger RNA (mRNA) sequencing, chromatin immunoprecipitation sequencing assay, immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. To examine the function of E2F6, an intracranial xenograft tumor mouse model was used for in vivo experiments. It was found that CARD6 and POSTN were significantly associated with TMZ resistance and survival of GBM patients. E2F6 was up-regulated in TMZ-resistant cells and tissues. Knockdown of E2F6 down-regulated the expression of CARD6, promoted TMZ-induced apoptosis, and enhanced chemo-sensitivity, whereas its overexpression significantly increased TMZ resistance in vitro and in vivo. In addition, E2F6 can promote TMZ resistance through stem-like properties acquisition. We identified a signaling pathway related to E2F6 and POSTN, which maintains the self-renewal of GBM stem cells (GSCs). E2F6 concentrates in the promoter region of POSTN, thereby regulating the expression of GSCs-related genes cluster of differentiation 133 (CD133), Nestin, and sex-determining region Y-box 2 (SOX2), which may be involved in tumor metabolism and drug resistance processes. Down-regulation of E2F6 down-regulated the expression of POSTN and inhibited tumor growth in nude mice. These results suggest that the E2F6-CARD6/POSTN signaling axis regulates the malignant biological behaviors of GBM and TMZ resistance. These findings are expected to provide promising therapeutic targets for CARD6 overcoming GBM TMZ resistance.

Loss of primary cilia and dopaminergic neuroprotection in pathogenic LRRK2-driven and idiopathic Parkinson’s disease

Activating leucine-rich repeat kinase 2 (LRRK2) mutations cause Parkinson's and phosphorylation of Rab10 by pathogenic LRRK2 blocks primary ciliogenesis in cultured cells. In the mouse brain, LRRK2 blockade of primary cilia is highly cell type specific: For example, cholinergic interneurons and astrocytes but not medium spiny neurons of the dorsal striatum lose primary cilia in LRRK2-pathway mutant mice. We show here that the cell type specificity of LRRK2-mediated cilia loss is also seen in human postmortem striatum from patients with LRRK2 pathway mutations and idiopathic Parkinson's. Single nucleus RNA sequencing shows that cilia loss in mouse cholinergic interneurons is accompanied by decreased glial-derived neurotrophic factor transcription, decreasing neuroprotection for dopamine neurons. Nevertheless, LRRK2 expression differences cannot explain the unique vulnerability of cholinergic neurons to LRRK2 kinase as much higher LRRK2 expression is seen in medium spiny neurons that have normal cilia. In parallel with decreased striatal dopaminergic neurite density, LRRK2 G2019S neurons show increased autism-linked CNTN5 adhesion protein expression; glial cells show significant loss of ferritin heavy chain. These data strongly suggest that loss of cilia in specific striatal cell types decreases neuroprotection for dopamine neurons in mice and human Parkinson's.

Bioadhesive-Inspired Ionomer for Membrane Electrode Assembly Interface Reinforcement in Fuel Cells.

Anion exchange membrane fuel cells promise a sustainable and ecofriendly energy conversion pathway yet suffer from insufficient performance and durability. Drawing inspiration from mussel foot adhesion proteins for the first time, we herein demonstrate catechol-modified ionomers that synergistically reinforce the membrane electrode assembly interface and triple-phase boundary inside catalyst layers. The resulting ionomers present exceptional alkaline stability with only slight ionic conductivity declines after treatment in 2 M NaOH aqueous solution at 80 °C for 2500 h. Adopting catechol-modified ionomer as both anion exchange membrane and binder achieves a single-cell performance increase of 34%, and more importantly, endows fuel cell operation at a current density of 0.4 A cm-2 for over 300 h with negligible performance degradation (with a cell voltage decay rate of 0.03 mV h-1). Combining theoretical and experimental investigations, we reveal the molecular adhesion mechanism between the catechol-modified ionomer and Pt catalyst and illuminate the effect on the catalyst layer microstructure. Of fundamental interest, this bioadhesive-inspired strategy is critical to enabling knowledge-driven ionomer design and is promising for diverse membrane electrode assembly configurational applications.

Absence of Aquaporin-4 (AQP4) Prolongs the Presence of a CD11c+ Microglial Population during Postnatal Corpus Callosum Development.

Aquaporin-4 (AQP4) expression is associated with the development of congenital hydrocephalus due to its structural role in the ependymal membrane. Gene expression analysis of periaqueductal tissue in AQP4-knockout (KO) mice at 11 days of age (P11) showed a modification in ependymal cell adhesion and ciliary protein expression that could alter cerebrospinal fluid homeostasis. A microglial subpopulation of CD11c+ cells was overexpressed in the periaqueductal tissue of mice that did not develop hydrocephalus, suggesting a possible protective effect. Here, we verified the location of this CD11c+ expression in the corpus callosum (CC) and cerebellum of AQP4-KO mice and analysed its time course. Immunofluorescence labelling of the CD11c protein in the CC and cerebellum of WT and KO animals at P3, P5, P7 and P11 confirmed an expanded presence of these cells in both tissues of the KO animal; CD11c+ cells appeared at P3 and reached a peak at P11, whereas in the WT animal, they appeared at P5, reached their peak at P7 and were undetectable by P11. The gene expression analysis in the CC samples at P11 confirmed the presence of CD11c+ microglial cells in this tissue. Among the more than 4000 overexpressed genes, Spp1 stood out with the highest differential gene expression (≅600), with other genes, such as Gpnmb, Itgax, Cd68 and Atp6v0d2, also identified as overexpressed. Therefore, CD11c+ cells appear to be necessary for normal corpus callosum development during postnatal life, and the absence of AQP4 prolonged its expression in this tissue.

Arrhythmogenic cardiomyopathy-related cadherin variants affect desmosomal binding kinetics

Cadherins are calcium dependent adhesion proteins that establish and maintain the intercellular mechanical contact by bridging the gap between adjacent cells. Desmoglein-2 (Dsg2) and desmocollin-2 (Dsc2) are tissue specific cadherin isoforms of the cell-cell contact in cardiac desmosomes. Mutations in the DSG2-gene and in the DSC2-gene are related to arrhythmogenic right ventricular cardiomyopathy (ARVC) a rare but severe heart muscle disease. Here, several possible homophilic and heterophilic binding interactions of wild-type Dsg2, wild-type Dsc2, as well as one Dsg2- and two Dsc2-variants, each associated with ARVC, are investigated. Using single molecule force spectroscopy (SMFS) with atomic force microscopy (AFM) and applying Jarzynski's equality the kinetics and thermodynamics of Dsg2/Dsc2 interaction can be determined. The free energy landscape of Dsg2/Dsc2 dimerization exposes a high activation energy barrier, which is in line with the proposed strand-swapping binding motif. Although the binding motif is not affected by any of the mutations, the binding kinetics of the interactions differ significantly from the wild-type. While wild-type cadherins exhibit an average complex lifetime of approx. 0.3 s interactions involving a variant consistently show - lifetimes that are substantially larger. The lifetimes of the wild-type interactions give rise to the picture of a dynamic adhesion interface consisting of continuously dissociating and (re)associating molecular bonds, while the delayed binding kinetics of interactions involving an ARVC-associated variant might be part of the pathogenesis. Our data provide a comprehensive and consistent thermodynamic and kinetic description of cardiac cadherin binding, allowing detailed insight into the molecular mechanisms of cell adhesion.

Develop a novel and multifunctional soy protein adhesive constructed by rosin acid emulsion and TiO2 organic-inorganic hybrid structure

Soy protein adhesives (SPI) exhibit broad prospects in substituting aldehyde-based resin due to the economic and environmental-friendly characteristics, but still face a challenge because of the dissatisfied bonding strength and terrible water resistance. Herein, prompted by organic-inorganic hierarchy, a multifunctional and novel soy protein adhesive (SPI-RAE-TiO2) consisting of rosin acid emulsion (RAE) and TiO2 nanoparticles (TiO2) were proposed. In comparison with original SPI, the dry and wet shear strengths of modified adhesive reached 2.01 and 1.21 MPa, respectively, which were increased by 130 % and 200 %. Furthermore, SPI-6RAE-0.5TiO2 was selected as the best proportion via the method of response surface methodology (RSM). What's more, SPI-6RAE-0.5TiO2 adhesive demonstrated prominent coating performance in both dry and wet surface conditions. Meanwhile, SPI-6RAE-0.5TiO2 adhesive possessed excellent mildew resistance and antibacterial ability with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), reflecting the antibacterial rates 97.71 % and 98.16 %, respectively. In addition, SPI-6RAE-0.5TiO2 adhesive also exhibited the outstanding green features such as the reduction of formaldehyde pollution and greenhouse effect through Life Cycle Assessment (LCA). Thus, this work provided a novel and functional approach to design multifunctional, superior-property and low-carbon footprint soy protein adhesive.

Effect of Salicylic Acid on the gene expression of FnbA and FnbB genes in Staphylococcus hominis.

Staphylococcus hominis is an opportunistic pathogen that expresses surface proteins, which are adhesive proteins that play a major role in biofilm formation. Biofilm is a protective layer that provides S. hominis bacteria with greater antibiotic resistance and promotes its adherence to biomedical surfaces, facilitating its entry into the bloodstream. This research aimed to investigate the activity of Salicylic Acid (SA) and its effect on the gene expression of biofilm genes (FnbA and FnbB genes). A total of 150 blood specimens were collected from patients. The specimens were cultured in broth media of the BacT/ALERT® system and subcultured on blood and chocolate agar. Bacteria were detected using the VITEK2 system. FnbA and FnbB genes were detected using PCR. The broth microdilution method performed the minimum inhibitory concentration (MIC) of Salicylic acid (SA) on S. hominis isolates with both genes. Detection of the gene expression levels of FnbA and FnbB genes was assessed using Real-Time PCR(RT-PCR). The results showed that out of the 150 specimens collected, 35 were S. hominis. The detection of S. hominis bacteria was performed by PCR amplification of two genes FnbA and FnbB and showed 100% and 17.14% of isolates were positive for genes FnbA and FnbB, respectively. The expression of FnbA and FnbB genes was decreased in samples treated with SA compared with untreated ones. In conclusion, there is a significant impact of SA on the prevention of biofilm formation of S. hominis through the suppression of gene expression, specifically FnbA and FnbB. This could enhance susceptibility to antimicrobial treatments. However, more research is required to determine whether SA leads to the selection of resistant bacteria.