The angiotensin II receptors type 1 and 2 modulate astrocytes and their crosstalk with microglia and neurons in an in vitro model of ischemic stroke.

BACKGROUND: Astrocytes are the most abundant cell type of the central nervous system and are fundamentally involved in homeostasis, neuroprotection, and synaptic plasticity. This regulatory function of astrocytes on their neighboring cells in the healthy brain is subject of current research. In the ischemic brain we assume disease specific differences in astrocytic acting. The renin-angiotensin-aldosterone system regulates arterial blood pressure through endothelial cells and perivascular musculature. Moreover, astrocytes express angiotensin II type 1 and 2 receptors. However, their role in astrocytic function has not yet been fully elucidated. We hypothesized that the angiotensin II receptors impact astrocyte function as revealed in an in vitro system mimicking cerebral ischemia. Astrocytes derived from neonatal wistar rats were exposed to telmisartan (angiotensin II type 1 receptor-blocker) or PD123319 (angiotensin II type 2 receptor-blocker) under normal conditions (control) or deprivation from oxygen and glucose. Conditioned medium (CM) of astrocytes was harvested to elucidate astrocyte-mediated indirect effects on microglia and cortical neurons. RESULT: The blockade of angiotensin II type 1 receptor by telmisartan increased the survival of astrocytes during ischemic conditions in vitro without affecting their proliferation rate or disturbing their expression of S100A10, a marker of activation. The inhibition of the angiotensin II type 2 receptor pathway by PD123319 resulted in both increased expression of S100A10 and proliferation rate. The CM of telmisartan-treated astrocytes reduced the expression of pro-inflammatory mediators with simultaneous increase of anti-inflammatory markers in microglia. Increased neuronal activity was observed after treatment of neurons with CM of telmisartan- as well as PD123319-stimulated astrocytes. CONCLUSION: Data show that angiotensin II receptors have functional relevance for astrocytes that differs in healthy and ischemic conditions and effects surrounding microglia and neuronal activity via secretory signals. Above that, this work emphasizes the strong interference of the different cells in the CNS and that targeting astrocytes might serve as a therapeutic strategy to influence the acting of glia-neuronal network in de- and regenerative context.

Combined Insults of a MASH Diet and Alcohol Binges Activate Intercellular Communication and Neutrophil Recruitment via the NLRP3-IL-1ß Axis in the Liver.

Binge drinking in obese patients positively correlates with accelerated liver damage and liver-related death. However, the underlying mechanism and the effect of alcohol use on the progression of metabolic-dysfunction-associated steatotic liver disease (MASLD) remain unexplored. Here, we show that short-term feeding of a metabolic-dysfunction-associated steatohepatitis (MASH) diet plus daily acute alcohol binges for three days induce liver injury and activation of the NLRP3 inflammasome. We identify that a MASH diet plus acute alcohol binges promote liver inflammation via increased infiltration of monocyte-derived macrophages, neutrophil recruitment, and NET release in the liver. Our results suggest that both monocyte-derived macrophages and neutrophils are activated via NLRP3, while the administration of MCC950, an NLRP3 inhibitor, dampens these effects.In this study, we reveal important intercellular communication between hepatocytes and neutrophils. We discover that the MASH diet plus alcohol induces IL-1ß via NLRP3 activation and that IL-1ß acts on hepatocytes and promotes the production of CXCL1 and LCN2. In turn, the increase in these neutrophils recruits chemokines and causes further infiltration and activation of neutrophils in the liver. In vivo administration of the NLRP3 inhibitor, MCC950, improves the early phase of MetALD by preventing liver damage, steatosis, inflammation, and immune cells recruitment.

Macrophages communicate with mesangial cells through the CXCL12/DPP4 axis in lupus nephritis pathogenesis.

Lupus nephritis (LN) occurs in 50% of cases of systemic lupus erythematosus (SLE) and is one of the most serious complications that can occur during lupus progression. Mesangial cells (MCs) are intrinsic cells in the kidney that can regulate capillary blood flow, phagocytose apoptotic cells, and secrete vasoactive substances and growth factors. Previous studies have shown that various types of inflammatory cells can activate MCs for hyperproliferation, leading to disruption of the filtration barrier and impairment of renal function in LN. Here, we characterized the heterogeneity of kidney cells of LN mice by single-nucleus RNA sequencing (snRNA-seq) and revealed the interaction between macrophages and MCs through the CXC motif chemokine ligand 12 (CXCL12)/dipeptidyl peptidase 4 (DPP4) axis. In culture, macrophages modulated the proliferation and migration of MCs through this ligand-receptor interaction. In LN mice, treatment with linagliptin, a DPP4 inhibitor, effectively inhibited MC proliferation and reduced urinary protein levels. Together, our findings indicated that targeting the CXCL12/DPP4 axis with linagliptin treatment may serve as a novel strategy for the treatment of LN via the CXCL12/DPP4 axis.

The diazirine-mediated photo-crosslinking of collagen improves biomaterial mechanical properties and cellular interactions.

In tissue engineering, crosslinking with carbodiimides such as EDC is omnipresent to improve the mechanical properties of biomaterials. However, in collagen biomaterials, EDC reacts with glutamate or aspartate residues, inactivating the binding sites for cellular receptors and rendering collagen inert to many cell types. In this work, we have developed a crosslinking method that ameliorates the rigidity, stability, and degradation rate of collagen biomaterials, whilst retaining key interactions between cells and the native collagen sequence. Our approach relies on the UV-triggered reaction of diazirine groups grafted on lysines, leaving critical amino acid residues intact. Notably, GxxGER recognition motifs for collagen-binding integrins, ablated by EDC crosslinking, were left unreacted, enabling cell attachment, spreading, and colonization on films and porous scaffolds. In addition, our procedure conserves the architecture of biomaterials, improves their resistance to collagenase and cellular contraction, and yields material stiffness akin to that obtained with EDC. Importantly, diazirine-crosslinked collagen can host mesenchymal stem cells, highlighting its strong potential as a substrate for tissue repair. We have therefore established a new crosslinking strategy to modulate the mechanical features of collagen porous scaffolds without altering its biological properties, thereby offering an advantageous alternative to carbodiimide treatment. STATEMENT OF SIGNIFICANCE: This article describes an approach to improve the mechanical properties of collagen porous scaffolds, without impacting collagen's natural interactions with cells. This is significant because collagen crosslinking is overwhelmingly performed using carbodiimides, which results in a critical loss of cellular affinity. By contrast, our method leaves key cellular binding sites in the collagen sequence intact, enabling cell-biomaterial interactions. It relies on the fast, UV-triggered reaction of diazirine with collagen, and does not produce toxic by-products. It also supports the culture of mesenchymal stem cells, a pivotal cell type in a wide range of tissue repair applications. Overall, our approach offers an attractive option for the crosslinking of collagen, a prominent material in the growing field of tissue engineering.

Dictionary of immune responses to cytokines at single-cell resolution.

Cytokines mediate cell-cell communication in the immune system and represent important therapeutic targets1-3. A myriad of studies have highlighted their central role in immune function4-13, yet we lack a global view of the cellular responses of each immune cell type to each cytokine. To address this gap, we created the Immune Dictionary, a compendium of single-cell transcriptomic profiles of more than 17 immune cell types in response to each of 86 cytokines (>1,400 cytokine-cell type combinations) in mouse lymph nodes in vivo. A cytokine-centric view of the dictionary revealed that most cytokines induce highly cell-type-specific responses. For example, the inflammatory cytokine interleukin-1ß induces distinct gene programmes in almost every cell type. A cell-type-centric view of the dictionary identified more than 66 cytokine-driven cellular polarization states across immune cell types, including previously uncharacterized states such as an interleukin-18-induced polyfunctional natural killer cell state. Based on this dictionary, we developed companion software, Immune Response Enrichment Analysis, for assessing cytokine activities and immune cell polarization from gene expression data, and applied it to reveal cytokine networks in tumours following immune checkpoint blockade therapy. Our dictionary generates new hypotheses for cytokine functions, illuminates pleiotropic effects of cytokines, expands our knowledge of activation states of each immune cell type, and provides a framework to deduce the roles of specific cytokines and cell-cell communication networks in any immune response.

2-carba-cyclic phosphatidic acid modulates astrocyte-to-microglia communication and influences microglial polarization towards an anti-inflammatory phenotype.

2-carba-cyclic phosphatidic acid (2ccPA) suppresses microglial and astrocyte inflammation for neuronal survival following traumatic brain injury. However, it remains unknown how 2ccPA regulates microglial activation. In this study, to elucidate the 2ccPA behavior in glial communication, we collected the astrocyte conditioned media (ACM) from primary astrocyte cultures that were treated by lipopolysaccharide (LPS) and 2ccPA and analyzed the alteration of microglial inflammation caused by the ACM treatment. The addition of the ACM derived from LPS- and 2ccPA-double treated astrocytes to microglia decreased the CD86+ pro-inflammatory M1 microglia, which were upregulated with the ACM collected from astrocytes treated by LPS without 2ccPA, while the direct addition of LPS and 2ccPA to microglia failed to decrease the CD86+ microglia to the basal level. We confirmed that the ACM from LPS- and 2ccPA-treated astrocytes increased the ratio of CD206+ anti-inflammatory M2 microglia to total microglia, whereas direct treatment of microglia with LPS and 2ccPA had no effect on the CD206+ microglia ratio, demonstrating the importance of astrocyte intervention in microglial polarization. In addition, we examined whether astrocytes modulate the 2ccPA-regulated proinflammatory cytokine production derived from microglia. The addition of the ACM from LPS- and 2ccPA-treated astrocytes to microglia remarkably canceled the LPS-induced upregulation of IL-1ß, IL-6, and TNF-α secreted from microglia, while the direct addition of LPS and 2ccPA to microglia showed no affect. Therefore, our results indicate that astrocytes mediate the 2ccPA function to shift microglia towards the M2 phenotype by interfering with the polarization of M1 microglia and to suppress cytokine production.

The HDAC inhibitor CI-994 acts as a molecular memory aid by facilitating synaptic and intracellular communication after learning.

Long-term memory formation relies on synaptic plasticity, neuronal activity-dependent gene transcription, and epigenetic modifications. Multiple studies have shown that HDAC inhibitor (HDACi) treatments can enhance individual aspects of these processes and thereby act as putative cognitive enhancers. However, their mode of action is not fully understood. In particular, it is unclear how systemic application of HDACis, which are devoid of substrate specificity, can target pathways that promote memory formation. In this study, we explore the electrophysiological, transcriptional, and epigenetic responses that are induced by CI-994, a class I HDACi, combined with contextual fear conditioning (CFC) in mice. We show that CI-994­mediated improvement of memory formation is accompanied by enhanced long-term potentiation in the hippocampus, a brain region recruited by CFC, but not in the striatum, a brain region not primarily implicated in fear learning. Furthermore, using a combination of bulk and single-cell RNA-sequencing, we find that, when paired with CFC, HDACi treatment engages synaptic plasticity-promoting gene expression more strongly in the hippocampus, specifically in the dentate gyrus (DG). Finally, using chromatin immunoprecipitation-sequencing (ChIP-seq) of DG neurons, we show that the combined action of HDACi application and conditioning is required to elicit enhancer histone acetylation in pathways that underlie improved memory performance. Together, these results indicate that systemic HDACi administration amplifies brain region-specific processes that are naturally induced by learning.

The caspase-1 inhibitor VX765 upregulates connexin 43 expression and improves cell-cell communication after myocardial infarction via suppressing the IL-1ß/p38 MAPK pathway.

Connexin 43 (Cx43) is the most important protein in the gap junction channel between cardiomyocytes. Abnormalities of Cx43 change the conduction velocity and direction of cardiomyocytes, leading to reentry and conduction block of the myocardium, thereby causing arrhythmia. It has been shown that IL-1ß reduces the expression of Cx43 in astrocytes and cardiomyocytes in vitro. However, whether caspase-1 and IL-1ß affect connexin 43 after myocardial infarction (MI) is uncertain. In this study we investigated the effects of VX765, a caspase-1 inhibitor, on the expression of Cx43 and cell-to-cell communication after MI. Rats were treated with VX765 (16 mg/kg, i.v.) 1 h before the left anterior descending artery (LAD) ligation, and then once daily for 7 days. The ischemic heart was collected for histochemical analysis and Western blot analysis. We showed that VX765 treatment significantly decreased the infarct area, and alleviated cardiac dysfunction and remodeling by suppressing the NLRP3 inflammasome/caspase-1/IL-1ß expression in the heart after MI. In addition, VX765 treatment markedly raised Cx43 levels in the heart after MI. In vitro experiments were conducted in rat cardiac myocytes (RCMs) stimulated with the supernatant from LPS/ATP-treated rat cardiac fibroblasts (RCFs). Pretreatment of the RCFs with VX765 (25 µM) reversed the downregulation of Cx43 expression in RCMs and significantly improved intercellular communication detected using a scrape-loading/dye transfer assay. We revealed that VX765 suppressed the activation of p38 MAPK signaling in the heart tissue after MI as well as in RCMs stimulated with the supernatant from LPS/ATP-treated RCFs. Taken together, these data show that the caspase-1 inhibitor VX765 upregulates Cx43 expression and improves cell-to-cell communication in rat heart after MI via suppressing the IL-1ß/p38 MAPK pathway.

Fat3 acts through independent cytoskeletal effectors to coordinate asymmetric cell behaviors during polarized circuit assembly.

The polarized flow of information through neural circuits depends on the orderly arrangement of neurons, their processes, and their synapses. This polarity emerges sequentially in development, starting with the directed migration of neuronal precursors, which subsequently elaborate neurites that form synapses in specific locations. In other organs, Fat cadherins sense the position and then polarize individual cells by inducing localized changes in the cytoskeleton that are coordinated across the tissue. Here, we show that the Fat-related protein Fat3 plays an analogous role during the assembly of polarized circuits in the murine retina. We find that the Fat3 intracellular domain (ICD) binds to cytoskeletal regulators and synaptic proteins, with discrete motifs required for amacrine cell migration and neurite retraction. Moreover, upon ICD deletion, extra neurites form but do not make ectopic synapses, suggesting that Fat3 independently regulates synapse localization. Thus, Fat3 serves as a molecular node to coordinate asymmetric cell behaviors across development.

Resveratrol ameliorates polycystic ovary syndrome via transzonal projections within oocyte-granulosa cell communication.

Rationale: Polycystic ovary syndrome (PCOS) is closely linked to follicular dysplasia and impaired bidirectional oocyte-granulosa cell (GC) communication. Given that PCOS is a heterogeneous, multifactorial endocrine disorder, it is important to clarify the pathophysiology of this ovarian disease and identify a specific treatment. Methods: We generated PCOS rat models based on neonatal tributyltin (TBT) exposure and studied the therapeutic effect and mechanism of resveratrol (RSV), a natural plant polyphenol. Transcriptome analysis was conducted to screen the significantly changed pathways, and a series of experiments, such as quantitative real-time polymerase chain reaction (PCR), Western blot and phalloidin staining, were performed in rat ovaries. We also observed similar changes in human PCOS samples using Gene Expression Omnibus (GEO) database analysis and quantitative real-time PCR. Results: We first found that injury to transzonal projections (TZPs), which are specialized filopodia that mediate oocyte-GC communication in follicles, may play an important role in the etiology of PCOS. We successfully established PCOS rat models using TBT and found that overexpressed calcium-/calmodulin-dependent protein kinase II beta (CaMKIIß) inhibited TZP assembly. In addition, TZP disruption and CAMK2B upregulation were also observed in samples from PCOS patients. Moreover, we demonstrated that RSV potently ameliorated ovarian failure and estrus cycle disorder through TZP recovery via increased cytoplasmic calcium levels and excessive phosphorylation of CaMKIIß. Conclusions: Our data indicated that upregulation of CaMKIIß may play a critical role in regulating TZP assembly and may be involved in the pathogenesis of PCOS associated with ovarian dysfunction. Investigation of TZPs and RSV as potent CaMKIIß activators provides new insight and a therapeutic target for PCOS, which is helpful for improving female reproduction.

Monocytes and pyrophosphate promote mesenchymal stem cell viability and early osteogenic differentiation.

Pyrophosphate-containing calcium phosphate implants promote osteoinduction and bone regeneration. The role of pyrophosphate for inflammatory cell-mesenchymal stem cell (MSC) cross-talk during osteogenesis is not known. In the present work, the effects of lipopolysaccharide (LPS) and pyrophosphate (PPi) on primary human monocytes and on osteogenic gene expression in human adipose-derived MSCs were evaluated in vitro, using conditioned media transfer as well as direct effect systems. Direct exposure to pyrophosphate increased nonadherent monocyte survival (by 120% without LPS and 235% with LPS) and MSC viability (LDH) (by 16-19% with and without LPS). Conditioned media from LPS-primed monocytes significantly upregulated osteogenic genes (ALP and RUNX2) and downregulated adipogenic (PPAR-γ) and chondrogenic (SOX9) genes in recipient MSCs. Moreover, the inclusion of PPi (250 µM) resulted in a 1.2- to 2-fold significant downregulation of SOX9 in the recipient MSCs, irrespective of LPS stimulation or culture media type. These results indicate that conditioned media from LPS-stimulated inflammatory monocytes potentiates the early MSCs commitment towards the osteogenic lineage and that direct pyrophosphate exposure to MSCs can promote their viability and reduce their chondrogenic gene expression. These results are the first to show that pyrophosphate can act as a survival factor for both human MSCs and primary monocytes and can influence the early MSC gene expression. Graphical abstract.

Acute exposure to gold nanoparticles aggravates lipopolysaccharide-induced liver injury by amplifying apoptosis via ROS-mediated macrophage-hepatocyte crosstalk.

BACKGROUND: Gold nanoparticles (AuNPs) are increasingly utilized in industrial and biomedical fields, thereby demanding a more comprehensive knowledge about their safety. Current toxicological studies mainly focus on the unfavorable biological impact governed by the physicochemical properties of AuNPs, yet the consequences of their interplay with other bioactive compounds in biological systems are poorly understood. RESULTS: In this study, AuNPs with a size of 10 nm, the most favorable size for interaction with host cells, were given alone or in combination with bacterial lipopolysaccharide (LPS) in mice or cultured hepatic cells. The results demonstrated that co exposure to AuNPs and LPS exacerbated fatal acute liver injury (ALI) in mice, although AuNPs are apparently non-toxic when administered alone. AuNPs do not enhance systemic or hepatic inflammation but synergize with LPS to upregulate hepatic apoptosis by augmenting macrophage-hepatocyte crosstalk. Mechanistically, AuNPs and LPS coordinate to upregulate NADPH oxidase 2 (NOX2)-dependent reactive oxygen species (ROS) generation and activate the intrinsic apoptotic pathway in hepatic macrophages. Extracellular ROS generation from macrophages is then augmented, thereby inducing calcium-dependent ROS generation and promoting apoptosis in hepatocytes. Furthermore, AuNPs and LPS upregulate scavenger receptor A expression in macrophages and thus increase AuNP uptake to mediate further apoptosis induction. CONCLUSIONS: This study reveals a profound impact of AuNPs in aggravating the hepatotoxic effect of LPS by amplifying ROS-dependent crosstalk in hepatic macrophages and hepatocytes.

Inhibition of transcription factor NFAT activity in activated platelets enhances their aggregation and exacerbates gram-negative bacterial septicemia.

During gram-negative septicemia, interactions between platelets and neutrophils initiate a detrimental feedback loop that sustains neutrophil extracellular trap (NET) induction, disseminated intravascular coagulation, and inflammation. Understanding intracellular pathways that control platelet-neutrophil interactions is essential for identifying new therapeutic targets. Here, we found that thrombin signaling induced activation of the transcription factor NFAT in platelets. Using genetic and pharmacologic approaches, as well as iNFATuation, a newly developed mouse model in which NFAT activation can be abrogated in a cell-specific manner, we demonstrated that NFAT inhibition in activated murine and human platelets enhanced their activation and aggregation, as well as their interactions with neutrophils and NET induction. During gram-negative septicemia, NFAT inhibition in platelets promoted disease severity by increasing disseminated coagulation and NETosis. NFAT inhibition also partially restored coagulation ex vivo in patients with hypoactive platelets. Our results define non-transcriptional roles for NFAT that could be harnessed to address pressing clinical needs.

The PqsE-RhlR Interaction Regulates RhlR DNA Binding to Control Virulence Factor Production in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an opportunistic pathogen that causes disease in immunocompromised individuals and individuals with underlying pulmonary disorders. P. aeruginosa virulence is controlled by quorum sensing (QS), a bacterial cell-cell communication mechanism that underpins transitions between individual and group behaviors. In P. aeruginosa, the PqsE enzyme and the QS receptor RhlR directly interact to control the expression of genes involved in virulence. Here, we show that three surface-exposed arginine residues on PqsE comprise the site required for interaction with RhlR. We show that a noninteracting PqsE variant [PqsE(NI)] possesses catalytic activity, but is incapable of promoting virulence phenotypes, indicating that interaction with RhlR, and not catalysis, drives these PqsE-dependent behaviors. Biochemical characterization of the PqsE-RhlR interaction coupled with RNA-seq analyses demonstrates that the PqsE-RhlR complex increases the affinity of RhlR for DNA, enabling enhanced expression of genes encoding key virulence factors. These findings provide the mechanism for PqsE-dependent regulation of RhlR and identify a unique regulatory feature of P. aeruginosa QS and its connection to virulence. IMPORTANCE Bacteria use a cell-cell communication process called quorum sensing (QS) to orchestrate collective behaviors. QS relies on the group-wide detection of molecules called autoinducers (AI). QS is required for virulence in the human pathogen Pseudomonas aeruginosa, which can cause fatal infections in patients with underlying pulmonary disorders. In this study, we determine the molecular basis for the physical interaction between two virulence-driving QS components, PqsE and RhlR. We find that the ability of PqsE to bind RhlR correlates with virulence factor production. Since current antimicrobial therapies exacerbate the growing antibiotic resistance problem because they target bacterial growth, we suggest that the PqsE-RhlR interface discovered here represents a new candidate for targeting with small molecule inhibition. Therapeutics that disrupt the PqsE-RhlR interaction should suppress virulence. Targeting bacterial behaviors such as QS, rather than bacterial growth, represents an attractive alternative for exploration because such therapies could potentially minimize the development of resistance.

ICAM-1-mediated adhesion is a prerequisite for exosome-induced T cell suppression.

Tumor-derived extracellular vesicles (TEVs) suppress the proliferation and cytotoxicity of CD8+ T cells, thereby contributing to tumor immune evasion. Here, we report that the adhesion molecule intercellular adhesion molecule 1 (ICAM-1) co-localizes with programmed death ligand 1 (PD-L1) on the exosomes; both ICAM-1 and PD-L1 are upregulated by interferon-γ. Exosomal ICAM-1 interacts with LFA-1, which is upregulated in activated T cells. Blocking ICAM-1 on TEVs reduces the interaction of TEVs with CD8+ T cells and attenuates PD-L1-mediated suppressive effects of TEVs. During this study, we have established an extracellular vesicle-target cell interaction detection through SorTagging (ETIDS) system to assess the interaction between a TEV ligand and its target cell receptor. Using this system, we demonstrate that the interaction of TEV PD-L1 with programmed cell death 1 (PD-1) on T cells is significantly reduced in the absence of ICAM-1. Our study demonstrates that ICAM-1-LFA-1-mediated adhesion between TEVs and T cells is a prerequisite for exosomal PD-L1-mediated immune suppression.

Repeated Social Defeat Exaggerates Fibrin-Rich Clot Formation by Enhancing Neutrophil Extracellular Trap Formation via Platelet-Neutrophil Interactions.

Depression is an independent risk factor for cardiovascular disease (CVD). We have previously shown that repeated social defeat (RSD) exaggerates atherosclerosis development by enhancing neutrophil extracellular trap (NET) formation. In this study, we investigated the impact of RSD on arterial thrombosis. Eight-week-old male wild-type mice (C57BL/6J) were exposed to RSD by housing with larger CD-1 mice in a shared home cage. They were subjected to vigorous physical contact daily for 10 consecutive days. After confirming depression-like behaviors, mice underwent FeCl3-induced carotid arterial injury and were analyzed after 3 h. Although the volume of thrombi was comparable between the two groups, fibrin(ogen)-positive areas were significantly increased in defeated mice, in which Ly-6G-positive cells were appreciably co-localized with Cit-H3-positive staining. Treatment with DNase I completely diminished exaggerated fibrin-rich clot formation in defeated mice. Flow cytometric analysis showed that neutrophil CD11b expression before FeCl3 application was significantly higher in defeated mice than in control mice. In vitro NET formation induced by activated platelets was significantly augmented in defeated mice, which was substantially inhibited by anti-CD11b antibody treatment. Our findings demonstrate that RSD enhances fibrin-rich clot formation after arterial injury by enhancing NET formation, suggesting that NET can be a new therapeutic target in depression-related CVD.

Lipid-induced S-palmitoylation as a Vital Regulator of Cell Signaling and Disease Development.

Lipid metabolites are emerging as pivotal regulators of protein function and cell signaling. The availability of intracellular fatty acid is tightly regulated by glycolipid metabolism and may affect human body through many biological mechanisms. Recent studies have demonstrated palmitate, either from exogenous fatty acid uptake or de novo fatty acid synthesis, may serve as the substrate for protein palmitoylation and regulate protein function via palmitoylation. Palmitoylation, the most-studied protein lipidation, encompasses the reversible covalent attachment of palmitate moieties to protein cysteine residues. It controls various cellular physiological processes and alters protein stability, conformation, localization, membrane association and interaction with other effectors. Dysregulation of palmitoylation has been implicated in a plethora of diseases, such as metabolic syndrome, cancers, neurological disorders and infections. Accordingly, it could be one of the molecular mechanisms underlying the impact of palmitate metabolite on cellular homeostasis and human diseases. Herein, we explore the relationship between lipid metabolites and the regulation of protein function through palmitoylation. We review the current progress made on the putative role of palmitate in altering the palmitoylation of key proteins and thus contributing to the pathogenesis of various diseases, among which we focus on metabolic disorders, cancers, inflammation and infections, neurodegenerative diseases. We also highlight the opportunities and new therapeutics to target palmitoylation in disease development.

Novel Xanthone Derivatives Impair Growth and Invasiveness of Colon Cancer Cells In Vitro.

Natural xanthones are a large group of compounds from which promising anticancer properties could be further developed by chemical modifications. This study aimed to investigate the influence of four novel xanthone derivatives based on a naturally occurring xanthone skeleton on the invasiveness of colon cancer cells in vitro. First, the concentrations required to inhibit growth of three colorectal cancer cell lines to 50% (GI50) of all the studied compounds, as well as the natural xanthones used as a reference (gambogic acid and α-mangostin), have been established (MTS reduction test). Next, the assays determining several aspects of the GI25 xanthones influence on colorectal cancer cells, including cytotoxicity, migration and invasion potential, interaction with extracellular matrix and endothelial cells, as well as expression of selected invasiveness related genes have been performed. Our results demonstrate that these novel xanthone derivatives impair colorectal cancer proliferation, motility, adhesion to extracellular matrix and to endothelial cells, and also induce apoptosis and cell death. Moreover, their activity is comparable to cisplatin and 5-fluorouracil, used as reference compounds. Conducted research indicates our compounds for further research and development as novel drugs in colorectal cancer treatment.

Cellular crosstalk regulates the aqueous humor outflow pathway and provides new targets for glaucoma therapies.

Primary congenital glaucoma (PCG) is a severe disease characterized by developmental defects in the trabecular meshwork (TM) and Schlemm's canal (SC), comprising the conventional aqueous humor outflow pathway of the eye. Recently, heterozygous loss of function variants in TEK and ANGPT1 or compound variants in TEK/SVEP1 were identified in children with PCG. Moreover, common variants in ANGPT1and SVEP1 have been identified as risk alleles for primary open angle glaucoma (POAG) in GWAS studies. Here, we show tissue-specific deletion of Angpt1 or Svep1 from the TM causes PCG in mice with severe defects in the adjacent SC. Single-cell transcriptomic analysis of normal and glaucomatous Angpt1 deficient eyes allowed us to identify distinct TM and SC cell populations and discover additional TM-SC signaling pathways. Furthermore, confirming the importance of angiopoietin signaling in SC, delivery of a recombinant ANGPT1-mimetic promotes developmental SC expansion in healthy and Angpt1 deficient eyes, blunts intraocular pressure (IOP) elevation and RGC loss in a mouse model of PCG and lowers IOP in healthy adult mice. Our data highlight the central role of ANGPT1-TEK signaling and TM-SC crosstalk in IOP homeostasis and provide new candidates for SC-targeted glaucoma therapy.

In Silico Evaluation of Natural Compounds for an Acidic Extracellular Environment in Human Breast Cancer.

The survival rates for breast cancer (BC) have improved in recent years, but resistance, metastasis, and recurrence still remain major therapeutic challenges for BC. The acidic tumor microenvironment (TME) has attracted attention because of its association with tumorigenesis, metastasis, drug resistance, and immune surveillance. In this study, we evaluated natural compounds from traditional herbal medicine used to treat cancer that selectively target genes regulated by extracellular acidosis. We integrated four transcriptomic data including BC prognostic data from The Cancer Genome Atlas database, gene expression profiles of MCF-7 cells treated with 102 natural compounds, patterns of gene profiles by acidic condition, and single-cell RNA-sequencing from BC patient samples. Bruceine D (BD) was predicted as having the highest therapeutic potential, having an information gain (IG) score of 0.24, to regulate reprogrammed genes driven by acidosis affecting the survival of BC patients. BD showed the highest IG on EMT (IG score: 0.11) and invasion (IG score: 0.1) compared to the other phenotypes with the CancerSEA database. BD also demonstrated therapeutic potential by interfering with the tumor cell-TME interactions by reducing the amyloid beta precursor protein and CD44 expression. Therefore, BD is a potential candidate to target the acidic TME induced metastatic process in BC.