Rap1: a key regulator in cell-cell junction formation

Single-cell and spatial transcriptome analyses reveal tumor heterogeneity and immune remodeling involved in pituitary neuroendocrine tumor progression

Pituitary neuroendocrine tumors (PitNETs) can be invasive or aggressive, yet the mechanisms behind these behaviors remain poorly understood, impeding treatment advancements. Here, we integrat single-cell RNA sequencing and spatial transcriptomics, analyzing over 177,000 cells and 35,000 spots across 57 tissue samples. This comprehensive approach facilitates the identification of PitNETs tumor populations and characterizes the reconfiguration of the tumor microenvironment (TME) as PitNETs progress and invade. We trace the trajectory of TPIT-lineage PitNETs and identify an aggressive tumor cluster marked by elevated p53-mediated proliferation and a higher Trouillas classification, both associated with tumor progression. Additionally, we document the heterogeneity of immune stromal cells within PitNETs, particularly noting the enrichment of SPP1+ tumor associated macrophages (TAMs) in invasive tumors. These TAMs facilitate tumor invasion through the SPP1-ITGAV/ITGB1 signaling pathway. Our in-depth single-cell and spatial analysis of PitNETs uncovers the molecular dynamics within the TME, suggesting potential targets for therapeutic intervention.

Decoding the Nectin Interactome: Implications for Brain Development, Plasticity, and Neurological Disorders

The nectin family of cell adhesion molecules (CAMs) comprising nectins and nectin-like molecules has emerged as a key regulator of various pivotal neural processes, including neuronal development, migration, synapse formation, and plasticity. Nectins engage in homophilic and heterophilic interactions to mediate cell-cell adhesion, contributing to the establishment and maintenance of neural circuits. Their extracellular domains facilitate trans-synaptic interactions, while intracellular domains participate in signaling cascades influencing cytoskeletal dynamics and synaptic function. The exhibition of distinct localization patterns in neurons, astrocytes, and the blood-brain barrier underscores their diverse roles in the brain. The dysregulation of nectins has been implicated in several neurological disorders, such as neurodevelopmental disorders, depression, schizophrenia, and Alzheimer's disease. This review examines the structural and functional characteristics of nectins and their distribution and molecular mechanisms governing neural connectivity and cognition. It further discusses experimental studies unraveling nectin-mediated pathophysiology and potential therapeutic interventions targeting nectin-related pathways. Collectively, this comprehensive analysis highlights the significance of nectins in brain development, function, and disorders, paving the way for future research directions and clinical implications.

tRF-5028c disrupts trophoblast function in recurrent spontaneous abortion by inhibiting CRKL-mediated Rap1 signaling pathway

BACKGROUND

Recurrent spontaneous abortion (RSA) affects approximately 1-5% of childbearing women and poses a significant threat to global reproductive health. Transfer RNA-derived small RNAs (tsRNAs) are a novel class of noncoding RNAs implicated in various human diseases. However, the role and mechanism of tsRNAs in regulating trophoblast function during RSA development remain unknown.

METHODS

High-throughput sequencing was performed to analyze the differential tsRNAs in the villous tissues of patients with RSA and controls. CCK-8, transwell assay, and flow cytometry were performed to detect the effects of tRF-5028c on proliferation, migration, invasion, and apoptosis of human extravillous trophoblast cell line HTR-8/SVneo. The target genes of tRF-5028c were predicted via bioinformatic analysis and verified by dual luciferase reporter gene assay. Moreover, pregnant mice were injected with tRF-5028c mimics to confirm the findings in vivo.

RESULTS

A total of 1907 tsRNAs were detected, of which 298 were differentially expressed in the villous tissues. tRF-5028c was significantly upregulated in the RSA group compared with control. Functionally, tRF-5028c overexpression inhibited HTR-8/SVneo cell proliferation, migration, and invasion and promoted apoptosis, whereas tRF-5028c knockdown showed opposite effects. Mechanically, tRF-5028c suppressed CRKL expression by directly binding to its 3'-untranslated region, thus inactivating the downstream C3G/Rap1 signaling pathway. Finally, tRF-5028c mimics injection increased embryo absorption rate in mice.

CONCLUSIONS

tRF-5028c upregulation impaired trophoblast function to facilitate RSA development by directly targeting CRKL-mediated Rap1 pathway. The findings provide the first evidence of tsRNA dysregulation in RSA pathogenesis and lay a foundation for potential targeted therapies.

Invasion of glioma cells through confined space requires membrane tension regulation and mechano-electrical coupling via Plexin-B2

Glioblastoma (GBM) is a malignant brain tumor with diffuse infiltration. Here, we demonstrate how GBM cells usurp guidance receptor Plexin-B2 for confined migration through restricted space. Using live-cell imaging to track GBM cells negotiating microchannels, we reveal endocytic vesicle accumulation at cell front and filamentous actin assembly at cell rear in a polarized manner. These processes are interconnected and require Plexin-B2 signaling. We further show that Plexin-B2 governs membrane tension and other membrane features such as endocytosis, phospholipid composition, and inner leaflet surface charge, thus providing biophysical mechanisms by which Plexin-B2 promotes GBM invasion. Together, our studies unveil how GBM cells regulate membrane tension and mechano-electrical coupling to adapt to physical constraints and achieve polarized confined migration.

Down-regulation of TAGLN2 associated with the development of preeclampsia by effecting the Rap1 signaling pathway

INTRODUCTION

Preeclampsia (PE) poses significant global challenges to pregnancy health, being a leading cause of maternal and perinatal morbidity and mortality. Unfortunately, effective treatment options remain limited, necessitating the urgent development of novel therapeutic strategies. This study is to investigate down-regulation of Transgelin-2 (TAGLN2) contributes to the development of PE through suppression of the Rap1 signaling pathway.

METHODS

Placentas from PE patients were collected for a transcriptome analysis. Down-regulation experiments of TAGLN2 were performed in mouse and HTR-8/SVneo cells to generate PE models. The mechanism by which down-regulation of TAGLN2 induces PE was explored based on these PE model through transcriptome and proteome analysis and molecular tests.

RESULTS

Our findings revealed that the expression levels of Rap1A was significantly reduced in the placenta of PE patients. The expression level of Rap1A in the placental tissue of sh_Tagln2 PE model mice is down-regulated. In addition, TAGLN2 down-regulation impede the proliferation and migration of HTR8/SVneo cells and lead to the decreased expression of Rap1A. Meanwhile, Rap1A down-regulation impede both the proliferation and migration of HTR8/SVneo cells. Both transcriptomic and proteomic levels of sh-TG2 HTR8/SVneo cells demonstrated Rap1 signaling pathway and related key genes was inhibited after TAGLN2 down-regulation.

CONCLUSION

Our results confirm that down-regulation of TAGLN2 in HTR-8/SVneo cells leads to the decreased Rap1A expression and suppresses trophoblast cell proliferation and migration by inhibiting Rap1 signaling pathway. Meanwhile, Rap1A down-regulation impede both the proliferation and migration of HTR8/SVneo cells. These findings concluded that down-regulation of TAGLN2 may be implicated in the development of preeclampsia through its effect on the Rap1 signaling pathway.

MicroRNA expression profiles in plasma exosomes of late pregnant giant pandas

BACKGROUND

MicroRNAs can regulate various biological functions including cell proliferation, differentiation, embryo formation, and implantation. The giant panda exhibits embryonic diapause, with embryo development resuming in late pregnancy. However, the changes in microRNAs during late pregnancy remain poorly understand.

METHODS AND RESULTS

After mating, plasma samples were collected on day 40 of early pregnancy (EP; n = 3) and 30 days before delivery of late pregnancy (LP; n = 3). Following microRNAs screening, a total of 120 microRNAs were detected in the plasma exosomes of pregnant pandas. Nine differentially expressed microRNAs (DEmicroRNAs) were identified in LP compared to EP, including three that were upregulated and six that were downregulated. Notably, miR-25b and miR-47 were significantly downregulated in LP group. All DEmicroRNAs were predicted to target a total of 2,675 genes. Pathway enrichment analysis of these target genes revealed significant enrichment in the MAPK and Rap1 signaling pathways, which are closely related to cell proliferation, differentiation, and cell-cell and cell-matrix interactions. Analysis of protein-protein interaction networks showed that most of the hub genes (five out of eight), including Fgfr1, Fgf2, Fgf18, Erbb4, and Kras within the MAPK and Rap1 pathways are associated with the cell proliferation and differentiation. Significantly, Erbb4 was regulated by significantly differentially expressed miRNA-47.

CONCLUSIONS

We suggest that plasma exosomal microRNAs are involved in cell proliferation and differentiation during embryonic development by regulating key hub genes within MAPK and Rap1 pathways. These findings provided new insights into the development of giant panda embryos.

Comparative transcriptomic analysis of hepatopancreas reveals that more genes are involved in the exposure response of Vibrio parahaemolyticus PirAvp compared to PirBvp

Vibrio parahaemolyticus (VP-AHPND) is regarded as one of the main pathogens that caused acute hepatopancreatic necrosis disease (AHPND) in the Pacific white shrimp Litopenaeus vannamei. PirAvp and PirBvp toxin proteins are the main pathogenic proteins of AHPND in shrimp. Knowledge about the mechanism of shrimp response to PirAvp or PirBvp toxin is very helpful for developing new prevention and control strategy of AHPND in shrimp. In this study, the pathological sections showed that after 4 h treatment, significant pathological changes were observed in the PirBvp treated group, and no obvious pathological changes was found in PirAvp treated group. In order to learn the mechanism of shrimp response to PirAvp and PirBvp, comparative transcriptome was applied to analyze the different expressions of genes in the hepatopancreas of shrimp after treatment with PirAvp or PirBvp. A total of 9978 differentially expressed genes (DEGs) were identified between PirAvp or PirBvp-treated and PBS control shrimp, including 6616 DEGs in the PirAvp treated group and 3362 DEGs in the PirBvp treated group. There were 2263 DEGs that were commonly expressed, 4353 DEGs were only expressed in PirAvp VS PBS group and 1099 DEGs were uniquely expressed in PirBvp VS PBS group. Among these DEGs, the anti-apoptosis related pathways and immune response related genes significantly expressed in the commonly expressed DEGs of PirAvp VS PBS group and PirBvp VS PBS group, and small GTPase-mediated signaling and DNA metabolic process might relate to the host special reaction towards PirAvp and PirBvp exposure. The data suggested that the differential expression of these immune and metabolic-related genes in hepatopancreas might contribute to the pathogenicity variations of shrimp to VP-AHPND. The identified genes in this study will be useful for clarifying the response mechanism of shrimp toward different toxins of VP-AHPND and will further provide molecular basis for understanding the pathogenic mechanism of VP-AHPND.

RAP1-GTPase immunostaining is altered in human precancerous and cancerous cervical lesions

Aim: This study investigated RAP1 immunostaining variation in different cell types during CC progression.Methods: Paraffin-embedded cervical tissues from 101 patients were categorized into control, pre-neoplastic and neoplastic groups. RAP1 immunolocalization, HPV detection and genotyping were performed. A semiquantitative immunoreactive score was employed to compare labeling intensity, cellular localization, nuclear labeling, percentage and distribution of reactive cells.Results: 73% (72/99) of cervical specimens were HPV+. RAP1 was localized in the nucleus and cytoplasm of all samples. Cytoplasmic RAP1 immunoscore was higher than nuclear score in all CC groups. RAP1 intensity increased with lesion severity. SCC samples exhibited predominantly intense RAP1 immunostaining.Conclusion: RAP1 is an efficient biomarker for detecting invasive CC lesions but has limited utility in distinguishing SCC grades.

NIR-activated electrospun nanodetonator dressing enhances infected diabetic wound healing with combined photothermal and nitric oxide-based gas therapy

Diabetic wounds pose a challenge to healing due to increased bacterial susceptibility and poor vascularization. Effective healing requires simultaneous bacterial and biofilm elimination and angiogenesis stimulation. In this study, we incorporated polyaniline (PANI) and S-Nitrosoglutathione (GSNO) into a polyvinyl alcohol, chitosan, and hydroxypropyltrimethyl ammonium chloride chitosan (PVA/CS/HTCC) matrix, creating a versatile wound dressing membrane through electrospinning. The dressing combines the advantages of photothermal antibacterial therapy and nitric oxide gas therapy, exhibiting enduring and effective bactericidal activity and biofilm disruption against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. Furthermore, the membrane's PTT effect and NO release exhibit significant synergistic activation, enabling a nanodetonator-like burst release of NO through NIR irradiation to disintegrate biofilms. Importantly, the nanofiber sustained a uniform release of nitric oxide, thereby catalyzing angiogenesis and advancing cellular migration. Ultimately, the employment of this membrane dressing culminated in the efficacious amelioration of diabetic-infected wounds in Sprague-Dawley rats, achieving wound closure within a concise duration of 14 days. Upon applying NIR irradiation to the PVA-CS-HTCC-PANI-GSNO nanofiber membrane, it swiftly eradicates bacteria and biofilm within 5 min, enhancing its inherent antibacterial and anti-biofilm properties through the powerful synergistic action of PTT and NO therapy. It also promotes angiogenesis, exhibits excellent biocompatibility, and is easy to use, highlighting its potential in treating diabetic wounds.

EspP2 Regulates the Adhesion of Glaesserella parasuis via Rap1 Signaling Pathway

Different levels of EspP2 expression are seen in strains of Glaesserella parasuis with high and low pathogenicity. As a potential virulence factor for G. parasuis, the pathogenic mechanism of EspP2 in infection of host cells is not clear. To begin to elucidate the effect of EspP2 on virulence, we used G. parasuis SC1401 in its wild-type form and SC1401, which was made EspP2-deficient. We demonstrated that EspP2 causes up-regulation of claudin-1 and occludin expression, thereby promoting the adhesion of G. parasuis to host cells; EspP2-deficiency resulted in significantly reduced adhesion of G. parasuis to cells. Transcriptome sequencing analysis of EspP2-treated PK15 cells revealed that the Rap1 signaling pathway is stimulated by EspP2. Blocking this pathway diminished occludin expression and adhesion. These results indicated that EspP2 regulates the adhesion of Glaesserella parasuis via Rap1 signaling pathway.

PROS1 is a crucial gene in the macrophage efferocytosis of diabetic foot ulcers: a concerted analytical approach through the prisms of computer analysis

BACKGROUND

Diabetic foot ulcers (DFUs) pose a serious long-term threat because of elevated mortality and disability risks. Research on its biomarkers is still, however, very limited. In this paper, we have effectively identified biomarkers linked with macrophage excretion in diabetic foot ulcers through the application of bioinformatics and machine learning methodologies. These findings were subsequently validated using external datasets and animal experiments. Such discoveries are anticipated to offer novel insights and approaches for the early diagnosis and treatment of DFU.

METHODS

In this work, we used the Gene Expression Omnibus (GEO) database's datasets GSE68183 and GSE80178 as the training dataset to build a gene model using machine learning methods. After that, we used the training and validation sets to validate the model (GSE134431). On the model genes, we performed enrichment analysis using both gene set variant analysis (GSVA) and gene set enrichment analysis (GSEA). Additionally, the model genes were subjected to immunological association and immune function analyses.

RESULTS

In this study, PROS1 was identified as a potential key target associated with macrophage efflux in DFU by machine learning and bioinformatics approaches. Subsequently, the key biomarker status of PROS1 in DFU was also confirmed by external datasets. In addition, PROS1 also plays a key role in macrophage exudation in DFU. This gene may be associated with macrophage M1, CD4 memory T cells, naïve B cells, and macrophage M2, and affects IL-17, Rap1, hedgehog, and JAK-STAT signaling pathways.

CONCLUSIONS

PROS1 was identified and validated as a biomarker for DFU. This finding has the potential to provide a target for macrophage clearance of DFU.

Ras3 in Bombyx mori with antiviral function against B. mori nucleopolyhedrovirus

Bombyx mori ras protein3 (BmRas3) is a small molecular protein in the GTPase superfamily, which has the activity of binding guanosine nucleotides and GTP enzymes. It acts as a molecular switch by coupling extracellular signal to different cellular response through the conversion between Ras-GTP conformation and Ras-GDP conformation, thus regulating signal pathways responsible for cell growth, migration, adhesion, survival and differentiation. However, few studies have been done on Ras3 in silkworm, and its function and mechanism are unclear. In this study, we found that the overexpression of BmRas3 inhibited the infection of BmNPV(B. mori nucleopolyhedrovirus), while knockdown of BmRas3 could promote the infection of BmNPV. In addition, after the BmRas3 in silkworm larvae was knockdown, the anti-BmNPV ability of silkworm decreased and the survival rate of silkworm was affected. Additionly in the cells with BmRas3 overexpression, the transcription level of BmMapkk6 、BmP38、BmJNK、BmERK1/2 and BmERK5 were significantly increased after BmNPV infection, and the transcript levels of BmMapkk6、BmP38、BmJNK、BmERK1/2 and BmERK5 were also inhibited to varying degrees This is the first report on the antiviral effect of BmRas3 in silkworm, which provides a new direction for further study on the anti-BmNPV mechanism of silkworm and screening and cultivation of anti-BmNPV silkworm strain.

Intellectual disability syndrome associated with a homozygous founder variant in SGSM3 in Ashkenazi Jews

BACKGROUND

Neurodevelopmental disorders (NDDs) impact both the development and functioning of the brain and exhibit clinical and genetic variability. RAP and RAB proteins, belonging to the RAS superfamily, are identified as established contributors to NDDs. However, the involvement of SGSM (small G protein signalling modulator), another member of the RAS family, in NDDs has not been previously documented.

METHODS

Proband-only or trio exome sequencing was performed on DNA samples obtained from affected individuals and available family members. The variant prioritisation process focused on identifying rare deleterious variants. International collaboration aided in the identification of additional affected individuals.

RESULTS

We identified 13 patients from 8 families of Ashkenazi Jewish origin who all carried the same homozygous frameshift variant in SGSM3 gene. The variant was predicted to cause a loss of function, potentially leading to impaired protein structure or function. The variant co-segregated with the disease in all available family members. The affected individuals displayed mild global developmental delay and mild to moderate intellectual disability. Additional prevalent phenotypes observed included hypotonia, behavioural challenges and short stature.

CONCLUSIONS

An Ashkenazi Jewish homozygous founder variant in SGSM3 was discovered in individuals with NDDs and short stature. This finding establishes a connection between another member of the RAS family and NDDs. Additional research is needed to uncover the specific molecular mechanisms by which SGSM3 influences neurodevelopmental processes and the regulation of growth.

Proteomic Analysis Reveals the Effects of Different Dietary Protein Levels on Growth and Development of Jersey-Yak

Jersey-yak is a hybrid offspring of Jersey cattle and yak (Bos grunniens). Changing the feeding system of Jersey-yak can significantly improve its growth performance. In this study, tandem mass tag (TMT) proteomics technology was used to determine the differentially expressed proteins (DEPs) of the longissimus lumborum (LL) muscle of Jersey-yak fed different protein levels of diet. The results showed that compared with the traditional grazing feeding, the growth performance of Jersey-yaks was significantly improved by crude protein supplementation after grazing. A total of 3368 proteins were detected in these muscle samples, of which 3365 were quantified. A total of 434 DEPs were identified. Through analyses, it was found that some pathways related to muscle growth and development were significantly enriched, such as Rap1 signaling pathway, mTOR signaling pathway, and TGF-beta signaling pathway. A number of DEPs enriched in these pathways are related to muscle cell development, differentiation, and muscle development, including integrin subunit alpha 7 (ITGA7), myosin heavy chain 8 (MYH8), and collagen type XII alpha 1 chain (COL12A1). In conclusion, the results of this study provide insights into the proteomics of different feeding patterns of Jersey-yak, providing a stronger basis for further understanding the biological mechanism of hybrid varieties.

Invasion of glioma cells through confined space requires membrane tension regulation and mechano-electrical coupling via Plexin-B2

Glioblastoma (GBM) is a malignant brain tumor with uncontrolled invasive growth. Here, we demonstrate how GBM cells usurp guidance receptor Plexin-B2 to gain biomechanical plasticity for polarized migration through confined space. Using live-cell imaging to track GBM cells negotiating microchannels, we reveal active endocytosis at cell front and filamentous actin assembly at rear to propel GBM cells through constrictions. These two processes are interconnected and governed by Plexin-B2 that orchestrates cortical actin and membrane tension, shown by biomechanical assays. Molecular dynamics simulations predict that balanced membrane and actin tension are required for optimal migratory velocity and consistency. Furthermore, Plexin-B2 mechanosensitive function requires a bendable extracellular ring structure and affects membrane internalization, permeability, phospholipid composition, as well as inner membrane surface charge. Together, our studies unveil a key element of membrane tension and mechanoelectrical coupling via Plexin-B2 that enables GBM cells to adapt to physical constraints and achieve polarized confined migration.

Syndapin and GTPase RAP-1 control endocytic recycling via RHO-1 and non-muscle myosin II

After endocytosis, many plasma membrane components are recycled via membrane tubules that emerge from early endosomes to form recycling endosomes, eventually leading to their return to the plasma membrane. We previously showed that Syndapin/PACSIN-family protein SDPN-1 is required in vivo for basolateral endocytic recycling in the C. elegans intestine. Here, we document an interaction between the SDPN-1 SH3 domain and a target sequence in PXF-1/PDZ-GEF1/RAPGEF2, a known exchange factor for Rap-GTPases. We found that endogenous mutations engineered into the SDPN-1 SH3 domain, or its binding site in the PXF-1 protein, interfere with recycling in vivo, as does the loss of the PXF-1 target RAP-1. In some contexts, Rap-GTPases negatively regulate RhoA activity, suggesting a potential for Syndapin to regulate RhoA. Our results indicate that in the C. elegans intestine, RHO-1/RhoA is enriched on SDPN-1- and RAP-1-positive endosomes, and the loss of SDPN-1 or RAP-1 elevates RHO-1(GTP) levels on intestinal endosomes. Furthermore, we found that depletion of RHO-1 suppressed sdpn-1 mutant recycling defects, indicating that control of RHO-1 activity is a key mechanism by which SDPN-1 acts to promote endocytic recycling. RHO-1/RhoA is well known for controlling actomyosin contraction cycles, although little is known about the effects of non-muscle myosin II on endosomes. Our analysis found that non-muscle myosin II is enriched on SDPN-1-positive endosomes, with two non-muscle myosin II heavy-chain isoforms acting in apparent opposition. Depletion of nmy-2 inhibited recycling like sdpn-1 mutants, whereas depletion of nmy-1 suppressed sdpn-1 mutant recycling defects, indicating that actomyosin contractility controls recycling endosome function.

Revealing Tissue Heterogeneity and Spatial Dark Genes from Spatially Resolved Transcriptomics by Multiview Graph Networks

Spatially resolved transcriptomics (SRT) is capable of comprehensively characterizing gene expression patterns and providing an unbiased image of spatial composition. To fully understand the organizational complexity and tumor immune escape mechanism, we propose stMGATF, a multiview graph attention fusion model that integrates gene expression, histological images, spatial location, and gene association. To better extract information, stMGATF exploits SimCLRv2 for visual feature exaction and employs edge feature enhanced graph attention networks for the learning potential embedding of each view. A global attention mechanism is used to adaptively integrate 3 views to obtain low-dimensional representation. Applied to diverse SRT datasets, stMGATF is robust and outperforms other methods in detecting spatial domains and denoising data even with different resolutions and platforms. In particular, stMGATF contributes to the elucidation of tissue heterogeneity and extraction of 3-dimensional expression domains. Importantly, considering the associations between genes in tumors, stMGATF can identify the spatial dark genes ignored by traditional methods, which can be used to predict tumor-driving transcription factors and reveal tumor immune escape mechanisms, providing theoretical evidence for the development of new immunotherapeutic strategies.

Chromosome-level Dinobdella ferox genome provided a molecular model for its specific parasitism

BACKGROUND

Dinobdella ferox is the most frequently reported leech species parasitizing the mammalian nasal cavity. However, the molecular mechanism of this special parasitic behavior has remained largely unknown.

METHODS

PacBio long-read sequencing, next-generation sequencing (NGS), and Hi-C sequencing were employed in this study to generate a novel genome of D. ferox, which was annotated with strong certainty using bioinformatics methods. The phylogenetic and genomic alterations of D. ferox were then studied extensively alongside the genomes of other closely related species. The obligatory parasitism mechanism of D. ferox was investigated using RNA-seq and proteomics data.

RESULTS

PacBio long-read sequencing and NGS yielded an assembly of 228 Mb and contig N50 of 2.16 Mb. Along Hi-C sequencing, 96% of the sequences were anchored to nine linkage groups and a high-quality chromosome-level genome was generated. The completed genome included 19,242 protein-coding genes. For elucidating the molecular mechanism of nasal parasitism, transcriptome data were acquired from the digestive tract and front/rear ends of D. ferox. Examining secretory proteins in D. ferox saliva helped to identify intimate connections between these proteins and membrane proteins in nasal epithelial cells. These interacting proteins played important roles in extracellular matrix (ECM)-receptor interaction, tight junction, focal adhesion, and adherens junction. The interaction between D. ferox and mammalian nasal epithelial cells included three major steps of pattern recognition, mucin connection and breakdown, and repair of ECM. The remodeling of ECM between epithelial cells of the nasal mucosa and epithelial cells of D. ferox may produce a stable adhesion environment for parasitism.

CONCLUSIONS

Our study represents the first-ever attempt to propose a molecular model for specific parasitism. This molecular model may serve as a practical reference for parasitism models of other species and a theoretical foundation for a molecular process of parasitism.

Rap1 regulates lumen continuity via Afadin in renal epithelia

The continuity of a lumen within an epithelial tubule is critical for its function. We previously found that the F-actin binding protein Afadin is required for timely lumen formation and continuity in renal tubules formed from the nephrogenic mesenchyme in mice. Afadin is a known effector and interactor of the small GTPase Rap1, and in the current study, we examine the role of Rap1 in nephron tubulogenesis. Here, we demonstrate that Rap1 is required for nascent lumen formation and continuity in cultured 3D epithelial spheroids and in vivo in murine renal epithelial tubules derived from the nephrogenic mesenchyme, where its absence ultimately leads to severe morphogenetic defects in the tubules. By contrast, Rap1 is not required for lumen continuity or morphogenesis in renal tubules derived from the ureteric epithelium, which differ in that they form by extension from a pre-existing tubule. We further demonstrate that Rap1 is required for correct localization of Afadin to adherens junctions both in vitro and in vivo. Together, these results suggest a model in which Rap1 localizes Afadin to junctional complexes, which in turn regulates nascent lumen formation and positioning to ensure continuous tubulogenesis.

Wound repair: Two distinct Rap1 pathways close the gap

Groups of cells often coordinate their movements during normal development, cancer invasion, and wound repair. These coordinated migrations require dynamic cytoskeleton and cell-junction remodeling. Two distinct Rap1 pathways are required to regulate this dynamic remodeling for rapid wound closure.

KRIT1: A Traffic Warden at the Busy Crossroads Between Redox Signaling and the Pathogenesis of Cerebral Cavernous Malformation Disease

Significance: KRIT1 (Krev interaction trapped 1) is a scaffolding protein that plays a critical role in vascular morphogenesis and homeostasis. Its loss-of-function has been unequivocally associated with the pathogenesis of Cerebral Cavernous Malformation (CCM), a major cerebrovascular disease of genetic origin characterized by defective endothelial cell-cell adhesion and ensuing structural alterations and hyperpermeability in brain capillaries. KRIT1 contributes to the maintenance of endothelial barrier function by stabilizing the integrity of adherens junctions and inhibiting the formation of actin stress fibers. Recent Advances: Among the multiple regulatory mechanisms proposed so far, significant evidence accumulated over the past decade has clearly shown that the role of KRIT1 in the stability of endothelial barriers, including the blood-brain barrier, is largely based on its involvement in the complex machinery governing cellular redox homeostasis and responses to oxidative stress and inflammation. KRIT1 loss-of-function has, indeed, been demonstrated to cause an impairment of major redox-sensitive mechanisms involved in spatiotemporal regulation of cell adhesion and signaling, which ultimately leads to decreased cell-cell junction stability and enhanced sensitivity to oxidative stress and inflammation. Critical Issues: This review explores the redox mechanisms that influence endothelial cell adhesion and barrier function, focusing on the role of KRIT1 in such mechanisms. We propose that this supports a novel model wherein redox signaling forms the common link between the various pathogenetic mechanisms and therapeutic approaches hitherto associated with CCM disease. Future Directions: A comprehensive characterization of the role of KRIT1 in redox control of endothelial barrier physiology and defense against oxy-inflammatory insults will provide valuable insights into the development of precision medicine strategies. Antioxid. Redox Signal. 38, 496-528.

Syndapin Regulates the RAP-1 GTPase to Control Endocytic Recycling via RHO-1 and Non-Muscle Myosin II

After endocytosis, many plasma membrane components are recycled via narrow-diameter membrane tubules that emerge from early endosomes to form recycling endosomes, eventually leading to their return to the plasma membrane. We previously showed that the F-BAR and SH3 domain Syndapin/PACSIN-family protein SDPN-1 is required in vivo for basolateral endocytic recycling in the C. elegans intestine. Here we sought to determine the significance of a predicted interaction between the SDPN-1 SH3 domain and a target sequence in PXF-1/PDZ-GEF1/RAPGEF2, a known exchange factor for Rap-GTPases. We found that endogenous mutations we engineered into the SDPN-1 SH3 domain, or its binding site in the PXF-1 protein, interfere with recycling in vivo , as does loss of the PXF-1 target RAP-1. Rap-GTPases have been shown in several contexts to negatively regulate RhoA activity. Our results show that RHO-1/RhoA is enriched on SDPN-1 and RAP-1 positive endosomes in the C. elegans intestine, and loss of SDPN-1 or RAP-1 elevates RHO-1(GTP) levels on intestinal endosomes. Furthermore, we found that depletion of RHO-1 suppressed sdpn-1 mutant recycling defects, indicating that control of RHO-1 activity is a key mechanism by which SDPN-1 acts to promote endocytic recycling. RHO-1/RhoA is well-known for controlling actomyosin contraction cycles, although little is known of non-muscle myosin II on endosomes. Our analysis found that non-muscle myosin II is enriched on SDPN-1 positive endosomes, with two non-muscle myosin II heavy chain isoforms acting in apparent opposition. Depletion of nmy-2 inhibited recycling like sdpn-1 mutants, while depletion of nmy-1 suppressed sdpn-1 mutant recycling defects, indicating actomyosin contractility in controlling recycling endosome function.

Small GTP-binding protein Rap1 mediates EGF and HB-EGF signaling and modulates EGF receptor expression in HTR-8/SVneo extravillous trophoblast cells

Purpose

Extravillous trophoblasts (EVTs) invade the endometrium to establish a fetomaternal interaction during pregnancy. Epidermal growth factor (EGF) and heparin-binding EGF-like growth factor (HB-EGF) stimulate EVT invasion by binding to the EGF receptor (EGFR). We examined the role of the small GTP-binding protein Rap1 in EGF- and HB-EGF-stimulated EVT invasion.

Methods

Expression of Rap1 in the first-trimester placenta was examined by immunohistochemistry. Effect of EGF or HB-EGF on Rap1 activation (GTP-Rap1) and Rap1 knockdown on invasion was assessed in EVT cell line (HTR-8/SVneo). In addition, effect of Rap1 knockdown and Rap1GAP (a Rap1 inactivator) overexpression on the activation of EGF signaling and EGFR expression were examined.

Results

Rap1 was expressed by EVTs, villous cytotrophoblasts, and syncytiotrophoblasts in the placenta. EGF and HB-EGF activated Rap1 and promoted invasion of HTR-8/SVneo, and these effects were inhibited by Rap1 knockdown. The EGF- and HB-EGF-induced phosphorylation of AKT, ERK1/2, p38MAPK, and Src was inhibited by Rap1 knockdown. Furthermore, the knockdown of Rap1 reduced the EGFR protein level. Overexpression of Rap1GAP repressed EGF- and HB-EGF-induced Rap1 activation and reduced EGFR expression.

Conclusion

Rap1 may function as a mediator of EGF and HB-EGF signaling pathways and can modulate EGFR expression in EVTs during placental development.

Deciphering the role of predicted miRNAs of polyomaviruses in carcinogenesis

Human polyomaviruses are relatively common in the general population. Polyomaviruses maintain a persistent infection after initial infection in childhood, acting as an opportunistic pathogen in immunocompromised populations and their association has been linked to carcinogenesis. A comprehensive understanding of the underlying molecular mechanisms of carcinogenesis in consequence of polyomavirus infection remains elusive. However, the critical role of viral miRNAs and their potential targets in modifying the transcriptome profile of the host remains largely unknown. Polyomavirus-derived miRNAs have the potential to play a substantial role in carcinogenesis. Employing computational approaches, putative viral miRNAs along with their target genes have been predicted and possible roles of the targeted genes in many significant biological processes have been obtained. Polyomaviruses have been observed to target intracellular signal transduction pathways through miRNA-mediated epigenetic regulation, which may contribute to cancer development. In addition, BKPyV-infected human renal cell microarray data was coupled with predicted target genes and analysis of the downregulated genes indicated that viruses target multiple signaling pathways (e.g. MAPK signaling pathway, PI3K-Akt signaling pathway, PPAR signaling pathway) in the host as well as turning off several tumor suppression genes (e.g. FGGY, EPHX2, CACNA2D3, CDH16) through miRNA-induced mechanisms, assuring cell transformation. This study provides a conceptual framework for the underlying molecular mechanisms involved in the course of carcinogenesis upon polyomavirus infection.

Mechanisms of pulmonary endothelial permeability and inflammation caused by extracellular histone subunits H3 and H4

Extracellular DNA-binding proteins such as histones are danger-associated molecular pattern released by the injured tissues in trauma and sepsis settings, which trigger host immune response and vascular dysfunction. Molecular events leading to histone-induced endothelial cell (EC) dysfunction remain poorly understood. This study performed comparative analysis of H1, H2A, H2B, H3, and H4 histone subunits effects on human pulmonary EC permeability and inflammatory response. Analysis of transendothelial electrical resistance and EC monolayer permeability for macromolecues revealed that H3 and H4, but not H1, H2A, or H2B caused dose-dependent EC permeability accompanied by disassembly of adherens junctions. At higher doses, H3 and H4 activated nuclear factor kappa B inflammatory cascade leading to upregulation EC adhesion molecules ICAM1, VCAM1, E-selectin, and release of inflammatory cytokines. Inhibitory receptor analysis showed that toll-like receptor (TLR) 4 but not TLR1/2 or receptor for advanced glycation end inhibition significantly attenuated deleterious effects of H3 and H4 histones. Inhibitor of Rho-kinase was without effect, while inhibition of Src kinase caused partial preservation of cell-cell junctions, H3/H4-induced permeability and inflammation. Deleterious effects of H3/H4 were blocked by heparin. Activation of Epac-Rap1 signaling restored EC barrier properties after histone challenge. Intravenous injection of histones in mice caused elevation of inflammatory markers and increased vascular leak. Post-treatment with pharmacological Epac/Rap1 activator suppressed injurious effects of histones in vitro and in vivo. These results identify H3 and H4 as key histone subunits exhibiting deleterious effects on pulmonary vascular endothelium via TLR4-dependent mechanism. In conclusion, elevation of circulating histones may represent a serious risk of exacerbated acute lung injury (ALI) and multiple organ injury during severe trauma and infection.

Rap1 controls epiblast morphogenesis in sync with the pluripotency states transition

The complex architecture of the murine fetus originates from a simple ball of pluripotent epiblast cells, which initiate morphogenesis upon implantation. In turn, this establishes an intermediate state of tissue-scale organization of the embryonic lineage in the form of an epithelial monolayer, where patterning signals delineate the body plan. However, how this major morphogenetic process is orchestrated on a cellular level and synchronized with the developmental progression of the epiblast is still obscure. Here, we identified that the small GTPase Rap1 plays a critical role in reshaping the pluripotent lineage. We found that Rap1 activity is controlled via Oct4/Esrrb input and is required for the transmission of polarization cues, which enables the de novo epithelialization and formation of tricellular junctions in the epiblast. Thus, Rap1 acts as a molecular switch that coordinates the morphogenetic program in the embryonic lineage, in sync with the cellular states of pluripotency.

Bacterial Nucleotidyl Cyclases Activated by Calmodulin or Actin in Host Cells: Enzyme Specificities and Cytotoxicity Mechanisms Identified to Date

Many pathogens manipulate host cell cAMP signaling pathways to promote their survival and proliferation. Bacterial Exoenzyme Y (ExoY) toxins belong to a family of invasive, structurally-related bacterial nucleotidyl cyclases (NC). Inactive in bacteria, they use proteins that are uniquely and abundantly present in eukaryotic cells to become potent, unregulated NC enzymes in host cells. Other well-known members of the family include Bacillus anthracis Edema Factor (EF) and Bordetella pertussis CyaA. Once bound to their eukaryotic protein cofactor, they can catalyze supra-physiological levels of various cyclic nucleotide monophosphates in infected cells. Originally identified in Pseudomonas aeruginosa, ExoY-related NC toxins appear now to be more widely distributed among various γ- and β-proteobacteria. ExoY-like toxins represent atypical, poorly characterized members within the NC toxin family. While the NC catalytic domains of EF and CyaA toxins use both calmodulin as cofactor, their counterparts in ExoY-like members from pathogens of the genus Pseudomonas or Vibrio use actin as a potent cofactor, in either its monomeric or polymerized form. This is an original subversion of actin for cytoskeleton-targeting toxins. Here, we review recent advances on the different members of the NC toxin family to highlight their common and distinct functional characteristics at the molecular, cytotoxic and enzymatic levels, and important aspects that need further characterizations.

The substrate stiffness at physiological range significantly modulates vascular cell behavior

Changes in the stiffness of the cellular microenvironment are involved in many pathological processes of blood vessels. Substrate stiffness has been shown to have extensive effects on vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs). However, the material stiffness of most previously reported in-vitro models is ranging from ~100 kPa to the magnitude of MPa, which does not match the mechanical properties of natural vascular tissue (10-100 kPa). Herein, we constructed hydrogel substrates with the stiffness of 18-86 kPa to explore the effect of physiological stiffness on vascular cells. Our findings show that, with the increase of stiffness at the physiological range, the cell adhesion and proliferation behaviors of VECs and VSMCs are significantly enhanced. On the soft substrate, VECs express more nitric oxide (NO), and VSMCs tend to maintain a healthy contraction phenotype. More importantly, we find that the number of differentially expressed genes in cells cultured between 18 kPa and 86 kPa substrates (560 in VECs, 243 in VSMCs) is significantly higher than that between 86 kPa and 333 kPa (137 in VECs, 172 in VSMCs), indicating that a small increase in stiffness within the physiological range have a higher impact on vascular cell behaviors. Overall, our results expanded the exploration of how stiffness affects the behavior of vascular cells at the physiological range.

Identification of differentially expressed genes at different post-natal development stages of longissimus dorsi muscle in Tianzhu white yak

The regulatory mechanisms controlling post-natal muscle development in the yak (Bos grunniens) are still largely unknown, yet the growth and development of muscle is a complex process that plays a crucial role in determining the yield and quality of an animal's meat. In this study, we performed a transcriptome analysis based on the RNA sequencing (RNA-Seq) of yak longissimus dorsi muscle tissue obtained from calves (6 months of age; 6 M), young adults (30 months of age; 30 M) and adult (54 months of age; 54 M) to identify which genes are differentially expressed and to investigate their temporal expression profiles. In total, 1788 differentially expressed genes (DEGs) (|log2FC| ≥ 1, P-adjusted < 0.05) were detected by pairwise comparisons between the different age groups. The expression levels of 10 of the DEGs were confirmed using reverse transcription-quantitative PCR (RT-qPCR), and the results were consistent with the transcriptome profile. A time-series expression profile analysis clustered the DEGs into four groups that could be divided into two classes (P < 0.05): class 1 profiles, which had up-regulated patterns of gene expression and class 2 profiles, which featured down-regulated patterns. Based on that cluster analysis, GO enrichment analysis revealed 1073, 127, and 184 terms as significantly enriched in biological process (BP), cellular component (CC), and molecular function (MF) categories in the class 1 profiles, while 714, 66, and 206 terms were significantly enriched in BP, CC, and MF in the class 2 profiles. A KEGG pathway analysis revealed that DEGs from the class 1 profiles were enriched in 62 pathways, with the most enriched being the phosphoinositide 3-kinase (PI3K) - protein kinase B (Akt)-signaling pathway. The DEGs from the class 2 profiles were enriched in 16 pathways, of which forkhead box protein O (FoxO) - signaling was the most enriched. Taken together, these results provide insight into the mechanisms of skeletal muscle development, as well suggesting some potential genes of importance for yak meat production.

Radiobiological effects of wound fluid on breast cancer cell lines and human-derived tumor spheroids in 2D and microfluidic culture

Intraoperative radiotherapy (IORT) could abrogate cancer recurrences, but the underlying mechanisms are unclear. To clarify the effects of IORT-induced wound fluid on tumor progression, we treated breast cancer cell lines and human-derived tumor spheroids in 2D and microfluidic cell culture systems, respectively. The viability, migration, and invasion of the cells under treatment of IORT-induced wound fluid (WF-RT) and the cells under surgery-induced wound fluid (WF) were compared. Our findings showed that cell viability was increased in spheroids under both WF treatments, whereas viability of the cell lines depended on the type of cells and incubation times. Both WFs significantly increased sub-G1 and arrested the cells in G0/G1 phases associated with increased P16 and P21 expression levels. The expression level of Caspase 3 in both cell culture systems and for both WF-treated groups was significantly increased. Furthermore, our results revealed that although the migration was increased in both systems of WF-treated cells compared to cell culture media-treated cells, E-cadherin expression was significantly increased only in the WF-RT group. In conclusion, WF-RT could not effectively inhibit tumor progression in an ex vivo tumor-on-chip model. Moreover, our data suggest that a microfluidic system could be a suitable 3D system to mimic in vivo tumor conditions than 2D cell culture.

Talin‑1 interaction network in cellular mechanotransduction (Review)

The mechanical signals within the extracellular matrix (ECM) regulate cell growth, proliferation and differentiation, and integrins function as the hub between the ECM and cellular actin. Focal adhesions (FAs) are multi‑protein, integrin‑containing complexes, acting as tension‑sensing anchoring points that bond cells to the extracellular microenvironment. Talin‑1 serves as the central protein of FAs that participates in the activation of integrins and connects them with the actin cytoskeleton. As a cytoplasmic protein, Talin‑1 consists of a globular head domain and a long rod comprised of a series of α‑helical bundles. The unique structure of the Talin‑1 rod domain permits folding and unfolding in response to the mechanical stress, revealing various binding sites. Thus, conformation changes of the Talin‑1 rod domain enable the cell to convert mechanical signals into chemical through multiple signaling pathways. The present review discusses the binding partners of Talin‑1, their interactions, effects on the cellular processes, and their possible roles in diseases.

Knockdown of CDR1as Decreases Differentiation of Goat Skeletal Muscle Satellite Cells via Upregulating miR-27a-3p to Inhibit ANGPT1

Myogenesis is a complex process controlled by several coding and non-coding RNAs (ncRNAs), such as circular RNAs (circRNAs) that are known to function as endogenous microRNAs (miRNAs) sponges. Cerebellar Degeneration-Related protein 1 antisense (CDR1as) is the most spotlighted circRNA that is known as an miR-7 sponge, which has bloomed circRNAs’ research in animal disease and physiology. Here, we screened for miRNAs and mRNA associated with CDR1as and further characterized their regulatory function during muscle differentiation. We found that a total of 43 miRNAs (including miR-107-3p, miR-125b-5p, miR-140-5p, miR-29a-3p, and miR-27a-3p upregulated) and 789 mRNAs (including ANGPT1, E2F2, CCN1, FGFR1, and MEF2C downregulated) were differentially expressed in goat skeletal muscle satellite cells (SMSCs). Further, knockdown of CDR1as and ANGPT1 inhibited SMSCs differentiation. miR-27a-3p was differentially upregulated after the knockdown of CDR1as in SMSCs. Overexpressed miR-27a-3p decreased SMSCs differentiation. Via RNAhybrid and luciferase, miR-27a-3p was identified to regulate ANGPT1. We discovered that miR-27a-3p has an inverse relationship with CDR1as and decreases the expression level of ANGPT1 during SMSCs differentiation. In summary, our study demonstrates that siCDR1as inhibits myoblast differentiation by downregulating ANGPT1 mRNA via miR-27a-3p in SMSCs.

Ubiquitylation by Rab40b/Cul5 regulates Rap2 localization and activity during cell migration

Cell migration is a complex process that involves coordinated changes in membrane transport and actin cytoskeleton dynamics. Ras-like small monomeric GTPases, such as Rap2, play a key role in regulating actin cytoskeleton dynamics and cell adhesions. However, how Rap2 function, localization, and activation are regulated during cell migration is not fully understood. We previously identified the small GTPase Rab40b as a regulator of breast cancer cell migration. Rab40b contains a suppressor of cytokine signaling (SOCS) box, which facilitates binding to Cullin5, a known E3 ubiquitin ligase component responsible for protein ubiquitylation. In this study, we show that the Rab40b/Cullin5 complex ubiquitylates Rap2. Importantly, we demonstrate that ubiquitylation regulates Rap2 activation as well as recycling of Rap2 from the endolysosomal compartment to the lamellipodia of migrating breast cancer cells. Based on these data, we propose that Rab40b/Cullin5 ubiquitylates and regulates Rap2-dependent actin dynamics at the leading edge, a process that is required for breast cancer cell migration and invasion.

Emerging Roles of Non-Coding RNAs in the Feed Efficiency of Livestock Species

A global population of already more than seven billion people has led to an increased demand for food and water, and especially the demand for meat. Moreover, the cost of feed used in animal production has also increased dramatically, which requires animal breeders to find alternatives to reduce feed consumption. Understanding the biology underlying feed efficiency (FE) allows for a better selection of feed-efficient animals. Non-coding RNAs (ncRNAs), especially micro RNAs (miRNAs) and long non-coding RNAs (lncRNAs), play important roles in the regulation of bio-logical processes and disease development. The functions of ncRNAs in the biology of FE have emerged as they participate in the regulation of many genes and pathways related to the major FE indicators, such as residual feed intake and feed conversion ratio. This review provides the state of the art studies related to the ncRNAs associated with FE in livestock species. The contribution of ncRNAs to FE in the liver, muscle, and adipose tissues were summarized. The research gap of the function of ncRNAs in key processes for improved FE, such as the nutrition, heat stress, and gut–brain axis, was examined. Finally, the potential uses of ncRNAs for the improvement of FE were discussed.

COVID-19 Infection During Pregnancy Induces Differential Gene Expression in Human Cord Blood Cells From Term Neonates

BACKGROUND

The COVID-19 pandemic continues worldwide with fluctuating case numbers in the United States. This pandemic has affected every segment of the population with more recent hospitalizations in the pediatric population. Vertical transmission of COVID-19 is uncommon, but reports show that there are thrombotic, vascular, and inflammatory changes in the placenta to which neonates are prenatally exposed. Individuals exposed in utero to influenza during the 1918 pandemic had increased risk for heart disease, kidney disease, diabetes, stomach disease and hypertension. Early exposure of COVID-19 during fetal life may lead to altered gene expression with potential long-term consequences.

OBJECTIVE

To determine if gene expression is altered in cord blood cells from term neonates who were exposed to COVID-19 during pregnancy and to identify potential gene pathways impacted by maternal COVID-19.

METHODS

Cord blood was collected from 16 term neonates (8 exposed to COVID-19 during pregnancy and 8 controls without exposure to COVID-19). Genome-wide gene expression screening was performed using Human Clariom S gene chips on total RNA extracted from cord blood cells.

RESULTS

We identified 510 differentially expressed genes (374 genes up-regulated, 136 genes down-regulated, fold change ≥1.5, p-value ≤ 0.05) in cord blood cells associated with exposure to COVID-19 during pregnancy. Ingenuity Pathway Analysis identified important canonical pathways associated with diseases such as cardiovascular disease, hematological disease, embryonic cancer and cellular development. Tox functions related to cardiotoxicity, hepatotoxicity and nephrotoxicity were also altered after exposure to COVID-19 during pregnancy.

CONCLUSIONS

Exposure to COVID-19 during pregnancy induces differential gene expression in cord blood cells. The differentially expressed genes may potentially contribute to cardiac, hepatic, renal and immunological disorders in offspring exposed to COVID-19 during pregnancy. These findings lead to a further understanding of the effects of COVID-19 exposure at an early stage of life and its potential long-term consequences as well as therapeutic targets.

Multivalent interactions make adherens junction-cytoskeletal linkage robust during morphogenesis

Embryogenesis requires cells to change shape and move without disrupting epithelial integrity. This requires robust, responsive linkage between adherens junctions and the actomyosin cytoskeleton. Using Drosophila morphogenesis, we define molecular mechanisms mediating junction-cytoskeletal linkage and explore the role of mechanosensing. We focus on the junction-cytoskeletal linker Canoe, a multidomain protein. We engineered the canoe locus to define how its domains mediate its mechanism of action. To our surprise, the PDZ and FAB domains, which we thought connected junctions and F-actin, are not required for viability or mechanosensitive recruitment to junctions under tension. The FAB domain stabilizes junctions experiencing elevated force, but in its absence, most cells recover, suggesting redundant interactions. In contrast, the Rap1-binding RA domains are critical for all Cno functions and enrichment at junctions under tension. This supports a model in which junctional robustness derives from a large protein network assembled via multivalent interactions, with proteins at network nodes and some node connections more critical than others.

Plexin-B2 orchestrates collective stem cell dynamics via actomyosin contractility, cytoskeletal tension and adhesion

During morphogenesis, molecular mechanisms that orchestrate biomechanical dynamics across cells remain unclear. Here, we show a role of guidance receptor Plexin-B2 in organizing actomyosin network and adhesion complexes during multicellular development of human embryonic stem cells and neuroprogenitor cells. Plexin-B2 manipulations affect actomyosin contractility, leading to changes in cell stiffness and cytoskeletal tension, as well as cell-cell and cell-matrix adhesion. We have delineated the functional domains of Plexin-B2, RAP1/2 effectors, and the signaling association with ERK1/2, calcium activation, and YAP mechanosensor, thus providing a mechanistic link between Plexin-B2-mediated cytoskeletal tension and stem cell physiology. Plexin-B2-deficient stem cells exhibit premature lineage commitment, and a balanced level of Plexin-B2 activity is critical for maintaining cytoarchitectural integrity of the developing neuroepithelium, as modeled in cerebral organoids. Our studies thus establish a significant function of Plexin-B2 in orchestrating cytoskeletal tension and cell-cell/cell-matrix adhesion, therefore solidifying the importance of collective cell mechanics in governing stem cell physiology and tissue morphogenesis.

EPAC2 acts as a negative regulator in Matrigel-driven tubulogenesis of human microvascular endothelial cells

Angiogenesis is physiologically essential for embryogenesis and development and reinitiated in adult animals during tissue growth and repair. Forming new vessels from the walls of existing vessels occurs as a multistep process coordinated by sprouting, branching, and a new lumenized network formation. However, little is known regarding the molecular mechanisms that form new tubular structures, especially molecules regulating the proper network density of newly formed capillaries. This study conducted microarray analyses in human primary microvascular endothelial cells (HMVECs) plated on Matrigel. The RAPGEF4 gene that encodes exchange proteins directly activated by cAMP 2 (EPAC2) proteins was increased in Matrigel-driven tubulogenesis. Tube formation was suppressed by the overexpression of EPAC2 and enhanced by EPAC2 knockdown in endothelial cells. Endothelial cell morphology was changed to round cell morphology by EPAC2 overexpression, while EPAC2 knockdown showed an elongated cell shape with filopodia-like protrusions. Furthermore, increased EPAC2 inhibited endothelial cell migration, and ablation of EPAC2 inversely enhanced cell mobility. These results suggest that EPAC2 affects the morphology and migration of microvascular endothelial cells and is involved in the termination and proper network formation of vascular tubes.

Synthesis, Antitumor Activity, Molecular Docking and DFT Study of Novel Pyrimidiopyrazole Derivatives

BACKGROUND

In this investigation, 2-cyano-N-(2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl) acetamide (3) reacts with dimethylformamide dimethyl acetal (DMF-DMA) to afford the corresponding (E)- 2-cyano-3-(dimethylamino)-N-(2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)acrylam-ide (4) utilizing microwave irradiation. The condensation reactions of acrylamide derivative 4 with hydrazine derivatives obtain pyrazole derivatives 6a and 6b; respectively. The synthesized compounds demonstrate in vitro antitumor activity against liver tumor cell line HepG2. Furthermore, additional studies were carried out on the most effective compound 6b to evaluate the potential interaction against 4hdq synthase complex with ΔE= -4.5Kcal/mol and with short distance = 1.727Å and 2.027Å, respectively. The comprehensive theoretical studies of compounds 6a and 6b is based on bond length, bond angles and energy gap HOMO-LUMO. In addition, the vibrational frequencies of optimized compounds 6a and 6b were examined through DFT/B3LYP/6+31G(d) basis set.

METHODS

In this research, synthesis of novel pyrimidiopyrazole derivatives calculated the computational studies to find suitable drug-receptor interactions and biological activity.

RESULTS AND DISCUSSION

The synthesized pyrimidiopyrazole derivative 6b exhibited high antitumor activity IC50 =12.6 μg/ml and interacted it with 4hdq synthase complex with ΔE=-4.5Kcal/mol and with short distance = 1.727Å and 2.027Å. Furthermore, the optimized compounds utilize Gaussian 09W.

CONCLUSION

In the optimized pyrimidiopyrazole derivatives, 6b showed better antitumor activity HeG-2 against 5-flurouracil due to its energy and confirmed more potent of hydrogen bond interaction with protein pocket.

Effects of Ruscus extract on muscarinic receptors: Is there a role for endothelium derived relaxing factors on macromolecular permeability protection and microvascular diameter changes?

BACKGROUND

Protective effects of Ruscus extract on macromolecular permeability depend on its capacity to stimulate muscarinic receptors on endothelial cells and induce the release of endothelium derived relaxing factors (EDRFs).

OBJECTIVE

To investigate if these effects depend only on activation of muscarinic receptors or if EDRFs release are also necessary. We have also investigated the participation of Ruscus extract on muscarinic-induced release of EDRFs on microvascular diameters.

METHODS

Hamsters were treated daily during two weeks with Ruscus extract (50, 150 and 450 mg/kg/day) and then macromolecular permeability induced by histamine and arteriolar and venular diameters after cyclooxygenase (COX) and nitric oxide synthase (NOS) inhibitors: indomethacin and Nω-Nitro-L-arginine (LNA), respectively applied topically at 10-8M, 10-6M and 10-4M were observed on the cheek pouch preparation.

RESULTS

Ruscus extract decreased macromolecular permeability in a dose-dependent fashion and did not affect microvascular diameters. NOS and COX inhibitors enhanced its effect on microvascular permeability. NOS inhibition reduced arteriolar diameter and COX blocking decreased arteriolar and venular diameters at the lowest dose and increased them at higher doses of Ruscus extract.

CONCLUSION

The protective effect of Ruscus extract on macromolecular permeability seems to be mediated only via muscarinic receptors. Muscarinic activation attenuated vasoconstrictive tone through cyclooxygenase-independent endothelium derived relaxing factors.

Cannibalized erythroblasts accelerate developmental neurogenesis by regulating mitochondrial dynamics

Metabolic support was long considered to be the only developmental function of hematopoiesis, a view that is gradually changing. Here, we disclose a mechanism triggered during neurulation that programs brain development by donation of sacrificial yolk sac erythroblasts to neuroepithelial cells. At embryonic day (E) 8.5, neuroepithelial cells transiently integrate with the endothelium of yolk sac blood vessels and cannibalize intravascular erythroblasts as transient heme-rich endosymbionts. This cannibalistic behavior instructs precocious neuronal differentiation of neuroepithelial cells in the proximity of blood vessels. By experiments in vitro, we show that access to erythroblastic heme accelerates the pace of neurogenesis by induction of a truncated neurogenic differentiation program from a poised state. Mechanistically, the poised state is invoked by activation of the mitochondrial electron transport chain that leads to amplified production of reactive oxygen species in addition to omnipresent guanosine triphosphate (GTP) with consequential upregulation of pro-differentiation β-catenin.

Cortical expression of the RAPGEF1 gene in schizophrenia: investigating regional differences and suicide

Rap guanine nucleotide exchange factor 1 (RAPGEF1) is involved in cell adhesion and neuronal migration. Previously we found lower RAPGEF1 mRNA levels in Brodmann's area (BA) 9 in subjects with schizophrenia compared to controls. This study aimed to determine whether RAPGEF1 expression was altered in other brain regions implicated in schizophrenia and whether this was associated with suicide. Using qPCR, we measured the levels of RAPGEF1 in post-mortem BA 8 and 44 from 27 subjects with schizophrenia and 26 non-psychiatric control subjects. To address the effect of antipsychotic treatments, Rapgef1 mRNA levels were measured in the cortex from rats treated with typical antipsychotic drugs. There was no difference in RAPGEF1 normalised relative expression levels in BA 8 or 44. However, in BA 8, schizophrenia subjects had higher raw Ct RAPGEF1 levels compared to controls. There were higher RAPGEF1 levels in suicide completers compared to non-suicide schizophrenia subjects in BA 8. Rapgef1 expression levels in the rat cortex did not vary with antipsychotic treatment. Our findings suggest changes in RAPGEF1 expression may be limited to the dorsolateral prefrontal cortex from subjects with schizophrenia. Further investigation of the function of RAPGEF1 may lead to a greater understanding of the pathophysiology of schizophrenia.

Rap2B promotes the proliferation and migration of human glioma cells via activation of the ERK pathway

Glioma is one of the most common primary brain tumors and has a poor prognosis. Rap2B, a member of the Ras family of oncogenes, is highly expressed and promotes the progression of several tumors, including glioma. However, the mechanism underlying the role of Rap2B in glioma is not fully understood. In the present study, after transfection, Rap2B expression was detected by reverse transcription PCR and western blot analysis. Cell proliferation and cell migration assays were performed to determine the effects of Rap2B on the malignant biological behaviors of glioma cells. The changes of ERK pathway-associated proteins were examined by western blot analysis. Enzyme-linked immunosorbent assay (ELISA) and western blot analysis were utilized to detect the protein levels of matrix metalloproteinase (MMP)2 and MMP9. Then, The Cancer Genome Atlas database was used to determine the association between Rap2B expression and clinical parameters in patients with glioblastoma multiforme and low-grade glioma (LGG). Results revealed that Rap2B was highly expressed in human glioma compared with that in adjacent normal tissues and normal human astrocytes, and that silenced Rap2B led to a reduction of cell proliferation and migration ability in glioma cells. Conversely, overexpressed Rap2B in both U87 and U251 cells significantly enhanced these malignant activities. In addition, ELISA assay and western blotting showed that Rap2B increased MMP2 and MMP9 expression. The western blot assay revealed that Rap2B induced the phosphorylation of ERK in glioma cells. Furthermore, silencing the ERK pathway by SCH772984 led to the inhibition of Rap2B-mediated proliferation, migration and the reduction of MMP2 and MMP9 expression. Kaplan-Meier analysis revealed that increased Rap2B expression was associated with poorer survival of patients with LGG. These results demonstrated that Rap2B may participate in the processes of glioma cell proliferation and migration through enhancing MMP2 and MMP9 expression via the ERK pathway. Thus, Rap2B could potentially be used as a promising therapeutic target and prognostic biomarker in glioma.

Plexin-B2 facilitates glioblastoma infiltration by modulating cell biomechanics

Infiltrative growth is a major cause of high lethality of malignant brain tumors such as glioblastoma (GBM). We show here that GBM cells upregulate guidance receptor Plexin-B2 to gain invasiveness. Deletion of Plexin-B2 in GBM stem cells limited tumor spread and shifted invasion paths from axon fiber tracts to perivascular routes. On a cellular level, Plexin-B2 adjusts cell adhesiveness, migratory responses to different matrix stiffness, and actomyosin dynamics, thus empowering GBM cells to leave stiff tumor bulk and infiltrate softer brain parenchyma. Correspondingly, gene signatures affected by Plexin-B2 were associated with locomotor regulation, matrix interactions, and cellular biomechanics. On a molecular level, the intracellular Ras-GAP domain contributed to Plexin-B2 function, while the signaling relationship with downstream effectors Rap1/2 appeared variable between GBM stem cell lines, reflecting intertumoral heterogeneity. Our studies establish Plexin-B2 as a modulator of cell biomechanics that is usurped by GBM cells to gain invasiveness.

Using mRNA deep sequencing to analyze differentially expressed genes during Panax notoginseng saponin treatment of ischemic stroke

Treatment with Panax notoginseng saponin (PNS) can prevent neurological damage in middle cerebral artery occlusion model rats to promote recovery after a stroke. However, the exact molecular mechanisms are unknown and require further study. In the present study, mRNA sequencing was employed to investigate differential gene expression between model and sham groups, and between model and PNS‑treated groups. Enrichment of gene data was performed using Gene Ontology analysis and the Kyoto Encyclopedia of Genes and Genomes database. Hub genes were identified and networks were constructed using Cytoscape that were further verified by reverse transcription‑quantitative PCR. A total of 1,104 genes of interest were found, which included 690 upregulated and 414 downregulated genes that were identified when the model was compared with the sham group. Additionally, 817 genes of interest, which included 390 upregulated and 427 downregulated genes, were identified when the PNS‑treated group was compared with the model group. There were 303 overlapping genes of interest between the analysis of model to sham groups, and the analysis of model to PNS‑treated groups. The top 10 genes from the 303 aberrantly expressed genes of interest included ubiquitin conjugating enzyme E2 variant 2, small ubiquitin‑related modifier 1, small RNA binding exonuclease protection factor La, Finkel‑Biskis‑Reilly murine sarcoma virus (FBR‑MuSV) ubiquitously expressed, centrosomal protein 290 kDa, DNA‑directed RNA polymerase II subunit K, cullin‑4B, matrin‑3 and vascular endothelial growth factor receptor 2. In conclusion, these genes may be important in the underlying mechanism of PNS treatment in ischemic stroke. Additionally, the present data provided novel insight into the pathogenesis of ischemic stroke.

Potential Diagnostic and Prognostic Utility of miR-141, miR-181b1, and miR-23b in Breast Cancer

miRNAs, a group of short noncoding RNAs, are key regulators of fundamental cellular processes and signaling pathways. Dysregulation of miRNA expression with known oncogenic or tumor suppressor functions has been associated with neoplastic transformation. Numerous studies have reported dysregulation of miRNA-141, miR-181b1, and miR-23b in a wide range of malignancies, including breast cancer. To the best of our knowledge, no previous study had demonstrated the expression of miR-141-3p, miR-181b1-5p, and miR-23b-3p in different histological grades and molecular subtypes of breast cancer. Here, we identified differential expression of these three miRNAs in breast cancer tissues compared with benign breast fibroadenomas. In addition, high expression levels of miR-141-3p and miR-181b1-5p are strongly associated with aggressive breast carcinomas. We also confirmed the clinical potential of using the three miRNAs individually or combined as diagnostic and prognostic markers in breast cancer. Using bioinformatics analyses, we identified 23 hub genes of these three miRNAs which are involved in key signaling pathways in breast cancer. Furthermore, the KM plotter online database analysis demonstrates the association between elevated expression of miR-141 and miR-181b and shorter overall survival of breast cancer patients. Together, our data suggest an oncogenic role of the studied miRNAs and highlight their molecular roles and potential clinical applications in breast cancer.

p90RSK-MAGI1 Module Controls Endothelial Permeability by Post-translational Modifications of MAGI1 and Hippo Pathway

Previously, we reported that post-translational modifications (PTMs) of MAGI1, including S741 phosphorylation and K931 de-SUMOylation, both of which are regulated by p90RSK activation, lead to endothelial cell (EC) activation. However, roles for p90RSK and MAGI1-PTMs in regulating EC permeability remain unclear despite MAGI1 being a junctional molecule. Here, we show that thrombin (Thb)-induced EC permeability, detected by the electric cell-substrate impedance sensing (ECIS) based system, was decreased by overexpression of dominant negative p90RSK or a MAGI1-S741A phosphorylation mutant, but was accelerated by overexpression of p90RSK, siRNA-mediated knockdown of magi1, or the MAGI1-K931R SUMOylation mutant. MAGI1 depletion also increased the mRNA and protein expression of the large tumor suppressor kinases 1 and 2 (LATS1/2), which inhibited YAP/TAZ activity and increased EC permeability. Because the endothelial barrier is a critical mediator of tumor hypoxia, we also evaluated the role of p90RSK activation in tumor vessel leakiness by using a relatively low dose of the p90RSK specific inhibitor, FMK-MEA. FMK-MEA significantly inhibited tumor vessel leakiness at a dose that does not affect morphology and growth of tumor vessels in vivo. These results provide novel insights into crucial roles for p90RSK-mediated MAGI1 PTMs and the Hippo pathway in EC permeability, as well as p90RSK activation in tumor vessel leakiness.

Plasmatic Membrane Expression of Adhesion Molecules in Human Cardiac Progenitor/Stem Cells Might Explain Their Superior Cell Engraftment after Cell Transplantation

Human bone marrow mesenchymal stem cells (BM-MSCs) and cardiac progenitor/stem cells (CPCs) have been extensively studied as a potential therapeutic treatment for myocardial infarction (MI). Previous reports suggest that lower doses of CPCs are needed to improve cardiac function relative to their bone marrow counterparts. Here, we confirmed this observations and investigated the surface protein expression profile that might explain this effect. Myocardial infarction was performed in nude rats by permanent ligation of the left coronary artery. Cardiac function and infarct size before and after cell transplantation were evaluated by echocardiography and morphometry, respectively. The CPC and BM-MSC receptome were analyzed by proteomic analysis of biotin-labeled surface proteins. Rats transplanted with CPCs showed a greater improvement in cardiac function after MI than those transplanted with BM-MSCs, and this was associated with a smaller infarct size. Analysis of the receptome of CPCs and BM-MSCs showed that gene ontology biological processes and KEGG pathways associated with adhesion mechanisms were upregulated in CPCs compared with BM-MSCs. Moreover, the membrane protein interactome in CPCs showed a strong relationship with biological processes related to cell adhesion whereas the BM-MSCs interactome was more related to immune regulation processes. We conclude that the stronger capacity of CPCs over BM-MSCs to engraft in the infarcted area is likely linked to a more pronounced cell adhesion expression program.

C3G Is Upregulated in Hepatocarcinoma, Contributing to Tumor Growth and Progression and to HGF/MET Pathway Activation

The complexity of hepatocellular carcinoma (HCC) challenges the identification of disease-relevant signals. C3G, a guanine nucleotide exchange factor for Rap and other Ras proteins, plays a dual role in cancer acting as either a tumor suppressor or promoter depending on tumor type and stage. The potential relevance of C3G upregulation in HCC patients suggested by database analysis remains unknown. We have explored C3G function in HCC and the underlying mechanisms using public patient data and in vitro and in vivo human and mouse HCC models. We found that C3G is highly expressed in progenitor cells and neonatal hepatocytes, whilst being down-regulated in adult hepatocytes and re-expressed in human HCC patients, mouse HCC models and HCC cell lines. Moreover, high C3G mRNA levels correlate with tumor progression and a lower patient survival rate. C3G expression appears to be tightly modulated within the HCC program, influencing distinct cell biological properties. Hence, high C3G expression levels are necessary for cell tumorigenic properties, as illustrated by reduced colony formation in anchorage-dependent and -independent growth assays induced by permanent C3G silencing using shRNAs. Additionally, we demonstrate that C3G down-regulation interferes with primary HCC tumor formation in xenograft assays, increasing apoptosis and decreasing proliferation. In vitro assays also revealed that C3G down-regulation enhances the pro-migratory, invasive and metastatic properties of HCC cells through an epithelial-mesenchymal switch that favors the acquisition of a more mesenchymal phenotype. Consistently, a low C3G expression in HCC cells correlates with lung metastasis formation in mice. However, the subsequent restoration of C3G levels is associated with metastatic growth. Mechanistically, C3G down-regulation severely impairs HGF/MET signaling activation in HCC cells. Collectively, our results indicate that C3G is a key player in HCC. C3G promotes tumor growth and progression, and the modulation of its levels is essential to ensure distinct biological features of HCC cells throughout the oncogenic program. Furthermore, C3G requirement for HGF/MET signaling full activation provides mechanistic data on how it works, pointing out the relevance of assessing whether high C3G levels could identify HCC responders to MET inhibitors.

GGPS1 Mutations Cause Muscular Dystrophy/Hearing Loss/Ovarian Insufficiency Syndrome

OBJECTIVE

A hitherto undescribed phenotype of early onset muscular dystrophy associated with sensorineural hearing loss and primary ovarian insufficiency was initially identified in 2 siblings and in subsequent patients with a similar constellation of findings. The goal of this study was to understand the genetic and molecular etiology of this condition.

METHODS

We applied whole exome sequencing (WES) superimposed on shared haplotype regions to identify the initial biallelic variants in GGPS1 followed by GGPS1 Sanger sequencing or WES in 5 additional families with the same phenotype. Molecular modeling, biochemical analysis, laser membrane injury assay, and the generation of a Y259C knock-in mouse were done.

RESULTS

A total of 11 patients in 6 families carrying 5 different biallelic pathogenic variants in specific domains of GGPS1 were identified. GGPS1 encodes geranylgeranyl diphosphate synthase in the mevalonate/isoprenoid pathway, which catalyzes the synthesis of geranylgeranyl pyrophosphate, the lipid precursor of geranylgeranylated proteins including small guanosine triphosphatases. In addition to proximal weakness, all but one patient presented with congenital sensorineural hearing loss, and all postpubertal females had primary ovarian insufficiency. Muscle histology was dystrophic, with ultrastructural evidence of autophagic material and large mitochondria in the most severe cases. There was delayed membrane healing after laser injury in patient-derived myogenic cells, and a knock-in mouse of one of the mutations (Y259C) resulted in prenatal lethality.

INTERPRETATION

The identification of specific GGPS1 mutations defines the cause of a unique form of muscular dystrophy with hearing loss and ovarian insufficiency and points to a novel pathway for this clinical constellation. ANN NEUROL 2020;88:332-347.