The Ras activator RasGRP3 mediates diabetes-induced embryonic defects and affects endothelial cell migration

Incubation with porcine urinary bladder matrix yields a late-stage wound transcriptome in endothelial cells and keratinocytes isolated from both diabetic and non-diabetic subjects

Proper wound closure requires the functional coordination of endothelial cells (ECs) and keratinocytes. In the late stages of wound healing, keratinocytes become activated and ECs promote the maturation of nascent blood vessels. In diabetes mellitus, decreased keratinocyte activation and impaired angiogenic action of ECs delay wound healing. Porcine urinary bladder matrix (UBM) improves the rate of wound healing, but the effect of exposure to UBM under diabetic conditions remains unclear. We hypothesized that keratinocytes and ECs isolated from both diabetic and non-diabetic donors would exhibit a similar transcriptome representative of the later stages of wound healing following incubation with UBM. Human keratinocytes and dermal ECs isolated from non-diabetic and diabetic donors were incubated with and without UBM particulate. RNA-Seq analysis was performed to identify changes in the transcriptome of these cells associated with exposure to UBM. While diabetic and non-diabetic cells exhibited different transcriptomes, these differences were minimized following incubation with UBM. ECs exposed to UBM exhibited changes in the expression of transcripts suggesting an increase in the endothelial-mesenchymal transition (EndoMT) associated with vessel maturation. Keratinocytes incubated with UBM demonstrated an increase in markers of activation. Comparison of the whole transcriptomes with public datasets suggested increased EndoMT and keratinocyte activation following UBM exposure. Both cell types exhibited loss of pro-inflammatory cytokines and adhesion molecules. These data suggest that application of UBM may accelerate healing by promoting a transition to the later stages of wound healing. This healing phenotype is achieved in cells isolated from both diabetic and non-diabetic donors.

The Role of RASGRP2 in Vascular Endothelial Cells-A Mini Review

RAS guanyl nucleotide-releasing proteins (RASGRPs) are important proteins that act as guanine nucleotide exchange factors, which activate small GTPases and function as molecular switches for intracellular signals. The RASGRP family is composed of RASGRP1-4 proteins and activates the small GTPases, RAS and RAP. Among them, RASGRP2 has different characteristics from other RASGRPs in that it targets small GTPases and its localizations are different. Many studies related to RASGRP2 have been reported in cells of the blood cell lineage. Furthermore, RASGRP2 has also been reported to be associated with Huntington's disease, tumors, and rheumatoid arthritis. In addition, we also recently reported RASGRP2 expression in vascular endothelial cells, and clarified the involvement of xenopus Rasgrp2 in the vasculogenesis process and multiple signaling pathways of RASGRP2 in human vascular endothelial cells with stable expression of RASGRP2. Therefore, this article outlines the existing knowledge of RASGRP2 and focuses on its expression and role in vascular endothelial cells, and suggests that RASGRP2 functions as a protective factor for maintaining healthy blood vessels.

Identification of biomarkers associated with metabolic cardiovascular disease using mRNA-SNP-miRNA regulatory network analysis

Background

CVD is the leading cause of death in T2DM patients. However, few biomarkers have been identified to detect and diagnose CVD in the early stage of T2DM. The aim of our study was to identify the important mRNAs, micro (mi)RNAs and SNPs (single nucleotide polymorphisms) that are associated with metabolic cardiovascular disease.

Materials and methods

Expression profiles and GWAS data were obtained from Gene Expression Omnibus (GEO) database. MiRNA-sequencing was conducted by Illumina HiSeq 2000 platform in T2DM patients and T2DM with CVD patients. EQTL analysis and gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted. MRNA-miRNA co-expression network and mRNA-SNP-miRNA interaction network were established and visualized by Cytoscape 3.7.2.

Results

In our study, we identified 56 genes and 16 miRNAs that were significantly differentially expressed. KEGG analyses results indicated that B cell receptor signaling pathway and hematopoietic cell lineage were included in the biological functions of differentially expressed genes. MRNA-miRNA co-expression network and mRNA-SNP-miRNA interaction network illustrated that let-7i-5p, RASGRP3, KRT1 and CEP41 may be potential biomarkers for the early detection and diagnosis of CVD in T2DM patients.

Conclusion

Our results suggested that downregulated let-7i-5p, and upregulated RASGRP3, KRT1 and CEP41 may play crucial roles in molecular mechanisms underlying the initiation and development of CVD in T2DM patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02166-4.

Talin1 regulates endometrial adhesive capacity through the Ras signaling pathway

AIMS

Blastocyst implantation is mainly depended on the adhesion between cells and cell matrix. Endometrial adhesion plays an important role in establishing embryo implantation, but the underlying mechanisms are remains unclear. Talin1 is a local adhesion complex protein that is necessary for cell adhesion and movement. However, the role and mechanisms of Talin1 in embryo implantation are still unclear.

MAIN METHODS

The expression of Talin1 and Integrin αvβ3 was measured in the receptive endometrium from the RIF (Recurrent implantation failure) cohort and NC (normal fertile control group) cohort. A JEG-3 trophoblast and endometrial epithelial cell adhesion model and pregnant mouse model were established. The molecular mechanism of Talin1-mediated cell adhesion was explored by RNA sequencing, RT-qPCR, as well as western blotting assays.

KEY FINDINGS

Talin1 enhances endometrial cell adhesion by regulating the Ras signaling pathway, and ultimately facilitates embryo implantation.

SIGNIFICANCE

This study revealed the molecular mechanisms of regarding the pathogenesis of RIF caused by endometrial receptivity insufficiency. Further pharmacological research on the Ras signaling pathway would be valuable and might provide new therapeutic targets for RIF patients.

Effects of Environmental Conditions on Nephron Number: Modeling Maternal Disease and Epigenetic Regulation in Renal Development

A growing body of evidence suggests that low nephron numbers at birth can increase the risk of chronic kidney disease or hypertension later in life. Environmental stressors, such as maternal malnutrition, medication and smoking, can influence renal size at birth. Using metanephric organ cultures to model single-variable environmental conditions, models of maternal disease were evaluated for patterns of developmental impairment. While hyperthermia had limited effects on renal development, fetal iron deficiency was associated with severe impairment of renal growth and nephrogenesis with an all-proximal phenotype. Culturing kidney explants under high glucose conditions led to cellular and transcriptomic changes resembling human diabetic nephropathy. Short-term high glucose culture conditions were sufficient for long-term alterations in DNA methylation-associated epigenetic memory. Finally, the role of epigenetic modifiers in renal development was tested using a small compound library. Among the selected epigenetic inhibitors, various compounds elicited an effect on renal growth, such as HDAC (entinostat, TH39), histone demethylase (deferasirox, deferoxamine) and histone methyltransferase (cyproheptadine) inhibitors. Thus, metanephric organ cultures provide a valuable system for studying metabolic conditions and a tool for screening for epigenetic modifiers in renal development.

A functional missense variant in ITIH3 affects protein expression and neurodevelopment and confers schizophrenia risk in the Han Chinese population

The Psychiatric Genomics Consortium (PGC) has recently identified 10 potential functional coding variants for schizophrenia. However, how these coding variants confer schizophrenia risk remains largely unknown. Here, we investigate the associations between eight potential functional coding variants identified by PGC and schizophrenia in a large Han Chinese sample (n = 4022 cases and 9270 controls). Among the eight tested single nucelotide polymorphisms (SNPs), rs3617 (a missense variant, p.K315Q in the ITIH3 gene) showed genome-wide significant association with schizophrenia in the Han Chinese population (P = 8.36 × 10^-16), with the same risk allele as in PGC. Interestingly, rs3617 is located in a genomic region that is highly evolutionarily conserved, and its schizophrenia risk allele (C allele) was associated with lower ITIH3 mRNA and protein expression. Intriguingly, mouse neural stem cells stably overexpressing ITIH3 with different alleles of rs3617 exhibited significant differences in proliferation, migration, and differentiation, suggesting the impact of rs3617 on neurodevelopment. Subsequent transcriptome analysis found that the differentially expressed genes in neural stem cells stably overexpressing different alleles of rs3617 were significantly enriched in schizophrenia-related pathways, including cell adhesion, synapse assembly, MAPK and PI3K-AKT pathways. Our study provides convergent lines of evidence suggesting that rs3617 in ITIH3 likely affects protein function and neurodevelopment and thereby confers risk of schizophrenia.

Neonatal hyperoxia depletes pulmonary vein cardiomyocytes in adult mice via mitochondrial oxidation

Supplemental oxygen given to preterm infants has been associated with permanently altering postnatal lung development. Now that these individuals are reaching adulthood, there is growing concern that early life oxygen exposure may also promote cardiovascular disease through poorly understood mechanisms. We previously reported that adult mice exposed to 100% oxygen between postnatal days 0 and 4 develop pulmonary hypertension, defined pathologically by capillary rarefaction, dilation of arterioles and veins, cardiac failure, and a reduced lifespan. Here, Affymetrix Gene Arrays are used to identify early transcriptional changes that take place in the lung before pulmonary capillary rarefaction. We discovered neonatal hyperoxia reduced expression of cardiac muscle genes, including those involved in contraction, calcium signaling, mitochondrial respiration, and vasodilation. Quantitative RT-PCR, immunohistochemistry, and genetic lineage mapping using Myh6^CreER; Rosa26^RmT/mG mice revealed this reflected loss of pulmonary vein cardiomyocytes. The greatest loss of cadiomyocytes was seen within the lung followed by a graded loss beginning at the hilum and extending into the left atrium. Loss of these cells was seen by 2 wk of age in mice exposed to ≥80% oxygen and was attributed, in part, to reduced proliferation. Administering mitoTEMPO, a scavenger of mitochondrial superoxide during neonatal hyperoxia prevented loss of these cells. Since pulmonary vein cardiomyocytes help pump oxygen-rich blood out of the lung, their early loss following neonatal hyperoxia may contribute to cardiovascular disease seen in these mice, and perhaps in people who were born preterm.

Review: Metabolic Control of Immune System Activation in Rheumatic Diseases

Metabolic pathways mediate lineage specification within the immune system through the regulation of glucose utilization, a process that generates energy in the form of ATP and synthesis of amino acids, nucleotides, and lipids to enable cell growth, proliferation, and survival. CD4+ T cells, a proinflammatory cell subset, preferentially produce ATP through glycolysis, whereas cells with an antiinflammatory lineage, such as memory and regulatory T cells, favor mitochondrial ATP generation. In conditions of metabolic stress or a shortage of nutrients, cells rely on autophagy to secure amino acids and other substrates, while survival depends on the sparing of mitochondria and maintenance of a reducing environment. The pentose phosphate pathway acts as a key gatekeeper of inflammation by supplying ribose‐5‐phosphate for cell proliferation and NADPH for antioxidant defenses. Increased lysosomal catabolism, accumulation of branched amino acids, glutamine, kynurenine, and histidine, and depletion of glutathione and cysteine activate the mechanistic target of rapamycin (mTOR), an arbiter of lineage development within the innate and adaptive immune systems. Mapping the impact of susceptibility genes to metabolic pathways allows for better understanding and therapeutic targeting of disease‐specific expansion of proinflammatory cells. Therapeutic approaches aimed at glutathione depletion and mTOR pathway activation appear to be safe and effective for treating lupus, while an opposing intervention may be of benefit in rheumatoid arthritis. Environmental sources of origin for metabolites within immune cells may include microbiota and plants. Thus, a better understanding of the pathways of immunometabolism could provide new insights into the pathogenesis and treatment of the rheumatic diseases.

How Mesp1 makes a move

The transcription factors Mesp1 and Mesp2 have essential roles in the migration and specification of multipotent progenitor cells at the onset of cardiogenesis. Chiapparo et al. (2016. J. Cell Biol http://dx.doi.org/10.1083/jcb.201505082) identify common Mesp functions in fate specification and Mesp1-specific targets controlling the speed and direction of progenitor cell migration.

Low concentrations of hydrogen peroxide or nitrite induced of Paracoccidioides brasiliensis cell proliferation in a Ras-dependent manner

Paracoccidioides brasiliensis, a causative agent of paracoccidioidomycosis (PCM), should be able to adapt to dramatic environmental changes inside the infected host after inhalation of air-borne conidia and transition to pathogenic yeasts. Proteins with antioxidant functions may protect fungal cells against reactive oxygen (ROS) and nitrogen (RNS) species generated by phagocytic cells, thus acting as potential virulence factors. Ras GTPases are involved in stress responses, cell morphology, and differentiation in a range of organisms. Ras, in its activated form, interacts with effector proteins and can initiate a kinase cascade. In lower eukaryotes, Byr2 kinase represents a Ras target. The present study investigated the role of Ras in P. brasiliensis after in vitro stimulus with ROS or RNS. We have demonstrated that low concentrations of H₂O₂ (0.1 mM) or NO₂ (0.1–0.25 µM) stimulated P. brasiliensis yeast cell proliferation and that was not observed when yeast cells were pre-incubated with farnesyltransferase inhibitor. We constructed an expression plasmid containing the Byr2 Ras-binding domain (RBD) fused with GST (RBD-Byr2-GST) to detect the Ras active form. After stimulation with low concentrations of H₂O₂ or NO₂, the Ras active form was observed in fungal extracts. Besides, NO₂ induced a rapid increase in S-nitrosylated Ras levels. This alternative posttranslational modification of Ras, probably in residue Cys123, would lead to an exchange of GDP for GTP and consequent GTPase activation in P. brasiliensis. In conclusion, low concentrations of H₂O₂ or NO₂ stimulated P. brasiliensis proliferation through Ras activation.

Pharmacological manipulation of blood and lymphatic vascularization in ex vivo-cultured mouse embryos

Formation of new blood and lymphatic vessels is involved in many physiological and pathological processes, including organ and tumor growth, cancer cell metastasis, fluid drainage and lymphedema. Therefore, the ability to manipulate vascularization in a mammalian system is of particular interest to researchers. Here we describe a method for pharmacological manipulation of de novo and sprouting blood and lymphatic vascular development in ex vivo-cultured mouse embryos. The described protocol can also be used to evaluate the properties of pharmacological agents in growing mammalian tissues and to manipulate other developmental processes. The whole procedure, from embryo isolation to image quantification, takes 3-5 d, depending on the analysis and age of the embryos.

Effects of β4 integrin expression on microRNA patterns in breast cancer

The integrin α6β4 is defined as an adhesion receptor for laminins. Referred to as ‘β4’, this integrin plays a key role in the progression of various carcinomas through its ability to orchestrate key signal transduction events and promote cell motility. To identify novel downstream effectors of β4 function in breast cancer, microRNAs (miRNAs) were examined because of their extensive links to tumorigenesis and their ability to regulate gene expression globally. Two breast carcinoma cell lines and a collection of invasive breast carcinomas with varying β4 expression were used to assess the effect of this integrin on miRNA expression. A novel miRNA microarray analysis termed quantitative Nuclease Protection Assay (qNPA) revealed that β4 expression can significantly alter miRNA expression and identified two miRNA families, miR-25/32/92abc/363/363-3p/367 and miR-99ab/100, that are consistently downregulated by expression of this integrin. Analysis of published Affymetrix GeneChip data identified 54 common targets of miR-92ab and miR-99ab/100 within the subset of β4-regulated mRNAs, revealing several genes known to be key components of β4-regulated signaling cascades and effectors of cell motility. Gene ontology classification identified an enrichment in genes associated with cell migration within this population. Finally, gene set enrichment analysis of all β4-regulated mRNAs revealed an enrichment in targets belonging to distinct miRNA families, including miR-92ab and others identified by our initial array analyses. The results obtained in this study provide the first example of an integrin globally impacting miRNA expression and provide evidence that select miRNA families collectively target genes important in executing β4-mediated cell motility.