Ephrin Signaling Research Articles

Large-scale proteomic profiling reveals characteristic HIV-specific druggable protein signatures associated with incident heart failure

Abstract Background Compared with the general population, persons with HIV suffer from an augmented risk of both systolic and diastolic heart failure despite effective antiretroviral therapy [1]. While inflammatory and coagulation markers are thought to be involved in this increased risk, other contributing mechanisms, such as pro-inflammatory protein networks, remain to be elucidated. Purpose To identify novel protein predictors of incident heart failure events in the longitudinal Veterans Aging Cohort Study Biomarker Cohort of United States Veterans with HIV (PLWH; n = 1525) and without HIV (PWoH; n = 853) and to assess the functional relatedness of these proteins in PLWH. Methods We characterized the plasma proteome of PLWH and PWoH using an aptamer-based platform and assessed univariable associations with incident heart failure. Druggable proteins were identified using the Therapeutic Target Database [2]. We built a protein interaction network querying significant proteins (q-value <0.05) using Cytoscape for the Retrieval of Interacting Genes/Proteins (STRING) database [3]. To focus on densely connected core proteins, we used the mcl clustering method and identified a subnetwork of approximately 77 proteins. Over-representation analysis was performed for the core network by identifying enriched gene sets using Gene Ontology biological processes and WikiPathways. Final results are filtered based on a false discovery rate (FDR) threshold of 0.05. Results Of 4926 plasma proteins, 441 proteins in all PLWH and 706 in those with well-controlled HIV (viral load <200 copies/mL) were significantly associated with incident heart failure, compared with only 142 among PWoH (Figure 1A). Of the top 50 proteins most significantly associated with heart failure, 21 were druggable in PLWH and 14 in PWoH; only 5 druggable markers were shared, while 16 were unique to HIV (Table 1). Pleiotrophin, a pro-angiogenic, pro-inflammatory cytokine that induces tumor necrosis factor- (TNF) α, interleukin- (IL) 1β, and IL-6 expression and has been implicated in cardiomyocyte apoptosis [4,5], had the highest hazard ratio (HR) for incident heart failure (HR = 4.7; p = 1.6E-20; q = 1.7E-18) in PLWH. The most significant enriched protein pathway included 36 genes involved in chemotaxis (FDR = 1.3E-30); 3 of the 21 druggable targets (pleiotrophin, ephrin-A5, and ephrin type-A receptor 2) were represented in this pathway (Figure 1B). Ephrin signaling pathways, which are involved in cell adhesion, differentiation, and proliferation [6], have not previously been implicated in heart failure, nor in HIV. Subnetwork analysis of druggable proteins demonstrated that ephrin-signaling, IL-15, and TNF pathways were functionally interconnected (Figure 1C). Conclusions Our findings indicate that there may be unique pro-inflammatory pathways characteristic of HIV-associated cardiomyopathy that merit further study as dedicated pharmacologic targets and/or risk markers in this population.

Ephrin Signaling and the Development of Early Progressive Kidney Function Decline

Ephrin Signaling and the Development of Early Progressive Kidney Function Decline

Comment on, "Increased expression of ephrin A1 in brain arteriovenous malformation: DNA microarray analysis".

This study by Sasahara et al. explores the role of ephrin A1 in brain arteriovenous malformations (AVM) using DNA microarray analysis, quantitative real-time RT-PCR, and immunohistochemistry. The research identifies significant upregulation of ephrin A1 in AVM, suggesting its potential involvement in the abnormal vascular architecture characteristic of this condition. The study's innovative methodology and thorough exploration of gene expression patterns contribute valuable insights into AVM pathogenesis, highlighting ephrin A1 as a potential therapeutic target. However, the study's limitations include clinical variability among patient samples and the use of draining veins as controls, which may affect the robustness of the findings. Future research should address these limitations by using more homogeneous samples and expanding the investigation to include other ephrin family members. This could provide a broader understanding of ephrin signaling in AVM and guide the development of targeted therapies.

N-phenyl pyrazoline derivative inhibits cell aggressiveness and enhances paclitaxel sensitivity of triple negative breast cancer cells

Protein kinase dysregulation induces cancer cell aggressiveness leading to rapid tumor progression and poor prognosis in TNBC patients. Many small-molecule kinase inhibitors have been tested in clinical trials to treat TNBC patients. In the previous study, we found that N-phenylpyrazoline small molecule acts as a protein kinase inhibitor in cervical cancer cells. However, there remains unknown about N-phenyl pyrazoline potency as a kinase inhibitor and its anti-cancer activity in TNBC cells. In this study, we investigated the activity of N-phenyl pyrazoline against TNBC cells via tyrosine kinase inhibition. Based on the MTT assay, the IC50 values for the N-phenyl pyrazoline 2, 5, A, B, C, and D against Hs578T were 12.63 µM, 3.95 µM, not available, 18.62 µM, 30.13 µM, and 26.79 µM, respectively. While only P5 exhibited the IC50 against MDA MB 231 (21.55 µM). Further, N-phenyl pyrazoline 5 treatment significantly inhibited the cell proliferation rate of Hs578T and MDA MB 231 cells. The migration assay showed that treatment with the compound N-phenyl pyrazoline 5 with 4 µM concentration significantly reduced cell migration of Hs578T cells. N-phenyl pyrazoline 5 treatment at 1 µM and 2 µM was able to reduce the tumorsphere size of Hs578t cells. A combination treatment of P5 and paclitaxel showed a synergistic effect with a combination index score > 1 in both TNBC cells. Further, the P5 predictively targeted the protein kinases that significantly correlated to breast cancer prognosis. The GSEA analysis result shows that receptor tyrosine kinase, Notch3, Notch4, and Ephrin signaling pathways were targeted by P5. The P5 treatment reduced the EGFR expression level and activation in TNBC cells.

Targeting ephrin signalling in sepsis.

Targeting ephrin signalling in sepsis.

Abstract 2846: Investigation of mechanisms that result in health disparity for Hispanic/Latino patients with B acute lymphoblastic leukemia

Abstract Although social determinants of health have a large impact on health disparity, biologic vulnerabilities - particularly in cancers that impact at-risk populations are important. Amongst children with Acute Lymphoblastic Leukemia (ALL), the Hispanic/Latino (H/L) population is vulnerable given since the risk of developing ALL is 1.2-1.75 that of Non-Hispanic White children. After corrections for socioeconomic impacts, the mortality for H/L children is 40% higher than NHW. H/L children have a higher rate of high-risk genetic variations: 2-fold rate of heterozygous IKZF1 deletion (IKZF1-del) and a 4-fold rate of CRLF2 translocation. IKZF1 deletion and CRLF2 translocations are associated increased risk of relapse and chemotherapy resistance in B ALL. IKZF1 is an important transcriptional factor and epigenetic regulator that affects global gene transcription in hematopoietic cells. Simultaneous IKZF1-del and CRLF2 translocation represented 94% of H/L children with CRLF2 translocation. Although only 49% of all H/L patients with IKZF1-del had a CRLF2 translocation. Transcriptomics were analyzed for 42 H/L and 18 NHW patient samples using RNAseq. Gene expression from H/L patients was compared to expression in NHW patients and differentially expressed genes were analyzed. Gene set enrichment analysis (GSEA) revealed downregulation of processes responsible for genome maintenance including DNA replication, DNA templated transcription elongation, double strand break repair, and recombinational repair. Ingenuity pathway analysis (IPA) revealed upregulated pathways in stress related translation, histone deacetylases, interferon, and FLT3 signaling compared to NWH. H/L specimens resulted in decreased expression for FGF pathways, ceramide, and FAK signaling. We performed the same analysis in H/L and NHW with wildtype IKZF1 to compare these two population without high risk structural variants. GSEA analysis showed downregulated Intra S DNA Damage checkpoint signaling, DNA replication checkpoint signaling, glutamine amino acid synthesis, and aspartate amino acid synthesis. IPA showed upregulated interferon, histone deacetylases, TREM1 signaling, and Tec Kinase signaling. IPA showed downregulated Ephrin and CDK5 signaling. DNA methylation patterns were compared between 8 H/L and 8 NWH B ALL samples which showed differential methylation patterns affecting multiple cancer relevant genes.In conclusion, these data represent biologic vulnerability in H/L patients with B ALL in comparison to NWH regardless of high-risk genetic variants. H/L B-ALL shows deregulated maintenance of the genome via replication and repair pathways as well as potential vulnerabilities related to regulation of glutamate/aspartate synthesis. These findings give insight into potential mechanisms that can explain increased frequency of high-risk genetic variants in H/L B ALL. Citation Format: Joseph W. Schramm, Bing He, Yali Ding, Chingakham Singh, Daniel Bogush, Katarina Dovat, Diwakar Bastihalli Tukaramrao, Riya Bhalodia, Sinisa Dovat. Investigation of mechanisms that result in health disparity for Hispanic/Latino patients with B acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2846.

Long-term impact of maternal obesity on the gliovascular unit and ephrin signaling in the hippocampus of adult offspring.

Children born to obese mothers are at increased risk of developing mood disorders and cognitive impairment. Experimental studies have reported structural changes in the brain such as the gliovascular unit as well as activation of neuroinflammatory cells as a part of neuroinflammation processing in aged offspring of obese mothers. However, the molecular mechanisms linking maternal obesity to poor neurodevelopmental outcomes are not well established. The ephrin system plays a major role in a variety of cellular processes including cell-cell interaction, synaptic plasticity, and long-term potentiation. Therefore, in this study we determined the impact of maternal obesity in pregnancy on cortical, hippocampal development, vasculature and ephrin-A3/EphA4-signaling, in the adult offspring in mice. Maternal obesity was induced in mice by a high fat/high sugar Western type of diet (HF/HS). We collected brain tissue (prefrontal cortex and hippocampus) from 6-month-old offspring of obese and lean (control) dams. Hippocampal volume, cortical thickness, myelination of white matter, density of astrocytes and microglia in relation to their activity were analyzed using 3-D stereological quantification. mRNA expression of ephrin-A3, EphA4 andsynaptic markers were measured by qPCR in the brain tissue. Moreover, expression of gap junction protein connexin-43, lipocalin-2, and vascular CD31/Aquaporin 4 were determined in the hippocampus by immunohistochemistry. Volume of hippocampus and cortical thickness were significantly smaller, and myelination impaired, while mRNA levels of hippocampal EphA4 and post-synaptic density (PSD) 95 were significantly lower in the hippocampus in the offspring of obese dams as compared to offspring of controls. Further analysis of the hippocampal gliovascular unit indicated higher coverage of capillaries by astrocytic end-feet, expression of connexin-43 and lipocalin-2 in endothelial cells in the offspring of obese dams. In addition, offspring of obese dams demonstrated activation of microglia together with higher density of cells, while astrocyte cell density was lower. Maternal obesity affects brain size, impairs myelination, disrupts the hippocampal gliovascular unit and decreases the mRNA expression of EphA4 and PSD-95 in the hippocampus of adult offspring. These results indicate that the vasculature-glia cross-talk may be an important mediator of altered synaptic plasticity, which could be a link between maternal obesity and neurodevelopmental/neuropsychiatric disorders in the offspring.

Homeostatic Regulation of Pro-Angiogenic and Anti-Angiogenic Proteins via Hedgehog, Notch Grid, and Ephrin Signaling in Tibial Dyschondroplasia.

Precise coupling of two fundamental mechanisms, chondrogenesis and osteogenesis via angiogenesis, plays a crucial role during rapid proliferation of growth plates, and alteration in their balance might lead to pathogenic conditions. Tibial dyschondroplasia (TD) is characterized by an avascular, non-mineralized, jade-white "cartilaginous wedge" with impaired endochondral ossification and chondrocyte proliferation at the proximal end of a tibial bone in rapidly growing poultry birds. Developing vascular structures are dynamic with cartilage growth and are regulated through homeostatic balance among pro and anti-angiogenic proteins and cytokines. Pro-angiogenic factors involves a wide spectrum of multifactorial mitogens, such as vascular endothelial growth factors (VEGF), platelet-derived growth factors (PDGF), basic fibroblast growth factor (bFGF), placental growth factors, transforming growth factor-β (TGF-β), and TNF-α. Considering their regulatory role via the sonic hedgehog, notch-gridlock, and ephrin-B2/EphB4 pathways and inhibition through anti-angiogenic proteins like angiostatin, endostatin, decoy receptors, vasoinhibin, thrombospondin, PEX, and troponin, their possible role in persisting inflammatory conditions like TD was studied in the current literature review. Balanced apoptosis and angiogenesis are vital for physiological bone growth. Any homeostatic imbalance among apoptotic, angiogenetic, pro-angiogenic, or anti-angiogenic proteins ultimately leads to pathological bone conditions like TD and osteoarthritis. The current review might substantiate solid grounds for developing innovative therapeutics for diseases governed by the disproportion of angiogenesis and anti-angiogenesis proteins.

The long non-coding RNA TAZ-AS202 promotes lung cancer progression via regulation of the E2F1 transcription factor and activation of Ephrin signaling

Long non-coding RNAs (lncRNAs) are transcripts without coding potential that are pervasively expressed from the genome and have been increasingly reported to play crucial roles in all aspects of cell biology. They have been also heavily implicated in cancer development and progression, with both oncogenic and tumor suppressor functions. In this work, we identified and characterized a novel lncRNA, TAZ-AS202, expressed from the TAZ genomic locus and exerting pro-oncogenic functions in non-small cell lung cancer. TAZ-AS202 expression is under the control of YAP/TAZ-containing transcriptional complexes. We demonstrated that TAZ-AS202 is overexpressed in lung cancer tissue, compared with surrounding lung epithelium. In lung cancer cell lines TAZ-AS202 promotes cell migration and cell invasion. TAZ-AS202 regulates the expression of a set of genes belonging to cancer-associated pathways, including WNT and EPH-Ephrin signaling. The molecular mechanism underlying TAZ-AS202 function does not involve change of TAZ expression or activity, but increases the protein level of the transcription factor E2F1, which in turn regulates the expression of a large set of target genes, including the EPHB2 receptor. Notably, the silencing of both E2F1 and EPHB2 recapitulates TAZ-AS202 silencing cellular phenotype, indicating that they are essential mediators of its activity. Overall, this work unveiled a new regulatory mechanism that, by increasing E2F1 protein, modifies the non-small cell lung cancer cells transcriptional program, leading to enhanced aggressiveness features. The TAZ-AS202/E2F1/EPHB2 axis may be the target for new therapeutic strategies.

Abstract 15132: Proteomic Signatures of Human Immunodeficiency Virus-Associated Subclinical Left Atrial Dilation

Introduction: Persons living with HIV (PLWH) receiving combination antiretroviral therapy (cART) are at higher risk of heart failure (HF) and preceding cardiac abnormalities, including left atrial (LA) dilation, compared to persons without HIV (PWOH). Mechanisms of this excess risk are unclear. We assessed whether plasma proteomic signatures of immune activation are cross-sectionally associated with LA volume index (LAVi) and augmented among PLWH. Methods: We performed Olink proteomics on plasma obtained concurrently with cardiac magnetic resonance among PLWH and PWOH. Proteins were analyzed individually and as clusters agnostically defined using weighted gene co-expression network analysis. Associations with HIV serostatus and LAVi were estimated using multivariable linear regression with robust variance. We explored protein relationships using annotated enrichment analysis. Results: Among 352 participants (age 55±6 years; 25% female; 70% Black), mean LAVi was 29±9 mL/m 2 and 60% were PLWH (88% on cART; 73% with undetectable plasma HIV RNA). Of 2594 proteins, 104 were independently associated with LAVi (false discovery rate, FDR<0.05). We identified 49 of these as candidate contributors to the association between HIV seropositivity and higher LAVi (36 when excluding PLWH with detectable HIV RNA), enriched in T-cell activation and leukocyte cell adhesion regulators. We identified one protein cluster positively associated with LAVi and HIV seropositivity regardless of HIV suppression status, enriched in TNF signaling, ephrin signaling and extracellular matrix (ECM) organization. Conclusion: Proteomic signatures that may in part account for HIV-associated elevation in LAVi are enriched in pathways of immune activation, cytokine signaling and ECM organization, even among virally suppressed PLWH on cART. These findings support a link between persistent immune activation and subclinical LA dilation which may portend future risk for HF among PLWH.

Proteomics of CKD progression in the chronic renal insufficiency cohort

Progression of chronic kidney disease (CKD) portends myriad complications, including kidney failure. In this study, we analyze associations of 4638 plasma proteins among 3235 participants of the Chronic Renal Insufficiency Cohort Study with the primary outcome of 50% decline in estimated glomerular filtration rate or kidney failure over 10 years. We validate key findings in the Atherosclerosis Risk in the Communities study. We identify 100 circulating proteins that are associated with the primary outcome after multivariable adjustment, using a Bonferroni statistical threshold of significance. Individual protein associations and biological pathway analyses highlight the roles of bone morphogenetic proteins, ephrin signaling, and prothrombin activation. A 65-protein risk model for the primary outcome has excellent discrimination (C-statistic[95%CI] 0.862 [0.835, 0.889]), and 14/65 proteins are druggable targets. Potentially causal associations for five proteins, to our knowledge not previously reported, are supported by Mendelian randomization: EGFL9, LRP-11, MXRA7, IL-1 sRII and ILT-2. Modifiable protein risk markers can guide therapeutic drug development aimed at slowing CKD progression.

Activation of multiple Eph receptors on neuronal membranes correlates with the onset of optic neuropathy

BackgroundOptic neuropathy is a major cause of irreversible blindness, yet the molecular determinants that contribute to neuronal demise have not been fully elucidated. Several studies have identified ‘ephrin signaling’ as one of the most dysregulated pathways in the early pathophysiology of optic neuropathy with varied etiologies. Developmentally, gradients in ephrin signaling coordinate retinotopic mapping via repulsive modulation of cytoskeletal dynamics in neuronal membranes. Little is known about the role ephrin signaling plays in the post-natal visual system and its correlation with the onset of optic neuropathy.MethodsPostnatal mouse retinas were collected for mass spectrometry analysis for erythropoietin-producing human hepatocellular (Eph) receptors. Optic nerve crush (ONC) model was employed to induce optic neuropathy, and proteomic changes during the acute phase of neuropathic onset were analyzed. Confocal and super-resolution microscopy determined the cellular localization of activated Eph receptors after ONC injury. Eph receptor inhibitors assessed the neuroprotective effect of ephrin signaling modulation.ResultsMass spectrometry revealed expression of seven Eph receptors (EphA2, A4, A5, B1, B2, B3, and B6) in postnatal mouse retinal tissue. Immunoblotting analysis indicated a significant increase in phosphorylation of these Eph receptors 48 h after ONC. Confocal microscopy demonstrated the presence of both subclasses of Eph receptors within the retina. Stochastic optical reconstruction microscopy (STORM) super-resolution imaging combined with optimal transport colocalization analysis revealed a significant co-localization of activated Eph receptors with injured neuronal cells, compared to uninjured neuronal and/or injured glial cells, 48 h post-ONC. Eph receptor inhibitors displayed notable neuroprotective effects for retinal ganglion cells (RGCs) after six days of ONC injury.ConclusionsOur findings demonstrate the functional presence of diverse Eph receptors in the postnatal mammalian retina, capable of modulating multiple biological processes. Pan-Eph receptor activation contributes to the onset of neuropathy in optic neuropathies, with preferential activation of Eph receptors on neuronal processes in the inner retina following optic nerve injury. Notably, Eph receptor activation precedes neuronal loss. We observed a neuroprotective effect on RGCs upon inhibiting Eph receptors. Our study highlights the importance of investigating this repulsive pathway in early optic neuropathies and provides a comprehensive characterization of the receptors present in the developed retina of mice, relevant to both homeostasis and disease processes.

2393P Ephrin signalling mediates resistance to programmed death ligand 1 (PD-L1) inhibition in urothelial carcinoma (UC)

2393P Ephrin signalling mediates resistance to programmed death ligand 1 (PD-L1) inhibition in urothelial carcinoma (UC)

Cross-phyla protein annotation by structural prediction and alignment

BackgroundProtein annotation is a major goal in molecular biology, yet experimentally determined knowledge is typically limited to a few model organisms. In non-model species, the sequence-based prediction of gene orthology can be used to infer protein identity; however, this approach loses predictive power at longer evolutionary distances. Here we propose a workflow for protein annotation using structural similarity, exploiting the fact that similar protein structures often reflect homology and are more conserved than protein sequences.ResultsWe propose a workflow of openly available tools for the functional annotation of proteins via structural similarity (MorF: MorphologFinder) and use it to annotate the complete proteome of a sponge. Sponges are highly relevant for inferring the early history of animals, yet their proteomes remain sparsely annotated. MorF accurately predicts the functions of proteins with known homology in >90%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${>}90\\%$$\\end{document} cases and annotates an additional 50%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$50\\%$$\\end{document} of the proteome beyond standard sequence-based methods. We uncover new functions for sponge cell types, including extensive FGF, TGF, and Ephrin signaling in sponge epithelia, and redox metabolism and control in myopeptidocytes. Notably, we also annotate genes specific to the enigmatic sponge mesocytes, proposing they function to digest cell walls.ConclusionsOur work demonstrates that structural similarity is a powerful approach that complements and extends sequence similarity searches to identify homologous proteins over long evolutionary distances. We anticipate this will be a powerful approach that boosts discovery in numerous -omics datasets, especially for non-model organisms.

Alterations in the Circulating Proteome Associated with Albuminuria.

We describe circulating proteins associated with albuminuria in a population of African American Study of Kidney Disease and Hypertension with CKD (AASK) using the largest proteomic platform to date: nearly 7000 circulating proteins, representing approximately 2000 new targets. Findings were replicated in a subset of a general population cohort with kidney disease (ARIC) and a population with CKD Chronic Renal Insufficiency Cohort (CRIC). In cross-sectional analysis, 104 proteins were significantly associated with albuminuria in the Black group, of which 67 of 77 available proteins were replicated in ARIC and 68 of 71 available proteins in CRIC. LMAN2, TNFSFR1B, and members of the ephrin superfamily had the strongest associations. Pathway analysis also demonstrated enrichment of ephrin family proteins. Proteomic techniques have facilitated understanding of pathways that mediate decline in GFR. Albuminuria is a key component of CKD diagnosis, staging, and prognosis but has been less studied than GFR. We sought to investigate circulating proteins associated with higher albuminuria. We evaluated the cross-sectional associations of the blood proteome with albuminuria and longitudinally with doubling of albuminuria in the African American Study of Kidney Disease and Hypertension (AASK; 38% female; mean GFR 46; median urine protein-to-creatinine ratio 81 mg/g; n =703) and replicated in two external cohorts: a subset of the Atherosclerosis Risk in Communities (ARIC) study with CKD and the Chronic Renal Insufficiency Cohort (CRIC). In cross-sectional analysis, 104 proteins were significantly associated with albuminuria in AASK, of which 67 of 77 available proteins were replicated in ARIC and 68 of 71 available proteins in CRIC. Proteins with the strongest associations included LMAN2, TNFSFR1B, and members of the ephrin superfamily. Pathway analysis also demonstrated enrichment of ephrin family proteins. Five proteins were significantly associated with worsening albuminuria in AASK, including LMAN2 and EFNA4, which were replicated in ARIC and CRIC. Among individuals with CKD, large-scale proteomic analysis identified known and novel proteins associated with albuminuria and suggested a role for ephrin signaling in albuminuria progression.

Research progress on the modulation mechanism of electroacupuncture for learning and memory impairment after ischemic stroke

Electroacupuncture may play a role in treatment of learning and memory impairment after ischemic stroke by regulating phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA)/cAMP response element binding protein (CREB) signaling pathway, nerve growth factor (NGF)/tyrosine kinase-A (TrkA) signaling pathway, Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway, Notch signaling pathway, erythropoietin-producing hepatocyte (Eph)/ephrin signaling pathway. The interactions among these pathways should be further explored in treatment of learning and memory impairment after ischemic stroke.

Folding the neural plate.

Apical constriction and neural tube closure depend on coordinated ephrin and Wnt signaling.

Identification of ocular regulatory functions of core histone variant H3.2

The posttranscriptional modifications (PTM) of the Histone H3 family play an important role in ocular system differentiation. However, there has been no study on the nature of specific Histone H3 subtype carrying these modifications. Fortuitously, we had previously identified a dominant small-eye mutant Aey69 mouse with a mutation in the H3.2 encoding Hist2h3c1 gene (Vetrivel et al., 2019). In continuation, in the present study, the role of Histone H3.2 with relation to the microphtalmic Aey69 has been elaborated. Foremost, a transgenic mouse line expressing the fusion protein H3.2-GFP was generated using Crispr/Cas9. The approach was intended to confer a unique tag to the Hist2h3c1 gene which is similar in sequence and encoded protein structure to other histones. The GFP tag was then used for ChIP Seq analysis of the genes regulated by H3.2. The approach revealed ocular specific H3.2 targets including Ephrin family genes. Altered enrichment of H3.2 was found in the mutant Aey69 mouse, specifically around the ligand Efna5 and the receptor Ephb2. The effect of this altered enrichment on Ephrin signaling was further analysed by QPCR and immunohistochemistry. This study identifies Hist2h3c1 encoded H3.2 as an important epigenetic player in ocular development. By binding to specific regions of ocular developmental factors Histone H3.2 facilitates the function of these genes for successful early ocular development.

Axon Guidance Molecules and Pain

Chronic pain is a debilitating condition that influences the social, economic, and psychological aspects of patients’ lives. Hence, the need for better treatment is drawing extensive interest from the research community. Developmental molecules such as Wnt, ephrins, and semaphorins are acknowledged as central players in the proper growth of a biological system. Their receptors and ligands are expressed in a wide variety in both neurons and glial cells, which are implicated in pain development, maintenance, and resolution. Thereby, it is not surprising that the impairment of those pathways affects the activities and functions of the entire cell. Evidence indicates aberrant activation of their pathways in the nervous system in rodent models of chronic pain. In those conditions, Wnt, ephrin, and semaphorin signaling participate in enhancing neuronal excitability, peripheral sensitization, synaptic plasticity, and the production and release of inflammatory cytokines. This review summarizes the current knowledge on three main developmental pathways and their mechanisms linked with the pathogenesis and progression of pain, considering their impacts on neuronal and glial cells in experimental animal models. Elucidations of the downstream pathways may provide a new mechanism for the involvement of Wnt, ephrin, and semaphorin pathways in pain chronicity.

Deficiency of the bZIP transcription factors Mafg and Mafk causes misexpression of genes in distinct pathways and results in lens embryonic developmental defects.

Deficiency of the small Maf proteins Mafg and Mafk cause multiple defects, namely, progressive neuronal degeneration, cataract, thrombocytopenia and mid-gestational/perinatal lethality. Previous data shows Mafg −/−:Mafk +/- compound knockout (KO) mice exhibit cataracts age 4-months onward. Strikingly, Mafg −/−:Mafk −/− double KO mice develop lens defects significantly early in life, during embryogenesis, but the pathobiology of these defects is unknown, and is addressed here. At embryonic day (E)16.5, the epithelium of lens in Mafg −/−:Mafk −/− animals appears abnormally multilayered as demonstrated by E-cadherin and nuclear staining. Additionally, Mafg −/−:Mafk −/− lenses exhibit abnormal distribution of F-actin near the “fulcrum” region where epithelial cells undergo apical constriction prior to elongation and reorientation as early differentiating fiber cells. To identify the underlying molecular changes, we performed high-throughput RNA-sequencing of E16.5 Mafg −/−:Mafk −/− lenses and identified a cohort of differentially expressed genes that were further prioritized using stringent filtering criteria and validated by RT-qPCR. Several key factors associated with the cytoskeleton, cell cycle or extracellular matrix (e.g., Cdk1, Cdkn1c, Camsap1, Col3a1, Map3k12, Sipa1l1) were mis-expressed in Mafg −/−:Mafk −/− lenses. Further, the congenital cataract-linked extracellular matrix peroxidase Pxdn was significantly overexpressed in Mafg −/−:Mafk −/− lenses, which may cause abnormal cell morphology. These data also identified the ephrin signaling receptor Epha5 to be reduced in Mafg −/−:Mafk −/− lenses. This likely contributes to the Mafg −/−:Mafk −/− multilayered lens epithelium pathology, as loss of an ephrin ligand, Efna5 (ephrin-A5), causes similar lens defects. Together, these findings uncover a novel early function of Mafg and Mafk in lens development and identify their new downstream regulatory relationships with key cellular factors.