Plexin C1 influences immune response to intracellular LPS and survival in murine sepsis

BACKGROUND

Intracellular sensing of lipopolysaccharide (LPS) is essential for the immune response against gram-negative bacteria and results in activation of caspase-11 and pyroptotic cell death with fatal consequences in sepsis. We found the neuronal guidance receptor plexin C1 (PLXNC1) influences the intracellular response to LPS.

METHODS

We employed a murine model of sepsis via cecal ligation and binding (CLP), using PLXNC1-/- mice and littermate controls, and additionally transfected murine bone-marrow-derived macrophages (BMDMs) from both genotypes with LPS to achieve activation of the noncanonical inflammasome ex vivo. Additionally, we transfected the PLXNC1 ligand SL4c-d in vivo and ex vivo to examine its effect on intracellular LPS response.

RESULTS

We found the neuronal guidance receptor PLXNC1 dampens the intracellular response to LPS by interacting with adenylate cyclase 4 (ADCY4) and protein kinase A activity, which in turn diminishes caspase-11 expression. The absence of PLXNC1 results in excessive inflammation marked by increased cytokine release, increased secondary organ injury and reduced sepsis survival in a murine sepsis model induced by CLP. Notably, administration of SL4c-d-peptide ligand of PLXNC1-reduces the inflammatory response during CLP-induced sepsis and improves survival.

CONCLUSIONS

These results elucidate a previously unknown mechanism for PLXNC1 suppressing excessive noncanonical inflammasome activity and offer a new potential target for treatment of sepsis with its detrimental effects.

Unsupervised Analysis Reveals the Involvement of Key Immune Response Genes and the Matrisome in Resistance to BRAF and MEK Inhibitors in Melanoma

Melanoma tumors exhibit a wide range of heterogeneity in genomics even with shared mutations in the MAPK pathway, including BRAF mutations. Consistently, adaptive drug resistance to BRAF inhibitors and/or BRAF plus MEK inhibitors also exhibits a wide range of heterogeneous responses, which poses an obstacle for discovering common genes and pathways that can be used in clinic for overcoming drug resistance. This study objectively analyzed two sets of previously published tumor genomics data comparing pre-treated melanoma tumors and BRAFi- and/or MEKi-resistant tumors. Heterogeneity in response to BRAFi and BRAFi/MEKi was evident because the pre-treated tumors and resistant tumors did not exhibit a tendency of clustering together. Differentially expressed gene (DEG) analysis revealed eight genes and two related enriched signature gene sets (matrisome and matrisome-associated signature gene sets) shared by both sets of data. The matrisome was closely related to the tumor microenvironment and immune response, and five out of the eight shared genes were also related to immune response. The PLXNC1 gene links the shared gene set and the enriched signature gene sets as it presented in all analysis results. As the PLXNC1 gene was up-regulated in the resistant tumors, we validated the up-regulation of this gene in a laboratory using vemurafenib-resistant cell lines. Given its role in promoting inflammation, this study suggests that resistant tumors exhibit an inflammatory tumor microenvironment. The involvement of the matrisome and the specific set of immune genes identified in this study may provide new opportunities for developing future therapeutic methods.

Semaphorin 7A coordinates neutrophil response during pulmonary inflammation and sepsis

ABSTRACT

Pulmonary defense mechanisms are critical for host integrity during pneumonia and sepsis. This defense is fundamentally dependent on the activation of neutrophils during the innate immune response. Recent work has shown that semaphorin 7A (Sema7A) holds significant impact on platelet function, yet its role on neutrophil function within the lung is not well understood. This study aimed to identify the role of Sema7A during pulmonary inflammation and sepsis. In patients with acute respiratory distress syndrome (ARDS), we were able to show a correlation between Sema7A and oxygenation levels. During subsequent workup, we found that Sema7A binds to the neutrophil PlexinC1 receptor, increasing integrins, and L-selectin on neutrophils. Sema7A prompted neutrophil chemotaxis in vitro and the formation of platelet-neutrophil complexes in vivo. We also observed altered adhesion and transmigration of neutrophils in Sema7A-/-animals in the lung during pulmonary inflammation. This effect resulted in increased number of neutrophils in the interstitial space of Sema7A-/- animals but reduced numbers of neutrophils in the alveolar space during pulmonary sepsis. This finding was associated with significantly worse outcome of Sema7A-/- animals in a model of pulmonary sepsis. Sema7A has an immunomodulatory effect in the lung, affecting pulmonary sepsis and ARDS. This effect influences the response of neutrophils to external aggression and might influence patient outcome. This trial was registered at www.ClinicalTrials.gov as #NCT02692118.

Novel breast cancer susceptibility loci under linkage peaks identified in African ancestry consortia

BACKGROUND

Expansion of genome-wide association studies across population groups is needed to improve our understanding of shared and unique genetic contributions to breast cancer. We performed association and replication studies guided by a priori linkage findings from African ancestry (AA) relative pairs.

METHODS

We performed fixed-effect inverse-variance weighted meta-analysis under three significant AA breast cancer linkage peaks (3q26-27, 12q22-23, and 16q21-22) in 9241 AA cases and 10 193 AA controls. We examined associations with overall breast cancer as well as estrogen receptor (ER)-positive and negative subtypes (193,132 SNPs). We replicated associations in the African-ancestry Breast Cancer Genetic Consortium (AABCG).

RESULTS

In AA women, we identified two associations on chr12q for overall breast cancer (rs1420647, OR = 1.15, p = 2.50×10-6; rs12322371, OR = 1.14, p = 3.15×10-6), and one for ER-negative breast cancer (rs77006600, OR = 1.67, p = 3.51×10-6). On chr3, we identified two associations with ER-negative disease (rs184090918, OR = 3.70, p = 1.23×10-5; rs76959804, OR = 3.57, p = 1.77×10-5) and on chr16q we identified an association with ER-negative disease (rs34147411, OR = 1.62, p = 8.82×10-6). In the replication study, the chr3 associations were significant and effect sizes were larger (rs184090918, OR: 6.66, 95% CI: 1.43, 31.01; rs76959804, OR: 5.24, 95% CI: 1.70, 16.16).

CONCLUSION

The two chr3 SNPs are upstream to open chromatin ENSR00000710716, a regulatory feature that is actively regulated in mammary tissues, providing evidence that variants in this chr3 region may have a regulatory role in our target organ. Our study provides support for breast cancer variant discovery using prioritization based on linkage evidence.

PLXNC1 interference alleviates the inflammatory injury, apoptosis and extracellular matrix degradation of IL-1β-exposed chondrocytes via suppressing GRP78 expression

BACKGROUND

Osteoarthritis (OA) is a frequently encountered debilitating joint disorder. Whether plexin C1 (PLXNC1) is implicated in OA is far from being investigated despite its well-documented pro-inflammatory property in human diseases. The goal of this study is to expound the specific role of PLXNC1 in OA and elaborate the probable action mechanism.

METHODS

Firstly, PLXNC1 expression in the cartilage tissues of patients with OA was examined with GEO database. In interleukin-1beta (IL-1β)-induced OA cell model, RT-qPCR and western blotting tested the expression of PLXNC1, glucose-regulating protein 78 (GRP78) and extracellular matrix (ECM) degradation-related factors. Cell viability and inflammation were respectively judged by CCK-8 assay and RT-qPCR. TUNEL and western blotting estimated cell apoptosis. The potential binding between PLXNC1 and GRP78 was corroborated by Co-IP assay. Western blotting also tested the expression of endoplasmic reticulum stress (ERS)-associated proteins.

RESULTS

As it turned out, PLXNC1 expression was elevated in the cartilage tissues of patients with OA and IL-1β-treated chondrocytes. When PLXNC1 was depleted, the viability injury, inflammation, apoptosis and ECM degradation of chondrocytes exposed to IL-1β were obstructed. Besides, GRP78 bond to PLXNC1 in IL-1β-treated chondrocytes. The ascending GRP78 expression in the chondrocytes exposed to IL-1β was depleted after PLXNC1 was silenced. Meanwhile, the impacts of PLXNC1 deficiency on the viability, inflammatory response, apoptosis, ECM degradation as well as ERS in IL-1β-exposed chondrocytes were abolished by GRP78 up-regulation.

CONCLUSION

In summary, PLXNC1 silencing might interact with and down-regulate GRP78 to mitigate the apoptosis, inflammation, and ECM degradation of IL-1β-insulted chondrocytes in OA.

Targeting the Semaphorin3E-plexinD1 complex in allergic asthma

Asthma is a heterogenous airway disease characterized by airway inflammation and remodeling. It affects more than 300 million people worldwide and poses a significant burden on society. Semaphorins, discovered initially as neural guidance molecules, are ubiquitously expressed in various organs and regulate multiple signaling pathways. Interestingly, Semaphorin3E is a critical molecule in lung pathophysiology through its role in both lung development and homeostasis. Semaphorin3E binds to plexinD1, mediating regulatory effects on cell migration, proliferation, and angiogenesis. Recent in vitro and in vivo studies have demonstrated that the Semaphorin3E-plexinD1 axis is implicated in asthma, impacting inflammatory and structural cells associated with airway inflammation, tissue remodeling, and airway hyperresponsiveness. This review details the Semaphorin3E-plexinD1 axis in various aspects of asthma and highlights future directions in research including its potential role as a therapeutic target in airway allergic diseases.

MicroRNA expression in apical periodontitis and pulpal inflammation: a systematic review

Background

The aim of this systematic review is to determine microRNAs (miRs) that are differently expressed between diseased pulpal and periapical tissues.

Design

This systematic review used PubMed, Scopus, EBSCO, ProQuest, Cochrane database as well as manual searching to extract studies from January 2012 up to February 2022.

Results

A total of 12 studies met the eligibility criteria were included. All selected studies were of case-control type. Twenty-four miRNAs associated with apical periodontitis, 11 were found to be upregulatedand 13 were downregulated. Four out of the 44 miRs associated with pulpal inflammation were upregulated, whereas forty were downregulated. Six miRs, namely hsa-miR-181b, hsa-miR-181c,hsa-miR-455-3p,hsa-miR-128-3p, hsa-miR199a-5p, and hsa-miR-95, exhibited considerable downregulation in both periapical and pulp tissues.

Conclusion

MiRs have been investigated for their role in pulpal and periapical biology and may be utilised in diagnostic and therapeutic purposes. Further investigations are required to determine why certain irreversible pulpitis situations progress to apical periodontitis and others do not, based on the various miR expressions. Moreover, clinical and laboratory trials are needed to support this theory.

Subtyping based on immune cell fractions reveal heterogeneity of cardiac fibrosis in end-stage heart failure

Background

A central issue hindering the development of effective anti-fibrosis drugs for heart failure is the unclear interrelationship between fibrosis and the immune cells. This study aims at providing precise subtyping of heart failure based on immune cell fractions, elaborating their differences in fibrotic mechanisms, and proposing a biomarker panel for evaluating intrinsic features of patients' physiological statuses through subtype classification, thereby promoting the precision medicine for cardiac fibrosis.

Methods

We inferred immune cell type abundance of the ventricular samples by a computational method (CIBERSORTx) based on ventricular tissue samples from 103 patients with heart failure, and applied K-means clustering to divide patients into two subtypes based on their immune cell type abundance. We also designed a novel analytic strategy: Large-Scale Functional Score and Association Analysis (LAFSAA), to study fibrotic mechanisms in the two subtypes.

Results

Two subtypes of immune cell fractions: pro-inflammatory and pro-remodeling subtypes, were identified. LAFSAA identified 11 subtype-specific pro-fibrotic functional gene sets as the basis for personalised targeted treatments. Based on feature selection, a 30-gene biomarker panel (ImmunCard30) established for diagnosing patient subtypes achieved high classification performance, with the area under the receiver operator characteristic curve corresponding to 0.954 and 0.803 for the discovery and validation sets, respectively.

Conclusion

Patients with the two subtypes of cardiac immune cell fractions were likely having different fibrotic mechanisms. Patients' subtypes can be predicted based on the ImmunCard30 biomarker panel. We envision that our unique stratification strategy revealed in this study will unravel advance diagnostic techniques for personalised anti-fibrotic therapy.

MicroRNA Expression Profile in TSC Cell Lines and the Impact of mTOR Inhibitor

The aim of this study was to assess the potential implication of microRNA on tuberous sclerosis (TSC) pathogenesis by performing microRNA profiling on cell lines silencing TSC1 or TSC2 genes using qPCR panels, before and after incubation with rapamycin. Significant differences in expression were observed between samples before and after rapamycin treatment in nineteen miRNAs in TSC1, five miRNAs in TSC2 and seven miRNAs in controls. Of miRNAs dysregulated before rapamycin treatment, three normalized after treatment in the TSC1 group (miR-21-3p, miR-433-3p, let-7g-3p) and one normalized in the TSC2 group (miR-1224-3p). Of the miRNAs dysregulated before rapamycin treatment in the TSC1 and TSC2 groups, two did not normalize after treatment (miR-33a-3p, miR-29a-3p). The results of the possible targets indicated that there are four common genes with seed regions susceptible to regulation by those miRNAs: ZBTB20, PHACTR2, PLXNC1 and ATP1B4. Our data show no changes in mRNA expression of these targets after rapamycin treatment. In conclusion, results of our study indicate the involvement of miRNA dysregulation in the pathogenesis of TSC. Some of the miRNA might be used as markers of treatment efficacy and autonomic miRNA as a target for future therapy.

An IDO1-related immune gene signature predicts overall survival in acute myeloid leukemia

The semaphorin receptor PLXNC1 is an IDO1-interacting gene and a strong predictor of survival in AML.

An IDO1-related immune gene signature, including PLXNC1, predicts survival in AML.

The contribution of the bone marrow (BM) immune microenvironment to acute myeloid leukemia (AML) development is well-known, but its prognostic significance is still elusive. Indoleamine 2,3-dioxygenase 1 (IDO1), which is negatively regulated by the BIN1 proto-oncogene, is an interferon-γ-inducible mediator of immune tolerance. With the aim to develop a prognostic IDO1-based immune gene signature, biological and clinical data of 982 patients with newly diagnosed, nonpromyelocytic AML were retrieved from public datasets and analyzed using established computational pipelines. Targeted transcriptomic profiles of 24 diagnostic BM samples were analyzed using the NanoString’s nCounter platform. BIN1 and IDO1 were inversely correlated and individually predicted overall survival. PLXNC1, a semaphorin receptor involved in inflammation and immune response, was the IDO1-interacting gene retaining the strongest prognostic value. The incorporation of PLXNC1 into the 2-gene IDO1-BIN1 score gave rise to a powerful immune gene signature predicting survival, especially in patients receiving chemotherapy. The top differentially expressed genes between IDO1^lowand IDO-1^high and between PLXNC1^lowand PLXNC1^high cases further improved the prognostic value of IDO1 providing a 7- and 10-gene immune signature, highly predictive of survival and correlating with AML mutational status at diagnosis. Taken together, our data indicate that IDO1 is pivotal for the construction of an immune gene signature predictive of survival in AML patients. Given the emerging role of immunotherapies for AML, our findings support the incorporation of immune biomarkers into current AML classification and prognostication algorithms.

PLXNC1: A Novel Potential Immune-Related Target for Stomach Adenocarcinoma

Background

Gastric cancer is associated with tumor microenvironment and chronic inflammation, but the underlying tumor-promoting mechanisms still remain unknown.

Methods

The ATAC-seq was used to identify genes with chromatin accessibilities in promoter regions. The RNA-seq datasets were performed to identify differentially expressed genes (DEGs). Pearson correlation analysis with the mRNA expression of three families of tumor-related inflammation TFs was used to filter downstream DEGs. Cox univariate survival analysis was performed to identify the prognostic value. The ImmPort database and CIBERSORTx algorithm were used to investigate the regulatory relationship between hub DEGs and immune cells. Immunohistochemistry (IHC) and multidimensional database were performed to verification.

Results

In this case, we require 2,454 genes with chromatin accessibility in promoter regions by ATAC-seq. Based on the gene expression profiles (RNA-seq), we identified 365 genes with chromatin accessibility and differential expression. Combined with the Cox univariate survival analysis, we identified 32 survival-related DEGs with chromatin accessibility. According to ImmPort database, CXCL3, PLXNC1, and EDN2 were identified as immune- related genes in STAD. By applying the CIBERSORTx algorithm and Pearson correlation, PLXNC1 was the only gene correlated with various immune cells, significantly associated with M2 macrophages. Furthermore, gene set variation analysis (GSVA) suggests the "hallmark_interferon_gamma_response" pathway was most significantly correlated with PLXNC1. Immunohistochemistry results revealed that PLXNC1 protein level was significantly higher in STAD tissues than in normal tissues (p < 0.001).

Conclusion

PLXNC1, regulated by IRF5, is an immune-related gene that was significantly associated with M2 macrophages and poor outcome in stomach adenocarcinoma.

The Expression of Semaphorin 7A in Human Periapical Lesions

INTRODUCTION

Semaphorin 7A (SEMA7A) is a membrane-bound or secretory protein exerting multiple functions in the regulation of inflammation, neural degradation, and cancer progression. Human periapical lesions are chronic and infectious diseases mainly caused by bacteria. However, the involvement of SEMA7A in human periapical lesions is still unclear. This study aimed to explore the expression of SEMA7A in human periapical lesions accompanied by the potential association of SEMA7A with matrix metalloproteinase (MMP)-1 and MMP-3 during the progression of apical periodontitis.

METHODS

Samples of periapical lesions and healthy controls were collected. Total RNA and protein were extracted respectively for quantitative real-time polymerase chain reaction and Western blot analysis. Additionally, 6 healthy samples and 27 periapical lesion samples were fixed, dehydrated, and embedded for further histologic and immunochemical analysis. The expression of SEMA7A was quantified by average integrated optical density. Immunofluorescence analysis was conducted to explore the colocalization of SEMA7A/MMP-1 and SEMA7A/MMP-3.

RESULTS

Compared with healthy controls, the messenger RNA and protein expression of SEMA7A was markedly up-regulated in periapical lesions. A stronger expression of MMP-1, MMP-3, and inflammatory cytokines was exhibited in periapical lesions than in healthy groups. An increasing expression of SEMA7A can be observed in both the periapical granuloma group and the radicular cyst group compared with the normal group (P < .01). Immunofluorescence results showed the colocalization of SEMA7A with both MMP-1 and MMP-3 in vascular vessels and extracellular matrix.

CONCLUSIONS

SEMA7A was up-regulated in periapical periodontitis and might be involved in the tissue destruction and infiltration of immune cells in periapical lesions.

The Role of Semaphorins and Their Receptors in Innate Immune Responses and Clinical Diseases of Acute Inflammation

Semaphorins are a group of proteins that have been studied extensively for their critical function in neuronal development. They have been shown to regulate airway development, tumorigenesis, autoimmune diseases, and the adaptive immune response. Notably, emerging literature describes the role of immunoregulatory semaphorins and their receptors, plexins and neuropilins, as modulators of innate immunity and diseases defined by acute injury to the kidneys, abdomen, heart and lungs. In this review we discuss the pathogenic functions of semaphorins in clinical conditions of acute inflammation, including sepsis and acute lung injury, with a focus on regulation of the innate immune response as well as potential future therapeutic targeting.

The role of immune semaphorins in the pathogenesis of multiple sclerosis: Potential therapeutic targets

The immune and nervous systems possess a highly intricate network of synaptic connections, shared messenger molecules, and exquisite communication ways, allowing intercellular signal transduction. The semaphorins (Semas) were initially identified as axonal guidance molecules in the development of the nervous system but later were found to be implicated also in regulating the immune system, known in this case as the "immune Semas" or "immunoregulatory Semas". Increasingly, these molecules are involved in multiple aspects of both physiological and pathological immune responses and were recently indicated to take part in various immunological disorders, encompassing allergy, cancer, and autoimmunity. Semas transduce signals by connecting to their cognate receptors, namely, plexins and neuropilins. Some of them, like Sema-3F, have been found to function as the inducer of the remyelination process whereas some others, like Sema-3A and Sema-4D, act to inhibit this process, either directly or indirectly. Besides, Sema-4A is crucial to the differentiation of T helper type 1 (Th1) and Th17 cells that are potentially involved in the pathogenesis of multiple sclerosis (MS), an autoimmune disease of the central nervous system. This review aims to reveal the role of immune Semas in the pathogenesis of MS and its animal model, experimental autoimmune encephalomyelitis, focusing on the therapeutic usages of these molecules to treat this neurodegenerative disease.

The involvement of semaphorin 7A in tumorigenic and immunoinflammatory regulation

Semaphorins, a large group of highly conserved proteins, consist of eight subfamilies that are widely expressed in vertebrates, invertebrates, and viruses and exist in membrane-bound or secreted forms. First described as axon guidance cues during neurogenesis, semaphorins also perform physiological functions in other organ systems, such as bone homeostasis, immune response, and tumor progression. Semaphorin 7A (SEMA7A), also known as CDw108, is an immune semaphorin that modulates diverse immunoinflammatory processes, including immune cell interactions, inflammatory infiltration, and cytokine production. In addition, SEMA7A regulates the proliferation, migration, invasion, lymph formation, and angiogenesis of multiple types of tumor cells, and these effects are mediated by the interaction of SEMA7A with two specific receptors, PLXNC1 and integrins. Thus, SEMA7A is intimately related to the pathogenesis of multiple autoimmune and inflammation-related diseases and tumors. This review focuses on the role of SEMA7A in the pathogenesis of autoimmune disorders, inflammatory diseases, and tumors, as well as the underlying mechanisms. Furthermore, strategies targeting SEMA7A as a potential predictive, diagnostic, and therapeutic agent for these diseases are also addressed.

Early transcriptional changes after UVB treatment in atopic dermatitis include inverse regulation of IL-36γ and IL-37

Phototherapy with narrow-band Ultraviolet B (nb-UVB) is a major therapeutic option in atopic dermatitis (AD), yet knowledge of the early molecular responses to this treatment is lacking. The objective of this study was to map the early transcriptional changes in AD skin in response to nb-UVB treatment. Adult patients (n = 16) with AD were included in the study and scored with validated scoring tools. AD skin was irradiated with local nb-UVB on day 0, 2 and 4. Skin biopsies were taken before and after treatment (day 0 and 7) and analysed for genome-wide modulation of transcription. When examining the early response after three local UVB treatments, gene expression analysis revealed 77 significantly modulated transcripts (30 down- and 47 upregulated). Among them were transcripts related to the inflammatory response, melanin synthesis, keratinization and epidermal structure. Interestingly, the pro-inflammatory cytokine IL-36γ was reduced after treatment, while the anti-inflammatory cytokine IL-37 increased after treatment with nb-UVB. There was also a modulation of several other mediators involved in inflammation, among them defensins and S100 proteins. This is the first study of early transcriptomic changes in AD skin in response to nb-UVB. We reveal robust modulation of a small group of inflammatory and anti-inflammatory targets, including the IL-1 family members IL36γ and IL-37, which is evident before any detectable changes in skin morphology or immune cell infiltrates. These findings provide important clues to the molecular mechanisms behind the treatment response and shed light on new potential treatment targets.

Combining Gene-Disease Associations with Single-Cell Gene Expression Data Provides Anatomy-Specific Subnetworks in Age-Related Macular Degeneration

Background: Age-related macular degeneration (AMD) is the most common cause of visual impairment in the developed world. Despite some treatment options for late AMD, there is no intervention that blocks early AMD proceeding to the late and blinding forms. This is partly due to the lack of precise drug targets, despite great advances in genetics, epidemiology, and protein-protein interaction (PPI) networks proposed to be driving the disease pathology. A systems approach to narrow down PPI networks to specific protein drug targets would provide new therapeutic options. Materials and Methods: In this study we analyzed single cell RNAseq (RNA sequencing) datasets of 17 cell types present in choroidal, retinal pigment epithelium (RPE), and neural retina (NR) tissues to explore if a more granular analysis incorporating different cell types exposes more specific pathways and relationships. Furthermore, we developed a novel and systematic gene ontology database (SysGO) to explore if a subcellular classification of processes will further enhance the understanding of the pathogenesis of this complex disorder and its comorbidities with other age-related diseases. Results: We found that 57% of the AMD (risk) genes are among the top 25% expressed genes in ∼1 of the 17 choroidal/RPE/NR cell types, and 9% were among the top 1% of expressed genes. Using SysGO, we identified an enrichment of AMD genes in cell membrane and extracellular anatomical locations, and we found both functional enrichments (e.g., cell adhesion) and cell types (e.g., fibroblasts, microglia) not previously associated with AMD pathogenesis. We reconstructed PPI networks among the top expressed AMD genes for all 17 choroidal/RPE/NR cell types, which provides molecular and anatomical definitions of AMD phenotypes that can guide therapeutic approaches to target this complex disease. Conclusion: We provide mechanism-based AMD endophenotypes that can be exploited in vitro, using computational models and for drug discovery/repurposing.

Gene expression of semaphorin-3A, semaphorin-7A, neuropilin-1, plexin-C1, and β1 integrin in treated-multiple sclerosis patients

OBJECTIVE

Recently, members of the semaphorin family have received major attention in various medical fields, especially autoimmunity. In this study, we selected semaphorin-3A (Sema3A), semaphorin-7A (Sema7A), and their receptors to determine the possible relationship between these molecules and multiple sclerosis (MS).

METHOD

We measured the gene expression of Sema3A, Sema7A, neuropilin-1 (NP-1), plexin-C1, and β1 integrin in the blood samples of relapsing-remitting multiple sclerosis (RRMS) patients, treated with high-dose interferon-β1a (IFN-β1a), low-dose IFN-β1a, IFN-β1b, and glatiramer acetate (GA) via quantitative real-time polymerase chain reaction (qRT-PCR) assay, and then, compared the results of treatment-naive patients with the healthy controls.

RESULTS

The gene expression of Sema3A (P = 0.02), NP-1 (P < 0.001), and plexin-C1 (P < 0.01) significantly decreased in the treatment-naive group, compared to the healthy controls. Sema3A significantly increased in all treated patients, compared to the treatment-naive patients (P < 0.001). However, expression of NP-1 (P < 0.001), plexin-C1 (P < 0.001), and β1 integrin (P < 0.05) only increased in patients receiving high-dose IFN-β1a, IFN-β1b, and GA. Expression of Sema7A increased in only two groups of patients treated with IFN-β1b (P < 0.001) and GA (P = 0.018), without any significant decrease in the treatment-naive group, compared to the healthy controls (P > 0.05).

CONCLUSION

Our findings confirm that the presence of Sema3A, Sema7A, and their receptors can play critical roles in the treatment of MS patients. Therefore, they can be potential target molecules for MS treatment in the future.

PLXNC1 Enhances Carcinogenesis Through Transcriptional Activation of IL6ST in Gastric Cancer

Background: Transcriptional factors (TFs) are responsible for orchestrating gene transcription during cancer progression. However, their roles in gastric cancer (GC) remain unclear.

Methods: We analyzed the differential expressions of TFs and, using GC cells and tissues, investigated plexin C1 (PLXNC1) RNA levels, as well as PLXNC1's clinical relevance and functional mechanisms. The molecular function of PLXNC1 was evaluated in vitro and in vivo. Kaplan-Meier curves and the log-rank test were used to analyze overall survival (OS) and disease-free survival (DFS).

Results: PLXNC1 was frequently up-regulated in GC and associated with poor prognosis. The expression level of PLXNC1 could serve as an independent biomarker to predict a patient's overall survival. Notably, knockdown of PLXNC1 significantly abolished GC cell proliferation, and migration, and overexpression of PLXNC1 accelerated carcinogenesis in GC. The gene set enrichment analysis (GSEA) indicated that high-expression of PLXNC1 was positively correlated with the activation of epithelial-mesenchymal transition (EMT), TNF-α, and IL-6/STAT3 signaling pathways. PLXNC1 promoted proliferation and migration of GC cells through transcriptional activation of the interleukin 6 signal transducer (IL6ST), which could rescue the malignant behavior of PLXNC1-deficient GC cells.

Conclusions: Our study demonstrated that the PLXNC1 plays an oncogenic role in GC patients. The PLXNC1-IL6ST axis represents a novel potential therapeutic target for GC.

Neutrophil Recruitment: From Model Systems to Tissue-Specific Patterns

Neutrophil recruitment is not only vital for host defense, but also relevant in pathological inflammatory reactions, such as sepsis. Model systems have been established to examine different steps of the leukocyte recruitment cascade in vivo and in vitro under inflammatory conditions. Recently, tissue-specific recruitment patterns have come into focus, requiring modification of formerly generalized assumptions. Here, we summarize existing models of neutrophil recruitment and highlight recent discoveries in organ-specific recruitment patterns. New techniques show that previously stated assumptions of integrin activation and tissue invasion may need revision. Similarly, neutrophil recruitment to specific organs can rely on different organ properties, adhesion molecules, and chemokines. To advance our understanding of neutrophil recruitment, organ-specific intravital microscopy methods are needed.

Comprehensive analysis of an lncRNA-miRNA-mRNA competing endogenous RNA network in pulpitis

Background

Pulpitis is a common inflammatory disease that affects dental pulp. It is important to understand the molecular signals of inflammation and repair associated with this process. Increasing evidence has revealed that long noncoding RNAs (lncRNAs), via competitively sponging microRNAs (miRNAs), can act as competing endogenous RNAs (ceRNAs) to regulate inflammation and reparative responses. The aim of this study was to elucidate the potential roles of lncRNA, miRNA and messenger RNA (mRNA) ceRNA networks in pulpitis tissues compared to normal control tissues.

Methods

The oligo and limma packages were used to identify differentially expressed lncRNAs and mRNAs (DElncRNAs and DEmRNAs, respectively) based on expression profiles in two datasets, GSE92681 and GSE77459, from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were further analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Protein–protein interaction (PPI) networks and modules were established to screen hub genes using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and the Molecular Complex Detection (MCODE) plugin for Cytoscape, respectively. Furthermore, an lncRNA-miRNA-mRNA-hub genes regulatory network was constructed to investigate mechanisms related to the progression and prognosis of pulpitis. Then, quantitative real-time polymerase chain reaction (qRT-PCR) was applied to verify critical lncRNAs that may significantly affect the pathogenesis in inflamed and normal human dental pulp.

Results

A total of 644 upregulated and 264 downregulated differentially expressed genes (DEGs) in pulpitis samples were identified from the GSE77459 dataset, while 8 up- and 19 downregulated probes associated with lncRNA were identified from the GSE92681 dataset. Protein–protein interaction (PPI) based on STRING analysis revealed a network of DEGs containing 4,929 edges and 623 nodes. Upon combined analysis of the constructed PPI network and the MCODE results, 10 hub genes, including IL6, IL8, PTPRC, IL1B, TLR2, ITGAM, CCL2, PIK3CG, ICAM1, and PIK3CD, were detected in the network. Next, a ceRNA regulatory relationship consisting of one lncRNA (PVT1), one miRNA (hsa-miR-455-5p) and two mRNAs (SOCS3 and PLXNC1) was established. Then, we constructed the network in which the regulatory relationship between ceRNA and hub genes was summarized. Finally, our qRT-PCR results confirmed significantly higher levels of PVT1 transcript in inflamed pulp than in normal pulp tissues (p = 0.03).

Conclusion

Our study identified a novel lncRNA-mediated ceRNA regulatory mechanisms in the pathogenesis of pulpitis.

Semaphorin 7A modulates cytokine-induced memory-like responses by human natural killer cells

Cytokine-induced memory-like (CIML) NK cells are endowed with the capacity to mediate enhanced effector functions upon cytokine or activating receptor restimulation for several weeks following short-term preactivation with IL-12, IL-15, and IL-18. Promising results from a first-in-human clinical trial highlighted the clinical potential of CIML NK cells as adoptive immunotherapy for patients with hematologic malignancies. However, the mechanisms underlying CIML NK cell differentiation and increased functionality remain incompletely understood. Semaphorin 7A (SEMA7A) is a potent immunomodulator expressed in activated lymphocytes and myeloid cells. In this study, we show that SEMA7A is substantially upregulated on NK cells stimulated with cytokines, and specifically marks activated NK cells with a strong potential to release IFN-γ. In particular, preactivation of NK cells with IL-12+IL-15+IL-18 resulted in greater than tenfold upregulation of SEMA7A and enhanced expression of the ligand for SEMA7A, integrin-β1, on CIML NK cells. Strikingly, preactivation in the presence of antibodies targeting SEMA7A lead to significantly decreased IFN-γ production following restimulation. These results imply a novel mechanism by which cytokine-enhanced SEMA7A/integrin-β1 interaction promotes CIML NK cell differentiation and maintenance of increased functionality. Our data suggest that targeting SEMA7A/integrin-β1 signaling might provide a novel immunotherapeutic approach to potentiate antitumor activity of CIML NK cells.

Semaphorins and Their Roles in Airway Biology: Potential as Therapeutic Targets

Semaphorins are a large family of proteins originally identified as axon guidance cues that play a crucial role in neural development. They are also ubiquitously expressed beyond the nervous system and contribute to regulation of essential cell functions, such as cell migration, proliferation, and adhesion. Binding of semaphorins to their receptors, including plexins and neuropilins, triggers diverse signaling pathways, which are involved in the pathogenesis of various diseases, from cancer to autoimmune and allergic disorders. Despite emerging evidence suggestive of nonredundant roles of semaphorins in cellular and molecular mechanisms of the airway biology, their precise expression and function have not been fully addressed. Here, we first provide an overview about the semaphorin family, their receptors, signaling pathways, and their cellular functions. Then, we highlight the novel findings on the role of semaphorins in airway biology under developmental, homeostatic, and pathological conditions. In particular, we discuss the dual roles of semaphorins in respiratory disorders where they can up- or downregulate processes underlying the pathophysiology of the airway diseases. Next, our recent findings on the expression and function of semaphorin 3E in allergic asthma are further emphasized, and its potential mechanism of action in allergic airway inflammation and remodeling is discussed. Finally, we raise some unanswered questions aiming to develop future research directions.

A systems medicine approach reveals disordered immune system and lipid metabolism in multiple sclerosis patients

Identification of autoimmune processes and introduction of new autoantigens involved in the pathogenesis of multiple sclerosis (MS) can be helpful in the design of new drugs to prevent unresponsiveness and side effects in patients. To find significant changes, we evaluated the autoantibody repertoires in newly diagnosed relapsing-remitting MS patients (NDP) and those receiving disease-modifying therapy (RP). Through a random peptide phage library, a panel of NDP- and RP-specific peptides was identified, producing two protein data sets visualized using Gephi, based on protein--protein interactions in the STRING database. The top modules of NDP and RP networks were assessed using Enrichr. Based on the findings, a set of proteins, including ATP binding cassette subfamily C member 1 (ABCC1), neurogenic locus notch homologue protein 1 (NOTCH1), hepatocyte growth factor receptor (MET), RAF proto-oncogene serine/threonine-protein kinase (RAF1) and proto-oncogene vav (VAV1) was found in NDP and was involved in over-represented terms correlated with cell-mediated immunity and cancer. In contrast, transcription factor RelB (RELB), histone acetyltransferase p300 (EP300), acetyl-CoA carboxylase 2 (ACACB), adiponectin (ADIPOQ) and phosphoenolpyruvate carboxykinase 2 mitochondrial (PCK2) had major contributions to viral infections and lipid metabolism as significant events in RP. According to these findings, further research is required to demonstrate the pathogenic roles of such proteins and autoantibodies targeting them in MS and to develop therapeutic agents which can ameliorate disease severity.

Protein Translation and Signaling in Human Eosinophils

We have recently reported that, unlike IL-5 and GM-CSF, IL-3 induces increased translation of a subset of mRNAs. In addition, we have demonstrated that Pin1 controls the activity of mRNA binding proteins, leading to enhanced mRNA stability, GM-CSF protein production and prolonged eosinophil (EOS) survival. In this review, discussion will include an overview of cap-dependent protein translation and its regulation by intracellular signaling pathways. We will address the more general process of mRNA post-transcriptional regulation, especially regarding mRNA binding proteins, which are critical effectors of protein translation. Furthermore, we will focus on (1) the roles of IL-3-driven sustained signaling on enhanced protein translation in EOS, (2) the mechanisms regulating mRNA binding proteins activity in EOS, and (3) the potential targeting of IL-3 signaling and the signaling leading to mRNA binding activity changes to identify therapeutic targets to treat EOS-associated diseases.

Endothelial semaphorin 7A promotes seawater aspiration-induced acute lung injury through plexin C1 and β1 integrin

Inflammation and edema are two main characteristics in seawater aspiration‑induced acute lung injury (ALI). In a previous study of the authors, it was demonstrated that endothelial semaphorin 7A (SEMA7A) serves an important role in the development of seawater‑induced inflammation and edema. However, the mechanism of endothelial SEMA7A‑mediated ALI remains unclear. Therefore, the authors explored the effect of SEMA7A in rat pulmonary microvascular endothelial cells (RPMVECs) and the interaction between endothelial SEMA7A and alveolar macrophages during seawater aspiration‑induced ALI. The role of SEMA7A in endothelial permeability was detected using plexin C1 blocking antibody or SEMA7A small interfering (si)RNA. In addition, RPMVECs were co‑cultured with rat alveolar macrophage cell line‑NR8383 cells and pro‑inflammatory cytokine production was detected. Interaction between the β1 integrin and SEMA7A was detected using the β1 integrin blocking antibody or SEMA7A siRNA. Seawater stimulation induced endothelial cytoskeleton remodeling, endothelial permeability, phosphorylation of cofilin, and increased the vascular endothelial growth factor (VEGF) expression in RPMVECs. Moreover, seawater stimulation led to expression of proinflammatory cytokines and activated the nuclear factor‑κB pathway in co‑cultured cells. However, blockage with the plexin C1 antibody inhibited endothelial cytoskeleton remodeling, endothelial permeability, phosphorylation of cofilin, and treatment with SEMA7A siRNA inhibited expression of VEGF in RPMVECs. In addition, blockage with β1 integrin antibody reduced expression of proinflammatory cytokines and inhibited activation of NF‑κB in co‑culture cells. These results suggest that SEMA7A promotes seawater induced lung edema via plexin C1 and stimulates seawater induced lung inflammation via β1 integrin.

Immunomodulatory Functions of Neuronal Guidance Proteins

Neuronal guidance proteins (NGPs) were originally identified for their role during the embryonic development of the nervous system. Recent years have seen the discovery of NGP functions during immune responses. In this context, NGPs were demonstrated to control leukocyte migration and the release of cytokines during conditions of acute inflammation, such as lung injury or sepsis. However, NGPs also display potent actions in the resolution of inflammation, chronic inflammatory conditions, the development of atherosclerosis, and during ischemia followed by reperfusion. Here, we provide an overview of the current state of knowledge about the role of NGPs in the immune system and describe their immunomodulatory function.

Stage-specific functions of Semaphorin7A during adult hippocampal neurogenesis rely on distinct receptors

The guidance protein Semaphorin7A (Sema7A) is required for the proper development of the immune and nervous systems. Despite strong expression in the mature brain, the role of Sema7A in the adult remains poorly defined. Here we show that Sema7A utilizes different cell surface receptors to control the proliferation and differentiation of neural progenitors in the adult hippocampal dentate gyrus (DG), one of the select regions of the mature brain where neurogenesis occurs. PlexinC1 is selectively expressed in early neural progenitors in the adult mouse DG and mediates the inhibitory effects of Sema7A on progenitor proliferation. Subsequently, during differentiation of adult-born DG granule cells, Sema7A promotes dendrite growth, complexity and spine development through β1-subunit-containing integrin receptors. Our data identify Sema7A as a key regulator of adult hippocampal neurogenesis, providing an example of how differential receptor usage spatiotemporally controls and diversifies the effects of guidance cues in the adult brain.

The role of semaphorin 7A and its receptor plexin C1 in the migration of NSCLC cells

We aim to explore the role of semaphorin 7A (SEMA7A) and its receptor plexin C1 in the migration of NSCLC cells.

Current drug design to target the Semaphorin/Neuropilin/Plexin complexes

The Semaphorin/Neuropilin/Plexin (SNP) complexes control a wide range of biological processes. Consistently, activity deregulation of these complexes is associated with many diseases. The increasing knowledge on SNP had in turn validated these molecular complexes as novel therapeutic targets. Targeting SNP activities by small molecules, antibodies and peptides or by soluble semaphorins have been proposed as new therapeutic approach. This review is focusing on the latest demonstration of this potential and discusses some of the key questions that need to be addressed before translating SNP targeting into clinically relevant approaches.

A novel podocyte gene, semaphorin 3G, protects glomerular podocyte from lipopolysaccharide-induced inflammation

Kidney diseases including diabetic nephropathy have become huge medical problems, although its precise mechanisms are still far from understood. In order to increase our knowledge about the patho-physiology of kidney, we have previously identified >300 kidney glomerulus-enriched transcripts through large-scale sequencing and microarray profiling of the mouse glomerular transcriptome. One of the glomerulus-specific transcripts identified was semaphorin 3G (Sema3G) which belongs to the semaphorin family. The aim of this study was to analyze both the in vivo and in vitro functions of Sema3G in the kidney. Sema3G was expressed in glomerular podocytes. Although Sema3G knockout mice did not show obvious glomerular defects, ultrastructural analyses revealed partially aberrant podocyte foot processes structures. When these mice were injected with lipopolysaccharide to induce acute inflammation or streptozotocin to induce diabetes, the lack of Sema3G resulted in increased albuminuria. The lack of Sema3G in podocytes also enhanced the expression of inflammatory cytokines including chemokine ligand 2 and interleukin 6. On the other hand, the presence of Sema3G attenuated their expression through the inhibition of lipopolysaccharide-induced Toll like receptor 4 signaling. Taken together, our results surmise that the Sema3G protein is secreted by podocytes and protects podocytes from inflammatory kidney diseases and diabetic nephropathy.

Semaphorin 7A Aggravates Pulmonary Inflammation during Lung Injury

The extent of pulmonary inflammation during lung injury ultimately determines patient outcome. Pulmonary inflammation is initiated by the migration of neutrophils into the alveolar space. Recent work has demonstrated that the guidance protein semaphorin 7A (SEMA7A) influences the migration of neutrophils into hypoxic tissue sites, yet, its role during lung injury is not well understood. Here, we report that the expression of SEMA7A is induced in vitro through pro-inflammatory cytokines. SEMA7A itself induces the production of pro-inflammatory cytokines in endothelial and epithelial cells, enhancing pulmonary inflammation. The induction of SEMA7A facilitates the transendothelial migration of neutrophils. In vivo, animals with deletion of SEMA7A expression showed reduced signs of pulmonary inflammatory changes following lipopolysaccharide challenge. We define here the role of SEMA7A in the development of lung injury and identify a potential pathway to interfere with these detrimental changes. Future anti-inflammatory strategies for the treatment of lung injury might be based on this finding.

Dynamic weight bearing as a non-reflexive method for the measurement of abdominal pain in mice

BACKGROUND

Chronic pelvic pain (CPP) is a high burden for patients and society. It affects 15-24% of women in reproductive age and is an area of high unmet medical need. CPP can be caused by a wide range of visceral diseases such as abdominal infections, gastrointestinal or gynaecological diseases like endometriosis. Despite the high medical need for this condition, pharmacological approaches are hampered by the limited number of available methods for the behavioural evaluation of pain in inflammation-driven animal models of pelvic pain.

METHODS

The dynamic weight bearing (DWB) system was used for the evaluation of spontaneous behaviour changes in the zymosan-induced peritonitis mouse model. Inflammatory mediator levels were evaluated in peritoneal lavage and their correlation with the behavioural endpoints was assessed. We evaluated the effect on behavioural endpoints of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib and the Nav 1.8 blocker A-803467.

RESULTS

The presence of a relief posture, characterized by a significantly increased weight distribution towards the front paws, was observed following intraperitoneal injection of zymosan. A positive correlation was detected between PGE2 levels in the peritoneal lavage and DWB endpoints. In addition, zymosan-induced weight bearing changes were reverted by celecoxib and A-803467.

CONCLUSIONS

This study described for the first time the use of DWB as a non-subjective and non-reflexive method for the evaluation of inflammatory-driven abdominal pain in a mouse model.

Differential expression of sema3A and sema7A in a murine model of multiple sclerosis: Implications for a therapeutic design

We characterised the expression of semaphorin (sema)3A, sema7A and their receptors in the immune and the central nervous system (CNS) at different stages of experimental autoimmune encephalomyelitis (EAE). We also studied their expression in neonatal and adult oligodendrocyte progenitor cell (OPC) and in mature oligodendrocyte cultures. Our results show that sema3A is increased in the CNS and decreased in the immune system upon EAE induction. However, sema7A expression is increased in both the CNS and the immune system during EAE. We also detected sema3A, sema7A and their receptors in neonatal and adult OPCs and in mature oligodendrocytes. These data suggest that sema3A and sema7A are involved in the pathogenesis of EAE, in the modulation of the immune response and in the neurodegeneration that take place in the CNS. Sema7A may represent an intriguing potential therapeutic target for the treatment of both the neurodegenerative and immune-mediated disease processes in MS.

Semaphorin 7A plays a critical role in IgE-mediated airway inflammation in mice

Elevated allergen-specific IgE levels are a hallmark of allergic asthma, a disease involving chronic airway inflammation characterized by airway hyperresponsiveness (AHR); neutrophilic airway inflammation is found in patients with severe asthma. Furthermore, we have reported that interleukin (IL)-33 and IL-17A contribute to IgE-mediated AHR through neutrophilic inflammation in mice. Meanwhile, semaphorins regulating neuronal and immune function have been focused on in several diseases. Here, we investigated whether semaphorin 7A (SEMA7A) is related to IgE-mediated neutrophilic inflammation in mice. BALB/c mice sensitized with antigen-specific IgE monoclonal antibody were repeatedly challenged by the antigen. When anti-SEMA7A antibody was administered during the fourth to seventh challenges, the infiltration by macrophages, lymphocytes, neutrophils, and eosinophils in the lungs was reduced at the seventh challenge (P<0.05, 0.05, 0.01, and 0.05, respectively). However, the increased production of IL-4, IL-5, IL-13, IL-33, IL-17A, IL-6, and CXCL1 in the lungs was not suppressed. In histological analysis, the epithelial cells, blood vessels, and inflammatory cells in the lungs of IgE-sensitized mice showed SEMA7A expression; plexin C1 for the receptor was expressed in the inflammatory cells. Meanwhile, we examined the effect of anti-SEMA7A antibody on AHR and neutrophilic inflammation enhanced by the collaborative action of IL-33 and IL-17A in normal mice, resulting in the suppression of these responses (P<0.05 and 0.01, respectively). Collectively, we demonstrated that SEMA7A plays a critical role in IgE-mediated neutrophilic airway inflammation. Therefore, SEMA7A may be a potential therapeutic target for severe allergic asthma showing neutrophilic airway inflammation.