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1.
Proc Natl Acad Sci U S A ; 121(22): e2400648121, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38781210

ABSTRACT

After central nervous system injury, a rapid cellular and molecular response is induced. This response can be both beneficial and detrimental to neuronal survival in the first few days and increases the risk for neurodegeneration if persistent. Semaphorin4B (Sema4B), a transmembrane protein primarily expressed by cortical astrocytes, has been shown to play a role in neuronal cell death following injury. Our study shows that after cortical stab wound injury, cytokine expression is attenuated in Sema4B-/- mice, and microglia/macrophage reactivity is altered. In vitro, Sema4B enhances the reactivity of microglia following injury, suggesting astrocytic Sema4B functions as a ligand. Moreover, injury-induced microglia reactivity is attenuated in the presence of Sema4B-/- astrocytes compared to Sema4B+/- astrocytes. In vitro experiments indicate that Plexin-B2 is the Sema4B receptor on microglia. Consistent with this, in microglia/macrophage-specific Plexin-B2-/- mice, similar to Sema4B-/- mice, microglial/macrophage reactivity and neuronal cell death are attenuated after cortical injury. Finally, in Sema4B/Plexin-B2 double heterozygous mice, microglial/macrophage reactivity is also reduced after injury, supporting the idea that both Sema4B and Plexin-B2 are part of the same signaling pathway. Taken together, we propose a model in which following injury, astrocytic Sema4B enhances the response of microglia/macrophages via Plexin-B2, leading to increased reactivity.


Subject(s)
Astrocytes , Mice, Knockout , Microglia , Nerve Tissue Proteins , Semaphorins , Animals , Microglia/metabolism , Microglia/pathology , Semaphorins/metabolism , Semaphorins/genetics , Astrocytes/metabolism , Mice , Nerve Tissue Proteins/metabolism , Nerve Tissue Proteins/genetics , Cell Communication , Brain Injuries/metabolism , Brain Injuries/pathology , Brain Injuries/genetics , Mice, Inbred C57BL , Macrophages/metabolism
2.
Cell Rep Med ; 5(5): 101554, 2024 May 21.
Article in English | MEDLINE | ID: mdl-38729157

ABSTRACT

The axons of retinal ganglion cells (RGCs) form the optic nerve, transmitting visual information from the eye to the brain. Damage or loss of RGCs and their axons is the leading cause of visual functional defects in traumatic injury and degenerative diseases such as glaucoma. However, there are no effective clinical treatments for nerve damage in these neurodegenerative diseases. Here, we report that LIM homeodomain transcription factor Lhx2 promotes RGC survival and axon regeneration in multiple animal models mimicking glaucoma disease. Furthermore, following N-methyl-D-aspartate (NMDA)-induced excitotoxicity damage of RGCs, Lhx2 mitigates the loss of visual signal transduction. Mechanistic analysis revealed that overexpression of Lhx2 supports axon regeneration by systematically regulating the transcription of regeneration-related genes and inhibiting transcription of Semaphorin 3C (Sema3C). Collectively, our studies identify a critical role of Lhx2 in promoting RGC survival and axon regeneration, providing a promising neural repair strategy for glaucomatous neurodegeneration.


Subject(s)
Axons , Disease Models, Animal , Glaucoma , LIM-Homeodomain Proteins , Nerve Regeneration , Retinal Ganglion Cells , Transcription Factors , Animals , Retinal Ganglion Cells/metabolism , Retinal Ganglion Cells/pathology , LIM-Homeodomain Proteins/metabolism , LIM-Homeodomain Proteins/genetics , Glaucoma/genetics , Glaucoma/pathology , Glaucoma/metabolism , Transcription Factors/metabolism , Transcription Factors/genetics , Axons/metabolism , Axons/pathology , Mice , Nerve Regeneration/genetics , Nerve Regeneration/physiology , Mice, Inbred C57BL , Cell Survival/genetics , Semaphorins/metabolism , Semaphorins/genetics , N-Methylaspartate/metabolism
3.
Development ; 151(10)2024 May 15.
Article in English | MEDLINE | ID: mdl-38738602

ABSTRACT

Visual circuit development is characterized by subdivision of neuropils into layers that house distinct sets of synaptic connections. We find that, in the Drosophila medulla, this layered organization depends on the axon guidance regulator Plexin A. In Plexin A null mutants, synaptic layers of the medulla neuropil and arborizations of individual neurons are wider and less distinct than in controls. Analysis of semaphorin function indicates that Semaphorin 1a, acting in a subset of medulla neurons, is the primary partner for Plexin A in medulla lamination. Removal of the cytoplasmic domain of endogenous Plexin A has little effect on the formation of medulla layers; however, both null and cytoplasmic domain deletion mutations of Plexin A result in an altered overall shape of the medulla neuropil. These data suggest that Plexin A acts as a receptor to mediate morphogenesis of the medulla neuropil, and as a ligand for Semaphorin 1a to subdivide it into layers. Its two independent functions illustrate how a few guidance molecules can organize complex brain structures by each playing multiple roles.


Subject(s)
Drosophila Proteins , Morphogenesis , Nerve Tissue Proteins , Neuropil , Optic Lobe, Nonmammalian , Receptors, Cell Surface , Semaphorins , Animals , Drosophila Proteins/metabolism , Drosophila Proteins/genetics , Semaphorins/metabolism , Semaphorins/genetics , Nerve Tissue Proteins/metabolism , Nerve Tissue Proteins/genetics , Morphogenesis/genetics , Neuropil/metabolism , Optic Lobe, Nonmammalian/metabolism , Optic Lobe, Nonmammalian/embryology , Receptors, Cell Surface/metabolism , Receptors, Cell Surface/genetics , Drosophila melanogaster/metabolism , Drosophila melanogaster/genetics , Drosophila melanogaster/embryology , Neurons/metabolism , Drosophila/metabolism , Drosophila/embryology , Mutation/genetics
4.
Commun Biol ; 7(1): 541, 2024 May 07.
Article in English | MEDLINE | ID: mdl-38714838

ABSTRACT

Age-related diseases pose great challenges to health care systems worldwide. During aging, endothelial senescence increases the risk for cardiovascular disease. Recently, it was described that Phosphatase 1 Nuclear Targeting Subunit (PNUTS) has a central role in cardiomyocyte aging and homeostasis. Here, we determine the role of PNUTS in endothelial cell aging. We confirm that PNUTS is repressed in senescent endothelial cells (ECs). Moreover, PNUTS silencing elicits several of the hallmarks of endothelial aging: senescence, reduced angiogenesis and loss of barrier function. Findings are validate in vivo using endothelial-specific inducible PNUTS-deficient mice (Cdh5-CreERT2;PNUTSfl/fl), termed PNUTSEC-KO. Two weeks after PNUTS deletion, PNUTSEC-KO mice present severe multiorgan failure and vascular leakage. Transcriptomic analysis of PNUTS-silenced HUVECs and lungs of PNUTSEC-KO mice reveal that the PNUTS-PP1 axis tightly regulates the expression of semaphorin 3B (SEMA3B). Indeed, silencing of SEMA3B completely restores barrier function after PNUTS loss-of-function. These results reveal a pivotal role for PNUTS in endothelial homeostasis through a SEMA3B downstream pathway that provides a potential target against the effects of aging in ECs.


Subject(s)
Cellular Senescence , Human Umbilical Vein Endothelial Cells , Semaphorins , Animals , Humans , Mice , Aging/metabolism , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , Endothelial Cells/metabolism , Endothelium, Vascular/metabolism , Human Umbilical Vein Endothelial Cells/metabolism , Membrane Glycoproteins/metabolism , Membrane Glycoproteins/genetics , Mice, Inbred C57BL , Mice, Knockout , RNA-Binding Proteins/metabolism , RNA-Binding Proteins/genetics , Semaphorins/metabolism , Semaphorins/genetics
5.
Int Immunopharmacol ; 132: 112035, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38603857

ABSTRACT

Hallmark features of the tumor microenvironment include immune cells, stromal cells, blood vessels, and extracellular matrix (ECM), providing a conducive environment for the growth and survival of tumors. Recent advances in the understanding of cancer biology have highlighted the functional role of semaphorins (SEMAs). SEMAs are a large and diverse family of widely expressed secreted and membrane-binding proteins, which were initially implicated in axon guidance and neural development. However, it is now clear that they are widely expressed beyond the nervous system and participate in regulating immune responses and cancer progression. In fact, accumulating evidence disclosed that different SEMAs can either stimulate or restrict tumor progression, some of which act as important regulators of tumor angiogenesis. Conversely, limited information is known about the functional relevance of SEMA signals in TME. In this setting, we systematically elaborate the role SEMAs and their major receptors played in characterized components of TME. Furthermore, we provide a convergent view of current SEMAs pharmacological progress in clinical treatment and also put forward their potential application value and clinical prospects in the future.


Subject(s)
Neoplasms , Semaphorins , Tumor Microenvironment , Animals , Humans , Neoplasms/immunology , Neoplasms/drug therapy , Neoplasms/metabolism , Neoplasms/therapy , Neovascularization, Pathologic/immunology , Semaphorins/metabolism , Signal Transduction
6.
BMC Pediatr ; 24(1): 285, 2024 Apr 27.
Article in English | MEDLINE | ID: mdl-38678170

ABSTRACT

BACKGROUND: Kawasaki disease (KD) is a pediatric systemic vasculitis characterized by endothelial cell dysfunction. Semaphorin 7A (Sema7A) has been reported to regulate endothelial phenotypes associated with cardiovascular diseases, while its role in KD remains unknown. This study aims to investigate the effect of Sema7A on endothelial permeability and inflammatory response in KD conditions. METHODS: Blood samples were collected from 68 KD patients and 25 healthy children (HC). The levels of Sema7A and A Disintegrin and Metalloprotease 17 (ADAM17) in serum were measured by enzyme-linked immunosorbent assay (ELISA), and Sema7A expression in blood cells was analyzed by flow cytometry. Ex vivo monocytes were used for Sema7A shedding assays. In vitro human coronary artery endothelial cells (HCAECs) were cultured in KD sera and stimulated with Sema7A, and TNF-α, IL-1ß, IL-6, and IL-18 of HCAECs were measured by ELISA and qRT-PCR. HCAECs monolayer permeability was measured by FITC-dextran. RESULTS: The serum level of Sema7A was significantly higher in KD patients than in HC and correlated with disease severity. Monocytes were identified as one of the source of elevated serum Sema7A, which implicates a process of ADAM17-dependent shedding. Sera from KD patients induced upregulation of plexin C1 and integrin ß1 in HCAECs compared to sera from HC. Sema7A mediated the proinflammatory cytokine production of HCAECs in an integrin ß1-dependent manner, while both plexin C1 and integrin ß1 contributed to Sema7A-induced HCAEC hyperpermeability. CONCLUSIONS: Sema7A is involved in the progression of KD vasculitis by promoting endothelial permeability and inflammation through a plexin C1 and integrin ß1-dependent pathway. Sema7A may serve as a potential biomarker and therapeutic target in the prognosis and treatment of KD.


Subject(s)
Antigens, CD , Integrin beta1 , Mucocutaneous Lymph Node Syndrome , Receptors, Cell Surface , Semaphorins , Child , Child, Preschool , Female , Humans , Infant , Male , ADAM17 Protein/metabolism , Antigens, CD/metabolism , Capillary Permeability , Case-Control Studies , Cells, Cultured , Endothelial Cells/metabolism , Endothelium, Vascular/metabolism , GPI-Linked Proteins , Inflammation/metabolism , Integrin beta1/metabolism , Monocytes/metabolism , Mucocutaneous Lymph Node Syndrome/metabolism , Mucocutaneous Lymph Node Syndrome/blood , Nerve Tissue Proteins/metabolism , Receptors, Cell Surface/metabolism , Receptors, Cell Surface/blood , Semaphorins/metabolism , Semaphorins/blood
7.
Int J Oral Sci ; 16(1): 26, 2024 Mar 28.
Article in English | MEDLINE | ID: mdl-38548747

ABSTRACT

SEMA7A belongs to the Semaphorin family and is involved in the oncogenesis and tumor progression. Aberrant glycosylation has been intricately linked with immune escape and tumor growth. SEMA7A is a highly glycosylated protein with five glycosylated sites. The underlying mechanisms of SEMA7A glycosylation and its contribution to immunosuppression and tumorigenesis are unclear. Here, we identify overexpression and aberrant N-glycosylation of SEMA7A in head and neck squamous cell carcinoma, and elucidate fucosyltransferase FUT8 catalyzes aberrant core fucosylation in SEMA7A at N-linked oligosaccharides (Asn 105, 157, 258, 330, and 602) via a direct protein‒protein interaction. A glycosylated statue of SEMA7A is necessary for its intra-cellular trafficking from the cytoplasm to the cytomembrane. Cytokine EGF triggers SEMA7A N-glycosylation through increasing the binding affinity of SEMA7A toward FUT8, whereas TGF-ß1 promotes abnormal glycosylation of SEMA7A via induction of epithelial-mesenchymal transition. Aberrant N-glycosylation of SEMA7A leads to the differentiation of CD8+ T cells along a trajectory toward an exhausted state, thus shaping an immunosuppressive microenvironment and being resistant immunogenic cell death. Deglycosylation of SEMA7A significantly improves the clinical outcome of EGFR-targeted and anti-PD-L1-based immunotherapy. Finally, we also define RBM4, a splice regulator, as a downstream effector of glycosylated SEMA7A and a pivotal mediator of PD-L1 alternative splicing. These findings suggest that targeting FUT8-SEMA7A axis might be a promising strategy for improving antitumor responses in head and neck squamous cell carcinoma patients.


Subject(s)
Head and Neck Neoplasms , Semaphorins , Humans , Glycosylation , Squamous Cell Carcinoma of Head and Neck , CD8-Positive T-Lymphocytes/metabolism , Fucosyltransferases/metabolism , Tumor Microenvironment , RNA-Binding Proteins/metabolism , Antigens, CD/metabolism , Semaphorins/metabolism , GPI-Linked Proteins/metabolism
8.
Blood Adv ; 8(11): 2660-2674, 2024 Jun 11.
Article in English | MEDLINE | ID: mdl-38489236

ABSTRACT

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.


Subject(s)
Antigens, CD , Neutrophils , Pneumonia , Semaphorins , Sepsis , Semaphorins/metabolism , Sepsis/immunology , Sepsis/metabolism , Neutrophils/metabolism , Neutrophils/immunology , Humans , Animals , Mice , Antigens, CD/metabolism , Pneumonia/metabolism , Pneumonia/immunology , GPI-Linked Proteins/metabolism , Male , Disease Models, Animal , Mice, Knockout , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/metabolism , Female
9.
Sci Rep ; 14(1): 7082, 2024 03 25.
Article in English | MEDLINE | ID: mdl-38528115

ABSTRACT

FOXA1 is a pioneer transcription factor that is frequently mutated in prostate, breast, bladder, and salivary gland malignancies. Indeed, metastatic castration-resistant prostate cancer (mCRPC) commonly harbour FOXA1 mutations with a prevalence of 35%. However, despite the frequent recurrence of FOXA1 mutations in prostate cancer, the mechanisms by which FOXA1 variants drive its oncogenic effects are still unclear. Semaphorin 3C (SEMA3C) is a secreted autocrine growth factor that drives growth and treatment resistance of prostate and other cancers and is known to be regulated by both AR and FOXA1. In the present study, we characterize FOXA1 alterations with respect to its regulation of SEMA3C. Our findings reveal that FOXA1 alterations lead to elevated levels of SEMA3C both in prostate cancer specimens and in vitro. We further show that FOXA1 negatively regulates SEMA3C via intronic cis elements, and that mutations in FOXA1 forkhead domain attenuate its inhibitory function in reporter assays, presumably by disrupting DNA binding of FOXA1. Our findings underscore the key role of FOXA1 in prostate cancer progression and treatment resistance by regulating SEMA3C expression and suggest that SEMA3C may be a driver of growth and tumor vulnerability of mCRPC harboring FOXA1 alterations.


Subject(s)
Hepatocyte Nuclear Factor 3-alpha , Prostatic Neoplasms, Castration-Resistant , Semaphorins , Humans , Male , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Hepatocyte Nuclear Factor 3-alpha/genetics , Hepatocyte Nuclear Factor 3-alpha/metabolism , Mutation , Prostate/pathology , Prostatic Neoplasms, Castration-Resistant/genetics , Prostatic Neoplasms, Castration-Resistant/pathology , Transcription Factors/metabolism , Semaphorins/genetics , Semaphorins/metabolism
10.
Elife ; 132024 Mar 25.
Article in English | MEDLINE | ID: mdl-38526535

ABSTRACT

Axon guidance molecules are critical for neuronal pathfinding because they regulate directionality and growth pace during nervous system development. However, the molecular mechanisms coordinating proper axonal extension and turning are poorly understood. Here, metastasis suppressor 1 (Mtss1), a membrane protrusion protein, ensured axonal extension while sensitizing axons to the Semaphorin 3E (Sema3E)-Plexin-D1 repulsive cue. Sema3E-Plexin-D1 signaling enhanced Mtss1 expression in projecting striatonigral neurons. Mtss1 localized to the neurite axonal side and regulated neurite outgrowth in cultured neurons. Mtss1 also aided Plexin-D1 trafficking to the growth cone, where it signaled a repulsive cue to Sema3E. Mtss1 ablation reduced neurite extension and growth cone collapse in cultured neurons. Mtss1-knockout mice exhibited fewer striatonigral projections and irregular axonal routes, and these defects were recapitulated in Plxnd1- or Sema3e-knockout mice. These findings demonstrate that repulsive axon guidance activates an exquisite autoregulatory program coordinating both axonal extension and steering during neuronal pathfinding.


Subject(s)
Cell Adhesion Molecules , Membrane Glycoproteins , Nerve Tissue Proteins , Semaphorins , Animals , Mice , Intracellular Signaling Peptides and Proteins , Membrane Glycoproteins/metabolism , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice, Knockout , Semaphorins/genetics , Semaphorins/metabolism
11.
Nat Commun ; 15(1): 2723, 2024 Mar 28.
Article in English | MEDLINE | ID: mdl-38548715

ABSTRACT

Integration of extracellular signals by neurons is pivotal for brain development, plasticity, and repair. Axon guidance relies on receptor-ligand interactions crosstalking with extracellular matrix components. Semaphorin-5A (Sema5A) is a bifunctional guidance cue exerting attractive and inhibitory effects on neuronal growth through the interaction with heparan sulfate (HS) and chondroitin sulfate (CS) glycosaminoglycans (GAGs), respectively. Sema5A harbors seven thrombospondin type-1 repeats (TSR1-7) important for GAG binding, however the underlying molecular basis and functions in vivo remain enigmatic. Here we dissect the structural basis for Sema5A:GAG specificity and demonstrate the functional significance of this interaction in vivo. Using x-ray crystallography, we reveal a dimeric fold variation for TSR4 that accommodates GAG interactions. TSR4 co-crystal structures identify binding residues validated by site-directed mutagenesis. In vitro and cell-based assays uncover specific GAG epitopes necessary for TSR association. We demonstrate that HS-GAG binding is preferred over CS-GAG and mediates Sema5A oligomerization. In vivo, Sema5A:GAG interactions are necessary for Sema5A function and regulate Plexin-A2 dependent dentate progenitor cell migration. Our study rationalizes Sema5A associated developmental and neurological disorders and provides mechanistic insights into how multifaceted guidance functions of a single transmembrane cue are regulated by proteoglycans.


Subject(s)
Glycosaminoglycans , Semaphorins , Glycosaminoglycans/metabolism , Proteoglycans/metabolism , Heparitin Sulfate/metabolism , Cell Movement , Semaphorins/genetics , Semaphorins/metabolism
12.
Cytokine Growth Factor Rev ; 76: 22-29, 2024 04.
Article in English | MEDLINE | ID: mdl-38472041

ABSTRACT

The bone marrow is a haven for hematopoietic and non-hematopoietic cells, creating complex micro-anatomical regions called niches. These distinct niches all participate in an intricate orchestra of cellular interactions that regulates the hematopoietic stem cell and its progenies. In this review, we provide a detailed description of the three most well-known bone marrow niches and their participation in hematopoiesis. We use pre-clinical data, including different in vitro and in vivo studies to discuss how a group of proteins called Semaphorins could potentially modulate both hematopoietic and non-hematopoietic cells, establishing links between the niches, semaphorins, and hematopoietic regulation. Thus, here we provide a deep dive into the inner functioning of the bone marrow and discuss the overarching implications that semaphorins might have on blood formation.


Subject(s)
Bone Marrow , Semaphorins , Humans , Cell Differentiation/physiology , Semaphorins/metabolism , Stem Cell Niche/physiology , Hematopoietic Stem Cells , Hematopoiesis/physiology , Bone Marrow Cells
13.
Mol Cell Neurosci ; 128: 103920, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38331011

ABSTRACT

Synapse formation in the mammalian brain is a complex and dynamic process requiring coordinated function of dozens of molecular families such as cell adhesion molecules (CAMs) and ligand-receptor pairs (Ephs/Ephrins, Neuroligins/Neurexins, Semaphorins/Plexins). Due to the large number of molecular players and possible functional redundancies within gene families, it is challenging to determine the precise synaptogenic roles of individual molecules, which is key to understanding the consequences of mutations in these genes for brain function. Furthermore, few molecules are known to exclusively regulate either GABAergic or glutamatergic synapses, and cell and molecular mechanisms underlying GABAergic synapse formation in particular are not thoroughly understood. We previously demonstrated that Semaphorin-4D (Sema4D) regulates GABAergic synapse development in the mammalian hippocampus while having no effect on glutamatergic synapse development, and this effect occurs through binding to its high affinity receptor, Plexin-B1. In addition, we demonstrated that RNAi-mediated Plexin-B2 knock-down decreases GABAergic synapse density suggesting that both receptors function in this process. Here, we perform a structure-function study of the Plexin-B1 and Plexin-B2 receptors to identify the protein domains in each receptor which are required for its synaptogenic function. Further, we examine whether Plexin-B2 is required in the presynaptic neuron, the postsynaptic neuron, or both to regulate GABAergic synapse formation. Our data reveal that Plexin-B1 and Plexin-B2 function non-redundantly to regulate GABAergic synapse formation and suggest that the transmembrane domain may underlie functional distinctions. We also provide evidence that Plexin-B2 expression in presynaptic GABAergic interneurons, as well as postsynaptic pyramidal cells, regulates GABAergic synapse formation in hippocampus. These findings lay the groundwork for future investigations into the precise signaling pathways required for synapse formation downstream of Plexin-B receptor signaling.


Subject(s)
Cell Adhesion Molecules , Receptors, Cell Surface , Semaphorins , Animals , Receptors, Cell Surface/genetics , Nerve Tissue Proteins/metabolism , Neurons/metabolism , Synapses/metabolism , Semaphorins/genetics , Semaphorins/metabolism , Mammals
14.
Sci Signal ; 17(819): eadh7673, 2024 Jan 16.
Article in English | MEDLINE | ID: mdl-38227686

ABSTRACT

The precise development of neuronal morphologies is crucial to the establishment of synaptic circuits and, ultimately, proper brain function. Signaling by the axon guidance cue semaphorin 3A (Sema3A) and its receptor complex of neuropilin-1 and plexin-A4 has multifunctional outcomes in neuronal morphogenesis. Downstream activation of the RhoGEF FARP2 through interaction with the lysine-arginine-lysine motif of plexin-A4 and consequent activation of the small GTPase Rac1 promotes dendrite arborization, but this pathway is dispensable for axon repulsion. Here, we investigated the interplay of small GTPase signaling mechanisms underlying Sema3A-mediated dendritic elaboration in mouse layer V cortical neurons in vitro and in vivo. Sema3A promoted the binding of the small GTPase Rnd1 to the amino acid motif lysine-valine-serine (LVS) in the cytoplasmic domain of plexin-A4. Rnd1 inhibited the activity of the small GTPase RhoA and the kinase ROCK, thus supporting the activity of the GTPase Rac1, which permitted the growth and branching of dendrites. Overexpression of a dominant-negative RhoA, a constitutively active Rac1, or the pharmacological inhibition of ROCK activity rescued defects in dendritic elaboration in neurons expressing a plexin-A4 mutant lacking the LVS motif. Our findings provide insights into the previously unappreciated balancing act between Rho and Rac signaling downstream of specific motifs in plexin-A4 to mediate Sema3A-dependent dendritic elaboration in mammalian cortical neuron development.


Subject(s)
Cell Adhesion Molecules , Monomeric GTP-Binding Proteins , Nerve Tissue Proteins , Semaphorins , Mice , Animals , Monomeric GTP-Binding Proteins/metabolism , Semaphorin-3A/genetics , Semaphorin-3A/metabolism , Lysine/metabolism , Neurons/metabolism , Dendrites/metabolism , Semaphorins/metabolism , Mammals/metabolism , Guanine Nucleotide Exchange Factors/metabolism , Adaptor Proteins, Signal Transducing/metabolism
15.
Mol Carcinog ; 63(3): 371-383, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37975495

ABSTRACT

Long noncoding RNAs (lncRNAs) are crucial regulators of tumor-initiating cells (TICs) and hold particular importance in triple negative breast cancer (TNBC). Yet, the precise mechanisms by which TIC-associated lncRNAs influence TNBC remain unclear. Our research utilized The Cancer Genome Atlas Breast Cancer (BC) data set to identify prognostic lncRNAs. We then conducted extensive assays to explore their impact on the tumor-initiating phenotype of TNBC cells and the underlying mechanisms. Notably, we found that low expression of lncRNA SEMA3B-AS1 correlated with unfavorable survival in BC patients. SEMA3B-AS1 was also downregulated in TNBC and linked to advanced tumor stage. Functional experiments confirmed its role as a TIC-suppressing lncRNA, curtailing mammosphere formation, ALDH + TIC cell proportion, and impairing clonogenicity, migration, and invasion. Mechanistic insights unveiled SEMA3B-AS1's nuclear localization and interaction with MLL4 (mixed-lineage leukemia 4), triggering H3K4 methylation-associated transcript activation and thus elevating the expression of SEMA3B, a recognized tumor suppressor gene. Our findings emphasize SEMA3B-AS1's significance as a TNBC-suppressing lncRNA that modulates TIC behavior. This study advances our comprehension of lncRNA's role in TNBC progression, advocating for their potential as therapeutic targets in this aggressive BC subtype.


Subject(s)
MicroRNAs , RNA, Long Noncoding , Semaphorins , Triple Negative Breast Neoplasms , Humans , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , Triple Negative Breast Neoplasms/pathology , MicroRNAs/genetics , Histone-Lysine N-Methyltransferase/genetics , Gene Expression Regulation, Neoplastic , Cell Proliferation/genetics , Cell Line, Tumor , Membrane Glycoproteins/metabolism , Semaphorins/genetics , Semaphorins/metabolism , Semaphorins/therapeutic use
16.
Nat Commun ; 14(1): 8097, 2023 Dec 07.
Article in English | MEDLINE | ID: mdl-38062045

ABSTRACT

Innervation of the hypothalamic median eminence by Gonadotropin-Releasing Hormone (GnRH) neurons is vital to ensure puberty onset and successful reproduction. However, the molecular and cellular mechanisms underlying median eminence development and pubertal timing are incompletely understood. Here we show that Semaphorin-6A is strongly expressed by median eminence-resident oligodendrocytes positioned adjacent to GnRH neuron projections and fenestrated capillaries, and that Semaphorin-6A is required for GnRH neuron innervation and puberty onset. In vitro and in vivo experiments reveal an unexpected function for Semaphorin-6A, via its receptor Plexin-A2, in the control of median eminence vascular permeability to maintain neuroendocrine homeostasis. To support the significance of these findings in humans, we identify patients with delayed puberty carrying a novel pathogenic variant of SEMA6A. In all, our data reveal a role for Semaphorin-6A in regulating GnRH neuron patterning by tuning the median eminence vascular barrier and thereby controlling puberty onset.


Subject(s)
Gonadotropin-Releasing Hormone , Semaphorins , Humans , Gonadotropin-Releasing Hormone/metabolism , Median Eminence/metabolism , Capillary Permeability , Neurons/metabolism , Puberty , Semaphorins/genetics , Semaphorins/metabolism
17.
Front Immunol ; 14: 1251026, 2023.
Article in English | MEDLINE | ID: mdl-38094294

ABSTRACT

Introduction: The study explores the role of endothelial Semaphorin 7A (SEMA7A) in inflammatory processes. SEMA7A is known for enhancing inflammation during tissue hypoxia and exhibiting anti-inflammatory properties in the intestinal system during colitis. This research extends the understanding of SEMA7A's function by examining its role in inflammatory peritonitis and intestinal inflammation. Methods: The research involved inducing peritonitis in SEMA7A knockout (SEMA7A-/-) and wild-type (WT) animals through Zymosan A (ZyA) injection. The inflammatory response was assessed by measuring cell count and cytokine release. In parallel, the study investigated the expression of SEMA7A in intestinal epithelial cells under inflammatory stimuli and its impact on interleukin 10 (IL-10) production using an in vitro co-culture model of monocytes and epithelial cells. Additionally, the distribution of SEMA7A target receptors, particularly ITGAV/ITGB1 (CD51/CD29), was analyzed in WT animals. Results: The results revealed that SEMA7A-/- animals exhibited increased inflammatory peritonitis compared to the WT animals. Inflammatory conditions in intestinal epithelial cells led to the induction of SEMA7A. The co-culture experiments demonstrated that SEMA7A induced IL-10 production, which depended on integrin receptors and was independent of PLXNC1 expression. Furthermore, ITGAV/ITGB1 emerged as the predominant SEMA7A receptor in the intestinal area of WT animals. Discussion: These findings underscore the multifaceted role of SEMA7A in inflammatory processes. The differential responses in peritonitis and intestinal inflammation suggest that SEMA7A's function is significantly influenced by the expression and distribution of its target receptors within different organ systems. The study highlights the complex and context-dependent nature of SEMA7A in mediating inflammatory responses.


Subject(s)
Peritonitis , Semaphorins , Animals , Antigens, CD/metabolism , Integrins , Interleukin-10/genetics , Semaphorins/genetics , Semaphorins/metabolism , Peritonitis/chemically induced , Inflammation
18.
Int J Mol Sci ; 24(24)2023 Dec 07.
Article in English | MEDLINE | ID: mdl-38139064

ABSTRACT

Semaphorins belong to a group of membrane and secretory proteins that act as ligands for several receptor families and are involved in modulating cell signaling pathways. They bind multimeric receptor complexes on the cell membrane to exert their effects and initiate unique intracellular signal transduction cascades. These proteins can influence several processes that are very important for cell function, such as cell division and differentiation. Semaphorins are involved in cell migration, apoptosis, cell adhesion, aggregation, and numerous immune processes due to their immunoregulatory effects. Semaphorins are expressed in keratinocytes, which is why they have become a target for studies on the pathogenesis of skin diseases. Most studies to date on the role of semaphorins in the pathogenesis of skin diseases have been carried out in cellular or animal models, and there are few clinical studies evaluating the role of semaphorins in the pathogenesis and therapy of skin diseases. In this narrative review, we summarized the current state of knowledge on the role of semaphorins in the pathogenesis of skin diseases and their potential importance as targets for therapy. We also tried to present the key findings and weaknesses of previous research in this field. The novelty of this article lies in the comprehensive presentation of the role of semaphorins in the pathogenesis of skin diseases, including the results of studies on cell cultures and animal models, elucidating the mechanisms and signaling pathways through which semaphorins affect the development of skin diseases, as well as on the presentation of the results of existing clinical trials evaluating the role of semaphorins in the pathogenesis of skin diseases, and as potential therapeutic targets.


Subject(s)
Semaphorins , Skin Diseases , Animals , Semaphorins/metabolism , Signal Transduction , Skin Diseases/etiology
19.
Nutrients ; 15(22)2023 Nov 16.
Article in English | MEDLINE | ID: mdl-38004197

ABSTRACT

Regular physical activity and the use of nutritional supplements, including antioxidants, are recognized as efficacious approaches for the prevention and mitigation of obesity-related complications. This study investigated the effects of 12 weeks of CrossFit training combined with astaxanthin (ASX) supplementation on some plasma adipokines in males with obesity. Sixty-eight males with obesity (BMI: 33.6 ± 1.4 kg·m-2) were randomly assigned into four groups: the control group (CG; n = 11), ASX supplementation group (SG; n = 11), CrossFit group (TG; n = 11), and training plus supplement group (TSG; n = 11). Participants underwent 12 weeks of supplementation with ASX or placebo (20 mg/day capsule daily), CrossFit training, or a combination of both interventions. Plasma levels of semaphorin 3C (SEMA3C), apelin, chemerin, omentin1, visfatin, resistin, adiponectin, leptin, vaspin, and RBP4 were measured 72 h before the first training session and after the last training session. The plasma levels of all measured adipokines were significantly altered in SG, TG, and TSG groups (p < 0.05). The reduction of resistin was significantly higher in TSG than in SG (p < 0.05). The plasma levels of omentin1 were significantly higher in both training groups of TG and TSG than SG (p < 0.05), although such a meaningful difference was not observed between both training groups (p > 0.05). Significant differences were found in the reductions of plasma levels of vaspin, visfatin, apelin, RBP4, chemerin, and SEMA3C between the SG and TSG groups (p < 0.05). The study found that a 12-week intervention using ASX supplementation and CrossFit exercises resulted in significant improvements in several adipokines among male individuals with obesity. Notably, the combined approach of supplementation and training had the most pronounced results. The findings presented in this study indicate that the supplementation of ASX and participation in CrossFit exercise have the potential to be effective therapies in mitigating complications associated with obesity and enhancing metabolic health.


Subject(s)
Adipokines , Semaphorins , Humans , Male , Resistin/metabolism , Apelin , Nicotinamide Phosphoribosyltransferase/metabolism , Obesity , Dietary Supplements , Semaphorins/metabolism , Retinol-Binding Proteins, Plasma
20.
Front Immunol ; 14: 1167605, 2023.
Article in English | MEDLINE | ID: mdl-38022556

ABSTRACT

Background: TGF-ß1 can induce epithelial-mesenchymal transition (EMT) in primary airway epithelial cells (AECs). Semaphorin7A (Sema7a) plays a crucial role in regulating immune responses and initiating and maintaining transforming growth factor ß1 TGF-ß1-induced fibrosis. Objective: To determine the expression of Sema7a, in serum isolated from asthmatics and non-asthmatics, the role of Sema7a in TGF-ß1 induced proliferation, migration and airway EMT in human bronchial epithelial cells (HBECs) in vitro. Methods: The concentrations of Sema7a in serum of asthmatic patients was detected by enzyme-linked immunosorbent assay (ELISA). The expressions of Sema7a and integrin-ß1 were examined using conventional western blotting and real-time quantitative PCR (RT-PCR). Interaction between the Sema7a and Integrin-ß1 was detected using the Integrin-ß1 blocking antibody (GLPG0187). The changes in EMT indicators were performed by western blotting and immunofluorescence, as well as the expression levels of phosphorylated Focal-adhesion kinase (FAK) and Extracellular-signal-regulated kinase1/2 (ERK1/2) were analyzed by western blot and their mRNA expression was determined by RT-PCR. Results: We described the first differentially expressed protein of sema7a, in patients with diagnosed bronchial asthma were significantly higher than those of healthy persons (P<0.05). Western blotting and RT-PCR showed that Sema7a and Integrin-ß1 expression were significantly increased in lung tissue from the ovalbumin (OVA)-induced asthma model. GLPG0187 inhibited TGF-ß1-mediated HBECs EMT, proliferation and migration, which was associated with Focal-adhesion kinase (FAK) and Extracellular-signal-regulated kinase1/2 (ERK1/2) phosphorylation. Conclusion: Sema7a may play an important role in asthma airway remodeling by inducing EMT. Therefore, new therapeutic approaches for the treatment of chronic asthma, could be aided by the development of agents that target the Sema7a.


Subject(s)
Asthma , Semaphorins , Humans , Asthma/metabolism , Epithelial-Mesenchymal Transition , Integrins/metabolism , MAP Kinase Signaling System , Semaphorins/genetics , Semaphorins/metabolism , Signal Transduction , Transforming Growth Factor beta1/metabolism
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