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The complement-dendritic cell-endothelial cell crosstalk in vascular inflammation
No full textInflammation is a highly co-ordinated process involving multiple immune components, including the complement system, dendritic cells (DCs), and endothelial cells (ECs). All of them play pivotal roles in immunity and host defence and have a significant impact on cardiovascular health and disease. While individual functions of the complement system, DCs and ECs are well-characterized, their multifaceted interplay in modulating inflammation and disease is insufficiently elucidated. The complement system exerts predominantly pro-inflammatory effects, influencing the immune, cardiovascular, and nervous systems. DCs bridge innate and adaptive immunity, shaping T-cell and B-cell responses depending on their maturation state. At the interface between tissues and circulation, ECs regulate immune cell trafficking and vascular homeostasis, while endothelial dysfunction or injury contributes to cardiovascular disorders such as atherosclerosis, hypertension, heart failure, or acute thrombotic events. We have to understand the dynamic crosstalk between the complement system, DCs and ECs, which are important for cardiovascular systems biology, to be able to identify new research avenues and potential therapeutic strategies. This article reviews current insights into these molecular networks, discussing their impact on inflammation and cardiovascular pathology. By elucidating these mechanisms, innovative approaches to prevent and manage cardiovascular diseases may emerge
Microglial expression of serotonin receptors reveals parallel regulation of 5-HT2b and BDNF in the rat hippocampus
Get PDFGrowing evidence suggests that psychiatric disorders are characterized by a prolonged inflammatory state, which may influence the efficacy of compounds targeting serotonin. Serotonin is a key signaling molecule in neuroplasticity of the adult hippocampus and involved in antidepressant action. Recent in vitro studies indicate the neurotransmitter may also facilitate the response to inflammation and potentially modulate microglial function towards neuroprotection. Using Tph2(−/−) rats depleted of brain serotonin, we examined microglial expression of various serotonin receptors (5-HTRs) in vivo in both the hippocampus and prefrontal cortex and assessed mRNA levels of cytokines and brain-derived neurotrophic factor (BDNF). We observed age-dependent and region-specific gene expression of 5-HTRs on sorted microglia, paralleling changes in BDNF signaling, especially with 5-HT2b. Notably, both 5-HT2b and BDNF expression in the hippocampus was significantly upregulated in the absence of brain serotonin. Our data indicate distinct roles of 5-HTR subtypes in early network formation (5-HT1b, 5-HT5b) and in the response to endogenous changes (5-HT2b, 5-HT5a). Understanding serotonin–microglia interplay could offer therapeutic insights into the maintenance of mood via brain–immune cell interactions
Multi-omics analysis reveals vitamin D metabolism, hyper-IgE genes, and epithelial barrier dysfunction in hazelnut allergy
Get PDFBACKGROUND: Hazelnut allergy is a major cause of food-induced anaphylaxis yet remains poorly defined at the molecular level. OBJECTIVE: We aimed to identify molecular differences between individuals with primary hazelnut allergy and nonallergic controls by investigating a comprehensive spectrum of omics profiles in immune cells. METHODS: We analysed DNA methylation, transcriptomic and proteomic profiles in hazelnut-stimulated and unstimulated immune cells. RESULTS: Across analyses, we identified 80 differentially methylated signatures, 125 differentially expressed genes, and 11 differentially secreted proteins associated with hazelnut allergy. DNA methylation signatures were highly concordant between unstimulated and stimulated conditions, consistent with stable epigenetic remodelling. Key findings implicated ZNF341, associated with a rare monogenic hyper-IgE syndrome, and ARL2, both linked to STAT3-mediated IgE dysregulation. Additionally, we identified a differentially methylated region (DMR) overlapping the T Helper Type 2 Locus Control Region Associated RNA (TH2LCRR) in the cytokine gene cluster, suggesting an epigenetic mechanism contributing to IL-5 and IL-13 upregulation. Antigen stimulation was required to reveal hazelnut-specific transcriptional and proteomic signals. Integration of these data demonstrated that IL-5 expression could distinguish both groups. We identified signals in epithelial barrier genes of the gut and skin (TRIM31, TRIM40, CDSN), activation of the vitamin D pathway (CYP27B1, IL32), and nominate additional signals (PHACTR1, MFHAS1, SPRED2, GALNT5/GALNTL4, NSMCE1-DT) for follow-up. CONCLUSION: Our study confirms type-2 cytokines, FcEpsilonRI, and JAK-STAT signalling and uncovers novel links to monogenic hyper-IgE syndrome, activation of vitamin-D pathways, and gut/skin barrier genes, yielding a catalogue of candidate biomarkers for mechanistic studies and prospective validation
Topology control by a conserved cysteine pair in the OMM-protein CCDC127 enables MICOS interaction
Get PDFMitochondrial disulfide relay substrates beyond the canonical substrates remain incompletely defined. Revisiting the human MIA40 interactome with enhanced depth, we identified CCDC127 as a previously unrecognized substrate candidate. CCDC127 contains a single transmembrane segment and a conserved C-terminal helical bundle domain (CHB). Comprehensive proteomic and biochemical analyses revealed that, contrary to earlier reports, CCDC127 adopts an N(out)–C(in) topology in the outer mitochondrial membrane (OMM) with its CHB residing in the intermembrane space (IMS). CCDC127 undergoes oxidation by the disulfide relay, forming a long-range intramolecular disulfide bond between C174 and C219. Loss of these cysteines disrupts correct OMM insertion, inverts transmembrane topology and triggers proteasome-dependent degradation, establishing the disulfide as a key determinant of CCDC127 maturation. Interactome analyses identified MICOS components— particularly the MIC60/MIC19 module—as major partner proteins required for the stability of large oligomeric CCDC127 complexes. CCDC127 deficiency impaired cellular proliferation, influenced phospholipid levels, and caused grossly altered cristae morphology. Together, CCDC127 emerges as a MICOS-associated OMM protein essential for mitochondrial membrane organization and lipid homeostasis
Examining the healthy human microbiome concept
No full textHuman microbiomes are essential to health throughout the lifespan and are increasingly recognized and studied for their roles in metabolic, immunological and neurological processes. Although the full complexity of these microbial communities is not fully understood, their clinical and industrial exploitation is well advanced and expanding, needing greater oversight guided by a consensus from the research community. One of the most controversial issues in microbiome research is the definition of a ‘healthy’ human microbiome. This concept is complicated by the microbial variability over different spatial and temporal scales along with the challenge of applying a unified definition to the spectrum of healthy microbiome configurations. In this Perspective, we examine the progress made and the key gaps that remain to be addressed to fully harness the benefits of the human microbiome. We propose a road map to expand our knowledge of the microbiome–health relationship, incorporating epidemiological approaches informed by the unique ecological characteristics of these communities
Direct specification of lymphatic endothelium from mesenchymal progenitors
Get PDFDuring embryogenesis, endothelial cells (ECs) are generally described to arise from a common pool of progenitors termed angioblasts, which diversify through iterative steps of differentiation to form functionally distinct subtypes of ECs. A key example is the formation of lymphatic ECs (LECs), which are thought to arise largely through transdifferentiation from venous endothelium. Opposing this model, here we show that the initial expansion of mammalian LECs is primarily driven by the in situ differentiation of mesenchymal progenitors and does not require transition through an intermediate venous state. Single-cell genomics and lineage-tracing experiments revealed a population of paraxial mesoderm-derived Etv2(+)Prox1(+) progenitors that directly give rise to LECs. Morphometric analyses of early LEC proliferation and migration, and mutants that disrupt lymphatic development supported these findings. Collectively, this work establishes a cellular blueprint for LEC specification and indicates that discrete pools of mesenchymal progenitors can give rise to specialized subtypes of ECs
Gene-editing in patient and humanized-mice primary muscle stem cells rescues dysferlin expression in dysferlin-deficient muscular dystrophy
Get PDFDystrophy-associated fer-1-like protein (dysferlin) conducts plasma membrane repair. Mutations in the DYSF gene cause a panoply of genetic muscular dystrophies. We targeted a frequent loss-of-function, DYSF exon 44, founder frameshift mutation with mRNA-mediated delivery of SpCas9 in combination with a mutation-specific sgRNA to primary muscle stem cells from two homozygous patients. We observed a consistent >60% exon 44 re-framing, rescuing a full-length and functional dysferlin protein. A new mouse model harboring a humanized Dysf exon 44 with the founder mutation, hEx44mut, recapitulates the patients’ phenotype and an identical re-framing outcome in primary muscle stem cells. Finally, gene-edited murine primary muscle stem-cells are able to regenerate muscle and rescue dysferlin when transplanted back into hEx44mut hosts. These findings are the first to show that a CRISPR-mediated therapy can ameliorate dysferlin deficiency. We suggest that gene-edited primary muscle stem cells could exhibit utility, not only in treating dysferlin deficiency syndromes, but also perhaps other forms of muscular dystrophy
The proline-rich antimicrobial peptide Api137 disrupts large ribosomal subunit assembly and induces misfolding
Get PDFThe proline-rich antimicrobial designer peptide Api137 inhibits protein expression in bacteria by binding simultaneously to the ribosomal polypeptide exit tunnel and the release factor (RF), depleting the cellular RF pool and leading to ribosomal arrest at stop codons. This study investigates the additional effect of Api137 on the assembly of ribosomes using an Escherichia coli reporter strain expressing one ribosomal protein per 30S and 50S subunit tagged with mCherry and EGFP, respectively. Separation of cellular extracts derived from cells exposed to Api137 in a sucrose gradient reveals elevated levels of partially assembled and not fully matured precursors of the 50S subunit (pre-50S). High-resolution structures obtained by cryogenic electron microscopy demonstrate that a large proportion of pre-50S states are missing up to five proteins (uL22, bL32, uL29, bL23, and uL16) and have misfolded helices in 23S rRNA domain IV. These data suggest a second mechanism for Api137, wherein it disrupts 50S subunit assembly by inducing the formation of misfolded precursor particles potentially incapable of evolving into active ribosomes, suggesting a bactericidal mechanism
Engineering therapeutic regulatory T cells to overexpress G protein-coupled receptor 15 improves functional fitness for in vivo gut homing
Get PDFRenal damage-induced hepcidin accumulation contributes to anemia in angiotensinogen-deficient mice
Get PDFAngiotensin II (Ang II) is the most active peptide hormone produced by the renin–angiotensin system (RAS). Genetic deletion of genes that ultimately restrict Ang II formation has been shown to result in marked anemia in mice. In this study, adult mice with a genetic deletion of the RAS precursor protein angiotensinogen (Agt-KO) were used. Experimental analyses included capillary hematocrit, hemogram, plasma and tissue iron quantifications, expression analyses of genes encoding relevant proteins for body iron homeostasis in different organs, as well as plasma and urine hepcidin quantifications. As previously reported, Agt-KO were anemic with reduced red blood cell counts. Interestingly, we found that they presented microcytic anemia based on the reduced red blood cell volume. In agreement, plasma quantification of iron revealed lower levels of circulating iron in Agt-KO. The major body iron stores, namely in the liver and spleen, were also depleted in the RAS-deficient line. Hepatic hepcidin expression was reduced, as well as one of its major regulators, BMP6, as a result of the iron deficiency. However, plasma hepcidin levels were unexpectedly increased in Agt-KO. We confirm the typical morphological alterations and impaired renal function of Agt-KO and conclude that hepcidin accumulates in the circulation due to the reduced glomerular filtration in Agt-KO, and therefore identified the culprit of iron deficiency in Agt-KO. Collectively, the data demonstrated that the severe anemia developed in RAS-deficient mice is exacerbated by iron deficiency which is secondary to the renal damage-induced hepcidin accumulation in the circulation