Dendritic Cell Regulation of T Helper Cells.

As the professional antigen-presenting cells of the immune system, dendritic cells (DCs) sense the microenvironment and shape the ensuing adaptive immune response. DCs can induce both immune activation and immune tolerance according to the peripheral cues. Recent work has established that DCs comprise several phenotypically and functionally heterogeneous subsets that differentially regulate T lymphocyte differentiation. This review summarizes both mouse and human DC subset phenotypes, development, diversification, and function. We focus on advances in our understanding of how different DC subsets regulate distinct CD4+ T helper (Th) cell differentiation outcomes, including Th1, Th2, Th17, T follicular helper, and T regulatory cells. We review DC subset intrinsic properties, local tissue microenvironments, and other immune cells that together determine Th cell differentiation during homeostasis and inflammation.

Compartmentalized ocular lymphatic system mediates eye-brain immunity.

The eye, an anatomical extension of the central nervous system (CNS), exhibits many molecular and cellular parallels to the brain. Emerging research demonstrates that changes in the brain are often reflected in the eye, particularly in the retina1. Still, the possibility of an immunological nexus between the posterior eye and the rest of the CNS tissues remains unexplored. Here, studying immune responses to herpes simplex virus in the brain, we observed that intravitreal immunization protects mice against intracranial viral challenge. This protection extended to bacteria and even tumours, allowing therapeutic immune responses against glioblastoma through intravitreal immunization. We further show that the anterior and posterior compartments of the eye have distinct lymphatic drainage systems, with the latter draining to the deep cervical lymph nodes through lymphatic vasculature in the optic nerve sheath. This posterior lymphatic drainage, like that of meningeal lymphatics, could be modulated by the lymphatic stimulator VEGFC. Conversely, we show that inhibition of lymphatic signalling on the optic nerve could overcome a major limitation in gene therapy by diminishing the immune response to adeno-associated virus and ensuring continued efficacy after multiple doses. These results reveal a shared lymphatic circuit able to mount a unified immune response between the posterior eye and the brain, highlighting an understudied immunological feature of the eye and opening up the potential for new therapeutic strategies in ocular and CNS diseases.

IL-10-Dependent Crosstalk between Murine Marginal Zone B Cells, Macrophages, and CD8α+ Dendritic Cells Promotes Listeria monocytogenes Infection.

Type 1 CD8α+ conventional dendritic cells (cDC1s) are required for CD8+ T cell priming but, paradoxically, promote splenic Listeria monocytogenes infection. Using mice with impaired cDC2 function, we ruled out a role for cDC2s in this process and instead discovered an interleukin-10 (IL-10)-dependent cellular crosstalk in the marginal zone (MZ) that promoted bacterial infection. Mice lacking the guanine nucleotide exchange factor DOCK8 or CD19 lost IL-10-producing MZ B cells and were resistant to Listeria. IL-10 increased intracellular Listeria in cDC1s indirectly by reducing inducible nitric oxide synthase expression early after infection and increasing intracellular Listeria in MZ metallophilic macrophages (MMMs). These MMMs trans-infected cDC1s, which, in turn, transported Listeria into the white pulp to prime CD8+ T cells. However, this also facilitated bacterial expansion. Therefore, IL-10-mediated crosstalk between B cells, macrophages, and cDC1s in the MZ promotes both Listeria infection and CD8+ T cell activation.

Dendritic Cells in Food Allergy, Treatment, and Tolerance.

Food allergy is a growing problem with limited treatment options. It is important to understand the mechanisms of food tolerance and allergy to promote the development of directed therapies. Dendritic cells are specialized antigen presenting cells that prime adaptive immune responses, such as those involved in the development of oral tolerance and food allergies. The dendritic cell subsets in the gut and skin are defined by their surface markers and function. The default response to an ingested innocuous antigen is oral tolerance, which requires either gut dendritic cells or a subset of newly identified RORγt+ antigen presenting cells to induce the development of gut peripheral T regulatory cells. However, dendritic cells in the skin, gut, and lung can also promote allergic sensitization when they are activated under certain inflammatory conditions, such as with alarmin release or gut dysbiosis. Dendritic cells also play a role in the responses to the various modalities of food immunotherapy. Langerhans cells in the skin appear to be necessary for the response to epicutaneous immunotherapy. It will be important to determine which real-world stimuli activate the dendritic cells that prime allergic sensitization and discover methods to selectively initiate a tolerogenic program in antigen presenting cells.

Combined gestational age and serum fucose for early prediction of risk for bronchopulmonary dysplasia in premature infants.

OBJECTIVE: As the predominant complication in preterm infants, Bronchopulmonary Dysplasia (BPD) necessitates accurate identification of infants at risk and expedited therapeutic interventions for an improved prognosis. This study evaluates the potential of Monosaccharide Composite (MC) enriched with environmental information from circulating glycans as a diagnostic biomarker for early-onset BPD, and, concurrently, appraises BPD risk in premature neonates. MATERIALS AND METHODS: The study incorporated 234 neonates of ≤32 weeks gestational age. Clinical data and serum samples, collected one week post-birth, were meticulously assessed. The quantification of serum-free monosaccharides and their degraded counterparts was accomplished via High-performance Liquid Chromatography (HPLC). Logistic regression analysis facilitated the construction of models for early BPD diagnosis. The diagnostic potential of various monosaccharides for BPD was determined using Receiver Operating Characteristic (ROC) curves, integrating clinical data for enhanced diagnostic precision, and evaluated by the Area Under the Curve (AUC). RESULTS: Among the 234 neonates deemed eligible, BPD development was noted in 68 (29.06%), with 70.59% mild (48/68) and 29.41% moderate-severe (20/68) cases. Multivariate analysis delineated several significant risk factors for BPD, including gestational age, birth weight, duration of both invasive mechanical and non-invasive ventilation, Patent Ductus Arteriosus (PDA), pregnancy-induced hypertension, and concentrations of two free monosaccharides (Glc-F and Man-F) and five degraded monosaccharides (Fuc-D, GalN-D, Glc-D, and Man-D). Notably, the concentrations of Glc-D and Fuc-D in the moderate-to-severe BPD group were significantly diminished relative to the mild BPD group. A potent predictive capability for BPD development was exhibited by the conjunction of gestational age and Fuc-D, with an AUC of 0.96. CONCLUSION: A predictive model harnessing the power of gestational age and Fuc-D demonstrates promising efficacy in foretelling BPD development with high sensitivity (95.0%) and specificity (94.81%), potentially enabling timely intervention and improved neonatal outcomes.

An outbreak of nosocomial infection of neonatal aseptic meningitis caused by echovirus 18.

We describe an outbreak of echovirus 18 infection involving 10 patients in our neonatal intensive care unit (an attack rate of 33%). The mean age at the onset of illness was 26.8 days. Eighty percent were preterm infants. All were discharged home without sequelae. There were no differences in gestation age, birth weight, delivery mode, use of antibiotics, and parenteral nutrition between the enterovirus (EV) group and non-EV group, but the rate of breastfeeding was significantly higher in the EV group. Separation care and reinforcement of hand-washing seemed to be effective in preventing further spread of the virus. Visiting policy, hygiene practice, and handling of expressed breastmilk should be reinforced.

Oral anaphylaxis to peanut in a mouse model is associated with gut permeability but not with Tlr4 or Dock8 mutations.

BACKGROUND: The etiology of food allergy is poorly understood; mouse models are powerful systems to discover immunologic pathways driving allergic disease. C3H/HeJ mice are a widely used model for the study of peanut allergy because, unlike C57BL/6 or BALB/c mice, they are highly susceptible to oral anaphylaxis. However, the immunologic mechanism of this strain's susceptibility is not known. OBJECTIVE: We aimed to determine the mechanism underlying the unique susceptibility to anaphylaxis in C3H/HeJ mice. We tested the role of deleterious Toll-like receptor 4 (Tlr4) or dedicator of cytokinesis 8 (Dock8) mutations in this strain because both genes have been associated with food allergy. METHODS: We generated C3H/HeJ mice with corrected Dock8 or Tlr4 alleles and sensitized and challenged them with peanut. We then characterized the antibody response to sensitization, anaphylaxis response to both oral and systemic peanut challenge, gut microbiome, and biomarkers of gut permeability. RESULTS: In contrast to C3H/HeJ mice, C57BL/6 mice were resistant to anaphylaxis after oral peanut challenge; however, both strains undergo anaphylaxis with intraperitoneal challenge. Restoring Tlr4 or Dock8 function in C3H/HeJ mice did not protect from anaphylaxis. Instead, we discovered enhanced gut permeability resulting in ingested allergens in the bloodstream in C3H/HeJ mice compared to C57BL/6 mice, which correlated with an increased number of goblet cells in the small intestine. CONCLUSIONS: Our work highlights the potential importance of gut permeability in driving anaphylaxis to ingested food allergens; it also indicates that genetic loci outside of Tlr4 and Dock8 are responsible for the oral anaphylactic susceptibility of C3H/HeJ mice.

Human Blood CD1c+ Dendritic Cells Encompass CD5high and CD5low Subsets That Differ Significantly in Phenotype, Gene Expression, and Functions.

There are three major dendritic cell (DC) subsets in both humans and mice, that is, plasmacytoid DCs and two types of conventional DCs (cDCs), cDC1s and cDC2s. cDC2s are important for polarizing CD4+ naive T cells into different subsets, including Th1, Th2, Th17, Th22, and regulatory T cells. In mice, cDC2s can be further divided into phenotypically and functionally distinct subgroups. However, subsets of human cDC2s have not been reported. In the present study, we showed that human blood CD1c+ cDCs (cDC2s) can be further separated into two subpopulations according to their CD5 expression status. Comparative transcriptome analyses showed that the CD5high DCs expressed higher levels of cDC2-specific genes, including IFN regulatory factor 4, which is essential for the cDC2 development and its migration to lymph nodes. In contrast, CD5low DCs preferentially expressed monocyte-related genes, including the lineage-specific transcription factor MAFB. Furthermore, compared with the CD5low subpopulation, the CD5high subpopulation showed stronger migration toward CCL21 and overrepresentation among migratory DCs in lymph nodes. Additionally, the CD5high DCs induced naive T cell proliferation more potently than did the CD5low DCs. Moreover, CD5high DCs induced higher levels of IL-10-, IL-22-, and IL-4-producing T cell formation, whereas CD5low DCs induced higher levels of IFN-γ-producing T cell formation. Thus, we show that human blood CD1c+ cDC2s encompass two subsets that differ significantly in phenotype, that is, gene expression and functions. We propose that these two subsets of human cDC2s could potentially play contrasting roles in immunity or tolerance.

SCARB2/LIMP-2 Regulates IFN Production of Plasmacytoid Dendritic Cells by Mediating Endosomal Translocation of TLR9 and Nuclear Translocation of IRF7.

Scavenger receptor class B, member 2 (SCARB2) is essential for endosome biogenesis and reorganization and serves as a receptor for both ß-glucocerebrosidase and enterovirus 71. However, little is known about its function in innate immune cells. In this study, we show that, among human peripheral blood cells, SCARB2 is most highly expressed in plasmacytoid dendritic cells (pDCs), and its expression is further upregulated by CpG oligodeoxynucleotide stimulation. Knockdown of SCARB2 in pDC cell line GEN2.2 dramatically reduces CpG-induced type I IFN production. Detailed studies reveal that SCARB2 localizes in late endosome/lysosome of pDCs, and knockdown of SCARB2 does not affect CpG oligodeoxynucleotide uptake but results in the retention of TLR9 in the endoplasmic reticulum and an impaired nuclear translocation of IFN regulatory factor 7. The IFN-I production by TLR7 ligand stimulation is also impaired by SCARB2 knockdown. However, SCARB2 is not essential for influenza virus or HSV-induced IFN-I production. These findings suggest that SCARB2 regulates TLR9-dependent IFN-I production of pDCs by mediating endosomal translocation of TLR9 and nuclear translocation of IFN regulatory factor 7.

PGE2 Elevates IL-23 Production in Human Dendritic Cells via a cAMP Dependent Pathway.

PGE2 elevates IL-23 production in mouse dendritic cells while inhibits IL-23 production in isolated human monocytes. Whether this differential effect of PGE2 on IL-23 production is cell-type- or species-specific has not been investigated in detail. The present study was designed to investigate the effect of PGE2 on IL-23 production in human DCs and the possible underlying mechanisms. Human monocytes derived dendritic cells (Mo-DCs) were pretreated with or without PGE2. Then the cells were incubated with zymosan. Our results demonstrated that PGE2 promoted zymosan-induced IL-23 production in a concentration dependent manner. In addition, it was found that PGE2 is also able to elevate MyD88-mediated IL-23 p19 promoter activity. More importantly, ELISA data demonstrated that db-cAMP, a cAMP analog, and forskolin, an adenylate cyclase activator, can mimic the effect of PGE2 on zymosan-induced IL-23 production, and rp-cAMP, a protein kinase A (PKA) inhibitor, can block the effect of PGE2. Moreover, PGE2 can increase zymosan-induced expression of the mRNA levels of both p19 and p40 subunits, which was mimicked by db-cAMP and forskolin. Our data suggest that PGE2 elevates the production of IL-23 in human Mo-DCs via a cAMP dependent pathway.

X-linked intellectual developmental disorder with onset of neonatal heart failure: A case report and literature review.

X-linked intellectual developmental disorder is a rare X-linked genetic disease, manifested as heart disease, intellectual impairment, and developmental disorders. We report a male infant who presented with dyspnea after birth. Physical examination on admission revealed poor responsiveness, deep eye sockets, a small mandible, abnormalities of the outer ears, and reduced limb muscle tone. The child was moaning with shortness of breath and a positive three-concave sign without pulmonary rales. The heart sounds were weak with a grade 2/6 diastolic heart murmur. Echocardiography showed an enlarged heart with increased trabeculae in the left ventricular muscle wall. X-linked mental retardation syndrome type 34(MRXS34, OMIM# 300967) was diagnosed after exome sequencing showed a c.1131G > A hemizygous variant in the NONO gene. After timely therapy including respiratory support, cardiac glycosides, and diuresis, the child's condition improved and he was discharged at one month of age. A literature review showed that, to date, 22 live births with X-linked mental retardation have been reported. The NONO-related phenotype can be summarized as a neurological and cardiac developmental disorder, which may be accompanied by multisystem malformations. The present case enriches the knowledge of X-linked intellectual developmental syndromes.

Metabolic fitness of IgA+ plasma cells in the gut requires DOCK8.

Dedicator of cytokinesis 8 (DOCK8) mutations lead to a primary immunodeficiency associated with recurrent gastrointestinal infections and poor antibody responses but, paradoxically, heightened IgE to food antigens, suggesting that DOCK8 is central to immune homeostasis in the gut. Using Dock8-deficient mice, we found that DOCK8 was necessary for mucosal IgA production to multiple T cell-dependent antigens, including peanut and cholera toxin. Yet DOCK8 was not necessary in T cells for this phenotype. Instead, B cell-intrinsic DOCK8 was required for maintenance of antigen-specific IgA-secreting plasma cells (PCs) in the gut lamina propria. Unexpectedly, DOCK8 was not required for early B cell activation, migration, or IgA class switching. An unbiased interactome screen revealed novel protein partners involved in metabolism and apoptosis. Dock8-deficient IgA+ B cells had impaired cellular respiration and failed to engage glycolysis appropriately. These results demonstrate that maintenance of the IgA+ PC compartment requires DOCK8 and suggest that gut IgA+ PCs have unique metabolic requirements for long-term survival in the lamina propria.

VEGF-C prophylaxis favors lymphatic drainage and modulates neuroinflammation in a stroke model.

Meningeal lymphatic vessels (MLVs) promote tissue clearance and immune surveillance in the central nervous system (CNS). Vascular endothelial growth factor-C (VEGF-C) regulates MLV development and maintenance and has therapeutic potential for treating neurological disorders. Herein, we investigated the effects of VEGF-C overexpression on brain fluid drainage and ischemic stroke outcomes in mice. Intracerebrospinal administration of an adeno-associated virus expressing mouse full-length VEGF-C (AAV-mVEGF-C) increased CSF drainage to the deep cervical lymph nodes (dCLNs) by enhancing lymphatic growth and upregulated neuroprotective signaling pathways identified by single nuclei RNA sequencing of brain cells. In a mouse model of ischemic stroke, AAV-mVEGF-C pretreatment reduced stroke injury and ameliorated motor performances in the subacute stage, associated with mitigated microglia-mediated inflammation and increased BDNF signaling in brain cells. Neuroprotective effects of VEGF-C were lost upon cauterization of the dCLN afferent lymphatics and not mimicked by acute post-stroke VEGF-C injection. We conclude that VEGF-C prophylaxis promotes multiple vascular, immune, and neural responses that culminate in a protection against neurological damage in acute ischemic stroke.

Escape from the pore.

Perforin-2 mediates endocytic escape in cross-presenting dendritic cells.

Combining bulk RNA-sequencing and single-cell RNA-sequencing data to reveal the immune microenvironment and metabolic pattern of osteosarcoma.

Background: Osteosarcoma (OS) is a kind of solid tumor with high heterogeneity at tumor microenvironment (TME), genome and transcriptome level. In view of the regulatory effect of metabolism on TME, this study was based on four metabolic models to explore the intertumoral heterogeneity of OS at the RNA sequencing (RNA-seq) level and the intratumoral heterogeneity of OS at the bulk RNA-seq and single cell RNA-seq (scRNA-seq) level. Methods: The GSVA package was used for single-sample gene set enrichment analysis (ssGSEA) analysis to obtain a glycolysis, pentose phosphate pathway (PPP), fatty acid oxidation (FAO) and glutaminolysis gene sets score. ConsensusClusterPlus was employed to cluster OS samples downloaded from the Target database. The scRNA-seq and bulk RNA-seq data of immune cells from GSE162454 dataset were analyzed to identify the subsets and types of immune cells in OS. Malignant cells and non-malignant cells were distinguished by large-scale chromosomal copy number variation. The correlations of metabolic molecular subtypes and immune cell types with four metabolic patterns, hypoxia and angiogenesis were determined by Pearson correlation analysis. Results: Two metabolism-related molecular subtypes of OS, cluster 1 and cluster 2, were identified. Cluster 2 was associated with poor prognosis of OS, active glycolysis, FAO, glutaminolysis, and bad TME. The identified 28608 immune cells were divided into 15 separate clusters covering 6 types of immune cells. The enrichment scores of 5 kinds of immune cells in cluster-1 and cluster-2 were significantly different. And five kinds of immune cells were significantly correlated with four metabolic modes, hypoxia and angiogenesis. Of the 28,608 immune cells, 7617 were malignant cells. The four metabolic patterns of malignant cells were significantly positively correlated with hypoxia and negatively correlated with angiogenesis. Conclusion: We used RNA-seq to reveal two molecular subtypes of OS with prognosis, metabolic pattern and TME, and determined the composition and metabolic heterogeneity of immune cells in OS tumor by bulk RNA-seq and single-cell RNA-seq.

Infantile Pompe disease with intrauterine onset: a case report and literature review.

BACKGROUND: Pompe disease is a rare autosomal recessive disease. Acid alpha-glucosidase (GAA) deficiency leads to glycogen storage in lysosomes, causing skeletal, cardiac, and smooth muscle lesions. Pompe disease is progressive, and its severity depends on the age of onset. Classic infantile Pompe disease, the most severe form, is characterized by an age of onset before 12 months. Pompe disease with intrauterine onset has rarely been reported. CASE PRESENTATION: The proband was born at a gestational age of 40 weeks and 3 days and admitted to our hospital because of intrauterine cardiac hypertrophy, shortness of breath, and cyanosis until 13 min postnatally. Physical examination at admission revealed poor responsiveness, pale skin, shortness of breath, reduced limb muscle tone, and bilateral pedal edema. The heart sounds were weak, and no heart murmur was heard. Echocardiography showed left (9 mm) and right (5 mm) ventricular hypertrophies. The patient was subjected to non-invasive ventilator-assisted respiration, fluid restriction, diuresis, and metoprolol treatment. Infantile Pompe disease was diagnosed on day 16 with a GAA enzymatic activity of 0.31 µmol/L/h and with the full-penetrance genetic test showing the homozygous gene mutation c.1844G>T(p.Gly615Val). Enzyme replacement therapy was refused by the patient's parents, and the patient died at seven months of age from cardiopulmonary failure. CONCLUSION: Infants with intrauterine-onset Pompe disease usually have early manifestations of heart disease. Prompt GAA enzymatic activity determination and molecular genetic testing are helpful in aiding the parents' decision and planning the treatment.

[Expression of estrogen receptor alpha in the testis of infertile men with spermatogenic arrest].

OBJECTIVE: To explore the association of spermatogenic arrest with the expression of estrogen receptor alpha (ERalpha) in human testes. METHODS: We examined the testicular biopsy specimens of 120 infertile men by HE staining, detected the expression of ERalpha in the specimens of those with spermatogenic arrest by the two-step immunohistochemical method, and compared the results with those of 10 healthy men. RESULTS: Of the 120 specimens from the infertile men, 31 (25.8%) met the diagnostic criteria of spermatogenic arrest. In the testis tissue of normal men, ERalpha expressed in Sertoli, myoid and Leydig cells, but not in spermatogenic cells, while in the testis tissues of those with spermatogenic arrest, ERalpha expressed lowly in Sertoli, myoid and Leydig cells, with statistically significant differences in immunostaining intensity between the two groups (P < 0.05). CONCLUSION: Androgen receptor (AR) and ERalpha may play a coordinating role in facilitating spermatogenesis. Spermatogenic arrest may be related to a complex series of disorders in cell signal transduction involving AR, ERalpha and HSP90.

Preparation of cellulose nanospheres via combining ZnCl2·3H2O pretreatment and p-toluenesulfonic hydrolysis as a two-step method.

Spherical nanocelluloses, also known as cellulose nanospheres (CNS), have controllable morphology and have shown advantages as green template material, emulsion stabilizer. Herein, CNS were prepared via a new two-step method, first pretreatment of microcrystalline cellulose (MCC) using ZnCl2·3H2O and then acid hydrolysis of regenerated cellulose (RC) via p-toluenesulfonic acid (p-TsOH). The shape, size, crystallinity of MCC were changed, and nubbly RC with smallest size (942 nm) was obtained after 2 h pretreatment by ZnCl2·3H2O. CNS with high 61.3% yield were produced after acid hydrolysis (67 wt% p-TsOH) of RC at 80 °C, 6 h. The analysis of Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) showed that CNS had an average diameter of 347 nm. CNS were present in precipitate after high-speed centrifugation, due to the high Zeta potential of -12 mV and large size. The structure of CNS was tested by Fourier Transfer Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Nuclear Magnetic Resonance (NMR), CNS had high crystallinity (cellulose II) of 61%. Thermal Gravimetric Analysis (TGA) indicated that CNS had high thermal stability (Tonset 303.3 °C, Tmax 332 °C). CNS showed poor re-dispersibility in water/ethanol/THF, 1 wt% CNS could be dissolved in ZnCl2·3H2O. 7.37% rod-like CNC were obtained after 6 h hydrolysis. FTIR proved that p-TsOH was recovered by re-crystallization. This study provided a novel, sustainable two-step method for the preparation of spherical CNS.

Torn between type 1 and type 2 immunity.

DOCK8 uncovers a link between cell integrity and TH2 skewing.

Antigen-Presenting Cells in Food Tolerance and Allergy.

Food allergy now affects 6%-8% of children in the Western world; despite this, we understand little about why certain people become sensitized to food allergens. The dominant form of food allergy is mediated by food-specific immunoglobulin E (IgE) antibodies, which can cause a variety of symptoms, including life-threatening anaphylaxis. A central step in this immune response to food antigens that differentiates tolerance from allergy is the initial priming of T cells by antigen-presenting cells (APCs), primarily different types of dendritic cells (DCs). DCs, along with monocyte and macrophage populations, dictate oral tolerance versus allergy by shaping the T cell and subsequent B cell antibody response. A growing body of literature has shed light on the conditions under which antigen presentation occurs and how different types of T cell responses are induced by different APCs. We will review APC subsets in the gut and discuss mechanisms of APC-induced oral tolerance versus allergy to food identified using mouse models and patient samples.