The spleen is a separate organ of the teleost, playing an essential role in immune reactions. The morphology of the spleen is different from the fish species. Little knowledge about the spleen structure and the blood splenic barrier (BSB) in Nile tilapia has been reported. To address this issue, we studied the histology of the spleen and the BSB in healthy Nile tilapia. The morphology of the spleen was observed, then H&E staining, modified Jame's staining, and ultrastructural techniques were performed to portion the spleen into three subregions and analyze the location of components and fibers. Thereafter, vital staining of Nile tilapia with Trypan blue was conducted to elucidate the composition and function of BSB. Histologically, the spleen could be divided into three subregions (inner, middle, and outer). The venules, clumps of lymphocytes, and vessels were separately characterized features of the outer, middle, and inner layers. Post injection, Trypan blue was intercepted in the endotheliocytes of ellipsoids in the middle layer (i.p.) or was deposited to the reticular fibers surrounding the ellipsoids (i.v.). Additionally, the amount of Trypan blue was shown to be positively correlated to that of the Acid phosphatase expressed. In conclusion, the spleen could be portioned into three subregions, and the BSB lay in the middle layer, composed of the cuboidal-shaped endotheliocytes and the surrounding reticular fibers of the ellipsoid capillaries. The present study enriched the research of immune tissues and system in tilapia and provided reference for the study of spleen in other fish species.

A previous study demonstrated that nearly 40%-60% of brain Aβ flows out into the peripheral system for clearance. However, where and how circulating Aβ is cleared in the periphery remains unclear. The spleen acts as a blood filter and an immune organ. The aim of the present study was to investigate the role of the spleen in the clearance of Aβ in the periphery.

To investigate the effect of magnetic nanoparticles (MNPs) of Fe(3)O(4) combined with cyclosporin A (CsA) on acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in murine models.

Intercellular adhesion molecule-1 (ICAM-1) is a key adhesion molecule mediating neutrophil migration and infiltration during sepsis. But its role in the outcome of sepsis remains contradictory. The current study was performed to investigate the role of anti-ICAM-1 antibody in the outcome of polymicrobial sepsis and sepsis-induced immune disturbance. Effect of anti-ICAM-1 antibody on outcome of sepsis induced by cecal ligation and puncture (CLP) was evaluated by the survival analysis, bacterial clearance, and lung injury. Its influence on neutrophil migration and infiltration, as well as lymphocyte status, in thymus and spleen was also investigated. The results demonstrated that ICAM-1 mRNA was upregulated in lung, thymus, and spleen of CLP mice. Anti-ICAM-1 antibody improved survival and bacterial clearance in CLP mice and attenuated lung injury. Migration of neutrophils to peritoneal cavity was enhanced while their infiltration into lung, thymus, and spleen was hampered by ICAM-1 blockade. Anti-ICAM-1 antibody also prevented sepsis-induced apoptosis in thymus and spleen. Positive costimulatory molecules including CD28, CD80, and CD86 were upregulated, while negative costimulatory molecules including PD-1 and PD-L1 were downregulated following anti-ICAM-1 antibody administration. In conclusion, ICAM-1 blockade may improve outcome of sepsis. The rationale may include the modulated neutrophil migration and the reversed immunosuppression.

Leucism, a widespread occurrence observed in Northern snakehead (Channa argus), bestows a striking white jade-like body coloration upon affected individuals and has gained substantial popularity in commercial breeding. While the visible manifestation of leucism in snakeheads is primarily limited to body coloration, it is crucial to explore the potential influence of leucism on organ development and elucidate the underlying molecular mechanisms. Through a comparative analysis of growth differences, our study revealed that at 150 days post-fertilization, the white variety exhibited an 8.5% higher liver index and intestinal index, but experienced a 20% and 38% decreased in spleen index and renal interstitial index, respectively, suggesting an enlarged digestive area but relatively smaller immune tissues. Nonetheless, no significant differences were observed in the intestinal flora between the two varieties, suggesting the exclusion of any exogenous impacts from symbiotic flora on the growth and development of the white variety. Importantly, transcriptome analysis demonstrated that the white variety exhibited higher expression levels of innate immune genes. Furthermore, annotation of the gene sets expressed in the liver and spleen revealed 76 and 35 genes respectively, with the white variety displaying lower expression in genes associated with "Viral protein interaction with cytokine and cytokine receptor", "Protein processing in endoplasmic reticulum", and "TNF signaling pathway", while exhibiting higher expression in "Estrogen signaling pathway". Notably, three genes, namely pcdhf 4, nlrc3 card 15-like, and a pol-like were identified in both the liver and spleen, indicating their potential involvement in altering the development and innate immunity of the white variety. This study reveals the systemic impact of leucism that extends beyond mere pigmentation alterations, highlighting the prominent characteristics of this phenotype and providing a foundation for future molecular breeding programs aimed at enhancing this variety.

Depression is a serious public-health issue. Recent reports have suggested higher susceptibility to viral infections in depressive patients. However, how depression affects antiviral innate immune signaling remains unknown. Here, we revealed a reduction in expression of Abelson helper integration site 1 (AHI1) in the peripheral blood mononuclear cells (PBMCs) and macrophages from the patients with major depressive disorder (MDD), which leads to attenuated antiviral immune response. We found that depression-related arginine vasopressin (AVP) induces reduction of AHI1 in macrophages. Further studies demonstrated that AHI1 is a critical stabilizer of basal type-I-interferon (IFN-I) signaling. Mechanistically, AHI1 recruits OTUD1 to deubiquitinate and stabilize Tyk2, while AHI1 reduction downregulates Tyk2 and IFN-I signaling activity in macrophages from both MDD patients and depression model mice. Interestingly, we identified a clinical analgesic meptazinol that effectively stimulates AHI1 expression, thus enhancing IFN-I antiviral defense in depression model mice. Our study promotes the understanding of the signaling mechanisms of depression-mediated antiviral immune dysfunction, and reveals meptazinol as an enhancer of antiviral innate immunity in depressive patients.

Duck viral enteritis is a highly contagious and fatal disease of commercial waterfowl flocks. The disease occurs sporadically or epizootically in mainland China due to insufficient vaccinations. Early and rapid diagnosis is important for preventive intervention and the control of epizootic events in clinical settings. In this study, we generated two monoclonal antibodies (MAbs) that specifically recognized the duck enteritis virus (DEV) envelope glycoprotein B and tegument protein UL47, respectively. Using these MAbs, a colloidal gold-based immunochromatographic assay (ICA) was developed for the efficient detection of DEV antigens within 15 min. Our results showed that the detection limit of the developed ICA strip was 2.52 × 103 TCID50/mL for the virus infected cell culture suspension with no cross-reactivity with other pathogenic viruses commonly encountered in commercially raised waterfowl. Using samples from experimentally infected ducks, we demonstrated that the ICA detected the virus in cloacal swab samples on day three post-infection, demonstrating an 80% concordance with the PCR. For tissue homogenates from ducks succumbing to infection, the detection sensitivity was 100%. The efficient and specific detection by this ICA test provides a valuable, convenient, easy to use and rapid diagnostic tool for DVE under both laboratory and field conditions.

Salidroside, isolated from the medicinal plant Rhodiola, was reported to serve as an "adaptogen." This study was designed to explore the protective effect of salidroside on concanavalin A- (Con A-) induced hepatitis in mice and investigate potential mechanisms. C57BL/6 mice were randomly divided into control group, Con A group, and salidroside group. Salidroside (50 mg/kg) was injected intravenously followed by Con A administration. The levels of ALT, AST, inflammatory cytokines and CXCL-10 were examined. The pathological damage of livers was assessed, the amounts of phosphorylated IκBα and p65 were measured, and the numbers of CD4(+) and CD8(+) T lymphocytes in the blood, spleen and infiltrated in the liver were calculated. Our results showed that salidroside pretreatment reduced the levels of ALT, AST dramatically and suppressed the secretion of proinflammatory cytokines through downregulating the activity of NF-κB partly. Salidroside altered the distribution of CD4(+) and CD8(+) T lymphocyte in the liver and spleen through regulating CXCL-10 and decreased the severity of liver injuries. In conclusion, these results confirm the efficacy of salidroside in the prevention of immune mediated hepatitis in mice.

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. Its pathological features are dopaminergic neuronal death in the substantia nigra (SN), and significant reduction in dopamine (DA) content in the striatum. A large number of studies have found an increase in iron levels in PD patients and animal models, which suggested that brain iron metabolism dysfunction played a key role in the pathogenesis of PD. Lactoferrin (Lf) is a non-heme iron-binding glycoprotein belonging to the transferrin family, entering the cell membrane via a lactoferrin receptor-mediated pathway. Lf exists mainly in two forms: iron-free-lactoferrin (apo-Lf) and iron-saturated-lactoferrin (holo-Lf). Our previous studies found thatapo-Lf and holo-Lf exert neuroprotective effects against 1-methyl-4-phenylpyridinium toxicity in ventral mesencephalon neurons in vitro. This study aimed to further investigate whether two different forms of Lf have neuroprotective effects in vivo, and to examine their mechanisms, so as to provide an experimental basis for finding new therapeutic strategies against PD. In the central nervous system, Lf antagonized 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced DA depletion in the striatum, iron deposition, oxidative, and apoptotic processes in the SN. Lf treatment down-regulated iron import protein divalent metal transporter1 and up-regulated iron export protein ferroportin1, attenuating MPTP-induced accumulation of nigral iron level. In the peripheral system, Lf alleviated MPTP-induced increases in serum iron and ferritin, and decreases in serum total iron-binding capacity, loss of spleen weight, and reduction in spleen iron content. The results indicate that Lf has a neuroprotective effect on MPTP-induced PD model mice, and its mechanism may be related to anti-iron dysregulation, anti-oxidative stress, and anti-apoptosis, with apo-Lf showing greater efficacy. Therefore, Lf might be a promising therapeutic substance for PD. Open Science: This manuscript was awarded with the Open Materials Badge For more information see: https://cos.io/our-services/open-science-badges/.

Migration to intestinal mucosa putatively depends on local activation because gastrointestinal lymphoid tissue induces expression of intestinal homing molecules, whereas skin-draining lymph nodes do not. This paradigm is difficult to reconcile with reports of intestinal T cell responses after alternative routes of immunization. We reconcile this discrepancy by demonstrating that activation within spleen results in intermediate induction of homing potential to the intestinal mucosa. We further demonstrate that memory T cells within small intestine epithelium do not routinely recirculate with memory T cells in other tissues, and we provide evidence that homing is similarly dynamic in humans after subcutaneous live yellow fever vaccine immunization. These data explain why systemic immunization routes induce local cell-mediated immunity within the intestine and indicate that this tissue must be seeded with memory T cell precursors shortly after activation.

Bone marrow mesenchymal stem cells (BMSC) transfer has been attempted as a therapeutic strategy in experimental lung injury and fibrosis. Reduction of neutrophilic infiltration is one of the mechanisms involved in this effect. However, the mechanisms by which BMSC modulate neutrophil remains unknown.

Helminth-derived products have recently been shown to prevent the development of inflammatory diseases in mouse models. However, most identified immunomodulators from helminthes are mixtures or macromolecules with potentially immunogenic side effects. We previously identified an immunomodulatory peptide called SJMHE1 from the HSP60 protein of Schistosoma japonicum. In this study, we assessed the ability of SJMHE1 to affect murine splenocytes and human peripheral blood mononuclear cells (PBMCs) stimulated by toll-like receptor (TLR) ligands in vitro and its treatment effect on mice with collagen-induced arthritis (CIA). We show that SJMHE1 not only modulates the cytokine production of murine macrophage (MΦ) and dendritic cell but also affects cytokine production upon coculturing with allogeneic CD4+ T cell. SJMHE1 potently inhibits the cytokine response to TLR ligands lipopolysaccharide (LPS), CpG oligodeoxynucleotides (CpG) or resiquimod (R848) from mouse splenocytes, and human PBMCs stimulated by LPS. Furthermore, SJMHE1 suppressed clinical signs of CIA in mice and blocked joint erosion progression. This effect was mediated by downregulation of key cytokines involved in the pathogenesis of CIA, such as interferon-γ (IFN-γ), tumour necrosis factor-α (TNF-α), interleukin (IL)-6, IL-17, and IL-22 and up-regulation of the inhibitory cytokine IL-10, Tgf-β1 mRNA, and CD4+ CD25+ Foxp3+ Tregs. This study provides new evidence that the peptide from S. japonicum, which is the 'safe' selective generation of small molecule peptide that has evolved during host-parasite interactions, is of great value in the search for novel anti-inflammatory agents and therapeutic targets for autoimmune diseases.

Hypoxia-induced pulmonary hypertension (HPH) is a fatal cardiovascular disease characterized by an elevation in pulmonary artery pressure, resulting in right ventricular dysfunction and eventual heart failure. Exploring the pathogenesis of HPH is crucial, and small noncoding RNAs (sncRNAs) are gaining recognition as potential regulators of cellular responses to hypoxia. In this study, we conducted a comprehensive analysis of sncRNA profiles in eight tissues of male HPH rats using high-throughput sequencing. Our study unveiled several sncRNAs, with the brain, kidney, and spleen exhibiting the highest abundance of microRNA (miRNA), tRNA-derived small RNA (tDR), and small nucleolar RNA (snoRNA), respectively. Moreover, we identified numerous tissue-specific and hypoxia-responsive sncRNAs, particularly miRNAs and tDRs. Interestingly, we observed arm switching in miRNAs under hypoxic conditions and a significant increase in the abundance of 5' tRNA-halves among the total tDRs during hypoxia. Overall, our study provides a comprehensive characterization of the sncRNA profiles in HPH rats.

Multiple sclerosis (MS) is an inflammatory-mediated demyelinating disease of the central nervous system (CNS). Although studies have demonstrated that microglia facilitate remyelination in demyelinating diseases, the underlying mechanisms are still not fully characterized. We found that aryl hydrocarbon receptor (AhR), an environment sensor, was upregulated within the corpus callosum in the cuprizone model of CNS demyelination, and upregulated AhR was mainly confined to microglia. Deletion of AhR in adult microglia inhibited efficient remyelination. Transcriptome analysis using RNA-seq revealed that AhR-deficient microglia displayed impaired gene expression signatures associated with lysosome and phagocytotic pathways. Furthermore, AhR-deficient microglia showed impaired clearance of myelin debris and defected phagocytic capacity. Further investigation of target genes of AhR revealed that spleen tyrosine kinase (SYK) is the downstream effector of AhR and mediated the phagocytic capacity of microglia. Additionally, AhR deficiency in microglia aggravated CNS inflammation during demyelination. Altogether, our study highlights an essential role for AhR in microglial phagocytic function and suggests the therapeutic potential of AhR in demyelinating diseases.

Basic leucine zipper transcription factor ATF-like (BATF) -3 is a member of the activator protein 1 (AP‑1) family of transcription factors and is known to play a vital role in regulating differentiation of antigen-presenting cells in mammals. In this study, two BATF3 homologues (termed BATF3a and BATF3b) have been identified in rainbow trout (Oncorhynchus mykiss). Both genes were constitutively expressed in tissues, with particularly high levels of BATF3a in spleen, liver, pyloric caecae and head kidney. BATF3a was also more highly induced by PAMPs and cytokines in cultured cells, with type II IFN a particularly potent inducer. In rIL-4/13 pre-stimulated cells, the viral PAMPS polyI:C and R848 had the most pronounced effect on BATF3 expression. BATF3 expression could also be modulated in vivo, following infection with Yersinia ruckeri, a bacterial pathogen causing redmouth disease in salmonids, or with the rhabdovirus IHNV. The results suggest that BATF3 may be functionally conserved in regulating the differentiation and activation of immune cells in lower vertebrates and could be explored as a potential marker for comparative investigation of leucocyte lineage commitment across the vertebrate phyla.

Neuropeptide Y (NPY) is a 36 amino-acid amidated peptide of the pancreatic polypeptide (PP) family, which plays an important role in appetite regulation and energy expenditure in mammals. Although several teleost NPY have been identified, its roles remain unclear in fish. We herein reported on the molecular cloning, tissue distribution and the effect of fasting on the expression of NPY in Channa argus, and designated as CaNPY. It consisted of a 300 bp open reading frame predicted to encode a prepro-NPY of 99 amino acids. Sequence analysis revealed that CaNPY was highly conserved (>60%) with other vertebrate NPY. Phylogenetic analysis highly supported CaNPY was closely related to piscine NPY. In addition, except for muscle and spleen tissues, CaNPY was found to extensively expressed in all other detected tissues, with the highest level in brain. Futhermore, the CaNPY transcript was found to significantly increase after short-term and long-term food deprivation, and dramatically decrease following refeeding. These findings suggested that CaNPY might be involved in food intake regulation and it could be as a potential target locus to improve commercial production of this kind of fish.

The ability to efficiently generate integration-free induced pluripotent stem cells (iPSCs) from the most readily available source-peripheral blood-has the potential to expedite the advances of iPSC-based therapies. We have successfully generated integration-free iPSCs from cord blood (CB) CD34(+) cells with improved oriP/EBNA1-based episomal vectors (EV) using a strong spleen focus forming virus (SFFV) long terminal repeat (LTR) promoter. Here we show that Yamanaka factors (OCT4, SOX2, MYC, and KLF4)-expressing EV can also reprogram adult peripheral blood mononuclear cells (PBMNCs) into pluripotency, yet at a very low efficiency. We found that inclusion of BCL-XL increases the reprogramming efficiency by approximately 10-fold. Furthermore, culture of CD3(-)/CD19(-) cells or T/B cell-depleted MNCs for 4-6 days led to the generation of 20-30 iPSC colonies from 1 ml PB, an efficiency that is substantially higher than previously reported. PB iPSCs express pluripotency markers, form teratomas, and can be induced to differentiate in vitro into mesenchymal stem cells, cardiomyocytes, and hepatocytes. Used together, our optimized factor combination and reprogramming strategy lead to efficient generation of integration-free iPSCs from adult PB. This discovery has potential applications in iPSC banking, disease modeling and regenerative medicine.

Enhanced activity of interleukin 17 (IL-17) producing T helper 17 (Th17) cells plays an important role in autoimmune and inflammatory diseases. Significant loss of body weight and appetite is associated with chronic inflammation and immune activation, suggesting the cross talk between immune and neuroendocrine systems. Ghrelin has been shown to regulate the organism immune function. However, the effects of ghrelin on the differentiation of Th17 cells remain elusive. In the present study, we observed the enhanced differentiation of Th17 cells in spleens of growth hormone secretagogue receptor 1a (GHSR1a)-/- mice. Treatment of ghrelin repressed Th17 cell differentiation in a time- and concentration-dependent manner. Phosphorylation of mammalian target of rapamycin (mTOR) and signal transducer and activator of transcription 3 (STAT3) was increased in the spleens of GHSR1a-/- mice. Activation of mTOR signaling by injection of Cre-expressiong adenovirus into tuberous sclerosis complex 1 (TSC1) loxp/loxp mice increased the differentiation of Th17 cells in spleen, which was associated with an increment in the phosphorylation of STAT3. Activation of mTOR signaling by leucine or overexpression of p70 ribosome protein subunit 6 kinase 1 (S6K1) activated mTOR signaling in isolated T cells, while reversed the ghrelin-induced inhibition of iTh17 cell differentiation. In conclusion, mTOR mediates the inhibitory effect of ghrelin on the differentiation of Th17 cells by interacting with STAT3.

qPCR as a powerful and attractive methodology has been widely applied to aquaculture researches for gene expression analyses. However, the suitable reference selection is critical for normalizing target genes expression in qPCR. In the present study, six commonly used endogenous controls were selected as candidate reference genes to evaluate and analyze their expression levels, stabilities and normalization to immune-related gene IgM expression during vaccination and infection in spleen of tilapia with RefFinder and GeNorm programs. The results showed that all of these candidate reference genes exhibited transcriptional variations to some extent at different periods. Among them, EF1A was the most stable reference with RefFinder, followed by 18S rRNA, ACTB, UBCE, TUBA and GAPDH respectively and the optimal number of reference genes for IgM normalization under different experiment sets was two with GeNorm. Meanwhile, combination the Cq (quantification cycle) value and the recommended comprehensive ranking of reference genes, EF1A and ACTB, the two optimal reference genes, were used together as reference genes for accurate analysis of immune-related gene expression during vaccination and infection in Nile tilapia with qPCR. Moreover, the highest IgM expression level was at two weeks post-vaccination when normalized to EF1A, 18S rRNA, ACTB, and EF1A together with ACTB compared to one week post-vaccination before normalizing, which was also consistent with the IgM antibody titers detection by ELISA.

Respiratory immunization is an attractive way to generate systemic and mucosal protective memory responses that are required for preventing mucosally transmitted infections. However, the molecular and cellular mechanisms for controlling memory T cell responses remain incompletely understood. In this study, we investigated the role of respiratory macrophage (MΦ) in regulating CD4 T cell responses to recombinant adenovirus-based (rAd) vaccines. We demonstrated that rAd intranasal (i.n.) vaccination induced migration and accumulation of respiratory MΦ and circulatory monocytes in the mediastinal lymph nodes and lung parenchyma. Under the influence of respiratory MΦ CD4 T cells exhibited slow proliferation kinetics and an increased tendency of generating central memory, as opposed to effector memory, CD4 T cell responses in vitro and in vivo. Correspondingly, depletion of MΦ using clodronate-containing liposome prior to i.n. immunization significantly enhanced CD4 T cell proliferation and increased the frequency of CD4 memory T cells in the airway lumen, demonstrating that MΦ initially serve as a negative regulator in limiting generation of mucosal tissue-resident memory CD4 T cells. However, clodronate-containing liposome delivery following i.n. immunization markedly reduced the frequencies of memory CD4 T cells in the airway lumen and spleen, indicating that respiratory MΦ and potentially circulating monocytes are critically required for maintaining long-term memory CD4 T cells. Collectively, our data demonstrate that rAd-induced mucosal CD4 T memory responses are regulated by respiratory MΦ and/or monocytes at multiple stages.