Dendritic cell migration in health and disease

Lysine vitcylation is a vitamin C-derived protein modification that enhances STAT1-mediated immune response

Vitamin C (vitC) is essential for health and shows promise in treating diseases like cancer, yet its mechanisms remain elusive. Here, we report that vitC directly modifies lysine residues to form "vitcyl-lysine"-a process termed vitcylation. Vitcylation occurs in a dose-, pH-, and sequence-dependent manner in both cell-free systems and living cells. Mechanistically, vitC vitcylates signal transducer and activator of transcription-1 (STAT1)- lysine-298 (K298), impairing its interaction with T cell protein-tyrosine phosphatase (TCPTP) and preventing STAT1-Y701 dephosphorylation. This leads to enhanced STAT1-mediated interferon (IFN) signaling in tumor cells, increased major histocompatibility complex (MHC)/human leukocyte antigen (HLA) class I expression, and activation of anti-tumor immunity in vitro and in vivo. The discovery of vitcylation as a distinctive post-translational modification provides significant insights into vitC's cellular function and therapeutic potential, opening avenues for understanding its biological effects and applications in disease treatment.

Adoptively transferred tumor-specific IL-9-producing cytotoxic CD8+ T cells activate host CD4+ T cells to control tumors with antigen loss

Host effector CD4+ T cells emerge as critical mediators for tumor regression but whether they can be activated by adoptively transferred CD8+ T cells remains unknown. We previously reported that adoptive transfer of interleukin 9 (IL-9)-producing cytotoxic CD8+ T (Tc9) cells achieved long-term control of tumor growth. Here, we demonstrate that murine tumor-specific Tc9 cells control the outgrowth of antigen-loss relapsed tumors by recruiting and activating host effector CD4+ T cells. Tc9 cells secreted IL-24 and recruited CCR7-expressing conventional type 2 dendritic cells (cDC2 cells) into tumor-draining lymph nodes to prime host CD4+ T cells against relapsed tumors. Host CD4+ T cell or cDC2 deficiency impaired the ability of Tc9 cells to control relapsed tumor outgrowth. Additionally, intratumoral IL24 expression correlates with cDC2 and CD4+ T cell gene signatures in human cancers and their expression is associated with better patient survival. This study reports a mechanism for activation of tumor-specific CD4+ T cells in vivo.

Identification of novel IL17-related genes as prognostic and therapeutic biomarkers of psoriasis using comprehensive bioinformatics analysis and machine learning

Psoriasis is a common chronic skin disorder with a polygenic background. It is widely acknowledged that Th17/IL-17A axis plays a key role in the pathogenesis of psoriasis. However, numerous regulatory genes upstream of the pathway remain undiscovered, creating a knowledge gap in our understanding of the genetic aspects of the Th17/IL-17A axis. In this study, we employed machine learning algorithms to identify three target genes associated with psoriasis: CCR7, IL2RG, and PLEK. The validation of these genes was carried out in specimens from psoriatic patients. In vivo, investigations assessed the relationship between these three genes and IL-17A-related inflammation and their connection to psoriatic phenotypes. To further confirm the significance of the newly discovered gene, PLEK, we performed experiments involving the blockade of its expression. Our bioinformatics analysis revealed three novel genes closely linked to psoriasis: CCR7, IL2RG, and PLEK. These genes exhibited upregulated expression in psoriasis, consistently aligning with the Th17/IL-17A axis. Inhibition of PLEK expression reduced Th17/IL-17A-related inflammation and alleviated psoriatic phenotypes. CCR7, IL2RG, and PLEK show potential as three novel biomarkers for psoriasis, with PLEK being reported for the first time in this context. These genes contribute to pathogenesis by associating with the Th17/IL-17A signaling pathway.

The Direct and Indirect Role of IgE on Airway Epithelium in Asthma

Asthma is a chronic airway inflammatory disorder, affecting over 350 million people worldwide, with allergic asthma being the most common form of the disease. Allergic asthma is characterized by a type 2 (T2) inflammatory response triggered by numerous allergens beginning in the airway epithelium, which acts as a physical barrier to allergens as well as other external irritants including infectious agents, and atmospheric pollutants. T2 inflammation is propagated by several key cell types including T helper 2 (Th2) cells, eosinophils, mast cells, and B cells. Immunoglobulin E (IgE), produced by B cells, is a key molecule in allergic airway disease and plays an important role in T2 inflammation, as well as being central to remodeling processes within the airway epithelium. Blocking IgE with omalizumab has been shown to be efficacious in treating allergic asthma however, the role of IgE on airway epithelial cells is less communicated. Developing a deeper explanation of the complex network of interactions between IgE and the airway epithelium will facilitate an improved understanding of asthma pathophysiology. This review discusses the indirect and direct roles of IgE on airway epithelial cells, with a focus on allergic asthma disease.

USP14 inhibits sensitization-mediated degradation of KDM4D to epigenetically regulate dendritic cell tolerogenic capacity and mitigates airway allergy

Numerous immune disorders are caused by the dysfunction of dendritic cells (DC). The mechanism has not been fully comprehended yet. This research is designed to regulate the epigenetic status of lysine-specific demethylase 4D (KDM4D) to enhance DC's immune tolerogenic capacity. In this study, an airway allergy (AA) mouse model was established with dust mite extracts (DME) as the specific antigen. A mouse strain carrying Kdm4d-deficient DCs was employed in the experiments to assess the role of KDM4D in modulating DC's immune tolerogenic functions. The results showed that mice carrying Kdm4d-deficient DCs (KO mice) showed spontaneous Th2 polarization in the airways. Reduced quantities of KDM4D were detected in airway naive DCs (nDCs) of AA mice. The parameters of AA response had a negative correlation with the quantity of KDM4D. The immune tolerogenic capacity of airway nDCs was impaired in KO mice as well as in AA mice. The Il10 promoter was found to be hypermethylated in airway nDCs of AA mice and KO mice. The low quantity of deubiquitinating enzyme 14 (USP14) was related to the high level of hyper ubiquitination observed in KDM4D in the Il10 promoter locus of airway nDCs of AA mice. Exposure to recombinant USP14 increased the quantity of KDM4D in nDCs, restoring the immune tolerogenic capacity of nDCs in AA mice. In conclusion, dysfunctional tolerogenicity is caused by low levels of KDM4D in airway nDCs from AA mice. USP14 restores the tolerogenic capacity of nDCs in AA mice and mitigates experimental AA.

Hydrotalcites-Induced Pyroptosis Combined with Toll-Like Receptor Activation Elicited Dual Stimulation of Innate and Adaptive Immunity

Increasing evidence illustrates the significance of promoting tumor immunogenicity and an efficient immune response in immunotherapy, but the immunosuppressive tumor microenvironment (TME) remains an obstacle. Herein, AlZn hydrotalcite (AZOH) was synthesized as a pyroptosis inducer and further loaded with R848 to formulate R@AZOH. R@AZOH efficiently triggered CT26 cell pyroptosis through Zn2+ overload-evoked mitochondrial dysfunction and its downstream caspase-1/GSDMD pathway, resulting in the release of inflammatory cytokines, membrane fracture, and immunogenic cell death (ICD). Moreover, R@AZOH served as antigen traps to facilitate antigen presentation, thereby cooperating with TLR activation to dually stimulate dendritic cells (DCs). The combination of R@AZOH rapidly initiated innate immunity and prolonged the adaptive immune response, resulting in the suppression of tumor growth, immune cell activation and a "hot" tumor niche. The potent antitumor immunity was further enhanced by combination with an immune checkpoint inhibitor (αCTLA-4), which inhibited both primary and distant tumors, as well as systemic immune activation. Astonishingly, we also explored the potential application of R@AZOH as a tumor vaccine adjuvant and demonstrated its ability to elicit immunological memory to prevent tumor growth in an orthotopic melanoma model. Overall, our work emphasized the potential application of combining pyroptosis and TLR activation to stimulate both innate and adaptive immunity to overcome the immunosuppressive TME and presented a good adjuvant candidate.

Cryo-Shocked Tumor-Reprogrammed Sonosensitive Antigen-Presenting Cells Improving Sonoimmunotherapy via T Cells and NK Cells Immunity

Ultrasound therapy has turned up as a noninvasive multifunctional tool for cancer immunotherapy. However, the insufficient co-stimulating molecules and loss of peptide-major histocompatibility complex I (MHC-I) expression on tumor cells lead to poor therapy of sonoimmunotherapies. Herein, this work develops a sonosensitive system to augment MHC-I unrestricted natural killer (NK) cell-mediated innate immunity and T cell-mediated adaptive immunity by leveraging antigen presentation cell (APC)-like tumor cells. Genetically engineered tumor cells featuring sufficient co-stimulating molecules are cryo-shocked and conjugated with a sonosensitizer, hematoporphyrin monomethyl ether, using click chemistry. These cells (DPNLs) exhibit characteristics of tumor and draining lymph node homing. Under ultrasound, NK cell-mediated innate immunity within the tumor microenvironment could be activated, and T cells in the tumor-draining lymph nodes (TDLNs) are stimulated through co-stimulatory molecules. In combination with programmed cell death ligand 1 (PD-L1) antibody, DPNLs extend the survival time and inhibited lung metastasis in triple-negative breast cancer (TNBC) models. This study provides an alternative approach for sonoimmunotherapy with precise sonosensitizer delivery and enhanced NK cell and T cell activation.

Beyond CCR7: dendritic cell migration in type 2 inflammation

Conventional dendritic cells (cDCs) are crucial antigen-presenting cells that initiate and regulate T cell responses, thereby shaping immunity against pathogens, innocuous antigens, tumors, and self-antigens. The migration of cDCs from peripheral tissues to draining lymph nodes (dLNs) is essential for their function in immune surveillance. This migration allows cDCs to convey the conditions of peripheral tissues to antigen-specific T cells in the dLNs, facilitating effective immune responses. Migration is primarily mediated by chemokine receptor CCR7, which is upregulated in response to homeostatic and inflammatory cues, guiding cDCs to dLNs. However, during type 2 immune responses, such as those triggered by parasites or allergens, a paradox arises-cDCs exhibit robust migration to dLNs despite low CCR7 expression. This review discusses how type 2 inflammation relies on additional signaling pathways, including those induced by membrane-derived bioactive lipid mediators like eicosanoids, sphingolipids, and oxysterols, which cooperate with CCR7 to enhance cDC migration and T helper 2 (Th2) differentiation. We explore the potential regulatory mechanisms of cDC migration in type 2 immunity, offering insights into the differential control of cDC trafficking in diverse immune contexts and its impact on immune responses.

Biodegradable Electrospun PLGA Nanofibers-Encapsulated Trichinella Spiralis Antigens Protect from Relapsing Experimental Autoimmune Encephalomyelitis and Related Gut Microbiota Dysbiosis

Purpose

Trichinella spiralis has evolved complex immunomodulatory mechanisms mediated by excretory-secretory products (ESL1) that enable its survival in the host. Consequently, ESL1 antigens display excellent potential for treating autoimmune diseases such as multiple sclerosis (MS). However, whether timely controlled delivery of ESL1 antigens in vivo, as in natural infections, could enhance its therapeutic potential for MS is still unknown.

Methods

To test this, we encapsulated ESL1 antigens into biodegradable poly (lactide-co-glycolic) acid (PLGA) nanofibers by emulsion electrospinning as a delivery system and assessed their release dynamics in vitro, and in an animal MS model, experimental autoimmune encephalomyelitis (EAE), induced 7 days after PLGA/ESL1 subcutaneous implantation. PLGA/ESL1 effects on EAE symptoms were monitored along with multiple immune cell subsets in target organs at the peak and recovery of EAE. Gut barrier function and microbiota composition were analyzed using qPCR, 16S rRNA sequencing, and metabolomic analyses.

Results

ESL1 antigens, released from PLGA and drained via myeloid antigen-presenting cells through lymph nodes, protected the animals from developing EAE symptoms. These effects correlated with reduced activation of myeloid cells, increased IL-10 expression, and reduced accumulation of proinflammatory natural killer (NK) cells, T helper (Th)1 and Th17 cells in the spleen and central nervous system (CNS). Additionally, CD4+CD25hiFoxP3+ regulatory T cells and IL-10-producing B cells were expanded in PLGA/ESL1-treated animals, compared to control animals. The migration of ESL1 to the guts correlated with locally reduced inflammation and gut barrier damage. Additionally, PLGA/ESL1-treated animals displayed an unaltered microbiota characterized only by a more pronounced protective mevalonate pathway and expanded short-chain fatty acid-producing bacteria, which are known to suppress inflammation.

Conclusion

The delivery of T. spiralis ESL1 antigens via biodegradable electrospun PLGA nanofiber implants efficiently protected the animals from developing EAE by inducing a beneficial immune response in the spleen, gut, and CNS. This platform provides excellent grounds for further development of novel MS therapies.

AlbiCDN: albumin-binding amphiphilic STING agonists augment the immune activity for cancer immunotherapy

The stimulator of interferon genes (STING) has been an attractive target in cancer immunotherapy. However, natural ligand cyclic dinucleotides (CDNs) and CDN derivatives have demonstrated limited efficacy in clinical trials. This limitation stems from the inherent structure of CDNs, which leads to enzymatic degradation, poor cell internalisation, rapid clearance from the tumour microenvironment, and dose-limiting toxicity. In this study, we developed an amphipathic STING agonist, termed albumin-binding CDNs (AlbiCDNs), to enhance the efficacy of c-di-GMP (CDG) via a lipid-conjugated strategy. The lipid provided a platform for albumin hitchhiking, which facilitated the cytoplasmic delivery of CDG without the use of any exogenous components. In addition, incorporating a stimuli-responsive lipid motif further enhanced the cellular release of CDG. Our results indicated that CDG-1C14, an AlbiCDN, efficiently stimulated the maturation and activation of antigen-presenting cells through STING activation. Furthermore, CDG-1C14 exhibited a significant inhibitory effect on the tumour therapeutic model. Therefore, AlbiCDN is a potent platform for cancer immunotherapy that can expedite clinical translation.

FcγRI plays a pro-inflammatory role in the immune response to Chlamydia respiratory infection by upregulating dendritic cell-related genes

BACKGROUND

FcγRI, a pivotal cell surface receptor, is implicated in diverse immune responses and is ubiquitously expressed on numerous immune cells. However, its role in intracellular bacterial infections remains understudied.

METHODS

Wild-type (WT) and FcγRI knockout (FcγRI-KO) mice were inoculated intranasally with a specific dose of C. muridarum. Lung tissues were harvested for transcriptome sequencing, and flow cytometry was employed to validate bioinformatics immune infiltration analysis. Differentially expressed DC-associated genes were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses to elucidate their functions during infection. A PPI network was constructed to pinpoint crucial genes, and qPCR was utilized to confirm their expression changes. Additionally, we compared body weight, lung Chlamydia load, and pathological alterations between WT and FcγRI-KO mice post-infection to assess the effect of FcγRI on inflammation via gene regulation. Lastly, an mRNA-miRNA-lncRNA network was formulated to further probe the molecular mechanisms of FcγRI in C. muridarum infection.

RESULTS

Post-C. muridarum infection, FcγRI-KO mice exhibited a notable decrease in DC infiltration and maturation, along with downregulated co-stimulatory molecules (CD40, CD80, CD86) in lung tissues. Differential gene analysis identified 26 differentially expressed DC-related genes implicated in DC proliferation, migration, and inflammatory responses. KEGG analysis revealed their close association with key immune pathways. The PPI network delineated two modules, with the top six genes in the pivotal cluster 1 (Ccl4, Il6, Ccl3, Ptgs2, Il 1α, Il7) being significantly downregulated in FcγRI-KO mice. A ceRNA network encompassing 12 miRNAs and 37 lncRNAs regulating four key genes (Ptgs2, Il1α, Il6, Il7) was also constructed.

CONCLUSIONS

In C. muridarum respiratory infections, FcγRI facilitates DC infiltration and maturation, upregulates six pro-inflammatory genes (Ccl4, Il6, Ccl3, Ptgs2, Il1α, Il7), and exhibits a pro-inflammatory role. A key ceRNA network was formulated to unravel the underlying molecular mechanisms.

Dendritic cells immunotargeted therapy for atherosclerosis

Atherosclerosis, a chronic inflammatory disease, is markedly influenced by both immune and inflammatory reactions throughout its progression. Dendritic cells, as pivotal antigen-presenting entities, play a crucial role in the initiation of immune responses and the preservation of immunological homeostasis. Accumulating data indicates that dendritic cells are present in healthy arteries and accumulate significantly in atherosclerotic plaques. Novel immunotherapeutic approaches and vaccination protocols have yielded substantial clinical advancements in managing chronic inflammatory diseases, with dendritic cell-centric modalities emerging for atherosclerotic management. In this review, we delineate the essential functions and underlying mechanisms of dendritic cells and their subsets in the modulation of atherosclerotic inflammation and immune responses. We underscore the immense promise of dendritic cell-based immunotherapeutic strategies, including vaccines and innovative combinations with nanotechnological drug delivery platforms for atherosclerosis treatment. We also discuss the challenges associated with dendritic cell immunotherapy and provide perspectives on the future direction of this field.

Development and validation of a prognostic and drug sensitivity model for gastric cancer utilizing telomere-related genes

BACKGROUND

Gastric cancer (GC) poses a major global health challenge because of its unfavorable prognosis. Elevated telomerase activity has been linked to the rapid growth and invasiveness of GC tumors. Investigating the expression profiles of telomerase could improve our understanding of the mechanisms underlying telomere-related GC advancement and its applicability as potential targets for diverse therapeutic strategies for GC.

METHODS

The TCGA and GEO databases were utilized to access transcriptome and clinical data related to GC. After assessing differentially expressed genes (DEGs), a prognostic risk model was developed through Cox univariate regression, LASSO-Cox regression. The prognostic risk model was validated using data from the GSE62254 cohort. The significant influence of the risk model on the tumor immune microenvironment (TIME) and its sensitivity to various drugs was assessed.

RESULTS

Differential expression analysis identified 328 significantly telomere-related DEGs in GC, with 35 of them showing a significant association with GC prognosis. A predictive risk model composed of four telomere-related genes (TRGs) was established, enabling the accurate stratification of GC patients into two distinct prognostic groups. The LASSO risk model demonstrated notable variations in immune-cell infiltration and drug sensitivity patterns between high- and low-risk groups.

CONCLUSIONS

The study establishes suggestive relationships between four TRGs (LRRN1, SNCG, GAMT, and PDE1B) and the prognosis of GC. The comprehensive characterization of the TRG model reveals their possible roles in the prognosis, TIME, and drug sensitivity in GC.

IL-33 released during challenge phase regulates allergic asthma in an age-dependent way

Epithelial-derived cytokines, especially type 2 alarmins (TSLP, IL-25, and IL-33), have emerged as critical mediators of type 2 inflammation. IL-33 attracts more interest for its strong association with allergic asthma, especially in childhood asthma. However, the age-dependent role of IL-33 to the development of allergic asthma remains elusive. Here, using OVA-induced allergic asthma model in neonatal and adult mice, we report that IL-33 is the most important alarmin in neonatal lung both at steady state or inflammation. The deficiency of IL-33/ST2 abrogated the development of allergic asthma only in neonates, whereas in adults the effect was limited. Interestingly, the deficiency of IL-33/ST2 equally dampened the ILC2 responses in both neonatal and adult models. However, the effect of IL-33/ST2 deficiency on Th2 responses is age-dependent, which is only blocked in neonates. Furthermore, IL-33/ST2 signaling is dispensable for OVA sensitization. Following OVA challenge in adults, the deficiency of IL-33/ST2 results in compensational more TSLP, which in turn recruits and activates lung DCs and boosts Th2 responses. The enriched γδ T17 cells in IL-33/ST2 deficient neonatal lung suppress the expression of type 2 alarmins, CCL20 and GM-CSF via IL-17A, thus might confer the inhibition of allergic asthma. Finally, on the basis of IL-33 deficiency, the additive protective effects of TSLP blocking is much more pronounced than IL-25 blocking in adults. Our studies demonstrate that the role of IL-33 for ILC2 and Th2 responses varies among ages in OVA models and indicate that the factor of age should be considered for intervention of asthma.

PD-L1-CD80 interactions are required for intracellular signaling necessary for dendritic cell migration

Programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) interactions are targets for immunotherapies aimed to reinvigorate T cell function. Recently, it was documented that PD-L1 regulates dendritic cell (DC) migration through intracellular signaling events. In this study, we find that both preclinical murine and clinically available human PD-L1 antibodies limit DC migration. We show that cis interactions between PD-L1 and CD80 are critical for promoting migration and define specific regions within these proteins necessary for migration. Furthermore, we demonstrate that αPD-L1 significantly impedes DC migration in a B16 melanoma tumor model. Last, we outline how blocking cis PD-L1:CD80 interactions or mutation of the intracellular domain of PD-L1, in an imiquimod-induced murine model of psoriasis, limits DC migration to the lymph node, decreases interleukin-17 production by CD4+ T cells in the lymph node, and reduces epidermal thickening. Therefore, PD-L1 and CD80 interactions are important regulators of DC migration to the draining lymph node.

Concentration-dependent effects of immunomodulatory cocktails on the generation of leukemia-derived dendritic cells, DCleu mediated T-cell activation and on-target/off-tumor toxicity

Acute myeloid leukemia (AML) remains a devastating diagnosis in clear need of therapeutic advances. Both targeted dendritic cells (DC) and particularly leukemia-derived dendritic cells (DCleu) can exert potent anti-leukemic activity. By converting AML blasts into immune activating and leukemia-antigen presenting cells, DC/DCleu-generating protocols can induce immune responses against AML blasts. Such protocols combine approved response modifiers (i.e., GM-CSF and PGE1/OK-432/PGE2) that synergistically improve the conversion of AML blasts into (mature) DC/DCleu. To guide potential clinical application of these response modifiers, we analyzed three different DC-generating protocols that combine a constant GM-CSF dose with varying concentrations of PGE1 (Kit-M), OK-432 (Kit-I), and PGE2 (Kit-K). Here, we specifically aimed to assess how different response modifier concentrations impact DC/DCleu generation, immune cell activation and leukemic blast lysis. We found that all immunomodulatory kits were effective in generating mature and leukemia-derived DCs from healthy and leukemic whole blood. For Kit-M, we noted optimal generation of DC-subsets at intermediary concentration ranges of PGE1 (0.25-4.0 µg/mL), which facilitated upregulation of activated and memory T-cells upon mixed lymphocyte culture, and efficient anti-leukemic activity in cytotoxicity assays. For Kit-I, we observed DC/DCleu generation and enhanced T- and immune cell activation across a broader range of OK-432 concentrations (5-40 µg/mL), which also facilitated improved leukemic blast killing. In conclusion, our results highlight that Kit-mediated DC/DCleu generation, immune cell activation and blast lysis are dependent on the concentration of response modifiers, which will guide future clinical development. Overall, DCleu-based immunotherapy represents a promising treatment strategy for AML patients.

Bacterial vaginosis is associated with transcriptomic changes but not higher concentrations of cervical leukocytes in a study of women at high risk for HIV acquisition

BACKGROUND

The association between bacterial vaginosis (BV) and increased HIV acquisition risk may be related to concentrations of HIV-susceptible immune cells in the cervix.

METHODS

Participants (31 with BV and 30 with normal microbiota) underwent cervical biopsy at a single visit. Immune cells were quantified and sorted using flow cytometry (N=55), localization assessed by immunofluorescence (N=16), and function determined by bulk RNA sequencing (RNA-seq) of live CD45+ cells (N=21).

RESULTS

Linear regression analyses demonstrated no differences in mean log2 [cells/mg tissue] between women with BV vs normal microbiota for antigen presenting cell (APC) subtypes linked to HIV risk (including CD1a+HLA-DR+ Langerhans cells, CD11c+CD14+ dendritic cells [DCs], and CD11c+HLA-DR+ DCs) and CD4+ T cells. Women with BV had a higher median proportion of CD11c+HLA-DR+ APCs (out of total cells) in cervical epithelium (0.1% vs 0.0%; p=0.03 using Mann-Whitney testing). RNA-seq identified 1,032 differentially expressed genes (adjusted p-value <0.05) in CD45+ cells between women with BV vs normal microbiota. Women with BV demonstrated downregulation of pathways linked to translation, metabolism, cell stress, and immune signaling.

CONCLUSIONS

BV alters immune cell localization and function; future studies are needed to address how these changes may mediate HIV acquisition risk.

Unleashing the role of potential adjuvants in leishmaniasis

Leishmaniasis is amongst one of the most neglected tropical disease, caused by an intracellular protozoan of genus Leishmania. Currently, the most promising strategy to combat leishmaniasis, relies on chemotherapy but the toxicity and increasing resistance of the standard drugs, presses the demand for new alternatives. Immunization is arguably the best strategy for cure because an individual once infected becomes immune to the disease. Yet, there is no efficient vaccine capable of providing enduring immunity against the parasite. Achieving the goal of developing highly efficacious and durable vaccine is limited due to lack of an appropriate adjuvant. Adjuvants are recognized as 'immune potentiators' which redirect or amplify the immune response. A number of adjuvants like alum, MPL-A, CpG ODN, GLA-SE, imiquimod, saponins etc. have been used in combination with various classes of Leishmania antigens. However, only few have reached clinical trials. Thus, the choice of an adjuvant is critically dependent on many factors such as the route of administration, the nature of antigen, formulation, the type of required immune response, their mode of action and the immunization schedule. This review provides an updated status on the types of adjuvants used in leishmaniasis so far and their mechanism of action if known.

Low molecular weight fucoidan induces M2 macrophage polarization to attenuate inflammation through activation of the AMPK/mTOR autophagy pathway

Fucoidan, a sulfated polysaccharide with a complex structure, has gradually become the focus of biomedical research due to its remarkable biological activity and low toxicity. In this research, it was noted that low molecular weight fucoidan (LMWF) exhibited significant antimicrobial effects on Methicillin-resistant Staphylococcus aureus (MRSA) and promoted polarization towards M2 macrophages, leading to a substantial reduction in inflammatory responses within the lipopolysaccharide (LPS)-activated macrophages. We further explored the mechanism underlying the anti-inflammation activity. Our findings indicated that LMWF significantly enhanced the phosphorylation level of AMP-activated protein kinase (AMPK), inhibited the phosphorylation of the mammalian target of rapamycin (mTOR), and enhanced the expression of LC3II. Meanwhile, Compound C (CC) substantially reversed the anti-inflammation effect of LMWF, indicating that the AMPK pathway plays a pivotal role in this effect. In in vivo research, LMWF revealed impressive anti-inflammatory potential. LMWF treatment significantly eliminated MRSA and ameliorated inflammatory symptoms in mice's MRSA-infected skin wound model. Further analysis using Western Blot (WB) indicated significant AMPK/mTOR signaling pathway activation in mice treated with LMWF, which led to accelerated polarization of macrophages from the M1 to the M2 phenotype. In summary, we systematically explored the mechanism by which LMWF exerts anti-inflammatory effects through in vitro and in vivo experiments. It was confirmed that LMWF effectively induced the conversion of macrophages to an anti-inflammatory M2 phenotype by activating the AMPK/mTOR pathway. Simultaneously, LMWF effectively eradicated MRSA and accelerated wound healing in mice. This finding provides an important theoretical basis for further research on fucoidan.

Amelioration of experimental autoimmune encephalomyelitis by exogenous soluble PD-L1 is associated with restraining dendritic cell maturation and CCR7-mediated migration

Dendritic cells (DCs) orchestrate both immune activation and immune tolerance in multiple sclerosis (MS). Manipulating the phenotypes and functions of DCs to boost their tolerogenic potential is an appealing strategy for treating MS and its animal model experimental autoimmune encephalomyelitis (EAE). Programmed cell death 1 (PD-1) delivers the immunoinhibitory signals by interacting with PD-1 ligand 1 (PD-L1), which plays a critical role in maintaining immune tolerance. So far, the effects of PD-1/PD-L1 signalling activation on DCs in EAE are poorly understood. Here, the administration of soluble PD-L1 (sPD-L1) protein significantly alleviated the clinical symptoms of myelin oligodendrocyte glycoprotein (MOG)-induced EAE, and inhibited the expression of cluster of differentiation (CD)86, C-C motif chemokine receptor 7 (CCR7) as well as CCR7-mediated trafficking of splenic DCs, accompanied by enhancing their phagocytosis. The impact of sPD-L1 on the surface morphology and mechanical properties of DCs was investigated at the nanoscale, using scanning electron microscope and atomic force microscope. The treatment of sPD-L1 was found to mitigate morphological maturation and biomechanical alterations, specifically in terms of adhesion and elasticity, in bone marrow-derived DCs from EAE. Taken together, our findings suggest that application of exogenous sPD-L1 has a marked suppressive effect on the maturation and migration of DCs in EAE. PD-L1 administration may be a promising therapy for EAE and for MS in the future.

Dust mite antigens endow dendritic cells with the capacity to induce a Th2 response by regulating their methylation profiles

BACKGROUND

It is well-known that Dendritic cells (DCs) are essential in the development of airway Th2 polarization and airway allergy (AA). The underlying mechanism is still not fully understood. The objective of this study is to examine the role of methyltransferase-like protein-5 (Mettl5), a methyltransferase involved in N6-methyladenosine (m6A) methylation, in altering DC's properties to facilitate the development of Th2 polarization and AA.

METHODS

Dust mite extracts (DME) were used as a specific antigen to establish an AA mouse model. The epigenetic status of DCs was examined using a Chromatin immunoprecipitation (ChIP) assay. A mouse strain carrying the Mettl5-deficient DCs was used to observe the role of Mettl5 in determining the phenotypes of DCs.

RESULTS

The results showed that the expression of Mettl5 was elevated in DCs, which was positively correlated with the AA response. The development of airway Th2 polarization was hindered by Mettl5 depletion in DCs. Mettl5 is involved in the transcription of the Timd4 gene in DCs caused by DME. The degradation of IRF5 by Mettl5 led to an increase in T cell immunoglobulin domain molecule-4 (TIM4) expression in DCs associated with DME. Inhibition of Mettl5 in DCs reconciled the DME-induced airway Th2 polarization and experimental AA.

CONCLUSIONS

Airway DCs from AA mice showed elevated amounts of Mettl5, which led to the expression of TIM4. The experimental AA was mitigated by Mettl5 inhibition.

The physiological landscape and specificity of antibody repertoires are consolidated by multiple immunizations

Diverse antibody repertoires spanning multiple lymphoid organs (i.e., bone marrow, spleen, lymph nodes) form the foundation of protective humoral immunity. Changes in their composition across lymphoid organs are a consequence of B-cell selection and migration events leading to a highly dynamic and unique physiological landscape of antibody repertoires upon antigenic challenge (e.g., vaccination). However, to what extent B cells encoding identical or similar antibody sequences (clones) are distributed across multiple lymphoid organs and how this is shaped by the strength of a humoral response remains largely unexplored. Here, we performed an in-depth systems analysis of antibody repertoires across multiple distinct lymphoid organs of immunized mice and discovered that organ-specific antibody repertoire features (i.e., germline V-gene usage and clonal expansion profiles) equilibrated upon a strong humoral response (multiple immunizations and high serum titers). This resulted in a surprisingly high degree of repertoire consolidation, characterized by highly connected and overlapping B-cell clones across multiple lymphoid organs. Finally, we revealed distinct physiological axes indicating clonal migrations and showed that antibody repertoire consolidation directly correlated with antigen specificity. Our study uncovered how a strong humoral response resulted in a more uniform but redundant physiological landscape of antibody repertoires, indicating that increases in antibody serum titers were a result of synergistic contributions from antigen-specific B-cell clones distributed across multiple lymphoid organs. Our findings provide valuable insights for the assessment and design of vaccine strategies.

Altered Immune Cell Profiles in the Follicular Fluid of Patients with Poor Ovarian Response According to the POSEIDON Criteria

Objective

This study aims to investigate alterations in immune cell counts within preovulatory follicles of patients with poor ovarian response (POR) during assisted reproductive technology (ART), classified according to the POSEIDON criteria.

Methods

This single-centre cross-sectional study included 543 women undergoing IVF/ICSI treatment, selected based on specific inclusion and exclusion criteria: 292 with normal ovarian response and 251 with poor response. Follicular fluid (FF) was collected on the day of oocyte retrieval and analysed by flow cytometry to determine the proportions of macrophages (Mφs), M1 and M2 Mφs, T cells (CD4 and CD8 T cells), dendritic cells (DCs), including type 1 conventional dendritic cells (cDC1) and type 2 conventional dendritic cells (cDC2), and neutrophils. Multivariable logistic regression assessed the relationship between immune cell counts and POR, Pearson correlation determined associations with the number of retrieved oocytes, and receiver operating characteristic (ROC) curves evaluated the predictive power of immune cell counts for POR.

Results

Immune cells accounted for 52.57% (±23.90%) of the total cell population in the follicular microenvironment, which was approximately equal to that of granulosa cells, with Mφs being the most abundant, followed sequentially by T cells, DCs, and neutrophils. In patients with POR, overall Mφs infiltration in the follicular microenvironment decreased, whereas M1 and M2 polarization increased. T cell infiltration increased, with a decrease in the CD4/CD8 ratio. Both cDC1 and cDC2 were significantly elevated. Moreover, multivariable logistic regression revealed that the total macrophage count, CD4 T cell count, and cDC2 count were independent predictors of POR. Notably, cDC2 showed the largest area under the ROC curve, suggesting its strong potential as a biomarker for predicting POR.

Conclusion

The proportion of immune cells in preovulatory follicles were significantly altered in patients with POR. These findings suggest that immune cell dynamics in the follicular microenvironment may play a crucial role in determining ovarian response and prognosis, indicating that targeted immunomodulatory strategies could be considered in future therapeutic approaches.

Bothrops atrox snake venom decreased MHC-II and CD86 expression in bone marrow-derived dendritic cells

The effect of Bothrops atrox venom (BaV) on the maturation of bone marrow-derived dendritic cells (BMDCs) from mice was investigated, with a focus on selected cell markers, TAP1 expression, and the release of pro-inflammatory cytokines during this process. The objective was to evaluate BaV's impact on dendritic cell (DC) function, as DCs are pivotal in antigen presentation and responsible for initiating the immune response mediated by naïve T cells, as well as regulating the immune system. Bone marrow cells were obtained from Swiss mice, and hematopoietic precursors were differentiated into BMDCs using GM-CSF and IL-4. On the 7th day, BaV and LPS were introduced into the culture, and the cells were analyzed 24 h later. BaV's ability to stimulate BMDC maturation was assessed through the analysis of surface marker expression. The findings demonstrated that BMDCs are highly influenced by culture environment factors, such as GM-CSF and IL-4, and are sensitive to additional stimuli like LPS and BaV. Mature DCs exhibited elevated levels of critical markers for T cell activation, such as MHC-II, CD80, and CD86, displaying specific phenotypic characteristics. However, the observed reduction in MHC-II and CD86 expression following BaV exposure suggests a substantial impact on the immunological activation capacity of these cells, potentially interfering with the adaptive immune response. Furthermore, the selective release of cytokines, such as IL-6, but not TNF-α or IL-1β, indicates differentiated modulation of inflammatory responses by DCs under various stimulation conditions.

Cytological changes in radiation-induced lung injury

Radiation-induced lung injury (RILI) is a prevalent complication associated with radiotherapy for thoracic tumors. Based on the pathological progression, it can be categorized into two stages: early radiation pneumonitis and late radiation pulmonary fibrosis. The occurrence of RILI not only constrains the therapeutic dose that can be administered to the tumor target area but also significantly impairs patients' health and quality of life, thereby limiting the efficacy and applicability of radiotherapy. To effectively prevent and mitigate the development of RILI, it is crucial to disclose its underlying mechanisms. This review aims to elucidate the specific mechanisms involved in RILI and to examine the roles of various cell types, including lung parenchymal cells and different immune cells. The functions and interactions of lung epithelial cells, pulmonary vascular endothelial cells, a variety of immune cells, and fibroblasts during different stages of inflammation, tissue repair, and fibrosis following radiation-induced lung injury are analyzed. A comprehensive understanding of the dynamic changes in these cellular components is anticipated to offer new strategies for the prevention of RILI.

Triggering immunogenic death of cancer cells by nanoparticles overcomes immunotherapy resistance

Immunotherapy resistance poses a significant challenge in oncology, necessitating novel strategies to enhance the therapeutic efficacy. Immunogenic cell death (ICD), including necroptosis, pyroptosis and ferroptosis, triggers the release of tumor-associated antigens and numerous bioactive molecules. This release can potentiate a host immune response, thereby overcoming resistance to immunotherapy. Nanoparticles (NPs) with their biocompatible and immunomodulatory properties, are emerging as promising vehicles for the delivery of ICD-inducing agents and immune-stimulatory adjuvants to enhance immune cells tumoral infiltration and augment immunotherapy efficacy. This review explores the mechanisms underlying immunotherapy resistance, and offers an in-depth examination of ICD, including its principles and diverse modalities of cell death that contribute to it. We also provide a thorough overview of how NPs are being utilized to trigger ICD and bolster antitumor immunity. Lastly, we highlight the potential of NPs in combination with immunotherapy to revolutionize cancer treatment.

The theragnostic advances of exosomes in managing leukaemia

Leukaemia, a group of haematological malignancies, presents ongoing diagnosis, prognosis, and treatment challenges. A major obstacle in treating this disease is the development of drug resistance. Overcoming drug resistance poses a significant barrier to effective leukaemia treatment. The emergence of exosome research has unveiled new insights into the probable theragnostic implementations in leukaemia. Various research has exhibited the diagnostic possibilities of exosomes in identifying leukaemia-specific biomarkers, including genetic mutations and fusion transcripts. Additionally, exosomes have been implicated in disease progression and treatment response, rendering them appealing targets for therapeutics. Exosomes, originating from diverse cell types, are instrumental in intercellular communication as they participate in the functional transportation of molecules like proteins, nucleic acids and lipids across space. Exosomes have a dual role in immune regulation, mediating immune suppression and modulating anti-leukaemia immune responses. Interestingly, exosomes can even act as drug transport vehicles. This review delves into the intricate process of exosome biogenesis, shedding light on their formation and release from donor cells. The key mechanisms engaged in exosome biogenesis, for instance, the endosomal sorting complexes required for transport (ESCRT) machinery and ESCRT-independent pathways, are thoroughly discussed. Looking ahead, future approaches that leverage innovative technologies hold the promise of revolutionizing disease management and improving patient outcomes.

Immunogenicity risk assessment of empty capsids present in adeno-associated viral vectors using predictive innate immune responses

Immunogenicity of gene therapy and the impacts on safety and efficacy are of increasing interest in the pharmaceutical industry. Unique structural aspects of gene therapy delivery vectors, such as adeno-associated viral (AAV) vectors, are expected to activate the innate immune system. The risk of innate immune activation is critical to understand due to the potential impacts on safety and on subsequent adaptive immune responses. In this study, we investigated the responses of key innate immune players-dendritic cells, natural killer (NK) cells, and the complement system-to AAV8 capsids. Immunogenicity risk was also predicted in the presence empty AAV capsids for AAV gene therapy. Compared to genome-containing "full" AAV8 capsids, empty AAV8 capsids more strongly induced proinflammatory cytokine production and migration by human and mouse dendritic cells, but the "full" capsid increased expression of co-stimulatory markers. Furthermore, in an NK cell degranulation assay, we found mixtures of empty and full AAV8 capsids to activate expression of TNF-α, IFN-γ, and CD107a more strongly in multiple NK cell populations compared to either capsid type alone. Serum complement C3a was also induced more strongly in the presence of mixed empty and full AAV8 capsid formulations. Risk for innate immune activation suggests the importance to determine acceptable limits of empty capsids. Immunogenicity risk assessment of novel biological modalities will benefit from the aforementioned in vitro innate immune activation assays providing valuable mechanistic information.

Advanced technologies for the development of infectious disease vaccines

Vaccines play a critical role in the prevention of life-threatening infectious disease. However, the development of effective vaccines against many immune-evading pathogens such as HIV has proven challenging, and existing vaccines against some diseases such as tuberculosis and malaria have limited efficacy. The historically slow rate of vaccine development and limited pan-variant immune responses also limit existing vaccine utility against rapidly emerging and mutating pathogens such as influenza and SARS-CoV-2. Additionally, reactogenic effects can contribute to vaccine hesitancy, further undermining the ability of vaccination campaigns to generate herd immunity. These limitations are fuelling the development of novel vaccine technologies to more effectively combat infectious diseases. Towards this end, advances in vaccine delivery systems, adjuvants, antigens and other technologies are paving the way for the next generation of vaccines. This Review focuses on recent advances in synthetic vaccine systems and their associated challenges, highlighting innovation in the field of nano- and nucleic acid-based vaccines.

Cell components of tumor microenvironment in lung adenocarcinoma: Promising targets for small-molecule compounds

ABSTRACT

Lung cancer is one of the most lethal tumors in the world with a 5-year overall survival rate of less than 20%, mainly including lung adenocarcinoma (LUAD). Tumor microenvironment (TME) has become a new research focus in the treatment of lung cancer. The TME is heterogeneous in composition and consists of cellular components, growth factors, proteases, and extracellular matrix. The various cellular components exert a different role in apoptosis, metastasis, or proliferation of lung cancer cells through different pathways, thus contributing to the treatment of adenocarcinoma and potentially facilitating novel therapeutic methods. This review summarizes the research progress on different cellular components with cell-cell interactions in the TME of LUAD, along with their corresponding drug candidates, suggesting that targeting cellular components in the TME of LUAD holds great promise for future theraputic development.

Farnesyl pyrophosphate potentiates dendritic cell migration in autoimmunity through mitochondrial remodelling

Cellular metabolism modulates dendritic cell (DC) maturation and activation. Migratory dendritic cells (mig-DCs) travelling from the tissues to draining lymph nodes (dLNs) are critical for instructing adaptive immune responses. However, how lipid metabolites influence mig-DCs in autoimmunity remains elusive. Here, we demonstrate that farnesyl pyrophosphate (FPP), an intermediate of the mevalonate pathway, accumulates in mig-DCs derived from mice with systemic lupus erythematosus (SLE). FPP promotes mig-DC survival and germinal centre responses in the dLNs by coordinating protein geranylgeranylation and mitochondrial remodelling. Mechanistically, FPP-dependent RhoA geranylgeranylation promotes mitochondrial fusion and oxidative respiration through mitochondrial RhoA-MFN interaction, which subsequently facilitates the resolution of endoplasmic reticulum stress in mig-DCs. Simvastatin, a chemical inhibitor of the mevalonate pathway, restores mitochondrial function in mig-DCs and ameliorates systemic pathogenesis in SLE mice. Our study reveals a critical role for FPP in dictating mig-DC survival by reprogramming mitochondrial structure and metabolism, providing new insights into the pathogenesis of DC-dependent autoimmune diseases.

Exosome-based cell therapy for diabetic foot ulcers: Present and prospect

Diabetic foot ulcers (DFUs) represent a serious complication of diabetes with high incidence, requiring intensive treatment, prolonged hospitalization, and high costs. It poses a severe threat to the patient's life, resulting in substantial burdens on patient and healthcare system. However, the therapy of DFUs remains challenging. Therefore, exploring cell-free therapies for DFUs is both critical and urgent. Exosomes, as crucial mediators of intercellular communication, have been demonstrated potentially effective in anti-inflammation, angiogenesis, cell proliferation and migration, and collagen deposition. These functions have been proven beneficial in all stages of diabetic wound healing. This review aims to summarize the role and mechanisms of exosomes from diverse cellular sources in diabetic wound healing research. In addition, we elaborate on the challenges for clinical application, discuss the advantages of membrane vesicles as exosome mimics in wound healing, and present the therapeutic potential of exosomes and their mimetic vesicles for future clinical applications.

Mouse enteric neurons control intestinal plasmacytoid dendritic cell function via serotonin-HTR7 signaling

Serotonergic neurons in the central nervous system control behavior and mood, but knowledge of the roles of serotonergic circuits in the regulation of immune homeostasis is limited. Here, we employ mouse genetics to investigate the functions of enteric serotonergic neurons in the control of immune responses and find that these circuits regulate IgA induction and boost host defense against oral, but not systemic Salmonella Typhimurium infection. Enteric serotonergic neurons promote gut-homing, retention and activation of intestinal plasmacytoid dendritic cells (pDC). Mechanistically, this neuro-immune crosstalk is achieved through a serotonin-5-HT receptor 7 (HTR7) signaling axis that ultimately facilitates the pDC-mediated differentiation of IgA+ B cells from IgD+ precursors in the gut. Single-cell RNA-seq data further reveal novel patterns of bidirectional communication between specific subsets of enteric neurons and lamina propria DC. Our findings thus reveal a close interplay between enteric serotonergic neurons and gut immune homeostasis that enhances mucosal defense.

IGF2 contributes to the immunomodulatory effects of exosomes from endometrial regenerative cells on experimental colitis

BACKGROUND

Exosomes derived from endometrial regenerative cells (ERC-Exos) can inherit the immunomodulatory function from ERCs, however, whether ERC-Exos exhibit such effect on inflammatory bowel diseases with mucosal immune dysregulation has not been explored. Insulin-like growth factor-Ⅱ (IGF2) is considered to possess the potential to induce an anti-inflammatory phenotype in immune cells. In this study, the contribution of IGF2 in mediating the protective efficacy of ERC-Exos on colitis was investigated.

METHODS

Lentiviral transfection was employed to obtain IGF2-specific knockout ERC-Exos (IGF2-/--ERC-Exos). Experimental colitis mice induced by dextran sulfate sodium (DSS) were divided into the phosphate-buffered saline (untreated), ERC-Exos-treated and IGF2-/--ERC-Exos-treated groups. Colonic histopathological analysis and intestinal barrier function were explored. The infiltration of CD4+ T cells and dendritic cells (DCs) were analyzed by immunofluorescence staining and flow cytometry. The maturation and function of bone marrow-derived dendritic cells (BMDCs) in different exosome administrations were evaluated by flow cytometry, ELISA and the coculture system, respectively.

RESULTS

Compared with the untreated group, ERC-Exos treatment significantly attenuated DSS-induced weight loss, bloody stools, shortened colon length, pathological damage, as well as repaired the weakened intestinal mucosal barrier, including promoting the goblet cells retention, restoring the intestinal barrier integrity and enhancing the expression of tight junction proteins, while the protective effect of exosomes was impaired with the knockout of IGF2 in ERC-Exos. Additionally, IGF2-expressing ERC-Exos decreased the proportions of Th1 and Th17, increased the proportions of Treg, as well as attenuated DC infiltration and maturation in mesenteric lymph nodes and lamina propria of the colitis mice. ERC-Exos were also observed to be phagocytosed by BMDCs and IGF2 is responsible for the modulating effect of ERC-Exos on BMDCs in vitro.

CONCLUSIONS

Exosomes derived from ERCs can exert a therapeutic effect on experimental colitis with remarkable alleviation of the intestinal barrier damage and the abnormal mucosal immune responses. We emphasized that IGF2 plays a critical role for ERC-Exos mediated immunomodulatory function and protection against colitis.

Role of tumor-derived exosomes mediated immune cell reprograming in cancer

Tumor-derived exosomes (TDEs), as topologies of tumor cells, not only carry biological information from the mother, but also act as messengers for cellular communication. It has been demonstrated that TDEs play a key role in inducing an immunosuppressive tumor microenvironment (TME). They can reprogram immune cells indirectly or directly by delivering inhibitory proteins, cytokines, RNA and other substances. They not only inhibit the maturation and function of dendritic cells (DCs) and natural killer (NK) cells, but also remodel M2 macrophages and inhibit T cell infiltration to promote immunosuppression and create a favorable ecological niche for tumor growth, invasion and metastasis. Based on the specificity of TDEs, targeting TDEs has become a new strategy to monitor tumor progression and enhance treatment efficacy. This paper reviews the intricate molecular mechanisms underlying the immunosuppressive effects induced by TDEs to establish a theoretical foundation for cancer therapy. Additionally, the challenges of TDEs as a novel approach to tumor treatment are discussed.

An Experimental Device with Different Widths for Wound Healing Assay

INTRODUCTION

Cellular wound healing assay is an important experimental technique for detecting cell migration in vitro. Scratching on monolayer cells using a pipette tip is commonly used. However, it is difficult to guarantee the scratch with the same width, and the initial scratch width has a large impact on the experimental results for different treatment factors or different cell types. To optimize this assay for diverse experimental requirements, we developed an experimental device capable of generating scratches with variable widths.

METHODS

Our device offers the flexibility of selecting among four widths to create cell scratches, enabling the choice of an optimal initial scratch width for specific cell types and experimental conditions.

RESULTS

This device produced straight, clean wounds with precise widths. Comparing cell growth in the four width wounds, Hepa1-6 and HUMSCs showed the greatest difference in 0.6 cm wound, 143B at 0.9 cm wound and urine-derived stem cells at 1.2 cm wound were significantly different, which suggests that the width of the wounds has a huge impact on the experimental results. Compared to other wound inserts on the market, our device is more efficient and economical.

CONCLUSION

This versatile and practical device provides a valuable solution for studying cell migration, facilitating a deeper understanding of cellular behaviors and the development of therapeutic strategies.

The multiple roles of interferon regulatory factor family in health and disease

Interferon Regulatory Factors (IRFs), a family of transcription factors, profoundly influence the immune system, impacting both physiological and pathological processes. This review explores the diverse functions of nine mammalian IRF members, each featuring conserved domains essential for interactions with other transcription factors and cofactors. These interactions allow IRFs to modulate a broad spectrum of physiological processes, encompassing host defense, immune response, and cell development. Conversely, their pivotal role in immune regulation implicates them in the pathophysiology of various diseases, such as infectious diseases, autoimmune disorders, metabolic diseases, and cancers. In this context, IRFs display a dichotomous nature, functioning as both tumor suppressors and promoters, contingent upon the specific disease milieu. Post-translational modifications of IRFs, including phosphorylation and ubiquitination, play a crucial role in modulating their function, stability, and activation. As prospective biomarkers and therapeutic targets, IRFs present promising opportunities for disease intervention. Further research is needed to elucidate the precise mechanisms governing IRF regulation, potentially pioneering innovative therapeutic strategies, particularly in cancer treatment, where the equilibrium of IRF activities is of paramount importance.

Metabolic regulation of the immune system in health and diseases: mechanisms and interventions

Metabolism, including glycolysis, oxidative phosphorylation, fatty acid oxidation, and other metabolic pathways, impacts the phenotypes and functions of immune cells. The metabolic regulation of the immune system is important in the pathogenesis and progression of numerous diseases, such as cancers, autoimmune diseases and metabolic diseases. The concept of immunometabolism was introduced over a decade ago to elucidate the intricate interplay between metabolism and immunity. The definition of immunometabolism has expanded from chronic low-grade inflammation in metabolic diseases to metabolic reprogramming of immune cells in various diseases. With immunometabolism being proposed and developed, the metabolic regulation of the immune system can be gradually summarized and becomes more and more clearer. In the context of many diseases including cancer, autoimmune diseases, metabolic diseases, and many other disease, metabolic reprogramming occurs in immune cells inducing proinflammatory or anti-inflammatory effects. The phenotypic and functional changes of immune cells caused by metabolic regulation further affect and development of diseases. Based on experimental results, targeting cellular metabolism of immune cells becomes a promising therapy. In this review, we focus on immune cells to introduce their metabolic pathways and metabolic reprogramming, and summarize how these metabolic pathways affect immune effects in the context of diseases. We thoroughly explore targets and treatments based on immunometabolism in existing studies. The challenges of translating experimental results into clinical applications in the field of immunometabolism are also summarized. We believe that a better understanding of immune regulation in health and diseases will improve the management of most diseases.

Hiding in plain sight: Do recruited dendritic cells surround amyloid plaques in Alzheimer's disease?

Over the past decade, human genome-wide association and expression studies have strongly implicated dysregulation of the innate immune system in the pathogenesis of Alzheimer's disease (AD). Single cell mRNA sequencing studies have identified innate immune cell subtypes that are minimally present in normal healthy brain, but whose numbers greatly increase in association with AD pathology. These AD pathology-associated immune cells are putatively the locus for the immune-related AD risk. While the prevailing view is that these immune cells arise from transformation of resident brain microglia, studies across several decades and using multiple techniques and strategies suggest instead that the pathology-associated immune cells are bone-marrow derived hematopoietic cells that are recruited into brain. We critically review this translational literature, emphasizing the strengths and limitations of techniques used to address recruitment and the experimental designs employed. We conclude that the aggregate evidence points toward recruitment into brain of innate immune cells of the myeloid dendritic cell lineage. Recruitment of dendritic cells and their role in AD pathogenesis has broad implications for our understanding of the etiology and pathobiology of AD that impact the strategies to develop new, immune system-targeted therapeutics for this devastating disease.

Apoptotic Vesicles: Therapeutic Mechanisms and Critical Issues

Apoptosis is the most prominent mode of programmed cell death and is necessary for the maintenance of tissue homeostasis. During cell apoptosis, a distinctive population of extracellular vesicles is generated, termed apoptotic vesicles (apoVs). ApoVs inherit a variety of biological molecules such as proteins, RNAs, nuclear components, lipids, and gasotransmitters from their parent cells. ApoVs have shown promising therapeutic potential for inflammation, tumors, immune disorders, and tissue regeneration. In addition, apoVs can be used as drug carriers, vaccine development, and disease diagnosis. Recently, apoVs have been used in clinical trials to treat a variety of diseases, such as temporomandibular joint osteoarthritis and the regeneration of functional alveolar bone. Here, we review the history of apoV research, current preclinical and clinical studies, and the potential issues of apoV application.

An Immunohistochemical Study on the Role of CD83+ Dendritic Cells (DCs) in Malignant and Benign Lesions of the Human Cervix

Background Dendritic cells (DCs) are a group of cells that mainly function as antigen-presenting cells in the human body. Proper knowledge and understanding of such cells in the human cervix would be beneficial for understanding the role of CD83+ cells in benign and malignant lesions of the cervix. Materials and methods This retrospective study was performed on cervical specimens. After processing, the CD83+ cells were counted for every 20 high-power fields. The average count per high power field (HPF) was then calculated. The CD83+ cell distributions in cervicitis, cervical dysplasia, and cervical carcinoma were then analyzed.  Results A total of 30 cervical specimens were studied. Of these, 16 were cervicitis and seven were squamous cell carcinoma. Vaginal bleeding was the most common presentation in 21 patients. The mean age was 44.7 years. The mean CD83+ DCs in benign lesions was 1.75 and in malignant tissues was 12.26 per HPF (P<0.001). The area under the curve suggested a 100% sensitivity and specificity of CD83 in distinguishing benign and malignant lesions. The receiver operating characteristic (ROC) curve indicated that the probability of malignancy is higher if the number of CD83+ DCS is more than 179.50/20 HPF. Conclusions Dendritic cells play a major role in the tumoricidal activities of the host cervical tissues. Malignant cervical tissue possesses a higher concentration of CD83+ DCs than benign ones, with 100% sensitivity and specificity. This research work on CD83+ DCs in the cervix would pave the way for further research on the immune functions of the human body.

Intragastric administration of transamidated gliadin interferes with the systemic and intestinal immune responses to wheat gliadin in DQ8 transgenic mice

We have previously shown the ability of transamidated gluten (spf) to modulate both innate and adaptive intestinal immunity elicited by wheat gliadin in HLA-DQ8 transgenic mice (DQ8 mice), a model of gluten sensitivity. Herein, we evaluated the influence of spf when administered intragastrically on the immune response to native gliadin in DQ8 mice. To address the issue, we analysed three regimens of antigen administration: before immunisation (pre-treatment), during immunisation (co-treatment) and through breast milk during the lactating phase (suckling treatment). Mice were immunised mucosally by intranasal delivery of digested wheat gliadin along with cholera toxin in multiple doses. After sacrifice, isolated spleen and mesenteric lymph node (MLN) cells were challenged in vitro and the cytokine profile of culture supernatants assessed by ELISA and multiparametric assay. We found that only pre-treatment with spf was effective in down-regulating the gliadin-specific IFN-γ response and only in spleen cells. Interestingly, spf pre-treatment also induced systemic IL-6, IL-17A and TNF-α. By contrast, we found that spf pre-treatment upregulated INF-γ in MLN but also significantly decreased IL-2. In conclusion, our data provide evidence that the preventive intragastric administration of transamidated gluten is able to interfere with the classical cytokine profile induced by gliadin via mucosal immunisation in a transgenic model expressing one of the HLA molecules associated with coeliac disease.

Comparative Ability of Various Immunosuppressants as Adjuvants on the Activity of T1D Vaccine

Background: Type 1 diabetes (T1D) is an autoimmune disorder characterised by the destruction of insulin-producing beta cells in the pancreatic islets, resulting from a breakdown in immunological tolerance. Currently, T1D treatment primarily relies on insulin replacement or immunosuppressive therapies. However, these approaches often have significant drawbacks, including adverse effects, high costs, and limited long-term efficacy. Consequently, there is a pressing need for innovative immunotherapeutic strategies capable of inducing antigen-specific tolerance and protecting beta cells from autoimmune destruction. Among the various antigens, β-cell antigens like 65 kDa glutamic acid decarboxylase (GAD65) have been explored as vaccine candidates for T1D. Despite their potential, their effectiveness in humans remains modest, necessitating the use of appropriate adjuvants to enhance the vaccine's protective effects. Methods: In this study, we evaluated the therapeutic potential of kynurenine (KYN), dexamethasone (DXMS), tacrolimus (FK506), and aluminium hydroxide (Alum) in combination with the GAD65 phage vaccine as adjuvants. Results: Our findings demonstrate that KYN, when used in conjunction with the GAD65 vaccine, significantly enhances the vaccine's immunosuppressive effects. Compared to dexamethasone, FK506, and Alum adjuvants, KYN more effectively reduced the incidence and delayed the onset of T1D, preserved β-cell function, and promoted the induction of regulatory T cells and antigen-specific tolerance. These results suggest that KYN combined with vaccines could offer superior preventive and therapeutic benefits for T1D compared to existing treatments. Additionally, we investigated the dose-dependent effects of the GAD65 vaccine by including a low-dose group in our study. The results indicated that reducing the vaccine dose below 1010 plaque-forming units (pfu) did not confer any protective advantage or therapeutic benefit in combination with KYN. This finding underscores that 1010 pfu is the minimum effective dose for the GAD65 vaccine in achieving a protective response. In conclusion, KYN shows considerable promise as an adjuvant for the GAD65 vaccine in T1D therapy, potentially offering a more effective and durable treatment option than current immunosuppressive strategies.

Dendritic cell force-migration coupling on aligned fiber networks

Dendritic cells (DCs) are antigen-presenting cells that reside in peripheral tissues and are responsible for initiating adaptive immune responses. As gatekeepers of the immune system, DCs need to continuously explore their surroundings, for which they can rapidly move through various types of connective tissue and basement membranes. DC motility has been extensively studied on flat 2D surfaces, yet the influences of a contextual 3D fibrous environment still need to be described. Using ECM-mimicking suspended fiber networks, we show how immature DCs (iDCs) engage in migratory cycles that allow them to transition from persistent migration to slow migratory states. For a subset of iDCs with high migratory potential, we report the organization of protrusions at the front of the cell body, which reverses upon treatment with inflammation agent PGE2. We identify an unusual migratory response to aligned fiber networks, whereby iDCs use filamentous protrusions to attach laterally and exert forces on fibers to migrate independent of fiber alignment. Increasing the fiber diameter from 200 to 500 nm does not significantly affect the migratory response; however, iDCs respond by forming denser actin bundles around larger diameters. Overall, the correlation between force-coupling and random migration of iDCs in aligned fibrous topography offers new insights into how iDCs might move in fibrous environments in vivo.

The role of immune cells in the pathogenesis of connective tissue diseases-associated pulmonary arterial hypertension

Connective tissue diseases-related pulmonary arterial hypertension (CTD-PAH) is a disease characterized by an elevated pulmonary artery pressure that arises as a complication of connective tissue diseases. The number of patients with CTD-PAH accounts for 25.3% of all PAH patients. The main pathological features of CTD-PAH are thickening of intima, media and adventitia of pulmonary arterioles, increased pulmonary vascular resistance, autoimmune activation and inflammatory reaction. It is worth noting that abnormal immune activation will produce autoantibodies and release cytokines, and abnormal immune cell recruitment will promote inflammatory environment and vascular remodeling. Therefore, almost all forms of connective tissue diseases are related to PAH. In addition to general therapy and targeted drug therapy for PAH, high-dose glucocorticoid combined with immunosuppressant can quickly alleviate and stabilize the basic CTD-PAH disease. Given this, the development of therapeutic approaches targeting immune dysregulation and heightened inflammation is recognized as a promising strategy to prevent or reverse the progression of CTD-PAH. This review explores the potential mechanisms by which immune cells contribute to the development of CTD-PAH and examines the clinical application of immunosuppressive therapies in managing CTD-PAH.

Oral administration of Lactobacillus plantarum expressing aCD11c modulates cellular immunity alleviating inflammatory injury due to Klebsiella pneumoniae infection

BACKGROUND

Klebsiella pneumoniae (KP), responsible for acute lung injury (ALI) and inflammation of the gastrointestinal tract, is a zoonotic pathogen that poses a threat to livestock farming worldwide. Nevertheless, there is currently no validated vaccine to prevent KP infection. The development of mucosal vaccines against KP using Lactobacillus plantarum (L. plantarum) is an effective strategy.

RESULTS

Firstly, the L. plantarum strains NC8-pSIP409-aCD11c' and NC8-pLc23-aCD11c were constructed via homologous recombination to express the aCD11c protein either inducibly or constitutively. Both NC8-pSIP409-aCD11c' and NC8-pLc23-aCD11c strains could enhance the adhesion and invasion of L. plantarum on bone marrow-derived dendritic cells (BMDCs), and stimulate the activation of BMDCs compared to the control strain NC8-pSIP409 in vitro. Following oral immunization of mice with NC8-pSIP409-aCD11c' and NC8-pLc23-aCD11c, the cellular, humoral, and mucosal immunity were significantly improved, as evidenced by the increased expression of CD4+ IL-4+ T cells in the spleen, IgG in serum, and secretory IgA (sIgA) in the intestinal lavage fluid (ILF). Furthermore, the protective effects of L. plantarum against inflammatory damage caused by KP infection were confirmed by assessing the bacterial loads in various tissues, lung wet/dry ratio (W/D), levels of inflammatory cytokines, and histological evaluation, which influenced T helper 17 (Th17) and regulatory T (Treg) cells in peripheral blood and lung.

CONCLUSIONS

Both the inducible and constitutive L. plantarum strains NC8-pSIP409-aCD11c' and NC8-pLc23-aCD11c have been found to stimulate cellular and humoral immunity levels and alleviate the inflammatory response caused by KP infection. These findings have provided a basis for the development of a novel vaccine against KP.

Tumor antigen presentation and the associated signal transduction during carcinogenesis

Numerous developments have been achieved in the study and treatment of cancer throughout the decades that it has been common. After decades of research, about 100 different kinds of cancer have been found, each with unique subgroups within certain organs. This has significantly expanded our understanding of the illness. A mix of genetic, environmental, and behavioral variables contribute to the complicated and diverse process of cancer formation. Mutations, or changes in the DNA sequence, are crucial to the development of cancer. These mutations have the ability to downregulate the expression and function of Major Histocompatibility Complex class I (MHC I) and MHCII receptors, as well as activate oncogenes and inactivate tumor suppressor genes. Cancer cells use this tactic to avoid being recognized by cytotoxic CD8+T lymphocytes, which causes issues with antigen presentation and processing. This review goes into great length into the PI3K pathway, changes to MHC I, and positive impacts of tsMHC-II on disease-free survival and overall survival and the involvement of dendritic cells (DCs) in different tumor microenvironments. The vital functions that the PI3K pathway and its link to the mTOR pathway are highlighted and difficulties in developing effective cancer targeted therapies and feedback systems has also been mentioned, where resistance mechanisms include RAS-mediated oncogenic changes and active PI3K signalling.

CC chemokines Modulate Immune responses in Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension (PH) represents a progressive condition characterized by the remodeling of pulmonary arteries, ultimately culminating in right heart failure and increased mortality rates. Substantial evidence has elucidated the pivotal role of perivascular inflammatory factors and immune dysregulation in the pathogenesis of PH. Chemokines, a class of small secreted proteins, exert precise control over immune cell recruitment and functionality, particularly with respect to their migration to sites of inflammation. Consequently, chemokines emerge as critical drivers facilitating immune cell infiltration into the pulmonary tissue during inflammatory responses. This review comprehensively examines the significant contributions of CC chemokines in the maintenance of immune cell homeostasis and their pivotal role in regulating inflammatory responses. The central focus of this discussion is directed towards elucidating the precise immunoregulatory actions of CC chemokines concerning various immune cell types, including neutrophils, monocytes, macrophages, lymphocytes, dendritic cells, mast cells, eosinophils, and basophils, particularly in the context of pH processes. Furthermore, this paper delves into an exploration of the underlying pathogenic mechanisms that underpin the development of PH. Specifically, it investigates processes such as cellular pyroptosis, examines the intricate crosstalk between bone morphogenetic protein receptor type 2 (BMPR2) mutations and the immune response, and sheds light on key signaling pathways involved in the inflammatory response. These aspects are deemed critical in enhancing our understanding of the complex pathophysiology of PH. Moreover, this review provides a comprehensive synthesis of findings from experimental investigations targeting immune cells and CC chemokines.

AIM OF REVIEW

In summary, the inquiry into the inflammatory responses mediated by CC chemokines and their corresponding receptors, and their potential in modulating immune reactions, holds promise as a prospective avenue for addressing PH. The potential inhibition of CC chemokines and their receptors stands as a viable strategy to attenuate the inflammatory cascade and ameliorate the pathological manifestations of PH. Nonetheless, it is essential to acknowledge the current state of clinical trials and the ensuing progress, which regrettably appears to be less than encouraging. Substantial hurdles exist in the successful translation of research findings into clinical applications. The intention is that such emphasis could potentially foster the advancement of potent therapeutic agents presently in the process of clinical evaluation. This, in turn, may further bolster the potential for effective management of PH.

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 (DCs) are specialized antigen-presenting cells (APCs) that prime adaptive immune responses, such as those involved in the development of oral tolerance and food allergies. The DC 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 DCs or a subset of newly identified RORγt+ APCs to induce the development of gut peripheral regulatory T cells. However, DCs 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. DCs 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 DCs that prime allergic sensitization and discover methods to selectively initiate a tolerogenic program in APCs.