Evaluating the photodynamic efficacy of nebulized curcumin-loaded liposomes prepared by thin-film hydration and dual centrifugation: In vitro and in ovo studies

Lung cancer, one of the most common causes of high mortality worldwide, still lacks appropriate and convenient treatment options. Photodynamic therapy (PDT) has shown promising results against cancer, especially in recent years. However, pulmonary drug delivery of the predominantly hydrophobic photosensitizers still represents a significant obstacle. Nebulizing DPPC/Cholesterol liposomes loaded with the photosensitizer curcumin via a vibrating mesh nebulizer might overcome current restrictions. In this study, the liposomes were prepared by conventional thin-film hydration and two other methods based on dual centrifugation. The liposomes' physicochemical properties were determined before and after nebulization, showing that liposomes do not undergo any changes. However, morphological characterization of the differently prepared liposomes revealed structural differences between the methods in terms of lamellarity. Internalization of curcumin in lung adenocarcinoma (A549) cells was visualized and quantified. The generation of reactive oxygen species because of the photoreaction was also proven. The photodynamic efficacy of the liposomal formulations was tested against A549 cells. They revealed different phototoxic responses at different radiant exposures. Furthermore, the photodynamic efficacy was investigated after nebulizing curcumin-loaded liposomes onto xenografted tumors on the CAM, followed by irradiation, and evaluated using positron emission tomography/computed tomography and histological analysis. A decrease in tumor metabolism could be observed. Based on the efficacy of curcumin-loaded liposomes in 2D and 3D models, liposomes, especially with prior film formation, can be considered a promising approach for PDT against lung cancer.

Integrating bulk and single-cell sequencing data to construct a Scissor+ dendritic cells prognostic model for predicting prognosis and immune responses in ESCC

Esophageal squamous cell carcinoma (ESCC) is characterized by molecular heterogeneity with various immune cell infiltration patterns, which have been associated with therapeutic sensitivity and resistance. In particular, dendritic cells (DCs) are recently discovered to be associated with prognosis and survival in cancer. However, how DCs differ among ESCC patients has not been fully comprehended. Recently, the advance of single-cell RNA sequencing (scRNA-seq) enables us to profile the cell types, states, and lineages in the heterogeneous ESCC tissues. Here, we dissect the ESCC tumor microenvironment at high resolution by integrating 192,078 single cells from 60 patients, including 4379 DCs. We then used Scissor, a method that identifies cell subpopulations from single-cell data that are associated bulk samples with genomic and clinical information, to stratify DCs into Scissorhi and Scissorlow subtypes. We applied the Scissorhi gene signature to stratify ESCC scRNAseq patient, and we found that PD-L1, TIGIT, PVR and IL6 ligand-receptor-mediated cell interactions existed mainly in Scissorhi patients. Finally, based on the Scissor results, we successfully developed a validated prognostic risk model for ESCC and further validated the reliability of the risk prediction model by recruiting 40 ESCC clinical patients. This information highlights the importance of these genes in assessing patient prognosis and may help in the development of targeted or personalized therapies for ESCC.

Roles of IRF4 in various immune cells in systemic lupus erythematosus

Interferon regulatory factor 4 (IRF4) is a member of IRF family of transcription factors which mainly regulates the transcription of IFN. IRF4 is restrictively expressed in immune cells such as T and B cells, macrophages, as well as DC. It is essential for the development and function of these cells. Since these cells take part in the homeostasis of the immune system and dysfunction of them contributes to the initiation and progress of systemic lupus erythematosus (SLE), the roles of IRF4 in the SLE development becomes an important topic. Here we systemically discuss the biological characteristics of IRF4 in various immune cells and analyze the pathologic effects of IRF4 alteration in SLE and the potential targeting therapeutics of SLE.

cGAS-STING pathway mediates activation of dendritic cell sensing of immunogenic tumors

Type I interferons (IFN-I) play pivotal roles in tumor therapy for three decades, underscoring the critical importance of maintaining the integrity of the IFN-1 signaling pathway in radiotherapy, chemotherapy, targeted therapy, and immunotherapy. However, the specific mechanism by which IFN-I contributes to these therapies, particularly in terms of activating dendritic cells (DCs), remains unclear. Based on recent studies, aberrant DNA in the cytoplasm activates the cyclic GMP-AMP synthase (cGAS)- stimulator of interferon genes (STING) signaling pathway, which in turn produces IFN-I, which is essential for antiviral and anticancer immunity. Notably, STING can also enhance anticancer immunity by promoting autophagy, inflammation, and glycolysis in an IFN-I-independent manner. These research advancements contribute to our comprehension of the distinctions between IFN-I drugs and STING agonists in the context of oncology therapy and shed light on the challenges involved in developing STING agonist drugs. Thus, we aimed to summarize the novel mechanisms underlying cGAS-STING-IFN-I signal activation in DC-mediated antigen presentation and its role in the cancer immune cycle in this review.

Dendritic cell-derived exosomes (Dex): Underlying the role of exosomes derived from diverse DC subtypes in cancer pathogenesis

Exosomes are nanometric membrane vesicles of late endosomal origin that are released by most, if not all, cell types as a sophisticated means of intercellular communication. They play an essential role in the movement of materials and information between cells, transport a variety of proteins, lipids, RNA, and other vital data, and over time, they become an essential part of the drug delivery system and a marker for the early detection of many diseases. Dendritic cells have generated interest in cancer immunotherapy due to their ability to initiate and modify effective immune responses. Apart from their cytokine release and direct interactions with other cell types, DCs also emit nanovesicles, such as exosomes, that contribute to their overall activity. Numerous studies have demonstrated exosomes to mediate and regulate immune responses against cancers. Dendritic cell-derived exosomes (DCs) have attracted a lot of attention as immunotherapeutic anti-cancer treatments since it was found that they contain functional MHC-peptide complexes along with a variety of other immune-stimulating components that together enable immune cell-dependent tumor rejection. By enhancing tumor and immunosuppressive immune cells or changing a pro-inflammatory milieu to inhibit tumor advancement, exosomes generated from dendritic cells can initiate and support tumor growth. This study reviewed the immunogenicity of dendritic cell-derived exosomes and strategies for expanding their immunogenic potential as novel and effective anti-cancer therapies.

Telomere biology disorders may manifest as common variable immunodeficiency (CVID)

Telomere biology disorders (TBD) are caused by germline pathogenic variants in genes related to telomere maintenance and are characterized by critically short telomeres. In contrast to classical dyskeratosis congenita (DC), which is typically diagnosed in infancy, adult or late onset TBD frequently lack the typical DC triad and rather show variable organ manifestations and a cryptic disease course, thus complicating its diagnosis. Common variable immunodeficiency (CVID), on the other hand, is a primary antibody deficiency (PAD) syndrome. PADs are a heterogenous group of diseases characterized by hypogammaglobulinemia which occurs due to dysfunctional B lymphocytes and additional autoimmune and autoinflammatory complications. Genetic screening reveals a monogenic cause in a subset of CVID patients (15-35%). In our study, we screened the exomes of 491 CVID patients for the occurrence of TBD-related variants in 13 genes encoding for telomere/telomerase-associated proteins, which had previously been linked to the disease. We found 110/491 patients (22%) carrying 91 rare candidate variants in these 13 genes. Following the American College of Medical Genetics and Genomics (ACMG) guidelines, we classified two variants as benign, two as likely benign, 64 as variants of uncertain significance (VUS), four as likely pathogenic, and one heterozygous variant in an autosomal recessive disease gene as pathogenic. We performed telomere length measurement in 42 of the 110 patients with candidate variants and CVID. Two of these 42 patients showed significantly shorter telomeres compared to controls in both lymphocytes and granulocytes. Following the evaluation of the published literature and the patient's manifestations, we re-classified two VUS as likely pathogenic variants. Thus, 0.5-1% of all CVID patients in our study carry possibly pathogenic variants in telomere/telomerase-associated genes. Our data adds CVID to the broad clinical spectrum of cryptic adult-onset TBD. As the molecular diagnosis greatly impacts patient management and treatment strategies, we advise inclusion of all TBD-associated genes-despite their low prevalence-into the molecular screening of patients with antibody deficiencies.

LW-213 induces immunogenic tumor cell death via ER stress mediated by lysosomal TRPML1

Dying tumor cells release biological signals that exhibit antigenicity, activate cytotoxic T lymphocytes, and induce immunogenic cell death (ICD), playing a key role in immune surveillance. We demonstrate that the flavonoid LW-213 activates endoplasmic reticulum stress (ERS) in different tumor cells and that the lysosomal calcium channel TRPML1 mediates the ERS process in human cellular lymphoma Hut-102 cells. Apoptotic tumor cells induced by ERS often possess immunogenicity. Tumor cells treated with LW-213 exhibit damage-associated molecular patterns (DAMPs), including calreticulin translocation to the plasma membrane and extracellular release of ATP and HMGB1. When co-cultured with antigen-presenting cells (APCs), LW-213-treated tumor cells activated APCs. Two groups of C57BL/6J mice were inoculated with Lewis cells: a "vaccine group", which demonstrated that LW-213-treated tumor cells promote the maturation of dendritic cells and increase CD8+ T cells infiltration in the tumor microenvironment and a "pharmacodynamic group", treated with a combination of LW-213 and PD1/PD-L1 inhibitor (BMS-1), which reduced tumor growth and significantly prolonged the survival time of mice in the "pharmacodynamic group". Therefore, LW-213 can be developed as a novel ICD inducer, providing a new concept for antitumor immunotherapy.

Resting-state functional magnetic resonance imaging alterations in borderline personality disorder: A systematic review

BACKGROUND

Borderline personality disorder (BPD) is a severe psychiatric disorder characterized by emotion dysregulation, impulsivity, and interpersonal disturbances. Several structural and functional neuroimaging abnormalities have been described in BPD. In particular, resting-state functional magnetic resonance imaging (rs-fMRI) studies have recently suggested various connectivity alterations within and between large-scale brain networks in BPD. This review aimed at providing an updated summary of the evidence reported by the available rs-fMRI studies in BPD individuals.

METHODS

A search on PubMed, Scopus, and Web of Science was performed to identify rs-fMRI alterations in BPD. A total of 15 studies met our inclusion criteria.

RESULTS

Overall, aberrant resting-state functional connectivity (rs-FC) within and between default mode network (DMN), salience network (SN), and central executive network (CEN) were observed in BPD compared to healthy controls, as well as selective functional impairments in bilateral amygdala, anterior and posterior cingulate cortex, hippocampus, and prefrontal cortex.

LIMITATIONS

The observational design, small sample size, prevalence of females, high rates of concurrent comorbidities and medications, and heterogeneity across imaging methodologies limit the generalizability of the results.

CONCLUSIONS

The identification of altered patterns of rs-FC within and between selective brain networks, including DMN, SN, and CEN, could further our knowledge of the clinical symptoms of BPD, and therefore, future studies with multimodal methodologies and longitudinal designs are warranted to further explore the neural correlates of this disorder.

Cyclometalated iridium(III) complexes induce immunogenic cell death in HepG2 cells via paraptosis

Immunotherapy has been shown to provide superior antitumor efficacy by activating the innate immune system to recognize, attack and eliminate tumor cells without seriously harming normal cells. Herein, we designed and synthesized three new cyclometalated iridium(III) complexes (Ir1, Ir2, Ir3) then evaluated their antitumor activity. When co-incubated with HepG2 cells, the complex Ir1 localized in the lysosome, where it induced paraptosis and endoplasmic reticulum stress (ER stress). Notably, Ir1 also induced immunogenic cell death (ICD), promoted dendritic cell maturation that enhanced effector T cell chemotaxis to tumor tissues, down-regulated proportions of immunosuppressive regulatory T cells within tumor tissues and triggered activation of antitumor immunity throughout the body. To date, Ir1 is the first reported iridium(III) complex-based paraptosis inducer to successfully induce tumor cell ICD. Furthermore, Ir1 induced ICD of HepG2 cells without affecting cell cycle or reactive oxygen species levels.

Dendritic Cell Vaccination in Non-Small Cell Lung Cancer: Remodeling the Tumor Immune Microenvironment

Non-small-cell lung cancer (NSCLC) remains one of the leading causes of death worldwide. While NSCLCs possess antigens that can potentially elicit T cell responses, defective tumor antigen presentation and T cell activation hinder host anti-tumor immune responses. The NSCLC tumor microenvironment (TME) is composed of cellular and soluble mediators that can promote or combat tumor growth. The composition of the TME plays a critical role in promoting tumorigenesis and dictating anti-tumor immune responses to immunotherapy. Dendritic cells (DCs) are critical immune cells that activate anti-tumor T cell responses and sustain effector responses. DC vaccination is a promising cellular immunotherapy that has the potential to facilitate anti-tumor immune responses and transform the composition of the NSCLC TME via tumor antigen presentation and cell-cell communication. Here, we will review the features of the NSCLC TME with an emphasis on the immune cell phenotypes that directly interact with DCs. Additionally, we will summarize the major preclinical and clinical approaches for DC vaccine generation and examine how effective DC vaccination can transform the NSCLC TME toward a state of sustained anti-tumor immune signaling.

Conventional and non-conventional antigen presentation by mast cells

Mast cells (MCs) are multifunctional immune cells that express a diverse repertoire of surface receptors and pre-stored bioactive mediators. They are traditionally recognized for their involvement in allergic and inflammatory responses, yet there is a growing body of literature highlighting their contributions to mounting adaptive immune responses. In particular, there is growing evidence that MCs can serve as antigen-presenting cells, owing to their often close proximity to T cells in both lymphoid organs and peripheral tissues. Recent studies have provided compelling support for this concept, by demonstrating the presence of antigen processing and presentation machinery in MCs and their ability to engage in classical and non-classical pathways of antigen presentation. However, there remain discrepancies and unresolved questions regarding the extent of the MC's capabilities with respect to antigen presentation. In this review, we discuss our current understanding of the antigen presentation by MCs and its influence on adaptive immunity.

Blocking Tim-3 enhances the anti-tumor immunity of STING agonist ADU-S100 by unleashing CD4+ T cells through regulating type 2 conventional dendritic cells

Rationale: An immunosuppressive tumor microenvironment (TME) is a major obstacle in tumor immunotherapy. Stimulator of interferon genes (STING) agonists trigger an inflammatory innate immune response to potentially overcome tumor immunosuppression. While STING agonists may hold promise as potential cancer therapy agents, tumor resistance to STING monotherapy has emerged in clinical trials, and the mechanisms remain unclear. Methods: The in vivo anti-tumor immunity of STING agonist ADU-S100 (S100), plus anti-T cell immunoglobulin and mucin-domain containing-3 antibody (αTim-3) were measured using murine tumor models. Tumor-specific T cell activation and alterations in the TME were detected using flow cytometry. The maturation and function of dendritic cells (DC) were also measured using flow cytometry, and the importance of CD4+ T cells in combination therapy was measured by blocking antibodies. Additionally, the effect of S100 on CD4+ T was verified via in vitro assays. Lastly, the impact of conventional dendritic cells (cDC) 2 with a high expression of Tim-3 on survival or therapeutic outcomes was further evaluated in human tumor samples. Results: S100 boosted CD8+ T by activating cDC1 but failed to initiate cDC2. Mechanistically, the administration of S100 results in an upregulation of Tim-3 expressed in cDC2 (Tim-3+cDC2) in both mice and humans, which is immunosuppressive. Tim-3+cDC2 restrained CD4+ T and attenuated the CD4+ T-driven anti-tumor response. Combining S100 with αTim-3 effectively promoted cDC2 maturation and antigen presentation, releasing CD4+ T cells, thus reducing tumor burden while prolonging survival. Furthermore, high percentages of Tim-3+cDC2 in the human TME predicted poor prognosis, whereas the abundance of Tim-3+cDC2 may act as a biomarker for CD4+ T quality and a contributing indicator for responsiveness to immunotherapy. Conclusion: This research demonstrated that blocking Tim-3 could enhance the anti-tumor immunity of STING agonist ADU-S100 by releasing CD4+ T cells through regulating cDC2. It also revealed an intrinsic barrier to ADU-S100 monotherapy, besides providing a combinatorial strategy for overcoming immunosuppression in tumors.

The interplay between innate lymphoid cells and microbiota

Innate lymphoid cells (ILCs) are mainly resident in mucosal tissues such as gastrointestinal tract and respiratory tract, so they are closely linked to the microbiota. ILCs can protect commensals to maintain homeostasis and increase resistance to pathogens. Moreover, ILCs also play an early role in defense against a variety of pathogenic microorganisms including pathogenic bacteria, viruses, fungi and parasites, before the intervention of adaptive immune system. Due to the lack of adaptive antigen receptors expressed on T cells and B cells, ILCs need to use other means to sense the signals of microbiota and play a role in corresponding regulation. In this review, we focus on and summarize three major mechanisms used in the interaction between ILCs and microbiota: the mediation of accessory cells represented by dendritic cells; the metabolic pathways of microbiota or diet; the participation of adaptive immune cells.

Chorionicity-associated variation in metabolic phenotype of cord blood in twin

BACKGROUND

Monochorionic (MC) twins present a higher incidence of unfavorable clinical perinatal outcomes than dichorionic (DC) twins, often in association with placental vascular anastomosis. In this study, we profiled the umbilical cord plasma metabolomes of uncomplicated MC and DC twin pregnancies and related these to several offspring outcomes, previously associated with birthweight.

METHODS

Umbilical vein blood samples were collected at birth from 25 pairs of uncomplicated MC twins and 24 pairs of uncomplicated DC twins. The samples were subjected to gas chromatography-mass spectrometry-based metabolomics. 152 metabolites were identified from the cord plasma samples of MC and DC twins. Partial least squares discriminant analysis and pathway analysis were performed to compare within DC/MC twin pairs and between DC and MC twins. A generalized estimating equation (GEE) model was utilized to explore the correlation between metabolic differences and birthweight discordance within and between twin pairs.

RESULTS

Our study revealed clear differences between the metabolite profiles of umbilical cord plasma of MC and DC twins. Metabolite profiles in MC within twin pairs and DC within twin pairs were characterized by the differences in 2 - hydroxyglutaramic acid levels and nicotinamide levels, respectively. The metabolic pathways of GSH, tryptophan, and fatty acid metabolism, were significantly downregulated in MC twins compared to DC twins. In addition, the concentration of caffeine and decamethyl-cyclopentasiloxane (D5) was positively correlated with birthweight in MC and DC twins.

CONCLUSION

This study demonstrated that the altered metabolites in umbilical plasma made contributions to the different chorionicities between uncomplicated MC twins and DC twins. The chorionicity of twins seems to affect the metabolic cross-talk between co-twin pairs and be related to birthweight discordance of twins.

Putrescine accelerates the differentiation of bone marrow derived dendritic cells via inhibiting phosphorylation of STAT3 at Tyr705

Dendritic cells (DCs) play pivotal roles in immune responses. The differentiation and function of DCs are regulated by environmental metabolites. Putrescine is ubiquitous in various metabolic microenvironments and its immunoregulation has been of increasing interest. However, the mechanisms associated with its DC-induced immunoregulation remain unclear. In this study, we found putrescine promoted induction of immature bone marrow derived DCs (BMDCs), along with the increased phagocytosis and migration, and altered cytokine secretion in immature BMDCs. Transcriptomic profiles indicated significantly impaired inflammatory-related pathways, elevated oxidative phosphorylation, and decreased p-STAT3 (Tyr705) expression. Additionally, putrescine performed minor influence on the lipopolysaccharide (LPS)-induced maturation of BMDCs but significantly impaired LPS-induced DC-elicited allogeneic T-cell proliferation as well as the cytokine secretion. Furthermore, molecular docking and dynamics on the conjugation between putrescine and STAT3 revealed that putrescine could be stably bound to the hydrophilic cavity in STAT3 and performed significant influence on the Tyr705 phosphorylation. CUT&Tag analysis uncovered altered motifs, downregulated IFN-γ response, and upregulated p53 pathway in Putrescine group compared with Control group. In summary, our results demonstrated for the first time that putrescine might accelerate the differentiation of BMDCs by inhibiting the phosphorylation of STAT3 at Tyr705. Given that both DCs and putrescine have ubiquitous and distinct roles in various immune responses and pathogeneses, our findings may provide more insights into polyamine immunoregulation on DCs, as well as distinct strategies in the clinical utilization of DCs by targeting polyamines.

Tissue injury and leukocyte changes in post-acute sequelae of SARS-CoV-2: review of 2833 post-acute patient outcomes per immune dysregulation and microbial translocation in long COVID

A significant number of persons with coronavirus disease 2019 (COVID-19) experience persistent, recurrent, or new symptoms several months after the acute stage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This phenomenon, termed post-acute sequelae of SARS-CoV-2 (PASC) or long COVID, is associated with high viral titers during acute infection, a persistently hyperactivated immune system, tissue injury by NETosis-induced micro-thrombofibrosis (NETinjury), microbial translocation, complement deposition, fibrotic macrophages, the presence of autoantibodies, and lymphopenic immune environments. Here, we review the current literature on the immunological imbalances that occur during PASC. Specifically, we focus on data supporting common immunopathogenesis and tissue injury mechanisms shared across this highly heterogenous disorder, including NETosis, coagulopathy, and fibrosis. Mechanisms include changes in leukocyte subsets/functions, fibroblast activation, cytokine imbalances, lower cortisol, autoantibodies, co-pathogen reactivation, and residual immune activation driven by persistent viral antigens and/or microbial translocation. Taken together, we develop the premise that SARS-CoV-2 infection results in PASC as a consequence of acute and/or persistent single or multiple organ injury mediated by PASC determinants to include the degree of host responses (inflammation, NETinjury), residual viral antigen (persistent antigen), and exogenous factors (microbial translocation). Determinants of PASC may be amplified by comorbidities, age, and sex.

Longitudinal analysis of DC subsets in patients with ovarian cancer: Implications for immunotherapy

Background

The use of circulating cDC1 to generate anti-cancer vaccines is among the most promising approaches to overcome the limited immunogenicity and clinical efficacy of monocyte-derived DC. However, the recurrent lymphopenia and the reduction of DC numbers and functionality in patients with cancer may represent an important limitation of such approach. In patients with ovarian cancer (OvC) that had received chemotherapy, we previously showed that cDC1 frequency and function were reduced.

Methods

We recruited healthy donors (HD, n=7) and patients with OvC at diagnosis and undergoing interval debulking surgery (IDS, n=6), primary debulking surgery (PDS, n=6) or at relapse (n=8). We characterized longitudinally phenotypic and functional properties of peripheral DC subsets by multiparametric flow cytometry.

Results

We show that the frequency of cDC1 and the total CD141+ DC capacity to take up antigen are not reduced at the diagnosis, while their TLR3 responsiveness is partially impaired in comparison with HD. Chemotherapy causes cDC1 depletion and increase in cDC2 frequency, but mainly in patients belonging to the PDS group, while in the IDS group both total lymphocytes and cDC1 are preserved. The capacity of total CD141+ DC and cDC2 to take up antigen is not impacted by chemotherapy, while the activation capacity upon Poly(I:C) (TLR3L) stimulation is further decreased.

Conclusions

Our study provides new information about the impact of chemotherapy on the immune system of patients with OvC and sheds a new light on the importance of considering timing with respect to chemotherapy when designing new vaccination strategies that aim at withdrawing or targeting specific DC subsets.

Use of Hu-PBL Mice to Study Pathogenesis of Human-Restricted Viruses

Different humanized mouse models have been developed to study human diseases such as autoimmune illnesses, cancer and viral infections. These models are based on the use of immunodeficient mouse strains that are transplanted with human tissues or human immune cells. Among the latter, mice transplanted with hematopoietic stem cells have been widely used to study human infectious diseases. However, mouse models built upon the transplantation of donor-specific mature immune cells are still under development, especially in the field of viral infections. These models can retain the unique immune memory of the donor, making them suitable for the study of correlates of protection upon natural infection or vaccination. Here, we will review some of these models and how they have been applied to virology research. Moreover, the future applications and the potential of these models to design therapies against human viral infections are discussed.

Characterization of Developmental Trajectories of Dendritic Cell Hematopoiesis Through Single-Cell RNA Sequencing Methods

Single-cell technologies have become valuable tools to trace dendritic cell differentiation trajectories. Here, we illustrate the workflow used for processing of mouse bone marrow for single-cell RNA sequencing and trajectory analyses, as done in Dress et al. (Nat Immunol 20:852-864, 2019). This short methodology is presented as a starting point for researchers just beginning to dive into the complex field of dendritic cell ontogeny and cellular development trajectory analyses.

CCR4 plays a pivotal role in Th17 cell recruitment and expansion in a mouse model of rheumatoid arthritis

T helper 17 (Th17) cells express CC chemokine receptor 4 (CCR4) and secrete cytokines such as interleukin-17A (IL-17A) and granulocyte macrophage colony-stimulating factor (GM-CSF), while dendritic cells (DCs) produce CC chemokine ligand 22 (CCL22), a CCR4 ligand, upon stimulation with GM-CSF. Th17 cells are known to play a critical role in the pathogenesis of rheumatoid arthritis (RA). CCL22 has also been shown to be up-regulated in the synovial tissues of RA patients. Here, we investigated the role of CCR4 in collagen-induced arthritis (CIA), a mouse model of RA. DBA/1J mice efficiently developed CIA as shown by erythema, paw swelling, joint rigidity, and joint destruction. Th17 cells were increased in the arthritic joints and regional lymph nodes (LNs) of CIA mice. A fraction of Th17 cells were also shown to produce GM-CSF. On the other hand, we observed no significant increases of Th2 cells or Treg cells, the T cell subsets also known to express CCR4, in these tissues. We further observed clusters of CCR4-expressing memory Th17 cells and CCL22-producing DCs in the regional LNs of CIA mice, supporting the role of the CCR4-CCL22 axis in the expansion of Th17 cells in the regional LNs. Compound 22, a CCR4 inhibitor, ameliorated the disease severity with reduction of Th17 cells in the arthritic joints and regional LNs and Th17-DC clusters in the regional LNs. We further confirmed that CCR4-deficient mice in the C57BL/6J background were highly resistant to CIA induction compared with wild-type mice. Collectively, CCR4 contributes to the pathogenesis of CIA and may thus represent a new therapeutic target for RA.

Dendritic cells generated from induced pluripotent stem cells and by direct reprogramming of somatic cells

Novel and exciting avenues allow generating dendritic cells (DC) by reprogramming of somatic cells. DC are obtained from induced pluripotent stem cells (iPS cells), referred to as ipDC, and by direct reprogramming of cells toward DC, referred to as induced DC (iDC). iPS cells represent pluripotent stem cells generated by reprogramming of somatic cells and can differentiate into all cell types of the body, including DC. This makes iPS cells and ipDC derived thereof useful for studying various DC subsets, acquiring high cell numbers for research and clinical use, or applying genome editing to generate DC with wanted properties. Thereby, ipDC overcome limitations in specific DC subsets, which are only found in low abundance in blood or lymphoid organs. iDC are generated by direct reprogramming of somatic cells with a specific set of transcription factors and offer an avenue to obtain DC without a pluripotent cell intermediate. ipDC and iDC retain patient and disease-specific mutations and this opens new perspectives for studying DC in disease. This review summarizes the current techniques used to generate ipDC and iDC, and the types and functionality of the DC generated.

Determining factors associated with the prevalence of knowledge, attitude, and practice in seeking skilled maternal healthcare services among women in a remote area of Gesha district

Background

Skilled health care is essential for the mother's and newborn's health and well-being during pregnancy, labor, and the postpartum period. This study aimed to analyze women's knowledge, attitudes, and practices while requesting competent assistance for maternity healthcare in Gesha District, Southwest Region of Ethiopia.

Methods

A community-based cross-sectional study design was conducted from September 20, 2021 to October 19, 2021. A total of 424 mothers participated in this study and a systematic sampling technique was used to select the respondents. The data were collected using a pretested and structured questionnaire. Statistical software SPSS-20 and R-4.1.2 were used to enter and analyze the data respectively. The factors associated with the prevalence of Knowledge, Attitude, and Practice in seeking Skilled Maternal Healthcare Services were identified using descriptive analysis and a binary logistic regression model.

Results

This study result revealed that the overall proportions of good knowledge, positive attitude, and good practice in seeking skilled maternal health care services were 39.15%, 37.5%, and 34.67% respectively. Estimated odds of having knowledge, attitude, and practice were as follows: for having age between 20–24 years at first pregnancy 1.859, 1.86, and 1.799; having a plan for pregnancy 2.74,2.315 and 2.579; mothers attended elementary education 2.337, 2.565 and 3.312; having maternal age 20–24 years 4.336,4.989 and 5.870; maternal age 25–29 years 2.917, 3.794 and 4.017; maternal age 35–49 years 2.837, 2.991 and 3.412; having husbands who had attended elementary education level 2.736, 2.542 and 2.134; secondary and above education 3.464, 3.360 and 2.508; rich mothers 2.261, 1.995 and 2.452; having antenatal care 4 times and above 2.606, 2.570, 2.682; having transportation access 1.921, 1.956 and 2.404; having media access 1.979, 2.171 and 2.715 respectively. The odds of having attitude and practice respectively were as follows: married 1.762, and 2.208; having medium wealth index 1.933 and 2.424. The odds of having previous pregnancy complications was 2.147 which significantly affect the practice of seeking skilled maternal care assistance.

Conclusions

This study discovered that the study participants' knowledge, attitude, and practice of skilled maternal health care are low. Associated factors included age at first pregnancy, planned pregnancy, maternal education level, husband’s education level, maternal age, antenatal care service visits, transport access, and access to media were found to significantly affect the knowledge, attitude, and practice of the respondents in seeking skilled maternal care assistance in common. The household wealth index was also associated with attitude. Pregnancy complications, current marital status, and household wealth index also significantly affect the practice of seeking skilled maternal care assistance. As a result of the findings, initiatives to increase women's knowledge, attitudes, and use of expert maternal health services in the research area are needed for women residing in rural areas.

Dendritic cell-based vaccine: the state-of-the-art vaccine platform for COVID-19 management

INTRODUCTION

A correlation between new coronaviruses and host immunity, as well as the role of defective immune function in host response, would be extremely helpful in understanding coronavirus disease (COVID-19) pathogenicity, and a coherent structure of treatments and vaccines. As existing vaccines may be inadequate for new viral variants emerging in various regions of the world, it is a vital requirement for fresh and effective therapeutic alternatives.

AREA COVERED

Immunotherapy may give a viable protective option for COVID-19, a disease that is currently a big burden on global health and economic systems. Herein, we have outlined three dendritic cell (DC)-based vaccines for COVID-19 which are in human clinical trials and have shown encouraging outcomes.

EXPERT OPINION

With existing knowledge of the virus, and the nature of DC, DC-based vaccines may be proven to be effective in inducing long-lasting protective immunity, especially T cell responses.

Transfection by Electroporation of Cancer and Primary Cells Using Nanosecond and Microsecond Electric Fields

Gene transfer into primary immune cells as well as into cell lines is essential for scientific and therapeutical applications. One of the methods used for gene transfer is electroporation (EP). EP is a method where a pulsed electric field (PEF) causes a highly transient permeability of the targeted cell membrane. In this work, we present the electrotransfection of CHO-K1, 4T1 cell lines, and primary murine DCs with detectable protein-encoding plasmids in the sub-microsecond range. Microsecond (µs)- and nanosecond (ns)-range pulsed electric field transfection protocols were used. The efficiency of electrotransfection was evaluated using green fluorescent protein (GFP)-encoding plasmids (4.7 kbp; p-EGFP-N1) and plasmids expressing a firefly luciferase and red fluorescent protein (tdTomato) (8.5 kbp; pcDNA3.1(+)/Luc2 = tdT)). It was shown that the used nsPEFs protocol (7 kV/cm × 300 ns × 100, 1 MHz) ensured a better transfection efficiency than µsPEFs (1.2 kV/cm × 100 µs × 8, 1 Hz). Plasmid size and concentration had a strong impact on the cell transfection efficiency too. We also showed that there were no significant differences in transfection efficiency between immature and mature DCs. Finally, the nsPEF protocols were successfully applied for the stable transfection of the CHO-K1 cell line with the linearized pcDNA3.1(+)/Luc2 = tdT plasmid. The results of the study are applicable in gene therapy and DNA vaccination studies for the derivation of optimal electrotransfection conditions.

Brain Functional Alteration at Different Stages of Neuropathic Pain With Allodynia and Emotional Disorders

Neuropathic pain (NeuP), a challenging medical condition, has been suggested by neuroimaging studies to be associated with abnormalities of neural activities in some brain regions. However, aberrancies in brain functional alterations underlying the sensory-discriminative abnormalities and negative emotions in the setting of NeuP remain unexplored. Here, we aimed to investigate the functional alterations in neural activity relevant to pain as well as pain-related depressive-like and anxiety-like behaviors in NeuP by combining amplitude of low frequency fluctuation (ALFF) and degree centrality (DC) analyses methods based on resting-state functional magnetic resonance imaging (rs-fMRI). A rat model of NeuP was established via chronic constriction injury (CCI) of the sciatic nerve. Results revealed that the robust mechanical allodynia occurred early and persisted throughout the entire observational period. Depressive and anxiety-like behaviors did not appear until 4 weeks after injury. When the maximum allodynia was apparent early, CCI rats exhibited decreased ALFF and DC values in the left somatosensory and nucleus accumbens shell (ACbSh), respectively, as compared with sham rats. Both values were significantly positively correlated with mechanical withdrawal thresholds (MWT). At 4 weeks post-CCI, negative emotional states were apparent and CCI rats were noted to exhibit increased ALFF values in the left somatosensory and medial prefrontal cortex (mPFC) as well as increased DC values in the right motor cortex, as compared with sham rats. At 4 weeks post-CCI, ALFF values in the left somatosensory cortex and DC values in the right motor cortex were noted to negatively correlate with MWT and exhibition of anxiety-like behavior on an open-field test (OFT); values were found to positively correlate with the exhibition of depressive-like behavior on forced swimming test (FST). The mPFC ALFF values were found to negatively correlate with the exhibition of anxiety-like behavior on OFT and positively correlate with the exhibition of depressive-like behavior on FST. Our findings detail characteristic alterations of neural activity patterns induced by chronic NeuP and underscore the important role of the left somatosensory cortex, as well as its related networks, in the mediation of subsequent emotional dysregulation due to NeuP.

The role of antigen-presenting cells in the pathogenesis of COVID-19

Coronavirus Disease 2019 (COVID-19) is one of the three lethal coronavirus outbreaks in the recent two decades and a serious threat to global health all over the world. The principal feature of the COVID-19 infection is the so-called "cytokine storm" exaggerated molecular response to virus distribution, which plays massive tissue and organ injury roles. Immunological treatments, including monoclonal antibodies and vaccines, have been suggested as the main approaches in treating and preventing this disease. Therefore, a proper investigation of the roles of antigen-presenting cells (APCs) in the aforementioned immunological responses appears essential. The present review will provide detailed information about APCs' role in the infection and pathogenesis of SARS-CoV-2 and the effect of monoclonal antibodies in diagnosis and treatment.

PKC agonism restricts innate immune suppression, promotes antigen cross-presentation and synergizes with agonistic CD40 antibody therapy to activate CD8+ T cells in breast cancer

Myeloid-derived suppressor cells (MDSCs) are an immature innate cell population that expands in pathological conditions such as cancer and suppresses T cells via production of immunosuppressive factors. Conversely, efficient cytotoxic T cell priming is dependent on the ability of antigen-presenting cells (APCs) to cross-present tumor antigens to CD8⁺ T cells, a process that requires a specific subtype of dendritic cells (DCs) called conventional DC1 (cDC1) which are often dysfunctional in cancer. One way to activate cDC1 is ligation of CD40 which is abundantly expressed by myeloid cells and its agonism leads to myeloid cell activation. Thus, targeting MDSCs while simultaneously expanding cross-presenting DCs represents a promising strategy that, when combined with agonistic CD40, may result in long-lasting protective immunity. In this study, we investigated the effect of PKC agonists PEP005 and prostratin on MDSC expansion, differentiation, and recruitment to the tumor microenvironment. Our findings demonstrate that PKC agonists decreased MDSC expansion from hematopoietic progenitors and induced M-MDSC differentiation to an APC-like phenotype that expresses cDC1-related markers via activation of the p38 mitogen-activated protein kinase (MAPK) pathway. Simultaneously, PKC agonists favored cDC1 expansion at the expense of cDC2 and plasmacytoid DCs (pDC). Functionally, PKC agonists blunted MDSC suppressive activity and enhanced MDSC cross-priming capacity both in vitro and in vivo. Finally, combination of PKC agonism with agonistic CD40 mAb resulted in a marked reduction in tumor growth with a significant increase in intratumoral activated CD8⁺ T cells and tissue-resident memory CD8⁺ T cells in a syngeneic breast cancer mouse model. In sum, this work proposes a novel promising strategy to simultaneously target MDSCs and promote APC function that may have highly impactful clinical relevance in cancer patients.

Type I conventional dendritic cells relate to disease severity in virus-induced asthma exacerbations

RATIONALE

Rhinoviruses are the major precipitant of asthma exacerbations and individuals with asthma experience more severe/prolonged rhinovirus infections. Concurrent viral infection and allergen exposure synergistically increase exacerbation risk. Although dendritic cells orchestrate immune responses to both virus and allergen, little is known about their role in viral asthma exacerbations.

OBJECTIVES

To characterize dendritic cell populations present in the lower airways, and to assess whether their numbers are altered in asthma compared to healthy subjects prior to infection and during rhinovirus-16 infection.

METHODS

Moderately-severe atopic asthmatic patients and healthy controls were experimentally infected with rhinovirus-16. Bronchoalveolar lavage was collected at baseline, day 3 and day 8 post infection and dendritic cells isolated using fluorescence activated cell sorting.

MEASUREMENTS AND MAIN RESULTS

Numbers of type I conventional dendritic cells, which cross prime CD8⁺ T helper cells and produce innate interferons, were significantly reduced in the lower airways of asthma patients compared to healthy controls at baseline. This reduction was associated serum IgE at baseline and with reduced numbers of CD8⁺ T helper cells and with increased viral replication, airway eosinophils and reduced lung function during infection. IgE receptor expression on lower airway plasmacytoid dendritic cells was significantly increased in asthma, consistent with a reduced capacity to produce innate interferons.

CONCLUSIONS

Reduced numbers of anti-viral type I conventional dendritic cells in asthma are associated with adverse outcomes during rhinovirus infection. This, with increased FcεR1α expression on lower airway plasmacytoid DCs could mediate the more permissive respiratory viral infection observed in asthma patients.

Circular RNA circHIPK3 is downregulated in diabetic cardiomyopathy and overexpression of circHIPK3 suppresses PTEN to protect cardiomyocytes from high glucose-induced cell apoptosis

It has been reported that circHIPK3 can be downregulated by high glucose, suggesting its potential involvement in diabetes and diabetic complications. This study aimed to explore the role of circHIPK3 in diabetic cardiomyopathy (DC). PTEN is a kind of tumor suppressor gene, which is very commonly lost in human cancer. We detected the expression of circHIPK3 and PTEN in plasma samples from DC patients, diabetic patients without complications diabetes mellitus (DM) and health controls by RT-qPCR and ELISA. In vitro cell experiment, AC16 cells (cardiomyocytes) were treated with high glucose, followed by expression analysis of circHIPK3 and PTEN mRNA by RT-qPCR. CircHIPK3 or PTEN expression vector were used to overexpress circHIPK3 and PTEN in AC16 cells to explore the relationship between them. The role of circHIPK3 and PTEN in regulating the apoptosis of AC16 cells was analyzed by cell apoptosis assay. The result showed that CircHIPK3 was downregulated in diabetes and further downregulated in DC. In AC16 cells, high glucose treatment decreased the expression levels of circHIPK3. Across DC samples, the expression of circHIPK3 was inversely correlated with PTEN. In AC16 cells, overexpression of circHIPK3 decreased the expression levels of PTEN. CircHIPK3 may suppress AC16 cell apoptosis induced by high glucose and inhibited the role of PTEN in cell apoptosis. Therefore, circHIPK3 may downregulate PTEN to protect cardiomyocytes from high glucose-induced cell apoptosis.

Functional Reorganization After Four-Week Brain-Computer Interface-Controlled Supernumerary Robotic Finger Training: A Pilot Study of Longitudinal Resting-State fMRI

Humans have long been fascinated by the opportunities afforded through motor augmentation provided by the supernumerary robotic fingers (SRFs) and limbs (SRLs). However, the neuroplasticity mechanism induced by the motor augmentation equipment still needs further investigation. This study focused on the resting-state brain functional reorganization during longitudinal brain-computer interface (BCI)-controlled SRF training in using the fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and degree centrality (DC) metrics. Ten right-handed subjects were enrolled for 4 weeks of BCI-controlled SRF training. The behavioral data and the neurological changes were recorded at baseline, training for 2 weeks, training for 4 weeks immediately after, and 2 weeks after the end of training. One-way repeated-measure ANOVA was used to investigate long-term motor improvement [F(2.805,25.24) = 43.94, p < 0.0001] and neurological changes. The fALFF values were significantly modulated in Cerebelum_6_R and correlated with motor function improvement (r = 0.6887, p < 0.0402) from t0 to t2. Besides, Cerebelum_9_R and Vermis_3 were also significantly modulated and showed different trends in longitudinal SRF training in using ReHo metric. At the same time, ReHo values that changed from t0 to t1 in Vermis_3 was significantly correlated with motor function improvement (r = 0.7038, p < 0.0344). We conclude that the compensation and suppression mechanism of the cerebellum existed during BCI-controlled SRF training, and this current result provided evidence to the neuroplasticity mechanism brought by the BCI-controlled motor-augmentation devices.

Abnormal Degree Centrality in Children with Low-Function Autism Spectrum Disorders: A Sleeping-State Functional Magnetic Resonance Imaging Study

PURPOSE

This study used the graph-theory approach, degree centrality (DC) to analyze whole-brain functional networks at the voxel level in children with ASD, and investigated whether DC changes were correlated with any clinical variables in ASD children.

METHODS

The current study included 86 children with ASD and 54 matched healthy subjects Aged 2-5.5 years. Next, chloral hydrate induced sleeping-state functional magnetic resonance imaging (ss-fMRI) datasets were acquired from these ASD and healthy subjects. For a given voxel, the DC was calculated by calculating the number of functional connections with significantly positive correlations at the individual level. Group differences were tested using two-sample t-tests (p < 0.01, AlphaSim corrected). Finally, relationships between abnormal DCs and clinical variables were investigated via Pearson's correlation analysis.

RESULTS

Children with ASD exhibited low DC values in the right middle frontal gyrus (MFG) (p < 0.01, AlphaSim corrected). Furthermore, significantly negative correlations were established between the decreased average DC values within the right MFG in ASD children and the total ABC scores, as well as with two ABC subscales measuring highly relevant impairments in ASD (ie, stereotypes and object-use behaviors and difficulties in language).

CONCLUSION

Taken together, the results of our ss-fMRI study suggest that abnormal DC may represent an important contribution to elucidation of the neuropathophysiological mechanisms of preschoolers with ASD.

HIV-1 trans-Infection Mediated by DCs: The Tip of the Iceberg of Cell-to-Cell Viral Transmission

HIV-1 cell-to-cell transmission is key for an effective viral replication that evades immunity. This highly infectious mechanism is orchestrated by different cellular targets that utilize a wide variety of processes to efficiently transfer HIV-1 particles. Dendritic cells (DCs) are the most potent antigen presenting cells that initiate antiviral immune responses, but are also the cells with highest capacity to transfer HIV-1. This mechanism, known as trans-infection, relies on the capacity of DCs to capture HIV-1 particles via lectin receptors such as the sialic acid-binding I-type lectin Siglec-1/CD169. The discovery of the molecular interaction of Siglec-1 with sialylated lipids exposed on HIV-1 membranes has enlightened how this receptor can bind to several enveloped viruses. The outcome of these interactions can either mount effective immune responses, boost the productive infection of DCs and favour innate sensing, or fuel viral transmission via trans-infection. Here we review these scenarios focusing on HIV-1 and other enveloped viruses such as Ebola virus or SARS-CoV-2.

Donor Chimerism Study by Single Nucleotide Polymorphism using SYBR green based Real Time PCR

Objective:

To optimize and evaluate a real time PCR of Single Nucleotide Polymorphism by SYBR Green method for detection of donor chimerism after haematopoietic stem cell transplantation.

Methods:

This descriptive study was conducted at Genetic Resource Centre (GRC) Lab Rawalpindi from Oct 2017 - Dec 2019. A total of twenty patients of post haematopoietic stem cell transplant with various haematological disorders were studied to see the status of donor chimerism by using SNP real time PCR using SYBR Green method and short tandem repeat PCR. These patients had undergone allogeneic HSCT from HLA-matched sibling donors at Pakistan Institute of Medical Science and Armed Forces Bone Marrow Transplant Centre.

Results:

Real time PCR using SYBR Green was able to detect significant amount of chimerism in all 20 patients having undergone HSCT. Regarding precision of the real time PCR assay the mean value of donor chimerism was 94.1% (SD 3.96) and by STR PCR it was 95.1% (SD 1.41). The assay was found to be sensitive with a detection limit of <1%.

Conclusion:

Our results demonstrate that SNP analysis by SYBR Green real time PCR may be used for the evaluation of chimerism status in patients having undergone HSCT with a sensitivity of <1%. Hence donor chimerism by this sensitive method can be used in monitoring of chimerism in post-transplant patients with various haematological disorders.

Aluminum in Bottom Sediments of the Lower Silesian Rivers Supplying Dam Reservoirs vs. Selected Chemical Parameters

The study was carried out on sediments collected from three rivers: Nysa Szalona, Strzegomka and Bystrzyca flowing in southwestern Poland. The content of Al in sediments and in bottom water was determined in relation to chemical conditions. The study was carried out in a four-year cycle, during spring and autumn. The aim of the study was to determine the level and accumulation of aluminum in sediments of rivers supplying dam reservoirs storing water for consumption. The sediments studied were mineral in nature, with neutral pH and moderate sulfate content. The level of Al and heavy metals in the sediments was the highest in the Nysa Szalona River and the lowest in the Strzegomka River, which was also evident in the concentration factor (CF). In terms of season, higher Al contents were recorded in sediments in autumn than in spring, which was also reflected in the concentration factor (CF). Along the course of the river, a gradual decrease in Al levels was observed in successive tributaries in the Nysa Szalona and Strzegomka Rivers, while there was no apparent regularity for the Bystrzyca. Against this background, a comparison of extreme sites below the springs and at the reservoir outlet shows that values were higher in the Nysa Szalona below the springs, and lower in the Strzegomka and Bystrzyca below the reservoir outlet. The general picture of Al and heavy metal loading of the studied sediments shows the lowest loading for the Strzegomka, only the enrichment factor (EF) was the lowest for the Nysa Szalona: metal pollution index (MPI)-S < B < NS, contamination factor (C_f)-S < B < NS, degree of contamination (DC)-S < NS < B, EF-NS < B < S, geoaccumulation index (I_geo)-S < B < NS, CF-S < NS < B. There was no effect of catchment size and river length on Al levels in sediments.

Berberine inhibits dendritic cells differentiation in DSS-induced colitis by promoting Bacteroides fragilis

BACKGROUNDS

Berberine (BBR), a compound long used in traditional Chinese medicine, has been reported to have therapeutic effects in treating ulcerative colitis (UC), attributed to its anti-inflammatory properties and restorative potential of tight junctions (TJs). However, the mechanism by which BBR affects intestinal bacteria and immunity is still unclear.

METHODS

This study investigated the effects of BBR on intestinal bacteria and the inflammatory response in dextran sulfate sodium (DSS)-induced colitis mice. Immunohistochemistry (IHC) and electron microscopy were used to detect intestinal TJs. Microflora analysis was used to screen for bacteria regulated by BBR.

RESULTS

The results showed that BBR had increased colonic epithelium zonula occludens proteins-1 (ZO-1) and occludin expression and reduced T-helper 17/T regulatory ratio in DSS-induced mice. Mechanically, BBR eliminated DSS-induced intestinal flora disturbances in mice, particularly increased Bacteroides fragilis (B. fragilis) in vivo and in vitro. B. fragilis decreased the interleukin-6 induced by dendritic cells through some heat-resistant component rather than nucleic acids or proteins.

CONCLUSIONS

Overall, these data suggest that BBR had a moderating effect on DSS-induced colitis. This compound may regulate intestinal immune cell differentiation by affecting the growth of B. fragilis, providing new insights into the potential application of BBR in UC.

Six-Color Confocal Immunofluorescence Microscopy with 4-Laser Lines

Confocal immunofluorescence microscopy is an advanced imaging technique routinely applied in the laboratory and clinics. Histological analyses are performed from tissue material. In general, a single fluorochrome per laser is employed, limiting simultaneous analysis to four antigens in one staining with a conventional 4-laser line microscope. Here, we describe a protocol for combining fluorochromes with the same excitation but different emission properties that allows for the analysis of six different antigens in confocal immunofluorescence microscopy with a conventional 4-laser line microscope. The proposed multiplexed method permits the identification and characterization of complex cell populations in rare tissue material.

IL-13Rα2 Regulates the IL-13/IFN-γ Balance during Innate Lymphoid Cell and Dendritic Cell Responses to Pox Viral Vector-Based Vaccination

We have shown that manipulation of IL-13 and STAT6 signaling at the vaccination site can lead to different innate lymphoid cell (ILC)/dendritic cell (DC) recruitment, resulting in high avidity/poly-functional T cells and effective antibody differentiation. Here we show that permanent versus transient blockage of IL-13 and STAT6 at the vaccination site can lead to unique ILC-derived IL-13 and IFN-γ profiles, and differential IL-13Rα2, type I and II IL-4 receptor regulation on ILC. Specifically, STAT6-/- BALB/c mice given fowl pox virus (FPV) expressing HIV antigens induced elevated ST2/IL-33R+ ILC2-derived IL-13 and reduced NKp46+/- ILC1/ILC3-derived IFN-γ expression, whilst the opposite (reduced IL-13 and elevated IFN-γ expression) was observed during transient inhibition of STAT6 signaling in wild type BALB/c mice given FPV-HIV-IL-4R antagonist vaccination. Interestingly, disruption/inhibition of STAT6 signaling considerably impacted IL-13Rα2 expression by ST2/IL-33R+ ILC2 and NKp46- ILC1/ILC3, unlike direct IL-13 inhibition. Consistently with our previous findings, this further indicated that inhibition of STAT6 most likely promoted IL-13 regulation via IL-13Rα2. Moreover, the elevated ST2/IL-33R+ IL-13Rα2+ lung ILC2, 24 h post FPV-HIV-IL-4R antagonist vaccination was also suggestive of an autocrine regulation of ILC2-derived IL-13 and IL-13Rα2, under certain conditions. Knowing that IL-13 can modulate IFN-γ expression, the elevated expression of IFN-γR on lung ST2/IL-33R+ ILC2 provoked the notion that there could also be inter-regulation of lung ILC2-derived IL-13 and NKp46- ILC1/ILC3-derived IFN-γ via their respective receptors (IFN-γR and IL-13Rα2) at the lung mucosae early stages of vaccination. Intriguingly, under different IL-13 conditions differential regulation of IL-13/IL-13Rα2 on lung DC was also observed. Collectively these findings further substantiated that IL-13 is the master regulator of, not only DC, but also different ILC subsets at early stages of viral vector vaccination, and responsible for shaping the downstream adaptive immune outcomes. Thus, thoughtful selection of vaccine strategies/adjuvants that can manipulate IL-13Rα2, and STAT6 signaling at the ILC/DC level may prove useful in designing more efficacious vaccines against different/chronic pathogens.

siRNA-based identification of IBD-related targets in human monocyte-derived dendritic cells

Inflammatory bowel disease (IBD) is thought to be caused by an aberrant host response to the commensal enteric flora in genetically susceptible individuals. Dendritic cells (DCs) play a key role in the regulation of this response as they sample gut commensals. In healthy individuals DCs actively contribute to tolerance upon recognition of these resident bacteria, whereas in individuals with IBD, DCs will initiate an inflammatory response. To mimic the disease response in vitro, human monocyte-derived DCs were matured with E. coli causing the cells to produce high levels of the pro-inflammatory cytokine IL-12/IL-23p40 (p40) and low levels of the anti-inflammatory cytokine IL-10. A siRNA-based screening assay was developed and screened to identify potential therapeutic targets that shift this balance towards an immunosuppressive state with lower levels of p40 and higher levels of IL-10. The screening assay was optimized and quality controlled using non-targeting controls and positive control siRNAs targeting IL12B and TLR4 transcripts. In the primary screen, smartpool siRNAs were screened for reduction in p40 expression, induction of IL-10 levels, or increase in IL-10:p40 ratios without affecting cell viability. All potential targets were taken forward into a confirmation screen in a different DC donor in which four individual siRNAs per target were screened. At least two siRNAs per target should have an effect to be considered a valid target. This screen resulted in a concise list of ten genes, of which their role in DC maturation is currently being investigated.

Targeting Innate Immunity to Combat Cutaneous Stress: The Vitiligo Perspective

Multiple factors are involved in the process leading to melanocyte loss in vitiligo including environmental triggers, genetic polymorphisms, metabolic alterations, and autoimmunity. This review aims to highlight current knowledge on how danger signals released by stressed epidermal cells in a predisposed patient can trigger the innate immune system and initiate a cascade of events leading to an autoreactive immune response, ultimately contributing to melanocyte disappearance in vitiligo. We will explore the genetic data available, the specific role of damage-associated-molecular patterns, and pattern-recognition receptors, as well as the cellular players involved in the innate immune response. Finally, the relevance of therapeutic strategies targeting this pathway to improve this inflammatory and autoimmune condition is also discussed.

Autophagy regulates long-term cross-presentation by murine dendritic cells

Autophagy has been reported to be involved in supporting antigen cross-presentation by dendritic cells (DCs). We have shown that DCs have the ability to store antigen for a prolonged time in endolysosomal compartments and thereby sustain MHCI antigen cross-presentation to CD8+ T cells. In the current study, we investigated the role of autophagy in long-term antigen presentation. We show that the autophagy machinery has a negative impact on storage of antigen in DCs. Atg5-/- DCs which are deficient in autophagy or DCs treated with common autophagy inhibitors showed enhanced antigen storage and antigen cross-presentation. This augmented antigen cross-presentation effect is independent of altered proteasome enzyme activity or MHCI surface expression on DCs. We visualized that the storage compartments are in close proximity to LC3 positive autophagosomes. Our results indicate that autophagosomes disrupt antigen storage in DCs and thereby regulate long-term MHCI cross-presentation.

Co-delivery of PSMA antigen epitope and mGM-CSF with a cholera toxin-like chimeric protein suppressed prostate tumor growth via activating dendritic cells and promoting CTL responses

Subunit vaccines derived from tumor antigens play a role in tumor therapy because of their unique advantages. However, because of the weak immunogenicity of peptides in subunit vaccines, it is difficult to trigger an effective cytotoxic T lymphocyte (CTL) response, which is critical for cancer therapy. A requirement for the activation of CTL cells by exogenous antigens is the stimulation of antigen presenting cells (APC) with the help of adjuvants and cross-presentation to T lymphocytes. Standard nonconjugated adjuvant-peptide mixtures do not ensure co-targeting of the antigen and the adjuvant to the same APC, which limits the effects of adjuvants. In this study, a fusion protein consisting of murine granulocyte-macrophage colony stimulating factor (mGM-CSF) fused with CTA2 (A2 subunit of cholera toxin) was generated and assembled with CTB-PSMA624-632 (prostate specific membrane antigen (PSMA) peptide 624-632 fused to CTB) to obtain a cholera toxin-like protein. The chimeric protein retained the biological activity of mGM-CSF and had stronger GM1 binding activity than (CTB-PSMA624-632)5. C57BL/6J mice immunized with the CT-like chimeric protein exhibited delayed tumor growth following challenge with human PSMA-EGFP-expressing RM-1 cells. Experiment results showed that the CT-like chimeric protein could induce the maturation of DC cells and improve CTL responses. Overall, these results indicate that the nasal administration of a CT-like chimeric protein vaccine results in the development of effective immunity against prostate tumor cells and might be useful for future clinical anti-tumoral applications.

SARS-CoV-2 Infection and Mitigation Efforts among Office Workers, Washington, DC, USA

Despite mitigation efforts, 2 coronavirus disease outbreaks were identified among office workers in Washington, DC. Moderate adherence to workplace mitigation efforts was reported in a serologic survey; activities outside of the workplace were associated with infection. Adherence to safety measures are critical for returning to work during the pandemic.

Chronic hepatitis C virus infection impairs natural killer cells-dendritic cells cross-talk: An in vitro culture study

To examine the cross-talk between NK cells and DCs in hepatitis C virus (HCV) infection, we isolated monocytes and NK cells from 20 chronic HCV patients and 20 healthy controls. Monocytes were used to generate immature DCs which were pulsed with HCV peptides (core, NS3-NS4, and NS5). Four different cocultures were carried out: E1, both DCs and NK cells were from a chronic HCV patient; E2, NK cells from a healthy control cocultured with DCs from a chronic HCV patient; E3, NK cells from a chronic HCV patient cocultured with DCs from a healthy control; and E4, both DCs and NK cells were from a healthy control. Using flow cytometry, we assessed the effect of these different cocultures on levels of maturation markers on DCs and levels of activation/inhibition markers on NK cells. Results showed that peptide-pulsed HCV DCs showed a maturation defect in the form of decreased HLA-DR, decreased CD86, and increased CD83 expression especially when cocultured with HCV NK. This was mainly due to core peptide pulsing and to a lesser extent due to NS5 pulsing, whereas there was no effect with NS3-NS4 pulsing. Alternatively, HCV NK cells upregulated both activation and inhibition markers especially when cocultured with healthy DCs. Compared with E2, E1 resulted in higher apoptosis of both NK cells and DCs with the percentage of NK apoptosis higher than that of DCs. Taken together, the data indicate that HCV infection impairs NK-DC cross-talk which may be a leading cause in viral persistence and chronicity.

Next-Generation Immunotherapies to Improve Anticancer Immunity

Checkpoint inhibitors are widely used immunotherapies for advanced cancer. Nonetheless, checkpoint inhibitors have a relatively low response rate, work in a limited range of cancers, and have some unignorable side effects. Checkpoint inhibitors aim to reinvigorate exhausted or suppressed T cells in the tumor microenvironment (TME). However, the TME contains various other immune cell subsets that interact to determine the fate of cytotoxic T cells. Activation of cytotoxic T cells is initiated by antigen cross-presentation of dendritic cells. Dendritic cells could also release chemokines and cytokines to recruit and foster T cells. B cells, another type of antigen-presenting cell, also foster T cells and can produce tumor-specific antibodies. Neutrophils, a granulocyte cell subset in the TME, impede the proliferation and activation of T cells. The TME also consists of cytotoxic innate natural killer cells, which kill tumor cells efficiently. Natural killer cells can eradicate major histocompatibility complex I-negative tumor cells, which escape cytotoxic T cell–mediated destruction. A thorough understanding of the immune mechanism of the TME, as reviewed here, will lead to further development of more powerful therapeutic strategies. We have also reviewed the clinical outcomes of patients treated with drugs targeting these immune cells to identify strategies for improvement and possible immunotherapy combinations.

JAK1/2 inhibition impairs the development and function of inflammatory dendritic epidermal cells in atopic dermatitis

BACKGROUND

Janus kinase (JAK) inhibitors are a new class of therapeutic compounds for dermatological diseases. In atopic dermatitis (AD), data of clinical phase III trials show rapid improvement of pruritus and significant reduction of inflammation within the first weeks with a favorable safety profile. However, their mode of action in AD is not fully understood.

OBJECTIVES

In our study, we investigate the effect of different JAK inhibitors on cell differentiation, phenotype, and function of inflammatory dendritic epidermal cells (IDECs).

METHODS

We analyzed the JAK expression in IDEC from ex vivo skin and in vitro generated IDECs using flow cytometry and PCR. Further, we studied in vitro the effect of different JAK inhibitors on IDEC cell differentiation, phenotype, and maturation.

RESULTS

IDECs express JAK1 and JAK2 ex vivo and in vitro. We found that JAK1 and JAK2 were upregulated during the differentiation from monocytes to IDECs. Conversely, JAK2 inhibition by ruxolitinib (JAK1/2 inhibitor) or BMS-911543 (JAK2 inhibitor) abrogated the differentiation from monocytes into IDECs. Differentiated IDECs can redifferentiate into a more monocyte-like phenotype in the presence of ruxolitinib or BMS-911543. Furthermore, we showed that concomitant inhibition of JAK1/2 rather than blocking JAK1 or JAK2 alone, impaired maturation and the release of proinflammatory cytokines on lipopolysaccharide stimulation.

CONCLUSIONS

Our results suggest that inhibition of JAK1/2 impairs IDEC differentiation and function. We provide new insight into the mode of action of JAK inhibitors in AD and highlight the role of JAK1/2 inhibitors for the treatment of patients with AD.

A Comprehensive Experimental Guide to Studying Cross-Presentation in Dendritic Cells In Vitro

Cross-presentation was first observed serendipitously in the 1970s. The importance of it was quickly realized and subsequently attracted great attention from immunologists. Since then, our knowledge of the ability of certain antigen presenting cells to internalize, process, and load exogenous antigens onto MHC-I molecules to cross-prime CD8+ T cells has increased significantly. Dendritic cells (DCs) are exceptional cross-presenters, thus making them a great tool to study cross-presentation but the relative rarity of DCs in circulation and in tissues makes it challenging to isolate sufficient numbers of cells to study this process in vitro. In this paper, we describe in detail two methods to culture DCs from bone-marrow progenitors and a method to expand the numbers of DCs present in vivo as a source of endogenous bona-fide cross-presenting DCs. We also describe methods to assess cross-presentation by DCs using the activation of primary CD8+ T cells as a readout. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Isolation of bone marrow progenitor cells Basic Protocol 2: In vitro differentiation of dendritic cells with GM-CSF Support Protocol 1: Preparation of conditioned medium from GM-CSF producing J558L cells Basic Protocol 3: In vitro differentiation of dendritic cells with Flt3L Support Protocol 2: Preparation of Flt3L containing medium from B16-Flt3L cells Basic Protocol 4: Expansion of cDC1s in vivo for use in ex vivo experiments Basic Protocol 5: Characterizing resting and activated dendritic cells Basic Protocol 6: Dendritic cell stimulation, antigenic cargo, and fixation Support Protocol 3: Preparation of model antigen coated microbeads Support Protocol 4: Preparation of apoptotic cells Support Protocol 5: Preparation of recombinant bacteria Basic Protocol 7: Immunocytochemistry immunofluorescence (ICC/IF) Support Protocol 6: Preparation of Alcian blue-coated coverslips Basic Protocol 8: CD8+ T cell activation to assess cross-presentation Support Protocol 7: Isolation and labeling of CD8+ T cells with CFSE.

PPARα Inhibition Overcomes Tumor-Derived Exosomal Lipid-Induced Dendritic Cell Dysfunction

Dendritic cells (DCs) orchestrate the initiation, programming, and regulation of anti-tumor immune responses. Emerging evidence indicates that the tumor microenvironment (TME) induces immune dysfunctional tumor-infiltrating DCs (TIDCs), characterized with both increased intracellular lipid content and mitochondrial respiration. The underlying mechanism, however, remains largely unclear. Here, we report that fatty acid-carrying tumor-derived exosomes (TDEs) induce immune dysfunctional DCs to promote immune evasion. Mechanistically, peroxisome proliferator activated receptor (PPAR) α responds to the fatty acids delivered by TDEs, resulting in excess lipid droplet biogenesis and enhanced fatty acid oxidation (FAO), culminating in a metabolic shift toward mitochondrial oxidative phosphorylation, which drives DC immune dysfunction. Genetic depletion or pharmacologic inhibition of PPARα effectively attenuates TDE-induced DC-based immune dysfunction and enhances the efficacy of immunotherapy. This work uncovers a role for TDE-mediated immune modulation in DCs and reveals that PPARα lies at the center of metabolic-immune regulation of DCs, suggesting a potential immunotherapeutic target.

Yin et al. reveal that tumor-derived exosomes (TDEs), as fatty acid carriers, induce a metabolic shift toward oxidative phosphorylation, driving DC immune dysfunction. Transcriptomic analysis identifies PPARα as the fatty acid sensor mediating the immunosuppressive effects of TDEs on DCs. PPARα blockade effectively restores DC function and enhances the efficacy of immunotherapy.

Feeding lactobacilli impacts lupus progression in (NZBxNZW)F1 lupus-prone mice by enhancing immunoregulation

Although the relationship between autoimmunity and microorganisms is complex, there is evidence that microorganisms can prevent the development of various autoimmune diseases. Lactobacilli are beneficial gut bacteria that play an important role in immune system development. The goals of this study were to assess the ability of three different strains of lactobacilli (L. casei B255, L. reuteri DSM 17509 and L. plantarum LP299v) to control lupus development/progression in (NZBxNZW)F1 (BWF1) lupus-prone mice before and after disease onset, and identify the mechanisms mediating protection. BWF1 mice fed with individual L. casei or L. reuteri before disease onset exhibited delayed lupus onset and increased survival, while feeding L. plantarum had little impact. In vitro treatment of BWF1 dendritic cells with individual lactobacilli strains upregulated IL-10 production to various extents, with L. casei being the most effective. The protection mediated by L. casei was associated with upregulation of B7-1 and B7-2 by antigen presenting cells, two costimulatory molecules important for regulatory T cell (Treg) induction. Moreover, feeding L. casei lead to increased percentages of CD4⁺Foxp3⁺ Tregs and IL10-producing T cells in the lymphoid organs of treated mice. More importantly, mice fed L. casei after disease onset remained stable for several months, i.e. exhibited delayed anti-nucleic acid production and kidney disease progression, and increased survival. Therefore, feeding lactobacilli appears to delay lupus progression possibly via mechanisms involving Treg induction and IL-10 production. Altogether, these data support the notion that ingestion of lactobacilli, with immunoregulatory properties, may be a viable strategy for controlling disease development and progression in patients with lupus, i.e. extending remission length and reducing flare frequency.

Tumor Arrests DN2 to DN3 Pro T Cell Transition and Promotes Its Conversion to Thymic Dendritic Cells by Reciprocally Regulating Notch1 and Ikaros Signaling

Tumor progression in the host leads to severe impairment of intrathymic T-cell differentiation/maturation, leading to the paralysis of cellular anti-tumor immunity. Such suppression manifests the erosion of CD4⁺CD8⁺ double-positive (DP) immature thymocytes and a gradual increase in CD4^-CD8^- double negative (DN) early T-cell progenitors. The impact of such changes on the T-cell progenitor pool in the context of cancer remains poorly investigated. Here, we show that tumor progression blocks the transition of Lin^-Thy1.2⁺CD25⁺CD44⁺c-Kit^lowDN2b to Lin^-Thy1.2⁺CD25⁺CD44^-c-Kit^-DN3 in T-cell maturation, instead leading to DN2-T-cell differentiation into dendritic cells (DC). We observed that thymic IL-10 expression is upregulated, particularly at cortico-medullary junctions (CMJ), under conditions of progressive disease, resulting in the termination of IL-10R^high DN2-T-cell maturation due to dysregulated expression of Notch1 and its target, CCR7 (thus restricting these cells to the CMJ). Intrathymic differentiation of T-cell precursors in IL-10^-/- mice and in vitro fetal thymic organ cultures revealed that IL-10 promotes the interaction between thymic stromal cells and Notch1^low DN2-T cells, thus facilitating these DN2-T cells to differentiate toward CD45⁺CD11c⁺MHC-II⁺ thymic DCs as a consequence of activating the Ikaros/IRF8 signaling axis. We conclude that a novel function of thymically-expressed IL-10 in the tumor-bearing host diverts T-cell differentiation toward a DC pathway, thus limiting the protective adaptive immune repertoire.

Potential of immunotherapies in the mediation of antileukemic responses for patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) - With a focus on Dendritic cells of leukemic origin (DCleu)

New (non-immunotherapeutic) treatment-strategies for AML/MDS-patients are under development. Dendritic cells (DCs) and 'leukemia-derived DC' (DC_leu) connect the innate and the adaptive immunesystem and (re-)activate it, in their capacity as professional antigen-presenting cells (APCs). They can be generated ex vivo from peripheral blood mononuclear cells (PBMNCs) or whole blood (WB), containing the -physiological-cellular/soluble microenvironment of individual patients using various DC/DC_leu-generating methods or (for WB) minimalized 'Kits', containing granulocyte-macrophage-colony-stimulating-factor (GM-CSF) and a second response-modifier. Proof for DC/DC_leu-mediated activation of the immune-system after T-cell-enriched mixed lymphocyte culture (MLC) is done by flowcytometry, demonstrating increased fractions of certain activated, leukemia-specific or antileukemic cell-subsets of the innate and the adaptive immune-system. Generation of DC/DC_leu is possible independent of patients' age, MHC-, mutation- or transplantation-status. In vivo-treatment of AML-/MDS-patients with blast-modulating, DC/DC_leu- inducing 'Kits' could contribute to create migratory DCs, as well as antileukemically reactivated and memory-mediating immune-cells, which patrol tissue and blood and could contribute to stabilizing disease or remissions.