Single-Cell Analyses Inform Mechanisms of Myeloid-Targeted Therapies in Colon Cancer.

Single-cell RNA sequencing (scRNA-seq) is a powerful tool for defining cellular diversity in tumors, but its application toward dissecting mechanisms underlying immune-modulating therapies is scarce. We performed scRNA-seq analyses on immune and stromal populations from colorectal cancer patients, identifying specific macrophage and conventional dendritic cell (cDC) subsets as key mediators of cellular cross-talk in the tumor microenvironment. Defining comparable myeloid populations in mouse tumors enabled characterization of their response to myeloid-targeted immunotherapy. Treatment with anti-CSF1R preferentially depleted macrophages with an inflammatory signature but spared macrophage populations that in mouse and human expresses pro-angiogenic/tumorigenic genes. Treatment with a CD40 agonist antibody preferentially activated a cDC population and increased Bhlhe40+ Th1-like cells and CD8+ memory T cells. Our comprehensive analysis of key myeloid subsets in human and mouse identifies critical cellular interactions regulating tumor immunity and defines mechanisms underlying myeloid-targeted immunotherapies currently undergoing clinical testing.

Transcriptional and Functional Analysis of CD1c+ Human Dendritic Cells Identifies a CD163+ Subset Priming CD8+CD103+ T Cells.

Dendritic cells (DCs) are antigen-presenting cells controlling T cell activation. In humans, the diversity, ontogeny, and functional capabilities of DC subsets are not fully understood. Here, we identified circulating CD88-CD1c+CD163+ DCs (called DC3s) as immediate precursors of inflammatory CD88-CD14+CD1c+CD163+FcεRI+ DCs. DC3s develop via a specific pathway activated by GM-CSF, independent of cDC-restricted (CDP) and monocyte-restricted (cMoP) progenitors. Like classical DCs but unlike monocytes, DC3s drove activation of naive T cells. In vitro, DC3s displayed a distinctive ability to prime CD8+ T cells expressing a tissue homing signature and the epithelial homing alpha-E integrin (CD103) through transforming growth factor ß (TGF-ß) signaling. In vivo, DC3s infiltrated luminal breast cancer primary tumors, and DC3 infiltration correlated positively with CD8+CD103+CD69+ tissue-resident memory T cells. Together, these findings define DC3s as a lineage of inflammatory DCs endowed with a strong potential to regulate tumor immunity.

Imaging dendritic cell functions.

Dendritic cells (DCs) are crucial for the appropriate initiation of adaptive immune responses. During inflammation, DCs capture antigens, mature, and migrate to lymphoid tissues to present foreign material to naïve T cells. These cells get activated and differentiate either into pathogen-specific cytotoxic CD8+ T cells that destroy infected cells or into CD4+ T helper cells that, among other effector functions, orchestrate antibody production by B cells. DC-mediated antigen presentation is equally important in non-inflammatory conditions. Here, DCs mediate induction of tolerance by presenting self-antigens or harmless environmental antigens and induce differentiation of regulatory T cells or inactivation of self-reactive immune cells. Detailed insights into the biology of DCs are, therefore, crucial for the development of novel vaccines as well as the prevention of autoimmune diseases. As in many other life science areas, our understanding of DC biology would be extremely restricted without bioimaging, a compilation of methods that visualize biological processes. Spatiotemporal tracking of DCs relies on various imaging tools, which not only enable insights into their positioning and migration within tissues or entire organs but also allow visualization of subcellular and molecular processes. This review aims to provide an overview of the imaging toolbox and to provide examples of diverse imaging techniques used to obtain fundamental insights into DC biology.

Detection of dendritic cell subsets in the tumor microenvironment by multiplex immunohistochemistry.

Dendritic cells (DCs) are essential in antitumor immunity. In humans, three main DC subsets are defined: two types of conventional DCs (cDC1s and cDC2s) and plasmacytoid DCs (pDCs). To study DC subsets in the tumor microenvironment (TME), it is important to correctly identify them in tumor tissues. Tumor-derived DCs are often analyzed in cell suspensions in which spatial information about DCs which can be important to determine their function within the TME is lost. Therefore, we developed the first standardized and optimized multiplex immunohistochemistry panel, simultaneously detecting cDC1s, cDC2s, and pDCs within their tissue context. We report on this panel's development, validation, and quantitative analysis. A multiplex immunohistochemistry panel consisting of CD1c, CD303, X-C motif chemokine receptor 1, CD14, CD19, a tumor marker, and DAPI was established. The ImmuNet machine learning pipeline was trained for the detection of DC subsets. The performance of ImmuNet was compared with conventional cell phenotyping software. Ultimately, frequencies of DC subsets within several tumors were defined. In conclusion, this panel provides a method to study cDC1s, cDC2s, and pDCs in the spatial context of the TME, which supports unraveling their specific roles in antitumor immunity.

Hepatitis C virus modified sE2F442NYT as an antigen in candidate vaccine facilitates human immune cell activation.

The rational selection of hepatitis C virus (HCV) vaccine antigen will aid in the prevention of future chronic liver disease burden and associated healthcare costs. We have previously shown that HCV E2 glycoprotein is not highly immunogenic, and the modification of E2 reduced CD81 binding and displayed altered cytokine and protective immune responses in vitro and in a surrogate mouse model. Here, we compared the influence of a parental and a modified sE2F442NYT glycoprotein region from HCV genotype 1a for the activation of peripheral blood mononuclear cell (PBMC)-derived dendritic cells (DCs), CD4+T cells, and B cells. Modified sE2F442NYT, when incubated with DCs, induced a higher number of CD86-positive cells. The sE2F442NYT or parental sE2 encapsulated as mRNA-lipid nanoparticle (sE2F442NYT mRNA-LNP) primed DCs co-cultured with autologous CD4+T cells did not induce CD25 or forkhead box P3 expression. PBMC-derived CD4+T cells treated with sE2F442NYT exhibited enhanced signal transducer and activator of transcription (Stat)1/Stat4 phosphorylation in response to anti-CD3/CD28 stimulation in comparison to parental sE2 treatment and facilitated isotype switching in B cells, leading to the generation of a broader subclass of antibodies. Cells treated with modified sE2F442NYT displayed an increase in activated Stat3 and extracellular signal-regulated kinase (ERK). Likewise, PBMC-derived naïve B cells upon in vitro stimulation with sE2F442NYT induced an increased proliferation, Stat3 and ERK activation, and protein kinase B (Akt) suppression. Thus, the modified sE2F442NYT antigen from HCV facilitates improved DC, CD4+T, and B cell activation compared to parental sE2 to better induce a robust protective immune response, supporting its selection as an HCV candidate vaccine antigen for preclinical and clinical HCV vaccine trials.IMPORTANCEThe nature of an enhanced immune response induced by sE2F442NYT will help in the selection of a broad cross-protective antigen from hepatitis C virus genotypes, and the inclusion of relatively conserved sE1 with sE2F442NYT may further strengthen the efficacy of the candidate vaccine in evaluating it for human use.

The role of dendritic cells in the instruction of helper T cells in the allergic march.

Allergy is a complex array of diseases influenced by innate and adaptive immunity, genetic polymorphisms, and environmental triggers. Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by barrier defects and immune dysregulation, sometimes leading to asthma and food allergies because of the atopic march. During atopic skin inflammation, Langerhans cells and dendritic cells (DCs) in the skin capture and deliver allergen information to local lymph nodes. DCs are essential immune sensors coordinating immune reactions by capturing and presenting antigens to T cells. In the context of allergic responses, DCs play a crucial role in instructing two types of helper T cells - type 2 helper T (Th2) cells and follicular helper T (TFH) cells - in allergic responses and IgE antibody responses. In skin sensitization, the differentiation and function of Th2 cells and TFH cells are influenced by skin-derived factors, including epithelial cytokines, chemokines, and signaling pathways to modify the function of migratory DCs and conventional DCs. In this review, we aim to understand the specific mechanisms involving DCs in allergic responses to provide insights into the pathogenesis of allergic diseases and potential therapeutic strategies.

SMART-lipid nanoparticles enabled mRNA vaccine elicits cross-reactive humoral responses against the omicron sub-variants.

The continual emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants has necessitated the development of broad cross-reactive vaccines. Recent findings suggest that enhanced antigen presentation could lead to cross-reactive humoral responses against the emerging variants. Toward enhancing the antigen presentation to dendritic cells (DCs), we developed a novel shikimoylated mannose receptor targeting lipid nanoparticle (SMART-LNP) system that could effectively deliver mRNAs into DCs. To improve the translation of mRNA, we developed spike domain-based trimeric S1 (TS1) mRNA with optimized codon sequence, base modification, and engineered 5' and 3' UTRs. In a mouse model, SMART-LNP-TS1 vaccine could elicit robust broad cross-reactive IgGs against Omicron sub-variants, and induced interferon-γ-producing T cells against SARS-CoV-2 virus compared with non-targeted LNP-TS1 vaccine. Further, T cells analysis revealed that SMART-LNP-TS1 vaccine induced long-lived memory T cell subsets, T helper 1 (Th1)-dominant and cytotoxic T cells immune responses against the SARS-CoV-2 virus. Importantly, SMART-LNP-TS1 vaccine produced strong Th1-predominant humoral and cellular immune responses. Overall, SMART-LNPs can be explored for precise antigenic mRNA delivery and robust immune responses. This platform technology can be explored further as a next-generation delivery system for mRNA-based immune therapies.

A comprehensive overview of diffuse correlation spectroscopy: theoretical framework, recent advances in hardware, analysis, and applications.

Diffuse correlation spectroscopy (DCS) is a powerful tool for assessing microvascular hemodynamic in deep tissues. Recent advances in sensors, lasers, and deep learning have further boosted the development of new DCS methods. However, newcomers might feel overwhelmed, not only by the already-complex DCS theoretical framework but also by the broad range of component options and system architectures. To facilitate new entry to this exciting field, we present a comprehensive review of DCS hardware architectures (continuous-wave, frequency-domain, and time-domain) and summarize corresponding theoretical models. Further, we discuss new applications of highly integrated silicon single-photon avalanche diode (SPAD) sensors in DCS, compare SPADs with existing sensors, and review other components (lasers, sensors, and correlators), as well as data analysis tools, including deep learning. Potential applications in medical diagnosis are discussed and an outlook for the future directions is provided, to offer effective guidance to embark on DCS research.

Specialized cis-Acting RNA Elements Balance Genome Cyclization to Ensure Efficient Replication of Yellow Fever Virus.

Genome cyclization is essential for viral RNA (vRNA) replication of the vertebrate-infecting flaviviruses, and yet its regulatory mechanisms are not fully understood. Yellow fever virus (YFV) is a notorious pathogenic flavivirus. Here, we demonstrated that a group of cis-acting RNA elements in YFV balance genome cyclization to govern efficient vRNA replication. It was shown that the downstream of the 5'-cyclization sequence hairpin (DCS-HP) is conserved in the YFV clade and is important for efficient YFV propagation. By using two different replicon systems, we found that the function of the DCS-HP is determined primarily by its secondary structure and, to a lesser extent, by its base-pair composition. By combining in vitro RNA binding and chemical probing assays, we found that the DCS-HP orchestrates the balance of genome cyclization through two different mechanisms, as follows: the DCS-HP assists the correct folding of the 5' end in a linear vRNA to promote genome cyclization, and it also limits the overstabilization of the circular form through a potential crowding effect, which is influenced by the size and shape of the DCS-HP structure. We also provided evidence that an A-rich sequence downstream of the DCS-HP enhances vRNA replication and contributes to the regulation of genome cyclization. Interestingly, diversified regulatory mechanisms of genome cyclization, involving both the downstream of the 5'-cyclization sequence (CS) and the upstream of the 3'-CS elements, were identified among different subgroups of the mosquito-borne flaviviruses. In summary, our work highlighted how YFV precisely controls the balance of genome cyclization to ensure viral replication. IMPORTANCE Yellow fever virus (YFV), the prototype of the Flavivirus genus, can cause devastating yellow fever disease. Although it is preventable by vaccination, there are still tens of thousands of yellow fever cases per year, and no approved antiviral medicine is available. However, the understandings about the regulatory mechanisms of YFV replication are obscure. In this study, by a combination of bioinformatics, reverse genetics, and biochemical approaches, it was shown that the downstream of the 5'-cyclization sequence hairpin (DCS-HP) promotes efficient YFV replication by modulating the conformational balance of viral RNA. Interestingly, we found specialized combinations for the downstream of the 5'-cyclization sequence (CS) and upstream of the 3'-CS elements in different groups of the mosquito-borne flaviviruses. Moreover, possible evolutionary relationships among the various downstream of the 5'-CS elements were implied. This work highlighted the complexity of RNA-based regulatory mechanisms in the flaviviruses and will facilitate the design of RNA structure-targeted antiviral therapies.

Changes in the innate immune response to SARS-CoV-2 with advancing age in humans.

BACKGROUND: Advancing age is a major risk factor for respiratory viral infections. The infections are often prolonged and difficult to resolve resulting hospitalizations and mortality. The recent COVID-19 pandemic has highlighted this as elderly subjects have emerged as vulnerable populations that display increased susceptibility and severity to SARS-CoV-2. There is an urgent need to identify the probable mechanisms underlying this to protect against future outbreaks of such nature. Innate immunity is the first line of defense against viruses and its decline impacts downstream immune responses. This is because dendritic cells (DCs) and macrophages are key cellular elements of the innate immune system that can sense and respond to viruses by producing inflammatory mediators and priming CD4 and CD8 T-cell responses. RESULTS: We investigated the changes in innate immune responses to SARS-CoV-2 as a function of age. Our results using human PBMCs from aged, middle-aged, and young subjects indicate that the activation of DCs and monocytes in response to SARS-CoV-2 is compromised with age. The impairment is most apparent in pDCs where both aged and middle-aged display reduced responses. The secretion of IL-29 that confers protection against respiratory viruses is also decreased in both aged and middle-aged subjects. In contrast, inflammatory mediators associated with severe COVID-19 including CXCL-8, TREM-1 are increased with age. This is also apparent in the gene expression data where pathways related host defense display an age dependent decrease with a concomitant increase in inflammatory pathways. Not only are the inflammatory pathways and mediators increased after stimulation with SARS-CoV-2 but also at homeostasis. In keeping with reduced DC activation, the induction of cytotoxic CD8 T cells is also impaired in aged subjects. However, the CD8 T cells from aged subjects display increased baseline activation in accordance with the enhanced baseline inflammation. CONCLUSIONS: Our results demonstrate a decline in protective anti-viral immune responses and increase in damaging inflammatory responses with age indicating that dysregulated innate immune responses play a significant role in the increased susceptibility of aged subjects to COVID-19. Furthermore, the dysregulation in immune responses develops early on as middle-aged demonstrate several of these changes.

The immun function of dendritic cells in SFTS patients.

OBJECTIVES: Severe fever with thrombocytopenia syndrome (SFTS) is a newly emerging infectious disease caused by a novel bunyavirus in which host immune system suppression is thought to be crucial in disease development. Dendritic cells (DCs) are professional antigen-presenting cells (APCs) critical for initiation and orchestration of the immune response. And it have been suggested that functionally impaired DCs may mediate the suppression of host-specific T-cell immune responses and thus facilitate viral persistence and disease progression.This study was designed to improve the in vitro culture method for DCs and investigate the different immunologic functions of DCs between SFTS patients and healthy people. METHODS: All confirmed SFTS patients (N = 10) were recruited from the Jinan Infectious Diseases Hospital in 2019; routine laboratory parameters were collected. The frequencies, phenotypes were analyzed by flow cytometry. And the levels of 8 cytokines in the cell culture supernatant were detected by flow cytometry. RESULTS: On day 8 of the incubation period, cells were harvested and analyzed by flow cytometry. There were significant differences in the rates of CD1a-, CD83-positive cells between SFTS patients and healthy people (all P < 0.05). The detection of 8 cytokines in the culture supernatant showed that the expressions of IFN-α and IFN-γ in the culture supernatant of DC cells in SFTS patients were lower than those in normal people (P < 0.05, P < 0.01). CONCLUSIONS: The present results indicate that DCs may be functionally impaired in SFTS. A decreased level of circulating mDCs was closely correlated with SFTS progression.

Major alterations in the mononuclear phagocyte landscape associated with COVID-19 severity.

Dendritic cells (DCs) and monocytes are crucial mediators of innate and adaptive immune responses during viral infection, but misdirected responses by these cells may contribute to immunopathology. Here, we performed high-dimensional flow cytometry-analysis focusing on mononuclear phagocyte (MNP) lineages in SARS-CoV-2-infected patients with moderate and severe COVID-19. We provide a deep and comprehensive map of the MNP landscape in COVID-19. A redistribution of monocyte subsets toward intermediate monocytes and a general decrease in circulating DCs was observed in response to infection. Severe disease coincided with the appearance of monocytic myeloid-derived suppressor cell-like cells and a higher frequency of pre-DC2. Furthermore, phenotypic alterations in MNPs, and their late precursors, were cell-lineage-specific and associated either with the general response against SARS-CoV-2 or COVID-19 severity. This included an interferon-imprint in DC1s observed in all patients and a decreased expression of the coinhibitory molecule CD200R in pre-DCs, DC2s, and DC3 subsets of severely sick patients. Finally, unsupervised analysis revealed that the MNP profile, alone, pointed to a cluster of COVID-19 nonsurvivors. This study provides a reference for the MNP response to SARS-CoV-2 infection and unravels mononuclear phagocyte dysregulations associated with severe COVID-19.

Time-Varying Channel Estimation Based on Distributed Compressed Sensing for OFDM Systems.

For orthogonal frequency division multiplexing (OFDM) systems in high-mobility scenarios, the estimation of time-varying multipath channels not only has a large error, which affects system performance, but also requires plenty of pilots, resulting in low spectral efficiency. To address these issues, we propose a time-varying multipath channel estimation method based on distributed compressed sensing and a multi-symbol complex exponential basis expansion model (MS-CE-BEM) by exploiting the temporal correlation and the joint delay sparsity of wideband wireless channels within the duration of multiple OFDM symbols. Furthermore, in the proposed method, a sparse pilot pattern with the self-cancellation of pilot intercarrier interference (ICI) is adopted to reduce the input parameter error of the MS-CE-BEM, and a symmetrical extension technique is introduced to reduce the modeling error. Simulation results show that, compared with existing methods, this proposed method has superior performances in channel estimation and spectrum utilization for sparse time-varying channels.

Nanodrug Augmenting Antitumor Immunity for Enhanced TNBC Therapy via Pyroptosis and cGAS-STING Activation.

Pyroptosis is a proinflammatory form of programmed cell death that results in the release of cellular contents and activation of immune responses. However, GSDME (a pyroptosis-executed protein) is suppressed in many cancers. Herein, we constructed a nanoliposome (GM@LR) for codelivering the GSDME-expressing plasmid and manganese carbonyl (MnCO) into TNBC cells. MnCO generated Mn2+ and carbon monoxide (CO) in the presence of H2O2. The CO-activated caspase-3, which cleaved the expressed GSDME, converting apoptosis to pyroptosis in 4T1 cells. In addition, Mn2+ promoted maturation of dendritic cells (DCs) by the activation of STING signaling pathway. The increased proportion of intratumoral mature DCs brought about massive infiltration of cytotoxic lymphocytes, leading to a robust immune response. Besides, Mn2+ could be applied for magnetic resonance imaging (MRI)-guided metastasis detection. Taken together, our study showed that GM@LR nanodrug could effectively inhibit tumor growth via pyroptosis and STING activation combined immunotherapy.

The effect of valgus reduction on resistant subtrochanteric femoral non-unions: a single-centre report of twenty six cases.

PURPOSE: Re-revision of subtrochanteric non-unions is technically challenging and lacks robust evidence. The results of managing subtrochanteric fractures after multiple failed procedures have rarely been reported in the literature. This study aims to evaluate the effect of valgus reduction on non-united subtrochanteric fractures with single or multiple failed revision surgeries. METHODS: Twenty-six patients with aseptic subtrochanteric fracture non-union underwent failed single or multiple revision procedures after index fracture fixation surgery between 2011 and 2019. The exclusion criteria were as follows: septic non-union, peri-prosthetic, and pathological fractures. Lateral-based wedge valgus reduction and compression at the non-union site using a valgus-contoured DCS together with decortication, debridement, and bone grafting were used. The main outcome measurement was radiological union, pain, LLD, HHS, and restoration of pre-fracture activities. RESULTS: The mean follow-up was 4.5 years (range 3 to 7); prior revision surgeries range from two to five and union at 6.5 months (range 3 to 10) and the delayed union in one case and an infected non-union in one case. The mean LLD was 4 cm (range 3 to 5), which improved to 1.5 cm (range 1 to 4) (P-value < 0.001). The mean VAS was 7 (range 6 to 8), and 24 patients achieved painless ambulation without a walking aid after the union. The mean HHS was 40 (range 25 to 65), which improved to 85 (range 55 to 95) (P-value < 001), achieving 15 excellent, ten good, and one poor results. CONCLUSION: Mechanical optimisation by lateral closing wedge and stable fixation with pre-contoured DCS with biological enhancement resulted in a successful outcome in recalcitrant subtrochanteric non-unions.

Cortical maps of somatosensory perception in human.

Tactile and movement-related somatosensory perceptions are crucial for our daily lives and survival. Although the primary somatosensory cortex is thought to be the key structure of somatosensory perception, various cortical downstream areas are also involved in somatosensory perceptual processing. However, little is known about whether cortical networks of these downstream areas can be dissociated depending on each perception, especially in human. We address this issue by combining data from direct cortical stimulation (DCS) for eliciting somatosensation and data from high-gamma band (HG) elicited during tactile stimulation and movement tasks. We found that artificial somatosensory perception is elicited not only from conventional somatosensory-related areas such as the primary and secondary somatosensory cortices but also from a widespread network including superior/inferior parietal lobules and premotor cortex. Interestingly, DCS on the dorsal part of the fronto-parietal area including superior parietal lobule and dorsal premotor cortex often induces movement-related somatosensations, whereas that on the ventral one including inferior parietal lobule and ventral premotor cortex generally elicits tactile sensations. Furthermore, the HG mapping results of the movement and passive tactile stimulation tasks revealed considerable similarity in the spatial distribution between the HG and DCS functional maps. Our findings showed that macroscopic neural processing for tactile and movement-related perceptions could be segregated.

CD83+ B cells alleviate uveitis through inhibiting DCs by sCD83.

Soluble CD83 (sCD83) exerts immunosuppressive functions in many autoimmune diseases, including experimental autoimmune uveitis (EAU), but the cells and mechanisms involved are unclear. This study showed that CD83+ B cells were the main sources of sCD83. They alleviated the symptoms of EAU and decreased the percentage of T cells and DCs in the eyes and lymph nodes. These CD83+ B cells decreased IL-1ß, IL-18 and IFN-γ secretion by DCs through sCD83. sCD83 interacted with GTPase Ras-related protein (Rab1a) in DCs to promote Rab1a accumulation in autolysosomes and inhibit mTORC1 phosphorylation and NLRP3 expression. Hence, CD83+ B cells play a regulatory role in EAU by secreting sCD83. The lack of regulation of CD83+ B cells might be an important factor leading to hyperimmune activation in patients with autoimmune uveitis. CD83+ B cells suppress activated DCs in uveitis, indicating the potential therapeutic role of CD83+ B cells in uveitis.

Attenuation of renal injury by depleting cDC1 and by repurposing Flt3 inhibitor in anti-GBM disease.

Previous studies found cDC1s to be protective in early stage anti-GBM disease through Tregs, but pathogenic in late stage Adriamycin nephropathy through CD8+ T cells. Flt3 ligand is a growth factor essential for cDC1 development and Flt3 inhibitors are currently used for cancer treatment. We conducted this study to clarify the role and mechanisms of effects of cDC1s at different time points in anti-GBM disease. In addition, we aimed to utilize drug repurposing of Flt3 inhibitors to target cDC1s as a treatment of anti-GBM disease. We found that in human anti-GBM disease, the number of cDC1s increased significantly, proportionally more than cDC2s. The number of CD8+ T cells also increased significantly and their number correlated with cDC1 number. In XCR1-DTR mice, late (day 12-21) but not early (day 3-12) depletion of cDC1s attenuated kidney injury in mice with anti-GBM disease. cDC1s separated from kidneys of anti-GBM disease mice were found to have a pro-inflammatory phenotype (i.e. express high level of IL-6, IL-12 and IL-23) in late but not early stage. In the late depletion model, the number of CD8+ T cells was also reduced, but not Tregs. CD8+ T cells separated from kidneys of anti-GBM disease mice expressed high levels of cytotoxic molecules (granzyme B and perforin) and inflammatory cytokines (TNF-α and IFN-γ), and their expression reduced significantly after cDC1 depletion with diphtheria toxin. These findings were reproduced using a Flt3 inhibitor in wild type mice. Therefore, cDC1s are pathogenic in anti-GBM disease through activation of CD8+ T cells. Flt3 inhibition successfully attenuated kidney injury through depletion of cDC1s. Repurposing Flt3 inhibitors has potential as a novel therapeutic strategy for anti-GBM disease.

TIPE2 deficiency prolongs mouse heart allograft survival by facilitating immature DCs-induced Treg generation.

It has been reported that deletion of tumor necrosis factor-α-induced protein-8 like 2 (TNFAIP8L2, TIPE2) facilitates the activation of T-cell receptors. However, the role of TIPE2 in T-cell-mediated acute transplant rejection remains unclear. To illustrate the underlying cellular mechanisms, we transplanted BALB/c hearts into C57BL/6 wild-type (WT) or C57BL/6 mice deficient for TIPE2 (TIPE2-/-) and found that TIPE2-/- recipient mice showed significantly prolonged survival of heart allografts and suppressed maturation of CD11c+ dendritic cells (DCs), which largely abolished the activation and proliferation of alloreactive T cells and their cytotoxic activity. TIPE2-/- DCs increased CD4+CD25+Foxp3+CD127- regulatory T cells (Tregs)generation, likely by inhibiting DCs maturation and CD80 and CD86 expression. Administration of anti-CD25 abolished the allograft survival induced by TIPE2 deficiency. Moreover, TIPE2 deficiency increased IL-10 production in T cells and in recipient serum and allografts. Mechanistic studies revealed that TIPE2-/- restrained the maturation of DCs via inhibition of PI3K/AKT phosphorylation during alloantigen stimulation. Taken together, TIPE2 deficiency in recipient mice inhibited acute rejection by increasing Tregs generated by immature DCs. Thus, TIPE2 could be a therapeutic target for suppressing rejection in organ transplantation.

Anti-TNFR2 enhanced the antitumor activity of a new HMGN1/3M-052 stimulated dendritic cell vaccine in a mouse model of colon cancer.

Immunotherapy is the new approach for cancer treatment that can be achieved through several strategies, one of which is dendritic cells (DCs) vaccine therapy. However, traditional DC vaccination lacks accurate targeting, so DC vaccine preparation needs to be optimized. Immunosuppressive CD4+Foxp3+ regulatory T cells (Tregs) in the tumor microenvironment can promote tumor immune escape. Therefore, targeting Tregs has become a strategy for tumor immunotherapy. In this study, we found that HMGN1 (N1, a dendritic cell-activating TLR4 agonist) and 3M-052 (a newly synthesized TLR7/8 agonist) synergistically stimulate DCs maturation and increase the production of proinflammatory cytokines TNFα and IL-12. In a colon cancer mice model, vaccination with N1 and 3M-052 stimulated and tumor antigen-loaded DCs combined with anti-TNFR2 inhibited tumor growth in mice, and the antitumor effect was mainly achieved through stimulation of cytotoxic CD8 T cell activation and depletion of Tregs. Overall, the combinating of DC activation by N1 and 3M-052 with inhibition of Tregs by antagonizing TNFR2 as a therapeutic strategy may represent a more effective strategy for cancer treatment.