-
Frontiers in Immunology 2024is a common Gram-negative bacterium. Blood infection caused by is one of the most common causes of human sepsis, which seriously threatens the life of patients. The...
BACKGROUND
is a common Gram-negative bacterium. Blood infection caused by is one of the most common causes of human sepsis, which seriously threatens the life of patients. The immune status of peripheral blood mononuclear cells (PBMCs) based on single-cell RNA sequencing (scRNA-seq) in acute stage and recovery stage of sepsis caused by bloodstream infection has not been studied.
METHODS
A total of 13 subjects were included in this study, 3 healthy controls, 7 patients with bloodstream infection in the acute stage (4 patients died), and 3 patients in the recovery stage. Peripheral blood of all patients was collected and PBMCs were isolated for scRNA-seq analysis. We studied the changes of PBMCs components, signaling pathways, differential genes, and cytokines in acute and recovery stages.
RESULTS
During acute infection we observed a decrease in the proportion of T cells, most probably due to apoptosis and the function of T cell subtypes was disorder. The proportion of monocytes increased in acute stage. Although genes related to their phagocytosis function were upregulated, their antigen presentation capacity-associated genes were downregulated. The expression of IL-1β, IL-18, IFNGR1 and IFNGR2 genes was also increased in monocytes. The proportion of DCs was depleted during the acute stage and did not recover during sepsis recovery. DCs antigen presentation was weakened during the acute stage but recovered fast during the recovery stage. pDCs response to MCP-1 chemokine was weakened, they recovered it quickly during the recovery stage. B cells showed apoptosis both in the acute stage and recovery stage. Their response to complement was weakened, but their antigen presentation function was enhanced. The proportion of NK cells stable during all disease's stages, and the expression of IFN-γ gene was upregulated.
CONCLUSION
The proportion of PBMCs and their immune functions undergo variations throughout the course of the disease, spanning from the acute stage to recovery. These findings provide new insights into the mechanism of PBMCs immune function during bloodstream infection sepsis and recovery and sets the basis for further understanding and treatment.
Topics: Humans; Klebsiella pneumoniae; Klebsiella Infections; Leukocytes, Mononuclear; Male; Female; Middle Aged; Sepsis; Aged; Single-Cell Analysis; Cytokines; Bacteremia; Sequence Analysis, RNA; Adult
PubMed: 38898888
DOI: 10.3389/fimmu.2024.1380211 -
Cell Communication and Signaling : CCS Jun 2024Excessive scar formation such as hypertrophic scars and keloids, resulting from trauma or surgical procedures, present a widespread concern for causing disfigurement,...
Excessive scar formation such as hypertrophic scars and keloids, resulting from trauma or surgical procedures, present a widespread concern for causing disfigurement, discomfort, and functional limitations. Macrophages play pivotal roles in maintaining tissue homeostasis, orchestrating tissue development, repair, and immune responses, and its transition of function and phenotype plays a critical role in regulating the balance between inflammation and tissue regeneration, which is central to cutaneous scar formation. Recent evidence suggests the involvement of Sonic Hedgehog (SHH) in the induction of anti-inflammatory M2-like macrophage phenotypes within tumor microenvironments. In our study, we observed increased SHH expression in human hypertrophic scars, prompting an investigation into its influence on macrophage polarization, efferocytosis, and cutaneous scar formation. Our findings reveal that SHH can enhance oxidative phosphorylation (OXPHOS) in macrophages, augment macrophage efferocytosis, and promote M2 polarization, finally contributing to the progression of cutaneous scar formation. Notably, targeting SHH signaling with vismodegib exhibited promising potential in mitigating scar formation by reversing the effects of enhanced OXPHOS and M2 polarization in macrophages. In conclusion, this study underscores the critical roles of macrophage metabolism, particularly OXPHOS, efferocytosis and SHH signaling in cutaneous scar formation. Understanding these mechanisms provides new avenues for potential interventions and scar prevention strategies.
Topics: Hedgehog Proteins; Macrophages; Humans; Oxidative Phosphorylation; Animals; Phagocytosis; Cicatrix, Hypertrophic; Mice; Signal Transduction; Cicatrix; Mice, Inbred C57BL; Anilides; Pyridines; Efferocytosis
PubMed: 38898530
DOI: 10.1186/s12964-024-01692-w -
Journal of Agricultural and Food... Jun 2024Excessive hydrogen peroxide (HO) generated during retinal cell metabolic activity could lead to oxidative degeneration of retinal pigment epithelium (RPE) tissue, a...
Excessive hydrogen peroxide (HO) generated during retinal cell metabolic activity could lead to oxidative degeneration of retinal pigment epithelium (RPE) tissue, a specific pathological process implicated in various retinal diseases resulting in blindness, which can be mitigated by taking dietary antioxidants to prevent inflammation and impaired cellular dysfunction. This study tested the hypothesis that damages induced by oxidative stresses can be mitigated by lutein in a HO-challenged model, which was based on an ARPE-19 cell monolayer cultured on three-dimensional (3D)-printed fibrous scaffolds. Pretreating these models with lutein (0.5 μM) for 24 h can significantly lower the oxidative stress and maintain phagocytosis and barrier function. Moreover, lutein can modulate the NLRP3 inflammasome, leading to a ∼40% decrease in the pro-inflammatory cytokine (IL-1β and IL-18) levels. Collectively, this study suggests that the 3D RPE model is an effective tool to examine the capability of lutein to modulate cellular functionalities and regulate NLRP3 inflammation.
PubMed: 38897610
DOI: 10.1021/acs.jafc.4c01537 -
Vascular Pharmacology Jun 2024Neutrophils perform various functions in a circadian-dependent manner; therefore, we investigated here whether the effect of alpha1-antitrypsin (AAT), used as...
AIMS
Neutrophils perform various functions in a circadian-dependent manner; therefore, we investigated here whether the effect of alpha1-antitrypsin (AAT), used as augmentation therapy, is dependent on the neutrophil circadian clock. AAT is a vital regulator of neutrophil functions, and its qualitative and/or quantitative defects have significant implications for the development of respiratory diseases.
METHODS
Whole blood from 12 healthy women [age years, mean (SD) 29.92 (5.48) was collected twice daily, 8 h apart, and incubated for 30 min at 37 °C alone or with additions of 2 mg/ml AAT (Respreeza) and/or 5 μg/ml lipopolysaccharide (LPS) from Escherichia coli. Neutrophils were then isolated to examine gene expression, migration and phagocytosis.
RESULTS
The expression of CD14, CD16, CXCR2 and SELL (encoding CD62L) genes was significantly higher while CDKN1A lower in the afternoon than in the morning neutrophils from untreated blood. Neutrophils isolated in the afternoon had higher migratory and phagocytic activity. Morning neutrophils isolated from AAT-pretreated blood showed higher expression of CXCR2 and SELL than those from untreated morning blood. Pretreatment of blood with AAT enhanced migratory properties of morning but not afternoon neutrophils. Of all genes analysed, only CXCL8 expression was strongly upregulated in morning and afternoon neutrophils isolated from LPS-pretreated blood, whereas CXCR2 expression was downregulated in afternoon neutrophils. The addition of AAT did not reverse the effects of LPS.
SIGNIFICANCE
The circadian clock of myeloid cells may affect the effectiveness of various therapies, including AAT therapy used to treat patients with AAT deficiency, and needs further investigation.
PubMed: 38897556
DOI: 10.1016/j.vph.2024.107396 -
The American Journal of Pathology Jun 2024Accumulating evidence has substantiated the potential of ambient particulate matter (PM) to elicit detrimental health consequences in the respiratory system, notably...
Accumulating evidence has substantiated the potential of ambient particulate matter (PM) to elicit detrimental health consequences in the respiratory system, notably airway inflammation. Macrophages, a pivotal component of the innate immune system, assume a crucial function in responding to exogenous agents. However, the roles and detailed mechanisms in regulating PM-induced airway inflammation remain unclear. Our study revealed that PM had the ability to stimulate the formation of macrophage extracellular traps (METs) both in vitro and in vivo. This effect was found to be dependent on peptidylarginine deiminase type 4 (PAD4)-mediated histone citrullination. Additionally, reactive oxygen species were also found to be involved in the formation of PM-induced METs, in parallel with PAD4. Genetic deletion of PAD4 in macrophages resulted in an up-regulation of inflammatory cytokine expression. Moreover, mice with PAD4-specific knockout in myeloid cells exhibited exacerbated PM-induced airway inflammation. Mechanistically, inhibition of METs suppressed the phagocytic ability in macrophages, leading to airway epithelial injuries and an aggravated PM-induced airway inflammation. The present study demonstrates that METs play a crucial role in promoting the phagocytosis and clearance of PM by macrophages, thereby suppressing airway inflammation. Furthermore, it suggests that activation of METs may represent a novel therapeutic strategy for PM-related airway disorders.
PubMed: 38897538
DOI: 10.1016/j.ajpath.2024.05.008 -
IEEE Transactions on Neural Networks... Jun 2024Reconstructing gene regulatory networks (GRNs) using single-cell RNA sequencing (scRNA-seq) data holds great promise for unraveling cellular fate development and...
Reconstructing gene regulatory networks (GRNs) using single-cell RNA sequencing (scRNA-seq) data holds great promise for unraveling cellular fate development and heterogeneity. While numerous machine-learning methods have been proposed to infer GRNs from scRNA-seq gene expression data, many of them operate solely in a statistical or black box manner, limiting their capacity for making causal inferences between genes. In this study, we introduce GRN inference with Accuracy and Causal Explanation (GRACE), a novel graph-based causal autoencoder framework that combines a structural causal model (SCM) with graph neural networks (GNNs) to enable GRN inference and gene causal reasoning from scRNA-seq data. By explicitly modeling causal relationships between genes, GRACE facilitates the learning of regulatory context and gene embeddings. With the learned gene signals, our model successfully decoding the causal structures and alleviates the accurate determination of multiple attributes of gene regulation that is important to determine the regulatory levels. Through extensive evaluations on seven benchmarks, we demonstrate that GRACE outperforms 14 state-of-the-art GRN inference methods, with the incorporation of causal mechanisms significantly enhancing the accuracy of GRN and gene causality inference. Furthermore, the application to human peripheral blood mononuclear cell (PBMC) samples reveals cell type-specific regulators in monocyte phagocytosis and immune regulation, validated through network analysis and functional enrichment analysis.
PubMed: 38896510
DOI: 10.1109/TNNLS.2024.3412753 -
BioRxiv : the Preprint Server For... Jun 2024CLN3 Batten disease (also known as Juvenile Neuronal Ceroid Lipofuscinosis; JNCL) is a lysosomal storage disorder that typically initiates with retinal degeneration but...
PURPOSE
CLN3 Batten disease (also known as Juvenile Neuronal Ceroid Lipofuscinosis; JNCL) is a lysosomal storage disorder that typically initiates with retinal degeneration but is followed by seizure onset, motor decline and premature death. Patient-derived CLN3 disease iPSC-RPE cells show defective phagocytosis of photoreceptor outer segments (POSs). Because modifier genes are implicated in CLN3 disease, our goal here was to investigate a direct link between mutation and POS phagocytosis defect.
METHODS
Isogenic control and mutant stem cell lines were generated by CRISPR-Cas9-mediated biallelic deletion of exons 7 and 8. A transgenic ( ) Yucatan miniswine was also used to study the impact of mutation on POS phagocytosis. POS phagocytosis by cultured RPE cells was analyzed by Western blotting and immunohistochemistry. Electroretinogram, optical coherence tomography and histological analysis of and wild-type miniswine eyes were carried out at 6-, 36-, or 48-month age.
RESULTS
RPE ( RPE) displayed reduced POS binding and consequently decreased uptake of POS compared to isogenic control RPE cells. Furthermore, wild-type miniswine RPE cells phagocytosed POS less efficiently than wild-type POS. Consistent with decreased POS phagocytosis, lipofuscin/autofluorescence was decreased in miniswine RPE at 36 months-of-age and was followed by almost complete loss of photoreceptors at 48 months of age.
CONCLUSIONS
mutation (that affects up to 85% patients) affects both RPE and POSs and leads to photoreceptor cell loss in CLN3 disease. Furthermore, both primary RPE dysfunction and mutant POS independently contribute to impaired POS phagocytosis in CLN3 disease.
PubMed: 38895469
DOI: 10.1101/2024.06.09.597388 -
BioRxiv : the Preprint Server For... Jun 2024Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of hematological malignancies but has been clinically less effective in solid tumors....
UNLABELLED
Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of hematological malignancies but has been clinically less effective in solid tumors. Engineering macrophages with CARs has emerged as a promising approach to overcome some of the challenges faced by CAR-T cells due to the macrophage's ability to easily infiltrate tumors, phagocytose their targets, and reprogram the immune response. We engineered CAR-macrophages (CAR-Ms) to target chondroitin sulfate proteoglycan 4 (CSPG4), an antigen expressed in melanoma, and several other solid tumors. CSPG4-targeting CAR-Ms exhibited specific phagocytosis of CSPG4-expressing melanoma cells. Combining CSPG4-targeting CAR-Ms with CD47 blocking antibodies synergistically enhanced CAR-M-mediated phagocytosis and effectively inhibited melanoma spheroid growth in 3D. Furthermore, CSPG4-targeting CAR-Ms inhibited melanoma tumor growth in mouse models. These results suggest that CSPG4-targeting CAR-M immunotherapy is a promising solid tumor immunotherapy approach for treating melanoma.
STATEMENT OF SIGNIFICANCE
We engineered macrophages with CARs as an alternative approach for solid tumor treatment. CAR-macrophages (CAR-Ms) targeting CSPG4, an antigen expressed in melanoma and other solid tumors, phagocytosed melanoma cells and inhibited melanoma growth . Thus, CSPG4-targeting CAR-Ms may be a promising strategy to treat patients with CSPG4-expressing tumors.
PubMed: 38895447
DOI: 10.1101/2024.06.04.597413 -
Cancers May 2024Recent studies highlight the integral role of the interferon gamma receptor (IFNγR) pathway in T cell-mediated cytotoxicity against solid but not liquid tumors. IFNγ...
Recent studies highlight the integral role of the interferon gamma receptor (IFNγR) pathway in T cell-mediated cytotoxicity against solid but not liquid tumors. IFNγ not only directly facilitates tumor cell death by T cells but also indirectly promotes cytotoxicity via myeloid phagocytosis in the tumor microenvironment. Meanwhile, full human ex vivo immune checkpoint drug screening remains challenging. We hypothesized that an engineered gamma interferon activation site response element luciferase reporter (GAS-Luc2) can be utilized for immune checkpoint drug screening in diverse ex vivo T cell-solid tumor cell co-culture systems. We comprehensively profiled cell surface proteins in ATCC's extensive collection of human tumor and immune cell lines, identifying those with endogenously high expression of established and novel immune checkpoint molecules and binding ligands. We then engineered three GAS-Luc2 reporter tumor cell lines expressing immune checkpoints PD-L1, CD155, or B7-H3/CD276. Luciferase expression was suppressed upon relevant immune checkpoint-ligand engagement. In the presence of an immune checkpoint inhibitor, T cells released IFNγ, activating the JAK-STAT pathway in GAS-Luc2 cells, and generating a quantifiable bioluminescent signal for inhibitor evaluation. These reporter lines also detected paracrine IFNγ signaling for immune checkpoint-targeted ADCC drug screening. Further development into an artificial antigen-presenting cell line (aAPC) significantly enhanced T cell signaling for superior performance in these ex vivo immune checkpoint drug screening platforms.
PubMed: 38893085
DOI: 10.3390/cancers16111965 -
Nutrients May 2024Longan ( Lour.) is a kind of traditional fruit used as a medicine and a food. Fresh longan is primarily consumed as a fruit, whereas dried longan is commonly employed... (Comparative Study)
Comparative Study
Longan ( Lour.) is a kind of traditional fruit used as a medicine and a food. Fresh longan is primarily consumed as a fruit, whereas dried longan is commonly employed for medicinal purposes. The differences in the immunomodulatory activities and mechanisms of polysaccharides between dried and fresh longan remain unclear. The present study comparatively analyzed the mechanisms of macrophage activation induced by polysaccharides from dried (LPG) and fresh longan (LPX). The results revealed that LPG and LPX differentially promoted macrophage phagocytosis and the secretion of NO, TNF-α, and IL-6. RNA-seq analysis revealed that LPG and LPX differentially affected gene expression in macrophages. The LPG treatment identified and chemokine-related genes as core genes, while and interferon-related genes were the core genes affected by LPX. A comprehensive analysis of the differentially expressed genes showed that LPG initiated macrophage activation primarily through the TLR2/4-mediated and CLR-mediated NF-κB signaling pathways. LPX initiated macrophage activation predominantly via the CLR-mediated and NLR-mediated MAPK and NF-κB signaling pathways. Interestingly, the non-classical NF-κB signaling pathway was activated by polysaccharides in both dried and fresh longan to elicit a slow, mild immune response. LPG tends to promote immune cell migration to engage in the immune response, while LPX facilitates antigen presentation to promote T cell activation. These findings contribute insights into the mechanisms underlying the differences in bioactivity between dried and fresh longan and their potential applications in immune-enhancing strategies and functional-food development.
Topics: Macrophage Activation; Polysaccharides; Animals; Mice; RAW 264.7 Cells; Macrophages; Signal Transduction; Fruit; Sapindaceae; Phagocytosis; NF-kappa B
PubMed: 38892587
DOI: 10.3390/nu16111654