Understanding the Role of LFA-1 in Leukocyte Adhesion Deficiency Type I (LAD I): Moving towards Inflammation?

Cyclic GMP-AMP Synthase (cGAS) Deletion Promotes Less Prominent Inflammatory Macrophages and Sepsis Severity in Catheter-Induced Infection and LPS Injection Models

Activation of cGAS, a cytosolic receptor recognizing double-stranded DNA, in macrophages is important in sepsis (a life-threatening condition caused by infection). The responses against sepsis induced by subcutaneous implantation of the Pseudomonas-contaminated catheters in cGAS-deficient (cGAS-/-) mice were lower than in wild-type (WT) mice as indicated by liver enzymes, white blood cell count, cytokines, and M1-polarized macrophages in the spleens. Likewise, a lethal dose of lipopolysaccharide (LPS) induced less severe sepsis severity as determined by mortality, organ injury, cell-free DNA, and serum cytokines. Patterns of the transcriptome of lipopolysaccharide (LPS)-stimulated bone marrow-derived macrophages were clearly different between cGAS-/- and WT cells. Gene set enrichment analysis (GSEA; a computational statistical determination of the gene set) indicated more prominent enrichment of oxidative phosphorylation (OXPHOS; the mitochondrial function) and mTORC1 pathways in LPS-activated cGAS-/- macrophages compared with WT. Meanwhile, LPS upregulated cGAS and increased cGAMP (a cGAS inducer) only in WT macrophages along with less severe inflammation in cGAS-/- macrophages, as indicated by supernatant cytokines, pro-inflammatory molecules (nuclear factor kappa B; NF-κB), M1 polarization (IL-1β, CD80, and CD86), and macrophage extracellular traps (METs; web-like structures composed of DNA, histones, and other proteins) through the detection of citrullinated histone 3 (CitH3) in supernatant and immunofluorescent visualization. In conclusion, less prominent pro-inflammatory responses of cGAS-/- macrophages than WT were demonstrated in mice (catheter-induced sepsis and LPS injection model) and in vitro (transcriptomic analysis, macrophage polarization, and METs).

T Cell-Targeting Nanotherapies for Atherosclerosis

Cardiovascular diseases remain the leading cause of mortality worldwide. Specifically, atherosclerosis is a primary cause of acute cardiac events. However, current therapies mainly focus on lipid-lowering versus addressing the underlying inflammatory response that leads to its development and progression. Nanoparticle-mediated drug delivery offers a promising approach for targeting and regulating these inflammatory responses. In atherosclerotic lesions, inflammatory cascades result in increased T helper (Th) 1 and Th17 activity and reduced T regulatory activation. The regulation of T cell responses is critical in preventing the inflammatory imbalance in atherosclerosis, making them a key therapeutic target for nanotherapy to achieve precise atherosclerosis treatment. By functionalizing nanoparticles with targeting modalities, therapeutic agents can be delivered specifically to immune cells in atherosclerotic lesions. In this Review, we outline the role of T cells in atherosclerosis, examine current nanotherapeutic strategies for targeting T cells and modulating their differentiation, and provide perspectives for the development of nanoparticles specifically tailored to target T cells for the treatment of atherosclerosis.

Utilizing AI for the Identification and Validation of Novel Therapeutic Targets and Repurposed Drugs for Endometriosis

Endometriosis affects over 190 million women globally, and effective therapies are urgently needed to address the burden of endometriosis on women's health. Using an artificial intelligence (AI)-driven target discovery platform, two unreported therapeutic targets, guanylate-binding protein 2 (GBP2) and hematopoietic cell kinase (HCK) are identified, along with a drug repurposing target, integrin beta 2 (ITGB2) for the treatment of endometriosis. GBP2, HCK, and ITGB2 are upregulated in human endometriotic specimens. siRNA-mediated knockdown of GBP2 and HCK significantly reduced cell viability and proliferation while stimulating apoptosis in endometrial stromal cells. In subcutaneous and intraperitoneal endometriosis mouse models, siRNAs targeting GBP2 and HCK notably reduced lesion volume and weight, with decreased proliferation and increased apoptosis within lesions. Both subcutaneous and intraperitoneal administration of Lifitegrast, an approved ITGB2 antagonist, effectively suppresses lesion growth. Collectively, these data present Lifitegrast as a previously unappreciated intervention for endometriosis treatment and identify GBP2 and HCK as novel druggable targets in endometriosis treatment. This study underscores AI's potential to accelerate the discovery of novel drug targets and facilitate the repurposing of treatment modalities for endometriosis.

Neutrophil diversity and function in health and disease

Neutrophils, the most abundant type of granulocyte, are widely recognized as one of the pivotal contributors to the acute inflammatory response. Initially, neutrophils were considered the mobile infantry of the innate immune system, tasked with the immediate response to invading pathogens. However, recent studies have demonstrated that neutrophils are versatile cells, capable of regulating various biological processes and impacting both human health and disease. Cytokines and other active mediators regulate the functional activity of neutrophils by activating multiple receptors on these cells, thereby initiating downstream signal transduction pathways. Dysfunctions in neutrophils and disruptions in neutrophil homeostasis have been implicated in the pathogenesis of numerous diseases, including cancer and inflammatory disorders, often due to aberrant intracellular signaling. This review provides a comprehensive synthesis of neutrophil biological functions, integrating recent advancements in this field. Moreover, it examines the biological roles of receptors on neutrophils and downstream signaling pathways involved in the regulation of neutrophil activity. The pathophysiology of neutrophils in numerous human diseases and emerging therapeutic approaches targeting them are also elaborated. This review also addresses the current limitations within the field of neutrophil research, highlighting critical gaps in knowledge that warrant further investigation. In summary, this review seeks to establish a comprehensive and multidimensional model of neutrophil regulation, providing new perspectives for potential clinical applications and further research.

Comparative transcriptomic analysis revealed potential mechanisms regulating the hypertrophy of goose pectoral muscles

Pectoral muscle development is an important economic trait. According to the different essence, muscle development can be divided into 2 processes: embryonic muscle fiber generation and postnatal muscle fiber hypertrophy, and postnatal muscle fiber hypertrophy has a greater impact on muscle development than the number of muscle fibers formed during the embryonic phase in poultry. However, the underlying mechanisms regulating the hypertrophy of goose pectoral muscles have not been elucidated. Therefore, the purpose of the present study was to conduct transcriptome sequencing in pectoral muscles of both Landes (LD) and Sichuan White (SW) geese at 6, 10, and 30 weeks of age to reveal the molecular mechanisms regulating pectoral muscle hypertrophy through intra-breed and inter-breed bioinformatics analyses. Phenotypically, the pectoral muscle weight/index of LD and SW geese increased from 6 to 30 weeks of age, and except for the pectoral muscle index at 10 weeks of age (P = 0.962), at the same age, the pectoral muscle weight/index of LD geese were significantly higher than that of SW geese (P < 0.05). In transcriptional regulation, intra-breed bioinformatics analysis identified 3331 genes whose expression levels were opposite to the trend of pectoral muscle hypertrophy both in LD and SW geese, and the 3331 genes were mainly enriched into abundant KEGG pathways related to lipid metabolism, proliferation/apoptosis, and immune response. Moreover, 23 genes (including SLC2A10, TNFRSF1A, PRKAA1, SLC27A4, ITGB2, THY1, RHOA, MYL10, ACTB, PRKCB, PIK3R2, RAC2, DMD, LATS2, YAP1, WWTR1, SMAD7, CTGF, FGF1, AXIN2, GLI2, ID2, and CCND2) who were enriched in 6 crosstalk pathways named viral myocarditis, insulin resistance, sphingolipid signaling pathway, hippo signaling pathway, chemokine signaling pathway, and leukocyte transendothelial migration were identified as the key candidate genes regulating the hypertrophy of goose pectoral muscles. In inter-breed bioinformatics analysis, abundant different expression genes (DEGs) related to lipid metabolism, immune response, and proliferation/apoptosis were identified between LD and SW geese too, and compared with SW geese, the expression level of MYL10 in LD geese was lower, while the expression levels of GLI2/CTGF/SMAD7 in LD geese were higher. These results suggested that the hypertrophy of goose pectoral muscles might be achieved through more lipid deposition and less leukocyte infiltration to promote the proliferation of cells within the muscles, and the low expression of MYL10 and high expressions of GLI2/CTGF/SMAD7 might the keys to induce the pectoral muscle hypertrophy of LD geese from 6 to 30 weeks of age over that of SW geese. All data the present study obtained will provide new insights into the molecular mechanisms regulating the hypertrophy of goose pectoral muscles.

Impact of psychological stressors on natural killer cell function: A comprehensive analysis based on stressor type, duration, intensity, and species

Patients with natural killer (NK) cell deficiency or dysfunction are more susceptible to infections by Herpesviridae viruses, herpesvirus-related cancers, and macrophage activation syndromes. This review summarizes research on NK cell dysfunction following psychological stress, focusing on stressor type, duration, age of exposure, and species studied. Psychological stressors negatively affect NK cell activity (NKCA) across species. Prolonged stress leads to more significant decreases in NK cell number and function, with rehabilitation efforts proving ineffective in reversing these effects. Early life and prolonged stress exposure particularly increases the risk of infections and cancer due to impaired NKCA. The review also highlights that stress impacts males and females differently, with females exhibiting a more immunosuppressed NK cell phenotype. Notably, mice respond differently compared to humans and other animals, making them unsuitable for NK cell stress-related studies. Most studies measured NKCA using cytolytic assays against K-562 or YAC-1 cells. Although the exact mechanisms of NK cell dysfunction under stress remain unclear, potential causes include reduced release of secretory lysosomes with perforin or granzyme, impaired NK cell synapse formation, decreased expression of synapse-related molecules like CD2 or LFA-1 (CD11a), altered activating receptor expression, and dysregulated signaling pathways, such as decreased Erk1/2 phosphorylation and NFkB signaling. These mechanisms are not mutually exclusive, and future research is needed to clarify these pathways and develop therapeutic interventions for stress-induced immune dysregulation.

Exploring the inflammation-related mechanisms of Lingguizhugan decoction on right ventricular remodeling secondary to pulmonary arterial hypertension based on integrated strategy using UPLC-HRMS, systems biology approach, and experimental validation

BACKGROUND

Pulmonary arterial hypertension (PAH) and the consequent right heart dysfunction persist with high morbidity and mortality, and the mechanisms and pharmacologic interventions for chronic right-sided heart failure (RHF) have not been adequately investigated. Research has shown that prolonged inflammation is critical in precipitating the progression of PAH-associated right heart pathology. Some research demonstrated that Lingguizhugan decoction (LGZGD), as a classical Chinese medicine formula, had beneficial effects in alleviating PAH and RHF, while its underlying mechanisms involved are not fully elucidated.

PURPOSE

Based on that, this study aims to investigate the effects and underlying mechanisms of LGZGD on PAH-induced RHF.

STUDY DESIGN

In this study, we identified the serum constituents and deciphered the potential anti-inflammatory mechanism and crucial components of LGZGD using combined approaches of UPLC-HRMS, transcriptomic analysis, and molecular docking techniques. Finally, we used in vivo experiments to verify the expression of key targets in the monocrotaline (MCT)-induced RHF model and the intervene effect of LGZGD.

RESULTS

Integrated strategies based on UPLC-HRMS and systems biology approach combined with in vivo experimental validation showed that LGZGD could improve right heart fibrosis and dysfunction via regulating diverse inflammatory signaling pathways and the activity of immune cells, including chemokine family CCL2, CXCR4, leukocyte integrins family ITGAL, ITGB2, and M2 macrophage infiltration, as well as lipid peroxidation-associated HMOX1, NOX4, and 4-HNE.

CONCLUSION

The present research demonstrated for the first time that LGZGD might improve PAH-induced RHF through multiple anti-inflammatory signaling and inhibition of ferroptosis, which could provide certain directions for future research in related fields.

Signalling Pathways of Inflammation and Cancer in Human Mononuclear Cells: Effect of Nanoparticle Air Pollutants

Fine inhalable particulate matter (PM) triggers an inflammatory response in the airways and activates mononuclear cells, mediators of tissue homeostasis, and tumour-promoting inflammation. We have assessed ex vivo responses of human monocytes and monocyte-derived macrophages to standardised air pollutants: carbon black, urban dust, and nanoparticulate carbon black, focusing on their pro-inflammatory and DNA-damaging properties. None of the PM (100 μg/mL/24 h) was significantly toxic to the cells, aside from inducing oxidative stress, fractional DNA damage, and inhibiting phagocytosis. TNFα was only slightly increased. PM nanoparticles increase the expression and activate DNA-damage-related histone H2A.X as well as pro-inflammatory NF-κB. We have shown that the urban dust stimulates the pathway of DNA damage/repair via the selective post-translational phosphorylation of H2A.X while nanoparticulate carbon black increases inflammation via activation of NF-κB. Moreover, the inflammatory response to lipopolysaccharide was significantly stronger in macrophages pre-exposed to urban dust or nanoparticulate carbon black. Our data show that airborne nanoparticles induce PM-specific, epigenetic alterations in the subsets of cultured mononuclear cells, which may be quantified using binary fluorescence scatterplots. Such changes intercede with inflammatory signalling and highlight important molecular and cell-specific epigenetic mechanisms of tumour-promoting inflammation.

Sweet syndrome associated with moderate leukocyte adhesion deficiency type I: a case report and review of the literature

Sweet syndrome is an acute febrile neutrophilic dermatosis characterized by the infiltration of neutrophils into the skin. It may occur idiopathically or be linked to malignancies, inflammatory or autoimmune diseases. Leukocyte adhesion deficiency type I (LAD-I) is an inborn error immunity wherein leukocytes lack adhesion molecules necessary for migration to infection sites due to mutations in the CD18 gene encoding β2 integrins. We present a case of a 16-month-old female initially diagnosed and treated for Sweet syndrome based on histopathological findings with recurrent flare episodes. Subsequent workup revealed LAD-I, making this case the first documented association between Sweet syndrome and LAD-I. Moreover, we reviewed the pertinent literatures detailing the concurrence of neutrophilic dermatosis and immunodeficiency disorders. This case underscores the significance of comprehensive evaluation for Sweet syndrome patients who are refractory to conventional treatments.

Functional neutrophil disorders: Chronic granulomatous disease and beyond

Since their description by Metchnikoff in 1905, phagocytes have been increasingly recognized to be the entities that traffic to sites of infection and inflammation, engulf and kill infecting organisms, and clear out apoptotic debris all the while making antigens available and accessible to the lymphoid organs for future use. Therefore, phagocytes provide the gateway and the first check in host protection and immune response. Disorders in killing and chemotaxis lead not only to infection susceptibility, but also to autoimmunity. We aim to describe chronic granulomatous disease and the leukocyte adhesion deficiencies as well as myeloperoxidase deficiency and G6PD deficiency as paradigms of critical pathways.

Integrins in Health and Disease-Suitable Targets for Treatment?

Integrin receptors are heterodimeric surface receptors that play multiple roles regarding cell-cell communication, signaling, and migration. The four members of the β2 integrin subfamily are composed of an alternative α (CD11a-d) subunit, which determines the specific receptor properties, and a constant β (CD18) subunit. This review aims to present insight into the multiple immunological roles of integrin receptors, with a focus on β2 integrins that are specifically expressed by leukocytes. The pathophysiological role of β2 integrins is confirmed by the drastic phenotype of patients suffering from leukocyte adhesion deficiencies, most often resulting in severe recurrent infections and, at the same time, a predisposition for autoimmune diseases. So far, studies on the role of β2 integrins in vivo employed mice with a constitutive knockout of all β2 integrins or either family member, respectively, which complicated the differentiation between the direct and indirect effects of β2 integrin deficiency for distinct cell types. The recent generation and characterization of transgenic mice with a cell-type-specific knockdown of β2 integrins by our group has enabled the dissection of cell-specific roles of β2 integrins. Further, integrin receptors have been recognized as target receptors for the treatment of inflammatory diseases as well as tumor therapy. However, whereas both agonistic and antagonistic agents yielded beneficial effects in animal models, the success of clinical trials was limited in most cases and was associated with unwanted side effects. This unfavorable outcome is most probably related to the systemic effects of the used compounds on all leukocytes, thereby emphasizing the need to develop formulations that target distinct types of leukocytes to modulate β2 integrin activity for therapeutic applications.

A narrative review on the role of magnesium in immune regulation, inflammation, infectious diseases, and cancer

BACKGROUND

Magnesium (Mg) has gained much importance recently because of its unique range of biological functions. It is one of the most significant micronutrients in biological systems. This review aims to outline the immune-regulating actions of Mg and its crucial role in regulating inflammation and immune response to infectious agents and malignancies.

METHODS

We conducted a literature review on MEDLINE, PubMed, EMBASE, Web of Science to determine the impact of Mg on immune regulation in three settings of inflammation, infection, and cancer. We thoroughly examined all abstracts and full-text articles and selected the most relevant ones for inclusion in this review.

RESULTS

Mg has long been associated with immunological responses, both nonspecific and specific. It plays a pivotal role in diverse immune responses by participating in multiple mechanisms. It facilitates substance P binding to lymphoblasts, promotes T helper, B cell, and macrophage responses to lymphokines, and facilitates antibody-dependent cytolysis and immune cell adherence. Besides, Mg serves as a cofactor for C'3 convertase and immunoglobulin synthesis. It additionally boasts a significant anti-cancer effect. Chronic Mg deficiency leads to enhanced baseline inflammation associated with oxidative stress, related to various age-associated morbidities. A deficiency of Mg in rodents has been observed to impact the cell-mediated immunity and synthesis of IgG adversely. This deficiency can lead to various complications, such as lymphoma, histaminosis, hypereosinophilia, increased levels of IgE, and atrophy of the thymus. The immunological consequences of Mg deficiency in humans can be influenced by the genetic regulation of Mg levels in blood cells. Mg can also mediate cell cycle progression. There has been a renewed interest in the physiology and therapeutic efficacy of Mg. However, the in-depth mechanisms, their clinical significance, and their importance in malignancies and inflammatory disorders still need to be clarified.

CONCLUSIONS

Mg is essential for optimal immune function and regulating inflammation. Deficiency in Mg can lead to temporary or long-term immune dysfunction. A balanced diet usually provides sufficient Mg, but supplementation may be necessary in some cases. Excessive supplementation can have negative impacts on immune function and should be avoided. This review provides an update on the importance of Mg in an immune response against cancer cells and infectious agents and how it regulates inflammation, oxidative stress, cell progression, differentiation, and apoptosis.

Defective Treg generation and increased type 3 immune response in leukocyte adhesion deficiency 1

In 15 Turkish LAD-1 patients and controls, we assessed the impact of pathogenic ITGB2 mutations on Th17/Treg differentiation and functions, and innate lymphoid cell (ILC) subsets. The percentage of peripheral blood Treg cells, in vitro-generated induced Tregs differentiated from naive CD4⁺ T cells were decreased despite the elevated absolute counts of CD4⁺ cells in LAD1 patients. Serum IL-23 levels were elevated in LAD1 patients. Post-curdlan stimulation, LAD1 patient-derived PBMCs produced more IL-17A. Additionally, the percentages of CD18-deficient Th17 cells expanded from total or naïve CD4⁺ T cells were higher. The blood ILC3 subset was significantly elevated in LAD1. Finally, LAD1 PBMCs showed defects in trans-well migration and proliferation and were more resistant to apoptosis. Defects in de novo generation of Tregs from CD18-deficient naïve T cells and elevated Th17s, and ILC3s in LAD1 patients' peripheral blood suggest a type 3-skewed immunity and may contribute to LAD1-associated autoimmune symptoms.

Tff3-/- Knock-Out Mice with Altered Lipid Metabolism Exhibit a Lower Level of Inflammation following the Dietary Intake of Sodium Chloride for One Week

A high salt intake causes hemodynamic changes and promotes immune response through cell activation and cytokine production, leading to pro-inflammatory conditions. Transgenic Tff3^-/- knock-out mice (TFF3ko) (n = 20) and wild-type mice (WT) (n = 20) were each divided into the (1) low-salt (LS) group and (2) high-salt (HS) group. Ten-week-old animals were fed with standard rodent chow (0.4% NaCl) (LS) or food containing 4% NaCl (HS) for one week (7 days). Inflammatory parameters from the sera were measured by Luminex assay. The integrin expression and rates of T cell subsets of interest from the peripheral blood leukocytes (PBLs) and mesenteric lymph nodes (MLNs) were measured using flow cytometry. There was a significant increase in high-sensitivity C reactive protein (hsCRP) only in the WT mice following the HS diet, while there were no significant changes in the serum levels of IFN-γ, TNF-α, IL-2, IL-4, or IL-6 as a response to treatment in either study groups. The rates of CD4⁺CD25⁺ T cells from MLNs decreased, while CD3⁺γδTCR⁺ from peripheral blood increased following the HS diet only in TFF3ko. γδTCR expressing T cell rates decreased in WT following the HS diet. The CD49d/VLA-4 expression decreased in the peripheral blood leukocytes in both groups following the HS diet. CD11a/LFA-1 expression significantly increased only in the peripheral blood Ly6C^-CD11a^high monocytes in WT mice following salt loading. In conclusion, salt-loading in knock-out mice caused a lower level of inflammatory response compared with their control WT mice due to gene depletion.

Zebrafish: A Relevant Genetic Model for Human Primary Immunodeficiency (PID) Disorders?

Primary immunodeficiency (PID) disorders, also commonly referred to as inborn errors of immunity, are a heterogenous group of human genetic diseases characterized by defects in immune cell development and/or function. Since these disorders are generally uncommon and occur on a variable background profile of potential genetic and environmental modifiers, animal models are critical to provide mechanistic insights as well as to create platforms to underpin therapeutic development. This review aims to review the relevance of zebrafish as an alternative genetic model for PIDs. It provides an overview of the conservation of the zebrafish immune system and details specific examples of zebrafish models for a multitude of specific human PIDs across a range of distinct categories, including severe combined immunodeficiency (SCID), combined immunodeficiency (CID), multi-system immunodeficiency, autoinflammatory disorders, neutropenia and defects in leucocyte mobility and respiratory burst. It also describes some of the diverse applications of these models, particularly in the fields of microbiology, immunology, regenerative biology and oncology.

Impaired Treg-DC interactions contribute to autoimmunity in leukocyte adhesion deficiency type 1

Leukocyte adhesion deficiency type 1 (LAD-1) is a rare disease resulting from mutations in the gene encoding for the common β-chain of the β2-integrin family (CD18). The most prominent clinical symptoms are profound leukocytosis and high susceptibility to infections. Patients with LAD-1 are prone to develop autoimmune diseases, but the molecular and cellular mechanisms that result in coexisting immunodeficiency and autoimmunity are still unresolved. CD4+FOXP3+ Treg are known for their essential role in preventing autoimmunity. To understand the role of Treg in LAD-1 development and manifestation of autoimmunity, we generated mice specifically lacking CD18 on Treg (CD18Foxp3), resulting in defective LFA-1 expression. Here, we demonstrate a crucial role of LFA-1 on Treg to maintain immune homeostasis by modifying T cell-DC interactions and CD4+ T cell activation. Treg-specific CD18 deletion did not impair Treg migration into extralymphatic organs, but it resulted in shorter interactions of Treg with DC. In vivo, CD18Foxp3 mice developed spontaneous hyperplasia in lymphatic organs and diffuse inflammation of the skin and in multiple internal organs. Thus, LFA-1 on Treg is required for the maintenance of immune homeostasis.