Sevoflurane blocks KLF5-mediated transcriptional activation of ITGB2 to inhibit macrophage infiltration in hepatic ischemia/reperfusion injury.

BACKGROUND: Sevoflurane (Sevo) preconditioning and postconditioning play a protective role against injury induced by hepatic ischemia/reperfusion (I/R). At the same time, the involvement of macrophage infiltration in this process and the precise mechanisms are unclear. Here, we designed this research to elucidate the protective effects of Sevo against hepatic I/R injury and the molecules involved. METHODS: The alleviating effect of Sevo on the liver injury was analyzed by liver function analysis, hematoxylin and eosin staining, Masson trichrome staining, terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling, western blot analysis and an enzyme-linked immunosorbent assay. An in vitro cell model was developed using alpha mouse liver 12 (AML12) cells, and the cell model was treated with oxygen-glucose deprivation and reoxygenation and Sevo. Multiple bioinformatics databases were used to screen transcriptional regulators related to hepatic I/R injury and the targets of Krueppel-like factor 5 (KLF5). KLF5 expression was artificially upregulated alone or with integrin beta-2 (ITGB2) knockdown to substantiate their involvement in Sevo-mediated hepatoprotection. RESULTS: Sevo protected the liver against I/R injury by reducing cell apoptosis and inflammatory response. KLF5 was upregulated in liver tissues following I/R injury, whereas KLF5 overexpression aggravated macrophage infiltration and liver injury induced by I/R injury. KLF5 bound to the promoter of ITGB2 to enhance ITGB2 transcription. Knockdown of ITGB2 reversed the aggravation of injury caused by KLF5 overexpression in mice and AML12 cells. CONCLUSIONS: Sevo blocked KLF5-mediated transcriptional activation of ITGB2, thereby inhibiting macrophage infiltration in hepatic I/R injury.

Hyphal Als proteins act as CR3 ligands to promote immune responses against Candida albicans.

Patients with decreased levels of CD18 (ß2 integrins) suffer from life-threatening bacterial and fungal infections. CD11b, the α subunit of integrin CR3 (CD11b/CD18, αMß2), is essential for mice to fight against systemic Candida albicans infections. Live elongating C. albicans activates CR3 in immune cells. However, the hyphal ligands that activate CR3 are not well defined. Here, we discovered that the C. albicans Als family proteins are recognized by the I domain of CD11b in macrophages. This recognition synergizes with the ß-glucan-bound lectin-like domain to activate CR3, thereby promoting Syk signaling and inflammasome activation. Dectin-2 activation serves as the "outside-in signaling" for CR3 activation at the entry site of incompletely sealed phagosomes, where a thick cuff of F-actin forms to strengthen the local interaction. In vitro, CD18 partially contributes to IL-1ß release from dendritic cells induced by purified hyphal Als3. In vivo, Als3 is vital for C. albicans clearance in mouse kidneys. These findings uncover a novel family of ligands for the CR3 I domain that promotes fungal clearance.

Analysis of Clinical, Immunological and Molecular Features of Leukocyte Adhesion Deficiency Type I in Egyptian Children.

PURPOSE: Leukocyte adhesion deficiency (LAD) represents a rare group of inherited inborn errors of immunity (IEI) characterized by bacterial infections, delayed umbilical stump separation, and autoimmunity. This single-center study aimed at describing the clinical, immunological, and molecular characterizations of 34 LAD-I Egyptian pediatric patients. METHODS: Details of 34 patients' personal medical history, clinical and laboratory findings were recorded; Genetic material from 28 patients was studied. Mutational analysis was done by Sanger sequencing. RESULTS: Omphalitis, skin and soft tissue infections with poorly healing ulcers, delayed falling of the umbilical stump, and recurrent or un-resolving pneumonia were the most common presentations, followed by chronic otitis media, enteropathy, periodontitis; and recurrent oral thrush. Persistent leukocytosis and neutrophilia were reported in all patients, as well as CD18 and CD11b deficiency. CD18 expression was < 2% in around 90% of patients. Sixteen different pathological gene variants were detected in 28 patients who underwent ITGß2 gene sequencing, of those, ten were novel and six were previously reported. Three families received a prenatal diagnosis. Patients were on antimicrobials according to culture's results whenever available, and on prophylactic Trimethoprim-Sulfamethoxazole 5 mg/kg once daily, with regular clinical follow up. Hematopoietic stem cell transplantation (HSCT) was offered for 4 patients. However due to severity of the disease and delay in diagnosis, 58% of the patients passed away in the first 2 years of life. CONCLUSION: This study highlights the importance of early diagnosis and distribution of ITGß2 gene mutation in Egyptian children. Further molecular studies, however, remain a challenging necessity for better disease characterization in the region.

Gigantol ameliorates DSS-induced colitis via suppressing ß2 integrin mediated adhesion and chemotaxis of macrophage.

ETHNOPHARMACOLOGICAL RELEVANCE: Dendrobium, recognized as "Shihu" in traditional Chinese medicine, holds a rich history of medicinal utilization documented in the Chinese Pharmacopoeia. Ancient texts like "Shen Nong Ben Cao Jing" extol Dendrobium's virtues as a superior herbal medicine fortifying "Yin" and invigorating the five viscera. Dendrobium is extensively employed for the treatment of gastrointestinal inflammatory disorders, showcasing significant therapeutic efficacy, particularly against ulcerative colitis (UC), within the realm of Chinese ethnopharmacology. Dendrobium plays crucial pharmacological roles due to its rich content of polysaccharides, alkaloids, phenanthrenes, and bibenzyls. Gigantol, a prominent bibenzyl compound, stands out as one of the most vital active constituents within Dendrobium, the gigantol content of Dendrobium leaves can reach approximately 4.79 µg/g. Its significance lies in being recognized as a noteworthy anti-inflammatory compound derived from Dendrobium. AIM OF THE STUDY: Given the pivotal role of gigantol as a primary active substance in Dendrobium, the therapeutic potential of gigantol for gastrointestinal diseases remains enigmatic. Our present investigation aimed to evaluate the therapeutic effects of gigantol on dextran sulfate sodium (DSS)-induced colitis and reveal its potential mechanism in countering UC activity. MATERIALS AND METHODS: The protective efficacy of gigantol against colitis was assessed by examining the histopathological changes and conducting biochemical analyses of colon from DSS-challenged mice. Assessments focused on gigantol's impact on improving the intestinal epithelial barrier and its anti-inflammatory effects in colonic tissues of colitis mice. Investigative techniques included the exploration of the macrophage inflammatory signaling pathway via qPCR and Western blot analyses. In vitro studies scrutinized macrophage adhesion, migration, and chemotaxis utilizing transwell and Zigmond chambers. Furthermore, F-actin and Rac1 activation assays detailed cellular cytoskeletal remodeling. The potential therapeutic target of gigantol was identified and validated through protein binding analysis, competitive enzyme-linked immunosorbent assay (ELISA), cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS) assay. The binding sites between gigantol and its target were predicted via molecular docking. RESULTS: Gigantol ameliorated symptoms of DSS-induced colitis, rectified damage to the intestinal barrier, and suppressed the production of pro-inflammatory cytokines in colonic tissues. Intriguingly, gigantol significantly curtailed NF-κB signaling activation in the colons of DSS-induced colitis mice. Notably, gigantol impaired the ß2 integrin-dependent adhesion and migratory capacity of RAW264.7 cells. Moreover, gigantol notably influenced the cytoskeleton remodeling of RAW264.7 cells by suppressing Vav1 phosphorylation and Rac1 activation. Mechanistically, gigantol interacted with ß2 integrin, subsequently diminishing binding affinity with intercellular adhesion molecule-1 (ICAM-1). CONCLUSIONS: In conclusion, these findings elucidate that gigantol ameliorates DSS-induced colitis by antagonizing ß2 integrin-mediated macrophage adhesion, migration, and chemotaxis, thus it may impede macrophage recruitment and infiltration into colonic tissues. This study suggests that gigantol shows promise as a viable candidate for clinical colitis therapy.

The extracellular cyclophilin A-integrin ß2 complex as a therapeutic target of viral pneumonia.

The acute respiratory virus infection can induce uncontrolled inflammatory responses, such as cytokine storm and viral pneumonia, which are the major causes of death in clinical cases. Cyclophilin A (CypA) is mainly distributed in the cytoplasm of resting cells and released into the extracellular space in response to inflammatory stimuli. Extracellular CypA (eCypA) is upregulated and promotes inflammatory response in severe COVID-19 patients. However, how eCypA promotes virus-induced inflammatory response remains elusive. Here, we observe that eCypA is induced by influenza A and B viruses and SARS-CoV-2 in cells, mice, or patients. Anti-CypA mAb reduces pro-inflammatory cytokines production, leukocytes infiltration, and lung injury in virus-infected mice. Mechanistically, eCypA binding to integrin ß2 triggers integrin activation, thereby facilitating leukocyte trafficking and cytokines production via the focal adhesion kinase (FAK)/GTPase and FAK/ERK/P65 pathways, respectively. These functions are suppressed by the anti-CypA mAb that specifically blocks eCypA-integrin ß2 interaction. Overall, our findings reveal that eCypA-integrin ß2 signaling mediates virus-induced inflammatory response, indicating that eCypA is a potential target for antibody therapy against viral pneumonia.

SKAP2 acts downstream of CD11b/CD18 and regulates neutrophil effector function.

Background: The importance of CD11b/CD18 expression in neutrophil effector functions is well known. Beyond KINDLIN3 and TALIN1, which are involved in the induction of the high-affinity binding CD11b/CD18 conformation, the signaling pathways that orchestrate this response remain incompletely understood. Method: We performed an unbiased screening method for protein selection by biotin identification (BioID) and investigated the KINDLIN3 interactome. We used liquid chromatography with tandem mass spectrometry as a powerful analytical tool. Generation of NB4 CD18, KINDLIN3, or SKAP2 knockout neutrophils was achieved using CRISPR-Cas9 technology, and the cells were examined for their effector function using flow cytometry, live cell imaging, microscopy, adhesion, or antibody-dependent cellular cytotoxicity (ADCC). Results: Among the 325 proteins significantly enriched, we identified Src kinase-associated phosphoprotein 2 (SKAP2), a protein involved in actin polymerization and integrin-mediated outside-in signaling. CD18 immunoprecipitation in primary or NB4 neutrophils demonstrated the presence of SKAP2 in the CD11b/CD18 complex at a steady state. Under this condition, adhesion to plastic, ICAM-1, or fibronectin was observed in the absence of SKAP2, which could be abrogated by blocking the actin rearrangements with latrunculin B. Upon stimulation of NB4 SKAP2-deficient neutrophils, adhesion to fibronectin was enhanced whereas CD18 clustering was strongly reduced. This response corresponded with significantly impaired CD11b/CD18-dependent NADPH oxidase activity, phagocytosis, and cytotoxicity against tumor cells. Conclusion: Our results suggest that SKAP2 has a dual role. It may restrict CD11b/CD18-mediated adhesion only under resting conditions, but its major contribution lies in the regulation of dynamic CD11b/CD18-mediated actin rearrangements and clustering as required for cellular effector functions of human neutrophils.

Identifying critical genes and pathways of doxorubicin-induced cardiomyopathy via bioinformatics analysis.

OBJECTIVE: The pathogenesis of doxorubicin (DOX) induced cardiomyopathy (DCM) is still uncertain. We aimed to identify the critical genes and pathways involved in DCM based on bioinformatics analysis. MATERIALS AND METHODS: The GSE59672 and GSE23598 mice heart tissue microarray data were obtained from Gene Expression Omnibus (GEO) database. The "limma" package of R software was used to screen the differently expressed genes (DEGs). GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses were performed on DEGs by using "clusterProfiler" package in R software. The PPI (Protein - Protein Interaction) network of DEGs constructed by STRING online database and thereby the top 15 hub genes selected by cytoHubba in Cytoscape software. The hub genes interaction was performed by GeneMANIA online database. The "Corrplot" R package was employed to assess hub genes correlation. RESULTS: Finally, a total of 492 and 501 DEGs were screened in GSE59672 and GSE23598 datasets, respectively. GO analyses revealed that DEGs were mainly involved in the regulation of extracellular matrix organization, metabolic process, regulation of collagen-containing extracellular matrix. KEGG pathway analyses indicated that DEGs were mainly involved in protein digestion and absorption, ECM-receptor interaction, phagosome, and p53 signaling pathway. Finally, the 8 hub genes were identified, including Col1a1, Col3a1, Col1a2, Col6a1, Ptprc, Tyrobp, Itgb2, and Ctss. CONCLUSIONS: The present study identified a series of key genes, including Col1a1, Col3a1, Col1a2, Col6a1, Ptprc, Tyrobp, Itgb2, and Ctss. In addition, important pathways were also discovered. The results of this study may provide a novel molecular mechanism and potential therapeutic targets for DCM.

Dysregulation of LINC00324 promotes poor prognosis in patients with glioma.

BACKGROUND: LINC00324 is a long-stranded non-coding RNA, which is aberrantly expressed in various cancers and is associated with poor prognosis and clinical features. It involves multiple oncogenic molecular pathways affecting cell proliferation, migration, invasion, and apoptosis. However, the expression, function, and mechanism of LINC00324 in glioma have not been reported. MATERIAL AND METHODS: We assessed the expression of LINC00324 of LINC00324 in glioma patients based on data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) to identify pathways involved in LINC00324-related glioma pathogenesis. RESULTS: Based on our findings, we observed differential expression of LINC00324 between tumor and normal tissues in glioma patients. Our analysis of overall survival (OS) and disease-specific survival (DSS) indicated that glioma patients with high LINC00324 expression had a poorer prognosis compared to those with low LINC00324 expression. By integrating clinical data and genetic signatures from TCGA patients, we developed a nomogram to predict OS and DSS in glioma patients. Gene set enrichment analysis (GSEA) revealed that several pathways, including JAK/STAT3 signaling, epithelial-mesenchymal transition, STAT5 signaling, NF-κB activation, and apoptosis, were differentially enriched in glioma samples with high LINC00324 expression. Furthermore, we observed significant correlations between LINC00324 expression, immune infiltration levels, and expression of immune checkpoint-related genes (HAVCR2: r = 0.627, P = 1.54e-77; CD40: r = 0.604, P = 1.36e-70; ITGB2: r = 0.612, P = 6.33e-7; CX3CL1: r = -0.307, P = 9.24e-17). These findings highlight the potential significance of LINC00324 in glioma progression and suggest avenues for further research and potential therapeutic targets. CONCLUSION: Indeed, our results confirm that the LINC00324 signature holds promise as a prognostic predictor in glioma patients. This finding opens up new possibilities for understanding the disease and may offer valuable insights for the development of targeted therapies.

A Flow Cytometry-Based High-Throughput Technique for Screening Integrin-Inhibitory Drugs.

This protocol aims to establish a method for identifying small molecular antagonists of ß2 integrin activation, utilizing conformational-change-reporting antibodies and high-throughput flow cytometry. The method can also serve as a guide for other antibody-based high-throughput screening methods. ß2 integrins are leukocyte-specific adhesion molecules that are crucial in immune responses. Neutrophils rely on integrin activation to exit the bloodstream, not only to fight infections but also to be involved in multiple inflammatory diseases. Controlling ß2 integrin activation presents a viable approach for treating neutrophil-associated inflammatory diseases. In this protocol, a monoclonal antibody, mAb24, which specifically binds to the high-affinity headpiece of ß2 integrins, is utilized to quantify ß2 integrin activation on isolated primary human neutrophils. N-formylmethionyl-leucyl-phenylalanine (fMLP) is used as a stimulus to activate neutrophil ß2 integrins. A high-throughput flow cytometer capable of automatically running 384-well plate samples was used in this study. The effects of 320 chemicals on ß2 integrin inhibition are assessed within 3 h. Molecules that directly target ß2 integrins or target molecules in the G protein-coupled receptor-initiated integrin inside-out activation signaling pathway can be identified through this approach.

Treg-Related Genes Representing a Potential Shared Biological Mechanism Between Clear Cell Renal Carcinoma and Obesity.

OBJECTIVE: To determine the potential shared biological mechanism between obesity and clear cell renal carcinoma (ccRCC). STUDY DESIGN: Observational study. Place and Duration of the Study: Department of Urology, Lishui People's Hospital, Lishui City, China, from December 2022 to March 2023. METHODOLOGY: The test and validation cohorts were selected from the GEO database. WGCNA and PPI networks were applied to identify shared hub genes. GO/KEGG, GSEA, and ROC curve analyses were applied to explore the potential underlying mechanisms and diagnostic power. Logistic regression was used to select genes to construct the signature. The risk score and various immune-related analyses were performed to assess the clinical and immune performance of the signature. The CellMiner platform was used to screen potential FDA-approved drugs. RESULTS: PTPRC, TYROBP, ITGB2, CD86, and ITGAM were defined as shared hub genes with good diagnostic power for obesity and ccRCC. Eight immune cells exhibited a positive correlation with the hub genes, while two immune cells showed negative associations. MDSCs and Tregs had the strongest positive associations with the hub genes. The Treg-related pathway exhibited predominant enrichment. The TYROBP, ITGB2, and CD86 genes were selected to construct an immune signature that has good clinical and immune performance. Six FDA-approved drugs were screened. CONCLUSION: Five Treg-related genes were identified as shared hub genes in obese patients and ccRCC patients. A signature was constructed to describe the immune features of ccRCC. KEY WORDS: Treg-related genes, Shared biological mechanism, Immune signature, Obesity, Clear cell renal carcinoma (ccRCC).

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 ß2 integrin subfamily are composed of an alternative α (CD11a-d) subunit, which determines the specific receptor properties, and a constant ß (CD18) subunit. This review aims to present insight into the multiple immunological roles of integrin receptors, with a focus on ß2 integrins that are specifically expressed by leukocytes. The pathophysiological role of ß2 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 ß2 integrins in vivo employed mice with a constitutive knockout of all ß2 integrins or either family member, respectively, which complicated the differentiation between the direct and indirect effects of ß2 integrin deficiency for distinct cell types. The recent generation and characterization of transgenic mice with a cell-type-specific knockdown of ß2 integrins by our group has enabled the dissection of cell-specific roles of ß2 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 ß2 integrin activity for therapeutic applications.

ICAMs in Immunity, Intercellular Adhesion and Communication.

Interactions among leukocytes and leukocytes with immune-associated auxiliary cells represent an essential feature of the immune response that requires the involvement of cell adhesion molecules (CAMs). In the immune system, CAMs include a wide range of members pertaining to different structural and functional families involved in cell development, activation, differentiation and migration. Among them, ß2 integrins (LFA-1, Mac-1, p150,95 and αDß2) are predominantly involved in homotypic and heterotypic leukocyte adhesion. ß2 integrins bind to intercellular (I)CAMs, actin cytoskeleton-linked receptors belonging to immunoglobulin superfamily (IgSF)-CAMs expressed by leukocytes and vascular endothelial cells, enabling leukocyte activation and transendothelial migration. ß2 integrins have long been viewed as the most important ICAMs partners, propagating intracellular signalling from ß2 integrin-ICAM adhesion receptor interaction. In this review, we present previous evidence from pioneering studies and more recent findings supporting an important role for ICAMs in signal transduction. We also discuss the contribution of immune ICAMs (ICAM-1, -2, and -3) to reciprocal cell signalling and function in processes in which ß2 integrins supposedly take the lead, paying particular attention to T cell activation, differentiation and migration.

Identification of an association between coronary heart disease and ITGB2 methylation in peripheral blood by a case-control study.

BACKGROUND: Blood DNA methylation was associated with coronary heart disease (CHD) risk in Caucasians. We investigated the association between DNA methylation in peripheral blood at the reported loci and CHD in the Chinese population. METHODS: The integrin subunit beta 2 (ITGB2) gene was identified in 196 CHD cases and 184 controls, and its methylation level was determined by mass spectrometry. Logistic regression was used to assess the association. RESULTS: Hypomethylation of ITGB2 was significantly associated with heart failure CHD and NYHA Ⅰ&Ⅱ CHD patients with minor to medium cardiac function impairment (ITGB2_CpG_11/cg08422803, OR per -10 % methylation = 1.15 and 1.16; p = 0.012 and 0.018 by Bonferroni correction, respectively). Hypomethylation of ITGB2_CpG_11/cg08422803 was a risk factor for CHD in people < 65 years and males (p < 0.05 after Bonferroni correction). The combination of ITGB2 methylation and conventional CHD risk factors could efficiently discriminate CHD, heart failure CHD, NYHA I&II CHD, and myocardial infarction CHD patients from controls (AUC = 0.78, 0.81, 0.80, and 0.81, respectively). CONCLUSION: Blood-based ITGB2 methylation has the potential as a biomarker for CHD. The combination of ITGB2 methylation and conventional CHD risk factors may improve the risk assessment and detection of CHD.

Decreased toll-like receptor 4 and CD11b/CD18 expression on peripheral monocytes of hypertensive patients correlates with a lesser extent of endothelial damage: a preliminary study.

BACKGROUND: Low-grade chronic inflammation is recognized to contribute to the physiopathology of arterial hypertension. Therefore, this study aimed to assess the pro-inflammatory phenotype of peripheral monocytes of hypertensive patients by analyzing Toll-like receptor 4 (TLR4) and CD11b/CD18 surface expression. In the second part, the influence of phenotypic alterations of monocytes on the endothelial status reflected by circulating endothelial cells (CECs) was evaluated. PATIENTS: The study included 60 patients with arterial hypertension, who were divided into two subgroups based on the disease severity according to the applicable criteria. The mild hypertension and resistant hypertension groups included 30 patients each. The control group consisted of 33 normotensive volunteers matched for age and sex. RESULTS: Both in the entire group of patients and individual subgroups, reduced surface expression of TLR4 and CD11b/CD18 was found compared to normotensive volunteers. A reduced percentage of monocytes with the CD14 + TLR4 + immunophenotype was correlated with a lower MFI level of CD18 and CD11b in the entire group of patients and after division only in the mild hypertension group. Reduced surface expression of TLR4 in hypertensive patients correlated with a lower number of CECs. This relationship was not observed in the resistant hypertension group; instead, an independent effect of reduced CD11b/CD18 expression on the reduction of CEC number was demonstrated. CONCLUSION: Our preliminary study showed for the first time that hypertension of varying severity is accompanied by phenotypic changes in monocytes, manifested by reduced surface expression of both TLR4 and CD11b/CD18. These phenotypic changes were associated with a reduced degree of endothelial injury. Our study opens a new, unexplored area of research on the protective features of peripheral monocytes in hypertension.

The Rac-GEF Tiam1 controls integrin-dependent neutrophil responses.

Rac GTPases are required for neutrophil adhesion and migration, and for the neutrophil effector responses that kill pathogens. These Rac-dependent functions are impaired when neutrophils lack the activators of Rac, Rac-GEFs from the Prex, Vav, and Dock families. In this study, we demonstrate that Tiam1 is also expressed in neutrophils, governing focal complexes, actin cytoskeletal dynamics, polarisation, and migration, in a manner depending on the integrin ligand to which the cells adhere. Tiam1 is dispensable for the generation of reactive oxygen species but mediates degranulation and NETs release in adherent neutrophils, as well as the killing of bacteria. In vivo, Tiam1 is required for neutrophil recruitment during aseptic peritonitis and for the clearance of Streptococcus pneumoniae during pulmonary infection. However, Tiam1 functions differently to other Rac-GEFs. Instead of promoting neutrophil adhesion to ICAM1 and stimulating ß2 integrin activity as could be expected, Tiam1 restricts these processes. In accordance with these paradoxical inhibitory roles, Tiam1 limits the fMLP-stimulated activation of Rac1 and Rac2 in adherent neutrophils, rather than activating Rac as expected. Tiam1 promotes the expression of several regulators of small GTPases and cytoskeletal dynamics, including αPix, Psd4, Rasa3, and Tiam2. It also controls the association of Rasa3, and potentially αPix, Git2, Psd4, and 14-3-3ζ/δ, with Rac. We propose these latter roles of Tiam1 underlie its effects on Rac and ß2 integrin activity and on cell responses. Hence, Tiam1 is a novel regulator of Rac-dependent neutrophil responses that functions differently to other known neutrophil Rac-GEFs.

Comprehensive analyses for the coagulation and macrophage-related genes to reveal their joint roles in the prognosis and immunotherapy of lung adenocarcinoma patients.

Purpose: This study aims to explore novel biomarkers related to the coagulation process and tumor-associated macrophage (TAM) infiltration in lung adenocarcinoma (LUAD). Methods: The macrophage M2-related genes were obtained by Weighted Gene Co-expression Network Analysis (WGCNA) in bulk RNA-seq data, while the TAM marker genes were identified by analyzing the scRNA-seq data, and the coagulation-associated genes were obtained from MSigDB and KEGG databases. Survival analysis was performed for the intersectional genes. A risk score model was subsequently constructed based on the survival-related genes for prognosis prediction and validated in external datasets. Results: In total, 33 coagulation and macrophage-related (COMAR) genes were obtained, 19 of which were selected for the risk score model construction. Finally, 10 survival-associated genes (APOE, ARRB2, C1QB, F13A1, FCGR2A, FYN, ITGB2, MMP9, OLR1, and VSIG4) were involved in the COMAR risk score model. According to the risk score, patients were equally divided into low- and high-risk groups, and the prognosis of patients in the high-risk group was significantly worse than that in the low-risk group. The ROC curve indicated that the risk score model had high sensitivity and specificity, which was validated in multiple external datasets. Moreover, the model also had high efficacy in predicting the clinical outcomes of LUAD patients who received anti-PD-1/PD-L1 immunotherapy. Conclusion: The COMAR risk score model constructed in this study has excellent predictive value for the prognosis and immunotherapeutic clinical outcomes of patients with LUAD, which provides potential biomarkers for the treatment and prognostic prediction.

Clinical manifestations and expression of CD18 to guide the diagnosis of leukocyte adhesion deficiency type 1: Mexico experience.

BACKGROUND: Leukocyte adhesion deficiency type 1 (LAD-1) is an inborn error of immunity characterized by a defect in leukocyte trafficking. METHODS: Patients with clinical suspicion of LAD-1 were referred to our institution. Complete blood count and flow cytometric analysis, to identify the expression of CD18, CD11b, and the lymphocyte population phenotyping, were performed, and statistical analysis was completed. RESULTS: We report clinical manifestations and immunological findings of six Mexican patients diagnosed with LAD-1. The diagnosis was based on typical clinical presentation, combined with laboratory demonstration of leukocytosis, and significant reduction or near absence of CD18 and its associated molecules CD11a, CD11b, and CD11c on leukocytes. We found atypical manifestations, not described in other countries, such as early-onset autoimmunity or infections caused by certain microorganisms. CONCLUSIONS: Patients with LAD-1 may present with atypical manifestations, making flow cytometry an indispensable tool to confirm the diagnosis. We present the first report of LAD-1 patients in a Latin American country.

Development of genomic phenotype and immunophenotype of acute respiratory distress syndrome using autophagy and metabolism-related genes.

Background: Distinguishing ARDS phenotypes is of great importance for its precise treatment. In the study, we attempted to ascertain its phenotypes based on metabolic and autophagy-related genes and infiltrated immune cells. Methods: Transcription datasets of ARDS patients were obtained from Gene expression omnibus (GEO), autophagy and metabolic-related genes were from the Human Autophagy Database and the GeneCards Database, respectively. Autophagy and metabolism-related differentially expressed genes (AMRDEGs) were further identified by machine learning and processed for constructing the nomogram and the risk prediction model. Functional enrichment analyses of differentially expressed genes were performed between high- and low-risk groups. According to the protein-protein interaction network, these hub genes closely linked to increased risk of ARDS were identified with CytoHubba. ssGSEA and CIBERSORT was applied to analyze the infiltration pattern of immune cells in ARDS. Afterwards, immunologically characterized and molecular phenotypes were constructed according to infiltrated immune cells and hub genes. Results: A total of 26 AMRDEGs were obtained, and CTSB and EEF2 were identified as crucial AMRDEGs. The predictive capability of the risk score, calculated based on the expression levels of CTSB and EEF2, was robust for ARDS in both the discovery cohort (AUC = 1) and the validation cohort (AUC = 0.826). The mean risk score was determined to be 2.231332, and based on this score, patients were classified into high-risk and low-risk groups. 371 differential genes in high- and low-risk groups were analyzed. ITGAM, TYROBP, ITGB2, SPI1, PLEK, FGR, MPO, S100A12, HCK, and MYC were identified as hub genes. A total of 12 infiltrated immune cells were differentially expressed and have correlations with hub genes. According to hub genes and implanted immune cells, ARDS patients were divided into two different molecular phenotypes (Group 1: n = 38; Group 2: n = 19) and two immune phenotypes (Cluster1: n = 22; Cluster2: n = 35), respectively. Conclusion: This study picked up hub genes of ARDS related to autophagy and metabolism and clustered ARDS patients into different molecular phenotypes and immunophenotypes, providing insights into the precision medicine of treating patients with ARDS.

Aminopeptidase N/CD13 Crosslinking Promotes the Activation and Membrane Expression of Integrin CD11b/CD18.

The ß2 integrin CD11b/CD18, also known as complement receptor 3 (CR3), and the moonlighting protein aminopeptidase N (CD13), are two myeloid immune receptors with overlapping activities: adhesion, migration, phagocytosis of opsonized particles, and respiratory burst induction. Given their common functions, shared physical location, and the fact that some receptors can activate a selection of integrins, we hypothesized that CD13 could induce CR3 activation through an inside-out signaling mechanism and possibly have an influence on its membrane expression. We revealed that crosslinking CD13 on the surface of human macrophages not only activates CR3 but also influences its membrane expression. Both phenomena are affected by inhibitors of Src, PLCγ, Syk, and actin polymerization. Additionally, after only 10 min at 37 °C, cells with crosslinked CD13 start secreting pro-inflammatory cytokines like interferons type 1 and 2, IL-12p70, and IL-17a. We integrated our data with a bioinformatic analysis to confirm the connection between these receptors and to suggest the signaling cascade linking them. Our findings expand the list of features of CD13 by adding the activation of a different receptor via inside-out signaling. This opens the possibility of studying the joint contribution of CD13 and CR3 in contexts where either receptor has a recognized role, such as the progression of some leukemias.