Inflammatory Immune Cells Research Articles

Inflammation balance in skeletal muscle damage and repair.

Responding to tissue injury, skeletal muscles undergo the tissue destruction and reconstruction accompanied with inflammation. The immune system recognizes the molecules released from or exposed on the damaged tissue. In the local minor tissue damage, tissue-resident macrophages sequester pro-inflammatory debris to prevent initiation of inflammation. In most cases of the skeletal muscle injury, however, a cascade of inflammation will be initiated through activation of local macrophages and mast cells and recruitment of immune cells from blood circulation to the injured site by recongnization of damage-associated molecular patterns (DAMPs) and activated complement system. During the inflammation, macrophages and neutrophils scavenge the tissue debris to release inflammatory cytokines and the latter stimulates myoblast fusion and vascularization to promote injured muscle repair. On the other hand, an abundance of released inflammatory cytokines and chemokines causes the profound hyper-inflammation and mobilization of immune cells to trigger a vicious cycle and lead to the cytokine storm. The cytokine storm results in the elevation of cytolytic and cytotoxic molecules and reactive oxygen species (ROS) in the damaged muscle to aggravates the tissue injury, including the healthy bystander tissue. Severe inflammation in the skeletal muscle can lead to rhabdomyolysis and cause sepsis-like systemic inflammation response syndrome (SIRS) and remote organ damage. Therefore, understanding more details on the involvement of inflammatory factors and immune cells in the skeletal muscle damage and repair can provide the new precise therapeutic strategies, including attenuation of the muscle damage and promotion of the muscle repair.

A NOVEL BISPECIFIC CD8 TREG MODULATOR TARGETING CYTOLYTIC CD8 REGULATORY T CELLS REDUCES PATHOGENIC CD4 T CELLS AND INFLAMMATION IN TRANSLATIONAL MODELS OF INTESTINAL AUTOIMMUNE AND INFLAMMATORY DISEASE

Abstract INTRODUCTION We have characterized a novel CD8 Treg network in autoimmune patient peripheral blood and tissues, in which a subset of cytolytic CD8 Treg eliminate pathogenic CD4 T cells, reducing inflammation and ameliorating disease in response to pathogenic CD4 T cell activation. We hypothesize that the CD8 Treg network is dysfunctional in patients with Celiac and Crohn’s disease, allowing pathogenic CD4 T cell expansion, the initiation of a cascade of inflammatory pathological consequences and the perpetuation of tissue destructive inflammation in Celiac disease and IBD. Here we demonstrate the use of bispecific CD8 Treg modulators that may have the potential to restore the elimination of pathogenic CD4 T cells in disease. METHODS CD8 Treg were cultured with autologous antigen presenting cells pulsed with gliadin peptides, and either primary autologous CD4 T cells or a target gliadin-responsive T cell line. Novel bispecific CD8 Treg Modulators were designed and evaluated for targeted binding by Octet and flow cytometry. The functional impact of CD8 Treg modulators was evaluated using flow cytometry, Incucyte, and supernatant analysis in PBMCs isolated from Celiac and Crohn’s disease patients. CD8 Treg Modulators were also tested using celiac patient duodenal tissue biopsies and in xenograft animal models of acute GVHD. RESULTS Activation of human CD8 Treg resulted in rapid cytolysis of pathogenic CD4 T cells as one mechanism of action. Upon the addition of CD8 Treg modulators, activation, and prevalence of CD8 Tregs increased along with the increase of degranulation and lytic molecules, and the death of antigen activated CD4 T cells. Following gliadin exposure of intestinal organoid cultures, in the presence of CD8 Treg modulators, CD8 Treg prevalence increased, coincident with the reduction of activated CD4 T cell and a decrease of epithelial cell death. The administration of CD8 Treg modulators in a humanized mouse model of acute graft versus host disease resulted in delayed onset and decreased severity of disease (based on clinical score and tissue pathology), and reduction of pro-inflammatory serum cytokines. CONCLUSION Our results indicate that CD8 Treg modulators activate CD8 Tregs in vitro, in vivo, and in human tissue resulting in decreased inflammation and amelioration of disease. Our data suggest that this network can be targeted by immune-modulating biologics to suppress pathogenic T cells to reduce disease severity & delay onset, as well as mitigate severity & frequency of flares in patients with Celiac disease and IBD. Figure 1. CD8 regulatory T cells (CD8 Treg) fail to eliminate pathogenic CD4 T cells in autoimmune disorders. CD8 Treg are responsible for eliminating pathogenic CD4 T cells when they become activated in response to an antigenic trigger. When successful, pathogenic CD4 T cells are eliminated, preventing their expansion and downstream inflammatory consequences, including plasmablast activation and autoantibody secretion, production of pro-inflammatory cytokines and chemokines, recruitment of inflammatory immune cells and bystander T cell activation. In autoimmunity, this surveillance process fails, resulting in inflammation and tissue damage. Figure 2. Mozart’s CD8 Treg Modulators delay disease onset and reduce severity of disease in xenograft models of acute GVHD. CD8 Treg, characterized by expression of inhibitory KIR checkpoint proteins, can prevent disease when mobilized (Figure 2A). NSG mice were injected once a week for 4 weeks (ending day 21) with 0.2mg/kg CD8 Treg modulators. Bispecific antibody like molecules directed against KIR and CD8 induce CD8 Treg mobilization in vivo resulting in reduced pathology, proinflammatory serum cytokines, and disease severity (Figure 2B). CD8 Treg modulators also delayed disease onset and enhanced survival (Figure 2C).

In vitro model of brain endothelial cell barrier reveals alterations induced by Plasmodium blood stage factors

Cerebral malaria (CM) is a severe neurological condition caused by Plasmodium falciparum. Disruption of the brain-blood barrier (BBB) is a key pathological event leading to brain edema and vascular leakage in both humans and in the mouse model of CM. Interactions of brain endothelial cells with infected red blood cells (iRBCs) and with circulating inflammatory mediators and immune cells contribute to BBB dysfunction in CM. Adjunctive therapies for CM aim at preserving the BBB to prevent neurologic deficits. Experimental animal and cellular models are essential to develop new therapeutic strategies. However, in mice, the disease develops rapidly, which offers a very narrow time window for testing the therapeutic potential of drugs acting in the BBB. Here, we establish a brain endothelial cell barrier whose disturbance can be monitored by several parameters. Using this system, we found that incubation with iRBCs and with extracellular particles (EPs) released by iRBCs changes endothelial cell morphology, decreases the tight junction protein zonula occludens-1 (ZO-1), increases the gene expression of the intercellular adhesion molecule 1 (ICAM-1), and induces a significant reduction in transendothelial electrical resistance (TEER) with increased permeability. We propose this in vitro experimental setup as a straightforward tool to investigate molecular interactions and pathways causing endothelial barrier dysfunction and to test compounds that may target BBB and be effective against CM. A pre-selection of the effective compounds that strengthen the resistance of the brain endothelial cell barrier to Plasmodium-induced blood factors in vitro may increase the likelihood of their efficacy in preclinical disease mouse models of CM and in subsequent clinical trials with patients.

Altered early immune response after fracture and traumatic brain injury.

Clinical and preclinical data suggest accelerated bone fracture healing in subjects with an additional traumatic brain injury (TBI). Mechanistically, altered metabolism and neuro-endocrine regulations have been shown to influence bone formation after combined fracture and TBI, thereby increasing the bone content in the fracture callus. However, the early inflammatory response towards fracture and TBI has not been investigated in detail so far. This is of great importance, since the early inflammatory phase of fracture healing is known to be essential for the initiation of downstream regenerative processes for adequate fracture repair. Therefore, we analyzed systemic and local inflammatory mediators and immune cells in mice which were exposed to fracture only or fracture + TBI 6h and 24h after injury. We found a dysregulated systemic immune response and significantly fewer neutrophils and mast cells locally in the fracture hematoma. Further, local CXCL10 expression was significantly decreased in the animals with combined trauma, which correlated significantly with the reduced mast cell numbers. Since mast cells and mast cell-derived CXCL10 have been shown to increase osteoclastogenesis, the reduced mast cell numbers might contribute to higher bone content in the fracture callus of fracture + TBI mice due to decreased callus remodeling.

Pathogenic Role of Adipose Tissue-Derived Mesenchymal Stem Cells in Obesity and Obesity-Related Inflammatory Diseases.

Adipose tissue-derived mesenchymal stem cells (ASCs) are adult stem cells, endowed with self-renewal, multipotent capacities, and immunomodulatory properties, as mesenchymal stem cells (MSCs) from other origins. However, in a pathological context, ASCs like MSCs can exhibit pro-inflammatory properties and attract inflammatory immune cells at their neighborhood. Subsequently, this creates an inflammatory microenvironment leading to ASCs' or MSCs' dysfunctions. One such example is given by obesity where adipogenesis is impaired and insulin resistance is initiated. These opposite properties have led to the classification of MSCs into two categories defined as pro-inflammatory ASC1 or anti-inflammatory ASC2, in which plasticity depends on the micro-environmental stimuli. The aim of this review is to (i) highlight the pathogenic role of ASCs during obesity and obesity-related inflammatory diseases, such as rheumatoid arthritis, multiple sclerosis, psoriasis, inflammatory bowel disease, and cancer; and (ii) describe some of the mechanisms leading to ASCs dysfunctions. Thus, the role of soluble factors, adhesion molecules; TLRs, Th17, and Th22 cells; γδ T cells; and immune checkpoint overexpression will be addressed.

Exercise and chronic kidney disease: potential mechanisms underlying the physiological benefits.

Increasing evidence indicates that exercise has beneficial effects on chronic inflammation, cardiorespiratory function, muscle and bone strength and metabolic markers in adults with chronic kidney disease (CKD), kidney failure or kidney transplants. However, the mechanisms that underlie these benefits have received little attention, and the available clinical evidence is mainly from small, short-duration (<12 weeks) exercise intervention studies. The available data, mainly from patients with CKD or on dialysis, suggest that exercise-mediated shifts towards a less inflammatory immune cell profile, enhanced activity of the NRF2 pathway and reduced monocyte infiltration into adipose tissue may underlie improvements in inflammatory biomarkers. Exercise-mediated increases in nitric oxide release and bioavailability, reduced angiotensin II accumulation in the heart, left ventricular remodelling and reductions in myocardial fibrosis may contribute to improvements in left ventricular hypertrophy. Exercise stimulates an anabolic response in skeletal muscle in CKD, but increases in mitochondrial mass and satellite cell activation seem to be impaired in this population. Exercise-mediated activation of the canonical wnt pathway may lead to bone formation and improvements in the levels of the bone-derived hormones klotho and fibroblast growth factor 23 (FGF23). Longer duration studies with larger sample sizes are needed to confirm these mechanisms in CKD, kidney failure and kidney transplant populations and provide evidence for targeted exercise interventions.

Manufactured tissue-to-tissue barrier chip for modeling the human blood-brain barrier and regulation of cellular trafficking.

Microphysiological system or organ-on-a-chip technologies can replicate the key structure and function of 3D human tissues with higher reproducibility than less controllable 3D cell aggregate models, providing great potential to become advanced drug toxicity and efficacy test platforms alternative to animal models. However, these organ chip models remain to be manufactured and standardized in a highly reproducible manner for reliable drug screening and mechanism of action research. Herein, we present a manufactured form of 'micro-engineered physiological system-tissue barrier chip' called MEPS-TBC for the highly replicable modeling of the human blood-brain barrier (BBB) with a 3D perivascular space. The perivascular region was controlled by tunable aspiration, where human astrocytes reside in 3D, create a network, and communicate with human pericytes facing human vascular endothelial cells, thereby replicating the 3D BBB. The lower channel structure of MEPS-TBC was designed and optimized using a computational simulation to facilitate aspiration while maintaining multicellular construction. Our human BBB model of the 3D perivascular unit and the endothelium perfused by physiological shear stress secured significantly enhanced barrier function exhibiting greater TEER and lower permeability, compared to the only endothelial model, indicating that the cellular interactions between BBB cells significantly contribute to the BBB formation. Importantly, our BBB model showed the cellular barrier function for homeostatic trafficking regulation against inflammatory peripheral immune cells, as well as for molecular transport control across the BBB. We believe our manufactured chip technology will construct reliable and standardized organ-chip models for disease mechanism research and predictive drug screening.

Coronary perivascular adipose tissue inflammation – An autopsy-based histomorphological study from a tertiary care hospital in South India

Background: The connective tissue around the blood vessels in the body (except cerebral vessels) is called perivascular adipose tissue (PVAT). Whenever there is a vascular pathology, PVAT increases in volume and becomes dysfunctional. This change promotes dedifferentiation of adipocytes. PVAT inflammation (PVATi) starts secreting anti-vasodilation and pro-inflammatory substance, leading to infiltration of inflammatory immune cells, endothelial dysfunction which initiates atherosclerosis followed by stenosis. It is now recognized that PVATi plays an important role in many vascular pathologies. Aims and Objectives: The objectives of the study were (1) to estimate the prevalence of coronary PVATi in an autopsy case, (2) to determine the coronary atherosclerotic changes and cardiac changes associated with PVATi, and (3) to correlate the association of PVATi with age and sex. Materials and Methods: Autopsy-based retrospective study done for a period of 1 year. From the autopsy requisition form, details such as age, gender, cause of death (COD), and gross findings of the organs were noted. The left coronary artery, right coronary artery, left anterior descending artery, left circumflex artery, and myocardium slides were reviewed microscopically to note the presence of PVATi, type of inflammatory infiltrate, atherosclerotic changes, percentage of stenosis, and associated cardiac changes. Range, frequencies, percentage, mean, standard deviation, and P-value were calculated. P&lt;0.05 was taken as statistically significant. Results: Fifty-two cases showed PVATi among 400 autopsy cases performed during the period of 1 year. Forty-two cases were from males and 10 cases were from female. The most common COD noted was sudden death following chest pain. Ten cases showed PVATi involving major branches of the coronary artery. Thirty-six cases showed hypertrophic changes in myocardium. Acute myocardial infarction (MI) and old healed MI were noted in 7 and 23 cases, respectively. Conclusion: PVATi of coronary arteries has significant association with atherosclerosis and sudden death cardiac death.

Definition of a novel breast tumor-specific classifier based on secretome analysis

BackgroundDuring cancer development, the normal tissue microenvironment is shaped by tumorigenic events. Inflammatory mediators and immune cells play a key role during this process. However, which molecular features most specifically characterize the malignant tissue remains poorly explored.MethodsWithin our institutional tumor microenvironment global analysis (T-MEGA) program, we set a prospective cohort of 422 untreated breast cancer patients. We established a dedicated pipeline to generate supernatants from tumor and juxta-tumor tissue explants and quantify 55 soluble molecules using Luminex or MSD. Those analytes belonged to five molecular families: chemokines, cytokines, growth factors, metalloproteinases, and adipokines.ResultsWhen looking at tissue specificity, our dataset revealed some breast tumor-specific characteristics, as IL-16, as well as some juxta-tumor-specific secreted molecules, as IL-33. Unsupervised clustering analysis identified groups of molecules that were specific to the breast tumor tissue and displayed a similar secretion behavior. We identified a tumor-specific cluster composed of nine molecules that were secreted fourteen times more in the tumor supernatants than the corresponding juxta-tumor supernatants. This cluster contained, among others, CCL17, CCL22, and CXCL9 and TGF-β1, 2, and 3. The systematic comparison of tumor and juxta-tumor secretome data allowed us to mathematically formalize a novel breast cancer signature composed of 14 molecules that segregated tumors from juxta-tumors, with a sensitivity of 96.8% and a specificity of 96%.ConclusionsOur study provides the first breast tumor-specific classifier computed on breast tissue-derived secretome data. Moreover, our T-MEGA cohort dataset is a freely accessible resource to the biomedical community to help advancing scientific knowledge on breast cancer.

Topical Skullcapflavone II attenuates atopic dermatitis in a mouse model by directly inhibiting associated cytokines in different cell types.

Skullcapflavone II (SFII), a flavonoid derived from Scutellaria baicalensis, is an anticancer agent. We aimed to validate SFII for atopic dermatitis (AD) therapy by demonstrating the anti-inflammatory effects of SFII in an AD mouse model produced by the topical application of the vitamin D3 analog MC903. We showed that topical treatment with SFII significantly suppressed MC903-induced serum IgE levels compared with topical hydrocortisone (HC) treatment. Topical SFII also prevents MC903-induced pruritus, skin hyperplasia, and inflammatory immune cell infiltration into lesional skin comparable to topical HC. In addition, MC903-induced immune cell chemoattractants and AD-associated cytokine production in skin lesions were effectively suppressed by topical SFII. The production of MC903-induced effector cytokines influencing T helper (Th)2 and Th17 polarization in lesioned skin is significantly inhibited by topical SFII. Furthermore, we showed that SFII can directly inhibit the production of AD-associated cytokines by human primary keratinocytes, mouse bone marrow-derived cells (BMDCs), and mouse CD4+ T cells in vitro. Lastly, we demonstrated that topical SFII more effectively suppressed serum IgE levels, the production of IL-4 and thymic stromal lymphopoietin (TSLP), and infiltration of CD4+ T cells and Gr-1+ cells (neutrophils) into lesion skin compared to topical baicalein (a flavonoid derived from Scutellaria baicalensis), which has anti-inflammatory effects. Taken together, our findings suggest that SFII may have promising therapeutic potential for this complex disease via the regulation of multiple AD-associated targets.

Advances in NURR1-Regulated Neuroinflammation Associated with Parkinson's Disease.

Neuroinflammation plays a crucial role in the progression of neurodegenerative disorders, particularly Parkinson's disease (PD). Glial cell activation and subsequent adaptive immune involvement are neuroinflammatory features in familial and idiopathic PD, resulting in the death of dopaminergic neuron cells. An oxidative stress response, inflammatory mediator production, and immune cell recruitment and activation are all hallmarks of this activation, leading to chronic neuroinflammation and progressive neurodegeneration. Several studies in PD patients' cerebrospinal fluid and peripheral blood revealed alterations in inflammatory markers and immune cell populations that may lead to or exacerbate neuroinflammation and perpetuate the neurodegenerative process. Most of the genes causing PD are also expressed in astrocytes and microglia, converting their neuroprotective role into a pathogenic one and contributing to disease onset and progression. Nuclear receptor-related transcription factor 1 (NURR1) regulates gene expression linked to dopaminergic neuron genesis and functional maintenance. In addition to playing a key role in developing and maintaining neurotransmitter phenotypes in dopaminergic neurons, NURR1 agonists have been shown to reverse behavioral and histological abnormalities in animal PD models. NURR1 protects dopaminergic neurons from inflammation-induced degeneration, specifically attenuating neuronal death by suppressing the expression of inflammatory genes in microglia and astrocytes. This narrative review highlights the inflammatory changes in PD and the advances in NURR1-regulated neuroinflammation associated with PD. Further, we present new evidence that targeting this inflammation with a variety of potential NURR1 target therapy medications can effectively slow the progression of chronic neuroinflammation-induced PD.

Gene Expression Profiling of Peripheral Blood Mononuclear Cells in Type 2 Diabetes: An Exploratory Study.

Background and Objectives: Visceral obesity is associated with chronic low-grade inflammation that predisposes to metabolic syndrome. Indeed, infiltration of adipose tissue with immune-inflammatory cells, including 'classical' inflammatory M1 and anti-inflammatory 'alternative' M2 macrophages, causes the release of a variety of bioactive molecules, resulting in the metabolic complications of obesity. This study examined the relative expression of macrophage phenotypic surface markers, cholesterol efflux proteins, scavenger receptors, and adenosine receptors in human circulating peripheral blood mononuclear cells (PBMCs), isolated from patients with type 2 diabetes mellitus (T2DM), with the aim to phenotypically characterize and identify biomarkers for these ill-defined cells. Materials and Methodology: PBMCs were isolated from four groups of adults: Normal-weight non-diabetic, obese non-diabetic, newly diagnosed with T2DM, and T2DM on metformin. The mRNA expression levels of macrophage phenotypic surface markers (interleukin-12 (IL-12), C-X-C motif chemokine ligand 10 (CXCL10), C-C motif chemokine ligand 17 (CCL17), and C-C motif receptor 7 (CCR7)), cholesterol efflux proteins (ATP-binding cassette transporter-1 (ABCA1), ATP binding cassette subfamily G member 1 (ABCG1), and sterol 27-hydroxylase (CYP27A)), scavenger receptors (scavenger receptor-A (SR-A), C-X-C motif ligand 16 (CXCL16), and lectin-like oxidized LDL receptor-1 (LOX-1)), and adenosine receptors (adenosine A2A receptor (A2AR) and adenosine A3 receptor (A3R)) were measured using qRT-PCR. Results: In PBMCs from T2DM patients, the expression of IL-12, CCR7, ABCA1, and SR-A1 was increased, whereas the expression of CXCL10, CCL17, ABCG1,27-hydroxylase, LOX-1, A2AR and A3R was decreased. On the other hand, treatment with the antidiabetic drug, metformin, reduced the expression of IL-12 and increased the expression of 27-hydroxylase, LOX-1, CXCL16 and A2AR. Conclusions: PBMCs in the circulation of patients with T2DM express phenotypic markers that are different from those typically present in adipose tissue M1 and M2 macrophages and could be representative of metabolically activated macrophages (MMe)-like cells. Our findings suggest that metformin alters phenotypic markers of MMe-like cells in circulation.

Differential effects of Usutu and West Nile viruses on neuroinflammation, immune cell recruitment and blood–brain barrier integrity

ABSTRACT Usutu (USUV) and West Nile (WNV) viruses are two closely related Flavivirus belonging to Japanese encephalitis virus serogroup. Evidence of increased circulation of these two arboviruses now exist in Europe. Neurological disorders are reported in humans mainly for WNV, despite the fact that the interaction and effects of viral infections on the neurovasculature are poorly described, notably for USUV. Using a human in vitro blood–brain barrier (BBB) and a mouse model, this study characterizes and compares the cerebral endothelial cell permissiveness, innate immunity and inflammatory responses and immune cell recruitment during infection by USUV and WNV. Both viruses are able to infect and cross the human BBB but with different consequences. We observed that WNV infects BBB cells resulting in significant endothelium impairment, potent neuroinflammation and immune cell recruitment, in agreement with previous studies. USUV, despite being able to infect BBB cells with higher replication rate than WNV, does not strongly affect endothelium integrity. Importantly, USUV also induces neuroinflammation, immune cell recruitment such as T lymphocytes, monocytes and dendritic cells (DCs) and was able to infect dendritic cells (DCs) more efficiently compared to WNV, with greater propensity for BBB recruitment. DCs may have differential roles for neuroinvasion of the two related viruses.

Abstract IA014: SWI/SNF complexes in development and disease

Abstract The Hargreaves laboratory is focused on understanding the molecular mechanisms of SWI/SNF complex function in immune cell differentiation and response relating to cancer and inflammation. SWI/SNF complexes are broadly required for embryonic development and cellular differentiation. Mutations in SWI/SNF complex genes are observed in ~20% of human cancers and in a number of rare intellectual disability disorders. However, it remains unclear how SWI/SNF complexes mechanistically regulate cellular differentiation through complex targeting, engagement with transcription factors, and function in transcription. We approach these questions in immune cells by employing molecular and proteomic methods in conjunction with next-generation sequencing approaches with the ultimate goal of connecting the functions of specific SWI/SNF subunits to the regulation of specific gene networks important for inflammatory responses and immune cell differentiation. This approach has allowed us to reveal the role of the canonical BAF complex (cBAF) in the establishment and maintenance of epigenetic transitions that occur during cellular differentiation, including activation of cell type-specific enhancers and engagement of transcription factors. Further, we and others have identified a new variant, referred to as the noncanonical BAF (ncBAF) complex, which exhibits distinct modes of targeting, unique regulatory interactions, and specific function in inflammatory gene transcription (Ahmed, Gatchalian et al PNAS 2022). Following up on the identification of the ncBAF subunit Brd9 in a CRISPR genome wide screen for regulators of Foxp3 performed in collaboration with the Zheng lab at the Salk Institute, we performed sgRNA knockdown to identify the role of each of the three SWI/SNF complex variants (BAF, ncBAF, and PBAF) (Loo, Gatchalian et al Immunity 2020). We found that ncBAF positively regulates the expression of Foxp3, while PBAF complexes negatively regulate Foxp3. Using epigenomic and transcriptomic analysis in Tregs following knockdown or chemical degradation of BRD9, we found that BRD9 positively regulates Foxp3 expression and its target genes by stabilizing Foxp3 binding at BRD9/Foxp3 co-bound sites, including at the Foxp3 locus. In an MC38 colorectal cancer model, transfer of Brd9 deficient Tregs resulted in significantly slower tumor growth than control Tregs, with increased infiltration of IFN-γ producing CD8 and CD4 T cells, suggesting that Brd9 deletion in Tregs reduces Treg-mediated suppression of anti-tumor responses. Thus, these results highlight BRD9 and the ncBAF complex as novel targets that could be exploited to manipulate Treg function in cancer. Citation Format: Jovylyn Gatchalian, Nasiha Ahmed, Chin-San Loo, Ye Zheng, Diana C. Hargreaves. SWI/SNF complexes in development and disease. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr IA014.

Characterizing Macrophages Diversity in COVID-19 Patients Using Deep Learning.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent responsible for coronavirus disease 2019 (COVID-19), has affected the lives of billions and killed millions of infected people. This virus has been demonstrated to have different outcomes among individuals, with some of them presenting a mild infection, while others present severe symptoms or even death. The identification of the molecular states related to the severity of a COVID-19 infection has become of the utmost importance to understanding the differences in critical immune response. In this study, we computationally processed a set of publicly available single-cell RNA-Seq (scRNA-Seq) data of 12 Bronchoalveolar Lavage Fluid (BALF) samples diagnosed as having a mild, severe, or no infection, and generated a high-quality dataset that consists of 63,734 cells, each with 23,916 genes. We extended the cell-type and sub-type composition identification and our analysis showed significant differences in cell-type composition in mild and severe groups compared to the normal. Importantly, inflammatory responses were dramatically elevated in the severe group, which was evidenced by the significant increase in macrophages, from 10.56% in the normal group to 20.97% in the mild group and 34.15% in the severe group. As an indicator of immune defense, populations of T cells accounted for 24.76% in the mild group and decreased to 7.35% in the severe group. To verify these findings, we developed several artificial neural networks (ANNs) and graph convolutional neural network (GCNN) models. We showed that the GCNN models reach a prediction accuracy of the infection of 91.16% using data from subtypes of macrophages. Overall, our study indicates significant differences in the gene expression profiles of inflammatory response and immune cells of severely infected patients.

Pan-Cancer analysis of TERT and Validation in Osteosarcoma Cell Lines

PurposeTo investigate the possible functions of TERT in pan-cancer and OS. MethodsFirst, differential TERT gene expression analysis was conducted using multi-omics data integrative analyses, including differential expression, prognosis, the correlation between infiltrating inflammatory immune cells, and mutation in pan-cancer. Furthermore, differential TERT gene expression analysis was conducted using mRNA expression profiles related to OS based on the GEO Datasets. Various differentially expressed genes were chosen based on a fitness threshold for further investigations. Finally, the function of the TERT gene was assessed in OS cells, including cellular proliferation, migration, and metastasis. ResultsPan-cancer research demonstrated that variable expression of TERT was not only associated with numerous types of human cancer but was also intimately linked to DNA methylation. Bioinformatic investigation revealed a link between the differential expression of TERT with immune cell infiltration in the tumor microenvironment (TME). In vitro studies indicated that inhibition of TERT decreased OS cell proliferation, motility, and metastasis. ConclusionTERT may serve as a useful genomic biomarker for the diagnosis and prediction of pan-cancer and as a prospective therapeutic target for the treatment of OS.

Filoviruses: Innate Immunity, Inflammatory Cell Death, and Cytokines.

Filoviruses are a group of single-stranded negative sense RNA viruses. The most well-known filoviruses that affect humans are ebolaviruses and marburgviruses. During infection, they can cause life-threatening symptoms such as inflammation, tissue damage, and hemorrhagic fever, with case fatality rates as high as 90%. The innate immune system is the first line of defense against pathogenic insults such as filoviruses. Pattern recognition receptors (PRRs), including toll-like receptors, retinoic acid-inducible gene-I-like receptors, C-type lectin receptors, AIM2-like receptors, and NOD-like receptors, detect pathogens and activate downstream signaling to induce the production of proinflammatory cytokines and interferons, alert the surrounding cells to the threat, and clear infected and damaged cells through innate immune cell death. However, filoviruses can modulate the host inflammatory response and innate immune cell death, causing an aberrant immune reaction. Here, we discuss how the innate immune system senses invading filoviruses and how these deadly pathogens interfere with the immune response. Furthermore, we highlight the experimental difficulties of studying filoviruses as well as the current state of filovirus-targeting therapeutics.

Tolerogenic nanoparticles induce type II collagen-specific regulatory T cells and ameliorate osteoarthritis.

Local inflammation in the joint is considered to contribute to osteoarthritis (OA) progression. Here, we describe an immunomodulating nanoparticle for OA treatment. Intradermal injection of lipid nanoparticles (LNPs) loaded with type II collagen (Col II) and rapamycin (LNP-Col II-R) into OA mice effectively induced Col II-specific anti-inflammatory regulatory T cells, substantially increased anti-inflammatory cytokine expression, and reduced inflammatory immune cells and proinflammatory cytokine expression in the joints. Consequently, LNP-Col II-R injection inhibited chondrocyte apoptosis and cartilage matrix degradation and relieved pain, while injection of LNPs loaded with a control peptide and rapamycin did not induce these events. Adoptive transfer of CD4+CD25+ T cells isolated from LNP-Col II-R-injected mice suggested that Tregs induced by LNP-Col II-R injection were likely responsible for the therapeutic effects. Collectively, this study suggests nanoparticle-mediated immunomodulation in the joint as a simple and effective treatment for OA.

Neutrophil extracellular traps and complications of liver transplantation.

Many end-stage liver disease etiologies are attributed to robust inflammatory cell recruitment. Neutrophils play an important role in inflammatory infiltration and neutrophil phagocytosis, oxidative burst, and degranulation. It has also been suggested that neutrophils may release neutrophil extracellular traps (NETs) to kill pathogens. It has been proven that neutrophil infiltration within the liver contributes to an inflammatory microenvironment and immune cell activation. Growing evidence implies that NETs are involved in the progression of numerous complications of liver transplantation, including ischemia-reperfusion injury, acute rejection, thrombosis, and hepatocellular carcinoma recurrence. NETs are discussed in this comprehensive review, focusing on their effects on liver transplantation complications. Furthermore, we discuss NETs as potential targets for liver transplantation therapy.

Acid-sensitive ion channel 1a regulates TNF-α expression in LPS-induced acute lung injury via ERS-CHOP-C/EBPα signaling pathway

BackgroundAcute lung injury (ALI) is the local inflammatory response of the lungs involved in a variety of inflammatory cells. Macrophages are immune cells and inflammatory cells widely distributed in the body. Acid-sensitive ion channel 1a (ASIC1a) is involved in the occurrence of ALI, but the mechanism is still unclear. MethodsKunming mouse were stimulated by Lipopolysaccharides (LPS) to establish ALI model in vivo, and RAW264.7 cells were stimulated by LPS to establish inflammatory model in vitro. Amiloride was used as a blocker of ASIC1a to treat mice, and dexamethasone was used as a positive drug for ALI. After blockers and RNAi blocked or silenced the expression of ASIC1a, the expressions of ASIC1a, endoplasmic reticulum-related proteins GRP78, CHOP, C/EBPα and TNF-α were detected. The Ca2+ concentration was measured by a laser confocal microscope. The interaction between CHOP and C/EBPα and the effect of C/EBPα on the activity of TNF-α promoter were detected by immunoprecipitation and luciferase reporter. ResultsThe expressions of ASIC1a and TNF-α were increased significantly in LPS group. After the blocker and RNAi blocked or silenced ASIC1a, the expressions of TNF-α, GRP78, CHOP were reduced, and the intracellular Ca2+ influx was weakened. The results of immunoprecipitation showed that CHOP and C/EBPα interacted in the macrophages. After silencing CHOP, C/EBPα expression was increased, and TNF-α expression was decreased. The results of the luciferase reporter indicated that C/EBPα directly binds to TNF-α. ConclusionASIC1a regulates the expression of TNF-α in LPS-induced acute lung injury via ERS-CHOP-C/EBPα signaling pathway.