Pro-inflammatory Immune Response Research Articles

Immune response to viscerotropic Leishmania: a comprehensive review

L. donovani and L. infantum infections are associated with a broad clinical spectrum, ranging from asymptomatic cases to visceral leishmaniasis (VL) with high mortality rates. Clinical manifestations such as post-kala-azar dermal leishmaniasis (PKDL) and visceral leishmaniasis-associated hemophagocytic lymphohistiocytosis-mimic (VL-associated HLH-mimic) further contribute to the diversity of clinical manifestations. These clinical variations are intricately influenced by the complex interplay between the host’s immune response and the parasite’s escape mechanisms. This narrative review aims to elucidate the underlying immunological mechanisms associated with each clinical manifestation, drawing from published literature within the last 5 years. Specific attention is directed toward viscerotropic Leishmania sinfection in patients with inborn errors of immunity and acquired immunodeficiencies. In VL, parasites exploit various immune evasion mechanisms, including immune checkpoints, leading to a predominantly anti-inflammatory environment that favors parasite survival. Conversely, nearly 70% of individuals are capable of mounting an effective pro-inflammatory immune response, forming granulomas that contain the parasites. Despite this, some patients may experience reactivation of the disease upon immunosuppression, challenging current understandings of parasite eradication. Individuals living with HIV and those with inborn errors of immunity present a more severe course of infection, often with higher relapse rates. Therefore, it is crucial to exclude both primary and acquired immune deficiencies in patients presenting disease relapse and VL-associated HLH-mimic. The distinction between VL and HLH can be challenging due to clinical similarities, suggesting that the nosological entity known as VL-associated HLH may represent a severe presentation of symptomatic VL and it should be considered more accurate referring to this condition as VL-associated HLH-mimic. Consequently, excluding VL in patients presenting with HLH is essential, as appropriate antimicrobial therapy can reverse immune dysregulation. A comprehensive understanding of the immune-host interaction underlying Leishmania infection is crucial for formulating effective treatment and preventive strategies to mitigate the disease burden.

Cholesterol Efflux Decreases TLR4-Target Gene Expression in Cultured Macrophages Exposed to T. brucei Ghosts.

Trypanosoma brucei causes African trypanosomiasis in humans. Infection with T. brucei elicits a potent pro-inflammatory immune response within infected human hosts, and this response is thought to at least be partially due to Toll-like receptor (TLR) activation. In response to stimulation by lipopolysaccharide and other pathogen antigens, TLR4 translocates to lipid rafts, which induces the expression of pro-inflammatory genes. However, cholesterol efflux is acknowledged as anti-inflammatory due to promoting lipid raft disruption. In this study, we wanted to assess the impact of T. brucei "ghosts", which are non-viable T. brucei essentially devoid of intracellular contents, in stimulating macrophage TLR4 translocation to lipid rafts, and whether promoting cholesterol efflux in macrophages incubated with T. brucei ghosts attenuates TLR4-target gene expression. When cultured macrophages were exposed to T. brucei ghosts, we observed an increase in lipid raft TLR4 protein content, which suggests certain surface molecules of T. brucei serve as ligands for TLR4. However, pretreating macrophages with cholesterol acceptors before T. brucei ghost exposure decreased lipid raft TLR4 protein content and the expression of pro-inflammatory TLR4-target genes. Taken together, these results imply that macrophage cholesterol efflux weakens pro-inflammatory responses which occur from T. brucei infection via increasing macrophage lipid raft disruption.

Remote limb ischemic preconditioning alleviated spinal cord injury through inhibiting proinflammatory immune response and promoting the survival of spinal neurons.

Experimental animal study. To investigate the protective effect of remote limb ischemia preconditioning (RLPreC) on traumatic spinal cord injury (SCI) and explore the underlying biological mechanisms using RNA sequencing. China Rehabilitation Science Institute; Beijing; China. spinal cord injury was induced in mice using a force of 0.7 N. RLPreC treatment was administered. Motor function, pain behavior, and gene expression were assessed. RLPreC treatment significantly improved motor function and reduced pain-like behavior in SCI mice. RNA-Seq analysis identified 5247 differentially expressed genes (DEGs). GO analysis revealed enrichment of immune response, inflammatory signaling, and synaptic transmission pathways among these DEGs. KEGG analysis indicated suppression of inflammation and promotion of synapse-related pathways. RLPreC is a promising therapeutic strategy for improving motor function and alleviating pain after traumatic SCI. RNA-Seq analysis provides insights into potential therapeutic targets and warrants further investigation.

Lyme Arthritis: A 50-Year Journey.

Lyme arthritis (LA) was recognized as a separate entity in 1975 because of geographic clustering of children often diagnosed with juvenile rheumatoid arthritis in Lyme, Connecticut. After identification of erythema migrans as a common early feature of the illness, a prospective study of such patients implicated Ixodes scapularis ticks in disease transmission. In 1982, the causative agent, now called Borrelia burgdorferi, was cultured from these ticks and from Lyme disease patients. Subsequently, it was shown that LA could usually be treated successfully with oral antibiotics but sometimes required intravenous antibiotics. Yet, a small percentage of patients developed a dysregulated, proinflammatory immune response leading to persistent postinfectious synovitis with vascular damage, cytotoxic and autoimmune responses, and fibroblast proliferation, a lesion similar to that of rheumatoid arthritis. The message from postinfectious LA for other autoimmune arthritides is that a complex immune response with autoimmune features can begin with a microbial infection.

Controlling Alveolar Bone Loss by Hydrogel‐Based Mitigation of Oral Dysbiosis and Bacteria‐Triggered Proinflammatory Immune Response

AbstractPeriodontitis is a chronic infection where abnormal host‐microbiota interactions alter the oral microbiome, trigger a proinflammatory immune response, and cause inflammatory alveolar bone loss. While antibiotics are occasionally necessary for treating periodontitis, their use must be carefully managed to prevent the development of drug resistance and oral dysbiosis. Therefore, it's crucial to develop new treatment strategies for periodontitis that reduce antibiotic dependence while effectively controlling the inflammation triggered by bacteria. In this study, a hydrogel is engineered by grafting cationic polyamidoamine dendrimers (PAMAM‐G3) onto the oxidized carboxymethyl cellulose (OCMC) backbone, resulting in an injectable cationic hydrogel (OCMC‐PAMAM‐G3, O‐P). This hydrogel can capture anionic microbial‐associated molecular patterns (MAMPs), such as lipopolysaccharides (LPS) and cell‐free DNA (cfDNA). These findings reveal that using O‐P application circumvents the disruption of the oral mucosa microbiome caused by traditional antibiotics. Additionally, this hydrogel can mitigate inflammatory alveolar bone loss in a ligature‐induced periodontitis mouse model by alleviating the LPS/cfDNA‐TLR4/9 pathway. Moreover, topical administration of O‐P hydrogel has no significant adverse effects on the oral mucosa microbiome while improving the local subgingival microbiome. The study highlights a strategy targeting MAMPs while avoiding antibiotics, as it can mitigate the bacteria‐triggered proinflammatory immune response and potentially preserve oral dysbiosis.

Preclinical and Toxicology Assessment of ALW-II-41-27, an Inhibitor of the Eph Receptor A2 (EphA2).

The EphA2 receptor inhibitor ALW-II-41-27 has proven to be an effective in vitro antagonist of Pneumocystis β-glucan-induced proinflammatory signaling. This suggests its potential as a candidate for initial anti-inflammatory drug testing in the rodent model of Pneumocystis pneumonia (PCP). Initially, single-dose intraperitoneal (IP) injections of ALW-II-41-27 were administered at concentrations of 0, 10, 15, 20, and 30 mg/kg over a 24-h treatment period. Pharmacokinetics were assessed in plasma, bronchoalveolar lavage fluid (BALF), and epithelial lining fluid (ELF). Following these assessments, a final single mg/kg dosing was determined. Mice received daily IP injections of either vehicle or 20.0 mg/kg of ALW-II-41-27 for 10 days, with their weights recorded daily. On day 11, mice were weighed and euthanized. Lungs, liver, and kidneys were harvested for H&E staining and pathology scoring. Lung samples were further analyzed for proinflammatory cytokines using enzyme-linked immunosorbent assay (ELISA) and extracellular matrix production using quantitative PCR (qPCR). Postmortem blood collection was conducted for complete blood count (CBC) blood chemistry analysis. Lastly, ALW-II-41-27 was administered to mice prior to fungal β-glucans challenge to determine in vivo effects on lung inflammation. This report describes the PK assessment of ALW-II-41-27 given via IP in C57BL/6 mice. After PK data were generated, we tested ALW-II-41-27 at 20 mg/kg IP in mice and noted no significant changes in daily or final weight gain. ELISA results of proinflammatory cytokines from lung tissues showed no major differences in the respective groups. qPCR analysis of extracellular matrix transcripts were statistically similar. Examination and pathology scoring of H&E slides from lung, liver, and kidney in all groups and subsequent pathology scoring showed no significant toxicity. Blood chemistry and CBC analyses revealed no major abnormalities. Additionally, administering ALW-II-41-27 before intratracheal inoculation of fungal β-glucans, known to induce a strong proinflammatory response in the lungs, significantly reduced lung tissue IL-1β levels. In our initial general safety and toxicology assessments, ALW-II-41-27 displayed no inherent safety concerns in the analyzed parameters. These data support broader in vivo testing of the inhibitor as a timed adjunct therapy to the deleterious proinflammatory host immune response often associated with anti-Pneumocystis therapy.

Fibrous scaffolds loaded with BMSC-derived apoptotic vesicles promote wound healing by inducing macrophage polarization

Macrophages play a key role in wound healing. Dysfunction of their M0 polarization to M2 leads to disorders of the wound immune microenvironment and chronic inflammation, which affects wound healing. Regulating the polarization of M0 macrophages to M2 macrophages is an effective strategy for treating wound healing. Mesenchymal stem cells (MSCs) deliver endogenous regulatory factors via paracrine extracellular vesicles, which may play a key role in wound healing, and previous studies have shown that apoptotic bodies (ABs) are closely associated with inflammation regression and macrophage polarization. However, the specific regulatory mechanisms involved in ABs remain unknown. In the present study, we designed an MSC-AB (MSC-derived AB)-loaded polycaprolactone (PCL) scaffold, evaluated the macrophage phenotype and skin wound inflammation in vivo and in vitro, and explored the ability of MSC-AB-loaded PCL scaffolds to promote wound healing. Our data suggest that the PCL scaffold regulates the expression of the CCL-1 gene by targeting the delivery of mmu-miR-21a-5p by local sustained-release MSC-ABs, and drives M0 macrophages to program M2 macrophages to regulate inflammation and angiogenesis, thereby synergistically promoting wound healing. This study provides a promising therapeutic strategy and experimental basis for treating various diseases associated with imbalances in proinflammatory and anti-inflammatory immune responses.

Increased levels of regulatory T cells and IL-10-producing regulatory B cells are linked to improved clinical outcome in Parkinson's disease: a 1-year observational study.

Whilst the contribution of peripheral and central inflammation to neurodegeneration in Parkinson's disease and the role of the immune response in this disorder are well known, the effects of the anti-inflammatory response on the disease have not been described in depth. This study is aimed to assess the changes in the regulatory/inflammatory immune response in recently diagnosed, untreated PD patients and a year after. Twenty-one PD patients and 19 healthy controls were included and followed-up for 1 year. The levels of immunoregulatory cells (CD4+ Tregs, Bregs, and CD8+ Tregs); classical, nonclassical, and intermediate monocytes, and proinflammatory cells (Th1, Th2, and Th17) were measured by flow cytometry. Cytokine levels were determined by ELISA. Clinical follow-up was based on the Hoehn & Yahr and UDPRS scales. Our results indicate that the regulatory response in PD patients on follow-up was characterized by increased levels of active Tregs, functional Tregs, TR1, IL-10-producing functional Bregs, and IL-10-producing classical monocytes, along with decreased counts of Bregs and plasma cells. With respect to the proinflammatory immune response, peripheral levels of Th1 IFN-γ+ cells were decreased in treated PD patients, whilst the levels of CD4+ TBET+ cells, HLA-DR+ intermediate monocytes, IL-6, and IL-4 were increased after a 1-year follow-up. Our main finding was an increased regulatory T cell response after a 1-year follow-up and its link with clinical improvement in PD patients. In conclusion, aftera 1-year follow-up, PD patients exhibited increased levels of regulatory populations, which correlated with clinical improvement. However, a persistent inflammatory environment and active immune response were observed.

Vimentin regulates mitochondrial ROS production and inflammatory responses of neutrophils.

The intermediate filament vimentin is present in immune cells and is implicated in proinflammatory immune responses. Whether and how it supports antimicrobial activities of neutrophils are not well established. Here, we developed an immortalized neutrophil model to examine the requirement of vimentin. We demonstrate that vimentin restricts the production of proinflammatory cytokines and reactive oxygen species (ROS), but enhances phagocytosis and swarming. We observe that vimentin is dispensable for neutrophil extracellular trap (NET) formation, degranulation, and inflammasome activation. Moreover, gene expression analysis demonstrated that the presence of vimentin was associated with changes in expression of multiple genes required for mitochondrial function and ROS overproduction. Treatment of wild-type cells with rotenone, an inhibitor for complex I of the electron transport chain, increases the ROS levels. Likewise, treatment with mitoTEMPO, a SOD mimetic, rescues the ROS production in cells lacking vimentin. Together, these data show vimentin regulates neutrophil antimicrobial functions and alters ROS levels through regulation of mitochondrial activity.

Differential changes in end organ immune cells and inflammation in salt-sensitive hypertension: effects of increasing M2 macrophages.

Salt-sensitive hypertension (SSHTN) is associated with M1 macrophage polarization and inflammatory responses, leading to inflammation-associated lymphangiogenesis and functional impairment across multiple organs, including kidneys and gonads. However, it remains unclear whether promoting M2 macrophage polarization can alleviate the hypertension, inflammation, and end organ damage in mice with salt sensitive hypertension (SSHTN). Male and female mice were made hypertensive by administering nitro-L-arginine methyl ester hydrochloride (L-NAME; 0.5 mg/ml) for 2 weeks in the drinking water, followed by a 2-week interval without any treatments, and a subsequent high salt diet for 3 weeks (SSHTN). AVE0991 (AVE) was intraperitoneally administered concurrently with the high salt diet. Control mice were provided standard diet and tap water. AVE treatment significantly attenuated BP and inflammation in mice with SSHTN. Notably, AVE promoted M2 macrophage polarization, decreased pro-inflammatory immune cell populations, and improved function in renal and gonadal tissues of mice with SSHTN. Additionally, AVE decreased lymphangiogenesis in the kidneys and testes of male SSHTN mice and the ovaries of female SSHTN mice. These findings highlight the effectiveness of AVE in mitigating SSHTN-induced elevated BP, inflammation, and end organ damage by promoting M2 macrophage polarization and suppressing pro-inflammatory immune responses. Targeting macrophage polarization emerges as a promising therapeutic approach for alleviating inflammation and organ damage in SSHTN. Further studies are warranted to elucidate the precise mechanisms underlying AVE-mediated effects and to assess its clinical potential in managing SSHTN.

Association of HLA-DQ4/5 genotype polymorphisms with celiac disease in a group of children in Southwest Iran: A case-control study.

Celiac disease (CD) has proinflammatory and pathogenic immune responses to gluten in intestinal tissue, leading to structural changes in the mucosa of the small intestine. The association of human leukocyte antigen (HLA)-DQ2 and DQ8 genotypes with CD has been previously reported. This test has a negative predictive value close to 100%, so its main purpose is to rule out the detection of CD completely or almost completely. There is limited information regarding HLA-DQ4/5 in CD. This study was conducted to determine the HLA-DQ4/5 genotypes in a group of Southwestern Iranian children with CD. We conducted a case-control study in Southwest Iran involving 100 participants, employing a nonprobabilistic sampling method. Samples were taken from participants' oral buccal mucosa at Imam Sajjad Hospital of Yasuj, Iran. Then DNA was extracted from these samples and used to determine the frequency of HLA-DQ4/5 genotypes through Sequence-Specific Primer-Polymerase Chain Reaction assay. SPSS 20 was utilized for statistical analyses. Fifty diagnosed patients with CD (high anti-tissue transglutaminase [tTG]-IgA level [upper limit of normal] with pathological findings of Marsh III) and 50 non-CD individuals (normal anti-tTG-IgA level and normal total IgA level) were enrolled in the study from August 5, 2022 to October 15, 2023. Findings showed that the DQ4a*4b allele has the highest frequency in the CD samples (78%, p < 0.01) followed by the DQ5a*5b allele (12%, p < 0.01). Additionally, there was a higher prevalence of DQ4/DQ5 in patients with CD compared to controls (odds ratio = 6.5, confidence interval = 0.84 to 69.46, p < 0.01). Furthermore, a significant association was found among HLA DQ4/5 genotype, age (>9.5) (p < 0.01), and gender (female) (p < 0.05). The observed significant differences among HLA-DQ4 and HLA-DQ5 in Iranian CD samples against controls and the high value of the relative risks showed the significant function of the studied alleles in the prevalence of CD in Iranian patients.

Intranasal Vaccination with Recombinant TLR2-Active Outer Membrane Vesicles Containing Sequential M2e Epitopes Protects against Lethal Influenza a Challenge.

Influenza is a highly contagious respiratory disease, resulting in an estimated 3 to 5 million cases of severe illness annually. While most influenza vaccines are administered parenterally via injection, one shortcoming is that they do not generate a strong immune response at the site of infection, which can become important in a pandemic. Intranasal vaccines can generate both local and systemic protective immune responses, can reduce costs, and enhance ease of administration. Previous studies showed that parenterally administered outer membrane vesicles (OMVs) that carry sequences of the M2e protein (OMV-M2e) protect against influenza A/PR8 challenge in mice and ferrets. In the current study, we measured the effectiveness of the intranasal route of the OMV-M2e vaccine against the influenza A/PR8 strain in mice. We observed high anti-M2e IgG and IgA titers post-challenge in mice vaccinated intranasally with OMV-M2e. In addition, we observed a Th1/Tc1 bias in the vaccinated mice, and an increased Th17/Tc17 response, both of which correlated with survival to A/PR8 challenge and significantly lower lung viral titers. We conclude that the intranasal-route administration of the OMV-M2e vaccine is a promising approach toward generating protection against influenza A as it leads to an increased proinflammatory immune response correlating with survival to viral challenge.

Production and Release of Proinflammatory Mediators by the Cockroach Allergen Bla g 1 via a Shared Membrane-Destabilization Mechanism.

The cockroach allergen Bla g 1 encloses an exceptionally large hydrophobic cavity, which allows it to bind and deliver unsaturated fatty acid ligands. Bla g 1-mediated delivery of naturally occurring (nMix) ligands has been shown to destabilize lipid membranes, contributing to its digestive/antiviral functions within the source organism. However, the consequences of this activity on Bla g 1 allergenicity following human exposure remain unknown. In this work, we show that Bla g 1-mediated membrane disruption can induce a proinflammatory immune response in mammalian cells via two complementary pathways. At high concentrations, the cytotoxic activity of Bla g 1 induces the release of proinflammatory cytosolic contents including damage-associated molecular patterns (DAMPs) such as heat-shock Protein-70 (HSP70) and the cytokine interleukin-1 (IL-1β). Sublytic concentrations of Bla g 1 enhanced the ability of phospholipase A2 (PLA2) to extract and hydrolyze phospholipid substrates from cellular membranes, stimulating the production of free polyunsaturated fatty acids (PUFAs) and various downstream inflammatory lipid mediators. Both of these effects are dependent on the presence of Bla g 1's natural fatty-acid (nMix) ligands with CC50 values corresponding to the concentrations required for membrane destabilization reported in previous studies. Taken together, these results suggest that mechanisms through which Bla g 1-mediated lipid delivery and membrane destabilization could directly contribute to cockroach allergic sensitization.

Kinetics of pro- and anti-inflammatory spike-specific cellular immune responses in long-term care facility residents after COVID-19 mRNA primary and booster vaccination: a prospective longitudinal study in Japan

BackgroundThe magnitude and durability of cell-mediated immunity in older and severely frail individuals following coronavirus disease 2019 (COVID-19) vaccination remain unclear. A controlled immune response could be the key to preventing severe COVID-19; however, it is uncertain whether vaccination induces an anti-inflammatory cellular immune response. To address these issues, a 48-week-long prospective longitudinal study was conducted. A total of 106 infection-naive participants (57 long-term care facility [LTCF] residents [median age; 89.0 years], 28 outpatients [median age; 72.0 years], and 21 healthcare workers [median age; 51.0 years]) provided peripheral blood mononuclear cell (PBMC) samples for the assessment of spike-specific PBMC responses before primary vaccination, 24 weeks after primary vaccination, and three months after booster vaccination. Cellular immune responses to severe acute respiratory syndrome coronavirus 2 spike protein were examined by measuring interferon (IFN)-γ, tumor necrosis factor (TNF), interleukin (IL)-2, IL-4, IL-6, and IL-10 levels secreted from the spike protein peptide-stimulated PBMCs of participants.ResultsLTCF residents exhibited significantly lower IFN-γ, TNF, IL-2, and IL-6 levels than healthcare workers after the primary vaccination. Booster vaccination increased IL-2 and IL-6 levels in LTCF residents comparable to those in healthcare workers, whereas IFN-γ and TNF levels in LTCF residents remained significantly lower than those in healthcare workers. IL-10 levels were not significantly different from the initial values after primary vaccination but increased significantly after booster vaccination in all subgroups. Multivariate analysis showed that age was negatively associated with IFN-γ, TNF, IL-2, and IL-6 levels but not with IL-10 levels. The levels of pro-inflammatory cytokines, including IFN-γ, TNF, IL-2, and IL-6, were positively correlated with humoral immune responses, whereas IL-10 levels were not.ConclusionsOlder and severely frail individuals may exhibit diminished spike-specific PBMC responses following COVID-19 vaccination compared to the general population. A single booster vaccination may not adequately enhance cell-mediated immunity in older and severely frail individuals to a level comparable to that in the general population. Furthermore, booster vaccination may induce not only a pro-inflammatory cellular immune response but also an anti-inflammatory cellular immune response, potentially mitigating detrimental hyperinflammation.

Oral curcumin ameliorates acute murine campylobacteriosis

IntroductionHuman infections with the food-borne enteropathogen Campylobacter jejuni are responsible for increasing incidences of acute campylobacteriosis cases worldwide. Since antibiotic treatment is usually not indicated and the severity of the enteritis directly correlates with the risk of developing serious autoimmune disease later-on, novel antibiotics-independent intervention strategies with non-toxic compounds to ameliorate and even prevent campylobacteriosis are utmost wanted. Given its known pleiotropic health-promoting properties, curcumin constitutes such a promising candidate molecule. In our actual preclinical placebo-controlled intervention trial, we tested the anti-microbial and anti-inflammatory effects of oral curcumin pretreatment during acute experimental campylobacteriosis.MethodsTherefore, secondary abiotic IL-10-/- mice were challenged with synthetic curcumin via the drinking water starting a week prior oral C. jejuni infection. To assess anti-pathogenic, clinical, immune-modulatory, and functional effects of curcumin prophylaxis, gastrointestinal C. jejuni bacteria were cultured, clinical signs and colonic histopathological changes quantitated, pro-inflammatory immune cell responses determined by in situ immunohistochemistry and intestinal, extra-intestinal and systemic pro-inflammatory mediator measurements, and finally, intestinal epithelial barrier function tested by electrophysiological resistance analysis of colonic ex vivo biopsies in the Ussing chamber.Results and discussionWhereas placebo counterparts were suffering from severe enterocolitis characterized by wasting symptoms and bloody diarrhea on day 6 post-infection, curcumin pretreated mice, however, were clinically far less compromised and displayed less severe microscopic inflammatory sequelae such as histopathological changes and epithelial cell apoptosis in the colon. In addition, curcumin pretreatment could mitigate pro-inflammatory innate and adaptive immune responses in the intestinal tract and importantly, rescue colonic epithelial barrier integrity upon C. jejuni infection. Remarkably, the disease-mitigating effects of exogenous curcumin was also observed in organs beyond the infected intestines and strikingly, even systemically given basal hepatic, renal, and serum concentrations of pro-inflammatory mediators measured in curcumin pretreated mice on day 6 post-infection. In conclusion, the anti-Campylobacter and disease-mitigating including anti-inflammatory effects upon oral curcumin application observed here highlight the polyphenolic compound as a promising antibiotics-independent option for the prevention from severe acute campylobacteriosis and its potential post-infectious complications.

Statin administration or blocking PCSK9 alleviates airway hyperresponsiveness and lung fibrosis in high-fat diet-induced obese mice

BackgroundObesity is associated with airway hyperresponsiveness and lung fibrosis, which may reduce the effectiveness of standard asthma treatment in individuals suffering from both conditions. Statins and proprotein convertase subtilisin/kexin-9 inhibitors not only reduce serum cholesterol, free fatty acids but also diminish renin-angiotensin system activity and exhibit anti-inflammatory effects. These mechanisms may play a role in mitigating lung pathologies associated with obesity.MethodsMale C57BL/6 mice were induced to develop obesity through high-fat diet for 16 weeks. Conditional TGF-β1 transgenic mice were fed a normal diet. These mice were given either atorvastatin or proprotein convertase subtilisin/kexin-9 inhibitor (alirocumab), and the impact on airway hyperresponsiveness and lung pathologies was assessed.ResultsHigh-fat diet-induced obesity enhanced airway hyperresponsiveness, lung fibrosis, macrophages in bronchoalveolar lavage fluid, and pro-inflammatory mediators in the lung. These lipid-lowering agents attenuated airway hyperresponsiveness, macrophages in BALF, lung fibrosis, serum leptin, free fatty acids, TGF-β1, IL-1β, IL-6, and IL-17a in the lung. Furthermore, the increased RAS, NLRP3 inflammasome, and cholecystokinin in lung tissue of obese mice were reduced with statin or alirocumab. These agents also suppressed the pro-inflammatory immune responses and lung fibrosis in TGF-β1 over-expressed transgenic mice with normal diet.ConclusionsLipid-lowering treatment has the potential to alleviate obesity-induced airway hyperresponsiveness and lung fibrosis by inhibiting the NLRP3 inflammasome, RAS and cholecystokinin activity.Graphical abstract

Helminth alleviates COVID-19-related cytokine storm in an IL-9-dependent way.

Hyperactivation of pro-inflammatory type 1 cytokines (e.g., tumor necrosis factor alpha [TNF-α] and interferon gamma [IFN-γ]) mirrors the inflammation of coronavirus disease 2019. Helminths could alleviate excessive immune responses. Here, helminth Trichinella spiralis (Ts) infection was shown to protect against TNF-α- and IFN-γ-induced shock. Mechanistically, Ts-induced protection was interleukin-9 (IL-9) dependent but not IL-4Rα. Recombinant IL-9 treatment not only improved the survival of wild-type mice with TNF-α- and IFN-γ-induced shock but also that of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected K18-human angiotensin-converting enzyme 2 (hACE2) mice, emphasizing the significance of IL-9 in alleviating cytokine storm syndromes during SARS-CoV-2 infection. Interestingly, Ts excretory/secretory (TsES)-induced protection was also observed in SARS-CoV-2 infection, indicating that identifying anti-inflammatory molecules from TsES could be a novel way to mitigate adverse pathological inflammation during pathogen infection.IMPORTANCESevere coronavirus disease 2019 (COVID-19) is linked to cytokine storm triggered by type 1 pro-inflammatory immune responses. TNF-α and IFN-γ shock mirrors cytokine storm syndromes, including COVID-19. Helminths (e.g., Trichinella spiralis, Ts) can potently activate anti-inflammatory type 2 immune response. Here, we found that helminth Ts-induced protection against TNF-α and IFN-γ shock was IL-9 dependent. Treatment with recombinant IL-9 could protect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in K18-hACE2 mice. Helminth Ts excretory/secretory (TsES) products also ameliorated SARS-CoV-2 infection-related cytokine storm. In conclusion, our study emphasizes the significance of IL-9 in protecting from cytokine storm syndromes associated with SARS-CoV-2 infection. Anti-inflammatory molecules from TsES could be a new source to mitigate adverse pathological inflammation associated with infections, including COVID-19.

OV Modulators of the Paediatric Brain TIME: Current Status, Combination Strategies, Limitations and Future Directions.

Oncolytic viruses (OVs) are characterised by their preference for infecting and replicating in tumour cells either naturally or after genetic modification, resulting in oncolysis. Furthermore, OVs can elicit both local and systemic anticancer immune responses while specifically infecting and lysing tumour cells. These characteristics render them a promising therapeutic approach for paediatric brain tumours (PBTs). PBTs are frequently marked by a cold tumour immune microenvironment (TIME), which suppresses immunotherapies. Recent preclinical and clinical studies have demonstrated the capability of OVs to induce a proinflammatory immune response, thereby modifying the TIME. In-depth insights into the effect of OVs on different cell types in the TIME may therefore provide a compelling basis for using OVs in combination with other immunotherapy modalities. However, certain limitations persist in our understanding of oncolytic viruses' ability to regulate the TIME to enhance anti-tumour activity. These limitations primarily stem from the translational limitations of model systems, the difficulties associated with tracking reliable markers of efficacy throughout the course of treatment and the role of pre-existing viral immunity. In this review, we describe the different alterations observed in the TIME in PBTs due to OV treatment, combination therapies of OVs with different immunotherapies and the hurdles limiting the development of effective OV therapies while suggesting future directions based on existing evidence.

Abstract PO5-15-09: DNA damage induced necroptosis predicts response to radioimmunotherapy

Abstract Background: More than half of all cancer patients receive radiotherapy (RT) during their cancer experience. DNA damage induced by RT can initiate a pro-inflammatory immune response within the tumor microenvironment (TME), yet this response is not uniformly observed across all tumors. Mre11 is one of the first responders to double stranded breaks and coordinates the DNA damage response. Recent work in our lab reveals that Mre11 is required for cGAS mediated detection of cytoplasmic DNA, in turn activating STING to engage the type I interferon signaling pathway, downstream of which can activate ZBP1/RIPK3/MLKL mediated necroptosis. The purpose of this study is to determine if expression of the necroptotic pathway may predict whether breast tumors benefit from RT to overcome ICI resistance and induce systemic anti-tumor immunity in the form of an abscopal response. Methods: Four Trp53-/- Balb/c breast cancer syngeneic allograft models with low tumor mutational burden and resistance to dual ICI (anti-PD1 and anti-CTLA4, BioXcell) were used. Mice were implanted with bilateral tumors and randomly divided into four treatment cohorts: untreated, RT, ICI, or RT+ICI, where RT (8Gyx3) was administered to one tumor. Two lines exhibited abscopal responses to RT+ICI (i.e., “abscopal models”), whereas the other two did not (i.e., “non-abscopal models”). To identify gene expression patterns associated with abscopal responding breast tumors, we performed spatial transcriptomic analysis of tumors 10 days after initiating treatment using the GeoMx whole transcriptome assay targeting panCK+ tumor cells and tumor adjacent CD45+ immune cells (N &amp;gt;5 for each treatment group and tumor type). Unsupervised hierarchical clustering was performed to identify gene expression patterns across areas of interest. Genes selectively induced by RT+ICI in abscopal models that were not induced in non-abscopal models were identified using two-tailed t-test and FDR correction for multiple testing (FDR&amp;lt; 5%). DeSEQ2 and GSEA analysis were performed using publicly available mouse gene sets (Broad Institute). Results: The TME in untreated tumors in the abscopal models demonstrate upregulation in the B cell survival pathway and apoptotic pathways compared to untreated tumors in non-abscopal models. Hierarchical clustering of immune related genes in CD45+ segments of RT+ICI treated tumors exhibiting an abscopal response revealed a global shift in gene expression profiles after treatment. GSEA analysis of CD45+ segments from abscopal models shows that RT+ICI treatment results in enrichment of the interferon mediated signaling pathway including interferon alpha (p&amp;lt; 0.0001), interferon beta (p&amp;lt; 0.0001), type II interferon response (p&amp;lt; 0.0001), and antigen processing and presentation (p&amp;lt; 0.0001). In tumor cells of breast cancers demonstrating the abscopal response, Isg15 and Zbp1 are highly induced by RT+ICI. The necroptotic pathway, including Zbp1, Ripk3, and Mlkl, are significantly higher expressed in the panCK+ tumors known to demonstrate the abscopal response. Conclusion: Breast cancer models with an abscopal response to RT+ICI demonstrate higher expression of Isg15 and Zbp1, both of which are involved in secreted inflammatory signaling. The TME in these models have increased interferon signaling and antigen presentation in response to RT+ICI. The role of DNA damage induced necroptosis in generating an abscopal response in breast cancer warrants further investigation as a potential biomarker for response to RT+ICI combination therapy. Citation Format: Anna Goddard, Qinhong Wang, Minguk Cho, Lynn Lerner, Gaorav Gupta. DNA damage induced necroptosis predicts response to radioimmunotherapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-15-09.

Proteome profile of Leishmania donovani Centrin1−/− parasite-infected human macrophage cell line and its implications in determining possible mechanisms of protective immunity

Our developed cell division-specific ‘centrin’ gene deleted Leishmania donovani (LdCen1−/−) the causative parasite of the fatal visceral-leishmaniasis (VL), exhibits a selective growth arrest at the intracellular stage and is anticipated as a live attenuated vaccine candidate against VL. LdCen1−/− immunization in animals has shown increased IFN-γ secreting CD4+ and CD8+ T cells along with protection conferred by a protective proinflammatory immune response. A label-free proteomics approach has been employed to understand the physiology of infection and predict disease interceptors during Leishmania-host interactions. Proteomic modulation after infection of human macrophage cell lines suggested elevated annexin A6, implying involvement in various biological processes such as membrane repair, transport, actin dynamics, cell proliferation, survival, differentiation, and inflammation, thereby potentiating its immunological protective capacity. Additionally, S100A8 and S100A9 proteins, known for maintaining homeostatic balance in regulating the inflammatory response, have been upregulated after infection. The inhibitory clade of serpins, known to inhibit cysteine proteases (CPs), was upregulated in host cells after 48 h of infection. This is reflected in the diminished expression of CPs in the parasites during infection. Such proteome analysis confirms LdCen1−/− efficacy as a vaccine candidate and predicts potential markers in future vaccine development strategies against infectious diseases.