Acute Immune Response Research Articles

Sequential Ubiquitination and Phosphorylation Epigenetics Reshaping by MG132-Loaded Fe-MOF Disarms Treatment Resistance to Repulse Metastatic Colorectal Cancer.

Abnormal epigenetic regulation is identified to correlate with cancer progression and renders tumor refractory and resistant to reactive oxygen species (ROS)-based anti-tumor actions. To address it, a sequential ubiquitination and phosphorylation epigenetics modulation strategy is developed and exemplified by the well-established Fe-metal-organic framework (Fe-MOF)-based chemodynamic therapy (CDT) nanoplatforms that load the 26S proteasome inhibitor (i.e., MG132). The encapsulated MG132 can blockade 26S proteasome, terminate ubiquitination, and further inhibit transcription factor phosphorylation (e.g., NF-κB p65), which can boost pro-apoptotic or misfolded protein accumulations, disrupt tumor homeostasis, and down-regulate driving genes expression of metastatic colorectal cancer (mCRC). Contributed by them, Fe-MOF-unlocked CDT is magnified to considerably elevate ROS content for repulsing mCRC, especially after combining with macrophage membrane coating-enabled tropism accumulation. Systematic experiments reveal the mechanism and signaling pathway of such a sequential ubiquitination and phosphorylation epigenetics modulation and explain how it could blockade ubiquitination and phosphorylation to liberate the therapy resistance to ROS and activate NF-κB-related acute immune responses. This unprecedented sequential epigenetics modulation lays a solid foundation to magnify oxidative stress and can serve as a general method to enhance other ROS-based anti-tumor methods.

Butyrate regulates neutrophil homeostasis and impairs early antimicrobial activity in the lung

Short-chain fatty acids (SCFAs) are metabolites that are produced after microbial fermentation of dietary fiber and impact cell metabolism and anti-inflammatory pathways both locally in the gut and systemically. In preclinical models, administration of SCFAs, such as butyrate, ameliorates a range of inflammatory disease models including allergic airway inflammation, atopic dermatitis, and influenza infection. Here we report the effect of butyrate on a bacteria-induced acute neutrophil-driven immune response in the airways. Butyrate impacted discrete aspects of hematopoiesis in the bone marrow resulting in the accumulation of immature neutrophils. During Pseudomonas aeruginosa infection, butyrate treatment led to the enhanced mobilization of neutrophils to the lungs as a result of increased CXCL2 expression by lung macrophages. Despite this increase in granulocyte numbers and their enhanced phagocytic capacity, neutrophils failed to control early bacterial growth. Butyrate reduced the expression of nicotinamide adenine dinucleotide phosphate, oxidase complex components required for reactive oxygen species production, and reduced secondary granule enzymes, culminating in impaired bactericidal activity. These data reveal that SCFAs tune neutrophil maturation and effector function in the bone marrow under homeostatic conditions, potentially to mitigate against excessive granulocyte-driven immunopathology, but their consequently restricted bactericidal capacity impairs early control of Pseudomonas infection.

B-arrestin deletion abrogates the innate immune response in murine CVB3 myocarditis

β-arrestins (βarrs), initially discovered as desensitizers of GPCR signaling, are now known to function as intracellular scaffolds and signaling transducers mediating a wide array of signaling cascades including immune responses to inflammatory stimuli. An important cause of immune cell infiltration and cardiac inflammation are viral pathogens such as enterovirus coxsackievirus B3 (CVB3) induced myocarditis. While viral myocarditis is a leading cause of dilated cardiomyopathy, the precise molecular mechanisms for the acute immune response to CVB3 infection are not well understood. Given the important role for βarrs in the acute immune response, we tested the hypothesis that βarrs are necessary for the activation of the acute immune response and mediate the progression and severity of cardiotropic CVB3-induced myocarditis in mice. Five to 7-week-old mice devoid of βarr1 (βarr1 KO) or βarr2 (βarr2 KO) were infected intraperitoneally with 1x103-1x104 plaque forming units (PFU) of CVB3 per animal. Wild type (WT) C57BL/6 mice infected with CVB3 were used as controls. The survival rate 7 days post infection (dpi) was significantly improved in male βarr1 KOs (80%) and βarr2 KOs (75%) compared to male WT control mice (35%, p=0.013). Female WT, βarr1 KO, and βarr2 KO mice showed similar survival rates 7 dpi., ranging from 70% to 80%. Early mortality among all groups before 5 dpi was associated with high viral titers (~6.0 ± 0.5 log10PFU/mg) in the liver compared to mortality after 5 dpi (~2.4 ± 1.7 log10PFU/mg) as determined by plaque assay. Viral titers in the heart (WT=3.7 ± 0.9 log10PFU/mg, βarr1KO=3.6 ± 1.3 log10PFU/mg, βarr2KO=3.5 ± 1.2log10PFU/mg) were similar among all groups suggesting that βarrs are not involved in viral replication. Morphometric analysis showed similar weight loss (~18%) across all groups at 7 dpi corroborated by viral cardiac PFU. Immunofluorescent staining of the heart with the pan-inflammatory marker, CD45, revealed high immune cell infiltration in infected WT mice (34.2% ± 4.5%), whereas immune cell infiltration was significantly blunted in infected βarr1 KO (6.0% ± 1.1%; p<0.0001) and βarr2 KO (8.5% ± 0.9%; p<0.0001) mice. The degree of immune cell infiltration in hearts of infected WT mice was directly correlated with an increase in heart viral titer, whereas immune cell infiltration remained blunted across a broad range of heart viral titers in both βarr1 and 2 KO mice. The blunted immune response in both βarr KOs compared to WT infected controls was consistent across multiple immune cell markers including CD4 for helper T cells and CD11b for innate immune cells. In conclusion, we demonstrate that βarrs are necessary for immune cell recruitment to the heart in CVB3 myocarditis and deletion of βarrs in male mice may be cardioprotective as indicated by an increase in survival rate. These data suggest that βarrs may serve as potential therapeutic targets in the treatment of acute viral myocarditis. This work was supported by the National Institutes of Health Grants HL056687 (to H.A.R.). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

VEGFR-3 Stimulation on LECs Boosts Type 2 Immunity After Vaccination

Abstract Lymphatic vessels are the main transport routes for fluid, antigens, exosomes, and immune cells from peripheral tissues to the lymph nodes (LNs). In addition to being pervasive through tissue, lymphatic vessels are also abundant within the LN, where they route lymph and cells around the B cell follicles and throughout the paracortical zone; thus, lymphatic endothelial cells (LECs) have unique access to lymph-borne molecules and interactions with immune cells. Upon acute inflammation or vaccination, LN LECs undergo expansion along with lymphocyte proliferation, a process dependent on the VEGF-C/VEGFR-3 signaling axis; however, it is not well understood how LN lymphatics and their expansion contribute to acute adaptive immune responses. Here, we asked how altering VEGFR-3 signaling LN LECs alters the adaptive immune response, using OVA + CpG (a TLR9 agonist) as a model for vaccination. We found that delivering VEGF-C156S, a VEGFR-3 specific agonist, multiple times prior to and concurrent with the inflammatory stimulus led to increased Th2 responses in terms of higher plasma levels of OVA-specific IgG1, more IgG1+ germinal center B cells, and increased production of Th2 cytokines (IL-4, IL-5, and IL-13) by CD4+ T cells upon restimulation. In loss-of-function experiments using a tamoxifen-inducible LEC-specific deletion of VEGFR-3, vaccination led to reduced plasma levels of OVA-specific IgG1 compared to tamoxifen-treated control littermates. Together, these findings suggest that in response to vaccination, VEGFR-3 signaling in LN LECs bias adaptive immune responses towards type 2 immunity. This highlights the role of lymphatics not just as passive conduits for fluid transport, but as having direct immunomodulatory function.

ANKLE LIGAMENT REPAIR FOR RESTORATION OF FUNCTION: EXPLORING THE APPLICATION OF DECELLULARIZED GRAFTS

Ligament integrity is directly associated with ankle stability. Nearly 40% of ankle sprains result in chronic ankle instability, affecting biomechanics and potentially causing osteoarthritis. Ligament replacement could restore stability and avoid this degenerative pathway, but a greater understanding of ankle ligament behaviour is required. Additionally, autograft or allograft use is limited by donor-site morbidity and inflammatory responses respectively. Decellularised porcine grafts could address this, by removing cellular material to prevent acute immune responses, while preserving mechanical properties.This project will characterise commonly injured ankle ligaments and damage mechanisms, identify ligament reconstruction requirements, and investigate the potential of decellularised porcine grafts as a replacement material.Several porcine tendons were evaluated to identify suitable candidates for decellularisation. The viscoelastic properties of native tissues were assessed using dynamic mechanical analysis (DMA), followed by ramp to ‘sub-rupture’ at 1% strain/s, and further DMA. Multiple samples (n=5) were taken along the graft to assess variation along the tendon.When identifying suitable porcine tendons, a lack of literature on human ankle ligaments was identified. Inconsistencies in measurement methods and properties reported makes comparison between studies difficult.Preliminary testing on porcine tendons suggested there is little variation in viscoelastic properties along the length of tendon. Testing also suggested strain rates of 1%/s sub-rupture was not large enough to affect viscoelastic properties (no changes in storage or loss moduli or tanẟ). Further testing is underway to improve upon low initial sample numbers and confirm these results, with varying strain rates to identify suitable sub-rupture sprain conditions.This work highlights need for new data on human ankle ligaments to address knowledge gaps and identify suitable replacement materials. Future work will generate this data and decellularise porcine tendons of similar dimensions. Collagen damage will be investigated using histology and lightsheet microscopy, and viscoelastic changes through DMA.

Abstract 4585: Tumor lymphangiogenesis sensitizes melanomas to the immunological effects of radiotherapy but also disrupts the local lymphatic vasculature

Abstract Tumor lymphangiogenesis is typically associated with cancer progression and metastasis. However, recent studies from our group have demonstrated that tumor lymphangiogenesis promotes intratumor T cell infiltration and potentiates the efficacy of a wide range of immunotherapies in melanoma-bearing mice as well as patients undergoing checkpoint blockade. Radiotherapy (RT) can also induce immunogenic tumor cell death, so we investigated whether lymphangiogenic tumors would yield more immunogenic responses to RT than non-lymphangiogenic tumors. Here, we compared effects of RT in mice bearing B16-F10 melanomas expressing either a control vector (B16-Ctrl) or overexpression the lymphangiogenic factor VEGF-C (B16-VC), where lymphatic vessels were significantly increased in number and size compared to B16-Ctrl tumors. First, we find that B16-VC regress faster than B16-CT after RT (either a single 20 Gy dose or two 15 Gy doses), and that this regression was correlated with enhanced CD8+ T cell activity. On the other hand, lymphatic endothelial cells (LECs) can be more sensitive to damage from RT if they are undergoing lymphangiogenesis. We found that irradiated B16-VC tumors showed higher levels of intra-lymphatic fibrin. Consistent with this, LECs in the irradiated B16-VC tumors expressed higher levels of tissue factor and caspase-3, which correlated with the degree of lymphatic clotting. Fibrin clotting was also observed in the subcapsular sinus of the draining lymph nodes of irradiated B16-VC tumors. These findings highlight the complex role of tumor lymphangiogenesis in radiotherapy responses, where they may potentiate acute anti-tumor immune responses but may also cause localized damage of the vasculature, potentially leading to increased metastasis. Further studies are needed to investigate therapeutic targets to inhibit lymphatic coagulation and look at its effects on cancer immunotherapy and metastasis. Citation Format: Anish Mukherjee, Nikolaos Mitrousis, Mari Stella Sasso, Margo MacDonald, Ainhoa Arina, Phillip Ang, Ariana Baginski, J. Emiliano G. Medellin, Ralph R. Weichselbaum, Melody A. Swartz. Tumor lymphangiogenesis sensitizes melanomas to the immunological effects of radiotherapy but also disrupts the local lymphatic vasculature. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4585.

464 Chronic HIV infection influences the immune response during acute COVID-19 and long COVID

OBJECTIVES/GOALS: Despite highly effective antiretroviral therapy, people living with HIV (PLWH) experience chronic immune activation and inflammation which may influence the progression of infections such as SARS-CoV-2. Here, we explore the immune response and clinical outcomes in HIV(+) and HIV(-) individuals experiencing acute COVID-19 and long COVID (LC). METHODS/STUDY POPULATION: We performed flow cytometric analyses on peripheral blood mononuclear cells from the following: 1) HIV(-) individuals experiencing acute COVID-19, 2) PLWH experiencing acute COVID-19, and 3) pre-COVID-19 pandemic PLWH. Additionally, we will perform similar analyses for the following: 1) PLWH experiencing LC, 2) PLWH previously infected with SARS-CoV-2 who recovered, 3) pre-COVID-19 pandemic PLWH, and 4) HIV(-) individuals experiencing LC. Flow cytometry panels include surface markers for immune cell populations, activation and exhaustion surface markers (with and without SARS-CoV-2-specific antigen stimulation), and intracellular cytokine staining. We will also analyze how chronic HIV infection and other clinical and demographic factors (e.g., age, CD4 %) impact persistent symptomatic burden. RESULTS/ANTICIPATED RESULTS: Acute COVID-19 results–Overall, PLWH had higher baseline expression of activation markers OX40 and CD137 on CD4+ and CD8+ T cells, along with increased levels of TNFa producing CD8+ T cells. Interestingly, PLWH had increased expression of exhaustion markers PD1 and TIGIT but decreased expression of TIM3 on CD4+ and CD8+ T cells. Additionally, PLWH had decreased levels of IL-2 and IFNg producing CD4+ T cells which suggests functional exhaustion. Long COVID-19 expected results–we hypothesize that the activation and inflammation seen in chronic HIV infection will lead to more immune dysregulation and subsequently worsened symptomatic burden. Additionally, we hypothesize that PLWH may have different frequencies of certain LC manifestations, such as increased rates of neurocognitive impairment. DISCUSSION/SIGNIFICANCE: Our findings suggest that chronic HIV infection influences acute immune response during SARS-CoV-2 infection, and that PLWH have variable expression of exhaustion markers which warrants further study. Additionally, our findings in the LC cohort will aid in characterizing clinical manifestations and immunologic mechanisms of LC in PLWH.

Acute oral toxicity, apoptosis, and immune response in nurse bees (Apis mellifera) induced by flupyradifurone.

The potential toxicity of flupyradifurone (FPF) to honey bees has been a subject of controversy in recent years. Understanding the effect of pesticides on nurse bees is important because the fitness of nurse bees is critical for in-hive activities, such as larval survival and performing hive maintenance. In order to evaluate the acute oral toxicity of flupyradifurone on nurse bees, flupyradifurone at five different concentrations was selected to feed both larvae and nurse bees. Our results showed that nurse bees were more sensitive to flupyradifurone than larvae (LD50 of the acute oral toxicity of flupyradifurone was 17.72μg a.i./larva and 3.368μg a.i./nurse bee). In addition, the apoptotic rates of neurons in mushroom bodies of nurse bees were significantly induced by flupyradifurone at sublethal concentrations (8mg/L, 20mg/L, and 50mg/L) and the median lethal concentration LC50 (125mg/L). The expression of immune-related genes (Hsp90, Toll-8/Tollo, and defensin) was significantly changed in exposed nurse bees at the field-realistic concentration of flupyradifurone. However, three detoxifying enzyme genes (CYP9Q1, -2, and -3) were not affected by pesticide exposure. Our data suggest that although flupyradifurone had a relatively lower acute oral toxicity than many other common pesticides, exposures to the field-realistic and other sublethal concentrations of flupyradifurone still have cytotoxicity and immune-responsive effects on nurse bees. Therefore, flupyradifurone should be considered for its application in crops.

Immune Cells in Cardiac Injury Repair and Remodeling.

Immune cells are emerging as central cellular components of the heart which communicate with cardiac resident cells during homeostasis, cardiac injury, and remodeling. These findings are contributing to the development and continuous expansion of the new field of cardio-immunology. We review the most recent literature on this topic and discuss ongoing and future efforts to advance this field forward. Cell-fate mapping, strategy depleting, and reconstituting immune cells in pre-clinical models of cardiac disease, combined with the investigation of the human heart at the single cell level, are contributing immensely to our understanding of the complex intercellular communication between immune and non-immune cells in the heart. While the acute immune response is necessary to initiate inflammation and tissue repair post injury, it becomes detrimental when sustained over time and contributes to adverse cardiac remodeling and pathology. Understanding the specific functions of immune cells in the context of the cardiac environment will provide new opportunities for immunomodulation to induce or tune down inflammation as needed in heart disease.

The first description of the blue swimming crab (Portunus pelagicus) transcriptome and immunological defense mechanism in response to white spot syndrome virus (WSSV)

In the global shellfish farming industry, white spot syndrome virus (WSSV) is a major cause of mortality and a significant factor in economic losses. However, information on molecular immune responses to WSSV in blue swimming crabs (Portunus pelagicus) has never been reported. First, viral loads were measured in the gills, hepatopancreas, intestines, subcuticular epithelium and hemocytes of blue swimming crabs (50 ± 10 g) (n = 4) after WSSV induction at 0, 24, 48 and 96 h post injection (hpi). A significant increase in WSSV particles was observed in gills at 48 and 96 hpi, as supported by histopathology. To further investigate the acute immune response to WSSV, total RNA from the same gill tissues at 0, 24, and 96 hpi was used to construct 16 high-quality RNA-seq cDNA libraries. In summary, 162,740 unigenes were discovered in these transcriptomic libraries analyzed with the GO, KO, KOG, NR, NT, PFAM and SwissProt databases. Intensive sequence analysis against control crabs using three major categories of gene oncology (GO) of DEGs, biological processes (BPs), molecular functions (MFs), and cellular components (CCs), indicated that induction of WSSV in blue swimming crabs strongly affected the immune responses of the target animals significantly during the early stages of infection from 24 to 96 hpi. Furthermore, KEGG identified approximately twenty biological pathways of gene expression that were both downregulated and upregulated. Interestingly, at 24 and 96 hpi, several immune-related genes involved in virus defense in the blue swimming crab, particularly crustin 2, chitinase, anti-lipopolysaccharide, proteinase inhibitor, and lysozyme, were highly expressed during the WSSV early infection stages. At the same time, viral mRNA transcripts, including WSV289, WSV343, WSV306, deoxyuridine 5’ triphosphate nucleohydrolase, RING finger containing E3 ubiquitin-protein ligase WSV403 and WSV404, were recorded in the top twenty upregulated genes. Moreover, some immune-responsive genes related to growth development, such as chitinase, tubulin alpha and beta chains, trypsin, and the cathepsin family, were also differentially expressed during these periods. Expression validation of 20 upregulated and 11 downregulated immune-related genes using qRT‒PCR showed similar patterns with transcriptome information. Overall, the data showed that during WSSV infection, a number of immune-, metabolism-, and growth-related pathways were activated, and several of the pathways involved differed depending on the stage of virus invasion. These findings could effectively help us better understand the impact of WSSV on the physiology of blue swimming crabs and serve as a valuable reference for future research on the immune system and disease control in this target species.

How COVID-19 and other pathological conditions and medical treatments activate our intravascular innate immune system.

COVID-19 has been shown to have a multifaceted impact on the immune system. In a recently published article in Front Immunol, we show that the intravascular innate immune system (IIIS) is strongly activated in severe COVID-19 with ARDS and appears to be one of the causes leading to severe COVID-19. In this article, we describe the IIIS and its physiological function, but also the strong pro-inflammatory effects that are observed in COVID-19 and in various other pathological conditions and treatments such as during ischemia reperfusion injury and in treatments where biomaterials come in direct contact with blood in, e.g., extracorporeal and intravasal treatments. In the present article, we describe how the IIIS, a complex network of plasma proteins and blood cells, constitute the acute innate immune response of the blood and discuss the effects that the IIIS induces in pathological disorders and treatments in modern medicine.

Acute and long-term immune responses to SARS-CoV-2 infection in unvaccinated children and young adults with inborn errors of immunity.

To describe SARS-CoV-2 infection outcome in unvaccinated children and young adults with inborn errors of immunity (IEI) and to compare their specific acute and long-term immune responses with a sex-, age-, and severity-matched healthy population (HC). Unvaccinated IEI patients up to 22 years old infected with SARS-CoV-2 were recruited along with a cohort of HC. SARS-CoV-2 serology and ELISpot were performed in the acute phase of infection (up to 6 weeks) and at 3, 6, 9, and 12 months. Twenty-five IEI patients (median age 14.3 years, min.-max. range 4.5-22.8; 15/25 males; syndromic combined immunodeficiencies: 48.0%, antibody deficiencies: 16.0%) and 17 HC (median age 15.3 years, min.-max. range 5.4-20.0; 6/17 males, 35.3%) were included. Pneumonia occurred in 4/25 IEI patients. In the acute phase SARS-CoV-2 specific immunoglobulins were positive in all HC but in only half of IEI in whom it could be measured (n=17/25): IgG+ 58.8% (10/17) (p=0.009); IgM+ 41.2% (7/17)(p<0.001); IgA+ 52.9% (9/17)(p=0.003). Quantitative response (index) was also lower compared with HC: IgG IEI (3.1 ± 4.4) vs. HC (3.5 ± 1.5)(p=0.06); IgM IEI (1.9 ± 2.4) vs. HC (3.9 ± 2.4)(p=0.007); IgA IEI (3.3 ± 4.7) vs. HC (4.6 ± 2.5)(p=0.04). ELISpots positivity was qualitatively lower in IEI vs. HC (S-ELISpot IEI: 3/11, 27.3% vs. HC: 10/11, 90.9%; p=0.008; N-ELISpot IEI: 3/9, 33.3% vs. HC: 11/11, 100%; p=0.002) and also quantitatively lower (S-ELISpot IEI: mean index 3.2 ± 5.0 vs. HC 21.2 ± 17.0; p=0.001; N-ELISpot IEI: mean index 9.3 ± 16.6 vs. HC: 39.1 ± 23.7; p=0.004). As for long term response, SARS-CoV-2-IgM+ at 6 months was qualitatively lower in IEI(3/8, 37.5% vs. 9/10 HC: 90.0%; p=0.043), and quantitatively lower in all serologies IgG, M, and A (IEI n=9, 1.1 ± 0.9 vs. HC n=10, 2.1 ± 0.9, p=0.03; IEI n=9, 1.3 ± 1.5 vs. HC n=10, 2.9 ± 2.8, p=0.02; and IEI n=9, 0.6 ± 0.5 vs. HC n=10, 1.7 ± 0.8, p=0.002 -respectively) but there were no differences at remaining time points. Our IEI pediatric cohort had a higher COVID-19 pneumonia rate than the general age-range population, with lower humoral and cellular responses in the acute phase (even lower compared to the reported IEI serological response after SARS-CoV-2 vaccination), and weaker humoral responses at 6 months after infection compared with HC.

Effect of oestrus synchronisation through ovulation delay by vaccination against foot-and-mouth disease in Hanwoo (Bos taurus coreanae) cows.

In Korean cattle, after foot-and-mouth disease (FMD) vaccination, anovulation increases, acute immune response is stimulated. Here, we aimed to improve the fertility rate by ovulation delay caused by the foot-and-mouth disease vaccine. 160 cows (control, FMD, FMD+Gn250 and FMD+Gn500 groups, with 40 cows each) were used. We analysed the ovulation delay, ovulation rate, conception rate and acute-phase immune responses. In the group vaccinated only with FMD, the average follicle size was maintained at 12mm and ovulation was delayed. The ovulation rate of the FMD+Gn500 group (500μg gonadotropin-releasing hormone (GnRH) injections 3 days after the FMD vaccination) was the highest at 81.8%. The ovulation rate of the FMD+Gn250 group (250μg GnRH injections 3 days after FMD vaccination) was 54.5%, and that of the control group (not FMD vaccinated) was 53.3%. The conception rate was 52.5% (19/40) in the control group, 37.5% (15/40) in the FMD+Gn250 group, and 67.5% (27/40) in the FMD+Gn500 group. Analysis of acute-phase immune response revealed that the plasma contents of haptoglobin and serum amyloid A increased up to 7 days after vaccination against FMD in all the experimental groups, except the control group. We concluded that ovulation delay can be employed to improve conception rate after FMD vaccination through a modified ovulation synchronisation method with GnRH.

Treating SARS-CoV-2 Based Upon the Fleming InflammoThrombotic Response (ITR) &amp; Cardiovascular Disease Theory

This paper discusses the importance of addressing, measuring and treating the infectious, inflammatory and thrombotic tissue effect resulting from the body’s immunologic response to SARS-CoV-2 using methods previously detailed in the medical literature, in an effort to reduce SARS-CoV-2 morbidity and mortality. Successful treatment of SARS-CoV-2 requires addressing each of the four stages of the viral infection including oxygenation, acute cytotoxic immune response, adaptive humoral-antibody response, and viral cellular attachment and replication. Information obtained from the National Clinical Trial NCT04349410 has proven the benefit of treating each of these four factors. A paper detailing the NCT04349410 results has been published elsewhere.

α-Tocopherol Transfer Protein-Null Mice with Very Low α-Tocopherol Status Do Not Have an Enhanced Lipopolysaccharide-Induced Acute Inflammatory Response

BackgroundThe α-tocopherol transfer protein-null (Ttpa−/−) mouse model is a valuable tool for studying the molecular and functional consequences of vitamin E (α-tocopherol, αT) deficiency. Because αT has been associated with reduced oxidative stress and improved immune function, we hypothesized that depleted αT concentration would exacerbate LPS-induced acute inflammatory response in the brain and heart of Ttpa−/− mice fed a vitamin E deficient (VED) diet. ObjectivesThe objective was to investigate how extremely low αT status, followed by exposure to LPS, altered the acute inflammatory response to LPS in Ttpa−/− and wild-type (Ttpa+/+) mice. MethodsThree-week-old male Ttpa+/+ and Ttpa−/− littermates (n = 36/genotype) ingested a VED diet ad libitum for 4 wk. At week 7, mice received an intraperitoneal LPS (1 or 10 μg/mouse) or saline (control) injection and were killed 4 h postinjection. Brain and heart IL-6 protein concentrations and tissue and serum αT concentrations were measured via ELISA and HPLC with photodiode array detection, respectively. Hippocampal Il-6, Tnf, and Gpx1 gene expression were measured via reverse transcriptase-quantitative polymerase chain reaction, and blood immune cell profiles were measured via a hematology analyzer. ResultsαT accumulation in analyzed tissues and serum of Ttpa−/− mice was substantially lower than Ttpa+/+ mice. Circulating white blood cell concentration, particularly lymphocytes, were lower in all LPS groups compared with controls (P < 0.01). The 10 μg LPS groups had elevated IL-6 in the cerebellum and heart compared with controls, confirming an acute inflammatory response (P < 0.01). Hippocampal and heart Il-6 gene expression in the LPS-treated Ttpa−/− mice was upregulated in a dose-dependent manner (P < 0.05). ConclusionsThe 10 μg LPS dose enhanced inflammatory markers in the brain, heart, and serum in each genotype but the lower αT status in Ttpa−/− mice did not further impact the acute immune responses.

An understanding of the immune dysfunction in susceptible people who develop the post-viral fatigue syndromes Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long COVID

Viral infection in most people results in a transient immune/inflammatory response resulting in elimination of the virus and recovery where the immune system returns to that of the pre-infectious state. In susceptible people by contrast there is a transition from an acute immune response to a chronic state that can lead to an ongoing lifelong complex post-viral illness, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. This susceptibility is proposed to be genetic or be primed by prior health history. Complex abnormalities occur in immune cell functions, immune cell metabolism and energy production, and in cytokine immune modulator regulation. The immune system of the brain/central nervous system becomes activated leading to dysfunction in regulation of body physiology and the onset of many neurological symptoms. A dysfunctional immune system is core to the development of the post-viral condition as shown with diverse strategies of immune profiling. Many studies have shown changes in numbers and activity of immune cells of different phenotypes and their metabolism. Immune regulating cytokines show complex altered patterns and vary with the stage of the disease, and there are elements of associated autoimmunity. These complex changes are accompanied by an altered molecular homeostasis with immune cell transcripts and proteins no longer produced in a tightly regulated manner, reflected in the instability of the epigenetic code that controls gene expression. Potential key elements of the altered immune function in this disease needing further exploration are changes to the gut-brain-immune axis as a result of changes in the microbiome of the gut, and viral reactivation from latent elements of the triggering virus or from a prior viral infection. Long COVID, an Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-like illness, is the post-viral condition that has arisen in large numbers solely from the pandemic virus Severe Acute Respiratory Syndrome Coronovirus-2. With over 760 million cases worldwide, an estimated ~100 million cases of Long COVID have occurred within a short period. This now provides an unprecedented opportunity to understand the progression of these post-viral diseases, and to progress from a research phase mainly documenting the immune changes to considering potential immunotherapies that might improve the overall symptom profile of affected patients, and provide them with a better quality of life.

A simple liposome-based bionic bacterium for tumor treatment by re-education of tumor-associated microphages in combination with chemotherapy

Re-education of tumor-associated macrophages (TAMs) into M1-like macrophages (Mφ1) has become one of the aims of tumor immunotherapy. Injection of live bacteria has been applied for this purpose; however, an acute innate immune response might be caused in this progress, and therefore a bacteria-based strategy with great security is needed. In this study, the bacterial walls of Staphylococcus aureus were inserted into the bilayer of liposome to construct liposome-based bionic bacteria (Bio-Bac), and doxorubicin (DOX) was encapsulated to form DOX@Bio-Bac. DOX@Bio-Bac re-educated the THP-1-derived TAMs into Mφ1 in vitro, and subsequently inhibited the migration and invasion of CAL27 cells. In a mouse model of hepatocellular carcinoma with lymphatic metastasis, the re-education of TAMs was proved, and an effective inhibition of tumor growth and metastasis in mice was observed. The liposome-based bionic bacteria constructed in this study provide a new strategy for re-education of TAMs, replacing the bacterial therapy reported previously, and a more effective anti-tumor effect can be obtained by combining the chemotherapy drugs with this bionic bacterium.

Proteomic profiling of end-stage COVID-19 lung biopsies

The outbreak of a novel coronavirus (SARS-CoV-2) in 2019 led to a worldwide pandemic, which remains an integral part of our lives to this day. Coronavirus disease (COVID-19) is a flu like condition, often accompanied by high fever and respiratory distress. In some cases, conjointly with other co-morbidities, COVID-19 can become severe, leading to lung arrest and even death. Although well-known from a clinical standpoint, the mechanistic understanding of lethal COVID-19 is still rudimentary. Studying the pathology and changes on a molecular level associated with the resulting COVID-19 disease is impeded by the highly infectious nature of the virus and the concomitant sampling challenges. We were able to procure COVID-19 post-mortem lung tissue specimens by our collaboration with the BSL-3 laboratory of the Biobanking and BioMolecular resources Research Infrastructure Austria which we subjected to state-of-the-art quantitative proteomic analysis to better understand the pulmonary manifestations of lethal COVID-19. Lung tissue samples from age-matched non-COVID-19 patients who died within the same period were used as controls. Samples were subjected to parallel accumulation–serial fragmentation combined with data-independent acquisition (diaPASEF) on a timsTOF Pro and obtained raw data was processed using DIA-NN software. Here we report that terminal COVID-19 patients display an increase in inflammation, acute immune response and blood clot formation (with concomitant triggering of fibrinolysis). Furthermore, we describe that COVID-19 diseased lungs undergo severe extracellular matrix restructuring, which was corroborated on the histopathological level. However, although undergoing an injury, diseased lungs seem to have impaired proliferative and tissue repair signalling, with several key kinase-mediated signalling pathways being less active. This might provide a mechanistic link to post-acute sequelae of COVID-19 (PASC; “Long COVID”). Overall, we emphasize the importance of histopathological patient stratification when interpreting molecular COVID-19 data.

Plasma proteins from several components of the immune system differentiate chronic widespread pain patients from healthy controls - an exploratory case-control study combining targeted and non-targeted protein identification.

Chronic widespread pain (CWP), including fibromyalgia (FM), is characterized by generalized musculoskeletal pain and hyperalgesia. Plasma proteins from proteomics (non-targeted) and from targeted inflammatory panels (cytokines/chemokines) differentiate CWP/FM from controls. The importance of proteins obtained from these two sources, the protein-protein association network, and the biological processes involved were investigated. Plasma proteins from women with CWP (n = 15) and CON (n = 23) were analyzed using two-dimensional gel electrophoresis analysis and a multiplex proximity extension assay for analysis of cytokines/chemokines. Associations between the proteins and group were multivarietly analyzed. The protein-protein association network and the biological processes according to the Gene Ontology were investigated. Proteins from both sources were important for group differentiation; the majority from the two-dimensional gel electrophoresis analysis. 58 proteins significantly differentiated the two groups (R2 = 0.83). A significantly enriched network was found; biological processes were acute phase response, complement activation, and innate immune response. As with other studies, this study shows that plasma proteins can differentiate CWP from healthy subjects. Focusing on cytokines/chemokines is not sufficient to grasp the peripheral biological processes that maintain CWP/FM since our results show that other components of the immune and inflammation systems are also highly significant.

Abstract 15471: Neonatal Mesenchymal Stem Cells Rejuvenate Cardiac Myocardium by Regulating Macrophage Polarization Revealed by Single Cell Sequencing After Ischemia-Reperfusion Injury in Rats

Introduction: Stem cells are an emerging therapy for cardiovascular disease. The immune system is modulated by stem cell administration, therefore we sought to characterize the immune environment following stem cell administration. Hypothesis: Neonatal cardiac mesenchymal stem cells (nMSC) improved heart function through an acute sterile immune response characterized by the temporal and regional of macrophages. Methods: nMSC were isolated from healthy neonatal myocardium. Brown Norway rats underwent ischemia-reperfusion injury (IRI) by temporary ligation of left anterior descending artery for 45 minutes. Following closure of the chest cavity, neonatal mesenchymal stem cells (nMSCs), dead nMSCs (dnMSCs), or placebo was administered by intra-coronary injection. At day five heart was collected for single cell suspensions. CD45 positive selection was performed and fed into the Chromium Single Cell Gene Expression workflow (Pleasanton, CA). Single cell sequencing analysis was completed using the Seurat package on RStudio v1.3.1093 (Boston, MA). Echocardiography was completed on post-operative days 7 and 28 for rats not sacrificed for single cell sequencing. Results: Our results demonstrate that nMSC treatment after IRI injury can significantly recover left ventricular ejection fraction. Single-cell sequencing analysis of CD45+ cells identified multiple unique CD68+ clusters. Notably, macrophage cluster 2 primarily consisted of cells from the nMSC treated group, whereas the macrophage cluster 1 was primarily cells from the dnMSC and placebo groups. Gene ontology analysis of macrophage cluster 2 demonstrated that this cluster primarily consisted of macrophages strongly associated with various aspects of the activated immune response, including lymphocyte activation and cytokine production. Conversely, macrophage cluster 1 gene ontology analysis revealed a weaker immune response signature. Conclusions: nMSCs are a promising therapeutic candidate for the treatment of myocardial infarction. The mechanism of this therapy is likely related to macrophage activation that further enhances the immune response in the impacted and at-risk myocardium following IRI injury.