Cardiolipin-mediated PPARγ S112 phosphorylation impairs IL-10 production and inflammation resolution during bacterial pneumonia.

Bacterial pneumonia is a global healthcare burden, and unwarranted inflammation is suggested as an important cause of mortality. Optimum levels of the anti-inflammatory cytokine IL-10 are essential to reduce inflammation and improve survival in pneumonia. Elevated levels of the mitochondrial-DAMP cardiolipin (CL), reported in tracheal aspirates of pneumonia patients, have been shown to block IL-10 production from lung MDSCs. Although CL-mediated K107 SUMOylation of PPARγ has been suggested to impair this IL-10 production, the mechanism remains elusive. We identify PIAS2 to be the specific E3-SUMOligase responsible for this SUMOylation. Moreover, we identify a concomitant CL-mediated PPARγ S112 phosphorylation, mediated by JNK-MAPK, to be essential for PIAS2 recruitment. Furthermore, using a clinically tested peptide inhibitor targeting JNK-MAPK, we blocked these post-translational modifications (PTMs) of PPARγ and rescued IL-10 expression, improving survival in murine pneumonia models. Thus, we explore the mechanism of mito-DAMP-mediated impaired lung inflammation resolution and propose a therapeutic strategy targeting PPARγ PTMs.

Dynamic Cardiolipin Synthesis Is Required for CD8+ T Cell Immunity.

Mitochondria constantly adapt to the metabolic needs of a cell. This mitochondrial plasticity is critical to T cells, which modulate metabolism depending on antigen-driven signals and environment. We show here that de novo synthesis of the mitochondrial membrane-specific lipid cardiolipin maintains CD8+ T cell function. T cells deficient for the cardiolipin-synthesizing enzyme PTPMT1 had reduced cardiolipin and responded poorly to antigen because basal cardiolipin levels were required for activation. However, neither de novo cardiolipin synthesis, nor its Tafazzin-dependent remodeling, was needed for T cell activation. In contrast, PTPMT1-dependent cardiolipin synthesis was vital when mitochondrial fitness was required, most notably during memory T cell differentiation or nutrient stress. We also found CD8+ T cell defects in a small cohort of patients with Barth syndrome, where TAFAZZIN is mutated, and in a Tafazzin-deficient mouse model. Thus, the dynamic regulation of a single mitochondrial lipid is crucial for CD8+ T cell immunity.

A 31-Year-Old Man with COVID-19-Associated Empyema and Lupus Anticoagulant.

BACKGROUND COVID-19 was declared a pandemic in March 2020 in the United States. It has been associated with high mortality and morbidity all over the world. COVID-19 can cause a significant inflammatory response leading to coagulopathy and this hypercoagulable state has been associated with worse clinical outcomes in these patients. The published data regarding the presence of lupus anticoagulant in critically ill COVID-19-positive patients is limited and indicates varying conclusions so far. CASE REPORT Here, we present a case of a 31-year-old man who was admitted to the hospital with COVID-19 pneumonia, complicated with superadded bacterial empyema and required video-assisted thoracoscopic surgery with decortication. This patient also had prolonged prothrombin time on preoperative labs, which was not corrected with mixing study. Further workup detected positive lupus anticoagulant and anti-cardiolipin IgM along with alteration in other coagulation factor levels. The patient was treated with fresh frozen plasma and vitamin K before surgical intervention. He had an uneventful surgical course. He received prophylactic-dose low molecular weight heparin for venous thromboembolism prophylaxis and did not experience any thrombotic events while hospitalized. CONCLUSIONS COVID-19 infection creates a prothrombotic state in affected patients. The formation of micro-thrombotic emboli results in significantly increased mortality and morbidity. Routine anticoagulation with low molecular weight heparin can prevent thrombotic events and thus can improve patient outcomes. In patients with elevated prothrombin time, lupus anticoagulant/anti-cardiolipin antibody-positivity should be suspected, and anticoagulation prophylaxis should be continued perioperatively for better outcomes.

Stiff person syndrome with elevated titers of antibodies against cardiolipin and ß2 glycoprotein 1: a case report and literature review.

We reported a Stiff person syndrome (SPS) patient with elevated autoantibodies against cardiolipin and ß2 glycoprotein 1 but without glutamic acid decarboxylase (GAD) antibodies. A 40-year male was admitted due to limited mouth opening for 1 week. His blood routine, biochemical, infectious diseases, tumor markers, radiographic examinations were all normal. At day 3 (D3) after admission, he developed paroxysmal systemic muscle rigidity. At D6, the on-duty physician occasionally gave oral clonazepam, which effectively relieved the symptom. At D13, the titers of cardiolipin and ß2 glycoprotein 1 autoantibodies elevated but the remaining autoantibodies were all in normal ranges. After clonazepam treatment for 1 week, the symptoms were basically relieved, and the titers of these two antibodies returned to normal range with the relief of symptoms. During the 3 years of follow-up, the symptoms did not present again, and the titers of both antibodies were stable in the normal ranges. He had no tumor and other immune system diseases. In summary, we reported a SPS case with elevated cardiolipin and ß2 glycoprotein 1 autoantibodies. The patient was highly responsive to clonazepam therapy, and had favorable outcome in the 3 years follow-up. Our report is helpful for better understand the heterogeneous feature of SPS.

Cardiolipin activates antigen-presenting cells via TLR2-PI3K-PKN1-AKT/p38-NF-kB signaling to prime antigen-specific naïve T cells in mice.

Mitochondrial defects and antimitochondrial cardiolipin (CL) antibodies are frequently detected in autoimmune disease patients. CL from dysregulated mitochondria activates various pattern recognition receptors, such as NLRP3. However, the mechanism by which mitochondrial CL activates APCs as a damage-associated molecular pattern to prime antigen-specific naïve T cells, which is crucial for T-cell-dependent anticardiolipin IgG antibody production in autoimmune diseases is unelucidated. Here, we show that CL increases the expression of costimulatory molecules in CD11c+ APCs both in vitro and in vivo. CL activates CD11c+ APCs via TLR2-PI3K-PKN1-AKT/p38MAPK-NF-κB signaling. CD11c+ APCs that have been activated by CL are sufficient to prime H-Y peptide-specific naïve CD4+ T cells and OVA-specific naïve CD8+ T cells. TLR2 is necessary for anti-CL IgG antibody responses in vivo. Intraperitoneal injection of CL does not activate CD11c+ APCs in CD14 KO mice to the same extent as in wild-type mice. CL binds to CD14 (Kd = 7 × 10-7 M). CD14, but not MD2, plays a role in NF-kB activation by CL, suggesting that CD14+ macrophages contribute to recognizing CL. In summary, CL activates signaling pathways in CD11c+ APCs through a mechanism similar to gram (+) bacteria and plays a crucial role in priming antigen-specific naïve T cells.

Dichotomous roles for externalized cardiolipin in extracellular signaling: Promotion of phagocytosis and attenuation of innate immunity.

Among the distinct molecular signatures present in the mitochondrion is the tetra-acylated anionic phospholipid cardiolipin, a lipid also present in primordial, single-cell bacterial ancestors of mitochondria and multiple bacterial species today. Cardiolipin is normally localized to the inner mitochondrial membrane; however, when cardiolipin becomes externalized to the surface of dysregulated mitochondria, it promotes inflammasome activation and stimulates the elimination of damaged or nonfunctional mitochondria by mitophagy. Given the immunogenicity of mitochondrial and bacterial membranes that are released during sterile and pathogen-induced trauma, we hypothesized that cardiolipins might function as "eat me" signals for professional phagocytes. In experiments with macrophage cell lines and primary macrophages, we found that membranes with mitochondrial or bacterial cardiolipins on their surface were engulfed through phagocytosis, which depended on the scavenger receptor CD36. Distinct from this process, the copresentation of cardiolipin with the Toll-like receptor 4 (TLR4) agonist lipopolysaccharide dampened TLR4-stimulated production of cytokines. These data suggest that externalized, extracellular cardiolipins play a dual role in host-host and host-pathogen interactions by promoting phagocytosis and attenuating inflammatory immune responses.

Acute postoperative inflammatory polyarthritis associated with a lone IgM cardiolipin antibody.

While the most recognised complication after joint surgery is septic arthritis, other forms of joint pathology may occur. We present a case of postoperative polyarthritis with high inflammatory markers, which responded to a course of prednisolone. The occurrence of high IgM cardiolipin antibodies that normalised with treatment suggests that this condition is a form of transient autoimmunity.

Is Increase of Homocysteine, Anti-Cardiolipin, Anti-Phospholipid Antibodies associated with Breast Tumors?

Patients with malignancy are at higher risk of thrombotic complications due to the hypercoagulability state. Our objective in this study was to assess the serum concentrations of Homocysteine, anti phospholipid antibodies, and anti cardiolipin in patients with benign and malignant breast tumors and study the effect of chemotherapy on the serum levels of these markers. A case control study was carried out on 100 women with malignant breast tumor and 100 age matched control with benign breast tumors.Serum concentrations of heomocystein, anti cardiolipin antibody (IgG and IgMaCL) and anti-phospholipid antibody (IgG and IgMaPL) were measured in all cases. The malignant group was followed for six months, and serum levels of above-mentioned markers were measured again after surgical removal of breast tumor and chemotherapy. Current results showed a significantly higher serum concentration of Homocysteine, IgG and IgMaPL, IgG and IgM aCL in patients with malignant tumor before chemotherapy compared with benign tumor patients. We found a significant decrease in these markers after chemotherapy (P Value<0.05).We propose performing these tests (Homocysteine, IgG and IgM aPL, aCL) in patients with breast malignancy and starting prophylactic anti-thrombotic treatment in those with high serum levels of the markers. In addition, since the serum levels of the markers in patients with malignancy reduce after adjuvant therapies, we strongly recommend using adjuvant chemotherapy in these patients.

Antiphospholipid antibodies during 6-month treatment with infliximab: a preliminary report.

BACKGROUND: The introduction of tumor necrosis factor (TNF) antagonists (adalimumab, infliximab, and etanercept) was a major advance and was highly important and beneficial in most rheumatoid arthritis (RA) patients. The adverse effects of this treatment are infrequent, but include opportunistic intracellular infection (especially the reactivation of latent Mycobacterium tuberculosis); exacerbation of demyelinating disorders; and the production of various types of antibodies such as antinuclear antibodies (ANA) or double-stranded DNA autoantibodies (dsDNA) and antiphospholipid antibodies (aPL) such as anti-cardiolipin antibodies (aCL) and anti-B2GP-I antibodies (B2GP-I). The aim of the study was to determine the prevalence of aCL and B2GP-I in IgM and IgG classes, using ELISA tests, during 6 months of follow-up in patients with refractory RA successfully treated with infliximab. MATERIAL/METHODS: We determined the prevalence of aCL and B2GP-I in IgM and IgG classes, using ELISA tests, during 6 months of follow-up in patients with refractory RA successfully treated with infliximab. RESULTS: We observed a statistically important increase only in the group of B2GP-I IgM (p<0.05). There are contradictory results concerning the ability of infliximab to induce aPL, but most authors confirm this phenomenon. CONCLUSIONS: Further investigations are needed to determine if the new aPL appears in patients with ß2-GPI gene polymorphisms such as leucine-to-valine substitution at position 247, which can lead to a conformational changes in ß2-GPI protein, leading to aPL synthesis. The role of aPL in pathogenesis of APS is still unclear, but we should remember the immunogenic aspect of TNF antagonist treatment. Therefore, we recommend early detection of aPL and observation of the patient, paying special attention to signs and symptoms of thromboembolism.

Avaliação da agregação plaquetária em presença de anticorpos antifosfolípides: anti-β2GP1 e anticardiolipina / Evaluation of platelet aggregation in the presence of antiphospholipid antibodies: anti-β2GP1 and anticardiolipin

INTRODUÇÃO: A síndrome antifosfolípide (SAF) é uma condição autoimune que apresenta fenômenos trombóticos arteriais e venosos de repetição além de complicações obstétricas. Sua patogênese está associada à presença de anticorpos antifosfolípides e/ou anti-β2 glicoproteína I (β2GPI) que aparentemente modificam o efeito anticoagulante da β2GPI. A dimerização da β2GPI induzida por anticorpos parece estar relacionada à indução da agregação plaquetária contribuindo para o estado trombofílico na SAF. OBJETIVOS: O presente trabalho objetiva demonstrar a influencia dos anticorpos antifosfolípides em testes de agregação plaquetária com diferentes agonistas (ADP, colágeno e adrenalina). MÉTODOS: Foram analisados testes de agregação de plaquetas normais com diferentes agonistas (ADP, colágeno, adrenalina) na presença de soro contendo anticorpos antifosfolípides em diferentes concentrações. RESULTADOS: As análises obtidas mostraram uma inibição significativa (P < 0,05) nas curvas de agregação plaquetária induzidas por ADP e adrenalina quando comparadas ao controle. O paradoxo entre o estado protrombótico e a presença de autoanticorpos que in vitro apresentam atividade anticoagulante foi demonstrado na literatura, dificultando o entendimento patofisiológico da síndrome antifosfolípide. CONCLUSÃO: Os resultados obtidos demonstraram que o soro rico em anticorpos anticardiolipina e anti-β2GPI, ambas da classe IgG, interferem em testes de curvas de agregação plaquetária.

INTRODUCTION: The antiphospholipid syndrome (APS) is an autoimmune condition characterized by recurrent arterial and venous thrombosis, besides obstetric complications. The pathogenesis is associated with the presence of antiphospholipid and/or anti-b2-glicoprotein I (anti-b2GPI) antibodies that appear to change the anticoagulant activity of b2GPI. Antibody-induced dimerization of b2GPI seems to be related to the induction of platelet aggregation, contributing to the development of thrombosis in APS. OBJECTIVES: The objective of the present study is to demonstrate the influence of antiphospholipid antibodies in platelet aggregation tests with different agonists (ADP, collagen, and adrenaline). METHODS: We analyzed platelet aggregation tests with different agonists (ADP, collagen, adrenalin) when normal platelets were exposed to serum with different concentrations of antiphospholipid antibodies. RESULTS: Results demonstrated a significant inhibition in adrenalin- and ADP-induced platelet aggregation curves (P < 0.05) in all antibody concentrations tested when compared to the control. The paradox between the prothrombotic state and the presence of autoantibodies that show anticoagulant activity in vitro was demonstrated in the literature, making it difficult to understand the pathophysiologic mechanism of the antiphospholipid syndrome. CONCLUSION: Results showed that anticardiolipin and anti-b2GPI antibodies-rich serum, both of which belonging to the IgG class, can interfere with platelet aggregation curves.

Diffuse lymphadenopathy as the presenting manifestation of systemic lupus erythematosus.

We report the case of a 27-year-old African American man who presented with 6 months of generalized lymphadenopathy and nothing in his history or examination to suggest systemic lupus erythematosus (SLE). He was thought to have lymphoma, syphilis, or tuberculosis, and an extensive workup was done. Laboratory investigation finally revealed leukopenia (4.0), proteinuria (1.87 g), antinuclear antibodies (640 speckled), anti-double-stranded DNA (640), anticardiolipin immunoglobulins G and M, anti-Smith, Coombs, anti-Ro, anti-La, CK (531 U/L), aldolase (8.5 U/L), high erythrocyte sedimentation rate (130 mm/h), and low complement (C3 15 mg/dL and C4 3 mg/dL). A kidney biopsy showed diffuse proliferative glomerulonephritis, International Society of Nephrology class IV. Generalized lymphadenopathy as the first and only manifestation for 6 months made the diagnosis of SLE challenging. Generalized diffuse lymphadenopathy has been associated with SLE but is much less frequent now than in the past. The differential diagnosis of lymphadenopathy relevant to rheumatologists includes Kikuchi histiocytic necrotizing lymphadenitis, Castleman disease, syphilis, tuberculosis, sarcoidosis, and lymphoma.

Mitochondrial cardiolipin is required for Nlrp3 inflammasome activation.

Nlrp3 inflammasome activation occurs in response to numerous agonists but the specific mechanism by which this takes place remains unclear. All previously evaluated activators of the Nlrp3 inflammasome induce the generation of mitochondrial reactive oxygen species (ROS), suggesting a model in which ROS is a required upstream mediator of Nlrp3 inflammasome activation. Here we have identified the oxazolidinone antibiotic linezolid as a Nlrp3 agonist that activates the Nlrp3 inflammasome independently of ROS. The pathways for ROS-dependent and ROS-independent Nlrp3 activation converged upon mitochondrial dysfunction and specifically the mitochondrial lipid cardiolipin. Cardiolipin bound to Nlrp3 directly and interference with cardiolipin synthesis specifically inhibited Nlrp3 inflammasome activation. Together these data suggest that mitochondria play a critical role in the activation of the Nlrp3 inflammasome through the direct binding of Nlrp3 to cardiolipin.

Low levels of IgM antibodies to oxidized cardiolipin increase and high levels decrease risk of cardiovascular disease among 60-year olds: a prospective study.

BACKGROUND: Antibodies against cardiolipin (aCL) are associated with increased risk of cardiovascular disease (CVD). We here determine the role of antibodies against oxidized CL (aOxCL). METHODS: One third of sixty-year olds from the Stockholm County were screened (2039 men, 2193 women), where 211 incident CVD-cases and 633 age- and sex-matched controls were identified (5-7 year follow-up). Antibodies were determined by ELISA and uptake of oxLDL in macrophages by FACScan. RESULTS: IgM aOxCL was lower among CVD cases than controls (p=0.024). aOxCL-levels were divided in quartiles with the highest quartile set as the reference group. After adjustment for smoking, BMI, type II diabetes, hypercholesterolaemia and hypertension, an increased risk was determined in the lowest quartile of IgM aOxCL (OR: 1.80, CI: 1.12-2.91, p=0.0159); OR for men in the lowest quartile was 2.46 (CI 1.34-4.53, p=0.0037) for CVD and for stroke: 12.28 (CI: 1.48-101.77, p=0.02). IgG aOxCL levels did not differ between quartiles in CVD-risk. High levels of IgM aOxCL (reaching significance above 86th) and IgG aOxCL (above 95th percentile) were associated with decreased risk of CVD (OR: 0.485, CI: 0.283-0.829; p=0.0082 and OR: 0.23, CI: 0.07-0.69; p=0.0091). aCL were not associated with CVD. oxCL but not CL competed out uptake of OxLDL in macrophages, and aOxLDL recognized oxCL but not CL. In contrast to aCL, aOxCL was not dependent on co-factor Beta2-glycoprotein-I. CONCLUSIONS: aOxCL is a novel risk/protection marker for CVD, with therapeutic implications. OxCL competes with oxLDL for uptake in macrophages and the possibility that aOxCL inhibits such uptake by interfering with same or similar epitopes in oxCL and oxLDL should be further studied.

Recognition of microbial and mammalian phospholipid antigens by NKT cells with diverse TCRs.

CD1d-restricted natural killer T (NKT) cells include two major subgroups. The most widely studied are Vα14Jα18(+) invariant NKT (iNKT) cells that recognize the prototypical α-galactosylceramide antigen, whereas the other major group uses diverse T-cell receptor (TCR) α-and ß-chains, does not recognize α-galactosylceramide, and is referred to as diverse NKT (dNKT) cells. dNKT cells play important roles during infection and autoimmunity, but the antigens they recognize remain poorly understood. Here, we identified phosphatidylglycerol (PG), diphosphatidylglycerol (DPG, or cardiolipin), and phosphatidylinositol from Mycobacterium tuberculosis or Corynebacterium glutamicum as microbial antigens that stimulated various dNKT, but not iNKT, hybridomas. dNKT hybridomas showed distinct reactivities for diverse antigens. Stimulation of dNKT hybridomas by microbial PG was independent of Toll-like receptor-mediated signaling by antigen-presenting cells and required lipid uptake and/or processing. Furthermore, microbial PG bound to CD1d molecules and plate-bound PG/CD1d complexes stimulated dNKT hybridomas, indicating direct recognition by the dNKT cell TCR. Interestingly, despite structural differences in acyl chain composition between microbial and mammalian PG and DPG, lipids from both sources stimulated dNKT hybridomas, suggesting that presentation of microbial lipids and enhanced availability of stimulatory self-lipids may both contribute to dNKT cell activation during infection.

Deterioration of thromboses in primary antiphospholipid syndrome: TNF-alpha and anti-annexin A5 antibodies.

BACKGROUND: To investigate the association between clinical and serological features of patients with primary antiphospholipid syndrome (PAPS) and TNF-alpha, interleukin 6 (IL-6), and soluble IL-2 receptor (sIL-2R). METHODS: ELISA was used for measurement of antibodies (Abs) and TNF-alpha, while IL-6 and sIL-2R were measured by chemiluminescence. RESULTS: PAPS patients with pulmonary emboli showed positive correlation between IgM isotype of anti-annexin A5 antibodies and TNF-alpha (r = 0.894, p = 0.041) and IgM class of anticardiolipin antibodies and sIL-2R (r = 0.900, p = 0.037). In PAPS with cerebrovascular insults, positive correlation was noticed between TNF-alpha and IgG isotype of anticardiolipin (r = 0.624, p = 0.040) and anti-annexinA5 Abs (r = 0.768, p = 0.006). CONCLUSIONS: Isotype analysis of antiphospholipid and anti-annexin A5 Abs and investigation of their association with TNF-alpha is important for differentiation of PAPS patients that are prone to further deterioration of arterial and venous thromboses.

Hematological features of pediatric systemic lupus erythematosus: suggesting management strategies in children.

AIM: The aim of this study was to analyze the hematological features in children with systemic lupus erythematosus (SLE) and to review our current treatment protocols. METHODS: We evaluated hematological findings of 43 children with SLE diagnosed and followed at the Pediatric Rheumatology Division of Hacettepe University, Turkey. Thirty-seven patients with hematological abnormalities were analyzed in detail. RESULTS: Median age at presentation was 13 years. Hematological involvement was seen in 86% of patients. The most common hematological finding was anemia (n = 30). Anemia was either a Coombs (+) hemolytic one, or was due to other causes. Hemolytic anemia was treated with steroids and intravenous gamma globulin (IVIG). Leucopenia and thrombocytopenia were detected in 35.1 % and 37.8 %, respectively. Bone marrow aspiration was performed in 15, mainly for cytopenia. Secondary dysplastic changes were common. Acute lymphoblastic leukemia (ALL) was diagnosed in one patient. Six patients were diagnosed as having macrophage activation syndrome (MAS). One patient died due to secondary infections and multiorgan failure despite aggressive treatment. In patients diagnosed early, treatment with steroids and cyclosporine resulted in an excellent response. Thrombotic microangiopathy was detected in two patients. Both were treated successfully with steroids and plasma exchange. Antiphospholipid and anticardiolipin antibodies were positive in 12 and 15 of the patients, respectively. Five developed deep vein thrombosis (DVT), one cerebral sinus thrombosis and one presented with purpura fulminans. They were effectively treated with anticoagulation protocol. CONCLUSION: Hematological findings should be carefully assessed and treated vigorously to prevent the morbidity and possible mortality.

The significance of anticardiolipin antibody and immunologic abnormality in livedoid vasculitis.

OBJECTIVE: To evaluate the significance of anticardiolipin and immunologic abnormality in the livedoid vasculitis (LV). METHODS: 30 patients with biopsy-proven LV and 30 normal controls involved in the study. Indirect immunofluorescence, immunoblot, and ELISA were used for detecting antinuclear antibody (ANA), circulating immune complex, immune globulin, anticardiophospholipin antibody (ACA), and anti-ß(2) GP1. RESULTS: ANA was positive in four patients with LV, and among them, two patients were diagnosed as Systemic Lupus Erythematosus (SLE) later. Addition to the two SLE patients, the level of ENA and immunoglobulin were normal in the rest of patients. Anticardiolipin antibodies were present in 13 (43.33%), and ß(2) GP1 was present in nine (30%) of 30 patients. There were significant differences between LV and controls. CONCLUSIONS: ACA is one of important pathogenesis of LV. Numerous heterogeneous coagulation abnormalities and thrombogenesis may involve the LV.