CLEVER-1 as an immune suppressive molecule

The immune response and immune suppression are equally essential for the immune system to protect the host against an infection and to protect self-molecules in different pathophysiological conditions. Pregnancy is one of the conditions where the maternal immune system remains resistant against microbes and yet attains tolerance to protect the fetus, whose genetic material differs partially from the mother’s. However, if the balance of immune suppression is not precise in the host it can favor conditions which lead to diseases, such as cancer and autoimmune disorders. This study was initiated to investigate the expression and functions of CLEVER-1/Stabilin-1, a multifunctional protein expressed on subsets of endothelial cells and type II macrophages, as an immune suppressive molecule. Firstly, the expression of CLEVER-1/stabilin-1 and its function in human placental macrophages were examined. Secondly, the expression profile and functional significance of stabilin-1 on healthy human monocytes was investigated. The results clarified the expression of CLEVER-1/stabilin-1 on placental macrophages, and verified that CLEVER-1/stabilin-1 functions as an adhesion and scavenging molecule on these cells. The data from normal monocytes revealed that the monocytes with low stabilin-1 expression carried a pro-inflammatory gene signature, and that stabilin-1 can directly or indirectly regulate pro-inflammatory genes in monocytes. Finally, it was shown that monocyte CLEVER-1/stabilin-1 dampens IFN production by T cells. To conclude, CLEVER-1/stabilin-1 is defined as an immune suppressive molecule on monocytes and macrophages. Strikingly, anti-stabilin-1 antibodies may have the potential to promote the Th1 dependent inflammatory response and counteract the tumor induced immune suppression.CLEVER-1 tulehdusreaktiota vaimentavana molekyylinä Elimistön puolustusjärjestelmä torjuu mikrobi-infektioita ja muita vieraita molekyylejä immuunivasteeksi kutsutun mekanismin avulla. Samalla immuunivasteen pitää kuitenkin suojella elimistön normaalisoluja ja kyetä palaamaan taas normaalitilaan uhkan torjumisen jälkeen. Raskaus on yksi esimerkki tilanteesta, jossa äidin immuunisysteemi säilyttää reagointikykynsä mikrobeja kohtaan samalla kun se sikiön suojelemiseksi sietää sikiön sisältämää vierasta geneettistä materiaalia. Immuuunireaktion tasapainon säätelyhäiriöt ovat osallisina syövän ja autoimmuunitautien synnyssä. CLEVER-1/stabilin-1 on tietyissä endoteelisoluissa ja makrofaageissa ilmentyvä molekyyli, joka osallistuu valkosolujen liikkumiseen ja vieraiden molekyylien tunnistamiseen. Tässä työssä selvitin CLEVER-1/stabilin-1:n ilmentymistä ja toimintaa ihmisen veren monosyyteissä ja istukan makrofageissa. Väitöskirjatyön tulokset osoittivat, että CLEVER-1/stabilin-1 ilmenee istukan kaikissa makrofageissa ja että se toimii näissä soluissa sekä tarttumismolekyylinä että ns. scavenging-molekyylinä. Normaaleilla monosyyteillä tehdyt tutkimukset paljastivat, että niukasti CLEVER-1/stabilin-1 molekyyliä ilmentävät solut olivat tulehduksellisesti aktiivisempia kuin runsaasti CLEVER-1/stabilin-1:tä ilmentävät solut. Lisäksi kokeissa pystyttiin osoittamaan, että monosyyttien CLEVER-1/Stabilin-1 säätelee tulehdusta vahvistavien geenien ilmentymistä monosyyteissä ja tulehduksen välittäjäaineiden (gamma-interferoni) tuottoa T-soluissa. Väitöskirjatyöni osoittaa, että CLEVER-1/stabilin-1 on immunosuppressiivinen molekyyli monosyyteissä ja makrofageissa. CLEVER-1/stabilin-1- vasta-aineilla voisikin olla mahdollista tehostaa interferoni-gamma riippuvaista tulehdusvastetta ja näin kumota syövän aiheuttamaa immunosuppressiota.Siirretty Doriast

A study on tuberculosis disease disclosure patterns and its associated factors: Findings from a prospective observational study in Chennai

BACKGROUND: Disclosure of tuberculosis (TB) status by patients is a critical step in their treatment cascade of care. There is a lack of systematic assessment of TB disclosure patterns and its positive outcomes which happens dynamically over the disease period of individual patients with their family and wider social network relations. METHODS: This prospective observational study was conducted in Chennai Corporation treatment units during 2019–2021. TB patients were recruited and followed-up from treatment initiation to completion. Information on disease disclosures made to different social members at different time points, and outcomes were collected and compared. Bivariate and multi variate analysis were used to identify the patients and contact characteristics predictive of TB disclosure status. RESULTS: A total of 466 TB patients were followed-up, who listed a total of 4039 family, extra familial and social network contacts of them. Maximum disclosures were made with family members (93%) and half of the relatives, occupational contacts and friendship contacts (44–58%) were disclosed within 15 days of treatment initiation. Incremental disclosures made during the 150–180 days of treatment were highest among neighbourhood contacts (12%), and was significantly different between treatment initiation and completion period. Middle aged TB patients (31 years and 46–55 years) were found less likely to disclose (AOR 0.56 and 0.46 respectively; p71%). CONCLUSION: Findings explain that family level disclosures were predominant and disclosures made to extra familial network contacts significantly increased during the latter part of treatment. Emotional support was predominantly received by TB patients from all their contacts post disclosure. Findings could inform in developing interventions to facilitate disclosure of disease status in a beneficial way for TB patients

[C-11]carfentanil PET imaging for studying the peripheral opioid system in vivo : effect of photoperiod on mu-opioid receptor availability in brown adipose tissue

Purpose Photoperiod determines the metabolic activity of brown adipose tissue (BAT) and affects the food intake and body mass of mammals. Sympathetic innervation of the BAT controls thermogenesis and facilitates physiological adaption to seasonal changes, but the exact mechanism remains elusive. Previous studies have shown that central opioid signaling regulates BAT thermogenesis, and that the expression of the brain mu-opioid receptor (MOR) varies seasonally. Therefore, it is important to know whether MOR expression in BAT shows seasonal variation. Methods We determined the effect of photoperiod on BAT MOR availability using [C-11] carfentanil positron emission tomography (PET). Adult rats (n = 9) were repeatedly imaged under various photoperiods in order to simulate seasonal changes. Results Long photoperiod was associated with low MOR expression in BAT (beta = -0.04, 95% confidence interval: - 0.07, - 0.01), but not in muscles. We confirmed the expression of MOR in BAT and muscle using immunofluorescence staining. Conclusion Photoperiod affects MOR availability in BAT. Sympathetic innervation of BAT may influence thermogenesis via the peripheral MOR system. The present study supports the utility of [C-11]carfentanil PET to study the peripheral MOR system.Peer reviewe

Exploiting Glutamine Consumption in Atherosclerotic Lesions by Positron Emission Tomography Tracer (2S,4R)-4-F-18-Fluoroglutamine

Increased glutamine metabolism by macrophages is associated with development of atherosclerotic lesions. Positron emission tomography/computed tomography (PET/CT) with a glutamine analog (2S,4R)-4-F-18-fluoroglutamine (F-18-FGln) allows quantification of glutamine consumption in vivo. Here, we investigated uptake of F-18-FGln by atherosclerotic lesions in mice and compared the results with those obtained using the glucose analog 2-deoxy-2-F-18-fluoro-D-glucose (F-18-FDG). Uptake of F-18-FGln and F-18-FDG by healthy control mice (C57BL/6JRj) and atherosclerotic low-density lipoprotein receptor-deficient mice expressing only apolipoprotein B100 (LDLR(-/-)ApoB(100/100)) was investigated. The mice were injected intravenously with F-18-FGln or F-18-FDG for in vivo PET/CT imaging. After sacrifice at 70 minutes post-injection, tracer uptake was analyzed by gamma counting of excised tissues and by autoradiography of aorta cryosections, together with histological and immunohistochemical analyses. We found that myocardial uptake of F-18-FGln was low. PET/CT detected lesions in the aortic arch, with a target-to-background ratio (SUVmax, aortic arch/SUVmean, blood) of 1.95 +/- 0.42 (mean +/- standard deviation). Gamma counting revealed that aortic uptake of F-18-FGln by LDLR(-/-)ApoB(100/100) mice (standardized uptake value [SUV], 0.35 +/- 0.06) was significantly higher than that by healthy controls (0.20 +/- 0.08, P = 0.03). More detailed analysis by autoradiography revealed that the plaque-to-healthy vessel wall ratio of F-18-FGln (2.90 +/- 0.42) was significantly higher than that of F-18-FDG (1.93 +/- 0.22, P = 0.004). Immunohistochemical staining confirmed that F-18-FGln uptake in plaques co-localized with glutamine transporter SLC7A7-positive macrophages. Collectively these data show that the F-18-FGln PET tracer detects inflamed atherosclerotic lesions. Thus, exploiting glutamine consumption using F-18-FGln PET may have translational relevance for studying atherosclerotic inflammation

Preclinical Evaluation of a Humanized Antibody Against Common Lymphatic Endothelial and Vascular Endothelial Receptor-1, 89Zr-Desferrioxamine-Bexmarilimab, in a Rabbit Model of Renal Fibrosis

Bexmarilimab is a new humanized monoclonal antibody against common lymphatic endothelial and vascular endothelial receptor-1 (CLEVER-1), and is in clinical trials for macrophage-guided cancer immunotherapy. In addition to cancer, CLEVER-1 is also associated with fibrosis. To facilitate prospective human PET studies, we preclinically evaluated 89Zr-labeled bexmarilimab in rabbits. Methods: Bexmarilimab was conjugated with desferrioxamine (DFO) and radiolabeled with 89Zr. Retained immunoreactivity was confirmed by flow cytometry. Distribution kinetics of intravenously administered 89Zr-DFO-bexmarilimab (0.1 mg/kg) for up to 7 days in a rabbit model of renal fibrosis mediated by unilateral ureteric obstruction (UUO). The in-vivo stability of 89Zr-DFO-bexmarilimab was evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in combination with autoradiography. Additionally, we estimated the human radiation dose from data obtained in healthy rabbits. Results: 89Zr-DFO-bexmarilimab cleared rapidly from the blood circulation and distributed to the liver and spleen. At 24 hours post-injection, PET/CT, ex-vivo gamma counting and autoradiography demonstrated that there was significantly higher 89Zr-DFO-bexmarilimab uptake in UUO-operated fibrotic renal cortex, characterized by abundant CLEVER-1-positive cells, than in contralateral or healthy kidneys. The estimated effective dose for a 70-kg human was 0.70 mSv/MBq. Conclusion: The characteristics of 89Zr-DFO-bexmarilimab support future human PET studies to, for example, stratify patients for bexmarilimab treatment, evaluate the efficacy of treatment, or monitor disease progression.</p

[11C]carfentanil PET imaging for studying the peripheral opioid system in vivo: effect of photoperiod on mu-opioid receptor availability in brown adipose tissue

Purpose Photoperiod determines the metabolic activity of brown adipose tissue (BAT) and affects the food intake and body mass of mammals. Sympathetic innervation of the BAT controls thermogenesis and facilitates physiological adaption to seasonal changes, but the exact mechanism remains elusive. Previous studies have shown that central opioid signaling regulates BAT thermogenesis, and that the expression of the brain mu-opioid receptor (MOR) varies seasonally. Therefore, it is important to know whether MOR expression in BAT shows seasonal variation.Methods We determined the effect of photoperiod on BAT MOR availability using [C-11] carfentanil positron emission tomography (PET). Adult rats (n = 9) were repeatedly imaged under various photoperiods in order to simulate seasonal changes.Results Long photoperiod was associated with low MOR expression in BAT (beta = -0.04, 95% confidence interval: - 0.07, - 0.01), but not in muscles. We confirmed the expression of MOR in BAT and muscle using immunofluorescence staining.Conclusion Photoperiod affects MOR availability in BAT. Sympathetic innervation of BAT may influence thermogenesis via the peripheral MOR system. The present study supports the utility of [C-11]carfentanil PET to study the peripheral MOR system.</p

Dissecting the polygenic basis of atherosclerosis via disease-associated cell state signatures

Coronary artery disease (CAD) is a pandemic disease where up to half of the risk is explained by genetic factors. Advanced insights into the genetic basis of CAD require deeper understanding of the contributions of different cell types, molecular pathways, and genes to disease heritability. Here, we investigate the biological diversity of atherosclerosis-associated cell states and interrogate their contribution to the genetic risk of CAD by using single-cell and bulk RNA sequencing (RNA-seq) of mouse and human lesions. We identified 12 disease-associated cell states that we characterized further by gene set functional profiling, ligand-receptor prediction, and transcription factor inference. Importantly, Vcam1+ smooth muscle cell state genes contributed most to SNP-based heritability of CAD. In line with this, genetic variants near smooth muscle cell state genes and regulatory elements explained the largest fraction of CAD-risk variance between individuals. Using this information for variant prioritization, we derived a hybrid polygenic risk score (PRS) that demonstrated improved performance over a classical PRS. Our results provide insights into the biological mechanisms associated with CAD risk, which could make a promising contribution to precision medicine and tailored therapeutic interventions in the future.publishedVersionPeer reviewe