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IntroductionUpon infection,T cell-driven B cell responses in GC reactions induce memory B cells and antibody-secreting cells that secrete protective antibodies. How formation of specifically long-lived plasma cells is regulated via the interplay between specific B and CD4+ T cells is not well understood. Generally,antibody levels decline over time after clearance of the primary infection.MethodIn this study,convalescent individuals with stable RBD antibody levels (n=14,“sustainers”) were compared with donors (n=13) with the greatest antibody decline from a cohort of 132. To investigate the role of the cellular immune compartment in the maintenance of antibody levels,SARS-CoV-2-specific responses at 4 to 6 weeks post-mild COVID-19 infection were characterized using deep immune profiling.ResultsBoth groups had similar frequencies of total SARS-CoV-2-specific B and CD4+ T cells. Sustainers had fewer Spike-specific IgG+ memory B cells early after infection and increased neutralizing capacity of RBD antibodies over time,unlike the declining group. However,declining IgG titers correlated with lower frequency of Spike-specific CD4+ T cells.ConclusionThese data suggest that “sustainers” have unique dynamics of GC reactions,yield different outputs of terminally differentiating cells,and improve the quality of protective antibodies over time. This study helps identify factors controlling formation of long-lived PC and sustained antibody responses. View Publication

The lungs of people with cystic fibrosis (PwCF) are characterized by recurrent bacterial infections and inflammation. Infections in cystic fibrosis (CF) are left unresolved despite excessive neutrophil infiltration. The role of CFTR in neutrophils is not fully understood. In this study,we aimed to assess which antimicrobial functions are directly impaired by loss of CFTR function in neutrophils. In order to do so,we used a specific inhibitor of CFTR ion channel activity,inh-172. CF neutrophils from PwCF harboring severe CFTR mutations were additionally isolated to further discern CFTR-specific functional defects. We evaluated phagocytosis,reactive oxygen species (ROS) production,neutrophil elastase (NE) and myeloperoxidase (MPO) exocytosis and bacterial killing. The inh-172 model identified decreased acidification of the phagosome,increased bacterial survival and decreased ROS production upon stimulation. In PwCF neutrophils,we observed reduced degranulation of both NE and MPO. When co-culturing neutrophils with CF sputum supernatant and airway epithelial cells,the extent of phagocytosis was reduced,underscoring the importance of recreating an inflammatory environment as seen in PwCF lungs to model immune responses in vitro. Despite low CFTR expression in blood neutrophils,functional defects were found in inh-172-treated and CF neutrophils. The inh-172 model disregards donor variability and allows pinpointing neutrophil functions directly impaired by dysfunctional CFTR.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-024-82535-z. View Publication

AbstractChlamydia genital infection caused by Chlamydia trachomatis is the most common bacterial sexually transmitted disease worldwide. A mouse model has been developed in our laboratory to better understand the effect of cold-induced stress on chlamydia genital infection and immune response. However,the stress mechanism affecting the host response to Chlamydia muridarum genital infection remains unclear. Here,we demonstrate a role for the beta2-adrenergic receptor (β2-AR),which binds noradrenaline and modulates the immune response against chlamydia genital infection in a mouse model. A successful β2-AR homozygous knockout (KO) mouse model was used to study the infection and analyze the immune response. Our data show that stressed mice lacking the β2-AR are less susceptible to C. muridarum genital infection than controls. A correlation was obtained between lower organ load and higher interferon-gamma production by CD4+ and CD8+ cells of the KO mice. Furthermore,exposure of CD4+ T cells to noradrenaline alters the production of cytokines in mice during C. muridarum genital infection. This study suggests that the blockade of β2-AR signaling could be used to increase resistance to chlamydia genital infection. We value the β2-AR KO as a viable model that can provide reproducible results in investigating medical research,including chlamydia genital infection. Deficiency in a receptor leads to a reduced disease of chlamydia in a mouse model. View Publication

Eosinophils,a type of granulocyte derived from myeloid precursors in the bone marrow,are distinguished by their cytoplasmic granules. They play crucial roles in immunoregulation,tissue homeostasis,and host defense,while also contributing to the pathogenesis of various inflammatory diseases. Although long non-coding RNAs (lncRNAs) are known to be involved in eosinophilic conditions,their specific expression and functions within eosinophils have not been thoroughly investigated,largely due to the reliance on tissue homogenates. In an effort to address this gap,we analyzed publicly available high-throughput RNA sequencing data to identify lncRNAs associated with eosinophilic conditions. Among the identified lncRNAs,ITGB2 antisense RNA 1 (ITGB2-AS1) was significantly downregulated in blood eosinophils from patients with hypereosinophilia. To further explore its role in eosinophil biology,we generated a stable ITGB2-AS1 knockdown in the HL-60 cell line. Interestingly,ITGB2-AS1 deficiency led to impaired eosinophil differentiation,as evidenced by a reduction in cytoplasmic granules and decreased expression of key eosinophil granule proteins,including eosinophil peroxidase (EPX) and major basic protein-1 (MBP-1). Additionally,ITGB2-AS1-deficient cells exhibited compromised eosinophil effector functions,with reduced degranulation and impaired production of reactive oxygen species (ROS). These findings suggest that ITGB2-AS1 plays a pivotal role in eosinophil differentiation and function,positioning it as a novel regulator in eosinophil biology. View Publication

IntroductionSystemic sclerosis (SSc) is a complex autoimmune connective tissue disease characterized by microvascular damage,immune system reactivity and progressive fibrosis of skin and internal organs. Interstitial lung disease is the leading cause of death for SSc patients (SSc-ILD),and the process of lung fibrosis involves also circulating monocytes and alveolar macrophages.MethodsCurrent study aimed to identify monocyte/macrophage phenotypes in lung and peripheral blood of SSc-ILD patients by immunostaining and flow cytometry,respectively. Single immunostaining was performed using primary antibodies against CD68 (pan-macrophage marker),CD80,CD86,TLR4 (M1 markers),CD163,CD204,and CD206 (M2 markers). Flow cytometry analysis included the evaluation of CD45,CD14,CD16 (monocyte lineage),CD1c (dendritic lineage),together with M1 and M2 activation markers on circulating monocytes. Protein synthesis of TLR4 and M2 markers was also investigated in cultured monocytes-derived macrophages (MDMs) from SSc-ILD patients by Western Blotting.ResultsLung samples were obtained from 9 SSc-ILD patients (50 ± 9 years old) and 5 control non-SSc patients without lung fibrosis (58 ± 23 years old). Alveolar macrophages (CD68+ cells) showed a significantly higher positivity of M1 and M2 markers in SSc-ILD lung samples than in controls (p<0.05 for CD80,p<0.01 for CD86,p<0.001 for CD68,p<0.0001 for TLR4,CD163,CD204 and CD206). In CD68 positive areas of SSc-ILD samples,a significantly higher percentage of TLR4,CD163,CD204,and CD206 positive cells was observed compared to CD80 and CD86 positive cells (p<0.001 in both cases),suggesting the possible presence of hybrid TLR4+M2 macrophages (CD68+CD80-CD86-TLR4+CD163+CD204+CD206+cells) in SSc-ILD samples. A second cohort of 26 SSc-ILD patients (63 ± 14 years old) and 14 SSc patients without ILD (63 ± 19 years old) was recruited for flow cytometry analysis of circulating monocytes. Again,a significantly higher percentage of hybrid TLR4+M2 monocytes (CD1c-CD80-TLR4+CD163+CD204+CD206+cells) was found in SSc-ILD positive than SSc-ILD negative patients (p<0.05). Moreover,the protein synthesis of TLR4 and M2 markers was also found higher in cultured MDMs obtained from SSc-ILD patients than in MDMs from SSc patients without ILD and this increase was significantly higher for CD163 (p<0.05) and CD206 (p<0.01).ConclusionsThe presence of hybrid TLR4+M2 markers on both circulating monocytes and resident lung macrophages in SSc-ILD patients,is reported for the first time. Therefore,the detection of circulating hybrid TLR4+M2 monocytes in SSc-ILD might represent a further potential biomarker of progressive organ fibrosis,to be searched in blood samples of SSc patients. View Publication

Background: Preclinical cell tracking is enhanced with a multimodal imaging approach. Bioluminescence imaging (BLI) is a highly sensitive optical modality that relies on engineering cells to constitutively express a luciferase gene. Magnetic particle imaging (MPI) is a newer imaging modality that directly detects superparamagnetic iron oxide (SPIO) particles used to label cells. Here,we compare BLI and MPI for imaging cells in vitro and in vivo. Methods: Mouse 4T1 breast carcinoma cells were transduced to express firefly luciferase,labeled with SPIO (ProMag),and imaged as cell samples after subcutaneous injection into mice. Results: For cell samples,the BLI and MPI signals were strongly correlated with cell number. Both modalities presented limitations for imaging cells in vivo. For BLI,weak signal penetration,signal attenuation,and scattering prevented the detection of cells for mice with hair and for cells far from the tissue surface. For MPI,background signals obscured the detection of low cell numbers due to the limited dynamic range,and cell numbers could not be accurately quantified from in vivo images. Conclusions: It is important to understand the shortcomings of these imaging modalities to develop strategies to improve cellular detection sensitivity. View Publication

In the pathophysiology of osteoarthritis and osteoporosis,articular cartilage and bone represent the target tissues,respectively,but muscle is also involved. Since many changes in energy metabolism occur in muscle with aging,the aim of the present work was to investigate the involvement of carnitine palmitoyl transferase 1b (Cpt1b) in the muscle pathophysiology of the two diseases. Healthy subjects (CTR,n = 5),osteoarthritic (OA,n = 10),and osteoporotic (OP,n = 10) patients were enrolled. Gene expression analysis conducted on muscle and myoblasts showed up-regulation of CPT1B in OA patients; this result was confirmed by immunohistochemical and immunofluorescence analyses and enzyme activity assay,which showed increased Cpt1b activity in OA muscle. In addition,CPT1B expression resulted down-regulated in cultured OP myoblasts. Given the potential involvement of Cpt1b in the modulation of oxidative stress,we investigated ROS levels,which were found to be lower in OA myoblasts,and gene expression of nicotinamide adenine dinucleotide phosphate hydrogen oxidase 4 (Nox4),which resulted up-regulated in OA cells. Finally,the immunofluorescence of BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (Bnip3) showed a decreased expression in OP myoblasts,with respect to CTR and OA. Contextually,through an ultrastructural analysis conducted by Transmission Electron Microscopy (TEM),the presence of aberrant mitochondria was observed in OP muscle. This study highlights the potential role of Cpt1b in the regulation of muscle homeostasis in both osteoarthritis and osteoporosis,allowing for the expansion of the current knowledge of what are the molecular biological pathways involved in the regulation of muscle physiology in both diseases. View Publication

Introduction: The maintenance of intestinal homeostasis depends on a complex interaction between the immune system,intestinal epithelial barrier,and microbiota. Alteration in one of these components could lead to the development of inflammatory bowel diseases (IBD). Variants within the autophagy gene ATG16L1 have been implicated in susceptibility and severity of Crohn's disease (CD). Individuals carrying the risk ATG16L1 T300A variant have higher caspase 3-dependent degradation of ATG16L1 resulting in impaired autophagy and increased cellular stress. ATG16L1-deficiency induces enhanced IL-1β secretion in dendritic cells in response to bacterial infection. Infection of ATG16L1-deficient mice with a persistent strain of murine norovirus renders these mice highly susceptible to dextran sulfate sodium colitis. Moreover,persistent norovirus infection leads to intestinal virus specific CD8+ T cells responses. Both Toll-like receptor 7 (TLR7),which recognizes single-stranded RNA viruses,and ATG16L1,which facilitates the delivery of viral nucleic acids to the autolysosome endosome,are required for anti-viral immune responses. Results and discussion: However,the role of the enteric virome in IBD is still poorly understood. Here,we investigate the role of TLR7 and ATG16L1 in intestinal homeostasis and inflammation. At steady state,Tlr7-/- mice have a significant increase in large intestinal lamina propria (LP) granzyme B+ tissue-resident memory CD8+ T (TRM) cells compared to WT mice,reminiscent of persistent norovirus infection. Deletion of Atg16l1 in myeloid (Atg16l1ΔLyz2 ) or dendritic cells (Atg16l1ΔCd11c ) leads to a similar increase of LP TRM. Furthermore,Tlr7-/- and Atg16l1ΔCd11c mice were more susceptible to dextran sulfate sodium colitis with an increase in disease activity index,histoscore,and increased secretion of IFN-γ and TNF-α. Treatment of Atg16l1ΔCd11c mice with the TLR7 agonist Imiquimod attenuated colonic inflammation in these mice. Our data demonstrate that ATG16L1-deficiency in myeloid and dendritic cells leads to an increase in LP TRM and consequently to increased susceptibility to colitis by impairing the recognition of enteric viruses by TLR7. Conclusion: In conclusion,the convergence of ATG16L1 and TLR7 signaling pathways plays an important role in the immune response to intestinal viruses. Our data suggest that activation of the TLR7 signaling pathway could be an attractive therapeutic target for CD patients with ATG16L1 risk variants. View Publication

The development and progression of chronic lymphocytic leukemia (CLL) depend on genetic abnormalities and on the immunosuppressive microenvironment. We have explored the possibility that genetic drivers might be responsible for the immune cell dysregulation that shapes the protumor microenvironment. We performed a transcriptome analysis of coding and non-coding RNAs (ncRNAs) during leukemia progression in the Rag2−/−γc−/− MEC1-based xenotransplantation model. The DLEU2/miR-16 locus was found downmodulated in monocytes/macrophages of leukemic mice. To validate the role of this cluster in the tumor immune microenvironment,we generated a mouse model that simultaneously mimics the overexpression of hTCL1 and the germline deletion of the minimal deleted region (MDR) encoding the DLEU2/miR-15a/miR-16-1 cluster. This model provides an innovative and faster CLL system where monocyte differentiation and macrophage polarization are exacerbated,and T-cells are dysfunctional. MDR deletion inversely correlates with the levels of predicted target proteins including BCL2 and PD1/PD-L1 on murine CLL cells and immune cells. The inverse correlation of miR-15a/miR-16-1 with target proteins has been confirmed on patient-derived immune cells. Forced expression of miR-16-1 interferes with monocyte differentiation into tumor-associated macrophages,indicating that selected ncRNAs drive the protumor phenotype of non-malignant immune cells. View Publication

Sensory neurons sense pathogenic infiltration to drive innate immune responses,but their role in humoral immunity is unclear. Here,using mouse models of Streptococcus pneumoniae infection and Alternaria alternata asthma,we show that sensory neurons are required for B cell recruitment and antibody production. In response to S. pneumoniae,sensory neuron depletion increases bacterial burden and reduces B cell numbers,IgG release,and neutrophil stimulation. Meanwhile,during A. alternata-induced airway inflammation,sensory neuron depletion decreases B cell population sizes,IgE levels,and asthmatic characteristics. Mechanistically,during bacterial infection,sensory neurons preferentially release vasoactive intestinal polypeptide (VIP). In response to asthma,sensory neurons release substance P. Administration of VIP into sensory neuron-depleted mice suppresses bacterial burden,while VIPR1 deficiency increases infection. Similarly,exogenous substance P delivery aggravates asthma in sensory neuron-depleted mice,while substance P deficiency ameliorates asthma. Our data,thus demonstrate that sensory neurons release select neuropeptides which target B cells dependent on the immunogen. Sensory neurons may regulate innate immune cells,but their roles in humoral immunity is still unclear. Here the authors show that bacterial infection and asthma induction induce sensory neuron production of distinct neurotransmitters to dampen B cell responses but differentially target IgG and IgE,respectively,to specifically modulate the symptoms. View Publication

Neutrophil dysfunction is a form of immune suppression in patients with β-thalassemia (Beta-thal),although data on this are limited. In this study,blood from patients and healthy volunteers was analyzed. Flow cytometry analysis demonstrated an increase in immature neutrophils (CD16− CD62L+) and aged (senescent) neutrophils (CD16+ CD62L−) in Beta-thal patients compared to healthy volunteers. The Beta-thal neutrophils demonstrated less prominent chemotaxis and phagocytosis than healthy neutrophils at the baseline. With phorbol myristate acetate (PMA) or lipopolysaccharide (LPS) stimulations,some of the indicators,including the flow cytometry markers (CD11b,CD62L,CD66b,CD63,apoptosis,and reactive oxygen species) and neutrophil extracellular traps (NETs; detected by anti-citrullinated histone 3 immunofluorescence),were lower than the control. Additionally,low-density neutrophils (LDNs),which are found in the peripheral blood mononuclear cell (PBMC) fraction,were observed in Beta-thal patients but not in the control group. The expression of CD11b,CD66b,CD63,arginase I,and ROS in LDNs was higher than the regular normal-density neutrophils (NDNs). The proliferation rate of CD3+ T cells isolated from the PBMC fraction of healthy volunteers was higher than that of the cells from patients with Beta-thal. The incubation of red blood cell (RBC) lysate plus ferric ions with healthy NDNs transformed the NDNs into the aged neutrophils (decreased CD62L) and LDNs. In conclusion,iron overload induces neutrophil diversity along with some dysfunctions. View Publication

BackgroundMonocytes comprise subsets of classical,intermediate and non-classical monocytes with distinct anti- or pro-tumor effects in breast cancer (BC). They are modulated by estrogen,and can contribute to BC control by endocrine therapy in preclinical models.MethodsTo elucidate whether changes in monocyte subsets are associated with treatment and response,we investigated peripheral blood samples of 73 postmenopausal women with estrogen receptor (ER) positive BC,who received aromatase inhibitor therapy with or without the mucin-1 vaccine tecemotide in the ABCSG34 trial. Blood was retrieved at baseline,midterm and end of therapy,and was analyzed for the distribution and ER expression of monocyte subsets by flow cytometry.ResultsWhen 40 healthy,age-matched women were compared with BC patients before treatment start,ER levels of monocytes did not differ,yet patients presented with a higher frequency of classical and fewer non-classical monocytes. Endocrine therapy triggered a significant increase in ER levels in all monocyte subsets,without affecting subset distribution. Vaccination had no overall impact on subset frequency and ER expression. Yet,a shift from intermediate to classical monocytes during therapy correlated with changes in plasma cytokines and chemokines and was significantly associated with low residual cancer burden in vaccinated patients. Without tecemotide,baseline ER levels in classical monocytes were significantly higher in women with good response to endocrine therapy.ConclusionsThis study identified classical monocytes to be associated with ER positive BC and with patient response to neoadjuvant endocrine treatment and cancer vaccination.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12967-024-05659-w. View Publication