Flvcr1a deficiency promotes heme-based energy metabolism dysfunction in skeletal muscle

The definition of cell metabolic profile is essential to ensure skeletal muscle fiber heterogeneity and to achieve a proper equilibrium between the self-renewal and commitment of satellite stem cells. Heme sustains several biological functions, including processes profoundly implicated with cell metabolism. The skeletal muscle is a significant heme-producing body compartment, but the consequences of impaired heme homeostasis on this tissue have been poorly investigated. Here, we generate a skeletal-muscle-specific feline leukemia virus subgroup C receptor 1a (FLVCR1a) knockout mouse model and show that, by sustaining heme synthesis, FLVCR1a contributes to determine the energy phenotype in skeletal muscle cells and to modulate satellite cell differentiation and muscle regeneration.

Incidence, microbiological and immunological characteristics of ventilator-associated pneumonia assessed by bronchoalveolar lavage and endotracheal aspirate in a prospective cohort of COVID-19 patients: CoV-AP study

BACKGROUND

No univocal recommendation exists for microbiological diagnosis of ventilator-associated pneumonia (VAP). Sampling of either proximal or distal respiratory tract likely impacts on the broad range of VAP incidence between cohorts. Immune biomarkers to rule-in/rule-out VAP diagnosis, although promising, have not yet been validated. COVID-19-induced ARDS made VAP recognition even more challenging, often leading to overdiagnosis and overtreatment. We evaluated the impact of different respiratory samples and laboratory techniques on VAP incidence and microbiological findings in COVID-19 patients.

METHODS

Prospective single-centre cohort study conducted among COVID-19 mechanically ventilated patients in Policlinico Hospital (Milan, Italy) from January 2021 to May 2022. Microbiological confirmation of suspected VAP (sVAP) was based on concomitant endotracheal aspirates (ETA) and bronchoalveolar lavage (BAL). Conventional and fast microbiology (FILMARRAY® Pneumonia Panel plus, BALFAPPP) as well as immunological markers (immune cells and inflammatory cytokines) was analysed.

RESULTS

Seventy-nine patients were included. Exposure to antibiotics and steroid therapy before ICU admission occurred in 51/79 (64.6%) and 60/79 (65.9%) patients, respectively. Median duration of MV at VAP suspicion was 6 (5-9) days. Incidence rate of microbiologically confirmed VAP was 33.1 (95% CI 22.1-44.0) and 20.1 (95% CI 12.5-27.7) according to ETA and BAL, respectively. Concordance between ETA and BAL was observed in 35/49 (71.4%) cases, concordance between BALFAPPP and BAL in 39/49 (79.6%) cases. With BAL as reference standard, ETA showed 88.9% (95% CI 70.8-97.7) sensitivity and 50.0% (95% CI 28.2-71.8) specificity (Cohen's Kappa 0.40, 95% CI 0.16-0.65). BALFAPPP showed 95.0% (95% CI 75.1-99.9) sensitivity and 69% (95% CI 49.2-84.7) specificity (Cohen's Kappa 0.60, 95% CI 0.39-0.81). BAL IL-1β differed significantly between VAP (135 (IQR 11-450) pg/ml) and no-VAP (10 (IQR 2.9-105) pg/ml) patients (P = 0.03).

CONCLUSIONS

In COVID-19 ICU patients, differences in microbial sampling at VAP suspicion could lead to high variability in VAP incidence and microbiological findings. Concordance between ETA and BAL was mainly limited by over 20% of ETA positive and BAL negative samples, while BALFAPPP showed high sensitivity but limited specificity when evaluating in-panel targets only. These factors should be considered when comparing results of cohorts with different sampling. BAL IL-1β showed potential in discriminating microbiologically confirmed VAP.

CLINICAL TRIAL REGISTRATION

NCT04766983, registered on February 23, 2021.

iNKT cell-neutrophil crosstalk promotes colorectal cancer pathogenesis

iNKT cells account for a relevant fraction of effector T-cells in the intestine and are considered an attractive platform for cancer immunotherapy. Although iNKT cells are cytotoxic lymphocytes, their functional role in colorectal cancer (CRC) is still controversial, limiting their therapeutic use. Thus, we examined the immune cell composition and iNKT cell phenotype of CRC lesions in patients (n = 118) and different murine models. High-dimensional single-cell flow-cytometry, metagenomics, and RNA sequencing experiments revealed that iNKT cells are enriched in tumor lesions. The tumor-associated pathobiont Fusobacterium nucleatum induces IL-17 and Granulocyte-macrophage colony-stimulating factor (GM-CSF) expression in iNKT cells without affecting their cytotoxic capability but promoting iNKT-mediated recruitment of neutrophils with polymorphonuclear myeloid-derived suppressor cells-like phenotype and functions. The lack of iNKT cells reduced the tumor burden and recruitment of immune suppressive neutrophils. iNKT cells in-vivo activation with α-galactosylceramide restored their anti-tumor function, suggesting that iNKT cells can be modulated to overcome CRC-associated immune evasion. Tumor co-infiltration by iNKT cells and neutrophils correlates with negative clinical outcomes, highlighting the importance of iNKT cells in the pathophysiology of CRC. Our results reveal a functional plasticity of iNKT cells in CRC, suggesting a pivotal role of iNKT cells in shaping the tumor microenvironment, with relevant implications for treatment.

Neonatal alloimmune neutropenia: diagnosis and management of 31 Italian patients

BACKGROUND

In neonates, antibody-mediated destruction of neutrophils may occur as a consequence of auto- or isoimmune disorders. There are few studies on this topic, and particularly on neonatal alloimmune neutropenia (NAN).

MATERIALS AND METHODS

We retrospectively evaluated the clinical and molecular/serological findings of 83 neutropenic infants referred to our Reference Laboratory for diagnostic evaluation of NAN, from 2008 to 2021. We also genotyped 260 Italian healthy subjects for the four principal human neutrophil antigens (HNA).

RESULTS

The diagnosis of NAN was confirmed in 31 cases. The other 52 cases were autoimmune neutropenia (n=21), neutropenia caused by maternal neutrophil autoantibodies (n=8), neutropenia of non-immune origin (n=17), and cases in which a diagnosis could not be reached (n=6). The median age at neutropenia onset and absolute neutrophil count (ANC) were significantly lower in NAN than in non-NAN cases (1 vs 30 days, p<0.005; 330 vs 580/μL, p=0.003, respectively). About 74% of NAN cases developed neutropenia within the first week of life and laboratory investigations were required within 2 weeks. In five patients the neutropenia was discovered at the end of the first month of life and they were referred to our laboratory 1-2 months later when neutropenia had already resolved. Infections were seen in 19% of NAN cases. The median time to resolution of NAN was 31 days. About 50% of NAN cases were due to alloantibodies against HNA-1b, the most frequent allele of HNA-1 in the Italian population (allele frequency 0.63). In five cases of NAN the mothers had an HNA-1 null phenotype, a frequency higher than that observed in our Italian cohort.

DISCUSSION

NAN should be considered by clinicians in infants with neutropenia onset within 5-7 days of life, even though there can be other reasons for a low ANC. If neutropenia is detected later, benign neutropenia seems more likely, although persistence of maternal alloantibodies cannot be ruled out.

Long-term follow-up in common variable immunodeficiency: the pediatric-onset and adult-onset landscape

Introduction

The primary aim of this study is to investigate the evolution of the clinical and laboratory characteristics during the time in a longitudinal cohort of pediatric-onset and adult-onset Common Variable Immunodeficiency (CVID) patients in order to identify early predictive features of the disease and immune dysregulation complications.

Methods

This is a retrospective-prospective monocentric longitudinal study spanning from 1984 to the end of 2021. The data of pediatric-onset vs. adult-onset patients have been compared for immunological features and for infectious and non-infectious complications assessed at diagnosis and follow-up.

Results

Seventy-three CVID patients have been enrolled, with a mean of 10.0 years (SD ± 8.17) of prospective follow-up. At diagnosis, infections were observed in 89.0% of patients and immune dysregulation in 42.5% of patients. At diagnosis, 38.6% of pediatric-onset and 20.7% of adult-onset patients presented with only infections. Polyclonal lymphoid proliferation (62.1%) and autoimmunity (51.7%) were more prevalent in the adult-onset than in the pediatric-onset group (polyclonal lymphoid proliferation 52.3% and autoimmunity 31.8%, respectively). Enteropathy was present in 9.1% of pediatric-onset and 17.2% of adult-onset patients. The prevalence of polyclonal lymphoid proliferation increased during follow-up more in pediatric-onset patients (diagnosis 52.3%-follow-up 72.7%) than in adult-onset patients (diagnosis 62.1%-follow-up 72.7%). The cumulative risk to develop immune dysregulation increases according to the time of disease and the time of diagnostic delay. At the same age, pediatric-onset patients have roughly double the risk of having a complication due to immune dysregulation than adult-onset patients, and it increases with diagnostic delay. The analysis of lymphocyte subsets in the pediatric-onset group showed that CD21 low B cells at diagnosis may be a reliable prognostic marker for the development of immune dysregulation during follow-up, as the ROC curve analysis showed (AUC = 0.796). In the adult-onset group, the percentage of transitional B cells measured at diagnosis showed a significant accuracy (ROC AUC = 0.625) in identifying patients at risk of developing immune dysregulation.

Discussion

The longitudinal evaluation of lymphocyte subsets combined with clinical phenotype can improve the prediction of lymphoid proliferation and allow experts to achieve early detection and better management of such complex disorder.

OP0089 RNAseq PROFILING OF RHEUMATOID ARTHRITIS PATIENTS TO PREDICT RESPONSE TO TOFACITINIB

Background

Rheumatoid arthritis (RA) is characterized by chronic inflammatory synovitis and progressive disability. Nowadays the natural history and the prognosis of the disease has deeply changed thanks to the availability of conventional and targeted disease modifying anti-rheumatic drugs (DMARDs). Nevertheless, clinical response to treatment is highly variable and a considerable proportion of patients do not - or only partially - respond to the treatment. The stratification of patients through the identification of biological predictors of good clinical response to treatment could allow the selection of the best therapeutic strategy for each patient. Recently, precision medicine in rheumatology could rely on the development of new transcriptomics techniques, such as RNA sequencing (RNAseq), that permit to explore complex cellular and molecular networks associated with pathophysiological aspects.

Objectives

To characterize the transcriptomic profiles (RNAseq) of whole-blood samples of moderate to severe RA patients to predict the clinical response to tofacitinib.

Methods

We selected patients with active RA, candidate to receive tofacitinib after failure of a previous therapy with conventional or biologic DMARDs. RNAseq profiling on whole-blood samples (PAX gene tubes) was performed at baseline and after 24 weeks of treatment with tofacitinib. Treatment response was evaluated at week 24 by CDAI EULAR response criteria as drug responder (major or moderate response) or non-responder (minor or no response). Differential expression of gene ontology (GO) biological processes (BP) pathways was analyzed to identify the response-associated pathways. Machine learning models were built by different data mining algorithm to predict response to tofacitinib.

Results

The study population included 33 patients, of whom 7 discontinued prematurely the treatment (5 because of adverse events and 2 because of inefficacy) and 2 were lost to follow-up. At week 24, 10 patients (38.5%) had major, 4 (15.4%) moderate, 6 (23.1%) minor, and 6 (23.1%) no clinical response to tofacitinib. No significant difference was observed between responders and non-responders in terms of baseline characteristics (age, sex, rheumatoid factor and anti–cyclic citrullinated peptide [ACPA] positivity, DMARDs and prednisone exposure, Table 1). Overall, 307 out of 2137 coding transcripts and 85 GO BP pathways were differentially expressed after treatment in responders vs non-responders (Figure 1). In detail, an up-regulation of JAK-dependent pathways, including cation transport, metabolism of membrane lipids, calcium-mediated signaling, and osteoblast proliferation was observed in responders. Conversely, in non-responders, processes related to B cell activation, proliferation, and signaling along with mRNA epigenetic modifications were increased. After extensive internal validation (50 runs of 80:20 hold-out sampling) with univariate selection of GO terms, the accuracy of Support vector Machine (SVM) learning models to predict the correct clinical response was equal to 88.3% (AUROC = 0.940).

Table 1.

Demographic and baseline clinical characteristics of the study population*

Non responders(n = 12)Responders(n = 14)Female, n (%)11 (91.7%)11 (78.6%)Age, years (±SD)52.6±11.254.3±10.5Rheumatoid factor, n (%)7 (58.3%)7 (50%)ACPA, n (%)9 (75%)8 (57.1%)Concomitant csDMARDs, n (%)5 (41.7%)8 (57.1%)bsDMARDs naïve, n (%)12 (100%)11 (78.6%)Prednisone ≥ 5mg/day, n (%)4 (33.3%)6 (42.8%)

* There were no significant differences, determined by Fisher’s exact test for categorical variables

Figure 1.

Heatmap representation of selected GO BP pathways in responders/non-responders.

Conclusion

Machine learning models based on transcriptomic functional pathways can accurately predict response to tofacitinib. Our study could contribute to improve the treatment customization and the optimization of RA treatment strategy toward a personalized approach. Furthermore, these findings may help to understand the mechanisms underlying the clinical response to JAK inhibitors.

Disclosure of Interests

None declared.

Effective high-throughput isolation of enriched platelets and circulating pro-angiogenic cells to accelerate skin-wound healing

Delayed wound healing and chronic skin lesions represent a major health problem. Over the past years, growth factors mediated by platelet-rich plasma (PRP) and cell-based therapies were developed as effective and affordable treatment able to improve wound healing capacity. We have advanced existing concepts to develop a highly efficient high-throughput protocol with proven application for the isolation of PRP and pro-angiogenic cells (Angio^PRP). This protocol outlines the effectiveness of Angio^PRP in promoting the critical healing process including wound closure, re-epithelialization, granulation tissue growth, and blood vessel regeneration. We coupled this effect with normalization of mechanical properties of rescued mouse wounds, which is sustained by a correct arrangement of elastin and collagen fibers. Proteomic analysis of treated wounds demonstrated a fingerprint of Angio^PRP based on the up-regulation of detoxification pathway of glutathione metabolism, correlated to a decrease in inflammatory response. Overall, these results have enabled us to provide a framework for how Angio^PRP supports wound healing, opening avenues for further clinical advances.

IL10 Secretion Endows Intestinal Human iNKT Cells with Regulatory Functions Towards Pathogenic T Lymphocytes

BACKGROUND AND AIMS

Invariant natural killer T [iNKT] cells perform pleiotropic functions in different tissues by secreting a vast array of pro-inflammatory and cytotoxic molecules. However, the presence and function of human intestinal iNKT cells capable of secreting immunomodulatory molecules such as IL-10 has never been reported so far. Here we describe for the first time the presence of IL10-producing iNKT cells [NKT10 cells] in the intestinal lamina propria of healthy individuals and of Crohn's disease [CD] patients.

METHODS

Frequency and phenotype of NKT10 cells were analysed ex vivo from intestinal specimens of Crohn's disease [n = 17] and controls [n = 7]. Stable CD-derived intestinal NKT10 cell lines were used to perform in vitro suppression assays and co-cultures with patient-derived mucosa-associated microbiota. Experimental colitis models were performed by adoptive cell transfer of splenic naïve CD4+ T cells in the presence or absence of IL10-sufficient or -deficient iNKT cells. In vivo induction of NKT10 cells was performed by administration of short chain fatty acids [SCFA] by oral gavage.

RESULTS

Patient-derived intestinal NKT10 cells demonstrated suppressive capabilities towards pathogenic CD4+ T cells. The presence of increased proportions of mucosal NKT10 cells associated with better clinical outcomes in CD patients. Moreover, an intestinal microbial community enriched in SCFA-producing bacteria sustained the production of IL10 by iNKT cells. Finally, IL10-deficient iNKT cells failed to control the pathogenic activity of adoptively transferred CD4+ T cells in an experimental colitis model.

CONCLUSIONS

These results describe an unprecedentd IL10-mediated immunoregulatory role of intestinal iNKT cells in controlling the pathogenic functions of mucosal T helper subsets and in maintaining the intestinal immune homeostasis.

Safety and effectiveness of up to 3 years' bulevirtide monotherapy in patients with HDV-related cirrhosis

The entry inhibitor bulevirtide (BLV) received conditional approval from the EMA in July 2020 for the treatment of adult patients with compensated chronic hepatitis delta. However, the effectiveness and safety of BLV administered as monotherapy beyond 48 weeks in difficult-to-treat patients with HDV-related cirrhosis is presently unknown. Herein, we describe the first patients with HDV-related compensated cirrhosis who were treated with BLV (10 mg/day as a starting dose) for up to 3 years on a compassionate use program. Patients were also monitored for HBcrAg and HBV RNA levels, and HDV- and HBV-specific T-cell markers. In the patient who stopped BLV at week 48, after achieving a virological and biochemical response, the initial virological and biochemical rebound was followed by alanine aminotransferase normalization coupled with low HDV RNA and HBsAg levels. In the 2 patients treated continuously for 3 years, virological and biochemical responses were maintained throughout the treatment period even after dose reduction. In a patient with advanced compensated cirrhosis, liver function tests significantly improved, esophageal varices disappeared, and histological/laboratory features of autoimmune hepatitis resolved. Overall, no safety issues were recorded, as bile salt increase was asymptomatic. While serum HBV RNA levels remained undetectable in all patients, HBV core-related antigen levels showed a progressive, yet modest decline during long-term BLV treatment. No HDV-specific interferon-γ-producing T cells were detected, neither after HDV reactivation (after BLV withdrawn in Patient 1) nor during 3 years of BLV treatment. In conclusion, this report shows that continuous administration of BLV monotherapy for 3 years leads to excellent virological and clinical responses in patients with HDV-related cirrhosis who had contraindications to interferon-based therapies.

Integrative Analysis Reveals a Molecular Stratification of Systemic Autoimmune Diseases

OBJECTIVE

Clinical heterogeneity, a hallmark of systemic autoimmune diseases, impedes early diagnosis and effective treatment, issues that may be addressed if patients could be classified into groups defined by molecular pattern. This study was undertaken to identify molecular clusters for reclassifying systemic autoimmune diseases independently of clinical diagnosis.

METHODS

Unsupervised clustering of integrated whole blood transcriptome and methylome cross-sectional data on 955 patients with 7 systemic autoimmune diseases and 267 healthy controls was undertaken. In addition, an inception cohort was prospectively followed up for 6 or 14 months to validate the results and analyze whether or not cluster assignment changed over time.

RESULTS

Four clusters were identified and validated. Three were pathologic, representing "inflammatory," "lymphoid," and "interferon" patterns. Each included all diagnoses and was defined by genetic, clinical, serologic, and cellular features. A fourth cluster with no specific molecular pattern was associated with low disease activity and included healthy controls. A longitudinal and independent inception cohort showed a relapse-remission pattern, where patients remained in their pathologic cluster, moving only to the healthy one, thus showing that the molecular clusters remained stable over time and that single pathogenic molecular signatures characterized each individual patient.

CONCLUSION

Patients with systemic autoimmune diseases can be jointly stratified into 3 stable disease clusters with specific molecular patterns differentiating different molecular disease mechanisms. These results have important implications for future clinical trials and the study of nonresponse to therapy, marking a paradigm shift in our view of systemic autoimmune diseases.

Functionalized Scintillating Nanotubes for Simultaneous Radio- and Photodynamic Therapy of Cancer

As a model radio-photodynamic therapy (RPDT) agent, we developed a multicomponent nanomaterial by anchoring conjugated chromophores on the surface of scintillating chrysotile nanotubes. Its ultimate composition makes the system a scintillation-activated photosensitizer for the singlet oxygen production. This nanomaterial shows a remarkable ability to enhance the production of singlet oxygen in an aqueous environment, under X-ray irradiation, boosting its production by almost 1 order of magnitude. Its efficiency as a coadjutant for radiotherapy has been tested in vitro, showing a striking efficacy in enhancing both the prompt cytotoxicity of the ionizing radiation and the long-term cytotoxicity given by radiation-activated apoptosis. Notably, the beneficial activity of the RPDT agent is prominent at low levels of delivered doses comparable to the one employed in clinical treatments. This opens the possibility of effectively reducing the therapy exposure and consequently undesired collateral effects due to prolonged exposure of patients to high-energy radiation.

Impact of SARS-CoV-2 infection on the recovery of peripheral blood mononuclear cells by density gradient

SARS-CoV-2 virus infection is responsible for coronavirus disease (COVID-19), which is characterised by a hyperinflammatory response that plays a major role in determining the respiratory and immune-mediated complications of this condition. While isolating peripheral blood mononuclear cells (PBMCs) from whole blood of COVID-19 patients by density gradient centrifugation, we noticed some changes in the floating properties and in the sedimentation of the cells on density medium. Investigating this further, we found that in early phase COVID-19 patients, characterised by reduced circulating lymphocytes and monocytes, the PBMC fraction contained surprisingly high levels of neutrophils. Furthermore, the neutrophil population exhibited alterations in the cell size and in the internal complexity, consistent with the presence of low density neutrophils (LDNs) and immature forms, which may explain the shift seen in the floating abilities and that may be predictive of the severity of the disease. The percentage of this subset of neutrophils found in the PBMC band was rather spread (35.4 ± 27.2%, with a median 28.8% and IQR 11.6-56.1, Welch's t-test early phase COVID-19 versus blood donor healthy controls P < 0.0001). Results confirm the presence of an increased number of LDNs in patients with early stage COVID-19, which correlates with disease severity and may be recovered by centrifugation on a density gradient together with PBMCs.

Early Phases of COVID-19 Are Characterized by a Reduction in Lymphocyte Populations and the Presence of Atypical Monocytes

Background

Severe acute respiratory syndrome coronavirus 2 is a recently discovered pathogen responsible of coronavirus disease 2019 (COVID-19). The immunological changes associated with this infection are largely unknown.

Methods

We evaluated the peripheral blood mononuclear cells profile of 63 patients with COVID-19 at diagnosis. We also assessed the presence of association with inflammatory biomarkers and the 28-day mortality.

Results

Lymphocytopenia was present in 51 of 63 (80.9%) patients, with a median value of 720 lymphocytes/µl (IQR 520-1,135). This reduction was mirrored also on CD8+ (128 cells/µl, IQR 55-215), natural killer (67 cells/µl, IQR 35-158) and natural killer T (31 cells/µl, IQR 11-78) cells. Monocytes were preserved in total number but displayed among them a subpopulation with a higher forward and side scatter properties, composed mainly of cells with a reduced expression of both CD14 and HLA-DR. Patients who died in the 28 days from admission (N=10, 15.9%), when compared to those who did not, displayed lower mean values of CD3+ (337.4 cells/µl vs 585.9 cells/µl; p=0.028) and CD4+ cells (232.2 cells/µl vs 381.1 cells/µl; p=0.042) and an higher percentage of CD8+/CD38+/HLA-DR+ lymphocytes (13.5% vs 7.6%; p=0.026).

Discussion

The early phases of COVID-19 are characterized by lymphocytopenia, predominance of Th2-like lymphocytes and monocytes with altered immune profile, which include atypical mononuclear cells.

Excellent safety and effectiveness of high-dose myrcludex-B monotherapy administered for 48 weeks in HDV-related compensated cirrhosis: A case report of 3 patients

Short-term administration of the entry inhibitor myrcludex-B (MyrB) has been shown to be safe and effective in phase II studies in patients coinfected with hepatitis B virus (HBV) and hepatitis delta virus (HDV). However, its effectiveness and safety are unknown during long-term and high-dose treatment of patients with compensated cirrhosis in real-life settings. Herein, we describe the first 3 European patients with HDV-related compensated cirrhosis who were treated with MyrB 10 mg/day for 48 weeks as a compassionate therapy. Liver function tests, bile acids, and virological markers were monitored every 4 weeks. HBV/HDV-specific T cell quantity (up to 48 and 36 weeks) and HBV RNA levels were also assessed in 2 cases. During MyrB treatment, HDV RNA levels progressively declined from 4.4 and 5.6 logs IU/ml to undetectability in 2 cases, and from 6.8 log copies/ml to 500 copies/ml for the other patient. Alanine aminotransferase normalised after 20, 12 and 28 weeks, respectively. A significant improvement in features of portal hypertension, liver function tests and alpha-fetoprotein levels were documented in 2 cases. In the male patient with histological and clinical stigmata of autoimmune hepatitis, IgG and immunoglobulins rapidly normalised. No significant changes in HBV surface antigen levels and circulating HBV/HDV-specific T cells were demonstrated; HBV DNA and HBV RNA levels remained undetectable throughout the study period. MyrB was well tolerated; patients remained fully asymptomatic despite a significant increase of bile acids. In conclusion, this report shows excellent safety and effectiveness of a 48-week course of MyrB 10 mg/day, combined with tenofovir disoproxil fumarate, for the treatment of HDV-related compensated cirrhosis.

Mucosa-associated microbiota drives pathogenic functions in IBD-derived intestinal iNKT cells

Inflammatory bowel disease (IBD) pathogenesis has been linked to the aberrant activation of the Gut-associated lymphoid tissues against components of the intestinal microbiota. Although the contribution of CD4⁺ T helper cells to inflammatory processes is being increasingly acknowledged, the functional engagement of human invariant natural killer T (iNKT) cells is still poorly defined. Here, we evaluated the functional characteristics of intestinal iNKT cells during IBD pathogenesis and to exploit the role of mucosa-associated microbiota recognition in triggering iNKT cells' pro-inflammatory responses in vivo. Lamina propria iNKT cells, isolated from surgical specimens of active ulcerative colitis and Crohn's disease patients and non-IBD donors, were phenotypically and functionally analyzed ex vivo, and stable cell lines and clones were generated for in vitro functional assays. iNKT cells expressing a pro-inflammatory cytokine profile were enriched in the lamina propria of IBD patients, and their exposure to the mucosa-associated microbiota drives pro-inflammatory activation, inducing direct pathogenic activities against the epithelial barrier integrity. These observations suggest that iNKT cell pro-inflammatory functions may contribute to the fuelling of intestinal inflammation in IBD patients.

Histone modifications underlie monocyte dysregulation in patients with systemic sclerosis, underlining the treatment potential of epigenetic targeting

BACKGROUND AND OBJECTIVE

Systemic sclerosis (SSc) is a severe autoimmune disease, in which the pathogenesis is dependent on both genetic and epigenetic factors. Altered gene expression in SSc monocytes, particularly of interferon (IFN)-responsive genes, suggests their involvement in SSc development. We investigated the correlation between epigenetic histone marks and gene expression in SSc monocytes.

METHODS

Chromatin immunoprecipitation followed by sequencing (ChIPseq) for histone marks H3K4me3 and H3K27ac was performed on monocytes of nine healthy controls and 14 patients with SSc. RNA sequencing was performed in parallel to identify aberrantly expressed genes and their correlation with the levels of H3K4me3 and H3K27ac located nearby their transcription start sites. ChIP-qPCR assays were used to verify the role of bromodomain proteins, H3K27ac and STATs on IFN-responsive gene expression.

RESULTS

1046 and 534 genomic loci showed aberrant H3K4me3 and H3K27ac marks, respectively, in SSc monocytes. The expression of 381 genes was directly and significantly proportional to the levels of such chromatin marks present near their transcription start site. Genes correlated to altered histone marks were enriched for immune, IFN and antiviral pathways and presented with recurrent binding sites for IRF and STAT transcription factors at their promoters. IFNα induced the binding of STAT1 and STAT2 at the promoter of two of these genes, while blocking acetylation readers using the bromodomain BET family inhibitor JQ1 suppressed their expression.

CONCLUSION

SSc monocytes have altered chromatin marks correlating with their IFN signature. Enzymes modulating these reversible marks may provide interesting therapeutic targets to restore monocyte homeostasis to treat or even prevent SSc.

Pathogenicity of In Vivo Generated Intestinal Th17 Lymphocytes is IFNγ Dependent

BACKGROUND AND AIMS

T helper 17 [Th17] cells are crucially involved in the immunopathogenesis of inflammatory bowel diseases in humans. Nevertheless, pharmacological blockade of interleukin 17A [IL17A], the Th17 signature cytokine, yielded negative results in patients with Crohn's disease [CD], and attempts to elucidate the determinants of Th17 cells' pathogenicity in the gut have so far proved unsuccessful. Here, we aimed to identify and functionally validate the pathogenic determinants of intestinal IL-17-producing T cells.

METHODS

In vivo-generated murine intestinal IL-17-producing T cells were adoptively transferred into immunodeficient Rag1-/- recipients to test their pathogenicity. Human IL-17, IFNγ/IL-17, and IFNγ actively secreting T cell clones were generated from lamina propria lymphocytes of CD patients. The pathogenic activity of intestinal IL-17-producing T cells against the intestinal epithelium was evaluated.

RESULTS

IL-17-producing cells with variable colitogenic activity can be generated in vivo using different experimental colitis models. The pathogenicity of IL-17-secreting cells was directly dependent on their IFNγ secretion capacity, as demonstrated by the reduced colitogenic activity of IL-17-secreting cells isolated from IFNγ-/- mice. Moreover, IFNγ production is a distinguished attribute of CD-derived lamina propria Th17 cells. IFNγ secretion by CD-derived IL-17-producing intestinal clones is directly implicated in the epithelial barrier disruption through the modulation of tight junction proteins.

CONCLUSIONS

Intestinal Th17 cell pathogenicity is associated with IFNγ production, which directly affects intestinal permeability through the disruption of epithelial tight junctions.

Angiogenesis in human brain tumors: screening of drug response through a patient-specific cell platform for personalized therapy

Gliomas are the most common brain tumors, with diverse biological behaviour. Glioblastoma (GBM), the most aggressive and with the worst prognosis, is characterized by an intense and aberrant angiogenesis, which distinguishes it from low-grade gliomas (LGGs) and benign expansive lesions, as meningiomas (MNGs). With increasing evidence for the importance of vascularization in tumor biology, we focused on the isolation and characterization of endothelial cells (ECs) from primary GBMs, LGGs and MNGs. Gene expression analysis by Real-Time PCR, immunofluorescence and flow cytometry analysis, tube-like structures formation and vascular permeability assays were performed. Our results showed a higher efficiency of ECs to form a complex vascular architecture, as well as a greater impairment of a brain blood barrier model, and an overexpression of pro-angiogenic mediators in GBM than in LGG and MNG. Furthermore, administration of temozolomide, bevacizumab, and sunitinib triggered a different proliferative, apoptotic and angiogenic response, in a dose and time-dependent manner. An increased resistance to temozolomide was observed in T98G cells co-cultured in GBM-EC conditioned media. Therefore, we developed a novel platform to reproduce tumor vascularization as “disease in a dish”, which allows us to perform screening of sensitivity/resistance to drugs, in order to optimize targeted approaches to GBM therapy.

Expression of C19MC miRNAs in HCC associates with stem-cell features and the cancer-testis genes signature

BACKGROUND

Intratumor heterogeneity of hepatocellular carcinoma (HCC) and, among HCC cell subsets, the cancer stem cell population (hCSC), is responsible for therapeutic resistance and disease relapse.

AIMS

To characterize hCSC-enriched HCCs at the molecular level.

METHODS

Side population (SP) was used to identify the hCSCs in multiple tumor sampling from different patients and primary HCCs cultures. FACS was used to immunoprofile cultures. miRNAs were profiled in samples and correlated to SP. The Cancer Genome Atlas (TCGA) HCC dataset was analyzed to search for signatures associated with C19MC miRNAs expression. Results were confirmed by immunohistochemistry.

RESULTS

The miRNA cluster on chromosome 19 (C19MC) was enriched in SP and in HCCs with a high SP fraction. At the molecular level, an elevated C19MC was correlated with expression of precursor transcripts. In TCGA-HCC series, high C19MC expression identified a subset of patients with poorer prognosis, advanced disease and overexpression of the cancer-testis (CT) antigens. These data were confirmed in an independent cohort of HCCs and at the protein level.

CONCLUSION

C19MC miRNAs and CT antigens overexpression represents a novel oncogenic pathway in a subset of hCSC-enriched HCCs with dismal prognosis. CT antigens are promising immunotherapy targets. Therefore, these molecular signatures could identify HCCs who could benefit from immunotherapy.

FGF23 and Fetuin-A Interaction in the Liver and in the Circulation

Recently it has been demonstrated that Fetuin-A, an anti-inflammatory protein synthesized by the liver, is produced also in bone by an FGF23-regulated pathway. FGF23 has been also demonstrated to induce inflammatory cytokine production in the liver. This study aimed to explore if FGF23 plays a role in the Fetuin-A production in the liver cells too and the possible relationships with FGF23 pro-inflammatory effects.

FGF23 and Fetuin-A were studied in liver, kidney and in plasma with immunochemistry, immunoprecipitation, western blot, chromatin immunoprecipitation, duolink, ELISA, qrtPCR methodology.

FGF23 is produced, but not secreted by the liver cells. In hepatocytes and circulation, FGF23 was present only strictly linked to Fetuin-A, while Fetuin-A was found also in unbounded form. No link was observed in the kidney. FGF23 up to 600 pg/ml stimulates, while, at higher concentrations, reduces Fetuin-A expression. Notably, overall the range of concentrations, FGF23 stimulates Fetuin-A promoter, TNFα and IL6 expression. In the nucleus, FGF23 seems to act as a direct transcription factor of Fetuin-A promoter.

These results suggest that FGF23 played a direct regulatory role in Fetuin-A expression in liver cells with a biphasic effect: Fetuin-A progressively increases when FGF23 increases up to 400-600 pg/mL, and declines at higher FGF23 concentrations. These results lead us to hypothesize: a) a possible epigenetic post-transcriptional regulation; b) a possible counter-regulatory effect of FGF23 induced inflammatory cytokines (TNFα/ NF-κB mechanism). This study could add an additional key for the interpretation of the possible mechanisms linking FGF23, Fetuin-A and inflammation in CKD patients and suggests a role for FGF23 as transcription factor.

Diagnostic value of cell bound and circulating neutrophil antibody detection in pediatric neutropenia

BACKGROUND

Chronic benign neutropenia of infancy includes primary autoimmune neutropenia (pAIN) and chronic idiopathic neutropenia (CIN). A diagnosis of CIN is supported by the absence of free and/or cell-bound neutrophil autoantibodies, which can be detected by flow cytometry with the indirect-granulocyte immunofluorescence test (I-GIFT) and direct-granulocyte immunofluorescence test (D-GIFT), respectively. Conclusive evidence is lacking on the diagnostic value of the D-GIFT, whose performance requires specific laboratory expertise, may be logistically difficult, and hampered by very low neutrophil count in patient samples. This study investigated whether the evaluation of D-GIFT improves the diagnostic accuracy of pediatric neutropenia.

PROCEDURE

I-GIFT and D-GIFT were performed in 174 pAIN, 162 CIN, 81 secondary AIN, 51 postinfection neutropenic, and 65 nonautoimmune neutropenic children referred to this laboratory during 2002-2014.

RESULTS

Using 90% specific median fluorescence intensity cut-off values calculated by receiver operating characteristic curves, D-GIFT was positive in 49% of CIN patients, who showed similar clinical features as those with pAIN. In 44 (27%) of 162 CIN patients, I-GIFT was repeated two to three times in a year, resulting positive in 12 and two patients at second and third screening, respectively. Interestingly, 10 of the latter 14 patients showed a positive D-GIFT at the first serological screening. False positive D-GIFT was shown by 12% and 22% of nonneutropenic and nonautoimmune neutropenic patients, respectively.

CONCLUSIONS

D-GIFT evaluation improves the diagnostic accuracy of pediatric neutropenia, but improvement of cell-bound antibody detection is needed to decrease false positive results.

The epigenetically regulated miR-494 associates with stem-cell phenotype and induces sorafenib resistance in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents the second cause of cancer-related mortality worldwide and is associated with poor prognosis, especially in patients not amenable for curative treatments. The multi-kinase inhibitor sorafenib represents the first-line treatment option for advanced HCC; nevertheless, its effectiveness is limited due to tumor heterogeneity as well as innate or acquired drug resistance, raising the need for new therapeutic strategies. MicroRNAs (miRNAs) involvement in treatment response as well as their safety and efficacy in preclinical models and clinical trials have been widely documented in the oncologic field, including HCC. Here, we identified miR-494 upregulation in a subgroup of human and rat HCCs with stem cell-like characteristics, as well as multiple epigenetic mechanisms involved in its aberrant expression in HCC cell lines and patients. Moreover, we identified p27, puma and pten among miR-494 targets, contributing to speed up cell cycle progression, enhance survival potential in stressful conditions and increase invasive and clonogenic capabilities. MiR-494 overexpression increased sorafenib resistance via mTOR pathway activation in HCC cell lines and, in line, high miR-494 levels associated with decreased sorafenib response in two HCC animal models. A sorafenib-combined anti-miR-494-based strategy revealed an enhanced anti-tumor potential with respect to sorafenib-only treatment in our HCC rat model. In conclusion, our findings suggested miR-494 as a possible therapeutic target as well as a candidate biomarker for patient stratification in advanced HCC.

Spontaneous intracerebral hemorrhage as presentation of atypical central neurocytoma: the role of angiogenesis through the characterization of tumor endothelial cells

A 36-year-old white man presented with sudden-onset headache and rapid deterioration of consciousness. Computer tomography revealed a right capsular intra-parenchimal hemorrhage with an intraventricular component; therefore, emergency surgery was performed. Once the hematoma was evacuated, the cause of the hemorrhage was identified as a tumor mass and it was resected. Histopathological and immunohistochemical examinations of the surgical specimen disclosed a diagnosis of atypical central neurocytoma. By using a protocol recently set up in our laboratory, we succeeded in isolating and propagating, for the first time, human endothelial cells from central neurocytoma (CN-ECs). Different analyses revealed that isolated CN-ECs consist of a pure endothelial cell population, with the expression of endothelial markers (CD31, CD309/VEGFR2, CD105, eNOS) and with angiogenic properties, such as the uptake of LDL. Moreover, CN-ECs spontaneously organize in a vascular-like structure. The goal of this case report is to stress the need for further studies focused on understanding the causes of the onset of an intra-parenchimal hemorrhage in the presence of an atypical central neurocytoma in order to tailor treatments to each single patient and achieve the best clinical outcome.

iPSC-derived LewisX+CXCR4+β1-integrin+ neural stem cells improve the amyotrophic lateral sclerosis phenotype by preserving motor neurons and muscle innervation in human and rodent models

Amyotrophic lateral sclerosis (ALS) is a fatal incurable neurodegenerative disease characterized by progressive degeneration of motor neurons (MNs), leading to relentless muscle paralysis. In the early stage of the disease, MN loss and consequent muscle denervation are compensated by axonal sprouting and reinnervation by the remaining MNs, but this mechanism is insufficient in the long term. Here, we demonstrate that induced pluripotent stem cell-derived neural stem cells (NSCs), in particular the subpopulation positive for LewisX-CXCR4-β1-integrin, enhance neuronal survival and axonal growth of human ALS-derived MNs co-cultured with toxic ALS astrocytes, acting on both autonomous and non-autonomous ALS disease features. Transplantation of this NSC fraction into transgenic SOD1G93A ALS mice protects MNs in vivo, promoting their ability to maintain neuromuscular junction integrity, inducing novel axonal sprouting and reducing macro- and microgliosis. These effects result in a significant increase in survival and an improved neuromuscular phenotype in transplanted SOD1G93A mice. Our findings suggest that effective protection of MN functional innervation can be achieved by modulation of multiple dysregulated cellular and molecular pathways in both MNs and glial cells. These pathways must be considered in designing therapeutic strategies for ALS patients.

B Cell Activating Factor (BAFF) and BAFF Receptor Expression in Autoimmune and Nonautoimmune Thyroid Diseases

BACKGROUND

The B cell activating factor (BAFF) is a member of the tumor necrosis factor family, which controls the survival/proliferation of B cells and is involved in the pathogenesis of a number of autoimmune diseases. The objective of the present study was to investigate the expression of BAFF and BAFF receptor (BAFF-R) in the thyroid tissue of patients affected with autoimmune thyroid disorders (AITD) or multinodular goiter (MNG) compared with those with normal thyroids.

METHODS

Immunohistochemistry was performed using a panel of antibodies against BAFF, BAFF-R, CD3, CD4, CD8, CD20, CD34, CD79a, CD1a, CD68, and CD163 on the thyroid sections of 27 patients affected with Graves' disease (GD), 23 with Hashimoto's thyroiditis (HT), 16 with nontoxic nodular goiter (NTG), and 15 with toxic nodular goiter (TG), submitted to total thyroidectomy between 2000 and 2011.

RESULTS

The overall BAFF-R expression in thyrocytes was weak and not different in AITD and MNG. Conversely, a stronger BAFF expression was observed in MNG compared with AITD. BAFF and BAFF-R expression in the infiltrating lymphocytes was higher in AITD compared with MNG. Interestingly, in lymphocytes of follicular-like structures observed in HT, BAFF and BAFF-R were localized in the germinal center or in the mantle, respectively.

CONCLUSIONS

This study shows that BAFF and BAFF-R are expressed in the thyrocytes derived from patients with either AITD or MNG, in addition to the expected expression of BAFF and its receptor in the infiltrating immune cells of GD and HT. These findings suggest a possible involvement of BAFF and its receptors in the pathophysiology of AITD.

Giant Lysosomes as a Chemotherapy Resistance Mechanism in Hepatocellular Carcinoma Cells

Despite continuous improvements in therapeutic protocols, cancer-related mortality is still one of the main problems facing public health. The main cause of treatment failure is multi-drug resistance (MDR: simultaneous insensitivity to different anti-cancer agents), the underlying molecular and biological mechanisms of which include the activity of ATP binding cassette (ABC) proteins and drug compartmentalisation in cell organelles. We investigated the expression of the main ABC proteins and the role of cytoplasmic vacuoles in the MDR of six hepatocellular carcinoma (HCC) cell lines, and confirmed the accumulation of the yellow anti-cancer drug sunitinib in giant (four lines) and small cytoplasmic vacuoles of lysosomal origin (two lines). ABC expression analyses showed that the main ABC protein harboured by all of the cell lines was PGP, whose expression was not limited to the cell membrane but was also found on lysosomes. MTT assays showed that the cell lines with giant lysosomes were more resistant to sorafenib treatment than those with small lysosomes (p<0.01), and that verapamil incubation can revert this resistance, especially if it is administered after drug pre-incubation. The findings of this study demonstrate the involvement of PGP-positive lysosomes in drug sequestration and MDR in HCC cell lines. The possibility of modulating this mechanism using PGP inhibitors could lead to the development of new targeted strategies to enhance HCC treatment.

Modulation of gamma globin genes expression by histone deacetylase inhibitors: an in vitro study

Induction of fetal haemoglobin (HbF) is a promising therapeutic approach for the treatment of β-thalassaemia and sickle cell disease (SCD). Several pharmacological agents, such as hydroxycarbamide (HC) and butyrates, have been shown to induce the γ-globin genes (HBG1, HBG2). However, their therapeutic use is limited due to weak efficacy and an inhibitory effect on erythroid differentiation. Thus, more effective agents are needed. The histone deacetylase (HDAC) inhibitors are potential therapeutic haemoglobin (Hb) inducers able to modulate gene expression through pleiotropic mechanisms. We investigated the effects of a HDAC inhibitor, Givinostat (GVS), on erythropoiesis and haemoglobin synthesis and compared it with sodium butyrate and HC. We used an in vitro erythropoiesis model derived from peripheral CD34⁺ cells of healthy volunteers and SCD donors. GVS effects on erythroid proliferation and differentiation and on Hb synthesis were investigated. We found that GVS at high concentrations delayed erythroid differentiation with no specific effect on HBG1/2 transcription. At a low concentration (1 nmol/l), GVS induced Hb production with no effects on cells proliferation and differentiation. The efficacy of GVS 1 mol/l in Hb induction in vitro was comparable to that of HC and butyrate. Our results support the evaluation of GVS as a new candidate molecule for the treatment of the haemoglobinophathies due to its positive effects on haemoglobin production at low and non-toxic concentrations.