Scientific Resources

The hexamethylene bisacetamide (HMBA) anticancer drug was dismissed due to limited efficacy in leukemic patients but it may re-enter into the clinics in HIV-1 eradication strategies because of its recently disclosed capacity to reactivate latent virus. Here,we investigated the impact of HMBA on the cytotoxicity of natural killer (NK) cells against acute T lymphoblastic leukemia (T-ALL) cells or HIV-1-infected T cells that exit from latency. We show that in T-ALL cells HMBA upmodulated MICB and ULBP2 ligands for the NKG2D activating receptor. In a primary CD4+ T cell-based latency model,HMBA did not reactivate HIV-1,yet enhanced ULBP2 expression on cells harboring virus reactivated by prostratin (PRO). However,HMBA reduced the expression of NKG2D and its DAP10 adaptor in NK cells,hence impairing NKG2D-mediated cytotoxicity and DAP10-dependent response to IL-15 stimulation. Alongside,HMBA dampened killing of T-ALL targets by IL-15-activated NK cells and impaired NK cell-mediated clearance of PRO-reactivated HIV-1+ cells. Overall,our results demonstrate a dominant detrimental effect of HMBA on the NKG2D pathway that crucially controls NK cell-mediated killing of tumors and virus-infected cells,providing one possible explanation for poor clinical outcome in HMBA-treated cancer patients and raising concerns for future therapeutic application of this drug. View Publication

Human immunodeficiency virus type 1 (HIV-1) eradication is prevented by the establishment on infection of cellular HIV-1 reservoirs that are not fully characterized,especially in genital mucosal tissues (the main HIV-1 entry portal on sexual transmission). Here,we show,using penile tissues from HIV-1-infected individuals under suppressive combination antiretroviral therapy,that urethral macrophages contain integrated HIV-1 DNA,RNA,proteins and intact virions in virus-containing compartment-like structures,whereas viral components remain undetectable in urethral T cells. Moreover,urethral cells specifically release replication-competent infectious HIV-1 following reactivation with the macrophage activator lipopolysaccharide,while the T-cell activator phytohaemagglutinin is ineffective. HIV-1 urethral reservoirs localize preferentially in a subset of polarized macrophages that highly expresses the interleukin-1 receptor,CD206 and interleukin-4 receptor,but not CD163. To our knowledge,these results are the first evidence that human urethral tissue macrophages constitute a principal HIV-1 reservoir. Such findings are determinant for therapeutic strategies aimed at HIV-1 eradication. View Publication

HIV persists in latently infected CD4+ T cells during antiretroviral therapy (ART). Immune checkpoint molecules,including PD-1,are preferentially expressed at the surface of persistently infected cells. However,whether PD-1 plays a functional role in HIV latency and reservoir persistence remains unknown. Using CD4+ T cells from HIV-infected individuals,we show that the engagement of PD-1 inhibits viral production at the transcriptional level and abrogates T-cell receptor (TCR)-induced HIV reactivation in latently infected cells. Conversely,PD-1 blockade with the monoclonal antibody pembrolizumab enhances HIV production in combination with the latency reversing agent bryostatin without increasing T cell activation. Our results suggest that the administration of immune checkpoint blockers to HIV-infected individuals on ART may facilitate latency disruption. View Publication

In life sciences,the material properties of suspended cells have attained significance close to that of fluorescent markers but with the advantage of label-free and unbiased sample characterization. Until recently,cell rheological measurements were either limited by acquisition throughput,excessive post processing,or low-throughput real-time analysis. Real-time deformability cytometry expanded the application of mechanical cell assays to fast on-the-fly phenotyping of large sample sizes,but has been restricted to single material parameters as the Young's modulus. Here,we introduce dynamic real-time deformability cytometry for comprehensive cell rheological measurements at up to 100 cells per second. Utilizing Fourier decomposition,our microfluidic method is able to disentangle cell response to complex hydrodynamic stress distributions and to determine viscoelastic parameters independent of cell shape. We demonstrate the application of our technology for peripheral blood cells in whole blood samples including the discrimination of B- and CD4+ T-lymphocytes by cell rheological properties. View Publication

BACKGROUND AIMS Inactivating mutations in MYO5B cause microvillus inclusion disease (MVID),but the physiological cause of the diarrhea associated with this disease is unclear. We investigated whether loss of MYO5B results in aberrant expression of apical enterocyte transporters. METHODS We studied alterations in apical membrane transporters in MYO5B-knockout mice,as well as mice with tamoxifen-inducible,intestine-specific disruption of Myo5b (VilCreERT2;Myo5bflox/flox mice) or those not given tamoxifen (controls). Intestinal tissues were collected from mice and analyzed by immunostaining,immunoelectron microscopy,or cultured enteroids were derived. Functions of brush border transporters in intestinal mucosa were measured in Ussing chambers. We obtained duodenal biopsy specimens from individuals with MVID and individuals without MVID (controls) and compared transporter distribution by immunocytochemistry. RESULTS Compared to intestinal tissues from littermate controls,intestinal tissues from MYO5B-knockout mice had decreased apical localization of SLC9A3 (also called NHE3),SLC5A1 (also called SGLT1),aquaporin (AQP) 7,and sucrase isomaltase,and subapical localization of intestinal alkaline phosphatase and CDC42. However,CFTR was present on apical membranes of enterocytes from MYO5B knockout and control mice. Intestinal biopsies from patients with MVID had subapical localization of NHE3,SGLT1,and AQP7,but maintained apical CFTR. After tamoxifen administration,VilCreERT2;Myo5bflox/flox mice lost apical NHE3,SGLT1,DRA,and AQP7,similar to germline MYO5B knockout mice. Intestinal tissues from VilCreERT2;Myo5bflox/flox mice had increased CFTR in crypts and CFTR localized to the apical membranes of enterocytes. Intestinal mucosa from VilCreERT2;Myo5bflox/flox mice given tamoxifen did not have an intestinal barrier defect,based on Ussing chamber analysis,but did have decreased SGLT1 activity and increased CFTR activity. CONCLUSIONS Although trafficking of many apical transporters is regulated by MYO5B,trafficking of CFTR is largely independent of MYO5B. Decreased apical localization of NHE3,SGLT1,DRA,and AQP7 might be responsible for dysfunctional water absorption in enterocytes of patients with MVID. Maintenance of apical CFTR might exacerbate water loss by active secretion of chloride into the intestinal lumen. View Publication

Gastrointestinal (GI) parasites,hookworms in particular,have evolved to cause minimal harm to their hosts,allowing them to establish chronic infections. This is mediated by creating an immunoregulatory environment. Indeed,hookworms are such potent suppressors of inflammation that they have been used in clinical trials to treat inflammatory bowel diseases (IBD) and celiac disease. Since the recent description of helminths (worms) secreting extracellular vesicles (EVs),exosome-like EVs from different helminths have been characterized and their salient roles in parasite-host interactions have been highlighted. Here,we analyze EVs from the rodent parasite Nippostrongylus brasiliensis,which has been used as a model for human hookworm infection. N. brasiliensis EVs (Nb-EVs) are actively internalized by mouse gut organoids,indicating a role in driving parasitism. We used proteomics and RNA-Seq to profile the molecular composition of Nb-EVs. We identified 81 proteins,including proteins frequently present in exosomes (like tetraspanin,enolase,14-3-3 protein,and heat shock proteins),and 27 sperm-coating protein-like extracellular proteins. RNA-Seq analysis revealed 52 miRNA species,many of which putatively map to mouse genes involved in regulation of inflammation. To determine whether GI nematode EVs had immunomodulatory properties,we assessed their potential to suppress GI inflammation in a mouse model of inducible chemical colitis. EVs from N. brasiliensis but not those from the whipworm Trichuris muris or control vesicles from grapes protected against colitic inflammation in the gut of mice that received a single intraperitoneal injection of EVs. Key cytokines associated with colitic pathology (IL-6,IL-1$\beta$,IFN$\gamma$,and IL-17a) were significantly suppressed in colon tissues from EV-treated mice. By contrast,high levels of the anti-inflammatory cytokine IL-10 were detected in Nb-EV-treated mice. Proteins and miRNAs contained within helminth EVs hold great potential application in development of drugs to treat helminth infections as well as chronic non-infectious diseases resulting from a dysregulated immune system,such as IBD. View Publication

BACKGROUND AIMS The enzyme stearoyl-coenzyme A desaturase 1 (SCD or SCD1) produces monounsaturated fatty acids by introducing double bonds into saturated bonds between carbons 9 and 10,with oleic acid as the main product. SCD1 is present in the intestinal epithelium,and fatty acids regulate cell proliferation,so we investigated the effects of SCD1-induced production of oleic acid in enterocytes in mice. METHODS We generated mice with disruption of Scd1 selectively in the intestinal epithelium (iScd1-/- mice) on a C57BL/6 background; iScd1+/+ mice were used as controls. We also generated iScd1-/-ApcMin/+ mice and studied cancer susceptibility. Mice were fed a chow,oleic acid-deficient,or oleic acid-rich diet. Intestinal tissues were collected and analyzed by histology,reverse transcription quantitative polymerase chain reaction,immunohistochemistry,and mass spectrometry,and tumors were quantified and measured. RESULTS Compared with control mice,the ileal mucosa of iScd1-/- mice had a lower proportion of palmitoleic (C16:1 n-7) and oleic acids (C18:1 n-9),with accumulation of stearic acid (C18:0); this resulted a reduction of the Delta9 desaturation ratio between monounsaturated (C16:1 n-7 and C18:1 n-9) and saturated (C16:0 and C18:0) fatty acids. Ileal tissues from iScd1-/- mice had increased expression of markers of inflammation activation and crypt proliferative genes compared with control mice. The iScd1-/-ApcMin/+ mice developed more and larger tumors than iScd1+/+ApcMin/+ mice. iScd1-/-ApcMin/+ mice fed the oleic acid-rich diet had reduced intestinal inflammation and significantly lower tumor burden compared with mice fed a chow diet. CONCLUSIONS In studies of mice,we found intestinal SCD1 to be required for synthesis of oleate in the enterocytes and maintenance of fatty acid homeostasis. Dietary supplementation with oleic acid reduces intestinal inflammation and tumor development in mice. View Publication

PURPOSE Targeting nonspecific,tumor-associated antigens (TAA) with chimeric antigen receptors (CAR) requires specific attention to restrict possible detrimental on-target/off-tumor effects. A reduced affinity may direct CAR-engineered T (CAR-T) cells to tumor cells expressing high TAA levels while sparing low expressing normal tissues. However,decreasing the affinity of the CAR-target binding may compromise the overall antitumor effects. Here,we demonstrate the prime importance of the type of intracellular signaling on the function of low-affinity CAR-T cells. EXPERIMENTAL DESIGN We used a series of single-chain variable fragments (scFv) with five different affinities targeting the same epitope of the multiple myeloma-associated CD38 antigen. The scFvs were incorporated in three different CAR costimulation designs and we evaluated the antitumor functionality and off-tumor toxicity of the generated CAR-T cells in vitro and in vivo. RESULTS We show that the inferior cytotoxicity and cytokine secretion mediated by CD38 CARs of very low-affinity (Kd {\textless} 1.9 × 10-6 mol/L) bearing a 4-1BB intracellular domain can be significantly improved when a CD28 costimulatory domain is used. Additional 4-1BB signaling mediated by the coexpression of 4-1BBL provided the CD28-based CD38 CAR-T cells with superior proliferative capacity,preservation of a central memory phenotype,and significantly improved in vivo antitumor function,while preserving their ability to discriminate target antigen density. CONCLUSIONS A combinatorial costimulatory design allows the use of very low-affinity binding domains (Kd {\textless} 1 mumol/L) for the construction of safe but also optimally effective CAR-T cells. Thus,very-low-affinity scFvs empowered by selected costimulatory elements can enhance the clinical potential of TAA-targeting CARs. View Publication

OBJECTIVES Anti-citrullinated protein antibodies (ACPAs) are a group of autoantibodies targeted against citrullinated proteins/peptides and are informative rheumatoid arthritis (RA) biomarkers. ACPAs also play a crucial role in RA pathogenesis,and their underlying mechanism merits investigation. METHODS Immunohistochemical (IHC) assays were carried out to determine IL-1beta levels in ACPA+ and ACPA- RA patients. PBMC-derived monocytes were differentiated into macrophages before stimulation with ACPAs purified from RA patients. The localization and interaction of molecules were analyzed by confocal microscopy,co-IP,and surface plasmon resonance. RESULTS In our study,we found that IL-1beta levels were elevated in ACPA+ RA patients and that ACPAs promoted IL-1beta production by PBMC-derived macrophages. ACPAs interacted with CD147 to enhance the interaction between CD147 and integrin beta1 and,in turn,activate the Akt/NF-kappaB signaling pathway. The nuclear localization of p65 promoted the expression of NLRP3 and pro-IL-1beta,resulting in priming. Moreover,ACPA stimulation activated pannexin channels,leading to ATP release. The accumulated ATP bound to the P2X7 receptor,leading to NLRP3 inflammasome activation. CONCLUSIONS Our study suggests a new hypothesis regarding IL-1beta production in RA involving ACPAs,which may be a potential therapeutic target in RA treatment. View Publication

Systemic lupus (SLE) is characterized by a break of B cell tolerance that plays a central role in disease pathophysiology. An early checkpoint defect occurs at the transitional stage leading to the survival of autoreactive B cells and consequently the production of pathogenic autoantibodies. The main purpose of our work was to determine whether transitional B cells,as the most immature na{\{i}}ve B cell subset upstream of pathogenic B cells display specific features compared to healthy non SLE subjects. Through extensive analysis of transitional B cells from untreated or low treated mostly Caucasian SLE patients we demonstrated that transitional (T1 and T2) B cell frequencies were increased in SLE and positively correlated with disease activity. SLE transitional B cells displayed defects in two closely inter-related molecules (i.e. TLR9 defective responses and CD19 downregulation). RNA sequencing of sorted transitional B cells from untreated patients revealed a predominant overexpression of interferon stimulated genes (ISGs) even out of flares. In addition early transitional B cells from the bone marrow displayed the highest interferon score reflecting a B cell interferon burden of central origin. Hence the IFN signature in transitional B cells is not confined to African American SLE patients and exists in quiescent disease since the medullary stage. These results suggest that in SLE these 3 factors (i.e. IFN imprintment CD19 downregulation and TLR9 responses impairment) could take part at the early transitional B cell stage in B cell tolerance by-pass ultimately leading in periphery to the expansion of autoantibodies-secreting cells." View Publication

BACKGROUND AIMS microRNAs (miRNAs) are small non-coding RNAs that bind to 3'UTR regions of mRNAs to promote their degradation or block their translation. Mice with disruption of the trefoil factor 1 gene (Tff1) develop gastric neoplasms. We studied these mice to identify conserved miRNA networks involved in gastric carcinogenesis. METHODS We performed next-generation miRNA sequencing analysis of normal gastric tissues (based on histology) from subjects without evidence of gastric neoplasm from patients (n=64) and TFF1-knockout mice (n=22). We validated our findings using 270 normal gastric tissues (including 61 samples from patients without evidence of neoplastic lesions) and 234 gastric tumor tissues from 3 separate cohorts of patients and from mice. We performed molecular and functional assays using cell lines (MKN28,MKN45,STKM2,and AGS cells),gastric organoids,and mice with xenograft tumors. RESULTS We identified 117 miRNAs that were significantly deregulated in mouse and human gastric tumor tissues,compared with non-tumor tissues. We validated changes in levels of 6 miRNAs by quantitative real-time PCR analyses of neoplastic gastric tissues from mice (n=39) and 3 independent cohorts patients (332 patients total). We found levels of MIR135B-5p,MIR196B-5p,and MIR92A-5p to be increased in tumor tissues whereas levels of MIR143-3p,MIR204-5p,and MIR133-3p were decreased in tumor tissues. Levels of MIR143-3p were reduced not only in gastric cancer tissues,but also in normal tissues adjacent to tumors in humans and low-grade dysplasia in mice. Transgenic expression of MIR143-3p in gastric cancer cell lines reduced their proliferation and restored their sensitivity to cisplatin. AGS cells with stable transgenic expression of MIR143-3p grew more slowly as xenograft tumors in mice than control AGS cells; tumor growth from AGS cells that expressed MIR143-3p,but not control cells,was sensitive to cisplatin. We identified and validated bromodomain containing 2 (BRD2) as a direct target of MIR143-3p; increased levels of BRD2 in gastric tumors associated with shorter survival times of patients. CONCLUSIONS In an analysis of miRNA profiles of gastric tumors from mice and human patients,we identified a conserved signature associated with early stages of gastric tumorigenesis. Strategies to restore MIR143-3p or inhibit BRD2 might be developed for treatment of gastric cancer. View Publication

Aneurysms and dissections affecting thoracic aorta are associated with smooth muscle cell (SMC) dysfunction. NO/cGMP signaling pathway in smooth muscle cells has been shown to be affected in sporadic thoracic aortic aneurysms. We analyzed the mRNA levels of PDE5,a cGMP-hydrolyzing enzyme highly expressed in aortic SMCs,that regulates arterious vascular tone by lowering cGMP levels. We found that aortic tissue obtained from Marfan,tricuspid and bicuspid thoracic aneurysms expressed lower levels of PDE5 mRNA compared to control aortas. In particular,we found that affected aortas showed lower levels of all the PDE5A isoforms,compared to control aortas. Transfection of vascular SMCs (VSMCs) with NOTCH3 activated domain (NICD3) induced the expression of PDE5A1 and A3 protein isoforms,but not that of the corresponding mRNAs. VSMC stimulation with GSNO,a nitric oxide analogue or with 8-br-cGMP,but not with 8-br-cAMP,up-regulated PDE5 and NOTCH-3 protein levels,indicating a negative feedback loop to protect the arterial wall from excessive relaxation. Finally,we found that PDE5 is expressed early during human aorta development,suggesting that if loss of function mutations of PDE5 occur,they might potentially affect aortic wall development. View Publication