Homing Molecules Research Articles

RETRACTED ARTICLE: TGFβ3 recruits endogenous mesenchymal stem cells to initiate bone regeneration

BackgroundThe recruitment of a sufficient number of endogenous mesenchymal stem cells (MSCs) is the first stage of in-situ tissue regeneration. Transforming growth factor beta-3 (TGFβ3) could recruit stem or progenitor cells and endothelial cells to participate in tissue regeneration. However, the mechanism of TGFβ3 recruiting MSCs toward bone regeneration has remained obscure.MethodsWe estimated the promigratory property of TGFβ3 on human bone marrow MSCs (hBMSCs) cocultured with the vascular cells (human umbilical artery smooth muscle cells or human umbilical vein endothelial cells) or not by Transwell assay. After the addition of the inhibitor (SB431542) or Smad3 siRNA, the levels of MCP1 and SDF1 in coculture medium were tested by ELISA kit, and then the migratory signaling pathway of hBMSCs induced by TGFβ3 was investigated by western blot analysis. In vivo, a 2-mm FVB/N mouse femur defect model was used to evaluate chemokine secretion, endogenous cell homing, and bone regeneration induced by scaffolds loading 1 μg TGFβ3 through qPCR, immunofluorescent staining, immunohistochemical analysis, and Micro-CT, compared to the vehicle group.ResultsTGFβ3 (25 ng/ml) directly showed a nearly 40% increase in migrated hBMSCs via the TGFβ signaling pathway, compared to the vehicle treatment. Then, in the coculture system of hBMSCs and vascular cells, TGFβ3 further upregulated nearly 3-fold MCP1 secretion from vascular cells in a Smad3-dependent manner, to indirectly enhance nearly more than 50% of migrated hBMSCs. In vivo, TGFβ3 delivery improved MCP1 expression by nearly 7.9-fold, recruited approximately 2.0-fold CD31+ vascular cells and 2.0-fold Sca-1+ PDGFR-α+ MSCs, and achieved 2.5-fold bone volume fraction (BV/TV) and 2.0-fold bone mineral density, relative to TGFβ3-free delivery.ConclusionsTGFβ3, as a MSC homing molecule, recruited MSCs to initiate bone formation in the direct-dependent and indirect-dependent mechanisms. This may shed light on the improvement of MSC homing in bone regeneration.

CCR6 promotes steady-state mononuclear phagocyte associationwith the intestinal epithelium, imprinting and immune surveillance.

The intestinal lamina propria (LP) contains antigen-presenting cells with features of dendritic cells and macrophages, collectively referred to as mononuclear phagocytes (MNPs). Association of MNPs with the epithelium is thought to play an important role in multiple facets of intestinal immunity including imprinting MNPs with the ability to induce IgA production, inducing the expression of gut homing molecules on T cells, facilitating the capture of luminal antigens and microbes, and subsequent immune responses in the mesenteric lymph node (MLN). However, the factors promoting this process in the steady state are largely unknown, and invivo models to test and confirm the importance of LP-MNP association with the epithelium for these outcomes are unexplored. Evaluation of epithelial expression of chemoattractants in mice where MNP-epithelial associations were impaired suggested CCL20 as a candidate promoting epithelial association. Expression of CCR6, the only known receptor for CCL20, was required for MNPs to associate with the epithelium. LP-MNPs from CCR6-/- mice did not display defects in acquiring antigen and stimulating T-cell responses in exvivo assays or in responses to antigen administered systemically. However, LP-MNPs from CCR6-deficient mice were impaired at acquiring luminal and epithelial antigens, inducing IgA production in B cells, inducing immune responses in the MLN, and capturing and trafficking luminal commensal bacteria to the MLN. These findings identify a crucial role for CCR6 in promoting LP-MNPs to associate with the intestinal epithelium in the steady state to perform multiple functions promoting gut immune homeostasis.

Carbon nanotubes functionalized with folic acid attached via biomimetic peptide linker.

Anchoring folic acid (FA) with a biomimetic peptidic linker resistant to proteolytic degradation to act as a homing device on functionalized carbon nanotubes. Ethylenediamine was attached to oxidized multiwalled carbon nanotubes (MWNTs) using 4-(4,6-dimethoxy-[1,3,5]triazin-2-yl)-4-methylmorpholinium tetrafluoroborate.FA was coupled with 6-aminohexanoic acid and derivatives of β-alanine, affording four intermediates, which connected to the MWNTs via peptidic linkers of various lengths. Biomimetic nanomaterials were produced with FA as a homing molecule. The structure and properties of the nanomaterials were analyzed, confirming the versatility of the peptides used as linkers. Conjugates of FA attached to MWNTs via peptide linkers prepared from β-alanine residues are resistant to proteolytic degradation. Viability in colon cancer cells and normal colonocytes confirmed their lack of cytotoxicity.

Pyrimido[4,5-b]indole derivatives and use thereof in the expansion of hematopoietic stem cells US2015011543 (a1): a patent evaluation

ABSTRACTIntroduction: There is an unmet need of strategies for ex-vivo expansion of hematopoetic stem cells (HSCs) without loss of their primitive nature or stemness. We evaluate here a patent that attempts to address this need via key small molecules 1 and 40 that possess a pyrimido[4,5-b]indole core.Areas covered: (i) Discussion on literature reports of diverse strategies for ex-vivo expansion of stem cells. (ii) Synthetic scheme to 1, and general synthetic schemes for compounds 1-55 reported in the patent application. (iii) Analysis of the in vitro biological data for 1 and 40. Highlight here is: 1 and 40 when used in combination with StemReginin1 (SR1), an established aryl hydrocarbon receptor antagonist known for ex-vivo HSC expansion, demonstrate better HSC expansion relative to SR1 alone. (iv) Analysis of the in vivo biological data for 1 and 40.Expert opinion: Compelling evidence on the molecular mechanism of action of 1 and 40 is not provided making it difficult to optimize this series. It is suggested here that combining these molecules with homing molecules will possibly improve overall engraftment time and hematopoietic recovery. The numerous literature reports and biological data indicates that these pyrimido[4,5-b]indole derivatives are promising candidates for the development of potential therapies for hematopoietic ailments.

Single and combined effect of retinoic acid and rapamycin modulate the generation, activity and homing potential of induced human regulatory T cells.

Adoptive transfer of CD4+CD25+FOXP3+ regulatory T cells (Treg cells) has been successfully utilized to treat graft versus host disease and represents a promising strategy for the treatment of autoimmune diseases and transplant rejection. The aim of this study was to evaluate the effects of all-trans retinoic acid (atRA) and rapamycin (RAPA) on the number, phenotype, homing markers expression, DNA methylation, and function of induced human Treg cells in short-term cultures. Naive T cells were polyclonally stimulated and cultured for five days in the presence of different combinations of IL-2, TGF-β1, atRA and RAPA. The resulting cells were characterized by the expression of FOXP3, activation, surface and homing markers. Methylation of the Conserved Non-coding Sequence 2 was also evaluated. Functional comparison of the different culture conditions was performed by suppression assays in vitro. Culturing naive human T cells with IL-2/TGFβ1 resulted in the generation of 54.2% of Treg cells (CD4+CD25+FOXP3+) whereas the addition of 100 nM atRA increased the yield of Treg cells to 66% (p = 0.0088). The addition of RAPA did not increase the number of Treg cells in any of these settings. Treg cells generated in the presence of atRA had an increased expression of the β7 integrin to nearly 100% of the generated Treg cells, while RAPA treated cells showed enhanced expression of CXCR4. The differential expression of homing molecules highlights the possibility of inducing Treg cells with differential organ-specific homing properties. Neither atRA nor RAPA had an effect on the highly methylated CNS2 sites, supporting reports that their contribution to the lineage stability of Treg cells is not mediated by methylation changes in this locus. Treg cells generated in the presence of RAPA show the most potent suppression effect on the proliferation of effector cells.

CD34-negative hematopoietic stem cells show distinct expression profiles of homing molecules that limit engraftment in mice and sheep.

We and others have reported that human hematopoietic stem cells (HSCs) are also present in the CD34-negative (CD34-) fraction of human cord blood (CB). Here, we examined the hematopoietic engraftment potential of 13 or 18 lineage-negative (13Lin- or 18Lin-) CD34+/- cells from human CB in mice and sheep. Both 13Lin- and 18Lin- CD34+ cells efficiently engrafted in mice irrespective of transplantation route, be it by tail-vein injection (TVI) or by intra-bone marrow injection (IBMI). These cells also engrafted in sheep after in utero fetal intra-hepatic injection (IHI). In contrast, neither 13Lin- nor 18Lin- CD34- cells engrafted in either mice or sheep when transplanted by regular routes (i.e., TVI and fetal IHI, respectively), although both 13Lin- and 18Lin- CD34- cells engrafted in mice when transplanted by IBMI and exhibited multilineage reconstitution ability. Thus, the homing ability of CD34- HSCs is significantly more limited than that of CD34+ HSCs. As for 18Lin-, CD34- HSCs are characterized by low expression of the tetraspanin CD9, which promotes homing, and high expression of the peptidase CD26, which inhibits homing. This unique expression pattern homing-related molecules on CD34- HSCs could thus explain in part their reduced ability to home to the BM niche.

The splenic marginal zone shapes the phenotype of leukemia B cells and facilitates their niche-specific retention and survival

ABSTRACT Microenvironmental regulation in lymphoid tissues is essential for the development of chronic lymphocytic leukemia. We identified cellular and molecular factors provided by the splenic marginal zone (MZ), which alter the migratory and adhesive behavior of leukemic cells. We used the Cxcr5−/−Eµ-Tcl1 leukemia mouse model, in which tumor cells are excluded from B cell follicles and instead accumulate within the MZ. Genes involved in MZ B cell development and genes encoding for adhesion molecules were upregulated in MZ-localized Cxcr5−/−Eµ-Tcl1 cells. Likewise, surface expression of the adhesion and homing molecules, CD49d/VLA-4 and CXCR7, and of NOTCH2 was increased. In vitro, exposing Eµ-Tcl1 cells or human CLL cells to niche-specific stimuli, like B cell receptor- or Toll-like receptor ligands, caused surface expression of these molecules characteristic for a follicular or MZ-like microenvironment, respectively. In vivo, inhibition of VLA-4-mediated adhesion and CXCL13-mediated follicular homing displaced leukemic cells not only from the follicle, but also from the MZ and reduced leukemia progression. We conclude that MZ-specific factors shape the phenotype of leukemic cells and facilitate their niche-specific retention. This strong microenvironmental influence gains pathogenic significance independent from tumor-specific genetic aberrations.

CD4+ T cells in PBMC to predict the outcome of anti-PD-1 therapy.

11525 Background: Antibody blockade of programmed death 1 (PD-1), has led to durable responses and significant prolongation of overall survival in metastatic cancers including non-small cell lung cancer (NSCLC). However, in clinical trials, response rates were as low as 20 %, and approximately 50 % of the patients did not achieve benefits to prolong progression free survival. These results bring us a hypothesis that there are subgroups with distinct pre-existing anti-tumor immunity resulting in different responses to anti-PD-1 therapy. We reported that effector T cells, which are capable of mediating antitumor reactivity, are primed in LNs draining growing tumors and that these T cells exclusively belong to the T cells that down-regulated CD62L (CD62Llow) subpopulation. In the absence of purified tumor antigenic proteins or peptides on many tumors, the expression of the homing molecule CD62L on T cells may serve as a surrogate marker for identifying tumor-specific immune cells. Methods: We analyzed the peripheral blood mononuclear cells (PBMC) of 50 consecutive NSCLC patients who were planned to be treated with anti-PD-1 Ab, Nivolumab after obtaining written informed consent. The patients received Nivolumab at a dose of 3 mg per kilogram of body weight every 2 weeks. Tumor response was assessed with the use of the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, at week 8 and every 8 weeks thereafter. Results: The NSCLC patients who achieved partial response (PR) or stable disease (SD) had significantly (p = 4.1x10-7) more CD62Llow CD4+ T cells in PBMC than progressive disease (PD) patients. The percentages of CD62Llow in CD4+ T cells provided sensitivity 92.9 %, and specificity 96.7 % to predict the patients who had PD. Moreover, SD patients had significantly (p = 0.0067) less regulatory T cell subpopulation than PR patients, thus, it was possible to predict PR from SD. Conclusions: These results show that the major differences in pre-existing immunity among PR, SD, and PD patients to anti-PD-1 Ab existed in CD4+ T cell balance between primed effector and regulatory T cells. Further characterization of CD62Llow CD4+ T cells including mRNA microarray, checkpoint molecules, and chemokine receptors is going on.

Biochemical Changes in the Niche Following Tumor Cell Invasion.

Metastatic cancer is the leading cause of all cancer related deaths. Prostate cancer (PCa) metastasizes preferentially to the bone marrow, specifically within the endosteal niche. Endosteal cells secrete homing molecules that may recruit PCa cells to the bone marrow. Once there, the biochemical signature of this niche regulates PCa fate including cellular dormancy or cell cycle arrest, reactivation and resistance to chemotherapeutics. Growth factors, interleukins, adhesion molecules, as well as extra-cellular matrix proteins can collectively change the phenotype of PCa cells. Understanding the biochemical signature of endosteal niche parasitism by PCa is imperative for the establishment of new and innovative therapeutic strategies. This review seeks to summarize these important niche signatures and the potential therapeutic approaches to target metastatic PCa within the bone marrow hematopoietic stem cell (HSC) niche. J. Cell. Biochem. 118: 1956-1964, 2017. © 2016 Wiley Periodicals, Inc.

The α4β1 Homing Pathway Is Essential for Ileal Homing of Crohn's Disease Effector T Cells In Vivo.

The precise mechanisms controlling homing of T effector (Teff) cells to the inflamed gut in Crohn's disease (CD) are still unclear, and clinical outcome data from patients with inflammatory bowel disease treated with the anti-α4β7 integrin antibody vedolizumab suggest differences between ulcerative colitis and CD. Expression of homing molecules was studied with flow cytometry and immunohistochemistry. Their functional role was investigated in in vitro adhesion assays and in a humanized mouse model of T cell homing to the inflamed gut in vivo. Despite in vitro blockade of CD Teff adhesion to mucosal vascular addressin cell adhesion molecule-1 (MadCAM-1) and in contrast to previous observations in ulcerative colitis, anti-α4β7 treatment did not result in reduced Teff cell homing to the colon in vivo. However, the integrin α4β1 was expressed in higher levels on Teffs from patients with CD compared with controls, while its expression in the peripheral blood declined, and its expression in the intestine increased during the course of clinical vedolizumab treatment. Consistently, adhesion of CD Teffs to vascular cell adhesion molecule-1 (VCAM-1) was blocked by inhibition of α4 and α4β1 in vitro. Moreover, in vivo homing of CD Teffs to the ileum was reduced by inhibition of α4 and α4β1 integrins, but not α4β7 integrins. Our findings suggest that Teff cell homing to the ileum through the axis α4β1-VCAM-1 is an essential and nonredundant pathway in CD in vivo, possibly affecting efficacy of clinical treatment with antiadhesion compounds.

A high migratory capacity of donor T-cells in response to the lymph node homing receptor CCR7 increases the incidence and severity of GvHD.

The pathogenesis of GvHD involves migration of donor T-cells into the secondary lymphoid organs in the recipient, which is steered by two homing molecules, CD62L and CCR7. Therefore, we investigated whether the migratory capacity of donor T-cells is associated with GvHD. This single center prospective study included 85 donor-recipient pairs. In vitro chemotaxis assays of the lymphocytes of the apheresis product were performed in parallel to the analysis of CD62L and CCR7 by flow cytometry. The migratory index to the CCR7 ligands, CCL19 and CCL21, was higher in T-cells from donors whose recipients will develop GvHD. Similarly, the acute GvHD (aGvHD) group received higher percentage of CD4+CCR7+ T-cells, whereas chronic GvHD (cGvHD) patients were transplanted with higher percentages of CD8+CCR7+ T-cells compared with the non-GvHD group. These results were confirmed when patients were subdivided according to degrees of severity. Further, multivariate analysis confirmed that the proportions of CCR7+ CD4+ and CCR7+ CD8+ T-cells are risk factors for the development and severity of aGvHD and cGvHD, respectively. Functional experiments demonstrated that CCR7+ T-cells exhibited higher potential for activation than CCR7- T-cells did. We therefore propose that the selective depletion of CCR7-expressing T-cells may be an effective preventive therapy for GvHD.

Effects of leptin and ghrelin on the expression of membrane molecules and cytokine production by NK cells from the peripheral blood

The influence of leptin and ghrelin, as well as their combined effects, on the expression of membrane molecules and cytokine production by NK cells from peripheral blood was studied in vitro. The effects of hormones were assayed at the concentrations corresponding to their peripheral blood levels in the course of physiological pregnancy. It was established that the investigated hormones exerted significant effects only at the concentrations typical of the II–III trimester of pregnancy. In particular, leptin and ghrelin and their combination increased the number of CD56brightNKp46+NK cells in the suspension of mononuclear cells and inhibited the expression of homing molecules CCR7 and inhibitor molecules LILRB in NKp46+NK cells. Leptin and its combination with ghrelin increased the expression of L-selectin in CD56brightNKp46+NK cells but inhibited the secretion of IL-10 by NKp46+NK cells. Leptin reduced the production of IL-4 by NKp46+ cells, while ghrelin eliminated this effect. The hormones did not influence the expression of inhibitory molecules NKG2A in NKp46+ cells and the production of TGF-β1, IL-17A, and IFN-γ by these cells. Thus, the investigated hormones at the concentrations typical of the II–III trimester of pregnancy effectively regulate the expression of membrane molecules and cytokine production by NK cells of the peripheral blood.

Receptor-Mediated Enhanced Cellular Delivery of Nanoparticles Using Recombinant Receptor-Binding Domain of Diphtheria Toxin

Antibodies and peptides are often used to home nanoparticles (NPs) to specific cells. Here in this work, we have used recombinant receptor-binding domain of diphtheria toxin (RDT) as a homing molecule for NPs. Diphtheria toxin binds to heparin binding EGF-like growth factor (HB-EGF) through its receptor-binding domain. HB-EGF is often overexpressed as cell surface molecule in various types of cancer. We have prepared monodispersed, spherical PLGA NPs and coated these NPs with RDT. These NPs are characterized by FESEM and FT-IR spectroscopy. Using flow cytometry and fluorescence spectroscopy, we show that coating with RDT increases cellular uptake of PLGA NPs. We further show that RDT-coated nanoparticles are internalized through clathrin-dependent receptor-mediated endocytosis that can be reduced by specific inhibitor. These RDT-coated nanoparticles (RDT-NP) were further used for preferential delivery of Irinotecan, a chemotherapeutic agent, to cells overexpressing HB-EGF. We show that receptor-mediated enhanced uptake of RDT-NPs increases the potency of irinotecan in these cells.

Oral Challenge with Wild-Type Salmonella Typhi Induces Distinct Changes in B Cell Subsets in Individuals Who Develop Typhoid Disease.

A novel human oral challenge model with wild-type Salmonella Typhi (S. Typhi) was recently established by the Oxford Vaccine Group. In this model, 104 CFU of Salmonella resulted in 65% of participants developing typhoid fever (referred here as typhoid diagnosis -TD-) 6–9 days post-challenge. TD was diagnosed in participants meeting clinical (oral temperature ≥38°C for ≥12h) and/or microbiological (S. Typhi bacteremia) endpoints. Changes in B cell subpopulations following S. Typhi challenge remain undefined. To address this issue, a subset of volunteers (6 TD and 4 who did not develop TD -NoTD-) was evaluated. Notable changes included reduction in the frequency of B cells (cells/ml) of TD volunteers during disease days and increase in plasmablasts (PB) during the recovery phase (>day 14). Additionally, a portion of PB of TD volunteers showed a significant increase in activation (CD40, CD21) and gut homing (integrin α4β7) molecules. Furthermore, all BM subsets of TD volunteers showed changes induced by S. Typhi infections such as a decrease in CD21 in switched memory (Sm) CD27+ and Sm CD27- cells as well as upregulation of CD40 in unswitched memory (Um) and Naïve cells. Furthermore, changes in the signaling profile of some BM subsets were identified after S. Typhi-LPS stimulation around time of disease. Notably, naïve cells of TD (compared to NoTD) volunteers showed a higher percentage of cells phosphorylating Akt suggesting enhanced survival of these cells. Interestingly, most these changes were temporally associated with disease onset. This is the first study to describe differences in B cell subsets directly related to clinical outcome following oral challenge with wild-type S. Typhi in humans.

Adhesion Molecules Associated with Female Genital Tract Infection.

Efforts to develop vaccines that can elicit mucosal immune responses in the female genital tract against sexually transmitted infections have been hampered by an inability to measure immune responses in these tissues. The differential expression of adhesion molecules is known to confer site-dependent homing of circulating effector T cells to mucosal tissues. Specific homing molecules have been defined that can be measured in blood as surrogate markers of local immunity (e.g. α4β7 for gut). Here we analyzed the expression pattern of adhesion molecules by circulating effector T cells following mucosal infection of the female genital tract in mice and during a symptomatic episode of vaginosis in women. While CCR2, CCR5, CXCR6 and CD11c were preferentially expressed in a mouse model of Chlamydia infection, only CCR5 and CD11c were clearly expressed by effector T cells during bacterial vaginosis in women. Other homing molecules previously suggested as required for homing to the genital mucosa such as α4β1 and α4β7 were also differentially expressed in these patients. However, CD11c expression, an integrin chain rarely analyzed in the context of T cell immunity, was the most consistently elevated in all activated effector CD8+ T cell subsets analyzed. This molecule was also induced after systemic infection in mice, suggesting that CD11c is not exclusive of genital tract infection. Still, its increase in response to genital tract disorders may represent a novel surrogate marker of mucosal immunity in women, and warrants further exploration for diagnostic and therapeutic purposes.

PWE-027 Feeding Tregs for Therapeutic In Vitro Expansion – Retinoic Acid not SCFA Provides The Best Diet

Introduction We have shown that Tregs expanded with rapamycin from FACS-sorted Crohn’s Disease (CD) peripheral blood (PB) CD4+CD25hiCD127loCD45RA+ precursors, yield an epigenetically stable FOXP3+ cell population that is resistant to pro-inflammatory cytokine expression.1 We will utilise this for a first in man clinical trial of Treg therapy for Crohn’s disease. We wished to optimise the expression of gut homing molecules on these cells as Tregs are required at the site of action for optimal suppressive ability. Methods Tregs were isolated from peripheral blood of CD patients and healthy controls. Retinoic acid (RA) and Rapamycin supplementation was tested in standard culture conditions as well as the addition of short chain fatty acids (SCFA). The effect of SCFA was assessed on ex-vivo expanded Tregs from CD4+CD25hiCD127loCD45RA+ precursors and induced Tregs (iTreg) from naive T cell precursors. The expression of gut homing molecules integrin b7 and GPR15 was assessed by flow cytometry. Suppressive ability was tested in vitro using autologous effector T cells (Teff). Parametric and non-parametric data were calculated as the mean±s.d. and median (interquartile range, IQR) respectively. For comparison of parametric and non-parametric data, t- test, one- or two-way ANOVA. Results In comparison to Rapamycin treated cells, the addition of RA significantly increased the expression of integrin beta 7 (38.7%±11.78% Rapamycin alone vs 72.26%±8.98% Rapamycin + RA p = 0.04, N = 7). RA treatment also significantly increased GPR15 expression. Cells treated with RA maintained their superior suppressive ability compared to Rapamycin treated Tregs (95.8%±3.5% vs 91.15%±10.1% p=ns; at Treg:Teff 1:1 ratio). SCFA treatment led to diminished cell viability and did not induce the expression of colonic homing molecule GPR15 in CD4+CD25hiCD127loCD45RA+ Tregs (74.4%±13.2% Rapamycin and RA treated culture vs 43.4%±17% with the addition of SCFA). Conclusion Contrary to existing evidence in mouse, SCFA did not increase the proportion of CD4+FOXP3+ Tregs in human iTreg cultures. In conclusion, the addition of Retinoic acid not SCFA provides the optimal conditions for ex-vivo Treg expansion for cell based therapy of Crohn’s disease. Reference 1 Canavan JB, Scotta C, Vossenkamper A, Goldberg R, Elder MJ, Shoval I, et al. Developing in vitro expanded CD45RA+ regulatory T cells as an adoptive cell therapy for Crohn’s disease. Gut. 2015. Disclosure of Interest None Declared

A role for CCR5+CD4 T cells in cutaneous psoriasis and for CD103+ CCR4+ CD8 Teff cells in the associated systemic inflammation

Recent results have identified critical components of the T cell response involved in the initiation and amplification phases of psoriasis. However the link between T cell responses arising in the skin and the systemic inflammation associated with severe psoriasis is largely unknown. We hypothesized that specific subsets of memory T cells recirculating from the skin could play a role. We therefore dissected the circulating memory T cell compartment in patients by analyzing the TCM, TEM and Teff phenotype, the pattern of CCR4 and CCR5 chemokine receptor expression and the expression of the tissue homing molecule CD103. For each subset we calculated the correlation with the Psoriasis Area and Severity Index (PASI) and with the extent of systemic inflammation measured as serum level of the prototypic short pentraxin, C reactive protein (CRP). Validation was performed by comparison with gene expression data in psoriatic plaques. We found that circulating CD103+CCR4+CCR5+ and CCR4+CCR6- CD8+ Teff cells, were highly correlated with CRP levels as well as with the validated index PASI, reflecting a link between skin involvement and systemic inflammation in patients with severe psoriasis. In addition we observed a contraction of circulating CCR5+ T cells in psoriasis patients, with a highly significant inverse correlation between CCR5+CD4 T cells and the PASI score. Increased expression of CCR5 and CCL5 genes in psoriatic skin lesions was consistent with an accumulation of CCR5+ cells in psoriatic plaques indicating a role for CCR5/CCL5 axis in disease pathogenesis.

VwF A3-GPI modification of EPCs accelerates reendothelialization of injured vessels via collagen targeting in mice

Despite the potential of endothelial progenitor cells (EPCs) to incorporate into sites of vessel injury and differentiate into endothelial cells, thereby contributing to the improvement of endothelial function, reendothelialization in some patients is insufficient for the prevention of abnormal endothelial growth because there is a lack of specific guided signals and low levels of congregation of the EPCs to the injured areas. If some type of molecular tool was able to guide EPCs specifically to the injured vessels, however, then the efficacy of cell implantation would improve. Here, we designed a strategy to modify these cells and improve their ability to directly target the injured vessels. As a homing molecule, we selected extracellular matrix components, such as collagen, which is exposed on catheter-injured arteries. To promote the adhesion of the EPCs to collagen, we painted the primary EPCs with a recombinant, glycosylphosphatidylinositol (GPI)-linked high-affinity ligand for collagen that is termed von Willebrand factor A3-GPI. These painted EPCs specifically bound to collagen in vitro and traveled to the damaged vessel in vivo. This novel strategy may allow for significant advancements in EPCs transplantation treatment.

Remodeling of the Host Cell Plasma Membrane by HIV-1 Nef and Vpu: A Strategy to Ensure Viral Fitness and Persistence.

The plasma membrane protects the cell from its surroundings and regulates cellular communication, homing, and metabolism. Not surprisingly, the composition of this membrane is highly controlled through the vesicular trafficking of proteins to and from the cell surface. As intracellular pathogens, most viruses exploit the host plasma membrane to promote viral replication while avoiding immune detection. This is particularly true for the enveloped human immunodeficiency virus (HIV), which assembles and obtains its lipid shell directly at the plasma membrane. HIV-1 encodes two proteins, negative factor (Nef) and viral protein U (Vpu), which function primarily by altering the quantity and localization of cell surface molecules to increase virus fitness despite host antiviral immune responses. These proteins are expressed at different stages in the HIV-1 life cycle and employ a variety of mechanisms to target both unique and redundant surface proteins, including the viral receptor CD4, host restriction factors, immunoreceptors, homing molecules, tetraspanins and membrane transporters. In this review, we discuss recent progress in the study of the Nef and Vpu targeting of host membrane proteins with an emphasis on how remodeling of the cell membrane allows HIV-1 to avoid host antiviral immune responses leading to the establishment of systemic and persistent infection.

Plasma cells as an innovative target in autoimmune disease with renal manifestations.

Autoantibodies are secreted by plasma cells and have an essential role in driving the renal manifestations of autoimmune diseases such as systemic lupus erythematosus and antineutrophil cytoplasmic autoantibody-associated vasculitis. Effective depletion of autoreactive plasma cells might be the key to curative treatment of these diseases. Two major plasma-cell compartments exist: short-lived plasmablasts or plasma cells, which result from differentiation of activated B cells, and long-lived plasma cells, which result from secondary immune responses. Long-lived plasma cells reside in survival niches in bone marrow and inflamed tissue and provide the basis of humoral memory and refractory autoimmune disease activity. Unlike short-lived plasmablasts, long-lived plasma cells do not respond to conventional immunosuppression or to therapies that target B cells. Existing therapies that target long-lived plasma cells, such as proteasome inhibitors and antithymocyte globulin, as well as promising approaches that target survival factors, cell homing or surface molecules, deplete the whole memory plasma cell pool, including cells that secrete protective antibodies. By contrast, we have developed a novel strategy that uses an affinity matrix to deplete pathogenic long-lived plasma cells in an autoantigen-specific manner without removing protective plasma cells. Targeting B-cell precursors to prevent replenishment of autoreactive long-lived plasma cells should also be considered.