Nicole Lièvre

Syndecan‐4 is a signaling molecule for stromal cell‐derived factor‐1 (SDF‐1)/ CXCL12

Stromal cell‐derived factor‐1 (SDF‐1)/CXCL12, the ligand for CXCR4, induces signal transduction. We previously showed that CXCL12 binds to high‐ and low‐affinity sites expressed by primary cells and cell lines, and forms complexes with CXCR4 as expected and also with a proteoglycan, syndecan‐4, but does not form complexes with syndecan‐1, syndecan‐2, CD44 or beta‐glycan. We also demonstrated the occurrence of a CXCL12‐independent heteromeric complex between CXCR4 and syndecan‐4. However, our data ruled out the glycosaminoglycan‐dependent binding of CXCL12 to HeLa cells facilitating the binding of this chemokine to CXCR4. Here, we demonstrate that CXCL12 directly binds to syndecan‐4 in a glycosaminoglycan‐dependent manner. We show that upon stimulation of HeLa cells by CXCL12, CXCR4 becomes tyrosine phosphorylated as expected, while syndecan‐4 (but not syndecan‐1, syndecan‐2 or beta‐glycan) also undergoes such tyrosine phosphorylation. Moreover, tyrosine‐phosphorylated syndecan‐4 from CXCL12‐stimulated HeLa cells physically coassociates with tyrosine phosphorylated CXCR4. Pretreatment of the cells with heparitinases I and III prevented the tyrosine phosphorylation of syndecan‐4, which suggests that the heparan sulfate‐dependent binding of SDF‐1 to this proteoglycan is involved. Finally, by reducing syndecan‐4 expression using RNA interference or by pretreating the cells with heparitinase I and III mixture, we suggest the involvement of syndecan‐4 and heparan sulfate in p44/p42 mitogen‐activated protein kinase and Jun N‐terminal/stress‐activated protein kinase activation by action of CXCL12 on HeLa cells. However, these treatments did not modify the calcium mobilization induced by CXCL12 in these cells. Therefore, syndecan‐4 behaves as a CXCL12 receptor, selectively involved in some transduction pathways induced by SDF‐1, and heparan sulfate plays a role in these events.

Black Patients of African Descent and HLA-DRB1*15:03 Frequency Overrepresented in Epidermolysis Bullosa Acquisita

Epidermolysis bullosa acquisita (EBA) is a rare autoimmune bullous disease (AIBD). However, higher EBA incidence and predisposing genetic factor(s) involving an HLA haplotype have been suspected in some populations. This retrospective study assessed the overrepresentation of black patients with EBA, its link with HLA-DRB1*15:03, and their clinical and immunological characteristics. Between 2005 and 2009, 7/13 (54%) EBA and 6/183 (3%) other-AIBD patients seen consecutively in our department were black (P=10(-6)); moreover 7/13 (54%) black patients and 6/183 (3%) white patients had EBA (P=10(-6)). In addition, between 1983 and 2005, 12 black patients had EBA. Finally, among the 19 black EBA patients, most of them had very atypical clinical presentations, 9 were natives of sub-Saharan Africa, 1 from Reunion Island, 7 from the West Indies, and 2 were of mixed ancestry. HLA-DRB1*15:03 allelic frequencies were 50% for African patients, significantly higher than the control population (P<10(-3)), and 21% for the West Indians (nonsignificant). High EBA frequencies have already been reported in American blacks significantly associated with the HLA-DR2. In conclusion, black-skinned patients developing EBA seem to have a genetic predisposition, and EBA should be suspected systematically for every AIBD seen in this population.

A prospective study of upper aerodigestive tract manifestations of mucous membrane pemphigoid.

Abstract: We conducted a prospective study between 1995 and 2002 to investigate nose and throat (NT) manifestations of mucous membrane pemphigoid (MMP). One hundred ten consecutive patients with clinical, histologic, and immunologic criteria of MMP were seen in 2 referral centers for bullous diseases. They were systematically asked about the existence of persistent NT symptoms. Patients who had any were examined with a flexible nasopharyngolaryngoscope by the same otorhinolaryngologist. When possible, NT mucous membrane (MM) biopsies were taken for direct immunofluorescence (IF) assays to determine lesion specificity. Thirty-eight (35%) patients (23 F/15 M; mean age, 58.5 yr) had the following NT symptoms: 35 (92%) nasal, 19 (50%) pharyngeal, and 10 (26%) laryngeal. Five (13%) had acute dyspnea. Thirty-three (87%) of the 38 symptomatic patients had lesions at physical examination: 30 (79%) nasal, 6 (16%) pharyngeal, and 19 (50%) laryngeal. Laryngeal involvement was asymptomatic in 11 patients. Lesions were mainly atrophic rhinitis and oropharyngeal and epiglottal erosions. Nasal valves, choanae, pharynx, and/or larynx were severely scarred in 7 (18%) patients, causing the death of 3. Direct IF showed malpighian epithelium associated with linear immune deposits (IgG, IgA, or C3) along the chorioepithelial junction in all 18 biopsies performed, including those of 4 symptomatic patients without lesions at physical examination. The presence of severe ophthalmologic lesions (p = 0.02) and ≥3 sites involved other than NT (p = 0.02) were predictive of laryngeal involvement. In contrast, laryngeal symptoms, disease duration, HLA DQB1*0301, and smoking were not significantly associated with laryngeal lesions. In conclusion, at least 35% of MMP patients had NT involvement. Atrophic rhinitis was the most frequent lesion. The most severe were the laryngeal lesions that were significantly associated with severe ocular involvement and disseminated disease, and could be fatal. Our results highlight the necessity of a multidisciplinary approach to MMP management to assure early diagnosis of NT involvement, to guide therapeutic choices, and to improve patient survival and functional outcomes. Abbreviations: BMZ = basement membrane zone, BP = bullous pemphigoid, EBA = epidermolysis bullosa acquisita, HLA = human leukocyte antigen, IEM = immunoelectron microscopy, IF = immunofluorescence, MM = mucous membrane, MMP = mucous membrane pemphigoid, NT = nose and throat, SSS = salt-split skin.

Carbodiimide versus Click Chemistry for Nanoparticle Surface Functionalization: A Comparative Study for the Elaboration of Multimodal Superparamagnetic Nanoparticles Targeting αvβ3 Integrins

Superparamagnetic fluorescent nanoparticles targeting αvβ3 integrins were elaborated using two methodologies: carbodiimide coupling and click chemistries (CuACC and thiol-yne). The nanoparticles are first functionalized with hydroxymethylenebisphonates (HMBP) bearing carboxylic acid or alkyne functions. Then, a large number of these reactives functions were used for the covalent coupling of dyes, poly(ethylene glycol) (PEG), and cyclic RGD. Several methods were used to characterize the nanoparticle surface functionalization, and the magnetic properties of these contrast agents were studied using a 1.5 T clinical MRI. The affinity toward integrins was evidenced by solid-phase receptor-binding assay. In addition to their chemoselective natures, click reactions were shown to be far more efficient than the carbodiimide coupling. The grafting increase was shown to enhance targeting affinity to integrin without imparing MRI and fluorescent properties.

Size-dependent nonlinear weak-field magnetic behavior of maghemite nanoparticles.

The magnetic behavior at room temperature of maghemite nanoparticles of variable sizes (from 7 to 20 nm) is compared using a conventional super quantum interference device (SQUID) and a recently patented technology, called MIAplex. The SQUID usually measures the magnetic response versus an applied magnetic field in a quasi-static mode until high field values (from -4000 to 4000 kA m(-1)) to determine the field-dependence and saturation magnetization of the sample. The MIAplex is a handheld portable device that measures a signal corresponding to the second derivative of the magnetization around zero field (between -15 and 15 kA m(-1)). In this paper, the magnetic response of the size series is correlated, both in diluted and powder form, between the SQUID and MIAplex. The SQUID curves are measured at room temperature in two magnetic field ranges from -4000 to 4000 kA m(-1) (-5T to 5T) and from -15 to 15 kA m(-1). Nonlinear behavior at weak fields is highlighted and the magnetic curves for diluted solutions evolve from quasi-paramagnetic to superparamagnetic behavior when the size of the nanoparticles increases. For the 7-nm sample, the fit of the magnetization with the Langevin model weighted with log-normal distribution corresponds closely to the magnetic size. This confirms the accuracy of the model of non-interacting superparamagnetic particles with a magnetically frustrated surface layer of about 0.5 nm thickness. For the other samples (10-nm to 21-nm), the experimental weak-field magnetization curves are modeled by more than one population of magnetically responding species. This behavior is consistent with a chemically uniform but magnetically distinct structure composed of a core and a magnetically active nanoparticle canted shell. Accordingly the weak-field signature corresponds to the total assembly of the nanoparticles. The impact of size polydispersity is also discussed.

Non‐Aqueous Sol–Gel Synthesis of Ultra Small Persistent Luminescence Nanoparticles for Near‐Infrared In Vivo Imaging

Ultra-small ZnGa2 O4 :Cr(3+) nanoparticles (6 nm) that exhibit near-infrared (NIR) persistent luminescence properties are synthesized by using a non-aqueous sol-gel method assisted by microwave irradiation. The nanoparticles are pegylated, leading to highly stable dispersions under physiological conditions. Preliminary in vivo studies show the high potential for these ultra-small ZnGa2 O4 :Cr(3+) nanoparticles to be used as in vivo optical nanotools as they emit without the need for in situ excitation and, thus, avoid the autofluorescence of tissues.

Oral cyclophosphamide without corticosteroids to treat mucous membrane pemphigoid

Background  Mucous membrane pemphigoid (MMP) still represents a potentially life‐ and sight‐threatening disease. Immunosuppressants, such as cyclophosphamide (CYC), are indicated for patients with severe and/or refractory MMP.

The manganese superoxide dismutase Ala16Val dimorphism modulates iron accumulation in human hepatoma cells.

The Ala/16Val dimorphism incorporates alanine (Ala) or valine (Val) in the mitochondrial targeting sequence of manganese superoxide dismutase (MnSOD), modifying MnSOD mitochondrial import and activity. In alcoholic cirrhotic patients, the Ala-MnSOD allele is associated with hepatic iron accumulation and an increased risk of hepatocellular carcinoma. The Ala-MnSOD variant could modulate the expression of proteins involved in iron storage (cytosolic ferritin), uptake (transferrin receptors, TfR-1 and-2), extrusion (hepcidin), and intracellular distribution (frataxin) to trigger hepatic iron accumulation. We therefore assessed the Ala/Val-MnSOD genotype and the hepatic iron score in 162 alcoholic cirrhotic patients. In our cohort, this hepatic iron score increased with the number of Ala-MnSOD alleles. We also transfected Huh7 cells with Ala-MnSOD-or Val-MnSOD-encoding plasmids and assessed cellular iron, MnSOD activity, and diverse mRNAs and proteins. In Huh7 cells, MnSOD activity was higher after Ala-MnSOD transfection than after Val-MnSOD transfection. Additionally, iron supplementation decreased transfected MnSOD proteins and activities. Ala-MnSOD transfection increased the mRNAs and proteins of ferritin, hepcidin, and TfR2, decreased the expression of frataxin, and caused cellular iron accumulation. In contrast, Val-MnSOD transfection had limited effects. In conclusion, the Ala-MnSOD variant favors hepatic iron accumulation by modulating the expression of proteins involved in iron homeostasis.

Comparison of 3 type VII collagen (C7) assays for serologic diagnosis of epidermolysis bullosa acquisita (EBA)

BACKGROUND Serologic diagnosis of epidermolysis bullosa acquisita (EBA) relies on the detection of circulating autoantibodies to type VII collagen (C7). OBJECTIVE We sought to compare the diagnostic performances of a commercialized enzyme-linked immunosorbent assay (ELISA) using C7 noncollagenous (NC) domains (C7-NC1/NC2 ELISA) and indirect immunofluorescence (IIF) biochip test on NC1-C7-expressing transfected cells (IIFT), with a full-length-C7 ELISA developed in our laboratory. METHODS C7-NC1/NC2 ELISA, IIFT, and full-length-C7 ELISA were run on 77 nonselected consecutive EBA sera. RESULTS C7-NC1/NC2 ELISA, IIFT, and full-length-C7 ELISA were positive, respectively, for: 30%, 27%, and 65% of the 77 sera; 43%, 32%, and 80% of 44 sera labeling the salt-split-skin (SSS) floor (F) by IIF (SSS/F(+)); 9%, 22%, and 47% of 32 SSS/F(-) sera; 28%, 28%, and 58% of classic EBA; 41%, 41%, and 82% of inflammatory EBA; and 18%, 0%, and 55% of mucous-membrane-predominant EBA. Significant differences for all sera were found between: the 2 ELISAs for the 77 sera, SSS/F(+) and SSS/F(-) sera, and IIFT versus full-length-C7 ELISA. LIMITATIONS The retrospective design was a limitation. CONCLUSION C7-NC1/NC2 ELISA and IIFT sensitivities for serologic diagnoses of EBA were low. Full-length-C7 ELISA was significantly more sensitive and could serve as a reference test.

Oesophageal involvement in 26 consecutive patients with mucous membrane pemphigoid

Oesophageal involvement of mucous membrane pemphigoid (MMP) has not yet been thoroughly described.