Identification of FECH gene multiple variations in two Chinese patients with erythropoietic protoporphyria and a review.

Erythropoietic protoporphyria (EPP), an autosomal dominant disease, is caused by partial deficiency of ferrochelatase (FECH), which catalyzes the terminal step of heme biosynthesis because of loss-of-function mutations in the FECH gene. To date, only a few cases have been described in Asia. In this study, we describe the clinical features of two Chinese patients with EPP, with diagnosis confirmed by the increase of free protoporphyrin in erythrocytes, detection of plasma fluorescence peak at 630-634 nm, and analysis of FECH gene mutations. Using gene scanning, we identified a small deletion in the FECH gene (c.973 delA) in one proband (patient A) and a pathogenic FECH mutation (c.1232 G>T) in the other (patient B) and also observed some nucleotide variations (c.798 C>G, c.921 A>G, IVS1-23 C>T, IVS3+23 A>G, IVS9+35 C>T, and IVS3-48 T>C) in these patients. The family pedigree of patient A was then established by characterization of the genotype of the patient's relatives. We also analyzed the potential perniciousness of the missense mutation with bioinformatic software, Polyphen and Sift. In summary, Chinese EPP patients have similar manifestations to those of Caucasians, and identification of the Chinese FECH gene mutations expands the FECH genotypic spectrum and may contribute to genetic counseling.

[Myr-RKEFAK Peptide Selectively Regulates Outside-in Signaling Transduction-related Functions in Human Platelets].

OBJECTIVE: To study the effect of interaction of the talin rod domain integrin binding site 2 with integrin ß3 on platelet signal transduction. METHODS: A peptide that mimics the membrane proximal α helix 6 residues R724 KEFAK729 of the integrin ß3 cytoplasmic tails was designed and synthesized, to which the myristoylation was covalently linked to the N-terminal of the peptide enabling membrane penetration. The effects of myr-RKEFAK peptide on the typical platelet outside-in signaling ovent (stable adhesion and spreading on immobilized fibrinogen, aggregation, fibrin clot retraction) and inside-out signaling events (soluble fibrinogen binding) were tested. RESULTS: myr-RKEFAK peptide dose-dependently inhibited platelet stable adhesion and spreading on immobilized fibrinogen, irreversible aggregation, as well as fibrin clot retraction, but not soluble fibrinogen binding and reversible phase of platelet aggregation. CONCLUSION: The cell-penetrating peptide myr-RKEFAK causes an inhibitory effect on integrin ß3 outside-in signaling-regulated platelets functions, but did not affect inside-out signaling-regulated platelets functions.

[Effect of the Integrin ß3 Cytoplasmic NITY Motif on α II bß3-Mediated Cell Functions in CHO Cell Model].

UNLABELLED: OBJLECTIVE: To investigate the effect of integrin ß3 cytoplasmic NITY motif on αIIbß3-mediated cell functions. METHODS: Stable Chinese hamster ovary (CHO) cell lines that co-express human wild type integrin αIIb and wild type ß3 or mutant ß3ΔNITY (ß3 deleting cytoplasmic NITY motif) were established. Expression of αIIb and ß3 were tested by Western blot and flow cytometry in CHO cell lines. Spreading and adhesion of stable cell lines on immobilized fibrinogen were examined. The co-immunoprecipitation was used to detect protein interactions. RESULTS: CHO-αIIbß3, CHO-αIIbß3ΔNITY cells were successfully established. The CHO cells transfected with wild type αIIbß3 had the ability of adhesion and spreading. Compared with CHO-αIIbß3 cells, CHO-αIIbß3ΔNITY cells showed an impaired capacity of adhesion but no significant difference was observed in spreading of adhered cells. The co-immunoprecipitation showed that kindlin-2 associated with wild type integrin αIIbß3. The ß3ΔNITY mutation substantially reduced kindlin-2 association. CONCLUSION: Deletion of NITY motif causes an impaired ability of adhesion. The deletion mutation can suppress kindlin-2 binding to integrin ß3, thereby partially inhibit the integrin ß3 signaling.

Multimodal imaging and clinical characteristics of bone lesions in POEMS syndrome.

POEMS syndrome is a rare plasmacyte-associated disease, one of the major diagnostic criteria of which is sclerotic bone lesion. To detect bone lesions in POEMS syndrome, which imaging method should be routinely applied and what characteristics they display are still unconfirmed. We analyzed clinical data and imaging characteristics of bone lesions in 22 patients with POEMS using multimodal methods, including conventional X-ray, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT). Images on X-ray and CT exhibited plaque-like high-density for osteosclerotic lesions and punched-out low-density appearance for osteolytic ones. X-ray had advantage in detecting bone lesions in skull, extremity long bones, clavicle, and scapula, while CT could display sharp outline of lesions and was more sensitive than X-ray in detecting the small lesions. Osteosclerotic lesions on MRI demonstrated decreased signal intensity on both T1 and T2-weighted sequences, while osteolytic lesions or osteolytic part of mixed lesions showed high signal intensity on T2-weighted sequences. MRI had same sensitivity as CT, but with superiority in distinguishing the active osteolytic lesions from the osteosclerotic ones. PET-CT showed (18)F-FDG uptake was normal in the majority of osteosclerotic lesions, and slightly increased in mixed ones, but obviously elevated in osteolytic ones. PET/CT was less sensitive in detecting osteosclerotic lesions than in detecting osteolytic ones. In conclusion, to detect bone lesions in POEMS, conventional X-ray scan should be first performed, further followed by more sensitive CT or MRI. PET-CT is optional when the osteolytic lesions are suspected.