The Von Willebrand Factor Antigen Plasma Concentration: a Monitoring Marker in the Treatment of Aortic and Mitral Valve Diseases.

Von Willebrand disease is a commonly inherited bleeding disorder caused by defects of von Willebrand factor (vWF). In the most common valve diseases, aortic valve stenosis (AVS) and mitral valve regurgitation (MVR), a bleeding tendency has been described in a number of patients. This has been associated to a high turbulence of blood flow through the compromised valve, promoting degradation of vWF with loss of high-molecular-weight multimers of vWF (HMWM), leading to an acquired von Willebrand syndrome (AvWS). We analysed three groups of patients, one affected by AVS, treated with transcatheter aortic valve implantation (TAVI), the second group of patients affected by MVR, treated with Mitraclip® mitral valve repair. The third group was represented by patients also affected by AVS, but not eligible for TAVI and treated with standard surgery. A fourth group of patients that underwent percutaneous coronary intervention (PCI) with stenting was used as a control. Our results demonstrated that the level of vWF measured as antigen concentration (vWF:Ag) increases in all cohorts of patients after treatment, while in control PCI patients, no modification of vWF:Ag has been registered. Western blot analysis showed only a quantitative loss of vWF in the pre-treatment time, but without significant HMWM modification. The monitoring of the vWF:Ag concentration, but not the quality of HMWM, can indicate the status of blood flow in the treated patients, thus introducing the possibility of using the vWF antigen detection in monitoring the status of replaced or repaired valves.

Role of the TAp63 Isoform in Recurrent Nasal Polyps.

The pathogenic molecular mechanisms underlying the insurgence of nasal polyps has not been completely defined. In some patients, these lesions can have a recurrence after surgery removal, and the difference between recurrent and not recurrent patients is still unclear. To molecularly characterize and distinguish between these two classes, a cohort of patients affected by nasal polyposis was analysed. In all patients we analysed the p63 isoform expression using fresh tissues taken after surgery. Moreover, confocal immunofluorescence analysis of fixed sections was performed. The results show high ΔNp63 expression in samples from the nasal polyps of patients compared to the normal epithelia. Analysis of the expression level of the TAp63 isoform shows differential expression between the patients with recurrence compared to those not recurring. The data, considered as the ΔN/TAp63 ratio, really discriminate the two groups. In fact, even though ΔNp63 is expressed in non-recurrent patients, the resulting ratio ΔN/TAp63 is significantly lower in these patients. This clearly indicates that the status of TAp63 expression, represented by the ΔN/TAp63 ratio, could be considered a prognostic marker of low recurrence probability. In these samples we also investigated the expression of OTX2 transcription factor, known to be a selective activator of TAp63, detecting a significant correlation. Database analysis of HNSCC patients showed increased survival for the patients presenting OTX2 amplification and/or overexpression. These results, together with the fact that TAp63 can be selectively upregulated by HDAC inhibitors, open the possibility to consider local treatment of recurrent nasal polyps with these molecules.

Cutaneous mosaicism, in KRT1 pI479T patient, caused by the somatic loss of the wild-type allele, leads to the increase in local severity of the disease.

BACKGROUND: Epidermolytic ichthyosis (BCIE, OMIM 113800), is an autosomal dominant disorder of the skin caused by mutations in keratin genes KRT1 and KRT10. We present two sporadic patients showing a mild diffuse ichthyosis with palmoplantar keratoderma. Interestingly, one of them shows a significant hyperkeratosis of palms and soles similar to those present in the Meleda disease (OMIM 248300). OBJECTIVE: In this paper we would clarify the genetic difference between the two patients, giving rise to the different phenotype. METHODS: Clinical evaluation, followed by histological and molecular analysis has been established for these patients. RESULTS: We demonstrated the presence of a genetic cutaneous mosaicism. Both patients carry the KRT1 pI479T substitution, but in the palmoplantar areas of one of them, only the mutated allele is expressed (hemizygous). This leads to highlight a new type of cutaneous mosaic, the palmoplantar mosaicism.

Progressive late-onset of cutaneous angiomatosis as possible sign of cerebral cavernous malformations.

BACKGROUND: Cerebral cavernous malformations (CCM) comprise enlarged capillary cavities in the central nervous system, with possible retinal or cutaneous vascular malformations. This condition is associated with CCM1, CCM2, and CCM3 gene mutations. OBJECTIVE: Cutaneous clinical, histological and cerebral MRI findings, including CCM1, CCM2, and CCM3 gene sequencing, of two unrelated, neurological symptom-free patients who consulted for late-onset of deep multiple cutaneous angiomatoid lesions, are described. RESULTS: The diagnosis of multiple cutaneous angiomatosis was confirmed and related to CCM as detected by MRI in both cases. Analysis of our patients showed normal nucleotide sequences of the genes proposed. CONCLUSIONS: A progressive late-onset of multiple, deep cutaneous venous malformations may indicate the need to investigate a potential coexistence of CCM by MRI. Early diagnosis and prompt treatment is required in these patients. The absence of CCM1, CCM2, and CCM3 mutations might indicate that different genes could be involved in the pathogenesis of these late-onset patients. Careful questioning about family history of CCM is important; our first patient's daughter had a history of cerebral cavernoma.

Two new p73 splice variants, gamma and delta, with different transcriptional activity.

p73 has been recently identified as a new structural and functional homologue of the transcription factor p53. It is expressed in either a full-length form, alpha, or a shorter beta mRNA variant, with exon 13 spliced out. Here we report the identification and functional characterization of two new p73 splicing variants, gamma (splicing out exon 11) and delta (splicing out exons 11, 12, and 13). Both gamma and delta p73 variants are expressed in human peripheral blood lymphocytes, primary keratinocytes, and different tumor cell lines, including neuroblastoma, glioblastoma, melanoma, hepatoma, and leukemia. The expression pattern of the four p73 splicing variants differs in both primary cells of different lineage and established cell lines even within the same type of tumor. A two-hybrid assay was used to characterize the homodimeric and heterodimeric interactions between the p73 variants, and showed that neither p73gamma nor p73delta interact with p53, whereas p73gamma showed strong interactions with all p73 isoforms, and p73delta binds efficiently p73alpha and p73gamma but only weakly p73beta. At the functional level, p73gamma is significantly less efficient in activating transcription of the p21(Waf1/Cip1) promoter than p53 or p73beta, whereas the effect of p73delta is intermediate and comparable to that of p73alpha. The ability of the different p73 variants to affect cell growth in p53 null osteosarcoma SAOS-2 cells correlates with their transcriptional activity on the p21(Waf1/Cip1) promoter: p73beta is the most efficient in inhibiting colony formation, whereas p73gamma is almost ineffective. Our results suggest that p73 isoforms may be differentially regulated, with four different isoforms capable of interacting among themselves and with p53. The relative expression level of each splice variant may modulate p73 transcriptional and growth suppression activities by affecting heterodimer formation.

Missense mutations in the TGM2 gene encoding transglutaminase 2 are found in patients with early-onset type 2 diabetes. Mutation in brief no. 982. Online.

Transglutaminase 2 (TG2 or TGM2) is a multi-functional enzyme which catalyzes transamidation reactions or acts as a G-protein in intracellular signalling. Tgm2-/- Mice lacking TG2 activity are glucose intolerant and show impairment of insulin secretion, suggesting an important physiological role for TG2 in the pancreatic beta cell. We have previously described a TGM2 heterozygous missense mutation ((c.998A>G, p.N333S) in a 14 year-old patient with insulin-treated diabetes and in his diabetic father. The aim of this study was to further investigate the role of TG2 in early-onset type 2 diabetes. We analysed the TGM2 gene in 205 patients with clinically defined Maturity Onset Diabetes of the Young (MODY) or early-onset type 2 diabetes. We found two novel heterozygous mutations (c.989T>G, p.M330R; c.992T>A, p.I331N), which were not detected in 300 normoglycemic controls. All mutations were in residues which are located close to the catalytic site and impaired transamidating activity in vitro. Gene expression of TGM family genes and localization of TG2 in normal human pancreas indicated that TG2 is the only transglutaminase significantly expressed in human pancreatic islet cells. We conclude that reduced TG2 activity can contribute to disorders of glucose metabolism possibly via an impairment of insulin secretion.

Differential roles of p63 isoforms in epidermal development: selective genetic complementation in p63 null mice.

Epidermal development requires the transcription factor p63, as p63-/- mice are born dead, without skin. The gene expresses two proteins, one with an amino-terminal transactivation domain (TAp63) and one without (deltaNp63), although their relative contribution to epidermal development is unknown. To address this issue, we reintroduced TAp63alpha and/or deltaNp63alpha under the K5 promoter into p63-/- mice by in vivo genetic complementation. Whereas p63-/- and p63-/-;TA mice showed extremely rare patches of poorly differentiated keratinocytes, p63-/-;deltaN mice showed significant epidermal basal layer formation. Double TAp63alpha/deltaNp63alpha complementation showed greater patches of differentiated skin; at the ultrastructural level, there was clear reformation of a distinct basal membrane and hemidesmosomes. At the molecular level, deltaNp63 regulated expression of genes characteristic of the basal layer (K14), interacting (by Chip, luc assay) with the third p53 consensus site. Conversely, TAp63 transcribed the upper layer's genes (Ets-1, K1, transglutaminases, involucrin). Therefore, the two p63 isoforms appear to play distinct cooperative roles in epidermal formation.

Luteolin-7-glucoside inhibits IL-22/STAT3 pathway, reducing proliferation, acanthosis, and inflammation in keratinocytes and in mouse psoriatic model.

The epidermis is a dynamic tissue in which keratinocytes proliferate in the basal layer and undergo a tightly controlled differentiation while moving into the suprabasal layers. The balance between keratinocyte proliferation, differentiation, and death is essential, and its perturbation can result in pathological changes. Some common skin diseases, such as psoriasis, are characterized by hyperproliferation accompanied by inflammatory reactions, suggesting that molecules with topical anti-inflammatory and ROS scavenging abilities may be useful for their treatment. Here we investigate the potential of the flavone Luteolin-7-glucoside (LUT-7G) as a treatment for psoriasis. We show that LUT-7G leads to a modification of the cell cycle and the induction of keratinocyte differentiation, with modification of energy, fatty acid, and redox metabolism. LUT-7G treatment also neutralizes the proliferative stimulus induced by the proinflammatory cytokines IL-22 and IL-6 in HEKn. Moreover, in the Imiquimod (IMQ) mouse model of psoriasis, topical administration of LUT-7G leads to a marked reduction of acanthosis and re-expression of epidermal differentiation markers. Dissection of the IL-22 signalling pathway, activated by IMQ treatment, demonstrates that LUT-7G impairs the nuclear translocation of phosphorylated (activated) STAT3, blocking the IL-22 signalling cascade. Thus LUT-7G appears to be a promising compound for the treatment of hyperproliferative and inflammatory skin diseases, such as psoriasis.

A mutation in the V1 domain of K16 is responsible for unilateral palmoplantar verrucous nevus.

Palmoplantar keratodermas are a group of heterogeneous diseases characterized by thickening, and marked hyperkeratosis, of the epidermis of the palms and soles. Palmoplantar keratodermas can be divided into four major classes: diffuse, focal, punctate, and palmoplantar ectodermal dysplasias. All forms are genetic diseases inherited as autosomal dominant disorders. We studied a patient exhibiting a localized thickening of the skin in parts of the right palm and the right sole, following Blaschko's lines, that does not fit into any classes already described. We sequenced the keratin 16 cDNA derived from skin biopsy material from affected and non affected palms. The keratin 16 cDNA sequence from lesional epidermis showed a 12 base pair deletion (309-320del), which deletes codons 104-107. The mutation is predicted to delete four amino acids, GGFA, from the V1 domain of the keratin 16 polypeptide, close to the 1A domain. Full-length keratin 16 cDNA sequence derived from the unaffected palm was completely normal, consistent with a postzygotic mutation as is suggested by the mosaicism observed. We defined this new clinical entity, "unilateral palmoplantar verrucous nevus", rather than localized or focal epidermolytic palmoplantar keratodermas, as the lesions are present only on one side of the body and follow Blaschko's lines. This study is a report of a mosaic mutation in keratin 16 and also the association of a mutation in the V1 domain of a type I keratin associated with a human disease.

A glutamine insertion in the 1A alpha helical domain of the keratin 4 gene in a familial case of white sponge nevus.

White Sponge Nevus (WSN) is a rare, autosomal dominant disorder that predominantly affects noncornified stratified squamous epithelia. Clinically, it is characterized by the presence of soft, white, and "spongy" plaques in the oral mucosa. The characteristic histopathologic features are epithelial thickening, parakeratosis, and vacuolization of the suprabasal layer of oral epithelial keratinocytes. Mutations in keratin 4 (K4) and keratin 13 (K13) genes have already been demonstrated to be responsible for WSN; the identification of new keratin mutations in a stratified squamous epithelia closely related to epidermis is of relevance for the understanding of the biochemistry of intermediate filaments, and for genotype phenotype correlations. In this study we investigated a 27-y-old, female Italian patient, affected by white asymptomatic oral plaques. Sequence analysis revealed a 3 bp (ACA) heterozygous insertion localized in the helix initiation motif of the 1A alpha helical domain of K4. We report this new K4 gene mutation and describe an amino acid insertion, in the 1A domain, responsible for a keratin disease.

Novel and recurrent mutations in the genes encoding keratins K6a, K16 and K17 in 13 cases of pachyonychia congenita.

Thirteen patients with pachyonychia congenita types 1 and 2 were studied, two of which had a family history of pachyonychia and 11 of which were sporadic cases. Heterozygous mis-sense or small in-frame insertion/deletion mutations were detected in the genes encoding keratins K6a, K16, and K17 in all cases. Three novel mutations, F174V, E472K, and L469R were found in the K6a gene. Two novel mutations, M121T and L128Q were detected in K16. Similarly, three novel mutations, L95P, S97del, and L99P were found in K17. In addition, we identified recurrent mutations N171del (three instances) and F174S in K6a and R94H in K17. Analysis of both phenotype and genotype data led to the following conclusions: (i) K6a or K16 mutations produce the pachyonychia congenita type 1 phenotype, whereas K17 (or K6b) mutations cause pachyonychia congenita type 2; (ii) the presence of pilosebaceous cysts following puberty is the best indicator of pachyonychia congenita type 2; (iii) prepubescent patients are more difficult to classify due to the lack of cysts; and (iv) natal teeth are indicative of pachyonychia congenita type 2, although their absence does not preclude the pachyonychia congenita type 2 phenotype. This study establishes useful diagnostic criteria for pachyonychia congenita types 1 and 2, which will help limit unnecessary DNA analysis in the diagnosis and management of this genetically heterogeneous group of genodermatoses.

A novel mutation in the keratin 13 gene causing oral white sponge nevus.

White sponge nevus (WSN) is an autosomal-dominantly inherited form of mucosal leukokeratosis. Defects in keratins, proteins that form the stress-bearing cytoskeleton in epithelia, have been shown to cause several epithelial fragility disorders. Recently, mutations in the genes encoding mucosal-specific keratins K4 and K13 were shown to be the underlying cause of WSN. We have studied a large Scottish family with 19 persons affected by WSN in four generations. The K4 locus was excluded by genetic linkage analysis; however, genetic linkage consistent with a K13 defect was obtained. Subsequently, a heterozygous missense mutation 335A>G was detected in exon 1 of the KRT13 gene, predicting the amino acid change N112S in the 1A domain of the K13 polypeptide. The mutation was confirmed in affected family members and was excluded from 50 unaffected people by restriction enzyme analysis. These results confirm that mucosal keratin defects are the cause of WSN.

PIR2/Rnf144B regulates epithelial homeostasis by mediating degradation of p21WAF1 and p63.

ΔNp63 is a transcription factor that is critical for the development of stratified epithelia and is overexpressed or amplified in >80% of squamous cell carcinomas (SCCs). We identified the RING finger E3 ubiquitin ligase PIR2/Rnf144b as a direct transcriptional target of ΔNp63α and showed that its expression parallels that of ΔNp63α in keratinocytes, SCC cell lines and SCCs. We used primary keratinocytes as a model system to investigate the function of PIR2/Rnf144b in stratified epithelia. Depletion of PIR2/Rnf144b severely impaired keratinocyte proliferation and differentiation, associated with accumulation of p21(WAF1/CIP1); a known target of PIR2/Rnf144b. More importantly, we found that PIR2/Rnf144b binds and mediates proteasomal degradation of ΔNp63α, generating a hitherto unknown auto-regulatory feedback loop. These findings substantiate PIR2/Rnf144b as a potentially critical component of epithelial homeostasis, acting downstream of ΔNp63α to regulate cellular levels of p21(WAF1/CIP1) and ΔNp63α.

Novel transglutaminase 1 mutations in patients affected by lamellar ichthyosis.

Lamellar Ichthyosis (LI) is a form of congenital ichthyosis that is caused by mutations in the TGM1 gene that encodes for the transglutaminase 1 (TG1) enzyme. Functional inactivation of TG1 could be due to mutations, deletion or insertions. In this study, we have screened 16 patients affected by LI and found six new mutations: two transition/transversion (R37G, V112A), two nonsense mutations and two putative splice site both leading to a premature stop codon. The mutations are localized in exons 2 (N-terminal domain), 5, 11 (central catalytic domain), and none is located in the two beta-barrel C-terminal domains. In conclusion, this study expands the current knowledge on TGM1 mutation spectrum, increasing the characterization of mutations would provide more accurate prenatal genetic counselling for parents at-risk individuals.

OTX1 expression in breast cancer is regulated by p53.

The p53 transcription factor has a critical role in cell stress response and in tumor suppression. Wild-type p53 protein is a growth modulator and its inactivation is a critical event in malignant transformation. It has been recently demonstrated that wild-type p53 has developmental and differentiation functions. Indeed an over-expression of p53 in tumor cells induces asymmetrical division avoiding self-renewal of cancer stem cells (CSCs) and instead promoting their differentiation. In this study, 28 human breast carcinomas have been analyzed for expression of wild-type p53 and of a pool of non-clustered homeobox genes. We demonstrated that orthodenticle homolog 1 gene (OTX1) is transcribed in breast cancer. We established that the p53 protein directly induces OTX1 expression by acting on its promoter. OTX1 has been described as a critical molecule for axon refinement in the developing cerebral cortex of mice, and its activity in breast cancer suggests a synergistic function with p53 in CSC differentiation. Wild-type p53 may regulate cellular differentiation by an alternative pathway controlling OTX1 signaling only in breast cancer cells and not in physiological conditions.

FLASH is required for histone transcription and S-phase progression.

Cajal bodies are nuclear subdomains that are involved in maturation of small ribonucleoproteins and frequently associate with small nuclear RNA and histone gene clusters in interphase cells. We have recently identified FADD-like IL-1beta-converting enzyme (FLICE) associated huge protein (FLASH) as an essential component of Cajal bodies. Here we show that FLASH associates with nuclear protein, ataxia-telangiectasia, a component of the cell-cycle-dependent histone gene transcription machinery. Reduction of FLASH expression by RNA interference results in disruption of the normal Cajal body architecture and relocalization of nuclear protein, ataxia-telangiectasia. Furthermore, FLASH down-regulation results in a clear reduction of histone transcription and a dramatic S-phase arrest of the cell cycle. Chromatin immunoprecipitation reveals that FLASH interacts with histone gene promoter sequences. These results identify FLASH as an important component of the machinery required for histone precursor mRNA expression and cell-cycle progression.

Intragenomic distribution and stability of transposable elements in euchromatin and heterochromatin of Drosophila melanogaster: non-LTR retrotransposon.

The intragenomic location of the elements of the I, G, jockey, F, and Doc transposon families has been studied by the Southern blot analysis, in 12 laboratory Drosophila melanogaster stocks. Elements located in euchromatin, heterochromatin, and on the Y chromosome are identified, and their stability has been assessed by comparing the autoradiographs detected in different stocks and analysis of individual flies. Evidence is shown suggesting that preferential location in euchromatin or heterochromatin and the distribution within heterochromatin are distinctive of transposon families. Elements located in heterochromatin can be unstable. These results are discussed in the context of the relationship between transposable elements and the host genome.