Serum biomarker levels predict disability progression in patients with primary progressive multiple sclerosis.

BACKGROUND: We aimed to investigate the potential of serum biomarker levels to predict disability progression in a multicentric real-world cohort of patients with primary progressive multiple sclerosis (PPMS). METHODS: A total of 141 patients with PPMS from 18 European MS centres were included. Disability progression was investigated using change in Expanded Disability Status Scale (EDSS) score over three time intervals: baseline to 2 years, 6 years and to the last follow-up. Serum levels of neurofilament light chain (sNfL), glial fibrillar acidic protein (sGFAP) and chitinase 3-like 1 (sCHI3L1) were measured using single-molecule array assays at baseline. Correlations between biomarker levels, and between biomarkers and age were quantified using Spearman's r. Univariable and multivariable linear models were performed to assess associations between biomarker levels and EDSS change over the different time periods. RESULTS: Median (IQR) age of patients was 52.9 (46.4-58.5) years, and 58 (41.1%) were men. Median follow-up time was 9.1 (7.0-12.6) years. Only 8 (5.7%) patients received treatment during follow-up. sNfL and sGFAP levels were moderately correlated (r=0.43) and both weakly correlated with sCHI3L1 levels (r=0.19 and r=0.17, respectively). In multivariable analyses, levels of the three biomarkers were associated with EDSS changes across all time periods. However, when analysis was restricted to non-inflammatory patients according to clinical and radiological parameters (n=64), only sCHI3L1 levels remained associated with future EDSS change. CONCLUSIONS: Levels of sNfL, sGFAP and sCHI3L1 are prognostic biomarkers associated with disability progression in patients with PPMS, being CHI3L1 findings less dependent on the inflammatory component associated with disease progression.

Clinical and microbiological efficacy of tigecycline for complicated skin-soft-tissue and intra-abdominal infections in a Turkish university hospital.

OBJECTIVE: Tigecycline, a new glycylcycline antimicrobial agent, is indicated for the treatment of complicated skin structure infection (cSSTI), intra-abdominal infection (cIAI) and community acquired pneumonia. We aimed to evaluate the clinical and microbiological data together about tigecycline therapy. METHODS: Patients with cIAIs and cSSTIs were included in a prospective, observational follow-up. Patient follow-up forms were developed and clinical and microbiological data were recorded. RESULTS: Of the 107 patients, 67 had cSSTIs, 40 had cIAIs. Tigecycline was used empirically in 37.5% of cIAIs and in 50.7% of cSSTIs. In 85.0% of the patients with cIAI and in 73.1% of the patients with cSSTI, clinical and/or microbiological response could be achieved. A drug change was made in 26.9% and 7.5% of the patients with cSSTI and cIAI respectively. Superinfection was detected in 14.9% of the cSSTI and 7.5% of the cIAI patients. CONCLUSION: As a result, tigecycline can be safely used in the treatment of different infections. Compared with cSSTIs, the treatment response is better and the duration of treatment is shorter in cIAIs. However, MIC value must be determined at any rate if tigecycline is to be used in the treatment of Acinetobacter (MDR Acinetobacter, in particular) infections. Clinical cure and microbiological eradication rate of tigecycline therapy changes according to different clinical diagnosis and microorganism.

Cytokeratin 8 interacts with clumping factor B: a new possible virulence factor target.

Staphylococcus aureus is a human pathogen of growing clinical significance, owing to its increasing levels of resistance to most antibiotics. Infections range from mild wound infections to severe infections such as endocarditis, osteomyelitis and septic shock. Adherence of S. aureus to human host cells is an important step, leading to colonization and infection. Adherence is mediated by a multiplicity of proteins expressed on the bacterial surface, including clumping factor B. In this study, we aimed to identify new targets of clumping factor B in human keratinocytes by undertaking a genome-wide yeast two-hybrid screen of a human keratinocyte cDNA library. We show that clumping factor B is capable of binding cytokeratin 8 (CK8), a type II cytokeratin. Using a domain-mapping strategy we identified amino acids 437-464 as necessary for this interaction. Recombinantly expressed fragments of both proteins were used in pull-down experiments and confirmed the yeast two-hybrid studies. Analysis with S. aureus strain Newman deficient in clumping factor B showed the clumping factor B-dependence of the interaction with CK8. We postulate that the clumping factor B-CK8 interaction is a novel factor in S. aureus infections.

Aberrant heterodimerization of keratin 16 with keratin 6A in HaCaT keratinocytes results in diminished cellular migration.

Keratin filaments form obligatory heterodimers consisting of one type I and one type II keratin that build the intermediate filaments. In keratinocytes, type II keratin 6 (K6) interacts with type I keratin 16 (K16). We previously showed that the intermediate filament protein K16 is up-regulated in aged human skin. Here, we report that there is an obvious imbalance of K16 to K6 mRNA in in vivo and in vitro aging, which possibly leads to cellular effects. To unveil a possible biological function of K16 overexpression we investigated the migration potential of keratinocytes having up-regulated K16 expression in vitro. Two cell lines were established by transfection of human keratinocytes (HaCaT cells) with K16 or control vectors and subsequent fluorescence-activated cell sorting. By performing migration assays we were able to show a 90% reduction in the migration ability of the K16-overexpressing keratinocytes. In addition, a delay in wound closure associated with K16-overexpressing cells was shown by scratch assays. Transient overexpression of K6A in K16-overexpressing keratinocytes partially corrected the cell-migration defect. By real-time PCR we excluded co-regulation of the annotated interaction partner, K6, in the K16 cell line. Finally, we observed a decreased level of tyrosine phosphorylation in K16-overexpressing cells. Taken together, these data highlight the possibility of a physiological role for K6/K16 heterodimers in keratinocyte cell migration, in addition to the heterodimer's known functions in cell differentiation and mechanical resilience.

Nonsense-associated altered splicing of the Patched gene fails to suppress carcinogenesis in Gorlin syndrome.

Mutations in the gene coding for the transmembrane receptor protein Patched (PTCH) are implicated in the autosomal dominant disorder Gorlin syndrome (also known as naevoid basal cell carcinoma syndrome), characterized by congenital abnormalities and cancer predisposition. Tumour promotion is thought to be associated with aberrant function of PTCH, leading to misregulation of the hedgehog signalling network. However, the transcriptional events that underlie the reduced tumour suppression effects of PTCH have not been studied in detail. We describe a patient with Gorlin syndrome who had three molecular aberrations resulting in biallelic disruption of the PTCH gene, leading to abnormal protein expression and development of basal cell carcinoma. Remarkably, within tumour cells, the somatic nonsense mutation G1019X was associated with activation of a cryptic splice donor site, in which an in-frame deletion of the exon sequence containing the nonsense mutation occurred. However, the function of the resulting PTCH protein variant was still compromised. The pathogenetic alterations described give insights into the sequence of events leading to cellular transformation and underscore the importance of the PTCH protein in skin homeostasis.

GRC5 and NMD3 function in translational control of gene expression and interact genetically.

The yeast gene, GRC5 (growth control), is a member of the highly conserved QM gene family, the human member of which has been associated with the suppression of Wilms' tumor. GRC5 encodes ribosomal protein L10, which is thought to play a regulatory role in the translational control of gene expression. A revertant screen identified four spontaneous revertants of the mutant grc5-1ts allele. Genetic and phenotypic analysis showed that these represent one gene, NMD3, and that the interaction of NMD3 and GRC5 is gene-specific. NMD3 was previously identified as a component of the nonsense-mediated mRNA decay pathway. The point mutations within NMD3 reported here may define a domain important for the functional interaction of Grc5p and Nmd3p.