Effect of allogeneic limbal mesenchymal stem cell therapy in corneal healing: role of administration route.

AIMS: To investigate whether allogeneic limbal mesenchymal stem cell (LMSC) therapy affects corneal healing after a severe chemical burn and whether the route of administration of LMSCs differs in its therapeutic effect in this respect. METHODS: A total of 60 Sprague-Dawley rats with clinically proven alkali injury were divided into four equal groups (n = 15) as follows: group 1: 2 × 10(5) cells/drop LMSCs, topically applied 6 times a day for 2 days; group 2: 2.4 × 10(6) cells in 0.5 ml LMSCs, subconjunctivally applied; group 3: 2.4 × 10(6) cells in 1 ml LMSCs, intraperitoneally applied, and group 4: no LMSC treatment. The groups were compared according to grades of corneal opacity (CO), corneal neovascularization (CNV) and corneal fluorescein staining (CFS). The migration of LMSCs into the cornea and the inflammatory characteristics of the groups were evaluated with BrdU (5-bromo-2'-deoxyuridine bromodeoxyuridine) immunostaining and histopathologically in a 4-week follow-up. RESULTS: There were statistically significant differences between the LMSC-treated and control groups in each week regarding mean CO scores and in the 3rd week regarding the mean CNV and CFS scores (p < 0.05). The statistical significance was due to the differences between the topical and the control group and between the subconjunctival and the control group. BrdU+ LMSCs were seen in the corneal epithelium of the all LMSC-administered rats, and fewer inflammatory changes were observed in these rats. CONCLUSION: Allogeneic LMSC treatment, especially topical and subconjunctival administration, seems to be helpful in affecting corneal healing after a severe corneal burn.

Nucleolar stress controls mutant Huntington toxicity and monitors Huntington's disease progression.

Transcriptional and cellular-stress surveillance deficits are hallmarks of Huntington's disease (HD), a fatal autosomal-dominant neurodegenerative disorder caused by a pathological expansion of CAG repeats in the Huntingtin (HTT) gene. The nucleolus, a dynamic nuclear biomolecular condensate and the site of ribosomal RNA (rRNA) transcription, is implicated in the cellular stress response and in protein quality control. While the exact pathomechanisms of HD are still unclear, the impact of nucleolar dysfunction on HD pathophysiology in vivo remains elusive. Here we identified aberrant maturation of rRNA and decreased translational rate in association with human mutant Huntingtin (mHTT) expression. The protein nucleophosmin 1 (NPM1), important for nucleolar integrity and rRNA maturation, loses its prominent nucleolar localization. Genetic disruption of nucleolar integrity in vulnerable striatal neurons of the R6/2 HD mouse model decreases the distribution of mHTT in a disperse state in the nucleus, exacerbating motor deficits. We confirmed NPM1 delocalization in the gradually progressing zQ175 knock-in HD mouse model: in the striatum at a presymptomatic stage and in the skeletal muscle at an early symptomatic stage. In Huntington's patient skeletal muscle biopsies, we found a selective redistribution of NPM1, similar to that in the zQ175 model. Taken together, our study demonstrates that nucleolar integrity regulates the formation of mHTT inclusions in vivo, and identifies NPM1 as a novel, readily detectable peripheral histopathological marker of HD progression.

Appraisal of childhood fever by German and Turkish mothers in Germany--results of a pilot study.

The cultural background of patients and parents is increasingly recognized as a relevant influence on health behavior. This study was conducted to test the validity and reliability of a questionnaire to investigate fever concepts among German and Turkish mothers living in Germany and to develop hypotheses on important correlations between cultural background and specific perceptions, explanations, fears, and measures taken when confronted with fever. We conducted 50 face-to-face interviews with Turkish and German mothers and 40 re-interviews by telephone. Validity of items was tested by discussion of videotaped interviews, cognitive interviewing and problem coding. To determine the reliability of items, Cohen's kappa was calculated. We found good results for validity and moderate to excellent results for reliability. The results of this pilot study indicate a relevant influence of the cultural background on the perception, explanation and treatment of childhood fever by mothers. However, a larger sample is required to adjust for educational and socioeconomic status.

Integration of the Deacetylase SIRT1 in the Response to Nucleolar Stress: Metabolic Implications for Neurodegenerative Diseases.

Understanding underlying mechanisms of neurodegenerative diseases is fundamental to develop effective therapeutic intervention. Yet they remain largely elusive, but metabolic, and transcriptional dysregulation are common events. Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD+)-dependent lysine deacetylase, regulating transcription, and critical for the cellular adaptations to metabolic stress. SIRT1 regulates the transcription of ribosomal RNA (rRNA), connecting the energetic state with cell growth and function. The activity of the transcription initiation factor-IA (TIF-IA) is important for the transcriptional regulation of ribosomal DNA (rDNA) genes in the nucleolus, and is also sensitive to changes in the cellular energetic state. Moreover, TIF-IA is responsive to nutrient-deprivation, neurotrophic stimulation, and oxidative stress. Hence, both SIRT1 and TIF-IA connect changes in cellular stress with transcriptional regulation and metabolic adaptation. Moreover, they finely tune the activity of the transcription factor p53, maintain mitochondrial function, and oxidative stress responses. Here we reviewed and discussed evidence that SIRT1 and TIF-IA are regulated by shared pathways and their activities preserve neuronal homeostasis in response to metabolic stressors. We provide evidence that loss of rDNA transcription due to altered TIF-IA function alters SIRT1 expression and propose a model of interdependent feedback mechanisms. An imbalance of this signaling might be a critical common event in neurodegenerative diseases. In conclusion, we provide a novel perspective for the prediction of the therapeutic benefits of the modulation of SIRT1- and nucleolar-dependent pathways in metabolic and neurodegenerative diseases.

Impaired rRNA synthesis triggers homeostatic responses in hippocampal neurons.

Decreased rRNA synthesis and nucleolar disruption, known as nucleolar stress, are primary signs of cellular stress associated with aging and neurodegenerative disorders. Silencing of rDNA occurs during early stages of Alzheimer's disease (AD) and may play a role in dementia. Moreover, aberrant regulation of the protein synthesis machinery is present in the brain of suicide victims and implicates the epigenetic modulation of rRNA. Recently, we developed unique mouse models characterized by nucleolar stress in neurons. We inhibited RNA polymerase I by genetic ablation of the basal transcription factor TIF-IA in adult hippocampal neurons. Nucleolar stress resulted in progressive neurodegeneration, although with a differential vulnerability within the CA1, CA3, and dentate gyrus (DG). Here, we investigate the consequences of nucleolar stress on learning and memory. The mutant mice show normal performance in the Morris water maze and in other behavioral tests, suggesting the activation of adaptive mechanisms. In fact, we observe a significantly enhanced learning and re-learning corresponding to the initial inhibition of rRNA transcription. This phenomenon is accompanied by aberrant synaptic plasticity. By the analysis of nucleolar function and integrity, we find that the synthesis of rRNA is later restored. Gene expression profiling shows that 36 transcripts are differentially expressed in comparison to the control group in absence of neurodegeneration. Additionally, we observe a significant enrichment of the putative serum response factor (SRF) binding sites in the promoters of the genes with changed expression, indicating potential adaptive mechanisms mediated by the mitogen-activated protein kinase pathway. In the DG a neurogenetic response might compensate the initial molecular deficits. These results underscore the role of nucleolar stress in neuronal homeostasis and open a new ground for therapeutic strategies aiming at preserving neuronal function.