Spinocerebellar Ataxia in a Hungarian Female Patient with a Novel Variant of Unknown Significance in the CCDC88C Gene.

Spinocerebellar ataxia (SCA) 40 is an extremely rare subtype of the phenotypically and genetically diverse autosomal dominant ataxias caused by mutations of the CCDC88C gene. Most reported cases of SCA40 are characterized by late-onset cerebellar ataxia and variable extrapyramidal features; however, there is a report of a patient with early-onset spastic paraparesis as well. Here, we describe a novel missense CCDC88C mutation (p.R203W) in the hook domain of the DAPLE protein encoded by the CCDC88C gene that was identified in a female patient who developed late-onset ataxia, dysmetria and intention tremor. To explore the molecular consequences of the newly identified and previously described CCDC88C mutations, we carried out in vitro functional tests. The CCDC88C alleles were expressed in HEK293 cells, and the impact of the mutant DAPLE protein variants on JNK pathway activation and apoptosis was assessed. Our results revealed only a small-scale activation of the JNK pathway by mutant DAPLE proteins; however, increased JNK1 phosphorylation could not be detected. Additionally, none of the examined mutations triggered proapoptotic effect. In conclusion, we identified a novel mutation of the CCDC88C gene from a patient with spinocerebellar ataxia. Our results are not in accord with previous observations and do not support the primary role of the CCDC88C mutations in induction of JNK pathway activation in ataxia. Therefore, we propose that CCDC88C mutations may exert their effects through different and possibly in much broader, yet unexplored, biological processes.

Psoriasis-Associated Inflammatory Conditions Induce IL-23 mRNA Expression in Normal Human Epidermal Keratinocytes.

Psoriasis is a multifactorial, chronic inflammatory skin disease, the development of which is affected by both genetic and environmental factors. Cytosolic nucleic acid fragments, recognized as pathogen- and danger-associated molecular patterns, are highly abundant in psoriatic skin. It is known that psoriatic skin exhibits increased levels of IL-23 compared to healthy skin. However, the relationship between free nucleic acid levels and IL-23 expression has not been clarified yet. To examine a molecular mechanism by which nucleic acids potentially modulate IL-23 levels, an in vitro system was developed to investigate the IL-23 mRNA expression of normal human epidermal keratinocytes under psoriasis-like circumstances. This system was established using synthetic nucleic acid analogues (poly(dA:dT) and poly(I:C)). Signaling pathways, receptor involvement and the effect of PRINS, a long non-coding RNA previously identified and characterized by our research group, were analyzed to better understand the regulation of IL-23 in keratinocytes. Our results indicate that free nucleic acids regulate epithelial IL-23 mRNA expression through the TLR3 receptor and specific signaling pathways, thereby, contributing to the development of an inflammatory milieu favorable for the appearance of psoriatic symptoms. A moderate negative correlation was confirmed between the nucleic-acid-induced IL-23 mRNA level and the rate of its decrease upon PRINS overexpression.

TRAF3 and NBR1 both influence the effect of the disease-causing CYLD(Arg936X) mutation on NF-κB activity.

Recently described Hungarian and Anglo-Saxon pedigrees that are affected by CYLD cutaneous syndrome (syn: Brooke-Spiegler syndrome (BSS)) carry the same disease-causing mutation (c.2806C>T, p.Arg936X) of the cylindromatosis (CYLD) gene but exhibit striking phenotypic differences. Using whole exome sequencing, missense genetic variants of the TRAF3 and NBR1 genes were identified in the affected family members of the Hungarian pedigree that are not present in the Anglo-Saxon pedigree. This suggested that the affected proteins (TRAF3 and NBR1) are putative phenotype-modifying factors. An in vitro experimental system was set up to clarify how wild type and mutant TRAF3 and NBR1 modify the effect of CYLD on the NF-κB signal transduction pathway. Our study revealed that the combined expression of mutant CYLD(Arg936X) with TRAF3 and NBR1 caused increased NF-κB activity, regardless of the presence or absence of mutations in TRAF3 and NBR1. We concluded that increased expression levels of these proteins further strengthen the effect of the CYLD(Arg936X) mutation on NF-κB activity in HEK293 cells and may explain the phenotype-modifying effect of these genes in CYLD cutaneous syndrome. These results raise the potential that detecting the levels of TRAF3 and NBR1 might help explaining phenotypic differences and prognosis of CCS.

Sterigmatocystin production is restricted to hyphae located in the proximity of hülle cells.

Aspergillus nidulans produces sterigmatocystin, a secondary metabolite mycotoxin, for the protection of its reproductive structures. Previous studies on grazing behavior of fungivore arthropods, regulation of sexual development, and secondary metabolite biosynthesis have revealed the association of sterigmatocystin biosynthesis with sexual reproduction, but the spatial distribution of sterigmatocystin producing hyphae within the colony has never been investigated. In this work, we aimed to locate the site of sterigmatocystin production within the colony by employing a yCFP reporter system. We demonstrated that the stcO promoter is active only in vegetative hyphae that surround groups of hülle cells and the activity decreases and eventually ceases as the distance between the hypha and the hülle cells increases. This phenomenon indicates that the vegetative mycelium might consist of morphologically uniform, but functionally different hyphae.

The Psoriatic Nonlesional Skin: A Battlefield between Susceptibility and Protective Factors.

In the last two decades, large-scale gene-expression studies on psoriatic skin samples revealed that even though nonlesional skin is macroscopically identical to healthy skin, it harbors several molecular differences. Originally, these molecular differences were thought to represent susceptibility factors for plaque formation. However, we review in this paper the several factors of immune regulation and structural alteration that are specific for the nonlesional skin and serve as protective factors by counteracting plaque formation and contributing to the maintenance of the nonlesional phenotype.

Exosomal long non-coding RNAs as biomarkers in human diseases.

The intensive study of extracellular vesicles was started about a decade ago revealing alterations of their amount and content to several cellular stimuli, highly depending on the releasing cell type. Exosomes, a type of extracellular vesicles, are released by every cell type and are present in most body fluids, what makes them attractive targets of biomarker research. Several studies have indicated that their content - including proteins and coding, as well as non-coding nucleic acids - could represent the disease state and serves as specific disease biomarkers. Out of these molecules, a special interest was gained by long non-coding RNAs (lncRNAs). Just as exosomes, lncRNAs are specific to their cell of origin and often specific to diseases, also found extracellularly, mainly contained in extracellular vesicles. Thus, recent efforts in biomarker research has turned to circulating exosomal lncRNAs, which might lead to the development of highly specific disease markers. Here we summarize the current knowledge on disease-associated exosomal long non-coding RNAs. The intensive studies in this area have revealed numerous potential targets for biomarkers, and highlighted the potential of their combination with other exosomal markers to represent a highly sensitive and specific diagnostic tool. However, we believe that additional functional data on both exosomes and lncRNAs are necessary for understanding their deregulation in diseases and developing their use as diagnostic approaches.