Fetal microchimerism is not involved in the pathogenesis of lichen sclerosus of the vulva

OBJECTIVES: The aim of this study was to investigate a possible relationship between fetal cell microchimerism and lichen sclerosus of the vulva. We searched for the presence of male cells and DNA in vulval tissue samples. METHODS: Paraffin-embedded skin biopsy samples from 15 women affected with vulval lichen sclerosus who gave birth to at least one son were analyzed for the presence of microchimeric male cells using fluorescence in situ hybridization (FISH) and fluorescent PCR. We included three lichen sclerosus samples originating from women without male offspring, six vulval specimens without pathological finding originating from autopsies and seven male gingival specimens as controls. RESULTS: Nucleated cells containing Y-chromosome specific sequences were neither detected at any site of the lesions nor in normal vulval specimens by using FISH. These results were confirmed by the use of PCR amplification demonstrating only DNA sequences specific for the X chromosome. No female microchimerism was detected in the male gingival samples. CONCLUSION: Despite the limited number and size of the samples, we conclude that persistent male fetal cells are not involved in the pathogenesis of lichen sclerosus of the vulva, since we consistently could not detect Y-chromosome specific sequences by using two molecular techniques.     

Hierarchy of eosinophil chemoattractants: role of p38 mitogen-activated protein kinase

Several chemoattractants can regulate the recruitment of eosinophils to sites of inflammation, but the hierarchy among them is unknown. We observed here that eosinophil chemotaxis towards eotaxin or 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE) was amplified up to sixfold in the presence of prostaglandin (PG) D2. This effect was only seen in eosinophils, and not in neutrophils or basophils. Pretreatment with the chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH2) antagonist ramatroban prevented the PGD2 enhancement of eosinophil migrations. In contrast, eotaxin or 5-oxo-ETE inhibited the migration of eosinophils towards PGD2. 5-oxo-ETE enhanced the chemotaxis to eotaxin, while eotaxin had no effect on 5-oxo-ETE-induced migration. 5-oxo-ETE induced the phosphorylation of p38 mitogen-activated protein kinase, and inhibition of p38 mitogen-activated protein kinase by SB-202190 converted the effect of 5-oxo-ETE on the chemotaxis to PGD2 from inhibition to enhancement. The presence of blood or plasma markedly decreased the sensitivity of eosinophils to eotaxin or 5-oxo-ETE, while responses to PGD2 were unaltered. In conclusion, PGD2 might be an initial chemoattractant, since it maintains its potency in the circulation and augments the responsiveness of eosinophils to other chemoattractants. In contrast, eotaxin seems to be an end-point chemoattractant, since it has reduced efficacy in blood and is capable of down-modulating eosinophil responsiveness to other chemoattractants.     

Essential role of the synaptic vesicle protein synapsin II in formalin-induced hyperalgesia and glutamate release in the spinal cord

The synaptic vesicle protein synapsin II plays an important role in the regulation of neurotransmitter release and synaptic plasticity. Here, we investigated its involvement in the synaptic transmission of nociceptive signals in the spinal cord and the development of pain hypersensitivity. We show that synapsin II is predominantly expressed in terminals and neuronal fibers in superficial laminae of the dorsal horn (laminae I-II). Formalin injection into a mouse hindpaw normally causes an immediate and strong release of glutamate in the dorsal horn. In synapsin II deficient mice this glutamate release is almost completely missing. This is associated with reduced nociceptive behavior in the formalin test and in the zymosan-induced paw inflammation model. In addition, the formalin evoked increase in the number of c-Fos IR neurons is significantly reduced in synapsin II knockout mice. Touch perception and motor coordination, however, are normal indicating that synapsin II deficiency does not generally disrupt sensory and/or motor functions. Antisense-mediated transient knockdown of synapsin II in the spinal cord of adult animals also reduced the nociceptive behavior. As the antisense effect is independent of a potential role of synapsin II during development we suggest that the hypoalgesia in synapsin II deficient mice does involve a direct 'pain-facilitating' effect of synapsin II and is not essentially dependent on potentially occurring developmental alterations. The distinctive role of synapsin II for pain signaling probably results from its specific localization and possibly from a specific control of glutamate release.     

A comparison of wild-caught wood mice and bank voles in the Intellicage: assessing exploration, daily activity patterns and place learning paradigms

Our previous work has revealed very high baseline neurogenesis in the dentate gyrus of wood mice as compared particularly to bank voles; a difference which may be related to learning capacity. This study explored whether the newly-developed Intellicage system could be used to compare these species in simple spatial learning paradigms. The Intellicage is essentially a group-housing cage that also allows continuous automatic recording of each individual's behaviour. Seven wild-caught bank voles (Clethrionomys glareolus) were compared with seven wild-caught long-tailed wood mice (Apodemus sylvaticus) in the Intellicage system over 9 days. During the first 90 min after entering the cage, the wood mice were substantially more exploratory than the bank voles (P = 0.003). Over subsequent days, both species showed nocturnal activity increases with voles being 3.7 times more active overall. In the spatial learning paradigms, there were significant species-by-time interactions with wood mice outperforming bank voles on both place learning (P = 0.027) and subsequent reversal (P = 0.006). Conclusions are firstly that the wood mice show superior learning abilities in this paradigm, and secondly that the Intellicage serves as a valuable cognitive testing arena for small wild rodents, or for circumstances where cognition must be compared independent of different responses to handling or novel environments.     

Crystal structure of the complete core of archaeal signal recognition particle and implications for interdomain communication

Targeting of secretory and membrane proteins by the signal recognition particle (SRP) is evolutionarily conserved, and the multidomain protein SRP54 acts as the key player in SRP-mediated protein transport. Binding of a signal peptide to SRP54 at the ribosome is coordinated with GTP binding and subsequent complex formation with the SRP receptor. Because these functions are localized to distinct domains of SRP54, communication between them is essential. We report the crystal structures of SRP54 from the Archaeon Sulfolobus solfataricus with and without its cognate SRP RNA binding site (helix 8) at 4-A resolution. The two structures show the flexibility of the SRP core and the position of SRP54 relative to the RNA. A long linker helix connects the GTPase (G domain) with the signal peptide binding (M) domain, and a hydrophobic contact between the N and M domains relates the signal peptide binding site to the G domain. Hinge regions are identified in the linker between the G and M domains (292-LGMGD) and in the N-terminal part of the M domain, which allow for structural rearrangements within SRP54 upon signal peptide binding at the ribosome.     

Plectin-isoform-specific rescue of hemidesmosomal defects in plectin (-/-) keratinocytes

The various plectin isoforms are among the major crosslinking elements of the cytoskeleton. The importance of plectin in epithelia is convincingly supported by the severe skin blistering observed in plectin-deficient humans and mice. Here, we identified plectin 1a (> 500 kDa), a full length plectin variant containing the sequence encoded by the alternative first exon 1a, as the isoform most prominently expressed in human and mouse keratinocytes. In skin sections and cultured keratinocytes, plectin 1a was shown to colocalize with hemidesmosomal structures. In contrast, a second isoform expressed in epithelia, plectin 1c, differing from 1a merely by a short N-terminal sequence, colocalized with microtubules. Expression of plectin 1a, but not of its N-terminal fragment alone, or of a third alternative full length isoform (plectin 1), restored the reduced number of hemidesmosome-like stable anchoring contacts in cultured plectin-null keratinocytes. Our results show for the first time that different isoforms of a cytolinker protein expressed in one cell type perform distinct functions. Moreover, the identification of plectin 1a as the isoform defects in which cause skin blistering in plectin-related genetic diseases, such as epidermolysis bullosa simplex MD and epidermolysis bullosa simplex Ogna, could have implications for the future development of clinical therapies for patients.