Naturally occurring degrading events in axon terminals of the dentate gyrus and stratum lucidum in the spiny mouse (Acomys cahirinus) during maturation, adulthood and aging.

Dawirs RR, Teuchert-Noodt G, Kacza J. Naturally occurring degrading events in axon terminals of the dentate gyrus and stratum lucidum in the spiny mouse (Acomys cahirinus) during maturation, adulthood and aging. Dev Neurosci. 1992;14(3):210-220.The naturally occurring dynamics of presynaptic axon terminals were investigated in the dentate gyrus and stratum lucidum of the spiny mouse (Acomys cahirinus) during maturation, adulthood and aging. A sensitive and selective silver-staining technique was applied to analyze neuronal lysosome accumulation (LA), indicating synaptic degradation during development. LA was quantified by counting silver grains in the inner third and outer two thirds of the molecular layer, granular layer, and the infragranular layer of the dentate gyrus, and in the strata oriens, pyramidale, lucidum and radiatum of the medial and distal regio inferior on postnatal days 21, 28, 95, 730, and 1,460. In young and adult animals, LA was most abundant within the inner molecular layer. When animals grew older, LA densities obviously decreased in the inner molecular layer but increased in the outer molecular layer. Within the stratum lucidum only the distal regio inferior showed an extremely high LA density on postnatal day 21, dramatically decreasing thereafter and reaching adult low values during the first postnatal month. By electron microscopy in the inner molecular layer we found LA in large synaptic boutons and small terminals both with distinct synaptic contact zones. Degrading presynaptic profiles may further accumulate dense bodies, zones with completely disorganized cytoplasm, and lamellarly organized whorled membrane debris. In the distal regio inferior comparable phenomena were observed in typical mossy fiber boutons. Despite these degrading events, no electron-dense degenerating terminals were found. These results on naturally occurring nondegenerative synaptic degradation are discussed with current concepts of synaptic turnover and remodelling in the developing, adult and aging brain

Equine bronchial fibroblasts enhance proliferation and differentiation of primary equine bronchial epithelial cells co-cultured under air-liquid interface

Interaction between epithelial cells and fibroblasts play a key role in wound repair and remodelling in the asthmatic airway epithelium. We present the establishment of a co-culture model using primary equine bronchial epithelial cells (EBECs) and equine bronchial fibroblasts (EBFs). EBFs at passage between 4 and 8 were seeded on the bottom of 24-well plates and treated with mitomycin C at 80% confluency. Then, freshly isolated (P0) or passaged (P1) EBECs were seeded on the upper surface of membrane inserts that had been placed inside the EBF-containing well plates and grown first under liquid-liquid interface (LLI) then under air-liquid interface (ALI) conditions to induce epithelial differentiation. Morphological, structural and functional markers were monitored in co-cultured P0 and P1 EBEC monolayers by phase-contrast microscopy, scanning and transmission electron microscopy, hematoxylin-eosin, immunocytochemistry as well as by measuring the transepithelial electrical resistance (TEER) and transepithelial transport of selected drugs. After about 15–20 days of co-culture at ALI, P0 and P1 EBEC monolayers showed pseudo-stratified architecture, presence of ciliated cells, typically honeycomb-like pattern of tight junction protein 1 (TJP1) expression, and intact selective barrier functions. Interestingly, some notable differences were observed in the behaviour of co-cultured EBECs (adhesion to culture support, growth rate, differentiation rate) as compared to our previously described EBEC mono-culture system, suggesting that cross-talk between epithelial cells and fibroblasts actually takes place in our current co-culture setup through paracrine signalling. The EBEC-EBF co-culture model described herein will offer the opportunity to investigate epithelial-mesenchymal cell interactions and underlying disease mechanisms in the equine airways, thereby leading to a better understanding of their relevance to pathophysiology and treatment of equine and human asthma

Apolipoproteins D and E3 exert neurotrophic and synaptogenic effects in dorsal root ganglion cell cultures

Co-cultures of 3T3-L1 adipocytes with neurons from the rat dorsal root ganglia (DRG) showed enhanced neuritogenesis and synaptogenesis. Microarray analysis for upregulated genes in adipocyte/DRG co-cultures currently points to apolipoproteins D and E (ApoD, ApoE) as influential proteins. We therefore tested adipocyte-secreted cholesterol and the carrier proteins ApoD and ApoE3. Cholesterol, ApoD, and ApoE3 each increased neurite outgrowth and upregulated the expression of presynaptic synaptophysin and synaptotagmin, as well as the postsynaptic density protein 95. The neurotrophic effects of ApoD and ApoE3 were associated with an increased expression of the low-density lipoprotein receptor and apolipoprotein E receptor 2. Simultaneous treatment with receptor-associated protein, an apolipoprotein receptor antagonist, inhibited the neurotrophic function of both apolipoproteins. The application of ApoD, ApoE3, and cholesterol to DRG cell cultures corresponded with increased expression of the chemokine stromal cell-derived factor 1 and its receptor CXC chemokine receptor 4 (CXCR4). Surprisingly, the inhibition of CXCR4 by the antagonistic drug AMD3100 decreased the apolipoprotein/cholesterol dependent neurotrophic effects. We thus assume that apolipoprotein-induced neuritogenesis in DRG cells interferes with CXCR4 signaling, and that adipocyte-derived apolipoproteins might be helpful in nerve repair

Surface properties of the skin of the pilot whale, Globicephala melas.

Abstract. - On the skin surface of delphinids small biofoulers are challenged to high shear water flow and liquid-vapor interfaces of air-bubbles during jumping. This state of self-cleaning is supported by the even, nano-rough gel-coated epidermal surface of the skin. In the present study we focussed on the topographic evolution of gel formation and the chemical composition of the gel smoothing the skin surface of the pilot whale, Globicephala melas. We employed photoelectron spectroscopy (XPS) in combination with cryo-scanning electron microscopy (CSM), and transmission electron microscopy (TEM).In the superficial layer of the epidermis, stratum corneum, intercellular material was shown by electron optical methods to assemble from smaller into larger covalently cross-linked aggregates during the transit of the corneocytes towards the skin surface. Employing XPS measurements, the surface of the skin and the intercellular gel included in approximately the same amount polar groups (especially, free amines and amides) and non-polar groups corresponding to the presence of lipid droplets dispersed within the jelly material.It was concluded from the results obtained that the gel-coat of the skin surface is a chemically heterogeneous skin product. The advantages of chemically heterogeneous patches contributing to the ablation of traces of the biofouling process are discussed

Surface properties of the skin of dolphins

Summary. In delphinids small biofoulers are potentially challenged to high shear water flow and liquid-vapor interfaces of air bubbles during jumping. In the present study we investigated the skin of the pilot whale, Globicephala melas, with emphasis on topological, biochemical and rheological properties of the skin surface enhancing the efficiency of self-cleaning based on the common behaviour of dolphins.The surface properties were characterized combining rheological measurements with cryo-scanning electron microscopy (C-SEM), transmission electron microscopy (TEM), photoelectron spectroscopy (XPS), and enzyme histochemistry.The results obtained show that the skin of the pilot whale exhibited only marginal loads of biofoulers. The skin surface was even and smoothed by a hydrated jelly material alternating with embedded lipidic droplets. The surface topology demonstrated displayed no particular microniches in the size of biofoulers. The jelly material derived from deeper intercellular space between stratum corneum lamellae and was enriched by various hydrolytic enzymes. Unlike the mucoid-based properties of marine fouling polymers, the rheological mesurements revealed the high elasticity in combination with high energy dissipation rates of the jelly material of the dolphin skin assembled from covalently cross-linked aggregates. XPS measurements carried out on deep-frozen skin samples and the bare jelly material showed the presence of free amino groups and lipidic ester groups, which were dominant chemical features of the skin surface.Since cetaceans lack skin glands the protective power of the skin was considered to be based on the biochemical adaptation of the corneocytes. In regard to the higher shear resistance of the jelly material collected from the stratum corneum contrasting to the biophysical properties of mucoid-based biopolymers, we concluded that the gel is not a substitute of mucus, can withstand higher shear regimes and evens the skin surface. The retention of hydrolytic enzymes incorporated within the gel to some extent broadens the self-cleaning abilities of the dolphin integument by degrading non-dolphin biopolymers. Moreover, the hydrolytic enzymes initiate the desquamation process and probably remove contaminations as large as the desquamating cells (50x80 µm). Since the skin surface exhibits less contact area and microniches biofoulers may adhere to or hide within, we argue that biofoulers challenged to air bubbles or high shear water flow during jumping are easily removed from the skin surface. In this connection, the implications to the self-cleaning abilities are discussed, as based on chemical heterogeneity of the amphiphilic skin surface of the pilot whale and the fouling polymers of conditioning films in relation to the hydrophobic liquid-vapor interfaces of air-bubbles and hydrophilic water flow.We thank Dr. D. Bloch and Dr. H.-P. Joensen, University of the Faroe Islands, for their help in specimen collection from legal harvest. This study was supported by a grant of the Deutsche Forschungsgemeinschaft (ME 1755/1-1 and 1-2)