PECAM1+/Sca1+/CD38+ Vascular Cells Transform into Myofibroblast-Like Cells in Skin Wound Repair

Skin injury induces the formation of new blood vessels by activating the vasculature in order to restore tissue homeostasis. Vascular cells may also differentiate into matrix-secreting contractile myofibroblasts to promote wound closure. Here, we characterize a PECAM1⁺/Sca1⁺ vascular cell population in mouse skin, which is highly enriched in wounds at the peak of neoangiogenesis and myofibroblast formation. These cells express endothelial and perivascular markers and present the receptor CD38 on their surface. PECAM1⁺/Sca1⁺/CD38⁺ cells proliferate upon wounding and could give rise to α-SMA⁺ myofibroblast-like cells. CD38 stimulation in immunodeficient mice reduced the wound size at the peak of neoangiogenesis and myofibroblast formation. In humans a corresponding cell population was identified, which was enriched in sprouting vessels of basal cell carcinoma biopsies. The results indicate that PECAM1⁺/Sca1⁺/CD38⁺ vascular cells could proliferate and differentiate into myofibroblast-like cells in wound repair. Moreover, CD38 signaling modulates PECAM1⁺/Sca1⁺/CD38⁺ cell activation in the healing process implying CD38 as a target for anti-angiogenic therapies in human basal cell carcinoma.     

(+)-Usnic acid enamines with remarkable cicatrizing properties

Wound healing is a significant concern in many pathologies (post-surgeries, burns, scars) and the search for new chemical entities is advisable. The lichen compound (+)-usnic acid (1) has found application in dermatological and cosmetic preparations, due to its bacteriostatic and antioxidant activities. The compound has also been shown to stimulate the wound closure of keratinocyte monolayers at subtoxic doses. Here we describe the design and synthesis of usnic acid enamines (compounds 2–11), obtained through nucleophilic attack of amino acids or decarboxyamino acids at the acyl carbonyl of the enolized 1,3 diketone. The wound repair properties of these derivatives were evaluated using in vitro and in vivo assays. Compounds 8 and 9 combine low cytotoxicity with high wound healing performance, suggesting their possible use in wound healing-promoting or antiage skin preparations.     

CHEK2 1100delC, IVS2+1G>A and I157T mutations are not present in colorectal cancer cases from Turkish population

BackgroundThe cell cycle checkpoint kinase 2 (CHEK2) protein participates in the DNA damage response in many cell types. Germline mutations in CHEK2 (1100delC, IVS2+1G>A and I157T) have been impaired serine/threonine kinase activity and associated with a range of cancer types. This hospital-based case–control study aimed to investigate whether CHEK2 1100delC, IVS2+1G>A and I157T mutations play an important role in the development of colorectal cancer (CRC) in Turkish population.MethodsA total of 210 CRC cases and 446 cancer-free controls were genotyped for CHEK2 mutations by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific-polymerase chain reaction (AS-PCR) methods.ResultsWe did not find the CHEK2 1100delC, IVS2+1G>A and I157T mutations in any of the Turkish subjects.ConclusionOur result demonstrate for the first time that CHEK2 1100delC, IVS2+1G>A and I157T mutations have not been agenetic susceptibility factor for CRC in the Turkish population. Overall, our data suggest that genotyping of CHEK2 mutations in clinical settings in the Turkish population should not be recommended. However, independent studies are need to validate our findings in a larger series, as well as in patients of different ethnic origins.     

Production of L-DOPA and dopamine in recombinant bacteria bearing the Vitreoscilla hemoglobin gene

Given the well-established beneficial effects of Vitreoscilla hemoglobin (VHb) on heterologous organisms, the potential of this protein for the production of L -DOPA and dopamine in two bacteria, Citrobacter freundii and Erwinia herbicola, was investigated. The constructed recombinants bearing the VHb gene (vgb⁺) had substantially higher levels of cytoplasmic L -DOPA (112 mg/L for C. freundii and 97 mg/L for E. herbicola) than their respective hosts (30.4 and 33.8 mg/L) and the vgb^– control strains (35.6 and 35.8 mg/L). Further, the vgb⁺ recombinants of C. freundii and E. herbicola had 20-fold and about two orders of magnitude higher dopamine levels than their hosts, repectively. The activity of tyrosine phenol-lyase, the enzyme converting L -tyrosine to L -DOPA, was well-correlated to cytoplasmic L -DOPA levels. As cultures aged, higher tyrosine phenol-lyase activity of the vgb⁺ strains was more apparent.     

Characterization of the cellular response during apoptosis induction in cadmium-treated hep G2 human hepatoma cells

Cadmium is a toxic transition heavy metal of continuing occupational and environmental concern, with a wide variety of adverse effects on regulation of gene expression and cellular signal transduction pathways. Injury to cells by cadmium leads to a complex series of events that can culminate in the death of the cell. It has been reported that cadmium induces apoptosis in many cell lines. However, the morphological characteristics leading to apoptosis or subsequent regeneration in cells exposed to cadmium have not been clarified. We evaluated whether human hepatoma cells maintained in culture undergo apoptosis when exposed to cadmium. Cytotoxic activity of cadmium on Hep G2 cells determined using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. A DNA ladder assay was performed by electrophoresis. Cell cycle analysis was quantified by flow cytometry. Nuclear morphology was studied by fluorescence microscopy after staining with propidium iodide and Hoechst 33342. Morphologic alterations in culture hepatocytes treated with CdCl₂ were observed by transmission electron microscopy. We have demonstrated that apoptosis is a major mode of elimination of damaged HepG2 cells in cadmium toxicity and it precedes necrosis.     

Polystoma macrocnemis n. sp. (Monogenea: Polystomatidae) from the Iranian longlegged wood frog Rana macrocnemis (Ranidae) in Turkey

Polystoma macrocnemis n. sp. (Polystomatidae) is described from the urinary bladder of Rana macrocnemis (Ranidae) in Turkey. Its general morphology is similar to that of other members of the genus, but it is distinguished from closely related species by numerical parameters of the hamuli and also by its host species and geographical range.     

Biochemical and morphological characteristics of selenite-induced apoptosis in human hepatoma hep G2 cells

Selenium is a cellular growth inhibitor in many mammary tumor cells. To comprehend the mechanism for the selenium-induced cell death, we examined the effects of sodium selenite, which has been one of the most extensively investigated selenium compounds, in human hepatoma Hep G2 cells. Cell viability gradually decreased after treatment with sodium selenite within the concentration range of 10–50 μM. Low (10 μM) selenite has shown a high-percentage laddering pattern compared to the high (25 μM) cytotoxic selenium concentration in agarose gel electrophoresis. G₂M-phase enrichment was also concentration dependent. The most consistent transmission electron microscopic finding was the existence of large lysosomes. Based on these data, we hypothesize that sodium selenite predominantly shows its apoptotic effect over hydrogen selenite accumulation.     

Localization and function of cyclic guanosine monophosphate-phosphodiesterase activity in the retinal rods of the rat by means of a newly developed cytochemical method

Summary Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) activity was studied histo- and cytochemically in the retinal rods of the rat with the use of a newly developed technique. Intense activity of cGMP-PDEase was evenly distributed over the outer segments of the rods. Reaction product was observed on the plasmalemma and on the disk membranes of the outer segments. A weak reaction product occurred also on the plasmalemma of the inner segments; however, no precipitate was found in the perinuclear and synaptic portions of the rod cells. The enzyme activity was strongly inhibited by 2 mM theophilline and by 2 mM 3-isobutyl-1-methylxanthine (IBMX). To confirm the specificity of this new cGMP-PDEase method, the localization of 5nucleotidase (5GMPase) was also studied. In contrast to the activity of cGMP-PDEase, the activity of 5GMPase was distributed on the plasma membrane of the photoreceptor cells extending over a wide range from the synaptic endings in the outer plexiform layer to the tip of the outer segments.     

Ultracytochemical localization of Ca++-ATPase activity in the paraphyseal epithelial cells of the frog,Rana esculenta

Summary Ca⁺⁺-ATPase activity was studied ultracytochemically (cf. Ando et al. 1981) in the paraphysis cerebri of the frog. An intense reaction was demonstrated on the plasmalemma of the microvilli at the apical pole of paraphyseal cells; in contrast, the basolateral plasmalemma showed only a slight staining. In addition, mitochondria, gap junctions, cilia, and cytoplasmic elements (e.g., microfilaments) displayed Ca⁺⁺-ATPase activity. Variation of the Ca⁺⁺-concentration in the incubation medium from 0.1 mM to 100 mM altered the Ca⁺⁺-ATPase activity of the cell organelles. The substitution of Ca-by Mg-ions resulted in a conspicuous decrease in the enzyme activity, especially on the apical plasmalemma. Ca⁺⁺-ATPase activity is claimed to be involved in a number of extra-and intracellular functions. In comparison to the epithelium of the adjacent choroid plexus the paraphyseal epithelial cell is thought to be a principal Ca-ion regulator of the cerebrospinal fluid in frogs.Fellow of the Alexander von Humboldt Foundation     

Evolution of Buchlo? dactyloides based on cloning and sequencing of matK, rbcL, and cob genes from plastid and mitochondrial genomes.

Buffalograss (Buchlo? dactyloides (Nutt.) Englem), a C4 turfgrass species, is native to the Great Plains region of North America. The evolutionary implications of buffalograss are unclear. Sequencing of rbcL and matK genes from plastid and the cob gene from mitochondrial genomes was examined to elucidate buffalo grass evolution. This study is the first to report sequencing of these genes from organelle genomes in the genus Buchlo?. Comparisons of sequence data from the mitochondrial and plastid genome revealed that all genotypes contained the same cytoplasmic origin. There were some rearrangements detected in mitochondrial genome. The buffalograss genome appears to have evolved through the rearrangements of convergent subgenomic domains. Combined analyses of plastid genes suggest that the evolutionary process in Buchlo? accessions studied was monophyletic rather than polyphyletic. However, since plastid and mitochondrial genomes are generally uniparentally inherited, the evolutionary history of these genomes may not reflect the evolutionary history of the organism, especially in a species in which out-crossing is common. The sequence information obtained from this study can be used as a genome-specific marker for investigation of the buffalograss polyploidy complex and testing of the mode of plastid and mitochondrial transmission in genus Buchlo?.