Silencing long non‐coding RNA MEG3 accelerates tibia fraction healing by regulating the Wnt/β‐catenin signalling pathway

As fracture healing is related to gene expression, fracture healing is prospected to be implicated in long non‐coding RNAs (lncRNAs). This study focuses on the effects of epigenetic silencing of long non‐coding RNA maternally expressed gene 3 (lncRNA MEG3) on fracture healing by regulating the Wnt/β‐catenin signalling pathway. Genes expressed in fracture were screened using bioinformatics and the subcellular location of MEG3 was determined using FISH. Next, we successfully established tibia fracture (TF) models of C57BL/6J and Col2a1‐ICAT mice and the effect of silencing lncRNA MEG3 on fracture healing was detected after TF mice were treated with phosphate buffer saline (PBS), MEG3 siRNA and scramble siRNA. X‐ray imaging, Safranin‐O/fast green and haematoxylin‐eosin (HE) staining and histomorphometrical and biomechanical analysis were adopted to observe and to detect the fracture healing conditions. Additionally, the positive expression of collagen II and osteocalcin was examined using immunohistochemistry. At last, in the in vitro experiment, the relationship of MEG3 and the Wnt/β‐catenin signalling pathway in fraction healing was investigated. MEG3 was located in the cell nucleus. In addition, it was found that MEG3 and the Wnt/β‐catenin signalling pathway were associated with fraction healing. Moreover, silencing MEG3 was proved to elevate callus area and maximum bending load and to furthermore enhance the recanalization of bone marrow cavity. Finally, MEG3 knockdown elevated levels of Col10a1, Runx2, Osterix, Osteocalcin, Wnt10b and β‐catenin/β‐catenin whereas it reduced p‐GSK‐3β/GSK‐3β levels. Taken together, our data supported that epigenetic silencing of lncRNA MEG3 could promote the tibia fracture healing by activating the Wnt/β‐catenin signalling pathway.     

Hyper-adhesion: A Unique Property of Desmosomes

Abstract

Hyper-adhesion is a unique, strongly adhesive form of desmosomal adhesion that functions to maintain tissue integrity. In this short review, we define hyper-adhesion, summarise the evidence for it in culture and in vivo, discuss its role in development, wound healing, and skin disease, and speculate about its molecular and cellular basis.     

Skin wound healing in different aged Xenopus laevis

Xenopus froglets can perfectly heal skin wounds without scarring. To explore whether this capacity is maintained as development proceeds, we examined the cellular responses during the repair of skin injury in 8‐ and 15‐month‐old Xenopus laevis. The morphology and sequence of healing phases (i.e., inflammation, new tissue formation, and remodeling) were independent of age, while the timing was delayed in older frogs. At the beginning of postinjury, wound re‐epithelialization occurred in form of a thin epithelium followed by a multilayered epidermis containing cells with apoptotic patterns and keratinocytes stained by anti‐inducible nitric oxide synthase (iNOS) antibody. The inflammatory response, early activated by recruitment of blood cells immunoreactive to anti‐tumor necrosis factor (TNF)‐α, iNOS, transforming growth factor (TGF)‐β1, and matrix metalloproteinase (MMP)‐9, persisted over time. The dermis repaired by a granulation tissue with extensive angiogenesis, inflammatory cells, fibroblasts, and anti‐α‐SMA positive myofibroblasts. As the healing progressed, wounded areas displayed vascular regression, decrease in cellularity, and rearrangement of provisional matrix. The epidermis restored to a prewound morphology while granulation tissue was replaced by a fibrous tissue in a scar‐like pattern. The quantitative PCR analysis demonstrated an up‐regulated expression of Xenopus suppressor of cytokine signaling 3 (XSOCS-3) and Xenopus transforming growth factor-β2 (XTGF-β2) soon after wounding and peak levels were detected when granulation tissue was well developed with a large number of inflammatory cells. The findings indicate that X. laevis skin wound healing occurred by a combination of regeneration (in epidermis) and repair (in dermis) and, in contrast to froglet scarless wound healing, the growth to a more mature adult stage is associated with a decrease in regenerative capacity with scar‐like tissue formation. J. Morphol. 274:956–964, 2013. © 2013 Wiley Periodicals, Inc.     

Antimicrobial and wound healing activities of certain Sudanese medicinal plants

The emergence of drug-resistant organisms have been increasing globally; therefore, it is a burning need to find an alternative drug to get rid of the diseases caused by resistant strains. This study aims to evaluate the antimicrobial and wound healing activities of Loranthus acacia, Cassia obtusifolia and Cymbopogon proximus plants. All the plants were collected and extracted — by maceration method. Antimicrobial activities determined using standard ATCC strain for Gram-positive bacteria (Bacillus subtilis, Bacillus crew, Methicillin-resistant Staphylococcus aureus, Staphylococcus aureus) and Gram-negative bacteria (Shigella sonnnei, Salmonella Typhimurium, Salmonella typhi, Klebsiella pnuemoniae, Escherichia coli and Pseudomonas aeruginosa) following agar well diffusion method. Plants extracts were prepared as gel and investigated for in vivo wound healing activities in rats. Histological studies were performed on animals’ skin. The results showed that all tested plants have various antimicrobial and wound healing activities. Out of these plants, L. acacia exhibited the best result; it revealed a significant result for antimicrobial activities counter to all Gram-positive, Gram-negative bacteria and wound healing activities in comparing with the reference drug. Thus, it is essential to consider L. acacia as a prospective source in progress in the synthesis of a new antimicrobial drug for the treatment of infectious diseases.     

Comprehensive Chromosome End Remodeling during Programmed DNA Elimination

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夜温对番茄套管嫁接苗愈合的影响

以番茄砧木品种‘桂砧1号’和接穗品种‘中杂105’为试材,采用显微观察等方法研究了26℃昼温条件下,不同夜温(16℃、21℃、26℃)对番茄套管嫁接苗愈合速率及质量的影响。结果表明:(1)随着夜温的升高,嫁接苗接合部愈伤组织细胞增多,接合部直径增大;夜温26℃,嫁接后前5d愈伤组织细胞较多,与夜温16℃相比嫁接苗接合部直径提高了9.7%。(2)随着夜温的降低,嫁接苗接合部维管束连接及愈合进程加快,夜温16℃处理嫁接后第6天维管束已连接,较夜温21℃、26℃处理分别提前3d、6d,而且在第9天隔离层完全消失,较夜温21℃、26℃处理提前3d。(3)随着夜温的降低,嫁接苗木质部输导能力和砧/穗接合力提高,愈合质量提高;夜温16℃处理嫁接苗木质部输导能力比夜温21℃处理提高了12%~24%,砧/穗接合力提高了20%;同时也比夜温26℃处理嫁接成活率提高,木质部输导能力提高了19%~32%,砧/穗接合力提高了28%;根系长度、体积及平均直径也显著增加。可见,在昼温26℃的情况下,夜温16℃最有利于番茄嫁接苗的愈合,形成成活率高、质量优的壮苗。     

The roles of αV integrins in lens EMT and posterior capsular opacification

Posterior capsular opacification (PCO) is the major complication arising after cataract treatment. PCO occurs when the lens epithelial cells remaining following surgery (LCs) undergo a wound healing response producing a mixture of α‐smooth muscle actin (α‐SMA)‐expressing myofibroblasts and lens fibre cells, which impair vision. Prior investigations have proposed that integrins play a central role in PCO and we found that, in a mouse fibre cell removal model of cataract surgery, expression of α_V integrin and its interacting β‐subunits β1, β5, β6, β8 are up‐regulated concomitant with α‐SMA in LCs following surgery. To test the hypothesis that α_V integrins are functionally important in PCO pathogenesis, we created mice lacking the α_V integrin subunit in all lens cells. Adult lenses lacking α_V integrins are transparent and show no apparent morphological abnormalities when compared with control lenses. However, following surgical fibre cell removal, the LCs in control eyes increased cell proliferation, and up‐regulated the expression of α‐SMA, β1‐integrin, fibronectin, tenascin‐C and transforming growth factor beta (TGF‐β)–induced protein within 48 hrs, while LCs lacking α_V integrins exhibited much less cell proliferation and little to no up‐regulation of any of the fibrotic markers tested. This effect appears to result from the known roles of α_V integrins in latent TGF‐β activation as α_V integrin null lenses do not exhibit detectable SMAD‐3 phosphorylation after surgery, while this occurs robustly in control lenses, consistent with the known roles for TGF‐β in fibrotic PCO. These data suggest that therapeutics antagonizing α_V integrin function could be used to prevent fibrotic PCO following cataract surgery.