Modulation of bone marrow mesenchymal stem cell secretome by ECM-like hydrogels

It has been demonstrated that bone marrow mesenchymal stem cell (BM-MSCs) transplantation has beneficial effects on several central nervous system (CNS) debilitating conditions. Growing evidence indicate that trophic factors secreted by these cells are the key mechanism by which they are acting. These cells are frequently used in combination with 3D artificial matrices, for instance hydrogels, in tissue engineering-based approaches. However, so far, no study has been reported on the influence of such matrices, namely the presence or absence of extracellular matrix motifs, on BM-MSCs secretome and its effects in neuronal cell populations. In this sense, we herein studied the impact of a hydrogel, gellan gum, on the behavior and secretome of BM-MSCs, both in its commercial available form (commonly used in tissue engineering) and in a fibronectin peptide-modified form. The results showed that in the presence of a peptide in the gellan gum hydrogel, BM-MSCs presented higher proliferation and metabolic activity than in the regular hydrogel. Moreover, the typical spindle shape morphology of BM-MSCs was only observed in the modified hydrogel. The effects of the secretome of BM-MSCs were also affected by the chemical nature of the extracellular matrix. BM-MSCs cultured in the modified hydrogel were able to secrete factors that induced higher metabolic viabilities and neuronal cell densities, when compared to those of the unmodified hydrogel. Thus adding a peptide sequence to the gellan gum had a significant effect on the morphology, activity, proliferation and secretome of BM-MSCs. These results highlight the importance of mimicking the extracellular matrix when BM-MSCs are cultured in hydrogels for CNS applications.     

Effect of luteinizing hormone/choriogonadotropin receptor (LHCGR) gene on chicken reproductive traits

Luteinizing hormone/choriogonadotropin receptor (LHCGR) gene, potentially related to reproductive traits in chickens, was genotyped by using the Pooled DNA Sequencing, PCR–SSCP and Directing Sequencing techniques. 306 Erlang Mountain chickens form one line (SD03, a line that has been selected for egg quality from a local chicken breed in Sichuan province, China) were genotyped in this study. The associations between LHCGR polymorphisms and six reproductive traits [body weight at first egg (BWAFE), weight of first egg, age at first egg (AFE), number of eggs at 300 days of age (EN), body weight at 300 days of age and egg weight at 300 days of age (EWTA)] were estimated using the one-way analysis of variance method. Results showed that SNP +G4058A and SNP +T4099G of the LHCGR gene were significantly associated with BWFE and AFE. Birds with the AG genotype for the +G4058A SNP exhibited shorter AFE (P < 0.05) and greater EN than those of the GG and AA genotypes, suggesting a balancing selection (overdominance); the effect of allele C in SNP +C3021T and allele C in SNP +T4490C on EN and AFE is additive and may reflect the influence of positive selection. These alleles have promise as genetic markers for future marker-assisted selection.     

Generalized Subcutaneous Phaeohyphomycosis Caused by Phialophora verrucosa: Report of a Case and Review of Literature

We report a case of subcutaneous phaeohyphomycosis due to Phialophora verrucosa in a 64-year-old Chinese farmer suffering from CD4+ lymphopenia. He presented with diffuse and infiltrated plaques involving the entire face including the eyes, neck, occiput, and extending to the dorsal regions of his torso. The patient is notable for the discrete multifocal nature of the illness in the absence of disseminated infection and rarity of P. verrucosa as a cause of subcutaneous phaeohyphomycosis.     

Expression of antimicrobial peptides thanatin(S) in transgenic Arabidopsis enhanced resistance to phytopathogenic fungi and bacteria

Thanatin(S) is an analog of thanatin, an insect antimicrobial peptide possessing strong and broad spectrum of antimicrobial activity. In order to investigate if the thanatin could be used in engineering transgenic plants for increased resistance against phytopathogens, the synthetic thanatin(S) was introduced into Arabidopsis thaliana plants. To increase the expression level of thanatin(S) in plants, the coding sequence was optimized by plant-preference codon. To avoid cellular protease degradation, signal peptide of rice Cht1 was fused to N terminal of thanatin(S) for secreting the expressed thanatin(S) into intercellular spaces. To evaluate the application value of thanatin(S) in plant disease control, the synthesized coding sequence of Cht1 signal peptide (Cht1SP)-thanatin(S) was ligated to plant gateway destination binary vectors pGWB11 (with FLAG tag). Meanwhile, in order to observe the subcellular localization of Cht1SP-thanatin(S)-GFP and thanatin(S)-GFP, the sequences of Cht1SP-thanatin(S) and thanatin(S) were respectively linked to pGWB5 (with GFP tag). The constructs were transformed into Arabidopsis ecotype Col-0 and mutant pad4-1 via Agrobacterium-mediated transformation. The transformants with Cht1SP-thanatin(S)-FLAG fusion gene were analyzed by genomic PCR, real-time PCR, and western blots and the transgenic Arabidopsis plants introduced respectively Cht1SP-thanatin(S)-GFP and thanatin(S)-GFP were observed by confocal microscopy. Transgenic plants expressing Cht1SP-thanatin(S)-FLAG fusion protein showed antifungal activity against Botrytis cinerea and powdery mildew, as well as antibacterial activity against Pseudomonas syringae pv. tomato. And the results from confocal observation showed that the GFP signal from Cht1SP-thanatin(S)-GFP transgenic Arabidopsis plants occurred mainly in intercellular space, while that from thanatin(S)-GFP transgenic plants was mainly detected in the cytoplasm and that from empty vector transgenic plants was distributed uniformly throughout the cell, demonstrating that Cht1 signal peptide functioned. In addition, thanatin(S) and thanatin(S)-FLAG chemically synthesized have both in vitro antimicrobial activities against P. syringae pv. tomato and B. cinerea. So, thanatin(S) is an ideal candidate AMPs for the construction of transgenic crops endowed with a broad-spectrum resistance to phytopathogens and the strategy is feasible to link a signal peptide to the target gene.     

The association between glycogen synthase kinase 3 beta polymorphisms and Parkinson's disease susceptibility: A meta-analysis

Previous studies on the association between glycogen synthase kinase 3 beta (GSK3-β) polymorphisms (rs334558 and rs6438552) and Parkinson's disease (PD) susceptibility remained inconsistent. Thus, the goal of this study was to re-examine their exact association by a meta-analysis. All eligible studies were identified by a systematic literature search of multiple databases. Six studies (3105 cases and 4387 controls) on rs334558 and six studies (2579 cases and 4091 controls) on rs6438552 were included. The quality of these studies was generally good according to the Newcastle–Ottawa Scale (NOS). The meta-analysis showed null association between the two variants and PD susceptibility in all genetic models from the overall or Caucasian population. However, the analysis of rs334558 revealed that the risk of PD decreased in heterozygote, dominant or additive models (OR = 0.60, 95% CI: 0.48, 0.74; OR = 0.63, 95% CI: 0.51, 0.78; OR = 0.82, 95% CI: 0.71, 0.94, respectively) from the Eastern Asian population. Moreover, the analysis on the homozygote, heterozygote, dominant or additive models suggested that rs6438552 also reduced the PD risk (OR = 0.45, 95% CI: 0.24, 0.84; OR = 0.62, 95% CI: 0.39, 0.97; OR = 0.57, 95% CI: 0.37, 0.87; OR = 0.66, 95% CI: 0.49, 0.88, respectively) in the Eastern Asian population. Together, the findings suggest that the two variants both reduced the risk of PD in the Eastern Asian subgroup but not in the overall and Caucasian populations, which should be cautiously interpreted because of limited number of included studies.     

Fibronectin‐binding protein,FbpA, is the adhesin responsible for pathogenesis of Listeria monocytogenes infection

The role of fibronectin binding protein A (FbpA) in Listeria monocytogenes infection and its pathogenesis were studied in vivo and in vitro by constructing a fbpA‐deficient mutant of L. monocytogenes (ΔfbpA). In vivo, ΔfbpA was less pathogenic in mutant mice than was wild‐type L. monocytogenes. FbpA did not affect the amounts of various virulence‐determining factors, including internalin B and listeriolysin O. However, adherence to, and invasion of, mouse hepatocytes by the ΔfbpA mutant were reduced. In contrast, adherence to, but not invasion of, the ΔfbpA mutant to macrophages was attenuated. Fibronectin contributed to the efficient adherence and invasion of wild‐type L. monocytogenes, but not to those of the ΔfbpA mutant. Attenuation of adhesion and uptake of the ΔfbpA mutant were reversed by overexpression of FbpA in it. FbpA was not involved in intracellular growth, autophagy induction or actin tail formation. Thus, the present findings clearly show that FbpA acts as an important adhesion molecule of L. monocytogenes, especially regarding hepatocytes, without modulating the expression of other virulence factors that have been implicated in the pathogenesis of L. monocytogenes infection.