MicroRNA-129-5p Inhibited C2C12 Myogenesis and Repressed Slow Fiber Gene Expression in vitro

The miR-129 family is widely reported as tumor repressors, while, their roles in skeletal muscle have not been fully investigated. Here, the function and mechanism of miR-129-5p in skeletal muscle, a member of the miR-129 family, were explored using C2C12 cell line. Our study shown that miR-129-5p was widely detected in mouse tissues, with the highest expression in skeletal muscle. Gain- and loss-of-function study shown that miR-129-5p could negatively regulate myogenic differentiation, indicated by reduced ratio of MyHC-positive myofibers and repressed expression of myogenic genes, such as MyoD, MyoG and MyHC. Furthermore, miR-129-5p was more enriched in fast extensor digitalis lateralis (EDL) than in slow soleus (SOL). Enhanced miR-129-5p could significantly reduce the expression of mitochondrial cox family, together with that of MyHC I, and knockdown of miR-129-5p conversely increased the expression of cox genes and MyHC I. Mechanistically, miR-129-5p directly targeted the 3'-UTR of Mef2a, which was suppressed by miR-129-5p agomir at both mRNA and protein levels in C2C12 cells. Moreover, overexpression of Mef2a could rescue the inhibitory effects of miR-129-5p on the expression of myogenic factors and MyHC I. Collectively, our data revealed that miR-129-5p as a negative regulator of myogenic differentiation and slow fiber gene expression, thus affecting body metabolic homeostasis.

Targeting of Mammalian Glycans Enhances Phage Predation in the Gastrointestinal Tract

The human mucosal surface consists of a eukaryotic epithelium, a prokaryotic microbiota, and a carbohydrate-rich interface that separates them. Bacteriophage parasitize the prokaryotes but are not known to associate with eukaryotic cells. In the gastrointestinal tract, the interaction of these two domains influences the health of the host, especially colonization with invasive pathobionts. Antibiotics may be used but they also kill protective commensals and lack the physio-chemical properties to be specifically and optimally active in this complex milieu. Here, we report a novel phage whose lytic cycle is enhanced in intestinal environments. The enhanced activity is encoded in its tail fiber gene, whose protein product binds human heparan sulfated proteoglycans and localizes the phage to the epithelial cell surface, thereby positioning it near its bacterial host, a type of locational targeting mechanism. This finding offers the prospect of developing epithelial-targeting phage to selectively remove invasive pathobiont species from mucosal surfaces.Graphical AbstractModel showing (1) mucins from the intestinal mucus layer inhibit phage infection, (2) phage ES17 can bind to mucin and utilize other intestinal glycans as a receptor to infect and kill mucus-coated bacteria, and (3) phages like ES17 can be utilized to coat the intestinal epithelium by binding heparan sulfate glycans to protect from invasive pathogen infection.

Etv transcription factors functionally diverge from their upstream FGF signaling in lens development

The signal regulated transcription factors (SRTFs) control the ultimate transcriptional output of signaling pathways. Here, we examined a family of FGF-induced SRTFs – Etv1, Etv 4, and Etv 5 – in murine lens development. Contrary to FGF receptor mutants that displayed loss of ERK signaling and defective cell differentiation, Etv deficiency augmented ERK phosphorylation without disrupting the normal lens fiber gene expression. Instead, the transitional zone for lens differentiation was shifted anteriorly as a result of reduced Jag1-Notch signaling. We also showed that Etv proteins suppresses mTOR activity by promoting Tsc2 expression, which is necessary for the nuclei clearance in mature lens. These results revealed the functional divergence between Etv and FGF in lens development, demonstrating that these SRTFs can operate outside the confine of their upstream signaling.

GENETIC DIVERSITY OF ADENOVIRUSES CIRCULATING AMONG THE MILITARY IN THE NORTH-WEST REGION

The contribution of adenovirus (AV) infections to the overall structure of acute viral respiratory infections among young people of draft age can reach as high as 64.6%. Wide dissemination, the incidence of AV-associated pneumonias and lethal outcomes in the case of some complicated infections illustrate the urgency of studying the antigenic diversity of AVs circulating among the military. 991 nasopharyngeal swabs from patients hospitalized in military health facilities with symptoms of acute respiratory infections from 2014 to 2017 were detected by real-time PCR. Sanger sequencing was performed using forward and reverse primers matching the fiber gene. AVs were detected in 326 samples. In 80 of those, AVs were present in combination with other respiratory viruses, as follows: 26 with respiratory syncytial viruses (RSV), 49 with rhinoviruses, 2 with bocaviruses, 1 with RSV and rhinovirus, 1 with parainfluenza virus, and 1 with metapneumovirus. 31 samples were sequenced. Thirty AVs belonged to group E (serotype 4), and 1 AV belonged to group B (serotype 7).

Genetic Diversity of Human Adenovirus in Children with Acute Gastroenteritis, Albania, 2013–2015

The objectives of the present study were to assess the occurrence of human adenoviruses (HAdVs) in paediatric patients with gastroenteritis in Albania and to characterize HAdV strains. Faecal specimens from children admitted with acute gastroenteritis to the Paediatric Hospital in Tirana were screened for HAdV, using broad-range primers targeting the hexon gene, in combination with species-specific primers targeting the fiber gene. Phylogenetic analysis was then performed to assess the genetic relationships among the different sequences and between the sequences of the samples and those of the prototype strains. Adenovirus DNA was detected in 33/142 samples (23.2%); 14 belonged to species F (13 HAdV-41 and 1 HAdV-40), 13 to species C (1 HAdV-1, 8 HAdV-2, and 4 HAdV-5), 5 to species B (HAdV-3), and 1 to species A (HAdV-12). Rotavirus coinfection was present in 9/33 (27.2%) positive samples. In the remaining 24 positive samples (12 enteric—F species; 12 nonenteric—A, B, or C species), HAdVs were detected as unique viral pathogens, suggesting that HAdV may be an important cause of diarrhoea in children requiring hospitalization. This is the first study investigating the presence of human adenoviruses (species A–G) as etiologic agents of viral gastroenteritis in children in Albania.