In Vivo Mapping of Eukaryotic RNA Interactomes Reveals Principles of Higher-Order Organization and Regulation.

Identifying pairwise RNA-RNA interactions is key to understanding how RNAs fold and interact with other RNAs inside the cell. We present a high-throughput approach, sequencing of psoralen crosslinked, ligated, and selected hybrids (SPLASH), that maps pairwise RNA interactions in vivo with high sensitivity and specificity, genome-wide. Applying SPLASH to human and yeast transcriptomes revealed the diversity and dynamics of thousands of long-range intra- and intermolecular RNA-RNA interactions. Our analysis highlighted key structural features of RNA classes, including the modular organization of mRNAs, its impact on translation and decay, and the enrichment of long-range interactions in noncoding RNAs. Additionally, intermolecular mRNA interactions were organized into network clusters and were remodeled during cellular differentiation. We also identified hundreds of known and new snoRNA-rRNA binding sites, expanding our knowledge of rRNA biogenesis. These results highlight the underexplored complexity of RNA interactomes and pave the way to better understanding how RNA organization impacts biology.

Suppressor Effects of Sodium Pentaborate Pentahydrate and Pluronic F68 on Adipogenic Differentiation and Fat Accumulation.

Obesity is a major public health problem worldwide and a risk factor for certain diseases, including cardiovascular disease, diabetes, cancer, and depression. Unfortunately, currently available anti-obesity drugs have failed in the long-term maintenance of weight control. It has been a challenge to design novel drugs that could potentially treat obesity or prevent uncontrolled weight-gain which lies underneath the pathology of obesity. Since obesity in a way is a consequence of the accumulating new mature adipocytes from undifferentiated precursors which is a process also termed as adipogenesis, drugs that might control adipogenesis could be beneficial for the treatment of obesity. In the current study, combined effect of sodium pentaborate pentahydrate (NaB) and pluronic F68 on adipogenic differentiation was examined by administering various combinations of the two agents to human adipose-derived stem cells (hADSCs) in in vitro. Immunocytochemistry and quantitative RT-PCR were performed to evaluate the levels of adipogenesis-promoting genes such as peroxisome proliferator-activated receptor-γ (PPARγ), fatty acid binding protein (FABP4), and adiponectin. Results indicated that expressions of all these three genes were restrained. Furthermore, Oil Red O staining revealed that lipid vesicle formation was reduced in hADSCs treated with differentiation medium containing NaB/F68 combination. Finally, expression levels of Hippo pathway kinases Lats2, MST1, and scaffold protein Sav1 were reduced in these cells, suggesting a possible link between Hippo pathway-dependent downregulation of PPARγ and the NaB/F68 treatment. Herein, we showed that combination of NaB and F68 curtails adipocyte differentiation by inhibiting the adipogenic transcriptional program leading to a decrease in lipid accumulation in adipocytes even at very low doses, thereby uncovered a striking opportunity to use this combination in obesity treatment.

Genome-wide identification of natural RNA aptamers in prokaryotes and eukaryotes.

RNAs are well-suited to act as cellular sensors that detect and respond to metabolite changes in the environment, due to their ability to fold into complex structures. Here, we introduce a genome-wide strategy called PARCEL that experimentally identifies RNA aptamers in vitro, in a high-throughput manner. By applying PARCEL to a collection of prokaryotic and eukaryotic organisms, we have revealed 58 new RNA aptamers to three key metabolites, greatly expanding the list of natural RNA aptamers. The newly identified RNA aptamers exhibit significant sequence conservation, are highly structured and show an unexpected prevalence in coding regions. We identified a prokaryotic precursor tmRNA that binds vitamin B2 (FMN) to facilitate its maturation, as well as eukaryotic mRNAs that bind and respond to FMN, suggesting FMN as the second RNA-binding ligand to affect eukaryotic expression. PARCEL results show that RNA-based sensing and gene regulation is more widespread than previously appreciated in different organisms.

Tooth replantation with adipose tissue stem cells and fibrin sealant: microscopic analysis of rat's teeth.

Treatment for dental avulsion cases is early or late replantation of the traumatized teeth. Prognosis of the replanted tooth depends on the level of periodontal injury. Adipose tissue stem cells (ATSCs) were reported to improve periodontal ligament tissue (PDL) regeneration. Fibrin sealant (FS) contains thrombin and fibrinogen to form an adhesive fibrin clot routinely used in surgical procedures. Here, we aimed to investigate the effects of ATSCs + FS treatment on healing of PDL after tooth replantation in a rat model. After 60 min of extraction, maxillary central incisor teeth were replanted with ATSCs + FS. Two months later, the rats were sacrificed and hemimaxilla blocks were dissected out for histological analysis. The results showed that there was a significant improvement in histological findings of ATSCs + FS treated group compared to only FS treated and non-treated groups corresponding to reduced inflammatory resorption and increased new PDL formation. Furthermore, the ankylosis levels were lowered after ATSCs + FS treatment. Singular use of FS improved PDL healing moderately. Our results indicated that ATSCs + FS treatment improves PDL healing after tooth replantation suggesting a new therapeutic potential in the treatment of dental avulsion cases.

Isolation and characterization of dental pulp stem cells from a patient with Papillon-Lefèvre syndrome.

INTRODUCTION: Papillon-Lefèvre syndrome (PLS) is a rare autosomal recessive disorder characterized by immune dysregulation because of a mutation in cathepsin c gene, resulting in hyperkeratosis of the palms, soles, elbows, and knees combined with premature loss of the primary and permanent dentitions. Periodontal tissue abnormalities in PLS patients were reported previously. However, less is known about dental pulp tissue derived cells of PLS patients. This study aimed to show stem cell potential of PLS dental pulp stem cells (DPSCs) and provide new evidence regarding the pathophysiology of the disease. METHODS: DPSCs were characterized by using flow cytometry and immunocytochemistry. They were also induced to differentiate into adipogenic, osteogenic, chondrogenic, odontogenic, and myogenic cells. RESULTS: The results revealed that PLS DPSCs are stained positive for mesenchymal stem cells surface markers CD29, CD73, CD90, CD105, and CD166. PLS DPSCs were able to differentiate into adipogenic, osteogenic, chondrogenic, and odontogenic cell types properly. PLS DPSCs expressed embryonic stem cell markers Oct4, Sox2, cMYc, and Klf4 and showed similar proliferation rate compared with DPSCs isolated from healthy young controls. Interestingly, it was found that unlike the healthy DPSCs, PLS DPSCs are not able to form myotubes with correct morphology. CONCLUSIONS: These data are being reported for the first time; therefore, they might provide new insights to the pathology of the disease. Our results suggest that the PLS DPSCs might be an autologous stem cell source for PLS patients for cellular therapy of alveolar bone defects and other dental tissue abnormalities observed in PLS.