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Purpose: Prevailing evidences have demonstrated that circular RNAs (circRNAs) are closely associated with various stages of carcinogenesis. However, very few studies have delineated the specific mechanism of association between circRNAs and osteosarcoma (OS). It offers a novel insight that circRNAs can be explored as a potential therapeutic strategy for OS., Materials and Methods: In this study, circTUBGCP3 was chosen from the existing reported circRNA microarray data obtained from OS cell lines and normal bone cells. Subsequently, qRT-PCR was performed to evaluate the expression level of circTUBGCP3 in OS samples and cell lines. Functional assays were conducted to estimate the impact of circTUBGCP3 on human OS cells proliferation, vitality, survivability, and migration. Western blot, luciferase reporter and in vivo tumorigenesis assays were performed to analyze the signaling pathways underlying the interaction of circTUBGCP3, miR-30b, and Vimentin., Results: The data indicate that circTUBGCP3 may act as a sponge of miR-30b that further alters the expression of Vimentin, and promotes the proliferation and metastatic properties of OS cells., Conclusion: circTUBGCP3 serves as a tumor promoter in tumorigenesis by increasing the possibilities of OS initiation and proliferation., Competing Interests: The authors report no conflicts of interest in this work., (© 2020 Xu et al.)

Objective: To fulfil an unmet therapeutic need for treating type 2 diabetes by developing an innovative oral drug delivery nanosystem increasing the production of glucagon-like peptide-1 (GLP-1) and the absorption of peptides into the circulation., Design: We developed a nanocarrier for the oral delivery of peptides using lipid-based nanocapsules. We encapsulated the GLP-1 analogue exenatide within nanocapsules and investigated in vitro in human L-cells (NCl-H716) and murine L-cells (GLUTag cells) the ability of the nanosystem to trigger GLP-1 secretion. The therapeutic relevance of the nanosystem in vivo was tested in high-fat diet (HFD)-induced diabetic mice following acute (one administration) or chronic treatment (5 weeks) in obese and diabetic mice., Results: We demonstrated that this innovative nanosystem triggers GLP-1 secretion in both human and murine cells as well as in vivo in mice. This strategy increases the endogenous secretion of GLP-1 and the oral bioavailability of the GLP-1 analogue exenatide (4% bioavailability with our nanosystem).The nanosystem synergizes its own biological effect with the encapsulated GLP-1 analogue leading to a marked improvement of glucose tolerance and insulin resistance (acute and chronic). The chronic treatment decreased diet-induced obesity, fat mass, hepatic steatosis, together with lower infiltration and recruitment of immune cell populations and inflammation., Conclusion: We developed a novel nanosystem compatible with human use that synergizes its own biological effect with the effects of increasing the bioavailability of a GLP-1 analogue. The effects of the formulation were comparable to the results observed for the marketed subcutaneous formulation. This nanocarrier-based strategy represents a novel promising approach for oral peptide delivery in incretin-based diabetes treatment., Competing Interests: Competing interests: PDC is a co-founder of A-Mansia Biotech SA., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.)

Multipotent mesenchymal stromal cells (MMSCs) are promising to treat a variety of traumatic and degenerative diseases. However, in vitro-passage aging induces cell cycle arrest and a series of genetic and biological changes, which greatly limits ex vivo cell number expansion and further clinical application of MMSCs. In most cases, DNA damage and DNA damage response (DDR) act as the main cause and executor of cellular senescence respectively. Mechanistically, DNA damage signals induce cell cycle arrest and DNA damage repair via DDR. If the DNA damage is indelible, MMSCs would entry into a permanent cell cycle arrest. It should be noted that apart from DDR signaling, certain proliferation or metabolism pathways are also occupied in DNA damage related cell cycle arrest. New findings of these aspects will also be summarized in this study. In summary, we aim to provide a comprehensive review of DDR associated cell cycle regulation and other major molecular signaling in the senescence of MMSCs. Above knowledge could contribute to improve the limited capacity of in vitro expansion of MMSCs, and then promote their clinical applications.

L cells are enteroendocrine cells located throughout the gastrointestinal tract that secrete physiologically important peptides. The most characterized peptides secreted by L cells are the peptide YY (PYY) and the glucagon-like peptides 1 (GLP-1) and 2 (GLP-2). These peptides are released rapidly into the circulation after oral nutrient ingestion. Recently, lipid-based nanoparticles (NP) have been described as triggers for GLP-1 secretion by L cells. NP physicochemical properties play a key role in the NP-cell interaction, and drive NP cell internalization. We herein hypothesize that lipid-based NP with appropriate size would not only be able to deliver drugs into blood circulation but also act like endogenous ligands to stimulate GLP-1 secretion. We tested five different size (25, 50, 100, 150, and 200 nm) lipid nanocapsules (LNC) on murine L cells in vitro to confirm this hypothesis. Our study showed that GLP-1 secretion was induced only by the 200 nm size LNC, highlighting the importance of LNC particle size on the secretion of GLP-1 by L cells. The different formulations did not affect proglucagon mRNA expression, suggesting that there was not an increased GLP-1 synthesis. As a proof of concept, we further demonstrated in normoglycemic mice that 200 nm LNC administration increases GLP-1 levels by 4- and 3-fold compared to untreated control mice 60 and 180 min after the administration, respectively. Our study suggests that 200 nm LNC as a nanocarrier to encapsulate drug candidates and as a ligand to induce endogenous GLP-1 secretion might represent a promising strategy for type 2 diabetes mellitus treatment.

The association between PICALM rs3851179 variant and Alzheimer's disease (AD) has been well established by previous genome-wide association studies (GWAS) and candidate gene studies in European population. Recent studies investigated the association between PICALM rs3851179 and AD susceptibility in Chinese population. However, these studies reported consistent and inconsistent results. Here, we selected 9435 samples including 3704 AD cases and 5731 controls from previous studies and evaluated this association using a meta-analysis method for additive model. We did not observe significant genetic heterogeneity in Chinese population. Our results indicate significant association between PICALM rs3851179 and AD in Chinese population. The sensitivity analysis indicates that the association between rs3851179 and AD did not vary substantially. The regression analysis suggests no significant publication bias. In summary, this updated meta-analysis highlights the involvement of PICALM rs3851179 variant in Alzheimer's disease susceptibility in Chinese population.

As for the existence of epithelium barrier, accelerating the transport remains huge challenges for orally delivered protein and peptide drugs into blood circulation. Modifying nanopaticles (NPs) with targeting peptides can enhance the intestinal absorption of loaded macromolecular drugs. However, the transport process, which mainly means how the NPs pass through the apical membrane and the basolateral side and then enter into blood circulation, is needed comprehensive investigation. In this study, we systemically studied the transport mechanisms in Caco-2 cell model of trimethyl chitosan based NPs (TMC NPs) before and after modification of FQS, an integrin αvβ3 receptor targeting peptide. Our results showed FQS peptide mediated multiple endocytosis pathways and could activate integrin αvβ3 receptor by interacting with FAK and Src-family kinases to induce receptor-mediated endocytosis of the NPs. Then, both endocytosed NPs could transport from early endosome to lysososmes via late endosomes/lysosome pathway, as well as to recycling endosomes and Golgi apparatus through early endosome/recycling endosomes and Golgi apparatus/recycling endosomes/plasma membrane pathways, respectively. After FQS peptide modification, the endocytosis subpathways of NPs have been changed, and more pathways are involved in exocytosis process for FQS-modified NPs compared with non-modified NPs. Our study indicated the ligand modification could enhance the uptake and transport by altering some pathways in whole transport process of NPs., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Oral administration of insulin remains a challenge due to its poor enzymatic stability and inefficient permeation across epithelium. We herein developed a novel self-assembled polyelectrolyte complex nanoparticles by coating insulin-loaded dodecylamine-graft-γ-polyglutamic acid micelles with trimethyl chitosan (TMC). The TMC material was also conjugated with a goblet cell-targeting peptide to enhance the affinity of nanoparticles with epithelium. The developed nanoparticle possessed significantly enhanced colloid stability, drug protection ability and ameliorated drug release profile compared with graft copolymer micelles or ionic crosslinked TMC nanoparticles. For in vitro evaluation, Caco-2/HT29-MTX-E12 cell co-cultures, which composed of not only enterocyte-like cells but also mucus-secreting cells and secreted mucus layer, were applied to mimic the epithelium. Intracellular uptake and transcellular permeation of encapsulated drug were greatly enhanced for NPs as compared with free insulin or micelles. Goblet cell-targeting modification further increased the affinity of NPs with epithelium with changed cellular internalization mechanism. The influence of mucus on the cell uptake was also investigated. Ex vivo performed with rat mucosal tissue demonstrated that the nanoparticle could facilitate the permeation of encapsulated insulin across the intestinal epithelium. In vivo study preformed on diabetic rats showed that the orally administered nanoparticles elicited a prolonged hypoglycemic response with relative bioavailability of 7.05%., (Copyright © 2015 Elsevier B.V. All rights reserved.)