Myelinating glia differentiation is regulated by extracellular matrix elasticity

The mechanical properties of living tissues have a significant impact on cell differentiation, but remain unexplored in the context of myelin formation and repair. In the PNS, the extracellular matrix (ECM) incorporates a basal lamina significantly denser than the loosely organized CNS matrix. Inhibition of non-muscle myosin II (NMII) enhances central but impairs peripheral myelination and NMII has been implicated in cellular responses to changes in the elasticity of the ECM. To directly evaluate whether mechanotransduction plays a role in glial cell differentiation, we cultured Schwann cells (SC) and oligodendrocytes (OL) on matrices of variable elastic modulus, mimicking either their native environment or conditions found in injured tissue. We found that a rigid, lesion-like matrix inhibited branching and differentiation of OL in NMII-dependent manner. By contrast, SC developed normally in both soft and stiffer matrices. Although SC differentiation was not significantly affected by changes in matrix stiffness alone, we found that expression of Krox-20 was potentiated on rigid matrices at high laminin concentration. These findings are relevant to the design of biomaterials to promote healing and regeneration in both CNS and PNS, via transplantation of glial progenitors or the implantation of tissue scaffolds

Multimodality labeling strategies for the investigation of nanocrystalline cellulose biodistribution in a mouse model of breast cancer

Methods We have developed a nuclear and fluorescence labeling strategy for nanocrystalline cellulose (CNC), an emerging biomaterial with versatile chemistry and facile preparation from renewable sources. We modified CNC through 1,1′-carbonyldiimidazole (CDI) activation with radiometal chelators desferrioxamine B and 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA), allowing for the labeling with zirconium-89 (t½ = 78.41 h) and copper-64 (t½ = 12.70 h), respectively, for non-invasive positron emission tomography (PET) imaging. The far-red fluorescent dye Cy5 was added for ex vivo optical imaging, microscopy and flow cytometry. The multimodal CNC were evaluated in the syngeneic orthotopic 4T1 tumor model of human stage IV breast cancer. Results Modified CNC exhibited low cytotoxicity in RAW 264.7 macrophages over 96 h, and high radiolabel stability in vitro. After systemic administration, radiolabeled CNC were rapidly sequestered to the organs of the reticulo-endothelial system (RES), indicating immune recognition and no passive tumor targeting by the enhanced permeability and retention (EPR) effect. Modification with NOTA was a more favorable strategy in terms of radiolabeling yield, specific radioactivity, and both the radiolabel and dispersion stability in physiological conditions. Flow cytometry analysis of Cy5-positive immune cells from the spleen and tumor corroborated the uptake of CNC to phagocytic cells. Conclusions Future studies on the in vivo behavior of CNC should be concentrated on improving the nanomaterial stability and circulation half-life under physiological conditions and optimizing further the labeling yields for the multimodality imaging strategy presented. Advances in knowledge Our studies constitute one of the first accounts of a multimodality nuclear and fluorescent probe for the evaluation of CNC biodistribution in vivo and outline the pitfalls in radiometal labeling strategies for future evaluation of targeted CNC-based drug delivery systems. Implications for patient care Quantitative and sensitive molecular imaging methods provide information on the structure–activity relationships of the nanomaterial and guide the translation from in vitro models to clinically relevant animal models.Peer reviewe

Periodontal Regeneration of Intrabony Defects in Animal Models Using Biologic Modifiers: A Systematic Review and Meta-analysis

Background and purpose: The ultimate goal in periodontal treatment is to achieve a functional and anatomical regeneration of lost tissues. Due to the promising outcomes of biologic modifiers in regenerative therapies, this systematic review aimed at evaluating the effects of various biologic modifiers used in intra-bony osseous defects in animal models. Materials and methods: Electronic databases were searched for articles published in March 2010-March 2020 that had evaluated the effect of bio-modifiers used in periodontal intra-bony osseous defects in animal models. Screening was performed based on inclusion/exclusion criteria and SYRCLE tool was used for studies’ quality assessment. Results: After screening the titles, abstracts, and full-texts, 18 studies were included in qualitative analysis and five studies entered the meta-analysis. According to the configuration of osseous defects, the studies were categorized into three subgroups. Based on histological findings, all these biologic markers significantly enhanced new bone and cementum formation compared to control groups (P<0.001). The meta-analysis showed that biologic modifiers could significantly increase bone regeneration (1.58 mm, 95% CI: 1.12-2.03, P˂0.001) and cementum regeneration (1.27 mm, 95% CI: 0.84-1.70, P˂0.001) in one-wall osseous defects. Conclusion: Biologic modifiers namely growth factors could positively affect periodontal regeneration, particularly the cementum and bone in animal models. Further human studies are necessary to address the clinical use of these biomaterials

Double-stranded DNA in exosomes: a novel biomarker in cancer detection.

We thank Dr Cyrus Ghajar (Fred Hutchinson Cancer Research Center, Seattle) and members from Dr Bromberg's laboratory (Drs Paul Gao, Qing Chang and Ninhui Mao) for sharing reagents. We thank members of the Genomics Resource Core Facility at WCMC for their high quality service and consultation. We thank Tyler Jacks (Koch Institute for Integrative Cancer Research at MIT) for providing pEGFP-N1-p53 plasmid. We also thank members of our laboratories for helpful discussion. We apologize to colleagues whose work could not be cited due to space constraints. Our work is supported by grants from National Cancer Institute (U01-CA169538, DL), National Institutes of Health (R01-CA169416-01, DL and HP), United States Department of Defense (BC123187P2 (DL), W81XWH-13-1-0425 (DL), W81XWH-12-BCRP-IDEA (DL and JB)), Melanoma Research Alliance (HP), Sohn Conference Foundation (HP), the Children's Cancer and Blood Foundation (HP and DL), The Manning Foundation (DL), The Hartwell Foundation (DL), Champalimaud Foundation (HP and DL), Fundacao para a Ciencia e a Tecnologia (DL), The Nancy C and Daniel P Paduano Foundation (HP and DL), The Mary Kay Foundation (DL), Jose Carreras Leukaemia Foundation (DJCLS R12/06, BKT and KW), Pediatric Oncology Experimental Therapeutic Investigator Consortium (POETIC, DL and HP), James Paduano Foundation (DL and HP), Beth Tortolani Foundation (DL and JB), Malcolm Hewitt Weiner Foundation (DL), Theodore A Rapp Foundation (DL), American Hellenic Educational Progressive Association 5th District Cancer Research Foundation (DL), Charles and Marjorie Holloway Foundation (JB), Sussman Family Fund (JB), Lerner Foundation (JB), Breast Cancer Alliance (JB), and Manhasset Women's Coalition Against Breast Cancer (JB).S

Identification of distinct nanoparticles and subsets of extracellular vesicles by asymmetric flow field-flow fractionation

The heterogeneity of exosomal populations has hindered our understanding of their biogenesis, molecular composition, biodistribution and functions. By employing asymmetric flow field-flow fractionation (AF4), we identified two exosome subpopulations (large exosome vesicles, Exo-L, 90-120 nm; small exosome vesicles, Exo-S, 60-80 nm) and discovered an abundant population of non-membranous nanoparticles termed 'exomeres' (~35 nm). Exomere proteomic profiling revealed an enrichment in metabolic enzymes and hypoxia, microtubule and coagulation proteins as well as specific pathways, such as glycolysis and mTOR signalling. Exo-S and Exo-L contained proteins involved in endosomal function and secretion pathways, and mitotic spindle and IL-2/STAT5 signalling pathways, respectively. Exo-S, Exo-L and exomeres each had unique N-glycosylation, protein, lipid, DNA and RNA profiles and biophysical properties. These three nanoparticle subsets demonstrated diverse organ biodistribution patterns, suggesting distinct biological functions. This study demonstrates that AF4 can serve as an improved analytical tool for isolating extracellular vesicles and addressing the complexities of heterogeneous nanoparticle subpopulations.The authors also acknowledge the Genomics Resource Core facility (WCM) for their high-quality service. The authors thank C. Ghajar and J. Weiss for feedback on the manuscript and members of the Lyden laboratory for discussions. Our study was supported by the National Cancer Institute (U01-CA169538 to D.L.), the National Institutes of Health (NIH; R01-CA169416 to D.L. and H.P.; R01-CA218513 to D.L. and H.Z.), the US Department of Defense (W81XWH-13-10249 to D.L.), W81XWH-13-1-0425 (to D.L., J.Br.), the Sohn Conference Foundation (D.L., I.M., H.P. and H.Z.), the Children’s Cancer and Blood Foundation (D.L.), The Manning Foundation (A.H. and D.L.), The Hartwell Foundation (D.L.), The Nancy C. and Daniel P. Paduano Foundation (D.L.), The Starr Cancer Consortium (H.P. and D.L.; D.L. and H.Z.), the Pediatric Oncology Experimental Therapeutic Investigator Consortium (POETIC; D.L.), the James Paduano Foundation (D.L. and H.P.), the NIH/WCM CTSC (NIH/NCATS: UL1TR00457 to H.M. and H.Z.; UL1TR002384 to D.L., H.M. and H.Z.), the Malcolm Hewitt Wiener Foundation (D.L.), the Champalimaud Foundation (D.L.), the Thompson Family Foundation (D.L., R.S.), U01-CA210240 (D.L.), the Beth Tortolani Foundation (J.Br.), the Charles and Marjorie Holloway Foundation (J.Br.), the Sussman Family Fund (J.Br.), the Lerner Foundation (J.Br.), the Breast Cancer Alliance (J.Br.), the Manhasset Women’s Coalition Against Breast Cancer (J.Br.), the National Institute on Minority Health and Health Disparities (NIMHD) of the NIH (MD007599 to H.M.), NIH/NCATS (UL1TR00457 to H.M.). C.R., A.M., D.F., A.F., A.S. and H.O. acknowledge FEDER (Fundo Europeu de Desenvolvimento Regional funds through COMPETE 2020) POCI, Portugal 2020 (NORTE-01-0145-FEDER-000029) and FCT – Fundação para a Ciência e a Tecnologia in the framework of the project ‘Institute for Research and Innovation in Health Sciences’ (POCI-01-0145-FEDER-007274) and the FCT project POCI-01-0145-FEDER-016585 (PTDC/BBB-EBI/0567/2014). The authors acknowledge FCT for grants to A.M. (SFRH/BPD/75871/2011) and A.F. (SFRH/BPD/111048/2015). D.F. acknowledges FCT (SFRH/BD/110636/2015), the BiotechHealth PhD Programme (PD/0016/2012) and the American Portuguese Biomedical Research Fund.S