Long-term culture of patient-derived cardiac organoids recapitulated Duchenne muscular dystrophy cardiomyopathy and disease progression

Duchenne Muscular Dystrophy (DMD) is an X-linked neuromuscular disease which to date is incurable. The major cause of death is dilated cardiomyopathy however, its pathogenesis is unclear as existing cellular and animal models do not fully recapitulate the human disease phenotypes. In this study, we generated cardiac organoids from patient-derived induced pluripotent stem cells (DMD-COs) and isogenic-corrected controls (DMD-Iso-COs) and studied if DMD-related cardiomyopathy and disease progression occur in the organoids upon long-term culture (up to 93 days). Histological analysis showed that DMD-COs lack initial proliferative capacity, displayed a progressive loss of sarcoglycan localization and high stress in endoplasmic reticulum. Additionally, cardiomyocyte deterioration, fibrosis and aberrant adipogenesis were observed in DMD-COs over time. RNA sequencing analysis confirmed a distinct transcriptomic profile in DMD-COs which was associated with functional enrichment in hypertrophy/dilated cardiomyopathy, arrhythmia, adipogenesis and fibrosis pathways. Moreover, five miRNAs were identified to be crucial in this dysregulated gene network. In conclusion, we generated patient-derived cardiac organoid model that displayed DMD-related cardiomyopathy and disease progression phenotypes in long-term culture. We envision the feasibility to develop a more complex, realistic and reliable in vitro 3D human cardiac-mimics to study DMD-related cardiomyopathies

Guide cells support muscle regeneration and affect neuro-muscular junction organization

Muscular regeneration is a complex biological process that occurs during acute injury and chronic degeneration, implicating several cell types. One of the earliest events of muscle regeneration is the inflammatory response, followed by the activation and differentiation of muscle progenitor cells. However, the process of novel neuromuscular junction formation during muscle regeneration is still largely unexplored. Here, we identify by single-cell RNA sequencing and isolate a subset of vessel-associated cells able to improve myogenic differentiation. We termed them 'guide' cells because of their remarkable ability to improve myogenesis without fusing with the newly formed fibers. In vitro, these cells showed a marked mobility and ability to contact the forming myotubes. We found that these cells are characterized by CD44 and CD34 surface markers and the expression of Ng2 and Ncam2. In addition, in a murine model of acute muscle injury and regeneration, injection of guide cells correlated with increased numbers of newly formed neuromuscular junctions. Thus, we propose that guide cells modulate de novo generation of neuromuscular junctions in regenerating myofibers. Further studies are necessary to investigate the origin of those cells and the extent to which they are required for terminal specification of regenerating myofibers

Study of the effects of different biomaterials on osteogenic differentiation of oral-periosteal cells

Bone regeneration is currently one of the most important challenges for regenerative medicine and it is considered an ideal clinical strategy in the maxillo-facial area [1]. Bone resorption of alveolar crest occurring after tooth extraction leads to several risks for future treatments, including dental implants. For this reason, alveolar ridge preservation (ARP) has become a key component of contemporary clinical dentistry. Several clinical techniques and bone substitute materials can be used to fill the socket after tooth extraction. For all of them, the principle aim is to keep the shape and the size of the bone socket of the extracted tooth allowing inserting the dental implants [2]. The goal of our study was to compare different biocompatible scaffolds based on PLGA (Fisiograft®), Bioglass (Activioss®) and collagen (Sombrero®) in an in vitro model of tissue engineering for dental applications. The cells used in our study derived from Periosteum obtained from four different patients that underwent socket preservation selected by the School of Dentistry of the University of Pavia, previous informed consent. We created bio-complexes constituted by mesenchymal-periosteal cells seeded on different types of biomaterials and we performed adhesion, morphological, proliferative and bone differentiation analyses at different time points (7, 14 and 28 days of culture) in proliferative and osteogenic conditions. Bone differentiation was evaluated by qRT-PCR on genes involved in osteoblast development, like BMP-2, Osteocalcin and Periostin. Our results demonstrated that Sombrero® enhanced adhesion and proliferation of periosteal cells, as highlighted by Haematoxylin-Eosin staining and XTT test (3 and 7 days). Long-term studies (14 and 28 days) demonstrated that periosteal differentiation is about the same among the different materials tested. From these preliminary studies we can conclude that it could be advantageous the clinical use of both collagenic and PLGA scaffolds in order to ameliorate initial colonization and subsequent mechanical support in maxillo-bone regeneration. This work was supported by grant from NATO 2016 (“RAWINTS” (G-984961): RApid Skin Wound healing by INtegrated Tissue engineering and Sensing)

Ethyl Glucuronide Elimination Kinetics in Fingernails and Comparison to Levels in Hair

Measurement of ethyl glucuronide (EtG) in nail, as a biomarker for alcohol intake, has recently been suggested as alternative to measurement in hair. The aim of this study was to compare levels of EtG in nail and hair, and to investigate the elimination kinetics of EtG in fingernails during an alcohol abstinent period

The role of MICAL2 gene in myogenic differentiation

The dystrophin-glycoprotein complex (DGC) is composed of several transmembrane and peripheral components localized in the sarcolemma of skeletal muscle. Mutations in genes that encode DGC components lead to the loss of either expression and/or function of the DGC in muscle. As DGC complex interacts with F-actin it is reasonable that the multidomain F-actin binding protein MICAL2 that transduces semaphorin/plexin external signaling into cytoskeletal modifications, might interact either directly or indirectly with the DGC complex. MICAL2 is indeed expressed in skeletal and cardiac muscles and drosophila Mical mutants reveal that the architecture of contractile muscle filaments is negatively affected. We focus here on the role of MICALs in myogenic differentiation. The rationale to investigate MICAL2 in muscle differentiation is also highlighted in a paper regarding a complex muscle genome-wide expression profiling during the disease evolution in mdx mice, a mouse model of Duchenne muscular dystrophy (1). In this study the authors found MICAL2 among a set of totally ten functionally linked genes involved in the decline of muscle necrosis in mdx mice. For this purpose MICAL2 gain and loss of function studies have been performed in myogenic cell line and compared to in vivo analysis of MICAL2 expressions in acute and chronic muscle degeneration. Recently we showed that that differential myogenic propensity influences the commitment of isogenic induce pluripotent stem cells and a specifically isolated pool of mesodermal iPSC-derived progenitors (MiPs) toward the striated muscle lineages (2). Analysis of MICAL2 expression in MiPs is currently under investigation. Taken together modulation of MICAL2 has an impact on skeletal muscle commitment and could be considered a potential therapeutic target for Duchenne patients. This work was supported with the contribution of “Opening The Future” Campaign [EJJ-OPTFUT-02010] CARIPLO 2015_0634, FWO (#G088715N, #G060612N, #G0A8813N), and IUAP-VII/07 (EJJ-C4851-17/07-P) grants

The role of MICAL2 gene in myogenic differentiation

The dystrophin-glycoprotein complex (DGC) is composed of several transmembrane and peripheral components localized in the sarcolemma of skeletal muscle. Mutations in genes that encode DGC components lead to the loss of either expression and/or function of the DGC in muscle. As DGC complex interacts with F-actin it is reasonable that the multidomain F-actin binding protein MICAL2 that transduces semaphorin/plexin external signaling into cytoskeletal modifications, might interact either directly or indirectly with the DGC complex. MICAL2 is indeed expressed in skeletal and cardiac muscles and drosophila Mical mutants reveal that the architecture of contractile muscle filaments is negatively affected. We focus here on the role of MICALs in myogenic differentiation. The rationale to investigate MICAL2 in muscle differentiation is also highlighted in a paper regarding a complex muscle genome-wide expression profiling during the disease evolution in mdx mice, a mouse model of Duchenne muscular dystrophy (1). In this study the authors found MICAL2 among a set of totally ten functionally linked genes involved in the decline of muscle necrosis in mdx mice. For this purpose MICAL2 gain and loss of function studies have been performed in myogenic cell line and compared to in vivo analysis of MICAL2 expressions in acute and chronic muscle degeneration. Recently we showed that that differential myogenic propensity influences the commitment of isogenic induce pluripotent stem cells and a specifically isolated pool of mesodermal iPSC-derived progenitors (MiPs) toward the striated muscle lineages (2). Analysis of MICAL2 expression in MiPs is currently under investigation. Taken together modulation of MICAL2 has an impact on skeletal muscle commitment and could be considered a potential therapeutic target for Duchenne patients. This work was supported with the contribution of “Opening The Future” Campaign [EJJ-OPTFUT-02010] CARIPLO 2015_0634, FWO (#G088715N, #G060612N, #G0A8813N), and IUAP-VII/07 (EJJ-C4851-17/07-P) grants

Valproic acid stimulates myogenesis in pluripotent stem cell-derived mesodermal progenitors in a NOTCH-dependent manner

Muscular dystrophies are debilitating neuromuscular disorders for which no cure exists. As this disorder affects both cardiac and skeletal muscle, patients would benefit from a cellular therapy that can simultaneously regenerate both tissues. The current protocol to derive bipotent mesodermal progenitors which can differentiate into cardiac and skeletal muscle relies on the spontaneous formation of embryoid bodies, thereby hampering further clinical translation. Additionally, as skeletal muscle is the largest organ in the human body, a high myogenic potential is necessary for successful regeneration. Here, we have optimized a protocol to generate chemically defined human induced pluripotent stem cell-derived mesodermal progenitors (cdMiPs). We demonstrate that these cells contribute to myotube formation and differentiate into cardiomyocytes, both in vitro and in vivo. Furthermore, the addition of valproic acid, a clinically approved small molecule, increases the potential of the cdMiPs to contribute to myotube formation that can be prevented by NOTCH signaling inhibitors. Moreover, valproic acid pre-treated cdMiPs injected in dystrophic muscles increase physical strength and ameliorate the functional performances of transplanted mice. Taken together, these results constitute a novel approach to generate mesodermal progenitors with enhanced myogenic potential using clinically approved reagents

Evaluation of Poly(Lactic-co-glycolic) Acid Alone or in Combination with Hydroxyapatite on Human-Periosteal Cells Bone Differentiation and in Sinus Lift Treatment

Most recent advances in tissue engineering in the fields of oral surgery and dentistry have aimed to restore hard and soft tissues. Further improvement of these therapies may involve more biological approaches and the use of dental tissue stem cells in combination with inorganic/organic scaffolds. In this study, we analyzed the osteoconductivity of two different inorganic scaffolds based on poly (lactic-co-glycolic) acid alone (PLGA-Fisiograft) or in combination with hydroxyapatite (PLGA/HA-Alos) in comparison with an organic material based on equine collagen (PARASORB Sombrero) both in vitro and in vivo. We developed a simple in vitro model in which periosteum-derived stem cells were grown in contact with chips of these scaffolds to mimic bone mineralization. The viability of cells and material osteoconductivity were evaluated by osteogenic gene expression and histological analyses at different time points. In addition, the capacity of scaffolds to improve bone healing in sinus lift was examined. Our results demonstrated that the osteoconductivity of PLGA/HA-Alos and the efficacy of scaffolds in promoting bone healing in the sinus lift were increased. Thus, new clinical approaches in sinus lift follow-up should be considered to elucidate the clinical potential of these two PLGA-based materials in dentistry

Evaluation of Poly(Lactic-co-glycolic) Acid Alone or in Combination with Hydroxyapatite on Human-Periosteal Cells Bone Differentiation and in Sinus Lift Treatment

Most recent advances in tissue engineering in the fields of oral surgery and dentistry have aimed to restore hard and soft tissues. Further improvement of these therapies may involve more biological approaches and the use of dental tissue stem cells in combination with inorganic/organic scaffolds. In this study, we analyzed the osteoconductivity of two different inorganic scaffolds based on poly (lactic-co-glycolic) acid alone (PLGA-Fisiograft) or in combination with hydroxyapatite (PLGA/HA-Alos) in comparison with an organic material based on equine collagen (PARASORB Sombrero) both in vitro and in vivo. We developed a simple in vitro model in which periosteum-derived stem cells were grown in contact with chips of these scaffolds to mimic bone mineralization. The viability of cells and material osteoconductivity were evaluated by osteogenic gene expression and histological analyses at different time points. In addition, the capacity of scaffolds to improve bone healing in sinus lift was examined. Our results demonstrated that the osteoconductivity of PLGA/HA-Alos and the efficacy of scaffolds in promoting bone healing in the sinus lift were increased. Thus, new clinical approaches in sinus lift follow-up should be considered to elucidate the clinical potential of these two PLGA-based materials in dentistry

Guide Cells Support Muscle Regeneration and Affect Neuro-Muscular Junction Organization

Muscular regeneration is a complex biological process that occurs during acute injury and chronic degeneration, implicating several cell types. One of the earliest events of muscle regeneration is the inflammatory response, followed by the activation and differentiation of muscle progenitor cells. However, the process of novel neuromuscular junction formation during muscle regeneration is still largely unexplored. Here, we identify by single-cell RNA sequencing and isolate a subset of vessel-associated cells able to improve myogenic differentiation. We termed them ‘guide’ cells because of their remarkable ability to improve myogenesis without fusing with the newly formed fibers. In vitro, these cells showed a marked mobility and ability to contact the forming myotubes. We found that these cells are characterized by CD44 and CD34 surface markers and the expression of Ng2 and Ncam2. In addition, in a murine model of acute muscle injury and regeneration, injection of guide cells correlated with increased numbers of newly formed neuromuscular junctions. Thus, we propose that guide cells modulate de novo generation of neuromuscular junctions in regenerating myofibers. Further studies are necessary to investigate the origin of those cells and the extent to which they are required for terminal specification of regenerating myofibers