Cells Tissues Organs最新文献

The extracellular matrix (ECM) is a complex, hierarchical material containing structural and bioactive components. This complexity makes decoupling the effects of biomechanical properties and cell-matrix interactions difficult, especially when studying cellular processes in a 3D environment. Matrix mechanics and cell adhesion are both known regulators of specific cellular processes such as stem cell proliferation and differentiation. However, more information is required about how such variables impact various neural lineages that could, upon transplantation, therapeutically improve neural function after a central nervous system injury or disease. Rapidly Assembling Pentapeptides for Injectable Delivery (RAPID) hydrogels are one biomaterial approach to meet these goals, consisting of a family of peptide sequences that assemble into physical hydrogels in physiological media. In this study, we studied our previously reported supramolecularly-assembling RAPID hydrogels functionalized with the ECM-derived cell-adhesive peptide ligands RGD, IKVAV, and YIGSR. Using molecular dynamics simulations and experimental rheology, we demonstrated that these integrin-binding ligands at physiological concentrations (3-12 mm) did not impact the assembly of the KYFIL peptide system. In simulations, molecular measures of assembly such as hydrogen bonding and pi-pi interactions appeared unaffected by cell-adhesion sequence or concentration. Visualizations of clustering and analysis of solvent-accessible surface area indicated that the integrin-binding domains remained exposed. KYFIL or AYFIL hydrogels containing 3 mm of integrin-binding domains resulted in mechanical properties consistent with their non-functionalized equivalents. This strategy of doping RAPID gels with cell-adhesion sequences allows for the precise tuning of peptide ligand concentration, independent of the rheological properties. The controllability of the RAPID hydrogel system provides an opportunity to investigate the effect of integrin-binding interactions on encapsulated neural cells to discern how hydrogel microenvironment impacts growth, maturation, or differentiation.

Decellularized scaffolds applied in tissue engineering offer improvements, supplying the elevated necessity for organs and tissues for replacement. However, obtaining a functional trachea for autotransplantation or allotransplantation is tricky due to the organ anatomical and structural complexity. Most tracheal decellularization protocols are lengthy, expensive, and could damage the tracheal extracellular matrix (ECM) architecture and functionality. Here, we aimed to evaluate the effectiveness of 3 different decellularization protocols combined with chemical and physical methods to obtain acellular canine tracheal scaffolds. Six adult dog tracheas were incised (tracheal segments) resulting in 28 rings for control tissue and 84 rings for decellularization (5-7 mm thick). Subsequently, decellularized tracheal scaffolds were microscopically/macroscopically characterized by histological analysis (Hematoxylin-Eosin, Masson's trichrome, Picrosirius red, Alcian blue, and Safranin O), immunohistochemistry for ECM components, scanning electron microscopy, and genomic DNA quantification. After decellularization, the tracheal tissue revealed reduced genomic DNA, and maintenance of ECM components preserved (structural proteins, adhesive glycoproteins, glycosaminoglycans and proteoglycans), suggesting ECM integrity and functionality. Comparatively, the combined ionic detergent with high vacuum pressure decellularization protocol revealed superior genomic DNA decrease (13.5 ng/mg) and improvement on glycosaminoglycans and proteoglycans preservation regarding the other decellularized trachea scaffolds and native tissue. Our results indicate that the 3 chemical/physical protocols reduce the decellularization time without ECM proteins damage. Notwithstanding, the use of ionic detergent under vacuum pressure was able to generate an innovative strategy to obtain acellular canine tracheal scaffolds with the highest levels of adhesive proteins that support its potentiality for recellularization and future tissue engineering application.

The presence of mesenchymal progenitor cells (MPCs) in rheumatoid arthritis (RA) articular cartilage is sparsely investigated largely owing to the persistent pathogenic disease condition and lack of specific biomarkers. Considering the recent advancements for potential cell-based therapies in immunomodulatory diseases, such as RA, this in vitro study was aimed at investigating the cellular, molecular, and differentiation characteristics of human RA cartilage-derived MPCs. Articular cartilage fragments from RA patients were obtained for the isolation of MPCs and characterization of their cellular and biological properties, cytogenetic stability, pluripotency, and plasticity. Established MPCs were phenotypically identified using a panel of markers, and their differentiation ability into mesenchymal lineages was assessed by cytochemical staining and the expression of molecular markers. MPCs displayed a heterogenous population of cells with characteristic features of multipotent stem cells. Cells had higher viability, proliferative rate, and colony-forming ability. Further, MPCs showed the expression of pluripotency markers, cytogenetic stability, and minimal replicative senescence. In addition, MPCs differentiated into osteocytes, adipocytes, and chondrocytes, and modulated the expression of each lineage-specific gene markers. The results demonstrated the availability of a viable pool of MPCs residing in RA cartilage, which could serve as an ideal cell source for reinstating native homotypic cartilage.

Coronary artery disease (CAD) is the first leading cause of death worldwide. Therefore, novel therapeutic strategies need to be explored. Numerous publications reported that microRNA-654-5p (miR-654-5p) had anti-cancer activities in various cancers, and it was proven to modulate cell migration, invasion, and proliferation, which played critical roles in CAD. However, its role in CAD is unknown. Thus, we aimed to evaluate the role of miR-654-5p in vascular smooth muscle cells (VSMCs) involved in CAD. A total of 25 CAD patients and 19 healthy individuals were enrolled to evaluate their circulating miR-654-5p levels. miR-654-5p mimic or inhibitor were transfected into human VSMCs to assess their role on cell migration and proliferation. Target genes of miR-654-5p were predicted using TargetScan 7.2 and confirmed by the dual-luciferase reporter assay. miR-654-5p was significantly downregulated in the plasma of CAD patients and tumor necrosis factor-a/platelet-derived growth factor (PDGF)-BB-stimulated VSMCs. miR-654-5p mimic inhibited the proliferation and migration of VSMCs, which could be promoted by miR-654-5p inhibitor. A disintegrin and metalloproteinase with thrombospondin motifs-7 (ADAMTS-7) was identified as the direct target of miR-654-5p, whose expression could be induced by miR-654-5p inhibitor and decreased by its mimic. In addition, ADAMTS-7 overexpression blocked the inhibitory effect of miR-654-5p on the migration and proliferation of VSMCs. In summary, miR-654-5p inhibits the migration and proliferation of VSMCs by directly targeting ADAMTS-7, and miR-654-5p might serve as a novel therapeutic target for the treatment of CAD.

Traditionally, tissue-specific organoids are generated as 3D aggregates of stem cells embedded in Matrigel or hydrogels, and the aggregates eventually end up a spherical shape and suspended in the matrix. Lack of geometrical control of organoid formation makes these spherical organoids limited for modeling the tissues with complex shapes. To address this challenge, we developed a new method to generate 3D spatial-organized cardiac organoids from 2D micropatterned human induced pluripotent stem cell (hiPSC) colonies, instead of directly from 3D stem cell aggregates. This new approach opens the possibility to create cardiac organoids that are templated by 2D non-spherical geometries, which potentially provides us a deeper understanding of biophysical controls on developmental organogenesis. Here, we designed 2D geometrical templates with quadrilateral shapes and pentagram shapes that had same total area but different geometrical shapes. Using this templated substrate, we grew cardiac organoids from hiPSCs and collected a series of parameters to characterize morphological and functional properties of the cardiac organoids. In quadrilateral templates, we found that increasing the aspect ratio impaired cardiac tissue 3D self-assembly, but the elongated geometry improved the cardiac contractile functions. However, in pentagram templates, cardiac organoid structure and function were optimized with a specific geometry of an ideal star shape. This study will shed a light on "organogenesis-by-design" by increasing the intricacy of starting templates from external geometrical cues to improve the organoid morphogenesis and functionality.

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease. This study explored the mechanism of miR-181a-5p in the inflammatory response in COPD mice. COPD mouse models were established by cigarette smoke (CS) exposure following pretreatment with recombinant adeno-associated virus (rAAv)-miR-181a-5p, si-HMGB1 (high mobility group box 1), and NF-κB pathway inhibitor PDTC, respectively. Pathological changes of lung tissues were determined by HE staining. Bronchoalveolar lavage fluid was collected to count total cells, neutrophils, and lymphocytes using a Countess II automatic cell counter. Expressions of neutrophil elastase (NE) and inflammatory factors (TNF-α, IL-6, IL-8, and IFN-γ) were detected by ELISA. Binding relationship between miR-181a-5p and HMGB1 was predicted on starBase and validated by dual-luciferase assay. miR-181a-5p expression was detected by RT-qPCR, and expressions of HMGB1, IκBα, and p-IκBα were detected by western blot. The expression level of miR-181a-5p was lower in lung tissues. miR-181a-5p overexpression alleviated inflammatory response and pathological changes of lung tissues in COPD mice, with decreased pulmonary inflammation scores, total cells, neutrophils, and lymphocytes and expressions of NE and inflammatory factors. HMGB1 expression level was increased in COPD mice. miR-181a-5p targeted HMGB1. si-HMGB1 relieved inflammatory responses in COPD mice. NF-κB was activated in COPD mice, evidenced by degraded IκBα and increased p-IκBα levels. si-HMGB1 significantly restrained the activation of NF-κB pathway. Briefly, miR-181a-5p targets HMGB1 to inhibit the NF-κB pathway, thus alleviating the inflammatory response in COPD mice.

Sepsis is a systemic infection mainly caused by bacterial infections. Despite all efforts and advances in the treatment of sepsis, it is still considered one of the leading causes of death in hospitalized patients. Today, we have to use novel therapies and one of the most important is cell-free therapy. Exosomes have been shown to contain the contents of their parent cells and that they do not generate an immune response between different individuals which makes them a good candidate for transplantation. Unrestricted somatic stem cells (USSC), also known as mesenchymal stem cell progenitors due to their high proliferative capacity and low immune response, may be a novel therapy for sepsis. In this study, the effect of USSC-derived exosomes on sepsis was investigated using a mouse model. USSCs were isolated from human cord blood and characterized by flow cytometry and multi-lineage differentiation. The exosomes were then harvested from USSCs and characterized by transmission electron microscopy, Western blotting, and dynamic light scattering. The harvested exosomes were injected into the mouse model of sepsis. Biochemical, histological, molecular, and survival studies were performed in different groups. Our observations showed that USSC-derived exosomes can reduce inflammation in septic mice. Histopathologic and biochemical findings in the sham group showed multiorgan involvement, but these changes disappeared after 7 days of exosome administration. Moreover, the expression of IRAK-1 and TRAF-6 (main adapter molecules in signaling pathways of inflammation) was decreased through negative regulation by miR-146a after 72 h of exosome administration. A 2-fold increase in the level of IL-10 and a 2-fold decrease in the levels of IL-6 and TNF-α was observed. In conclusion, we showed that direct injection of USSC-derived exosomes can be one of the important methods for the treatment of various aspects of sepsis due to their immunomodulatory properties.

The rat model is an important resource in biomedical research due to its similarities to the human immune system and its use for functional studies. However, because of the preponderance of mouse models in foundational and mechanistic immunological studies, there is a relative lack of diverse, commercially available flow cytometry antibodies for immunological profiling in the rat model. Available antibodies are often conjugated to common fluorophores with similar peak emission wavelengths, making them hard to distinguish on conventional flow cytometers and restricting more comprehensive immune analysis. This can become a limitation when designing immunological studies in rat injury models to investigate the immune response to tissue injury. In addition, this lack of available antibodies limits the number of studies that can be done on the immune populations in lymphoid organs in other research areas. To address this critical unmet need, we designed a spectral flow cytometry panel for rat models. Spectral cytometry distinguishes between different fluorophores by capturing their full emission spectra instead of their peak emission wavelengths. This flow cytometry panel includes 24 distinct immune cell markers to analyze the innate and adaptive immune response. Importantly, this panel identifies different immune phenotypes, including tolerogenic, Type 1, and Type 2 immune responses. We show that this panel can identify unique immune populations and phenotypes in a rat muscle trauma model. We further validated that the panel can identify distinct adaptive and innate immune populations and their unique phenotypes in lymphoid organs. This panel expands the scope of previous rat panels providing a tool for scientists to examine the immune system in homeostasis and injury while pairing mechanistic immunological studies with functional studies.