White adipose tissue (WAT) is an essential regulator of energy storage and systemic metabolic homeostasis. Regulatory networks consisting of immune and structural cells are necessary to maintain WAT ...metabolism, which can become impaired during obesity in mammals. Using single-cell transcriptomics and flow cytometry, we unveil a large-scale comprehensive cellular census of the stromal vascular fraction of healthy lean and obese human WAT. We report new subsets and developmental trajectories of adipose-resident innate lymphoid cells, dendritic cells and monocyte-derived macrophage populations that accumulate in obese WAT. Analysis of cell-cell ligand-receptor interactions and obesity-enriched signaling pathways revealed a switch from immunoregulatory mechanisms in lean WAT to inflammatory networks in obese WAT. These results provide a detailed and unbiased cellular landscape of homeostatic and inflammatory circuits in healthy human WAT.
Fibroblasts are found in most tissues of the body. They exhibit several phenotypes including non-contractile fibroblasts, contractile myofibroblasts, and intermediate phenotypes including the ...protomyofibroblast. Fibroblasts are metabolically active cells which play critical roles regulating extracellular matrices, interstitial fluid volume and pressure, and wound healing. Fibroblast numbers can be maintained or expanded by proliferation of resident populations but in addition, recent evidence indicates they can also be derived through epithelial-mesenchymal transition or from circulating and tissue-derived mesenchymal stem cells. Many diseases are associated with dysregulation of the injury repair response and fibroblast function, leading to increased or decreased deposition of extracellular matrix proteins, altered tissue architecture, impaired function and in some cases significant morbidity and mortality. There are currently no specific therapies that target fibroblast-associated pathology but increasing knowledge of pathological mechanisms has led to development of new agents providing hope for improved treatment of these diseases.
Calcific aortic valve stenosis is a common disease in the elderly and is characterized by progressive calcification and fibrous thickening of the valve, but the cellular and molecular mechanisms are ...not fully understood. We hypothesized that human valve interstitial cells (ICs) are able to differentiate into osteoblast-like cells through the influence of defined mediators and that this process can be modulated pharmacologically.
To test this hypothesis, we treated primary cultures of human aortic valve ICs with osteogenic media, bone morphogenic proteins (BMPs BMP-2, BMP-4, and BMP-7), and tissue growth factor-beta (TGF-beta TGF-beta1 and TGF-beta3) for 21 days. These mediators induced osteoblast differentiation of valve ICs by significantly increasing the activity and expression of alkaline phosphatase (ALP P<0.001). A cytokine protein array revealed that atorvastatin treatment (100 micromol/L) of human valve ICs caused a downregulation in levels of expression of BMP-2, BMP-6, TGF-beta1, and TGF-beta3 after 24 hours. In addition, human valve ICs treated with atorvastatin in the presence of osteogenic media showed a significant reduction in ALP activity in comparison to cells treated with osteogenic media only (P=<0.001). This was further confirmed with immunocytochemical staining of valve ICs, whereby atorvastatin markedly reduced the expression of ALP and osteocalcin induced by osteogenic media in comparison to untreated cells.
These findings suggest that human valve ICs are capable of osteoblastic differentiation, by potential mediators which can be pharmacologically targeted by atorvastatin.
Amputation of the axolotl forelimb results in the formation of a blastema, a transient tissue where progenitor cells accumulate prior to limb regeneration. However, the molecular understanding of ...blastema formation had previously been hampered by the inability to identify and isolate blastema precursor cells in the adult tissue. We have used a combination of Cre-loxP reporter lineage tracking and single-cell messenger RNA sequencing (scRNA-seq) to molecularly track mature connective tissue (CT) cell heterogeneity and its transition to a limb blastema state. We have uncovered a multiphasic molecular program where CT cell types found in the uninjured adult limb revert to a relatively homogenous progenitor state that recapitulates an embryonic limb bud-like phenotype including multipotency within the CT lineage. Together, our data illuminate molecular and cellular reprogramming during complex organ regeneration in a vertebrate.
Mast cells are evolutionarily ancient sentinel cells. Like basophils, mast cells express the high-affinity receptor for immunoglobulin E (IgE) and have been linked to host defense and diverse ...immune-system-mediated diseases. To better characterize the function of these cells, we assessed the transcriptional profiles of mast cells isolated from peripheral connective tissues and basophils isolated from spleen and blood. We found that mast cells were transcriptionally distinct, clustering independently from all other profiled cells, and that mast cells demonstrated considerably greater heterogeneity across tissues than previously appreciated. We observed minimal homology between mast cells and basophils, which shared more overlap with other circulating granulocytes than with mast cells. The derivation of mast-cell and basophil transcriptional signatures underscores their differential capacities to detect environmental signals and influence the inflammatory milieu.
Hyaluronic acid (HA) is an extracellular matrix (ECM) component that has been shown to play a significant role in regulating muscle cell behavior during repair and regeneration. For instance, ECM ...remodeling after muscle injury involves an upregulation in HA expression that is coupled with skeletal muscle precursor cell recruitment. However, little is known about the role of HA during skeletal muscle development. To gain insight into the way in which HA mediates embryonic myogenesis, we first determined the spatial distribution and gene expression of CD44, RHAMM and other HA related proteins in embryonic day (E)10.5 to E12.5 murine forelimbs. While HA and CD44 expression remained high, RHAMM decreased at both the protein (via immunohistochemistry) and RNA (via qPCR) levels. Next, we determined that 4-methylumbelliferone-mediated knockdown of HA synthesis inhibited the migration and proliferation of E11.5/E12.5 forelimb-derived cells. Then, the influence of CD44 and RHAMM on myoblast and connective tissue cell behavior was investigated using antibodies against these receptors. Anti-RHAMM, but not anti-CD44, significantly decreased the total distance myogenic progenitors migrated over 24 h, whereas both inhibited connective tissue cell migration. In contrast, anti-CD44 inhibited the proliferation of connective tissue cells and muscle progenitors, but anti-RHAMM had no effect. However, when myoblasts and connective tissue cells were depleted of CD44 and RHAMM by shRNA, motility and proliferation were significantly inhibited in both cells indicating that blocking cell surface-localized CD44 and RHAMM does not have as pronounced effect as global shRNA-mediated depletion of these receptors. These results show, for the first time, the distribution and activity of RHAMM in the context of skeletal muscle. Furthermore, our data indicate that HA, through interactions with CD44 and RHAMM, promotes myogenic progenitor migration and proliferation. Confirmation of the role of HA and its receptors in directing myogenesis will be useful for the design of regenerative therapies that aim to promote the restoration of damaged or diseased muscle.
•CD44, RHAMM and HA expression temporally varied during forelimb development.•shRNA-mediated depletion of CD44 and RHAMM inhibited proliferation and migration.•Antibody blocking of CD44 and RHAMM had a differential effect than shRNA depletion.
Background A biomarker that predicts poor asthma control would be clinically useful. Fibrocytes are bone marrow–derived circulating progenitor cells that have been implicated in tissue fibrosis and ...TH 2 responses in asthmatic patients. Objective We sought to test the hypothesis that the concentration and activation state of peripheral blood fibrocytes correlates with asthma severity. Methods By using fluorescence-activated cell sorting analysis, fibrocytes (CD45+ and collagen 1 Col1+ ) were enumerated and characterized in the buffy coats of fresh peripheral blood samples from 15 control subjects and 40 asthmatic patients. Results Concentrations of peripheral blood total (CD45+ Col1+ ), activated (the TGF-β transducing protein phosphorylated SMAD2/3 p-SMAD2/3+ or phosphorylated AKT p-AKT+ ), and differentiated (α-smooth muscle actin α-SMA+ ) fibrocytes were increased in asthmatic patients compared with control subjects. The increase in total and CD45+ Col1+ CXCR4+ fibrocytes was primarily seen in patients with severe asthma (Global Initiative for Asthma steps 4-5) as opposed to those with milder asthma (Global Initiative for Asthma steps 1-3). In addition, numbers of circulating α-SMA+ and α-SMA+ CXCR4+ fibrocytes were increased in asthmatic patients experiencing an asthma exacerbation in the preceding 12 months. A significant correlation ( P < .05) was observed between CD45+ Col1+ CXCR4+ fibrocytes and the activation phenotypes CD45+ Col1+ p-SMAD2/3+ and CD45+ Col1+ p-AKT+. Conclusion There was correlation between circulating fibrocyte subsets and asthma severity, and there was an increased number of activated/differentiated fibrocytes in circulating blood of asthmatic patients experiencing an exacerbation in the preceding 12 months.
Abstract In the field of soft tissue reconstruction, custom implants could address the need for materials that can fill complex geometries. Our aim was to develop a material system with optimal ...rheology for material extrusion, that can be processed in physiological and non-toxic conditions and provide structural support for soft tissue reconstruction. To meet this need we developed silk based bioinks using gelatin as a bulking agent and glycerol as a non-toxic additive to induce physical crosslinking. We developed these inks optimizing printing efficacy and resolution for patient-specific geometries that can be used for soft tissue reconstruction. We demonstrated in vitro that the material was stable under physiological conditions and could be tuned to match soft tissue mechanical properties. We demonstrated in vivo that the material was biocompatible and could be tuned to maintain shape and volume up to three months while promoting cellular infiltration and tissue integration.
Tendons are traditionally thought to consist of tenocytes only, the resident cells of tendons; however, a recent study has demonstrated that human and mouse tendons also contain stem cells, referred ...to as tendon stem/progenitor cells (TSCs). However, the differential properties of TSCs and tenocytes remain largely undefined. This study aims to characterize the properties of these tendon cells derived from rabbits.
TSCs and tenocytes were isolated from patellar and Achilles tendons of rabbits. The differentiation potential and cell marker expression of the two types of cells were examined using histochemical, immunohistochemical, and qRT-PCR analysis as well as in vivo implantation. In addition, morphology, colony formation, and proliferation of TSCs and tenocytes were also compared.
It was found that TSCs were able to differentiate into adipocytes, chondrocytes, and osteocytes in vitro, and form tendon-like, cartilage-like, and bone-like tissues in vivo. In contrast, tenocytes had little such differentiation potential. Moreover, TSCs expressed the stem cell markers Oct-4, SSEA-4, and nucleostemin, whereas tenocytes expressed none of these markers. Morphologically, TSCs possessed smaller cell bodies and larger nuclei than ordinary tenocytes and had cobblestone-like morphology in confluent culture whereas tenocytes were highly elongated. TSCs also proliferated more quickly than tenocytes in culture. Additionally, TSCs from patellar tendons formed more numerous and larger colonies and proliferated more rapidly than TSCs from Achilles tendons.
TSCs exhibit distinct properties compared to tenocytes, including differences in cell marker expression, proliferative and differentiation potential, and cell morphology in culture. Future research should investigate the mechanobiology of TSCs and explore the possibility of using TSCs to more effectively repair or regenerate injured tendons.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cancer cells have been at the centre of cell metabolism research, but the metabolism of stromal and immune cells has received less attention. Nonetheless, these cells influence the progression of ...malignant, inflammatory and metabolic disorders. Here we discuss the metabolic adaptations of stromal and immune cells in health and disease, and highlight how metabolism determines their differentiation and function.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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