Supplementation with autologous adipose stem cell-derived mitochondria can be a safe and promising strategy for improving oocyte quality

PURPOSE

In our previous study, we confirmed that the supplementation of vitrified-warmed murine oocytes with autologous adipose stem cell (ASC)-derived mitochondria during intracytoplasmic sperm injection enhances post-fertilization developmental competence in mice. To ensure the safety of this technology, we conducted a thorough study in mice to investigate the potential presence of specific malformations in offspring developed from this approach.

METHODS

A transgenerational comparative analysis was conducted on founder mice from embryos that developed after mitochondrial supplementation, and two subsequent generations. Reproductive performance, body growth rate, histopathological parameters, hematological parameters, daily activity patterns, and daily body temperature changes in male and female mice across these three generations were assessed in comparison to wild-type mice of the same age.

RESULTS

Both male and female animals in all three generations showed comparable reproductive performance to the control group. Additionally, body growth rate by the age of 8 weeks were found to be comparable to controls across all three generations. Notably, no significant histopathological abnormalities were detected in vital organs, including the brain, heart, liver, kidneys, lungs, ovaries, and testes, in any individuals from the studied cohorts. The blood parameters were consistent with the control data. The continuous monitoring of activity and body temperature changes (both day and night) over a 1-week period revealed a pattern closely resembling that observed in the control animals.

CONCLUSION

Injection of ASC-mitochondria into oocytes may be a promising technique to support developmental potential without causing adverse epigenetic events in the offspring in mice. However, before considering clinical application, additional safety screening using larger animals or non-human primates is essential.

ADSC-Exos enhance functional recovery after spinal cord injury by inhibiting ferroptosis and promoting the survival and function of endothelial cells through the NRF2/SLC7A11/GPX4 pathway

BACKGROUND

Spinal cord injury (SCI) is a devastating disease that causes major motor, sensory and autonomic dysfunctions. Currently, there is a lack of effective treatment. In this study, we aimed to investigate the potential mechanisms of Exosomes from adipose-derived stem cells (ADSC-Exos) in reducing ferroptosis and promoting angiogenesis after spinal cord injury.

METHODS

We isolated ADSC-Exos, the characteristics of which were confirmed. In vitro, we tested the potential of ADSC-Exos to promote the survival and function of human brain microvascular endothelial cells (HBMECs) and analyzed the ferroptosis of HBMECs. In vivo, we established rat models of SCI and locally injected ADSC-Exos to verify their efficacy.

RESULTS

ADSC-Exos can reduce reactive oxygen species (ROS) accumulation and cell damage induced by an excessive inflammatory response in HBMECs. ADSC-Exos inhibit ferroptosis induced by excessive inflammation and upregulate the expression of glutathione peroxidase 4(GPX4) in HBMECs. It can also effectively promote proliferation, migration, and vessel-like structure formation. In vitro, ADSC-Exos improved behavioral function after SCI and increased the number and density of blood vessels around the damaged spinal cord. Moreover, we found that ADSC-Exos could increase nuclear factor erythroid-2-related factor 2(NRF2) expression and nuclear translocation, thereby affecting the expression of solute carrier family 7 member 11(SLC7A11) and GPX4, and the NRF2 inhibitor ML385 could reverse the above changes.

CONCLUSION

Our results suggest that ADSC-Exos may inhibit ferroptosis and promote the recovery of vascular and neural functions after SCI through the NRF2/SLC7A11/GPX4 pathway. This may be a potential therapeutic mechanism for spinal cord injury.

The Effect of Fat Grafting on Scars Hyperpigmentation: A Systematic Review and Meta-Analysis

BACKGROUND

Hyperpigmented scars, particularly in exposed body areas, can be difficult to conceal and may evoke psychological distress. While the precise causes of scar dyschromia are not fully understood, alterations in melanogenic activity appear to hold more significance than changes in melanocyte quantity. Current treatments encompass laser interventions. However, it is essential to consider their costs and potential complications in relation to their limited proven effectiveness. Fat grafting has gained interest as a scar modulation technique due to its regenerative properties, and its efficacy in reducing scar hyperpigmentation is currently under investigation.

METHODS

A systematic review and meta-analysis was reported according to PRISMA guidelines. PubMed, Embase, and Cochrane Library databases were accessed. PROSPERO registration number is CRD42023457778. The primary outcome was a change in scar pigmentation after fat grafting. Pigmentation changes after fat grafting were calculated using the standardized mean difference (SMD) between baseline and postoperative scores according to POSAS and VSS scales. Bias assessment was conducted according to the National Institute for Health and Clinical Excellence quality assessment tool.

RESULTS

A total of 8 articles meeting inclusion and exclusion criteria were identified, involving 323 patients with hyperpigmented scars treated with fat grafting. A significant difference in scar pigmentation was noted after treatment with fat grafting according to observers' ratings, with a SMD of - 1.09 [95% CI: - 1.32; - 0.85], p<0.01. The SMD for patient-reported scar pigmentation after treatment with fat grafting was - 0.99 [96% CI: - 1.31; - 0.66], p<0.01. Four studies provided objective measurements of melanin changes after fat grafting and revealed inconsistent findings compared to subjective observations.

CONCLUSIONS

Fat grafting shows promise in ameliorating hyperpigmented scars based on subjective assessments, but further corroborating evidence from objective measures is required.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Unlocking the versatile potential: Adipose-derived mesenchymal stem cells in ocular surface reconstruction and oculoplastics

This review comprehensively explores the versatile potential of mesenchymal stem cells (MSCs) with a specific focus on adipose-derived MSCs. Ophthalmic and oculoplastic surgery, encompassing diverse procedures for ocular and periocular enhancement, demands advanced solutions for tissue restoration, functional and aesthetic refinement, and aging. Investigating immunomodulatory, regenerative, and healing capacities of MSCs, this review underscores the potential use of adipose-derived MSCs as a cost-effective alternative from bench to bedside, addressing common unmet needs in the field of reconstructive and regenerative surgery.

coli infected wound model in Rats

Skin infections by pathogenic microorganisms are a serious problem due to the potential of dissemination through the bloodstream to various organs causing toxic effects that may be up to mortality. Escherichia coli (E. coli) is one of the most predominant Gram-negative bacterial species present globally with great attention for investigation. The current study is designed to investigate the possible role of adipose tissue-derived stem cells (ADSCs), as well as natural products such as Trichoderma viride (T. viride) extract, Saccharomyces boulardii (S. boulardii) solution in the enhancement of wound healing process in the infected skin with E. coli. Ninety-six female rats were divided into 8 groups (12 animal/group): normal skin, wounded skin, wounded skin infected with E. coli, infected-wounded skin treated by ADSCs, infected-wounded skin treated by T. viride extract, infected-wounded skin treated by S. boulardii solution, infected-wounded skin treated a combination of treatments, infected-wounded skin treated by gentamicin. At day 21 animal weights and bacterial count were detected and compared. Animals were sacrificed and skin from various groups was investigated using a light microscope for sections stained by (hematoxylin eosin, Masson trichrome, and PCNA) as well as transmission electron microscopy. Pro-inflammatory (IL-1β, TNF- α, and IL-13), anti-inflammatory cytokine (IL-4), and antioxidant enzymes (Superoxide dismutase, glutathione, and catalase) were assessed in various groups revealing that ADSCs lightly shift levels of these parameters in various rat groups to regular levels, while administration of T. viride extract, S. boulardii solution, their combination with ADSCs and gentamicin treatment drive the tested cytokines and enzymes to significant levels similar to a normal level where combination therapy gave the best result. The current findings revealed the possibility of using certain natural products as possible substitutes to regularly applied antibiotics with successive protective results in the wound infection model.

Deciphering the role of extrachromosomal circular DNA in adipose stem cells from old and young donors

BACKGROUND

The functional impairment of adipose stem cells (ASCs) during aging limits their clinical transformation. Studies have shown that extrachromosomal circular DNAs (eccDNAs) are associated with tumor progression and cell aging, but the roles of eccDNAs in ASCs remain unknown.

METHOD

We conducted Circle sequencing (Circle-seq) to identify eccDNAs in ASCs isolated from young and old donors. The differentially expressed eccDNAs were calculated, annotated and validated via polymerase chain reaction.

RESULTS

Thousands of eccDNAs were identified and comprehensively characterized. Most of them were GC-rich, < 1000 base pairs in size, and were enriched on chromosome 19 and 17 with a high density of Alu elements and genes, 2 kb upstream/downstream of genes and satellites. In total, 3025 eccDNAs were differentially expressed among the two ASC groups. Conjoint analysis of the Circle-seq results and previous RNA-seq results revealed that 73 eccDNAs and 55 genes exhibited the same differential expression between the two groups. KEGG and GO analyses revealed that genes encoding differentially expressed eccDNAs were enriched for cell adhesion, cellular senescence and TGF-β receptor signaling pathway. We also found that aged ASCs exhibited loss of eccDNAs, including CAMK2G (chr10: 75577899-75578176), TRABD2B (chr1: 48305638-48307008) and TRABD2B (chr1: 48305425-48307091).

CONCLUSION

In this study, we elucidated the first eccDNA profile relating to ASCs and demonstrated that three eccDNAs are lost in aged ASCs, which may be potential biomarkers of stem cell aging and valuable targets for stem cell rejuvenation.

Local euchromatin enrichment in lamina-associated domains anticipates their repositioning in the adipogenic lineage

Background

Interactions of chromatin with the nuclear lamina via lamina-associated domains (LADs) confer structural stability to the genome. The dynamics of positioning of LADs during differentiation, and how LADs impinge on developmental gene expression, remains, however, elusive.

Results

We examined changes in the association of lamin B1 with the genome in the first 72 h of differentiation of adipose stem cells into adipocytes. We demonstrate a repositioning of entire stand-alone LADs and of LAD edges as a prominent nuclear structural feature of early adipogenesis. Whereas adipogenic genes are released from LADs, LADs sequester downregulated or repressed genes irrelevant for the adipose lineage. However, LAD repositioning only partly concurs with gene expression changes. Differentially expressed genes in LADs, including LADs conserved throughout differentiation, reside in local euchromatic and lamin-depleted sub-domains. In these sub-domains, pre-differentiation histone modification profiles correlate with the LAD versus inter-LAD outcome of these genes during adipogenic commitment. Lastly, we link differentially expressed genes in LADs to short-range enhancers which overall co-partition with these genes in LADs versus inter-LADs during differentiation.

Conclusions

We conclude that LADs are predictable structural features of adipose nuclear architecture that restrain non-adipogenic genes in a repressive environment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13059-022-02662-6.

Loss of thymidine phosphorylase activity disrupts adipocyte differentiation and induces insulin-resistant lipoatrophic diabetes

BACKGROUND

Thymidine phosphorylase (TP), encoded by the TYMP gene, is a cytosolic enzyme essential for the nucleotide salvage pathway. TP catalyzes the phosphorylation of the deoxyribonucleosides, thymidine and 2'-deoxyuridine, to thymine and uracil. Biallelic TYMP variants are responsible for Mitochondrial NeuroGastroIntestinal Encephalomyopathy (MNGIE), an autosomal recessive disorder characterized in most patients by gastrointestinal and neurological symptoms, ultimately leading to death. Studies on the impact of TYMP variants in cellular systems with relevance to the organs affected in MNGIE are still scarce and the role of TP in adipose tissue remains unexplored.

METHODS

Deep phenotyping was performed in three patients from two families carrying homozygous TYMP variants and presenting with lipoatrophic diabetes. The impact of the loss of TP expression was evaluated using a CRISPR-Cas9-mediated TP knockout (KO) strategy in human adipose stem cells (ASC), which can be differentiated into adipocytes in vitro. Protein expression profiles and cellular characteristics were investigated in this KO model.

RESULTS

All patients had TYMP loss-of-function variants and first presented with generalized loss of adipose tissue and insulin-resistant diabetes. CRISPR-Cas9-mediated TP KO in ASC abolished adipocyte differentiation and decreased insulin response, consistent with the patients' phenotype. This KO also induced major oxidative stress, altered mitochondrial functions, and promoted cellular senescence. This translational study identifies a new role of TP by demonstrating its key regulatory functions in adipose tissue.

CONCLUSIONS

The implication of TP variants in atypical forms of monogenic diabetes shows that genetic diagnosis of lipodystrophic syndromes should include TYMP analysis. The fact that TP is crucial for adipocyte differentiation and function through the control of mitochondrial homeostasis highlights the importance of mitochondria in adipose tissue biology.

Generating adipose stem cell-laden hyaluronic acid-based scaffolds using 3D bioprinting via the double crosslinked strategy for chondrogenesis

Bioprinting of most cell-laden hydrogel scaffolds with the required structural integrity, mechanical modulus, cell adhesion, cell compatibility, and chondrogenic differentiation are still significant issues that affect the application of bioinks in cartilage tissue engineering. This study focuses on constructing printable bioinks by combining adipose-derived stem cells (ADSCs), hyaluronic acid (HA)-based hydrogels and analyzing their ability to induce chondrogenesis using 3D bioprinting technology. First, biotinylated hyaluronic acid was synthesized via an adipic acid dihydrazide (ADH) linker with amide bond formation to form HA-biotin (HAB). Both HAB and the as-received streptavidin were mixed to form a partially cross-linked HA-biotin-streptavidin (HBS) hydrogel through noncovalent bonding. After that, the partially cross-linked HBS hydrogel was mixed with sodium alginate and subsequently printed to form the HBSA hydrogel 3D scaffolds using a bioprinter. Finally, the 3D scaffolds of the HBSA (HBS + alginate) hydrogel were submerged into CaCl₂ solution to achieve a stable 3D HBSAC (HBSA + Ca²⁺) hydrogel scaffold through ion transfer crosslinking. The physical-chemical characteristics of the hybrid bioink compositions have been evaluated to determine the desired 3D bioprinting structure. Cytotoxicity and chondrogenic differentiation were also assessed to confirm that the double cross-linked HBSAC hydrogel scaffold was useful for chondrogenic formation. The results showed that partially crosslinking the biotinylated HA-based hydrogel with streptavidin has a significant effect on printability and structural integrity. Morphological analysis of a suitable 3D printed HBSAC hydrogel scaffold showed visible pores with the desired shape and geometry. We have concluded that the HBSAC hydrogel possesses a favorable biocompatibility profile. The HBSAC hydrogel can also secrete significantly higher amounts of chondrogenic marker genes at day 5 and sulfated glycosaminoglycans (sGAGs) from days 7 to 14 compared to the HA hydrogel, as determined via quantitative real-time PCR assay and Alcian blue staining and the DMMB assay.

Sprouty1 Prevents Cellular Senescence Maintaining Proliferation and Differentiation Capacity of Human Adipose Stem/Progenitor Cells

The role of Ras-Mitogen-activated protein kinase (MAPK) signaling in cellular aging is not precisely understood. Recently, we identified Sprouty1 (SPRY1) as a weight-loss target gene in human adipose stem/progenitor cells (ASCs) and showed that Sprouty1 is important for proper regulation of adipogenesis. In the present study, we show that loss-of-function of Sprouty1 by CRISPR/Cas9-mediated genome editing in human ASCs leads to hyper-activation of MAPK signaling and a senescence phenotype. Sprouty1 knockout ASCs undergo an irreversible cell cycle arrest, become enlarged and stain positive for senescence-associated β-galactosidase. Sprouty1 down-regulation leads to DNA double strand breaks, a considerably increased number of senescence-associated heterochromatin foci and induction of p53 and p21^Cip1. In addition, we detect an increase of hypo-phosphorylated Retinoblastoma (Rb) protein in SPRY1 knockout ASCs. p16^Ink4A is not induced. Moreover, we show that Sprouty1 knockout leads to induction of a senescence-associated secretory phenotype as indicated by the activation of the transcription factors NFκB and C/EBPβ and a significant increase in mRNA expression and secretion of interleukin-8 (IL-8) and CXCL1/GROα. Finally, we demonstrate that adipogenesis is abrogated in senescent SPRY1 knockout ASCs. In conclusion, this study reveals a novel mechanism showing the importance of Sprouty1 for the prevention of senescence and the maintenance of the proliferation and differentiation capacity of human ASCs.

Cardiac stem cell therapy among Clinics of Uncertain Regulatory Status (COURS): under-regulated, under-observed, incompletely understood

Background

Although a large body of information exists relating to cellular therapies, much of this information is either anecdotal or has been obtained from relatively small clinical trials, so that the level of evidence available to direct adoption of therapeutic approaches is quite limited. Despite this, a large number of clinics offer various cellular treatments without having gone through the processes of FDA approval. Florida is considered a “hotspot” of such sites, with a large number of clinics relative to the population.

Methods

To better understand the magnitude and scope of this issue with a specific focus on cardiovascular disease, we surveyed clinics in Florida advertising “cell therapy for heart failure”. We identified only 8 clinics that “treat cardiac conditions, including heart failure.” Data on administration route, cell type used, dose, success rate, cost, and training of persons performing procedures were collected when available, via email, telephone, or website information.

Results

A total of 20,135 patients were identified as treated: 2157 for cardiac conditions. All clinics reported administering cells intravenously, using either adipose- or umbilical-derived sources. Doses ranged from 30 to 150 million cells per treatment. The “success rate” ranged from 65 to 85%, with costs from $6000 to $20,700. Procedures were performed by PAs, MDs, and DOs.

Conclusion

Large numbers of patients (> 10% of all 20,135 patients) have been and presumably are still are being treated for “cardiac conditions.” We conclude that implementation of uniform data collection with an outcome registry, as well as creation of a public database listing FDA-approved cell-based clinical trials, would be useful to patients and the cardiovascular field at large.

Suppressor Effects of Sodium Pentaborate Pentahydrate and Pluronic F68 on Adipogenic Differentiation and Fat Accumulation

Obesity is a major public health problem worldwide and a risk factor for certain diseases, including cardiovascular disease, diabetes, cancer, and depression. Unfortunately, currently available anti-obesity drugs have failed in the long-term maintenance of weight control. It has been a challenge to design novel drugs that could potentially treat obesity or prevent uncontrolled weight-gain which lies underneath the pathology of obesity. Since obesity in a way is a consequence of the accumulating new mature adipocytes from undifferentiated precursors which is a process also termed as adipogenesis, drugs that might control adipogenesis could be beneficial for the treatment of obesity. In the current study, combined effect of sodium pentaborate pentahydrate (NaB) and pluronic F68 on adipogenic differentiation was examined by administering various combinations of the two agents to human adipose-derived stem cells (hADSCs) in in vitro. Immunocytochemistry and quantitative RT-PCR were performed to evaluate the levels of adipogenesis-promoting genes such as peroxisome proliferator-activated receptor-γ (PPARγ), fatty acid binding protein (FABP4), and adiponectin. Results indicated that expressions of all these three genes were restrained. Furthermore, Oil Red O staining revealed that lipid vesicle formation was reduced in hADSCs treated with differentiation medium containing NaB/F68 combination. Finally, expression levels of Hippo pathway kinases Lats2, MST1, and scaffold protein Sav1 were reduced in these cells, suggesting a possible link between Hippo pathway-dependent downregulation of PPARγ and the NaB/F68 treatment. Herein, we showed that combination of NaB and F68 curtails adipocyte differentiation by inhibiting the adipogenic transcriptional program leading to a decrease in lipid accumulation in adipocytes even at very low doses, thereby uncovered a striking opportunity to use this combination in obesity treatment.

Application of honey as a protective material in maintaining the viability of adipose stem cells in burn wound healing: A histological, molecular and biochemical study

Enhanced resistance to oxidative stress makes the adipose stem cells (ASCs) able to promote wound repair and regeneration. Such cells can be achieved by addition of an anti-oxidant to cell culture medium. In this study, a combination of honey (H) and ASCs was applied on burn wounds and the injured area was then covered by a tegaderm (T) dressing in a rat model. Wound healing was evaluated by histopathological, histomorphometrical, molecular, scanning electron microscopy, and biochemical assessments on days 7, 14, and 28 post-wounding. Treatment with ASCs-containing honey (T-H/ASC) resulted in substantial reduction in the level of pro-inflammatory cytokines including interleukin-1β (IL-1β) and transforming growth factor-β1 (TGF-β1) in wound bed, at 7 day post-surgery. T-H/ASCs also elevated the level of bFGF expression, indicating that ASCs enhanced angiogenesis, at 7 day post-wounding. T-H/ASCs significantly improved angiogenesis, re-epithelialization, and granulation tissue formation compared to other treatment regimes, at 14 day post-surgery. These outcomes were in exceptionally good agreement with the histological and biochemical findings. Increased bFGF level in the T-H/ASCs treated wounds at the 28th day post-surgery showed the anti-scarring activity of ASCs. Honey can be considered as a protective material in maintaining the viability of ASCs and improving the cellular resistance to oxidative stress. Furthermore, combination of ASCs and honey can provide a nutrient media for the ASCs and enhance the ability of regeneration of the ASC-based therapies.

Heterogeneity in Adipose Stem Cells

Adipose stem cells (ASCs) are the basis of procedures intended for tissue regeneration. These cells are heterogeneous, owing to various factors, including the donor age, sex, body mass index, and clinical condition; the isolation procedure (liposuction or fat excision); the place from where the cells were sampled (body site and depth of each adipose depot); culture surface; type of medium (whether supplemented with fetal bovine serum or xeno-free), that affect the principal phenotypic features of ASCs. The features related to ASCs heterogeneity are relevant for the success of therapeutic procedures; these features include proliferation capacity, differentiation potential, immunophenotype, and the secretome. These are important characteristics for the success of regenerative tissue engineering, not only because of their effects upon the reconstruction and healing exerted by ASCs themselves, but also because of the paracrine signaling of ASCs and its impact on recipient tissues. Knowledge of sources of heterogeneity will be helpful in the standardization of ASCs-based procedures. New avenues of research could include evaluation of the effects of the use of more homo1geneous ASCs for specific purposes, the study of ASCs-recipient interactions in heterologous cell transplantation, and the characterization of epigenetic changes in ASCs, as well as investigations of the effect of the metabolome upon ASCs behavior in culture.

Bone Morphogenetic Protein 2-Conjugated Silica Particles Enhanced Early Osteogenic Differentiation of Adipose Stem Cells on the Polycaprolactone Scaffold

Background

Silica particles (SPs) induce cell proliferation and osteogenic differentiation. We reported that SPs in the scaffold induced early stage osteogenic differentiation.

Methods

A polycaprolactone (PCL) scaffold was fabricated with a 10 wt% SPs. The surface of PCL scaffold was coated with a 10 µg/mL collagen solution. Next, the scaffold was conjugated with 2 μM SPs, 2 μg/mL bone morphogenetic protein 2 (BMP2), or 2 μM BMP2-conjugated SPs (BCSPs). Green fluorescent protein-coupled BMP2 was applied to fabricate the scaffold. The fluorescence intensity was analyzed by confocal microscopy. The mRNA levels of the early osteogenic differentiation marker, alkaline phosphatase (ALP), were analyzed by real-time quantitative polymerase chain reaction. Levels of BMP2, RUNX2, ERK1/2, and AKT were assessed by western blotting.

Results

ALP mRNA levels were significantly higher in the BCSP-conjugated scaffold than in the other scaffolds. In the early stage of osteogenic differentiation, the protein levels of BMP2, RUNX2, ERK1/2, and AKT in cells were significantly higher in the BCSP-conjugated scaffold than in other scaffolds. Thus, the BCSP composite scaffold induced rapid osteogenic differentiation.

Conclusion

These results suggest that BCSP composite can be used to promote early stage osteogenic differentiation and show promise as a material for use in scaffolds for bone regeneration.

Cyclic tensile stress promotes osteogenic differentiation of adipose stem cells via ERK and p38 pathways

The present study aimed to elucidate whether extracellular signal-regulated kinases 1/2 (ERK1/2) and p38 mitogen-activated protein kinases pathways participate in the transduction of mechanical stretch exerted on adipose stem cells (ASCs) into intracellular osteogenic signals, and if so whether both pathways have time-dependent feature. Rat ASCs were cultured in osteogenic medium for 72 h and assigned into three sets, namely ERK1/2 inhibitor treated set, p38 inhibitor treated set, and the control set. After inhibitor treatment, all cells were subjected to cyclic stretch(2000 με, 1 Hz) on a four-point bending mechanical loading device. Protein and mRNA samples were acquired at six time points: 0, 15 min, 30 min, 1 h, 2 h and 6 h. Western blot showed phosphorylation level of ERK1/2 was elevated by cyclic tensile stress at all time points, while p38 at 15 min, 30 min and 1 h, and the elevation can be completely blocked by corresponding inhibitors. The treatment by ERK1/2 inhibitor was shown to antagonize the up-regulation of osteogenic genes bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (Runx2) by mechanical stretch at 15 min and 6 h, whereas p38 inhibitor took effect at 15 min only. The results suggested both ERK and p38 could be positive mediators of stretch-induced osteogenic differentiation of ASCs, and ERK stimulate the stretch-induced osteogenic differentiation at both early and late stages while p38 responds to mechanical stretch in a more rapid fashion.

Healing potential of injectable Aloe vera hydrogel loaded by adipose-derived stem cell in skin tissue-engineering in a rat burn wound model

Adipose stem cells (ASCs) are a great promise in wound healing due to their potential in differentiating into various cell lineages and secreting growth factors. The purpose of this study is to evaluate the in vivo effects of Aloe vera hydrogel loaded by allogeneic ASCs on a rat burn wound model. The ASCs were isolated, cultured and mixed with 50% Aloe vera hydrogel and injected intradermally around the wound. Demineralized bone matrix (DBM) was used as dressing in the experiment. The burn wound-healing properties of different experimental groups were investigated by histopathological, molecular, scanning electron microscopic and biochemical analysis at the 7th, 14th and 28th days post-wounding. The Aloe vera and DBM-Aloe vera groups showed almost similar healing properties, while treatment by DBM-Aloe vera/ASCs significantly enhanced wound healing. The levels of transforming growth factor-β1 (TGF-β1) and interleukin-1β markedly decreased at the 7th day post-injury, in the DBM-Aloe vera/ASC-treated group, suggesting that this treatment regime subsided the inflammatory responses. Angiogenesis, re-epithelialization and the level of TGF-β1 in the wounds treated with DBM-Aloe vera/ASCs were also remarkably higher than those of other groups, at the 14th day post-injury. Besides, scar formation significantly decreased in the DBM-Aloe vera/ASC-treated wounds when compared with other groups. Our biochemical results were in agreement with the molecular and histopathological findings and strongly demonstrated that a DBM-Aloe vera/ASC composite can stimulate burn wound healing. These results suggest that the DBM-Aloe vera/ASC composite can be considered as a promising therapeutic strategy in the treatment of burn wounds.

Adenovirus type 36 regulates adipose stem cell differentiation and glucolipid metabolism through the PI3K/Akt/FoxO1/PPARγ signaling pathway

Background

This study aims to investigate the molecular mechanism of Adenovirus type 36 (Ad36) in adipocyte differentiation and glucolipid metabolism.

Methods

Rat obesity model was established by Ad36 infection and high-fat diet, respectively. Comparison of the body weight, clinical biochemical indicators, insulin sensitivity and lipid heterotopic deposition between these two models was performed. Ad36-induced adipocyte in vitro model was also established. The binding rate of FoxO1, PPARγ and its target gene promoter was detected using ChIP. The mRNA and protein expression levels of PPARγ and downstream target genes were detected by RT-PCR and Western blot, respectively. Oil red O staining was used to measure differentiation into adipocyte. Wortmannin (WM), inhibitor of PI3K, was used to act on Ad36-induced hADSCs.

Results

Ad36-induced obese rats did not exhibit disorders in blood glucose and blood TG, insulin resistance and lipid ectopic deposition. The expression of Adipoq, Lpin1 and Glut4 in the adipose tissue increased. Oil red O staining showed that Ad36 induced the differentiation of hAMSCs into human adipocytes in vitro. During this process, the binding rate of FoxO1 and PPARγ promoter regions was weakened. However, the binding rate of the transcription factor PPARγ to its target genes Acc, Adipoq, Lpin1 and Glut4 was enhanced, and thus increased the protein expression of P-FoxO1, PPARγ2, ACC, LPIN1, GLUT4 and ADIPOQ. The PI3K inhibitor Wortmannin reduced the expression of P-Akt, P-FoxO1 and PPARγ2, thereby inhibiting adipogenesis of hADSC.

Conclusion

Ad36 may promote fatty acid and triglyceride synthesis, and improve insulin sensitivity by affecting the PI3K/Akt/FoxO1/PPARγ signaling pathway.

Bioactive glass ions induce efficient osteogenic differentiation of human adipose stem cells encapsulated in gellan gum and collagen type I hydrogels

BACKGROUND

Due to unmet need for bone augmentation, our aim was to promote osteogenic differentiation of human adipose stem cells (hASCs) encapsulated in gellan gum (GG) or collagen type I (COL) hydrogels with bioactive glass (experimental glass 2-06 of composition [wt-%]: Na₂O 12.1, K₂O 14.0, CaO 19.8, P₂O5 2.5, B₂O₃ 1.6, SiO₂ 50.0) extract based osteogenic medium (BaG OM) for bone construct development. GG hydrogels were crosslinked with spermidine (GG-SPD) or BaG extract (GG-BaG).

METHODS

Mechanical properties of cell-free GG-SPD, GG-BaG, and COL hydrogels were tested in osteogenic medium (OM) or BaG OM at 0, 14, and 21 d. Hydrogel embedded hASCs were cultured in OM or BaG OM for 3, 14, and 21 d, and analyzed for viability, cell number, osteogenic gene expression, osteocalcin production, and mineralization. Hydroxyapatite-stained GG-SPD samples were imaged with Optical Projection Tomography (OPT) and Selective Plane Illumination Microscopy (SPIM) in OM and BaG OM at 21 d. Furthermore, Raman spectroscopy was used to study the calcium phosphate (CaP) content of hASC-secreted ECM in GG-SPD, GG-BaG, and COL at 21 d in BaG OM.

RESULTS

The results showed viable rounded cells in GG whereas hASCs were elongated in COL. Importantly, BaG OM induced significantly higher cell number and higher osteogenic gene expression in COL. In both hydrogels, BaG OM induced strong mineralization confirmed as CaP by Raman spectroscopy and significantly improved mechanical properties. GG-BaG hydrogels rescued hASC mineralization in OM. OPT and SPIM showed homogeneous 3D cell distribution with strong mineralization in BaG OM. Also, strong osteocalcin production was visible in COL.

CONCLUSIONS

Overall, we showed efficacious osteogenesis of hASCs in 3D hydrogels with BaG OM with potential for bone-like grafts.

Higher Pericyte Content and Secretory Activity of Microfragmented Human Adipose Tissue Compared to Enzymatically Derived Stromal Vascular Fraction

Autologous adipose tissue is used for tissue repletion and/or regeneration as an intact lipoaspirate or as enzymatically derived stromal vascular fraction (SVF), which may be first cultured into mesenchymal stem cells (MSCs). Alternatively, transplant of autologous adipose tissue mechanically fragmented into submillimeter clusters has recently showed remarkable efficacy in diverse therapeutic indications. To document the biologic basis of the regenerative potential of microfragmented adipose tissue, we first analyzed the distribution of perivascular presumptive MSCs in adipose tissue processed with the Lipogems technology, observing a significant enrichment in pericytes, at the expense of adventitial cells, as compared to isogenic enzymatically processed lipoaspirates. The importance of MSCs as trophic and immunomodulatory cells, due to the secretion of specific factors, has been described. Therefore, we investigated protein secretion by cultured adipose tissue clusters or enzymatically derived SVF using secretome arrays. In culture, microfragmented adipose tissue releases many more growth factors and cytokines involved in tissue repair and regeneration, noticeably via angiogenesis, compared to isogenic SVF. Therefore, we suggest that the efficient tissue repair/regeneration observed after transplantation of microfragmented adipose tissue is due to the secretory ability of the intact perivascular niche. Stem Cells Translational Medicine 2018;7:876-886.

An Investigation on the Regenerative Effects of Intra Articular Injection of Co-Cultured Adipose Derived Stem Cells with Chondron for Treatment of Induced Osteoarthritis

Purpose: Adipose tissue derived stem cells (ASCs) and chondrocytes are best cells for articular cartilage regeneration. Chondrocyte with peri-cellular matrix (PCM) is called chondron provides ideal microenviroment than chondrocytes. We aimed to evaluate the regenerative effects of intra-articular injection of ASCs co-cultures with chondron in induced osteoarthritis (OA).

Methods: ASC, from the peri-renal fat of male rat and chondron from primary newborn rat hyaline cartilage were isolated. ASCs were cultured for at least three passages in vitro. Six weeks after OA induction, rats were randomly distributed in five groups of control, osteoarthritic, ASC, chondron and co-cultured. ASCs (10⁷), chondrons (10⁷) and combination of chondrons and ASCs (10⁷) were injected into intra-articular space of the rat knee. The effect of treatments was evaluated by macroscopic and microscopic examinations. The expression levels of collagen type ΙΙ was studied by immunohistochemistry.

Results: Macroscopic appearance of the co-cultured group, showed much enhanced articular cartilage regeneration compared to ASC and chondron groups. H&E showed evidence of repair site of articular surface without erosion and fibrillation versus OA group which showed thin layer of hyaline cartilage over tidemark and spontaneous fibrocartilage formation. Metachromatic regions stained with toluidine blue were larger in treatment groups versus OA group. Strong intensity of type ΙΙ collagen staining was observed in co-culture group compared to other groups.

Conclusion: Co-culture of chondrons and ASCs increased articular hyaline cartilage formation and provides a useful tool to improve limitations of each of applied cells in this model.

Adipose stem cells enhance excisional wound healing in a porcine model

BACKGROUND

Adipose-derived stem cells (ASCs) are capable of secreting regenerative growth factors and replacing multiple tissue types. Although current literature suggests that ASCs accelerate wound healing and reduce scarring, the dose-response relationship has not been adequately investigated in large animals. We sought to establish a porcine model to optimize dose and delivery.

METHODS

Four-centimeter circular, full thickness excisional wounds were created on the backs of Yorkshire pigs. Fluorescently labeled allogeneic porcine ASCs were injected into the superficial wound bed and around the wound perimeter at high (3.0 × 10⁶ cells/cm²; n = 8), medium (1.0 × 10⁶ cells/cm²; n = 8), and low (0.3 × 10⁶ cells/cm²; n = 8) doses. Control wounds received saline injections (n = 8) or no treatment (n = 8). Dressings were changed twice per week, and wound closure was tracked by surface area tracing. Animals were sacrificed at 1 and 2 wk. Wounds were harvested for real-time quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry, and ASC tracking.

RESULTS

Labeled ASCs integrated into treated wounds by 1 wk in a dose-dependent fashion. Epithelial coverage was achieved by 14 d in all wounds. Wounds receiving high-dose ASCs exhibited thicker granulating neodermis at 7 d and greater wound contraction at 14 d. real-time quantitative reverse transcriptase polymerase chain reaction revealed improved collagen 1:collagen 3 (Col1:Col3) ratio in the medium-dose group and enhanced α-smooth muscle actin in the high-dose group at 14 d. Western blot demonstrated increased cluster of differentiation 31 protein at 2 wk in wounds receiving >10⁶ cells/cm².

CONCLUSIONS

Doses up to 3.0 × 10⁶ cells/cm² were well-tolerated. High-dose ASCs accelerate wound contraction, enhance neovascularization, and may improve scar quality in excisional wounds healing by secondary intention. Doses greater than those previously used may be necessary to achieve desired effects.

Adipose Stem Cells with Conditioned Media for Treatment of Acne Vulgaris Scar

This study was to investigate the effect of subcutaneous injection of the adipose stem cells (ASCs) with conditioned media (CM) in the treatment of acne vulgaris scar. We used Adult male New Zealand white rabbit ears as an animal model and induced acne formation by Kignman method. Adipose tissue was isolated and harvested from the scapula of rabbits, and ASCs were cultured and expanded until passage 1. There have four groups in our experiment, include phosphate buffered saline (PBS), ASCs with PBS (ASC + PBS), CM, and ASCs with CM (ASC + CM) group. This solution of 0.6 ml injected to subcutaneous in each group. ASC + PBS and ASC + CM groups were containing ASCs of 5.0 × 106 cells/ml. We analyzed the treatment of 4 groups to scar tissue after 2 and 4 weeks by hematoxylin and eosin stain, immunohistochemistry, and RNA expression level of tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), and matrix metalloproteinase-2 (MMP-2). Also, the expression of keratin 16 (K16) was detected by western blot analysis. H&E stain showed that infiltration of inflammation cells was significantly reduced at 2 and 4 weeks, as well as re-epithelialization was improved in the ASC + CM group. The ASC + CM gourp was reduced both expression levels of TNF-α, IL-1α, and MMP-2 and K16 protein level. In conclusion, the ASCs with CM has a significant curative effect on acne vulgaris scar, more to the point, the CM has a key role on treatment. It could be applied to a therapeutic approach to regenerate to treat acne vulgaris scar.

Functional recovery by application of human dedifferentiated fat cells on cerebral infarction mice model

Elderly people whose daily activities have declined due to a cerebrovascular disorder may suffer from dysphagia and may find oral hygiene difficult. Therefore, it is important to establish an effective therapy for the underlying cerebrovascular disorder. Dedifferentiated fat cells (DFAT) were obtained from mature adipocytes isolated from human buccal adipose pads in a ceiling culture. DFAT expressed the neural markers Nestin and SOX2. Flow cytometric analysis revealed that the cells had properties similar to mesenchymal stem cells. Although the transplantation of DFAT did not change the infarction area and volume ratios in a murine cerebral infarction model, functional recovery was observed in behavioral tests. Furthermore, DFAT administered to mice were later detected in cerebral infarctions. It therefore appears that transplanted DFAT affect the brain after infarction and contribute to the promotion of functional recovery. This finding may provide new cell replacement therapy options for treating disorders of the central nervous system.

Novel layered double hydroxides-hydroxyapatite/gelatin bone tissue engineering scaffolds: Fabrication, characterization, and in vivo study

Developing porous biodegradable scaffolds through simple methods is one of the main approaches of bone tissue engineering (BTE). In this work, a novel BTE composite containing layered double hydroxides (LDH), hydroxyapatite (HA) and gelatin (GEL) was fabricated using co-precipitation and solvent-casting methods. Physiochemical characterizations showed that the chemical composition and microstructure of the scaffolds were similar to the natural spongy bone. Interconnected macropores ranging over 100 to 600μm were observed for both scaffolds while the porosity of 90±0.12% and 92.11±0.15%, as well as, Young's modulus of 19.8±0.41 and 12.5±0.35GPa were reported for LDH/GEL and LDH-HA/GEL scaffolds, respectively. The scaffolds were degraded in deionized water after a month. The SEM images revealed that between two scaffolds, the LDH-HA/GEL with needle-like secondary HA crystals showed better bioactivity. According to the alkaline phosphatase activity and Alizarin red staining results, LDH-HA/GEL scaffolds demonstrated better bone-specific activities comparing to LDH/Gel scaffold as well as control sample (P<0.05). The rabbit adipose stem cells (ASCs) were extracted and cultured, then seeded on the LDH-HA/GEL scaffolds after confluence. Three groups of six adult rabbits were prepared: the scaffold+ASCs group, the empty scaffold group and the control group. The critical defects were made on the left radius and the scaffolds with or without ASCs were implanted there while the control group was left without any treatment. All animals were sacrificed after 12weeks. Histomorphometric results showed that the regeneration of defects was accelerated by scaffold implantation but ASC-seeding significantly improved the quality of new bone formation (P<0.05). The results confirmed the good performance of LDH-HA/GEL scaffold to induce bone regeneration.

Chemical group-dependent plasma polymerisation preferentially directs adipose stem cell differentiation towards osteogenic or chondrogenic lineages

Human adipose derived stem cells (ADSCs) are being explored for the repair of craniofacial defects due to their multi-differentiation potential and ease of isolation and expansion. Crucial to using ADSCs for craniofacial repair is the availability of materials with appropriate biomechanical properties that can support their differentiation into bone and cartilage. We tested the hypothesis that different modifications of chemical groups on the surface of a nanocomposite polymer could increase human ADSC adhesion and selectively enhance their osteogenic and chondrogenic differentiation. We show that the COOH modification significantly promoted initial cell adhesion and proliferation over 14 days compared to NH₂ surfaces. Expression of focal adhesion kinase and vinculin was enhanced after plasma surface polymerisation at 24 h. The COOH modification significantly enhanced chondrogenic differentiation as indicated by up-regulation of aggrecan and collagen II transcripts. In contrast, NH₂ group functionalised scaffolds promoted osteogenic differentiation with significantly enhanced expression of collagen I, alkaline phosphatase and osteocalcin both at the gene and protein level. Finally, chorioallantoic membrane grafting demonstrated that both NH₂ and COOH functionalised scaffolds seeded with ADSCs were biocompatible and supported vessel ingrowth apparently to a greater degree than unmodified scaffolds. In summary, our study shows the ability to direct ADSC chondrogenic and osteogenic differentiation by deposition of different chemical groups through plasma surface polymerisation. Hence this approach could be used to selectively enhance bone or cartilage formation before implantation in vivo to repair skeletal defects.

Statement of Significance

Human adipose derived stem cells (hADSCs) are an exciting stem cell source for regenerative medicine due to their plentiful supply and ease of isolation. However, the optimal environmental cues to direct stem cells towards certain lineages change have to has not been identified. We have shown that by modifying the surface of the scaffold with specific chemical groups using plasma surface polymerisation techniques we can control ADSCs differentiation. This study shows that ADSCs can be differentiated towards osteogenic and chondrogenic lineages on amine (NH₂) and carboxyl (COOH) modified scaffolds respectively. Plasma polymerisation can be easily applied to other biomaterial surfaces to direct stem cell differentiation for the regeneration of bone and cartilage.

Culture supernatant of adipose stem cells can ameliorate allergic airway inflammation via recruitment of CD4+CD25+Foxp3 T cells

Background

In a previous study, we demonstrated that intravenous administration of adipose tissue stem cells (ASCs) could significantly reduce allergic symptoms and suppress eosinophilic inflammation.

Methods

To evaluate the secretome of ASCs, we administrated culture supernatant of ASCs (ASC sup, which contains the ASC secretome) and uncultured fresh medium (con sup) into a mouse model of allergic airway inflammation. Subsequently we observed the mice for signs of inflammation and investigated Th1-, Th2-, and T_reg-related cytokine levels as well as recruitment of T_reg cells into the airway.

Results

We found that ASC sup could ameliorate allergic airway inflammation in this model; the value of airway hyperresponsiveness, and the occurrence of inflammatory cell infiltration in the lung, as well as the number of eosinophils, and goblet cells in the lung epithelium were all significantly decreased by ASC sup treatment. In addition, ASC sup treatment significantly decreased the levels of IL-4, IL-5, and IL-13 in the bronchial alveolar lavage fluid and in culture medium of lung-draining lymph node cells of the animal model of acute asthma. We detected numerous CTLA-4 and Foxp3-expressing cells in the lung after ASC sup treatment. ASC sup was found to have a higher concentration of IL-10 and TGF-β compared to con sup.

Conclusions

Stem cells have powerful potential for therapeutic functions in various diseases, but they also have many drawbacks. In this study, we found strong immunosuppressive ability of ASC sup in an allergic airway mouse model. It may be possible to use ASC sup for treatment of many immunological diseases in the near future.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0462-5) contains supplementary material, which is available to authorized users.

Involvement of cAMP in the Human Serum-Induced Migration of Adipose-Derived Stem Cells

Previously we observed that human adipose-derived stem cells (hADSCs) could form aggregation during culture in the presence of human serum (HS). In the present study, we have examined if the aggregation might result from the cell migration and analyzed the difference of cell adhesivity after culture in various conditions. When cells were cultured in fetal bovine serum (FBS) alone, there was no morphological change. Similarly, cells pretreated with FBS for 1 day or cultured in a mixture of FBS and HS showed little change. In contrast, cells cultured in HS alone exhibited formation of cell-free area (spacing) and/or cell aggregation. When cells cultured in FBS or pretreated with FBS were treated with 0.06% trypsin, almost cells remained attached to the dish surfaces. In contrast, when cells cultured in HS alone were examined, most cells detached from the dish by the same treatment. Treatment of cells with forskolin, isobutylmethyl xanthine (IBMX) or LY294002 inhibited the formation of spacing whereas H89 or Y27632 showed little effect. When these cells were treated with 0.06% trypsin after culture, most cells detached from the dishes as cells cultured in HS alone did. However, cells treated with IBMX exhibited weaker adhesivity than HS alone. Based on these observations, it is suggested that HS treatment might decrease the adhesivity and induce three-dimensional migration of hADSCs, in the latter of which cAMP signaling could be involved.

Identification of suitable reference genes for quantitative gene expression analysis in rat adipose stromal cells induced to trilineage differentiation

This study was designed to (i) identify stable reference genes for the analysis of gene expression during in vitro differentiation of rat adipose stromal cells (rASCs), (ii) recommend stable genes for individual treatment conditions, and (iii) validate these genes by comparison with normalization results from stable and unstable reference genes. On the basis of a literature review, eight genes were selected: Actb, B2m, Hprt1, Ppia, Rplp0, Rpl13a, Rpl5, and Ywhaz. Genes were ranked according to their stability under different culture conditions as assessed using GenNorm, NormFinder, and RefFinder algorithms. Although the employed algorithms returned different rankings, the most frequently top-ranked genes were: B2m and/or Ppia for all 28day treatments (ALL28); Ppia and Hprt1 (adipogenic differentiation; A28), B2m (chondrogenic differentiation; C28), Rpl5 (controls maintained in complete culture medium; CCM), Rplp0 (osteogenic differentiation for 3days; O3), Rpl13a and Actb (osteogenic differentiation for 7days; O7), Rplp0 and Ppia (osteogenic differentiation for 14days; O14), Hprt1 and Ppia (osteogenic differentiation for 28days; O28), as well as Actb (all osteogenesis time points combined; ALLOSTEO). The obtained results indicate that the performance of reference genes depends on the differentiation protocol and on the analysis time, thus providing valuable information for the design of RT-PCR experiments.

Long-acting insulin analog detemir displays reduced effects on adipocyte differentiation of human subcutaneous and visceral adipose stem cells

BACKGROUND AND AIMS

Since treatment with insulin detemir results in a lower weight gain compared to human insulin, we investigated whether detemir is associated with lower ability to promote adipogenesis and/or lipogenesis in human adipose stem cells (ASC).

METHODS AND RESULTS

Human ASC isolated from both the subcutaneous and visceral adipose tissues were differentiated for 30 days in the presence of human insulin or insulin detemir. Nile Red and Oil-Red-O staining were used to quantify the rate of ASC conversion to adipocytes and lipid accumulation, respectively. mRNA expression levels of early genes, including Fos and Cebpb, as well as of lipogenic and adipogenic genes, were measured at various phases of differentiation by qRT-PCR. Activation of insulin signaling was assessed by immunoblotting. ASC isolated from subcutaneous and visceral adipose tissue were less differentiated when exposed to insulin detemir compared to human insulin, showing lower rates of adipocyte conversion, reduced triglyceride accumulation, and impaired expression of late-phase adipocyte marker genes, such as Pparg2, Slc2a4, Adipoq, and Cidec. However, no differences in activation of insulin receptor, Akt and Erk and induction of the early genes Fos and Cebpb were observed between insulin detemir and human insulin.

CONCLUSION

Insulin detemir displays reduced induction of the Pparg2 adipocyte master gene and diminished effects on adipocyte differentiation and lipogenesis in human subcutaneous and visceral ASC, in spite of normal activation of proximal insulin signaling reactions. These characteristics of insulin detemir may be of potential relevance to its weight-sparing effects observed in the clinical setting.

Adipose-Derived Stem Cells Induce Angiogenesis via Microvesicle Transport of miRNA-31

Cell secretion is an important mechanism for stem cell-based therapeutic angiogenesis, along with cell differentiation to vascular endothelial cells or smooth muscle cells. Cell-released microvesicles (MVs) have been recently implicated to play an essential role in intercellular communication. The purpose of this study was to explore the potential effects of stem cell-released MVs in proangiogenic therapy. We observed for the first time that MVs were released from adipose-derived stem cells (ASCs) and were able to increase the migration and tube formation of human umbilical vein endothelial cells (HUVECs). Endothelial differentiation medium (EDM) preconditioning of ASCs upregulated the release of MVs and enhanced the angiogenic effect of the released MVs in vitro. RNA analysis revealed that microRNA was enriched in ASC-released MVs and that the level of microRNA-31 (miR-31) in MVs was notably elevated upon EDM-preconditioning of MV-donor ASCs. Further studies exhibited that miR-31 in MVs contributed to the migration and tube formation of HUVECs, microvessel outgrowth of mouse aortic rings, and vascular formation of mouse Matrigel plugs. Moreover, factor-inhibiting HIF-1, an antiangiogenic gene, was identified as the target of miR-31 in HUVECs. Our findings provide the first evidence that MVs from ASCs, particularly from EDM-preconditioned ASCs, promote angiogenesis and the delivery of miR-31 may contribute the proangiogenic effect.

SIGNIFICANCE

This study provides the evidence that microvesicles (MVs) from adipose-derived stem cells (ASCs), particularly from endothelial differentiation medium (EDM)-preconditioned ASCs, promote angiogenesis. An underlying mechanism of the proangiogenesis may be the delivery of microRNA-31 via MVs from ASCs to vascular endothelial cells in which factor-inhibiting HIF-1 is targeted and suppressed. The study findings reveal the role of MVs in mediating ASC-induced angiogenesis and suggest a potential MV-based angiogenic therapy for ischemic diseases.

The Antiaging Gene Klotho Regulates Proliferation and Differentiation of Adipose-Derived Stem Cells

Klotho was originally discovered as an aging-suppressor gene. The purpose of this study was to investigate whether secreted Klotho (SKL) affects the proliferation and differentiation of adipose-derived stem cells (ADSCs). RT-PCR and Western blot analysis showed that short-form Klotho was expressed in mouse ADSCs. The Klotho gene mutation KL(-/-) significantly decreased proliferation of ADSCs and expression of pluripotent transcription factors (Nanog, Sox-2, and Oct-4) in mice. The adipogenic differentiation of ADSCs was also decreased in KL(-/-) mice. Incubation with Klotho-deficient medium decreased ADSC proliferation, pluripotent transcription factor levels, and adipogenic differentiation, which is similar to what was found in KL(-/-) mice. These results indicate that Klotho deficiency suppresses ADSC proliferation and differentiation. Interestingly, treatment with recombinant SKL protein rescued the Klotho deficiency-induced impairment in ADSC proliferation and adipogenic differentiation. SKL also regulated ADSCs' differentiation to other cell lineages (osteoblasts, myofibroblasts), indicating that SKL maintains stemness of ADSCs. It is intriguing that overexpression of SKL significantly increased PPAR-γ expression and lipid formation in ADSCs following adipogenic induction, indicating enhanced adipogenic differentiation. Overexpression of SKL inhibited expression of TGFβ1 and its downstream signaling mediator Smad2/3. This study demonstrates, for the first time, that SKL is essential to the maintenance of normal proliferation and differentiation in ADSCs. Klotho regulates adipogenic differentiation in ADSCs, likely via inhibition of TGFβ1 and activation of PPAR-γ. Stem Cells 2016;34:1615-1625.

Bone Morphogenetic Protein-2 Induces Donor-Dependent Osteogenic and Adipogenic Differentiation in Human Adipose Stem Cells

Bone morphogenetic protein-2 (BMP-2) is a growth factor used to stimulate bone regeneration in clinical applications. However, there are contradicting reports on the functionality of BMP-2 in human adipose stem cells (hASCs), which are frequently used in tissue engineering. In this study, we analyzed the effects of BMP-2 on SMAD1/5 signaling, proliferation, and differentiation in hASCs. Our results indicated that BMP-2 induced dose-dependent (25-100 ng/ml) activation of SMAD signaling. Furthermore, the cell proliferation analysis revealed that BMP-2 (100 ng/ml) consistently decreased the proliferation in all the cell lines studied. However, the analysis of the differentiation potential revealed that BMP-2 (100 ng/ml) exhibited a donor-dependent dual role, inducing both osteogenic and adipogenic differentiation in hASCs. The quantitative alkaline phosphatase (qALP) activity and mineralization levels were clearly enhanced in particular donor cell lines by BMP-2 stimulus. On the contrary, in other cell lines, qALP and mineralization levels were diminished and the lipid formation was enhanced. The current study also suggests that hASCs have accelerated biochemical responsiveness to BMP-2 stimulus in human serum-supplemented culture medium compared with fetal bovine serum. The production origin of the BMP-2 growth factor is also important for its response: BMP-2 produced in mammalian cells enhanced signaling and differentiation responses compared with BMP-2 produced in Escherichia coli. These results explain the existing contradiction in the reported BMP-2 studies and indicate the variability in the functional end mechanism of BMP-2-stimulated hASCs.

SIGNIFICANCE

This study examined how bone morphogenetic protein-2 (BMP-2) modulates the SMAD signaling mechanism and the proliferation and differentiation outcome of human adipose stem cells (hASCs) derived from several donors. The results indicate that BMP-2 triggers molecular SMAD signaling mechanisms in hASCs and regulates differentiation processes in human serum-culture conditions. Importantly, BMP-2 has dual activity, inducing osteogenic and adipogenic differentiation, subject to hASC donor line studied. These findings explain contradictory previous results and highlight the importance of further studies to understand how signaling pathways guide mesenchymal stem cell functions at the molecular level.

Epigenetic priming of inflammatory response genes by high glucose in adipose progenitor cells

Cellular metabolism confers wide-spread epigenetic modifications required for regulation of transcriptional networks that determine cellular states. Mesenchymal stromal cells are responsive to metabolic cues including circulating glucose levels and modulate inflammatory responses. We show here that long term exposure of undifferentiated human adipose tissue stromal cells (ASCs) to high glucose upregulates a subset of inflammation response (IR) genes and alters their promoter histone methylation patterns in a manner consistent with transcriptional de-repression. Modeling of chromatin states from combinations of histone modifications in nearly 500 IR genes unveil three overarching chromatin configurations reflecting repressive, active, and potentially active states in promoter and enhancer elements. Accordingly, we show that adipogenic differentiation in high glucose predominantly upregulates IR genes. Our results indicate that elevated extracellular glucose levels sensitize in ASCs an IR gene expression program which is exacerbated during adipocyte differentiation. We propose that high glucose exposure conveys an epigenetic 'priming' of IR genes, favoring a transcriptional inflammatory response upon adipogenic stimulation. Chromatin alterations at IR genes by high glucose exposure may play a role in the etiology of metabolic diseases.

Transcription outcome of promoters enriched in histone variant H3.3 defined by positioning of H3.3 and local chromatin marks

Replication-independent histone variant H3.3 is incorporated into distinct genomic regions including promoters. However topology of promoter-associated H3.3 in relation to chromatin modifications and transcriptional outcome is not known, providing no insight on any distinction between H3.3-containing active and inactive promoters. Here, we report algorithms providing information on gene expression status as a function of density and position of multiple chromatin marks on promoters. We identify a relationship between promoter enrichment in epitope-tagged H3.3 or its canonical isoform H3.2 and corresponding transcriptional outcomes, as a function of sub-promoter positioning of DNA methylation and H3K4me3, H3K9me3 and H3K27me3. We identify a low-frequency configuration of H3.3 and H3K9me3 co-occupancy associated with transcriptional activity, while H3.3 and H3K27me3 promoters are invariably inactive. We unveil H3.3 and DNA methylated promoters whose transcription outcome depends on H3.3 sub-promoter positioning. Our results indicate how spatially restricted positioning of H3.3 may add another layer of transcription regulation.

Porous membrane with reverse gradients of PDGF-BB and BMP-2 for tendon-to-bone repair: in vitro evaluation on adipose-derived stem cell differentiation

Polycaprolactone (PCL)/Pluronic F127 membrane with reverse gradients of dual platelet-derived growth factor-β (PDGF-BB) and bone morphogenetic protein 2 (BMP-2) concentrations was fabricated using a diffusion method to investigate the effect of reverse gradients of dual growth factor concentrations on adipose-derived stem cell (ASC) differentiations, such as tenogenesis and osteogenesis. The PDGF-BB and BMP-2 were continuously released from the membrane for up to 35 days, with reversely increasing/decreasing growth factors along the membrane length. Human ASCs were seeded on the membrane with reverse PDGF-BB and BMP-2 gradients. The cells were confluent after 1 week of culture, regardless of growth factor types or concentrations on the membrane. Gene expression (real-time polymerase chain reaction), Western blot and immunohistological analyses after 1 and 2 weeks of ASC culture showed that the membrane sections with higher PDGF-BB and lower BMP-2 concentrations provided a better environment for ASC tenogenesis, while the membrane sections with higher BMP-2 and lower PDGF-BB concentrations were better for promoting osteogenesis. The results suggest that the membrane with reverse gradients of PDGF-BB and BMP-2 may be promising for tendon-to-bone repair, as most essential biological processes are mediated by gradients of biological molecules in the body.

Optimizing a novel method for low intensity ultrasound in chondrogenesis induction

BACKGROUND

Hyaline cartilage tissue of joints is susceptible to injuries due to avascularity. Mesenchymal stem cells (MSCs) are used for cartilage tissue engineering. Among MSCs, adipose stem cells (ASCs) are attractive because of accessibility, their large number, and rapid growth. Common in vitro protocols successfully induce chondrogenic differentiation by expression of multiple cartilage-specific molecules. However, transforming growth factor β (TGFβ) promotes chondrogenesis to terminal stages. Despite much attention being given to the influences of biochemical factors on chondrogenesis of MSCs, few studies have examined the chondrogenic effect of mechanical factors such as ultrasound as a feasible tool.

MATERIALS AND METHODS

In this study, we focused on inducing chondrogenesis in the early stages of differentiation by using low-intensity ultrasound (LIUS). Four groups of ASC pellets (control, ultrasound, TGFβ, and ultrasound/TGF) were cultured under chondrogenic (10 ng/ml of TGFβ3) and ultrasound conditions (200 mW/cm(2), 10 min/day). After 2 weeks, differentiation was evaluated by histology, quantitative gene expression analysis, and immunohistochemistry.

RESULTS

Our data demonstrated that ultrasound differentiated pellets showed increased expression of early chondrogenesis marker, Col2A, than those in TGFβ groups (P < 0.001), and Col2B and Col10 expression were more prominent in TGFβ groups. Immunostaining of sections showed Col2 fibrils around lacuna in LIUS and TGFβ treated groups.

CONCLUSION

Using LIUS resulted in early chondrogenesis in comparison with terminally differentiated chondrocytes by TGFβ. Therefore, LIUS might provide an applicable, safe, efficient, and cheap tool for chondrogenic differentiation of ASCs in cartilage tissue engineering.