Adipose-derived stem cells were impaired in restricting CD4+T cell proliferation and polarization in type 2 diabetic ApoE-/- mouse

Application of adipose tissue-derived stem cell therapy with a clinically relevant dose does not significantly affect atherosclerotic plaque characteristics in a streptozotocin-induced hyperglycaemia mouse model

Aims

Diabetes mellitus (DM) induces increased inflammation of atherosclerotic plaques, resulting in elevated plaque instability. Mesenchymal stem cell (MSC) therapy was shown to decrease plaque size and increase stability in non-DM animal models. We now studied the effect of MSC therapy in a streptozotocin-induced hyperglycaemia mouse model using a clinically relevant dose of adipose tissue-derived MSCs (ASCs).

Methods

Hyperglycaemia was induced in male C57BL/6 ApoE-/- mice (n=24) via intraperitoneal streptozotocin (STZ) injection (0.05 mg/g bodyweight) for 5 consecutive days. 16 weeks after the first STZ injection, the mice received either 100,000 ASCs (n=9) or vehicle (n=14) intravenously. The effects of ASC treatment on the size and stability of aortic root atherosclerotic plaques were determined 4 weeks post-treatment via (immuno)histochemical analyses. Furthermore, plasma monocyte subsets within 3 days pre- and 3 days post-treatment, and 4 weeks post-treatment, were studied.

Results

ASC treatment did not significantly affect atherosclerotic plaque size or intra-plaque inflammation. Although ASC-treated mice had a higher percentage of intra-plaque fibrosis (42.5±3.3%) compared to vehicle-treated mice (37.6±6.8%, p=0.07), this did not reach significance. Additionally, although differences in the percentages of circulating pro- and anti-inflammatory monocytes were observed after ASC treatment compared to pre-treatment (p=0.005), their levels did not differ significantly at any time point compared to vehicle-treated mice.

Conclusions

ASC treatment with a clinically relevant dose did not significantly affect atherosclerotic plaque size or intra-plaque inflammation in a hyperglycaemia mouse model. Despite a borderline significant improvement in intraplaque fibrotic content, the potential of ASC treatment on atherosclerotic plaque stability in a diabetic environment remains to be determined.

Aging and Metabolic Reprogramming of Adipose-Derived Stem Cells Affect Molecular Mechanisms Related to Cardiovascular Diseases

We performed a systematic search of the PubMed database for English-language articles related to the function of adipose-derived stem cells in the pathogenesis of cardiovascular diseases. In preclinical models, adipose-derived stem cells protected arteries and the heart from oxidative stress and inflammation and preserved angiogenesis. However, clinical trials did not reiterate successful treatments with these cells in preclinical models. The low success in patients may be due to aging and metabolic reprogramming associated with the loss of proliferation capacity and increased senescence of stem cells, loss of mitochondrial function, increased oxidative stress and inflammation, and adipogenesis with increased lipid deposition associated with the low potential to induce endothelial cell function and angiogenesis, cardiomyocyte survival, and restore heart function. Then, we identify noncoding RNAs that may be mechanistically related to these dysfunctions of human adipose-derived stem cells. In particular, a decrease in let-7, miR-17-92, miR-21, miR-145, and miR-221 led to the loss of their function with obesity, type 2 diabetes, oxidative stress, and inflammation. An increase in miR-34a, miR-486-5p, and mir-24-3p contributed to the loss of function, with a noteworthy increase in miR-34a with age. In contrast, miR-146a and miR-210 may protect stem cells. However, a systematic analysis of other noncoding RNAs in human adipose-derived stem cells is warranted. Overall, this review gives insight into modes to improve the functionality of human adipose-derived stem cells.

Single-cell RNA sequencing of subcutaneous adipose tissues identifies therapeutic targets for cancer-associated lymphedema

Cancer-associated lymphedema frequently occurs following lymph node resection for cancer treatment. However, we still lack effective targeted medical therapies for the treatment or prevention of this complication. An in-depth elucidation of the cellular alterations in subcutaneous adipose tissues of lymphedema is essential for medical development. We performed single-cell RNA sequencing of 70,209 cells of the stromal vascular fraction of adipose tissues from lymphedema patients and healthy donors. Four subpopulations of adipose-derived stromal cells (ASCs) were identified. Among them, the PRG4⁺/CLEC3B⁺ ASC subpopulation c3 was significantly expanded in lymphedema and related to adipose tissue fibrosis. Knockdown of CLEC3B in vitro could significantly attenuate the fibrogenesis of ASCs from patients. Adipose tissues of lymphedema displayed a striking depletion of LYVE⁺ anti-inflammatory macrophages and exhibited a pro-inflammatory microenvironment. Pharmacological blockage of Trem1, an immune receptor predominantly expressed by the pro-inflammatory macrophages, using murine LR12, a dodecapeptide, could significantly alleviate lymphedema in a mouse tail model. Cell–cell communication analysis uncovered a perivascular ligand-receptor interaction module among ASCs, macrophages, and vascular endothelial cells. We provided a comprehensive analysis of the lineage–specific changes in the adipose tissues from lymphedema patients at a single-cell resolution. CLEC3B was found to be a potential target for alleviating adipose tissue fibrosis. Pharmacological blockage of TREM1 using LR12 could serve as a promising medical therapy for treating lymphedema.

D4F alleviates the C/EBP homologous protein-mediated apoptosis in glycated high-density lipoprotein-treated macrophages by facilitating autophagy

The present study aimed to investigate the role of D4F, an apolipoprotein A-I mimetic peptide, in macrophage apoptosis induced by the glycated high-density lipoprotein (gly-HDL)-induced endoplasmic reticulum (ER) stress C/EBP homologous protein (CHOP) pathway, and unravel the regulatory role of autophagy in this process. Our results revealed that except for suppressing the accumulation of lipids within RAW264.7 macrophages caused by gly-HDL, D4F inhibited gly-HDL-induced decrease in the cell viability and increase in lactate dehydrogenase leakage and cell apoptosis, which were similar to 4-phenylbutyric acid (PBA, an ER stress inhibitor). Besides, similar to PBA, D4F inhibited gly-HDL-induced ER stress response activation evaluated through the decreased PERK and eIF2α phosphorylation, together with reduced ATF6 nuclear translocation as well as the downregulation of GRP78 and CHOP. Interestingly, D4F facilitated gly-HDL-triggered activation of autophagy, measured as elevated levels of beclin-1, LC3-II, and ATG5 expressions in macrophages. Furthermore, the inhibition effect of D4F on gly-HDL-induced ER stress-CHOP-induced apoptosis of macrophages was restrained after beclin-1 siRNA and 3-methyladenine (3-MA, an inhibitor of autophagy) treatments, while this effect was further reinforced after rapamycin (Rapa, an inducer of autophagy) treatment. Furthermore, administering D4F or Rapa to T2DM mice upregulated LC3-II and attenuated CHOP expression, cell apoptosis, and atherosclerotic lesions. However, the opposite results were obtained when 3-MA was administered to these mice. These results support that D4F effectively protects macrophages against gly-HDL-induced ER stress-CHOP-mediated apoptosis by promoting autophagy.

CEACAM1 Inhibited IκB-α/NF-κB Signal Pathway Via Targeting MMP-9/TIMP-1 Axis in Diabetic Atherosclerosis

Atherosclerosis (AS) is the most common and serious complication in type 2 diabetes mellitus (T2DM). Recent studies have emphasized that inflammation is the main cause of atherosclerosis. Studies have shown that carcinoembryonic antigen-related cellular adhesion molecule 1 (CEACAM1) regulates the expression of matrix metallopeptidase 9 (MMP-9) after ischemic stroke to reduce inflammation. The aim of this study was to elucidate potential molecular mechanism of CEACAM1 on the inflammatory response in atherosclerosis. The serum levels of CEACAM1, MMP-9, and tissue inhibitors of metalloproteinase 1 (TIMP-1) in T2DM patients and healthy control was detected. The results showed that the levels of CEACAM1 and TIMP-1 were significantly decreased, and the levels of MMP-9 were significantly higher than those in the control group. Moreover, we also observed the effect of CEACAM1 on atherosclerosis in T2DM rats. Hematoxylin & eosin (HE) staining and oil red staining showed that CEACAM1 recombinant protein reduced intima-media thickness and the area of atherosclerotic plaques. To further explore the molecular mechanism of CEACAM1 regulating MMP-9/TIMP-1, we conducted experiments in rat aorta vascular endothelial cells and rat aorta smooth muscle cells. The result showed that CEACAM1 inhibits inflammatory response via MMP-9/TIMP-1 axis. Taken together, CEACAM1 attenuates diabetic atherosclerosis by inhibition of IκB/NF-κB signal pathway via MMP-9/TIMP-1 axis, which indicate that CEACAM1 is potentially amenable to therapeutic manipulation for clinical application in atherosclerosis in T2DM.

The Multi-Therapeutic Role of MSCs in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common diabetes mellitus (DM) microvascular complications, which always ends with end-stage renal disease (ESRD). Up to now, as the treatment of DN in clinic is still complicated, ESRD has become the main cause of death in diabetic patients. Mesenchymal stem cells (MSCs), with multi-differentiation potential and paracrine function, have attracted considerable attention in cell therapy recently. Increasing studies concerning the mechanisms and therapeutic effect of MSCs in DN emerged. This review summarizes several mechanisms of MSCs, especially MSCs derived exosomes in DN therapy, including hyperglycemia regulation, anti-inflammatory, anti-fibrosis, pro-angiogenesis, and renal function protection. We also emphasize the limitation of MSCs application in the clinic and the enhanced therapeutic role of pre-treated MSCs in the DN therapy. This review provides balanced and impartial views for MSC therapy as a promising strategy in diabetic kidney disease amelioration.

[Research progress on effects of high glucose microenvironment on biological activity of adipose-derived stem cells]

Objective

To summarize the research progress of the effects of high glucose microenvironment on the biological activity of adipose-derived stem cells (ADSCs).

Methods

The literature on the high glucose microenvironment and ADSCs at home and abroad in recent years was reviewed, and the effects of high glucose microenvironment on the general characteristics, differentiation potential, angiogenesis, and nerve regeneration of ADSCs were summarized.

Results

The accumulation of advanced glycosylation end products (AGEs) in the high glucose microenvironment led to changes in the biological activities of ADSCs through various pathways, including cell surface markers, proliferation, migration, multi-lineage differentiation, secretory function, and tissue repair ability. The ability of ADSCs to promote angiogenesis and nerve regeneration in high glucose microenvironment is still controversial.

Conclusion

High glucose microenvironment can affect the biological activity of ADSCs, and the effect and mechanism of ADSCs on angiogenesis and nerve regeneration in high glucose microenvironment need to be further studied.

Association of Genetic Polymorphisms in MicroRNAs With Type 2 Diabetes Mellitus in a Chinese Population

INTRODUCTION

MicroRNAs (miRNA) involved in the insulin signaling pathways deeply affect the pathogenesis of T2DM. The aim of this study was to assess the association between single nucleotide polymorphisms (SNP) of the related miRNAs (let-7f rs10877887, let-7a-1 rs13293512, miR-133a-1 rs8089787, miR-133a-2 rs13040413, and miR-27a rs895819) and susceptibility to type 2 diabetes mellitus (T2DM), and its possible mechanisms.

METHODS

Five SNPs in miRNAs (let-7f rs10877887, let-7a-1 rs13293512, miR-133a-1 rs8089787, miR-133a-2 rs13040413, and miR-27a rs895819) involved in the insulin signaling pathways were selected and genotyped in a case-control study that enrolled 371 T2DM patients and 381 non-diabetic controls. The individual SNP association analyses, interaction analyses of SNP-SNP, SNP-environmental factors were performed. The effect the risk-associated polymorphism on regulating its mature miRNA expression was also evaluated.

RESULTS

In overall analyses, miR-133a-2 rs13040413 and let-7a-1 rs13293512 were related to the susceptibility to T2DM. In stratified analyses, miR-133a-2 rs13040413, let-7a-1 rs13293512 and miR-27a rs895819 showed associations with T2DM in the age ≥ 60 years subgroup. Moreover, let-7a-1 rs13293512 and miR-27a rs895819 showed associations with T2DM in male subgroup. In SNP-environmental factors interaction analyses, there were interaction effects of miR-133a-2 rs13040413 with dyslipidemia, let-7a-1 rs13293512 with smoking, and let-7a-1 rs13293512 with dyslipidemia on T2DM. In SNP-SNP interaction analyses, there were also interaction effects of miR-133a-1 rs8089787 with let-7a-1 rs13293512, and miR-133a-1 rs8089787 with let-7f rs10877887 on T2DM. Furthermore, for miR-133a-2 rs13040413, the variant T allele showed a trend toward decreased miR-133a expression in comparison with the wild C allele. For let-7a-1 rs13293512, the variant C allele expressed a lower let-7a compared to the wild T allele.

CONCLUSION

MiRNAs polymorphisms involved in the insulin signaling pathways and the interaction effects of SNP-SNP, SNP-environmental factors were related to T2DM susceptibility in a Chinese population.

Adipose-Derived Stem Cell Transplantation Inhibits Vascular Inflammatory Responses and Endothelial Dysfunction in Rats with Atherosclerosis

PURPOSE

This study aimed to investigate the effect of adipose-derived stem cell (ADSC) transplantation on atherosclerosis (AS) and its underlying mechanisms.

MATERIALS AND METHODS

In our study, rat AS model was established, and ADSCs were isolated and cultured. Atherosclerotic plaque and pathological symptoms of thoracic aorta were measured by Oil Red O staining and Hematoxylin-Eosin staining, respectively. Total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were measured by an automatic biochemical analyzer. Expressions of vascular endothelial growth factor (VEGF), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), aortic endothelin-1 (ET-1), interleukin-6 (IL-6), c-reactive protein (CRP), and tumor necrosis factor α (TNF-α) were measured by enzyme linked immunosorbent assay, VEGF, VCAM-1, ICAM-1, ET-1, respectively, and NF-κB p65 mRNA expressions were detected by quantitative real-time polymerase chain reaction. Protein expressions of VEGF, VCAM-1, ICAM-1, ET-1, NF-κB p65, p-NF-κB p65, and IκBα were measured by western blot. Moreover, NF-κB p65 expression was measured by immunofluorescence staining.

RESULTS

ADSC transplantation alleviated the pathological symptoms of aortic AS. ADSC transplantation decreased the levels of TC, TG, and LDL-C and increased serum HDL-C level. Meanwhile, ADSC transplantation decreased the levels of IL-6, CRP, and TNF-α in AS rats. Moreover, the expressions of VEGF, ET-1, VCAM-1, and ICAM-1 were decreased by ADSC transplantation. ADSC transplantation inhibited phosphorylation of NF-κB p65 and promoted IκBα expression in AS rats.

CONCLUSION

Our study demonstrated that ADSC transplantation could inhibit vascular inflammatory responses and endothelial dysfunction by suppressing NF-κB pathway in AS rats.

Applicability of adipose-derived mesenchymal stem cells in treatment of patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is mainly characterized by insulin resistance (IR) and impaired insulin secretion. The chronic inflammatory process contributed to IR and could also hamper pancreatic β cell function. However, currently applied treatment cannot reverse β cell damage or alleviate inflammation. Mesenchymal stem cells (MSCs), the cell-based therapy for their self-renewable, differentiation potential, and immunosuppressive properties, have been demonstrated in displaying therapeutic effects in T2DM. Adipose-derived MSCs (AD-MSCs) attracted more attention due to less harvested inconvenience and ethical issues commonly accompany with bone marrow-derived MSCs (BM-MSCs) and fetal annex-derived MSCs. Both AD-MSC therapy studies and mechanism explorations in T2DM animals presented that AD-MSCs could translate to clinical application. However, hyperglycemia, hyperinsulinemia, and metabolic disturbance in T2DM are crucial for impairment of AD-MSC function, which may limit the therapeutical effects of MSCs. This review focuses on the outcomes and the molecular mechanisms of MSC therapies in T2DM which light up the hope of AD-MSCs as an innovative strategy to cure T2DM.

Targeted Migration of Human Adipose-Derived Stem Cells to Secondary Lymphoid Organs Enhances Their Immunomodulatory Effect and Prolongs the Survival of Allografted Vascularized Composites

The targeted delivery of therapeutic agents to secondary lymphoid organs (SLOs), which are the niches for immune initiation, provides an unprecedented opportunity for immune intolerance induction. The alloimmune rejection postvascularized composite allotransplantation (VCA) is mediated by T lymphocytes. Human adipose-derived stem cells (hASCs) possess the superiority of convenient availability and potent immunoregulatory property, but their therapeutic results in the VCA are unambiguous thus far. Chemokine receptor 7 (CCR7) can specifically guide immune cells migrating into SLOs. There, the genes of CCR7-GFP or GFP alone were introduced into hASCs by lentivirus. hASCs/CCR7 maintained the multidifferentiation and immunoregulatory abilities, but it gained the migration capacity elicited by secondary lymphoid organ chemokine (SCL) (CCR7 ligand) in vitro. Noteworthily, intravenously infused hASCs/CCR7 targetedly relocated in the T-cell aggression area in SLOs. In a rat VCA model, hASCs/GFP transfusion had a rare effect on the allografted vascularized composite. However, hASCs/CCR7 infusion potently prolonged the grafts' survival time. The ameliorated pathologic exhibition and the regulated inflammatory cytokines in the peripheral blood were also observed. The altered axis of Th1/Th2 and Tregs/Th17 in SLOs may underlie the downregulated rejection response. Moreover, the proteomic examination of splenic T lymphocytes also confirmed that hASCs/CCR7 decreased the proteins related to cytokinesis, lymphocyte proliferation, differentiation, and apoptotic process. In conclusion, our present study demonstrated that targeted migration of hASCs/CCR7 to SLOs highly intensifies their in vivo immunomodulatory effect in the VCA model for the first time. We believe this SLO-targeting strategy may improve the clinical therapeutic efficacy of hASC for allogeneic and autogenic immune disease. Stem Cells 2019;37:1581-1594.

Adipose-derived stromal/stem cells from different adipose depots in obesity development

The increasing prevalence of obesity is alarming because it is a risk factor for cardiovascular and metabolic diseases (such as type 2 diabetes). The occurrence of these comorbidities in obese patients can arise from white adipose tissue (WAT) dysfunctions, which affect metabolism, insulin sensitivity and promote local and systemic inflammation. In mammals, WAT depots at different anatomical locations (subcutaneous, preperitoneal and visceral) are highly heterogeneous in their morpho-phenotypic profiles and contribute differently to homeostasis and obesity development, depending on their ability to trigger and modulate WAT inflammation. This heterogeneity is likely due to the differential behavior of cells from each depot. Numerous studies suggest that adipose-derived stem/stromal cells (ASC; referred to as adipose progenitor cells, in vivo) with depot-specific gene expression profiles and adipogenic and immunomodulatory potentials are keys for the establishment of the morpho-functional heterogeneity between WAT depots, as well as for the development of depot-specific responses to metabolic challenges. In this review, we discuss depot-specific ASC properties and how they can contribute to the pathophysiology of obesity and metabolic disorders, to provide guidance for researchers and clinicians in the development of ASC-based therapeutic approaches.

Endoplasmic reticulum stress-dependent autophagy inhibits glycated high-density lipoprotein-induced macrophage apoptosis by inhibiting CHOP pathway

This study was designed to explore the inductive effect of glycated high‐density lipoprotein (gly‐HDL) on endoplasmic reticulum (ER) stress‐C/EBP homologous protein (CHOP)‐mediated macrophage apoptosis and its relationship with autophagy. Our results showed that gly‐HDL caused macrophage apoptosis with concomitant activation of ER stress pathway, including nuclear translocation of activating transcription factor 6, phosphorylation of protein kinase‐like ER kinase (PERK) and eukaryotic translation initiation factor 2α, and CHOP up‐regulation, which were inhibited by 4‐phenylbutyric acid (PBA, an ER stress inhibitor) and the gene silencing of PERK and CHOP. Similar data were obtained from macrophages treated by HDL isolated from diabetic patients. Gly‐HDL induced macrophage autophagy as assessed by up‐regulation of beclin‐1, autophagy‐related gene 5 and microtubule‐associated protein one light chain 3‐II, which were depressed by PBA and PERK siRNA. Gly‐HDL‐induced apoptosis, PERK phosphorylation and CHOP up‐regulation were suppressed by rapamycin (an autophagy inducer), whereas aggravated by 3‐methyladenine (an autophagy inhibitor) and beclin‐1 siRNA. Administration of diabetic apoE^−/− mice with rapamycin attenuated MOMA‐2 and CHOP up‐regulation and apoptosis in atherosclerotic lesions. These data indicate that gly‐HDL may induce macrophage apoptosis through activating ER stress‐CHOP pathway and ER stress mediates gly‐HDL‐induced autophagy, which in turn protects macrophages against apoptosis by alleviating CHOP pathway.

Diabetic Human Adipose-Derived Stem Cells Accelerate Pressure Ulcer Healing by Inducing Angiogenesis and Neurogenesis

Adipose-derived stem cells (ASCs) possess a well-characterized capacity to enhance cutaneous wound healing. However, many controversies exist regarding ASCs from diabetic patients (dASCs). No report exists on the administration of dASCs for the treatment of pressure ulcers. The aim of this study was to compare properties of dASCs and nondiabetic ASCs (nASCs). In addition, we studied if dASCs enhanced pressure ulcer healing in a rodent pressure ulcer model and investigated underlying mechanisms. We found similar expression of cell surface markers and characteristics in dASCs and nASCs, although dASCs exhibited decreased proliferation and osteogenic differentiation capacity and enhanced adipogenic differentiation capacity. dASCs had beneficial effects on chronic wound healing, though some aspects of their capacity were impaired. The ability of dASCs to promote nerve regeneration was not compromised. dASCs promoted pressure ulcer healing and improved healing by modulating inflammation, promoting angiogenesis and neuroregeneration, enhancing collagen deposition, and increasing re-epithelization. These data may provide a theoretical foundation for further clinical administration of ASCs for chronic wound healing in patients with diabetes.

Adipose-derived cellular therapies in solid organ and vascularized-composite allotransplantation

PURPOSE OF REVIEW

Controlling acute allograft rejection following vascularized composite allotransplantation requires strict adherence to courses of systemic immunosuppression. Discovering new methods to modulate the alloreactive immune response is essential for widespread application of vascularized composite allotransplantation. Here, we discuss how adipose-derived cellular therapies represent novel treatment options for immune modulation and tolerance induction in vascularized composite allotransplantation.

RECENT FINDINGS

Adipose-derived mesenchymal stromal cells are cultured from autologous or allogeneic adipose tissue and possess immunomodulatory qualities capable of prolonging allograft survival in animal models of vascularized composite allotransplantation. Similar immunosuppressive and immunomodulatory effects have been observed with noncultured adipose stromal-vascular-fraction-derived therapies, albeit publication of in-vivo stromal vascular fraction cell modulation in transplantation models is lacking. However, both stromal vascular fraction and adipose derived mesenchymal stem cell therapies have the potential to effectively modulate acute allograft rejection via recruitment and induction of regulatory immune cells.

SUMMARY

To date, most reports focus on adipose derived mesenchymal stem cells for immune modulation in transplantation despite their phenotypic plasticity and reliance upon culture expansion. Along with the capacity for immune modulation, the supplemental wound healing and vasculogenic properties of stromal vascular fraction, which are not shared by adipose derived mesenchymal stem cells, hint at the profound therapeutic impact stromal vascular fraction-derived treatments could have on controlling acute allograft rejection and tolerance induction in vascularized composite allotransplantation. Ongoing projects in the next few years will help design the best applications of these well tolerated and effective treatments that should reduce the risk/benefit ratio and allow more patients access to vascularized composite allotransplantation therapy.